Wikipedia:Reference desk/Archives/Science/2020 April 11

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April 11

Covid19 test invasiveness?

I'm hearing that food handlers are having their temperatures checked daily and sent home if their temperature is elevated. I figure by the time that happens, they are infectious as hell and it would really be much better to do PCR tests. Other than shortage of testing materials, is there any big obstacle to testing people several times a week? Does it involve a very invasive and uncomfortable procedure (throat swab) or can it be done with less annoyance? I don't remember ever having a test like that, beyond "say ah". Thanks. 2601:648:8202:96B0:E0CB:579B:1F5:84ED (talk) 00:58, 11 April 2020 (UTC)

Here's a New York Magazine article that describes the process, which is an invasive and often painful procedure involving the insertion of a swab deep into the nasal cavity. Nobody would want to go through that several times a week. But the bottom line is that the United States simply does not have the capability to do that many tests at this time. Cullen³²⁸ Let's discuss it 01:47, 11 April 2020 (UTC)

Many things can elevate body temperature, not just hell-like infection. InedibleHulk (talk) 01:57, 11 April 2020 (UTC)

True enough, but no sane employer would allow an employee with a fever to work in proximity to other people during this pandemic. Cullen³²⁸ Let's discuss it 02:48, 11 April 2020 (UTC)

Aye, safer to err on the cautious side. Same with coughing or sniffing. Even more reasons for that, but ominous in today's market. InedibleHulk (talk) 20:20, 11 April 2020 (UTC)

Thanks, I don't know how many people are involved. Testing capacity is on the increase but if the tests are that invasive then yeah, doing them frequently won't work. Wonder if a less invasive test might be possible at some point, using saliva or something. 2601:648:8202:96B0:E0CB:579B:1F5:84ED (talk) 04:51, 11 April 2020 (UTC)

The second half of CRISPR And Spit Might Be Keys To Faster, Cheaper, Easier Tests For The Coronavirus (NPR, April 17, 2020, Joe Palca) discusses one ongoing attempt to make a saliva based test. -- ToE 15:20, 18 April 2020 (UTC)

azithromycin as antiviral

A few times over the years I've caught a normal cold, waited it out the usual way, found myself with a lingering cough for 1+ month afterwards, and went to the doctor who wrote a z-pack (azithromycin) script without doing any lab tests and with basically no hesitation. I was perplexed by that since I thought everyone knew antibiotics don't work on viral infections, but I went along with it and to my surprise the cough cleared up right away. I figured ok, maybe it was a secondary bacterial infection that the doctor figured out. More recently though, in the context of covid-19, I've been hearing (not just from Pres. Trump's daily infomercials) that azithromycin has antiviral properties too. Is that another possibility for what was going on with these coughs? Not asking medical advice since the most recent of these were some years ago. Just wondering what the Dr. was likely to have been thinking. Thanks. 2601:648:8202:96B0:E0CB:579B:1F5:84ED (talk) 03:35, 11 April 2020 (UTC)

They may have been thinking of the placebo effect – or indeed of a lingering superinfection with opportunistic bacteria. Azithromycin has been shown to have some antiviral action against some viruses, but not, for example, influenza viruses. It can help though against bacterial superinfections, which are often seen as complications in severe cases. As far as I know, antiviral effects against coronaviruses have not yet been established, but many clinical studies are underway.  --Lambiam 18:47, 11 April 2020 (UTC)

I like to hope doctors know better than to prescribe antibiotics as placebo. The usual situation is the opposite: patient with a cold asks for antibiotics, doctor has to refuse and explain that they don't work on viruses. I did ask the doctor about this when he prescribed the zpak but he seemed sure. Superinfection means two infections at once right? At the time of these visits, the normal cold symptoms were gone and there was only the chronic cough left. 2601:648:8202:96B0:E0CB:579B:1F5:84ED (talk) 20:45, 11 April 2020 (UTC)

The term "superinfection" means so much as a second (or third) infection; after the initial one is over it can still be called that way.  --Lambiam 20:40, 12 April 2020 (UTC)

Azithromycin has been cited as being used as a prophylactic for preventing superinfection in patients with covid19. It may be favored in general or in specific patient subpopulations (such as pregnant women) due to perceptions of being one of the safer antibiotics. It does have evidence of in vitro effectiveness at preventing replication of some viruses, though the mechanism of action for this is unknown.[1][2]. Someguy1221 (talk) 19:51, 18 April 2020 (UTC)

What constitutes a colonial organism?

Siphonophorae. These cells may be separate, but they are not individuals, are they..

In relation to the recent discovery of a clonal, colony organism (a Siphonophore). The article I read is short[3], but it is from the American Association for the Advancement of Science, who I have always taken for granted to be a highly respectable source. It describes the organism as a single organism, i.e., the longest organism ever discovered.

When I started to read up about this, taking the news for granted, I realised that there would be some contention that this was indeed an individual organism. The creatures which comprise this organism are genetically identical singular celled organisms, except for mutations/genetic drifting.

I am asking, is there any material which supports or debates the idea that, if the only difference between an individual organism and a colony is that they are not physically attached, do they constitute an individual organism?

Should we describe this creature as the longest organism ever discovered, as the AAAS article has... or what? ~ R.T.G 03:54, 11 April 2020 (UTC)

I thought the biggest single organism was supposed to be a fungus covering 2000+ acres in Oregon.[4] We have an article Largest organisms listing other possibilities. 2601:648:8202:96B0:E0CB:579B:1F5:84ED (talk) 04:53, 11 April 2020 (UTC)

This is the longest. ~ R.T.G 15:44, 11 April 2020 (UTC)

By what measure? It's not realistic that something 120 metres/0.12 km is longer than an organism covering 965 hectares (9.65 km²). Even longer than one covering 43 hectares (0.43 km²) like Pando (tree)) is impossible unless you come up with some very weird definition. Remember that means ~0.65 km x 0.65 km if a perfect square. While Science (journal) is a highly respect journal, their internet news is still prone to the sort of stuff like sensationalistic inaccurate hyperbole that most science news stories are prone to. Maybe they're a little better than most random media reports but not by much. I mean the source they cite, Newsweek, doesn't even make the claim AFAICT [5]. BTW clonal colony is what you want, not colony organism.If you want to find out more about large clonal colonies like Pando and Armillaria ostoyae, check out the clonal colony article. Nil Einne (talk) 17:07, 11 April 2020 (UTC) 17:46, 11 April 2020 (UTC)

