Wikipedia:Reference desk/Archives/Science/2011 December 5

= December 5 =

Has the mass of our sun or things in our solar system ever been measured with gravitational lensing?
Has the mass of our sun ever been measured with gravitational lensing? Normally mass is measured http://imagine.gsfc.nasa.gov/YBA/cyg-X1-mass/mass-of-sun.html http://en.wikipedia.org/wiki/Mass_of_Sun in this sort of pre-Einstein way. I cannot find any source where it's been measured with gravitational lensing. Same for planets in our solar system (I don't mean planets in other solar systems). So anyone know of our sun, planets, or moons in our solar system being measured by gravitatonal lensing? It would be interesting to compare the gravitational lensing vs. pre-einstein-type measurements and see if they match. Are you ready for IPv6? (talk) 00:56, 5 December 2011 (UTC)


 * Well, Eddington's observational confirmation of relativity during the Solar eclipse of May 29, 1919 showed the lensing effect was as predicted given the estimated mass of the Sun. -- Finlay McWalterჷTalk 01:06, 5 December 2011 (UTC)

Rate equations
Have I derived the following 6 differential equations correctly? This isn't something I've done before and I want to be absolutely sure I'm correct. 184.98.169.135 (talk) 02:17, 5 December 2011 (UTC)
 * 1) A <-> B
 * dA / dt = k_r [B] - k_f[A]
 * dB / dt = k_f [A] - k_r[B]
 * 1) A -> B + C
 * dA / dt = -k_f [A]
 * dB / dt = k_f [A] / 2
 * dC / dt = k_f [A] / 2
 * 1) A -> B
 * dA / dt = -k_f[A]
 * dB / dt = k_f [A]
 * 1) A -> A + B
 * dA / dt = 0
 * dB / dt = k_f [A]
 * 1) A + A <-> B
 * dA / dt = k_r [B] / 2 - k_f [A]^2
 * dB / dt = k_f [A]^2 - k_r [B] / 2
 * 1) A + B <-> C
 * dA / dt = k_r[C] / 2 - k_f[A][B] / 2
 * dC / dt = k_f[A][B] - k_r[C]
 * dB / dt = k_r[C] / 2 - k_f[A][B] / 2


 * You're close, but you'll want to check your equations for the second, fifth, and sixth reactions. For example, for reaction #2, each mole of A consumed results in a mole of B and a mole of C formed, therefore dB/dt = dC/dt = -dA/dt.  The way that you've written your differential equations assumes that for each mole of A consumed, half a mole each of B and C are formed. TenOfAllTrades(talk) 02:39, 5 December 2011 (UTC)

Wind energy and health
Hi. Recently in Ontario there have been many protests and also legal action against the installment of wind turbines (to verify, do a Google News search). Many rural families claim that the turbines cause effects such as vertigo, dizziness, insomnia, headaches, myalgia, and other complications. Yet why are these cases seemingly limited to Canada, and are there any similar complaints from other countries, and are they covered in Wikipedia? Thanks. ~ AH1 (discuss!) 02:57, 5 December 2011 (UTC)


 * You might find your questions answered in one or more of these documents.
 * ACOUSTIC ECOLOGY | Special Report: Wind Energy Noise Impacts
 * Wind Turbine Syndrome: A Report on a Natural Experiment
 * Responses of the ear to low frequency sounds, infrasound and wind turbines
 * The Ear, Infrasound and Wind Turbines
 * See also the article "Environmental impact of wind power”.
 * —Wavelength (talk) 03:12, 5 December 2011 (UTC)


 * Ohio's highest point is located in the county where I grew up. A few years ago they tried to put in turbines, but protestors made similarly absurd claims — and even more unrealistic ideas as well, such as the idea that turbines cause seizures and that they're so loud that they will cause deafness.  It can't be that often that you find an issue on which hardline Greens oppose the renewable energy source...Nyttend (talk) 04:42, 5 December 2011 (UTC)


 * Like when those hypocritical eco-Luddites (such as Nina Pierpoint, who apparently wants to send the whole country back two hundred years) demonstrated against the Mojave Desert solar plant on the pretext that "the construction methods used to build the plant involve toxic materials" (even though they don't)? BTW, I'm not a fan of solar power (too many problems with it, both technical, economic and geopolitical), but those people's position on these issues clearly demonstrates that they're not so much interested in reducing pollution as they are in depriving the civilized world of all the benefits of modern technology. 67.169.177.176 (talk) 05:06, 5 December 2011 (UTC)


 * Presumably you mean Nina Pierpont. -- ToE 11:27, 5 December 2011 (UTC)


