:::::::OK, I shall rephrase my question then - Are they? --[[User:Jayron32|<span style="color:#009">Jayron</span>]][[User talk:Jayron32|<b style="color:#090">''32''</b>]] 17:53, 23 July 2020 (UTC)
:::::::OK, I shall rephrase my question then - Are they? --[[User:Jayron32|<span style="color:#009">Jayron</span>]][[User talk:Jayron32|<b style="color:#090">''32''</b>]] 17:53, 23 July 2020 (UTC)
::::::::And before you go digging, [[Allergic rhinitis]] is the most common allergy symptom, bar none. Unless you're prepared to argue that respiration doesn't involve the [[upper respiratory]] tract, I can't see how an actual honest-to-god respiratory symptom being the most prevalent allergy symptom can do anything but refute your assertion that respiratory symptoms are somehow less prevalent than other symptoms. --[[User:Jayron32|<span style="color:#009">Jayron</span>]][[User talk:Jayron32|<b style="color:#090">''32''</b>]] 17:56, 23 July 2020 (UTC)
::::::::And before you go digging, [[Allergic rhinitis]] is the most common allergy symptom, bar none. Unless you're prepared to argue that respiration doesn't involve the [[upper respiratory]] tract, I can't see how an actual honest-to-god respiratory symptom being the most prevalent allergy symptom can do anything but refute your assertion that respiratory symptoms are somehow less prevalent than other symptoms. --[[User:Jayron32|<span style="color:#009">Jayron</span>]][[User talk:Jayron32|<b style="color:#090">''32''</b>]] 17:56, 23 July 2020 (UTC)
:::::::::That seems to be true which deepens my curiosity. It seems upper respiratory symptoms are more common than lower respiratory symptoms or cardiovascular symptoms. Why is this? [[User:Clover345|Clover345]] ([[User talk:Clover345|talk]]) 20:40, 23 July 2020 (UTC)
== Inselberges and monadnocks are may not the same thing ==
== Inselberges and monadnocks are may not the same thing ==
Revision as of 20:41, 23 July 2020
Welcome to the science section of the Wikipedia reference desk.
The best answers address the question directly, and back up facts with wikilinks and links to sources. Do not edit others' comments and do not give any medical or legal advice.
As Shantavira says, there is no suggestion of knowledge or sentience. The kelp populations dispersed and evolved separately. The point of the genetic diversion marks the event. Interesting read though, thanks for posting Zindor (talk) 10:19, 16 July 2020 (UTC)[reply]
The seaweed doesn't "know" anything. The earthquake killed off the seaweed in one area, and other seaweed grew in its place. That new seaweed hasn't mixed with the the adjacent seaweed that wasn't killed off, so the two populations are genetically distinct. Iapetus (talk) 09:19, 20 July 2020 (UTC)[reply]
Stye#Cause reads Sharing of washcloths or face towels should be curtailed, to avoid spreading the infection. Can the infection be spread after the stye has healed? When can towels be shared again? I have heard 10 days from the stye onset, but I cannot find a reliable source on Google (some websites even state that styes are not infectious). --62.98.105.176 (talk) 07:52, 17 July 2020 (UTC)[reply]
Please assume that's not an issue (people already living together, or sleeping together, with bigger infection vectors, usually sharing towels notwithstanding the risk of an occasional stye). I'm asking for information to add to the article, unrelated to a specific case. --62.98.105.176 (talk) 09:36, 17 July 2020 (UTC)[reply]
To me it doesn't look like a request for medical advice, Bugs, and the OP specifically states that they're looking to improve the article. Can you prove that it is such a request? (Obviously not, and I'm not trying to be contrarian, I just think you're wrong.) {The poster formerly known as 87.81.230.195}
Also, Wikipedia has no policy or guideline that says that you cannot give out medical advice. For example, my medical advice is that you don't use Crystal Meth. It is bad for your health. We do have some restrictions, but they aren't a blanket ban on giving anyone medical advice. We aren't allowed to give dangerous medical advice -- no "injecting bleach cures coronavirus" or "stop taking your pills". We aren't allowed to claim that we are doctors or other medical professionals. Nobody connected to Wikipedia can take any responsibility for the results or consequences of any attempt to use or adopt any of the information presented anywhere on Wikipedia, including refdesks, talk pages, and articles. But we are allowed to give medical advice. --Guy Macon (talk) 14:18, 19 July 2020 (UTC)[reply]
COVID deaths on weekends?
Typical graphs of COVID deaths or cases like I see here: COVID-19_pandemic_in_the_United_States#Progression_charts, see "No. of new daily cases" and "No. of new daily deaths" show regular up & down teeth features. Is this because of reporting differences on weekends? Or are people actually dying less on weekends? I can imagine maybe fewer diagnoses on weekends, but more actual weekend deaths doesn't really make sense to me. Staecker (talk) 12:10, 17 July 2020 (UTC)[reply]
No. The Weekend effect article discusses the higher mortality of patients admitted for treated to hospitals on the weekend. I don't believe it is relevant to this question about the lower reported weekend deaths.
I thought "everyone knew" this 7-day period fluctuation was due to reduced weekend reporting, but I can't seem to find a good reference for that explanation. Hmph. -- ToE13:46, 17 July 2020 (UTC)[reply]
The first three sources aren't particularly useful.
