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June 17

Using modern medical knowledge, what is Sarah chances of getting pregnant at the age of 90 if she had sex at her most fertile day?

“Shall a child be born to a man who is a hundred years old? Shall Sarah, who is ninety years old, bear a child?” (Genesis 17:17) Using modern medical knowledge, what is Sarah chances of getting pregnant at the age of 90 if she had sex at her most fertile day? Let's assume she never reached menopause. 49.177.234.140 (talk) 09:35, 17 June 2019 (UTC)

You're asking about a Bible myth. ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:11, 17 June 2019 (UTC)

At those ages, the only real chance would be in vitro fertilization using frozen sperm and eggs from their younger days, implanted in a surrogate mother, and raised by an adoptive family, since they are unlikely to be able to bring the child to adulthood. (The surrogate mother and adoptive mother might be the same person.) SinisterLefty (talk) 11:14, 17 June 2019 (UTC)

• Pretty good chances. Your "never reached menopause" assumption is the tricky one. Andy Dingley (talk) 11:44, 17 June 2019 (UTC)

Did you check menopause and Sarah#Historicity? Gem fr (talk) 15:12, 17 June 2019 (UTC)

You are using the modern definition of age as being 365.25 days long. That definition of a "year" didn't exist at the time of the Biblical stories. 68.115.219.130 (talk) 18:26, 17 June 2019 (UTC)

There was some speculation (see Methuselah#Mistranslation) that some Biblical ages were actually their ages in months, but I don't see how that could apply here, as that would mean Sarah was like 7-8 years old. SinisterLefty (talk) 19:20, 17 June 2019 (UTC)

Besides, the surprise of the pregnancy comes from her being old already. And she died at 127 ″years″. Now, for 2 cents I can add that, if those years were, say, ~6 month long, her pregnancy would had occurred at ~45y (which could be considered old), and she would have died at ~63 (a respectable age). Gem fr (talk) 19:40, 17 June 2019 (UTC)

But why would anyone measure ages in 6 month increments ? The use of months is common in hunter/gatherer societies, where the phases of the Moon are important, allowing for night hunting when the Moon is up and nearly full, and of course relating to women's periods. Annual cycles are more important to farmers, as they control the time to plant and harvest. SinisterLefty (talk) 19:51, 17 June 2019 (UTC)

well, this can happen if you mistranslate "season" into "year" in a context where a year is made of 2 seasons, which happens quite a lot, including for herders (of which Abraham was). (caveat: this is just, then again, my 2 cents). Gem fr (talk) 20:04, 17 June 2019 (UTC)

When I took ancient history (focusing on Egypt, Greece, and Rome), it was important to note that a "year" was not 365 days long. There were generally 10 months in a year. Sometimes a year had more. Sometimes it had less. A month was not a "moonth" as expected. It had been transformed into a tax cycle. Every month, people had to pay taxes. Every year, you had yearly taxes. If the government wanted more money, it was a new month. If they needed more money, it is a new month again. During war, years wizzed by faster and faster. During peace, years slowed down and took much longer to pass by. Then, with all this nonsense, the Romans wanted to normalize the calendar. That wasn't until after 400AD. So, it was hundreds of years after the stories from Genesis. If you take the variable concept of a year and add exaggeration of oral tradition, it is very easy to get people who are hundreds of years old. 68.115.219.130 (talk) 13:03, 18 June 2019 (UTC)

When you look better, it appears that romans were, at that time, just barbarians. Abraham came (so they say) from Ur, which had very solid foundations in mathematics, astronomy, etc. and used an elaborate calendar, just as good as the Julian. There is no way your explanation can hold Gem fr (talk) 19:14, 18 June 2019 (UTC)

My take is: not zero chance so it can happen, but so low chance you would make a story out of it, still remembered after millennia. Gem fr (talk) 20:13, 17 June 2019 (UTC)

Are glucocorticoids and catecholamines regulated by different systems of the body?

Are glucocorticoids and catecholamines regulated by different systems of the body? According to the book I read now "glucocorticoids secretion is regulated by hypothalamic - pituitary system" and some rows later "Catecholamines secretion is under the control of the central nervous system". Does it mean that the glucocorticoids are not regulated by the CNS? (I thought pituitary gland is a part of the CNS too. Isn't it? ) 93.126.116.89 (talk) 19:54, 17 June 2019 (UTC)

Yes and no. Glucocorticoids and catecholamines are both synthesized in and released into the bloodstream from the adrenal glands. However, glucocorticoid release is primarily regulated by the HPA system, as your book stated. Catecholamine release is controlled by the sympathetic nervous system. So, glucocorticoid release is controlled indirectly by the brain through endocrine signalling, while catecholamine release is controlled directly by action potentials transmitted through the sympathetic nerves. --47.146.63.87 (talk) 06:12, 18 June 2019 (UTC)

Our sun

What colour is it? 86.8.201.99 (talk) 22:22, 17 June 2019 (UTC)

The Sun is a yellow dwarf, but it is actually white. This is obvious when you see the Sun high overhead, through a layer of clouds (note: I make no representation as to how dangerous it might be to look at the Sun this way).

I think the reason most people think the Sun is yellow is that it looks yellow in the late afternoon (or early morning, I suppose, if you're that sort of person) when it is low enough in the sky to look at briefly without having a reflex to look away immediately. --Trovatore (talk) 22:33, 17 June 2019 (UTC)

It can also look red or orange when near the horizon, depending on atmospheric conditions. Looking at pictures of solar eclipses, the corona appears white. And using a primitive but effective cardboard box with a pinhole "projector", again the image looks white. ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:09, 18 June 2019 (UTC)

It can even sometimes appear green. SinisterLefty (talk) 02:09, 18 June 2019 (UTC)

If it's millions of degrees why isn't it blue even in photographs? If a googolplex Celsius blackbody is blue why is lightning violet? Sagittarian Milky Way (talk) 00:20, 18 June 2019 (UTC)≈

Our article says the Sun's surface temperature is 5778 K, or 9941 °F, so not close to "millions of degrees". The core reaches millions of degrees, to be sure, but those photons don't make it to the surface. --Trovatore (talk) 00:38, 18 June 2019 (UTC)

I know that. The corona is extremely hot. If it wasn't orders of magnitudes less dense than the photosphere it'd be astoundingly bright. Is the visible light part of the emission lines distributed such that it isn't strongly colored? Sagittarian Milky Way (talk) 02:17, 18 June 2019 (UTC)

According to corona, "[t]he corona is 10^-12 times as dense as the photosphere, and so produces about one-millionth as much visible light." So for purposes of everyday viewing it doesn't matter what color it is, because you can't see it next to the Sun anyway. It can be viewed during a total eclipse, and if what you mean to ask is for an explanation of the perceived color of that, I guess I don't know, but it was hardly clear that that was what you were asking. --Trovatore (talk) 02:43, 18 June 2019 (UTC)

The article on Lightning says its color is kind of blue-white, not violet. ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:01, 18 June 2019 (UTC)

The sky around the lightning might be violet, though, especially at dusk, so they might conflate the color of the two. SinisterLefty (talk) 02:04, 18 June 2019 (UTC)

Another factor to consider is our "mental white balance". That is, since we have a yellowish star, we tend to see that as white. If we had a bluish star, we likely would have evolved to see that as white. There's even a quick adjustment to the color. Try on different colored sunglasses, and the scene will seem to be different colors, but if you leave one pair on for a while, that will set the new white balance in your mind. SinisterLefty (talk) 02:22, 18 June 2019 (UTC)

We don't have a "yellowish star". It's white. As you note, that's essentially where our concept of "white" comes from, but nevertheless that's what it is. It just isn't yellow, period. --Trovatore (talk) 02:28, 18 June 2019 (UTC)

Our Sun article states that while it's a yellow dwarf, "its light is closer to white than yellow". So, in other words, it has a yellowish tint to it. SinisterLefty (talk) 03:06, 18 June 2019 (UTC)

