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July 11
Long Covid and T cells
Is there any reliable evidence that Long COVID depletes/damages T cells? I have heard this assertion repeatedly, and seen some anecdotal evidence to suggest it might be true for some people. I don't know if there is any reliable peer reviewed evidence to support this claim, but the wiki article on Long Covid makes no metion of T cells anywhere.Uhooep (talk) 09:16, 11 July 2022 (UTC)
- First of all, it seems fairly well-established that the acute phase of covid-19 depletes T cells. (I could not tell from your post whether that fact is obvious or not to you.) See for instance T cell responses in patients with covid-19 by Chen&Werry, published in Nature Reviews Immunology in July 2020 (= forever ago in terms of covid-related-research), which says
One prominent feature of SARS-CoV-2 infection is lymphopenia
(i.e. depletion of lymphocyte cells).
- But the question is about long covid, and for that, the answer seems to be a resounding "maybe". From the highly scientific method of typing
"long covid" t cell
in Google Scholar and picking out the articles with the most cites, I found:
- [1], a review, puts out some evidence (§2.6) that lymphopenia causes long covid (rather than the other way around): patients with an underlying condition that causes lymphopenia will not recover well from covid. However, the author seems decided to pin the blame on Toxoplasma gondii without much consideration of other alternatives, so I have a feeling the paper might be a bit fringe-y (as in "pushing a minority opinion" fringe, not "earth is flat" fringe; it was still published in a good journal).
- [2], a primary study, describes a correlation (long covid patients have lymphopenia) but does not explain causation and invites further research into that area (which is boilerplate but I assume the authors have done their bibliography and know that there is a gap there)
- TigraanClick here for my talk page ("private" contact) 13:31, 11 July 2022 (UTC)
July 12
Diffraction spikes in the James Webb Space Telescope images
Either in the JWST’s first "promo" image (File:Webb's_First_Deep_Field.jpg) or in File:JWST Telescope alignment evaluation image labeled.jpg, one can see a strong hexagonal diffraction spike pattern around the brightest star.
I would assume that this is not very good for any serious image analysis (even if it looks pretty for the photo-op) and that this was not exactly a surprise to the telescope designers. Are there any countermeasures in place for when the scientific work begins, and if yes which? TigraanClick here for my talk page ("private" contact) 09:14, 12 July 2022 (UTC)
- This is clearly an important step in the image analysis, and there are methods of various levels of complexity of how to deal with the spikes and more generally the point spread function (PSF). The spikes from the brightest stars may well be beyond repair and the easiest way to deal with them is to mask them out, discarding all parts of the image covered by spikes and the stars from which they originate. There are, however, nice galaxies that sit right on top (or under?) a spike and it would be a shame to just throw them away. A heuristic model of the spike in that area may help in that case. More important is the question of how to deal with the PSF in general. The PSF is the image that a point source (i.e. a star) creates on the image. However, not only stars but all objects in the field are affected by the PSF. Some galaxies show distinct diffraction spikes, which are typically less sharp than those from stars. These originate from bright central regions of the galaxies that are extended yet compact enough for diffraction spikes to be discernible. Even if the spikes cannot be made out as such, the image of a galaxy is affected by the PSF. Mathematically, this is a convolution of the actual intrinsic image with the PSF. As long as the PSF is predictable (or can be measured by looking at the stars in the field), this is fairly simple to account for. In forward modelling, you build a model of the galaxy's intrinsic shape, then convolve that with the PSF and compare it to the image. Mathematicians usually think of deconvolution, but this is often problematic due to the noise in the image and artefacts that may be introduced through the algorithm. --Wrongfilter (talk) 10:17, 12 July 2022 (UTC)
