Wikipedia:Reference desk/Archives/Science/2014 November 22

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November 22

Dwarf Reproduction

This is a serious question caused by my random curiosity. When Dwarves/Little People have children, is the child a Dwarf/LP themselves? Is it always the case, or does it vary?72.224.177.187 (talk) 00:05, 22 November 2014 (UTC)SMV207

If two dwarfs (assuming you mean achondroplastic) mate, two thirds of their children on average will also be dwarfs, and one third will be of average stature. This is because the gene causing dwarfism is dominant, and a lethal allele when homozygous (i.e, present in two copies, one from each parent).

Living dwarfs carry only one dwarf allele and one wild-type allele. (If they had two, they'd have died during gestation.) So, according to the Punnett Square diagram of Mendelian genetics, 1/4 of conceptions will have two dwarf genes and die during gestation, 2/4's will have one wild-type (her, non-dwarf) and one dwarf gene, and 1/4 will have two wilde-type genes and average height. This website has some helpful visualizations. μηδείς (talk) 01:38, 22 November 2014 (UTC)

This dwarf answered that question on Cracked a couple of days ago. Only one in his family, normal wife, normal kids, normal parents. Touched on the hereditary dangers on the next page, thinks we'd all be better off without dwarves in the future. InedibleHulk (talk) 02:40, 22 November 2014 (UTC)

Personally, I feel that my reaction to eugenics is conditioned on the age of an allele. If a particular form of a gene arose sometime within the past thousand years, well, like Cronus, humanity should feel a right to devour its creations. Such a gene is untested and often unsatisfactory for human beings to have. But if the allele dates back a million years, having survived countless vicissitudes of fate throughout all the development of the human condition as we know it, then for our culture narrow-mindedly to say now that we have no place for it is unreasonable. It is redesigning the shape of the child to fit the shape of the classroom chair, when what we should be doing is designing the classroom seat to be satisfactory to a full range of children available. When we give into a temptation to trim away parts of the human genetic diversity to fit some current circumstance, we drain the overall gene pool and sap, long term, the ability of human beings to adapt and survive. So the question then with dwarfism is whether we would be using eugenics to wipe out longstanding human diversity or simply fixing an inborn genetic error. Where achondroplasia is concerned, I'm seeing figures that (very surprisingly to me) fully 90% of the alleles are sporadic - not going back even one generation. [1] It is not guaranteed that 99% of them did not affect a grandparent, but that seems a fair guess, at least. That said, in more general terms short stature is a very common polygenic condition, and most of human history features people shorter than those of modern times; many of those alleles are likely to be long-term survivors of the Darwinian struggle. Wnt (talk) 07:00, 22 November 2014 (UTC)

Yeah, I lean toward playing the cards we're dealt, to build what society we can. But for what it's worth, that guy's opinion came more from the health problems dwarves are prone to than the social handicaps. He notes "thanks to technology and human ingenuity, just about every facet of work and life can be successfully performed by little people nowadays." Internal biology is the tougher hill, whether we want to climb it or bulldoze it. InedibleHulk (talk) 16:54, 22 November 2014 (UTC)

Anyway, the relevance here is that firstly, it is not going to be possible to stop sporadic mutations by genetic engineering the parents. Either you check each and every zygote for achondroplasia (for example it is possible to remove one of the 8 cells from the 8-celled embryo and test it, though that gives me heebie jeebies) or you abort embryos with the condition at a later stage (which many peopel find morally unacceptable) or you live with the fact that mutations happ3n. And also, it follows logically that, for whatever reason, most of those affected don't actually pass along the condition they have to offspring. Wnt (talk) 07:00, 22 November 2014 (UTC)

Holographic rings

I remember seeing a metal ring, laser-inscribed with a hologram. Where can I find images of this? Plasmic Physics (talk) 07:33, 22 November 2014 (UTC)

Do alcoholics have a greater genetic tendency to find alcohol pleasing to taste?