 * I did a very (very) quick search of Polish-language Internet (we have been having literally tens or even hundreds of new turbines installed in recent years and loads more are on the way), and I found local inhabitants' protests appealing to poorly written plans of wind farms, lack of wind, destruction of the landscape (this one was the topic of a protest somewhere in a mountainous region), or without citing a reason - it was just that the people plainly didn't want turbines close to their homes, full stop. No appeals concerning health or related issues (but this was a quick search though). Sorry for the brevity but I've got a project to hand in this morning. --Ouro (blah blah) 06:58, 5 December 2011 (UTC)


 * Editor 67.169.177.176, wind turbines have caused health problems to many people. Which is more important: technological benefits or human health?
 * —Wavelength (talk) 17:18, 6 December 2011 (UTC)


 * Editor Wavelength: No they haven't, except in anecdotal reports from technophobic nutjobs like Pierpont (who are most likely pursuing an agenda to return our country back to the stone age, considering their opposition to all other energy sources, whether dirty or clean). The vast majority of peer-reviewed reports indicate little or no impact on human health.  Besides, what's worse, a few cases of insomnia in a small percentage of the population, or worse effects on human health from other energy sources (air pollution from conventional "dirty" coal plants, etc.), or maybe having to do without any kind of energy at all (which is what will happen if the green luddites have their way)?  Are you really so dumb as to believe the crazy fanatics, or are you pursuing a political agenda? 67.169.177.176 (talk) 01:49, 7 December 2011 (UTC)


 * Here are a few points in reply.
 * If you see my first post above and read the pages to which I have linked, you can learn about many people in many places with health problems. Also, there are links to additional pages with additional information.
 * If you see this page and search for arousal, you can read what Dr Christopher Hanning has said.
 * Many humans make inadequate use of human energy.
 * Much energy is wasted on the overproduction and overconsumption of non-essential items.
 * Many cities can promote energy conservation by improving walkability.
 * Nina Pierpont and I do not need to be ahead of our time in recognizing the health hazards of wind turbines. I hope that you have an honest heart and an open mind.
 * —Wavelength (talk) 03:33, 7 December 2011 (UTC)


 * Aha, just like I thought -- another Luddite trying to end "overproduction and overconsumption of non-essential items" (i.e. any semblance of prosperity and modernity in everyone's way of life). Very well then, why don't you start practicing what you preach -- get rid of your computer, sell your car for scrap, start using "human energy" in all your household tasks (that means you do everything by hand -- no vacuum cleaners, no washing machines or clothes dryers, no dishwashers, no blenders, no nothing), and use torches instead of electricity for illumination, and let's see how long it will take until you start wishing for your "non-essential items" again.  By the way, if your goal is to end humanity's dependence on electric power, how come you're even using a computer and the Internet in the first place, hypocrite?! 67.169.177.176 (talk) 07:48, 7 December 2011 (UTC)
 * And as far as the linked documents in your first post are concerned, they are all authored by Luddite nutjobs like Pierpont and you, and have zero credibility in the scientific community. 67.169.177.176 (talk) 07:53, 7 December 2011 (UTC)


 * Here are some comments in reply.
 * According to hypocrite, a hypocrite is "[s]omeone who practices hypocrisy, who pretends to hold beliefs, or whose actions are not consistent with their claimed beliefs." I did not claim to be perfect.  You and I are imperfect humans in an imperfect world (that is to say, in an imperfect societal arrangement).  We do not need to take an all-or-nothing position in regards to doing good.  Each person can do his or her best in an imperfect situation.
 * You do not know my net environmental footprint. You do not know what environmental adjustments I have already made.  You do not know how I travel or how much I travel.  With a few exceptions, you do not know my abilities and you do not know my needs.
 * If everyone else in my community wants to drive a motorcar, and if the infrastructure is designed for the motorcar, and if the local government has outlawed the use of horses and buggies on local thoroughfares, then who would expect me to travel by horse and buggy on local thoroughfares?
 * One person can not necessarily make a big difference, but one person can still make decisions according to principles. A decision made according to right principles can make a difference for the better .  If everyone makes decisions according to right principles, then collectively they can make a big difference for the better.
 * Each person can invite and encourage others to make decisions according to right principles, but ultimately each person is an agent of free will. We can lead a horse to water, but we can not make it drink.
 * —Wavelength (talk) 19:37, 7 December 2011 (UTC)