#1, Reduced testing suggested as reason for weekend drop in confirmed COVID-19 deaths, discusses a 50% drop of both single-day deaths and new positive cases in Michigan on one mid-April Sunday compared to the day before, saying "... the Michigan Department of Health and Human Services says the lower daily numbers may be tied to reduced testing over the holiday weekend." That would explain the drop in positives, but not deaths, and no mention is made in the article of delayed reporting.
#2, Why the 'weekend factor' is affecting coronavirus reporting figures in Europe, deals with the Europe, saying, "there seems to be a lag over the weekend as the figures on deaths and hospitalisations work their way through the system, such that reporting on Monday is artificially low, while on Tuesday the figures seem high as they catch up with reality."
#3, Transient Drops In Reported New Coronavirus Cases: ‘Sunday Effect’, does address reporting in the US, but unlike the previous source which at least offers speculation, this one only makes note of the fluctuation without suggesting any cause. "It appears that every Sunday there’s a substantial decrease in numbers of confirmed cases from the previous day or the Friday prior to the weekend. A similar temporary decrease in deaths can be seen every weekend."
But the fourth source is on point, albeit for the UK, not the US.
#4, Understanding the data about COVID-19 related deaths, explains and contrasts DHSC and ONS statistics. The caption for slide #1 states, "The number of registered deaths reduces during weekends (and bank holidays) when deaths tend not to be registered." That is shown graphically in slide #2 which compares "ONS - Deaths by date of registration" with "ONS - Deaths by date of occurrence", showing a steady progression in the latter despite the weekend dips in the former.
I've been unable to find anything like that fourth source but for the US, most likely because "everyone knows" the dips are due to weekend reporting delays and few people feel the need to prove the obvious. -- ToE15:56, 17 July 2020 (UTC)[reply]
Why are there no cute robots which are shaped like plushies?
I can find some designs of them but they're not robots - they can't move on their own. I'm thinking about something like a cat robot that is fluffy and auto hug you.
Kazeita (talk) 20:26, 17 July 2020 (UTC)[reply]
I don't have any referenced source, but to me it seems immediately obvious that such a toy could (in rare circumstances, while unsupervised) be dangerous to small children/babies, who might get "auto-hugged" in such a way as to injure them, say by putting pressure on an eye. We could use input from an expert on Toy safety regulation. {The poster formerly known as 87,81.230.195} — Preceding unsigned comment added by 90.200.41.197 (talk) 22:03, 17 July 2020 (UTC)[reply]
See [ www.aliexpress.com/item/32924413933.html ], [ www.aliexpress.com/item/32895794973.html ], [ www.aliexpress.com/item/4000940862423.html ]. --Guy Macon (talk) 08:42, 18 July 2020 (UTC)[reply]
Cleaning might be a problem (although obviously soft toys often aren't machine-washable). Getting such a robot accepted for play with multiple kids from multiple families might be difficult. Proposed "soft robots" conceptualised for eventual use in elder care aren't designed like soft toys, they're made of vinyl that can be hosed down. Blythwood (talk) 21:09, 21 July 2020 (UTC)[reply]
NEOWISE comet visibility
For some reason and for several days already I can't see Comet NEOWISE in Warsaw, Poland, coors of observation are 52°16'12.5"N 20°55'51.1"E. I tried to observe at around 23:00 and at midnight, but see nothing except possibly Arcturus and a few major stars and planets. Light pollution or something else? 212.180.235.46 (talk) 22:08, 17 July 2020 (UTC)[reply]
If you're actually in Warsaw, or any other major city, then light pollution will not permit you to see the comet. You will need the sky to be dark enough at least to be able to see the Big Dipper, near where the comet is currently situated, and whose stars are roughly the same apparent magnitude as the comet.--Shantavira|feed me09:55, 18 July 2020 (UTC)[reply]
Neowise is expected to return in a few thousand years. It is possible that the people who have left Poland (or Europe, or even the planet) by then have turned off the lights prior to their extinction / diaspora.
The OP may, like myself in the UK, have been too far north to see the comet easily when it was a morning object, because in more northerly latitudes (compared to, say, the US) the summer Sun does not get as far below the horizon, so the twilight remains brighter.
