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November 28

Bathing

100 years ago people bathed anywhere from once a month to once a year. 200-300 years ago it was once a year. Have there been any studies done on bathing frequency and skin infection (staph infection, boils, fungal infection ect) and also UTI's. Most people bath 1-7 times a week now and I'm curious if skin infection and UTI's have gone down or remain the same. --Wrk678 (talk) 06:31, 28 November 2012 (UTC)

I don't think you can generalize on bathing frequency like that. In tropical areas on the beach, people probably bathed far more often than in cold climates inland, due to the difficulty of obtaining and heating the necessary water. Then there were those who didn't bathe because they thought it unhealthy, which it was, if they didn't have the sense to keep warm until they dried off. Also, lye soap can be rough on the skin, if used daily. StuRat (talk) 06:40, 28 November 2012 (UTC)

It also depends a lot on place. During the Roman Empire, people frequented the Thermae several times per week. --Jayron32 06:53, 28 November 2012 (UTC)

Nearly always, if you go to the doctor and tell him about some skin rash you've got, unless it is certain specific diseases, he'll tell you to stop using normal soap and instead use a bag of oats or some dermatitis "soap" that isn't actually soap. And quite often the rash will then clear up, or at least get better. Trouble is, without soap, you don't feel clean, and you smell a bit. Also, in hot climates (eg Australia), a daily wash with soap seems to help you keep cool and not sweat so much. Ratbone 58.169.233.62 (talk) 07:54, 28 November 2012 (UTC)

What's so unhealthy about being cold? I hope you're not referring to this unfortunate misconception. Evanh2008 ^{(talk|contribs)} 09:57, 28 November 2012 (UTC)

Your link doesn't say it's a misconception. Dry, cold air leads to cracked, chapped lips and an irritated throat and nasal passages, both of which allow viruses in. The rest of your body is normally protected, being covered with clothes and oil, but, after a bath, you have neither, if you used lye soap and no moisturizer. StuRat (talk) 23:57, 28 November 2012 (UTC)

Maybe, but if you are low on calories (most people would be 200 years ago or earlier) cooling off your body in winter is a bad idea for your health in general, because calories will be used to rewarm it, intead of being invested in building up your imune system. Any germ can take advantage of a slightly weaker imune system. --Lgriot (talk) 10:13, 28 November 2012 (UTC)

Do you have a reference for most people being malnourished 200 years ago? That's the early days of the industrial revolution in Europe, so the vast majority of people were still living in the country (even more so outside Europe). My understanding is that most people grew their own food so, except in bad years, would have eaten pretty good diets. It was only after moving the cities that food became a significant problem. --Tango (talk) 01:22, 1 December 2012 (UTC)

can anyone answer my original question? In the usa 100 years ago on the east coast they didnt bathe much. --Wrk678 (talk) 23:51, 28 November 2012 (UTC)

I doubt anyone can answer your question for the simple reason that information about the frequency of skin infections and urinary tract infections occurring 200 ago is not widely available (if available at all). Richard Avery (talk) 08:23, 29 November 2012 (UTC)

Lots of US families a hundred years ago had the Saturday night bath as a standard. I question the OPs assertion that they only bathed once a month back then. Maybe people who liked being filthy, or those who vnever did enough work to get dirt on their bodies. 75.34.30.62 (talk) 20:02, 29 November 2012 (UTC)

Or those who lived in places where water was very scarce. 24.23.196.85 (talk) 09:18, 30 November 2012 (UTC)

The vast majority of US settlers wee clever enough to live where there was water a hundred years ago. 75.34.30.62 (talk) 20:48, 1 December 2012 (UTC)

Fluoroauric acid

As gold(V) fluoride is a stronger fluoride accepter than antimony pentafluoride, I'd imagine it would create a stronger acid than fluoroantimonic acid based purely on fluoride affinity if mixed with hydrogen fluoride (as with fluoroantimonic acid). Am I right, or are there other factors affecting the strength of such an acid?--Jasper Deng (talk) 06:55, 28 November 2012 (UTC)

Variants of this have been asked several times over the past year or two. Executive summary has been IIRC "no matter what you think, you're missing something (or something isn't fully known period) if you think you're making something stronger than fluoroantimonic". Likely places to search are the archive of WP:RD/S, the talkpage of the acid, and maybe my talk-page.DMacks (talk) 07:06, 28 November 2012 (UTC)

From :

It can therefore be assumed HF/AuF₅ solutions are stronger Bronstedt acids than the so far strongest acid HF/SbF₅. But the extreme acidity of such HF/AuF₅ solutions is also the reason why AuF₅ dissolved in HF decomposes to AuF₃ and F₂. It is well known that the highest oxidation states are destabilized in acidic solutions. Were it not such an unstable system, HF/AuF₅ could be used for protonation reactions that are otherwise not even possible with HF/SbF₅.

If you want a copy of the paper, let me know on my talk page and I can e-mail it to you. Buddy431 (talk) 03:35, 2 December 2012 (UTC)

Did Carl Sagan know the intended use of his calculations and still willingly participate?

From this story: "According to the report in The Sun, the US would have used an atom bomb, because a hydrogen bomb would have been too heavy. The planning reportedly included calculations by astronomer Carl Sagan, who was then a young graduate." 20.137.2.50 (talk) 15:02, 28 November 2012 (UTC)

The author of one of Sagan's biographies suggested that he may have committed a security breach in 1959 after revealing the classified project in an academic fellowship application. Reiffel concurred. Read Project_A119#Consequences Trio The Punch (talk) 15:15, 28 November 2012 (UTC)

He certainly knew about it, and he willingly participated. It's one of those ideas that seems silly or crazy in retrospect, but from a scientific standpoint, a nuclear blast would not have done much more to the moon than creating another crater. The craziest part of the project is the idea that the American people — much less American allies internationally — would have considering testing nuclear weapons on the moon to be a positive public relations stunt. --Mr.98 (talk) 15:51, 28 November 2012 (UTC)

I have to agree with Mr.98. Those crazy American people should have known bombing a little country no one likes would have been a much better idea than exploding a device on the moon, where it would harm no one (what's the point in not harming anyone?) and where everyone could actually see what they were up to! μηδείς (talk) 17:25, 28 November 2012 (UTC)

It would certainly show how powerful the US was, without contaminating the Earth. This seems a good way of working on your self-marketing during the cold war. I don't see anything crazy here. OsmanRF34 (talk) 18:58, 28 November 2012 (UTC)

Mr98 says "from a scientific standpoint, a nuclear blast would not have done much more to the moon than creating another crater." But our article says

Another factor [in the cancellation of the project], cited by project leader Leonard Reiffel, was the possible implications of the nuclear fallout for future lunar research projects and colonization.

Duoduoduo (talk) 18:52, 28 November 2012 (UTC)

Umm... what fallout? There's something known as solar wind which would very quickly sweep all fallout off the Moon and into deep space. The only radioactive material left on the surface of the Moon would be the debris welded into the Moon's surface by the heat of the blast, and even that would be slowly broken up by continual bombardment by meteoroids of all sizes and itself swept off the Moon by the solar wind. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 20:51, 28 November 2012 (UTC)

Haha, the solar wind is not that strong, man! The moon is covered in dust. I agree the issue would be of no concern at all because the moon is huge and you'd ask scientists where they were least likely to go for the next few years, because cosmic rays would be worse than the radioactivity, and for a host of other reasons. But the solar wind doesn't sweep the moon clean. μηδείς (talk) 20:58, 28 November 2012 (UTC)

Every sample of lunar soil and ice will be contaminated from that point on. We could possibly never find out the exact process of lunar formation thanks to that. Consider how it's no longer possible to manufacture steel that's free from Cobalt-60 contaminants on Earth.Dncsky (talk) 21:28, 28 November 2012 (UTC)

Yes it is - just make steel without cobalt. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 22:27, 28 November 2012 (UTC)

If it were that easy we wouldn't be digging up battleships for steel.Dncsky (talk) 22:47, 28 November 2012 (UTC)

The escape velocity on the moon is 2.4 km/s (5400 miles / hr), and the local gravity is 1.6 m/s². A substantial fraction of the dust and rock fragments kicked up by a nuclear explosion on the moon will fall back onto the moon. I'm not sure where you get the idea that the solar wind would scour the moon, but for anything heavier than gas molecules it is basically not true. The solar wind moves ~400 km/s but has a density of only about 6 protons / cm³ at the Earth's orbit. That implies a solar wind pressure of around 10^-9 Pascals. Unless an object has an extremely low mass in relation to its cross-sectional area, the force imparted by solar wind bombardment won't be large enough to move it away from the moon's gravity. Dust particles on the moon can't be dislodged by the solar wind. Dragons flight (talk) 21:20, 28 November 2012 (UTC)

Practically all of the radiation which is not welded into the Moon's surface would be atomised gas. Unlike on Earth, there is zilch blast wave to generate dust, so anything which is not directly vaporised by the radiation from the detonation would stay firmly attached to the Moon's surface. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 22:27, 28 November 2012 (UTC)

If it is at the surface of the moon, the mere act of vaporizing rock will create a blast wave and excavate a crater. It may be smaller than on Earth, but it wouldn't be inconsequential. They could diminish the effects by placing the explosion well above the surface, but if you just wanted to set off a bomb in space then why carry it all the way to the moon? Dragons flight (talk) 22:51, 28 November 2012 (UTC)

I can see the contamination being an issue from a scientific standpoint — it could make it hard to do certain types of future measurements on lunar soil, and this is from a pre-Apollo understanding of the lunar surface anyway. I wasn't trying to imply it was a good idea, just that the "blow up the moon" stuff is a bit hyperbolic. It's an awful idea from a P.R. standpoint, as the attention given to this (decades old) story makes somewhat clear: people have at best mixed feelings about setting off nukes anyway, but to do it to something as timeless, visible, and apparently "pristine" as the moon ought to have been an absolute no-go. (I wonder how people would feel, incidentally, if they knew that we left several small plutonium power generators on the moon as a result of Apollo...) --Mr.98 (talk) 23:44, 28 November 2012 (UTC)

My question is not about any of the technicalities of the consequences of trying to blow up the moon, but how in the hell a man like Carl Sagan, who seemingly placed great value on natural celestial objects and not destroying them, was convinced to contribute to the project. 67.163.109.173 (talk) 22:23, 28 November 2012 (UTC)

That amounts to a request for speculation and opinion. Unless on the off chance he explained himself, say in The Collected Letters of Carl Sagan, we can't help you with that, we do not make windows into men's souls here. μηδείς (talk) 22:54, 28 November 2012 (UTC)

Of course I'm only interested in what he himself said of it. "Off chance"? Seems like something people would definitely have asked him or pressed his response on if it came to light before he died. 67.163.109.173 (talk) 23:12, 28 November 2012 (UTC)

Based on the information in Project A119, it would appear that the project was mostly secret until after Carl Sagan's death. Dragons flight (talk) 00:07, 29 November 2012 (UTC)

The ostensible goal of the project, aside from the P.R. aspects, were to find out more about the constituents parts of the moon. They wouldn't really "blow up the moon" — that's just journalistic hyperbole. For a comparable sort of thing, see also Operation Argus. --Mr.98 (talk) 23:39, 28 November 2012 (UTC)

The OP seems to be starting with the premise that nuclear devices are inherently evil (the Evilonium-235, no doubt) and that any use of them is therefor unimaginable. But many scientists supported notions like Project Orion in principle. And if a demonstration of the destructive power of the bomb were visible worldwide, not to mention would give plenty of scientific data, is it impossible that a man like Sagan might consider the possible experiment? Questions framed in the form of "how in the hell" seem to imply a very strong desire to engage in soapboxing, rather than research. μηδείς (talk) 01:56, 29 November 2012 (UTC)

If you or others transfer the blowing up of the moon part to the journalists or append obtained knowledge about the true state of mind of the project runners that they meant "but not really blow it up, just scare 'em" (just talking desired intent, not at all thinking the ability were ever there) then I retract my soapbox-impression-inducing use of "hell." 67.163.109.173 (talk) 02:18, 29 November 2012 (UTC)

Okay, hehe. I thought it was obvious the notion was not actually to blow up (think Death Star) the moon. 03:18, 29 November 2012 (UTC)

Yes when I first saw this question and saw the article, I thought what the hell, there's no way they seriously thought they could blow up the moon, and a few quick searches as well as a look at our article confirmed that the never the intention or belief but simply journalistic hyperbole (present in too many sources). But the fact they couldn't do so seemed obvious enough and the OP themselves didn't comment on this point so I decided there was no point commenting. Nil Einne (talk) 12:55, 2 December 2012 (UTC)

It's worth remembering a fair bit of Carl Sagan's fame and quite a few of his writings came later in his life. People's opinions of things often change over time and they may not even always remember the change in their opinions. In other words, even if it's true the personality you understood Carl Sagan had from his writings, interviews, television shows etc, would not have liked the concept, and even if your understanding isn't that far off the mark from Carl Sagan's real personality at some point in his life (perhaps a melding over time), it doesn't necessarily mean he would always have felt that way. In fact, this project is probably a decent example of that. I suspect if you ever ask any people involved who are still living, most would say it was a dumb idea even though obviously a fair few did not think this at the time. Nil Einne (talk) 15:11, 29 November 2012 (UTC)

Harold White / NASA research on warp drive

Going off of this article here -- so I'm not a scientist by any stretch of the means, and most of the stuff in the Alcubierre drive article makes my head hurt. Main thing is - even if White did legitimately find a way to reduce the energy requirements - doesn't this still all depend on the existence of the same theoretical exotic matter Alcubierre's original idea talked about? If that's the case, what are White and his people at NASA even researching? --Brasswatchman (talk) 16:41, 28 November 2012 (UTC)

NASA is a huge organization; it directly and indirectly supports an absolutely vast amount of research. Here's a very useful and informative website maintained by NASA's Glenn Research Center: Warp Drive, When?. It provides links to numerous research avenues that have been explored, and helps explain in plain language exactly why this problem is so difficult. I find that NASA web-page far more insightful than most pop-science publications on the topic. And, for the enthusiastic reader, there are links to more technical research papers. The NASA "Breakthrough Propulsion Physics" laboratory is also very helpful if you're not familiar with the topic. You might find this summary enlightening, as well: All NASA support to sustain cognizance on these possibilities has been withdrawn as of October 1, 2008.[1] In other words, it is the official position of the current administration that this research does not warrant NASA support: irrespective of whether the physics is interesting or impossible or even completely legitimate, the expected returns on the investment of time, talent, and money, are not seen as particularly worthwhile. Nimur (talk) 17:31, 28 November 2012 (UTC)

Thanks for the idea of searching at NASA - can't believe I didn't think of that. Wound up finding these papers, if anyone is curious: Warp Field Mechanics 101 and Eagleworks Laboratories: Advanced Propulsion Physics Research. It looks like White and his team are specifically focusing on trying to measure the expansion of spacetime to see if they can measure any possible preexisting "warps" -- which I suppose would be a precursor for trying to hunt down any kind of the exotic matter Alcubierre's ideas require. Scanning the papers, I get the impression that White and his cohorts may perhaps be motivated more by enthusiasm and a certain amount of optimism rather than solid experimental fact... still, I suppose this is something that's worth looking into, just in case. --Brasswatchman (talk) 19:03, 29 November 2012 (UTC)