 * Here are some comments in reply to YOU:
 * (1) Regardless of any adjustments you might have made, you have still shown yourself to be a hypocrite by using a technology that consumes electricity on a continuous basis (i.e. your computer), while at the same time opposing the production of electricity even from such clean and renewable sources as wind power. Need I say more?
 * (2) Is there ANYONE in his/her right mind who would choose to travel by horse and buggy in this day and age, even if the infrastructure and municipal laws allow for it? Traveling by motorcar is so much superior in every practical respect to travel by horse and buggy that only an incurable Luddite would choose the latter.
 * (3) What makes you think that principles which limit economic development (as evident from your comments about "overproduction and overconsumption of unnecessary items") are the right ones? It is PRECISELY the unrestricted exploitation of our energy resources (among other things) that made the USA into the most prosperous nation in the world, and any principles that would diminish our prosperity (such as those that call for limiting such exploitation, as you are doing) by definition CANNOT be right ones or make a difference for the better.  (Not unless by "making a difference for the better" you mean "turning our country into a third-world nation and forcing everyone to travel by horse and buggy instead of by motorcar"!) 67.169.177.176 (talk) 07:29, 8 December 2011 (UTC)


 * Do you see the differences?
 * (1) There is a difference between "production and consumption" and "overproduction and overconsumption".
 * (2) There is a difference between the sound of a motorcar and the sound of a horse and buggy. See The Surrey with the Fringe on Top and OKLAHOMA &quot;The Surrey With The Fringe On Top&quot; with lyrics - YouTube.
 * (3) There is a difference between ecological extremism versus economic prosperity and economic extremism versus ecological prosperity.
 * —Wavelength (talk) 06:39, 9 December 2011 (UTC)


 * OK, watch me demolish your arguments one by one:
 * (1) First of all, "overproduction and overconsumption" is a purely arbitrary concept -- in reality, every economy strives (and SHOULD strive) to maximize production and expand its production possibilities frontier in order to maximize prosperity for each and every person who is part of that economy. The moment you start placing arbitrary limits on production, you limit economic prosperity for EVERYONE in the country and send the economy back on the way to collapse and destitution (as can be seen from the example of the USSR, where the government outlawed private enterprise and placed arbitrary limits on the accumulation of wealth).
 * (2) The sound of a motorcar vs. that of a horse and buggy is irrelevant to this discussion -- the practical advantages of a motorcar (speed, comfort, payload) are so overwhelming that to propose replacing it with a horse and buggy based merely on the difference in sound is completely preposterous!
 * (3) There's no such thing as "ecological prosperity" (unless you invented this concept) -- economic prosperity is what matters to any normal person (unless you prefer to live like a hermit in the woods), so unless you're ready to concede defeat you better at least define "ecological prosperity" AND PROVE that it should matter as much as, or more than, economic prosperity. 67.169.177.176 (talk) 06:58, 9 December 2011 (UTC)


 * Wind power seems like a bit of a NIMBY issue. That is, while most people like the idea in theory, they don't want huge wind turbines near them.  Of course, many other power sources have a similar issue, as nobody wants a coal-fired plant, a nuclear plant, etc. next door, either.  However, since wind farms must be spread over wider areas, they are likely to be in more people's "back yards".  Solar collectors have the advantage of not being noisy and not having pieces that can fly off at high speeds, so they might be a bit more acceptable. StuRat (talk) 20:24, 5 December 2011 (UTC)


 * At the price of being much more expensive and less efficient. 67.169.177.176 (talk) 23:55, 5 December 2011 (UTC)


 * Solar does have the advantage of providing the most energy on sunny days, which, during summer, is when our electrical supply is the most overstretched by air conditioners and subject to brownouts or blackouts. So, while not suitable as a primary electrical supply, it makes a good supplemental source. StuRat (talk) 17:58, 6 December 2011 (UTC)


 * Perhaps -- but the high production costs still makes them uneconomical without government subsidies. 67.169.177.176 (talk) 01:51, 7 December 2011 (UTC)


 * Additional nuclear and coal-fired power plants to supply peak-energy needs also require subsidies, usually in the form of approval for higher rates to customers. StuRat (talk) 20:13, 9 December 2011 (UTC)


 * I should say that there is no doubt in my mind that wind turbines can ruin a neighborhood - for example, there is a formerly very pleasant state gameland near Aristes, Pennsylvania which included a secluded valley, isolated by hills from all roads, one of the few remaining spots in its entire region unspoiled by machine noise, except when planes (frequently) flew over. Now one of those hills is lined with the turbines and the feel of the area is just ruined.  That's the sad end of the NIMBY-based decision making - the unspoiled places are singled out for destruction.  The big disappointment with wind power for me is that there are vast, vast tracts of empty land blasted by the noise of adjacent major highways, but there is no effort at all to place these things in the area that is already ruined.  Like the illegal dumpers who each somehow manage to find a way far from the beaten path so that they can dump their own waste somewhere never before defiled, the noisemakers of wind power apparently take no satisfaction from ruining what is already ruined. Wnt (talk) 20:48, 7 December 2011 (UTC)