Is there a source for that statement? ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:24, 18 June 2019 (UTC)

I don't see one, but I took it at face value. If that's inaccurate, it should be fixed. SinisterLefty (talk) 03:27, 18 June 2019 (UTC)

Finding a source, one way or another, would be the best option. Here's one from Stanford.[1] ←Baseball Bugs ^{What's up, Doc?} carrots→ 04:00, 18 June 2019 (UTC)

I read that as "the Sun is often called a 'yellow dwarf', but it's really white." Out of the visible spectrum, the Sun actually gives off the most light in green. --47.146.63.87 (talk) 06:03, 18 June 2019 (UTC)

Color of a black body from 800 K to 12200 K. This range of colors approximates the range of colors of stars of different temperatures, as seen or photographed in the night sky.

colour is subjective (and contextual), but one way to make it objective is to say that sun color is 5,777 Kelvin. Which translate as this (from black-body radiation), that is, in my eyes, slightly yellowish-white

Gem fr (talk) 07:07, 18 June 2019 (UTC)

I'm not altogether convinced by that graphic. You're right that 5800 K on that chart hits a yellowish patch (at least on my screen). But even a 5000 K lamp looks, if anything, slightly blue to most people, at least when used for indoor lighting. --Trovatore (talk) 17:54, 18 June 2019 (UTC)

The confusion may be due to that graphic not being the actual color of those objects, but rather their color "as seen in the night sky", so after passing through the atmosphere, which would diffract some of blues away, giving what remains more of a yellow hue. SinisterLefty (talk) 18:17, 18 June 2019 (UTC)

Rayleigh scattering is a small effect for objects high overhead, not enough to change their color significantly. --Trovatore (talk) 19:26, 18 June 2019 (UTC)

They didn't specify the angle. SinisterLefty (talk) 19:44, 19 June 2019 (UTC)

Actually, after visiting that page, I'm no longer so sure it's insignificant. Still, I don't think the OP was asking what color the Sun is when you can comfortably look at it; that's not a question you really need to ask the refdesk. You just go outside and look. --Trovatore (talk) 20:44, 21 June 2019 (UTC)

Not if they're color-blind. Also, since there's a range of colors, it would take many observations to determine the full range. And it's rare that you can comfortably look at the Sun with the bare eye. There's sunrise and sunset, but it might still be too bright then. There's fog and overcast conditions. And there're certain total eclipses, but that's dangerous as you may suffer eye damage when the Sun peaks out from behind the Moon. Dark sunglasses help, but may also change the color. SinisterLefty (talk) 00:21, 22 June 2019 (UTC)

The color white is by definition that color that you see when you're outside looking at an object that reflects all wavelengths uniformly. Your brain will adjust the white balance to make it so. Count Iblis (talk) 10:39, 18 June 2019 (UTC)

White balance has limits. Blood will never look white in full color vision (photopic). What blackbody is furthest from where your visual lobe can't white balance it to look white anymore? That is the whitest white blackbody possible. Now if you could do this in a holodeck and instantly raise the other wavelengths of that perfect blackbody to that of the brightest wavelength (one of the greens I think) wouldn't violet and red objects suddenly look brighter? If the green wavelengths are only 109% the brightness of the violet and red wavelengths in theory they'd get brighter but you'd barely notice if at all. Would objects with equal albedo between the world records of wavelength perception (at least 280-850nm) suddenly become so white they they suddenly look slightly green-tinged when you switch back to blackbody or is a blackbody of the right Kelvins already the whitest white the brain can perceive? Eclipse eyeglasses dim 100,000 times. Since the Sun is best photographed through a telescope at 1/125 to 1/1000 seconds or less to freeze the same effect that makes stars twinkle they make filters for cameras that dim only 10,000 times but those can damage your vision when looked through. If you were at the distance in space where the Sun was 100,000 times dimmer per cone (about 0.005 degrees) or whatever it is that doesn't saturate a cone but still bright enough for full color vision (so still bright by stars in Earth's night standards) then the Sun would look yellowish white (at least if you hold a rainbow of equally bright LEDs from 400 700 nm near it to tell your brain fuck you, stop white balancing) but from Earth it saturates all cones which would make it impossible to see any yellowness even if the brain didn't adjust white balance which it does. As the eye has microsaccades and averages brightnesses on the timescale of the persistence of vision the Sun probably can be more than 1/100,000th the square degrees of a cone cell before cones get saturated. Sagittarian Milky Way (talk) 13:57, 18 June 2019 (UTC)

Blood is fairly dark (nonreflective), so isn't going to look white, but does sometimes look black, as when viewed in dim light. SinisterLefty (talk) 14:17, 18 June 2019 (UTC)

Everything looks grayscale if it's dim enough (scotopic, too dark for cones to see anything). Then there's mesopic, rods not saturated yet but cones at the dim end of their scale. Thus blood doesn't look white or gray to the non-colorblind while the gibbous Moon is also fairly nonreflective (no glass bead retroreflection or complete lack of shadow hiding like full moon) and looks white at night when high up cause it's the brightest thing in view (sunlit ground) and close enough to white for the eye to white balance, unlike typical sunsets, blood, oranges, maple leaves, gas flames or monochromatic LEDs. Sagittarian Milky Way (talk) 15:49, 18 June 2019 (UTC)

FCS, guys, the OP just asked the color of the sun (which is, again, 5,777 Kelvin. Period.). look at your answers... Gem fr (talk) 09:53, 19 June 2019 (UTC)

The absolute color is certainly relevant, but since the OP is presumably here on Earth, it's reasonable to assume that they may also want to know what color the Sun appears to be on Earth (and they may not realize there's a difference). SinisterLefty (talk) 19:47, 19 June 2019 (UTC)

June 18

K9 breeding

Is it possible to interbreed different species of K9. I am aware that you can cross breed dogs but as Hyena's and foxes are K9s too,can you cross breed a large dog with a Hyena? I am not planning on doing this, I am merely curious if it is possible. has anyone tried this. The same goes for others in the K9 family, foxes, or wolves and hyena? Thanks Anton 81.131.40.58 (talk) 15:54, 18 June 2019 (UTC)

A quick Google search of the subject of what canines can cross-breed with, the answers are: wolf, yes; coyote, yes; fox, no; hyena, no. The reasons have to do with chromosome counts. And hyenas are not canines. They're more closely related to cats. ←Baseball Bugs ^{What's up, Doc?} carrots→ 17:23, 18 June 2019 (UTC)

I think it best to direct OP to crossbreed#Hybrid animals and canid hybrid. And Hyena. Gem fr (talk) 18:49, 18 June 2019 (UTC)

What about African Wild Dogs and jackals, can they be mixed with domestic dogs? — Preceding unsigned comment added by 81.131.40.58 (talk) 08:24, 19 June 2019 (UTC)

Jackals are several different species. There are hybrids between golden jackals and domestic dogs, see Jackal–dog hybrid, but the other species of jackal are far more distantly related, and I don't see any content about hybrids. African wild dogs are also much more distinct from domestic dogs than golden jackals, and I also see nothing about hybrids there. Someguy1221 (talk) 08:46, 19 June 2019 (UTC)

There are several dog wolf hybrids I believe dogs originated from the gray wolf and that is why it it easy to cross breed them especially with German Shepards and related breeds 64.222.180.90 (talk) 18:37, 20 June 2019 (UTC)

Electric engine speed or load monitor

I don't know what this is called, so I'm having trouble reading about it... Assume you have an electric motor. I doubt it matters if it is AC or DC. It rotates a spindle just like any other electric motor. Inside the motor there is a sensor. If the spindle is trying to spin faster than the motor is spinning, the sensor indicates that the spin is too fast or the load is too light. If the spindle is trying to spin slower than the motor wants it to spin, the sensor indicates that the spin is too slow or the load is too heavy. What would that sensor be called? I'm sure they exist, but I don't know the name of the sensor. 68.115.219.130 (talk) 18:43, 18 June 2019 (UTC)

Tachometer Andy Dingley (talk) 18:48, 18 June 2019 (UTC)

Types of Wheel speed sensor that may be used inside or outside electric motors include slotted-disk opto-isolators using Photodiodes and magnetic Hall effect sensors. DroneB (talk) 21:09, 18 June 2019 (UTC)

A bit off track from the question, but are there any motors that run on A/C? ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:41, 18 June 2019 (UTC)

most did, actually. Induction motor Gem fr (talk) 23:48, 18 June 2019 (UTC)

• Very few types of motor run on DC. Many run on AC. The two common types for DC are the permanent magnet brushed DC motor and the universal motor, which runs on AC or DC. Both of these use an internal commutator to convert the DC supply into an AC current within the motor, in phase with its rotation.

