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September 1

epidemiology of Covid19 in United States

Supposing there were a vaccine created for Covid-19 in the next few years, but only 40% of Americans took it, maybe because of genuinely harmful side effects, or pseudoscience, or whatever. Would the fraction of Americans who had been infected from Covid at least once eventually approach 60%, assuming the vaccine was almost 100% effective?Rich (talk) 07:48, 1 September 2020 (UTC)

That's not how herd immunity works. Somewhat simplified, if R0 is around 3 (which it seems to be for COVID-19), then every patient infects 3 others in a "virgin" population. If 2/3rds of people are immune for any reason, then that patient will only infect one other - the other two "transmission opportunities" fall on fallow ground. In that case, the number of infected will not grow (and if the number of immunes increases further, which it will naturally, each patient will infect less than one new case, and the number of new infections will go down exponentially). That's why basic herd immunity is computed as 1/R0. So you need 40% of vaccinated people, plus 26.6% of other immunes (i.e. people who recovered from infection). And if you manage to decrease actual R by other means (masks, social distancing, quarantine, ...) you may get away with even fewer cases. All this is assuming that recovered COVID patients are largely immune - something that seems likely, but we are not quite sure of. --Stephan Schulz (talk) 08:44, 1 September 2020 (UTC)

A relevant term here is "herd immunity threshold" (HT), which is the fraction of the population that needs to be immune for an infectious disease to push the effective reproduction number below 1. HT equals 1 – 1/R₀, the complement of 1/R₀. It is usually expressed as a percentage, so if R₀ ≈ 3, HT is about 67%. There are a few documented cases of recovered patients who were re-infected. The immunity conferred by vaccines does not last forever either, which is why some experts are warning COVID-19 may perhaps never be eradicated completely.  --Lambiam 09:46, 1 September 2020 (UTC)

• Notice that even though the infected population goes down once the immune population reaches 1-1/R (whether by vaccination or going through the disease) the epidemic will still infect a few people while dying down, so the eventually-infected population is higher than 1-1/R-vaccinated. For the gory mathematical details (under certain assumptions etc.), see the $r_{\infty }$ in Compartmental_models_in_epidemiology#The_SIR_model (the model does not include vaccination during the epidemic but I would conjecture the answer is not too wrong if you take $r_{0}$ as the proportion of vaccinated). Tigraan^{Click here to contact me} 12:54, 1 September 2020 (UTC)

Deer and goat hybrid is possible?

I've heard it's written in Mishna that it's possible but I'm not sure if it reflects reality or science. --ThePupil (talk) 12:26, 1 September 2020 (UTC)

It could be possible, but i wouldn't bet on it. Deer and goats are in different families, (Cervidae,Moschidae,Tragulidae) for deer and Bovidae for goats, so the cross would be an Interfamial hybrid. Zindor (talk) 12:43, 1 September 2020 (UTC)

It's very unlikely, given how rare interfamilial hybrids are. Most hybrids can only occur within the same genus, and I can't think of an interfamilial hybrid in mammals. List of genetic hybrids has none listed. --Jayron32 12:47, 1 September 2020 (UTC)

Thanks. Just want to note that Horses and donkies are also from different families, and still we may see the results exist as mules or hinnies.--ThePupil (talk) 14:59, 1 September 2020 (UTC)

They are absolutely not from different families. Horses and donkeys are both from the same genus even, Equus. As I said, there are no examples I can think of for viable mammal hybrids from different families. There may be some from different genera, but even so, the vast majority are different species within the same genus. --Jayron32 15:07, 1 September 2020 (UTC)

I thought they are different, because of what I read on this article on Wikipedia: "Donkeys have 62 chromosomes, horses have 64 chromosomes, and mules or hinnies have 63 chromosomes". So they are from the same family with a different number of chromosomes? --ThePupil (talk) 15:19, 1 September 2020 (UTC)

Yes, the number of chromosomes is not necessarily consistent between species even if they are in the same genus. In the case of horses and donkeys, they are both members of the same genus, being Equus. Family is one layer yet again higher up the Linnean classification system above genus. So everything that is part of the same genus is also part of the same family (and class, and order, and phylum, etc) --Jayron32 15:42, 1 September 2020 (UTC)

Thank you. I've learnt something new. So basically we cannot say surely that cross between deer and goat can be. Right? Do we know an animal hybrid of two families?--ThePupil (talk) 19:52, 1 September 2020 (UTC)

No, no one in history has ever produced a cross between a deer and a goat. You are incorrect on that. Deer and goats are members of entirely different families, deer being members of the Cervidae family and goats are members of the Bovidae family. Given that, as I noted above, there has not ever been before a mammalian hybrid from such distantly related animals, it is unlikely there to ever be one in the future either. --Jayron32 12:13, 2 September 2020 (UTC)

Some wild horses also have a different number of chromosomes. Ruslik_Zero 18:48, 1 September 2020 (UTC)

Deer-cow Hybrids seems somewhat controversial. Alansplodge (talk) 11:45, 4 September 2020 (UTC)

Do carrot tops contain toxic alkaloids?

