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	= November 13 =

	== Mitochondrial DNA questions ==

	# Please, in the least number of words and in the simplest way you can - Except for ATP production, what is the other main function of the Mitochondria?
	# What is the prevalence, in general, of known\defined Mictochondrial disorders? - What is the Ratio of Disorder\Births?

			= December 13 =
	I guarantee these are not homework questions; Thank you, Ben. ] (]) 03:03, 13 November 2014 (UTC)

			== What is the most iconic tornado photo ==
	: There are many different functions, really - biological structures and genes don't actually "know" what they are "for". The article ] does list quite a few of them. If I were going to answer I might have talked about ], but the article seems to prefer uncoupled energy production (as per heat generation in ]) as the more important second function, and I can't really argue it.
			{{hat\|Request for opinions}}
	: The article ] actually does list those stats currently, and cites its sources - 1 in 4000 births, but only about 15% of the diseases due to mitochondrial DNA proper. I haven't looked at such stats in a long time, but they sound plausible enough. ] (]) 04:04, 13 November 2014 (UTC)
			What photo of a tornado would you say is the most iconic? I'm researching the history of tornado photography for an eventual article on it and I've seen several specific tornadoes pop up over and over again, particularly the ] and the "dead man walking" shot of the ]. Which would be considered more iconic? ] \| ] \| ] 17:21, 13 December 2024 (UTC)

			:At the top of this page is a bullet point stating "We don't answer requests for opinions, predictions or debate": this reads to me like a request for subjective opinions. Perhaps you would like to consider what quantifiable and referenceable metric would answer what you want to know?
	::1. I never said or even clued that "Biological structures and genes know what they are for". I asked the question because I once read at a discussion here that Mitochondria have to '''main''' functions, 1 is ATP production and the other - well, that wasn't very clear from the text...
			:Presumably you also want only real tornadoes considered? Otherwise some might nominate the the twister from ], or from more recent tornado-related movies – ], anyone? :-). {The poster formerly known as 87.81.230.195} ] (]) 18:07, 13 December 2024 (UTC)
			:"Swegle Studios" has a couple of YouTube videos dedicated to the backstories of famous tornado photos and video; you might find them useful in your research. , . ] (]) 18:40, 13 December 2024 (UTC)

			:I googled "most iconic tornado photo" and a bunch of different possibilities popped up. I don't see how you could say that any given photo is the "most iconic". ←] <sup>'']''</sup> ]→ 18:57, 13 December 2024 (UTC)
	::2. I couldn't understand what you meant at "about 15% of the diseases due to mitochondrial DNA proper"; did you mean that 0.0000375 births (15%/4000) are Mitochondrial proper? ] (]) 05:07, 13 November 2014 (UTC)

	==Question About the Reversibility of Gene Therapy==
	I apologize for my ignorance in regards to this, but is gene therapy theoretically always (fully) reversible or not? ] (]) 03:46, 13 November 2014 (UTC)

	:As practically implemented, gene therapy is almost never truly reversible; it generally involves inserting bits of DNA into the cell; in theory this may be in a specific location (see ]), but in practice (as the deaths from leukemia attest) it can be less predictable. A clever approach might tend to pop out the preceding alteration, or be targeted to disrupt something that was added, but with varying degrees of success. It is however possible to make gene therapy that is designed from the beginning to be capable of being shut off; a laboratory mechanism in mouse studies involves using ] to control transcription of an added gene. In theory such control mechanisms could be arbitrarily elaborate and sophisticated. In practice, it is still far too rare to see gene therapy even attempted in even the most straightforward situations where it should help. ] (]) 04:11, 13 November 2014 (UTC)

	:Don't apologize for that!<BR>
	:At present gene therapy is not permanent, when the modified cells die the new ones don't have the therapy. So in a way it's reversible. However there is no direct way to reverse the effects, if you wanted to do that you would essentially need more Gene Therapy. So it's also not reversible. ] (]) 08:24, 13 November 2014 (UTC)

	== The Lactose has a sweet taste==

	Maybe that's what gives the sweet taste to the milk. Am I right? and does it raise the glucose in the blood - generally? (not for a medical advice, but to the facts about Lactose) ] (]) 06:14, 13 November 2014 (UTC)
	:Yes, and slightly old milk is sweeter since the lactose gets hydrolysed into smaller sugars, which are sweeter. Yes, it does raise glucose since it has glucose in it, but not very much. ] (]) 08:27, 13 November 2014 (UTC)
	::Thank you ] (]) 12:11, 13 November 2014 (UTC)

	==Thermodynamics properties of chemical substances==
	{{hat\|Incorrect use of ] - Otherwise not clear what is being asked. ] (]) 20:41, 14 November 2014 (UTC)}}
	If the chemical and physical properties of the chemical substances are always dependent on their valence and their molecular structure of the chemical substance, so that did the thermodynamic properties of the chemical substances to been defined by valence of this chemical substances?

	Valence of what chemical substances is always been much, the valence of the carbonaceous gases or valence of the alkalic vapour and acid vapour (chemical vapours)?--] (]) 09:59, 13 November 2014 (UTC)

	:It is unclear what you mean by valence? Valence is a property of an ] in a ] that refers to the number of ] that participate in ]. The way you are using the word here does not make sense. Perhaps you mean something different than what you are asking, but you have such a poor use of the English language it is hard to follow your questions. It may be best for you if you asked questions at a website where the other users spoke your native language. --]''''']''''' 11:35, 13 November 2014 (UTC)
	::I’m sorry for my English. I heard that the industrial use of all chemicals is always dependent on their calorie content which is always determined by the valence of these chemicals. Did the thermal properties of chemical substances depend on of the valence of these chemical substances?--] (]) 18:34, 13 November 2014 (UTC)

	:::When referring to 'valence', do you mean ']'? ] (]) 20:29, 13 November 2014 (UTC)
	::::I think, that ordinary chemical valence always gives an idea (concept) about the chemical and physical properties of chemical substances.--] (]) 11:17, 14 November 2014 (UTC)
	:::::Valence is a ] tool used in chemistry. It applies only to ]s, and not to all substances, and valence really only tells you how different elements will form bonds to other elements to form ]s. There is some alignment between the valence of an element and other properties of that element, but the effect is not truly causative, as you seem to imply. Valence doesn't ''cause'' an element to have its properties, valence is just a concept like ] which allows us to make specific predictions about specific ways in which elements come together to form compounds. For example, all of the elements in the ]s group have a valence of 1, and are highly chemically reactive; they all form very soluble salts, they all react explosively with water, etc. But having a valence of 1 does not ''cause'' them to be highly reactive. ] also has a valence of 1, and is relatively unreactive; it doesn't do anything remarkable in water, it doesn't form particularly soluble salts, etc. Valence as a concept is something taught to introductory chemistry students so the understand how to figure out ] and things like that, so they can reasonably predict what the formula for calcium chloride or sodium nitrate would look like. But as you get deeper into studying chemistry, it's a heuristic you'll leave behind as you get a deeper, more complex understanding of chemical bonding. --]''''']''''' 12:45, 14 November 2014 (UTC)
	::::::I believe, that the chemical valence always characterizes the electronic charge and the molecular structure of chemical substances, so I done this conclusion.--] (]) 14:36, 14 November 2014 (UTC)

	Note:''I believe, that in natural nature always been only once electronic charges (single electronic charges or charges of the electron pairs), so that I would argue that the valence always determines the chemical and physical properties of all chemicals, but this did not negate the fact, that in natural nature are always been a chemical substances which had complex valence - complex chemical substances and chemical substances which had simple valence - simple chemical substances.''--] (]) 15:00, 14 November 2014 (UTC)
	:''If in natural nature been other elementary particles except for electrons, in natural nature the negative charge could been exists as a positive charge, however, that in natural nature none done.''--] (]) 15:18, 14 November 2014 (UTC)
	::''Due to the fact that electrons did not change their electric charge in natural nature been an electric current!''--] (]) 15:25, 14 November 2014 (UTC)
	:::Under the influence of the forces of magnetism (electromagnetism) electric current (electrons) could change the direction of its motion in natural nature and electrical circuits, however, this did not negate what I told.--] (]) 16:04, 14 November 2014 (UTC)
	{{hab}}		{{hab}}

	== Gases and valence ==
	{{hat\|Incomprehensible material ] (]) 20:37, 14 November 2014 (UTC)}}
	''What natural gases in natural nature always had a lot, the natural gases which had a much valence or natural gases which had a small valence?''--] (]) 11:16, 13 November 2014 (UTC)

	:What do you mean by natural gases? Also, your use of English is so idiosyncratic that it makes it difficult for people to understand you well enough to know how to answer your questions. You should consider finding a website in your native language to answer these questions instead. --]''''']''''' 11:35, 13 November 2014 (UTC)

	::As the world industrial history always told, that at first was developed a mineral raw sources which had a low cost of raw material production, as well as had a natural raw sources material which had a low cost of industrial processing, so that I believe that natural gases which had a much valence was developed in the first place!--] (]) 15:52, 13 November 2014 (UTC)
	:::You appear to be using the word ']' in a different way than it is used in English, so that many of us can't understand your questions. Perhaps by natural gases you mean diatomic ], diatomic ], ], and ], but compounds do not have valence. If you really want to ask questions here, I suggest that you try automated translation from your native language into English, rather than writing the questions in your attempt at English. ] (]) 21:04, 13 November 2014 (UTC)
	::::As world economic history always told us, that the costly spending sources economic models always had economy of spending costs, so that the starting of costly spending sources economic models always had start from the low cost of raw sources materials and low cost of industrial processing of this raw sources materials, that’s why I believe, that the natural raw sources materials which had a much valence was developed in the first place! --] (]) 13:38, 14 November 2014 (UTC)
	:::::You are making what appears to be the same statement again, after being advised that it doesn't make sense, because you persist in using the word ']' in a way that is inapplicable in English. We can't answer your questions when we don't understand them. Please either find a reference desk service in your native language or use automated translation from your native language to English before posting here. If you continue to post questions that don't make sense, you may be ] from posting here. ] (]) 16:33, 14 November 2014 (UTC)
	::::::I think, that anyone practical model of the economics always done start only from a low cost.--] (]) 19:46, 14 November 2014 (UTC)

	{{hab}}

	== ] ==
	{{anchor\|cushing's syndrome}}
	A person suffering from Cushing’s syndrome will have symptoms that include rapid weight gain, particularly of the trunk and face (moon face) with sparing of the limbs. Why & how does the syndrome affect the body in this way?
	b.Could the consumption of hydrocortisone of 20mg daily to alleviate adrenal insufficiency also cause a “moon face” effect? {{unsigned2\|14:24, 13 November 2014\|113.210.35.128}}
	:Sensitivity to hydrocortisone, which is what we call medically-administered ], varies greatly from person to person (so it's not possible to give an accurate, simple answer to your question - the effects are too variable). The differential sensitivity of various types of ] (visceral and peripheral, among others - see some listed in that linked article) to the opposing effects of cortisol vs. elevated insulin levels that cortisol can stimulate, . -- ] (]) 20:06, 13 November 2014 (UTC)

	== Looking for further reading on cosmic body physics particularly comets/soft bodies type and collisions ==

	First is the bit I understand and what made me curious.

	Was looking at , which shows the Lutetia big side up and marks the circles of their craters.

	And then this one , which gives a sort of impression of two comets that collided and did not quite make escape velocity. So, I was think about the gravity and friction of when two bodies collide. Obviously the two had collided and caused a temporarily plastic surface, like, or even as, a wet blob, and eventually friction and other stuff brings it to a halt as the new single body.

	However... Would the ''internal friction alone'' be enough to bring the surface to a settling halt? I assume the external tidal forces, such as the pull of the sun, would be the cause of the surface in the absence of any absorber of the collision force. Can anyone say a subject with particular focus on cosmology that will tell me stuff like if stuff outside the suns area of effect actually settles into a constant steady surface some time after impact, as the Lutetias is, and stuff about how that settling actually works out there?

	I searched up stuff like collisions and gravity but of course it's a very specific item. There's probably not an article in it but aren't half of us wondering about comets and that today? :)<font color="green" size="2" face="Impact">~ ].].]</font> 15:32, 13 November 2014 (UTC)

	:The escape velocity of ] is 1 m/s, less than walking speed. If it formed through two bodies colliding, it was an incredibly minor crash. ] (]) 15:52, 13 November 2014 (UTC)

	::And it would also take a very long time for the two to approach each other at those speeds, maybe thousands of years ? ] (]) 16:36, 13 November 2014 (UTC)

	:I think you're looking for information about ].
	:On Earth, we use hydrostatic equilibrium to describe, say, water in a pipe; or oil-and-vinegar that have separated out into layers based on their different densities.
	:In planetary science, we can use the models and terminology of fluid dynamics to study all matter. Everything is a fluid on a sufficiently long time-scale!
	:One of the current elements in the ] is that the object's matter has enough ] to achieve hydrostatic equilibrium. That means two things: there's enough material - ''and it's made of chemicals that are soft enough relative to its own mass'' - to squish into a spherical object. This process can take thousands, millions, billions of years.
	:Comets are made of water and carbon dioxide ice, among others (methane and ammonia for some comets). They sometimes also contain a lot of other harder materials: to use the terminology of comet scientists, there are also "metallic" and "]" (rock-like) chemicals. Depending on which theory applies to any specific comets, those chemical compounds are ''primitive'' - they evolved directly out of stellar nucleosynthesis products - so they have never been subject to processes of geological evolution. That means that the iron in a meteoroid or a comet was never "refined" by heat and pressure; the "rock" and "dust" have never been subjected to the usual earth-style "]"/"]" progression; and although exposed to the harsh environments of space, there's not a whole lot of physical erosion action. These materials are kind of strange! Over a long time - ''billions of years'' - the materials have been subjected to direct, unfiltered stellar radiation, and extremes of temperature and heat. This actually can chemically change some of their materials. Over billions of years, exposure to sunlight has an erosive effect, softening "rock" and turning it into dust! (.
	:Add on top of this that the comet's elliptic orbit cycles it through a variety of solar distances, ranging across several ]. Methane and ammonia and water and carbon dioxide - all of which ''might'' be gravitationally bound to the comet - can turn from liquid, to solid, to gas, depending on the ] of the comet. So, one day the comet might be a bunch of sand and gravel that's glued together by rigid ice - and the next, it might be a swampy clump of wet sand and metal fragments! When that happens, the material can re-shape.
	:Last, but not least, there is a stronger force than gravity: '']. The comet, and all of its gas and solid components, are blasted by highly energetic ]. Some of the atoms become ionized. When this happens, the material in the planet is subject to electrostatic attraction - or repulsion - and the strength of these forces can be orders of magnitude larger than the attractive force of gravity.
	:''If there is enough matter,'' gravity will win: the self-gravitation of all these particles will, over the long run, cause the materials to smush together into a nearly perfect sphere. For a comet the size of Comet 67P/Churyumov–Gerasimenko, this hasn't happened yet - and very likely won't happen for a very ''very'' long time, comparable to the lifetime of the solar system. It will ''always'' be irregular!
	:Let me close with a pitch for one of my favorite books on planetary formation - one that doesn't pull any punches or leave out any equations! - it was ''written'' by the scientists who worked on the extrasolar planetary mission of the ] - and it has an entire chapter on comets and meteoroids; and another entire chapter on planetary models of hydrostatic equilibrium!
	:] (]) 16:42, 13 November 2014 (UTC)
	::Brilliant by User:Nimur. <font color="green" size="2" face="Impact">~ ].].]</font> 00:00, 14 November 2014 (UTC)

	== What is the farthest you can communicate with an unlicensed (and legal) radio? ==

	--] (]) 17:18, 13 November 2014 (UTC)
	:According to whose laws? --]''''']''''' 17:20, 13 November 2014 (UTC)
	:: Well, US, Europe, although I suppose there must be an international aggreement on this, so all countries will let the same wavelength free.--] (]) 17:35, 13 November 2014 (UTC)
	:::For starters, see ], ], and ]. maybe ] has some interest as well. ] (]) 17:42, 13 November 2014 (UTC)
	::::Note that it's not just a matter of what wavelength. Maximum transmission power, antenna size and other factors will be dependent on local laws. Also as those articles illustrate, it will depend on time of day and other factors. Additionally, "unlicensed and legal radio" is unclear. AFAIK, in many countries amateur radio operators can operate in frequencies and possibly with greater power without a specific licence for the radio, but they do need a licence themselves. ] (]) 18:04, 13 November 2014 (UTC)

	:::::For the purposes of this question... does the radio signal need to propagate wirelessly? ] (]) 19:19, 13 November 2014 (UTC)
	::::::I think I know what you're getting at, but ] says "Radio is the radiation ('']'') of electromagnetic signals through the ''atmosphere or free space."'' (emphasis mine) - Do you really commonly refer to signals sent through a wire as "radio signals"? ] (]) 19:33, 13 November 2014 (UTC)
	:::::::Actually I was thinking of a similar thing. Namely whether the OP was truly restricing the question to parts of the EM spectrum generally considered radio which includes some stuff also sometimes considered microwave and other things, but generally never stuff called light. Because high powered laser laws are still often limited albeit increasingly getting more stringent thanks to pressure from idiots misusing such lasers (and even then, some countries restrict readymade laser devices much more heavily than the diodes). Of course this illustrates another point, you can theoretically communicate quite far with lasers depending I think on atmospheric conditions and other factors. Possibly further than with an unlicenced radio even one designed to send to space (although I'm not sure). However there's no one to actually receive your line of sight signal somewhere in outerspace. ] (]) 13:44, 14 November 2014 (UTC)
	:If you are talking 2-way ] radio the ] article mentions some ranges. I do not see refs to support all the info though. I would imagine radios at sea would be more consistent in performance since there is no unpredictable terrain. <s>It mentions 111 km with 25 watt transmitter.</s> I went through some ads for handheld high powered 2-way radios and they went up to 5 watts. ] (]) 19:36, 13 November 2014 (UTC)
	::Looking around some more that article has to be wrong. mentions line of sight on a curved earth max range is 13.3 miles (21.4 km). ] (])
	:::I think the article might still be right. The marine VHF article says ~100 km for tall ships or antennae mounted on hills. Your recent link says 13 miles for a 100 ft antenna. Surely large commercial vessels will have much higher antennae, and consequently longer range, as described by the equations at line-of-sight propagation. (I did not check all the math, just saying that the two pieces of info are not necessarily contradictory) ] (]) 20:04, 13 November 2014 (UTC)
	::::Larger ships that travel far from land will also have access to ] (which is not limited to line of sight), or ] (or ]) satellite uplink (which is line-of-sight to an ] digital radio ]). ] (]) 20:07, 13 November 2014 (UTC)
	:::::Hmm. The OP really does need to give more specifics. mentions the different types of radios, their ranges and needs for licenses (in the US I am sure). If you are transmitting for an aircraft, up to 200 miles! So you have to buy or charter a plane too. Of course, you can walk into a store, buy a disposal cell phone and communicate via radio to anywhere on planet, no licence needed. ] (]) 20:31, 13 November 2014 (UTC)
	::::::In many countries, the mobile phone or its transceivers will however need to be appropriately licenced. (At the very least, in most cases the spectrum they are operating can only be used because whoever's network your connecting to paid the government good money to be allowed to use said spectrum. And said operator usually sets standards which you are required to follow, failing which they may ask you to stop using their network or even take legal action against you.) ] (]) 13:28, 14 November 2014 (UTC)

