Wikipedia:Reference desk/Archives/Science/October 2005

Greatest Common Factor / Least Common Multiple Problem

I recently went to a math competition and this problem is bugging the heck out of me. Can anyone show how to solve it as well as provide the useful laws?

Q) A positive integer 'n' has the property that the least common multiple of n and 36 is 500 greater than the greatest common factor of n and 36. What is 'n'? Written mathematically: LCM(36,n) – 500 = GCF(36,n)... n=?

Thanks C. Nelson 22:26, 2 October 2005 (UTC)

Earliest Fossil Egg

Where was the earliest fossil egg found?

-anon

As yet, we do not have an article on Fossil eggs nor does our fossil article provide much detail. However, these articles by The San Francisco Chronicle on dinosaur fossil eggs [1] and the National Geographic on bird fossil eggs [2] should be of some assistance to you. I have added Fossil eggs to Wikipedia:Requested Articles so that someone can write an article on this topic. Capitalistroadster 00:08, 23 September 2005 (UTC)

which part of the tree contains live wood?

• Depends on the tree, but potentially all of it. -- Jmabel | Talk 05:34, 23 September 2005 (UTC)
  • Well, it does depend on the tree, but most "normal" trees (not, for example, palm trees) have living cells in the outer sections of their trunks (except the bark) and dead cells in the interior and the bark.

    Details: There is a thin, roughly cylindrical shell called the vascular cambium, which is where a tree does its growing. The outside of the cambium produces new phloem cells, which do "food" transport. The inside of the cambium produces new xylem cells, which do water & nutrient transport from the roots. Old phloem gets shed with the bark, but old xylem just sticks around, forming a core made of dead cells that provides structural support to the tree. Most trees add a new layer of xylem each year. The old dead xylem layers are the rings one can see on a stump.

    It appears to little-old-nonexpert-me that this ability to make a single, strong core out of dead xylem is probably one of the main factors that allows trees to grow so tall. Lots of plants have this phloem/cambium/xylem structure, but in many of the smaller ones, the cambium does not form a single large cylinder, but rather many small ones (vascular bundles). Thus, the xylem is scattered and strength is lost. I imagine this is one reason you will never see (say) a celery tree. On the other hand, the multiple bundles probably allow for faster growth ("growing like a weed"). Interestingly, palm trees have the multiple vascular bundles, but can still form large, strong trunks.

    Much of this is hinted at in our tree and xylem articles, but never quite stated. Maybe it should be.

    — Nowhither 00:14, 24 September 2005 (UTC)

Any Airsofters in the LA county area?

Any Airsofters in the LA county area?

Oh Jesus Christ. Is the concept of the Reference Desk that dense and foreign to some people? Garrett Albright 12:21, 23 September 2005 (UTC)

That's a valid question, just not the kind you want to answer. Superm401 | Talk 13:44, 23 September 2005 (UTC)

• It's an easy question to answer, and perfectly valid. Given the huge population of LA, and the burgeoning popularity of Airsoft, the answer is indubitably, "Yes". --jpgordon∇∆∇∆ 14:38, 23 September 2005 (UTC)

• Okay, please do not bite the newcomers. To the original poster: The answer is "yes", there are airsoft players in that area. Perhaps you are one of them. However, that is obvious. I would guess that your real reason for posting here is to meet airsoft players (?). If so, then you are in the wrong place. The Wikipedia Reference desk is for answering factual questions, not for meeting people. A quick Google search turns up many airsoft-oriented websites. I suggest you try one of them. — Nowhither 00:20, 24 September 2005 (UTC)

Electron – Proton

What we have been taught is that electron revolves around a proton because of electromagnetic force of attraction. But this force is same for both the electron and proton. This is when we neglect other forces like Gravitation since it is only 1/100 th times of electromagnetic force acting. Then why do electrons revolve around the protons instead protons can move around an electron??

Yes, the force on the two is the same (in accord with Newton's third). However, the proton is 2000 times more massive that the electron, so it remains relatively stationary. Just like the Earth orbiting the Sun, both objects actually orbit the center of mass, but the center of mass is closer to the more massive body. In both cases, the more massive body is so much more massive, that you can often neglect the massive body's revolution. -Lethe | Talk 02:24, 23 September 2005 (UTC)

Isn't it a bit 'oldfashioned' to think of an electron evolving around the nucleus? This is 'particle-thinking', but elementary particles can also be seen as waves. I envision electrons and other 'particles' as sort of pulsating three-dimensional waves. Lomn mentions in 'Volume of the proton' above, that the position of electrons can only be expressed in probablistic terms. If the electron can als be seen as revolving around the nucleus then I can only rhyme all this together by seeing the electron as occupying the same space (on average) as the nucleus, just covering a wider area. So the amplitude of the wave would have to be (much) bigger. If I'm talking gibberish feel free point that out to me :) . DirkvdM 14:00, 23 September 2005 (UTC)

When one starts discussing particles as small as this, the distinction between particle and wave mechanics gets blurred, since both properties can be present when quantum effects present themselves. Discussing it in probablistic terms is one way of expressing it, but there is a mode of thought that a paricle really occupies a 'quantum area' of space and exists everywhere in that space simultaneously, whereas probablistic theory suggests it has a chance of being at an point based upon a formula.

It is a bit "old-fashioned", yes, but it is not too far from the truth. "Electrons evolve around a positively-charged nucleus, to which the are attracted by Coulombic (electrostatic) forces" is a correct statement: they just don't obey Kepler's laws... Physchim62 14:32, 23 September 2005 (UTC)

It is old-fashioned (which doesn't stop almost every physics student from doing the calculation at some point), but the principle still applies. When treating the proton and electron as a two-body problem, you can reduce it to a one-body problem with a reduced mass orbiting about the center of mass. Since the electron is so much smaller than the proton, the reduced mass is basically the electron mass, and the center of mass is basically the proton position, so you're basically solving a problem with a stationary proton.

When you actually treat the situation quantum mechanically, it turns out that you can make the same transforms (it's the same potential afterall), and you end up solving a quantum mechanical problem of a reduced mass in a symmetric potential about the center of mass. So although the result is different, you can make some of the same conclusions: that the proton is relatively unaffected and that the solutions for the wavefunction of the reduced mass will basically be the wavefunction (orbitals) of the electron. There's more information at hydrogen atom and hydrogen-like atom. — Laura Scudder | Talk 14:32, 23 September 2005 (UTC)

Wintergreen LifeSavers

Why do wintergreen lifesavers "spark" when chewed? ---12.37.12.134 --12.37.12.134 02:29, 23 September 2005 (UTC)

It appears to be a form of triboluminescence. This seems a useful explanation.-gadfium 03:40, 23 September 2005 (UTC)

The American roulette?

If two persons both eat the same amount of beef each and every day from the same large pool of cattles, which person is more likely to get mad cow disease in the long run?

1. Mr. A: Eat hamburgers made from grinding and mixing many many many cattles' meat.
2. Mr. B: Buy a frozen cattle carcass each time and eat the dead body from head to tail.

I guess Mr. A's risk is much higher than Mr. B's. But could it be possible that by mixing a few thousand dead cattle's meat at a time, the concentration of bad prion would become too low to be threatening? -- Toytoy 03:38, 23 September 2005 (UTC)

In the UK, it's thought those who got vCJD generally got it through hamburgers and the like. Bad slaughtering practices are much more problematic when you don't do it yourself and then mince the remains to cover any mistakes... Shimgray 11:56, 23 September 2005 (UTC)

I would agree that it's Mr. A because the smallest piece of meat you can realistically grind is still probably large enough to contain millions of prions. Superm401 | Talk 13:41, 23 September 2005 (UTC)

OK, I know you can't use meat puree to make a good hamburger. A piece of hamburger, in theory, may only have hundreds of cattles' meat in it. Then how about sausages such as hot dogs? These products are manufactured in very big factorie (lots of cattles), the meat is pulverized and then thoroughly mixed. Does it make franks more dangerous than hamburgers? -- Toytoy 14:05, 23 September 2005 (UTC)

More cows means more dilution, so the amount of germs you ingest may be below some threshold. I've heard that in order to get malaria you have to get bitten by an infected mosquito several times (don't know how many and over what period of time). Mad cow disease might be completely different though. Just a consideration. DirkvdM 14:20, 23 September 2005 (UTC)

Look again at what I said above. A grinder(not blender) probably outputs shreds of meat that are maybe about, say, half a gram. I don't know how many prions could fit in that, but I'm pretty sure it's 100s of 1000s. I think that's enough to infect you. Then again, I could be wrong. But there's my argument. Superm401 | Talk 20:48, 23 September 2005 (UTC)

Difficult to say, because we don't know the level of infectiousness of the prion involved, but my feeling would be that route A is more hazardous (for the reasons discussed above). Physchim62 14:37, 23 September 2005 (UTC)

1. 1 is eating many many cattle over a long period of time. #2 is eating one cattle over a long period of time. Assuming every cow you eat has an equal chance of having bad prions in it (big, artificial assumption), it would seem that #1 would be more statistically more hazardous. --Fastfission 22:51, 23 September 2005 (UTC)

I guess it is still unknow how much prion would cause one to be infected. If we hire many vegetarians and feed them infected meat and wait a decade, we may learn what are the minimum prion concentrations to infect 10%, 20%, ... 50%, ... 90% and 100% of people after consumption of a portion of beef. But we simply cannot try this on people ... at least to vegitarians.

Had anyone tried this on animals? -- Toytoy 00:40, 24 September 2005 (UTC)

To bring a bit of perspective to the whole "mad cow" panic, it's worth remembering that in the 20-or-so years since BSE became apparent, fewer than 160 humans have died in the entire world from nvCJD. Eating lots of hamburgers is vastly more likely to kill you from heart disease than CJD. -- Arwel 13:24, 24 September 2005 (UTC)

Very possibly, many cases were not diagnosed, some of them are still hidden, but the actual numbers may still be a very low number in comparison of other kinds of deadly food poisoning or long term health hazards (tran fat, salt, cholesterol ... problems).

I guess it is because this disease has a very low rate of transmission among animals and humans. A cow eating dead cows has a very low chance to get the disease. A man eating infected cows also does not ge it most of the times. However the rate is not that low to make this disease a non-issue.

I also wonder if dilution plays a part in lowering the rate of infection. Are hamburgers more dangerous than steaks? Are hot dogs even more dangerous? Shall we restrict or increase the size of the batc during meat processing if mad cow is the only concern?

If a tiny itsy bitsy piece of meat is infectious, then an infected cow broken apart into a million pieces may infect hundres if not thousands people. If that itsy bitsy piece of meat is not infectious, then possibly no one gets mad cow because of it. -- Toytoy 14:54, 24 September 2005 (UTC)

Read the article on prions. Even one madcow prion can infect a human. Since this prion predominantly affects the central nervous system, the risk of the two persons would depend on how the animal(s) is/are slaughtered. If care is taken to avoid knifing the CNS's (most infectious part) of the mass-load of cows, but not the one .... Besides, cooking the meat to the point of denaturing the prion would nullify the risk. Mad cow has been around forever under the name "Creutzfeldt-Jakob disease" and you probably have as good a chance of catching it from one of those few people as you do from the cow meat.

Oil

For some reason, my face is always oily, why does this happen and is there a way of preventing it from happening?

Thanks, Tasha

The simple answer is that skin oils help protect your body against attack by microorganisms. Excess production can be due to many factors that vary greatly from person to person, including, but not limited to, diet, exercise, climate, medical conditions, and ethnicity. I think it would be a good idea to talk about this with your family doctor, who is more knowledgeable about your circumstances than we are.--inks 06:56, 23 September 2005 (UTC)

What is evolution?

See evolution. - Fredrik | talk 04:59, 23 September 2005 (UTC)

Bermuda Triangle

What is Bermuda Triangle?

• See Bermuda Triangle. -- Jmabel | Talk 05:36, 23 September 2005 (UTC)

branded product marketing

(no question asked)

Did you have a question? — Nowhither 00:24, 24 September 2005 (UTC)

Start with category:brands. -- Ancheta Wis 23:07, 1 October 2005 (UTC)

Quarks

Are there important differences between atomic nuclei and quark matter such as quark-gluon plasma? How can it be experimentally determined that a nucleus is composed of distinct nucleons? ‣ᓛᖁᑐ 05:33, 23 September 2005 (UTC)

• For the second question, the idea has been round since Prout's hypothesis in the early nineteenth century. The integral nature of atomic number was demonstrated by Henry Moseley, who discovered what is now known as Moseley's law. The last major paradox was resolved by the work of Francis William Aston, who demonstrated the existence and integral mass of isotopes. Physchim62 19:46, 24 September 2005 (UTC)

australian native animals

where is the emu found in australia?

Throughout most of it. See [3]--inks 06:46, 23 September 2005 (UTC)

Or you could try our article on emus, which has a picture representing their range. --Robert Merkel

Although generally not in metropolitan areas, I've never seen an emu near the city, so generally rural areas on the map at emu. --Commander Keane 10:50, 23 September 2005 (UTC)

Why does wind gust?

I know that wind is caused by air movements from areas of different pressure – and the closer these areas of different pressure are to each other the stronger the wind it. I also think I know that its the rotation of the earth that stops it all evening out into one average pressure area. I don't understand though why the windspeeds are not constant but they gust – sometimes much more than others? Thryduulf 08:10, 23 September 2005 (UTC)

Because pressures are not a constant, even in a given location at a particular time of year. Chaotic variations in temperature and water vapor concentrations mean pressures are always changing as well. This in turn results in varying windspeeds. Superm401 | Talk 13:35, 23 September 2005 (UTC)

Does it cause cancer?

My friend asked me an uncertain question concerning blood clotting (coagulation), so I got Wiki to help him solve his question, here it is: Does it cause cancer (anything cancer, like blood cancer etc) if sb had serious blood clotting?

• Excessive blood clotting is certainly a problem, but as far as I know it doesn't cause cancer. Cancers are malignant cells with excessive growth and even they need an uninterrupted blood flow to deliver nutrients to their cells. So I would say serious coagulation is just as bad for cancers as it is for normal tissue. See Cancer and Leukemia and for more info. - 131.211.210.12 11:13, 23 September 2005 (UTC)
  • Even if excessive blood clotting -did- lead to cancer, you would not live long enough for it to grow to any significant size. You would almost certainly die of a heart attack or stroke not long after blood clots started forming in your circulatory system.--inks 12:05, 23 September 2005 (UTC)

Usually the causal relationship runs the other way—a cancer that affects the blood-forming tissue of the body (the bone marrow) leads to over- or under-proliferation of megakaryocytes–cells that turn into platelets and cause clotting–leading to clotting disorders.

Large tumours secrete chemical signals that drive angiogenesis:the formation of new blood vessels. (Without a blood supply, cells at the center of a large tumour don't receive sufficient nutrients and oxygen, and the tumour stops growing.) These new blood vessels tend to be irregularly formed and tortuous in shape; the blood flow in them is turbulent and disordered. This turbulent flow tends to encourage clot formation; those clots can be dislodged and cause trouble elsewhere in the body.

Also, there is a correlation between deep vein thrombosis or pulmonary embolism (blood clots in the deep veins of the leg and clots in the lung, respectively) and diagnosis (recent past or future) with cancer. The mechanism for this is not well understood (as far as I know) but probably has to do with clotting stimulated by inflammation of tissue around the tumour site.

So to answer your question—no, clots probably don't cause cancer. Cancer, however, can cause clots. TenOfAllTrades(talk) 13:27, 23 September 2005 (UTC)

Example tutorial of TI-92PLUS

Do anybody know about the usage of TI-92PLus?I recently given a assignment which want me to write a programme by using this calculator.If possible,please give me some examples or tutorial of the programme?Is there any websites related to the programming of this calculator too?Thanks.

I suggest you start by reading the manual, if it's anything like the one for the TI-83 Plus, you'll find plenty of examples in there. --Pidgeot (t) (c) (e) 13:42, 23 September 2005 (UTC)

I agree. The TI-83 Plus manual is excellent, I made a game on it with no other reference. Bart133 (t) 23:27, 28 September 2005 (UTC)

\offtopic Well, it's got to be better than the HP-39G+ manual. I'm trying to learn how to program this and the manual actually tells you how to use about four commands, then says "The functionality of the rest of the commands is left as an exercise to the reader". splintax ^(talk) 09:40, 30 September 2005 (UTC)

Help using Internet explorer

I am using Internet explorer. All these days, I used to download pages, disconnect, and view pages later. But suddenly, for the last ten days, when I close the browser windows and open it later, I cant view pages offline. It says 'page not available offline'. What should I do? I tried by going to Internet options, but after that dont know what to do. Please help.

Your cache may be filled. Try clearing it through Internet Options, as well as verifying that its settings are correct.

Alternatively, you can use Save As to save a (temporary) copy of the page to yuor harddrive so you can view it from there after you disconnect. --Pidgeot (t) (c) (e) 17:20, 23 September 2005 (UTC)

If you install another browser (and while you're at it, why not make it a better one like Mozilla, Firefox or Opera ... ) and try it with that, then at least you'll know if the fault lies with the browser or that you should look elsewhere. This is also a much more general tip. Keep an alternative handy, such as a second ('free') internet connection. DirkvdM 06:28, 24 September 2005 (UTC)

You might also wanna check you are visiting the same pages. Some script-generated pages cannot be cached by the browser.--Fangz 12:58, 26 September 2005 (UTC)

I think the questioner is using the "offline pages" functionality in IE to save a cache of pages so that they can go back and look at them later on, without connecting (presumably they're using a dial-up connection). Try clicking "Favourites", and "Add to favourites" on the website you want to cache, and then select "make available offline" and click Customize. Follow the instructions and you should get the problem sorted out. :-) splintax ^(talk) 04:13, 3 October 2005 (UTC)

what exactly is a buckeye

Have you checked buckeye? In the context of Ohio State, it refers to the first entry in the disambiguation. — Lomn | Talk / RfC 17:54, 23 September 2005 (UTC)

Thunder/lightening

I have read both the articles related to this subject but I'm still not sure about one thing. Can thunder occur without the presence of lightning, and visa versa. Thanks, DEE

Lightning causes thunder, so as a general rule, no and no. However, many things other than lightning can cause sounds similar to thunder (explosions, sonic booms, and so forth) and it's not always possible to observe both lightning and thunder at once. — Lomn | Talk / RfC 18:24, 23 September 2005 (UTC)

Ehm, when you observe thunder and lightning at once you might not be able to tell the tale :) . But more seriously, there are different sorts of lightning, such as Ball Lightning, which makes a crackling sound if any at all. Strangely, the lightning article doesn't mention St. Elmo's Fire (which I'll amend next), which, I imagine, won't make any sound either. By the way, my grandmother once saw a lightning ball come in through a window, hover for a bit, and go out again. Only after her death did people learn that such things really exist. The poor woman was branded a liar. No-one ever believed her. DirkvdM 06:53, 24 September 2005 (UTC)

Someone did a lecture about ball lightning in a class I had the other day, but they were fairly vague and seemed to write it off as almost pseudoscience. I'm off to check out that article – thanks for the reminder. :) splintax ^(talk) 09:48, 30 September 2005 (UTC)

Austim and Music Therapy

I am looking for any information on the treatment of autistic children through music therapy. Anything about it's effectiveness, methods, etc, would be incredibly helpful. I would also like to find any information disagreeing with this method. Thank you so much.

anon

• I don't know the answer to your question, but hopefully you can find something by reading our article on autism and the list of autism-related topics. I believe there are several Wikipedians with a special personal interest in autism, so that area has received some attention. Bovlb 19:39, 23 September 2005 (UTC)

Genetic Engineered Food

Seems to me the risks far outweigh the benefits, yet USA Agribusiness is gung ho headed that way. Am I missing something, or is there a failure of government oversight of a business area that does not give good enough lip service to quality of safety?

Risks:

• Many nations want grain, and animal products from grairi, where there was no genetic engineering. The USA is no longer able to serve those markets, because of massive contamination, and inability to police the contamination. For example, a farmer who tries to make the pure product, cannot, because contamination is freely in the winds that other farms "breathe." Thus, as genetically engineered byproducts filter down the food chain, the USA locks itself out of more global markets.
• Today in much of South and Central America, and southern states of USA, there is a real serious problem with Killer Bees. This is a man made problem, that came about thanks to experiments in breeding a better honey producer, but the experiment had very negative consequences.
• Once upon a time, there was Mad Sheep disease (Scrapie) caused by short cuts in managing food supply in agriculture, which spread to cattle, so then there was Mad Cow disease, then there were experiments to try to understand this using Deer in captivity, deliberately given the disease so that we had Mad Deer, but due to the experimenters not understanding how the disease could spread, the Mad Deer in captivity licked fences, which were also licked by Wild Deer at edges of the enclosures, so now Mad Deer was in the wild, and eventually spread to all of North America, which gave the disease back to animals in agriculture, such as pigs, and to the animals that eat Deer, such as mountain lions. So we are on a collision course with a worse disaster, fueled by efforts to do cost savings in agriculture, with government oversight that is driven by rear view mirror to past disasters, rather than oversight of theories about future risks.

Benefits:

• When there is a wide range of quality of animals producing eggs milk meat, whatever, this is a breeding technique to make copies of those that are the best.
• Genetic engineering, cloning, and Transgenetics is a real cool thing to do. Any company that announces successes will get oodles of money from venture capitalists who think there's lots more profits down the road from this.
• Ok, we know there are major disasters down the road, but we can still make oodles of profits capitalizing on the industry that is exploring this high risk area, then hopefully get out of the business, before the disasters put them out of business.

AlMac|^(talk) 22:40, 23 September 2005 (UTC)

AlMac: The question of whether using genetically modified organisms to produce food is a Good Thing is one I will leave to you and others to decide. However, you missed some of the most important entries in the "benefits" list. Most of these, in the end, deal with cost. Using GMOs we can produce food more cheaply. We do this by creating GMOs that, compared to their natural counterparts:

• Produce more food.
• Have greater disease resistance.
• Mature faster.
• Can grow in more adverse climates.

By making food more cheaply, food producers get to spend less money. Someone might say, "Yes, because they are greedy." Well, I'm greedy too. I want a lower food bill. Don't you?

It should be noted that cost reductions also have applications in combating hunger in developing nations. As does creating a GMO that produces more nutritious food than its natural counterpart.

Lastly, I'd note that at least one of your "Risks" arguments isn't quite right. "Killer bees" were not created through modern genetic engineering, but through old-fashioned interbreeding. This phenomenon has been going on for thousands of years and, in general, has been quite safe and successful. A single isolated example is not a good argument against it. And it is certainly not an argument against modern genetic engineering, since it was not used in this case.

Again, I am not arguing a position here. I just saw that your list of "risks" and "benefits" seemed awfully lop-sided. You asked whether there has been a failure of government oversight. I'd say that is quite possible.

— Nowhither 00:44, 24 September 2005 (UTC)

And mad sheep, cow and deer diseases have nothing to do with genetic engineering (or am I now missing something?). Which leaves only the first risk from AlMac's list. Which is scary enough by itself. But I've heard of another one. Genetic engineering can also be used to make crops more resistant to pesticides, which means farmers may (and will) start using them more liberally, which has to have negative side-effects.

But more in general, genetic engineering is rather like a boosted form of old-fashioned interbreeding, which in turn is a boosted form of natural selection. In both cases things are left less to chance, which means developments go faster. And with interbreeding we've created a situation in which diseases can spread much faster. Whole fields of plants that are all the same means that if a disease is introduced it will spread very fast. Add to that that the plants are selected on specific traits and not others, thus possibly leaving out natural defence mechanisms we don't understand yet (and there's a whole lot we don't understand when it comes to the mechanisms in nature). The lack of biodiversity also means that if a disease spreads it will wipe out all plants. That's the result of the first boost. This second boost has a potential to go farther still, which is scary.

To come back to the original question. If all this is left entirely to private companies the risk is way too high that they won't care about the long-term effects. I'm ultimately in favour of using genetic engineering (if only for scientific research), but it has to be done with extreme care, not rushing things. And private companies are by their very nature not made of the right stuff to do this. This has to be done by governments. So yes, there's a failure of government oversight. Moreover, the governments of not just the US but in the whole world should not just restrict themselves to oversight, but completely take over the industry. We're meddling with something we don't sufficiently understand. DirkvdM 07:27, 24 September 2005 (UTC)

I see something missing from your list of benefits. It's not just more food, but we can get better food. A great example is golden rice, which is as easy to grow as normal varieties, but has more vitamin A. It was designed specifically to help areas with vitamin A shortages (like most of Africa File:Vitamin A deficiency.PNG). I think someone who wasn't used to a full belly might disagree on whether the risks really outweighed the benefits. — Laura Scudder | Talk 08:05, 24 September 2005 (UTC)

why is the sky blue

See Diffuse sky radiation. — Nowhither 00:47, 24 September 2005 (UTC)

The short answer is one quoted from a radio commercial I've been hearing lately: "All colors have wavelenghts that are diffused by oxygen and nitrogen. Since blue has the shortest wavelength, it's diffused up to ten times more, so the human eye sees more of it than any other color." I hope I haven't broken any rules by quoting that! Btw, what the heck did that article say? I couldn't make heads or tails of it. Hermione1980 01:01, 24 September 2005 (UTC)

No you didn't break any rules. See Fair use. What that means is this: oxygen and nitrogen are the two most common substances in air. "Diffused" in this case means "scattered". Light is a form of (very rapid) vibration, waves in other words; the wavelength of light is the distance it travels in a single vibration/wave. Different wavelengths of light are seen as different colors. Red is longest (in the visible range), then orange, yellow, green, with blue/violet being the shortest. Shorter wavelengths are scattered more. That means that red and yellow light tend to pass straight through the air, while blue light tends to bounce around a little. Almost all the light in the daytime sky comes from the sun. But blue, since it bounces around, may look like it is not coming straight from the sun, but rather from many directions. Thus, the sky, away from the sun, appears blue. — Nowhither 01:17, 24 September 2005 (UTC)

See also Rayleigh scattering. TenOfAllTrades(talk) 01:26, 24 September 2005 (UTC)

-1=1

A "proof" for the idea that -1=1 was posted on your page about the imaginary number i. I have replicated it in this question for quicker reference:

-1=i*i=sqrt(-1)*sqrt(-1)=sqrt(-1*-1)=sqrt(1)=1

However, your page says that this is incorrect because square roots only work for real, positive numbers. Your page on the number -1 says that -1^2/2=-1 and sqrt(-1^2)=1 therefore 1 cannot equal -1. However, a friend of mine says that this is incorrect because sqrt(-1^2)=sqrt(-1) though -1^2=1; I have written to you in order to resolve this dispute.

Thank you for your time and patience.

I'm not sure exactly what you're intending to say here because of the way you've written the math symbols. Can you go back and put gratuitous parentheses to make clear exactly what you mean(particularly at "-1^2/2=-1"). However, I can tell you you're friends wrong in saying sqrt((-1)^2)[by the way "-1^2" means "-(1^2)" so you should have said "(-1)^2" but I knew what you meant]. sqrt((-1)^2)=sqrt(1)=1, because the inside is simplified first by order of operations. Superm401 | Talk 01:16, 24 September 2005 (UTC)

This problem can be explained in several ways. My favorite explanation is that there is no "nice" function called "sqrt" on the complex numbers. Numbers have two square roots. But a function has to have a single value. When we deal with square roots of positive real numbers, we fix this by letting "sqrt" of a positive real number be the positive square root, not the negative one. But there is no nice way to fix this problem for complex numbers in general. This is probably what was meant by the statement that "square roots only work for real, positive numbers". In particular, the problem with the "proof" above is in the third equality:

sqrt(-1)*sqrt(-1)=sqrt(-1*-1).

There is simply no way to define "sqrt" as any sort of square root function that makes this true.

As for your dispute, your friend is wrong. The statement

sqrt((-1)²) = sqrt(-1)

is false for all ways of defining "sqrt" as a square root function, since this says that sqrt(1) = sqrt(-1), while those two numbers (1 and -1) have no common square root.

The lesson to be learned from all this is that we don't get to apply supposed mathematical "rules" anywhere we want, but only where they do, in fact, apply. And rules that apply in certain special cases may not apply in general. In particular,

sqrt(a) × sqrt(b) = sqrt(a × b)

works fine when a and b are nonnegative real numbers. That's what we were all taught in school, and it is correct. However, this does not mean that this applies more generally to all pairs of complex numbers. In fact, it does not.

— Nowhither 01:10, 24 September 2005 (UTC)

None of the explainations here make sense to me. The part about the square root of a real number being defined as the positive root is true. The part about no nice way to fix this for complex numbers is not true. Square roots of negative numbers are defined as mapping to the set of imaginary numbers, thus 'i' is an imaginary number equal to square root of -1. Also, i*i is defined as equal to -1 because of this.

i is indeed a square root of -1, but so is -i, and (-i)*(-i) is also -1. You can't say that i is "equal to the square root of -1", because "the square root of -1" describes two numbers that are unequal. So how do you tell them apart? You can't say "take the positive one as the square root" like you do for real numbers, because neither i nor -i is positive. (Don't let the notation deceive you; remember that i and -i are perpendicular to being positive or negative.) RSpeer 05:17, 25 September 2005 (UTC)

• Look at it this way. In school we were taught that the rule "sqrt(a) × sqrt(b) = sqrt(a × b)" is correct for all positive real numbers. Maybe you missed the "positive real numbers" part, but, I can assure you, it was (or should have been) mentioned. Now, does this rule apply to complex numbers in general? No, as the original problem in this thread shows. It may seem intuitively true to you that this rule applies to anything with a square root. However, in mathematics, we do not base our notions of truth on intuition; we prove them to be true. Many properties of the complex numbers seem non-intuitive to people familiar only with the real numbers. This is perhaps one of them.

  And, regardless of whether it seems right, it is true that there is no nice way to define a square root function on all complex numbers. If you want to be formal, then substitute "continuous" for "nice".

  — Nowhither 17:47, 26 September 2005 (UTC)

5ht receptors

(no question asked)

Did you have a question? — Nowhither 01:11, 24 September 2005 (UTC)

Please review our article on Serotonin, and ask again if you need more detail.-gadfium 03:04, 24 September 2005 (UTC)

Codec hell

Well, I just got my computer and was trying to open a few video files, so I downloaded some codec packs. The first was ACE mega codec pack. It was great, opened tons of stuff, except this one divx video with some interleaving problem... Well, I removed ACE, and got a few other codec packs from free-codecs.com (k-like, xp and all in 1).

Installed all in 1 first. Didn't work. Uinstalled it. Installed XP. Didn't work. Uninstalled. Insalled k-like. It worked. But now WMP won't open the most basic video files (wmvs), and the automatic download of codecs feature returns an error (no appropriate codec could be found).

So, this sucks. Not even half of my videos are opening right now and I was wondering what I should do. Is there any tool that lets me remove ALL codecs from my computer, so I can get them all again? Is there any immediate problem on not having any codecs installed? Help! Kieff | Talk 01:30, 24 September 2005 (UTC)

Can't help with codec removal, but if you just want to play the videos, VLC player opens just about anything, and you don't have to mess with codecs.[4]--inks 20:24, 24 September 2005 (UTC)

You may be able to uninstall and reinstall Windows Media Player, or upgrade to a newer version, which will fix the codec problems. Rob Church ^{Talk | Desk} 21:14, 25 September 2005 (UTC)

Whilst I'm happy to recommend VLC player myself having used it these past couple of days, it doesn't seem to open the .wmv files I have.

Well, I managed to uninstall WMP and reinstall it. Things seem to be working now, thanks everyone. I'll avoid codec packs after this incident. Kieff | Talk 19:33, 26 September 2005 (UTC)

APPLICATIONS OF GRAPH THEORY TO COMPUTER SCIENCE

Sir,

Can you get me any three applications of graph theory to computer science" and what way it is used and details about that. Thank you. --anon. Question reformatted by Robert Merkel 08:53, 24 September 2005 (UTC)

Well, actually, I can, but I've done enough homework for one lifetime. Have you considered reading our article on graph theory, or perhaps your textbook? By the way, DON'T USE ALL CAPITALS BECAUSE IT'S INTERPRETED AS YELLING!--Robert Merkel 08:53, 24 September 2005 (UTC)

How temperature affect the atmosphere pressure?

Can you tell me how temperature affect the atmosphere pressure at an area?Is there any equation uses to calculate the atmosphere pressure of a place which related to the change in temperature?

• Yes there is. Try Combined gas law (and the related laws mentioned in the article. Atmospheric pressure may also be of interest to you. - Mgm|^(talk) 11:59, 24 September 2005 (UTC)

Alternative to the Big Bang theory

I've long had an alternative to the Big Bang theory, which surfaced when I gave an answer to Wikipedia:Reference desk/Science#A Variable Speed of Light hereabove. I'm very much a layman when it comes to this field, but I made a prediction that went against the accepted theories but turned out to be correct, which is a bit of a theoretician's wet dream :) . So I now venture to put this theory before you. Here goes.

As a kid I heard the expanding universe explained as a balloon with dots on it. On that everything moves away from everything else, which is exactly what we observe in the universe. But then I wondered, how do you know a balloon expands? My thought was that you know that because the only alternative is that the room you're in (and everything else) is getting smaller. Which would be silly. The simplest solution is held to be true, which is that the balloon expands. But for the universe there are (by definition) no surroundings to compare with. There is no reference frame, so one has to assume the size of of the universe is given. I couldn't think of a solution then.

But later I realised that you can also compare the sizes of the universe and everything in it. If the size of the universe is given then the stars and such must be getting smaller. Hmmm, stuck again.

Later still I imagined falling into a black hole. I was supposed to get stretched out. But that's seen from the framework of an outside observer. For me, I'm part of the spatial framework that gets expanded. Also, time gets ever slower form the perspective of the outside obeserver, but, again, I live in that timeframe, so from my perspective it will take me forever to fall into the black hole. So for me nothing changes (right?). Except that I see everything around me moving away from me. Hold on, I thought, couldn't that explain the aforementioned phenomenon? What if we are caught in a collapsing (part of the) universe? But then I realised that as things are further away they will accelerate away ever faster. And acceleration is not what happened, right? Stuck again.

Until a few years ago someone (Riess or Perlmutter?) discovered that exactly that is the case. When I heard of this I jumped out of my chair. After the initial enthusiasm I didn't know how to present this idea. No-one would take me seriously. Now, finally, I've found a place where knowledgeable people might be bothered to hear me out. So. Any thoughts on this?

By the way, I don't necessarily suggest we're falling into a black hole. I suppose being attracted to anything sizeable enough will have a similar effect. And since everything is attracted to everything else there might not have to be anything special going on. Though if it's that simple I find it unlikely no-one will have thought of this before. Or have they?

Also, as for the other two bases for the Big Bang theory, I don't have an explanation for the background radiation. The abundance of light elements suggests a fairly 'young' universe, which would still be possible if we're in the middle of the Big Crunch. DirkvdM 09:26, 24 September 2005 (UTC)

Hi DirkvdM. I know a reasonable amount of physics and will try to give a few comments. If we were in a collapsing part of the universe, then nearby galaxies would be moving toward us. This is only true of the Andromeda galaxy, and that is accounted for by the attraction of ordinary gravity. Everything else is moving away.

If we were falling into a region of extremely strong gravity, black hole or otherwise, that would be more clear from nearby conditions than from faraway objects.

It is also important to understand what is involved in the expansion of the universe. It is the actual expansion of the "fabric of space", rather than simply objects moving away through ordinary static flat space.

Let me know if that helps at all; I'm happy to discuss further here or on User talk:SCZenz. -- SCZenz 22:07, 29 September 2005 (UTC)

Yes, everything moves together when moving towards a common attractor (such as a black hole or 'everything itself' so to say – the Big Crunch idea). But that is from the perspective of an outside observer who doesn't take the distortion of the space/time fabric into account. But for those inside, space is stretched out more than that (the 'more' here is an assumption that is essential to my theory). Put differently, if I'm falling into the black hole (or whatever) I accelerate towards it. Anything that's ahead of me will have gained a higher acceleration and thus move away from me from my point of view (but is that accelerated? My gut says it is :) ). Likewise, anything that's behind me will do so too, but at a lower acceleration. Sideways this is a bit more complicated, but I believe a similar reasoning applies.

You say that the effects of falling into a black hole are more noticeable nearby than for things far away. But I assumed that the distortion of space/time counterbalances the acceleration. Or rather, there is no acceleration, just the distortion. An outside observer who superimposes his local frame on my situation observes an acceleration I don't perceive.

More in general, distortion is a misconception, because that assumes an absolute reference frame, which there isn't. What I perceive as distortion is really just the difference between my local distortion and the distortion of another place I observe. So to call the time/space there distorted is really a 'lococentric' (?) pov. DirkvdM 11:55, 30 September 2005 (UTC)

I am not an expert on this stuff either. My understanding is that there are several theories on the nature of the universe. One is that it starts with the Big Bang then after expanding to some size, it slows down the expansion, because of the gravity of the parts of the universe pulling at each other, and eventually begins to collapse again. So there's a bunch of theories whether it will expand forever, if it will collapse, or if only our part of the universe is expanding. Some of this has to do with hidden mass and studies of some patterns of energy.

Have you heard of quasars (spelling?)? These are humongous point sources of energy. One theory is that we are seeing the light from the original Big Bang which bounces off the edges of the universe, less and less frequently as the edges get further away, and by studying the pattern of quazars we can map the shape of the universe.

I would prefer to think that what quazars are, are the light from intelligent travelers traveling close to the speed of light, away from us (they are red shift quazars, which is all that can be seen by observers through our atmosphere. If there was blue shift astronomical bodies, we would not see them by astronomy on the planet. If we study the heavens from telescopes in orbit, then we might see a bunch of blue shift stuff, such as an intelligent visitor headed our way. However, I not think we looking for this. Telescopes in space are looking for stuff to expand the knowledge of terresterial astronomers who are already distorted view of looking through the rose colored glasses of our atmosphere, as opposed to starting over in study of our univers. AlMac|^(talk) 18:12, 29 September 2005 (UTC)

Why would the drive system of an alienship put out so much energy as to equal the light of a star? And why aren't any of them heading sideways, rather than directly away? -- SCZenz 22:07, 29 September 2005 (UTC)

When the alien ship is traveling close to the speed of light, its mass is close to infinite. This applies to the mass of all of it, including the ejecta of its propulsion system. They could be traveling in all directions. One flaw in my theorizing is the question of how long they would be blasting in some direction, relative to how long we see the red shift quazars through telescopes under our atmostphere. AlMac|^(talk) 01:08, 30 September 2005 (UTC)

armed forces transport

can you please tell me where i could find information on the modes of transport the armed forces use?

Are you interested in a specific country's armed forces, or armed forces in general?

If you're interested in a specific country, you might consider going to that country's page and using the military links from there; for instance, for the United States you'll probably browse from there to the Department of Defense page and then the pages for the individual services. From each of those, you might get a list of vehicles, for instance the United States Air Force link has a link to a page called List of military aircraft of the United States.

If you're interested in this topic in general, the United States is still probably a good area to explore, as the US military has logistics capabilities unrivalled by any other military force. --Robert Merkel 10:29, 24 September 2005 (UTC)

gravitation ????

Hello:

Why is it that only one side of the moon always faces earth? If you take an apple and rotate it around a lamp you'll find of you keep the axis facing the same direction all parts of the orange will be reflected as it revolves around the lamp. But the moon has to slowly rotate in such a way that it keeps its one side visible to the earth and as far I can tell it has been showing the same side of the moon for thousands of years? This can't possibly be a coincedence, but I don't see how Newtonian laws of gravity apply to this question.

Will Sperry Kunming China

Will: It's because of tidal forces and friction.

To begin with, do you understand why the ocean has tides? The Moon pulls a bit more on the water close to it, than it does on the Earth as a whole. So there is a bulge of water on the side of the Earth nearest the Moon. Similarly, the Moon pulls harder on the Earth as a whole than on the water far from it. So the Earth gets pulled away from the farthest ocean, resulting in another bulge of water on the side of the Earth opposite the Moon. And that is why we get high tides during the full & new Moon (or nearly so; the land gets in the way of water flow, which makes it all a good deal more complex).

Now, the Earth pulls the same way on the Moon, "trying" to create a bulge on the near & far sides if the Moon. This has two effects. First, if the Moon didn't always show the same face to the Earth, then as it rotated, it would get squashed in various directions. The resulting friction would turn part of its rotational energy into heat, thus slowing its rotation (relative to the Earth). Second, if the Moon is not a perfect sphere, it would have a tendency to settle in a position in which the bulge(s) faced either toward or away from the Earth.

And that is what happened. The Moon is not a perfect sphere, tidal friction slowed it's rotation, and it settled in a position in which the bulges are aligned toward/away from the Earth.

Of course, similar logic would suggest that the Earth should always present the same face toward the Moon. Why doesn't it? First, the Earth is bigger, so it has more angular momentum to keep it going. Second, the Moon is smaller, so there is less tidal force to slow the Earth down. But if we wait long enough, and no other factors intervene, and the Moon stays in its current orbit, etc. (which won't happen), then the Earth should eventually present the same face to the Moon all the time.

— Nowhither 11:21, 24 September 2005 (UTC)

Why would there be a specific bulge? (Maybe)Once upon time, millions of years ago, was the moon rotating around an axis and the earth's gravity finally slowed it down, to its current rotation? And why would friction effect the moon when it is in space where there is no friction? The tide analogy seems obvious because of the fluidity of water, but the solidity of the moon would seem to make a bulge less of a factor as the tides are effected by the moon. Over millions of years do these factors create slight changes that finally effect a final result?

Will Sperry Kunming China

Will, there is indeed friction in space; the laws of physics aren't somehow different in orbit around the earth. You're correct in that there's no air resistance (space being close enough to a vacuum for all practical purposes) but there is still internal friction within the moon. You can demonstrate friction inside solid objects be bending a paper clip back and forth until it breaks, and noting that the metal near the breaking point becomes warm. Similarly, friction within the moon's core can lower its kinetic energy. But yes, it seems plausible that the moon was at one point rotating at a different speed. --David Wahler (talk) 16:09, 24 September 2005 (UTC)

I thought this was a freak thing, caused by an uneven distribution of the matter inside the moon or a violent thing happening to the moon in its past, such as it tearing away from the Earth. The moon article states that the most accepted theory is that just that happened, caused by an impact by some third big object. However, the same section supports the above theory. But then this should also have happened to other moons. Is that the case? DirkvdM 19:04, 24 September 2005 (UTC)

DirkvdM: Yes, most of the known moons in the solar system are tidally locked. See Tidal locking. — Nowhither 19:57, 25 September 2005 (UTC)

It's called Tidal lock. The theory is, eventually every orbiting body becomes tidal locked to its parent body over time. Even the Earth to the Sun. - Cobra Ky (talk, contribs) 19:08, 24 September 2005 (UTC)

Drawing electrical circuits

Are there any freeware or shareware programs available for preparing diagrams of electrical circuits? I can't find any reference to them in the relevant articles. Physchim62 11:02, 24 September 2005 (UTC)

A search for "circuit" at Freshmeat.net turns up a number of packages. I haven't tried any of them myself (though I'm probably about to as an amateur PIC programmer). --Robert Merkel 12:19, 24 September 2005 (UTC)

Check this out at Wikisophia. Lots of other goodies there too which you might find useful. --HappyCamper 13:09, 24 September 2005 (UTC)

EAGLE is one I've used, which has the notable feature of being able to automatically lay out circuit boards for fabrication. (Not sure if that's something you need, but you might want to give it a look.) --David Wahler (talk) 15:57, 24 September 2005 (UTC)

There is a very good freeware called TKGate for Digital Cicuits Simulation and a very good GUI. In order to run tkgate on Windows, you will need to install Cygwin along with X11 and the X11 version of tcl/tk (as opposed to the native Windows version). For details see the Cygwin Cygwin Installation Page. As of TkGate 1.8.3, the configuration script now contains Cygwin specific code and should not require any modification.

However, for Analog Circuits, you can use Spice

Pause Break

On my QWERTY keyboard, what does the button "Pause/Break" do? --Dangherous 11:10, 24 September 2005 (UTC)

There is a brief explanation on IBM PC keyboard. These days, it's not used very much (except by gamers). --Robert Merkel 12:16, 24 September 2005 (UTC)

optical computing

What is optical computing? How does it work? What are its applications(please mention any brands or products already in use)?

Did you try reading our optical computer article? --Robert Merkel 12:09, 24 September 2005 (UTC)

md5 status?

What's the current status of the md5 hashing algorithm? There are numerous attacks noted against it, but would it be possible to easily explain what is possible and what not? And will sha-1 have the same problems soon? Thanks

Assuming you've read Md5#Practical effect of cryptanalysis and find it unclear, what it's saying is that it is possible and fairly easy to construct two different inputs which result in the same MD5 hash value – however the currently known methods for doing this do not generalize to finding a second input that results in the same hash value as an arbitrary given first input. MD5 is often used as a checksum to "guarantee" the validity of downloadable software files. This weakness does not mean it's easy for someone to generate an alternate version of an arbitrary downloadable with the same MD5 hash. What it does mean is that if I have full control over the downloadable file, I might be able to create two versions that have the same hash value. MD5 is also often used as a mechanism to store or transmit passwords. The MD5 article does not mention this, but modern processors are fast enough to compute the MD5 value for all possible, fairly short (8 characters or less), inputs which means if I can access the MD5 hash value for your password and you have a fairly short password, I can find out what your password is. This is one reason users are often told to use long passwords. There are some theoretical weaknesses in SHA-1, but no currently known method for "fairly easily" generating two different inputs with the same SHA-1 hash value. SHA-1 also takes long enough to compute that a brute force attack on passwords is only possible for shorter passwords. -- Rick Block (talk) 14:56, 24 September 2005 (UTC)

I agree, but I would elborate that SHA-1 has also been found to be weaker than desired, although not yet in the same "fairly easily" collidable way that MD5 has. Finding a collision for SHA-1 is believed to be within the capabilities of a massive distributed Internet search (ala Distributed.net). Because of this, cryptographers (who are a conservative bunch) suggest using a different hash function in new designs, although there's not that many obvious alternatives at present. The SHA-2 variants remain unbroken for the time being. (I would also argue that the difference in speed for computing hashes for SHA-1 and MD5 is small enough that it's not worth relying on it to give any significant advantage against dictionary attacks.) — Matt Crypto 18:58, 28 September 2005 (UTC)

How to produce endorphin

(no question)

1. Laugh.

2. Enjoy.

--Sum0 17:51, 24 September 2005 (UTC)

-2 Stick your hand in a bees' nest

-1 Whip yourself with nettles

0 run a marathon

Tonywalton  | Talk 00:48, 25 September 2005 (UTC)

Alternator wire

what is the maximun voltage drop allowed on an alternator wire on a vehicle
(added header to question – Mgm|^(talk) 14:22, 24 September 2005 (UTC))

I assume you mean "allowed by law". I imagine that would vary from country to country. You might want to indicate what country you are referring to? (In any case, I don't know the answer.) — Nowhither 20:01, 25 September 2005 (UTC)

Roentgenium's Color

If we could somehow produce enough Roentgenium to be visible to the naked eye (ignoring decay), what color would it be?

Probably silver-gray in colour. From its electron configuration, it will behave as a metal. With few exceptions, that's the colour that you get. TenOfAllTrades(talk) 17:33, 24 September 2005 (UTC)

Storage size

What is the storage size of a hard disk, Tape, CD-ROM,CD recordable and a DVD please can someone answer this one asap

Sounds like homework, but since it's so simple: with publicly available drives up to at least 2 TB (although this is an external drive), up to 800 GB, 650-700MB, 650-700MB, and 4.7GB (8.5 for a dual layer disc), respectively. For #3 and #4, larger variants DO exist, but they are fairly rare, and for #5, the capacity is twice as much for dual-sided discs. --Pidgeot (t) (c) (e) 17:28, 24 September 2005 (UTC)

It is related to the hardware ability to store & get at stuff in very small sizes (IBM has a quantum computer which records data at an atomic level, but this is still laboratory technology) and the addressing scheme. I think that 64-bit is pretty much the standard in what is economically available, but IBM reputedly has 128-bit in testing. AlMac|^(talk) 18:46, 24 September 2005 (UTC)

Who discovered the treatment of Malaria?

See malaria. — mendel ☎ 22:36, 24 September 2005 (UTC)

How much does 7 liters of gasoline weigh?

Could someone who remembers more of high school chemistry tell me how much 7 liters of liquid gasoline weighs? Either metric or imperial, doesn't matter. Thanks. --Brasswatchman 20:09, 24 September 2005 (UTC)

• Depends on the type of gasoline. Is it leaded or unleaded? High or low octane? Gasoline is usually a mixture of different components and the composition can differ per produced batch. I'm afraid giving a single answer is going to be quite difficult. - Mgm|^(talk) 20:19, 24 September 2005 (UTC)

• Our density article say gasoline's density is 0.73 g cm^-3. (I assume that's an average value, seems to match the value I got from a quick google). 7 litres is 7000 cm^3, so it would weigh 7000 * 0.73 = 5110 g or 5.11 kg. -- Bob Mellish 20:32, 24 September 2005 (UTC)

• I wasn't looking for anything exact, just average. Great. Thanks, both of you. Brasswatchman 9:53 PM EST, 24 September 2005.
  • Alternatively, just buy a gas can, weigh it, put 7 liters of gas in it, weigh it again, and check the difference... ;) I like to go for the easy way out. --Phroziac^(talk) 01:15, 29 September 2005 (UTC)

Stanis?aw Ulam

How is Ulam pronounced – You-lam or Uh-lam ? Tintin 20:54, 24 September 2005 (UTC)

I've always used the latter, but I can't say if that's correct or not... Shimgray 20:55, 24 September 2005 (UTC)

According to Polish language, it would be more like Oo-lam. Physchim62 21:06, 24 September 2005 (UTC)

Yes, Oo-lam. Stan-iss-wav Oo-lam. I don't know what that is in IPA. Proto t c 13:09, 26 September 2005 (UTC)

Help me begin understanding Prolog...

Since my professor doesn't seem to intend on replying to my e-mail (this is not a homework assignment, but I have to understand the basics of this silly language in less than 10 days before the first test), I'll throw this question to fellow Wikipedians, whom I hope some know Prolog.

Given this file:

line(2, 2, 4, 5).
line(1, 2, 4, 5).
line(1, 1, 4, 4).

linelen(line(X1, Y1, X2, Y2), Z) :- DX is (X2 – X1)**2, DY is (Y2 – Y1)**2, sqrt(DX + DY, Z).

I am able to do this:

?- linelen(line(1, 5, 3, 6), Z).

And get a valid result for Z. However, if I attempt pattern-matching:

?- linelen(line(A, B, C, D), Z). or ?- linelen(L, Z). It gives me ERROR: Arguments are not sufficiently instantiated. (I've also tried all sorts of other things, all of which give me this error -- this is the most basic, though, where I began trying to write this function).

Why is it not pattern-matching? I expected it to give me the lengths of each line that I declared as previous facts, but for some reason, it is not doing this. Is there something I'm not understanding right about how pattern matching works in Prolog? I think I understand it pretty fine, but it's the syntax that seems to be killing me. What would be the "correct" way to implement this function?

Also, could anyone recommend a really good book about Prolog? Our course textbook is the one written by Mr. Ivan Bratko, who I understand had a hand in standardizing Prolog, but unfortunately it's not really that good a textbook when it comes to explaining things clearly. A good example of a programming language manual that "clicks" with me is the one for Lua written by Roberto Ieruschamily(sp?) -- are there any Prolog books like that out there? --I am not good at running 00:22, 25 September 2005 (UTC)

It's been a while since I've worked with prolog, but I think your problem is that line(A, B, C, D) is returning false. Prolog only knows what you tell it, so if I for instance wrote a program:

related(marge, lisa).
related(marge, bart).
related(marge, selma).
related(snowball II, snowball III).

Then I'm simply telling it that all the above three statements are true. So if I input related(selma, bart), it'll return true while related(snowball II, lisa) will return false. Or if I input related(selma, Z), it'll return one of marge, lisa, or bart as Z.

So your first three lines are doing exactly what I did above, only nowhere in there is there A, B, C, D, so line(A, B, C, D) will always be false. What I think you want is to cut your entire program down to:

 linelen(X1, Y1, X2, Y2, Z) :- DX is (X2 - X1)**2, DY is (Y2 - Y1)**2, sqrt(DX + DY, Z).

Like I said, it's been a while, but hopefully that helps. — Laura Scudder | Talk 00:40, 25 September 2005 (UTC)

Awesome, that seems to work. I had to do this on the query line though: ?- line(A, B, C, D), linelen(A, B, C, D, Z).. I didn't know that query lines could contain comma-delimited multiple phrases (I thought only rules could) but it seems to work, in fact be required to get it working right. Thanks! --I am not good at running 01:21, 25 September 2005 (UTC)

I think the other way to do this would be to match one of the facts in your fact base before doing the arithmetic computation as part of the linelen definition, i.e. I think linelen could be:

linelen(line(X1, Y1, X2, Y2), Z) :- line(X1,Y1,X2,Y2), DX is (X2 – X1)**2, DY is (Y2 – Y1)**2, sqrt(DX + DY, Z).

The issue is the computations cannot be done on uninstantiated variables (could be if you defined your own version of the operators using facts from the factbase). The key is you have to make sure any variables you're doing arithmetic on are instantiated to actual values at some point before you try to do the arithmetic. I learned Prolog from the Clocksin and Mellish book (a long time ago). -- Rick Block (talk) 16:41, 25 September 2005 (UTC)

Hmm that approach seems to give neater-looking results when going for an entire series of defined line(etc, etc, etc, etc). facts, but it doesn't seem to be as flexible beyond that. I rewrote my linelen as per your example, but now it only seems to allow pre-defined lines, and answers "No." for arbitrary arguments. example:

?- linelen(A, Z).

A = line(2, 2, 4, 5)

Z = 3.60555 ;

A = line(1, 2, 4, 5)

Z = 4.24264 ;

A = line(1, 0, 4, 4)

Z = 5 ;

A = line(-5, 7, 1, 10)

Z = 6.7082 ;

A = line(10, 0, 39, 60)

Z = 66.6408 ;

No

?- linelen(line(2, 7, 320, -4), Z).

No

I definitely have a better understanding of how Prolog matches patterns now than I did two days ago, especially as to how it behaves when arguments are instantiated in the definition vs. being instantiated in the query lines before the actual function. Can't wait til I get around to tinkering with cuts and fails :) --I am not good at running 19:47, 25 September 2005 (UTC)

gravity

what is gravity, how does it act on mass. D Armstrong

The answer to these questions get quite complex and philosophical; see gravity for some discussion. There are two standard theories of gravity: Newton's law of universal gravitation, which for predictive purposes is almost always "close enough", and general relativity, which can provide predictive answers in those relatively few situations where Newton's laws give slightly incorrect answers. However, general relativity is incompatible with quantum mechanics, which is our model for understanding the other fundamental forces of the universe acting at a very small scale. Therefore, our understanding of the fundamental forces of the universe is incomplete; the models we have are incomplete approximations. So ultimately, we don't really know what gravity "really" is, but we have models that can predict what it will do. But what does it mean to know what gravity "is", anyway?

Aren't you glad you asked? --Robert Merkel 03:47, 25 September 2005 (UTC)

Also see Intelligent Falling :) -- Rick Block (talk) 04:27, 25 September 2005 (UTC)

how to handle demand of medical services

Find out what the United States is doing, and do the opposite...more seriously, if I'm understanding your question correctly you might be well served by starting with our (brief) article on heatlh economics health economics, health maintenance organization, managed care, and linked articles. No country is particularly effective at handling this problem; that is, unless you take the view that the ability to pay is the proper and only criterion for determining how medical treatment should be allocated. --Robert Merkel 12:10, 25 September 2005 (UTC)

military

i have to do a presentation on how to decrease cost of military?

Firstly, I'm assuming you're American. If you're not, recalibrate this advice to specifically search for items related to your country...anyway...

Do your own homework, but have you considered doing a Google search for, say, "defense budget waste" and seen what comes up? Tried a similar search on an electronic newspaper archive, if your educational institution has access to one? Oh, and just because I'm feeling super-generous, here's one big hint: missile defence... --Robert Merkel 04:03, 25 September 2005 (UTC)

Less wars. Ojw 10:41, 25 September 2005 (UTC)

That would be fewer wars or less war. Sorry :) DirkvdM 11:20, 27 September 2005 (UTC)

I suggest you read the 9/11 commission report, and similar reports from similar commissions (about 2 a year going back in history to infinity), especially about Congress doing a competent job on oversight and cut out the pork. AlMac|^(talk) 18:22, 29 September 2005 (UTC)

The percentage of GDP that goes into the military and national defense like internal security varies by nation. In the USA it was about 3% before 9/11, I suspect 4-5% now. One way to cut this down that hopefully will not happen, is to reduce it to zero, then pretty soon you no longer have a nation, because you been conquered, and now you spending 100% to the conquerors. AlMac|^(talk) 21:19, 30 September 2005 (UTC)

media

How to protect people from media?

You could lock them in a room with no televisions, radios, magazines, books, internet access, etc� Not sure why you would want to do this, though. Perhaps your question could use some clarification? Garrett Albright 10:30, 25 September 2005 (UTC)

multinational organization

How to hsndle problems created by big and large multinational organization?

• That depends entirely on the problem and the organization in question. Please be more specific. If you are unhappy with a product or service provided by a large organization, try writing a letter of complaint. - Mgm|^(talk) 07:49, 25 September 2005 (UTC)

Determinants

In my far younger days, when I was but a lad running through the meadows and marvelling at the glory of the morning dew, I briefly studied some matrix-theory. Alas, those days are long gone now, and what very little I learnt has mostly been passed into the forgotten lore-section of the library that is my memory.

Now, however, I'm going to need a little help with determinants, don't ask me why :P Our article Determinants is not totally clear on this issue (ie. it's probably perfectly clear and I'm an idiot, anyway I intend to clear it up a bit if I get a satisfactory answer here)

I remember this much: If you want the determinant of a 2d-matrix you go

${\begin{vmatrix}a&b\\c&d\end{vmatrix}}=ad-bc$

And for three dimensions you go:

${\begin{vmatrix}a&b&c\\d&e&f\\g&h&i\end{vmatrix}}=a{\begin{vmatrix}e&f\\h&i\end{vmatrix}}-b{\begin{vmatrix}d&f\\g&i\end{vmatrix}}+c{\begin{vmatrix}d&e\\g&h\end{vmatrix}}$

So far so good, right? My question is, does this extend to higher dimensions? That is, would the determinant of a 4d-matrix be:

${\begin{vmatrix}a&b&c&d\\e&f&g&h\\i&j&k&l\\m&n&o&p\end{vmatrix}}=a{\begin{vmatrix}f&g&h\\j&k&l\\n&o&p\end{vmatrix}}-b{\begin{vmatrix}e&g&h\\i&k&l\\m&o&p\end{vmatrix}}+c{\begin{vmatrix}e&f&h\\i&j&l\\m&n&p\end{vmatrix}}-d{\begin{vmatrix}e&f&g\\i&j&k\\m&n&o\end{vmatrix}}$

This seems fairly trivial, but i felt it would smart to ask. Ohh, and by the way, marvel at my l33t TeX sk11lz! gkhan 05:20, 25 September 2005 (UTC)

Very good, your evaluation of the determinant is correct. Remember that you can expand along any row or column as well as the first row. Enochlau 11:57, 25 September 2005 (UTC)

But mind the changes in sign! ${\begin{vmatrix}+&-&+&-&...\\-&+&-&+&...\\+&-&+&-&...\\-&+&-&+&...\\...&...&...&...&...\end{vmatrix}}$ --R.Koot 19:11, 25 September 2005 (UTC)

gkhan: You should know that determinants, while being a useful theoretical tool, essentially never need to be computed. If you are simply curious about this, then that's fine. If you are interested in learning about how determinants fit into matrix theory, no problem. But if you have some practical computation for which you think you need to compute the determinant of a large matrix, then I would advise you that there are probably better ways to do your computation. — Nowhither 20:08, 25 September 2005 (UTC)

Yes, I realise that :P I'm simply curious, if I ever need to compute it, I'll use Mathematica :P gkhan 22:13, 25 September 2005 (UTC)

Places where the pressure change most obvious in one day

Is there any place where the atmosphere pressure at that place would change very obvious in a day?Could it be beaches?

The most atmopsheric pressure changes during a short period of time is when a strong tropical cyclone is approaching, preferably at a high rate of speed. For example, atmospheric pressure bottomed out in hurricane Rita at 917 mb I believe while the worldwide average is 1014 mb. -Drdisque 06:12, 25 September 2005 (UTC)

• Do aeroplanes count? BTW, I heard a figure for 897 mbar for the minimum of Rita: the standard atmospheric pressure is 1013.25 mbar. Physchim62 10:05, 25 September 2005 (UTC)

FYI, and just to clarify, a mbar / mb is short for Millibar, where a bar is 100 kilopascals. So a millibar is 0.1 kPa or 1 hectopascal.

Information Technology Spending Patterns by Activity Sector

Hello,

As part of my Executive MBA Programme, I am examiniing Information Technology Spending Patterns by Activity Sector.

Would anybody have any sources, articles that have looked at this question in detail? I am particularly interested in the Finance, Retail and Manaufacturing Industries and in the Europe, Middle East and African region,

Thanks

Seanjoseph

--Seanjoseph 10:28, 25 September 2005 (UTC)

1. Do a Google Search for "Research" and you will find tons of organizations that do different kinds of research, publish research reports, some of them available on-line. Google also has numerous competitor search engines, some of which are better suited to some kinds of searches.
2. Visit each of the groups, such as Gartner Forrester many many others, and at each one use THEIR search engine, or Google limited to their domain, to find research they have already done in the areas that interest you, and which are available to you for free, Review the abstracts of those research reports to see if any of them meet your needs.
3. If not yet successful, change the search to include those that you can purchase, for sums like $50.00, $250.00, thousands of dollars.
   1. For example, here is a link to a 4 page report which you can download for $ 250.00 from Forrester Research How Italian Consumers use Banking Channels which was just published Sep 23 of this year.
   2. At that kind of pricing, and your broad range of permutations that you need data on, you need to get as much as you can from the free sources.

AlMac|^(talk) 18:28, 29 September 2005 (UTC)

Dr. Salam's Nobel Prize

what was the theory of Dr. Salam, for which he was awarded Nobel Prize in 1979 ?

See Nobel Prize in Physics. The prize was given "for their contributions to the theory of the unified weak and electromagnetic interaction between elementary particles, including, inter alia, the prediction of the weak neutral current", so it looks like he was one of the co-creators of the electroweak theory. Our article on that isn't very helpful, though... Shimgray 11:45, 25 September 2005 (UTC)

In a nutshell, he unified the theory for the symmetries which govern charged particles and those particles which suffer radioactive decay. Ancheta Wis 11:20, 1 October 2005 (UTC)

Hurricanes – how are the formed and where?

How are hurricanes formed, and where do they begin? Apart fro the western US do other arts opf the world get hurricanes? e.g. S. America, Europe, Africa, Asia? Signed Sarah B

• Geography of Cape Verde <--try this one and also Cape Verde-type hurricane--205.188.117.71 04:05, 29 September 2005 (UTC)

• See Hurricane. --jpgordon∇∆∇∆ 15:02, 25 September 2005 (UTC)
• Our Tropical cyclone article is worth a look too as that is what they are called in northern Australia. Capitalistroadster

question plz

can you tell me how water can be purified by sand gravel and pebbles or can it be only purified by sand and gravel, not pebbles. plz answer me back as soon as possible. i need to give as much information as i can to my teacher tomorrow</math>

• Just pebbles isn't enough. They will only filter out the biggest things out. Our article on Water purification may be of use to you. - Mgm|^(talk) 20:01, 25 September 2005 (UTC)

Breath Waste products

What two waste products are contained in your breath?

• Is this, by any chance, a homework question? Notinasnaid 19:26, 25 September 2005 (UTC)
• I'm by no means an expert on anything biological so don't take my word for this, but sometimes the tonsils (or whatever those two holes in the back of your throat are) will develop thick gobs of pus -- white blood cells, I think -- causing a really horrible odor in your breath. I usually get this when I have a cold and sore throat. I wouldn't be surprised if this were one of them, considering it's gross as hell like you'd expect from a "waste product", so look into that and see if it's true --I am not good at running
• Don't forget good ol' Carbon Dioxide.--inks 20:47, 25 September 2005 (UTC)
• air – oxygen = carbon dioxide + nitrogen. --R.Koot 21:01, 25 September 2005 (UTC)

education

demographic educational levels in spain?

You might be interested in our article Demographics of Spain.  --  W  P Talk 06:01, 28 September 2005 (UTC)

If you go to the CIA World Fact Book, it has by nation, things like literacy rates for men, women, other subdivisions relevant to that nation. AlMac|^(talk) 21:21, 30 September 2005 (UTC)

Iron Supplements & Dental Caries

Does Supplementary Iron drops in childrens cause dental caries? ---~~|

As a molecular-biologist-in-training, I would be surprised if they did. Have you tried searching with those terms on Pubmed? [5] --inks 02:18, 26 September 2005 (UTC)

The Color Spectrum

When was the Optical Color Spectrum founded? Who dicovered the wavelengths and in what year did the factual evidence occur?

Isaac Newton discovered the spectrum (I belive he discovered it in his anno mirabilis, 1666), although he thought light was made of particles (which it turns out it kinda is, and well, kinda isn't). The first to surmise that light was made from wavelengths I'm pretty sure was Thomas Young using his double-slit experiment in 1801. By the way, that experiment, it's ridiculusly cool. What do you mean by factual evidence? Both Newton and Young had factual evidence (Newton saw the spectrum, Young saw the wave-interference). For more info, see Optical spectrum gkhan 03:27, 26 September 2005 (UTC)

Well, Newton recognised the spectrum for what it was. After all, the spectrum is shown in things like the rainbow, so the first person to notice that is lost in the mists of time. --Fangz 12:49, 26 September 2005 (UTC)

Noticing the colours of the rainbow is not the same as realising that they're constituent parts of white light. And the first person (as far as is known, I must admit) was not Newton but Roger Bacon, in the 13th century. That's 4 centuries before Newton! This guy was way ahead of his time in many fields and deserves to be just as well known as Newton, Aristotle, Galilei and the like. He could be seen as the first modern scientist, although he did dabble in stuff like alchemy as well, but then that was the chemistry of the day, so to say. DirkvdM 11:28, 27 September 2005 (UTC)

How many fault lines are there

A whole bunch. Each boundary lines is a geologic fault, but according to the article, there are a whole mess of faults that are nowhere near any tectonic plate-boundaries. gkhan 03:34, 26 September 2005 (UTC)

Gravity and its effect on the human body

Hi Science Wizards; My question is ,does Gravity have any measurable effects on the human body and if so how are these effects measured ? Does gravity effect the body different at night then during the day ? Are its effects different if we are standing or lying down?

                                    Thank you , this site is great ,Sincerely Dennis NIgrelli

Gravity has many effects on the human body. Off the top of my head, I can think of how the fluid pressure in the feet is higher than in the head when you're standing, thus the need to elevate the feet for many medical problems. Another issue is that gravity causes the pressure and stresses in you're skeletal system. I know of at least one bio-engineering researcher studying how to grow artificial menisci who has discovered that to grow them properly, you need to simulate the force on them that would be present in a growing child. You might be interested in the sorts of medical experiments that NASA has performed on its astronauts on how low-gravity environments affect the body, sometimes called space medicine. — Laura Scudder | Talk 04:02, 26 September 2005 (UTC)

(added after Edit conflict, so I might be parroting a little) Does gravity have any effect on the human bodies? Throw yourself off a skyscraper and check ;). That is, earth has a very big effect on the human bodies, it keeps us on the ground. Prolonged abscence of gravity is very harmful for the human body, your bones start to degrade almost instantly. Thats why astronauts has to be carried off their shuttles. Night and day or standing or lying down has no effect, the only thing that affets gravity is mass of the two objects (in this case, your bodymass and the mass of the earth) and distance to center of gravity (=center of earth). There is however a noticable difference in weight (note:weight, not mass) is if you are closer to the equator. At the equator, you are farther from the center of the earth (since earth isn't a perfect sphere) and you are influenced by the centrifugal force of the rotating earth. I've heard that it's a few Newtons difference from Sweden where I live (which would translate to a few hundred grams). gkhan 04:08, 26 September 2005 (UTC)

In case you are not enrolled in a space program, I've heard (although couldn't find it in Wikipedia, so it could be urban myth) that your spinal disks compress during the day due to gravity, so that at the end of the day you are a couple of centimetres shorter than you are after a nights rest (when you are horizontal your disks can expand). --Commander Keane 06:41, 26 September 2005 (UTC)

Another aspect of gravity affecting the human body is its effect on those subject to high-G, for example fighter pilots. A high-G turn can cause the pilot to lose vision and eventually consciousness. They wear special suits, G-suits, to help protect against it. Which brings me to the other point. There is no difference between the effect of G at night or day, but it does make a difference if you are lying down or not. You are less prone to blackout if you are lying down. DJ Clayworth 17:08, 26 September 2005 (UTC)

Heat suits and ambient vs. radiant heat

This crazy moon-man suit protects the wearer from 1500�F ambient heat and 2000�F radiant heat. This less-crazy moon-man suit still maintains 2000�F radiant heat, but only 200�F ambient. What do they mean by "ambient" and "radiant" heat? What sort of things would one need a 2000�F/200�F suit for? I read over Heat and Thermal radiation and understand what thermal radiation is, but I can't figure it out in terms of those suits. (Not that I need to know for any practical reason, but it's bugging me that it's not obvious to me.) — mendel ☎ 04:46, 26 September 2005 (UTC)

As I understand it, ambient heat is the temperature of air in a location, and radiant heat is the temperature to which a solid body in that location would be raised to by the thermal radiation. You can reflect thermal radiation, but you can't "reflect" the ambient temperature, so it's not surprising that it's much easier to protect against radiant than ambient heat. --Robert Merkel 05:47, 26 September 2005 (UTC)

Oh, and this page on that website says pretty much the same thing I just did. --Robert Merkel 05:50, 26 September 2005 (UTC)

I must have read right past that section, thanks. I'm now thinking about "1500� in the shade!" — mendel ☎ 19:16, 26 September 2005 (UTC)

Computer Safety – list of free mp3s

Through a site I trust (a wiki no less!) I discovered something called Webjay which appears, according to its newbie FAQ, to offer playlists of free mp3s compiled by users who simply link directly to external legal mp3 files, (eg this playlist of tracks John Peel is supposed to have played).

I've never previously been scared of mp3 files. As far as my knowledge goes, mp3 files are not a security risk to my machine. But, I suppose this just seems a little too good to be true ;o) My question is, simply, is it safe?

Whilst I'm here, what do Wikipedian Windows users use for anti-virus software? I have always used Norton, but due to some of the ways I've been using my machine lately I've come to share the seemingly prevalent view that Norton slows down your system. --bodnotbod 06:24, 26 September 2005 (UTC)

The corporate versions of Symantec anti-virus are less resource-hungry than the consumer versions. I don't know why. I run Symantec Client Security on my Windows machines. I don't know if a consumer can buy it – I got it for free from work before I left. I've heard AVG is quite reasonable and it's free for non-commercial use.-gadfium 06:47, 26 September 2005 (UTC)

I would be very surprised if a .mp3 or .m3u file posed a security risk in itself (of course, you can rename any file to a .mp3/m3u). ATM, I don't run any anti-virus software, and have not for a few years. Then again, I don't use MS Outlook either :)--inks 10:49, 26 September 2005 (UTC)

I recall hearing about some programs that had a security error with ID3 tags, allowing a buffer overflow. I don't believe it's a threat if you use an updated player, though, like Winamp 5.10.

As for anti-virus, AVG is a very good program. Not to mention free. ^_~ --Pidgeot (t) (c) (e) 11:08, 26 September 2005 (UTC)

• At the moment I run a free version of AVG anti virus. - Mgm|^(talk) 08:06, 26 September 2005 (UTC)
  • At home I run AVG free on my laptop and AVG paid-for on my main PC. The main benefit of the paid-for version is the customisability (if there is such a word) of the tests and test/update scheduling. Unless you want to fiddle with settings and the like then the free version is more than adequate. Thryduulf 14:24, 26 September 2005 (UTC)
    • Well, that's quite a vote of confidence in AVG. I too am pretty good, I believe, in terms of surfing safely and did manage not to get any nasties for years without running any guard at all. The only thing that's stopping me dumping Norton immediately is that – if I recall correctly – I only PAID to renew my subscription about 4 months ago. But I've already lost the money and there's no point being a damn fool about using a slowed computer unnecessarily, I suppose. --bodnotbod 01:32, 27 September 2005 (UTC)

Hurricanes

Dear Sirs,

I am currious to know if the water picked up over the ocean by a hurricane and is later dropped over land, is salt water or fresh water when it hits the ground? How does the hurricane suck the water up and if the rain droped is fresh, where does the salt go? Does the salt stay in the Ocean because it is too heavy or does it evaporate during the picking up of the moisture process? --[User:24.58.206.102|24.58.206.102]] 14:02, 26 September 2005 (UTC)

First, please do not indent text by pleaving blanks at the start of paragraphs on wikipedia. it formats your text as mon-spaced, unwrpped, which is good for a few special purposes, but not for ordinary text.

Secxond, the water evaporates from the ocean surface and joins the hurricane as water vapor. This leaves the salt (and anything else dissolved) behind. Thus any rain is fresh water. DES ^(talk) 14:13, 26 September 2005 (UTC)

I believe it's just tornadoes that suck up thing. Right? DirkvdM 11:51, 27 September 2005 (UTC)

Rubbish, not everyone believes in water vapor, molar heat capacaties are just the work of evolutionsits and other unsavory types (; trying to force their damn theories on everyone, I like my globe flat, and pancake like, not all spherical like *some* people want it

In USA all you have to worry about with what "sucks up" is tornadoes and man made out of control. Elsewhere in world are water spouts that behave something like tornadoes except are over water.

Also a lot of the water that ends up on the ground in the aftermath of the Hurricane, did not come from the sky, but from the surface, either via storm surge, or flood control breakage. [User:AlMac|AlMac]]|^(talk) 18:40, 29 September 2005 (UTC)

Computers Solving Mathamatical Problems

Do mathamagicians accept that computers can solve very complex problems?

for example. The four colour map theory has been solved by computers for a massive ammounts of polygons. However, many people still say that it has never been solved as a computer did it.

I dont get it! Please help

While it has been proven, many mathematicians find an exhaustive search so unelagant they don't want to call the verification of all posibilities a proof. One very good reason is that such a search does not give provide a deeper insight in why this it is true, which is often considered more important than the fact that it is true (see four color theorem). Also, most problems cannot be solved in this way, because an infinite number of cases have to be tested, or an amount simply too large. For example, the weak goldbach conjecture. Also if we would be able to lower this bound so that we could do a computer search, this would be rather pointless as the conjecture is of no practical use and a computer search would provide no intellectual challence. --R.Koot 14:22, 26 September 2005 (UTC)

The various computer-assisted proofs of the four color theorem are examples of a method of mathematical proof called proof by exhaustion. A computer-assisted proof by exhaustion involves the following steps:

1. Show that a problem can be reduced to solving a finite (although possibly very large) number of special cases
2. Devise a method of solving any one of these special cases through a finite (though again possibly very large) number of calculations
3. Write a computer program to apply this method to each of the special cases, with cross-checks to detect mistakes in design or programming or run-time errors
4. Run the program
5. Publish the program, the results and an explanation of the method in an accessible form.

Only step 4 is actually carried out by the computer. The reservations that some mathematicians might have about such proofs are more to do with the difficulty of completely validating any long and complex proof, and the lack of insight inherent in the proof by exhaustion method, rather than the fact that a computer has been used. Gandalf61 14:44, 26 September 2005 (UTC)

Original poster: You have perhaps been reading some out-of-date information.

It is true that we are not very happy with large computer-based proofs, because they are not very elegant and they give us little insight into what is really going on. Further, they force us to base notions of absolute truth on whether some particular electronic circuits were functioning properly.

However, the most important problem with the mid-1970s Appel-Haken-Koch proof of the Four Color Theorem is that no one has ever checked it independently. A group of researchers (Robertson, Sanders, Semour, Thomas) decided to do the checking in the early 1990s. They eventually found it easier to produce their own computer-aided proof, which followed similar lines, although it was a bit simpler. This proof has been checked independently. Further, you can download their program and run it yourself.

So now we can be quite confident that we do have a proof of the Four Color Theorem. And mainstream mathematical culture generally accepts computer-aided proofs these days. Although we still prefer traditional proofs, for the reasons of elegance and insight that I mentioned above.

— Nowhither 18:04, 26 September 2005 (UTC)

Just as a sidelight, computers can still be useful for numeric methods of calculation. For instance, there exists a class of mathematical functions which an integral exists, but cannot be found. A computer can approximate the value of such an integral using numeric methods when traditional mathematical methods cannot.

what is the freezing temperature of alcohol?

Does alcohol freeze as how water would freeze? If so what temperature does it freeze at?

There are many different kinds of alcohol, and they all have lower freezing (and boiling) points compared to water, which freezes at 0�C, or 32 F. The one you're probably thinking of is ethanol, which is the alcohol in alcoholic drinks. In normal atmospheric conditions, ethanol freezes, in much the same manner as water, at -114.3 �C, or -173.74 F. Proto t c 15:08, 26 September 2005 (UTC)

A minor nitpick...the low molecular weight alcohols freeze and boil at much lower temperatures than water; the longer chain ones freeze and boil and higher temperatures. Methanol (one carbon), ethanol (two carbons), isopropanol (rubbing alcohol, three carbons) are short chain alcohols. By the time you get out to dodecanol (also called lauryl alcohol) you're up to twelve carbons, and the stuff freezes and boils at 24�C and 260�C, respectively. TenOfAllTrades(talk) 16:16, 26 September 2005 (UTC)

Alcohol is also hydroscopic (i think that's the term), which means it attracts water. Normal rubbing alcohol has 30% water in it. When they make "moonshine" (ethanol), the still is used to boil the alcohol off the water, which boils at a much lower temperature. Anyway, having an amount of water in will raise the freezing point. --Phroziac^(talk) 01:10, 29 September 2005 (UTC)

Andrew C. von Eschenbach

What is his biography?

See Andrew von Eschenbach. TenOfAllTrades(talk) 16:06, 26 September 2005 (UTC)

Computer storage media

What are 5 different storage medias with their descriptions, capacity levels, advantages, and disadvantages? Where did you get this information? --63.199.33.66 16:40, 26 September 2005 (UTC)

Please refer to the instructions at the top of the page, and note that Wikipedia is not here to do your homework for you. I would recommend starting at our article on data storage devices, and working from there to find the information that you need. TenOfAllTrades(talk) 16:51, 26 September 2005 (UTC)

DYOH, but a similar question was answered above at #Storage size. Garrett Albright 19:21, 26 September 2005 (UTC)

I dont think its homework... Would you classify a extra credit project "Homework"?

Of course. I already did my time in the public school system and four years of university. I've done my share of schoolwork, and I'm really not interested in doing any more anytime soon, and especially not someone else's. Garrett Albright 18:51, 29 September 2005 (UTC)

diseases?

what is the difference between a communicable disease and a pathogenic disease?

• Pathogenic diseases are caused by pathogens (outside sources) while communicable diseases are diseases that can be transmitted between individuals. Most diseases that are communicable are caused by pathogens, but not all pathogenic diseases can be transmitted.- Mgm|^(talk) 22:06, 26 September 2005 (UTC)

Next round of the endless Moth Identification Game

My friend is keen to have this moth (right) identified, which he describes as "huge". Any takers?

I'm suffering from an identity chrysalis

--bodnotbod 18:57, 26 September 2005 (UTC)

Isn't this an Owl butterfly? Rmhermen 13:46, 27 September 2005 (UTC)

Well, it's a world I know nothing about, much less the subtleties – but on a quick look at the link it would certainly seem to match. I'll pass that on, thank you. --bodnotbod 17:50, 27 September 2005 (UTC)

orcas

Hi. Are the Orcas in the fiords of Norway there yet? Thanks.

permutation cipher

• See Permutation cipher. - Mgm|^(talk) 22:08, 26 September 2005 (UTC)

What is the purpose in standards of wiring?

The subject pretty much sums up the question.

Why do you ask? You see, the way you ask it makes it sound a bit like a homework question. Notinasnaid 19:53, 26 September 2005 (UTC)

Standards (such as AWG-American wire gauge) save money, reduce effort, and create repeatable results. Ancheta Wis 11:28, 1 October 2005 (UTC)

You also might be interested in knowing about standards for the manufacturing of wiring. AlMac|^(talk) 04:01, 3 October 2005 (UTC)

what is dual axle white balance

I'm assuming you meand "dual axis". Color temperature provides a hint: "Color temperature" is sometimes used loosely to mean "white balance" or "white point". Notice that color temperature has only one degree of freedom, whereas white balance has two (R-Y and B-Y).. So I'd guess (never having seen the expression before, and only coming up with a single Google hit) that simpler cameras use a one-dimensional adjustment (color temperature), calling it "white balance"; while fancier ones (like the Canon EOS series, the only context in which Google found something) have a two-dimensional adjustment. --jpgordon∇∆∇∆ 22:22, 26 September 2005 (UTC)

Space

How did the space program come to in the US after world war 2? -jody

• Perhaps our NASA article can help you find some answers. - Mgm|^(talk) 22:11, 26 September 2005 (UTC)
• The program to get German rocket scientists (and, indeed, rockets) out of Germany was known as Operation Paperclip. Shimgray | talk | 23:28, 26 September 2005 (UTC)

Ironically, you could say that the USSR got the space program into the USA. Werner von Braun was brought to the USA to work on nuclear missiles (since he had designed the V2). He really wanted to work on space rockets, but only after the USSR went to space did politicians start listening to him. DirkvdM 12:00, 27 September 2005 (UTC)

Traditionally, until sputnik, the US space program was hopelessly underfunded, then sputnik was a shock to the US psyche, much like Hurricane Katrina is a recent shock leading to a renewed effort to do a competent job managing infrastructure and disaster avoidance. After the US Space Program got to the Moon, US public support for funding evaporated, and NASA got kind of Lost in Space. AlMac|^(talk) 18:50, 29 September 2005 (UTC)

See space race. Ancheta Wis 11:32, 1 October 2005 (UTC)

Chemistry

Dear Chemists:

I need to know exactly how much HCL acid and distilled water to combine to arrive at a liter of 1.5M solution of dilute HCL acid. Note: I am using 31.45% Muriatic acid for this project. If possible, please tell me how you arrive at the answer.

Thank you in advance! Docfrickey

I should point out that you'll never be more than premedfrickey, if you really need wiki to do your general chem homework--205.188.117.71 03:59, 29 September 2005 (UTC)

Let me try. From Hydrochloric Acid (which is Muriatic acid by a different name), we know that HCL is 36.46 g/mol. For 1L containing 1.5M, you need 36.45*1.5=54.675g. A 31.45% solution of HCL has 31.45g (or 0.86 mol) of HCL/100ml, so you need 1.5/0.86*100ml=174ml of 31.45% HCL solution. Make up to 1L with 826 ml of distilled water. Can someone else check my numbers? I was never very good at this :) --inks 23:18, 26 September 2005 (UTC)

These values of 174 ml of 31.45% HCl and 826 ml distilled water are correct. You get a solution of exactly 1.5M.Borbrav 05:48, 27 September 2005 (UTC)

To be precise, you should use 174 ml of 31.45% HCl, and then add enough water to make 1000 ml of solution. The water you need to add might not be 826 ml, because there's no guarantee that volume is conserved when mixing liquids. Chuck 22:44, 27 September 2005 (UTC)

• Docfrickey,

I have removed your e-mail address. The response isn't by e-mail and keeping it in such a high-traffic site means you will receive plenty of Spam and Phishing attempts. Capitalistroadster 05:59, 27 September 2005 (UTC)

Muriatic Acid contains Zinc Chloride, I hope this does not mess up the experiment.

I can find no indication that Muriatic Acid is HCL + Zinc Chloride. Everything I've found so far says it's an old name for Hydrochloric Acid. I would venture that if there is ZnCl in your HCL solution, unless told otherwise you should assume there are trace quantities only, and ignore it with regards to your calculations. Also, tell your chemistry teacher (or lecturer) to stop using outdated terminology! :)--inks 21:44, 27 September 2005 (UTC)

You would never do it this way for at least three reasons:

1. 31.45% Hydrochloric acid is corrosive and so it is difficult to measure an accurate volume.
2. Solutions of hydrochloric acid at that concentration tend to lose hydrogen chloride gas to the atmosphere, so you cannot be sure of the exact concentration.
3. Volume measurements are intrinsically inaccurate (0.1% accuracy at best), so the calculated concentration would not be sufficiently precise for further high precision work

Message to your teacher ('cos this sound like a homework question): think up more realistic situations for your students' exercises! Physchim62 14:59, 28 September 2005 (UTC)

No. Point 1: Corrosivity hardly affects measurement especially in glass instruments; Point 2: Yes it does off-gas, but it is hardly significant. In fact, these concentrations are standard laboratory stock; Point 3: Volume measurements are accurate and precise enough for a wide variety of applications. Rmhermen 03:36, 29 September 2005 (UTC)

Point 1: Of course corrosive liquids can be measured in glass apparatus if you know what you're doing (I can remember pipetting bromine as a postdoc), but it is not recommended if there are alternative solutions (as here); Point 2: Standard lab stock is 35–37%, you would be a fool to trust a concentration given to four significant figures; Point 3: True, but you would never prepare either a standard solution (ie precise concentration) or a reagent solution (imprecise concentration) by the method that the questioner requests.

For reagent 2M hydrochloric acid, add 200 mL conc. hydrochloric acid to 800 mL water. For standard 0.1M hydrochloric acid, start with the reagent diluted acid as prepared above, titrate it against sodium carbonate using methyl orange as the indicator, dilute it appropriately and retitrate the diluted solution to obtain the precise concentration. Physchim62 07:40, 29 September 2005 (UTC)

how much water does asparagus use

How much water does Asparagus use to grow? To cook? To wash his car with? Our article on Asparagus has links at the bottom to websites describing how to grow and cook it, and hopefully one of them contains what you want to know :) --inks 00:35, 27 September 2005 (UTC)

mission critical

Wht does mission critical mean?

It denotes something (or even someone) that is of crucial importance to a particular objective, or mission. Very generally, without a mission critical item, the mission cannot proceed or be completed.--inks 00:44, 27 September 2005 (UTC)

1. Think of the infrastructure that is essential to some mission or objective. If the Infrastructure fails, then the objective fails. Examples:
   1. In the aftermath of Hurricane Katrina many hospitals lost electricity, telephones, ability to be resupplied by ambulances, did not get fast enough helicopter service, so they were not able to keep all the patients alive. In this sense we can say that some of the infrastructure of the hospital was mission critical to the patients who were in dire straits.
   2. Think of the role of computerized recordkeeping to the notion of business continuity. If the computer gets trashed, if the backups are ruined, then perhaps the business cannot continue operating. Thus a system, for keeping backups out of harms way, is said to be critical to the mission of keeping the business continuing.

AlMac|^(talk) 18:55, 29 September 2005 (UTC)

What is this insect?

red & black bugs eating daisies in the desert

Long time answerer, first time asker: What is this insect? The photo is from Anza Borrego Desert State Park near San Diego, CA.

Thanks, --Joel 02:34, 27 September 2005 (UTC)

Do insects eat while copulating? :) DirkvdM 12:04, 27 September 2005 (UTC)

Sure, they use their short lifetime very efficiently, and so would I if I thought I could get away with it. Shantavira 17:06, 28 September 2005 (UTC)

I can add more photos if that would help, but I'm still curious as to what these things are.--Joel 16:07, 29 September 2005 (UTC)

Lightning?

What is lightning?

Have you seen our article about Lightning? It has some wonderful photos, and explains the phenomenon well.--inks 05:47, 27 September 2005 (UTC)

records management.what is a record?it's life cycle& why do organisation maintain records?

Our Records management article should provide some assistance. Capitalistroadster 09:22, 27 September 2005 (UTC)

Do you personally pay any kind of taxes? Do you keep any records so that you can correctly calculate them and prove what you owe in case you get audited? Companies are even more interested in making sure they do not get over-taxed. AlMac|^(talk) 01:11, 30 September 2005 (UTC)

Quantum Decoherence

What does quantum decoherence means? I know its the collapse of the wave function, but what exactly is it. Can anyone exlain it in a simple, conventional way without using much maths?

FireFox Bookmarks Directory

Where is the directory path in which favorite sites are bookmarked in Firefox Mozilla browser?

For 2000/XP, look in C:\Documents and Settings\<Windows username>\Application Data\Mozilla\Firefox\Profiles\default.7pr, assuming you aren't running with multiple profiles. --Pidgeot (t) (c) (e) 11:34, 27 September 2005 (UTC)

A simplified version of the above is

%AppData%\Mozilla\Firefox\Profiles

You can't paste the "default.7pr" because the extension varies by installation. However, you go into the default folder and grab bookmarks.html

algorithms

• see Algorithm. Capitalistroadster 03:57, 28 September 2005 (UTC)

How to clean up acid spill?

Depends upon how much acid, also depends upon what kind of acid. Small spills can be cleaned up via adding a base, or alkaline substance found around the home. Typical substances are Sodium bicarbonate, ammonia and lye. Sodium bicarbonate will froth profusely in contact with acid, ammonia can be toxic in large concentrations so make sure you have plenty of ventelation, lye will burn the skin if left in contact for a prolonged period so make sure you wash it off or even wash with a solution of vinegar. Some acids, like prussic acid are deadly poison so get out of the area fast, others like acetic acid found in vinegar are not very dangerous, so washing with water would be good enough. Large spills often are taken care of by nature herself as carbonates in the soil react and neutralize the acid.

Still a lot depends upon the acid, how much and where the spill was.

If your worksite is in OSHA's jurisdiction and keeps big jars of acid around, it should have a "spill kit" with thick rubber gloves and a box of deluxe cat litter, which both absorbs and neutralizes. The absorbent they use for chemical spills often has a pH indicator in it, so that it turns from pink to blue when you've used "enough" (subject to the manufacturer's judgment, this might be "more than a reasonable person would use in any circumstance"...). Plain cat litter will work just as well, if you use common sense and don't get out the broom until the acid is completely soaked up.

I also aggree with the earlier editor that it matters what type of acid (LSD, for instance, is another matter entirely), but also what concentration: if you have spilled a large ammount of glacial acetic acid, you might have trouble breathing in that room until the cleanup is done, so it might be wise to call someone with a respirator and the training to use it properly.--Joel 22:21, 27 September 2005 (UTC)

platform

er...platform lists quite a few subjects, from shoes to weapons, cars to politics, oil, tectonics, computers, and railways. Read through it until you find what you're looking for, or come back with a more thorough question. Or try wiktionary:Platform if your command of the English language is the problem.--Joel 22:35, 27 September 2005 (UTC)

What is NokiaNet?

Hi,

I have been in the mobile wolrd for in excess of 15 years and I have come across a type of Service similar to Blackberry but referred to as NokiaNet.

I will appreciate if anyone can help me understand what this Service is?

Many Thanks

Rohit

What are all the hidden processes in windows XP?

If I press ctrl+alt+delete, I currently have 31 processes running, most of them unknown by me.

Is there any place (preferably wikipedia) I can find a list of what these are?

You can usually just type the process name into a search engine (like Google) and you'll find information on it as the first result.

Or, you can list them here, and we can try to tell you what they are. --Pidgeot (t) (c) (e) 15:08, 27 September 2005 (UTC)

five sense's

• what are the five sense's ?

• See five senses. --R.Koot 15:49, 27 September 2005 (UTC)

• also, note that there seem to be more than 5 --WhiteDragon 17:38, 28 September 2005 (UTC)

• See also Greengrocers' apostrophe. --bodnotbod 18:01, 27 September 2005 (UTC)

Jumpdrive's, Compadibility, size, and price.

Can anyone please help, and find information about a Lexar Jumpdrive secure, 256 MB, and any other type of Jumpdrive, Nerd Key, Flash Drive. I am looking for the size, a advantage, a disadvantage, and a discritption. Any ideas? -Lord Ned

• Dere are plendy of user reviews ad Ciao of various dypes of sdorage. Epinions hosds dem doo. I expecd, if you were do dake a look ad Amazon you'd drack down commends of the producds of a derrific boundy of some magnidude. Also please see Compuder Sdorage, Flash memory (bah!) and USB Flash drive (double bah!) --bodnotbod 18:19, 27 September 2005 (UTC) (or Bodnodbod. Dang I wish I'd acdually called myself dad ad de oudsed.)

KK Thanks Lord Ned

That's a pretty bad cold you have there. DJ Clayworth 21:44, 28 September 2005 (UTC)

carbon dioxide in the body

I understand that carbon dioxide buildup in the body is what triggers "air hunger" in a heavy carbon dioxide environment, but that a helium environment wont cause such a reaction, leaving a mamal unable to sense the loss of air and therefore vulnerable to suffocation. Is this true?

• Yes, I believe it is, at least in humans (not sure about all mammals). The body doesn't detect lack of oxygen, it detects too much CO2. So if you displace the oxygen in a room with an odourless gas like He or N2, there's no feeling of suffocation to warn you that you can't breath. -- Bob Mellish 17:50, 27 September 2005 (UTC)

• Though if you're a member of the popular mammal species homo sapien, and are in company, you might detect an unhealthy amount of helium in the atmosphere when you all start talking like Disney's Chip 'n' Dale --bodnotbod 18:49, 27 September 2005 (UTC)

No, no, no, DrBob. The CO2 in the blood that drives breathing comes from body metabolism, not the surrounding air. Prevention of breathing it out is what makes you feel out of breath. Breathing is also driven by hypoxia or rising acid level, but these drives are weaker than the CO2-linked response. alteripse 21:09, 27 September 2005 (UTC)

• So what mechanism prevents you breathing out CO2 in a non-oxygen atmosphere? Or am I misunderstanding you? -- Bob Mellish 22:05, 27 September 2005 (UTC)

Nothing prevents you from breathing out CO2 in a low oxygen atmosphere. That's why people can sometimes die of hypoxia as long as they can exhale CO2. alteripse 00:21, 28 September 2005 (UTC)

Let me see if I can make it clearer. There are at least 5 types of control for the physical act of respiration: (1) voluntary breathing, e.g., blowing at something or talking; (2) involuntary neural control based on a rhythm of breathing controlled by neuronal pacemaker cells in the medulla; this is what keeps someone breathing in a vegetative state and why a brain injury that affects the medulla can kill someone; (3) chemical control by arterial blood carbon dioxide levels; rising levels stimulate breathing; (4) chemical control by arterial blood oxygen levels; falling levels stimulate breathing; and (5) chemical control by arterial blood acid (pH) levels; falling pH stimulates breathing. The CO2 and acid in the blood are generated by aerobic metabolism of body cells no matter what you are breathing.

Exhaling CO2 does not depend on the content of the ambient atmosphere but whether your lungs are working and your airway is unobstructed. Physical obstruction of breathing by a hand over your nose and mouth will prevent you from exhaling CO2 and inhaling O2, as will prolonged closure of the epiglottis as occurs in drowning; as will failure of respiratory muscles (e.g. Guillain-Barre syndrome) or severe lung disease (e.g., adult respiratory distress syndrome). In all these cases you die with a high CO2 level in your blood, low pH, and low O2 level.

However if nothing impairs your breathing but the oxygen is removed from the air, you will continue to exhale CO2 but your O2 level will fall. Most people and animals sense this before they become unconscious from hypoxia but not always, and increased breathing of a low-oxygen atmosphere does not improve the oxygen levels and the person or animal will become unconscious fairly quickly. This is why people are overcome by collections of heavy gas in sewers or chemical tanks, and a rescuer can die of hypoxia before extricating the initial victim. Just before their respiration becomes impaired, they will have a low blood O2 level and a low CO2 level; as the hypoxia affects the medulla and breathing ceases the CO2 and acid level will abruptly and rapidly rise.

The earth's atmosphere is about 21% O2 but less than 1% CO2. The rest is mainly nitrogen, but you can substitute all kinds of other gases like helium as long as you supply at enough oxygen and the other gas is not intrinsically harmful (like carbon monoxide). CO2 is not a damaging gas, but breathing an atmosphere of 21% O2 and 79% CO2 would result in rising levels of CO2 and acid in the blood because gas exchange in the lungs depends on a gradient between blood and ambient air.

Of the chemical controls, the CO2 drive is stronger than the O2 or pH drive. All of the chemical controls can gradually habituate to altered levels (e.g., as occurs in emphysema) and sudden changes can cause problems. A sudden drop of blood oxygen that causes hypoxia will impair and damage the brain in minutes. A sudden drop of CO2 (e.g., from hyperventilation) will upset the acid/base and cation balance of the blood and can cause a variety of symptoms, including panic. A sudden rise of CO2 in some circumstances can actually impair brain function and the neural drive to breathe: this is referred to as "CO2 narcosis".

Finally, it seems that all air-breathing vertebrates have similar respiratyor control mechanisms. Antoine Lavoisier discovered some of the properties oxygen by observing the effect on mice of altering their ambient air. This is probably way more than anyone wanted to know but does it answer your question? alteripse 08:59, 28 September 2005 (UTC)

So to summarize briefly, in a helium evironment, you would still have hypoxia and pH inbalances. Therefore, you would know to keep breathing, but the drive wouldn't be as strong because there was no CO2 build-up. Because you wouldn't be able to get any oxygen, you would die of hypoxia, possibly recognizing your discomfort but possibly not noticing before you fell unconscious then died. Is that basically right? Superm401 | Talk 21:39, 28 September 2005 (UTC)

You got it! alteripse 18:50, 1 October 2005 (UTC)

Fish

is goldfish coldblooded? - anon

• Fish are coldblooded by definition. - Mgm|^(talk) 20:32, 27 September 2005 (UTC)

Actually, I believe by their physiological processes rather than by human definition. alteripse 21:11, 27 September 2005 (UTC)

Tuna tend to keep an elevated body temperature, and swordfish have special muscles which keep their retina and optic nerves warm [6], but yes, most fish (especially small ones!) are cold-blooded.--Joel 23:13, 27 September 2005 (UTC)

Gasoline Shelf Life

Hi! I was wondering how long automobile gasoline lasts when stored in ideal conditions? Does its quality diminish? Does it last practically indefinitely? What happens? What does it turn into? The first question is the most important to me so feel free just to answer that one. Thank you very, very much! ~~Charles Reid (Houston, TX)

According to Chevron, their gasoline can be stored for about a year under ideal conditions[7]. We do have an article on Gasoline, although it doesn't seem to say much about long term storage.--inks 21:27, 27 September 2005 (UTC)

I recall a question on this a while back. The answer I got from my small-engines teacher when I was in high school is that it gets "gummy", which I assume means polymerization of the unsaturated hydrocarbons that are the most cost-effective way to boost octane number.--Joel 23:27, 27 September 2005 (UTC)

Also worth noting that in some countries gasoline is classed as hazardous, and it is illegal to store it in any quantity. Also note that in time gasoline will cause some types of container, especially plastics, to deteriorate. Shantavira 17:16, 28 September 2005 (UTC)

I also took a small engines course. I don't know the chemical terms for it, but it will partially solidify into a useless goo. This happens mostly in small things like the insides of a carburetor, but not in any significant quantity in a larger container. A while back, I took apart a carburetor that had been sitting with gas in it for a few years, and it had large chunks in the "bowl". --Phroziac^(talk) 00:30, 29 September 2005 (UTC)

Is that why it is stored in those drums?

Through being a moron and leaving gas in things when they haven't been used in years, I can firmly say that pretty much anything made to hold gas will not deteriorate from gas. I know that gasoline will melt pop bottles fast though... --Phroziac^(talk) 00:30, 29 September 2005 (UTC)

Gasoline will only stay fresh for about a month in a vented container, such as a fuel tank. It will change, and can cause a lot of engine troubles, such as the engine not running properly. It can also coat the inside of the engine with excessive amounts of junk. Interestingly, when it goes bad, the smell also changes, it smells more like actual varnish or paint then gasoline. You can, however, use a "fuel stabilizer", such as Sta-bil, which can be found at hardware stores, lawnmower shops, and automotive shops. It will last indefinitely with fuel stabilizer, as long as the container isn't open to the air. This includes vented gas tanks, though it will obviously stay fresher if it's sealed. Never leave unstabilized fuel in the fuel system for an engine for more then a month or so, it will gum up inside the carburetor or fuel injectors fairly quickly, and often requires soaking the carburetor in a cleaner and rebuilding it. I don't know anything about fuel injection systems, other then they are much better then carburetors. Also, this next part is original research, but apparently kerosene can be stored indefinitely in a sealed or vented container, and diesel goes bad faster then gasoline. --Phroziac^(talk) 00:30, 29 September 2005 (UTC)

Dr. Meyer

Kastle invented the presumptive blood test in the 1900's using phenolphthalein, then was further developed by Dr. Meyer later on. What was his first name?

Blood test for what? alteripse 21:24, 27 September 2005 (UTC)

I think he's referring to the inventors of the Kastle-Meyer Color Test, which uses a solution of phenolphthalein and hydrogen peroxide to detect the presence of blood via a color change. There is a passing mention of it in phenolphthalein. I've had no luck with Googling for Dr. Meyers full name though.--inks 21:35, 27 September 2005 (UTC)

Satellite imagery

Are there any satellites up there that will photograph to the clarity and detail of showing a man or woman walking on earth ?

If I told you, I'd have to kill you :) Our article on spy satellites has several listed that have a resolution of less than 1 m...so a person lying down might be distingusihed. However, a person standing up would present a much smaller cross-section to the satellite, the size of which would probably fall below the resolution availible.--inks 22:42, 27 September 2005 (UTC)

Diffraction means that a much smaller angular resolution than the 1 m reported would require either a) extremely large apertures (which are difficult to fit onto a rocket) or b) extremely small wavelengths (the atmosphere is opaque to ultraviolet light lower than a certain limit). However, if the satellite takes many, many photos of the same thing from different angles, number-crunchers with fancy algorithms can create a synthetic aperture to get around this problem. Unfortunately, this means much greater latency, and the requirement that whatever you're spying on stand still for many hours, something most people can't be relied on to do. If a large flock of satellites ganged up and all snapped a photo at the same time, they could pool their data and give an image fairly quickly, but that would be extremely, extremely expensive.--Joel 23:20, 27 September 2005 (UTC)

Would the satellites/cameras all have to be in different positions? Wouldn't a bunch of cameras on one satellite or even just one camera taking several shots be enough? I've wondered about this with ordinary cameras. If you take one shot the grain is the result of the resolution of the sensory chip or film used. If you take a series of shots, all slightly moved (which will automatically happen if you hold the camera in your hand) and you lay those images over each other (compensating for the movement, which will therefore have to have been measured) then the pixels will mostly only partially overlap. So one spot that's much smaller than a pixel will be measured in different ways, from which one may calculate the value for that spot as if one would have had a smaller pixel capturing that spot. It's sort of like a Very Large Telescope array. There the telescopes are not in the same position, but considering the distance to what's measured compared to the distance between the telescopes that hardly seems relevant. Another reason for getting not so sharp an image would be imperfections in the lens, but then that could be solved by using different lenses (ie different cameras). Part of me says this makes sense and another part of me says it's complete nonsense. Can someone make me whole again please? :) DirkvdM 19:47, 28 September 2005 (UTC)

But imagine you're a spy agency with no oversight, and can afford a CCD with unlimited resolution: eventually, the other components will impose resolution limits. I think the "different place" part is actually necessary once the aperture, rather than the sensor, is what limits your resolution. In this case, the aperture shouldn't overlap too much with where it was before/with the other aperture, but recording the difference in perspective isn't absolutely necessary, as it could also be calculated as part of the process of combining the images. But you can never put a sattelite in exactly the same place twice anyway. Geosynchronous sattelites are an apparent exception, but there's still some wobble involved. Part of the reason large arrays of radio telescopes are necessary is the huge wavelengths found in radio, compared to visible and to practical aperture sizes. I think perhaps several pictures from "the same place" could be combined to boost resolution when the CCD is the limiting factor, but it would take a different sort of math as far as I know.--Joel 16:58, 29 September 2005 (UTC)

And would that math then be complicated? Suppose I'd take several shots in rapid succession (all shifted slightly like I said), then shouldn't it be possible to write a computer program that combines them to a sharper image? (even if that would take my computer all night, it would still be handy for some photos like night shots (preventing blur)). DirkvdM 19:54, 29 September 2005 (UTC)

Yes, it appears to be quite complex. Do a Google search on "optical aperature synthesis" and see what you can find...--Robert Merkel 05:55, 30 September 2005 (UTC)

A few years ago, I saw an image taken from a satellite, of a little boy in his back yard, looking up. The boy was the son of one of the NASA scientists, and the scientist had told his son what time to walk out into the back yard and look up. The image was very clear, and the boy's face was perfectly visible and identifiable. User:Zoe|^(talk) 05:52, 1 October 2005 (UTC)

hematology

so wot's yer bloody question?

• See Hematology. - Mgm|^(talk) 07:49, 28 September 2005 (UTC)

standards in wiring

What is the purpose of standards in wiring?

largely so that other electricians than the one who installed it can go in and quickly be able to figure out how it works. Also, so that devices made by different manufacturers will be compatible with one another. -Drdisque 02:49, 28 September 2005 (UTC)

Safety is also an issue.

.9999… = 1?

How does point nine repeating (.9999…) equal one?

1-0.99… = 0.00000000… There are several other nice proofs, but I'm not sure if we have an article on the matter. I'm sure someone else can help you with that though. --fvw* 03:24, 28 September 2005 (UTC)

One way to see this is to observe 1/3 = .333..., so .999... (which is clearly 3 times .333...) must be the same as 3 times 1/3. Another way is to convert it to a fraction. Let X=.999..., then 10X=9.999..., and 10X-1X = (9.999... - .999...) = 9, so 9X = 9, i.e. X=1. If none of these do it for you, you might try the explanation at http://mathforum.org/library/drmath/view/55746.html. -- Rick Block (talk) 03:34, 28 September 2005 (UTC)

Actually, we do have an article on this: Proof that 0.999... equals 1 --Pidgeot (t) (c) (e) 12:14, 28 September 2005 (UTC)

From a no-equations-involved standpoint, we know that there are infinitely many numbers between any two distinct numbers on a number line. Now, what form would a number take to be greater than 0.9999... and less than 1.0? No such number exists, therefore 0.9999... and 1.0 are not distinct (that is, they are equal). — Lomn | Talk / RfC 13:27, 28 September 2005 (UTC)

Use a calculator to square the square root of 2 and deduct 1. This will confirm that 1 is 0.9999.... ;-) Shantavira 17:22, 28 September 2005 (UTC)

For the hapless reader that doesn't reallize the above is a joke, see round-off error and the field of numerical analysis that studies that kind of thing. - Taxman ^Talk 18:40, 28 September 2005 (UTC)

It basically follows from the completeness property of real numbers. Read the properties section of that article if you really want to dig into the gory stuff. Our article doesn't use the infimum and supremum language I learned in advanced calculus, but that was a while ago and I forgot the completeness formulation in those terms. Those articles cover the basics. - Taxman ^Talk 18:40, 28 September 2005 (UTC)

Aren't natural numbers and rational numbers mixed up here? I suppose one might argue that 0.99999.... equals 1.00000.... . But 1 (without a decimal dot) is a natural number and 0.9999.... might come infinitesimally close to that, but never reaches it. So for all practical purposes they're equal, but mathematically they aren't. Right? DirkvdM 21:04, 28 September 2005 (UTC)

Again, see the article, but to summarize, any two unequal real numbers (reals) have an infinite quanitity of reals between them. What reals are between .99999... and 1? Superm401 | Talk 21:45, 28 September 2005 (UTC)

0.999... can only be defined in terms of the limit of a series. The series is in the rationals, and it converges to a natural number, 1. That's it. One important fact you need to know is that there are no infintesimals in the theory of real numbers. There are some funky theories you get in logic courses that have infintesemals, and you can do stuff with them instead of limits; I don't know how you would define 0.9999.... in that scheme, but it's irrelevant anyway. -- SCZenz 21:57, 28 September 2005 (UTC)

It is also important to note that 0.999... is a number, not a process. There is no "getting closer", 0.999... is a number, period. In calculus you will learn that decimal numbers are compact representations of infinite series, and that the series represented by 0.999... converges to its limit, 1. Here again, "converges" is a static property, not a process. Vonspringer 04:21, 4 October 2005 (UTC)

One more way of looking at it: a real number is, by definition, not simply a sequence of decimals (in which case 1 and .999.. would be distinct numbers), but actually equivalence classes of sequences of decimals, where two sequences are the same if one has all 9s as its final digits and matches the other in all the other digits before the 9. The reason for wanting them to be the same is because the associated geometric series will converge to the same number. But of course that's not rigorous. You need to define the reals before you can discuss convergence of series, otherwise you'll have no guarantee of convergence to any number (the reationals are not complete). So the rigorous answer to your question, "why are the numbers the same?", is simply "because they are defined to be the same". -Lethe | Talk 16:21, 3 October 2005 (UTC)

severe hypoglycemia

• Our Hypoglycemia article may be able to help you out. Capitalistroadster 05:57, 28 September 2005 (UTC)

How can I view a unix manpage in Microsoft Windows?

How can I view the unix manpage <http://ccdoc.sourceforge.net/downloads/ccdoc.man> in Microsoft Windows? Masatran 07:24, 28 September 2005 (UTC)

You can download Cygwin and install it. When done, save the file to the man directory and a man ccdoc should be enough, or download and compile the ccdoc source (again, in Cygwin).