 * See Wind Powering America: Siting Wind Turbines, with a link "Siting Considerations in New England", New England being near to Pennsylvania.
 * —Wavelength (talk) 21:49, 7 December 2011 (UTC)


 * Wind turbines are (and SHOULD BE) placed where the wind is strong and fairly constant -- any effort to prevent the best possible sites from being used for wind power production merely on the grounds of it being an "unspoiled place" is nothing more than blatant hypocrisy on the part of environmental activists. I mean just think of it, first they demand that renewable power be used for ALL of our country's energy needs (even though it would be completely impossible for renewables to meet 100% of our electricity consumption, or to be even remotely useful for transportation), but then when it comes time to actually BUILD the dam site (or the windmill, or the solar plant -- not necessarily hydropower), all of a sudden they come up with some moronic pretext (like "infrasound emissions" in this case) to OPPOSE renewable energy?!  What hypocrites! 67.169.177.176 (talk) 07:41, 8 December 2011 (UTC)


 * Sound is also part of the environment. The myriad species of birds, insects, and mammals coordinate their calls, among the sounds of the trees and grasses and wind and rain, like the instruments of a symphony, each with its own frequencies and times and places of transmission to maintain a natural order.  The universal and perversely deliberate destruction of this beauty wherever it can be found is not merely a tremendous oppression to the human ear and spirit, but also damaging to human cardiovascular health and intellectual development.  And in the long run, I fear it will lead to the destruction of even the potential for nature to sing these songs.  When insects and birds and mammals compete with cars and air conditioners and wind turbines to be heard, the old parameters of natural selection are set aside.  Each player, without feedback, loses its well-rehearsed talent - and collectively, they will no longer be able to integrate with one another in the old ways.  What is being destroyed is not merely the sound of nature here and now for you and I, but in its entirety. Wnt (talk) 03:59, 9 December 2011 (UTC)


 * And for that reason you want to deprive everyone of electricity, you Luddite? Well, I got news for you -- EVERY aspect of EVERY civilization (whether bronze smelting in ancient Greece, textile-making in Renaissance England, or electricity generation in America today, no matter how clean or renewable) WILL have an impact on nature, so unless you wanna have everyone go back to the stone age, you better get used to it and stop bitching about the "destruction of natural beauty"!  It's the price to pay for not having to live in caves and hunt buffalo with flint spears, so get over it! 67.169.177.176 (talk) 06:37, 9 December 2011 (UTC)
 * But we pick and choose which impacts we accept and which we reject, according to our values. We do that the moment we have any regulation against any form of pollution whatsoever.  Just because you don't want to live in a cave doesn't mean you want to have a heart attack or asthma from noise or pollution just so that some rich fellow can ride a lift up a hill and slide down the artificial snow under brilliant spotlights all night long.  We make choices about what we value and defend.  My values are such that I would accept a line of windmills in public land along a major highway, because the area ruined by noise is reduced, and excuse the toll on migratory birds and the degradation of the visual appearance to passing motorists for the benefit of decreasing imported fossil fuel use and carbon emissions.  I hardly consider myself a fanatic - I am more than willing to accept cheap coal power provided that real and serious effort is taken toward reducing all of its environmental impacts, such as carbon sequestration and avoiding acid rain, and provided that the damage done by mining is strictly limited.  But the song of the land has been so terribly oppressed, throughout the land and even in the depths of the sea, and those few places where it remains need meaningful respect. Wnt (talk) 15:15, 9 December 2011 (UTC)

The annoying ambivalence of domestic cats
You know the sort of thing: they come to you for a pat, you start doing so, they walk away a few paces then plop down so you have to move or lean over awkwardly to reach them... It doesn't happen every time, but it is a characteristic of every cat I've been friends with. What gives? It's like they all belong to Schrodinger - never in one state or another...

I have my theories, but rather than speculation or original research, I'd rather the answers were actual findings by someone or other - zoologists, maybe?