The comet is now an evening object, and is moving night-by-night more perpendicularly away from the horizon, contrasted to its nearly horizontal movement when it was a morning object (see the diagrams in this Sky & Telescope article), so the OP (and I) can hope for better luck in the next week (cloud cover permitting). {The poster formerly known as 87.81.230.195} 90.200.41.197 (talk) 21:01, 18 July 2020 (UTC)[reply]
Returned to add – Yes! Have just observed it at approx. 22:10 UTC from a suburban setting (actually my upstairs rear bedroom window). Just visible to my rather suboptimal spectacled eyes with no dark adaptation, and an impressive sight in my rubbish 7x50 binoculars. Later tonight I'll take my 25x100s and tripod to a darker site in the unlit parkland 20 minutes' walk from my house. {The poster formerly known as 87.81.230.195} 90.200.41.197 (talk) 22:24, 19 July 2020 (UTC)[reply]
It seems that these bacteria are no specific 'stromatolite bacteria', but that many different bacteria and algae and varied associations of these can build stromatolites given some suitable conditions. And possibly these same bacteria and algae are found everywhere on Earth but usually they just don't build stromatolites. So the question becomes how does any bacterium reach some specific location on Earth? Surely carried by water: [[5]] "Water is one of the most important bacterial habitats on Earth. As such, water represents also a major way of dissemination of bacteria ...". And wind would disperse bacterial spores over huge distances given that they can stay alive over centuries and even millennia, see e.g. endospore. 2003:F5:6F0F:6500:38C7:928B:9AB4:495F (talk) 23:22, 18 July 2020 (UTC) Marco PB[reply]
Owls are thought usually not to soar and actually they hunt by flying low and locate their prey using rather their ears than their eyes. But they are apparently able to soar occasionally, as for example reported here: [[6]]. Did you observe a soaring bird that you think could have been an owl? I suppose that an owl will soar sometimes maybe to fly back home, or will take advantage of a bright full moon night and open landscape to hunt by sight. 2003:F5:6F0F:6500:38C7:928B:9AB4:495F (talk) 22:55, 18 July 2020 (UTC) Marco PB[reply]
I did observe a large bird that seemed to have forward-looking eyes, soaring low over a small ridge a little above the highest field (~1600 ft) before the sun set on a west-facing slope. It drifted about, never flapping, loitering in my vicinity before drifting off along the ridge. It was pale and had a small tapering (as opposed to fan-shaped) tail. I had no camera. catslash (talk) 23:33, 18 July 2020 (UTC)[reply]
Like this, but palerSo both pale, both frequent open country and both may be diurnal in the UK. The barn owl seems to have a very large face indeed, which makes the short-eared owl a better fit. It looked very much as in this picture, though paler. The wings were held somewhat back, not horizontally as in many soaring birds. It continually drifted about, never hanging motionless - perhaps conditions for soaring were not good, as neither the slope of the ground nor the wind speed were very great. Are there any non-owls this could have been? Or was it a soaring owl? catslash (talk) 00:28, 20 July 2020 (UTC)[reply]
The very last picture in the same article shows an equally pale short-eared owl, with the wings extended, looking very similar to the bird I saw. It seems likely that it was indeed a soaring owl. Thank you for your help. catslash (talk) 15:28, 20 July 2020 (UTC)[reply]
See Conjunction (astronomy). The external links include a site that will allow you to look up future conjunctions. If you know your astronomy, you might even be able to work out where those will be visible from, based on the provided celestial coordinates. Someguy1221 (talk) 12:27, 19 July 2020 (UTC)[reply]
Both are currently visible, with Mars rising around midnight in the Northern Hemisphere and Venus about 3 hours or so later: they're about 25° apart (say, 5 widths of your fist at arm's length).
For interest, Jupiter and Saturn are also visible, quite close together, for the whole night, Mercury rises around dawn, and both Uranus and Neptune are also visible if you know where to point a telescope. See here for a run down of this week's positions.
As to how often, Venus is visible for about 10 months of the year one side or the other of the Sun, and Mars easily visible for most of every other year (when it's not close to the Sun and thus up during daylight), so allowing for which side of the Sun they're on (as seen from Earth), I'd say they can be seen together (at night) for a total of about 5 months every other year (though that total is not one continuous period). Doubtless others can provide more precise figures, but working out exactly when these periods occur is complicated, because of course Venus orbits closer to the Sun faster than Earth while Mars orbits further away and slower than Earth. {The poster formerly known as 87.81.230.195} 90.200.41.197 (talk) 15:05, 19 July 2020 (UTC)[reply]
Every 2 decades is a great conjunction aka Jupiter and Saturn. Named for rarest pair amongst the planets known to cavemen/pre-1780s people, not brightness though they're still pretty bright. Mark your calendar, the best great conjunction in 4 decades is December 21 or so and the 2040 pass is probably even better cause got damn how many times can they occur near the Sun? They are approximately 4 zodiac constellations further back each time so the c. 2060 pass would be really good for the Northern Hemisphere if it's winter. It's almost 2020.97 AD now on a 2 decade timescale, and theirorbits are far enough for earth's POV to mimic the Sun's POV with some similarity so the 2 planets are relatively near now, as mentioned earlier.Sagittarian Milky Way (talk) 02:08, 21 July 2020 (UTC)[reply]
Now I remember, 2020 is very close as well, a 2060s conjunction (Venus and Jupiter?) is even closer, maybe even superimposing in a telescope from the right parts of Earth (or is that the one 1 or 2 centuries from now?, anyway make sure to look at it through a telescope in the 2060s. Sagittarian Milky Way (talk) 02:29, 21 July 2020 (UTC)[reply]
So, there are 40 billion (4*10^10) habitable planets in the Milky Way, and we wonder why none of them seems to have developed a civilization with noticeable presence in the galaxy. But what's so special about that, why is this even a paradox? This may seem like a large number, but think about probabilities. Consider something is protected with a password that's 8 characters long and consists only of lowercase letters of the English alphabet, with no numbers or special symbols. That's 26^8 = 208,827,064,576 (>2*10^11) permutations, a number 5 times larger. So, if it would take that many attempts to just crack a password that most programs won't even accept because it's too weak, what about having life not only arise on a planet out of nothing but also evolve into a civilization that traverses the galaxy? --Qnowledge (talk) 02:51, 20 July 2020 (UTC)[reply]
It is a paradox for those that think extraterrestrial intelligence should be common. But you are using the basis to support the idea that life and intelligence is unlikely. You can see the article for many explanations. Graeme Bartlett (talk) 04:37, 20 July 2020 (UTC)[reply]