It may be worth looking into but not by these guys, who are pretty clueless. In the second document they talk about a "quantum vacuum plasma thruster", which is apparently a reactionless drive that pushes against vacuum fluctuations. They think not only that this is possible but that models have actually been built and work, and they seem to think there's nothing controversial about the concept. I conclude from this that they've never talked to a real particle physicist. -- BenRG (talk) 06:39, 30 November 2012 (UTC)

Yes, it still needs exotic matter. I don't know how White used/uses his grant money, but according to the article one thing he did was build a modified Michelson–Morley interferometer and a ring of ceramic capacitors. Don't ask me why. -- BenRG (talk) 17:47, 29 November 2012 (UTC)

Size of bubbles in weightlessness

What determines the size of bubbles in weightlessness and do all liquids have the same bubble diameter in weightlessness? Thanks--93.174.25.12 (talk) 20:36, 28 November 2012 (UTC)

Surface tension determines the size of bubbles. As not all liquids have the same surface tension, different liquids have different bubble diameters even in weightlessness. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 20:45, 28 November 2012 (UTC)

Unless you are saying that density actually varies in weightlessness, Whoop, all that matters is volume, i.e., mass divided by density. Surface tension holds the bubble together and makes it tend toward spherical shape when not perturbed or sticking to something else. But surface tension is not affected by gravity. μηδείς (talk) 20:55, 28 November 2012 (UTC)

Yes, that is why gravity or lack thereof does not and cannot make different kinds of liquid have the same sizes of bubble. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 21:05, 28 November 2012 (UTC)

Moving this down to first indent for clarity: per Medeis, volume is a function of mass and density, and the basic sizes are unchanged between microgravity and any Earthbound laboratory. If liquid A fills less of a beaker than liquid B here on Earth, it will likewise form a smaller blob in space (assuming otherwise equal conditions like temperature and pressure). — Lomn 21:29, 28 November 2012 (UTC)

Now, for the counterpoint: if you're instead asking "how big of an air bubble can I create within a blob of liquid in microgravity?" then yes, surface tension is a significant factor. Again, you'll observe a basic correlation between behavior on Earth and behavior in space, though I would expect a substantial scaling factor. You might also have to quibble over definitions of what constitutes "a bubble of air within a blob of liquid". — Lomn 21:36, 28 November 2012 (UTC)

That would make sense of Whoop's statements--although gravity would still not matter, and only certain mixtures will allow you to make air bubbles. μηδείς (talk) 22:48, 28 November 2012 (UTC)

Cooling of Air-cooled engines

I'm trying to track down the original source of this claim from Air-cooled_engine: "In all combustion engines, a great percentage of the heat generated (around 44%) escapes through the exhaust, not through either a liquid cooling system nor through the metal fins of an air-cooled engine (12%). About 8% of the heat energy finds its way into the oil, which although primarily meant for lubrication, also plays a role in heat dissipation via a cooler.". The given source [2] does not contain any references. I'm interested in the breakdown of the remaining 36% of the waste heat.

Googling "engine heat 44% 12% 8%"[3] only produces sites with a verbatim copy of the erroneous quote from WP.

Alternatively if anyone knows where I can similar figures like this that would be great too; basically any ballpark break-down of how much waste heat is exhausted via each route in an ICE.Dncsky (talk) 21:17, 28 November 2012 (UTC)

I notice that only adds up to 64%. I wonder where the remaining 36% goes. Radiating off the rest of the engine block and heating the passenger compartment when the heat is on ? In any case, those numbers don't seem that unreasonable, to me. StuRat (talk) 00:10, 29 November 2012 (UTC)

The left over 36% is the mechanical power output to the pistons. Radiation of the engine surfaces is much much lower. Ratbone 124.178.55.2 (talk) 16:40, 29 November 2012 (UTC)

Have a llook in Heywood "Internal Combustion Engine" Greglocock (talk) 00:19, 29 November 2012 (UTC)

You, sir, are a Godsend. Page 675[4] had exactly what I was looking for. Do you have a script that checks this page for engine related questions or something? ;)Dncsky (talk) 00:42, 29 November 2012 (UTC)

For a good discussion, with typical values, in an easy to read format (without math or proof), of where the fuel energy goes, see later editions of Harry Ricardo's classic The Hight Speed Internal Combustion Engine (Blackie pub). A very good treatment, theory and data, is Charles Fayette Taylor's 1960's era textbook. The amount of heat lost in the exhaust is easily calculated approximately by applying the otto formula, with some corrections for the finite combustion time and for dissociation, and the heat lost to the coolant. As the heat lost to coolant via cylinders and head is quite small, you need only make a rough approximation. (Note that the heat rejected to ambient by the radiator is considerably greater than the heat lost from combustion gasses within the cylinder, as it includes heat generated by friction and heat lost from exhaust gasses to the exhaust passages in the head and manifold. Plenty of measured data is available to support such approximation. Manufacturers data for sales and application purposes of industrial engines usually includes the fractions of fuel energy converted to mechanical output at the flywheel, heat lost to coolant, and heat lost to exhaust. There is always a gap between the total of the three and the energy value of the fuel, this gap being the heat lost from engine surfaces by radiation and convection, being typically (in large engines) about 5 to 8% of the engine maximum output fuel energy. Ratbone 121.221.30.167 (talk) 01:09, 29 November 2012 (UTC)

So, are the numbers in our article correct ? StuRat (talk) 01:49, 29 November 2012 (UTC)

I seem to remember answering a similar question from you on Ref Desk before. The numbers look roughly right. I don't have any measured data immediately to hand, and I'm not familiar with aircooled engines, however I have a computer software package that gives accurate (+,- 2%) calculations for large diesel engines (after you enter a large amount of engine physical measurements). For a typical large truck size engine, (15 litres, 4 valves per cyl, compression ratio 15:1): The data (naturally aspirated at full output, 1500 RPM) from this package is :-

Brake Power Output:........265 kW (39%)

Total Loss to Coolant:....164 kW (24%)

Loss to exhaust:..............233 kW (34%)

Loss from engine surfaces..19 kW ( 3%)

The sum of the heat lost to coolant and to air from engine surfaces (164 + 19 kW) is made up of:-

Cylinder wall loss to coolant/air:.........57 kW (includes combustion heat loss to oil via pistons)

Exhaust port loss to coolant/air..85 kW

Friction loss to coolant/air:.......41 kW

These figures look somewhat different to the data cited by the OP. However, it should be noted that : 1) diesel engines are substantially more eficient than gasoline engines, due to higher compression ratio, no air throttling, and lower combustion temperatures; 2) aircooled engines are most commonly small engines, so the surface area compared to power is relatively high. So the data cited by the OP is not unreasonable.

This of course is something you have to take on trust, as you don't have my software, but you can check in C F Taylor's book. Ratbone 121.221.30.167 (talk) 02:53, 29 November 2012 (UTC)

The first number is how much energy is used, not excess heat, which is what we're discussing here. The total energy produced by an engine, of course, being mechanical, heat, exhaust pressure, and a tiny bit as sound and engine wear. The "loss to exhaust" might include both heat and pressure. StuRat (talk) 03:11, 29 November 2012 (UTC)

I can't see what you are trying to say, Stu - your first sentence is too cryptic. The OP said 44% (of the combustion heat) is lost to exhaust, compared to my calculated estimete of 34%. The discepancy is accounted for by the higher thermodymanic efficiency of the diesel engine used in my example, as I said. The figure "Loss to exhaust" in both cases is the energy lost out the exhaust pipe - yes, this lost energy is manifested in the temperature (most of the energy) and pressure (some of the energy) of the exhaust gasses, both temp and press being above that of the ambient air. For the 15 litre diesel example, the acoustic power generated from engine surfaces is of the order of a few tens of watts at most and is always ignored in engine thermodynamic efficiency calculations. If this surprises you, consider a domestic stereo system - typical electrical output 50 W RMS per channel, Loudspeaker efficiency 3%, music mean to peak ratio 0.1, mean acoustic power output 150 milliwatt. And, while it's not like a big engine in full cry, you can certainly deafen people with a stereo. Most of the acoustic energy comes from the exhaust, which is already accounted for. In theory, the wearing of bearing surfaces represents an energy loss. However, the energy lost in this way, which can be calculated by the science of tribology, is really minute, and nobody would bother. In any case, it is already accounted for in the figure for friction loss. Ratbone 121.221.7.194 (talk) 03:52, 29 November 2012 (UTC)

My interpretation of the OP is that it asked what percentage of the waste heat was dissipated by various means. That is, he is excluding the actual work done by the engine by the moving cylinders. Thus, the percentage of waste heat going to the exhaust is 44%, but the percentage of the total energy going to the exhaust would be less. StuRat (talk) 04:01, 29 November 2012 (UTC)

Well, only the OP can really say what he had in mind, however he /she accurately quoted from the Wikipedia article. The OP and the article says "..percentage of heat generated..", not percentage of waste heat generated - so the article is talking about the combustion heat, not the waste heat. The article could have been better worded, but the meaning is never the less clear - to an engine man at any rate. However, the OP used the phrase "waste heat" in the last sentence of his question, and that implies he misunderstood the data. Using the waste heat as a base, for my example above, the figures are:-

Combustion heat:........686 kW

Brake power output:....265 kW

"Wasted heat" is 686 - 265 = 421 kW

Exhaust heat:............233 kW i.e., 55% of wasted heat. (34% of combustion heat as given in my previous post)

55% is not 34% and for a typical air cooled gasoline engine the descrepancy will be about as bad. I can't think why you would want to calculate in this way. In any case, the reference for the Wiki article on this aspect, http://www.avweb.com/news/maint/182883-1.html, makes it very clear they meant 44% of the combustion heat, not the wasted heat. The answer to the OP's question, "where does the remaining 36% go", is of course the indicated power output (the mechanical effort to the pistons). Most of this ends up as the mechanical (i.e., brake) power output (typically about 25% of the total heat in an ordinary gasoline engine), the rest is lost in bearing and piston ring friction, valve gear and oil pumping loses. Ratbone 121.215.61.79 (talk) 12:26, 29 November 2012 (UTC)

November 29

Where do drug names come from?

Back in August I had a minor heart attack, and was prescribed an anticoagulant drug called Ticagrelor. Apparently it's an updated version of something called Clopidogrel. I'm also prescribed Ramipril and Bisoprolol. I'm just wondering where these names come from.

I know there are IUPAC names (Ticagelor is, God help us, (1S,2S,3R,5S)-3-[7-[(1R,2S)-2-(3,4-Difluorophenyl)cyclopropylamino]-5-(propylthio)- 3H-[1,2,3]triazolo[4,5-d]pyrimidin-3-yl]-5-(2-hydroxyethoxy)cyclopentane-1,2-diol, for instance) and trade names (ticagrelor is "Brilique" in some parts of the world), but why ticagrelor? Why not boffinokpum or gluponifen? Why four syllables? Why is ticagrelor not called "numptum" or "bonktyrumptimbul"?

I'm aware that some drug families have similar names (-pril indicates ACE inhibitor and -olol means Beta blocker) but why (for instance) "bisoprolol" rather than "bogolol", why "ramipril" rather than "nobbipril"?

Same goes for statins. They seem to have names (and again, I'm not talking trade names like "Lipitor") of the form thingvastatin, such as Atorvastatin (ironic, given its similarity to Atora), Simvastatin and Lovastatin.

I can see why systematic names such as IUPAC designations are assigned, trade names come from some completely barmy marketing outfit (and I'd like to meet the chap who decided that "Brilique" was just such a super name for a platelet inhibitor to be prescribed following heart attacks) but where do half-way houses, neither systematic nor marketing, such as "ticagrelor" come from? Tonywalton ^Talk 00:12, 29 November 2012 (UTC)

The only rules (in the US) are officially described here. If it doesn't break a rule, they can call it whatever the hell they want. Someguy1221 (talk) 00:33, 29 November 2012 (UTC)

International Nonproprietary Name. DMacks (talk) 01:47, 29 November 2012 (UTC)

• There are lots of different considerations. First there's the difference between the chemical itself and the brand name it's marketed under. Minoxidil, 6-piperidin-1-ylpyrimidine-2,4-diamine 3-oxide, is the active ingredient of Rogaine. The chemical name is ultimately arbitrary, but suggests diamine oxide, with the NO group suspected of being the active site. The name Rogaine was originally suggested as Regaine, for obvious reasons, but was rejected by regulators as too suggestive. Atorvastatin, the chemical in the brand Lipitor, is a statin class drug with cardiovascular benefits. 'Lipitor' is obviously something powerful (think "terminator") that has to do with fighting lipids.

Beyond such associations, drug companies don't want to pick a name that is offensive or has bad connotations in other languages, such as the case of the Chevy Itdoesn'tgo. They want the name to be different enough from other names that the two are not confused, but not so different that it is hard to pronounce or remember. People have been killed by drug name confusions, see the ref below. Names with C, P, V, X, and Z are popular, frankly because they sound powerful and a little magical. Our article Brand name didn't lead anywhere useful, but this very good article gives all the basics: http://www.medicinenet.com/script/main/art.asp?articlekey=53208. Sometimes I have fun with the pharmacist, and ask if they filled my prescription for fratastatin, or generic dammitol. But I wouldn't do something like that if she were busy or we weren't on a first name basis. μηδείς (talk) 01:48, 29 November 2012 (UTC)

You mean Chevy Nova#Urban legend? Nil Einne (talk) 11:45, 29 November 2012 (UTC)

Yes. I assumed the main article would link to it, but thanks for the direct link. I should also mention there have been many deaths linked to accidental dispensation of a drug confused with the one actually prescribed due to similarities in names. The medicinenet link I gave above documents some. μηδείς (talk) 16:37, 29 November 2012 (UTC)

Oh, I did mention it. Forgot to take my GleeMONEX. μηδείς (talk) 21:29, 29 November 2012 (UTC)

I think you (or possibly I) have missed the point. I am not talking about trade names like "Brilique". This is the registered trade name for (see IUPAC name above). Trade names can be anything.

