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April 1

Electricity

What is the difference between coloumbs and amperes? This is for my revision, so if someone could answer this ASAP I would be very grateful! :)

New questions belong at the bottom of this page, not the top. However, cloumbs are units of electric charge, while amps measure how fast that charge is flowing from one location to another. See coulomb and ampere for the details. StuRat (talk) 11:20, 7 April 2008 (UTC)

Smelly puddle

<moved from misc desk> While the snowbanks from winter are melting away in spring, puddles of water will form on the roads and streets. Occasionally, the water in these puddles will give off a very nasty, stinky odour. I can't really think of a comparison with the smell, but it is a sharp, repulsive smell. However, the smell does go almost completely away after a while. What describes this phenomenal? Is it some sort of bacteria in the water? Thanks. Acceptable (talk) 20:57, 30 March 2008 (UTC)

One guess, an animal (hopefully) has defecated in the snow, it froze into a nice little popsicle, and then, when it warmed up, it melted into a nice bit of "mud". This will be quite fragrant until the bacteria break it down in a few days. StuRat 00:47, 1 April 2008 (UTC)

Apparent multiplying of mercury in body

A friend was telling me of how much his wife suffers from mercury poisoning,and one odd thing stoof out - it's taken years for it to get out of her system. Does it multiply by forming compounds with other things in the bloodstream or something? Does the mercury alter other cells? Or what? When he talks about how she has to swear it out, how the smell is on her clothes & such, and other things, it seems like the small amount of mercury she has shouldn't take tht long to get out.209.244.187.155 (talk) 00:05, 1 April 2008 (UTC)

Smell? SMELL? What does it smell like?

When liquid mercury is spilled, it forms droplets that can accumulate in the tiniest places; these droplets can emit vapors into the air that we cannot see or smell. —Preceding unsigned comment added by 79.76.208.103 (talk) 00:15, 1 April 2008 (UTC)

It's not that it smells, sorry; I just associate that witht he fact she has to take two long showers a day, soak in a sauna, etc. - there are other reasons for showering besides smell. :-) But, the main question is, what does the mercry do in the body that causes it to take so long to get out?209.244.187.155 (talk) 00:28, 1 April 2008 (UTC)

Which oaths does she use when swearing out mercury? Is it like "Out, damned spot!"? Edison (talk) 00:29, 1 April 2008 (UTC)

I wonder why she would have guilt over the mercury. Did she steal it? --Bowlhover (talk) 03:23, 1 April 2008 (UTC)

Without treatment for mercury poisoning, namely chelation therapy, the mercury will, indeed, take a very long time to leave the body. This is true of all heavy metals. The kidneys don't filter them from the body, so not much is removed in urine. I also don't believe a significant amount exits in respiration or sweat. This leaves things like skin flakes, hair, and fingernail clippings as the rather slow way to remove mercury from the body. StuRat 01:03, 1 April 2008 (UTC)

I once heard of a case where someone swalled metallic mercury and for some reason it stayed in their stomach and did not pass through to the intestines. This person was slowly being poisoned, not by the metallic mercury but by the vapours that came up from his stomach and then went into his lungs. I'm not sure but I think he survived.--Shniken1 (talk) 01:40, 1 April 2008 (UTC)

As for whether mercury can multiply over time, the answer is a definite no. Chemical reactions can only change the arrangements of atoms inside a compound, not the identity of the atoms. Iron, for example, cannot change into mercury. Unless your friend's wife absorbed additional mercury, the amount of mercury inside her body will decrease by the same amount that was expelled from her body. --Bowlhover (talk) 03:23, 1 April 2008 (UTC)

I assumed the questioner was asking if it can accumulate over time, which does happen if there is a continual source of mercury. StuRat (talk) 15:38, 1 April 2008 (UTC)

One of the more bizarre radiographs I've ever come across involved an individual who had – for no good reason and presumably while under the influence of intoxicating substances – injected himself intravenously with liquid metallic mercury. He had presented to the emergency room with persistent cough and a chest x-ray was ordered. His lungs were speckled throughout with bright, x-ray opaque spots. Here's a similar image: [1]. Google for 'mercury embolism' or 'mercury emboli' to find more case reports. TenOfAllTrades(talk) 14:57, 1 April 2008 (UTC)

A few years ago, I remember reading a news story about a mentally-ill man who had some sort of obsession with mercury and wound up in hospital after swallowing and skin-popping vast amounts of the stuff over a long period of time. IIRC, the hospital had to close down a whole ward for decontamination afterwards. --Kurt Shaped Box (talk) 22:20, 1 April 2008 (UTC)

chelation therapy is unproven science, the evidence of it's effectiveness is tenuous at best, you hear about it mostly along side other "alternative" medicines. -- JSBillings 11:21, 1 April 2008 (UTC)

I was under the impression that it is proven for certain limited uses (the article says it's licensed by the FDA), but that it's touted for uses where it's not proven (e.g. in autism). 81.174.226.229 (talk) 11:48, 1 April 2008 (UTC)

Both of the above responses are correct—chelation therapy is an appropriate, approved, and demonstrated effective treatment for certain types of metal poisoning (especially the heavy metals lead, arsenic, and mercury). It is also promoted by quacks for a range of other conditions for which it has no demonstable efficacy, including (and especially) autism spectrum disorders. TenOfAllTrades(talk) 14:57, 1 April 2008 (UTC)

Cassette speed

I've just bought Who's Next through the iTunes store and for whatever reason, I decided to compare it with my old cassette tape recording. I started to play both recordings at the same time. The first thing I noticed was that it sounded awful. The cassette was very noticeably higher than the aac. Then, it began to sound worse—the cassette was going much faster than the iPod. The two together made me suspect that my stereo is perhaps playing the cassette a bit fast, so I was wondering, is this normal? Are recordings sped up/slowed down from the originals, perhaps to fit more music on a smaller space? Or is it just my stereo? 66.21.215.126 (talk) 00:33, 1 April 2008 (UTC)

Cassette players can easily go the wrong speed. You could check the belts to see if they are on the wheels properly and are not loose. Graeme Bartlett (talk) 00:58, 1 April 2008 (UTC)

Or, the recordings could be different. Sometimes, for obscure marketing reasons, record labels will release different versions of the same album via different mediums (CD, cassette, vinyl, etc). Nimur (talk) 15:04, 1 April 2008 (UTC)

Turning a frog into a prince

Okay, say I had a frog and I wanted to make him a prince with *no* magic. In other words, say the technology existed to re-configure the cells changing frog organs into human ones, though not instantly like when a fairy godmother waves her magic wand. What would be the most difficult organ to change, assuming the frog had to be opened up to do this with? I'm guessing the stomach, so the guy wouldn't have to eat flies all his life, but I'm not sure. Would anything need added, or could something in the frog be used? Finally, how tall would this guy be when it was all said and done? Would he be tall enough to be a match for Thumbelina, anyway? (My question for April Fools' Day - but I am curious, too. Just don't say you can't give out medical advice :-)Somebody or his brother (talk) 02:35, 1 April 2008 (UTC)

Biggest problem I see with your plan is finding a country willing to have an ex-frog as regent.--Shniken1 (talk) 05:22, 1 April 2008 (UTC)

I'm not an expert in frog physiology, but I'd say the brain would be the most difficult organ to change. Not only would the physiological changes have to occur, but the learning necessary to have even a physically functioning individual would take decades. This won't be a problem if you don't mind having a brainless prince, which wouldn't be much different than we've got now in the States *rimshot*. — Ƶ§œš¹ _{[aɪm ˈfɻɛ̃ⁿdˡi]} 05:35, 1 April 2008 (UTC)

Agree, I don't think you can stuff that much neurons in such a small space to reproduce human intelligence--Lenticel ^(talk) 05:54, 1 April 2008 (UTC)

I may have misunderstood the question, but I think the question asker is wanting to change a frog into a normal sized and I guess fairly normal looking human. While the brain would indeed be a big problem, I have to say the whole thing sounds fairly unlikely to me. For starters, where would all the mass come from? It sounds to me like you're planning to more or less create a human out of thin air, the existing frog is most irrelevant Nil Einne (talk) 06:36, 1 April 2008 (UTC)

The user wanted a thumbelina escort so I think he/she means a frog-sized prince. Anyways there are lots of problems to where the mass could come from. The ideal mass would come from a fresh male human body with princely qualities. Note that neurons don't divide so we can't expand the frog's brain into the human skull housing.--Lenticel ^(talk) 07:01, 1 April 2008 (UTC)

Perhaps the frog's brain could be removed and replaced with technology. I suppose an AI could be used, but I prefer a wireless link to an existing human brain in a jar. If the brain previously belonged to a prince you may have also solved the royalty problem. APL (talk) 22:23, 1 April 2008 (UTC)

I suspect the easiest way to turn a frog into a prince is to feed the frog to a pregnant queen. -- JSBillings 11:12, 1 April 2008 (UTC)

There is, just, the technology now to reengineer living organisms in vivo, although changing a few proteins is the very limit of that right now. Recombinant DNA technologies, the mechanisms used in gene therapy, and in particular viral vectors allow you to alter the DNA of a living, mature organism. But doing this to affect wholesale change is a mammoth task (it's unfeasably huge, really), as you need to change every adult stem cell, and with a genetic payload vastly greater than a virus can carry. Even if you could jump that huge hurdle, you'd find the design of the intermediate forms of the frog-man would have to be very carefully done, so that each form was viable (just changing frog heart cells in to human heart cells won't make it grow a human heart). And even if you can do that, these genetic changes only apply when the cells are renewed. Nerve cells generally aren't, so your completed frog-man would still have the brain and nervous-system of a frog (it couldn't regulate its blood pressure, never mind move or think). You could engineer your organism to grow a fresh new CNS in parallel, a human one that the prince could use. But this transformation is so fundamental that you really can't say that the frog has turned into a prince, but rather that you've spent (wasted) a trillion dollars growing a human on the back of a frog. As you totally control the cell divsion, you can make frogPrince any size you want; as he's not much use to a princess unless he's normal size (or a big bigger, if you know what I mean) then he'd probably be a regular guy, except with the remnant of a little frog on his back. -- Finlay McWalter | Talk 12:42, 1 April 2008 (UTC)

Oh, I forgot. You also need to worry about telomere length, genetic damage, and other gene-level aging and cancer-causing problems. Really it's much more efficient for the princess to shop for a regular prince on the internet (Horsefacebook.com)' then she'll have a prince and a frog. -- Finlay McWalter | Talk 13:00, 1 April 2008 (UTC)

Once you turn your frog into a man, you still have the problem that he's not a prince. You would have to find a font of honour to do that job - a reigning King or Queen, for example, and persuade them to do the deed. Good luck! - Nunh-huh 21:49, 1 April 2008 (UTC)

I thought of another good way to turn a frog into a prince: Crown the frog's father King. -- JSBillings 23:38, 1 April 2008 (UTC)

The problem remains though that you're going to have to convince someone to take a frog or a frog-human (presuming you did the same for the father or mother) as king or queen. Given that on the whole, the monarchies of this world seem to be being reduced, not increased, I don't think it would be a simple matter even without the complexity of your candidate being a frog/frog-human Nil Einne (talk) 11:45, 2 April 2008 (UTC)

Yes I think that there would be a chance that a number of constituencies may elect a frog/human but I find it unlikely that said frog would be able to become prince (barring some Coup d'état, in which case he would probably name himself King not prince).

PS: apologies to people from those constituencies reading this.. Shniken1 (talk) 23:11, 2 April 2008 (UTC)

On second though you're right. I don't know about the examples you mentioned, but I think it would be fairly easy to convince some small town or whatever to elect a frog-human as an honourary prince/king/queen for publicity purposes. I mean let's face it, if you do manage to do this, there will be great interested in this frog-human. Of course you will also have to put up with all the religious and green protestors Nil Einne (talk) 06:56, 3 April 2008 (UTC)

Did excess water intake leads to kidney troubles?

I used to drink more & more water since long time. seeing this my mom is claiming that excess water intake leads to kidney truble as the water u drink will undergo filteration by them. may be she's true to some extent b'coz i used to urinate more frequently than any other else. that shows that my kidneys are working more as i'm drinking more water. so now should i stop taking that much water in order to safegaurd my kidneys. or is it just our hype? Temuzion (talk) 04:58, 1 April 2008 (UTC)

You might want to read our article on water toxicity. Wisdom89 _{(T / ^C)} 05:04, 1 April 2008 (UTC)

Note that the amount listed in the above article is more than 10 liters (around 2½ gallons) in a few minutes. You probably don't drink nearly as much water so quickly. The kidneys do process the water, true, but processing large amounts of water doesn't damage them. To the contrary, this may help to prevent kidney stones, which can indeed damage the kidneys, by diluting the materials from which kidney stones form to below the concentration where they come out of solution and form stones. Numerous studies have recommended drinking large quantities of water, on the order of 10 cups a day, for this and other reasons. The downside, of course, is that you will need to urinate more often. If you "hold it in", that could potentially cause a problem. So, assuming you drink around 10 cups a day and urinate as needed, you are correct and your mom is wrong. Go ahead and keep drinking water. StuRat (talk) 15:46, 1 April 2008 (UTC)

Please note that unusual thirst can be a sign of diabetes, so it is very important that you discuss this question with a doctor. The same is true for all other health matters – reference desk volunteers cannot give medical advice. --169.230.94.28 (talk) —Preceding comment was added at 16:00, 1 April 2008 (UTC)

U should know a point that this water drinking is not because of thrist but it was because i want to look attractive. I got many pimples on my face when i don't have the habit of taking so much water. But after starting intake of water in this way my pimples reduced & the face indeed becoming smooth. This was encouraging me to take more & more water. So r u sure that "over" processing of water won't lead to any kidney trouble. If u confidently say 'yes', I'll continue the habit. No question of diabetes once again I'm saying this because our family has a habit of consuming very less oil in our daily intake. My grand father has diabetes. So my father is taking all the measures he know in order to reduce the diabetic attack. Still at this 50+ age my father is very relaxed regarding sugar levels & we all are following that measures too. So now plz after considering all these situations suggest me the way I should go...whether to carry on or to stop? Temuzion (talk) 04:33, 2 April 2008 (UTC)

We can’t give you medical advice here. Talk to a doctor. --S.dedalus (talk) 05:31, 2 April 2008 (UTC)

How much water to drink each day isn't medical advice, it's dietary advice. With that in mind, go ahead and drink up to 10 glasses of water each day. It's good for you. Also, to help reduce pimples avoid fatty foods, especially trans-fats, which can clog pores. StuRat (talk) 13:08, 2 April 2008 (UTC)

Actually, although it's commonly believed by the general public that a diet high in fatty is a contributing factor, the evidence for that is quite weak. Check out Acne vulgaris. But fatty foods, particularly trans fats are bad for you in a number of ways so it would be a good idea to limit their consumption (or eliminate as far as possible in the case of trans fats). But particularly if you have a family history of diabetes, I wouldn't reduce it too much if it means your eating more refined sugars instead. Stress is definitely a contributing factor so whatever you do, don't worry too much about it, you'd just make it worse. Nil Einne (talk) 06:51, 3 April 2008 (UTC)

Can you cite any studies which disprove the link with trans-fats ? I'm skeptical that many thorough studies have been done, since there's no profit motive in proving that diet can prevent acne (although those selling acne meds might have a considerable profit motive to disprove this link). On the other hand, there are billions to be made by "proving" that medications can fight acne. The link is readily apparent for me. If I eat trans-fats, I have acne the next day. If I avoid them, my skin stays clear. I believe many studies in the past for fats or chocolate have failed to pick up the trans-fat link, since trans-fats are present in some fatty foods and chocolate, but not all. Those studies might tend to use fatty foods and chocolate without trans-fats, since it's unethical to give patients something harmful, and trans-fats are known to be harmful in other ways. StuRat (talk) 13:26, 3 April 2008 (UTC)

Drinking a lot of water is not medical advice, and the recommendation is probably a historical canard, see this BMJ article. I agree that it matters a lot about the reason why one would drink so much water. If it is out of persistent severe thirst, some medical problems tend to need looking into (diabetes mellitus, diabetes insipidus); if it is a bit of an obsession, OCD or psychogenic polydipsia may come into play. But on the whole, drinking a lot of water is not known to damage the kidneys. Absolutely excessive water drinking that exceeds the body's free water clearance may lead to hyponatremia, but in young people this is pretty hard. JFW | T@lk 23:37, 5 April 2008 (UTC)

What animals have adrenaline?

