Wikipedia:Reference desk/Archives/Science/2006 November 16

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November 16

electric bike

I am working on a project to build an electric bike similar to the one being sold by Golden Motors (China)that uses a brushless DC motor/generator inside a front wheel hub. It costs $175 plus about $60 for shipping to where I live but I think I can do a better job for less money and learn alot about motors and generators along the way in addition to having a lot of fun. Any design or construction tips or suggestions about where to buy magnets etc.? 71.100.6.152 01:50, 16 November 2006 (UTC)

That kit is remarkably cheap, in my view. I very much doubt that you'll be able to build something cheaper. Better, perhaps, but not cheaper. Regardless, I'm almost certain you won't be able to build an electric motor that's competitive with factory-built ones. -Robert Merkel 05:01, 16 November 2006 (UTC)

Mother Earth News had plans in the 1970's for electrifying a bicycle with a 12 volt starter motor from a car. The kit price sounds reasonable. Edison 05:42, 16 November 2006 (UTC)

Yes, very reasonable but it won't help me learn anything about building various types of practical DC brushless motors unless I try to take it apart. 71.100.6.152 11:02, 16 November 2006 (UTC)

I liked looking at the products, and we actually have something on this: Brushless DC electric motor, which is a very interesting read. Looks like China has an advantage here, since these motors must be hand-wound, and use custom circuit boards. It would be difficult to do it yourself, but you could take apart hard-drive and fan motors to see how they work. People are doing this for electric model airplanes. --Zeizmic 13:52, 16 November 2006 (UTC)

Yes I've taken a broken fan motor apart to see how it worked and read about modelers using 58x CD drive motors in model airplanes. In fact after one shattered a CD and busted the drive I thought about using it for something like that myself but I wanted something with enough power to get me up a hill on a bike (which is hard sometimes with a ull load of groceries) as well as using it to charge the battery coming down hill as well as break the decent. I don't theink the motor from China is going to have the power I want. All I really need are coils, magnets, Hall effect switch and a battery right? 71.100.6.152 15:46, 16 November 2006 (UTC)

energy

what criteria must be met before energy can be conserved?

First sentence of Conservation of energy? --Wirbelwindヴィルヴェルヴィント (talk) 02:11, 16 November 2006 (UTC)

But maybe you're talking about energy conservation ? StuRat 06:56, 16 November 2006 (UTC)

Conservation laws arise from continuous symmetries. Specifically, energy is conserved if physical laws are invariant with respect to translation in time. See Noether's theorem. Gandalf61 11:54, 16 November 2006 (UTC)

The big rip, explained for a layman?

Recently someone posted a link to the big rip in a discussion about the universe. I have to say I didn't really understand that article, especially this sentence: "...this implies that the size of the observable universe is continually shrinking; the distance to the edge of the observable universe which is moving away at the speed of light from any point gets ever closer. When the size of the observable universe is smaller than any particular structure, then no interaction between the furthest parts of the structure can occur" If the edge of the universe is moving away (from us?) at the speed of light, how can it "get ever closer" ? As best I understand it, while the physical objects like stars and galaxies are, in fact, moving away from each other in the macroscopic universe; per the Big Rip theory whatever invisible stuff makes up the fabric of the universe is shrinking, and so while that shrinking can't be perceived or measured (?) in the macroscopic universe, at a quantum level it is still affecting the macroscopic universe. Is that correct? What is that "stuff" that is shrinking, anyway, and how does it relate to other theories of matter and existence, like string theory? What would be some other articles to read? 192.168.1.1 6:59pm, 15 November 2006 (PST)

The key term there is "observable" - while the actual universe is getting bigger, the area that we can see is getting smaller. There is no "shrinking" in the classical sense, other than the amount of stuff we can see is shrinking. Another article that was not listed under the See also section would be cosmic inflation, though that might be a bit difficult to read. Virog^{It's not}_{my fault!} 03:08, 16 November 2006 (UTC)

It's good to know we've got about 20 billion years before the end of time. --Cody.Pope 05:12, 16 November 2006 (UTC)