I don't like the taste of alcohol. Whether it's beer or wine, they all taste funny and feel burning on my tongue, along with a very unpleasant, bitter taste. I notice that some people are moderate drinkers and some people exhibit alcoholism. I am wondering if alcoholics in particular have a greater genetic tendency to find alcohol pleasing. 71.79.234.132 (talk) 15:58, 22 November 2014 (UTC)

I don't think it's quite that simple. Alcoholism has to do with the effect the stuff has on an individual. ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:16, 22 November 2014 (UTC)

Sorry, I don't have an answer, but Acquired taste may be of use. Like you, I found the taste of wine and beer to be distinctly unpleasant, but sampling it a few times gradually brought me around. But my acceptance of the taste has had no real effect on the possibility of becoming alcoholic; addiction is a very different thing from enjoyment. Our article on Alcoholism lists a few causes; "flavour" doesn't seem to be among them. Matt Deres (talk) 16:20, 22 November 2014 (UTC)

Aye. See Cracked's first drinking myth here. I was a binge drinker for a decade or so, but for fun. For escaping stress, I've always preferred weed. InedibleHulk (talk) 18:16, 22 November 2014 (UTC)

(ec)Most people don't like alcohol when they first try it as it's an acquired taste. Many people who like alcoholic drinks started drinking something where the taste of the alcohol was masked by the sweetness of the drink and then, as they get used to that, moved onto more bitter drinks as their palate matured. Some just go straight into drinking bitter drinks, such as beer, though peer pressure and eventually learn to like them by habituation. Richerman (talk) 16:28, 22 November 2014 (UTC)

• No one finds the "taste" of ethanol itself a pleasing sensation, although they may like certain drinks, and associate the taste with pleasant aftereffects. There's belief that tolerance to certain effects of alcohol is genetic, and a factor in alcoholism. This source tangentially mentions the genetic component in tolerance to some side effects. See also: "East Asians and American Indians: Most individuals use a form of acetaldehyde dehydrogenase called ALD2 to metabolize the acetaldehyde which results from alcohol metabolism. However, many East Asians and American Indians produce a form of acetaldehyde dehydrogenase called ALD2*2 which is far less efficient at breaking down acetaldehyde than ALD2. ALD2*2 is only about 8% as efficient as ALD2 at metabolizing acetaldehyde." μηδείς (talk) 18:05, 22 November 2014 (UTC)

• on the "No one" bit. --Jayron32 18:16, 22 November 2014 (UTC)

I am not going to search for a source that says pure ethanol burns any more than I am going to look for a source that sugar is sweet. There may be an associate pleasure of anticipation of the effects, but no one would ever say, give me something that burns like pure alcohol but doesn't make me drunk or they'd be marketing it already. μηδείς (talk) 19:56, 22 November 2014 (UTC)

That's like claiming that a person can only like the flavor of cheese when baked in a dish, but would never choose to eat cheese on its own, or find the taste or sensation of cheese in isolation to be unpleasant. I do like the taste of ethanol in isolation; a slow sipping well-made vodka is divine, and some of the best tasting alcohol I've ever had was unflavored white lightning from JoCo's finest independent distillery family. I enjoy beer, I enjoy wine, I enjoy a good margarita, but I also like a sipping whiskey, a good chilled vodka, a fine tequila, and yes, even high-proof ethanol, the taste itself is pleasing to me. I'm not an alcoholic, but I do enjoy the taste of ethanol all on its own, absent its effects. I don't drink to excess because I dislike the feeling of being drunk, but I do drink for the flavor. --Jayron32 02:47, 23 November 2014 (UTC)

When I was at secondary school one of the chemistry teachers ran a still in the corner of the lab (purely for medicinal purposes, I'm sure). He invited a few of us to taste the product. It did "burn", but not unpleasantly. When I started going to pubs in my teens I very quickly gravitated to bitter rather than the much blander lagers favoured by many novice drinkers. DuncanHill (talk) 03:44, 23 November 2014 (UTC)

Without commenting on the specifics of whether anyone finds alcohol pleasing, I don't get the relevance of pure alcohol. Many people find some degree of chilli hotness enjoyable depending on learned enjoyment etc. There may be a minor component of pleasant aftereffects but I see no evidence it's the only or even main reason people come to enjoy it. Yet even among those who enjoy it a fair bit like many Malaysians, I don't belief many will want to try a Carolina Reaper except sometimes for experimentation or demonstration purposes. Since you mentioned sweetness, while a vast majority of people find it pleasurable t to some degree, clearly even among them there are a fair few who don't enjoy candy floss or something else which is basically pure sweetness for reasons beypnd health fears. Nil Einne (talk) 21:37, 22 November 2014 (UTC)