Is there some equivalent for insects, reptiles, etc? Mr.K. (talk) 08:56, 1 April 2008 (UTC)

I would imagine reptiles have adrenaline, along with any other vertebrates. You should read into the autonomic nervous system. —Preceding unsigned comment added by Mark PEA (talk • contribs) 17:12, 1 April 2008 (UTC)

Adrenaline (or epinephrine) is part of the monoamine neurotransmitter family. Animals throughout metazoa have various combinations of these. Some, for example octopamine, are neurotransmitters in invertebrates but only a trace amine in mammals. PMID 17142674 ←This paper interestingly discusses the genetic diversity and phylogeny of monoamine transporters throughout metazoa. If you're looking for the non-mammalian equivalent of the fight-or-flight hormonal action of adrenaline, PMID 17874113 deals with the "Evolutionary origin of autonomic regulation of physiological activities in vertebrate phyla". According to that paper, 5-HT plays the role in Aplysia that norepinephrine plays in mammals, for example. — Scientizzle 18:52, 1 April 2008 (UTC)

High output renal failure

Do we have an article on this ? It's a form of renal/kidney failure my Dad had. If I understand it correctly the kidneys first remove just about everything from the bloodstream, then put the water back in. In normal kidney failure the first step doesn't work, while in high output kidney failure the second step fails, leading to consumption of large quantities of water and production of large amounts of dilute urine. This condition is less serious than low output kidney failure because the toxins and wastes are still removed. StuRat (talk) 16:01, 1 April 2008 (UTC)

We don't have a separate article on it, but it's mentioned in the acute renal failure article (as nonoliguric renal failure). - Nunh-huh 22:03, 1 April 2008 (UTC)

All I see there is the phrase "although nonoliguric ARF may occur", is that all we have on Wikipedia ? StuRat (talk) 03:17, 2 April 2008 (UTC)

That's all I see. The ARF article should be expanded, and that's probably where the information belongs -- it's a type of manifestation with implications for treatment but not so important in terms of etiology or for classification. - Nunh-huh 04:27, 4 April 2008 (UTC)

OK, I'll add some info there. Is my description above essentially correct ? StuRat (talk) 14:21, 4 April 2008 (UTC)

The description of the workings of the kidney is correct, though simplified (might be nice in the kidney article). It's not quite right, though, to imply there's a perfect correspondence between disorders of filtration with low output renal failure on the one hand and disorders of resorption and high output renal failure on the other. While waiting for a renal expert, I'd suggest adding the following facts to the article: [1] oligouric renal failure = low output renal failure; non-oligouric renal failure = high output renal failure, with the usual amount of urine output qualifying as high output to be 400-600 ml/day. [2] changes in urine output do not correlate well with changes in GFR. [3] about 50-60% of all causes of ARF are nonoliguric. [4] the amount of urine produced may help to indicate the cause of renal failure (though these are only indications) [4a] anuria, in which <100 mL/day of urine is produced, can suggest urinary tract obstruction, renal artery obstruction, rapidly progressive glomerulonephritis, or bilateral diffuse renal cortical necrosis. [4b] oliguria, in which 100-400 mL/day of urine is produced, may suggest prerenal failure or hepatorenal syndrome. [4c] non-oliguria, in which the kidneys produce >400 ml/day of urine, may suggest acute interstitial nephritis, acute glomerulonephritis, partial obstructive nephropathy, nephrotoxic and ischemic ATN, radiocontrast-induced ARF, or rhabdomyolysis. -Nunh-huh 20:23, 4 April 2008 (UTC)

Thx. What are ATN and GFR ? StuRat (talk) 02:34, 5 April 2008 (UTC)

This sounds like diabetes insipidus. (ATN is acute tubular necrosis; GFR is glomerular filtration rate.) Axl (talk) 09:19, 5 April 2008 (UTC)

Interesting. How does one distinguish between this condition and high output renal failure ? StuRat (talk) 14:05, 5 April 2008 (UTC)

Looking at it this is not necessarily acute renal failure. Chronic kidney disease does not typically lead to oliguria, but the kidney may be poor at excreting solutes and still cause uraemia and metabolic disturbances. I think StuRat's explanation is very credible. JFW | T@lk 23:40, 5 April 2008 (UTC)

Diabetes insipidus is not acute renal failure-- but it is in the differential diagnosis of high urine output.

AFAIK high output acute renal failure (HOARF) isn't really that much different than oliguric ARF-- but it could be an article.

Major differences as I understand them...

• In HOARF volume overload is not a problem. The opposite may occur-- volume deficit, i.e. "dehydration".
• I think the prognosis is a bit different-- 'cause in HOARF there is renal tubular dysfunction (in addition to some glomerular dysfunction).
• The major difference between diabetes insipidus and HOARF -- glomerular function. In HOARF the serum creatinine will be elevated. In diabetes insipidus (DI) it should be normal. The conditions are quite different. DI, etiologically, may not be related to the kidney at all, i.e. central DI.

Nephron  T|C 12:57, 7 April 2008 (UTC)

Thanks.

So, has anyone changed any articles yet or created new articles ? If so, which ones ? StuRat (talk) 14:17, 7 April 2008 (UTC)

SDS-PAGE and Size Exclusion Chromatography

Before running a protein sample on an SDS-PAGE gel, you mix the sample with SDS and the SDS "binds" to the protein. There is also SDS in the gel I believe. My question is -- Let's say you mix a protein with SDS as above, but instead of running this sample on a gel, you run it through an SEC column -- Would the SDS stay associated with the protein or get separated from it? ike9898 (talk) 16:51, 1 April 2008 (UTC)

Ok, well, what you describe is never really done - and I think the reason is because the SDS will bind/coat the protein (I think in a 4:1 ratio if I remember correctly) and force the protein to extend into a linear rod like configuration. If you ran the sample over a gel filtration column using an inert buffer like HEPES pH 7.4, the SDS would remain with the protein, but the protein would probably run slower than the folded globular configuration since it would remain outside the pores. So, it might work, but you wouldn't know where the protein would come out - perhaps in the void volume. Wisdom89 _{(T / ^C)} 17:35, 1 April 2008 (UTC)

To clarify, I am asking because we have a sample that is giving us trouble with our SEC method. It is a sample of gelatin and a lot of the sample is coming off the column at a retention time that would indicate a MW of greater than 500 kDa. I think that this represents multiple peptides of less than 100kDa associated non-covalently. I'd like get the MW distribution of peptides when they are not associated like this. ike9898 (talk) 19:19, 1 April 2008 (UTC)

Gotcha, in that case I would use an non-ionic detergent such as Triton X-100 in your buffer. Also, you could trying using a high sodium chloride concentration along with beta-mercaptoethanol to disrupt the aggregation. Wisdom89 _{(T / ^C)} 19:24, 1 April 2008 (UTC)

How is DNA an acid?

Doesn't the phosphate make it a base? 128.163.170.163 (talk) 17:12, 1 April 2008 (UTC)

Phosphate is the ionized form of phosphoric acid, if you look at the DNA molecule and see the negatively charged oxygens in the phosphate group, you might think of it as a base, but the oxygen is negatively charged because the hydrogen (H⁺) has dissociated. --Mark PEA (talk) 17:24, 1 April 2008 (UTC)

Yes, since the proton in the phosphate dissociated, doesn't it make the DNA the conjugate base?128.163.170.163 (talk) 17:35, 1 April 2008 (UTC)

Yup, pretty sure that's the definition of a conjugate base. Wisdom89 _{(T / ^C)} 17:38, 1 April 2008 (UTC)

To the annoyance of biochemistry students everywhere, the convention for diagramming biochemical acids is to show the proton already dissociated, and bases showing an extra proton, often signified by a H⁺. When I angrily asked my professor about this during my undergrad years, he told me that this is because at physiological pH, DNA (being acidic) has given up its proton. It makes some sense, because the conjugate base isn't really all that basic, so it sort of shows that the acid has taken action. Of course, realistically, the acid and conjugate base form of DNA are in constant equilibrium, with the balance being in favour of the conjugate base. And from an organic chemistry context, being able to see the conjugate base sure is helpful in drawing resonance structures that explain the molecule's acidity in the first place!Vance.mcpherson (talk) 00:10, 2 April 2008 (UTC)

Pulmonary artery

On an episode of Dexter, Rudy has a girl in a headlock and squeezes a her neck with his arm, claiming that he is blocking her pulmonary artery, cutting oxygen from her brain and that she will be unconscious in a matter of seconds. I know its a TV show, but is this at all true? If so, how long would a subject stay unconscious for? This is purely out of curiosity I might add; I'm not planning to kill anyone just yet ;) —Preceding unsigned comment added by Crazy joke (talk • contribs) 18:59, 1 April 2008 (UTC)

The carotid arteries are those vessels which supply blood to the brain. Wisdom89 _{(T / ^C)} 19:20, 1 April 2008 (UTC)

The Pulmonary arteries are in the thorax near the lungs, so Rudy is way off. Yes, this WILL knock you out if your brain doesn't get oxygen. I'm sure if he held her long enough, he could cause permanent brain damage or death. However, I don't know how long it would take for the victim to recover. Paragon12321 (talk) 19:29, 1 April 2008 (UTC)

How long would it take to recover from death? I would say an infinite amount of time. —Preceding unsigned comment added by 79.76.250.241 (talk) 00:48, 2 April 2008 (UTC)

(edit conflict) If he really said "pulmonary", we have one more reason to support the writer's union. It's the carotid arteries that when occluded will cause unconsciousness. Some people never wake up from that, but almost everybody comes to in seconds with no lasting effects if the choke is maintained only briefly. Our article says that unconsciousness lasts for double the time the choke is held after the person passes out, unless they die, of course, or suffer permanent brain damage from ischemia. Other risks include physical damage to the neck itself, plaques in the arteries leading to stroke, and lung damage if you do it wrong. The guy's a serial killer, for cryin' out loud. Don't listen to him. --Milkbreath (talk) 19:31, 1 April 2008 (UTC)

Yeah, I think it was the carotid arteries he said. To be honest I just remember the arteries bit. BTW, thanks Wisdom89, Paragon12321 and especally Milkbreath. All you guys on the ref desk are the best! Crazy joke (talk) 19:38, 1 April 2008 (UTC)

I saw that episode, and I think you were right the first time, he did say "pulmonary". I remember thinking "don't they mean carotid" ? StuRat (talk) 20:29, 1 April 2008 (UTC)

I just checked StuRat, and he does say carotid artery. Looks like they did their research. Anyway, thanks everyone. Crazy joke (talk) 20:52, 1 April 2008 (UTC)

Where did you check ? Sometimes the script says one thing but the actors say another. StuRat (talk) 03:06, 2 April 2008 (UTC)

I'd downloaded the episode a while back. Its episode 11 of season 1. Crazy joke (talk) 19:17, 2 April 2008 (UTC)

Perhaps both of you are right. It's possible if this episode were from a DVD release for example, that it had been corrected if there was a mistake. I think this sometimes happensNil Einne (talk) 07:01, 3 April 2008 (UTC)

alternative to chloroform

Another question, again out of curiosity. I'm writing a short story, actually. What would be an alternative to chloroform? It has to be something that could be used to knock someone out, but that is undetectable and non lethal? I found this yahoo answers question which suggested something that is detectable, but that is not unexpected, like opiates in a heroin user, benzodiazepines in a benzo addict, GHB in a GHB abuser or alcohol in an alcoholic. The problem with these, in the context of my short story, is that they are not readily available chemicals, except for the alcohol which would be pretty hard to get into someone quickly and stealthily. Any suggestions? It doesn't have to be a chemical, it just has to get them unconscious Crazy joke (talk) 19:38, 1 April 2008 (UTC)

Nitrogen. They'll pass out without knowing anything's wrong. — kwami (talk) 19:45, 1 April 2008 (UTC)

Anything that goes under the "instead of oxygen" category is going to fail "non-lethal". Wholesale replacement of a room's atmosphere? Not very likely. — Lomn 21:43, 1 April 2008 (UTC)

Who said anything about likely? It's happened, though as you say, with lethal results. But chloroform would be lethal too in excess - question's in the timing. — kwami (talk) 00:08, 2 April 2008 (UTC)

If there were easily available substances that could reliably be used to knock people out non-lethally, they would be used by criminals. (There is a myth that this actually happens on sleeping-car trains, but if you look for specifics, nobody has any. It doesn't happen. See this message board thread for an example of such a discussion. Apparently it's easier for people to believe that they fell victim to a chemically-armed crook than to a quiet one.)

Of course a gaseous anesthetic will make someone unconscious, and so will replacement of oxygen in the air with something else; but, as already stated, it'd be very easy to kill the victim doing that unless you were very careful. --Anonymous, 00:33 UTC, April 2, 2008.

Is there a particular reason you eliminate chloroform? (Might help with suggestions if you told us.) Pretty much any general anesthetic will knock someone out. The two "classics" are chloroform and (diethyl) ether. Note, however, that "non-lethal" is dependant on dose - one reason chloroform and ether aren't used as anesthetics anymore is that the amount needed to knock someone out is very close to the amount needed to kill them. If you let your characters have access to medical equipment, your best bet would likely be some medical anesthetic. (If it's rare enough, it would be "undetectable" in the fact that no one would likely test for it.)-- 128.104.112.85 (talk) 17:05, 2 April 2008 (UTC)

Thanks all you guys! Yeah, I eliminated chloroform because its hard to come by and a bit old school. Saying that though, there are sites out there that tell you make your own chloroform. As Lomn and others pointed out, replacing all the air in a room is not practical, especially on a low budget. And chloroform risks killing the victim. Its important they don't die. If it helps the character is a teenager seeking revenge. She's a bit of a psycho and decides the best way to humiliate her cheating boyfriend is to knock him out and set him up. It has to be something believable though, as she later confesses to the police, so no Vulcan neck pinches! Unless of course that would work? Would it? BTW, (again from Dexter) would injecting something into the victim work? Dexter seems to have the nack of it. Anyway, a big thank you to everyone who contributed! You've given me some great ideas! Crazy joke (talk) 19:34, 2 April 2008 (UTC)

Well, the old "blow to the head" trick seems to work often enough, though it's not usually "undetectable". Or, you could give the boyfriend some type of allergy or other medical condition that the girlfriend takes advantage of to knock him out (like epilepsy). Mixing alcohol with some medications may also have the effect you desire, though I don't know which ones. Heck, depending on what she's planning she might be able to just do it while he's sleeping. Hope that helps! -- HiEv 12:29, 3 April 2008 (UTC)

Gas mileage

I'm trying to determine my minivan's gas consumption under various conditions. I have a 6 cylinder, 3.8L engine which idles at about 600 rpm. I need to know volume of vaporized gasoline is injected into each cylinder during the intake stroke. Does it vary among different engines? So far I have determined that the van will travel about 30 ft per mL. I want to know how fast it is using gas when I am stopped. —Preceding unsigned comment added by 66.120.95.34 (talk) 20:04, 1 April 2008 (UTC)

You want to know gas mileage while idling? The only way I can think of to measure this would be to fill up, let it idle for a few hours (so that a measurable amount of gas was used), then fill up again to measure. Then you can figure how much gas per hour is used while idling. Most people don't really care, tho. Why not just measure the mileage you get while driving? Friday (talk) 20:08, 1 April 2008 (UTC)

Isn't the answer obviously 0 miles per gallon when idling? Nimur (talk) 21:56, 1 April 2008 (UTC)

Well, yes. I should have said "usage" or something. Friday (talk) 21:57, 1 April 2008 (UTC)

The magic of google suggests a number between 0.5 and 1 gallon per hour while idling. Dragons flight (talk) 20:18, 1 April 2008 (UTC)

It's clearly a pretty small number. A couple of winters ago, when our house was without power for several days, we hooked up a big (750W) inverter to our Dodge Caravan (with the 3.3L V6) and set it "fast idling" in the driveway. It ran for hours and hours with what I thought was a surprisingly small consumption of gas. (1/4 of a tank?)

And I've thought about exactly the question posed here; I decided that if I were ever really interested, I'd wire into the solenoid valve on one of the fuel injectors and integrate the pulses. I'm pretty sure that modern electronic fuel injection systems run at a constant fuel pressure (unlike older mechanical fuel injection systems) so the integral of the injector's pulses should directly translate to fuel consumed. You could take a short-term moving average and display instantaneous fuel consumption or integrate over time and come up with total volume consumed. You'd have to wire-in carefully, though, lest you cause severe, expensive damage to your car's engine management computer. That's why I haven't performed the experiment yet.

Atlant (talk) 00:05, 2 April 2008 (UTC)

Something else you could try is to install a flow meter into the pipe between the gas tank and the engine (this is how the Mythbusters calculated their gas mileage). That way, you can get a direct measurement of how much gas you're using, without having to do any fancy math. — QuantumEleven 14:24, 2 April 2008 (UTC)

Depending on how the car is designed, that may or may not work. Some cars have the mechanical equivalent of a shunt regulator to regulate the pressure so they pump more gas than they need and dump the excess back into the tank (via a 'return" line). And cobbling a flow meter into the high-pressure gasoline line sounds like a much more dangerous experiment than tapping onto a 12V solenoid wire.

Atlant (talk) 15:40, 2 April 2008 (UTC)

Hedgehogs and breeding

In hedgehogs, who takes care of the young, the female, the male or both? Leptictidium (mammal talk!) 20:25, 1 April 2008 (UTC)

Yes but, first, you have to ask how hedgehogs make love! —Preceding unsigned comment added by 79.76.250.241 (talk) 01:05, 2 April 2008 (UTC)

I used to think they were silent creatures, but then I realized that they were affected by Sonic interactions. DMacks (talk) 03:01, 2 April 2008 (UTC)

Refdesk regular Kainaw's user page asserts "when it comes to hedgehogs, there are few people who know more than I do", so you might ask him/her if you don't get a good answer here. --Sean 13:40, 2 April 2008 (UTC)

The female takes care of the young. After mating, the males don't hang around. If, because of confinement, the male is near when the young are born, he will attempt to kill them. There are rare exceptions (just as there are cases where a dog raises a baby kitten). However, the rule is that the male is nowhere to be found once the babies are born.