	:Technically you can communicate around the world, just use a low frequency. Looks like below 9khz is unlicensed (not certain though). But your bandwidth will be tiny. Some links to check: ] ] ] ] ] (]) 20:40, 13 November 2014 (UTC)
	::Technically, it is prohibitively difficult for an amateur on a limited budget to broadcast a strong signal at VLF or lower frequency. A ] ]. VLF and lower frequency transmitters tend to be operated by scientific researchers and by well-funded governments. ] (]) 00:17, 14 November 2014 (UTC)
	:::???? The OP is asking about unlicensed but legal transmitters. Hams (with legal licensed transmitters) have been doing EME (that's about all most half a million miles) since about the 1960 and all without a government grant of billions of dollars. For lower frequencies, a British and New Zeeland ham duo were able to communicate at 2 (two) watts, by careful frequency and phase matching and signal period. A technique, later adopted many decades later by ] in order to pull in the very weak 20 watt transmissions from Voyager one & two (and they added a bit of computerized statistical analysis as well, to speed things up, and to help filter out the signal from the background noise). Most unlicensed but legal transmitters are in the upper frequency range so don't travel much further than the visible horizon ''during time of normal propagation''. During time of tunnelling however, US police VHF communications have been hear in the UK. I have also received VHF from a guy whilst walking his dog on the shores of Holland who had only a 5 Watt transceiver but due to atmospheric tunneling he came in loud and clear. Sea water (being conductive) can create a dielectric wave guide taking the signal way beyond the radio horizon. So lets not hear any more of this “Technically, it is prohibitively difficult for an amateur on a limited budget“ nonsense. --] (]) 14:37, 14 November 2014 (UTC)
	::::Most HAMs aren't transmitting below 50 kHz - ergo, "VLF", "ELF", and so on. "VHF" and "VLF" are one letter and many hundreds of thousands of dollars of equipment apart. ] (]) 16:04, 14 November 2014 (UTC)
	:::::Most HAMs may not be transmitting below 50 kHz but some do and quite successfully without billion dollar grants. But this is with legal licensed equipment. Most no-licensed-required legal equipment (as asked by the OP) uses VHF and above.--] (]) 16:29, 14 November 2014 (UTC)
	]]]
	::::::I have no doubt that some amateur radio enthusiasts may ''try'' to transmit VLF; but they probably fail to generate very strong signals. This is what a VLF transmitter looks like: ]. That is not a grouping of several dozen different VLF aerials: all of those towers are the radiating elements for ''one single VLF transmitter''. The wavelength of the center-frequency is . So, if you wanted to build a crappy, inefficient, ''barely functional'' amateur-grade whip antenna (instead of one of these sophisticated multi-element radiator arrays that the Navy uses), you'd ''still'' need a piece of wire five miles long, and you'd need to somehow attach it to a tower that would be taller than the tallest structure ever built by humans. , the wire-runs alone would cost upwards of $60,000, but the engineering and construction costs would be ... a little more complicated to estimate! That's at ''24 kHz.'' Lower frequency radio, like ELF, corresponds to even longer wavelengths.
	::::::In March 2014, HAM operator claimed to transmit trans-Atlantic signal at 29.499kHz on WH2XBA. I would go so far as to say, ''this level of equipment is non-amateur.'' In fact, it is actually .
	::::::Let me re-iterate: I have no doubt that some amateur radio enthusiasts may ''try'' to transmit VLF; but they probably fail to generate very strong signal that would be suitable for long-distance propagation. It is ''much much much'' more efficient for a HAM to use an HF transmitter and use the ] effect to transmit over the horizon. ] (]) 18:36, 14 November 2014 (UTC)
	:::::::''Oh Boy!'' Allow me re-iterate. The OP is asking about '''Legal but unlicensed''' apparatus. What has '''power got to do with it''? See ]. The VLF image you referred to, is that high, because it is more efficient than it would be lower down, but a lower antenna is <u>still going to radiate</u>. Have you heard of antenna that are λ/2, λ/4, λ/8 high and in length etc. Right. So why oh why, does one ''need'' five miles of very expensive sleeved cable cable costing $60,000 like you linked to? It is up in the air -it does not need to be copper or have any insulation (use plain aluminum) and just a mile will do. $500,000 dollar towers ? Answer: String the antenna from tree to tree. If one has to have all ones teeth veneered by a dentist because one drank too much coke and soda pop as a child, then in comparison, the cost of an amateur VLF antenna and associated equipment is hardly astronomical- is it? -Finally, the OP asks about '''Legal frequency but unlicensed'''. Most frequencies above 9 kHz have been allocated by the ]. So in answer to the OP's question its about 3800 miles in normal day/night conditions with current practices; unless one is doing EME work but one will probable require a license for that in many countries as the side lobes could cause interferance. See and I quote:.--] (]) 21:25, 15 November 2014 (UTC)

	:::::::PS. Do you know what a whip aerial is and why they are used, together with their efficiency and suitability in the right application? You say “''barely functional amateur-grade''”? Look at the specs and compare them to commercial (cheap (?) and cheerful) whips that cost an arm and a leg. Then see if you can find the fallacies you're using from this ]. Just asking (;¬)--] (]) 21:59, 15 November 2014 (UTC)

	:The article you really need to read is ] and the short answer is several thousand miles under ideal conditions. For the purposes of this post I am assuming the OP is referring to unlicensed UHF hand-held transceivers that operate near 460 MHz in most countries (where they are legal). ] (]) 14:16, 14 November 2014 (UTC)

	:There are also some frequencies that have unlimited radiation regulations. 13.56MHz used to be a frequency that was chosen for certain equipment because it wasn't regulated. --] (]) 00:05, 15 November 2014 (UTC)

	== Why are we able to see light from almost the time of the big bang, should it not have got passed us? ==

	I know that the further away an object is, the further back in time you're looking at that object, it's simply because light takes time to reach us, and as a result we are able to see objects that are over 10 billions years now, to almost to the time of the big bang itself. The question I have is how come we are able to see that light given that everything started from a single point and that everything escaped from that point, and given that light goes faster than us, us made of matter, that light should have passed us almost right from the beginning and should now be impossible to see, so my question is why are we able to see light that came from almost the time of the big bang given that that light should be out of reach?
	] (]) 19:55, 13 November 2014 (UTC)

	:That is because space is glowing like a cooling ember. We cannot see the fire before the ember though. ] (]) 20:21, 13 November 2014 (UTC)

	::That doesn't really answer the question. Vacuum or space can not radiate light (even if you had the energy, where would the momentum go?). So ''what'' is glowing? ] (]) 21:44, 13 November 2014 (UTC)

	:::You are taking my metaphor too literally, I mean that even though it's not the honest truth, space itself may as well be glowing. The CMB was caused by the gas in the early universe cooling down. However, the rate of expansion out-paced the speed of light, and so the light from the glow is delayed. It is effect as hearing a lightning strike sometime after the matter, due to the difference between the speed of light, and speed of sound. ] (]) 01:04, 14 November 2014 (UTC)

	:First, it's not accurate that everything escaped from a point. A better analogy is that of an expanding balloon, with two dimensional creatures living on the surface of the balloon. To the 2D creatures, there is no third dimension. Their universe is expanding, but there's no point in space that everything is escaping from.
	:We can see almost to the Big Bang because at that time, we were moving nearly at the speed of light relative to the point we now see. The speed of light was so close to the speed of expansion that light only managed to catch up after 14 billion years. --] (]) 21:55, 13 November 2014 (UTC)

	:See ] for why light got left behind. ] 23:21, 13 November 2014 (UTC)
	::No, inflation is not really it. The balloon analogy is better. Imagine a constantly growing balloon (ok, there is some inflation ;-). We are living on and looking along the surface of the balloon in this reduced dimension. But no matter how far you look, there is always a piece of the balloon that is that far away, and from which light has travelled for a corresponding amount of time. --] (]) 00:04, 14 November 2014 (UTC)
	:::OK, point taken. Also, inflation happened before photons of light came to exist, and long before there were stars to shine, so the balloon started partially inflated. Perhaps a constantly stretching flat rubber sheet would be a better analogy if you believe that space is flattish. ] 00:27, 14 November 2014 (UTC)

	Bowlhover: I agree that matter was going at almost the speed of light at the moment of the big bang but now we are going much slower, it seems to me that the light from the big bang should have passed us long ago.

	Plasmic Physics: I agree that the CMB (Cosmic Microwave Background) is like the amber of the "explosion", an ambient light all around us that came from the big bang, but unless I'm mistaken, what we are actually seeing are very old galaxies that existed almost at the beginning of the universe, and again, how come we can see them, how come the light has not passed us and make them impossible to see???

	Stephan Schulz: the balloon analogy seems to best answer to my question; both me and the far away galaxy are moving apart, that means that light has a longer distance to travel, which allows me to see further in the past. It seems like a race condition, the speed of the expansion of the universe against the speed of light. Would be nice to get details on that.
	] (]) 22:14, 14 November 2014 (UTC)

	:See ] for details of the race. The expansion is currently ]. My point was that space had a head start. Matter as we know it (three states of atoms) didn't exist immediately after the ]. ] 22:28, 14 November 2014 (UTC)

	:Joc, the thing to understand is that the Big Bang didn't happen at a place. From our perspective, it happened at all places. All of space originated from the Big Bang, and consequently, ''all of space'' was filled with hot plasma in the initial moments after the Big Bang. In essence, when we look deep into space in one direction and see the cosmic microwave background, we are seeing what the after effects of the Big Bang looked like in that particular location a long time ago, and when we look in a different direction, we are seeing the after effects of the Big Bang ''somewhere else'' a long time ago. The Big Bang affected all of space, so if you look a great enough distance in any direction, you'll eventually see light that originated from the era shortly after the Big Bang itself. And the light you'll see reflects the impact of the Big Bang on that specific region of space far, far away (it's nearly the same in all direction, but people who study the ] can gain big insights from small difference depending on where you look in space). Also, the cosmic microwave background was created by the glow of ], a side-effect of the universe cooling after the Big Bang and forming the first atoms (instead of ionized ]). It predates the formation of galaxies and stars. ] (]) 23:07, 14 November 2014 (UTC)

	::That it happen in "all places" implies that the universe is infinite, that also implies that light has an infinite amount of space to travel, and so it implies that we could look an infinite amount of time in the past, even before the big bang! Now I know that's wrong, but I don't know how it's wrong. I'm NOT interested by the CMB, what we measure is it's temperature and it glows everywhere; what I'm interested is that I read that we can actually see galaxies from very near the time of the big bang, and that we can see them clearly enough to be able to tell they they are "primitive", that they didn't have the time to form structures such as spirals for example, this is not the diffuse light of the CMB but light from a very precise point in space and time, the thing I don't understand is how those photons didn't get passed us since they are faster than us, given that everything came from the same point (if everything is moving away, reversing the time arrow, implies that everything came from the same point).

	:::The universe may be infinite, or it may simply be far, far bigger than the part of it that we can see. Either theory is consistent with ] and the ] as we know it. The ] makes many things confusing, but lets ignore that for a moment. Ignoring expansion, we would assume that the oldest galaxies formed ~13 billion years ago, in a region of space ~13 billion light years away, using matter and energy the Big Bang left in their local region of space. As far as we can see, the Big Bang left a nearly uniform density of matter everywhere, and it did so as far back in time as we can see. In practical terms, that's what it means that the Big Bang affected all of space, it deposited nearly uniform matter everywhere we can see at the very beginning. That may continue literally forever (an infinite universe), or it may stop somewhere beyond the ] that we can see, but either way all of space for as far away as one can choose to look, is filled with matter. Incidentally, the CMB is the limit of how far one can look. At that point you are seeing the glow of the Big Bang, and no light older than the CMB survived.

	:::For a slightly more nuanced description, that includes expansion, one would say that the earliest galaxies formed ~13 billion years ago in a region of space that is now ~40 billion light years away. The extra ~30 billion light years is associated with the expansion of space, but the light only traveled ~13 billion years to reach us because at the time it departed the two regions of space were much closer. Even accounting for expansion though, the far away region of space 13 billion years ago already had a similar density of matter as the region of space we presently live in had 13 billion years ago. The Big Bang deposited matter everywhere we can see during the very earliest moments of time (e.g. ]), well before those early galaxies formed.

	:::To return to the balloon analogy, the universe is like the surface of a balloon, and the density of matter can be thought of as like the thickness of the rubber. As the balloon expands, all points get farther away from one another and the local density of matter (i.e. rubber) decreases. The universe stretches and thins. However, the balloon always had rubber everywhere, it was created that way. No matter how you shrink or expand the balloon, there is no point in time where the rubber vanishes, it simply becomes more or less dense. On cosmological scales, the matter in the universe is the same way. The instant of the Big Bang created the universe (i.e. the balloon) with matter everywhere. The matter was then stretched and expanded, becoming less dense, but there was no region of space (as far as we can see) that ever lacked for matter. ] (]) 20:23, 16 November 2014 (UTC)

	= November 14 =

	== All the different dimensions ==

	Do I understand correctly that we, you and I (and everything) are present in all the dimensions at once? Sometimes people talk about something coming from another dimension as though it came from a different universe whereas I have always thought of dimensions as being something we have a position in. Thus instead of coming from a different dimension, some object or creature might come from a different ''position'' within that dimension to our position in that dimension and thus become observable to us? Is that wrong? --] (]) 05:21, 14 November 2014 (UTC)

	:Yes, yes, no. ] (]) 05:48, 14 November 2014 (UTC)
	::Is it so simple? Is ] a dimension? Am I currently "present" at all points in time? ] and ] might be of interest when thinking about this question. ] (]) 16:51, 14 November 2014 (UTC)
	:::Yes, ] is normally considered a dimension, but behaves differently than the other dimensions, for reasons that cannot be explained in current physics. When something is said to have "come from a different dimension", it usually means that it is said to have come from a higher-order spatial dimension, presumably a spatial dimension with full extension that we cannot observe. The universe that we can observe consists of three spatial dimensions and time. Some Theories of Everything have various additional dimensions that are "rolled up". So if something really has come from a dimension beyond the three that we can observe, it is a matter of terminology or philosophy whether it comes from another universe or an aspect of this universe that we cannot observe. ] (]) 17:07, 14 November 2014 (UTC)

	:::Yes, yes, no to your questions also. ] (]) 03:55, 15 November 2014 (UTC)
	:::"Yes, yes, no" to my questions? I wasn't asking questions. Does that mean yes, yes, and no to the OP's questions? ] (]) 22:32, 15 November 2014 (UTC)

	::::No, the indent level indicates that I was responding to Mantis. ] (]) 00:23, 17 November 2014 (UTC)

	:See '']''.—] (]) 17:24, 14 November 2014 (UTC)
	::Be aware that ''Flatland'' is primarily a social satire rather than a scientific textbook, although I can second Wavelength's recommendation. ] (]) 19:50, 14 November 2014 (UTC)
	:::Yeah Flatland's coverage of 2D life is exceedingly patchy and inconsistent. I don't know why people still recommend it for that reason. A VASTLY better book about a 2D world is "]" - which is modern, has lots of clever insights and an actual, interesting plot. ] (]) 21:19, 14 November 2014 (UTC)
	:I wonder if you are actually talking about quantum states, as in the , for example an electron exist in several quantum states simultaneously, so is every particles in the universe, so we would be into an , and to my knowledge it's not possible to go from one "universe" to another, a bit like it's impossible to have a coin with a single face, both sides exist or none exist. ] (]) 21:03, 14 November 2014 (UTC)

	:In theories with small ] extra dimensions, ordinary matter spans the entirety of the extra dimensions—it's "fat" in the extra dimensions, if you like. Matter at much higher energies can be "thin" and have a position in the extra dimensions, but it will always be visible to ordinary matter because the ordinary matter is everywhere. In ] models, ordinary matter is stuck to a lower-dimensional surface (the brane), so it does have a position in the higher-dimensional space. However, I don't think there's any way for higher-dimensional objects not attached to a brane to exist in those models. There's nothing out there except gravity. The idea, common in fantasy/SF stories, that you could see a slice through a higher-dimensional object as it passed through our lower-dimensional world is not consistent with any physical theory I've heard of. -- ] (]) 23:02, 15 November 2014 (UTC)

	== Designing experiment to compare thermal clothing performance ==

	I was thinking of designing and performing an experiment at home to determine the performances of different items of thermal clothing and I was wondering if someone might care to contribute to ensure that I don't miss any opportunities and flaw my experiment.

	I thought I could simulate the body with a hot water bottle, placing a temperature sensor on the bottle and putting the thermal clothing over the bottle. Then the drop of the temperature could be logged over time. I would also measure the temperature of the air in the room and weigh the item of clothing excluding the sleeves. I would perhaps repeat the experiment with an additional, unvarying layer (e.g. a thick jumper) and with a fan blowing on the bottle/clothing from a fixed angle and distance. I could use a computer fan with known manufacturer specifications to give an indication of the amount of air being moved. I suppose I would also need an accurate hygrometer to know how cooling the moving air would be?

	Do I need other sensors? Should I redesign the experiment?

	I want to produce a table that will allow me to determine which clothing offers the best weight to insulation ratio and the best cost to insulation ratio. I guess I'll need to record the dimensions of the garments since some will be more generous than others.

	Are the thickness and permeativity to sweat worth consideration?] (]) 05:40, 14 November 2014 (UTC)

	:The thermal performance of some garments is likely to vary between them being worn, and simply draped over an object (e.g. thermal underwear is generally stretched when worn). ] (]) 09:27, 14 November 2014 (UTC)
	::...which can be good or bad, as it may restrict heat loss by air circulation. At least in Germany, some major outdoor stores have cold chambers with infrared cameras where they allow you to try out your particular piece of clothing on your particular body, and look at the heat loss. Some also simulate wind in the chamber periodically. However, this is more a marketing gimmick (with windows for your friends to look in and make fun of you), and probably not suitable for exact measurements or large-scale comparisons. --] (]) 10:56, 14 November 2014 (UTC)
	:One point that hasn't been mentioned yet - you need a ] for your experiment to have meaningful results. A hot-water bottle that's not wrapped in anything would be a possibility. Note also that the results will depend on the temperature (and humidity) of the room, which (presumably) isn't very precisely controlled, so you'll need to factor this in. A third point - weight is not the only important parameter when it comes to how comfortable clothing is, otherwise we'd all wear ] clothing in winter... ] (]) 19:05, 14 November 2014 (UTC)

	:There is an important difference between a hot water bottle and the human body. We generate heat internally - so the temperature of a human wouldn't vary much over the duration of the experiment, although we might have to resort to shivering and such to keep the body at the right temperature throughout. But the hot water bottle will gradually cool off. So perhaps we could imagine some kind of garment that releases heat very easily at body temperature, but insulates more and more effectively as the temperature drops (or vice-versa). That garment would perform much better in the experiment than it would with a human subject. Now, I can't think of a material that would act like that - but the whole thing about an experiment is to find that out and not be tricked by things like that. ] (]) 21:15, 14 November 2014 (UTC)

	::Then use an electric blanket. Changing out the three-position switch on most with a variable rheostat should allow you to generate a constant temperature. You wouldn't even need a blanket to get to 98.6; you'd merely need the ''surface'' of the blanket to be able to maintain ''skin temperature'', which for most people is somewhat less than body temperature. Use an electric blanket, calibrate it to output constant skin temperature, and wrap it in various fabrics. Measure the rate at which the outside of the fabric heats up, and you'll know which fabrics are better at retaining heat and which release it faster. --]''''']''''' 03:05, 15 November 2014 (UTC)

	*It seems to me that the technique will measure diffusive cooling pretty well but won't measure radiative cooling. I don't know how important that is on the whole -- it definitely comes into play in some situations. For example a person inside a tent at night will stay warmer than a person outside under a starless sky, even if the air temperature is the same and there is no wind, because the tent reflects radiation back. ] (]) 02:45, 15 November 2014 (UTC)

	*Something that hasn't been mentioned is how you will secure the fabric to the hot water bottle, and how the assembly will be held in the test chamber. I would suggest you sew the fabric samples into identical "water bottle cozy" shapes, such that you can slip the water bottle in and out, with a hook sewn in so you can suspend the assembly. This will help to ensure identical test conditions, which you won't get by just draping fabric over the hot water bottle. ] (]) 02:53, 15 November 2014 (UTC)

	As a home setup that is simple and economical, what about having a glass with a fixed amount boiling water surrounded with insulation except at the top which would have the garment, being careful not to touch the water, and then after a fixed amount of time, measure the temperature and the weight of the water, that will give you a relative measurement of the thermal insulation and how well the garment can "breath". You could also touch the garment to see if it feels wet. If you repeat the experiment with the same setup every times and compare the data for each garment you should get a good idea of the relative merit of each garment. Obviously a much better test would be to have someone wear the garment and do a standardized workout and ask for their impression, that would be a much more thorough and more meaningful evaluation. ] (]) 18:50, 15 November 2014 (UTC)

	== Shear strength of soil ==

	Does the size of aggregate in soil affect internal friction angle? My assumption is that finer aggregates are more likely to be rounded reducing it and also means there would be more weakness planes in between aggregates reducing cohesion. Am I correct?