Thanks Adambrowne666 (talk) 03:17, 5 December 2011 (UTC)


 * I've noticed the same behavior. StuRat (talk) 03:39, 5 December 2011 (UTC)
 * We have lots of articles, like Cat behavior, Cat intelligence and Cat communication. One thing to keep in mind is that cats were domesticated somewhere around 10000 years ago, so whatever the answer is, it certainly does not have to be in terms of natural selection. Vespine (talk) 04:46, 5 December 2011 (UTC)
 * There's a book about this. I personally find that ambivalence one of their most appealing qualities. They make you earn their affection. Shadowjams (talk) 07:16, 5 December 2011 (UTC)
 * Thanks, all, but I don't feel I have the answer yet - the only thing close to one is in Cat behaviour, about their mistrust of predator species such as humans, suggesting that even when they want to be close they feel an anxious need to be distant at the same time... Still, it's not explicitly stated in the article - I'm still hoping there'll be some research somewhere someone can cite specifically on this subject... Adambrowne666 (talk) 09:28, 5 December 2011 (UTC)
 * I think the explanation is relatively simple. Cat fur is well known for its electrifying properties. When you stroke a cat for two long, it gets electrically charged up to the point where the cat is experiencing little electric shocks. Maybe cats feel them stronger than we do, or maybe cats are more afraid of them and therefore are particularly keen on avoiding them. In any case, for the cat it's a balance between the pleasant feeling of being stroked and the nasty feeling of getting electric shocks when being stroked too long. Hans Adler 09:40, 5 December 2011 (UTC)
 * Or maybe I am wrong. See www.ehow.com/how_5877799_rid-static-electricity-cat_s-fur.html for some related information that could help to check my hypothesis. (Certainly not a reliable source, but seems reasonable in this context. Due to the spam filter I can't make it clickable.) Hans Adler 09:55, 5 December 2011 (UTC)
 * This is a behavioral issue, not an electrical one. Searching for "petting aggression" or "status-related aggression" will provide many (but mainly low quality) sources which share the opinion that [1] cats have a limited tolerance for grooming or petting, [2] individual cats vary in their degree of tolerance; [3] cats learn quickly they can end unwanted petting by biting, scratching, nipping, or if the owner is lucky, just walking away. - Nunh-huh 12:15, 5 December 2011 (UTC)


 * Yeah. Cats are not quite social animals (unlike dogs/wolves). Males are strictly solitary hunters and females only gather in casual groups with their young (and only if resources and shelter are plentiful). In domestic cats that are wary of being stroked or held, this is simply the remnants of escape behavior. The cat deliberately moves some distance from you as to give him more chances of getting away if ever the stroking turns to a grip and you decide to eat him. :D While they probably trust you somewhat and definitely like being stroked, being confined is still a viscerally unpleasant situation to be in.


 * A lot of adult cat behavior depends on how you treated them when they were young. Lack of enough human interaction in the first eight weeks leads to adults just that little bit more distrusting of humans than kittens who did. Our article on Cat mentions one of the reasons as behavioral neoteny. They are basically retaining childish (kittenish?) behaviors with humans who reared them and who they view as their own mothers.


 * And lastly, cats are individuals as well, and they do differ in behavior. Some cats are naturally affectionate, some are irritatingly aloof, and some cats get freaked out way too easily. We have two adopted strays here and while they've grown to be very comfortable around humans and like rubbing themselves against people's legs, they can't stand being held at all. Even petting them with curved hands prompts them to pull away (I suppose because it feels uncomfortably close to being gripped). --   Obsidi ♠ n   Soul   14:39, 5 December 2011 (UTC)


 * If you want a cat to move away you gently 'pat' it. If you not mind it sitting on your lap then you stroke it. Why do you think it wants to stick around if your patting it? Cats don't like that. --Aspro (talk) 16:50, 5 December 2011 (UTC)


 * I assumed that was a typo and they meant "pet", but perhaps we need a clarification. StuRat (talk) 20:16, 5 December 2011 (UTC)


 * More likely an WP:Engvar issue. Patting a cat normally means stroking it gently in New Zealand, Australian (like the OP) and probably British English. See       . Petting may also be used but is possibly less common. In fact the online OED specifically defines pet as 'stroke or pat (an animal) affectionately'. It doesn't mean to gently smack it or push it away as in the way you may pat someone on the back, which I guess Aspro and StuRat are referring to. Nil Einne (talk) 22:01, 5 December 2011 (UTC)


 * Found which suggests stroking may be more common in some varities of British English but supports the idea patting is more common in Australian English. Nil Einne (talk) 22:16, 5 December 2011 (UTC)


 * I saw a bit of the "Nature" program on PBS, which showed a shelter with an elaborate color-coded scoring system for cats. A guy would stroke it five times - some would stay near, some would try to get away before the end of the five strokes.  The ones trying to get away were deemed unsuitable for families with children.  I should chase it down to reference, but somehow didn't work up the interest. Wnt (talk) 19:53, 5 December 2011 (UTC)