It is confusingly phrased and should probably be corrected. Here is my explanation: If you have climbed a tower, the horizon is far away; then as you go down the horizon gets closer and closer. This movement of the horizon is not a real movement, and the horizon is not real but only a virtual thing. The edge of the observable universe is like a horizon, it is also virtual. To someone who is (with respect to us) at that edge, there is nothing remarkable there. But we are at the edge of her observable universe. This edge is very similar to the event horizon of a black hole. In fact, you might say we are living in the non-black part of a black hole turned inside out (just like haggis is a sheep turned inside out). Everything beyond the edge is black: nothing, not even light, can escape from there to us. While space rushes out, the blackness moves in. The edge is where space rushes out at the speed of light.  --Lambiam^Talk 08:29, 16 November 2006 (UTC)

induction heaters

I was surprised to find that there are three types of induction heaters. One appears to use a coil with high frequency (20khz) alternating current flowing through it to heat a "core" of magnetic material placed inside the coil and the second appears to heat non-magnetic but electrical conductive materical that has been formed into a closed single turn secondary coil around a closed core with a primary coil and the third is magnetic material inserted between the ends of an open core. Can anyone tell me how each of these induction based heaters work, if there any other types of induction heaters and if is there a working circuit diagram for each type of coil anywhere? I've only found a few homemade coils on You Tube and other places but no circuit diagrams or details of how they work. 71.100.6.152 11:33, 16 November 2006 (UTC)

Have you already read our Induction heating article? (I know it's a bit sparse.) What points do you need more info on?

Atlant 18:00, 16 November 2006 (UTC)

Well a complete circuit diagram and parts list would be nice for one homemade unit I've seen at You Tube. 71.100.6.152 23:23, 16 November 2006 (UTC)

PLC

hi,can you please give me some information about different methods of communication in a programmable logic controller with an input device such as computers i am sepecifically after some information with the use of following devices →twisted cable →co-axial →fibre optics please reply me with the use of these devices in PLCs including there advantages and disadvantages olus their use in industry.

Essentially, the various physical layers and communications protocols just provide varying trade-offs between cost, distance, speed, reliability, configurability, and the like. Roughly speaking, ranked in order of increasing cost, you might find:

1. Twisted pair (whether point-to-point or multidrop)
2. Coaxial cable (point-to-point or multidrop)
3. Fiber optics (always point-to-point)

A PLC easily generates twisted-pair, coax, and light-emitting diode-driven-fiber protocols. It'll cost you some serious money to generate long-haul, laser drive fiber protocols.

After reading all that (and the referenced articles), do you have a more-specific question?

Atlant 18:06, 16 November 2006 (UTC)

RPM

How many rpms would a fan blade have to spin at to generate wavelengths of visible light? And is it possible, or would ho-hum-trillion rpms be too much for any physical structure to tolerate?--172.134.127.134 15:47, 16 November 2006 (UTC)

(My area is way lower frequency phenomena, but I will have a go at it. Those skilled at fields and waves please correct any misstatements.) First determine why a spinning fan blade would generate electromagnetic waves at any frequency. Do they have magnets attached?(careful, they will fly off when you least expect it). Or are the blades electrically charged? If it had 2 blades with opposite electric charge on them or opposite magnetic polarity, it would be a rotating dipole. It would generate an alternating field as it rotated. The wavelength is so short that the rotating fan blade could be submicroscopic and still be an efficient radiator. Electromagnetic spectrum says the longest wavelength (lowest frequency) of visible light is 700 nm (red, right next to infrared in wavelength). To get frequency, divide the speed of light by the wavelength: frequency=c/wavelength = (3*10^8 m/s)/(700*10^-9 m)=4.28 *10^14 Hz. Multiply by 60 to get revolutions per minute: 2.57 * 10^16 rpm, or 25,700,000,000,000,000 rpm. It would have to be down at the atomic or molecular level to not fly apart from the radial forces. The article Micropower tells how researchers are actually fabricating tiny high speed turbines and generators out of etched silicon wafers, using technology derived from integrated circuit construction. They have built a generator 10 mm wide which spins at 100,000 rpm, with higher speeds in the works, but this is many orders of magnitude larger and slower than what your fan based optical generator would require. Edison 17:21, 16 November 2006 (UTC)