	:I'm not sure what you mean by "aggregate" here, as this normally refers to a ] of specially graded material rather than soil. As stated in the ] article: "Soil particles can be classified by their chemical composition (mineralogy) as well as their size. The particle size distribution of a soil, its texture, determines many of the properties of that soil, but the mineralogy of those particles can strongly modify those properties. The mineralogy of the finest soil particles, clay, is especially important." In other words, the type of material at least as important than the grain size. And you certainly can't assume that finer grains are more likely to be rounded.--]\|] 16:39, 14 November 2014 (UTC)

	:Yes, size of aggregate will affect shear strength, but I agree with the above that smaller particles are not necessarily more rounded. The word "aggregate" is indeed used in ] (in the field of study, as well as our related articles). We have pretty good articles at ] and ] that discuss the effect of grain size and other features on soil properties. ] (]) 16:48, 14 November 2014 (UTC)

	== Why the DAF-2 gene is not extinct? ==

	Hi there,<br />
	I've read about ], and I wonder why that gene has been surviving?<br />
	] (]) 10:29, 14 November 2014 (UTC)
	:Because organisms who carry the gene don't die before they have a chance to pass it on to offspring. --]''''']''''' 10:40, 14 November 2014 (UTC)
	::Yes, and even if an ] does confer some disadvantage, it may remain in the population indefinitely if it also confers some benefit. In this case, DAF-2 seems to have a functional role in regulating reproductive development, and ] may indeed prevent the organism from being able to reproduce at all. Also, the ] takes part in controlling formation of ], which seems to confer a large benefit for the overall population. Some academic papers on the topic here . ] (]) 16:42, 14 November 2014 (UTC)
	:::Note also that even our article says "Disabling DAF-2 arrests development in the dauer stage which increases longevity, delays senescence and prevents reproductive maturity". ] (]) 19:27, 14 November 2014 (UTC)

	== Uniqueness of Human Bones? ==

	]
	If presented with a large box containing one set of adult male bones each from the 7 species of ] how many of the bones of the Human would be distinguishable from the others 1) by a layman, 2) by a Forensic Anthropologist without tools 3) by a Forensic Anthropologist with a full lab. I'm guessing #3 would be all, but for #1, I'm guessing a good number, but I'm not sure if #2 would be all (Free floating ribs and individual vertibrae for example, I guess would be tough. (Would adding any other animal beyond the great apes make things more complicated other than simply increasing the number of bones.] (]) 15:16, 14 November 2014 (UTC)

	:For #2, it's going to vary a great deal depending on the background of the individual. Primatology is often not part of the curriculum for, say, undergrad anthropology courses. It would be quite easy to get a doctorate in that field without any more than a passing knowledge of what chimp bones look like. The advantage they'd have over a layperson is their deep familiarity with human osteology. On the other hand, if their undergrad work or grad studies included courses in primatology and/or palaeoanthropology and/or comparative anatomy, then they'd be much better off. Even having a personal interest would greatly increase their ability. The answer for #1 would range from folks with almost literally no knowledge of what a skeleton looks like (I've seen an archaeology undergrad identify a squirrel pelvis as its skull) all the way to amateur bone hunters that could give the pros a run for the money. For #3, the biggest piece is probably not having a "full lab", but having a decent light and magnifying lens with a really good book. ] (]) 16:09, 14 November 2014 (UTC)

	::If the bones are fresh enough, DNA analysis should be able to cluster them into disjoint sets easily enough with a good lab. --] (]) 19:21, 14 November 2014 (UTC)

	:::Agreed. My point was simply that the expensive stuff is not necessary. Visual examination, especially with the aid of a diagnostic reference book, would be enough. ] (]) 15:31, 15 November 2014 (UTC)

	*The human foot, skull, and teeth are so different from the other apes, I would expect a high-school biology educated layman who could identify these would know right away whether he was dealing with an ape or a human. Likewise, the limb proportions, relative length of the thumb, pelvis breadth, spine curvature, location of the ], ribcage shape, and bowing of the legs are quite distinct. Many of these things are diagnostic of human, non-human on their own, and even if you only had a hand, if you knew how to articulate it it would be quite obvious from the ]. See this website on , , and our articles, ] and ]. ] (]) 23:20, 14 November 2014 (UTC)

	*As for #1, the skull alone should tell the average layman whether it's a human or some other extant primate. However, if you included some extinct primates, like Neanderthals, that would make it tougher. The remaining bones would be harder to identify, in isolation. Only by laying out the bones in the right order to reconstruct the individual would you get a sense for the proportions of the bones, and hence the species. A further complication would be if the set of bones was atypical for that species. For example, the ]'s skull might be difficult to identify as human. ] (]) 15:48, 15 November 2014 (UTC)
	::Neanderthals were human, they interbred with us. The premise is a full set of adult male bones, so the skull alone is the end of the story. Even comparing the femur and the pelvis is enough to draw an instant conclusion. Once you've found a heel the quiz is over. ] (]) 19:43, 15 November 2014 (UTC)
	:::The original question was how many of the individual bones could be identified as human - clearly, identifying a set if you know they all belong together is easier. Dealing with adult specimens makes it simpler though - if you don't know the age, the size may not help much, and the differences between species tend to become more apparent with age. ] (]) 19:56, 15 November 2014 (UTC)
	::::Yes, but we are still presented with a full set of bones from two individuals, not just one carpal bone, which are the only bones I can see as problematic for a layman with a book, although they are bigger in gorilla hands than the are in ours.
	::::If the sets could be sorted (a layman with a book should be able to do this) none of the bones would be mistaken. A forensic anthropologist would not need a lab, as he'd rearticulate the human first, from head down and sine out, then the gorilla, then check for mistakes. The entire anatomy of a human is modified by two things. The ]s are designed to allow the tip of the thumb to touch the tips of all four fingers, not for ] or ]
	::::The rest of the skeleton, the feet, legs, pelvis, spinal curvature, and base of the skull are all designed for a permanent upright stance. our legs are long, straight, gracile and knock-kneed compared to apes. Our pelvis is small compared to our femur, but our head is large compared to our pelvis. The hole where our spinal chord enters the skull is on the bottom, in apes further towards the back.
	::::As intelligent social animals, we don't have fangs for canines, but we do have chins and foreheads, effectively expanding our faces and brain capacity in comparison to apes. The list is endless. ] (]) 05:02, 16 November 2014 (UTC)
	:::::"Designed"? ] (]) 05:06, 16 November 2014 (UTC)
	::::::You obviously know exactly what was meant, or you wouldn't have asked the question. So I'll just assume you are particularly grumpy today, and ignore it. ] (]) 20:41, 16 November 2014 (UTC)
	::::::Design is ], anyway. ] ] 08:04, ], ] (UTC)
	::::::"Designed" as in "designed by Mother Nature," i.e. by evolution. Not actively designing like an architect, but passive design by natural selection. ←] <sup>'']''</sup> ]→ 13:37, 17 November 2014 (UTC)
	:::The idea that there's a binary determination between same-species/not-same-species, and that the determination is "can interbreed" is simplistic. Even among extant species that's kind of the "high school" understanding of the subject, and when comparing long extinct species with modern ones the question is even more complicated.
	:::Beyond that, we don't even know if Homo Sapien/Neanderthal breeding normally produced fertile offspring, or just on very rare occasions. (Just like Lion/Tiger breeding will usually create infertile offspring, but on rare occasions the offspring is fertile. Does that automatically make them the "same species"? Clearly not.)
	:::In fact, while the theory that our Cro-Magnon ancestors interbred with Neanderthals has gained a lot of support, it is far from proven, and even among supporters of the theory, many of them believe that it only 'worked' with Cro-Magnon mothers, and didn't work the other way around. Does that make them the same species? Or different species? Neither. "Species" is an arbitrary distinction. Anyone suggesting otherwise for the purposes of nit-picking is more wrong than the person they're nit-picking! ] (]) 07:29, 17 November 2014 (UTC)
	::::You contradict yourself. You say a binary distinction is arbitrary, and then you ask us to draw distinctions. You know very well that interbreeding did take place and did produce fertile offspring, and your nitpicking here is way off topic. I said "Neanderthals were human, they interbred with us." Stu could have asked for a clarification, but he did'nt. Presumably you also know ...Nevermind, I am not going to take you seriously. Stu can read ] if he's interested. ] (]) 18:35, 17 November 2014 (UTC)
	:::::Sure, there is a gray area. But given ]s and ]s and ] (nicotine-overdose danger tomatoes(!), "can interbreed (ever)" seems too generous for a useful concept. "(50%/number of matings in a male's life (unpremature death, to satiety)) of inter-group matings with nubile females at random point in menstrual cycle produce 1 fertile offspring" through "has half the rate of fertile offspring as intra-group matings" seems like a more useful gray zone. ] (]) 20:24, 17 November 2014 (UTC)
	::::::Unless your point is that Neanderthals were apes, you're arguing OR about a dead population, so we can't run any experiments, SMW. But we can say that there's more Neanderthal blood out there now than there ever was when they were a distinct population, since at a low estimated end of 2% of the extra-African genome, that's the equivalent of 100,000,000 descendants, easily. See of ''Homo sapiens neanderthalensis'', and ''Homo sapiens sapiens''. ] (]) 20:39, 17 November 2014 (UTC)

	== Dowel action ==

	What is dowel action on a concrete bean in very simple terms? {{unsigned\|194.66.246.59}}

			= December 15 =
	:It is a "beam", not a "bean". Dowel action is the shear resisted by the reinforcement of the concrete.

			== help to identify ] ==
	:We have articles on ] and ] and ] and ]. Here are a few slides that explain dowel action with illustrations Also, please sign your posts with four ]s, like this <nowiki>~~~~</nowiki> ] (]) 22:03, 14 November 2014 (UTC)

			] in New South Wales Australia]] Did I get species right? Thanks. ] (], ]) 06:56, 15 December 2024 (UTC)

			:related: https://species.wikimedia.org/Wikispecies:Village_Pump#help_to_identify_species ] (], ]) 06:57, 15 December 2024 (UTC)
	= November 15 =

			:FWIW, I can't detect any visible differences between the plant in this photo and the ones illustrated in the ] and the ] articles. However, the latter makes it clear that ''Polygala'' is a large genus, and is cultivated, with hybrids, so it's possible that this one could be a close relative that differs in ways not visible here, such as in the bark or roots. That may or may not matter for your purposes. {The poster formerly known as 87.81.230.195} ] (]) 10:11, 15 December 2024 (UTC)
	== Questions about Coenzyme A ==

			== How to address changes to taxonomy ==
	# Why is it seemingly so rare as a dietary supplement?
	# Do you find any theoretical reason in the claim CoA supplementation increase Lipolysis in some rare cases of "low" lipolysis in compare to "high" Glycolysis (Please, take your time to handle this question and try not to be too much skeptic or general in your answer), Thanks to all the helpers. ] (]) 09:32, 15 November 2014 (UTC)

			Hi all,
	:Humans, like all animals, can synthesize their own ]. As a result, it is very rare to be considered deficient in CoA except in cases of severe malnutrition. In addition, CoA does not handle digestion well, so most of the CoA that you eat (or attempt to consume as supplements) will usually be broken down into smaller molecules before entering the blood. Given that, most of the time people choose to supplement with precursor molecules, such as ] (]) or ], which the body knows how to turn into CoA rather than supplement with CoA directly. ] (]) 18:38, 15 November 2014 (UTC)
			I am a biology student brand new to wiki editing who is interested in cleaning up small articles/stubs for less known taxa. One that I've encountered is a mushroom that occurs in the pacific northwest ('']''). The article mentions that this fungus is occasionally mistaken for another fungus, '']''. <br>

			However, the issue I've run into is that ''F. pinicola'' used to be considered a single species found around the world, but relatively recently was split into a few different species. The original name was given to the one that occurs in Europe, and the one in the pacific northwest (and thus could be mistaken for ''F. ochracea'') was given the name '']''.
			<br>
			The wiki page says <blockquote><p>Historically, this fungus has been misidentified as ''F. pinicola.'' When both species are immature, they can look very similar, but can be distinguished by lighting a match next to the surface of the fungus. ''F. pinicola'' will boil and melt in heat, while F. ochracea will not.</p></blockquote>
			<br>Since the source says ''pinicola'' (as likely do most/all other sources of this info given the change was so recent), and since technically it's true that they used to be mistaken for it... what would be the most appropriate way to modernize that section?
			<br>

			<B>My questions are</b>:
	= November 16 =
			Should I replace ''F. pinicola'' with ''F. mounceae''? Or is that wrong because the source doesn't refer to it by that name? Would it be better to write something like (now known as/considered ''F. mounceae'') next to the first mention of the species? Or is that a poor choice because it implies all the members of ''F. pinicola'' were renamed ''F. mounceae''?
			<br>

			Any advice on how to go about updating this section is incredibly appreciated
	== Width of gas lines. ==
			<br>
			] (]) 10:21, 15 December 2024 (UTC)
			:::First, take these sorts of questions to the relevant Wikiproject, in this case ]. I am not as familiar with the consensus at ], but it seems like they defer to '']'' and ] to decide. Those sources presently seem to consider '']'' a good species. Also, be careful about "replacing", there are rules to ensure the continuity of the article history. By the way, there is a hilarious but unencyclopedic/copyvio recipe appended to the '']'' article. <span style="font-family: Cambria;"> ] (])</span> 11:09, 15 December 2024 (UTC)
			::::Thanks for the tips, I didn't know about projects so I'll go read up on that. And thanks for the warnings about replacing things. I've been reading a lot of help pages, but I'm still in the process of learning the all conventions and what mechanics break if you do things the wrong way.
			::::I actually saw the recipe ages ago before I made my account and completely forgot about it... it was one of many things that prompted me to get into wiki editing. ] (]) 23:12, 15 December 2024 (UTC)

			== Does stopping masturbation lead to sperm DNA damage? ==
	I was running some gas lines for a unit heater i bought and the manual said i needed larger diameter pipe run depending on the distance the pipe was traveling.

			I'm looking for information on the potential link between the frequency of ejaculation (specifically through masturbation) and sperm DNA damage. I've come across some conflicting information and would appreciate it if someone could point me towards reliable scientific studies or reviews that address this topic.
	I assume this is to keep a steady pressure, but the pipes throttle at the beginning and the end to a much smaller diameter, so i would think that the throttling would bottleneck the system no matter if i increased the pipe diameter AFTER the throttle.

			Specifically, I'm interested in whether prolonged periods of abstinence from ejaculation might have any negative effects on sperm DNA integrity. Any insights or links to relevant research would be greatly appreciated. ] (]) 17:08, 15 December 2024 (UTC)
	but apparently it doesn't matter. Why exactly do i need larger diameter piping if i'm going a larger distance? how does an increase of diameter allow for an increase of flow rate? and why does it not matter if there is a reducer on either ends of the pipe?
			:Only males may abstain from sperm-releasing ] that serves to flush the genital tract of old sperm that in any case will eventually dissipate. No causal relationship between masturbation and any form of mental or physical disorder has been found but abstinence may be thought or taught]]] to increase the chance of wanted conception during subsequent intercourse. ] (]) 00:51, 16 December 2024 (UTC)
			::There's many rumors about that topic. One is that not ejaculating frequently increases the risk of developing ]. <span style="font-family: Cambria;"> ] (])</span> 01:02, 16 December 2024 (UTC)
			:Nothing really conclusive but there's some evidence that short periods are associated with lower DNA fragmentation, see<small>
			:* {{Cite journal \|last=Du \|first=Chengchao \|last2=Li \|first2=Yi \|last3=Yin \|first3=Chongyang \|last4=Luo \|first4=Xuefeng \|last5=Pan \|first5=Xiangcheng \|date=10 January 2024 \|title=Association of abstinence time with semen quality and fertility outcomes: a systematic review and dose–response meta‐analysis \|url=https://onlinelibrary.wiley.com/doi/10.1111/andr.13583 \|journal=Andrology \|language=en \|volume=12 \|issue=6 \|pages=1224–1235 \|doi=10.1111/andr.13583 \|issn=2047-2919}}
			:* {{Cite journal \|last=Hanson \|first=Brent M. \|last2=Aston \|first2=Kenneth I. \|last3=Jenkins \|first3=Tim G. \|last4=Carrell \|first4=Douglas T. \|last5=Hotaling \|first5=James M. \|date=16 November 2017 \|title=The impact of ejaculatory abstinence on semen analysis parameters: a systematic review \|url=https://pmc.ncbi.nlm.nih.gov/articles/PMC5845044/ \|journal=Journal of Assisted Reproduction and Genetics \|language=en \|volume=35 \|issue=2 \|pages=213 \|doi=10.1007/s10815-017-1086-0 \|issn=2047-2919 \|pmc=5845044 \|pmid=29143943}}
			:* {{Cite journal \|last=Ayad \|first=Bashir M. \|last2=Horst \|first2=Gerhard Van der \|last3=Plessis \|first3=Stefan S. Du \|last4=Carrell \|first4=Douglas T. \|last5=Hotaling \|first5=James M. \|date=14 October 2017 \|title=Revisiting The Relationship between The Ejaculatory Abstinence Period and Semen Characteristics \|url=https://pmc.ncbi.nlm.nih.gov/articles/PMC5641453/ \|journal=International Journal of Fertility & Sterility \|language=en \|volume=11 \|issue=4 \|pages=238 \|doi=10.22074/ijfs.2018.5192 \|issn=2047-2919 \|pmc=5641453 \|pmid=29043697}}
			:</small>
			:for example. ] (] • ]) 02:12, 16 December 2024 (UTC)
			:Mature sperm cells do not have ] capability.<sup></sup> Inevitably, as sperm cells get older, they will naturally and unavoidably be subject to more and more ]. Obviously, freshly produced spermatozoa will, on average, have less DNA damage. It is reasonable to assume that the expected amount of damage is proportional to the age of the cells, which is consistent with what studies appear to find. Also, obviously, the more the damage is to a spermatozoon fertilizing an oocyte, the larger the likelihood that the ] in the resulting zygote, which does have DNA repair capability, will be incomplete. The studies I've looked at did not allow me to assess how much this is of practical significance.  --] 09:40, 16 December 2024 (UTC)

			= December 16 =

			== ] ==
	] (]) 02:37, 16 November 2014 (UTC)

			Thanks to those who answered my ], I think it should be added to a disambiguation page. If anyone wants to help me write that, reach out.
	:Same thing happens with electricity. Longer extension cords need to be heavier gauge wire for the same load. Pipes exhibit resistance to flow based on their diameter AND length. For short runs the differences can be miniscule, but natural gas pressure in household lines is measured in ounces, so even tiny differences can affect the flow rate. ] (]) 04:11, 16 November 2014 (UTC)

