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April 10

Do flu symptoms get worse late at night?

Is there a tendency for flu symptoms, such as nasal discharge, to get worse late at night? Freeknowledgecreator (talk) 05:21, 10 April 2020 (UTC)[reply]

This is known to be the case for the common cold and many other diseases; see this article in the Daily Mail. I do not know if this has been specifically observed for influenza too, but it would be more surprising if that illness was the exception. --Lambiam 06:06, 10 April 2020 (UTC)[reply]

I would also be interested in hearing whether COVID-19 symptoms get worse late at night. Freeknowledgecreator (talk) 06:38, 10 April 2020 (UTC)[reply]

The human immune system has a circadian rhythm (I assume all mammals are the same). Therefore, regardless of the trigger for the immune system, it becomes more effective at night. Much of the symtoms we feel, such as a fever, are caused by the activity of the immune system. So, you feel worse at night. Serach for "human immune system circadian rhythm" and you will find resources. 97.82.165.112 (talk) 10:54, 10 April 2020 (UTC)[reply]

For what it's worth, incredibly anecdotally, my COVID19 symptoms were worse at night. However, despite contacting my town board of health, doctor's office, and state department of health, at the time I was sick, the test criteria were so strict and the test available so non-existent that I was never tested. --OuroborosCobra (talk) 00:19, 11 April 2020 (UTC)[reply]

Will see you at Alpha Centauri

Coronovirus opened up a possibility to read the NYT without subscription, so I got there and saw an article: (April 7, 2020) Deceleration of Interstellar Spacecraft Utilizing Antimatter. It turned out to be an old news. Last year it appeared in Scientific American: August 5, 2019 [1], there are even earlier publications[2]. Article in NYT is the most interesting but I cannot reference it for obvious reason, please go there and read it. All you need is to give them your email. The shock begins at the moment you read the title (above).

This is a NASA Project. They already got some funding! The paper says: "Antimatter-based propulsion and power has emerged as a leading technology capable of enabling science missions to the exoplanet Proxima b. In stark contrast to other mission proposals involving beamed energy, this mission assumes prompt and continuous science return during the entire voyage, deceleration at Proxima Centauri," The craft is supposed to achieve ultimately 10% of the speed of light. It will be a small spacecraft, as the paper says: ten kilogramscale. The mission will begin in 2069 and last 40 years one way. A laser will be used to send messages back to earth. If they plan to decelerate it with antimatter, why not accelerate it the same way also?

Where are they going to get the antimatter? Is it realistic? To make some, the craft needs to be equipped with a particle accelerator, then perhaps a few atoms they will produced. There is no antimatter in our visible Universe. Is it just a joke?

Thanks, - AboutFace 22 (talk) 22:32, 10 April 2020 (UTC)[reply]

@AboutFace 22: According to the article Antimatter, it is naturally occuring (in addition to coming out of particle accelerators in small amounts). RudolfRed (talk) 23:37, 10 April 2020 (UTC)[reply]

(edit conflict) Antimatter propulsion is the general concept. A core problem with space travel is there's no friction in space. It takes energy to slow down just as much as to speed up. And if that's not bad enough, there are no gas stations either. Unless you can get the energy for stopping from somewhere, you have to carry it with you as some kind of fuel, which then takes more energy to accelerate at the beginning, which takes more fuel, and you can see where this is going. This is known as the "tyranny of the rocket equation". Envision driving cross-continent but towing all your fuel for the trip. This is why Breakthrough Starshot envisions a flyby—they just won't bother stopping! What you mention seems to envision accelerating the craft similarly, like with a beamed light sail, and then carrying antimatter as fuel for the stopping part. The nice thing about antimatter is it stores a lot of energy. The bad thing is storing it, since it reacts with ordinary matter. We can create it on demand in particle accelerators, as you note. Doing so is just expensive, so there's no point doing it to power your car. Some antimatter gets produced more or less continuously, mostly positrons, but it gets destroyed quickly because it finds some ordinary matter and annihilates. That's why we need special containment systems. But we inject people with antimatter-generating compounds all the time! Pretty nifty huh? --47.146.63.87 (talk) 23:48, 10 April 2020 (UTC)[reply]

Here's a link to the highly speculative article on the NASA TV website. I see no evidence that this idea has received funding from NASA, and the hypothetical destination is a planet around Proxima Centauri not Alpha Centauri. The Scientific American article does discuss efforts by astronomers to observe possible planets around Alpha Centauri, but I could find no discussion of interstellar spacecraft or antimatter. I am a New York Times subscriber and have searched their website every which way I can, and found no article about this topic. Of course, they have published articles about antimatter, and about interstellar travel, and have mentioned those two stars in various ways but none of those articles that I could find make the connection implied, and they were all published years or decades ago. So, something is fishy here. Can you explain, AboutFace 22? Cullen³²⁸ Let's discuss it 00:19, 11 April 2020 (UTC)[reply]

Proxima Centauri is (believed to be) part of Alpha Centauri, so that's not an error. See its article. --76.71.6.31 (talk) 02:20, 11 April 2020 (UTC)[reply]

Proxima Centauri is a red dwarf star which is located about .21 light years away from the Alpha Centauri binary star. That is an enormous distance away, and is about 5% of its distance from our solar system. Cullen³²⁸ Let's discuss it 02:32, 11 April 2020 (UTC)[reply]

True, but so is what I said. --76.71.6.31 (talk) 19:04, 11 April 2020 (UTC)[reply]

Well, I feel my honor is at stake. I don't subscribe to NYT for two reasons: too much to read with my subscription for WSJ and also I am not a liberal and spiritually it is hostile source for me, but the free access was an opportunity. I copied the paper. I have nice database for that. It is now in front of me. Probably, I found the funding mentioning in a different source, I could not find anything about it at NASA website [3]. I remember they have been given $17M with the stipulation that there will be no more funding, that they need to find rich private donors. I think it is a highly speculative idea to begin with. Tomorrow I will find the article in the NYT. I am surprised you could not. Just google their website. Thanks, AboutFace 22 There is also this[4] (talk) 02:29, 11 April 2020 (UTC)[reply]