- Diffraction spikes happen in every telescope (except those with perfect cylindrical symmetry, like most refractors or Schmidt–Cassegrains). It's an unavoidable consequence of the wave-like nature of light. Fortunately, the amount of light in the diffraction spikes is very small compared to that in the core of the object around which you see the spikes. In the deep field image, there are about 50 objects with clearly visible diffraction spikes and I expect all of them have, at their centre, well saturated the CCD. Those are useless. One can attempt to subtract the diffraction spikes from the image, but the noise in the diffraction spikes will remain, which is bad news for the objects behind a diffraction spike of one of these bright objects (which must be foreground stars of bright quasars). Fortunately, there must still be (tens of) thousands of objects in this image not affected by these spikes. PiusImpavidus (talk) 10:44, 12 July 2022 (UTC)
- If the field is important enough, the telescope could be rotated and another image taken. Saturated pixels will make it so that you cannot use an inverse PSF to remove the spike completely. If there was 32 bits of sampling, no noise or saturation, then perhaps they could be taken out. Graeme Bartlett (talk) 11:12, 12 July 2022 (UTC)
- There's always noise, if only Poisson noise. Suppose that within the area of a distant galaxy you detect 100 photons from that galaxy. That's your signal. Then your signal-to-noise ratio is a useful 10. Now add a diffraction spike with another 300 photons in the same area. This contains of noise. You can subtract the diffraction spike, if you can model it, but the noise in the diffraction spike will still be there. Your signal-to-noise ratio goes down to a marginal 5. PiusImpavidus (talk) 23:03, 12 July 2022 (UTC)
- My point was that you will not be able to do it, due to the assumptions not being true. I write from personal experience in computationally removing image problems by using the inverse PSF. Without noise, great results are possible. But there is noise, so it is not so good. Graeme Bartlett (talk) 23:45, 14 July 2022 (UTC)
- There's always noise, if only Poisson noise. Suppose that within the area of a distant galaxy you detect 100 photons from that galaxy. That's your signal. Then your signal-to-noise ratio is a useful 10. Now add a diffraction spike with another 300 photons in the same area. This contains of noise. You can subtract the diffraction spike, if you can model it, but the noise in the diffraction spike will still be there. Your signal-to-noise ratio goes down to a marginal 5. PiusImpavidus (talk) 23:03, 12 July 2022 (UTC)
Where the building blocks/nutrients come from in plants (and all living things)
Hello, I was just curious, I had heard most of the mass of trees comes from the air. In that case, what is the branch of science I would look up to know exactly how trees, plants, fruit, etc. get their building blocks and gain their specific nutrients, etc. Say the vitamin c from an orange or the protein in beans, or lycopene in tomatoes. Thanks kindly. Stocktrain (talk) 21:04, 12 July 2022 (UTC)
- You can read Plant physiology, Phytochemistry, Plant nutrition. Graeme Bartlett (talk) 22:00, 12 July 2022 (UTC)
- Does anyone know the answer in a nutshell? Thanks! Stocktrain (talk) 18:00, 14 July 2022 (UTC)
- Wikipedia might. Try reading the linked articles. --←Baseball Bugs What's up, Doc? carrots→ 21:22, 14 July 2022 (UTC)
- Does anyone know the answer in a nutshell? Thanks! Stocktrain (talk) 18:00, 14 July 2022 (UTC)
July 13
Stray cat skull differences
Are the skulls of stray and non-pedigreed cats of the same age as unique as human skulls? That said, can a specialist find the differences between two stray cat skulls of the same age? Thanks. 212.180.235.46 (talk) 17:17, 13 July 2022 (UTC)
- Are human skulls that unique? The shape of an individual's skull may change over the years, and the variation is considerably larger than that between closely matched pairs of skulls. Of course, given two randomly selected individuals, the chance that the shapes of their skulls cannot readily be distinguished is vanishingly small. I have no reason to suspect that this is not equally true for non-inbred cats. --Lambiam 20:59, 13 July 2022 (UTC)
July 14
Bio/Chemistry: salts and sugars.
When we run and sweat in the hot weather, we sweat a lot of salt. Therefore drinks like Gatorade have salt and electrolytes in it. If we drank a sugared-juice, can the body treat some of the sugar as if it were a salt? Or is that not possible.
And for the chemistry-side question, salts tend to be ionic, and sugars covalent. Can there be such a thing as a covalent salt, or an ionic sugar? I wonder if a difference between salts and sugars is the difference between ionic and covalent bonding. And obviously, we can have covalent polyatomic ions, that form ionic bonds, making it have both covalent and ionic bonds, I wonder if any of those are considered salts or sugars? Thanks. 67.165.185.178 (talk) 03:11, 14 July 2022 (UTC).