The Fermi paradox is only a paradox in the sense that it is in conflict with the answer you get from the Drake equation, which is itself a Fermi approximation of the number galactic civilizations there are. In other words, the Drake equation is an attempt to define the parameters for how you would determine how many civilizations there are, and the Fermi paradox is only a paradox if you solve the Drake equation and get a number significantly different than "1". Drake's equation doesn't, of course, solve itself. You have to provide input numbers for all of the various variables and get an output number for it. Many of the inputs are known, but others are quite conjectural, such as " the fraction of planets with life that actually go on to develop intelligent life ", which makes an interesting way to frame the question of how many civilizations are in the galaxy, but not actually useful on calculating a reliable number. --Jayron3214:07, 21 July 2020 (UTC)[reply]
I find paradoxical how easily people forget the difference between "civilization" and "civilization with noticeable presence in the galaxy". Maybe 1) inter-stellar voyages are simply not possible and 2) all several thousand inhabited planets do lie so far from us that we cannot detect their radio signals. Our Galaxy takes at least 8 trillions cubic light years, so one hundred thousand civilizations will occupy eighty millions cubic light years each on average, that is the next one would sit some 4300 light years away from us on average. 2003:F5:6F0C:9500:ADC4:5DDA:DFDD:360E (talk) 19:51, 21 July 2020 (UTC) Marco PB[reply]
The Fermi Paradox also seems to make a lot of assumptions about the nature of interstellar exploration and colonisation. From the article:
given intelligent life's ability to overcome scarcity, and its tendency to colonize new habitats, it seems possible that at least some civilizations would be technologically advanced, seek out new resources in space, and colonize their own star system and, subsequently, surrounding star systems. ... If interstellar travel is possible, even the "slow" kind nearly within the reach of Earth technology, then it would only take from 5 million to 50 million years to colonize the galaxy.
This seems to presuppose some sort of "Star Wars" or "Star Trek" type scenario, where once someone has the ability to travel to and colonise another plant or star, it is then trivial to travel from there to yet another, and inevitable that someone would do so (and then do it again, and again, until the whole galaxy is colonised). But without easy and cheap FTL travel (which all known science says is not possible), that doesn't seem to me to be a likely occurrence. Establishing a colony in another star system would be phenomenology expensive (and risky), with little benefit to the homeworld. It would then likely take an extremely long time for that colony to develop the the stage where it would be to establish colonies of its own, and not a given that it would do so if it could. It therefore doesn't seem to me to be obvious that an intelligent civilisation "should" take over the galaxy, and therefore not a paradox that there is no evidence of one doing so. Iapetus (talk) 09:39, 22 July 2020 (UTC)[reply]
Those civilizations can be machine civilizations. Once self-replicating machines are developed, they should be able to spread from solar system to solar system. When they land on a planet, they'll build an entire copy of the civilization on their home planet. It's completely analogous to how life has colonized the Earth. Organic chemistry allows for the existence of self-replicating machines made out of molecules, such machines ended up appearing 4 billion ears ago and colonized the Earth. The machine civilization that ends up spreading through the galaxy does not necessarily have to do so for a rational reason. It may have degenerated into a dumb civilization. After it arose from the biological civilization it could have turned into a simple self-replicating infrastructure that is able to launch itself into space and seek out new planets to make more copies of itself without there being much of an intelligence or consciousness about this. Count Iblis (talk) 23:27, 22 July 2020 (UTC)[reply]
This is no argument: even machines will be constrained by the fact that if an interstellar voyage has to take two or three or five or ten thousand years no number of spare parts can help in keeping ship and crew working and flying. After eighty or hundred years all gears and articulations are worn out, joints and seals gum up, harden and clog and the chips in controllers burn out. You can at last plug a new card in if you have some left, but you cannot fill a space ship with enough spare parts if you want some place to be left for fuel. And beside that, in order to 'go forth and multiply, and populate the galaxy and subdue it' of course they don't need intelligence or consciousness, we are there to prove it, but they need a motivation, that is an instinct to do so, and where should they get one such in the first place? And third, a civilisation of machines would be dependent upon huge supplies of metals and energy even more than we are, and we have not enough of them in order to colonize the moon, let alone Alpha Centauri.
What causes the voltage gradient within a potentiometer to be linear?
An electric field that does not decrease with distance is difficult to create. The electric field (and force) between 2 point charges decreases exponentially as the distance between the two charges increases.
Electric Field = k × (charge / distance^2)
The difficulty of putting point charges into a configuration that does not have an electric field that decreases as distance increases can conflict with the linear voltage gradient within many resistors and capacitors. For example: a potentiometer typically has constant volts per distance when the resistive element is not tapered. Constant volts per distance requires an electric field that does not decrease with distance.
Volts = Electric field × distance
If static electricity were a collection of point charges at each end of the potentiometer’s resistor, the electric field would decrease exponentially with distance from each collection. An infinite sheet of charge is one of the few point charge configurations that can produce an electric field that does not decrease with increasing distance. [1] The (free) electrons within the potentiometer’s resistor are not exclusively located within two infinitely large sheet of charge. The ability of static electricity to apply constant force per distance on a point charge is evidence that static electricity does not use other point charges to apply force or store energy. Vze2wgsm1 (talk) 11:40, 20 July 2020 (UTC)[reply]
The question is not: “is the voltage gradient within a potentiometer linear?” I asked: “What causes the voltage gradient within a potentiometer to be linear?” Are the point charges within a potentiometer the cause of its linear (or logarithmic) voltage gradient? Vze2wgsm1 (talk) 20:26, 20 July 2020 (UTC)[reply]
It is just a voltage divider. Seriously. It isn't complicated. You really are overthinking this. Point charges have nothing to do with potentiometers. Neither does static electricity, electric fields, or any of the other unrelated concepts you are trying to drag into a simple explanation of a simple electrical component. See How Does a Potentiometer Work? and Electronics Basics – How a Potentiometer Works.
