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October 15[edit]

Hair color articles[edit]

Why is the black hair color article so much more sparse than the blonde and brown hair color articles although there are many more people in the world with black hair?

Also when looking at articles of melanin pigmentation why are individuals with light skin tones consistently depicted before individuals with dark skin tones when illustrating black hair?

Also why are so few people of dark skin tones and afro-textured hair represented in hair articles outside of afro-textured specific articles?

I'm trying to find scientific information on hair and hair color and information on one group of people seems to be purposefully excluded or ignored. — Preceding unsigned comment added by (talk) 06:06, 15 October 2020 (UTC)

Please read Wikipedia:Systemic bias. You are very welcome to improve Wikipedia.--Shantavira|feed me 07:36, 15 October 2020 (UTC)
If not for us folks with rarer hair colors, there would be no "black hair" article, it would be merely "hair". —Tamfang (talk) 02:08, 20 October 2020 (UTC)

October 16[edit]

Is it possible to sequence degraded genomes by taking many samples?[edit]

I know that DNA degrades over time, but it degrades equally throughout the body? Would it be possible to take ten, a hundred, a thousand samples or more than one organism in a zoological sample, be it a Pleistocene animal or a well-preserved or poorly preserved hundred-year-old organism, and sequence its entire genome? How much would this cost? (talk) 12:40, 16 October 2020 (UTC)

Theoretically yes, but I am not sure it is of any practical significance as DNA degrades too fast. Ruslik_Zero 14:13, 16 October 2020 (UTC)
Yeah, sometimes it's gone completely after only 300,000 years. (talk) 04:51, 18 October 2020 (UTC)
Possibly the currently leading scientist in this area of study is Svante Pääbo: you might try following up links in that article to see if they lead to any more specific answers. My own extremely lay understanding (gleaned from my amateur interest in paleoanthropology) would lead me to reply "something kinda sorta like this is already being done, but it's way more complicated than that." {The poster formerly known as} (talk) 21:10, 16 October 2020 (UTC)
Yes, all sequencing, not only of old genomes, is made by repeating the sequencing several times with different cells or individuals, this is necessary in order to recognize sequencing errors and random variabilty like Single Nucleotide Polymorphism. The result of any single sequencíng of a genome fragment is called a read and the number of complete sequences is called coverage, see Coverage_(genetics)
Today sequencing one genome costs round $1,400 2003:F5:6F11:9700:E984:90F6:23B5:2DB4 (talk) 16:03, 17 October 2020 (UTC) Marco PB
Returning to your original post re DNA degredation: this is hastened by higher and varying temperatures, and exposure to moisture, which is why it's harder to get good samples of of old DNA from more tropical areas, as opposed to northerly dry caves. Another major factor is contamination by the DNA of microbes and other fauna that may be present in the environment, not to mention that of the archeologists and others who handle the specimens! Some of the oldest recoveries of well-preserved DNA have recently been made by drilling into the interior of intact teeth (which themselves preserve better and longer than the rest of the body). {The poster formerly known as} (talk) 12:13, 18 October 2020 (UTC)

thank you, you were of great help. — Preceding unsigned comment added by (talk) 22:55, 18 October 2020 (UTC)

Impulse of black powder rocket motors[edit]

Our article Black powder rocket motor states: "The E class 24 mm motors have a maximum thrust between 19.4 and 19.5 N, a total impulse between 28.45 and 28.6 N·s, and a burn time between 3 and 3.1 seconds." However, 19.4 * 3 = 58.2, which would suggest that the motor should have a much higher impulse. My guess is that the impulse is calculated by integrating the force with respect to time, and since the actual force at any given moment is considerably less than the maximum for much of the flight, the reported impulse is lower. Is this correct? --PuzzledvegetableIs it teatime already? 16:17, 16 October 2020 (UTC)

Peak power (or peak thrust, in this example) is not identical and is quite a lot higher than the average power (or average thrust, in this example).
If the engineering data sheet was very extraordinarily detailed, it could plot (or otherwise specify) the thrust as a function of time; and you could more correctly estimate a total impulse by integrating the thrust over time.
From NASA's Glenn Research Center educational outreach for K-12 students ("the Beginner's Guide to Propulsion"), here is the general thrust equation, using notation that I'd normally expect to see presented to college-level physics or math students. Perhaps the next generation is more mathematically prepared than we have all feared! This presentation also introduces some of the specialized simplifications to the basic general equations of kinematics that are often nominally used to specify rocket impulse.
Nimur (talk) 16:45, 16 October 2020 (UTC)

October 17[edit]

Male and female body strength[edit]

Is it true that only about 1 out of every 1,000 women are as strong as the average man is? Futurist110 (talk) 08:21, 17 October 2020 (UTC)