The question was about alcohol, not alcoholic beverages. Maybe safe to assume s/he meant those, but that would make the answer so much harder. Pretty much every kid likes schnapps, but not so many want some rye. InedibleHulk (talk) 22:21, 22 November 2014 (UTC)

Again, if people liked the taste of ethanol itself, as opposed to the taste of, say, a Guinness, people would be marketing alcohol flavored-X. μηδείς (talk) 00:36, 23 November 2014 (UTC)

"I don't like the taste of alcohol. Whether it's beer or wine, they all taste funny..." - that's about alcoholic beverages isn't it? Richerman (talk) 01:36, 23 November 2014 (UTC)

I suppose we could ask the IP to taste some unflavored vodka, and let us know if that has the same taste he dislikes in other beverages. But I think we'd be getting pretty silly to go that far, especially when you omitted the next phrase of the OP's: and feel burning on my tongue.... μηδείς (talk) 01:47, 23 November 2014 (UTC)

This is the science desk. A sample size of two proves nothing. There may be something else in both those drinks that cause the "burning". And "feel burning on my tongue" is obviously not a scientific statement HiLo48 (talk) 03:14, 23 November 2014 (UTC)

So what is this other conspiracy-theory substance, that may cause the burning, that you introduce without a shred of evidence, HiLo? Here's an interesting blog you find if you google "burning taste of alcohol". μηδείς (talk) 04:21, 23 November 2014 (UTC)

There are conflicting theories (probably) on whether the burn from Goldschläger comes from the ethanol, cinnamon or gold. Fireball Cinnamon Whisky isn't exactly soothing, either. But yeah, as far as we know, the OP didn't mix those in the beer and wine. InedibleHulk (talk) 23:26, 23 November 2014 (UTC)

What is a burning taste? Is the OP's burning taste the same as yours, or mine?HiLo48 (talk) 04:40, 23 November 2014 (UTC)

What is the appearance of red, or the taste of sweet, HiLo? And again, why are you allowed to posit some mystery substance causing some taste you doubt exists, while I need to provide a reference--even further, to prove-- that ethanol burns? To quote Aristotle, "to prove what is obvious by what is not is the mark of a man who is unable to distinguish what is self-evident from what is not. (This state of mind is clearly possible. A man blind from birth might reason about colours.) Presumably therefore such persons must be talking about words without any thought to correspond." μηδείς (talk) 18:30, 23 November 2014 (UTC)

Again I don't get the relevance of this diversion. The question wasn't whether the OP dislikes the taste of alcohol, but whether there's any support for your claim that no one (and not just the OP) likes the taste of alcohol. Since you seem to have ignored the points that have been made namely that just because people may not like the taste of pure alcohol, doesn't mean the alcohol may not be an important part of what makes the beverage taste good, and therefore it's easily possible, perhaps probable that people do like the taste of alcohol just as we know they do like the taste of chili hotness, sweetness or cheese without necessarily enjoying the taste of these in isolation; I can only assume you accept you made a mistake.

P.S. As for the suggestion someone would make something which would mimic the taste of alcohol, that would depend on several factors like the how easy it is relative to the possible reward. That in turn would depend on factors like the demand, just because some people enjoy the taste of alcohol doesn't mean there would be sufficient demand since it may be there are sufficient people for who the after effects are an important enough addition that the market would be small. And as for the possibilities, since I drink so little that I don't know enough about the taste of alcohol except that I find it bitter, I can't comment except to say evidence shows a lot of attempts to produce artificial tastes are only mildly successful. People may find them sufficient, or they may grow to enjoy them even though they don't mind that they are different. Of course it doesn't help that some people who may want this thing are probably the same people who go for the same "all natural nonsense".

