Wikipedia:Reference desk/Archives/Science/2020 July 6

= July 6 =

What's the relationship bewtween cyanosis and reality?
I have read the article cyanosis but still don't understand the way we see a bluish person while he doesn't have any kind of blue substant. The colour of unoxygenated blood isn't blue. (See here). It's written in the article: "The blood reaching the extremities is not oxygen-rich and when viewed through the skin a combination of factors can lead to the appearance of a blue color". What are these factors? --ThePupil (talk) 01:51, 6 July 2020 (UTC)
 * Skin absorbs red light more than blue. --Khajidha (talk) 02:16, 6 July 2020 (UTC)
 * Is that another way of saying that skin is blue? -- ToE 11:58, 6 July 2020 (UTC)
 * Did Hemoglobin (linked to from cyanosis) fail to answer your question? --Guy Macon (talk) 12:48, 6 July 2020 (UTC)
 * No. See https://www.livescience.com/32212-if-blood-is-red-why-are-veins-blue.html --Khajidha (talk) 14:13, 6 July 2020 (UTC)
 * Also, see the above discussion about color and perception. Color doesn't really exist in the world, it is created in your perceptions. What exists outside of you is simply electromagnetic waves. --Khajidha (talk) 14:42, 6 July 2020 (UTC)
 * Why do veins appear blue? A new look at an old question[ResearchGate], Lothar Lilge, et al., Applied Optics, March 1996. -- ToE 21:47, 6 July 2020 (UTC)
 * There's a relationship between veins appearance to the skin appearance in case of cyanosis? (cyanosis isn't limited to the veins but it seems on the skin. Also veins in healthy people looks bluish while cyanosis is a pathological sign) --ThePupil (talk) 00:01, 7 July 2020 (UTC)
 * As an aside it is interesting just how small a range of the Electromagnetic spectrum is visible to the human eye - to me anyway. MarnetteD&#124;Talk 00:06, 7 July 2020 (UTC)

Wearing masks and
Does wearing a mask for a while capture in the mask? After a while of wearing a mask, I start to feel like I'm not getting enough oxygen. Bubba73 You talkin' to me? 03:36, 6 July 2020 (UTC)


 * There's nothing to capture any appreciable amount of CO2. See here, for example. --174.89.49.204 (talk) 04:06, 6 July 2020 (UTC)


 * What's more likely happening is that moisture in your exhaled breath is condensing in the mask, reducing the amount of air a normal breath delivers to your lungs. This moisture can also create a lovely breeding ground for all sorts of nasties.HiLo48 (talk) 04:17, 6 July 2020 (UTC)
 * At most, that would be normal in terms of effort (feels harder to take in the breath). But the same size breath is still the same amount of air. The humidity might be higher as well. It feels to me more like breathing on a hot humid day because, well, I'm breathing through a warm humidifier. There's a TikTok or similar video circulating of someone using a pulse oximeter to demonstrate that maskless and a variety of mask types do not alter her 99% reading. DMacks (talk) 05:49, 6 July 2020 (UTC)
 * It's pretty obvious that any mask retains a small amount of warm air that is heavy in CO2 and moisture, but the volume of air under the mask is small compared to the volume of your lungs. You are already re-breathing CO2 and moisture from your windpipe and from the air sacks not emptying completely. None of this is at all dangerous. The only effect is to make wearing a mask is slightly annoying. (editorializing) You know what else is annoying? Having grandma or some fellow who recently experienced cardiac arrest die because you weren't willing to put up with a slight annoyance. --Guy Macon (talk) 12:26, 6 July 2020 (UTC)


 * 'The WHO says: "The prolonged use of medical masks when properly worn, does not cause CO2 intoxication nor oxygen deficiency. While wearing a medical mask, make sure it fits properly and that it is tight enough to allow you to breathe normally. Do not re-use a disposable mask and always change it as soon as it gets damp."' From: BBC - Coronavirus: 'Deadly masks' claims debunked. Alansplodge (talk) 15:57, 7 July 2020 (UTC)

Thanks. Bubba73 You talkin' to me? 02:26, 8 July 2020 (UTC)

Flu & Covid
How can someone get the flu if they have been following all of the covid guidelines? Facemask, hand washing etc. Is it the case that they could just as easily have contracted Covid in this situation but they were "lucky" enough to just get Influenza, or are these two viruses dissimilar and contracted through different methods? Thanks — Preceding unsigned comment added by 86.162.76.127 (talk) 10:07, 6 July 2020 (UTC)


 * The two are not exactly the same, so one may be more infectious or able to survive outside the body better, but in general they spread the same way, so the same methods - masks, handwashing, not touching the eyes or mouth, cleaning surfaces, social distancing, isolating yourself when you are sick -- will reduce both kinds of infections.