The headline says "Longest deep-sea animal", not longest animal. Rmhermen (talk) 19:06, 11 April 2020 (UTC)

I found that, Nil. It was linked in the OP. What I want is to describe an argument that says a clonal colony may constitute a single being, such as in this case, where it clearly is that. I accept that the trees and fungus are bonded at the roots, but these are individual animals in this case. It's quite a step aside from those. Just look at those pictures. It is not a colony of trees with bonded roots or a colony of penguins as the articles we use to define. These are complex... thingies. We've got to do better than letting the reader call them thingy. They are fascinating. There must be material on that. The AAAS seems to agree. ~ R.T.G 19:27, 11 April 2020 (UTC)

The Science mag article has a slight error. The zooids are not single cells, they are multicellular. That's what makes these things colonies. They are groups of multicellular organisms where each organism is modified for a specific function. But I think you are trying to force the concept of "individual" into situations where it really isn't so clear cut. --Khajidha (talk) 21:28, 11 April 2020 (UTC)

They may be multicellular, but none of them are individual. It is the organism on the whole which would seem to be the individual. This is a valid perspective, and therefore Wikipedia should be reflecting it in the same way it does regarding the trees with the bonded roots and the fungus Nil Einne refers to above. I'm not trying to force anything on anyone. I'm looking for a reliable source which claims it is a valid perspective to consider organisms such as the siphonophorae to be individual organisms on the whole. Without support for that perspective, a misleading impression is given without a clear accompanying image, therefore it is essential. ~ R.T.G 00:49, 13 April 2020 (UTC)

Universe density without expansion

Without expansion, would the Universe gradually become more dense (due to various processes, such as supernova explosions, etc which in my understanding increase the gas volume), ultimately to the point when the interstellar medium starts to propagate sound? And is the acceleration of expansion critical to offset possible density increase? Thanks. 212.180.235.46 (talk)

If you take Hoyle's quasi-steady state model and leave out the expansion, the model predicts increasing density. But barring the creation of new mass (which would violate the conservation of energy), the average density should remain the same. If, however, all mass is equally distributed in a homogeneous universe, the density will be higher than the current density of the interstellar medium. I have not attempted to see whether the (then universal) medium will have the characteristics of a gas. (If is is a plasma, sound waves will be subject to Landau damping.)  --Lambiam 18:22, 11 April 2020 (UTC)

There will be no one to hear you shout, though.  --Lambiam 18:53, 11 April 2020 (UTC)

First question, I don't think a supernova explosion can increase the gas volume: even a supernova cannot produce more mass than the original star had in the first place, can it? And even less, because some percent of the original mass are lost in the form of radiation. Generally I don't see how this universe could become more dense without creation of matter if it doesn't contract.

Second question, our article Stellar density says that the estimated average density of star matter in the region of our Sun is about 4 × 10⁻²⁴ g/cm³. In the central regions of the galaxy it should be some 500 times higher, that is 2 × 10⁻²¹ g/cm³, much less out of the galactic plane (the density of the air near sea level is about 1,2 g^-3/cm³, the density of free neutral hydrogen in the galaxy is estimated to be some 2% of the total mass, the density of neutral hydrogen between galaxies is estimated to be 6% of that inside galaxies). If you consider the huge extension of star free space between galaxies, the average density of the universe must lie rather near zero, so it would not propagate sound in any case. 2003:F5:6F0F:7100:DD51:BDFE:19D5:D8C6 (talk) 14:56, 12 April 2020 (UTC) Marco PB

The speed of sound in an ideal gas depends only on its temperature and composition. If gas-like, the homogeneous interstellar medium would closely resemble an ideal monomolecular gas, so sound would propagate with a speed only determined by the temperature – the hotter the faster. It may be faint, but that does not mean it does not propagate.  --Lambiam 20:33, 12 April 2020 (UTC)

This is just theory. As far as our question is concerned ("when the interstellar medium starts to propagate sound?") not sound speed but intensity is relevant, and if it is said that in the not really empty space between Earth and Moon no sounds are udible, so much less udible will be sounds in a "gas" as described above containing maybe 1 hydrogem molecule per cubic cemtimeter, where the free path for an accelerated atom (the way it must run in average before it hits another one) is in the range of several 1000 miles. So in my opinion the answer to the question above remains "never ever" 2003:F5:6F14:7B00:4999:52FA:30FB:CA06 (talk) 23:11, 13 April 2020 (UTC) Marco PM

We say that the universe is expanding and contracting, but in fact it more like it is stretching and contracting than growing by adding mass. The mass of the universe changes as a result of stretching, no more than the mass of a rubber band changes as a result of stretching... Which is to say that it doesn't... ~ R.T.G 01:10, 13 April 2020 (UTC)

Some theories, like that of Hoyle, allow the creation of new matter. But also with an invariant amount of matter, making space homogeneous will increase the density in formerly low-density areas (the interstellar medium) while decreasing it in formerly high-density areas (such as stars).  --Lambiam 14:44, 13 April 2020 (UTC)

The above is interesting discussion, but for an in-a-nutshell reply to the original query: I am fairly sure there just isn't enough stuff in the observable universe for that. Now the cool thing is right after the Big Bang, this actually was the case, except for the whole universe! Cosmologists call these by the fancy science term "baryon acoustic oscillations", which, if you know the vocabulary, just means "sound waves traveling through ordinary matter". Baryons are a type of particle that includes protons and neutrons. Eventually the universe expanded to the point that the density became too low for these to continue propagating, and the patterns of matter at that time "seeded" the resulting structure in the universe as gravity took over. Since no new mass is being added to the universe, all that's happened since then has been gravity pulling matter towards regions of higher density, except when overpowered by other forces as in things like supernovas. But the universe is just enormous, so even within galaxies it remains basically empty of ordinary matter outside of astronomical objects like stars and planets. There is of course dark matter, which is a big mystery at present so we can't say much about it other than it interacts gravitationally. --47.146.63.87 (talk) 00:08, 14 April 2020 (UTC)

COVID-19 epidemiological models

Is it possible that when this is over, it could turn out that the models showed overestimated outcomes from overly pessimistic assumptions and that more limited quarantines and containment measures could have been just as effective? 90.198.251.144 (talk) 08:42, 11 April 2020 (UTC)