Afterwards, you can add the bin directory of your Cygwin installation to your path to be able to read the man page without having to enter bash every time. --Pidgeot (t) (c) (e) 09:37, 28 September 2005 (UTC)

Also try looking for programs to convert manpages to something you can read [8] Ojw 21:25, 30 September 2005 (UTC)

BEARD GROWTH

our forefathers ,most of them atleast, who originated from primates stopped using their tail which eventually led to most of the tail missing from the present day human.on the same logic with extensive shaving off of the beard since ages, why is it that it has not stopped growing? thanks. vinod.--219.65.45.74 10:27, 28 September 2005 (UTC)28/9/2005 1600h

• because that doesn't have much to do with evolution, you should get better teachers.. also human population growth is exponential, that means at some point, we break the evolutionary mold, in shorter words, we're an evolutionary dead end, much like the neanderthal, and you know what happened to that guy--205.188.117.71 03:54, 29 September 2005 (UTC)

It isn't enough that something not be useful for it to evolve away, it needs to have a detrimental effect. (See vestigial organ) A tail has muscles, bones, etc that need maintainance (and maybe get in the way for certain types of walking). I don't think a beard takes much of the body's resources to make. And I imagine that shaving has been in practice for a very tiny fraction of the time that not-using-one's-tail has. Frencheigh 10:38, 28 September 2005 (UTC)

"stopped using their tail which eventually led to most of the tail missing". No, it didn't. That is similar to the evolutionary theory of Lamarck, which has been disproven. Lamarck believed(among other things) that use of organs would cause them to grow while disuse would make them shrink. Again, this is not correct. Evolution occurs through natural selection(or "survival of the fittest"). In summary, all individuals pass traits(phenomes) to their children through genes. Those individuals that are most successfully adapted will be more likely to reproduce, as well as likely to reproduce more. Therefore, more descendants will have their phenomes and genes than those of the less successful individuals. Eventually, only the descendants with the superior adaptations survive, forming new species. Genes are modified through mutation. Superm401 | Talk 21:59, 28 September 2005 (UTC)

I aggree that, in proper terms, great apes stopped having (noticeable) tails, which then prevented us from using them. One thing to note is that, for an individual creature, disuse of certain organs (especially bones and muscles, as mentioned above) causes them to atrophy. This change doesn't propagate to new generations, but it is an easy-to-observe exampe of organs shrinking with disuse.--Joel 19:12, 3 October 2005 (UTC)

There are many evolutionary explanations for the distribution of human body hair. Some are plausible; some seem like just-so stories. alteripse 11:26, 28 September 2005 (UTC)

The important thing to remember is that, as long as we can shave/pluck/wax/depilate with reasonable safety and convenience, there will never be any evolutionary pressure against hair growth. We've been able to shave since the stone age, and to pluck at least since the bronze age, although, as noted above, that's extremely brief in evolutionary terms. --Joel 19:12, 3 October 2005 (UTC)

What is sirolimus

See sirolimus. The fastest way to find information and articles in Wikipedia is to use the Search box on the left side of your screen. TenOfAllTrades(talk) 16:19, 28 September 2005 (UTC)

multiple sclerosis

I'm not sure what your question is. See our article on multiple sclerosis for lots of information on that topic, however. TenOfAllTrades(talk) 16:19, 28 September 2005 (UTC)

hydrogen bonding

there are two types of hydrogen bonds.(1)intermolecular (2)intramolecular.amongst these,which one is more strong and why?

By any chance, was intermolecular forces supposed to read as Van Der Waals forces ? you may as well post the entire problem, I could use some practice with my differentials--205.188.117.71 03:51, 29 September 2005 (UTC)

According to Hydrogen bond, it's an intermolecular bond. So I assume that the intramolecular case you refer to would just be an "intermolecular" bond between two atoms that happen to be far apart in the basic covalent structure of the same molecule (contributing, e.g. to protein folding). That being the case, I would expect the two cases to be of equal strength if all else is equal. -- SCZenz 15:43, 28 September 2005 (UTC)

Please refer to the top of this page, and note that Wikipedia isn't here to answer your homework questions. TenOfAllTrades(talk) 16:16, 28 September 2005 (UTC)

On the bright side, if that was a homework question, what I said almost certainly wasn't the answer the instructor was looking for. ;) -- SCZenz 17:30, 28 September 2005 (UTC)

Cephlapods and regeneration

Can a squid or an octopus regenerate tentacles if one is severed?

• "the squid's tentacle would not grow back "[9] Samw 21:56, 30 September 2005 (UTC)

Wikipedia Problems??

I have noticed when i try to edit a post, i have to click on the "Edit" button for the post above. Has anyone else noticed this? Or is it just me?

This sometimes happens when a section header is not formatted correctly. Fixed (I think). --hydnjo talk 01:47, 29 September 2005 (UTC)

I think the poster is thinking as I did at first, and assuming a section's edit button is the one that follows the text. In fact a section's edit button is the one on the same line as the section's title, above the horizontal rule that preceeds the text; not the one that sitting there, temptingly, right where your addition will go. I found this counter-intuitive. And for long sections the edit button has scrolled off-screen. Sharkford 14:38, 30 September 2005 (UTC)

I believe the same problem occurs when headers are commented out -- don't know whether this is fixed or not. Dysprosia 22:23, 3 October 2005 (UTC)

Lord Ned

Lordned 17:39, 28 September 2005 (UTC)

The section edit link in the default skin is to the right of and just slightly above the section title. This can make it look as if the link applies to the previous section, when it does not. This is, I'm afraid, just soemthing you need to get used to. DES ^(talk) 17:53, 28 September 2005 (UTC)

On related issues, you delete a duplicate section by editing the whole page and removing it, or by editing one of the duplicates and deleting the entire contents, including the section header. I did this for your duplicate post. Also when you start a line with a space character it produces a fixed-font, un-wrapped, boxed text. This is usually not what is desired. Do indents by starting the line with one or more colons. It is not standard on wikipedia to indent the first line of a paragraph. DES ^(talk) 17:53, 28 September 2005 (UTC)

Ok, Thanks. When i went to try and edit the post, i click on the wrong edit "Opps"

That happens. Alos on discussion pages (like this one) it is a good idea to sign your comments with four tildas (like this ~~~~). DES ^(talk) 18:01, 28 September 2005 (UTC)

One more note; sometimes if there are multiple images stacked up next to an article, it will cause flaky behaviour of the [edit] boxes. None will appear next to one or more sections, and they will all pile up ([edit] [edit] [edit]) next to a later section in the article. TenOfAllTrades(talk) 18:39, 28 September 2005 (UTC)

he he... lol."::One more note; sometimes if there are multiple images stacked up next to an article, it will cause flaky behaviour of the [edit] boxes. None will appear next to one or more sections, and they will all pile up ([edit] [edit] [edit]) next to a later section in the article" thats one big problem...

63.199.33.66 16:38, 29 September 2005 (UTC)

puna multa

Dear all. I am trying to find out any information about "puna multa" which should be the name for a traditional finnish (scandinavian?) type of timber treatment based on natural whiting and rye flour. Please if you find any info let me know at (E-mail address removed). Thank you.

Hmmm. A number of links come up in Finnish when I Google that phrase, but my Finnish is, um, limited :) You might try asking one of the people listed at the Finnish Wikipedia Embassy if they can help you. --Robert Merkel 04:26, 29 September 2005 (UTC)

The word is properly spelled punamulta, and translates literally as "red dirt". It's a traditional type of red paint made of water, rye flour, iron sulphate, linseed oil varnish and Egyptian rouge, a natural red pigment consisting of hematite or iron oxide rich clay. —Ilmari Karonen 18:07, 25 October 2005 (UTC)

The paint is also used in Sweden, where it is called rödmull. A particularly well known variety is Falu red, named after the source of the pigment, a copper mine in Falun, Sweden. —Ilmari Karonen 18:18, 25 October 2005 (UTC)

Bad hurricane cycles

I was once told that every 40-43 years, a major hurricane strain happens. Is this true? If so, are the years correct?

Check our article on hurricanes; specifically, the "long-term trends in cyclonic activity" section. There is a very approximate estimate of a 50-70 year cycle for the Atlantic basin, though full-ocean coverage has not existed long enough to make a firm statement in that regard. — Lomn | Talk / RfC 20:15, 28 September 2005 (UTC)

hydrogen peroxide

Has an article here, if you, in fact, wanted to learn something about it. Not to pour salt in your wounds, but if you need something specific (that's not already in the cleverly hidden article), perhaps you should ask a question. ByeByeBaby 19:48, 28 September 2005 (UTC)

quantitative methods and physical planning

how do these quantitative methods help in the physical planning field?

Which quantitative methods? Chuck 20:35, 28 September 2005 (UTC)

I'll guess it's a follow-on to a homework question that the original poster should do himself. — Lomn | Talk / RfC 20:54, 28 September 2005 (UTC)

Lagrange Minimization procedure

Since you know how to frame the Section header as "==Lagrange Minimization procedure==" then please follow up with an actual question. Wikipedia is not a search engine. --hydnjo talk 00:00, 29 September 2005 (UTC)

Actually, someone using the "add a new question" link at the top never uses wikiformatting to create the header. However, the above is correct -- this is not a search engine. However, this link over in Miscellaneous may help out. — Lomn | Talk / RfC 02:16, 29 September 2005 (UTC)

Epidemics indiana 1850–1860

Since you know how to frame the Section header as "== Epidemics indiana 1850 - 1860==" then please follow up with an actual question. Wikipedia is not a search engine. --hydnjo talk 00:00, 29 September 2005 (UTC)

indiana

Hey, I live in Indiana! You might want to review the instructions at the top of this page, particularly the part that says "Questions are answered by humans, not computers. This is not a search engine." Chuck 22:21, 28 September 2005 (UTC)

PEANUT SKINS

ARE THEY GOOD FOR YOU TO EAT? JANET F.

Assuming that you don't mean the "shells" (the hard outer part that we usually throw away) but rather the thin, maroon colored "skin", I'd presume that they aren't bad for you to eat or they wouldn't be so readily available that way, but I suppose that same answer would apply to the hard outer shell as well! Also, the "meat" within called the peanut are OK for some folks and deadly for others. So, I have no idea if they "ARE THEY GOOD FOR YOU TO EAT? JANET F.", that's between you and your doctor. I can only tell you that they are not bad for me to eat. --hydnjo talk 00:25, 29 September 2005 (UTC)

If I had to guess, I'd say that they're not harmful. (I'm making the same assumption as Hydnjo does about what constitutes the 'skin'.) I suspect that they're loaded with insoluble fibre, which is good for your digestion. On the other hand, I find them a bit bitter and kind of dry, and they can cause an unpleasant tickle in the back of my throat when I eat them.

Ah; Google is your friend. An interesting link here. Apparently peanut skins are used as animal feed–suggesting that they're not harmful. It seems that they contain a number of useful fatty acids, too. TenOfAllTrades(talk) 01:44, 29 September 2005 (UTC)

what is a cell?

"Cell" can have many different meanings, depending on its context. Have a look at Cell and see which one you are interested in. Chuck 23:29, 28 September 2005 (UTC)

wonderland

who is the blue ferry?

Although this is when rather than who, I hope this is of some help. --hydnjo talk 00:31, 29 September 2005 (UTC)

Perhaps you mean the Blue Fairy, from the novel Pinocchio, who also features in the movie A.I.: Artificial Intelligence.-gadfium 03:45, 29 September 2005 (UTC)

Was there a furry in the "blue" (i.e., pornographic) version of Alice in Wonderland? I never saw it, but I would assume there was. If so, the credits would tell you who played what role.--Joel 19:26, 3 October 2005 (UTC)

What day is the North Pole tilted furthest from the Sun?

whatever day is the middle of winter in the northern hemisphere Jeremybub 02:46, 29 September 2005 (UTC)

• I don't think so. See solstice. The first day of winter. --jpgordon∇∆∇∆ 02:52, 29 September 2005 (UTC)

On the winter solstice, which is usually December 21, but can vary by up to a day (depending on leap year adjustment). Shantavira 08:58, 29 September 2005 (UTC)

What is the act of using your senses to view the world? 11 letter word

How about "observation"? --jpgordon∇∆∇∆ 02:52, 29 September 2005 (UTC)

Are we solving crossword puzzles here now? DirkvdM 12:49, 29 September 2005 (UTC)

Feces and foot

I just stepped barefoot on what appeared to be human shit in an urban alleyway in the Eastern United States. I was quick and enthusiastic with the soap and the water, but I am still concerned about infection risk. Contributing to my concern are that I have a three-day-old cut on the soul of that foot and that there was next to the shit what in the dim light of the alley could have been a spoonful of jam or an enormous clot of blood. I didn't step in this second substance, but am thinking that neither dropping blood clots nor shitting in alleys are signs of health on the part of this mysterious person with whom I have suddenly become so intimate. Am I in danger? Are there any symptoms I should watch for? Thanks — Pekinensis 03:26, 29 September 2005 (UTC)

• Pekinensense,

I would contact your doctor as soon as you are able. It is probably best to be safe than sorry in these circumstances. Capitalistroadster 04:11, 29 September 2005 (UTC)

Have you been vaccinated against Hepatitis B? If not, this is something to bring up on that doctor visit. - Nunh-huh 06:37, 29 September 2005 (UTC)

And, if you haven't already, clean the wound and disinfect it with something like iodine (the most common brand name solution is called "Betadine" as per normal first aid procedures. --Robert Merkel 04:21, 29 September 2005 (UTC)

Relax. You have already taken care of it with soap and water and your injury was more aesthetic than biological. But what the heck were you doing barefoot in a dim alley? alteripse 09:55, 29 September 2005 (UTC)

Thank you all for your answers. I've decided not to worry about it. I have been immunized for Hepatitis B. What was I doing? I was taking out the trash and thinking about February when I stepped in the same substance in the same place, and that the Universe would not be so perverse as to repeat such an incident when I happened to be barefoot. Thanks again. — Pekinensis 16:45, 2 October 2005 (UTC)

Elemental lithium

I have searched the Internet for a while now, and cannot find the answer to this question:

How much elemental lithium is in 300 mg of lithium carbonate?

I know, for instance, that 120 mg of lithium orotate contains 4.8 mg of elemental lithium. I need this information for comparison sake, as I run a Yahoogroup of people taking -- or switching to -- lithium orotate.

Sincerely, Gerald L. "Moss" Bliss, D.D. ALT-therapies4bipolar Yahoogroup

According to our article on lithium salts, the chemical formula of lithium carbonate is Li₂CO₃. That there's one carbon and three oxygen atoms for every 2 lithium atoms in lithium carbonate.

From our entries on lithium, carbon, and oxygen the atomic mass of each is 6.974, 12.0107, and 15.9994. From this, we can calculate the fraction of the compound that is made up of lithium is:

${\frac {2\times 6.974}{2\times 6.974+12.0107+2\times 15.9994}}\approx 24\%$.

Therefore, 300mg of lithium carbonate would contains about 72 mg of elemental lithium.

Please note that Wikipedia does not give medical advice, and that incorrect dosage calculations are a regular cause of avoidable deaths in hospitals. So, whatever you do, please don't start dosing yourself purely on the basis of some quick calculations of somebody who hasn't done chemistry since high school.--Robert Merkel 04:15, 29 September 2005 (UTC)

To illustrate the problem, that equation should be

${\frac {2\times 6.974}{2\times 6.974+12.0107+3\times 15.9994}}\approx 18.86\%$

or 56.5 mg lithium for 300 mg lithium carbonate. Be aware as well that the bioavailability of metal ions is different for different salts. Physchim62 09:10, 29 September 2005 (UTC)

Whoops! I wasn't trying to illustrate the point, but hopefully people will take notice of the warning now that I've demonstrated how easy it is to screw up! --Robert Merkel 12:27, 29 September 2005 (UTC)

Our article on lithium orotate is not referenced, so it is subject to even more caution than usual. It may or may not give you some ideas to compare the two treatments. You may well wish to ask yourself why the FDA does not approuve this treatment (or, even better, ask them and tell us why!). Physchim62 14:15, 4 October 2005 (UTC)

are the stars we see in the nights sky actually suns

They are actually stars, and the Sun is a star. Many of the stars are just like the sun, though some are much bigger, much smaller, or otherwise different. Some people, especially science fiction writers, do use the word "sun" (not "Sun") to refer to other stars, but to avoid confusion it's best to stick to "star". Notinasnaid 07:54, 29 September 2005 (UTC)

Except the Morning Star and Evening Star. -guety is talking english bad 14:53, 29 September 2005 (UTC)

suns and stars

Are the stars we see in the nights sky actually suns? and are there any other suns in our galaxy that is equal or higher in size as our own sun? Africadeedee

Yes, almost all of them are, except a very few might be planets. There are lots of other suns in our galaxy which are as big or bigger than our sun, but there are even more which are smaller. The smaller ones are usually dimmer, so the ones you can see are mostly the larger ones. See our article on stars for more details. If you find that article is too complex for you, then look at the Simple English article on Stars.-gadfium 05:32, 29 September 2005 (UTC)

Nuclear blast in eye of hurricane..

What would happen if someone detonates a nuclear device inside the hurricane eye. Will it disperse the hurricane system, nothing happen, or just something else will happen? What if they used the Soviet Era 'The Czar' super-sized H-bomb. Does it even matter if the device is detonated inside the eye, outside of it (near the clouds spur) or even an airblast above the hurricane system ? Thank you very much in advance.

bukhrin

I don't think anybody's ever asked before, though you probably could do a simulation if you had access to weather-forecasting computer code. One side effect that's easy to predict is the distribution of dangerous nuclear fallout over a wide area, which could render places in its path uninhabitable for years, perhaps even decades, afterward. --Robert Merkel 07:47, 29 September 2005 (UTC)

though you probably could do a simulation if you had access to weather-forecasting computer code. Don't forget to budget for several days on the nearest supercomputer. :)--inks 12:18, 29 September 2005 (UTC)

It would probably not do much to disrupt the hurricane. The energy in a hurricane (see [10] for example) is several orders of magnitude greater than the yield of existing nuclear bombs. Fredrik | talk 11:01, 29 September 2005 (UTC)

Interesting experiment though. A FAE (Fuel-Air Explosion) approaches the strength of a Nuclear Weapon by purely chemical means, so if this were done there would be no nuclear fallout from it.

They only approach the yield of the tiniest nuclear weapons, though. --Fastfission 16:03, 29 September 2005 (UTC)

I doubt it would do anything at all. Even a Tsar Bomba sized blast pales in the overall, cumulative energy present in a hurricane. If you look at our entry on kiloton you can see how much more raw energy natural phenomena has in general (the reason that the bombs seem so big, of course, is that they release all of their energy into a relatively small space and over a very small amount of time). --Fastfission 15:36, 29 September 2005 (UTC)

The NOAA answers this question in their Hurricane FAQ. — File:Ontario trillium sig.pngmendel ☎ 17:08, 29 September 2005 (UTC)

1. Delivering a nuke to the eye of a storm would require some fancy footwork, missile technology not something that your average troublemaker might have in the near term.
2. Do Google search ... there are places where you key in geographic location and how big some event to see damage from WMD, giant meteor strike, earthquake, other disasters.
3. Watching on TV news huge traffic jam of people evacuating at last minute, it occurs to me we are kind of asking for trouble, since this goes on TV news world wide to all kinds of audiences.
   1. major hurricane is coming, approx where, announced days in advance
   2. local leaders take forever to discuss the implications of what is obvious to everyone, who knows anything, such as
      1. here comes category 4-5 and the flood control is only designed to handle category 3, and the city is under sea level, so after landfall it will be under water
   3. during that predictable time frame when the local leaders cannot decide what to do, terrorists blow up major escape highways with conventional explosives, stockpiled in geographic areas where the Atlantic hurricane season is known to be active.

AlMac|^(talk) 19:12, 29 September 2005 (UTC)

To paraphrase NOAA:

• Before implementing this plan, you have a hurricane to deal with.
• After implementing the plan, you have a hurricane and a nuclear explosion.

Ojw 18:50, 1 October 2005 (UTC)

migraines

• Our Migraine article is quite detailed and would be a good place to start. Capitalistroadster 08:07, 29 September 2005 (UTC)

how to improve migraines

• Our Migraine article contains extensive information on migraine treatment. Your doctor will probably be able to advise of treatments if you suffer from them. Capitalistroadster 08:09, 29 September 2005 (UTC)
• Improve them? Few sufferers want them to get worse. Cure them perhaps was what you wanted to ask about. AlMac|^(talk) 01:15, 30 September 2005 (UTC)

I hear that Oliver Sacks finds his migraines to be quite entertaining, like a light show. I'm not sure modern medical science has found a way to turn ordinary sufferers into Hildegard of Bingen, but perhaps this person is looking for a way to improve the head trip.--Joel 19:39, 3 October 2005 (UTC)

how wind blows?

Is it because of earth's revolution or change in air density due to sun light?

Have you tried reading our article on Wind? There should be some information there. From what I can ascertain, there are a variety of types of wind that have different causes.. but you should definitely read that article. splintax ^(talk) 08:42, 29 September 2005 (UTC)

All wind is fundamentally caused by pressure differentials. Many factors affect that pressure, and the differing linear speeds(though constant angular speed) of rotation at different latitudes affect apparent direction. See also "Why does wind gust?" above. Superm401 | Talk 13:59, 29 September 2005 (UTC)

construction technology of rotating buildings

could you please show me the details and sections of rotating buildings?? and if possible the criteria etc too to implement it. 2nd year student, amrita

Several cities have restaurants on top of high buildings, in which only the top rotates. You sit at window seat, and in an hour it has rotated so you get to see the whole city. I have never heard of an entire building rotating. AlMac|^(talk) 19:15, 29 September 2005 (UTC)

Glasgow Science Centre does. Or was supposed to, anyway. Notinasnaid 22:22, 29 September 2005 (UTC)

The largest and most numerous rotating buildings would probably be radio telescopes. I think they use circular tracks, along which a motor on the outside of the building travels. Ojw 19:47, 1 October 2005 (UTC)

mobile phone

Hi,

my question is "why mobile phones are not allowed in petrol bunks?

Bharathi.

• Some people believe the static electricity create when a mobile phone is used could cause an explosion which would be detrimental near petrol. However, the Mythbusters tried to cause an explosion using mobile phones and couldn't succeed unless they purposely created loads of static electricity (far more than a phone could generate). Still, there have been accounts of faulty and exploding batteries in phones which could still cause problems near petrol. Hope than answers your question. - Mgm|^(talk) 11:01, 29 September 2005 (UTC)

I'm not satisfied with their test, actually: they didn't set the phone to vibrate. In most direct current electric motors, the commutator throws up sparks several times a second as the motor runs. But in fact, I agree that this is more a question for the "culture" section of the reference desk...one reason I'm unhappy with this recent segmentation of the project.--Joel 17:49, 29 September 2005 (UTC)

• They did do a follow-up experiment to address multiple issues viewers brought up, but I can't remember the result. Sorry. - Mgm|^(talk) 19:12, 29 September 2005 (UTC)
• Surprisingly I found an article on MythBusters Episodes the mobile phone myth is listed in season 1 (episode 2) and season 2 (episode 14). - Mgm|^(talk) 19:23, 29 September 2005 (UTC)

It failed both times. --R.Koot 10:10, 30 September 2005 (UTC)

IIRC, they didn't turn on the vibrator for the second test, either, despite all the sex toy jokes it could have sparked. Oh, well...my fault for keeping my criticism to myself the first time around. To be honest, though, I would expect the microphone holes etc. in a cell phone to be too small to allow a flame front to pass. --Joel 19:44, 3 October 2005 (UTC)

Botany

I want to know what is exactly subdiecious condition. If in a dioecious species, if the males are converting temporarily to hermaphrodites, what we can call this condition?

I believe the article for you is plant sexuality. It seems to give two answers to your first question, one more specific than the other, but both make "subdioecious" seem like a plausible anwser to your second question. — Pekinensis 13:08, 29 September 2005 (UTC)

Energy Drink Question

I was wondering if XS Citrus Blast energy drink was really made up of things that gave you energy or if it is simply caffeine with some flavor added in. Next, I was wondering if it would simply be better to just by a can of coke instead of the energy drink?

--Thanks, J

Found this using google. Active ingredients: Taurine, Caffeine, Ginseng, Vitamin B3, Vitamin B5, Vitamin B6, Vitamin B12. My guess would be that this contains more caffeine than a coke, so you need to drink less of it for the same effect. --R.Koot 16:08, 29 September 2005 (UTC)

If your diet is extremely bad, you might feel a lack of energy due to mild pellagra or some other deficiency disease, in which case XS Citrus Blast would make you feel revived beyond the sugar and caffeine...but eating a balanced diet would make you feel even better.--Joel 17:12, 29 September 2005 (UTC)

Is evolution scientific?

One of the reasons often given for not teaching Intelligent Design is that it is "not scientific", which as far as I understand means it cannot be experimentally disproven. What makes evolution "scientific", or rather what experiment would disprove evolution?

I don't think it's real at all, just another leftist conspiracy, much like... gravity, and that whole "round earth" business, If the earth is really round, and it really spins around the sun, then why don't I fall off when I'm on the bottom? Answer that smart guy--172.208.123.70 14:29, 2 October 2005 (UTC)

Evidence of evolution might be a good place to start. -- SCZenz 15:26, 29 September 2005 (UTC)

What you are referring to is the notion of falsifiability. Whether or not evolution is falsifiable depends on who you ask (creationists would probably interpret it to say no, philosophers might sit on the fence, scientists would say yes) — as a philosophical concept, it is not as cut-and-dry a test as people opposing creationism/ID usually make it out to be (though I personally think that in this instance, their overall conclusion is probably correct).. A lot of depends on whether you are taking evolution "as a whole" the entity which needs to be falsified or whether or not you are taking specific claims, and a lot of it also depends on what version of falsifiability you use. One fairly intelligent page which argues that evolution is falsifiable is Talkorigins.org: Evolution and Philosophy. --Fastfission 15:27, 29 September 2005 (UTC)

That is correct. I do not of any experiment that would disprove evolution, but that does not mean someone won;t come up with one sometime. This is impossible with Intelligent Design as you could always counter with "it was designed that way", while with evolution the theory has to modified or discarded. See Lamarckism, evolution, evidence of evolution, Intelligent Design and scientific theory for some more information. --R.Koot 15:28, 29 September 2005 (UTC)

Another way in which ID is unscientific is that it does not deal with a repeated mechanism of the natural world that operates under self-consistent rules. It just has some being who does what he feels like. -- SCZenz 15:33, 29 September 2005 (UTC)

Science restricts itself to hypotheses, theories, mechanisms, and processes that are consistent with our knowledge of the material world and explicitly excludes claims about supernatural processes or knowledge. Science cannot and does not claim that God does not exist or did not create the world, only that such claims cannot be evaluated from a scientific perspective and are not likely to advance our scientific understanding of the material universe. Since first proposed, an enormous amount of experimentally verifiable and directly observable evidence has supported the validity of the basic process of evolution and no evidence strongly undermines it. It is possible to imagine that several million years ago, several thousand years ago, or several minutes ago God created the world exactly to seem as if evolution is occurring, but none of these hypotheses fit with other scientific knowledge or seem likely to advance other scientific understanding or can be proven or disproven scientifically.

Science does not exclude the supernatural, but says that so far the supernatural does not lend itself to any scientific analysis, which is not quite the same thing. (But its so close it is the same thing for all practical purposes).

The objections that most intelligent people have with the idea of Intelligent Design are that it is (a) presented dishonestly (as not being intended to promote fundamentalist Christianity), (b) confuses people about what science is (by incorporating miracles and supernatural processes in scientific knowledge), and (c) misrepresents our current understanding of evolution (which is both dishonest and confusing). Most intelligent Christians make a distinction between evolution as a scientific way of understanding the changes and interrelationships of living things on earth, and most intelligent scientists do not claim to be able to scientifically prove or disprove the existence of God or whether he had a role in the formation or history of the universe. Does that help? alteripse 15:41, 29 September 2005 (UTC)

(adding during edit conflict with above three responses)

A scientific theory (versus just any ole theory) is one that makes testable predictions. As you intimate, a theory without testable predictions is impossible to disprove and rather useless to a scientist. So for instance, I could come up with a theory of everything that was simply a list of observed occurances: in other words a theory that simply described the way things are and said "this is how it is". That theory would not be a scientific theory, because it would make no new predicitions, not to mention being really unsatisfying as it wouldn't "explain" any observations with underlying principles.

A prof of mine once said, "every great theory swallows it's predecessor whole," meaning that for a new theory to gain ground it needs to explain all the behavior described by the old theory while making an entire set of new, experimentally testable predictions. A great example is quantum mechanics, which swallowed Newtonian mechanics whole and then made an entire set of new predictions which have been tested rather extensively. It's not complete, but it's more complete than Newtonian mechanics, so it was eventually accepted by the scientific community, which is now trying to find the next, more complete sucessor theory.

In contrast, Intelligent Design — like my first example — makes no testable predictions. It is therefore not a scientific theory and is completely ignored as a possible replacement for evolution by the majority of the scientific community.

Right now, evolution is backed by so many observations that all scientific debate in the field centers on the details, not the basic principle of evolution. I cannot therefore anticipate anyone developing a scientific theory that can explain all those observations without also having evolution at it's core. — Laura Scudder | Talk 15:43, 29 September 2005 (UTC)

(adding during edit conflict with above four responses)

Evolutionary biology is a living science which is full of falsifiable hypotheses. Every publication in systematics which overturns existing ideas about systematics disproves some idea about evolution. If existing phylogenies say that species A and species B are more closely related to one another than they are to species C, that is an evolutionary hypothesis. Now, suppose someone comes along and looks at the genetics of the two species and concludes that species A and C are closely related, and species B is more distantly related. Assuming that their data are sound, this person has disproven an evolutionary hypothesis. Another way of disproving evolution would have been the discovery of an invariant fossil record – that, no matter how far back you go, you find the same set of modern living species. If you could find modern species in hundred million year old strata, then you would have evidence to disprove the hypothesis that the species you found evolved.

It's a little like heliocentric theory – when it was proposed that the earth revolved around the sun, there was a competing hypothesis that the sun revolved around the earth. Heliocentricity was confirmed experimentally, so now someone could come along and say "this is an unfalsifiable theory". Difficult to falsify it now (although there are still geocentrists out there), because it has already been falsified. Similarly, the existence of a fossil record makes it look like evolution is unfalsifiable because there is overwhelming evidence that it has taken place. But it still remains falsifiable. Guettarda 15:46, 29 September 2005 (UTC)

Has geocentricity been fansified? As I understand it the theory works, but is just much more complicated than heliocentricity and it's customary to work sith the simplest solution. DirkvdM 19:43, 29 September 2005 (UTC)

Just a few notes: theories often don't swallow entire previous theories whole (they often decide previous aspects of theories are not longer worth paying attention to, a la Thomas Kuhn); and in this case we're not talking about falsifiability in the sense that any given result will necessarily either favor one whole theory or another (the heliocentric question is not a great example in this case, as there are no "phases of Venus" to compare it to in evolution); and lastly, one of the other reasons that scientists say ID is "not science" is because it invokes non-natural causes as explanations (i.e., it invokes the supernatural), and "science" deals only with the natural world (once you start a science of the "supernatural" world, there is no end of explanations which are equally plausible). The requirement of science to use methodological naturalism has been criticized by IDers (notably Johnson) who say that it necessarily promotes an atheistic view of the world (even though it was originally formulated by Christian scholars, mind you). None of these critics, though, have adequately (in my mind) provided an acceptable view of what a non-materialist methodology would be which doesn't immediately snowball into the possibility of introducing supernatural explanations into anything we don't understand (as a related problem, see god of the gaps). What "is" and what "is not" science is a difficult thing to determine, though, and after a few centuries of intense debate nobody has yet come up with a great way of determining such a thing (see demarcation problem). So it's a sticky issue in a philosophical sense. But most of this (on both sides) is more about politics than it is true philosophy. --Fastfission 16:15, 29 September 2005 (UTC)

re: "...what experiment would disprove evolution?" JBS Haldane famously said fossil rabbits from the Precambrian era would disprove Darwinism. David Sneek 18:07, 29 September 2005 (UTC)

There are lots of 'holes' in evolutionary theory, based partly upon inexplicable fossil evidence. But due to the fact that this evidence was created long before people were around to observe it, it is entirely possible the evidence has been corrupted in some way which is not detectable yet, or maybe ever. Take Piltdown Man as an example.

I think we have deviated from the original question significantly. The answer is yes, the theory of evolution is scientific, for that reason it remains a theory and probably will for some time as the complexity of proving it or disproving it will require a lot of modification of the theory.

Falsification is really about designing an experiment, making a prediction and checking if that holds true. So you might claim that you could create a new animal out of an existing animal. Such as a Russian experiment I once head of where over tens of years tame foxes were created by interbreeding the meekest specimens over and over again. But if something like this fails then that doesn't prove that you couldn't have make it work if you would have done it differently. The big problem here is that there are too many factors at play to design a good laboratory style experiment. Which makes it almost impossible to falsify the evolution theory (or rather too easy, which would invalidate any falsification). And it's even worse with fossil evidence. There's always the chance that you'll find an animal you can't explain. But if you only know the overall way evolution works and not all the intricacies then it's quite possible you can't think of a solution yet. But the point is that it is falsifiable (there is the possibility to find something that disproves it) and that makes it scientific.

Also, as said before, there is just too much evidence to suport it. It 'works', as proven by farmers who have bred loads of types of animals to suit their needs. And it just makes too much sense. It is hard to believe that it might not work. Offspring are on average like their parents and less adapted individuals are less likely to get offspring. Both true right? Take it from there and you get evolution. Whether this explains everything (such as the origin of life) is an altogether different matter. But that this basic form of evolution takes place is just too unavoidable not to be true. DirkvdM 19:43, 29 September 2005 (UTC)

The accumulation of previous evidence has nothing to do with whether a theory is falsified or not or replaced with another. The Newtonian theory accounted for every observation thrown its way with the exception of about three. But those three (perihelion of Mercury, Michelson-Morley experiment, and lastly the deflection of starlight around the sun) were enough to topple the whole thing for most physicists in favor of Einsteinian Relativity in the early 1910s. "Falsification" doesn't at all mean "replace with something totally difference which gives totally different answers." Young Earth Creationism will never be the answer to a falsified evolution (too many simple observations contradict its "predictions" over and over again), but that doesn't mean that the current understanding of evolution (as either fact or theory, in the Gouldian sense) is the last word in any event. --Fastfission 02:25, 30 September 2005 (UTC)

Indeed, falsification has nothing to do with whether there exists an alternative. Forgot to react to that. DirkvdM 17:32, 30 September 2005 (UTC)

AirBus 360 Questions

Does anyone rember the AirBus 360 Emergancy landing? What if when they touched down on back wheels, one (Or both) of the back wheels broke? Would it tip over, and rip the wing off, and the jet enginer blow up? Or would it just tipp and scrapte the tip, and spark? Any Ideas appreciated Lordned 16:44, 29 September 2005 (UTC)

Did you mean JetBlue Airways Flight 292, which was an AirBus 320, or this another incident? In any case, commercial airplanes always touch down on their back wheels first--if one broke, the results would be rather catastrophic, I suspect. Even less-than-complete landing gear collapse can result in ground loop, according to the landing gear article. -- SCZenz 18:11, 29 September 2005 (UTC)

Yes i did mean " Did you mean JetBlue Airways Flight 292, which was an AirBus 320" So i was off by 40... Thanks. I wonder what would happend with a stratofortress. Or a boing 747, or an A-10.... Maybe will never know.

Become an aeronautical engineeer / mechanical engineer, and you might be able to get a job simulating those kinds of events. You'd probably need a CAD design of the plane to simulate how each bit of the landing gear fails and what else it affects, rather than just using a desktop flight simulator. Ojw 21:29, 3 October 2005 (UTC)

Chemical Structure of HCl

Gah! I'm supposed to be finding the structural formula for Hydrochloric acid. Even on google, all I get is various diagrams of drugs. Help!

• Please tell me this is a joke.. no wait, hold on, while I'm here does anyone know the chemical formula of H2O?--172.208.123.70 14:26, 2 October 2005 (UTC)

The structure of HCl is very simple, it is just H-Cl, now hydrochloric acid is a bit different as HCl needs to be dissolved in water to act as an acid, but the term structural formula is not very appropriate to that.

Have you looked at the Wikipedia article: Hydrochloric acid? --hydnjo talk 20:48, 29 September 2005 (UTC)

Hydrochloric acid is an ionic solution, meaning it consists of H⁺ and Cl^- ions moving around freely in solution (presumably in water). As such, it has no molecular structure. If you mean hydrogen chloride gas, it's just the two atoms with a single covalent bond: H—Cl. --David Wahler (talk) 13:59, 30 September 2005 (UTC)

Mallard Duck

I was told mallard ducks lay from 8 to 13 eggs before they start incubation. My duck has laid 19 eggs and shows no signs of incubating them. How long can the eggs survive and will she ever incubate them? Thank You

Mallards are wild birds. But farmyard domestic ducks are bred from Mallards, and can look similar. Farmyard ducks have been selectively bred (1) to lay more eggs (makes more money for the farmer) and (2) to ignore their eggs after laying (so the farmer can collect them up, and so as not to waste time that the duck could spend laying yet more eggs). So I suspect your bird is a farmyard duck. If you want to hatch the eggs, you will need to buy an incubator and become a poultry farmer. MPF 21:26, 29 September 2005 (UTC)

On the other hand, it might just be simpler to make some omelettes. ;-) Shimgray | talk | 21:34, 29 September 2005 (UTC)

Portable Application Environments

What are Portable Application Environments? How about mobile computing systems? What would you need to know to be a software programmer in these fields?

Thanks! James

This ZDNet article (which is the first result that came up in a Google search) explains that portable application environments are, essentially, an API that can be implemented to run on multiple operating systems and architectures. The Java programming language and its associated bits are the best known example, while the Microsoft .NET environment is another (along with a compatible open source project, the Mono development platform).

I assume that mobile computing systems refers to developing software for personal digital assistants and advanced mobile phones.

To become a professional software programmer in this field, like other types of programming, you should ideally go to college and do a degree in software engineering or computer science. To get experience in these specific portable application environments , you can download basic development tools for at least Java and Mono for free, and start learning them yourself. If you own a PDA or some mobiles, you can download development tools for them, too, and start experimenting with programming on them.--Robert Merkel 22:59, 29 September 2005 (UTC)

There's good theory, and there's real world.

I have not yet learned how to draw pretty pictures in Wiki like so many other people do.

Draw a triangle and at each apex place a word

Quality

Features

Speed to Market

These are the goals of anyone developing software for any market ... you want good stuff, interesting stuff, and get it out there before competitor companies get their stuff to market. In recent years quality has been sacrificed for the other two. Examples of quality is good security, not at risk of viruses malware, personal privacy not at risk of being violated, it doesn't break with stupid error messages.

Who is General Protection Default & why is the military interested in messing with my computer? <G>

Thus if you apply for a job at some company that wants to compete in this field, perhaps they not care about quality either, just cool features, rapidly developed. AlMac|^(talk) 03:26, 5 October 2005 (UTC)

where is ghana ?

• See Ghana, which has a location in the first line and a nice clear map. Shimgray | talk | 21:22, 29 September 2005 (UTC)

Hybrids and percentile differences in DNA

What is the percentile difference in DNA between Horses and Donkeys?

For two species to hybridize what is the minimum percentage of DNA that they must have in common? Or does it vary based on the complexity of the organisms?

What is the greatest percentile difference bewteen DNA in Humans?

p.s. How do I watch just my question? --RPlunk 22:17, 29 September 2005 (UTC)

I do not believe you can put your question in Wiki watch list. Here is how I watch my question(s) (only one so far):

1. Post the question hopefully correctly.
2. Get to table of contents and use that to link to the question.
3. The url is now just of the question.
4. Use my browser to capture this place to return to at a later date or time.
5. Do so.

AlMac|^(talk) 01:19, 30 September 2005 (UTC)

IANAB, but you might want to look up the major histocompatibility complex...it seems that not all DNA is created equal, when it comes to reproductive viability. --Joel 19:51, 3 October 2005 (UTC)

who was galileo?

• Who was he?? A heathen I say!!! Spouting heracy about the sun not rotating around earth!!! I'll believe that when I see it.....dirty revolutionists, gravitaion is JUST A THEORY!!!!!!!--172.208.123.70 14:24, 2 October 2005 (UTC)

If you try typing "Galileo" into the search box on the left of this page, and had clicked "search", the very first link is to Galileo Galilei, the subject of your question. --Robert Merkel 22:42, 29 September 2005 (UTC)

Should there be a template for this sort of response? ;) -- SCZenz 22:53, 29 September 2005 (UTC)

I was going to create one which had the format of {{seearticle|Galileo Galilei}} but the amount of coding there is really not much less than "See our article on Galileo Galilei". Plus, we'd lose an opportunity for snarky comments! --Fastfission 23:44, 29 September 2005 (UTC)

But we could put a snarky comment in the template, and make the same one every time! Wouldn't that be fun? -- SCZenz 00:28, 30 September 2005 (UTC)

Create a special 'insult of the day' template that changes each time you view it -- that way you can spend your time coding MediaWiki instead of working at the reference desk. Ojw 21:16, 30 September 2005 (UTC)

For technical matters, you can crib off of the stub template from Uncyclopedia, but I'd prefer it if the humor itself came from in-house. They have a pretty slick setup, with a random result every page load. --Joel 20:08, 3 October 2005 (UTC)

Seizure Trigger?

In my psychology class today, while the prof was lecturing about seizures and the brain areas that cause them, another student actually experienced a seizure. Those around him began to call for help and the prof had someone call an ambulance. What I would like to know is whether or not such episopdes can be triggered simply by the discussion of the disorder, or if the lecture and the actual seizure could in any way be related. The prof was not showing any multimedia sequences when the event occured. Thanks

Seizures are not triggered by discussing them, but pseudoseizures can be. alteripse 01:16, 30 September 2005 (UTC)

Peer-to-peer wiki?

Would it be technically possible to develop something like a wiki on a peer-to-peer basis? I am thinking of the vulnerability of wikis to censorship, particularly the Chinese Wikipedia, which has been blocked in the past. I am not proposing anything, just wondering whether it would be possible. Thanks.--Pharos 22:58, 29 September 2005 (UTC)

Yes, it is certainly possible, but who's to stop the censors from blocking the place to download the client from? -Drdisque 00:45, 30 September 2005 (UTC)

Technically possible? Sure. Easy? Not so much. The file sharing peer-to-peer programs (like kazaa or Napster) solve a problem closer to traditional web servers which is distributing the same content to lots of users. Rather than music or video files something like these programs could easily distribute static web pages. The question these sorts of clients throw out to the distributed network is basically "does anyone have a copy of <x>"? All the copies are presumably identical, so if any peer has a copy it's good enough. The essence of a wiki is that the web pages are writable as well as readable by anyone. This makes the question that would need to be thrown out to the distributed network "who has the most recent copy of <x>"? The naive peer-to-peer way to do this requires asking everyone in the network, which would not be feasible for anything except a trivally small network. The trick would be to allow the question to be answered without explicitly asking everyone in the network. If there aren't any centralized servers keeping track of all the content and who has what, I think this is at least a reasonably difficult problem. -- Rick Block (talk) 01:25, 30 September 2005 (UTC)

Aside from the problem of efficiency, there's also the question of security and vandalism prevention. There's nothing to stop anybody from setting up a peer which replaces every page in the wiki with spam and always distributes it as the most recent version. Perhaps you could set up some sort of dynamic, voting-based blacklist but it's not likely to be very easy. --David Wahler (talk) 13:51, 30 September 2005 (UTC)

How about this: everyone keeps a database of which page was edited when. Updates on this get syndicated to everyone. Everyone keeps a running copy of N articles, and subscribes to the diffs (which they request by watching the database and asking "anyone have that new update to WP:RD from 13:51, 30 September 2005? I think my copy is out-of-date." The system is set up so that at least M copies of this article are maintained, and during off-peak hours, the copies are compared and rectified, by majority rule. Especially if archive distribution (i.e., who keeps what article) is random, and if M is fairly large, this would seem to make vandalism more difficult than it currently is for Wikimedia. This seems plausible to me, but ianane (I am not a network engineer). Feel free to poke holes in this scheme if you see an opening. It would also be nice, because you could assign high M to popular/controversial artilces and save some bandwidth.--Joel 20:19, 3 October 2005 (UTC)

You should check out Freenet. Running a Wiki on it maybe possible... Haon 11:46, 5 October 2005 (UTC)

Global warming

What is global warming?

Please see Global warming. -- Rick Block (talk) 00:20, 30 September 2005 (UTC)

Tis just a wacky liberal conspiracy theory, like evolution and gravity....!

what is carbon dating

Not my sister, I can tell you that much! Seriously, though, see Carbon dating. -- SCZenz 00:37, 30 September 2005 (UTC)

Is that the kind of snarky comment you wanted to put in a template? :) DirkvdM 18:05, 30 September 2005 (UTC)

Nah, that's the kind of snarky comment that proves we shouldn't have a template. It only works with carbon dating...! ;) -- SCZenz 20:18, 30 September 2005 (UTC)

In reference to this specific snarky comment, one would hope that whomever your sister is dating, that they contain substantial amounts of carbon :) --Robert Merkel 04:29, 3 October 2005 (UTC)

Which leads us to the unavoidable question if aliens would necessarily have to be carbon based. Which is a totally philosophical question which is not meant to suggest anything about SCZenz's sister :) . DirkvdM 18:45, 3 October 2005 (UTC)

History of Prednisone

Who discovered Prednisone and which drug company owned the rights before it became a generic drug?

• It was invented by Arthur Nobile. Not sure when the patent expired. --jpgordon∇∆∇∆ 01:38, 30 September 2005 (UTC)

Your link says the company was Schering. alteripse 01:55, 30 September 2005 (UTC)

what is the name for water tension

The surface tension of water, probably. AySz88^-^ 02:42, 30 September 2005 (UTC)

See also meniscus --PopUpPirate 13:07, 4 October 2005 (UTC)

What is circular DNA?

Can anyone tell me what circular DNA actually is? What is its difference with double helix DNA? Does it duplicate in the same way as double helix? Where can it be found? [this is not a homework question! It's just that I can't find anything about this in my books and google didn't help much] Thanks in advance.

Circular DNA is just what it sounds like: a strand of DNA that is formed into a loop. It replicates like all other DNA, it just doesn't have loose ends. It can be double-stranded or single-stranded. Some places you'll find it: plasmids, bacteria, and mitochondria. - Nunh-huh 03:04, 30 September 2005 (UTC)

In most cases, it's double-stranded, and in those cases, it's not different from a double helix; it still has a double-helical structure. The scale at which the double helix appears is much smaller than the scale of the circle formed by the DNA. Imagine if you took a telephone cord (the coiled kind used to connect the handset to the base on corded phones), unplugged both ends, then plugged both ends into one of those connectors usually used to connect two cords. The cord would now be circular on a large scale, but still coiled--helical--on a smaller scale. Similarly, double-stranded circular DNA is still a double helix on a small scale, and circular on a larger scale. Chuck 16:56, 30 September 2005 (UTC)

Also most bacteria have an enzyme complex that methylates their own DNA as a way of distignuishing it from invading viral DNA, it's essentially a way of adding specificity to certian bacterial lysases, so they don't cleave their own genetic material by accident.. I'm not sure but I imagine it would be hard to methylate helical DNA, but I don't know if the methylation would nesseserily change the conformation, of it it just takes advantage of the conformation change--172.208.123.70 14:16, 2 October 2005 (UTC)

Ignition point of wood in the absence of flame?

I am trying to find out at what temperature will wood ignite in the absence of an open flame? 150 degrees? 160 degrees? Peace. Denis.

• I couldn't tell you for sure, but I'm confident it depends on exactly what kind of wood we're talking about. Redwood? Oak? Maple? Mesquite? - Cobra Ky (talk, contribs) 04:00, 30 September 2005 (UTC)

I believe at least book paper spontaneously ignites at Farenheit 451 (233 Celsius), hence, the name of the book. I would expect most woods would require a higher temperature. -- Rick Block (talk) 04:16, 30 September 2005 (UTC)

Respirable Liquid

Hi. I saw in a movie AND in a misc documentary a "respirable liquid" where animals (including us) can breath with some resistence because the liquid is more dense than the air. Can someone please help me to find out what kind of liquid it is and his formulae? Thank you all in advance. Baruch.

Please see liquid breathing. -- Rick Block (talk) 06:22, 30 September 2005 (UTC)

Information system management

What is meant by metadata? What is meant by intranet and extranet? What is meant by an automated system?--Andeep 06:21, 30 September 2005 (UTC)Andeep

• See metadata, intranet, extranet and automation. - Mgm|^(talk) 07:47, 30 September 2005 (UTC)

Why a pair of bones?

Human beings (and possibly all vertebrates) have two bones parallelly placed in their limbs: Radius and Ulna in the arms and Fibula and Tibia in the legs. But why two bones instead of one? I mean why did the humans body evolve in such a way as to have a pair of bones? What advantage does having two bones have over one single bone that is strong enough ?

Impact and forces are spread over a larger area, without the additional weight that one big bone would add. Additionally, if one bone is broken, then the other will provide some kind of support whilst it heals. This is not important now, but a long time ago, in early land based animals, this may have been a difference between that creature surviving or dying (and this makes a big difference over a few million years of evolution) Proto t c 10:07, 30 September 2005 (UTC)

In additions to the excellent reasons given above, two bones work better than since our joints do not freely rotate in all directions. Think about pronating and supinating your hand when your elbow is held still at 90 degrees. Try to imagine a one bone system that would allow that. You will get the idea. Finally, historical contingency: i.e., many biological mechanisms are not the most efficient imaginable but show traces of gradual imporovement over earlier versions that originally served for other functions. alteripse 10:26, 30 September 2005 (UTC)

The responses above explain the uses to which these bones have been put by modern animals, but of course the real reason why we have two bones in this position is that our ancestors had them, and they had them because their ancestor had them, and so on back to the osteolepiforms — crossopterygian ancestors of the tetrapods — which had a radius and ulna articulating with their pectoral fin, and a tibia and fibula articulating with their pelvic fin. (Eusthenopteron is a typical osteolepiform from the late Devonian).

There's a detailed description of the anatomy of Eusthenopteron at [11]. See also "The evolution of tetrapod limbs: How did fishes obtain their limbs?" by Keiko Shimizu-Nishikawa (a missing "next" link after page 6 means you need this link to read the rest). Gdr 20:08, 7 October 2005 (UTC)

staggered vs eclipsed conformations

hi, mu question is what kind of steric energies contribute to the energies of staggered conformations, and which ones contribute for the energy of eclipsed conformations in the case of ethane. thank you

cabi.

• hum, let me think, DO YOUR OWN HOMEWORK, and also, try a little harder to rephrase the question so it doesn't sond like it's right out of a text book, they do have a verbal section on the MCAT you know?--172.208.123.70 14:10, 2 October 2005 (UTC)

• Steric effects are mostly caused by the repulsion of the cloud of electrons surrounding atoms in close proximity of eachother. - Mgm|^(talk) 07:51, 30 September 2005 (UTC)

sex toy

I have a problem in my penis physic and I wanted to know if there is a artificial penis which could be able to inject my cum to my wife's reproduction system or not .

Artificial insemination is indeed possible, but it's not performed with toys. In vitro fertilisation may be another option if you wish to have a child but are not physically able. The best way to start would be to simply get in touch with your doctor. Of course, the Wikipedia:Medical disclaimer applies. Garrett Albright 09:46, 30 September 2005 (UTC)

Right, not toys but kitchen utensils, like a basting syringe. NOTE: I am not recommending you try this and can think of a few potential risks. alteripse 10:21, 30 September 2005 (UTC)

Actually, I remember reading about a strap-on dildo that served this purpose. AFAIR, it was used by women when they wanted to simulate a male ejaculation, but you could obviously use it in this case by using real semen instead of fake. ? Kieff | Talk 10:33, 30 September 2005 (UTC)

Need a documentation tool for C

I have many C files with Javadoc-style comments. Each statement contains a comment before it. I need to generate documentation from this. I am looking for a tool which takes the C files and generates a file from which the documentation and the corresponding source code can be easily extracted (ie, more easily than by parsing the source code). I tried Ccdoc but it processes only header files. I tried Doxygen but it loses the correspondence between the comments and source code. —Masatran 12:44, 30 September 2005 (UTC)

You can set Doxygen so that it creates HTML files that are visually identical to your source code, except with code colouring, and hyperlinks everywhere so that you can follow relationships -- this output seems to be much closer to what you describe than the default doxygen output. Haven't got a copy handy to tell you what the option's called, I'm afraid. Ojw 21:13, 30 September 2005 (UTC)

Something like Perl is Your Friend; if I understand your problem correctly, languages such as Perl are designed for particularly this problem. It's not really harder than "parsing the source code", though. Dysprosia 22:20, 3 October 2005 (UTC)

Unique Human bodypart?

Hi, is there a body part unique to humans? e.g. eyebrows. Thanks – Ieuan Willox

I can't think of an obvious one. However, teeth are often unique to a given species – one of the points of contention over homo florensis involves the numbers of roots on a molar, or something – so you could possibly argue that our teeth are, in fine detail, unique to humans. Other than that, I suspect most things are shared with some form of ape. Shimgray | talk | 13:10, 30 September 2005 (UTC)

The obvious one is People have a much larger brain than any other creature.

Not at all, a wale brain weighs nearly 8 kg (next to our puny 1.5kgs), see Whale for more information. --fvw* 13:29, 30 September 2005 (UTC)

Didn't know that, that is why I go to Wiki

Actually, contrary to popular belief, whale brains are pretty unimpressive for their body size, and don't really imply great intelligence (some dolphins, though, do have rather large brains for their body size).--Pharos 15:38, 30 September 2005 (UTC)

Of course the human brain doesn't nesseserily imply intelligence either (;--172.208.123.70 14:05, 2 October 2005 (UTC)

Eyebrows look unique, but most other creatures are so furry the eyebrow is just part of the fur

I don't think there's any, because we didn't evolved all that as a species except for parts of the brain. ? Kieff | Talk 14:47, 30 September 2005 (UTC)

I suppose your phrase was supposed to be "we didn't evolve all that recently as a species". Good point, because we are rather lonely as a species; there's just one race (contrary to popular belief) and our closest relatives aren't all that close (apparently somewhere in our evolutionary history we made a very 'close escape' somewhere). So it's only because we're so young that we haven't evolved further away from other animals. But what parts of the brain are you talking about? I thought that it was just the size (relative to our bodies) that makes our brain unique. DirkvdM 18:29, 30 September 2005 (UTC)

Thanks for correcting. And in respect to that part of the brain, see neopallium and hippocampus for instance. ? Kieff | Talk 07:32, 1 October 2005 (UTC)

The hippocampus is one of the oldest parts of the brain (according to the article), so that is nowhere near unique to humans. Your neopallium caught me off guard, but that turns out to be simply the neocortex, which is something at least all mammals have (I believe). It is indeed what sets us most apart from other animals, but, again, only because of its size. DirkvdM 18:34, 3 October 2005 (UTC)

A philosopher might say that "consciousness" could count as a body part, but the cognitive scientist would ponder what that would mean and whether or not we know enough to exclude chimps and dolphins from this category. The historian would note that this debate goes back hundreds of years, even before the theory of evolution was accepted in any form. --Fastfission 15:31, 30 September 2005 (UTC)

Here's a philosopher who certainly wouldn't utter such nonsense! :) DirkvdM 18:29, 30 September 2005 (UTC)

Oh, so there's no unique body part, I was sure I'd read somewhere that there was but I must be wrong. I need this information for something I'm writing,and it wouldn't really need to be unique, I suppose, just unique of animals native to Britain? I know I'm asking a lot but I hope you can help.

Do our close primate relatives have Appendixes? User:Zoe|^(talk) 06:09, 1 October 2005 (UTC)

Do they have a belly button? (and did Adam?) Ojw 18:16, 1 October 2005 (UTC)

Now that you bring that up. Why are umbellical cords clipped and turned into bellybuttons? Is there a risk of infection? DirkvdM 18:34, 3 October 2005 (UTC)

Here's the first result for Googling 'appendix primate'. Apparently the discussion is still open on this. And I'd say it's a good candidate, since it's something that (as far as we know) has no function. And since it can get infected and is therefore a hazard one would expect it to evolve away. If other primates have it then it evolved before primates evolved and hasn't disappeared since. Which sounds unlikely. I've always thought this whole idea that there would have to be one thing that is unique to humans was bullshit (it's the totality of what we are that makes us and any other animal unique), but I hadn't thought of this yet. Good one! DirkvdM 18:34, 3 October 2005 (UTC)

Speed of light – where's the energy?

If the speed of light slows down when a photon (or em wave) meets an air-glass boundary, then what source of energy accelerates the light photon (or em wave) back to air-speed when it traverses the glass-air boundary?

It turns out that the photon loses no energy when it enters glass, even though it slows down, and therefore needs no extra energy to speed back up later. For the energy of photons we generally write $E=h\nu$, and the frequency ν doesn't change when the photon enters a medium.

I can't come up for a great explaination of why the energy doesn't change, but I can think of an experiment that might make you think it's plausible: tie together three sections of string such that the middle section is a thicker, heavier variety than the first and third sections, tie the end of your Franken-string to the wall, and start moving the other end up and down to make waves. You should see that the waves slow down in the middle bit, but no one is there at the string junction slowing down and then speeding up the waves.

There's no one taking energy out at the first knot and putting it back in at the second knot, so the wave must have the same energy when it's faster in the lighter string as when slower in the heavier string. Hope that helps. — Laura Scudder | Talk 14:16, 30 September 2005 (UTC)

There's an important distinction between the 'speed of light' and the speed of the photons that make up that light. Our article on speed of light has a good explanation of this phenomenon. Essentially, photons travel a the full (vacuum) speed of light at all times. When they travel through a medium (like glass) they repeatedly run into and interact with particles (atoms and molecules in the medium)—the photons are absorbed and then reemitted. These interactions take a small but appreciable amount of time, reducing the apparent average velocity of the light through the medium.

Since the probability of these interactions varies with the wavelength (energy) of the photons, the speed of light in a medium is dependent on wavelength. This is how prisms are able to split light into a spectrum. TenOfAllTrades(talk) 14:26, 30 September 2005 (UTC)

Of course, you can have a fairly self-consistent understanding of light as waves, as long as you stick to the medium. The experiment above with strings of different weights also works in water of various depths. EM waves slow down in a medium because some energy goes into polarizing the medium, e.g. a slight shift in the electron cloud of the molecules the wave passes through. All three of these illustrate a very general concept called impedance, which has to do with the difficulty of creating the displacement/polarization that makes up the wave.

It's interesting to note that this slowing effect happens even when absorption and emission of a particular wavelength are forbidden by quantum mechanics, and so cannot be explained fully by Ten's analogy. But, as in his model, almost all of the energy of polarization is passed along to the next section of medium as the wave travels. The real brain teaser is, where is the energy stored as the photon travels through vacuum? If there's no medium to polarize, what holds the electric field? The short answer is, the photon speeds up so much that, according to special relativity, the media on either side of the vacuum appear to be touching one another from its perspective. Due to length contraction, it doesn't notice any gap at all, even a gap lightyears wide; due to time dilation, the energy is stored for exactly 0 time, therefore no medium is needed to store it.--Joel 19:31, 30 September 2005 (UTC)

A note about 'forbidden' transitions in quantum mechanics. You can actually get away with a great deal if you do it very quickly—very short-lived states have a very broad associated energy uncertainty. Joel's description fits best if you want to deal with photons as waves; the absorption/emission model works best if you want to deal with photons as particles. TenOfAllTrades(talk) 21:01, 30 September 2005 (UTC)

Educational technology companies in Boston

Are there any companies or projects working in educational/instrunctional technologies in Boston?

Thanks for any help!

Mary

Yes, almost certainly. Surely a Boston Yellow pages would be more useful than wikipedia in locating them. Ojw 18:11, 1 October 2005 (UTC)

CHANGES IN CHEST&LUNG VOLUME

WHEN PERFORMING THE HEIMLICH MANEUVER, HOW DOES THIS ACTION CHANGE THE VOLUME OF THE CHEST AND LUNGS? WHY DOES IT CAUSE THE FOOD TO BE FORCED FROM THE AIRWAY? WHOSE LAW EXPLAINS THIS?

THANKS

Have you read the Wikipedia article: Heimlich maneuver? --hydnjo talk 17:07, 30 September 2005 (UTC)

AND NEXT TIME COULD YOU REFRAIN FROM SHOUTING PLEASE?

Thank you. DirkvdM 18:47, 30 September 2005 (UTC)

It sounds like your teacher wants you to say "The Heimlich maneuver decreases the volume of the lungs" and "Boyle's Law explains this". You should read the latter article to find out why... - Nunh-huh 03:06, 1 October 2005 (UTC) (People don't breathe ideal gases, but it's close enough for government work<g>).

Penis Roll

On last week's episode of "Going Tribal" on the Discovery Channel, the host has his penis "rolled" by natives and it "jumped back into his body". Exactly what does this mean, what occurs, and how did this come to be considered a good idea? Also, does it work in reverse?

It sounds like a sort of reverse hernia. Some guys have un-descended testicles, perhaps it's similar to that. I don't know about the anthropology of it, but I'd guess that it started with someone playing with himself (by which I do not mean masturbation) and at some point acquired a cultural significance. Superficially, it doesn't sound like as bad an idea as piercing one's ears. It might jog someone's memory if you could remember what place these folks were native to...--Joel 21:22, 3 October 2005 (UTC)

Oysters and spirits fact or fiction

I've heard that mixing raw oysters and spirits ("hard liquor") can cause "harmful effects". Exactly what are the effects, and WHY? Or is this just a myth?

Well there is a connection in that some folks thought that the alcohol would kill any "bad" contaminants. It didn't and so started the urban legend. But on a more sober note, this FDA publication documents some potentially severe interactions. --hydnjo talk 19:22, 30 September 2005 (UTC)

That's not really an interaction. Alcoholism can cause liver disease, and liver disease increases susceptibility to Vibrio vulnificus, and oysters can be a source of Vibrio, but having a drink with your oyster causes no problems per se. - Nunh-huh 22:17, 30 September 2005 (UTC)

Correct, I did muddle interaction and susceptibility. The "urban legend" that I was referring to was the belief that if the oysters were of dubious origin then dunkin' them in spirits would rid it of Vibrio (which it didn't) and so when the ill effects occured the eater (rather than blame his poor judgement) would blame the oyster/alcohol combination to save face. --hydnjo talk 23:49, 30 September 2005 (UTC)

Supposedly oysters increase libido and liquor reduces inhibitions, it is not hard to imagine this can result in unexpected parents.

If the two of you have decided you'll sup on oysters and spirits in the first place, I suspect you're half-way there anyway.... - Nunh-huh 22:17, 30 September 2005 (UTC)

... how could you tell? Cheers, --hydnjo talk 23:27, 30 September 2005 (UTC)

Myth or not, I have eaten oysters at several restaurants which had specific cautions on the menu to avoid (much) consumption of spirits with oysters. No reasons were given. Notinasnaid 22:51, 1 October 2005 (UTC)

Urban legends do have a way of infiltrating our culture. Hey, if it's on the menu (or on the television set) it must be true. --hydnjo talk 06:09, 3 October 2005 (UTC)

tickling

Why can you not tickle yourself but shy away when someone tickles you.

Read the Wikipedia article Tickling and the Research section there has an explanation. --hydnjo talk 19:06, 30 September 2005 (UTC)

Apparently, you can tickle yourself, if there's a delay (or other signal-processing step) between your actions and your perception of their effects. I think the experiment involved a motor pushing against your hand -- if someone else controlled it, it tickled. If you controlled it, it didn't tickle. If there was a delay (i.e. no obvious correlation between your movements and the sensation) then it tickled more the longer the delay was. Ojw 18:10, 1 October 2005 (UTC)

Ozone Layer

What fraction of incoming solar UV light does the ozone layer absorb?

If you read the Ozone layer article you will get a better appreciation of what is going on. You'll also find the answer to your question there. --hydnjo talk 19:38, 30 September 2005 (UTC)

Software Chronic Crisis

can anyone explain or send me a link of a summary of Software's Chronic Crisis TRENDS IN COMPUTING by W. Wayt Gibbs, ???

• Set book? Notinasnaid 19:57, 30 September 2005 (UTC)

• • Is this what you are looking for? --hydnjo talk 20:40, 30 September 2005 (UTC)

Mysterious Smokey Lines Around Nuclear Explosions

In many photographs of nuclear explosions I often see smokey lines off to the sides (see [12] for an example). What causes these lines and why do they happen? I've heard of the rope trick effect but these aren't cause by guy lines, and they re visible for some time after the initial fireball.

• I believe that these are deliberately set markers, so that the effects of the shockwave on the surrounding air can be seen. See [13] for more. -- Bob Mellish 22:12, 30 September 2005 (UTC)

Thanks! I never imagined they were from smoke rockets. I always thought they were some product of the explosion themselves. --138.162.140.37 22:35, 30 September 2005 (UTC)

Butyric acid and odour of socks and blue cheese

Recently in my chemistry class we synthesised esthers using alcohols and carboxyilic acids. One such acid was butyric acid, a smell with a characterstically bad smell.

• I'm going to assume you mean esters, since esther isn't a word--172.208.123.70 14:03, 2 October 2005 (UTC)

My science teacher said that it was this acid that caused the smell of blue cheese and of smelly feet, but neither the wikipedia entry nor a web search seemed to agree with him. Is butyric acid responsible for these smells, and if not, what chemicals are?

• Our article on Butyric acid says it can be found in rancid butter, parmesan cheese and vomit. I don't know whether it can be secreted by smelly feet, but I live for the person with those feet if that's the case. - Mgm|^(talk) 22:29, 30 September 2005 (UTC)

Some things are agreed on: butyric acid has a very unpleasant odor, and it is butyric acid that gives rancid butter or spoiled meat their noxious aromas. Butyric acid is also found in sweat. I suspect that the smells of "smelly feet" and of blue cheese are rather complex affairs, and that the scent of butyric acid is a component of both smells, but that opinions may differ as to which scents predominate in these complex aromas (indeed, I rather suspect that the "mix" varies from foot to foot and cheese to cheese.... - Nunh-huh 22:29, 30 September 2005 (UTC)

It is plausible. Butyric acid is usually formed by the bacterial metabolism of fats, and sweat contains some fat. Physchim62 10:18, 2 October 2005 (UTC)

How does the Internet work?

We have a nice article on the Internet and HowStuffWorks also has a nice article on the infrastructure of the internet (click here) which happens to be the second result if I type the question you asked into Google (click and see). Please consider using a search engine to find your answer first. - Mgm|^(talk) 22:33, 30 September 2005 (UTC)

Heart

What causes blood to enter the right atrium of the heart?

You really should read the Heart and Atrium (anatomy) articles. They will will most likely answer your question. If you still have some confusion after reading the articles then come on back and we'll try to clear things up. --hydnjo talk 00:14, 1 October 2005 (UTC)

I don't think those articles actually do help much – nothing there that I can see on venous physiology. Blood is returned to the heart mostly via the deep venous circulation. These deep veins are enclosed inside contracting muscles, and contain valves that prevent backflow). Sixty percent of the blood present in the calf veins is expelled into the popliteal vein (below the knee) with a single, normal calf muscle contraction. [14]. The deep venous circulation goes into the inferior vena cava (from the legs) or superior vena cava (from above) and thence into the right atrium (from whence our articles have it covered). - Nunh-huh 02:52, 1 October 2005 (UTC)

In reading those articles I concluded that the return flow to the right atrium was a result of the pressure caused by ventricular pumping action that is, pumping blood by the action of the right ventricle into the pulmonary artery and then when it returns from the lungs through the pulmonary veins it goes into the left atrium. Then after going through the mitral valve, the blood is again pumped by the left ventricle this time through the aorta. This final pumping action results in pressuring blood flow throughout the body and returning it through the superior and inferior vena cavae into the right right atrium and through the tricuspid valve into the right ventricle and so on. This is what causes blood to flow (enter) the right atrium. That was my understanding after reading our articles. --hydnjo talk 04:56, 1 October 2005 (UTC) Strike my flawed response. --hydnjo talk 18:32, 1 October 2005 (UTC)

Then our articles are defective! The left ventricle doesn't supply the force that returns the blood to the heart. See [15], [16]. Mean circulatory pressure has no physical meaning as a driving pressure behind venous return. Normal Central Venous Pressure (though it can't be said to control venous return) is only about 2-6 mmHg. - Nunh-huh 07:23, 1 October 2005 (UTC)

I think the heart sucks, like this. I've seen toys that have liquid in a closed path, a one way valve and a rubber bulb. The valve keeps the flow in one direction and the bulb sucks the liquid in from the return path, even if there is no pressure on the return side. --JWSchmidt 20:04, 7 October 2005 (UTC)

Electron migration speed

When I close a switch to a circuit, someone down the line will be aware of that action at (nearly) the Speed of light. My question is, what is the speed of the individual electrons or what is the speed of electron migration as opposed to the signal speed? I hope I said it right, --hydnjo talk 01:27, 1 October 2005 (UTC)

You ask good questions<g>. This is a very complicated subject. See if this page is helpful. - Nunh-huh 02:55, 1 October 2005 (UTC)

This page (thanks Nunh-huh) is exactly what I was looking for. And also this (thanks SCZenz). My comments in the following paragraph have to do with something entirely different, I confused myself again. --hydnjo talk 19:52, 1 October 2005 (UTC)

I was inspired to ask this question from the query above: "Speed of light – where's the energy?" I think I found the answer at Current (electricity) which states that (electron migration speed) "in the near-vacuum inside a cathode ray tube, the electrons travel in near-straight lines ("ballistically") at about a tenth of the speed of light." The link above "(this page)" was also helpful but I was wondering about the speed of electron flow as a fraction of the Speed of light. That's what I was curious about. --hydnjo talk 04:05, 1 October 2005 (UTC)

Actually, I believe that in wires individual electrons are moving extremely slowly (a few cm per hour), and that the electrical signal, while much faster, still travels much slower than the speed of light. See here. -- SCZenz 06:01, 1 October 2005 (UTC)

My chemistry teacher used to quote 1 mm per second, but I don't know his source for that number. Ojw 18:04, 1 October 2005 (UTC)

• Sounds like the difference between wind speed and speed of sound. Thermal motion of electrons in a solid is random (due to collisions with solid) (cf. Brownian motion) but there is a net drift due to electric potential difference. Denote thermal speed as v_th. Denote average drift speed in the x-direction as $\langle v_{x}\rangle$ in centimeters per second: this speed is significantly smaller than v_th. Conductivity is inversely proportional to resistance. Conductivity σ is given by

$\sigma =qn\mu _{n}$

where n is electron density (number of electrons per cubic centimeter), q is electron charge (Coulombs per electron), and μ_n is electron mobility. Electron mobility is given by

$\mu _{n}=-{\langle v_{x}\rangle \over {\mathcal {E}}_{x}}$

where ${\mathcal {E}}_{x}$ is electric field in the x-direction in Volts per centimeter. Given a copper wire with a length of one meter, a diameter of one millimeter, and a potential difference of one Volt across it, then its electrons will drift at about 4.3 millimeters per second. The calculations are shown at the webpage hyperphysics.phy-astr.gsu.edu/hbase/electric/ohmmic.html#c2, which also offers good explanation. This kind of question probably falls into the category of solid-state physics. —AugPi 20:44, 7 October 2005 (UTC)

• Putting the above two equations together results in

$\langle v_{x}\rangle ={-\sigma {\mathcal {E}}_{x} \over qn}.$

Copper's conductivity is 5.88x10⁷ per Ohm-meter [17]. Potential difference in the given problem was stated to be 1 Volt per meter. Electron charge is 1.602x10⁻¹⁹ Coulombs. Copper's (free?) electron density is 8.47x10²⁸ per cubic meter [18]. Putting it all together:

$\langle v_{x}\rangle ={-5.88\times 10^{7}\left[{1 \over \Omega m}\right]\cdot 1\left[{V \over m}\right] \over 1.602\times 10^{-19}[C]\cdot 8.47\times 10^{28}\left[{1 \over m^{3}}\right]}$

$=0.004333{\left[{AJ \over VmCm}\right] \over \left[{C \over m^{3}}\right]}=0.004333{\left[{CCJ \over sJmCm}\right] \over \left[{C \over m^{3}}\right]}=0.004333{\left[{C \over sm^{2}}\right] \over \left[{C \over m^{3}}\right]}=0.004333\left[{m \over s}\right],$

since Ohm = Volt per Amp, Volt = Joule per Coulomb, Amp = Coulomb per second, the Joules cancel out, the Coulombs cancel out, squared meters cancel out, leaving meters per second. (The minus sign is here irrelevant.) So the answer is 4.333 millimeters per second, as stated. —AugPi 22:33, 7 October 2005 (UTC)

Capillary action and glass a couple small questions.

Hello. And thank you for your time first of all. Ill just cut to the bone.

I have found capillary tubes on the internet at .4 -.6 mm ID. What i would like to do is bend it about 120 deg. Actually i would like to bend sevral tubes together. The thing is im not to good at working with glass. If i were to heat the glass to the point i could bend it i fear i would collaps the id or at the least distort it to the point it would no longer work. With a copper pipe you can simply place a spring slightly larger than the OD of the pipe so as to hold its "roundness" as you make your bend. But with glass and being so thin to begin with i think i would have problems getting and keeping the glass hot enough withought being to hot to get a good bend. If possable i would like to bend say 20 tubes together and hopefully end up with extra capallary paths by default in the space between the tubes. But i also think bending more than one at a time would stretch the outer tubes or crimp the inner ones. And heating all evenly could be tricky.

My question is: How could i bend capillary glass and not destroy the id. And if possable how could i bend more than one at a time so as the bend is matched? How shallow of a bend would i need? And how could i bend more than one so that they could be stacked together close enough. Preferably a way i could do this in my garage without spending a ton of money. : )

Also all the searches i find on capillary action use water. I have read that water and glass is one of the best ways to observe capaillary action as they work great together. But i cant seem to find to much information on other liquids capillary properties. For example does mercury work well in a capaillary sence and what material tube would work well for that. It seems to have good surface tenssion. --68.42.226.224 01:41, 1 October 2005 (UTC)

Heated mercury can get into your bloodstream. It is a poison. The capillary action article indicates you are probably better off choosing another liquid besides mercury, as it would work in reverse. Ancheta Wis 11:56, 1 October 2005 (UTC)

what is a medicinal plant starting with ne

Well here is a start: Ne and then on to Nee and then finally to Nel. I hope it's in there somewhere. --hydnjo talk 04:18, 1 October 2005 (UTC)

Neem is a medicinal tree. --nixie 10:40, 1 October 2005 (UTC)

Category:Herbal & fungal drugs/medicines suggests Nettle. Thryduulf 10:51, 1 October 2005 (UTC)

Time problem

I'm taking the PSAT/NMSQT in a few days, so I need some help. How do you solve the problems that go something like "The clock above shows a time of 5:00. If the clock keeps accurate time, what time will it show exactly 125 hours later? --Neutrality^talk 04:30, 1 October 2005 (UTC)

This is a modular arithmetic problem. If it's 5:00 now, how many hours until the clock shows 05:00 the next time? Ans=24, or perhaps 12 depending on whether we're talking about a 12 or 24 hour clock. So the key is to realize every 24 (or 12) hours gets back to 05:00, so it's 05:00 24 hours later, and 48 hours later, and 72 hours later. The "in between" numbers are just like adding 1-23 hours to 05:00 but starting with a base that's the nearest multiple of 24 (or 12). What this is, is the remainder after dividing the total number of hours by 24 (or 12). 125 hours later is just like 5 hours later (remainder when dividing 125 by 12 or 24 is 5), so the clock says 10:00. -- Rick Block (talk) 04:43, 1 October 2005 (UTC)

125 = 12 * 10 + 5 (=24 * 5 + 5), so the clock will be 5 hours' ahead of its starting position, i.e. 10:00. You just have to look for convenient multiples of 24.

More generally, there's a lot like this in student math competitions, which sounds a bit like what you're doing. For example, the famous 17.5% VAT problem (take 10% by moving the decimal place, halve it to get 5%, halve that to get 2.5%, and add those 3 numbers to get 17.5%) -- it definitely pays to be sneaky and look for the shortcuts. Ojw 17:53, 1 October 2005 (UTC)

In addition, how does one solve problems like this quickly:

How many three-digit numbers greater than 240 can be formed by using three different digits from the set of {1, 2, 3, 4}?

--Neutrality^talk 04:39, 1 October 2005 (UTC)

For numbers greater than 300, you have the possibilities of '3' or '4' followed by any of the remaining digits, following by one of the remaining digits again. This is 2 ('3' or '4') x 3 x 2 = 12 possibilities. For the numbers between 240 and 300, you must select '2' as the first digit, then '4' as the next digit, and then there are two possibilites for the third, so you have an additional 1 x 1 x 2 = 2 results. Total result = 12 + 2 = 14. Most such problems are just a matter of multiplying out the possibilities, but in this case the constraints meant we had to break it into two problems.-gadfium 04:55, 1 October 2005 (UTC)

In general, the number of ways to order (permututate) X different objects is is X! (the factorial of X, i.e 1*2*3*4*...*X). For instance you can order A,B,C in 3!=1*2*3=6 ways(ABC, ACB, BAC, BCA, CAB and CBA). This is because you can select the first thing in 3 ways, the second in 2 ways, and the third in only 1 way, ie. 3*2*1=6 ways total. Hope this helps gkhan 11:32, 1 October 2005 (UTC)

You can start with 2 numbers (3,4). Then you have a choice of 3. Then you have a choice of 2. 2*3*2 = 12. Then notice a couple of possibilities you've missed (241,243). Total 14.

More generally, consider how much time pressure there is. If you can count the results quicker than doing a formula, write down the answer and move on -- multiple-choice tests don't give you any marks for an elegant solution applying formulas from permutation theory, but they often do reward people who can solve 200 questions per hour with reasonable accuracy. Ojw 18:02, 1 October 2005 (UTC)

statistics

What are the limitations of Statistics?

As in what? Prediction? ? Kieff | Talk 10:56, 1 October 2005 (UTC)

If you have a mathematical viewpoint, Statistics all looks like guessing and you can never be sure that you can depend on what you are looking at. (Statistics was first developed for Kings so that they could tax their realms more efficiently. Thus they didn't have to worry about exact answers.) But statisticians can give you the amount by which your guesses are likely to be wrong. Ancheta Wis 11:47, 1 October 2005 (UTC)

statistics is only as accurate as the data set that the statistis are based on. Also, they are subject to systematic bias, however there are tests for such bias, but correcting it usually involves adding another counteracting bias. However, if one knew the true values, then there would obviously be no need to do statistics. -Drdisque 20:48, 1 October 2005 (UTC)

I can't tell you with complete certainty. Ha ha, just a joke. Seriously, I was taught in High School the smallest usable data set is 10, below that you can't reliably get means or standard deviations from the data. JamesHoadley 15:34, 8 October 2005 (UTC)

I put the minumum useful sample more around 1100, which will provide a 3% margin of error over a 50% confidence interval. Less accuracy than that, say for a pre-election poll, would likely mean the poll's margin of error would be larger than any actual differece in the candidates' numbers. StuRat 08:04, 9 October 2005 (UTC)

Limit Definition of a Derivative

Find the slope of y=x+1/x at (5,26/25) using the limit definition of a derivative. (I can use the differentiation formulas, but the limit is what troubles me here.)

$m=\lim _{x\to 5}{\frac {x+{\frac {1}{x}}-{\frac {26}{25}}}{x-5}}$.

This reduces to $m=\lim _{x\to 5}{\frac {25x^{2}-26x+25}{25x\times (x-5)}}$. As you see, the numerator of the second limit is prime; I can't evaluate the limit because of the (x-5) in the denominator.

Please help me.

--Henry

$m=\lim _{x\to 5}{\frac {x+{\frac {1}{x}}-5-{\frac {1}{5}}}{x-5}}.\ \mathrm {Next} ,m=\lim _{x\to 5}{\frac {(x-5)+({1 \over x}-{1 \over 5})}{x-5}}$.

Now cancel the (x-5)s out of every term in the expression on the right.

Therefore,$\lim _{x\to 5}(1-{1 \over 5x})=1-{1 \over 25}={24 \over 25}.--Henry$

(added after edit conflict)

First off, it's not 26/25, it's 24/25 :P

It was a coupl of years since I done this, but oh well :P. You're limit definitition is all wrong. The definition of a derivative of a function f(x) is

$f'(x)=\lim _{h\to 0}{\frac {f(x+h)-f(x)}{h}}$

which becomes

$f'(5)=\lim _{h\to 0}{\frac {5+h+{\frac {1}{5+h}}-(5+{\frac {1}{5}})}{h}}$

which simplifies to

$f'(5)=\lim _{h\to 0}{\frac {24-5h}{25-5h}}$

Cheers gkhan 07:43, 1 October 2005 (UTC)

There are two definitions of the derivative. You've each written one of them. -- SCZenz 19:25, 2 October 2005 (UTC)

Wha? Look, last time I checked this was still the ENGLISH Wikipedia! Take your strange language to http://math.wikipedia.org/wiki/ --inks 10:36, 1 October 2005 (UTC)

d00d! y00 suxz! m4th is teh l337 :D gkhan 11:20, 1 October 2005 (UTC)

TV on the computer monitor

I am wondering if such equipment exists that'll put (cable) Television onto my desktop computer monitor. I am not talking about streamed TV over the internet, I want to somehow plug my monitor and speekers into the TV cable line. To do this I would need a cablebox (to change channels), are there any that can connect to my Monitor?

I apologize if my question is badly written, I am tired. -anon

You can't do it without a peripheral card in your PC that accepts your television standard. Right now the TVs that can also serve as computer monitors cost more than bottom of the line PCs. You won't save any money at the moment. This is not an accident. Ancheta Wis 11:38, 1 October 2005 (UTC)

If you already have a video card that will accept Video/Sound Out (or even SCART) somehow, it would just be a matter of connecting it to the right outputs on the cablebox. Have I missed something here?--inks 23:48, 1 October 2005 (UTC)

There is something called an LCD TV which will accept TV connections. If your video card has RCA/S-video in then you can get limited TV support. Your best bet is getting a TV tuner card, they can usually found for about 30-40$

Normalization of scale

How normailzation of scale is done before performing data anlysis.

First find the largest number in the data set. Then divide your results by that number. Be sure to state that number in your displays. Ancheta Wis 11:34, 1 October 2005 (UTC)

Normalization of scale

Is it necessary to perform normalization of data before data analysis.If so how normailzation of scale is done before performing data anlysis.

sandeep

This depends on what sort of data you are working with, and what sort of information you wish to extract from it. What sort of data are you working with? You might, say, use the standard deviation of the data set as a relative measure if it is finite. You might also want to read nondimensionalization too. --HappyCamper 20:04, 1 October 2005 (UTC)

planets

Planets? ? Kieff | Talk 16:40, 1 October 2005 (UTC)

• Planets!!! Rofl, what is the question?--172.208.123.70 13:54, 2 October 2005 (UTC)

what is dsl?

I suppose you mean Digital Subscriber Line? ? Kieff | Talk 16:40, 1 October 2005 (UTC)

DSL can also mean Damn Small Linux. There is a good article on DSL though.

Aluminum can alloy

It says in the magnesium article that it is a component in aluminum soda cans. I can't seem to find any other sources that agree with that. Can anyone verify/disprove that?

what is epidemiology

see epidemiology. Thryduulf 17:27, 1 October 2005 (UTC)

Periodic Table

What is an element that I can see as a soild, liquid, and gas?

Since all solids and liquids distort light enough for you to "see" that something is there, any element that is colored as a gas would fit your criteria. Chlorine is an example but I am sure there are others. alteripse 20:58, 1 October 2005 (UTC)

• Bromine or iodine. Physchim62 10:23, 2 October 2005 (UTC)

what is an catalytic antibody

It's an antibody with catalytic properties, duh... pay attention during your lectures... you specifiy an antibody to mirror the properties of a biological molecule with catalytic activity, usually some sort of enzyme... then you have an analog of an enzyme reactive site that you can target to specific tissue types... try here Catalytic Antibody if it exists--172.208.123.70 13:52, 2 October 2005 (UTC)

Off-Label Use; FDA Application for

Am advised that before a clinical study utilizing an 'already approved' medication (to kill a newly discovered microorganism) will be 'monitored' by a medical Institutional Review Board (IRB) – an application for its (the medication's) "Off-Label Use" must have been submitted to the FDA.

A means of potentially eliminating the No. 2 killer, heart disease, (including stroke, TIAs, carotid artery blockage and other cholesterol related vascular disease) has been discovered and utilizes a well known, broadly used antibiotic to kill the microorganism that causes vascular plaque buildup and other 'unwanted calcium' related conditions.

Can you tell me the procedure for filing such an application with the FDA – for "Off-Label Use" of a medication and where I can find a copy of the application form?

Thank you.

Moving this unsigned question here from the Helpdesk--inks 23:38, 1 October 2005 (UTC)

Most likely, your IRB is requiring you to submit an IND (Investigational New Drug) or NDE (New Drug Evaluation) application with the FDA [19] because your study does not qualify for a waiver. If you don't already know how to do this, you need help from someone who has experience with the process. It's not a task for the weak-hearted, and it can't be done on the basis of advice from Wikipedia! You can start by asking your IRB for additional information. You might also have a look at the FDA site. (I'm assuming you know about previously conducted studies which have failed to show benefit from antibiotics with regard to plaque; (2 studies were published in the April 21 2005 issue of the New England Journal of Medicine) – you'll need to include a literature review in your application.) [20] – Nunh-huh 01:30, 2 October 2005 (UTC)

You pick up the telephone and you call your hospital's IRB. You have to take a several hour course on ethics of human research in order to be a principal investigator for a research project involving people. Then you have to write up a description of your trial (the protocol) and a sample informed consent form. Then you make an appointment to present it to your hospital's IRB at one of their regular meetings. Be prepared to discuss relative risks and some skeptical questions if you are planning to offer your experimental treatment instead of a standard treatment. Remember, part of ethical resarch is designing a study that will have the power to provide a useful answer for the time, trouble, and potential risk of the subjects. What trial design did you have in mind? What recruitment method-- your patients, newspaper ad, referrals? I suspect I am not the only one who thinks anyone who is asking wikipedia how to do medical treatment research is pretty unlikely to know what he is doing or have the resources to do it, but we'll be happy to tell you the procedure. alteripse 01:49, 2 October 2005 (UTC)

Maybe, maybe not, but Wikipedia is already doing a service by pointing out what the procedures (and safeguards) are for those of us who will never actually conduct this research ourselves (but who might one day be invited to be a subject of it). Thanks to the knowledgeable contributers! Physchim62 13:58, 4 October 2005 (UTC)

convert 1 kilometer to miles

convert 1 kilometer to miles

The easiest way to perform these converions is to use Google – just type 1 kilometre in miles into the seach box, click "search", and you will get the result: 1 kilometer = 0.621371192 miles. Thryduulf 11:00, 2 October 2005 (UTC)

Molecular Biology Techniques / PCR

What is the use of Nonidet P40 or Tween 20 etc. detergents in Polymerase Chain Reaction?

AA

For samples that contain cells, a detergent will make the target DNA accessible by dissolving cell membranes. --JWSchmidt 20:12, 7 October 2005 (UTC)

Xenon

What are the main properties of Xenon? <--- click here

Have you looked at our Xenon article?-gadfium 07:46, 2 October 2005 (UTC)

neurons

can neurons regenerate? - anon

• Very slowly and as far as I know only in young people. Perhaps our article on neurons has some more useful info or links. - Mgm|^(talk) 11:06, 2 October 2005 (UTC)

Very hot area of research. There is now evidence that regeneration can occur in many types of human neurons, and even in adults, against general beliefs from observation of neuroscientists and doctors for most of the last century. You can find articles by searching medline or pubmed for "nerve regenertation". Even googling it gets lots of hits. alteripse 01:22, 3 October 2005 (UTC)

People often ask this in the context of re-growth of cut axons. In the PNS axons often grow back. In the CNS there is often scar tissue formation that blocks re-growth. --JWSchmidt 20:22, 7 October 2005 (UTC)

bermuda triangle

Perhaps you are looking for our Bermuda Triangle article? Thryduulf 10:57, 2 October 2005 (UTC)

SNP

what is SNP

To me it means the Scottish Nationalist Party, but the the SNP page gives several other uses as well. Thryduulf 13:50, 2 October 2005 (UTC)

How do the tiny flaps of gills enable the fish to absorb as much oxygen as possible?

Please tell me ASAP.Tdxiang 13:22, 2 October 2005 (UTC)

See Gills. Thryduulf 13:48, 2 October 2005 (UTC)

3D Shape Problems

what is the "End Area" of a 3d shape, can someone explain this term and also how do you find the End area of a Cuboid, triangular prism and cylinder? Also can someone please explain to me how do you find the width of any 3D shape? can someone please help me?

regards nmak3000

In general there is no such thing as the 'end area' of a 3D shape. However all the shapes you mention are examples of prisms (in the mathematical sense). Have a look at the definition. The end area of a prism is probably the area of the end, i.e. its cross-section. DJ Clayworth 15:51, 3 October 2005 (UTC)

Activation of Windows XP

Suppose you have an old computer, and you had to reinstall windows, but suppose you don't know where your activation code is??? Is there anyway to extract that information from the computer itself?? Or are you just out of luck, and have to go buy a new installation disk from microsoft?

Hmm, maybe this could help somehow: http://www.annoyances.org/exec/show/article03-200 ? Kieff | Talk 17:15, 2 October 2005 (UTC)

Are you looking for the Key Code? Because if it's not too old, then it should be on your Tower(CPU) and it should be green, and silver, If it's a Laptop then it might be under it, and be green and silver.

Hope this helps Lordned 16:39, 3 October 2005 (UTC)

This little program will do the trick: [21]. It gets your Product Key and even lets you change it if you want. It works on all versions of Windows. Enjoy. --pile0nades^{talk | contribs} 04:06, 5 October 2005 (UTC)

What are the cultural/ethnic considerations of clients with ESRD?

I'm not sure exactly what you mean by your question, but perhaps you can find some info at Chronic renal failure.

Dental polymers

I'm trying to find information on the use of polymers in denistry, but I'm unable to find any such information on either the Polymer or Denistry pages on Wikipedia. Any suggestions/information?

-Josh/Sycron

• See Dental fillings. --jpgordon∇∆∇∆ 20:37, 2 October 2005 (UTC)

Deriving a logarithm series

How would one go about deriving the following logarithm series expansion?

ln((1+x)/(1-x)) = 2(x + (x^3/3) + (x^5/5) ... )

Thanks in advance! This has been bugging me all day!

This one isn't too bad, but it takes a couple of steps. Bear with me. Oh, and we'd better assume $x\in (-1,1)$. Now, then, first it'll help to split up the problem as follows:

$ln({\frac {1+x}{1-x}})=ln(1+x)-ln(1-x)$

Now we'll work on the second term, and later get the first from it. First, note that

${\frac {1}{1-x}}=1+x+x^{2}+x^{3}+...$

(To see this, just multiply both sides by 1-x.) Now integrating both sides from 0 to x gives:

$-ln(1-x)=x+{\frac {x^{2}}{2}}+{\frac {x^{3}}{3}}+{\frac {x^{4}}{4}}+...$

From this, replacing x by -x, we get

$ln(1+x)=x-{\frac {x^{2}}{2}}+{\frac {x^{3}}{3}}-{\frac {x^{4}}{4}}+...$

Which going back to the first equation gives

$ln({\frac {1+x}{1-x}})=(x-{\frac {x^{2}}{2}}+{\frac {x^{3}}{3}}-{\frac {x^{4}}{4}}+...)+(x+{\frac {x^{2}}{2}}+{\frac {x^{3}}{3}}+{\frac {x^{4}}{4}}+...)=2(x+{\frac {x^{3}}{3}}+{\frac {x^{5}}{5}}+...)$

Hope that helps! -- SCZenz 20:40, 2 October 2005 (UTC)

ATP (adenosine triphosphate)

Since ATP is the direct source of energy for body cells, why not bypass the lengthy digestion and cellular metabolism process for carbohydrate breakdown and eat ATP directly?

• because, if you ate it, it would pass through your digestive system and well, be digested, same thing with just about all your cellular components, you have to synthesize your own--172.208.123.70 21:39, 2 October 2005 (UTC)

It also costs thousands of times more than sugar or starch. alteripse 22:39, 2 October 2005 (UTC)

Mammalian metabolism tends to convert most dietary nutrients into the simple sugar glucose before it degrades it and captures the chemical energy as ATP (via NADH + H+). Hence a drink containing glucose is a perfectly acceptable way to provide the body with an energy precursor. I suppose it beats an iv injection of ATP !

Taylor series expansion in x-a

How would one expand $g(x)=sin(x)\,$ in powers of $x-pi\,$? I have the solution to this, but I haven't been able to get there on my own. Any expanation with steps would be appreciated! Thanks!

Try letting $y=x-\pi ;\,$, then using $sin(x)=sin(y+\pi )=sin(y)cos(\pi )+cos(y)sin(\pi )=-sin(y)\,$. Then do the usual expansion about $y=0\,$, and substitute back in what y is. Does that work? -- SCZenz 23:15, 2 October 2005 (UTC)

When in doubt, you can always go back to the most general definition of a Taylor expansion near $''x''=''a''\,$:

$f(x)=f(a)+f^{\prime }(a)(x-a)+{\frac {1}{2}}f^{\prime \prime }(a)(x-a)^{2}+\ldots {\frac {1}{n!}}f^{n}(a)(x-a)^{n}+\ldots$

Notice that this expansion is what you want for a = π and f(x) = sinx. Then

$f(\pi )=\sin \pi =0\,$

$f^{\prime }(\pi )=\cos \pi =-1\,$

$f^{\prime \prime }(\pi )=-\sin \pi =0\,$

$f^{3}(\pi )=-\cos \pi =1\,$

$f^{4}(\pi )=\sin \pi =0\,$

Now we can see a pattern: these values of the derivative will simply repeat, and the Taylor series will be:

$\sin x=-(x-\pi )+{\frac {1}{3!}}(x-\pi )^{3}-{\frac {1}{5!}}(x-\pi )^{5}+{\frac {1}{7!}}(x-\pi )^{7}\ldots$

Which matches exactly the expansion of -sin(x - π), which is what you get with SCZenz's method. — Laura Scudder | Talk 23:34, 2 October 2005 (UTC)

glass that shifts from translucent to transparent?

I was wonderin what the type of glass that shifts from translucent to transparent is called. I am an currently designing my own house and am looking to include it in my plans. It is a glass that appears to be clear but when a switch is turned or the door it is made of is closed it becomes much like frosted glass, I have to assume that this is electrically induced, but you know what they say you do when you assume. An example os this the bathroom stall doors in the "Real World: Austin" house. I would greatly appriciate a name and if possible the website of the company that produces it. Thank you very much for any help.

70.22.39.248 23:20, 2 October 2005 (UTC)John

One would think they just stick a lightsource of some kind behind the glass, which allows it to change from transparent to opaque at the flip of a switch, probably normal glass would do--172.208.123.70 23:27, 2 October 2005 (UTC)

Actually, they are special materials (and a large window can cost as much as a human kidney on the black market!). Unfortunetly, our article on the subject is just a stub: Electrochromics. ? Kieff | Talk 00:11, 3 October 2005 (UTC)

what are possible health effects of drinking diet soda?

I already know how bad regular soda is (high calories, high sugar), but I don't know about any negative health effects of diet soda yet. Are there any? --Revoluci n (talk) 23:56, 2 October 2005 (UTC)

I think this might interest you: health effects of aspartame ? Kieff | Talk 00:13, 3 October 2005 (UTC)

Kieff seems to have it right, I was thinking of phenylalanine, but apparently aspartame is the compound based on that which is found in most 'diet sodas'. I remembered that on Coke cans here in Australia, they warn of the presence of phenylalanine.. perhaps Diet Coke may be useful to you? splintax ^(talk) 03:58, 3 October 2005 (UTC)

I believe that most sodas are moderately acidic, even the diet varieties, and the acid will destroy tooth enamel. See [22].-gadfium 01:22, 3 October 2005 (UTC)

I recall reading that some diet pop shipped to Arabia for the troops there was left out in the heat for an extended period and started changing into a nerve toxin slowly.

I'm pretty sure that was Methanol. I doubt our reader will be leaving his pop in the middle of a desert though. --Phroziac^(talk) 14:35, 4 October 2005 (UTC)

Diet soda has more caffiene then regular. --Phroziac^(talk) 14:35, 4 October 2005 (UTC)

Don't forget loads and loads of sodium, at least in many diet drinks.Brian Schlosser42 19:41, 5 October 2005 (UTC)

what are the four classes of organic compounds?

See Organic chemistry. The four classes would probably be Aliphatic, Aromatic and Heterocyclic compounds, and polymers. Although you might want to edit your question to be a bit more specific. splintax ^(talk) 03:54, 3 October 2005 (UTC)

what is miasma?

A very pejorative term for mist, or something bad suspended in the atmosphere. Among the politically correct, "special air" is now considered preferable. alteripse 01:05, 3 October 2005 (UTC)

Geometry Area or a Square

What is the area of the square ABCD that has a diagonal of length 12 cm?

See pythagorean theorem, and note that a square is just two right triangles. -- SCZenz 01:24, 3 October 2005 (UTC)

More specifically, two isoceles triangles. --jpgordon∇∆∇∆ 03:09, 3 October 2005 (UTC)

I know I'm doing this person's homework for them, but just to clarify – I'll solve the problem. Squareness implies that all sides are equal in length. From Pythagoras' theorem we get:

$a^{2}+b^{2}=c^{2}$

Since c is the length of the diagonal (or the hypotenuse of the triangle inside the square), and a = b (because they are sides of a square), we can say:

$a^{2}+a^{2}=12^{2}$

$2(a^{2})=144$

$a^{2}={\frac {144}{2}}=72$

We could find the square root of 72 to find the side length of the square, but keep in mind that the area of the square is simply the side length squared. Therefore, the area of the square is 72. splintax ^(talk) 03:49, 3 October 2005 (UTC)

Hair texture

Humans evolve different traits according to their environment. For example, people who originated in places close to the equator tend to have darker skin, because it has more melanin and protects them from the sun and skin cancer. Why do black Africans (and I have also heard New Guineans and possibly other people that I don't know about) have curly hair that is so different from most other people who have straight hair (what environmental or other factors led them to develop this type of hair and why was it an advantage)? --KForce>(talk)</ 05:39, 3 October 2005 (UTC)

Did you read Hair? This quote may be helpful:

The diameter of a human hair ranges from about 18 µm to 180 µm. In people of European descent, blond hair and black hair are at the thinner end of the scale, while red hair is the thickest. The hair of people of Asian descent is typically thicker in diameter than the hair of other groups.

Cross-section shape of human hair is typically round in people of Asian descent, round to oval in European descent, and nearly flat in African peoples; it is that flatness which allows African hair to attain its frizzly form. In contrast, hair that has a round cross-section will be straight. A strand of straight round cross-section hair that has been flattened, for example, with an edge of a coin, will curl up into a micro-afro.

Hope that helps, although it doesn't answer your question completely. splintax ^(talk) 03:51, 3 October 2005 (UTC)

Now there's a nice eurasian-centric way of putting the question. Ever heard of the out of Africa theory? I assume we all had nappy hair once upon a time, but those who left Africa somehow lost that (I don't know why, though, sorry). Note that pubic hair also curls because it is flat. One might conclude that blacks have pubic hair on their heads, but it would make more sense to say the rest of us still have nappy crotches :) . DirkvdM 14:11, 3 October 2005 (UTC)

Ok, I am very familiar with the out of Africa theory, and perhaps I asked the wrong question because I agree, that was a very eurasian-centric way of putting it. Ok, so going from an out of Africa view, why did people from everywhere else develop straight hair where the shape of the hair is round, rather than curly hair where the hair is flat? --KForce(talk) 16:00, 3 October 2005 (UTC)

One possibility is that a variety of hair textures serves simply to help identify people. Different eye color, for example, doesn't appear to serve any purpose other than to aid in identification. There might be biological advantages to some hair textures over others in each environment, as well. A large "afro" would be good in hot weather, as the heat would be created when light strikes the hair far from the scalp, and thus would limit heating of the brain. In cold whether, hair that lies flat may be better, allowing more of the heat to transfer to the brain. StuRat 07:43, 9 October 2005 (UTC)

can birds fly in vaccum

No. See aerofoil and bird flight. Guettarda 05:28, 3 October 2005 (UTC)

Not to mention that birds breathe. -- Jmabel | Talk 05:29, 3 October 2005 (UTC)

What about in free fall, I wonder if any birds have been taken to orbit? --WhiteDragon 16:56, 4 October 2005 (UTC)

I guess nobody knows, but it would probably be very confused. A bird in zero-gravity would probably experience that it were falling, but it would feel no wind and probably have no feeling of up and down. It might try to fly in the direction it would percieve as "up", perhaps changing direction all the time. Or it might simply sit (or float) still. It would definitely have a hard time trying to maneuvre. It would be very interesting to see if a bird could adapt to zero-gravity conditions.

Not to mention that their loungs, blood vessels etc. might break or even explode because of the low pressure in a vacuum.

Actually, I remember reading at one point that NASA scubbed a part of a mission that was to include taking birds into orbit. Birds lack the muscles in their necks necessary for peristalsis, so they would have died from dehydration/starvation. Guess we'll never know. --Michael 04:22, 9 October 2005 (UTC)

blood vessels in eyes

When you look at a human eye, there is the inner part which is colored and the surrounding area which is white. However in the white part of your eye, you can often see red blood vessels. It appears that sometimes you see more of them than other times (when there are a lot of them, I think it's called blooshot eyes?) What causes these blood vessels to appear more at certain times, is it a sign of an unhealthy eye, and what can be done to prevent lots of blood vessels from appearing or to make visible ones go away? --KForce 05:38, 3 October 2005 (UTC)

Many reasons, one of which is Conjunctivitis. --hydnjo talk 06:00, 3 October 2005 (UTC)

Your body has the ability to have each blood vessel and capillary contract or expand as needed. Only those close to the surface are visible, however, causing blushing and bloodshot eyes, for example. One should be careful to distinguish between cause and effect here. Some irritation or infection of the eye creates a need for increased blood flow to bring white blood cells, etc., to the area to repair the damage. So, bloodshot eyes aren't the "disease", they are the "cure". It's true that they are unsightly, but it's best to leave them bloodshot long enough to fix the problem rather than using a product which will cut off the needed blood supply (the most famous being "Visine – gets the red out"). Of course, identifying the source or irritation, such as smoke, lack of sleep, eye strain, etc., and eliminating it, will be best in the long run. StuRat 07:29, 9 October 2005 (UTC)

What is analog telephony and its chief concepts?

Looks like a homework question (do your own). Telephony is that which is based on or related to telephone communication, and analog is not digital. That said, check out Category:Telephony and the "See Also" section of the Telephone article. — Lomn | Talk / RfC 15:01, 3 October 2005 (UTC)

Tired legs

I know this may not be the best place to ask this question, but before going to a physician I wanted to hear your opinion. I'm a 19 year old frequent sportist (mostly upper body strength, rarely cardiovascular exercise) and, since this summer when, after playing more than 2 hour long everyday soccer matches I've been experiencing lack of strength and sometimes even pain after doing basic leg exercises, such as running or jumping. Do you have any idea of why can be this happening? PD: Sometimes, while on computer, I experience a tingling sensation in my legs.

Thank you in advance.

Seems like a normal excercise pain to me. I'm pretty sedentary myself, and I get the same simptons whenever I ride a bike for a few kilometers or play soccer for an hour or two. But I'm no physician, so remember Wikipedia:Medical disclaimer. ☢ Kieff | Talk 11:36, 3 October 2005 (UTC)

A medical discalaimer on Wikipedia?? Get real! Anyone who thinks that Wikipedia can serve as a substitute for a physycian really needs to see a doctor – just of a different kind :) . DirkvdM 14:41, 3 October 2005 (UTC)

The differential diagnosis for this symptom is lengthy and ranges from trivial to slowly catastrophic. See a doctor but before the visit try to think of objective evidence for a real change (e.g., substantial difference in how far you can walk, bicycle or climb stairs compared to 6 months ago) rather than subjective differences (I feel more tired when I...). Second, think about whether this is just a leg problem, or leg and foot, or whole body strength change. Third, your doctor will be trying to distinguish between subjective versus objective weakness, earlier fatigue versus decreased strength, localized versus generalized weakness, strength only changes versus strength plus changed sensations. Fourth, think about any other new symptoms or body changes, especially those present for the last few months. Good luck. And for the potential hypochondriacs out there in audienceland, I would like to emphasize that purely subjective changes in strength and energy rarely signal serious disease.alteripse 16:21, 3 October 2005 (UTC)

reasons for hair loss for male in the age group of 18 to 20

See alopecia. Differential diagnosis depends on pattern and degree of loss (i.e., visible bald areas versus more hairs in the shower drain or brush) and ranges from perception to normal androgen effect which will culminate in male pattern baldness to a variety of less common causes of localized hair loss to (rarely) some systemic (whole-body) diseases of metabolism or nutrition. Good luck. alteripse 16:27, 3 October 2005 (UTC)

If you join the military, you will get a hair cut. There are military reasons why short hair desired: uniform standardization; in hand to hand combat, more difficult for enemy to grab you by the short hairs. AlMac|^(talk) 03:37, 5 October 2005 (UTC)

the line between night and day

Is there a name for the boundary of the shadow that turns night into day? I thought there was, but it's not mentioned in either article. -Lethe | Talk 15:30, 3 October 2005 (UTC)

I believe it's most commonly called the terminator. — Lomn | Talk / RfC 15:34, 3 October 2005 (UTC)

acre as distance between gas wells

It is said that the distance between gas well drilled in the Barnett Shale in Texas must be twenty acres. If an acre is a measure of area, how is the distance between these wells determined?

<email removed>

You shouldn't put your email on this page, as everyone in the world will read it and send you spam. Replies will be posted on this page, not to your email address.

Probably this means that every gas well should be on a piece of land of twenty acres without another well on it. Givng the separation this way allows for easy calculation of how many wells you can put on a piece of land. DJ Clayworth 15:45, 3 October 2005 (UTC)

On the other hand, it doesn't prevent you having your twenty-acre plots be very long and skinny, and putting your wells ten feet from each other in a row. I think official idiocy is the real reason. PeteVerdon 11:42, 7 October 2005 (UTC)

C++ tutorials?

Can someone give me a link to a free, online, C++ tutorial, that starts from the very basic? Or some tips abouat C++

Any help appreicated Lordned 16:35, 3 October 2005 (UTC)

PS. Does anyone know what "Iostream" means?

It's Input/Output Stream, one of the basic I/O libraries for C++. — Lomn | Talk / RfC 17:22, 3 October 2005 (UTC)

I'd recommend "Thinking in C++" by Bruce Eckel, available at www.mindview.net. It's for people who have some experience of programming in any other language; if you've never programmed in anything, then I wouldn't recommend C++ anyway.-gadfium 21:54, 3 October 2005 (UTC)

Well i have the basics of C++ down. Took a week long class, at a camp.

 -Lordned

how the length of a wire affects its reesistance

It's linear. — Lomn | Talk / RfC 17:23, 3 October 2005 (UTC)

Resistance of a wire = (length * resistivity) / cross-sectional-area →Raul654 19:12, 3 October 2005 (UTC)

What are the Dymanics of Smoke?

Does it rise? Fall? Disperse? etc.

Well, obviously it rises first (ceterus paribus), but I suppose you mean after it has cooled down. And I suppose that depends on it's chemical structure, but I'm pretty sure that most smoke particles are heavier than air and will therefore fall. If neither shaken nor stirred, that is, and for that you'd need laboratory circumstances. Otherwise they'll just float about until they stick to something I suppose. Not that I actually know, by the way.... :) DirkvdM 18:55, 3 October 2005 (UTC)

Light Filtering

Is it possible for a static light filter in the form of a single piece of glass, lexan, polycarb, etc. to defer brighter light in greater proportion than softer light? I am asking specifically regarding applications in vision augmentation like sunglasses or larger shields, interested in knowing if a specific filtering process is better or worse for high-light/low-light situations. I know about LCD based active filters, and various aspects of polarized filtration, neither of which are exactly what I'm interested in. TIA! --Jmeden2000 17:29, 3 October 2005 (UTC)

• No truly static device can do what you want. A saturable absorber (man, that's a bad article) is the closest in concept. Generally, this sort of thing is called an "optical limiter" and there are various organic dyes that work this way, with various drawbacks. I know at least one brand of sunglasses (Reactolite Rapide) that used them. -- Bob Mellish 17:49, 3 October 2005 (UTC)

• • Damn, that article was crappy. I had to tweak it a bit, it looks like a proper thing now. I also redirected to the appropriate location. ☢ Kieff | Talk 17:58, 3 October 2005 (UTC)

• • • Actually, I had a braino there. A saturable absorber is exactly the opposite of what the OP wanted. An optical limiter is correct (increasing absorption with increasing intensity). Still, thanks for sorting out that stub, which it sorely needed. --Bob Mellish 18:07, 3 October 2005 (UTC)

Stress fracture

You're not wrong. See Stress fracture. Proto t c 13:28, 4 October 2005 (UTC)

what causes food decay

Any of a variety of bacteria and fungi spores commonly present in the air start digesting the food, and it degeneratres (as well as the bacteria and fungi themselves not being very edible). --Borbrav 00:33, 4 October 2005 (UTC)

Aerodynamics of Birds

hi,

   I am entering a scince fair and I need a few pictures of wind diagrams of bird wings!

                    ,--Jake Haines 18:51, 3 October 2005 (UTC)

2 Windows Xp os'

OK, I'm sure the title could have been a little more descriptive, but... here's my situation:

I have 2 XP's loaded on my hd for some reason, at start-up i get the screen to select which one to boot from, one works, the other doesn't. How to I get rid of the one that will not boot? I want to get it of my hard drive all together, how would I go about doing that?? john

I am new to this Wiki site,

But I may be able to point you in the right direction with regards to your double os selection.

You can remove the non-working option from the start up by editing the system start up file. One way to do this would be to right mouse click on My Computer, goto properies, select the Advanced tab, click on the settings tab under Startup and Revovery. Now you will have the option to Edit the start up options manually by clicking the Edit button. This will open up a text document with the operation systems listed here. As for which one to delete I cannot remember please seek further help on what to do next Be warned I am sure that if you delete the wrong line your system will not boot because you will be left with the system that doesn't work. There is probably more information about this but I hope this helps.

Gezzabob 22:26, 5 October 2005 (UTC)

Difference between "Applications" and "Services" Concepts in Computer Science

Many organizations are adopting Service Oriented Architectures (SOAs) to increase interoperability and software reuse. Software developers used to refer to their products as "Applications". With the new "Services" approach, is there an agreed upon definition/distinction/relationship between the terms "Application" and "Service"?

Carl Prantl

An application is a piece of software, a service is the task that that application performs. Think of it this way – TCP/IP is the application, but the service it provides is reliable data transfer across a network. →Raul654 19:10, 3 October 2005 (UTC)

I believe their is a different business model behind the two terms. If your group supports a certain "application" that implies they are tied to a strict set of software, whereas if they support a "service", they may be more flexible, by developing their own software, contracting out that development, or using off-the-shelf products to provide the same service more efficiently for less money. StuRat 07:16, 9 October 2005 (UTC)

Why are most metals cold to the touch?

