Wikipedia:Reference desk/Archives/Science/2020 March 19

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March 19

Born blind

Do we have an article on the concept of being blind from birth? I looked for "born blind" and found Healing the man blind from birth, a miracle of Christ, and I looked for "congenital blindness" and found Congenital Blindness Gene Therapy, but I didn't find anything on the general concept of blindness from birth, which I assume would be the result of random imperfect development, or genetics, or something gone wrong, e.g. thalidomide. I'm envisioning there being room for such an article, looking at things like a child learning basic facts of existence without vision, and the way the eyes develop later in life if they were never formed properly. Nyttend backup (talk) 00:11, 19 March 2020 (UTC)

I don't see such an article and you're right it would be good to have one. The article childhood blindness doesn't say much about it, but "congenital blindness" has web hits. I remember reading that people who lose their sight continue to have visual imagery in their dreams, but people blind from birth don't. That would be an interesting thing to research. 2601:648:8202:96B0:386A:A40C:EBB1:ACC0 (talk) 00:43, 19 March 2020 (UTC)

How could you know if a person blind from birth had visual imagery in their dreams? How could they describe it to you? --Khajidha (talk) 02:00, 19 March 2020 (UTC)

One way is by studying REM sleep. I googled "dreams of people blind from birth" and various interesting items came up. Consensus of conjecture seems to be that being born blind results in auditory dreams rather than visual. However, this article[1] indicates that Rapid Eye Movement occurs even in those born blind. So while they might not be able to describe what they're "seeing", they still exhibit sighted activity. ←Baseball Bugs ^{What's up, Doc?} carrots→ 04:01, 19 March 2020 (UTC)

It's not clear that REM has anything to do with vision. There was an early belief (William Dement, an early REM researcher, wrote about this in his excellent book The Promise of Sleep) that REM followed the person's field of vision in whatever they were dreaming about, but that's now considered unclear. Rapid_eye_movement_sleep#Eye_movements discusses this a little. 2601:648:8202:96B0:386A:A40C:EBB1:ACC0 (talk) 08:08, 19 March 2020 (UTC)

And can people that were born color-blind, dream in color in their sleep? 67.175.224.138 (talk) 11:37, 21 March 2020 (UTC).

Besides genetic causes of blindness at birth, see also retinopathy of prematurity, which is less common than it was in the 1940s and 1950s (when it was common in premature infants as a side effect of high levels of oxygen in the incubator). Robert McClenon (talk) 04:23, 22 March 2020 (UTC)

The account of Healing the man blind from birth is the Gospel reading for today, Sunday, 22 March 2020, in Roman Catholic churches. Robert McClenon (talk) 04:23, 22 March 2020 (UTC)

Similarity of coronavirus symptoms to those of other illnesses

To what extent do symptoms of coronavirus infection resemble those of other illnesses such as the flu? How difficult are they to tell apart? Freeknowledgecreator (talk) 00:44, 19 March 2020 (UTC)

There is enough similarity that they have to do medical tests when they think someone might be infected with CV, and one of the big screwups of this situation is not enough testing materials. The US in particular dropped the ball badly. 2601:648:8202:96B0:386A:A40C:EBB1:ACC0 (talk) 02:30, 19 March 2020 (UTC)

Martian core

Composition of Mars says Mars has a molten iron core but no convection. Any idea why it wouldn't have convection if the core is molten? Isn't it cooling so it should have a temperature gradient? RJFJR (talk) 00:58, 19 March 2020 (UTC)

I've never looked into this with planets, but I am familiar with stars. I assume they're somewhat similar. Heat can be moved out by convection, by radiation (in stars) or by conduction (in planets). As heat moves out by radiation/conduction and the core cools, the temperature gradient drops. If the temperature gradient is less steep than adiabatic, the medium is stable and no convection will happen, although cooling will continue by radiation or conduction. Also see lapse rate, which is about gasses, but the same applies to liquids. The adiabatic lapse rate for liquids is much closer to zero than that for gasses. PiusImpavidus (talk) 10:54, 19 March 2020 (UTC)