I'm wondering about is why it's also called "ticagrelor". Why, come to that, is 3-piperidin (and so on) called "Minoxidil". Why not "Boggyplonk"? There would appear to be three names to any given (prescription) drug. A IUPAC name which is, far from what μηδείς suggests, particularly exact, not "arbitrary". The chemical name is an exact description of the compound. Then there is a name whose nature this question is trying to ascertain (such as Ticagrelor or Clopidogrel). Then, finally. there is a trade name such as Brliique or Plavix. Why three, and what generates the "non trade" name? Tonywalton ^Talk 23:56, 29 November 2012 (UTC)

I seem to have been misunderstood. By chemical name I meant the one assigned to the item patented, not the IUPAC formula. I referred to minoxidil as the chemical name above which suggests the amine and oxide of the IUPAC formula. That one is indeed arbitrary within the obvious parameters of pronounceability and the ones I gave, a unique, memorable, non-offensive name that may suggest the class of drug, etc. The company that patents the drug names it, then usually markets it under a trademark name that is more customer than industry oriented. Both are made up. There are no set rules. It's no different than inventing something with specific dimensions, say a 10"-diameter pressed aluminum cake pan, patenting it under the industry name 10DPACP, and marketing it under the trademark name Frisbee. What you are calling the trade and non-trade names are the trademark and patent names. Both are used in trade. μηδείς (talk) 01:29, 30 November 2012 (UTC)

As I mentioned earlier (and others also stated in various ways), the generic drug-name, which you identify as the "non trade" name, is made up, but does follow some set patterns based on various biochemical and/or structural properties (as you also noted). The parts that are patterned follow published rules (INN, BAN, USAN, etc.), but the exact combination and details that are not part of the pattern rules are arbitrary (but tend to follow patterns again based on structure or activity). To answer one of your specific cases ("bisoprolol" rather than "bogolol"), bisoprolol appears to have two isopropyl groups and bi/bis is a common chemical prefix for "two". And "3–4 syllables" is one of the published standards (I'm sure the standards-bodies have reasons for making that declaration...ease of remembering and writing, I guess?). So if you say "we have this new beta-blocker that has as one of its distinguishing structural characteristics a 'bis-isopropyl'", contract that down to a two-syllable prefix for the '-olol' class. DMacks (talk) 04:59, 30 November 2012 (UTC)

Aha. Yes, I'd misunderstood your use of the term "chemical name", μηδείς. I can't see "clopidogrel" or "amlodipine" being "chemical names" in any meaningful sense, to be honest. "Generic name", fine. And there are published standards for these names, per DMacks, who also says they're sometimes contractions of a more precise chemical name (Ibuprofen is a good example of this, the name coming from iso-butyl-propanoic-phenolic acid). Thanks, all, for your contributions (but I still think "ticagrelor" sounds like one of Dr Who's more unpleasant foes). Tonywalton ^Talk 09:31, 30 November 2012 (UTC)

Yes, chemical name is obviously ambiguous. One thing that isn't clear is whether the various regulatory bodies actually propose generic names for newly approved drugs, or if the just approve those suggested by the patent holder as I asserted. See United States Adopted Name which DMacks mentions as USAN. That article also has a link to this excellent list of several hundred stems used in naming new medications], which is what I assume you have really been looking for. μηδείς (talk) 17:59, 30 November 2012 (UTC)

Generic names are proposed by the company/organization that files the New Drug Application (or equivalent in other jurisdictions). The name has to fit within the guidelines noted above, and then must be approved by the relevant regulatory agencies. -- Ed (Edgar181) 18:10, 30 November 2012 (UTC)

The Mechanism of Coldness and sore throat ?

what is happening in coldness (from feeling the right amount and time of cold, windy or not), and why our body's tend to develop sore throat (a very annoying situation) as for it. why not something else? — Preceding unsigned comment added by 79.182.153.70 (talk) 02:51, 29 November 2012 (UTC)

Cold air can't hold much humidity, and that dry air dries out the throat. Add to this the thermal shock of inhaling cold air, and damage is caused to the lining of the throat, making it sore and vulnerable to infection. StuRat (talk) 02:54, 29 November 2012 (UTC)

wow thanks ! enlightening.. ! what did you mean by "Lining" of the throat?, and why is soreness (redness?) accumulates infection?,, Blessings. 79.182.153.70 (talk) 04:25, 29 November 2012 (UTC)

The throat (both esophagus and trachea) are lined with mucus, which keeps them moist. This mucus provides a barrier to bacteria and viruses, since, in the time it would take for them to migrate through, they might be coughed up or swallowed and killed by stomach acid. We don't have skin inside, to protect the tissue, but this serves a similar function. Also, when we swallow things which would normally irritate the esophagus, like acidic sodas, the mucus keeps it away (the stomach lining also has mucus to protect it). When the mucus layer is reduced, then bacteria and viruses find it easier to infect our tissue, where they cause inflammation, apparent as redness and soreness. StuRat (talk) 06:49, 29 November 2012 (UTC)

There's another possibility. When it's cold, the temperature of the body surface can drop dramatically, and immune responses are slowed considerably in cold tissue. Looie496 (talk) 18:21, 29 November 2012 (UTC)

Which has to do with vasoconstriction in the extremities of the body. This happens especially when the person in question is not only cold but also wet, because the water takes away a huge amount of heat as it evaporates. 24.23.196.85 (talk) 09:24, 30 November 2012 (UTC)

Wouldn't low temps also reduce the activity level in the baddies ? StuRat (talk) 02:18, 3 December 2012 (UTC)

Computer in Matrix movies

I am currently writing a paper on virtual reality, and referencing Bishop George Berkeley's work on idealism and how his views today can be seen clearly exemplified in movies such as "The Matrix". I saw all three movies in the series when they came out. Now, I am wondering if the massive computer that keeps the Matrix in operation is, in the movie, itself conscious. Because if it is not, then it would mean that you need more than just enormous complexity to attain consciousness. This makes it a very different computer to the one in sci fi movie "The Thirteenth Floor", in which conscious entities exist but are not bound to bodies. They are, in that movie, fully conscious beings which exist as avatars of the computer in which they reside. This is a far more complex situation than the one in Matrix, I believe.

I myself do not agree with the strong AI position on this, as I think that while complexity is a necessary condition for consciousness, it is not a sufficient one. But then, I do not know what WOULD comprise such sufficient conditions. But I am not alone in this. As long as we don't know what makes us conscious, we cannot say with finality what conditions are necessary to achieve that state. And the "hard problem" of philosophy remains. Myles325a (talk) 06:04, 29 November 2012 (UTC)

I'm not sure what your question is, but if you're looking for resources, the "conscious computer" trope is a well tapped field for science fiction. Two that jump to mind as particularly notable and famous is "Mike" from Robert Heinlein's The Moon Is a Harsh Mistress and "HAL 9000" from the 2001: A Space Odyssey film, book, and various sequels thereof. The idea of consciousness being unbound from a body is also a well-used trope, the character of "The Dixie Flatline" from Neuromancer is a particularly seminal use of it. More recently, John Scalzi's Old Man's War makes use of the idea of mind transfer to transfer the consciousness from one body to another. If you're looking for the philosophical tradition that underpins the Big Questions regarding consciousness in general, Wikipedia's article consciousness is a good start, as is the Mind–body problem and if you want to get really nuts, dig into the Phenomenology philosophy of Husserl and Heidegger. --Jayron32 06:16, 29 November 2012 (UTC)

The Terminator (franchise) also comes to mind. StuRat (talk) 06:41, 29 November 2012 (UTC)

Sufficiently advanced computers may be indistinguishable from a human in their responses, but that doesn't automatically mean they are conscious. StuRat (talk) 06:41, 29 November 2012 (UTC)

If you can't 'distinguish' conciousness, what is it? AndyTheGrump (talk) 06:47, 29 November 2012 (UTC)

Well, then we get into philosophy, and the idea that I really don't know that anyone else in the universe in conscious. StuRat (talk) 06:51, 29 November 2012 (UTC)

See also p-zombie and hard problem of consciousness. --Trovatore (talk) 07:52, 29 November 2012 (UTC)

We don't have a good definition for consciousness. But imagine this thought experiment: Program a computer to simulate a bunch of neurons. This is clearly technologically possible for small-ish groups of neurons even now. A program/computer that did this would be dumb as rocks, certainly neither intelligent nor conscious. Now, suppose we could somehow scan a human brain, tracing every connection and measuring everything. That's difficult with present technology - but it doesn't seem to be impossible from a fundamental science standpoint. Now dump all of that data into our neuron simulator and start it running. If we have a sufficiently powerful computer to run all of that software in realtime - and if we connect the simulated brain to microphones and cameras via simulated ears and eyes - and to an audio jack via a simulated larynx - then what should happen is that the brain should behave pretty much exactly like the person you scanned. Every possible external test for consciousness would succeed. We ask the neural simulator "Are you conscious?" and it would reply "Yes!" - if you asked "Is it OK for me to shut down the software now?" and it would presumably reply "No!! Please don't kill me!"...and so forth. Should we say that this is "consciousness"? Notice that we didn't change the "dumb as rocks" software or the computer to do it - we just gave it more data. So is the consciousness somehow "contained" in that long stream of numbers? It's not a scientific question, it's a philosophical one.

That's one of the reasons why we don't have a good definition of "consciousness". SteveBaker (talk) 14:31, 29 November 2012 (UTC)

If we presume for argument's sake that we are conscious, then would it follow that animals are also? They would not say yes to the Q "are you conscious"165.212.189.187 (talk) 15:43, 29 November 2012 (UTC)

The question is whether consciousness is just piling on more connectivity or not. We really don't have a good sense as of yet how the human brain works except in the most basic terms. Going from a basic neurological description to a qualitative description of consciousness is still pretty far out there. I'd put our understanding of cognition in the single digits percentage-wise at this point (and I take that assessment from neurologists/cognitive scientists). Whether just simulating the neural wiring in and of itself will produce anything that acts like a human brain is still unclear to me; there's more than just wiring in there. There's still a lot of "scientific questions" there beyond the philosophical ones. I'm not saying its unanswerable — I think the consciousness must ultimately have a material basis, obviously, and presumably will yield to systematic analysis upon continued investigation — but I don't think we're really in a position to say, "oh, just pile on more complexity" and have that be compelling, yet. --Mr.98 (talk) 16:35, 29 November 2012 (UTC)

Too much thinking, overanalysis. "Consciousness" is simply "awareness of your own existence" on some level. ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:10, 29 November 2012 (UTC)

"Awareness"? "On some level"? What does that mean, precisely? Is my laptop "aware of its existence on some level"? (About This Mac --> I self-refer, therefore, I am?) The reason that philosophy spends so much of its time doing "too much thinking" is because flip answers yield no results upon attempts to actually use them for anything. Once you start trying to use said results to answer the questions people are actually interested in (much less the questions philosophers are interested in), you start having to refine them down, "overanalyze" them, "think too much". ("Physics" is simply "how the world works" on some level.) --Mr.98 (talk) 16:32, 29 November 2012 (UTC)

I agree: physics is simply "how the world works." But, consciousness is not a question of physics. The methods of physics (and, by extension, the other natural sciences) can be used to explore mechanisms that are related to consciousness, but it's really in the domain of philosophers to define what consciousness is - because natural sciences don't even attempt to answer that type of question. If you undertake a well-rounded study of the entire body of knowledge on the topic of consciousness will, of course, learn all sorts of things that we do know through physics (or bio-physics, or biology). We've learned incredible things about the way neurons operate; how they grow and interconnect; the neurochemists can explain how neurons signal, and neurologists can describe all that we've measured using the electroencephalograph. But none of these explorations have ever answered the question, "what is consciousness." That is not the way experimental science works; and for all that we learn about the mechanisms of our world, the scientific method never address the motives of the universe. So, natural science will never put the philosophers out of a job; for all we conclude about "how" the world works, we still need them to address the issue "why." Nimur (talk) 17:08, 29 November 2012 (UTC)

My point in invoking physics being "how the world works" is that such isn't a very useful definition of it if you actually want to do something with physics — if people had stopped there we wouldn't know very much. As for consciousness in general, I don't think consciousness is only a question of philosophy; I disagree that it is a "why" question. There is a hugely significant "how" question at the center of human cognition. Once we understand that better — how you go from a lump of cells to a seemingly unified awareness, one capable of generalizing inquiry to such a degree that it can even sit around asking itself why it thinks about itself so much — I think we'll have a much better understanding of what we physically mean by the term "consciousness." I find both the assertions that "we basically understand it, just scale up what we know about neurons" to be inadequate; I find the "don't think about it, it's just a problem for squishy philosophers" to be even more so. Fortunately there are plenty of people who are actually doing the work to try and figure out how the mind works out there. --Mr.98 (talk) 18:30, 29 November 2012 (UTC)

Modern Maccs are aware of their existence, That's why they started to call themselves iMac. OsmanRF34 (talk) 17:03, 29 November 2012 (UTC)

SteveBaker has almost the correct answer. If you just take into account that I can't be aware of the exact data in my head and consider how I should (in general) consider the abstract space defined by the possible data sets consistent with it representing me, then that's pretty much the answer. Count Iblis (talk) 21:01, 29 November 2012 (UTC)

That seems to lead to the conclusion that there are now, and always, Platonic abstractions that are not only conscious, but conscious of every possible quale. I find that — let's say unlikely. --Trovatore (talk) 10:24, 30 November 2012 (UTC)

• Consciousness is usually used to mean awareness of one's surroundings, like "regaining consciousness". What's being talked about above is usually called self-awareness, although Julian Jaynes, whom everyone should read (albeit with a shaker of salt), used consciousness in this latter sense. μηδείς (talk) 21:27, 29 November 2012 (UTC)

  Actually, what I find is that people often say self-awareness when they just mean awareness (in the sense of qualia — mechanical devices are "aware" of their surroundings in the sense that they have sensors capable of responding to them, but we rarely posit that they experience actual phenomena). I am not sure how the self- part snuck in there, because it's really not about a sense of self; it's just about a sense of anything, period. Phenomenal consciousness is another term that's better than self-awareness for the concept under discusson, and also illustrates the distinction with awareness of surroundings (for example, I am phenomenally conscious when dreaming, but not conscious of my physical surroundings). --Trovatore (talk) 19:08, 30 November 2012 (UTC)

  • "Awareness" is the common element there: of one's own existence and of one's surroundings. In short, "alive". Does a mechanical device such as a toaster, a car or a computer have an "awareness" of its surroundings? Yes, to the extent that it's been programmed to. But does it have awareness of its own existence? A sense of "self"? Maybe. But where's the evidence? Matrix is an interesting (while highly derivative) story. Have we been "programmed"? If so, by what? A computer? Natural evolution? God? Or all the above? ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:36, 30 November 2012 (UTC)

The latest news on AI seems to be this, from just up the road from my house. "Spaun can recognize numbers, remember lists and write them down. It even passes some basic aspects of an IQ test, the team reports in the journal Science." Matt Deres (talk) 16:48, 30 November 2012 (UTC)

The difficulty with consciousness is that we are not independent witnesses. If we were only allowed to use the evidence measurable with scientific instruments of the people around us - ignoring our own built-in biases completely - I think we could conclude that there is nothing special that human brains can do that couldn't be programmed into a highly complex and (presumably) non-conscious computer. Occams' razor would tell us that there is no such thing as consciousness. The HUGE problem with that conclusion is that each of us as individuals is seeing their own personal consciousness "from the inside". That (IMHO) is the only evidence that there is anything at all special going on here. We have no definition for what this "experience" is. We can only infer that people other than ourselves have this "thing" because they seem to say the same kinds of things about the experience as we do - and since we're all members of the same species, it seems likely that we're all more or less the same in this regard. So how could we possibly tell if some other animal or computer were to be conscious in the sense that we feel ourselves to be? Without a definition, or a way to quantify and measure it - it's kinda difficult to come up with any kind of science-based response. SteveBaker (talk) 19:01, 30 November 2012 (UTC)