You mean could some particular measures here or there not been needed? Probably. Or could better preparation, monitoring, testing etc. have substituted for some of the quarantines? Also probably (the lack of facilities for that count as poor preparation). Overall though it's already established that the containment efforts, especially at the beginning, were too little rather than too much; and that's why we're in such trouble now. 2601:648:8202:96B0:E0CB:579B:1F5:84ED (talk) 10:58, 11 April 2020 (UTC)

So in other words, early containment would have been best but the trouble were in now due to leaving it too late means that public policy is generally going for the worst case scenario and doing blanket restrictions so as to not take any chances? 90.198.251.144 (talk) 11:37, 11 April 2020 (UTC)

It doesn't take all that much to reduce the basic reproduction rate, R_0, of the virus to a bit below 1, say 0.8. That's good enough if there are a large number of cases and the ICUs are overflowing, then bringing down the R_0 is not good enough. You want to have a far lower R_0 to bring down the number of cases on a short time scale of a few weeks. This then requires far more rigorous measures. Count Iblis (talk) 12:08, 11 April 2020 (UTC)

The reason most countries did not go for early containment and also delayed taking action on developing testing capabilities is that the politicians who set public policy were far too optimistic. If they had gone, among the plausible scenarios, for the worst case scenario (a highly contagious airborne disease with far higher mortality rate than the flu), the world would be better off now.  --Lambiam 18:08, 11 April 2020 (UTC)

So is it possible some places have now gone too far the other way? 90.198.251.144 (talk) 21:08, 11 April 2020 (UTC)

Possible? Sure. But one has to be careful going to that conclusion. Especially, those without training and knowledge needed have to be careful going to that conclusion. Let me put it this way, lots of antivaxxers say we have gone too far with vaccination programs against things like measles and polio. After all, they don't know anyone who died or suffered ill effects from either measles or polio. Is that evidence that vaccination programs have gone too far? Or is that the actual intended result of the vaccination program? The entire point of vaccination is to make it that none of us experience the ill effects of these diseases, so if they are successful, we also will never know anyone who suffered from measles or polio. The same thing applies to these quarantine and containment measures. When they first started, we all saw people saying "only a few thousand are infected, and no one I know, this is overkill." If it becomes "only 60,000 Americans died, barely more than a normal flu year, this was overkill," then the people saying that are missing the entire point. These measures kept the numbers down so that only, say, 60,000 Americans died. The number being that low is the success of these containment measures, not evidence of overkill. If these measures had not been put into place, or if they are lifted too early, the numbers would be far, far higher. --OuroborosCobra (talk) 21:15, 11 April 2020 (UTC)

Politicians are now talking about letting up and it is way too soon for that. No things haven't gone too far: they haven't gone far enough. Check out the article about the last big pandemic, the 1918 Spanish flu. You will see there were two big waves of fatalities and the second wave was worse than the first. The second wave happened because the quarantine measures from the first were let up too early. 2601:648:8202:96B0:E0CB:579B:1F5:84ED (talk) 22:19, 11 April 2020 (UTC)

Kinetic energies in a non-head-on collision

We know that the kinetic energy of a system is conserved only in completely elastic collisions. Namely, in otherwise inelastic collisions the system loses kinetic energy. However, in non-head-on collision it seems that this principle doesn't hold. For example, assume a mass moving with 8 m\sec towards a stationary object double its mass, and impacting it. As a result, the 1st body recoils 135 degrees with respect to the original direction of the 1st, and the 2nd body recoils 30 degrees with respect to it. Now, detailed calculations yield results (15.44 m\sec & 10.93 m\sec, respectively) that obey the coservation of linear momentum, but seems wrong regarding the total of the kinetic energy of the system - it turns out to be higher than its initial value, which isn't reasonable. I wonder what's wrong here, in principle (the calculations are correct) ?? Thanks, בנצי (talk) 15:35, 11 April 2020 (UTC)

You cannot freely set both angles. In an elastic collision, there is a relation between the angles. Basically, there are 4 degrees of freedom, 3 of which are constrained by the conversation laws, so you have only one dof left.  --Lambiam 17:42, 11 April 2020 (UTC)

Thank you for your elaboration. In what textbook or reference, you might know of, can I find detailed discussion & examples regarding this topic ? בנצי (talk) 20:34, 11 April 2020 (UTC)

In particular, where consideration of the degrees of freedom is described ?

According to what you stated, both angles can't be simultaneously set, since the impacting bodies should remain on one line. The other two degrees of freedom aren't set, so it remain the slight difference in angle (5 degrees) to 'justify' the huge difference in the total kinetic energy of the system, which doesn't seem to be reasonable, and there must be more to it. בנצי (talk) 22:20, 12 April 2020 (UTC)

In the center of mass frame, the total momentum is zero and the kinetic energy is proportional to the momentum of either mass. So, energy and momentum conservation implies that in the center of mass frame, the two particles move away from each other after the collision along a line that's rotated by some angle relative to the original trajectory. If you keep that angle arbitrary and transform back to the original frame, you'll have the set of all possible elastic collision outcomes. Count Iblis (talk) 17:44, 11 April 2020 (UTC)

Thank you too. Very interesting remark. Where do you think I can find detailed discussion regarding the relation between trajectories & angle of rotation ? בנצי (talk) 20:34, 11 April 2020 (UTC)

Derive it :) I think it's an exercise in my old classical mechanics book... Count Iblis (talk) 22:49, 11 April 2020 (UTC)

What book is it ? Its author ? בנצי (talk) 22:03, 12 April 2020 (UTC)

I'll try to find it. Count Iblis (talk) 19:39, 17 April 2020 (UTC)

As an interesting special case, a corollary is that if the two bodies have equal mass and one was initially at rest, after the collision they will move away at a right angle to each other.  --Lambiam 17:56, 11 April 2020 (UTC)

Right. It's a direct consequence of the momentum vectors being related by Pythagorean triangle, according to what's given. This specific condition makes an excellent experimental demonstration. בנצי (talk) 20:34, 11 April 2020 (UTC)

Coronavirus science

Why are different countries taking such a different approach in managing their epidemic? Is the science different in each country? 90.198.251.144 (talk) 17:03, 11 April 2020 (UTC)

