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September 4

Just been reading about SMART-1

Why are we humans so quick to crash high-speed objects into the surface of alien worlds without a single thought for the consequences in terms of it being seen as an act of aggression by potential natives?

You believe in the man in the moon, then? 8-?--Light current 00:13, 4 September 2006 (UTC)

Absence of evidence is not evidence of absence - maybe they're up there but they live deep underground. Maybe they think we suck already and this just confirms it. I think we've done some very foolish things when it comes to space exploration - like sending out probes containing data which would allow any potentially hostile alien species to pinpoint the exact location of our homeworld. --84.68.214.65 00:20, 4 September 2006 (UTC)

The Voyager/Pioneer probes are the least of our worries. Space is *big* and the chances of them being intercepted and picked up by a passing interstellar spacecraft are very, very, very small. Factor in the probabiliy that the aliens may be explorers, rather than conquerors and I wouldn't stress too much about that. We have, however been bleeding vast quantities of radio waves into space for the past century or so, basically turning the earth into a giant flashing 'something is going on here' beacon. Anyone/thing sentient and looking in the right direction within 100 LY or so already knows about us - and most probably knows *a lot* about us. --Kurt Shaped Box 00:33, 4 September 2006 (UTC)

Well theyd have to live deep underground to have survived all those impacts that the cratering shows has happened. And what do they live on, considering theres no water?--Light current 00:23, 4 September 2006 (UTC)

Maybe they live deep because it's warmer down there, nearer the core? Has it ever been proved that there's no water on the moon? --84.68.214.65 00:50, 4 September 2006 (UTC)

How did they get down there in the solid rock?--Light current 01:24, 4 September 2006 (UTC)

The onlyUsually, crashing is done by mistake. Everything else is simply a landing. AEuSoes1 01:27, 4 September 2006 (UTC)

Actually, the SMART-1 spacecraft appears to have been intentionally crashed into the moon at high speed so astronomers could examine the dust could. Wasn't something similar done with a probe ramming into Halley's Comet ? StuRat 01:37, 4 September 2006 (UTC)

The space mission I think you're talking about is Deep Impact, and the comet is 9P/Tempel. --Bowlhover 05:05, 4 September 2006 (UTC)

But that wouldnt bother the moon men at all surely: because they live under the surface! 8-)--Light current 01:49, 4 September 2006 (UTC)

Meteors hit the moon all the time, so the 'crash' would be a normal occurrence in that environment. (Then again, tropical cyclones are normal and they kill people - we'd be pretty upset if alien scientists created one artificially "just to see what it was like".) Peter Grey 02:07, 4 September 2006 (UTC)

Are you suggesting Hurricane Katrina was an attack on our homeland by an alien race that hates our democratic ideals? Lets launch a War on Extra-Terrestrial Terror, shall we? Rockpocket 06:15, 4 September 2006 (UTC)

As to the 'why', we don't think much about destroying life here on Earth at a massive scale, so 'we' don't realy give a shit. As to whether that's a nice thing to do, that depends on which chances you are willing to take. This reminds me of those Indian religious freaks who whipe the floor before them to prevent them stepping o bugs, which are, after all, also living beings. In the case of extraterrestrial life, the chances of that existing i na specific place are so slim that if we'd want to eliminate that risk, we couldn't do anything at all. Hell, we even accpet the death of half a million of our own kind each year for the sake of transportation. And those are deaths we know will happen and could even greatly reduce without much negative side-effects. And still we do it. As to whether it would be wise - would they retaliate? If we don't detect them they probably live on such a different level that they may not even know what hit them - jut like we think hurricanes are a natural phenomenen. DirkvdM 07:59, 5 September 2006 (UTC)

Beer-- why is it fattening?

Is it the alcohol, or the sugar/carbs, or both?--Light current 00:20, 4 September 2006 (UTC)

Beer is not really fattening at all. People tend to blame it on the beer when it is really the lifestyle that usually accompanies people who drink significant amounts of beer. i.e. sedentary jobless man that sit on the couch and watch tv all day lifestyle. — [Mac Davis] (talk) (Desk|Help me improve)

Are you really sure? I think its 200 cal /Imp pt It tends to make me put on weight.--Light current 01:14, 4 September 2006 (UTC)

The calorific content of drinks like vodka and rye come from acetate. Ethanol is converted to etanal and then acetic acid in a two step process in the body. Acetic acid is essentially a very short chain fatty acid (it doesnt have enough carbon to make it aliphatic, but it undergoes the same chemistry). As such alchohol has only slightly less biological energy content than vinegar. Also, the other ingredients in beer and other spirits, such as sugars and various organic matter, adds to the bottom line (and the waist line).Tuckerekcut 01:44, 4 September 2006 (UTC)

OK so its the carbs and the sugars that do most of the damage. But if you go for low sugar beer, it means it has more alcohol usually? And is the converse true?--Light current 01:52, 4 September 2006 (UTC)

Don't just blame the carbs--a shot of vodka (the regular stuff contains little more than ethanol and water) is ~50 calories. A pint of beer can run you 120-350 calories, depending on the brew. Mixers, of course, jack up the calorie content, too, as well as the greasy pub fare, and the following day's relative lack of activity (whilst battling a hangover) only makes the situation worse. Bottom line: total calories, in the form of sugars, fats, proteins or alcohol, is the most important number when watching one's diet, not the number of grams of carbs or fat. Net caloric balance is where it's at! Drink your beer! Just be sure to jog to the bar & back to help even things out! -- Scientizzle 02:35, 4 September 2006 (UTC)

• It's only fattening when you don't use the calories you take in. -131.211.210.11 07:11, 4 September 2006 (UTC)

See also beer belly.--Shantavira 07:11, 4 September 2006 (UTC)

It is also a result of the food that tends to be eaten with beer - e.g., peanuts, pizza... BenC7 10:59, 4 September 2006 (UTC)

Well I tend only to eat 1 packet of peanuts per session and no pizza etc!. I tend to eat before drinking to try to protect the organs--Light current 12:57, 4 September 2006 (UTC)

Beer is not fattening. However beer is extremely energy dense. So when you consume beer, you get to your daily requirement of energy very quickly. And so your other consumption of fatty food, quickly turn into belly fat. Remember, belly fat comes from other fatty food and not from beer. Ohanian 22:13, 4 September 2006 (UTC)

Thats not true contrary to popular belief you do not have to ingest fat to become fat, fat is simply stored energy, though comprised of chemicals, that may not be available from the beer, the energy that needs storing is obtained from the beer. And so beer does make you fat. Philc _T^E_C^I 20:22, 5 September 2006 (UTC)

OK but its the same difference!` I consume the energy fronm the beer instead of from my food which then goes to make fat? Makes sense--Light current 22:21, 4 September 2006 (UTC)

It's just like any other food. If you drink too much, then you will get fat. --Proficient 03:38, 6 September 2006 (UTC)

War between humans and another species on another planet in the solar system?

Suppose that our constant 'crashing of stuff into their planet' annoys them and they decide to do something about it and declare war - in what form would such a war take place?

If we assume that the alien species lives on a reasonably close planet (let's say Mars for the sake of argument) and has a similar level of technological development to us, then wouldn't the 'war' actually be a bit of a damp squib? Both they and we would be reduced to using rockets to launch bombs/heavy objects at each other's worlds, which would take several months to reach their targets, leaving plenty of time for them to be detected and diverted/destroyed in space.

Yep - interplanetary war would be pretty boring without manned warships and/or long-range laser cannons. :) --Kurt Shaped Box 00:47, 4 September 2006 (UTC)

(fell asleep, edit conflict) Most astrophysicists and astrobiologists say that any civilization advanced enough to be able to proceed in interstellar warfare would not. Kind of a age=wisdom=pacifism thing. — [Mac Davis] (talk) (Desk|Help me improve)

If the Martians were smart, they'd launch a small pod filled with a selection of interesting local bacteria/virii at the earth without even initiating contact with us to declare war. That way, we'd never see it coming. Billions dead if they chose the right bugs. --84.68.214.65 01:05, 4 September 2006 (UTC)

Despite the War of the Worlds book, microbes from one planet are unlikely to be effective against life forms on another. In order to be effective parasites, microbes must be adapted to their hosts. StuRat 01:20, 4 September 2006 (UTC)

We've been sending spacecraft to Mars for years. Most of them were probably covered with human DNA. If there are any Martains, they're probably aware of our genetic code. To the Martians, suddenly having a bunch of alien probes descending from the sky would seem very threatening indeed. It would only be common sense for them to examine the probes for evidence of their origin and for information about the species that sent them, just in case it became nescessary to defend themselves against an unknown enemy from space. Once you have DNA, you can figure out nasty things to do to the creatures that bear that DNA. --84.68.214.65 02:36, 4 September 2006 (UTC)

Really? You mean like the amazing success we - with "a similar level of technological development" - have had studying the DNA of influenza and the mosquito? And we know the fundamental basis of their genetic code and have them to test our "nasty things" out on. Rockpocke

Actually, all Martian probes are thoroughly scrubbed before liftoff so as to prevent contamination. It doesn't eliminate all microbes, but it certainly means that they're not "covered" in human DNA.AEuSoes1 21:05, 4 September 2006 (UTC)

t 06:10, 4 September 2006 (UTC)

And directed energy weapons like lasers would likely be ineffective because of the inverse square law. A more feasible scenario, perhaps, would be redirecting asteroids into collision courses with the Earth, particularly as ones made of ice make excellent nuclear rocket propellant. --Robert Merkel 01:28, 4 September 2006 (UTC)

Are you sure it would be so easy to detect a nuclear missile? Terrestrial warning systems look for launch plumes, and we've got it easy because the launches are so close. If Mars launched a ballistic missile at us, we wouldn't see the launch, especially if they were clever enough to do it on the far side of the planet. And a missile is orders of magnitude smaller than some of the asteroids we periodically discover in the neighborhood, so we wouldn't be able to see it once its motor went dark. Our only warning method would be to insert surveillance satellites into Mars orbit and hope they don't shoot them all down. Melchoir 02:06, 4 September 2006 (UTC)

Don't we have some sort of system already in place that routinely scans an area of space around the earth for objects and tracks them (radar based?)? I don't know what it's called but I've seen it on the news - they use it to locate and keep tabs on pieces of debris from our spacecraft that may be hazardous to future missions. Wouldn't that detect anything on a collision course with the planet? --Kurt Shaped Box 02:19, 4 September 2006 (UTC)

Yes, but anything coming from deep space at very high speed may not be detected in time to do anything about it (though of course the faster it goes, the more shielding you'd need to get it into the atmosphere, and the easier to detect it would become). However, one might suppose that missile defence technology might have improved somewhat by the time this becomes an issue. --Robert Merkel

What if the martians launch several nuclear bombs in quick succession, each one targeting a different place on Earth? I'll be surprised if anyone detects the bombs before they get extremely close (like within 1000 km), because SMART-1 was only magnitude 19 when it was orbiting the Moon. I'll be even more surprised if anybody can intercept an interplanetary spacecraft that doesn't want to be intercepted. There's hundreds of billions of metres between Earth and Mars, and a spacecraft is at most only several metres in size. --Bowlhover 04:21, 4 September 2006 (UTC)

We'll have at least enough time to launch the same sort of barrage back at them, ensuring ourselves the last laugh. Dead.  freshofftheufoΓΛĿЌ  05:44, 4 September 2006 (UTC)

I think it's clear at this point that our only self-defense option is to pre-emptively bomb the tar out of the planet as soon as possible. With any luck it'll send a strong message to the Asteroid Belt, too. Melchoir 07:09, 4 September 2006 (UTC)

No need to worry about the Asteroid Belt, the Martians already blasted them. :-) StuRat 08:22, 4 September 2006 (UTC)

So Astero was the solar system's version of Atlantis? DirkvdM 08:35, 5 September 2006 (UTC)

Probes that have been sent to other objects in space have to be sterilized (USA and USSR signed a treaty on that). Their biggest fear is to discover life on Mars... and then to be forever in doubt about whether or not it's not from our own planet. However, the Mars 2 and Mars 3 in 1971 from the USSR are said to have been poorly sterilized or simply not sterilized. But why would an alien race declare war upon an unknown (and possibly much stronger) species for just a dozen of probes on their entire planet?Evilbu 21:51, 4 September 2006 (UTC)

Imagine if alien probes of unknown origin started landing at various points on the earth's surface and regular intervals, taking readings/samples, then transmitting data offplanet. Provided that the governments of the world didn't manage to successfully cover it up, humanity would literally be *shitting* itself, due to fear of the unknown - "there is something out there that is interested in us and we don't know why!". You can bet that the military would have their best brains trying to figure out where the things were coming from, how they worked, what exactly they were doing, the technology involved in their manufacture, and coming up with possible strategies for defense of the planet in case the probes were only a prelude to something much bigger. A pre-emptive attack against the alien homeworld would certainly be an option raised at the meetings - "humanity must prevail at all costs", "violation of our territory by forces of unknown intent", "the enemy may walk amongst us at this very moment", "violence in self-defense", etc. --Kurt Shaped Box 23:43, 5 September 2006 (UTC)

In the history of mankind if two cultures met one easily overpowered the other because they were more technologically advanced. In the case of species from different planets, that would also likely be the case, just to a larger extent. So either they are very inferior to us, in which case they couldn't do anything, or they would be very superior to us, in which case they would have technology even we at the ref desk don't know about (assuming we're all humans - over the Internet you never know who's at the other end). So the question is unanswerable.

Another approach is to compare it to conflicts between different species here on Earth. We like to think we're superior to bacteria, but we rarely mange to stop them making us sick. So maybe the term 'superiority' doesn't apply if the species are too dissimilar, which they are likely to be in the case of species from differnt planets. Maybe we'd even be unaware of each other and consider what happened to be a natural disater or (more literally) an act of God. DirkvdM 08:35, 5 September 2006 (UTC)

"Most astrophysicists and astrobiologists say that any civilization advanced enough to be able to proceed in interstellar warfare would not. Kind of a age=wisdom=pacifism thing" — another example of why physical scientists don't make the best moralists or politicians. They also thought that after World War II, life would just be peaches and cream since nuclear power and nuclear weapons would ensure that everyone would learn to love their brother. Reality was a little messier. --Fastfission 14:36, 5 September 2006 (UTC)

Scientists thought that? I thought that was the politicians. Anyway, whoever came up with that plan had a very short memeory, because it was exactly such a standoff that led to WWI. DirkvdM 17:25, 6 September 2006 (UTC)

War between two different species on different planets would likely be over in short order, as one side would likely be far advanced beyond the other. Since the universe is billions of years old, the chance of encountering another civilization at a comparable level of technology (say, within 100 years of one another), is almost zero. StuRat 04:31, 10 September 2006 (UTC)

We only need one word here to discount ALL the above : SETI--Light current 04:46, 10 September 2006 (UTC)

Abingdon Island tortoise

Since this species is nearing extinction, and there is currently only a single individual left (a male named "Lonesome George"), could it be cloned to continue the species ? Also, if male turtles have an XY chromosome pair, I would think that two X's could be taken from two cells, and the Y discarded, to clone a female from the male. A female of a similar species could be drafted as a surrogate womb, and the embryo implanted surgically (sorry if this is the wrong terminology for an egg-laying species). Is there any reason this wouldn't work ? I do realize the lack of genetic diversity would not be ideal for the species, but think it would be infinitely better for the species than extinction. StuRat 01:12, 4 September 2006 (UTC)

The whole reason for sex (comments allowed) is to correct for genetic error. Sometimes the errors are good things, but mostly not. Even if there were both a male and a female, it would be difficult to keep the species going because of the lack of genetic diversity. Still, if they can clone dogs... --Zeizmic 01:30, 4 September 2006 (UTC)

I guess a good question here would be, have there been any reports of clones being able to give birth?  freshofftheufoΓΛĿЌ  05:40, 4 September 2006 (UTC)

Sure, Dolly the sheep had kids (well, lambs, actually), and plenty of cloned mice have reproduced. Rockpocket 05:45, 4 September 2006 (UTC)

I actually checked that article (and others) to make sure before I asked. There's no mention in it of her lamb, though I see now it mentions it in the picture. Bah.  freshofftheufoΓΛĿЌ  14:01, 4 September 2006 (UTC)

I would say your proposal is theoretically possible using current technology, though it would be very challenging and thus improbable. The inefficiency of cloning such a poorly studied animal notwithstanding, there are a few complicating factors. Harvesting different chromosomes from different cells during mitosis, then reconstituting them for successful nuclear injection could be tough. Using a difference species as a host would also complicate matters (consider Mitochondrial DNA). Overall, the track record for cloning of endangered species is not good. Rockpocket 06:02, 4 September 2006 (UTC)

I'm not sure we have the technical capability to extract single X chromosomes from XY pairs and use them to form XX pairs. --Lambiam^Talk 06:43, 4 September 2006 (UTC)

Picking two Xs from metaphase spreads and chucking them back together in a tube with the rest of the autosomes wouldn't be too difficult, i would have thought, with the right equipment. Making sure it viable for nuclear injection is a different kettle of fish, however. Rockpocket 07:10, 4 September 2006 (UTC)

How big is the turtle? Where does it come from? What is the cause for extinction? The best chance for this species is finding a remnant population. It would not work to clone the current turtle, cloning technology is not that advanced as to save a species in such a poor state (and I doubt any state). --liquidGhoul 06:49, 4 September 2006 (UTC)

It's a giant Galapagos Tortoise of the species Geochelone abingdoni. I believe that the sole remaining member of the species was moved to the Charles Darwin Research Station in the Galapagos Islands, after the remainder of the population was wiped out on Abingdon Island (one of the Galapagos), due to introduced species (such as rats, which ate their eggs). StuRat 08:10, 4 September 2006 (UTC)

Damn, then the chances of a remnant population are remote. I was hoping it was a small turtle from the Amazon or something. The Geochelone article doesn't mention this species, are you sure you have up-to-date taxonomy? --liquidGhoul 14:18, 4 September 2006 (UTC)

The article is at Lonesome George which says he is of a sub-species: Geochelone nigra abingdonii. Rmhermen 02:18, 5 September 2006 (UTC)

Upon reading that article, there sounds like there is some hope for finding another specimen. There are hundreds of Galapogos Tortoises around the world, some of them would predate the introduction of whatever killed them. Hell, Harriet was caught by Darwin, anything is possible. Genetic testing needs to be done to find another of the same subspecies. --liquidGhoul 07:34, 5 September 2006 (UTC)

At the very least, we can hope he lives a full life, giving researchers another 20 years or so to figure out if his sub-species can be cloned back into existance.  freshofftheufoΓΛĿЌ  06:26, 6 September 2006 (UTC)

Tracking down original references

Hi

I was wondering if there is a good way to find original references - the kind of reference that lets you say "X was discovered by Y in Z (Ref 1.). Any suggestions? If you happen to know, off the top of your head, how cytochalasin B, phloridzin, pholeretin or wartmannin were discovered,that information would be great! Thanks everyone!

Aaadddaaammm 06:37, 4 September 2006 (UTC)

yeah i've seen one of those things, its big and rectangular, and has "library" written on the front ;-) more seriously, you could probably find phloridzin and pholertin in a review somewhere, or on SciFinder if you are lucky enough to have access. Xcomradex 06:55, 4 September 2006 (UTC)

PubMed is your friend. If you query "cytochalasin" and look among the earliest references, you will find what you are looking for. This paper states:

The cytochalasins are metabolites of moulds that have been recently isolated by Dr W. B. Turner, who was also one of the group that described the chemistry of these compounds (Aldridge, Armstrong, Speake & Turner, 1967). Their special importance lies in their property of inhibiting cell division by blocking cytoplasmic cleavage. Such compounds are of value in the study of cellular function and these particular substances are unique in their ability to block cell division without preventing mitosis. Four cytochalasins have been isolated from culture filtrates: A and B from Helminthosporium dematioideum and C and D from Metarrhizium anisopliae.

The reference: ALDRIDGE, D. C, ARMSTRONG, J. J., SPEAKE, R. N. & TURNER, W. B. (1967). The cytochalasins, a new class of biologically active mould metabolites. Chem. Commun. 1, 26-2.

If you follow a similar process you should find the history of the other compounds also. Rockpocket 07:02, 4 September 2006 (UTC)

Awesome! Thanks very much for all your advice. I'll let you know how I get on. Aaadddaaammm 07:09, 4 September 2006 (UTC)

You can search google for databases of references I suppose. --Proficient 03:39, 6 September 2006 (UTC)

Scientist - Enrico Fermi

Did Enrico Fermi have a middle name? My son is doing a research project, and his teacher insists that the project not be turned in without the person's middle name. We have researched numerous sources and have not found a middle name for Enrico Fermi on any source. Thank you very much.

Enrico Neutrino Fermi? Your son's teacher needs a vacation. Not everyone has a middle name. The 'S' in Harry S. Truman, for instance, doesn't signify a middle name and was added for the sole purpose of having a middle initial. ---Sluzzelin 13:38, 4 September 2006 (UTC)

He/she already had one--it's summer vacation! And it still is for me. --Bowlhover 14:36, 4 September 2006 (UTC)

Doesnt look like he had a middle name--Light current 13:42, 4 September 2006 (UTC)

Wow. That S in Truman I didn't know about. Interesting. --Proficient 17:49, 4 September 2006 (UTC)

...Jesus H. Christ...(--Shantavira 18:08, 4 September 2006 (UTC))

Does anybody but me find it mildly irritating when a history book insists on giving full names for the individuals they mention, even when the individuals in question never used some of the names in public? ColinFine 20:16, 4 September 2006 (UTC)

The Harry S Truman thing is not the version I've heard. Both his grandfathers had names starting with S, and his parents couldn't decide which one of them to honour in his middle name so they chose just the initial. That way, both granddads could say that they were looked after. Neat solution to a tricky family problem. JackofOz 01:09, 5 September 2006 (UTC)

Then there's the fictional, although interesting, way of solving the problem as was shown on the Dick Van Dyke Show with their son, Ritchie "Rosebud" Petrie. The letters in "Rosebud" each stood for a seperate family member's name. Ritchie was bummed about having Rosebud as a middle name until Rob and Laura explained to him that he in fact had seven middle names. But back to the point, no, I don't know Fermi's middle name if he had one. And IMO, the teacher is being silly for putting forth such a requirement. Dismas|^(talk) 07:56, 5 September 2006 (UTC)

What an amazingly pedantic teacher. Nothing like making children focus in on the unnecessary details (middle names?) to make them miss the big picture and get the absolute wrong impression about scholarship. You should leave a note for them that even historians of science honestly don't give a damn about someone's middle name. We prefer first names because of the narrative form of history, but there is no strict reason to require them (E. Fermi gives enough information to work with, even Fermi would be fine if there was context given). We don't even REALLY care about specific dates in most cases—if you can remember something to the resolution of a quarter of a decade, that's usually enough. History is not about pedantic details or specific facts, it is about being able to combine lots of small understandings into larger understandings, to really understand the causes for things and the contexts of them. And Fermi didn't have a middle name, no. --Fastfission 14:44, 5 September 2006 (UTC)

While it may be unusual in the USA not to have a middle name, I don't think they are so common elsewhere.

They're not in many places. And even in the USA there are lots of people without middle names (I don't have one). --Fastfission 18:10, 6 September 2006 (UTC)

3d effects

Is it possible to create 3D efects with the help of the compouter screen?if not what extra hardware is required?

Origami — [Mac Davis] (talk) (Desk|Help me improve)

Are computer screens foldable now? - Rainwarrior 18:21, 4 September 2006 (UTC)

Well, yes. With 3D glasses of some sort, like the usual red blue ones combined with making a 3D scene in those colours on your screen. The Sega Master System had an interesting device for the game Space Harrier 3D which ran in synch with your screen, flipping one eye open and one eye closed at each frame and alternating display of the left and right views. - Rainwarrior 18:10, 4 September 2006 (UTC)

Also, there is the Stereogram or Autostereogram ("magic eye") kind of thing, which requires you to cross your eyes a little. That can also produce 3D effects. - Rainwarrior 18:21, 4 September 2006 (UTC)

LCD shutter glasses are a good way of getting full colour 3d images out of a computer screen. you need to buy the glasses and the sync box however, and you'll need to be using software that produces 3d data (eg. not wikipedia (yet)). Xcomradex 21:58, 4 September 2006 (UTC)

Philips has had 3D screens for quite some time now: [1]. --Lambiam^Talk 22:34, 4 September 2006 (UTC)

Maybe a higher end video card for producing graphic 3d effects. --Proficient 03:40, 6 September 2006 (UTC)

MAGLEV

is it possible to make a maglev such that only permanent magnets counteract the weight and side to side motion and only energized ones control its velocity so as to attain full eficiency?

Yes it is but it would take alot of magnets for the track. THats why its not done.--Light current 13:35, 4 September 2006 (UTC)

No, permanent magnets don't give stable levitation unless you have spin precession [2] If you try to construct a model maglev train, you'll find that it refuses to levitate no matter how many magnet positions you try. On the other hand, if the train is already moving fast before the Maglev is activated, then you can stablize things by placing the moving magnets near strips of conductors on the ground. "Inductive levitation" using permanent magnets does stablize things. --Wjbeaty 00:39, 9 September 2006 (UTC)

You could use small rubber wheels to stabilize the vehicle in a horizontal direction. But that solution does go against the questioners requirements.--Light current 17:57, 9 September 2006 (UTC)

Black-holes

What determines the schwarzchild radius of the black hole?

Its mass (only)--Light current 13:33, 4 September 2006 (UTC)

Just look at the formula given in the article. 2, G and c are all constants leaving m as the only variable.

bio project question

as i was looking 4 bio projects i came across this link , which described how to extract dna from green peas , im rather sceptical if this is true ,altough it looks like an university website, i think it is a prank. learn.genetics.utah.edu/units/activities/extraction/[3] my question is that is this experiment feasible , by that i mean when i tried it out i couldnt get the same results and i was wondering "is'nt dna soo small that it can't be seen with the naked eye?212.72.3.92 15:03, 4 September 2006 (UTC)

That's interesting. It looks real to me. When I did DNA extractions in intro bio in college, it was harder, but I think that's partly because we were using adult human cells, which as the FAQ for the Utah website explains, requires a centrifuge because the amount of DNA is smaller. An individual strand of DNA is tiny, but in principle there's no reason a bunch of strands stuck together wouldn't be big enough to see and handle. What I do wonder, though, is whether this procedure really separates out everything but nucleic acids themselves, or whether what you get at the end is something more like chromatin. (Also, we have an article on DNA extraction, but it needs work.) --Allen 16:34, 4 September 2006 (UTC)

(AFTER EDIT CONFLICT) Your link didnt seem to work for me, but my guess is that it described the rather simple marburg preparation of DNA by cold ethanol precipitation. Basically, if you put a whole lot of cells in your blender for a bit to crack them open (or alternatively use a chemical lysis method), and then put the resultant slush in to water, the DNA will dissolve in the water. If you then pour out a layer of very cold ethanol on top of the water so that there are two distinct phases, you can literally pull the DNA stands out of the water solution (and into the EtOH solution) with a scratched-up glass rod. The DNA is soluble in the water, but insoluble in the cold ethanol, so it will come out of solution as a sort of whitish clear stringy gunk. For the most part, this is DNA, with a bunch of other associated proteins. This is possible for two easily explainable reasons. First, the amount of DNA in a single cell is pretty large. If you were able to take the DNA out of a single eukaryotic cell and hold it as a piece of string, it would be about 2 meters long. It would only be a few atoms thick, and would break into millions of peices in the process, but you get the idea that it is pretty big nonetheless. To package this DNA into a cell takes many many recursive packaging mechanisms, and some of these are destroyed by the lysis/precipitation process, making the DNA more bulky than it would be in situ. The other thing to consider is that everything is made up of tiny things that are invisible to the naked eye. Even though a single copper molecule is too small to be detected, I can still see the penny in my hand. Similarly, even though a single (double) strand of DNA is invisible, when they are all stuck together, one can see them with the naked eye.Tuckerekcut 16:49, 4 September 2006 (UTC)

i had tried the experiment at home with rubbing alchohol ,not ethanol (i dont have ethanol at homeas u have mentioned could this be the reason why i was not able to get the desired results. forgive me for my naivety because i 'm just a ninth grader.i appriciate your efforts at tring to answer my query.212.72.3.109 17:32, 4 September 2006 (UTC)

by the way what is an edit clash???212.72.3.109 17:34, 4 September 2006 (UTC)

For the record, it is not a prank. After developing it as a workshop for the The Edinburgh International Science Festival [4] I have personally extracted more DNA from more peas than one would think humanly possible. See here for a picture of the workshop [5] (though not of me!). Its pretty crude, its smells bad, and you often get protein contamination, but you do get floccules of DNA that you can fish out. Rockpocket 17:51, 4 September 2006 (UTC)

as i had mentioned before i'm justa naive ninth grader , could u be kind enough to enlightened me with the method u used 9 (not meant to be sarcastic in nature)and what is an edit clash ,(did 2 wikieditors clash sword s ???)212.72.8.224 18:08, 4 September 2006 (UTC)

An edit conflict is when two or more people try to edit a section or article at the same time. The second person to click 'Save page' has to do some sorting out to write what they want. Skittle 21:52, 4 September 2006 (UTC)

Also, I did almost the exact procedure described on that page in class. We used onions blended with washing up liquid, and it worked. Skittle 21:56, 4 September 2006 (UTC)

I remember passing someone at the Science Fair a few years ago who did a project like that. It worked for them, I guess. I've noticed, though, that almost none of those do-it-yourself science projects ever work for me, no matter how simple. In theory, I think I could create an antigravity system just by throwing something off a balcony. Black Carrot 06:06, 5 September 2006 (UTC)

I'll let you into a secret, the DNA from peas hardly ever worked for us at our workshop either. Its difficult getting the peas digested up enough in the timespan you have to hold the attention of the kids. In addition, you need the alcohol to be superchilled, which we used to struggle to do in the absence of a proper freezer. So what we would do is extract shedloads of DNA back in the lab using better reagents, then spike the kids reactions with the pre-extracted DNA, which they could take home with them. If one kid was being a little shit (a regular occurance) then we would not spike their extraction and tell them they obviously didn't do it correctly. Those moments used to make my day. Rockpocket 06:56, 6 September 2006 (UTC)

but can i use rubbing alchohol instead of ethanol????212.72.2.238 16:09, 6 September 2006 (UTC)

Yes you can. But make sure its as cold as possible, by putting in in a freezer beforehand. Rockpocket 20:36, 6 September 2006 (UTC)

i want to be adoctor

hi am 21 years girl ia am studying genteics engenering in jordan and my dream in this life to be adoctor in some day i wana ask if i can continue medicine after i finsh gentics and how many years i need and what i could do to know all the information that i need because i lessen that someone finish genetics and know he study medicine not from the first he continue i want to know if this true or not please help me because i need this help

am marwa abulel am have israelian nationality

I think this differs per country so your best option would be asking your student career counceler. They should be able to tell you exactly what's possible with your genetics degree and what you would need to become a doctor. - Dammit 16:23, 4 September 2006 (UTC)

You will be much better off if you can get out of Jordan for studying and practicing medicine. — [Mac Davis] (talk) (Desk|Help me improve)

How did you know that (practicing medicine in Jordan sucks)? ≈Eh-Steve 16:59, 4 September 2006 (UTC)

Where do you want to become a doctor? --Proficient 17:51, 4 September 2006 (UTC)

I guess you could do anything you want. I just figured you would be better off in Europe, Asia, or North America. — [Mac Davis] (talk) (Desk|Help me improve)

Psst, Jordan is in Asia ;-) - Dammit 22:48, 4 September 2006 (UTC)

If you are Jewish, you'd best get out of Jordan before you are murdered by terrorists. However, I'm assuming you're an Israeli Arab studying in Jordan, in which case you might be safe, except from random killings by terrorists. If you would like to work as a doctor in an English speaking country, you need to improve your English quite a bit. I suggest finishing your studies in an English speaking country, so you will pick up the language more quickly. I expect genetic engineers to mesh more closely with doctors in the coming years, with gene therapy becoming a major form of treatment in the future. So, your background in genetic engineering should be quite helpful. StuRat 03:44, 5 September 2006 (UTC)

To add to that, not only is it a good idea to have solid English skills if you want to work as a doctor in an English speaking country, but it is also an important (and extremely valuable) skill enabling you to communicate medical knowledge from the English speaking world (which is a good portion of it) into the world that speaks your native language. Even if you end up working as a doctor in Jordan, your English skills will be invaluable as you follow in the footsteps of reasearchers worldwide. Also, good luck!  freshofftheufoΓΛĿЌ  14:10, 5 September 2006 (UTC)

There is no need to get a medical degree in another country. Just on my floor of the hospital, there are doctors who got their degrees from: Nigeria, Syria, Israel, Greece, Norway, Canada, China, Tanzania (sp?), and the U.S. of course. Ones that recently left came from Panama, Australia, and Japan. Now, there is one advanatage to getting a degree in the U.S. - it can be basically free. The U.S. is very stupid about student loans. You can come to the U.S. and take out huge student loans to pay for medical school. Then, when you are done, leave the U.S. and never come back. If you don't come back, you never have to pay the loan back. The idea, as far as I can tell, is that the government thinks that if you spend a few years here you will want to stay (and pay taxes) for the rest of your life. --Kainaw ^(talk) 14:18, 5 September 2006 (UTC)

Are you sure they spent none of their University time in an English speaking country? I have a friend who became a doctor (MD) in China (Shanghai), who lives in Japan now and was finding it extremely hard to find work (he still doesn't work as a doctor), though it might be easier in somewhere a bit more accepting of other cultures. He speaks fluent Japanese and excellent English, at least when it comes to medical stuff. The reason why he came to Japan in the first place is that apparently MDs in Shanghai make less than taxi drivers! Hurray for communism!  freshofftheufoΓΛĿЌ  06:20, 6 September 2006 (UTC)

They got their degrees in their home countries. Most of them, I figured out the country from the degree (doctors feel a need to have an "I Love Me" wall with all their degrees and awards on it). Others, such as Syria, I had to ask because I couldn't make out the degree. It isn't hard for a doctor to get a job in the U.S. if they are willing to take a lower paying one in the south. Congress passed an act at least 10 years ago to speed such doctors through immigration and get them a working visa. I'm in Charleston, SC - so it is considered the south. That is probably why there are so few American doctors working here. --Kainaw ^(talk) 19:39, 6 September 2006 (UTC)

Incidentally, here is your question translated into proper English (or as near as I can get to it):

I want to be a doctor.