Very true, which is exactly why the whole area of phenomena/qualia is so problematic for your "scientistic" world view, Steve. There are folks like Daniel Dennett who more or less explicitly reject the whole field for exactly this reason, and they can come up with very clever ways of framing this rejection, but it's still (IMO) a willful refusal to deal what's in front of their noses (or behind their noses, or in their noses, or you get the idea). We clearly are phenomenally conscious, and science's attempts at "explaining" this are all category errors. In my view they always will be, and this will remain a fundamental limitation on science. Don't get me wrong; I love science. But I don't think it can explain phenomenal consciousness. --Trovatore (talk) 19:39, 30 November 2012 (UTC)

I would be very suspicious of someone who did not believe that they themselves were conscious. It raises questions of their self-worth, self-respect, regard for the well-being of those around them, and ultimately trustworthiness and believability.165.212.189.187 (talk) 20:10, 30 November 2012 (UTC)

Denying one is conscious, has free will, or exists, or can be certain of anything, is a fashionable form of contrarian sophistry. Philosophical skepticism was encountered in ancient philosophy and is found today. (There was a Greek who would supposedly walk into ditches, doubting they were there. Doubting he ever existed, I won't name him.) It doesn't require that you argue convincingly in favor of anything, but allows a form of pseudo-sophistication, a way to claim you are on equal ground with people who actually do know things. For very smart people like Dennett, whom I have read and somewhat enjoy, this is often a game, or a complicated matter of definitions and tactical retreat when pushed. I can assure you that if you swing a punch at people who deny they are conscious, exist, etc., they will flinch and then get angry at you before they remember to laugh at themselves, if they do. μηδείς (talk) 21:48, 1 December 2012 (UTC)

The ultimate open minded skepticism about one's own existence is this tour de force by the Mad Revisionist. Gzuckier (talk) 04:16, 3 December 2012 (UTC)

Excipients and generics

When substituting a brand name for a generic drug, could it happen that the latter is less efficient due to a wrongly chose excipient? Are any real cases known? For what I understood, some substances are not easily absorbed unless they are mixed with another appropriate substance, so the excipient is also somehow part of the medicine (not just there to bulk up the real active medicine). OsmanRF34 (talk) 12:44, 29 November 2012 (UTC)

Our article on generic drugs notes that most regulatory regimes call for some test of measured bioequivalence to the brand name drug that they imitate. That article's footnotes will guide you to more specific criteria (which in any case will depend on the particular drug's route of administration, intended use, and so forth) but will almost always include things like measurement of the amount of active drug in the bloodstream at various times after administration. In the U.S., the FDA requires generics to pursue an Abbreviated New Drug Application prior to approval. TenOfAllTrades(talk) 13:22, 29 November 2012 (UTC)

Actually, there can be differences in absorption in certain circumstances/individuals, but also in delivery; for instance, although generic time release drugs are equivalent in the actual drug chemistry, the time release mechanism itself is likely still under patent and the generic might well use a totally different technology, which is not equivalent. Which brings us, serendipitiously, to the recent case of generic Wellbutrin 300 XL. Since the 150 mg time release generic had been tested and passed, the 300 mg version got accelerated approval; but post-marketing report gave evidence of frequent failure, which was reversed when the patients switched back to the brand name version, implicating failure of the time release technology for the 300 mg generic, though the point of failure is unknown, so the generics were pulled from the market. [5]. Gzuckier (talk) 03:50, 3 December 2012 (UTC)

electronic multivibrator repetion rate

i wish to build (for a modelling project) a DC circuit thst will alternately flash 2 lights. An integrated circuit called a 555 timer is capapble of doing this. The input for such device is an RC network, and I wish to have a repetition rate of about 0.3 to 0.5 Hz. at the output.

The MAIN question is how to calculate the proper input resistor/capacitor values in order to control (change) the repetition rate. A corollary question involves the output voltages. (I can utilize either 1.5, 9 or 12 voltlamp bulbs) Perhps I should ask an IC manufacturer/else consult an (unknown) application book. Thought that Wikipedia would be a good place to start. If I had an address, I could send a prliminary schematic of what I will be doing.

Thank you in advance for your assistance.

Edmund 71.200.89.43 (talk) 17:38, 29 November 2012 (UTC)

The 555 timer IC article has some equations regarding RC values and oscillator frequency, and also some specs about source/sink power. DMacks (talk) 19:11, 29 November 2012 (UTC)

You could try using LEDs as they draw way less power than a bulb.Staticd (talk) 18:31, 30 November 2012 (UTC)

Unidentified Bird in Neighbours

About a minute into today's Neighbours episode, there was a brief shot of a black and white bird on a chimney. Usually I don't have too much of a problem identifying the birds featured in the show, but this one has me stumped. One of the writers suggested that it might be a Magpie, but the shape of the head and the markings don't seem quite right to me. Did anyone catch the episode or can ID the bird from this blurry screenshot [6]? - JuneGloom Talk 21:02, 29 November 2012 (UTC)

I don't know - but it would be a good idea to ask over at Wikipedia talk:WikiProject Birds. The guys on there are really good at this - in fact, they spend much of their time identifying birds in photos. --Kurt Shaped Box (talk) 21:11, 29 November 2012 (UTC)

I live in the same state in Australia that Neighbours is filmed and other then the magpie, the other very common black and white bird here is the Magpie-lark, was it that? Vespine (talk) 21:24, 29 November 2012 (UTC)

I couldn't see the photo on my work computer, but I looked at your screen shot on my phone and I'm pretty sure it's the 3rd bird I would have guessed: a Grey Butcherbird, (not to be mistaken for Butcher Bird). The photos here looks more like your screenshot then the photos in our article. Vespine (talk) 21:43, 29 November 2012 (UTC)

I don't think it's a magpie, the beak is quite short, and looks hooked to me. That suggested a raptor, so I browsed List of birds of Australia... after also looking here [7], my best guess based on coloration is the Australian Hobby, perhaps a juvenile. It also seems to be about the right size (hard to get scale from the screenshot), and our article says the Hobby is common in urban parks. That being said, I have no specific expertise in this area, and might be way off :) SemanticMantis (talk) 21:51, 29 November 2012 (UTC)

After the Magpie suggestion, I did think Grey Butcherbird or maybe Pied Butcherbird. But their beaks appear to be too long. - JuneGloom Talk 22:28, 29 November 2012 (UTC)

Yes, my first impression was raptor and Semantic Mantis seems to have it. μηδείς (talk) 01:09, 30 November 2012 (UTC)

Ok, it's NOT a raptor. It's sitting on a house brick which has a length of 230mm, even a juvenile hobby is longer then that. My 4th guess: Willie Wagtail, fits the size, but i'm just not 100% sure about the white marking, it looks like it's coming just slightly up the shoulders, the only photos I can find of a wagtail it seems more of a distinctly chest patch...Vespine (talk) 03:07, 30 November 2012 (UTC)

It doesn't look like the wagtail, whose throat is black, and beak is different, it looks just like the hobby. And you can't judge the size given the tail is obscured and the bird's angle is foreshortened. μηδείς (talk) 04:30, 30 November 2012 (UTC)

In my estimation, this is not identifiable without further information. It is not Grallina, not Cracticus, not Gymnorhina. It is also not any sort of Wagtail. It is also not an immature Pycnonotus jocosus which has a visible white malar slash not evident here. The undertail is white, and this eliminates a whole lot of possibilities. The tail is also relatively long, and this eliminates the possibility of it being one of the black-headed races of Daphoenositta. It is, however, obviously a Passeriformes, and certainly not a Raptor. What can I not eliminate therefore? I can't eliminate, at least not on this poor photo, some sort of immature Myiagra though the head jizz seems wrong to me for that bird group. The bird appears to possess, however, an evident eye-ring even as bad as this photo is. I am also not sure that it might not be, as somebody mentioned above, one of the hooded races of Pycnonotus barbatus, perhaps an immature, perhaps an escape. Because of the eye-ring there might be another group that should be looked at, and that is somethng from Melithreptus though I can not discern here the peculiar whitish nucal half-collar usually associated with the genus even when juvenile. So, take it from one that has analysed bird photos for ID for almost thirty years, this is not identifiable with no further information, and from just this one bad photo. Anybody telling you that it is certainly this, or that, is just talking through his hat. Only possible ID's can come from this and based on pure conjecture.Steve Pryor (talk) 06:56, 30 November 2012 (UTC)

Well! We got told. :) Great reply, thank you.. Not a raptor:PVespine (talk) 07:15, 30 November 2012 (UTC)

Links to those species would be useful, this is the reference desk. Without that it's just alot of handwaving. μηδείς (talk) 17:36, 30 November 2012 (UTC)

Nobody here has claimed to provide a definitive answer, and I agree that a blurry photo is not enough to get a rigorous ID. In the spirit of edification, can you tell us why you rule out Raptors, and are so sure of Passiformes? Is it an overall "feel", or are there certain characteristics that you are using to key? I think many of us are genuinely interested in getting better at this sort of thing, and I for one would appreciate more detail from an expert. SemanticMantis (talk) 22:18, 30 November 2012 (UTC)

First, to Medeis. I came over and took a rather large amount of time to give an answer, at the request of somebody from the Reference Desk, and though I am certain that the Reference Desk has a certain agenda, it is not necessarily my purpose to further the interests of the Reference Desk. Therefore, hand-waving if you like!

SemanticMantis, I appreciate your tone, and I will respond. The reasons are that the bill is not discernible, so I have to infer from what I can see, and from what I know about possibly ranging Aussie raptors. The presence of an eye-ring, and the general shape of the head, were I to hypothesize a raptor of any sort it would by necessity and experience be some sort of Falco sp. (i.e., a Falcon). Several range here. However, here we have two problems, and they are that this bird presents a hooded appearance, a whitish belly, and from what can be seen of the undertail immediately inferior to the crissum (the crissum is the collective term for the zone of the vent (the cloaca) plus the undertail coverts) it can be seen to be whitish, and to be a clean white, that is not broken up by any sort of transverse barring. Of all the possibly ranging Falco sp, only the Nankeen Kestrel might in a pinch approximate this sort of undertail clean whiteness, however, this is obviously not a Nankeen Kestrel for other reasons, notably the blackish hooded caput (the head). All other ranging Falco species have either dark undertails, or visbly barred undertails, and this includes any possibly ranging Peregrine races (the only one that might approximate this sort of hooded appearance). Further, and before somebody suggests other possible raptors, Falco longipennis - Australian Hobby - are never whitish ventrally, even when immature, they are brownish, or russet, and they have visible darker belly streaking in all life phases, they also have "sideburns"; Falco hypoleucus - Grey Falcon - even with the bird in the photo not having a discernible bill we should see a yellowish blob here if this species because this species has an extensive yellow cere which extends into a concolourous yellow bill, plus this species has belly streaking, and the bird in the photos does not; Falco berigora (light morph) - Brown Falcon - this has brown culottes (i.e., tarsal feathering), it has a visible moustachial, and visible sideburns, plus the undertail is visible barred; Accipiter novaehollandiae - Grey Goshawk - both the grey morph, and the white morph have clean white undertails, however, neither has this hooded appearance; genus Elanus - two can range - axillaris (Black-shouldered Kite), and scriptus (Letter-winged Kite, both have whitish undertails. However, the adults have either pale grey crowns, or white crowns, and the immatures have brown pectoral zones which in axillaris is streaky, plus the immatures of both species have whitish faces delimited superiorly by brownish (not blackish) crowns.Steve Pryor (talk) 07:11, 1 December 2012 (UTC)

Well, Steve, since I think your answer is wrong, I guess you could just look on it as a bit of rejectable charity on my part to suggest that if you want readers actually to follow your suggestions you should take the time to type a few brackets and linkify them. μηδείς (talk) 17:44, 1 December 2012 (UTC)

Medeis, the Reference Desk is your bailiwick, not mine. I simply responded to a request from this Desk for an opinion and I have already dedicated considerable time doing so. I have absolutely no desire of making proselytes. However, if you wish to motivate an accurate rationale for what you feel is a raptor I will consider your argument and respond.Steve Pryor (talk) 17:52, 1 December 2012 (UTC)

I have no special authority here or on birds, although I do have some education in biology. What I am suggesting is that you look at Semantic Mantis's first response above where he provided links in his response to our articles on raptors, the birds of Australia, the Hobby, and an external article. Looking at the image of the Hobby in the link he provided seems to me rather conclusive evidence that is the bird (head shape, coloration, beak shape) unless there is a very close relative or a passerine so similar it would count as a mimic. But the identification's not my point. My point is that your very long and obviously effort-loaded response is very difficult to evaluate or use as a reference because you have not provided any links either to our own articles or to outside sources. What would be extremely helpful would be if you would go back and edit your response to WP:LINKIFY all the species and sources you have mentioned, such as Falco hypoleucus, for example, by putting paired square brackets around them in the edit box (e.g., [[Falco hypoleucus]]) so that when yo save the edited response these will show up as linked items. Then we can all (us and future reference desk readers) easily follow your arguments, see the evidence, and judge for ourselves. I would actually really like to read the articles on the items you have linked to, but searching myself, rather than clicking on standard links is prohibitively time consuming. Thanks. μηδείς (talk) 19:38, 1 December 2012 (UTC)

Medeis, excuse me if I have seemed rather curt with you. This is a question of how you and I view this particular subject (meaning this particular photo). For me, and I field hundreds of ID requests a year, this particular bad photo should never be the subject of anything other than passing interest, and certainly because of its not lending itself to any sort of definitive ID, in my view, it simply would never pass muster for being used as a reference for anything. It is simply not worth the hassle. If, in the future, somebody asks me from this desk to look at a bird photo for which it is possible to give a definitive ID, then I will be happy to provide explanatory links. This is, in this case, simply not possible. Anybody who is adept in the discernment of bird species from graphic media, photo, video, etc., will tell you that there is always a certain percentage of birds for which no definitive can be reached. The media is just not good enough, and the accompanying annecdotal information not helpful. Therefore, and I think you probably see my point in this case, it is a waste of time to attempt some sort of justification when any outcome can never be satisfactory because any possible result is just so conjectural.Steve Pryor (talk) 10:37, 2 December 2012 (UTC)

And that has what to do with adding links to your prior answer? μηδείς (talk) 16:50, 2 December 2012 (UTC)

Ugh, Med I think you're being an ass. It sounds like you're just bitter that the guy who came here and dedicated his time to help didn't agree with your naive guess. I for one also think it looks nothing like a raptor. You might want to check out our articles on confirmation bias and pareidolia. Maybe you're looking for features that confirm your belief and ignoring the evidence that contradicts it. Vespine (talk) 22:02, 2 December 2012 (UTC)