Even if no one makes a trip to Proxima Centauri, it would be useful to be able to produce anti-matter cheaply, and to be able to store large amounts of it, and convert it into electricity or movement. Fast trips around the Solar System could become possible. If you need to have a large amount of energy in a device, but never recharge it, then this is for you. Graeme Bartlett (talk) 03:54, 11 April 2020 (UTC)[reply]

More on antimatter: how much it costs, etc. [5] AboutFace 22 (talk) 13:51, 11 April 2020 (UTC)[reply]

Compress matter to a miniature black hole. This will then evaporate by Hawking radiation, the late stages of this Hawking radiation will contain electrons and positrons. You then feed this black hole with matter to prevent it from vanishing. On the long term you can then harvest vast amounts of antimatter at very low costs. Count Iblis (talk) 15:00, 11 April 2020 (UTC)[reply]

Black hole starship --47.146.63.87 (talk) 02:57, 12 April 2020 (UTC)[reply]

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)[reply]

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)[reply]

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

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

What constitutes a colonial organism?

In relation to the recent discovery of a clonal, colony organism (a Siphonophore). The article I read is short[6], 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)[reply]

I thought the biggest single organism was supposed to be a fungus covering 2000+ acres in Oregon.[7] We have an article Largest organisms listing other possibilities. 2601:648:8202:96B0:E0CB:579B:1F5:84ED (talk) 04:53, 11 April 2020 (UTC)[reply]

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

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 [8]. ~~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)[reply]

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

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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

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[reply]

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)[reply]

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[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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

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

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)[reply]

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)[reply]

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)[reply]

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

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)[reply]

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)[reply]

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

(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 [9] [10] [11] [12] [13]. 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. [14] [15] [16] [17] While broadly, they seem to support what many countries have done e.g.[18], 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 [19], 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 [20], 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)[reply]

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 [21] [22]. 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)[reply]

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)[reply]

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)[reply]

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

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)[reply]

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.^{[23] (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.^[24] 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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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 [25] [26] [27]. 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 [28].) 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)[reply]

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)[reply]

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

“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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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

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)[reply]

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)[reply]

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)[reply]

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

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)[reply]

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

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)[reply]

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)[reply]

@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)[reply]

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)[reply]

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)[reply]

@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)[reply]

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. --Jayron 32 14:26, 13 April 2020 (UTC)[reply]

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)[reply]

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. --Jayron 32 12:34, 15 April 2020 (UTC)[reply]

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)[reply]

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 ([29] [30] [31]). 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 ([32] [33] [34]).

(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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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. --Jayron 32 14:37, 13 April 2020 (UTC)[reply]

April 12

What were those satellites?

This morning my mum saw 19 satellites going over in rapid succession. We are in France in the Charente-Maritime, and they were in the southern sky heading south-east. Does anyone know what they might have been, or what resources there are out there that would identify them? (checking satflare but I can't find them) At first I thought "Starlink!" but it's been a while since the last launch and I don't think they would still be together in such a culster. Maybe though. — PhilHibbs | talk 09:52, 12 April 2020 (UTC)[reply]

They're not spreading out as fast as you might think. See Starlink Train 3, launched way back at the end of January. Their leading group is still quite bunched. They would have passed over the area you described about an hour ago -- but that was well after your sighting, so it may have been a different train. What time was the observation?

Also note that 34 OneWeb satellites were launched on 21 March, six days before the company entered bankruptcy. I'm not sure how visible they are, but they're a possibility worth investigating.

I haven't figured how to pull up data on past passes from satflare.com, so please post something if you do. -- ToE 11:24, 12 April 2020 (UTC)[reply]

I've figured out how to use satflare and the first was probably Starlink 1316, the timing (06:10 local time, 04:10 UTC) is spot on. — PhilHibbs | talk 12:19, 12 April 2020 (UTC)[reply]

Cool! So that is what they are calling Starlink Train 5, launched 18 March 2020. I now see that in the "Live Sky Chart" section, it explains using the [s]/[S], [m]/[M], [h]/[H], [d]/[D] keys to adjust the time offset and see past passes, both there and in the Map View. -- ToE 13:01, 12 April 2020 (UTC)[reply]

Virus Movie

Virology

I have produced a short video (≈ 5´) on the basics of viral development. It is planned to publish the video in one of the articles associated with the topic, provided it is reviewed positively by qualified WP peers. The file format is .ogg, the file size may be 50MB.
As I am not a virologist / biologist I want to ask wikipedians of relevant biomedical knowledge for a review. Please point out any errors and suggest improvements where suitable.
Thank you to anybody who finds time to evaluate the movie! --Cookatoo.ergo.ZooM (talk) 16:00, 12 April 2020 (UTC)[reply]

Cookatoo.ergo.ZooM, you may want to repeat this at Wikipedia talk:WikiProject Viruses or Wikipedia talk:WikiProject Microbiology, as you're more likely to find someone who knows what they're talking about there. Alansplodge (talk) 18:22, 12 April 2020 (UTC)[reply]

Re-reading that post, I might have been a bit unfair to my fellow Reference Desk regulars; please accept my apologies if you do know what you're talking about. Alansplodge (talk) 18:35, 12 April 2020 (UTC)[reply]