The section § Consumption of the Wikipedia article on carrots states that "some sources suggest that the greens contain toxic alkaloids", citing two sources. Maybe I am overlooking something, but I cannot find this claim in either source. Is there some scientific basis for this – other than that almost any vegetable contains trace amounts of alkaloids?  --Lambiam 15:05, 1 September 2020 (UTC)

Some possible additional sources can be found here. This source here states that the alkaloids in question are pyrrolidine and daucine. --Jayron32 15:10, 1 September 2020 (UTC)

So "all alkaloids are bad because substances like caffeine and cocaine are alkaloids".^[1] Next thing you know people will start snorting carrot tops instead of smoking banana peels.  --Lambiam 07:37, 2 September 2020 (UTC)

I'm afraid I said nothing of the sort. I'm not sure where you think I did? --Jayron32 14:43, 2 September 2020 (UTC)

Lambiam wasn't quoting you, but rather the piece from carrotmuseum. Even there it was described as a "myth".

I'm curious now what "daucine" is. I don't see any recent entries on a naive search. "The Plant Alkaloids", by Thomas Anderson Henry, whoever he may be or have been, says the following, in a typeface that suggests it's a rather old book:

Carrot leaves contain, according to Pictet and Court, pyrrolidine and an alkaloid, DAUCINE, C₁₁H₁₈N₂. The latter is a colourless oily liquid, b.p. 240^o–250^o, [a]_D +7.74^o in ether, having an odour like that of nicotine, but which does not give the pyrrole reaction.

No structural formula is given. My guess would be that this substance now has a different name, which is why I don't find recent info on it, but I don't know what it would be. If it could be found, we should create a redirect. --Trovatore (talk) 17:44, 2 September 2020 (UTC)

SciFinder lists that name as having CAS# 1399-02-6 with a matching molecular formula and approximate boiling point (corrected from a different pressure), but no structure or other synonyms. DMacks (talk) 03:38, 3 September 2020 (UTC)

Thanks. Seems to be behind a paywall with no obvious price list :-) --Trovatore (talk) 05:54, 3 September 2020 (UTC)

This chemicals list, volume A–G of a two-volume book, has "daucine" as the only name for [1399-02-6]. The number does not occur in the H–Z volume, so it seems that there is no current synonym and that the dearth of results is due to its lack of popularity.  --Lambiam 07:18, 3 September 2020 (UTC)

The name undoubtedly derives from the genus name of the binomial name of the carrot, Daucus carota.  --Lambiam 07:31, 3 September 2020 (UTC)

The Dictionary of Food Compounds gives structural descriptions where known, but has for daucine: "Struct. unknown".  --Lambiam 07:41, 3 September 2020 (UTC)

This is the publication where Pictet & Court announce a novel alkaloid and name it daucine.  --Lambiam 08:37, 3 September 2020 (UTC)

That's cool. Fun to look at this old stuff sometimes. I'm a little shocked that no grad student has bothered to work out the structure in all these years. Could be a master's thesis, maybe? --Trovatore (talk) 18:20, 3 September 2020 (UTC)

It was a direct quote from the carrotmuseum page – the top result of the Google search. While it mentions "This popular myth", presumably (the antecedent is not made explicit) referring to the idea that carrot tips are not edible, the bit I quoted about caffeine and cocaine is in a different section and not identified there as being questionable.  --Lambiam 07:08, 3 September 2020 (UTC)

Ah. I think this was the page I saw, or possibly a mirror of it. It says Myth #1: Carrot greens contain alkaloids (which are toxic bitter compounds produced by a plant) and all alkaloids are bad because substances like caffeine and cocaine are alkaloids. Looks like it was directly quoting, and attempting to refute, the carrotmuseum line. --Trovatore (talk) 07:16, 3 September 2020 (UTC)

September 2

Why do mice like peanut butter so much and where did the cheese thing come from?

Does it have the right percent of macronutrients to survive on as little as possible or something? Is it missing any mousie essential nutrients? Do they still need water if they only have fresh peanut butter that hasn't lost water yet? Would they eat it till they're obese if they could? Or even gorge till they puke? Or just stop when they're not hungry? Do they hide some for later like squirrels? Sagittarian Milky Way (talk) 02:36, 2 September 2020 (UTC)

According to this article (cited in our article on the house mouse), rodents can't actually vomit. PaleCloudedWhite (talk) 07:55, 2 September 2020 (UTC)

A quick Google search indicates that peanut butter is rich in nutrients that mice crave. We used to bait our mouse traps with a tiny dab of the stuff, or sometimes a tiny bit of bacon could also do the trick. ←Baseball Bugs ^{What's up, Doc?} carrots→ 09:10, 2 September 2020 (UTC)