Perhaps the final point is you seem to be assuming it hasn't been tried without evidence. Again, not something I'm particularly interested in but I know as I assume you do there are a lot alcohol free variants of common alcoholic beverages. From what I've seen, the alcohol-free part is often sold more as a "it won't have the effects" rather than "it doesn't taste like alcohol". In fact, a common complaint seems to be that they don't taste like the real thing. This probably at least partially relates to the fact that many of them are made different because fermentation is often an important part of how the original alcoholic variants are made, but it seems possible the lack of a real alcoholic taste is another factor. We also get in to the complexity I hinted in my first reply namely that "taste" can be a complicated mix of factors, and for alcohol, stuff like the evaporation may be a factor. There seems to be some discussion of that here [2] and here's someone who wants it [3] albeit not because they like the taste (this gives another market avenue [4]).

Perhaps most interesting is [5] who sell stuff like alcohol free vodka and whiskey. How close this sort of stuff comes I don't know, but they don't seem to advertise the lack of a burning sensation or alcohol taste, instead they do talk about a burning [6] or warming sensation. I'm not sure if these ones are real but there may also be [7] [8], the website for the Blue Zero and Black Zero seem dead and I can't be bothered looking for archives. There's also [9] [10] but that may have been a 1 time thing. (Of course [11] is a cautionary tale.) The lack of success of these attempts may suggest such demand for full hard liquor substitutes is small, which may suggest the number of people who truly enjoy the taste is small (or at least for many of those who do, the after effects are also an important component), but this still tells us little about how many people may enjoy the taste of alcohol in less extremes. It does suggest the number may not be zero, as you suggested it was.

Nil Einne (talk) 22:57, 23 November 2014 (UTC)

BTW, your source or at least the quote appears to oversimplify the frequency of ALD2*2 to the point of being misleading. As I mentioned in an old discussion with refs Wikipedia:Reference desk/Archives/Science/2013 December 8#Native North American genetics (another one I came across [12]), it's not clear that many native North Americans commonly have the same aldehyde dehydrogenase polymorphisms as East Asians. Note that the the polymorphism common among East Asians which results in alcohol flush reaction seems to have a protective effect against alcoholism (the suggested reasons namely that it increases the negative short term effects while decreasing the positive short term effects does make some sense), although as our ALDH2 article says, this doesn't mean cultural and other factors may not lead to increasing alcoholism (and they may also have some more negative long term effects from alcohol consumption and particularly alcoholism). As our Alcohol and Native Americans says, some native American populations have a problem with alcoholism. While there could be no genetic contributor and it could be those that do have such problems generally lack the protective polymorphism but many others don't (and as said, there could be reasons why they overcome the protective effect), it is IMO an immediate to look and see if there's actually evidence they do have the polymorphism. If people are still interested, perhaps a read and look of the links Aldehyde dehydrogenase and Alcohol dehydrogenase will also help. Nil Einne (talk) 23:37, 23 November 2014 (UTC)

I assume you've heard of crack, crystal meth, and e-cigs. If there were a market for ethanol-flavored items it would be filled, even if it were a deadly black-market substance. The only disagreement I see above is based on the unsupported notion that some burning sensation is caused in alcoholic drinks by an unnamed, unsourced mystery substance, and that the taste of ethanol is unknown. Both assertions are simply ludicrous. μηδείς (talk) 00:13, 25 November 2014 (UTC)

I found [13] which may interest the OP although I can't comment on the accuracy. It does remind me that Supertasters appear to be more likely to dislike the taste of certain alcoholic beverages, something which I've read before but didn't recall until now although I'm not sure if it's established alcohol is responsible. While it may seem in the opposite direction, this does ultimately mean there are some people (even if it's a majority) who may find the taste less unpleasant and so more pleasant. It also suggests TRPV1 may be involved. Nil Einne (talk) 23:02, 23 November 2014 (UTC)

I'm one who finds the taste of ethanol to be extremely bitter. Mixing in lots of sugar makes it tolerable, but by no means good tasting, to me. I've posed a similar Q here before, because it seemed odd to me that many people choose to drink alcoholic beverages, when not trying to get drunk. To me that would be like drinking motor oil. It might help to look at it from an evolutionary POV:

1) Originally, ethanol was purely a poison, like methanol, and animals which had an aversion to it would be more likely to survive and pass on those genes.

2) The development of ALDH and ALDH2 made it less of a poison, so it became reasonable to eat, say, fermented fruit, which might contain small quantities of alcohol. At this point it would be expected that the aversion to alcohol be reduced or even eliminated.