 * Thanks heaps, everyone - it seems to be a consensus now - certain cats are ambivalent between closeness and freedom, just like us... And yes, the 'pat' thing was a dialect issue - in Aus, pat and stroke are often used interchangeably - amazing detective work, Nil Einne. Adambrowne666 (talk) 05:47, 6 December 2011 (UTC)


 * And how about "pet" ? Can you pet a cat there ? StuRat (talk) 17:55, 6 December 2011 (UTC)


 * Not really; it would sound American if someone said that; it's almost exclusively a noun over here. Adambrowne666 (talk) 00:15, 7 December 2011 (UTC)


 * Is Down Under the land of heavy patting? -- 203.82.66.202 (talk) 03:08, 7 December 2011 (UTC)


 * At times, I'm glad to say. Though we have no heavy petting zoos.Adambrowne666 (talk)


 * And does pat mean both stroke and tap there ? (In the US it only means tap.) StuRat (talk) 04:20, 7 December 2011 (UTC)


 * It does, which isn't all that convenient, actually. Using the word 'stroke' usually results in someone making a double entendre - even though it's a perfectly innocent word, it seems to be used here only in a sexual context...Adambrowne666 (talk) 00:14, 8 December 2011 (UTC)

Heat Transfer (Hollow Fin)
If we have a hollow tube and its one end is at fixed temperature, then, how to calculate the temperature at other end?Anujkumardeo (talk) 06:44, 5 December 2011 (UTC)
 * Is it hollow and filled with air or hollow and filled with a vacuum? -- Jayron  32  14:20, 5 December 2011 (UTC)
 * Yes, to get a specific answer, we need to know more about the initial conditions. In general, this is the kind of question that can be (in principle) answered by setting up and solving a heat equation. SemanticMantis (talk) 14:24, 5 December 2011 (UTC)
 * Depending on the material's thermal conductivity, we may be able to ignore some of the complexity of this problem. In the simplest case, a hollow tube can be modeled with the one-dimensional heat equation. Our article presents an analytic solution.  It may be reasonable to neglect the fact that the object is tube-shaped; or that it is filled with convective or flowing air.  All these depend on the specific details of the problem.  Nimur (talk) 19:14, 5 December 2011 (UTC)


 * The other end is open, however, if we can have a easy solution by neglecting the air in the tube, its ok for me. — Preceding unsigned comment added by Anujkumardeo (talk • contribs) 08:23, 7 December 2011 (UTC)

Mass of chick and egg
Does the weight of a “just laid egg” and that of a “just born chick” be the same? If no, what about law of conservation of mass?

If yes, does the chick inside the egg grow without gaining mass?Brahmarishiraj (talk) 11:08, 5 December 2011 (UTC)


 * Presumably you mean "just hatched chick", as a chick isn't "born", that term applies mainly to mammals. StuRat (talk) 17:51, 6 December 2011 (UTC)


 * Eggs typically lose about 10% of their mass during incubation, mainly due to evaporation of water. --Colapeninsula (talk) 12:06, 5 December 2011 (UTC)


 * The simple answer to the first original question is "yes". There are minor inaccuracies such as the one mentioned by Colapeninsula. --Heron (talk) 15:53, 5 December 2011 (UTC)


 * And the simple answer to the second question is that the chick grows by digesting the contents of the egg. See our article on egg.--Shantavira|feed me 16:05, 5 December 2011 (UTC)


 * Except the shell, of course, so it's mass isn't added to the chick. StuRat (talk) 16:08, 5 December 2011 (UTC)


 * And the waste products in the allantois, which stay behind. Wnt (talk) 19:51, 5 December 2011 (UTC)


 * It seems conceivable that the mass might even increase: the egg is permeable, and air can enter. A similar experiment is to measure the mass of a bean-sprout or other plant, and compare it to the mass of the bean that was originally planted.  In the case of the plant, the absorbed carbon and water from the atmosphere ends up undergoing respiration and conversion to starches; the result is that the final plant weights much more than the seed it started from.  I don't think the same is true for a chicken that emerges from an egg; but this would make an excellent science-experiment.  Nimur (talk) 23:05, 5 December 2011 (UTC)


 * A fundamental difference is that the bean-sprout is a plant, which extracts carbon and water from the air (emitting a lesser mass of oxygen), whereas the chicken is an animal that would do the reverse, if anything. Mitch Ames (talk) 01:24, 6 December 2011 (UTC)