If f is the frequency and r the length of a blade (the radius of the fan), the tip moves at a speed v = 2πfr. Since v < c, r < c/(2πf). Using f = c/λ (see Edison's reply), this means r < λ/(2π) ≤ 700/6.28 nm = 111 nm. This is truly a nano engine.  --Lambiam^Talk 18:37, 16 November 2006 (UTC)

<joke>The fan will be generating visible light far earlier than that, when its motor catches on fire at such a high RPM. </joke> 22:39, 16 November 2006 (UTC)

Eyeglass prescription

Is the following idea obsessive-compulsive or is it sound? I can't tell.

I have a new prescription for my very first pair of eyeglasses:

		Sphere	Cylinder	Axis
Distance Vision	oculus dexter	+0.25	-0.75	180
	oculus sinister	-0.25	-1.00	010

They say you should renew the prescription every 2 years, and my insurance only pays up to $340 CAD once every 2 years, so basically I will be wearing these for quite a while. So I want to make sure they are 100% physically accurate to my eyeball needs.

As such, I am very tempted to go to a totally different optometrist and actually pay the money for a 2nd prescription, just to compare with the first one and "make sure" it's 100% accurate. Theoretically the two prescriptions would be exactly the same, although something tells me they probably wouldn't be.

Any thoughts or knowledge on this matter? --Sonjaaa 16:05, 16 November 2006 (UTC)

Yes - from personal experience - once your eyesight settles down (mine got worse up to the age of about 16 and hasn't changed much since then - might be something to do with puberty and adult head shape?) the prescription won't change much - on repeated eyesight tests (at the same and different opticians over 5 years)I got roughly the same every time - but it does differ from time to time - by a very small amount - I assumed this was due to experimental error - and the human body is not a rigid thing - so mabye the perfect presciption varies from day to day. More noticably I noticed a very big difference with lenses made to the same prescription from different manufacturers. In the UK the eyetest is cheap but the glasses are expensive so it's not a big problem to get your eyes tested again. —The preceding unsigned comment was added by 87.102.1.174 (talk • contribs) 18:51, November 16, 2006 (UTC).

(insert usual disclaimer about this not being medical advice... if you die because of what I wrote, you can't sue me from the grave, etc etc...)

As someone who has been wearing glasses since the age of six, I can tell you that "accurate prescription" is very loosely defined. Your eyes work better and worse in different circumstances, you'll find that you see worse when you're tired, at the end of a long day, if you've spent a long time in front of a screen, in bad lighting conditions (dusk, especially), etc. So there is no one "true" prescription for you.

Second, the major cost in changing prescriptions is the frame, not the lens (at least, that's been my experience in Europe, although I imagine in holds true in Canada as well). So once you get a frame, you can change the lenses without having to buy a new frame. So even if you feel your first prescription is 'off', you can always try it out for awhile before deciding whether you want to change it. Do make sure to enquire as to the cost of frame+lenses or just lenses at your optician's before going down this road. Note that there are several different kinds of lenses (plastic, glass, coated plastic...), your optician will explain the differences, advantags and disadvantages to you.

With a weak prescription like yours (1 diopter is nothing!), your eyesight is still very good, and the difference that + or - 0.25 or 0.5 in either direction will do is minimal, you will barely notice it. I don't think it's worth getting fussed up about, especially taking into consideration the variability of your eyesight (as mentioned above).

There is the added factor that, for a given eye, there is a choice to slightly (usually by + or - 0.25) over- or under-correct your sight. This is a decision best left to your eye doctor, I know nothing of the subject, but different methodologies used by different doctors may account for a discrepancy in different prescriptions given by them (in addition to the natural variability). Next time you may wish to talk to your doctor about this, and try out different lens strengths slightly above and below what (s)he recommended, to see what the effects are.