The different approaches are because of the difference in politicians not the scientists. MarnetteD|Talk 17:12, 11 April 2020 (UTC)

And these differences are mainly those between politicians who are willing to listen to what the scientists have to tell us, and politicians who think they know everything better than anyone else, including the scientists.  --Lambiam 17:35, 11 April 2020 (UTC)

There seems to be differences in the science as well though? Such as Sweden? 90.198.251.144 (talk) 18:20, 11 April 2020 (UTC)

Yes, that is why I wrote "mainly".  --Lambiam 06:59, 12 April 2020 (UTC)

(EC) Politicians are a big factor, but IMO it's inaccurate to say it's entirely politicians. Sweden's approach for example keeps getting a lot of attention [6] [7] [8] [9] [10]. Yet as some of those sources note, their public health agency is noted for their relative level of independence. And it seems more accurate to call the people in charge like Anders Tegnell, scientists than politicians. Does that mean the different decisions in plenty of other countries came from the politicians with scientists thinking they are a dumb idea? Well no, I think the pushback against UK's earlier plans which seemed more similar to Sweden, or WTF Trump is going at any given time, indicates strongly against that.

Meanwhile for a long time many countries in the West, especially the Anglophone ones, were against the general public wearing masks when not showing symptoms. I think there's strong evidence that this came from the views of scientists not politicians. Perhaps their decision was in part influenced by politicians having screwed up and not having enough masks, but as I said the last time this came up, I think the evidence suggests there was a genuine belief they were not beneficial. However, in some places like China and South Korea, mask use was compulsory in a number of cases, and strongly recommended in others. Were these countries giving differing advice solely due to "politicians"? Again I think the evidence suggests it was at least partly based on a differing scientific view.

You also get the occasional pushback or questions about some measure from economists and others who can't reasonably be called politicians. [11] [12] [13] [14] While broadly, they seem to support what many countries have done e.g.[15], it hard to disagree you have to consider the wider implications of any measure you take. People dying from the virus is clearly a terrible thing, but so too is people dying from starvation or rioting or other things if your country collapses. And especially in some parts of the developing world, there are genuine concerns about how they will cope with long term locks downs.

Talking about different countries situations also highlights one final point. It seems clear that different countries based on their different situations but also different advice think they may be able to achieve different things. NZ for example, with no land borders, a small size, low density etc clearly think that we can eliminate it [16], then try to keep it out via tough border restrictions then well less clear but probably hope for a vaccine, the rest of the world fixes the mess or some other solution. China seems to sort of be hoping that as well. It's less clear for some other developed countries. And for a number of developing ones even Iran, it doesn't seem they believe they can achieve this. Again, it seems questionable to just say this is "politicians", it seems quite likely that some scientific advisors and others believe it's simply not possible given their countries resources and the nature of the disease.

In fact, if we go back to South Korea which despite their problems avoided a nationwide lockdown [17], this came in part from capabilities and measures which even a number of developed countries probably couldn't achieve even if we put aside their plenty of missteps. As with my earlier comment, you could go back and blame politicians for not doing stuff years before to get everything into place but that seems a stretch. Even those missteps can IMO be complicated. For example, is it only "politicians" at fault for whatever happened in Italy, or was there a lot that went wrong for a bunch of reasons probably including "luck"?

Note that I'm not suggesting politics didn't also come into any of these decisions. Rather, simply that it wasn't the only factor and in a number of cases, I'm not even convinced it was the main factor.

Nil Einne (talk) 18:38, 11 April 2020 (UTC)

Since the above is very long, to give one highly specific example that is still a "different approach" even if fairly minor. In NZ, our current "level 4" means all restaurants etc are closed including for takeaway and deliveries. Meals on wheels services for the elderly and others who cannot cook for themselves are allowed, but otherwise you need to either cook or use commercial prepared meals from the supermarket etc. While some countries have done the same thing, a number of others with relatively strict lockdowns haven't. Even parts of? Italy, and New York, haven't from what I understand [18] [19]. Is this solely because of "politicians" or also for other reasons like the norms in the different places such as cooking facilities in the places of residence? Nil Einne (talk) 18:57, 11 April 2020 (UTC)

The World Health Organization is to blame here at least in part, because it doesn't have a single master plan to enact in case of pandemics (despite the organization's blueprint priority diseases). This means every country is left on its own. Brandmeister^talk 23:13, 11 April 2020 (UTC)

Given that a lot of countries have historically demonised the WHO and related bodies, would you expect any single master plan to have been followed anyway? HiLo48 (talk) 02:34, 12 April 2020 (UTC)

Had the WHO been effective, it would probably have not been demonised. Brandmeister^talk 07:41, 12 April 2020 (UTC)

It may not be that simple. Politicians (well, people) like to demonize things, large international orgs not the least among them. Gråbergs Gråa Sång (talk) 08:42, 12 April 2020 (UTC)

The policies of the WHO are set by the World Health Assembly. The US delegation to the WHA 2019 consisted of Alex Azar, Theodore Allegra and Brett Giroir.^{[20] (pdf)} Azar is a Juris Doctor and former lobbyist for the pharmaceutical industry. Allegra is a Juris Doctor and career diplomat. Only Giroir has credentials for medical expertise, but there are indications ideological considerations may affect his decisions.^[21] While accompanied by a large retinue of alternates, it is the official delegation that in the end decides how to vote. I have not looked at the delegations from other countries, but I would not be surprised if also overall the role of medical experts in setting the WHO policies is less than one should hope. One of the recommendations by an independent panel on the response to the Ebola epidemic convened by Harvard Global Health Institute and the London School of Hygiene & Tropical Medicine, chaired by Peter Piot, was to set up a transparent and politically protected WHO Standing Emergency Committee, delegated with the responsibility for declaring public health emergencies. The bit I have underlined underscores that the role of politics is not imaginary.  --Lambiam 08:56, 12 April 2020 (UTC)

I think that highlights a particular important point that people often missed. While there is a lot of bureaucracy etc, most international organisations of that form are also strongly influenced by national and international politics. Despite all the "new world order" nonsense people like to talk about, in reality these organisations tend to be incredibly heavily influenced by national governments who both hold the purse strings and also generally have a big influence in the people in charge. For example, there is a lot of controversy over the WHO and Taiwan which has flared up recently, yet there's clearly no easy solution. It's not like the WHO can just say fuck you to China and expect China to continue to work with them. If they piss off China enough, China will work very hard to either change what they are doing, or destroy them. It is true that given the way international organisations work, influence is often some weird combination of who has power in the world (which depends on several things like size, GDP etc), who is paying the most money, and each member country (regardless of population, size, GDP etc). Nil Einne (talk) 20:03, 12 April 2020 (UTC)