I understand because they conduct heat away more efficiently than other materials, but is there a more scientific explanation for this? - Cobra Ky (talk, contribs) 19:11, 3 October 2005 (UTC)

That's pretty much it, as far as I know. If a metal is colder than your skin, it conducts heat away faster and feels cold; if it's warmer, it conducts heat to you faster and feels quite warm. Also, metals cool down (and warm up faster), so they may actually be cooler (or hotter) than other objects if there's been a recent temperature change. If they have direct sunlight on them, of course, they absorb that energy quite efficiently and become very hot. -- SCZenz 19:44, 3 October 2005 (UTC)

Thanks for your swift answer. But what is it ABOUT metal that makes it conduct heat faster? What is it in the chemical composition that causes this? - Cobra Ky (talk, contribs) 19:50, 3 October 2005 (UTC)

The atoms in a metal are close together and strongly bound to one another: for most metals, the atoms are packed as closely together as possible. Vibrations of one group of atoms are rapidly transmitted to the other atoms in the object (this is how heat, and sound, are conducted). The links between individual molecules in, say, wood or plastic are weaker and the transmission of vibrations is less efficient: hence their thermal conductivity is lower. Physchim62 20:26, 3 October 2005 (UTC)

Ah ha! Thanks, that makes perfect sense. - Cobra Ky (talk, contribs) 21:12, 3 October 2005 (UTC)

I think that electron structure is probably more important for explaining thermal conductivity than bond strength. Atomic bonds in metal are not particularly strong, so that explanation needs some work. See thermal conductivity for more on the subject. Apparently it's a complex question. -Lethe | Talk 00:00, 4 October 2005 (UTC)

Eye fatigue

Can being in front of a computer screen (2 feet from screen) damage your eyes if used for an extremely long time? any difference between LCD and CRT screens?

Probably not permanent damage. It can definitely cause strain and discomfort, however. Remember that your doctor, not Wikipedia, is the best place to go for medical advice. User:Nightvid

I'm no expert, but here's what I think I know. I can think of two reasons an LCD would be safer than a CRT. One is radiation, of which an LCD doesn't transmit any, afaik. CRT's are shielded somehow and there will likely be big differences between different screens. I'm surprised to see the manual to my monitor doesn't give any info on that. Just that it's TCO'99 compliant. Alas the TCO Certification article is just a stub and I haven't found a better source just yet. The other thing is the strain Nightvid mentions, which I believe is caused by flicker, which at least partly has to do with the refresh rate a monitor can handle. This you might measure by using a screen for a whole day. If that doesn't give you a headache it's probably a good screen. LCD's have a slow reaction, which is bad for gamers but good for your eyes. And just as too much reading (with bad light and such) can be bad for your eyes, I suppose this can have a permanent effect.

By the way, is a doctor the best source for info in this? It's not about a specific personal ailment but about something general, so there should be some general info somewhere. I just don't know where. DirkvdM 09:23, 4 October 2005 (UTC)

I not know the correct terminology for some of this, but

you can get a prescription from the eye doctor to optimize your vision for a particular distance, like how far your head is normally from computer console (which is different for me at home and at work)

I think the current monitor standard is SVGA ... anyhow I went with a higher standard because the bigger the screen and the smaller the pixels the crisper the image, and on some OS you can adjust the size of the characters (think how many characters sideways and how many vertical) ... so basically it is like looking at a good book, or a fuzzy picture, or some place in between.

Look at telephone yellow pages ... black print on yellow background is easiest to read, but what about what is around what you looking at ... the entire vision contrast impacts usability or readability.

What kind of lighting do you have? You want to avoid any glare on the screen If you are in an office, often there are those blue lights in long translucent tubes (I forget the name ... fluorescent?) anyhow depending on where they are relative to your monitor, their flicker rate can interact with the computer monitor flicker rate to the detriment of your vision. Ideally you want to be positioned so that they run down the side of your work area paralleling the direction that you are looking in. You do not want them directly overhead of you or your monitor. You do not want to be sitting with them side to side relative to your desk. Typical work place you not have a choice in matters of ergonomics.

(and does it need cleaning?) When I get in my auto sometimes my glasses are misted up, and sometimes the windshield is misted up, and I need to wipe both sides of both to get a clear unfuzzy image ... well your computer monitor is like that, only simpler.

Also review keyboard and seating. Is your hand at a comfortable height? Are you keying kind of hunched over, so you get back pain? Are you keying so your hands are uncomfortable ... do you know what causes carpal tunnel syndrome? I think heavy use of mice contributes a bit to this.

Some Internet sites are designed so as to be hostile to some users. For info on this problem with some Wiki pages, see Wikipedia:WikiProject Usability.

AlMac|^(talk) 03:44, 5 October 2005 (UTC)

Ginger

How is ginger harvested or processed?

Ginger is picked by hand; see [23] for a description of post-harvest processing. Gdr 21:24, 3 October 2005 (UTC)

Just a Thought/Gravity

I am a bit simple and find it hard to follow articals on physics when mathmatical formula are used. I understand that maths is the language of physics but as soon as the numbers come up it might as well be written in another language. Anyway I'm going to attempt to ask a question which I hope doesn't sound to stupid and I hope some one can answer it in a way that I can under stand.

The question is about the speed of gravity. I read that two heavenly bodies ie. earth and moon, are tied together by the pull of gravity and that if one of these bodies were to instantly vanish then the gravitional pull between them would also vanish instantly. This affect would be instant regardless of the distance between the two heavenly bodies. The argument also exists that nothing can travel faster than the speed of light. So there is a conflict between the two schools of thought.

My question is probably answered in some mathmatical jargon some where but.... if gravity existed as a sort of cloud around a heavenly body and another heavenly body in that cloud were to vanish what sort of affect would that have on the heavenly body that stayed behind? Or to look at it another way, if I pulled a pebble from the ocean would any of the other pebbles in the ocean notice?

The vanishing object would suffer a collapse of it's gravitional field and the remaining object would continue to exert the same degree of gravitional pull as it's own mass would allow. The only thing to change would be the interaction between the two.

The question then is is an interaction an actual physical thing in it's own right? I can interact with another person in a room with out any direct transfer of energy between me and the other person. A wink or jesture could transfer information either locally or across streets or fields and should the other person vanish my own condition would remain the same.

I'm not realy sure about the whole argument because in order for the moon to be released from the pull of the earths gravity the earth would have to vanish...which ain't going to happen...not in this universe.

I don't think this is realy a question but more like just a thought which I hope more learned people will comment onEye 22:14, 3 October 2005 (UTC)

Just a quick anser, the effects of the "vanishing" would not be felt instantly. I'll let someone else explain this bit better because I couldn't put it in a simple way. But see: gravity, graviton, gravitational wave. ☢ Kieff | Talk 23:03, 3 October 2005 (UTC)

According to Einstein's model of gravity, changes in the gravitational field propogate at the speed of light. In Newton's theory, changes propogated instantaneously. Newton knew this about his theory, and disliked it, as have most people since. Now that Newton's model is 400 years old, and we have a more accurate model, there really isn't any school of thought that says changes in gravitational field are instantaneous. -Lethe | Talk 00:08, 4 October 2005 (UTC)

Yes, changes in gravity propagate at the speed of light. However, it is meaningless to talk about a "body", eg. a star, vanishing. A body can move and its matter can turn into energy, but the gravitational mass will remain unchanged. I know of no process that can make (relativistic) mass vanish.

OK! So I'm 400 years out...I'll catch up...eventually?

Einstein's General Relativity saids that space-time continuun is simply a piece pf fabric, when there is a massive object in space-time, it will curve the fabric of space time, like a bowling on a piece of rubber sheet. The earth keeps its orbit because the sun curved the space nearby, forcing earth to follow "the trace" that the sun had curved. Light travels at 300000 m per second, and since only light can maintain the speed of light, gravitational waves cannot act instantaneously if the sun suddenly disappears. Since light takes 8.3 minutes to reach earth from the sun, the "vanish" of the sun will not act instantanesouly.

compander 'mu' law in digital quantizer

in digital quantization of a signal for a 'mu' =255 compander does the value 255 come from the sum of the number of representation levels that are available to represent the input or does it come from some other interpretation ??

--203.200.95.130 22:22, 3 October 2005 (UTC)

Visible cloud in front of a turbofan engine

File:Intake vapor.jpg

The cloud looks like this.

A similar cloud caused by a sonic boom.

I saw a lens-shaped cloud formed in front of a Boeing 777's cowling edge when the airplane was taking off in a foggy night. I don't know what caused it. So far my best guess would be the cloud was caused by the over-ingestion of air by the huge engine during the first several minutes (low pressure -> drop in temperature -> condensation). Am I right? -- Toytoy 23:21, 3 October 2005 (UTC)

Well, I'm not sure I can agree with your "over-ingestion" statement. But yes, I think if the air is speeding up in front of the intake, one would expect, due to Bernoulli's Principle a drop in both temperature and pressure, and if the air is already very close to the dewpoint, condensation causing a cloud. A similar effect causes condensation at the centre of wing-tip vortices (on which I can't believe we don't have an article! Though we do on wing tips and vortex). moink 08:35, 4 October 2005 (UTC)

Wingtip vortices has the article :) Yours is now a redirect. — Lomn | Talk / RfC 15:01, 4 October 2005 (UTC)

running windows xp pro on a network

I have six(6) computers,used for small internet business. i want to purchase a licensed MS Windows XP pro. My question is: Is it legal to install a single OS to the entire local area network? 203.87.201.246 00:06, 4 October 2005 (UTC)

No, it's not legal. Microsoft requires you to have either an individual license for each computer (volume licensing starts at 5 units, so you could check that out) or a site license. — Lomn | Talk / RfC 00:10, 4 October 2005 (UTC)

What's more, I believe XP will check if other machines on the LAN have the same serial number, and if it finds a duplicate refuse to work properly. -- Bob Mellish 00:18, 4 October 2005 (UTC)

Actually, XP doesn't check on serial numbers (large corporations use a single serial number for all installations), but it does check that the machine names and security Ids are unique on the network. This last is only an issue if you use disk cloning to set up your machines. If you install each machine separately, the network will have no problems, but Microsoft will start asking some hard questions when you try to register the copies.-gadfium 03:40, 4 October 2005 (UTC)

Bursting

How does bursting speeding up processing work?

have you checked Burst mode? or done some general searching on wiki first? Boneyard 09:24, 4 October 2005 (UTC)

WHAT MAKES THEM GOOD??? (TFT-LCD, CRT)

is it true that the cophixalus exiguus by passes the tadpole stage?

yes

Health effects of tea vs. coffee?

My grandfather, a retired doctor, used to tell me that tea was a lot less harmful to drink than coffee, because it contained theine as opposed to caffeine. He claimed that tea would keep you awake but not "jittery", and would let you down from the high gracefully, whereas coffe would cause you to "crash". The article on caffeine appears to refute all of this.

So, what's the deal? If I want a beverage that keeps me alert and gives me the drive to, well, edit Wikipedia instead of working, is there any advantage (or disadvantage) to drinking tea as opposed to coffee? --Ashenai (talk) 11:17, 4 October 2005 (UTC)

• Caffeine is known to keep you alert and coffee usually contains lots more of it than tea, so coffee or if you can afford it a equivalent volume of Espresso is sure to keep you up. Additionally sugar keeps your brain active. - 131.211.210.14 12:51, 4 October 2005 (UTC)
• Caffeinated drinks hit different folks differently, so I'd advise you to experiment, say a week at a time on coffee, black tea and green tea. My own experience is in line with your grandfather's advice, but lots of folks handle coffee much better than I do. One caveat: many coffee shops make crummy tea. You need to see the bag doused in water from a boiling kettle or, second best, the scalding tap from the espresso machine. If they hand you a cup of lukewarm water for you to drown the bag in later, that ain't tea. Oh, and our caffeine article says that theine is caffeine. Sharkford 14:09, 4 October 2005 (UTC)

Lost my USB ports

Hi, I have my internet connection shared from in a LAN setup at home and today when I went to try get on the net I couldn't. Well I investigated a bit and found out my svchost wasn't operating. I did a "repair" from the windows CD (i'm running XP btw) and that fixed the LAN up fine. But then I released I'd have to reinstall service pack to again to get back USB 2.0 (which was wierd because in the control panel the windows firewall was still visible). Anyway I reinstalled that but after it had completed and I had restarted I lost all my USB ports. Device manager says that this device is working correctly, however none of my USB devices are working (including my mouse). Obviously working without a mouse is a big pain so I dug out my little green convertor and stuck the mouse into the PS/2 port and tried that. Still nothing. Can some please help my get back my USB!! --Fir0002 11:25, 4 October 2005 (UTC)

Well, I don't know about your USB ports, but bear in mind that your mouse won't be detected on the PS/2 port unless you restart your computer. --David Wahler (talk) 13:03, 4 October 2005 (UTC)

Q about astronomy

When looking at the night sky, are all the stars that are visible with just the naked eye, from our own galaxy? Mortene 13:28, 4 October 2005 (UTC)

Yes and No. If you are in the Southern Hemisphere, you will be able to see the Large Magellanic Cloud and the Small Magellanic Cloud, which are separate galaxies. All over the world, you can see galaxies with the naked eye (if you are in a place with low enough light pollution) but you would probably think that they are single stars.... Physchim62 13:49, 4 October 2005 (UTC)

The Andromeda Galaxy is also visible to the naked eye, as are other members (those more closely related to the Magellanic Clouds) of the Local Group. I suspect the "yes and no" of the previous answer largely relates to the fact that while you can see extragalactic stars, you can't see individual extragalactic stars. However, the interesting case of Andromeda is that, around 120 years ago, a single extragalactic star (supernova S Andromedae) became naked-eye visible with a magnitude of 6. — Lomn | Talk / RfC 14:58, 4 October 2005 (UTC)

Thanks for the replies! Very interesting, and just the kind of response I was hoping for. Mortene 07:45, 5 October 2005 (UTC)

what is operating system

The system that allows a computer to operate. See Operating system. Proto t c 14:21, 4 October 2005 (UTC)

In simple terms, the interface between the hardware and the application software. Microsoft Windows is perhaps the most popular. You get the Personal Computer Hardware, the OS is installed on it, then various programs like e-mail and word processing is installed to run on the OS. AlMac|^(talk) 15:19, 8 October 2005 (UTC)

glaciers in the ice age.

I have always heard about the glaciers that covered the northern part of the continent during the ice age, and how they transported rock and debris south, or dug out the great lakes. Living in Michigan, I can see where they left moraines. However, I have never heard a good explanation as to the force that propelled these glaciers forward. There is no real elevation gain from Michigan to the North Pole. It's not like these gaciers were flowing downhill like they do in mountainous regions.

Glaciers move by the influence of pressure and gravity but not from the direction of the North Pole southward. They follow the local contours of the land they are on. Pile anything high enough and it will eventually move outward and downward. Glaciers care not for north or south (or anything else for that matter) but simply form and move based on local conditions and forces until they retreat, also because of local conditions. So, basically, in an ice age the local conditions become favorable for the formation of glaciers over a much larger area of the world. They did not move southward, they formed further and further south as the conditions "worsened". Qaz ^(talk) 17:59, 4 October 2005 (UTC)

If that were true, how do you explain glacial moraines, glacial erratics, rock scouring, etc. Clearly during the ice ages, glaciers both expanded and moved. Part of this can be attributed to elevation changes and some simply to the weight of the glacier causing it to spread at the edges. In some parts of North America, the land is still rising from weight of the glaciation that ended 10,000 years ago. Rmhermen 23:12, 4 October 2005 (UTC)

My point was not that glaciers did not move. My point was that when they did move it was not in a wholesale way from north to south. Glaciers do move and that movement causes many geologic features but glaciers move not away from the poles but based on local conditions. They are much like rivers; there is no preferred direction for rivers to flow except to lower elevations. In the ice ages the climate was much colder in North America so there were glaciers at what we consider very southern latitudes but they did not come down from the poles. They formed locally and moved just like mountain glaciers do, mostly downhill. The major difference between a valley/mountain glacier and a continental glacier is scale. All the same principles apply. Qaz ^(talk) 05:09, 5 October 2005 (UTC)

I suppose this talk about local glaciers forming is about mountainous areas. In the Netherlands we have a big pile of sand called the Veluwe that was formed because it at the edge of the icecap. And the Netherlands being (and always having been) flat, I suppose the movement was southward. Another thing I suppose is that all those lakes in the north of the Netherlands (and in Finland, which is also flat) were formed by the weight of the ice. DirkvdM 12:33, 6 October 2005 (UTC)

Are you sure that the area was not made flat because of glaciation? Qaz ^(talk) 17:30, 6 October 2005 (UTC)

Actually I looked into it and there are other reasons for the Netherlands being so flat but glaciation can tend to level an area which is why I was wondering in the first place. Qaz ^(talk) 04:15, 7 October 2005 (UTC)

Michigan was at the edge of the Laurentide ice sheet that created the Canadian Shield, so you need to read the ice sheet article which explains how such large masses of ice were able to move. The force that pushed the ice sheet was of course the enormous weight of the ice. Gdr 20:38, 6 October 2005 (UTC)

One thing that is difficult to visualize is that ice under pressure behaves like a fluid, not like a crystaline solid. That is, it flows like thick gelatin. You can create a small scale model by putting jello on a large plate. It will slowly spread out in all directions, especially if you keep adding more to the top to simulate snowfall. StuRat 06:58, 9 October 2005 (UTC)

Reaction of vinegar and bicarbonate of soda.

In the reaction of sodium bicarbonate with acetic acid, forming sodium acetate, water and carbon dioxide (NaHCO3 + C2H4O2 => CH3COONa + H2O + CO2), I read that the molar mass of acetic acid is 60.05 g/mol, and that of CO2 is 44.01 g/mol. Also, the formula weight of sodium bicarbonate is 84.0 amu and the molecular weight of sodium acetate is 82.0 amu.

I wish to derive a recipe for creating carbon dioxide. From the above information, how can I determine the relative quantities of vinegar and bicarbonate of soda to use so that all the powder C2H4O2 is dissolved by the liquid NaHCO3?

And how can I calculate the ammount of CO2 which would be generated? --- Snonskoid

What you need to do is examine reaction masses. One part NaHCO₃ and one part C₂H₄O₂ makes one part CO₂ (by mole, not by mass). You can disolve all the C₂H₄O₂ by using entirely too much NaHCO₃, but this is obviously inefficient. Instead, match molecular parts for the most efficient method. Then calculate the generated CO₂ by the same method. — Lomn | Talk / RfC 18:17, 4 October 2005 (UTC)

binary liquid explosives

what are binary liquid explosives and what are the chemical structures--195.93.21.103 16:36, 4 October 2005 (UTC)

As far as I'm aware binary explosives are those that are stored as two non-explosive chemicals which are then mixed just before detonatition to produce explosive. I don't know enough about them to chemical information. Robmods 17:47, 4 October 2005 (UTC)

• Any reaction with high gas production will cause the capsule to explode, because the gasses won't fit in it anymore at some point. Most of such reactions are exothermic as well. - Mgm|^(talk) 21:58, 4 October 2005 (UTC)

Mona Clonal Antibodies?

What are the potential moral implications of their use?? Is it really appropriate to use them? Taking one life to save another? how is this justified? and why is there no article on the subject monaclonal antibodies, mona clonal antibodies, even monaclonalantibodies are all redlinked, looks like someone is afraid to have this argument--WwJd 16:47, 4 October 2005 (UTC)

I believe you have misspelled monoclonal antibody. — Pekinensis 16:57, 4 October 2005 (UTC)

That doesn't change the ethical considerations? now does it?--WwJd 17:16, 4 October 2005 (UTC)

Well, it does invalidate your "too afraid to discuss this" comment. Also, I fail to see anything about taking lives in our article. Could you elaborate on your concerns? — Lomn | Talk / RfC 18:12, 4 October 2005 (UTC)

There is nothing unethical about monoclonal antibodies. They are not made from fetal tissue. They are most commonly generated in a laboratory. alteripse 21:39, 4 October 2005 (UTC)

• And that makes it alright? Growing unborn children from cloned tissue just so you can harvest their antibodies is hardly as 'harmless' as you make it sound, are they really any less human just because they've been cloned?--WwJd 22:12, 4 October 2005 (UTC)
  • Um, I think the point that Alteripse is making is that producing monoclonal antibodies does not require cloning fetal tissue. Are you sure you not confusing monoclonal antibodies with embryonic stem cells? -- Bob Mellish 22:23, 4 October 2005 (UTC)
    • If they made monoclonal antibodies from humans I suppose it might be unethical. Especially the final bleed. David D. (Talk) 22:36, 4 October 2005 (UTC)
    • I thought I gave a straight answer. Monoclonal antibodies are copies of human antibodies generated in laboratories and factories. Are you just here to pick a fight? alteripse 22:50, 4 October 2005 (UTC)
      • Looking at his contribs, quite possibly... Shimgray | talk | 00:13, 5 October 2005 (UTC)
        • Perhaps the editor needs to be directed to a discussion forum or a chat board or something. --jpgordon∇∆∇∆ 00:23, 5 October 2005 (UTC)

• I can see I'm outnumbered--WwJd 03:19, 5 October 2005 (UTC)

Make that outwitted. DirkvdM 12:38, 6 October 2005 (UTC)

Agreed. Your premise that a life is taken to save another is just plain wrong, no life, even the life of a fetus, needs to be taken to produce monoclonal antibodies. And as for the redlining of the links, that's only due to your atrocious spelling. StuRat 06:43, 9 October 2005 (UTC)

Asteroid Belt aroun Earth

I had read somewhere that the Voyager missions detected a very faint ring around earth. Is this true?

It wouldn't be Voyager (those missions are to Jupiter and beyond), and it wouldn't be anything like an asteroid belt. However, scientists do believe they have observed very faint dust clouds at Earth's L4 and L5 (Trojan) Lagrange points (with respect to the Moon), akin to the collection of space debris at Jupiter's Trojan asteroids on a much smaller scale. They're known as Kordylewski clouds. If Earth had a natural ring, it would orbit around 20,000 miles up (inside the Earth's Roche limit) and would be easily observed. Check out Asimov on Astronomy (it should be available via your local library) for more on this. — Lomn | Talk / RfC 18:08, 4 October 2005 (UTC)

my dream

can i get addmission latest by jan2006.?

Please re-state your question. Admission to what? — Lomn | Talk / RfC 18:11, 4 October 2005 (UTC)

Death

I am doing a research paper on death and its connection to a possible aferlife.My question is: Who is the author of the article titled Death, and who are their sources? I am quoting the article because i found it interesting and need the information for my bibliography. One last thing, has anyone ever been able to prove the existance of alternate dimensions or an afterlife, solid evidence? If anyone could help me i'd appreciate it.(make sure you won't mind if i quote you in my research paper) This paper determines my semester grade (i'm a high school senior) so i'd appreciate any info such as credible sources about death or the afterlife, from any viewpoint (medical,spiritual,theoretical, religious, ect...) thank you

For the first question, see Wikipedia:Citing Wikipedia. Frencheigh 18:40, 4 October 2005 (UTC)

That is not a scientific or mathematical question! From Christian point of view, Afterlife would be( if you were a Christian) to go to Heaven and be with god for eternity, not hell.

--Jake Haines 18:42, 4 October 2005 (UTC)

For the second, no conclusive evidence has ever been found either way, and there is no likelihood of such evidence being found in the forseeable future. (Connie Willis' novel Passage is about a researcher studying near-death experiences, and has a few trenchant comments about the problems of working in this field; it's not one where productive research is easy) Shimgray | talk | 18:44, 4 October 2005 (UTC)

If life after death were proven beyond doubt you'd probably notice that by the fact that we stop calling it 'death' :) . DirkvdM 12:45, 6 October 2005 (UTC)

Evolution VS Intelligent Design

Is there links and/or information regarding which might be more valid AKA research?

--24.1.191.232 19:35, 4 October 2005 (UTC)

You might look at our article on evolution or evidence for evolution, both of which have links relating to this. In short form, mainstream biologists say they have far more reason to support naturalistic evolution than intelligent design, that all of the supposed ID evidence falls short, and furthermore would say that ID doesn't have any research program associated with it. ID supporters would claim that mainstream scientists have ruthlessly suppressed the truth of their work and are ideologically and methodologically opposed to their approach. Repeat many times over and that's pretty much the evolution v. ID debate in a nutshell. --Fastfission 20:03, 4 October 2005 (UTC)

Also, the mainstream would argue that ID is deeply philosophically flawed in that it does not follow established methods of science such as falsifiability, that there isn't any positive evidence for ID in existence, and that as a subject ID cannot be researched because key parts, like intelligence, design and complexity are left intentionally undefined.--Fangz 22:00, 4 October 2005 (UTC)

Mainstream 'science' argues a lot of things--WwJd 22:10, 4 October 2005 (UTC)

Mainstream scientists continually argue with each other. That's how it moves forward, modifying old models or replacing them with new models to fit the observations. In fact, to make your name in science the best thing to do is discover something so new and different that it brings into doubt previous dogma. RNA interference is a recent example. It seems that the ID 'scientists' are on the cusp of big news, i can't wait to here their discoveries. David D. (Talk) 23:29, 4 October 2005 (UTC)

birth rate

what is the birth rate in massachusetts?

If you do a Google search for "birth rate massachusetts", the first page that comes up is this press release from the state (sorry, Commonwealth...) government, discussing a report containing this information from 2003, and much, much more. This report, all eight chapters of it, is available here, as well as historical data from earlier such reports. Google (and the other search engines) are your friends...--Robert Merkel 00:44, 5 October 2005 (UTC)

particles are always in what

Please clarify your question. What, exactly, do you want to know? --Ashenai (talk) 22:30, 4 October 2005 (UTC)

Maybe it's a riddle...? -- SCZenz 00:47, 5 October 2005 (UTC)

constant motion?--Michael 04:28, 9 October 2005 (UTC)

a matrix of some sort? --66.82.9.62 04:12, 18 October 2005 (UTC)

Heroin in Food

I know this sounds crazy, but I NEED to know EVERYTHING that happens to the human body if you EAT heroin. I have even gone on sites in New Zealand and Australia trying to find the answer to this. I have found nothing anywhere! I want to know how it breaks down chemically, the amounts in blood versus stomach contents, morphine to 6MAM, how long it takes to die. I think you get it.Thank you for ANY answers you can give me. Toni I'm sorry!I did not mean to send this twice.Until my daughter died I,I wasn't even sure how to turn one on.

What exactly do you mean by the phrase "how long it takes to die?" That would probably mean disintegrate or dissolve or dissociate or discharge from the body when referring to heroin.--Screwball23 14:41, 17 October 2005 (UTC)

Search medline for heroin overdose like this [24]. You get hundreds of hits. You will have to sift for those that might describe oral overdose, like this PMID 10829332. Look at its bibliography for previously published articles on oral overdose. What you really want is something that describes the characteristic effects of oral OD vs injected OD because the latter is hundreds of times more common. Alternatively, go to a medical school library and ask for some toxicology and drug abuse texts. Look at the references to their chapters. I assume you are not dealing with an oral OD at this minute? If so, get him to the ER. alteripse 23:41, 4 October 2005 (UTC)

One warning – medical journals are written for doctors and scientists to communicate with each other, and consequently they assume a *lot* of background knowledge that doctors or biological scientists receive as part of their college training. It may take you some time and a fair bit of reading to familiarise yourself with the relevant background (though the Wikipedia is a reasonably good place to get a lot of that background), but it's by no means impossible. Many articles will also use some statistics, so you may need to learn a bit about that. Good luck, and I hope you find what you are looking for, whatever that is. --Robert Merkel 01:01, 5 October 2005 (UTC)

If you eat heroin, it will be absorbed either as heroin itself or as morphine (some heroin breaks down to morphine in the stomach). What happens depends on the dose and the individual. The opiates will be absorbed slower than if the were injected, but the total length of time that the patient is exposed will be longer. Physchim62 15:29, 7 October 2005 (UTC)

Would inducing vomiting be a good idea? --03:21, 13 October 2005 (UTC)

Itunes Problem

I have a bit of an interesting situation regarding iTunes. I am attempting to share my music so that a friend can access it. However, we seem to be on different subnets, despite the fact that we are using the same ethernet jack to access the internet. Would it make a difference that I intially installed and started intunes using a different ethernet jack across campus? The initial network setup was also done across campus, perhaps if I change my subnet this will solve the problem? Thanks for any suggestions!

How exactly are you using the "same" ethernet jack to access the internet? iTunes isn't designed to work via the internet anyway; rather, it's designed to work over local networks, so if you are both using the same router or something like that, things should be hunky-dory. Also, what are the models and capabilities of the computers you are using? Are they AirPort/802.11 capable? Garrett Albright 17:08, 5 October 2005 (UTC)

Poliosis / White Forelock

Hi This is not really a question but more of a request. I have performed some google searches to find a name for my husband's white tuft of hair above his forehead. I found Poliosis and White Forelock. I also found a list of dreadful diseases of which I'm fairly certain he has none. I then tried to find any information possible on Wikipedia and the search came up with zero. I'm just wondering if there are any personality traits (like extreme intelligence or other endowment) that might accompany this somewhat less common physical characteristic. I'd love it if anyone in-the-know could add this subject to your website.

thanks

There are many minor genetic physical traits that can occur by themselves or with several other physical anomalies. When they occur by themselves they have no hidden significance and cause no problems. When they occur with multiple other anomalies, some of those other problems can turn out to cause serious trouble. This combination of anomalies is usually referred to as a congenital syndrome. Other examples of minor physical anomalies that can be of no significance by themselves or can occur as part of a more serious syndrome are little pits in front of the ears, short broad thumbs or fingers, high-arched palate, and indented chest. Finally, there are no personality traits associated with this type of minor isolated anomaly because the only body part affected is that area of the scalp. alteripse 01:44, 5 October 2005 (UTC)

You can get a tuft of white hair by being scared shitless. Someone in my family once got that after she had fallen between railway tracks and had a train run over her. She was otherwise unharmed, but you can imagine her state of mind at the moment. But now I wonder how such a thing can happen. Does all the pigment get sucked out of the hair? And how does a scare cause that? DirkvdM 12:53, 6 October 2005 (UTC)

Having the pigment "sucked out" of hairs is as likely as having a sudden fright turn your nail polish from red to blue. Hairs already extruded from the hair follicles do not change color unless dyed, bleached, or oxidized. alteripse 03:16, 7 October 2005 (UTC)

I agree that the color of existing hair won't change due to stress, but having a localized loss of pigment in future hair due to a stressful episode isn't impossible. I don't know if any studies have been done on this, but I can easily imagine that stress hormones like adrenalin could interact with pigment cells and cause them to shut down. Other causes could be genetic or environmental, such as Sun-bleaching (which actually could destroy the pigment in existing hair). StuRat 06:32, 9 October 2005 (UTC)

math

If you know the exact date a person was born (year, month, and day) how can you quickly tell them what day of the week their birthday will fall on this year? With no help from a calender thanks.

See Calculating the day of the week.-gadfium 03:47, 5 October 2005 (UTC)

ABOUT BULLSEYE NETWORK VIRUS

When I use Internet Explorer, suddenly, a pop-up opens with the heading 'BULLSEYE NETWORK'. This pop-up appears when I open any website! Is that a virus that has attacked my computer or my Internet explorer? What should I do to get rid of that? Can anyone tell me more about this Virus?

You have aquired a piece of adware. This is not technically a virus, but is almost certainly software you don't want on your computer. It is designed to be difficult to remove. I recommend you get a copy of Ad-Aware or any of its competitors and run it on your computer. The following Symantec page may be useful to you: [25].

To prevent such infections in the future, please consider using a different browser, either Firefox or Opera. Internet Explorer is particularly prone to such infections.-gadfium 03:42, 5 October 2005 (UTC)

Or better still, switch to Linux. That should shield you a whole lot more against viruses and the like. DirkvdM 12:55, 6 October 2005 (UTC)

Linux Lover 69.181.206.232 04:21, 10 October 2005 (UTC)

Well, nothing wrong with that, is there? DirkvdM 18:16, 11 October 2005 (UTC)

If you switch to Linux, then there are still companies openly trying to abuse your computer for malicious reasons and not facing any consequences for it (even if it doesn't affect linux users much), so I suppose you could say it hasn't solved the problem. (and might even still be a problem if they find a vulnerability in some Free Software, or trick a linux user into installing their software). I'd take 69.181.206.232's comment as a compliment though... Ojw 18:35, 14 October 2005 (UTC)

maths

Try starting in Mathematics --Borbrav 04:05, 5 October 2005 (UTC)

Random vector member?

In the standard template library for C++, is there any trivial way to get a random member of a vector (or map) safely? - RedWordSmith 04:57, 5 October 2005 (UTC)

If I remember correctly (and I may not), isn't access to a random member of a vector O(1)? I believe vectors aren't linked list-backed types. Or is what you ask in the "safely" part? If so, what do you mean? Dysprosia 09:07, 5 October 2005 (UTC)

User:RedWordSmith wants to choose a random element and to access it with a single command. I don't think that is possible. Masatran 10:37, 5 October 2005 (UTC)

Yes, exactly. Any ideas on what the best way to do this using multiple commands? I've thought about shuffling the entire vector somehow a couple times and then taking an element from the top, but that can't be efficent no matter how it's done. - RedWordSmith 20:57, 5 October 2005 (UTC)

C++ vectors are random access, implying O(1) access, thus these are most likely not linked-list like types. What is wrong with using operator[] on the vector? Dysprosia 22:47, 5 October 2005 (UTC)

Maybe I'm missing something here, but wouldn't the following three step process work:

1. Find out the number of elements $l$ in the vector (my C++ is very rusty, but isn't that the length method of the vector class)?
2. Generate a random number $i,0\leq i<l$ with a pseudo-random number generator.
3. Access the i'th object in the vector (either with operator[] or the at method, which is range-checked.

The choice of which pseudorandom number generator to use depends on your application. If, for some reason, it is important that an attacker not be able to predict which element will be selected next based on the elements selected previously, you need a cryptographically secure pseudo-random number generator, otherwise any modern generator, including the one in your system library, will probably do (though I prefer to use the Mersenne twister for all my own simulation work because it's both good and fast).

If you want a guarantee that you won't get repeated elements, then a shuffle is probably the best way to go. But here's a basic performance tip; if your objects are large, create a vector/array of pointers to them and shuffle the pointer array rather than the objects themselves.

As to the interface, surely you could define a subclass of vector which adds a "ranelement" method that implements the procedure I've described above? --Robert Merkel 01:00, 6 October 2005 (UTC)

OH. I get it now. Red wants to access an element at random. Yes, that solution is the one that first comes to mind. I don't think there's a simpler method... Dysprosia 09:31, 6 October 2005 (UTC)

Thanks, I'll give it a try. For some reason I was under the impression that the element choosen by the random number generator might not exist; I guess I'm just too used to plain C. I think I also got thrown off track reading about nonstandard methods to get random samples at one point. - RedWordSmith 00:06, 7 October 2005 (UTC)

Mod it with l if your RNG doesn't do generation within a certain range. Dysprosia 10:27, 7 October 2005 (UTC)

Anabolism and lifespan

Does a moderate level of body building and the associated muscle mass gain cause a decrease in life span? Lets assume that the person doing the body building and undergoing anabolism has a normal BMI and average build (that is, they are not overweight or underweight). Also assume that there are no steroids or supplements involved – only a small increase in protein rich foods being consumed. 205.188.117.71 04:59, 5 October 2005 (UTC)

No evidence is available for your specific question because such changes are never done in isolation from other factors that might change lifespan: healthier eating (e.g., reduced fat intake), reduction of unhealthy exposures (e.g., less time with secondhand smoke), etc. There is some evidence that in small mammals those who are allowed to eat less calories daily over most of their lifespan live a bit longer; this appears to be a phenomenon distinct from simple avoidance of obesity but we have no way to extrapolate this to people or to know exactly what the mechanism is. This topic of changing life span by changing daily living habits or eating habits is generally referred to as life extension and much has been published online and in the scientific literature but the quality ranges widely and much of what has been written about people is speculation, opinion, or marketing written to sell a product. Be skeptical. alteripse 10:36, 5 October 2005 (UTC)

The trick to a long life is to metabolize slowly. Like my turtle which I expect to out live me by about 100 years. I metabolize quickly because I like to have fun...unlike my turtle who just sits in the sun all day.--Eye 20:13, 5 October 2005 (UTC)

• Our Caloric restriction article is worth looking at as well. Capitalistroadster 04:55, 7 October 2005 (UTC)

Graying Hair

Why does hair turn gray or white as humans age?

• Our Hair article states: "Older people tend to develop gray hair (actually colorless) because the pigmentation in the hair gets lost and the hair becomes colorless. The age at which this occurs varies from person to person, but in general nearly everyone 75 years or older has gray hair, and in general men tend to become gray at younger ages than women." Capitalistroadster 07:19, 5 October 2005 (UTC)
  • This answer is perilously close to Moliere's explanation that a sleeping potion worked "because of its dormitive properties." I am not sure how clearly we understand the process by which hair follicles stop having pigment. Is pigment generated by intracellular processes that are programmed to stop at a certain age? Are there separate cells at the base of hair follicles that add the pigment to a growing hair? What is the difference between hair follicle cells that grow a pigmented hair versus a non-pigmented hair? Are these hormone-dependent changes like puberty or menopause-- if so we have surprisingly little understanding of this type of change in early or middle adult life. Are these specific genetic responses to a certain duration and level of hormone exposure, like male pattern baldness? Interesting question. Anyone want to research an article on hair color? alteripse 10:52, 5 October 2005 (UTC) Well, guess what, the answer was already in our article:

The change in hair color is caused by the gradual decrease of pigmentation that occurs when melanin ceases to be produced in the hair root, and new hairs grow in without pigment. Two genes appear to be responsible for the process of greying, Bcl2 and Mitf. The stem cells at the base of hair follicles are responsible for producing melanocytes, the cells that produce and store pigment in hair and skin. The death of the melanocyte stem cells cause hair to begin going grey. (Nishimura, et al., 2005)

Perhaps you didn't mean to get into the technical details of how pigmentation stops being produced, but were rather asking why, what evolutionary purpose does gray and white hair serve ? It may be that it serves no purpose, and is just a malfunction that isn't very harmful, so isn't selected very strongly againt. Another possibility is that visual age markers, like gray hair and wrinkles, are in some way helpful to the species. On the positive side, they may be ways to identify older people, who presumably have valuable knowledge and experience to offer, which may help the group survive. A more negative interpretation may be that this helps to identify people who are beyond their ideal fertility age, and thus should be avoided for younger more fertile mates. If either of these is a benefit to marking older people with gray and white hair, then evolution may actually select for this feature. Note that many other mammals share this trait with humans. StuRat 06:20, 9 October 2005 (UTC)

thrust agumentation

why a water nozzle is having a greater reaction when it is faced by a rigid wall very close to it rather than when it is faced in free air. --202.137.218.75 07:51, 5 October 2005 (UTC)Abhishek gupta, India
(formatted question and removed email – Mgm|^(talk) 09:52, 5 October 2005 (UTC))

Newton's third law? Dysprosia 10:30, 5 October 2005 (UTC)

You didn't say if the wall was right up against it or just close. When the nozzle is pressed right up against the wall the water can't get out as easily and allows the pressure to build up. This is also why a nozzle causes greater reaction, than when water comes straight out the end of the hose.

Dysprosia is correct. When in the open air, the water pushes air out of the way, as the air can freely compress and move. As you approach the wall (which presumably does not compress or move), the water exerts a force on the wall, and the wall effects a reciprocal force on the water. At distance, the water tends to splatter into the air (per the initial condition). As the nozzle gets closer, more of the wall→water force is directed back toward the hose. Since water isn't compressible, this force transmits into the hose collectively. When the nozzle is directly adjacent to the wall, virtually all of the force affects the hose. — Lomn | Talk / RfC 14:36, 5 October 2005 (UTC)

Stabilizing the frequency of vibrations in a quartz crystal used in an oscillator circuit

Dear Wikipedia Volunteer, I am currently undertaking a research project. For this to be successful, it is important for me to know how to stabilize the frequency of vibrations of the quartz crystal used in an oscillator circuit. The quartz crystal in question is a 14.3183 MHz oscillator, but the output frequency is accurate only till 14.31 MHz (i.e. about 10 kHz). How can I stabilize the vibrations so as to get accurate output frequency in the order of tens of Hz? I would be highly obliged if you kindly post the answer to my query at your earliest convenience, or give me a few references in this regard. Thanking you, Yours sincerely, Saikat Das (removed e-mail address)

Saikat, I don't know the details of your project, but if the crucial thing is that you need a high-precision clock signal, would something like these do the job? I found this by googling "precision oscillator"; lots of other relevant links turned up. --Robert Merkel 15:18, 5 October 2005 (UTC)

OpenDocument XML editor wanted

Is there any OpenDocument editor that can edit the XML elements directly? —Masatran 11:10, 5 October 2005 (UTC)

If I'm not mistaken you can do that with any simple editor. At least that's the way to do it with html. Or do I misunderstand your question? DirkvdM 13:01, 6 October 2005 (UTC)

List of text editors and XML#XML Editors. The problem is, that I don't think OpenOffice, KWord, etc. like to edit OGW as a set of textfiles, they prefer to interpret it. Ojw 13:41, 9 October 2005 (UTC)

Dance Pads Sales

Hello dear friends, Does anybody know how many dance pads (in units) are sold annually in the USA by manufacturer? Thank you Sincerely

Are you referring to Dance Dance Revolution pads? -Haon 00:02, 11 October 2005 (UTC)

Individual Generators and natural disasters

how long do individual generators last? Can generators communications be affected in natural disasters? should we be investing in new research to develop cheaper and better generators? Is the Department of Homeland Security in the US preparing for wide scale, long term power outages?

• Generators are more fuel-dependant than breakdown-prone, though such breakdowns can occur. On the whole, it depends entirely on the stockpiled fuel supply.
• I have no idea what generator communications are. Could you elaborate?
• Probably not. Again, fuel source is the main concern (and I'd consider a cold fusion generator more a problem of cold fusion research than generator research)
• I don't think there's any way the U.S. at large can prepare for wide scale long term loss of power. Check out some apocalyptic fiction (Alas, Babylon and Lucifer's Hammer are good examples) for thoughts on what such widespread devastation would mean for modern first-world society. In a nutshell, if a disaster of such magnitude strikes, basic survival will be far more important than maintaining the power grid. That said, reducing the dependancy on imported oil would alleviate a major choke point for the fuel supply. Nuclear energy (the most modular major power source) has been overwhelmingly unpopular since Three Mile Island and Chernobyl, however. — Lomn | Talk / RfC 14:27, 5 October 2005 (UTC)

Generators will last as long as there is fuel for them and they stay in good working order. I presume you mean emergency type generators like you might find in the hardware store. There is ongoing research to find new ways to produce power (like fusion or solar power) but my opinion is the generators we have are just about as good as they can be expected to get without a technological advance.

As far as your question about whether "Homeland Security" is prepared for anything except re-electing republicans, I think we got a pretty clear answer last month. alteripse 15:08, 5 October 2005 (UTC)

To quote someone or other – "There is a major disjoint between people who think national security means keeping the nation safe, and those who think it means blowing shit up." Shimgray | talk | 20:04, 5 October 2005 (UTC)

Photosynthesis

Give an example of an experiment to find if photosynthesis has taken place inside a leaf.

Please answer this question now beacause I have a test and I could not understand this question. Thank you

You could read photosynthesis, but we're not really in the business of doing other peoples' homework here. -- SCZenz 16:13, 5 October 2005 (UTC)

I'm feeling nice, so I'll give you a hint.... What is a product of photosynthesis that you can test for? -(Fang)

You mean like electrons? David D. (Talk) 22:23, 5 October 2005 (UTC)

Electrons are not a product of photosynthesis. Imagine photosynthesis as an equation. What does photosynthesis produce? --Fastfission 17:00, 6 October 2005 (UTC)

2H20 + light (4 photons) --> O2 + 4H+ + 4e- is the first step of photosynthesis. Also known as the light reactions. I was trying to give a clue, although I admit it was somewhat cryptic. The traditional equation for photosynthesis ( 6CO2 + 6H20 + light --> 3O2 + glucose) is very misleading since it does not recognise that there are several independent reaction associated with carbon fixation. The first step does not involve the fixation of carbon it is all about converting light energy into chemical energy. The reduction of NADP to NADPH using the reducing potential of the electrons. As well as ATP from the movment of the electrons through the electron transport chain in the thylakoid membrane. David D. (Talk) 17:25, 6 October 2005 (UTC)

Heroin

What happened to my ? on heroin when eaten in food? Thanks, Toni

We answered it. Read more closely above. alteripse 15:06, 5 October 2005 (UTC)

Internet Statistics

I am attempting to find some internet statistics:

1. How many people currently use Windows 98 vs. Windows XP?
2. How many people have dial-up vs. broadband?
3. How many people have an 800 X 600 monitor vs. 1024 X 768 or larger?

Thanks,
<removed e-mail address>

• I'm not sure about the numbers, but if you want to know this because of some design job, I recommend you design with the Windows 98 dial-up 800x600 users in mind (at the very keast offer a low-bandwidth option for them). There's nothing more annoying than site, images or programs that are not designed for your system. - Mgm|^(talk) 20:57, 5 October 2005 (UTC)

w3 publishes this info here: http://www.w3schools.com/browsers/browsers_stats.asp Boneyard 12:31, 11 October 2005 (UTC)

different question

If you buy stock in companies that sell this stuff, then you get their annual reports which have actual numbers of how many got sold that year. Some companies make their annual reports available to non-shareholders. So then you need to get them for every year since the products that interest you came out.

There are also places that have already done this kind of research and published the results, Gartner Research for example ... use Google or some other search engine (there are scores if not hundreds to choose from) to find places that do Research, then search them for the kind of research reports you interested in ... I think Gartner Magic Squares would be very close to what you looking for.

Gartner Magic Squares are charts of various types of products within some industry ... one dimension is all the stuff the products can do, another dimension is degree of market share the market leaders have, yet another thing shown is how good the stuff is relative to each other, with various vendors products plotted on this thing, accompanied by an article that goes into details about what is plotted on the graph.

AlMac|^(talk) 15:27, 8 October 2005 (UTC)

How do plants and trees live in islands where their roots are in sea water?

Hello everybody,

I have always been wondering while seeing some nature tv programs or photos or etc that how come trees are able to live in such conditions as in islands where the soil is ssandy and permeable to sea water and these trees most probably have roots that are soaked in salty sea water. Apart from the fact that many trees, as far as I know, could not stand the salt in the sea water, their roots are also not able to breath oxygen, could they? As you see in many commersial photos or educational tv products there are islands where their jungles are only a few meters away from the sea water. How is that?

So please let me know how do these plants survive? Is their roots in sea water at all? It those are those roots adapted to these situations or their is some mgical thing happening there?

I hope i could have been able to explain my question as good as possible.

Thank you for your replies in advance.

Eqbal Vakilzadeh

Plants, like other forms of life, are adapted to fit certian circumstances. Not all trees are the same.

It is not just about adaptations. Obviously mangroves do live in brackish water. They have several adaptations to allow this. High quantities of salt in their cells that means water can move from the brackish water to the even saltier mangrove cells by osmosis. This would not be possible for regular trees as you suggest above. mangroves also have air tubes in their roots specifically to get the oxygen down to the tissues under water. You're right that hypoxia this is a very real problem for trees that live in standing water.

With respect to the islands, the key is that the ground water can push out the sea water. This web site has a diagram and description [26]. Even trees at the edge of the island it is possible for them to get fresh water. David D. (Talk) 21:41, 5 October 2005 (UTC)

This is it. thanks for the info and the link. eqbal

Computing

differences between windows nt and windows 98

Apart from the fact that they're both versions of Windows from Microsoft, nearly everything. The code bases and design rationales are entirely different, and that filters through the whole of both operating systems. Check out Windows NT and Windows 98 for more. — Lomn | Talk / RfC 18:04, 5 October 2005 (UTC)

manufacture of dimensions in nanometer range

How is the stylus tip made up of hard material like diamond which is used in surface roughness measurements manufactured to have a radius in the range of nanometers ?What is the procedure involved?

                --------------------------------------------------------------------

Aggregated diamond nanorods have been made by a new method and there are more conventional methods such as Chemical vapor deposition. --JWSchmidt 03:22, 8 October 2005 (UTC)

Unknown Energy?

Would it be right to say that energy in its pure form is unknown to us? For instance I cannot see the light that passes across my field of view. It seems that we can touch, hear, and see energy but only when it is interacting with the matter of our own bodies, our eyes, hears, or skin and in doing so does the energy that triggers the reaction of our senses changes it form? If so would it not also be so that what ever device we construct to measure energy would have the effect of changing the energy which we try to measure? Could or does energy exist in a form unknown out side the world of matter that we exist in? --Eye 19:57, 5 October 2005 (UTC)

Energy is a conserved quantity that is associated with location (potential energy), motion (kinetic energy), and with matter itself (see E=mc²). Possibly the best candidate for "pure energy" would be the photon, the massless light particle, and you are absolutely right that one only sees photons when they interact with the matter in your eyes (or, if they hit your skin, they can give you a sunburn). It is a principle of quantum mechanics that you cannot observe anything without changing it; this applies to energy in any form, regardless of the device you build. To answer your last question, dark matter and dark energy are two things whose affects we can observe in cosmology but whose nature remains unknown to us; they compose the vast majority of the energy of the universe. Hope that helps! -- SCZenz 20:09, 5 October 2005 (UTC)

Mmm...I like the dark energy bit.--Eye 22:06, 5 October 2005 (UTC)

Better known as the Measurement problem. - Cobra Ky (talk, contribs) 22:15, 5 October 2005 (UTC)

Anything that exists outside the reality we live in can not be observed by us and therefore does not exist as far as we can (ever) tell. Dark matter and energy are theoretical solutions to problems in cosmology. One could say that they are observed indirectly, but then everything is observed indirectly. When I look at a table I really just register the light that is reflected by it. And I don't even see the light, but only register the effect it has in my eyes and brains. DirkvdM 13:54, 6 October 2005 (UTC)

1. Would it be right to say that energy in its pure form is unknown to us? No, that is not right. Energy is very well understood in physics.
2. For instance I cannot see the light that passes across my field of view. You see light that interacts with your eyes. You don't see light that is not interacting with you. Same for sounds, pressure (touch) and so forth.
3. [D]oes the energy that triggers the reaction of our senses change its form? Yes.
4. If so would it not also be so that what ever device we construct to measure energy would have the effect of changing the energy which we try to measure? Yes.
5. Could or does energy exist in a form unknown out side the world of matter that we exist in? No. Matter is energy. Energy is matter. Forms change. WAS 4.250 21:33, 10 October 2005 (UTC)

water solubiliry in the body with homeostasis

How is water solubility used to maintain homeostasis in the body? What are four examples of this?

It all depends on what points your lecturer made. Was there reding material set with this problem. it might be worth checking that first.David D. (Talk) 22:41, 5 October 2005 (UTC)

Freshwater Invertebrates and Marine Invertebrates

I am trying to find the basic information on what differentiates certain freshwater invertebrates with marine invertebrates. For example, there are several invertebrates (Crayfish, Jellyfish, snails, etc.) that live in either freshwater or marine/sea water, what differentiates them? Why can one species of crayfish live only in freshwater and not in saltwater? How is the freshwater crayfish different from the marine crayfish?

If anyone can help me to answer this, I would REALLY appreciate it! Thanks!

• Our Crayfish article states that in New Zealand "the name crayfish or cray, refers to a spiny lobster, and crayfish are called freshwater crays or koura, the Maori name for the animal." Is that what you are referring to?

Alternatively, I suspect that the Speciation article referring to the emergence of new species through Evolution and Natural Selection. Capitalistroadster 01:17, 6 October 2005 (UTC)

The basic difference is physiological. The freshwater organisms are better at pumping excess water out of their bodies, thus maintaining the salinity of their cells, coelomic fluid or blood. WormRunner | Talk 02:57, 6 October 2005 (UTC)

DNA/Cloning

How much of a DNA sample is enough to make a clone of something? What is the best source of DNA in relation to cloning?

No one has successfully made a cloned animal with just a DNA sample to start with. alteripse 00:56, 6 October 2005 (UTC)

To make an actual clone of something, you'd need to replicate all of its DNA (or extract a full set). A full set of the DNA of any living thing is present in every one of its cells. You could also read Genetics, DNA, and Cloning --Borbrav 01:20, 6 October 2005 (UTC)

In addition to the DNA you need the right environment, starting with the right cell (although I believe you don't necessarily need a cell of that specific species – something closely related would do). And then that cell needs a womb (natural or artificial) to grow in. DirkvdM 13:58, 6 October 2005 (UTC)

And you might want to try the article on Polymerase chain reaction to answer your "amount" question. --Michael 04:03, 10 October 2005 (UTC)

Cloning is typically done with an easily obtained cell, like a skin cell, or in the case of Dolly, this first cloned sheep, an udder cell. Cloning usually takes hundreds of tries, using one cell per try.

Computer languages

what is an atom in some computer languages?

Take a look at Lisp atom, and also Prolog. There may be other meanings of the term in other programming languages.-gadfium 02:54, 6 October 2005 (UTC)

Killing Me Softfruit : Which food would kill you first?

Of all the things a person in a modern Western democracy might normally consume as part of a meal, which would kill with the lowest dosage? The test subject is to be fed on the test food alone and is allowed any quantity of water and time for comfort breaks. --bodnotbod 01:46, 6 October 2005 (UTC)

My guess would be alcohol. — Laura Scudder | Talk 01:54, 6 October 2005 (UTC)

Oooh, fun game. Tricky though. For instance if you include trace amounts of things that we ingest but don't intend to and are not conscious of, the answer would be aflatoxins, other natural neurotoxins like botulinum toxin, or pesticides and other chemical contaminants. We certainly "might normally consume as part of a meal" trace amounts of these things, but it would take only mg amounts to kill us.

Now if you restrict your contest to things that we deliberately and knowingly ingest as food, then alcohol seems a pretty good choice if taken as a single dose (1-3 oz of pure ethanol can be fatal to an adult), but if spaced out it would require a much larger amount. Same for caffeine. However, your allowance for "any quantity of ... time for comfort breaks" would suggest we could stretch out the exposure. So it looks like you'd better impose more rules. alteripse 03:08, 6 October 2005 (UTC)

• I wonder if you could kill yourself by OD'ing on salt? --jpgordon∇∆∇∆ 03:59, 6 October 2005 (UTC)

Of course. You can OD on water or oxygen also. The amount of salt that would kill you if you had access to sufficient water and could take "comfort breaks" to unload some of it would be larger than the mg of caffeine that would be fatal. However it is not a bad suggestion if the contest limited you to a single dose you had to ingest in one sitting. alteripse 04:07, 6 October 2005 (UTC)

Well, a relatively small bite of most anything that can be lodged in the throat has taken down multitudes over the ages but I think I am cheating. Qaz ^(talk) 04:14, 6 October 2005 (UTC)

If you knew you had a food allergy- you could do it will a minimal amount of the relavant food stuff.--nixie 04:19, 6 October 2005 (UTC)

Vinegar wouldn't do you too much good either under the test conditions. Salt would fairly quickly cause renal failure (or drowning, by the amount of water consumed – this has happened in France). Cooking oil might start dehydration by diarrhea, but probably wouldn't work as fast as the others. Anything infected with cholera would be pretty fatal, as would certain uncooked beans, but that must certainly be cheating! Physchim62 15:41, 7 October 2005 (UTC)

Most of these seem rather unappetising. Except maybe the alcohol. How about a couple of pounds of green potatoes, nicely cooked in the means of your choice? Notinasnaid 17:41, 7 October 2005 (UTC)

That's almost cheating, too, as you wouldn't normally eat it. Along similar lines I could propose what killed Christopher McCandless: potato seeds which he helpfully discovered become poisonous in August. But so far I think alcohol is the best bet so far as things you'd normally ingest and could get someone to down fast enough. — Laura Scudder | Talk 17:55, 7 October 2005 (UTC)

Could you add some detail about how Christopher McCandless died to that article? Superm401 | Talk 22:18, 15 October 2005 (UTC)

A freshman died from water intoxication recently during a hazing incident at California State University, Chico. User:Zoe|^(talk) 07:45, 9 October 2005 (UTC)

• Some interesting answers, but I was tending to think of food rather than drink, so alcohol would have been ruled out. I'd like an answer that doesn't involve taking out one of the ingredients / chemicals of a food and eating that in isolation unless you would normally eat it in isolation too. --bodnotbod 00:27, 13 October 2005 (UTC)

Are you planning to poison somebody?--Shanedidona 03:15, 13 October 2005 (UTC)

• • Er...no. No. What an idea! Ha ha, er... (Hides extremely large punnet of strawberries under desk). --bodnotbod 20:51, 17 October 2005 (UTC)

Neurotransmitter Receptor Unbinding

When neurotransmitters are released, they bind onto a receptor on the post-synaptic neuron, and open a ligand-gated channel. However, I can't find any details on how or if they 'unbind' so that this channel can reset, and the general mechanism of this occuring. Certainly, the pre-synaptic cell and enzymes have mechanisms to reduce the concentration of neurotransmitters in the cleft, but I don't see how this causes the neurotransmitter molecules to unbind and therefore allow the channel to be activated again. Any details on this mechanism or whether such a mechanism actually exists would be of great use. Thanks. --Lynto008 03:20, 6 October 2005 (UTC)

You are reminding my of the most boring part of by biomed courses :) I just whipped out my copy of Human Physiology (Vander, Sherman, and Lucino).

If memory serves, unbinding depends on the type of ion channel. [Ligands] "produce either an allosteric or covalent change in the shape of the channel protein. Such channels are termed "ligand-gated channels, and the ligands that influence them are often chemical messangers" (116). Those channels are often further subdivided. What turns the channels "off" depends on the type. It's often either the unbinding of the ligand, or a messanger lipid, or another enzyme ligand, 'etc. →Raul654 03:31, 6 October 2005 (UTC)

So when its said that the ligand 'binds' to the receptor, what is really meant is that it 'triggers' the receptor by changing it, rather than actually attaching? More like the ligand turns on a switch than acts like a key? Because the way that the article Neurotransmitters (and just about everything else i can find on the internet) puts it, "The neurotransmitters... bind to receptors.", which to me seems to imply that it attaches somehow and would remain on the channel triggering it until it is somehow cleaved off. I know that this seems a bit pedantic but to someone who is trying to grasp these concepts, it certainly makes a huge difference. Is it true that the ligands don't really 'bind' per se and that there is actually a distinction? If so, this needs to be mentioned somewhere in wikipedia. Thanks again. --Lynto008 07:50, 6 October 2005 (UTC)

What you are asking is really not biology, but more physical chemistry ;)

A ligand is, by defintion, something that chemically binds to something else. Neurotransmitters are ligands that bind *VERY WEAKLY* to receptors (ion-gated channels), meaning it takes very little energy to break such bonds. The process of binding causes the channel to change shape, allowing stuff to pass through it. However, the weak bonding means that it's very easy for the ligand to pop right back off – possibly even caused by thermal energy (remember, everything is vibrating very fast at the molecular level due to heat -- imagine trying to hold onto something slippery in the middle of an earthquake). →Raul654 08:00, 6 October 2005 (UTC)

Nevermind – I looked up allosteric. Means binding. Duh. --203.206.109.81 07:58, 6 October 2005 (UTC)

Technological trends in information systems

What are the key tehcnological trends that heighten ethical concerns?

I am taking "heighten ethical concerns" to mean "increase people's attention to the ethical aspects of their choice of behaviors." The key technological trends that allowed people to be aware of choices of behavior and to have the time energy and tools to think about ethics were were agriculture, hunting tools, food storage technology, and communication and recording technologies. If you mean something else by the phrase "heighten ethical concerns" please explain. alteripse 03:15, 6 October 2005 (UTC)

You might also educate yourself about the US law commonly called Sarbanes Oxley which imposed accountability standards on a wide spectrum of corporate and other entities doing business in the USA, in the wake of the accounting scandals that led to some of the largest companies in the world going bankrupt. These new regulations also imposed new rules on the information technology aspects of those companies, non-profits, unions, etc. that some people label as being ethical standards, and others label as additional money making sources for the lawyers, in a nation that is by the lawyers, for the lawyers and of the lawyers, with all the other residents being to provide the income to the lawyers. AlMac|^(talk) 04:59, 8 October 2005 (UTC)

longest ship in the world?

The best I can find is an entry in the middle of this section: A.P. Moller-Maersk Group#1993 – 1999 : bigger and bigger. -- SCZenz 03:39, 6 October 2005 (UTC)

• Seems to be that or the Queen Mary II. --jpgordon∇∆∇∆ 03:53, 6 October 2005 (UTC)

Unless the QMII's length is severely rounded, the transport ship I linked to has it by 1.9 m. -- SCZenz 03:58, 6 October 2005 (UTC)

Just a bit of trivia; the Great Eastern was built a century and a half before that but was almost 2/3 the size of these ships. Truly humungous for that time. DirkvdM 14:28, 6 October 2005 (UTC)

Queen Mary II is the longest cruise liner at 345 m LOA; Sovereign Mærsk is perhaps the longest container ship 346.9 m. But a number of supertankers are much bigger, for example, Knock Nevis, 458 m. Gdr 20:25, 6 October 2005 (UTC)

• Though it barely counts as a ship -- more like a storage facility these days! The article does a good job of describing Knock Nevis and its twisted history. --jpgordon∇∆∇∆ 21:54, 6 October 2005 (UTC)

Uranium 238 decay chain

Is the information listed in Decay chain correct?

Should Uranium 238 decay into an alpha particle, Thorium 234 AND two electrons?

Giving off an alpha particle, plus two electrons, would change reduce the number of nucleons by four and leave the charge unchanged. This would result in U-234, as the page says. So it's at least self-consistent. The decay you indicate has a charge imbalance, unless I misunderstand. -- SCZenz 03:56, 6 October 2005 (UTC)

The alpha particle is a helium nucleus, which has two protons and two neutrons in it. Thus, the U-238 loses two protons, two electrons, and two neutrons, and so charge is balanced. --Borbrav 00:32, 7 October 2005 (UTC)

Yes and no. The nuclear decay of U-238 is by loss of an alpha particle to give ²³⁴Th²⁻: the thorium nucleus is not sufficiently close to hold on to the two electrons it has inherited and these are lost to the environment. See also electron affinity. Physchim62 15:47, 7 October 2005 (UTC)

Atoms and molecules

• In the absence of a specific question, I would suggest our articles on Atom and Molecule. Capitalistroadster 04:23, 6 October 2005 (UTC)

Sun & planet gear & epicyclic gearing

Does anyone know the connections between the sun and planet gear and epicyclic gearing. I don't know whether the later is a 'new' name for the former or developed from it or if they are unrelated but share some terminology? Any help would be much appreciated. AllanHainey 07:52, 6 October 2005 (UTC)

The original sun-and-planet gear setup involved only two gears, as stated at that article. What I've read (I don't remember where) is that it was invented for the specific reason that the invention of the steam engine had created a need to convert reciprocating to rotary power, and someone else had already patented the simpler approach of using a crank for that purpose. This would suggest that the more general epicyclic-gearing arrangements shown in that article were developed independently, for applications where this actually was the best form of gearing; but I don't actually know. --Anonymous, 01:30 UTC, October 12, 2005

Rules of significant figures involving addition.

The rule for rounding to significant figures for addition is to round to the least number of decimal places involved. However, if the example were 1.01 + 3. + 1.1 would the rounding go to 4 or to 4.1? AKA, does a figure with no decimals mean to round to no decimals, or is it the least after that?

This came up in class yesterday and I was just wondering what the specific rule for this was and any reasoning behind this. Thanks.

That would depend wether that specific number with no decimals is an exact number or not. For example, if my journey from home to school took 1.75 km then I would travel 2 * 1.75 = 3.50 km from home to school and back. If I have a yard of 2 m by 3.71m the total surface area would be 2 * 3.71 = 12m7m². --R.Koot 14:26, 6 October 2005 (UTC)

Ah, trick question! 1.01 + 3. + 1.1 = 5.11 (not 4.whatever). As to how that should be rounded off, I'm a bit rusty, but I assume that the fact that there is a dot behind the 3 means that it's not exactly 3, but you don't have the numbers behind the dot, so you can't use those of the other numbers, so the answer is 4. (with a dot). As to whether that should be rounded off before or after the calculation, I forgot, but in this case the answers are the same. DirkvdM 14:40, 6 October 2005 (UTC)

Rounding for numbers of known higher precision should be done after calculations so as not to propagate rounding errors. Think of adding 2.7 4.6 2.55 and 3. Rounding before the addition causes the rounding errors to add getting the erroneus answer of 14, when it should be 13. It's a bigger deal with multiplication of course. - Taxman ^Talk 14:27, 7 October 2005 (UTC)

And R.Koot should go get his tuition fees back. 2 * 3.71 = 12 m ? And I'm not referring to the omission of the '²'. DirkvdM 14:40, 6 October 2005 (UTC)

Uhhh... I don't even know what I meant there? --R.Koot 23:21, 6 October 2005 (UTC)

Thanks, Dirk. THat answered my question.... And nice catch on the 3 + 1 + 1 = 5... Oops!

Whenever you add, you keep all and only the decimals which were known in all of the numbers you were adding. i.e. 2.45+3.891=6.34, not 6.341. --Borbrav 00:22, 7 October 2005 (UTC)

Rounding rules have different schools of thought based on the context of what is being arithmeticed.

Suppose the military needs to move a certain volume of men and equipment, and the math comes out that to do this, they need 11.2 army trucks, the answer is not 11 trucks but 12, because there are cases where you always round up. AlMac|^(talk) 05:02, 8 October 2005 (UTC)

English name of pen&paper game

The game is popular among Russian students. The rules are described here. "Pests" is a code-name. It's called "клопы" (a kind of pest) or "тараканы" (roaches) in Russian. I hope someone knows how it's called in English.  Grue  13:38, 6 October 2005 (UTC)

The rules sound conceptually similar to several other games I am familiar with:

• The game of GO, which is an oriental guerrilla game sometimes considered to be the mental equivalent of CHESS, and several played on same kind of grid, with race to get some number in a row.
• The game of LIFE which can be played solitaire, or in competition. There are variations on the game of LIFE, such as VIRUS, in which you design simple algorithms for growth of your PESTs to try to eat away at the enemy LIFE. I think some nuts have taken that interest into the design of computer viruses.
• Then there are a number of ECOLOGY games played using different colored multi-sided dice (more than 6 sides) where the number on top represents the population of that animal or plant, which eats adjacent as food, leading to an increase in the population, but if there is not enough food, the population decreases.

AlMac|^(talk) 18:39, 15 October 2005 (UTC)

This game "Pests" seems similar to (but not the same as) the game Conquest, which is a common video game in my area. -Juuitchan

So it seems there's no English equivalent. That's quite strange because I remember playing it in school in Perm about 8 years ago, and I've seen it played last week in Moscow. So it must be quite widespread. The game's quite interesting, and the rules are quite simple. I wonder why there isn't anything similar.  Grue  16:56, 17 October 2005 (UTC)

depersonalization

What is the original reference for the information contained on your website concerning depersonalization, particularly the information regarding suicide ( as well as the general information provided). I have seen this exact wording on several other websites, but no references for the information.

Thank you,

Donna McCleary

• You can contact the people who contributed to the article, each of them is listed in the article's edit history. The links in the article appear to be authorative on the subject, so you might want to visit those and ask the people there for reliable references too. - Mgm|^(talk) 15:50, 6 October 2005 (UTC)

helium

where did the name helium come from?

• From Helium#History: "He and English chemist Edward Frankland named the element after the Greek word for the Sun god, Helios, and, assuming it was a metal, gave it an -ium ending (a mistake that was never corrected)." – Mgm|^(talk) 15:52, 6 October 2005 (UTC)
• If I remember rightly it was named after the sun because it was discovered after observing the spectrum of the sun's light during an eclipse.--stib 03:31, 13 October 2005 (UTC)

Heroin In Food

Until this AM I could not understand why I am having so many problems with my? Now I do.The reason I was asking about info. on ingesting heroin in food,is because that is how our daughter,Shenel,was murdered.People do not eat heroin,so we can find no info.on Toxicological Findings.That is ALL this is about!The FACTS!Any & all we can possibly get.As far as I know,and I have researched alot of drug sites,nobody knows.We did find alot of very good info.here,so I thought maybe you could find the answer to our ?.I just wish you would of let me know there was a problem with our ? instead of just deleting it.We'd still appreciate an answer,if you can find one.Our hearts are broken and she left behind two children.Eric was 4 , and Alyssa was 5 weeks old.Someday,if we can,we want to be able to explain all of this to Eric.Alyssa is with the man who killed her mother,so we lost her too.The sites we have gone on in New Zeland and Australia,which have done alot of studies on heroin,have made us realize the U.S.has alot to learn.Because of their lack of knowledge,this man got away with murder.It happens more often than you would ever believe,and we are all paying the price.We would be so grateful if you can help us?If not, I will know when I come back and see I have once again been deleted.I do want to thank you for all the good info.you did provide us with and say good-bye for now. Toni

Toni, I sympathise with your situation, talk about stressful. No one has deleted your questions. Your first post with replies is still here, but you need to scroll up a long way to find it. Likewise your second post is still present. Realise that new topics are being added to this pages rapidly. David D. (Talk) 18:28, 6 October 2005 (UTC)

Regarding Heads

There was some talk around here a few days ago regarding the possibility of head transplants. The general consensus seems to be that there is no real reason a head could not be transplanted onto a donor body and live, albeit as a quadriplegic. So the question that occurs to me is this: Is the classic sci-fi/horror staple of a severed head being kept alive, artifically, possible? What about the even more cliched "brain in a jar"? With an oxygenated/nutrient enriched blood supply, under strictly controlled hospital conditions, is there any reason why a human head could not be kept alive, other than ethical ones? Brian Schlosser42 18:32, 6 October 2005 (UTC)

Should be fine in theory.

But very difficult in practice. Certainly well beyond the current state of the art. See the Wikipedia articles on head transplants and whole-body transplants. Gdr 20:00, 6 October 2005 (UTC)

I'm not sure it would be that difficult in practice, certainly a non-trivial proposition, but given the success of primate head transplants, I would think that simply keeping a human (I presume that the questioner is talking about humans) head alive would be well within the current state of the art. The major obstacles to actually doing this would be ethical, not medical.

Funny that only a brain transplant is also called a whole body transplant. The same could be said for a head transplant I'd say. Also funny that the article on the former nevertheless goes on to speak about tranplanting the brain to another body. The alternative name exists for a reason (if one assumes personality resides in the brain). DirkvdM 20:40, 6 October 2005 (UTC)

The success of Dr. White's head transplants is, I think, rather overstated by our article. In the best cases, the head survived for several hours and showed signs of consciousness. Gdr 20:45, 6 October 2005 (UTC)

word password recovery

There is a free or open source word password recovery program, but I have lost it – does anyone know it? Thanks!

One program that is free for 30 days is Elcomsoft Advanced Office Password Recovery. I haven't tried it so I can't vouch for it, but it might get you out of immediate trouble. There are lots of other programs but this was the first I found which appears to have a fully functional demo available.-gadfium 03:05, 7 October 2005 (UTC)

Elements

What is the importance of Iron?

• Reading Iron would be a good start. It's the final end-product of nuclear fusion, and steel is made from it. I think that's enough hints to start your essay! ;) -- SCZenz 21:38, 6 October 2005 (UTC)
• Lets not give short shrift to its role in hemoglobin. There is also its role in that time... what was it called... oh yeah, it was the Iron Age. Qaz ^(talk) 06:25, 8 October 2005 (UTC)
• Iron is one of the few metals we know of affected by magnetic fields. Rob Church ^{Talk | FAD} 15:49, 9 October 2005 (UTC)
• If you don't use it your clothes end up wrinkled. DJ Clayworth 17:58, 7 October 2005 (UTC)
  • Unless you have decent clothes that don't wrinkle. DirkvdM 09:32, 8 October 2005 (UTC)
    • Or use a tumble dryer, and get them out quickly enough afterwards. Certain clothes can be hung to allow the wrinkles to fall out too. Rob Church ^{Talk | FAD} 15:49, 9 October 2005 (UTC)
      • The problem with this approach is that the fallen wrinkles collect at the bottom of your closet. If you don't wear socks or slippers, the wrinkles can then be transferred to your skin. (Ironing avoids this problem; the high heat inactivates wrinkles, which can then be transferred back down the powerlines for safe permanent disposal by the electric company.) TenOfAllTrades(talk) 16:10, 9 October 2005 (UTC)

Guys,guys, come on it's a serious question...without iron the wheels would fall off my truck...I wouldn't even have a truck...

Look at any skyline of a major city today.

Look at pictures of city skylines from 100 years ago.

Consider how it became possible to build them so much higher, thanks to modern development of metals and other building materials, and consider what they might look like 100 years from now ... will space elevators become commonplace?

AlMac|^(talk) 09:09, 10 October 2005 (UTC)

Consider the importance of magnetism to the development of many modern conveniences, such as computers. AlMac|^(talk) 09:10, 10 October 2005 (UTC)

Apparently this is another essay question (header added subsequently)

State two ways in which a singled-celled organism, such as an amoeba, and a human body cell are alike.

Any number of properties in cell might suffice, but my two favorites are:

1. They're both smaller than a breadbox.
2. Neither one, under most circumstances, contains very much uranium.

If I were you, I would write your essay based on something else, though. ;) -- SCZenz 22:22, 6 October 2005 (UTC)

See our article about eucariontes. --User:Mdob | Talk 20:43, 17 October 2005 (UTC)

Biology

Plants produce cholorophyll to capture the energy from the suns ray's and take in carbon dioxide from the air, and water from the soil. What characteristic of living things does the show?

Their tendency not to do their own homework. (LOL, great answer !)

In seriousness, you should ask a more specific question. That describes lots of characteristics of living things; I suspect that only one of them, however, is on your vocabulary list for the week. RSpeer 22:23, 6 October 2005 (UTC)

You might look at Life, in particular Life#A conventional definition. -- SCZenz 22:24, 6 October 2005 (UTC)

Adaptation?

Ears

What animals have ears on the sides of their body? ...rabbits on my bumper--Eye 20:28, 9 October 2005 (UTC) and What animals have ears on their antennae? ...flies on my windscreen--Eye 20:28, 9 October 2005 (UTC)

--24.214.167.141 22:57, 6 October 2005 (UTC) Should this be deleted?

Smelling Extract

I am battling a stopped up nose and I once heard that smelling peppermint extract could break up the mucus. Does this work? Would sniffing the extract fumes kill brain cells? Could it get me high?

Your brain cells are dying as we speak anyway, and I suspect wine would do more damage to them than peppermint. Why not try it and report back here?--inks^T 04:47, 7 October 2005 (UTC)

I suggest you visit a pharmacy, sometimes called a drug store (that sells legal drugs) and direct your question to the pharmacist there. Typically there are scores of different brand names of remedies, at very reasonable prices. AlMac|^(talk) 05:07, 8 October 2005 (UTC)

Cough drops create substantial vapors, that will serve such a purpose, while you suck on them. I suggest a menthol-eucalytptis blend, that really does the trick. StuRat 05:34, 9 October 2005 (UTC)

One up each nostril should work --Eye 20:25, 9 October 2005 (UTC)

how do telescopes work?

Optical telescopes use a series of lenses to magnify distant objects, the same way a microscope does. Other types of telescopes are a bit more compliated. →Raul654 04:23, 7 October 2005 (UTC)

• Our Telescope article should be of some assistance as should the articles on specific types of telescope listed at the bottom of the telescope article. Capitalistroadster 05:01, 7 October 2005 (UTC)
• Also, if you typed this query into google, your second hit would've been this page from HowStuffWorks.com which has some info which may help you if you find the Wikipedia article too difficult to understand. - Mgm|^(talk) 16:31, 7 October 2005 (UTC)

Why do some noises cause goosebumps?

When someone scrapes their fingernails against a chalkboard, I get goosebumps. What is the reason in this?

I'm not sure exactly why sound initiates goosebumps, but the reaction is vestigial. Back when humans had hair covering their bodies, the reaction which is technically called piloerection, was intended to make ourselves appear larger, much like a cat does today when they are frightened. My guess would be, that a scary sound also triggers this reaction (like for instance the roar of a lion). Hope that helps. - Cobra Ky (talk, contribs) 17:18, 7 October 2005 (UTC)

medical term

What is meant by 'osteophytic lipping'?

Rgds, --Ciesse 203 13:52, 7 October 2005 (UTC)

Osteophytes are small projections of new bone growth or thickening. Lipping is a description of an x ray appearance. We need more context to interpret this, or you can ask your doctor. alteripse 19:46, 7 October 2005 (UTC)

I can actually answer this. They are indeed bony projections, usually found on the outer edges of articular surfaces of joints. Occurs in people exposed to heavy loads (eg. slave labourers) and elderly. Yay! My BSc in Anatomy was useful for something! This calls for a party!.....--inks^T 02:46, 8 October 2005 (UTC)

How do protons(+) not repel eachother...and....

how do electrons(-) not stick together with protons(+)??

For the first question, this is the strong interaction – it's effectively nonexistent at long distances, but over very small distances (like those inside an atomic nucleus) it's very powerfully attractive. This is more powerful than the electromagnetic force, so it holds them together. See atomic nucleus. Think of it this way – two positive poles of a magnet will strongly repel each other, but if you duct-tape them together they won't actually be able to break apart, because the tape is stronger than the magnetism.

For the second question, think of them as orbiting the nucleus very fast – they're falling toward the atom, yes, but satellites are also always pulled towards the earth by gravity, and they don't land on the surface. This isn't a very accurate description, but you might find it helps make sense of the problem. Shimgray | talk | 14:48, 7 October 2005 (UTC)

Two protons, with no neutrons present, actually do repel each other. The strong nuclear force only helps in a nucleus where neutrons are present also. By the way, these are great questions--they were central mysteries of physics for much of the early 20th century. -- SCZenz 15:35, 7 October 2005 (UTC)

Also, remember that an electron is not a thing (like a little ball), but more like a wave, or ring of evergy around the nucleus. It has to remain at a specific distance in order to orbit around the nucleus, determined by it's wavelength. --Mary

Electrons are most certainly NOT "ring[s] of [energy] around the nucleus". Rangek 14:52, 18 October 2005 (UTC)

A good question to ask is how do neutrons help keep protons together in cases where the absence of neutrons woudl cause the protons to repel each other? Next question is why are neutrons stable in the nucleus when protons are present, but decay into a hydrogen atom when alone?

Those are also good questions.

1. The answer to the first is that the strong force between the proton and neutron is stronger than either the proton-proton or neutron-neutron force, and is enough to bind a proton to a neutron. So you can think of a nucleus as being more bound by the proton-neutron attraction than anything else (although the other interactions contribute too, they wouldn't be enough by themselves).
2. The answer to the second, I think, has to do with energy. A free neutron has more energy than its decay producs (e.g. a proton, an electron, and an antineutrino). But for most nuclei containing a neutron, the energy is actually lower as things are now than it would be if the decay happened. (Because of nucleus stability/bond strength issues in question 1.) Thus a free neutron decays, whereas neutrons in nuclei don't. Interestingly, nuclei with too many neutrons will have lower energy if a decay happens, and there the neutrons do undergo beta decay.

Hope that helps! -- SCZenz 22:41, 7 October 2005 (UTC)

Protons DO repel each other, but in the nuceus of an atom that repulsion is overpowered by the more powerful yet shorter distance acting force called strong interaction. Electons DO stick to the nucleus (protons and neutrons) of an atom; they are just millions of times BIGGER than the nucleus (visualize cotton balls glued to BBs). At the particle level, heavier things are smaller and lighter things are bigger due to the wave nature of things. The electrons get as close to the nucleus as they can, and their wave nature describes a shape looking like a donut or a sphere or a set of teardrops or other shapes (these are called orbitals, altho nothing is really orbiting). Talk about electrons orbiting is a heuristic in that it is a useful model without being accurate. WAS 4.250 22:04, 10 October 2005 (UTC)

Protons and electrons can "stick together". See electron capture. Rangek 14:57, 18 October 2005 (UTC)

Perl or Python?

I'm a budding computer programmer with free time on my hands. Is it better (more useful / more marketable in the job market) to learn Perl or Python? Or something else? I currently know Java and Prolog. Thanks!

Mary

It's a bit of a tossup. Perl and Python both do pretty much the same thing in about the same amount of code at about the same speed. The primary differences are that (1) Python is far, far easier easier to learn and to read (it's easy to read someone else's python code) while Perl is (as a colleague of mind humerously noted) a "write only language" (2) On the other hand, Perl has been around three times longer than Python, and is more entrenched in the market. So where the job market is concerned, Perl is probably more attractive from that perspective. →Raul654 22:48, 7 October 2005 (UTC)

Python is fun. Perl is not. I'd go with the former. Garrett Albright 01:34, 8 October 2005 (UTC)

Do a search for Perl and Python on a recruitment website and see which ones look most interesting. Perl jobs tend to be mostly Internet service providers (and spammers if you're evil). The mobile phone industry is starting to use Python apparently, and I agree that it's nicer to use than Perl. You can also play with Ruby, which is somewhere in the middle, or Lisp if you're a follower of Philip Greenspun and Paul Graham. Ojw 15:03, 8 October 2005 (UTC)

Nonsense. How is Perl "not fun"? How do you quantify a language being "fun" anyway? Dysprosia 04:08, 9 October 2005 (UTC)

Oh, I won't lie and say that I wasn't being subjective. But the fact remains that Perl has a much higher level of entry than any other major language out there; it's like you can't help but write obfuscated code. The OP said she already knows some other languages, so I'd bet she could pick up Python in a snap because it's quite easy to "read." Perl, not so much. And since productive programming is fun programming, she'd be able to start having fun in Python much sooner, I'd bet. Garrett Albright 08:10, 9 October 2005 (UTC)

I doubt that. To do something in Perl requires the same basic knowledge to do the same in Python. Perl is quite easy to read too, if you write it in a certain way. (It's not that I'm trying to be Perl-partisan here, I'm not, I just feel that some criticism of Perl tends to be overrated.) Dysprosia 11:34, 9 October 2005 (UTC)

Why do men have nipples?

Ya, I said it! But I would seriously like to know. - Cobra Ky (talk, contribs) 17:21, 7 October 2005 (UTC)

Men actually have complete breasts, not just nipples...they are just underdeveloped. --Phroziac^(talk) 17:27, 7 October 2005 (UTC)

Well, usually! Manboobs! — ceejayoz ^{★ .com} 03:35, 9 October 2005 (UTC)

Why? - Cobra Ky (talk, contribs) 17:28, 7 October 2005 (UTC)

I think sexual differentiation could answer some of your questions. Most male and female organs develop from the same undifferentiated fetal organs; they simply develop differently under the influence of hormones. Female hormones stimulate the development of breasts during puberty, so women's proto-breasts develop while men's don't. — Laura Scudder | Talk 18:13, 7 October 2005 (UTC)

• Stephen J. Gould's essay "Male Nipples and Clitoral Ripples" is a pretty good essay on the subject. I think it's in Bully for Brontosaurus. --Bob Mellish 18:20, 7 October 2005 (UTC)

The short answer is that there has been no biological reason to eliminate them. The genes for nipples are very ancient ones common to both sexes of all mammals and are not carried on the Y chromosome. The basic equipment of a nipple is biologically cheap. It is made operational when needed by hormone signals. A defect of nipple or breast development carries little reproductive penalty to a man but a strong reproductive penalty to the other 50% of the population, so nipples continue to be advantageous and evolutionarily conserved. An intelligent designer of course would not bother to design a male with them: this type of trait is far better explained by evolution than by any competing hypothesis. alteripse 19:43, 7 October 2005 (UTC)

• But what if that "designer" was intelligent but lazy? Ha! And who was his/her manufacturer if that designer only did the design and ordered the products from an overseas supplier? Anyway, if he/she was so intelligent and also predetermined our destinies, all nuns and priests would have no sexual organs at birth. The only possible explaination: This designer is lazy. -- Toytoy 09:54, 18 October 2005 (UTC)

The biological reason to eliminate them is not strong enough to cause them to be eliminated, much like the appendix.

Thanks for the answers everyone. I believe I thoroughly understand now. The reference to intelligent design was quite interesting as well; another score for evolution theory. - Cobra Ky (talk, contribs) 23:05, 7 October 2005 (UTC)

I think User:Alteripse is giving the field of intelligent design far too much credit by supposing it makes any testable claims about the nature of the designer. Gdr 13:12, 8 October 2005 (UTC)

There is an interesting parallel in industry, where it is frequently cheaper to make everything the same, even if that means some "additional equipment" is included that was not "ordered". For example, circuit boards are often built with everything and then those options the customer doesn't want are burned off or otherwise disabled. It doesn't seem intuitive that this is efficent, but the cost of producing many different types of circuit boards apparently is more than the cost of destroying unwanted components. StuRat 05:12, 9 October 2005 (UTC)

Men have nipples because in the early stages of developments inside the womb Males and females are basically indistinguishable. In other words, we all start out from the same "template".

Well yes, but the more interesting question is why we all start out the same. It would also be possible for male bodies to eliminate nipples later in life, much as we lose baby teeth, if there was some value to doing so. StuRat 13:48, 14 October 2005 (UTC)

Can Big Red gum cause permanent tongue damage?

If you cover your tongue with Big Red chewing gum and stick it out of your mouth for an extended period of time could it cause permanent damage?

• I am not sure what mechanism of harm is worrying you, but the surface of the tongue heals even faster than the surface of the skin. alteripse 19:44, 7 October 2005 (UTC)
  • Really? I didn't knew that. Could you add what you know to tongue? ☢ Kieff | Talk 23:02, 7 October 2005 (UTC)
    • It's just that the tongue and inside of the mouth are mucous membrane tissue. Although not as tough as epidermis, mucosal membranes have a blood supply that is more plentiful and closer to the surface and have a higher density of immune cells and are more resistant to wound infection. I suspect (off the top of my head) that there are higher densities of precursor cells and faster responses to injury in mucosal membrane compared to skin. In practical terms, this is why doctors in emergency rooms dont even bother to suture cuts in the inside of the mouth unless the tongue is almost severed (I am exaggerating only a bit here). alteripse 00:55, 8 October 2005 (UTC)

• Yeah, probably not. It is unlikely any worse than burning one's tongue on very hot food -- it might hurt like an SOB for a few days but it heals pretty quick. --Fastfission 19:47, 7 October 2005 (UTC)

Frosty Question

On bright, still, autumn mornings just before the sun comes up I notice that the dew on my car windscreen is not frozen and then as the sun rises above the horizon the dew freezes. Is it possible that the solar wind passing the edge of the earth can cause the tempter to fall? I have noticed this happen on dozens of occasions over the years. Is there a link? --Eye 20:31, 7 October 2005 (UTC)

The short answer to your question, I believe, is no. Sunlight isn't going to make anything on earth colder. Sadly, I have no idea what actually is going on. -- SCZenz 23:07, 7 October 2005 (UTC)

If you think about it, the Earth doesn't start warming up from the Sun's rays untill well after sunrise. Thus, it could be just that the Earth is still cooling down, and the sunrise and freezing are unrelated. --Borbrav 04:01, 8 October 2005 (UTC)

Dew freezing on the windscreen is a rare occurance in my part of the world, but I do know that in the middle of winter (in my location of Perth at least) the day's lowest temperature occurs about 20-30 minutes after sunrise so I wouldn't think it's a solar wind thing.--Commander Keane 06:11, 8 October 2005 (UTC)

You spend your sunrises looking through a car window? Did you cheat on your wife and get kicked out of the house? :) I wish :-) --Eye 21:16, 8 October 2005 (UTC)

But more seriously, I'm thinking about the influence of wind. I've often noticed that around sunset/rise the air suddenly becomes very still. Maybe a slight wind prevented the previous formation of frost.

This makes me think of something else I've often noticed. When you boil water and then turn off the gas (if you use gas, that is – an electric stove works too slow for this) you suddenly get (more) steam. The reason for that, I assume, is that previously the hot air rising along the sides of the pot prevented the steam from forming. But if you turn off the gas, the water at first still boils and keeps on saturating the air. And the saturated air finally gets a chance to form steam. DirkvdM 18:01, 8 October 2005 (UTC)

Maybe frost isn’t the right word. What happens is that the dew freezes. The drop in temperature is very slight but enough and occurs after the sun has risen. A drop in the wind might be a more feasible answer but that is so with most frosty days. Maybe there is a weather person out there? --Eye 21:16, 8 October 2005 (UTC)

Shortly after dawn the sunlight is coming in at such a shallow angle that it provides little heating, such that the thermal loss into space is greater. That means the temperature, on average, will continue to drop until the Sun gets to a more respectable angle. I said "on average", since local weather fronts can easily overwhelm this slight effect. StuRat 05:03, 9 October 2005 (UTC)

I had an interesting frost phenomenon on a car of mine. Frost would form on the hood then melt as the air warmed up, except for the areas of the hood with the cross supports under them, since they kept those parts of the hood cool a few minutes longer. The result was a frost X-ray of the hood ! StuRat 05:19, 9 October 2005 (UTC)

carbohydrate chart

How many grams of carbohydrate are in various common foods?

• Any site on the Atkins diet would keep such a list. You'd have to be more specific about which foods you're talking about if you want a useful answers from us. - Mgm|^(talk) 22:12, 7 October 2005 (UTC)

Google carbohydrate content or carbohydrate list. You will find dozens of such lists, if not hundreds. alteripse 00:49, 8 October 2005 (UTC)

This site provides a fairly comprehensive list of nutritional info for many foods:

http://www.nutritiondata.com

StuRat 04:58, 9 October 2005 (UTC)

carbon trading

WHAT IS THE SCOPE FOR INDIAN INDUSTRIES IN CARBON TRADING?

BY, SRUJANA FINAL YEAR B.E(CSE) PLEASE GIVE ME ANSWER TO MY MAIL-ID

• I've also seen this question in the Humanities reference desk, please only post it in one reference desk subsection. - Mgm|^(talk) 08:15, 8 October 2005 (UTC)
• Srujana,

I have removed your e-mail as answers are not returned and you will start becoming more of a target for spam. Our Carbons emission trading article is a good start and our Economy of India article should give you some idea of the challenges. This release from the International Emissions Trading Association states that India has started trading [27]. These newspaper articles show that Biofuel and tree plantations are targets see [28] and [29]. Capitalistroadster 05:32, 9 October 2005 (UTC)

I'm not sure what you are refering to specifically but Kyoto Protocol doesn't require developing countries such as India to restrict its carbon emissions. Only those of Annex 1 in the Protocol that are required to cap their emissions. __earth 14:37, 11 October 2005 (UTC)

Smoke

Is there a way to add a color to smoke? For example, adding a substance to a cigarette to colorize the smoke. Is this possible?

Sure, but most people think it would make cigarettes even more offensive. alteripse 12:31, 8 October 2005 (UTC)

Fireworks? DirkvdM 13:44, 8 October 2005 (UTC)

See the "common pyrotechnic compounds" section of our fireworks article. Shantavira 16:56, 8 October 2005 (UTC)

Note that you don't want to add most of those compounds to a cigarette. Doing so would tend to make them much more rapidly and efficiently deadly than they already are. Note as well that those compounds will give a coloured flame, but won't typically have an appreciable effect on the smoke. TenOfAllTrades(talk) 03:24, 9 October 2005 (UTC)

There are some colored gases, like the purple of iodine or the green of chlorine, but those aren't the type of things you would want to inhale. StuRat 04:51, 9 October 2005 (UTC)

The question mentions cigarette smoke only as an example, so the answer should not focus on that. And certainly not the act of smoking, because that can hardly be the intent, unless it's a machine that smokes for some research or something. What is the reason for the question? DirkvdM 13:06, 9 October 2005 (UTC)

If you're asking because you want to film or photograph the smoke, then you could use coloured light to give the smoke a tint. Ojw 13:27, 9 October 2005 (UTC)

Generic Drugs

Is there a real difference between a generic and brand drug? I know they have to have the same active ingredient and have to be the same quality and everything, but then why do some doctors insist that a patient takes the brand and not the generic version? And why do so many people claim that the generic version of a drug do not work?

Some time ago there was a discussion in Dutch politics if doctors should not be forbidden to prescribe those unnecessarily expensive drugs and if national health insurance should cover that (or only restitute the normal price). I don't know what the outcome was (or indeed how informed the politicians were). Doctors may receive money for pushing certain brands. And if the drug is sold by themselves, they will likely make a bigger profit from a more expensive drug (which is why that is not the way it works in the Netherlands). People in general may make such claims because with health one should not take risks and therefore the more expensive option should be chosen (as if that is ever any guarantee – especially when you don't really know what you're buying). But now I'm only guessing. It's comparable to the inflated prices of condoms and funerals – not the sort of thing with which people are inclined to complain about the price. Fyi, I pay about 0.10 € each for my condoms. Well, for that I need to buy a gros, but they keep for years and the point is that it's a good indication what a reasonable price would be. DirkvdM 13:58, 8 October 2005 (UTC)

Is there a difference? In a word, sometimes. Most of the time for most drugs and most people a generic will work as well at a lower price. For some drugs in some people the difference between a generic and brand name may more than trivial. The problem is that it is difficult to predict ahead of time. alteripse 05:51, 9 October 2005 (UTC)

Our Generic drug article states that they are bioequivalent to the brand drug. However, in 50% of cases there is no generic drug as the term of the patent has not expired. There may also be a newer drug which may be more effective but may also be more expensive. In short, it depends on the circumstances. Capitalistroadster 06:11, 9 October 2005 (UTC)

Postural Drop related to Scleroderma and Kidney Disease

Dear Wikipedia Volunteer,

I have just found out about your service in a Sydney newspaper and am very excited at its potential.

Having just searched in Wikipedia for "postural drop" no results were available, although I am aware that Google, at least, does provide some references.

I sincerely hope that some of your readers, or whoever, can throw some light on this serious and deilitating condition.

Kind Regards, Arthur Major --203.164.32.81 07:19, 8 October 2005 (UTC)

See orthostatic hypotension. alteripse 12:32, 8 October 2005 (UTC)

WBC Booster

Sorry if this is a repeat post, but I accidently posted this in another category.

I know there are drugs that some athletes take to increase their red blood cell count, but are there any drugs that increase the number of white blood cells?

• It's been answered at Wikipedia:Reference desk/Miscellaneous#WBC Booster. - Mgm|^(talk) 08:25, 8 October 2005 (UTC)

Coming out with generics

I was wondering why sometimes it takes so long for a generic drug to come out. I read something about the patents for allegra and I think flonase expiring and it was about a year ago I think, but generic versions are not available yet, why is this?

• Even when derived from the patented brand, generic drugs still need to do research to use the information to make a useful drug after which they need to have it tested and get all sorts of forms from government and health organizations. It's just a long, long process. - Mgm|^(talk) 19:37, 8 October 2005 (UTC)
  • It isn't always profitable to do so, either, especially if the brand name drug is fairly cheap already. — ceejayoz ^{★ .com} 03:33, 9 October 2005 (UTC)

Muscles wasting

My cousins muscles are wasting away and the doctors told him he will eventually be in a wheelchair. The doctors also said there are no drugs currently that could help him and the only thing he could do is physical therepy. I was wondering if something like steroids would help him out? I know they are illegal and arent very safe or healthy, but would it work and stop or slow down the wasting of his muscles?

Anabolic steroids are used sometimes for medical purposes, so I think that if they could help your cousin, his doctors would have thought of that too. Why not ask them about it? David Sneek 12:16, 8 October 2005 (UTC)

If your cousin has a muscular dystrophy there have been many clnical trials of anabolic steroids as well as glucocorticoids and growth hormone. They have not been found beneficial and sometimes have accelerated loss of strength. Search Medline for these terms if you want to find out for yourself. The muscular dystrophies are truly nasty diseases with few treatment options except support for most; I am sorry for your cousin. alteripse 12:30, 8 October 2005 (UTC)

• It sounds like Muscular dystrophy probably Duchenne muscular dystrophy to me. In answer to your question, this fact sheet from the Muscular Dystrophy campaign outlines that steroids are being used to treat muscular dystrophy see [30]. I have two young nephews with the disease and the good news is that research in a number of areas is delivering promising results. Wyeth are conducting human clinical trials of a treatment in adult muscular dystrophy see [31] According the National Institutes of Health, there are 13 clinical trials underway for various forms of muscular dystrohy see [32]. There have been positive outcomes in animal trials for gene therapy in recent times as well. Capitalistroadster 07:15, 9 October 2005 (UTC)

This is a nicer answer, with refs, than my gloomy one. Note that the "steroids being used to treat muscular dystrophy" in the MDA ref are glucocorticoids rather than anabolic steroids. The disease and both types of steroids have been well known for about 60 years. I didn't realize anyone was still running trials on glucocorticoids, but I didn't try to look it up. I hope some the cited research changes the traditionally pessimistic picture to which I alluded. alteripse 12:33, 9 October 2005 (UTC)

Pharmacy School

I'm interesting in applying for pharmacy school in the next few years, I was wondering how to increase my chances of getting in. I know good grades and a good PCAT score are important and also volunteering in a pharmacy, but what else can I do to increase my chances of getting in a good school?

Also, what questions do they ask at the interview? Thanks

Here is the same advice I would give if you asked about medical school or veterinary school. Concentrate on your grades, especially math and science. Most of the applicants whose grades and scores are within 10% of the average for last entering class will be offered admission, as will some of those whose grades and scores are below that. The principal purpose of the interview is identify unusual positive or negative characteristics that they cannot easily determine by the paper application, or cannot legally or publicly admit to using. Many of these characteristics are those you don't have control over. Another purpose of having an interview is to introduce a subjective element into the process so that taking one person over another with higher numbers can be justified.

If your grades and scores are at least average for the entering classes for that school, the prinicipal purpose of the in-person interview is to detect a disqualifying characteristic. This may differ widely depending on time, place, and local circumstances. One example might be race. Another might be an inability to hold a basic conversation and communicate. Another might be an appearance that suggests potential problems fitting in with the class and reflecting positively on the school. Another might be an extreme disability or an apparent mental illness. Another might be an indication that you would be unlikely to accept an offer of admission. In other words, the admission is yours to lose by the interview.

On the other hand, if your grades and scores are substantially below average for their usual entering class, the principal purpose of the interview is to look for an undetected asset. This may differ widely depending on time, place, and local circumstance. One example, especially in the US, may be race. Another might be an unusually impressive or attractive personal manner. Another might be to confirm other non-quantitative accomplishments. Another asset might be a family connection with the school or something to convince them you are more likely to accept and complete school than the other below-average candidates. Another might be wealth or political connection that could be of advantage to the school. In other words, a small number of students with well-below-average scores will win admission based on other things detected at the interview.

In other words the exact answers to the questions are not the point; it is the chance to detect other things. Work hard so you are in the first group and don't worry about the interview. alteripse 11:43, 8 October 2005 (UTC)

internet

• You found it. Any questions? Qaz ^(talk) 08:23, 8 October 2005 (UTC)
• By just getting here to ask the question, you must have used the internet. Like the person who asked what is operating system had to ahve used a computer to use the internet to get here to post the question. So we have people driving over the information superhighway who are not familiar with the terminology of the infrastructure involved, comparable to a person who drives a personal automobile, but does not know what a highway is. What is computer literacy coming to? AlMac|^(talk) 15:41, 8 October 2005 (UTC)

Maths: Asymptotic Series

Can anyone help me solve this:

You are given a function

$f(x)=(x+1)e^{\frac {-1}{x}}$.

Find $a\,$, $b\,$ and $c\,$ so that the formula

$f(x)=ax+b+{\frac {c}{x}}+o\left({\frac {1}{x}}\right)$

is true when $x\to -\infty$.

Thank you.

Here's a hint to help you with your homework: consider the Taylor series for $e^{\frac {-1}{x}}$. Gdr 14:00, 8 October 2005 (UTC)

The question makes no sense. How can $ax$ and $o(x)$ be in there both? Anyway,

$e^{\frac {-1}{x}}=1-{\frac {1}{x}}+{\frac {1}{x^{2}}}+...$, so

$f(x)=x+{\frac {1}{x^{2}}}+...$

meaning $a=1\,$, $b=c=0\,$. 82.210.119.82 15:10, 8 October 2005 (UTC)

See our article Big O notation for an explanation of little o notation, but essentially $f(x)=o(g(x))\ \iff {\frac {f(x)}{g(x)}}\to 0\,$ as $x\to \infty \,$. Little o notation is mostly used by mathematicians; a computer scientist would have used big O notation and written $O\left({\frac {1}{x^{2}}}\right)\,$ here (with much the same meaning).

As for your derivation, you've got the Taylor series for $e^{x}$ wrong. Gdr 15:56, 8 October 2005 (UTC)

But if $e^{\frac {1}{x}}\,$, how does $x\to -\infty$ change the thing — in what way is it different from $x\to \infty$?

Chemistry: Small Mushroom Cloud?

I recall seeing a video of a (probably high school) chemistry lab. A teacher poured the contents of one beaker into the contents of another and it bubbled up and over the edge of the beaker and created a small mushroom cloud. What chemicals can be used to achieve something like this and what are the safety precautions surrounding it? Sorry, I can't find the video but thanks in advance. -Haon 14:48, 8 October 2005 (UTC)

It would probably strongly depend on the conditions in the lab, including controlling drafts etc, so it might have just been luck. If you want the gas to fall below the top of the beaker, you'd want the gas to be cooler than the surrounding air, so probably good old dry ice in water would do the trick.

So at a normal room temperature, dry ice combined with water would create a mushroom cloud? -Haon 19:43, 8 October 2005 (UTC)

The main things needed for a visible mushroom cloud are:

1) The gas to rise must be much hotter than the ambient air temp.

2) The gas to rise must be visible.

3) The air must be relatively calm.

StuRat 04:40, 9 October 2005 (UTC)

So according to number one this couldn't be dry ice? Unless I'm terribly mistaken and dry ice mixed with water is much hotter than a normal ambient air temperature. -Haon 00:01, 11 October 2005 (UTC)

I would expect dry ice mixed with water to freeze the water, no mushroom cloud there. Dry ice can create a cloud of cold vapor, which sinks instead of rising, no mushroom coud there either, unless you are talking about an upside down mushroom cloud, where it falls to the floor then spreads out. StuRat 00:09, 13 October 2005 (UTC)

Water and dry ice make a vapor (Check out Dry Ice#Uses. I just don't know if this vapor could create this effect. -Haon 12:21, 13 October 2005 (UTC)

The vapor will be colder than air, so will sink, as previously stated. The only mushroom cloud I would predict would be an upside down one, also as previously stated. StuRat 14:24, 14 October 2005 (UTC)

Q1werty

Q1werty was here--Q1werty was here 15:38, 8 October 2005 (UTC)

You might be interested in the sandbox. AlMac|^(talk) 15:43, 8 October 2005 (UTC)

L-alanine Vs. Beta-alanine

What is the difference between L-alanine and Beta-alanine?--65.33.222.71 15:45, 8 October 2005 (UTC)

The position of the amino group on the carbon chain: see alanine and beta-alanine (although the latter doesn't have a structure diagram). Physchim62 17:25, 8 October 2005 (UTC)

timber joineries and defects of timber

can you please help with informative sites on timber joineries and defects of timber

       thanking you amrita

• Amrita,

You might wish to check our Woodworking and Joinery articles for a start. Capitalistroadster 07:22, 9 October 2005 (UTC)

Gradient Invariance?

What is gradient invariance?

Invariance means 'staying the same' and a gradient can mean lots of things, but usually means a gradual change or something that can be represented with an arrow. What's the context? DirkvdM 17:31, 8 October 2005 (UTC)

I think it means that if ${\vec {A}}({\vec {r}})\,$ is vector potential of a field ${\vec {v}}({\vec {r}})\,$, then so is the ${\vec {A}}({\vec {r}})+\,$ $\mathrm {grad} \,$ $f({\vec {r}})\,$.

Compuer Science – locks and operating systems

In computer science and operating systems, what is a lock? Is it the same as a semaphore? --HappyCamper 17:45, 8 October 2005 (UTC)

No, they're slightly different. A lock (also known as a mutex) is a logical construct -- you want sole access to a resource, so you "lock" it. Locks are usually implimented using semaphores, which are operating-system-supported atomic operations (and are fairly difficult to program with) →Raul654 17:48, 8 October 2005 (UTC)

Locks are often set by application software without dependency on anything in the operating system. For example if the "in-use" field of a particular customer order is "on" that means some set of programs from one user is in middle of updating stuff in the order (which could span multiple files or tables), and all other programs in the application have to stay out until the user is completed.

Program steps

1. Is flag ok for me to access?
   1. if not, then message user about situation, and exit attempt
   2. if Ok to access, then set flag "in use" (by me)
   3. at end of access to that order, set flag "available" for others to mess with that order
2. problem ... sometimes user access breaks (Windoze gets hung, communication link times out, someone kicks wall plug), the program ends abnormally, and the flag is never reset.

AlMac|^(talk) 02:38, 9 October 2005 (UTC)

Biology: Benedicts and glucose

May I have the balanced symbol equation for the reduction of Benedict's solution by glucose, please?

Wikipedia won't do your homework for you. See Chemical equation#Balancing Chemical Equations to get started. — ceejayoz ^{★ .com} 03:31, 9 October 2005 (UTC)

Polarization of Electrons

In physics we've just been learning about the wave-particle duality of electrons and it made me wonder – can the wave 'side' of an electron be polarized like light? And if not why not, is it not a transverse wave, is particle physics just too abstract at this level for us to understand or what? ;) --BigBlueFish 19:54, 8 October 2005 (UTC)

Yes, electron beams can be polarized, and generally are in electron-positron colliders. It corresponds, if you're thinking about them as particles, to the spins all being aligned in one direction. (You can also think of polarized light as photons whose spins are aligned.) -- SCZenz 21:20, 8 October 2005 (UTC)

bees

bees can sting you. be careful. -Lethe | Talk 23:46, 8 October 2005 (UTC)

• No kidding! I got stung by one just the other day. He charged me 5 quid for a jar of honey! *boomtish*... thankyou, I'll be here all week. Try the veal! Noodhoog 14:05, 11 October 2005 (UTC)

• Our Bee article may be a good place to start. Capitalistroadster 07:25, 9 October 2005 (UTC)

A Dense Question

that hot air rises and cold air sinks. I also under stand that the same convection forces are at work in the earth and cause magma plumes to rise up to produce volcano’s. Where it all falls apart for me is that as gravity is at work on hot air in that when it cools it pulls the cold, dense air, back to the ground. How does this work in the earth when the force of gravity diminishes the closer you get to the centre?--Eye 21:40, 8 October 2005 (UTC)

That's true, there is no gravity at the center of the Earth, and therefore no buoyant force to make the magma rise. But the magma that comes out of volcanos is not from the center of the Earth, but rather from the mantle, under the crust, where there is indeed gravity and buoancy.

-Lethe | Talk 23:33, 8 October 2005 (UTC)

I think that you have a fundamental misunderstanding of gravity. Gravity does not diminish the closer you get to the center of the earth, infact, in increases very rapidly. The force of gravity is inversly proportional to the square of the distance, which mean that if you go halfway down to the center of the earth, gravity will not be not only stronger, but 4 times as strong! gkhan 00:12, 9 October 2005 (UTC)

Sorry, gkhan, but that's all wrong. It's true that the Earth is sometimes modelled as a point mass with all the mass at the center. However, this model is only accurate when you are far from the center of the Earth, and preferably at the surface or above. However, if we insisted on using that poor approximation even when we were at the center of the Earth, the calcs would give us an infinite force of gravity, since our distance from the pt mass at the center would be zero. This would cause the Earth to collapse inward on itself into a black hole, leaving only those people behind who don't insist on using the pt-mass model when it isn't applicable, LOL. An accurate model would find the gravity vector between the person at the center of the Earth and each atom in the Earth, using the distance to each atom to determine the strength. All these vectors would then be added and would total zero, if an equal number of atoms were on each side. StuRat 04:18, 9 October 2005 (UTC)

You are ofcourse right. It's been a few years, I apologise :P gkhan 10:08, 9 October 2005 (UTC)

No prob, glad to help you shake off some of the rust on your physics memory. StuRat 16:10, 9 October 2005 (UTC)

Suppose we are walking along the inside of a hollowed out asteroid that is in perfect mass balance, not spinning, The total mass under foot is tiny compared to the rest of the mass ... the center of gravity is to be floating in the middle of the hollowed out space.

But center of Earth is different matter. Gravity has crushed the material of which the Earth is made to high density near center of earth. It is not hollowed out. AlMac|^(talk) 02:44, 9 October 2005 (UTC)

It would be more correct to say the forces of gravity would be balanced at the center of the Earth, hence there is no NET gravitational force. So, indeed, a person in the center of the Earth would be weightless. However, the immense pressure from all the material is believed to make the core of the Earth solid. Only the molten mantle between the core and the crust experiences convection, and, as noted previously, there is still considerable gravity at the mantle. StuRat 04:04, 9 October 2005 (UTC)

That’s a better way of putting it …there is no net gravitational force at the centre of the earth…which I presumes means that the mass of the earth above the point of centre pulls up in all directions causing the illusion of weightlessness of any object the happens to occupy the earths centre. Mmm…anti-gravity? :-) The force of gravity must exist then, like a crust around an object with mass like the earth. The maximum pressure must be exerted from near the surface and weaken towards the middle as the increase of mass above a given point pulls up on the mass below reducing the pressure. There should then be a neutral point be where the mass above a certain point would equal the mass below. A sort of gravitational boundary layer and this point would be determined by mass not size, i.e. that point would not be equal distance from surface to centre. Would this be where the iron core begins, and if so could the iron core be colder than people expect if the pressure on it is weakened by lower gravitational forces? --Eye 19:49, 9 October 2005 (UTC)

Well, since the iron at the center is more dense, you would still expect the point of zero net gravity to be very near the geometric center of the Earth. I would also expect the iron core to be at least at hot as the material above it, since the heat has no way to dissipate, other than up through the Earth's surface. StuRat 23:58, 12 October 2005 (UTC)

Quote about solipsism involving Bertrand Russell

On the page Talk:Solipsism there is mention of a quote I've been looking for for some time. I recall quite clearly reading just a few months back about a telegram that a female logician sent to Bertrand Russell that said something very like "Have converted to solipsism. Am enjoying it immensely. Don't understand why more people don't do the same." Unfortunately, I can't find this on Google, Wikipedia, or any books I have in the house. Can anyone confirm/deny? George

I typed "betrand russell" solipsism into google and found this:

Bertrand Russell was giving a lesson on solipsism to a lay audience, and a woman got up and said she was delighted to hear Bertrand Russell say he was a solipsist; she was one too, and she wished there were more of us. - Beyond Reductionism

-- W. H. Thorpe

was that it? -Lethe | Talk 23:29, 8 October 2005 (UTC)

That's the thing. I can find references like that – to a layperson saying something dumb – but I have the clearest memory of reading about it in the joke telegram context. I do thank you for your help, though. George 00:38, 10 October 2005 (UTC)

limits in topology versus limits in category theory

Is there a way that you can interpret the limit of a sequence in a topological space as a limit of some appropriate functor between some categories? -Lethe | Talk 23:16, 8 October 2005 (UTC)

Identifying some fish and seaweed species

It would be great if someone could tell me what species some or all of the following are:

All were caught/picked off the coast of central Algeria. - Boualem 00:12, 9 October 2005 (UTC)

Genotypes

Here is the situation: A brown-eyed man whose father was brwn-eyed and mother was blue eyed married a woman whose father and mother were both brown-eyed. The couple has a blue-eyed son.