As to where the mice and cheese meme originates, in The Taill of the Uponlandis Mous and the Burges Mous of 1480, the town mouse dines on delicacies unknown to the country mouse; "chies and butter" get the first mention [2]. To be fair, they also eat candle wax, so perhaps it's the fat content - candles were made of tallow in those days "a rendered form of beef or mutton fat". Peanut butter wasn't invented until 1884, whereas both mice and cheese have been part of the human experience for millennia. Alansplodge (talk) 16:59, 2 September 2020 (UTC)

Dictionaire Oeconomique, Or, The Family Dictionary (1729) p. 128: "MOUSE; a little four footed Animal, so common and so universally, known as to need no Description... [they] are injurious in and about Houses, by eating Cheese, Meat, and other Provisions of the Houshold". Alansplodge (talk) 17:11, 2 September 2020 (UTC)

I recall reading somewhere that the association of mice and cheese comes from pre-20th century Western culture, where cheese was one of the foods that would be commonly found stored in a pantry. Remember, no refrigeration. It said mice don't have any real preference for the stuff, but they're omnivores and will eat what they can get. Flour and similar things can't be easily eaten by rodents because they can't bite them into chunks with their incisors. --47.146.63.87 (talk) 22:09, 3 September 2020 (UTC)

So what's the smallest crumb they'll eat? Will they eat crumbs past the point they start looking for bigger if they have no other choice? Perhaps by licking and swallowing whole? Sagittarian Milky Way (talk) 01:58, 4 September 2020 (UTC)

I'm not sure about that last statement:

"Mice can cause a surprising amount of damage in a cupboard or pantry, eating their way through flour, cookies, rice, beans, noodles and even meat contained inside pouches such as tuna or chicken. Dry soup mixes add flavor to the mouse's diet and cake mixes provide desert". What Do Mice Eat

"Generally speaking, mice are unlikely to get into your fridge or freezer. But if you have bags of flour or sugar or foods in cardboard boxes taking up space in your pantry, now is the time to stock up on airtight plastic or glass containers, according to Terminix" Things that attract mice

Not from authoritative sources, but opinions anyway. Alansplodge (talk) 11:44, 5 September 2020 (UTC)

Universe density without expansion

Could it be argued theoretically that without accelerating expansion of the Universe its density might gradually (possibly over some long period) increase (due to various matter-forming and shedding processes) to the point of becoming high enough to conduct sound waves? And is that acceleration actually essential to offset possible density increase which otherwise may overtake "slower" expansion, without acceleration? Brandmeister^talk 14:40, 2 September 2020 (UTC)

Matter-energy can't be formed. Expansion without any accelerating magic decelerates and will expand forever, stop on infinity AD or stop before infinity AD and go back to infinite* density. Probably tiny gray areas where outcome depends on quantum fluctuations too. Sagittarian Milky Way (talk) 14:57, 2 September 2020 (UTC)

I mean increase in gaseous density in particular, because various astrophysical processes generate gases, like hydrogen and oxygen. Presumably without accelerating expansion this continuous buildup of gases and molecules would affect average density of the Universe, making the space more dense. Brandmeister^talk 18:21, 2 September 2020 (UTC)

I'm not aware of any astrophysical processes that result in a net production of hydrogen - theoretically, Hawking radiation might occasionally produce a proton or electron around a black hole, but that would be (at least over normal cosmological time scales) be more than balanced by hydrogen falling into black holes. Oxygen is produced by stellar nucleosynthesis, but at the cost of using up much larger amounts of hydrogen. Typically, interstellar gas goes down as galaxies age (it's used up in star formation). --Stephan Schulz (talk) 19:57, 2 September 2020 (UTC)

Supernovae explosions, for example, are known to produce some elements (and reportedly, shock waves that compress gas clouds to aid new star formation). This raises an additional issue of possibly insufficient space for new stars and cluttering in the absence of Universe's expansion. Wow... unless there's something wrong with that assumption. Brandmeister^talk 20:42, 2 September 2020 (UTC)

Supernova explosions produce some elements, but not from nothing. They just rearrange existing matter into new configurations. Also, after a supernova explosion, there usually is one star less. --Stephan Schulz (talk) 20:53, 2 September 2020 (UTC)

But what about my question per se? Would the density increase without accelerated expansion? Brandmeister^talk 08:06, 3 September 2020 (UTC)

Matter & energy isn't being created or destroyed. If the size of the universe was held fixed, the overall mass density would be constant. That said, the local mass density can change, especially as gravity causes clouds of hydrogen and helium to condense into stars. The stars are very dense, but the surrounding area is then somewhat depleted. Stars convert hydrogen and helium into heavier elements. Over time the amount of hydrogen and helium will decrease and the amount of heavier atoms will increase. The total number of atoms is likely decreasing. Certain esoteric particles, such as neutrinos, are probably accumulating over time (however, their overall density will still be very low). Dragons flight (talk) 10:20, 3 September 2020 (UTC)

Still, there is conversion of energy into mass per energy-mass equivalence. Would it contribute to the density increase in a fixed-sized Universe? A supernova explosion shoots elements and debris into space. Supernovae explode relatively rarely while new stars are formed continuously in the entire universe. Apparently, for every single supernova explosion at least several new stars emerge - which may be another issue in a fixed-size universe. Brandmeister^talk 11:40, 3 September 2020 (UTC)

No, there isn't. Mass-energy equivalence means that energy already has mass. Everything else being equal, an object will weigh (very slightly) more when it hot than when it is cold because the thermal energy contributes (very slightly) to the total mass. You can convert energy into matter, but you haven't actually changed the total mass. Dragons flight (talk) 13:30, 3 September 2020 (UTC)

I'm reminded of the now discredited steady-state model which had matter created to fill the void created by expansion of the universe. Remove the expansion, keep the creation of matter and you're all set.