That's simply not plausible since plenty of effective international organisations are demonised. While this is the science desk and not humanities, I'll be blunt that I don't think someone who believes a massive international organisation won't be demonised solely because it's effective, understands world affairs enough to comment on matters like this. Nil Einne (talk) 20:03, 12 April 2020 (UTC)

Well the WHO advocated extensive testing yet many countries who should have been able to, failed badly on that score. One country even decided to make their own primers, and utterly failed. Nil Einne (talk) 19:50, 12 April 2020 (UTC)

P.S. This is not to say the WHO hasn't failed as well, clearly they also have failings. But as per the main point of my early reply, there is really no single entity which you can say is "to blame". And frankly the WHO would be low down on my list because as I said in the other recently replies, it's simply not plausible given the way international politics works, that the WHO could come up with some master plan that all the world would follow, especially since it will depend on the specifics of disease X (how it spreads, where it originated from, when it is recognised, etc etc etc) and again getting back to a point of my original replies, there is no one plan that will work for all countries.

Something that works in a developed country with a good healthcare system and technological advanced country like South Korea is probably not going to work in a country like Yemen where so much is destroyed by an ongoing war and where even now the parties to that war are still bickering over a ceasefire. Now a good plan may have options for each scenario or differing case, but that means as I said, that things are still going to be different between places even if there was such a plan which was another one of the points I was trying to get across. I'd suggest that even if we put aside the lack of resources or the unlikelyhood of people following it, a sufficiently detailed plan for each eventuality is not really plausible anyway. And then even if you did make such a plan, things can change fairly fast.

If we put aside such active wars, what may have worked in Venezuela 10 years ago may not work now. 7 years ago any plan for Crimea would have mostly involved Ukraine. Now it has to mostly involve Russia. Not to mention the population changes that resulted, e.g. what's happened to the Crimean Tatars. 57 years ago, any plan wouldn't have assumed that Uyghurs were in concentration camps. Now it needs to take that into consideration. 5 years ago, any plan would likely have assumed a far great competence from the US CDC than they have shown so far. (Frankly, I'm not even sure whether many in the US expected the CDC to fail so badly.) 5 years ago any plan would have taken into account that the UK was part of the EU. Etc etc etc etc etc.

Nil Einne (talk) 20:31, 12 April 2020 (UTC) 22:40, 12 April 2020 (UTC)

Again the above is very long, so I'll give one specific example which also nicely ties this into science. If you look at comments both in the early days and later of the 2020 Hubei lockdowns, especially the Wuhan one, I think it's clear even among experts that there was a lot of uncertainty over whether these measures would work [22] [23] [24]. While social distancing measures were understodo to be beneficial, no one had every done some so radically on such a massive scale in the modern world. (The WHO Representative in China said the same thing [25].) Even if it may work in China, there was a lot of belief that what may work in an authoritarian regime like China, would fail in a place where there was greater demand and expectations of individual freedoms. But once the evidence began to emerge how it was working in Wuhan and other parts of China, suddenly everyone started to contemplate it. How could anyone come up with a plan, based on something many experts weren't sure would work? Frankly, if the first epicentre had been Texas or something, even if the government had implemented a Wuhan style lockdown, I'm not convinced it would have worked given the likely greater level of pushback when there was limited evidence of effectiveness. Nil Einne (talk) 21:16, 12 April 2020 (UTC)

Possible stabilization of muons

Since free neutrons are unstable but are stable inside a nucleus, maybe the very unstable muons could be partially stabilized by injecting them into a nucleus?Rich (talk) 19:10, 11 April 2020 (UTC)

Muons are not hadrons and can not "injected" into nucleus. Ruslik_Zero 20:15, 11 April 2020 (UTC)

“Can not” as in theoretically impossible and absolutely impossible or just as in no known technique at present? If muons created by a collision of a cosmic ray in the atmosphere collided by chance with an oxygen atom, I would think it could approach more closely to the oxygen nucleus than before being repelled by the electron cloud than a stray electron could being much lighter than a muon. There are certainly electon beams in the semiconductor industry that are aimed at silicon wafers, and surely some electrons end up going straight at the nucleus of a silicon atom before being deflected by the electron cloud. So what would help a lot is if you were more explanatory, less terse, in your answers and provided citations.Rich (talk) 21:31, 11 April 2020 (UTC)

Muons are leptons so do not feel the strong nuclear force, so they will not be captured in the nucleus. They could replace an electron though. Dja1979 (talk) 07:28, 12 April 2020 (UTC)

Well there's the idea of muonium, not exactly the same thing. Read this post and the linked posts by particle physicist Matt Strassler for an understanding of what makes a system of particles stable. The muon doesn't participate in the strong interaction, which is what holds nuclei together (indirectly through the nuclear force); it's not going to become bound in a nucleus. --47.146.63.87 (talk) 23:05, 11 April 2020 (UTC)

Yes, I’ll read the Strassler piece thanks. But since both the neutron and the muon decay by the weak interaction, and being in a nucleus stabilizes the neutron, why shouldn’t we think there is a chance that a nucleus stabilizes muons? Is it to do with Rusniks cryptic hint that the muon isn’t a hadron? I’d like to know more in order to accept Rusniks claims. I already am skeptical about the “can not “inject”” which seemed mainly motivated by the desire to be sarcastic by injecting “ “ marks.Rich (talk) 01:20, 12 April 2020 (UTC)

The weak interaction has a ridiculously-short range—less than a proton diameter—because its carrier particles are so massive. Consequently it doesn't produce bound states. I presume the reference to hadrons was alluding to muons being leptons, meaning they don't experience the strong interaction. Protons and neutrons are hadrons, and of course they're what make up atomic nuclei; hadrons are composite particles bound by the strong interaction. So the core point is, the muon "doesn't care" whether it's near a nucleus or not, at least in terms of any effect on its lifetime. It only can interact with a nucleus via electromagnetism or gravity, neither of which affect its decay, which is mediated by the weak interaction. --47.146.63.87 (talk) 23:10, 12 April 2020 (UTC)

A muon in a degenerate electron gas where all the states up to the decay energy of the mun are occupied, will make the muon stable. Count Iblis (talk) 01:40, 12 April 2020 (UTC)

So muons could be stable inside a White dwarf?Rich (talk) 04:52, 12 April 2020 (UTC)

A neutron can decay to a proton, an electron and an antineutrino. The combined mass (and thus energy) of those particles is slightly less than that of a neutron, so this is energetically possible.