There is always the joke about hedgehogs making love. Most people do not know that the male's penis slightly higher up his abdomen than where you'd expect his bellybutton to be. If humans were the same, our penis would be about two inches above our belly button. Because of this, the male doesn't have to completely mount the female in the same way that other mammals do. He only has to get half his body on top. -- kainaw™ 12:24, 3 April 2008 (UTC)

Spider eyes

Do spiders have eyelids? If not how do they keep them their eyes moist or protected? 200.127.59.151 (talk) 22:16, 1 April 2008 (UTC)

Well, some have no eyes, others have Compound eyes that don't have any eyelids. --Lenticel ^(talk) 22:26, 1 April 2008 (UTC)

Spiders have compound eyes? They don't look like compound eyes. Is there an anatomy drawing of spider eyes somewhere? 200.127.59.151 (talk) 22:51, 1 April 2008 (UTC)

If you shine a laser at a big wolf spider you only see a pair of eyes in front but almost to the sides. The reflected light is fairly intense and this is how I find spiders at night and other little creatures. 71.100.173.69 (talk) 23:19, 1 April 2008 (UTC)

I believe some spiders only have simple eyes, but some have both. — kwami (talk) 00:09, 2 April 2008 (UTC)

I'm sorry but this needs investigation. I can't find a reference that says spiders have compound eyes unless you take compound as meaning multiple individual eyes but that doesn't seem to fit our article's definition (or am I mistaken?). And it leaves the question of how the eyes are cleaned or moistened. 200.127.59.151 (talk) 01:44, 2 April 2008 (UTC)

I retracted the compound eye part, it seems that spiders evolved simple eyes per [2]. Somebody should fix the Spider anatomy article.--Lenticel ^(talk) 04:06, 2 April 2008 (UTC)

Do eyes necessarily need to be moist in order to function (ours do - but our eyes are not representative of all eyes)? I *think* I've seen spiders cleaning their eyes with their forelimbs - flies certainly do that. --Kurt Shaped Box (talk) 01:50, 2 April 2008 (UTC)

Another question about spider eyes

How and why did spiders wind up possessing six-to-eight eyes when most (all the rest of the?) creatures with what we would recognize as a face have only two? I'm looking for a slightly more in-depth answer than "they just evolved that way", if you please. :) --Kurt Shaped Box (talk) 22:44, 1 April 2008 (UTC)

This site [3] explains that in most species the eyes have different sizes and are thus able to focus at different distances and have different fields of view. The Daylight hunters sections says:

When hunting, the eyes of jumping spiders see in three different ways, using three different sets of eyes:

• The spider first senses movement of distant prey with the side eyes (PLE), which provide a blurry wide-angle image.
• Once movement is detected, the spider turns in that direction and locks onto the moving prey with the large, middle front eyes (AME). These eyes provide a clear, focussed telephoto image, probably in colour. The spider can track moving prey both by body movements and by using muscles to internally swivel the elongated eye capsules so that the light sensitive retina of each eye remains locked on the prey.
• While the spider stalks closer, it uses the side front eyes (ALE) judge the distance to the prey. When it judges the prey to be close enough (about 2 - 3 cm), the spider leaps.

200.127.59.151 (talk) 23:04, 1 April 2008 (UTC)

And this seems to show that the eyes are organised in formations of three pairs (the side eyes as a double pair). 200.127.59.151 (talk) 23:10, 1 April 2008 (UTC)

Cool about how jumping spiders use their eyes.

I guess the question is, Why do arthropods have multiple eyes, and why have spiders (other than jumping spiders) retained them? I imagine it has something to do with peripheral vision when your eyes (except for jumping spiders) are immobile. Crustaceans have mobile eyes, and AFAIK only two of them. — kwami (talk) 00:12, 2 April 2008 (UTC)

Can spiders turn their heads independently of their bodies to look at objects, as a matter of interest? If not, this could be another reason for requiring the expanded peripheral vision provided by multiple eyes... --Kurt Shaped Box (talk) 01:33, 2 April 2008 (UTC)

Unless I misread them, the links say that the spiders only have two body segments and so have to move their body to follow a prey that might leave their field of vision. It also says that appart from rare species, the majority have very poor eyesight relying much more on the vibration in their legs and hair to locate potential preys and threats. Like you said, it does make sense that the distribution of their eyes work as a way of expanding their basic field of view. Add to that the specialisation of each pair of eyes it seems to make a pretty efficient tracking device. Now thinking about how and why their multiple eyes developed in the first place sends my head into a spin. Maybe a good soul could provide us with the name of that spider that manages to scan very complicated paths in space and retain them all in memory before engaging on her journey. 200.127.59.151 (talk) 01:56, 2 April 2008 (UTC)

Portia. I think I saw the trait that you mentioned in the National Geographic Channel.--Lenticel ^(talk) 06:50, 2 April 2008 (UTC)

Multiple eyes

I seeeee youuuu with my little blue eyes...

I'll throw in a third. What other animals have more than two eyes? 200.127.59.151 (talk) 22:55, 1 April 2008 (UTC)

Depends on your definition of eye (any old photoreceptor cell?), but jellyfish have multiple ways of processing light information, sea stars have little eyes on their end of their stalks, clams have tons of eyes, as do scallops. But these are all pretty simple "eyes", save the scallop, who have lens-bearing eyes. --Captain Ref Desk (talk) 23:46, 1 April 2008 (UTC)

Ophiocoma wendtii is all eyes, so to speak. Cool, huh? --Kurt Shaped Box (talk) 01:38, 2 April 2008 (UTC)

Very simple eyes (small, lensless, and immobile) are only going to be of use on that part of the body, so you'd need a lot of them to see very much. The question really is, why have so many animal lineages reduced the number of eyes to just two? — kwami (talk) 00:14, 2 April 2008 (UTC)

My guess would be that eyes are "expensive" from an evolutionary point of view, though I recognize that is something of a tautological statement (durr, they didn't evolve because they didn't evolve). If binocular vision evolved first, then it would make a lot of sense that two eyes was the template on which other eyes were based. Binocular vision is common to most predators, so that wouldn't be too unexpected, and it makes for relatively easy 3-D imaging (not sure how well the brain handles multiple eyes in that respect; even spiders usually have two main, front-facing eyes for that reason). But obviously I'm not speaking with any real knowledge here, just speculation. --Captain Ref Desk (talk) 01:09, 2 April 2008 (UTC)

Hi. Some jellyfish have "eyes" across their body, but no brain. They will bump into white poles, turn around black poles, and avoid red poles. Don't try picking up even a dead jellyfish, they can still sting, but if you do make sure you pick it up by its bell and not its tenticles (especially if it's a box or irikanji jellyfish), and even if you don't feel anything, they can still be dangerous. Box jellyfish are perhaps one of the most poisonous creatures on Earth (if not the most venomous). They sting with millions of Gs (how do they do that?!). So, anyway, if I remember correctly some have around two dozen "eyes". Source: National Geographic on TVO. Hope this helps. Thanks. ~AH1^(TCU) 20:20, 2 April 2008 (UTC)

"Pins and Needles"

I'm not asking for medical advice, just to be clear. I'm wondering about something I've noticed since I was a child: when one of my legs "falls asleep", part of it "waking up" involves excruciating pain. It's kind of like a paralytic numbness, which apparently is typical, but what's different with me is that that is accompanied by this sort of unbelievably sharp tingling that subsides after a few minutes. I can avoid feeling it very much if I manage to keep my leg perfectly still for a few minutes as its waking up; the slightest shiver or pressure is crippling, though. I'm not at all worried about it, but I'm wondering because I've tried to explain this to friends and no one has ever known what I'm talking about. Any one? Thanks! —Preceding unsigned comment added by 96.232.160.116 (talk) 23:10, 1 April 2008 (UTC)

Well, "pins and needles" is apparently called paresthesia. It's not abnormal. I suspect the reason your friends don't know about it is because they don't suffer as many "asleep" limbs as you? My legs fall asleep very easily just from sitting in certain positions (my entire butt can even fall asleep), so I am very very familiar with what you describe (it's awful), whereas my wife can count on one hand the amount of times parts of her limbs have fallen asleep, and as a consequence has a much harder time talking about the experience. The page on it says that there are all sorts of horrible conditions that can be associated with but if one just has bad circulation you'd get the same thing (I'm pretty sure mine is just bad circulation, it's been like that since I was a child, and my doctor's tests always come back fine). Anyway, if it helps, I know exactly what you are talking about, I get it all the time, and I too have trouble explaining it to people who don't experience it, as it must be hard to imagine what it's like to have your whole leg (or both legs) feel like they are being jabbed with little sharp implements if you haven't felt it before. --Captain Ref Desk (talk) 23:39, 1 April 2008 (UTC)

Ah, interesting. I looked at the paresthesia page; I should have mentioned that. My friends get "pins and needles" (apparently, that's just the little numbness/tingling everyone gets when a limb falls asleep). The painful pins and needles is either something different, or we're just too sensitive! Knives and daggers maybe... —Preceding unsigned comment added by 96.232.160.116 (talk) 01:02, 2 April 2008 (UTC)

I notice a distinct difference depending on how "asleep" my leg is. For example, just a minute ago, I had my laptop on my crossed legs for a bit too long and my feet fell asleep. But they weren't very asleep, and "woke up" pretty quickly, and I only had very mild, non-objectionable pins and needles. However when my entire leg falls asleep for some time, usually because I'm cutting off some circulation via my rear (the toilet seat, I must admit, is the most common culprit of this for me—it's almost ideally designed to make my legs fall asleep), then I really get painful pins-and-needles.

All of which is to say that with my easy-to-fall-asleep legs, I notice lots of variations in how intense the pins and needles are, and it seems to matter (for me) exactly how much circulation I'm cutting off. --Captain Ref Desk (talk) 01:12, 2 April 2008 (UTC)

Earth's magnetic field

If you loaded a big boat up with permanent magnets or a giant magnetic coil would the boat begin heading for the closest magnetic pole? 71.100.173.69 (talk) 23:12, 1 April 2008 (UTC)

In theory, yes. In practice, I suspect that even the proverbial boatload of magnets would exert an extremely small pull. Here's why. Once the boat has turned to line up the magnets with the Earth's field, the remaining force will be proportional to the difference in the value of the Earth's field at the two ends of the magnet. A magnet in a uniform field won't feel a force; any force is from the gradient (change) in the field. JohnAspinall (talk) 00:44, 2 April 2008 (UTC)

Hi. Well, there's also the problem of sinking if the boat gets too heavy, and bumping into land or ice is also a possibility. However, if you magnetise a steel needle, place it into a cork, and float the cork on a tub of water, it will start pointing towards the north pole. Metal objects in water can do some amazing things (besides sink). For example, if I put some paper clips containing metal in water and let the surface tension to float them, they sometimes become attracted to each other, stick together, and even sink to the bottom together. Also, there may be areas in the water in the ocean where methane is released, and causes boats to sink, and people that jump out sink too because the water itself has lost its bouyancy. Hope this helps. Thanks. ~AH1^(TCU) 20:27, 2 April 2008 (UTC)

A floating magnet on Earth would experience Torque which would tend to cause it to rotate to align with the Earth'sd magnetic field. It would not move toward the magnet because the repulsion would counteract the attraction. If you could find or create a Magnetic monopole, which no one to date has done, then it would move. Edison (talk) 21:02, 2 April 2008 (UTC)

You can use the torque of the magnetic spin for propulsion to move you in any direction you wanted, but then you would need to apply energy to move the magnet back away from the direction of the field.--Dacium (talk) 01:38, 3 April 2008 (UTC)

So to use the Earth's magnetic field for propulsion you would have to somehow use the torque from the spin of the magnet to propel the boat forward instead of just making it point North/South. 71.100.173.69 (talk) 02:54, 4 April 2008 (UTC)

effect of sugar water

Q What is the effect of sugar water on a plants growth? Bailey504 (talk) 23:15, 1 April 2008 (UTC)

Glycolysis. -- JSBillings 23:26, 1 April 2008 (UTC)

Might attract hummingbirds for pollination too. --Kurt Shaped Box (talk) 23:27, 1 April 2008 (UTC)

Program to create legal and medical troubleshooting charts

Not really sure where to put this question since it involves mathematics, science, humanities and business. Anyway here goes... I have written a computer program to apply the method described in Optimal classification for identifying flags to identifying actions. The program can handle a large number of actions, conditions and multiple states, which makes it suitable for use in creating legal and medical troubleshooting charts. All I need to publish such troubleshooting charts are legal and medical logic tables. I could in the alternative publish just the program. How would I go about doing this in the shortest amount of time while preserving my rights to the program? 71.100.173.69 (talk) 23:56, 1 April 2008 (UTC)

I have no idea what a lot of that means, but a trick for retaining a copyright (besides simply declaring the copyright) that was shared with me by an author some years ago is this: Print a hard copy, and send it by registered mail to yourself. Don't open it. That way, in the event of dispute, a court of law has a federally attested post-mark date by which it can determine the document's correct age. I've never done it, but it sounds reasonable... Vance.mcpherson (talk) 00:16, 2 April 2008 (UTC)

See Poor man's copyright for why it isn't reasonable. As to the original question, this is basically asking for legal advice, which we aren't allowed to give here. --Anonymous,00:18 UTC, April 2, 2008.

Since you have not charged me any money I do not think anyone can claim it as legal advice, which would otherwise be a fruadulent claim since clarification of the law is simply not. 71.100.173.69 (talk) 05:51, 2 April 2008 (UTC)

Clarification - The reference desk will not provide legal advice. This has nothing to do with charging for services. See Wikipedia:Legal disclaimer for further information and explanation. Nimur (talk) 13:56, 2 April 2008 (UTC)

There are ups and downs to either business model; the one that will likely get you the most profit is also, non-coincidentally, the one that will cost you the most in terms of time and personal investment.

I deplore software patents (because I think they stifle creativity and are used maliciously) but that's the strongest way to preserve your rights. As for copyrighting the program, that's not hard to do; the hard part about copyrighting is enforcement (that is, it'll be up to YOU to take offenders to court and to prove that they are infringing on your specific code). --Captain Ref Desk (talk) 01:41, 2 April 2008 (UTC)

Since my objective is to see that both medicine and law are published in the form of a troubleshooting chart the program is only incidental as a means of optimizing the charts. I love free software as well but the reality is that I have worked long and hard to create it at my own expense and without any compensation so I can not in all due respect to myself release it free of charge.

While software patents may stifle creativity for the end user they may provide incentive and promote creativity for the author. I have copyrighted and published the program and required the user to obtain a key but have since withdrawn the demo and limited versions from publication. Now I'm thinking of using it only as an in house tool and merely offering the service of optimizing any troubleshooting chart. 71.100.173.69 (talk) 05:51, 2 April 2008 (UTC)

I don't think they stifle creativity with the end user, I think they stifle creativity with other authors. Would you even know if your program infringed upon another software patent, unintentionally? It's entirely possible, that without knowing it, some aspect of your work may have done so. That's the danger of software patents—they aren't like machine patents where you can easily figure out what the prior art is, and the bar for creating new software is a lot lower than creating new engineering methods. I have no problem with authors making money or being successful, but I think software patents make software development and commercialization a legal minefield for all involved (which is why so many companies take out so many software patents just routinely: they're afraid of getting sued by someone else). --Captain Ref Desk (talk) 00:43, 3 April 2008 (UTC)

The difficultly of assessing who is the rightful owner and who is not may be more difficult for the legal system but all the government really cares about is whatever the software gets published instead of remaining a trade secret for in-house use only. In fact I would prefer to keep it a trade secret and only offer the service it supports rather than publishing it as I have done other stuff cost free and that is what I now think I should do in this case - keep it unpublished as a trade secret. 71.100.173.69 (talk) 03:05, 4 April 2008 (UTC)

April 2

Angle

What angle does water make with a capillary tube? —Preceding unsigned comment added by 71.175.123.209 (talk) 00:21, 2 April 2008 (UTC)

See Contact angle my friend. Any trouble understanding, please come back here. —Preceding unsigned comment added by 79.76.250.241 (talk) 00:37, 2 April 2008 (UTC)

Killer strangelets

What the problem with so-called "killer" strangelets here[4]? Julia Rossi (talk) 01:14, 2 April 2008 (UTC)

It has been suggested that strange matter could convert all normal matter on the Earth into strange matter in a chain reaction, something like Ice-nine. See Strangelet#Dangers. Someguy1221 (talk) 01:22, 2 April 2008 (UTC)

Well, that certainly does sound unpleasant. :-/ --Captain Ref Desk (talk) 01:47, 2 April 2008 (UTC)

I'll really start to worry when 'they' decide to start exploring the potential military applications of strange matter chain reactions... --Kurt Shaped Box (talk) 01:53, 2 April 2008 (UTC)

Before you panic, see Safety at the LHC — Kieff | Talk 02:29, 2 April 2008 (UTC)

Can I get a shout of "Well, they would say that, wouldn't they?"? ;) --Kurt Shaped Box (talk) 02:43, 2 April 2008 (UTC)

Well, and that's really what the lawsuit is (ostensibly) about—not so much saying it will happen as it is saying that "they said it won't happen, but we think they should take a more thorough look at it." (One could argue, as the CERN people no doubt do, that the lawsuit is just nonsense, and it may be. All I'm saying is, that's what they're saying on the face of it.) The basic argument of CERN is, "if it could have happened, it already would have happened", which is in some ways comforting and some ways not, though for my money I don't think there's going to be a problem. But I am not a physicist. --Captain Ref Desk (talk) 02:48, 2 April 2008 (UTC)

"I get drunk every night and walk home down the white line in the middle of the road at night whilst wearing black - if I was going to get hit by a car, it would've happened by now". ;) --Kurt Shaped Box (talk) 14:13, 2 April 2008 (UTC)

I see two solutions - (1) slap a warning label on it: "Caution: Use of this device may result in the destruction of the universe. Handle with care." or (2) Let them run the damn thing, and if it does kill us all then hit them with a class action. Confusing Manifestation(Say hi!) 05:20, 2 April 2008 (UTC)

Who needs government think tanks when there's you guys, the think tins. I thank you.  : ) Julia Rossi (talk) 06:26, 2 April 2008 (UTC)

The last report I saw quoted the odds as 1 in 10,000,000,000,000,000,000,000,000,000,000,000,000,000. Unfortunately I can't link because it's from a now-defunct article in the NZ Herald. AlmostReadytoFly (talk) 08:49, 2 April 2008 (UTC)