Steady state is dumb. It expanded from immense density and possibly bounces forever is simpler. Bouncing forever was later ruled by expanding forever of course. Sagittarian Milky Way (talk) 16:06, 3 September 2020 (UTC)

It appears dumb now, because we've latterly found evidence supporting a different model. That evidence hadn't been discovered when Steady State was first proposed by Fred Hoyle, at which Time Steady State was, if anything, a slightly simpler and seemingly more plausible model than what he derisively called "Big Bang". {The poster formerly known as 87.81.230.195} 2.122.2.158 (talk) 22:46, 3 September 2020 (UTC)

September 3

valved n95 respirators

It's still very hard to get unvalved n95 respirators, but valved ones (not recommended for virus protection because the exhaust port spews virus if you are infected) are getting easier to find. Home Depot near here has some. 1) Does snipping out the valve and patching the hole with a rubber seal sound like a reasonable fix to this issue? The seal would probably be a bit of cut-up nitrile glove hot-glued into the mask. From the picture I think the hole would be maybe 15mm diameter. 2) Why after all this time are regular n95 still so hard to get? There's no toilet paper shortage any more, for example. Thanks. 2601:648:8202:96B0:0:0:0:DDAF (talk) 05:47, 3 September 2020 (UTC)

I once ordered and wore a valved N95 (FFP2 in the EU) mask during pandemic. The valve there is for a reason, presumably otherwise they would not be certified as N95 (FFP2). My understanding is that "spewing" is negligible compared to the issue of heating and excess moisture buildup in a valveless mask (particularly in hot summer). Any custom modification of a N95 mask may breach its integrity and resistance. Brandmeister^talk 08:19, 3 September 2020 (UTC)

• For (2), the comparison does not make much sense. Toilet paper shortages were due to (a) panic buying resulting in a build-up of stock among consumers, (b) a change in the products consumed (toilet paper bought by companies, theaters etc. is not the same product as bought by private individuals). (a) takes care of itself within a few weeks because the demand spike is followed by a demand gap, (b) can be fixed by a (supposedly easy) retooling of existing machinery. On the other hand, the demand for masks has increased dramatically since February/March and will remain at a higher-than-before level for quite some time; it is not easy to expand production ten-fold at short notice, even with big price incentives. Tigraan^{Click here to contact me} 08:45, 3 September 2020 (UTC)
• Most studies indicate such valved masks are not terrible in spreading the virus, as long as the valves are properly used. This is just one example of many articles on the subject. The valved mask is not as good as the full N-95, but it is, within error bars, comparable to, and in some cases better than, things like cotton masks and surgical masks. In short: The valved mask is not as good as the full N-95, but neither does it "spew virus", and it is comparable to the wide range of other kinds of masks on the market, and much better than things like bandanas and T-shirt material buffs. If you can't get the fitted N-95, the valved one may be among your next best options. --Jayron32 11:47, 3 September 2020 (UTC)

Why is surgery done with only surgical masks? Sagittarian Milky Way (talk) 15:57, 3 September 2020 (UTC)

Sometimes they also use surgical knives.  --Lambiam 21:13, 3 September 2020 (UTC)

It gets worse, i've heard some rogues even wear surgical gloves! Zindor (talk) 21:46, 3 September 2020 (UTC)

Some of them also wear surgical stockings. {The poster formerly known as 87.81.230.195} 2.122.2.158 (talk) 22:49, 3 September 2020 (UTC)

So why is it okay to do surgery with only a fancy cloth on your face but corona nurses need gas mask-looking things? Sagittarian Milky Way (talk) 01:49, 4 September 2020 (UTC)

I suspect your premise is flawed. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:50, 4 September 2020 (UTC)

It looks like a serious question. Face masks during the COVID-19 pandemic is a good start to learn about the various masks. Medical prophylactic practices have to strike a balance between efficiency (protection against contamination by a given pathogen), cost, and side effects (a hazmat suit will block all pathogens, but it would be unwieldy to perform chirurgy from inside one); it is not surprising that the best option for a given context might not be best for another context. You should also note that handling yourself around an operating room requires nontrivial training ("operating room training" returns a bazillion hits for certification programs), so it seems possible to me (OR warning) that stringent procedures compensate for lower-protection equipment. Tigraan^{Click here to contact me} 15:22, 4 September 2020 (UTC)

Chemistry, Nitrogen and it's compounds form three

How is nitrogen gas prepared ? — Preceding unsigned comment added by Emmanuel ngetich (talk • contribs) 17:58, 3 September 2020 (UTC)