Once the neutron is in an atomic nucleus, the binding energy (which is negative) has to be taken into account. If the binding energy of the neutron is sufficiently less (more negative) than that of the resulting proton after decay, the decay is no longer energetically favourable and won't happen. Then the neutron is stable. In atomic nuclei with too many neutrons the binding energy of the neutron is too high for this, so these nuclei emit beta radiation.

Muons aren't subject to the strong force and therefore experience no significant binding energy in a nucleus. There's only the electromagnetic force, and even then, that provides the same binding energy to an electron as to a muon, so that won't help.

Can a muon be stable inside a white dwarf? No. The rest mass of a muon is 207 times the rest mass of an electron, so to occupy all energy states up to the decay energy of the muon, the electron gas has to be highly relativistic. When the electrons turn relativistic, the white dwarf hits the Chandrasekhar limit and collapses. PiusImpavidus (talk) 10:57, 12 April 2020 (UTC)

But the muon is negatively charged, so if it were in a nucleus, it would be attracted to the protons, so it would come quite close to protons-wouldn’t that allow the weak force to come into play?Rich (talk) 14:30, 13 April 2020 (UTC)

Can a muon near a nucleus have lower energy than a muon and a nucleus at some distance? Yes (because of electrostatic attraction), so the muon can exist in a bound state around a nucleus. Will a muon in a nucleus have lower energy than an electron, <bar>ν</bar>_e, ν_μ in the same nucleus? No, so the muon will still decay into those products even if it's near a nucleus. --Amble (talk) 18:30, 13 April 2020 (UTC)

See also Muonic hydrogen or Muonic atom for what actually happens. Graeme Bartlett (talk) 21:34, 13 April 2020 (UTC)

Do fat people eat more?

There's an older guy living here who was athletic in the past, but has become sedentary and rather paunchy over the years. He has apparently put on considerable weight in the past 2 years in particular. Question: does the extra fat give the person a bigger appetite, like to generate the energy to keep it jiggling or anything like that? That's been a subject of discussion around here (as someone said in Coneheads (film), "the boy likes to eat") so I'm wondering if it's a known thing. Not medical, just diet. Thanks. 2601:648:8202:96B0:E0CB:579B:1F5:84ED (talk) 21:38, 11 April 2020 (UTC)

They are fat because they eat more fat: see here. Count Iblis (talk) 22:54, 11 April 2020 (UTC)

Michael Klaper is not a reliable source, arguably a WP:FRINGE source. Also, unused carbohydrates convert to fat -- that's middle school health class knowledge. Hell, even Dr. Nick seems to get that. Ian.thomson (talk) 23:45, 11 April 2020 (UTC)

Fringe but 100% correct, while the official reliable sources have promoted pseudoscientific nonsense as proper science. The way most of the research is done is heavily biased in favor of the extremely unhealthy Western diets where a large chunk of the calories come from refined fats and refined carbs. It's, of course, difficult to do a controlled trial where you compare diets with totally different energy densities. If you're not used to eating a low energy density diet, then getting used to that will take a few years. There are plenty of research papers on populations that stick to such diets, but the results of these studies, like this study, or this study are not used for the guidelines for diet. Nope, we prefer controlled trials of diets, which amounts to being heavily biased toward a Western-type diet as these are the only types of diets people in the West are actually capable of eating.

One of the biggest pieces of pseudoscientific nonsense dietitians have come up with, is this whole idea that eating more calories causes people to get overweight. If that were true, then animals could never have evolved. Indigenous people don't do calorie counting, they eat their belly full with all the food they can find. Obesity is extremely rare in such populations. The standard explanation of that fact is that indigenous populations are teetering on the brink of starvation. But they and animals that live in the wild are typically not close to starvation at all. The fact that they typically don't get obese then does require a fine tuning of the metabolic rate to the calorie intake, but this is obviously regulated by the body itself and not due to some massive coincidence.

Clearly, it's the large amounts of refined fat in the Western diet that makes people get used to eating unnaturally small portions of foods. They then don't get all the nutrients the body needs to optimally regulate the metabolism to match the calorie intake. For example, I eat close to 4000 Kcal worth of whole-foods a day, but I weigh just 53 kg. But I get 100 grams of fiber a day, 1.2 grams of magnesium. Most people get only 20 grams of fiber a day. My body is able to burn the 4000 Kcal/ day, while most people who weight a lot more than I do are only capable of burning 2000 Kcal/day. Count Iblis (talk) 01:03, 12 April 2020 (UTC)

@Count Iblis: You do know that there's discretionary sanctions in place for alternative medicine and pseudoscience? Ian.thomson (talk) 10:40, 12 April 2020 (UTC)

Pseudoscience or no pseudoscience, you admitted below that you've been struggling with your weight. I eat way more calories than than you do, and I'm not struggling with my weight. I'm extremely fit, I run an hour a day. Many of my friends who stick to what is regarded as a normal diet, are struggling with their weight, they are not fit. Note that it wasn't all that long ago that the exercise was regarded as unnecessary for health and even potentially harmful for health. People advocating exercise and fitness were regarded as pseudoscientific quacks by the medical community. See here: "People thought I was a charlatan and a nut. The doctors were against me‍—‌they said that working out with weights would give people heart attacks and they would lose their sex drive.". Thing is that medicine is fundamentally not about health, the research methods used in medicine make it totally unsuitable to make good judgement about what is healthy or not for people who are generally healthy. Count Iblis (talk) 11:40, 12 April 2020 (UTC)

Well said! Healthy food, lots of water, and just a little bit of exercise does indeed go a long way in helping to keep the old vim and vigour. Some people just don't get it though... Earl of Arundel (talk) 17:37, 12 April 2020 (UTC)