So, if someone has demonstrated that there *is* a chance that 'Something Very Bad That Cannot Be Undone' might happen when the machine is started up - then why are they still planning to do it? Will this experiment benefit humanity in any real sense - or does it basically boil down to "We want to poke it with a stick and see what it does"? --Kurt Shaped Box (talk) 14:06, 2 April 2008 (UTC)

Please take a careful look at that figure. Consider Orders of magnitude. Note that it is greater that the number of microseconds since the Big Bang. Assume that physicists would not spend billions of Euros on a whim and consider that they might have a reason, rather than giving a knee-jerk anti-science reaction. Consider reading about the Higgs boson and the LHC and the Standard Model. Think about the size of the number again. It's longer than the odds of winning the lottery jackpot five times out of five. I don't think you grasp how vanishingly small the chance is. AlmostReadytoFly (talk) 14:49, 2 April 2008 (UTC)

It wasn't my intention to sound 'anti-science'. I know very little of particle physics and my eyes tend to glaze over whenever I attempt to learn more about particle physics - even the links you have provided are scarily complex (heh, they should publish a 'Particle Physics for Dummies' book). I was attempting to question the practical benefits of these experiments - I personally don't believe that a risk (even an infinitesimally tiny risk) to all life on this planet can be justified for the sake of an experiment, if the end result will only be of interest to the practitioners of particle physics experiments themselves and people who read books about particle physics. My question, from a position of ignorance - if they carry this out and it works, what will the new knowledge enable us to do (in a real world sense) that we couldn't do before? --Kurt Shaped Box (talk) 20:18, 2 April 2008 (UTC)

But then you're asking science experiments to obey far, far, far stricter conditions than anything else. Just because you can put a number to the risk doesn't mean it's worth worrying about. As for what technological use the results will be, we don't know. Quite likely very little (at a moderately uneducated guess). As for what technological use the process of designing and building the experiment has been, I don't know, but I'm curious (see below). But if the results aren't what's expected then you could argue that particle physics and the Standard Model are broken. 81.174.226.229 (talk) 07:53, 3 April 2008 (UTC)

It's a reasonable question. According to the laws of physics as we currently understand them, nothing bad will happen. Even if the LHC uncovers some new and unexpected physics, it is only creating events in a controlled way that happen naturally through cosmic ray interactions anyway, so it is still very unikely that anything bad will happen. However, the LHC will be operating at the boundary of known physics, so there is a very, very, very small chance that something bad will happen. But you can balance this very, very, very small risk against the possibility that a better and more complete understanding of particle physics could eventually lead to solutions to the very much greater dangers of global warming, destroying the ozone layer, running our of fossil fuels or being wiped out by a dinosaur killer. Poking things with sticks is what makes us human. Gandalf61 (talk) 15:01, 2 April 2008 (UTC)

To be a bit more polite than I was above... The UK regulatory body for nuclear power plants sets a limit of <10^-4 public deaths per year for one plant, and a target of 10^-6 (I believe these numbers are "handed down" from IAEA). Assuming 10^10 (10 billion) people on Earth and that the risk of 10^-40 applies for the first year of operation, that's a risk of 10^-30, a factor of 10^24 less than a roughly equivalent target. AlmostReadytoFly (talk) 15:16, 2 April 2008 (UTC)

Do you drive a car? I'm going to make a very conservative estimate/lower limit for the number of pedestrians a single car driver can be expected to kill within a year from now in one special way which is hardly avoidable (other than by not driving a car). Chances for getting unconscious without a warning (e. g. some neurological disorder not known to the person in question) within 1 year: 1 in 1 billion. Time spent in the car: 1/100 of the total time (less than 15 minutes a day). Fraction of the driving time when one has to break due to a pedestrian on a zebra crossing: 1/1000. Fraction of the cases of sudden unconsciousness in front of the passing pedestrian where the car actually hits and kill the pedestrian: 1/100. Expected casualties per year: 10^-16. That's more than 10¹⁴ times as much as from the estimate for LHC, and a very conservative estimate for one single well-behaving car driver. Icek (talk) 22:55, 2 April 2008 (UTC)

The anthropic principle basically says "the universe had to work out well for creating intelligent life; otherwise we wouldn't be here to discuss it". I hereby proclaim the misanthropic principle: "it doesn't matter if we wipe out all intelligent life, because we won't be here here to discuss it". :) --Sean 13:50, 2 April 2008 (UTC)

Large Hadron Collider#Safety concerns may be of interest Nil Einne (talk) 06:45, 3 April 2008 (UTC)

Low-gravity humans?

I'm reminded of this question by the recent news about the Virgle Project: Supposing that Mars is terraformed and permanent human settlements are established, what would be the physiological effect of the planet's low gravity on the generations of humans living there, having been gestated and raised there? Would they become taller and more gracile, as I read in some science fiction book? Would they be unable to walk on Earth? --Lazar Taxon (talk) 02:27, 2 April 2008 (UTC)

Probably yes to all your theories. The effects of microgravity on physiology are quite real and detrimental to any return to full Earth gravity. Mars' .38g will, naturally, have less impact, but the impact will be nonetheless real. Note, however, that training could probably overcome the last (walk on Earth). — Lomn 03:08, 2 April 2008 (UTC)

The colonists would certainly need to exercise more than those remained on Earth, to have the same physical strength. --V. Szabolcs (talk) 09:27, 2 April 2008 (UTC)

I spent three years there on the Virgle pilot project. We were all fine when we came back. Franamax (talk) 05:55, 3 April 2008 (UTC)

What is the Fabric named "armalith" made from (or how its made), and what are the benefits of its use?

I saw a website that showed a video of some pants made from it with a person sliding on pavement and the "armalith" was very resistant to damage. The website is www.esquad-jeans.com

My google search had very little information and wiki had nothing.Nusaince (talk) 03:19, 2 April 2008 (UTC)

"The jeans are made entirely from a fabric called Armalith, which is claimed to be “the most resistant of all textiles” and is blend of cotton and high-tech fiber. The website doesn’t disclose the “high-tech fiber,” but the tag inside the jeans says its polyethylene -- yep, plastic. Probably an ultra-high molecular weight polyethylene (known as UHMWPE) that is so strong and elastic it has replaced Kevlar in bulletproof vests."[5] DMacks (talk) 03:28, 2 April 2008 (UTC)

Right [6] shows in a basixcally unreadable small text the ultra-high molecular weight polyethylene (known as UHMWPE) as the backbone of the blue denim fibers.--Stone (talk) 06:34, 3 April 2008 (UTC)

At the same weight, armalith is more resistant to abrasion than leather. The internet site features a video where we can see a biker falling at a rather high speed. Then when he stands up and displays is jeans to the camera there is barely any damage done to it. There is another video where a 4 tons Hummer is lifted by the jeans. The interesting fact about Armalith is that is looks and feels like plain denim.

Acetone combustion

What is the combustion equation for acetone in air? 71.100.173.69 (talk) 05:10, 2 April 2008 (UTC)

Is this a homework question? The burning of a hydrocarbon or a compound containing only hydrogen, carbon, and oxygen will always produce carbon dioxide and water. [7] The chemical formula of acetone is CH₃COCH₃ and combustion in air always involves oxygen, so finding the equation should be easy. --Bowlhover (talk) 05:45, 2 April 2008 (UTC)

No not homework, just curious about whether or not it could be used as a camp stove fuel or for that matter as an ICE fuel. 71.100.173.69 (talk) 21:49, 2 April 2008 (UTC)

Well, complete combustion will always produce... But incomplete combustion can produce all sorts of weird things (most notably including carbon monoxide).

Atlant (talk) 15:44, 2 April 2008 (UTC)

Beware of using acetone for stove use, as it is very volatile, as the whole stove heats up the acetone will boil rapidly and flames will combust out of control. The acetone will boil over and you will then get a fire ball. Graeme Bartlett (talk) 01:56, 3 April 2008 (UTC)

Surely acetone is not as volatile, as say, propane, which gasifies almost instantly at standard temperature and pressure? In any case, when dealing with fuel, use necessary caution. Nimur (talk) 15:44, 7 April 2008 (UTC)

Pipe - Solar Heating System - for homes

I want to make a cheap solar heating system for homes using pipes only and a pump motor that circulates the water which is all connected to a geyser. The pipes will be connected in parallel like a big web and sit on the roof. What kind of pipe would be suitable, what kind of plastic? Does it have to be weather proof and high pressure and able to take high temperatures? Is copper pipe better, maybe with a black plastic coating on the outside? What length of pipe would be effective? I want to help the poor who cant afford normal solar panel or tube heating systems and I also want to help combat global warming. Any advice or help would be greatly appreciated. Thanks so much.

--CrypticApple (talk) 09:15, 2 April 2008 (UTC)

You confused me when you mentioned a "geyser", so I'll ignore that. I would think clear plastic pipes would be most effective, with some dye added to the water to make it absorb heat from sunlight. You would want the pipes to be flattened so they can absorb as much sunlight as possible. Special outdoor plastic must be used so it won't deteriorate when exposed to UV light. One potential problem is that the water could freeze in cold weather and burst the pipes. Some type of antifreeze would need to be added to prevent this. Since you're concerned about the environment, I'd suggest a nontoxic antifreeze. You still have the problem of how to power the pump. Solar panels could work for this. Another approach is to make the pump child-powered. In Africa they have child-powered water pumps that are hooked up to merry-go-rounds. This allows the excess energy children have to be put to good use. I wouldn't expect the pipes to get to boiling temperature, and there are many plastics that can take those temps and pressures. Copper would be a poor choice on the roof because it would radiate heat. However, it might be a good inside choice, although it's relatively expensive. Some type of sealed radiators could also be used. (They must be sealed as you wouldn't want the antifreeze leaking inside the house.) One big flaw is that there is no sunlight at night when the heat is needed the most, especially in winter. This would require a storage tank to store the heated water until night. The children's merry-go-round could lift the heated water into a water tower at night, then gravity could allow it to flow through the house into a lower tank at night. StuRat (talk) 12:44, 2 April 2008 (UTC)

One of the key characteristics I'd look for in my piping is the ability to resist solar radiation over the years. For example, in the US, "Schedule 40" PVC piping would be an awful choice because it rapidly becomes brittle when exposed to the sun. (Plus, of course, it's white, so maybe if it were painted black...) Clear piping sounds like a poor idea to me as well because clear liquid in clear piping wouldn't absorb much heat. You might want to see our article on solar collectors (although it's pretty scant).

Atlant (talk) 15:50, 2 April 2008 (UTC)

...and that would be why I suggesting adding dye to the water. That way all the heat is generated directly in the water, versus on the outside surface of the pipe, from which only a portion would find it's way inside the pipe, while most would radiate back into the air. This is especially true of plastic pipes, since they don't transfer heat well. That's a good quality once the heat is inside the pipe and you want to keep it there, but it's a bad thing if the heat is outside and you want to let it in. StuRat (talk) 16:59, 2 April 2008 (UTC)

It's probably worth reading Solar hot water. -- Coneslayer (talk) 17:06, 2 April 2008 (UTC)

Though water is mostly transparent to visible light, it's a pretty good absorber in the medium-wavelength infrared range, which is where much of the sun's energy lies. I don't expect that dye would have much of an effect. jeffjon (talk) 20:18, 2 April 2008 (UTC)

I've read somwhere that in places like Isreal they use ponds with a freah water layer and a salt water layer beneath. The reash water layer acts as insulation while the salt water absorbs heat. Salt might work in place of a die. I know for sure that chromium oxide will. 71.100.173.69 (talk) 22:05, 2 April 2008 (UTC)

Well, that might work with several feet of water, but with only a few inches in a pipe you'd need to make it more absorbent of sunlight. Enough dark dye to make it opaque at all frequencies would do the job nicely. StuRat (talk) 03:17, 3 April 2008 (UTC)

Exercising while taking human growth hormone supplements

This question has been removed. Per the reference desk guidelines, the reference desk is not an appropriate place to request medical, legal or other professional advice, including any kind of medical diagnosis, prognosis, or treatment recommendations. For such advice, please see a qualified professional. If you don't believe this is such a request, please explain what you meant to ask, either here or on the Reference Desk's talk page.

This question has been removed. Per the reference desk guidelines, the reference desk is not an appropriate place to request medical, legal or other professional advice, including any kind of medical diagnosis or prognosis, or treatment recommendations. For such advice, please see a qualified professional. If you don't believe this is such a request, please explain what you meant to ask, either here or on the Reference Desk's talk page. --~~~~

You should speak to your pharmacist or the prescribing physician about the effects of any medication or supplement on your health and activities. TenOfAllTrades(talk) 17:23, 2 April 2008 (UTC)

Heartbreak

My heart is completely broken and I cannot function because my other half does not want to be with me anymore. We have been together for several years. It feels like I am dying inside and food tastes like sawdust. What, if any at all, are there any benefits for a human to endure this? Is there some sort of biological benefit to this?--Jonasmanohar (talk) 18:35, 2 April 2008 (UTC)

If all food tastes like sawdust, then it becomes easier to eat more healthy-yet-tasteless food instead of delicious-yet-nutritionally-vapid food. I'd call that a biological benefit. — Lomn 18:47, 2 April 2008 (UTC)

No obvious evolutionary advantage occurs to me for the downside of intimate relationships. However you probably can't have the good without putting up with the bad, and the usefulness of a pair bond should be fairly apparent from a biological perspective. Friday (talk) 18:53, 2 April 2008 (UTC)

I think your somewhat correct except that the downside is part of the evolutionary advantage. The emotional attachment between two people in a relationship is part of what keeps them together in a happy, stable relationship best suited for raising offspring. If they did not form this emotional attachment, or it was somehow possible to form an emotional attachment without feeling bad when it breaks up, it just wouldn't work as well. Either way, there would be far less to hold the relationship together Nil Einne (talk) 06:42, 3 April 2008 (UTC)

If your other half is in fact your conjoined twin, we can't give you medical advice beyond saying that you should see a doctor immediately. Ben Carson's good. --Sean 69.134.209.199 (talk) 19:22, 2 April 2008 (UTC)

There are several evolutionary approaches to depression, not that I'm diagnosing you or anything...That page gives a few theories as to why it's not easy to be happy. Someguy1221 (talk) 19:28, 2 April 2008 (UTC)

We are absolutely not permitted to provide any counseling or medical advice at Wikipedia Reference Desk. Anyone seeking counseling would be far better served by consulting his physician. Edison (talk) 02:54, 3 April 2008 (UTC)

Yes, the questioner is obviously looking for someone to allow them to say "well, I may be sad but at least there's an evolutionary explanation!" Couldn't the anticipated pain from the severence of a "pair bond" be an additional motivation to maintain such a bond? — Ƶ§œš¹ _{[aɪm ˈfɻɛ̃ⁿdˡi]} 05:09, 3 April 2008 (UTC)

Humans are social creatures by nature, which is a fantastic survival trait. Having that social bond broken is distressing, and (speculating here) encourages the individual to find new social bonds. A lone individual in the wild is less likely to survive than one in a group, even a group of two. There's also some studies that animals with higher brain functions are mentally harmed by a lack of interaction with others, such as parrots plucking out their own feathers and other forms of self-mutilation. Without going into medical advice, that's the main evolutionary functions I can think of. -- Kesh (talk) 03:14, 4 April 2008 (UTC)

analysis of acidic and basic radicals

i am a student of chemical engineering... is wanted to ask what should be the correct procedure to carry out analysis of acidic and basic radicals??? —Preceding unsigned comment added by Enjay88 (talk • contribs) 22:15, 2 April 2008 (UTC)

consultancy companies and engineering graduates

i am a engineering student and aspire to get placed into a good consultancy firm....i wanted to know what is the criteria for selection of engineering graduates in a consultancy firm?? —Preceding unsigned comment added by Enjay88 (talk • contribs) 22:45, 2 April 2008 (UTC)

I have hired graduates in the past, but not for chemical engineering. The basic thing of course is their accademic results in detail. Not just whether they got their degree, but whether they got High Distinctions instead of just scraped passes. The second aspect is interest, whether the applicant is really showing interest in the job (or something like it) or will take any job. Othere important thng will be how well the applicant can write - sounds like it will be relevant for consulting, so have some good examples of your written work. Some referees would be good too, in order to tell how dilligent the worker is, and whether they are punctual, or have emotional problems. Any kind of work history at this point is relevant too, even for some job nothing to do with the new one. Graeme Bartlett (talk) 02:04, 3 April 2008 (UTC)

April 3

skin disease

I remember a horrifying image on wikipedia of a skin disease in which your skin grows super fast and doesn't fall off, and it foams or something.. there was a picture for the article and it looked like the guy had like feathers over his hands and he looked like a bird; the skin had gone like a foot past the tips of his fingers. What disease is that? :D\=< (talk) 00:01, 3 April 2008 (UTC)

I think its called Froth —Preceding unsigned comment added by 79.76.255.69 (talk) 01:06, 3 April 2008 (UTC)

I remember the pic – an Indonesian man I think, and a specialist medic offered to treat him. It wasn't catching, but I can't remember the ref, only that it might have been on the ref desk. Julia Rossi (talk) 01:30, 3 April 2008 (UTC)

I think the disease was warts, human pappiloma virus. Graeme Bartlett (talk) 02:07, 3 April 2008 (UTC)

Ah found it thanks http://blog.wfmu.org/photos/uncategorized/easterneuropeskincondition1c.jpg :D\=< (talk) 04:20, 3 April 2008 (UTC)

You may be thinking of Dede. We used to have an article on him, but it got redirected to Epidermodysplasia verruciformis after an AFD. Bovlb (talk) 05:06, 3 April 2008 (UTC)