Rotary electric motors rely on some rotating magnetic field internally, generated by an AC current. The motor rotates at, or close to, some simple multiple of this frequency. The difficulty with AC motors in the first half of the 20th century wasn't in making them, but in controlling their speed. From the very earliest days of AC it was recognised that motors had great advantages in running from an AC supply, but they (mostly) would only run at one speed (Often a half or one-third speed option too, by some simple switchgear, but nothing to make a continuous change). DC motors, in contrast, could be speed-controlled almost from the outset. When these AC motors were used for the first electric railways, such as the Italian three-phase system, the motors would typically run at the synchronous speed, accelerating or decelerating to this speed quite effectively on their own, without any control gear being needed. This gave simple operation for freight services, but a rather rough (and speed-limited) ride for passengers, as the train drivers couldn't adjust their speed to the track conditions. Andy Dingley (talk) 01:56, 19 June 2019 (UTC)

I'm not sure exactly what you mean by the spindle is trying to spin faster than the motor is spinning, but governor (device) may be relevant. CodeTalker (talk) 03:49, 19 June 2019 (UTC)

Maybe a torquemeter? DMacks (talk) 12:31, 19 June 2019 (UTC)

It sounds like the motor and spindle are actually going the same speed, but you want to know whether the motor is driving the spindle or is a drag on it. The drag part could either happen if something else is driving the spindle, or if the inertia of the spindle keeps it spinning after the motor power is reduced. A strain gauge would tell you which is the case based on if it is in tension or compression. It measures microscopic stretching of the material (strain), which tells you how much of a torque is applied (stress). Or, alternatively, you could just measure the speed of the motor/spindle assembly, and compare that with the power being used by the motor. This info could be combined to figure out how much of a drag there must be on the motor (assuming it's working properly), or even if it was getting "help" from the spindle. SinisterLefty (talk) 14:27, 19 June 2019 (UTC)

That sounds like a shaft torquemeter (which isn't anything like a dynamometer). They're not usually very successful trying to use a strain gauge for this, as strain gauges are good at measuring 1-dimensional strain and this is more like a 2-dimensional shear. The usual measuring technique is more like a phase meter, measuring the torsion between two ends of a narrowed quill shaft. Put a pair of discs on the shaft, one with a radial slit, one with a spiral slit. Shine a collimated light beam parallel to the shaft and you'll see a narrow spot, once per revolution, where the slots cross. As the shaft twists, their relative position changes and the spot moves in and out radially. There are many variations on this idea. Andy Dingley (talk) 16:31, 19 June 2019 (UTC)

If a torquemeter and a dynamometer are nothing alike, the redirect from the first to the latter should be replaced by an actual article on torquemeters (or we could just redirect them to Torquemada and call it good). :-) SinisterLefty (talk) 01:20, 20 June 2019 (UTC)

The fundamental task of a dynamometer is to apply a braking load, secondly to record that force (or torque). The torquemeter only measures, it doesn't apply a brake. Andy Dingley (talk) 01:37, 20 June 2019 (UTC)

Solubility of salts in presence of other salts

Is the solubility of a salt like sodium chloride modified when potassium chloride is also present in various mole fractions up to saturation? A similar question for potassium chloride in presence of sodium chloride! A similar question for sodium chloride in presence of potassium bromide! How does the non-ideal nature of the mixture influence solubility of each salt in presence of the other? Thanks!--37.251.220.173 (talk) 21:25, 18 June 2019 (UTC)

If you mean "can I dissolve less NaCl in a KCl solution" then short answer: yes. Solubility#Solubility_of_ionic_compounds_in_water indicates why. You'll find more info in Category:solutions Gem fr (talk) 22:33, 18 June 2019 (UTC)

See also Solubility equilibrium#Common-ion effect catslash (talk) 22:43, 18 June 2019 (UTC)

How do the ionic strength and activity coefficients influence the mixed salts solubility? Are there any predictive models? --37.251.220.173 (talk) 15:46, 19 June 2019 (UTC)

The most basic model is simply to solve for conditions that satisfy all relevant equilibrium constants simultaneously. Someguy1221 (talk) 16:23, 19 June 2019 (UTC)

I see that strontium sulfate page says something very interesting re the rather low solubility of this salt in water, around 14 mg and the much higher but unspecified value of solubility in presence of alkali chloride like sodium chloride (uncommon ions). How can this situation be explained?--37.251.223.163 (talk) 22:10, 23 June 2019 (UTC)

Our common-ion effect article mentions several patterns for apparent exceptions. Sounds like there may be some chlorostrontium complex being formed but I’d have to pull my inorganic-chem text later this morning to confirm. DMacks (talk) 00:05, 24 June 2019 (UTC)

Looks like [SrCl₄]^2– is a fairly stable complex. See the oil-wells refs I just added to the strontium sulfate article for some details about the effect of chloride on SrSO₄ solubility. DMacks (talk) 04:15, 25 June 2019 (UTC)

I'm seeing the following as a lead ref that is at the root of many citation chains regarding chloride effects on the solubility: [2] DMacks (talk) 14:41, 26 June 2019 (UTC)

June 19

Black holes

What is the internal temperature of a typical black hole? And why? 86.8.201.134 (talk) 01:00, 19 June 2019 (UTC)

If I'm reading Black hole correctly, it's very close to absolute zero, and it has to do with a lack of internal energy. ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:06, 19 June 2019 (UTC)

You are not reading correctly. The low temperature mentioned (a few nanokelvin) is the temperature of its horizon, not its surface, and not the internal. The typical black hole sucks energy (=mass) out of the 2.7K background radiation more than it loses, and has tons (so to speak) of internal energy. Gem fr (talk) 09:47, 19 June 2019 (UTC)

My understanding is that black hole thermodynamics struggles to answer this very question, still open. Said otherwise: we cannot answer Gem fr (talk) 09:47, 19 June 2019 (UTC)

The issue is "where" in the black hole you look. As a corollary, consider the bottom of the ocean. Due to pressure, the water at the bottom of the ocean is forced to be as condensed as possible. When water is as dense as possible, it will be about 3C or 35F. The pressure is the primary factor in the resulting temperature. But, if you go up, pressure decreases and the temperature can be influenced by other factors. In stellar pressure systems like neutron stars and black holes, it gets very weird. Models of neutron stars are attempting to work out what happens when the pressure on matter is so high that electrons and protons merge to form neutrons. Then, everything is a neutron, commonly called neutron matter. What is the temperature of neutron matter? It is very close to absolute zero because any energy that exists is barely enough to keep the neutron from collapsing. In other words, the density of the neutrons inhibits energy which inhibits temperature. Inside a black hole, neutrons should collapse into quark matter. The energy keeping the neutrons stable is lost. With less energy, there is lower temperature. An expected model is that inside the event horizon, there is inward rushing matter that collapses around the singularity first as neutron matter. Inside that it collapses into quark matter. Inside that, it collapses further into a singularity, but bosons create a huge problem. They don't collapse (theoretically). So, is the singularity a mess of boson matter? If so, can it retain energy? What if bosons have nothing to do with it? What if it all collapses into string energy? Without mass, in the relative sense, what is the temperature of a singularity of pure energy? That makes no sense. Hopefully, it does make sense that there is a big hunch that once inside the event horizon temperature will drop quickly towards absolute zero. But, when you hit the singularity, temperature no longer has meaning. 12.207.168.3 (talk) 17:49, 19 June 2019 (UTC)