And, please, the electric field around a point charge in open space does not decrease with distance exponentially. It's a power law. If the independent variable is in the base with a constant exponent, it's a power law (in this case inverse square, as the exponent is -2). Only if the independent variable itself is in the exponent it's called exponential. PiusImpavidus (talk) 09:41, 21 July 2020 (UTC)[reply]
The material of the resistor modifies the field (because electrons in the material are displaced relative to the atomic nuclei). The charge displacement only happens within the material. If the side-walls of the material are parallel so that the cross-sectional area is uniform, then an approximately linear potential gradient results. On the other hand, if a point source and sink of current are embedded in a large block of the same material, then the current flow can spread itself out when far from either terminal, and a non-uniform potential gradient results. Shorter answer: it's the geometry of the resistive material. catslash (talk) 09:59, 21 July 2020 (UTC)[reply]
The material does not modify the field. Adding static electricity modifies the material, by adding like point charges to 2 ends of the material. There is a conflict between a uniform cross-sectional area of material causing a linear voltage gradient and point charges causing a linear voltage gradient. Point charges do not produce a constant electric field or linear voltage gradient unless the point charges are within an infinitely large sheet of charge. For example: for a single charged particle at each end of the resistor, the electric field would decrease with distance from the charge as a function of 1/distance^2, instead of being constant. Vze2wgsm1 (talk) 15:45, 21 July 2020 (UTC)[reply]
A potentiometer is, by construction, equivalent to two resistors in series who's values can change but who's sum is constant so your question basically amounts to "why is Ohm's Law true?" You should consult that article for a good starting point. — Preceding unsigned comment added by 2A01:E34:EF5E:4640:D8C7:92EB:2D96:8E8E (talk) 10:14, 22 July 2020 (UTC)[reply]
Why is Ohm’s law true?
Magnetic energy, (AKA a flow of electrons) does NOT normally exist without an inductor and a closed circuit. Static electricity can convert into thermal energy without an inductor or a closed (external) circuit. For example: an isolated charged capacitor can have leakage current. Therefore, volts can exist in an isolated capacitor or a resistor while the flow of electrons (current) and magnetic energy = 0. Vze2wgsm1 (talk) 00:52, 23 July 2020 (UTC)[reply]
Vze2wgsm1, for some bizarre reason you keep talking about electrical and magnetic fields when referring to a purely resistive device. Yes, everything with a difference in potential has an electric field, and yes, anything with a flow or current has a magnetic field, but neither are important in understanding potentiometers.
You appear to be more interested in talking about your pet theories than you are interested in learning from the many excellent Wikipedia articles that others are encouraging you to study.
The linear voltage gradient within a resistor with constant cross-sectional area is an observation and the linear voltage gradient can be used by linear potentiometers. The non-linear voltage gradient near dipoles is an observation. Please resolve the conflict between the non-linear voltage gradient within a dipole and the linear voltage gradient within a resistor. — Preceding unsigned comment added by Vze2wgsm1 (talk • contribs) 12:53, 23 July 2020 (UTC)[reply]
I would have said that there is no conflict to be resolved between two very different and not comparable situations: in the field around a point dipole on one side and a collection of millions of point dipoles on the other side, where on average the field as electrons sense it is uniform over the lenght of the resistor. By the way this is true not only for resistors but for any lenght of any conductor, for example for three miles of copper cable.. But I will follow Guy Macon's advice and better say nothing. 2003:F5:6F0C:9500:A088:A42E:9624:3880 (talk) 20:25, 23 July 2020 (UTC) Marco PB[reply]
B vitamins
Why are there different numbered B-vitamins (B6, B12, etc)? Do they all do the same thing? Additionally, is there a B-vitamin for every number? Heyoostorm (talk) 12:55, 20 July 2020 (UTC)[reply]
We have an article at B vitamins that might help you. There are eight of them recognized currently, but our article does a good job of explaining how complicated the history is and why some numbers are "missing". Matt Deres (talk) 13:07, 20 July 2020 (UTC)[reply]
{{ec}} Our B vitamins article introduces them as a set (what they have in common functionally--your second question), then lists them all (your third question) and what each one does specifically (your second question). I don't know why specifically they were all called "Bsomething" (neither why "B" nor why all as variants of that). DMacks (talk) 13:08, 20 July 2020 (UTC)[reply]
Wasn't it just that the B vitamins were recognized to be distinct substances later than the other vitamins? Some of the history is explained in two parts here and here. Another source is here. --174.89.49.204 (talk) 17:14, 20 July 2020 (UTC)[reply]
Some of them were once known by other letters; specifically G, H, M, and PP. So we can have B1=B, B2=G, B3=PP, B7=H, and B9=M. I don't think there's any other letter for vitamin B6. Georgia guy (talk) 17:39, 20 July 2020 (UTC)[reply]
Kind of. Vitamin § History goes over it. Thiamine was the first vitamin to be both identified as an essential micronutrient and isolated chemically, which is what led to the word "vitamin", from "vital amine". The thing is, what we now know as other vitamins, like vitamin A, had been identified from deficiency studies, but they hadn't been isolated, and there was an ongoing debate about whether there was a specific thing in the food that was a necessary nutrient, or whether it was a class of things, or if an anti-nutrient was getting added in processing. Eventually people started isolating more of them, except some went too far and classified as vitamins things we now know aren't essential, which is what happened to those "removed" B vitamins. --47.146.63.87 (talk) 05:13, 23 July 2020 (UTC)[reply]
Is it real that the most painful day after an operation is on the 3rd day?