Hi, I am a 21 year old woman. I am studying genetic engineering in Jordan and my dream in life is to be a doctor someday. I want to ask if I can continue my medical studies after I finish genetics, how many additional years of study I will need and what I need to do to learn everything that I will need to know. I heard of someone who finished studying genetics and know he studied medicine afterwards. I want to know if this is feasible for me or not. Please help me, because I need your assistance. StuRat 04:53, 6 September 2006 (UTC)

Death of Jupiter

The article on Jupiter points out that it expends more heat than it recieves from the Sun through the Kelvin-Helmholtz mechanism. My knowledge of thermodynamics isn't great but I do know that if it is losing more energy than it's gaining then it will eventually run out. What will happen to Jupiter and its sattelites as it cools down and "dies"? What impact will it have on the rest of the Solar System? Will the same thing happen to Saturn?

Regards, Gallaghp 16:49, 4 September 2006 (UTC)

Are the energy inputs from collisions with asteroids, and the moons gravitational pulls (atmospheric tides I guess you'd call them) enough to balance the system.

Also even if the planet was radiating more heat wouldn't the Kelvin-Helmholtz mechanism cause it to shrink until its surface area was small enough for it to be radiating no more energy than it is recieving, and balance the system that way. Instead of your proposal that the mechanism continues indefinately until the death of the planet. Philc _T^E_C^I 17:21, 4 September 2006 (UTC)

A good point. I was mainly concerned with Jupiter's influence over the surrounding planets and moons, such as with it's magnetosphere (am I right in thinking it's the biggest "thing" in the solar system?) which would certainly diminish along with the planet. I know it's composed of different elements but after sufficient shrinkage is it possible that it might behave more like the outer gas giants, Uranus and Neptune? Gallaghp 21:21, 4 September 2006 (UTC)

Hm, its magnetosphere is pretty colossal so I should imagine it wouldnt be shrinking to exclude its sattelites very soon, or ever, if the thing about it stabalising is correct. About it being the biggest thingin the solar system, it is (i'll spare you the perdanticities of the sun, and its related areas of effect). I might me getting out of my depth, as my knowledge of planet behaviours is not to good, but how does jupiter behave differently? Philc _T^E_C^I 20:18, 5 September 2006 (UTC)

Far planets have nothing to do with dying suns, they seem to be very cold already, I dunno if some more cooling may change their nor our way of life. -- DLL ^{.. T} 19:49, 4 September 2006 (UTC)

Um, i think you may have misunderstood the question, hes referring to the planet dying, not its sun. Philc _T^E_C^I 20:17, 4 September 2006 (UTC)

rubella virus

i know that the rubella virus lives in the respiratory tract, but does anyone know what happens to the respiratory tract whilst it is infected??

so if anyone knows anything, please tell!! luvSammie hero 19:39, 4 September 2006 (UTC)

While the virus resides in the respiratory tract, the patient is asymptomatic. This is called the incubation period. So apparently the virus has no direct ill effects on the respiratory tract. It is only when the virus enters the bloodstream that symptoms appear, none of which have to do with respiration, except perhaps for a runny nose. --Lambiam^Talk 21:38, 4 September 2006 (UTC)

Editing problem?

I want to edit the section above on this page on complex carbohydrate, yet all I am given to edit is the Rubella virus question above. What's happening?

I get that a lot too, just refresh and try again, it usually works for me. Philc _T^E_C^I 20:33, 4 September 2006 (UTC)

Seconded. Anyone know what the underlying problem is? Does it just happen when you click an out-of-date "edit" link? Because I can recall times when refreshing wasn't enough. Melchoir 20:34, 4 September 2006 (UTC)

Could be an issue with transcluding, I can't exactly copy content at bot speed, so there is a bit of lag, but I've also been hitting a lot of server lag today, so that's probably more likely to be it--VectorPotential^{RD NEEDS A BOT (-:} 21:24, 4 September 2006 (UTC)

Usually what has happened is that – between the time you loaded the page and the time that you clicked edit – a section had been inserted or removed above the section you wanted to edit. Someone may have removed a duplicate section, added a new subsection, or a bot could have archived some of the older entries. Look at URL in your browser's address bar after you click one of the section edit links; the last part of it will be section=21 or something similar. Sections are numbered consecutively down the page; if one is added or removed, you'll end up editing the wrong section. Refreshing/reloading the page will usually fix the problem. TenOfAllTrades(talk) 21:41, 4 September 2006 (UTC)

Thanks, seems to work OK now.

Seems strange that the problem happens to a lot of people. --Proficient 03:41, 6 September 2006 (UTC)

How do the unintelligent think?

Although there has been over millenia a lot of effort put in to describe how the intelligent think, for example logic, nobody seems to care how the unintelligent reach their conclusions.

My question is prompted by what I observed recently on a long bus journey. I overheard a middle-aged woman talking to what I expect was her grandchild. She had been smoking heavily before boarding the bus. I heard her say that the sweets her grandson had were full of "good things", for example sugar; that you needed to eat a little sugar (as if it was some kind of vitamin or essential nutrient), but that eating too much sugar makes you thirsty (perhaps some warped misunderstanding of diabetes). I wonder how she could have reached these conclusions? Credibility? Inattention? Sentiment? What?

Understanding how the less gifted think would help us more priveledged people improve our thinking, and also be of use for advertising and propaganda. 62.253.52.76 21:28, 4 September 2006 (UTC)

Ill-informed? CAn be confused with lack of intelligence.--Light current 21:33, 4 September 2006 (UTC)

Your base assumption that fallacious thinking has gone unstudied is simply wrong. I wonder how you might have reached that conclusion? Ignorance? Melchoir 21:35, 4 September 2006 (UTC)

While I agree that mistakes in intelligent thinking in the form of fallacy has been studied, I am doubtful that unintelligent thinking has been - can you provide some evidence or links please?

Prospect theory. --best, kevin [kzollman][talk] 22:23, 4 September 2006 (UTC)

Obviously ignorance is studied and well understood, how else do you explain TV commercials? Why do you think people get paid millions to come up with the definitive SuperBowl beer commercial?--VectorPotential^{RD NEEDS A BOT (-:} 21:40, 4 September 2006 (UTC)

Hang on... beer commercials can be hilarious! Surely they're also accurate depictions of reality? Melchoir 21:42, 4 September 2006 (UTC)

I think your belief that this woman was unintelligent, at best, did not follow logically from the available information, and at worst, was elitist and judgmental. Sugar, a source of calories, is indeed a good thing nutritionally when not taken in excess. She might have been speaking in a sense other than nutritionally, as well, with a meaning along the lines of "sweets are good for the soul." Sugar is hygroscopic, so too much definitely makes you thirsty. In fact, for rehydration, highly sugared beverages such as soda are not favored. You should really examine your assumptions before reaching such radical conclusions about other people's intelligence. --Ginkgo100 ^{talk · e@} 21:47, 4 September 2006 (UTC)

While a packet of sugar sitting on the table may be hydroscopic, when sugar is digested I believe it releases water. (Sidenote - never try to drink blood when you're dying of thirst in a desert - the protein in it uses up more water in its digestion).

A classic example of Ignoratio elenchi or maybe Ad hominem.

Maybe she was lieing to the kid so that he wouldnt eat all of his sweets at once. Philc _T^E_C^I 00:36, 5 September 2006 (UTC)

I have a very closely related question. How do some presume, without any empirical evidence whatsoever, that they are more intelligent than others? What is the precise neurological malfunction causing this phenomenon? More specifically, what is the precise mechanism that serves to block their limited minds from considering that they may actually not know as much as they believe to know? In fact Socrates, one of the greatest thinkers humanity has ever produced, would clearly have no choice but to regard these individuals as the lowest of morons, for they, of all people, are the least bit in touch with their own ignorance. In the words of Socrates, true wisdom is only attained when one recognizes that one knows absolutely nothing. Loomis 02:31, 5 September 2006 (UTC)

I have also wondered why the less intelligent are also less concientious. According to scientists the answer is that both concientiousness and the executive functions of intelligence are controlled by the frontal lobes of the brain, so the two go together.

Is wisdom the same as intellignece? I would say not--Light current 02:44, 5 September 2006 (UTC)

Inductive reasoning is one type of "illogical" thought process which has been studied extensively. Also, if you look under fallacy and logical fallacy, you will see there are a many examples of logic errors which have also been studied thoroughly. StuRat 03:25, 5 September 2006 (UTC)

What does smoking have to do with sugar or intelligence? Black Carrot 05:44, 5 September 2006 (UTC)

If someone chooses to smoke, that either shows they don't care about their health, or that they have concluded all the evidence showing the health problems caused by smoking is wrong, in which case they are idiots. There are many, however, who are addicted, so don't really "choose" to smoke, but rather wish to stop, but are unable to do so. StuRat 04:37, 6 September 2006 (UTC)

THe implication seems to be that because the woman was smoking 'heavily' (although Im not sure how that could have been deduced since the questioner was on the bus, and the woman at the bus stop) It therefore meant she had a low intelligence.Maybe shes not wise to smoke-- but thats not low intelligence (I believe Uncle Albert smoked a pipe)--Light current 05:48, 5 September 2006 (UTC)

You've somehow decided that I was on the bus - I wonder how you reached that conclusion? In fact we were both queueing for the bus for a long time. I was trying to stay upwind of her to avoid her smoke plume.

I decided because of this sentence: what I observed recently on a long bus journey. You dont take bus journeys standing in a queue and you didnt day you were queing. So I assumed reasonably you were on the bus.

--Light current 08:51, 5 September 2006 (UTC)

I think the process the unintelligent use to reach their conclusions is different from the cold rationality of the intelligent. I think people form their ideas from sentiment and ego protection. For example, if a fellow student is much wealthier than onself, then you would tend to think he is an unpleasent person. I've noticed that the less intelligent spend nearly all of their time socialising with each other and hence have no time left to do any work - this may be due to a functional necessity to stop such petty jealousies arrising and thus leading to bullying. Most of them also definately think that matters relating to dominance in the here and now are far more important than anything else in the world.

Could there be such a thing as a logic of the unintelligent? This would require consistency. If you put a bunch of unintelligent people together, will they come up with a way of communicating that is devoid of logic as we know it but has a consistency of its own? Take insects, for example. They are way off the scale (at the bottom end) when it comes to human inteligence tests, yet they have functioning societies. Do they therefore have a logic of their own (that we humans don't understand)? DirkvdM 08:58, 5 September 2006 (UTC)

I think there's a lot of sense in that - ie the unintelligent believe in a 'set of truths' that are unrelated - ie no calculus is permitted on the different objects, so contradictions may exist and obvious conclusions are not drawn. Quite a pleasing logic from a mathematical POV however. Rentwa 09:56, 5 September 2006 (UTC)

What do you mean by unintelligent? I'm quite interested in abnormal psychology when it's actually morbid (especially autism), but if you're talking about average human moronicness it's just a hotch-potch of ignorance, poor culture, political degradation, drudgery etc. In Saturday's London Times there was an interview with a man who became prominent in homeless activism. He said (which I thought perceptive if a little damning) 'My family wasn't just poor, they thought poor and lived poor.' I remember a man in a pub telling me that 'if it was printed in the papers it had to be true', and no rational explanation of why this was false could shake his quaint view that there was a law (probably something to do with Magna Carta or Habeus Corpus) that journalists were honour bound to check every fact before commiting it to print. Or maybe he thought there was something special about the newsprint that made untruths vanish from the page, or maybe he had simply never thought about it for himself. I have a thousand similar jolly tales of working class life oop north, maybe I should write a book? Rentwa 09:08, 5 September 2006 (UTC)

It would seem that conclusions are reached based on emotion rather than logic. There is a theory - cannot remember the exact terms - but it was something like Festinger's congruency theory.

That's Festinger's theory of cognitive dissonance. --Lambiam^Talk 04:58, 6 September 2006 (UTC)

Self-expectation is very important in determining one's success or otherwise in life, perhaps more important than qualifications. That would explain why the children of the rich get rich themselves.

Is this why I'm editing wikipedia and not working on my book? :) Rentwa 10:00, 5 September 2006 (UTC)

You too, huh. We should form a "Society of Putative Writers Who've Become Temporarily* Diverted by Wikipedia". (*like, for years at a time). JackofOz 12:08, 5 September 2006 (UTC)

I prefer to think of myself as a "punitive writer". :-) StuRat 04:40, 6 September 2006 (UTC)

Oddly enough (and not to make any assumptions since Stu obviously understands 'putative/punitive') I think punning humour is often regarded as a low form of wit because it's available to those who have limited vocabularies (only requiring phonetic understanding), and is often used as a defense mechanism to cover their ignorance. Rentwa 09:45, 6 September 2006 (UTC)

I'm not sure I agree with that. Punning requires a greater degree of linguistic and lexical knowledge, and often historical knowledge, than many other forms of humour. It requires an appreciation of subtle nuances, of homophones (there's that word again, Stu), and not least, the music of language. Puns are very under-rated, IMO. JackofOz 10:51, 6 September 2006 (UTC)

Stu is a "punnitive writer". :-( Lambiam^Talk 10:55, 6 September 2006 (UTC)

Tell me about it. I usually bear the brunt of it. But rest assured, his puny wit doesn't get to me (damn, too many pointers in that link - let me try another one). Let the punic wars continue. (Is that enough history for you, Jack?) DirkvdM 17:37, 6 September 2006 (UTC)

On with the Punic wars, yes ... but, as for my "puny wit", I consider my wit to be rather elephantine. :-) StuRat 07:07, 7 September 2006 (UTC)

Better to have historical knowledge than hysterical knowledge! Get it! No? Alright, lemme try again. Being an anglophone and not a homophone, perhaps I don't quite get Jack's humour! Get it! Yes! No? Oh well, I tried. :-)Loomis 22:01, 6 September 2006 (UTC)

Huh? Either you are too smart for me or .... DirkvdM 08:13, 7 September 2006 (UTC)

OK, Loomis, let me get this straight (oops!). If francophone means speaking the language of the French, and anglophone means speaking the language of the English, then homophone must mean speaking the language of .... (you fill in the blanks).  :--) JackofOz 13:19, 7 September 2006 (UTC)

And that is the gay dope. :) DirkvdM 06:52, 8 September 2006 (UTC)

Thanks for your use of the ellipse, Dirk. That was very kind and civil of you and I appreciate it (no sarcasm intended). As for my post, that was just a failed, pathetic attempt on my part to grasp the sheer genius that are puns (sarcasm intended!).

As for the homophone thing, English seems to be full of annoying misnomers. Take "Indians" for example being used to describe indigenous Americans. How the hell did that whopper of a snafu made over 500 years ago survive to this date? Indians?! Even referring to people from India itself as "Indians" is a bit screwed up. The terms "India" and "Indian" are derived from the Indus river. And guess where the Indus river is located today? In India? No! In Pakistan! So even by referring to Indians from India as "Indians" you're using a rather mild misnomer. But to refer to aboriginal Americans as "Indians", what you're actually doing is naming them after a river in Pakistan! Now THAT'S a stretch if I've ever seen one!

There are seemingly hundreds of these. One that bugs me is the word "homophobia". If one were completely unfamiliar with the phenomenon of gay-bashing or any other sort of discrimination against gays, one would likely just look to its etymology. Alright..."homo", well that's Greek for "sameness." And "phobia," well that's greek for "fear". Put the two together and what you've got is a word that seems to describe a "fear of sameness". Fear of sameness? What the hell could that mean? Well look up the word "xeno" in Greek and it seems to describe the English word "different" or "foreign," or "other." So from a purely etymological perspective, while "xenophobia" would seem to describe a fear of those that are different from you, "homophobia" would seem to apply to a fear of those that are the same as you. It would follow, then, that "homophobia" would more appropriately apply to, say, a French person who is afraid of French people, or a Jew who is afraid of Jews, or even a gay person who is afraid of gay people. Of course in real life it has a completely different meaning. So, for the sake of practicality let's just take for granted that the prefix "homo" doesn't refer to "sameness", but refers to "homosexuality". I still take issue with the term. I think "anti-homosexual" would be a lot more appropriate, not "homophobic". Any psychologist will tell you that a "phobia" is no more than an irrational, pathological, yet innocent fear of something. If you're arachnophobic you're afraid of spiders. It doesn't make you a "bad" person and it doesn't even make your fear a "bad" thing. It just makes you a person who has an irrational fear and, in most cases, one who would like to get rid of that irrational fear. So are "homophobes" simply kind decent folk who have an irrational, pathological fear of homosexuals? One that they'd love to rid themselves of with proper psychological guidance? Of course not! "Homophobes" are bigots. They don't have an "innocent but irrational" fear of homosexuals, on the contrary, their hatred is quite rationalized in their minds. They're bigots, pure and simple, who should be shunned for their hateful beliefs, not "innocent phobics" who'd like nothing better than to rid themselves of their irrational fears. Calling these people "homophobes" just sugarcoats the whole thing, and I really don't like that.

But as they say, you can't fight city hall. For centuries, those who hate Jews have come to be known as "anti-Semites". Another silly misnomer. Yes, Jews are Semites, but so are Arabs. And in today's political climate, the biggest "anti-Semites" (i.e. Jew-Haters) are Semites themselves. The whole thing is absurd. Anyway, I realize I drifted onto a whole tangent of my own here, as the original question had something to do with how dumb people think. Well, maybe my little rant here wasn't all that inappropriate. If anyone thinks what I'm saying is moronic, then this whole rant may actually be completely apropos. Here you've got a perfect illustration of how a dumb person thinks :--) In any case, Stu, now it's your turn to scold me and tell me that this whole discussion should have been moved to the language RefDesk :--). Peace to all of you. Loomis 22:13, 10 September 2006 (UTC)

Apples and Saliva

I've noticed that my saliva becomes unusally viscous after eating an apple. This only happens with apples and not other fruits that I eat. What causes this? --Burbster 22:43, 4 September 2006 (UTC)

Anything with a lot of sugar causes an increase in salavia viscosity for me. Maybe that is it. As for the mechanism, I don't know. — [Mac Davis] (talk) (Desk|Help me improve)

I don't know the cause, but when i was a student i used to work in a lab that did genetic testing for cystic fibrosis. We used to get buccal swabs from which i would extract DNA. We found that, when the patient had recently eaten an apple (specifically), we would really struggle to get good quality DNA from the swab. I always assumed it was related to the acidity of the apple. I wonder if these two phenomena are related. Rockpocket 06:12, 5 September 2006 (UTC)

That's very interesting. I should probably look further into this. Thanks anyway guys. --Burbster 15:27, 6 September 2006 (UTC)

How natural cherry flavor is made

I would like to know how natural cherry flavor is made. Signed: "Nacherl"

steam distillation? Xcomradex 23:07, 4 September 2006 (UTC)

If it's natural, my best guess is that it's made from cherries. What am I missing here? Loomis 02:07, 5 September 2006 (UTC)

I think Nacherl is asking how they get the natural cherry flavor into the product. My guess would be they mash the cherries into juice, then add the juice to the mixture, be it candy, soda, or medicine. Hyenaste ^(tell) 02:10, 5 September 2006 (UTC)

no, i would say they distill the flavour molecules away from the pulp, to stop other components of the pulp interfering at a later stage. So i'd say distilled from cherries (or some other plant). Xcomradex 03:12, 5 September 2006 (UTC)

If you don't know the answer, then please do not substitute any random guess as a reply. --Lambiam^Talk 08:14, 5 September 2006 (UTC)

I'm not sure how you meant natural, so I may be missing the point if the question but esters are used to flavour most things. Cherry flavour can be made from ethyl heptanoate, geranyl butyrate, methyl benzyl acetate and terpenyl butyrate according to the article. Philc _T^E_C^I 10:51, 5 September 2006 (UTC)

"Natural flavor" does not mean it actually comes from cherries. It means that it is the same chemicals as are in "artificial flavors" but has been synthesized in a "natural" way (there is a specific legal definition of this; see Flavor#Flavorants). They probably have nothing to do with actual cherries. "Natural" flavors are preferred by food companies because they sell better; they have otherwise no differences from "artificial" flavors. --Fastfission 14:54, 5 September 2006 (UTC)

If I'm reading that definition right (it is somewhat ambiguous), it does say that natural cherry flavorant needs to be made from cherries, or at least from some "spice, fruit or fruit juice, vegetable or vegetable juice, edible yeast, herb, [etc.]". In particular, it says a natural flavorant needs to be an "essential oil, oleoresin, essence or extractive, protein hydrolysate, distillate, or any product of roasting, heating or enzymolysis", which rather restricts the preparation methods allowed. —Ilmari Karonen (talk) 20:43, 5 September 2006 (UTC)

That seems a little tricky about the natural/artificial flavors. --Proficient 03:44, 6 September 2006 (UTC)

This specific thing actually did come up in a legal fight some years ago. I don't remember all the details. But as I recall, one company sued another over the way the second company made "natural cherry flavor" (that is, benzaldehyde) from bitter almonds. The thing that struck me was, the first company also made its natural cherry flavor from bitter almonds, just in an allegedly more "natural" way. --Trovatore 03:50, 6 September 2006 (UTC)

Hey, everyone, this is the first time I've used Wikipedia, so thank you for all the good information. --Nacherl

How does human body maintain ph?

I assume that if our bodies did not maintain a constant ph, our metabolisms would go awry.

How does it do this? If you eat acid foods, does your urine become more accidic?

Is the average long term ph of the food you eat the same as your body ph? If not, why not?

Could you kill yourself by just eating acid foods all the time?

Thanks.

There are several buffer systems, of which the most important is bicarbonate, and several compensatory mechanisms (metabolic and respiratory). For further explanation you can consult a medical text on acid/base balance, or our articles on acidosis, alkalosis, metabolic acidosis, respiratory acidosis, metabolic alkalosis, respiratory alkalosis. We may have a more centralized discussion somewhere in Wikipedia? - Nunh-huh 00:01, 5 September 2006 (UTC)

negative feedback, through homeostasis, by use of blood hormones. Philc _T^E_C^I 00:34, 5 September 2006 (UTC)

Which hormone did you have in mind? Hormones have next to nothing to do with regulating acid base balance. - Nunh-huh 01:19, 5 September 2006 (UTC)

Vasopressin would affect blood ion concentrations and aldosterone is important to regulate sodium and potassium balance in the blood. -- Scientizzle 03:58, 5 September 2006 (UTC)

Yes, and the question was about pH! - Nunh-huh 04:24, 5 September 2006 (UTC)

Sorry, I should have been more clear. Hormonal alteration of ion balances is acheived by modulating ion & water transport activity in the kidney nephrons. Aldosterone stimulates H⁺ secretion, thereby raising the pH. Vasopressin will concentrate the urine, therefore also making the blood more dilute, too, and potentially reducing acidosis or alkalosis. -- Scientizzle 05:32, 5 September 2006 (UTC)

But neither of those effects are primarily mechanisms for regulating pH - they are epiphenomena. The primary mechanisms for regulating pH are those which I named in my answer. The questioner should not think that "blood hormones" are particularly important in regulating acid/base balance, because they're not. - Nunh-huh 06:14, 5 September 2006 (UTC)

I don't disagree with you one iota. I was simply giving examples of hormones that have non-zero effects on blood pH. The important point: HCO₃ and other buffers provide the immediate control over influx of acids and bases, and hormones (on a much slower time-scale) can modulate the buffer system. -- Scientizzle 02:02, 6 September 2006 (UTC)

farking edit conflicts: i remember a story about one of the early (german?) researchers (i forget the name) into blood pH eating 1 kg quantities of ammonium chloride and studying the effect, for those of you unfamilar with ammonium chloride, it is an acid with a "biting taste" (apparently) and an unpleasant ammonia smell. so i guess you can eat quite a bit of acid before fatally pushing the buffer equilibrium too far. Xcomradex 00:40, 5 September 2006 (UTC)

Ammonium chloride (also known as salmiak) is a salt, and not particularly acidic, though the evaporation of ammonia may make its solutions slightly so. Mind you, if you eat a lot of a highly acidic or alkaline substance, the immediate effect (assuming it's not acidic or alkaline enough to irritate or even corrode tissue directly) will be to change the pH of your stomach content, leading to indigestion. —Ilmari Karonen (talk) 05:33, 5 September 2006 (UTC)

Ammonium chloride is indeed a salt, but it is classically used for acidification of the urine. It has been used, for example, to test for distal renal tubular acidosis. - Nunh-huh 06:14, 5 September 2006 (UTC)

September 5

Discovering an alien probe

Let's say an alien robotic probe parachutes down to a suburban area in the U.S. Someone discovers it. What will happen next? Also, ideally, what should happen next? --Bowlhover 01:09, 5 September 2006 (UTC)

Our government would take it away. And convince that entire suburban area that the said event never took place. Russian F 01:39, 5 September 2006 (UTC)

George Bush would invade a country that wasn't involved. Peter Grey 02:10, 5 September 2006 (UTC)

Seriously, although I'm not very happy with the U.S. government, I don't think they're hiding anything about alien probes. They are hiding information about U.F.O.s, but those U.F.O.s are probably either natural phenomena or machines built by humans. --Bowlhover 03:35, 5 September 2006 (UTC)

The reason you don't think the government is hiding information about alien probes is that you do not believe there have been any alien probes. Now, if I were to tell you there have been several, and you believe me, would you still think the government isn't hiding the information? --Lambiam^Talk 08:12, 5 September 2006 (UTC)

No, but I don't believe that there have been any alien probes. How hard is it to expose the truth if many people took pictures of it? It would be hard to confiscate all of the evidence, wouldn't it? --Bowlhover 03:39, 6 September 2006 (UTC)

Why specifically the US? Is this meant as a question about US politics (as Peter took it to be)?

Given Peter's example, the person who discovers it should idealy inform international organisations first, before the US government finds out. The UN would be a good choice, but they would not have a mandate to claim it. No extra-USian governmental organisation would. So may be he should infomr a private enterprise and get them to transport it to a neutral country. But I don't know which enterprise would be willing or able and what constitutes a neutral country anyway. New Zealand? DirkvdM 09:08, 5 September 2006 (UTC)

Tell anyone except your own government first - that way there's less chance that they'd just spirit the thing away, never to be seen again. The UN, international news agencies, the Pope, anyone with a bit of clout. --Kurt Shaped Box 23:53, 5 September 2006 (UTC)

Am I the only one who doesn't think the authorities would cover it up? At least not after they confirmed for themselves what it was.  freshofftheufoΓΛĿЌ  13:49, 5 September 2006 (UTC)

Bill Clinton seemed absolutely thrilled to think that discovery of alien life had been done under his term (ALH84001). I think that the assumption that American politicians would be happier hushing something like that up does not take into account the political benefits of being the first president to announce contact with another civilization. --Fastfission 14:49, 5 September 2006 (UTC)

In a sense, the probe would have the initiative. If it can communicate, and has a sufficiently advanced artificial intelligence, then we'd be very interested in what it had to say; if it was damaged, then all we could do would be to analyze it. If it said it would only talk to the UN, we probably wouldn't argue. There would be a conflict between quarantining it (it could have extraterrestrial bacteria, or it could have become radioactive, etc.) and displaying to the media, given that there would be a natural skepticism about the discovery, especially if it had not previously be detected moving through our solar system. If it appeared in US territory, given that the US has the resources to examine it, they would probably handle it through military channels (because there could be a legitimate worry that it would be dangerous). A cover-up would probably be impossible. Peter Grey 17:59, 5 September 2006 (UTC)

Is it really a good idea to carry the probe away immediately? The aliens who sent it don't even know there's life on Earth, and if somebody takes the probe away, they'll think their mission failed.

I picked the U.S. as the landing place because its people know (relatively) a lot about science. If I picked some small community in Africa, where half of the residents are illiterate, they'll think it's a gift from God or something. And no, this is not a question about U.S. politics. It's about how we should let the aliens know that life exists on Earth. --Bowlhover 03:39, 6 September 2006 (UTC)

Everyone here is making a mistake. You're taking the viewpoint of the aliens in "knowing" an alien probe has landed. Now a human would have no such knowledge. Suppose the thing landed on your own street. From your point of view a 'thing' (not a probe) has 'appeared' on the ground (and not landed). Unless the landing was witnessed, and unless it's huge, it would appear to be some kid's weird toy. How did it get there? Where did it come from? If not a toy, then it would look just like a hoax or like a publicity stunt, or like some weird project built by subscribers from [makezine.com]. Wouldn't it take quite a bit to convince you that it wasn't just a toy or a hoax? That said, I would predict that if it's small enough, one of the neighbors would not recognize it as a probe, but would see it as valuable and unclaimed, and therefore steal it. Then perhaps they'd diddle with it for awhile, then dump it in their backyard or cellar and eventually forget about it. Which leads to this conclusion: several alien probes may have already landed, and they're sitting forgotten in barns, cellars, or weed-filled back yards right this minute.  :) --Wjbeaty 00:23, 9 September 2006 (UTC)

Why are you assuming the alien probe lets itself be confiscated and examined? --Proficient 03:46, 6 September 2006 (UTC)

If a probe lands in a an inhabited area with artificial structures, it is probably not trying to go undetected. Of course, maybe it's builders just think differently. Peter Grey 13:24, 6 September 2006 (UTC)

Kurt, the pope? He'd certainly hush it up. What are the chances the aliens are catholic? And what would the catholics make of that?

Why do these things always land in the US in hollywood movies? It has only 2% of the Earth's surface. Then again, the martians in War of the worlds landed in England, which even has less than a promille of the surface. A Luxemburgian SciFi writer would have a serious credibility problem. :) DirkvdM 17:50, 6 September 2006 (UTC)

You seem to be assuming they just land somewhere at random (and you even include landing on water, apparently). What if they have been observing us and decide to land in the "center of power". They might well decide that is the US now, or England back in H. G. Wells' day. StuRat 09:53, 7 September 2006 (UTC)

If conquering the Earth is the goal (as was teh case in War of the Worlds) then it wouldn't be smart to land in the lion's den. Especially if that lion is armed to the teeth. Landing on an ocean would make most sense if the goal is to establish a base first. The oceans are barely observed (a problem for meteorologists) and one can go underwater for even better cover. But even if they don't know how to build (u)boats and have to land on ... ehm ... land, a remote piece of land would make a better choice. Like Siberia or the Sahara. The US has some deserts too, but is the most paranoid country on Earth when it comes to attacks (with reason, but that's a different issue), si that would be the most likely place to be detected. So, to come back to the original question, if aliens land in the US they are either incredibly stupid or want to be detected. DirkvdM 18:50, 7 September 2006 (UTC)

If they had an overwhelming military superiority, though, it would make sense to defeat the biggest threat first. This seems to be the case (or, at least, the aliens think it's the case) in most movies I see. StuRat 04:22, 10 September 2006 (UTC)

If you're paranoid with good reason, well...then...you're not paranoid. The definition of paranoia is the irrational fear that people are out to get you. If people are indeed out to get you, and you're worried about it, then by definition you're not paranoid. Rather, you're just very rationally concerned. Loomis 21:07, 10 September 2006 (UTC)

separation of chemical compounds

How could you separate barium sulfate from ammonium chloride?

How could you separate barium chloride from calcium sulfate?

How could you separate tellurium dioxide from silicon dioxide?

Undesguised homework again? Choose some of the properties and use the most appropriate ones to aid separation.--Light current 02:00, 5 September 2006 (UTC)

i'm guessing reading isn't his/her strong point... Xcomradex 03:03, 5 September 2006 (UTC)

Mine neither--Light current 05:30, 5 September 2006 (UTC)

no for you it's spelling, unless it's all a clever desguise... ;-) (no harm intended). Xcomradex 08:07, 5 September 2006 (UTC)

I prefer to call it finger trouble! THe keys are too close on my keyboard 8-)--Light current 08:24, 5 September 2006 (UTC)

• Salts like the ones you describe are usually separated using precipitation reactions. You need to figure out the rest. - Mgm|^(talk) 10:53, 5 September 2006 (UTC)

Sulfates of the Alkaline Earth elements are generally insoluble in water. Chlorides are usually very soluble in water. I do not have a clue about the last one, both are very insoluble in water, but maybe a solvent exists which is good for one but not the other.