3) Later on, humans learned to distill ethanol, such that a lethal dose was again possible. At this point, the original aversion to alcohol may again be the most evolutionally advantageous.

Note that the ability to digest lactose into adulthood also developed as humans started herding livestock, but has not spread to the entire human population, so similar partial evolutionary changes regarding the metabolism and preference for ethanol on the same time scale also seems possible.

As for the relation to alcoholism, there may very well be people out there, perhaps even me, who would become alcoholics if they drank enough ethanol to get the addiction started, but never get there due to it's foul taste (to us). StuRat (talk) 15:05, 26 November 2014 (UTC)

Car park structure

http://www.movie-locations.com/movies/t/tomorrownever.html

In the first photo showing that car park, I see the column encased in concrete for durability, the primary beam but I'm not sure why the encasing gets slightly bigger at the joint with the column. And secondly, what is the stuff in between the primary beams? Why is it grooved? Is that prestressed concrete? Or is it just reinforced concrete slabs in between secondary beams? 82.132.247.134 (talk) 16:50, 22 November 2014 (UTC)

When you say "the encasing gets slightly bigger", are you talking about the green part? I suggest that that's simply a layer of some kind of plastic, used to label the sections of the parking lot in preference to painted markings that would need to be renewed over the years. Note that the column behind the front one, which has no green on it, seems to have perfectly straight edges as far as can be seen by enlarging that little picture.

Or, wait, do you mean where the bottom of the primary beams goes slightly diagonal? That'd be to create an arch shape, hopefully keeping the line of compressive force within the concrete. --65.94.50.4 (talk) 20:44, 22 November 2014 (UTC)

yes I do. That's a steel beam encased in concrete I think. But what's the lines going in between the primary beams? Is it prestressed concrete?

Is the Cascade storage system based on diffusion?

213.57.99.239 (talk) 17:59, 22 November 2014 (UTC)

Cascade storage system is our article is case someone is unfamiliar with the idea. DMacks (talk) 20:00, 22 November 2014 (UTC)

Does coating a boat in PTFE (or other hydrophoric substance) makes it more energy efficient?

--Senteni (talk) 18:27, 22 November 2014 (UTC)

One would think that a hydrophobic coating would help reduce drag. But at least one study showed that superhydrophobic coatings decreased drag in the laminar regime, but increased drag in the turbulent regime due to surface roughness effects. Most boats are large enough and move fast enough that most of the hull is in the turbulent regime (high Reynolds number), so such coatings wouldn't seem to help. --Mark viking (talk) 09:37, 23 November 2014 (UTC)

In general coating adds to the ship's displacement/mass and so it will unlikely produce more efficiency. BUT, as already pointed out by Mark viking turbulences are a key component of drag and todays technology has adapted concepts of microstructured surfaces copied from nature (for example shark skin) and is using these with great success for example in High-technology swimwear fabric. --Kharon (talk) 14:49, 23 November 2014 (UTC)

If you have a coating which reduces drag for laminar flow only, then perhaps it should only be applied to the leading edge of the bow, where laminar flow normally occurs even at high speeds. This would be particularly useful if it has the effect of extending the laminar flow region further away from the bow. StuRat (talk) 15:12, 26 November 2014 (UTC)

What does carry the signal in a wifi?

There should be a variation on the wave that can be captured. In radio broadcasting you either can vary the amplitude to obtain AM or the frequency to obtain FM. In a wlan, how is one message different from the other? How they put messages on these waves?--Senteni (talk) 18:37, 22 November 2014 (UTC)

The Wikipedia article Carrier signal discusses how one uses a specific frequency of light (usually in the radio waves or microwave region of the electromagnetic spectrum) to "carry" information wirelessly. Your wifi does not work any differently, fundementally, than the very first radios invented by Guglielmo Marconi and Nikola Tesla among others. The transmission of wifi (and cell phone, and satelite communications, etc.) of ALL of them works pretty much the same way, and the carrier signal article explains it. The only difference in various wireless technologies is in what sort of information gets encoded on the carrier wave, and how it is encoded and decoded at the transmission and receiver ends. Specific to wifi, the specific way that wifi signals are encoded, transmitted, and decoded is governed by the IEEE 802.11 standards. Wifi broadcasts in two specific parts of the radio spectrum; there's a band near 2.4 GHz, and another near 5.8 GHz, that wifi devices broadcast in. --Jayron32 18:46, 22 November 2014 (UTC)