- From a physiological point of view, what is important are not the salts (minerals, being chemical compounds) as such, but the ions when the salts dissolve, known as electrolytes, such as sodium (Na+), potassium (K+), calcium (Ca2+) and magnesium (Mg2+). They each play a vital role, and cannot replace each other. So-called electrolyte imbalance can, in extreme cases, be fatal. Sugars do not provide the body with any of these vital electrolytes. Glucose is also important, but it cannot in any way be a substitute for any electrolyte. --Lambiam 07:46, 14 July 2022 (UTC)
- For the second part of your question, most sugars are not ionic but a small number do contain acidic groups, for example neuraminic acid which is a carboxylic acid. Such compounds can be ionised at physiological pH and can form, for example, sodium salts when reacted with sodium hydroxide. Mike Turnbull (talk) 13:45, 14 July 2022 (UTC)
- Just to clarify a bit more, salts are a basic synonym for ionic compounds, while sugar is a molecular compound, as noted above, the salts we care about are those that contain ions necessary for life (the list above is pretty good). Sugars are carbohydrates, which are not ionic and don't have the elements noted above. --Jayron32 17:35, 18 July 2022 (UTC)
July 15
The history of Lot with a scientific aspect
Is the history of Lot, can be real from the scientific science? It is written that he was so drunk that he couldn't know that he slept with his daughter, and from this even he got a son. Now my question is if it's possible to be such uncouncious and still have errection etc. ThePupil (talk) 01:00, 15 July 2022 (UTC)
- Right, not possible. 67.165.185.178 (talk) 05:03, 15 July 2022 (UTC).
- [Edit Conflict] Alcohol affects different people in different ways, significantly though not entirely due to inheritence of multiple genetic traits that (as so often in human physiology) may interact in complex ways with variable results. The traits involved have often been somewhat selected for or against in different populations according to those populations' deep historical exposure (or not) to alcohol. (In other words, if one's ancestral culture drank more alcohol, one will likely tolerate it better; if not; one may get incapably drunk more easily.)
- I can well believe it possible that someone could (a) be able to ejaculate whilst either (b) too drunk to recognise his "assailant", or sufficiently judgement-impaired to (c) go along with an inappropriate liaison and (d) suffer genuine memory loss afterwards: I myself have experienced (c) and (d) separately (the (c) occasion being adulterous, not incestuous, and in my case (a) did not apply!).
- All that said, most serious historians unbiased by faith would likely assess the biblical stories relating to that alleged era as myths constructed to explain various later-observed features, demographics and nomenclatures, and/or to teach various moral strictures, and in no way a genuine record of actually existing individuals or real historical events. See for a starting point Historicity of the Bible. {The poster formerly known as 87.81.230.195} 90.199.169.177 (talk) 05:28, 15 July 2022 (UTC)
- Surely this is one of the less implausible parts of Genesis 19, no? I would be more curious about the scientific explanation for verse 11, "they smote the men that were at the door of the house with blindness, both small and great"; or verse 24, "Then the Lord rained upon Sodom and upon Gomorrah brimstone and fire"; or verse 26, "his wife looked back from behind him, and she became a pillar of salt". Shells-shells (talk) 06:08, 15 July 2022 (UTC)
- Our article on erectile dysfunction doesn't list alcohol as a trigger, but even a quick search online finds plenty of sources to support the idea that drunk men often struggle to achieve or maintain an erection. But the question was - is it possible to be inebriated to the point of not recognizing close family while still being able to perform sexually - and that's not the same thing. I don't know if it passes muster as a WP:RS, but here is a first hand account of a man that was raped by a woman while inebriated and his story certainly sounds credible. As our article at rape of males notes, this type of crime is largely under-reported for a whole host of social and personal reasons. Consider also this: if the story was that Lot had gotten drunk and raped his daughters (instead of vice versa) it probably wouldn't elicit much commentary about being physically impossible: don't conflate the unlikelihood of one thing (daughters demanding sex of father) with another (drunk man having sex). Matt Deres (talk) 17:29, 15 July 2022 (UTC)
- It's probably a lot more likely than someone turning into a pillar of salt. --←Baseball Bugs What's up, Doc? carrots→ 19:20, 15 July 2022 (UTC)
- The story was of course set, and told for Iron-age culture listeners resident in or near, the Jordan Rift Valley, where there are extensive salt deposits and various wind-carved geological features in the desert or semi-desert terrain. Undoubtably there were (and are now – I've seen photos) one or more features suggesting through Pareidolia the figure of a woman. Similarly, this being an anciently inhabited region much fought over for thousands of years, there are any amount of ruined ancient city (or at least citadel) remains, as well as natural features resembling artificial structures.