Lemon peel eating rodents

Is there a critter known for eating (very cleanly) only the peel off a lemon? Several (25 or so) lemons were either partially or fully peeled, both on and off the tree. No evidence of any peel pieces or poop. No reference found on the net, experts at the nursery had never seen it. San Francisco Bay area.

milkshark66Milkshark66 (talk) —Preceding comment was added at 00:41, 3 April 2008 (UTC)

Just my guess, nothing all that specific, but if I'd have to wager a guess, I'd say that it was most likely an insect of some type. I know that's not really helpful, but it might narrow it down some. Wisdom89 _{(T / ^C)} 03:21, 3 April 2008 (UTC)

This paper might be helpful [8]. Wisdom89 _{(T / ^C)} 03:23, 3 April 2008 (UTC)

Here's another guess: citrus peel miner, but a little out of your area. Call your local agricultural office or a university botany/ag department. I'd bet they'll be all over it (especially if it's new). Franamax (talk) 05:28, 3 April 2008 (UTC)

Citrus peel miners eat within the peel, they don't remove it, so they are probably not the cause. Milkshark66, you might also consider the possibility it's a prank of some sort. Look for shoeprints, ladder prints, or other indicators to see if the lemons could have been tampered with by people. Generally most insects find the peels toxic and most animals find the peels unpalatable, which is what makes me suspect human intervention (especially just after April Fools' Day). -- HiEv 09:48, 3 April 2008 (UTC)

ZOMG April citrus fool miners! Block all IPs! Stop the site! But wow, chewing the peel off 25 lemons, that's a dedicated trick. Certainly didn't stop the predator, those lemon trees need to do some evolving. :) Franamax (talk) 10:06, 3 April 2008 (UTC)

Homosexuality

What "causes" it? 143.43.8.32 (talk) 03:24, 3 April 2008 (UTC)

Read Homosexuality specifically Homosexuality#Why some people are gay or lesbian and you might find Biology and sexual orientation helpful. The Dominator (talk) 03:45, 3 April 2008 (UTC)

Kevlar

If Kevlar sublimates at 450 degrees Celcius, what are the properties or uses for the gas created? Who would know this? —Preceding unsigned comment added by Nusaince (talk • contribs) 03:35, 3 April 2008 (UTC)

In an oxygen atmosphere, the decomposed monomers would probably be useless. However it appears that if you do it in argon you can improve batteries! I found this by googling "kevlar heat decomposition". Franamax (talk) 05:21, 3 April 2008 (UTC)

Kevlar is a polyimide and it does not sublimat, but decompose on heating. The imide bonds break and lead to several compounds like carboxylic acid derivates and others. I have a GC-MS plot of the pyrolysis of Vespel which is not so much different. If you are lucky, by choosing the right conditions (no oxygen), you get a residue which is a carbon fibere. The article mentioned above is about this carbon fiber not about the gas evolving.--Stone (talk) 06:18, 3 April 2008 (UTC)

Stone, you sound like a good candidate then to update the Kevlar article where it says "At 450°C Kevlar sublimates.", which I found a little questionable (why I said "decompose" above). If you can throw in a reference when you update it, all the better! Franamax (talk) 06:47, 3 April 2008 (UTC)

inter and intra generalation equity

what is inter and intra generalation equity ? —Preceding unsigned comment added by 211.30.50.68 (talk) 03:55, 3 April 2008 (UTC)

You mean Intergenerational equity? William Avery (talk) 11:29, 4 April 2008 (UTC)

Benefits so far from LHC

The space race fuelled the development, amongst other things, of miniaturised computers, communications satellites and (one would guess) detector technology. Do Ref Desk people know of any things so far which have been developed for the LHC and have found wider use? AlmostReadytoFly (talk) 08:04, 3 April 2008 (UTC)

First of all we should note that the Large Hadron Collider is not yet complete or online. Second, the LHC is meant to deal with large amounts of energy and forces that have never been produced by man before, so much of it has no other application. Also, the LHC is not the first particle accelerator. The Intersecting Storage Rings (ISR) at CERN was the first hadron collider, and it began running in 1971. So, most of the pioneering in design has occurred in the earlier colliders. The ISR, for example, was the first use of stochastic cooling. The real benefits from the LHC will come after June 2008 when the experiments begin, and the big ones are noted in the "Research" section of the LHC page. Due to all of those reasons I would not be surprised if there were no or almost no wider use applications due to the LHC so far. After the experiments begin, then you'll see the benefits probably 10-20 years later. -- HiEv 09:39, 3 April 2008 (UTC)

I know that it's not yet online, but the question relates to the work which has been necessary in the design and build phase, not the research which is planned. AlmostReadytoFly (talk) 09:46, 3 April 2008 (UTC)

To clarify: I wasn't aiming for abstract future things like everything we predict about the Standard Model being wrong, but important things like better detectors in the x MeV to y MeV range, or yes, stochastic cooling. (the above comment is to be read in a slightly ironic way ;) ) AlmostReadytoFly (talk) 10:00, 3 April 2008 (UTC)

This page and its links might help you. It mentions:

• an innovative micro-duct optical fibre cabling system.
• novel 1.8 K refrigeration units based on advanced cold compressor technology.
• a novel method of cost-effective rust protection of steel. Gandalf61 (talk) 10:18, 3 April 2008 (UTC)

Cool, that's just the sort of thing I meant. Thanks. AlmostReadytoFly (talk) 11:21, 3 April 2008 (UTC)

Particle accelerators, in general, don't have a lot of side commercial benefits, not as many as other areas of research, anyway. Historically the biggest benefits have probably been in the area of mass spectrometry, which is extremely useful for chemical analysis, and the early work on the atomic bomb, which spun in part out of Ernest Lawrence's particle accelerator laboratory in Berkeley. But in terms of investment, they are a lousy way to get commercial benefits, and cannot really be justified in those terms (and, to my knowledge, never are). (They also don't have many direct military benefits either, though historically having a strong experimental physics community and pool of physicists has been seen as indirectly beneficial for military programs. I'm reminded of Robert R. Wilson's justification for Fermilab before the JCAE; see his page for the quote) --Captain Ref Desk (talk) 13:38, 3 April 2008 (UTC)

I attended a lecture from a guy who worked at the LHC. This was part of a course I did on grid computing, and all the previous lectures had been from other scientists who thought that grid computing was a nice idea but wasn't going to/ hasn't yet actually worked in practice. Anyway, due the mind boggling amount of data that the LHC will produce it will need an equally massive amount of computing power to analyse that data (the only way they could hope to do it when they were planning the LHC was to rely on Moore's law to catch up with what they needed during the time it took them to build it). And it seemed like the people at CERN have been the only people smart enough to actually get grid computing to work in a practical way, and as warm-up/testing to get ready for when the LHC comes online they have been doing various scientific research using their grid computing computer farms. Here is the website for this stuff: http://lcg.web.cern.ch/LCG/ Tomgreeny (talk) 17:05, 5 April 2008 (UTC)

Protecting a rose petal from coffee

I would like to coat a rose petal with something that does not melt in coffee and leaves the rose petal looking like a rose petal. Is it possible?Bastard Soap (talk) 09:43, 3 April 2008 (UTC)

Something edible? kwami (talk) 10:01, 3 April 2008 (UTC)

No, don't plan on eating the rose petal. Why do they taste good?Bastard Soap (talk) 10:09, 3 April 2008 (UTC)

People can make rose petal jam (preserve) with them. There's [9] and if you google rose petal recipes there's heaps more. But one petal is no biggy---about the petal, couldn't you just let it float on the coffee as it's served? Coating it with something (like crystallised with sugar) could sink it. Just guessing. Julia Rossi (talk) 11:47, 3 April 2008 (UTC)

It really only needs to float until it is served, correct? Once the person starts drinking, they will likely ignore the rose petal - if they even leave it in the coffee. I would use a wax. They melt at different temperatures, but usually float. There are many edible waxes. Beeswax is one. I'm not sure how well it will float though. -- kainaw™ 12:34, 3 April 2008 (UTC)

You might try some sort of water-proofing spray, like you'd find in a camping store. I have no idea at all if that would work. You might try explaining exactly what you're trying to achieve. You could probably entirely enclose a rosepetal in some sort of acrylic cube, also if that's what you're going for. APL (talk) 16:04, 3 April 2008 (UTC)

Isn't water-proofing spray somewhat toxic? 206.252.74.48 (talk) 16:53, 3 April 2008 (UTC)

out of the can it is toxic, but set silicones may not be, there are some silicone cooking gadgets, such as muffin tray. A problem with wax is melting in coffee! ALso the petal can cook in a hot drink, so it may have to be impregnated, not just coated. A plastic rose petal might do! Graeme Bartlett (talk) 21:30, 3 April 2008 (UTC)

Suffice to say, anything you could coat it with would likely either melt, or be toxic to human consumption. Most folks wouldn't recognize a lone rose petal anyway, and complain about something being in their coffee! If this is a romantic gesture, it'd be better to just include the rose itself (maybe with a shortened stem) tied to the handle of the coffee mug with some twine or something. Sans the thorns, of course! -- Kesh (talk) 03:20, 4 April 2008 (UTC)

Blinking light

Okay, I am Raglan, New Zealand, and I can currently see a blinking light in the sky. It is roughly east-by-northeast of me, and appears maybe 10 cm (rough estimate) above sea level. It is the same size as any star. It somewhat resembles the light of an aircraft, possibly a little brighter. It is maybe as bright as the two or three brightest stars I can see in the sky (clear sky, no light pollution). There is a blinking/twinkling effect to it, but the brightness remains constant. The blinking has a red tinge to it (ie when it pulses, it is distinctly red). The light has been stationary in the sky for at least 10 minutes. I tried looking at it through a telescope, but everything is dark so I could not find it. What is it? --superioridad ^(discusión) 10:17, 3 April 2008 (UTC)

Oh, and at least one other person agrees with my description of it, so I doubt I am hallucinating or somesuch. --superioridad ^(discusión) 10:19, 3 April 2008 (UTC)

More: I have not been watching it constantly, rather, checking on it every few minutes, so there may have been some slight movement that I have not noticed. It is currently about 11:20 pm. --superioridad ^(discusión) 10:23, 3 April 2008 (UTC)

Hmm...I bet a rubber chicken that it's a sateliteBastard Soap (talk) 10:26, 3 April 2008 (UTC)

I'll take that bet. Bright satellites are in low earth orbit and typically cross the sky in a minute or so. They also have to be able to "see" the sun in order to reflect sunlight, so they're normally visible at dusk and dawn, not 11:00 pm. To remain fixed in the sky, a satellite would have to be in geostationary orbit, and I don't think any of those satellites are visible to the naked eye. Heavens-Above.com can give you a list of bright satellite passes at your location. -- Coneslayer (talk) 11:50, 3 April 2008 (UTC)

Looks like someone might have lost a rubber chicken. 206.252.74.48 (talk) 16:53, 3 April 2008 (UTC)

The fact that it's low on the horizon is a clue. I'd say it's a reflection of a terrestrial (or naval) blinking light off the clouds. If it's out at sea I'd say it's a ship or buoy. StuRat (talk) 13:14, 3 April 2008 (UTC)

If I'm not misunderstanding you, there are 2 problems with the suggestion of a blinking light being reflected off the clouds:

(1) Light spreads out over distance, so the image projected on the clouds would be extremely large in angular size and dim, not at all like a point source of light.

(2) The OP said the light was changing colours but maintaining constant brightness, not blinking. --Bowlhover (talk) 07:59, 5 April 2008 (UTC)

It could also be a weather balloon.TheGreatZorko (talk) 14:15, 3 April 2008 (UTC)

I'd be more concerned about your belief that you're a town... Clarityfiend (talk) 19:27, 3 April 2008 (UTC)

Silly English language, leave out one 2-letter word and the meaning is completely different. —Preceding unsigned comment added by 206.252.74.48 (talk) 20:35, 3 April 2008 (UTC)

Raglan's not a town, its a way of life :1 Boomshanka (talk) 21:21, 3 April 2008 (UTC)

Hi. Well, I saw a weird object in the sky last night too. However, let me check the sky atlas to see if it might just be a star. Well, judging by your location, Arcturus and Antares may be close. They're both reddish. Antares would have appeared east-northeast, but are nowhere near the three brightest stars from that location: Sirius, Canopus, and Rigil Kentarus, actually the 3 brightest in the sky. Arcturus would have appeared north-northeast, but is the fourth brightest in the whole sky. However, both would have been well above the horizon, but I suggest you check Yoursky and enter your coordinates and time yourself, as I could be wrong about which star map in the atlas to use, thus they might have been low on the horizon. Why a star? One time I mistook Capella for a UFO. It was blinking red and green, probably a twinking effect, and was about 20 deg above the horizon. Hmm, have you seen this any other night? Maybe it's a faraway but bright tower on a nearby island or something that pulses light, such as a lighthouse. Hope this helps. Thanks. ~AH1^(TCU) 22:45, 3 April 2008 (UTC)

It might be a tower, but I don't thiknk it's a lighthouse. This is a map of all lighthouses in New Zealand. The nearest one in the correct direction is #33, which, measuring from Google Maps, is about 70 km away. --Bowlhover (talk) 06:33, 4 April 2008 (UTC)

Assuming New Zealand lighthouses are about the same size as Atlantic Coast lighthouses in the US, that would put the lighthouse right at the edge of visibility. --Carnildo (talk) 20:26, 4 April 2008 (UTC)

The OP, though, specified the unidentified light to be "10 centimetres" above sea level. If he or she meant ten centimetres at arm's length, that's about 6 degrees. Assuming the light was from lighthouse #33, a trigonometrical calculation arrives at a minimum height for the lighthouse of 7 km. It's the minimum height because, at 70 km, a significant portion of the structure would be blocked by Earth's curvature. --Bowlhover (talk) 07:59, 5 April 2008 (UTC)

Diffraction

According to me diffraction can be explained by particle nature. The bending of light can be because of collision of photons (particles) with each other when they move. The dispertion of light when it travels through a door can be explained by the fact that the photons are under the influence of the force of attraction (short range) by the walls of the door. So those photons which passes close to the door frame will experience a outward force which pulls the photons away from their path and this causes diffraction.

If i am wrong , please explain the defect in this theory. —Preceding unsigned comment added by Nkbspidy1991 (talk • contribs) 11:10, 3 April 2008 (UTC)

It doesn't explain diffraction peaks, and why they are spaced in terms of wavelengths, or why you get them even in single-photon experiments (where photons can't collide.

If you wanted to test the "attraction to doors" part of your hypothesis you could build an experiment with very thick slits. If diffraction works by attraction, then the beam should be pulled into the side of the slit, and not make it out. AlmostReadytoFly (talk) 11:19, 3 April 2008 (UTC)

Your theory also doesn't explain laser beams, which stay together better than white light because all the light is the same frequency, so there is no wave interference. StuRat (talk) 13:00, 3 April 2008 (UTC)

Actually no theory explains that phenomenon, StuRat, because it doesn't occur. Laser beams are subject to the same laws of diffraction as any other waves. Because of their high coherence they often operate at the limit of diffraction, whereas white light beams are typically spatially incoherent enough to be limited by geometrical optics, but that is a different story. --169.230.94.28 (talk) 15:42, 3 April 2008 (UTC)

Gene therapy

Is it possible for or through the use of gene therapy to change a physical feature or characteristic? —Preceding unsigned comment added by 198.188.255.2 (talk) 02:07, 3 April 2008 (UTC)

I don't think it is, as of today, but if you're asking if it might ever be possible, I'd say yes. Although, unlike in sci-fi, the change won't be immediate, but will take time. This might be years in the case of a major change. StuRat (talk) 12:54, 3 April 2008 (UTC)

neuronal tracts in our body...

all the tracts in our body after descending from brain cross to the opposite side at some level or other to control the opposite side of the body..what is the significance of that? what will happen if fibres are not crossing? —Preceding unsigned comment added by 59.93.13.89 (talk) 15:16, 3 April 2008 (UTC)

If you have tracts on the brain, you need to stop answering the door when the cultists knock. :-) StuRat (talk) 16:16, 3 April 2008 (UTC)

But seriously, I think it's just an accident of biology. There isn't any advantage to doing it this way, but the disadvantage (a slightly longer neural pathway) is so slight that there isn't much evolutionary pressure for it to be changed. My guess is that if anybody ever had nerves that didn't cross over like this, they would be just fine. StuRat (talk) 16:16, 3 April 2008 (UTC)

If someone injured the right side of our ancestors head and caused slight brain trauma without unconsciousness, the left side of the brain could still see and respond to the threat with the right limbs. Some (tiny) survival value in that. Edison (talk) 18:50, 3 April 2008 (UTC)

This is a very interesting question, and, in fact, one of great inetrest for neuroscience and medicine. However, first of all, I must note that many, but certainly not all the "tracts" innervate the contralateral (opposite) side. Among the sensory pathways, as far as I know, auditory crosses over almost fully, visual crosses over so that the opposite half of the visual field (rather than opposite eye) is represented, and olfactory crosses over very little or not at all. Among the motor pathways, innervation via the spinal cord is "opposite" but innervation by cranial nerves is not necessarily so. Motor part of the trigeminal nerve is represented bilaterally (that is, on both sides), for example. As far as the "significance" part goes, the significance for the contralateral representation of the visual field was explained by Santiago Ramón y Cajal. The explanation is simple: the lens of an eye produces an inverted image on the retina; if the optic pathway did not partially cross over, the two halves of the image would not have matched. The inervation of limbs then crosses over as well, to match the visual input. The detailed explanation by Rodolfo Llinás is here. Hope this helps. --Dr Dima (talk) 19:27, 3 April 2008 (UTC)

That last link requires a subscription. Is it available anywhere for free ? StuRat (talk) 20:04, 3 April 2008 (UTC)

Found it! Here, enjoy. --Dr Dima (talk) 22:19, 3 April 2008 (UTC)

Thx. StuRat (talk) 14:17, 4 April 2008 (UTC)

asbestos pipe

Since the risk of death from breathing asbestos is so severe full body protection is used to provide for disposal of any possible secondary sources of contamination, however, contact with asbestos from water in water supply pipes appears to be of no concern. What is the difference in contact of asbestos in the lungs and in the gut? 71.100.173.69 (talk) 19:27, 3 April 2008 (UTC)

Well, the health problem from asbestos is specifically that long-term exposure deposits asbestos crystals into the lungs, causing asbestosis or mesothelioma, over a long period of time, so of course people who work with asbestos in their jobs need to wear the suits (they are constantly going to be inhaling it otherwise), though that doesn't mean that one time of doing such is going to end up with instant death otherwise. I am not sure, in any case, that asbestos around supply pipes would get into the water supply in appreciable levels—if the pipes allows their insulation to leak into them I doubt they'd be great at holding in water.