I am not a virologist or even a biologist, but possibly more like a typical member of your intended audience. I'm afraid that the information density at this rate of presentation is far more than can be absorbed, for each of the channels: the spoken text, the texts displayed, and the visuals – and even more so for all this combined. As to the visuals, it is not always clear how what you see relates to what is being said, and also not what various symbolic representations (such as the "glass marbles") stand for. My advise would be to leave a lot of the less essential stuff out ("less is more"). Organization-wise, I think that after an initial teaser to get the attention ( ending for example in a "cliff hanger" sentence like "So how does a virus multiply?"), a bottom-up organization would work better: cells, RNA/DNA, proteins, protein synthesis, virus morphology, virus structure, virus modus operandi. Finally, IMO the music should be less loud, particularly so while text is being spoken. Oh, and I'd say /ˈnu.kli.əˌtaɪd/, not /nuˈkli.ə.taɪd/. --Lambiam 20:09, 12 April 2020 (UTC)[reply]

I haven't watched it yet (will do so when I'm in an environment where I can watch a video), but if it's intended for wikipedia, please keep it informational and get rid of any entertainment elements such as music or cliffhangers. They are just annoying. We aren't trying to generate clicks or sell ads here. The purpose of a video here should be to efficiently communicate info that can't easily be conveyed in text. 2601:648:8202:96B0:E0CB:579B:1F5:84ED (talk) 20:31, 12 April 2020 (UTC)[reply]

The voice-over sounds computer generated and does not pronounce some things clearly or even correctly. Also the background is fairly cluttered. It would be better to show just the one thing at a time in the images, synchronised with the narration. The scrolling text is hard to read while narration is in progress. I think it would be clearer to just pop up the key words as they are said, but not have them scrolling on the screen. And keep the music away from the narration. Graeme Bartlett (talk) 00:14, 13 April 2020 (UTC)[reply]

OP here:

I appreciate these comments. This is still WIP / work-in-progress and fine-tuning / reorganising the story board will deal with the critique expressed.
Re narration; The voice over was computer generated and pronunciation is inconsistent / partly incorrect. I will replace it with a natural voice.
Re structure: 1: Virion (general introduction, RNA / DNA, proteins) - 2: viral entry - 3: genome replication - 4: protein synthesis - 5: assembly - 6: exocytosis. Each take (some 60”) will be organised similarly, starting with a 20” movie. Then follows a freeze frame (40”) with narration, synchronised labels and blue/green screen overlays showing associated details.
Re clutter: I plan to concentrate on sparse essentials and delete redundant visual (and audial) junk. Some of the information (where too specific) will be dropped. Music will be removed from the video. I agree that the current information density is excessive.
Re synchronisation of images, narration and text: I was aware of some irritating misfits of content in the channels. --Cookatoo.ergo.ZooM (talk) 13:37, 13 April 2020 (UTC)[reply]

Video maker Cookatoo.ergo.ZooM follows earlier videos about Synapse and DNA Replication in similar style, which might be better suited to a TV commercial than to Wikipedia. An introduction to a complex subject works better where there is an effort to serve information in simply defined contexts (the purpose of subheadings in Wikipedia articles) rather than immersing the viewer throughout in details and nomenclature. Color is a powerful tool when applied selectively for focus in a diagram but when every one of many objects is a shiny primary color we get a garish impression like a plate full of M&M's. In reality one will never see chocolate in all those colors, just as microscopic virus and cell materials are rarely seen in color, unless deliberately stained. I suggest restraining the over-use of title fonts. The soothing music doesn't help in correlating the images, scrolling text and relentless Australian(?) robot voice that all compete for attention. DroneB (talk) 15:18, 13 April 2020 (UTC)[reply]

Please delete my clear name from your posting. It has no relevance. --Cookatoo.ergo.ZooM (talk) 15:49, 13 April 2020 (UTC)[reply]

Done. Please DroneB (and everyone) remember to refer to WP users by their chosen WP identities. DMacks (talk) 16:17, 13 April 2020 (UTC)[reply]

April 13

Is Homeopathy recognized by American, European governments

There are many homeopathy doctors in India. There are some doctors who say it cannot be trusted. — Preceding unsigned comment added by 42.110.196.161 (talk) 11:26, 13 April 2020 (UTC)[reply]

In the UK homeopathy used to be provided through the NHS. In general that is no longer the case - see here. Mikenorton (talk) 11:47, 13 April 2020 (UTC)[reply]

Does the article Regulation and prevalence of homeopathy answer your questions? --ColinFine (talk) 13:09, 13 April 2020 (UTC)[reply]

It's definitely recognized in America and Europe, as Quackery. ←Baseball Bugs ^{What's up, Doc?} carrots→ 14:36, 13 April 2020 (UTC)[reply]

In the UK and USA, "homeopathy" is water (or sometimes something similar, like crystals). I have worked with doctors from India. They describe "homeopathy" as modern medicine mixed with classical remedies, such as herbs. Therefore, it is possible that this question is mixing up two radically different forms of medical treatment that use the same name. 97.82.165.112 (talk) 19:29, 14 April 2020 (UTC)[reply]

I think homeopathy is sometimes used loosely by those who don't understand what it is, but AFAICT, there is no difference in what homeopathy means in India except that it is possibly more likely to be mixed with other treatments like ayurvedic or naturopathic ones and I think the concept of "like cures like" is sometimes ignored. See these Indian government sites [35] [36] [37]. Note that although the last ones has "mother tinctures" AFAICT, these are intended to be diluted before homeopathic use. See also [38]. And maybe [39] which notes that a number of the "drugs" are imported from Germany (somewhat ironic since India is a major manufacturer of real pharmaceuticals). BTW, as clear from those links, homeopathy is still regulated and supported by the Indian government in some fashion. And before people laugh at how "backwards third world countries", remember that as per our articles and [40], the UK's NHS and Spain only removed funding recently, in France it's is only going to be phased out in 2021. And Germany is an interesting case, our articles may lead you to believe it no longer funded. But it sounds like it often is see the earlier external link and [41] [42] [43] [44]. The relative amounts may be low, but remember the "drugs"/"medicines" should basically cost almost nothing to produce so it's almost pure profit for the manufacturers etc and the "doctors" (who I gather are sometimes real doctors as well) get money for doing nothing really. Nil Einne (talk) 21:48, 14 April 2020 (UTC)[reply]

Can coronavirus be spread from humans to parrots?