Mostly by taking it from the air, of which it is the overwhelmingly major constituent. The air separation article describes the major processes for doing it. DMacks (talk) 18:08, 3 September 2020 (UTC)

Though, pertaining to the section title, nitrogen compounds are rarely if ever prepared from nitrogen gas, because the dinitrogen triple bond is very strong and takes a lot of energy to break apart. Instead, ammonia or other nitrogen compounds are used as the nitrogen source. Ammonia is produced today with the Haber–Bosch process, one of the most important inventions of the 20th century and a major industrial process. --47.146.63.87 (talk) 22:14, 3 September 2020 (UTC)

Which of course it is important to note that the Haber-Bosch process uses nitrogen derived from the air as it's feedstock, so ultimately most industrially-derived sources of nitrogen compounds do indeed come from nitrogen in the air. Before the Haber-Bosch process, nitrogenous compounds were primarily obtains through old-fashioned biosynthetic means: we used plants and animals to produce them, and we got it from there. This includes things like guano deposits (basically bird shit and bat shit) and nitrogen-fixing microorganisms in the soil and plant roots known as Diazotrophs. Bird shit used to be so important to the world economy that global conflicts have been started over access to it. See Guano Islands Act, Chincha Islands War, War of the Pacific, etc. all of which were significantly about control of guano. The Haber-Bosch process changed a lot of that. --Jayron32 15:22, 4 September 2020 (UTC)

Right, Haber–Bosch catalyzes the breaking of the dinitrogen bond so it can be done at scale. Non-synthetic nitrogen compounds get their nitrogen ultimately from nitrogen fixation by microbes, which have nitrogenase enzymes that accomplish the same trick. --47.146.63.87 (talk) 02:11, 5 September 2020 (UTC)

September 4

Covid?

This is regarding someone who died recently from as-yet unannounced causes. You can probably figure out who, but the question is about the illness rather than the person, so I omit his name. A news article said:

"However, [person] posted on Twitter in August that he had “been sick for a month.” He maintained that the illness caused him “z exhaustion, stomach [and] lung-ache.”

He was up and about until a few days ago, then entered hospital and died rather quickly. Do those symptoms sound like covid, or anything else particularly? Thanks. 2601:648:8202:96B0:0:0:0:DDAF (talk) 08:57, 4 September 2020 (UTC)

Per the instructions at the top of the page "We don't answer requests for opinions, predictions or debate." This would require respondants to give opinions about whether or not the patient in question had Covid. No one here examined that patient. Instead, if you want to form your own opinion, you can read Coronavirus disease 2019#Signs and symptoms. --Jayron32 14:40, 4 September 2020 (UTC)

Not a diagnosis and hardly an opinion, but each of these symptoms has been reported for COVID-19. Each individually could have any number of causes.  --Lambiam 14:50, 4 September 2020 (UTC)

The OP is capable of reading the linked article and learning that themselves. He doesn't need us to tell him that. --Jayron32 15:12, 4 September 2020 (UTC)

• Notice that "disease X causes set of symptoms Y with high probability" does not entail "symptom set Y is caused by disease X in most (or even many) cases". It is therefore not sufficient to know whether someone's symptoms are compatible with a given disease to deduce that they likely have that disease. For instance, blue mucus is a symptom of infection by Pseudomonas aeruginosa, but blue mucus reports are likely to be caused by hallucinogen abuse (source (fr)). Tigraan^{Click here to contact me} 15:33, 4 September 2020 (UTC)

[Damn, it's no longer possible to recover an unsaved edit from an edit conflict, so I have to rewrite this response]. I carefully tried to not make this about the patient, but rather about whether those symptoms match what has been observed about Covid and other possible causes. That's not a matter of speculation, but of trying to identify Bayesian priors, grounded in sources (maybe indirectly) if you like to think of it that way. E.g. this mentions toxins as a cause of soapy taste in the mouth, suggesting he was exposed to something, while "lung-ache" immediately evokes covid. "Speculation" on the other hand would be e.g. "maybe Putin poisoned him with Novichok".

Note that Wikipedia's treatment of this type of topic is almost useless, because MEDRS makes it exclude an enormous amount of sourcing that a reasonable person would consider informative. I mentioned that the person is dead to make it clear that this is not about a medical decision. Plus, a Covid article would say nothing about other possible causes.