Is it real that the most painful or dangerous day after an operation/circumcision is on the 3rd day? (probably it's based on an interpretation in the bible (Gen 34:25). But I'm not interested in the theological discussion of this issue but about the scientifical only). --ThePupil (talk) 17:00, 20 July 2020 (UTC)[reply]
I found some articles like this and this articles states the 3rd day is the worst of pain. On the other hand this huge research shows it's on the 1st postoperative day. While this article states it's usually worst on the 2nd day. A little bit confused. --ThePupil (talk) 00:48, 21 July 2020 (UTC)[reply]
It may depend on the nature of the trauma. Contusions and incisions may have different pain profiles, and amputations are a whole nother story. Your first and last links are about accidents and sports injuries, where timely applying a cold compress (ice pack) may help. Using a pair of scissors for a circumcision procedure may result in a somewhat blunt trauma. The second link mentions the effect of the fading of analgesic action (anesthesia and painkillers) supplied during and after surgery. Obviously, without analgesics the picture may (and likely will) be entirely different. The large study about post-surgical pain intensity does not actually state the pain is worst on the first day. --Lambiam15:01, 21 July 2020 (UTC)[reply]
It's a positive feedback loop, seeing as being aroused tends to induce an erection, but also the state of having an erection gives sensations that focus a man's mind on sex and make him feel more aroused. PaleCloudedWhite (talk) 22:48, 20 July 2020 (UTC)[reply]
Correct, and moreover it doesn't affect sexual desire either; it's not psychoactive. PDE5 inhibitors just act on blood vessels. Erections are hydraulic in nature; the corpus cavernosa fill with blood. PDE5 inhibitors make blood vessels with the requisite receptors more susceptible to dilating, which assists this process. Besides erectile dysfunction, they can also be used to treat pulmonary hypertension, and the article states they're under research for other conditions as well. Notably, sildenafil was developed as an antihypertensive; its effect on erectile dysfunction was discovered serendipitously in clinical trials. --47.146.63.87 (talk) 01:53, 22 July 2020 (UTC)[reply]
July 21
What disease was in the Greek camp at Troy?
Supposing Homer’s description of the plague during the Trojan war were accurate,(except probably not being caused by Apollo’s arrows), then given that it attacked “mules first and dogs”(Cowper) and soldiers later, and it occurred around 1200bce on Turkish coast, what diseases might it have been? The Plague, or malaria, or mumps or what? I should have said also that after 10 days the Greeks were concerned enough to have a big meeting about it. Does this information help enough to at least eliminate some possible diseases?Rich (talk) 04:48, 21 July 2020 (UTC)[reply]
Is there a webpage that shows which taxons live in and/or can live in place X or Y but not both?
So you can find out things like what animal ranges/gardening plants/native/introduced species are/could be in Boston but not DC. Also I've seen maps of "plantal latitude" and "plantal longitude" and range map dumps of thousands of taxa (and there are species in the same genus with very different range limits) but not a "plantal coordinates" ordered list preferably pruned to a less huge size to include only the most useful ones, like how fossils that appeared and/or extincted quicker than average and are common enough to become an index fossil are collected into lists for geological dating. Sagittarian Milky Way (talk) 16:12, 21 July 2020 (UTC)[reply]
All species are introduced species on a long enough time scale. Also, Boston and DC are not different enough ecosystems to have distinctly different flora or fauna around them. They will have much more in common than different; I would expect to find broadly similar flora and fauna, with perhaps a few small differences. --Jayron3216:52, 21 July 2020 (UTC)[reply]
Well introduced by humans, there's still some fuzziness as the original homes of some species if pre-man had never split from pre-chimps aren't well pinned down. That's my guess too, I'm wondering about the possible small differences. If red imported fire ants have a fairly sharp ecotone around the 10 Fahrenheit line (possibly north of Washington) then minor differences don't prevent intervening ecotones. Sagittarian Milky Way (talk) 15:40, 22 July 2020 (UTC)[reply]
Commercial bottled water has condensation near the top
I have bottles of water (think of a name brand) on a kitchen shelf at room temperature. It's summer, and some of these bottles now have condensation on the inside walls near the top of the bottles. Is this a sign of leakage or just water evaporating (quite a few dewdrops though) and condensing? Thank you. 104.162.197.70 (talk) 17:14, 21 July 2020 (UTC)[reply]
This is normal. If you place the bottles in a room where the temperature never changes (I noticed this in a clean-room where the temperature is controlled to well under a tenth of a degree) you see zero condensation. If the room temperature does change then whenever the air temperature is lower -- even slightly lower -- than the water, water evaporates from the (warmer) surface of the liquid and condenses on the (cooler) walls.