For which of the individuals mentioned can you be sure of the genotypes?

What are their genotypes? What genotypes are possible for the others?

Thank you for your time in advance

Well I'll get you started on your homework! The trait for blue eyes in humans is recessive, so any blue eyed-person must be bb in genotype. Brown-eyed people can be homozygous or heterozygous for the dominant gene B. Take it from there! Physchim62 00:41, 9 October 2005 (UTC)

What Physchim62 said is correct. For the purposes of me explaining, the brown-eyed gene shall be called B and blue-eyed gene called b. The original brown-eyed man first mentioned (who has brown-eyed father and blue-eyed mother), what would be his genotype? Well, for a brown-eyed person, it can either be Bb or BB (since B is dominant). But his mother, who is blue-eyed, must be bb is genotype since blue-eye gene is recessive. The man has to get a gene from his mother, therefore his genotype is Bb. OK, now this man marries a woman, you say. You don't tell us her genotype, but we don't need to know. This couple has a blue-eyed son. This son's genotype must be bb, as we established earlier with blue-eyed people. So this son must have got one of his b genes from the father, and one from the mother. We already know the father's genotype is Bb. So what about the mother? Well, since a b gene has to come from her, she is either Bb or bb. Even if we know that her mother and father were both brown-eyed, we still can't narrow this down further. She could still be bb, or blue-eyed, even if both parents are brown-eyed (each of her parents would be Bb). All we can say is that at least one of her parents, although we don't know who, is heterozygous for the dominant gene B. It could be either one or both of them. Hope that answers your question. -- Daverocks 13:06, 16 October 2005 (UTC)

Alcohol

Why is alcohol so fattening? ♥purplefeltangel ^(talk) ♥ ^(contribs) 03:18, 9 October 2005 (UTC)

It isn't. Non-alcoholic beer is just as fattening as alcoholic beer, for example – it is the other stuff in the drink. Lots of carbohydrates in beer. — ceejayoz ^{★ .com} 03:29, 9 October 2005 (UTC)

I might want to add a proviso to the remark above. Alcohol does have appreciable caloric content all by itself, but the total calorie content depends quite a bit on the beverage. Vodka is essentially pure alcohol (~40%) and water; it will run you about 65 calories per fluid ounce. Beer depends somewhat on how it is brewed. Stouts like Guinness get only about a quarter of their calories from carbohydrates; most of the rest is from alcohol. Sweeter lagers can draw up to about half of their calories from carbohydrates—they contain more sugar. Irish Creams like Bailey's are loaded with sugar and cream; only about a third of the calories are from alcohol, with the balance being from fat and carbohydrates. TenOfAllTrades(talk) 04:34, 9 October 2005 (UTC)

(after edit conflict)

In virtually all plants and animals, glucose is transformed into energy in three steps: glycolysis, the citric acid cycle and oxidative phosphorylation. Yeast cells produce alcohol from glucose when there is little or no oxygen: they only use glycolysis to do this, and gain much less energy as a result, only 6% of the energy released by the three steps together. When the alcohol is consumed by another animal, it is broken down by the citric acid cycle and oxidative phosphorylation: the animal which consumes the alcohol is gaining the energy which the yeast could not obtain from the sugar, ie the other 94%. Hence drinking alcoholic drinks is almost as fattening as drinking sugar solutions... Physchim62 03:37, 9 October 2005 (UTC)

Um, can you explain that in plain English please? ♥purplefeltangel ^(talk) ♥ ^(contribs) 03:43, 9 October 2005 (UTC)

Sure, the body converts alcohol into sugar, so it's just like you drank a glass full of sugar-water, which would also be fattening. StuRat 03:53, 9 October 2005 (UTC)

When turn sugar into carbon dioxide and water, you release 36 "units" of energy. When the yeast turns sugar into alcohol, it only releases 2 "units" of energy. When you drink the alcohol, your body releases the other 34 "units" that were present in the sugar. The Calories in our food are also measures of the energy released by our body when we digest the food: if we release more energy than we need, we store it as fat.... So alcohol contains almost as much energy as sugar, even if it doesn't taste sweet, and so is at least as likely to make us put on weight. Is that any better for you? Physchim62 03:51, 9 October 2005 (UTC)

Or, to put it another way. The yeast, being suck in an environment with no oxygen (by our design since we want the alcohol) relies on this trick where they can get a tiny amount of energy by doing a metabolism that results in alcohol as its end product. They do this because a little energy is better than starving to death. Later, we drink the stuff and we are able to extract the rest of the energy that the yeast was not able to get to. Since the yeast gets only about 6% of the potential, it is a good way to fatten oneself up. Qaz ^(talk) 04:00, 9 October 2005 (UTC)

Thank you. ^__^ ♥purplefeltangel ^(talk) ♥ ^(contribs) 05:08, 9 October 2005 (UTC)

I seem to remember learning in 9th grade health class that when you're drunk, your metabolism slows and converts existing stores to fat at a higher rate. This might also contribute. -Lethe | Talk 05:10, 9 October 2005 (UTC)

This is the reason I remember too, due to the liver having to process the alcohol. Dysprosia 11:29, 10 October 2005 (UTC)

I would also add a lifestyle factor. The heavier drinkers I know tend not to be the people that go jogging or to the gym. --bodnotbod 00:59, 13 October 2005 (UTC)

Tests for Lymes Disease strain idenification

I am looking for the name of a test for strain idenification to idenifty where I got Lymnes. Can you help with this test name?

Thanks, 04:52, 9 October 2005 (UTC)65.7.78.21

• Our Lyme disease articles that the two serological tests for that disease are the Western blot and the ELISA test but neither tests are reliable indicators. Polymerase chain reaction tests are used but can show false-negatives. I would speak to your doctor about tests. Capitalistroadster 07:35, 9 October 2005 (UTC)

Excel problem

I accidentally did something to my excel options (I have no idea how) and now when I press the up/down/left/right arrows on my keyboard, the view scroll as opposed to what normally happens, which is the current cell moving. Does anyone know how to change the settings back. The version is Excel 2002. Thank you :-) Akamad 04:54, 9 October 2005 (UTC)

Sounds like you have Scroll Lock turned on, IIRC. I don't have Excel handy to verify that though. — File:Ontario trillium sig.pngmendel ☎ 04:59, 9 October 2005 (UTC)

mendel is right, I just tested it out. Turn scroll lock off to fix.--inks^T 05:00, 9 October 2005 (UTC)

Thanks all. That did the trick. Akamad 05:01, 9 October 2005 (UTC)

It says something about the obsolescense of the Scroll Lock key that a person inadvertently using it for the purpose for which it was designed sees that usage as a problem. Down with Scroll Lock! Brian Schlosser42 16:45, 10 October 2005 (UTC)

Swarovski Crystal vs Teeth

Just a question. I recently bought my girlfriend a little expensive lump of Swarovski Crystal carved into the shape of a rabbit. If we get a real rabbit, put the crystal into it's cage, and the rabbit chews on the crystal, will the crystal be scratched? I'm thinking Silicates vs Calcium compounds, but have no idea of the answer. Any thoughts appreciated. :) --inks^T 05:03, 9 October 2005 (UTC)

Looking at the Mohs scale of mineral hardness we see that glass has a hardness of 6 or 7. Hydroxylapatite, the main constituent of enamel, has a hardness of 5. The rabbit, however, could break the glass with a sudden bite rather than slow scratching. --Borbrav 05:38, 9 October 2005 (UTC)

Indeed. Many people do not realize for example that although diamonds resist scratching better than any other common material, they are nonetheless vulnerable to breaking by the application of surprisingly little force. It is a good thing too or they would be much harder to cut into pleasing shapes for our Bling Bling. Qaz ^(talk) 05:42, 9 October 2005 (UTC)

Thanks guys :) --inks^T 07:43, 9 October 2005 (UTC)

general question

what is the reason for ice vessels are not licked?

Because your tongue would freeze to the side. Gdr 11:41, 9 October 2005 (UTC)

This usually only applies to materials with high themal conductivity, like metal. Materials with low themal conductivity, like styrofoam, could be very cold before licking them would freeze your tongue to them. StuRat 17:00, 9 October 2005 (UTC)

Seed Law

What is seed law?

In what context do you mean seed? Could you provide a little more information so that someone can answer you more specifically? Then again, a search for "seed law" returned a considerable number of hits, quite a few of which appear to be related to civil law in the United States. Rob Church ^{Talk | FAD} 16:06, 9 October 2005 (UTC)

Stomach acid

I read in my biology book that stomach acid is supposed to kill bacteria, then why do people get food poisoning if the acid is supposed to destroy all bacteria?

Because the bacteria can spread to all sorts of places before they even reach the stomach. - Mgm|^(talk) 11:29, 9 October 2005 (UTC)

There are several ways this can happen:

• Some kinds of food poisoning are caused by exotoxins, poisonous substances excreted by bacteria before you eat them, for example botulin produced by Clostridium botulinum.
• Some bacteria, for example Staphylococcus aureus, produce toxins in the stomach before they are killed by stomach acid; these toxins are absorbed by the intestine.
• Some other bacteria have mechanisms that allow them to survive the acidic environment of the stomach. Escherichia coli can survive for several hours at pH 2, long enough to pass through the stomach. Some Salmonella species attach themselves to food particles and thus get some protection from the acid.
• Helicobacter pylori can survive indefinitely in the stomach (causing peptic ulcers). It survives by screwing itself into the stomach wall and excreting urease, which partially neutralizes the acid in a small region surrounding the bacterium.

Gdr 11:53, 9 October 2005 (UTC)

...And not all food poisoning is bacterial (though I suppose this is a rarer case). See, for example, the cheese fly, whose maggot burrows into cheeses and preserved meats, survives stomach acids, and causes serious intestinal distress. Bunchofgrapes (talk) 22:04, 10 October 2005 (UTC)

Quotation Marks in Word

How should I force my MS Word to show “” as quot. marks instead of »« when Smart Quotes option is turned on?

Probably need to set it to English rather than French somewhere... either for the whole program, or for the text-style you're using (and don't forget: if you copy/paste anything with those quotes onto web-pages/wikipedia, then they will appear as invalid characters) Ojw 13:11, 9 October 2005 (UTC)

Whenever I switch between language keyboards I find this to be a persistent problem. For example, my main keyboard is in English, so when I start a document it does the correct "English" style smartquotes. However if at any point I switch to another language (in this case, Russian), suddenly I get only Russian smartquotes (as you have above) even after I switch back to the English keyboard. It's very irritating and I couldn't find any way around it, so I just disabled Smart Quotes completely. --Fastfission 14:48, 9 October 2005 (UTC)

I used to work in a computer lab where Word would do stuff like this often. I know there is a "Select Language" function somewhere in Word that will let you switch it back to English, but I can't recall how to access it. Try searching Word's help files for "language." Garrett Albright 15:58, 9 October 2005 (UTC)

Skin Breathing?

According to the Bond Film Goldfinger, painting someone with Gold kills them by stopping their skin breathing. Surely, if this was true, you would suffocate every time you went swimming? smurrayinchester^{(User), (Talk)} 12:52, 9 October 2005 (UTC)

On the one hand, yes, the Bond film is nonsense. On the other hand, there is a lot of oxygen suspended in water... Shimgray | talk | 13:30, 9 October 2005 (UTC)

Humans don't have gills, so this oxygen is largely useless to us. Rob Church ^{Talk | FAD} 16:07, 9 October 2005 (UTC)

If the paint were thick enough to interfere with sweating, then it might lead to hyperthermia (heat stroke). Gdr 15:26, 9 October 2005 (UTC)

• Yes, it interferes with sweating and may cause hypothermiahyperthermia, but under controlled situations it's hardly lethal as proven by the MythBusters. There's also a urban legend that the lady playing the gold-painted secretary died during filming. While it was quite uncomfortable she lived to do at least six more films and was available for a short interview with the MythBusters to show this particular legend was nonsense and she was still very much alive. - Mgm|^(talk) 17:53, 9 October 2005 (UTC)
• Snopes has a good write-up. --jpgordon∇∆∇∆ 17:54, 9 October 2005 (UTC)

The other question I have is 'If Gold is so expensive, would painting her with a pot of matte emulsion from B&Q be as effective as well as much much cheaper', but I guess he just wanted to show off. smurrayinchester^{(User), (Talk)} 20:00, 9 October 2005 (UTC)

Pucefinger just sounds wrong. And as for Brownfinger... --bodnotbod 01:04, 13 October 2005 (UTC)

How to calculate reliability

Reliability is a qualitative property, not a quantitative value, so it can't be directly calculated. What are you trying to find the reliability of? Depending upon the type of the information/source, you may need to choose from a number of methods. Rob Church ^{Talk | FAD} 16:10, 9 October 2005 (UTC)

No, there are plenty of quantitative measures of reliability (in one of its senses): see failure rate for a discussion. Gdr 16:51, 9 October 2005 (UTC)

One can use the historical reliability of a product to estimate future reliability, but this is somewhat limited by constant changes to the product line. Defects may be repaired, which may increase reliability, while new features may be added, which tend to decrease reliability.

In some cases, more direct ways to estimate the life of a product are available. For example, tires have a rated life (in km/miles) based on how quickly the rubber is expected to wear away with normal use. This type of estimate may be better for a new product, with no historical track record.

StuRat 16:54, 9 October 2005 (UTC)

Reliability of what? A measurement? In a laboratory or something like a survey? If you speak of calculation that suggests you mean something scientific. But even then there are loads of things that can be (un)reliable. DirkvdM 17:19, 9 October 2005 (UTC)

IBM hardware has a concept mean time to failure which is when they expect it to fail, on average. We had a hard disk with a mean time to failure of 13 years. When it began to get close to that old, I was trying to explain to management what that meant, without much success. Guess what? It was lucky 13 years old when we experienced a hard disk crash. AlMac|^(talk) 20:42, 10 October 2005 (UTC)

Gravitational force as caused by the electromagnetic force

A few years ago, I tried to explain gravitational force as caused by the electromagnetic force. I got a force proportional to distance to-the-power minus six (instead of the required minus two). Will the derivation be of any use in making a Unified field theory? —Masatran 14:37, 9 October 2005 (UTC)

The unification of gravity and electromagnetism has been tried before; see Kaluza-Klein theory. The results proved to be less than satisfactory, in the end, but they might be part of the solution what has turned out to be an exceedingly difficult problem. -- SCZenz 17:24, 9 October 2005 (UTC)

Converting image files

I have a Windows 98 computer. In Windows Explorer, is it possible to convert Microsoft Word files to other file types, and if so, how? HyperHobbes 15:53, 9 October 2005 (UTC)

In general, to convert files from one format to another, open them with an application which can read them (Microsoft Word, in your case), then either do a File + Save As or a File + Export and select the type of output file desired. StuRat 17:28, 9 October 2005 (UTC)

If you have a Word document, but not the program Word itself, you should still be able to open the file (then File + Save as at StuRat said) with WordPad.--Commander Keane 08:48, 10 October 2005 (UTC)

Well, this might seem silly, or impossible, but what I am trying to do is convert a Word image into a PNG. Is this possible? HyperHobbes 15:41, 13 October 2005 (UTC)

You should be able to. I don't have Microsoft Word but I was able to convert a .txt to .png with Notepad. Robmods 18:13, 13 October 2005 (UTC)

Take a screenshot, save as PNG. Ojw 17:29, 14 October 2005 (UTC)

How do I take a screenshot? HyperHobbes 16:19, 15 October 2005 (UTC)

Press the PrtSc (Print Screen) button on the keyboard to take a screenshot of the entire screen into the clipboard. Press Alt+PrtSc to take a screenshot of just the current window. You can then paste it into a program like Ms Paint, and save as a .png file. --Avi 23:15, 16 October 2005 (UTC)

• Course, Windows 98 version of MSPaint won't save as PNG unless some application has installed a plugin for PNG. XP will. SchmuckyTheCat 23:56, 18 October 2005 (UTC)

How do I enable BitTorrent in Opera 8.5?

Does Opera 8.5 have BitTorrent disabled, or is it included at all? --pile0nades^{talk | contribs} 16:46, 9 October 2005 (UTC)

The BitTorrent support was disabled on the final release of 8.5, but it's functional on the 8.10 tp2 release. See [33] ☢ Kieff | Talk 20:29, 9 October 2005 (UTC)

I already tried this one but it has ads. Is 8.10 TP2 newer than 8.5? --pile0nades^{talk | contribs} 22:07, 9 October 2005 (UTC)

No it isn't. You could always stick with 8.5 and wait until the next version of Opera, where all these features will be present. Also, the BT support in Opera wasn't so good, apparently, and it was just experimental. I think for next version you can expect something solid. Meanwhile, stick with a torrent client. ☢ Kieff | Talk 08:58, 10 October 2005 (UTC)

Get Firefox! ♥purplefeltangel ^(talk) ♥ ^(contribs) 20:59, 9 October 2005 (UTC)

Firefox doesn't support integrated BitTorrent at all, and probably won't for a long time. I'm using it now anyway though. --pile0nades^{talk | contribs} 22:07, 9 October 2005 (UTC)

Sorry, I just hate Opera. :D ♥purplefeltangel ^(talk) ♥ ^(contribs) 23:23, 9 October 2005 (UTC)

Why? Jealous? ^^ ☢ Kieff | Talk 08:55, 10 October 2005 (UTC)

Now, now boys, no fighting. We all know Firefox is better, so we shouldn't let this get ugly :P gkhan 15:59, 10 October 2005 (UTC)

Based on what you think it's better? Certainly not on security, speed, resource management, user interface, functionality and features, I'm sure. ;) ☢ Kieff | Talk 06:13, 11 October 2005 (UTC)

sending/receiving faxes online

Hi I was wondering if there was a free service or a very cheap one that would enable me to send a receive faxes online. I would prefer something that would let me goto "file" and then "print" and let me send a fax that way, similar to printing, but would ask me what phone number I would like to send it to. Something similar to efax.com. I used to use that, but now they want money.

Thanks

You can send (but not receive) for free via The Phone Company if the number you want to send to is covered by them. It works via email or their web site, not by "printing" the fax to them, but it is free. -- AJR | Talk 22:46, 9 October 2005 (UTC)

Actually, there are some clients for TPC that do act as print drivers. --WhiteDragon 18:52, 11 October 2005 (UTC)

If you just want to send a fax from your computer then all you need is a fax modem. Most of these work by having you print your document using a special print driver, then dialling another fax machine and sending just like a normal fax machine. That's not really "sending a fax online" though, as it doesn't involve the internet.. To do that you'll need some kind of web-to-fax or email-to-fax gateway service such as the one AJR named above. Typically with these kinds of services you get what you pay for.. Free ones are often limited in some way such as the amount you can send per week, or appending messages to the end of your fax. Noodhoog 14:21, 11 October 2005 (UTC)

For receiving faxes, [34] has a free account, where you get a fax number (but can't specify the area code) for a limited number of faxes that get delivered to your email inbox. --WhiteDragon 18:52, 11 October 2005 (UTC)

All the KDE applications have a "Send to fax" option in the printing menus, which I think answers the first question. Assuming you have an unused modem connected to your computer (and to a phone line), that will send the fax.

If you have a Mac, it's very similar. In the print menu, select "Fax PDF" instead of choosing a printer. To receive, tick "receive faxes on this computer" in the "Print and fax" settings window, and specify where to save them.

It should be similar for Windows, but someone else will have to tell you where the options are. Ojw 20:38, 11 October 2005 (UTC)

energy from the seatemperature

I recently heard that an average hurricane unleashes an amount of energy equal to five times the worldwide annual energy consumption of humans (still can't believe it – did I misunderstand?). I understand that that energy comes from the temperature difference between the water and the air. So naturally I thought if this energy could be harnessed. There are two obvious advantages, one being the energy source and the other being the prevention of hurricanes. The Ocean thermal energy conversion article is about temperature differences between different parts of the water, which is something different (or is it really?). Would something like this be plausible? DirkvdM 18:12, 9 October 2005 (UTC)

I've thought about this topic myself. There is a great potential there, but actually developing an efficient mechanism to exchange heat between the air and water is quite a difficult problem. The main issue is that the temp diff is so gradual and spread out over such a wide area. If we had a thousand degree temp differential of two dense fluids right next to each other, it would be easy to generate energy from this, but a 5 degree difference over two fluids (one of which is a sparse gas) more distant from each other is another matter. But, if you can think of such a device, your fortune will be made ! StuRat 20:36, 9 October 2005 (UTC)

The surface water could also be cooled by using cooler water from below the area which receives most of the thermal energy from the Sun, but this is also impractical under today's technology. Perhaps instead of waiting until the water is over-warmed, a more proactive approach is in order. Large areas of the ocean could be covered by solar collection panels, to prevent the water from becoming warm, but the low efficiency and high cost of solar cells makes this scheme impractical, too. A newer technology, like genetically engineered microbes that live in seawater tanks, extract sunlight energy by photosynthesis, and release methane gas as a waste product (which we would harness for energy). might be a better way to go. StuRat 21:08, 9 October 2005 (UTC)

Better make those microbes sterile -- I'd hate to imagine what'd happen if they were released into the real ocean and then started reproducing… Garrett Albright 18:19, 10 October 2005 (UTC)

The energy from the sun that warms the oceans is currently used to power vast ocean curents that help equalize Earth's temperatures, create hurricanes and other weather patternes, and cause vast amounts of fresh water to be distributed over the face of the earth in the form of rain and snow. The energy is not going to waste. WAS 4.250 22:27, 10 October 2005 (UTC)

There's a theory about dropping ice crystals or other chemicals from aircraft into the tropical storm from above. The crystals or other chemicals then interact with the wet air to have a chemical reaction to transfer energy to or from the storm. The idea is to try to steer it away from land. There's been experiments with this. I do not know the outcome.

There's places in the world where they get energy from the sea by tapping the tides. Consider an estuary that comes about because of a major river and how the coast to the sides of it happen to be topographically. As the tide comes in, it gets squashed sideways, so as to be quite high. Well put a dam there that drives turbines for electricity, then when the tide goes out, have the turbines going in the other direction.

Fresh water can also be got from sea water through desalination (spelling?).

There's a school of thought that if we humans do a lot of that, it could mess up the natural temperature ranges of the sea, thus impacting the ocean currents, and doing real damage. AlMac|^(talk) 06:26, 11 October 2005 (UTC)

Not sure quite how relevant this is, but there's a guy developing a system to generate power from artificial tornadoes – The Economist recently ran an article on it Noodhoog 14:30, 11 October 2005 (UTC)

GASES

HELLO JUST GOT A QUICK QUESTION ABOUT GASES, WHAT GAS DISSOLVES IN WATER AND WHY82.26.64.128 18:55, 9 October 2005 (UTC)

Lots of gases dissolve in water. Carbon Dioxide for example. But don't ask homework questions here and turn off your CAPS LOCK. smurrayinchester^{(User), (Talk)} 19:58, 9 October 2005 (UTC)

what is the SI unit used to measure time?

You'll be wanting to look at our article on SI. TenOfAllTrades(talk) 21:30, 9 October 2005 (UTC)

also Time#Present day standards --JWSchmidt 21:32, 9 October 2005 (UTC)

It will only take you a second to find the answer there. StuRat 21:38, 9 October 2005 (UTC)

Is it just me or is Mother Nature really pissed off?

• Three hurricanes went across Florida last year.
• Mt. St. Helens threatened to erupt.
• Thousands were killed by the Indian Ocean earthquake and subsequent tsunamis.
• Hurricanes Katrina and Rita tore up the Southern U.S. and areas south of that.
• A couple thousand people were killed in Guatemala due to a mudslide because of Hurricane Stan. They'll probably declare one town a mass grave since the inhabitants are under 40' of mud.
• And then there's the earthquake that hit Pakistan/India/Afghanistan with 20,000+ dead there too.
• I think I'm forgetting something from last year but I can't recall just what.

So, is it just me or does this seem like a lot of death, destruction, and mayhem caused by natural disasters for just two years? Can anyone point out another relatively short period of time where a series of events have taken place that have done similar damage? I realize that The Black Plague or possibly the devestation of Pompeii killed more but they had just one root cause. These events have had different root causes and have been more spread out. Or if I'm being naive, just let me know... :) Dismas|^(talk) 05:42, 10 October 2005 (UTC)

The exponential growth of global warming contributes to many of these disasters one way or another. --Ballchef 06:21, 10 October 2005 (UTC)

The whole global warming discussion is controversial, and I am not sure about the mechanism where is contributes to earthquakes.

Also, population pressure forces large numbers of people to live in areas subject to earthquakes, mudslides, hurricanes etc and poverty means they can't afford to build earthquake-proof buildings or flood defences. And the global media strengthens the recency illusion. You might want to see our list of disasters and the pages linked from there. Gdr 07:34, 10 October 2005 (UTC)

After edit conflict:

I don't know how many got killed in Pompei, but it can't have been too many because the population then was so much smaller than it is today that it must have been a small town by today's standards. And the death toll of the black death was immense, but the Spanish flu killed between 25 and 50 million people in one year. Which is one cause of the great death tolls. There are just more people to get killed. Another thing is that we hear more these days because the media are more present and more info on international affairs. Still, they're regionally biased. Look at your list. Out of the 9 disasters you mention 6 are in the US. Let me guess. You're from the US. Which is why those disasters get more attention than they deserve (also in Europe). Take Katrina. On a worldwide scale that was peanuts. That sort of thing happens regularly in Bangladesh.

About the overall picture, I really don't know if there have been many more disasters in the lat few years, but either the increase would have to be enormous (say ten times normal) or there would have to be a trend over a longer period to draw any statistically valid conclusion that something is going on.

Ballchef says many of these things can be attributed to global warming. In the cased of the Asia tsunami, St Helen's and the earthquakes, there's no link. But there are reports that hurricanes are becoming more frequent and occurring in places where they shouldn't occur or not at that time of year. But that's also nothing compared to the disaster we're facing with the shift in climate zones due to global warming. Crops will no longer grow where they used to. Which will lead to mass starvation. Luckily, not so much for us, more in poor countries. But it will wreck our economies as well. So we will just be less filthy rich.

In the nearer future, we can expect a pandemic of the chicken flu. That's not a question of if but of when. And it's going to be soon. With an increased population compared to the Spanish Flu it could kill more. Let's hope that the increase in technological knowledge will give us a better chance to prevent that. DirkvdM 07:48, 10 October 2005 (UTC)

Shut up you and your science!!! It's the end times coming!!!

Uhm, seriously, this was due to happen. Like it has been mentioned, global warming and super population just makes it all more tragical. Besides that, estimatives about cyclic catastrophes put this particular decade (actually, this half-century) on range of several large ones. Scientists say that soon San Francisco and Los Angeles will suffer from a massive earthquake while a bunch of volcanoes erupt worldwide, and a gas explosion happens once again on the bottom of that lake in Africa. A huge piece of earth will also collapse on that other island I forgot the name, and that will create a ultra massive tsunami. Oh, and of course, the martians arrive. Bad luck, perhaps. ☢ Kieff | Talk 08:53, 10 October 2005 (UTC)

1. An earlier generation thought AIDS was a terrible disaster.
2. A later generation will think the use of WMD by terrorists is terrible.
3. Don't forget super volcano under a major national park.
   1. and the aftermath of a giant rock from space hitting our planet ... we have the scientific know how to protect humans from what wiped out the Dinosaurs, but not the political will.
4. How come the USA is so inept when it comes to fighting wild fires out west?

   Wildfires in the western US are a normal part of the ecology there, due the dry climate and frequent lightning storms. See our wildfire article for an explanation of why trying to put them out is a bad idea. Gdr 11:58, 10 October 2005 (UTC)

5. Then there are serious consequences of the ozone hole in the Southern Hemisphere, which not get much press in the Northern.
6. Global warming and Global cooling are on a long term cycle ... consider the Vikings crossed North Atlantic Ocean at same latitude as the Titanic but had no problem with ice bergs because the Vikings were in a period of global warming, and the Titanic in a period of global cooling.
   1. Albert Gore had a book on history of environmental changes which talked about the Year of no Summer in Europe that led to an agricultural calamity that was the forerunner to the Black Death.
7. While Hurricane Katrina was a natural disaster, there was a lot of things that mankind failed to do in the mitigation of emergency planning that contributed to making the disaster much worse than it might have been otherwise.
   1. The National Hurricane Center, and other Weather Professionals have been tracking patterns for decades. They show that there are like 40-50 year cycles in frequency of tropical storms. An "inactive" cycle can still have a really bad one like Hurricane Andrew, so you always need to be prepared, especially in Florida, which seems to get more Hurricanes than the rest of the world combined. Right now we are in the early stages of an "active" cycle, meaning in the next 10 years or so they will get more frequent, which will include more of the very bad ones.
      1. The Army Corps of Engineers is using data from earlier "inactive" cycle, that says 1 chance in 500 per year, that New Orleans could be hit by a Hurricane worse than Category 3, so that's all we need to protect the city from.
      2. Millions of dollars came from the Federal government to pay to make the levees able to protect the city from a Category 3 Hurricane, but the local government found other more important things to spend that money on.
      3. Building a city below sea level seems foolish ... what's the practicality of rebuilding on higher land ... raising the land before the rebuilding
      4. Due to global warming, sea level world wide is rising slowly, so New Orleans is a precursor to what all coastal cities will be facing in the next 50 years. The vast majority of them do not have protection as "good" as New Orleans.
   2. Government knew from past Hurricanes, and US Census, that something like 1/3 of the population was too poor or disabled to voluntarily evacuate, plus there was a significant other minority that would never cooperate with a voluntary evacuation, choosing to ride out any storm because they did not understand the Category system, and also feared looters
   3. City of New Orleans had an evacuation plan, that they failed to implement
   4. Widespread Looting and Mayhem turns out to have been an Urban Legend mass produced by the News Media, that led to significant delays in getting help to New Orleans, and some ugly incidents against people trying to flee flooded areas
8. The news media has a talent for painting every humanitarian disaster as the worst ever in history, which means that a lot of people do not believe it when it really is bad.

AlMac|^(talk) 09:41, 10 October 2005 (UTC)

I don't want to put a downer on the previous upbeat answers but hang around until the next big comet impacts the Earth and wipes out 99% of life on earth. After many more big comet strikes on our planet, the Sun will eventually turn into a Red Giant and you can say goodbye to the world. That's if our solar system does't as some point get too close to a black hole and get swallowed. Actually I think that mother nature seems quite benign at the moment. Majts 09:48, 10 October 2005 (UTC)

SO... Does human population/development/existence have any effect of the frequency/size of earthwuakes, or is it all natural? --Ballchef 00:00, 11 October 2005 (UTC)

There is some speculation that the weight of oil deep down, then removed by oil drilling, can have an effect on the stability down there. AlMac|^(talk) 03:44, 11 October 2005 (UTC)

I really doubt that the tectonic plates care much about the featherweight that is human civilisation crawling on its surface.--inks^T 01:29, 11 October 2005 (UTC)

In the Netherlands we've got a problem with the ground sinking where gas has been pumped out, and that can lead to minor earthquakes. DirkvdM 17:48, 11 October 2005 (UTC)

When some part of our planet is unstable, can terrorists help trigger trouble, like perhaps setting of WMD in the side of a Volcano, letting the lava flow out there, and the change in pressure, perhaps trigger an eruption. Or is this speculation we not want to encourage? AlMac|^(talk) 03:43, 11 October 2005 (UTC)

I'm sure that would work...but if I had such a WMD I'd stick it in downtown Manhattan for greatest effect. :) --inks^T 06:05, 11 October 2005 (UTC)

This was also the theme of a James Bond film, although that's of course no guarantee that will work. But it sounded fairly plausible. DirkvdM 17:48, 11 October 2005 (UTC)

Scientologist! All you need to do is pile bodies 100-deep by a volcano, and trigger it with a nuclear weapon. Then all the dead bodies become Operating Thetans... Ojw 21:32, 15 October 2005 (UTC)

Geesh, given the diversity of all those folks (above) that are allowed to edit an encyclopedia there's no wonder about what makes this project so great. --hydnjo talk 01:19, 16 October 2005 (UTC)

Carbonic Acid

Please can anyone tell me what is the chemical mechanism for the formation of carbonic acid (H2CO3), from its constituents CO2 and H2O is? Thankyou, Ben

--163.1.209.120 07:34, 10 October 2005 (UTC)

• I'm not sure how my answer disappeared, so I'll say it again. Carbon dioxide and water form a small amount of H2CO3 when CO2 dissolves into the water. - Mgm|^(talk) 10:54, 10 October 2005 (UTC)

Under pressure (which is what soft drink maker do) more CO2 will dissolve.

Toxicity of cured epoxy

I've been sculpting with epoxy for a few weeks now and my cat just ate a tiny ball of epoxy (much less than 1 cm in diameter). The epoxy's been cured for a few days already.

I'm not sure how much of a hazard this can be to a cat. I'd suppose that cured epoxy is less dangerous (less reactive), but I don't know shit about toxicity of this substance when ingested, especially by an animal. Should I be very worried or what? ☢ Kieff | Talk 08:41, 10 October 2005 (UTC)

It says it's very toxic at the bottom of this page. Although if cured it *may* pass through the system without ingesting. Usual disclaimers: consult a vet and the epoxy packet for any warnings given. Majts 10:13, 10 October 2005 (UTC)

Actually, I just found the little ball in question behind the desk, so it's ok. :) ☢ Kieff | Talk 14:37, 10 October 2005 (UTC)

Orginal Investor In Both

Who was the orginal investor in both Microsoft and Apple Computer companies?

MANY THANKS Paul Autin, CSET Cantonment, Fl 32533-7510 [email address removed]

Please don't post your email address on the Reference Desk unless you want to receive spam. Until each company "went public," both Microsoft and Apple Computer were private companies owned by and invested in by their owners. See each respective article for more on each company's history. Garrett Albright 18:07, 10 October 2005 (UTC)

How much water would a person have to drink before it killed him?

Just curious. --Maxamegalon2000 17:32, 10 October 2005 (UTC)

The LD-50 of water is something huge – on the order of half your body-mass, I believe. Messy death, too, but very difficult to actually achieve – generally the body's reflexes kick in and stop you consuming more. It's a lot quicker by drowning! Shimgray | talk | 17:47, 10 October 2005 (UTC)

• Leah Betts supposedly died from drinking too much water, but according to that article it was more due to drinking too much water in too little time (7 litres over 1.5 hours). --Bob Mellish 17:59, 10 October 2005 (UTC)

Drinking enough to cause seizures and unconsciousness (water intoxication) is not so rare. There are plenty of case reports in the medical literature, including a few with fatal outcomes. The amount to induce unconsciousness varies by body size, ambient conditions, and starting degree of hydration, and whether alcohol or various salts or sugars were in the water, but would be much smaller than half your body mass, more like 5-10 liters of pure water chugged in rapid succession for an adult. alteripse 18:04, 10 October 2005 (UTC)

There are many factors involved. It may vary, but in a person of low blood-electrolyte concentration, the loss of necessary electrolytes can cause cellular damage, especially in the muscles and vital regions of the brain. This dilution will complicate the body's normal physiological functions, which depend on many chemicals dispersed through the body. Another may be the enormous bloating. Too much water will raise blood volume and will increase blood pressure. That can cause further problems in the cardiovascular system, making it difficult for the heart to help the blood nourish and for the blood to nourish the body.--Screwball23 15 October 2005 7:59PM

Having poked around, it seems I was remembering "enough to start physically destroying cells", as opposed to "enough to cause shock and unconsciousness, then potential death". Shimgray | talk | 18:12, 10 October 2005 (UTC)

This site says the pledge at Chico State drank 5 gallons, but there were other factors involved as well. User:Zoe|^(talk) 04:10, 13 October 2005 (UTC)

Pharmacy Compounding

Hi, I was wondering if there was a free web site that has compounding ingredients and recepies. I know there are pay sites, but they are very very expensive.

Thanks

same system call interface

Hi,

I am looking for the answer for the below question.

What are the advantages and disadvantages of using the same system call interface for manipulating both files and devices?

Thx

BK

--68.239.159.120 19:01, 10 October 2005 (UTC)

Is this question for your homework? Notinasnaid 19:10, 10 October 2005 (UTC)

Yes

You might like to note two things:

• The bit at the top of this page that says "do your own homework".
• This book by Andrew Tanenbaum. If your library has it, borrow it. --Robert Merkel 01:01, 11 October 2005 (UTC)

carat

what is the measuement called that can measure a carat that has the description of unit of weight for gemstones?

see Carat (mass). It probably answers your question . - Nunh-huh 02:56, 11 October 2005 (UTC)

Propagation speed of a tsunami wave

The propagation speed of a tsunami wave is , from what I have read , of the order of 200 to 500 km/h .

What are the factors which determine the actual speed ? Is there somewhere a description of an appropriate model which describes that wave ?

Any help will be appreciated , thank you .

There is a brief mention of the physics involved in a tsunami in our article about tsunamis (sp?).--inks^T 22:04, 10 October 2005 (UTC)

If you're a genius, look at this article and the references gkhan 22:22, 10 October 2005 (UTC)

If hazy memory of first-year physics serves, the dominant factor controlling speed of propagation of a wave is the depth of the water – shallower water slows the wave. Shimgray | talk | 22:25, 10 October 2005 (UTC)

My understanding is the same volume of water in shallower water causes the wave to go higher, so far out in deep water, the wave might only be 5 feet or so high, then when it reaches the continental shelf it can go to 100 feet high. AlMac|^(talk) 03:47, 11 October 2005 (UTC)

Frogs

Are African Clawed frogs labyrinth breathers? PLEASE HELP ME!

I've got no idea, personally, but have you looked at African clawed frog...? -- SCZenz 23:09, 10 October 2005 (UTC)

• I thought only fish were labyrinth breathers. --jpgordon∇∆∇∆ 02:35, 11 October 2005 (UTC)

Ubuntu vs Suse

I have been using Mac PCs since I was about four and Windows 9x since I was six. (I'm fourteen now.) I am now a Windows XP user. I consider myself to be fairly proficient with using computers and not screwing anything up, and recently I have been looking into installing a Linux distro on my older computer. I'm leaning heavily towards Ubuntu because I know for sure it has a GUI (which, sorry, is a requirement for a newb like me), is customizable and is, so I hear, easy for newbies. However one of my friends insists that I should get Suse, because "Ubuntu is for people who know what they're doing" and "Suse comes with more programs." I find this to be rather dubious, but I would like a final answer on this one -- should I get Ubuntu or Suse, or some other distro entirely? Thanks. ♥purplefeltangel ^(talk) ♥ ^(contribs) 21:18, 10 October 2005 (UTC)

Practically every Linux distribution designed for desktop use has a GUI, so there's no worry there. Similarly, programs tend to be available for any, since all a distribution really is in the end is a bundling-up of stuff. Nothing there to prevent someone from adding in more stuff later! Both SuSE and Ubuntu come with a great deal of stuff; since Ubuntu can use Debian packages out of the box, I think it wins in total amount of prepackaged software available. (SuSE uses RPM, like Red Hat, but they're not necessarily Red Hat compatible, while Ubuntu is explicitly Debian-compatible.) To be honest, a complete beginner won't probably notice the per-distribution differences because they are tiny compared to the differences between Linux and Windows. Both SuSE and Ubuntu offer "live CDs"; that you can boot and run without having to install anything permanently; you might try grabbing both and seeing if one or the other seems to appeal to you more. — File:Ontario trillium sig.pngmendel ☎ 23:21, 10 October 2005 (UTC)

Thank you! ♥purplefeltangel ^(talk) ♥ ^(contribs) 00:12, 11 October 2005 (UTC)

Extra question: On the Ubuntu website, where can you get LiveCDs? ♥purplefeltangel ^(talk) ♥ ^(contribs) 00:25, 11 October 2005 (UTC)

Just follow the download link, then select the release and country. For example, the page for US downloads of the Breezy Badger release candidate [35] is neatly divided into sections for install CD, live CD and combo DVD. The file you will download has a name in the form ubuntu-<version>-live-<architecture>.iso, for example ubuntu-5.10-rc-live-i386.iso.-gadfium 03:04, 11 October 2005 (UTC)

You can also have CDs posted to you for free [36]. I think everyone's waiting for the next version, due out this month. Ojw 11:46, 11 October 2005 (UTC)

I upgraded from SuSE 9 to SuSE 10 this weekend and I must say that I'm very pleased with it. SuSE 10 support all my exotic hadware such as wireless LAN, bluetooth and touchpad. However, I sometimes have problems installing software through RPM packages since they are usually build for Red Hat/Fedore, this might be better under Ubuntu since it is compatible with Debian. --R.Koot 16:02, 11 October 2005 (UTC)

New version of Ubutntu was released today. Ojw 18:53, 13 October 2005 (UTC)

Ubuntu is built on Debian. After getting comfortable with Ubuntu, try Debian itself. Debian is command-line--based and is used mainly by experts. When you want to run server software (web server, FTP server, etc.), use Debian —Masatran 07:54, 16 October 2005 (UTC)

A Sunny Question

Is there a link between the amount of matter leaving the sun and the strength of the sun's gravitional field? Like if hot air rises cold air rushes in to fill the space left behind? --Eye 21:50, 10 October 2005 (UTC)

I'll take a crack on answering this, although my knowledge of physics in the real world is somewhat limited, as noted in an above question :P. No, they are not (directly) related. The strength of the suns gravitational field is related to the sun's mass, nothing else. When you say matter leaving the sun, I am not quite certain what you mean. What leaves the sun is not matter, but light, and light is not matter (there might be particles leaving the sun in some sort of process that I am unaware of, but not enough to influence the mass of the sun in any way that matters). You mention cold and hot air, the thing is that outside the sun there is a near-perfect vacuum, so no convection occurs. gkhan 22:12, 10 October 2005 (UTC)

The solar wind is matter which leaves the Sun, but not because of convection. See the article for details. Matter also leaves the Sun by conversion into energy during nuclear fusion of hydrogen into helium. StuRat 23:05, 10 October 2005 (UTC)

Proper care after hip fracture.

I just noticed this question comes from the same address as the next, on anticoagulation, so they are probably related. One of the big risks after a hip fracture comes from prolonged immobilization – this is one reason for anticoagulation. You might want to look at the links from our hip fracture article. The answer to your question depends on the type of fracture, whether surgery has been performed or is contemplated, and to some extent on the health and age of the person with the fracture. Surgery and rehabilitation are common treatments for hip fracture. - Nunh-huh 02:55, 11 October 2005 (UTC)

How does coumdin work to thin the blood?

In short: "thinning the blood" means making it less likely to clot (it doesn't change the blood's viscosity). Coumadin, also called warfarin, does this by reducing the amount of clotting factors in the blood, by reducing the amount of certain clotting factors produced by the liver (namely, the vitamin-K dependent factors). Because it takes a few days for this reduction of clotting factor production to show up (when coumadin is taken in therapeutic doses), coumadin isn't useful in situations where blood must be "thinned" quickly: often heparin is started for short term anticoagulation and continued until coumadin's effects have been established. Our articles should tell you more, or you can ask any unanswered questions here if you like. You might also want to take a look at anticoagulant, and at antiplatelet drugs (which work to prevent clot formation, and are not blood thinners, which work by anticoagulation). - Nunh-huh 02:49, 11 October 2005 (UTC)

Are there any open source Internet Explorer shells?

I am looking for a working GPL'd IE shell, as some of its code may be useful for this Firefox plugin/extension. (current extension version is here) (also posted in Talk:Internet Explorer shell) --pile0nades^{talk | contribs} 03:24, 11 October 2005 (UTC)

I may be mistaken, but I believe all that's needed for the most basic shell is loading shdocvw.dll. It contains everything you need to make a WebBrowser control, and includes all the basic functions you'll need. --Pidgeot (t) (c) (e) 19:05, 13 October 2005 (UTC)

aiming at the bowl

Why is it hard to aim one's urine when one has a erection or semi erection? Even when one's penis is aimed at the right spot of the toilet bowl, the flow of urine doesn't hit where it should. What is causing this interference?

Warning, you may have damaged an important part of your anatomy through ignorance, and better check with a Medical Doctor for health guidance. There is a valve in there some place to control whether your penis delivers urine, or sperm. You do not want to be delivering urine to your future wife do you? You want to deliver sperm. The valve controls which is delivered, but you may have a damaged valve. (I not know the technical anatomy terminology.) AlMac|^(talk) 03:53, 11 October 2005 (UTC)

Yeowch! Be careful. There is a valve that separates to allow semen through and one that allows the urine to flow through. If you have an erection, the valve is shifted for the semen, leaving the urine valve closed for the moment. DO NOT any point try to direct your penis downward because that will NOT stop the erection and change the valve. The valve only changes when it is flaccid and it does this naturally. If you move your penis beyond a certain angle downward, or in any direction for that matter, you risk causing a penile fracture. --Screwball23 15 October 2005 8:11PM

• I'm not sure the question is relevant to your answer. Nothing's wrong with his valve (or whatever it is); he just wonders why it's hard to pee with a PHO (sometimes known as a Morning Glory). This is original research, but it seems to me that the average male penis changes in several ways when erect; I imagine the engorged portions of the penis are shaping the urethra and adjacent domains in a somewhat different way than the usual. --jpgordon∇∆∇∆ 04:48, 11 October 2005 (UTC)
  • I have some news, for you, Mister! Your aim is not so hot when you're flaccid! - Your Mom.
    • (rimshot) --jpgordon∇∆∇∆ 06:08, 11 October 2005 (UTC)
      • Thanks for the concern Almac, but I do not have a damaged valve. And Mum, I always wipe the seat when I miss. Thanks JPgordon, you seem to make sense, but what does PHO stand for?
        • Piss Hard On. I guess there isn't much need for an article on it (though if someone wanted to do an article on nocturnal erections, it could be vaguely interesting.) And Mom is sure mean. --jpgordon∇∆∇∆ 17:29, 11 October 2005 (UTC)
          • The semi-erection one could cope with, but a full? The only way I'd hit the target under such circumstances would be if the toilet were installed in the ceiling. Unless it were out of doors, in which case I would quite like the challenge of arcing it over a hedge into the given target area. Provided it were a windless day, of course. --bodnotbod 01:27, 13 October 2005 (UTC)

Sewerage into Power

I understand that researchers at Pennsylvania State University have found a way to use bacteria to generate power with sewerage. This is referenced here. As a student living on limited means in Canberra, Australia, how would I get the details of the research?

Try your local library- most public libaries in big Australian cities have subscriptions to New Sceintist.--nixie 05:15, 11 October 2005 (UTC)

God, I love how the concept of "library" outside this city I live is so utopically true. I need to leave this place, knowledge awaits. ☢ Kieff | Talk 05:24, 11 October 2005 (UTC)

• As a Canberran myself, the ACT Public Library Service would almost certainly have New Scientist and the National Library of Australia certainly would. Further, if you go to the ACT Public Library Service website with a valid library card you can use a wide variety of online services see [37]. These include Academic Search Premier database containing access to 4,650 publications including more than 3,600 peer reviewed publications and the Marshall Cavendish Science Reference Centre. Finally, if you went to either a public library or especially the National Library, a public librarian should be able to find what you want. Capitalistroadster 05:39, 11 October 2005 (UTC)

See what I mean? Damn, I'd be lucky if my library had today's local newspaper ☢ Kieff | Talk 06:09, 11 October 2005 (UTC)

Even small towns have book stores and if they not carry the magazine or whatever that interests you, they will be happy to order for you. AlMac|^(talk) 06:34, 11 October 2005 (UTC)

Yeah, we have book stores alright. But that's not how it works, not in Brazil or at least not this city. I asked a few places to get me these books ("My Inventions" by Nikola Tesla and the complete works of Edgar Allan Poe in the original english), that are published in São Paulo, but they said they couldn't do it, that I'd have to order from another city, even state. ☢ Kieff | Talk 07:42, 11 October 2005 (UTC)

Sorry, you misunderstand me. I have the particular New Scientist Magazine, but the article (like most in New Scientist) merely gives the general idea of the research. I have searched the NLA, the basic ACTLS, and have not found it. What journals would carry the detailed information?

School or university student?--Commander Keane 13:14, 11 October 2005 (UTC)

Here's the guy's webpage, and here's some links to his publications. --Robert Merkel 13:32, 11 October 2005 (UTC)

Thanks, that is very useful.

User:Kieff may wish to post a separate question here asking where there are places to order books, like amazon.com, that are happy to sell books and magazines to people in countries and cities in a relative dark ages of publishing distribution literacy. AlMac|^(talk) 20:50, 11 October 2005 (UTC)

Bah! I'd be buying online if I could afford that. For example, the aforementioned Poe book would cost 80 reais from amazon. That's raping my pocket. ☢ Kieff | Talk 12:57, 12 October 2005 (UTC)

Visibility of stars on Moon landing

Hello.Why are no stars visable on pictures or film of the moon landings.

• The Apollo moon landing hoax accusations article provides an explanation namely "There are also no stars seen in Space Shuttle, Mir, International Space Station and Earth observation photos. Cameras used for imaging these things are set for quick shutter speeds in order to prevent overexposing the film for the brightly lit daylight scenes. The dim light of the stars simply does not have a chance to expose the film. (This effect can be demonstrated on earth by taking a picture of the night sky with exposure settings for a bright sunny day. Science fiction movies and television shows do confuse this issue by depicting stars as visible in space under all lighting conditions.)" Capitalistroadster 07:27, 11 October 2005 (UTC)
  • ...which is actually a silly way of phrasing it. Of course sci fi films show stars in space, just as they ought to: stars are visible in space by th human eye. The movie experience is supposed to replicate you being there, and so replicate the vision of the human eye, not the limitations of film. That aside, Capitalistroadster is right — you don't see the stars because they're taking their exposure readings off that great big white thing. If they took a picture on the moon in which you could see the stars, the moon itself would be horribly over-exposed. — Asbestos | Talk (RFC) 16:25, 11 October 2005 (UTC)

Eyes have similar limitations, that's why we don't see stars during the day, or in brightly lit cities at night, they are drowned out by the light nearby. This is because we reduce the amount of light let into our eyes, which means the dim light from stars doesn't enter the eye in sufficient quantities to be visible. StuRat 23:11, 11 October 2005 (UTC)

information technology

what are the benefits and opportunities of information technology?

Is this, by any chance, a homework question?

Benefits of IT... like an awesome site where you have the opportunity to get smart people to help you with answers to tough questions... but not homework--Jmeden2000 14:22, 11 October 2005 (UTC)

Turn it around. What would modern business be like if there were no computers, because they had not been invented yet.

• A heck of a lot more people would have jobs that had not been automated out of business.
• Prices would be extremely high because we not have all the innovations from the computer revolution.
• Life would be much more miserable for poor people and the downtrodden around the world.
• See if you can find books about what life was like for ordinary people and for corporations like 50-75 years ago and ask how much of that was different because they did not have what we take for granted.

AlMac|^(talk) 02:05, 12 October 2005 (UTC)

citrusjuices

What is the content in apple, lemon and orange juice?

^^^^Monica

An apple isn't a citrus but in general, all fruit juices will have mostly water, a fair amount of sugar (probably mostly fructose), some flavor compounds, some flavonoids, and some vitamins usually including vitamin C. Citrus juices as the citrus article says will have a fair amount of citric acid. Our flavor article has a tiny bit of info. Ávila 15:48, 11 October 2005 (UTC)

Coin rolling

I have always wondered why is it almost impossible to balance a stationary coin on its edge, whereas if you throw it, it almost seems to want to roll it on its edge? Similarly it's virtually impossible to balance on a stationary bicycle... Shantavira 15:25, 11 October 2005 (UTC)

Have a look at gyroscope; the principles are the same. Briefly, it's all about conservation of the angular momentum of the rotating coin or bicycle wheel, but I don't want to go into more explanation than that here. TenOfAllTrades(talk) 15:31, 11 October 2005 (UTC)

Although it is easier to keep a moving coin on its smaller surface at a higher velocity, as TenOfAllTrades explained, simpler reasons are also at work. The coin is most likely more heavy on one side and has uneven friction on both the table, its surface, and probably, a minute off-level relationship with the ground and gravitational forces.

Of course, those small forces are very little compared to the conservation of angular momentum. A unicyclist will much more easily maintain balance with constant movement than a bicycle rider at a slower speed, albeit with a larger surface area.--Screwball23 15 October 2005 8:23PM

Code Coverage Standards

What are the industry standards in percentage for Code Coverage a software? &&&Surya

This is about Software testing? Ojw 20:14, 11 October 2005 (UTC)

Learning VB.Net

How easy would it be to learn Visual Basic .NET from a knowledge of Visual Basic and Java? — Asbestos | Talk (RFC) 16:03, 11 October 2005 (UTC)

I'd say that should be a good history for learning VB.NET. Syntactically, VB.NET is (of course) very similar to Visual Basic, but it uses a large built-in class library (the .NET framework), which is in some ways analogous to the Java standard libraries. VB.NET is also truly object-oriented in the same sense as Java, which is not really true of Visual Basic. Your VB and Java experience should allow you to pick up the basics of VB.NET quite easily. It will take some time, however, to gain familiarity with the ins and outs of the library, but it's pretty easy to find what you need in MSDN. —Caesura^(t) 18:24, 11 October 2005 (UTC)

Technology abuse

What types of tech abuse are there? If you can answer that would be great, I can't find any thing on Wikipedia. : ( --DB Master 16:41, 11 October 2005 (UTC)

Nuclear bombs? (Or any type of bomb for that matter.) Pretty much any technology can be abused. The question is pretty vague. DirkvdM 18:07, 11 October 2005 (UTC)

most any weapon can be abused, such as hand guns and other small arms. We can argue whether war qualifies as abuse. AlMac|^(talk) 20:55, 11 October 2005 (UTC)

We could? DirkvdM 05:03, 12 October 2005 (UTC)

electrodes to the scrotum? Majts 20:10, 11 October 2005 (UTC)

most computer users are somewhat familiar with a panorama of spam malware phishing computer viruses identity theft the list seems endless with more stuff constantly being added, and it is all tech abuse. AlMac|^(talk) 20:54, 11 October 2005 (UTC)

• The word abuse implies there are necessarily correct ways to use technology (i.e. I can only "abuse" an e-mail program if I use it in a way for which it was not intended). Tied to the question of technology abuse would be whether or not technologies have inherent purposes, and if so, to figure out how to talk about them. Is a technology's "purpose" defined by who creates it? What is the "right" way to use a technology? Controversial technologies — of which handguns are a good example — bring out this distinction well. Is there a "right" way to use a handgun? What is it? Are there "wrong" ways? What does this mean? Are all "wrong" ways "abuse"? (i.e., what if you used a handgun as a hammer, to set a nail? That would surely be against the intended use of the "gun" by the creator of it or in the minds of most people using it, but would it count as "abuse"?) --Fastfission 21:08, 11 October 2005 (UTC)

I wanted to write that! (so why didn't I?) I suppose that's what AlMac meant, that war might not be abuse of technology as long as the technology is intended for war. DirkvdM 05:03, 12 October 2005 (UTC)

I sorta meant computer wise. I shoulda put that in the question. If you could answer with the new information that would be great : )--DB Master 17:34, 12 October 2005 (UTC)

Try this DB Master. Malware look at everything. I think thats what you want. I learned what i know from that. Hope this helps Does anyone know some of the punishments for these crims? Like making "dialers, rook kits" and such. Lordned 17:43, 12 October 2005 (UTC)

The typical punishment is a few years in jail, followed by a good paying job working for some company that thinks the way to get ahead is by hiring computer abuse felons. That's the people who get caught, most do not. I think the best punishment was the guy who got millions of dollwars from computer swindling, stashed the money with a confederate while he was in jail, then when got out found that his confederate had absconded with the millions, and he was faced with the income tax authorities expecting him to pay taxes on the ill gotten gains. AlMac|^(talk) 18:49, 15 October 2005 (UTC)

Leptin

I would like to know how to increase Leptin in the the body, through diet, or any other way, naturally. I have been trying to research leptin, and only come up with sites trying to sell me some thing. Only this site, so far has provided concrete information. I would appreciate anyones comments on this.

You can raise your leptin levels by gaining body fat. Leptin is produced by adipose tissue cells and secreted into the blood. Blood levels of leptin serve as a signal to the brain and other systems in the body indicating the amount of body fat. Fat people tend to have higher leptin levels than thin people. alteripse 17:29, 11 October 2005 (UTC)

• WHy would you want to do that. Leptin appears important in regulating several processes and levels of other chemicals. Increasing your leptin levels drastically might cause things to get off-balance. - Mgm|^(talk) 22:04, 11 October 2005 (UTC)

• • I assume you are addressing our anonymous inquirer. I wondered the same thing. I might venture a guess that what he really wants to know is whether there is a way to do it without getting fatter, but I left this answer to teach him to formulate his questions more precisely. alteripse 23:37, 11 October 2005 (UTC)

• Some medical studies suggest that smoking reduces leptin levels. If you currently smoke, you can possibly increase your leptin levels by not smoking. PMID 15964536 --JWSchmidt 00:39, 16 October 2005 (UTC)

Alien water supply

In one of my biology text books, desert rats are mentioned as being able to survive without directly taking in water, at they can recieve it though metablolism (as water is one of the products of respiration), my question is, that if this is the case, why is it always strained that when searching for life on other planets, we must first search for liquid water. If the desert rat can really obtain all its water by this means than surely life on other planets could use similar means, and their dependace would only be on hydrogen, oxygen and carbon being available. Maria Knott 18:54, 11 October 2005 (UTC)

The main focus is probably on finding planets with the right environmental conditions for liquid water, not the water itself. Cells' chemical reactions take place in an aqueous solution, so if the entire planet's temperature is above the boiling point of water they would be unable to function -- not to mention that proteins would be completely denatured. Similarly, biological chemical reactions would function extremely slowly or not at all below freezing.

If life on other planets is physically and chemically similar to life on earth, it would almost certainly not survive without liquid water. However, as you pointed out, this doesn't mean that surface water is a necessity. Also, since we don't know anything about extraterrestrial life, it may not use the same chemical mechanisms as life on Earth, in which all we can do is speculate. --David Wahler (talk) 21:04, 11 October 2005 (UTC)

There would have had to have been (?) water to start with, to let the species evolve. The only way that such water-based life could be present somewhere without there being any more 'free' water is that all the life has consumed all the water. Which, on second thought, is entirely possible. But, like David says, how can we know that ET needs water? Or is carbon based (as is often assumed). We don't even know what defines life here on Earth, let alone elsewhere. The USSR once developed a robot that was meant to detect life on other heavenly bodies. When they tested it on Earth it couldn't find any life....

In a way we cannot even speak of extraterrestrial life since our definition (if one day we find it) is tied to the Earth. Well, alright, if some'thing' steps out of a machine that just came falling from the sky and says 'Hi', we're probably dealing with life (and with at least some intelligence at that). But what are the chances that it will look or behave anything like us? Just look at the variation of life here on Earth (remember animals and plants are both Eukaryotes, which is just one of the three (or so) different lifeforms here on Earth – the others are Prokaryotes, Archaea and possibly Viruses, but we don't even know if those classify as life). Then think of all the different variations of circumstances on those Googillions of different planets out there (well, most likely, anyway).

"There's life, Jim, but not as we know it" :) DirkvdM 05:44, 12 October 2005 (UTC)

Cool, thanks for replies I can impress my biology teacher! Maria Knott 05:50, 14 October 2005 (UTC)

Average cardboard container, as in What is the color of...

I'm trying to determine––in CMYK terms, if anyone knows how the color of the average cardboard box/container, as in the context of color, is arrived at; what percentages of each pigment is used for a box to achieve its 'cardboard-ness'.

If anyone has the inside dope on this, I'd be very appreciative of it being made available to/for me and/or for others. Thank you for your time.

I think most cardboard containers do not have any pigment added, so are the color of the constituent materials, such as wood pulp and the chemicals used to process it, typically resulting in a gray or brown color. StuRat 22:55, 11 October 2005 (UTC)

I took a picture of a cardboard box and sampled a pixel which I thought "average". It has RGB values of 168, 138, 104, and a hex value of #A88A68. --Borbrav 05:53, 12 October 2005 (UTC)

Well, not all cardboard has the same colour. I did that too, and came up with 193, 146, 46. But the question was what the CMYK values are. In my case that would be 0, 24, 76, 24. For your values it's 0, 18, 38, 34. DirkvdM 06:18, 12 October 2005 (UTC)

Then again, what values yo get depends very much on the exposure. First of all, the light has to be neutral, which makes a scanner a better choice than a camera, unless you use (artificial) sunlight. That would influence the balance between the colours. But the 'common level' (or what should I call that?) depends on the amount of light. Ideally, you'd scan with a just-no-overexposed exposure and then straighten the bottom end of the histogram as well. DirkvdM 06:47, 12 October 2005 (UTC)

Srinking Sun

Is the sun getting smaller. Is it burning up?--Eye 19:38, 11 October 2005 (UTC)

Strictly speaking yes. It loses 4 million tons of mass every second. Don't worry though it still has at least 4000 million years of fuel left. See the article on sun Majts 20:07, 11 October 2005 (UTC)

And mass is energy?--Eye 20:23, 11 October 2005 (UTC)

As Albert Einstein originally theorized, mass has a potential for energy E=mc², so yes. For the original bit, though, "burning up" isn't fully correct; the sun undergoes nuclear fusion rather than combustion. — Lomn | Talk / RfC 20:32, 11 October 2005 (UTC)

As Bill Clinton once said it it depends on what you mean by is? I thought the questioner meant does mass=energy? To which the answer is no – unless you multiply it by a very big number -speed of light² Majts 20:53, 11 October 2005 (UTC)

Yes I know it's just that I can't spell nukleer fishon :-)--Eye 20:46, 11 October 2005 (UTC)

No, mass is definitely not energy. In simplest terms mass is the weight of the sun. nuclear fusionis the process that scientists describe as the sun burning. This is the process that converts the mass to energy (light & heat). It's therefore a very good thing that the sun gets a miniscule amount smaller every year or we would all be very dead due to no light or heat. Majts 20:48, 11 October 2005 (UTC)

Just to correct some of the above statements: mass and energy are two different forms of the same thing. Mass and energy are interchangable at a ratio of E = M *C^2, where E is energy, M is mass, and C is the speed of light. (So a small amount of matter produces an enormous amont of energy.) However, this matter to energy conversion only takes place in nuclear reactions (that is, reactions that modify the nucleus of an atom). The only place you can find such reactions are inside stars, inside nuclear reactors, or at ground-zero of an atomic-bomb blast. Energy-to-matter conversion is possible (I think), but off the top of my head, I cannot think of any situations where it occurs. →Raul654 21:17, 11 October 2005 (UTC)

To clarify – I did not state that mass is not a form of energy (&vice versa), I just stated that mass is not energy, which is true. For example, if the questioner asked is liquid water, ice? No, ice and liquid water are forms of the same thing but they are in a different state. Thanks for making it clear though. Majts 03:36, 12 October 2005 (UTC)

Energy-to-matter conversion happens in electromagnetic cascades, such as when a cosmic ray hits the upper atmosphere. Two electrons are pair produced from a photon that interacts with a bit of atmosphere. But yes, it's quite rare, because entropy always increases.

And yes, mass is a form of energy from the modern physicist's point of view. -- SCZenz 22:38, 11 October 2005 (UTC)

I assume you meant to say an electron and a positron being formed from the cosmic ray. --Borbrav 23:05, 11 October 2005 (UTC)

I did, yes; although "electron" is often used to refer to both negative electrons and positrons, it's probably confusing if I do that here, isn't it? -- SCZenz 23:17, 11 October 2005 (UTC)

Actually, while the Sun currently is getting a tiny, tiny bit smaller every year, it will eventually balloon up into a red giant, as a natural part of its life cycle. At that stage, it will be big enough to actually swallow Mercury, Venus, and Earth. So don't feel sorry for our poor little star, and don't forget your sunblock. ;) --Ashenai (talk) 23:18, 11 October 2005 (UTC)

Quite right, the question was not if the Sun is losing mass, but if it is getting smaller. The expansion to a red giant won't take place for another 5 billion years or so. But right now the Sun is fairly stable I believe. But I haven't a clue if it's getting smaller or bigger. I suppose that depends on what you define as the boundaries. For the Earth it's fairly simple if you leave out the atmosphere. And even then it's fairly well defined. But in the case of the Sun I can imagine that the play you have in determining the boundary is much bigger than the change in size, which would mean that in as far as we can define it's size it remains the same. Then again, I don't know, really :) . DirkvdM 06:31, 12 October 2005 (UTC)

This question prompted me to write a new article for Celeritas – I couln't believe there wasn't one already Majts 00:08, 12 October 2005 (UTC)

Let me do this question again...Is the amount of the sun getting less as a result of what it's doing? :-) --Eye 19:37, 12 October 2005 (UTC)

Yes, if you mean is it losing mass. "Getting less" could also mean the volume is reducing, and there are other factors that effect that, like the temperature, so it isn't necessarily losing volume as it loses mass. StuRat 23:46, 12 October 2005 (UTC)

Estrogen and Adrenalin

What are the effects of taking or producing high levels of estrogen? What are the effects of taking or producing high levels and low levels of adrenalin?

As for the estrogen, you may want to start your research at Sex reassignment surgery and Hormone replacement therapy (trans) and go from there. Dismas|^(talk) 21:38, 11 October 2005 (UTC)

Dismas, 99.99% of people producing or taking "high levels" of estrogen around the world are females, not sex-changing males. Effects of estrogen depend on age, sex, and hormonal status of the person, how high the levels are, the duration of high levels, whether risk factors might be present that would amplify the effect, and whether a progestin is taken also. If you want something more specific, you will have to give us more to work with.

Effects of excess adrenaline depend primarily on how high, for how long, and whether the person has risk factors that would amplify effects. The most common effect of acute excess would be heart pounding, anxiety, tremor, pallor, sweating. Chronic excess occurs with pheochromocytoma and can include episodes of the acute symptoms, plus hypertension and eventually damage to heart muscle.

Effects of low adrenaline depend on whether deficiency occurs gradually or abruptly, and whether there are additional hormone deficiencies. In a healthy person, gradual loss of adrenal medullary function produces little in the way of symptoms, but for some people it can produce orthostatic hypotension in certain circumstances, or diabetic hypoglycemia in someone who takes insulin.

So what is your specific concern? (and don't tell me Dismas guessed it, or he gets to give you a more detailed answer). alteripse 23:29, 11 October 2005 (UTC)

I'm aware that the number of people taking it for sex-changes is small but the article on estrogen doesn't mention what would happen with "high levels". Although I hadn't read the articles I referenced, it would seem plausible that information about what the OP was looking for might be in the articles. Dismas|^(talk) 03:09, 12 October 2005 (UTC)

No offense intended. As you saw from my finish, I agree that you might have the opportunity to say "I told you so." However I could think of a whole lot of other contexts as well. And I had no idea what "high" was intended to mean. High relative to what? If the inquirer is sincerely interested he/she can give us more details and I will try to come up with a more precise answer. alteripse 03:23, 12 October 2005 (UTC)

No offense taken or intended on my part either. And I agree, "high" is a relative term. I took it to mean "having effects above and beyond what would be demonstrated by someone with a "normal" amount of estrogen/adrenaline in their system for their gender". It seems to smell of homework to me though. It makes me think of some high school health class concentrating on hormones in the body since I can't think off hand of how else the two would be linked. Dismas|^(talk) 04:29, 12 October 2005 (UTC)

This was not a high school question. Basically not even a board certified endocrinologist could fill in every space in the matrix I outlined without looking a few things up. Few medical students or non-endocrinologist physicians could fill half of the possibilities even given a couple of hours and a standard endocrine textbook. Give it a try and you will see what I mean.

I assume our inquirer has a specific situation in mind involving either self or a close acquaintance and with the details I might be able to better answer. alteripse 04:38, 12 October 2005 (UTC)

Invisible Spark

I am told that when we “see” a spark of electricity (or lightening) what we are seeing is electricity burning up air and/or water molecules. Is it possible to have a discharge of electricity that is invisible or does electricity always have to have a medium to travel through?--Eye 20:20, 11 October 2005 (UTC)

By "electricity", I assume you mean electrical current. Current is any flow of electrically charged particles. For example, current flowing through wires is the movement of electrons from one metal atom to the next. In the case of lightning bolts and sparks, the air's electrical resistance generates so much heat that the air molecules momentarily glow white-hot, just like in a light bulb. But a current can also flow through a cold conductor, or even a vacuum (see cathode rays), and in those cases you wouldn't see anything. --David Wahler (talk) 21:11, 11 October 2005 (UTC)

A fluorescent lamp also uses an electric current to make a gas light up, but it doesn't burn it up. DirkvdM 07:06, 12 October 2005 (UTC)

I think it's unlikely that the spark is "burning up" air or water vapour; arguably the production of ozone from oxygen could be counted as "burning oxygen" but I don't know that ozone production causes visible light. I think what you're seeing is the ionization and re-combination of oxygen and nitrogen. (And since sparks are common in dry air, I don't think water vapour is a big contributor.) Your last question is actually two unrelated questions: (a) Many discharges produce a wide range of electromagnetic wavelengths, right up into the radio spectrum, so perhaps there are contrived environments in which discharges produce no visible light; I don't really know. (b) Normally when we speak of an electrical flow we're talking about the exchange of electrons from one atom to its neighbour, whether smoothly in a conductor or chaotically in a spark; that requires a medium by definition. But an ion beam in a vacuum is also very much a flow of electricity. And induction can certainly happen through a vacuum, without even electrons passing; some would argue that it's not a "flow of elecricity" but it can certainly be part of an alternating current circuit. Sharkford 14:11, 12 October 2005 (UTC)

Losing its Shine

If the sun is losing mass, but not in the form of light because light is a massless partical, do solar eruptions and the solar wind account for all the mass being lost from the sun? --Eye 21:07, 11 October 2005 (UTC)

Also, some mass is changed into energy due to fusion of hydrogen into helium and other nuclear fusion reactions, according to Einstein's famous equation $E=mc^{2}$. StuRat 22:33, 11 October 2005 (UTC)

"Loose" is the opposite of "tight." "Lose" is the opposite of "win" (or "gain"). Now you know, and knowing is half the battle -- please tell your friends so that we can stop this abhorrent typo from perpetuating! Garrett Albright 20:05, 12 October 2005 (UTC)

vulcinism and evolution

I am very interested in volunology, and I watched both"supervolcanos"and "the Day the Earth Almost Died"(the {ermian extintion). So my quwstion is, which volcanic event-Basalt Floods(the Siberian Traps), or a supervolcanic eruption(like toba) has more of an effect on glbal climate and subsequent evolution?

The eruption that puts more ash into the atmosphere poses a greater global selection pressure on existing species. alteripse 23:34, 11 October 2005 (UTC)

Orange juice vs. apple juice

Why is it that, in a grocery store or market, orange juice is usually sold out of a cooler but apple juice (also, cranberry, grape, etc.) is generally kept on shelves? Would the orange juice spoil faster if it were on a shelf? Dismas|^(talk) 21:34, 11 October 2005 (UTC)

What country are you in? Here in NZ, all juice is equal in the eyes of the retailers, and live peacefully together on shelves. Perhaps most people just want to drink OJ now, and so it's kept cool to encourage this?--inks^T 21:39, 11 October 2005 (UTC)

Does NZ import its juice? That is probably the reason. We have dozens of varieties of OJ, with and without pulp, added calcium, added vitamins, preservatives, etc. Some are reconstituted from concentrate, many brag that they are not. I suspect the absence of preservatives and whether the product is reconstituted are the major things that determine need for refrigeration, not enticement to drink. alteripse 23:07, 11 October 2005 (UTC)

The U.S. Dismas|^(talk) 23:22, 11 October 2005 (UTC)

Store apple juice is nearly all pasteurized and has preservatives added that allow it to be kept at room temperature. You can do that with orange juice too but there is a much bigger taste difference that the folks in NZ are apparently missing. alteripse 23:32, 11 October 2005 (UTC)

Can't say I pay much attention to store layout....there is some "premium" juice that costs five times more than petrol that only lives in the coolers, and it does claim to be "preservative free", "not from concentrate" and "no added sugar"....so I'd venture that you're right with regards to preservatives and freshness :) --inks^T 23:58, 11 October 2005 (UTC)

Yeah. I'm not a picky man, but I can easily tell the difference between the stuff sold refrigerated and the stuff sold "on the shelf". (Incidentally, this was something I loved about the US – pints of good, fresh orange juice, for virtually nothing!). The real end of the scale is the stuff a housemate used to drink gallons of – the cheapest supermarket orange juice, would keep for about six months in the carton, but... ugh. Tasted like I was having heartburn. Shimgray | talk | 00:58, 12 October 2005 (UTC)

This was something I always disliked about Germany. The available juice was inferior to the refridgerated stuff in the states (the only more expensive alternative I saw was fresh squeezed offered by some restaurants), and in most homes I visited, orange juice was mixed with carbonated water. That of course didn't stop me from buying and drinking orange juice in what my neighbors clearly thought was inordinate quantities. — Laura Scudder | Talk 19:54, 12 October 2005 (UTC)

New Zealand imports most of it's orange juice- so the affordable stuff is the nasty reconstituted juice that can be kept at room temperature while unopened – fresh juice is available in most supermarkets but the price is premium. Juice from all fruits can be stored at room temperature if enough sugar, water and preservatives are added.--nixie 02:18, 12 October 2005 (UTC)

There are several ways to keep your OJ from spoiling:

• Room temperature:
  • Irradiate it: I guess people don't like it but I can live with it.
  • Boil it: These are the juices on the shelves.
  • Dry it and make it into a powder form: No. This is not for me.
• Rrefrigerator:
  • Rrefrigerate it and drink it in a matter of days: Currently the best choice in the U.S. and many other countries. (Freshly squeezed or reconstituted)
  • Add more sugar: Acceptible to some. But many people don't want their OJ sweetened.
  • Increase its acidity: Good for OJ. No good for apple juice.
• Even colder:
  • Freeze it: Add less water to the OJ concentrate. I don't know if these paper cans are available outside the U.S.

If you add much sugar or acid and boil it, any OJ can be stored on a shelf. I just don't think anyone would like to drink such thing. Pulp is also an added ingridient. To a juice factory, they can always blend in required amount of pulp to their reconstituted juice easily.

How do you like frozen OJ? These 400% juices (1 part OJ + 3 parts of water) are usually made from concentrates. -- Toytoy 04:19, 13 October 2005 (UTC)

Calculating number of days

Is there an article or website that makes it easy to calculate the number of days between two dates from different years? NoSeptember 22:10, 11 October 2005 (UTC)

Lots of them! Ther are also programs that will convert between calendars. Google for "date calculator". One is at time and date.com – Nunh-huh 22:36, 11 October 2005 (UTC)

Sum of a squared general term

if tn=n squared what does Sn equal??$Insertformulahere$

Anything you like. That's the whole point of using algebra to have the variables represent stuff. AlMac|^(talk) 02:09, 12 October 2005 (UTC)

I think the question was asking for the formula $\sum _{i=1}^{N}i^{2}={\frac {N(N+1)(2N+1)}{6}}$. To derive it, one would use the fact that the sum of an nth degree sequence is an (n+1) degree polynomial, and then proceed by mathematical induction or any of several other methods which are far nimbler but harder to explain. --Borbrav 05:41, 12 October 2005 (UTC)

Amount of work done

If there is a two-step process and two ways to go about doing it, would the way in which the first step has the bigger change in volume compared to the second, or would the way in which the second step has the bigger change in volume compared to the first, (but both arriving at the same final volume,) result in more work? Thanks
-- Миборовский ^U|T|C|E 00:15, 12 October 2005 (UTC)

In a system where there is no energy lost, the amount of work to get from one state to another should be equal, regardless of the path taken. Energy could be lost by things such as friction, however, then the energy loss would need to be investigated to determine which path would involve the most work. StuRat 02:19, 12 October 2005 (UTC)

OK, then let's say there are 2 cylinders with a piston, both having 10 L of air inside at 2 atm. Then the pressure is changed so that the volume becomes 20 L. Hess's law says same amount of work is done whether it's a multi-step reaction or single-step. But what if there are 2 kinds of multi-step reactions taking different pathways to reach the same result (volume)? Since work is not a state function, even though the end result is the same there should be some difference in work done?
-- Миборовский ^U|T|C|E 02:41, 12 October 2005 (UTC)

Exothermic reactions (which give off heat) will tend to lose energy as the heat energy will dissipate through the cylinder walls. Similarly endothermic reactions (which remove heat) tend to gain energy as the heat energy is "sucked out" of the environment. It's possible that a single reaction may generate or remove either more or less heat than two reactions, so experiment or chemistry would need to be used to determine which process has the greatest energy loss. Alternatively, you could just measure the amount of work in a more direct manner. StuRat 16:34, 12 October 2005 (UTC)

Who's this critter?

We were driving around the outskirts of Las Vegas when we noticed two of these deer (or whatever) in someone's yard. (There were also some rabbits, an emu, and heaven knows what else; it's not a native to the area, I wouldn't think.) Anyone have any idea what this is?

What sort of deer is this?

--jpgordon∇∆∇∆ 00:56, 12 October 2005 (UTC)

It looks very much like this one. Shantavira 11:22, 12 October 2005 (UTC)

It's either a Fallow deer or there is a Japanese version with a .....Japanese name.... which I can not remember --Eye 19:27, 12 October 2005 (UTC)

• I venture that you are 100% correct. Thank you very much! --jpgordon∇∆∇∆ 16:58, 13 October 2005 (UTC)

radio communications

I had a problem operating my fm receiver

It can be tuned to 3 stations only. Once i noticed that at a certain place in my house i could hear one station whereas elsewhere in the house I would hear a different station..

Howz this possible??? and that too only in that specific position in the house..?

Perhaps you need to get a new aerial? In response to the second part, perhaps you live in an area where two radio stations are broadcasting at a similar frequency, thus interfering with each other as you move around. --Ballchef 06:09, 12 October 2005 (UTC)

People near my place who live close to the radio transmission tower used to pick up radio (not sure if FM/AM) through their kettles. Do you live close to the transmission tower?--Commander Keane 14:33, 12 October 2005 (UTC)

The short wavelength of FM transmissions sometimes means that interference patterns can be set up that vary over the size of a house. If there is a radio reflector nearby (potentially anything sizeable and metal) you may get a pattern where the reflection cancels out the unreflected signal at one point, but a few metres away doesn't cancel it. DJ Clayworth 19:03, 12 October 2005 (UTC)

On the same frequency? If so, sounds like capture to me (see Frequency modulation). Dysprosia 22:42, 12 October 2005 (UTC)

Well thanx for all ur replies. 1. I dont think that broadcasting of two stations on same frequency is permitted. The station I am supposed to hear is the national broadcaster and uses same frequency all over India.

2.Well if reflections are cancelled out by a potential radio reflector around then how come I hear a different station at the same frequency.

Broadcasting two stations on the same frequency may be permitted if the two transmitters are far away enough so they don't interfere with each other. Dysprosia 09:56, 13 October 2005 (UTC)

...which is why the allocation of the spectrum is done by legislative fiat in most countries. →Raul654 10:11, 13 October 2005 (UTC)

spanning trees

How many different spanning trees does a complete graph have?- anon

See Spanning tree (mathematics). It depends on the size and amount of interlinking between the points of the graph in question. - 131.211.51.34 08:17, 12 October 2005 (UTC)

Here's an easy way to answer questions like this with a minimum of thought: work out the values for some small cases and then look up the resulting sequence in the On-Line Encyclopedia of Integer Sequences. In this case (assuming the nodes are distinguishable), graphs with 1,2,3,4 nodes have 1,1,3,16 spanning trees respectively. Look up the sequence 1,1,3,16 in the OEIS and you'll find OEIS:A000272, "Number of spanning trees in complete graph K_n on n labeled nodes", together with the formula. Gdr 18:12, 12 October 2005 (UTC)

Alkaline batteries

Why is it that certain devices(e.g. Door chimes and an electronic sphygmomanometer) will only work with alkaline batteries even though carbon/zinc batteries are the same voltage? Don Pierson--88.106.22.42 10:32, 12 October 2005 (UTC)

As a battery decharges it's voltage reduces as well. So while a carbon/zoinc and alkaline battery both deliver 1.5 volts when fully charged, a carbon/zinc battery that is half empty might only deliver 1.2 volts, while a alkaline battery that is half empty will could still produce 1.4 volts. This shouldn't affect purely electical devices as much as mechanical ones. --R.Koot 22:01, 12 October 2005 (UTC)

revolving of planets

Why do all heavenly bodies rotate? --210.214.228.78 12:36, 12 October 2005 (UTC)

Hi! You may not be aware of the fact that you actually asked two different questions. The question title says "revolving of planets", but you're asking why planets rotate. A planet's rotation and revolution are quite different things, and the reasons for them are also different. Planets revolve around the Sun: the Earth takes about 365 days to make one such revolution. They also rotate around their axis; the Earth rotates once every 24 hours. Which phenomenon are you interested in? --Ashenai (talk) 12:40, 12 October 2005 (UTC)

A star's rotation and it's planets' rotation and revolution are all a result of the rotation of the gas and dust cloud from which they formed. As they contract into smaller spheres, any small rotation is greatly magnified by the conservation of angular momentum, which means smaller objects must spin faster to have the same amount of "spin energy". Similarly, galaxies increase their spin rate from the original gas and dust clouds from which they formed, as they contract. The question then arises as to why these systems had any spin initially. Any system with nonuniformly distributed matter travelling at various relative velocities will inevitably lead to cases of rotation. (For example, imagine two stars going straight toward each other with a slight offset that capture each other to become a rotating binary star system.) But, this in turn leads to the question of why matter isn't evenly distributed in the universe. We don't know the answer to that, yet. StuRat 16:51, 12 October 2005 (UTC)

Actually, it sort of depends on what you call rotation. The Moon rotates around its axis once every evolution around the Earth. So it's always got one side turned to the Earth, so from our point of view you could say it doesn't rotate (causing the Moon to have a so-called 'dark side', which is a misnomer for the side we don't get t see from here). To my surprise, in a previous thread here I learned that this eventually happens to all heavenly bodies, so even the Earth will (given enough time) have it's rotation slowed down to once every 365 days (provided, of course, we stick to the length of a day and don't keep om defining it as one rotation of the Earth). So then one side of the Earth will be constantly facing the Sun. But then that may take longer than 5 billion years, when the Sun will consume the Earth. DirkvdM 18:41, 12 October 2005 (UTC)

This phenomenon is called Tidal lock. - Cobra Ky (talk, contribs) 23:00, 12 October 2005 (UTC)

Thames Barrier

How many times was the Thames Barrier raised in 2004?

According to the Environment Agency's page here it was closed on two occasions – the 22nd of February, and the 12th of November. Noodhoog 14:52, 12 October 2005 (UTC)

Most efficient photosynthetic organisms

Although I suspect there are variables that would impact relative efficiencies (temperature, sunlight, water quantity, etc.), is any organism more efficient than another at converting carbon dioxide to oxygen? For example, does an oak tree convert more oxygen than a comparably sized vat of bacteria or vice-versa? How would one go about comparing the efficiencies of photosynthetic organisms? 207.71.24.174 16:40, 12 October 2005 (UTC)

I would think a single-celled organism, such as algea, would be the most efficient, as it lacks the support structures of a tree like a trunk, branches, and roots. This means every cell in the organism is devoted to photosynthesis, rather than only a small portion in the case of trees. To test them both, you could place a leaf (still connected to the tree) in a sealed bag transparent to visible and UV light, and collect it after 24 hours. Measurments could then be made of the gas amounts. Similarly, an equal mass of algea (added to water) could be left in a sealed transparent container for the same amount of time and similar measurements made. This would compare the photosynthesis efficiency by wieght of a leaf to algea. If you wanted to compare the photosythesis efficiency of the entire tree, you would also need to estimate the portion of the mass of the tree which is leaves, and multiply by that. I suppose you could uproot a small tree, weigh it, then remove it's leaves, and weigh them, to figure this out. I'd hate to see a tree killed if not needed, though (I must have some Druid blood in me, LOL). StuRat 17:22, 12 October 2005 (UTC)

How fast do algae reproduce? Being small, I can imagine that may be something like one generation per day. For which you'd have to compensate in the above experiment. But the question was about bacteria, and I'm sure that with them this would be a factor to take into account. By the way, not all bacteria photosynthesise. There's a huge variation in bacteria that live under all sorts of conditions, and based on that alone it's extremely likely there's some bacterium somewhere that will outdo any plant in this respect (or any other respect for that matter). DirkvdM 18:57, 12 October 2005 (UTC)

If the mass of the remaining algea is different (from the original mass) when it is strained off from the water, then an average mass could be found between the starting and ending mass. This shouldn't technically be a linear average, (Mi+Mf)/2, since the mass would be expected to increase geometrically, not linearly, but for small changes a linear average would be a close enough approximation. StuRat 14:10, 14 October 2005 (UTC)

science

How does pressure affect time

It doesn't. Time could affect pressure, however, as in the pressure inside a room with an explosive which is detonated. The pressure would definitely change with time in such a room. StuRat 17:35, 12 October 2005 (UTC)

Actually, time and pressure are completely independent. In the explosive example, pressure varies with time (it would be equally valid to say that time varies with pressure) but neither affects the other. — Lomn | Talk / RfC 18:01, 12 October 2005 (UTC)

I suppose we are looking at the word "affect" differently, I am taking it to mean "correlates with changes in" and you are taking it to mean "causes changes in...". I suppose a correlation can be taken in either direction, but it would be far more usual to say pressure is a function on time, P(t), than to say time is function of pressure, T(p). StuRat 20:29, 12 October 2005 (UTC)

Compressing a fluid would change its stress-energy tensor, which in turn would change the Einstein tensor, which describes the curvature of spacetime. So yes, pressure can affect time. Not by much, of course, for pressures usually encountered. --Trovatore 02:16, 13 October 2005 (UTC)

How about in a Black hole? Would it be wrong to say that pressure affects time in these circumstances? Majts 18:43, 12 October 2005 (UTC)

Acceleration changes time/space in a black hole (or elsewhere, for that matter), not pressure. DirkvdM 19:03, 12 October 2005 (UTC)

Vide supra. --Trovatore 02:16, 13 October 2005 (UTC)

I agree, life is absolutely super! :) DirkvdM 08:05, 13 October 2005 (UTC)

• Pressure can have some small effects on a half life, though. --Bob Mellish 19:08, 12 October 2005 (UTC)

• Geesh, I didn't know that. I'll go have a look (always somthin' to learn around here). Thanks, --hydnjo talk 01:09, 13 October 2005 (UTC)

See weather and barometer. In Spanish (or Portuguese) the word tiempo (or tempo) translates both to time and to weather. --User:Mdob | Talk 20:23, 17 October 2005 (UTC)

how much does it pay to work as a... and how long do you have to go to college for?

I was wondering how much on average it pays to work as a volcanologist? Also how long approximately do you have to go to school to get a degree in volcanology and can you go to a community college or do you have to go to a more extensive college? Thank you

-April S.

I don't think they do it for the money. --Eye 21:22, 12 October 2005 (UTC)

If you want to work as a research scientist in *any* field, you will need to do a four-year degree, and probably a graduate degree after that (so, all up, 7 or 8 years of post-secondary education). If you can possibly afford it, at least the four-year degree is a great thing to do anyway; college broadens the mind in so many ways other than just job-related stuff. Vulcanologists are employed by either the universities or the government, so you will earn a nice living but nowhere near what, say, a doctor or stockbroker would.

Ah, but with a minor 7 year investment, you could have your very own PHD in the field of vulcanology, which would make you what? A doctor of Vulcans, sorry, couldn't help myself--Armen Schrikken 01:29, 13 October 2005 (UTC)

However, by compensation, you get all the benefits of working as a research scientist (working with interesting, smart people, solving challenging problems that nobody has before, a fair bit of travel paid for by your job), plus a few more (your travel is often to wild, beautiful place and it's easier to impress members of the opposite sex with your job than a lot of other scientific jobs ;-) ). --Robert Merkel 21:50, 12 October 2005 (UTC)

Alas those places are not just a bit wild. What percentage of vulcanologists die of natural causes? :) DirkvdM 08:04, 13 October 2005 (UTC)

Well, a volcano is natural, sort of... Shimgray | talk | 12:23, 13 October 2005 (UTC)

I do not think that the major part of vulcanologists spends a lot of time near a vulcano crater (exacltly as an astophysic do not spends most of his/her time with his/her eyes looking at a telescope ... not to cite that he/she does not spend any time on the surface of another system star :-) ). About the wage I have seen some time ago a site with the average wage of several researcher job, but I do not remeber the site at the moment. AnyFile 16:33, 15 October 2005 (UTC)

intramedullary pins

How durable are intramedullary pins, fixated in the humerus bone? Will the pin eventually break down and have to be removed? Or will it break down and cause complications to the bone?

Today's technology utilizes titanium plates and pins which will, most likely, outlast the patient. --hydnjo talk 01:01, 13 October 2005 (UTC)

Scientists

Yes, they're the finest people on Earth. ☢ Kieff | Talk 01:23, 13 October 2005 (UTC)

Matlab, DLMREAD

Yes, this is homework, but I needed help with just one line of code, if any of you are familiar with matlab. Here was the question:

%% Write a matlab function called fileToStruct that takes in a file name
%% (with extension) and returns a structure array. The file can be either a
%% .xml file or a .txt file.
%% If the file is a .xml file, it is an excel spreadsheet containing rows
%% and columns of data. You have to copy all the data from the spreadsheet
%% into a structure array. The first row in the excel file contains the
%% fieldnames of the fields of the structures. The second row onwards
%% contains data to be contained in the different structures of the
%% structure array. The value in each cell must be saved in the field
%% specified in the first row of that column. The first row (field names)
%% of the excel file contains only strings. The second row onwards can have
%% either strings or numbers. However, each column will contain only one
%% type of data (i.e. either numbers or strings). The attached figure
%% (ques1.jpg) helps explain what you have to do.
%% If the file is a .txt file, you have to do the exact same thing, except
%% that the data is in this text file and it is tab delimited.
%% Notes:
%% 1) The excel file contains only 1 sheet.
%% 2) You do not know how many rows and columns contain values
%% 3) The name and number of fields (first row) can be different for
%%    different input files.

The question I have is this:

I have a text file as shown below: (tab delimited)(each name starts a new row, but i'm not familiar with wikipedia formatting, so it should be a 4 column, 3 row matrix.

Sally     Type1  12.34  45  Yes
Joe       Type2  23.54  60  No
Bill      Type1  34.90  12  No

how do i use DLMREAD to input that data? anything i tries error outs if there's a string in the .txt file, and not just numbers. Thanks so much in advance!

I haven't read your question fully but I'll give you an example from my old lecture notes and maybe that will help. When is this thing due? If it's not due today then I will give you further help (since I'm busy using MATLAB ironically), or maybe someone else will.

Here it is:

%Code to break a line of text into tokens and store in a cell array
line= 'MATLAB is an excellent prgram yada yada';
ii=1
while any(line)
[token{ii}, line] = strtok(line);
ii=ii+1;
end

Please ask again if you need more help.--Commander Keane 01:52, 13 October 2005 (UTC)

Added <pre> tags to make the code readable --WhiteDragon 17:58, 13 October 2005 (UTC)

The effect of agriculture on soil

I know that plants use nutrients from the soil in order to grow. What I'm wondering is if the amount of nutrients is limited. Suppose a farmer— an ancient or medieval one, not a modern one— uses a given plot of land for growing crops. Do the nutrients in the soil get "used up" by the crops, to the point where it eventually won't be able to support new plants? If so, how long can a given chunk of land be used for growing crops? If not, then can a farmer use the same soil over and over again?

I realize that these are rather broad questions that could have complicated answers, but I don't need all of the details. I'm only using the information to create the history of a fantasy world in a novel I'm writing, so vague generalities are fine. —Saric (Talk) 01:14, 13 October 2005 (UTC)

There are really a lot of variables here, depleting the nutrients in the soil would vary with the type of soil, crop management practices – like crop rotation which can restore some nutrients to the soil, the type of crop grown for example legumes can grow in nitrogen poor soil which other crops could not grown in since they form symbioses which give the nitrogen, and weather conditions are just a few things to consdier. The level of technology would also affect how much people understand this, for example in some parts of Papua New Guniea they cut down a small section of rainforest, grow their crop there for a few years, then move on to a new spot since the land is not as productive after a while, whereas in places like the US a farmer would just apply fertilizers to maintain a level of productivity.--nixie 01:24, 13 October 2005 (UTC)

Another way that nutrients are replenished is through periodic flooding. Seasonal flooding deposits silt loaded with organic matter on floodplains adjacent to the river. (This process made the Nile Delta highly fertile farmland for thousands of years. Unfortunately, construction of the Aswan High Dam has ended the annual floods.) TenOfAllTrades(talk) 04:26, 13 October 2005 (UTC)

I agree and add that ancient farmers had a way to replenish the soil, too, with manure. It can add back many of the lost nutrients. StuRat 04:38, 13 October 2005 (UTC)

Other things affecting the ability of soil to sustain agriculture for long periods is exposure of the area to recent (in geologic terms) glaciation or volcanism. Qaz ^(talk) 05:33, 13 October 2005 (UTC)

This is a partial repetition of what has already been said, but it is mostly a matter of putting back in what you take out. Manure does that (ground > plant > cow-or-whatever > dung > ground). Which is also the way it works in nature (leaves falling on the ground get turned into fungus dung or something). But if you constantly grow the same crop you take out the specific nutrients that that plant needs, and manure isn't usually that specific (or is it ever?). It isn't usually natural to have a long-lasting monoculture (except on poor soils, ironically).

Tropical rainforests are different. Over time the plants (trees) have absorbed all the nutrients in the soil. Anything that falls on the ground is absorbed again before it can sink into the ground. Which is why rainforest trees don't have roots that grow deep (there's nothing there) but spread out with buttresses. So if you take the trees out you're left with almost dead soil. I suppose it might work if you left all the trees to rot and then dig the remains into the ground (and maybe let that stand for a while). But that would take years and people aren't usually that patient. DirkvdM 08:46, 13 October 2005 (UTC)

Yes, it occurred to me several years ago that beneath the feet of the rain forest lies a desert. If the rain ever stops the desert will return.

Gravity and water?

Hypothetically, if I were to fall off a 200 hundred story building strait down into a deep body of water, would I land ok? I mean water is all soft an flowy, but would it provide enough support to stop me before I hit the bottom? Is this more or less safe then jumping onto a trampoline?--Talk to the yam 02:35, 13 October 2005 (UTC)

No, you wouldn't fall ok because your body's kinetic energy wouldn't be dissipated slowly. In fact, you'd hit the water as if you were hitting concrete, because the surface tension wouldn't let your body sunk immediately and the impact would be disastrous because of the extreme deacceleration you'd experience (causing a g force peak). All this energy released on a very small period would rip your limbs off your body and pratically destroy all your inner organs! ☢ Kieff | Talk 03:13, 13 October 2005 (UTC)

You's hit the water very hard because of the surface tension of the water.--Shanedidona 03:15, 13 October 2005 (UTC)

A minor physics nitpick—you're not hitting the water hard because of its surface tension; you're hitting it hard because of the water's inertia and viscosity. When you come in contact with the liquid surface, your body rapidly displaces water down and sideways to make room for itself. Since your density is roughly equal to that of water, every kilogram of your body you immerse means a kilogram of water that has to get out of your way. If you fall from a significant height, when you hit you need to move a lot of water very quickly. That transfer of kinetic energy from your body to the surrounding water is fast and painful. TenOfAllTrades(talk) 04:17, 13 October 2005 (UTC)

It is fast and painful, but not as fast and painful as hitting granite or some other hard stone. I wonder if there are any statistics of parachutists with chutes failing to open over water?

I agree and would add that the density of the water is also critical. If you've ever done a belly flop into a pool, you know just how much water can hurt. Now multiply that by 100 and you have an idea how hitting water at those speeds would feel. StuRat 04:31, 13 October 2005 (UTC)

See also Diving#The effect of height on the dive. This claims 66 metres to be almost certainly fatal. What's that – a 22 storey building? The article doesn't dwell on the maximum speed, but terminal velocity would be reached long before 200 storeys. Unfortunately, terminal velocity may be even higher if you adopt a streamlined diving position in the hope of survival. Apparently cliff divers regularly compete at 25 metres. I suspect that with some additional accessories, like a very pointy hat and shoulder protection, higher dives could be survivable. Notinasnaid 08:09, 13 October 2005 (UTC)

Well, it of course depends on how you hit the water. If you hit it belly down a 10 m drop would already be lethal I guess. But I once heard of a guy who jumped off a burning oil platform and survived (something one isn't supposed to do when jumping of an oil pllatform :) – they can be hundreds of meters high). I don't know how he did it, but I suppose that if you fall vertically you might just break your ankles. The first meter or so won't cause too much of a water displacement, but your feet will greatly reduce your speed – maybe the guy had big feet :) . DirkvdM 08:44, 13 October 2005 (UTC)

Mythbusters ran a segment on this concept, and the general consensus was that such falls were, statistically, uniformly fatal. Of course, there's still the one-in-a-million survival without reason (just like a handful of people have apparently survived unopened parachutes). — Lomn | Talk / RfC 12:41, 13 October 2005 (UTC)

I hear that the way to survive an unopened parachute is to maximize surface area while falling to fall as slow as possible and then arrange yourself before you hit so that a few of your biggest bones break instead of a hundred smaller bones. (I seem to recall the position is curled up on your side with your head protected in your arms, which is intended to let amongst others your arms, shoulder blades and pelvis break while preserving your skull and back.) If true this would probably be the only possible way to survive a fall into water, too, but I certainly wouldn't try it. — Laura Scudder | Talk 17:38, 13 October 2005 (UTC)

This is unsourced and most likely unconfirmed, but there was a guy who fell of a bridge he was working on, and threw his hammer into the water just before he hit, thus "breaking his fall" and i think he got away with just minor injuries. I think it was true, but, you know. :) --Ballchef 13:06, 13 October 2005 (UTC)

This is the specific case from Mythbusters and it was conclusively debunked. As noted by TenOfAllTrades, surface tension is not responsible, and a hammer does not affect the viscosity of water. — Lomn | Talk / RfC 13:16, 13 October 2005 (UTC)

Ah, so that's where i saw it. thanks --Ballchef 13:30, 13 October 2005 (UTC)

The hammer does not affect the viscosity of the water, but if the hammer fell in first it might create a 'hole' in the water if the timeing were just right and then the man would fall into water that was already partly making way for him, and would have more time to slow down.

In Chester, there is a pedistrian suspension bridge notrious for breaking the spines of people who are stupid enough to dive straight off it, even though it must only be 10-15 metres above the water (well short of the 200 storey building). Some people have even died. smurrayinchester^{(User), (Talk)} 09:37, 15 October 2005 (UTC)

If the hammer were heavy enough and it would be thrown with a lot of force the reaction to this action would slow down your fall. Imagine jumping off an airplane with a big flat rock. At first you could surf through the air and then just before you reach the ground you could jump off the rock. Don't do this at home, though (if your house were big enough to fly an airplane in, that is...). Or maybe this could become the latest thrillseekers pastime. I'd hate to be responsible for that, so please don't tell anyone about this. DirkvdM 11:20, 15 October 2005 (UTC)

As to falling into water, in 1960 a boating accident above Niagara Falls caused a young boy named Roger Woodward to go over the Horseshoe Falls. This is a straight drop of just over 50 m and he is the only person to survive it without special protection such as a barrel. He was wearing a lifejacket, but that would not have helped with the impact. His terminal velocity would have been less than that of an adult, but I don't know how much, if at all, that was a factor.

As to falling out of an airplane without a parachute, you have to be lucky in what you hit. One man fell on a steep slope covered by snow. Another man fell into a pine forest, was slowed gradually by the impact of successive branches, and did not even suffer a fracture (this is Nicholas Alkemade, mentioned with less detail at the Free-fall entry).

--Anonymous, 06:45 UTC, October 16, 2005.

Prion – Alive or no?

By the definition of a prion, it almost sounds like they should be considered a living being, yet I check the definition of what constitutes an object (or anything, im not being specific) as being alive, and it doesnt meet the majority of definitions of things that make it alive. It that case, what exactly can they be called? Its like a cross between a living creature and a simple chemical reaction; i understand at the base they are similar, so which side does a prion fall on? Living or not?

• not! not even close to livuing, just a strand of catalytic protein, by that logic you should consider your prostaglandins 'alive'--Talk to the yam 02:40, 13 October 2005 (UTC)
  • As the above comment says, not even close – they are not composed of cells, they are incapable of self-replication, they do not maintain internal conditions (homeostasis), and they don't evolve. →Raul654 09:41, 13 October 2005 (UTC)
• If prions are alive then viruses are alive. ♥purplefeltangel ^(talk) ♥ ^(contribs) 02:25, 15 October 2005 (UTC)

femoral popliteal bypass surgery

Does anyone know why a person who just had femoral popliteal bypass surgery would need to elevate the leg he just had surgery on? wouldn't you want to make sure that the new bypass gets enough blood flow to the leg to ensure patency in the bypass vessel?

Thank you.

The leg elevation is suggested to avoid deep venous thrombosis, a frequent complication of many forms of therapy, by promoting venous return. That's a much higher risk than non-patency in an artery, which probably wouldn't be changed much by leg positioning. - Nunh-huh 04:22, 13 October 2005 (UTC)

Thank you, Nunh-huh. Another reason to elevate the leg is to reduce edema. now that there's a bypass, there's more blood flow to the leg, so it takes time for the leg to adjust to the new bypass vessel. Nunh-huh, i'm just wondering, do you know if there's any empirical study done about the effectiveness of keeping the leg up? or is it just one of those medical practices that's always been done?

That's actually not a different reason: the reduction in edema is equivalent to the increase in venous return. As for empirical support: It's probably a combination of habit and study – as you realize, the oldest and least technological medical habits are probably the least studied. Most new studies concentrate on newer techniques of DVT prevention. "Elastic compression stockings are useful in patients at lowest risk for thromboembolism. Intermittent pneumatic leg compression is a useful adjunct to anticoagulation and an alternative when anticoagulation is contraindicated." Am Fam Physician. 2004 Jun 15;69(12):2841-8. DVT and pulmonary embolism: Part II. Treatment and prevention. Ramzi DW, Leeper KV. md=Retrieve&db=pubmed&dopt=Abstract&list_uids=15222649&query_hl=10. You can perhaps find something about leg elevation in some of the review articles you'd find by nosing around there. - Nunh-huh 19:10, 13 October 2005 (UTC)

rearrangement of the hydrogen and oxygen atoms around the alcohol molecules

This article introduces an invention that ages cheap wines in merely seconds by a patented electrolysis process.

http://www.timesonline.co.uk/article/0,,3-1819067,00.html

Without diluting the wine, the electrolysis causes a rapid rearrangement of the hydrogen and oxygen atoms around the alcohol molecules, which would normally take place over years if the wine were ageing naturally.

What is this "rapid rearrangement" of molecules? And by the way, I cannot find any wine-related patent by the inventor Hiroshi Tanaka (田中 博) in the USPTO's patent database. Maybe I'll check Japanese patents later. -- Toytoy 03:51, 13 October 2005 (UTC)

• Laffo, ethanol doesn't have any steric centers, you can't rearrange it, that's one of the funniest things I've read all day--152.163.101.12 04:13, 13 October 2005 (UTC)

Yes, I really don't see how to rearrange the water molecules around the molecules of CH₃-CH₂-O-H. I guess Times of London goofed by trusting this patented nonsense. I just could not get first hand information by a patent search.

How does wine age? I am not a drinker. But I guess the yeast and the wooden barrels must have done something magically (good molecules added and bad ones gone). I guess you really cannot easily accelerate these taste improving chemical and physical reactions. -- Toytoy 04:30, 13 October 2005 (UTC)

I think the process (if it's not a hoax) has nothing to do with the ethanol, but rather with a great variety of other substances present in the wine. After all, wine isn't just alcohol and water, is it? You could also check this http://www.bath.ac.uk/~su3ws/wine-faq/agingwine.html out. --Borbrav 05:51, 13 October 2005 (UTC)

I suspect that the Times just got the science wrong. I can see how passing a current through wine could encourage certain chemical reactions to proceed at higher speed, producing a very rough approximation of aging. Of course, if you're not careful I can also see how this could very rapidly produce vinegar. TenOfAllTrades(talk) 13:42, 13 October 2005 (UTC)

how can I install my second computer with internet and first computer

(no content)

(moved from WP:HD) --Ballchef 05:43, 13 October 2005 (UTC)

This is a Computer networking question? Start by saying what two types of computer you have, what Operating system, and whether they have Ethernet connectors. Ojw 12:12, 13 October 2005 (UTC)

I suspect you are asking about how to install two home computers, say connected to the phone lines, so both have Internet access. It would depend on your Internet service provider, as some allow it and others do not. For those who allow it, you need to copy their software to the other computer. StuRat 15:36, 13 October 2005 (UTC)

To share internet access intended for one computer with more than one computer, you need a couple things:

1. An internet connection, obviously.
2. A local network protocol. This is almost always ethernet (over cat 5 or wireless), so make sure each computer has an ethernet card (wireless cards use 802.11a, 802.11b or 802.11g and "wired" cards are usually 10/100, though gigabit ethernet over copper is growing in popularity. Make sure that the LAN ports of all the hosts use the same protocol as the gateway. So if the hosts want wireless access, the gateway must have wireless. Otherwise all of them should have 10/100 ethernet ports.
3. Choose one interface dedicated to internet access. This means you need to either choose one of the computers to act as gateway (this computer must have two network interfaces, for example, two ethernet cards, or one ethernet card and a modem), or else you need to go out and by an internet router (this is much more popular in the US). These can be had quite cheap these days in the US. Some considerations to make before deciding:
   1. If you choose one of the computers to act as gateway, then the performance will not be as good as a dedicated router, and the connection will not work when that computer is off.
   2. If you use one of the computers as the gateway, you might have much more flexibility over the router option, depending on the operating system on the gateway, and the sophistication of the router (routers for at home use are usually not very sophisticated). You might also be able to run a server on the gateway computer, depending on your ISP's whims, which a hardware router cannot do, and computers behind a hardware router also may have problems if there is a NAT firewall (though one can get around these problems by using port forwarding or a DMZ IP address).
   3. Most (though not all) of the hardware routers for home use do not come equipped for use with modems for dial-up (because most people in the market for home networks also pony up for broadband). If you're using dialup, and your hardware router cannot hookup to a modem and doesn't have its own modem, or if you just don't have an external modem, then you have to use one of the computers as gateway.
   4. If your ISP offers only 1 IP address with its service (which almost all consumer ISPs do. For dial-up, it's impossible to offer more than 1 using the PPP protocol typical of dial-up. For broadband, most ISPs offer only 1 IP address to residential customers, though some offer extras, for more money of course) then your gateway has to run a NAT firewall. This is possible with a computer acting as gateway, or with a dedicated router.
   5. If your ISP cannot offer you a fixed IP address, as most ISPs do not, then your gateway must obtain an IP address dynamically, almost always using the DHCP protocol. All computer OSes, router software applications, and hardware routers have this capability, and almost all ISPs support it.
   6. If you're making a wireless network, decide on a wireless protocol. The newest, fastest, and widest range wireless ethernet protocol is 802.11g, but many 802.11g interfaces are backwards compatible with 802.11b only, and not with 802.11a, so if you have 802.11a hosts, you may need an 802.11a/b wireless router.
4. Once you've chosen your gateway, connect the gateway to the internet. If you're using a computer as a gateway, then you need to enable the routing, and probably also the NAT and DHCP. In Windows, this can be done by choosing "share this connection" (or something like that) after you right click the name of the connection. With a Mac, look in the sharing preference pane. Under linux, check out iptables. If you're using a hardware router, and your ISP uses dhcp, then you probably don't need to configure it at all. On the other hand, if you're doing dialup, or if your ISP doesn't use dhcp, then you need to tell your hardware router what it's doing (and hook it up to the modem if necessary).
5. Once your gateway is connected to the internet, you need to set up your local network. That means connect your second computer to the gateway (computer or router). If you're using ethernet for the local network protocol, you'll need an ethernet patch cable, unless it's wireless ethernet, in which case you won't. If you use ethernet to connect one computer to the other computer (gateway computer), then you need a crossover cat 5 ethernet patch cable, which is an ethernet cable with its wires cross. Ask for it by name. If you want more than one computer on top of your gateway, then you should buy a switch. With a switch, you do not need a crossover cable. Use a straight-through cable with the switch, this is the normal variety of ethernet cable. Many hardware routers have built-in switches. Here again, you do not need a crossover cable.
6. Once your local network is put together, you need to configure the local network hosts. This means that each computer on the LAN must know its IP address, netmask, gateway, and some DNS servers. If the gateway runs a dhcp server, then turn on dhcp in the clients, and you should be done. Else, assign the IP addresses yourself. You can pretty much choose the IP addresses to be anything you want, as long as they're all on the same network (which means that netmask AND ip address matches for each host), but you should use networks 10.x.x.x or 192,168.x.x for NAT'ed networks. The netmask is 255.0.0.0 in the first case and 255.255.255.0 in the second. The gateway IP should match the LAN IP of the gateway you chose. (Note that the gateway is configured for two networks, and so has two IPs: one from the ISP on its WAN (ethernet or dialup) interface, and one chosen by you on the local ethernet interface. The gateway IP of all hosts on the LAN should match the second IP. ) The DNS should match the DNS given to you by your ISP. Sometimes you can also give the gateway IP, as some gateways will forward DNS requests.
7. And that's it. Once you've done these steps, you should be done. It may look like a lot, but actually, in most cases, these steps are done for your automatically by the system software, so that it actually just boils down to: 1. plug WAN port of router into cable modem. 2. plug computer(s) into LAN port of router. It can be just that easy, but just in case it's not, it's nice to know all the steps, and what they mean.