			A sandpile seems disorganized and inert, but these are critically self-organizing. Do the frequency and size of disturbances on sand dunes and snowy peaks follow power law distribution?
	== Rosetta Orbital Period ==
			] (]) 01:18, 16 December 2024 (UTC)
			:Shouldn't this be at the Math Desk? <span style="font-family: Cambria;"> ] (])</span> 05:12, 16 December 2024 (UTC)
			::If the question is not about the model mentioned in the heading but about the physical properties of sand dunes and snowy peaks, this here is the right section of the Reference desk.  --] 08:51, 16 December 2024 (UTC)
			:::I await a non-mathematical answer. <span style="font-family: Cambria;"> ] (])</span> 09:23, 16 December 2024 (UTC)
			::::It depends is probably a fairly reasonable non-mathematical answer for these kinds of systems. For sand dunes anyway, sometimes avalanche frequency is irregular and the size distribution follows a power law, and sometimes it's close to periodic and the avalanches span the whole system. It seems there are multiple regimes, and these kinds of systems switch between them. ] (]) 09:35, 16 December 2024 (UTC)
			:::::Thank you! I'm impressed this seems so casual, but surely you read this somewhere that might have a URL?
			:::::] (]) 22:29, 19 December 2024 (UTC)

			:Hi, this is an interesting and somewhat open question! A lot of work is done on these models but much less on careful analyses of real dunes. I did find that is freely accessible and describes some physical experiments and how well they fit various models. The general answer seems to be that the power law models are highly idealized, and determining the degree to which any real system's behavior is predicted by the model ahead of time is very difficult. Update: and it does include discussion of how well the model fits experiments.] (]) 17:21, 16 December 2024 (UTC)
	Since the comet has such low gravity, will Rosetta be able to maintain a conventional orbit around the comet? If so, how long will that orbital period be? I am guesstimating about a day (24 hours). Altitude 3 miles, orbital path 20+ miles, escape velocity 1 MPH. ] (]) 04:05, 16 November 2014 (UTC)
			::That dissertation is great!
			::] (]) 22:30, 19 December 2024 (UTC)

			== Polar night ==
	: I believe that Rosetta isn't in a 'free' orbit. It does several powered 'turns' in each orbit (I think, every 60 degrees). So, in effect, it's flying a bunch of nearly straight lines at much higher than escape velocity. I read someplace that Rosetta's speed relative to the comet is about 25 meters/second (sorry, I don't remember where I saw that). According to our article, the orbital distance is 29km (roughly) - although at times, they've reduced that to as little as 10km and started out at 100km. If the orbit was circular, then the circumference of that orbit is 2 pi x 29000 meters, which is around 200,000 meters. At 25 m/sec we get an orbital period of around 7000 seconds...around 2 hours. For a more exact answer, we'd need more details about the shape of the orbit and the fuel burns to keep it like that. When it was out further from the comet, I believe the 'natural' orbit was 26 days.
	: An orbit that long would be useless while interacting with the lander because there would be periods of many days when they'd be unable to communicate. Hence the powered turns. ] (]) 15:45, 16 November 2014 (UTC)

			Are there any common or scientific names for types of polar night? The types that I use are:
	== Signals from UFOs ==
			* ''polar night'' - meaning a day when sun's altitude remains below horizon entire day (there is no daylight at solar noon, only civil twilight), occurring poleward from 67°24′ north or south
			* ''civil polar night'' - meaning a day when sun's altitude remains below -6° entire day (there is no civil twilight at solar noon, only nautical twilight), occurring poleward from 72°34′ north or south
			* ''nautical polar night'' - meaning a day when sun's altitude remains below -12° entire day (there is no nautical twilight at solar noon, only astronomical twilight), occurring poleward from 78°34′ north or south
			* ''astronomical polar night'' - meaning a day when sun's altitude remains below -18° entire day (there is no astronomical twilight at solar noon, only night), occurring poleward from 84°34′ north or south

			These names were changed on ] article, and I wnat to know whether these named I listed are in use in any scientific papers, or in common language. (And I posted that question here and not in language desk because I think that this is not related to language very tightly.)
	If there as many ]s out there as people would have us believe, why dont we pick up some electromagnetic signals from them via, for instance, the ] program? Also, if UFOs exist, what do they want?--] (]) 13:13, 16 November 2014 (UTC)
			--] (]) 18:56, 16 December 2024 (UTC)

			:Some definitions at from the ]. ] (]) 22:55, 16 December 2024 (UTC)
	:We don't hear little green men talking on their walkie-talkies because they are not here. There is almost certainly life out there somewhere (it being a big galaxy and an even bigger universe), but there is no reliable evidence that we are being visited. Alien UFOs, the Bermuda Triangle, the Loch Ness Monster, and ghosts are all more ] than they are scientific ones. Do you want to believe? -- ] 14:29, 16 November 2014 (UTC)
			::These seem to be generalizable as: X polar night is a period, lasting not less than 24 hours, during which the sun remains below the horizon and there is no X twilight. The specific definitions depend then on the specific definitions of ]/]/]. These can be defined with a subjective observational standard or with an (originally experimentally determined) objective standard.  --] 10:36, 17 December 2024 (UTC)
	:::There are a few scientists who have theorized that there may not be any complex life anywhere else in the ], based on extremely low values in the ]. I am aware of one that said that the merger of the ] with the ] was an extremely unlikely event. Other, more commonly theorized values for the factors in the Drake equation compute the likelihood that there is life elsewhere in the Milky Way, but not within communicating distance. Remember that the Milky Way is an '''astronomically''' large place. If relativity is correct and the speed of light is invariant, then there are limits to how far intelligent beings, even long-lived ones, would travel. Even if superluminal travel is possible, the Milky Way is still an '''astronomically''' large place. ] (]) 21:25, 17 November 2014 (UTC)
			:::FWIW, I as a former amateur astronomer have never previously thought about the question of ''Polar'' twilight and night nomenclatures, but immediately and completely understood what the (previously unencountered) terms used in the query must mean without having to read the attached descriptions. {The poster formerly known as 87.81.230.195} ] (]) 16:34, 17 December 2024 (UTC)
	:::As to whether UFOs are a cultural phenomenon, ] has theorized that there is something about humans, maybe even in brain wiring, so that humans want there to be other beings with whom we can communicate. In the past, this desire resulted in various sorts of folkloric humanoids such as, in European culture, dwarves, trolls, and elves, having other names in other cultures. In modern times, they are extraterrestrials. So maybe they are both a cultural phenomenon and a psychological phenomenon. ] (]) 21:30, 17 November 2014 (UTC)
	:If by "UOFs" you were not referring to aliens sighted visiting Earth but instead you were speaking metaphorically of extraterrestrial intelligence in general, and your question was why ] has not been successful to date, then you should make that clear. -- ] 14:42, 16 November 2014 (UTC)
	]
	::Upper atmosphere objects. Do YOU believe these? ]--] (]) 14:47, 16 November 2014 (UTC)

			= December 17 =
	:::There is a large community of people out there who take NASA imagery and "enhance" it. Sadly, because they are unschooled in how to do image enhancement correctly, they make stupid mistakes and generate 'artifacts' that look just like UFOs or alien cities or whatever their fevered imaginations can come up with. My favorite way to demonstrate that is this from a post I did here back in 2009 were I take the period at the end of the original question and 'enhance' it until there is a really clear picture of an alien city, complete with buildings, streets and shadows that are convincingly cast by those buildings! I use it so much, I made a copy on my own website:

			== differential equations with complex coefficients ==
	:::* http://sjbaker.org/index.php?title=Alien_City_hidden_in_Wikipedia_post

			In an intro ODE class one basically studies the equation <math>\dot x=Ax</math> where x is a real vector and A is a real matrix. A typically has complex eigenvalues, giving a periodic or oscillating solution to the equation. That is very important in physics, which has various sorts of harmonic oscillators everywhere. If A and x are complex instead of real, mathematically the ODE theory works out about the same way. I don't know what happens with PDE's since I haven't really studied them.
	::: I've seen photos of UFO's that were the result of this exact same thing. A tiny white speck in an image (could be dust on a lens, or a star or something) get "enhanced" until you get a nice blurry image that looks just like a classic UFO.
	::: ] (]) 15:17, 16 November 2014 (UTC)

			My question is whether the complex case is important in physics the way the real case is. Can one arrive at it through straightforward coordinate transformations? Do the complex eigenvalues "output" from one equation find their way into the "input" of some other equation? Does the distance metric matter? I.e. in math and old-fashioned physics we use the Euclidean metric, but in realtivity one uses the Minkowski metric, so I'm wondering if that leads to complex numbers. This is all motivated partly by wondering where all the complex numbers in quantum mechanics come from. Thanks. ] (]) 22:54, 17 December 2024 (UTC)
	::Aliens are bound by the same laws of physics that we are. Getting from wherever they live to us would take hundreds to thousands of years - and they'd have been unlikely to detect our civilization hundreds or thousands of years ago. It's unlikely that they'd even be able to detect that we're here. With our present technology, we'd be unable to detect a human-scale civilization orbiting a star more than a couple of lightyears away. So:
	::* "''If there as many ]s out there as people would have us believe''"...well that number would be zero...assuming you're listening to people who have seriously thought about it!
	::* "''if UFOs exist, what do they want?''"...they don't exist, so the question is moot.
	::If you really want an answer to the hypothetical question of what it would be like if they '''''DID''''' exist, then I suppose the chain of reasoning is something like:

			:Perhaps I don't understand what you are getting at but simple harmonic motion is xdot=jwx where w is angular frequency and j is i ] (]) 00:35, 18 December 2024 (UTC)
	::# If they could get here at all, they'd have to have some pretty amazing technology.
			:If PDEs count, the ] and the ] are examples of differential equations in the complex domain. A linear differential equation of the form <math>\dot x=Ax</math> on the complex vector space <math>\mathbb{C}^n</math> can be turned into one on the real vector space <math>\mathbb{R}^{2n}</math>. For a very simple example, using <math>n=1,</math> the equation <math>\begin{bmatrix}\dot z\end{bmatrix} = \begin{bmatrix}i\end{bmatrix}\begin{bmatrix}z\end{bmatrix}</math> can be replaced by
	::# If they wanted to destroy us, and they are that advanced, they could easily do before we ever knew they were there. If they were prepared to spend hundreds of years patiently getting here, they could spend 50 more years to gently deflect a dinosaur-extinction-event sized asteroid to wipe us all out...and we'd never even know they'd done it until we were all dead. So, clearly that's not what they want.
			::<math>\begin{bmatrix}\dot x\\\dot y\end{bmatrix} = \begin{bmatrix}0&-1\\1&0\end{bmatrix}\begin{bmatrix}x\\y\end{bmatrix}.</math>
	::# If they wanted us to detect them, they could ''very'' easily make themselves known by any number of impressive and undeniable ways - and they clearly haven't done that either.
			: --] 01:11, 18 December 2024 (UTC)
	::# So they must want to remain hidden and so they certainly wouldn't go around broadcasting radio signals that they know we can detect.
			:::Shouldn't this be at the Math Desk? It almost seems like the IP could be trolling, given the same question just above. <span style="font-family: Cambria;"> ] (])</span> 14:49, 18 December 2024 (UTC)
	::# Ergo, if they exist at all, we're unlikely to be able to detect them.
			::::The question whether the complex case is important <u>in physics</u> the way the real case is, is not a maths issue. IMO the Science section is the best choice. I do not see another post that asks the same or even a related question.  --] 21:51, 18 December 2024 (UTC)
			:::::Just as above, I await a non-mathematical answer to this question. <span style="font-family: Cambria;"> ] (])</span> 07:01, 19 December 2024 (UTC)

			Thanks all. Greglocock, your SHO example is 1-dimensional but of course you can have a periodic oscillator (such as a planetary orbit) in any orientation in space, you can have damped or forced harmonic oscillators, etc. Those are all described by the same matrix equation. The periodic case means that the matrix eigenvalues are purely imaginary. The damped and forced cases are where there is a real part that is negative or positive respectively. Abductive, of course plenty of science questions (say about how to calculate an electron's trajectory using Maxwell's equations) will have mathematical answers, and the science desk is clearly still the right place for them, as they are things you would study in science class rather than math class. Lambiam, thanks, yes, PDE's are fine, and of course quantum mechanics uses complex PDE's. What I was hoping to see was a situation where you start out with real-valued DEs in some complicated system, and then through some coupling or something, you end up with complex-valued DEs due to real matrices having complex eigenvalues. Also I think the Minkowski metric can be treated like the Euclidean one where the time coordinate is imaginary. But I don't know how this really works, and Misplaced Pages's articles about such topics always make me first want to go learn more math (Lie algebras in this case). Maybe someday. ] (]) 07:25, 19 December 2024 (UTC)
	:: If there were UFO's in orbit around the earth, they might communicate with each other using lasers or some other sort of directed signal that avoided splattering light or radio in all directions. They'd undoubtedly use stealth technology that would prevent us from picking them up with radar or other such tricks.
	:: SETI goes to a lot of trouble to eliminate signals that are too close to earth to be a signal from another star system - so even if they could pick up UFO's, they'd be actively ignoring them...but there are lots of other people out there who track space debris and look for unusual satellite activity from potential (human) enemies who could detect an easily-detected alien ship.

			= December 18 =
	:: What do they (hypothetically) want? Who knows? We can't detect them.

			== Why don't all mast radiators have top hats? ==
	:: A species that's capable of all of this wouldn't be dumb enough to show themselves to people by abducting them, doing experiments on them and letting them go afterwards...if they were trying to keep themselves hidden, they're doing a really terrible job of doing that.

			]Our ] article describes a device called a "top hat" which increases the range for mast radiators that can't be built tall enough.
	:: All of these sad people with nothing better to do in their lives than make up stories are feeding you bullshit...and until a UFO lands on the Whitehouse lawn...we can probably ignore these reports. People are endlessly capable of deluding themselves and going out and making up a pack of lies to make themselves feel more important...it's a part of human nature.

	:: ] (]) 15:02, 16 ~~November~~ ~~2014~~ (UTC)		So, why would you bother building a mast radiator without a top hat? Couldn't you just build it shorter with the top hat, and save steel? ] (]) 15:00, 18 December 2024 (UTC)
	::::And Steve has only shown one of many types of image distortion ''only caused by a specific conversion artifact of the ] image compression algorithm.'' There are many, many other image artifacts that can be caused by camera optics, digital sensors, and all kinds of other complicated software processing, all of which are omnipresent on today's digital cameras! If one is looking for noise, noise is easy to find! ] (]) 16:12, 16 November 2014 (UTC)
	:::::Yes, exactly. In my example, in addition to the JPEG compression artifacts, I also had our hypothetical UFO investigator use an "Edge enhance" function - which is great at highlighting edges at normal pixel sizes - but when you enlarge the image, you get dark and light fringes along all the edges - which make just dandy fake shadows. I've seen dozens of supposed alien vehicles and buildings that had inadvertently been created from nothing more than edge enhancement and subsequent magnification. ] (]) 23:32, 16 November 2014 (UTC)

			:The main source cited in our article states, "{{tq\|Top loading is less desirable than increased tower height but is useful where towers must be electrically short due to either extremely low carrier frequencies or to aeronautical limitations. Top loading increases the base resistance and lowers the capacitive base reactance, thus reducing the ''Q'' and improving the bandwidth of towers less than 90° high.}}"<sup></sup> If "reducing the {{serif\|''Q''}}" is an undesirable effect, this is a trade-off design issue in which height seems to be favoured if circumstances permit.  --] 21:41, 18 December 2024 (UTC)
	:As far as why an alien species might come to Earth and yet remain hidden, the obvious answer is for scientific study of Earth life, while following a version of the ]. Earth scientists would absolutely love to find any extraterrestrial life to study, even if it was only as complex as a virus or bacterium. ] (]) 15:16, 16 November 2014 (UTC)

			== Name of our solar system ==
	::This is a common idea - but if there is an 'noninterference directive', why are they (supposedly) kidnapping dozens to hundreds of humans, doing nasty experiments on them and then releasing them again? If a species that was that advanced wanted to investigate us without being noticed...I really don't think we'd notice them. ] (]) 23:32, 16 November 2014 (UTC)

	A few scientists have actually addressed this question, but their scientific inquiries are usually drowned out by the sea of nonsense, fiction, and pseudoscience. As a start, you might look for at your local library. It was written by ] and adapted into English by ]. The book provides insightful perspectives on intelligent extraterrestrial life from some very intelligent terrestrials. ] (]) 16:21, 16 November 2014 (UTC)