Anyway, stop freaking out. We have a big article about possible causes of the death of Mozart since how Mozart died is still uncertain centuries later. What's left is to match up Mozart's symptoms with possible causes, as that article shows is a perfectly reasonable thing to do. The only thing really different about the case I'm thinking about is that it is much more recent. 2601:648:8202:96B0:0:0:0:DDAF (talk) 15:52, 4 September 2020 (UTC)

No one has freaked out. What people have done is told you where to find the answer to your question. That's what we do here: tell people where to find answers to their questions. If you have more questions, please ask them, and we will tell you where to find those answers. --Jayron32 16:21, 4 September 2020 (UTC)

You mischaracterized a reasonable factual question (what identifiable causes do these symptoms match) with "request for opinions, speculation, or debate". I consider that response to be freaking out. I rather carefully constructed the question to avoid the issues that trigger some people here (medical advice => nope, the person is dead; BLP/BDP => avoided naming the deceased person, etc.) but you seem to have gotten triggered anyway. Obviously the cause of death can't be identified with certainty with the info available (at least as of yesterday) but I'm not seeking certainty. As the Mozart article shows, it's perfectly reasonable to look for informative priors even though reaching anything like certainty is impossible. That's all I'm trying to do here. I really don't understand what set you off. It's certainly a less consequential question (since the guy is dead) than "what could cause my washing machine to make a squealing noise during its spin cycle" (might be a belt, might be a problem with the motor, etc.) and nobody would complain about that question here, I hope. 2601:648:8202:96B0:0:0:0:DDAF (talk) 16:38, 4 September 2020 (UTC)

Also, "people" did not tell me where to find answers. You are the only one who did that, in an unhelpful and bureaucratic way. Two other regulars, Lambiam and Tigraan, gave actual useful answers, for which I thank them. (Tigraan's answer was basically advice to beware of confounders when reasoning about conditional probability and causation, something we all have to be reminded of sometimes). 2601:648:8202:96B0:0:0:0:DDAF (talk) 17:35, 4 September 2020 (UTC)

In case there's some confusion, BLP including BDP apply to living persons and recently deceased regardless of whether you "avoid naming them" when it's extremely obvious who you are referring to. The question of what level of obviousness may be debated, but if you were to open a discussion at WP:BLP/N I'm sure you'll find this affirmed. Otherwise I could sat "according to my contacts, the president of X is a paedophile who enjoys raping kids" (where I specify X), and it's fine since I didn't actually name the person. That's clearly nonsense. If you want to try and argue semantics that "president of X" is equivalent to naming them, you could easily substitute world leader who talked about injecting disinfectants, world leader actively promoting Covid-Organics, former world leader who said "we don't have homosexuals, like in your country" etc.

P.S. As a further example of why your question was so incredibly flawed, you seem to have completely ignored that person you're referring to also said they tested negative in response to a question about COVID at the time of the post you referred to. You also ignored the fact the post referred to a tooth infection and root canal. Such details are surely important when considering the symptoms but of course are difficult to consider when we are analysing random parts of someone's post where you think avoiding mentioning their name or directly linking to them somehow gets around BLP concerns. If you didn't mention such details because they weren't explicitly mentioned in whatever RS you read, that again, the obvious question is why it matters unless you too recognise that there are indeed still BDP concerns. (I think it also raises the question of how reliable this source actually if is they would neglect to mention such details.)

Nil Einne (talk) 08:09, 6 September 2020 (UTC)

There is a difference between article space, like the Mozart article, and reference desk space, where we are now, and different rules apply to those different spaces. We have specific rules against answering the type of question you have asked here. In an article space, with proper reliable sources (rather than speculation of editors), something could be said (in conjunction with rules regarding biographical articles). Not here, though. --OuroborosCobra (talk) 18:20, 4 September 2020 (UTC)

The question was "Do those symptoms sound like covid, or anything else particularly?" and why should it be forbidden to answer something like "No, they don't. If 'exhaustion, stomach [and] lung-ache' are compatible with covid, they are also compatible with a lot of other things. But so far as I know "beeing sick for a month" is not compatible with covid, which if it kills it does so in one to two weeks. And beside that several common symptoms are missing in the description like high fever, headache and insistent cough, which would have probably been mentioned had they been present." ? 2003:F5:6F00:ED00:D3A:2C30:3941:92C6 (talk) 14:57, 8 September 2020 (UTC) Marco PB

River proximity and groundwater levels

Am I right in thinking that groundwater levels are higher the closer the place is to a river bank? Would that mean that dams reduce groundwater levels downstream by making rivers smaller? Is there any place I can read more about this? Wikipedia does not provide answers, unfortunately. Surtsicna (talk) 22:51, 4 September 2020 (UTC)

Usually the water table is higher than a river, and there will be springs and seepage coming into the river. However in a desert, you could expect the water table to be lower, and that the river recharges the water table. However if much of that happens the river will dry up. A dam will likely raise the water table around the dam, but since a dam is designed to retain water, it should not be in a place where much water leaks out. Graeme Bartlett (talk) 23:49, 4 September 2020 (UTC)

And if you aren't busy, Geological structure as a control on floodplain groundwater dynamics tells all. Alansplodge (talk) 11:33, 5 September 2020 (UTC)

September 6

Brown bear vs. human

I read that brown bear species (Ursus arctos) is divided into sixteen subspecies, due to morphological/genetical differences and habitat. My question is: from a strict biological perspective, would be ncecessary to divide humans (Homo sapiens) into subspecies, again due to morphological/genetical differences? Notice that I reject the social construct of "race", any kind of racial discrimination, the concept of one "race" being "superior" or "inferior", racial laws and historical definitions such as "Nordic race", Mediterranean race" and so on. I know that dividing humans into three or five or seven "subspecies" is not the same of brown bears, but I read biological differences exist and that's what I ask. Thanks in advance.--Carnby (talk) 07:51, 6 September 2020 (UTC)

Looking at Subspecies, I don't think it applies to humans. ←Baseball Bugs ^{What's up, Doc?} carrots→ 08:36, 6 September 2020 (UTC)

[Edit Conflict] The current consensus is that all living humans are members either of the species Homo sapiens which has no recognised subspecies, or of the single subspecies Homo sapiens sapiens, most often contrasted with the now extinct sister subspecies Homo sapiens idaltu.