For the third pair, one of them is twice as dense as than the other. See Silicon dioxide and Tellurium dioxide. Of course, I'd use a mortar and pestle and my firing oven, but that's just me... -- Fuzzyeric 00:06, 6 September 2006 (UTC)

California Moss Genus/Species

Can someone tell me the taxonomical binomial nomenclature of that common, general greenish moss that is found all over rocks and such on the southern West Coast? Thanks so much, ChowderInopa 01:58, 5 September 2006 (UTC)

You mean what its called?--Light current 02:04, 5 September 2006 (UTC)

Yes, I mean the scientific name. ChowderInopa 02:38, 5 September 2006 (UTC)

Can you say something more about its appearance? Are these damp habitats? Are you sure it is not lichen? --Lambiam^Talk 07:59, 5 September 2006 (UTC)

The southern west coast of what? Oops, missed the header. DirkvdM 09:09, 5 September 2006 (UTC)

satellite imagery maps

I need to know where to look for the satellite imagery maps. I want to see what my home looks like from above and the locations around my home. Please show me how to get there on wikipedia. Floyd — Preceding unsigned comment added by 68.119.96.36 (talk • contribs)

I'm too tired to do the whole 'build a satellite' launcher routine, fun as it would be. Google is your friend. Go there, and punch in your ZIP/postcode. If necessary, switch from map to satellite view. --Mnemeson 02:21, 5 September 2006 (UTC)

for even more google, try Google Earth. its great. Xcomradex 03:05, 5 September 2006 (UTC)

Do you smell burning toast?

Hey, could anyone settle a debate for me? My friend doesn't believe that smelling burnt toast, when there is no environmental source of the smell, could be a sign of a stroke. Is it a common occurrence, something that happens rarely, or just a myth? Thanks in advance for your input. --Dimblethum 02:52, 5 September 2006 (UTC)

It could be a sign that you suffered a stroke, and then tried to toast the same slice of bread 10 times, after which it would smell rather burnt. :-) StuRat 03:02, 5 September 2006 (UTC)

It may be a symptom of a stroke. (See for example this case study.) It may also be indicative of a brain tumour (it is sometimes a sign of brain metastases in advanced cancer), or of some neurological problem, or it could just be a passing random olfactory hallucination. An odour of 'strawberries' is also reported by some individuals. Some people have also reported a burnt toast smell immediately before a seizure or migraine. TenOfAllTrades(talk) 03:04, 5 September 2006 (UTC)

Burning rubber is another one. George Gershwin had this symptom before they diagnosed his brain tumour. Any disturbance to the proper functioning of the brain can produce visual, auditory, olfactory, gustatory, or kinesthetic perceptions of external phenomena that do not objectively exist. JackofOz 07:13, 5 September 2006 (UTC)

So are synesthetics in constant threat of a stroke? DirkvdM 09:19, 5 September 2006 (UTC)

I think you can work that one out yourself, Dirk. JackofOz 12:04, 5 September 2006 (UTC)

burnt toast

I've heard that burnt toast has the same calories as regular toast. I believe it has less, but negligably less compared to our caloric intake.

what are th e facts?

Jasbutal 03:52, 5 September 2006 (UTC)

That sounds reasonable, but I have no facts. I would guess that if a piece of burnt toast is still palatable enough to swallow, then it can't be too badly burnt after all, and its interior is still perfectly nutritious. Melchoir 03:58, 5 September 2006 (UTC)

I dont see how it can have the same, since some of the bread has been reduced to pure carbon. THat is how you tell the calorific value of food- you burn it in pure oxygen till theres only ash Food_energy#Measuring_food_energy.--Light current 05:09, 5 September 2006 (UTC)

I'd say both statements are probably correct; there isn't necessarily any contradiction between "(approximately) same" and "negligibly less". (Or course, that depends on how burned the toast is — if you burn it all the way down to water, carbon dioxide and ash, it won't have any caloric value left.) —Ilmari Karonen (talk) 05:23, 5 September 2006 (UTC)

Exactly. So how many calories would you like in your toast this morning Sir?--Light current 05:27, 5 September 2006 (UTC)

As dry as it may seem, regular toast still contains a considerable amount of water. The overheating that causes the toast to burn also evaporates some of the water. The net effect on the calories per unit weight may initially be an increase. --Lambiam^Talk 07:51, 5 September 2006 (UTC)

Yes that is why toast racks are used I believe- to let the toast dry out and not go all soggy.--Light current 08:10, 5 September 2006 (UTC)

Very interesting. --Proficient 03:48, 6 September 2006 (UTC)

Blindness and circadian rhythm

I recall reading about an experiment where some college students were locked in a windowless suite of rooms without a clock, and were invited to sleep whenever they wished. Many of them began sleeping at unusual times that wouldn't map well to the 24-hour day. However, when they were made aware of the sun's progress, their sleeping patterns began to approximate the day-night cycle. Is anyone else aware of this study? My question is this: do the sleeping habits of blind people tend to be independent of the sun? Presumably the only non-visual distinction between day and night would be one of temperature, and if the person remained inside in a climate-controlled environment, this would not matter. Long question short, is there any record of blind people having trouble casually (i.e. without having to put special effort into it) distinguishing night from day, and experiencing sleeping problems as a result? Is it plausible? I'm not talking about people with jobs and schedules, but people who might not pay close attention to clocks, such as people in hospitals or retirement homes. Bhumiya (said/done) 05:00, 5 September 2006 (UTC)

I don't believe your assumption that blind people are less aware of the time of day is correct. They have a variety of ways to check the time, from audio watches, to radio and TV broadcasts, to periodic events, like church bells ringing, etc. While it's true that a blind person in a coma in a hospital would be unaware of the passage of time, the same is also true of a sighted person in a coma. StuRat 07:12, 5 September 2006 (UTC)

Well, that's true, but I didn't mention comas. I only meant patients in general, who would have little to do but lie in bed. Bhumiya (said/done) 03:56, 6 September 2006 (UTC)

I believe that a blind person, in any condition short of a coma, would still be aware of the approximate time of day. StuRat 06:44, 7 September 2006 (UTC)

Years ago I remember seeing a tv doc about people living in windowless rooms without any time cues. They started to live on a 25 hour cycle, which curiously enough is the same length of day as on MARS!!

I think blind people would take their cues from tv, radio, alarm clocks, and other people.

But I think the intresting question is whether you can force your body to physiologically adapt to an arbitrary night/day cycle without the usual help you get from light, which causes your brain to secrete a variety of transmitters that entrain your circadian rhythm. I guess it would depend on what the exact cause of the blindness is. Nrets 16:56, 5 September 2006 (UTC)

I think that if anyone is not aware of the sun's changing, then they will have an internal clock that keeps changing and getting off. --Proficient 03:50, 6 September 2006 (UTC)

I once heard or read, but cannot confirm, that there are two common circadian patterns among humans, one of which is about 25 hours long, the other 32 hours or something like that. Bhumiya (said/done) 03:56, 6 September 2006 (UTC)

I remember hearing, but I also can't remember where, about recent research suggesting that there was some kind of problem with the research that came up with the 25 hour figure, and that more recent research suggests that the free-running cycle in humans is closer to 24 hours. (Our article on circadian rhythm sure needs work. We also have an article on Free-running sleep, but it seems to use the term to mean sleep that's unaffected by artificial rhythms, while in biology I think "free-running" refers to rhythms unaffected by anything external to the organism, natural or not.) --Allen 04:15, 6 September 2006 (UTC)

I think that we may be proceeding with a false assumption. I also remember hearing, from at least two sources, that the effect of light affecting circadian rythm is not purely visual. The effect of light upon one's skin can also serve as a cue. Even a blind person would have light shining on his/her skin, and this would seem to be an additional cue as to whether it's daytime or nighttime. Loomis 12:46, 7 September 2006 (UTC)

Mantle

Has there ever been an attempt at diging down through the crust to reach the mantle?

Yes I think it was called the Mohole project.--Light current 05:29, 5 September 2006 (UTC)

...which failed. The Japanese are going to have another go at this next year. See Chikyu Hakken.--Shantavira 06:06, 5 September 2006 (UTC)

At the risk of asking a silly question, wouldn't that cause magma to rise and cause a volcano? I suppose one would have to make sure to drill at the right spot, where the is no magma chamber. Did I just answer my own question? DirkvdM 09:32, 5 September 2006 (UTC)

If you'll forgive me for attempting to answer a question that I myself was about to ask: I believe any area that would be in danger of spurting would be doing so already, or at least would be showing some sort of bulge. Any low/thin area of sea bed should conceivably be on top of a relatively inactive section of magma.  freshofftheufoΓΛĿЌ  13:38, 5 September 2006 (UTC)

And yes, I guess you did ^_^  freshofftheufoΓΛĿЌ  13:40, 5 September 2006 (UTC)

Awesome.

At the risk of accusation of adding rubbish comments, I would say I tend to agree with the bulging hypothesis--Light current 00:03, 6 September 2006 (UTC).

Ah, so that explains the eruptions. This the kind of rubbish comment you were talking about? DirkvdM 09:21, 6 September 2006 (UTC)

Small writing - should it be allowed?

Hmmm, I now realise you may not have been thinking about the bulging and eruptions I was thinking of .... DirkvdM 19:16, 6 September 2006 (UTC)

Yeah man, that was pretty embarrasing. Maybe if you delete it now, no one will notice.  freshofftheufoΓΛĿЌ  14:13, 7 September 2006 (UTC)

Or maybe if I make myself really really small ... can't get it smaller than 0, though. DirkvdM 18:55, 7 September 2006 (UTC)

Psst! do you think you will go unnoticed by writng this small? Some people here have eagle eyes you know!

Damn, someone gave this a really big header. We'll be spotted any moment now. DirkvdM 06:55, 8 September 2006 (UTC)

Yeah but this is a legitimate discussion of the use of small writing on the Ref desks. And it takes up less room than big writing.--Light current 07:04, 8 September 2006 (UTC)

Is it Bad to run PC without proper Earth supply?

Hi friends!...I've been using pc for a couple of years without supplying earth because in our block we have no earth connection to ground...Now is it ok to proceed so or need to give earth?..however I can feel some earth(mild current shock) passing on me whenever I touch the metal parts in the PC because of no earth..I know why this is,because of the returning current has no path way to ground an hence circulating in the cabinet and in all the metal parts..Some say it will affect HDD or RAM soon...Is it so?..and is it okay to proceed as usual?...or should I take immediate action for earthing?.But until now I haven't gotten any faults in my PC...Please help friends...My advance thanks

I'd say if you are feeling any shock at all, then yes, the computer should be grounded, immediately. (It's also a good idea, in any case.) :-) StuRat 07:06, 5 September 2006 (UTC)

Do you mean you should be grounded? What naughty things have you been upto this time? DirkvdM 09:36, 5 September 2006 (UTC)

"One should be grounded in reality" ... you ought to try it sometime ! :-) StuRat 01:58, 6 September 2006 (UTC)

If you have an external AC adapter, you should not be in danger of a serious shock, as it only delivers a low voltage (say 16V) to your PC. With an internal power supply, you might get electrocuted, which is generally not recommended. You could use a voltage meter to check if any metal parts carry an unsafe voltage compared to ground. --Lambiam^Talk 07:34, 5 September 2006 (UTC)

Thanks...I recieve some mild shock inside the PC only...Maximum voltage of the SMPS (Internal Power Supply output only) is 12V.So I guess there shouldn't be risk of high volage shock..but say the current rating is as high as 22A..The shock is mild only which is bearable though..My suspect is that if it's gonna affect my hardware parts?...I haven't recieved any complaints yet since from the time I bought I've been using without earthing...

Unless this equipment is double insulated (which I doubt, if it has a metal case), it is not only undesirable, it is downright dangerous and even LETHAL. THe fact you are getting shocks should tell you this. Switch off NOW, unplug from the socket, and contact a reliable electricain immediately!--Light current 08:05, 5 September 2006 (UTC)

Isn't that last advise a bit over the top? I've connected my computer case to an unpainted part of a radiator. Shouldn't that suffice? DirkvdM 09:36, 5 September 2006 (UTC)

No I dont think so. The BS regualtions state that Any Class 1 equpt should have all exposed conductive materials solidly earthed to the mains earth. Furthermore, there is a requirment that the loop resitance of live and earth shall be less than a certain amount so that the protective device is activated. --Light current 13:22, 5 September 2006 (UTC)

The equipment is double insulated (wire casing and psu casing) until it gets to the PSU and after that the voltage and current are whacked down from hairburning to finger tickling levels. so... people should be alright. Philc _T^E_C^I 10:44, 5 September 2006 (UTC)

In the UK I'm sure it would be illegal to have an electricity supply without an earth. But in America......

Still though, most household items dont have an earth, only ones with metal casing do, often they dont even have an earth pin, just a dud plastic one. Philc _T^E_C^I 10:44, 5 September 2006 (UTC)

I thing no one here has grasped exactly what I meant.I told you that the shock is not severe at all and it's just a leakage current due to the absence of proper earthing....The shock is bearable only...This shock wasn't observed when I checked it with my friend's house(He has earth in his house)since the PC operates with only 12V,how can it be so lethal and dangerous?..The cause why I recieve shock should be b'coz of leakage current circulating over the panels....It's seems no threat to humans though I suspect if it can be for the Hardware in my PC...If I touch the RAM,HDD it gives me this mild shock still...I really wonder when it will die hard...

This is stray voltage, as in this ref [6] It is very bad for cows. For people, it is not that good, especially if one day you are touching the case, and the water tap at the same time. You could put on a Residual-current device, or attempt to ground with a pipe. Most likely, there is a short in the computer that will limit its life. --Zeizmic 12:28, 5 September 2006 (UTC)

If youre feeling anything, it means that electric current is flowing from your computer metalwork through your bod and down to earth. THis means that the casing is live and dangerous. I advise you get it looked at! It really sounds as if this eqpt needsan earth. Check the handbook!

THe danger comes from the fact that mains voltages are entering the power supply. If the power supply is faulty, the case can become live. If the case is not earthed, protective devices (fuses, breakers) will not operate and you are in danger of ELECTROCUTION! Please take it from me. I have experience in this field.--Light current 13:31, 5 September 2006 (UTC)

The usual phenomenon with lots of big SMPSs is that there's a big RFI filter right at the mains power input; the filter blocks both RFI coming into the supply from the line and power supply hash going back out onto the power line. This filter usually takes the form of an LC "pi" filter on both the neutral (return) and hot (live) lines, usually with pretty substantial capacitors to the safety ground which, of course, is then connected to the chassis of the SMPS and whatever the SMPS itself is then bolted to. If the safety ground lead isn't so hot or is outright disconnected, you find that the capacitors make a voltage divider that puts the chassis at about 50% of the line (mains) voltage, and most people can definitely feel that ;-). Whether or not it's enough current to cause a hazard depends on the design of the specific power supply, but I think that regulatory agencies won't permit such large capacitors in the pi filters as to allow a dangerous amount of leakage for ordinary equippment that is expected to be used in a residential or office environment.

At Digital Equipment Corporation (my former employer), because our high-current pi filters had larger capacitors, we had to put warning labels on the power cords of our big commercial equipment warning folks that there was enough leakage capacitance that the safety ground had to be connected to earth; otherwise, unsafe amounts of AC leakage current would occur.

So that's one aspect of the problem: ordinary operation. Then there's the question of the various faults that can occur. I'm in complete agreement with the folks above that because certain faults could possibly lead to mains power being connected to the chassis, it's essential that things that have a safety ground pin on their line cord (mains flex) either be connected to an actual safety ground or be connected to the mains through a residual-current device (ground fault circuit interrupter/GFCI). Those two methods are the only way to assure your safety if a worst-case fault occurs in the power supply.

And then, of course, there's the question of electrostatic discharge and your computer's ability to resist that. Absent an intended safety ground, you may find that your computer isn't able to resist static discharge (for example, sparks from you) to the degree that you would have expected. But that only endangers your data and your computer, not you.

Atlant 00:03, 6 September 2006 (UTC)

Dont forget, Atlant, that we dont know the line voltage at this users house. If its only 120V ac and it is a line RFI filter thing, then he gets 60 vac to ground. However in countries with 240 vac, the volts are definately 'feelable'. The current limiting of course depends upon the capacitor reactance. I had this very problem with an intermittent earth wire (inside the scope case) on a 485 Tek scope - wondered what the hell was going on!--Light current 00:22, 6 September 2006 (UTC)

Where do you live, where your entire block isn't electrically grounded?! That floating city from Star Trek? Clarityfiend 04:18, 6 September 2006 (UTC)

In the US it would be very strange for the whole block to share an earth ground. Each house should have its own 8 foot (or so) copper rod driven into the ground to provide earth ground. Failing that, you should be able to tie the ground wire of the electrical system to a cold water pipe. Of course if the electrical is old enough, there won't be a ground wire run to every outlet, but its easy enough to ground any new circuits you install. -- 69.106.48.1 05:00, 6 September 2006 (UTC)

(Off on a tangent...) In the US, you actually do share earth grounds. Ordinary household split phase utility distribution systems are usually constructed with a grounded neutral, grounded at many points including every distribution step-down transformer. Then, the neutral is grounded one more time at your house's service entrance. All this redendancy of grounding helps assure that the neutral really does stay within a very few volts of the true earth ground potential.

Atlant 23:56, 6 September 2006 (UTC)

Make sure electrical modifications are done by a qualified electrician. The ground wire for any new socket must run from the circuit breaker panel or fuse box. It is improper to go around connecting the ground terminal of an outlet to any random cold water pipe near the outlet. One reason for this is that the circuit impedance may be too high to pop a circuit breaker quickly to prevent electricution. The impedance is lower when the ground return is in the same cable as the outgoing hot wire, and higher when it travels a different path. Also the pipe you connect to may be isolated from the main ground by a dielectric fitting, and so a phase to ground short in an appliance would only energize say your bathroom faucet, creating a new shock hazard. Edison 15:06, 6 September 2006 (UTC)

Memory and aging

Can you please find me information about Barnes' 1997 experiment with rats. he tested how the rat's age affected memory.

thank you.

Google is your friend. Just search for your key terms such as: Barnes 1997 experiment rats memory. Dismas|^(talk) 07:44, 5 September 2006 (UTC)

you won't have luck with rats around here, there are no experts. but if you were to ask about barnes's earlier experiments with seagulls... Xcomradex 08:11, 5 September 2006 (UTC)

ARRRGH--Light current 08:26, 5 September 2006 (UTC)

No expert on rats ? That's not fair ! StuRat 23:16, 5 September 2006 (UTC)

Phloretin, phloridzin

According to the literature, both of these chemicals seem to inhibit glucose transport into cells. -idzin has a glucose molecule attached, where -etin is exactly the same molecule, just missing this glucose moiety. Does anyone have any insight into why this is, as it's quite counter-intuitive. I would expect -idzin to be an "invincible substrate" kind of thing, but then how does -etin work?

Thank you very much Aaadddaaammm 09:04, 5 September 2006 (UTC)

i guess it shows you the aglycone of phloretin is active piece, not the glucose bit. phloretin is a protein kinase C inhibitor, as well as an inhibitor of a number of transporters, including the glucose transporters. so that's where the effect comes form, it's just coincidence phloridzin has glucose on it. [7]. Xcomradex 10:18, 5 September 2006 (UTC)

How processors work ?

How the control unit of a CPU/PROCESSOR/MICROPROCESSOR works ? I've cearch in wikipedia and in other sites but they all provide me the information that microprocessors are made of transistors ; several electronic gates like and,or,not are described . But i want to know the process by which microprocessors control an electronic device using 0&1 as input . How transistors are placed in a microprocessor ? How the increasing number of transistor in a processor increase the processing speed of a microprocessor ? What's the minimum number of transistor that can form a microprocessor (it will be better if a circuit is drawn showing positions of transistors and explanation of where the circuit takes input and where the output)? Explain the working procedure of microprocessor by an example of mp3 player .

Does the above question sound like a homework assignment? Explain your answer with reference to the above text :PPikiwedian 09:52, 5 September 2006 (UTC)

The information is all in Wikipedia. I doubt whether anyone is going to give you a succinct answer to all your questions here as they involve several different disciplines. Have you looked at transistor, digital circuit, logic gate, and microprocessor? --Shantavira 10:28, 5 September 2006 (UTC)

CPUs may be made out of logic gates, but that's like saying DNA is made out of atoms. It's not an explanation.

Here's a popular question: "Where is the little man who actually does the work?" Often that little guy is a binary counter which can turns on various output lines depending on the current count. The "little man" can also be a ROM and a parallel latch, where the data bits from the ROM are held in the latch and sent back to the ROM's address lines. In any case, the 'brain' of the CPU is a state machine. You may be more familiar with a common state-machine everyone uses: the dial on a washing machine. In fact, it should be possible to use an old washing machine dial as the central mechanism in a very crude electromechanical computer. (First thing to do would be to change the gearing so that the dial can be rotated fairly rapidly!) --Wjbeaty 20:03, 6 September 2006 (UTC)

Yes,though most of us know it better,we can't keep typing everything in here.It's practically impossible..My suggestion is to have a good book knowledge first....But we can give some basics what we can....First you must know the internal architechure of any basics Microporcessor atleast like 8085,8086 (x86 series basics is good).Try google search for the architechure 1st.It's quite easy to learn...Your question is multi-directional and it confuses me where to begin with...I'll drop some basics that should be useful...later check the Wikipedia or in google, in detail for learning about transistors in digital circuit and logic circuits that control devices as Shantavira said. 1)Any control unit uses multiplexers(MUX) and DMUX to send signals to the multiple periperals with reduced pins in IC.This helps in reducing the CPU size...These are usually done with the aid of gate combinations eg.,NAND or XOR etc....So to enable a peripheral,all it needs to send is a low or high signal like(READ or WRITE or READY or ACKN or etc)which is an information that can be obtained from reading the instruction stored in RAM with respect to the CPU clock.It has Address Bus and Data Bus inside...Upon executing each instruction step by step,your CPU(Program Counter\Stepper)places the next intruction address and starts fetchin the data from RAM.This process keeps on cycling according to your program....Upon this,instruction is something which has information about the operation type and the Data for that operation written in Machine Language.This is depicted as opcode(operation type) and operand(operation Data) which is a standard format of any instruction. For eg.,

      "INSTRUCTION = (OPCODE+OPERAND)"
                   =    "OUT FFh".

Here Out is the OPCODE and FFh is the peripheral address.The data to be sent to this device is stored in one of the data registers.Each instruction is stored in different address in your RAM.So All you gotta do is to write your desire instructions and then store it in RAM and begin executing..There you go.....Here The opcode tells the CPU to send the data in it's default register to the device which is in the address 0xff location....Upon executing this instruction,the CPU 1st reads the Opcode only in it's first clock cycle and then it understands the meaning of that operation and it generates control signal accordingly and clears the pathway to this address and sends the data by reading the Operand in its next clock cycle.By decoding opcode,CPU can determine it's action and it generates the control signal...Provided the CPU has many supporting registers(unit for storing data) for ALU operation....so it can store frequent data up there and refer to it..Note it's only the instruction of your program that makes the CPU to geneate control signals...Your electronic device when connceted to CPU,automatically it must be given as address so that it can be identified uniquely like IP address...as we looked the instructions,just choose the appropriate insturction for controlling the device....For more and detailed information about the generation of control signals,please check out your text books... 2)About the transistors,the ON and OFF state is the only means by which we can store any data digitally.perhaps if one transistor is required for just storing one bit(0 or 1),then 8 transistors are required for 8-bit and so on..Technically they no longer call it as 8 transistor,but simply as Register and they give names like reg A or reg EA or so on....So a 32 bit CPU like any pentium processors has registers of 32-bit lengh,but it can have 16 or 8 bit units still...More the amount of registers,more number of intructions can be executed and stored and hence maintaining parallelism....so more number of transistor,more powerful and faster your CPU is. 3)Since 4004 is the 1st microporcessor(to my knowledge) which just had about 2300 transistors with operating clock of 108 KhHz...It's only a 4-bit processor(Data bus only) compared to any 32/64 bit processor now...So I guess atleast 2300 number of transistors might be required for making a CPU with reduced size(I'm not though sure) 4)Similarly for playing music CD's there are always some default instructions which are stored in your player's memory permanant.They are nothing other than the one that tells your procesor about seeking the CD with spin up and spin down command and also how to control the laser movement in readind the CD directory..You can learn more about this by experimenting with Microprocessor controlled Stepper motor.Once locked to the track in the disc,it keeps the trace and starts moving horizontally hence giving the data(music) from the pits....Apart from this,all user interfaces(Buttons,LCD,etc) are all controlled by microporcessor(Microcontroller is used these days instead) only...Regarding MP3 or other formats of audio,comp/decomp and all kinda processing is done by DSPs only...Besides these there are lot to know....I hope this Basics should help somehow..(Correct me if I'm wrong)

You may also want to read [8] and subpages. (You probably need some knowledge of informatics or electric engineering to understand that.) – b_jonas 21:38, 5 September 2006 (UTC)

Smelling things that aren't there

Ever since high school I have had periods of time where I would occasionally smell what I can most closely call cigarette smoke (although not quite). The whole thing seems to be psychological and fairly random (I'm not sure of any specific triggers), I can go months at a time without smelling it. and I have a friend who has had a similar phenomenon since her uncle died of lung cancer. Strangely enough, another friend has the same situation but with "hospital smell." I don't like cigarette smell and the latter friend doesn't like the smell of hospitals. Is there a term for this? Am I going to die? AEuSoes1 10:03, 5 September 2006 (UTC)

• Well, I doubt you're dying, but according to Wikipedia:Reference_desk/Science#Do you smell burning toast? it might be a symptom of a stroke. I don't know what smelling things without a source is called, but if you worry about dying, you should see your doctor about it. - Mgm|^(talk) 10:50, 5 September 2006 (UTC)

That's what made me think of this, but I'm not smelling it constantly, which the case study stated. According to the page on strokes I (a 24 year-old in fit health) am not really at risk for a stroke. AEuSoes1 11:23, 5 September 2006 (UTC)

Some more information and links can be found under hallucinations and olfaction. There's also an unreferenced stub article on phantosmia. If you're worried, please go see a doctor. We cannot give medical advice at the reference desk. ---Sluzzelin 12:19, 5 September 2006 (UTC)

Is it possible you're actually around people who are smoking? Maybe they're smoking something close to cigarette smoke.--152.163.100.74 12:33, 5 September 2006 (UTC)

Intermittent smells can also be a sign of an impending seizure or migraine. See aura. Not common, but certainly possible. InvictaHOG 20:40, 5 September 2006 (UTC)

The whole "am I going to die" part was actually a joke. I've already been to a doctor about this and he thought it might be an allergy to something (if it walks like a duck...). Thanks for the info. AEuSoes1 21:02, 5 September 2006 (UTC)

Plane speed

If a plane is flying east to west, does it travel faster relative to the ground because of the spin of the earth? Or does the fact that the air it is in also spins cancel that out? Richard Bladen 13:24, 5 September 2006 (UTC)

The latter. Consider that at the equator the rotational speed of the Earth is over 1000 miles per hour, faster than the cruising speed of virtually all aircraft. However, US->Europe flights are usually of shorter duration than Europe->US flights due to prevalent winds. — Lomn | Talk 14:44, 5 September 2006 (UTC)

And for planes that get into the jet stream, the difference in speed is even more dramatic. Planes routinely use both ground speed and air speed to measure their velocity. StuRat 23:10, 5 September 2006 (UTC)

Thanks a lot Richard Bladen 00:25, 7 September 2006 (UTC)

Well, first I think you may have your directions mixed up. If you look down at the earth from above the North Pole, you'd see it spinning counter-clockwise. The sun rises in the east and sets in the west. Any "kick-start" you might expect from the earth's rotation would work in the opposite way. The Earth rotates "west to east", and so it would only add to velocity if you took off from the west heading east. Now the rest of you guys may think I'm being silly by talking about the Earth's rotation providing a "kick start". And in the case of planes which remain in the atmosphere you'd be right. The Earth spins, but so does its atmosphere along with it, so the whole "rotation of the Earth" factor wouldn't really have any relevance. However, when it comes to launching spacecraft into orbit, it's no coincidence that NASA chose Florida's Cape Canaveral, or that the French choose to launch their rockets from French Guyana in South America rather than from France. Two elements are at work here. The rotation of the Earth gets faster the closer one gets to the equator. That's why they chose Florida, the most southerly state in the continental US. Also, because the Earth spins "west to east", the best location would be somewhere on the east coast, so that God forbid anything should go wrong, the spacecraft would "splash-land" somewhere in the Atlantic Ocean off the Florida coast, rather than "crash-land" somewhere in Nevada if the launch site was in California. A "splash-land" is much safer for the crew, as the likelihood of their survival is much higher if they would "splash-land" in the sea rather than "crash-land" somewhere east of California. The prospect of debris (or in the case of the space shuttle, it's two booster rockets) falling into the ocean is also obviously much safer than having them land God knows where in some state east of California. And once the craft is up there, it tends maintain a "west to east" orbit of the Earth. Finally, when it is brought back to Earth, it also does so in a "west to east" fashion. Remember how they finally retired the old Russian Mir space station? The thing entered the atmosphere way off somewhere around Australia, and then burned up in the atmosphere over the South Pacific, minimizing the chances that anyone would get hurt by any possible falling debris. Also note the Columbia tragedy. It too was attempting a "west to east" landing in Florida. However as we all know something went wrong and the thing burned up in the atmosphere somewhere around Texas, leading to a great deal of debris landing in those states between Texas and Florida. Thankfully, (aside from the crew of course) I don't believe anyone was harmed on the ground. Sorry for going of on this huge tangent...I just thought it might be interesting for the questioner to know that s/he wasn't all wrong in making the instinctive assumption that the rotation of the Earth actually can be an extremely important factor, perhaps not with regard to air-flight, but definitely with regard to space-flight. Loomis 20:25, 10 September 2006 (UTC)

Keep your bowels fit?

Will your bowels deteriorate if they don't get anything to "work" with, food for instance? I was just wondering, if a person's nutritious requirements were met simply by eating a capsule the size of a walnut once a day (very futuristic), leaving the bowels inactive for most of the day, would the bowels stop working/deteriorate in function? Jack Daw 13:37, 5 September 2006 (UTC)

Your body would still need to dispose of bile and dead blood cells - the stuff that makes your poop green or brown (depending on which is in excess). So, even without food, your bowels would continue pushing "stuff" through. I think the real "victim" would be the population of bacteria in your bowels waiting for something good to eat. --Kainaw ^(talk) 13:55, 5 September 2006 (UTC)

So what about the bacteria then? What would happened to them, and how would that affect us? Jack Daw 14:27, 5 September 2006 (UTC)

The bacteria are part of your immune system. Without them, any foreign bacteria that make it to your gut will have an easier time causing disease. Of course, since you're not eating much, fewer foreign bacteria will make it to the gut in the first place. --Serie 22:41, 6 September 2006 (UTC)

I'm actually not sure anybody knows the answer to this, since such a diet does not yet exist. Some information may be gleaned from victims of malnutrition, but the malnutrition itself confounds the observation. In other words, it may not be clear whether a particular intestinal symptom is due to lack of activity in the bowel or to lack of nutrition for the cells. See below. --Ginkgo100 ^{talk · e@} 20:20, 5 September 2006 (UTC)

Actually, the bowel begins to decondition shortly after a person stops eating/drinking. This happens a lot in the ICU setting. As for bypassing the bowel entirely, we don't need pills. We actually routinely completely bypass the bowel by using total parenteral nutrition, which is basically food through the veins. There are people who have lived decades without eating. InvictaHOG 20:42, 5 September 2006 (UTC)

So, yes, the bowels will deteriorate without food, perhaps to the point where they become completely unusable, forcing the victim to live the rest of their life getting all their nutrition via an IV. Not a pleasant prospect. StuRat 23:05, 5 September 2006 (UTC)

I believe this is an issue for astronaut food - the bowels need something to work on, so just pill food won't do. Strangely I can't find anything on that in Wikipedia. DirkvdM 09:26, 6 September 2006 (UTC)

Oh, I should have thought of that. *smacks head* Of course there are ways to provide nutrition besides through the gut. --Ginkgo100 ^{talk · e@} 22:05, 6 September 2006 (UTC)

How does retinol kill?

The retinol article says that retinol can kill you, but How? It doesn't say. Anyone's got an answer?

The liver eventually can't store any more retinoids and they enter the blood stream causing a strong and dangerous immunological response called sepsis. See also hypervitaminosis A.---Sluzzelin 14:20, 5 September 2006 (UTC)

I see. And why does increased serum retinol cause sepsis? Jack Daw 14:26, 5 September 2006 (UTC)

On a similar subject, said article also states that: "The livers of certain animals, especially those adapted to polar environments, often contain amounts of vitamin A that would be toxic to humans." Why do polar animals have greater hepatic concentrations of retinol? I suppose it helps them in some way, but how? Jack Daw 13:42, 5 September 2006 (UTC)

Due to the scarcity of vegetable food, arctic super-predators, such as polar bears, eat a lot of other animals who are also predators. Organic compounds tend to accumulate up the food pyramid. See biomagnification. Higher hepatic concentration of retinol doesn't help the animals directly, some of them have just adapted greater storage capacity for organic compounds, thus avoiding sepsis. ---Sluzzelin 14:20, 5 September 2006 (UTC)

Naturally. Thank you. DS

request for location of manuals and papers

Can somebody say me a good website to find detailed and illustrated manuals and papers on any of the following topics : neural network, artificial intelligence, power electronics, power quality, robotics, VLSI, HVDC transmission and electronic topics? thank you for your help.

Start by searching for the terms in Wikipedia, and reading the articles you find. Then read the references in the Wikipedia articles. Then Google the terms and read the websites you find. Then go to a public library and ask the reference librarian to help you find books and magazines on the topics of greatest interest. Edison 20:19, 5 September 2006 (UTC)

Edison made some good points. --Proficient 04:05, 6 September 2006 (UTC)

backlog?