Specifically my goffin.

I'm healthy, as far as I'm aware at this point. But in general, could she get the virus from being close to me if I had it? — Preceding unsigned comment added by 146.200.127.203 (talk) 13:04, 13 April 2020 (UTC)[reply]

Some coronaviruses can. Remember that when you say coronavirus you're referring to a huge, diverse classification of viruses; it would not be unlike asking "Can mammals do XYZ". If you are referring to the specific coronavirus causing the current pandemic, known as Severe acute respiratory syndrome coronavirus 2 or "SARS-CoV-2" (name of the virus species) and Coronavirus disease 2019 or "COVID-19" (the disease caused by that specific species of virus), then the answer is "we don't know". here is what the CDC in the United States says, in summation "Animals get coronaviruses, but we don't know much about if they can catch THIS coronavirus, and even if they can, what effect it will have on them". This article discusses human-to-animal transmissions we know about already, as does This one, but I don't see anything specific to birds. Consider this answer as "Humanity hasn't figured out if it can or cannot yet" and not "it cannot". --Jayron 32 14:21, 13 April 2020 (UTC)[reply]

Here is something that specifically discusses birds. --Lambiam 14:27, 13 April 2020 (UTC)[reply]

Best not to keep bats and pangolins as pets. Count Iblis (talk) 19:43, 13 April 2020 (UTC)[reply]

April 14

Mechanism of hydrogen absorption by palladium

Why exactly is palladium so good at absorbing hydrogen? Nickel and platinum are in the same group, and they certainly are not. Double sharp (talk) 16:28, 14 April 2020 (UTC)[reply]

This is a rather old paper and highly technical, but may be a good start. This is a newer and more accessible synopsis article, which may be closer to helping answer the question; in summation there's something specific in the crystal lattice of the palladium metal that allows H2 to efficiently adsorb onto the palladium that metal atoms of different metallic radius or crystal shapes would not work as well. --Jayron 32 19:53, 14 April 2020 (UTC)[reply]

That first ref notes that nickel does take up hydrogen, but that the amount is more limited for the bulk metal because of poor penetration below the surface. Might be some useful info to add to the nickel hydride article? Nickel is at least good enough for use in some hydrogenation catalysts, so please be careful with a blanket statement that nickel is not good at it. Doi:10.1016/j.ijhydene.2006.07.004 discusses use of nickel as a hydrogen-storage material. I found that last ref by google-scholar search for [adsorption of hydrogen onto nickel]. DMacks (talk) 23:45, 14 April 2020 (UTC)[reply]

Well, yes, what I meant was that Ni was certainly not as good as Pd at this. ;)

Hmm. Jayron32's comment about metallic radius and crystal structure prompted me to check other similar metals. Palladium has a metallic radius of 137 pm and has an fcc crystal structure; well, platinum is 138.5 pm and also fcc. But apparently platinum is not good at absorbing hydrogen, even under pressure. It looks like rhodium is the second-best platinum metal at doing this, but RhH_x is thermodynamically unstable. (Well, it is also fcc and 134 pm, so not far away.) So it must really be very sensitive to small changes. Double sharp (talk) 03:43, 15 April 2020 (UTC)[reply]

Anything relevant in a comparison of reduction potentials, thinking about forming an alloy with more M–H bonding than just an inclusion in the M structure? Doi:10.1039/B701402C is an experimental analysis of the structural changes of Pt (and Au) upon absorption of H2. DMacks (talk) 08:33, 15 April 2020 (UTC)[reply]

I just want to clarify that it isn't just the metallic radius and crystal lattice to the exclusion of all other possible factors which can explain palladium's properties here. There are probably dozens of properties relevant to our discussion (coordination number, electron affinity, electron configuration, reduction potential, atomic mass, spin-spin coupling, etc. etc. etc., along with many others I either can't think of or are too bored to list) each of which adds a non-trivial contribution to palladium's particular properties, causing it to hit that perfect sweet spot in terms of hydrogen adsorption. The fact that I found articles that highlighted those particular properties should in no way imply that the answer to the question was a simple as that, and that one could ignore everything else. --Jayron 32 12:20, 15 April 2020 (UTC)[reply]

April 15

A single coronovirus

Many years ago while on a lecture for Infectious Diseases in the Medical School our professor said that there were only 4 infections which were able to cause the infectious agent to multiply and cause a clinical disease if only a single bacterium / parasite entered the body. Anthrax chiseled in my memory, but I forgot the other three. I wonder if the coronovirus can infect you via a single agent? Thanks, AboutFace 22 (talk) 01:01, 15 April 2020 (UTC)[reply]

While I do not know the answer, a better question may be what the probability is that a single SARS-COV-2 virion will lead to a detectable infection. It appears that at least for Baculovirus viruses, which infect butterflies, a single virion may lead to infection.^[45] For the influenza A virus, the probability that a single virion entering a cell will successfully replicate is very low, but not zero.^[46] Extrapolating from these cases, I think that it is likely that, likewise, this probability is non-zero for the various coronavirus species. --Lambiam 08:25, 15 April 2020 (UTC)[reply]

Basic reproduction number (R₀) seems relevant. 107.15.157.44 (talk) 09:35, 15 April 2020 (UTC)[reply]

No - that refers to how many people are infected by a single case - nothing to do with how many virus particles entered the body.--Phil Holmes (talk) 11:35, 15 April 2020 (UTC)[reply]

I would be shocked if measles wasn't on that list; it is extremely infectious. However, I would urge caution in any kind of simple list like that; whether X germs will trigger a disease is not going to be the same number for all people at all times of their lives in all circumstances. Matt Deres (talk) 14:44, 15 April 2020 (UTC)[reply]

In principle, it seems like any virus could potentially cause an infection from a single virion. ~~It's not like they have to collaborate inside the body.~~ It's just a question of whether the virion manages to find a cell to infect, and enough of its children do, and so on. As Lambiam says, the key question is how likely it is for this virus, and I really don't know the answer to that.