Re: "frequency of light", I'd say "frequency of the electromagnetic spectrum" instead. StuRat (talk) 15:18, 26 November 2014 (UTC)

Apparently WiFi uses quadrature amplitude modulation. [14] AndyTheGrump (talk) 18:47, 22 November 2014 (UTC)

If you read our article on IEEE 802.11#Protocol, you'll see that the answer depends on the type of WiFi signal. Quadrature amplitude modulation and phase shift keying are the common theme for this family of digital communications. Nimur (talk) 18:58, 22 November 2014 (UTC)

Sunrise/sunset times not exactly correlated

I've seen a simple explanation of this phenomenon somewhere, but I can't remember where.

Around the solstices, why are the "turn-around" times for sunset and sunrise not on the same day? Here in Beaver Falls, Pennsylvania, we're going to have this year's earliest sunset at 4:54 PM, beginning on 2 December and continuing until 15 December, while our DST-adjusted latest sunrise for this winter will be 7:46 AM, beginning on 2 January and continuing until 7 January — and neither one is happening during the winter solstice. I would naturally assume that the earliest sunset and latest sunrise would occur together in a group of days "centered" on the solstice, so we'd have 7:46 sunrises and 4:54 sunsets from 19 December until 24 December. Why is this not the case? Nyttend (talk) 18:48, 22 November 2014 (UTC)

The path of the Earth around the sun is not symmetric, that's why the longest day does not fall on the same day as the earliest sun-rise or sun set. --Senteni (talk) 19:40, 22 November 2014 (UTC)

First, there's no direct correlation between days and the year. Days are actually 23h 56+m long, and the year is about 365 1/4 days long. Second, the solstices and equnoxes actually mark points in time that happen to fall on a certain day, not day-long periods. Third, local legal time varies, and the sun does not set or rise at the same moment over an entire time zone. Lastly, we do not adjust our clocks daily, moving official noon to match the exact time at which the sun is highest, so even if sunrise and sunset are theoretically equidistant from solar noon (the highest point) they are not equidistant from noon by the clock. All of this combines to make an actual expectation of a 6am sunrise and a 6pm sunset on the equinox a matter of approximation, not fact. μηδείς (talk) 19:51, 22 November 2014 (UTC)

I asked the same question in January 2013 - the answers are here. Richerman (talk) 19:57, 22 November 2014 (UTC)

In particular, note the answer by Dolphin, which nicely explains the two reasons, both related to the Earth's orbit being elliptical rather than circular. --65.94.50.4 (talk) 20:32, 22 November 2014 (UTC)

Medeis, you primarily address the equinox, not the solstice. After all, 6am sunrise/6pm sunset would require the absence of time zones and a sun that's just a point, not a disk. I'm not asking about lengths of days vs. length of nights, so as far as I can tell, you've misunderstood me. Nyttend (talk) 20:53, 22 November 2014 (UTC)

The same factors apply, solar days and noons do not correspond to days or noons by the clock, the solstices and equinoxes are points in time, that fall on a day, but do not correspond to the day they fall on, time zones are not lines, they have different times of sunset and sunrise at different places. Even if we had a perfectly circular orbit with a year evenly divisible by 4 into seasons of, say, exactly 90 days length, the earth is still a large sphere, moving around the sun at about 1.6 million miles a day.

Only that exact longitude which was under the sun at noon (in winter, furthest from the sun at midnight), not anywhere east or west of it would have the actual longest, shortest, or even day and night. None of the assumptions that would be necessary for your conditions in regard to the clock actually applies.