Anyway, I don't know if consuming asbestos is a good idea but if sounds like it will just be flushed out of the system. In any case, they won't get into the lungs if they are just in the water supply. When thinking about toxic risks it is important to think about the pathways in which the risks act. All plants, for example, contain a number of radioactive isotopes in them (e.g. bits of polonium, among other things). In food, though, they pass through the body as waste and are not a problem. When burned and inhaled, as in cigarette smoking, they can become lodged in the lungs and sit there radiating, causing great harm over a long time period. Something that is fine in one situation becomes toxic in another; it's probably incorrect to generalize too widely about this, but it seems to apply in particular to things that take a long time to develop into a fatal disease, and in situations where they would in one context be flushed out as waste but in another are allowed to accumulate. --Captain Ref Desk (talk) 18:54, 3 April 2008 (UTC)

Asbestos -cement pipe was widely used in the US and other countries after World War 2 because it is cheaper than iron pipe and does not rust (although it corrodes in its own way). It is no longer manufactured in the US, but one town at least still imported and installed it in the 1990's. Phoenix New Times 1994 In 1988, 65 million people in the US got their drinking water through asbestos cement pipe totalling 300,000 miles. The pipe was 15 to 25% asbestos by weight. New York Times, 1988 The US EPA sets a max alowable exposure level of 7 million asbestos fibers longer than 10 microns per liter of water US EPA. The same source says one source of such asbestos in drinking water is the cement asbestos water pipes. How many liters of water does one consume in a year? Asbestos is actually a component of some water pipes, rather than insulation around metallic or plastic or concrete pipes as Captain Ref Desk seems to suggest. If the pipe is worked on or damaged, the asbestos fibers become friable and could contaminate the water per [10] . Holes are drilled in large supply pipes to make service connections. The instructions say workers should provide a means for flushing out the fibers downstream before they enter the premises. Do workers always follow official procedures? Asbestos from pipe can also enter the drinking water through corrosion [11] . In some locations where pipes deteriorated, levels of over 300 million fibers per liter were found. Anniston Star, 2005 Asbestos fibers in tapwater may be released into the air and inhaled [12] as from vaporizers. I could not find readily a government or other reliable source that said any of this was a health hazard in general, but there are certainly advocacy groups which are alarmed about it. Edison (talk) 09:41, 4 April 2008 (UTC)

an extra star in the big dipper?!

Hi. Last night, I was stargazing, when I looked towards the big dipper, I saw an extra star. I'm familiar with the constellation, so I know that star shouldn't have been there. First of all, I estimate its visual magnitude to be somewhere between +2.0 and +3.0. Its celestial coordinates, as I checked on the star atlas, were approximately RA 14h 20m, DEC +52°, with an uncertainty of roughly 2 degrees. I watched the object for about 30 seconds to make sure it stayed, took another 30 seconds or so to check the star atlas and try to point the telescope at it, but it was gone. After this, I thought I saw it again but much fainter, although it could just have been an [illusion or a non-medical placebo, which happens sometimes when I think a really faint star is there but really isn't. I have relatively poor vision, and live within a light-polluted neighbourhood in southern Ontario, if that helps. When I tried to point the telescope toward or near the object or where I thought I last saw it, I keep coming to a scalene triangle of three stars in my low-power eyepiece, most likely Nu Bootis, Iota Bootis, and Kappa Bootis. Checking the star atlas, the object was also likely to have been close to NGC 5480 and NGC 5474. The time was roughly between 9:20 and 9:30 PM EDT, April 2, 2008, which is 1:20 - 1:30 UTC time, April 3. I watched the object for roughly 30 seconds for any obvious movement in case it was a plane or satelite. I noticed no obvious movement, although I may or may not have seen a slight drop in brightness. All I know is, it didn't flash like a plane, and didn't seem to move like a sattelite. I didn't see movement in that time, but if there was any movement, it couldn't really have been faster than 6 arcminutes per second. As for colour, I'm not sure I remember seeing any obvious colour, however it could have been slightly tinted some colour, so don't count that out of the question. I'm not sure about the duration, but I think it probably lasted 30 seconds or longer. All I know is, when I first went outside to stargaze at roughly 8:50 pm, it wasn't there. I calculate the change in brightness at roughly the time of observation to be about 0.2 - 3.5 magnitudes per minute, dropping in brightness at the time of observation. I'm not sure if it was any larger than a pinpoint object, but if it was of any size, it could have appeared no larger than 40 arcminutes in diametre. I thought it was fuzzy at one point, but it could easily be an artifact (when I look at stars, they look like they have rays coming out of them. It makes it difficult to recognise objects like comet Holmes, but wearing glasses at one point turned the comet into a pinpoint light source). I'm not sure, but it's possible I may at one point have noticed an object of roughly magnitude 3, roughly halfway between Mizar and Alkaid, and perhaps another magnitude 4 or so object roughly a degree closer towards Alkaid than the original object, or I could have caught a glimpse of Nu or Kappa Bootis. However, these could easily have been an illusion, although the original object is likely much too bright to have been an illusion. I can often see fainter objects and have better angular resolution when there's less light pollution and glare. So, what could it have been? Let's list and examine some of the possibilities:

• a satellite?

Hmm, interesting possibility. Well, the problem is, it likely wasn't the ISS, as the only ISS appearence around that time last night was lower in the sky, close to Cassiopeia and Draco and nowhere near Ursa Major. As for Iridium flares, Heavens-Above only lists them to mag. 0 and brighter. I have no time to check nearby areas for flares, but these flares generally last only 15 seconds or so, and their movement and change in brightness should be obvious. What about other satellites? Well, out of all the satellites brighter than mag. +3.5 visible at this time, only one passes through Ursa Major: Lacrosse 5. This seems to pass pretty much exactly through the place I observed the object, it passed through the area at about 15 arcminutes per second. Also, when I looked again in about 30 seconds, it was gone, and an object that moves so slowly, if at all, shouldn't have dissapeared so quickly (although the that area of the sky was only about 20 degrees from being obscured by a terrestrial object). It was also high enough in the sky to not be one of those bright horizon-hugging satellites that never appear on the Heavens-above because they're so low.

• an asteroid or comet?

Well, it looked fuzzy at first, but comets don't just suddenly vanish. Asteroids don't either, and this also wasn't listed on Heavens-above like the other asteroids. In order for it to be an asteriod passing really close to the Earth and naked-eye, as well as covered by the Earth's shadow in order for it to dissapear so suddenly, seems unlikely. JPL nasa lists 2008 FH5 passing near the Earth on April 2, but being 7.6 LD away and 11-24 m is not going to maked it naked-eye.

• a gamma-ray burst?

Hmm. Well, there was this burst around two weeks ago in Bootes that was briefly visible to the naked eye for around 30 minutes to maybe a lucky observer. However, that one only reached mag +5.8 or so, and I doubt one could look so bright from Earth unless it was close to us. Wikipedia would probably have an article on such a GRB if it happened, but lists no such thing.

• an erratic variable star or nova?

Well, I don't see a variable star like that in the star atlas. Novas are quite often unpredictable, but I don't think one would last mere seconds to no longer than probably half an hour, unless it got covered by dust or something, and such a bright nova would probably have been reported by someone else already.

• An illusion or misremembering?

Probably not. I first noticed this object when I glanced at Ursa Major, so it's probably not a floater or similar object, and I didn't require averted vision to look at it for about 30 seconds, and I didn't notice any movement. Although I may have seen similar objects closeby such as the ones described earlier, this one is likely too bright to be an illusion. The combined magnitudes of the three stars in that scalene triangle of Nu, Iota, and Kappa, total about magnitude +3.0, and perhaps I got a glance of that, but it doesn't explain why it appeared just as bright as some of the other Big Dipper stars, why it stayed for a whole 30 seconds, and why I didn't see it before or after this observation. Also, I jotted down notes about the object right after I came back inside, and misrememberings and dreams don't just leave papers titled "unidentified stellar object".

So, what do you think it might have been? Please note that I am not immune to errors in observational astronomy. For example, a few years ago, I mistook the Pleadies for Delphinus, one time I mistook Capella for a UFO, and another time I mistook Venus for Planet X. However, I'm better at this now, and I'm pretty sure I saw this last night. Can someone help suggest what it might have been? Thanks. ~AH1^(TCU) 22:30, 3 April 2008 (UTC)

Just 2 random and unlikely suggestions:

• A satellite in a high orbit which displayed one of its very rare flares.
• A collision of 2 asteroids.

Icek (talk) 23:56, 3 April 2008 (UTC)

I've two questions for AH:

(1) Was the stellar object as strongly affected by astronomical seeing as the other stars? If so, it likely has a small angular diameter; if not, it likely has a large diameter.

(2) For how long did you were you looking at the object?

Icek: the collision of two asteroids is definitely very rare. I don't think there has even been an observation of such an event before. However, according to http://members.aol.com/_ht_a/hattonjasonp/hasohp/GEO.HTML, flares from a geosynchronous satellite can definitely reach magnitude 2-3. I suppose bright flares are even more frequent for medium-Earth-orbit satellites. I've never observed a flare made by high-orbiting satellites, though, so I have no idea how quickly their brightnesses change. --Bowlhover (talk) 05:55, 4 April 2008 (UTC)

The other bit regarding the asteroid collision: why would this be visible? We're not talking about movie effect giant-TNT-asteroids-in-oxygen, just two rocks. Nothing would generate light. As to the original question, I'm not enough an expert to offer an opinion. — Lomn 14:20, 4 April 2008 (UTC)

• Any collision of two objects, unless it's totally elastic like two ideal billiard balls bouncing off each other, converts some kinetic energy into heat, and if there's enough heat then the objects will incandesce. Consider an asteroid, with known mass M and speed V, made of solid basalt, with a specific heat c = 0.84 kJ/kg K, or 840 J/kg K in SI units. It collides head-on with another identical asteroid moving with speed V the other way. The relevant reference frame is the one relative to their center of mass. Each object contributes kinetic energy MV²/2 to the collision. The greatest possible temperature increase would be when all of that energy goes into heat (the collision is totally inelastic, like two globs of ideal glue colliding and sticking together). Then if the heat warms all parts of each asteroid equally, the temperature increase ΔT is ((MV²/2)/(Mc) = V²/2c. Note that the M's cancel. So the speed to produce a given temperature increas e is V = sqrt(2cΔT). Making the rock incandescent would require it to be warmed by probably at least 1,500°C = 1,500 K, which would require a speed of sqrt(2×840×1500) m/s (isn't the coherence of SI neat?) That's 1,600 m/s or about 3,600 mph. A collision at 5 times the speed, which is still within the range of possibility, would produce 25 times the energy and 25 times the temperature increase for a totally inelastic collision. Except that a totally inelastic collision at even the lower speed is also totally unrealistic. Asteroids aren't all that strong and they don't have a lot of self-gravity to make the pieces come back together. What would really happen is that the asteroids would be shattered and pieces would fly off in all directions. It's conceivable that some pieces would be heated more than others and might incandescence, but I don't know of a way to easily estimate whether it's really possible. Intuitively, I doubt it. --Anonymous, on Earth, 23:08 UTC, April 4, 2008.

Hi. Well, I didn't see much twinkling in the object or the other stars, either. Also, I watched the object for approximately 30 seconds, although I didn't time it, and also didn't notice any obvious change in brightness, but about 30 seconds or more after, it either dissapeared or faded in brightness. Could it be a flare from a geostationary sattelite, and if so, is there a place that predicts these? I think there is the possibility it may have been tinted a colour, although I'm not sure what colour. Also, do high-orbit satellites' flares last longer? Thanks. ~AH1^(TCU) 20:46, 4 April 2008 (UTC)

Geostationary satellites orbit above the equator, is that consistent with your sighting? Here is a NASA tracker, I haven't played with it. Franamax (talk) 21:51, 4 April 2008 (UTC)

Where was the Jules Verne ATV at the time, and did it have a blinking light? It was recently in space on its way to automatically docking with the ISS. Edison (talk) 00:54, 5 April 2008 (UTC)

Hi. I can't use Heavens-above right now to search for it, but I remembered looking at the list yesterday, and I think ATV was in it. I don't know how accurate it was as the ATV is a craft that changes orbit. However, the first time I checked, which was about 12 hours after the sighting, the Lacrosse 5 was the only satellite on the list crossing the area, and the exact area where I observed it, but the velocity seemed off. I didn't check the ATV's angular velocity, but I think it did go across the northern area, and was visible within the time indicated. Was the ATV a slow mover? However, although the prediction could have been off, I think it predicted to have been in Draco or Leo or Cassiopeia or something, I don't remember. Also, I checked the object for any movement, change of brightness, or blinking. I didn't notice any obvious movement or blinking, although there would have to have been a change in brightness as it dissapeared shortly after the observation. Thanks. ~AH1^(TCU) 01:34, 5 April 2008 (UTC)

If it "was not a satellite", it was not the ATV. The ATV is in a lower orbit than Lacrosse 5, so its angular velocity is larger. The object was too far north to be a geostationary satellite (they appear south of the celestial equator on the northern hemisphere). Icek (talk) 13:44, 7 April 2008 (UTC)

<off topic>In the manga Fist of the North Star, seeing an extra star in the Big Dipper was a sign that you were about to die...</off topic> --Kjoonlee 09:13, 6 April 2008 (UTC)

seawater and human skin

What is the effect of seawater on human skin? Can it cure acne, helpus keep it clean, young ? Mr.K. (talk) 23:41, 3 April 2008 (UTC)

It's not so useful for cleaning, because you smell like dead fish when you're done with your bath. In places where fresh water is in short supply and sea water is plentiful, they will bathe in sea water and then rinse in fresh water, however. Saltwater will tend to dry out the skin, which is somewhat helpful for oily skin. With dry skin, on the other hand, you would need to moisturize after. I don't see sea water as a fountain of youth. On the contrary, if you bathe in it in the sun, the UV damage may age your skin prematurely, especially the parts that stick out of the water, like your face and shoulders. StuRat (talk) 07:10, 4 April 2008 (UTC)

But, if seawater is full of bacteriophages that will be a treatment against acne, right?Mr.K. (talk) 07:31, 4 April 2008 (UTC)

Phages in seawater would tend to evolve to infect the bacteria present in seawater, they wouldn't necessarily be adapted to the bacteria that contribute to acne. However the mineral content of seawater might act as a good solvent to clear the pores of sebum, and the salt content might tend to be toxic to bacteria. Franamax (talk) 08:18, 4 April 2008 (UTC)

Allegedly, special soaps are required when you bathe in salty water, lest no soapy foam be generated. A sailing magazine, shop, or website may have more information.

Atlant (talk) 11:46, 4 April 2008 (UTC)

I've had good experiences bathing in seawater. I suggest you try it and see for yourself. Vranak (talk) 19:49, 4 April 2008 (UTC)

April 4

the earth ; a superconductor ?

soil is conductor to electricity. and as we know as the volume of conductor increases it's resistance decreases. the earth is huge in size and contain lot of soil(which is conductor). so theoriticaly the electrical resistance of the earth should be near to zero. is the earth a super conductor ? —Preceding unsigned comment added by Shamiul (talk • contribs) 06:30, 4 April 2008 (UTC)

No. It would have to be one continuous conductor for that logic to apply. There are many insulating materials, such as air pockets, in the soil, each of which will increase the resistance. StuRat (talk) 07:13, 4 April 2008 (UTC)

what's the conductance of the earth ? is the a earth a better conductor than copper wire ? —Preceding unsigned comment added by 117.18.224.173 (talk) 07:45, 4 April 2008 (UTC)

No, the Earth is a poor conductor. The law that "as the volume [actually cross-sectional area] of conductor increases it's resistance decreases" is only approximately correct for long, thin wires. If the length of the wire is short in comparison with its thickness, the law stops working. The Earth is practically a sphere, not a wire at all, so the law is meaningless when applied to the Earth. If I drive two big metal spikes into the ground, one here and the other a mile away, the resistance between them will be very high. If one of the spikes is halfway around the world, there will be no measurable signal at all (at least for DC; maybe for ELF waves you could see something, but it would be quite difficult). —Keenan Pepper 13:58, 4 April 2008 (UTC)

If the Earth wasn't a good conducter of electricity, it wouldn't work as a ground. Although the Earth isn't a wire, the size of it makes resistance largely based on the size of the electrodes, rather than the distance between them. — DanielLC 15:44, 4 April 2008 (UTC)

DanielLC is right. The local conditions dominate the resistance between two buried electrodes. The earth resistance can be modelled as a set of concentric shells around each electrode. The inner shells have a small surface area, so they need to have a low resistivity in order to produce a low total resistance. This is why it matters where you bury the electrode. Beyond a certain distance, called the 'sphere of influence' of the electrode, the shells have such a huge surface area that even poorly conducting soil has a low resistance when summed over the shells' area. That means that if you planted two electrodes on opposite sides of the Earth, you would get pretty much the same resistance, for a given soil type, as if you planted them a hundred yards apart. The Earth is indeed used as a return conductor in some power transmission applications, but it's risky because you can set up unwanted voltage differences in the ground.