I'm not really following that logic, and our neutron star article says they have temperatures ranging from 10¹² to 10⁶ Kelvin, which is surely not 'near' absolute zero in anything less than the most cosmic sense. Wnt (talk) 04:15, 28 June 2019 (UTC)

June 20

Likelihood of death from influenza

Hello. As a general question, if a person contracts influenza, how likely is it that he or she will die as a result? An approximate answer is OK. I gather that people are more likely to die of this condition if they are very young or very old. Is that correct? FreeKnowledgeCreator (talk) 00:50, 20 June 2019 (UTC)

Quoting from our article Influenza, "Influenza spreads around the world in yearly outbreaks, resulting in about three to five million cases of severe illness and about 250,000 to 500,000 deaths." This implies a death rate of about 10% for those with "severe illness". The Spanish flu pandemic of 1918-1919 killed approximately 50 million people. It began in the final months of World War I and ravaged the planet. The virulence of the dominant strain of flu varies from year to year. The elderly are always very vulnerable especially if in poor health, but some strains seem to affect younger people more than others. On a personal note, my grandfather's first wife died in 1919 in that pandemic, and she was in her 30s. He remarried my grandmother a couple of years later, and I am the son of my grandfather's youngest child, my mother who was born in 1930. If it had not been for that pandemic, I would not be alive today. Every cloud has a silver lining. Cullen³²⁸ Let's discuss it 01:08, 20 June 2019 (UTC)

The different strains can have very different mortality rates, and the availability of hospitalization also has a big effect. Then there's difficulty in calculating just how many people actually have the flu each year, as mild cases and the many other conditions that produce flu-like symptoms are never distinguished for those who don't seek medical attention. And yes, the young and old, and people who are otherwise immune compromised or just in poor health are at much greater risk. Our article puts the average number of deaths each year in the US at 36,000-41,400, which would put death in the range of 1 out of every 1000 cases (the death rate is much higher for those hospitalized with the flu). Also see [3]. However, some strains can kill millions, such as the 1918 flu pandemic (Spanish flu) mentioned above. SinisterLefty (talk) 01:11, 20 June 2019 (UTC)

Just to build on the above, it seems that some strains of flu trigger what was known as a cytokine storm, but which now is known by the much less cool name of "cytokine release syndrome". In instances such as that, the healthy young adults experience much higher mortality as their own immune systems spin out of control - the 1918 pandemic in particular has been identified with this. Matt Deres (talk) 14:38, 20 June 2019 (UTC)

Anti-venom

How is anti-venom made, in layman's terms? I know they need to extract or milk snakes to get venom to be used in the creation of anti-venom, but how? Thanks Anton 81.131.40.58 (talk) 10:47, 20 June 2019 (UTC)

Inject a survivable amount of venom into an animal, perhaps a rabbit, and then collect and purify antibodies against that venom out from the rabbit's blood. Alternatively, collect white blood cells from the rabbit and screen for ones that secrete antibodies against the venom, then grow those cells in a laboratory to make as much as you want without wasting more rabbits. Read more at Antibody#Research_applications. Someguy1221 (talk) 11:07, 20 June 2019 (UTC)

Snake antivenom. DroneB (talk) 12:21, 20 June 2019 (UTC)

Why do news stories about someone who was snakebit commonly refer to it as the synonym "antivenin?" Edison (talk) 14:34, 20 June 2019 (UTC)

It's French. It's also called antivenene. Matt Deres (talk) 14:54, 20 June 2019 (UTC)

In some English-speaking countries "antivenin" is the word. It's not a kind of venom, so "anti-venom" looks like an error. --76.69.116.93 (talk) 22:34, 20 June 2019 (UTC)

EO says "antivenin" dates to the 1890s and that the trailing "in" may be a chemical suffix.[4] ←Baseball Bugs ^{What's up, Doc?} carrots→ 02:29, 21 June 2019 (UTC)

In Australia most of the anti-venenes are made using horses rather than rabbits. Treatment using this serum on a person for more than one episode can trigger an allergic reaction to horse serum on the second or third use. Hence most snake-handlers who get bitten try to not use the anti-venene unless/until it is absolutely neccesary. 49.197.107.84 (talk) 06:56, 21 June 2019 (UTC)

Are toothpastes exercises in branding?

I saw a new brand of toothpaste at the drugstore, parondontax, whose sole active ingredient is stannous flouride, or tin(II) fluoride. That's no different from, say, Crest Pro-Health, except maybe in price and manufacturer (gsk). What's the diff? 104.162.197.70 (talk) 11:56, 20 June 2019 (UTC)

Everything like that is an exercise in branding, more than anything. But stannous fluoride is a good thing, and not universal, even in fluoride toothpastes, as most of those still use sodium monofluorophosphate (MFP). Andy Dingley (talk) 12:13, 20 June 2019 (UTC)

I believe stannous fluoride is the least effective toothpaste and sodium fluoride in in the middle and sodium monoflurophosphate is the most effective of the 3 fluoride toothpaste ingredients available in the US not sure about non fluoride toothpaste but I do know in the US at least Crest mostly uses sodium fluoride and Colgate mostly uses sodium monoflurophosphate and stannous fluoride is in the sensitive products as it irritates teeth the least of the fluoride toothpastes 64.222.180.90 (talk) 18:33, 20 June 2019 (UTC)

Our articles on the relevant chemicals disagree with you about the relative effectiveness (for various meanings of that term) and have some citations to support. DMacks (talk) 19:16, 20 June 2019 (UTC)

Products are about more than just the active ingredients. Take alcoholic drinks. Alcohol is the only "active ingredient", but the other ingredients make all the difference in the experience. In the case of toothpaste, there's whiteners, breath fresheners, tartar reducing agents, flavors, etc. SinisterLefty (talk) 03:50, 21 June 2019 (UTC)

It's hard to recommend specific toothpastes without seeing the patient (so talk to your hygienist, this can actually matter). For most people, most good toothpastes are equally good. But there are some patients where there will be variations. If you suffer from a dry mouth (for whatever reason), then stannous fluoride is certainly preferable to the sodium fluorides, for its antibacterial effect compensating for that normally provided by saliva. If you suffer from staining after stannous fluorides (rare, but it can happen), then the better toothpaste formulations have ingredients to deal with that, which cheap ones might not. But it's a relatively rare problem, specific to some patients, and if you haven't got the problem, you don't need the solution. Andy Dingley (talk) 11:16, 21 June 2019 (UTC)

June 21

People with influenza drinking coffee

Hello. If a person contracts influenza, is it considered safe or medically desirable for him or her to drink coffee? FreeKnowledgeCreator (talk) 03:05, 21 June 2019 (UTC)

We don't do medical advice.

As to coffee and influenza, then advice is split anyway. Hydration is important, thus drinking something; but coffee can have a diuretic effect, thus the opposite. Paracetamol has been standard advice for years, although recent studies (Respirology, 2015) found no effect – but then placebos are still one of the most effective treatments for flu generally, even better than homeopathy. Many proprietary formulations of paracetamol or ibuprofen will include caffeine anyway, which has a useful effect for the rapidity of their effects on acute headaches, but no relevance to flu.