 * Agreed. And if the chick did expand, it would crack the egg prematurely, unless the egg was flexible and could also expand, or there was a lot of empty space inside to begin with. StuRat (talk) 17:50, 6 December 2011 (UTC)

Which program prevents sexual harassment the best?
Which "one study demonstrated sustained behavioral change" in and where can I read more about that one study? Thanks. 67.6.191.142 (talk) 11:55, 5 December 2011 (UTC)
 * You'd have to download/purchase/read the entire article, and that particular study will be named in the article (in the references or literature). --Ouro (blah blah) 13:06, 5 December 2011 (UTC)
 * Yes, I've tried emailing the author and WP:RX without luck so far. I only want to know that one fact. Is there anyone here on the reference desk who can access it and share the pertinent study citation? 67.6.191.142 (talk) 14:10, 5 December 2011 (UTC)

It's Foubert, J. (2000) "The Longitudinal Effects of a Rape-prevention Program on Fraternity Men's Attitudes, Behavioral Intent, and Behavior" Journal of American College Health 48(4):158-63. 67.6.191.142 (talk) 14:53, 5 December 2011 (UTC)
 * full text 67.6.191.142 (talk) 19:52, 5 December 2011 (UTC)

exact meaning of unit phon
what is the exact meaning of the unit phon in sound?Shrikant chavan (talk) 12:57, 5 December 2011 (UTC)
 * See Phon (not a very good article). Basically a phon measures how loud a sound is perceived to be, taking into account that human beings don't perceive all frequencies equally.  In contrast, measures of sound intensity like the dBSPL only take into account the energy or pressure of a sound wave, not how humans perceive it.  Equal-loudness contour shows the differences in perception of different frequencies. --Colapeninsula (talk) 13:44, 5 December 2011 (UTC)

How to progress ...?
Assume I have some technological or anything, ideas and plans, and I have no money. is incubator programs good choice for me,or it's another thing, or it depends on the program? Flakture (talk) 15:46, 5 December 2011 (UTC)


 * Anyone who will lend you money will want a part of the profits, unless you have generous friends or family who can lend you enough to get started. StuRat (talk) 16:11, 5 December 2011 (UTC)