Has it ever occured to anyone how much Backlog sounds like B'log? Blog? Backlog? What are the scientific chances that 2 unrelated words would sound so similar--152.163.100.74 14:15, 5 September 2006 (UTC)

This is a rather vague question. Anyway, the words are related -- quite closely. They're two compound words both using "log" plus a leading descriptor. As for sounding alike... I find that it's fairly hard to confuse a two-syllable word with a one-syllable word, particularly when the extra syllable is the stressed one. However, languages generally reuse bits of sound (check the Language desk for better explanations). For example, a word starting with "str" is scientifically unlikely if you just generate character strings, but it's easy to think of a great many English words satisfying the condition. — Lomn | Talk 14:56, 5 September 2006 (UTC)

They're called homophones. JackofOz 00:09, 6 September 2006 (UTC)

I see where you're coming from, but I don't quite agree that they sound so similar. --Proficient 04:06, 6 September 2006 (UTC)

hahahah what ar ethe scientific chances?!?? omg I love the hubris and faith on this site. I...um...calculated it using computational linguistics. The chance is 1/15212. Jasbutal 04:42, 6 September 2006 (UTC)

I recall reading somewhere that there is a tendency for homonymy in languages. Probably has something to do with needing to remember less words with more definitions.

Gourami identification needed

Some type of gourami, sold to me as simply a "golden gourami"

I need help identifying which species is in this picture. I own the fish, but I never bothered to ask what species it is. The image is currently on Trichogaster trichopterus because it mentions "golden" varieties, but I'm not sure if that's right (the markings look different). Help would be greatly appreciated. --Pharaoh Hound (talk) 14:59, 5 September 2006 (UTC)

It is a golden variety of blue gourami (Trichogaster trichopterus) as you thought. --Ginkgo100 ^{talk · e@} 20:08, 5 September 2006 (UTC)

Thanks! (sorry I didn't answer sooner, the server was locked for maintenence when I tried yesterday) --Pharaoh Hound (talk) 12:43, 6 September 2006 (UTC)

Simple Law of Motion Question

Simply stated, in a practical application, would a ball dropped in a moving train fall directly down, or would it experience some movement towards the back of the train (assuming the train is moving at a constant speed)?

From the pov of someone in the same carriage, the ball would appear to drop vertically to th e floor. From the point of view of someone watching from the trackside, the ball would appear to travel in a parabolic trajectory.--Light current 15:16, 5 September 2006 (UTC)

[Edit conflict] (Assuming the train and ball are already travelling at a constant velocity) To a person on the train, the ball falls straight down. To a person obseving from outside the train, the ball falls both down (accelerating at one g) at forward (at the velocity of the train). Raul654 15:17, 5 September 2006 (UTC)

Should your train for any reason at all be situated in space, the ball, once dropped, should move alongside you without much trouble at all. :) 81.93.102.45 16:55, 5 September 2006 (UTC)

It is accelaration that would cause the ball to fall in a curved path relative to the train, not velocity, assuming the carridge is a sealed capsule, (i.e. if your on a flat bed, the wind would blow it back). Philc _T^E_C^I 20:10, 5 September 2006 (UTC)

There's always a caveat, so just to ruin the party: if the traincar in question has a lot of open windows, the resulting draft would push the ball towards the back of the train. Melchoir 20:17, 5 September 2006 (UTC)

Also, the ball would only fall straight down if the train is moving at constant speed in a straight direction. StuRat 22:50, 5 September 2006 (UTC)

If windows are open, the air current can go in many directions, depending on where you are located. Often, right next to a window, there may actually be a strong forward wind. (btw, is the similarity between 'wind' and 'window' purely coincidental?) DirkvdM 09:31, 6 September 2006 (UTC)

Wiktionary claims it isn't, it's actually derived from wind. And there's also "windscreen". – b_jonas 12:14, 6 September 2006 (UTC)

Ha! Another thing I make up that turns out to be true. It's a good thing I make up most of the things I say. That way there's a good chance I get it right. :) DirkvdM 17:54, 6 September 2006 (UTC)

Strange insect identification

Unknown insect

Hello, can anybody help me identify this strange insect I found in my garden? Thanks in advance. Davide125

Froghopper? It looks like the insects that come out of cuckoo spit in my garden, and cuckoo spit redirects to that page. Skittle 17:23, 5 September 2006 (UTC)

Froghoppers are rather small. How big is this critter? Also it might help to know which country your garden is in.--Shantavira 17:28, 5 September 2006 (UTC)

Me? England. I thought this beastie looked smallish too, given its size against the leaf. Happy to be corrected though. Skittle 17:30, 5 September 2006 (UTC)

Thank you for your reply. The insect is pretty small, about 3-3.5 cm including the antennas. The garden is in northern Italy. Davide125 18:21, 5 September 2006 (UTC)

It is some sort of bug - that's as specific as I can be, I'm afraid. You can tell it's a bug by its long ventrally retracted mouthparts, just visible in the photo. BenC7 10:08, 7 September 2006 (UTC)

Just from having a quick browse, it appears to be from one of the families of heteroptera. Maybe a type of leaf-footed bug. BenC7 10:15, 7 September 2006 (UTC)

Construction of Light Emiting Diodes (LEDs)

I am particularly working on a project whereby I need to construct a 2-Volts-DC LED lighting — 17:38, 5 September 2006 (UTC)17:38, 5 September 2006 (UTC)83.229.66.186

Construct from what starting point? Do you have a handful of LEDs and resistors from Radio Shack? Do you have a some PN junctions? Do you have some appropriately-doped pure semiconductors? An undoped Si crystal? A pail of beach sand? DMacks 19:03, 5 September 2006 (UTC)

Hehe, I have sometimes thought about how long it would take to, say, build a computer, if all you had to start with was the natural resources. One could imagine that mankind, because of a natural disaster or something, lost all of present technology. Mabye there is only some tenths or hundreds of people left. How many generations would it take to build a computer (or go to the moon, or build a submarine, …)? The first generation would have to try to pass on all their knowledge to the next (a great task in itself), but they hardly know everything, so future generations would have to, well, not reinvent the wheel, but a whole lot of other things. Or could it be accomplished while the starting generation is still alive? —Bromskloss 21:33, 5 September 2006 (UTC)

Make sure you download Wikipedia (how is that even possible) before the downfall of civilization. It would give quite a jumpstart. Imagine Michael Faraday or Joseph Henry with a laptop containing all Wkipedia articles, and the jumpstart it would give science and technology.(I chose their era so they could build batteries to power it). Edison 15:11, 6 September 2006 (UTC)

Yeah, but when they found out that (on the day of download) "My teacher says that Isaac Newton is soooo gay!", they might not want to work with him anymore. ;-)

Atlant 00:06, 7 September 2006 (UTC)

Given that you have the led and a 2 volt light source, the big trick is to connect the led so that it is biased to conduct electricity, and to have a resistance in the circuit to limit the current to an appropriate amount. See LED circuits. An LED connected across a battery without a limiting resistor would generally fry when forward biased. Edison 20:24, 5 September 2006 (UTC)

A lot of modern LED flashlights seem to skip the limiting resistor and just count on the battery's internal impedance to limit the current flow. Given the rather small difference between 2V supply and the forward voltage of the diode, the choice of resistor is pretty problematic anyway: the correct value of the resistor would be very sensitive to small variations in the battery voltage and the LED forward voltage. Many modern designs now get around this dilemma by using sophisticated active regulator ICs rather than mere passive resistors. The active regulator also wastes less power than a passive resistor and allows draining the battery further, optimizing its service life.

One reference: http://www.elecdesign.com/Articles/ArticleID/13284/13284.html

(But Google will find you many more)

Atlant 00:11, 7 September 2006 (UTC)

what kind of mirror has best reflection of visible light ?

I want to know how much percent the best mirror for the visible light,reflects ? —The preceding unsigned comment was added by J.hesam (talk • contribs) .

Maybe spectralon. Its reflectance exceeds 99%.---Sluzzelin 19:07, 5 September 2006 (UTC)

The "Technology" section of the Mirrors page has some info. DMacks 19:08, 5 September 2006 (UTC)

Dielectric mirrors can reflect >99.999% of a narrow band of wavelengths. In 1998, MIT claimed they had created a so-called perfect mirror that was a "very efficient reflector over a broad range of angles". I haven't been able to find any exact numbers or more recent details about it, though, so it might not be much more than a research prototype. -- Plutortalkcontribs 19:11, 5 September 2006 (UTC)

I found a few (potential) primary citations for that work...see Talk:Perfect mirror). DMacks 19:27, 5 September 2006 (UTC)

Sluzzelin: the spectralon article claims that it has a very high diffuse reflection, so it's definitely not a perfect mirror. – b_jonas 21:27, 5 September 2006 (UTC)

Dielectric mirrors, as mentioned. — [Mac Davis] (talk) (Desk|Help me improve)

See total internal reflection. Of course you have to be inside the high-refractive index medium. --Trovatore 04:54, 6 September 2006 (UTC)

...and you have to be away from perpendicular. List of indices of refraction suggests that 4 is a very large value for n and 1 is smallest. That interface would give a θ_c of about 14.5 °, meaning there's a ~29-degree cone of non-mirroring. DMacks 05:30, 6 September 2006 (UTC)

Is there such a thing as an active (powered) mirror that amplifies the incoming light, thus exceeding 100% reflection? DirkvdM 09:35, 6 September 2006 (UTC)

I don't know, but there are shaving mirrors with fluorescent lamps in their frame that illuminates your face. – b_jonas 12:02, 6 September 2006 (UTC)

Lasers do this (monochromatically). Linear cavity lasers do this by design. (Ring lasers, ..., not so much.) There are patents for 3-color image intensifier goggles, but I don't see how one could do this in the form factor of a mirror. -- Fuzzyeric 06:57, 7 September 2006 (UTC)

What would happen

if an unstoppable force collided with an immovable object (assuming it were possible)? A Clown in the Dark 18:22, 5 September 2006 (UTC)

Irresistible force paradox ---Sluzzelin 18:51, 5 September 2006 (UTC)

Ah, that was simple. Thanks! A Clown in the Dark 18:52, 5 September 2006 (UTC)

I think this is Lambiam's principle of explosion. :) Rentwa 21:11, 5 September 2006 (UTC)

I love that paradox. --Proficient 04:07, 6 September 2006 (UTC)

Makes me wonder. Is it possible to ask a question that hasn't been asked before? How many people will already have asked that question? (And how many people will already have asked that (and how many ... ok, let's rule out recursion)). DirkvdM 09:37, 6 September 2006 (UTC)

Maybe there should be a continuously updated index of all the questions that have ever been asked on the Ref Desk. Of course, that would require them having meaningful titles, not just things like "Question", or "What would happen". You seem to have a bit of spare time on your hands, Dirk, so why don't you get the indexing project started. Call me if you have any questions.  :--) JackofOz 10:19, 6 September 2006 (UTC)

What, with all the time I spend on the ref desk, what makes you think I've got spare time on my hands? Or was that your point? Well, it's mine too. (reminds me of the question of whether the presence of a lot of police in a neighbourhood means it's very safe or very unsafe) DirkvdM 18:00, 6 September 2006 (UTC)

Well, you tell us you haven't worked in 15 years, and you seem to go travelling around the world at the drop of a hat. Actually, you seem not only to have a lot of spare time on your hands, but a lot of spare cash as well, despite no job for a very long time. How do you do it? What is your secret? JackofOz 21:12, 10 September 2006 (UTC)

faqs.org has a quite good index of FAQs in various topics. – b_jonas 11:56, 6 September 2006 (UTC)

The unstoppable force would simply change direction - it would 'bounce off the immovable object.

In a sense this happens every day, when two objects are in compression against each other - one is an unstoppable force, the other is unmovable.

Errr...it would not change direction. For the unstoppable force to change direction, it would have to stop.

It would not have to stop if it changed direction instanateously. If for example, you fired a bullet at a heavy steel plate it would not stop but ricochet.

genetically modified foods

what is the mean of genetically modified foods?

Basically it is transformation with new DNA, often from an unrelated organism. David D. (Talk) 21:11, 5 September 2006 (UTC)

Perhaps typing "genetically modified foods" into the Search box would have been a good place to start learning on your own... DMacks 21:13, 5 September 2006 (UTC)

Do you mean what the average genetically modified food is or what the meaning is or why they are mean? Or am I being mean now? (And don't tell me I'm average, or I'll get really mean.) DirkvdM 09:41, 6 September 2006 (UTC)

What is the process of liqiudizing Oxygen?

I just want to ask a question about liquidizing Oxygen. Thank you. --64.180.82.114 21:40, 5 September 2006 (UTC)

According to Liquid oxygen, the usual process is fractional distillation. I guess you just condense ordinary air first. Melchoir 21:42, 5 September 2006 (UTC)

You would also need to lower the temp quite a bit, wouldn't you ? StuRat 22:51, 5 September 2006 (UTC)

Liquid air talks about how to condense ordinary air, including separation of different components by their boiling point. DMacks 23:01, 5 September 2006 (UTC)

Ah, there's the money link. I've put it into the See also. Melchoir 23:20, 5 September 2006 (UTC)

On a lab scale (do not try this at home!) passing a flow of oxygen gas thorough a liquid nitrogen cooled copper coil gives access to tens of mLs of liquid oxygen terrifyingly quickly. for great fun for those slow fridays, i recommend cotton wool. Xcomradex 02:28, 6 September 2006 (UTC)

How about the Linde process for the liquefaction of air?--Light current 18:05, 6 September 2006 (UTC)

Information on the Linde process is currently scattered among Carl von Linde, Liquid air (already mentioned), and Joule-Thomson effect. I'm not sure where the redirect for Linde process should point. Or maybe it should be unified into its own actual page? DMacks 18:12, 6 September 2006 (UTC)

It must be (or have been) an important process: I remember covering it at school! Redirect should point to liquid air--Light current 18:47, 6 September 2006 (UTC)

PV=nRT. Just like air in a can gets cold from the change on volume and pressure sucks out the energy from the surroundings, you would start by making dry ice using compressed Co2 cooling the system down then switch to compressed O2 but it is very very very dangerous!!!! Is you need a heat dump use liquid N2

Reference voltage for decibel measurement

When calculating frequency repsonse on electronic hifi equipment, what is the reference voltage for the decibel measuremnet used in a frequency vs dB graph? Is it the ' perfect ' output voltage?

I think its 0 dBm ie 775 mV rms (in a 600R system).--Light current 23:58, 5 September 2006 (UTC)

Many experimenters fail to control impedance in calculating/measuring decibels. And did you mean 600 ohms? Did dBm mean "decibel referenced to a milliwatt across 600 ohms? Edison 15:39, 6 September 2006 (UTC)

Yes in 600 ohms (R is the unit for ohms) Try this calc [9] --Light current 17:57, 6 September 2006 (UTC)

The graph shows gain, which is output power divided by input power. The reference is therefore the input. There is no need for an arbitrary reference level. See this random example I found on Google. The y axis is marked 'Gain', as it should be. --Heron 22:00, 6 September 2006 (UTC)

Remember, all decibels are just a ratio between two values. So when an amplifier states (for example), that it has a frequency response of 20Hz to 20KHz ± 0.1 dB, what that means is that if you plotted the frequency response from 20 Hz to 20 KHz, the line that represents the frequency response would stay within a band that is 0.2 dB high. In this case, the ratio you're measuring is the ratio between the best gain of the amplifier (within our specified frequency band) and the worst gain of the amplifier (within our band).

Any time you see dB representing an absolute value, there'll always be some indication of what the value is ratio'd from. For example, the dBm that folks were speaking of above is a ratio from 1 milliwatt. If someone says dBV, then they're expressing a ratio from 1 volt. dbA is a ratio of acoustic power related to a particular absolute value of sound pressure level (the softest sound the average person can hear at 2KHz) and weghted according to an "A" frequency response curve (a particular weighting curve that has something to do with the response of human hearing).

Atlant 01:05, 7 September 2006 (UTC)

canine dental

I have a five month old Standard Poodle, that has adult teeth coming in missing enamel on 1/3 to 1/2 of each tooth. I am researching the probability of heredity/genetic traits to notify the breeder of possible health related concerns. All her teeth will have to be capped to prevent decay. I have read many articles suggesting auto-immune issues; and want more information on related documented cases and results. I can send pictures. Thank you. <Do you want Viagra for only $10?>

I'm only familiar with enamel hypoplasia in dogs as related to canine distemper, but according to the Merck Veterinary Manual, it can also be caused by malnutrition and possibly inherited [10]. --Joelmills 01:46, 6 September 2006 (UTC)

Yes, thank you. Dr. Bellows, dentalvet, has the same opinion.

My journey: (1) is to find out if this is related to the 3- series puppy-shot that contain "parvo, influenza, distemper & hep." when administered with an undetected low-grade fever, (2) or, if there is a heredity-gene trait and is there a genetic test available? (3) to answer a question swarming my brain; what could destroy the mineral presentation of "Hydroxyapatite" during the "Odontoblast period" of the "Dentinogenesis" formation?

I am no scientist or practioner....just want answers to why my puppy has permanent damage to all her adult teeth, like a line was drawn and half of each tooth has no enamel. It is suggested that the "leukocyte alkaline phosphatasa" found in white blood cells, could lead my way to more knowlegde. I will have her tested for amenia and hypothyroidism. Perhaps the vaccines, eliminated the part of her immune-system that protects the "Dentinogenesis" formation.

September 6

Ejaculation

Is there any way of shortening the "refill time" after I've ejaculated semen from my penis? Do any of those pills you see advertised on the internet that claim they do this really work?

The "refilling time" you refer to is called a refractory period Raul654 00:30, 6 September 2006 (UTC)

Also, from that article, The refractory period varies widely between individuals, ranging from minutes to hours. An increased infusion of the hormone oxytocin during ejaculation is believed to be chiefly responsible for the refractory period and the amount by which oxytocin is increased may affect the length of each refractory period. Another chemical which is considered to be responsible for this effect is prolactin, which represses dopamine, which is responsible for sexual arousal. So I suppose any enzyme that breaks down either prolactin or oxytocin could theoretically decrease the time of a sexual refractory period. Raul654 00:32, 6 September 2006 (UTC)

Perhaps training yourself to need less time will work. --Proficient 04:12, 6 September 2006 (UTC)

What sort of training did you have in mind?--Light current 18:00, 6 September 2006 (UTC)

I consider myself an expert in the field and would definetely recommend "milking" which would induce your body to keep up with the demand. - Tutmosis 01:26, 7 September 2006 (UTC)

Can you eleaborate?--Light current 14:31, 7 September 2006 (UTC)

Its very simple, milking is forced (A.K.A planned & executed) masturbation a number of times a day to force your body to increase sperm production as well as the rate. Years of training will give you results so great that you will even forget what being "dry" means. - Tutmosis 00:36, 8 September 2006 (UTC)

OK thats assuming you can do it more than once a day. You must be a youngster! Enjoy it whilst you can! 8-)--Light current 00:38, 8 September 2006 (UTC)

I have to admit I dont have the swing I used to have but I'm sure with hard work and devotion we can all "spray the goodness" again. - Tutmosis 00:48, 8 September 2006 (UTC)

o_o --Froth 20:27, 8 September 2006 (UTC)

TMI Raul654 20:35, 8 September 2006 (UTC)

AS long as youre not doing it whilst editing, I can deal with that! 8-)--Light current 00:50, 8 September 2006 (UTC)

Mouthwash, alcohol, toxicity, &c.

I hold in my hand a travel bottle of Scope® mouthwash, a generous, easily-confiscatable gift from the good people at Continental Airlines. In the air, I wondered out loud whether one could obtain more alcohol from the bottle of Scope than from the little bottles of wine they were giving out. I also secretly suspected the Scope would be less sweet. I was thinking of the old comedy trope of the high school kid getting wasted on Listerine or the Vietnam veteran hooked on cough syrup. But, as I discovered a minute later, the label advises any unlucky ingester to contact a poison control center immediately. This Scope contains 15% alcohol by volume, as well as water, glycerin, "flavor", polysorbate 80, sodium saccharin, sodium benzoate, cetylpyridinium chloride, benzoic acid, blue 1, and yellow 5. Presumably cetylpyridinium chloride is the toxin, but in what concentration does it pose a threat to the human body? I remember, as young children, my brother and I unwittingly drank brimming Dixie cups of the stuff, not realizing the idea was to spit it out. Nor can I recall suffering any ill effects. I ask someone with a knowledge of chemistry: Is the Listerine lush an inaccurate or outdated trope (perhaps due to an advance in mouthwash technology), or alternatively, has the toxicity of mouthwash been exaggerated, perhaps to prevent lawsuits and substance abuse? Bhumiya (said/done) 04:59, 6 September 2006 (UTC)

Here's what Straight Dope says: [11] -- Scientizzle 05:19, 6 September 2006 (UTC)

Interesting. Thanks for the quick response. Bhumiya (said/done) 05:30, 6 September 2006 (UTC)

And wow, who would ever think of replacing mouth wash with pure vodka with a little food coloring???

I'm surprised that nobody has mentioned that there are two kinds of alcohol, and that the industrial cheaper kind is POISONOUS and will send you blind. I have often heard on the BBC news of people in India and elsewhere who drank cheap alcohol without being aware it was the industrial kind and went blind. The industrial kind is also that found in chemistry labs. It may also be the alcohol in mouth washes - so I wouldnt drink it. The two types of alcohol do have different names but I cannot reliably tell you what they are. 81.104.12.107 20:19, 10 September 2006 (UTC)

Genetic Gender

Why do some couples have say three girls, whilst other have three boys? Is this just the luck of the draw, or is there something else going on, like a genetic leaning toward having children of a certain sex?

See Sex ratio, Sex-determination system and XY sex-determination system for the genetics behind it. It's essentially the luck of the draw, as I understand it. --Robert Merkel 09:14, 6 September 2006 (UTC)

Statistics is one of the least understood things (alas, because a good understanding of it is essential to understanding the world around you). Having 10 children of the same gender sounds so unlikely that the couple that had them would probably think there was something special going on. But the chances are 1 in 512, which makes it likely that once in a while it will happen (if there are enough cuples that have 10 kids, that is). But then people will think that the fact that it happened to them specifically is significant. It isn't. No-one would think anything of having 3 boys and 7 girls in a specific order, but he chances are exactly the same. DirkvdM 09:52, 6 September 2006 (UTC)

"The chances are exactly the same" — that's true, but when most people say that MMMMMM looks more un-random than MFFMFM, they usually mean something more akin to "the odds of getting a non-homegenous pattern are much higher than getting a homogenous one", which is true. Unfortunately I doubt most people know that's what they're actually referring to when they say the first sequence looks more significant than the latter. It's the same thing as when statisticians deride people for choosing 010010 as the "more random" sequence than 000000; if each element is independently determined, then any single outcome is as likely as another, but if one is instead taking a more intuitive, "homogenous/nonhomogenous" approach then indeed, you'd expect more truly randomly generated sequences to "look like" the first one than the second. --Fastfission 18:14, 6 September 2006 (UTC)

I remember hearing that certain conditions could lead to men having more girls than boys. I think it was high levels of testosterone, which can also lead to early baldness. I don't have a source for this though, but I'm sure Karl Kruszelnicki mentioned the link once. If anyone has better info it'd be appreciated. I should probably check the articles mentioned too. —Pengo ^{talk · contribs} 11:47, 6 September 2006 (UTC)

The sex ratio article links to a couple articles about research that indicate that men infected with Hepatitis B have more male children. There was also some recent press about a study that showed that attractive people were more likely to have female children and some articles mentioned previous studies by Satoshi Kanazawa that showed that scientists, mathematicians engineers, big or tall parents and violent fathers are all more likely to have sons than daughters. It seems pretty certain to me that all couples do not have the exact same 50-50 chance of boy and girl children. -- Plutortalkcontribs 13:02, 6 September 2006 (UTC)

It's not a 50-50 chance, even on the average. More boys are born than girls. --Trovatore 21:10, 6 September 2006 (UTC)

Note however, that the the ratio of sexes born need not be the same as the ratio of sexes conceived. The sex of a foetus will be determined at conception, however, during the 9 months in utero, there could well be differences in survival rates between sexes. There could also be genetic predispositions to bearing children of one sex over the other, theoretically at least. For example, consider a mother who has an allele on one of the X-chromosomes that, when hemizygous would cause early embryonic lethality by haploinsufficiency (lets ignore the problems that Lyonisation would cause her or her female children, for the moment). All else being equal, every child born to her would have a 1/3 probability of being male, rather than a 1/2. However, the probability of her conceiving a child of either sex remains 1/2, respectively. I am not familiar with an exact gene that this model would fit this example, but i'll wager it happens. Thus having multiple children of the same sex is most often simply due to chance, but i would argue that a specific genetic predispositions cannot be ruled out. Rockpocket 01:12, 7 September 2006 (UTC)

I think you're wrong about the probability of conception for either sex being 1/2. If I recall correctly, male fetuses are more likely to die before birth, so the disparity at time of conception must be even larger than the disparity at time of birth. Of course, that could be rolled into your "other things being equal", but my point is that other things are not equal. --Trovatore 03:50, 7 September 2006 (UTC)

Possibly true. However, the problem with the data you mention, is that it is based on later-pregnancy miscarriages. As much as 50% of all conceptions fail: its thought that around 1/4 of fertilized eggs fail to implant in the uterine wall and 1/3 are spontaneously aborted within the first six weeks after conception, both without the mother ever knowing she is pregnant. Since we have no idea of the sex ratio of these failures, the impact of the (relatively speaking) small number of later-stage male-biased miscarriages could be negligible. If these early failures balanced up the sex bias, your logic would fail. My assumption of equality was to demonstrate my theoretical point on the difference between conception/birth ratios in a simplified model. The fact is, we simply don't know if "other things are equal", as we don't have a full data set. Rockpocket 05:40, 7 September 2006 (UTC)

I think that's a stretch, frankly. The ratio of Y-carrying androsperm to X-carrying gynosperm is known, and the ratios of later fetuses is known, and both (unless I'm misinformed) support the idea that there are more male conceptions. I think you're overapplying the notoriously shaky principle of indifference. --Trovatore 07:33, 7 September 2006 (UTC)

I completely agree. Per Occam's razor, that certainly is the post parsimonious explanation. However, the possibility remains, however remote... Rockpocket 18:20, 7 September 2006 (UTC)

Sleep

Why do I get a headache if I'm fortunate enough to get too much sleep? And is this a common reaction to sleeping too much? Dismas|^(talk) 10:32, 6 September 2006 (UTC)

It's a known phenomenon. This article discusses a possible mechanism. --Lambiam^Talk 10:49, 6 September 2006 (UTC)

How much is too much, because I can't say I've ever had a headache from this. --liquidGhoul 11:00, 6 September 2006 (UTC)

I find it usually happens when I go to sleep again, i.e. when I half-wake up, decide that I don't want to get up at this time today, and wake up again a few hours later with a headache.  freshofftheufoΓΛĿЌ  14:03, 7 September 2006 (UTC)

Actually that article doesn't say much. It can be many things, including but not limited to:

1. Musculoskeletal discomfort due to prolonged immobility, imperfect bedding, or uncomfortable position;
2. Overheating;
3. Mild dehydration;
4. Low blood sugar;
5. Caffeine withdrawal;
6. Low blood pressure;
7. Poor sinus drainage (exacerbated by being prone);
8. Sleep apnea. Oxygen deprivation causes headaches, and the longer you're experiencing it, the worse a headache you'll get.

--Anchoress 11:09, 6 September 2006 (UTC)

Sn1&Sn2 Reactions

please tell me about following things in sn1 & sn2 reactions

1.Nature of substract
2.Nature of attacking nueclophile
3.Nature of leaving ion
4.Nature of solvent

It would probably be best if you look at SN1 reaction and SN2 reaction then come back with any specific questions you still have.--Ed (Edgar181) 13:59, 6 September 2006 (UTC)

A car for $1

What would you do if you see an ad like this:

• Offer for sale of EXACTLY ONE $30,000 car for $1.
• First come first served.
• However, you're required to throw a die:
  • If the 1st one in line gets a "1"; he/she takes the car home.
  • If the 2nd one in line gets a "1" or "2"; he/she takes the car home.
  • If the 3rd one in line gets a "1", "2" or "3"; he/she takes the car home. ...
  • Whatever 6th one in line gets; he/she takes the car home if all previous five did not make it.

If you want that car, what is your strategy to maximize your likelihood of winning? -- Toytoy 13:59, 6 September 2006 (UTC)

Just work out the probabilities. The first guy has a 1/6 chance of winning a roll, and a guaranteed chance to roll. The next has a 2/6 chance of winning if he rolls, but only a 5/6 chance of getting to roll. The calculations proceed thusly. — Lomn | Talk 14:17, 6 September 2006 (UTC)

I should note: a more interesting question is "what is a fair price for the chance to win the car?" Obviously the seller can't recoup his $30000 with $1 tickets, but if the tickets are only bought when the die is rolled (rather than in advance), what should he charge to average $30000 worth of tickets sold? — Lomn | Talk 14:21, 6 September 2006 (UTC)

Require 100 sided dice, then be last in line.

Hire some gorillas to prevent anyone else from queueing. So long as the hired help costs less than $29,994, you'll walk away smiling. --Dweller 14:28, 6 September 2006 (UTC)

Go 2nd or 3rd, it doesn't matter which.

Person I	Chance of rolling I	Chance of winning roll I	Odds of getting car I
1	1.00	0.17	0.17
2	0.83	0.33	0.28
3	0.56	0.50	0.28
4	0.28	0.67	0.19
5	0.09	0.83	0.08
6	0.02	1.00	0.02

- Nunh-huh 20:26, 6 September 2006 (UTC)

It might be an intersting game theory problem if you had a group of 6 people who each had to volunteer to go first, second, third etc. You'd have to set up the mechanism for volunteering in some specific way, but it might be interesting. --best, kevin [kzollman][talk] 21:43, 6 September 2006 (UTC)

If I saw this ad, and was able to determine it was not a marketing promotion, I would ignore it as a probable scam of some type, simply because common sense says that reasonable people don't just give away expensive cars. --Ginkgo100 ^{talk · e@} 21:50, 6 September 2006 (UTC)

Yea, like you may only be able to get the car for $1 if you agree to pay $40,000 for the car keys. :-) StuRat 23:35, 6 September 2006 (UTC)

If the car is legally yours, I'm pretty sure you could get new keys made (or the locks replaced) for less than $40,000. (In fact, you could probably get new keys to a car for less than $40,000 even if it wasn't legally yours, but that could cause other kinds of problems further down the line...) —Ilmari Karonen (talk) 01:26, 7 September 2006 (UTC)

I'm saying that the car wouldn't be legally yours (they wouldn't sign over the title) until you bought the $40,000 key, hence the trick. StuRat 06:36, 7 September 2006 (UTC)

I actually saw an ad once for a hideously expensive bicycle, that cost like a car, and you got a car with it. :-) —Bromskloss 13:54, 7 September 2006 (UTC)

BTW, this question should have been posted to the Math Ref Desk. StuRat 23:37, 6 September 2006 (UTC)

I'd buy all six tickets for $1 each, that's still just $6 for a $30000 car. – b_jonas 08:53, 7 September 2006 (UTC)

That answer sounds strangely familiar. --Dweller 09:40, 7 September 2006 (UTC)

yDNA Mutation Rates

What are the relative Mutation Rates of yDNA STR's used in Genetic Genealogy?......... Cymri

there are no good reliable published figures for those differential rates. The closest you'll get is a statement that a given STR is a "slow" (or "fast") mutater. - Nunh-huh 20:02, 6 September 2006 (UTC)

Ok Can anyone list the "fast" and "slow" Loci? or perhaps provide a limk to such information. cymri

Recognize this optimization problem?

I need to find a search algorithm for the following optimization problem. We are given $N$ (smallish) finite sets $A_{k}$, and we are to choose one element from each, to yield a multiset $B$ of size $N$. We are also given a finite mapping $\omega$ from multisets to real-valued weights, and we are to maximize the sum of the weights associated with the submultisets of $B$, $\sum _{C\subseteq B}\omega _{C}$.

If we constrain the domain of $\omega$ to multisets of size $1$, we can choose from each $A_{k}$ independently, and the problem is trivial.

If necessary, I can afford to constrain the domain of $\omega$ to multisets of size $2$, but I'm beginning to suspect that this is already NP-complete.

If it is NP-complete then I would appreciate any advice on approximations or reductions to other problems for which good solvers are available. Can I do better than the obvious reductions to ILP or weighted MAX-SAT?