			Is our star system officially called "Sol", or is that just something that came from science fiction and then became ubiquitous? ] (]) 22:06, 18 December 2024 (UTC)
	:*What has not been pointed out is why there are so many UFO's up there. A UFO is simply any aerial object or phenomena that the observer can not recognise as (say) a Boeing 747, hot air balloon, atmospheric sounder, classified military drone etc. Hence the official term ''unidentified flying object'' or UFO for short. Just because a DEFCON alert is issued, does not mean that these (possible) alien objects are of extra terrestrial origin. They might be Russian reconnaissance aircraft or a publicity inflatable that has escaped it tether. Most civilian observers of UFO's don't have radar or any other apparatus with which to objectively record what they witness. If they did, they my well receive electromagnetic signals. Also, people are easy fooled. I saw a youtube video shot at night of which was claimed as an 'obviously' extra terrestrial craft because it was doing maneuvers that no known terrestrial craft could do – except I have seen ] craft maneuvering the exactly same way. Airships can remain stationary, tilt their noses up and down and suddenly change their apparent shape by turning nose or tail toward the observer. They (Airship Industries) demonstrated their craft to the US defense industry as a possible radar platform – in the very same desert -where the video was shot. It obviously had its internal gas bag lights on – hence it appearance in the sky. This was maybe in order that ground observers could see the maneuvers. These internal lights are there, so that they can serve both day and night as advertising bill boards. But to the audience at this UFO convention, it was by definition a true UFO as no-one identified it for them. If the object escapes the observers experience, it is by definition a UFO and thus there are a lot of them about (both UFO's and observers).--] (]) 18:24, 16 November 2014 (UTC)
			:It's called the ], and its star is called Sol, from Latin via French. Hence terms like "solstice", which means "sun stands still" in its apparent annual "sine wave" shaped path through the sky. ←] <sup>'']''</sup> ]→ 23:31, 18 December 2024 (UTC)
	::Indeed. As my father-in-law (ex-RAF) used to say, "Any FO is a UFO until it is I". (Any Flying Object is an Unidentified Flying Object until it is Identified) --] (]) 20:39, 16 November 2014 (UTC)
			:::Via French? According to the OED, it came direct from Latin.<sup></sup>  --] 11:45, 19 December 2024 (UTC)}}
	:::<small> That reminds me of the RAF ] system. It worked well at night too, so everybody was told that fighter pilots ate carrots to help them see in the darks, to hide the real reason from the Luftwaffe high command (namely the gravitationally challenged Hermann Göring) for so many successful RAF night-time intercepts. To be pedantic, should mention also, that they donned red goggles whilst on the ground to preserve their night vision and they were very well trained.</small> --] (]) 21:37, 16 November 2014 (UTC)</small>
	::::~~There~~ is ~~somewhat~~ ~~of a disconnect between the strict dictionary definition of UFO vs~~. ~~the way it's used in popular culture~~. These supposed extraterrestrial vehicles were initially being described as "flying saucers". Donald Keyhoe's organization NICAP called them "aerial phenomena". The term UFO was eventually latched onto, and over time its pop culture meaning usurped its natural meaning. ←] <sup>'']''</sup> ]→ 13:55, 17 ~~November~~ ~~2014~~ (UTC)		::::Old French plus Latin. ←] <sup>'']''</sup> ]→ 14:25, 19 December 2024 (UTC)
			:::::Also in Old French, the word meaning "sun" was '']''.  --] 23:42, 19 December 2024 (UTC)
	:::: I really doubt that there are many people left in the world who use "UFO" to mean anything other than alien spacecraft...just like nobody uses "gay" to mean "happy" or "computer" to mean a person who does arithmetic for a living. The word has changed meanings and we're all just waiting for the dictionaries to catch up and mark the old meaning "(archaic)". I'd bet that when someone officially reports an unknown object in the sky these days, the official parties involved steer well clear of calling it a "UFO"...just because every time they do it and the nut-jobs get to hear about it, it's a whole major nonsense-fest. So there are almost certainly new terms used to replace the original sense of "UFO" - maybe "non-specific aerial contact" or something. However, this doesn't prevent people from telling us that the term has some dusty old archaic meaning. Well, I got news for you - it doesn't. Here in 2014, "UFO" means "Aliens spaceship" and any other interpretation is mere pedantry. ] (]) 21:28, 17 November 2014 (UTC)
			::Let's say {{fact}} to that claim. The star is indeed called Sol if you're speaking Latin, but in English it's the Sun (or sun). Of course words like "solar" and "solstice" derive from the Latin name, but using "Sol" to mean "the Sun" does seem to be something from science fiction. --] (]) 06:04, 19 December 2024 (UTC)
			:::"Sol" is occasionally used to mean the Sun by astronomers. I feel like it is used in contexts where it is necessary to distinguish our experience with the Sun here on Earth, such as sunsets, from more "sterile" aspects of the Sun one might experience off the Earth. <span style="font-family: Cambria;"> ] (])</span> 08:56, 19 December 2024 (UTC)
			::::Being an astronomer myself, I don't think I've ever heard anyone use "Sol" outside of a science fiction context. --] (]) 09:06, 19 December 2024 (UTC)
			::::::Scientific articles that use the term Sol; and . These are rather speculative but as I mentioned, the usage is for off-planet situations. <span style="font-family: Cambria;"> ] (])</span> 13:05, 19 December 2024 (UTC)
			:::::Using Sol, Terra and Luna to refer to the Sun, Earth and Moon only happens if you write your entire article in Latin and in science fiction, not in regular science articles. They are capitalised though. Just as people write about a galaxy (one of many) or the Galaxy (the Milky Way Galaxy, that's our galaxy). The Solar System is also capitalised. ] (]) 10:38, 19 December 2024 (UTC)
			::::::The article says "Sol" is the "personification" of the sun. Google Image the term "old Sol" and you'll see plenty of images of the sun with a face, not just Sci-Fi stuff. And "Luna" is obviously the basis for a number of words not connected with Sci-Fi. Lunar orbit, lunar module, etc. And the term "terra firma" has often been used in everyday usage. ←] <sup>'']''</sup> ]→ 11:34, 19 December 2024 (UTC)
			::::::: And yet, if you ask 1,000 people "What's that big yellow thing up in the sky called?", you'll get 1,000 "the Sun"s and zero "Sol"s. Yes, in specialised contexts, Sol is used; but that doesn't justify saying our solar system's star "is called Sol" without any qualification, as if that were the normal, default term. It's not. -- ] </sup></span>]] 12:16, 19 December 2024 (UTC)
			:::::::::And after you've gotten that response, ask them why it isn't the "Sunner System". And why a sun room attached to a house isn't called a "sunarium". And why those energy-gathering plates on some roofs are not called "sunner panels". ←] <sup>'']''</sup> ]→ 14:22, 19 December 2024 (UTC)
			::::::::::What does that have to do with anything? The question was 'Is our star system ''officially'' called "Sol"?' (my emphasis). The answer is it is not. And that does not preclude other terms being derived from Latin ''sol'' (or, often enough, from Greek ''helios''), nobody denies that, it is irrelevant to the question. --] (]) 14:52, 19 December 2024 (UTC)
			:::::::::::The problem is that the OP's question contains false premises. One is the question of what the "official" name is. There is no "official" name. It's the "conventional" name. And the second part, claiming that "Sol" comes from Sci-fi, is demonstrably false. ←] <sup>'']''</sup> ]→ 15:05, 19 December 2024 (UTC)
			::::::::::::Then demonstrate (that the usage of "Sol" as a name for the Sun, in English, not its use to derive adjectives, originated outside of SF), with references. The original question does not even include any premises, with maybe the exception of "ubiquitous". --] (]) 15:18, 19 December 2024 (UTC)
			:::::::::::::"Is our star system officially called "Sol" , or is that just something that came from science fiction and then became ubiquitous? ". And the wording of your own question, just above, does not make sense. ←] <sup>'']''</sup> ]→ 15:24, 19 December 2024 (UTC)
			::::::::::::::Looking at Newspapers.com (pay site), I'm seeing colloquial references to "old Sol" (meaning the sun) as far back as the 1820s. No hint of sci-fi derivation. ←] <sup>'']''</sup> ]→ 15:32, 19 December 2024 (UTC)
			:::::::::::::::Great! Well done. --] (]) 15:41, 19 December 2024 (UTC)
			::::::::::::::::Feel free to box up this section. ←] <sup>'']''</sup> ]→ 15:52, 19 December 2024 (UTC)
			:::::::::::::The 1933 OED entry for ''Sol'', linked to above, gives several pre-SF uses, the earliest from 1450.  --] 23:48, 19 December 2024 (UTC)
			::::::::::::::Yes, of course, but that's not surprising, is it? 15th century humanists, astrologers and pre-Victorian poets liked to sprinkle their texts with Latin words. But I don't think this is what the question is about. It's a matter of context, but it should be up to OP to clarify that. --] (]) 08:48, 20 December 2024 (UTC)
			:::::::::::::::It's not surprising, but the discussion was not whether the use of ''Sol'' in English texts is surprising, but whether it originated outside of SF.  --] 10:52, 20 December 2024 (UTC)
			::::::::::::::::In my view, the question has a clear scifi bent, and that particular usage ("Where shall we go for our vacation? Alpha Centauri or Sol?") does not originate in the 15th century. The word is much older, of course it is, but the usage is not. In the 15th century people didn't even know that the Sun is just an ordinary star and could do with a particular name to distinguish it from the others. The connotations of ''sol'' were vastly different from what they are today and from what is implied in OP's question. Incidentally, the ] doesn't even define a name , although they recommend using capitalised "Sun". Certainly no "Sol" anywhere. --] (]) 12:04, 20 December 2024 (UTC)
			::::::::{{small\|Does that make it a Sol-ecism? ] (]) 12:19, 19 December 2024 (UTC)}}
			:::::::::<small>More like a ]. Meaning a factory where suns are made. From Sol = sun, and ipso = facto. Thus endeth the entymogology lesson for today. Go in peace to love and serve whomsoever. -- ] </sup></span>]] 19:37, 19 December 2024 (UTC) </small>

			== Mountains ==
	:I can't believe that no-one has mentioned it earlier, but the ] of relevance here. ] (]) 13:39, 17 November 2014 (UTC)

			Why there are no mountains on Earth with a height above 10,000 m? As the death zone is about at 8,000 m, and above 19,000 m, there is an Armstrong limit, where water boils at normal human body temperature, it is good that there are no more mountains higher than 8,000 km than just 14, but if there were hundreds of mountains above 9,000 m, then these were bad to climb. If there were different limits for death zone and Armstrong limit, would then there be possible to have higher mountains? I have just thought that, it is not a homework? --] (]) 22:29, 18 December 2024 (UTC)
	== Plant respiration ==

			:There are ] that are over 20km high. Given that some of those are on airless worlds, I don't think the air pressure has any bearing on it. ] (]) 22:57, 18 December 2024 (UTC)
	Where can I find information about plant respiration? I'm looking for specific numbers which give plant respiratory rates during non-photosynthesis periods (aka night) for a variety of crops. A web search gives me several "online answers" type sites which suggest that plants give off CO2 at night at about 10% of the rate that they take it in during the day, but I've not been able to find anything more specific or anything at all authoritative. Our ] is a disambiguation page and ] doesn't have much useful to say. Do we have more on the subject? -- ] 14:18, 16 November 2014 (UTC)
	:Go to Google Scholar and do a search on "dark respiration." There's plenty of info out there. ] (]) 16:14, 16 November 2014 (UTC)
	::In addition, check out the equations and references used by , which is a mathematical model for plant physiological processes. The dark respiration model is explained here: . ] (]) 08:04, 17 November 2014 (UTC)
	:::Thank you very much, both of you. "Dark respiration" was certainly the term I need to be searching on. I haven't found a general table yet, but a few formulae suggest values greater than 10%. For instance, 's abstract states that clover and sorghum have a nightly efflux equal to 14% of the previous daytimes influx, plus and additional maintenance component of the efflux which is proportional to the dry weight of the plant, 1.43% of that weight for clover and 0.54% for sorghum (more details behind a paywall). And I appreciate being pointed to WIMOVAC, as it is mathematical modeling I am interested in. -- ] 12:44, 17 November 2014 (UTC)
	:::::Check out Ameriflux and FluxNet. You'll generally want empirical data more recent than 1974, as the ] tower technology has really changed how accurate measurements of dark respiration can be. Although it's not the primary mission, a lot of research on biofuels and greenhouse gas emissions associated with agricultural production will mention dark respiration numbers. So I'd also try searching google scholar for things like /dark respiration eddy covariance/ ] (]) 15:43, 17 November 2014 (UTC)
	::::::Here's a nice paper that covers dark respiration in few different crops . I actually know a small bit about the mathematical modeling of plant physiology (my research expertise is in applied math/theoretical ecology, and this stuff is tangentially related), so fee free to drop me a line at my talk page if you'd like to discuss further. ] (]) 17:46, 17 November 2014 (UTC)

			:Multiple sources from web searching suggest the ''theoretical'' maximum height for mountains on Earth is around 15,000 m – the limiting factor is ]; the higher (therefore more voluminous) a mountain is, the more its weight causes the crust beneath it to sink. The actual heights of mountains are a trade-off between how fast tectonic movements can raise them versus isostatic sinking ''and'' how quickly they are eroded, and tectonic movements do not last for ever. See also ]. {The poster formerly known as 87.81.230.195} ] (]) 00:25, 19 December 2024 (UTC)
	== Water on building demolition ==
			::And erosion goes faster as the mountain gets higher, in particular when it's high enough to support glaciers – one reason why mountains can get higher on an airless world. Now it gets interesting for a mountain high enough to reach into the stratosphere, as it would be too dry to have anything but bare rock. I suppose it would locally raise the tropopause, preventing that. ] (]) 11:13, 19 December 2024 (UTC)

			= December 19 =
	]

			== Does human DNA become weaker with each generation? ==
	What's the point of spraying water on a building demolition? Keeping down dust? Or should I simply assume that they had feared fire? Image context — it hadn't rained in a few days (this was last Tuesday, and there was a moderate rainstorm on the previous Saturday), with unusually high temperatures in the 60°s F, while "surrounding" days were in the 40°s and 30°s F. Although the demolition machine is pausing at the moment of the picture, the pause is momentary; its noise could be heard throughout the downtown for most of the afternoon. Water spraying continued, with both demolition machine and water hitting the building at the same time. ] (]) 15:11, 16 November 2014 (UTC)

			As with photocopying something over and over, the text becomes less clear each time.
	:Keeping dust down. Fire is unlikely to be caused by demolition, assuming they disconnected any natural gas lines first. ] (]) 15:21, 16 November 2014 (UTC)

			Does human DNA become weaker with each generation? ] (]) 21:22, 19 December 2024 (UTC)
	::For that matter, dust itself can be a ] if it happens to be flammable. Considering what the dust from a building demolition is likely to consist of, you wouldn't expect it to be flammable, but hey, who knows what those people had stored in there? --] (]) 09:05, 17 November 2014 (UTC)
			:Sure, DNA replication is not perfect, although ] reduces the error rate to about 1 mistake per 10<sup>9</sup> nucleotides (see our article on ]). But that is per generation of cells, not of the whole organisms. Many mutations will be neutral in effect (because much of our DNA is redundant), some will be deleterious, and a few might be advantageous. It is the process of natural selection that hinders the spread of deleterious mutations: sometimes this aspect is called ]. One thus usually expects a stable ] over time rather than that "DNA becomes weaker with each generation". Medical science is reducing the selection pressure against some mutations, which consequently may become more common. One of the problems for asexual organisms is referred to as ]; assuming that reverse mutations are rare, each generation has at least the mutational load of its predecessor. In contrast, in sexual organisms ] generates the variation that, combined with selection, can repair the situation. Sexual organisms consequently have a lighter genetic load. ] (]) 22:42, 19 December 2024 (UTC)
			::So ] won't work properly in case of ] ? ] (]) 23:16, 19 December 2024 (UTC)
			:::The larger the degree of inbreeding, the larger the chance that deleterious traits are expressed. But this very expression of traits leading to decreased biological fitness of their bearers is what actually enables purifying selection in the longer term.  --] 23:36, 19 December 2024 (UTC)
			::::@] so ] won't stop these deleterious traits to get expressed? ] (]) 14:11, 20 December 2024 (UTC)
			:::::No, this is not an issue of ]. The genes involved are faithfully reproduced and passed on from generation to generation.  --] 15:53, 20 December 2024 (UTC)
			:Or stronger e.g. "", and those guys live for centuries and have much more DNA than us. ] (]) 15:21, 20 December 2024 (UTC)
			::@] If not due to DNA damage, why do babies from inbreeding appear like DNA-damaged species? ] (]) 17:29, 20 December 2024 (UTC)
			:::Inbred offspring of species that normally outcross may show abnormalities because they are more likely than outcrossed offspring to be ] for ] that are deleterious. In individuals that are heterozygous at these loci, the recessive alleles will not be expressed (because the other wild-type dominant allele is sufficient to do their job adequately). See our article on ]. ] (]) 19:26, 20 December 2024 (UTC)

			== Larvae going south ==
	:We even have an article: ]. Some cities or counties require spraying water on certain types of construction sites. As I recall, in North Carolina, where water was plentiful, they would even spray down the ground around the construction site. ] (]) 15:54, 16 November 2014 (UTC)

			In a novel I've just finished ('']'' by ]) he writes:
	:Many old houses have asbestos, mold and other toxic material, you don't want that dust to fly to the neighborhood ] (]) 17:50, 16 November 2014 (UTC)
			* '' leave the body in an orderly fashion, following each other in a neat procession that always heads south. South-east or south-west sometimes, but never north. No-one knows why''.
	::My city requires it as well (] - Israel). The reason is as mention above: to keep dust down and to prevent the dust of the environment.] (]) 18:01, 16 November 2014 (UTC)
	:::I doubt that if the building has asbestos, just springling water will be enough. Demolishing and decontaminating asbestos contructions is more difficult than that.] (]) 18:53, 16 November 2014 (UTC)
	::::See of the building; it's a ] structure probably newer than US federal laws restricting asbestos usage. ] (]) 03:31, 17 November 2014 (UTC)

			The author has done considerable international research on the science of forensic identification of decayed bodies and I assume his details can be trusted.
	== what is the difference between potentiation and synergism? (pharmacology) ==

			I've looked online for any verification of this surprising statement, but found only , which seems to debunk it.
	] (]) 17:57, 16 November 2014 (UTC)

			Is there any truth to this? -- ] </sup></span>]] 23:38, 19 December 2024 (UTC)
	:Is this a homework question?<br>
	:Let's take a practical example. To make vaccines more potent aluminium compounds are often added. These compounds on their own have no anti-viral effect. ] in antibiotic is another example. Synergism is were 'both' substances have an effect. For example: Alcohol and barbiturates are both depressants, Taken together, the depressant effect is greater because they work together.<small> Incidentally, If one gets a pain around where the liver is, up to <u>two weeks after</u> finishing taking a clavulanic acid enhanced antibiotics, see your doctor to have a ] submitted. In the US it would be these people: This bad reactions appears to be under reported. These enhanced antibiotics should not be used as a first line treatments IMHO. I'm not giving medical advice but directing readers to a professional.</small>.--] (]) 18:52, 16 November 2014 (UTC)

			:Can't speak to its truth, but . . .
	== Proper adhesive ==
			:* Does Beckett state this in his own auctorial voice (i.e. as an ])? If so, he might be genuinely mistaken.
			:* The book was published nearly 20 years ago, what was the accepted wisdom ''then''?
			:* What specific species (if any) is the book describing? – your linked Quora discussion refers only to "maggots" (which can be of numerous species and are a kind of larva, but there are many others, including for example ]).
			:*Alternatively, if the statement is made by a character in the book, is that character meant to be infallible, or is he portrayed as less than omniscient, or an ']'?
			:Regarding the statement, in the Northern hemisphere the arc of South-east to South-west is predominently where the Sun is found well above the horizon, the North never, so the larvae involved might simply be seeking maximum warmth or light. {The poster formerly known as 87.81.230.195} ] (]) 02:18, 20 December 2024 (UTC)

			:: This appears in the very first paragraph of Chapter I, which starts out:
	I have decided to make myself a custom tea infuser but I am struggling to find a proper adhesive for that purpose.
			::* ''A human body starts to decompose four minutes after death. Once the encapsulation of life, it now undergoes its final metamorphoses. It begins to digest itself. Cells dissolve from the inside out. Tissue turns to liquid, then to gas. No longer animate, the body becomes an immovable feast for other organisms. Bacteria first, then insects. Flies. Eggs are laid, then hatched. The larvae feed on the nutrient-rich broth, and then migrate. They leave the body in an orderly fashion ...'' (then the quote above completes the paragraph).
	Is there any glue for plastic that can have a direct contact with food and withstand up to 100 °C?
			:: It's not until para 2 that he starts talking about any human characters, and not until para 4 that he invokes the first person.
	Will ] do? It works for plastic. Water does not do much to it either. It must be non toxic as is used in medicine. But I failed to find info on how toxic it actually is other than its fumes may be dangerous. Another doubt is about the temperature it can withstand as I don't have much data no that. ] (]) 21:46, 16 November 2014 (UTC)
			:: That's as much as I know. But I find it hard to believe he'd just make up a detail and put it in such a prominent place if it could so easily be debunked if it were not true. -- ] </sup></span>]] 02:39, 20 December 2024 (UTC)
			:::I wonder how they would measure the migratory path of maggots within a sealed coffin. ←] <sup>'']''</sup> ]→ 02:51, 20 December 2024 (UTC)
			:::: The context of the novel is about finding decaying corpses that have been dumped in a forest. No coffins involved. -- ] </sup></span>]] 06:08, 20 December 2024 (UTC)
			::::::], see also ] research facilities. ] (]) 13:44, 20 December 2024 (UTC)
			:::::Could it be that the larvae are setting off in search of another corpse? The prevailing wind in the UK is from the south-west, so by heading into the wind they won't be distracted by the frangrance of the one they've just left. ]\|] 09:30, 20 December 2024 (UTC)

			If you can, have a look at 'Heinrich, Bernd. “Coordinated Mass Movements of Blow Fly Larvae (Diptera: Calliphoridae).” Northeastern Naturalist, vol. 20, no. 4, 2013, pp. N23–27. JSTOR, http://www.jstor.org/stable/43288173.' Here are some extracts
	:'''''Groan'''''....Epoxied resins are probably better as they are also stronger and the right ones are biologically inert. See: Personally, I would just use a proper ] and use real, genuine, lose leaf tea. See:] . Read and do! Lastly, enjoy your first cup of real tea. If you like milk, put it in the cup 'first'. No augments! Milk first.--] (]) 22:40, 16 November 2014 (UTC)
			* On the fourth day, after a cooling night with dew on the grass, a stream of tens of thousands of larvae exited from beneath the carcass within 1 h after sunrise, and proceeded in a single 1-2-cm-wide column directly toward the rising sun...
			* However, in this case, the larvae left at night, within 1 h after a cloudburst (at 21 :00 hours). But, unlike before, this nocturnal larval exodus in the rain was diffuse; thousands of larvae spread out in virtually all directions over an 8 m2area. Apparently, the sudden moisture had cued and facilitated the mass exodus, but the absence of sun had prevented a unidirectional, en masse movement.
			* However, on the following morning as the sun was starting to illuminate the carcass on the dewy grass, masses of larvae gathered at the east end of the carcass at 07:00 hours. In one half hour later, they started streaming in a column directly (within one degree) toward the rising sun, and the carcass was then nearly vacated.
			It goes on. Maggot migration appears to be a bit more complicated than the novel suggests. ] (]) 09:39, 20 December 2024 (UTC)
			I suppose you could try to address it from the other direction and look at the technology your average maggot has access to in terms of light detection, heat detection, olfactory systems, orientation in magnetic fields (like many arthropods) etc. They presumably have quite a lot of tools. ] (]) 10:13, 20 December 2024 (UTC)