Another consideration is that an infection starting with a small number of virus particles takes more time to reach a high viral load, which may give the host's immune system more time to mount an adequate response. --Trovatore (talk) 19:47, 15 April 2020 (UTC)[reply]

I take it back — one of Lambiam's links above suggests that viruses do in fact collaborate inside the body, to fill out incomplete viral genomes. News to me. --Trovatore (talk) 21:14, 15 April 2020 (UTC)[reply]

Social distancing effect on other viruses

Does all this social distancing mean that other viruses will also be slower to spread such as common colds? 90.198.251.144 (talk) 14:19, 15 April 2020 (UTC)[reply]

This reference suggests that the answer is "yes". Which isn't surprising, given that methods of transmission (and prevention) are broadly similar. Washing your hands is a "good thing" for the prevention of many diseases. Matt Deres (talk) 14:46, 15 April 2020 (UTC)[reply]

The basic premises of germ theory would suggest that the answer is yes, as well, for almost any infection. Even if an infectious agent is truly airborne, the concentration of that agent will fall off as a factor of distance from someone infected (barring effects like wind), so even with an airborne infection, being 6 feet from other people vs 1 foot from other people will reduce infection rate. Same with bodily fluid transmissions, in so far as you are less likely to come into contact with blood from someone else if you are consciously staying 6 feet away from everyone. As for sexually transmitted diseases, I suppose that depends on whether individuals are likely to reduce their number of sexual partners while exercising social distancing, which I imagine will differ person to person and society to society. At a very basic level, social distancing is sort of a "quarantine lite," not quite as effective as a full on quarantine, but working on similar principles. --OuroborosCobra (talk) 19:09, 15 April 2020 (UTC)[reply]

Does this mean that in theory some viruses could be eradicated? Maybe the ones which weren’t that common to start with. 90.198.251.144 (talk) 09:45, 16 April 2020 (UTC)[reply]

Apart from samples kept in a few high-security research labs around the world, the viruses causing smallpox and rinderpest have been eradicated. See Eradication of infectious diseases. --Lambiam 15:28, 16 April 2020 (UTC)[reply]

Radio waves are not electromagnetic

In wikipedia articles on electromagnetic waves, Radio waves and Heinrich Rudolf Hertz it is stated or implied that Hertz has demonstrated that radio waves are electromagnetic. These articles are often accompanied by the diagram of the electromagnetic wave showing the magnetic and the electric component of the wave. Such a statement is not correct because Hertz has in fact detected his waves with the help of a loop of wire through electromagnetic induction, which means that he detected only the magnetic component of the wave. Thus Hertz had no means to detect the electric component. The authors of the wikipedia articles on the topics mentioned above need to refer the reader to the experiments (if any) that proved the existence of an electrical component in the radio wave.--2405:9800:BA00:3477:117:FE22:C3E0:C875 (talk) 20:13, 15 April 2020 (UTC)[reply]

Radio waves are absolutely electromagnetic, as are all parts of the electromagnetic spectrum. There is no functional physical distinction between phenomena such as light waves, radio waves, X-rays, gamma rays, etc. except that our human sense organs (eyes) are specifically tuned to react chemically to a specific narrow set of wavelengths in that spectrum. They are all electromagnetic waves. Uunderstanding that radio IS an electromagnetic wave really comes from Maxwell's equations, (which are probably more properly termed Heaviside's equations, but you know, we're stuck with existing nomenclature, see History of Maxwell's equations for more of the gory details) which establish the three-legged stool that is electricity, magnetism, and light as being all different manifestations of the same phenomenon. What Hertz did was to provide experimental verification of the relationship between what we now call "electromagnetic waves" (light more generally, including radio) and electromagnetism. Electricity and magnetism were already experimentally linked by Ørsted some decades before even Maxwell; Hertz therefore didn't also need to establish the connection between electricity and magnetism; by experimentally verifying Maxwell's connection between magnetism and light, he effectively united all three phenomena, and unlike your assertions, did not also need to establish the connection of magnetism to electricity. That was done at least 2 generations earlier. --Jayron 32 20:32, 15 April 2020 (UTC)[reply]

Also, besides James Clerk Maxwell, Hertz, and Oersted, you probably also want to look into the works of many other scientists to understand the many, many contributions to the field that led to our current understanding of electromagnetism and light. Oliver Heaviside, as noted above, provided us with our modern formulations of what we still call the Maxwell equations. Michael Faraday established the connection between magnetism and visible light, among many of his other contributions. André-Marie Ampère did additional experimentation based on Ørsted's earlier work. Charles-Augustin de Coulomb did some of the earliest work on connecting electricity and magnetism, noting the similar ways in which the two phenomena behaved, though he stopped short of recognizing them as physically connected in the way that later physicists did. Henry Cavendish also did some early work in the field that went into inspiring much of Maxwell's work. Joseph Larmor established the mathematical relationships between the motions of electrically charged particles and the emission of electromagnetic waves. There's probably dozens more you can read about at History of electromagnetic theory, those are just one's that I could think of off the top of my head. --Jayron 32 20:44, 15 April 2020 (UTC)[reply]

Click here for Hertz's experiments that confirmed Maxwell's prediction that coupled electric and magnetic fields could travel through space as an EM ("electromagnetic wave"). This was not a single experiment but a range of experiments that confirmed the reflection, polarization, refraction, standing wave and speed properties of the EM. The OP's denial of the EM's nature that mainstream science has understood for more than a century as "incorrect" is arrogant and the title of the OP's non-question is merely provocative. DroneB (talk) 12:23, 16 April 2020 (UTC)[reply]