Neanderthals have sometimes been classified as the subspecies H. sapiens neanderthalensis and sometimes as the species H. neanderthalensis: Denisovans have not yet been given a formal taxonomic status to my knowledge (which may well be outdated), as too little physical material representing them has been identified: one could argue for them being part of H.Neanderthalensis, a subspecies "H. neanderthalensis denisova", "H. sapiens denisova", or something else. The problem is that in biology there is no objective agreement on exact definitions of and distinctions between species and subspecies: different definitions (over 30 for "species") are used in different contexts. At least one prominent paleoanthropologist has expressed the opinion that there has never been more than one human species extant at any one time, given the evident willingness of various named 'varieties' of humans to interbreed when the opportunity arose.

There is also a model currently emerging within paleoanthropology of African Homo sapiens being an amalgam of several African regional populations somewhat physically and genetically differentiated through temporary geographical isolation prior to their subsequent re-merging, before their subsequent interbreeding outside of Africa with Neanderthals, Denisovans and possibly other groups as yet unknown.

Given the potentially fraught outcomes that might result from defining any living human population as a different subspecies from the rest of humanity, I suspect that all responsible scientists are very unlikely to discuss even the theoretical possibility of doing so. {The poster formerly known as 87.81.230.195} 2.122.2.158 (talk) 08:59, 6 September 2020 (UTC)

I echo the explanation by I.P above. Also you might find our article on Homo floresiensis interesting, who were described as the 'hobbit' people. Populations in the Nazca region and beyond (Easter Island) may have possibly been influenced by the Paracas culture; who are theorized as having naturally elongated skulls that predated and influenced Artificial cranial deformation. That's all a bit fringe though, and isn't well-covered on Wikipedia. Zindor (talk) 09:38, 6 September 2020 (UTC)

Correct me if I'm wrong but didn't I read somewhere that human races are more genetically similar to each other than different parts of an animal subspecies' range? Cause genetic mixing caused by humans exploring and falling in love or lust. Presumably in low tech eras the skin colors and nose shapes wouldn't mix quite as much as other genes as they were slowly selected by the sunlight and temperature of where they originated. So the races have mixed more than racists think. Also they like to show that Equatorial Guinea has the lowest IQ and don't say it was a small country where the crazy dictator killed anyone who might be smart and even anyone with glasses and they were the Dachau of Africa for awhile with massive population loss and brain drain from purges and people braving the minefields and boat ban to flee. Sagittarian Milky Way (talk) 13:53, 6 September 2020 (UTC)

Squirrels are able to produce subspecies. Potatoes are able to produce cultivars. Is H. Sapiens indeed the only magical life form totally unable to produce subspecies? I strongly suspect this is a very dangerous question to utter. People have been cancelled for far lesser crimes than asking this question. Tread carefully, as you are walking on politically correct eggshells here. 85.76.78.82 (talk) 16:57, 6 September 2020 (UTC)

Read what it is that causes subspecies, and it should become clear why humans don't qualify. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:29, 6 September 2020 (UTC)

We're all awfully closely related for a species with our numbers. Probably mostly due to recent bottlenecks, only a few thousand generations, in evolutionary times. There's a concept in population biology which I can't remember the name of - being the size of the population you would guess from a given amount of genetic variation. Well, humans have the genetic variability you would expect in a species of 100,000 or so, not billions. If that's missing from our relevant articles, it is probably because they were written by humans. :-)John Z (talk) 06:20, 7 September 2020 (UTC)

I think the answer to my question is this (from subspecies): "The variation among individuals is noticeable and follows a pattern, but there are no clear dividing lines among separate groups: they fade imperceptibly into one another. Such clinal variation always indicates substantial gene flow among the apparently separate groups that make up the population(s). Populations that have a steady, substantial gene flow among them are likely to represent a monotypic species, even when a fair degree of genetic variation is obvious."--Carnby (talk) 11:25, 7 September 2020 (UTC)

If a convenient asteroid is modeled as x% gold and platinum atoms and the rest rubbish how high does x need to be to mine it soon?