Anyway, returning to the question, it doesn't matter how big the Earth is or how big the electrodes are, the planet isn't a superconductor because it isn't made of superconducting materials. Superconductors conduct electricity in a qualitatively different way from normal conductors. You can make the resistance of a conductor arbitrarily small by enlarging the conductor, but you can't make the resistance exactly zero: only superconductors have that property. --Heron (talk) 18:54, 4 April 2008 (UTC)

As far as not being made of superconducting materials, I have to disagree. All we've got to do is cool the place down to a few Kelvin and apply a few MBar of pressure and there's enough in the crust that it just might work. Shame we wont be around to see that Furmanj (talk) 10:00, 5 April 2008 (UTC)

Good answer, Heron. It does depend mainly on the quality of the electrodes. I take back part of my answer, which was misleading if not wrong. —Keenan Pepper 05:14, 5 April 2008 (UTC)

"The earth resistance to the current, compared with that of a long line, is next to nothing," [13] per Chambers's Encyclopedia,(1883) p438. The resistance is basically that of the grounding electrodes, so that a large and deep electrode, or multiple long ground rods in parallel, or one consisting of the water mains of the town lowers the resistance between the ends of the circuit far lower than any practical metallic conductor connecting two distant points. The earth is not a superconductor, but with its numerous parallel conduction paths it can be a very good conductor for the earth return used with long metallic single conductor circuits. Edison (talk) 00:47, 5 April 2008 (UTC)

rube goldberg machine

I'm going to be building a Rube Goldberg machine. The chain will be initiated by a falling domino and the 'objective' of the machine is to have a marble hit a domino at the end of the whole process. Can anyone give me some ideas on what to build? --hello, i'm a member | talk to me! 06:34, 4 April 2008 (UTC)

The simplest design might be to have a row of dominoes hit a marble hanging on a string which then strikes the last domino. Add complexity from there. StuRat (talk) 07:19, 4 April 2008 (UTC)

At one stage you could whisk aside a curtain to reveal a picture of Hillary Clinton taking the oath of office, which scares a Tasmanian devil so badly that it runs down a plexiglass pipe to the other end of a seesaw. --Milkbreath (talk) 10:23, 4 April 2008 (UTC)

Use a metal domino to make an electrical connection and start a motor? 81.174.226.229 (talk) 10:41, 4 April 2008 (UTC)

My suggestion is to look at the sorts of things that other people have built, and take inspiration from there. I believe that there are a number of Rube Goldberg competitions, some of which get very "creative". You can also alway find examples on video sharing sites (YouTube, Google Video, etc.) -- 128.104.112.85 (talk) 15:48, 4 April 2008 (UTC)

Papadums

When I cook commercially made papadums in the microwave, it takes 30 seconds for three, 40 seconds for four. But if I put one in, it needs 15 seconds. What's the reason? Julia Rossi (talk) 07:39, 4 April 2008 (UTC)

Perhaps something else (the glass plate or whatever container is in the microwave) is heating up as well. Or it could be rounding error. – b_jonas 09:05, 4 April 2008 (UTC)

The magnetron that is the heart of the microwave oven is a vacuum tube and like most vacuum tubes, it includes a heater that must heat up before thermionic emission of electrons can begin inside that vacuum tube. This takes several seconds. So during those first few seconds while the heater itself is warming up, electrons aren't flowing in the magnetron tube so no microwaves are being generated so the oven isn't doing any cooking. If you listen carefully as the microwave oven starts operating, you'll often be able to hear its sound change as the heater reaches operating temperature. Because it is only at this point that the microwave oven starts drawing a lot of power from the power line (mains), you may hear:

• The hum of the oven increase

• The cooling fan, stirring fan, or turntable motor slow down a little

The famous "incinerate a CD" experiment will provide a very-dramatic exhibition of this effect.

Atlant (talk) 11:40, 4 April 2008 (UTC)

Proventil

DOes the effectiveness of Proventil decrease over time? I've read the article, and I couldn't find anything there.--AtTheAbyss (talk) 12:13, 4 April 2008 (UTC)

Proventil is a Beta₂ adrenergic agonist. It is not a class of drugs considered to be resistance-building in the human body. However, there are concerns with long-term use in asthmatics, a fear that they may make asthma uncontrolled. A quick Google search on Beta 2-adrenergic agonists "long-term use" will surely turn up a few studies on the subject. -- kainaw™ 15:28, 4 April 2008 (UTC)

Humans surviving in space

Can humans survive in an area of space where we se massive amounts of dust forming new suns?

As long as they're not too close to one of the stars and in a space-suit or ship, then I'd expect so. I think gamma ray and x-ray bursts occur when stars die, not when they form, so that should be OK. You wouldn't want to be moving too fast relative to the dust, or that could damage the space-suit or ship, which would be needed to provide air, water, food, and regulate the temperature. Although, for temp, you could probably find an ideal location where light from the star(s) would provide just the proper amount of heat, but you'd still need to distribute the heat from the part facing the star(s). StuRat (talk) 14:13, 4 April 2008 (UTC)

The most massive stars have short lifetimes (on the order of 1–10 million years), and so may die while the star-forming region is still active. -- Coneslayer (talk) 14:29, 4 April 2008 (UTC)

Finding out who cited a journal article

I have a journal article: [14] and I am interested in which other journal articles have cites this one. How is it possible to check? --Seans Potato Business 15:08, 4 April 2008 (UTC)

Thomson Scientific's Web of Knowledge product has the ability to do citation searches in both directions. It is a commercial service, however, so you will likely have to find a university which has a subscription. -- 128.104.112.85 (talk) 15:41, 4 April 2008 (UTC)

Google Scholar offers a list of citations. For this article, check [15]. Unfortunately, no citation is listed so far. This is not too surprising for a 2007 article, though. --Stephan Schulz (talk) 15:45, 4 April 2008 (UTC)

Thank you both. :) --Seans Potato Business 17:13, 4 April 2008 (UTC)

A competitor to Web of Knowledge is Scopus which offers a similar service (with subscription). ike9898 (talk) 19:03, 4 April 2008 (UTC)

Where can I get heavy water?

After reading the article about heavy water, I was intrigued and would like to do a photography shoot of heavy ice cubes that sink, not float, in water. But where can I get heavy water? Is it available for sale somewhere? JIP | Talk 15:27, 4 April 2008 (UTC)

It should be available from most places which sell isotopic materials to scientific researchers. For example Sigma Aldrich sells it (as deuterium oxide) for about $1/mL (Enough water to get a couple of ice cubes should cost you under a hundred bucks). Be advised, however, that due to it's potential use for nuclear purposes, there may be (I can't say for certain) extra regulatory hurdles to jump through before they will sell it to an average person off the street. -- 128.104.112.85 (talk) 15:37, 4 April 2008 (UTC)

You'd need tons of the stuff to use it for real nuclear purposes. Not to mention a few other things as well. I'm pretty sure that in the amounts he is talking about there are not even export restrictions. --Captain Ref Desk (talk) 14:44, 6 April 2008 (UTC)

(ec) You can order it from just about any large chemical supply house. Sigma-Aldrich sells 99% pure deuterium oxide for about one U.S. dollar per gram (plus shipping). I don't know if it's possible to have chemicals – even harmless ones like heavy water – delivered to a residential address; you may need to have it delivered to your workplace, or even have a friend in a chemistry or biology lab buy it for you. For what it's worth, you don't need to worry about any nuclear safety regulations; it's non-radioactive and not regulated in any special way. TenOfAllTrades(talk) 15:43, 4 April 2008 (UTC)

$1/mL seems like a high price to pay for 99% pure deuterium oxide. United Nuclear offers 20 mL of Ultrex grade, 99.999% pure heavy water for $17. There's nothing to indicate that they don't ship to individuals, so the same should be true for other chemical dealers. Obviously try to find a local store to avoid paying shipping and handling costs, but the price should be less than $1/mL for 99% pure heavy water. --Bowlhover (talk) 00:36, 5 April 2008 (UTC)

Actually, that United Nuclear product is 20 grams, which is only 18 ml. Remember, this is heavy water... --169.230.94.28 (talk) 02:02, 5 April 2008 (UTC)

Sorry, I misremembered the page and thought it used mL. Since the Sigma-Aldrich price was cited in dollars per gram, however, the conclusion of my post is still true. --Bowlhover (talk) 02:40, 5 April 2008 (UTC)

If you manage it, I'll be interested too see what it looks like! Perhaps you can take a shot for the heavy water article? ----Seans Potato Business 17:05, 4 April 2008 (UTC)

And don't forget to do the opposite too: a chunk of normal ice or some other almost-as-dense-as-water object floating in normal water, and then the same object floating in heavy water. --Anonymous, 22:07 UTC [Insert joke here about daylight saving being "heavy time"], April 4, 2008.

They made tons of it at Norsk Hydro for the Nazis, under the direction of Dr. Seuss. But there were some problems with production and shipping. In 2005 a drum of it was found at the bottom of Lake Tinnsjå. Might look there.Edison (talk) 00:10, 5 April 2008 (UTC)

A sunken ice cube image from the site that Bowlhover cites above. --hydnjo talk 03:56, 5 April 2008 (UTC)

United Nuclear doesn't sell outside Merka. I'll try my chances at Sigma Alrdich though, as they already seem to have sales offices in Finland. For $100, I could get apparently get a whole decilitre of heavy water, which would make for many heavy ice cubes. I'm already starting to design pictures of cocktails with the ice at the bottom of the glass, not at the top. JIP | Talk 18:41, 6 April 2008 (UTC)

Lighting in photographs

Is it possible to describe the lighting observable here and here? What are it's features and does the technique, if any applies, have a name? ----Seans Potato Business 17:23, 4 April 2008 (UTC)

The first image is an example of backlighting: two colored lights behind a set of test tubes filled with water. The second image (the computer keyboard) is probably lit by two diffuse light sources (umbrella reflectors or similar): a blue light above the object, and a yellow light to the left. --Carnildo (talk) 20:38, 4 April 2008 (UTC)

electrical coil

What effect does the diameter of the coil have on its electrical characteristics? 71.100.173.69 (talk) 18:39, 4 April 2008 (UTC)

Inductance#Inductance_of_simple_electrical_circuits. Detailed explanations appear below the graphs, and read the article proper for information on inductance itself. Someguy1221 (talk) 18:53, 4 April 2008 (UTC)

April 5

Hawking's Fact or Theory ?

I'm in the UK and while watching a recent documentary regarding Steven Hawking and the latest 'string theories' my partner asked me a simple question and I was stumped. My partner is in no way a scientist and questioned, 'So is this fact or just what people think?'. Can any model of the universe be proven as factual or is it just mathematical modelling? This question may seem silly to the scientists out there but I regret I am not one of them. I teach six year olds! Thank you for your wisdom! Kirk UK —Preceding unsigned comment added by 88.144.9.132 (talk) 00:09, 5 April 2008 (UTC)

It's a theory. Mind you, that doesn't mean it should be dismissed easily. Theories have been tested and found to accurately model what we know of the universe, and Hawking's theories are no exception. String theory on the other hand is mostly just a mathematical model. The term "theory" is more of a cultural attachment than a scientific appellation, because string theory requires some rather wonky things to be true for it to work. And we don't have the capacity to test those things right now, so it's more of a "string hypothesis." It's mathematically sound, but not necessarily accurate. -- Kesh (talk) 01:33, 5 April 2008 (UTC)

The easiest way to think of the difference between facts and theories is that facts are simple bits of data about the natural world, whereas theories are explanations about the natural world. An example: it is easily observable that a ball dropped from your hand on Earth will fall towards the ground. This is a fact. The reason for this is the theory. Isaac Newton would have said that the mass of the Earth itself exerted a force on the ball, pulling it to the ground. Albert Einstein, by contrast, said that the mass of the Earth deformed spacetime in such a way that towards its center was the path of least resistance for the ball. Two very different explanations of the same phenomena; two very different theories.

Any model of the universe will be a theory by definition. It is a model. It is not the sort of thing that is a "fact", a small piece of data. This is not a problem. Facts are not "proven" theories, facts and theories are two totally different categories of information.

Einstein's Special and General Relativity are both theories. Newton's theory of gravitation is, as the name implies, a theory. Darwin's idea of natural selection as the engine of evolution is a theory.

Is String Theory a theory? Well, it wants to be a theory. Is it really one? Scientists and philosophers disagree. Some don't even think it is a theory because there isn't any way it can currently be proven incorrect. If an explanation about the natural world cannot be tested—proven right or wrong—then it is not a scientific theory. For example, instead of Newton or Einstein's theories I could just as easily say that my theory of why the ball falls is because there are invisible, intangible fairies who carry the ball to the ground. It's a theory that perfectly accounts for any phenomena that one might see. But that's the problem: you can't do anything to test it, you can't possibly prove it wrong. As such, you cannot distinguish between my theory and Newton's theories when it comes to which is more correct. So this is not science. You can distinguish between Einstein's and Newton's theories—they give different experimental and observations predictions in some cases, and indeed it turns out that Einstein's theories perform better than Newton's.

So anyway, back to String Theory. It's very dubious whether it can be truly tested at the moment. At the moment we have no way of distinguishing between a universe run by String Theory and a universe run by the Standard Model of physics. Someday fairly soon we will be able to test some aspects of some variations of String Theory, but even if those tests come back negative they won't really distinguish between String Theory itself and anything other than String Theory. There are some highly imaginative experiments with tools we do not have and may never have that could test String Theory, but given that they are not real options it's not clear that they count towards the philosophical question. Anyway, it's an active question.

Sorry to lecture; your question seemed to me to have two questions in it (what is the difference between fact and theory, and is String Theory a theory). I tried to be clear but not condescending, maybe I have been successful, maybe not... --Captain Ref Desk (talk) 01:58, 5 April 2008 (UTC)

A very complete answer. You might like to read the article on Karl Popper. William Avery (talk) 09:08, 5 April 2008 (UTC)

Also, I suppose you know the String theory strip from xkcd. – b_jonas 18:44, 6 April 2008 (UTC)

Train Washing Machines

Hello all. I am looking for a site which has detailed descriptions of new(est) technology in the field of recycling the water used by train washing machines. I have looked, but been unable to find anything useful. Thanks in advance for any help.

Cuban Cigar (talk) 03:04, 5 April 2008 (UTC)

Are you sure that trains actually have washing machines ? I would think that the expense of hauling around the washing machines, dryers, and water would be prohibitive. For things like towels and bedding on sleeper trains, they could instead drop off dirty laundry and pick up clean laundry at each station. That's how I'd do it if I ran a passenger railroad. StuRat (talk) 13:52, 5 April 2008 (UTC)

Perhaps the questioner is referring to machines which wash the train [16] [17] Think outside the box 14:52, 5 April 2008 (UTC)

Hmm, that could very well be what they meant. StuRat (talk) 04:46, 6 April 2008 (UTC)

If so, have a look at this. It's about vehicles in general, but should be adequate. —Preceding unsigned comment added by D0762 (talk • contribs) 15:51, 6 April 2008 (UTC)

Gauge to track relative movement

Does anyone know a name for the type of gauge shown in this image? Do we have an article on it?

The device is intended to track the relative movement of two objects (in this cases, two parts of a wall that has split apart). I think most of us who live in earthquake zones have seen a few of these; I imagine that they must also be used for buildings that are settling unevenly in other contexts as well.

Feel more than free to edit the description on Commons and add any appropriate categories: this is one of those cases where having snapped the photo does not mean I know a lot about the topic at hand. - Jmabel | Talk 05:08, 5 April 2008 (UTC)

I've seen it called a crack gauge or crack width gauge, and I'm shocked to see that we don't have an article on it yet (as of the following timestamp). --Heron (talk) 09:19, 5 April 2008 (UTC)

That sounds more like something which might be used by plumbers. :-) StuRat (talk) 02:25, 6 April 2008 (UTC)

It's a mechanical strain gauge, like the one shown here. Gandalf61 (talk) 12:58, 5 April 2008 (UTC)

They are all over downtown Charleston. The engineers and insurance companies properly call them strain gauges. -- kainaw™ 17:59, 5 April 2008 (UTC)

Admittedly I only know what I can find on the web, but everybody seems to call them crack gauges, tell-tales or something similar: [18] [19] [20] [21] [22] [23]. There is exactly one example of the name "mechanical strain gauge" being applied to the thing we are talking about, and that's on Wikipedia. Everywhere else, the latter term seems to mean either a linear displacement gauge with a dial or a penis-measuring device. --Heron (talk) 10:28, 6 April 2008 (UTC)

I would object to calling it a "strain gauge" as 1) that's a well-defined term for an electrical sensor and 2) the gadget in the picture isn't measuring strain; once the object under test cracks, there's no strain left, just a variable displacement.