Sadly, this sort of thing is a problem with the persistent Great Man history version of science that scientific progress occurs through the herculean efforts of a select few great men, who perform singular feats of scientific discovery that the entirety of human understanding turns on. Instead, scientific advancement happens rather incrementally through the gradual and persistent effort of thousands and thousands of people working both independently and in collaboration, and who we give "credit" to is largely a function of public relations and marketing more than actual importance. I mean, as I noted above, look at Maxwell's equations. Don't get me wrong, Maxwell was super important, but not nearly as important as "Single-handedly invented the modern formulation of electromagnetism in 4 simple equations". There were dozens of people both before Maxwell and after Maxwell that put in a TON of work in developing that formulation, and while convenient, it does a massive disservice to the complexity of the process to do that. That's why people think they can do what the OP did: "I found a mistake in the work of so-and-so, so that MUST bring down the entirety of what all of science thinks". No, it doesn't. Because even if you did find that mistake, we weren't hanging our understanding on one person, or on one event or experiment. And guess what, even if you did find that mistake, someone already found it before you and fixed it. Arrogant is correct, but in many ways that arrogance is the fault of our historiography of science more than anything, and we're still dealing with this silly Great Man thinking today. --Jayron 32 13:58, 16 April 2020 (UTC)[reply]

That was one of the main points of the TV series Connections, that everything we have invented built on previous things. Recently there was a show on PBS, I think it was, which exposed the fact that Leonardo DaVinci, who has almost a god-like reputation, had many entries in his notes which were copies of others' ideas. What DaVinci did in many cases was to improve upon those ideas. Kind of like guys such as Edison and Ford, whose main claim to fame was improving on things that often already existed in some form or another. And Edison, for example, didn't sit there all alone testing filaments until he found one that worked - he had a whole team working on it. ←Baseball Bugs ^{What's up, Doc?} carrots→ 14:23, 16 April 2020 (UTC)[reply]

Such a good show. Everything James Burke has done is fantastic. Love all of his work. --Jayron 32 14:35, 16 April 2020 (UTC)[reply]

The wisest of the philosophers was asked: "We admit that our predecessors were wiser than we. At the same time we criticize their comments, often rejecting them and claiming that the truth rests with us. How is this possible?" The wise philosopher responded: "Who sees further a dwarf or a giant? Surely a giant for his eyes are situated at a higher level than those of the dwarf. But if the dwarf is placed on the shoulders of the giant who sees further? ... So too we are dwarfs astride the shoulders of giants. We master their wisdom and move beyond it. Due to their wisdom we grow wise and are able to say all that we say, but not because we are greater than they. - Isaiah di Trani 1180 - 1250. Echoed by Isaac Newton in 1675: "If I have seen further it is by standing on the shoulders of Giants." DroneB (talk) 16:52, 16 April 2020 (UTC)[reply]

Sigh. Still not one of the above wikipedia editors is able to give a single reference to an experiment that detected the electric component of the so-called "electromagnetic" wave. So arrogant of me to ask a basic question required by the scientific method of investigation. Again, Hertz detected the waves with a loop of wire - that is through electromagnetic induction, so he detected only the magnetic component of the wave. And no one detected the electric component since then. This means that, as of today, radio waves are just magnetic waves. Which, incidentally, is what Stokes thought of Hughes' waves when he was called to investigate them 7 years before Hertz did his experiments. When you have the experimental evidence of the detection of the electric component of the "electromagnetic" wave, pls. let me know. Much appreciated. :)--Idnwiki (talk) 16:59, 16 April 2020 (UTC)[reply]

The unification of electricity and magnetism was first demonstrated by the experiments of Hans Christian Ørsted and shortly thereafter by André-Marie Ampère and Michael Faraday in the early 1800s. The work of James Clerk Maxwell established the geometric relationship between electric and magnetic waves that co-propagate orthogonally, and also established that these electromagnetic waves should be indistinguishable from light. Hertz's experiments established the connection between these co-propagating waves and light, specifically in the radio band, but radio is not a different phenomena than light (as shown by Oliver Lodge among many others), and Hertz's work was expanded on by the work of Jagadish Chandra Bose. Your question is nonsensical; asking how one would detect the "electrical component" as distinct from the "magnetic component" is like asking one to isolate the head of a coin from its tails. The two were inextricably linked via Maxwell et. al. and determined to be different manifestations of the same phenomenon, not individually isolatable phenomena. This was further demonstrated by the connections between special relativity and electromagnetism; which established that there is no reference frame that one can use to make consistent measurements of the electromagnetic force such that the "electric component" and "magnetic component" can be definitively isolated, and that really whether one observes the force as electrical or magnetic is really about which reference frame you choose to observe the phenomenon (see Lorentz force). You can see a pretty good explanation of this problem here or here. The ultimate point is; your question is nonsensical and by asking it you're showing a common misunderstanding of the nature of electromagnetism. We're trying to explain to you what that misunderstanding is, so you stop asking the nonsensical question. --Jayron 32 17:21, 16 April 2020 (UTC)[reply]

In simple terms: changes in the magnetic field strength induce an electric component. The laws determining the precise relationship are given by Maxwell's equations. They have been confirmed experimentally with high precision. But every working dynamo is an experimental confirmation of the existence of this relationship. It works two ways: an electromotor is essentially a dynamo working in reverse. In modern high-speed electric trains and in many hybrid cars (e.g. Tesla), the motors become dynamos when the vehicle is reducing speed, allowing to save energy by storing the electricity generated in batteries. A "magnetic wave" implies a varying magnetic field strength – otherwise it would not be a (moving) wave. Therefore the electric component is an unavoidable companion. --Lambiam 17:38, 16 April 2020 (UTC)[reply]