Well fuck you, Vespine. I don't necessarily disagree with Steve, I have just asked him to linkify his response so I can evaluate it. That you and he have a problem with this request strikes me as absurd, and that you continue to argue with and even insult me is bizarre in the extreme. Steven may be right, but he hasn't given us any way to determine that or not. μηδείς (talk) 22:08, 2 December 2012 (UTC)

Where did I insult you? Telling you I think you're being an ass is not actually an insult. Now I think you're being a major ass. Vespine (talk) 22:36, 2 December 2012 (UTC)

I'm by no means a bird expert, but after a quick look at the screenshot provided and a quick search, I came up with the Hooded Robin. Not 100% sure by any means, but it seems very close to me. douts (talk) 23:27, 2 December 2012 (UTC)

Man… if you are so interested, you can search the links for yourself

We are not paying him to work for us, so he don’t have the obligation of doing anything that, in fact, we can do

Instead you should give thanks to him for so an detailed and time consuming answer

And why start insulting people??!!Iskánder Vigoa Pérez (talk) 23:29, 2 December 2012 (UTC)

Who started insulting people? If I called you a bitter ass, would you find that normal ref desk behavior? I am quite happy with my own opinion, but was actually interested in cuckoo's. But I am not entitled to edit his contributions. My advice to him was good advice to all. He's wasting his time by posting here without providing links, and I don't find my friendly and repeated suggestion he do so problematic in the least. It's real a shame all his effort is wasted. μηδείς (talk) 02:02, 3 December 2012 (UTC)

I didn't call you a bitter ass, I said you were acting like an ass and that it came across like you were bitter about being wrong. Steve wrote three or four replies explaining what he thought in detail, instead of thanking him for his time, in a fairly blunt and ungrateful manner you tell him you think he's wrong and badger him for links. Which if you were interested you could easily look up for your self. He even explained that he was asked as a favour to come here to comment and is not usually a contributor to the ref desk, so linkifying things might not be something he could do easily or quickly, especially after the effort he has already put in. When several people tell you you're not being very gracious, you take it personally and crack the sads. I called it how I saw it, I think your behaviour was not very accommodating, I suggested you're seeing what you want to see (there is no way you can honestly say from the blurry blob that the bird has a hooked beak, for example) and I thought you were being an ass about it, which I actually think is a very mild jibe, I'm sorry it escalated that way. Vespine (talk) 02:43, 3 December 2012 (UTC)

Back on topic, it's a Common Myna - introduced and common as muck...it looks more clearly myna-like in the video than the photo.... :P Casliber (talk · contribs) 19:46, 3 December 2012 (UTC)

On line degree of medical science

I would like to learn and earn degree: Bachelor of medical science (with curses of biochemistry of course), but it's important for me that it will be from base (mainly in chemistry), and that all the degree I will learn OnLine. Where is it a website like this? 95.35.67.215 (talk) 23:22, 29 November 2012 (UTC)

Lots of on-line degree programs are not widely respected. If you think about taking one of them, I would strongly advise that you check with a variety of medical schools that you might subsequently apply to, to find out if they accept that degree from that particular on-line institution as a qualification for admission. Duoduoduo (talk) 16:53, 30 November 2012 (UTC)

I doubt a complete online accredited medical degree exits at all. You can make a descent bacherol in other science at some serious online college, but medicine no. Comploose (talk) 17:45, 30 November 2012 (UTC)

November 30

polywell

Can someone familiar with nuclear physics comment on whether polywell fusion reactors are actually feasible or not? To a laymen it sounds awfully lot like a free-energy device scam. There's been very little peer review on this since the research team is under a publishing embargo.Dncsky (talk) 00:56, 30 November 2012 (UTC)

It's not a free-energy device scam — fusion is real physics — but with all fusion programs there are three major hurdles: 1. Can it reach ignition? That is, can it generate more energy through the reactions than it takes to start the reactions? So far none of the methods pursued have done this, yet, with the exception of thermonuclear weapons. 2. Can it produce useful net energy? That is, can you get electricity out of it? This requires both considerable efficiency and also in some cases elaborate means of extracting the energy from the fusion reaction. 3. Can it produce economically viable net energy? That is, can a fusion plant be economically competitive with other fuels out there? Another big unknown. The rub is that as of yet, we're still trying to find a method that satisfies #1. NIF was supposed to do it; it hasn't so far and it's not clear that it ever will. ITER is supposed to do it, we'll see. Once someone has found a way to do #1, it should be relatively easy to figure out a way to scale it up for #2. As for #3, it really depends on technical constraints we don't know yet, as well as issues unrelated to fusion technology (e.g. the price of natural gas).

I'm not a fusion scientist but my read of the Polywell article suggests that the people working on it really think it will work, and that they have been able to convince other experts at funding agencies that it might work. I don't think it's a scam, but that doesn't mean it will actually work. The fusion quest is nothing if not a field of failed dreams. So far. --Mr.98 (talk) 03:25, 30 November 2012 (UTC)

I am familiar with the current state of fusion research and I support every cent behind the 10 billion spent on ITER. Regardless of whether it will eventually work that money still needs to be spent. I am asking because the only publication I can find on the polywell reactor [8] seems to have been discredited more than a decade ago[9][10]. Yet they are still receiving funding from the Navy. Dncsky (talk) 04:27, 30 November 2012 (UTC)

The "References" list in the article is quite long and includes lots of scientific publications. I guess I'm not understanding why you think there is not much information published on it. The article shows it going through many funding reviews, many publications, and so on. The Navy has given them a few million — not chump change, but not a huge amount by research standards. Again, I can't evaluate the technical merits, but I don't see anything here that's against the laws of physics. The question is just whether it'll work or not, and that's not an easy thing to answer usually without spending some money on it. --Mr.98 (talk) 14:08, 30 November 2012 (UTC)

The References list is quite long, but it doesn't include a whole lot of peer-reviewed publications; it's mostly an assortment of press clippings, contractor and company 'reports' of various types, and patents. Conceptually, 'polywell' devices are fairly well understood. Like their cousins, the Farnsworth fusors, they're able to confine and fuse small amounts of hot ions. In that respect, polywell devices are 'real' fusion devices that actually 'work'—unlike cold fusion setups, there's no question that fusor and polywell devices really do fuse hydrogen atoms. Also like the fusors, however, polywell devices aren't terribly efficient at it. The 'true believers' think it's possible to eventually engineer around the inefficiencies of the technique and create a workable energy source; most physicists remain (highly) skeptical.

The Navy has a history of being a sucker for pie-in-the-sky fusion research of all flavors; they're one of the few stable sources of funding for cold fusion research as well. TenOfAllTrades(talk) 20:24, 1 December 2012 (UTC)

What are the global\general\basic ingredients of sand "regular" earth?

(sorry for possible misterminology, i don't have basic knowledge in geology). thanks 79.182.153.70 (talk) 04:34, 30 November 2012 (UTC)

Sand regular earth? Are you talking about plain old Sand? As our article discusses, the chemical makeup of "sand" is highly variable, as it is defined based on its gross properties rather than its chemical composition. Our article gives some of the more common types of sand and what they are made of. Since you mentioned "earth", you might also be interested in soil. Someguy1221 (talk) 04:42, 30 November 2012 (UTC)

okey, it's becoming interesting. what do you mean by "it is defined based on its gross properties rather than its chemical composition". this sentence is very abstract to a layman like me. i ask what are the most basic and general and typical ingredients of sand (and soil) just like a little boy, a curious boy would ask about them, i rally am a total ignorant in this matter. you are doing an holy work by lifting me out of this mud of ignorance (nice example eh?). — Preceding unsigned comment added by 79.182.153.70 (talk) 06:59, 30 November 2012 (UTC)

In laymans terms, sand is pretty much any finely ground rock or mineral. If it looks like sand and it feels like sand, it's sand, no matter what it's really made of. In the same way wood is wood no matter what tree you cut it from. Someguy1221 (talk) 11:17, 30 November 2012 (UTC)

The most common material is quartz which would make a white sand. Also common are rock forming minerals such as feldspar and pyroxene. Other sand may be made from fragments of rock like basalt, or pieces of shell or coral. Black sand may contain ilmenite or particles or wood or charcoal or discoloured by iron sulfide. Graeme Bartlett (talk) 10:27, 30 November 2012 (UTC)

There is a nice table of the chemical composition of the Earth crust at Composition_of_the_Earth#Chemical_composition. The most abundant substances are silica, alumina, and lime, as far as I know all rock-forming materials (and hence possible sources for sand). --Stephan Schulz (talk) 12:27, 30 November 2012 (UTC)

Our article mentions quartz is common for sand in 'inland continental settings and non-tropical coastal settings'. It also mentions 'The bright white sands found in tropical and subtropical coastal settings are eroded limestone and may contain coral and shell fragments in addition to other organic or organically derived fragmental material'. There is a bit more useful info, I strongly suggest the OP read it if they haven't already. Nil Einne (talk) 13:47, 30 November 2012 (UTC)

As noted, 'sand' can be from just about any mineral that is ground by erosion and accumulates in one spot. I strongly recommend a visit to Hawaii to examine their...sand. In addition to 'white' sand (predominantly quartz, most common) you can find black sand (Punalu'u Beach, principally basalt), green sand (Papakolea Beach, colored by olivine), and red sand (Kaihalulu Bay, rich in iron compounds). TenOfAllTrades(talk) 13:50, 30 November 2012 (UTC)

Are you sure of the first statement? Haiwaii would generally be consider a tropical region and most sand there is likely to be coastal, and as I mentioned above (perhaps with an EC) our article suggests silica or quartz is actually often not the predominate material in white sand in such settings. [11] [12] [13] seem to agree that silica or quartz sand is not common in Haiwaii. Nil Einne (talk) 14:15, 30 November 2012 (UTC)

How about extremely small pebbles between X and Y mm diameter? Might it also help to identify what sand is not? EG: clay & soil, both with significantly more organic and fine powder-like material?165.212.189.187 (talk) 14:54, 30 November 2012 (UTC)

If the questioner goes to his neighborhood building center or hardware store and asks for "sand" for his child's sandbox, he is likely to get "play sand." This product has a Material Safety data Sheet which says it is made of "crystalline silica," which seems to be another name for silicon dioxide. It has been washed to reduce the dust and dirt. The other type of sand he would find in the store is "all purpose sand," which is darker and contains more dust. It is used for making concrete. Edison (talk) 15:50, 30 November 2012 (UTC)

Without NASA we wouldn't have computers

Someone told me this, is it correct? ScienceApe (talk) 18:08, 30 November 2012 (UTC)

No, computers were already around before NASA was even founded. See e.g. the Atanasoff–Berry Computer and ENIAC. - Lindert (talk) 18:18, 30 November 2012 (UTC)

On the general topic, I have read that entire industries have come out of the space program, because sending rocket ships into orbit requires engineering designs that can vary by at most one part in 10 000, or something like that. I don't know what exactly we owe to the space program, although I know it isn't computers, and it isn't teflon. IBE (talk) 18:27, 30 November 2012 (UTC)

Orange Tang. SteveBaker (talk) 18:43, 30 November 2012 (UTC)

Certainly NASA didn't produce the first computer...who precisely did depends crucially on your definition of the word "computer"...Atanasoff–Berry Computer (circa 1942) is the most likely candidate...but there are reasons to say that it doesn't count. Arguably, NASA owned the first small "microcomputer". NASA paid IBM to build a 19" long computer (weighing in at 60lbs!) in May 1963. It was used by NASA on the Gemini program and had a fairly respectable 16k bytes of memory. However, there is always a problem with "Without A, we wouldn't have B" arguments. Clearly, IBM had the technology to build this thing - so if NASA hadn't paid them to do it, what is to say that six months or a year later, someone else wouldn't have? Since computers were already in fairly widespread use in 1963 - it was only a matter of time before someone else built a tiny one. There is no evidence whatever that NASA's machine was widely copied - or that it is somehow the progenitor of all computers that followed it - to the contrary, it was not much more than a dumb calculator with far fewer features than it's contemporaries. SteveBaker (talk) 18:43, 30 November 2012 (UTC)

It seems according to the Computer page the Z3 was first computer (obviously depending on your definition of computer) in 1941. Dja1979 (talk) 20:20, 30 November 2012 (UTC)

Here in the UK, everybody knows that Colossus was the first computer. I think we should have a List of computers claimed to be the first computer. Alansplodge (talk) 20:38, 30 November 2012 (UTC)

To which we could add Charles Babbage's Analytical Engine of 1837, "the first design for a general-purpose computer that could be described in modern terms as Turing-complete." Alansplodge (talk) 20:45, 30 November 2012 (UTC)

At the Computer History Museum in Mountain View, California, the exhibition hall is set up so that the first items you see are historical computation contraptions dating to pre-history; such artifacts as abacuses and cuneiform tabulations. The exhibition hall progresses forward through more advanced mathematical machines; Babbage engines; punch-cards and time-clocks (other intricate mechanical devices that could perform domain-specific computation); Curta peppermills; and finally, after you've gone through a whole row of historic inventions, you finally see the first of the electronic and electronic-digital-machines that start to resemble what we call a computer. Like any question of history, there is much room for debate and different perspective. You can navigate an online version of the "Revolution" - the first 2000 years of computing, and the Computer History Timeline. The museum used to be free and open to the public; but now charges an admission fee. Nimur (talk) 22:02, 30 November 2012 (UTC)

Colossus was the first programmable computer. We have History of computing hardware, but it could use some work. --Tango (talk) 01:11, 1 December 2012 (UTC)

A more plausible argument is that without nuclear weapons, we wouldn't have modern computers. See e.g. ENIAC, Project Whirlwind, SAGE... It's still an historical fallacy (there's no reason to think that the computer wouldn't have been developed and funded for other reasons, and the history of computing is nothing but an endless string backwards of priority arguments over what counts as the "first computer" anyway), but it's more on target than the NASA reference — nukes, their deployment, and attempts to defend against them were much more influential in the short and long terms. --Mr.98 (talk) 00:37, 1 December 2012 (UTC)

Actually it was Nazis, not NASA or nukes that set America on the road to computing. You had not only the big push to break Axis power codes, but also the IBM sales to help manage the final solution. So it was a win-win, of sorts. :-( Hcobb (talk) 00:42, 1 December 2012 (UTC)

America? Surely you jest. The British were the ones who did the hard work on Nazi cryptography, and the only ones (I believe) who built anything that looked like computers for it. The Americans worked on Japan's and later the Soviet's codes but they were not terrible consequential with regards to the Nazis (and I'm not too sure of the role of computing, per se, in American cryptological efforts). And while I think the topic of IBM during World War II is of great interest, I think saying that the Holocaust really advanced computing is a bit much. The Hollerith sorting machines, while useful, weren't really computers in the modern sense at all. (Neither, really, was Colossus, but it was a step along the way.) For American computing, nukes played a much bigger role than cryptography, initially. --Mr.98 (talk) 03:27, 1 December 2012 (UTC)