Thanks and best wishes 128.220.220.95 19:20, 6 September 2006 (UTC)

I suggest you move this to the Mathematics reference desk. --Lambiam^Talk 23:02, 6 September 2006 (UTC)

Good point. I will start there next time. 128.220.220.95 17:00, 8 September 2006 (UTC)

If we allow $\omega _{C}\not =0\;\forall \left|C\right|\leq 3$, this problem would solve boolean satisfiability (in particular 3SAT), as you hinted with MAX-SAT. Consider $A_{k}=\{(k,0),(k,1)\}$; then, for each value $(k,i)$ in a disjunction (that is, $(k,0)$ if $\lnot x_{k}$ appears, and $(k,1)$ if $x_{k}$ appears), increment $\omega _{\{(k,i)\}}$. Then undo the double counting (where $(\lnot )x_{k}$ and $(\lnot )x_{k'}$ succeed in a term containing both anyway) by decrementing $\omega _{\{(k,i),(k',i')\}}$ for each pair of literals that appear in the same disjunction. Then repair three successes minus three handshakes by incrementing $\omega _{\{(k,i),(k',i'),(k'',i'')\}}$. Then maximize, and see if the result has value equal to the number of disjunctions (this can be done in polynomial time because there are no more than ${N \choose 1}+{N \choose 2}+{N \choose 3}\in O(N^{3})$ non-zero values of $\omega _{C}$). This reduction typically involves negative weights, which you might not have had in mind, but I imagine that it could be recast without them. Obviously the corresponding argument with $\left|C\right|\leq 2$ fails because it's 2SAT then, so I'm afraid I don't have any truly useful answer at the moment. Hope this helps. --Tardis 23:20, 6 September 2006 (UTC)

Very cool, and I believe I've just learned something from the 2-satisfiability article that allows me to finish your argument: 2-SAT can be done in polynomial time, but MAX-2-SAT is NP-complete. It looks like I'm back to the drawing board, so thanks for helping me figure that out sooner rather than later. 128.220.220.95 17:00, 8 September 2006 (UTC)

Dogs and people

I know that any answer to this question must remain as speculation: What do dogs think humans are? They must not think of us as fellow dogs, because we probably smell different, and they do not try to mate with us. Are they usually submissive because we appear to be much larger members of some other species? Does Wikipedia have any articles on this subject? Pete

There is a lot of debate over exactly how dog/human relations are or ought to be (i.e. does the human master represent the alpha pack member?), but I think one can say somewhat safely that most animals are not able to get into the sorts of relationships that dogs have with humans (even cats seem to have difficulty tolerating humans a lot of the time, much less non-pet animals), and it is precisely this character trait which has made dogs "man's best friend" as they say. For whatever reason they seem to be able to adapt to co-habilitation with humans very well, and many dogs seem to exhibit symptoms of real affection for their human owners (one can always wonder if it is a trick, but I'm pretty sure my dog likes me—she goes way above and beyond what would be necessary to get food and attention). Of course dog behavior towards humans can vary a lot with breed—some breeds are notoriously independent and stubborn, some are very easy to train, some are known to be very friendly towards people, and some are known for their ability to be quite violent to humans. Unfortunately we don't seem to have a lot on this (our Behavior subsection of the "Dog" article is really, really short). We have a short article on Companion dogs but it doesn't have much on dog psychology. --Fastfission 20:31, 6 September 2006 (UTC)

I'm not sure its proper to attribute the sort of cognitive abilities to dogs that allow them to classify us. Perhaps dogs don't classify animals in their environments in the same way humans do. It might not "occur" to a dog to ever think about what we are. I don't know much about research into animal cognition, but I'm not sure if there is any reason to think they classify their environment into species. --best, kevin [kzollman][talk] 21:40, 6 September 2006 (UTC)

Just a couple of things to add. Many dogs actually do try to "mate" with us, or at least our legs. As for being submissive to larger creatures, it may be counterintuitive but the truth is that the larger the dog, the more gentle and submissive it is. It tends to be those tiny rat-dogs, the Chihuahuas, the Toy Poodles etc. that tend to be the nastiest and the most anti-social towards many humans. Have you ever been growled or been given dirty looks by a giant St. Bernard or Golden Retriever? Loomis 21:47, 6 September 2006 (UTC)

I took care of a toy poodle (absolutely tiny) for a neighbor for a few days. He didn't seem to like me much, especially if he was on the ground and I was upright. He also tried to kill the vaccuum. However he was very mellow around most members of the household, he was usually very happy to just sit with/on you. Perhaps he was unusually well-trained, but he adapted very quickly to the change. 206.124.138.153 05:42, 9 September 2006 (UTC)

Based on my (limited) observations of dogs, individual dogs behave in a somewhat consistently different way with respect to members of different species: they don't greet cats like they greet dogs, and a dog that chases one unknown cat tends to chase them all. Yet the same dog will not chase humans, only bark at them. To the extent that it is reasonable to apply human labelling to what dogs "think", my best guess is that dogs think that dogs are dogs, cats are cats, and humans are humans. --Lambiam^Talk 23:12, 6 September 2006 (UTC)

We do have two relevant articles -- Animal cognition and Dog intelligence. --Halcatalyst 23:21, 6 September 2006 (UTC)

I go with dogs viewing their owner as the pack leader/alpha dog, whereas cats view their owner as their mother (even male owners). StuRat 23:20, 6 September 2006 (UTC)

This article from the NYT has something about the problems created by framing the interaction with your dog in the alpha dog theory. Dogs are not wolves, but also for a pack of wolves the social structure is not like that of a troop of chimps. --Lambiam^Talk 04:09, 7 September 2006 (UTC)

I believe that dogs and wolves are, in fact, one species. This means they can mate and produce fertile offspring. StuRat 02:05, 9 September 2006 (UTC)

Supporting that thought... the best way to completely immobilize a cat is to pick it up by the scruff of its neck, like the mother cat does. --Halcatalyst 23:23, 6 September 2006 (UTC)

The immobilization reflex is mechanical and has nothing to do with how the cat views us. --Lambiam^Talk 04:09, 7 September 2006 (UTC)

Behaviourists from John B. Watson to B.F. Skinner saw no need to postulate what animals or people thought. Instead they saw our actions as the result of behavioural conditioning. The question of what a dog thinks a person is would be as meaningless as the question of what a person thinks a dog is (toy? child substitute?). They might note behaviours such as a cat kneading the owner stomach as learned from the utility of that conditioned response in obtaining milk from the mother. Cognitive psychologists theorize about internal mental states and how they control behaviour.

Many dog owners would say that dogs seem to think they and people are not that different, whether it be two kinds of dog or two kinds of people. Edison 23:40, 6 September 2006 (UTC)

Hmm. Sounds like a classical case of psychological projection to me. --Lambiam^Talk 04:13, 7 September 2006 (UTC)

I thought if the dogs were bigger, the more agressive and less social they were. ._. --Proficient 04:18, 7 September 2006 (UTC)

St. Bernards are quite large, but they're highly social as well as gentle. Behavioural traits aren't necessarily tied to the size at all; I've seen small dogs that are insanely aggressive. -- Consumed Crustacean (talk) 04:25, 7 September 2006 (UTC)

I believe the counterintuitive result that small dogs are more aggressive is due to artificial selection. While an aggressive small dog is considered by some to be acceptable, or even cute, an aggressive large dog is seen as dangerous. Thus, aggressive large dogs were less wanted and less likely to be bred than aggressive small dogs. After a few thousand generations, this leads to a lack of aggressive, large dog breeds. StuRat 04:29, 7 September 2006 (UTC)

That is entirely possible. Behaviour doesn't occur in a vacuum, however, and another factor is fear. Most animals will display aggressive behaviour when they feel threatened or harrassed - the fight part of fight or flight. The size of a dog in relation to the threatening cue is a factor in where they feel threatened or not, hence small dogs may be more likely to be aggressive than large ones, simply because they are more afraid. Genetics play a role in this too, of course. Note that we have bred larger dogs to be working dogs. Having them afraid of, or aggressive with, humans is not an ideal characteristic for their function. So that has been selected against. On the other hand, small show dogs are bred for how they look, so their fear of humans (as StuRat suggests) is inconsequential for their function. Rockpocket 06:00, 7 September 2006 (UTC)

William Gray (Meteorologist)

I have searched all over the internet for some background information on William Gray the hurricane forecastor and am unable to find out his birth date, where he was born and general information on his childhood. I did find ample information on the work he has done in hurricane forecasting but would be very gratefull if someone could help me on his background.

regards,

mactennis.

A recent article[12] says he's 76. That narrows his birth down, so you can try more searches to pinpoint it. Melchoir 21:06, 6 September 2006 (UTC)

Trying to get glasses

Three years ago I failed my school's eye exam and since then I have been to the eye doctor three times. Each time, the doctor told me that I was really close to needing glasses but my perscription is so small it would not even be worth it. Is there anything I can do to tip the scales in favor of requiring glasses within the year? Advice would be appreciated.

Usually I respond to people who are honest. Just say - "it may be a small correction, but it really means a lot to me. Could you please prescribe me glasses so I can use them when I feel I need to?" If they will not sell you glasses, ask for your refractive error. If all else fails, see a different doctor! InvictaHOG 01:28, 7 September 2006 (UTC)

Watch television up close, read in the dark, and neglect your carrot consumption. Staring at wikipedia pages all day will probably help too. AEuSoes1 02:20, 7 September 2006 (UTC)

I think I once read that reading in the dark doesn't hurt your eyesight, but that might have been a myth. --Proficient 04:20, 7 September 2006 (UTC)

Yeah, I don't see how it would. Carrots also don't help with eyesight. I was being facetiously misleading. AEuSoes1 05:31, 7 September 2006 (UTC)

How often do you masturbate, any room for improvement? Some people continue to believe that "self abuse" leads to deterioration of eyesight. That is almost universally dismissed by doctors as untrue, of course, but what have you got to lose ;)? In all seriousness, it is inadvisable to try any technique to make your eyesight worse. Anything the might work would also run the risk of damaging your eyes. Your optometrist is most likely delaying the inevitable out of a misplaced concern that you might not wish to have specs. as InvictaHOG suggested, I would recommend explaining honestly and firmly that you would like to have your vision corrected and would appreciate if they could do that for you. If they can't, take your future business elsewhere. Rockpocket 06:44, 7 September 2006 (UTC)

You obviously think you need glasses, but why? If you are having difficulty in reading small print, pick up some cheap reading glasses at a drug store/chemist.--Shantavira 07:16, 7 September 2006 (UTC)

• The doctor said the prescription was too small to require correction. Have you ever asked him what the values where. If it was anything up to 0.5 of correction, he is probably correct about you not needing correction. By the way, the fact you go to the eye doctor once a year (or at least three times in three years) is something you should continue. Having your eyes checked should be something as regular as having your teeth checked. - Mgm|^(talk) 07:28, 7 September 2006 (UTC)

I was like this, aged about 10. I thought that wearing glasses would improve my appearance(!) (Sigh) I even pretended in sight examinations that I couldn't read very small letters on the sight chart that I actually could read. I was therefore prescribed glasses of the wrong prescription, before I needed them. I've been wearing glasses ever since and now can't cope without them. The deterioration of my sight is probably mostly down to nature, but in an ignorant lay manner, my gut instinct is to attribute some of the blame to this stupid behaviour. So, my advice (as an ignorant lay person)?

• 1. Don't contemplate pretending your sight is worse than it is
  2. Avoid wearing prescription lenses for as long as you can, within the sensible advice of your optometrist
  3. Don't pick up "cheap reading glasses" that haven't been prescribed for you if you're young enough that "three years ago" you were still at school
  4. Glasses don't make you look clever or glamorous or alluring or mysterious. If you're tempted, think Clark Kent v Superman.
  5. Don't do stupid things that you'll regret later in life.heck, that's what being young is all about, isn't it? Anyway, I ain't young and I do really stupid things all the time--Dweller 10:00, 7 September 2006 (UTC)

Or just buy glasses that have no refraction index?  freshofftheufoΓΛĿЌ  13:52, 7 September 2006 (UTC)

Im puzzled that the school eye exam says you need glasses when a professional optometrist says you dont. I know whom I would believe (the pro)--Light current 14:48, 7 September 2006 (UTC)

For me the only real "pro" is the patient. If you have trouble seeing, you need glasses. It doesn't matter how "weak" your prescription would be. I wear glasses with such a weak prescription (-.50 left, -.75 right) that when my friends try them on for fun they just look like clear glass to them and they find it hard to understand what I need them for. Yet for me the difference is HUGE. Without them everything is fuzzy and with them everything is crystal clear.

As for buying cheap glasses at a drugstore, there are a whole bunch of reasons not to, but by far one of the most important is the fact that these places only tend to sell glasses to correct for presbyopia or "far-sightedness". Since I'm assuming you're rather young (being in school and all), I'm assuming that like me, you've got the opposite: myopia or "near-sightedness". Presbyopia tends to happen to practically everybody as they age. When older people start to have trouble reading small print, they get reading glasses. These are the types that are sold in drugstores. They always have "plus" prescriptions (as in +1, +2, +2.5 etc...designed for presbyopia) and also, they always assume both eyes are in equal condition. You'll never find a pair that are, for example, +2 right, +3 left. My guess is that you're like me and you're not presbyopic at all, but rather slightly myopic. That means that your glasses would have to have a "minus" prescription. It's easy to tell the difference. If you don't have any trouble with "up-close" things like reading, but have a lot of trouble seeing things that are further away, like the tv or or the blackboard or recognizing a friend from across the street, that means you're myopic, and besides being bad for you, those drugstore glasses wouldn't even be of any help...if you wore them they'd probably make things even fuzzier.

In any case, go to your eye doctor, and just be firm about it. Tell him or her that you can't see well, (and, if true, throwing in a bit about how you have trouble reading the blackboard would definitely help, nobody wants to have students who can't read the blackboard because they have a stupid doctor!) and that you NEED glasses. If s/he doesn't cooperate, see another doctor. If that doesn't work, talk to the folks at school where you failed the eye tests, I'm sure they'd be a lot more sympathetic. Good luck! Loomis 23:28, 8 September 2006 (UTC)

OK Let me put this another way. Why is there such a difference in the school eye exam and the optometrists results? Can this minor correction really be necessary for children, when it obviously isnt for adults?--Light current 18:03, 9 September 2006 (UTC)

When I was 10 years old, I was told I'd need glasses when I came to start driving. At 17, I went, and was told my eyesight was practically perfect - but since they were free on the NHS, she would still prescribe the -.25 my left eye could use (seriously, one eye being .25 out is the minimum wrong that they're capable of detecting). If you're having trouble seeing, and need it corrected, try for a second opinion. If you've just been told by someone that you'll need them in the future, see if time sorts it out. There's certainly absolutely nothing to be gained by purposefully damaging your vision. If you're desperate to start wearing glasses, you could pay for some with flat glass in both eyes, but if people ask you why you're wearing them, that could be an interesting conversation. --Mnemeson 23:50, 9 September 2006 (UTC)

September 7

Value of chemical elements

I noticed that the value of germanium in 1997 and 2000 was provided in that article. That sparked the question: what is the best source for determining the current value of such commodities? Is there a reliable web source for finding this information. Much thanks in advance. I'd like to find a consistent source for updating this aspect of the chemical articles. LeyteWolfer 05:57, 7 September 2006 (UTC)

'Spot' markets/commodity markets deal with commonly traded elements. There is data available on rare elements, I saw it recently (osmium data I think, and from a US govt source (less certain abt this)), but I can't remember where. That doesn't help at all, does it? Rentwa 06:53, 7 September 2006 (UTC)

No, I'm afraid not, but thanks for trying. LeyteWolfer 22:22, 7 September 2006 (UTC)

The USGS Mineral Commodities Summaries, here [13] generally include average prices for the years of the reports. Geologyguy 20:05, 8 September 2006 (UTC)

Geologyguy, you, my friend, are a god amongst men. Thanks a lot. LeyteWolfer 18:22, 9 September 2006 (UTC)

Weight versus elevation.

As you go farther from the center of the Earth, your weight decreases due to a weaker acceleration. How much does your weight alter from the Earth from an increase or decrease in elevation? Say I move from a place of lower elevation to a place of an increase in 500 feet of elevation. About how many pounds theoretically did I lose in weight? -User:NealIRC 7 September 2006 2:05 (UT)

Try staring at Newton's inverse-square force law, and think about the radius of the Earth. Melchoir 02:00, 7 September 2006 (UTC)

It's more complex than one would think, since you can't view the mass of the Earth as a point mass at the center until you are tens of thousands of miles into space. Instead, the mass of each atom, whether solid, liquid (water), or gas (air), must be considered, along with your distance from each atom. I've heard that the force of gravity actually increases slightly when you gain a little bit of altitude, due to the added mass of air below you pulling you down and the reduced mass of air above you pulling you up. StuRat 02:28, 7 September 2006 (UTC)

If we can approximate the physical earth as a nested collection of spherically symmetrical homogeneous shells, then the point mass simplification is fully equivalent for Newtonian physics as long as you stay on the outside. --Lambiam^Talk 02:53, 7 September 2006 (UTC)

Melchior and Lambian are right. It's easy to calculate. Clarityfiend 04:05, 7 September 2006 (UTC)

No, because the atmosphere does count. While it's mass is far less, it is far closer, if you are, say 1 km off the ground, so still has a rather significant effect on the net gravitational effect. Only after you are completely outside the atmosphere would such as approximation become accurate. The density of the Earth is also far from constant, which makes the point-mass model less accurate. See shell theorem for more detail. StuRat 04:20, 7 September 2006 (UTC)

Actually, as long as the density profile is spherically symmetric, the point-mass model is still good. As for the atmosphere... anyone want to crunch numbers on the two competing effects? Melchoir 04:25, 7 September 2006 (UTC)

The atmosphere has no significant effect, since the gravitational force falls off as r squared. There just isn't enough mass close enough to do much. Also, the non-symmetric density of the Earth doesn't really affect things either. The fact is there is a point where, if all the mass of the Earth were concentrated there, you would feel the same gravitational pull. For purposes of the original question, that's good enough. The non-homogeneity might move it a few miles one way or another (the oblate spheroid shape of the Earth too), but who cares? Compared to the distance between the point and the surface, it's negligible. Unless you're looking for ultra-accuracy, Newton's equation will give you a pretty good answer.

Here's a few rough numbers for the effect of the atmosphere (using ballpark figures, but they will give a very loose upper limit). At 120 km up, according to the wikipedia article, an astronaut notices the atmosphere upon reentry, so let's use that. The density of air at sea level is 1.2 kg/m cubed (sorry, don't know how to do superscripts). So a half sphere surrounding our intrepid questioner would mass about 10 to the 15th kg if the density didn't drop off as you go up; for simplicity, I'm going to use that figure. I don't want to go through and have to integrate that, so let's use an average distance of say 1 km. Crunch the numbers and you get about 0.07 Newtons. That's making the terrible assumption that the gravitational force is all in one direction, which it isn't. Even with all the simplifications grossly inflating the force, that's really, really miniscule.

Finally, you'd get a 1% decrease in weight when you are about 30 km further up (roughly - I only have the Windows calculator to work with). Clarityfiend 05:02, 7 September 2006 (UTC)

Again assuming spherical symmetry, the atmosphere does not contribute to the gravitational acceleration experienced by a body on the surface. In general, for a body at distance R from the centre, only the part within a sphere of radius R around the centre contributes to the net gravitational effect. --Lambiam^Talk 09:48, 7 September 2006 (UTC)

On the other hand, whether you are close to the equator or near the poles makes a more important difference in your weight because of the centrifugal force. A quick calculation yields that if you are at latitude φ, the g acceleration you actually feel is reduced by approximately 8.544*10^-4 m s^-2 * cos² φ. This means that if you travel from the poles to the equator, your weight will change by, say, 7 grams. If you travel only within the country it can barely be more than one or two grams. That's however still comparable to the difference you get from the altitude difference above. – b_jonas 08:43, 7 September 2006 (UTC)

The gravitational force is inversely related to the distance squared. So if the distance doubles, the gravitational force is reduced to 1/4. More in general, you should divide the two distances. Assuming Earth can be treated as a point mass at the centre of the actual Earth (so at a distance of about 6000 km), then if you go up 1 km, the distance increases by 6001/6000 = 1,00016666, so the gravitational force decreases to (6000/6001)² = 0,999666 of what it was. Earth's gravity says "an increase in altitude from sea level to the top of Mount Everest (8,850 metres) causes a weight decrease of about 0.28%". Let's do the math again, this time with the more accurate radius of 6372,8 km. (6372,8/(6372,8+8,85))² = 0,997228346. That's a decrease of about 0,0028. Or 28%. So either we're both right or we're both wrong or this is some weird coincidence. :) So if you weigh 100 kg (which I hope not), your weight will decrease by 280 grams when standing on top of mount Everest. That's about the weight of a meal.

500 feet is about 150 m, so that would then be something like a few grammes of weight 'loss'. You do the math. DirkvdM 09:14, 7 September 2006 (UTC)

That's not a meal for a 100 kg person, more like an appetizer. :-) StuRat 09:18, 7 September 2006 (UTC)

Carbon dioxide

With the growing scare in some social circles of the changing temperature on earth, carbon dioxide is constantly brought up as a greenhouse gas that needs to be cut down on. My question is would it be possible to somehow suck (extract) carbon dioxide from the atmosphere and put it in a solid state? - Tutmosis 01:23, 7 September 2006 (UTC)

Try Carbon dioxide sink#Artificial sequestration and Carbon capture and storage. Melchoir 01:27, 7 September 2006 (UTC)

There's way too much in the air for us to ever remove a significant portion with machinery. However, natural removal of carbon dioxide could be increased by increasing the number of land and/or sea plants. For example, algae growth could be encouraged by adding iron to iron-poor sea water. StuRat 02:22, 7 September 2006 (UTC)

I think that's been tried (dumping iron in the sea that is). I think I read about it in Discover magazine; can't remember exactly, but I think it didn't work out too well. (P.S. I think therefore I'm really not certain.) Clarityfiend 04:11, 7 September 2006 (UTC)

You are uncertain, therefore you are. DirkvdM 10:39, 7 September 2006 (UTC)

Yes it has been tried, with mixed interpretations regarding the outcome. More information and links to some of the studies can be found in the articles on Iron fertilization and Iron fertilizing (it has been suggested to merge the two articles). ---Sluzzelin 09:38, 7 September 2006 (UTC)

• There's an easy natural way of removing carbondioxide from the air which has the nice side effect of producing oxygen. It's called trees and if less of those were cut down and more of them were planted, things might be looking up... =- Mgm|^(talk) 07:23, 7 September 2006 (UTC)

See Carbon dioxide sink#Enhancing natural sequestration for that. Not just trees, but plants in general. But their presence alone doesn't do the trick. They need to grow to absorb carbon. So we need fast growing vegetation. Trees are a bad choice for that. Weeds would be better. Of course a useful weed (feel it coming?) would be best. Hemp is a good one. It grows extremely fast and has many uses. Burning it would undo the effect, so that's a bummer for the potheads. But it is also a good source for fibers. Actually, it used to be grown extensively throughout the world for that purpose (for the sailing industry for example), but got discredited because of its 'medicinal properties' (actually, DuPont pushed that to get rid of the competition for their plastic, but that's a differnt story). It also consumes a lot of Nitrogen, which is present in pig poo, of which we have an excess here in the Netherlands, so we would be an excellent choice for doing this (yeah, right, great excuse I hear you think, but its a different variety of the plant I'm talking about here). Another use is for oil, which can also be used as a fuel. That way it gets burned and the CO2 is released back into the atmosphere, anulling the effect, but if it is seen as an alternative to fossil fuels, no CO2 is added the atmospehere - the net result is zero. It's an oil so it should fit into the existing infrasturcture quite well. And the oil company that seems to be most into alternative fuels, Shell oil, is also Dutch, so I wonder if they're looking ito this. DirkvdM 10:39, 7 September 2006 (UTC)

Carbon was/is stored in a solid state in coal, and in a liquid state in oil. The problem is we're releasing that stored carbon. If we could just stop and wait a few million years, maybe more will be laid down... I wonder if, like coal, any solid form we found would be a good fuel, and thus potentially released by later generations? Skittle 10:57, 7 September 2006 (UTC)

I understand that diamonds will burn, under the proper circumstances, in case using $100 bills for toilet paper has lost all it's novelty. :-) StuRat 01:47, 9 September 2006 (UTC)

pray mantis

how do you identify the gender of a pray mantis insect

It's called a praying mantis. StuRat 01:33, 7 September 2006 (UTC)

Preying mantis might be better considering the following discussion. DirkvdM 10:51, 7 September 2006 (UTC)

Well, they are carnivores (insectivores, to be specific), so they do prey on other insects, but the name is due to their stance, which resembles the common praying stance for people. It's name is an interesting example of anthropomorphitization.StuRat 17:13, 7 September 2006 (UTC)

I believe if you know the species (which is very hard to do), then size plays a major role. I think females are much larger. --liquidGhoul 01:41, 7 September 2006 (UTC)

Size is the best way — [Mac Davis] (talk) (Desk|Help me improve)

Is it true that the female mantis sometimes eats the male after the dirty deed? Or is that a myth? That would be one rather final way of determining the male. Clarityfiend 04:08, 7 September 2006 (UTC)

The article's talk page has a bit of discussion on that. Given the commonness (is that a word?) of the story, the article really ought to address it one way or the other. Melchoir 04:18, 7 September 2006 (UTC)

As always, a great place to go for this kind of stuff is The Straight Dope. Do they have an answer for this one? Yes, they do. EWS23 (Leave me a message!) 05:08, 7 September 2006 (UTC)

Yuck! Thank god I'm not a praying mantis. Clarityfiend 05:53, 7 September 2006 (UTC)

Clarityfiend, you must have missed the article on precisely this topic in Tuesday's Science Times (a regular weekly feature of the New York Times). ---CH 07:52, 7 September 2006 (UTC)

I'm a typing man-tis, ready to figuratively bite off the heads of those who want to impregnate Wikipedia with their POV and lousy prose. Clarityfiend 16:36, 7 September 2006 (UTC)

Possibly I'm being pedantic, but size is only a partial answer, because it's only helpful when used as a comparative. If you had just one specimen of a particular type of praying mantis, (or, for that matter, several hundred all the same size) you wouldn't be able to tell if it was (they were all) male or female. Any other ideas? --Dweller 09:44, 7 September 2006 (UTC)

That's why I said you need to know the species, and obviously their sizes. The females are usually considerably large enough to differentiate. If you get a small praying mantis, it may just be a small species, not neccessarily a male. --liquidGhoul 09:49, 7 September 2006 (UTC)

Vivisection! — [Mac Davis] (talk) (Desk|Help me improve)

Water Ananlysis

Hi, I want to test drinking water with ref. to Hardness, Chloride content & free chlorine content pls. provide me the procedure for same however it should be volumetric analysis...

Thanks & Regards,

Anant BendigeriPatil. +919881271587.

Hmm, I can help you with the water hardness. Obtain samples, say 50ml, add 10ml ammonia and solochrome black indicator, and titrate with c. 0.01M EDTA. n(EDTA) will equal n(Ca) [a reasonable indicator of hardness]. BenC7 10:32, 7 September 2006 (UTC)

Cyclone/Tornado

I was wondering what the difference between a cyclone and a tornado is.Do cyclones have a funnel like tornadoes do?Andreamiller 10:43, 7 September 2006 (UTC)

This is an ancyclopedia. See cyclone and tornado. The main differences (I believe) are size and duration and the fact that cyclones start over sea. DirkvdM 10:54, 7 September 2006 (UTC)

Thanks,I did actually read both the articles.But my main question was whether cyclones had a funnel or not.Serenacw 10:58, 7 September 2006 (UTC)

No, in the usual sense of the word, a cyclone is a hurricane, which has an eye in the center, not a funnel. However, the word "cyclone" is misused to mean tornado in parts of the US. StuRat 12:02, 7 September 2006 (UTC)

To be fully correct (from cyclone):

Cyclones are responsible for a wide variety of different meteorological phenomena such as tropical cyclones and tornadoes.

So, a tornado is a form of / caused by a cyclone in the formal sense. All cyclones have a rotation, though not all will have "funnels" in the usual sense. And of course, Stu is absolutely correct about colloquial usage tending towards tropical cyclone. — Lomn | Talk 13:26, 7 September 2006 (UTC)

Molecule Diagrams

What are some good programs for drawing 2D molecules (especially organic ones)? What is generally used for Wikipedia? How about 3D molecules? Thanks --Russoc4 14:01, 7 September 2006 (UTC)

See the "Drawing molecules" section above. --Andreas Rejbrand 15:17, 7 September 2006 (UTC)

Oops...sorry. --Russoc4 16:19, 7 September 2006 (UTC)

donations to medical science

I am 80 years of age female (4 children)widow and have had several surgeries. at this time i have 6 incurable conditions in my brain. i think that would make my body a good prospect for worthwhile study. i asked my doctor how to do that and he said my drivers license. surely not! so i am asking help to find out how to donate my body to medical science at my graduation to heaven !

my email is (E-MAIL REMOVED) and my mail address is (ADDRESS REMOVED).

if you cannot help me, please suggest another place at whick i can inquuire for help. thank you

signed.................elaine harbour

Dear Elaine,

I think that your doctor was referring to the "donor" checkbox that many U.S. licenses have on them (in California, it is a little pink sticker; in Massachusetts, it is printed onto the license itself). Each state does it a little differently.

I've Googled around Oklahoma's donor options and haven't found one that works through the DMV though. The two best places to contact might be a company called LifeShareRegistry, which is specifically for organ donation but might know about other donor arrangements, and Oklahoma State University's Center for Health Sciences Body Donation Program. Both of these places could probably point you in the right direction in respects to Oklahoma's specific donor procedures. I commend you on your desire to aid medical science. Thank you. --Fastfission 14:37, 7 September 2006 (UTC)

Of course Elaine thinks she's going to get emailed or written to, so she's not actually likely to come back here (and would probably struggled to find her way back here if she wanted tó, if she's a Wikipedia noob). --Username132 (talk) 18:34, 7 September 2006 (UTC)

So who's going to be the good Samaritan and email her the link to her comment?  freshofftheufoΓΛĿЌ  02:32, 8 September 2006 (UTC)

• I'll do it if I can track down the email adress in the history. - Mgm|^(talk) 07:40, 8 September 2006 (UTC)

This diff. Delete it if you don't need it anymore.  freshofftheufoΓΛĿЌ  12:54, 8 September 2006 (UTC)

Why [is] glass transparent?

fixed by LeyteWolfer 17:08, 7 September 2006 (UTC)

See transparency and glass--Light current 17:12, 7 September 2006 (UTC)

Because if it weren't I wouldn't be able to read this. DirkvdM 18:59, 7 September 2006 (UTC)

And we all know the rules of the universe were written so that Dirk could do what he wants to do, when he wants to do it. ;o) EWS23 (Leave me a message!) 19:23, 7 September 2006 (UTC)

Haha! It's the anthropic principle. -- SCZenz 02:06, 8 September 2006 (UTC)

Indeed. We use glass because it's transparent. – b_jonas 21:11, 8 September 2006 (UTC)

Glass *Isn't* transparent. Use a Thermal IR camera to look around, and you'll find that glass is shiny and opaque, like a mirror. Now garbage bags, plastic shopping bags, etc., those this are totally transparent.

Sailors' Dead Winds

What are the things called where sailors would get stuck with out trade winds for days?