Hope that helps. -Lethe | Talk 17:43, 13 October 2005 (UTC)

If you have a high-speed internet service, such as cable modem or dsl, an easier solution is to get a home router. They are self-contained units that do all this for you, so you just plug your computers into the router (they usually have a built-in ethernet switch) and the router into your cable modem or dsl. --WhiteDragon 18:06, 13 October 2005 (UTC)

Laser Printer

What are the wattage and frequency of the laser in an average laser printer?--Shanedidona 03:04, 13 October 2005 (UTC)

please ask new questions by clicking on the correct link [38], not by editing at the top of the page. By adding your question to the top of the list it is seen to be the oldest question, it may not be noticed, or archived before someone gets a chance to answer. --Ballchef 05:49, 13 October 2005 (UTC)

A quick Google search on "laser printer" and "wavelength" brings us to this page from a major manufacturer, which seems to list laser diodes for laser printers from 5 to 15 mW; most are at 790 nm. Another page of possible interest would be this one. Offhand I'd hypothesize that higher power is needed for faster printing, and higher wavelengh for higher resolution, but I'll let your further research confirm or refute that. Sharkford 18:38, 13 October 2005 (UTC)

Hamburger spoilage

Last night my wife took out a sealed pack of frozen hamburger patties. They are Wal-Mart deli burgers, and heat sealed in a plastic tray. She put them in warm water in the kitchen sink to thaw at around 5pm. However, I didn't cook them, due to unforseen circumstances. When I got up this morning to pack my lunch, lo and behold, there was the package still in the sink. I put them in the refrigerator at 7am. The question is now, are they safe to eat if cooked properly? The water was quite cool this morning, and the package is still sealed. I hate to waste food, but I hate food poisoning more...Brian Schlosser42 11:38, 13 October 2005 (UTC)

"Can it kill a brown dog?" – A good test is to see if a dog will eat it, and if so, will it survive? The colour of the dog is trivial, but brown dogs are funnier. (This was a segment from a TV show a few years back in australia, where the host would cook up some crazy mix of (often rotten) food, then feed it to his brown dog. If the dog ate it, he ate it). A foolproof test. --Ballchef 12:57, 13 October 2005 (UTC)

I don't have any dogs to experiment on, brown or otherwise. My pet roach, archy, is on vacation in the local landfill, but I wouldn't trust his judgement on what foods are good to eat. Brian Schlosser42 13:50, 13 October 2005 (UTC)

Judging from the length of time, I would say no, probably rotten. You can check it by look and smell, though. If it's gray or even worse, green or blue, toss it out. If it smells unpleasant, toss it out. If you decide to eat it, cook it thoroughly, as well-done burgers are less likely to make you sick. And don't let it languish in the fridge, as it will continue to spoil there, although at a slower rate. StuRat 15:18, 13 October 2005 (UTC)

With a larger chunk of meat, you would also have the option of cutting off the surface, with is likely to rot first, and only eating the interior. But, with individual patties, you wouldn't have much of anything left. StuRat 15:24, 13 October 2005 (UTC)

I would note that with ground meat products this practice isn't quite as effective—nasty stuff that was deposited on the surface of the freshly butchered meat gets distributed throughout the block of meat by the grinding process. (This is why you can safely eat a rare steak–the bacteria on the outside are killed during cooking–but you should cook hamburgers all the way through. Don't go poking that raw steak with a fork, either; you'll let the tasty juices out, and potentially transfer harmful bacteria into the sheltered center of the cut of meat.) TenOfAllTrades(talk) 16:38, 13 October 2005 (UTC)

Also, I suggest that if you do eat it, save it for healthy adults, as children, the elderly, and those with immune problems would be more susceptible to food poisoning. StuRat 15:30, 13 October 2005 (UTC)

So have you decided what to do with the meat yet? If you still haven't eaten it, well, you'd better throw it away. Personally I have eaten meat that has been sitting out for more than 24 hours, and I'm still alive! I do this regularly to thaw my stuff. Just cook everything very well. People are made to be scared of so many things these days. --216.191.200.1 16:18, 13 October 2005 (UTC)

I've spoken to my wife, and told her to throw it out. I'd rather be safe than sorry, to coin a phrase. Thanks for the advice, folks. Brian Schlosser42 16:33, 13 October 2005 (UTC)

I don't believe you coined that phrase. -Lethe | Talk 16:57, 13 October 2005 (UTC)

No, I didn't. I try to rectify using clichés by seasoning them with sarcasm. I started doing this one dark and stormy night...Brian Schlosser42 19:59, 13 October 2005 (UTC)

I'm sure you made the dogs that go thru your trash at night very happy, LOL. StuRat 02:59, 14 October 2005 (UTC)

Or dead. Unless they're brown. :) DirkvdM 11:33, 14 October 2005 (UTC)

No, sadly, they were tossed into the dumpster, so no brown dogs got to eat deadly meat. Oddly enough, I stopped after work and bought some replacement burgers to cook, and one of them slid off the griddle and onto the floor. Apparently I was not destined to enjoy cheeseburgers last night...Brian Schlosser42 19:35, 14 October 2005 (UTC)

One survival technique to test if you can eat something in the bush is to see if monkeys eat it. What they eat we can usually eat too. Failing that, the steps are 1) rub between your fingers 2) rub under your armpit 3) rub on your lips 4) chew a bit and spit it out. Wait for a few minutes after each step. If you feel any irritation after that don't eat it and don't continue to the next step. Then swallow a bit and wait for a day. If you don't get sick it should be safe to eat. Not that that doesn't apply here, though, just showing off some of my knowledge (which is basically the hedonistic reason I spend so much time here). DirkvdM 11:33, 14 October 2005 (UTC)

Your rubbing test is even siller that my brown dog bit. what does it do? --Ballchef 14:56, 14 October 2005 (UTC)

I'm guessing that the idea is to test progressively more sensitive areas of your body for the irritation that might indicate some sort of toxin or allergic reaction, right, DirkvdM? Brian Schlosser42 19:33, 14 October 2005 (UTC)

Right. Sorry, I was a bit too concise. DirkvdM 11:11, 15 October 2005 (UTC)

Are you going to rub a Wal-mart deli burger under your armpit?

I'm Dutch, and we don't have walmart here. So the answer would be no. But then I said I was just showing off and that it wasn't relevant to the question. DirkvdM 11:11, 15 October 2005 (UTC)

Mean reverting process

What time series analysis tools do you use to determine whether a series is mean reverting or not? --216.191.200.1 16:11, 13 October 2005 (UTC)

Macromedia Flash 8

Does anyone know any tutoorials on/about maromedia flash 8? I went to www.superflashbros.net and looked at there tutorials, but i am looking for something more detaileda bout makin the character models. Any ideas? Lord Ned

Calculating charge on suspended spheres

How do I calculate the charge of two spheres suspended on a length of material of a given length, which repel and once they reach equilibrium are separated by a distance r.

--DJK

Assuming that the two spheres are at rest, you can balance the forces on one of the spheres (see free body diagram) to find the electrostatic force. There are only three forces on each sphere, tension, a Coulomb force and gravity, and you know which direction each force is in (or can figure it out by drawing what you know about the setup). If you assume that each sphere has the same charge you can find the charge from the magnitude of the Coulomb force and the distance between the spheres. — Laura Scudder | Talk 17:26, 13 October 2005 (UTC)

Mg or Mcg ?

What is the difference between a 250 Mg tablet and a 250 Mcg tablet. I know that Mg is milligram, but what is Mcg?

--MCG is microgram. Given symbol u. (Not sure how to show it properly here). It has the value 10^-6 or 1/1,000,000.

Milligram is mg and microgram is μg (the Greek letter mu is the symbol for micro) --WhiteDragon 18:38, 13 October 2005 (UTC)

Milli is 1/1000. 10^-3

Therefore 1Mg is 1000 times bigger than 1mcg.

--DJK

You can get Greek letters this way: the code μ generates a μ. Capitalization of the letter depends on the capitalization of the code: γ and Γ generate γ and Γ, respectively.

A style note—capitalization matters in the metric (SI) system. A capital 'M' represents the prefix 'mega'–10⁶–while a lowercase 'm' represents 'milli': 10^-3. So technically 1 Mg is a million grams, or one metric tonne. (Usually the special abbreviation t is used for the tonne to avoid confusion.)

Engineers also sometimes use 'mmg' (a milli-milligram) instead of μg; fortunately this warped practice is disappearing. TenOfAllTrades(talk) 18:14, 13 October 2005 (UTC)

Mcg is a microgram which is a millionth of a gram. Mg is a milligram which is a thousanth of a gram.

First, SI unit symbols are case-sensitive, so you can't capitalize them just because you've used them at the start of a sentence. Second, the prefixes starting with the letter M are defined in SI with the following symbols:

• μ = micro = 1/1,000,000
• m = milli = 1/1,000
• M = mega = 1,000,000

It is not permitted in SI to symbolize "micro" in any other way than with the Greek letter μ. It was formerly permitted to write it u (the Latin-alphabet letter that looks most like μ) if Greek letters were not available. The form mc has never been officially permitted, but is sometimes used.

So a microgram should be written μg, but sometimes mcg is used, and ug was formerly permitted. And the equivalence is 1 mg = 1,000 μg.

Here is an excellent site on the subject of units of measurement -- where, incidentally, this question is answered right on the first page.

--Anonymous, 07:35 UTC, October 16, 2005

LISP blues

It seems that LISP interpreters I've tried so far (GCL, CLISP, and CMUCL) don't include built-in predicates for easy hardware-level or system kernel-call programming; it's possible, but it requires writing code in C and then linking it into your LISP module with a not-well-documented set of steps you have to take; and then, that ceases to make your program purely LISP/CLISP, although I am open to loading dynamic libraries. But how to load dynamic libraries common to the system, such as svgalib, seems to be even less documented in these interpreter implementations, so I'm at a stalemate here. I've fallen in love with this language this past month but I'm becoming quickly frustrated with the fact that LISP is looking more and more like a souped-up, glorified shell scripting language to me than a full-blown language that can easily do what C/C++ are capable of in terms of utilizing kernel system calls for more serious applications.

Are there any LISP/CLISP interpreters out there which allow for easier hardware-level programming and has easy-to-understand and well-versed documentation about loading dynamic libraries and everything else I need to do? Considering how old this language is I thought it might be easily done by now; any language older than C should be just as capable of OpenGL, if you know what I mean. I'm also at the point where I'm open to spending money on a proprietary LISP suite with nonstandard predicates and functions (equivalents of ioctl, etc) if I have to get these features. --I am not good at running 17:43, 13 October 2005 (UTC)

I'm pretty sure that as a native code compiler CMUCL (or its cousin SBCL) is your best bet for low-level hacking. The 'Alien Objects' and 'UNIX Interface' chapters of the CMUCL user manual should be useful. Just about all hardware and kernel-level functions are available, for example the unix-ioctl function in the unix package provides access to ioctl's. While C language libraries won't quite feel like lisp libraries, linking and calling them shouldn't be too difficult unless you are doing something wrong. Of the things you are concerned about, the only real deficiency is AFAIK access to C++ libraries, where you need to write a wrapper interface using the C++ extern "C" linkage. If you have any further questions, the cmucl-help mailing list would probably be helpful. 84.239.128.9 19:47, 13 October 2005 (UTC)

growth and development

what is the difference between growth and development?

For biological organisms, growth and development are often related aspects of how they mature and adapt to their environments; growth is often described as one aspect of development. When a distinction is to be made between the two, "growth" usually means an increase in size without fundamentally changing what it is that is growing. For example, a tumor might grow to twice its original size by cell division and cell growth. In contrast, other forms of "development" usually involve fundamental changes such as differentiation and morphogenesis. "Differentiation" meaning a significant change in the properties of a cell (changing from one cell type to another) and "morphogenesis" meaning a significant change in how a group of cells interact to form a tissue or organ. --JWSchmidt 20:40, 13 October 2005 (UTC)

Interesting. However, I usually hear that query in the context of economics. Simply put, growth is a simple increase in Gross domestic product, while development is an "improvement" in a country's overall economy. Obviously, that is a very subjective idea. Objective measurements for development include GDP per capita, the Human development index, and capital inflow, but there are many perspectives on this very complex idea. See economic growth and economic development. Superm401 | Talk 00:39, 14 October 2005 (UTC)

If you read our Economic development article it discusses development and growth as basically the same thing. As I've thought of it though, improvements in infrastructure type items, like roads, health care facilities, communications, etc are examples of development that may occur in times of contraction, not economic growth. Of course those investments as they are called in economics do contribute to GDP, but if overall GDP is falling in the short run, these investements may not contribute to growth in that short run. In general it is believed infrastructure improvements will lead to or at least remove barriers to future growth. Ávila 14:45, 14 October 2005 (UTC)

If it implies that, it's misleading people. I'll take a look at it. Superm401 | Talk 22:45, 15 October 2005 (UTC)

Quantum Time

Does time flow as a smooth linear stream or does it jump forward in tiny steps, and if it jumps in tiny steps does time stand still in between steps?

Yes no maybe ask someone else um maybe yes no. (I'm highly qualified in the field, as you can see). You might find Planck time informative; it's the "smallest meaningful unit" of time, so effectively the amount it's quantized in – nothing can happen in less than the Planck time – but I'm not sure it's really meaningful to talk about time "standing still" between steps. Shimgray | talk | 22:13, 13 October 2005 (UTC)

• Take a look at our article on time for a discussion of this. This hinges upon what time is which is a very difficult philosophical and physical question to answer. I believe the answer is, "nobody's really sure and we don't have any way to test the difference between the two at this point," though I am not an expert on this in the slightest. --Fastfission 00:38, 14 October 2005 (UTC)

Yes indeed – this is a very deep question. Certain formulations of quantum mechanics do not have quantization of time. Other more exotic species of the theory do, and of course, this includes crackpot theories and the like. The quantization which occurs in nature should not be taken too literally though – it is much more sophisticated and beautiful than what is suggested by saying that there are "jumps" in these tiny physical systems...More on that if you are interested...(and please, dig through the archives of the RD – a number of interesting quantum mechanics questions have been answered related to this topic.) --HappyCamper 00:50, 14 October 2005 (UTC)

If you want to get really confused, have a look at Zeno's arrow paradox. Here's the formulation from the philosophy pages: If motion occurs in discrete intervals, then at any given moment during its flight through the air, an arrow is not moving. But since its entire flight comprises only such moments, the arrow never moves.

About Planck time. If that is the smallest amount of time that has any meaning (to us...?) then any question about time (or whatever) in between would be meaningless. DirkvdM 11:55, 14 October 2005 (UTC)

Well, if one is going to be NPOV, one should say that any measurement of less than Planck time is meaningless. The distinction is actually quite significant to, for example, 't Hooft's attempt to resurrect hidden variable theory. --Diderot 14:08, 14 October 2005 (UTC)

I just read The Fabric of the Cosmos: Space, Time, and the Texture of Reality (ISBN 0375412883) which talked about this, you might pick it up! --Quasipalm 17:27, 14 October 2005 (UTC) BTW, the simple answer is we don't know. Please find out and report back to Wikipedia!

Exellent response Wikipeople. Thanks--Eye 19:27, 14 October 2005 (UTC)

You might also find some interesting links on the time travel article.

Many years ago I read of an experiment in which an atomic clock was taken into space on the shuttle, then when came back down, compared time to the one that had been on Earth the whole time. I forget the results of the experiment. AlMac|^(talk) 18:58, 15 October 2005 (UTC)

Sundown?

What time does the sun set? this time of year?--Egegeggegeg 22:11, 13 October 2005 (UTC)

It changes day to day. Try this website for info on your location or here. Dismas|^(talk) 22:23, 13 October 2005 (UTC)

Depends entirely where you are, so I'm afraid we can't give a meaningful answer without a location. Shimgray | talk | 22:22, 13 October 2005 (UTC)

Dry Ice

What are the properties of dry ice? How do you keep it from evaporating?

See Dry ice and for the second question, keep it frozen? Dismas|^(talk) 22:25, 13 October 2005 (UTC)

To keep the dry ice from sublimating (that's what going from a solid to a gas is called, not evaporating), keep it well insulated and place it in a freezer. A styofoam box could be used to insulate it, but a thermos would be better. Be sure the lid has vent holes in it, or is left loose, so the pressure doesn't build up and cause an explosion when it does sublimate. With luck, it might last about 3 days in the freezer. StuRat 02:44, 14 October 2005 (UTC)

I assume that a loose lid will work better than holes because it works like a valve and the build-up of CO2 gas will slow down the sublimation. I'm especially interrested if the latter is true. DirkvdM 12:38, 14 October 2005 (UTC)

The loose lid wouldn't allow pressure to build up either (that's why sodapop with a loose lid doesn't go "PFFFT" when you open it). In this case, two things are important, the total area of the opening and that no one opening is large enough for a convection cell to establish itself. That will only allow the less efficient conduction through air, which is quite slow as thermal transfer methdos go. However, you could also put a pressure relief valve in instead of a hole or loose top. That would be better, but some of those can fail in the closed position, say if water in the air freezes them shut, so sounds risky to me. StuRat 13:28, 14 October 2005 (UTC)

Also note that you won't get a convection cell, where hot gases rise because they are lighter, and cool gases fall because they are heavier, setting up a circular motion, so long as the opening is in the top of the container. Having the cool gases under the hot gases will prevent this, due to gravity. However, a thermos on it's side, with the cap missing (say if it fell over in the freezer) could very well set up a convection cell. StuRat 13:34, 14 October 2005 (UTC)

Well, a styrofoam lid would be to light for a proper pressure to build up, but if you put a weight in it it would act as a valve. DirkvdM 11:04, 15 October 2005 (UTC)

video game slowdown

Sometimes when playing a video game on an Xbox, PS2, or other console the frame rate seems to slow down when there is a lot going on in the game. What causes this slowdown? Is there any way to prevent it or make it less frequent? solaro 00:33, 14 October 2005 (UTC)

Largely lack of memory, I think. If it's a console, you can't really do much about it. Superm401 | Talk 00:43, 14 October 2005 (UTC)

If there is an option to reduce the resolution of graphics, that might allow the frame rate to speed up. Also, certain games may have ways you can play them to avoid having so much on the screen at once, and that would certainly help. StuRat 03:08, 14 October 2005 (UTC)

Home console video games almost never have options to reduce the graphics settings… that's all in the world of PC games. Anyway, what causes this is just too much data being tossed at the graphical hardware in the console for it to process in real time, so it has to take a little bit more time between frames for it to finish its work. Clearly this is undesirable, so most of the time game developers work overtime to make sure this rarely or never happens in their games, but with the super-complex games of today it's difficult to predict every single situation that may occur in a game. Sorry, there's not really a way to fix it. Garrett Albright 07:46, 14 October 2005 (UTC)

One way to limit how much is on the screen at once is to zoom in (in games with that option), so much of the action is off the screen. StuRat 13:06, 14 October 2005 (UTC)

From my experience in PC games, the problem, in 99% of times, is not in the graphics but in the sound: the program has difficulty writing to the sound buffer and everything clutters down. When I play Counter-Strike:Condition Zero, is always with the less sound quality set-up.

Run the game with no sound (or with low quality) and your problems are over. --User:Mdob | Talk 20:30, 16 October 2005 (UTC)

See our framerate article for an overview. The framerate slows down because the game is trying to do more each frame than than hardware can handle in 1/60 of a second (even if it's only taking a little longer than 1/60 second to render a frame, on games that use double buffering the framerate drops all the way to 30 Hz because the next frame won't be displayed until the next vertical synchronization). There are lots of possible bottlenecks — triangle count, rasterization cost, texture memory, sound memory, or just CPU cost. In a console game the most likely bottleneck is triangle count: you can often see this clearly because the framerate drops when the screen shows many objects. On a console there's usually nothing you can do; the developers have decided that it was worth trading lower frame rate for nicer graphics. Gdr 21:58, 16 October 2005 (UTC)

Royal Society Fellowship

I have been reading about the Royal Society, especially about John Wilkins. Can you tell me about how many fellows there were in the Society in any particular year in the very early part of the 1700's. For example, there might have been a total of deceased and living fellows of 650 in the year 1712. From David F. Grobe, 1207 Bevabeck Dr., Marion, Illinois, USA, 62959

The Royal Society have a searchable online database here although it doesn't exactly provide what you are looking for, as it only seems to be searchable via date of birth and not when they were elected. So there were 862 fellows either alive or dead in 1712 but many of those were still to be elected. They also have all of this data in 26 separate pdf files (yes, seriously!) on their web site, so you could always pull the data out of these if you have too much time on your hands and fancy some slow torture – or you could just contact the Society direct, which would be much less painful and while you're there tell them to put their data in xml format. Majts 02:11, 14 October 2005 (UTC)

meth

(moved from top of page)

Are these chemicals used in the production of meth? Someone keeps buying nasal medicine with it.

Benzalkonium Chloride, Camphor, Chlorhexidine gluconate, disodium EDTA, and tyloxapol. 208.53.200.38 01:26, 14 October 2005 (UTC)

Dear questioner,

I have no idea, but it would help you in future to read the instructions at the top of the page and click here when asking a question so that it is the newest question, not the oldest. --Ballchef 03:34, 14 October 2005 (UTC)

• Vick's Sinex, or some generic copy of it, I imagine. The camphor is sometimes used to enhance the effect of ecstasy. Look up sinex abuse on Google; there's some interesting stuff. --jpgordon∇∆∇∆ 16:39, 14 October 2005 (UTC)

Why is soapy water so slippery?

My guess is soap molecules bind weakly to both contacting surfaces and thus prevent the formation of links between two surfaces. -- Toytoy 04:02, 14 October 2005 (UTC)

Slipperiness is a general characteristic of bases. I'd guess that the excess OH^— ions attach to the exposed hydrogen atoms on the surfaces, whereas normally these sites would form hydrogen bonds between the surfaces. — Laura Scudder | Talk 04:11, 14 October 2005 (UTC)

That's a good theory because water solutions of strong bases such as NaOH can be very slippery. -- Toytoy 04:17, 14 October 2005 (UTC)

Back when I worked with NaOH on a regular basis I never felt the need to try it out, but that was mostly because of the whole burning thing with my concentrated stuff. — Laura Scudder | Talk 04:27, 14 October 2005 (UTC)

You get a soapy feeling on your fingers after having spilt sodium hydroxide solution on them because you have created a small amount of soap! The alkaline solution has hydrolysed some of the ester links in the grease on your fingers to give the sodium salts of the fatty acids, aka soap. The alkaline hydrolysis of esters is known as saponification for this reason. Physchim62 11:33, 14 October 2005 (UTC)

See above and add... The Sodium Hydroxide will also hydrolyse some of your skin as well as any grease and these molecules tend to slide over each other easily.

Soap contains the same sorts of long chain hydrocarbon molecules as do oils. I suspect that these molecules can create conditions we call "slippery" because there are only weak attractive forces acting to hold these kinds of molecules together. When soaps and other oils interact with surfaces, they "fill in the rough spots" on other materials and form lubricating molecular domains that replace otherwise high friction solid surfaces with "virtual" surfaces (hydrocarbon coatings) where the weakly interacting hydrocarbon molecules glide past eachother. --JWSchmidt 14:00, 14 October 2005 (UTC)

About pregnancy

Can swallowing cum cause pregnancy in women

• No, and it can't cause pregnancy in men either.--Pharos 06:08, 14 October 2005 (UTC)
  • Ex Africa semper aliquid novi... There's a recorded case from Johannesburg(?) in the 1980s where a woman who'd fellated her lover was discovered by her boyfriend, and in the intervening fracas stabbed; it appears the sperm was able to transit the wound before it was properly dealt with. (How she didn't get peritonitis or something I don't know). The major reason this origin was realised is because she was incapable of normal conception. (Oral conception. Impregnation via the proximal gastrointestinal tract in a patient with an aplastic distal vagina. Br J Obstet Gynaecol. 1988 Sep;95(9):933-4) Shimgray | talk | 15:33, 14 October 2005 (UTC)
• Do remember, it can cause sexually transmitted diseases if the man who's stuff you're swallowing has one, so it pays to be careful. - 131.211.51.34 07:07, 14 October 2005 (UTC)

That gives the impression that it is more risky to swallow. This isn't the case, you will have just as much chance receiving an STD if you spit. Majts 08:35, 14 October 2005 (UTC)

• However, if any cum escapes ingestion, it is still capable of causing the pregnancy you are wishing to avoid, even in very small quantities. So, be careful that any surface that has been "spoiled" does not touch anywhere near your seat of delight, and its environs -- least you "cross contaminate" to borrow a term from the world of food preparation. Qaz ^(talk) 08:19, 14 October 2005 (UTC)

I'm sure that's a myth. The seat of delight as you call it, is a hell of a long way for a sperm to travel to the overies without "direct injection". You'd have to be trying very, very hard to get your so-called cross contamination Majts 08:35, 14 October 2005 (UTC)

To be fair, I said to avoid the seat of delight (it was described thus by Realdo Colombo, one of the first to describe it for Western science) and environs. My point was that when trying to avoid a very high cost situation (allow me to employ another analogy) it is good to not just avoid hitting the target but also to stay off the firing range. Or, put another way, avoid the target and its environs. This person would take no comfort if they were to parent a child that was possible but not very probable. Qaz ^(talk) 09:08, 14 October 2005 (UTC)

And then there's the story of the woman who took a bath in a hotel room in which the previous male occupant had masturbated and consequently got pregnant (the woman, I mean :) ). If this could in principle be possible (which I doubt), then how long would the sperm survive and would any soap help in killing it? DirkvdM 12:50, 14 October 2005 (UTC)

I particularly like the quote from Realdo Colombo "the clitoris, which he called the "love or sweetness of Venus," and which he claimed to have discovered." It's just a shame he didn't leave instructions! Majts 09:37, 14 October 2005 (UTC)

• No, swallowing pretty effectively kills any risk of pregnancy. Oral sex can, however, lead to pregnancy if you use a condom. We ought to have an article on State of Louisiana v. Frisard since it's really such an odd case: A man is held liable for child support after a woman impregnates herself from sperm in a condom he used to receive a blowjob from her. But I can't find complete information about it on the web. --Diderot 10:08, 14 October 2005 (UTC)

We do have an article now State of Louisiana v. Frisard Majts 11:14, 14 October 2005 (UTC)

Something very similar happened to Boris Becker, it is called Samenraub. David Sneek 18:11, 14 October 2005 (UTC)

dogs

Do male dogs have an Adams apple?

Yes, in fact, almost every neck collar for a dog indicates that the collar should be strapped above the Adam's apple in dogs. Since dogs are mammals, they would probably exhibit similar secondary sexual features analogous to human puberty, including the development of an Adam's apple. One misconception of note is in your question; human males and females both do have Adam's apples. Males simply have ones that happen to jut outward more, making them distinguished in this feature. The pronunciation is great enough that the Adam's apple can be termed as an sex-determined or sex-inherited trait, but not one always exclusive to males.

Check Adam's apple and Oxford's entry for "Adam's apple" for more details.--Screwball23 14 October 2005 3:03PM

weird equation

if p(x) = kx^3 + (2k^2)x^2 + k^3, what is the sum of all real numbers k for which x-2 is a factor of p(x)?

Bobby

i hope this doesnt show up at the bottom again.....

Three things:

1. Questions are supposed to go to the bottom, newest at the bottom, oldest at the top :P
2. We don't solve homework-questions!
3. Even though we don't solve homework questions, I took a stab at solving it (my mathematical vein flexed, even though it hasn't been used for a while). If you want a hint, realise under what condition have to be met in order to (x-2) to be a factor of p(x). You can find that out using divison, although not the ordinary kind. gkhan 16:37, 14 October 2005 (UTC)

synthetic division perhaps?

Are you implying that people only do math when it's homework?!? I'm offended! -- Ok, not really, you're completely right. ;-) --Quasipalm 19:47, 14 October 2005 (UTC)

--Try inspection. Looks like Advanced Subsiduary level maths in the UK, type of question. Grade B probably.

DJK

what is Backint

What is the context (where did you hear this word) ? StuRat 19:54, 14 October 2005 (UTC)

health

my daughter ,13 years old ,basically T-ALL patient,on maintanence,had Toxoplsmosis infection on the pons region of brain,about 30 mm in size(MRI),resulted in impaired function of gaze,gait and speech,took medication (sulphadiazene+pyrimethamine+folinic acid)for about 42days,showed significant reducation in the size of infection,and the rescent MRI showed the size of the infection is about 11 mm in size. Though the infection has come down resonably,i have not noticed significant improvement, correspondingly, in her gaze,gait and speech.why? How long it would take for her to have normal health?

Just a guess on my part, but I would say the brain tissue which has been destroyed has not regenerated. Unfortunately, nerves do not always regenerate, but tend to do so more in children than in adults. I don't know if your daughter is too old for it to regenerate at all, or if it will just take a long time, ask your doctor about that. StuRat 19:59, 14 October 2005 (UTC)

People who suffer strokes often start off as cabbages but over time the brain rewires its self as best it can. I spent 6 weeks in hospital with a man who was brought in a total vegetable and who went out...well, nearly 100%. Not bad considering the state he was in. Remarkable thing ...the brain.

Also note that other parts of the brain may take over for the damaged part, but this may take time, speech therapy, and physical therapy to accomplish. StuRat 20:52, 14 October 2005 (UTC)

A neurologist with experience with this type of brain lesion can give you the best probabilistic answer to your question. This is as specialized a medical question as it gets, and all you get here are speculations about "if it doesnt improve this might be why". From your description I am assuming that your daughter is getting good care at a major children's hospital. If you have asked this question directly to your daughter's neurologist, you have probably gotten a much more accurate answer than we can give you here. If the answer may was unsatisfyingly vague, it is possible that her combination of conditions is too rare to provide probabilities, or that the range of probabilities is too wide to be anything but really vague. If you haven't asked the question, please do so. Good luck. alteripse 21:21, 14 October 2005 (UTC)

What age do most homosexuals discover their identity?

I hear differing ranges on this question, but I am interested by the number of people who discover their true sexual identities later and later in life, sometimes after being married and having children. This contrasts greatly with the adolescent/young adult psychosexual development model I had been taught. What is the exact age that most find out the truth about themselves, particularly in American society?

According to a recent story in Time Magazine, the average age has dropped into the teens. →Raul654 18:35, 14 October 2005 (UTC)

Middle-aged people who "discover" they are homosexual probably really knew so all along, on some level, but just kept it secret, perhaps even from themselves. Those who actually had no attraction to their own sex and then changed sexual orientations spontaneously in mid-life would be truly rare, and worthy of study, if they exist. I would suggest that some physical change has occured in the brain in such cases; perhaps a virus or some other disease has changed the nueral pathways. The same comment would be true of a homosexual who suddenly become a heterosexual in mid-life. StuRat 19:46, 14 October 2005 (UTC)

Anecdotal evidence to support this: a nominally bisexual acquaintance of mine told me once that she was attracted to other girls from early childhood, indeed long before she was aware of what homosexuality was. My belief is that many gays and lesbians know what they are from a very, very early age. Of course, I also believe that sexual orientation is not (for the most part) a choice, but a genetic issue, so I may be prejudiced.Brian Schlosser42 19:52, 14 October 2005 (UTC)

Another explanation is that they were bisexuals who just switched behaviours, but are still attracted to both genders, as before. StuRat 19:50, 14 October 2005 (UTC)

And yet another view. Notice how your question implies a couple of assumptions that represent current conventional wisdom but may be more culturally shaped than you think. Your first assumption is that homosexuality is a lifelong biological condition like a blood-type which is always there but gets discovered and recognized as the "true self" at some point in time, sort of like finding out what your blood type is. Your second is that this is the "true" identity, and conversely their earlier identities and behaviors were therefore "false". This is the "essentialist" (born that way) position and has not always been a universally accepted way to think about homosexuality. Another way to look at it is more complex, and involves distinguishing concepts like (a) self-identified cultural roles from (b) degree of attraction to potential partners of a specific sex, and (c) recognizing that cultural and other environmental factors may influence the response to such feelings, and (d) the interpretation made by the person and those around him/her. This distinction may be especially applicable as a way to think about adult changes of preferred sexual partner. In an oversimplified nutshell, this is the distinction between "homosexuality is what someone is" and "homosexuality is what someone does". The essentialist/constructionist debate is not consistently "mappable" to liberal or conservative politiics: 30 years ago, the idea that there were biological factors strongly determining a homosexual identity was anathema to the gay left and politically correct academics. Now the fashion has swung the other way, but history suggests it will change again, and many people are skeptical that there will be a simple biological "born that way" explanation discovered.

This is a controversial topic and the average age of wikipedia contributors ensures that most will not know how vehemently people from 30 years ago of the same age, same education, same politics, and same gay-supportive attitudes would disagree with them over this. alteripse 21:09, 14 October 2005 (UTC)

I am convinced that "sexuality" lies on a spectrum. And as in the colors of a spectrum there is no dividing line but rather a gradual merging from one color to another. And such is sexuality. Society on the other hand has no patience for this kind of explanation preferring instead to have tidy little boxes and labels. This lack of patience for reality does in fact result in premature self-identification into one of the boxes along with its self-perpetuating requirements, obligations and predjudices. --hydnjo talk 23:35, 14 October 2005 (UTC)

A certain feminist theory (not that i particularly agree with it) reckons that sexual preferences can be learned, thus making the age at whenever one begins practicing homosexuality. A prominent fem-activist (i forget her name) said she learnt to be a lesbian, which she felt she had to do because otherwise she wasn't really a feminist. This was when she was in her thirties or thereabouts after living a previously straight lifestyle. --Ballchef 01:00, 15 October 2005 (UTC)

Which is exactly what I'm talking about. Being put into a set of expectations, regardless of feelings, until maturity catches up (if ever) and one faces their own place on the spectrum of sexuality. --hydnjo talk 01:25, 15 October 2005 (UTC)

As the responses so far show, this isn't an easy question to answer. I've met gay men who say that they've always known they were gay, but until their teens they didn't know that there was a word for it or that it had to do with sex. And, I've met gay men who say that they "realised" they were gay far later in life after a series of unsuccessful relationships with women.

You might look for an answer by turning the question around: When did you realise that you were straight? Is there any simple answer to that question?

I'm one of the people who think that there is probably no simple biological cause for homosexuality – I don't think it's hereditary or a chemical imbalance or something of that ilk – and I don't think it is genuinely learned or chosen by any sizable gay population. Humans are full of preferences that don't have clear biological or environmental roots. When you flip a coin there are only two possible outcomes, and which one you get depends on a dizzyingly large number of environmental factors and is very sensitive to very small perturbations in the environment. You can not say that some simple cause X causes the coin to land one way and not the other. In the same sense, I think human sexual preferences are the product of dynamic processes which lead to a finite number of relatively stable outcomes but where those outcomes cannot be realistically determined or modified by control over a person's environment. If true, this means there are an indeterminately large number of possible life histories that lead to being gay just as there are for being straight and that no generalisations can be extracted from their study.

--Diderot 11:53, 15 October 2005 (UTC)

I’ve seen some male animals trying to mount other male animals usually unsuccessfully. This is probably as a result of sexual pressure… the dreaded urge to copulate…but this doesn’t make that animal gay. The normal condition of all animals is to lean towards heterosexuality. I would assume that includes humans. I’ve never seen any female animal show signs of being a lesbian so one must conclude that human homosexuality is the result of the human condition and not as a result of any biological or evolutionary condition. Unless there are gay animals about? --Eye 21:47, 15 October 2005 (UTC)

There are plenty of animal models of homosexual mating preference. For example, look up some of Chuck Roselli's papers about gay rams. alteripse 00:09, 16 October 2005 (UTC)

I'm convinced that homosexual female dogs do exist. All they need to do is lick each other to have sexual relations and it is already known that the two may have dominant relationships to each other that would make them monogamous and attracted to each other, resisting advances from males. In fact, there were gay penguins at a zoo that refused to mate with females despite strong attempts to do so by scientists. They found that the social relationship the two males shared was great enough that the biological comfort of sexual intercourse with females simply wasn't enough to change their minds.14:35, 17 October 2005 (UTC)

See Non-human animal sexuality, in particular the sections on Sheep, and the Spotted Hyena.-gadfium 00:34, 16 October 2005 (UTC)

In those studies, it seems that the more female-geared rams are more aggressive and have higher amounts of sex hormones that drive them to urge for sexuality14:35, 17 October 2005 (UTC)

Interesting reading--Eye 23:15, 16 October 2005 (UTC)

venomous snakes

My 6 year old son asked me if venomous snakes can kill other snakes. Can they and if so – do they? I can find no information on this. Thanks. Shelley --69.205.133.224 18:44, 14 October 2005 (UTC)

Snakes eat other snakes which usally leads to the death of the eaten snake. Being venomous usally helps in the killing but isn't always necessary --Eye 19:32, 14 October 2005 (UTC)

Snake has the answer and the answer is yes, venomous snakes eat other snakes and they use their venom to kill their prey (including other snakes):

All snakes are carnivorous, eating small animals including lizards and other snakes, rodents and other small mammals, birds, eggs or insects. Some snakes have a venomous bite which they use to kill their prey before eating it. Other snakes kill their prey by constriction resulting in death by strangulation. Still others swallow their prey whole and alive.

Another interesting question would be, If a snake gets bit by another snake with the same kind of venom, will it die? --Quasipalm 19:45, 14 October 2005 (UTC)

How could it? Venomous animals must be immune to their own species's venom, right? How else could their bodies produce it? Brian Schlosser42 19:54, 14 October 2005 (UTC)

Not necessarily. The poison they produce is kept in a special poison gland, not in their blood. For example, the hydrochloric acid we produce in our stomachs is quite poisonous to many types of bacteria, and would be so to us, if it were injected into our bloodstream with fangs. However, in a properly functioning stomach, with a nice mucus lining, it's not a problem. This said, many species will have at least a partial immunity to their own poison, as battles with other snakes of their own species are common, and such immunity would therefore be advantageous. If they eat prey which they have injected with their own poison, they will also ingest some that way, although it will be far more dilute by the time it has spread throughout the victim's body. Some types of poisons, like nuerotoxins, can more easily be defended against, say by blocking the nueroreceptors for that toxin, than others, like strong organic acids. StuRat 21:03, 14 October 2005 (UTC)

A little googling finds some interestring but contradictory results. A bunch of tiger snakes and copperheads thrown in together may eat each other but are immune to each other's venom [39]. Vipers and rattlesnakes have blood components that neutralise their own venom but cobras have a protection at the DNA level: their venom has a neurotoxin that doesn't match their own receptors [40]. Or, conversely, "The Prairie rattlesnake is not immune to it’s own venom" [41]. Notinasnaid 07:26, 15 October 2005 (UTC)

Chemistry lecture

A couple of times (once in high school, once in college), I saw a demonstration in which a solution was created then allowed to sit for a few minutes. At a certain time (which apparently can be predicted through calculations), the solution instantly turned from colorless to black. What components were used, and what is the mechanism which causes the color change?

Sounds like the "blue bottle reaction" in reverse. That one is NaOH, glucose & methylene blue, which starts out deep blue, and gradually fades to colourless. Shaking it makes it blue again. --Bob Mellish 19:08, 14 October 2005 (UTC)

The reaction is called the iodine clock reaction, and yes we really ought to have an article on it! In the meantime, a Google search will show you plenty of sites with videos etc. The chemistry is quite simple, there are two reactions involved:

2I⁻ + H₂O₂ + 2H⁺ → I₂ + 2H₂O (slow)

I₂ + 2S₂O₃²⁻ → 2I⁻ + S₄O₆²⁻ (fast)

All the time there is thiosulfate present in the mixture, the iodine is reduced as quickly as it is formed. Once the thiosulfate has all reacted (it is the limiting reactant), the concentration of free iodine (or strictly of the triiodide ion) increases and gives the characteristic blue colour with the starch which is also in the solution. This site gives a description of the Briggs-Rauscher reaction, which is similar in principle but which oscillates backwards and forwards between dark blue and colourless. Physchim62 19:20, 14 October 2005 (UTC)

Stub created! --Quasipalm 19:38, 14 October 2005 (UTC)

Eaten Up

Why do we eat? I know that we eat to live and if we do not eat we would die but dieing only explains what would happen if we did not eat it does not explain why we do eat.--Eye 20:12, 14 October 2005 (UTC)

The main reasons we need to eat are: 1. Food contains energy as sugar, carbohydrate and fat. Without this energy, our muscles cannot move, our brain cannot work and our cells cannot grow. Therefore you die. 2. Food has lots of proteins. These long strings are broken down into smaller chemicals which are then used to make up important organic chemicals such as DNA. Without this, you die. 3. Food also contains salts, vitamins, minerals and other chemicals, such as iron, calcium and vitamin C. These are vital to help our body to keep itself running properly, and without them, our organs, blood, muscles and bones would stop working correctly and cause you to die. smurrayinchester^{(User), (Talk), (Recent Contrib)} 21:34, 14 October 2005 (UTC)

From an evolutionary approach, I would say that organisms which lacked the desire to eat died before passing on their genes, so those that are left largely have this instinct. There are still some individuals who are able to suppress this instinct, such as those with anorexia, but those genes may be selected against after some of them die childless. As for how the desire to eat developed in the first single-celled animals, I would say it developed over time. A plant cell absorbs nutrients from it's surroundings. An animal cell has the ability to move, and eating may have initially just meant moving to an area high in nutrients and absorbing them. The next step may have involved releasing an acid when in the neighborhood of such nutrients to aid digestion. The next step may have been to enclose the nutrient in a vacuole (a sphere inside the organism), and then adding digestive fluids to the vacuole. This might be the first thing that we would recognize as "eating". Next came a tube shaped digestive system, then came all the rest. StuRat 21:45, 14 October 2005 (UTC)

Or, we eat because we are hungry. Unfortunately, our article on hunger doesn't make much of this. - Nunh-huh 02:27, 15 October 2005 (UTC)

OK.Why do we get hungry? :-)--Eye 21:02, 15 October 2005 (UTC)

Ok, now I am guessing you are asking why we get hungry when we seem to have had enough to eat. This is a consequence of evolution. For most of human history, starvation was a threat, so putting on fat whenever we could was a good survival strategy. Salt, protein, fat, and cholesterol were hard to come by but vitamins and fiber were in abundant supply. So, those people who craved as much salt, protein, fat, and cholesterol as they could find tended to survive and pass on their genes. Those who preferred grains and veggies tended to die from starvation. Now, we are stuck with those cravings, despite having all the bad stuff we could ever want at our fingertips. Don't worry, in a few hundred thousand years evolution should catch up to our current food supply. StuRat 22:54, 15 October 2005 (UTC)

Perhaps this is just me – I could stand to lose a few pounds, I know – but I sometimes eat for fun. Food tastes good, be I hungry or not, and I'm pretty sure my attachment to cheesecake transcends the explanatory power of any current theory of evolution. George 21:06, 15 October 2005 (UTC)

DDT

How is dichloro diphenyl tricholobenzene produced? What chemicals are needed to synthesize the chemical

Does the article DDT help at all? --hydnjo talk 21:27, 14 October 2005 (UTC)

It is not specific enough.

Neither is your question! DDT is produced by the reaction of trichloroethanol with chlorobenzene. What else do you want to know? Physchim62 09:14, 15 October 2005 (UTC)

Please not that [[DDT] is a toxic and banned substance. DO not try to produce it! AnyFile 15:55, 15 October 2005 (UTC)

I know that DDT is made with trichloroethanol and chlorobenzene, but I am a grade 9 student, I am doing a project on DDT can you give me some information on these three chemicals?

If you have a PowerPoint reader, this file provides a digramatic representation of the trichloroethanol and chlorobenzene reaction and shows that sulfuric acid is used as a catalyst. This file has a story about how to make DDT at home (third chapter). This file may be useful, too. A webpage for trichloroethanol --JWSchmidt 02:23, 16 October 2005 (UTC)

why do I suffer from sole and heel pain from jogging and walking?

Do you suffer from Diabetes (Diabetes mellitus)? I don't mean to make this into a "20 Questions" thing but am just asking the about one of the more obvious causes for this kind of pain as a rough triage. --hydnjo talk 23:05, 14 October 2005 (UTC)

I've read once about a condition where the heel bone presented a spike-shape. This caused acute pains on the sole and heel. \ Edit: Found it. The condition is called heel spur [42] ☢ Kieff | Talk 23:17, 14 October 2005 (UTC)

It may not be a medical condition—it's possible that your shoes aren't appropriate to the activities you're engaging in. Particularly if you're jogging on a hard surface like concrete or asphalt, you can do unpleasant things all the way up your leg and into your back. TenOfAllTrades(talk) 02:58, 15 October 2005 (UTC)

• Wikipedia does not give medical advice. →Raul654 03:02, 15 October 2005 (UTC)

• Thanks for bringing this to our attention. I forgot and got wrapped up with the question. :-( --hydnjo talk 03:20, 15 October 2005 (UTC)

• As stated in our guidelines, you should speak to your doctor and see what he or she says.Capitalistroadster 07:33, 15 October 2005 (UTC)
  • The disclaimer doesn't state that we can't give our own medical opinions though, does it? I see a lot of answered questions on the desks that refer to legal or medical matters, we're not gonna get in trouble for it surely? --Ballchef 07:49, 15 October 2005 (UTC)
    • No. We just have to point out that it's not official advice, and they should check with a real doctor/lawyer before doing anything. Superm401 | Talk 23:15, 15 October 2005 (UTC)

Some points concerning wikipedia "medical advice":

1. Do respond to questions with generalities: "the common causes of your symptom are"
2. Do use the subjunctive; this is what it's for.
3. Do always indicate the hypothetical/probabilistic nature of your response or the level of confidence in it (which might not be high).
4. Do think of your answer as telling them what to expect from a doctor, not as a substitute for seeing a doctor.
5. Do remember how often first answers here get corrected or modified.
6. Don't forget that people often omit a crucial detail, and the story might change substantially after some questioning.
7. Don't tell them how to treat themselves. Tell them what a doctor might suggest for a similar problem.
8. Don't ever give anyone grounds for saying "he disuaded me from getting medical attention."

It never ceases to amaze me that people will have their insurance company spend $250 for them to explain exactly what is wrong to a person who is trained to help, experienced with that kind of problem, and responsible for what he recommends. And yet they sometimes think free advice based on 1 minute of consideration of 2-5 pieces of information by anonymous strangers with unknown training, experience, and no responsibility for what happens would trump it! alteripse 00:03, 16 October 2005 (UTC)

Helianthus anuus

What water, nutrient and soil requirements are needed to grow Helianthus anuus in a glasshouse environment? sarah

Do you mean Helianthus annuus? If so this is from a Google search. Our article Helianthus annuus may also be of some help about growing Sunflower. You'll also need a tall glasshouse/greenhouse! --hydnjo talk 00:28, 15 October 2005 (UTC)

Self-sustainment

Could a species, without outside food sources, sustain itself on its own dead? The example I have in mind is cockroaches. ♥purplefeltangel ^(talk) ♥ ^(contribs) 05:00, 15 October 2005 (UTC)

Define "sustain itself". For how long? I guess, depending of the species, cannibalism could keep a few alive for a while, but that wouldn't last long enough... The population would drop at a decreasing rate, though. ☢ Kieff | Talk 06:16, 15 October 2005 (UTC)

Define "outside food source". If you count the sun as an outside food source, the answer to your question is "No".

I suppose you mean something like biosphere II without the plants. Nutrients are lost through feces. If these are not transformed to something edible for the animals (whcih plants do) then the population will eventually strarve to death. DirkvdM 09:24, 15 October 2005 (UTC)

Yes. Bacteria are really good at this. Fungi less good but using spores can decrease their need to eat to as close to nothing as you want. Insects can survive a very long time on very little. Snakes (some or all?) can respond to little food by using nearly all their own tissue (and regenerate it later). Imagine a giant meteor hits Earth, kills the dinosaurs, and puts the Earth in a dark winter for decades. Plants die. Everything big dies. Most warm blooded things die. Life forms that eat dead and decayed stuff (the insects) do well. Insect eaters survive. Maybe a few eaters of insect-eaters survive. The exact answer for your question requires a specific species, number of living initially, and lengh of time. Millions of roaches could last centuries I would guess before the last two died. 4.250.198.246 09:55, 15 October 2005 (UTC)

Yeah, but in the end they'd all die, so the answer is still no then. If a meteor would kill everything except bacteria they would survive because of the different metabolisms of different bacteria (some producing oxygen, others comsuming it and such). But there's also the possibility of evolution. If they could survive off each other for long enough then maybe enough different bacteria could evolve to produce a complete ecosystem again, with fully complementary metabolisms. DirkvdM 10:58, 15 October 2005 (UTC)

That doesn't get round the problem of the Second law of thermodynamics. Life is fundamentally organised; to create this organisation from less organised starting materials, it must "spend" energy. For the vast majority of life on Earth, the ultimate source of this energy is the Sun. No sun, no life (eventually), except if you have adapted to live in a hydrothermal vent. Physchim62 14:17, 15 October 2005 (UTC)

Okay, this is the specific scenario I had in mind: Everything on Earth dies. But the roaches, because they're smart like that, move to another planet. There are no other species on this planet, but there is a light source and there is water. If every roach on Earth was living on this planet and they ate their own dead -- at first killing the weakest, but later on eating those who die of natural causes, wouldn't they be able to sustain themselves indefinitely? Don't forget that cockroaches can have up to four hundred babies at a time. ♥purplefeltangel ^(talk) ♥ ^(contribs) 18:35, 15 October 2005 (UTC)

The amount of babies is irrelevant. If there is not only no food source but no other energy source either then you get a biosphere II with only cockroaches and even wthout the sun coming in. That means they have to find a way to convert their lost energy into a form they can consume again. And for that they need plants. Cockroaches are much further developed than bacteria and therefore not quite as flexible. They are notoriously resilient, but I dont' see them pulling this one off. Maybe you should stop watching MIB. :) DirkvdM 18:51, 15 October 2005 (UTC)

Never even seen that movie. :P This grew out of a discussion about the armageddon with one of my friends. Purplefeltangel (talk) 19:22, 15 October 2005 (UTC)

The roaches would have to (re-)evolve photosynthesis, and fast! Bacteria in culture cannot manage it (they all die if you starve them), so I don't expect that roaches would be able to either. Physchim62 19:39, 15 October 2005 (UTC)

Ah, but that's just a 'few' bacteria in a petri dish. But what if you take all the bacteria inside all the cockroaches in the world. If the cockroaches would manage to survive off each other for a few decades then it is quite conceivable that some bacterium that survived inside those roaches would evolve to do photosynthesis. What is the length of a bacteria generation? If it's one minute then we're talking about tens of millions of generations. In human terms that would be close to a billion years, and life has only existed on Earth for a few billion years, so even a whole lot less should suffice, I'd say. DirkvdM 09:18, 16 October 2005 (UTC)

October 15

Scanning material

What sort of page scanning speed can one expect given the following:

• A fairly low-end scanner.
• A resolution good enough to give an image able to pick up average newsprint font size and reproduce it so it's easily readable to the eye (no OCR involved).
• A desire not to have to be very careful about lining up each page on the flatbed.

Essentially, it occurs to me I have lots of reading material I'd like to get rid of (to give me more room and for profit) and I'm wondering how quickly I could scan through the entirity of an old magazine but keeping the filesize/time down. --bodnotbod 07:18, 15 October 2005 (UTC)

Another consideration. How much time would it cost, how much is your time worth (assuming that time is money) and how does that compare to the cost of the space you'd need to keep the magazines. If you don't need to access them regularly you could stow them away in a box so that it doesn't effectively take up space (depending on your living conditions of course). Let's say one scan would cost a half minute. That's roughly 100 pages per hour or one magazine per half hour. One average box of magazines would contain about a hundred. That's 50 hours. Assuming you value your time very low, at 5 euro per hour. That would be 250 euro. How long can you store one box for that? Assuming that is one month's rent for a house that is 30x30x30=10.000 times bigger than the box. So you could store the box for 10.000 months for that price. That's well over 10 lifetimes.

This is assuming you can't do anything else while you're scanning, which is pretty much the case. Believe me, I've tried this sort of thing – even doing the scanning while working on the Wikipedia reference desks wouldn't really work. Another option would be to build a contraption that turns the pages and does the scanning automatically, like the ones used by libraries that are digitising their books. Or maybe you could hire some time on one of those machines. Ask at a library. Who knows. DirkvdM 09:41, 15 October 2005 (UTC)

If I were going to do this, I'd want to score a scanner that did two-sided scanning and had a sheet feeder like most copy machines have. That way, you could just cut all the pages of the magazine off of its binding and shove 'em in the sheet feeder. However, we're beyond "fairly low-end" scanners at that point. Garrett Albright 17:01, 15 October 2005 (UTC)

Bear in mind you talking about something potentially illegal here. The publications are copyrighted. This means you purchased ONE copy. If you scan the media into computer, then dispose of the original dead tree copies, you now have created two copies (even though you got rid of one, either by give away or sale), perhaps #3 as backup, which violates you bought one. You could physically destroy the original media, and be in compliance in spirit but then if the copyright police find you in possession of the scanned copy, you'd need to prove you destroyed the original, which can be difficult to prove without the destruction evidence. AlMac|^(talk) 19:06, 15 October 2005 (UTC)

Well, that would be inherently impossible to prove. But isn't one allowed to make at least one copy for oneself? And does that depend on the country or is there an international law on this? And anyway, would the copyrights police (is there such a thing?) really be bothered? DirkvdM 08:46, 16 October 2005 (UTC)

In the US, I believe you have the right to one backup copy, which would be the scanned magazines. However, I am not a lawyer. Superm401 | Talk 20:28, 16 October 2005 (UTC)

• Hmm, well I think DirkvdM has put me off the idea, I think I imagined that you could get a cheap scanner know that would scan a page in a couple of seconds, such is the rate of progress in some areas. As for the copyright, whilst I try to remain scrupulous about such things for Wikipedia, I wouldn't be averse to, how can I put this, explore the current boundaries of what one is allowed to do with one's reading material in the safety of one's own bedroom. No, wait: that's not what I meant to say at all. Thanks all. --bodnotbod 21:15, 17 October 2005 (UTC)

How can you tell if a plant is male or female?

My 8 year old daughter has chosen this as her independent research project at school. I have used Google and Yahooligans to search for info but can find nothing that explains it simply enough for her (and me) to understand. Any help would be gratefully received.

Have a look at the article on plant sexuality. For an example of a plant that is unisexual (which means it has a "reproductive structure that is either functionally male or functionally female"), see begonia. David Sneek 09:24, 15 October 2005 (UTC)

For some nice pictures, see stamen and carpel (respectively the male and female sexual structures in plants). Physchim62 09:29, 15 October 2005 (UTC)

Flowers are the most reliable indication to discriminate between species (if they have flowers at all), so I assume the same will be true for discriminating between sexes. But flowers differ enormously between plants, so I don't think there will be many general indicators. The most obvious one is that male flowers produce a powdery stuff called pollen, but that is only during a very short time in the lifecycle of the plant. Other than that, I know that in hemp the female leaves are usually somewhat braoder than the male leaves, but that also varies between varieties of one species, so it's only a very vague indicator unless you know which variety yo're dealing with. DirkvdM 09:57, 15 October 2005 (UTC)

Fruit is only produced by female plants. It is defined as the ovary of a female plant, containing either fertilized or unfertilized seeds (ova). However, there are other things that look very much like fruit, produced by other plants. StuRat 22:42, 15 October 2005 (UTC)

I do know that if you crowd dope plants together they will produce largely male plants but a single plant grown on its own will more often than not grow into a female. The logic behind it is because a crowd of females will drop their seed in an area already populated by dope plants. The result is the species does not spread far. However if a seed does find its self on its own and thus in an area not populated by dope plants it would be best to turn into a female to catch wind blown pollen from the group of males. We are not talking huge distances here but what the heck who's in a hurry :-)--Eye 21:17, 15 October 2005 (UTC)

I suppose you're talking about hemp here. I don't think you can really say they determine their sex based on the circumstances. Hemp (dope or not) is a hermaphrodite, meaning a female plant can produce male flowers (and vice versa I believe). They do this when, after a while, they're still not pollinated. And the much stronger reason is that if they didn't they might not get any offspring at all. DirkvdM 08:54, 16 October 2005 (UTC)

Electricity

If electricity is defined as a flow of particles, electrons or whatever does this imply it has some sort of volume? If so what volume is reduced when electricity flows and how was it created. I have some understanding of comparisons with hydraulic systems when talking about electrity flow and pressure.60.229.174.15 10:48, 15 October 2005 (UTC)

In hydraulic terms, electricity is essentially incompressible. However some materials do change volume when electricity flows through them: see electrostriction. Physchim62 14:21, 15 October 2005 (UTC)

Thanks. But I am still having trouble with this volume and substance thing

bascially, assume that electrons don't take volume. electrons are way to tiny to take up any space and remember that we're dealing with a sub-atomic phenomenon. electrons do take some volume but it is so little and it does not result in any measureable effect. The most of the volume of anything is made up mostly of empty space caused by electrostatic repulsion... Sasquatcht|c 08:12, 16 October 2005 (UTC)

While electricity does "flow," it only has "volume" on a trivial level. The rate of the flow, i.e., the number of electrons traveling past a given point per second, is measured in amps, while the pressure of the flow is measured in volts, but nothing more similar to volume than that exists with regard to electricity. --Frostyservant 17:09, 22 October 2005 (UTC)

Mass of bacteria in the human body

Does anyone know what mass fraction of the human body is composed of bacteria? That is, if you took all the bacterial cells out and weighed them, how much mass would that be compared to the mass of the whole body? —Keenan Pepper 16:59, 15 October 2005 (UTC)

Just to clarify, I'm talking about a normal, healthy human, although I think you'd have to have quite a bad infection to significantly add to the mass of normal bacteria. —Keenan Pepper 18:17, 15 October 2005 (UTC)

It depends on whether you include Mitochondria. These were originally proteobacteria, a major group of bacteria that started living in symbiosis with other lifeforms so early that most now have hem in every cell of their body, where they take up 25% of the internal fluid of those cells. And since we consist fully of cells and fluid constitutes the major part of our weight you could say that they constitute some 25% of our weight. (Although I'm not sure every cell has them, such as in bones.) But that's probably not what you were thinking of. DirkvdM 18:33, 15 October 2005 (UTC)

Oh right, I didn't even think of that. But besides mitochondria, what's the mass of all the "true" bacterial cells? Bacteria in the human body says there are about 10 times as many as human cells, but what is their average mass? —Keenan Pepper 18:43, 15 October 2005 (UTC)

Using the article you linked to above and this webpage [43] you can calculate 1x10¹⁵ x 1x10^-12g = 1x10³g or 1 kg. I think bacteria can range in weight a fair bit. No idea how close to right this is. --Martyman-(talk) 23:38, 15 October 2005 (UTC)

Nearly all the bacteria are topologically outside our body: on the skin, and in the gastrointestinal tract. Intestinal contents do not acquire a large bacterial component until they reach the colon, but bacteria do represent a substantial fraction of feces (though less than half of the fecal mass). So maybe a kg worth of bacteria in your colon at most, probably less. While we have zillions on our skin and in our mouth, they would probably not add up to more than an ounce (30 g) by themselves. There should be no significant amounts amounts of bacteria anywhere else in your body. alteripse 00:17, 16 October 2005 (UTC)

Even when you're sick? Are we talking about about bacterial mass of, say, one percent of the human body here? (Probably not, I guess.) DirkvdM 08:58, 16 October 2005 (UTC)

If you exclude the bacteria on skin and hair, in the mouth,, and in the gut, there should be close to zero bacteria anywhere else inside you. When you are sick, bacteria may proliferate, but even with an abscess full of pus, most of the mass of the pus is necrotic tissue and immune cells and fluid, not bacteria. The bacteria in your colon might be around 1% of your body mass, but those elsewhere probably do not exceed 0.001% of your body mass. You will die long before an infection in your blood produces another kg of bacteria. alteripse 16:43, 16 October 2005 (UTC)

Overheated Glass

What happens when glass overheats? Does it expand? What are the hazards of a glass pot left on a hot stove, and would it be safe to pour water in it?

If you heat glass to a high enough temperature (1000-2000°C), it will simply melt. Your stove probably doesn't get anywhere near that temperature, so your glass pot can't "overheat". Pouring cold water in it is a different story, because glass does expand when heated, so a rapid change in temperature may cause it to crack as some parts contract faster than others. —Keenan Pepper 17:23, 15 October 2005 (UTC)

Glass does of course expand when heated, and contract when cooled, which as Keenan Pepper explained, could cause cracking. However, if the glass was extremely hot(unlikely), the water poured could become steam and possibly cause steam burns. Superm401 | Talk 20:27, 15 October 2005 (UTC)

I've had a coffee pot crack because the glass has a different rate of expansion than the metal band around the neck of the pot. StuRat 22:35, 15 October 2005 (UTC)

Musical Statues

Why is it so difficult to remain perfectly still? If someone tries not to move a muscle, they end up twitching or shaking. Surely it should be easier to stay still than to move! smurrayinchester^{(User), (Talk)} 17:18, 15 October 2005 (UTC)

Nothing is ever still--Eye 17:31, 15 October 2005 (UTC)

Even when you're trying to keep some part of your body still, your muscles are pulling on it from different directions. If the muscles aren't perfectly in balance, it will move to one side or another. That explains why it's easier to keep your arm still if it's hanging at your side (muscles mostly relaxed) than if it's raised above your head (muscles pulling in opposition). Also nerves have a lot to do with it... —Keenan Pepper 17:33, 15 October 2005 (UTC)

An analogy that might help you think about this might be:

You and your friend are playing tug of war with a rope. Lets decide neither of you want to win but rather want to keep the rope perfectly still. If your friend pulls harder, you'll need to pull harder too; the same goes for pulling less hard. Will the rope be perfectly still? Probably not -- it will wobble back and forth while you both try to keep it still.

This is in a way what happens with your body. When you try and hold your hand still in a certain pose, it is actually using an entire groups of muscles that all must be in perfect balance. This is why you'll notice wobbles. However, if your hand is in a perfectly relaxed pose with very few muscles in use, you should be able to hold still without much problem. --Quasipalm 03:48, 16 October 2005 (UTC)

Also, muscles don't have a smooth/continuous force range – each muscle has a certain number of bundles controlled by a certain number of nerves. To maintain a precise force, some of the bundles have to relax for some of the time, which introduces small tremors. (The effect is more pronounced on the smaller muscles, which don't have as many bundles as larger muscles such as the gluteus maximus. For some reason I'm thinking of analog/digital signal conversion...) Tzarius 11:05, 21 October 2005 (UTC)

Mammals and other "advanced" life has evolved to maintain a dynamic "balance" for ever faster responses as individuals and species. WAS 4.250 00:25, 26 October 2005 (UTC)

Web technology

I'm opposed. George 21:00, 15 October 2005 (UTC)

I agree. Web technology sucks. gkhan 23:15, 15 October 2005 (UTC)

Especially those new-fangled wiccas. Superm401 | Talk 07:50, 16 October 2005 (UTC)

No kidding, we should burn all wiccas at the stake! just like the old days... Sasquatcht|c 08:07, 16 October 2005 (UTC)

What the Wuck is a Wicca? DirkvdM 09:02, 16 October 2005 (UTC)

Earth and sun

How fast dose the earth spin around the sun? Name:aidan McCarthy Age:8

• The Earth takes one year to go around the Sun.
• The Earth takes one day to go around itself.

AlMac|^(talk) 19:10, 15 October 2005 (UTC)

The Earth revolves around the Sun once a year, and it's 150 million kilometers away, so the total distance it travels in one year is 2 times pi times 150 million kilometers, or almost a billion kilometers every year. That means its speed in relation to the Sun is about 30 kilometers per second. In other words, really really fast! —Keenan Pepper 19:14, 15 October 2005 (UTC)

The Wikipedia article on Earth has a lot more facts about the Earth, like how big it is and how much it weighs. —Keenan Pepper 19:18, 15 October 2005 (UTC)

The weight?? Don't you mean "mass"? Dismas|^(talk) 00:12, 16 October 2005 (UTC)

Well, it weighs something in the gravitational field of the Sun, right? That's why it's falling (accelerating) toward it. But you're right, I meant mass. —Keenan Pepper 01:35, 16 October 2005 (UTC)

Adian, you might be interested in our "WikiBook" titled Wikijunior Solar System which has a lot of information on the solar system and is written especially for children. Garrett Albright 04:15, 16 October 2005 (UTC)

The Earth does not take one day (as in 24 hours) to turn around its own axis. That's just the way it seems from the Earth's surface. Suppose the Earth would not turn around its axis. Then, over a year, you would experience one 'day' (as in a day/night cycle). Thus, there is always one day/night-day more than the amount of axis-rotations. DirkvdM 10:55, 17 October 2005 (UTC)

Minor astronomical nitpick: we should probably distinguish between a solar day and a sidereal day. The former is (roughly) how long it takes for the sun to return to the same point in the sky on successive days. The latter refers to the time for the Earth to turn once (360 degrees) about its axis; the sidereal day is about four minutes shorter than the solar day.

The sidereal day is important for astronomers, because any star–except for the Sun–will be in the same spot in the sky at the same time each sidereal day. A star that is overhead at midnight (solar time) in January will be overhead at noon (solar time) in July. TenOfAllTrades(talk) 14:48, 17 October 2005 (UTC)

MSN Messenger

Is it possible to figure out when your contacts come online?

• Apart from the message you get when a contact gets online? - Mgm|^(talk) 20:45, 15 October 2005 (UTC)

I am guessing they meant ot ask when they came online, 20 minutes ago or 20 hours ago ? I suspect it could be done if you when online when they came online, as a signal is sent to your computer. However, if you weren't online when they came online, no message is ever sent to your computer, which would make it a lot more difficult. StuRat 22:06, 15 October 2005 (UTC)

The popular Messenger Plus plug-in includes an event log (click Plus > Event Log Window) which shows when contacts come online, change their status, and go offline, all with times. --Sum0 23:18, 15 October 2005 (UTC)

Do note, however, that if you use this, DO NOT install the sponsor. --Pidgeot (t) (c) (e) 23:45, 15 October 2005 (UTC)

Muscular Force

Could someone please tell me what the average force exerted by the brachial muscles (the deltoid to the phalangeal adductors) on an object is?

Michael P. Barrett --86.128.76.18 19:58, 15 October 2005 (UTC)

• How much can you lift in a bench press? Multiply the weight in kilograms by 9.8 (or the weight in pounds by about 21.5) to get the force in newtons. Physchim62 20:12, 15 October 2005 (UTC)

Topology

An anon posted this message in WP:HD. I moved it to here. --User:Mdob (note: there are other messages too, move them to here if you have patience, thank you)

Regarding the metric space and topological group.

Question : Is metric space with group structure topological group?

Yes. A manifold (like an metric space) with group structure is a Lie group, and there is a equivalent definiition in terms of topological spaces. See Lie group#Alternative definitions --User:Mdob | Talk 20:13, 16 October 2005 (UTC)

October 16

PDF autocropping/rotating?

Are there any programs out there which can automatically rotate and crop PDFs down to their main body of text? I download a lot of things off of JSTOR for my studies and I like to print them 2 X 2 to a page, but to do so requires first getting rid of the extra page margins on each page (otherwise the text is printed far too small to read). If I could automate this, it would be great, but I can't seem to be able to do it with any of the programs I have (which includes Adobe Acrobat Professional 7.0). Is there anything out there which can do this? It seems like it would be a not-too-difficult feature to make, on the scale of things. I tried using the "Remove White Margins" setting on the "Crop Pages" screen in Acrobat but that does not seem to do anything at all with JSTOR files. --Fastfission 00:44, 16 October 2005 (UTC)

If I understand you well (wich I doubt), you should try to use Ghostgum GSview. It is a program that lets you view and print .pdf, .ps, .ps.gz files in the formats A3, A4, 11X7, B5, etc, and off course, user defined formats. Please, clarify your question. --User:Mdob | Talk 03:35, 16 October 2005 (UTC)

I think I clarified it as much as I could -- it's not a problem in creating PDFs, it is processing PDFs once I have them. In this instance, I download PDFs of articles from JSTOR, but they are often not suitable for printing the way I want to (saves paper, etc.) unless I spent about 5-10 minutes tinkering with each one of them doing some fairly formulaic things (cropping, mostly). My question was whether there was some way to automate this particular need, which is a pretty standard thing (automatic cropping, for instance, is a feature of many graphics programs). --Fastfission 18:57, 16 October 2005 (UTC)

Do you have Adobe Photoshop? You can program scripts in Photoshop (called "Actions") that can do a series of manipulations on all files in a directory. Photoshop can edit PDF's, but it will turn them into raster graphics first. I would google "photoshop actions" and read some of those results and see if this might work for you. --Quasipalm 03:40, 16 October 2005 (UTC)

I have photoshop, I hadn't thought about trying to use it for this. I'm not sure if it can do the auto-rotating I'm looking for (it might be able to do autocropping) but at least it's an avenue to look into, thanks. --Fastfission 18:57, 16 October 2005 (UTC)

The "Remove White Margins" function in the Crop Pages dialog in Acrobat should do exactly what you want as it eliminates all white space outside all visible data. The reason it does not work in this case is I believe JSTOR stores each page as a scanned image, not as PDF data, even though the file format is PDF. As such, Acrobat interprets the whole page as an image and therefore all visible data. If so, Photoshop Actions would definitely be the best idea here. You can download an AutoCrop action here: [44] and just add a step to the action to do the Auto Rotate. --Canley 03:36, 18 October 2005 (UTC)

How Electrons Stay In a Probability Field Around a Nucleus

How do electrons stay in their probability field without going anywhere? It can't involve strong nuclear forces (mostly inside the nucleus), weak nuclear forces (too long a distance) or gravity (too weak for the masses involved), so I can only assume that they are kept in check by exchanges of messanger photons. Is this correct?

electrons are keep binded to the nucleus by an electromagnetic potential, see Schrodinger's equation. The particle model of exchanging virtual photons is not used at all to explain atoms. See Hydrogen atom. --User:Mdob | Talk 02:25, 16 October 2005 (UTC).

Actually, being bound by an electromagnetic potential in ordinary quantum mechanics is equivalent to exchanging virtual photons in quantum field theory. The difference is that in regular QM the electric field is treated clasically while the electron is quantized; in QFT both are quantized (with quanta of the EM field being photons). Now, it's not very useful to use QFT to explain hydrogen atoms; so many virtual photons are exchanged that treating the EM field classically is just as good and much easier. -- SCZenz 09:29, 16 October 2005 (UTC)

Processes

What is the difference between multithreading and pipelining in a process?

Try our articles Thread (computer science) and Instruction pipeline.-gadfium 05:53, 16 October 2005 (UTC)

h5n1 virus

how do people get the deadly bird flu virus? i realize migrating birds have now carried it to europe from southeast asia where many people have died... but how do you get this particular flu? thanks, sherry

We have a good article on the virus, which pretty much answers your questions: H5N1 – Transmission and Infection ☢ Ҡieff | Talk 14:13, 16 October 2005 (UTC)

Fubini-Study metric from Euclidean metric

I have read that there is a natural way to induce the F-S metric on a projective space, can any helpful soul tell me what it is? Apparently there is a natural way to assign distance between lines passings through the origin, but what that might be escapes me. Thanks -Lethe

Could it be the (acute) angle between the two lines? —Keenan Pepper 16:53, 16 October 2005 (UTC)

Hmm... I had considered angle as a possibility before, but for some reason, it seemed too easy to be the right answer. But after your suggestion and some further thought, I can see for example that in RP1, if you add two lines in the plane by angle, then the slope of the third line (which is the inhomogeneous coordinate of the real one dimensional projective space) is given by

$m_{3}={\frac {m_{1}+m_{2}}{1+m_{1}m_{2}}}$

by the sum of tangents, which bears some similarity to the Fubini-Study metric. But of course that formula will only work for colinear lines, so there's still work to be done. -Lethe | Talk 19:55, 17 October 2005 (UTC)

LCD monitor's picture quality and sharpness

I recently bought a 15” LG LCD (TFT) monitor. The sharpness and quality of picture in the new TFT-LCD monitor is not as good as my previous monitor, which was a Samsung CRT 15” monitor. I asked about this to the dealer from whom I bought the monitor. He said that even though LCD (TFT) monitors cost more than CRT monitors, both sharpness and picture quality would be better in CRT than LCD (TFT). 1) Is it true? 2) If I should get sharpness and picture quality, what should I do? Is the product faulty?

The first thing I would check would be to make sure that your computer is outputting a picture that has the same resolution as your monitor. Due to the nature of LCD displays, they work best that way. For example, my PowerBook's display has a 1024x768 resolution, and when I have the computer's resolution set to 1024x768, the picture is as sharp as a tack. However, if I set the resolution down to 800x600 or 640x480 to play a game or something, the picture becomes more "fuzzy" because the display has to fake a resolution it wasn't built to display. So find out the native resolution of your new monitor, and make sure that your computer is set to output a picture with that resolution. In Mac OS X, click the Apple menu, select System Preferences, click on Displays, and click on the correct resolution in the Resolutions list. If you're using Windows, take your entire computer back to the shop and buy a Mac instead -- or try this. Garrett Albright 16:47, 16 October 2005 (UTC)

Also, using the DVI connector you can get a sharper image than with the VGA connector. --cesarb 01:10, 17 October 2005 (UTC)

The difference between digital DVI and analog properly configured VGA connection to an LCD screen is virtually un-noticable. Most users will be more than happy with the results that can be obtained from an LCD screen but many graphic design professionals still prefer to use CRT for their higher resolution, higher contrast and better colour reproduction. --Martyman-(talk) 03:22, 17 October 2005 (UTC)

Also, I'm not sure if this is still true, but there was the problem that the liquid crystals didn't change state fast enough for gamers. A fast changing image would therefore get blurred. But they're getting better in that respect and maybe they've already caught up with CRT's. DirkvdM 11:01, 17 October 2005 (UTC)

This was indeed a problem with fast-moving action games and sometimes even movies with fast motion, but, at least in this gamer's opinion, it's no longer a problem. My little PowerBook's screen can push pixels around without breaking a sweat. Garrett Albright 15:50, 17 October 2005 (UTC)

Electronic document format

I am choosing a format to make documents in. I am aware of XHTML, OpenDocument, Open eBook and DocBook. (Have I missed any important format?) On what basis can I choose one of these formats? —Masatran 17:49, 16 October 2005 (UTC)

There's also PostScript and GhostScript, as well as PDF and other proprietary formats. As for which format you should choose, what exactly is your target audience for these documents? How will they be reading them? Are you going to distribute the documents over the internet, or send them to a print shop, or both? How much money do you have to spend? These will make a difference in choosing which format to go with. Garrett Albright 19:14, 16 October 2005 (UTC)

I use HTML for two reasons. One is that you can you can easily edit the source, which gives you more flexibility if you have trouble getting the rendered text the way you want it. You can also do this with word processor files like .doc using a simple text editor, which doesn't interpret the source but just displays it. But that isn't designed for this, so it will probably be more cumersome and there certainly won't be as many manuals on how to do this on the Internet (or books for that matter). With html you can also use any simple text editor, but something more elaborate like Mozilla Composer (freeware and the only wysiwyg-like html editor I know of). The other reason is that this is the only format of which you can be pretty sure that everyone can read it, because all operating systems come with a browser (and have done so for at least ten years). This is not only true now, but will remain true for, well, ever, I suppose. Standards change or disapppear, but browsers will always be able to read html (I assume). And as the standard expansions like CSS, XHTML and XML get more widespread (which they pretty much are already) you can start using those too (though you can alsways for your own purposes). DirkvdM 11:14, 17 October 2005 (UTC)

Have you heard of Nvu? It's a fork of Composer which is also freeware and is quite capable as far as WYSIWIG HTML editors go. Give it a try. (I still prefer good ol' SubEthaEdit though.) Garrett Albright 15:35, 17 October 2005 (UTC)

By the way, I forgot, a disadvantage of html is that when you add a photo (or what else?) to a file it isn't integrated, but remians a separate file that can be referenced in different ways. So if you copy an html file, you need to make sure to also copy the files that go with it, and in the same relative or absolute location, or else you'll lose that bit. Is there a way around this? I find it a serious minus point of html. Does xml have a solution for this maybe? DirkvdM 10:12, 18 October 2005 (UTC)

In theory, there is. You could setup a webserver with an SQL server and PHP. The SQL server would then store the images (you'd have to insert them with an identifier), and a PHP script would be used to extract them and display them as images. That means you only have your HTML and the database to manage, or, if you also store the HTML in the database, only a handful of scripts and a database. --Pidgeot (t) (c) (e) 13:07, 18 October 2005 (UTC)

Theory that may be, but it's a horrible idea in practice. Retrieving data from a database like that would be slower and more resource intensive than just nabbing a file off a disk; it's an unnecessary and benefitless complication. Besides, it doesn't answer Dirk's original question as to whether images can be embedded into XML files. Answer: They could, but not in any way that would be meaningful to a standard web browser, AFAIK. Garrett Albright 11:55, 19 October 2005 (UTC)

MHTML is a MIME-based format to store HTML along with images, etc. as a single file. Another solution: OpenDocument makes a Zip archive of the files. —Masatran 16:24, 20 October 2005 (UTC)

SIGFUD

What is SIGFUD? Is it some kind of computer conference? — JIP | Talk 17:50, 16 October 2005 (UTC)

Hmm. I see you've posted an article on it. I don't know where you got the information about "SIGFUD" from, because it sounds quite made-up. Could you add a source to the article? RSpeer 18:11, 16 October 2005 (UTC)

The article looks like a joke to me, and Google returns nothing but the article and a few pages in Slavic. Someone please VfD this article… Wikipedia has kept me up past 4:00 AM again and I need to get to bed. Garrett Albright 19:21, 16 October 2005 (UTC)

User:JIP is a Wikipedia admin. So it seems strange that he/she should create the article and then ask on the Reference desk what it is. I will leave comments on their user talk page to sort this out. Majts 21:03, 16 October 2005 (UTC)

rsd

RSD redirects to Standard deviation. Is that what you're looking for? -- SCZenz 18:02, 16 October 2005 (UTC)

Or reflex sympathetic dystrophy? alteripse 20:17, 16 October 2005 (UTC)

I've created a dab page at RSD; if anybody knows any other things that use that TLA, feel free to add them in. TenOfAllTrades(talk) 14:55, 17 October 2005 (UTC)

Thyroid treatment

When is the best time during the day to give a pill to stimulate the thyroid for long-standing hypothyroidism --

• a. The first thing in the morning before any breakfast.
• b. An hour or a few minutes before the noon meal, on an empty stomach.
• c. With the breakfast meal.

There are no pills that stimulate the thyroid. Thyroid stimulating hormone (TSH) is a protein hormone taken as an injection with an effect that lasts about 1-2 days, but whether it stimulates the thyroid to make the right amount of thyroid hormone depends on whether

• a. the person's thyroid gland failed or
• b. their pituitary failed.

If your pituitary is making plenty of TSH and it was your thyroid that failed, injections of TSH won't do much good. On the other hand, if your pituitary failed, you could take an injection of TSH every couple of days. There are three drawbacks to using TSH as a treatment for hypothyroidism due to TSH deficiency:

• a. It's a shot instead of a pill and most people prefer pills.
• b. It is really expensive, like hundreds of dollars per injection, as compared to about 10 cents a pill for thyroxine.
• c. You would have to have many more blood tests to determine the right dose of the shot compared to using a pill.

So most doctors treat long-standing hypothyroidism not by trying to stimulate the thyroid gland to work again, but by suggesting the person take a daily pill of thyroxine to provide their needs. Like a vitamin, this can be taken any time of the day, has no side effects at the right dose, and is identical to your body's thyroxine. alteripse 20:16, 16 October 2005 (UTC)

Your answer is completely correct until the last sentence. Thyroxine supplement, as it was explained to me by a doctor (since I suffer from hypothyroidism) is a compound that 'binds' very easily to minerals as its processed by your body, and becomes completely ineffective to changing the free t4 level of the blood. It's best to take it on an empty stomach AND well before you plan on eating again, especially eating anything that might bind and render the medication ineffective. Most importantly, take it WELL away from any dietary supplements such as iron or multivitamins. If i have time I would like to qualify this with references, but I can't right now. --jeffmeden

You are correct that it is labeled from the pharmacy to take on an empty stomach because there are foods that bind it and reduce absorption, and there are a few published case reports of people in which the difference of absorption with and without meals was enough to change the dose requirement. Soy is perhaps the most notorious such food for young children. I probably should have agreed with that choice. However, despite this, many people who take it do not pay much attention to whether they take it with food and as long as the TSH levels are satisfactory are getting enough. Sometimes the adherence is enough better if they take it with breakfast every day than if they try to find a time apart from a meal that they get more of it. As far as vitamins and minerals specifically interfering with thyroxine absorption, I am skeptical that they make much difference. If you can cite a paper I would appreciate it. alteripse 20:43, 17 October 2005 (UTC)

After a little googling i found this page which has many references at the bottom, and explains a few noted absorbtion issues. The commonly accepted knowledge is that 'food in general' may slightly decrease levothyroxine absorbtion, as food would to any ingested supplement, considering your body is going after 50 to 150 /micrograms/ per dose, which is an astoundingly small amount. Compare it to a still tiny 80 milligram pain reliever, which is ~1000 times as much medication. --Jmeden2000 21:01, 17 October 2005 (UTC)

Thank you for the references, which appear to support your assertions for at least some people. Perhaps our only difference is how common and how large a magnitude effect this potential interference has. My experience is "uncommon" and "usually minimal or small effect", at least in young people. I will not dispute that it may be more than a trivial effect for some people. alteripse 03:03, 18 October 2005 (UTC)

October 17

water treatment

what is the difference between the water that enters a purification plant and the water that enters a sewage treatment plant? how are the water treatment processes different? 64.12.117.12 00:47, 17 October 2005 (UTC)brittany

See our articles on water purification and sewage treatment. Garrett Albright 03:08, 17 October 2005 (UTC)

Gravity and (substance)

As a sort of follow-up to the "gravity and water" question--are there other substances that would be OK to fall on? For example, a 1000-meter deep vat of feathers, or something of that nature? Meelar (talk) 03:33, 17 October 2005 (UTC)

Haha, yes I guess so. Anything that dissipates your kinetic energy slowly and during a long period of time would do. I suppose sinking on a 1000-meter deep vat of feathers would work in this case, but you'd sink quite a lot on it and probably die of asphyxiation before they could dig you out of there. :P ☢ Ҡieff | Talk 04:28, 17 October 2005 (UTC)

It's actually quite simple(in theory). Here's one way to look at it. There's a physical concept called momentum. Basically, it's mass*velocity. Velocity is essentially equivalent to speed(if you're going in a straight line). So you're momentum is mass*velocity. When you hit, your velocity drops to 0; so does your momentum. The change in velocity is called impulse. Impuse is equal to force* time. Hence, for a given impulse, the greater the force, the less time it takes for the change in momentum to complete. So, if you know your mass(say 40 kg) and the velocity on impact (say 4 m/s), you know momentum on impact(160 kg*m/s). That's the same value as the impulse, since you're going to 0. Then, figure out the maximum force your body human can take(say 1600 kg*m/(s^2) ). Divide impulse by force to get time(.1 s). So for that very contrived example, you need to find a material that will cause you to take .1 or more seconds to stop. Finding that stopping time for a given material is the hard part. :) Superm401 | Talk 06:11, 17 October 2005 (UTC)

In movies they use stacks of cardboard boxes. I'm not sure if they need to be stacked in a certain way, though. And in one Due South episode (I believe the last one) Fraser says it's ok to jump out of an airplane over a field of thick snow because the snow will break their fall. Which it did, but they had to climb out of the holes their bodies created (which of course showed their silhouettes in cartoon fashion) . Then again, that's Due South, so don't try this at home (assuming it's big enough to fly an airplane in in the first place, but I've made that silly joke before). DirkvdM 12:27, 17 October 2005 (UTC)

Historically, landing in snowbanks is safer than *not* landing in snowbanks... but you need to know it's a snowbank, not just 3" of snow over a rock ledge! Jumping into (snowy?) pine forests is good – the branches aren't thick enough to kill you hitting them, but the multiple layerings means that your fall will be broken repeatedly. Shimgray | talk | 20:50, 17 October 2005 (UTC)

I vaguely recall seeing TV footage of some guy setting the new world altitude record for jumping off an aircraft without a parachute. I think the landing spot consisted of a stack of gigantic really soft foam mattresses. I might be misremembering, though. Ilmari Karonen 20:59, 24 October 2005 (UTC)

Update: I think I was misremembering. I found this footage of a guy jumping from a 104.5 m tall crane onto a giant airbag, which I suspect is what I vaguely recalled seeing. Impressive nonetheless, even if I got the details all wrong. —Ilmari Karonen 22:20, 28 October 2005 (UTC)

Database

what is database? what is table? what is tuple? what is relational DB?

What is homework? What is missing indefinite article? What is database article containing? --Robert Merkel 04:14, 17 October 2005 (UTC)

Why are there so many famines in Africa?

I'm not sure if this question would fit under the "Science" heading, but I figure since it has to do with agriculture it's the best place to start. It seems that every few months there is a food security crisis in some African nation, with the most recent one being in Swaziland. I'd like to know why there are so many famines in Africa even in proportion to other less developed areas. Impaciente 03:27, 17 October 2005 (UTC)

Because not all developing countries are anything like equal in living standards. GDP per capita in Iran, India or even Bangladesh, are far in excess of Africa's poorest countries. As to why this is the case, there's a variety of reasons. Some parts of Africa have an extremely variable climate and marginal soils, unlike some of the poor tropical countries which are actually very fertile. Then there's AIDS, which is having a disproportionate impact in Africa and destroying the agricultural workforce.

But the biggest issue by far is the corruption and malevolence that infests African governments at all levels. A lot of African famine has more to do with people being forced off their land due to conflicts of one kind of another than variability in agricultural production. As to the reasons for this, well, there's plenty of blame to go around, and a fair proportion can be assigned to colonialism. --Robert Merkel 04:30, 17 October 2005 (UTC)

I'm going to argue for an alternative theory about African famines, one closer to the one put forward by Amartya Sen. I would first argue that GDP comparisons are ineffective both at the high end and low end of the scale – that it's hard to assert the US is really much wealthier than western Europe, and it's hard to claim that Bangladesh is wealthier than many African countries. Its GDP per capita is lower than Sudan's. Instead, I would look at the fragility of infrastructure and the ability and willingness of the state to mobilise resources against famine.

Sen points out that most famines are very local – most often the state will have large areas that are not suffering from famine at all – and that market forces can easily shift some surplus production into the starving area so long as the starving people have the money to buy it. The state can readily provide enough money to starving people – money costs almost nothing to create. In India, the government responds to famine with New Deal type programmes that put money into local pockets.

In order for this to work, three conditions have to exist:

1. The economy must be monetised. Its transactions must primarily involve trading goods and services for money, not direct barter.
2. The material and organisational infrastructure to move food in significant quantities must be in place.
3. The state must have the credit to be able to spend money freely in the affected areas, and it must have the willingness to do so in response to famine conditions.

I think that much of Africa is missing at least one of these conditions, while in Asia only North Korea – which lacks the first condition – faces any real risk of famine. --Diderot 06:33, 17 October 2005 (UTC)

I directly thought of two old examples that I remembered because the causes were surprising. In Biafra there was a famine in the early 70's I believe, which made me think it was a very poor region. Only later did I find out that it was actually a very oil-rich region of Nigeria. All that wealth (at least what was left after Shell oil took their share) was spread over the whole (populous) country. So the Biafrans came up with the idea of separating from Nigeria so they could keep it all to themselves. Of course this led to war and famine. So in stead of getting rich the ended up being starved to death. The other example was in the Sahel not much later. The reason that was given for that famine was that western medicine had greatly reduced infant mortality. But the tradition was to have many kids (because of the high infant mortality rate), so the population exploded during a time of good harvests. Then, when a bad harvest came, which previously wouldn't have been a problem, it led to mass starvation.

About the GDP issues that Diderot mentions (this has nothing to do with the question). When I first heard of some of the wages in some countries that sounded ridiculous – how could those people survive? But when I went to Africa I noticed two things. Firstly, prices for most goods were as low as the wages (only western goodies like tv's were about the same price (as well as the beer, to my horror)). Secondly, a lot of people use little or no money because in rural (jungle) areas people grow their own food and barter. Which can also take the shape of 'I now help you build your house for free, so in ten years time you can help mine'. Such an 'economy' could not work in the individualised western world. See also GDP#Controversies. DirkvdM 13:02, 17 October 2005 (UTC)

Actually, you'd be surprised at how much American poverty involves barter and subsistence. Rural poverty in particular – not just in America but even in parts of Europe – often involves a combination of land ownership so that costs are lower and subsistence gardening. But, a shocking amount off real income among the urban poor consists of barter and quasi-barter arrangements. Exchanges of services like babysitting, home and car repair, school help, discounted or free goods like old cars and TVs... this sort of lifestyle is not so strange even in America and makes the difference between life and death in some cases. Aboriginal Canadians are also closely tied to semi-subsistence and barter economies that simply aren't rich enough to draw the attention of the tax man even when they aren't protected by treaty, and it wouldn't surprise me to find the same behaviours on American reservations too. The Amish in particular have institutionalised a system of community debts and payments. Just as markets existed in the midst of "really existing socialism" alongside and as a part of the command economy, a significant non-monetary economy persists even in the most developed states. --Diderot 17:07, 17 October 2005 (UTC)

Greed causes famine. We in the west will give to the poor only when the poor are thrust into our living rooms.People think only of themselves.A few weeks ago mob greed saw a run on the petrol pumps even though there wasn't a shortage. There is never enough petrol to fill every tank in one day but everyone was thinking only of me,me,me. A government that is always mindful of greed amongest its voters will put the third world poor bottom of the list. None of us are going to vote for a government which would give the third world a fair price for it's goods because we would end up paying more. If the good land used to provide us with cheap tea,coffee,tobacco or sugar was given over to grow food for local people much of the hunger in the world would stop. Next time you have a coffee think of the family, mother,father,and kids who spend the day, all day, everyday, just managing to pick enough beans to feed themselves. We are all part of the system which causes famine. --Eye 19:31, 17 October 2005 (UTC)

Don't just think about them. There's a capitalist way you can do something about this, by buying Fairtrade labelling products, which ensure that more money goes to the farmers in stead of to middlemen. This started with coffee but expanded to other products. But you also mention governments buying the coffee and such. They don't, private companies do (in most parts of the world). But they could, and that would constitute a socialist solution, which shouldn't cause the price to rise, as you suggest. The government could do exactly what those fairtrade companies are doing, without the market having to wait until some private company applies it to some product. DirkvdM 07:40, 18 October 2005 (UTC)

Personally I am somewhat skeptical about this coffee v. foods theory. The only possible scenario that this theory holds true, in my opinion, looks like this (exaggerated to show my point):

There's a poor country with lots of poor farmers. One man with gun took the land from many poor defenseless farmers and hired only a few people to grow coffee with machines. This Mr. Gun builds a castle and saves his coffee money in a Swiss bank account without spending it locally. People are now without land to feed themselves. Only a few coffee workers are not starving but their lives really suck.

I don't think land use is much of an issue here. If without Mr. Gun, local coffee farmers and workers will always use the earned money to buy their own food. If you pay peanuts for their coffee, they can grow maize rather than buying nothing for themselves with your peanuts. Mr. Gun is the problem.

However, there are also many people without land and jobs. With the introduction of modern medicine, many people otherwise could have been dead are now having a chance to grow up. This is actually a curse to them. Because their people are still having too many babies for their own good. And thir societies lack the means to create more jobs. If 200 are living on a land used to support only 100, some of them would always suffer.

Famines and plagues are the norm on earth. People used to be living like animals all over the world just a couple of hundred years ago. If without the culture and science to support this greatly increased population, all of us could face famine some day. Personally, I suggest that we have as few babies as possible. The ecosystem could be on the verge of a total breakdown if the consumption continues. -- Toytoy 09:14, 18 October 2005 (UTC)

You don't need a gun for this. Money is much more effective. An uneven distribution of money (which is the norm in the world) has the same effect. Only those without it might ressort to using weapons if they're desperate enough. Which is why a 'socilaised' capitalist society (such as in the Netherlands) is a guarantee for the rich to safely remain much richer than the rest. As long as the 'poor' don't starve they won't revolt. Socialism killed the the Communist revolution (which is not to say that that's a bad thing). DirkvdM 10:04, 18 October 2005 (UTC)

I know of some cases where collective farming is the culprit. Socialized Agriculture resulted in farmers being directed to grow cash crops instead of food crops. The cash crops were sold and the money was used to purchase arms to export revolution in neighboring countries, or went into the bank account of corrupt government officials, or both. This was because the farmer was not allowed to decide what crops to grow, but the government official made these decisions.

But in the developed world, the market tells farmers to grow cash crops instead of food crops to buy gasoline. I don't see intrinsically how the two cases lead to different outcomes in case of crop failure. --Diderot 15:58, 18 October 2005 (UTC)

• Whatever you do, don't even consider the possibility that they brought it on themselves, no, no, not people taking responsibility for their own actions, how dare we sacntion such a wacky idea--WwJd 04:29, 20 October 2005 (UTC)

• Please ask yourself, WwJd, would jesus blame the victims of famine for their own misfortune? --Quasipalm 01:38, 23 October 2005 (UTC)

Setting up internet website through a broadband connection

My laptop has Debian Linux Testing with the Apache HTTP Server installed. It has a 256 kbps BSNL broadband internet connection through PPPoE. How can I set up an internet website with this? The webpages are ready; how can a domain name be mapped to my computer? The IP address appears to be 59.92.33.82; is this fixed or will it change everytime I re-connect to the internet? How can I keep it fixed? —Masatran 04:51, 17 October 2005 (UTC)

You need to talk to your Internet Service Provider about getting a permanent IP address. If you don't do this, then the IP address may change; probably not every time you connect to the internet, but perhaps every few months.

You need to register a URL with the appropriate body; which body depends on whether you want a .com, a .net etc address, or a country-specific URL such as .bz. Your ISP may be able to help with this, but they may charge you more than if you do it yourself.

Alternatives to getting a permanent IP address are to have a process on your computer regularly check for changes to your IP address and update the mapping from the URL to the IP when it does, or get hosting from a commercial site (or your ISP) for your website.-gadfium 05:31, 17 October 2005 (UTC)

Your ISP (Bharat Sanchar Nigam Limited?) may try to charge you extra for a static IP. If you try to host a site with a dynamic one, you also may be violating your TOS. Hosting a site can be really annoying without a static IP, though it's possible. As for the domain, you can register one yourself for fairly cheap(<$10). Just search on "domain registration". Price shop a little bit before you buy. Superm401 | Talk 06:01, 17 October 2005 (UTC)

If you really want to do this from your home computer and can't get a static IP, you can look into Dynamic DNS, which I use for my own website. You might also consider whether it might be easier to be hosted elsewhere; these days you can get "virtual private servers" (as far as you're concerned, you've got your own server box with root on it, but many of these are hosted on the one physical box) for less than 10 USD per month. It might be cheaper in India. This also means you don't have to have your computer on all the time, which can easily outweigh the costs of the hosting service. --Robert Merkel 13:20, 17 October 2005 (UTC)

Physics-Kinematics

A roller coaster, of mass 100 kg, is 10 m above the ground at its atarting point, A. It moves down a straight, steep slope of 50 m in length to a point X.

What is the displacement? Is it 10 m or 50 m?

This is my exam question. It asked me to find the velocity of the roller coaster at X, if a frictional force of 20N is acting on it.

How do I find it? My answer was 13.4 m/s (3.s.f). Am I right?

Do your own homework – if you need help with a specific part or concept of your homework, feel free to ask, but please do not post entire homework questions and expect us to give you the answers. -- Ec5618 15:54, 17 October 2005 (UTC)

• We have articles on displacement, kinematics and acceleration, which together should be of great help to you. - Mgm|^(talk) 22:11, 17 October 2005 (UTC)

As far as I can see, without known the incline of the slope, this question is unswerable. Perhaps you misread the question? -Lethe | Talk 01:15, 18 October 2005 (UTC)

Aaaaarg! here is the full answer (using the principle of conservation of mechanical energy):

         R  <--------Roller coaster in t(0), Potential energy:
        /|                                    10*100*10
       / |                                      Cinetic energy:
50 m   /  | 10 m                                   0
     /   |
    R----+
    ^  (48,something)
    |
   Roller coaster at t(1)
 Potential energy=0
 Cinetic energy=10,000 – 20 = 9980

    m*v2                 100*v2
  E=---        ->   9980=-----  -> v2=199,6 -> v=14,13
     2                    2

So, the speed ~14.13, and the displacemente is 50 m. Note: probably your teacher made an error, the problem doesn't make sense with 20N, but it does with 200N. --User:Mdob | Talk 23:12, 18 October 2005 (UTC)

Thats not right, frictional force is acting alone the plane, so the displacement is 50 m, that is the distance the coaster travels, and all anong that way friction tends to stop it with a constant force of 20N. Force is N=kgm/sec^2 energy is Kgm^2/sec^2. The energy spent is going down is mgh=100*9.81*10=9810J the energy spent on friction is Fd=20*50=1000J The final energy is going to be all Kenetic, and is 9810J-1000J=8810J this is 1/2*m*v^2 Solving for v v^2=2E/m=2*8810/100=176.2 We get displacement of 50m v=~13.3m/s I enjoy kinematics. Dominick ^(ŤαĿĶ) 22:32, 19 October 2005 (UTC)

Yeah! Dammit! 20 newtons for 20 joules. damm (and fatal) distraction. --User:Mdob | Talk 23:48, 20 October 2005 (UTC)

Note also that the problem is not about kinematics, but about dynamics (the tree parts of Mechanics are kinematics, dynamics, statics).

Where is Athens?

Athens, Greece or Athens, Georgia? Or maybe you are looking for Atlantis? --Screwball23 14:23, 17 October 2005 (UTC)

All the Athenses are at Athens (disambiguation). TenOfAllTrades(talk) 14:35, 17 October 2005 (UTC)

rockets

why have different countries pursued rocket development?

Generally, rockets have two uses: one, for missiles such as the MIM-104 Patriot missile, or two, for sending stuff into space, such as satellites and even people. Of course, development-wise, there could be overlap, so technology originally developed to propel space shuttles could be applied to missiles and vice versa. (A third use for rockets is fireworks, but generally nation-states aren't too concerned about those.) Garrett Albright 15:43, 17 October 2005 (UTC)

For world war and world peace. smurrayinchester^{(User), (Talk)} 16:02, 17 October 2005 (UTC)

It started with the V-series of rockets developed by Werner von Braun for Nazi Germany. For war purposes. Then von Braun was taken to the US where he wanted to develop space rockets, but again he had to build war rockets. And in the USSR Sergey Korolyov faced the same problem, but was more successful in convincing his superiors that space rockets would also serve the cold war effort (spying being one use). But mainly, I believe, the USSR went into space for promotional purposes. This gave them a headstart, after which the US needed a full decade to catch up with them. DirkvdM 09:12, 18 October 2005 (UTC)

chemistry

Is it true that ions are always larger than atoms of any element regardless fo wheter they are anions or cations?

• Not usually. It depends on how you define "size", but my databook says that carbon, for instance, has a covalent radius of 77 pm, but C⁴⁺ has an ionic radius of only 16 pm and C^4- an ionic radius of 260 pm. For most elements it appears cations are smaller, as you'd expect. --Bob Mellish 17:24, 17 October 2005 (UTC)
• Anions are always larger, cations are usually smaller (it can get confusing for transition metals). Physchim62 13:36, 18 October 2005 (UTC)
• For metals, the cations are usually smaller that the atoms. Especially for alkali metals, the ions are definitely smaller than the atom. This is due to 2 reasons. First, the loss of electron(s) result in a loss of electron shell resulting in the ion being smaller than the atom. Second, the net positive charge pulls the electron shells closer. In the case of non-metals, the anions are usually larger than the atom due to reverse.

Why is the brain located in the head?

Don't answer. Its a trick question....ahaaaa!

This is actually an interesting question. Our bilaterally symmetrical ancestors had need for a lot of sensory and motor nerves in the front of the body and connections between them because that was the part that met food and enemies first. Ever since then, the ganglia at the front have been increasing in size and complexity and importance, partly because that need has never gone away. We still meet the world with our faces and have more need for instant response to things which impinge on the nerves in that area. -- WormRunner | Talk 19:53, 17 October 2005 (UTC)

Not all brains are located in the head of an animal, but I forgot which specific animals deviate. It may also depend on what you call a head. Basically, the brain is a concentration of nerves and I believe some animals have concentrations elsewhere as well. Don't worms have a 'node' in each section? DirkvdM 09:16, 18 October 2005 (UTC)

If by "worm" you mean annelid, then yes there is a node in each section, but these ganglia are not the same as the brain, even in earthworms. That said, the only place where the "brains in the head" statement really applies is the annelid/arthropod group and vertebrates. It certainly doesn't apply to molluscs and echinoderms. I suspect the poster was only thinking of human heads. -- WormRunner | Talk 16:19, 19 October 2005 (UTC)

See also octopus. If you have a strong stomach you might also be interested in Mike the Headless Chicken. Shantavira 08:07, 19 October 2005 (UTC)

• Obviously thousands of years of random mutations all added up to form a fully functional human head right out of thin air, nothing far fetched about that--WwJd 04:27, 20 October 2005 (UTC)

• • • Well, in fact that's exactly what did happen, so it is by definition not far-fetched. However, believing a giant mythical man created us in a magical garden 4,000 years ago and then created women from a piece of rib-cage; it makes perfect sense! --Quasipalm 01:36, 23 October 2005 (UTC)

• • As WormRunner mentions, for animals that move primarily in one direction, those that have their sensory organs at the "front" will obviously have a survival advantage, and having the neuron ganglia near the sensory organs would also provide an advantage, both in terms of speed and in terms of efficiency (rather than having nerves carry the signal back to the brain, then back to the organs). WwJd, I don't understand your comment; yes, millenia of mutations resulted in what is now the human head. But I cannot reconcile that statement with the comment about arising right out of thin air. It is true that creationists believe that, and yes, many people find it farfetched, but they may believe what they wish. — Knowledge Seeker দ 05:46, 20 October 2005 (UTC)
  • Yeah! Let's replace it with God, who has the exact same problem! Brilliant! — ceejayoz ^{★ .com} 12:58, 20 October 2005 (UTC)

The pay and college education of a volcanologist...

I was wondering... on average how much a year does a volcanologist get paid? Also, how long do you typically have to go to college for if you are going to work for the USGS?

Thank you. April

• If I remember correctly this question has been answered earlier, please check further up the page and the archives. If the answer isn't there, try one of the other reference desks. - Mgm|^(talk) 22:11, 17 October 2005 (UTC)

April asked the question earlier, but we didn't give her an answer on the pay. April, follow the link in my last sentence for answers about how long you need to go to college for.

The pay varies according to experience. I can't answer for the USGS, but I tried two Google searches: vulcanologist salary and volcanologist salary. From these, it appears that pay ranges between US$30,000 and US$100,000. If you look at these searches yourself, please check what the currency being referred to is – not all positions are in US dollars.

The USGS does give a table of salaries here, but I can't find anything which explains what grade range a volcanologist may be in. This site will only help if someone can find an explanation of grades for scientists.-gadfium 03:03, 18 October 2005 (UTC)

best way to display a dynamic binary tree on the web

I want to display a tree on the web. I did a similar project many years ago when I was a student where I displayed a binary tree in Java. But I'd rather something more native to web browsers. I have a LAMP (apache with php and mysql database on gnu/linux) set up, and I want to dynamically display portions of data stored as a tree (not necessarily binary). What's the best way to render this? I thought maybe CSS. Does CSS have the ability to layout things precisely enough to make a tree? I've never used CSS, so I'm not sure what it's capable of. So can it like, have an outlined box with a picture, some text and hyperlinks in it, and place it according to coordinates that I would calculate, then draw lines connecting various such boxes in a tree shape? The coordinates and slopes and placements of lines would all be calculated in php. So what do you think? thanks -Lethe | Talk 21:01, 17 October 2005 (UTC)

I think the best solution would be either to nest the results within <h1>..</h1> <h2>..</h2> tags (if you dont have that many branches) or nesting using list elements <ul><li> more o less like the following code:

  <ul>
    <li class="level1">Item 1</li>
    <li class="level1">Item 2</li>
    <ul>
      <li class="level2">Sub-Item 2</li>
      <li class="level2">Sub.Item 2</li>
    </ul>
    <li class="level1">Item 3</li>
  </ul>

yields:

• Item 1
• Item 2
• Sub-Item 2
• Sub.Item 2
• Item 3

Modifiyng the base css allows you to costumize indentation and stuff as much as you want, it is something that can be done easily using LAMP too... --Threner 21:41, 17 October 2005 (UTC)

Ummm.... but that's not a tree, that's a list....? thanks though. -01:04, 18 October 2005 (UTC)

It is a nested list, which means it is no different from a tree, you have nodes and leaves... you only have to change the definition of the li element to display any kind of format you like in the bullet... check this example, it is done using css http://css.maxdesign.com.au/listamatic2/vertical14.htm --Threner 03:49, 18 October 2005 (UTC)

I believe the original poster it trying to create diagrams like this: File:6n-graf.png. If you want, you could use CSS to position the boxes: just put each of them in a div, and give it a style attribute like so:

<div style="position: absolute; top: 123px, left: 456px; border: 1px solid black;">graph item</div>

Unfortunately, to the best of my knowledge CSS has no way of drawing diagonal lines, circles or other advanced shapes. Since you already have PHP set up, you might want to try using the GD library (http://us2.php.net/gd) to construct the diagram as an image. Another alternative would be SVG, but that currently requires a browser plugin. --David Wahler (talk) 15:09, 18 October 2005 (UTC)

What caused the big bang?

What caused the big bang?

Flatulence. --Diderot 21:09, 17 October 2005 (UTC)

Have you read our article on the Big Bang and related subjects (particularly Timeline of the Universe)? Of particular (perhaps philosophical) note is the question of whether causality has any meaning prior to the theorized beginning of the universe and its associated physical laws. — Lomn | Talk / RfC 21:24, 17 October 2005 (UTC)

The big bang is a theory which is based on the theory that the universe is expanding which is based on the observation that the light coming from distance stars leans towards the red end of the spectrum the cause of which is based on the theory that light acts as a wave and the wave is being stretched making the light appear reddish. If the universe is expanding then it must have all come from some central point and been blown out in a Big Bang? Hmmmm….. Plenty of room there for debate… --Eye 21:32, 17 October 2005 (UTC)

It's a remarkably successful model of cosmology. It explains all sorts of very different observations about the universe, from the cosmic microwave background to the amounts of different elements. There are no other models that do the same.

If you don't like gravitational redshifting, then you don't like General relativity, and that's an even more well-grounded theory.

Other than that, debate all you want. ;)-- SCZenz 21:55, 17 October 2005 (UTC)

. It's not that I don't like the theory it's just that popular culture often presents it as fact.--Eye 18:23, 18 October 2005 (UTC)

It's the best theory we have at the moment (and it's pretty darn good). Popular culture often presents established theories as fact; for example, the laws of thermodynamics. Nothing special about this one, scientifically. --Ashenai (talk) 18:27, 18 October 2005 (UTC)

The big-bang has been the bedrock of cosmology for 35 years now; the nobel-prize winning discovery of cosmic background radiation was more-or-less the last nail in the coffin. At this point, you'd be hard pressed to find a non-crackpot who has an alternative to it (in fact, someone who disagrees with the Big-bang is a crackpot almost by defintion). →Raul654 01:06, 19 October 2005 (UTC)

Calm down guys and gals I was only suggesting that if something is accepted as fact when it can't be totally proven then we close the door on other possibilities. Don't be a flat earthling. At this moment in time all the doors should be open. --Eye 20:29, 19 October 2005 (UTC)

The possibilities that are plausible should be open. There's only one, at the moment. Come up with another one and I'll be the first to reconsider.. ;) -- SCZenz 20:40, 19 October 2005 (UTC)

• Gee, completly unobservable, unprovable, untestable, seems scientific to me--WwJd 04:25, 20 October 2005 (UTC)
  • Actually, it is observable, in a sense (see cosmic microwave background radiation), and it is quite testable as well. The big bang theory makes a number of predictions, about the intensity of radiation, the rate at which the galaxies recede from each other, the relative amounts of the first elements to form, the age of the universe, and so on. As Raul mentioned above, discovering (accidentally; they weren't even searching for it) the background radiation that the theory predicted was what really sealed the fate of the other models. Of course, nothing is science is provable, so being unprovable is certainly scientfic. At any time, we may make a new discovery which the big bang theory does not explain well, and instead come up with a new model that better explains it; more likely, it won't be enough to invalidate the big bang theory, but will refine it instead. That's how science works. The door is always open to other possibilities; it's just that right now no theory explains the origin of the universe nearly as well as the big bang theory does. — Knowledge Seeker দ 05:40, 20 October 2005 (UTC)

Ah, I sense a subtelty here. As an aside, think of all the theories in the world, and rank them in terms of "absolute truthfulness", on a scale of 0 to 10. 10 being completely true, and 0 being completely false. No scientific theory could ever score a perfect 10, although scientific theories can asymototically approach this value. This is a very healthy thing :-) --HappyCamper 16:08, 22 October 2005 (UTC)

Lunar Question

Is it possible to age the craters on the Moon. Apart from the fact that the younger ones over lap the older ones is there a way of looking at one of the craters and determining its age?--Eye 21:18, 17 October 2005 (UTC)

No, moon craters don't suffer erosion, since there's no atmosphere or water in there. But you can date them using radioistope dating --User:Mdob | Talk 00:04, 18 October 2005 (UTC)

It's not erosion, but I found something that talks about space weathering. [45] "Part of what makes a moon crater look "fresh" is the appearance of a bluish tinge to the surface. This bluish tinge indicates lunar soil that is relatively untouched by a process called "space weathering," which reddens the soil. Another indicator of a fresh crater is that it reflects distinctly more light than the surrounding area." Also see our Geology of the Moon#Geologic history article which states, "The Apollo 17 mission landed in an area in which the material coming from the Tycho crater, which has a diameter of 85 km, had been distributed; the study of these rocks helped come to the conclusion that this crater had formed 100 million years ago. The surface has also experienced space weathering due to high energy particles and micrometeorites. This process causes the ray systems produced by impacts to darken until it matches the albedo of the surrounding surface." Here's a link from NASA about space weathering: [46], someone should start a stub. --Quasipalm 01:00, 18 October 2005 (UTC)

Gentic melding

I have seen many references to hybridisation and cross breeding but true melding. What I mean is pick apart two animal structures and adding them together, getting rid of any duplicate parts. The specific idea I had was a wolf-tiger an animal that contain traits of both animals. This method would not really on the normal methods of half the genetic structure being taken from each parent but the merging of two complete DNA strands. Sorry if I’v repeated mysel (or anyone else) here.

--82.30.242.131 22:20, 17 October 2005 (UTC)

• Whats the question?--inks^T 00:55, 18 October 2005 (UTC)

We don't follow your distinction and suspect it is based on some erroneous assumptions or misunderstanding of basic gene function. Hybridization and crossbreeding, if the offspring are fertile, matches your definition of "melding". What do you imagine is the difference between merging DNA and hybridization to a single genome? alteripse 02:57, 18 October 2005 (UTC)

What is the Geiger-Nuttal Law?

What is the Geiger-Nuttal Law?

October 18

Facial Hair Growth

Does the growth of male facial hair increase by shaving it? Thanks. -Haon 00:40, 18 October 2005 (UTC)

No. From [47]: "Shaving does not make the hair shaft thicker, darker, or grow faster or slower. However, the short hair shaft may be more noticeable as it grows out because it has a blunt tip instead of the normal tapered tip. " Other sources: Mayo Clinic Snopes "Beardguy" on AOL --Quasipalm 00:51, 18 October 2005 (UTC)

LEVERS

hey, are tweezers a first, second, or third class lever?