You might notice that when the opposite happens -- the liquid is cooler than the air -- you get condensation on the outside of the bottle. It takes a larger temperature change, though, because the outside air isn't at 100% relative humidity the way the air inside the bottle is. --Guy Macon (talk) 22:00, 21 July 2020 (UTC)[reply]
Additionally, see vapor pressure. The vapor pressure of a liquid is related (though not linearly) to the ambient temperature. Change the temperature, and you will change the portion of molecules in the bottle that are in the liquid phase and the vapor phase. So, increase the vapor pressure (via temperature), and you will have some of the liquid become a gas. Decrease the vapor pressure, and some of that gas will re-condense into a liquid. If the temperature is held perfectly steady, and the bottle contents were at equilibrium from the start, and you would not see that condensation. But, through temperature variations, you will change the equilibrium of the contents. If your kitchen is like my apartment, then in the summer, the temperature variation is greater than during other times of the year. My heating system can easily keep up with winter cold, but my AC can't keep fully up with summer heat, so during the day the temperature increases somewhat as the outside gets hot, and then decreases some as the outside cools enough for the AC to catch up. --OuroborosCobra (talk) 23:19, 21 July 2020 (UTC)[reply]
P.S. this is a really great question and a really great thought experiment! I might make a practice problem for my chemistry students modeled after this. --OuroborosCobra (talk) 23:20, 21 July 2020 (UTC)[reply]
oh ok. I guess the violence in Baltimore is about as bad as it is in Chicago, so that makes sense(tragically).Rich (talk) 04:58, 23 July 2020 (UTC)[reply]
Having provided a link in answer to a question, I note that Dr Richard Liversidge's article states: "He also carried out long-term work on the ecology of the springbok, and had the remarkable ability to predict rain, almost to the day, based on his observation of springbok behavior." Please can we provide more information. How do they do this and what is the behavior displayed? Thank you — Preceding unsigned comment added by 31.53.187.190 (talk) 08:35, 22 July 2020 (UTC)[reply]
Liversidge wrote an article about this in the South African Journal of Science, Volume 80.[7] Google Books does not allow me more than a snippet view, but what I can see is: "The springbok is an opportunistic breeder that has evolved a six month reproductive cycle that fits in perfectly with a six month rainfall periodicity." So it appears that he used his observations to predict the start of a six-monthly wet season. According to Animal Diversity Web, "The springbok generally mates during the dry season and lactates during the hot, wet season when resources are most abundant. Birth takes place in Oct-Nov, the start of the wet season."[8] --Lambiam10:44, 22 July 2020 (UTC)[reply]
According to Smithers (1983):[1] "Springbok are not seasonal breeders" AND "Skinner & van Zyl (1970)[2] showed that at all times of the year there were springbok rams capable of breeding and they suggested that the mating season was largely dependent on the physiological status of the females which was governed by their level of nutrition." AND "Springbok mate at any time throughout the year, the great bulk of the lamb crop being born during the summer in the summer rainfall areas (van Zyl & Skinner, 1970)[2]and in July in the winter rainfall areas (Skinner, Nel & Millar, 1977)[3] when ample green food is available."
I actually knew both Liversidge and Skinner well during their lives. Skinner dismissed Liversidge's idea that springbok could in effect predict the start of the rain season. It remained a point of dissension between them until Liversidge's death. Prof Skinner was the director of the Mammal Research Institute of the University of Pretoria for many years. Roger (Dodger67) (talk) 14:41, 22 July 2020 (UTC)[reply]
References
^Smithers, Reay H. N. (1983). The Mammals of the Southern African Subregion (1st ed.). Pretoria: University of Pretoria. pp. 630–631. ISBN0869795406.
^ abVan Zyl, J. H. M .; Skinner, J. D. (1970). "Growth and development of the springbok foetus". Afr. Wild Life. 24: 308–316.
^SKINNER, J.D., NEL, J.A.J., MILLAR, R.P.: Evolution of time of parturition and differing litter sizes as an adaptation to changes in environmental conditions. Proc. 4th Int. Symp. Comp. Reprod. Sydney: Aust. Acad. Science, 1977, pp. 39–44
Why are electric drills louder than electric cars?
I'm pretty sure my observation is valid ... it's complicated by the fact that I have to hold my drill closer to my ears in order to be able to turn it on than I am normally positioned near electric cars. — Preceding unsigned comment added by Hayttom (talk • contribs) 16:24, 22 July 2020 (UTC)[reply]
Sound intensity falls off with the square of the distance, and loudness, which is your perception of sound intensity, is complex and has many psychological, rather than physical, components. The connection between the magnitude of the sound wave and your perception of its loudness is not a simple physical law, and takes in many complex factors. A to B comparisons between different sound sources in terms of how loud you perceive them versus how intense the wave is are rather messy and not always intuitive.--Jayron3217:09, 22 July 2020 (UTC)[reply]
I understand and admire that response. But I actually still believe that electric drills are louder than electric cars, and if we could eliminate cars' tire noise, astoundingly so. Am I right? Hayttom (talk) 18:22, 22 July 2020 (UTC)[reply]
I don't know the why, but I did remark long time ago that some electric motors as in drills, coffee grinders and hair dryer are much noisier than for example electric motors in washing machines, forklifts, water pumps and professional lathes. I suppose the reason to be one or more of the following: noisy motors 1) make more revolutions per minute, 2) they have no ball bearings and 3) often they have a noisy gear change. I wonder also whether the number of poles and the number of phases could play a role. 2003:F5:6F0C:9500:EDEB:DDF5:E97D:77AA (talk) 19:18, 22 July 2020 (UTC) Marco PB[reply]
A typical electric drill makes a lot of noise because it has a motor that makes a lot of noise. The gear train adds noise as well.