@Count Iblis: If you actually read my post, you'd see that I pointed out that it's ultimately diet and exercise -- without citing quacks or promoting pseudoscience. Stop giving charlatans credit by pointing out the little bit they kinda get right by throwing on a bunch of utter lies on top of it. Ian.thomson (talk) 21:48, 12 April 2020 (UTC)

This is Iblis's major MO for answering nutrition questions at Wikipedia. He shares information from obviously bogus sources that get maybe 10% of what they say right, and 90% of which is hokum. He pretends that because the 10% is the sort of broadly-true-and-well-known stuff like "if you eat less calories, you gain less weight" sort of stuff, that somehow the rest of the snake-oil-salesman bullshit they pedal must also be reliable. It isn't. I have learned that literally nothing Iblis says about nutrition should ever be listened to; and that anything he coincidentally gets right could have been learned from a source that actually knows what they are talking about. He's shown himself to be utterly unreliable in these regards for years, and should be always both ignored on the substance of his posts, and called out for trying to convince the others of his entirely unreliable information. --Jayron32 14:26, 13 April 2020 (UTC)

The facts are clear "A high carbohydrate diet of rice, plantain, manioc and corn, with a small amount of wild game and fish – plus around six hours’ exercise every day – has given the Tsimané people of the Bolivian Amazon the healthiest hearts in the world.....

The study published in the Lancet medical journal and being presented at the American College of Cardiology conference shows that an 80-year-old Tsimané man has the vascular age of an American in his mid-50s....Most of the Tsimané are able to live their entire life without developing any coronary atherosclerosis. This has never been seen in any prior research. While difficult to achieve in the industrialized world, we can adopt some aspects of their lifestyle to potentially forestall a condition we thought would eventually effect almost all of us."

The way the official advice on diet is determined is also clear "Dr Aune said the findings did not mean the five-a-day message needed to change. He told the BBC: "There are many different considerations if changing policy, it's not just the health effects - is it feasible?"

So, it's judged to not be feasible. It's already difficult enough to convince the Big Mac gorging population to also eat a bit of fruits and vegetables every day. Most of them don't even stick to that advice, so if we were to tell them the truth, they would likely give up on eating fruits and vegetables altogether. You then get your information from these sources that downplay the relation between diet and health. If someone tells you something different then you won't listen do those people. In your opinion they are clearly quacks because they are saying something different than what you read in the sources that whitewash your diet and lifestyle. Count Iblis (talk) 20:46, 13 April 2020 (UTC)

I haven't said any of those things. I have said that your existing record makes your existing trustworthiness to not spread quackery suspect enough to ignore you. If you sometimes post a proper study with good information, that's irrelevant to my point. I never said to reliably do the opposite of what you state, even a broken clock is right twice a day. You've just shown a proclivity to deal in quackery, and to cherry pick an occasional reliable source when you can use the information in that source to support your quackery. I'm also not saying that merely because you've noted that a people group that runs 5 miles a day shows good heart health means we should not run 5 miles per day. That's probably good advice, as exercise is strongly linked to good heart health. So don't gaslight us and pretend like we're saying your information is consistently wrong. Your sources are consistently unreliable and cherry picked to advance a particular perspective which is not otherwise supported by mainstream sources. --Jayron32 12:34, 15 April 2020 (UTC)

No, the rigorous science comes first. And because this then isn't taken seriously on bogus grounds (like e.g. that only controlled trials are reliable and population-based studies cannot be used unless verified by controlled trials), you will get health gurus who I admit do also inject bogus arguments to advocate for a different lifestyle regime. But it's the results from population based studies that you cannot get from controlled trials, that is the main argument for a different approach on lifestyle. An example is this reprint from an old Lancet article. The observations are clear, but it's not considered to be a good enough argument for the statement that you can reduce your risk of cardiovascular disease to almost zero if you eat in the way the African population was eating, because for such a statement you would have to do a controlled trial. But the problem is that doing such a controlled trial is virtually impossible because a low fat diet that 's also low in refined carbs has a much lower energy density, it takes years for your body to get used to eating a much larger volume of food. And you may actually never get fully used to such a diet unless you start eating this way at childhood.

Then having ignored these sorts of results on the grounds of "it's not a controlled trial", people like Greger, Esselstyn, Klaper etc. advocate for a different approach on heat. But they inject their own advocacy for veganism, their own theories on how oil damages arteries, how certain amino acids leach calcium from bones etc. etc. Then all those things they add themselves based on tenuous science may all be wrong, but that doesn't change to original observations of Shaper et. al. that the African population of Uganda rarely suffered heart attacks. And it's not that these scientific results do not get replicated, see e.g. here.

Now, in case of exercise we would have the same problem, were it not for the quacks of decades ago that advocated for strenuous exercise when the official medical advice was that strenuous exercise is damaging to the heart due to the strain on the heart causing wear and tear. This medical opinion only changed due to the availability of a large amount of data of people having stuck to dong strenuous exercise for many years. Indigenous populations doing that would not have cut it, as they would not have been regarded to be representative enough for the western population, so any such results would have been dismissed. It still took a long time for the medical community to change its views of exercise because the preferred method of controlled trials cannot be used. But the data on millions of Western people doing strenuous exercise was just too hard to be ignored.

Just imagine what would have happened had the entire population stuck to the medical advice to avoid strenuous exercise. Then the medical community would not have had the data to overrule their apparently very sound theory that strenuous exercise is damaging to the hear.The data from observations on indigenous populations would not cut it. That leaves you with doing controlled studies. Those controlled studies would involve letting exercise intolerant couch potatoes do a very limited amount of exercise and compare any health effects that has on a control group that plays video games all day long. Whatever conclusions one can draw from that would be a far cry from the far more rigorous conclusions on heart health that we can draw from our data. But there would then be the so-called quacks that then look at the data from indigenous populations, inject their own unreliable theories into that and then argue that we should actually exercise a lot more. You would then have called me out for having cited a quack, but you then fail to see the proper context for that. Count Iblis (talk) 18:49, 15 April 2020 (UTC)

It's gonna depend on the person in question. For most people (assuming there's not a glandular problem), it's a matter of how many calories you put in against how many calories you burn during the day ([26] [27] [28]). The amount you burn, even at bedrest, is going to vary between two individuals. The Glycemic index of the food you eat matters as well as nutrition, since getting the right number of calories can be a moot point if you're not getting the right vitamins, minerals, lipids, etc ([29] [30] [31]).