--Guy Macon (talk) 12:38, 6 July 2020 (UTC)
 * https://www.youtube.com/watch?v=D8hdjviABYo
 * https://www.youtube.com/watch?v=v0KAgR5QAJU
 * Also, the only thing that 100% prevents you from contracting any virus is to not encounter it. Precautions reduce risk, but do not absolutely prevent infection. The hypothetical person could have contracted the flu, covid, a cold, or any of a number of other respiratory viruses despite precautions. They just happened to encounter and contract the flu. --Khajidha (talk) 14:22, 6 July 2020 (UTC)
 * Pedantry: if a virus can't infect humans you of course can't get infected with it. You've got tons of bacteriophages in your gut and on your skin/other "outside" surfaces, but they're not a problem for you; in fact they're often beneficial by helping to keep bacterial populations in check. --47.146.63.87 (talk) 19:42, 6 July 2020 (UTC)
 * Unless it mutates to become infectious to humans. At which point things can get really ugly. See current events.--Khajidha (talk) 12:56, 7 July 2020 (UTC)
 * Yes, viruses can mutate to infect new hosts. These are usually similar species; zoonotic diseases that have "jumped" to humans have generally done so from other mammals or birds. A bacterial virus is very unlikely to "jump" to eukaryotes. --47.146.63.87 (talk) 16:14, 7 July 2020 (UTC)

Are there non-human mammals where the typical female does not have two X chromosomes?
I know birds and some other non-mammals use a system where the female has two unalike chromosomes (ZW vs ZZ). Are there non-human mammals where the typical female (barring intersex conditions, etc) has something other than XX chromosomes? I ask because XY sex-determination system says (emphasis added) "The XY sex-determination system is [...] found in humans, most other mammals, [...] In humans, most mammals, and some other species, two of the chromosomes, called the X chromosome and Y chromosome, code for sex." Male says: "Most male mammals, including male humans, have a Y chromosome". Female until recently said "most female mammals, including female humans, have two X chromosomes", but the lead (but not body) was changed to drop "most", and I'm trying to figure out if that change was correct or not. The fact that none of these articles cites a source for its statements on this matter is less than helpful. -sche (talk) 17:02, 6 July 2020 (UTC)
 * Some human females are XO. Or XXX. Or XY with non-functional SR-Y alleles. I assume the same conditions occur in other mammals. And monotremes get REALLY weird. --Khajidha (talk) 18:20, 6 July 2020 (UTC)
 * Echoing the previous reply. : Monotremes have all kinds of wild stuff going on, because they're believed to be the most basal living mammals. Therians are more like what we're "familiar" with because we are therians, although at a quick glance I can't find an explicit statement that all marsupials use the XY system. --47.146.63.87 (talk) 19:37, 6 July 2020 (UTC)
 * Thank you both! :) (I now notice that the body of the Female article indeed mentions platypuses; I didn't spot it / recognize it earlier because it doesn't actually say what they use instead, which is apparently a system of ten sex chromosomes.) -sche (talk) 08:06, 7 July 2020 (UTC)

worldwide lockdowns MAP
I can´t find worlwide map of countries who applied lockdowns and where not. it was avalaible a few weeks ago. ¿Where is it? — Preceding unsigned comment added by 190.163.188.62 (talk) 18:10, 6 July 2020 (UTC)


 * See Category:World maps about the COVID-19 pandemic. Probably one of those. If not, it's been deleted. Alansplodge (talk) 15:50, 7 July 2020 (UTC)

Is there any successful treatment and/or cure for presbyesophagus for people aged 110+?
If a person aged 110+ has presbyesophagus, is there any successful treatment and/or cure for this for this person? I am especially thinking of cases where presbyesophagus threatens this person's life by preventing them from getting adequate nutrition and nourishment. Futurist110 (talk) 20:23, 6 July 2020 (UTC)
 * If you want general info about the topic we have an article on Presbyphagia, but it really does look like you are looking for medical advice. Here is my medical advice: Accompany the person as the see an M.D. and ask her what can be done. --Guy Macon (talk) 22:15, 6 July 2020 (UTC)
 * The person in question was Walter Breuning, who died several years ago, age 114. ←Baseball Bugs What's up, Doc? carrots→ 00:59, 7 July 2020 (UTC)
 * I see no evidence that Walter Breuning had presbyesophagus, much less died of it. He died in a hospital, so I assume that they did what they could to keep him alive. --Guy Macon (talk) 04:13, 7 July 2020 (UTC)
 * See Futurist110's thread in the Humanities page. ←Baseball Bugs What's up, Doc? carrots→ 06:46, 7 July 2020 (UTC)

It would have been nice to have been alerted to the previous discussions. I'm just saying. --Guy Macon (talk) 14:43, 7 July 2020 (UTC)
 * Reference desk/Humanities
 * Reference desk/Humanities
 * Well, now you know. Anyway, after doing some research and discussions on this topic, one doesn't actually have to die from presbyesophagus, correct? Rather, one can be kept alive by being fed through a feeding tube, no? If so, this raises the question of why this was not done in Walter Breuning's case. Did Walter Breuning make a conscious decision to die as opposed to continue living but be fed through a feeding tube? Futurist110 (talk) 16:06, 7 July 2020 (UTC)
 * This is what can happen when you spread a discussion across 2 or more ref desk pages. As to your speculative questions, since his cause of death was not publicly stated, how likely is it that such details would be? ←Baseball Bugs What's up, Doc? carrots→ 21:01, 7 July 2020 (UTC)