Electric drills use brush-type universal motors. These motors produce noise as the brushes rub on the slots of the armature. You also have gear train noise. Electric drills use universal motors because they are far smaller and lighter than, say, induction motors.
Induction motors are far quieter, more energy efficient, don't wear out so fast, and run cooler, but they also have less torque at start up and are a lot heavier and more expensive for the same power output. Ceiling fans almost always use induction motors because nobody wants to listen to that universal motor whine or replace the brushes in the fan every time they wear out.
This is the wrong train. Washing machines have no soundproofing either but this kind of motors is intrinsically more quiet than that of e.g. a coffee grinder. Guy Macon has already given the reason. 2003:F5:6F0C:9500:A088:A42E:9624:3880 (talk) 18:49, 23 July 2020 (UTC) Marco PB[reply]
Any design has to balance lots of different requirements. A drill needs a lot of power rather quickly, must be small enough to carry relatively easily, and isn't expected to be run continuously for long periods of time while a car is expected to run long periods of time with the user enclosed within it and with little need (unless you are drag racing) for immediate full power. Couple these requirements with the relative price points of the two items and it may not make sense from a price or portability standpoint to make the drill any quieter. --Khajidha (talk) 04:30, 23 July 2020 (UTC)[reply]
Several good answers already. But also: Many household "electric drills" are actually hammer drills or even rotary hammers. The hammering function produces a lot more noise than simple rotation. --Stephan Schulz (talk)
July 23
Biochemistry of allergies
Why is it that life threatening allergies involving the respiratory or cardiovascular system is rare compared to Reactions involving the skin and/or digestive tract? Is it just because these areas are more exposed to allergens or is there more protecting the respiratory and cardiovascular systems? Why do many food allergies for example show skin and digestive symptoms but rarely the more life threatening symptoms as an example? Clover345 (talk) 11:43, 23 July 2020 (UTC)[reply]
Anaphylaxis, a potentially life-threatening allergic reaction if not timely and appropriately treated, often involves serious respiratory or cardiovascular symptoms. Together these account for most of the lethal cases. --Lambiam12:59, 23 July 2020 (UTC)[reply]
Also, don't confuse the popular term "allergy", meaning "any adverse reaction to something" and an actual allergy, which is a much more restrictive process in the body. To be an actual honest-to-god allergy, it must be initiated by an immune system response to something. Some things we call allergies may be more properly called things like Irritant contact dermatitis and Food intolerance. Secondly, MANY allergies cause respiratory problems; especially when the mode of the intaking the allergan involves breathing it in. Atopy, a medical term for a specific class of allergic reactions, includes asthma as a common symptom; indeed of the three main components of atopy (eczema, rhinitis, and asthma); two of them are respiratory related (rhinitis is inflammation of the upper respiratory system (nose and sinuses) and asthma is inflammation of the lower respiratory system (lungs)). --Jayron3215:34, 23 July 2020 (UTC)[reply]
The Wikipedia article on anaphylaxis has prevalence figures right in the lead. You're allowed to draw your own conclusions as to the tolerances of a concept like "rareness", but the information necessary to do so is already in the article you were referred to by Lambiam, and rather prominently. --Jayron3216:21, 23 July 2020 (UTC)[reply]
Your original question contains a presupposition that is not currently shown to be true. That is, when you state "Why is it that life threatening allergies involving the respiratory or cardiovascular system is rare compared to Reactions involving the skin and/or digestive tract?" you have not yet established that "life threatening allergies involving the respiratory or cardiovascular system is rare compared to Reactions involving the skin and/or digestive tract.". We can't answer "why" on a concept that is not yet itself shown to be commonly shown to be true. What is even your reason for supposing that? --Jayron3217:15, 23 July 2020 (UTC)[reply]
Ok I shall rephrase the question then - why are cardiovascular and respiratory symptoms less common than symptoms involving other organ systems in people with allergies? Clover345 (talk) 17:34, 23 July 2020 (UTC)[reply]
And before you go digging, Allergic rhinitis is the most common allergy symptom, bar none. Unless you're prepared to argue that respiration doesn't involve the upper respiratory tract, I can't see how an actual honest-to-god respiratory symptom being the most prevalent allergy symptom can do anything but refute your assertion that respiratory symptoms are somehow less prevalent than other symptoms. --Jayron3217:56, 23 July 2020 (UTC)[reply]
That seems to be true which deepens my curiosity. It seems upper respiratory symptoms are more common than lower respiratory symptoms or cardiovascular symptoms. Why is this? Clover345 (talk) 20:40, 23 July 2020 (UTC)[reply]
Inselberges and monadnocks are may not the same thing
I learned from a school textbook of geography that inselberges and monadnocks are not the same thing. I am greatly suprised to see the WP article of inselberg, which says that they are the same thing. Let me illustrate the comparison between inselberges and monadnocks according to the textbook:
This is one of the many terms that are used somewhat differently in the US compared with UK (and the rest of Europe). A quick glance through the available books on Google Books shows that some works recognise distinct differences, while others view them as synonyms. The place to raise this is at Talk:Inselberg, where you could open a discussion, but read through all the other discussions that look at this particular issue before doing that. Mikenorton (talk) 16:28, 23 July 2020 (UTC)[reply]
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