So, in conclusion, my advice to you is: go with that prescription, and live with it for a few months. See how you feel using your glasses - do you find yourself squinting a lot, do your eyes feel very tired after long stretches of different activities (eg computer use)? If you drive or cycle (or similar), can you read the roadsigns far enough ahead (this one is usually a good test of your eyesight) for you to feel safe? Most of all, though, do you feel comfortable with your eyesight? Take all this feedback back to your doctor next time you see him/her and discuss it. But, to be honest, with your eyes (my glasses are around -6.0, I'm blind as a mole without them!) there isn't much that can go wrong.

Hope this helps! — QuantumEleven 16:46, 16 November 2006 (UTC)

With the above disclaimers: I am not an eye doctor, but I have worn glasses for many years and I once slept in a Holiday Inn Express (reference to U.S. tv commercial). The sphere correction is minimal, but you have a stronger cylinder prescription to correct astigmatism. Without the glasses if you look at a vertical line and a horizontal line, you will likely notice one of them appears better focussed than the other. With the corrective lenses, they should both appear sharp. But you may find it takes a few days to get used to corrected vision; your brain is accustomed to the size distortion in the vertical versus the horizontal direction, so when you step off the curb (kerb?) and look down, there may be a moment of disorientation. Edison 17:31, 16 November 2006 (UTC)

Optometrists also "balance" your prescription needs between good near-focus and good far-focus. I discovered this when I complained to my optometrist that the correction I'd gotten from his last several sets of glasses wasn't very good. He then gave me a prescription that was purely aimed at correcting my distance vision (and damn my ability to use it for near vision) and the correction was remarkably better, but of course I have to take the glasses off a lot more to work up close. So be sure to tell your optometrist what your specific goals are.

And yes, they sometimes get it blatantly wrong or you gave a conflicting set of "better"/"worse" answers. This happened to me at least once.

Atlant 18:13, 16 November 2006 (UTC)

I went for a second opinion and got these results:

New Prescription		Sphere	Cylinder	Axis
Distance Vision	oculus dexter	+0.50	-0.75	180
	oculus sinister	+0.50	-0.75	015

The sphere for left eye is quite different!! --Sonjaaa 22:23, 16 November 2006 (UTC)

• Whenever I have my eyes checked, they ask me a series of questions about which lense views more comfortable. Part of the difference probably lies in your own input in the testing. Also, I wonder if both optometrists measured in the same way. Did they both test each eye separately and did a control to see if it would work with both eyes together afterwards? Did they test the pressure in your eyeball by blowing air into it? When you look into the distance with one eye. Do you see any discernable difference between left and right? Eyes tend to tire throughout the day, did you take both tests at approximately the same time in the day? Did you do something like watching a monitor or movie screen shortly before. I have worked at an store where I sold glasses and did basic measurements, but remember I can't give proper medical advice over the internet. By the way, eye tests can be done for free in the Netherlands if you don't suffer some serious eye illness (it saves a lot of waiting with a specialized eye doctor). If you want a third opinion, try a college/university that offers an optometrist's program. The students might need a patient for some classes. It might get you a free measurement. - Mgm|^(talk) 10:25, 17 November 2006 (UTC)

Call me paranoid, but I think that the optometric community is involved in a conspiracy to get everyone on glasses. Think about it:

• The conditions of the exam room - dark, difficult to see, designed for eye strain.
• Progressively stronger prescriptions weaken your eyes further; this causes increasing dependence on eyeglasses.
• Overprescription; have you noticed that new glasses seem excessively strong when you try them on for the first time?