This paper by Stevenson in 2001 suggests that there was convection in Mars' core at an earlier stage in its evolution - see Figure 3 in that paper. Mikenorton (talk) 16:56, 19 March 2020 (UTC)

Here's the cool (*rimshot*) article for this general topic: Earth's internal heat budget. (Focuses on Earth, but there's some discussion of other planets.) --47.146.63.87 (talk) 18:46, 19 March 2020 (UTC)

The article says "However, there does not appear to be convection in the mantle". Mars has a lower gravity, and if the temperature of the mantle is low enough, there will be no convection, as "For temperature changes of 100 degrees K, the viscosity changes by an order of magnitude at constant stress" 2003:F5:6F10:8A00:C9B9:26C3:C4CF:B3F0 (talk) 08:33, 23 March 2020 (UTC) Marco PB

• Maybe everyone who commented know and think it is obvious, but convection occurs only when the temperature gradient is above a certain threshold. See Heat_transfer#Convection_vs._conduction (a much better explanation than what is found in natural convection), or look for "critical Rayleigh number" in the literature. (Maybe there is some MHD magic that change the actual motion compared to standard convection, but the existence of a Rayleigh threshold should hold.) Tigraan^{Click here to contact me} 09:38, 23 March 2020 (UTC)

Coronavirus drugs

I'm hearing stuff about various drugs including an old malaria remedy looking promising against SARS-Cov-2. That's great, but they must have tried them against SARS-Cov-1, right? Are the two viruses different enough to make the new one (despite being much nastier in various ways) more easily treatable? Is it excessive media optimism? Or what? 2601:648:8202:96B0:386A:A40C:EBB1:ACC0 (talk) 08:03, 19 March 2020 (UTC)

A lot depends on exactly where you are "hearing stuff". There is a lot of nonsense circulating on social media; you should only get the facts from reputable sources.--Shantavira|^{feed me} 10:18, 19 March 2020 (UTC)

A number of existing anti-viral drugs are in clinical trials right now to see if they increase survival and/or accelerate recovery from Covid19. See Coronavirus_disease_2019#Antivirals. Someguy1221 (talk) 11:46, 19 March 2020 (UTC)

Here's a good resource: Understanding Unapproved Use of Approved Drugs "Off Label", from the FDA.

At least in the United States, you aren't allowed to sell or market a drug/medicine/pharmaceutical/medical-equipment unless you've passed the bar - both scientific and legal - to prove beyond doubt that your product does what it says it does.

This is a major reason why an already-existing drug, vaccine, or even a test, can't be sold as a "cure" - nor even as a diagnostic test - for a brand new disease. Broadly interpreted, the rules say that you have to prove that it works on this specific disease - not simply that it's a generally good medicine that can cure you from "the bad stuff."

It takes time and effort - formalized as a clinical trial - to show that a drug cures treats this illness. The same time and effort are needed just to show that a test actually works - for this specific illness.

But there are a lot of gray areas that emerge - especially in cases where a specifically licensed medical professional makes the judgement-call on a case-by-case basis. The key thing, though, is that these case-by-case judgement calls can not be commercially marketed to the wider public audience. Once the scientific and legal process is completed, only then the product or service can be sold to the public. These are long-standing, well-established rules and they exist for the purposes of promoting public safety. The commercial marketplace happens to have a very bad track-record of selling junk science, snake-oil medicine, and general quackery; and there is a lot of prior precedent of the very same shenanigans that get perpetuated by "respectable-looking companies."

Per the usual circumstances, during this very interesting administration, it seems very likely that our executive-branch may use "emergency decree" to bypass long-standing safety regulations.

So, it's a great thing to know that the "off-label" research-grade COVID-19 test - built on top of the industry-standard Roche cobas 6800/8800 laboratory platform - was emergency-approved by the FDA for diagnostic testing for the COVID-19 disease. This is, of course, a product and service that is marketed by a corporation with a long track record for the literal, actual crime of conspiracy to defraud the United States Government, 18 U.S.C. § 371, as well as multiple convictions for price-fixing, illegal contracting, antitrust violations, and all sorts of other no-good-ery...: "It is clear that there was an elaborate conspiracy that was kept entirely secret by a small group of employees..."