As has been pointed out before, Americans who read American books etc think that Americans invented the computer, as is understood in modern times by the term - i.e., a machine that can be programmed, at any time after commissioning, to do a multitude of unrelated things. And the British, who read British books, like to think that the British invented the computer, even though the code breaking apparatus and even the later university computing machines do not conform to this meaning. However, Conrad Zuse, a German, beat all of that, having a fully programmable computer in commercial use before any of that. Yep - the Germans were first. See http://en.wikipedia.org/wiki/Zuse. At the time British and American airplane manufactures were using "loft computers" (rooms full of dozens of junior engineers doing wing design and stress calculations manually), German airplane manufacturers were using a Zuse computer to do it. Be carefull about the claims about the British cracking the German enigma messages. British media have made much noise about it practically ever since, and good on them. But it was very specialised with little or no commercial value, and the Americans did important work too - they just kept good and quiet about it. Keit 121.221.37.153 (talk) 06:08, 1 December 2012 (UTC)

" Americans... just kept good and quiet about it" See U-571 (film). Alansplodge (talk) 12:28, 1 December 2012 (UTC)

blocking in experimental design

Resolved

I understand (more or less) what a block is in experimental design, but I don't get what the authors are talking about here when they say "In addition, although blocking subjects on initial interest in the target activity of course eliminated any between-groups differences in this variable,..." What is this "blocking subjects" referring to? In a block design, I thought the blocks were supposed to be arranged in advance, and furthermore, our article states "A nuisance factor is used as a blocking factor if every level of the primary factor occurs the same number of times with each level of the nuisance factor". This doesn't look like something you could arrange after the experiment. What's going on? IBE (talk) 18:23, 30 November 2012 (UTC)

I'm not sure what is confusing you. The article describes the blocking and the assignment of subjects to groups as arranged before the experiment, as far as I can see (p. 131, upper left). Looie496 (talk) 19:30, 30 November 2012 (UTC)

Perhaps it's the use of the word "subjects", meaning "people on whom we experiment" versus the more common meaning of "topics" ? StuRat (talk) 03:35, 1 December 2012 (UTC)

No, I had just missed the bit that Looie pointed out. I did read most of the article, but I would have skimmed over that bit, and my inexperience confused me. I should have at least done a ctrl-f, because the article is searchable. I was just thrown by something that seemed to come out of left field. Thanks for pointing it out. IBE (talk) 08:22, 2 December 2012 (UTC)

Electrical Properties of Tubes

What if instead of wires we were to use tubes (of copper, say for indoor wiring)? Would there be any advantages/disadvantages and are there any special electrical properties of such a configuration? Seems as if the current would travel on the outer surface mostly, but I'm just guessing, honestly. 66.87.126.32 (talk) 20:51, 30 November 2012 (UTC)

I believe this was done, in some places, specifically with the tube carrying either positive or negative, with a regular insulated wire inside carrying the opposite charge. There are several disadvantages, though:

1) Not flexible, so much harder to install and maintain, especially where bends are needed.

2) Takes up more space.

3) Requires more electrical insulation.

4) Since it's uncommon, people might not realize it's carrying current, and be electrocuted.

5) Access to the interior wires is more difficult.

Using the tube as ground/earth with both positive and negative insulated wires inside makes more sense, especially out-of-doors, where the tube provides additional protection from the environment, for the wires. The tube might also function as a structural support, say when using a flagpole as the ground/earth for a light placed on top, with wires running inside. StuRat (talk) 21:51, 30 November 2012 (UTC)

The one-conductor-inside-another layout is termed coaxial cable. As the article indicates, it's used mostly for RF signal transmission (where it has beneficial properties), although the configuration has been used for power in certain situations, though attempts to search for a good reference are swamped by mentions of coaxial power connectors. - By the way, the article Skin effect shows a three-wire-bundle high-voltage power line, mentioning that because of the skin effect, they're effectively one conductor, which is taking the tube-as-conductor idea one step further. -- 205.175.124.30 (talk) 22:20, 30 November 2012 (UTC)

Except that coax cable is flexible, and I think the OP means rigid pipes. StuRat (talk) 03:38, 1 December 2012 (UTC)

The OP asked about using tubes as conductors, saying "thinking most of the currrent flows on the outer surface", indicating he's heard about skin effect - where the magnetic field created by alternating current opposes the flow of current where the field is strongest, which is inside the conductor. However, for skin effect to the significant, the conductor diameter must be large enough, and/or the frequency must be large enough. In the design of high power radio transmitters, both factors apply and the use of tubing instead of solid wire is common. In the design of low and medium power electronics, another solution is used - litz wire. In the transmission of electrical power at 100's of megawatt levels, the diamter is large enough for skin effect and proximity effect (the magentic field from one conductor can aid or oppose the current in an adjacent conductor) to be significant and hollow conductors are used, as well as the grouped conductors mentioned by 205.175.124.30. Often, the conductors consist of a central steel tension member surround by copper strands. The steel supplies the mechanical strength without affecting the electrical properties too much. In domestic house wiring, the wire diameter is way too small for skin and proximity effects at the frequency used to be significant, and it's cheapest to just use solid wire or normal stranded wire. Keit 124.182.170.42 (talk) 01:18, 1 December 2012 (UTC)

Does the "magentic field" cause nearby objects to turn magenta ? :-) StuRat (talk) 03:42, 1 December 2012 (UTC) ~

One for you and one for me, Stu. You can get flexible pipe, and you can get rigid coax, which is often used in professional radio equipment. I agree though, that the OP didn't mean coax. Keit 121.221.37.153 (talk) 05:58, 1 December 2012 (UTC)

Very elucidating, thanks so much! 66.87.126.32 (talk) 01:38, 1 December 2012 (UTC)

Just adding that, in the UK, older 2-wire mains supply wiring to properties is being replaced with a "co-axial" cable where the "live" is on the inside, and the neutral is a stranded "tube" around the outside. This is for safety, of course. I don't know whether it is used in other countries. Dbfirs 08:30, 1 December 2012 (UTC)

In Australia, as in most other countries, you get two applications: 1) Fireproof MINS cabling - this has an active solid conductor in the centre, surrounded by mineral insulation, in turn surrounded by a metal tube. But the tube is not a neutral or return conductor - it is earthed, and only carries current under fault conditions. It's there because the mineral insulation must be surrounded by metal for mechanical reasons. It is only used, in buildings, where the supply of electricity must survive a fire. 2) Underground high voltage street cabling also is coaxial, with one coax for each of the three phases, with the outer "tube", termed the "screen" comprising of strands and functioning as the neutral/earth per Multiple Earth Nuetral practice. Here the coaxial construction is used for three reasons; a) there is no external magnetic or electric field, which is important with underground cables as a significant field could cause soil heating and be a hazard for humans and animals (or power loss/dissipation in the outer steel wire armouring if fitted, which it usually is), b) if the cable is cut by say a backhoe, the screen must be penetrated first, and will always be there to carry away the fault current and avoid high voltage on the backhoe. c) it shields the outer plastic sheath from electrical stress, and avoids a touch shock/tingle hazard on the outer plastic sheath via capacitance. Keit 60.230.222.186 (talk) 10:47, 1 December 2012 (UTC)

Okay, so consider a bare, tubular conductor in air connected in series with a power circuit. Does the majority of the current travel on the outer or inner surface? What if the conductor was dipped in an insulator? What would be the differences between using a DC and AC power supply? 66.87.127.92 (talk) 20:49, 1 December 2012 (UTC)

With DC, the current flows smoothly and continuously. With a tube conductor, the current does not flow on the outside surface, nor does it flow on the inside surface. DC flows evenly distributed throughout the thickness of the conductor, just as it flows with the even density throughout a conductor of any shape. To see why this is so, recall that any electrical conductor offers resistance to the flow of current. Take your tube conductor - you can consider it as consisting of any number of tightly fitting concentric thin tubes - all having the same electrical resistance per unit cross-sectional area, and each thin tube electrically in parallel with the other thin tubes.

With AC, two effects, known as skin effect and proximity effect come into effect. These effects depend on frequency. Frequency is the rate at which the current alternates from one direction to the other. The alternation sets up an alternating magnetic field that causes skin and proximity effect. The higher the rate of alternation, ie frequency, the faster the rate of change in magnetic field and thus the stronger the skin and proximity effects. (DC has zero rate of change, so zero skin and proximity effect). In a solid circular cross-sectional wire, the magnetic field opposes the flow of current, and the opposition is strongest where the magnetic field is strongest, which is in the centre of the conductor. So, at a frequency high enough, the current is minimal in the centre - this is skin effect. The higher the frequency, and the bigger the diameter of the wire, the greater the fraction of current forced to flow near the outer surface. If the frequency is very high, a tube works just as well, as any metal in the centre isn't doing anything - at extreme frequency, the current flows close to the outer surface of a tube.

At power main frequencies, skin effect is negligible at the wire sizes used in houses, and the current is evenly distributed throughout the conductor cross section just as it is with DC, regardless of whether the conductor is a solid wire, a tube, or some arbitrary shape.

At frequencies high enough for skin effect, if the are two parallel routed conductors, carrying current in opposite directions (as in one conductor carrying the return current from a load, the conductors insulated from each other), the magnetic field of one conductor will aid the current in the other conductor. Thus the current in each conductor tends to be concentrated in the part of the conductor cross section nearest the other conductor. This is called proximity effect. If two parallel routed conductors are both carrying current in the same direction, proximity effect will tend to force the current to flow in the part of the conductor cross section furtherest away from the other conductor.

As skin and proximity effects are driven by magnetic fields, the type of insulation around the conductors has no effect on them. However the presence of any ferromagnetic material and other parallel routed conductors (if earthed at both ends) such as steel conduit does affect skin and proximity effects.

Keit 124.182.167.109 (talk) 07:35, 2 December 2012 (UTC)

Okay, I think I understand now. Thanks again Keit for the excellent explanation. Cheers! 66.87.126.240 (talk) 14:48, 2 December 2012 (UTC)

When did the last visible (with naked eye) star appear in the sky?

Did Jesus looked at the same sky as us? Comploose (talk) 21:08, 30 November 2012 (UTC)

Pretty much, with a few exceptions. Some stars only become visible as a result of a nova or supernova. A new star being ignited might only very slowly become visible to us, as the dust clouds around it clear. The Earth's precession also makes different stars into the pole stars every so often (Polaris isn't always the North Star). There are also periodic comets which are only visible certain years, like Halley's Comet. See List of periodic comets. StuRat (talk) 21:18, 30 November 2012 (UTC)

Timeline_of_white_dwarfs,_neutron_stars,_and_supernovae is your friend :) Dr Dima (talk) 21:26, 30 November 2012 (UTC)

Proper motion also has an effect; a star might be nearer or further away, or in a slightly different place relative to others. But 2000 years is a pretty short timescale for such things; while there were differences, most of them were subtle. I don't think any significant naked-eye stars have appeared or disappeared in that time. AlexTiefling (talk) 21:28, 30 November 2012 (UTC)

They haven't appeared of disappeared, but some of them have moved noticeably. According to our article on Alpha Centauri:

"Edmond Halley in 1718 found that some stars had significantly moved from their ancient astrometric positions.[63] For example, the bright star Arcturus (α Boo) in the constellation of Boötes showed an almost 0.5° difference in 1800 years,[64] as did the brightest star, Sirius, in Canis Major (α CMa).[65] Halley's positional comparison was Ptolemy's catalogue of stars contained in the Almagest[66] whose original data included portions from an earlier catalog by Hipparchos during the 1st century BCE"

Alpha Centauri itself has a much larger proper motion than Arcturus or Sirius, and moves by 1 degree per millenium. For reference, that's about the width of your thumb at arm's length, or twice the angular diameter of the Sun or Moon.

So in conclusion, Jesus' sky would have looked almost identical to ours, with the exception that the north pole would have been in between Polaris and Kochab instead of very close to Polaris (see http://en.wikipedia.org/wiki/File:Precession_N.gif). --140.180.249.151 (talk) 23:22, 30 November 2012 (UTC)

We're forgetting about something here:

The sky as seen by Jesus:

"Class 1: Excellent dark-sky site. The zodiacal light, gegenschein, and zodiacal band (S&T: October 2000, page 116) are all visible — the zodiacal light to a striking degree, and the zodiacal band spanning the entire sky. Even with direct vision, the galaxy M33 is an obvious naked-eye object. The Scorpius and Sagittarius region of the Milky Way casts obvious diffuse shadows on the ground. To the unaided eye the limiting magnitude is 7.6 to 8.0 (with effort); the presence of Jupiter or Venus in the sky seems to degrade dark adaptation. Airglow (a very faint, naturally occurring glow most evident within about 15° of the horizon) is readily apparent. With a 32-centimeter (12½-inch) scope, stars to magnitude 17.5 can be detected with effort, while a 50-cm (20-inch) instrument used with moderate magnification will reach 19th magnitude. If you are observing on a grass-covered field bordered by trees, your telescope, companions, and vehicle are almost totally invisible. This is an observer's Nirvana!"

The sky we see today:

"Class 9: Inner-city sky. The entire sky is brightly lit, even at the zenith. Many stars making up familiar constellation figures are invisible, and dim constellations such as Cancer and Pisces are not seen at all. Aside from perhaps the Pleiades, no Messier objects are visible to the unaided eye. The only celestial objects that really provide pleasing telescopic views are the Moon, the planets, and a few of the brightest star clusters (if you can find them). The naked-eye limiting magnitude is 4.0 or less."

Count Iblis (talk) 23:30, 30 November 2012 (UTC)

The sky as seen by Jesus. Merry Christmas! Thincat (talk) 12:21, 1 December 2012 (UTC)

Small angle formula

D = X · d / 206,265

What is the difference between D and d? They are both distances so can someone explain the difference to me in an easy way to understand?Pendragon5 (talk) 21:52, 30 November 2012 (UTC)

It appears to me that your formula is a special case of arc length of a circle, commonly denoted as $s=r\times \theta$; but you've got it in a form where the radius angle is presented in normalized units (your constant 206,265). I didn't recognize that constant off the top of my head, but it wouldn't surprise me if it's related to, e.g., a special case of angular resolution. And, lo and behold, it's a conversion constant to arc-seconds, when d is the radial distance to the target, and D is the linear size of the object, and X is measured in radians. 206265, a unit conversion factor I don't have any common use for.

So, in plain english: d is the distance to the object, and D is the size of the object. This case-sensitive notation is a little ugly. Perhaps it derives from an era when ink was much more expensive. Nimur (talk) 22:27, 30 November 2012 (UTC)

What do you mean by the size of the object? Its diameter? Its radius? Its mass? Or what?Pendragon5 (talk) 23:32, 30 November 2012 (UTC)

To be perfectly pedantic, it's none of those things. It's the cross-section, determined by the appropriate projection geometry of your optical system. For simple geometrical objects, like stars and planets that are spherical, this value is well-approximated by the diameter. Nimur (talk) 00:07, 1 December 2012 (UTC)

December 1

Magic bread or...?