My eye doctor screwed me; He prescribed glasses for 20/30 vision, and my vision has deteriorated since. Asshole. -- Sturgeonman 19:23, 19 November 2006 (UTC)

• Funny how people always see conspiracies. About one of your comments: "Overprescription; have you noticed that new glasses seem excessively strong when you try them on for the first time?" There's a perfectly logical explanation for this effect. Your eyes need to get used to wearing the glasses, because before they strained to see properly. If you do that when you put on those glasses it will feel like you're overcorrected, but that's due to your own eyes, not the glasses. Also, once your vision requires correction, it usually deteriorates, because your eye is not 100% healthy. If you want to get rid of eye doctors or glasses. Try getting laser surgery or practice those eye training exercises that claim to stop deterioration. I haven't tried those, but it can't hurt to try. - Mgm|^(talk) 12:54, 20 November 2006 (UTC)

Acarids

How come I can't find any information on acarids , acaridans on Wikipedia? Is it because they have another name? Keria 16:29, 16 November 2006 (UTC)

Is this it? Acarina If so, then somebody should create redirects to help ppl find it more easily. --Sonjaaa 16:38, 16 November 2006 (UTC)

Thank you very much - my dictionary gave me acarid as translation but it doesn't seem to be the usual term. Keria 16:41, 16 November 2006 (UTC)

It might not be the most common term, but it's not an unreasonable term to expect to work (many dictionaries, including wiktionary, have one or both names). So acarid, acarids, acaridan, and acaridans are now all redirects to Acarina. -- Finlay McWalter | Talk 19:01, 16 November 2006 (UTC)

Prothrombin time

Most articles trace the first description of the prothrombin time, discovered by Dr Armand Quick of Milwaukee, to a 1935 paper in J Biol Chem. I recently discovered that this reference does not in fact exist (as JBC is now available fulltext for free back to 1905). How could this have happened? JFW | T@lk 16:33, 16 November 2006 (UTC)

There certainly seems to be many references to that article, but there is another one of the same time with a similar title
Quick AJ, Stanley-Brown M, Bancroft FW. A study of the coagulation defect in hemophilia and in jaundice. Am J Med Sc 1935;190:501
It is odd that two nearly identical articles (at least judging by their titles) would be published the same year in two different journals.--Mabris 16:59, 16 November 2006 (UTC)

I suspect that it was a simple mistake (somebody knew they had read the article, but got the name of the journal wrong). However, since the journal was not available for free for people to verify this ref, they just took it on faith and replicated the error. This is a problem with sources that aren't readily available for free. Wikipedia should try to keep uses of such refs to a minimum, because of just this problem. StuRat 19:02, 16 November 2006 (UTC)

I am shocked, SHOCKED I say, that generations of scientists would cite a paper without having actually read it. Edison 22:56, 16 November 2006 (UTC)

Err cough cough. How long exactly have you been a scientist? 8-)--Light current 02:30, 17 November 2006 (UTC)

I once went to the library of a major research university to look up a much-cited paper in a journal from 1905. In the binding process, the edges of the pages of the issue were not slit apart. It had never been opened. Perhaps it was read via the Sleep learning method [1] of Edgar Cayce all the times it had been cited by scientists at the school.Edison 03:51, 17 November 2006 (UTC)

Future geography

I've seen maps of the Earth's original landmass, Pangaea, and its evolution as plate tectonics cause it to morph into the continents of the present day. Have geologists predicted what the Earth is going to look like in another several million years? Maps, predictions, or other opinions would be greatly appreciated. --Naferius 17:31, 16 November 2006 (UTC)

At Continental drift there is a link [2] which shows the continents, past and future. Edison 17:34, 16 November 2006 (UTC)

However, note that Pangaea is not the original land mass, as the supercontinent cycle has repeated itself many times over the Earth's history, causing various continents to join, then break apart again. We can trace back through the last several cycles. StuRat 18:47, 16 November 2006 (UTC)

Since the continents are destined to jam together again, and maybe break apart at different places, we can only go so many (hundred) million years in the future. --Zeizmic 21:38, 16 November 2006 (UTC)

To put this in perspective, the oldest map on that site is from 650 million years ago. So it only covers about 15% of Earth's history. Does this mean that nothing is known about the location of landmasses before that (only that they existed)? DirkvdM 09:12, 17 November 2006 (UTC)

The farther back we go, the fuzzier the info gets, yes. StuRat 09:53, 17 November 2006 (UTC)

The link is great - I wonder how the plates cause the continents to start in the southern hemisphere, and drift to the position where they are now, with the majority of landmass, ignoring Antartica, being visibly in the northern hemisphere.