@Idnwiki You have been politely asked to stop posts at Talk:Electromagnetic_radiation such as [47] and [48] in which you demand to be given a proof just to satisfy you. However when you contend that there is no electric field in a radio wave the burden of proof is on you to explain how a microwave oven heats and why the ratio of the electromagnetic and electrostatic units of charge, 1/√ε₀μ₀ gives the speed of radio waves. DroneB (talk) 17:43, 16 April 2020 (UTC)[reply]

@Jayron32 In the reference frame in which the wave is produced, there are electric and magnetic fields that exist as such in and around the antenna and that can be detected through different methods and with different apparatus. What I get from you is only insults, attacks, not experimental proofs. It is nonsensical to know that the antenna had originally electric and magnetic fields and then say that in the wave produced these two become indistinguishable even if they are detected in the same reference frame as the transmitting antenna.--Idnwiki (talk) 17:48, 16 April 2020 (UTC)[reply]

@DroneB. Yes, I was asked that and so I did. And I was directed to ask further in this section. Still no meaninful answer, nothing new. All that you all 've been telling me I already know (and a little more than that). Now I am told by @Jayron32 that the electric and magnetic components of the "electromagnetic" wave are actually not distuishable any more. Thanks very much. Maybe you can explain then how the reception occurs in the receiving antenna. --Idnwiki (talk) 17:54, 16 April 2020 (UTC)[reply]

No one has insulted you. We've been trying to understand and to explain to you the misconceptions you seen to have that are leading you to the wrong conclusions. You've started by asking your question based on a premise that isn't a correct understanding. Simply put, we cannot answer your question as asked because it presumes certain things to be true that are not. I'm not sure what else we could do for you, you're trying to play "Gotcha" with 300 years of physics. That isn't how any of this works. You can either try to learn the physics (which will probably take quite a while is outside the scope of this desk) or you can accept that those thousands of scientists over those 350 years knew what they were doing. You've come up with some weird beliefs, and unless you are willing to dispossess yourself of those beliefs, and take learning physics with a dose of humility in deference to the people who did this work already, in not sure what else we can do. You aren't arguing with us, you're arguing with all of physics on this. --Jayron 32 18:27, 16 April 2020 (UTC)[reply]

If you would like an experimental demonstration, try your microwave oven. Most would consider the radiation from it to be "radio waves," since it is roughly the sam portion of the spectrum as wifi and bluetooth. That it heats water is due to the electric component of the radio wave electromagnetic radiation. The electric field component of the radiation is what interacts with the electric dipole moment of a given molecule (say, water) to induce rotational molecular motion. You can do this experiment yourself. This can occur in molecules without unpaired electrons in any orbitals, and thus cannot be explained by any type of paramagnetic properties alone. --OuroborosCobra (talk) 18:51, 16 April 2020 (UTC)[reply]

The article Antenna (radio) is a good place to start. The electric and magnetic field components are distinguishable and you have not been told otherwise. They are orthogonal in the propagating EM wave. The polarization of an antenna refers to the orientation of the electric field (E-plane) of the radio wave with respect to the Earth's surface. Of the many Antenna types let's take the Yagi–Uda antenna that is a common sight on house rooves where analog TV is broadcast. The element rods have to be horizontal or vertical to match the plane of the electric field from the local transmitter. DroneB (talk) 19:07, 16 April 2020 (UTC)[reply]

I think the problem is that when the OP isn't asking a question about how an electromagnetic wave interacts with antennas. They are asserting the rather nonsensical position that no experiment has ever been done that shown that the interactions between radio waves and antennas showing the existence of electric component of the electromagnetic wave, and then demanding we produce an experiment that proves them wrong. I'm growing weary of arguing with someone who comes seeking affirmation rather than information. --Jayron 32 19:59, 16 April 2020 (UTC)[reply]

I think I have read much more than what you wrote in your wikipedia article on Antenna (radio), including the references. And the arguments of "300 years" and of the "many scientists" and of "arguing with all of physics on this" (plus the virulent answers of some of you) do not scare me neither convince me. You should know that people are not discouraged by these methods of intimidation. Many people thought that airplanes cannot fly, in the phlogiston and many other nonsense in their times. Yagi antenna and any receiving antenna works through electromagnetic induction - a current is induced in the antenna by the magnetic component of the radio wave. The only plausible experimental proof of the existence of the electric component (which IS the thing I've been asking for from the beginning) seems to be microwaves/water system. I'll look into it, thanks. But the way some of you choose to treat someone posing a legitimate scientific question is disgusting and shameful. You know who you are.--Idnwiki (talk) 20:15, 16 April 2020 (UTC)[reply]

Well, you are what you've described, for one. --OuroborosCobra (talk) 20:29, 16 April 2020 (UTC)[reply]

I don't think it good form for me to box an exchange in which I have taken part and there have been excellent references in most of the responses here. However if an uninvolved editor decides to box this whole discussion that arose not from a question, more like an insubstantial complaint, that will put a tidy end to the matter. DroneB (talk) 21:17, 16 April 2020 (UTC)[reply]

Just for the record: wikipedia editors state that radio waves are electromagnetic. They show the electromagnetic wave having electric and magnetic components. Then someone (me) asks for proof that the electric component of the wave has been detected and for adding reference to such proof in articles. The wikipedia editors do not give any such proof but instead call the question "nonsensical", "arrogant" and "provocative", implying that the person asking the question needs to study more, although the issue raised is legitimate from the point of view of the rule sof scientific method of investigation.Typical.--Idnwiki (talk) 04:20, 17 April 2020 (UTC)[reply]

April 16

Aviation / ADS-B / which parameters are sent?