• Perhaps you are referring to the Doldrums? --Nebular110 17:54, 7 September 2006 (UTC)

• Doldrums. LeyteWolfer 17:54, 7 September 2006 (UTC)

No, that's a specific region where that phenomenon often occurs, but the question was for the name of the phenomenon. The answer is at the tip of my tongue, but can't break that barrier so to say. :) Then again, the question is specifically about the trade winds, so that's confusing. Anyway, that excludes the doldrums, because that is the area around the equator where there are no trade winds (if I understand it correctly). DirkvdM 19:11, 7 September 2006 (UTC)

I'd imagine the original poster was probably referring to the doldrums or the horse latitudes. If there's a word for the actual occurence of getting stuck there, as Dirk suggests, I haven't heard of it. EWS23 (Leave me a message!) 19:27, 7 September 2006 (UTC)

I'd say becalmed would be a fairly accurate description. GeeJo ^(t)⁄_(c) • 20:25, 7 September 2006 (UTC)

To be in the doldrums is to be becalmed surely?--Light current 02:37, 8 September 2006 (UTC)

Probably. But to be becalmed is not necessarily to be in the doldrums, particularly if you happen to be 1000 miles away at the time. JackofOz 04:04, 8 September 2006 (UTC)

Dead Calm

Handwashing

Can I hand wash clothes using regular (designed for washing machine) detergent, so long as I wear rubber gloves? --Username132 (talk) 18:26, 7 September 2006 (UTC)

I suppose you could, but liquid dish washing detergent works better for hand washing laundry. StuRat 18:48, 7 September 2006 (UTC)

Wouldn't that fade or otherwise damage the clothes? --Username132 (talk) 19:12, 7 September 2006 (UTC)

No, dishwashing detergent is much more gentle on clothes than laundry detergent, and some is even labeled "for use with delicate hand washables". The only concern might be that it would be less effective at removing serious stains, so I'd use a stain spray for that. StuRat 06:04, 8 September 2006 (UTC)

Yes you can, and personally I think laundry should be washed with laundry soap, and dishes should be washed with dish soap, and not vice-versa. :-) Anchoress 18:51, 7 September 2006 (UTC)

I have done that regularly when travelling. I supose it's not too good for the hands, so don't do it too often. Actually, in Cuba I got these areas of hardened skin that the doctor detected when I visited her for something else. It was easily soved with some ointment (can't remember what), but she told me to better not wash by hand. An overcautious doctor, I suppose. Funny StuRat mentions dishwashing detergent, because I use that for everything but my laundry (and my body). So I can now do away with the clotheswashing detergent as well? Less practical for travelling, though because it's a fluid and therefore too heavy. DirkvdM 19:16, 7 September 2006 (UTC)

You can use dishwashing detergent as emergency body soap and/or shampoo, too, but you need to dilute it with water first, or it's difficult to rinse off. I've used it myself when I ran out of the normal stuff, and it worked fine. StuRat 03:37, 10 September 2006 (UTC)

When traveling, I have used bath soap to wash clothes, and that works okay, too. It also doesn't really require gloves. Marco polo 19:43, 7 September 2006 (UTC)

Couldnt you do it by just having a bath with your clothes on?--Light current 01:41, 8 September 2006 (UTC)

Yes, but you're not going to enjoy the next thirty minutes in the dryer very much.--192.168.1.1 05:19, 8 September 2006 (UTC)

Actually, I met soneone who travelled with one set of clothing who did just that. In the tropics it can be wonderful to walk around in wet clothes. DirkvdM 07:07, 8 September 2006 (UTC)

Portal to define pictures of plants or animals

Hello, is here in the english Wikipedia a Portal to define pictures of unknown plants or animals, like in the german Wikipedia? Greetings --Ruestz 19:00, 7 September 2006 (UTC)

You could also upload to Wikimedia Commons (which is a better place to put photos because from there they can be accessed from any wiki project) and then place them at http://commons.wikimedia.org/wiki/Category:Unknown_species. try to put them in the most specific category you can find. Alternatively, ask at the most relevant talk page. By the way, the word is not 'define' but 'determine'. Wie auf Deutsch glaube ich, 'determinieren', nicht? DirkvdM 19:27, 7 September 2006 (UTC)

People usually just ask here, or on Wikipedia talk:WikiProject Tree of Life. There's no definitive place as far as i know. —Pengo ^{talk · contribs} 14:25, 9 September 2006 (UTC)

Thank You for the informations --Ruestz 22:32, 9 September 2006 (UTC)

Kuiper belt

The article states the majority of Kuiper belt objects were found after 1992, but it does not elaborate on why that is the case. Could someone please answer that, and place it in the article; as I feel the context would be helpful. - RoyBoy ⁸⁰⁰ 19:49, 7 September 2006 (UTC)

I'd speculate its because either:

• The technology required to see them was not yet available

• No-one looked in the right place at the right time with the right telescope

The reasons why someone didn't find/do something before anyone else is usually speculative and thus may be why it isn't in the article. Still, if anyone can source it... Rockpocket 01:31, 8 September 2006 (UTC)

I'd guess the Hubble Telescope, launched in 1990 and upgraded/corrected with COSTAR in 1993, was the source of this new data, as it was a major improvement over Earth-based optical telescopes. StuRat 05:53, 8 September 2006 (UTC)

I suspect that the Hubble isn't used explicitly for KBO surveys—it's field of view is too narrow and telescope time is too precious to go trolling for asteroids. It's possible that some might be discovered serendipitously while examining other objects. The HST can be used for examining these objects in (more) detail once they have been discovered, however. TenOfAllTrades(talk) 12:31, 8 September 2006 (UTC)

David C. Jewitt and Jane Luu discovered the first Kuiper Belt object in 1992 using a telescope in the Mauna Kea Observatory. Looks like people simply started looking for more. One of the larger KBOs, 90482 Orcus, can be seen in photographs from 1951 but nobody noticed it for fifty years (you can't just look at a photo and go "ha, a new planet!" You need to painstakingly compare many photographs from different times and detect tiny movements of very faint blobs to tell stars and moving rocks apart. You need to know what you are looking for.)

In a Scientific American May 1996 article Jewitt and Luu say that since the initial find a bunch of research groups have joined the effort and found a steady stream of KBOs. Weregerbil 08:46, 8 September 2006 (UTC)

When you mention Jewitt and Luu and 1992, you probably mean (15760) 1992 QB1. But that wasn't the first KBO found. As that article points out, Pluto was first, in 1930, and Charon second in 1978. QB1 was the third. -- Plutortalkcontribs 12:08, 8 September 2006 (UTC)

I think there is a distinction between "KBO found and known to be a KBO" and "discovering something which we now consider a KBO but was at the time considered a planet and a moon". --Fastfission 14:50, 8 September 2006 (UTC)

Indeed. In the last fifteen or twenty years there have been several major advances which have made searching for KBOs much easier. The computer hardware and software for automated image analysis (trying to find the one bright speck that isn't a star or known object) has gotten both better and cheaper. CCDs have become much cheaper and much improved in quality, allowing sky surveying without the messy intermediate steps involving photographic plates. Finally, several medium-large aperture telescopes (0.9 meters and up) have been configured for automated sky surveys in the last fifteen years—nobody's been looking very hard for KBOs until recently. TenOfAllTrades(talk) 12:31, 8 September 2006 (UTC)

One lung breathing

In the show Malcolm in the Middle, the character Stevie has (I think) only one lung and breathes a deep breath after every word. Is this medically correct? Reywas92 19:50, 7 September 2006 (UTC)

Stevie is chronically short of breath because he has severe asthma. I can't comment on the medical plausibility of his case, other than to say that if it were a fair clinical picture, Stevie would represent the more severe end of the chronic asthma spectrum.... TenOfAllTrades(talk) 21:50, 7 September 2006 (UTC)

• I doubt that is possible, Reywas92. One long is not enough to provide the body with the oxygen it needs and he would need to be on constant additional oxygen which he's not. - Mgm|^(talk) 07:36, 8 September 2006 (UTC)

Actually, one lung is enough to provide a person with the oxygen they need. Pneumonectomy (removal of one entire lung) is a surgical procedure for treating advanced lung cancer. Patients with one lung are limited to a modest level of physical activity, but otherwise can lead mostly normal lives. They don't need constant additional oxygen and are not confined to a wheel chair, like Stevie. --Ed (Edgar181) 13:07, 8 September 2006 (UTC)

Yeah, it's possible. Before modern antibiotics, tuberculosis was often treated by artificially collapsing one lung for a few days to create an environment unhospitible to the bacteria. With the plethora of new strains of resistant Tb, you may hear about this procedure in the future too...Tuckerekcut 04:25, 10 September 2006 (UTC)

The Guinness World Record: Bruce Geiling (born June 7, 1923) lost his right lung to cancer on April 10, 1969, and is still leading a healthy life on August 14, 2004. Neal 14:55, 10 September 2006 (UTC).

Can guinea pigs eat lettuce?

I read that iceberg lettuce is bad for guinea pigs. Is this true? Reywas92 19:52, 7 September 2006 (UTC)

Iceberg lettuce is pretty low in nutritional value—it's mostly "crunchy water". Neither guinea pigs nor humans get much out of the stuff; we only eat it because it's a convenient vehicle for salad dressings.

In larger quantities, the high water content and (probably) nitrates in the lettuce can cause various sorts of digestive upsets. Small amounts probably won't do any harm, but they're not beneficial either.

Consider something dark green and leafy, instead: kale, dandelion leaves, spinach, clover, or parsley. TenOfAllTrades(talk) 22:00, 7 September 2006 (UTC)

• We used to give our guinea pig nl:witlof. Unfortunately, there doesn't seem to be an English article on the stuf... - Mgm|^(talk) 07:35, 8 September 2006 (UTC)
  • That's Belgian endive. feydey 13:42, 8 September 2006 (UTC)

Yes. I don't know the mechanism behind it, but iceberg lettuce causes diarrhea and/or non-normal feces in guinea pigs and other animals. First hand info, I'm afraid - stick with romaine leffuce.  :-P As an aside, my daughter recently caught a caterpillar and when it refused some of the leafy stuff from outside, we stuck some iceberg lettuce in the terrarium for it - it also had loose feces. Not sure why *I* keep eating it... Matt Deres 19:28, 10 September 2006 (UTC)

How can I, as a white man get natty dreadlocks without having to pay for them?

I know that black ppl's hair naturally forms into dreadlocks if they don't brush or wash it for a long time. Is this true for white people too? How long would it take for the dreads to form if I decided never to touch my hair with anything again (it's already past shoulder length)? Some people might say it's gross to never wash your hair but I heard that the hair starts cleaning itself naturally after a while anyway.

I don't want salon dreads. I can't afford them.

It's not whether or not you wash your hair, it's whether or not you comb it. Here's an article called How To Make Dreadlocks and How To Make Dreadlocks - tips. Maybe that will help. Anchoress 21:34, 7 September 2006 (UTC)

Just completely ignore your hair.. I mean wash it and stuff, but don't hair care it, and it will matt. When it's matted just pull the matt into strands as thick as you want your dreads. Philc _T^E_C^I 21:37, 7 September 2006 (UTC)

So can Chinese people get dreadlocks than? It doens't sound right. — [Mac Davis] (talk) (Desk|Help me improve)

Sure, if they have hair that isn't straight. "It doesn't sound right" because you're not used to it, but I'm sure there are at least a few. ColourBurst 18:41, 8 September 2006 (UTC)

I once met a guy who after hiking through the Tasmanian bush for a few days noticed he couldn't get a comb through his hair. So it was either cut the hair or develop dreadlocks. he chose the latter. I believe something similar happened to Keith Richard.

Yup, it's a matter of not combing your hair. I just wonder if you can 'sculpture' the dreadlocks. What if a dreadlock develops you don't like? Some look messy, others look neat, is there a trick to that? And bums nowadays often have dreadlocks, which makes sense, so it doesn't make sense that that would be a recent phenomemon. So did they have them in previous centuries too? DirkvdM 07:19, 8 September 2006 (UTC)

I haven't combed/brushed my hair in years, and I don't have light, straight hair. I also don't generally "treat" it, just shampoo and the monthly conditioner or so. I had a roommate up until a couple of months ago with huge dreads, and although he washed them, I don't think he did very often. Something like, "When I start to smell it too, that's when I wash".  freshofftheufoΓΛĿЌ  07:28, 8 September 2006 (UTC)

One of us has a nephew who just put toothpaste in his hair. dreadful it was, but it was quite dreadlockish. -- DLL ^{.. T} 16:26, 9 September 2006 (UTC)

What if you don't brush your teeth for a long time? Will you get dreadful teeth then? I suppose so. DirkvdM 08:02, 10 September 2006 (UTC)

Sodium vs sodium chloride in foods

When a food label in the US (FDA regulated) claims sodium content, do they really mean sodium chloride as in traditional edible salt or is this the mass of any digestible form of sodium in the food? As a follow-up, does the human body use sodium or sodium chloride specifically to regulate hydration? When reading over the articles, it's hard to tell if terms are used loosely. p.s. this isn't homework, I swear! --Jmeden2000 21:31, 7 September 2006 (UTC)

As to the first question, my guess is they really mean sodium, but it's just a guess. The second question I can answer a bit more definitively: When sodium chloride is dissolved in water (as it will be in your body) it dissociates almost completely. So what counts is sodium ion, Na⁺; your body has no way of knowing if it was part of sodium chloride or some other sodium salt. --Trovatore 21:39, 7 September 2006 (UTC)

THe main source of sodium in the diet must be sodium chloride. I cant think of any other sodium salts that we eat in any quantity.--Light current 22:24, 7 September 2006 (UTC)

edit conflict: yeah they mean total sodium content, from salt, baking soda preservatives etc. because it's all sodium in the end. the sodium ion is important, for example in the Na+/K+-ATPase. not to say chloride isn't important too. and i think they measure sodium due to its role in heart disease, but i'm unsure. Xcomradex 22:29, 7 September 2006 (UTC)

and just for light current: sodium bicarbonate, sodium benzoate, monosodium glutamate... Xcomradex 22:29, 7 September 2006 (UTC)

Apart from monosodium glute a mate (used as flavor enhancer). How much sodium bicarb and sodium bezoate do we eat?--Light current 22:33, 7 September 2006 (UTC)

• sodium benzoate: FDA maximum of 0.1% w/w
• sodium bicarbonate: from cookbooks seems about one teaspoon (5g)/ cake

bear in mind we don't usually put a lot of salt on meals in w/w terms. but is still probably the major source, due to its ubiquity. Xcomradex 23:08, 7 September 2006 (UTC)

1gm NaCl contains 0.4 gm sodium--Light current 23:31, 7 September 2006 (UTC)

it does, but remember we don't put 1g salt on a 100g steak. Xcomradex 01:06, 8 September 2006 (UTC)

I dont put any on. But there again I dont eat steak.--Light current 01:08, 8 September 2006 (UTC)

By the way, the unit sign of "gram" is g. gm is "mostly obsolete" when referring to grams, unless you were actually talking about giga-meters.  freshofftheufoΓΛĿЌ  02:24, 8 September 2006 (UTC)

Gm is used for Gigameters. StuRat 00:42, 10 September 2006 (UTC)

THanks for that 8-)--Light current 02:25, 8 September 2006 (UTC)

Sodium is what's used for hydration. Chloride is the most important anion in the body because it is the most common. However, the sodium is what's regulated and the chloride usually just follows! InvictaHOG 09:56, 8 September 2006 (UTC)

Follow up

First of all thank you to all who answered, this has been most informative. I would like to add another sub question: how do you suppose all animals developed a heavy reliance on sodium if it is so rare to occur in plants? (as per the sodium article). Surely primitive mammals were not digging salt mines or evaporating sea water... So where in the food chain does it all come from? --Jmeden2000 17:22, 8 September 2006 (UTC)

Salt lick. --Serie 19:34, 8 September 2006 (UTC)

While life evolved in the ocean, where there is plenty of salt, I agree that it does seem odd that, once animals moved onto land where salt is scarce, they weren't able to evolve to better match this low salt diet. I would have to conclude that it's just extremely difficult to break this dependency. StuRat 21:42, 8 September 2006 (UTC)

thats right sturat. the sodium ions are used to produce a concentration gradient across the cell membrane, which then allows essential compopunds such as amino acids to be brought into the cell and concentrated by active transport, with the change in sodium concentration making the whole process positive in entropy terms. the system is of such a fundamental importance, i'd doubt whether the necessary genetic variation could exist for evolution to occur. Xcomradex 22:39, 8 September 2006 (UTC)

I thought it might be useful to add sodium sturate in a regular diet. -- DLL ^{.. T} 15:21, 9 September 2006 (UTC)

Mutism

I recently watched a TV drama in which one of the main characters got in some kind of accident and lost her hearing. She chose to start using sign language exclusively because she couldn't hear the sound of her voice and was ashamed about the way she assumed it would sound. That said she did talk occasionally during the show, with a very nasal voice, the kind one might usually associate with a person unable to hear from birth. I'm not sure how realistic the drama is supposed to be, but I'd be a little shocked if there was such a big misconception as that. Do (could) people who become deaf (suddenly?) lose the ability to speak in a fashion that they were able to before they became deaf? I couldn't find any mention of it at speech disorder or deaf culture.  freshofftheufoΓΛĿЌ  22:21, 7 September 2006 (UTC)

I've heard radio-interviews with people who lost their hearing and their speech was completely 'normal' and melodious to my ears. Singing, where the frequencies and modulations have to be more accurate, is a different thing; I distinctly remember listening to a woman who had lost her hearing years ago sing Amazing Grace, and it was hard to recognize the melody. Percussionist Evelyn Glennie almost entirely lost her hearing at the age of twelve and speaks like a hearing Scottish person too, as can be heard in the documentary film Touch The Sound. ---Sluzzelin 05:59, 8 September 2006 (UTC)

The problem with that, I guess, is that deafness usually isn't absolute, and at least some of the people you mentioned might have some awareness of the sounds coming from inside their bodies (Evelyn Glennie's article notes that she has "very limited hearing"). Failing that, it seems that at the very least it may not be expected for someone to lose the ability to speak properly along with their hearing, though I wonder if there are exceptions. I actually quite liked the drama so I kind of want it to not be a complete farce!  freshofftheufoΓΛĿЌ  07:11, 8 September 2006 (UTC)

This is also why singers (and instrumentalists for that matter) need feedback through a monitor on stage. If they can't hear their own voice they can't sing in tune. I wonder if classical singers before a full orchestra (which can be a lot louder than a rock band) use this too. I don't recall ever seeing it. DirkvdM 07:25, 8 September 2006 (UTC)

No they dont. THey can belt it out at much higher levels than pop singers so they can hear themslves ok. Also the orch tends to come down under the singer a bit.--Light current 07:38, 8 September 2006 (UTC)

(Edit conflict) You're right. And a further difference to the TV drama, is that most people lose their hearing gradually, allowing them to closely monitor and correct changes in their speech. Googling "traumatic mutism" or "post-traumatic mutism" leads you to some neurological websites discussing this phenomenon. In the cases I found, mutism was explained psychologically and not linked to the loss of sense of hearing.---Sluzzelin 07:34, 8 September 2006 (UTC)

Ok ok, but I'm losing the original question. I don't think there was any post-traumatic mutism or anything like that, the show explained her "nasal speech" to the extent that it was only a concequence of her loss of hearing, which in turn was caused by some sort of car accident I think. Anyway, I think it's pretty clear that this drama was a little bit scrubbier than I initially thought. Loss of tone recognition doesn't really explain either why she would suddenly sound nasal. Oh well, thanks guys!  freshofftheufoΓΛĿЌ  12:03, 8 September 2006 (UTC)

September 8

How large are the Mars rovers?

I'm curious to know the dimensions of the Opportunity and Spirit Mars rovers. I can't seem to find these specs on the Internet. Thanks!

Cruise vehicle dimensions: 2.65 meters (8.7 feet) diameter, 1.6 meters (5.2 feet) tall Rover dimensions: 1.5 meter (4.9 feet) high by 2.3 meters (7.5 feet) wide by 1.6 meter (5.2 feet) long

Weight: 1,062 kilograms (2,341 pounds) total at launch, consisting of 174-kilogram (384- pound) rover, 365-kilogram (805-pound) lander, 198-kilogram (436-pound) backshell and parachute, 90-kilogram (198-pound) heat shield and 183-kilogram (403-pound) cruise stage, plus 52 kilograms (115 pounds) of propellant

From mars tv. Also, check out Mars Exploration Rover ---Sluzzelin 06:51, 8 September 2006 (UTC)

Useful fictions inside of science

What are some useful fictions that have been created for calculational purposes similar to a center of mass/gravity? A center of gravity isn't an actual feature of matter, just something we impose upon matter in order to help make our calculations easier for a given system. Thanks--droptone 12:32, 8 September 2006 (UTC)

See WP's articles on mathematical models in physics, and on theory. ---Sluzzelin 12:48, 8 September 2006 (UTC)

That reminds me of a joke my boss once told me about calculating the surface area of a chicken. First you assume that it's a perfect sphere... – ClockworkSoul 12:53, 8 September 2006 (UTC)

I remember this book: Consider a spherical Cow was quite popular a while back.---Sluzzelin 13:05, 8 September 2006 (UTC)

Depends how broad you want to make you definition of fiction. You could say that energy and entropy are useful fictions, since you can't measure them directly - you have to infer them from other properties of an object or system. And temperature, pressure, density and viscosity are all average measures that only make sense for a large population of atoms or molecules, so you could argue that they are also fictions. Velocity depends on your frame of reference, so maybe that is a fiction too. In fact, the only properties that are truly "features" of elementary particles seem to be spin, charge and mass. Gandalf61 14:45, 8 September 2006 (UTC)

• Newtonian physics is technically wrong, in that it doesn't account for relativity, but still widely used for most calculations.

• The Dalton model of the atom, while useful for basic chemistry, is not as useful in particle physics.

• Planetary and lunar orbits are approximated as ellipses, while the true orbits must account for various perturbations.

• The "no air resistance" model of ballistics.

StuRat 19:35, 8 September 2006 (UTC)

Body Mass Index assumes every human has an identical body shape, but is effectively used to determine obesity. While it could be improved by using body shapes or even getting an extremely accurate BMI by weighing people in water, the difference between BMI and the highly accurate indexes is statistically insignificant for nearly all people. --Kainaw ^(talk) 20:12, 8 September 2006 (UTC)

By fictions do you mean specifically fictitious entities that we postulate in science, or just any (probably false) assumption made in a scientific theory? Lumping the two together, here are a few:

1. The perfect rationality assumption used in the Homo economicus model of human behavior is often defended as a useful fiction.
2. Infinite populations are often used in evolutionary game theory and population genetics models in biology, these are certainly false assumptions. (There's actually a list at replicator dynamics.)
3. The use of frictionless planes in physics. (Or really just about any calculation done in an intro physics class and most engineering classes.)
4. Point particles used in Newtonian mechanics, special relativity, and general relativity.
5. Fluid dynamics assumes that fluids are continuous, they're not.

I attended a talk recently about use of fictions in computer simulation modeling, the video is archived here (its the second talk). As I recall he makes a distinction between "fictions" and "modeling assumptions." But he has a bunch of interesting examples. --best, kevin [kzollman][talk] 22:00, 8 September 2006 (UTC)

Chicken? Cow? Feynmann always called it a horse. — [Mac Davis] (talk) (Desk|Help me improve)

Isn't any unit an abstraction and therefore fiction? An object doensn't have any metres in it, length is a quality we assign to it. In more practical terms, what is your height? One part of this is the issue of precision. Any measurement is an approximation and therefore not exact. So is it real? But there is also the definition of someone's length. Do you include the hair on your head (if any)? If so, is it combed? What about the length of a punk with a Mohawk hairstyle? Converrsely, the centre of gravity is just as real as the geometric centre and therefore the radius of a planet (another use of the quantity 'length'). DirkvdM 12:41, 9 September 2006 (UTC)

Help to identify spider

Hello, can someone please tell me what spider this is? Or at least if it is poisonous? Sorry for the bad pic but I only had my cellphone camera available at the time. I live in Gauteng, South Africa. I am afraid for my children's safety. The spider is about as big as a toddler's hand. One enters our house every week or so. If I wave an object like a broom near it, it raises its front legs (?) towards the object. Is this a defensive or aggressive pose? Sandman30s 14:13, 8 September 2006 (UTC)

That picture really isn't very much to go on. I believe, in general, that when a spider raises its front legs it is generally an aggressive, "Look at my teeth" pose, but I only know about Australian spiders in that respect. This page contains pictures of some of the more "medically important" spiders of South Africa that you can compare it with. Apparently South Africa also has trapdoor spiders and baboon spiders, neither of which would be very fun to get bitten by. Again, I'm not a spider expert in any respect, though. If I had to guess by the picture alone, the long-legs, big-head would make me worry that it was a violin spider, which have poisonous (but not always deadly) bites. I would definitely try to kill it in any case—a shovel would be my method of dispatching it, personally. --Fastfission 14:43, 8 September 2006 (UTC)

Thanks very much for the detailed answer. My best guess from all those pictures is the lesser baboon spider (HARPACTIRELLA), it doesn't look like the violin spider due to a different colour, unless the violin is also dark brown with dark red and black legs. I will try to get a better pic the next time, sorry. Also if the spider is not poisonous, I would not like to affect the ecosystem around the house, as the spiders would reduce my overpopulation of crickets :)

I'd much rather have the crickets. :-) StuRat 19:21, 8 September 2006 (UTC)

Not to be too much of a pedant, but all spiders are venomous. I have no idea whether this particular spider is dangerous, however. --Ginkgo100 ^{talk · e@} 20:18, 8 September 2006 (UTC)

Are you sure? I remember that that was some sort of urban myth. I'd check Snopes if I had the time. - Mgm|^(talk) 20:45, 8 September 2006 (UTC)

Correction to the above from spider: there are a few species not able to inject venom. --Ginkgo100 ^{talk · e@} 20:23, 8 September 2006 (UTC)

Really, there are only a few, as in 14 or less if I recall correctly, and they all live in remote regions of the jungle. I created two articles, and some redirects a while ago, when a new species was discovered that did not have any venom. Instead, it traps prey in it's web, then bundles it up, tigtens the cords until the prey is broken to pieces. The spider proceeds on to regurgitate digestive juices, pour them onto the prey, wait, then feast. — [Mac Davis] (talk) (Desk|Help me improve)

Looks like a "jagspinnekop" (Palystes sp. - African hunting spider), especially as you mention the striped legs, and the very typical raising of the front legs when threatened. The raised legs are impressive, but only a show - it does not attack that way. It hunts at night, and has no web as such, just a nest which takes 2-3 days to build. Though one cannot judge size, it looks like a youngster you have there (inter alia it still has 8 legs!). Also called a "reënspinnekop", (rain spider) from it's alleged habit of appearing inside when rain threatens. This spiders's bite hurts like a bee-sting, but won't kill - unless you get a heart attack from fright. It normally runs away - very fast once it starts running - to a dark corner somewhere. If you have trees outside (or dense bushes or ivy on a wall) you may find its large fist-sized nest of leaves, twigs and silk hanging inside the denser growth - be cautious, the female guards the nest. I leave them be, they don't build nests inside your house, and I've watched them catch other goggas inside at night. They definitely eat crickets, but there is no way they will prevent the periodic "cricket epidemics". If you wish to catch it, it is legal to keep it, and you can handle it if you don't mind an occasional bee-sting-bad bite. Contact a museum to find the correct diet, etc. The site also gives advice on how to catch it and return it outside. I normally use a plastic shopping bag which I place over it and then coax it into the bag, trying not to hurt the legs, then leave the bag open in a tree. The "bobbejaanspinnekop" (Harpactira/ella you mentioned - Therasophidae - Baboonspider) is bulkier, legs relatively shorter and oriented differently, more hairy, does not show the clear markings you mention, does not typically show that same threatening stance, and is a protected species, because of a demand as "pets" in the first world countries. Searching the web for "rain spider" or "hunting spider" should give the best results if you want to know more. --Seejyb 20:55, 8 September 2006 (UTC)

Still hard to identify but looks very much like the second pic on this page you talked about - the huntsman. These things become absolute monsters (size of adult hand) and don't seem infected by normal insecticide - will given it's not an insect :) Good to know it's not worse than a bee sting. Will definitely get a better pic next time to get a proper ID. And for the record - I freakin HATE CRICKETS! Their incessant ventriloquist chirping interferes with some frequency in my brain and I cannot sleep and cannot find the little buggers, in the day or night! GRRR. And to make it worse we get 'Parktown Prawns' (King Crickets) where I live - harmless but they have to be the ugliest darn things alive (good at hiding too). Ugh. Sandman30s 22:26, 8 September 2006 (UTC)

Cats are good at catching crickets. User:Zoe|(talk) 23:19, 8 September 2006 (UTC)

Sounds like a much better choice to me. StuRat 01:22, 9 September 2006 (UTC)

Yeah, I would say it's a huntsman. We have plenty of them in Australia. They tend not to be aggressive, as you can see from the article page. BenC7 09:06, 9 September 2006 (UTC)

diabetes in cats

Can someone please advise what choices for cats are available? My vet is at a loss as to bringing down the insulin level. i've tried humulin u, humulin m, and nothing works. i'm getting pretty desperate.

Try feline diabetes and the wiki on pet diabetes for further links and references. Please understand that we can't give medical advice at the reference desk. Good luck and all the best to your feline friend. ---Sluzzelin 14:55, 8 September 2006 (UTC)

I have been using PZI with my cat with some success, my vet says she prefers it to humulin. In addition, putting them on a low carbohydrate diet is considered important and has resulted in a reversal of diabetes for some cats. My cat is on Hill's Prescription M/D. Of course, this is only one case, and I'm not a vet. --best, kevin [kzollman][talk] 21:39, 8 September 2006 (UTC)

ribose sugar

Is a ribose sugar a reducing sugar

Look at the structure of ribose and see if it contains the substructures or other features that are consistent with those of a reducing sugar. DMacks 15:10, 8 September 2006 (UTC)

Paraffin lanterns & alcohol

Would it be possible to safely run a paraffin lantern on alcohol if you haven't got any paraffin handy? If not what could you run it on that doesn't need to be obtained from hydrocarbons. AllanHainey 15:35, 8 September 2006 (UTC)

Paraffin is a solid hydrocarbon while ethanol is a liquid alcohol. Because it's not really the solid wax of paraffin that burns, but rather the resulting liquid/gas, if your lamp can accomodate a liquid fuel, it may be able to run properly.--Russoc4 17:47, 8 September 2006 (UTC)

In the UK, paraffin is a liquid fuel, and paraffin wax is a solid - the constituent of candles. --G N Frykman 17:54, 8 September 2006 (UTC)

Forgot about that...well, ethanol may or may not work properly. I found a very indepth page [14] describing and comparing many fuels that can be used in camping stoves. The same applies here, only the fuel has to travel through a wick. The only problem I can forsee with ethanol is that it boils relatively easily. It's also less efficient when comparing BTUs/lb. isopropyl rubbing alcohol is not recommended. --Russoc4 19:04, 8 September 2006 (UTC)

I'd tend to recommend strongly against the use of ethanol in a lantern. Ethanol burns with a hotter, bluer flame that doesn't generate much light and will be harder on your lamp hardware. In addition, it has a higher vapour pressure (meaning that heating it during lamp operation may result in various sorts of failure of your lamp, some quite dramatic) and lower flashpoint. TenOfAllTrades(talk) 21:15, 8 September 2006 (UTC)

I presume you are talking about a non-pressurised, wick-burning system. Alcohol, petrol, lighter fluid or any similar fuel will not be safe in a lantern designed for paraffin - you will create a fireball, if not an explosion. The machine is not designed to handle such highly volatile substances. In practice, a light vegetable oil does work, but it stinks. Turpentine should be a safe option, and also stinks. --Seejyb 22:01, 8 September 2006 (UTC)

Burn!!

It's my understanding that when you burn organics like wood, or sucrose, the impurities of water and smoke components are burned off leaving residual carbon behind. If this is true, why does this residue not continue to burn? Doesn't carbon oxidize to form CO2? --Russoc4 17:42, 8 September 2006 (UTC)

See charcoal--Light current 17:44, 8 September 2006 (UTC)

Many people confuse heating and burning. See destructive distillation. --G N Frykman 18:00, 8 September 2006 (UTC)

Soot – which is mostly carbon – is the result of incomplete combustion of organic matter. As long as the fire remains hot and well-supplied with oxygen, the carbon will burn off to form carbon dioxide. (Under conditions of inadequate heat or oxygen, you may instead end up with carbon monoxide.) TenOfAllTrades(talk) 18:09, 8 September 2006 (UTC)

So charcoal/coke is made by "heating" wood/coal, but not actually burning it completely in enough oxygen. I get that part. You didn't answer my question. What I don't get is that when wood burns completely, it creates ash, which glows for some time, but then dies out. Why does it not burn if it's mostly carbon? --Russoc4 18:51, 8 September 2006 (UTC)

IT'S NOT CARBON. I don't know about your ashes, but the stuff in my fireplace looks like white fluffy powder, plus a few lumps of charred unburned wood. A better question is: why do very tiny pieces of charcoal stop burning? Or this: what is "wood ash's" composition? Google searches say: calcium carbonate, potassium carbonate, aluminum oxide, magnesium oxide, and lots of other stuff. In other words, the ashes are the traces of minerals used by the tree. See: [15] --Wjbeaty 23:41, 8 September 2006 (UTC)

Burning an organic material oxidizes it, leaving oxides of its component elements, the most common elements in organics are carbon hydrgoen and oxygen. I there is insufficient oxygen, you will be left with unoxidized elements. So hydrogen and carbon, you are unlikely to notice any hydrogen, and carbon is in the form of soot. Carbon needs the heat from the fire to form new bonds with oxygen, so will not spontaneously oxidize once oxygen is sufficient, so it will be left. Philc _T^E_C^I 21:04, 8 September 2006 (UTC)

Oh... well, that does clear some things up. So essentially, a burnt up, blackened matchstick has no carbon, just other random impurities. --Russoc4 13:56, 9 September 2006 (UTC)

Er, no. A blackened matchstick will be black (primarily) because of the remaining unburnt carbon. (White residue is mostly mineral impurities.) Overall, the process of combustion releases energy; we see this as heat and light. However, the reaction – in this case, the combustion of carbon to form carbon dioxide – requires a small amount of energy to get started. Normally combustion is self-sustaining once started; a small amount of heat from the reaction is fed back in to the system to drive the oxidation of more fuel. This feedback loop breaks down, however, if too much heat is drawn away from the fuel. That's why you can blow out a match—your breath cools down the fuel (paper or wood) in the matchstick, ending further combustion.