The driving force is convection cells, where the core of the Earth cools itself by causing the mantle to "boil". The continents then move on these cells, similar to how scum on the top of a pot of boiling milk moves around. StuRat 20:27, 17 November 2006 (UTC)

And we're the scum that lives on top of that scum. DirkvdM 06:41, 18 November 2006 (UTC)

Makes me feel so desired in this universe. --Naferius 14:59, 18 November 2006 (UTC)

Diabeties

Can people get diabeties from eating meals too far apart? For example having breakfast at the normal time but then not eating until late afternoon?

--213.106.15.82 19:23, 16 November 2006 (UTC)

I don't think that could cause diabetes, but could make the symptoms worse if you are diabetic or pre-diabetic/hypoglycemic. A large number of small meals is typically recommended for such people, to keep their blood sugar as constant as possible. StuRat 19:38, 16 November 2006 (UTC)

No. No. alteripse 21:11, 16 November 2006 (UTC)

I have never heard of a direct causal mechanism for diabetes being meal timing. There may be some indirect effect wherein meal timing gives rise to greater caloric intake, thus it leads to weight gain and precipitates the onset of type II diabetes. So maybe, in an indirect way, but I can't think of a direct pathway. --TeaDrinker 21:38, 16 November 2006 (UTC)

for psychiatrists

What happens if a person who doesn't have any psychotic dissorder like schizophrenia starts taking neuroleptics and antipsychotics? does that person have a risk of actually developing schizophrenia if without taking that medicine that person was not destined to have the illnes develop ever at all?.

do other psychiatric medicines like antidepresants and axiety/epileptia pills like rivotril also have the posibility of triggering schizophrenia or any other dissorder like bipolar dissorder or multiple personality or whatever?.--Cosmic girl 22:27, 17 November 2006 (UTC) (sorry I forgot to sign it).

Miscellaneous side effects without beneficial effect. No. No. alteripse 21:10, 16 November 2006 (UTC)

I don't believe antipsychotics will cause a disorder like schizophrenia in a normal person, but it is definitely not considered safe for a person without a disorder to take any drugs which alter brain chemistry, especially long term. Taking medication or recreational drugs which create imbalances in brain chemistry (seratonin, dopamine)may make changes which are irreversible. This is a field which is still activley being researched. Vespine 22:10, 16 November 2006 (UTC)

If you read carefully the patient leaflets on these mind altering drugs, you will see that some of the side effects they can cause are actually the same as the condition for which they have been prescribed! THis also applies to some other types of drugs in my experience.--Light current 23:20, 16 November 2006 (UTC)

As a chemist (not psychiatrist) the answer is yes (or they may cause another mental illness that would not develope without the drug use.) The effects may or may not be permanent. Other possible side effects are mental retardation (for the period of use) and unknown long term effects - the only way to find out is try it.

As to the second question - antidepressant use can cause depression. You mentioned rivotril - I don't know much about this personally but the rivotril article states it is a benzodiazepine derivative - you could read that article for some clues..

Sorry, I disagree with some of the above answers, or at least the opinions need some support. Can anyone cite any evidence that antipsychotics can cause schizophrenia in someone not predisposed? I didnt think so. And I suspect the anonymous chemist is confusing tardive dyskinesia with mental retardation. alteripse 02:41, 17 November 2006 (UTC)

Antipsychotics can cause psychosis it seems - I didn't specifically mean schizophrenia - psychology is a strange subject if you ask me - explaining a predisposition to an illness or lack of it seems complex. Tardive dyskinesia may be all you see when observing someone on certain antipsychotics but I would suggest that the 'lights have been turned off' or at least dimmed as well. Please take me on my word that these drugs are not something you should give to people.

so psychiatrists are assholes?.--Cosmic girl 22:31, 17 November 2006 (UTC)

Not according to me.. Prescribing poisonous drugs is the bit I object to... Most psychoactive substances are poisonous - if you think about it - that includes medical drugs as well as recreational drugs. I'm not in a position to attempt to take the moral high ground here.