I would say they aren't a lever at all, as they rely on bending the metal (at least the most common design does). A classic lever does not require the lever-arm to bend. StuRat 16:49, 28 October 2005 (UTC)

Take a look at lever which explains the three classes with examples.-gadfium 02:38, 18 October 2005 (UTC)

While we are on the subject, has anyone encountered this class system for levers outside of a school textbook? Is it used in the real word anywhere?--Commander Keane 14:02, 18 October 2005 (UTC)

And what about state capitals, sentence diagrams, long division, times tables, gym, batik and civics. Useless, useless...Brian Schlosser42 17:30, 18 October 2005 (UTC)

You don't use your times tables?--Commander Keane 17:18, 22 October 2005 (UTC)

Barometer

How does a barometer work?

There are many types of barometers. look in the article and see which specific kind you're looking for. --Borbrav 05:11, 18 October 2005 (UTC)

alligators and crocodiles

Which one, the alligator or crocodile, opens it's mouth by raising it's upper jaw and which one opens it's mouth by lowering its bottom jaw? --68.33.167.172 03:34, 18 October 2005 (UTC)

• Based purely on the photograph on the Crocodile article, I would say the crocodile raises its upper jaw. I can't quite tell from the photograph on Alligator, but it looks like it could open it's mouth by moving the lower jaw. --Canley 03:45, 18 October 2005 (UTC)
  • I was under the impression that everything has the upper jaw as part of it's skull and that the only way anything could open it's mouth is through the articulation of the bottom jaw. --Martyman-(talk) 04:26, 18 October 2005 (UTC)

How to seperate chlorophyll a & b,and carotenoids before doing the Absorption Spectrum of Chlorophyll a

I would like to know the details of the process about seperating chlorophyll a & b,and carotenoids before doing the Absorption Spectrum of Chlorophyll a

Paper chromatography works. first Google HTML hit ("enjoy" the webpage background). I you can read a PDF file, go here. --JWSchmidt 19:41, 18 October 2005 (UTC)

Drugs and Alcohol

My teacher keeps telling us that alcohol is the only drug that affects every organ of the body because it flows through the bloodstream. But what about heroin when you inject it? What about vicodin and other drugs? Dont they also affect every organ?

Come on. If you eat a candy, the sugar will enter your bloodstream (simplified) and every living cell in you body will eventually nurished by the sugar. If you breath, oxygen will do the same thing. If you drink water ...

Sugar, oxygen and water aren't drugs. DirkvdM 09:57, 18 October 2005 (UTC)

Tell that to the principal in Missouri who suspended a child for giving another child a drug: a glucose tablet. alteripse 21:02, 18 October 2005 (UTC)

I don't know what are the receptors of alcohol in human cells. I also don't know if all cells, tissues and organs are responsive to alcohol. I'd like to know the answer. -- Toytoy 09:28, 18 October 2005 (UTC)

That something flows through the blood doesn't necessarily mean it affects everything. Heroin, for example, is much like endorfins (no article on that? I do spell it right, don't I?), so the body accepts it as something natural and uses it where it is normally used, which is in the brain. But then heroin is a substance the body recognises and this is not the only way something can affect a bodily part. DirkvdM 09:57, 18 October 2005 (UTC)

endorphin. -- Toytoy 11:11, 18 October 2005 (UTC)

As with most drugs of abuse, alcohol affects primarily the brain and the liver. Physchim62 13:41, 18 October 2005 (UTC)

Alcohol is highly soluble in water, whereas the other drugs are not. This means it can pass through tissues. When Alcohol

is consumed some of it actually penetrates the tounge and enters the bloodstream that way. Other drugs do not do that, at least to that extent. It also does not need to be digested to enter the blodstream and can be used as food, sort of. There is a story that certian types of diabetics can take in alcohol in an emergency to keep them alive until help arrives. I do not know how true that story is, though. Read it years ago in readers digest.

Not true. alteripse 21:03, 18 October 2005 (UTC)

Read about receptors. Most drugs have actions on specific organs because their recptor-mediated actions are generated only in certain parts of the body. Alcohol has effects on cells that are independent of a specific receptor, allowing it to have effects on all cells. The chemical nature of alcohol that gives it the ability to penetrate to all tissues (see above) is also important. --JWSchmidt 14:01, 18 October 2005 (UTC)

what are the dangers of salvia?

enviroment and its relation with geography

You can find a lot about the environment here at Wikipedia. Environments are frequently affected by geography; for instance, where the geography is below sea level, the environment is usually wet. For a more complete answer, please ask a more complete question. — Lomn | Talk / RfC 13:53, 18 October 2005 (UTC)

QF 25 pounder Short Mark 1 (australia)

Please, does anyone know when the QF 25 pounder was first manufactured in Australia, and by whom? -- Chris

• Our article on the 25 pounder does not contain the information directly, but it does link to LemaireSoft, which refers to a diferent designation: 8.76cm FK 280. A quick google search yields several links, among which this one, which details the history of the weapon. -- Ec5618 11:02, 18 October 2005 (UTC)

Sales of commonplace automobiles

I would like to know the order of magnitude of the yearly sales of some modern average, commonplace model of automobile (with references if possible). David.Monniaux 12:32, 18 October 2005 (UTC)

Within the context of your question, please define the terms "modern", "average", and "commonplace". Dismas|^(talk) 13:16, 18 October 2005 (UTC)

Commonplace = a kind of car commonly bought today (ex: Peugeot 206 in France), i.e. not luxury cars

Average = a market segment that ordinary people buy (i.e. not luxury cars, not sports car)

Modern = produced within the 5 last years David.Monniaux 13:53, 18 October 2005 (UTC)

Automotive Intelligence has compiled a fair amount of information relating to annual sales for various manufacturers. If you want national figures, most nations have an association of automotive importers and manufacturers who compile such things. --Robert Merkel 13:39, 19 October 2005 (UTC)

What is the 'Vero cell line'?

Hello, what is the Vero cell line? Regards, Stuart.

Please, search first – it's quicker. Search Wikipedia using the box to the left. A web search could help too.

A google search yielded this file which explains that The Vero cell line (a single cell line) was derived from the kidney of a normal, adult, African green monkey (Cercopithecus). In addition to its use as a vaccine cell substrate, this cell line has been used extensively for virus replication studies and plaque assays.

The rationale behind the use of Vero cells rather than primary monkey kidney cells is that these cells can be banked and well characterized, which avoids the issues of lot-by- Iot variability and adventitious agent contamination of primary cultures freshly initiated for each production run from the kidneys of wild-caught monkeys. In addition, the continued use of animals is problematic from ethical and economic viewpoints. Numerous investigational products are being produced or have been proposed to be produced in Vero cells. -- Ec5618 17:58, 18 October 2005 (UTC)

Elementary particles

What are WIMP's and MACHO's? Have any been observed so far? Chosen One 17:34, 18 October 2005 (UTC)

Please search first – it's quicker. Search Wikipedia using the box to the left. A web search could help too. -- Ec5618 17:49, 18 October 2005 (UTC)

Hey, you don't have to shout, I can understand normal English, well, thank you. Chosen One 19:12, 18 October 2005 (UTC)

Don't post while intoxicated is my advice. - Cobra Ky (talk, contribs) 04:45, 20 October 2005 (UTC)

I'm sorry, but I wasn't shouting, I was copying the exact rule you should have followed, as it is written at the top of this page. Had you read those rules, you would not have had to ask your question, and your linguistic abilities would not have been doubted. -- Ec5618 20:08, 18 October 2005 (UTC)

Try WIMP and MACHO. — Laura Scudder | Talk 17:45, 18 October 2005 (UTC)

Laptop and digital camera woes

Okay, since the Peanut Gallery answered my spoiled hamburger question so well, hopefully I can get some equally good advice about my laptop...I have an old (2001 era) Gateway laptop as my backup computer. The fan has died, and for a while it worked OK, so I took it to my brother, a semi-pro electronics wiz to repair. However, as the fan is very hard to come by, he can't fix it. Now, it overheats and goes into safe mode in about a minute. Next week I am going on vacation, and will be taking my Fuji S3100 camera with me. I have one 256 Mb xD memory card, and the idea was that I would use the computer for a few miuntes a day to dump the photos. But now, I can't even do that, as it wont stay on long enough to copy the files. So, I had an idea: What if I keep the laptop in the refrigerator to keep it cold? I know thatthis is not usually a good idea, and that condensation is going to be a problem, but frankly I want to take a lot of pictures more than I want to keep the dying laptop. So, will this work as a way to keep it running for a few more days? I won't need it more than 15 minutes a day, for 7 days. Any ideas? Brian Schlosser42 19:25, 18 October 2005 (UTC)

The fridge might help, but the problem is more a lack of airflow (where inside-case temps might pass 150°F) rather than ambient temperature. I think you'd have better luck, and far less risk of a short-circuit, fire, or generally dead laptop, if you created some ductwork with paper and tape connecting a desk fan to the fan vents on the computer. It certainly wouldn't be any more cumbersome to work with than typing in the crisper. — Lomn | Talk / RfC 19:31, 18 October 2005 (UTC)

I have actually used a small external fan to cool my laptop when the internal fan died and it worked reasonably well as long as I wasn't doing anything too processor-intensive. Your mileage may vary. -- WormRunner | Talk 21:29, 18 October 2005 (UTC)

Ok, no 'fridge. I'm going to buy a desk fan to ventilate it, as this seems to be the consensus. Thanks for the advice, folks. Brian Schlosser42 13:26, 19 October 2005 (UTC)

Back in the old days I used freeze spray to cool a desktop – if you were prepared to take it out of it's case I'll be you could do the same thing with your laptop! Trollderella 02:39, 27 October 2005 (UTC)

Some Ballistics

A friend and I have had an ongoing dicussion regarding what happens when someone fires a bullet straight up. As the physic laws state, in a vacuum the speed of the bullet, which is 300 m/s using a common handgun), as it comes down would be the same as when it left the chamber (Parabolic shot). So it would go fast enough to kill someone. However, I believe that because of the small mass and friction with the air the bullet would slow down so much that it is mostly harmless. Am I right? --Threner 21:13, 18 October 2005 (UTC)

Do not try this one at home. The terminal velocity–the bullet's maximum speed as it falls–depends on its mass and shape. It is definitely possible for a falling bullet to cause injury; such mishaps are a staple at U.S. hospitals around the Fourth of July and New Year's Eve. These injuries are sometimes fatal; whether the victim dies (or even suffers serious injury) probably is affected by the size (caliber) of the bullet, how thick his skull is, and a substantial measure of luck.

Don't look up, either. By doing so you expose the soft tissue and thinner bones of the face, and possibly the major blood vessels of the neck. TenOfAllTrades(talk) 21:31, 18 October 2005 (UTC)

Any idea of the falling speed? i the article on Terminal Velocity states that a easy way to calculate the speed would be to tie the bullet to a vehicle using a thin string. When the bullet reaches 45 degrees, the speed of the vehicle is the terminal velocity. I really want to try this at home to calculate how fast does the bullet go while falling. I wonder if a bullet at 100 km/h could kill someone. Still, at least I know that the bullet slows down enough for it to be not necessarily mortal --Threner 21:38, 18 October 2005 (UTC)

• • • I've read (somewhere, I can't find it now), that somebody measure the terminal velocity of a bullet (I don't know what calibre) as ~90 m s^-1. That would be 200 mph or so. --Bob Mellish 23:26, 18 October 2005 (UTC)

If you search Google for 'bullet terminal velocity', you get a bunch of handy references, including (in part) [48]:

"Different bullet types behave in different ways. A .22LR bullet reaches a maximum altitude of 1179 metres and a terminal velocity of either 60 metres per second or 43 metres per second depending upon whether the bullet falls base first or tumbles. A .44 magnum bullet will reach an altitude of 1377 metres and a terminal velocity of 76 metres per second falling base first. A .30-06 bullet will reach an altitude of 3080 metres with a terminal velocity of 99 metres per second. The total flight time for the .22LR is between 30 and 36 seconds, while for the 30-06, it is about 58 seconds. The velocities of the bullets as they leave the rifle muzzle are much higher than their falling velocities. A .22LR has a muzzle velocity of 383 metres per second and the .30-06 has a muzzle velocity of 823 metres per second.

According to tests undertaken by Browning at the beginning of the century and recently by L .C. Haag, the bullet velocity required for skin penetration is between 45 and 60 metres per second which is within the velocity range of falling bullets. Of course, skin penetration is not required in order to cause serious or fatal injury and any responsible person will never fire bullets into the air in this manner."

See also [49]:

"B. N. Mattoo (Journal of Forensic Sciences, 1984) has proposed an equation relating mass and bullet diameter that seems to do a better job. Experiments on cadavers and such have shown, for example, that a .38 caliber revolver bullet will perforate the skin and lodge in the underlying tissue at 191 feet per second and that triple-ought buckshot will do so at 213 feet per second.

Mattoo's equation predicts that Hatcher's .30 caliber bullet, which has a small diameter in relation to its weight, will perforate the skin at only 124 feet per second. It's easy to believe that such a bullet falling at 300 feet per second could kill you, especially if it struck you in the head."

Hope that helps. There are a lot of other sources out there that reach essentially the same conclusion—getting hit by a bullet as it falls at terminal velocity is likely to be painful and is potentially fatal. Larger-caliber bullets are generally more dangerous than smaller. TenOfAllTrades(talk) 04:11, 19 October 2005 (UTC)

Mythbusters did a sort of similar experiment where they investigated whether a penny thrown from the Empire state building would penetrate a skull. They found that there was NO WAY a penny could ever even pierce skin at its terminal velocity (they shot themselves with their experiment-guns to prove it). The terminal velocity for a bullet would ofcourse be alot higher, but from watching that experiment, i doubt that it would pierce a cranium. But don't try it at home :P gkhan 00:16, 20 October 2005 (UTC)

A Penny has a lower terminal velocity than a lead round. Falling lead has injured people, however, I have seen stray rounds from a rifle range bounce harmlessly off of people. A large round would hurt from a ways up; 300 m/s sounds like a pretty slow and large caliber. Dominick ^(ŤαĿĶ) 19:08, 20 October 2005 (UTC)

My brother once dropped an orange from the tower of Pisa (oh, how very original...). It created a rather deep hole in the ground, so he was lucky there no-one passed by there at the moment (not to mention the other person of course). DirkvdM 14:35, 24 October 2005 (UTC)

Domain name transfer

What's the simplest way to transfer a domain name? I noticed that someone had a domain name that he wasn't using, emailed him, and he offered it to me for free so long as there weren't any tranfer fees. However, he probably wouldn't feel comfortable just giving me his username and password. What's the easiest way?

Thanks, — Asbestos | Talk (RFC) 23:46, 18 October 2005 (UTC)

There's not really any transfer fee. In fact, you can start a transfer registration at Dotster(and others) for less than a regular registration(per year). So, it will be less than 9.00 for the entire year after transfer, and you don't have to pay a fee just for transferring. Superm401 | Talk 03:16, 19 October 2005 (UTC)

Thanks. Also, I currently have a domain name registered under GoDaddy, and am thinking of using them for webhosting as well. With most hosting packages, can you share out the space among different domain names? I noticed Ace-host.net seemed to have one domain/one-hosting space only. — Asbestos | Talk (RFC) 04:33, 19 October 2005 (UTC)

I don't know about GoDaddy, but I use DreamHost and am hosting seven domains with one account, so it seems to vary by company. I'm very happy with DreamHost's services by the way, and would recommend them to anyone. Use this link to check 'em out, and if you sign up, I'll get a referrer bonus. :) Garrett Albright 11:38, 19 October 2005 (UTC)

October 19

Ink Markers

Can you please tell me what keeps the ink inside markers? Thank You. Susan Thomas ---01:16, 19 October 2005 (UTC)

You mean keeping it from running out? The little wick on the end keeps the small amount of liquid in the case. It actually is flowing all the time, by evaporation through the wick. When you have the cap on, there is very little evaporation. When you press it to paper, clothing, skin or other items to be marked, capillary action allows the liquid to flow. If there is nothing to flow to, not much comes out. Dominick ^(ŤαĿĶ) 02:42, 19 October 2005 (UTC)

Thanks for the answer...my 9 year old granddaughter thanks you also..

Polynomial bound attainment

Yes, this is homework. But it's only part of the homework, and homework we are encouraged to discuss. And homework whose deadline will almost certainly pass by the time you read this. And yes, me (I, actually) and several others have thought long and hard about this to no avail.

Let P: R^n -> R be a multi-variable polynomial that is bounded below. Does P attain its infimum?

The single variable case can be proven reasonably easily, but the method does not seem to extend to more variables. --Fangz 01:54, 19 October 2005 (UTC)

Try thinking of the question in this way: Let's take P. Can the bounds on P be of the form [a, b]? What about (a, b)? What about {a, b]? What about [a, b}? What about (-ifty, +ifty), (-ifty, b], (-ifty, b), (-a, +ifty), [-a, +ifty)? If you can think of examples/counterexamples, then essentially you would have answered the question. --HappyCamper 03:17, 19 October 2005 (UTC)

UPDATE: The answer, in case you are wondering, is NO. Counterexample is (xy – 1)^2 + y^2, along the curve (t, 1/t). --Fangz

Spaces in fixed-width fonts in Microsoft Office Word 2003

When I use MS Office Word 2003 and type in a fixed-width font like Courier, the spaces between the words can get thinner, giving the appearance of right-hand justification even when the paragraph is marked for being flush-left, not right-hand justified. Is there any way to turn that off? It's very annoying. Thanks! --Angr/_{tɔk tə mi} 08:59, 19 October 2005 (UTC)

Correct me if I'm wrong, but doesn't "flush left" mean that it should adapt the spacing between words to make all lines appear equally long? Use a plain old left justification instead, that'll do the trick. --Pidgeot (t) (c) (e) 14:44, 19 October 2005 (UTC)

For me, "flush left" is the same as left justification. At any rate, it's not supposed to be fiddling with the spaces between words, and it is. --Angr/_{tɔk tə mi} 18:14, 19 October 2005 (UTC)

The Program ( MS Office Word 2003, WordPad and NotePad ) uses what the font gives. Your font happens to have a broken space character, making the font Coueier, NOT a mono-spaced font. ( Mono-spaced, means that all characters, even the space occupy a fixed width. ).

You can test it with this test case Text: ( the final I's should all line up too! )

I IIII I

II II II

III IIII

II II II

I IIII I

If all the Is do not line up, then you have a font problem. It may also be using a printer 's version of the font, and not the comptuers version of the font. ( PostScript Printers do this commonly ). ( What Printer and OS are you using? )

Flush-left means that all the first characters on the lines are in a column down the page, and the last characters do not nessesarly line up. (ragged right). If you are using a mono-spaced font, and you use flush-left, and the lines have the same number of characters, the last letter on the lines should line up.

Justify means that ( even with mono-spaced fonts ) that there are enough spaces inserted between words so that the first and last characters on the lines all line up in colums.

But since your using a Microsoft based product, I would get very familar with all the settings. They keep moving 'Use Fractional Width's' around, which makes most output look even weirder. Artoftransformation 08:59, 31 October 2005 (UTC)

Life on other planets.

If I am correct, the conditions for life to develop on a planet are as follows

1. Distance from the parent Star. The planet in question has to be in more or less the same orbit as Earth is from our Sun.
2. The Star itself has to be similar to our Sun. A bigger sun does not last long enough and a smaller one will not be radiant enough for life to develop.
3. Presence of water. Water is known to be a pre-cursor for life.
4. Presence of Carbon, hydrogen and Nitrogen which form complex molecules.

see Article Origin of Life, and the work of Stanley Miller. Artoftransformation 09:14, 31 October 2005 (UTC)

The Question is, if the precursors of life are the same, shouldn't Life on other planets also take the same form that we have taken? Won't other planets also evolve bacteria, fungi, plants, animals and should I dare say Intelligent beings who may look so much like us?
-WarrKay 03:31, 19-Oct-2005(IST)

• Not entirely, the distance of a planet can differ, provided the star's radiance fits the position of the planet. Also, the conditions for Planetary habitability are based on what we know. It's quite possible there's life that fits other conditions, but our current scientific knowledge can't prove anything about that either way. - 131.211.50.198 09:56, 19 October 2005 (UTC)

Nobody knows, but life on earth is so diverse it suggests life could be very diverse elsewhere. Among the most intelligent animals on earth are dolphins, dogs, and octopi, which don't look anything like us. Shantavira 09:59, 19 October 2005 (UTC)

• Re intelligent dolphins, see Hitchhiker's Guide to the Galaxy. ;) Don Diego 10:02, 19 October 2005 (UTC)

A lot of things in this universe depend on chance. It was only because of our solar system's unique arrangement that life was able to develop here. If life on other planets were to develop in exactly the same way, i.e. following our evolutionary process, the planets would more or less have to be arranged in the same way as ours, and then the timeline has to be the same, etc. Life could evolve also without these precursors. National Geographic produced a series called Extraterrestrial, wherein scientists speculated about the evolution of life on other planets, for example on a gas giant's moon, surrounding a red dwarf, etc. The parameters were changng constantly, and the show itself was very interesting. Don Diego 10:01, 19 October 2005 (UTC)

One of the important points of evolution is that it is random. Microbes may well be very similar to our Earth ones, but as life evolves further, more differences would emerge. For example, eyes are considered to have started as a random mutation which caused a light sensitive patch of cells. If early beings did not get this mutation, then the entire natural history of the planet would be very different. smurrayinchester^{(User), (Talk)} 10:03, 19 October 2005 (UTC)

Although light sensitive cells, which eventually lead to the evolution of eyes, are so advantagious that when they do randomly develop they tend to stick around. Which is why the eye has seemingly evolved independently many times. See convergent evolution --Majts 02:53, 20 October 2005 (UTC)

Life can exist in a much broader range of environments than we're usually taught in secondary school biology; see extremophile. And those are just organisms evolved on earth. The evolution of life on Earth itself was not terribly predictable and involved a great deal of chance- there's a book about this by Stephen Jay Gould called Full House.--Pharos 10:13, 19 October 2005 (UTC)

Organisms could even develop resistance to UV-rays if they were situated on a planet orbiting a dwarf star. But then again, it depends on the heavenly lottery, where life is going to evolve. Intelligent life, on the other hand, could already possibly exist, although either they are to shy to communicate with us, have tried to remove all traces of their existence so as not to be bothered by stubborn Earthlings, or have not yet developed the technology to communicate with other alien beings. If intelligent life other than our own races existed, I'd dare say that they don't want (or need) visitors from beyond. Don Diego 10:18, 19 October 2005 (UTC)

No, it won't take the same form, for the same reasons the dolphins can't mate with sharks. Even on earth, the role of chance in evolution is overwhelming, and even where organisms of different origins have evolved similar traits to fit similar ecological niches, they are still very radically different. Alien organisms should be even more different. I think this is one of the stronger arguments against the existence of intelligent alien life – I think that it is as wrong to imagine aliens being intelligent in the way humans are as it is to imagine sharks to act like dolphins, and I have yet to see a convincing definition of intelligence that doesn't boil down too "seems to be like humans". --Diderot 10:53, 19 October 2005 (UTC)

I would say dolphins are rather similar to sharks (at least the smaller sharks that eat fish). They have similar skin and fins, no hair or fur or feathers, no visible ears, etc. These similarities are remarkable considering how different the evolutionary paths are that led to those creatures. Another example of parallel evolution is bees and hummingbirds, which both independently devloped the ability to hover in flight in order to feed off flowers. StuRat 23:08, 21 October 2005 (UTC)

I assume that we are talking about life as we know it....Capitan. :-) --Eye 22:15, 19 October 2005 (UTC)

There are some interesting speculations about additional conditions for life at the Fermi paradox article. --JWSchmidt 00:08, 20 October 2005 (UTC)

Who says life can't be silicon-based? --65.188.159.140 02:57, 20 October 2005 (UTC)

• Of course, even most mainstream scientists will admit that there's no evidence of any life sustaining planets, anywhere else in the galaxy, and that man is most likely a unique creation--WwJd 04:20, 20 October 2005 (UTC)

• Keep in mind, "life" is only a word; a literal metaphor used to express an idea. This would require us to define what life is. Some suggest fire is alive. It is born in a sense, and it dies in a sense. Fire consumes, and it also reproduces. In this case, if we are to suppose that our definition of life must in some way or another involve DNA, then yes, there are very specific requirements (carbon, oxygen, nitrogen, and hydrogen, as well as a number of other spacial requirements), but as suggested above, why can life not be silicon based? Or an as yet to be discovered form? What I'm getting too is that with this perspective in mind, the universe itself can be seen as alive, and we (being carbon-based lifeforms) are only one of a potentially countless array of possible configurations. - Cobra Ky (talk, contribs) 04:55, 20 October 2005 (UTC)

Might I suggest an article to open your minds?

• Alternative biochemistry- Cobra Ky (talk, contribs) 04:36, 20 October 2005 (UTC)

The idea that everything is alive sits well with me even if it is only in the spritual sense. --Eye 22:06, 20 October 2005 (UTC)

Life exists many places on our planet where we humans cannot, although perhaps not sentient life.

• North and South Poles
• Bottom of Ocean
• Inside caves and caverns where there is never any light
• Underground (what do worms eat?)
• High in our atmosphere
  • Around Hot gas vents called Black Smokers
  • Around Hot water springs Mud Pots Artoftransformation 09:14, 31 October 2005 (UTC)

Consider a system with 2 or more stars orbiting each other, or a black hole, or whatever, there's enough radiation there for planets to be further away and sustain life.

Our moon is humogous relative to our planet by average standards, so we evolved with significant tides, very rare as averages in our known universe goes, although telescopes not yet telling us a whole lot about planets around other stars. How come our moon is so large? Well I buy the arguement that once upon a time there was a planet between Mars and Jupiter that broke apart, and a lot of the pieces did not stay where the asteroid belt now is, they flew outwards and inwards, and some were captured by gravity of other planets, one of which being our moon. I recognize that is not the most popular theory of astronomy.

Meteors have been found with fossils inside. How did they get there? Most plausible to me is that when our planet was hit with a really large rock from space that made a crater like Hudson's Bay in Canada, the rock that killed off the dinosaurs, etc. that some of our planet splashed into space, and those chunks of rock had life that became fossilized, but there is an argument, that I cannot follow, that says some of that came from Mars. Assuming these rocks carry simple life that can come off them and thrive again, when given moisture and light, then contamination can travel from planet to planet. AlMac|^(talk) 01:33, 26 October 2005 (UTC)

See Drakes Equation Artoftransformation 09:14, 31 October 2005 (UTC)

Brain hyperactivity

Throughout my entire life, I had a problem with "thinking". I always thought way too much about things, all sorts. I can't control it at all, and in several occasions I got headaches and sick because of it. It's physically PAINFUL sometimes (I get tense and my throat, face, neck and guts hurt). I've tried learning relaxation techniques and all, seen psychologists, and even got to a few doctors who offered me some medication (fluoxetine). It didn't work. Recently I had an issue with a friend, partially because of this. I, of course, am feeling terrible about it. The problem is, this led to a major impulse in this thinking pace, and I can barely sleep now. I'm hardly hungry (but I got more thirsty for some reason). And this all scares me. I'm beginning to think there's something neurological behind this. So I set an appointment with a neurologist. I'm not sure if this is the best thing to do, but can't be any harm, eh?

My question is this: are there any sort of neurological conditions that cause this sort of problems? If so, what sort of medical solutions can be taken? If not, what could I possibly do, I've ran out of ideas here.

Attention-deficit hyperactivity disorder, Obsessive-compulsive disorder, and Amphetamine use come to mind. (I'm not a doctor -- you should wait to see your neurologist before jumping to any conclusions.) --Quasipalm 14:28, 19 October 2005 (UTC)

OCD, perhaps, but the rest? I don't think so. I don't have problems with ADHD, I can focus on things and everything, I just can't control thinking about everything else while I'm at it at the same time. This is what bothers me.

Have you considered meditation? Also I can't help wondering whether you need to get more exercise. Your diet might also be a factor. Shantavira 19:10, 19 October 2005 (UTC)

Yes I have, along with the relaxation and all... Tried it 15 minutes/day for about a month, and I just couldn't stop these "streams". Also, this triggered some sort of double personality, so I started arguing with myself, inside my head, while I was with this. It's like some other part of me was trying to disturb me. Now, excercise and diet seem more likely to be an issue. I'm very sedentary and my diet is poor (i'm underweight and my diet is not very rich, indeed)...

Proper diet and exercise might well be the cure. Even if they aren't, getting healthier can't exactly hurt, can it ? I particularly think the balance of electrolytes is critical. I have noticed I get muscle spasms when I haven't eaten well, maybe it affects your brain. If, and only if, proper diet and exercise fail to fix the problem, should you consider going to psychoactive meds. They could mess you up, so don't risk it unless you've used up all other options. StuRat 22:57, 21 October 2005 (UTC)

The symptoms you describe could means lots of things, including a little bit too much anxiety and self-analysis. None of us have any business diagnosing you with anything definite. However, I will offer guidance to the right kind of doctor. Your symptoms undoubtedly fall on the mind side of the old cartesian mind:brain divide. Whether you need reassurance and insight, constructive suggestions, or diagnosis and treatment, you will get more help, more sympathy for the symptoms, and a more experienced perspective from a mind doctor than a brain doctor. I promise I am saving you a step. Good luck. alteripse 23:09, 19 October 2005 (UTC)

Yes, but I've seen psychologists and they all said the same thing: that I had some self-esteem issue so I was constantly judging myself, and that I'm too anxious with things, so I judge them too often. They sent me to this other guy who gave me the fluoxetine, which, like I have stated, didn't help. BTW, I'm 19.

That is very frequent. Many people have struggles and misunderstandings when they are young. To be 19 and experience difficult thoughts is common, but to feel tense and unsure and self-introspecting isn't so good. There are many things going on at this time in your life. You are probably finishing puberty, finding friends/relationships, maybe you are in college or working in a new place and feel self-inefficacy because others are making things tough for you as a new guy. If you are moving onto something new or having struggles with your family as a growing adult, that can lead to feelings of insecurity. The same if a death or loss of a loved one occurs. You might be undergoing higher education and feeling unsure of yourself because of academics. Maybe you are struggling with a crisis of faith or are coming to truth with something you might have overlooked or are not addressing in your life. Maybe you are having troubles with your relationships and are feeling lonesome, now introspecting, thinking "What is wrong with me? Why is all this happening?" If it is a long-term group of thoughts, I feel you are tinging on a few thoughts or a new schema of the world that you can't quite solve. If you have been having these feelings all along, you may be an only child or have a "different family" or have had an alienating lifestyle or childhood that is leading to your discomfort now. Since you had an "issue" with a friend recently about your thoughts, you may be very disconnected socially from others because of something, and by continuously introspecting to figure out what the "issue" was, you are continuing this problem and bringing on more "issues" and further thoughts, until neither the outside "issues" nor the inner thoughts resolve themselves. Of course, we can't know what happened to you in your life that may have made these impulsive thoughts come along, but if they are long-lasting, it may be some long-term relationships or struggles that you are going through. I strongly recommend you see a psychologist. Drugs are an alternative, but I can see from your eagerness to discuss this on the internet (of all places) that you most likely need a person to talk this through and solve this conundrum. Good luck in your endeavors.--Screwball23 21:47, 1 November 2005 (UTC)

I would be careful. I was diagnosed with OCD and put on medication. Nothing worked. I had 4 different kinds over 4 years. By then I was a wreck. Finally I found out I did not have OCD. It has taken me years to recover. If the problem is just thinking, then that is not really a problem. If the problem is thinking about the same things over and over without any resolution, that is an anxiety disorder. You are probably very smart and like to think about things, like quantum physics. Arguing with yourself might just be a very pronounced way of resolving inner issues, trying to make decisions. Alteripse is right, though, when saying none of us has any business diagnosing you by 'remote control' this way. Find a good counsellor and get some help, it may be you just have an active imagination. Top priority is to find a counsellor you trust.

I have a similar problem, though nowhere near as serious. I just can't get to sleep because I'm constantly thinking of things. A 'solution' that has worked for me for 25 years is to smoke some marijuana before sleeping. Just a bit works wonders. A big advantage is that if it doesn't help it won't hurt any either. A potential major problem is that it can land you in prison in many countries (I have the good fortune to live in the Netherlands). Although even in the US it's accepted as a legal drug these days, I believe. You'd just need a doctor to prescribe it to you. DirkvdM 15:07, 24 October 2005 (UTC)

The body is designed to breathe, move (exersize), eat, excrete, socialize and have sex. Your brain will continue to nag you until you give it what it wants. Stop repressing yourself. WAS 4.250 00:58, 26 October 2005 (UTC)

Define gravitation

Please remember to search before asking questions; see our article on gravitation.

Take a look at gravitation. — Laura Scudder | Talk 16:36, 19 October 2005 (UTC)

It's also a huuuuge book by John Wheeler, but Laura's link will probably be more helpful. -- SCZenz 16:39, 19 October 2005 (UTC)

Basic binary sum circuit

I had to create a basic binary sum circuit for my computing class, where three single-digit inputs would be summed to obtain two outputs, one for each digit of the sum (e.g.: if I had 1, 1 and 1 as input, I would get 1 and 1 as output; if I had 1, 1 and 0 I would get 0 and 1, and so on). I can do the first digit no problem – (A xor b) xor C – but I'm having some trouble doing the second digit. So far I have succeded in summing the first two inputs – A and B – but I don't know how to sum the third. Any help? :) Sorry if this explaination is somewhat incoherent, but English is not my native language -- Whitetigah 16:39, 19 October 2005 (UTC)

Try looking at the adder article. --cesarb 16:49, 19 October 2005 (UTC)

Thank you, that was exactly what I was looking for :) -- Whitetigah 17:41, 19 October 2005 (UTC)

astrophysics

why are almost all planets in the solar system coplanar i.e all their orbits lie on a single plane?is it specific only tothe solar system or is it found in other planetery systems?

They are not exactly coplanar. You may read the Protoplanetary disc article for some insight. There is also the issue of outer planets acting like large vaccuums, and removing smaller planetoids, and other bodies with odd orbits. Dominick ^(ŤαĿĶ) 17:13, 19 October 2005 (UTC)

You might be interested in the discussion on this question elsewhere at the Ref Desk. Note that Pluto's radical inclination is widely believed to result from Pluto's post-creation capture as opposed to the co-formation of the other planets. 199.209.144.218 17:28, 19 October 2005 (UTC)

Sand bags

Considering the relatively higher permeability of sand compared to clay, shouldn't we ideally be using "clay bags" rather than "sand bags" in a flood?--Commander Keane 17:46, 19 October 2005 (UTC)

• My guess, which is only my guess, is that clay is a lot harder to move around than sand. --jpgordon∇∆∇∆ 18:02, 19 October 2005 (UTC)

Sand can be removed later, clay sets and sits in one place. Sandbags collect garbage from the floodwaters and do a surprizingly good job at damming a flood, from my personal FL experience. (Turn Wilma turn!) Dominick ^(ŤαĿĶ) 18:08, 19 October 2005 (UTC)

That's the great thing about sandbags: even if some water gets through the sand it's clean, so you just have water damage, rather than mud/gunk everywhere on top of water damage. I'd also think that the fact that sandbags naturally reshape themselves to fit their neighbors is a big advantage over clay. — Laura Scudder | Talk 18:35, 19 October 2005 (UTC)

Sandbags are particularly useful as secondary supports. An unsupported concrete wall can easily be pushed over in a flood, due to the pressure differential between water on one side and air on the other. If sandbags are piled up against the air side, that will substantially eliminate the pressure differential and prevent collapse. StuRat 22:46, 21 October 2005 (UTC)

A few questions about Hybrid vehicles like Prius

I have a few questions about hybrid vehicles like Toyota Prius. What I want to know is- 1) How much more hybrid vehicles like Prius cost (in %) more than gasoline powered vehicles with similar power and capacity? 2) How many times mileage does Prius or other hybrid vehicles give compared to similar gasoline vehicles? 3) Should we charge the battery that runs the car similar to electric cars? 4) Are all hybrid vehicles automatic geared?

Many of your questions can be answered at hybrid vehicle, or by surfing the web sites of car manufacturers. But here's some quick and dirty answers:

1. According to Toyota's web site, the Prius starts at US$21,275, whereas the Matrix, which seems to be of a similar size, starts at $15,110. So it's about 35% more expensive. But I'd bet you'd make up the cost in gas savings fairly quickly.
2. Toyota's site says the Matrix gets up to 30 city MPG, whereas the Prius gets 60 city MPG. Of course, numbers straight from the company like this are always wishful thinking…
3. No. The battery is actually charged by the gas engine.
4. That one I'm not sure of.

Garrett Albright 18:51, 19 October 2005 (UTC)

RE: #3 -- Some people have actually hacked their cars to be able to plug them in overnight at home. See here. They reported that the Prius was able "to reach between 100 and 180 MPG in a typical commute" after the change. So, why don't hybrid cars ship with the ability to plug-in? Reportedly, because car companies were so afraid that people would think that cars that plug in would be annoying or weak, they didn't even build them with the option. Dumb, eh?

RE: #4 -- The Honda Insight has a manual / hybrid version.

--Quasipalm 19:06, 19 October 2005 (UTC)

The matrix is significantly larger than the Prius, the Prius is more similar in size to the Echo. A better comparison would be the Honda Civic ($14,650) vs. the Honda Civic Hybrid ($21,850), that's a 50% difference in price and averages 15mpg better. That means at 10000 miles/year and gas at $3/gal, The Civic would use 285 gallons of gas a year and the Hybrid would use 200 gallons of gas a year. That means you save a whopping $255 a year, which means you would have to own the hybrid for over 28 YEARS for you to come out ahead. Despite the manufacturer's marketting, Hybrids are still nowhere CLOSE to economically feasible. Even with gas at $5 a gallon, it would take almost 17 years, with gas at an absurd $10/gallon, it would take 8 and a half years. -Drdisque 22:21, 19 October 2005 (UTC)

Here's a great site, Garrett, fueleconomy.gov. --Quasipalm 23:15, 19 October 2005 (UTC)

In the United States, recent regulations raise the prices of hybrids artificially high. To save money, buy a large SUV for "personal business use"; I believe you can get a $3,000 rebate from the feds for this. (My Republican-voting boss cashed in on this GW Bush gas-guzzler govt. hand-out; bragged about it for months. I tried to shame him by saying "welfare mom" and "food stamps" but he flipped me off. I quit a few months later.). However, it has to be a truck or SUV, the rebate does not apply to ordinary-sized cars that Democrats drive. Write to your senator if you think this is wrong... linas 05:14, 1 November 2005 (UTC)

Avian influenza

Is VIRA 38 snake oil or actually capable of reducing the risk of catching avian influenza should it begin to spread amongst humans? Also, is Tamiflu available anywhere via mail-order without a prescription? I'm not freaking out or anything, but Science Friday freaked me out a little last week. (Perhaps it's a good time to re-read The Stand ;-) --Quasipalm 18:56, 19 October 2005 (UTC)

I'm having trouble finding published research on "VIRA 38". As far as I know, the neuraminidase inhibitors such as Tamiflu have only been tested in short-term experiments. It is not clear to me that they are the solution to a flu pandemic. The idea that the world should stock pile these drugs in order to limit a pandemic seems to be a good way for a few drug companies to make a lot of money. It may be that the money would be better spent on ways to limit exposure of humans to the avian flu virus and development of vaccines. --JWSchmidt 23:53, 19 October 2005 (UTC)

A vaccine cannot be developed until the virus mutates into a form that can cause the pandemic. There is a delay of 4 – 6 month before enough vaccine can be produced. So the idea is, that antivirals will reduce the death toll in the meantime. Theresa Knott (a tenth stroke) 23:57, 19 October 2005 (UTC)

A human vaccine for the avian flu virus has already been reported ("AVIAN INFLUENZA: 'Pandemic Vaccine' Appears to Protect Only at High Doses" by Martin Enserink was in Science, Vol 309, Issue 5737, 996 , 12 August 2005 doi:10.1126/science.309.5737.996b). If actions (such as vaccination) were taken to protect against infection of humans by existing avian flu virus, then there would be a reduced chance of a mutant form evolving that would easily transfer between humans. There can be some protection from antibodies to a type of flu (like H5N1), even if the antibodies are made against a different variant of the type. If humans were vaccinated against the existing H5N1 type bird flu, there would be some protective antibodies that would cross-react with new mutant strains. I'm not saying that the neuraminidase inhibitors are useless, but I'm not sure that they are the best way to throw money at the problem, particularly if it just turns into a matter of those few who can afford the inhibitors getting them via mail-order. --JWSchmidt 00:33, 20 October 2005 (UTC)

Pulseless Electrical Activity PEA (EMD)

Hello, I hope you can help with this enquiry, I am currently on a medical course and have just failed a practical assesment. I was following the protocol as I understood it in that I shocked my PVT patient four times until their rhythm changed. What I saw was a sinus rhythm and checked the carotid pulse and was told that there was a weak palpable pulse. I interprited this as sinus rhythm and gave AV for one minute and re analysed patient. On completion I was told that the patient had been in PEA and should have commenced CPR. Am I way off the mark or can you as was explained to me by the assessor a palpable carotid pulse in PEA?

Many thanks Alastair Palmer --62.189.84.170 18:57, 19 October 2005 (UTC)

A Google yielded our Pulse article, the baseline Emergency Medicine guideline to palpate for carotid pulse for 10 or more seconds as a preliminary for CPR, and some additional guidelines for performing immediate surgery. It looks like the technique is fundamental for physicians. But a further Google using the exact wording on your question also indicates this is a pre-terminal condition with a 5% survival rate, so it is unclear to me why CPR for PEA (EMD) is more than a stopgap; a 3rd Google shows that the CPR responder should also be requesting Advanced cardiac life support (ACLS) at the same time. Thanks for posting the question. But the Google hits make me wonder whether the symptom lack of carotid pulse=>CPR is consistent with weak palpable pulse. What did the assessor mean by this? Ancheta Wis 10:31, 21 October 2005 (UTC)

Infinity

Many years ago I remember my maths teacher saying that mathematicians didnt use infinity in equations. Something to do with things not adding up. I was never interested in maths but that has always stuck in my head. Is this true? If it is true how then does science deal with infinity when the language of science is maths and infinity in terms of the universe is ..well .a distinct possibility.--Eye 22:12, 19 October 2005 (UTC)

You can't use infinity as some form of quantity, because when you try and do tricky things with it, things break down. Sure, inf + inf = inf, 2*inf = inf, but what is inf/inf? (Suppose inf/inf = a, then inf = a inf. You can choose any such a and the equation will still work). There are other cases like this.

However, infinity can be a useful symbolism. If you want to express the sum 1/2+1/4+1/8+..., you can write it as

$\sum _{i=1}^{\infty }{1 \over 2^{i}}$

but really, this is the same as saying

$\lim _{n\rightarrow \infty }\sum _{i=1}^{n}{1 \over 2^{i}}$

where the "lim" means the limit as you let n get larger and larger.

So infinity is more like a concept than a quantity. Lots seem to get entranced by the idea of infinity, so you should get a large response here... Dysprosia 22:35, 19 October 2005 (UTC)

(Added after edit-conflict so might be parroting Dysprosia a bit).

The thing with infinity is that it really makes no sense. Take for instance the classical example of divison by zero. Lets try dividing 5 by zero:

${\frac {5}{0}}=\infty$

Ok, so far, so good. Well, that must mean.....

${\frac {5}{\infty }}=0$

Sure, sure, ok, good.....

${\frac {5*\infty }{\infty }}=0*\infty$

Hmm, where are you going????

$5=\infty *0$

What???? Infinity times zero equals 5!!! Cool!! Anyway, the point is, when you treat infinity like a normal number (ie you put it in formulas and subject it too normal algebraic operations like cancelling out factors from a divison), ridiculus stuff happens. When math has to deal with infinity (and infinitismals), such as in calculus we replace them with limits. A limit is basically a number that goes "very, very close" to a certain point (such as infinity or zero). For instance, to find the derivative of the function x^2 (if you don't know what a derivative is, don't worry, it doesn't really matter) you have to simplify this equation:

${\frac {x^{2}-(x+h)^{2}}{h}}$

Where h is a number that is an infinitismal (ie an "infinitly small number", a number as small as possible). Normally, this would break the division by zero-rule, but if we impose limits we can work with it.

$\lim _{h\to 0^{+}}{\frac {x^{2}-(x+h)^{2}}{h}}$

$\lim _{h\to 0^{+}}{\frac {x^{2}-(x^{2}+2hx+h^{2})}{h}}$

$\lim _{h\to 0^{+}}{\frac {2hx-h^{2}}{h}}$

$\lim _{h\to 0^{+}}{2x-h}$

Now, since h is so tiny that it really doesn't change the result anymore (since it's basically 0), we can safely remove it and the limit and get the answer, 2x. This is a bit (alot) simplified since you are a non-mathematician (so am I btw, I'm a serious dilettante), but that's the gist of it. gkhan 22:54, 19 October 2005 (UTC)

Mathematicians definitely do use infinity, although for reasons the above posters mention, you must use care, or you'll end up in trouble. There are in fact several different numbers which could be called infinity. There is the infinity in the extended real line, which satsifies a bunch of things like infinity + any number = infinity. The expression infinity*0 is left undefined (no one claims that infinity*0=5). Other infinities include omega and aleph nought, and many more. -Lethe | Talk 01:06, 20 October 2005 (UTC)

Of course any discussion of infinity (you have at least skimmed that article right?) would be lacking without a mention of cardinality of infinity. That is something that blows most peoples minds when they first learn of it because they are used to the conventional wisdom of infinity being the biggest thing out there. How could there possibly be different sizes of infinity? Well at least in set theory there is. - Taxman ^Talk 18:17, 20 October 2005 (UTC)

I think you people are deliberately trying to confuse me. :-) --Eye 20:14, 20 October 2005 (UTC)

If $1/\infty =0$ then one might assume that the infinity being referred to is countable. However, if one accepts the existence of countable infinity, then by set theory (see Cantor's diagonal argument), one must also accept the existence of uncountable infinity. If the reciprocal of countable infinity is zero, then surely the reciprocal of uncountable infinity is also zero? Of course. But then what is the reciprocal of zero? Is it countable or uncountable? It cannot be both, because if 1/0 is equal to both infinities, then the two infinites are equal to each other, which they are not, by definition. So paradoxes such as these blow up in one's face, and one must conclude that infinity is somewhat beyond ordinary grasp.

It depends on what field of numbers one is dealing with. The field of real numbers does not include infinity even though its cardinality is uncountable infinity. So when one asks "how many real numbers are there?" the answer is not a real number. Real numbers are good enough for practical purposes: infinities being dealt with as limits. However, it is possible to define other mathematical structures which include things which are called "infinities". For arithmetic, see surreal numbers. For geometry, see projective geometry.

Physics is based on the ability to take measurements of physical quantities, such as mass, distance, and time. When an experimental physicist makes a measurement, the instrument which makes the measurement is finite, and the number resulting from that measurement is finite. Physical theories are confirmed by being tied down to experiment (see empiricism) and physical experiments always give finite answers. Physics deals with infinities by getting rid of them, by hook or by crook: see regularization and renormalization.

Mathematics, on the other hand, is rationalistic and not empirical. Mathematical structures are tested by self-consistency: if it is not self-consistent, it does not exist. Each mathematical structure is self-contained and independent of other structures, so Euclidean geometry and Riemannian geometry each have their own separate existences, even though they would contradict each other. (Likewise, the theory of infinity has two branches, one which accepts the continuum hypothesis, another which rejects it: but each branch capable of being self-consistent.) Moreover, mathematical structures do not have physical existence. The number five does not physically exist. One might have five finger's on one's hand, but the five fingers are not the number five. One might draw a red number 5 on a paper, but that five is not the concept of number five. The symbol $\infty$ for infinity is not itself infinite. The symbols which mathematicians manipulate on paper are all finite. Infinites are known only indirectly, through logical inference, and inhabit a non-physical realm. So when one says "There are a countable infinity of natural numbers", those numbers do not really exist physically. Besides, if mathematics only dealt with infinities, it would be impractical and rather useless and mathematicians would not gain their bread, whose quantity is finite, positive, and non-zero, which they eat regularly in order to obtain a finite, positive, non-zero amount of energy (see pragmatism). On the other hand, mathematics does have a corner of its realm permanently reserved for infinities: as Hilbert said: "No one can drive us from the heaven which Cantor created for us." —Anonymous, 20 October 2005

What's infinity + -infinity? Jazz1979 10:58, 30 October 2005 (UTC)

+ (inverse )is a arthmatic operation, and might not be valid on non-numbers. The algebra of infinity is a subset of mathamatics called Non-Standard Analysis.

See this link: Types of Infinities to Summarize: infinity + a constant = infinity .: infinity + - infinity = a constant.

For a more precise definition: [[http://www.math.vanderbilt.edu/~schectex/courses/infinity.pdf%7C"Georg Canor (1845–1918): The man who tamed infinity." Artoftransformation 09:57, 31 October 2005 (UTC)

October 20

Computer science and math skills

I'd like to know just how skilled one would have to be at mathematics in order to go into the field of computer science. After reading some articles on the subject here on Wikpedia (which I could barely understand, if at all) it seems like a fascinating field. Impaciente 01:09, 20 October 2005 (UTC)

Computer science is broken into several branches, including computer engineering/architecture which requires some technical skills to learn what component functions are, computer programming, which is oriented towards learning languages and a form of qualitative logic that is needed to understand the workings of the code of the program, and then, computer networking and information technology, which is concerned with computer services and networks. In computer programming, generally very little math is required, but that is only in my experience. Pick out books or articles about certain regions of comp-sci and find your way through the subject.--Screwball23 02:02, 20 October 2005 (UTC)

My experience has been that computer science doesn't require a complex mathematical background. In completing my Bachelor's degree, I would have only encountered complicated mathematical formulas once or twice (in case you are wondering, Data Communications and a subject on Artificial Intelligence). Apart from these two instances, I think a sound knowledge of algebra and problem solving will probably get you through (bear in mind I am Australian, so maybe your education system is a bit different). Ranglin 02:56, 20 October 2005 (UTC)

However, if you want to become an computer science researcher, as distinct from a practising programmer/software engineer, mathematics skills become a lot more important. A friend of mine did a PhD in the computer science department at Princeton University; he didn't write a single computer program during that period. His work was entirely mathematical. Much of theoretical computer science is essentially a branch of discrete mathematics, there may be a lot of statistics in some areas, and many topic areas (such as computer vision) require a fair bit of mathematics.

In any case, while higher mathematics may not be strictly necessary to become a computer programmer, the mindset that it teaches you is a very valuable skill in becoming a good one. Maths is good for you :)--Robert Merkel 03:08, 20 October 2005 (UTC)

While this is generally true, it is possibly to get even a PhD in CS if you are not so good at math (although it is hard in practice). There are some areas within CS that require less math, notably systems. Having said this, it really really helps if you are good at math. First, because fundamentally programming is logic (i.e. math), and you have to be good at programming to get a CS degree. There are, however, people who are bad at math and good at programming, although this is not common. Second, to be a good programmer, you really need to understand certain concepts which are mathematical in nature (e.g. computational complexity). One thing to remember is that the kind of math one needs for CS is different from the sort of math one is used to in high school or math college courses. In particular, calculus is not especially important. Ornil 05:05, 20 October 2005 (UTC)

I first went to university hoping to score a degree in computer science. However, my high school had an experimental math program known as College Preparatory Mathematics that sure as hell didn't prepare me for college math, and I scraped by with a D- in pre-calculus, a class that didn't count toward the degree anyway. I gave up and switched to English literature. However, I know how to program; I've been writing programs of various degrees of complexity since I was twelve or so, and the most complex thing I've run into is parabolic equations. So really, even though higher math isn't seen so much in programming in the real world, you do need to have a knack for math to get a degree in computer science. Garrett Albright 14:04, 20 October 2005 (UTC)

I'm an application programmer speciallizing in CAD and database apps. While I have used advanced math up to calculus in some of the applications (calculating component masses for center of gravity analysis), this is just my case, not typical. I would say a typically programmer won't have to deal with more than basic math, perhaps time math and percentages being the limit (used for benchmarking how much faster one version of a program is than another). Knowing how to extrapolate a graph is also quite useful..."If the program can process 10 items in one second and 100 items in ten seconds, it should take how long to process 1000 items ?". If you work with graphics, some knowledge of geometry is also needed, such as the formulae for distance and a circle. StuRat 22:22, 21 October 2005 (UTC)

I majored in math in college because it was my favorite and best subject in high school, then discovered to my dismay that college math is a totally different subject than high school math, then was pleased to discover that college physics is very similar to high school math, so I switched majors. Out of college, I discovered that what I had learned in college had no correlation with what the job market was looking for, talk about not planning ahead, but most everyone that way. I went into computing because of an illusion that there was some relationship between computers and math, and found that from perspective of the end user, and the worker in the field, computers have as much to to with knowing math, as driving an auto has to do with knowing how the auto works inside the engine. About the only mathematical stuff I have needed in a multi-decade computer career has been decent estimating skills. I mean write a program to get certain answers. How do you know it is getting right answers? How do you know you not have a rounding error? Well in my brain I can get ball park answers to compare with computer answers. AlMac|^(talk) 01:44, 26 October 2005 (UTC)

Excel column headings

I'm using Excel 2003. Every worksheet comes up with numeric headings at the top of columns. How can I change this to alphabetical headings? I've searched the Excel section of the Microsoft Office 2003 All In One manual but without finding a solution. I have a feeling I'm missing something pretty basic, but what?

Erasmus 02:12, 20 October 2005 (UTC)

Go to Tools/Options/General and deselect "R1C1 reference style".-gadfium 02:48, 20 October 2005 (UTC)

Thanks, Gadfium, it works beautifully. You've saved me hours of thrashing around. Erasmus.

Who manufactures the buses of the so-called "Wiki Wiki" shuttle line at Honolulu International Airport?

The buses are owned by the State of Hawaii and operated by Airport Group International. Who is the manufacturer?

Example photo: http://www.futureofthebook.org/blog/archives/wikiwikibus.jpg .

I don't recognise the badge logo, and the picture is too low-resolution to zoom in and tell that way.

Why not contact the operators and ask? --Robert Merkel 03:32, 20 October 2005 (UTC)

What are the interrelationships between science and technology?

What are the interrelationships between science and technology?

Our Technology article states: "The lines between science and technology are not always clear. Generally, science is the reasoned investigation or study of nature, aimed at finding out the truth, generally according to the scientific method. Technology is the application of knowledge (scientific, engineering, and/or otherwise) to achieve a practical result (Roussel, et.al.)." Capitalistroadster 08:09, 20 October 2005 (UTC)

• It's a very big and complex question. Scientists create technology in order to do science (think of Galileo and the telescope), but it is also often a case of a solution looking for a problem (nobody was enthusiastic about PCR when it was invented, for example, because they were worried about different problems than the one it would eventually solve). Sometimes technologies in a broader sense are derived from scientific understanding (the nuclear reactor from nuclear fission, for example), though the conversion is in no means usually simple ("reduction to practice" is often quite difficult, because no technology is reliant on elementary scientific notions alone). On the other hand, there are technologies which were created without any reference to scientific knowledge — in many cases the technology comes first and is understood by the science later.
• In short, they are very interrelated activities, and the forms of causality (what causes what) goes both ways at different times, and at times they have nothing to do with each other at all. Hopefully that answer gives you some food for thought. If you want to read an interesting book about the relationship between invention and science, I recommend Thomas Hughes, American Genesis: A Century of Invention and Enthusiasm. --Fastfission 16:54, 20 October 2005 (UTC)

CCE

What does "CCE" in various Atari 2600 games stand for? (some exposition or exhibition?) Thanks.

CCE was the (unlicensed) company that used to sell some Atari 2600 games and other stuff here in Brazil (and apparently in the rest of South America too). I suppose that ROMs with the CCE text were ripped from Brazilian\South American cartridges. EDIT: take a look at this page I found too ☢ Ҡieff | Talk 06:00, 20 October 2005 (UTC)

On another note, the company still exists and its products are worthless than junk. ☢ Ҡieff | Talk 07:43, 20 October 2005 (UTC)

Opening Matlab

I currently have Matlab installed on my computer. But when I open the program it gets to the initalising stage and then closes again. So far I have tried reinstalling windows and also resinstalling the service packs. But it still wont work. Does anyone have any ideas on the cause or solution to this problem, would be of great assistance.

• I don't use Matlab myself, so I'm probably of little help in that regard, but I'd like to tell you to be careful about reinstalling Windows. It may break settings you've had or if there's a problem, kill your computer altogether. Only try reinstalling Windows as a last resort in the future. - 131.211.51.34 07:22, 20 October 2005 (UTC)
  • Matlab seems to do a lot of thing on startup, so a diagnosis will be interesting. It may check to see how many concurrent licences are running on the network etc. Try searching Mathworks support for some help. I dug up Problems Starting Matlab which might be of some use. Good luck!--Commander Keane 11:16, 20 October 2005 (UTC)

Breakdown of a trillion dollars in ways people can easily understand.

Hello, all. I have a question/favor to ask. This question may be in a wrong column for asking, but here it is. Long time ago, I saw in a newspaper with a columnist showing and explaining just how much a trillion dollar is, in a sense of talking about national debt, and to make it easier for everyday folks to understand, there was a breakdown of a trillion dollars on this column. A broad general example would be that a trillion dollars is enough money to buy 30 NFL football stadiums, 100 3-carat diamond rings, 100 Corvettes, and still have a lot of money to buy or do other things. For some reason, a columnist's name Dave Barry comes to mind. I may be totally wrong on who this columnist was back then, but if anyone out there has any positive feedback or information or the article on it, I would really appreciate the information. Thanks.

Porc

Which trillion you're talking about? I don't know which is used in USA. ☢ Ҡieff | Talk 07:53, 20 October 2005 (UTC)

It would be the US trillion, as the British trillion is far more money than exists on Earth. StuRat 22:03, 21 October 2005 (UTC)

• According to Wordnet on answers.com, the US usage is one followed by 12 zeros see [50]. Everywhere else, it is one followed by 18 zeros. As to your question, I don't know but Dave Barry sounds plausible see [51]. Capitalistroadster 08:18, 20 October 2005 (UTC)

Everywhere else is not true. ☢ Ҡieff | Talk 09:22, 20 October 2005 (UTC)

Not to miss the point, but that sounds like kind of a crappy explanation of a trillion (american i guess) dollars. By my count, you could buy 97 $10B stadiums, 100,000 $200k Ferrari F1 Spiders, and 100,000 5 carat diamond rings (for $80k ea.), and still have money ($2 billion dollars) left. You know, for what its worth. (edited for more casual numbers). --Jmeden2000 21:45, 20 October 2005 (UTC)

I do remember a picture-based representation of how big a stack of bills you would need to represent a certain very large amount in cash, but I don't remember where I saw it (it was very impressive though). But I found this via a quick search (see second paragraph). Tzarius 10:03, 21 October 2005 (UTC)

A trillion dollars is enough to give everyone on Earth a color TV. WAS 4.250 01:10, 26 October 2005 (UTC)

"Unit" means "Mols"?

Hi all, a quick question. I'm doing some calculations on drug dosage, and I often come across statements like "This formulation contains 10 units of Pitocin per mL". My question is, when they say "units", do they mean "Mols"? Or is it some arbitrary unit that they've come up with? I suspect they do mean "Mols" (or "Moles"), but I want to be sure, and I can't find anything on Google. Can anyone help? For an example of the usage I'm referring to, see[52]--inks^T 09:16, 20 October 2005 (UTC)

• I'm not sure if it matters. Just ensure that your final answers are in terms of units e.g. "he should be fed 5 units every 24 hours." Charlie123 (Talk) 10:09, 20 October 2005 (UTC)

The use of 'units' or 'international units' for pharmaceuticals is in many ways a relic of the age before really high quality analytical chemistry. For a given drug or preparation, one 'unit' was the quantity of drug that produced a specific biological effect. (One unit of antibiotic X would inhibit the growth of a specific number of bacteria, for example.)

By measuring the potency of a drug through a biological effect, manufacturers didn't have to know the concentration of active ingredient (if the active ingredient was known), the concentration of different enantiomers, or the effect of different related active molecules. They just had to test each batch for biological potency and then slap a label on the jar. There's no specific conversion factor to go from 'units' to 'milligrams'; since international units are defined in terms of a biological effect, the conversion factor is different for each drug. (You can look up the conversion factor for most drugs, however.)

Now that we've gotten better at pharmaceutical chemistry, we can do two things that are gradually making measurement in 'units' obsolete:

1. We can produce very pure drugs with a single active chemical ingredient, and
2. We can measure the amount of active ingredient very precisely.

Hope that helps. TenOfAllTrades(talk) 11:49, 20 October 2005 (UTC)

• Have a look at International unit -- Rune Welsh | ταλκ | Esperanza 14:32, 23 October 2005 (UTC)

• According to Goodman and Gilman's textbook, the potency of Pitocin was originally determined by its ability to cause changes in vascular smooth muscle contraction. One unit is about 2 micrograms of oxytocin. --JWSchmidt 03:12, 24 October 2005 (UTC)

Computer upgrade

We have a set of pentium 20 computers and we would like to upgrade all our computers to pentium 4 confuguration.We had been suggested to upgrade the same by using a node concept which means to insert a card for each computer in a common server ,from where all the computers would be upgraded. We would like to have your opinion for the same.

By

shubhada

(formatting fixed --David Wahler (talk) 13:09, 20 October 2005 (UTC))

What are you trying to upgrade? Disk space? -- Ec5618 13:13, 20 October 2005 (UTC)

Maybe he wants a network-boot (PXE) setup? Tzarius 09:53, 21 October 2005 (UTC)

Instead of a single server, perhaps 2 servers would be better, allowing you to backup half at a time and still keep the others operational, for example. Also, if one server goes down you would still have half of your computers able to communicate with one another. StuRat 21:58, 21 October 2005 (UTC)

This is a Brilliant solution for some types of networks Artoftransformation 10:03, 31 October 2005 (UTC)

It depends completely on the current and planned usage of the computers. If your doing websurfing ONLY, then this might work, but you'll need a fast server.Artoftransformation 10:03, 31 October 2005 (UTC)

Similar Question: Id like to paint a small room, but faster than Michelangelo(11+ Years), but with higher quality? I dont mean to demean your question, but more information is definatly needed.

Liquid Leaking out of my hard disk

I have a clear liquid leaking out of an external hard disk – any ideas what it could be? Oil for the motor perhaps?After a shave 15:42, 20 October 2005 (UTC)

What ever it is, you should back up all the data off the disk pronto! Wierd behavior from disks is a sign of imminent failure. smurrayinchester^{(User), (Talk)} 17:02, 20 October 2005 (UTC)

Are you sure it wasn't fluid that once leaked INTO the disk enclosure making its escape? Most new drives are using fluid dynamic (oil-packed) bearings but i always thought the amount of fluid was trivial and wouldnt be enough to 'leak out' anywhere if it were compromised. See Fluid bearing for more info. Is the drive behaving in any abnormal way like overheating, noise, vibration, etc? --Jmeden2000 20:23, 20 October 2005 (UTC)

Those are bits leaking out! Danger! --jpgordon∇∆∇∆ 22:55, 20 October 2005 (UTC)

Maybe the hard disk watched too much TV, or played too many games, and now its brains are turning to mush. ;) Don Diego 11:51, 21 October 2005 (UTC)

Thanks guys. The disk has gone to heaven. It was making a grinding noise before death. All data is backed up tho... I have taken it apart, and I am quite sure that no liquid got in. Ah well After a shave 15:09, 21 October 2005 (UTC) :*Obviously it means your hardrive is too wet, you should try putting in a dryer, I hear strong electromagnetic fields are good for hard drives and other data storage devices--4.237.23.16 18:26, 22 October 2005 (UTC) Stupidty stricken out. Proto t c 12:18, 28 October 2005 (UTC)

How much virtual space exists in persistent worlds?

I am curious what a reasonable estimate of virual space might be in persistent worlds, such as MMORPGs. In particular, how does this amount of terrain compare with the earth.

Considerations, (please modify if so inclined)

• Equate the most common form of transport with driving a car at ~50mph.
• Estimate with and without duplicate shards or instances
• Estimate with and without non-persistent worlds, whatever persistent world is defined as...

Take it and run.. I'm not an active player on any MMORPGs at the moment, but would consider including even worlds such as LambdaMOO. My idea of space that qualifies is any electronically-provided 3D space a live individual is navigating simultaneously with other live individuals. (No, bots are not alive). ∴ here…♠ 16:29, 20 October 2005 (UTC)

It doesn't sound like an answerable question.... How big a number can you make up? Virtual terrain is just a scenery on a coordinate system, how big it is, is infinitely variable. Do you include areas from text-based games? Do you count randomly-generated dungeons? Do you count or the areas that can be gotten to, or just the populated areas? Do you count multiple instances of the same area? If you want my guess, I'd say you'd get maybe a third of a major continent from the foot-based MMOGs. If you count the flight/vehicle based MMOs, you could probably run over a few Earths. Tzarius 09:49, 21 October 2005 (UTC)

The nice part about games like CoH is that you can measure the size of the world -- it tells you. However, you also have to take into account the fact that in CoH the day is 60 minutes long, so there's a 24x time (and therefore, ostensibly, space) compression. I'm just going to give a guesstimate figure here, but given that Independence Port is about 2.5 miles long in game, at a 24x compression it'd be about 60 miles long in "real world" terms. Likewise, characters would be moving through it at 24 times their speed in game. That having been said, if you took length and width estimates, you could use that factor to calculate how many square feet exist in the CoH world. --FreelanceWizard 08:04, 23 October 2005 (UTC)

Gynecologist Paradox

I'm just perplexed, how can a male, heterosexual gynecologist still have a sex drive to have an intercourse with his wife after all day long looking at naked women? Thanks

Professionalism ☢ Ҡieff⌇↯ 17:33, 20 October 2005 (UTC)

You'll find that a lot of men do tend to bring their work home :-) but I have to admit that's one that I've often wondered about --Eye 18:53, 20 October 2005 (UTC)

• A gynecologist is not going to find every woman he works on attractive. Besides, if he gets aroused by naked women all day, why wouldn't he want to release the sexual tension and have some fun with his wife? Just looking isn't going to be enough and if he wants to keep his job he'd better not have sex with his patients. - Mgm|^(talk) 20:53, 20 October 2005 (UTC)

• A good doctor is trained to be have professional objectivity. Thus he does not think of the women as 'naked', they are patients only.

Which body parts are considered sexual arousing on sight is purely cultural. In our own society there was a time when the sight of a woman's ankles was considered sexual, so such people might well have asked us "how can you still be interested in your wife if you see strange women's ankles all day long ?". There are many societies where breasts are exposed, and a few where full nudity is practiced. In such societies, the sight of those things lose their sexual allure. Contact with those areas is another matter, however. StuRat 21:49, 21 October 2005 (UTC)

Yahoo dormant email accounts

Imagine I dont log in to Yahoo mail for many days. After how many days or months will my messages be deleted? Will my address also be deleted and recycled after a few days/months?

• Surely Yahoo! knows that answer best? - Mgm|^(talk) 20:54, 20 October 2005 (UTC)

I know that the account itself will never go away as Yahoo user accounts are permanent. -Drdisque 21:11, 20 October 2005 (UTC)

Not necessarily. Yahoo blocked my account after I didn't use ot for half a year. Unfair. Don Diego 23:01, 20 October 2005 (UTC)

But it's recreatable. User:Zoe|^(talk) 21:09, 23 October 2005 (UTC)

Consumption of electricity of speaker and fan

1) Does a speaker consume same amount of power >when the volume is low and >when the volume is maximum?

2) Does a Fan consume same amount of energy irrespective of whether it runs slow (minimum speed) or fast (maximum speed)?

No and No. However, the average power consumption of a speaker is quite low, so (barring a concert setup) you can safely assume "Yes" for the first one. Fans and other devices with motors pull more power, so it's easier to get a meaningful difference. Note that all of this, however, is relative: a desk fan's power consumption difference is probably meaningless if it's running off mains power yet significant if running off a battery. — Lomn | Talk / RfC 20:16, 20 October 2005 (UTC)

A speaker transforms electrical power into sound, so a speaker at a loud volume will be transforming more energy. Since power is the rate of change of energy, this is more power. The speaker transformation is lossy, so not 100% of the electrical power is transformed. Speakers are often rated in watts, which is the maximum power they can handle, often in RMS but some are rated at peak power. A fan turns against air and bearing friction, and similarly, draws more current as it turns faster. Dominick ^(ŤαĿĶ) 20:18, 20 October 2005 (UTC)

Buckminsterfullerene/Buckyball

What are the bond lenght and bond angle of buckyball? Some web-sites said it has single bond and double bond, while some web-sites said its bonding like benzene, is not single bond and double bond, is somehow between single and double bond. I can't find any information of the bond angle of buckyball, so please help me--

• If I remember correctly, buckyballs are made up of benzene rings in a soccer ball shape. Bonds in benzene are delocalized meaning that while you may draw the double bonds on one please there's also a structure where all double bonds are shifted one place. Since elektrons in such structures tend to move around, there's no way of knowing for certain where they are, so each of the bonds could be both single or double, which means they are something in between on average. - Mgm|^(talk) 21:02, 20 October 2005 (UTC)
  • No, buckminsterfullerene is not made up of benzene rings. It is made up of hexagons and pentagons of carbon, much like a soccerball. That means the bond angles are 120 and 108. I don't know and can't find the bond lengths right now. Also, the electrons are apparently NOT delocalized as Mgm says, and you never "know for certain where they [the electrons] are" whether they are delocalized or not. A simple google search will be more helpful to you than asking here. - Rangek 18:45, 22 October 2005 (UTC)

How about the bond angles of carbon between pentagon and two hexagons? And, is the bond lenght equal to 144pm(benzene bond lenght)?

In fact, I have searched in google, but there are not much information about details of buckyball structure. Does carbon inside buckyball have sp2 orbitals? But sp2 orbitals' all bond angles are 120 degrees. If not, which orbitals should it has?

Presumably the carbon atoms in buckyballs are indeed sp² hybridized. The bond angles may not be exactly 120°, but they're close enough; for an example of what really strained bonds look like, see cubane.

What you have to remember is that atomic orbitals are just approximations. In principle one could (as far as we know) determine the exact electron densities in a buckyball by solving the Schrödinger equation. This just happens to be somewhat difficult in general. —Ilmari Karonen 23:16, 24 October 2005 (UTC)

why is the Earth a sphere

why is the Earth a sphere - ????

For a given volume, a sphere has the least amount of surface area. Bubbles, water droplets, and stars also share the same shape for this reason. Dominick ^(ŤαĿĶ) 20:21, 20 October 2005 (UTC)

The Earth is spherical because it possesses sufficient mass to (approximately) collapse itself uniformly via its own gravity. Smaller astronomical bodies of similar density (like asteroids or Phobos and Deimos, the moons of Mars) do not have the necessary gravitational attraction and remain decidedly non-spherical.

Of course, it's worth noting that the Earth isn't precisely a sphere, even if you discount mountains, etc. The Earth's rotation imparts an equatorial bulge, and (if I recall correctly) the Southern Hemisphere is generally elevated with regards to the Northern Hemisphere. You can get into more detail on this at Figure of the Earth or from Isaac Asimov's book The Double Planet (an excellent read). — Lomn | Talk / RfC 20:29, 20 October 2005 (UTC)

The equatorial bulge is, if I recall, bigger than even the biggest mountains, in the sense that the north pole is something like 8 miles closer to the center of the earth than the equator is. -- SCZenz 21:40, 20 October 2005 (UTC)

To understand the above you have to realise that the Earth is largely non-solid. Only a relatively tiny crust at the surface is solid rock. DirkvdM 15:49, 24 October 2005 (UTC)

Sudden Change

Imagine I invented a machine that could morph something say like a rhino into a banana. I put the rhino in at one end and a banana comes out at the other end. (Yes it would be a big banana). Anyway imagine that I could watch the process and this process could be viewed in ratio terms. The change would first be 99 rhino and 1 banana then 98/2 and so on. As I watched the process I would have to decide whether or not the thing I was viewing was either a rhino or a banana as it clearly could not be both. It is either one or the other. When the rhino gets down to 51/49 it is still a rhino and not a banana. A point will arise where in order to complete the process of change the morphing rhino will have to leap the divide of the 50/50 point to become a banana. I say leap because it could not be possible to exist as two things at the same time It could not exist on the 50/50 point. To one side of the 50/50 it is a rhino, to the other side of 50/50 it is a banana. If infinity exists then the process would never cross the 50/50 point because the process would be infinitely dividing down towards the 50/50 point but never quite reach it… or as it came close to the 50/50 point the process would stall … until enough pressure for change had built up to cause it to leap the divide. Would the rhino suddenly change into a banana or gradually change? Is this a fair analogy of say, changing systems in nature, where evolution stays the same for donkeys years and then suddenly there is a big change. Or physics where an atom can absorb so much energy before suddenly jumping up to a higher energy level. Or say global warming, will our earths weather system under go a sudden change if enough pressure builds up? How close could we be to that change? Will I ever stop asking questions? :-) --Eye 20:24, 20 October 2005 (UTC).

IMHO, this is not a fair analogy, no conclusive proof has been offered for global warming, and the notion is unfortunatly unable to be determined given the political climate. In many places things have been getting hotter, and in some colder. Superimposed on this is the warming and cooling that occurs over centuries. At one time Greenland was pretty pleasent, and able to grow crops, now it is not. Dominick ^(ŤαĿĶ) 20:30, 20 October 2005 (UTC)

AFAIK, global temperature has been rising pretty steadily for a while. There isn't any debate over that, just over the idea that itis caused by human activities. -Superiority 01:40, 30 October 2005 (UTC)

Your analogy describes a Zeno paradox which, while an amusing word play, doesn't really enter into reality—despite all arguments to the contrary, Achilles really will outpace the tortoise. That said, some transitions in nature mirror this: electrons exist at distinct energy levels. However, macroevolution is more correctly viewed as continuous, as are trends in global climate. As for the final questions, they're philosophical. — Lomn | Talk / RfC 20:34, 20 October 2005 (UTC)

Just read some of the Zeno thingy. Isn't life fun.. :-)--Eye 20:45, 20 October 2005 (UTC)

An infinite series of times can actually add up to something non-infinite. Say you're doing the last percent, and you're "infinitely dividing it" – so 51%, 50.5%, 50.25%, 50.125%..... But, you need to remember you're also dividing up the time needed to perform the task. Also, pretend you have a super-camera that takes a picture every time you "divide it". If the process takes, for example, 100 seconds, you're taking "snapshots" at 49 seconds, 49.5, 49.75, 49.875..... You might be taking an infinite number of "snapshots" (and you can assemble them into an infinitly long movie), but your snapshots don't slow down time! Also, the first half of a percent takes half a second, then the next quarter takes a quarter of a second, then the next eighth takes an eighth....and it all adds up so that the last 1 percent takes 1 second. There's no paradox at all. AySz88^-^ 20:52, 20 October 2005 (UTC)

• In chemistry substances that change into others often have transition states which is a form in between the other two, which is actually neither rhino nor banana (if I were to keep to your analogy). Technically speaking, the rhino would stop being an actual rhino the moment it wasn't 100% rhino anymore. - Mgm|^(talk) 21:06, 20 October 2005 (UTC)

The rhino/banana thing was actually part of another thing I was thinking about to do with acid/alkaline. (Since you mentioned chemstry.) If the same analogy was used as the above rhino/banana scenario would a solution be classed as an acid until it became an alkaline? Is it possible to have a perfectly neutral solution?--Eye 22:29, 20 October 2005 (UTC)

Theoretically, yes. In the real world, small impurities are excluded, so a very, very weak acid could be classified as a neutral solution, until the basicity rises significantly. Regarding your rhino, maybe halfway through it would be a Very Confused Rhinoceros, Unless You Put the Head In First, In Which Case, It Would Be A Very Blissfully Ignorant Fruit. Incidentally, time flies when you're having fun, but fruit flies like bananas (and rhino-bananas, ergo). ;) Don Diego 22:58, 20 October 2005 (UTC)

I think you had better start by building a rhino-banana machine, and find out. Seriously though, you mentioned that the process was transitioning at one percent per measured interval, 100/0, 99/1, 98/2, etc. and it would have no reason to change as it approached 50/50. I have a machine that turns water into ice, and it doesn't slow down and stop for any so-called 'halfway'. The postulate you are hinting at is something that quantum physics is trying to deal with, in particular the Uncertainty principle. When is something what it is, and not something else? The basic answer is that as you measure it, it is what it is, and beyond your ability to measure it, it lies in an uncertain state, ready to jump to any possible state only when youre ready to come along to find out. It's been suggested that many thresholds apply to our universe, mostly from physicist Max Planck who suggested that there is a point beyond which it would require infinite energy to make an accurate measurement, and since that's not possible, for all you know everything exists in quanta of that particular level, and no more detail is possible. There is much reading available on the subject. --Jmeden2000 17:23, 21 October 2005 (UTC)

Regarding the comparison with evolution, I don't believe evolution ever moves "instantly" from one species to another, but do believe it moves quicker at times and slower at other times. We might choose to classify one individual as one species and it's offspring as another, but that is just due to the way we classify things, there wasn't necessarily a large jump between the two individuals. I would say periods of rapid evolution happen due to changes in environment (including the food supply and predators) and enabling changes in the species itself. In primates, for example, the opposable thumb originally evolved as a way to hold onto tree branches, but enabled tool use as well. This led to a rapid evolution of intelligence in primates to make use of this capability. StuRat 21:33, 21 October 2005 (UTC)

Not sure if this is helpful, but there are exampels of natural systems that suddenly switch mode. Transition of fluid flow from laminar flow to turbulent flow is one. As you increase the speed of water flow, the pattern doesn't change much. Then, over a very short range of speed it suddenly switches from one pattern to another. Above that the pattern stays relatively constant in the new pattern. The same could (could) easily apply to cilmate change. DJ Clayworth 20:40, 25 October 2005 (UTC)

solubility of hydroxylapatite vs. pH

I am trying to find out how the solubility of hydroxylapatite depends on pH. I have searched through a number of reference books, but I've been unable to find an answer. Ideally what I would like is a chart of pH vs. solubility for this mineral. Thanks if you can help! ike9898 20:51, 20 October 2005 (UTC)

If you have access to scientific journals, through a library or university, you could have a look at some of the articles that appear on this Google scholar search. -- Rune Welsh | ταλκ | Esperanza 14:19, 23 October 2005 (UTC)

Red/turquoise contrast problem.

I have noticed that if a strong red and a turquoise or blue-gray border on one another, I find it very difficult to look at. It's not a kind of colour-blindness, because I can clearly see the difference between the two; actually, it's more like the contrast is too great to see properly. The border appears to sort of crawl and it is unpleasant to focus on. If I see these two colours bordering one another even in my periphery it is distracting, almost as if something is blinking or moving in my periphery. Does anyone know what this is? Is it common? Bryanmtmorrison 21:01, 20 October 2005 (UTC)

I have experienced that also, and discussed it with others, so I can tell you that other people see the same thing. ike9898 22:07, 20 October 2005 (UTC)

While the area we focus on sees the most detail, the periphery is good at detecting movement. In your case it sounds like the "threshold" for seeing movement is too low, and you eyes/brain detects movement that isn't really there. StuRat 21:19, 21 October 2005 (UTC)

Carbon

what are 4 uses of carbon?

You can use it to do your own homework--see the rules at the top of this page. But I bet reading our carbon article would be a real good place to start. -- SCZenz 21:38, 20 October 2005 (UTC)

I'll bite:

1. Nuclear reactors
2. Dentistry
3. Space elevators
4. Life

—Ilmari Karonen 23:00, 24 October 2005 (UTC)

Oh you are cruel. DJ Clayworth 20:34, 25 October 2005 (UTC)

Plants Of The Amazon Jungle

While watching a programme on T.V. I came across an unfamiliar word- Aseyi Berry- it si supposed to be the berry of palm trees. I am not certain of the spelling.

You'll be wanting our Açaí Palm article. :) --Ashenai (talk) (Galatea!) 22:42, 20 October 2005 (UTC)

white film on magnesium strip, plz help ASAP

Ok, before doing an experiment, why should you polish and remove white film off a magnesium strip?

That white film is a layer of magnesium oxide, which forms when magnesium is exposed to air. Presumably, you want to do an experiment on magnesium, not magnesium oxide, so you first must clean the film off to get down to the magnesium underneath. — Laura Scudder | Talk 23:22, 20 October 2005 (UTC)

well, do you want to experiment on pure magnesium, or do you want your results tainted by the presence of oxidation and impurities? Lethe | Talk 23:23, 20 October 2005 (UTC)

On pure magnesium, THANK YOU VERY MUCH

How to find experimental percent composition of magnesium and oxygen in Magnesium oxide?

How do you do such thing?

Please do your own homework. Hint: Mass increase. -- Ec5618 23:39, 20 October 2005 (UTC)

These are a little bit complicated, can some one help? To be more exact, I started with 0.16 g of Mg after heating it, I ended up with 0.24g of MgO. I want to find the experimental percent composition of magnesium and oxygen in Magnesium oxide.

Bigger hint: have a look at the articles on magnesium and oxygen and find out the atomic mass of each. From that you should be able to figure it out.

No, that will give you the theoretical percent composition. Oxygen is rarely analysed in elemental analysis, magnesium is usually analysed by atomic absorption spectroscopy. Or maybe your teacher just wanted you to say that your 0.16 g of magnesium are still present in your 0.24 g of magnesium oxide... See also Antoine Lavoisier. Physchim62 03:53, 21 October 2005 (UTC)

Actually, not just the theoretical mass distribution. When you burn the magnesium, it will gain weight. A negligible amount of magnesium will be lost. Where did that 0.08 grammes of weight come from? 0.005moles of .. Ok, I'm done hinting now. -- Ec5618 11:35, 21 October 2005 (UTC)

• Surely we've got a magnesium oxide article? - Mgm|^(talk) 08:16, 22 October 2005 (UTC)

Are you sure you burned all of your magnesium. It may be better to use a thinner wire or shavings so it burns completely. - Mgm|^(talk) 08:18, 22 October 2005 (UTC)

October 21

Coulombs law

How does one calculate a question like this:

Two charges with specified values for charge, which are held a distance apart, an extra charge is introduced and is moved along the line they are on. Where would the new charge experience a zero resultant force?

---MJH

Set up a coordinate systemm that seems easy to you, like putting one of the stationary charges at x=0. Add up the forces from each of the two charges (from Coulomb's law) on the extra charge, making sure the signs are right for the directions they point. Then solve algebraically for when the sum of forces is zero. -- SCZenz 00:08, 21 October 2005 (UTC)

Can you elaborate a little more? What do you mean by sum?

Normally it would be a vector sum, but in this case the problem is one dimensional. I mean write down the force from coulomb's law from each charge separately, using your chosen coordinate system for both (your r's will have to be changed), and then literally add up the numbers. (Make sure the signs are right to reflect the direction of the forces!) -- SCZenz 00:35, 21 October 2005 (UTC)

Internet Protocol

Question: what is a Level 2 Internet Security Protocol

Answer: do your own homework. Hint: Find out what level 2 means by starting at OSI model. --Robert Merkel 13:27, 21 October 2005 (UTC)

Also compare SSL and IPSec. --R.Koot 15:46, 21 October 2005 (UTC)

(Neither of which is a level 2 protocol.) Gdr 10:55, 22 October 2005 (UTC)

rosenberg generator

hi wikipedia. myself rutuparna andhare. i want to know information about the rosenberg generator. this is a special purpose m/c. i want its construction, working and digram. my e mail id is (removed)

Hi Rutuparna. You might need to try some books on electrical engineering for this kind of detail; all we have at Wikipedia is the article on motor controller. Maybe some electrical engineering or mechatronics people will be able to give you some more specific help. Sorry I can't be of more assistance. --Robert Merkel 11:53, 22 October 2005 (UTC)

I am an EE, and I used to teach. I have not used or been in contact with a "Rosenberg generator" if you have any basic details, I would love to fill in the article. I think it is a DC Motor/generator, thats only by looking at litarature that didn't say much except what I told you. Amusingly enough, google returned some link to the free power and perpetual motion crowd. I found no vendors for such an item, but I have not looked at the stack at my workplace. If you want someone to build you one, or tell you how to build one, this is beyond the scope of wikipedia. Dominick ^(ŤαĿĶ) 14:07, 22 October 2005 (UTC)

Light in a box

Why can't you trap light in a mirrored (on the inside) box? When I first asked my dad this, he told me that if you cut off the source of the light when shutting the lid, the wave can't exist inside the box. This doesn't satisfy me, however, because light can still travel through space, and, indeed, be bounced off mirrors, after a star has died.

Say light is coming from a distant star. I bounce it off one mirror and set up another mirror far away parallel to it. Would it keep bouncing between them? The energy decreases rapidly with distance because it all disperses, sure, but the same would not be the case in an enclosed-on-all-sides box.

I'm guessing that it's because the mirrors absorb energy with each bounce and that, in the tenth of a second it takes me to close the box and open it again, the light has bounced around a zillion times and lost all its energy. Is that right? And would it be theoretically possible to have a perfect mirror in which this energy loss (if that's what it is) didn't occur?

• Sure it's possible. In fact, there are perfectly legitimate standing waves of light in classical electromagnetism. And yes, what really happens if you bounce light a lot is the energy gets turned into heat on the walls of the box. -- SCZenz 04:43, 21 October 2005 (UTC)
• If you can rig up a strong enough magnetism or gravity source, you can trap light without having it lose energy, just by keeping it in a stable orbit. (which might be a bit tricky with magnetism). Tzarius 09:34, 21 October 2005 (UTC)

light is neutral, and so will not be affected by electromagnetism (neglecting quantum effects). Gravity would work, however. but the radius of a lightlike orbit is on the order of the Schwarzschild radius, so if you want to trap light with gravity, you'd better have a black hole handy. -Lethe | Talk 09:46, 21 October 2005 (UTC)

• But there is light inside a box, just light that you can't see. When the light bounces off the walls, it doesn't lose all its energy, it shares that energy with the walls of the box. When everything has calmed down (very, very quickly), the light and the walls have the same "energy" (strictly, the same temperature), and you can't tell them apart. See also black body radiation. Physchim62 12:50, 21 October 2005 (UTC)

• The very best mirrors that you can make use special optical coatings and reflect about 99.999% of the incident light (in a narrow wavelength range). They are used for cavity ringdown spectroscopy. If you place a pair of them 0.5 m apart, light bouncing between them drops to about 0.1% of its starting intensity after 345000 round-trip bounces, or about 1.1 milliseconds after the light starts. So even with extremely good mirrors, and ignoring all other factors, the light doesn't stay around for very long. --Bob Mellish 15:45, 21 October 2005 (UTC)

I Like this kind of question. Think of another.--Eye 16:49, 22 October 2005 (UTC)

how to prepare soft drinks?

Prepare them for what? Could you please clarify your question a bit more? -- Daverocks 12:03, 21 October 2005 (UTC)

See, for example, OpenCola. TenOfAllTrades(talk) 13:04, 21 October 2005 (UTC)

Some simply open the container and drink it. You open the cap and pour it over ice. A slice of lime as a garnish is sometimes used. Optionally, rum can be added to Cola, to make a Cuba Libre. In rural areas of the United States cola without rum it is a common breakfast beverage. Soft drinks without coloring, preferably lemon lime flavors, can be used to clean automotive battery terminals. Dominick ^(ŤαĿĶ) 14:14, 21 October 2005 (UTC)

It's only a Cuba Libre if there's a lime. Without the lime, it's a Rum and Coke.  :) User:Zoe|^(talk) 21:05, 23 October 2005 (UTC)

If you are asking how they are prepared in restaurants, most use a machine which blends soda water (seltzer) and syrup. Bottled soda (premixed) is sometimes also available. StuRat 21:01, 21 October 2005 (UTC)

lightning?

can the energy (electricity) in lightning be saved or stored? why, how or why not?

mckeancharles@(email removed)

I suppose if you had a really big capacitor hooked up to a lightning rod, you could store the electricity, but all in all, you would save about 500 Megajoules, or 139 kilowatt hours, which would save you between £8 and £15 pounds ($15 - $25) (at 6p per kWh). Not all that worth it. smurrayinchester^{(User), (Talk)} 14:15, 21 October 2005 (UTC)

BTW, don't post your email address here. Spammers read this page too. smurrayinchester^{(User), (Talk)} 14:17, 21 October 2005 (UTC)

The problem is that lightning is so irregular that collecting it would require millions of lightning rods all over the collection area. The strength of each bolt is quite different, too, so you would need to be able to handle the maximum case to prevent your equipment from getting fried. Then you would need an efficient way to store the energy until needed. The cost of all this far exceeds the benefit, at least at the currrent cost of electricity. Perhaps some future technology, like balloons carrying thin metal fibers, can make it profitable. StuRat 21:09, 21 October 2005 (UTC)

Mind you, actually, if lightning strikes the Earth 100 times a second as some people say, covering the entire planet in lightning conductors could save about £800 per second, or £69,120,000 per day. Of course, the cost of installing the billions of rods needed would probably take years to recoup. smurrayinchester^{(User), (Talk)} 09:32, 22 October 2005 (UTC)

One billion rods with collection mechanisms and connectivity to the power grid would be rather expensive, especially those built in Antarctica, over oceans, etc.

Let's say they could each be built for £1,000,000. That would put the total cost for 1,000,000,000 rods at £1,000,000,000,000,000. At £69,120,000 per day that would take 14,467,592 days to pay off, which is close to 40 thousand years. I doubt if they would last that long.

A more practical approach would be to only place rods in areas of frequent lightning strikes, like the top of hills in areas of frequent thunderstorm activity. I still doubt if such a system could be made profitable, however. StuRat 14:29, 22 October 2005 (UTC)

I suspect it's still a losing game. The CN Tower in Canada (according to our article) is struck by lightning about 75 times per year. The Empire State Building (according to various offsite pages) gets about a hundred strikes per year. If we optimistically assume that the best locations are three times that good, then we get three hundred strikes per year times twenty dollars per strike: $6000 per year. (That assumes that the storage and redistribution of the electrical energy is 100% efficient.) I can tell you that storing a 500 megajoule lightning strike is going to cost a lot more than that.... TenOfAllTrades(talk) 14:54, 22 October 2005 (UTC)

I'm not convinced by any of this millions of rods stuff. Lightning takes the route to Earth that has the least electrical resistance. By definition that's where it needs to go. If there's a whopping great capactitor in the way it'll avoid it. Shantavira 16:04, 22 October 2005 (UTC)

If lightning hits a lightning conductor, then it hasn't worked. It is designed to dissipate electrical charge before it builds up enough to actually create a lightning bolt Aimaz 12:53, 22 November 2006 (UTC)

Crocodilians in Guatemala

I've been watching this season's edition of the reality show Survivor, which takes place in Guatemala. The contestants are living in two camps along the banks of some unnamed river. This river is infested with lots of crocodilians. Now, the contestants and the host keep calling these things "crocs". "Oh, so-and-so was almost eaten by a croc!" "The winning team will receive a swim cage, 100% croc-proof." But I could've sworn that Central America had alligators and not crocodiles. Searching around on the web, I've found the same confusion on various websites.

So which is it? Does Guatemala have alligators or crocodiles? What's menacing these people? And are they really known man-eaters? --BrianSmithson 14:06, 21 October 2005 (UTC)

Both caiman and crocodiles [53] [54] are in Guatemala. Krieky! Alligators (new world 'gators) are in the lower United States. [55] I used the University of Florida site, also known as the Gators. Such reptiles till attack a lot of things moving in murky waters, but do not prefer human flesh to other types of food. Dominick ^(ŤαĿĶ) 14:20, 21 October 2005 (UTC)

P.S. The Caiman is classed as an alligator, but is not the common 'gator that you may be familiar. Dominick ^(ŤαĿĶ) 14:22, 21 October 2005 (UTC)

Muchos gracias! For the first few episodes, I kept screaming, "Those aren't crocs, you idiot! Those are alligators!" Guess I should be voted out of the tribe. I suppose the animals they keep showing could be caimans, though. BrianSmithson 20:58, 21 October 2005 (UTC)

I may be totally talking out of my hat, but I believe you can tell caimans from crocs by their teeth -- when the mouth is closed, you can't see a croc's teeth, but you can see the caiman's. User:Zoe|^(talk) 21:03, 23 October 2005 (UTC)

All about health

Q1. For how long has a brush been in use that will reduce its plaque removing ability up to 30% than a new one?

Q2. How many hours does a baby spend in a baby walker that will delay its first step by up to 4 days?

Q3. Less than how many hours of sleep a night will run a person 2 to 3 times the risk of heart attacks?

Q4. What waist measurement or over is thought to increase a person's risk of getting a heart attack?

Q5. How long did people need to train with weights per week in order to lower their risk of coronary heart disease by 23%?

Q6. After what age would people start losing muscle mass and strenght caused by hormonal changes?

Q7. What % of man who took annual holidays would be less likely to die of a heart disease than those who'd skipped time off?

Q8. How many mililiters of cooked soya beans would contain the protein equivalent of a 110 gram hamburger or 500 mililiters of milk?

Please let me the answers. My email address is <removed> Thanks and regards Raj Ramoo

Almost all of these questions suffer from a problem of overspecificity. They ask a question that due to natural variability in the subject, there cannot be a specific answer to the question. For example, in #1 variation in material used would likely have a great impact on the length of use before it's usefullness declined. Also many of these may or may not have ever been specifically researched, or if they have, to use the first one as an example, the toothbrush companies keep the information secret to try to gain a competitive advantage. In other cases, such as #7, there may be a certain study that found a number, but that doesn't mean that number is accepted fact, and wouldn't be contradicted by another study. Again, the variation is just too great. - Taxman ^Talk 15:29, 21 October 2005 (UTC)

Q8. How many mililiters of cooked soya beans would contain the protein equivalent of a 110 gram hamburger or 500 mililiters of milk?

Protein contents according to the USDA food nutrition database (in 100 g edible portions):

• Soybeans, mature cooked, boiled, without salt: 16.64 g

If your hamburger means meat + bread, then 110 of hamburger roughly equals to 88 g of cooked soybean. However, the volume of the soybean depends on the way you pack it. You can squeeze the cooked beans into a cup or just put the dry/cooked beans into a measuring cup.

• McDonald's Hamburger: 12.36 g
• Burger King Hamburger: 14.18 g
• Wendy's Classic Single Hamburger, no cheese: 12.63 g
• Fast foods, hamburger, regular, single patty, plain: 13.69 g

If you hamburger means beef patties, then 110 of ground beef roughly equals to 167 g of cooked soybean.

• Beef, ground, 75% lean meat/25% fat, patty, cooked, pan-broiled: 23.45 g
• Beef, ground, 85% lean meat/15% fat, patty, cooked, pan-broiled: 24.62 g
• Beef, ground, 95% lean meat/5% fat, patty, cooked, pan-broiled: 25.80 g

Currently I am out of milk so I don't know how heavy is 500 ml of milk (936 ml = about 1000 g, I guess). I'll assume 500 ml of milk weighs 534 g.

534 g of milk roughly equals to 107 g of cooked soybean.

• Milk, whole, 3.25% milkfat: 3.22 g
• Milk, reduced fat, fluid, 2% milkfat, with added vitamin A: 3.30 g
• Milk, lowfat, fluid, 1% milkfat, with added vitamin A: 3.37 g
• Milk, nonfat, fluid, with added vitamin A (fat free or skim): 3.37 g

Soy protein is fairly "complete". It is comparable to milk or meat proteins. -- Toytoy 15:27, 25 October 2005 (UTC)

Q6 "After what age would people start losing muscle mass and strenght caused by hormonal changes?" At the average of 32, your putitary gland stops producing hormones. Within 3~5 days, ( the halflife of growth hormones is about 1.5 days ) you start loosing musle mass. The varibility of the average age is 1.6 years, ( at least it was when the study I read in 1988 was published. ). It is rapid until the age of 44, then levels off. Much research is still going on regarding this question, and the mechanism for it. It relates to the extension of life expectancy. Ill look for recent studies. Artoftransformation 12:55, 30 October 2005 (UTC)

Q5. How long did people need to train with weights per week in order to lower their risk of coronary heart disease by 23%? I believe its less than 13 minutes. Once again. Old data. Artoftransformation 12:55, 30 October 2005 (UTC)

Water

If 84% of sea water is evaporated every day, why isn't water salty? Please have the answer in soon. Contact my email: (removed)

If you read the top of this page, you'll find that we don't reply by email. But to answer your question, it's because the water evaporates and leaves the salt behind. (I'm not sure what your 84% statistic means though. -- SCZenz 15:05, 21 October 2005 (UTC)

I'm positive that statistic is false. --Quasipalm 18:05, 21 October 2005 (UTC)

Well, "why isn't water salty" doesn't exactly make sense. Sea water is, indeed, salty. --Borbrav 20:57, 21 October 2005 (UTC)

I think he/she means why isn't all water salty. - Akamad 23:51, 21 October 2005 (UTC)

In that case, river and lake water is continually replaced by fresh water, in the form of rain, and the salt is washed out to the ocean. An exception is a terminal lake, which does not lead to the ocean, then salt does accumulate. Such lakes, like the Dead Sea in Isreal/Palestine and Salt Lake, Utah, USA get extremeley salty, even more salty than the oceans. The only limit is when the salt reaches it's solubility level in water and deposits on the shores and bottom of the lake. StuRat 14:10, 22 October 2005 (UTC)

Some bodies of water do not get salty, if there is no salt in the surronding geology to leach into the water. Fossilized water, water stored underground that is not flowing, sometimes is not salty. Florida has a few depositsof water that do not flow, and do not get salty. I think the OP was wondering if "84%" of the water evaporated why are the oceans not supersaturated. The answer is that 84% of the water does not evaporate. Dominick ^(ŤαĿĶ) 14:16, 22 October 2005 (UTC)

The atmosphere has water in it, some of which falls to earth (rain, snow, etc), and every day some of the water on the Earth evaporates back into the atmoshere. Around 84% of the water that evaporates back into the sky evaporates from the oceans, but is replaced by the water that returns to the oceans (rain, snow, rivers, etc.) so the water content does not change day to day (but does change century to century). The stuff dissolved in the oceans varies measureably place to place and century to century. WAS 4.250 01:39, 26 October 2005 (UTC)

INDIA

Development of India in the field of science and tecnology.

Without a complete question it's hard to determine what it is that you're looking for. Perhaps you should read the article on India and its associated articles and then maybe come back with a more solid question. Dismas|^(talk) 17:12, 21 October 2005 (UTC)

• India has developed. To the extent that it knows to put an "h" in technology, and much more. It will continue to develop. If you want a better answer, do your own homework!. Physchim62 17:13, 21 October 2005 (UTC)

• You could look at articles in Category:Science and technology in India. Indian science might be a good starting point. -- SCZenz 17:14, 21 October 2005 (UTC)
• And please realise the search box is on the left of the page. -- Rune Welsh | ταλκ | Esperanza 14:05, 23 October 2005 (UTC)

concerning the ontological status of dimensions.

Hello, My question is, what is the ontological status of a dimension? Is its status objective, i.e., a characteristic of reality or of a thing in reality (these are different answers) or subjective, i.e., a way in which we perceive reality? Thank you, Arnon Shahar. --217.132.229.134 17:55, 21 October 2005 (UTC)

As a scientist, I have to say I'm not sure how we would tell. Assuming they're a property of reality is very helpful in making physical models. Also, there are physics models with an extra dimension, or even 7, but they include evidence of why we don't see such things normally. -- SCZenz 19:34, 21 October 2005 (UTC)

The word "dimension" can be used to refer to psychological realities (perceptions), mathematical structures, or aspects of scientific theory backed by empirical evidence. As a math structure space can be infintely divisible. As used in an empirical scientific theory, there is always a smallest as yet verified divisibility. As used to refer to psychological realities, new agers and others find no limit to their ability to misuse scientific sounding words. WAS 4.250 01:52, 26 October 2005 (UTC)

Partial vs total differentiation

The Stackelberg competition article gives the condition for a Nash equilibrium as ${\frac {\partial \Pi _{1}}{\partial q_{1}}}=0$. I don't see why this uses a partial derivative, rather than a total derivative and asked the question (with more details) on Talk:Stackelberg competition#term missing a while ago. Can anyone confirm or refute my suspicion that this is an error, please? Common Man 18:25, 21 October 2005 (UTC)

mathematically, it seems to depend on whether q1 and q2 are independent or not. I don't know anything about economics, so I'm not sure. The phrase "given the output of the leader (firm 1), the output that maximises the follower's profit is found" seems to suggest that q1 should be regarded as fixed (given) and the value of of q2 which maximizes with respect to that fixed q1 is sought. In that case, the partial derivative is correct. -Lethe | Talk 19:07, 21 October 2005 (UTC)

You're right – your argument holds for the value of q2. So the first pair of equations (involving Pi_2) need to consider the partial differentiation. Now that you pointed this out, I see why someone would use partial differentiation for Pi_1, for the sake of symmetry. It's clearly more elegant. But is it right? (Drilling further down, I realize that this distinction is somewhat arbitrary anyway. Arguably, the Pi_2 equation seems like a mongrel between a partial derivative (with q1 constant) and a total one, since P and C_2 are explicitly differentiated. This is getting ugly!) Common Man 20:09, 21 October 2005 (UTC)

Incidentally, could someone take a stab at clarifying the beginning of the article? Speaking as a layperson, I'm having real trouble figuring out what the heck Stackelberg competition actually is. TenOfAllTrades(talk) 20:39, 21 October 2005 (UTC)

As a start, noted that the context of the article is in game theory. Ancheta Wis 22:09, 21 October 2005 (UTC)

Thanks for the answers, but this is actually, as the headline says, a question about partial vs total differentiation. I'm neither an economist or game theoretician either. But trust me, you don't have to be one to answer the original question. It is pure mathematics. As a first step, maybe I should ask the following context-neutral question:

Given

f = f(x,y,z)

y = y(x)

z = z(x)

We know that

df/dx (where y=constant and z=constant) is called partial derivative

df/dx (where y=y(x) and z = z(x)) is called total derivative

What do you call

df/dx (where y=y(x) and z = constant)

and what's the mathematical notation for it? Common Man 22:36, 21 October 2005 (UTC)

It is a partial derivative as well. For a boundry condition? My experience in calculus is for electromagnetics, not game theory. Same notation: ${\frac {\partial f}{\partial x}}$ Dominick ^(ŤαĿĶ) 23:37, 21 October 2005 (UTC)

You can borrow some notation from thermodynamics, (but is also used elsewhere). Suppose f = f(x,y,z). Then

$\left({\frac {\partial f}{\partial x}}\right)_{y,z}$

is the partial derivative of f taken with respect to x keeping y and z constant.

But in the context of this question, it seems that you want to define

$\left({\frac {df}{dx}}\right)_{z}$

and this generally does not really make much sense. You need some sort of transformation to rigorously define what you would like to do here. --HappyCamper 15:50, 22 October 2005 (UTC)

I have seen ${\frac {\partial f}{\partial x}}{\Bigg |}_{z}$ but you are right, it is vague. I made it clear in text, but rarely it was an issue except at a boundry. Dominick ^(ŤαĿĶ) 14:43, 23 October 2005 (UTC)

Really? I didn't know that notation was in use too. That explains a few things now in another paper I was reading. I kept on thinking that it meant ${\frac {\partial f}{\partial x}}{\Bigg |}_{x=z}$, in other words, differentiate with respect to x, and then evaluate the result for x =z, which seemed to be highly redundant. --HappyCamper 14:55, 23 October 2005 (UTC)

Calculus is hard to express without good shared notation. Partial derivatives are done where more than one variable may change. They differ in from the "full" derivative only when a value is fixed. I would prefer to write ${\frac {\partial f}{\partial x}}{\Bigg |}_{z=0}$ or ${\frac {\partial f}{\partial x}}{\Bigg |}_{z=1.23e4}$ assuming f(x,y,z) still contains the y variable. The partial derivative will only get really different than a full derivative when I increase the order, for some reason writing, ${\frac {\partial ^{2}f}{\partial x\,\partial y}}$ but thats a different headache. Dominick ^(ŤαĿĶ) 17:55, 23 October 2005 (UTC)

Thank you, guys, that settles the terminology and notation. (I will use Dominick's form for the fist equation with Pi_2 after explaining it somewhere). So what do you think about the second equation (with Pi_1)? To keep economy and game theory out of it – what they do is simply: Find the maximum by setting the derivative to 0 (and hoping that it isn't a minumum or saddle point). For this, they should use the total differential, so the current formula lacks a term, correct? (Maybe that discussion should be kept at Talk:Stackelberg competition#term missing.) Common Man 01:43, 24 October 2005 (UTC)

October 22

What are the bond angles of buckyball?

They are 120 and 108 degrees, aren't they?

Someone asked that earlier today. — File:Ontario trillium sig.pngmendel ☎ 20:41, 21 October 2005 (UTC)

No one answered it though, so are they 120 and 108 degree?

No, they must be less than 120°, otherwise you would have flat sheets as in graphite. Physchim62 12:18, 22 October 2005 (UTC)

Buckyballs (C₆₀) are made of pentagons and hexagons, exactly like a soccer ball. Presumably the bond angles in the hexagons are 120° and in the pentagons 108°. With each carbon being part of two hexagons and one pentagon, the sum of bond angles for each carbon is 348°, which is less than the 360° required for a flat sheet. —Ilmari Karonen 22:31, 24 October 2005 (UTC)

Peak busy hour

Generally, what is the percentage of total daily calls that occur during peak busy hour in a voice network?

• What country are we talking about? - Mgm|^(talk) 08:26, 22 October 2005 (UTC)

PRODUCTION FUNTION CURVE (**** URGENT****)

WHY WE ARE PRODUCING PRODUCT AT THE POINT WHERE THE CURVE STARTS DECLINING?

PLEASE SEND ME THE ANSWER WITHIN 6 HRS OF MY QUERY, AS IT IS VERY IMPORTANT TOPIC FOR ME.......

Respectfully, ___ Muthukannan S. B.E, MBA MADURAI (INDIA)

If I understand the question, it falls into the general category of "why should a company produce additional units at a lower than optimal profit margin". There could be many reasons for this:

• They want to maximize the amount of profit, not just the rate. While a 10% rate of return on a million dollars is better than a 9% return on a million, a 9% return on a two million may well be better than either, depending on your perspective. A single owner of a company would rather have the 180,000 profit that would generate than the 100,000 profit in the previous case.

• The larger production may allow a greater market share, which will then lead to greater future profit amounts and rates.

• They may have significant fixed costs which are better divided among many units than a few.

StuRat 20:46, 21 October 2005 (UTC)

Can you be a bit more specific who "we" is, and which product and which curve you refer to? WRT "Respectfully": Using all caps is regarded as shouting, which is not considered respectful. Nor is setting deadlines without explanation. Common Man 20:32, 21 October 2005 (UTC)

Is his homework due in six hours? TenOfAllTrades(talk) 20:37, 21 October 2005 (UTC)

It is because that is the point where marginal cost begins to exceed marginal benefit. - SimonP 20:41, 21 October 2005 (UTC)

space shuttle

what factors did the engineers consider when designing the tiles for the space shuttle?

This seems like a homework question, but I'll give you the benefit of the doubt. Ceramic tiles are able to withstand intense heat. They need not resist great (bending) forces, but they need to be able to cope with vibrations. Because of this, the tiles are connected to the main body of the shuttle via a dampening support frame. The tiles probably have variable thickness, too.

As the article states, that the original silica-based ceramic tiles need to be removed for inspection for damage after every flight, and they also soak up water and thus need to be protected from the rain. The latter problem was initially fixed by spraying the tiles with Scotchgard, but a custom solution was adopted. Later, many of the tiles on the cooler portions of the Shuttle were replaced by large blankets of insulating feltlike material, which means huge areas (notably the cargo bay area) no longer have to be inspected as often.

See Thermal Protection System. -- Ec5618 23:45, 21 October 2005 (UTC)

Apart from the reasons in the excellent response above, weight is a critical issue. Although they are ceramic, when I saw a TV scientist mucking around with an old Space Shuttle tile it seemed to have a density resembling foam rather than the tiles we have in our homes.--Commander Keane 00:16, 22 October 2005 (UTC)

Of course, they must not only withstand heat, but also act as effective insulators to prevent that heat from reaching the shuttle body. StuRat 02:26, 22 October 2005 (UTC)

AIDS

Is it that a person infected with AIDS will sure die ??

we can be sure that everyone dies in the end, with or without AIDS -01:47, 22 October 2005 (UTC)

Assuming you meant to say "...die from AIDS", then no, for several reasons:

• Medications exist which seem to be able to prevent, indefinitely, death from AIDS. The "AIDS cocktail" seems to be effective, although very expensive. In some patients, they seem to develop a drug resistant strain of AIDS. This can be managed by changing the mix of medications, however, at least in the short term.

• "Infected with AIDS" is rather vague. Some people are HIV positive, meaning they have been infected by the virus, but never show any symtoms of AIDS. These people appear to have a natural immunity. Interestingly, the same immunity from the bubonic plague also appears to offer immunity from AIDS.

• Genetic engineering may offer a way to extend this immunity to all people within a few years. So, if someone with AIDS can survive until then, they may be cured.

StuRat 02:14, 22 October 2005 (UTC)

• People don't get infected with AIDS, but with the HIV virus. When this happens they are HIV positive, but it may take many years before they even show the slightest sign of having AIDS. Some people never develop the symptoms and die of other causes. So while people do die in the end, AIDS may not neccesarily be the cause of their death. StuRat was right. There's drugs that slow down the disease allowing the infectee to have a fairly normal life without having to worry about dying, provided they do regular checkups with their doctor. - Mgm|^(talk) 08:31, 22 October 2005 (UTC)

• Every human will surely die, regardless of whether they have AIDS or not. -Drdisque 16:28, 22 October 2005 (UTC)

• Ask Magic Johnson. It seems HIV+ people with enough money can battle AIDS for a very long time. --Quasipalm 17:17, 22 October 2005 (UTC)

• Also note that people with aids usually die because of so-called "opportunistic diseases". These diseases wouldn't normally kill a healthy person with proper access to healthcare, but are a serious danger to people who have developed AIDS. -- Rune Welsh | ταλκ | Esperanza 13:52, 23 October 2005 (UTC)

• • You all forgot one reason: They might get run over by a bus or something. A tonne of steel moving at 80 kph doesn't discriminate between HIV-negative and -positive people. — JIP | Talk 16:27, 24 October 2005 (UTC)

Equation editor on Word

Is there a shortcut to get the equation editor on Word 2003? Or do you have to go to Insert>Object>Microsoft Equation Editor everytime? A way to get it on the toolbar would be handy. Thanks Akamad 07:04, 22 October 2005 (UTC)

• No idea about Word 2003, but under older versions you could go to the Tools/Customize... menu, choose the "Commands" tab, then category "Insert", and scroll down to find an "Equation editor" button which you could drag to any toolbar. I suspect it should work the same way in new versions of Word. --Bob Mellish 07:19, 22 October 2005 (UTC)

Thanks kind sir :-) That works nicely. As it turns out you can also assign keyboard shortcuts from the same place, which is exactly what I wanted. Akamad 07:45, 22 October 2005 (UTC)

Hmmm...I added it both to my toolbar and assigned it a keyboard shortcut, but they are not there when I restart Word. Any ideas? Thanks :-) Akamad 09:05, 22 October 2005 (UTC)

Make sure that Word is saving the toolbar changes to Normal.dot, not just the current document. I know under Word XP there's a clear drop-down box which has the options of saving either to Normal.dot or just the current document. If you're getting to it the same way in Word 2003 (through the Tools/Customize menu), it should have it there as well.