This is also why charcoal is so difficult to light. You have add (and ignite) lighter fluid to charcoal to supply adequate intial heat to start the charcoal burning. Once ignited, however, charcoal will burn very hot. TenOfAllTrades(talk) 14:16, 9 September 2006 (UTC)

Ahh... ic now. Thanks! --Russoc4 16:53, 9 September 2006 (UTC)

Aldol Compound

Can anyone help me out on this one? I'm trying to figure out the name of this compound that results from an aldol reaction. It is a yellow solid with a molecular formula of C₁₈H₁₆O₃, and its experimental melting point is 167°C to 172°C. ChemFinder is no help either, unless I'm not looking in the right spot. --Russoc4 20:05, 8 September 2006 (UTC)

File:Aldol.PNG

• Try if you can get your hands on a book like the Handbook of Chemistry and Physics, BINAS or if you happen to be able to read Dutch the "Chemiekaarten". I would also recommend you draw up the different compounds that could result with that molecular formula and make a guess at which it is by determining whether long chains have a lower/higher melting point and how saturation affects it. - Mgm|^(talk) 20:51, 8 September 2006 (UTC)
• If you do the guessing well it will reduce the number of compounds you need to look up. - Mgm|^(talk) 20:53, 8 September 2006 (UTC)

I considered the Handbook. If I have to, I'll use it. Thanks though. --Russoc4 21:00, 8 September 2006 (UTC)

chemfinder won't be any help. break the compound down into its components, you've got the indanone, an (E)-configured exo alkene, and a dimethoxy substituted benzene ring. start combining the pieces into names, such as (E) 2-(3',4'-dimethoxystyrl)indanone. not iupac, but it'll fly. alternatively if you want to go iupac, start breaking down the functional groups even further. In the real world, software like chemdraw has automated the naming of such compounds, and you'll often see things referred back to structures (eg indanone 1) in order to make life easier. sing out if i've lost at some point, it's hard to gauge what level you're on. Xcomradex 22:56, 8 September 2006 (UTC)

I purposely made it hard to tell :P I'm only in my 1st of 3 sememsters of organic chem. We did this in our second lab, and though I'm not sure if we really need to identify the name, it can't hurt. We did this to practice recrystallization. I'm a chemistry major, as you might tell from my user page, which also lists my classes :D. No biggie if I can't get a good name though, but thanks for your help! --Russoc4 02:42, 9 September 2006 (UTC)

i'd say they don't want you to name it in iupac terms, i'm up to six years (and counting) of org chem, and it still made me think. you'll pick up soon enough that iupac terms are just unwieldy for anything remotely complex. eg 2-[3,4-dihydroxy-2,5-bis(hydroxymethyl)tetrahydrofuran-2-yl]oxy-6-(hydroxymethyl)tetrahydropyran-3,4,5-triol is unrecognisable, and it only gets worse when include stereochemical descriptors. but tell any chemist 'sucrose' and they'll know what you're on about straight away. good on you for going the extra mile though, that'll get you good marks. Xcomradex 04:02, 9 September 2006 (UTC)

American passenger rail profitability

Why is it that, despite the commercial viability of passenger railways in Europe and Japan, American passenger rail has never turned a net profit since 1930, four decades before the founding of Amtrak? C. M. Harris ^{Talk to me} 20:09, 8 September 2006 (UTC)

Gasoline is far cheaper in the U.S. than in every European country I've been to (Norway, Sweden, Denmark, U.K., France, Italy, and Turkey). I assume it is cheaper than all of the European countries. While we complain about $3/gallon gas, a friend of mine in Italy is complaining about $10/gallon gas. Since gas is so cheap, there is no incentive for people in the U.S. to use the railroad, which even with the cheap tickets is still not much cheaper than driving. So, if ticket prices were increased to allow the rail to profit, nobody would want to ride. --Kainaw ^(talk) 20:21, 8 September 2006 (UTC)

What does "commercial viability" mean? I thought most non-US rail systems were government-subsidized... DMacks 20:37, 8 September 2006 (UTC)

Most rail systems are subsidised, as a lot of countries recognize the rail service not as a gold digging source of income for the government, but as a service, which the government helps provide, in exchange for all the taxes etc. Philc _T^E_C^I 21:00, 8 September 2006 (UTC)

in NZ we privatised the railways, and if you ever wanted an example of why you don't privatise a natural monopoly, Tranz Rail is it (and NZ's privitised telecomunications service Telecom New Zealand too). Tranz rail ran the NZ railways into the ground, closing line after line due to poor maintanence, let alone the asset stripping. Xcomradex 23:03, 8 September 2006 (UTC)

In addition to all the above, consider the problem of distance. Railways in European countries and Japan don't have to cover particularly large areas. The United States, on the other hand, is gigantic, spreading across an entire continent. It costs a lot more to operate a train from New York to Los Angeles than it does to run one from London to Edinburgh. On top of that, the trip takes several days, which is unacceptable to most Americans when they can fly the same distance in five or six hours. (Not that anything operated by the government could ever attain profitability, but that's a separate issue.) --Aaron 23:16, 8 September 2006 (UTC)

High speed rail (such as maglev) could solve the time problem, especially between populus, close cities, like the Boston/New York/Wshington DC corridor. Of course, in these days of rampant terrorism, the high speed line would need to be well protected, as it would be a natural target. StuRat 05:06, 9 September 2006 (UTC)

Railways have to compete with other modes of transportation and those are subsidised, so the railways have to be subsidised too to keep the prices down. In the case of airplanes it's obvious - they don't have to pay tax over the fuel. And I have once heard that (in the Netherlands at least) car travel is also subsidised for about 50%. I just don't know any further details on this, but I suppose road building and maintenance with general public funds in stead of just taxes relatedc to car driving is an important aspect. I also once heard that if people had to pay the real cost of driving a car, no-one would. DirkvdM 13:49, 9 September 2006 (UTC)

Jet fuel is taxed in the U.S. with different cities having different rates. Rmhermen 23:28, 9 September 2006 (UTC)

Various economic booms in Japan really helped to boost the rail industry, allowing the national rail company (and later, numerous privatized rail companies) to extend, improve, and add numerous lines leading to remote areas of the country, as well as improve the Shinkansen (bullet train services). Now that the infrastructure has long been a staple of modern Japanese life, I doubt even a major depression could cause much harm to the rail industry. I also doubt that Japan would be able to achieve such a feat again if they had to start now. You can see effects of the rail industry "dealing" with recent economic pressure by the age of a lot of the trains (many of the trains run by private companies are very Art Nouveau).  freshofftheufoΓΛĿЌ  16:04, 9 September 2006 (UTC)

grasshopper

how do you tell the difference between a grasshopper and a cricket?Kevinamccracke 22:22, 8 September 2006 (UTC)

Color ? Grasshoppers are typically brown or green, while crickets are usually black. StuRat 00:55, 9 September 2006 (UTC)

Follow StuRat's links and read that grasshoppers have short antennae and crickets have long ones. I used to mix the two up in the naming of my photographs until I read those articles. DirkvdM 13:50, 9 September 2006 (UTC)

Length of Time To Circumnavigate Globe

I did a Wikipedia and Google search, but to no avail.

If I utilized only:

• 1) Public Airports/Airplanes (No Private Jets)
• 2) Automobiles
• 3) Trains, Subways, Chunnel, etc.,
• 4) Boats, and
• 5) Human Powered Vechicles (Bicycle, etc.)

What is the absolute minimum time it would take to circumnavigate the globe?

Thanks, --69.138.61.168 23:28, 8 September 2006 (UTC)

It'll make a major different depending where you're starting from, and how much of a 'straight line' you want to do... if you take a boat in summer, you could circumnavigate around the north pole in five minutes... if you want to stick within ten miles of the equator at all times, it'll take significantly longer. --Mnemeson 23:34, 8 September 2006 (UTC)

Ha! I didn't even think about taking a boat around the North Pole. Good answer!

It will need to be a submarine or icebreaker, because the surface of the water at the North Pole is covered with ice. StuRat 00:52, 9 September 2006 (UTC)

probably 48 hours by plane. JFK - Narita - Heathrow - JFK--69.138.61.168 23:40, 8 September 2006 (UTC)

I agree with 48 hours, by plane. The only time you would need any other form of transport would be to get from terminal to terminal in the airports. StuRat 01:09, 9 September 2006 (UTC)

It took me 24-28 hours to get from Orlando International Airport to Bangkok International Airport. — [Mac Davis] (talk) (Desk|Help me improve)

Of course a plane would be fastest. If you are required to stick within a certain distance of the equator, you probably wouldn't find commercial flights to suit you. But if the requirements are less strict, an eastbound plane would be faster than a westward bound one because it could hitch a ride on the jet stream. On top of that, it would cross the international date line (as Phileas Fogg found out) and gain a day (or lose one, depending on how you look at it). DirkvdM 14:11, 9 September 2006 (UTC)

I would assume they want to know the actual elapsed time, so don't care about time zones or the date line. StuRat 00:34, 10 September 2006 (UTC)

A quick check with kayak.com shows that it's not unreasonable to do this in 44 hours or less by commercial flights; one sample itinerary I found was (all times local):

• Leave London Heathrow at 12:30 PM, Thurs. Sept. 28; arrive Bangkok at 6:05 AM, Friday. (Thai Airways, Flt 911)
• Leave Bangkok at 7:30 AM Friday, arrive Tokyo Narita at 3:40 PM Friday. (All Nippon, Flt 5696)
• Leave Narita at 4:55 PM Friday, cross date line, arrive LAX 10:52 AM Friday. (All Nippon, Flt 7018)
• Leave LAX at 1:08 PM Friday, arrive back in Heathrow at 7:40 AM Saturday. (United, Flt 948)

You'd be arriving 43 hours, 10 minutes after you left; you'd have spent 38h, 14m on aircraft, and the trip would cost $5459 economy. And your luggage would wind up in Cleveland. Interestingly, the LHR-NRT-LAX-LHR itinerary, without the Bangkok stop, takes less time in the air (31 hours) but due to the connections, takes longer total. (And is $1000 more, not that that really matters.) --ByeByeBaby 19:25, 10 September 2006 (UTC)

September 9

Sandalwood characteristics

I am a hobbyist and would like to make a gavel out of sandalwood for presentation to a friend but I do not know if Sandalwood can stand knocking especially in a cold country. I have searched through the various relevant topics in Wikipedia as well as on the Internet, without success. Would appreciate some advice on this or some links from which I can obtain such information. Thank you. 218.186.8.12 01:54, 9 September 2006 (UTC)Kenneth Ang

Will your friend be using his gavel outdoors in the winter? In India, the government owns all Sandalwood trees, you'll have to deal with their infinite beaurocracatagcauauaucy to get your wood. Or, you could probably bribe someone.....

The friend in North America will be using the gavel during Lodge Meetings. Anyway if I have to go through endless beaurocracy just to get a piece of wood big enough to make a gavel, I'd rather not. All the same, it will be interesting to find out if Sandalwood will crack or split with constant knocking, as with gavels.

Mechanism of thermoception

What is the mechanism in which thermoception occurs? I remember it being "rapid coagulation of certain enzymes," to quote Dean Edell perhaps incorrectly or in the wrong context from my memory of two years ago. — [Mac Davis] (talk) (Desk|Help me improve)

That isn't really an accurate description. Research into mammalian thermosensation has advanced quite rapidly recently. Briefly, ion channels of the transient receptor potential (TRP) family, are found in the nerve endings of primary afferent fibers. When activated by a ligand that we perceive as hot (such as capsaicin) or cold (such as menthol) the channel opens and allows an influx of ions. This, in turn, causes an action potential which we interpret as "hot" or "cold". These same receptors appear to mediate the response to temperature itself also (as opposed to chemicals we perceive as hot or cold), though the exact mechanism of channel activation is currently unknown. TRP channels exhibit distinct thermal activation thresholds in mammals (>52 degrees C for TRPV2, >approximately 34-38 degrees C for TRPV3, >approximately 27-35 degrees C for TRPV4, <approximately 25-28 degrees C for TRPM8 and <17 degrees C for TRPA1). You can read more about this in the scholarly literature [16] [17] Rockpocket 06:04, 9 September 2006 (UTC)

The full text of Sven-Eric Jordt, David D McKemy and David Julius. Lessons from peppers and peppermint: the molecular logic of thermosensation Current Opinion in Neurobiology 2003, 13:487–492 is available on the net, and is a worthwhile review as a basis. Enzymes do not seem to be involved, nor any coagulation - in the ordinary "permanent" sense - unless the term "coagulation" was used rather unconventionally as a word to convey the idea of a (reversible) structural change in a protein. In that sense, temperature-related perturbation in protein structure, as opposed to chemical receptor interactions, may well be the basis for the ion channel changes, but details are lacking. Interestingly, we seem to have about 30 "coldness" nerves for every "warmth" nerve - why? --Seejyb 06:43, 9 September 2006 (UTC)

Dangerous Combination?

Hi, I would like to know please, if the Medications listed below, taken as a daily Regiment (45 Yr. Old Female) Pose any potential interactions, and or health risks? Any Feedback will be Greatly Appreciated. Thank You For Your Time And Concern.

Sincerely,
MmHm

• TEMAZEPAM
• TRAZADONE
• RITALIN
• LEXAPRO

• This is the kind of thing you should ask a doctor as indicated at the top of this page. - Mgm|^(talk) 09:00, 9 September 2006 (UTC)

A pharmacist could also answer your question over the phone. BenC7 09:16, 9 September 2006 (UTC)

Well, they are all different classes of medications and it would probably depend on the doses and underlying illness. Certainly, any one of them could have serious side effects depending on how they are used and the individual taking them. If the Lexapro is taken for depression, the trazodone for sleep, the temazepam for anxiety, and the Ritalin for ADHD, and a person has all four problems, then it seems reasonable. However, one problem might occur if the Ritalin is being used to make a person more awake during the day while the trazodone is being used at the same time for sleep, then there are probably better ways to get this benefit. As you must understand, it's simply not possible for anyone here to know enough about the clinical situation you are involved in to competently give you an answer. In the end, the prescribing doctor(s) are your best source of information. InvictaHOG 10:10, 9 September 2006 (UTC)

As always, it's always best to consult with your physician, because all drug interactions must always be considered in the context of the individual patients' health profile. However, there is an online source for checking documented drug interactions-- use at your own risk: Check Interactions - DrugDigest--Mark Bornfeld DDS 13:32, 9 September 2006 (UTC)

Physics problem - not homework

I must be doing something wrong working out this problem:

A 1200kg car goes around a corner banked at an angle of 14° travelling at 80km/h. Is a friction force needed to keep the car on the road? If so, how much?

I am using the equations (tan θ = v²/rg and F_centripetal=mv²/r). Is there enough information in the question? BenC7 09:14, 9 September 2006 (UTC)

I would think the radius of the turn would also be needed, unless it cancels out in the calculations. StuRat 10:57, 9 September 2006 (UTC)

Assume a radius of 20m, another one of 200m, do the calcs, and if they aren't the same the problem is the problem, which it seems to be. --Seejyb 12:58, 9 September 2006 (UTC)

Our practical experience makes us worry that the car might go off the road to the outside of the corner. But in the artificial situation of no friction, the car could also slide off the road to the inside of the corner. Consider both possibilities. --Gerry Ashton 13:41, 9 September 2006 (UTC)

If you assume an infinite radius, the answer is yes, because the car would eventually slide down off the ramp. If you assume a very small radius, the answer is again yes, because the car would then immediately slide off the top edge. There needs to be a very specific radius for this question to make sense. I think? Maybe I'm being physically naive.  freshofftheufoΓΛĿЌ  15:25, 9 September 2006 (UTC)

To further explain my point: Since the answer is "yes" in both extreme situations, let's calculate the friction. Since a ramp with an infinite radius doesn't exert any force on a car that a straight ramp wouldn't, the amount of friction needed to keep it from sliding down is equal to the amount needed when the car is on the slope at stand-still. In case of a small radius, the only thing that you can calculate is that the amount of friction needed approaches infinity. The only other case to consider is the one where friction isn't required.  freshofftheufoΓΛĿЌ  15:31, 9 September 2006 (UTC)

Whether the track is banked or not, you still need the radius of the curve that the car is following.--Light current 21:15, 9 September 2006 (UTC)

Yes, but in that case, the answer is "yes" if the speed is over zero for every radius less than infinity.  freshofftheufoΓΛĿЌ  08:13, 10 September 2006 (UTC)

Although there is not enough information to say that the frictional force is x Newtons - we can work out a relationship showing how the frictional force varies as we change the radius of curvature. Use r = v² / (g tan θ) to work out the limiting case where no friction applies - i.e. that the normal reaction force from the road surface is sufficient to both balance the object's weight, and accelerate the object with centripetal acceleration of v²/r. For θ = 14º, g = 9.81 m/s², v = 22.22 m/s; r ~ 202 m. Lower than 202m and the object needs friction pointing up the slope, greater than 202m and the object needs friction pointing down the slope. By very rough back-of-the-envelope calcs (and I might have made a mistake), I think the frictional force is; F ~ 2848 - 575000/r F is in Newtons - and the positive direction is up the slope, r is in metres. Note that this is pretty approximate, and it's more accurate if you keep the thetas, m's, v's g's in the equation, rather than multiplying and simplifying as I've done. Note also, that if F = 0, the above equation gives r = 202m, as I had before.Richard B 21:10, 10 September 2006 (UTC)

cholesterol reducing spreads.

Hi, is it better to eat a cholesterol reducing spread (such as benecol) to lower your cholesterol level, or does the actual eating eating of the spread supply you with more cholesterol anyway so you are only reducing the cholesterol from the spread?

There are two cholesterol goals, keeping bad cholesterol low and good cholesterol high. Avoiding all cholesterol only handles the first part, while a product like Benecol has the potential to do both. StuRat 10:43, 9 September 2006 (UTC)

Flash cubes

Back when instant compact cameras were a novelty (mid-70s) some flash cube types required no battery but the camera was just shorting two leads connected to the respective cube face lamp. The lamps (behind the cube faces) contained a metal wool that ignited upon shorting the respective wires and produced the flash. I never understood the principle involved in igniting a ball of metal wool by shorting the wires leading into it. Anyone know?

I believe the "wool" was a flammable magnesium alloy which, when heated by the electrical current (like a filament), rapidly burned in the presence of oxygen from the air. This puts out a bright, but short-lived, flash of light. See flash (photography). StuRat 11:50, 9 September 2006 (UTC)

Is it possible that the battery was built into the film pack, so some people might not have noticed that the camera was equipped with a battery? --Gerry Ashton 13:43, 9 September 2006 (UTC)

There are a couple of related questions here; I'll take a stab at them.

First, it's actually remarkably easy to burn many metals under the right circumstances. A lot of metals are just waiting for a bit of activation energy so that they can oxidize. A nine-volt battery will easily and very rapidly heat a bit of wire from steel wool or a narrow strip of aluminum foil to incandescence and melting or oxidation. (Do be very careful if you try this one at home; small drops of molten metal are, obviously, dangerous.) Flash cubes contain lengths of very, very fine metal wire (typically some combination of the reactive metals magnesium and aluminum). When an electric current is supplied to the ends of the wire, it heats very rapidly due to its electrical resistance, to the point where the metal burns in a bright flash of light.

Conventional flash cubes, then, relied on a battery in the camera to supply that small spark of current that heated the wire in the cube to ignition. In the early 70s, battery-less flash cubes were introduced. Called Magicubes or X-Cubes, they relied on a piezoelectric crystal for their operation. When the flash was triggered, a tiny spring inside the flash was released mechanically; this spring drove a pin into a piezoelectric crystal, generating a pulse of current sufficient to ignite the flash. (It's very similar to the 'pushbutton' starters on modern gas barbecues.) These new contactless flash cubes were employed on cameras like the Kodak Pocket Instamatic 60; that linked web site has pictures of the cubes and an explanation of their function (scroll down).

I don't know of any flash cubes that were operated just by shorting the pins on the base of the cube; I agree with the original poster that such a setup seems unlikely to work (unless the flash cube contained an integral battery—something I've not heard of). The Magicubes had a mechanical trip (a little plunger extended up from the camera body into the cube to fire the flash) and lacked any electrical contacts. TenOfAllTrades(talk) 14:51, 9 September 2006 (UTC)

I've always wondered about that. I once bumped into someone in the dark (at a surprise party) causing a flash cube to fall to the floor and go off. Never knew how that was possible. Rmhermen 23:19, 9 September 2006 (UTC)

clicking rat

Hi, I have a small albino rat, about 7 weeks old. She seems to be quite healthy (I think) aside from the fact that she exhibits a nearly continuous "clicking" sound. At first, I thought it mighth just be tooth-clicking, which I've read is a sign of contentment in rats, but nowadays she does it almost all the time, with a frequency of around 1 Hz. I'm no longer sure the sound is coming from her teeth - it almost seems like it's correlated with her breathing. She is taking some antibiotics for another issue earlier on that seems to have cleared up (she was sneezing a lot - but she doesn't any more). Any ideas? Feel free to forgo suggestions that I go and take her to the vet. I probably will anyways - just wondering if anyone has any advice or experience in the matter. Thanks! -bmk

I had a hamster probably 10 years ago that seemed to do the same thing, though not all the time. I assumed it was tooth-clicking.  freshofftheufoΓΛĿЌ  15:20, 9 September 2006 (UTC)

SI unit

Why people created SI unit ??

In short, to standardize scientific calculations. For more information see International System of Units, especially the history section. - Dammit 14:50, 9 September 2006 (UTC)

Originally, during the French Revolution, a new, rational, system of measurement was created to unify measures in France. (France previously had many provincial systems.) Then it became popular for calculations. Peter Grey 01:17, 10 September 2006 (UTC)

It's much simpler. For a further elaboration, see my standardised answer on my user page. DirkvdM 08:10, 10 September 2006 (UTC)

Is it possible to see the change history of a definition

Is it possible to see the change history of a definition — Preceding unsigned comment added by 64.142.81.252 (talk • contribs)

What do you mean by 'definition' Do you mean the lede para?--Light current 17:52, 9 September 2006 (UTC)

Or do you mean etymology? If so, you need an etymological dictionary.--Shantavira 19:21, 9 September 2006 (UTC)

Or do you mean the history of a Wikipedia article? Just click the 'history' tab at the top. DirkvdM 08:33, 10 September 2006 (UTC)

This is a language question. What you're talking about is semantic change. A word's changing definition is generally only observable when it's documented. In comparative studies, it is possible to see a change in meaning of different morphemes. The English word black is cognate with the Russian word for white. AEuSoes1 08:38, 10 September 2006 (UTC)

Copper tubing

And other large bore metal tubing. How is it made?--Light current 17:51, 9 September 2006 (UTC)

Some are extruded... a slug of metal is pushed through a die, which forms it into a circular shape. To make a hollow pipe, the die is in the shape of a hole with approximately the outer diameter of the pipe, and the die has a solid center with approximately the inner diameter of the pipe. And yes, if you're wondering what holds the center of the die in place, it is connected to the outer part of the die via a 'fin' of sorts. The metal being extruded through the die splits to pass around that fin, then re-joins and cold-welds together, making a hollow tube. Have a look at the article on Extrusion. 192.168.1.1 20:24, 9 September 2006 (Huh?)

THanks. I was wondering about the central part. I have heard stories about 'floating' internal dies as well. Also its this rejoining that I dont understand. For instance how does it work. THere are'ent any seams visible on the finished pipes!. How come?--Light current 21:54, 9 September 2006 (UTC)

If enough pressure is put on metal, is will cold weld to other metal. See the link for an explanation. StuRat 00:25, 10 September 2006 (UTC)

Also, some large diameter thin tubing may be formed as a long, flat sheet, which is then bent to form a tube, and welded at the seam. This method can be used for heating ducts, for example (although many of those are rectangular). StuRat 00:25, 10 September 2006 (UTC)

Why would I want to heat ducks? Oh ducts! 8-). Sorry straight face 8-|--Light current 00:31, 10 September 2006 (UTC)

Some people do prefer a nice Cold Duck. :-) StuRat 03:21, 10 September 2006 (UTC)

I need to see how the m/c works really. Must visit a pipe factory.--Light current 00:40, 10 September 2006 (UTC)

If you do, make a schematic and add it to the extrusion article. I also have difficulty visualising this. DirkvdM 08:37, 10 September 2006 (UTC)

West Nile Virus

is it a good strategy to infect myself with West Nile Virus now when I'm healthy and won't have anything more than a mild flu/cold from it? Then,I'll be immune FOREVERE! !! Jasbutal 20:31, 9 September 2006 (UTC)

Except for the part where you might die. No, it is not a good strategy. The best one would be to never contract West Nile fever. This way, you completely avoid the anorexia, nausea, vomiting, eye pain, headache, myalgia, diarrhea, rash, lymphadenopathy, and possibly, if it passes the blood-brain barrier, encephalitis, and spinal meningitis. Just not getting sick at all is the best "cure!" — [Mac Davis] (talk) (Desk|Help me improve)

what are you talking about!? No one between the ages of 20-60 years old dies of west nile unless they have a compromised immune system. The old and the young are the ones who die, with everyone else, you can barely even notice the symptoms. Jasbutal 20:55, 9 September 2006 (UTC)

The chances of you getting West Nile Virus are slim (depending on where you live), and I would take Mac Davis's advice and try not to get infected at all. And I don't think it's possible to get West Nile Virus on purpose...(?) —EdGl 00:08, 10 September 2006 (UTC)

There may be a low probability of dying from West Nile Disease if you are a healthy adult, but not a zero probability. So, it's a bad plan. StuRat 00:19, 10 September 2006 (UTC)

false. It's a bad plan if the probability of me dying later on in life from this virus doesn't outweigh the probability of me dying from it right now. Jasbutal 04:56, 10 September 2006 (UTC)

Ok, if you want to get into it further, you also have to assign a value to the intervening years, between dying now and when you are old with an impaired immune system. Also, there's a rather substantial probability that a cure will have been found before that happens. StuRat 09:54, 10 September 2006 (UTC)

Let's take an exaggerated example: you are currently 20 years old. If you voluntarily catch WNV now, you have a 40% chance of dying. If you don't, then you have a 50% chance of catching it involuntarily on your 60th birthday with a certainty of immediate death. Should you pass your 60th birthday, you will live until 80. What will you do? Of course, my figures are ridiculous, so feel free to come up with more accurate ones.-gadfium 05:56, 10 September 2006 (UTC)

Are you actually asking a question, or are you trying to educate RD?  freshofftheufoΓΛĿЌ  08:08, 10 September 2006 (UTC)

So I suppose the people who recommend against Jasbutal's vaccination idea also oppose the vaccination against small pox and other deadly diseases. After all, such vaccinations carry with them a small chance of dying. AEuSoes1 08:21, 10 September 2006 (UTC)

• You forget that the chance of dying from a vaccination is much lower than dying from the West Nile virus if you contract it. If I had to choose, I'd prefer the vaccin. - 87.209.70.231 14:12, 10 September 2006 (UTC)

heating my house

where can I find the prices of a btu of electricity vs a btu of natural gas (for whatever state)?

I want to do an analysis to see if it's cheaper to buy some space heaters and cut my gas service for this winter. Jasbutal 20:39, 9 September 2006 (UTC)

The prices vary from provider to provider, and since you don't seem to want to disclose a specific state, all we can do is estimate. Natural gas prices are certainly rising, and with the winter coming, heating costs are becoming more and more apparent. I'll do what I can to find some numbers for you, or maybe someone else might be able to answer first. --Russoc4 21:02, 9 September 2006 (UTC)

I should also add that forced air heaters and space heaters have different efficiencies when it comes to filling a house with heat. Space heaters are localized and are only intended for one room in use. Forced air heaters (usually) maintain the temperature in an entire house. --Russoc4 21:07, 9 September 2006 (UTC)

yea, I just wanted an approximation. I've got numbers now , just have to compute them: Jasbutal 21:12, 9 September 2006 (UTC)

http://www.eia.doe.gov/cneaf/electricity/epa/epat7p4.html

http://tonto.eia.doe.gov/dnav/ng/ng_sum_lsum_dcu_nus_m.htm

It's not worth it, by a big factor of 1.75 too. Jasbutal 21:21, 9 September 2006 (UTC)

electricity : $0.09/kwatthr = $0.09/(1000 J/s * 3600 s/hr * 1hr) = $2.5 * 10 ^ -8 per Joule

natural gas : $14.92/1000 ft^3 * 1 ft^3/1000 btu * 1Btu/1054.35J = $1.4 * 10 ^ -8 per Joule

Well, good job at figuring it out before us. Do try to refrain from using obscenities though. --Russoc4 21:26, 9 September 2006 (UTC)

sorry, I forgot this was the science desk Jasbutal 21:29, 9 September 2006 (UTC)

I am a bit confused about the 'obscenities,' as well as the somewhat seriousness of the comment. — [Mac Davis] (talk) (Desk|Help me improve)

it's a lot more casual over in Muskallaneous. Jasbutal 23:26, 9 September 2006 (UTC)

While it's quite true that it's more expensive to heat an entire home with electricity than with natural gas, there is another option: only heat the portion of the house you are actually using. Of course, you do need to heat the entire house enough to prevent the pipes from freezing, and I recommend using gas for this. However, if you only heat your bedroom to a comfortable temp at night, with an electric space heater, that should save you a fair amount of money. The daytime is trickier, as you're likely to move from room to room. However, you don't need to provide much heat to storage rooms. For most families, I'd think an automatic thermostat that turns the temp down to 40 at night, and up to 65 in the day, with supplemental heat from electric space heaters, might be the least expensive way to heat the home. The temp should also be turned down to 40 when everybody leaves the house for work or school. StuRat 00:00, 10 September 2006 (UTC)

There are also some safety issues with space heaters:

1) Don't ever use kerosene space heaters, they should be banned.

2) Don't let children use electric space heaters, as they can start a fire if paper is touched to the elements.

3) Get electric space heaters with tilt and overheat sensors, which turn off under those conditions.

4) Don't ever use a space heater with a frayed cord or a cord that overheats.

5) Don't ever run the cord under carpet, as that will allow heat to build up.

6) Make sure any extension cords are rated to handle the space heater's wattage (typically 1500 watts).

7) Place space heaters far from any flammable materials, like blankets.

StuRat 00:12, 10 September 2006 (UTC)

...and wear a hat. But coming back to the original question, the price per unit of energy should be shown on your utility bills. In the UK it has to be there by law.--Shantavira 08:19, 10 September 2006 (UTC)

Rats wanting to be held

According to the article Pet rat, pet rats often (or, at least sometimes) position themselves near the cage doors, wanting to be held by their human owners. Is there really any scientific proof for this? Is it likely that rats actually want to be held? Could there not be another reason for their behaviour (e.g. wanting to escape)? The article also says that some rats enjoy riding through the house sitting on their owner's shoulder. Is this idea proven? Perhaps the rats position themselves on the shoulders, merely being too afraid climbing on the sweater? In general, common belief and this article says (assumes?) that rats enjoy (human) social interaction: my general question, thus, is if this really is true, or if it is merely a human wish. --Andreas Rejbrand 21:10, 9 September 2006 (UTC)

The phrase is "wanting to be held", not "wanting to be hold". StuRat 23:42, 9 September 2006 (UTC)

• I suspect you haven't spent any time with rats. They are very affectionate, they distinguish between different people, they seek out pleasure (like high viewpoints giving them free rides). Now, obviously, one cannot scientifically prove they "want" anything, since rat-mind-readers aren't any more available than human ones are, but they certainly express what appear to be preferences. --jpgordon^∇∆∇∆ 21:31, 9 September 2006 (UTC)

Well, actually, I have spent quite some with pet rats (http://english.rejbrand.se/rejbrand/djur.asp). But yet I cannot say I am sure about the hypotheses. --Andreas Rejbrand 22:12, 9 September 2006 (UTC)

It is near impossible to "prove" anything about animal behaviour. You could ask, how do we know dogs actually enjoy human interaction? How do we know that them retreiving a ball or a frisbee is enjoyable, and that there is not another reason for their behaviour? The answer is that, when given an opportunity, behaviour without an obvious inherent biological purpose that animals freely choose to do is what we define as behaviour they "enjoy", based on the premise that that is what humans do. Whether there is another function for such behaviour is open to interpretation, in the same way human behaviour is. Consider why people go to the gym, play sport, or even have sex for enjoyment. The answer is: because our body rewards our brain with positive inputs in reponse to these activities. And this is because it makes evolutionary sense to reward and encourage behaviour that is constructive to survival and discourage behaviour that isn't. So if you take "enjoyment" in that context, it is clear rats do enjoy human interaction, but the reason for that is open to speculation. Rockpocket 22:32, 9 September 2006 (UTC)

Wanting to be held is a mammalian/bird thing, as the young of pretty much every species desire contact. Many "pet" mammals and birds retain this characteristic into adulthood. While this is mainly true of social species, some not-social species, like cats, also retain this characteristic. StuRat 23:47, 9 September 2006 (UTC)

Do you ever sit at your cage door, wanting to be held? (Someone had to ask.) DirkvdM 08:44, 10 September 2006 (UTC)

In my case, I really am just trying to escape. :-) StuRat 09:49, 10 September 2006 (UTC)

Similar questions could be asked about humans. Do they really want to go throught the same routine everyday (even every holiday for some)? Or do they just not know any better? DirkvdM 08:44, 10 September 2006 (UTC)

Let me rephrase my question slightly: does a rat sitting on a shoulder feel pleasure (as the article claims) or fear (e.g. of falling down)? Does a rat sitting near the cage door want to be held by a human, or does it want to escape? --Andreas Rejbrand 10:54, 10 September 2006 (UTC)

My reason for asking is merely that I want the best for my rats, combined with a bit of scientific interest. --Andreas Rejbrand 10:55, 10 September 2006 (UTC)

What they want might not be what's best for them. Suppose they want to escape. Would they be able to survive? They might have to compete with other (wild) rats and domesticated rats wouldn't stand a chance. If you want what is best for domesticated rats maybe you should not have bought them (if that's what you did), thus creating a demand for the breeding of more domesticated rats. Assuming they don't want to be kept in captivity, that is. But maybe they don't mind at all, if they don't know otherwise. That is actually quite probable. There is still the natural drive that all animals have. Look at how wild rats live and try to create circumstances that gives your rats an opportunity to live such a life. DirkvdM 13:33, 10 September 2006 (UTC)

True, indeed. Yet my original question has not been answered. In fact, I believe no human really know the answer. But the authors of the Fancy rat page must have learned these "facts" somewhere. --Andreas Rejbrand 16:27, 10 September 2006 (UTC)

I refer you to my answer above, it depends on how you define "pleasure". Most definitions are subjective in terms of animal behaviour ("gratification", "satisfation", "enjoyment") However, one definition is "one's will, desire, or choice". If the rats freely choose to ride on your shoulder - it is their choice - then we could say they make "make known their pleasure". Strictly we should no use terms such as these in describing animals, its a type of anthropomorphism. However, if we take our definitions of enjoyment/pleasure as i described above, then its not so innapropriate. Rockpocket 20:22, 10 September 2006 (UTC)

LED usage

Why did it take so long for LEDs to be used in traffic lights, road signs and for vehicle lights?--Light current 22:39, 9 September 2006 (UTC)

There must have been some change in the technology, as they now seem to be much brighter than they originally were. StuRat 23:30, 9 September 2006 (UTC)

Hi briteness LEDs have been available for some time (>10yrs) but its only recently I ve started seeing them used in these apps. Could it be to do with the cost?--Light current 00:08, 10 September 2006 (UTC)

Yes. Until recently, LED's in the specific colors required for traffic signals were extremely expensive. Both the reduction in manufacturing cost, and also the increase in utility (electric) costs have made LED signal faces very cost effective. Early LED's did not have the proper yellow and green colors to conform to the ITE standards. Also, a typical incandescent traffic light bulb is 160 watts. An LED face draws from 10 to 25 watts, making the return on investment much better. 192.168.1.1 01:01 10 September 2006 (UTC)

Whats ITE?--Light current 05:24, 10 September 2006 (UTC)

Suppose (a very rough estimate) that on average every 100 household neighbourhood has one intersection with 10 lights (four or more for the cars, same for pedestians and possbly some for cyclists). Suppose a saving of 100 W per light. That's 10 W per household. 24/7. A typical lightbulb comsumes 50W, about 20% of the time (at night). So it is an energy saving equivalent to one less lightbulb per house. Nothing big, but not bad either. DirkvdM 09:01, 10 September 2006 (UTC)

Lightcurrent: Sorry, I should have put that in. ITE = Institute of Transportation Engineers. www.ite.org

DirkvdM: Actually for the agency paying the bills, it is a huge savings. Given a typical intersection with three vehicle heads on each mast arm, for a total of 12 heads, and eight more pedestrian heads, there will always be 20 faces lit at any time. Traffic signals operate 24 hours a day. The energy savings is a pretty big deal, 160W x 20 versus 15W x 20. We're paying around ten cents per KWHour (if I recall correctly), and we've just slashed our operating cost to around a tenth of what it was with incandescent bulbs. Then there's the labor savings. Incandescent bulbs were regularly replaced in a formal re-lamping program. The LED faces will last for up to ten years without requiring re-lamping at all. My agency operates around eighty signals, so for us the decision to upgrade to LED's makes economic sense. --192.168.1.1 17:23 11 September 2006 (UTC)

Ah yes, any labour savings usually make a huge impact. But for the electricity cost my story wasn't all that different, except that I approached it from a differnt angle, not the total cost (for what area?) but the cost per household, which scales better (just multiplky by the numebr of households). Also you're talking about much bigger intersections, of which there aren't that many. So they sound inpressive but the more ubiquitous smaller intersections make a bigger diiference. That is a common mistake, to focus on the big things, but life consists more of the l;ittel things. Take the New York WTC attack. That made people fear terrorism, because thousands died. But because it was pretty much a one-off thing it's peanuts. Cars kill as many people in the US every few months. Every few months. And that's just the US. Worldwide the deathtoll is about half a million people per year. That is what people should fear, not terrorism. A common mistake, but a costly one. DirkvdM 17:34, 10 September 2006 (UTC)

Eye burns

How quickly do frostbite/heat burns dissipate when on the eye? Can you lose parts of it if you aren't careful? — [Mac Davis] (talk) (Desk|Help me improve)

Can you get frostbite in the eyes? maybe, if you splash cryogenic liquid in. [18]--Light current 00:42, 10 September 2006 (UTC)

In Antarctica, as well as other places, it is so cold and dry I bet you can. I was thinking of LN2 actually. — [Mac Davis] (talk) (Desk|Help me improve)

I dont remember hearing of any of the Antarctic explorers getting frostbite in the eyes. Other parts of the body - yes. THe simple answer is to wear protective goggles when you pour it.--Light current 01:22, 10 September 2006 (UTC)

The skin around the eyes can certainly get frostbitten, but under extremely cold conditions your eyes will water profusely as a way (I must assume) to keep them from getting too cold and freezing over.  freshofftheufoΓΛĿЌ  08:03, 10 September 2006 (UTC)

The brain is always maintained at operating temperature, irrespective of how cold it is, because else you'd die. Maybe the eyes are so importatnt that they get the same treatment. Just a guess. DirkvdM 09:11, 10 September 2006 (UTC)

I suppose you could get a frostbitten eye by pouring liquid nitrogen on one. My suggestion: don't do that. Similar comment for putting a cigarette out in your eye, I suggest an ashtray, instead. StuRat 09:44, 10 September 2006 (UTC)

I must admit that what you say does sometimes make a lot of sense. DirkvdM 13:35, 10 September 2006 (UTC)

EMP's

why should I be worried about http://en.wikipedia.org/wiki/Electromagnetic_pulse ??