In my experience (one psychiatrist i met) - they were not keen to have to prescribe drugs - and who would be.. Remember one of Confucius's sayings "the best doctors have no patients" - in some way prescribing a drug means failure.

This is Tom Cruise-type nonsense masquerading as answers. All drugs are "poison" at some dose. No doctor or reasonable person thinks taking an antipsychotic could have no bad effects. You haven't offered evidence against either of my points: (1) antipsychotics can produce unwanted effects ("side effects") for anyone who takes them but (2) have not been shown to cause either schizophrenia or mental retardation in anyone. I will add a third: (3) they are no more dangerous to people without schizophrenia than with schizophrenia, but there is simply no potential beneficial effect to make the unwanted effects worthwhile. alteripse 01:40, 18 November 2006 (UTC)

thanks - no idea what 'tom cruise type nonsense' is but it sounds bad. My point is that these drugs are poison at any dose. Haloperidol " Depression, severe enough to result in suicide, is quite often seen during long-term treatment" Phenothiazine - "tardive dyskinesia and sedation" - sounds to me when in combination like mental retardation. Read the side effects section in a wikipedia article of any drug used for mental disorders and then try to prove to yourself it's not a poison. Your third point is a good one but 'no more dangerous' is not good enough for most people. Not dangerous would be acceptable. Somebody asked about anxiety drugs "triggering schizophrenia or any other dissorder like bipolar dissorder or multiple personality or whatever" - in the worst case withdrawal from benzodiazepine can trigger psychosis - can you distinguish between schizophrenia and psychosis? (rhetorical question). Apologies for winding you up.

OK, I am unwound. Schizophrenia and psychosis are disabling problems that can prevent a person from holding a job, maintaining a place in the community, or maintaning relationships with the people important to them. Antipsychotics can help some of the people with these problems to hold jobs and maintain relationships. It is demeaning and insulting to people with mental illness when people with no experience, no stake, or little knowledge pass judgement on what treatments should be allowed or the motives of those who are trying to help, but offering little more than "think positive" or "snap out of it". Lots of drugs used for many conditions cause side effects, but they are often the least bad choice available for bad problems. alteripse 04:41, 18 November 2006 (UTC)

(I'm no MD) If you read the list of side effects and cautions for specific medications, classes of medications, or types of medications (like [[3]], you'll see that antidepressants can cause hypomania or mania (the opposites of depression), as well as numerous other side effects. Neuroleptics/antipsychotics can cause, among other things, akathisia and/or dysphoria. While they may not cause the illnesses you are asking about, they can cause many of the symptoms of those illnesses. --Ronz 05:26, 20 November 2006 (UTC)

Meals for humans

Is the human body designed to require feeding 3 or 4 times a day. Or do we do it just to stop ourselves feeling hungry?--Light current 23:29, 16 November 2006 (UTC)

I do recall that we are supposed to eat about six "snack-like meals" a day instead of three big meals... Cbrown1023 00:15, 17 November 2006 (UTC)

It is recommended to eat little bits, more often, throughout the day, rather than a whole lot in just three meals. --Russoc4 00:24, 17 November 2006 (UTC)

From Human Evolution: "Early hominoids, like apes, were essentially plant eaters (fruit, leaves, roots), their diet only occasionally supplemented by meat (often from scavenging)." We evolved from chimpanzee-like animals that generally ate several times during the day, and this is thus the best way to feed ourselves today. Dar-Ape 00:33, 17 November 2006 (UTC)

And who could question the authority of an ape on this subject? :) DirkvdM 09:18, 17 November 2006 (UTC)

None of which answers the question. Try these versions:

1. Most of us do not think the human body was "designed". If so, we have no direct information from the Designer as to an intended eating frequency.
2. "OK, what eating frequency did most early humans have?" We don't know. Anthropologists can tell all the just-so stories you like, and you can compare us to any ape you like, but we simply do not know. About all we know is that humans are amazingly adaptable in terms of what we can eat and how often.
3. "All right, then what is the healthiest meal frequency?" We have no controlled trials demonstrating that one frequency is better than another. For a modern sedentary lifestyle in an urban environment with American food abundance, there is some evidence that eating more earlier in the day and less later in the day is healthier. alteripse 02:35, 17 November 2006 (UTC)