(Provided as example, not doctrine): when I first arrived in Japan, I was 110 kg. I was losing weight (about two kg the first month, then one a month after until I got to around 103) while still consuming over 3000 calories a day of whatever the hell I wanted (five meals a day) because I walk everywhere and I teach preschool. Then I had to restrict my diet to no more than 3000 a day across four meals, and I got down to around 95. I'm now in the process of further readjusting my eating habits to get to and stay at 90 kg (which is a healthy weight for my size according to the US military).

When I was 110, I was technically exercising more than now (even doing with the same amount of activity) because I was hauling around an extra 15 kg. This meant that I would have needed to eat more if I had wanted to stay at that weight -- but it's kind of a chicken-and-egg scenario (I weighed 110 because of I had a big appetite) and losing weight has not decreased my appetite (it may have lowered the bottom threshold how much I need to eat before I can sleep or not feel hangry, but I'm literally always ready to eat and have been compared to a bloodhound when it comes to noticing fried foods). Ian.thomson (talk) 23:45, 11 April 2020 (UTC)

Thanks all, question is not about how the guy got fat, but rather, now that he is fat, is it likely that he is eating more than he used to? He is not under any restrictions or attempting to diet, and his diet is absolutely horrible, tons of fat and sugar. Plus he watches cable news all the time, which has to also be fattening. 2601:648:8202:96B0:E0CB:579B:1F5:84ED (talk) 03:58, 12 April 2020 (UTC)

Obese people have more fat cells, which produce ghrelin leptin, an appetite-suppressor. So this gives a negative feedback loop. For the same tasks requiring physical exertion, such as climbing up stairs, overweight people expand more energy, so to keep their weight they have to increase their caloric intake. However, they tend to avoid such tasks like by not taking long walks or taking the elevator. A third factor is that the stomach of someone who regularly overeats grows larger, thus is stretched less when eating and produces the sensation of satiety later. This gives a positive feedback loop. (Several bariatric surgery procedures for treating obesity aim at reducing stomach volume.) As noted above, different people are different, and the balance of these effects may be different for different people. I've known people with a voracious appetite and a sedentary lifestyle who nevertheless remained thin. In the literature cases are described of patients with extreme obesity who failed to lose weight in spite of a strict diet with severely restricted caloric intake. So the answer may be 'yes' for one specific individual, and 'no' for the next one.  --Lambiam 06:52, 12 April 2020 (UTC)

Thanks, that makes sense, that there's a mix of factors. The guy isn't at Santa Claus or Chris Christie levels of obesity (yet) but he has a noticable belly paunch and is probably overweight by 10 or 20 kg. Oh well. 2601:648:8202:96B0:E0CB:579B:1F5:84ED (talk) 07:17, 12 April 2020 (UTC)

For me, it is really simple. Or they eat more, or they consume less. If you eat, lets say, 3000 calories a day, but you don't do any exercise, you will gain weight, and fat. If you eat the same, but at the same time you do a lot of exercise, then you might lose weight, and fat. It is a thermodynamic thing. Then, besides exercise, you have a consumption of calories by just staying alive, and that depends on sex, age, and genetics. Some think that genetics is the most important factor. For me it isn't. Spend some time with someone really fat. Keep an eye how often they eat, normally, junk food. They usally have some food with them, some chocolate bars, soft drinks... In fact, you will see them eating all the time! So that's the main reason. They are like addicts to food. Niksfish (talk) 08:18, 12 April 2020 (UTC)

This assumes that all excess calories (intake minus energy expended) are stored in the form of fat. But is that true for everyone? Also, the body can adjust the metabolic rate to adapt to a dietary change.  --Lambiam 09:08, 12 April 2020 (UTC)

Indeed, and the healthier you eat the better the body will be able to make such adjustments. Also, if the weight of an overweight person is stable, then the person is actually burning as many calories as the person is eating. So, after any future weight loss the person should be able to eat exactly the same amount when replacing the burden of having to carry the excess weight by exercise. Note here that the metabolic activity of the fat tissue itself is quite low. But in practice people tend to gain back their old weight if after dieting, they revert back to their old eating habits even if they exercise a lot. This is because the body has a set-point for the amount of fat reserves. After weight loss the fat cells are emptier, so the body is then going to fill the fat cells again by adjusting the metabolic rate to be slightly below the calorie consumption. Thing is that animals could never have survived without such a mechanism. The body must adjust the metabolic rate to the calorie intake top prevent starving to death due to a very small deficit in the energy balance over long enough periods. Count Iblis (talk) 11:51, 12 April 2020 (UTC)

• The question should really be asked in two ways... "If one person eats more than they are now, will they likely gain more weight" and "If I eat more than you, will I become fatter?" The answer to both is "It's too simple a question to answer definitively", but the first scenario is more likely to be answered in the affirmative; generally with all other things being equal, a person who increases their caloric intake will increase their weight, and visa-versa; however there are all SORTS of other factors to consider in weight gain, and even that's not a 100%-always-true statement. The second scenario; by comparing caloric intake of two different people, is almost entirely unable to answer since people may have a plethora of different genetic and lifestyle differences, making person-to-person caloric recommendations in a general sense is basically impossible to answer. You can find specific overweight people who may very well consume less food than another specific underweight person; dietary recommendations are based on an "average person", but there are a stupidly large number of people who are not "average" and dietary needs are highly individualized.Here is the dietary guidelines from the World Health Organization. --Jayron32 14:37, 13 April 2020 (UTC)

• Jayron32, sorry about late response but I just saw your 13 April post. I really didn't intend my question in either of those two ways. I meant: there's a guy who is not living under food scarcity, so he has always been able to eat whenever he is hungry. I.e. his caloric intake is controlled by his appetite. Up til a few years ago his weight was fairly steady, so his caloric input was probably also steady, at let's say X calories per day. Since then, he has gained about 20 kg. His caloric intake is now Y calories per day for some Y. My question is whether weight gain, per se, is likely to increase a person's appetite so that Y is greater than X. E.g. if your weight and appetite are steady, but then one day someone performs "inverse liposuction" surgery to make you 20kg heavier, will that also increase your appetite? The answer appears to be indeterminate (based on above discussion), but I wanted to make it clearer what the question was. Fwiw. 2601:648:8202:96B0:E0CB:579B:1F5:84ED (talk) 22:48, 18 April 2020 (UTC)