Before we even try to discuss this, do you have a source for that claim? It clearly requires some tighter definition. HiLo48 (talk) 09:30, 17 October 2020 (UTC)
The user "A New Radical Centrism" on Twitter in one of his Tweets. Futurist110 (talk) 19:48, 17 October 2020 (UTC)
Per HiLo, please provide the source for your claim. Otherwise, your claim can be dismissed out-of-hand with no need to address it. --Jayron32 09:59, 17 October 2020 (UTC)
Isn't the reference desk a place to ask for supporting evidence? Alansplodge (talk) 13:09, 17 October 2020 (UTC)
That's clearly nonsense. Think about it. I reckon I am of average strength and I know plenty of women stronger than me. Did you know Wikipedia has an article on Sex_differences_in_human_physiology.--Shantavira|feed me 11:45, 17 October 2020 (UTC)
"A study in the Journal of Applied Physiology found that men had an average of 26 lbs. (12 kilograms) more skeletal muscle mass than women. Women also exhibited about 40 percent less upper-body strength and 33 percent less lower-body strength, on average, the study found". From Livescience - Women in Combat: Physical Differences May Mean Uphill Battle referencing Journal of Applied Physiology - Skeletal muscle mass and distribution in 468 men and women aged 18–88 yr. The Livescience article says that in armies where women are able to fulfill frontline infantry roles with a training regime comparable to the US Marines, they represent around 10% of the total strength, which might be a truer figure than the 0.1% quoted by Futurist above. Alansplodge (talk) 13:09, 17 October 2020 (UTC)
This study [1] says "Results indicate that untrained men have greater upper and lower body strength than trained women athletes in terms of both absolute and relative strength." There's a graph in another study [2]. In punch power the men won every time [3]. (talk) 14:07, 17 October 2020 (UTC)
Testosterone levels are lower in women. If this is corrected for the difference vanishes. Count Iblis (talk) 19:50, 17 October 2020 (UTC)
Going off at a tangent, Count Iblis, but that video is both informative and moving. Should we add the link to the relevant Article? {The poster formerly known as} (talk) 12:16, 18 October 2020 (UTC)
Looking at some data on grip strength it seem that the difference between the sexes is large. Taking a couple of (middle) age ranges individually, the average male grip exceeds that of the female by around 3.5 standard deviations of the female grip. If female grip strength is normally distributed, very few females indeed would have a grip as strong as an average male of the same age. catslash (talk) 15:37, 18 October 2020 (UTC)
A couple of other observations on this data: (1) for the youngest children, the females were the stronger, (2) the standard deviations for the males are relatively large - perhaps a small proportion of particularly strong males are boosting the male average. catslash (talk) 15:46, 18 October 2020 (UTC)
Interesting information! Futurist110 (talk) 02:44, 19 October 2020 (UTC)

October 19[edit]

If two men have anal sex and one man cums inside of the other man's anus, can this man's sperm get inside of the other man's prostate?[edit]

If two men have anal sex and one man cums inside of the other man's anus, can this man's sperm get inside of the other man's prostate--for instance, by forming microchannels/passages/a fistula that would allow it (as in, this man's sperm) to penetrate and enter the other man's prostate? Futurist110 (talk) 02:45, 19 October 2020 (UTC)

  • Futurist110, do the little sperms have little drills or other devices with which to drill microchannels? Drmies (talk) 02:48, 19 October 2020 (UTC)
    • Worst construction company ever? Double sharp (talk) 09:34, 20 October 2020 (UTC)
Well, I don't think so, but at the same time, I do know that if the top part of the vas deferens is sealed shut (using electrocautery or whatever) during a vasectomy, then sperm can nevertheless manage to enter the top part of the vas deferens later on in spite of the top part of the vas deferens being shut if the bottom part if the vas deferens will regenerate and reattach itself to the top part of the vas deferens. You would think that sealing the top part of the vas deferens shut would, you know, prevent sperm from entering it even if the bottom part of the vas deferens did regenerate and recanalize, but apparently that's not actually the case in real life, since otherwise there would not have been any vasectomy failures at all--ever! Not even a single one! Futurist110 (talk) 04:18, 19 October 2020 (UTC)
"There's a vas deferens between men and women", as a doctor friend of mine is fond of saying. -- Jack of Oz [pleasantries] 08:02, 19 October 2020 (UTC)
You should pick deferent friends.  --Lambiam 09:20, 19 October 2020 (UTC)
I defer to your wisdom. —Tamfang (talk) 02:11, 20 October 2020 (UTC)
I don't think this is going to work as a defence in a paternity suit.  --Lambiam 09:22, 19 October 2020 (UTC)
I never said that it will. I just find it weird that sealing the vas deferens shut does not, in fact, actually permanently seal it shut. Futurist110 (talk) 18:51, 19 October 2020 (UTC)
Who says it doesn't? ←Baseball Bugs What's up, Doc? carrots→ 12:05, 20 October 2020 (UTC)
Vasectomy failures. Futurist110 (talk) 19:44, 20 October 2020 (UTC)
If the urologist does it right, it shouldn't fail. ←Baseball Bugs What's up, Doc? carrots→ 23:49, 20 October 2020 (UTC)
If any cell can enter a man's prostrate from his anus, he has a condition (stabbed with a bayonet?) that urgently needs medical attention.  --Lambiam 09:26, 19 October 2020 (UTC)
And if it gets into his prostate, that's even worse. -- Jack of Oz [pleasantries] 21:36, 19 October 2020 (UTC)
How so? Futurist110 (talk) 00:25, 20 October 2020 (UTC)
Jack is pointing out that prostateprostrate. —Tamfang (talk) 02:12, 20 October 2020 (UTC)
Though he is presumably prostrate while all this is happening. (talk) 11:19, 20 October 2020 (UTC)
could be supine. --Jayron32 12:19, 20 October 2020 (UTC)
Perhaps if the sexual activity happens an astonishingly short period of time after a prostate biopsy? EdChem (talk) 13:26, 20 October 2020 (UTC)