My PC is in a faraday cage, as is almost all important electronic equipment. right? Jasbutal 23:25, 9 September 2006 (UTC)

Well, an EMP could signify that a nuclear device has been detonated in the area, news of which... would probably worry me, I don't know about you though... --Mnemeson 23:29, 9 September 2006 (UTC)

You really don't need to worry about it, who told you that? — [Mac Davis] (talk) (Desk|Help me improve)

What about the wires into your PC-- are they filtered well enough to stand EMP?--Light current 00:09, 10 September 2006 (UTC)

you do all realize that if you bank with a modern corporation, your account is just a file on a computer...right? I'm not worried about money, or people, or nukes, or whatever, i'm worried about my dang money. Jasbutal 04:54, 10 September 2006 (UTC)

A communist's wet dream, an idea used in several films - wipe all banks clean and mankind will start with a clean slate. Any new money will have to be distributed evenly if there is no way anyone can prove how much money they had. I wonder if the same principle applies to companies and even nations. Of course rich countries have more and better production facilities and other physical goodies, so they can easily assume the top dog position again, but any differences in virtual property (money) will have disappeared. Right? Also, suppose not just money, but proof of ownership of a factory is deleted? Would that be possible and how migh ownership be distributed then? DirkvdM 09:19, 10 September 2006 (UTC)

you're scaring me dirk!! What can be done about the EMP threat!? back up everything on notarized papers? Jasbutal 18:25, 10 September 2006 (UTC)

That actually happened in the Soviet Union back in the 70s, I think it was. They massively revalued the ruble and introduced a new series of banknotes. People had to line up to exchange the old ones for the new ones, but they had to be able to explain how they had come by the old ones legitimately, otherwise they couldn't get the new ones, and the old ones became useless after a short while. Tough titties for a lot of people. JackofOz 21:04, 10 September 2006 (UTC)

September 10

Insect Costa Rica

• 
  unknown Insect, Costa Rica, Tapanti National Parc
• 
  unknown Insect, Costa Rica, Tapanti National Parc

These photos were taken at Costa Rica in march. It seems, one is male, the other female. On my mind, it's not a Parascopioricus. Does anyone know the name? --Ruestz 00:33, 10 September 2006 (UTC)

Phasmatodea? Great pictures by the way, we'll have to add them when we know for sure. — [Mac Davis] (talk) (Desk|Help me improve)

The LucidCentral Guide to Insect Orders is a useful tool for identifying insects to the order level. Unfortunately it doesn't go more specific than that. BenC7 01:32, 10 September 2006 (UTC)

What do snake eggs look like?

I found a partially burried pile of soft, white, oval shaped things on the ground in my yard a few days ago. The "shell" came off easily revealing a dry, yellow, oval shaped thing. Someone told me they were mushrooms but I doubted that. If they are snake eggs, is there any way to find out what kind? I live in North Carolina(eastern US) if it helps. --Isamil 00:47, 10 September 2006 (UTC)

Not a very specific answer I know, but: Some animals, including some snakes, have eggs with leathery or other not-so-hard materials for the shell, so snake eggs is a reasonable first guess. Peter Grey 01:11, 10 September 2006 (UTC)

More generally, reptile eggs are soft, so they could be turtle eggs or from some other reptile. StuRat 03:08, 10 September 2006 (UTC)

A Button mushroom could be mistaken for an egg. 1001001 04:01, 10 September 2006 (UTC)

Wouldn't a mushroom have a 'stem' and an egg not? Also, opening it should make it very clear, or don't you want to do that (or even pick it up)? DirkvdM 09:27, 10 September 2006 (UTC)

Don't open them, they could be endangered. If you really want to know, you could wait 'till it hatches (that would take a lot of waiting around though). I agree with people here though, it is probably a reptile of some sort. Were they in a hole or resting on the ground? Turtles and lizards generally create a hole or burrow for their eggs. --liquidGhoul 11:49, 10 September 2006 (UTC)

I can't remember ever seeing a turtle in this area. They were partially burried in mulch and were not in a hole. Tomarrow, I'l see if I can take a picture of them. --Isamil 23:25, 10 September 2006 (UTC)

Salty Fish

Since lots of edible fish live in saltwater, why do the fish themselves not taste salty?--Light current 00:57, 10 September 2006 (UTC)

They don't? I think most of them taste salty to me. Anyway, the fish has a constantly active salt-getting-out system, because it would die if it had too much salt. — [Mac Davis] (talk) (Desk|Help me improve)

Though at the same time, the salt levels in their body are much higher than freshwater fish, which is why they die if put directly into freshwater.  freshofftheufoΓΛĿЌ  07:58, 10 September 2006 (UTC)

... because the inside and outside wouldn't be isotonic. The salty fish would absorb too much water and 'blow up'. Conversely, a sweet water fish in fresh water would shrivel. Few fish manage to migrate from one environment to the other, like salmon. I don't know how they do that, though, and the artiocle doesn't seem to say either (just skimmed through it). DirkvdM 09:31, 10 September 2006 (UTC)

So when these fish blow up, do we then call them bloaters?--Light current 10:25, 10 September 2006 (UTC)

How do I tell the difference between male and female gulls?

Anyone know? They all look the same to me. --84.65.209.240 01:11, 10 September 2006 (UTC)

Which particular sort of gull did you have in mind?--Light current 03:26, 10 September 2006 (UTC)

Bouys versus gulls?Edison 04:55, 10 September 2006 (UTC)

Some birds are very difficult to tell apart externally, though I'd bet in gulls there's some very specific (though relatively small) difference, e.g. beak color, color pattern, body frame. In order to tell the difference in cases where external inspection isn't reliable, blood or tissue samples may be required.  freshofftheufoΓΛĿЌ  07:56, 10 September 2006 (UTC)

More to the point, how do gulls themselves tell the difference?--Shantavira 08:30, 10 September 2006 (UTC)

Maybe they don't and just give it a try. Getting it right half the time should be sufficient to keep the species alive. Of course this would also mean that male gulls get butfucked a lot, but hey, if that's their thing. Some humans even like it. (Sorry about being such an open minded Dutchman again. :) ) DirkvdM 09:37, 10 September 2006 (UTC)

I'm no scientist but I'm guessing that the gulls themselves know their own sex... :) --Kurt Shaped Box 11:21, 10 September 2006 (UTC)

Female Gull

Male Gul

They look rather distinct to me. :-) StuRat 09:33, 10 September 2006 (UTC)

So they're distinguishable by the number of l's in their names? DirkvdM 09:41, 10 September 2006 (UTC)

What if they can't spel? DirkvdM 13:37, 10 September 2006 (UTC)

User:Freshgavin is correct - if you watch a breeding pair of gulls (herring gulls and GBB gulls at least) stood next to each other, 9 times out of 10, the male will be longer, wider and with a slightly bigger beak. It is very hard to tell sometimes though, unless you spend a lot of time watching them - and completely impossible when there's a big flock milling around. --Kurt Shaped Box 11:21, 10 September 2006 (UTC)

SPSS graph

Is it possible to do a histogram or bar chart with SPSS for a grouped frequency distribution table? -- Hersheysextra 01:35, 10 September 2006 (UTC)

Songs that break music theory rules

I was having a debate with my friend. He claims that music is a science, and that every song that sounds good in the world, follows the rules of musical theory. ie, every note is in the right key. Evry note is in perfect pitch. Now, I can't imagine that out of all the millions of songs in the world, there isn't at least one, that breaks at least one of these rules, while still being considered by at least some people, to be a good song. So, my request is, does anyone know any song like this? Personally, I have no knowledge of musical theory, but I do listen to a lot of music, and I think, music, like any art form, is subjective.--Richy 02:20, 10 September 2006 (UTC)

Depending on what era of music you live in, there are different rules. Depending on the culture you have different tastes. In the Far East, they like pentatonal systems, in the Middle Ages, Western harmony featured the perfect intervals of a fourth, a fifth, and an octave, and the rest were called "imperfect." Western tradition focuses on harmony and counterpointing, and in recent years we have grown to place attention on the melody of the song over whatever beat or chords might be playing in the "background." Think of a favorite rock song—you can probably remember the tune, but not necessarily followed the drummer's skills the whole song. — [Mac Davis] (talk) (Desk|Help me improve)

There are not very many music theory rules, and in fact the best music is often that which artfully bends the rules. Music that follows the 'rules' can be good, for instance some of the best rock and roll is perfect 4/4 time and uses only two or three chords. But some of the best pop songs go 'out of key' and time; Peter Gabriel's Solsbury Hill and Pink Floyd's Money (song) are both in 7/8 time; Michelle (song) by the Beatles, My Little Town by Paul Simon, and lots of other famous pop songs go 'out of key' (other than modulation, going up by a half-step for dramatic tension). He's not so well-known now, but perhaps the greatest songwriter of all time, Cole Porter, was very musically complex, going out of time and key all the time. And of course classical composers did it, Beethoven in the Presto movement of his Ninth Symphony, and all our favourite modern movie composers (the Imperial March, otherwise known as Darth Vader's theme, is a great example, as is a lot of Danny Elfman's stuff). Hope that helps. Also, another John Williams example is the Across the Stars love theme, which artfully changes key about 4 times. Anchoress 02:40, 10 September 2006 (UTC)

Who said 4/4 is better than, say, 6/8 (favorite of Elfman if I remember correctly), which is also "standard?" — [Mac Davis] (talk) (Desk|Help me improve)

I certainly didn't say that. But 5, 7, 11, etc are considered 'odd' times, unlike 2, 3, 4, 6, 8, etc. Anchoress 02:56, 10 September 2006 (UTC)

There are certainly conventions to music composition. They can and often are broken. Even the notes we define as notes (ie., what frequency we define a C to be, and so on) are not always followed, and not even in the Western oeuvre of music either. Dysprosia 07:54, 10 September 2006 (UTC)

About a century ago, some classical musicians decided that it was tome for 'out with the old an in with the new' because the rules were too strict (and indeed tehy were). But it was difficult to persuade composers to break with tradition, so they made new rules to replace the old ones. And some pretty stupid ones, leading to stuff like atonal music. I've heard some of it and it sounds like a pile of shite to me. DirkvdM 09:48, 10 September 2006 (UTC)

And those too were broken. Serial music has fallen somewhat out of fashion; focus these days seems to be on neotonality. Dysprosia 11:33, 10 September 2006 (UTC)

Not enough for there to be an article on it, though, it seems. DirkvdM 13:39, 10 September 2006 (UTC)

As Anchoress already said, good art bends the rules. More precisely, it finds the right balance between following and breaking them. What the right balance is depends on the audience (or the artist, really). Some people prefer simple easy listening music. An extreme example is muzak, which is more a utility than art. At the other exteme you find exprimental jazz or atonal music, which I already mentioned. (btw, in pop music there is a differnce across the Atlantic, with US music being 'easier' and European music more experimental.) But there must be some rules. Take rhythm. It's usually 4 or 3 based (or multiples thereof) and occasionally you get 5 (or, rather, take 5 :) ). 7/8 is already weird, so making that work in an easy sounding pop song (as in Pink Floyd's 'Money') is a sign of sheer class. Flamenco uses some unusual rhythms too, eg 12 beat, but not quite - 3-3-2-2-2 (one, two, three - one, two, three - one, two - one, two - one, two). Indian (improvised) music seems to have very relaxed rules. I once heard a player say that if during a concert two players end up playing the same rhythm, that is a happy coincidence. I have spent about a year composing music and I like to bend the rules. One little peice I called 'blues without a rhythm', which is exactly what it is. Then agian, there is a constant hint of a rhythm, but it keeps on losing it and then finding it again, or another rhythm. If there were no hint of a rhythm at all, it would be cacaphony. But following the rhythm too precisely kills the music, a crime committed by most classical performers.

MacDavis already mentioned that almost all intervals were considered bad in the middle ages. Such as the third. Hell, you can't even make a major chord without that. Let alone a minor chord. And Mozart did something revolutionary when he used a seventh in a peice. Nowadays music that doesn't use that all the time would be considered dull. i once heard that the worst interval is the diminished fifth. So I decided to base a piece of music on it. But prettty soon I discovered that it was really based on the fifth, with the diminished fifth being a variaton of that, one that created tension that had to be resolved. And that last bit is very important. The rules are something you fall back upon, but it's the temporary deviation that makes the music interresting.

I could go on about this for a very long time. Music is the best combination of science (math) and feeling there is. It makes the basic human thought paterns (intelligence) explicit more than anything I can think of. DirkvdM 11:29, 10 September 2006 (UTC)

Listen to 'The Black Angel's Death Song' by The Velvet Underground. :) --Kurt Shaped Box 16:58, 10 September 2006 (UTC)

A few months ago, on NPR, they talked about music theorist Dmitri Tymoczko, who recently wrote a paper describing a new type of geometry he had created to represent music. There have been all kinds of music geometries to represent music, but none of them got it "all" right, but his apparently does. His paper was accepted to Science magazine, the first music theory paper they had ever published in 120+ years. In that paper, he says that Chopin's piano prelude in E-minor (Opus 28, No. 4) is the make-or-break song. Apparently most predictors indicate that song should sound like crap, but it sounds fairly good. Raul654 17:06, 10 September 2006 (UTC)

Interior Plains of the United States

My 4th grader need to research information regarding interior plains in the United States. We were able to obtain information on the wiki under great plains. We are lookin for answers on specific questions such as:

1. What forces of nature cause the interior plains of the United States to be formed or in other words, how did it develop> 2. What is unique about the interior plains? 3. What efforts are being made to preserve the inerior plains?

My 4ht grader went to the library and they do not have any materials in plains under landforms. Please help her.

Thank you very much.

This is an encylopedia, and you can just type in "Interior Plains" in the Find box in the left. Push go, and you're there. :) — [Mac Davis] (talk) (Desk|Help me improve)

The Geologic Story of The Great Plains will help with 1 and 2. On 3, there are U.S. Grants available for Conservation of the Great Plains 1001001 04:12, 10 September 2006 (UTC)

irrigation engineering

what are the types of irrigation systems?

See our page on irrigation--Light current 05:04, 10 September 2006 (UTC)

dynamic hermaphroditism

Okay, there are sequential hermaphrodites that change sex as part of their life cycle, and simultaneous hermaphrodites that have both sex organs; but is there such an organism that dynamically changes its own sex based on current population sex ratio, environment, available resources, etc. ? Phoenix-forgotten 05:37, 10 September 2006 (UTC)

There are cases of evolutionarily 'unintended' hermaphroditism caused by environmental stress such as polybromated diphenylsin polar bears. But I doubt this is what you were looking for.---Sluzzelin 11:23, 10 September 2006 (UTC)

Sure. alteripse 11:29, 10 September 2006 (UTC)

Cell phone batteries

Is it true that if your current cell phone you use breaks and it is not repairible that the battery can be placed in another phone and all your data remains or is saved on the new phone.--Biggie 05:49, 10 September 2006 (UTC)

No, batteries have no capability of storing information in such a way. Even if there was a battery that was for some reason attatched to a memory chip, it would probably only work in the exact model of phone that it was constructed for.  freshofftheufoΓΛĿЌ  07:49, 10 September 2006 (UTC)

Battery, no. SIM card, yes, to some extent. Phones permit you to save data on the SIM card, which can easily be transferred. Dysprosia 07:54, 10 September 2006 (UTC)

Thanks for the info--Biggie 08:49, 10 September 2006 (UTC)

An amp's power consumption

Suppose I have a 100W amp. Does it draw 100W all the time? Or does that depend on how far I turn the volume up? Or even how loud the music is (the dynamics of the music)? I suppose the former but not the latter. If I set it at half the maximum volume, measured by subjective perception (it sounds half as loud). Is the power consumption then half of what it would be at maximum volume (so 50W). I'm pretty sure not (much less), but what is it then? DirkvdM 09:08, 10 September 2006 (UTC)

Yea, that's the maximum. Whether you reach the max would depend on both the volume of the recording and the volume setting on the amp. StuRat 09:13, 10 September 2006 (UTC)

If its class A, yes it will draw constant power wasting whatever doesnt go into the speaker. But if class AB (which has a max efficiency of 78.5%), then the power consumption is almost proportional to the power in the speakers (and hence the volume). In a class AB amp, there will be some constant power dissipation not related to the output power, but this will only be a few watts at most. See electronic amplifier--Light current 09:23, 10 September 2006 (UTC)

THe question of efficiency vs output power, Im not certain of.--Light current 09:43, 10 September 2006 (UTC)

In general electronic equipment may draw far more electricity than its rated output. High fidelity is a bigger goal with audio than efficiency. Any heat given off is the result of that inefficiency.Edison 19:29, 10 September 2006 (UTC)

gravitational waves and propulsion

Im aware that none of the machines that claim to produce these waves have been varified, but they exist right? What is the mainstream physics communities views on gravitational waves being used for propulsion or moving objects in the future? and are these the waves produced by gravitoelectromagnetism?

Robin

Well, gravitational radiation is produced whenever a mass accelerates, but for everyday masses and accelerations the waves are unobservably small. To produce enough gravitational radiation to detect, you need huge masses accelerating very fast, like binary neutron stars spiraling towards each other. (The reason they spiral towards each other instead of staying in a stable orbit is exactly because they emit gravitational radiation.) I did find a paper with the exciting title Gravitational radiation and its application to space travel, but it's all theoretical so far. —Keenan Pepper 16:18, 10 September 2006 (UTC)

We're out of transcluded pages

So, what happens now? Do we just delete old posts?--205.188.116.74 13:56, 10 September 2006 (UTC)

• Erm, I'm not sure I get what you mean. If you mean you can't transclude more templates than we have right now, we just archive the oldest day (it may even be done automatically), but I don't think we're out of transcluded pages. The max. limit was raised, and I doubt we hit it. - 87.209.70.231 14:05, 10 September 2006 (UTC)

Sexual Advice

Que: Can a curved penis be made straight with the help of surgery? — Preceding unsigned comment added by 59.144.180.72 (talk • contribs)

Probably, but we can't do that here on the desk. Take it to see a doctor.--Shantavira 16:43, 10 September 2006 (UTC)

I think so. Is it really worth the pain, hassle and expense though? Supposedly most men's cocks bend either to the right or left when erect. How 'curved' are we talking about? --Kurt Shaped Box 16:55, 10 September 2006 (UTC)

Apparently bent ones offer a better experience for the woman... obviously not to bent... but yeh, anyway, you may just be being to self conscious. Philc _T^E_C^I 17:26, 10 September 2006 (UTC)

• Penises are rarely straight; they don't need to be for good sex. I wouldn't worry about it. If you do, bring it up with your doctor. He's the only one who can decide if surgery can be done and if it is needed. - Mgm|^(talk) 19:46, 10 September 2006 (UTC)

if it's needed!? are you kidding me I'll get surgery if I damn well want it and can pay the money for it. Jasbutal 21:10, 10 September 2006 (UTC)

Youd be surprised, doctors do have the right to refuse to perform surgery you know, their not legally bound to straighten your penis on demand you know. Ususally you wont even know if they have refused, because they would have just had a few sessions with you, and chatted about what you want done, and by the end of it convinced you that you dont want surgery, because usually they're right. Philc _T^E_C^I 21:44, 10 September 2006 (UTC)

Curvature of space and time

What is the simplest way to understand the concept of space-time and its curvature?

the ? varible is part of the experiment that is affected by the independent varible.

 if you could help please. thank tou

Think of it in terms of a man's penis - supposedly most men's cocks bend either to the right or left when erect. I think space-time curves in the same manner. (sorry, that was a silly answer - but I couldn't resist) --Kurt Shaped Box 17:02, 10 September 2006 (UTC)

Well the ubiqutius explanation of general relativity is probably found at the article. It concerns a latex sheet representing the spacetime continum, and masses bend the sheet, curving it, and that is a gravitational field. — [Mac Davis] (talk) (Desk|Help me improve)

The rubber sheet is an reasonable simplification - as with most concepts of curvature in three (spatial) dimensions removing a dimension helps people to visualise it. As an undergraduate, one of my professors told me that to visualise the curvature in three dimensions is impossible. However, I find visualising a gravitating body as stretching spacetime by pulling it towards it (pulling more strongly nearer the body and less further away - inverse square law) makes for an acceptable visualisation. I justify this by imagining a triangle being stretched in just such a manner - the internal angles will equal less than 180% - demonstrating just such an hyperbolic geometry as is associated with a gravitating body.

Direct gene transfer using PEG and Calcium chloride

Sir/ Madam,

I will be benefitted if I get more information regarding and related to this subeject.

We don't seem to have an article on your meaning of PEG, and Calcium chloride has just a couple of sentences: "Aqueous Calcium Chloride is used in genetic transformation of cells by increasing the cell membrane permeability. This allows DNA fragments to enter the cell more readily." The reference isn't given. Melchoir 21:30, 10 September 2006 (UTC)

The PEG in this case is polyethylene glycol, linked from the dab page at PEG. What the original poster really needs here is either a good laboratory manual that describes the process in detail, or (ideally) a local colleague who has experience with transfections and can provide a protocol. TenOfAllTrades(talk) 21:45, 10 September 2006 (UTC)

Ah, I was thinking PEG would be a three-word name of a technique. Melchoir 21:47, 10 September 2006 (UTC)

Helium Balloon questions

1. What would a helium balloon do in gravity-less outer space?

2. What ratio of regular air to helium should go in a balloon so that it floats in the air stationary? Thanks! Reywas92 17:45, 10 September 2006 (UTC)

1. Unless it was quite strong, it would burst (without a bang).

2. It doesn't matter. Assuming it gets off the ground it will eventually reach an altitude at which its weight is balanced by its reduced lift in the rarefied air.--Shantavira 18:19, 10 September 2006 (UTC)

A helium balloon in space would inflate to the same size as on earth if the pressure differential were the same between the inside and outside. So if atmospheric pressure is 14.7 pounds per square inch or 101.325 kPa, and the balloon inflates to 1 foot diameter on earth, in space for it to inflate to 1 foot the internal pressure would have to be reduced by 14.7 PSI. Now consider temperature: if the balloon is in the shade, it will radiate off heat, become cool, and shrink. The pressure would decrease in proportion to the drop in absolute temperature, PV=nRT per the Gas laws. If the balloon is in the sun, it would heat up and expand. If it were in the International Space Station or the Space Shuttle, it would drift with air currents, with no particular tendency to rise to the ceiling or sink to the floor, since these surfaces would be interchangeable. If you untied the stem and let the helium spurt out, it would take off like a rocket, since Newton's Third Law says To every action (force applied) there is an equal but opposite reaction. The lack of a surrounding atmosphere for the balloon exhaust to "push against" would not invalidate this law. If you stuck a pin in it, it would burst, but silently,since there is no air to transmit sound. Echo 1 was a plastic mylar balloon put in space as a passive communication satellite in 1960 which lasted until 1968. 100 feet across, it was easily seen with the naked eye when in the right portion of the night sky to reflect sunlight. It can be seen at http://www.scienceandsociety.co.uk/results.asp?image=10300344&wwwflag=2&imagepos=1 No info on whether it was inflated with hydrogen or another gas, but a gas with larger molecules might not have diffused out through the skin as fast.Edison 19:53, 10 September 2006 (UTC)

It all depends on how big the ballon is, as its area (i.e. the weight of the skin of the balloon) goes up in squares, while the capacity cubes. So there is no one answer, though a formula could probably be concucted. Philc _T^E_C^I 21:52, 10 September 2006 (UTC)

Question about Sinusitis

I've had sinusitis before (eleven times in one year, at one point) and I'm fairly sure that it's not contagious, but I'd just like some verification, because this could be old information. Is sinusitis contagious, and if so, how contagious is it? Thanks in advance!! Srose (talk) 19:01, 10 September 2006 (UTC)

Contagiousness relates to spread of a disease from one person to another. Sinisitis can be infectious, but results mostly from bacteria already resident in the sinuses rather than "caught" from other people. You need to ask your physician what is causing you to have chronic sinusitis and what can be done about it. - Nunh-huh 19:16, 10 September 2006 (UTC)

Get your medical advice from a physician. 11 time in a year is way too much. See an Eye Ear Nose and Throat specialist. But from personal experience, there may be things he can do to alleviate the condition. Sinusitis can lead to some very bad things, such as meningitis.Edison 19:56, 10 September 2006 (UTC)

Thank you both very much! I've replied on your respective talk pages. I do get most of my advice from my physician and the specialists that I see, but of course they're unable to answer questions on a Sunday! :) Anyway, I'll repeat myself and say: thank you very much! Srose (talk) 22:20, 10 September 2006 (UTC)

What is insect hair largely composed of?

I know mammals have hair composed mostly of keratin. Many insects, like this moth, also have hair. Is it made of chitin, or some other substance? Gary 19:10, 10 September 2006 (UTC)

It's chitin. - Nunh-huh 19:12, 10 September 2006 (UTC)

How to tell if watermelons are ready to harvest?

I have this year learnt how to grow plants from seed. For fun I bought a packet of melon seeds and planted them in pots - I do not remember how long ago. I have three green melons about four or five inches in diameter.

How can I tell when I should harvest them please? As I am in the UK they may not grow as large as the watermelons for sale in supermarkets, as the latitude (or maybe I mean longitude?) here is about the same as Newfoundland and hence the sun is not as powerful.

As I noticed that something had eaten into the rind of one of them, I did cut that off the stalk and sliced it open and ate it. I realised it was a watermelon. It was pink inside with seeds, and was moderately sweet. So now I've got two left. Will they grow any more or should I harvest them now?

If the first watermelon seemed ripe, I'd harvest the other two right now, especially since it seems they may be eaten by an animal, if you wait. StuRat 23:22, 10 September 2006 (UTC)

Are full moons always in the east?

Recently I was driving home at dusk and was surprised to see the sun sinking in the east. I thought I'd taken a wrong turn. It was a few minutes before I realised I was not looking at the sun sinking, but at a bright full moon rising.

This made me think - as the sun had just gone under the horizon in the west, then it was in the right position to shine full-on the moon in the east.

So are full moons always seen in the east, half-moons in the north or south, and new moons in the west?

And would some extra-clever person be able to calculate from the astronomical data I have given where I was in the world, or what date it was? 81.104.12.47 21:21, 10 September 2006 (UTC)

That sounds about right, if you mean where the moon is just after sunset. Seems to me that the full moon would also set in the west just before sunrise. Melchoir 21:27, 10 September 2006 (UTC)

Yes, why couldn't you have a full moon in the west at sunrise or a full moon in the center of the sky at midnight ? StuRat 23:12, 10 September 2006 (UTC)

Chocolate allergy?

Hey all. Several years ago I noticed that eating chocolate would cause me to sneeze, usually only once or twice, within a minute or so of consumption. For a while now I've wondered what it is that is actually causing me to sneeze. I had a theory that how much I sneezed was dependant on the richness of the chocolate, but I can't say I've conclusively proven that. I assume this is an unusual case seeing as Wikipedia's allergy page makes no mention of sneezing or chocolate. Anyway, some answers please:

• Any suggestions on what precisely within the chocolate is causing the reaction?
• How unusual is it to a) have such a consistent mild reaction to something and b) to something as unusual (in terms of being allergic to) as chocolate?

Oh, and for the record, I am male, 17 years of age, and have eaten chocolate throughout my entire life. Hammer Raccoon 21:25, 10 September 2006 (UTC)

Are you allergic to chocolate? A true chocolate or cocoa allergy is rare.  --Lambiam^Talk 22:05, 10 September 2006 (UTC)

Also Photic sneeze reflex MeltBanana 22:30, 10 September 2006 (UTC)

It may not be the chocolate itself, but something else in it. Many chocolates say "processed with alkali", for example. StuRat 23:06, 10 September 2006 (UTC)

Satallites in orbit

How many satallite are there in orbit at any given time? how many man-made spacecraft in total are there out there in space?

Is this how to convert moles to grams?

Say you had a mole of Iron. It'd be the same as having 56 grams of it, right? Or if you had three moles of Sulfur, it would be 96 grams. Am I correct? --GUTTERTAHAH 21:42, 10 September 2006 (UTC)

You are very definitely on the right track! Mass = moles x (formula mass). --G N Frykman 21:45, 10 September 2006 (UTC)

Well yeh your right to the level of accuracy you have given your numbers, so yeh. Philc _T^E_C^I 21:46, 10 September 2006 (UTC)

Ah, good. That's one thing about chemistry I won't screw up <_< Thanks a lot! --GUTTERTAHAH 21:50, 10 September 2006 (UTC)

And if you have a molecule instead of a monatomic element, then you need to add up the atomic weights of each atom in the molecule. So for H2O, you would add the weight of two hydrogens and one oxygen, to get the molecular weight. This molecular weight is then multiplied by the number of moles to get the number of grams. StuRat 22:58, 10 September 2006 (UTC)

Real Talking Animals

Is the possibility of animals creating their own language in the next 100,000 years possible? Besides barking or meowing etc... or the fact that some birds were trained to talk. This may be more of an opinion question unless some theories have already been created by scientists. -MF14