I'd love it if clocks were such that noon always occurred when the sun was highest and years were exactly divisible by four, but it wouldn't be conducive to business or government for every latitude to have its own separate noon. If I am misunderstanding you, maybe you could reword what you are asking? Or perhaps someone else will answer or has answered to your satisfaction. μηδείς (talk) 21:47, 22 November 2014 (UTC)

Senteni is correct that the path round the sun is not quite symmetric, but the asymmetry in sunrise and sunset is an artefact of the way we run our clocks. Sunrise and sunset are perfectly symmetric about local noon, but local noon is changing rapidly with respect to our clocks around the time of the equinoxes because of the Equation of time. By the way, Medeis' defintion of day does not correspond to mine. Dbfirs 22:11, 22 November 2014 (UTC)

You have basically just repeated what I said, calling it local noon instead of my "solar" versus "by the clock" noon. We had the day debate thing before, and I am not sure what your point is in pointing out your disagreement, since I didn't give any one of the various explicit definitions that might be meant by context. μηδείς (talk) 00:33, 23 November 2014 (UTC)

It's the change in the discrepancy between clock time and "sun" time that causes the asymmetry. No antagonism was intended: I was just taking the opportunity to link to the articles for anyone who wished to research further, and anyone who was puzzled by your "Days are actually 23h 56+m long" claim. Dbfirs 08:26, 23 November 2014 (UTC)

Medeis makes one clear error. A year is 365¼ mean solar days of 24h, or 366¼ sidereal days of 23h 56m. —Tamfang (talk) 08:34, 23 November 2014 (UTC)

Even assuming this 'clear error', which amounts to putting words in my mouth, and ignoring my use of "about" to avoid going into jargonistic detail, are you saying that my actual point was wrong, Tamfang? Or just scoring points clarifying? μηδείς (talk) 18:18, 23 November 2014 (UTC)

It's not a competition. Our aim here is to give the best and fullest answer to the OP's question, not to score points. You seemed to be answering a different question. Wnt's first link below is perhaps the best answer because it shows that the most rapid drift in local (sun) time compared to clock time occurs in December. Dbfirs 09:35, 24 November 2014 (UTC)

I agree that the point here is to approximate a spherical cow answer rather than pointing out the motes in our neighbour's eyes. μηδείς (talk) 00:08, 25 November 2014 (UTC)

• See analemma / equation of time. Wnt (talk) 13:54, 23 November 2014 (UTC)

In addition to elliptical orbit is the rotational axis of the earth isn't perpendicular to the to the orbital plane (it's the same as the equatorial plane discussed above but I find it easier to visualize the axis). We generally think that max/min ellipsis orbital distance is also when the tilt is maximum toward the sun. That is not the case. It is off by a few weeks and precesses. Axial tilt is what drives the seasons but sunset and sunrise are affected by axis relation to orbit. I believe if the tilt and the orbital ellipse were aligned, the days would be the same. The effect of precession is that the earth is closer to sun for one equinox (moving faster, shorter day) and further away (moving slower, longer day) for the other. This averages out over the year. When the axial tilt is aligned to either the major or minor axis of the ellipse, the orbital times for the uquinox and solstice will match I believe. --DHeyward (talk) 04:55, 26 November 2014 (UTC)

Is Power supply a misnomer?

It doesn't actually supply the power, it merely converts it. ScienceApe (talk) 18:52, 22 November 2014 (UTC)

Supply "​(transitive) To provide (something), to make (something) available for use". [15] It provides the power in the form required. You could say the same thing about the water supply - and I don't recommend you asking for your water bill to be reduced because the supplier isn't making the water, just passing it on. AndyTheGrump (talk) 19:02, 22 November 2014 (UTC)

By this assumption, the big bang would be the power supply, and since then there has only been conversion. Power supply is a human concept used for convenience in a certain context, not a scientific primary. μηδείς (talk) 19:53, 22 November 2014 (UTC)

Might as well protest that a butterfly is not a fly made out of butter. That's just the way language works. 88.112.50.121 (talk) 22:06, 22 November 2014 (UTC)

Corollary, by Carl Sagan: "If you wish to make an apple pie 'from scratch', you must first invent the universe." ←Baseball Bugs ^{What's up, Doc?} carrots→ 05:04, 23 November 2014 (UTC)

Generally, a power supply supplies power at a particular voltage, AC/DC value, with or without smoothing, with or without current limiters. So a 5 volt power supply does indeed 'supply' 5 volt power. The fact that it happens to get the energy to do this from 110 volt AC isn't really any different than if it was supplied from a steam turbine or solar panels or whatever. They all convert energy from one form to another. SteveBaker (talk) 00:59, 23 November 2014 (UTC)