			:If orderly migrating maggots tend to move towards the sun, they should display a northward tendency in Oztralia.  --] 10:31, 20 December 2024 (UTC)
	:How about just buying a ] ? ] (]) 22:46, 16 November 2014 (UTC)
			:: Maybe, but the novel is set in England.
			:: I must say, as soon as I read the quoted para for the first time, my immediate thought was that it might have something to do with the magnetic field of the earth. -- ] </sup></span>]] 10:42, 20 December 2024 (UTC)
			:::Prime suspect might be the Bolwig organ, the photoreceptor cluster many fly larvae have. ] (]) 10:49, 20 December 2024 (UTC)
			:::Obviously, Jack, you need to create a corpse, place it in a nearby forest, and carefully observe which way the maggots go. For Science! And Literary Criticism! {The poster formerly known as 87.81.230.195} ] (]) 21:01, 20 December 2024 (UTC)

			= December 20 =
	::Sacrilege! The leaves need to circulate. A ] employed during the pouring out, shows one guests that you now how to brew a really good steaming hot cup of tea. Otherwise, you might just as well serve them up with something from a vending machine which fills the cup up with a liquid that is almost, but not quite, entirely unlike tea.--] (]) 23:18, 16 November 2014 (UTC)

			== Winter solstice and time of sunrise? ==
	::<small>I have given up asking for a cup of tea in the US because all I get is a cup of lukewarm water and a pouch dangling on the end of a string and a little plastic thing that is supposed to contain cow juice but no cup of tea in sight ''and then'' they have the nerve to bill me for over a dollar for something that is only good as an insecticide. How is it, that a nation can put a man on the moon but can't achieve the simple art of brewing tea?--] (]) 23:35, 16 November 2014 (UTC)</small>

			How is it that despite December 21st supposedly being the shortest day of the year, sunrise here happens later and later until December 26 and only on January 05 starts to turn around to occur earlier and earlier. On December 25 it takes place at about 08:44, between December 26 and January 04 it takes place at about 08:45, and on January 05 it takes place again at about 08:44. (Google rounds out the seconds). Is it Google's fault? Is it everywhere the same? Confused in Brussels, Belgium. ] (]) 12:06, 20 December 2024 (UTC)
	:::<small>Some might argue that the time saved over not obsessing over the precise formulation of warm water with tiny shrivelled up leaves in it is precisely what enabled them to reach the moon. The British effort to get to the moon foundered on the heated debate of when to add the milk in a micro-gravity environment. But then, I'm a Brit who can't stand even the smell of tea...YUCK! ] (]) 04:55, 17 November 2014 (UTC)</small>
			:The pertinent article is ], start with the section ]. The details are not that simple to understand, but it's basically due to the ellipticity of Earth's orbit and its axial tilt. --] (]) 12:22, 20 December 2024 (UTC)
			::Also note that sunset begins to be later on 22 December so that the time between sunrise and sunset is a few seconds longer than on 21 December (3 seconds longer on 22/12/24 in Brussels according to ). ] (]) 13:33, 20 December 2024 (UTC)
			::Also see ]. The obliquity of the ecliptic (that is, the Earth's axial tilt) is the main component and hardest to understand. But the idea is that the time when the Sun is exactly south (that is, the true noon) moves some minutes back and forth throughout the year and it moves quite rapidly to later times in late December. ] (]) 19:05, 20 December 2024 (UTC)

			== Three unit questions ==
	::::<small>Astronauts made their way to the moon as the result of the efforts of a small group of people. Saying it was the nation that sent them to the moon is an example of ]. Similarly, the nation has never made, or attempted to make, a cup of tea. Cups of tea are made by individuals, not nations. ] ''(])'' 05:31, 17 November 2014 (UTC)</small>

			# Why territorial waters are defined by nautical miles instead of kilometers?
	:::::<small>I disagree. Sending the first man to the Moon required that massive tax dollars be spent on the project, which required a large, wealthy population, with the political will to spend that money in that way (or a dictator who gave them no choice). ] (]) 19:49, 17 November 2014 (UTC) </small>
			# Why GDP is usually measured in US dollars rather than euros? Euro would be better because it is not tied into any country.
	:::::<small>Um...<small> comments are intended to be jokes - no need to take them so seriously. Of course a small group of people were responsible for all of the bravery, the clever science and engineering it took to get to the moon - and a very large number of people had to have the collective will to vote for politicians that wouldn't cancel the entire thing...but remember the <small><small> font</small>! ] (]) 20:39, 17 November 2014 (UTC)</small>
			# Are there any laws in United States that are defined by metric units?
			--] (]) 23:30, 20 December 2024 (UTC)
			:#There were nautical miles in use before there were kilometers.
			:#There were US dollars in use before there were Euros.
			:#Yes.
			:The questions all reduce to Why can't millions of people make a change of historically widely accepted units that continue to serve their purpose, and convert to different units that would have no substantive difference, because someone has an opinion. ] (]) 00:52, 21 December 2024 (UTC)
			::Do any people use metric units in marine and air navigation like "The ship is 10 kilometers from the port", "The plane is 10 kilometers from the destination? And is there any European country with metric flight levels? --] (]) 07:22, 21 December 2024 (UTC)
			:::Inland shipping (rivers, canals and lakes) in Europe (except the UK) is fully metric. Ships going for example ] – ] may have to switch units along the way. Gliders and ultralight aircraft in Europe often use metric instruments and airport dimensions are also metric (including runway length). Countries are free to define their territorial waters in whatever way they deem fit, so with nautical miles having no legal status in a fully metric country, they may define their territorial waters as extending 22224 metres. ] (]) 11:23, 21 December 2024 (UTC)
			::::Our ] article says: {{xt\|"In 1929 the international nautical mile was defined by the First International Extraordinary Hydrographic Conference in Monaco as exactly 1,852 metres (which is 6,076.12 ft). The United States did not adopt the international nautical mile until 1954. Britain adopted it in 1970..."}}
			::As the US customary units are actually defined in terms that relate them to metric units, any US law based on measurements is technically defined by metric units.--] (]) (]) 01:55, 21 December 2024 (UTC)
			:::The US dollar has been the world's dominant ] for about 75 years. As for the metric system in the US, it is standard in scientific, medical, electronics, auto manufacturing and other highly technical industries. By law, all packaged foods and beverages have metric quantities as well as customary quantities. See ]. ] (]) 02:28, 21 December 2024 (UTC)
			The Wikipaedia article on the Nautical Mile talks about how the term originated, it was originally defined in terms of latitude not as a number of meters ] (]) 10:03, 24 December 2024 (UTC)

			The euro is tied to multiple specific countries is it not? If you use euros you're just changing from one "dependency" to a "dependency" on the ] countries. A statement of the problem or problems intended to be addressed would be useful. Currency values are interconvertible in any case. Economics does sometimes use the "]" for certain things, which is intended to adjust for differences in ] between countries and over time. But since it's not an actual "real" currency it's not something one can easily "visualize" in their heads, which is likely why it's not used more. --] (]) 05:41, 26 December 2024 (UTC)
	:Which plastic? Different plastics need different glues, but in general it's impossible to glue plastic. Cyanoacrylate won't glue plastic very well, truthfully nothing will.
	:Usually you can use acetone to dissolve the plastic, put the pieces together and wait for the acetone to evaporate, and then they are one piece. (That's how commercial PVC glues work.) Acetone is pretty non-toxic and evaporates really well, so that would be safe for food use. ] (]) 06:22, 17 November 2014 (UTC)
	::I own and operate a small business providing a set of very specialized repair services to the construction and home improvement industry in the United States. It is impossible to generalize about "plastics" in a question like this. The performance of adhesives on polyethylenes is completely different from the performance of the same adhesives on polystyrenes. I work most commonly with mineral filled sheet acrylic products, and sometimes with polyester/acrylic blends. In the past, I worked with plastic laminates, where rubber based "contact adhesives" are used routinely, but where urethane adhesives are used in higher-end custom work. In my day to day work, when high performance and a highly inconspicuous seam is critical, we use catalyzed acrylic adhesives most commonly, which we purchase in a wide range of color tints to match the background color of the sheet product. For rapid but more visible bonds, we often use cyanoacrylates. Silicone provides a very strong, flexible bond, but that is not truly inconspicuous. We use hot melt adhesives for temporary tacking and "clamping" but they shouldn't be considered permanent in exposed situations, as exposure to alcohol (such as vodka) will cause the glue line to fail. Construction adhesives (called "panel adhesives" in the U.S.) are strong, inexpensive but ugly. In our line of work, we rarely use epoxies these days, and their performance characteristics vary. Also worthy of mention are UV cured "dental grade" adhesives, which can be tinted and filled with particulates to simulate the substrate, leading to very inconspicuous bonds. Selection of the best adhesive is always a trade-off of factors including compatibility with the material being bonded, strength, appearance, cost, cure time, flexibility, toxicity, availability and things I have forgotten this late at night. There are no easy answers in this area. By the way, acetone is not non-toxic. Sorry. ] ] 07:15, 17 November 2014 (UTC)
	::::Actually ] is pretty much non-toxic. People are always surprised when they hear this, but go and look it up and you'll see. The reason it's mostly non-toxic is that the body naturally contains some, and is able to metabolize it rapidly. (It's not completely non-toxic, don't go drinking it, but as solvents go it's very safe. It's certainly safe to use as a glue and then let it dry.) ] (]) 19:09, 17 November 2014 (UTC)
	:::I'm not nearly as well-versed about plastics as ] sounds, but I strongly endorse several of his points: "plastic" refers to ''many hundreds'' of different types of material. Even if we consider only those plastics that are readily available to consumers, there are ''many'' categories. If we use ]s as a guideline, we can loosely group consumer-grade plastic into six general "types" plus a catch-all "other" category. These categories are ''completely different'' kinds of chemicals!
	:::Just for fun, I checked the FDA's web-page for food-safe adhesives. They linked to . In the United States, food-grade adhesives must come from that list of pre-approved chemicals; but there is the wonderful catch-all phrase that you will find in almost all FDA regulatory writing, permitting all "substances for use in food." In concept, if you used one of these chemicals, your product would be ''compliant with food safety regulations'' - which is, needless to say, conceptually distinct from a product that is ''actually safe.'' ] is ''not'' on the listing in 21 CFR 175 §105 c(5) and I doubt it meets GRAS requirements. I would wager that cyanoacrylate is ''neither compliant nor safe'' for use in food products. ] publishes a ] for (the kind of CYA glue you'd buy in a hobby model-store). Among the statements in the MSDS: "Not expected to be harmful by ingestion"; "The product will polymerize rapidly and bond to the mouth making it almost impossible to swallow. Saliva will separate any solidified product in several hours. Prevent the patient from swallowing any separated mass;" "Surgery is not necessary to separate accidentally bonded tissues. Experience has shown that bonded tissues are best treated by passive, non-surgical first aid." So, if you follow the advice of this vendor, ... it ''should'' be harmless!
	:::If I were building a home-made apparatus for brewing hot beverages for my own consumption, I would be ''very'' careful about the materials and glues I used. I would avoid cyanoacrylate entirely.
	:::] (]) 18:17, 17 November 2014 (UTC)

	= ~~November~~ 17 =		= December 24 =

			== Unknown species of insect ==
	== Just asked for a clarification at ] ==

			Am I correct in inferring that ] this guy is an ]? I was off-put by the green head at first, but the antennae seem to match. ''']]''' 03:00, 24 December 2024 (UTC)
	Please see. ] (]) 08:17, 17 November 2014 (UTC)
	:The articles on the individual UCPs listed there each have a brief (or not-so-brief) description of the process. Some are copy-paste wording, others have more/different details. At a minimum, the set of articles should be refactored to centralize the description of this process on its own page. ] (]) 08:28, 17 November 2014 (UTC)

			(reference: https://www.genesdigest.com/macro/image.php?imageid=168&apage=0&ipage=1)
	== Soapy water ==

	~~What~~ ~~actually~~ ~~happens~~ to the ~~soapy~~ ~~water~~ that ~~gets~~ on ~~the~~ ~~bathroom~~ ~~floor~~ ~~when~~ ~~people~~ ~~are washing their hands~~. ~~Does the soap component just evaporate with water?~~ ] (]) 20:14, 17 ~~November~~ ~~2014~~ (UTC)		:<s>It looks like one of the invasive ]s that happens to like my blackberries in the summer.</s> ] (]) 13:11, 24 December 2024 (UTC)

			::I would say not necessarily a Japanese beetle, but almost certainly one of the other ] beetles, though with 35,000 species that doesn't help a lot. Looking at the infobox illustration in that article, 16. & 17., "]" looks very similar, but evidently we either don't have an article or (if our ] article is a complete list) it's been renamed. {The poster formerly known as 87.81.230.195} ] (]) 14:18, 24 December 2024 (UTC)
	:No. The water evaporates away and the soap is left behind, often leaving a greasy or grimy feel. Same concept as ]. ] (]) 21:21, 17 November 2014 (UTC)

			:::Yes, it's not the Japanese beetle for this beetle appears to lack its white-dotted fringe although its condition is deteriorated. Its shape is also more or less more slender; and not as round. ] (]) 15:02, 24 December 2024 (UTC)
	== Gravitation / Relativity / Cosmology ==

			:Perhaps it is the ] ]. Shown . ] (]) 16:09, 24 December 2024 (UTC)
			::That looks like easily the best match I've seen so far, and likely correct. {The poster formerly known as 87.81.230.195} ] (]) 17:09, 24 December 2024 (UTC)

			= December 25 =
	Hello,

			== Mass of oscillating neutrino ==
	If we compare times between altitudes, we see a gap time. (General Relativity)

			From the ] it follows that a particle that is not subject to external forces must have constancy of mass.
	Why don't we see differences in the pictures of the skies ?

			If I am right, this means that the mass of the neutrino cannot change during the ], although its flavoring may. Is this written down somewhere? Thank you. ] (]) 19:24, 25 December 2024 (UTC)
	Thank you for your answers.
			:Any (flavored) neutrino that is really observed is a superposition of two or three mass eigenstates. This is actually the cause of ]. So, the answer to your question is complicated. ]_] 19:40, 25 December 2024 (UTC)
			:Important note: particle physicists today generally only ever use "mass" to mean "]" and never anything else: . Like the term says, invariant mass is well, invariant, it never changes ever, no matter what "external forces" may or may not be involved. Being proper particle-icans and following the standard practice in the field, then, the three neutrino masses are constant values. ..."Wait, three?" Yeah sure, turns out ]. As mentioned, due to Quantum Weirdness we aren't able to get these different states "alone by themselves" to measure each by itself, so we only know the differences of the squares of the masses. Yeah welcome to quantum mechanics.
			:]: "Quantum mechanics describes nature as absurd from the point of view of common sense. And yet it fully agrees with experiment. So I hope you can accept nature as She is {{snd}} absurd." --] (]) 06:06, 26 December 2024 (UTC)
			::The equation <math>E^2 = (p c)^2 + \left(m_0 c^2\right)^2</math> uses invariant mass {{math\|''m''<sub>0</sub>}} which is constant if {{math\|''E''}} and {{math\|''p''}} are constant. The traveling neutrino has a varying mass mixture of different flavors with different masses. If a mixture of different masses changes, you would expect the resulting mass to change with it. But somehow this does not happen as the neutrino mass mixture changes. These mixture changes cannot be any changes. The changes must be such that the resulting mass of the traveling neutrino remains constant. My question is whether this is described somewhere. ] (]) 11:16, 26 December 2024 (UTC)
			:::I freely confess I'm uncertain exactly what's being "asked for" or "gotten at" here. Have you looked at the ] article? From it: {{tpq\|That is, the three neutrino states that interact with the charged leptons in ]s are each a different ] of the three (propagating) neutrino states of definite mass. Neutrinos are emitted and absorbed in weak processes in flavor ]s '''but travel as mass eigenstates.'''}}
			:::What is it that we're "doing" with the ] here? For the neutrino, we don't have a single value of "mass" to plug in for <math>m_0</math>, because we can't "see" the individual mass eigenstates, only some ] of them. What you want for describing neutrino interactions is ], which is special relativity + QM. (Remember, relativity is a "classical" theory, which presumes everything always has single well-defined values of everything. Which isn't true in quantum-world.) --] (]) 18:41, 26 December 2024 (UTC)
			::::Not all potential evolutions of a linear combination of unequal values produce constant results. Constancy can only be guaranteed by a constraint on the evolutions. Does the fact that this constraint is satisfied in the case of neutrino oscillation follow from the ], or does this formulation allow evolutions of the mass mixture for which the combination is not constant? If the unequal values are unknown, I have no idea of how such a constraint might be formulated. I think the OP is asking whether this constraint is described somewhere.  --] 00:51, 27 December 2024 (UTC)

	:The differences are very very tiny...a truly microscopic fraction of a second. ] (]) 21:13, 17 November 2014 (UTC)

			= December 27 =
	Should there not be an accumulation of time ?
	::Please be more specific as to what accumulation of time you expect. As Steve Baker said, even over a very long period of time, the time dilation effect of general relativity can only be measured with extremely precise and sophisticated equipment. I think that even if you do the arithmetic for an accumulation of time, it will be too small to observe except with equipment designed for the purpose of observing the effect. ] (]) 21:35, 17 November 2014 (UTC)

			== Low-intensity exercise ==
	== the value of a 0.022K capacitor? ==

			If you exercise at a low intensity for an extended period of time, does the ] still occur if you do it for long enough? Or does it only occur above a certain threshold intensity of exercise? ] (]) 20:13, 27 December 2024 (UTC)
	i have got non polarized polyester capacitior which has "0.022K400V" printed on it.
			:Hows about you try it and report back? :) ←] <sup>'']''</sup> ]→ 21:31, 27 December 2024 (UTC)
	what is the value of cap in uF?
	:That's a 0.022 µF capacitor rated for 400V. The letter "K" denotes 10% tolerance. I see that the wiki page on ] is pretty slim. See for an explanation of component markings. ] (]) 21:31, 17 November 2014 (UTC)

Latest revision as of 21:31, 27 December 2024

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December 13

What is the most iconic tornado photo

Request for opinions
The following discussion has been closed. Please do not modify it.
What photo of a tornado would you say is the most iconic? I'm researching the history of tornado photography for an eventual article on it and I've seen several specific tornadoes pop up over and over again, particularly the Elie, Manitoba F5 and the "dead man walking" shot of the Jarrel, Texas F5. Which would be considered more iconic? ApteryxRainWing🐉 \| Roar with me!!! \| My contributions 17:21, 13 December 2024 (UTC) At the top of this page is a bullet point stating "We don't answer requests for opinions, predictions or debate": this reads to me like a request for subjective opinions. Perhaps you would like to consider what quantifiable and referenceable metric would answer what you want to know? Presumably you also want only real tornadoes considered? Otherwise some might nominate the the twister from The Wizard of Oz, or from more recent tornado-related movies – Sharknado, anyone? :-). {The poster formerly known as 87.81.230.195} 94.1.223.204 (talk) 18:07, 13 December 2024 (UTC) "Swegle Studios" has a couple of YouTube videos dedicated to the backstories of famous tornado photos and video; you might find them useful in your research. Photos, Videos. Matt Deres (talk) 18:40, 13 December 2024 (UTC) I googled "most iconic tornado photo" and a bunch of different possibilities popped up. I don't see how you could say that any given photo is the "most iconic". ←Baseball Bugs carrots→ 18:57, 13 December 2024 (UTC)

Request for opinions

The following discussion has been closed. Please do not modify it.