Do influenza viruses cause the common cold?[edit]

The Common cold article says that a cold can be caused by influenza viruses. Other than the reference provided, I can't find any other source for that. I thought the flu is defined as the disease caused by the influenza virus. Is the article correct? And can a disease be both a cold and a flu? Cheesycow5 (talk) 23:00, 19 October 2020 (UTC)

I suspect a big problem here is the sloppiness surrounding proper definition of the common cold. In common speech in my part of the world the words cold and flu are used interchangeably by many, so declaring what virus is behind a particular case is not easy. HiLo48 (talk) 23:16, 19 October 2020 (UTC)
Are you telling me that the flu is not just the deluxe version of the cold?  ̄ω ̄ Double sharp (talk) 00:12, 20 October 2020 (UTC)
You're conflating two things: words people use to describe how they feel, and infectious agents that cause diseases. The words "cold" and "flu" refer in common speech to two different vague sets of symptoms. When a person self-diagnoses with one or the other, they frequently mean something like, in the case of a cold, an upper respiratory infection that usually results in things like stuffy or runny nose, sneezing, cough, and sore throat. A flu tends to mean something which causes a high fever, lethargy, body and head aches, etc. While flus can have stuffy noses, and colds can have fevers, in general people be more likely to describe colds as "a thing which is mostly a stuffed up head" and a flu as "a thing which is feverish and achy". That's also why people will use terms like stomach flu, which is feverish, achy, and shitty (in a literal term), but not caused by an influenza virus. Note that this has NOTHING to do with the actual infectious agent causing the disease, merely the words people use to describe themselves and how they are feeling. Cold-like symptoms (with a mild fever and more sever stuffy head) can be caused by influenza viruses. It doesn't mean people, who have not been diagnosed properly by a medical test, would use the term "flu" for those symptoms if they haven't been diagnosed with influenza. When you see the statistics in that page you linked that say that 10-15% of colds are caused by influenza viruses, what that means is that people who present symptoms they would describe as "having a cold" turn out to have been infected with an influenza virus. --Jayron32 12:15, 20 October 2020 (UTC)

October 20[edit]

What's the reason that people in the ancient time believed that removal of spleen will help them to run?[edit]

Is it known what's the reason that people in the ancient time (especially in the Roman or Greek empire If I'm not mistaken) believed that removal of the spleen will help them to run without limit or faster?--ThePupil (talk) 19:51, 20 October 2020 (UTC)

Did they believe that? Which "ancient people" believed this? --OuroborosCobra (talk) 21:13, 20 October 2020 (UTC)
see here.
Quoting from Side stitch: "A leading theory is that the pain may be caused by an increase in blood flow to the liver or spleen." Perhaps this has something to do with it.  --Lambiam 23:26, 20 October 2020 (UTC)

Thank you. I found more information here too. --ThePupil (talk) 07:05, 21 October 2020 (UTC)

From that source: "In 1922 this myth was tested in the laboratory at Johns Hopkins University, where Macht and Finesilver observed that asplenic mice were able to run faster than mice with an intact spleen". Alansplodge (talk) 08:43, 21 October 2020 (UTC)

October 21[edit]

Yearly influenza vaccine development time vs. other vaccines[edit]

How come it is possible to develop and deploy a different influenza vaccine yearly (or twice yearly, 1X per hemisphere), but the fastest effective vaccine took 5 year to develop and some COVID-19 vaccines could take at least 18 months (or longer)?

Doesn't the influenza vaccine need thorough testing? Couldn't it cause serious side-effects or even death? --Bumptump (talk) 12:48, 21 October 2020 (UTC)