When I was a kid and had a model train set, way back in the 1950s and 60s, power for the train was supplied by a transformer. It had the obvious function of transforming the 240V AC mains supply to a 12 V DC supply for the trains. I later worked for our local electricity supplier, and learnt they used transformers too, only they involved much higher voltages. Dunno why that name is no longer used. It was a good one, and we have an article on it. HiLo48 (talk) 03:00, 23 November 2014 (UTC)

(Since we're already on about semantics) ... People still use the term "transformer," but only when referring to a transformer. Not all transformers are part of a power supply. Not all power supplies use any transformer at all. The relationship between the terms "transformer" and "power supply" is the same as the relationship between the words "tunafish" and "lunch" - you can make lunch using tunafish, but you don't have to; there are plenty of cases where you must use tunafish for lunch, and some cases when you cannot use tunafish for lunch; and there are plenty of things tunafish can be in that isn't lunch. Nimur (talk) 03:10, 23 November 2014 (UTC)

Yeah - I remember that too. But even then, the name wasn't "right". The "transformers" we had used an actual wire-wound transformer that turned AC 240 volts down to AC 24 volts - which was reduced in voltage using a rheostat and chopped to make really rough "DC" at 0v up to 12v. So only a part of what was inside the black metal box with the big red plastic knob on it was actually "a transformer"...so even that was a misnomer.

Triang or Hornby? My parents bought me Triang - but I always suspected that Hornby was better.)

SteveBaker (talk) 05:15, 23 November 2014 (UTC)

The "chopping" was done with a rectifier. Was a centre-tap 24v transformer cheaper than a 12v simple transformer plus a bridge rectifier? I remember only the latter. Dbfirs 08:16, 23 November 2014 (UTC)

The change in terminology is a result of changing technology. Modern switched-mode power supplies have replaced the old transformer-based power supplies in many (most?) applications.--Srleffler (talk) 08:09, 23 November 2014 (UTC)

I'd like to see a drugs supplier try and get off in court using that sort of reasoning. 'I'm not a supplier, I merely conduct it from some transformers'. yeah I can see them walking - not! Dmcq (talk) 12:13, 24 November 2014 (UTC)

Oestrogen and womens' facial and bodily features

I am aware that oestrogen promotes prototypically feminine facial (i.e. small jaw and nose) and bodily features (i.e. low waist–hip ratio). My question: if oestrogen is the primary determinant of these, presuming it is, why aren't these features perfectly, or near-perfectly, correlated? Anecdotally, I have seen significant discrepancies,that is, I have seen women who have feminine features in some regards and not others.

Also, are proportionally-longer legs an indicator of high oestrogen in adolescence? Perhaps I'm being stupid, but I have yet to find a reliable source on the matter.--Leon (talk) 22:07, 22 November 2014 (UTC)

It is better to describe it as (one of many) precondition(s) because it does not determ the developement of a human body. Additionally it seems cultural behavior has a much bigger impact when you compare this to humans in "primitive" cultures, who generally seem to develope more "sporty". --Kharon (talk) 15:13, 23 November 2014 (UTC)

Actually, while estrogens play a very central role in dimorphic differentiation, including numerous secondary sexual characteristics, it is actually androgens (testosterone in particular) that drive the bulk of differentiation between male and female faces, by causing the increased size of the jaw and nose that you reference as well more pronounced brow contours, and changes in the relative sizes and shapes of various other facial features. In this sense, the traits which predominate in many aspects of the female faces are sometimes regarded as the "default", though this is a bit of an oversimplification. Waist-hip ratio, on the other hand is driven more by estrogens. It's worth noting though that women tend to vary a little more in their secondary sexual characteristics and the development of such features in both sexes can be influenced by both genetic variation and circumstance (including nutrition, stress exposure, and any number of other environmental factors). Leg length, and body proportions in general, are less likely to be powerfully influenced by sexual dimorphic hormones than secondary sexual characteristics and on the whole more determined by individual genetics and epigenetics (again, notably diet and stresses during childhood and adolescent development). Snow talk 11:42, 24 November 2014 (UTC)