Beginning at about 4:40 in this video, an illusionist does something that I'm pretty sure is impossible... At least, in all the years I've spent studying sleight of hand and the like, I've never seen anything that should enable one to do something like that. Any thoughts on how that's done? Evanh2008 ^{(talk|contribs)} 06:35, 1 December 2012 (UTC)

Looks like a camera trick to me. That is, they stop filming, put a small piece of bread in his hand and let him pull it out, then stop filming and put a larger piece of bread in his hand, etc. I think I can see the cuts. Also, that bread is just too large to have been up a sleeve, etc. This does, of course, mean that the "audience" were just shills, pretending to be impressed. (The trick camera work could also have involved hiding the full piece of bread behind a green screen, then digitally replacing the green screen with the background, but I think it's just jump cuts.) StuRat (talk) 08:48, 1 December 2012 (UTC)

BTW, does the person who posted it know his name is listed as "Yi Fart of Magic" ? :-) StuRat (talk) 08:51, 1 December 2012 (UTC)

I don't see any cuts. It looks like green screen to me, with actors for the "audience reaction". Red Act (talk) 15:48, 1 December 2012 (UTC)

Actually, there is a cut before the audience reaction. So the video could start with a green screen effect, followed by a real audience reaction to a simpler trick that produces a baguette. Red Act (talk) 15:55, 1 December 2012 (UTC)

• It's behind his back and he's pulling it around. Look how flexible it is. Looie496 (talk) 17:03, 1 December 2012 (UTC)

I watched a program once a while back showing how magicians use powerful retractable strings to exchange items from either up their sleeves or from behind their clothes. For the long bread loaf trick, he appears to be using one coming from under his very large shirt collar which becomes pulled upward by the bread, before it drops back down to his chest... perhaps due to the string pulling the large dough ball into his shirt after the bread was pulled out from underneath (the large loaf must be compressed within a smaller diameter tube to reduce its bulk and the tube might be sealed to maintain an increased air pressure within the bread, causing the bread to expand rapidly when removed, and in addition, the air pressure may help expedite its removal from the tube too). He would simply need to extract a difficult to see hook mechanism (behind the collar and partially visible at the 3:24 mark) and then uses his free hand's thumb to plant the hook firmly between his fingers behind the dough. Note also that when the collar is raised it is not folded in place like a typical collar, but it separates from the shirt when this happens, allowing the bread to remain hidden behind cloth from viewers on either side of him. It also appears that the croissant may have been undercooked and turned inside out through a small cut centered on its uppermost edge. He would either had to given it to the deli prior to the taping or switched their dough for the prop, perhaps during the cuts. -Modocc (talk) 23:40, 1 December 2012 (UTC)

I've studied magic for many years and while i certainly wouldn't claim to be an expert, I'm pretty sure there is a camera trick involved in the large baguette production, some magicians are definitely not against using such tricks. Vespine (talk) 05:55, 2 December 2012 (UTC)

Not to my eye or reasons.. The loaf of bread can easily be concealed once compressed and he just so happens to be wearing something that is poking out slightly from beneath his collar (and its not attached to the collar because its poking out from the shirt in later frames), so what is it? Had he used a camera trick, he would have no need to be wearing that unusually tailored shirt or any hardware beneath it. Why would the collar be lifted? He also may also being using string to swap the colored rubber bands and the use of retractable strings (or elastic bands) to remove or disappear objects (the dough in this case) is a common method of concealment. Furthermore, his various audience's reactions appear genuine to me and I don't see any hint of a green screen (I've seen these screens used countless of times and they tend to be noticeable for various reasons). That he is able to pull his tricks off as well as he does simply speaks highly of his skill. For these reasons, I don't believe he resorted to doing a cheap camera trick that just about anyone could do. But of course, I could also be wrong... :-) --Modocc (talk) 06:23, 2 December 2012 (UTC)

I don't see a large collar and a hook. I see a scarf (presumably used in another one of his tricks) and a microphone. And the bread would have to make a 90 degree bend to come out from under the scarf. I believe he just bumps the scarf with the large piece of bread. And, if green screening is done properly, it's not visible on the final video. StuRat (talk) 07:10, 2 December 2012 (UTC)

It is a highly flexible piece of bread, and a narrow tube that conceals it could help with bending it if its been pulled out to his hand (the hook itself, should one be used, could be smaller and less visible than the mic), but his hands may not be close enough to his shirt for that not to be noticeable. The bread seems to expand some, up until he breaks it in two (conformation bias on my part I'm sure). Plus, it would be to his advantage to be able to perform the trick on demand (for more gigs) than only with a green screen production. But that's what his videos are, and of course I was completely wrong about the shirt. Fair enough. My vision isn't what it used to be. -Modocc (talk) 08:23, 2 December 2012 (UTC)

The bread does seem to grow in size between cuts, which is one reason I suspect trick photography. StuRat (talk) 08:45, 2 December 2012 (UTC)

re: green screens, that's called the toupee fallacy, you've seen green screens only when they've been executed poorly, if they were done well you didn't notice them, so you think they are all poor. Also, reproducibility is not a factor for a magician doing a YouTube or television performance, I don't think ALL the tricks were rigged with camera tricks, but I do thing the baguette one in particular was. As for reactions, they are actors, they are paid to give genuine looking reactions. Have you seen this clip? Criss Angel is a far more known magician, in the west at least, and this clip was exposed as completely staged, he used actors, one of them an actress with a Hemicorporectomy and creative editing, that's it, no "magic" involved at all. I agree, it's cheap, but some magicians are not beneath using them. Vespine (talk) 08:46, 2 December 2012 (UTC)

Most seemingly impossible shots are green screen, thus it is likely that it is a well-executed green screen. This too is an inductive leap and I didn't say all green screen are poor. I was just pointing out that there was no validating evidence yet given showing that it is one (and lots of so-called "evidence" and testimony that it is a green screen), but I do agree that its probably a green screen. -Modocc (talk) 09:26, 2 December 2012 (UTC)

@StuRat Yes, trick photography is definitely possible. On the other hand, after its initial rapid inflation (think cosmology here, :-)) the air in the bread still had some residual pressure left within its pores to expand further, albeit more slowly. Modocc (talk) 10:07, 2 December 2012 (UTC)

I'm rather skeptical that instantly rising, edible bread in a tube actually exists. If it does, it should be sold to consumers, where it would be a party hit. StuRat (talk) 18:50, 2 December 2012 (UTC)

How should "望闻问切" in Traditional Chinese medicine be translated into English?

Seemed this is not covered in the English article, and the Chinese article zh:中医诊断学 which this term redirects does not have an English correspondent--Inspector (talk) 13:41, 1 December 2012 (UTC)

You might want to delete this and repost it at the language desk instead. μηδείς (talk) 17:39, 1 December 2012 (UTC)

Google Translate renders it as "look and smell". Looie496 (talk) 17:49, 1 December 2012 (UTC)

This is an instance where I would not trust a machine-translation at face value. Reading many of our articles, I found a citation in our Medical Diagnosis article. These characters translate literally as "look, smell, ask, cut." I also found this phrase, commonly coincident with the other characters: 中医四法, which translates as "the four methods of medical diagnosis." Elsewhere, I have seen these enumerated: "looking, listening, questioning the patient, and checking the pulse." The exact methods vary from source to source. It is my opinion that "check the pulse" is a rather euphemistic translation, now that bloodletting has fallen out of favor, but as I read 切, I interpret "make a giant carving." I'm not fluent in any of these languages, though. It appears that these are general descriptions of "methodology," and not a description of an exact procedure. Sometimes that last one is called "cutting" or "incision." Now, if I could only find out which simplified Chinese characters represent germ theory of disease, I could work on bridging the cultural- and linguistic- barrier for the betterment of medical practice everywhere! In all seriousness, is there even such a concept in traditional Chinese medicine? I have not been able to find any reference to the idea - the fact - that for at least some ailments, we have actually ascertained the root-cause to a specific infectious microbe. Our article on traditional Chinese medicine discusses folklore conceptions of disease, but makes no mention of any attempt to consolidating that world-view with new factual evidence. Nimur (talk) 20:21, 1 December 2012 (UTC)

(*facepalm*) Guys/gals, the Chinese article tells you exactly what 望闻问切 means. That's probably why the OP linked to it--he understands the article, but doesn't know how to properly translate the name into English.

Quoting from the Chinese article:

In Traditional Chinese Medicine, the "four methods" is the collective name for basic methods of medical checkup, including "sight checkup", "listen/smell checkup", "asking checkup", "feeling checkup", hence 望闻问切. 望means observing the patient's bodily condition, including facial color, tongue, etc; 闻means listening to the patient talk, cough and breathe, and smelling his breath or body for abnormal odors; 问means asking the patient about his condition, disease history, etc; 切means using the hand to check the pulse or press the abdomen to see if anything is unusual. Through the "four methods", the checkup reveals all types of symptoms and characteristics, for the purpose of understanding the disease's origin, character, and relationship with the internal organs, to provide a sufficient basis for diagnosis.

切cannot possibly mean bloodletting, because that's not a diagnostic method, there's no evidence that anybody used bloodletting in TCM, and 切 has numerous meanings depending on context, and the one for "cut" has a different pronunciation than the one for "ascertain/correspond". That article on 切土 is Japanese, not Chinese, and as the article says, 切土 means cutting through a hill to build a flat path through it. I don't know what the corresponding word is in English, but again, 切 has a different pronunciation in this context than in 望闻问切. The Chinese term for the germ theory of disease is 疾病细菌学说 or 疾病细菌说 (literally "disease germ theory"). As for why TCM doesn't mention it, it's because the germ theory of disease is an 19th century European invention while TCM is an ancient pseudoscience. If TCM made any sense at all, it wouldn't be "alternative medicine" (read: utter bullshit); it would be Western medicine (西医). --140.180.249.151 (talk) 20:25, 2 December 2012 (UTC)

Why in some countries, HIV\Hepatitis C tests are after 2 months and in others 3 months (of suspicious contact) ?

Why in some countries, HIV\Hepatitis C tests are after 2 months and in others 3 months (of suspicious contact) ? Thanks. 79.182.153.70 (talk) 22:32, 1 December 2012 (UTC)

Two or three months after what? Can you clarify and give some context for your question? RudolfRed (talk) 22:38, 1 December 2012 (UTC)

i did that (read the header again). — Preceding unsigned comment added by 79.182.153.70 (talk) 23:06, 1 December 2012 (UTC)

I think the short answer is that such decisions are driven by logistical considerations, after a scientifically-reasonable range of options has been established. For both HIV/AIDS and Hepatitis C, seroconversion occurs 1-2 months after onset of infection (i.e. an exposure resulting in infection). Examples of evidence for this are here and here, more specifically for HCV PMID. So, testing at 2-3 months will detect most seroconversions, though some have suggested testing at 6 months as well to avoid missing late seroconversions (this is exceedingly uncommon with current tests). -- Scray (talk) 05:38, 2 December 2012 (UTC)

More data for HIV PMID 20846033 and HCV PMID 22715213 and PMID 11264728. -- Scray (talk) 05:55, 2 December 2012 (UTC)

December 2

Garlic supplements

I take garlic supplements and usually buy whatever's on sale at the grocery store. I happened to notice that brand I bought last time, Sundown Naturals has 75 mgs of garlic. The brand I just bought today, Nature's Bounty has 1000 mgs of garlic. I realize that there's no established RDA for garlic, but I was surprised that the amounts are so wildly different. The lower dosage pill is bigger, too. I'm guessing that one of these companies is playing 'accounting games' with the amount of garlic and that one pill isn't really 13 times more potent than the other, but I don't know that. Can anyone shed some light on what's going on here? Thanks. — Preceding unsigned comment added by A Quest For Knowledge (talk • contribs) 01:26, 2 December 2012 (UTC)

The label for the Sundown product says it contains 400 mg of garlic extract, equivalent to 2000 mg of fresh garlic bulb. Looie496 (talk) 01:39, 2 December 2012 (UTC)

(edit conflict) Herbal supplement#Government regulations should provide some light; basically the entire world of herbal supplements is an impenetrable dark morass of unproven, untested, and unregulated products foisted on the public as "health". It's not harmful (maybe), so there's no reason you shouldn't be taking them, but otherwise, don't actually expect any real consistency or meaningful efficacy from over-the-counter herbal supplements, most of which are about as useful as snake oil. --Jayron32 01:41, 2 December 2012 (UTC)

@Looie496: Oh, that's interesting. The label has apparently changed since I bought it. A Quest For Knowledge (talk) 01:51, 2 December 2012 (UTC)

@Jayron32: I did a bit of research on garlic a couple months ago, and I don't think this was the article I read, but there appears to be some support for garlic and hypertension, Garlic 'remedy for hypertension'. A Quest For Knowledge (talk) 01:51, 2 December 2012 (UTC)

I am in no way doubting that there could be medically useful compounds in garlic. There very well may be. The issue is that the herbal supplement industry is essentially an unregulated industry with no set standards the way that actual medicines have. So yeah, the fact that there are compounds within garlic that reduce hypertension is to me unimportant to the discussion at hand. The question is whether pills in stores by random manufacturers which report some content of "garlic" are useful or consistent. They are different questions. --Jayron32 01:55, 2 December 2012 (UTC)

Plus, with all these vampire shows, like Twilight: Breaking Wind, I assume there's a plague of vampires right now, so having some garlic in your system to ward them off is a good idea. :-) StuRat (talk) 07:17, 2 December 2012 (UTC)

From a culinary point of view, eating garlic is much better than eating garlic pills. 2000mg is two grams, or about one clove - a homeopathic dosis, as far as my cooking is concerned. The natural unit of measurement is the bulb, not the clove ;-). --Stephan Schulz (talk) 08:52, 2 December 2012 (UTC)

There are some of us who hate garlic. And, even for those who love it, do you really want to smell like garlic ? StuRat (talk) 09:12, 2 December 2012 (UTC)

Well, the unenlightened need to become enlightened. And I'm not sure that "smell" is the proper term to use for the heavenly fragrance that garlic and its disciples contribute to the universe. More seriously, I've cooked some meals for people who claim to not like garlic, and they where quite happy with it. It always depends not only on "how much", but also on "how", with garlic added early and sautéed a bit being much easier on the stomach and more discrete on the taste buds than raw garlic. --Stephan Schulz (talk) 09:20, 2 December 2012 (UTC)

I want to know some intersest things about how metal found

Any kind of metal — Preceding unsigned comment added by Summeru (talk • contribs) 11:04, 2 December 2012 (UTC)

Iron can fall from the sky in the form of an iron meteorite. It can then be found lying on the ground. You may also be interested in the metal detector. Graeme Bartlett (talk) 12:04, 2 December 2012 (UTC)

In the spirit of providing interesting things about how metal is found, you might enjoy reading some excerpts from Roughing It, a narrative account by Mark Twain about his experiences as a silver miner in Nevada (and other excitement in the old West). Perhaps the author embellishes a little bit, but as far as I can tell, he presents an incredibly interesting (and quite potentially factual) account of ore extraction and processing. Chapter XXIX, Out Prospecting; Chapter XXXVI, A Quartz Mill and Ore Processing; Chapter LX, Pocket Mining, Placer Mining, and Mining Technicalities; and essentially everywhere else in the book, scattered bits of wisdom about silver and gold mining in the mid-nineteenth century. For an encyclopedic overview, we have articles on silver mining. Nimur (talk) 14:02, 2 December 2012 (UTC)