So no-one knows. And if they did, we wouldn't tell you here anyway. Andy Dingley (talk) 11:11, 21 June 2019 (UTC)

The dose makes the poison.41.165.67.114 (talk) 11:47, 21 June 2019 (UTC)

I wasn't asking for medical advice. I didn't say I had influenza, and I didn't say I planned to drink any coffee. It was purely and simply a general question, motivated by curiosity. There is no need to be rude. FreeKnowledgeCreator (talk) 04:40, 23 June 2019 (UTC)

Perhaps you could expound on what inspired the question? Something in the news, maybe? ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:25, 23 June 2019 (UTC)

The only reason I can think not to is that the flu can cause diarrhea, and coffee also can cause a bowel movement, so combining the two may be unwise from that POV. And I'm not sure how easy it is to keep coffee down on an upset stomach. SinisterLefty (talk) 18:07, 23 June 2019 (UTC)

Influenza can sometimes cause stomach upset, but "stomach flu" is a misnomer - that's caused by foodborne illness. Matt Deres (talk) 17:34, 24 June 2019 (UTC)

• A small study seemed positive about the idea: [5] But WebMD recommends against it as caffeine diuresis might dehydrate: [6] People suggest various odd teas that might be desirable (no medical basis): [7] Capsules are sold in the UK that contain caffeine with paracetamol (that's acetaminophen/Tylenol) supposedly to increase the pain relief. [8] On the other hand this news article links them to stroke [9]. We cover medical science, and lack of science, here, but we don't tell you what to do - you'll have to make up your own mind on that. Wnt (talk) 21:24, 25 June 2019 (UTC)

Long-term complications from microfracture surgery?

I heard somewhere that for professional athletes, complications may develop approximately eight years after undergoing microfracture surgery. Is there any literature out there which supports this? 67.83.118.216 (talk) 05:38, 21 June 2019 (UTC)

This paper apparently on 1200 patients claimed worsening results in 5% of patients, but no control group and honestly this is a very weird paper, I wouldn't trust it. I get the sense this paper was written to promote the practice. [This much smaller paper https://journals.sagepub.com/doi/full/10.1177/0363546508316773] reported 6 out of 17 patients seen over 5 years saw their symptoms get worse after surgery. [This seems to be a quite comprehensive article https://journals.lww.com/jbjsjournal/Fulltext/2007/10000/A_Randomized_Trial_Comparing_Autologous.2.aspx] and compares to a group treated with autologous chondrocyte implantation. They found that the "failure" rate increases from 2 years to 5 years, going from about 5% to about 23% in both groups. Yet another paper also found a proportion of patients who did worse over up to 10 years of followup, though they get extremely technical and don't have just one value to report. They also mention in their discussion another randomized trial claiming that the chance of backsliding seems to be higher for microfacture treatment than for other treatments over a ten year followup. Concluding, though, I think in all of these cases it may be hard to tell unless you really dig into case reports whether the complication is caused by something actually going wrong as a result of the surgery, and something just deteriorating as it was going to regardless. Seems to be a forgone conclusion that as a population, people getting either treatment are better off on average than people who got nothing, but I didn't look back to find the articles that support that claim. The last paper I linked does describe how many patients required additional surgery, so maybe that helps give an idea of what you're looking for. Someguy1221 (talk) 06:01, 21 June 2019 (UTC)

Immune system and infectious diseases

Are the chances of a person contracting a serious infectious disease influenced by the strength of their immune system? So for example, if 2 people were exposed to the same virus or bacteria which causes a serious illness, would the chances of one of them developing symptoms and being affected by it be influenced by the strength of their immune system? I guess my question is why is it that not everyone is affected when exposed to the same bacteria, virus or other disease causing agent? 90.210.250.247 (talk) 21:51, 21 June 2019 (UTC)

Yes, the general strength of the immune system is important, but there's also specific immunity to specific organisms. For example, if you've previously been exposed to a disease, or had a vaccine, then your body may still have antibodies designed to target that organism, which gives your immune system a significant jump-start on fighting off a new infection. This immunity tends to fade with time, and some infectious diseases, like the flu, mutate every year, so immunity doesn't last. Also, there's genetic immunity. For example, those with one copy of the sickle-cell gene are immune to malaria. There are many other examples. SinisterLefty (talk) 23:32, 21 June 2019 (UTC)

Not actually immune to malaria; from the linked sickle-cell article: "humans with one of the two alleles of sickle cell disease show less severe symptoms when infected with malaria."--Wikimedes (talk) 21:54, 22 June 2019 (UTC)

Occasionally weakness of the immune system can help (CCR5). It all depends on the pathogen and the person involved. Wnt (talk) 21:28, 25 June 2019 (UTC)

Why do people have fingerprints?

One reason I can think of is that fingers are too slippery otherwise so grabbing objects would be more difficult, but that doesn't sound convincing. In fact, those kind of wrinkles are visible on the rest of the inside of hands as well. Maybe it's simply "cheaper" (evolutionary wise) to do have wrinkled fingertips where it would cost more to have a flat skin, but then I'd like to know what's so different about my nose, or the upper side of my hands that don't have this feature. Joepnl (talk) 23:18, 21 June 2019 (UTC)

Your first instinct was right, it's for improving grip. Our palms are also used to grip things, so they have such wrinkles, too. SinisterLefty (talk) 23:27, 21 June 2019 (UTC)

Also for (or as outcomes of) improving touch sensitivity through friction, maintaining the health of the Epidermis, and helping the Epidermis and Dermis to cohere. See Fingerprint#Biology and Dermis#Dermal papillae.

(This being a reference desk, let's all remember to give actual references, people :-). Sometimes we might learn/remember additional facts ourselves as well as better answering the querants.) {The poster formerly known as 87.81.230.195} 2.122.177.55 (talk) 00:07, 22 June 2019 (UTC)

At least Fingerprint#Biology is completely wrong saying "These ridges may also assist in gripping rough surfaces and may improve surface contact in wet conditions" linking to an article that says the very opposite. "Scientists say they have disproved the theory that fingerprints improve grip by increasing friction between people's hands and the surface they are holding." ... "This confirmed that fingerprints do not improve our grip, because they actually reduce our skin's contact with the objects that we hold." Which is what I was thinking. Not convinced of health reasons either. Even without clothes, my upper legs happen to experience friction when walking, and they can do without wrinkles. Joepnl (talk) 00:41, 22 June 2019 (UTC)

That source sounds wrong, then. Car tires have treads to increase traction. This prevents hydroplaning, and something similar can also happen between smooth skin and a smooth surface, with a layer of liquid between them, like oil and/or water. And the area of contact does not have a direct effect on friction. The formula for frictional force specifies that it is only a function of the coefficient of friction and the normal force. And that coefficient of friction is reduced if a layer of liquid is between the two objects, which is why it's important to provide ridges that extend above the troughs containing the liquid, whether on a tire or a finger.