Bravo! Can you make a template out of this answer for every "what is the proper..." questions? --best, kevin [kzollman][talk] 06:12, 17 November 2006 (UTC)

Do you mean you think that Alteripses is an 'ideal' answer? Yes its pretty good as it answers fully the question asked and the question that should have been asked! Yeah Ill give it 8/10. --Light current 11:04, 17 November 2006 (UTC)

You mean a big breakfast, light lunch and modest dinner? (maybe with snacks in between? 8-))--Light current 02:38, 17 November 2006 (UTC)

Some Wise Man (Ben Franklin?) said "Eat breakfast like a King, lunch like a prince, and supper like a pauper." And most people who say "I never eat breakfast" in fact eat it about 11 pm.Edison 03:54, 17 November 2006 (UTC)

I always sort of compared my eating late at night with others eating breakfast (I don't eat "breakfast"). However, I do believe there's research saying several small meals is better than 3 big meals, but I don't know why people don't advocate it. It's better for the metabolism, weight, etc, so I know it's recommended to some people who are trying to lose weight. I always just followed what my body tells me, which is eating more often in a day, but not eating so much at each "meal", and I guess there's some biological studies backing that habit up. The 3 meals thing has to be invented by society. All the pets I've had (save one) also always had food out, and when you do that (considering they're not gluttons), they eat at random times in the day. I didn't realize that till just 5 minutes ago, but that could be some sort of proof that we're just supposed to eat when we're hungry and not so much during meals, which also cuts out the notion that you have to eat a lot at each meal to last till the next one etc. --Wirbelwindヴィルヴェルヴィント (talk) 09:23, 17 November 2006 (UTC)

So maybe you should just eat enough to satisfy the hunger pangs and not so much that your are stuffed full? 8-)--Light current 10:45, 17 November 2006 (UTC)

Different cultures eat on entirely different meal schedules. In the US we usually have a small breakfast, medium lunch, medium dinner; in Brazil, if I recall, you have a small breakfast, huge lunch, small dinner. The human body is remarkably resilient to adapt to different types of eating, which makes sense: in the wild, one does not always get to choose exactly when and how much one eats. If one were locked into a "eat one way or suffer horribly" sort of cycle one a civilization would not have the flexibility to do the sorts of things that humans have done (like migrate across arid lands). --24.147.86.187 13:45, 17 November 2006 (UTC)

Yes but it does appear the humans eat 3 or 4 times a day over the world. How did we get to that? Was it found by trial and error that if this pattern is followed, we do t get too hungry?--Light current 16:40, 17 November 2006 (UTC)

science fair project

what type of trees make money? where are the trees located? email removed

money is made of cotton... see Banknote#Materials_used_for_banknotes. Cbrown1023 00:14, 17 November 2006 (UTC)

"Money on trees" is just a cliche. Though I'm sure a lot of people wish it was true! --Wooty  Woot? | contribs 01:33, 17 November 2006 (UTC)

I'm guessing they are asking which types of trees are profitable to grow. There are fruit trees, and trees used for lumber, and others used for their sap (to make rubber or maple syrup). Some lightweight wood has special uses, like cork, balsa, and bamboo. Some tree leaves can be woven to make baskets. Particularly large, old, or unusual trees may make money by tourism. Other trees are only suitable as firewood. StuRat 02:33, 17 November 2006 (UTC)

Pulpwood for paper, nut trees... -THB 04:05, 17 November 2006 (UTC)

Agarwood is expensive, and people make a lot of money from it, but its only a fraction of profit worldwide from the forestry industry. Something makes me think fruit trees are the biggest moneymakers worldwide, but that's just a guess. Lowerarchy 05:44, 17 November 2006 (UTC)

Marco Polo-era China used mulberry bark as currency; check this out:[4]-- Sturgeonman 19:13, 19 November 2006 (UTC)