- Consider the very extensive list of 'cities' that Joshua and his 'army' supposedly conquered and destroyed in a couple of years, although modern archeological evidence for those identified shows their various ends were spread over centuries (this being after the Late Bronze Age collapse). {The poster formerly known as 87.81.230.195} 90.199.169.177 (talk) 21:36, 15 July 2022 (UTC)
- Yes, I've seen similar photos. Basically a rock formation in search of a story. As to Joshua, maybe he had ultrasonic ram horns. --←Baseball Bugs What's up, Doc? carrots→ 01:05, 16 July 2022 (UTC)
- Didn't need them; archeology demonstrates that Jericho was reduced to ruins some three centuries before any reasonable setting date for the Exodus (etc.) story, and was essentially an uninhabited rubble pile when supposedly he "Fit the Battle." {The poster formerly known as 87.81.230.195} 90.199.169.177 (talk) 05:03, 16 July 2022 (UTC)
- That assumes they've correctly deduced where Jericho was. --←Baseball Bugs What's up, Doc? carrots→ 06:19, 16 July 2022 (UTC)
- Is (current population 20,000+). Its history goes back 11.000 years, its archeological record is extensive, and there was never a shred of doubt as to its location, even during the periods it was in ruins. Exodus was of course compiled/written long after it was rebuilt. {The poster formerly known as 87.81.230.195} 90.199.169.177 (talk) 22:25, 16 July 2022 (UTC)
- That assumes they've correctly deduced where Jericho was. --←Baseball Bugs What's up, Doc? carrots→ 06:19, 16 July 2022 (UTC)
- Didn't need them; archeology demonstrates that Jericho was reduced to ruins some three centuries before any reasonable setting date for the Exodus (etc.) story, and was essentially an uninhabited rubble pile when supposedly he "Fit the Battle." {The poster formerly known as 87.81.230.195} 90.199.169.177 (talk) 05:03, 16 July 2022 (UTC)
- Yes, I've seen similar photos. Basically a rock formation in search of a story. As to Joshua, maybe he had ultrasonic ram horns. --←Baseball Bugs What's up, Doc? carrots→ 01:05, 16 July 2022 (UTC)
- It's probably a lot more likely than someone turning into a pillar of salt. --←Baseball Bugs What's up, Doc? carrots→ 19:20, 15 July 2022 (UTC)
July 16
Radiation from handling nuclear weapons
I had a discussion with some friends a while ago about Soviet-era attack submarines with nuclear torpedoes, and if it was likely that the crew slept near the torpedoes. Some argued that it was impossible due to the long-term effects of radiation, some that there was probably some radiation but not more than what was acceptable to the Soviet Navy.
General question: what are the dangers of handling nuclear weapons to the ammunition specialists as of today? And more specific: what is known about Soviet-era nuclear weapons and the dangers from handling them? Sjö (talk) 07:38, 16 July 2022 (UTC)
- Most submarines of that era were nuclear-powered but didn't have nuclear torpedoes. They had nuclear missiles. The article Soviet submarine K-19 gives a pretty good account of some of the hazards the crew experienced. The main article on submarines has other details and links. Mike Turnbull (talk) 11:12, 16 July 2022 (UTC)
- Nuclear torpedoes - that is, torpedoes with nuclear warheads - definitely existed, and were deployed by both sides during the Cold War.