All mixed together homogenously.Sagittarian Milky Way (talk) 13:18, 6 September 2020 (UTC)

Gold and platinum are native metals so i would imagine they'd be available fairly easily in their elemental form. I'm assuming the 'rubbish' would be carbonaceous chondrite such as found in a C-type asteroid. How to deal with that chemically i don't know, it might be easier to physically mine it. Zindor (talk) 13:34, 6 September 2020 (UTC)

So when I hear of people mining rocks with invisible gold content it just means the easy stuff is gone and they're scraping the bottom of barrel. So I might find gold nuggets walking around (jetpacking around?) a NEO and just pick them up? Sagittarian Milky Way (talk) 14:04, 6 September 2020 (UTC)

I doubt they'd exist alone as a sizeable nugget, as space debris would be constantly wearing away at them. As far as i'm aware, these companies mining precious metals out of low% sediment do turn over a profit. I'd suggest that panning in a river for nuggets might be a more viable option that jetpacking around an NEO. Zindor (talk) 14:24, 6 September 2020 (UTC)

Of course they make profit or they wouldn't do it, I'm wondering how many percent you'd need to scoop up the regolith or whatever and choose which atoms you want to take (maybe vibrating the grains in a centrifuge and taking the dense ones?) and still make profit. No one can be sure an asteroid is profitable without going there probably so it'd be a very expensive risk. Maybe one of our tech billionaires will try one day lol. And one wonders who gets to mine where if other billionaire(s) suddenly want to try the same asteroid if the first one makes high profit. Sagittarian Milky Way (talk) 15:37, 6 September 2020 (UTC)

Mineral/precious metal deposit speculation is a real business and sometimes money gets thrown at non-profitable mining projects, keeping it afloat, in the hope that they 'strike gold/the motherload' so-to-speak. The key is to invest early, let uninformed investors pile in and raise the share price, then sell your shares just before the project goes bust. It'll be a free-for-all once humanity gets into space; the UN Space Treaty that currently exists will just be ignored for sure. Zindor (talk) 20:19, 6 September 2020 (UTC)

• Our page asteroid mining cites [3] which does more or less that calculation. It assumes 150ppm platinum (0.015%) and would be deemed too unprofitable for the amount of risk taken. It also assumes between 700 and 70,000 tonnes of platinum are hauled back to Earth; the lower figure is already four times the yearly Earthly production (see [4], table 4) so it seems probable that the market price of platinum would decrease significantly if such a project happened (whereas the article assumes a fixed price). Tigraan^{Click here to contact me} 09:38, 7 September 2020 (UTC)

A genetic cause for sex height differences?

Is there a genetic cause for height differences between men and women? Futurist110 (talk) 21:33, 6 September 2020 (UTC)

See Sexual dimorphism in primates, Sexual dimorphism in non-human primates. Zindor (talk) 21:59, 6 September 2020 (UTC)

Puberty covers it. The pubertal "growth spurt" is both initiated and terminated by rising estradiol levels. After the onset of puberty, males have lower levels than females, so they generally start the "growth spurt" later, and it lasts longer, resulting in greater average adult height. --47.146.63.87 (talk) 04:47, 8 September 2020 (UTC)

September 7

Iguanas and snakes: Where was this filmed? What type of iguana and snake?

This YouTube BBC video [5] shows some type of iguanas and snakes, which are not identified. However, there is a longer clip from the original programme, which was broadcast on France 2, and has a complete voice-over narration, in French. I cannot understand spoken French, so I wonder if anyone here can do so, or otherwise identify the species of reptiles being filmed, and the location. I am not sure if it is allowed to post the second YouTube clip here, on WP. It can be found on YouTube by searching for "iguane vs serpents" and choosing the "ZAPPING SAUVAGE" clip, which runs for 5:13 minutes. Absolutely amazing! And if you like wildlife videos, well-worth the five minutes. (A secondary question...would a link to the second video be allowed here? I wished to err on the side of safety, and not post the link.) Thanks, Tribe of Tiger ^{Let's Purrfect!} 21:34, 7 September 2020 (UTC)

You can turn on English subtitles. However the clip does not say where or exactly what animals these are. Someone in the comments also asked exactly your questions without answer. Graeme Bartlett (talk) 00:29, 8 September 2020 (UTC)

The BBC site says this is Galapagos Islands.[6] Graeme Bartlett (talk) 01:24, 8 September 2020 (UTC)

The animals are Amblyrhynchus cristatus and Galapagos racer. Graeme Bartlett (talk) 01:25, 8 September 2020 (UTC)

@Graeme Bartlett: I did not know about the option for English subtitles, will try this. For some reason, I thought about the Galapagos, based on the volcanic terrain. Lucky guess! I will look at/follow your BBC link, so that in future, I can find such information for myself. Thanks so much for answering my question, and also for describing your method of obtaining it. You are a helpful editor and a good educator. Best wishes, Tribe of Tiger ^{Let's Purrfect!} 03:19, 8 September 2020 (UTC)

@Graeme Bartlett: I see that our WP article on the Galapagos racer has a reference to this excellent video. Because the terrain seemed so barren, I wondered how the iguanas found food...and WP provides the answer! Thanks again, Tribe of Tiger ^{Let's Purrfect!} 03:34, 8 September 2020 (UTC)