Hi! I believe, I heard in 2015, that todays airplanes transmit their intended flight level via radio frequencies, that everybody could "hear" and then decode. E. g.: The plane is at 30000ft and the pilot configures the flight computer to 20000ft and then the plane sends to the ground "<time stamp> <airline specific parameter id> <value>". Is it true? I cant find that in Automatic dependent surveillance – broadcast. Is it used now for quality assurance, so that pilots, who are too far off, win a flower pot, so that they can see how beautiful the world can be? Thx. Bye. --Homer Landskirty (talk) 14:39, 16 April 2020 (UTC)[reply]

ADSB (Automatic dependent surveillance – broadcast) sends a periodic message that provides actual position, velocity and time but, at present not pilot intent. DroneB (talk) 17:58, 16 April 2020 (UTC)[reply]

hmmm... ohoh... and ACARS? or was it fake news? they said FlightRadar24.com saw it, too... and that every airline uses its own id and scaling (e.g.: 0 meant 100ft for D-AIPX)... --Homer Landskirty (talk) 18:23, 16 April 2020 (UTC)[reply]

A few things have changed with respect to ADSB since 2015 - especially in the United States. Most prominently, the very-heavily-advertised January 1 2020 deadline has long passed; and nearly all aircraft in the United States National Airspace System now require operational ADS-B equipment when flying in "most controlled airspace". Those who need to know these things... should already know these things; and if they didn't get the memo yet, ... somebody with authority has almost surely found them by now.

Here's a few highlights from FAA's website:

Automatic Dependent Surveillance-Broadcast (ADS-B) - a general overview
Equip ADS-B - information for aircraft owners and operators
Information on ADS-B Capabilities
- ADS-B In and ADS-B Out, including TIS-B, FIS-B, ADS-R, and related technologies
- Resources, including easy links to the relevant regulations, TSOs, and technical papers; and statements of policy

Like many aspects of aerospace engineering, the technical details of the technology that we lump together as "ADS-B" can become quite complicated. So it's really important to think about formulating your question more specifically. Are you looking for engineering resources? Legal or regulatory guidance? Information for pilots? Information for mechanics? Information for aircraft owners? Information for aeronautical or engineering students? Information for HAM-radio enthusiasts? Information for people (pilots, operators, ...) who are not in the United States? ... There are a lot of different communities who have stake in this kind of thing - and while it's very thoroughly documented, it can be hard to navigate - so let us know if we can point you to a more appropriate source.

And if you're just looking to waste time while hanging around indoors, may I recommend that you take advantage of all this free-time to start memorizing the FARs in preparation for some future day when you might want to accomplish a checkride? I guarantee that no matter how much free time you have, there are enough FARs to fill them...

Nimur (talk) 18:24, 16 April 2020 (UTC)[reply]

actually i look for proof, that it is not my delusion, when i say, that those engineers at my university r insane... my psychiatrists always say, that i am insane, although they never even spoke with those engineers (one even told me that a professor warned him, not to be too radical, because radicals just hurt, if they get to much... he always intrigued and lied IMO...)... i mean: if they talk about engineers in general, then one example should be reason enough, to reconsider the diagnosis/medication they gave me... --Homer Landskirty (talk) 18:55, 16 April 2020 (UTC)[reply]

there r the findings of flightradar24: [49]... looks like they received the config of the autopilot... right? --Homer Landskirty (talk) 18:41, 16 April 2020 (UTC)[reply]

April 17

tele video on camera phone

for shooting video on camera phone, can the rear tele camera be used? reviews only discuss video on the main camera. this is on phones with a designated tele camera, like the Realme 6. thanks!

Most reviews on phones I read discuss both front and rear cameras. Certainly both can be used for video. --OuroborosCobra (talk) 02:00, 17 April 2020 (UTC)[reply]

Whitcomb rule for cars?

is the Porsche 911 GT1 designed according to Whitcomb rule? is it of any value at these speeds? thanks!

The Whitcomb area rule, also called the transonic area rule, is a design technique used to reduce an aircraft's drag at transonic and supersonic speeds, particularly between Mach 0.75 and 1.2 (575 to 920 mph, 926 to 1482 kph), see Area rule. A Porsche 911 GT3 manages at most "only" 193 mph (311 km/h) and the GT1 is slower, so No and No. DroneB (talk) 01:18, 17 April 2020 (UTC)[reply]

@@ Line 332: / Line 332: @@
 :::::::::::::::::::Well, you are what you've described, for one. --[[User:OuroborosCobra|OuroborosCobra]] ([[User talk:OuroborosCobra|talk]]) 20:29, 16 April 2020 (UTC)
 <small>I don't think it good form for me to box an exchange in which I have taken part and there have been excellent references in most of the responses here. However if an uninvolved editor decides to box this whole discussion that arose not from a question, more like an insubstantial complaint, that will put a tidy end to the matter. [[User:DroneB|DroneB]] ([[User talk:DroneB|talk]]) 21:17, 16 April 2020 (UTC)</small>
-:Just for the record: wikipedia editors state that radio waves are electromagnetic. They show the electromagnetic wave having electric and magnetic components. Then someone (me) asks for proof that the electric component of the wave has been detected and for adding reference to such proof in articles. The wikipedia editors do not give any such proof but instead call the question "nonsensical", "arrogant" and "provocative", implying that the person asking the question needs to study more. Typical.--[[User:Idnwiki|Idnwiki]] ([[User talk:Idnwiki|talk]]) 04:20, 17 April 2020 (UTC)
+:Just for the record: wikipedia editors state that radio waves are electromagnetic. They show the electromagnetic wave having electric and magnetic components. Then someone (me) asks for proof that the electric component of the wave has been detected and for adding reference to such proof in articles. The wikipedia editors do not give any such proof but instead call the question "nonsensical", "arrogant" and "provocative", implying that the person asking the question needs to study more, although the issue raised is legitimate from the point of view of the rule sof scientific method of investigation.Typical.--[[User:Idnwiki|Idnwiki]] ([[User talk:Idnwiki|talk]]) 04:20, 17 April 2020 (UTC)
 = April 16 =