That should work, but if you're sure it's saving to Normal.dot ("sure" as in you can clearly see the option is Normal.dot), then you can create a macro in Word which will automatically do anything. It's under Tools -> Macro -> Record New Macro. You can assign the shortcut to the macro to toolbars or keyboard, but either way, make sure it's saving the macro to Normal.dot. When you finish saving the macro settings, it will start recording the macro. Then get open the equation editor the way you usually do it, and stop recording the macro. Then you can use this macro later to instantly do what you just did. -- Daverocks 10:30, 22 October 2005 (UTC)

I think there is something wrong with my Normal.dot file, because anything I save to it seems to be gone when I re-open Word, I might try re-installing Office. Thanks for your help :-) Akamad 00:34, 23 October 2005 (UTC)

Toothpaste Vs Charcoal

I need to write an essay on Toothpaste, its history, the devolopment procedures of toothpaste (including any equations or formuals and why it was made) and any benifits to this compound. I also have to write the same information about charcoal and how it can be used as toothpaste and i need to write the positives and negatives side of using toothpaste instead of charcoal. As you can tell, I'm having no difficulties finding information about the toothpaste side, but i am finding it extremley hard to find some information abut the charcoal side. Any information about charcoal and toothpaste would be of great use to me.

Thank you

A google search for charcoal toothpaste [56] reveals pages like this: [57]. I'm not recommending that page in particular, but you could look around like that. Our article on toothpaste may help also. -- SCZenz 09:29, 22 October 2005 (UTC)

Thank you for your reply, but i am still in need for more information about charcoal. I have already looked up the sites that you advise me too see and managed to find some information about toothpaste but not charcoal. Again thankyou for your help and any information about charcoal would be of great use to me.

You might try asking on camping forums. When I was a Boy Scout I was told that in a pinch, chewing coals from a fire (which had cooled first of course) cleans teeth. Since I was told this on a camping expedition by someone who was instructing us on various ways to use nature I would think that someone on a camping forum may know more about using coals in this fashion. Dismas|^(talk) 15:57, 23 October 2005 (UTC)

Do wild animals snore?

I guess they don't. An animal that snores would always attract predators or alert preys. Such a genetical feature shall be eliminated by natural selection in no time.

I also don't think ancient humans and earlier hominids snored much. I guess snoring marks the rise of our undefeatable human civilization where men in bed are no longer eaten by big cats. As a result, bad genes are not eliminated and people start to snore. -- Toytoy 10:08, 22 October 2005 (UTC)

From the New York Times

Q. Do any animals besides people snore?

A. Yes, some animals do snore, according to anecdotal reports and personal observations, said Penny Calk, manager of the mammal collections of the Bronx Zoo.

"Some that we have observed are dogs, gorillas and bears," she said.

The mechanism of snoring in these mammals probably resembles what happens in people. In human beings, according to The American Medical Association Encyclopedia of Medicine (Random House), snoring is noisy breathing through the open mouth produced by vibration of the soft palate, the back part of the separation between the oral and nasal cavities. It is more common while people are sleeping on the back, as the lower jaw tends to drop open. Snoring is caused by anything that hinders breathing through the nose. Gnats

Evolution sometimes 'picks' traits that don't seem to make sense to us for a variety of reasons -- for example, they may be a side effect of some positive trait or may increase herd health overall. For example, you may think that sleep itself should also be eliminated by evolution at some point simply because laying about in the wild unconscious is certainly the easiest way to become lunch -- however, the positive impact of sleep probably makes it worth it. There are other examples, like take homosexual animals and humans, which seem to be in a number of populations, despite obvious limitations on reproduction. And of course, evolution isn't finished, and never will be finished, so that there are current 'issues' with current models is to be expected.  ;-)

(You might point out that animals in the zoo don't face evolutionary pressures either, so that's why they snored, but I would assume that gorillas and bears have been captive for a small enough number of generations to not have evolved in any major way. Another thought: maybe if bears and humans and gorillas and dogs (former wolves) snore, it could be a sign that only the animals least prone to becoming the lunch of other predators have the evolutionary leeway to get away with snoring -- could be an interesting theory. "Origins of the snoring species." ) --Quasipalm 16:48, 22 October 2005 (UTC)

Dogs have been selected by human for thousands of years. Some dogs now look so unnatural that they cannot survive in the wild for a day. Since a dog breeds in a couple of years from birth, the evolution or devolution of its anti-snoring features can be several times faster than us humans.

Bears and gorillas are on the top of the food chain. Maybe they do not afraid to be eaten by all these lovely rabbits and hamsters at night. Maybe, I guess.

As to the majority of animals that are much smaller than humans, I guess they don't snore because their breathing is less of a problem. And as to the other ones much larger than us, maybe their soft palates are much thicker and vibrate at much much lower frequencies.

Do some bigger chimpanzees snore? Do some bigger orangutans snore?

Did these long-neck sauropod dinosaurs snore? Did the fattest T.rex snore? Survival the fattest! -- Toytoy 19:56, 22 October 2005 (UTC)

How do dogs recognize each other?

File:SW3vader.png

Sob! My dog will never recognize me again! George Lucas go to hell!

Dogs of different breed can be very different from each other. How does a Dalmatian recognize a Chihuahua?

Humans are not dogs. How does a dog recognize humans? A person can wear a red T-shirt today, a black tuxedo tomorrow. How does a dog (color blind) learn to disregard some but not all visual signals? How many house pets can recognize their owners if the clothing, smell (perfune) and facial features (shaved or not; hair cut; cosmetic makeup; eye glasses) changes? Can a guinea pig does that? Can David Prowse's dog recognize him if he wears the Darth Vader suit? -- Toytoy 10:53, 22 October 2005 (UTC)

Dogs recognize other dogs as dogs because they smell of dog. Smell is much more important than sight to a dog. Shantavira 16:12, 22 October 2005 (UTC)

Dogs have been selected by human for the past thousands of years. How did they manage to keep all these intercanine communication protocols? I mean you breed a new kind of dog based on its human usable features (look, ability to hunt, alertness ...). Maybe by some God-initiated accident, the best retriever in the world may smell like a cat! What a tragedy! I mean a dog that does not smell OK to the "Head Beagle" survives if it helps its owner make or save money. How can a dog intelligently designed in Yorkshire and another one intelligently designed in Beijing know each other? -- Toytoy 20:11, 22 October 2005 (UTC)

OK, a dog owned and bred by human still needs to have sex with another dog to beget puppies. Maybe this partially explains my question. If no other dog wants to have sex with your blue-ribbon retriever, you cannot breed it. No dog wants to have sex with your lousy gold medal. No way. They have to smell each other's anal gland so they can have sex.

What will happen if we perform artificial insemination on dogs? Will they lose the ability to recognize other dogs one day? -- Toytoy 20:25, 22 October 2005 (UTC)

If we eliminate the last threads of survival of the fittest, and instead cause all dogs to reproduce, this will eventually lead to degradation of the species to a level where they lose many abilities, including the abiity to smell. Purebred dogs already have many health problems, such as hip displasia, as a result of breeding. Salmon in fisheries were bred by the fish equivalent of artificial insemination (cutting them open to mix the eggs and milt) and suffered a rather alarming degradation of the species as a result. StuRat 20:58, 22 October 2005 (UTC)

I think basic reproductive functions will still be there. You still need to form good-enough sperms and eggs. And with mammalian animals, a female needs to have a working uterus even if you perform cesarean section in the end.

I always believe today's people have more inherited diseases than their ancestors. Maybe one day, many people will have degraded eyes and some other degraded complex organs. -- Toytoy 21:40, 22 October 2005 (UTC)

I heard some where that a dog can recognise more smells than we can recognise colours, for example, if two colours of red were so close we couldn't tell the difference, if those reds were smells, a dog could tell the difference.--Eye 19:23, 22 October 2005 (UTC)

I live on the 4th floor and my dog can notice my arrival at about the time I enter my apartment silently. Sound of footsteps can be a clue. I just don't know which senses they use and which ones they exclude. How do animals know a human changes clothing and makeup everyday so if one person's torso looks much darker than he/she was 2 minutes ago, that's still OK? I guess high intelligent social animals know their owners better.

Pets can learn, to some extent. The first time you came home wearing a bear suit, they likely would be rather frightened until they identified your voice and smell. However, the next time they would know that is within the range of clothing you wear. Pets also tend to think their image in a mirror is another animal, the first time they see it. After a while, they know better.StuRat 20:58, 22 October 2005 (UTC)

Do pets other than cats and dogs (hamster, chicken, snake, horse ...) recognize owners so well? -- Toytoy 19:39, 22 October 2005 (UTC)

Intelligent animals like a horse, pig, or parrot, yes. Stupid animals like a fish or chicken, no. StuRat 21:02, 22 October 2005 (UTC)

I think the "Human Recognition Algorithms" used by dolphins must be different from the ones used by dogs. Maybe a scientist can intelligently design a human dress code to fool 90% of dolphines, 10% of dogs and 100% of people and another to fool 10% of dolphins, 90% of dogs and still 100% of people. -- Toytoy 21:23, 22 October 2005 (UTC)

Most animals know who feeds them. A lady with long blonde hair feeds red kites in Wales. The only other people who can feed them are people with long blonde hair, (or blonde wigs)--Eye 20:06, 22 October 2005 (UTC)

To my original suggestion I would add that instinct is a very strong motivation, probably the only motivation in lower animals. When a dog sees anything trotting down the street on four legs its instinct is to investigate to see if it can have sex with it, chase it, sniff it, fight it, or play with it. It probably doesn't have a concept of "dog" but responds to it instinctually according its reaction to its smell and behaviour. Also dogs tend not to be too fussy what they have sex with. A dog is clearly shown "shagging the cat" in one episode of The Osbournes. Shantavira 10:15, 23 October 2005 (UTC)

I was always curious about a similar question -- how do humans recognize one golden retriever out of many golden retrievers?  :-) --I am not good at running 18:17, 29 October 2005 (UTC)

Windows XP log on screen

Ages ago when I was messing around with the computer at my parents' house trying to do something that doesn't need going into here, I somehow lumbered it with starting up with the Windows XP network long-on screen every time it boots up, even though the computer isn't connected to a network. There's no password set so it can be quickly gotten rid of my hitting the enter key, but it's still an irritant, and for the life me me I can't work out how to get rid of it. I've tried all sorts of things in the control panel and so forth, and Windows online help is sod all use. Can anybody help with this one? I'd be much obliged if so. Angmering 10:47, 22 October 2005 (UTC)

Maybe turn on the "Welcome" screen under User accounts? I don't know if you can do that under XP Professional, but you definitely can on Home Edition. Although I suppose it would still require you to click the name on the Welcome screen to get on to the computer. You could try reinstalling Windows XP, but maybe you should try get some other help before doing that. I don't know an exact way to get rid of it, but there must be some value in the Registry that toggles on and off automatic logon. Does anyone know that? Alternatively, use a Linux distro as your operating system instead. -- Daverocks 12:42, 22 October 2005 (UTC)

Help identifying frog photo

A Green Tree Frog, Hyla cinerea?

This morning, I saw a frog on one of my sliding glass windows. I took a bunch of pictures of it. Can anyone help me identify which frog breed it was so I can upload the batch to the Commons? This picture was taken in south Florida (north Palm Beach County). Neutrality^talk 15:31, 22 October 2005 (UTC)

Green Treefrog [58] (hyla cinerea) according to the UF website [59]. Dominick ^(ŤαĿĶ) 15:39, 22 October 2005 (UTC)

Thanks! Neutrality^talk 16:03, 22 October 2005 (UTC)

I wish I lived in a place where I could see such a creature on my window. :-( --Eye 16:54, 22 October 2005 (UTC)

Frog, Part II

OK, I wrote an article on American green tree frog. Two requests:

• First, can someone tell me the full name of "Schneider," who apparently first described and classified the species in 1792?
• Second, can somebody fix the taxobox in the article? Something messed up and now the entire article is in the taxobox!

--Neutrality^talk 18:49, 22 October 2005 (UTC)

Fixed. He was Johann Gottlob Schneider. Gdr 19:21, 22 October 2005 (UTC)

Nice job! Dominick ^(ŤαĿĶ) 14:45, 23 October 2005 (UTC)

Thanks, Gdr! Neutrality^talk 21:20, 23 October 2005 (UTC)

Saliva Spray

Does anyone know what it's called when saliva sprays from underneath your tongue toward the back of your mouth? I've never heard of this spoken of, but have experienced it, as has at least one other member of my family. Theshibboleth 16:29, 22 October 2005 (UTC)

In America, this can be called "gleeking" or "gleek." [60] It may be called something else too, and I'm not sure if it's slang. I suppose the formal way of saying it might just be "salivate," or "projectile salivation."  ;-) --Quasipalm 17:05, 22 October 2005 (UTC)

I wonder if there's a photo in the commons of someone doing a saliva spray.--Commander Keane 17:21, 22 October 2005 (UTC)

I have seen such a photo. It was published around 1972 in an anatomy text for medical students (Becker maybe?). Unfortunately not something we can use here. alteripse 04:28, 23 October 2005 (UTC)

To my knowledge, there is no formal word to designate the forceful ejection of saliva from under the tongue (I cannot exclude the possibility that a slang word exists). The phenomenon results from the compression of the ducts of the sublingual and the submandibular salivary glands by the muscles of the floor of the mouth, such as the mylohyoid, the digastric and the genioglossus, which cause a rapid expulsion of the ductal contents. By the way, the saliva is usually projected forward and upward, rather than toward the back of the mouth. I have been sprayed by my patients in this way on several occasions... --
Mark Bornfeld DDS
dentaltwins.com
Brooklyn, NY 18:29, 28 October 2005 (UTC)

Nicotine

For years, I've been told that nicotine can stunt the body's growth. Is this a fact? Thanks, Dave.

I'm not actually sure, however, nicotine and smoking do cause bloodvessels to narrow, inhibiting the supply of blood throughout the body. This can certainly cause problems with growth, though that would hardly be the most pronounced effect on the body. -- Ec5618 17:44, 22 October 2005 (UTC)

• I suppose it could retard your production of NAD+ and thus might have some effect on lipidbiosynthesis, and hormone regulation, but then I don't know how your body deals with pure nicotine--4.237.23.16 18:19, 22 October 2005 (UTC)

Elementary biochemistry error here. The problem with this speculation is that it forgets the difference between signal effects and metabolite effects. Nicotine is a signal molecule, like hormones and neurotransmitters. All of its effects result from this and the needed amount for this type of effect is tiny. On the other hand, for a metabolite to competitively interfere with a basic metabolic process that occurs in multiple forms in most cell systems, requires order of magnitude higher tissue concentrations (far more than can be delivered by your basic nicotine delivery device). The names should not be so similar because it tempts the novice into this confusion. Furthermore, a large proportion of the adverse effects of smoking are not attributable to the nicotine-- the nicotine is just the reward that perpetuates the addiction but is only a small fraction of the substances ingested. alteripse 15:24, 23 October 2005 (UTC)

Cigarette smoking can stunt your growth if your mother does it, before or after you are born. The evidence for mild prenatal stunting is strong, the evidence for postnatal (i.e., secondhand smoke effects) weaker. Unless you are idiot enough to turn mild asthma into severe by heavy smoking in early teens, your own smoking won't affect the last couple of years of remaining growth. Although most smokers start as children, most of the adverse systemic effects that might interfere with growth take several years to accumulate.alteripse 04:30, 23 October 2005 (UTC)

T-Rex

In the article on Tyrannosaurus rex, I'd like to include the number of T-rex fossils (incomplete or otherwise) ever found. Does anyone have a reputable, current source? -- Ec5618 18:10, 22 October 2005 (UTC)

Maybe you could visit your local university and check out paleontology journals, like The Paleontological Society and JOURNAL OF DINOSAUR PALEONTOLOGY. You may also find access to some of them online. --Quasipalm 01:11, 23 October 2005 (UTC)

Museum Victoria says "there are now parts of more than twenty-one individuals known from western USA". T. rex fossils are also found in Canada; National Geographic magazine comments on "the wealth of T. rex fossils already found—more than 30 to date". Gdr 09:51, 23 October 2005 (UTC)

Good to the Last Drop? or is it?

Is maxwell house coffee considered instant coffee, or just bad coffee?--4.237.23.16 18:21, 22 October 2005 (UTC)

It is one of several brands of instant coffee, a beverage derived from, but really quite different from, coffee. Plenty of people buy it, so it can't be that bad. Not to my taste though. Shantavira 18:27, 22 October 2005 (UTC)

Maxwell House makes both instant and regular coffee: [61] — File:Ontario trillium sig.pngmendel ☎ 05:45, 23 October 2005 (UTC)

You'll never get the answer to the question "Is MH considered .. bad coffee" here or anywhere else. There is no answer that would satisfy everybody, and there is no final arbiter of the truth when it comes to personal taste. If a person doesn't like it, the only truthful statement about that circumstance is "He doesn't like it". JackofOz 11:46, 23 October 2005 (UTC)

How calculators work

I was wondering if someone could explain to me how calculators work. I have looked all over the internet and I can't find anything. The Wikipedia article on calculators doesn't explain how they work, and its not on howstuffworks.com. Madsci.org has a page about it but it's written for a child and not very detailed. Thanks. --Taylor

• It rather depends on what level you want it described. Nowadays, the simple type of calculator is a small, dedicated computer, with no external RAM, just a dedicated CPU (a simple one, nothing much more than an ALU), probably a built-in ROM containing its control program, and an interface to the display and keypad. (More complex calculators with programmability etc., will have external RAM and are in effect small general-purpose computers). If you read up on how a CPU works, that will cover just about everything. In the past, calculators were probably made from digital logic chips, but CPUs are so cheap now I doubt that's cost effective. --Bob Mellish 19:57, 22 October 2005 (UTC)

What are the differences between a $0.75-cheap solar-powered giveaway calculator and a low-end engineer calculator today? Do they use the same core chip? I guess it could be cost-efficient to manufacture a general-purpose calculator chip based on 6502 or Z80 than to manufacture two or more.

Does a dirt-cheap calculator use a floating point-based number format internally? Or does it use fixed-point arithmetic? Do they follow IEEE standards (e.g. IEEE floating-point standard)? Maybe not, I guess. These old CPUs only have integer ALUs (+ and – only). So you write your own floating- or fixed-point programs with or without following standards. -- Toytoy 21:02, 22 October 2005 (UTC)

A common project used to be design an ASMD calculator, where the student would create the spec, and some of the logic. IIRC, the math details were not specified as part of the project. In any calculator, the implementation varies, and it can be anything from a processor, to a FPGA or a PLD. I usually use a simple test to evaluate designs, many fail this test, including the MS windows calculator in basic mode. Type 1+2*3 the correct answer is 7 if the calculator uses order of operations correctly, the incorrect answer is 9, this means the calculator evaluated (1+2)*3. Most calculators don't tell you the internal float format, and you shouldn't care. If you really need to know, like for astronomical calculation, then you should not be using a pocket calculator. Dominick ^(ŤαĿĶ) 11:38, 23 October 2005 (UTC)

I guess if you want to mass produce something cheaply, you will not use FPGA or PLD, will you? There must be some widely used generic calculator chips. -- Toytoy 16:20, 23 October 2005 (UTC)

Kangaroos

Do male kangaroos have pouches or is it just the females? If so why?

This is like the "men's nipples" question that has been discussed recently. A pouch is more costly than nipples on a male kangaroo. But if without it on a female kangaroo, it will be a disaster. I don't own a male kangaroo so I cannot answer your question directly. But I guess the answer is yes. As you know, animals were designed by an intelligent but inexperienced designer who did not spend a couple of minutes to undesign men's nipples and male kangaroos' pouches. God, someone please teach that lousy designer a biological lesson! -- Toytoy 21:10, 22 October 2005 (UTC)

A pouch on a male kangaroo would be a disaster as well because they rip at each others bellies when they fight. Is there an aussi amongst us who could settle the question?--Eye 21:25, 22 October 2005 (UTC)

Who needs an aussie when you've got an encyclopedia? Our article on marsupials begins, "Marsupials are mammals in which the female typically has a pouch." (Boy, it's hard to read articles on marsupial or monotreme reproduction without wondering if the articles have been vandalized. Strange critters.) Of course the trivial answer to why only the females have pouches is "because that's how they evolved", but it might help to note that the primary sexual characteristics of mammals tend to be unique to one sex. — File:Ontario trillium sig.pngmendel ☎ 05:36, 23 October 2005 (UTC)

Pages per Minute

When a printer says '15 pages per minute' or whatever, what is it printing? Certainly, I can never get more than 7 pages of normal quality text or 1 or 2 pages of photos from a printer in that time. smurrayinchester^{(User), (Talk)} 20:57, 22 October 2005 (UTC)

I once read that the PPM measurement is based on a 10% page coverage. It might have been 15% or 20% or even 5% - I can't remember the exact figure – but it's a ridiculously small amount, particularly when dealing with photos. --Pidgeot (t) (c) (e) 00:43, 23 October 2005 (UTC)

When they state "X PPM", look for the fine print elsewhere on the page that specifies the conditions under which the test was conducted :)--inks^T 04:02, 23 October 2005 (UTC)

Such figures are indeed usually about printing pages with a low coverage (meaning the percentage of the page that gets ink on it) – 10% would be text with plenty of open lines. And it will also normally refer to the fastest printing option with low quality. 4 seconds per page doesn't sound too strange for a modern printer. Mine approaches that. The problem with these figures is that they're only about one little aspect and between printers it's not even standardised, so they don't even serve for a comparison. Best ignore them. It's just the company showing off with useless info. DirkvdM 18:52, 24 October 2005 (UTC)

October 23

Recent Mergers

I would like to know a large merger that happened in the last 6 months. I mean a really big merger between two well-known companies. If it made news in the NY Times or a large newsource, that would be good. The reason is simple: there aren't any. I can think of plenty of large car company hybrids, but no large mergers between banks, auto companies, anything these days. Name one and I'd be happy to read it.

Symantec merged with Veritas, in the single largest merger of software companies to date. The original intention to merge was announced in December 2004, but the actual merger took place in July 2005, after regulatory approval. See List of Symantec acquisitions.-gadfium 03:59, 23 October 2005 (UTC)

US Airways acquired America West Airlines -Drdisque 03:58, 23 October 2005 (UTC)

To be honest, I only wanted to answer my homework. It's a shame I didn't get more answers though. Let this be a lesson. If you want homework answers, ask for them well.00:18, 26 October 2005 (UTC)

Why?

I reformatted by computer, now for some reason my computer no longer has the right codec to play .WMV files?? How can this happen? Shouldn't the one codec a clean restore leaves you with be the windows media format?! I mean, isn't that odd? how can I get it back?Thank you for helping me--help me 03:51, 23 October 2005 (UTC)

Even some types of .WMV files need external codecs to play. Before you formatted, you may have had the popular ffdshow codec. If installing that doesn't solve your problem, try using DivX. However, it's more likely that ffdshow will solve your problem. -- Daverocks 08:46, 23 October 2005 (UTC)

I would suggest downloading VLC media player -- it's built with a ton of codecs built into the system so you don't have to worry about not having the right one or downloading new ones. --Quasipalm 14:19, 23 October 2005 (UTC)

I second Daverocks. To elaborate on his comment: Just like for an .AVI file or a QuickTime file, a .WMV file may have been encoded with any video codec. The fact that it has a .WMV suffix doesn't necessarily mean it was encoded with any particular codec. Some mad scientist at Intel may be encoding video right now with an exotic codec he wrote himself, and the files he's generating are .WMV files. Then embedded within the .WMV file, there's an indication of which video codec was used. When you do a regular install of Windows Media Player, you get a collection of codecs that Microsoft wrote or has licensed, but some other popular codecs are not included, most notably Divx. Tempshill 03:00, 24 October 2005 (UTC)

Why do women wants unproportional breasts?

I am puzzled, why some women like to enlarge their breasts so big that it looks unproportional? I think natural is better.

As a counter-balance to their huge, Jennifer Lopez butts they got from the last surgery ? StuRat 18:27, 30 October 2005 (UTC)

It's a cultural thing, particularly in the United States. I think it might be less common than it was a decade ago. See Breast implant#Risks and controversy.-gadfium 05:09, 23 October 2005 (UTC)

A few years ago I heard that plastic surgery in the USA is usually enlargement, whereas in France it's usually to make them smaller, so that would indeed make it a cultural thing. I also suppose it's about what women think men want and that might be influenced by porn movies and such, which represent fantasies that men would not want to encounter in real life. Or maybe the movie makers get it wrong too, leaving the men with little choice. DirkvdM 19:05, 24 October 2005 (UTC)

I'm somewhat dubious about the claims that breast surgery in France is for making them smaller, though I think that breast implants are less popular in France than in the US. David.Monniaux 18:14, 30 October 2005 (UTC)

XXXXXXXXXXXXXXXXXXXXXXXXXL-sized breasts is a small but existent market. If you want to please ordinary people, you need a B-cup, C-cup or, at most, an E-cup. Most of us has a taste of regular-sized breasts. An A-cup is not a bad idea even if you work for the adult entertainment industry. Many people enjoy A-cups. However, there are some people whose taste of breasts cannot be satisfied with any sized breasts. They ask for breasts of unlimited sizes. That's probably why some porn stars began their unnatural and unhealthy boobs arms race.

Not only some men are crazy for over-sized breasts, some women are too. It's like having the biggest, baddest and loudest car of this planet. People really don't need it but some people do want it badly. I guess when a porn star gets a boost in her boobs, many other porn stars sharing the same niche want to upgrade theirs too because they need to please the few customers. However, I loath to see these porns so I cannot give you a real world example other than this generalized theoretical analysis. I can be dead wrong. The truth can be more interesting.

By the way, I have seen a Japanese web clip that displays breasts from A-cup to Z-cup to the tune of the Alphabet song: "A, B, C, D, E, F, G, ..." That's @#$%ing crazy. -- Toytoy 12:45, 25 October 2005 (UTC)

I notice we have a Human penis size article but not a Human breast size article! Who wants to volunteer to attempt collecting images? -- Chuq 04:02, 30 October 2005 (UTC)

"Women who are so concerned about their small breast size that they end up having surgery are just making mountains out of mole-hills." – Three's Company StuRat 18:27, 30 October 2005 (UTC)

How do male kangaroos urinate?

From marsupial:

Males usually have a two-pronged penis which corresponds to the females' two vaginas.

I don't think there are too many Aussie porn movies created for their marsupian population. How do these animals piss?

I really don't know anything about these strange creatures. Just 10 minutes ago, I thought Joey is a man who sells hot dogs at a street corner. -- Toytoy 05:54, 23 October 2005 (UTC)

Twice as efficiently? I guess "aim" is not important to a kangaroo. However "two-pronged" is a little suspect. Please see these delightful pictures of single-pronged kangaroo penises. Shantavira 10:44, 23 October 2005 (UTC)

Great pics! Do we have an article on kangaroo penis to put them in? alteripse 15:16, 23 October 2005 (UTC)

Marsupials have a cloaca [62] [63] that is connected to a urogenital sac in both sexes. Waste is stored there before expulsion. Urine does not exit through the forked penis. Dominick ^(ŤαĿĶ) 20:15, 23 October 2005 (UTC)

Quantifying universal indicator paper.

Does anybody know if you can quantify the use of universal indicator paper. I have thought about putting the paper through a spectrophotometer to get a quantitive result; but is this the best way to go about quantifying this data. I have also considered the use of a pH meter but dismissed this route.

If possible, use a pH meter. It's easier.

Otherwise, you may want to use a drop of Universal Indicator without the paper part. If you cannot buy it, prepare it by yourself. It's more difficult to obtain a good reading from light reflected from paper. You can take the absorption spectrum of that drop of indicator. You also need to calibrate your system. Personally, I think calibration is a difficult job because external factors such as temperature and other impurities can affect the color of that drop of indicator. -- Toytoy 10:32, 23 October 2005 (UTC)

Exactly. The whole point of indicator paper is just to give you an approximation of the pH of a solution. If you need anything accurate a pH meter is the way to go. -- Rune Welsh | ταλκ | Esperanza 13:33, 23 October 2005 (UTC)

*shudder* - there are things much, much, much better than pH meters – the fact that you mentioned a spectrophotometer makes me wonder whether this is for a paper or such? How accurate do you need the result to be? --HappyCamper 14:52, 23 October 2005 (UTC)

In answer to the above question from "Happy Camper" I just need a way of quantifing my results from Universal indicator paper. Will the spectrophotometer work with just the paper.?? By reflecting the light or something to that extent off the paper.

Ah, I see what you are looking for. Well, check out spectrophotometer and analytical chemistry. From the first article, it says "Perhaps the most common application of spectrophotometers is the measurement of light absorption, but they can be designed to measure diffuse or specular reflectance." Hmm...I wonder...If you use one of these machines, would you mind taking a picture of it and donating it to Wikipedia, provided that it is compliant with the GFDL? :-) --HappyCamper 00:12, 24 October 2005 (UTC)

I think if you work for a paint company you need to measure diffuse or specular reflectance everyday. -- Toytoy 14:04, 24 October 2005 (UTC)

Street lamps' color

Why are street lights generally orange colored? I've heard that they increase visibility, are cheaper to produce, and that they attract fewer bugs -- but I have no idea which of these are true (if any). --Quasipalm 15:26, 23 October 2005 (UTC)

I think it might have more to do with running (electricity) costs rather than detracting bugs. In the Sodium vapor section of the History of street lighting in the United States article, it says that the sodium vapor lamps use the least amount of power compared ot other types. Street light also has a bit of info. --Commander Keane 15:53, 23 October 2005 (UTC)

Just in case you don't know, the color of street lamps is based on the gas contained within the lamps. They aren't intentionally colored with colored glass, if that's what you were thinking. StuRat 17:41, 23 October 2005 (UTC)

Last time I visit Los Angeles, I found they don't switch off street lamps at noon! (Outside the LAX airport.) If they only switch on lamps when it's dark, it'll save some money. -- Toytoy 16:24, 23 October 2005 (UTC)

Some lights are on timers and others are on photoelectric cells that turn them on when it gets dark. Both systems can fail, however, and I suspect that's what happened in LA-X. StuRat 17:41, 23 October 2005 (UTC)

The chief (and probably only) virtue of sodium vapor lights is the energy efficiency. They actually create problems with visibility due to the unnatural color; our eyes are evolved to work best with white light, as from the sun. Because of this, there is a movement now toward metal halide lamps.--Pharos 18:18, 23 October 2005 (UTC)

Several yeras ago, many cities on Southern California went around covering every other street lamp on every street with black plastic, so the sensors didn't detect that it was becoming night, and turn on. The idea was to reduce the cost of running all of the lamps every night. But through the years, the black plastic has deteriorated and now hangs in shreds and all of the lights come in at night anyway. I always wondered why covering the sensors with black plastic didn't make the sensors think it was perpetual night, and cause them to burn all the time, but apparently it didn't. User:Zoe|^(talk) 20:49, 23 October 2005 (UTC)

Agree with Pharos -- the yellow streetlamps are sodium lamps, chosen for their efficiency, in places where you don't need to recognise colours. I seem to recall using a sodium lamp in a high-school physics experiment for something, presumably because it transmits only a narrow band of that yellow colour (when it's warmed up; they're pink/red when cold) Ojw 22:01, 23 October 2005 (UTC)

I remember one time I had gone to a concert in San Francisco with some friends, and had parked in a parking garage. It was late at night when the show ended. We went to go find my car. We walked around the garage several times without finding the car, and for a while we were afraid it had been stolen… But who would steal a cheap Suzuki Swift? Eventually, we found it, and also why we had trouble noticing it before; the fiercely orange light of the parking garage was making my red car look purple! Garrett Albright 04:09, 24 October 2005 (UTC)

What is food transfer?

Well, it's the transfer of food between two places. A quick googling shows that food transfer is used as a term in the food and beverage industry for "food transfer equipment" (such as tubing for beverages) and also in the term "regurgitative food transfer" about how some animals vomit food to share it with other animals in their herd. --Quasipalm 18:12, 23 October 2005 (UTC)

Settle a bet – about a freezer

In the long run, is it more energy efficient to keep a freezer empty or full? Jooler 20:17, 23 October 2005 (UTC)

If you were to never open it, there would be no difference, since the flow of heat into the freeser depends only on the difference of temperatures between the inside and the outside, the surface area of the freezer, and its thermal conductivity. However, if you were to open it, I'd say that an empty freezer would have more of the cold air inside replaced with warm air than the full freezer, so the extra warm air would need to be cooled down. The warm air in the empty freezer would have negligible thermal capacitance relative to the walls, and the heat loss would be unaffected. The cooling of this extra air would require energy, so the full freezer would have a slightly lower consumption of energy and thus be more "efficient" (as in usage of energy per unit of time). --Borbrav 21:30, 23 October 2005 (UTC)

I disagree. If you have a lot of stuff in your freezer, once it all warms up it'll take a lot more energy to cool it because it has a lot more mass. -- SCZenz 21:36, 23 October 2005 (UTC)

But then you don't normally keep your freezer open for the time it takes to cool down the actual items in the freezer. --Borbrav 21:41, 23 October 2005 (UTC)

I suppose the heat capacity of the air is negligible to that of any solid item in the freezer. Also, to just halve the amount of air you'd really have to stuff the freezer (if you still want to be able to access anything in a practical way). So the amount of air seems irrelevant. And I can't think of another factor off hand, so I'd say there's no difference worth mentioning. DirkvdM 19:17, 24 October 2005 (UTC)

In the very long run, much of your foods exposed to air will oxidize. As a result, a full refrigerator will be less energy efficient. However, it is totally unworthy to keep an empty freezer running. So if you count the benefit to people, an empty but running freezer is a waste no matter how high the energy efficiency is. -- Toytoy 14:23, 25 October 2005 (UTC)

Neodymium ions

Are there any ions in neodymium if so what is its most common? Thank You Dennis S

Have you looked at our Neodymium article? -- SCZenz 20:14, 23 October 2005 (UTC)

Info on boron

I am doing a paper on Boron for humans. Would like an y relevent info. Joe Cambell

Boron as trace element for human diet? As a therapeutic agent? As a useful element for making things for humans? alteripse 21:21, 23 October 2005 (UTC)

Try Boron. Dominick ^(ŤαĿĶ) 21:24, 23 October 2005 (UTC)

See Boron#Applications and Boron#Precautions. Neutrality^talk 21:32, 23 October 2005 (UTC)

Is it the paper or the Boron that is intended for human consumption? DJ Clayworth 20:23, 25 October 2005 (UTC)

Help identifying bird and plant species

Unknown bird species

Unknown bird species

Unknown gladiolus species

Unknown gladiolus species

Can somebody help identify this bird and gladiolus? And, if possible, it would be great if someone could touch up the photos (all I have is lousy Picasa). Neutrality^talk 21:31, 23 October 2005 (UTC)

Sandhill Crane (Grus canadensis) [64] Dominick ^(ŤαĿĶ) 21:43, 23 October 2005 (UTC)

Isn't that a common Bougainvillea? Dominick ^(ŤαĿĶ) 21:45, 23 October 2005 (UTC)

Oh, yes....you're quite right, I meant to say bougainvillea. Guess I'm not much of a botanist. ;) Neutrality^talk 21:48, 23 October 2005 (UTC)

Interesting distribution [65] IMHO, they are making a real presense in Florida. In the Ocala forest they are thick as thieves. They are also non-migratory[66]. Dominick ^(ŤαĿĶ) 23:18, 23 October 2005 (UTC)

October 24

alcohol

To what extent does alcohol cause brain damage?

• Have a look at the article Effects of alcohol on the body. -- Canley 01:39, 24 October 2005 (UTC)

reproductive organ

is it true that if you dont use it you will lose it--65.175.226.190 23:40, 23 October 2005 (UTC)

Wikipedia does not give medical advice →Raul654 23:41, 23 October 2005 (UTC)

Unscientifically, no organs have ever fallen off for disuse. People in general, never lose organs, unless they are detached in trama. Dominick ^(ŤαĿĶ) 00:02, 24 October 2005 (UTC)

I don't want to upset our inquirer, but haven't you ever heard of disuse atrophy? alteripse 01:25, 24 October 2005 (UTC)

Am I supposed to know what this is about? Maybe I haven't watched enough US adolescent movies :) . DirkvdM 19:22, 24 October 2005 (UTC)

Some would say that watching one is too many. :-) Dismas|^(talk) 07:49, 25 October 2005 (UTC)

Well, just to be sure, masturbate a lot and keep yourself covered :) ☢ Ҡieff⌇↯ 12:36, 25 October 2005 (UTC)

i think that is the answer he was hoping on. :) Boneyard 10:26, 26 October 2005 (UTC)

bases/acids to catalase

what will happen if bases/acids are added to catalase-containing materials? What will happen if hydrogen peroxide is next added?--172.199.133.7 04:24, 24 October 2005 (UTC)

In order to help you with your homework, I suggest you read the article on catalase as well as Base (chemistry) and Acid. Dismas|^(talk) 05:14, 24 October 2005 (UTC)

Making an unfair die fair

To make an unfair coin fair, one can use the following trick

If a coin is bias then it cannot be used as a fair coin. But if the rules of the game is changed to properly rely on when the coin gives a certain result, the coin can still be used to produce a fair result. John von Neumann gave the following procedure :

  1. Toss the coin twice. Note down the first "result" and the second "result".
  2. If the results match, start over, forgetting both results.
  3. If the results differ, use the first result, forgetting the second.

Note: This procedure only works if the tosses are paired properly. If part of a pair is reused in another pair, the fairness may be ruined.

My question is this:

Is there a way to make an unfair dice fair? Ohanian 06:16, 24 October 2005 (UTC)

The equivalent procedure, for an N-sided die, would be:

1. Roll the die N times; note each result.
2. If any of the results match, start over, forgetting previous rolls.
3. If all the die rolls are different, use the first result and forget the rest.

Obviously this is a very inefficient procedure. -- SCZenz 06:28, 24 October 2005 (UTC)

I'm impressed by this procedure. If I ever play dice with the devil, I'll insist on these rules.-gadfium 07:51, 24 October 2005 (UTC)

If I were the devil, I'll give you a die or a coin that's so unfair that it will never give you anything other than head or 1. Analysis:

• Possibility of H-H pair: 1*1=1
• Possibility of H-T pair: 1*0=0
• Possibility of T-H pair: 0*1=0
• Possibility of T-T pair: 0*0=0

(Proof for the die follows the same logic.)

You lose. I win. I am evil. Who cares about you? Don't think you can outsmart devil. -- Toytoy 13:54, 24 October 2005 (UTC)

Actually the devil never wins either because no valid results are ever generated. So it's down to who dies of bordeom first (not that that's very helpful, I guess). DJ Clayworth 20:21, 25 October 2005 (UTC)

Its actually called a die (singular) or dice (plural). This method would help to make an unfair die fair. -- Ec5618 08:00, 24 October 2005 (UTC)

Polya Frequency Distribution

I am trying to find details for the Polya Frequency distribution. They are referred to as PF_infinity, PF_2, etc. From what I recall they are some kind of limit or not a limit of the sum of exponentials. I can't find them on Wikipedia, or Google.

The bigger problem is that I need the sum of 2 independent exponentials with different parameters.

Regrds, Abhijit Roy

• Give this link a click at Wolfram Research

GFP

I need some information on the concerns regarding the effect GFP tags have on the behaviour of proteins, but searching for "concerns" "GFP-tagged protein" on Pubmed and Clusty only gets me experiments and papers where they were used.

Has anyone got an idea on how to refine my search, or can someone point me to a good resource on the subject. I've got the basic issues down, but I'd like to be more thourough. - 131.211.210.17 09:27, 24 October 2005 (UTC)

Don't use "concerns" in a scientific literature search. It is a reflection of your state of mind or valuation of something but the gap between denotative meaning and common connotative usage is too large to be a useful coding term. If you are concerned about actual risks, then search for "risk" as a term. If your concern is whether use distorts the function it is being used to measure, search for a general review of GFPs and scan for one from a methodology journal, and you should find a discussion of the issue. If neither of those is your "concern", I can't even guess and you will need to spell it out more plainly for us. alteripse 11:32, 24 October 2005 (UTC)

• That question was me. I was looking for iterature that discusses the effect the tagging has on the function of the proteins that are being studied. - Mgm|^(talk) 17:59, 24 October 2005 (UTC)

I don't know much about this particular method but would start by looking for some review articles about the method itself to see if there is a discussion of your question, which now makes sense to me: If you tag a protein to observe it, does that change the behavior of the protein in an important way? Sounds like a good question. I assume that early work on the method compared the results obtained by GFP tagging with results obtained by other methods. Have you looked at any of the more recent volumes of Methods in Enzymology if you can't find anything online? As a last resort, call or email someone who has written one of the reviews and ask if they know of any examples in which the method gave misleading results because the tagging interfered with the protein. alteripse 20:59, 24 October 2005 (UTC)

• I'll try if it works without another query. I need to have things as general as I can get them. Methods of Enzymology might work. Thanks for the ideas. - 131.211.210.17 07:49, 25 October 2005 (UTC)

Chemistry

why is the valence of alkali metals always 1?

The reason for this is because those elements have a single electron in their outer shell. When this electron is removed by a chemical reaction with an electron deficient element (like Chlorine) the element is more stable because the inner shell is filled.

Gas collection mechanism

First thanks for answering my earlier question on sun & planets gear & epicyclic gearing. This one is rather more theoretical. Is there at present any sort of semi-permeable material which would allow specific gasses (such as CO2 & Ozone) through into a balloon or other container but not let them out again. Would it be able to do this at normal pressure & therefore collect CO2 directly from the atmosphere, through some sort of osmosis or would some sort of pump be required to pump in air to the balloon & pump out all the air less the CO2. My reason for asking is that I had the thought of collecting CO2 in massive dirigibles/balloons & towing them to Mars to start off an atmosphere there. I also thought of taking gasses such as Ozone from a gas giant such as Neptune & towing them to earth to fill the hole over Antartica. I know we don't have the rocketry technology to do this right now but can we do the gas capture with current (or expected) technology? AllanHainey 13:56, 24 October 2005 (UTC)

Osmosis (which is just a special case of diffusion) only takes place from areas of high concentration to areas of low concentration. If you tried to construct such a balloon that was permeable only to carbon dioxide, you'd find that the diffusion would stop as soon as the concentration of CO₂ reached the same level as the outside air (i.e. thermodynamic equilibrium). That's not to say it can't be done, however, but it would require some kind of energy input—for example, continuously removing out the CO₂ to keep the diffusion going.

On the other hand, I believe other methods of gas separation are more commonly used and efficient. The standard method I learned in chemistry class uses refrigeration fractional distillation to separate the gases out according to their different boiling points. As for your idea about the ozone layer: the hole in the ozone layer is primarily caused by compounds like chlorofluorocarbons that break down ozone. If those chemicals are removed from the atmosphere, the ozone is naturally regenerated by ultraviolet light. Until that occurs, any other measures taken will probably be relatively ineffective. --David Wahler (talk) 17:04, 24 October 2005 (UTC)

You;d need one hell of a lot of CO2 to make a dent. Actually, if you'd construct rockets that produce CO2 as a waste product to use that, you'd probably need to send an amount of rockets that would cripple the economies of all countries in the world. I guess. Even if you'd collect all the waste CO2 in the Earths atmosphere (before it gets exhausted would seem most efficient) that wouldn't be enough because the climate change effect is largely caused by a small difference in consentration. I think. Hope my guessing and thinkng have helped any. DirkvdM 19:34, 24 October 2005 (UTC)

The chlorofluorcarbon effect on Ozone is still a matter for debate.

What this person wants is a one-way filter to filter out carbon dioxide, something where CO2 will only go through one direction. No such thing exists as far as I know. Simple mechanisms for capturing CO2 already exist one of the simplest is a lime-water solution which will react with CO2 int he air and then drop out of solution as CaCO3. Magnesium will also do this I think. The CO2 can then be released by heating or treating with acid. I presume carbonates exist on Mars, so only the last part of treating with acid would be needed. Ozone is trickier, it is not stable and breaks down into diatomic oxygen in a matter of hours, so your bag from Neptune would no longer be Ozone by the time you go it to Mars. Ozone can be created from Oxygen using an electrical discharge, but since it does not last very long you have to continually do it in large amounts.

Monomolecular blades

In the first book of Star Trek: The Lost Era, a weapon called a "monomolecular blade" is described. It's a knife or sword whose blade is only one molecule thick. It is described as being able to cut through practically anything – cloth, skin, bone, even solid steel – as if it were cutting through hot butter. Would this work in real life, and if so, why? — JIP | Talk 16:22, 24 October 2005 (UTC)

• It's a staple of science fiction that a molecular monofilament (essentially a wire that was one long molecule) would be able to cut through almost anything since its covalent bonds would be much stronger than the typical Van der Waals or ionic bonds that are the inter-molecular bonds in most things. A blade would be similar. However, I don't know how realistic this is in terms of numbers. --Bob Mellish 17:02, 24 October 2005 (UTC)

We could probably test this, by holding a carbon nanotube. If it falls through the hand, its true. -- Ec5618 19:30, 24 October 2005 (UTC)

If it is one molecule wide and many thick, you would find that in the diction of cutting it may be stiff, but the lateral stiffness of a sheet one molecule thick may be lacking, IMHO. Carbon nanotubes are not one molecule thick. As I recall, bayonets with serrations were especially deadly, to the point that during WWI if you were captured with one, you usually were going to die of your wounds, past or future. Clean cuts are not always as deadly. Dominick ^(ŤαĿĶ) 20:03, 24 October 2005 (UTC)

It was always my understanding that the serrations of which you speak weren't on the sharp side of the blade but on the back of the blade. The notches were cut so that they would tear at the organs/muscle/skin on the blade's way out of the wound it has just made. Therefore a surgeon would have a harder time sewing up the wound. That is if the person even made it to a surgeon considering the additional loss of blood caused by such a nasty wound. Dismas|^(talk) 07:47, 25 October 2005 (UTC)

"Carbon nanotubes are not one molecule thick" I beg to differ. Not only are they one molecule thick, they are one molecule long. Some double walled tubes have been made, which would technically still be a single molecule thick, and long.-- Ec5618 20:26, 24 October 2005 (UTC)

Ripping sound from an mpeg file

So I have an mpeg file and I want to pull the sound from it. Are there any free (gratis or libre) programs for Windows that can do this? I see some from googling, but none that I had any idea whether they were spyware free, which is important. If it matters what type of mpeg encoding, how do I tell which it is.? Related question, does anyone know similar software to rip the sound directly from a DVD? (short bits to qualify for fair use of course). Thanks – Taxman ^Talk 19:14, 24 October 2005 (UTC)

MPlayer (http://www.mplayermq.hu/) and VLC (http://videolan.org/vlc/) are two great open-source media players, and I'm pretty sure both of them have options to dump audio or video to another file. For MPlayer, one of the following command lines should extract the audio from just about any file:

mplayer -ao pcm filename
mplayer -dumpaudio filename

The former will decode the audio to a WAV file, while the latter will just demultiplex it from the video without decoding or altering it. For a DVD, I think you can use dvd://1 as the filename, but there might be additional options. VLC would probably be easier to use, as I believe it has a wizard or something for this, but I can't remember off the top of my head how to do it. Also, if you're on Linux, transcode is an option but I've found it to be a little less robust and more complex than the other two I mentioned. --David Wahler (talk) 19:57, 24 October 2005 (UTC)

Thanks, great tips. I didn't reallize mplayer ran on Windows too, or offered output streams like that. I'll play with those and see what I can get, and report back any problems. Thanks again – Taxman ^Talk 22:05, 24 October 2005 (UTC)

Light in a box nr 2

After the 'Light in a box' question above, Eye said I Like this kind of question. Think of another. Well, here's one I thought of as a kid when I learned about those one-way mirrors that are used in police interrogation rooms. If you'd make a sphere (stronger than a box) out of such a material light would build up inside until .... DirkvdM 19:40, 24 October 2005 (UTC)

Actually, such mirrors allow 50% of light to pass through to the other side, whichever side it comes from. So, 50% of incoming light would enter the sphere, 25% would come out the other side, 12,5% would come out the front, after reflecting, 6,25% would go out the back again. Pretty soon, all light would be lost.

Still, the basic premise is the premise behind lasers. A phased wave of light is continually reflected back and forth through a lasing medium. As the photons reflects they persuade energised molecules to transmit a photon, which follows the original photon, and have the same phase and direction. Finally, when enough power will have built up, the energy will be allowed to come out of the lasing medium on either side, creating the beam of light we all know and love. -- Ec5618 20:23, 24 October 2005 (UTC)

Those are partially transparent mirrors. The secret is that the "invisible" side has a lot less light than the other side, so most of this light is reflected and you can't see it, while plenty of light rays from the bright side pass. Light is partially reflected from both sides. So, I think the situation here wouldn't even be interesting, since all light inside the sphere would just go throught its walls eventually. ☢ Ҡieff⌇↯ 20:16, 24 October 2005 (UTC)

A light catcher. I like it. I feel a science fiction story comming on...The evil Lord of Darkness has stolen the Light Catcher because he who controls the light controls the universe....Ha! Ha! (evil laugh):-)--Eye 20:24, 24 October 2005 (UTC)

added after edit conflict:

Nope, sorry. One-way mirrors are actually completely symmetrical; they just appear one-way because the room on one side is much more brightly illuminated than the other. From the brightly lit side, the reflection of the room in the mirror is so much brighter than the light transmitted from the other side that it washes everything out. From the darker side, on the other hand, there's much less reflection and much more transmission. You can test this for yourself; go up to a "mirror" like this and put your eyes up close to it. If you use your hands to block out the ambient light, you'll be able to easily see through the mirror. So in answer to your question: any material that you could use to construct your sphere would let light out just as easily as it would allow it in.

It's actually one of the fundamental theorems of computer graphics that any path will transmit light equally in either direction; I'd give you more information, but I can't for the life of me remember the name of the law. I do remember that there was a relatively recent SIGGRAPH paper demonstrating it in an interesting way—they managed to set up a system where they could use a digital projector as a virtual camera, and vice versa. --David Wahler (talk) 20:24, 24 October 2005 (UTC)

• To clarify, a "one-way" mirror isn't actually "one-way" at all – it must (from thermodynamics arguments) let the same fraction of light go through one way as the other. If you flipped one back-to-front, it would work just the same way. --Bob Mellish 20:25, 24 October 2005 (UTC)

Hmmm, I could have thought of those things myself. Actually I now remember once seeing that 'coming up to the mirror with hands cupped around the eyes' thing in a film. Ah, well, another childhood fantasy gone to smithereens. Next you'll be telling me Sinterklaas doesn't exist .... DirkvdM 06:32, 25 October 2005 (UTC)

I think the existance of Sinterklaas has been pretty well established. Ask another .. ? -- Ec5618 06:40, 25 October 2005 (UTC)

Salt Ice Cream

How does salt lower the temperature of ice in one of those hand cranked ice cream tubs?--Eye 20:04, 24 October 2005 (UTC)

Does it? There are salts that, when allowed to mix or disolve, will react endothermically, causing the temperature to raise. I've heard of those being used to cool icepacks in medical kits, but never for icecream. I believe Ammonium chloride is an example. -- Ec5618 20:23, 24 October 2005 (UTC)

It doesn't. Salty water has a lower freezing point, so you can get liquid water below 0° C. Since liquid takes the shape of its container, this very cold, salty water gets in contact with a larger area than a bunch of ice cubes, so it freezes more efficiently. ☢ Ҡieff⌇↯ 20:19, 24 October 2005 (UTC)

The salt melts the water, since water has a heat of formation, the amount of energy needed to take water from liquid to solid at the same temperature, the energy to do this has to be taken from somewhere, so the temperature of the water lowers.

Spicy Foods

What is the best (fastest) way to get rid of the "hot" feeling in your mouth and/or throat when eating spicy foods such as jalapenos? (Jakz34 21:13, 24 October 2005 (UTC))

I favor eating absorbtive bread, though I think chemical bases like milk are also supposed to be effective. — Lomn | Talk / RfC 21:42, 24 October 2005 (UTC)

• I believe milk works because the spicy-tasting molecules (capsaicins) are soluble in fat, but not in water (which is why drinking water doesn't seem to quench the fire). Things like yoghurt also work for the same reason. Though serious curry eaters swear by beer, preferably lager, perhaps because of its well-known topical numbing effect. --Bob Mellish 21:56, 24 October 2005 (UTC)

• Yup, our capsaicin article lists those, but also comments they don't necessarily work. (And gives no references or justification either way). Maybe once you're pain sensors are pissed off at you, they don't calm down till some time after the actual irritant, capsaicin, is gone. But don't worry, the endorphin rush should make up for the pain for you. Sucking on ice cubes after eating something like buttered bread seems to help the most to me. The ice doesn't get rid of the pain any faster, but dulls it pretty well for as long as the ice is there and makes it livable until it actually goes away. - Taxman ^Talk 22:05, 24 October 2005 (UTC)
• Chinese food generally comes with krupuk (prawn crackers), does it not? These are included to clear the palette. -- Ec5618 21:58, 24 October 2005 (UTC)

In my opinion, celery does an excellent job neutralizing spicy foods. I suppose thats why they serve celery with Buffalo wings. - Cobra Ky (talk, contribs) 22:48, 24 October 2005 (UTC)

If the fat in milk and the cold of ice help, then shouldn't ice cream be a miracle solution? Hmmm, ice cream for desert after a curry? DirkvdM 08:04, 25 October 2005 (UTC)

Carbohydrates (bread, rice), dairy (milk, yoghurt) or alcohol all work, although individuals may get more milage from one or another. Trollderella 02:43, 27 October 2005 (UTC)

October 25

Earth

How fast does the earth spin around the sun? Name:Aidan Age:8

• Have you seen our article titled year?--inks^T 00:06, 25 October 2005 (UTC)

The earth circles the sun once a year, traveling at a velocity of roughly 27 000 000 000 000 000 000 000 miles per year, or about 74 000 000 000 000 000 000 miles a day, or about 3 000 000 000 000 000 000 miles an hour. The earth circles its own axis (spins on its axis) once a day, at an equatorial velocity of roughly 24,000 miles a day, or about 1,000 miles an hour. alteripse 00:10, 25 October 2005 (UTC)

Mmm, the speed of light is only 670,616,629 miles per hour, and nothing travels faster than this. The Earth article (and this website) say the Earth's speed around the sun is 30 km/s = 18.6 miles/s = 108000 km/h = 66960 miles/h.

OK, probably I shouldnt have done off the top of my head math. I was remembering 24,000 mi circumference, 93 million miles to sun (=radius of orbit), and pi r squared for the diameter of the orbit travelled in a year. Where did I make my mistake? I see, I think I used too many zeroes and squared 93 trillion rather than million, and the diameter is pi x r not pi r squared. That would do it, wouldnt it? 93 million x pi would be 292 million mi for orbital diameter in one year, or 800 000 mi per day, or 33 333 mi per hour. Now I agree within a factor of 2. Where is my mistake? alteripse 00:53, 25 October 2005 (UTC)

Circumference is 2πr, not πr. --David Wahler (talk) 00:58, 25 October 2005 (UTC)

Good thing I don't make a living doing this sort of thing. Thanks for cleaning up after me. alteripse 01:01, 25 October 2005 (UTC)

pi r squared will give you the area encompassed by the orbit of the earth. Since the orbit is not a perfect circle, neither calculation is 100% correct.

This question was asked, and answered, farther up the page. It's question #8. Dismas|^(talk) 07:38, 25 October 2005 (UTC)

Isn't there a Monty Python song about this? Trollderella 02:47, 27 October 2005 (UTC)

Dehydrohalogenation

Hello and thank you,sir,for answering my previous question.I now want to know about dehydrohalogenation.I read about this in an article about Pharmaceuticals. Please tell me what does it mean. Thank you.

Please search first. See Hydrohalogenation. The prefix de- suggests the reaction is reversed.

CH₃-CHBr-CH₃→CH₃-CH=CH₂ + HBr

Any other halogen could be used instead of the Br. -- Ec5618 06:48, 25 October 2005 (UTC)

Photograph Enhancements

Are those photograph enhancements (like finding out a cars number plate from a blurred picture) that they show in the TV shows and movies really possible, and if so, how do they work? --AMorris (talk)●(contribs) 08:55, 25 October 2005 (UTC)

Short answer: no. Longer answer: There are methods to make certain details clearer, by sharping and changing contrast, analyzing different color channels and manipulating them individually, etc etc. These are possible, but they're not miraculous. But, when you see on the movie someone zooming on a video, and a magic line crosses the screen revealing extra detail out of big pixels, well, no, that's just (mathematically) impossible. If the detail was not there, stored in the first place, you can't retrieve it out of nowhere. ☢ Ҡieff⌇↯ 09:47, 25 October 2005 (UTC)

No. Enhancement is basically filtering. Filtering allows us to increase contrast, for example, or to remove certain types of noise, which might make details that were previously impossible to see with the naked eye, visible. Filtering always means some data is lost, however.

Enhancent is also a very subjective concept, which means there could never be such a thing as an 'enhance image' option on your computer. -- Ec5618 09:07, 25 October 2005 (UTC)

In general, the incredible 'enhancement' you see on television and in movies is complete nonsense; it's a crutch for incompetent scriptwriters. It's worth noting that if you have access to more information than one image, it's sometimes possible to pull a bit more detail out of a frame. For instance, if you have a series of video frames of an object generated under specific conditions, it is sometimes possible to generate a combined image with more detail than any single still frame from the series. TenOfAllTrades(talk) 12:52, 25 October 2005 (UTC)

Further to this, there are some tricks that allow multiple images from different positions to be used to get an image that has far more detail than any of the single images. There was some discussion of this on the reference desk earlier. Nifty, but still not the magic enhancement button you're asking for...--Robert Merkel 14:21, 25 October 2005 (UTC)

Lots of tricks are possible if you HAVE ADDITIONAL INFORMATION. For example if you know a fuzzy image has to be 0-9,A-Z in a specific font (example: a Florida license plate) a computer can often resolve an otherwise unresolveable fuzzy image. WAS 4.250 02:20, 26 October 2005 (UTC)

You can often solve these problems the analog way. You can manufacture license plates of various numbers and alphabets such as A55ÕRGY and take pictures under recreated lighting condition. -- Toytoy 04:50, 26 October 2005 (UTC)

media

Do the media act as agents that reproduce social inequalities or are they the "glue" that binds society togather?

• Be specific – explain your question in detail if necessary, addressing exactly what you'd like answered. For information that changes from country to country (or from state to state), such as legal, fiscal or institutional matters, please specify the jurisdiction you're interested in.
• Do your own homework – if you need help with a specific part or concept of your homework, feel free to ask, but please do not post entire homework questions and expect us to give you the answers.
• Sign your question – type --~~~~ at its end. -- Ec5618 10:29, 25 October 2005 (UTC)

The answer to your question is 'yes'. Or, possibly, 'no'. It's almost certainly one of those, however. TenOfAllTrades(talk) 12:39, 25 October 2005 (UTC)

Hurricane Wilma

Why did hurricane Wilma move so slowly in the Gulf of Mexico, and then suddenly move quickly after it hit Florida? Is it because the water along the East Coast moves quicker? Or because of the jet stream? --216.191.200.1 12:56, 25 October 2005 (UTC)

While I'm not sure, you might like to read Tropical cyclone#Movement and track, which discusses cyclone movement. It states:

"Although tropical cyclones are large systems generating enormous energy, their movements over the earth's surface are often compared to that of leaves carried along by a stream. That is, large-scale winds—the streams in the earth's atmosphere—are responsible for moving and steering tropical cyclones." -- Ec5618 13:59, 25 October 2005 (UTC)

You may want to specifically ask User:E. Brown. He seems to like hurricanes. --Lord Voldemort ^{(Dark Mark)} 19:30, 25 October 2005 (UTC)

Finding positions of desktop icons under windows

Does anyone know where on windows the desktop icons positions are stored? I've been searching the registry without luck and I'd appreciate some help. --Andy

• Suggestion: get Regmon and/or Filemon, run them, and try moving the icons around. These program monitor any registry / file changes on a system, and are very useful. --Bob Mellish 16:13, 25 October 2005 (UTC)

Well, i tried the programs but they're hardly useful since there's too much stuff going on...--Andy

HKEY_CURRENT_USER\Software\Microsoft\Windows\Shell\Bags\1\Desktop [67] --Majts 21:20, 25 October 2005 (UTC)

Also this thread is interesting as it shows which key settings in that hive control things like auto arrange --Majts 21:34, 25 October 2005 (UTC)

Open source licenses

I have just developed a program that I want to release as open source with the source code.

• I want to retain all copyrights to the work.
• I want to let people modify/improve the code and release their improvements, but they cannot claim they wrote the original work or claim they own the copyright to it.
• Any messages/text that show me as the author and copyright holder must remain intact, and any modified versions not by me must be clearly marked as such.

I'm new to all this, so what would the best license be to use? --82.18.254.3 18:02, 25 October 2005 (UTC)

I would recommend you check out Creative Commons, as they work to help people identify specific licenses for their needs by asking the user for criteria such as yours. I recommend you check this, rather than giving a specific license, as the process may uncover additional criteria you've not yet considered. — Lomn | Talk / RfC 18:13, 25 October 2005 (UTC)

To clarify one of the subtler points you may not have thought of: Suppose somebody takes your code, makes some modifications to it and starts distributing it. Do you want to force them to distribute it under the same free license as well, or should they be able to set their own terms? This seems to be one of the most controversial aspects of different open source licenses these days.

The GPL takes the position that if the code is free, all the derivatives must be free and licensed under the same terms. The BSD license, on the other hand, lets others take the code and do whatever they like with it; this seems pretty close to what you're suggesting. I personally lean towards the BSD camp, since nothing anybody else does will affect my code one way or the other. However, it's a personal choice, and I can easily imagine why someone else might feel differently. Incidentally, Creative Commons licenses allow you to choose between these alternatives—you can optionally include what they call a "share alike" clause. --David Wahler (talk) 19:47, 25 October 2005 (UTC)

The major open source licenses are the BSD license, the GPL and the Mozilla Public License. Putting your code under BSD is almost like realeasing it into public domain except that you retain your copyright and modified code must display this copyright message. The GPL makes your requirements much more explicit (the license text is more that ten times as long), but also requires that any modfied version is licensed under the GPL. Depending on who you ask this will increase or decrease the freedom of your code. (Software that is licensed under the BSD license can be 'upgraded' to GPL, but GPL software cannot be 'downgraded' to BSD). The MPL adds some extra legal protections that are useful if you want to distribute a commercial version aside from an open source version. Personally, I license my code under the GPL. --R.Koot 21:57, 25 October 2005 (UTC)

Looking at your requirements, you retain the copyright to any code you write, regardless of the licence. Therefore, you can do anything you want with it, including reusing it as part of a proprietary product. So that part is irrelevant to your choice of licenses.

All of the major open source licenses (the GPL, BSD-style, and MPL as described by R. Koot) note that you retain your copyright to your original work, and require that anybody redistributing your work, or a modified version thereof, must retain your original copyright notice.

The GPL specifically requires that any modified version carry prominent notice of the modification (see section 2 of the license text). Most of the BSD-derived licenses do not have such a requirement explicitly. Instead, they have a requirement that the names of the authors not be used to promote the software unless further written permission is given. For instance, the XFree86 Project's license states the following:

Except as contained in this notice, the name of the XFree86 Project shall not be used in advertising or otherwise to promote the sale, use or other dealings in this Software without prior written authorization from the XFree86 Project.

If you wish, though, there's nothing stopping you from adding a specific clause to a BSD-style license that says any modified version must be marked as such. Such a license would still be an open source license.

Note that the GPL requires a number of other things of people who redistribute or modify your software beyond your requirements. It is up to you to decide whether you think these requirements are a good or a bad idea.

Hope this helps. --Robert Merkel 04:37, 26 October 2005 (UTC)

When I release things with a license, I like to use the Artistic License. It has a clause that states that other people can't sell your project for a profit, which was important to me -- in the off chance that someone is going to profit from my hacks, I want it to be me. Otherwise, it's a pretty short and loose license. With respect to Creative Commons, I think columnist John C Dvorak is a bit of a tool, but he makes some good points in this criticism of the system. Garrett Albright 14:46, 26 October 2005 (UTC)

If I may ask, what good points? The arguments Dvorak makes seem to apply to all free/open licenses, not just Creative Commons. In fact, his main problem with CC appears to be that "it seems to actually weaken the copyrights you have coming to you without Creative Commons. Oh, brother!" Ilmari Karonen 20:37, 26 October 2005 (UTC)

No joke. The guy's an idiot, at least on that article. He doesn't seem to have bothered to actually have read anything by Lessig (or any of ther other Free Software folks) and as such is completely clueless about the structure of the licenses, which are really not that complicated. "Why would anybody even want this? I'm totally confused! Professor Lessig must be a friggin' idiot!". Uh, right. --Fastfission 02:12, 27 October 2005 (UTC)

The fact that a license can stand on its own without the backing of a wealthy organization and a cutesy trendy logo, for one. Also, while Dvorak doesn't mention it, the fact that a CC license can vary from fairly restrictive to full-on public domain can be confusing. Garrett Albright 14:31, 27 October 2005 (UTC)

I don't know about you, but if I'm going to release my work under anything more restrictive than the BSD license, I'd rather like to have "the backing of a wealthy organization" behind it, whether that organization is CC or the FSF. After all, I hardly have the means to sue some big corporation if they violate the terms of my license. I don't know about CC, but the FSF at least seem to be more than happy to help. Cutesy trendy logos are completely optional, but nice enough. (As for the potentially confusing variety of CC licenses, I grant you that point. Not that Dvorak seems to get it, since he shows no indication in that article of being aware that there is more than one CC license.) Ilmari Karonen 17:31, 27 October 2005 (UTC)

seedless fruits

Where do the seeds go in seedless fruits, or, how do these fruits become seedless?(some grapes, watermelons,oranges etc.) Are there different methods or reasons for this? If so, what are they? Thanks! Hattie

There's a small amount of information in our article on fruit, but not much. Basically, seedlessness (also known as parthenocarpy is a natural mutation that occasionally occurs in the wild. Normally, plants without seeds would die without being able to reproduce; however, humans can and do selectively cultivate seedless plants by various techniques related to cloning.

As far as I know, there are two main reasons for preferring seedless plants:

• In fruits that are consumed by humans, seedlessness is aesthetically preferred.
• Because the plant is forced to reproduce asexually, the amount of variation in its descendants can be very tightly limited.

Hope this helps. --David Wahler (talk) 21:37, 25 October 2005 (UTC)

While the original bananas contained rather large seeds, seedless and triploid varieties have been selected for human consumption. These are propagated asexually from offshoots of the plant. The plant is allowed to produce 2 shoots at a time – a larger one for fruiting immeditely and a smaller 'sucker' or 'follower' that will produce fruit in 6 – 8 months time. The life of a banana plantation is 25 years or longer, during which time the individual stools or planting sites may move slightly from their original positions as lateral rhizome formation dictates. Latin Americans sometimes comment that the plants are "walking" over time. from Banana WAS 4.250 02:28, 26 October 2005 (UTC)

• I found this quote: The seeds for growing [seedless watermelons] are produced by crossing a normal diploid watermelon with one that has been changed genetically into the tetraploid state. The seeds from this cross produce plants that, when pollinated by normal plants, produce seedless melons. [68] There is more about advantages (including sweeter flesh and more vigorous growth), techniques, etc. Notinasnaid 08:56, 26 October 2005 (UTC)

Cavities are bad

Which is worse for your teeth: Coffee or Soda? --Lord Voldemort ^{(Dark Mark)} 19:33, 25 October 2005 (UTC)

This probably depends mainly on whether one takes sugar in their coffee. Without sugar it shouldn't lead to cavities, but it will stain teeth. In fact, coffee has been found to prevent some microorganisms, such as Streptococcus mutans, from adhering to teeth, which would help to prevent cavities. The chemical responsible appears to be trigonelline. [69]

Besides the sugar, sodas contain carbonic acid and often phosphoric acid, which may have an additional (small) effect on tooth enamel. ‣ᓛᖁᑐ 20:17, 25 October 2005 (UTC)

Except isn't coffee very acidic? It doesn't eat through enamel? I haven't done any pH tests in a long time, so I don't really remember. Thanks anyway, Eequor. --Lord Voldemort ^{(Dark Mark)} 21:01, 25 October 2005 (UTC)

This site suggests that the pH of a good cup of coffee should be approximately in the range of 4.9 to 5.2. This site indicates that the pH of carbonated cola beverages is around 2.5; cola is much nastier stuff. TenOfAllTrades(talk) 21:09, 25 October 2005 (UTC)

Soft drinks containing relatively high quantities of phosphoric acid (this includes most proprietary colas) are capable of dissolving the mineralisation of teeth. If you have (are) a pre-adolescent child with newly fallen deciduous teeth to spare, you can prove this by leaving one in a glass of cola. BEWARE: after a week or so, there will be nothing left for the tooth fairy to find. Physchim62 21:43, 25 October 2005 (UTC)

I suppose you mean soda pop, not sodium (aka soda). In Dutch 'soda' means the latter. I now wonder if that is also the original meaning in English and, if so, why the drink was named after it (or was it?). DirkvdM 09:05, 26 October 2005 (UTC)

Isn't the reference desk wonderful? I ask a question and within a short period of time I get all kinds of response. I guess it seems soda (a.k.a. soda pop) is worse. Now I just need to find some kid's teeth to knock out and try Physchim62's experiment. See ya everybody. --Lord Voldemort ^{(Dark Mark)} 13:43, 26 October 2005 (UTC)

What did cellophane replace?

Just curious, I haven't seen this on the article... --65.117.156.222 19:34, 25 October 2005 (UTC)

Greaseproof paper and tin foil. Still used, but for different purposes now. smurrayinchester^{(User), (Talk)} 19:59, 25 October 2005 (UTC)

Skeletal, smooth, and cardiac muscle evolution

Does anyone have any information on the evolutionary pathway of muscles? I was wondering also if this info can be applied to a possible muscle evolution article on wikipedia. 64.12.117.12 21:56, 25 October 2005 (UTC)

Sounds like it should be covered in an article with a broader scope. It's not though. -- Ec5618 23:04, 25 October 2005 (UTC)

Ok, but I still want to know the evolutionary pathway of muscles. Can anybody suggest any good links and or references? We can also integrate this information into the muscle page if the topic isn't broad enough to merit its own article. 64.12.117.12 00:13, 26 October 2005 (UTC)

"Phylogenetic Relationship of Muscle Tissues Deduced from Superimposition of Gene Trees", Satoshi OOta and Naruya Saitou, Mol. Biol. Evol. 16(6) 856-7, 1999 pdf or html: abstract: "Muscle tissues can be divided into six classes; smooth, fast skeletal, slow skeletal and cardiac muscle tissues for vertebrates, and striated and smooth muscle tissues for invertebrates. We reconstructed phylogenetic trees of six protein genes that are expressed in muscle tissues and, using a newly developed program, inferred the phylogeny of muscle tissues by superimposition of five of those gene trees. The proteins used are troponin C, myosin essential light chain, myosin regulatory light chain, myosin heavy chain, actin, and muscle regulatory factor (MRF) families. Our results suggest that the emergence of skeletal-cardiac muscle type tissues preceded the vertebrate/arthropod divergence (ca. 700 MYA), while vertebrate smooth muscle seemed to evolve independent of other muscles. In addition, skeletal muscle is not monophyletic, but cardiac and slow skeletal muscles make a cluster. Furthermore, arthropod striated muscle, urochordate smooth muscle, and vertebrate muscles except for smooth muscle share a common ancestor. On the other hand, arthropod nonmuscle and vertebrate smooth muscle and nonmuscle share a common ancestor"

I need 15 math facts for the number 95.

• Be specific – explain your question in detail if necessary, addressing exactly what you'd like answered. For information that changes from country to country (or from state to state), such as legal, fiscal or institutional matters, please specify the jurisdiction you're interested in.
• Include both a title and a question – the title (top box) should specify the topic of your question. The complete details should be in the bottom box. Questions not following this format may be deleted.
• Be courteous – questions are answered by humans, not computers. This is not a search engine. Don't write in ALL CAPITAL LETTERS.
• Do your own homework – if you need help with a specific part or concept of your homework, feel free to ask, but please do not post entire homework questions and expect us to give you the answers. -- Ec5618 23:34, 25 October 2005 (UTC)

Is that homework? -- SCZenz 22:47, 25 October 2005 (UTC)

1. 95 is a semiprime, being the product of two prime numbers, 5 and 19.
2. Its proper divisors add to 25; it is a deficient number.
3. It is the number of planar partitions of 10. [70]
4. It is the fifth hendecagonal number.
5. It is 1 less than 96
6. It is 2 less than 97, etc AllanHainey 11:24, 26 October 2005 (UTC)
7. Its 1011111 in binary ..
8. 10112 base 3
9. 1133 base 4
10. 340 base 5
11. 235 base 6
12. 164 base 7
13. 137 base 8
14. 115 base 9
15. And of course 5F in base 16 (hexadecimal) --Majts 18:53, 26 October 2005 (UTC)

Reverse Stockholm Syndrome

Posting here because this got no response in 'humanities' -

Is there a term for Stockholm Syndrome in reverse – ie, the captor developing a love for his victim ? Tintin 23:08, 25 October 2005 (UTC)

No --Majts 18:55, 26 October 2005 (UTC)

• Thanks Tintin 23:01, 26 October 2005 (UTC)

• • Somones been watching Waking the Dead ;) -Rob

The reason is that it is a normal thing for a person to begin to sympathize with those around them. The Stockholm Syndrome is only worth noting in that it seems quite bizzarre that a person who is kidnapped and threatened with death would sympathize with their kidnappers to such an extent that they will then kidnap and kill others to further their cause. StuRat 16:13, 29 October 2005 (UTC)

October 26

What are the airplane window manufacturers?

Who manufactures passengers' small windows for Boeing and Airbus? Are these windows interchangeable between different airplane models (other than advanced Boeing 787 windows)? -- Toytoy 00:45, 26 October 2005 (UTC)

I'd tell you, but then I'd have to kill you :) They are made by subcontractors to Boeing and Airbus, unfortunately, I don't know which ones. And while they look similar, no, they're not interchangeable (except between very closely related aircraft, like the Airbus A318/319/320/321 family, which are just different-length versions of the same plane). QuantumEleven | (talk)

How to breakup stamps for the maximum profit?

This hot babe may worth $577,500! You can use the money to buy a real airplane!

From Inverted Jenny:

"The inverted Jenny (or Jenny Invert) is a United States postage stamp of 1918 in which the airplane in the center of the design was accidentally printed upside-down. Only 100 of the inverts were ever found, making this error one of the most prized in all philately ..."

A block of four was auctioned May 19 in New York for $2,970,000 and set a world record.

The 100 inverts were from a sheet accidentally purchased by collector W. T. Robey. The collector "quickly resold the entire sheet to a dealer for $15,000. Within a few weeks, the stamps were separated, with most sold off individually for a few hundred dollars each. A few blocks of four were preserved." [71]

If you were the dealer, what would you do? What is your strategy to separate the stamps? A complete sheet is beautiful but how do you sell it? How much can you ask for it? With only one buyer, you can only milk him/her so much. What is the plan or strategy of separation? ... -- Toytoy 01:32, 26 October 2005 (UTC)

If I were the dealer, I'll do a quick survey of possible buyers, how many of them, how much would they pay, before I separate the stamps.

The buyers would also want to know how many stamps the dealer plans to keep. The last thing you want is to pay 10,000 dollars for one piece of stamp and find out the dealer still has 99 stamps somewhere in a safe. You can never resell your stamp for a reasonable profit because if you want to sell your stamp for $500, I can always separate another stamp and sell it at $450. Probably I cannot keep too many stamps. People know there must be at least 100 of them.

Maybe I can mail one stamp and use the cancelled stamp to create a false sense of rarity. "See, the first owner was too dumb to waste 95 stamps to send mail order catalogs. Many used stamps are now simply gone. I managed to buy his 5 remaining stamps."

Maybe I'll keep lots of stamps and sell my first batch to some fat and foolish buyers. ;) -- Toytoy 01:51, 26 October 2005 (UTC)

Any decent collector would be able to tell the difference between a modern cancellation and one from circa 1918. There's also a good chance it would get stolen if you tried to mail it. -Drdisque 01:58, 26 October 2005 (UTC)

I mean if I were the dealer of 1918. -- Toytoy 02:21, 26 October 2005 (UTC)

I seem to remember a short story where a dealer bought the only 4 remaining stamps in the whole world of an extremely rare set, and promptly burned 3 of them to massively increase the value of the final one. Can't remember the author, though. Proto t c 12:01, 26 October 2005 (UTC)

Personally, I don't think burning three stamps makes sense. The remaining stamp may gain some value, but very likely not that much. If these stamps belong to the "2nd tier", maybe increased rarity can boost its value. A stamp used to worth $10,000 may become $50,000 if you burn the three of them. Maybe not.

If these stamps are first class ones, you may lose a lot by burning three of them. You may find many collectors willing to pay $1,000,000 for your stamp, but none of them can afford to pay $5,000,000. So you sell the remaining stamp to someone at $1,200,000. There are too many rare stamps. People can always chase after other ones.

The moral of the story: Find a cash cow before you reach the lighter. If your cash cow is fat and dumb enough, burn the three stamps. Otherwise, let other collectors own them. -- Toytoy 14:51, 26 October 2005 (UTC)

heterolithic vs monolithic breccia

What is the difference between heterolithic breccia and monolithic breccia?

It depends on the mechanical processes which have broken up the original rocks. If the original rocks were clumped together by a landslide, say, then they may well have come from the same type of stone, such as limestone. Hence monolithic. But those rocks are then conjoined by a chemical process again, then they can form breccia. Same answer for heterolithic, except that the original rocks are of different types of stone. Ancheta Wis 09:20, 26 October 2005 (UTC)

The Mickey Mouse strategy

Copyrights last forever because when your Rotten Rodent copyrights are about to expire, you hire some crooked politians to extend these rights.

Now, imagine you're a fat rat farm owner who wants to buy some years from the Banana Congress. What would you ask for?

• If you ask for a 100 zillion year extension, it will take lots money to buy every naysayer. Even if you do it, you can only enjoy a few year's benefits. After that you retire and die. You don't want to give free meals to your heirs from your pockets.
• If you only ask for a miseralbe 3-week-cheap extension it will not be worthy of anyone's trouble.

What would you do? -- Toytoy 04:39, 26 October 2005 (UTC)

• See rhetorical question. Notinasnaid 08:35, 26 October 2005 (UTC)

Since you're interested in rodents, perhaps you might want to read our Rat choice article or this Krugman column on Rat Democracy. David 08:59, 26 October 2005 (UTC)

Practically, you ask for 20 years' extension to existing copyrights, and do so every 10-20 years. See Sonny Bono Copyright Term Extension Act and THE MOUSE THAT ATE THE PUBLIC DOMAIN for examples where this has already happened. (I happen to think you're correct about congress being purchased, b.t.w.) Ojw 21:48, 28 October 2005 (UTC)

Can big cats purr?

I'll assume you mean can for the first word. Anyway, the answer appears to be some. See our article on purring and the discussion at lion. — Lomn | Talk / RfC 16:05, 26 October 2005 (UTC)

Yet another light-in-a-box question

Reading the past couple of questions about this lead me wonder: If light can be reflected by the inside of a prism (total internal reflection), would it be possible to send light into a prism so that it could not escape. If so, what would happen as you kept sending light into it? smurrayinaHauntedHouse...Boo!^{(User), (Talk)} 17:33, 26 October 2005 (UTC)

Internal to the prism there is loss, and due to that loss, the light will eventually decay. If you put enough light in, I suppose the loss in the prism would eventually add, until the prism melts from the heat that is created from the lost light. There is no light explosion. A laser is effectivly a light box, light traveling along the medium in the middle is amplified by stimulated emission, and eventually the light escapes from one end. You will find that lasers have to be cooled, due to losses in exciting the medium that supports the stimulated emission, as well as transport losses. Dominick ^(ŤαĿĶ) 18:06, 26 October 2005 (UTC)

Your invention looks exactly like a multi-mode, step-index optical fiber to me. You need perfect total internal reflection and your material must absorb no light to "work". Scattering resulted from multiple sources, including impurities (e.g. water) and slightly imperfect geometry, can easily ruin your try. If you pump too much light into your prism, you end up having some sort of unexpected nonlinear optical reactions. -- Toytoy 01:28, 27 October 2005 (UTC)

Ha! If you know this, then how is it unexpected? DirkvdM 08:58, 27 October 2005 (UTC)

Oops! If a lightening hits me. I know I shall become a superhero. I just don't know what kind of superhero I'll become. -- Toytoy 11:36, 27 October 2005 (UTC)

Calibration of Diesel Engine / Powertrains

Hi Friends! I am in a situation where I need to know something on how the diesel engine is calibrated. Basically, I am awaiting an interview call and the company is expecting me to have atleast some knowledge on the calibration. I tried to look for it on the search engines but could not find any information. I need to know, what is involved in the calibration of the diesel engine and how is it done? What are the things usually involved in the calibration process? I would appreciate any kind of positive response.

Thanks, Sush.

You probably need a technical manual of some kind. It will likely depend on exactly what kind on engine. A shop manual for the kind of thing you are expecting to work on would likely help. Trollderella 03:31, 27 October 2005 (UTC)

This would be through adjusting the governor or the injector pump. With a modern engine, much of this would be done through a computer. read more how diesels work at Diesel engine. -Drdisque 05:13, 27 October 2005 (UTC)

antacids

when I put a MOM tablet(milk of magnesia) into a beaker of hydrochloric acid, it changes color. I don't understand why.

how would the tablet(MOM) respond to the actual stomach when the stomach continues to secrete acid?If you could please reply.. thanks.

Not knowing the chemical makeup of MOM offhand, I can't be specific, but the former is the result of a chemical reaction. The color likely corresponds to a salt formed by the reaction of an acid and a base. For the latter, stomach acid is neutralized (along with the MOM) until the lesser of the two reagents is exhausted. Since the stomach will produce acid long after the tablet will release MOM, the stomach will remain acidic, the stomach will remain acidic (though less so than prior to the tablet). — Lomn | Talk / RfC 21:02, 26 October 2005 (UTC)

The active ingredient of MOM is magnesium hydroxide. It reacts with hydrochloric acid to produce MgCl2 which is colorless. If you see a color change it might indicate that your brand of MOM tablet has a stabilizer or sweetener or additional ingredient in the tablet that is reacting with the HCl. Read the fine print on the package of tablets, or try a different brand of MOM. I am assuming you are not doing this with a universal indicator which is designed to change colors as the reaction occurs?alteripse 00:46, 27 October 2005 (UTC)

October 27

African Hedgehog quills

I have a project in which my topic is "How bacteria helps animals survive" im stuck on the hedgehog. I know they have bacteria in their quills but i was looking into more detail. What bacteria is it, and what infections does it cause, and well i needed a source too. I was hoping someone here could help me. thanks, S.M.

From hedgehog: "Hedgehogs are easily distinguished by their spines, which are hollow hairs made stiff with keratin. Their spines are not poisonous or barbed".

Perhaps you could use the Komodo dragon, which is thought by many people to be a poisonous or venomous reptile. The Komodo dragon does not produce any poisonous or venomous substance, though it has a large population of deadly bacteria living in his mouth.

Some types of snake are also known to have a poisonous bite, thanks to bacteria in the mouth. -- Ec5618 23:45, 26 October 2005 (UTC)

I don't know about hedgehogs, but another example might be the bioluminescence that some deep sea fish use. I'm just not sure if it's bacteria in this case. And a favourite of mine are the mitochondria, which must be one of the oldest forms of symbiosis. DirkvdM 09:20, 27 October 2005 (UTC)

Also some spiders have bacteria on their fangs... Alphax ^τεχ 11:39, 28 October 2005 (UTC)

If your stuck on Hedgehogs, and dont want to switch to Wildebeasts, then you might look at either their eyes, or their digestive tracts. What do they eat, how do they digest, and how is their eyes moisturized? Just remember you have 3 to 4 pounds of flora in your gut, that you almost cannot live without, and your eyes, have many many types of bacteria in them. Artoftransformation 03:30, 27 October 2005, (PST)

Thanks for the response, and well, i am using the komodo dragon, which have 15-50 different types of bacteria, and bioluminescence is bacteria, some. i looked into it myself. Thanks for the tips :D

Life expectancy of triathletes

Was there any study done to find the average life expectancy of triathletes? I know that average life expectancy is somewhere around 77 and 79 years. I have heard many stories of older triathletes being in better physical shape (in terms of endurance and cardiovascular health) than average 20 year olds.

I don't know, but I am 30, and got my ass kicked running with a 70 year old triathlete. I'm not in terrible shape. Trollderella 02:49, 27 October 2005 (UTC)

Being in a better shape doesn't mean one lives longer. I believe increased metabolism might even reduce ones life expectancy and that especially the increased activity of the heart causes more wear and tear, also reducing the life expectancy. And I once heard that the bigger heart of athletes isn't quite healthy either. A variation on 'live fast, die young', I suppose. DirkvdM 09:36, 27 October 2005 (UTC)

I think there are too many variables and it hasn't been studied carefully. But to answer your point about wear and tear on the heart from exercise, that is not correct. A person in better shape will have a lower resting heart rate (RHR) than they would have when they are out of shape, because exercise increases the ability of the heart to pump blood. Thus even adding in the extra heart beats during exercise, their heart will beat less over a week or month say. Now the increased metabolism could be right and reduce lifespan, but having a healthier heart may or may not offset that. - Taxman ^Talk 12:38, 27 October 2005 (UTC)

Assuming the amount of heartbeats per life is given and that during exercise one's heart beats twice as fast and the increased size of the heart would account for a reduced rate of 10% during rest (say 72 in stead of 80 bpm), then the break-even point would be at 10% of one's time spent exercising. With 1/3 of the time spent sleeping only (semi)professional would exceed that. The 10% is just a wild guess, though, and of course will also depend on how much time one spends exercising, so it's a bit interdependent. DirkvdM 15:37, 27 October 2005 (UTC)

I don't think it's true that in humans the number of heartbeats per life is fixed. In some animals it more or less is, but not in people. Trollderella 17:07, 27 October 2005 (UTC)

Specific heat capacity of styrofoam cups

OK just a quick question that someone might be able to answer... what is the specific heat capacity of your average styrofoam cup?
-- Миборовский ^U|T|C|E 00:14, 27 October 2005 (UTC)

• I don't know about cups in particular, but my databook gives a value of 1.3 J g^-1 K^-1 for the specific heat capacity of polystyrene. Of course, it depends on the density, but according to the book, practically all plastics are in the range 1.2-2.1 --Bob Mellish 00:36, 27 October 2005 (UTC)

• • And remember that specific heat is an intensive property; the numbers above are the heat capacity per gram, so you will also need to know the mass of the cup. ike9898 00:56, 27 October 2005 (UTC)

Since styrofoam is expanded polystyrene, will the air trapped inside significantly increase or decrease the specific heat capacity of styrofoam? Or can it be safely assumed to be approximately 1.3 J/gK?
-- Миборовский ^U|T|C|E 01:50, 27 October 2005 (UTC)

• Hmmm. My databook doesn't say if that's for expanded polystrene or bulk. The only reference I can find online is for the structural kind of styrofoam, and gives a value of 0.27 in the wonderful units of Btu/(lb °F). If I've got the conversion right, that's 1.12 J/(g K). So a bit less. --Bob Mellish 02:11, 27 October 2005 (UTC)

1.12J/gK sounds really low... compared to water. If it's so low how is it such a good insulator?
-- Миборовский ^U|T|C|E 05:49, 27 October 2005 (UTC)

Isn't that actually the reason for it? If it absorbs no (or little) heat it won't conduct heat either, right? DirkvdM 09:43, 27 October 2005 (UTC)

Try using the SHC of air, and assume that the amount of polysyrene involved is minimal. Ojw 21:42, 28 October 2005 (UTC)

Buy a real calorimeter next time--152.163.101.12 21:50, 28 October 2005 (UTC)

Of course, that's it. The air is really the insulator. The polystyrene is just there to keep it from moving and dissipating heat through convection. DirkvdM 10:21, 29 October 2005 (UTC)

POLYMERASE CAIN REACTION

FOR WHAT SPECIFIC PURPOSE IS PCR USED?

NAME THE MIXTURES PLACED IN A PCR VIAL AT THE BEGINNING OF THE PCR PROCEDURE?

WHAT IS THE OPTIMUM TEMPERATURE FOR THE ENZYME DNA POLYMERASE USED IN THE PCR PROCESS?

Optimum Temperature? no problem, 40................... now figure out what temperature scale I'm using (-; --152.163.101.12 21:55, 28 October 2005 (UTC)

We have an article on the polymerase chain reaction which answers these questions. Chuck 00:24, 27 October 2005 (UTC)

And please turn off your caps lock. DirkvdM 09:44, 27 October 2005 (UTC)

This looks like a great exam question, or homework. Why would you come here when even a small amount of research on the web would answer these questions? David D. (Talk) 22:05, 28 October 2005 (UTC)

Resizing windows (microsoft windows, that is)

Sometimes something will happen so that every time I launch Internet Explorer, the window will be some odd size. I want to know 1) what causes this to happen, and 2) how to change it, so that it will open maximized. ike9898 01:06, 27 October 2005 (UTC)

• That seems to be a common problem. Workarounds can be found via Google, similar to this:

1. Open a single Internet Explorer window to the smaller size.
2. Drag the corners of the window until it completely fills the screen. Do not use the maximize button to enlarge the window.
3. Hold down the Ctrl key, keep it depressed, and using the mouse click File and then Exit on the menu bar. Do not use the "X" in the upper right corner to close the window.
4. Internet Explorer should now open in a full window.
5. If it still opens to a smaller size repeat the above instructions, substituting the "Shift" key for the "Ctrl" key.

See if it works for you?--inks^T 01:54, 27 October 2005 (UTC)

• Also, try clearing out your cache as well. For some reason I remember this being related to this, though intuitively I don't know why that would be. --Fastfission 02:41, 27 October 2005 (UTC)

A method I used (which didn't always work) was to resize the explorer window (IE is just an instance of that), right-click one of the directories to open it in a new window (possibly repeat until it opens in the right size) and then close the last window last. After that they should open in that size and position. A more definite solution involved messing about in the registry (with regedit I believe). But I forgot how (I now use Linux). Be sure to make a backup of the installation, though, because working in the registry is dangerous. DirkvdM 09:52, 27 October 2005 (UTC)

Thanks! These tricks worked for me. Any idea what causes it to happen in the first place? ike9898 13:57, 27 October 2005 (UTC)

msWindows sucks? Probably not the answer you were waiting for, but you're unlikely to get an answer to that unless someone at microsoft would bother to help out here (and you can forget about that), because the workings of msWindows are quite obscure. And for a good reason – they don't want people to know, which is the opposite of Linux, which depnds on people (especially programmers) being able to understand the inner workings. And those people will be more likely to help out here because it's a hobby for them. DirkvdM 15:43, 27 October 2005 (UTC)

Windows

Sometimes when I start my computer, windows boots... No, actually, what I want to know is, is there an open source windows program to take ripped dvds (VIDEO_TS) etc, and turn them into something smaller? Thanks! Trollderella 02:46, 27 October 2005 (UTC)

There's a version of VirtualDub around that parses mpeg2, so it should be able to handle this. See here. I haven't tried using it with direct dvd rips, though. —Cryptic (talk) 03:45, 27 October 2005 (UTC)

Thank you! This will take individual files, and turn them into other things, but that will give me a bunch of other files, since my ripper has split the DVD into 2gb files. That's ok, since DVD players just string them all together, but what I want is a program that will take the whole DVD structure, and remaster it as a single, compressed, and playable file... Am I dreaming? Trollderella 03:50, 27 October 2005 (UTC)

There are various websites that list such programs and often provide tutorials for using them. You might want to check out doom9.org or afterdawn.com, for example. (Note: The legality of ripping DVDs varies between jurisdictions. Before downloading DVD ripping tools, please make sure local law allows their possession and use. Or, failing that, try not to get caught. ;-)) Ilmari Karonen 17:14, 27 October 2005 (UTC)

Thanks – I'm not distributing them, just trying to make my backup archive smaller. Trollderella 23:25, 27 October 2005 (UTC)

Medicine: Nursing

What are the Main Focal points when detemining Input/Output (I/O) data of a client?

You'll have to figure out what a "main focal point" is; it sounds like nursing jargon with which I'm not familiar (sorry), and infer from context whether "input" and "output" are referring to process or to fluid balance sheets, but assuming your question refers to fluid balance, when charting inputs and outputs, the following are some of the main considerations:

• Intake
  • oral intake of fluids
  • fluid content of solid food
  • intravenous fluid
• Output
  • urine volume (including that lost incontinently and thus not measured)
  • fluid lost via perspiration (usually estimated)
  • fluid lost in vomitus (both measured and lost)
  • fluid lost in diarrhea and feces/ostomy output
  • output from surgical drains
  • fluid aspirated via nasogastric tube suction
  • volume lost in dialysis
  • volume lost as water vapor in respiration (usually not charted)
  • loss of blood volume via hemorrhage (including into dressings)

In general, charted inputs and outputs are quite inaccurate and must be supplemented by daily weights when the information is actually needed. In a healthy adult, output is 62% urine, 19% via skin, 13% via lungs and 6% in feces. - Nunh-huh 03:19, 27 October 2005 (UTC)

Anabolic Steroids

How do anabolic steroids work? How do they effect the cells and muscles of the human body?

Anabolic steroids are a type of steroid hormone. They pass through the outer membranes of many types of cells, interact with a cytoplasmic receptor for androgens and perhaps other receptors as well. The bound steroid-receptor complex moves into the nucleus of the cell, where it binds on certain target areas of the chromosomes, where it alters transcription of certain DNA sequences called genes. Activation of certain genes and inactivation of others results in a variety of changes of cell metabolism. Many of these changes involve increased rates of synthesis of various structural proteins such as those in cartilage and bone, certain functional proteins such as those in muscle, and certain protein hormones such as growth hormones. The net result is a stimulation of processes we call anabolic and a slowing of many processes we call catabolic. The anabolic processes tend to induce growth and enlargement of sensitive tissues and organs, or increases in density or strength. Does that answer your question? alteripse 04:12, 27 October 2005 (UTC)

See also: Androgen receptor. --JWSchmidt 17:47, 27 October 2005 (UTC)

peanut oil

what does the expiry date in peanut oil refer to – it getting rancid? if i wanted to use this expired oil as a massage oil is it safe? pls. enlighten. corina202.128.35.13 04:56, 27 October 2005 (UTC)

The expiry date on peanut oil only refers to the last date it can be sold. It has only a slight relation to its rancidity. Its supposed to be usable for a while after the expiry date, but the rancidity depends on the storage. If its kept refriderated, like all oils, it will react with oxygen at a slower rate, and be usable for long after the expire date. If it is kept in direct sunlight, it will oxidate much faster, and will most probibly be rancid before the expire date.]

NOTE: Food oils become rancid much earlier than you smell them. Artoftransformation 03:48, 27 October 2005 (PST)

It's probably safe to use rancid peanut oil externally, but, please, if you value the person you are massaging as a friend or client, don't. Trollderella 17:09, 27 October 2005 (UTC)

increase count in RBC

sir,

i would like to know about the chemical responsible for increase in RBC count after taking hygrophila spinosa preparation ,a medicinal plant which is semi aquatic.i would like to know whether the main component has been seperated yet or not.

thanking you

The only research paper indexed in pub med is PMID 11491586. This rat study from India found evidence of ability to raise the RBC count, but did not identify the specific substance responsible. I would infer from the wording of the abstract that as of 2001 the substance had not been identified. It also seems likely from the absence of follow-up papers since 2001 that the "haematinic effect" has not been reproducible in people, but I might be wrong of course and some major drug company may be in the secretive phase of investigating a potentially profitable protein. alteripse 11:46, 27 October 2005 (UTC)

A curious birth trait: veiled babies

I have searched wikipedia and I have also used search engines to try to answer this question. I am very curious to know any information (and images) that can be given about veiled babies. From what little I've been told, there are some babies who are born with a thin layer of skin covering their faces (called a veil). These babies are also supposed to be gifted psychics. My questions are: Where can information on this birth trait be found? What is the correct medical term for this condition? How often are babies born with this condition? --209.165.134.49 05:25, 27 October 2005 (UTC)

Your first stop: see caul. -- Toytoy 11:32, 27 October 2005 (UTC)

You are referring to a bit of folklore, called being "born with a caul." A caul would be a bit of the amniotic membrane that is ruptured during labor. An infant born with a largely intact piece of the amnion is referred to in the obstetric literature as being born en caul. See for example PMID 16035444 and PMID 12052593. Here is a picture. alteripse 11:45, 27 October 2005 (UTC)

Transparent GIFs / PNGs

I want to make the background of an image transparent. Can I make transparent images using any combonation of the following programs?

• MS Paint
• Microsoft Word
• Microsoft Powerpoint
• Microsoft Picture Manager
• Corel Draw

I am able to load such images into these programs, can I do it with these programs or do I have to shell out my $80 - $600 USD for fancy programs like Adobe Photoshop and/or Illistrator? — Kjammer ⌂ 05:47, 27 October 2005 (UTC)

Corel PhotoPAINT should be able to do this (included with the CorelDRAW suite). Otherwise the the GIMP. --R.Koot 06:18, 27 October 2005 (UTC)

Silly me, I forgot about the GIMP, It is on my Knoppix disc. Thank you for your help (it would've taken me weeks to figure this out.) — Kjammer ⌂ 07:53, 27 October 2005 (UTC)

Definition of mean curvature

Dear Sirs,

Your web-site mentions 2 definition of mean curvature for e.g. a 2-surface embedded in 3-space i.e.

H = (k_1 + k_2)/2 the average of the principal curvatures k_1 and k_2

but also, to within a constant:

H = div (n) where n = grad f/|grad f| for a hypersurface defined by f(x_1,x_2...x_n) = 0

My question

---

How do you establish the equivalence between these two formula?

[ Hint: start with the def of gradient ]Artoftransformation

A reference would be appreciated!

Thanks in advance

best wishes

Tony Scott RWTH-Aachen Germany

It looks like that the first formula is a emperical formula, ( for calculating and evaulaiting functions of (x,y,z..) or (r,θ,) and the second formula it its equivalent in Vector form. The relationship of these, of corse would be to calculate the Normal Vector of the curvature of the surface. It would hold that you can calcuate them for any hypersurface, provided that they are partialy diffrentiable in the direction of the gradient. ( note carefully, that the vector quanty grad f/|grad f| Either is positive or negitive ( that is the curvature is either convex or concave )and not infinte or undefined. Another access would be to start with the definition of the gradent in emperical form. ( The proof of the existance would be an advanced calculus subject. )

Refrence's would be both MathWord def: Mean Curvature and for a 2D curve in 3 space, would be the 3rd section of any college calculus text such as: Anton or a petecular favrote: Larson and Holister. Note that, MathWorld has EXCELLENT refrences at the end of their articles.

A simple test of all this undeciperal gibberish would be to work with the top and bottom of unit sphere, the top half would have a constant mean postive curvature over its surface(convex), and the bottom would have a constant mean negative curvature over its surface (concave), and extend it to unit hyperspheres in higher order spaces.

Artoftransformation

Space required by a bit of infomation

How much space does it take on a PC to store one bit of information? -EnSamulili 08:45, 27 October 2005 (UTC)

The answer depends on the form of knowledge representation you want. Ancheta Wis 09:59, 27 October 2005 (UTC)

Assuming that you are asking about a minimal representation, then an old text editor program like edlin consumes 12.3 KBytes. The typical block size for a current PC is 1/2 to 1 KByte. Thus the minimal size for a file will be 1/2 KByte. So the overhead consumed to store that one bit of information would be 12.8 KBytes. In the old days of computing this was a real consideration. Today 1 bit on a 1GByte PC would cost less than a billionth of the cost of that PC and can be neglected for all practical purposes, when a 100GByte external drive is a commodity item these days.

After two consecutive edit conflicts (hell, you guys are fast): Depends on on which medium it's stored. Assuming you mean surface area, on a chip these days you get about 1 GB on 1 cm² (very rough estimate), so that's (10^-4 m²) / (8 x 2³⁰ bits) or roughly (10^-4 m²) / (10¹⁰ bits) = 10^-14 m². For size in space multiply this by the thickness of the chip (or just the etched layer?). To this the encasing and connections might have to be added, depending on what exactly you want to know. A similar calculation might be done with a hard disk or optical disk or tape or whatever. But I'm going to eat now (irritating how these daily things can get in the way of having fun here). Of course, one may wonder if a bit exists if it can't be accessed (does something exist if I can't see it?), so you might have to add the hardware needed for that too (including some sort of monitor). DirkvdM 10:17, 27 October 2005 (UTC)

Thank you. I'm sorry I wasn't clear enough to say that physical space (3D) was the space I am interested in. Your calculation was exactly what I wanted to know, but could you help me with telling what the thickness of a typical chip or an etched layer is. -EnSamulili 12:42, 27 October 2005 (UTC)

Well, a chip or integrated circuit is roughly 2 mm thick (just look at one inside a computer), but that also includes the encasing. The Semiconductor fabrication article says the wafers on which the chips are produced are 0.75 mm thick. What is used in the first steps is photolithography, which uses nanolithography, so I'd say the etchings would be in the order of nanometers thick. So if you multiply by 'a few times' 10^-9 and round that up for safety you'd get 10^-22 m³. Remember this is all based on a lot of assumptions and guesswork, so take it for what it's worth. If I'd add 'give or take a factor 100' I shouldn't be too far off target. Does Wikipedia have something like an 'accuracy disclaimer'? :) DirkvdM 15:20, 27 October 2005 (UTC)

With accuracy like that, you're almost guaranteed work as an astrophysicist... Shimgray | talk | 13:12, 28 October 2005 (UTC)

I hope this is not meant to insult astrophysicists. :) DirkvdM 10:24, 29 October 2005 (UTC)

Why is the night sky always lighter during a thunderstorm?

Even if there's no lightning. It always seems tinged slightly pinkish and very light, as though it were only just after the sunset.

The phenomenon is called skyglow ☢ Ҡieff⌇↯ 13:34, 27 October 2005 (UTC)

The skyglow link talks mainly about the effect of electric lighting in cities.

Yes, but that's the cause of the glow. In remote areas, where there are no artificial lights, the sky doesn't glow at all when it's cloudy\stormy, it's just all completely dark except for the lightnings. ☢ Ҡieff⌇↯ 16:58, 27 October 2005 (UTC)

That's usually the source of apparently brighter skies on cloudy nights; clouds reflect city light back down far more efficiently than the open sky. (Of course even the very inefficient scattering of city lights by normally-low levels of atmospheric dust and water vapour is sufficient to obliterate faint astronomical sights.)

On a cloudy or stormy night far from artificial lights, it gets really dark in my experience—one no longer even enjoys the benefit of starlight by which to see. TenOfAllTrades(talk) 15:13, 27 October 2005 (UTC)

A. muscaria

In the Amanita muscaria entry a death from an american species of A. muscaria is referenced. I am unable to find this in the medical literature and am hoping the original author (or someone else) may have a source.

Thanks158.111.4.26

A canadian website lists active ingredient LD50 = 3mg/kg (a dose that kills 50% of people) at about 10 mushrooms. You can get to a lethal dose with less, much less. Eating half the LD50, doesn't mean you are safe, like any poison, only none is safe, you can still get sick go into a coma or have fatal convulsions. This amount of active poison will vary wildly with the mushroom growth and season. Only use the fly-agaric to kill flies. It is not a good choice for recreation.

It is a simple error to mistake other species for this species. [72] Do not try eating these mushrooms, if you screw up you are screwed. Many wives tales and drug folklore are untrue, and you do not want to stake your life on them. Let me repeat. Only use the fly-agaric to kill flies. Please wash your hands after handling them. Dominick ^(ŤαĿĶ) 19:20, 27 October 2005 (UTC)

Thanks--Was not planning on eating it--just trying to track down the source in the medical literature (case report in XYZ journal, for instance) to back up the statement that a human death was attibuted to it. The literature is full of case reports of bad side effects but I can't find a veridied report of death. Anyone else have any ideas?71.56.39.101

What event lead to the discovery of "lactate"?

I'm taking an IV therapy course and this question was posed to us. I've researched the web and found that Syndey Ringers invented Ringers Lactate but nothing about the event which led to the discovery. Please help. Thank you.

There are several websites that say Carl Wilhelm Scheele found Lactic acid in sour milk. I'm not sure this really means that he discovered lactate. He may have been the first to associate this particular chemical with its name and a particular source/process. --JWSchmidt 17:23, 27 October 2005 (UTC)

weights

My friends and I are having a discussion about liquid weight. Does 16 fluid ounces equal 1 pound?

• A fluid ounce is a measure of volume while a pound is a measure of weight. Whether one equals the other depends on the density of the liquid in question. - Mgm|^(talk) 15:43, 27 October 2005 (UTC)

• Only if the liquid has the correct density (of 1 lb per 16 fl. oz, whatever that comes to in SI units). Since liquids have differing densities, however, the relationship between a fluid ounce and a mass ounce is nothing more than an unfortunate choice of terminology. — Lomn | Talk / RfC 15:43, 27 October 2005 (UTC)

• It's not however completely coincidence, because a fluid ounce was chosen to be approximately the volume of water that weighs an ounce (depending of course on temperature and other things). DJ Clayworth 17:23, 27 October 2005 (UTC)

Copyright infringement

Okay I know this is a homework question but I really need help on this. I will fail my class if I don't do this and it's due on Halloween! Okay here it is.

Your subject is copyright infringement. Now find one person or groups of people whom have been caught doing copyright infringement. Find at least 3 examples. Note the following:

• What specifically they were caught doing.
• How were they caught doing it?
• Did they receive large fines? If so, how much were they?
• Did they receive a jail sentence? If so, what was the sentence and how long was it?

If you could help me that would be great. Thanks!--63.199.33.66 16:49, 27 October 2005 (UTC)

You might start by looking at Wikipedia:Copyright problems. Or Software piracy. If you think about ways in which people might violate copyright laws it shouldn't be hard to come up with ideas for people who have broken them. DJ Clayworth 17:20, 27 October 2005 (UTC)

Figure out is copyright infringement is a criminal offense in your jurisdiction (this varies). If you cannot do this, you deserve to fail. Physchim62 18:14, 27 October 2005 (UTC)

It sounds like your class is using one of those lesson plans provided by the music industry, teaching children not to copy music (e.g. homework = finding people who went to jail for running Kazaa). What's the class actually like? Ojw 21:15, 27 October 2005 (UTC)

What we do is this: We sit around while the teacher gets definitions ready, and play's on his laptop. He takes cell phone calls and leaves us sitting there before we can log onto our computers and do work. We do endless projects we've done 7 projects since the start of the year, and get about 3-5 hours total (Sometimes less) and we do typing for 1 hour every week. Half of our grade is usally on how we name the file, and put it in his grading folder. We have a VERY bad technology teacher, and class. This should answer your question Ojw--63.199.33.66 16:28, 28 October 2005 (UTC)

"Figure out is copyright infringement is a criminal offense in your jurisdiction (this varies). If you cannot do this, you deserve to fail." What do you exactly mean by this? "Figure Out is Copyright" Are you trying to say "Figure Out what Copyright is" makes since. 63.199.33.66 17:14, 31 October 2005 (UTC)

I got one extra week but still I would like help--63.199.33.66 17:20, 31 October 2005 (UTC)

Your best bet would be to run a search on Slashdot. Copyright complainers tend to gather there.--Fangz 21:43, 31 October 2005 (UTC)

Birthday probability question

This came up at my conscientious objector place. We know that if there is a group of over 365 people, at least two people will have the same birthday. But if we pose the question "backwards", i.e. how large a group of people has to be so that every day of the year is a birthday of someone? The correct answer, of course, is "infinite", as there is nothing preventing, for example, everyone from being born on the same day.

But given the number of people, what is the probability of every day in the year being someone's birthday? For 1 to 364 people, it is 0, i.e. such a thing is impossible. For exactly 365 people, it is 1/(365!), i.e. 1 divided by the factorial of 365. But what is the probability for larger groups? (For simplicity, we ignore leap years.) — JIP | Talk 16:38, 27 October 2005 (UTC)

This section is getting pretty long, so I've moved it to Wikipedia:Reference desk/Science/Birthday probability question. The short answer seems to be

$P(m,n)=\sum _{k=0}^{n}(-1)^{k}{n \choose k}\left({\frac {n-k}{n}}\right)^{m}$

where m is the number of people and n the number of possible birthdays (= 365). —Ilmari Karonen 01:22, 28 October 2005 (UTC)

Unix command question

I know the head and tail commands give me the N first or last lines of a text file. But how can I get all the lines except the N first or last ones? — JIP | Talk 17:44, 27 October 2005 (UTC)

man head and man tail should help you. Specifically, you want head -n -N and tail -n +N+1, where N is the number of lines to skip. Ilmari Karonen 19:08, 27 October 2005 (UTC)

Internet Explorer breaking

Hello. So my gimpy old computer is messing up every time I try and start Internet Explorer.

A "Microsoft Visual C++ Runtime Library" message pops up, telling me in a pleasingly jolly manner that there's a "Runtime Error!" and "R6016 – not enough space for thread data".

What the heck does this mean, and how the heck do I stop it. Once I OK this, and then the 'Internet Explorer is shutting down' message (even though it hadn't yet started up), IE then starts up fine without me clicking anything else.

It's IE version 6, and, um, I'm still on Windows 98. *shame*. Programs I see running when I press ctrl-alt-del are Internet Explorer, Explorer, Msnmsgr (despite me trying to close it, it won't let me, cause a hotmail window is open in IE), Atdialler1 (yes, I'm connecting on a modem, too), msnappau, Loadqm, Systray, E_s10ic2 (think this is my printer app) and Rnaapp.