What photo of a tornado would you say is the most iconic? I'm researching the history of tornado photography for an eventual article on it and I've seen several specific tornadoes pop up over and over again, particularly the Elie, Manitoba F5 and the "dead man walking" shot of the Jarrel, Texas F5. Which would be considered more iconic? ApteryxRainWing🐉 | Roar with me!!! | My contributions 17:21, 13 December 2024 (UTC)

At the top of this page is a bullet point stating "We don't answer requests for opinions, predictions or debate": this reads to me like a request for subjective opinions. Perhaps you would like to consider what quantifiable and referenceable metric would answer what you want to know?

Presumably you also want only real tornadoes considered? Otherwise some might nominate the the twister from The Wizard of Oz, or from more recent tornado-related movies – Sharknado, anyone? :-). {The poster formerly known as 87.81.230.195} 94.1.223.204 (talk) 18:07, 13 December 2024 (UTC)

"Swegle Studios" has a couple of YouTube videos dedicated to the backstories of famous tornado photos and video; you might find them useful in your research. Photos, Videos. Matt Deres (talk) 18:40, 13 December 2024 (UTC)

I googled "most iconic tornado photo" and a bunch of different possibilities popped up. I don't see how you could say that any given photo is the "most iconic". ←Baseball Bugs carrots→ 18:57, 13 December 2024 (UTC)

December 15

help to identify File:Possible Polygala myrtifolia in New South Wales Australia.jpg

Did I get species right? Thanks. Gryllida (talk, e-mail) 06:56, 15 December 2024 (UTC)

FWIW, I can't detect any visible differences between the plant in this photo and the ones illustrated in the species and the genus articles. However, the latter makes it clear that Polygala is a large genus, and is cultivated, with hybrids, so it's possible that this one could be a close relative that differs in ways not visible here, such as in the bark or roots. That may or may not matter for your purposes. {The poster formerly known as 87.81.230.195} 94.1.223.204 (talk) 10:11, 15 December 2024 (UTC)

How to address changes to taxonomy

Hi all, I am a biology student brand new to wiki editing who is interested in cleaning up small articles/stubs for less known taxa. One that I've encountered is a mushroom that occurs in the pacific northwest (Fomitopsis ochracea). The article mentions that this fungus is occasionally mistaken for another fungus, Fomitopsis pinicola.

However, the issue I've run into is that F. pinicola used to be considered a single species found around the world, but relatively recently was split into a few different species. The original name was given to the one that occurs in Europe, and the one in the pacific northwest (and thus could be mistaken for F. ochracea) was given the name Fomitopsis mounceae.

The wiki page says

Historically, this fungus has been misidentified as F. pinicola. When both species are immature, they can look very similar, but can be distinguished by lighting a match next to the surface of the fungus. F. pinicola will boil and melt in heat, while F. ochracea will not.

Since the source says pinicola (as likely do most/all other sources of this info given the change was so recent), and since technically it's true that they used to be mistaken for it... what would be the most appropriate way to modernize that section?

My questions are: Should I replace F. pinicola with F. mounceae? Or is that wrong because the source doesn't refer to it by that name? Would it be better to write something like (now known as/considered F. mounceae) next to the first mention of the species? Or is that a poor choice because it implies all the members of F. pinicola were renamed F. mounceae?

Any advice on how to go about updating this section is incredibly appreciated
TheCoccomycesGang (talk) 10:21, 15 December 2024 (UTC)

First, take these sorts of questions to the relevant Wikiproject, in this case Misplaced Pages talk:WikiProject Fungi. I am not as familiar with the consensus at WP:FUNGI, but it seems like they defer to Species Fungorium/Index Fungorium and Mycobank to decide. Those sources presently seem to consider Fomitopsis pinicola a good species. Also, be careful about "replacing", there are rules to ensure the continuity of the article history. By the way, there is a hilarious but unencyclopedic/copyvio recipe appended to the Fomitopsis mounceae article. Abductive (reasoning) 11:09, 15 December 2024 (UTC)

Thanks for the tips, I didn't know about projects so I'll go read up on that. And thanks for the warnings about replacing things. I've been reading a lot of help pages, but I'm still in the process of learning the all conventions and what mechanics break if you do things the wrong way.

I actually saw the recipe ages ago before I made my account and completely forgot about it... it was one of many things that prompted me to get into wiki editing. TheCoccomycesGang (talk) 23:12, 15 December 2024 (UTC)

Does stopping masturbation lead to sperm DNA damage?

I'm looking for information on the potential link between the frequency of ejaculation (specifically through masturbation) and sperm DNA damage. I've come across some conflicting information and would appreciate it if someone could point me towards reliable scientific studies or reviews that address this topic.

Specifically, I'm interested in whether prolonged periods of abstinence from ejaculation might have any negative effects on sperm DNA integrity. Any insights or links to relevant research would be greatly appreciated. HarryOrange (talk) 17:08, 15 December 2024 (UTC)

Only males may abstain from sperm-releasing Masturbation that serves to flush the genital tract of old sperm that in any case will eventually dissipate. No causal relationship between masturbation and any form of mental or physical disorder has been found but abstinence may be thought or taught to increase the chance of wanted conception during subsequent intercourse. Philvoids (talk) 00:51, 16 December 2024 (UTC)

There's many rumors about that topic. One is that not ejaculating frequently increases the risk of developing prostate cancer. Abductive (reasoning) 01:02, 16 December 2024 (UTC)

Nothing really conclusive but there's some evidence that short periods are associated with lower DNA fragmentation, see

Du, Chengchao; Li, Yi; Yin, Chongyang; Luo, Xuefeng; Pan, Xiangcheng (10 January 2024). "Association of abstinence time with semen quality and fertility outcomes: a systematic review and dose–response meta‐analysis". Andrology. 12 (6): 1224–1235. doi:10.1111/andr.13583. ISSN 2047-2919.
Hanson, Brent M.; Aston, Kenneth I.; Jenkins, Tim G.; Carrell, Douglas T.; Hotaling, James M. (16 November 2017). "The impact of ejaculatory abstinence on semen analysis parameters: a systematic review". Journal of Assisted Reproduction and Genetics. 35 (2): 213. doi:10.1007/s10815-017-1086-0. ISSN 2047-2919. PMC 5845044. PMID 29143943.
Ayad, Bashir M.; Horst, Gerhard Van der; Plessis, Stefan S. Du; Carrell, Douglas T.; Hotaling, James M. (14 October 2017). "Revisiting The Relationship between The Ejaculatory Abstinence Period and Semen Characteristics". International Journal of Fertility & Sterility. 11 (4): 238. doi:10.22074/ijfs.2018.5192. ISSN 2047-2919. PMC 5641453. PMID 29043697.

for example. Alpha3031 (t • c) 02:12, 16 December 2024 (UTC)

Mature sperm cells do not have DNA repair capability. Inevitably, as sperm cells get older, they will naturally and unavoidably be subject to more and more DNA damage. Obviously, freshly produced spermatozoa will, on average, have less DNA damage. It is reasonable to assume that the expected amount of damage is proportional to the age of the cells, which is consistent with what studies appear to find. Also, obviously, the more the damage is to a spermatozoon fertilizing an oocyte, the larger the likelihood that the DNA repair in the resulting zygote, which does have DNA repair capability, will be incomplete. The studies I've looked at did not allow me to assess how much this is of practical significance. --Lambiam 09:40, 16 December 2024 (UTC)

December 16

Abelian sandpile model

Thanks to those who answered my last question, I think it should be added to a disambiguation page. If anyone wants to help me write that, reach out.

A sandpile seems disorganized and inert, but these are critically self-organizing. Do the frequency and size of disturbances on sand dunes and snowy peaks follow power law distribution? Gongula Spring (talk) 01:18, 16 December 2024 (UTC)

Shouldn't this be at the Math Desk? Abductive (reasoning) 05:12, 16 December 2024 (UTC)

If the question is not about the model mentioned in the heading but about the physical properties of sand dunes and snowy peaks, this here is the right section of the Reference desk. --Lambiam 08:51, 16 December 2024 (UTC)

I await a non-mathematical answer. Abductive (reasoning) 09:23, 16 December 2024 (UTC)

It depends is probably a fairly reasonable non-mathematical answer for these kinds of systems. For sand dunes anyway, sometimes avalanche frequency is irregular and the size distribution follows a power law, and sometimes it's close to periodic and the avalanches span the whole system. It seems there are multiple regimes, and these kinds of systems switch between them. Sean.hoyland (talk) 09:35, 16 December 2024 (UTC)

Thank you! I'm impressed this seems so casual, but surely you read this somewhere that might have a URL?

Gongula Spring (talk) 22:29, 19 December 2024 (UTC)

Hi, this is an interesting and somewhat open question! A lot of work is done on these models but much less on careful analyses of real dunes. I did find this dissertation that is freely accessible and describes some physical experiments and how well they fit various models. The general answer seems to be that the power law models are highly idealized, and determining the degree to which any real system's behavior is predicted by the model ahead of time is very difficult. Update: This is one of the earlier important works on the topic and it does include discussion of how well the model fits experiments.SemanticMantis (talk) 17:21, 16 December 2024 (UTC)

That dissertation is great!

Gongula Spring (talk) 22:30, 19 December 2024 (UTC)

Polar night

Are there any common or scientific names for types of polar night? The types that I use are:

polar night - meaning a day when sun's altitude remains below horizon entire day (there is no daylight at solar noon, only civil twilight), occurring poleward from 67°24′ north or south
civil polar night - meaning a day when sun's altitude remains below -6° entire day (there is no civil twilight at solar noon, only nautical twilight), occurring poleward from 72°34′ north or south
nautical polar night - meaning a day when sun's altitude remains below -12° entire day (there is no nautical twilight at solar noon, only astronomical twilight), occurring poleward from 78°34′ north or south
astronomical polar night - meaning a day when sun's altitude remains below -18° entire day (there is no astronomical twilight at solar noon, only night), occurring poleward from 84°34′ north or south

These names were changed on Polar night article, and I wnat to know whether these named I listed are in use in any scientific papers, or in common language. (And I posted that question here and not in language desk because I think that this is not related to language very tightly.) --40bus (talk) 18:56, 16 December 2024 (UTC)

Some definitions at The Polar Night (1996) from the Aurora Research Institute. Alansplodge (talk) 22:55, 16 December 2024 (UTC)

These seem to be generalizable as: X polar night is a period, lasting not less than 24 hours, during which the sun remains below the horizon and there is no X twilight. The specific definitions depend then on the specific definitions of civil/nautical/astronomical twilight. These can be defined with a subjective observational standard or with an (originally experimentally determined) objective standard. --Lambiam 10:36, 17 December 2024 (UTC)

FWIW, I as a former amateur astronomer have never previously thought about the question of Polar twilight and night nomenclatures, but immediately and completely understood what the (previously unencountered) terms used in the query must mean without having to read the attached descriptions. {The poster formerly known as 87.81.230.195} 94.1.223.204 (talk) 16:34, 17 December 2024 (UTC)

December 17

differential equations with complex coefficients

In an intro ODE class one basically studies the equation ${\dot {x}}=Ax$ where x is a real vector and A is a real matrix. A typically has complex eigenvalues, giving a periodic or oscillating solution to the equation. That is very important in physics, which has various sorts of harmonic oscillators everywhere. If A and x are complex instead of real, mathematically the ODE theory works out about the same way. I don't know what happens with PDE's since I haven't really studied them.

My question is whether the complex case is important in physics the way the real case is. Can one arrive at it through straightforward coordinate transformations? Do the complex eigenvalues "output" from one equation find their way into the "input" of some other equation? Does the distance metric matter? I.e. in math and old-fashioned physics we use the Euclidean metric, but in realtivity one uses the Minkowski metric, so I'm wondering if that leads to complex numbers. This is all motivated partly by wondering where all the complex numbers in quantum mechanics come from. Thanks. 2601:644:8581:75B0:0:0:0:DA2D (talk) 22:54, 17 December 2024 (UTC)

Perhaps I don't understand what you are getting at but simple harmonic motion is xdot=j*w*x where w is angular frequency and j is i Greglocock (talk) 00:35, 18 December 2024 (UTC)

If PDEs count, the Schrödinger equation and the Dirac equation are examples of differential equations in the complex domain. A linear differential equation of the form

{\dot {x}}=Ax

on the complex vector space

\mathbb {C} ^{n}

can be turned into one on the real vector space

\mathbb {R} ^{2n}

. For a very simple example, using

n=1,

the equation

{\begin{bmatrix}{\dot {z}}\end{bmatrix}}={\begin{bmatrix}i\end{bmatrix}}{\begin{bmatrix}z\end{bmatrix}}

can be replaced by

{\begin{bmatrix}{\dot {x}}\\{\dot {y}}\end{bmatrix}}={\begin{bmatrix}0&-1\\1&0\end{bmatrix}}{\begin{bmatrix}x\\y\end{bmatrix}}.

--Lambiam 01:11, 18 December 2024 (UTC)

Shouldn't this be at the Math Desk? It almost seems like the IP could be trolling, given the same question just above. Abductive (reasoning) 14:49, 18 December 2024 (UTC)

The question whether the complex case is important in physics the way the real case is, is not a maths issue. IMO the Science section is the best choice. I do not see another post that asks the same or even a related question. --Lambiam 21:51, 18 December 2024 (UTC)

Just as above, I await a non-mathematical answer to this question. Abductive (reasoning) 07:01, 19 December 2024 (UTC)

Thanks all. Greglocock, your SHO example is 1-dimensional but of course you can have a periodic oscillator (such as a planetary orbit) in any orientation in space, you can have damped or forced harmonic oscillators, etc. Those are all described by the same matrix equation. The periodic case means that the matrix eigenvalues are purely imaginary. The damped and forced cases are where there is a real part that is negative or positive respectively. Abductive, of course plenty of science questions (say about how to calculate an electron's trajectory using Maxwell's equations) will have mathematical answers, and the science desk is clearly still the right place for them, as they are things you would study in science class rather than math class. Lambiam, thanks, yes, PDE's are fine, and of course quantum mechanics uses complex PDE's. What I was hoping to see was a situation where you start out with real-valued DEs in some complicated system, and then through some coupling or something, you end up with complex-valued DEs due to real matrices having complex eigenvalues. Also I think the Minkowski metric can be treated like the Euclidean one where the time coordinate is imaginary. But I don't know how this really works, and Misplaced Pages's articles about such topics always make me first want to go learn more math (Lie algebras in this case). Maybe someday. 2601:644:8581:75B0:0:0:0:DA2D (talk) 07:25, 19 December 2024 (UTC)

December 18

Why don't all mast radiators have top hats?

Our mast radiator article describes a device called a "top hat" which increases the range for mast radiators that can't be built tall enough.

So, why would you bother building a mast radiator without a top hat? Couldn't you just build it shorter with the top hat, and save steel? Marnanel (talk) 15:00, 18 December 2024 (UTC)

The main source cited in our article states, "Top loading is less desirable than increased tower height but is useful where towers must be electrically short due to either extremely low carrier frequencies or to aeronautical limitations. Top loading increases the base resistance and lowers the capacitive base reactance, thus reducing the Q and improving the bandwidth of towers less than 90° high." If "reducing the Q" is an undesirable effect, this is a trade-off design issue in which height seems to be favoured if circumstances permit. --Lambiam 21:41, 18 December 2024 (UTC)

Name of our solar system

Is our star system officially called "Sol", or is that just something that came from science fiction and then became ubiquitous? 146.90.140.99 (talk) 22:06, 18 December 2024 (UTC)

It's called the Solar System, and its star is called Sol, from Latin via French. Hence terms like "solstice", which means "sun stands still" in its apparent annual "sine wave" shaped path through the sky. ←Baseball Bugs carrots→ 23:31, 18 December 2024 (UTC)

Via French? According to the OED, it came direct from Latin. --Lambiam 11:45, 19 December 2024 (UTC)}}

Old French plus Latin. ←Baseball Bugs carrots→ 14:25, 19 December 2024 (UTC)

Also in Old French, the word meaning "sun" was soleil. --Lambiam 23:42, 19 December 2024 (UTC)

Let's say to that claim. The star is indeed called Sol if you're speaking Latin, but in English it's the Sun (or sun). Of course words like "solar" and "solstice" derive from the Latin name, but using "Sol" to mean "the Sun" does seem to be something from science fiction. --142.112.149.206 (talk) 06:04, 19 December 2024 (UTC)

"Sol" is occasionally used to mean the Sun by astronomers. I feel like it is used in contexts where it is necessary to distinguish our experience with the Sun here on Earth, such as sunsets, from more "sterile" aspects of the Sun one might experience off the Earth. Abductive (reasoning) 08:56, 19 December 2024 (UTC)

Being an astronomer myself, I don't think I've ever heard anyone use "Sol" outside of a science fiction context. --Wrongfilter (talk) 09:06, 19 December 2024 (UTC)

Scientific articles that use the term Sol; Development of the HeliosX mission analysis code for advanced ICF space propulsion and Swarming Proxima Centauri: Optical Communication Over Interstellar Distances. These are rather speculative but as I mentioned, the usage is for off-planet situations. Abductive (reasoning) 13:05, 19 December 2024 (UTC)

Using Sol, Terra and Luna to refer to the Sun, Earth and Moon only happens if you write your entire article in Latin and in science fiction, not in regular science articles. They are capitalised though. Just as people write about a galaxy (one of many) or the Galaxy (the Milky Way Galaxy, that's our galaxy). The Solar System is also capitalised. PiusImpavidus (talk) 10:38, 19 December 2024 (UTC)

The article says "Sol" is the "personification" of the sun. Google Image the term "old Sol" and you'll see plenty of images of the sun with a face, not just Sci-Fi stuff. And "Luna" is obviously the basis for a number of words not connected with Sci-Fi. Lunar orbit, lunar module, etc. And the term "terra firma" has often been used in everyday usage. ←Baseball Bugs carrots→ 11:34, 19 December 2024 (UTC)

And yet, if you ask 1,000 people "What's that big yellow thing up in the sky called?", you'll get 1,000 "the Sun"s and zero "Sol"s. Yes, in specialised contexts, Sol is used; but that doesn't justify saying our solar system's star "is called Sol" without any qualification, as if that were the normal, default term. It's not. -- Jack of Oz 12:16, 19 December 2024 (UTC)

And after you've gotten that response, ask them why it isn't the "Sunner System". And why a sun room attached to a house isn't called a "sunarium". And why those energy-gathering plates on some roofs are not called "sunner panels". ←Baseball Bugs carrots→ 14:22, 19 December 2024 (UTC)

What does that have to do with anything? The question was 'Is our star system officially called "Sol"?' (my emphasis). The answer is it is not. And that does not preclude other terms being derived from Latin sol (or, often enough, from Greek helios), nobody denies that, it is irrelevant to the question. --Wrongfilter (talk) 14:52, 19 December 2024 (UTC)

The problem is that the OP's question contains false premises. One is the question of what the "official" name is. There is no "official" name. It's the "conventional" name. And the second part, claiming that "Sol" comes from Sci-fi, is demonstrably false. ←Baseball Bugs carrots→ 15:05, 19 December 2024 (UTC)

Then demonstrate (that the usage of "Sol" as a name for the Sun, in English, not its use to derive adjectives, originated outside of SF), with references. The original question does not even include any premises, with maybe the exception of "ubiquitous". --Wrongfilter (talk) 15:18, 19 December 2024 (UTC)

"Is our star system officially called "Sol" , or is that just something that came from science fiction and then became ubiquitous? ". And the wording of your own question, just above, does not make sense. ←Baseball Bugs carrots→ 15:24, 19 December 2024 (UTC)

Looking at Newspapers.com (pay site), I'm seeing colloquial references to "old Sol" (meaning the sun) as far back as the 1820s. No hint of sci-fi derivation. ←Baseball Bugs carrots→ 15:32, 19 December 2024 (UTC)

Great! Well done. --Wrongfilter (talk) 15:41, 19 December 2024 (UTC)

Feel free to box up this section. ←Baseball Bugs carrots→ 15:52, 19 December 2024 (UTC)

The 1933 OED entry for Sol, linked to above, gives several pre-SF uses, the earliest from 1450. --Lambiam 23:48, 19 December 2024 (UTC)