Atlant (talk) 15:50, 6 April 2008 (UTC)

They measure strain on a foundation as a crack widens. I have always assumed that is why the insurance paperwork refers to it as a strain gauge. It could simply be that they don't want to use common terminology because legal paperwork is specifically designed to be unreadable for those who aren't "in the know." -- kainaw™ 23:59, 6 April 2008 (UTC)

Sifting flour

A British recipe for pancake (thin compared to the American variety) calls for me to sift the flour to "air" it. Later, it has me stirring in eggs, milk and water. Is there going to be any of the original air left after all that whisking? Will the air-content of the batter be any different depending on whether or not the flour is sifted? Wont the liquid displace any pockets of air between the flour grains? ----Seans Potato Business 15:41, 5 April 2008 (UTC)

Sifting of flour is superfluous with modern, high-quality flour stored properly. Originally, sifting was used to get out all kinds of undesirable stuff, and to break up clumps sticking together due to humidity. Just use flour out of the package, unless you like the ritual (it makes a nice, even mound of flour ;-). Be aware that most European flour is plain, i.e. not self-raising. Self-raising flour will make very different pancakes (though they can be nice as well, of course). --Stephan Schulz (talk) 16:43, 5 April 2008 (UTC)

Sifted flour will be slightly less dense, which matters in the U.S. where people measure out so many "cups" (8 fluid ounces) of flour. It would make little difference in the rest of the world where people measure so many grams of flour. Edison (talk) 19:34, 5 April 2008 (UTC)

Most American flour is also non-self-rising. I think self-rising flour is only common in the South, where it is used for biscuits. -- Coneslayer (talk) 19:36, 5 April 2008 (UTC)

Also, just because flour starts out lump-free at the factory doesn't mean it always stays that way. It could get a few drops of water in it that form lumps (say if the scoop used to get the flour was just washed). Or, even worse, it could have bugs in it (living or dead). I'd rather find this out when sifting than when I bite into one. StuRat (talk) 01:50, 6 April 2008 (UTC)

A useful pancake tip: If you want light, fluffy pancakes and the recipe calls for water, use seltzer instead. The carbon dioxide in the seltzer will come out of solution and make for lots of tiny gas bubbles in your batter.

Atlant (talk) 15:46, 6 April 2008 (UTC)

Blood vessel cells

Not a homework question; do the cells of the blood vessels obtain oxygen and nutrients from the blood the vessels are carrying or do the veins and arteries have their own circulatory system as the heart does?--TrogWoolley (talk) 21:34, 5 April 2008 (UTC)

See Vasa vasorum. --Arcadian (talk) 01:40, 6 April 2008 (UTC)

April 6

How to make a flaming drink

I am in a play "The Farmer's Daughter." In the show, a girl makes a drink called Glug. Before giving it to me she pulls a fireplace poker out of the fireplace, and puts it in the drink.

In the movie, the drink flames and goes out. That would be a pretty neat trick. Does anyone know how we could pull this off? Keep in mind there is no fire in the stage fireplace and I have to be able to drink this beverage.

If you'd like to see the flaming drink in the movie trailer, it shown on the bottom of the page I have for the show.
http://wonderley.com/shows/2008/FarmersDaughter
--Wonderley (talk) 01:48, 6 April 2008 (UTC)

For the drink, water with a little bit of pure (or 80%) ethyl alcohol very carefully poured on top might do it. If the alcohol is warmer, it might lie on top of the water for a while before mixing. To get the fire, hide an electric sparker in the tip of the poker and a trigger in the handle of the poker. Have a stagehand with fire extinguisher ready and waiting if you try this live or in rehearsal and make sure your costume isn't flammable. Franamax (talk) 02:09, 6 April 2008 (UTC)

Flaming liquids sound rather dangerous to me, both to the actors and the audience if it starts a general fire. Perhaps some type of lighter, set on high, hidden on the far side of the glass, could create enough of a flame without being so risky. StuRat (talk) 02:23, 6 April 2008 (UTC)

Flash paper in the glass and a burning incense or punk stick on the far side of the poker should do it. --hydnjo talk 03:01, 6 April 2008 (UTC)

Whatever you do, the key word here is safety, safety, safety. Applause happens once, burn scars are forever, fire deaths last longer. From the video clip (which we all assume you obtained copyright release for): watch the actress hand, her grip is curious; she dips deliberately into the cup as if to contact something, then pulls back a little, then removes the poker; the cup is opaque; the scene ends, as all movie scenes do. No way to tell what happened there, I'd guess a pilot light in the cup, she pushed a trigger to open the main gas line, then the key grip guy shut the gas off. Did the drinker actually drink anything? Did the cup get subbed in for the next take? There could be a whole lot missing where the entire set went up in flames. Safety, safety, safety. Franamax (talk) 07:26, 6 April 2008 (UTC)

Not wishing to pour water on your special effects but are your insurance company happy with this? Richard Avery (talk) 10:17, 6 April 2008 (UTC)

Any "high-proof" liquor will burn (because of the included ethanol). The problem is that the alcohol fire is practically invisible under the stage lights. You might find that doping the drink with table salt (sodium chloride) will produce visible flames. That's basically what I did once when a production needed two flaming brazier-style lights (although I used straight alcohol, probably methanol). Today, though, I'd probably fake it with streamers, fans, and lights (for reasons of safety). Heck, if it only has to flame for a few seconds, you could probably design that same streamers/lights/fan mechanism into a cup and power it with NiCd batteries; LEDs can be very bright with very little power and a brushless DC computer fan draws almost no power either.

Atlant (talk) 15:41, 6 April 2008 (UTC)

!!If you are going to drink it, DO NOT use methanol (or anything else with a skull on the bottle). Franamax (talk) 19:44, 6 April 2008 (UTC)

It should be clear by now that this was not an appropriate question for the Reference Desk: if you're going to have a fire on the stage, you'll need a professional stage effects person, and not advice from random people at Wikipedia. --Anonymous, 20:56 UTC, April 6, 2008.

Anonymous, if I got bad advice, I wouldn't use it. Flaming drinks and food are not uncommon. I was just getting ideas that maybe I had not thought of for the drink and the ignition source. Suggestions like adding table salt to make the flame more visible makes the stunt safer. Not drinking beverages with a skull on the bottle's a pretty good idea too. ;-) So, it seems pretty appropriate to me. But thanks for your concern.

Franamax, I didn't exactly obtain a copyright release, but the trailer on the TCM web site has a "Embed this video on your site" button, so I assumed it was OK.--Wonderley (talk) 23:33, 6 April 2008 (UTC)

The wag in willy wagtail

The article wagtail doesn't explain the mechanics of the little bird's movement style. What makes it wag when it moves? Julia Rossi (talk) 03:16, 6 April 2008 (UTC)

It's voluntary, the way a dog wagging its tail is voluntary, though for a different purpose. kwami (talk) 03:35, 6 April 2008 (UTC)

Is it a space or warning thing? Like to make the little bird seem bigger to intruders? Julia Rossi (talk) 04:15, 6 April 2008 (UTC)

I don't know, but it seems to me that for the East African sp. it is some kind of communication. They do it with each other, and they do it when not on their home territory. kwami (talk) 04:43, 6 April 2008 (UTC)

Thank you Kwami, it makes sense - just that it's seems unusual for a bird to flutter and wag constantly, though it is low-key. And strange that the article doesn't comment on it's namesake feature. Julia Rossi (talk) 08:56, 6 April 2008 (UTC)

mental capacity

Is there a test which rates mental capacity on the basis of reducing to minimum form a logical equation having a certain number variables and states? 71.100.173.69 (talk) 06:54, 6 April 2008 (UTC)

No. Tests for mental capacity are designed so that they can filter out something like "innate capabilities" from "learned abilities". In your example, a genius who has never taken algebra would probably rate as a dullard based on lack of experience with the formalities alone. --Captain Ref Desk (talk) 14:30, 6 April 2008 (UTC)

Hair

What are the usual age ranges for men and women to begin a) getting grey hair? b) losing their hair? Thanks 92.5.114.92 (talk) 10:06, 6 April 2008 (UTC)

See a) Effects of aging on hair color and b) baldness D0762 (talk) 15:43, 6 April 2008 (UTC)

Where does the fat from skimmed milk and low-fat yogurt or cheese go?

There must be lots of it, how is it then used please? I cannot believe it is just dumped somewhere. Thanks 80.0.106.237 (talk) 19:41, 6 April 2008 (UTC)

• cream, butter, ghee are all possible uses. Graeme Bartlett (talk) 21:21, 6 April 2008 (UTC)

Future costs of photoelectric cells?

Will photoelectric cells become cheap enough to cover the walls and roof of my house with, or will the price always be high because they contain some rare element? 80.0.106.237 (talk) 19:44, 6 April 2008 (UTC)

They don't contain any 'rare' elements, per se... the silicon that is used in the majority of terrestrial solar panels can be found in sand. However, there are huge energy and cost barriers needed for processing pure silicon and making solar panels. The energy cost takes about twelve years of average use to recoup. As for cost, I estimated that it would take me ~30 years to recover the costs of installing solar panels on the roof of my house. This may be different depending on where you live (I'm from Rhode Island... sun can be limited in the winter). I know that in California they are topping a lot of department stores with panels to combat peak energy-use times (such as the summer). I also think the technology is improving every day, so solar panel housing may not be far off! --138.29.50.28 (talk) 23:25, 6 April 2008 (UTC)

How small can computers get in the future?

I've decided to ask this here rather on the Computing Desk as it is more about physics than software. Soon, I hope, computers will be able to use human speech as their input and output, doing away with keyboards and screens for some applications. Will it then ever be possible to have computers, with the equivalent power of a laptop, that are small enough to fit on a keyring? And how small could the talking thinking computers of SF films be in actuality in the future? I'm thinking about the limits to the smallness of microchips, and would quantum computing be smaller? Thanks 80.0.106.237 (talk) 20:02, 6 April 2008 (UTC)

• We can already make a computer that is as capable as a laptop but that will fit on a keyring. (cell phone)
• We have had competent speech recognition on home computers for fifteen years
• We have had speech output for longer that that
• The theoretical limit on information storage is the Bekenstein bound. We are many orders of magnitude away from it
• The "practical limit" of achievable size reduction and speed increase is ten years in the future, or appoximately a 32-fold improvement from our existing capability. This has been true since 1950. In 1950, the limit was to be reached in 1960. In 2008 the limit is to be reached in 2018.... See technological singularity.

-Arch dude (talk) 22:28, 6 April 2008 (UTC)

I think I'll stay with the keyboard regardless. It's a faster way to input (when you know how to type) than speech, and nobody has to know what I'm doing. And it's bad enough that people blab on and on to their cell phones in coffee shops—imagine if they were all blabbing to their computers (and their computers blabbed back)!

In any case, note that you don't necessarily need to miniaturize everything. If you came up with fast, secure, and cheap wireless interfaces, you could have a tiny thing in your ear that just interfaced with the central computer. It becomes a communications issue, not a processing one. This is featured in many SF movies and books, too (the second book of the Ender's Game series comes to mind). --Captain Ref Desk (talk) 23:53, 6 April 2008 (UTC)

I agree, the noise pollution is bad enough without banality pollution as well. Julia Rossi (talk) 01:22, 7 April 2008 (UTC)

Computers will get smaller, faster, and more capable as they become more refined to specific purposes. Similar to object-oriented software design, computers will begin to take on specific tasks while communicating with one another. Why have a clock in your cell phone when your watch does that job just as well? Why have a camera lens in your phone when it can be in your glasses, already pointed at what you want to photograph? Why have a phone in your pocket and a earbud on your ear when the earbud can handle all the call-placing tasks itself? In the future, we'll wear a network of mini-computers without thinking of them as anything more than helpful gadgets. The idea of a computer that does a million different tasks will be abandoned for the average person. In fact, many people don't like them already. -- kainaw™ 01:45, 7 April 2008 (UTC)

Helium filled football

I am doing a science project about whether a helium filled football or an air filled football can be thrown further. Do you know how or where I can go to get helium inside of a football?70.18.162.125 (talk) 20:22, 6 April 2008 (UTC)CD

I'd start with party-supplies places. If they can inflate a balloon with helium, they may be willing and able to inflate a football. I say "may be able" because I don't know if there will be problems connecting a football to the tank.

Some issues:

• The gas used in party supplies may not be pure helium. It only has to be light enough to make a balloon rise, and diluting it with a heavier gas light nitrogen may make it cheaper.
• Helium leaks out of things faster than air does, because the atoms are so small. So you'll want to take the football directly from the place where you get it filled to the place where you want to throw it.
• I would expect the difference will be too small to be meaningful. (Even if so, that doesn't mean the project is a bad idea! If you prove there's no significant difference, you've still proved something.) A well-designed experiment would involve plenty of throws with each ball, and statistical analysis such as a chi-squared test to determine whether the differences are significant.
• If the same person is throwing the ball several times, they will get tired, or they will first get more warmed up, and then get tired. So you don't want to do something like 5 throws with air followed by 5 with helium. Use an alternating pattern or something like ((air, helium, helium, air), repeat as many times as desired).
• For the same sort of reasons, if different people are throwing the ball, have half of them do air first and half do helium first.

Have fun. --Anonymous, breathing air, 21:11 UTC, April 6, 2008.

• I would suggest that you will not notice the difference. The air in the ball will only weigh about a gram. Graeme Bartlett (talk) 21:25, 6 April 2008 (UTC)

Limb regeneration in Humans

Are there any documented cases of people regenerating limbs (or digits) that they've lost? I know that this is generally impossible, but my impression (IANAD) is that medically impossible things do happen sometimes, and our species certainly has a long history with amputation. 71.239.209.220 (talk) 20:36, 6 April 2008 (UTC)

Our article on Regeneration (biology) has some (imperfect) sections on regeration of human organs and fingertips, the only extremeties observed to regrow. It says what is basically true, that there is evidence children have the capacity to regrow lost fingertips, although there is more or less anecdotal evidence this can occur in adults as well [24]. Someguy1221 (talk) 22:36, 6 April 2008 (UTC)

Homemade Water Filtration?

How can I filter blue food colouring out of water using a homemade filter? I do not have access to activiated charcoal. Are there other materials that are as effective at cleansing water? Thanks, Perfect Proposal ^{Speak Out!} 21:22, 6 April 2008 (UTC)

Can you make charcoal by burning wood or toast. If so you can make activated charcoal. Another way to do it is by fading. Intense focussed sunlight will bleach your blue colour. I am assuming that your blue will not be easy to chemically alter to a clear substance. Indigo can be reduced to white. Some you can bleach with chlorine bleach. Graeme Bartlett (talk) 21:29, 6 April 2008 (UTC)

electromagnetics

A uniform surface charge density of 20nC/m2 is present on the spherical surface r=0.6 cm in free space. a) Find the absolute potential at P(r=1cm, θ=25°, φ=50°). b) Find VA-B (potential difference between point A and point B) given points A(r=2cm, θ=30°, φ=60°) and B(r=3cm, θ=45°, φ=90°). —Preceding unsigned comment added by Yabadapado (talk • contribs) 22:21, 6 April 2008 (UTC)

Welcome to the Wikipedia Reference Desk. Your question appears to be a homework question. I apologize if this is a misevaluation, but it is our policy here to not do people's homework for them, but to merely aid them in doing it themselves. Letting someone else do your homework does not help you learn how to solve such problems. Please attempt to solve the problem yourself first. If you need help with a specific part of your homework, feel free to tell us where you are stuck and ask for help. If you need help grasping the concept of a problem, by all means let us know. Thank you. Someguy1221 (talk) 22:30, 6 April 2008 (UTC)

Plants with not much light

Are there any indoor plants that do well in inner spaces without much light ? (like halls that are a bit dark and gloomy with no window). Thanks for any info. --AlexSuricata (talk) 22:42, 6 April 2008 (UTC)

Depends on the wavelength of the light mostly - This link might be helpful [25]. Wisdom89 _{(T / ^C)} 23:14, 6 April 2008 (UTC)

It's in the link above, but the Aspidistra was a universal parlour and hallway plant in the Victorian era and Edwardian times and possibly the Georgian era before, in very gloomy conditions like terrace housing, so tested, yep. Julia Rossi (talk) 01:13, 7 April 2008 (UTC)

April 7

neighbor's dog and silent whistle

My neighbor has a very annoying dog. Specially when the dog is alone it is very loud. I thought I could buy a dog whistle to 'train' the dog so it can let me alone. As it starts to bark I could blow the whistle as loud as I can. Does this training method will work? 217.168.3.246 (talk) 00:08, 7 April 2008 (UTC)

Galaxies

Hi. Do you know what the farthest galaxy from the Milky Way that we know of is?Thanks! —Preceding unsigned comment added by 208.54.14.121 (talk) 00:24, 7 April 2008 (UTC)

Hi. Well, the farthest galaxies that are visible with any type of telescope are about 13 - 17 billion light-years away. They're in the Hubble Deep Field or maybe the Hubble Ultra Deep Field, if I'm not mistaken. However, the universe is believed to only be about 12 - 15 billion years old, and beyond that boundary, the galaxies' light did not have time to reach us and you're looking at them before they existed. I think some of their distances might be calculated by redshift. Remember there might be galaxies an infinite distance away from us, they're just too far to be in the observable universe from our location. Hope this helps. Thanks. ~AH1^(TCU) 00:48, 7 April 2008 (UTC)

"that we know of" limits this to an answerable question. In 2004, galaxy Abell 1835 IR1916 was discovered to be 13,230 million light-years away. I haven't read about any further ones in the last few years. -- kainaw™ 01:39, 7 April 2008 (UTC)

One possible answer is IOK-1, discovered in April 2006. According to the discussion at Galaxy#Formation, Abell 1835 IR1916 has been claimed to be even more distant than IOK-1, but its distance and nature (is it in fact a galaxy?) are less well characterized. --mglg_(talk) 01:50, 7 April 2008 (UTC)

--172.134.250.18 (talk) 02:24, 7 April 2008 (UTC)

--172.134.250.18 (talk) 02:24, 7 April 2008 (UTC)if i exposes myself to cosmic rays will i get super powers like in the fantastic 4