Please, clever Wikipedians, help a brother out. Proto t c 17:57, 27 October 2005 (UTC)

File:Firefox logo 305x150.png

Get Firefox --Quasipalm 21:02, 27 October 2005 (UTC)

I already have Firefox. This is not what I asked. I asked for help fixing IE. *expletives deleted* Proto t c 22:32, 27 October 2005 (UTC)

Might be a virtual memory problem... how much space do you have left on your hard drive? Try deleting unnecessary files and uninstalling unused applications. Check your virtual memory settings as well. --Canley 00:14, 28 October 2005 (UTC)

This isn't what you want to hear, but try installing Linux! Seriously though – what version of ie are you using? Have you tried reinstalling it? I think you can download it. Trollderella 23:24, 27 October 2005 (UTC)

• Given the message you're getting, trying Canley's suggestion may be worth a go. - 131.211.210.11 07:17, 28 October 2005 (UTC)

Excuse me for flogging a dead horse, but given the amount of problems people seem to have with IE (and msWindows in general) I wonder why people insist on keeping on using it. DirkvdM 07:32, 28 October 2005 (UTC)

I'll try and figure out my virtual memory. Trollderella – version 6.0.something. I will reinstall it. Dirk – most people go on using Windows because it's user friendly. Yes, it has security and bug issues, but it's a heck of a lot easier for the layman to use than Linux or whatever. Ditto IE. Linux doesn't have as many problems because a) a lot less people use it, and b) The people that do use it are technically adept. If the same number of users (and with that, the same level (or lack of) technical knowledge) had Firefox and Linux as do those with IE and Windows, then I dare say there'd be just as many problems with those two programs. Everyone else, thank you for your help. Proto t c 12:15, 28 October 2005 (UTC)

Linux is not the only Operating System beside msWindows. Mac's are actually quite known for their user-friendliness. But I was mainly referring to browsers. Of course many more people use IE than other browsers, which is why there will be more postings about it, but why not install a bunch of them (most are for free) and switch if one gives you problems? Easy as pie. Or do you have a specific reason to use IE? The only one I can think of is when you are a webdesigner and have to test your 'designs' on all (mqin) browsers (which is done waaaaay too little, by the way)? DirkvdM 09:53, 29 October 2005 (UTC)

Watching a DVD image file?

Is it possible to watch a dvd image file without actually burning it to a disc? For what it's worth, it is a nero image file. Thanks!!

Yes it is, and not just DVDs, but any disc image. All you need is to create and mount a virtual drive using a special program. I suggest Daemon Tools ☢ Ҡieff⌇↯ 20:51, 27 October 2005 (UTC)

endangered animals

What endangered bird flies 2 miles south in Winter?207.200.116.202

Why would we do your homework for you? --Quasipalm 21:00, 27 October 2005 (UTC)

Graying hair

Why doesn't hair gray uniformly. That is, why do sideburns tend to gray before the hair on the top of the head, instead of uniformly (randomly) all over the head. Are those hair follicles different? --Quasipalm 21:07, 27 October 2005 (UTC)

You are correct: there are differences between hair follicles and surrounding skin cells and growth signals in different parts of the body. Why doesn't hair grow uniformly on all areas of the body? Why isn't hair on all parts of the body equally sensitive to androgens? The answer to the first question (about growth) is likely to involve many different factors, while the answer to the second (about androgen sensitivity) is likely to invole only a couple, but both are examples of bodywide differences in hair growth. My hunch is that graying is more like the limited number of factors influencing androgen sensitivity but we don't know what they are as well. alteripse 10:07, 28 October 2005 (UTC)

Battery power

Why do batteries seem to regain a portion of their power after not being used for a period of time. Shouldn't the power be at the same level as it was when last used? --Quasipalm 21:09, 27 October 2005 (UTC)

Batteries produce power through an electrochemical reaction. In general, such reactions can involve multiple processes, not all of which necessarily run at the same speed. As the battery runs down, the slowest of these processes become the limiting factor for the power output. When you unplug the battery, these slower processes continue to run as the battery gradually returns to chemical equilibrium. Thus, when you plug it in again, the overall reaction can run faster (and thus produce more power) for a while, until the slowest processes become a bottleneck again.

As an analogy, think of a bottle of shampoo (or ketchup or any other viscous liquid). When the bottle first runs out, there's still quite a bit of shampoo stuck to the sides of the bottle. If you leave the bottle standing upside down for a while, however, the shampoo slowly flows down the walls, enabling you to squeeze a little more of it out of the bottle. Ilmari Karonen 23:29, 27 October 2005 (UTC)

What if?

What would happen if someone added a template to the end of their signature?--Lapsed Canadian 21:44, 27 October 2005 (UTC)

• It seems I can answer my own question--Lapsed Canadian 21:51, 27 October 2005 (UTC)

Well, it puts extra load on the servers for one thing. Take a look at Wikipedia:Transclusion costs and benefits--Commander Keane 01:09, 28 October 2005 (UTC)

Long story short, if you must do it, use {{subst:templatename}} instead of just {{templatename}} -- it'll put less burden on the server. Or, you could be a Wikipedia hero and just not use them at all… Garrett Albright 04:18, 28 October 2005 (UTC)

October 28

Lipofuscin,dementia and age spots

What is the chemical formula of lipofuscin and is it the same chemical involved in dementia and age spots.

If known what causes its production?

Richard

The article on lipofuscin has some of the answers that you seek. Dismas|^(talk) 00:47, 28 October 2005 (UTC)

Lipofuscin can accumulate in many cell types but I do not think it is specifically associated with age spots; they seem to be due to uneven distribution of melanin. Some neurodegenerative disorders have been associated with lipofuscin accumulation. Lipofuscin is not a single chemical; here is a more detailed article about a major retinal lipofuscin associated with macular degeneration: Biosynthesis of a major lipofuscin fluorophore in mice and humans with ABCR-mediated retinal and macular degeneration. There have been attempts to find associations between Alzheimer's disease and lipofuscin, but I don't think links have been demonstrated. --JWSchmidt 04:53, 28 October 2005 (UTC)

white blood cells

Has there been any scientific studies that prove a positive reaction to building white blood cells in an aging male? For example: taking a certain vitamin?

Thank you,

Sandra Crosson

—Preceding unsigned comment added by 71.244.229.60 (talk • contribs)

Can you rephrase more clearly?

I don't understand what you mean by building: increasing the number of white cells or making them different in some way?

I don't understand what you mean by positive reaction: a detectable effect of building white blood cells or a detectable beneficial effect of building white blood cells?

Are you asking if taking a certain vitamin increases WBC count?

Are you asking if it is beneficial to increase the number of WBCs?

You are aware that too few WBCs are bad and too many WBCs are bad? That making more if you have too many is not necessarily beneficial? That there is no demonstrable advantage to having a WBC count of 9,000 per mm3 instead of 8,000 in a healthy person? alteripse 03:20, 28 October 2005 (UTC)

Restorative Dentistry

What does "recement" mean? It is in benefits lists for dental insurance, and used in the context of "recement crown", "recement inlay" or "recement cast".

--64.174.7.191 03:16, 28 October 2005 (UTC)

At a wild guess, try reading as "re-cement", or "apply cement to [a crown, inlay or cast] a second time". Notinasnaid 07:18, 28 October 2005 (UTC)

The word "recement" means exactly what it literally says. Dental restorations--that is to say, devices used to re-construct the shape and form of a damaged tooth (i.e., fillings, inlays, crowns, or veneers) often (but not always) need to be cemented to a tooth in order for them to be reliably retained in place. However, they don't always stay in place forever. The combined action of salivary dissolution and repetitive chewing force can cause disintegration of the luting cement over time, leading to loosening and displacement of the restoration. If there is no significant damage to the tooth by decay and the restoration still fits, it can be recemented in its proper position.

Whether a dental insurance policy pays a benefit for a recementation procedure depends on the provisions of the policy. However, most dental insurance carriers would much rather pay for a low-cost procedure such as a recementation than pay for an expensive replacement of an otherwise serviceable dental restoration. In the U.S., the insurance industry and the American Dental Association have collaborated on a set of procedure codes, and there are codes for recementation, giving the technique official recognition. --
Mark Bornfeld DDS
dentaltwins.com
Brooklyn, NY 18:49, 28 October 2005 (UTC)

GPS Protocols

No-where on the internet can I find any reference of an NMEA protocol to Garmin protocol converter. Does such a thing exist ? What I am actually seeking to do is to use my GPS receiver (NMEA protocol) to find my location on Google Earth (which only uses Garmin / Magellan inputs). Any joy anyone please ? Thanks so much--jrleighton 03:42, 28 October 2005 (UTC)

(moved from Wikipedia Talk:Reference desk by Garrett Albright 04:09, 28 October 2005 (UTC)

Interesting question. This document about the NMEA standard describes the NMEA protocol (for the benefit of the nautically challenged, NMEA is a standard interface for transferring navigational information between electronic devices on boats). It looks like it's implemented on stop of some very standard serial communications protocols, so it should be very straightforward to build a gadget that speaks and understands NMEA. As to speaking the Garmin/Magellan protocol, I don't know if the protocol is public. It probably wouldn't be difficult to reverse engineer, however. However, given that GPS units are incredibly cheap these days, by the time you've purchased all the components to build a converter it may have been cheaper just to buy an appropriate GPS; which is probably why you can't buy a Magellan protocol to NMEA protocol converter!--Robert Merkel 06:18, 28 October 2005 (UTC)

science / history

Why do different science disciplines not cross reference each other? Hence we seem to end up with only 20,000 years of human history but the globe being populated by man crossing land bridges that existed millions of years ago and no-one in the science community questions this.

• I'm not sure what the problem is with that. It is frequently accepted that man has been around a lot longer than modern history has records (which means history goes back around 5200 years), and that none of the early histories came down to us. What was happening before that is interesting, and studied as prehistory. What should the science community be questioning? Notinasnaid 08:02, 28 October 2005 (UTC)

Landbridges did not only exist "millions of years ago." The Bering land bridge, which connected Siberia and Alaska, was in existence 22,000 – 7,000 years ago, well within the "20,000 years of human history" that you have cited. I agree with Nitinasnaid: I don't think I understand your point. If it is that different scientific disciplines don't overlap and cross-reference one another, I think you are mistaken. Neuroscience and biochemistry are two good examples. So is geology, which borrows from physics, biology, and chemistry, among other disciplines. If your point is that the wisdom found in history and science are mutually exclusive, I have to disagree. -Parallel or Together? 08:12, 28 October 2005 (UTC)

I accept weather changes geography in much shorter time scales than geology, but everything I have read indicates Africa is the cradle of humanity but Australia has the oldest tracable records of mankind and links to Australia severed through continental drift, not climate change.

Modern Homo sapiens came to Australia between 40,000 and 60,000 years ago by land bridges and perhaps small-distance sea crossing (see Prehistory of Australia). On the other hand, Homo sapiens appeared in Africa around 200,000 years ago (see Human evolution). Humans may have migrated from Africa to Australia in that span of 140,000 years (this is the single-origin hypothesis). Or Homo sapiens may have independently evolved in different areas of the world from the local Homo erectus populations, who themselves had migrated out of Africa many thousands of years before (this is the multiregional hypothesis). Does this help or did I misunderstand you again? (if so, I apologize). -Parallel or Together? 09:13, 28 October 2005 (UTC)

Helpfull – Thank you.

You left out the alien contact hypothesis made famous by von Däniken. Aliens carried man all over the globe! If it wasn't for those meddling aliens, we would have gotten away with it too... Dominick ^(ŤαĿĶ)

Haha, you are right. This was a significant oversight on my part. Please forgive me. -Parallel or Together? 14:10, 28 October 2005 (UTC)

One thing that should be clarified is that the sub-species homo sapiens sapiens refers to modern humans, while the species homo sapiens also includes ancient humans, such as Homo sapiens idaltu. StuRat 17:01, 28 October 2005 (UTC)

White blood cell

How does the body get rid of WBC??? What i mean is that RBC are destroyed in the spleen and liver, so where are the WBC destroyed??? And also why do RBC do not have nucleus, by having one it can increase its lifespan, why not???

Thank you for you time...:)

The average life-span of neutrophils is about 11-16 days, most of which is spent maturing in the bone marrow. About 24 hours after they are released into the circulatory system, they undergo apoptosis and are phagocytized by other cells. As for RBCs, you probably know that some animals normally have circulating nucleated RBCS, but that most mammals, including humans, don't. Mammals have smaller end-vessels in their circulatory systems: small enough that RBCs must be able to be deformed (squeezed) to pass through them – easier if they are smaller and enucleate. In addition, an RBC with no nucleus can contain a higher hemoglobin concentration and therefore carry more oxygen. - Nunh-huh 16:53, 28 October 2005 (UTC)

Factorial

Could someone please explain how to calculate decimal factorials (ex. 7.35! or 3.9!)? I found the explanation at Factorial a bit confusing. Don Diego^(Talk) 16:16, 28 October 2005 (UTC)

• In general, you have to calculate the Gamma function for the argument plus one. This isn't particularly easy, so you're better off looking up the result in a table. --Bob Mellish 16:31, 28 October 2005 (UTC)

• Basically, to get n! you have to evaluate $\int _{0}^{\infty }x^{n}e^{-x}dx$. I doubt there's an easier way, except for certain specific values. —Keenan Pepper 17:11, 28 October 2005 (UTC)
  • Note that that's actually how you calculate (n-1)!. Incidently, Window's Calc.exe will cheerfully handle non-integer factorials. --Bob Mellish 19:03, 28 October 2005 (UTC)

No, that's n!. The gamma function is shifted by one, but the integral I gave is not.

—Keenan Pepper 19:29, 28 October 2005 (UTC)

• Ah yes, I see now. Sorry. --Bob Mellish 23:21, 28 October 2005 (UTC)

• • There are easier ways than evaluating the the integral directly. I have written a 15-line implementation of Lanczos approximation for the Gamma function in Python which is currently available at the Swedish Wikipedia. The Gamma function is implemented by pretty much any decent mathematics software, and there is also an online arbitrary-precision calculator at http://oldmill.uchicago.edu/~wilder/Code/hpgamma/. Not much hope calculating it by hand, though. Fredrik | talk 19:28, 28 October 2005 (UTC)

Ooooh – this caught my attention. I didn't know that there was such a thing as a "Lanczos approximation" outside of quantum mechanics! Another score +1 for the RD :-) --HappyCamper 03:54, 29 October 2005 (UTC)

Direction of data on CDs

Does the data on a CD start at the outside and go inward, like a vinyl record, or vice versa? Clockwise or counter-clockwise? What about DVDs? Are there any media that go the "wrong" way? —Keenan Pepper 17:15, 28 October 2005 (UTC)

It goes inside and out, as you can verify by looking at a blank CD-R and one that's partially full. As for the direction, that would be clockwise (assuming you're looking at the data side of the disc), as that's the direction a CD spins in a CD player. --Pidgeot (t) (c) (e) 18:40, 28 October 2005 (UTC)

There is also plenty more information on compact disc that's worth looking at :) ☢ Ҡieff⌇↯ 20:00, 28 October 2005 (UTC)

I've heard that Gamecube discs have the data track spiraling the opposite direction; I'm not sure if they record it from the outside in, or if the disc actually rotates in the opposite direction. --David Wahler (talk) 20:01, 28 October 2005 (UTC)

You wouldn't have to spin it backwards to record, you could just reverse the order of the bits when recording it. It would be interesting to find out if they do this though, it would certainly make piracy harder. --Quasipalm 21:20, 28 October 2005 (UTC)

A GameCube disc isn't all that different from a regular disc, they just use a proprietary filesystem and disc structure that a regular DVD drive can't read. It doesn't spin "the wrong way" around. (If it did, I'd imagine it would have been a nightmare to make the Panasonic Q work.) --Pidgeot (t) (c) (e) 21:48, 28 October 2005 (UTC)

You may be thinking of the X box, which by default reads data from the outside, inward. Nothing stops it from being compatible with standard CDs and DVDs, but the native Xbox read mode is backward from normal media.

birds

how many species of birds are there? - anon

Second paragraph of Bird. ;) —Keenan Pepper 19:32, 28 October 2005 (UTC)

Lymph Nodes

can someone please tell me how many Lymph Nodes are under you left arm.

Thanks Sue M.

Sue, there is no specific number of lymph nodes in the left armpit (these would be called left axillary nodes, by the way). The number differs from person to person, from very few (less than five) to more than thirty. One study (in women with breast cancer) showed an average of about 10 lymph nodes per axilla. - Nunh-huh 21:36, 28 October 2005 (UTC)

Potential Energy/ Kinetic Energy/ Conservation of Energy / Linear Momentum

What is the exact mathamatical relationship between momentum, initial momentum, final and change in energy? conservation of energy? thank you--152.163.101.12 21:08, 28 October 2005 (UTC)

• $p=mv$ (momentum is mass times velocity)
• $I=mv-mu$ (Impulse is change in momentum)
• $I=Ft$ (Impulse is force times time)
• $E=0.5mv^{2}$ (Energe is half mass times velocity squared)

• Conservation of energy is just "Energy cannot be created or destroyed", it can only be converted into other forms of energy. For example, an object falling loses gravitational potential energy and gains kinetic energy. Heat, sound, gravitational potential, elastic potential... the list goes on. But it's all conserved. Deskana 22:09, 28 October 2005 (UTC)

However, note that Einstein taught that energy alone is not always conserved, nor mass alone, but both are conserved in accordance with $E=mc^{2}$. Mass is regularly changed to energy, in the Sun, in nuclear reactors, in nuclear weapons, and in radioactive minerals. Energy can also theoretically be changed into mass, although we haven't found a way to do so yet. Of course, in normal (non-nuclear) reactions, the conservation of energy is perfectly valid. StuRat 00:54, 29 October 2005 (UTC)

Actually, energy gets converted to mass all the time—for instance, a pair of photons producing a particle-antiparticle pair. And if I recall correctly, even in ordinary energy transfers, a tiny amount of the energy causes the mass to increase by a tiny amount (even in heat transfers or chemical recations)...but I could be wrong about that. In any case, I think that for the purposes of the principle at least, mass can be regarded as a special form of energy, and conservation of energy still holds. Note that it may not hold on short time scales in quantum mechanics. — Knowledge Seeker দ 04:30, 29 October 2005 (UTC)

It actually does hold, always, provided you define "energy" in the right way. ;) More specifically, even on short time scales in quantum mechanics, physicists assume conservation of energy and allow virtual particles to have the "wrong" mass; this is often explained instead as an energy-time uncertainty principle, but that's probably less accurate. -- SCZenz 22:10, 29 October 2005 (UTC)

October 29

Porous Steel?

When Steel is boiled in water does it have pores which open up to absorb? Such as when traps are boiled in Walnut hulls or logwood dye and they take on a darker color. The question is does steel have pores?

The only increase in "pore" size you wuold have would be the expansion of the steel and thus the increase of intermolecular distances. So no, steel doesn't have pores. --Borbrav 00:30, 29 October 2005 (UTC)

Darkening of steel after boiling with plant extract would be a result of either staining or oxidation. alteripse 00:42, 29 October 2005 (UTC)

Always something new: Porous Steel. --JWSchmidt 23:20, 29 October 2005 (UTC)

Silverwing

If you've ever read the Silverwing series of books you know that there are two species referenced called the Silverwing and Brightwing bats. A lot of the other species seem to be based on real ones, so does anyone know what Silverwings and Brightwings could possibly be in real life? Thanks for the help! ♥♥purplefeltangel♥♥ 00:48, 29 October 2005 (UTC)

By the way, Silverwings are said to have short, broad silver wings and short tails, while Brightwings have long, narrow wings, bright fur, and "elegant" ears. ♥♥purplefeltangel♥♥ 06:53, 29 October 2005 (UTC)

It sounds like it could be a species of moth, perhaps even tropical moths. Does this help? --HappyCamper 11:52, 29 October 2005 (UTC)

Uh, they're bats. :D I'm asking what bat species they are. ♥♥purplefeltangel♥♥ 21:34, 29 October 2005 (UTC)

Quote from author here [www.kennethoppel.ca]:

"All my characters are based on real species of bats -- even Goth and Throbb! Shade's a silver-haired bat; Marina's a red bat, Goth is something called a spear-nosed bat, also known as the Vampyrum Spectrum. Cama Zotz is based on a real Mayan bat deity of the same name. I also wanted to pick names that seemed appropriate for flying creatures. So I used the names of some angels (Cassiel, Ariel), the names of special winds (Zephyr, Chinook, Scirocco -- you can look them up!) and mythic heroes (Icarus). As for Shade, his name just reminded me of shadows and twilight. Marina means "of the sea" -- she lives on an island as the story begins. And Goth is kind of shorthand for the word "gothic" -- which conjured up all sorts of images of vampires and dungeons"

There you go. Prodego ^talk 21:52, 29 October 2005 (UTC)

Do rats really eat feces?

More specifically, is dog poop really a significant food source for rats? Even more specifically, if I keep my collected dog poop (individually wrapped in do-do-bags) in an open container in my bushes in Florida and then I see a rat, is the poop likely to be a significant cause of the presence of the rat? Note that some city governments list dog feces cleanup as a critical rat-prevention tactic. They also indicate that rats "spread disease" but I think this fact is also disputed.

Rats are suspected of aiding in the spread of the bubonic plague during the Black Death pandemic... although this fact is indeed somewhat disputed. However, rats are technically cabaple of spreading disease, it is just not proven beyond a shadow of a doubt that they did so in this particular instance. And yes, rats eat their own feces[73] so they might also eat dog feces. -Parallel or Together? 12:35, 29 October 2005 (UTC)

I would say that if you find the bags have been chewed up with the feces strewn about the container, suspect the rats. If the bags remain undisturbed, I would probably not worry about it attracting the rats. Dismas|^(talk) 04:41, 30 October 2005 (UTC)

Actually, as I understand it, what is not certain is that the black death was bubonic plague, but the plague is spread by rats. Or, rather, strictly speaking, it's the fleas that live on the rats that infect humans (which is why it's a bad idea to kill rats when there's an outbreak – the fleas will switch to humans). But, more on the subject, coprophagy is a way for rodents to get all the nutritional value out of their food. In the case of rabbits, they have two different kinds of droppings; the ones you get to see are the second kind because the first is eaten. Apparently, dogs also do this, but not (necessarily) for the same reason. So I wonder if dog poo has the qualities (nutritional value) that a rat would be looking for. Then again, the rats might just be plain stupid and not realise that they're doing something useless. Shit happens, so to say. DirkvdM 06:36, 30 October 2005 (UTC)

What is the most intelligent insect?

Or has nobody really bothered to find out? Kid Apathy 13:20, 29 October 2005 (UTC)

While nobody knows for sure (as they keep dropping their number 2 pencils when taking standard IQ tests), I would hazard a guess and say bees. Social animals have an inherent need for greater intelligence to communicate with others in their group. In the case of bees, they are known to communicate the location of food via a "dance" performed in the hive. However, insect intelligence is thought to be almost entirely instinct, with very little capacity for true learning. This explains how such apparent intelligence can be packed into such a small brain. Instinctive behaviours require far less brain mass than learning. StuRat 13:26, 29 October 2005 (UTC)

Take a look at Mushroom bodies. If you want more, try this: Evolution, Discovery, and Interpretations of Arthropod Mushroom Bodies --JWSchmidt 23:11, 29 October 2005 (UTC)

Depends on how you define intelligence, of course, and that's a tricky one. Any definition will be anthropomorphic. By such a definition you'd be hard put to find any intelligence in insects at all. As StuRat says, insect 'intelligence' is basically instinct. Human intelligence is an ability to adapt to changing circumstances (learning). But this sort of intelligence is not what makes insects tick (no pun intended). There are different ways to be successful as a species. Intelligence is one of them, and it happens to be the one that homo sapiens has specialised in. Other methods are evolution and numbers. Insects as they are may produce so much offspring that some of them will find the right habitat to survive. On top of that, variation will lead to evolution. But humans don't have quite as much offspring and live much longer (making evolution work slower). So they use intelligence (which can be seen as a form of evolution in one individual).

Sturat also mentions bees, but my bet is on ants. Here, however, the intelligence is not in the individuals, but in the 'hive' (what's that called with ants?). Individually, ants are pretty stupid (even working against each other), but as a group they can move mountains (well, create mounds, anyway). DirkvdM 07:05, 30 October 2005 (UTC)

Bees, ants, yes, but Jiminy Cricket is no fool either. David Sneek 09:19, 30 October 2005 (UTC)

• I think we'd have to define intelligence first, and whether or not we recognize collective or emergent intelligence (which is how the social insects would win) or whether or not we are considering individual intelligence. Ants and bees on the individual level are doing nothing more than following a fairly preset series of commands — it's just that those commands, spread among a few thousand individuals, can create some pretty neat results. I'm not sure how you'd measure individual intelligence in insects (problem solving?) and I'm not sure anyone has tried to. --Fastfission 15:26, 30 October 2005 (UTC)

One could say that humans are also a collection of (by themselves) stupid cells that only display intelligence when they cooperate. Our cells are just stuck together, whereas ants have the freedom to move around by themselves. But they also have to stick to the collective to survive. Which is sort of a communist (or fascist) society. Which is why communism and fascism will never work; the constituent parts are just too individualistic. Fyi :) . DirkvdM 08:08, 31 October 2005 (UTC)

I would say ants are likely to be the most 'intelligent', though that is fairly broad as there are hundreds of species. As some species have developed agriculture (of fungi & captured aphids), slavery & warfare. These are pretty strong indicators of intelligence in humans, though not – for the last 2 – of social conscience or morality.AllanHainey 15:25, 31 October 2005 (UTC)

Related question: Has an insect exhibited tool use? --Fangz 20:57, 31 October 2005 (UTC)

The Portia spider appears to be quite cunning. Some of its behavious are practically mamalian. It's quite creepy if you've ever seen them in action. Vonspringer 04:26, 1 November 2005 (UTC)

A division question

I'm having trouble dividing $3x^{4}+5x^{3}-2x^{2}+6x+3$ by $x+2$. Could someone please show me how so that I can solve the problem and then apply the method I've learned to other, similar problems? Thanks, anon.

That's called synthetic division. See that article for details. StuRat 17:18, 29 October 2005 (UTC)

On second thought, a better introduction to the material is located at Polynomial long division. StuRat 17:23, 29 October 2005 (UTC)

The 'do your own homework' thing has made students smarter, I see. :) DirkvdM 07:08, 30 October 2005 (UTC)

Telnet option 200?

Half curiosity, half pragma (implementing my own telnet option parser for a new MUD codebase), but what does telnet option 200 (C8 in hex) signify for MUDs and MUD clients? Google draws a blank, and it's an 'unofficial' option as far as RFCs and their ilk are concerned. So does anyone know what this does, or shall it be consigned to the pit of obscurity?

The only reference I could find to it is [74], where you can also see another mysterious telnet option: 170. I also found about options 85 (Mud Compression Protocol, v1), 86 (Mud Compression Protocol, v2), 90 (Mud Sound Protocol), and 91 (Mud Extension Protocol). Which client or server is sending you option 200? --cesarb 00:12, 30 October 2005 (UTC)

I'm seeing it come up on IRE muds, when Rapture is sending the initial option communication, along with 86 (COMPRESS2) and asking if EOR is OK (can't recall the number off hand. Probably nothing, because MUSHclient just says no to number 200, but it's a curiosity. --Sam Pointon 10:53, 30 October 2005 (UTC)

WWII German Enigma Machine

The WWII German Enigma machine is based on what mathematical models? In other words, what is the primary mathematical basis of the Enigma? Do you know of any websites that provide a discussion of its mathematical basis?--158.80.0.2 19:12, 29 October 2005 (UTC)

• How's about The Cryptographic Mathematics of Enigma from the NSA? --jpgordon∇∆∇∆ 20:09, 29 October 2005 (UTC)

biology

why are plants green?

1. Chlorophyll, the chemical they use to absorb energy from sunlight, is green. -- SCZenz 22:07, 29 October 2005 (UTC)

Another way to explain that is that chlorophyll absorbs and transduces light of the reddish wavelengths most efficiently, and it reflects most light of green wavelengths. alteripse 22:17, 29 October 2005 (UTC)

Plants are all "green with envy" that animals get to move around and they don't. StuRat 16:47, 30 October 2005 (UTC)

Transverse meridional/"great-ellipse" arcradius?

Consider the loxodromic equations:

   $VLeg$ = The "vertical" (Δlatitude) "leg";
   $HLeg$ = The "horizontal" (adjusted Δlongitude) "leg";

    $Azg$ = Graticular (spherical) azimuth;

   $HyP_{g}$ = Loxodromic hypotenuse;

$VLeg=\cos \!\left\{Azg\right\}\times HyP_{g}=|\Delta Latitude|;$

$HLeg=\sin \!\left\{Azg\right\}\times HyP_{g}={\frac {VLeg\times |\Delta Longitude|}{\operatorname {arccosh} \!\left\{\sec \left\{Lat_{2}\right\}\right\}-\operatorname {arccosh} \!\left\{\sec \left\{Lat_{1}\right\}\right\}}};$

For the spherical loxodrome:

$Azg=\arctan \!\left\{{\frac {HLeg}{VLeg}}\right\};$

$HyP_{g}={\sqrt {VLeg^{2}+HLeg^{2}}};$

For the ellipsoidal loxodrome (referring here to an oblate ellipsoid [$a>b$]):

    $a,b$ = equatorial, polar radii;

$\operatorname {M} \!\left\{Lat\right\}=\!\left\lbrack {\frac {a}{b^{2}}}\right\rbrack ^{2}\operatorname {N} \!\left\{Lat\right\}^{3}\quad {\mbox{(Meridional arcradius/radius of curvature)}};$

$=k_{1}\,\!$?

$\operatorname {N} \!\left\{Lat\right\}=\!{\frac {a^{2}}{\sqrt {(a\times \cos \!\left\{Lat\right\})^{2}+(b\times \sin \!\left\{Lat\right\})^{2}}}}\quad {\mbox{(Normal/transverse equatorial arcradius)}};$

$=k_{2}\,\!$?

$a\times \operatorname {HyP} _{e}\!\left\{Lat\right\}$	$={\sqrt {(VLeg\times \operatorname {M} \!\left\{Lat\right\})^{2}+(HLeg\times \operatorname {N} \!\left\{Lat\right\})^{2}}},$
	$={\sqrt {(\cos \!\left\{Azg\right\}\times HyP_{g}\times \operatorname {M} \!\left\{Lat\right\})^{2}+(\sin \!\left\{Azg\right\}\times HyP_{g}\times \operatorname {N} \!\left\{Lat\right\})^{2}}},$
	$={\sqrt {(\cos \!\left\{Azg\right\}\times \operatorname {M} \!\left\{Lat\right\})^{2}+(\sin \!\left\{Azg\right\}\times \operatorname {N} \!\left\{Lat\right\})^{2}}}\times HyP_{g},$
	$=\operatorname {O} \!\left\{Azg:Lat\right\}\times HyP_{g};$

The ellipsoidal loxodromic azimuth has its own relationship set:

$\sin \!\left\{Azg\right\}\times \operatorname {N} \!\left\{Lat\right\}$	$={\sqrt {\operatorname {O} \!\left\{Azg:Lat\right\}^{2}-(\cos \!\left\{Azg\right\}\times \operatorname {M} \!\left\{Lat\right\})^{2}}},$
	$=\operatorname {O} \!\left\{Azg:Lat\right\}\times {\sqrt {1-(\cos \!\left\{Azg\right\}\times {\frac {\operatorname {M} \!\left\{Lat\right\}}{\operatorname {O} \!\left\{Azg:Lat\right\}}})^{2}}},$
	$=\operatorname {O} \!\left\{Azg:Lat\right\}\times \sin \!\left\{Aze\!\left\{Lat\right\}\right\};$

Likewise,

$\cos \!\left\{Azg\right\}\times \operatorname {M} \!\left\{Lat\right\}=\operatorname {O} \!\left\{Azg:Lat\right\}\times \cos \!\left\{Aze\!\left\{Lat\right\}\right\};$

Hence,

$\sin \!\left\{Aze\!\left\{Lat\right\}\right\}=\sin \!\left\{Azg\right\}\times {\frac {\operatorname {N} \!\left\{Lat\right\}}{\operatorname {O} \!\left\{Azg:Lat\right\}}};$

$\cos \!\left\{Aze\!\left\{Lat\right\}\right\}=\cos \!\left\{Azg\right\}\times {\frac {\operatorname {M} \!\left\{Lat\right\}}{\operatorname {O} \!\left\{Azg:Lat\right\}}};$

$\tan \!\left\{Aze\!\left\{Lat\right\}\right\}=\tan \!\left\{Azg\right\}\times {\frac {\operatorname {N} \!\left\{Lat\right\}}{\operatorname {M} \!\left\{Lat\right\}}}={\frac {HLeg\times \operatorname {N} \!\left\{Lat\right\}}{VLeg\times \operatorname {M} \!\left\{Lat\right\}}};$

The point of all this, is that it calls into question the validity of the classically prescribed arcradius at a given latitude, in a given direction:

$\operatorname {O} \!\left\{Azg:Lat\right\}$	$={\sqrt {(\cos \!\left\{Azg\right\}\times \operatorname {M} \!\left\{Lat\right\})^{2}+(\sin \!\left\{Azg\right\}\times \operatorname {N} \!\left\{Lat\right\})^{2}}},$
	$={\frac {\operatorname {O} \!\left\{Azg:Lat\right\}}{\sqrt {\cos \!\left\{Azg\right\}^{2}+\sin \!\left\{Azg\right\}^{2}}}},$
	$={\frac {1}{\sqrt {\left[{\frac {\cos \!\left\{Azg\right\}\times \operatorname {M} \!\left\{Lat\right\}}{\operatorname {M} \!\left\{Lat\right\}\times \operatorname {O} \!\left\{Azg:Lat\right\}}}\right]^{2}+\left[{\frac {\sin \!\left\{Azg\right\}\times \operatorname {N} \!\left\{Lat\right\}}{\operatorname {N} \!\left\{Lat\right\}\times \operatorname {O} \!\left\{Azg:Lat\right\}}}\right]^{2}}}},$
	$={\frac {1}{\sqrt {\left[{\frac {\cos \!\left\{Aze\!\left\{Lat\right\}\right\}}{\operatorname {M} \!\left\{Lat\right\}}}\right]^{2}+\left[{\frac {\sin \!\left\{Aze\!\left\{Lat\right\}\right\}}{\operatorname {N} \!\left\{Lat\right\}}}\right]^{2}}}},$
	$=\operatorname {O_{e}} \!\left\{Aze\!\left\{Lat\right\}:Lat\right\};$

At a given point, an azimuth is an azimuth: Whether it is loxodromic or orthodromic only identifies the "behavior" of the line it represents--an azimuth of 73.263° means, at a given point, a direction of 73.263° from due north, PERIOD (end of discussion). Right?

Now consider the prescribed, accepted equation of the arcradius:

   $Azg$ = Graticular (spherical), orthodromic azimuth at Lat;

   $Aze$ = Elliptical, orthodromic azimuth at Lat;

$\operatorname {P} \!\left\{Aze:Lat\right\}={\frac {1}{{\frac {\cos \!\left\{Aze\right\}^{2}}{\operatorname {M} \!\left\{Lat\right\}}}+{\frac {\sin \!\left\{Aze\right\}^{2}}{\operatorname {N} \!\left\{Lat\right\}}}}};$

If one calculates a minuscule (ellipsoidal geodetic/orthodromic) distance and divides it by the spherical angular distance ("ADg", found via the "spherical cosines for sides" equation), it will nearly equal O_e{$Aze:Lat$}, not P{$Aze:Lat$}!
Consider this example (where $a=6378.136$, $b=6356.75$):

 $Lat_{1}=33.682045083^{\circ };$

 $Lat_{2}=33.682045085^{\circ };$

   $\Delta Long=\ \ 0.000000003^{\circ };$

$ADg=\ \ 0.00000000986412851^{\circ },$

 $=\ \ 0.00000000017216152034{\mbox{ rad}}\,\!;$

 $Azg=78.30189780458^{\circ };$

 $Aze=78.35474883236^{\circ };$

$Distance=\ \ 0.00000109899218359{\mbox{ km}}\,\!;$

${\frac {Distance}{ADg}}=\mathbf {6383.49487983} {\mbox{ km}};$

Now compare:

$\operatorname {O_{e}} \!\left\{Aze:Lat\right\}=\mathbf {6383.49487983} {\mbox{ km}}=\operatorname {O} \!\left\{Azg:Lat\right\};$

 $\operatorname {P} \!\left\{Aze:Lat\right\}=\mathbf {6383.49} {\mathit {759558}}{\mbox{ km}};$

This should demonstrate that O_e{$Aze:Lat$} is the arcradius at ($Aze,Lat$), not P{$Aze:Lat$}, shouldn't it? If O_e{Aze:Lat} is not THE arcradius, then what type of arcradius is it? And if P{$Aze:Lat$} is THE arcradius, then how does it relate to a minuscule distance?

I can't believe this concept is unknown—maybe archaic/obscure and/or just forgotten (or, more likely, known/recognized by another name—?).
Given that "original research" is a Wikipedia no-no, I would like to know if this concept/equation is recogized—or, if indeed this is OR, worthy of a paper at PlanetMath or some such site! P=) ~Kaimbridge~ 23:46, 29 October 2005 (UTC)

Don't take this the wrong way, but: what exactly have you been huffing? Kid Apathy 23:43, 29 October 2005 (UTC)

To put it more politely, the supporting math is fine, but please start with an English description of what you are trying to prove, in layman's terms. StuRat 16:44, 30 October 2005 (UTC)

(comment and reply moved from my talk page—shouldn't the the discussion stay here?) ~Kaimbridge~ 20:36, 30 October 2005 (UTC)

Hmm...very interesting question...What is the context of the original problem? --HappyCamper 01:49, 30 October 2005 (UTC)

Well, the "arcradius" itself is the problem! P=)
I know about geodetic formulation and its "conformal" nature, requiring an "auxiliary sphere" (I have copies of Sodano's and Vincenty's classic papers--as well as others--but I prefer Saito's straight-forward Gaussian Quadrature, all of which are given in Richatd Rapp's Geometric Geodesy, Part II <Ohio State Univ.>). Since great-circle distance equals the (arc)radius times the angular distance, it follows that the (arc)radius equals the distance divided by the angular distance. So, on an ellipsoid, the smallest possible geodetic distance divided by its corresponding graticular/spherical angular distance equals the arcradius at that latitude, in the direction of the geodetic line. Try it on a meridian (which is a "simple" ellipse): Calculate a minuscule distance and divide it by ΔLat (which, in this case, equals the graticular angular distance)—it will nearly equal M{Lat}/O{0:Lat}.
Now, before you get ahead of the discussion and think "hey, wait a minute, I know what he is up to...he thinks he found a geodetic formula using just Lat/Long, not requiring an auxiliary sphere and all its complications...but he doesn't realize...". But, yes, I do realize this wouldn't find the traditionally defined, conformal geodetic distance, but it does find the graticular geodetic distance—what I call the "parageodetic" distance—which is the elliptical distance on a spherical globe: That is, calculate the angular distance between the two points on the spherical globe, then, staying constrained to the graticule (which, by its origin, is always spherical, thus "graticular"/spherical), find the average elliptical arcradius along that great-circle segment and multiply the two together (in the same way you would multiply the average value of M{Lat} <between $Lat_{1}$ and $Lat_{2}$> by ΔLat to find the distance along a meridian <between $Lat_{1}$ and $Lat_{2}$>). Think of the antipodal case: The geodetic distance will always be north-south, along a meridian, as that is "conformally" the shortest distance (i.e., if you theoretically pulled a string from a point on the equator, along the equator, to the other side, the string would "lift" until it is north-south, when it reaches its antipodal point), whereas the parageodetic distance would be the elliptical distance along any great circle (also known as a "transverse meridian") between and including a common, vertical meridian and the common, horizontal equator. There is a popular geodetic approximation ("Andoyer's Approximation") that is actually a parageodetic approximation!
But I realize that the "parageodetic"—as far as I know—would be considered waaaaay out into original research land, so I'm not attempting to go anywheres near there! P=)
The idea of O{Azg:Lat}/"omniversal"/"transverse neridional" arcradius (at least in some form), however, I don't think is OR (especially if it is presented right). I suspect that it may just be a mostly forgotten concept, given all of the advances in geodetic formulation for finding the "shortest" (i.e., conformal) geodesic. Either that, or P{Aze:Lat} is supposed be the "omniversal"/"transverse neridional" arcradius in some other reference form (e.g, "reduced", "parametric", etc.), with some way to convert it to the more apparent O_e{Aze:Lat}—thus the question to the RD.
As for all of the loxodromic intro, that is meant to be an attempt at presenting O{Azg:Lat}'s derivation. ~Kaimbridge~ 15:46, 30 October 2005 (UTC)

chemical structure of rubber (natural and synthetic)

I have been loking around for the chemical structure of Natural Rubber and Synthetic Rubber but seem to be having no luck. Any webistes or books that anyone knows of and has some information of the chemical structure of rubber would be of great use to me.

Thank you

• Our synthetic rubber article has some info. - Mgm|^(talk) 11:12, 30 October 2005 (UTC)

Latitude CPx Probelms, BSOD and more

This is what happens.

1. Laptop boots up fine, Connects to internet via 56k/LAN modem 2. Laptop runs for a while, then all the sudden, it flickers to a BSOD(Blue screen of death. The blue screen that has Windows error messages.) Then the comptuer instantly shuts down, like a force down, then starts rebooting, and go to the screen, where it checks for fragmentation (Something close to that) If I leave the Laptop off for a while, then i can turn it back on, and it will work fine, then goes back to step 2.

Then soemone told me to clean out the heat sink, and fins of the fan. I did, and i put the whole computer back togeather, and plug it in. I turn it on, and the Lights blink (CAPS Num, Scrool lock)they blink a couple times then it turns off. Nothing on the screen, nada. Did i just screw up my hard drive or something? Any Ideas on what's wrong?

I used to have a similar BSoD problem on my laptop where it would show the BSoD for about half a second and then force-down/reboot. This was nowhere near enough time to capture the error messages displayed. I thought of using a camcorder to record the screen, but the BSoDs were too sporadic for me to catch it. However, Windows did record the technical details to hard disk, and Windows told me it was a problem with a device driver. Further investigation led me to discover that this was my audio driver. My audio driver tends to have problems in other places, too.

So my guess is that there might be a link between your modem driver and the BSoD. And about your second (more serious) problem, well, it's a bit late to tell you this unfortunately, but in general you shouldn't take apart laptops. Even the professionals can make critical mistakes doing it. Everything is very compact and fragile, and it can be almost impossible to put back together a laptop successfully after taking it apart. Desktops are much, much easier because everything is neatly placed and substantially spaced out to fiddle with. It doesn't look like your laptop is even getting to BIOS; the Num, Caps and Scroll Lock lights flash as a basic circuit thing, but it doesn't seem to be progressing. Try pressing/holding F12 while turning it on, this usually activates the BIOS menu on most systems while it's going through. It's worth a try, however, I doubt it would work, and I'm sorry to tell you the news but the future for your laptop doesn't look good. -- Daverocks 13:04, 30 October 2005 (UTC)

Well it may be too late for my poor laptop, but this was a Goverment laptop, and i put XP on it, so how come 1-2 months after i start using, it, it starts having these problems? 69.181.206.232 17:48, 30 October 2005 (UTC)

Seems to be fixed. Had soem error with RAM think it overheated. But either way seems to be fixed.Lordned 19:32, 30 October 2005 (UTC)

October 30

LCD monitor problems

Hello, all. Before I purchased my new laptop, my old laptop was giving me quite a lot of problems. What happened is that sometimes, the LCD display would show some sort of "snow", but differently. If you had, for example, three white pixels aligned horizontally, a magenta pixel would appear next to the third pixel. Also, if there was a black pixel below and left of another pixel, that pixel would appear lime green (my guess is hexadecimal #00FF00). I don't use it anymore, but I've always wondered what was causing the problem. All the connections were properly plugged (I checked them myself several times), and I've heard somewhere that it could have been because of a property of LCDs, but I didn't get more explanations. Is that possible? If it is, what was causing it? Titoxd^(?!?) 03:47, 30 October 2005 (UTC)

Maybe a stuck pixel? Take a look, but it doesn't seem to explain why the pixel is faulty. -- Daverocks 12:09, 30 October 2005 (UTC)

Also, most LCD monitors warn of occasional random pixels, due to limits of the technology. That said, it sounds like your case may go beyond the normal range. StuRat 16:37, 30 October 2005 (UTC)

No, neither one seems to fit this problem. If you switched a window, producing a different combination of pixels, some of the magenta pixels would appear normal, and some of the normal would appear green or viceversa. It probably is one of those cases not covered by the six sigmas. Titoxd^(?!?) 01:06, 31 October 2005 (UTC)

Bridge type identification

I tried this on Talk:Bridge but didn't get a response. Can someone tell me – what sort of bridge is the Tasman Bridge? Concrete arch? More pics here. -- Chuq 04:42, 30 October 2005 (UTC)

I'm not sure about the construction technique, but by the look of it, I think it is a Box girder bridge. smurrayinaHauntedHouse...Boo!^{(User), (Talk)} 09:06, 30 October 2005 (UTC)

Prestressed concrete, including the columns. Not an arch. Do you need more info? --Commander Keane 14:55, 30 October 2005 (UTC)

Let's see...It is a beam bridge (as opsoded to an arch). It's not a box girder, it's I beams, specifically 14 precast, prestessed concrete ones (24 in. wide at the top of each).--Commander Keane 16:21, 30 October 2005 (UTC)

Coloured glass

Inspired by the biology question above, why is it that when I look at a tainted window on the outside it has the same colour as when I look at it from indoors? If the colour on the outside is a reflection of that wavelength, then on the inside I'd have to see white light without that wavelength, so the complementary colour. On second thoughts, I'd have to do this test with the lights out on the inside. Would that be the cause of it, that I see the reflection of the lights inside? But they're much weaker than sunlight, so that sounds unlikely. DirkvdM 07:21, 30 October 2005 (UTC)

Practically, you don't "see" the color of the glass, you see the color of the objects behind the glass. If I wear dark brown glasses, everything I see is tinted in dark brown color. I see dark brown dogs and dark brown cats.

Let's say the sunlight has R-G-B components (highly simplified) and your glass absorbs all green light:

• Case 1: You're inside:

sunlight (RGB) → light hits an outside object (scattering; RGB) → glass → filtered light (RB) → your eyes (RB)

• Case 2: You're looking from the outside to the inside (above):

sunlight (RGB) → glass → filtered light (RB) → light hits an inside object (scattering; RB) → glass (filtered again; RB) → your eyes (RB)

The complementary colour (G) is absorbed. You don't see it. You may see the direct reflct of the sun, but the color of the light reflected from the outer surface of the glass is not necessarily the color of the glass (affected by multiple factors). -- Toytoy 08:42, 30 October 2005 (UTC)

Ah, so it's a matter of absorption in stead of reflection. Makes sense. But where does the energy go? Is it turned into heat (sounds unlikely)? Or, another option I now think of, is the frequency changed? DirkvdM 08:14, 31 October 2005 (UTC)

Under the normal condition, most of the absorbed light energy turns into heat. If you place a blackened steel plate under the tropical sun at noon for a period of time, you can cook an egg on it. The heat in steel transfers to the egg very quickly. If you place a black plastic board under the sun, it will not cook the egg. Moreover, the object can always transfer the heat elsewhere. So the temperature will not rise indefinitely.

However, if you're in a typical living room, the artificial lighting is too weak to heat anything. (Fluorescent lamps: Too little infrared. Incandescent bulbs: Can only heatup nearby things.) If you're in a movie studio, these kilowatt lights can easily burn something if you fail to take reasonable care.

Frequency change is very unlikely if you're not talking about nonlinear optics. -- Toytoy 12:58, 31 October 2005 (UTC)

Or blackbody radiation? Omegatron (talk) 19:54, 3 November 2005 (UTC)

It should be noted that there are varieties of glass that reflect different colours differently. I have no idea what goes into them, but a local glassware company called Iittala makes various glass objects in a color they call "rose-olive", which looks greenish in reflected light but purple when seen against the light. A reasonably good image can be found at [75] (front left), but the effect is much more striking when seen in reality. In many photos on the web, such as [76], the glass simply looks lime green due to excessive reflected studio lighting. —Ilmari Karonen 16:00, 31 October 2005 (UTC)

• These probably work by selectively reflecting (rather than absorbing) certain colours. If you look at light reflected off the glass, it look one colour, say green. If you look at light through the glass, it looks like the complimentary colour (magenta). Dichroic filters work the same way. You generally make this sort of effect by putting some kind of optical coating on the glass. --Bob Mellish 16:31, 31 October 2005 (UTC)

Statistic on death worldwide, due to Malaria, from an admissible source (WHO preferred)

I am looking for a single figure on deaths worldwide due to Malaria (I believe the figure is about 1 million) from an admissible source, such as the WHO. I've looked on their site, but cannot find a stated figure for 2004 or estimated for 2005. Many thanks! --08:58, 30 October 2005 (UTC)

The first paragraph of the WHO malaria site says "more than one million people...a year." Hope that helps. - Akamad 19:50, 30 October 2005 (UTC)

Thank you! A more specific figure would be cool, but that'll do in the absence of one! Thanks again --19:57, 30 October 2005 (UTC)

Yeah I imagine getting accurate numbers would be difficult, this WHO document (PDF) puts the number of deaths betwen 0.7 and 3 million (page 13). Akamad 02:57, 31 October 2005 (UTC)

Wow – that's great! I can just discuss the difficulty in gaining accurate numbers. Thanks again for your help! --08:06, 1 November 2005 (UTC)

Enthalpy

What is the ΔH_c of Methanol and Hexane? smurrayinaHauntedHouse...Boo!^{(User), (Talk)} 10:24, 30 October 2005 (UTC)

• For methanol, by calculation, I get −726.8 kJ/mol. I don't have Δ_fH for hexane handy at the moment so I can't do the calculation there. You can find measured values at the Linstrom, Peter J.; Mallard, William G. (eds.); NIST Chemistry WebBook, NIST Standard Reference Database Number 69, National Institute of Standards and Technology, Gaithersburg (MD) . Physchim62 (talk·RfA) 16:47, 30 October 2005 (UTC)

Water on Earth

Has all of the freshwater on earth already been drunk before by animals and humans? That is, is all drinking water purified urine? Jazz1979 10:45, 30 October 2005 (UTC)

Nearly certainly, considering that land animals have been around for the past several hundred million (a billion even? Don't listen to me, I'm not a geologist nor a biologist) years. Look at it this way – something that's passed through so many kidneys has to be clean, right? -Sam Pointon 12:19, 30 October 2005 (UTC)

I think the general idea is that life has been on Earth for over 3 billion years -- although most of that time life was just simple organisims like bacteria. Given that idea, I would say that almost all of the water on the surface of the planet has been used by some organisim or another, although probably not by humans (a realitvley young species).

But it's not just your drinking water here, you breath in water vapor with every breath, so you're drinking that ex-urine too.  ;-) --Quasipalm 16:15, 30 October 2005 (UTC)

"You are made of star dust !" – Carl Sagan

"You are made of dinosaur poop !" – Me – StuRat 16:29, 30 October 2005 (UTC)

If there's some water somewhere on Earth that has escaped contact with life (a real eternal permafrost?) then it's quite unlikely that you will get in contact with it. By the way, the purification is most likely done by evaporation; cloud creation over seas > rain over land > your drinking water. But does this mean that all the seas are concentrated piss? DirkvdM 08:22, 31 October 2005 (UTC)

In a way, but things like urea and uric acid are also broken down by other processes in the oceans. That might be one reason for the higher concentrations of "impurities" in the oceans, such as salts, however. I'm not sure if it would be significant relative to the contribution of impurities from other sources, however. StuRat 00:02, 1 November 2005 (UTC)

Most of the salt in the oceans is from rocks and underwater caves that were joined into the ocean, salinating it at some point or another. Most of our salt comes from unadulterated salt mines that haven't joined the main oceans. The salts of living things came from these places and were incorporated by them metabolizing the salts. I think a very, very small fraction of the salt in the ocean came from living things because living things tend to recycle their own substances (human->cow->grass->human/cow/animals/feces/etc). Rarely do other creatures absorb salt and compounds from pure sources.--Screwball23 ^talk 04:24, 2 November 2005 (UTC)

But then where did those salt deposits ome from in the first place? Dried up seas? But before that, where does salt come from? DirkvdM 09:30, 2 November 2005 (UTC)

Salt is a chemical compound with an anion and cation. Sodium chloride is but one of the types of salts out there. Most salts contain a halogen and an alkali metal but think of them simply as a metal and a nonmetal bonded. If you want to know where the salt on earth came from, you must remember that the salt on earth is as old as the earth itself, and was present when the earth was still molten-hot. As for which came first, the salt or the seas, the answer is the salt. The salt chemically bonds faster than a hydrogen-oxygen reaction, so salt was bonded faster from gaseous compounds. The salt was melted into liquid-hot magma and was going around the earth until it cooled. It cooled into a solid and later, water cooled to a liquid, and water naturally dissolved the salt. However, most of that salt was in underground pockets while the water only existed on the coolest surfaces of the earth, so the oceans became more salty as time progressed. The salt-mines are just pockets of salt in our bedrock that happen to be near the surface or were not dissolved by the seas.--Screwball23 ^talk 15:20, 2 November 2005 (UTC)

Carbon redux

For context, see #Carbon, above.

Okay, I'm curious... how is carbon used in dentistry? ‣ᓛᖁᑐ 13:00, 30 October 2005 (UTC)

I believe dental drill bits are often diamond dust coated. (Note that the article on dental drills didn't exist when I wrote that list, so I decided to just link to dentistry and let the reader puzzle it out. I've since started the article; corrections and improvements are welcome.)

The list actually happens to be quite comprehensive, as it includes three different carbon allotropes plus organic compounds. Probably not what the teacher expected, though. —Ilmari Karonen 13:29, 30 October 2005 (UTC)

I don't have a clue how elemental carbon would be used in dentistry, at least the way it is practiced in the United States. This is a stretch, but some water purification systems in dental equipment may contain activated charcoal filters.

Of course, carbon is part and parcel of all organic life, which pertains to dentistry, as it does to all the health professions. Dental burs ("drill bits") may be composed of carbon steel, and are tipped with tungsten carbide. But elemental carbon? I don't think so... --
Mark Bornfeld DDS
dentaltwins.com
Brooklyn, NY 21:37, 30 October 2005 (UTC)

Laptops and Notebook Computers

Why don't laptops and notebooks have VGA screens?

• What do you understand by "VGA"? Viewed as a standard size in pixels, most laptop computers have a better-than-VGA screen, just like most desktop computers. Notinasnaid 13:44, 30 October 2005 (UTC)

• If you're asking why they have LCD rather than CRT screens, it is because of the size difference between the two. --Fastfission 14:38, 30 October 2005 (UTC)

I get a 1600x1200 resolution on my laptop, which is well beyond VGA. StuRat 16:26, 30 October 2005 (UTC)

The VGA standard resolutions were set forth by IBM and the release of the IBM PS/2 in 1985. The Article VGA Explains the resolutions. VGA is small and old. VGA was superceded by a fast growing industy to be named sVGA. Which, since it was a lot vendors haggling, and bragging, is not so well defined as VGA.

1. VGA (or Cathode Ray Tubes CRTs )screens are heavy compared to LCD or Liquid Crystal Displays.
2. Some early portable computes had CRT displays. ( most notably, the Osborne 1, and the IBM PC Portable, but quickly became obsolute, when the company or competition adopted LCD displays ) Artoftransformation 09:47, 2 November 2005 (UTC)

Spanning tree

Not really sure where to put this but the following anon 84.59.113.235 has created three articles on spanning trees that look like complete gibberish. Can someone expand them into encylopedic stubs? Theresa Knott (a tenth stroke) 17:04, 30 October 2005 (UTC)

How about a link so we can find it ? -> spanning tree. StuRat 20:47, 30 October 2005 (UTC)

Do you mean the mathematics or the network protocol article or both ? StuRat 20:51, 30 October 2005 (UTC)

She meant the articles in Category:Spanning tree. --R.Koot 21:13, 30 October 2005 (UTC)

I see what you mean, those 3 articles do need work. StuRat 21:55, 30 October 2005 (UTC)

I'll see if I can expand them a little after my exam week. --R.Koot 23:23, 30 October 2005 (UTC)

Methane

Hello, this is related to another question I saw on another page. My question is I know that the chemical methane is added to the nicotine leaves to aid in burning. Would the leaves be able to burn or burn well without this chemical and how is it that the smoke doesn't blow up since it is a dangerous chemical when someone lights up? Also, what other chemicals besides methane are added to the niotine leaves not the paper to make it burn and burn slowly?

It has to do with the concentration of methane. Too low of a concentration just provides a nice even burn. At a higher concentration you can get an explosion. At the highest concentrations you no longer get explosions due to a lack of available oxygen, interestingly enough. StuRat 20:42, 30 October 2005 (UTC)

Potassium nitrate is added to cigarette tobacco in many countries to make it burn faster and to make it harder to extinguish. There used to be special cigarettes for sea fishermen which had a particulerly high potassium nitrate content and which were virtually unextinguishable even in a gale! Physchim62 (talk·RfA) 10:15, 31 October 2005 (UTC)

Without the methane and excluding the paper would the dried tobacco leaves be able to burn or are they dependent on the methane to burn?

You can certainly burn tobacco without added chemicals, as smoking predates all those additives by centuries. A pipe was typically used, which retains much of the heat of combustion and offers some protection from wind and moisture which might tend to extinguish the tobacco. StuRat 23:53, 31 October 2005 (UTC)

I thought the Indians used cigars (putting the burning end in the mouth). The thickness of the cigar would probably help in keeping it burning. DirkvdM 09:22, 1 November 2005 (UTC)

What about other chemicals like ethylene or butane are those added to cigarettes and do those also aid in the burning of the tobacco leaves? Also how are these things added, I read about how tobacco companies shred the dried leaves then they add the top dressing as they called it by spraying it on, but that also includes strange things such as chocolate and honey and coffee, how do these things along with the chemicals remain on and not make the leaves soggy and the chemicals not be watered down so they work effectively?

Anything highly flammable would help them burn better. As for getting soggy, the leaves are cured before being made into cigs. One method of curing is to heat the leaves to drive off excess moisture. StuRat 17:46, 1 November 2005 (UTC)

This question goes back to the original question about methane. You mentioned that a very low concentration of methane helps slowly burn without being dangerous, how much would be considered a low concentration and what concentration leve does it get dangerous?

Lungs

What is the anatomical position of the lungs?

In the chest in most of us. If you are writing a xenobiology report for your home planet, you can say that humanoids have lungs within the thorax that take up most of the space within. They are cephalad from the diagphragm and caudad from the neck. They surround the mediastinum. And please emphasize in your report that humanoids taste really bad. alteripse 18:53, 30 October 2005 (UTC)

That somebody doesn't know where their lungs are just takes my breath away. StuRat 20:36, 30 October 2005 (UTC)

<sigh> lame jokes make me gasp Theresa Knott (a tenth stroke) 22:25, 30 October 2005 (UTC)

If you don't think that's shocking, according to the November, 2005 American issue of Playboy, "20% of Americans think the sun orbits the earth. 17% know the earth orbits the sun but think it does so every 24 hours, not every 365 days." No, I don't know where they got their data. Dismas|^(talk) 22:37, 30 October 2005 (UTC)

95% of those who answered everything correctly didn't notice that they are visitors from Europe, Africa, Asia, Oceania or South America. :) Playboy rules! Now give me a playmate. -- Toytoy 06:35, 31 October 2005 (UTC)

I think they got them from the NSF's Science and Technology Indicators surveys. Note the charts to the left; sadly, Europeans don't do significantly better or worse than Americans---more Europeans think lasers work by focusing sound waves, whereas more Americans think that the earliest humans lived at the same time as the dinosaurs. grendel|khan 18:01, 31 October 2005 (UTC)

Bad survey technique. Those guys were distracted by the pictures. alteripse 00:36, 31 October 2005 (UTC)

Still, it was a rather titillating survey. StuRat 23:49, 31 October 2005 (UTC)

With out stupid people there would be no smart people--Eye 22:53, 31 October 2005 (UTC)

Or vice versa. DirkvdM 09:24, 1 November 2005 (UTC)

Integration of Second Derivative

I have that ma=-(k squared)/(x to the third). And you have that a is the second derivative of x with respect to time. I need to fine x of t, x(t). How do I do the integral of a second derivative to get x of t? Confused. Please help.

$ma=-{k^{2} \over x^{3}}$

This is a differential equation, since $a=d^{2}x/dt^{2}$.

Try repeated Separation of variables and integration.

Separated, this is:

— Sverdrup 18:47, 30 October 2005 (UTC)

Actually, I don't think you can apply that trick, at least not easily, for second derivatives. I'll explain momentarily. -- SCZenz 22:42, 30 October 2005 (UTC)

Well, I got distracted, but I'll explain now. First of all, $d^{2}x\neq (dx)^{2}$, but anyway let's try to apply the trick twice and see what happens. We have, with f(x) = -k²/(mx³),

${\frac {d^{2}x}{dt^{2}}}=f(x)$

Thus

${\frac {d}{dt}}({\frac {dx}{dt}})=f(x)$

Which gives

${\frac {1}{f(x)}}d{\dot {x}}=dt$

You might hope that your variables are now separated, but in fact ${\dot {x}}$ = dx/dt is a function of both x and t so they aren't. I don't know of a way to apply the trick to second derivatives. Maybe someone who knows more math than me can comment further. -- SCZenz 07:52, 31 October 2005 (UTC)

Long time since I did this, so almost certainly wrong:

${\frac {d^{2}x}{dt^{2}}}={\frac {dv}{dt}}=({\frac {dx}{dt}})({\frac {dv}{dx}})$

By basic chain rule. So you then have 1/2 m v^2 on one side and the integral with respect to x on the other. Physically, think of it as calculating the kinetic energy gained/lost as you move a distance under a given force. You can then get x(t) by direct integration, if you do some clever square rooting and rearranging.--Fangz

Interesting. Should've thought about it longer, it felt quite wrong actually. I recognize what Fangz does though, that must be how I solved this kind of problem in my mechanics classes. Hmm. I really need to study this a bit more. Sorry for the bad advice. — Sverdrup 19:15, 31 October 2005 (UTC)

This is basically good, but needs a slight clarification...( PLEASE! Someone tell me how to write an intergral sign??!)

If we take that last equation and integrate all parts...

$I2(frac{d^{2}x}{dt^{2}}=$Now I see the problem!

$ma=-k^{3}/x^{3}.a=a(t)m=K,k^{3}=K$

rewrite it as $a(t)x^{3}=(k^{3}/m)$Ahahaha!

Now Integrate all the parts using the varible t. ( Hint: you must substitute for a as fuction of t (See the first hint in this section...)

Apply Fangz trick twice and you'll get the answer straight-away. However, Wikipedia is not the place to ask for assistance for homework problems ... linas 04:28, 1 November 2005 (UTC)

Well, wikipedia isn't the place to get people to do homework for you. But I don't think there is anything wrong with people discussing homework problems here, so long as you understand any ideas suggested, not just copy down the answer wholesale. If it's just discussing approaches, then it's part of the learning process, and there is nothing wrong with that. It's identical to asking your teacher for a hint, asking schoolmates, or looking up material in the library or a textbook.--Fangz 17:43, 1 November 2005 (UTC)

global warming

why is the % of carbon dioxide in the atmosphere so small?

Take a look at the article Earth's atmosphere. The atmosphere was primarily composed of carbon dioxide and water vapour. As the planet cooled, the water vapour condensed into oceans and seas, and the water in turn dissolved most of the carbon dioxide. The evolution of photosynthesizing plants resulted in further reduction in CO₂ levels. -- Canley 22:31, 30 October 2005 (UTC)

Long ago the evil chloroplast-bearing plants took over the earth and consumed all the CO2, emitting all this corrosive oxygen. If we all breathe hard enough, maybe we can reverse this state of affairs, lower the O2 level, and raise the CO2 level again. alteripse 03:28, 31 October 2005 (UTC)

No worries, we've already invented cars to do that for us. Aren't we clever? DirkvdM 08:35, 31 October 2005 (UTC)

In addition, in case you are wondering, the significance of this with regards to the current global warming situation is that we don't need to worry about destroying the world, or indeed all of life, only ourselves and our current civilisations.

Indeed. Destroying the Earth is harder than you may have been led to believe. grendel|khan 18:08, 31 October 2005 (UTC)

That's about destroying the Earth as a planet. But even 'just' destroying all life on Earth would be a job that's way beyond the present capabilities of mankind. There's always at least some bacterium that will survive, from where things could start all over again. But even exploding all available nuclear weapons (strategically placed, with this purpose in mind) would constitute little more than a major blip in the evolution of life on Earth, I assume. It would take much less to ruin things for ourselves, though. And not just for our offspring, but also for our generation. An increase of the average temperature with a few degrees is expected for the not too far future and if you look at a map of the average temperatures on Earth, that would mean habitats shifting towards the poles by hundreds or thousands of kilometers. At least, the temperature bit of the habitat. Other aspects of the habitat will likely not be found at the new location, so many species will get extinct. This sort of thing has happenend before, but never at this speed. Evolution takes time and most species cannot adapt that fast. Mankind can help where foodcrops are concerned, but the adaption will also take time – eg farmers need to learn about new crops, also in poor countries where spreading the needed info will not work very efficiently. So mass starvation will result (which will also affect those safely in the West). The again, if those farmers in poor countries would get the help they need to survive, that might give those countries the boost they have needed for so long. But I wouldn't count on this happening. Also, local temperature change may (and often will) be much greater than the world average. And temperature change is just one thing. Rainfall patterns will also change. Everything will get messed up. Globaly and at an incredible speed. Be afraid. Be very afraid. DirkvdM 09:40, 1 November 2005 (UTC)

Hospital

What is a hospital district?

• It's the district covered or serviced by a hospital. So if were sick or injured in the Union County Hospital District in Illinois, you would be taken to the Union County Hospital. -- Canley 05:02, 31 October 2005 (UTC)

October 31

Solution

How do I find the mass of a solution given the mass of the solute?

You need the concentration of the solution. Perhaps molarity or molality, depending on what the homework problem is asking. Titoxd^(?!?) 02:19, 31 October 2005 (UTC)

You also need to understand the principle of conservation of mass. Note that volume is not conserved. Physchim62 (talk·RfA) 10:18, 31 October 2005 (UTC)

I don't think it is entirely certain that mass is conserved when something is dissolved. In most cases, probably, indeed I expect that's what our questioner requires, but what if you are trying to dissolve calcium carbonate in a weakly acidic solution?--137.205.18.131 13:57, 31 October 2005 (UTC)

Remember that mass is conserved in a closed system – in this case you need to take into account the liberation of the carbon dioxide. If you don't, well, obviously mass isn't conserved. --216.191.200.1 14:18, 31 October 2005 (UTC)

"For every chemical problem, there is a chemical solution." – StuRat 02:44, 1 November 2005 (UTC)

UTS of indented prestressing steel wire

As per different standards of indented prestressting steel wires, it is seen that as the diameter of wire increases Ultimate Tensile Strength (UTS) decreases. As an example minimum UTS of 4 mm dia wire is 1715 N/sqmm while that of 5 mm dia wire is 1570 N/sqmm.

When enquired from different manufacturing agencies, it is learnt that while drawing from same parent material, by cold drawn process, Breaking load decreases which is not in the same propotion as that of diameter. Since UTS = Breaking Load/Area, it varies.

Why the Breaking Load of these steel wires does not decrease in same propotion as that of diameter of the steel wire? Is there any molecular changes involved in it, if so what is that?

MALOY NANDI

It's not directly related to the diameter. Nor is there any kind of molecular change cause by an increase or decrease in diameter. See Strength of materials, and also check out Solid Mechanics on the Wikibooks site. Proto t c 09:53, 31 October 2005 (UTC)

Then why does UTS decreases with increase in diameter of Plain Drawn Steel Wire?

MALOY NANDI

It's to do with its Young's modulus, and the relationship of stress and strain. The relationship is different for every material. Read the article on the Wikibooks site. Proto t c 12:30, 31 October 2005 (UTC)

From the Australian Standards, the brekaing load for 7 mm and 5 mm wire is proportional to diameter squared. Also, the 7 mm wire has a higher UTS than the 5 mm wire. Are you sure you are just talking about wire and not strands and bars? I'd like to discuss this further.--Commander Keane 18:05, 31 October 2005 (UTC)

As per Indian Standard Code (which are practically photocopy of British Standard), minimum Ultimate Tensile Strength (UTS) of different sizes of steel prestressing wires are as following –

Dia of wire UTS (N/mm2)

• 2.5 mm 2010
• 3.0 mm 1865
• 4.0 mm 1715
• 5.0 mm 1570
• 7.0 mm 1470
• 8.0 mm 1375

It is seen from above table that UTS of a plain drawn steel wire decreases with increase in diameter of the wires. What is the reason for this variation if parent material remains same, with no change in chemical properties?

It is understood from the discussion with different manufactures (TATA Steel), during cold drawing process Breaking Load decreases, but not in same proportion, with decrease of diameter of wire. What is the reason behind it and what changes are taking place within the hard drawn steel?

MALOY NANDI

I don't know mate. I'll look into it, but it might take me a couple of weeks. I agree that your values closely match the Australian Values (although we have some variation, ie we can have 7 mm wire with UTS of 1800 MPA or 1870 MPa or 1950 MPa.) My guess (which might be wrong) is that the larger (surface area)/(volume) ratio for smaller wire allows better cooling of the wire during manufacure. The larger diameter wire has a smaller (surface area)/(volume) ratio – and the steel in the middle of the wire stay molten while the outer steel is already cool. This creates internal strains which reduce the strength of the wire. Only a guess though. --Commander Keane 06:35, 3 November 2005 (UTC)

There is no heat process involved in cold drawing process. Larger dia wire (e.g. 8 mm) is passed through various dies of smaller diameter to get smaller dia wires (e.g. 4 mm/5mm etc.). Resultingly UTS of wire increases.

MALOY NANDI

I give up. You can try emailing someone at your nearest university.--Commander Keane 16:25, 3 November 2005 (UTC)

Electron mass

I understand the electron mass is the best measured particle mass, to an accuracy of some 10 digits. I am wondering if there have been any attempts to test whether the mass is in fact a constant, or if it is changing over time (if the mass changed significantly over cosmological times, there could conceivably be a change in the 10th digit over a few decades or so). And, which property is actually measured in this precise number of e mass: is it the relation to the proton mass? Which definition of the kg is intended when they say m=0.510998918(44) MeV/c**2 ? Would a change in elementary particle mass that leaves the ratio of e to p masses intact even be registered, or would that be equivalent to a change in the gravitational constant? Baad 08:12, 31 October 2005 (UTC)

The accuracy of the measurement, according to the particle data group, has improved by a factor of 5 since 1999 and by a factor of 50 since 1987 [77]. Thus if there were changes in those last few digits over decades we wouldn't have seen them. All the measurements listed since 1987 are easily consistent within 2 sigma (i.e., close enough that they don't indicate any inconsistency), and presumably before that even fewer digits of precision are available.

The most accurate measurements are made relative to the mass of a carbon-12, which is defined to have a mass of 12 atomic mass units. The measurements in electron volts are less accurate, because the conversion involves the elementary charge, which is not as accurately known as the masses themselves. Proton mass measurements are independant and have the same limitation [78]. They're not measuring the electron mass over the proton mass at all.

As for your question about whether a change that kept the ratio intact could be registered, that would depend on what else changed—assuming all particle masses scaled in the same way but other laws of physics left intact, the changes would still register because some of the mass in carbon-12 is determined by the nuclear binding energy (and thus by the nuclear force), so its mass wouldn't scale in quite the same way as the proton or electron. (In fact, if you only changed the masses of elementary particles, the proton mass wouldn't change much at all, because almost all of its mass comes from the strong force and not from the masses of its constituent quarks.) Let me know if you have more questions. -- SCZenz 08:37, 31 October 2005 (UTC)

interesting... but, on second thoughts, I assume changing e or p masses are not an issue anyway, since they would register in the H/He emission lines of ancient galaxies? Or are these independent of particle mass? Baad 09:05, 31 October 2005 (UTC)

They depend strongly on the electron mass, but only a little on the proton mass. -- SCZenz 09:09, 31 October 2005 (UTC)

ah, but on third thoughts, since the known 'contemporary' frequencies are presupposed to estimate the Hubble constant, that's not true; if the masses changed, we'd be wrong about the age of the Universe, but we couldn't tell. Baad 09:14, 31 October 2005 (UTC)

There's more than one source for the age of the universe; having something odd like that screw up our ideas without us realizing it would be very difficult to set up in a self-consistent way. -- SCZenz 09:19, 31 October 2005 (UTC)

well, the age of the Universe is certanily not known to ten digits' accuracy :) so if the mass of the electron changed, say, 10% over the last ten billion years, I doubt that we would be able to detect it. Baad 09:53, 31 October 2005 (UTC)

The problem is that electron mass is tied up with a number of other things – according to certain theories, it is a result of deeper principles. (maybe. I'm fairly uncertain here) Even the possibility of electron mass changing would mess up a great number of things. --Fangz 20:52, 31 October 2005 (UTC)

If I got this correctly, nobody has an inkling of why particle masses are what they are. People have ideas of why they are massive at all, but no known principle would prevent an electron to have a mass of 0.6 instead of 0.5 MeV. The whole particle zoo is completely descriptive, even the three 'generations' are unexplained, for all we know (I think...) there could be five or nineteen. particle masses shifting over time would thus in a certain sense be a relief, because it would rid us of the obligation to explain their seemingly random values. We would of course have to come up with an explanation of why and how they shift. This is, at least, what you get from the Standard Model. I have no idea what sort of advanced ideas may be brewing in GUT territory. 23:31, 31 October 2005 (UTC)

Indeed, these are all open questions. There are also a lot of theories between the Standard model and Grand Unified Theory, such as Supersymmetry, large extra dimensions, and technicolor (physics). Most of them don't explain why particle masses are what they are, although String theory has a mechanism for doing exactly that—if only they could calculate anything, and find which string theory to use! ;)-- SCZenz 23:50, 31 October 2005 (UTC)

I vaguely remember reading about some confusing atomic spectral data from extremely distant quasars (unresolved distant galaxies) indicating that the fine structure (or hyperfine structure??) structure seems to have changed, as compared to what it is in modern times. I don't know if other astronomers confirmed this or not, and am not clear of what the other interpretations are. However, changing fine structure indicates that either the electron mass or the electron charge or both are changing. Theories to explain this will be all over the map; it will be at least decades if not half-a-century to narrow things down for "extreme physics" questions like this. FWIW, the variation of Kaluza-Klein theory as practiced by Paul Wesson et al. has masses changing by about 10% over about 10 billion years. Here's the fun bit: in their theory, the origin of mass is due to geometry of the 5D KK space, and all sorts of funny things result: for example, mass change is equivalent to Hubble expansion. Note also, changing fine-structure consts does change biochemistry, among other things ... linas 04:45, 1 November 2005 (UTC)

I am intrigued that the order of magnitude you quote (10% over about 10 billion years) should correspond verbatim to what I've forwarded for the sake of argument above.... Anyway, I suppose your quasar article is what I was looking for, so if you have the reference, please let me know. I'd also be interested in the "mass change is equivalent to the Hubble expansion" reference. Baad 12:37, 1 November 2005 (UTC)

Enzymes

Why are enzymes inactivated at low temperatures???

See enzymes. Proto t c 09:41, 31 October 2005 (UTC)

Enzyme activity depends of kinetic energy and the movement of molecules. At low temperature there is less movement and less enzyme activity. If you totally prevent molecular movement you can stop enzyme activity. Sadly, neither the enzyme article nor even the Enzyme Kinetics article describes the effect of temperature on enzymes activity. There is a tiny bit at Rate of enzyme mediated reactions. Here is some more information (about half way down the page). A few more details. --JWSchmidt 14:22, 31 October 2005 (UTC)

Flu jab

Why can't you take the flu jab when you are sick?

Because it gives you a very mild case of the flu, and if you're already sick, it can be exacerbated into a more serious case as your body's defenses are weakened. Proto t c 09:43, 31 October 2005 (UTC)

Not quite. For most people, it doesn't make you sick. The two reasons are (1) liability and safety, and (2) the theoretical concern that effectiveness may be reduced. If a person is sick, he can be sick in many ways and there are many different outcomes (from full recovery, to complicated illness, to death). Although it is extremely unlikely that this type of intervention would change the course of a current illness, the doctor caring for the patient and the person or organization or corporation providing or making the flu shots do not want another variable added in to the illness and especially do not want the flu shot blamed for the outcome of the illness. A lesser reason is that during the acute phase of another viral infection, the immune response to a flu shot might be altered in such that the long term protection response may be lessened. This is mainly a theoretical concern and has not been proven or even well-studied. alteripse 12:17, 31 October 2005 (UTC)

I assume that "flu jab" is a British term meaning influenza vaccination. Some anti-viral vaccines contain active viruses – almost always a virus strain that does not cause illness. Other anti-viral vaccines contain inactivated virus or purified viral proteins. The purpose of flu vaccination is to expose the body to flu virus proteins that will stimulate the immune system to protect the body against future infection by flu virus. Generally, you want to be vaccinated several weeks before being exposed to a flu virus that could make you get sick. Once you have the flu, your body is already being exposed to the proteins of the flu virus and your immune system is responding to defend you. Adding a flu vaccine to your body would not be of any significant additional advantage. The flu virus that is making you sick is itself acting like a very efficient vaccine in the way it stimulates your immune system. The problem is that it takes about a week for your immune system to respond enough to win its battle against the virus infection. If you were vaccinated before being infected by a flu virus, then the immune system of your body will contain things like memory B cells that will make it easier for your body to react quickly to defend against the infection. --JWSchmidt 13:58, 31 October 2005 (UTC)

Chlorophyll

Why is chlorophyll green in colour??? I mean why it has to be green to be able to absorb light?

(From the article) Chlorophyll absorbs mostly in the blue and to a lesser extent red portions of the electromagnetic spectrum, thus its intense green color. This applies to plant chlorophyll. Chlorophyll does not always have to be green – there are also purple bacteria, which use bacteriochlorophyll, which absorbs infrared light. Proto t c 09:48, 31 October 2005 (UTC)

The long answer is that (a) it absorbs more or less the right band of energy – the green colour is light that is not absorbed, and well, green light isn't very common on earth, (b) it coincidentally works chemically with photosynthesis, (c) it just happens to hold the right balance between cost of synthesis and and efficiency for most plant life, and (d) it happened to be picked early on by evolution, and there is no real selective pressure to change it. At least, that's my not-very-rigorous opinion. --Fangz

Light in the green wavelength is exactly as common as light in any other visible wavelength. Tempshill 22:15, 31 October 2005 (UTC)

1) "it just happens to hold the right balance between cost of synthesis and and efficiency for most plant life" This does not sense as far as i can tell. If the cost is the synthesis of chlorophyll, and it can absorb many photons, why is the efficiency relevant?

2) it happened to be picked early on by evolution, and there is no real selective pressure to change it. This does not seem right either. There are accessory pigments in plants that are not green. Carotenoids and xanthophyls are red and yellows, hence the autumn colours. It seems evolution has and does use other variations if needed. Also chorophyll a and b have different, non overlapping absorbtion spectrums suggesting that the absorbtions characteristics are not fixed and someone has already mentioned the bacterio chlorophylls that are purple and absorb mostly in the infra red ONLY. David D. (Talk) 22:46, 31 October 2005 (UTC)

In fact, green light is, in a sense, more common than other colors. The peak of the sun's black-body spectrum, around 500 nm, is in the "green" range, although the sun emits enough light at other wavelengths to make its apparent color yellowish white. —Ilmari Karonen (talk) 01:07, 1 November 2005 (UTC)

Well, these are just my guesses. If you lot have better ideas, I'm happy to hear them.

This does not sense as far as i can tell. If the cost is the synthesis of chlorophyll, and it can absorb many photons, why is the efficiency relevant?

Evolutionarily, the plant is solving a cost-profit problem. Suppose a 'better' pigment would cost X more in terms of energy, and resources (e.g. minerals, water...), but help the plant absorb a higher proportion of photons, and so a higher proportion of light energy. The plant evolutionarily 'chooses' depending on whether the gain outweighs the cost. It may just happen that for the majority of environments, chlorophyll is simply the best solution.--Fangz 02:18, 1 November 2005 (UTC)

Or it may simply be that photosynthesis is a hard problem. There are very few basic types of photosystems in use on Earth, and at least all the really good ones appear to have evolved from a common ancestor. It may be that, in the time life has existed on Earth, green just happens to be the best evolution has been able to come up with so far. —Ilmari Karonen (talk) 10:38, 1 November 2005 (UTC)

The only cost/benefit that I can think of does not relate to the chorophyll. Each photosytem that absorb photons has hundreds of pigment molecules, including carotenoids. Photons absorbed in the spectrum transfer energy to the reaction center and excite the electron to an electron acceptor molecule. Since one reaction center has coopted many pigments it is rare that the supply of electrons is so limited that even the green light has to be harvested. There are exceptions such as shade tolerant plants that see a few speckles of sunlight, their leaves are often very dark green (almost black). Their existance would argue that the need for more photons is not limiting full sun plants and hence losing the green photons does not enter the cost benefit analysis. The only cost I can think of for absorbing green is that the plants heat too much from the inefficient transfer of energy to the photosystem reaction center (energy is lost as heat which is bad for a leaf). However, if that was a real cost it would be the blue end of the spectrum a plant would want to reflect since those photons are higher energy than the green photons. In fact, some plants do have waxes on their leaves to reflect blue light to reduce the heating. In summary, the best argument for a cost benefit argument is the overheating problem from harvesting too many photons but this seems to relate to the plant as a whole NOT to the synthesis of chlorophyll. In general there is no need for a better pigment as there are several pigments than can be combined to adjust the total absorbtion to suit the plants specific environment. David D. (Talk) 12:21, 1 November 2005 (UTC)

• Let's not forget that it is entirely possible chlorophyll is not the optimal solution. It may be that this is not what works best, but what has worked well enough for life to evolve to this point. Evolution is an ongoing process, so it is entirely possible that something may replace chlorophyll as the dominant plant photorecptor someday. Johntex\^talk 20:27, 3 November 2005 (UTC)

Water

Does water/moist conditions promote hair growth?

No. Unless it contains a lot of testosterone, and you drink it. Proto t c 09:44, 31 October 2005 (UTC)

Perhaps what you are thinking about is the lengthening of hair. Hair does seem to become longer when it is wet or humid. It doesn't grow or become longer, it only stretches temporarily.--Screwball23 ^talk 04:29, 2 November 2005 (UTC)

hair

What is the purpose of pubic hair growing around the reproductive organ of both man and woman?

See puberty and pubic hair. Proto t c 09:44, 31 October 2005 (UTC)

I would say two purposes:

Lubrication. Places where rubbing occurs could lead to abrasions. Hairs reduce the friction. To test this, rub two hands together, then put some hair between them and rub again. It should be easier afterwards. Armpit hair serves the same purpose.

Age marker. Body hair is a way to mark that a person is of reproductive age, which is an important thing for any species to be able to distinguish. This explains why young children don't have body hair. Of course, there are many other age markers as well.

StuRat 16:59, 31 October 2005 (UTC)

I would have to disagree with the lubrication remark. There are fluids both the male and female body release to accomplish lubrication. We might call it pre-ejaculatory fluid. Therefore StuRat, I believe your friction argument has no bearing here. As for it being an age marker: that's just more of an unrelated side-effect. In my opinion it has more to do with heat loss. One reason why the hair on our heads has remained throughout evolution has to do with the fact that we lose a large amount of heat out of the top our heads. This is one reason why beanies are so effective. I think this point carries over to our genitals as well. Also, major arteries run through the armpits out into the arm, so I believe my heat loss argument also applies to armpit hair. Remember, at one point in time our ancestors were completely covered in hair, even at birth. Once we started wearing animal furs/clothes to endure the ice-age and the cold northern winters, over millions of years body hair became more of a nuisance rather than a nessecity. It is possible that in another million years or so our bodies will be completely devoid of hair. So long story short: it is simply a way to minimize heat loss. - Cobra Ky (talk, contribs) 19:41, 31 October 2005 (UTC)

Pre-ejaculatory fluid is not a form of lubrication for the joint. I hope you haven't been using it for lubrication of your groin, because it isn't too wise. The use of hair is not for your sexual lubrication in this case. Our discussion has come to a very good consensus (implicitly of course) that sexual relations and pubic hair aren't closely related.

Secondly, you cannot predict evolution based on simple extrapolation. You can reason all you like, but remember that evolution (especially human evolution) is extremely unpredictable. What I'm referring to is your statement; you have no real facts to say that humans will become hairless in the future. Hairless is more efficient in a cold environment and is matching to the patterns we've seen so far, BUT how can you say that humans actually will? The same could be said of large muscles. People would think that they will become small and shrimpy in the future. That is only a thought, not a fact. How do you know that large numbers of people will become sedentary, computer-using vegetarians with no hair and enormous skulls? You only think based on what you've seen the recent trend is. And you say you have the knowledge to say you know what people will look like in millions of years? I doubt you will know what people will be wearing next year. Human evolution is going to be more complicated than human history. You would be a complete fool if you think you can see the future in a million years. You must remember that the process of evolution will not go on in the pattern you think it will just because you think it will, it will most likely surprise you to know what the world looks like in the future.

As for the heat-loss argument, I would like for you to refute my evidence below. The aforementioned principles underlying pubic hair are very important. Simply because humans had more hair before and now have less doesn't mean that it is the most desirable and advantageous. Indeed, you might think that clothes put some "survival of the fittest" pressure on humans to lose all their hair. Or you might think that people love change and "advancement" so much that they will surely lose their hair in the future. Evolution is far different from the trends and fads you are thinking about. Evolution is a long-term process--don't think you can see it a million years ahead of time.--Screwball23 ^talk 03:11, 4 November 2005 (UTC)

I don't believe in the heat loss explanation – if that was true, then an external scrotum and pubic hair would work at cross purposes. Everything2 has an explanation – which you may or may not decide to trust. http://everything2.com/index.pl?node=pubic%20hair --Fangz 20:48, 31 October 2005 (UTC)

Well, reading more into it, there are several resources that confirm the friction argument. But there are also just as many resources that confirm the heat loss argument. Here is just one. Which surprises me that there is no mention of it in our wikipedia article on pubic hair. But there is mention of heat loss in our hair article. My opinion still stands, but I do retract my statements about the friction argument having no bearing. - Cobra Ky (talk, contribs) 20:58, 31 October 2005 (UTC)

This is hearsay, but I recall an American Red Cross pamphlet on survival swimming that claimed the places on the human body where most heat loss occurs are the head, armpits, and groin. Human hair in those locations might be particular to the insulation property of hair. Tempshill 22:13, 31 October 2005 (UTC)

Still, the importance of hair on the head is much greater because it contains the only vital organ outside the torso. And it's not even covered by any substantial amount of fat, so, if it's cold and the head is not covered, loads of heat is pumped up there to prevent instant death. "If your feet are cold put on a hat". It's true, I've tried it. Then again, survival is evolutionary pointless if you dick freezes off (ouch!). DirkvdM 09:55, 1 November 2005 (UTC)

That last mentioning about a frost-bitten penis isn't really very helpful. If heat around the penis was very important, you might have seen hairy penis shafts. Or better yet, hair around the urethral orifices. That would definitely contain heat. It would also create more infections and would lead to wet, cold hairs. It might also create much displeasure during mating. That is probably disgusting to many people, demonstrating that the sexual selection involved would probably be enough social stigma to avoid sexual reproduction of that individual. The heat loss of the penis is great considering that it is an appendage out of the main body, open to the environment, much like a finger. The pubis is actually above the penis, making it very useless for most heating. The testicles, alternatively, favor cold temperatures for maturation of the sperm, leading to the re-thinking of the heat argument. Why would they have hair if heat loss was so important?

The heat loss around the armpits and hair are very good answers, but thinking alternatively, the reason there is so much more heat loss in a pool from these locations would be because the hair causes a build-up of heat.

The reason why we have heat loss may not be the reason why we have hair, it may be that because we have hair, we have heat loss in these regions. We have a great amount of heat loss from many parts of our bodies, but these regions are naturally areas of great heat loss. The brain uses 20% of our metabolic energy. That creates a great amount of heat to be lost, especially in cold weather, when it could easily be contained. The head encapsulates and protects its heat through the use of hair, so I will concede to that, agreeing that the head loses much heat and has hair for that reason.

Secondly, the armpits have hair--and are in a very active joint, so they do have a great amount of hair loss, but they also have large sweat glands. Those regions sweat profusely, showing that they do not need that heat. If they needed the heat, why would they have such large sweat glands? The reason we have large sweat glands (sweating is everywhere) in that area would probably be because the area is a joint and needs to reduce abrasion and could use further lubrication. We could have great friction and would have to callouse the skin around our inner arms in order to function with active arm movement if no hair was there.

The same goes for the pubic hair around the groin. If humans didn't have all that pubic hair around their groin, they would have rough friction between their legs and worse still, their private parts. Consider what friction there would be if a human male had no hair on his scrotum. The constant rubbing against the legs would cause enormous damage, torsion, scraping, and extreme heat in that area. So remember guys, that hair is a God-send. The hair is vital to avoiding friction and creating lubrication in joints, but is not necessary for the head, as it is not a joint but a region of great heat loss. In answer to the criticism, "well, the groin has a great amount of hair and it is losing a lot of heat", I must remind you that the reduction of friction reduces heat too. A joint without hair is a hotter one, disproving the heat loss argument.

The best reason for the pubis we know of at puberty would probably be sexual selection. It demonstrates maturation just as beard growth for males or breast growth for females.--Screwball23 ^talk 02:41, 4 November 2005 (UTC)

Note that the age marker theory is the only one which explains why children lack such hair. Heat loss is actually more of a problem in children, due to their higher surface to mass ratio, so hairiness in children would be a widespread trait if the primary purpose of body hair was heat retention. If body hair was primarily for heat retention we would also expect far more in ethnic groups native to colder climates, and little or none in those native to tropical climates. Also note that facial hair in men is both an age marker and a gender marker. As for the lubrication theory, I wasn't only talking about during sex. Legs rubbing against genitals during walking could produce a rash if no hair was present. Underwear somewhat reduces this problem, however. StuRat 23:38, 31 October 2005 (UTC)

The theories StuRat made were right. Everyone else is thinking too much about the modern-day. There is no real convenience of having pubic hair in your pants rubbing comfortably. How can that convenience evolve? The reason we have hair around our genitals is most definitely sexual selection. No matter what conditions, whether you are blind, in the dark, or messing with someone of the same sex, you can feel the genitals, see/feel the pubic hair and know "Aha! This is a woman! -Then- Aha! This is a mature woman!" If you know that your sexual partner has pubic hair, that person is also capable of having sexual intercourse for the purpose of procreation. In terms of evolution, it stayed because it is necessary for that purpose. Early humans might have mated with younger immature individuals to no avail and produced no offspring. Those that did find the pubic hair did get a good shot at reproducing. If an individual has no pubic hair today, you know that they are incapable of having children because they lack the inherent hormones to begin sexual reproduction. The abrasion theory works perfectly because the groin is a very dynamic pivot point. Movement is going on between all the muscles and joints in the groin. The abrasion is very common and relief must come from hair and sweat glands, of which there is more hair.--Screwball23 ^talk 04:14, 2 November 2005 (UTC)

Does trebble cause more hearing loss than bass?

Which causes more hearing loss, high-pitched or low-pitched sounds? Or, does it not matter? I recently bought earphones that have much more pronounced trebble, but the other night I had ringing ears after using them for an extended period. It made me wonder... --Quasipalm 14:11, 31 October 2005 (UTC)

It depends on how you measure it:

• An equivalent decibel loudness will cause equivalent damage.

• An equivalent energy will cause more damage in the treble range, since treble sounds require less energy per decibel to produce. This means the same energy range will provide a louder sound in the treble range.

You may be encountering the second problem. I suggest you use the equalizer to turn the treble down/bass up to counter this tendency. StuRat 15:43, 31 October 2005 (UTC)

Moreover, be very careful with earphones. It is very easy to set the volume too high. If you already get an instant effect (the ringing ears), then imagine what will happen if you use them regularly all your life. I imagine you might eventually go deaf (to some degree). Earphone#Dangers mentions this but is not specific about the volume levels required for permanent deafness. DirkvdM 10:28, 1 November 2005 (UTC)

Thanks for the replies. I read a bit about the actual levels required for hearing loss on Hearing loss#Noise Exposure. I usually use my earphones on the subway -- they are closed-air so they block out the loud trains, so I figure it's a wash.  ;-) --Quasipalm 14:25, 2 November 2005 (UTC)

"treble sounds require less energy per decibel to produce"

Since when? Omegatron (talk) 19:58, 3 November 2005 (UTC)

axiom of regularity

The axiom of regularity

Axiom of regularity (or axiom of foundation): Every non-empty set x contains some element y such that x and y are disjoint sets.

Disjoint: Maths (of two sets) having no members in common (Collins Dictionary)

This makes no sense to me. How can x and y have no common elements if x contains y. Surely y is a common element.

Danny Ryan

See our article at Axiom of regularity. It really means alot less than you think it does. As a set, x and y share no elements. (If you choose the right y) I.e. y doesn't contain some element that is already contained in x. Which, in a simple set, is fairly obvious if y isn't itself a set.--Fang

Consider the set x={ {1,2} , 3}. x contains two elements, 3 and {1,2}. Both of them are disjoint with y, since they contain no common elements. {1,2} contains 1 and 2, while x does not. 3 is a number and so doesn't contain any elements. According to regularity, all sets work like this. For an example of a (hyper-)set that does not satisfy regularity, consider z={{{{....}}}}. Note that z={z}, so the set and its element are not disjoint. Regularity ensures that sets don't have infinite nests of subsets. -Lethe | Talk 15:25, 31 October 2005 (UTC)

physics

how do i get contacted with physics sicentist so that i can solve my queries regarding physics problems. i am pursuing my phd in this field and i want answers that i am facing it difficult to be answered. —Preceding unsigned comment added by 202.92.68.98 (talk • contribs) 08:36, 31 Ocfghdfthjtfgju dfhtfu ysrthhtober 2005

are you serious? You are pursuing a phd in physics, and you are not in contact with any physicists? that sounds pretty hopeless to me. 83.77.216.101 15:40, 31 October 2005 (UTC)

If you are serious and not an advocate of an original theory (the world abounds with people claiming to have proven Einstein wrong, etc.), you may be more likely to receive a response if you establish a username and say more about yourself. -Walter Siegmund 16:15, 31 October 2005 (UTC)

Why don't you post a query now? Dominick ^(ŤαĿĶ) 16:05, 31 October 2005 (UTC)

If you really are pursuing a PhD in physics, try a faculty advisor. You can also try posting the questions here. StuRat 16:40, 31 October 2005 (UTC)

I happen to be a physicist, and I check this page and answer questions regularly. Since I'm only pursuing my Ph.D. in this field myself, if you manage to really stump me I can ask my advisor, a noted physics scientist. So you've made your contact already, and you should post your questions! :) -- SCZenz 07:07, 1 November 2005 (UTC)

You could also solve the physics problem: What is the orbital proximity of Persons at State and National Universities, with PhDs. Start with a list of the 10 closest State Universities. Find their Faculty online. Check which ones have PhDs. ( I would recommend not contacting Professors Emitrius. ) Make a comprehensive list of the closest 25 Phds in Physics. Email them one by one for the most of a month. My College Physics professor said "If in order to make progress we must leave reality, by all means LETS LEAVE REALITY." -Stephen Brooks, Diablo Valley College, Pleasant Hill, CA. He had the red books, i.e. Richard Feynman's Lectures on Physics . Find a local library and spend a few weeks on reading the books. I am certainally glad I did, and I am impressed by the way that Wikipedia has presented both of these articles. You can also post your problems here, so that the last poster and I can quibble over the answers, and make them as clear and easy to understand as possible. Artoftransformation 08:58, 2 November 2005 (UTC). ( Note: after 4 minutes of viewing SCZenz page, I could just walk over to Southside and have a RootBeer with him. From his diagram of the Higgs boson...If we disagree, Id recommend you believe him. )

Charles Darwin and Edward Blyth?

Doing some reading on talkorigins.org led me to trueorigins.org and a few of their articles. There seems to be a creationist idea that Darwin nicked the idea of natural selection from Edward Blyth, who was a creationist. I ask because the Wikipedia article on Blyth (see above) mentions this. How legit is this? I hesitate to believe a darn word the creationists say, which is why I bring this up. grendel|khan 18:13, 31 October 2005 (UTC)

Darwin was certainly influenced by creationists like Blyth (here is a website that claims Blyth as a creationist). However, the challenge would be to point to a published article that existed before those of Darwin and Wallace that coherently expressed the idea of a fundamental role for natural selection in the origin of new species. Blyth wrote things like, "The original form of a species is unquestionably better adapted to its natural habits than any modification of that form." (see) Darwin was able to escape from this kind of thinking about species as fixed forms. --JWSchmidt 18:53, 31 October 2005 (UTC)

Darwin wans't quite the first to come up with the idea of evolution, he just wrote a book about it that really got the discussion going. Not surprising considering how obvious evolution is if you just look around and use your brain. Actually, Darwin's father was a Darwinist avant la lettre (which is of course a strang way of putting it because he was also called Darwin :) ). By the way, evolution doesn't preclude creationism. DirkvdM 10:34, 1 November 2005 (UTC)

I wonder exactly what you mean. You made a statement that was extremely arrogant and it simply doesn't make sense. You said that "evolution [is obvious] if you just look around and use your brain." which is very arrogant and foolish. The first is that you make it seem as if you looked around and discovered evolution. You didn't. You sat back and listened to a teacher tell you what you know and never thought twice about it. It probably didn't change your schema of the world drastically and was never even observed with great consideration. You say evolution is obvious. The answer is that it is obvious NOW. We now have the hindsight to see millions of tons of fossils and a large amount of documented speciation links through genetic populations across the world. We have large numbers of scientists who identify the most minute details of species and were able to find that speciation was more than just a hunch. These were serious scientific works and now you state arrogantly that "uh-duh! It is so simple!" but in fact, it took a great amount of proof across species. We have the good fortune to have verifiable proof through the works of Darwin to apply what we learned from the breeding of pigeons to the geographic isolation and subsequent changes in animals to large species, including ourselves. Humans had been breeding animals for as long as they domesticated them, and I'm sure you probably never even thought how those breeds were differentiated from their ancestors.

The reason I must focus on your statement is that there are too many people who use science, which is supposed to serve 'as a candle in the dark' or 'the absense of an ideology' and turn it into a dogmatic subject. That is the reason why creationism is striking itself in so many places. People simply don't understand evolution well enough to fend off the creationists or at least explain their knowledge. When that is coupled with arrogance, people fight creationism with great force but little reasoning. They simply say "use your brain" when they didn't and create a dichotomy of ideas, both of which are completely founded on faith, of which neither one has much scientific thinking behind it.

The reason why creationism (as we know it) originated is because after the Origin of Species, where Darwin really did his good work in explaining how species evolve, he went on to write the Descent of Man, which was not a very popular read for many people because it was founded on less solid evidence, less fossils, and finally, because it ashamed the human race to be known of as the descendants of monkeys. That sparked the controversy. The Origin of Species was subsequently looked at as a work of nonsense because it angered many to know that they were evolved from apes. The culture shock took time to come to grips with, but evolution is the more prevalent theory now. The other reason why evolution of humans was solidified was because scientists got more fossil evidence, so people "used their brains", went out there and proved it. I doubt you did any of that. The main reason why creationism is going up now in American classrooms is because the theory is not being taught well enough and people do not think twice about their positions. If people "used their brains" they would use proof and not just accept things, avoiding the whole "debate" (which is purely political, not scientific).

Don't accept things as "obvious". Use your brain.--Screwball23 ^talk 15:57, 2 November 2005 (UTC)

This is a spinoff from the main thread. Below is an earlier entry of mine in which I stated that I used the term creationism when I really meant creation (so "evolution doesn't preclude creation"). Also, I said Darwin's father was a Darwinist, which is also wrong. I just said it because it sounded funny. Sorry about that. What I meant is that he was aware of the notion of evolution. And many with and before him, which was my point. The reason for that was not all the fossils which were largely (though not quite exclusively!) found at a later time or the later detailed theorising. I simply meant the basic idea of evolution which is obvious when you think about it. I said something like the following before in another thread a little while ago.

Offspring are like their parents but not exactly the same That's it. That's all the info you need. The rest is thought. Well, you still need to have some notion of reality, namely that 'fitter' individuals (the ones that fit in better with their environment) will have a better chance of surviving, being fit and having offspring. But in the case of, say, deer, that is made so obvious (in the males) that the notion can't escape you. Actually, given how people these days are less in contact with nature might actually be a cause for people losing understanding of evolution. Anyway, the best adapted individuals will survive and pass on their 'good' qualities. Combine that with the variation and you get evolution. It's so obvious (indeed, once you've thought about it) that I find it hard to explain. But especially farmers will have understood. They used breeding, which is basically controlled evolution.

But to realise this you have to stop and think, which is what my remark about 'using your brain' was about. But that could easily be taken the wrong way, as you apparently did. Then again, I meant that in history many people must have stopped and thought an realised this. Which is also what I meant. Of course there are more complex issues, such as species counteradapting to each other – if cohabiting species change they change each other's environment, so the others have to adapt to that, etc. But the basic principle of evolution is extremely simple. Once you've thought about it. And many must have done so in the history of mankind. I wonder when the first such thoughts sprang to people's minds. Was it a result of breeding cattle and such (even hunting dogs?) or was that developed from an understanding of evolution?

You say that creationism is on the rise in the US because evolution is not taught well enough. Then maybe that should be done first by stripping it from its complication, like I tried to do above (not too well, though, I'm afraid). Simply ask kids the question how breeding works. Inspire them to think for themselves. Ask the right questions and they'll take it from there (well, some anyway). By the way, we're not descendants of apes (which misinformed teacher taght you that :) ). We are apes. DirkvdM 08:17, 3 November 2005 (UTC)

A little comparison to illustrate the above. The basic principle of evolution is much simpler than, say, that of gravity. That two objects attract each other is not obvious at all (and when it is obvious they do, it's for a different reason, like magnetism). So it took a long time for that notion to get thought through (still, well before Darwin, though). And even the less obvious notion that the Earth is round was already discovered by the Greeks. But for that you have to live by the sea to see its curvature and have some understanding about the qualaites of water. So, come to think of it, didn't the Greeks have a theory of evolution. Surely there must have been some ancient Greek who came up with the notion of evolution. DirkvdM 08:37, 3 November 2005 (UTC)

I disagree with that as well. The ancient Greeks were not largely evolutionists either. At that time, creationism seemed to make more sense because they hadn't been looking at a large array of species with the detailed and interested view of scientists looking for how change happens over time. In fact, evolution in general would be much harder to prove than gravity. Gravity, which is the force of attraction between two bodies that exists between all things was easy to think of when the planets were further identified and their respective orbits were seen circling larger bodies. The idea that "some ancient Greek [surely must have came up with the notion]" is giving a large amount of credit to individuals in society. There aren't a great number of free-thinkers out there who can think of one single difficult theory like that alone on an isolated Greek island. In fact, the accumulation of knowledge about evolution happened largely because of the growth of fossilized remains. Similarly, evolution requires great proof. There is debate in the scientific community as to what constitutes a species, but scientists have been able to isolate populations of a certain species and let them breed separately, and when the two were reunited, they usually chose not to mate with each other. This is still not solid proof of evolution because they are not really "species" much like there are anthropologists who debate race among humans.

To expand further on the idea that children aren't being taught evolution well enough, many evolutionists are very happy to announce that a belief in evolution increases with greater education, meaning that children need to think it out for themselves over time and often do come to the thought of evolution. However, they had to be taught this very well over a long time. Many had to rethink their faiths and their schema of the world greatly. You make it sound very simple because you probably never had to. You were taught one pattern and one idea about your origins and your life and never had to "use your brain" to really think it out. Breeding and genetic variation are very good examples, but in order to say definitively evolution does exist required a lot more evidence and solid facts than you give credit for. You continually compare yourself to a higher individual or a free-thinker much like that Greek you made up, but in fact, you must remember, you didn't discover evolution. You had the evidence and the knowledge accumulated for you and you had to use that to learn the truth. I largely doubt your sure-fire thought that evolution is "obvious". The same goes for your approach to teaching it to children. You say, tell them to see it for themselves. You can't say you saw evolution. You can't just say "believe it like I did" right away and say "it is extremely obvious". Another thing of interest is the immediate separation you make, almost like religious denominations. "well, some [will take it] anyway". That means you want some to just believe something because you say so and would separate yourself from the others, telling them to "go look and you can see evolution", practically ignoring any criticism of your ideology. That isn't science. A scientist would defend his theories. To say "some will learn it, the rest will have to go look for it" is not scientific or educational. That is dogmatic in a sense. Again, don't take what you know of in such an arrogant form. The ideas of evolution are the result of an "evolution" of theories and evidence that eventually led to more concrete knowledge. It isn't a process you can go out and demonstrate to the class. It is indeed not obvious, but more of a learned and complicated branch of knowledge. It is among the fundamentals of science, crucial to our understanding of living things, but is not very "basic". Even the basic models have experienced scientific thought--gradualism, punctuated equilibrium, and genetic variation--all added and combined to make the theory bigger and better, so it wasn't an unmoving and stable idea that you can "see for yourself". Don't confuse science with dogma and don't think the education system is doing such an adequate job if we can see great confusion among school districts across the country.--Screwball23 ^talk 17:17, 3 November 2005 (UTC)

While the Theory of Evolution, and science in general, don't eliminate the possibility of creationism, say in the form that "God created the big bang", they do eliminate the version of creationism listed in the Bible, Torah, Koran, etc.

In short, when creationism is sufficiently vague, it can't be tested and refuted. However, when it is specific enough to be verified, it can be disproven. For example, accounts of the creation of the Earth being several thousand years ago can be disproven in many, many ways. Those include radioactive decay, continental drift, magnetic reversals, biodiversity levels, etc. StuRat 17:04, 1 November 2005 (UTC)

I'm sorry, I used the wrong term, I meant 'creation'. 'Creationism' is much more specific. Btw, all your arguments can be wiped off the table with the argument that God created those illusions to test our faith :) . That is, all but the first. DirkvdM 09:37, 2 November 2005 (UTC)

That is very true. A belief that evolution was put there to "tempt mankind" into secular humanism would ruin the relationship between science and religion entirely. That would make all we know of through evolutionary science a type of pseudo-science because of a greater master plan. Unfortunately, this view is directly connected to religion and would encompass presumptions for which there are no experiments. That would only disprove macroevolution (the evolution of different higher species) but wouldn't stop microevolution, which can be proven very well now. That would be a very slippery ideology and would accomplish all that creationists are angry about--the descent of man from ape-like ancestors. Such a view is assuming a different nature to the Divine One and is a simple dismissal of all that evolutionary science and anthropology has taught us. It's an interesting idea.--Screwball23 ^talk 19:23, 2 November 2005 (UTC)

• After the reception of Origin of Species, a handful of "heirs" came out of the woodwork to claim priority. There is little evidence that Darwin took anything substantial from them -- his main influences, both in the genesis, formation, and articulation of his theory, came from sources which he cited excessively. I don't know the details of the Blyth question in particular, but the fact that the main link given to support the line in the article is from an anti-Darwinian Creationist article, I removed it as being fairly POV. If it is something of relevant historical consequence it should not be hard to find a legitimate source. In any event, it would be worth noting that Darwin's theory was one about speciation -- the emergence and differentiation of species of animals, not just that sick animals die off more than healthy ones. --Fastfission 03:28, 3 November 2005 (UTC)

BIODIESAL FUEL MANUFACTURING

I have a high interest in both the environmental and financial benefits of converting used cooking oils into biodeisal. Problem is that I have no idea of where to begin in researching relative equipment, necessary chemicals for the procedure, and overall cost of initial set up. Also to consider is the different environmental laws to be met dependant upon the different states. Help!!! Chris --**--

I believe an experiment was done where two people drove cross-country using a conventional engine with only minor modifications and using cooking oil from restaurants as fuel. The only processing they performed was to filter the cooking oil. StuRat 20:13, 31 October 2005 (UTC)

That is known as using Straight Vegetable Oil. It's really not a good idea in an engine you value because in using SVO varnishes form that coat the engine. Biodiesel, which is processed vegetable or other oils, is expected to be free from those problems. To the original asker, our biodiesel article gives the overview, but if you check through the links at the bottom, you'll find much of the best information available online for what is needed to make biodiesel. Particularly good websites include http://www.biodieselcommunity.org/ http://www.journeytoforever.org/biodiesel.html and the forums at http://www.biodieselnow.com/ for questions. Also read our articles Biodiesel production and Biodiesel recipe for more detailed overview of making the stuff. Some of those links include detailed tutorials on how to make your own homebrew. This article is one of the article's references, and contains a lot of detailed information on the numbers behind setting up a biodiesel production plant. - Taxman ^Talk 23:15, 31 October 2005 (UTC)

The articles on biodiesel give a good starting point, and, depending where you live, there are probably associations not too far from you that do this. Where do you live? Trollderella 22:44, 31 October 2005 (UTC)

Given that he refers to state laws but doesn't mention the country, my guess is the USA. DirkvdM 10:38, 1 November 2005 (UTC)

Yes; that is correct. I am in the states, but more exact, I'm Military (Air Force) at Andrews AFB. So a concern on environmental laws would cover Maryland, Virginia, Delaware ... Been in 20+ years, so who knows where/what governing EPA laws I'll have to be concerned about next. Gotta say though, initially saw an overveiw of how Biodiesal is made on Dish Network "Dirtiest Jobs". Never dreamed there was a website like this, and I want to Thank You All very much for the information. MSgt Christopher Dow

The Australian rat, the most sexually active animal

Im doing a research on the most sexually active animals on the face of the earth. It has come to my attention that a certain wild rat in Australia is the MOST sexually active as during the mating season, the male rat goes on a mating rampage where it does not stop to eat or drink but goes on mating for weeks until it dies of hunger and dehydration. may i know the nam of this particular rat? thank you very much.

Mel Gibson ? StuRat 22:56, 31 October 2005 (UTC)

There is show on TV in Australia tonight, Sex in the Bush, that deals with this (on the ABC). Its promo includes the text "Male marsupial mice literally copulate themselves to death". I don't know if this is a coicidence (ie: you have seen this promo), but I'll watch the show anyway and try to get the exact name of this mouse. --Commander Keane 08:51, 1 November 2005 (UTC)

LOL, nice one StuRat. :-) Akamad 10:54, 1 November 2005 (UTC)

The mouse was on Wikipedia all along: Antechinus. Indeed, the article mentions its "sex-crazed rampage". It was mentioned on that show I watched.--Commander Keane 12:41, 1 November 2005 (UTC)

"The mouse was on Wikipedia all along"? was that the symptom of it being sex-starved or the causation? Johntex\^talk 19:41, 3 November 2005 (UTC)

I think that's a question we all ask ourselves at some point... {{subst:User:Omegatron/sig}} 20:19, 3 November 2005 (UTC)