Yes, of course, but that's not surprising, is it? 15th century humanists, astrologers and pre-Victorian poets liked to sprinkle their texts with Latin words. But I don't think this is what the question is about. It's a matter of context, but it should be up to OP to clarify that. --Wrongfilter (talk) 08:48, 20 December 2024 (UTC)

It's not surprising, but the discussion was not whether the use of Sol in English texts is surprising, but whether it originated outside of SF. --Lambiam 10:52, 20 December 2024 (UTC)

In my view, the question has a clear scifi bent, and that particular usage ("Where shall we go for our vacation? Alpha Centauri or Sol?") does not originate in the 15th century. The word is much older, of course it is, but the usage is not. In the 15th century people didn't even know that the Sun is just an ordinary star and could do with a particular name to distinguish it from the others. The connotations of sol were vastly different from what they are today and from what is implied in OP's question. Incidentally, the IAU doesn't even define a name , although they recommend using capitalised "Sun". Certainly no "Sol" anywhere. --Wrongfilter (talk) 12:04, 20 December 2024 (UTC)

Does that make it a Sol-ecism? Clarityfiend (talk) 12:19, 19 December 2024 (UTC)

More like a Sol-ips-ism. Meaning a factory where suns are made. From Sol = sun, and ipso = facto. Thus endeth the entymogology lesson for today. Go in peace to love and serve whomsoever. -- Jack of Oz 19:37, 19 December 2024 (UTC)

Mountains

Why there are no mountains on Earth with a height above 10,000 m? As the death zone is about at 8,000 m, and above 19,000 m, there is an Armstrong limit, where water boils at normal human body temperature, it is good that there are no more mountains higher than 8,000 km than just 14, but if there were hundreds of mountains above 9,000 m, then these were bad to climb. If there were different limits for death zone and Armstrong limit, would then there be possible to have higher mountains? I have just thought that, it is not a homework? --40bus (talk) 22:29, 18 December 2024 (UTC)

There are mountains elsewhere in the solar system that are over 20km high. Given that some of those are on airless worlds, I don't think the air pressure has any bearing on it. 146.90.140.99 (talk) 22:57, 18 December 2024 (UTC)

Multiple sources from web searching suggest the theoretical maximum height for mountains on Earth is around 15,000 m – the limiting factor is Isostasy; the higher (therefore more voluminous) a mountain is, the more its weight causes the crust beneath it to sink. The actual heights of mountains are a trade-off between how fast tectonic movements can raise them versus isostatic sinking and how quickly they are eroded, and tectonic movements do not last for ever. See also Orogeny. {The poster formerly known as 87.81.230.195} 94.1.223.204 (talk) 00:25, 19 December 2024 (UTC)

And erosion goes faster as the mountain gets higher, in particular when it's high enough to support glaciers – one reason why mountains can get higher on an airless world. Now it gets interesting for a mountain high enough to reach into the stratosphere, as it would be too dry to have anything but bare rock. I suppose it would locally raise the tropopause, preventing that. PiusImpavidus (talk) 11:13, 19 December 2024 (UTC)

December 19

Does human DNA become weaker with each generation?

As with photocopying something over and over, the text becomes less clear each time.

Does human DNA become weaker with each generation? HarryOrange (talk) 21:22, 19 December 2024 (UTC)

Sure, DNA replication is not perfect, although proofreading reduces the error rate to about 1 mistake per 10 nucleotides (see our article on DNA Replication). But that is per generation of cells, not of the whole organisms. Many mutations will be neutral in effect (because much of our DNA is redundant), some will be deleterious, and a few might be advantageous. It is the process of natural selection that hinders the spread of deleterious mutations: sometimes this aspect is called purifying selection. One thus usually expects a stable mutation–selection balance over time rather than that "DNA becomes weaker with each generation". Medical science is reducing the selection pressure against some mutations, which consequently may become more common. One of the problems for asexual organisms is referred to as Muller's ratchet; assuming that reverse mutations are rare, each generation has at least the mutational load of its predecessor. In contrast, in sexual organisms genetic recombination generates the variation that, combined with selection, can repair the situation. Sexual organisms consequently have a lighter genetic load. JMCHutchinson (talk) 22:42, 19 December 2024 (UTC)

So purifying selection won't work properly in case of Inbreeding ? HarryOrange (talk) 23:16, 19 December 2024 (UTC)

The larger the degree of inbreeding, the larger the chance that deleterious traits are expressed. But this very expression of traits leading to decreased biological fitness of their bearers is what actually enables purifying selection in the longer term. --Lambiam 23:36, 19 December 2024 (UTC)

@Lambiam so DNA repair won't stop these deleterious traits to get expressed? HarryOrange (talk) 14:11, 20 December 2024 (UTC)

No, this is not an issue of damage to the DNA. The genes involved are faithfully reproduced and passed on from generation to generation. --Lambiam 15:53, 20 December 2024 (UTC)

Or stronger e.g. "...we found that genes specifically duplicated in the Greenland shark form a functionally connected network enriched for DNA repair function", and those guys live for centuries and have much more DNA than us. Sean.hoyland (talk) 15:21, 20 December 2024 (UTC)

@Lambiam If not due to DNA damage, why do babies from inbreeding appear like DNA-damaged species? HarryOrange (talk) 17:29, 20 December 2024 (UTC)

Inbred offspring of species that normally outcross may show abnormalities because they are more likely than outcrossed offspring to be homozygous for recessive alleles that are deleterious. In individuals that are heterozygous at these loci, the recessive alleles will not be expressed (because the other wild-type dominant allele is sufficient to do their job adequately). See our article on inbreeding depression. JMCHutchinson (talk) 19:26, 20 December 2024 (UTC)

Larvae going south

In a novel I've just finished (The Chemistry of Death by Simon Beckett) he writes:

leave the body in an orderly fashion, following each other in a neat procession that always heads south. South-east or south-west sometimes, but never north. No-one knows why.

The author has done considerable international research on the science of forensic identification of decayed bodies and I assume his details can be trusted.

I've looked online for any verification of this surprising statement, but found only this, which seems to debunk it.

Is there any truth to this? -- Jack of Oz 23:38, 19 December 2024 (UTC)

Can't speak to its truth, but . . .

Does Beckett state this in his own auctorial voice (i.e. as an omniscient narrator)? If so, he might be genuinely mistaken.
The book was published nearly 20 years ago, what was the accepted wisdom then?
What specific species (if any) is the book describing? – your linked Quora discussion refers only to "maggots" (which can be of numerous species and are a kind of larva, but there are many others, including for example Processionary caterpillars).
Alternatively, if the statement is made by a character in the book, is that character meant to be infallible, or is he portrayed as less than omniscient, or an 'unreliable narrator'?

Regarding the statement, in the Northern hemisphere the arc of South-east to South-west is predominently where the Sun is found well above the horizon, the North never, so the larvae involved might simply be seeking maximum warmth or light. {The poster formerly known as 87.81.230.195} 94.1.223.204 (talk) 02:18, 20 December 2024 (UTC)

This appears in the very first paragraph of Chapter I, which starts out:

A human body starts to decompose four minutes after death. Once the encapsulation of life, it now undergoes its final metamorphoses. It begins to digest itself. Cells dissolve from the inside out. Tissue turns to liquid, then to gas. No longer animate, the body becomes an immovable feast for other organisms. Bacteria first, then insects. Flies. Eggs are laid, then hatched. The larvae feed on the nutrient-rich broth, and then migrate. They leave the body in an orderly fashion ... (then the quote above completes the paragraph).

It's not until para 2 that he starts talking about any human characters, and not until para 4 that he invokes the first person.

That's as much as I know. But I find it hard to believe he'd just make up a detail and put it in such a prominent place if it could so easily be debunked if it were not true. -- Jack of Oz 02:39, 20 December 2024 (UTC)

I wonder how they would measure the migratory path of maggots within a sealed coffin. ←Baseball Bugs carrots→ 02:51, 20 December 2024 (UTC)

The context of the novel is about finding decaying corpses that have been dumped in a forest. No coffins involved. -- Jack of Oz 06:08, 20 December 2024 (UTC)

Baseball Bugs, see also body farm research facilities. Alansplodge (talk) 13:44, 20 December 2024 (UTC)

Could it be that the larvae are setting off in search of another corpse? The prevailing wind in the UK is from the south-west, so by heading into the wind they won't be distracted by the frangrance of the one they've just left. Shantavira| 09:30, 20 December 2024 (UTC)

If you can, have a look at 'Heinrich, Bernd. “Coordinated Mass Movements of Blow Fly Larvae (Diptera: Calliphoridae).” Northeastern Naturalist, vol. 20, no. 4, 2013, pp. N23–27. JSTOR, http://www.jstor.org/stable/43288173.' Here are some extracts

On the fourth day, after a cooling night with dew on the grass, a stream of tens of thousands of larvae exited from beneath the carcass within 1 h after sunrise, and proceeded in a single 1-2-cm-wide column directly toward the rising sun...
However, in this case, the larvae left at night, within 1 h after a cloudburst (at 21 :00 hours). But, unlike before, this nocturnal larval exodus in the rain was diffuse; thousands of larvae spread out in virtually all directions over an 8 m2area. Apparently, the sudden moisture had cued and facilitated the mass exodus, but the absence of sun had prevented a unidirectional, en masse movement.
However, on the following morning as the sun was starting to illuminate the carcass on the dewy grass, masses of larvae gathered at the east end of the carcass at 07:00 hours. In one half hour later, they started streaming in a column directly (within one degree) toward the rising sun, and the carcass was then nearly vacated.

It goes on. Maggot migration appears to be a bit more complicated than the novel suggests. Sean.hoyland (talk) 09:39, 20 December 2024 (UTC) I suppose you could try to address it from the other direction and look at the technology your average maggot has access to in terms of light detection, heat detection, olfactory systems, orientation in magnetic fields (like many arthropods) etc. They presumably have quite a lot of tools. Sean.hoyland (talk) 10:13, 20 December 2024 (UTC)

If orderly migrating maggots tend to move towards the sun, they should display a northward tendency in Oztralia. --Lambiam 10:31, 20 December 2024 (UTC)

Maybe, but the novel is set in England.

I must say, as soon as I read the quoted para for the first time, my immediate thought was that it might have something to do with the magnetic field of the earth. -- Jack of Oz 10:42, 20 December 2024 (UTC)

Prime suspect might be the Bolwig organ, the photoreceptor cluster many fly larvae have. Sean.hoyland (talk) 10:49, 20 December 2024 (UTC)

Obviously, Jack, you need to create a corpse, place it in a nearby forest, and carefully observe which way the maggots go. For Science! And Literary Criticism! {The poster formerly known as 87.81.230.195} 94.1.223.204 (talk) 21:01, 20 December 2024 (UTC)

December 20

Winter solstice and time of sunrise?

How is it that despite December 21st supposedly being the shortest day of the year, sunrise here happens later and later until December 26 and only on January 05 starts to turn around to occur earlier and earlier. On December 25 it takes place at about 08:44, between December 26 and January 04 it takes place at about 08:45, and on January 05 it takes place again at about 08:44. (Google rounds out the seconds). Is it Google's fault? Is it everywhere the same? Confused in Brussels, Belgium. 178.51.16.158 (talk) 12:06, 20 December 2024 (UTC)

The pertinent article is Analemma, start with the section Earliest and latest sunrise and sunset. The details are not that simple to understand, but it's basically due to the ellipticity of Earth's orbit and its axial tilt. --Wrongfilter (talk) 12:22, 20 December 2024 (UTC)

Also note that sunset begins to be later on 22 December so that the time between sunrise and sunset is a few seconds longer than on 21 December (3 seconds longer on 22/12/24 in Brussels according to this). Alansplodge (talk) 13:33, 20 December 2024 (UTC)

Also see Equation of time#Major components. The obliquity of the ecliptic (that is, the Earth's axial tilt) is the main component and hardest to understand. But the idea is that the time when the Sun is exactly south (that is, the true noon) moves some minutes back and forth throughout the year and it moves quite rapidly to later times in late December. PiusImpavidus (talk) 19:05, 20 December 2024 (UTC)

Three unit questions

Why territorial waters are defined by nautical miles instead of kilometers?
Why GDP is usually measured in US dollars rather than euros? Euro would be better because it is not tied into any country.
Are there any laws in United States that are defined by metric units?

--40bus (talk) 23:30, 20 December 2024 (UTC)

There were nautical miles in use before there were kilometers.
There were US dollars in use before there were Euros.
Yes.

The questions all reduce to Why can't millions of people make a change of historically widely accepted units that continue to serve their purpose, and convert to different units that would have no substantive difference, because someone has an opinion. Philvoids (talk) 00:52, 21 December 2024 (UTC)

Do any people use metric units in marine and air navigation like "The ship is 10 kilometers from the port", "The plane is 10 kilometers from the destination? And is there any European country with metric flight levels? --40bus (talk) 07:22, 21 December 2024 (UTC)

Inland shipping (rivers, canals and lakes) in Europe (except the UK) is fully metric. Ships going for example Tilbury – Duisburg may have to switch units along the way. Gliders and ultralight aircraft in Europe often use metric instruments and airport dimensions are also metric (including runway length). Countries are free to define their territorial waters in whatever way they deem fit, so with nautical miles having no legal status in a fully metric country, they may define their territorial waters as extending 22224 metres. PiusImpavidus (talk) 11:23, 21 December 2024 (UTC)

Our nautical mile article says: "In 1929 the international nautical mile was defined by the First International Extraordinary Hydrographic Conference in Monaco as exactly 1,852 metres (which is 6,076.12 ft). The United States did not adopt the international nautical mile until 1954. Britain adopted it in 1970..."

As the US customary units are actually defined in terms that relate them to metric units, any US law based on measurements is technically defined by metric units.--User:Khajidha (talk) (contributions) 01:55, 21 December 2024 (UTC)

The US dollar has been the world's dominant reserve currency for about 75 years. As for the metric system in the US, it is standard in scientific, medical, electronics, auto manufacturing and other highly technical industries. By law, all packaged foods and beverages have metric quantities as well as customary quantities. See Metrication in the United States. Cullen328 (talk) 02:28, 21 December 2024 (UTC)

The Wikipaedia article on the Nautical Mile talks about how the term originated, it was originally defined in terms of latitude not as a number of meters 114.75.48.128 (talk) 10:03, 24 December 2024 (UTC)

The euro is tied to multiple specific countries is it not? If you use euros you're just changing from one "dependency" to a "dependency" on the eurozone countries. A statement of the problem or problems intended to be addressed would be useful. Currency values are interconvertible in any case. Economics does sometimes use the "international dollar" for certain things, which is intended to adjust for differences in purchasing power between countries and over time. But since it's not an actual "real" currency it's not something one can easily "visualize" in their heads, which is likely why it's not used more. --Slowking Man (talk) 05:41, 26 December 2024 (UTC)

December 24

Unknown species of insect

Am I correct in inferring that this guy is an oriental beetle? I was off-put by the green head at first, but the antennae seem to match. Jay Cubby 03:00, 24 December 2024 (UTC)

(reference: https://www.genesdigest.com/macro/image.php?imageid=168&apage=0&ipage=1)

~~It looks like one of the invasive Japanese beetles that happens to like my blackberries in the summer.~~ Modocc (talk) 13:11, 24 December 2024 (UTC)

I would say not necessarily a Japanese beetle, but almost certainly one of the other Scarab beetles, though with 35,000 species that doesn't help a lot. Looking at the infobox illustration in that article, 16. & 17., "Anisoplia segetum" looks very similar, but evidently we either don't have an article or (if our Anisoplia article is a complete list) it's been renamed. {The poster formerly known as 87.81.230.195} 94.1.223.204 (talk) 14:18, 24 December 2024 (UTC)

Yes, it's not the Japanese beetle for this beetle appears to lack its white-dotted fringe although its condition is deteriorated. Its shape is also more or less more slender; and not as round. Modocc (talk) 15:02, 24 December 2024 (UTC)

Perhaps it is the shining leaf chafer Strigoderma pimalis. Shown here. Modocc (talk) 16:09, 24 December 2024 (UTC)

That looks like easily the best match I've seen so far, and likely correct. {The poster formerly known as 87.81.230.195} 94.1.223.204 (talk) 17:09, 24 December 2024 (UTC)

December 25

Mass of oscillating neutrino

From the conservation of energy and momentum it follows that a particle that is not subject to external forces must have constancy of mass.

If I am right, this means that the mass of the neutrino cannot change during the neutrino oscillation, although its flavoring may. Is this written down somewhere? Thank you. Hevesli (talk) 19:24, 25 December 2024 (UTC)

Any (flavored) neutrino that is really observed is a superposition of two or three mass eigenstates. This is actually the cause of neutrino oscillations. So, the answer to your question is complicated. Ruslik_Zero 19:40, 25 December 2024 (UTC)

Important note: particle physicists today generally only ever use "mass" to mean "invariant mass" and never anything else: . Like the term says, invariant mass is well, invariant, it never changes ever, no matter what "external forces" may or may not be involved. Being proper particle-icans and following the standard practice in the field, then, the three neutrino masses are constant values. ..."Wait, three?" Yeah sure, turns out neutrinos come in three "flavors" but each flavor is a mixture of the three possible mass "states". As mentioned, due to Quantum Weirdness we aren't able to get these different states "alone by themselves" to measure each by itself, so we only know the differences of the squares of the masses. Yeah welcome to quantum mechanics.

Richard Feynman: "Quantum mechanics describes nature as absurd from the point of view of common sense. And yet it fully agrees with experiment. So I hope you can accept nature as She is – absurd." --Slowking Man (talk) 06:06, 26 December 2024 (UTC)

The equation

E^{2}=(pc)^{2}+\left(m_{0}c^{2}\right)^{2}

uses invariant mass m₀ which is constant if E and p are constant. The traveling neutrino has a varying mass mixture of different flavors with different masses. If a mixture of different masses changes, you would expect the resulting mass to change with it. But somehow this does not happen as the neutrino mass mixture changes. These mixture changes cannot be any changes. The changes must be such that the resulting mass of the traveling neutrino remains constant. My question is whether this is described somewhere. Hevesli (talk) 11:16, 26 December 2024 (UTC)

I freely confess I'm uncertain exactly what's being "asked for" or "gotten at" here. Have you looked at the neutrino oscillation article? From it: That is, the three neutrino states that interact with the charged leptons in weak interactions are each a different superposition of the three (propagating) neutrino states of definite mass. Neutrinos are emitted and absorbed in weak processes in flavor eigenstates but travel as mass eigenstates.

What is it that we're "doing" with the energy–momentum relation here? For the neutrino, we don't have a single value of "mass" to plug in for

m_{0}

, because we can't "see" the individual mass eigenstates, only some linear combination of them. What you want for describing neutrino interactions is quantum field theory, which is special relativity + QM. (Remember, relativity is a "classical" theory, which presumes everything always has single well-defined values of everything. Which isn't true in quantum-world.) --Slowking Man (talk) 18:41, 26 December 2024 (UTC)

Not all potential evolutions of a linear combination of unequal values produce constant results. Constancy can only be guaranteed by a constraint on the evolutions. Does the fact that this constraint is satisfied in the case of neutrino oscillation follow from the mathematical formulation of the Standard Model, or does this formulation allow evolutions of the mass mixture for which the combination is not constant? If the unequal values are unknown, I have no idea of how such a constraint might be formulated. I think the OP is asking whether this constraint is described somewhere. --Lambiam 00:51, 27 December 2024 (UTC)

December 27

Low-intensity exercise

If you exercise at a low intensity for an extended period of time, does the runner's high still occur if you do it for long enough? Or does it only occur above a certain threshold intensity of exercise? 2601:646:8082:BA0:CDFF:17F5:371:402F (talk) 20:13, 27 December 2024 (UTC)

Hows about you try it and report back? :) ←Baseball Bugs carrots→ 21:31, 27 December 2024 (UTC)

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