- The Soviet submarine B-59 came perilously close to firing its nuclear-tipped T-5 torpedo during the Cuban Missile Crisis. (T-5s had been deployed aboard Soviet submarines starting from 1958, and it is known that there was a flotilla of four T-5-armed subs in the waters around Cuba.) The USSR later developed the ASB-30 warhead, which could be swapped for the conventional high-explosive warhead on 533 mm torpedoes by the sub's crew while at sea. Eventually, it was not unusual for Soviet attack subs to carry up to four nuclear torpedoes. For example, the K-8 was carrying four nuclear torpedoes when it sank in 1970.
- While I'm having trouble finding good sources that specifically discuss radiation exposure from proximity to (unfired) nuclear weapons, I'll note that the risk was probably relatively low. The plutonium or uranium cores of fission weapons principally emit alpha particles, which have little penetrating power; they are handily stopped by a coat of paint, to say nothing of the metal casing of a torpedo. Both are most hazardous when ingested or (especially) inhaled—which really shouldn't happen with an intact warhead. The low-level gamma radiation that might escape the weapon's casing and irradiate nearby crew members would be more in the you might get cancer thirty years from now range, and much less the you're going to be puking your guts out by the end of the voyage levels. As you suggest, there were far bigger risks to the health of Soviet nuclear sailors. TenOfAllTrades(talk) 22:23, 16 July 2022 (UTC)
- From my past experience (including at an AWE), assembled nuclear munitions are safe to handle (in the correct manner) and be around, it's only when they are being assembled, or disassembled, that they're hazardous. Dropping pieces of Pu on the floor is to be avoided, as a colleage of mine discovered. [He suffered no long-term effects, but spending many unplanned hours in heavy-duty PPE while decontamination is performed around one is quite debilitating.] {The poster formerly known as 87.81.230.195} 90.199.169.177 (talk) 22:43, 16 July 2022 (UTC)
- The US Navy was worried enough to have a special low-radiation grade of plutonium: supergrade. Fgf10 (talk) 07:11, 17 July 2022 (UTC)
- Being on a submarine, protected from the sun, it is possible that the sailors are experiencing less radiation. This is not to say that all radiation is equal. But, solar radiation is dangerous. Removing that from daily life is a benefit that may counter the extremely tiny risk of an errant subatomic particle flying by. It is also possible that the condensed population of humans is a radiation hazzard because humans emit radiation as well. When I worked at Los Alamos, I held a nuclear battery for long-distance satellites. It is highly radioactive on the inside. On the outside, it emits less radiation than the person holding it. Is anyone going to bring up those deadly bananas? 12.116.29.106 (talk) 12:38, 19 July 2022 (UTC)
Looking for subject experts for the List of Domesticated Animals
I've been trying to delete dubious entries from the List of domesticated animals (in the second table, which is "tame and partially domesticated animals"). Some I can do pretty easily (eg "Yeah, the Wikipedia page makes no mention of this being kept in captivity, away it goes"--our standard, to avoid edit wars, is that to go on the first table the Wikipedia page for the animal needs to have some version of the word "domesticated", and/or the domesticated version needs to be a different species; for the second table, the Wikipedia page just needs to make some concrete mention of both its use by humans and at least some indication that they are captive bred, with elephants being the special exception because of our *long* relationship with them).
But some of them are about as clear as mud, in terms of figuring out if the animal is ever captive bred, and/or is kept in captivity extensively enough to count (zoos and wildlife reintroduction programs don't count, nor does, eg, a single rich eccentric having one as a pet). And some of the cases where there were multiple species (to keep the list from getting overlong, we group closely related species with other listed characteristics in common) and I deleted some of them, I'm not sure if the picture being used is of one of the species that is still on the list.