As for your legs, I'm guessing they aren't very hairy, as hair seems to serve the purpose (among others) of reducing friction. This is why many land animals have hairless toe pads, on an otherwise hairy paw, to increase traction. SinisterLefty (talk) 00:46, 22 June 2019 (UTC)

Even if that's true, what would my great (^50) parent need to pick up that's slippery where it would help to develop special wrinkles to hold it? Joepnl (talk) 01:07, 22 June 2019 (UTC)

50 generations ago (500 AD ?) there was all sorts of pottery and such which could be slippery when wet. But going back much further, how about a fish he grabbed out of a river, barehanded, and would like to eat ? SinisterLefty (talk) 01:13, 22 June 2019 (UTC)

Tyres do not generally get increased traction from treads - see Racing slick for example. The tread might allow the rubber to squirm and generate heat, and hotter rubber is generally stickier, but that's an eddect of heating not the tread. The main purpose of treads is to deal with water on the road/track, or to provide traction on muddy or rough terrain, where the tread can bite into the terrain.--Phil Holmes (talk) 09:46, 22 June 2019 (UTC)

I would consider racing tracks to be a "special case" where treads are not needed because they only drive when the track is dry and relatively clean. In "the real world", treads are needed to increase traction via all the mechanisms you listed. So, that is the "general case". SinisterLefty (talk) 11:57, 22 June 2019 (UTC)

Slicks are also used in rallying and on road circuits like Monaco. Tread does not increase friction - it can add mechanical grip, which is not the same. In some circumstances this can lead to better traction, but not in all.--Phil Holmes (talk) 16:09, 22 June 2019 (UTC)

Re: hair: where the friction takes place it's hairy like a baby. Joepnl (talk) 01:09, 22 June 2019 (UTC)

So hairless then ? SinisterLefty (talk) 01:13, 22 June 2019 (UTC)

Regarding the source, it does say fingerprints "...may allow water trapped between our finger pads and the surface to drain away and improve surface contact in wet conditions.". That I agree with. Note that the link was to a BBC report on the source, not to the source itself (like a technical paper). Unfortunately, reporters often get it wrong when reporting on science topics. SinisterLefty (talk) 01:13, 22 June 2019 (UTC)

Not surprisingly, other primates - gorillas, chimps, etc. - also have fingerprints, but the surprising one to me is that koalas have them too - https://www.abc.net.au/news/2018-07-01/biometrics-koalas-and-wood-glue-fascinating-fingerprint-facts/9920802?pfmredir=sm It's believed to serve the same purpose as in humans. Remember that when a koala grabs your smart phone. HiLo48 (talk) 00:20, 22 June 2019 (UTC)

A case of "sticky fingers" ? SinisterLefty (talk) 01:04, 22 June 2019 (UTC)

• Some research says fingerprints are used to feel the surface roughness of objects (i.e. enhance the sense of touch). The idea would be that a flat finger would need a high density of nerves to feel the change of pressure over the finger surface, whereas a wrinkled finger running over a surface can feel the bumps and drops and deduce roughness information without needing fine resolution. Here's an article but it's really super-technical. Tigraan^{Click here to contact me} 11:33, 25 June 2019 (UTC)

June 22

Skyrora

Any space enthusiasts could help me improve this article before it gets deleted again? Thank you very much! Ericdec~enwiki (talk) 03:58, 22 June 2019 (UTC)

Hey, sorry for the speedy delete - using facebook for a reference is never going to carry much weight. Although I have no expertise in the area I'll chase up some more refs and add some text and curate the page through. Cheers Hughesdarren (talk) 05:09, 22 June 2019 (UTC)

I found an interview with the CEO which I have added in. Alansplodge (talk) 08:28, 23 June 2019 (UTC)

June 23

Autoimmune encephalitis

Is autoimmune encephalitis a disease? On one hand, it can result from a number of autoimmune diseases, so I'm guessing "no" because I envision a disease causing symptoms/syndromes/etc., not other diseases. But on the other hand, Category:Encephalitis is a subcategory of Category:Inflammatory diseases of the central nervous system, so presumably encephalitis is a disease. I can't see how both of these ideas could be right, so I must be misunderstanding something. PS, note that Autoimmune encephalitis is a member of Category:Autoimmune diseases, but that's because I just put it there before asking this question. Nyttend (talk) 04:27, 23 June 2019 (UTC)

As with encephalitis generally, it's a symptom, but with a slightly specified cause. You could refer to it as a medical condition without confusion, I think. "Disease" has an incredibly broad definition that could include this. Someguy1221 (talk) 05:59, 23 June 2019 (UTC)

Does a woman who had 3 or more abortions have elevated cancer risk?

After reading the Wikipedia article on abortion, I am wondering if there is increased risk of uterine, cervical, or ovarian cancer after several abortions. Also, is it well established that these cancers are caused by hpv viruses? In the 90s, my biology PhD friend told me that many abortions leads to high likelihood of cervical and other cancers. Maybe he was wrong, or the science has changed?(He was in favor of abortion rights, by the way).One of the hypothetical causes I read recently about was abrupt hormonal changes after an abortion.Rich (talk) 16:50, 23 June 2019 (UTC)

HPV vaccine works at reducing cancer risk, but this doesn't mean that all these cancers are from HPV.

Also beware spurious correlation. For instance, having children late or not at all is known to increase breast cancer risk, and obviously women having several abortion are more likely to belong to this group. They may also have a lifestyle that expose them to more STD, including Papillomaviridae. Even if abortion by themselves are not the cause, this may cause correlation between abortion and cancer. Gem fr (talk) 17:37, 23 June 2019 (UTC)

Agreed. They may be having unprotected sex with strangers, and hence need multiple abortions. Thus, the multiple abortions aren't the source of the cancer, but rather the HPV and other diseases that will likely result from unprotected sex with strangers. SinisterLefty (talk) 18:02, 23 June 2019 (UTC)

Note also that anti-abortion activists have a known habit of spreading lies about the health risks of abortion. Someguy1221 (talk) 19:37, 23 June 2019 (UTC)

Spreading lies is usual tool of all activists. Pro-abortion activists have a known habit of doing it no less, starting with Roe Vs WadeGem fr (talk) 18:46, 24 June 2019 (UTC)

What "figures" is he talking about in your fifth item? ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:12, 25 June 2019 (UTC)

He's referring to NARAL's figures for how many women died each year as a result of not having access to safe, legal abortion. Tbh, I'm not sure if he's referring there to deaths from unsafe abortions or death from complications of pregnancy. I believe you could arrive at the figure they give (5-10 thousand per year) by making the naive assumption that all maternal deaths would have been prevented by abortion. Someguy1221 (talk) 02:51, 25 June 2019 (UTC)

If it's the latter, then it's indeed deceptive, although mothers dying after giving birth don't seem to be nearly as frequent as they were a century or more ago. ←Baseball Bugs ^{What's up, Doc?} carrots→ 04:32, 25 June 2019 (UTC)

• @Richard L. Peterson: A search of pubmed for abortion and uterine cancer, and abortion and cervical cancer found no relevant reviews linking abortion to a higher risk of those cancers. A search for abortion and ovarian cancer found one relevant article, which concluded A systematic review of 37 previous studies of the topic confirmed our findings that a history of incomplete pregnancy does not influence a woman's risk of epithelial ovarian cancer. It is hard to prove a negative but these results would suggest that the linking of abortion to increased risk of uterine, cervical, or ovarian cancer is an old-wives tale, or as Someguy1221 notes, intentionally spread misinformation.

PS: A note about my methodology: to weed out older articles, case-reports and weaker studies, I restricted my scrutiny of the pubmed hits to review articles published over the last decade. Given the quantity and pace of medical publishing this is unlikely to have caused me to miss any established links. Abecedare (talk) 20:28, 23 June 2019 (UTC)

Actually, in the case of causes of medical conditions it is often easier to prove a negative than a positive. That is, if no correlation is found between A and B, then A can't cause B. On the other hand, if there is a correlation, that doesn't necessarily mean that A causes B, as discussed above. SinisterLefty (talk) 17:52, 24 June 2019 (UTC)

In medicine, most published research findings are false anyway Gem fr (talk) 18:27, 24 June 2019 (UTC)

'Research findings" includes an enormous amount of exploratory research on small samples. And yes they should be redone with larger tests with careful checks on the design if the results are to be actually applied in real life, that is one reason tests of new medicines are expensive. That is quite a different matter from saying most reviews of a number of better done tests give wrong results. Dmcq (talk) 20:24, 25 June 2019 (UTC)

You seems to believe we can avoid that just redoing test on large sample. Well, no. just like shit, P hacking happens; it could even be more happening with big data and very large sample. For scientific disaster, you just need a very large listing of possible symptoms: just like in a classroom chances are 2 pupils are born the same day, you WILL find statistically highly significant correlations between some symptoms and literally anything, and you WONT be able to disprove it, and boom, you are toasted. You cannot detect which one are false, you just know that most of them are. Gem fr (talk) 21:11, 25 June 2019 (UTC)

Assuming you've actually read Ioannidis, you'd know that he stated this was primarily a problem with preclinical and early-clinical research, and he also discusses statistical methods for detecting and dealing with these issues regardless of where they occur. Using his findings to argue that we can basically ignore any results we don't like, because "most research is false", is simply using the ecological fallacy to avoid having to think. Someguy1221 (talk) 04:30, 26 June 2019 (UTC)

Sure, except your ecological fallacy claim is a straw man fallacy. And your use of "we" is also a fallacy: those who are doing research and lay people must not look the same way at a positive result. Scientists need them as a first step, while lay people turn into tin-folding lunatics when they don't ignore them. Gem fr (talk) 12:56, 26 June 2019 (UTC)

It is only well established that HPV cause almost all cervical cancers. However these is no evidence that HPV cause uterine, breast or ovarian cancer. Ruslik_Zero 20:30, 23 June 2019 (UTC)

June 24

Are the blinking lights at the top and bottom of a Boeing 747 shown correctly?