 * It's more than just a part of the profits; people with money can and will take over the business in very short order; being the originator of an idea with no capital to bring it to fruition means very little to the venture capitalists that fund your idea. Indeed, it is rare for a broke person with a good idea to make the money on their idea that they think they are due; they rarely end up in control of the company founded to produce their idea; instead that goes to the person who either fronts the bulk of the cash and/or someone with the best business acumen who is good at getting the cash.  See Bill and Scott Rasmussen who founded ESPN, but were left out of control of their own idea as Getty Oil, who fronted the cash, very quickly took control of the business.  See also Eduardo Saverin, co-founder of Facebook who was edged out of the company by the venture capitalists who funded the expansion.  See also Steve Wozniak who was the brains behind building the first Apple computers, but who never had much control over the company's management; that fell to Steve Jobs who probably couldn't have built a computer, but who had the head for business and marketing.  There are numerous other examples.  It's a catch-22 for someone with a really good idea: if you don't secure the capital, you can't bring your idea to market.  In order to secure the capital, you have to give up control of your idea (and the vast bulk of the profits that come from it) to someone that does.  A good rule of thumb is that the idea is basically free; you're share of the profit is the same as the share of the company you own.  If your company is worth $100,000 and some venture capitalists front $10,000,000 for your "idea", then you can expect to be able to get 1% of the profit from the company.  And, likely, no control over it.  -- Jayron  32  18:18, 5 December 2011 (UTC)
 * I agree with Jayron's sentiment. But this shouldn't be a surprise: it's really the definition of Capitalism - venture or otherwise.  "Capitalism" is predicated on the economic theory (...really, on the economic reality) that control of the means of production, via the ownership of capital, directly equates to having the upper hand in negotiations of profit sharing.  A good idea is a tiny tiny fraction of a good business, and as a result, it's not really very highly rewarded in comparison to all the other aspects of a good business.  Take, for example, a commodity business like PepsiCo.  They sell sugar-water, grain-based snacks, and fast-food takeout.  Are these "innovative new ideas"?  Not in the slightest!  Bread and water have been staples of the human diet since prehistoric time!  And yet, by market capitalization, this company is among the largest players in the world.  The reason for the success of such a business has little to do with their innovation - it's directly a result of the capital that they already own.  Pepsi can own the supply-chain that delivers a very large percentage of the snacks and soft-drinks.  You don't own that supply-chain: so even if you provided a comparable beverage or snack - even if you innovated and produced a revolutionary better new beverage or snack - you still don't own the means of production (in this case, the retail distribution network).  The issue is even more heightened in technology-dominated industries.  For example, consider operating system software.  A free alternative exists that can drive all types of modern computer hardware; and yet, almost 100% of computers run a commercially-purchased operating system.  This is because major capitalists own the distribution networks that provide software for computers.  You can't force the owners to use something that is contrary to their own interests.  In today's technology industry, the means of production include not only factories and tools, but also access to markets via economic control of critical infrastructure.
 * The intelligent entrepreneur must realize this limitation: you must find a way to align your innovation so that it benefits the venture-capitalist who finances your project. There is no easy way to make this happen.  Various business schools across the country purport to train individuals in skills that are relevant to entrepreneurship; yet, few people actually go out into the real world and start successful technology ventures.  It's more difficult than an academic problem; a classroom environment can not really prepare most people to succeed at that task.  Nimur (talk) 19:08, 5 December 2011 (UTC)
 * Would patenting and then selling the patent work? Heck froze over (talk) 18:50, 5 December 2011 (UTC)
 * In theory, it could. In practice, probably not. In the modern USA, it is quite expensive to secure a patent, and most patents are awarded to companies/universities, not individuals. If you have the money and expertise to patent a technology, you likely have the money and expertise to develop your product/process. SemanticMantis (talk) 19:27, 5 December 2011 (UTC)
 * Strictly speaking, patents are awarded only to individuals. APL (talk) 20:59, 5 December 2011 (UTC)
 * I know, my question was whether Flakture could patent and then sell the patent? Heck froze over (talk) 16:32, 6 December 2011 (UTC)
 * Crowdfunding was missing Crowd_funding so I added it. 67.6.191.142 (talk) 23:20, 5 December 2011 (UTC) And they were immediately reverted without explanation or discussion. Imagine that! Reversion without discussion or explanation in your Wikipedia? It's more likely than you think! Anyway, they were http://kickstarter.com, http://www.thepoint.com, http://www.ulule.com, and http://www.rockethub.com. Good luck! 67.6.191.142 (talk) 23:47, 5 December 2011 (UTC)
 * Hello 67.6.191.142. An explanation of the revert would be good but this is not the right place to ask for that explanation.  Possibly the explanation is that the purpose of an encyclopedia article is to explain the topic, not provide links to people's fav pages.
 * Please can you explain what crowd funding has to do with the question asked here by Flakture?  Thanks, CBHA (talk) 00:41, 6 December 2011 (UTC)
 * The connection is pretty clear, if you have a good idea, but no capital, crowd-funding is a way to get capital without giving up control of your idea, or incurring obligations you can't fulfill.
 * Crowd-funding does have it's limitations, so depending on the nature of the "idea", crowd-funding may or may not be appropriate. APL (talk) 00:56, 6 December 2011 (UTC)

What Vehicle is this?
http://img.photobucket.com/albums/v43/Luigi/Choplifter%203/SPAAV.png --Arima (talk) 23:37, 5 December 2011 (UTC)


 * Presumably it's supposed to be a Self-propelled anti-aircraft weapon. Mikenorton (talk) 23:44, 5 December 2011 (UTC)


 * Didn't you ask the same ol' question a few days ago? 67.169.177.176 (talk) 23:52, 5 December 2011 (UTC)
 * WP:Reference desk/Archives/Science/2011 November 30. -- 203.82.66.201 (talk) 00:05, 6 December 2011 (UTC)
 * Technically speaking, that question was NOT answered because no one gave the exact Military Designation of the vehicle. --Arima (talk) 09:25, 7 December 2011 (UTC)
 * Itinerant has given you the military designation last time -- Self-Propelled Anti-Aircraft Vehicle. What more do you want? 67.169.177.176 (talk) 07:44, 8 December 2011 (UTC)


 * It doesn't appear to represent any particular model. I'd describe it as a tank modified to carry a four-barreled anti-aircraft turret, something that was quite popular in mid to late World War II. --Carnildo (talk) 02:57, 9 December 2011 (UTC)
 * Hm. Can anyone at least identify the Turret? --Arima (talk) 04:55, 9 December 2011 (UTC)


 * Oh, THAT'S what you wanted -- why didn't you say so the first time? In this case, there's no way to be absolutely sure, but it looks to me like either a Chinese Type 95 or its elder cousin the ubiquitous Russian ZSU-23. 67.169.177.176 (talk) 06:40, 9 December 2011 (UTC)