Maybe this is about discovery. (From our article on nickel): "In medieval Germany, a red mineral was found in the Erzgebirge (Ore Mountains) that resembled copper ore. However, when miners were unable to extract any copper from it, they blamed a mischievous sprite of German mythology, Nickel (similar to Old Nick), for besetting the copper. They called this ore Kupfernickel from the German Kupfer for copper. ... In 1751, Baron Axel Fredrik Cronstedt was trying to extract copper from kupfernickel—and instead produced a white metal that he named after the spirit that had given its name to the mineral, nickel."--Fuhghettaboutit (talk) 14:43, 2 December 2012 (UTC)

metal from Lithium and magnesium to cooper and silver and gold had been exist in earth crust and found by man for duration of some thousand years,we dont know clearly about first mining and how could man find minerals,but the usage of minerals and metal goes to age 8-9 thousand years ago. now we have instruments and high technology for mining ,the way of separating of mineral matters on earth crust refers to its molten core and diffraction of layers for duration of its life(4.6 billion years)--Akbarmohammadzade (talk) 15:03, 2 December 2012 (UTC)-

Photobiolysis

Do we have an article? Is there a missing redirect? Did I make a typo? See [here] for an explanation of what the term means. As of 13:32, 2 December 2012 (UTC), the title of the question is a redlink. Thanks, NorwegianBlue ^talk 13:32, 2 December 2012 (UTC)

Biohydrogen, Photohydrogen, and Biohydrogen reactor all seem to be related. To which, if any, "Photobiolysis" should redirect I'll leave to others more versed in the material. Deor (talk) 17:08, 2 December 2012 (UTC)

what does burn in nature

we had discussion about matters does burn by fire . they said :only matters made of carbon does burning.what about others? --Akbarmohammadzade (talk) 14:41, 2 December 2012 (UTC)— Preceding unsigned comment added by Akbarmohammadzade (talk • contribs) 14:40, 2 December 2012 (UTC)

Many elements burn, including metals and hydrogen gas. Most pyrotechnics do not seem to have carbon. DMacks (talk) 17:02, 2 December 2012 (UTC)

If you can oxidate it, you can burn it. When you "burn" something you simply combine it with oxygen, you oxidize it. Magnesium burns, and it's not organic, for example. OsmanRF34 (talk) 20:11, 2 December 2012 (UTC)

what do you thinking about this questions?

پرسش از چگونگی اندر کنش گرانش و فضا؟

گراویتون ها(ریزگانهای نامزد ترابری نیروی گرانش ،موجب خمیدگی فضا نمی شوند . حضور میدان در فضا با مبادله ذره تفاوت ماهوی دارد و این را اینشتین به خوبی درک کرده بود. ببینید شما روی صندلی نشسته اید و صندلی برروی سقف قرار دارد و سقف روی ستونها و ستونها روی قشری از پوسته زمین . مثال ساده فوق را اینطور تصور کنید : ذرات گراویتون از زمین (معلوم نیست از کجای زمین)به شما واجسام یادشده گسیل میشود . 1- چه عاملی باعث می شود زمین تشخیص دهد شما اینجائید تا ذره گسیل دارد؟ 2-چرا مواد و اشیا زیر شما بین شما و زمین سایه نمی اندازد؟(مانع برای رسیدن گراویتون) 3- چه چیزی به زمین می گوید شما چقدر جرم دارید تا همان اندازه گراویتون گسیل نماید. 4-گراویتون به هیچ و جه توجیهی برای افزایش شتاب به نسبت عکس مجذور ثانیه و شتاب یافتن ذره در میدان نمی آورد. 5-هیچ مبادله کوانتومی ذره استثنا از قانون پلانک و اصل طرد پائولی نیست. 6-ترازهای انرژی میدان جاذبه از اصل عدم قطعیت هایزنبرگ تبعیت نمی کند. 7-مبادله ذره قوانین کپلر و میدان جاذبه و حرکت در میدان جاذبه را نمی تواند توصیف کند. — Preceding unsigned comment added by Akbarmohammadzade (talk • contribs) 14:43, 2 December 2012 (UTC)

This is the English Wikipedia and so this question written in Persian is not well suited here. Moreover, from what I can make out from machine translation, this appears to be a homework question, which we will not answer for you because it robs you of the ability to learn yourself. I will post machine translation of this answer into Persian. I hope it's less garbled than the translation I was given of your text.ویکیپدیای انگلیسی است و بنابراین این سوال است از این بخش است که به زبان فارسی نوشته شده است و مناسب اینجا نیست.علاوه بر این، از آنچه که من می توانم از ترجمه ماشینی، این به نظر می رسد یک سوال برای مشق شب، که ما آن را نمی خواهد جواب را برای شما به دلیل آن را به شما محروم می سازد از توانایی خود را یاد بگیرند. من به ترجمه ماشینی از این پاسخ را به زبان فارسی ارسال کنید. من امیدوارم که آن را در کمتر از ترجمه من از متن خود را به او داده شد درهم است.--Fuhghettaboutit (talk) 14:52, 2 December 2012 (UTC)

Gravitons (gravity transport candidate, not the curvature of space. Field presence in space has an inherent difference between the particle and the Einstein exchanged well understood. If you see sitting on the chair and sits on the roof and on the roof of the cortical columns and pillars of the earth's crust. Imagine a super simple way: Graviton particles from the ground (not sure which part of the land) will be sent to you Ballistics above. 1 - You are here to determine what causes the particles are emitted? 2 - Why the materials and objects between you and the ground you would not have a shadow? (Barrier for gravitons) 3 - What is the land mass tells you how you can send the same size gravitons. 4- Graviton anything quite excuse for the acceleration inversely square s and acceleration of particles by the field 5 - No swap Pauli exclusion principle is a quantum particle exception of Planck's law. 6 - Energy balances the gravitational field does not obey the Heisenberg uncertainty principle. 7 - sharing particles of the gravitational field and Kepler's laws of motion in the gravitational field can not describe. is this translation clear enough ? — Preceding unsigned comment added by Akbarmohammadzade (talk • contribs) 15:12, 2 December 2012 (UTC)

your name is as difficult as my name,i cannot spell it. — Preceding unsigned comment added by Akbarmohammadzade (talk • contribs) 15:18, 2 December 2012 (UTC) If you want to justify graviton field must first be applied to the total impedance playing field with those particles like photons in space to justify. Each crime should be displaced between Dvtraz energy part of the gravitational energy is emitted. According to Maxwell's equations for the gravitational field Nakarast and radiation or certain wavelengths of emitted gravitational field graviton is not so controversial as the transferor remains Abtr field. The concept of gravity as the curvature of space electrodynamic equations of motion of a particle with space-time with virtual Chharbdy tensor is solved. The extent of the equations Bapkhsh just purely particle radius dependent impedance or density or mass or unresolved issue is resolved--Akbarmohammadzade (talk) 15:46, 2 December 2012 (UTC)

difference between theory and law

we have Faraday or Kepler or thermodynamic laws . so we have several theories about differences between theory and low: A common misconception is that scientific theories are rudimentary ideas that will eventually graduate into scientific laws when enough data and evidence has been accumulated. A theory does not change into a scientific law with the accumulation of new or better evidence. A theory will always remain a theory; a law will always remain a law.

http://en.wikipedia.org/wiki/Scientific_theory

A law differs from a scientific theory in that it does not posit a mechanism or explanation of phenomena: it is merely a distillation of the results of repeated observation. As such, a law is limited in applicability to circumstances resembling those already observed, and is often found to be false when extrapolated.

http://en.wikipedia.org/wiki/Scientific_law--Akbarmohammadzade (talk) 14:49, 2 December 2012 (UTC)

What's your question? --Mr.98 (talk) 15:32, 2 December 2012 (UTC)

something about how we say newton formulas law? — Preceding unsigned comment added by Akbarmohammadzade (talk • contribs) 15:43, 2 December 2012 (UTC)

I don't understand your question. You might like to read Newton's laws of motion and Physical law.--Shantavira|^{feed me} 18:03, 2 December 2012 (UTC)

Looking for research on Tetrahydrocannabinoids (THC) use as appetite simulant in cats diagnosed with CHF vs: azotemia (cardiac vs: kidney) problems - common in some cats.

Tried the orexigenic route via Wiki without much success. We are currently using Mirtazapine per vet with mixed results.This guy is a lovable little furry person! — Preceding unsigned comment added by 99.146.148.92 (talk) 15:53, 2 December 2012 (UTC)

I think we probably ought to avoid giving advice here, even if it is for a cat rather than a human. Plus this is such a technical question that nobody except a vet could give useful advice anyway. Looie496 (talk) 16:27, 2 December 2012 (UTC)

Humans, being primates, have large livers meant to metabolize chemicals in plants. Carnivores do not. The popular press has a lot on the toxicity of marijuana to pets. I'd speak to your veterinarian, if I were you. μηδείς (talk) 16:45, 2 December 2012 (UTC)

We are proscribed from providing medical advice (human and otherwise) here. This needs to be closed.Dncsky (talk) 17:42, 2 December 2012 (UTC)

Although it's obvious he wants to treat his cat, he has asked for research, which we can provide. μηδείς (talk) 17:56, 2 December 2012 (UTC)

Have you just tried more tempting foods ? I know my cat could never resist the oil from a can of tuna. (You can get the tuna packed in water, too, but that won't have as many calories for your cat.) Also, have you had the cat's mouth and throat checked ? A sore tooth or throat might make it avoid solid foods. StuRat (talk) 18:42, 2 December 2012 (UTC)

Synchronous belt as serpentine belts

I noticed that for most engines the serpentine belt is a multi-V belt. Is there any engine out there that uses synchronous belts as their serpentine belt? I can't see any reason they are not used other than the higher cost. But if cost is the only concern then some of the luxury and racing companies must've done it already. Google hasn't been helpful due to the synchronous belt/timing belt conflation.

Just to make it clear I'm not asking about timing belts; I'm asking about the belt that's used to transfer power from the crankshaft or camshaft to the various accessories. I'm wondering whether synchronous belts (commonly called "timing belts") have been used for this purpose.Dncsky (talk) 16:21, 2 December 2012 (UTC)

Fungus ID

I found this fungus after a couple of rainy days, in Southern California. Can anyone identify it? 69.111.189.155 (talk) 17:20, 2 December 2012 (UTC)

Possibly Sparassis crispa, known as the 'Caulifower fungus'? Mikenorton (talk) 17:33, 2 December 2012 (UTC)

Battery and voltage

Can you construct a battery with any combination of voltage and material? I know that certain materials have different electromagnetic forces when loaded, but you could always 'pile' them to get a higher voltage. And in the way down, you could just put a resistance to deliver a lower voltage than the output. Strangely, I am not seeing a lithium-ion battery in the form of AAA or AA battery on that market, although I would prefer it instead of alkaline AAA/AA batteries. OsmanRF34 (talk) 18:31, 2 December 2012 (UTC)

Googling "lithium-ion AAA" and "lithium-ion AA" gets me plenty of hits. They are certainly out there in the market. You don't see them more often because their voltage is too high. Lithium-ion chemistry provides 3.6V, much higher than the 1.5V expected in standard AAA and AA cells. The higher voltage might even damage the electronics. Your idea of adding a series resistance unfortunately won't work. Consider two loads, one 1MΩ load and a 1Ω load. Whatever series resistance you add to the battery will either make the current too high or too low.Dncsky (talk) 18:42, 2 December 2012 (UTC)

Yes, you are right that google gets you lots of hits, but they are by no means a replacement to the 'normal' AAA. OsmanRF34 (talk) 18:51, 2 December 2012 (UTC)

Like I explained, there's no easy way to step the voltage down. Putting a 3.6V battery in my TV remote will likely ruin it. These 3.6V batteries are for people who design their own electronics for that voltage, RC cars for example. Dncsky (talk) 19:00, 2 December 2012 (UTC)

And what's the point of making it round like an AAA battery? Couldn't they have used a flat cell-phone battery? OsmanRF34 (talk) 19:04, 2 December 2012 (UTC)

Allowing the use of AAA battery holders, I guess? I don't see any advantage in it myself. I would never buy these, since the risk of accidentally putting them in a $200 camera is too high. The vast majority of LiPo batteries are in the flat brick type. Google imaging "lipo pack" gets me the flat rectangular shapes for the first few pages.Dncsky (talk) 19:09, 2 December 2012 (UTC)

It seems as too much trouble just for keeping a minor piece. OsmanRF34 (talk) 19:28, 2 December 2012 (UTC)

They are usable in certain devices like some LED flashlights which can accept both types (although that isn't the primary reason they are made, the market is too small for that). Anyway lithium ion cylidrical cells of various sizes are commonly used in battery packs of various products like laptops, cordless drills, eletric cars, etc. The 18650 is I think the most common size but by no means the only one used. 10440 ('AAA' size) is often used in electronic cigarette. Note that many lithium ion chemistries including the most common lithium cobalt oxide are less flexible in manufacturing then the Lithium polymer battery chemistry so producing flat packs with them isn't so easy. (Anything which looks like a flat pack but has non polymer chemistry most likely just has a bunch of cylindrical cells.) AFAIK cylindrical cells are by far the most common production method for such non polymer chemistries. And when you aren't aiming for excellent packing like in phones, tablets and ultrabooks, the minor amount of wasted space isn't a big enough issue to be of concern. (There are other advantages of lithium polymer cells.) And lithium cobalt oxide still I think predominates among lithium ion chemistries (including polymer). So while lithium polymer batteries are rarely cylidrical, most lithium ion batteries produced are likely cylidrical. While you can purchase individual cells included protected ones (with a small protection circuit on top), this is a market which developed for certain specialist hobbyist uses. They aren't really intended for the end consumer, instead to be used in battery packs for devices. (And if your are using such lithium ion batteries, putting them in the wrong device and destroying the device should really only be a minor concern compared to the other precautions you have to take.) P.S. Generally speaking, it's best to avoid anyone who sells 'AA' or 'AAA' lithium ion cells. These would generally be called 14500 or 10440 by anyone who you should trust enough to buy such cells from. Nil Einne (talk) 20:18, 2 December 2012 (UTC)

what are the specific enthalpies of fusion of the chocolate phase transition temperatures?

I think it will be weak compared to water, but I wonder if the phase transition energy can make up for the lack of an precise thermometer when melting chocolate (while preserving the beta crystals) for use in dessert simply by watching where the temperature rise slows down. 128.143.1.238 (talk) 20:15, 2 December 2012 (UTC)

Can you back up and tell us exactly what you're trying to do with chocolate ? If trying to melt it without burning, I recommend a double boiler. If you want a mixture of solid and liquid chocolate, toss some chocolate chips in the dessert, along with the melted chocolate. StuRat (talk) 20:17, 2 December 2012 (UTC)