Hi! I redrew the left image below as an animated SVG for the navigation lights article. Instead of a generic plane, I decided to use a Boeing 747 as it's common and there is an existing 3-view line drawing of it in Commons. I could identify in the article all the lights in the original except the ones on top of and below the fuselage. What are those? I drew them at arbitrary positions on the 747. Where should they go? Thanks, cmɢʟee⎆τaʟκ 23:57, 24 June 2019 (UTC)

• 
  Original
• 
  Redrawn

This is a great question!

On technicality, you have drawn three different types of lights: the position lights, the beacon, and the anticollision light system. These terms are described, e.g., in 14 C.F.R. 91.209 "Aircraft Lights". Even more excruciating regulatory detail for Transport Category Aircraft can be found in 14 CFR Part 25 Subpart F §1381 Lighting, defining permissible light viewing angles and so on.

For a Boeing 747, the standard lighting placement actually depends on when (e.g. what year) the specific aircraft was built, and whether the standard lights were used. As described in this 2018 article in Boeing Innovation Quarterly, A History of Boeing Commercial Transport Flight Deck Lighting and Display Optics Innovation, a modern 747 uses LED-based lighting. Of course, after the aircraft is sold, the customer can technically move or refurbish the exterior lighting - and since there are so many aircrafts flying in so many variations, operating in different roles in so many different places, it's a sure bet that at least a few have some non-standard exterior lighting variations.

You can get official CAD 3-views from Boeing for the 747: Airplane Characteristics for Airport Planning. Self-evidently, the "747" model refers to multiple different airframe types with slightly different shapes, profiles, and variations in the "minor-engineering-details."

You can also browse a huge selection of photographs of different airframes from many angles at JetPhotos.com, an enthusiast website. For example, here is a lovely evening photo with the "top red light" illuminated on one of my very favorite 747 airframes, N747NA, who is of course SOFIA. Here's a nice evening shot of Lufthansa 747-830 D-ABYM with both top and bottom red lights shining, and the same aircraft with its rear strobe showing.

And here is even more regulatory guidance in the form of AC 20-30B Aircraft Position Light and Anticollision Light Installations, from FAA.

As a side-note - you have not drawn the landing light, the taxi light, nor any of the "dome" lighting on the aircraft that is used to illuminate the ramp during loading and ground handling.

In short summary - you have drawn the bottom light too far back: that light would normally go on the "flat" part, forward of the landing gear bays and should be colored Aviation Red; but this is just a minor detail, and you might possibly find subtle variations on real aircraft out in the wild.

Nimur (talk) 10:23, 25 June 2019 (UTC)

June 25

Anaphylaxis and cardiac arrest

What is the actual physical mechanism that leads to cardiac arrest and death in anaphylaxis? I know blood pressure drops and airways can swell, which leads to less oxygen reaching the blood. But how do these 2 things and other symptoms which I may have missed actually lead to a cardiac arrest? 90.194.63.148 (talk) 17:18, 25 June 2019 (UTC)

Presumably fluids leakage and airway obstruction lead to low oxygen supply to the heart, which eventually stops beating regularly i.e. fibrillates. Ruslik_Zero 20:30, 25 June 2019 (UTC)

Anaphylaxis#Cardiovascular has links to what happens Gem fr (talk) 20:46, 25 June 2019 (UTC)

Black holes

If and when the Big Rip happens, what will happen to black holes? Will they “survive” Rich (talk) 18:28, 25 June 2019 (UTC)

I don't think that is something our current understanding of physics can answer. But they won't survive forever - Hawking radiation will make them evaporate. --Stephan Schulz (talk) 19:25, 25 June 2019 (UTC)

@Richard L. Peterson: Very hard to say what will happen; we are talking about an event that may happen in roughly 22 billion years. The Big Rip article states that atoms, spacetime etc. will all be torn apart, so roughly speaking, black holes will not 'survive'. You also have to remember that this is hypothetical - the universe might end in a Big crunch, Big Chill, or several other possibilities, including religious ends to the universe. Even the cause of a Big Rip (Dark energy) is barely understood. Willbb234 (talk) 19:53, 25 June 2019 (UTC)

In a Big Rip scenario, black holes will lose all their mass due to accretion of phantom energy, see here and here for details. Count Iblis (talk) 15:57, 26 June 2019 (UTC)

June 26

DNA Replication

Help from biologists required:

File:DNA Replication, an introductory video.ogg

3' and 5' are positions on the ribose. The phosphate(s) come with the 5' but get attached to the 3' when nucleotides are put together.

I am in the process of generating a video to show the basics of DNA replication. The video will (in acceptable volume) be published in a relevant article of the en:WP.
As I am not sure that I understand the concept of 3´to 5´vs 5´to 3´I need some WP editor with specific knowledge to verify that my little film shows a correct process of replication.
Thank you for any help / critique and advise.
--Cookatoo.ergo.ZooM (talk) 13:48, 26 June 2019 (UTC)
PS: I may have to split the video into shorter, maybe 60" clips to achieve some reasonable quality, but that is temporarily irrelevant.
PS2: You may have to click twice; for unknown reasons, the fist click shows but a black window.

Our article didn't have a figure I wanted, so I numbered the one we had and put it at the right. Polymerases work by breaking off some phosphates and linking the remaining phosphate of a nucleotide to a 3' end, so DNA strands grow at the 3' end under nearly all situations where replication is going on. The strands form a double helix pointing in opposite directions. Oh ... and as for the video, I'm afraid you have to scrap it entirely. It's just not the way it works -- you don't have large regions of side-by-side "double helix" without the helix. Wnt (talk) 15:40, 26 June 2019 (UTC)

Besides, the nucleic acid double helix contains a major groove and minor groove of different widths Gem fr (talk) 16:35, 26 June 2019 (UTC)

Hi, User:Wnt and thank you for the advice. I will modify the design and resubmit. The first attempt at abiogenesis was a total failure.
And for all we know, the current attempt (executed in online reality) may be doomed, as well 😈
--Cookatoo.ergo.ZooM (talk) 13:07, 27 June 2019 (UTC)
PS: I will ignore that helices are not symmetrical and uneven gaps / grooves are the result. This is not an exercise in molecular geometry. --Cookatoo.ergo.ZooM (talk) 13:14, 27 June 2019 (UTC)

Obviously you have to decide what level of detail to include and what the academic level of your target audience is. One confusing aspect is that in the polymerase reaction, there are dozens of loose A/T/G/C diffusing into the active site and then the correct one attaches with the rest simply dissapearing. It's true that there are lots of available bases of all types, but either they should bounce in and out (with only the correct one sticking) or else only the correct one should ever come in. You've also lost the whole visual idea of the need for the polymerase activity, which as you note is important for getting the strands to build. As illustrated, it seems its role is just to get the correct base-pairing, not also for attaching the new base to the previous part of the chain. Maybe retain the backbone, so it can "bond to the backbone" once it pairs with the base? If the backbone is made of arrows (rather than just a tube), then you can even illustrate the antiparallel difference between leading and lagging and the directionality of the replication, which you mention and is a major idea. DMacks (talk) 13:57, 27 June 2019 (UTC)