Well, that was just a minor half-billion-dollar criminal price-fixing conspiracy on simple nutritional supplements... At least we can trust these folks to correctly design and market safety-critical medical equipment - we have the best people in the world conducting mature, responsible government oversight!

Nimur (talk) 16:28, 19 March 2020 (UTC)

Doctors have always been allowed to prescribe drugs approved for one purpose for another unapproved purpose. The restriction is on the pharmaceutical firms, which cannot promote them - or even suggest that they might be effective - for off-label purposes. - Nunh-huh 12:48, 20 March 2020 (UTC)

University of Minnesota is testing "malaria treatment hydroxychloroquine can prevent or reduce the severity of COVID-19. Two other trials are studying the blood pressure drug losartan".[2] This comes after Italy, South Korea and China already started trials. Rmhermen (talk) 18:04, 19 March 2020 (UTC)

We have known for years apparently: "Chloroquine is a potent inhibitor of SARS coronavirus infection and spread", Virol J. 2005; 2: 69. Martin J Vincent, Eric Bergeron, Suzanne Benjannet, Bobbie R Erickson, Pierre E Rollin, Thomas G Ksiazek, Nabil G Seidah, and Stuart T Nichol

Meanwhile, other more recent research published by CDC concludes: "...chloroquine is not a suitable prophylactic or therapeutic option..." (for a different virus, Chikungunya Virus). In that research paper, treatment with chloroquine "paradoxically" made the illness worse: in the human study cohort, "no positive effect could be detected..." and in the non-human primates, this pharmaceutical intervention actually increased the rate of viral replication.

What will happen if we rush into a widespread deployment of that untested medicine? Will it enhance human health, or will it enhance the virus? The truth is, we simply do not know; and we are trusting our policy-makers to be scientifically informed enough to make a reasonable risk-reward judgement call.

Scientific research to propose and study new treatment is great, but digging up a few published papers is categorically not the same as vetting through rigorous, methodical clinical trials. We can't predict whether the outcomes are actually good or bad until we conduct rigorous controlled experiments, subject to outside regulation to make sure that the people doing the study aren't mistaken, or even intentionally lying about the results - because that part is actually a really really really huge problem.

That is why clinical trials are the golden standard before widespread deployment of a treatment or other disease intervention.

Nimur (talk) 22:03, 19 March 2020 (UTC)

This is something people often miss, thank you for making the point, Nimur. You often hear things like, "it couldn't hurt to try." But if we accept that a drug may have the power to alter the body's ability to fight off a virus, there is usually no particular reason to suspect this alteration must be in the positive direction. Someguy1221 (talk) 23:42, 19 March 2020 (UTC)

• There has been very recently a clinical trial in France purporting to show that said drug works. There are however giant methodology flaws (control group was self-selected by those who refused the experimental treatment, 20% dropout rate in the test group, final Ntest/Ncontrol=20/16 which is not enough, part of the test group took another medication, etc.). Moreover, the guy running the show said on TV that smaller sample sizes are better because you see more effect. I guess that is technically true that smaller samples are better for having nice results, not for doing proper science. Imagine the natural remission rate is 50%. If Ntest=Ncontrol=1 and my treatment does nothing, there is a 25% chance that only the test group patient gets better, and I observe my treatment makes remission rate go from 0% to 100%. On the other hand, if Ntest=Ncontrol=1000000, if the remission rate of the test group was 51%, that would already be significant evidence that the treatment helps. The best link I can give is the fr-wp page of the author because (as usual with successful cranks) the guy is clearly adept at navigating the media so coverage was overwhelmingly positive and any critical content comes from social media of actual researchers.

As Nimur said, properly testing medicine is expensive, hard, and time-consuming. As the public, and by way of consequence the politicians, want immediate results, cranks will flourish until the actual scientists have time to do the sciencing. Tigraan^{Click here to contact me} 10:25, 20 March 2020 (UTC)

Ingesting 50 ng of Polonium-210 will rid you of the virus. Count Iblis (talk) 10:50, 20 March 2020 (UTC)

No. But it will keep you from dying from the effects of the virus. DMacks (talk) 10:53, 20 March 2020 (UTC)