In particular, I could use an expert on snakes (for the rat snake and king snake entries), fish (for the carp and betta entries), and birds (for the cockatoo entries). But, honestly, any animal experts willing to take a glance at the list and go "Yeah, no, that's not captive bred/widely used by humans at all" would be appreciated (though, again, this page has had a *lot* of edit wars, please propose entries for deletion on the talk page, and I or someone else will actually delete them if no one objects after ~ 2 weeks)
Thank you. Tamtrible (talk) 23:53, 16 July 2022 (UTC)
- Why not use the same verifiability requirement as elsewhere on Wikipedia, namely that reliable sources classify the species or variety as (being) domesticated? --Lambiam 06:45, 17 July 2022 (UTC)
- The Zebra finch is a model organism and a popular pet, as its article says. It sounds like you consider "pet" to qualify as domesticated, although given people's propensity to try to make everything into a pet, that seems a pretty low bar. But anyway, they're certainly captive-bred all over the world, for science, so you should probably reinstate that one. I also found musk ox domestication. And Cassowary#Relationship with humans says they were partly domesticated once. Card Zero (talk) 09:20, 17 July 2022 (UTC)
- An important distinction I have heard is that individual animals are tamed, species are domesticated. Taming involves taking an individual animal and raising it so it is acclimated to humans. Domestication is a long, multi-generational process of breeding a species of animals for use by humans. Just about any animal can be "tamed" or even bred in captivity, but only a relatively small number of such animals have been domesticated. This video by CGP Grey provides a decent overview of the distinction. --Jayron32 11:30, 18 July 2022 (UTC)
- I agree with Jayron and Lambiam's comments. Emmer wheat, for example, was the archetype of modern domesticated varieties. I don't suppose anyone keeps wheat as a pet! The crucial aspect is that domesticated species, whether plants or animals, have developed phenotypes that make them more useful to humans. The process continues: for example in the way we breed racehorses and dogs by artificial selection. Mike Turnbull (talk) 11:49, 18 July 2022 (UTC)
- Also, the domestication of species takes centuries, if not millennia. Most (if not all) of the species we think of as "domesticated" occurred during the many centuries of the Neolithic Revolution. I'm not sure we have any historical examples (as in, since history started, i.e. not ancient pre-history) in the same way that, say, maize has been domesticated from teosinte or that cattle were domesticated from aurochs. There are some animals, like Norway rats and the house mouse, that might qualify as recently domesticated, though really these animals are accidentally domesticated as they basically co-evolved with humans over millennia to live alongside us; we just caught a few and bred them for specific purposes (lab rats and pet rats), but that's not the same as taking a wild species and domesticating them. I'd dare say that there aren't any modern domesticated animals that we can document the domestication of, with the possible exception of the experiments done in the 20th century on the Domesticated silver fox, but there are a LOT of questions as to the nature of domestication there... Although perhaps under some definitions, given the short life cycle, laboratory strains of Drosophila melanogaster may be "domesticated" for our purposes here. --Jayron32 17:06, 18 July 2022 (UTC)
- I agree with Jayron and Lambiam's comments. Emmer wheat, for example, was the archetype of modern domesticated varieties. I don't suppose anyone keeps wheat as a pet! The crucial aspect is that domesticated species, whether plants or animals, have developed phenotypes that make them more useful to humans. The process continues: for example in the way we breed racehorses and dogs by artificial selection. Mike Turnbull (talk) 11:49, 18 July 2022 (UTC)
- "Domesticated" is also a legal term. Many locations have laws banning certain pets. They rarely ban domesticated pets. I witnessed this sort of legal battle over a hedgehog. The owner claimed the hedgehog was domesticated, so it was legal to keep as a pet. Animal control argued that it was not domesticated, so it fell under exotic pets and was not legal. It came down to a judge to decide. The reason I remember this case is because I completely disagree with the judge's logic. Because the hedgehog is capable of surviving without a human owner, it is not domesticated. No need to complain that the judge's ruling is idiotic. I know. But, I feel this brings a whole new viewpoint into the discussion of domesticated vs non-domesticated animals. 12.116.29.106 (talk) 12:30, 19 July 2022 (UTC)
July 17
Lab worker with a valved respirator
NY Times article today on bat coronavirus research includes this photo of a lab worker testing human samples. [3] Is that a 3M Aura or similar? Imagine Reason (talk) 11:55, 17 July 2022 (UTC)
- If you zoom in it clearly says Aura and has the 3M logo, so one would imagine so. The numbers are harder to make out but appear to be 9332+. Nil Einne (talk) 14:51, 17 July 2022 (UTC)