Thank you, user:DMacks.
I like your suggestion of switching the tubular backbones to antiparallel helical arrays of arrows to indicate the 3´/ 5´ logics of leading (continuous) / lagging (Okazaki) strand replication. This seems intuitive visual semantics. I have to experiment how to achieve that, but that is my problem. I expect a spot of brain storming in my Gothically vaulted regular winebar next to our cathedral will provide divine inspiration (or, at least, medication for ensuing frustration) 🤢.
And yes, the A/T/C/G blobs floating in and miracolously evaporating is clumsy and dilletant rubbish. This needs to be tightly modelled. A spot more brainstorming.
Your comments have been very constructive. Muchly obliged. --Cookatoo.ergo.ZooM (talk) 16:10, 27 June 2019 (UTC)

Have you see the WP:Videowiki tool? Doc James (talk · contribs · email) 19:21, 27 June 2019 (UTC)

June 27

Hypertension, isolated

There is a disease called isolated systolic hypertension. But why there doesn't exist a disease called isolated diastolic hypertension? --It's gonna be awesome!✎Talk♬ 17:09, 27 June 2019 (UTC)

There is: [10]. And also there's isolated diastolic hypotension: [11], and isolated systolic hypotension: [12]. As for Wikipedia not having articles on all of them, some conditions are more common and/or more problematic than others, and hence more notable. SinisterLefty (talk) 17:29, 27 June 2019 (UTC)

Thanks for the impressive and excellent points!! --It's gonna be awesome!✎Talk♬ 18:43, 27 June 2019 (UTC)

Can likely be redirected to hypertension and a sentence or two written about it there. Doc James (talk · contribs · email) 19:22, 27 June 2019 (UTC)

Actinide Questions and Info needed

I'm writing a binder of every Fact, use and Compound of every element and I need some info on some Actinides if you could give some. I also have some questions to ask If anyone can help. I'd appreciate it. Porygon-Z (talk) 21:15, 27 June 2019 (UTC)

See actinide series. Then follow up with all the links and sources you find there. After finishing that, come back here with any further questions. SinisterLefty (talk) 22:11, 27 June 2019 (UTC)

Well I do have a question. How do we Know more about Cn than Es-Lr? Porygon-Z (talk) 22:51, 27 June 2019 (UTC)

You mean Cm (curium) ? SinisterLefty (talk) 22:46, 27 June 2019 (UTC)

No We know more About Cn Than we do Md, No, and Lr. I'm making a binder on the facts, uses and compounds of every element. Can you give me more info about Fm-Lr. Porygon-Z (talk) 22:51, 27 June 2019 (UTC)

You mean copernicium? Why do you say we know more about it ? Our article on it is about as long as the rest, and all are over 30k characters, with separate articles on the isotopes of each. SinisterLefty (talk) 22:56, 27 June 2019 (UTC)

Because we know more about an element that only lasts 5 seconds and has a compound (Cn) compared to an element that we only know its chemistry in solution and it oxidation states with no compounds (Md,No,Lr). I did go through each article even listing facts uses and compounds. I don't have much. Porygon-Z (talk) 23:18, 27 June 2019 (UTC)

Not sure. In some cases, they may not have been studied for chemical reactions, as they are dangerous and expensive to work with and there is very little benefit, since they have short half lives. The same applies to Cn, but somebody might just have happened to get a grant to study that one. There's also a theoretical island of stability, which may include Cn, leading to more study to verify if that is actually the case. SinisterLefty (talk) 23:28, 27 June 2019 (UTC)

But What about Mendelevium What do we know about it that I don't already have? Porygon-Z (talk) 23:34, 27 June 2019 (UTC)

We have this link to the chemistry of Md: [13]. SinisterLefty (talk) 23:38, 27 June 2019 (UTC)

It doesn't give much, but what little it does have, I already either have, don't care about, or don't understand. What else can you find? Porygon-Z (talk) 23:47, 27 June 2019 (UTC)

You should include that electron configuration diagram, and ask about those parts you don't understand. I'm not sure if there is any more info out there. You can try Google searches, but, as I said, such artificial elements are of limited use so aren't studied much. SinisterLefty (talk) 23:53, 27 June 2019 (UTC)

Do you have any idea what the Electrochemical Equivalent of Mendelevium even means? Porygon-Z (talk) 23:57, 27 June 2019 (UTC)

They have a link that attempts to explain it. I don't know anything about it beyond that. SinisterLefty (talk) 00:09, 28 June 2019 (UTC)

OK, then what about nobelium? What facts can you give there? Porygon-Z (talk) 00:16, 28 June 2019 (UTC)

Did you look at isotopes of nobelium ? Lots of info there. SinisterLefty (talk) 00:30, 28 June 2019 (UTC)

Lots of info on how to make it. What about its chemistry? Porygon-Z (talk) 01:04, 28 June 2019 (UTC)

They do have extensive info on decay processes, too. Same comments apply as above: "may not have been studied for chemical reactions, as they are dangerous and expensive to work with and there is very little benefit, since they have short half lives.". To give an analogy, there's lots of info on the speed at which various fish swim, because that's what they do. But not so much info, say, on how fast an elephant swims, as that would be a rare occurrence for them. So, rather than looking for that info, how fast an elephant walks is more relevant. Similarly, for unstable laboratory elements, the nuclear processes are far more significant than the chemical processes. SinisterLefty (talk) 01:14, 28 June 2019 (UTC)

Well that recycles into the question; What do we know about it ? Porygon-Z (talk) 01:54, 28 June 2019 (UTC)

June 28

chemistry reference

Are all the physical and chemical properties of matter governed by its chemical composition? Suyogya1 (talk) 04:23, 28 June 2019 (UTC)

No. See for example Phase transition, Allotropy, and Microstructure.--Wikimedes (talk) 05:19, 28 June 2019 (UTC)

@Wikimedes by chemical composition i just not mean proportion of atoms only, but also their molecular structure, orientation, configuration, bonding type, bonding strength, etc. because for a particular proportion of atoms there exist these fixed properties. see The topics referred by you are just having those properties i.e., allotropy is structural modification, microstructure is highly magnified structure.Suyogya1 (talk) 07:23, 28 June 2019 (UTC)

Yes: its chemical composition govern the physical and chemical properties of matter;

No: other things than its chemical composition also govern the physical and chemical properties of matter. Temperature for instance. Or electronic state. Many other.

And, in science, it is important to define properly what you are talking about, and to use common definitions. You cannot stretch the definition of chemical composition so as to include, say, effect of temperature on the molecule. Chirality (chemistry) give you examples of molecule with the very same chemical composition, but different properties. Gem fr (talk) 08:27, 28 June 2019 (UTC)

I'm trying to understand this from the Hybrid Synergy Drive Article

High gear (equivalent): When cruising at high speed, the engine turns more slowly than the wheels but develops more torque than needed. MG2 then runs as a generator to remove the excess engine torque, producing power that is fed to MG1 acting as a motor to increase the wheel speed.

Surely the speed is a function of torque at the wheels (overcoming friction), and you will not be able to do anything with a generator->motor that you couldn't do by changing the gear ratio? -- Q Chris (talk) 09:23, 28 June 2019 (UTC)

According to the article "the torque/speed conversion uses an electric motor rather than a direct mechanical gear train connection". They say the goal is for the engine to run at a single "optimal speed" without having to vruuum-vruuum-vruum up the gears like a usual car accelerating, or having to suffer losses at a continuously variable transmission. Wnt (talk) 10:27, 28 June 2019 (UTC)