Wikipedia:Reference desk/Archives/Science/2008 January 23

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January 23

discovery of how to measure blood glucose with a home blood glucose meter

Background: In the 1960-1970's, people with diabetes tested their blood glucose by using their urine and a clinitest pill or Benedict's Solution. This gave the amount of glucose in the urine that could then be related to the amount of glucose in the blood.In the 80's home blood glucose meters came on the market and have evolved to a small, fast meter that provides blood glucose reading in 5 seconds.

Question 1. I have tried to learn the history of the who and how the details to allow a small and inexpensive meter to read the blood glucose in a drop of blood. Please help.

Question 2. Who discovered that glucose actually attachs to the hemoglobin molecule? Based on that knowledge, a person figured out they can determine the average blood glucose level over the past 2-3 months. Do you know who did this? The test is called Hemoglobin A1C. It came about some time in the 1980's. —Preceding unsigned comment added by 69.105.39.67 (talk) 01:32, 23 January 2008 (UTC)

Re question 2. our article on Glycosylated hemoglobin gives some history about the discovery of HbA1c. hydnjo talk 03:16, 23 January 2008 (UTC)

Re question 1. the Glucose meter#History section identifies the patent holding companies. hydnjo talk 03:22, 23 January 2008 (UTC)

Ichthyophobia

I was wonder what i would have to do to get a page for Ichthyophobia the fear of fish. I myself suffer from Ichthyophobia. --Mr. S.C. Shadow (talk) 02:49, 23 January 2008 (UTC)

You would merely need to start one, my friend by simply clickin on this red link Ichthyophobia (putting down what you know- others will do the rest)!--TreeSmiler (talk) 02:56, 23 January 2008 (UTC)

There you go its happened within 2 hours?--TreeSmiler (talk) 04:14, 23 January 2008 (UTC)

Anchoring a Ship

Please explain the working of an Anchor in a Ship. Why is it used for? How many anchors are there in a Ship? Is it capable of keeping the Ship stable in the sea? Please explain in detail. I have searched Wikipedia. But need details. —Preceding unsigned comment added by Ajuputhuvely (talk • contribs) 05:46, 23 January 2008 (UTC)

Well, there are usually two anchors on large (150+ metres) ocean-going cargo vessels - both at the bow of the ship (one port and one starboard). They are usually mighty heavy things attached via large (large large) chains on a motor (to lift the anchor when moving away), the anchor itself can weigh a good few tonnes and be 2-3 metres long. When the ship is to set anchor, one of them (usually one is enough) is lowered (let fall) until it hits the seafloor and buries itself in it a bit (e. g. when waiting before entering a harbour, this place is called a roadstead, the depth is usually not more than a few tens of metres). Usually the anchor is enough to keep the ship fairly stable, although strong winds can move/spin the ship a bit - but it will not move very far. Further from the shore ships don't use anchors when mooring - one reason is that the ocean floor is too far down, the other is that there's almost no difference, because usually (not always - ships cross the sea using specified routes and corridors) there's nothing around to protect the ship from (like land or other ships), and if so - there's always an officer on deck equipped with a radar and various other equipment, and wary of anything and everything happening in a radius of at least a few kilometres. Any questions? --Ouro (blah blah) 10:26, 23 January 2008 (UTC)

Analyzing notation H7h6 and similar notation

Could you guide me as to where can i find information on decoding tolerance codings —Preceding unsigned comment added by 220.227.67.171 (talk) 06:50, 23 January 2008 (UTC)

Could you give us some context here? Tolerance of what, encoded where, etc.? DMacks (talk) 13:48, 23 January 2008 (UTC)

No one answered this yet? Tut, tut reference desk regulars. I think the OP is talking about ANSI standard fits (for screwthreads, shafts etc). All the answers are in this book SpinningSpark 21:37, 25 January 2008 (UTC)

Training my Macaw (reposting because noone replied)

I've seen videos on YouTube of macaws and other parrots rolling over, lying on their backs with their feet in the air, relaxing and allowing their owners to tickle their bellies or play fight with them. How can I train my Hyacinth Macaw to do this too? I've tried to very gently get my hand underneath and flip her over when she's playing on the floor but she absolutely hates it. --62.136.217.51 (talk) 07:34, 23 January 2008 (UTC)

Hello again. I suspect you can't teach an old macaw new tricks. How old is your macaw? For activities that don't come naturally to an animal, it's usual to start getting them used to stuff when they're young, innocent, trusting and obliging – well, up to a point – and used to being handled a lot. And you must be persistent and very, very patient, use rewards and keep the sessions short so they don't get bored/tired. Also it helps to work with the creature's tendencies (example, dogs roll over since that's what they do in submission behaviour which makes it easy). Does your bird allow you to cradle her to allow tickling to start with? Sounds like quite a challenge. Now you need to wait for a bird wrangler to enlighten us all. Anyone? Julia Rossi (talk) 09:30, 23 January 2008 (UTC)

Check out birdchannel.com/bird-behavior-and-training. They don't describe how to train for that particular trick, but they do cover other similar ones. They also have information on handling macaws. They also have a forum where you can ask questions of other bird owners.--Eriastrum (talk) 20:58, 23 January 2008 (UTC)

In the universe, light exists most abundandtly at what wavelength/energy?

I'm not talking about visible light, but the general electromagnetic radiation. 206.240.27.230 (talk) 11:32, 23 January 2008 (UTC)

Cosmic microwave background radiation is the black-body radiation of the big bang. MilesAgain (talk) 13:34, 23 January 2008 (UTC)

Equivalent to the radiation emitted by a black body at a temperature of 3 Kelvins. See black body radiation--TreeSmiler (talk) 15:56, 23 January 2008 (UTC)

...so we know what the microwave end of the cosmic spectrum looks like, and its structure is nice and simple. But adding in all the photons emitted during the history of the universe since then produces a rather more complicated spectrum, which is discussed here and here. Gandalf61 (talk) 16:46, 23 January 2008 (UTC)

...and we even have an article on this - see cosmic latte. Gandalf61 (talk) 12:25, 25 January 2008 (UTC)

physiology

How does the mammalian ear perform its functions?McTut (talk) 11:59, 23 January 2008 (UTC)

Have you checked out our ear article and the links from there? What questions of yours has that left unanswered?

Atlant (talk) 13:16, 23 January 2008 (UTC)

If you could give neutrinos a negative charge...

Then allowed them to pass through matter, would they collide with protons? If so, what would happen? 64.236.121.129 (talk) 14:27, 23 January 2008 (UTC)

That's a question for which you can make up whatever answer you like. The laws of physics, as we know them, don't contemplate a charged neutrino and can't explain or predict the behaviour of one. Neutrinos don't interact by the electromagnetic force (only by the weak nuclear force and through gravity) and so the idea of them carrying a charge is incompatible with their nature.

It's like asking, "If cars could fly, would a car travelling downward or one travelling horizontally have the right of way at an all-way stop?" Our laws of physics – the 'rules of the road' – can't answer a question about a particle that doesn't exist. On the bright side, if you're writing a science fiction story, you can choose whatever answer is most convenient for your plot. TenOfAllTrades(talk) 15:02, 23 January 2008 (UTC)

Please, you can skip the analogy, I get it. I guess I should rephrase the question. The fact is, neutrinos can interact with matter, although not very often. If neutrinos tried to pass through a light-year of lead, they are slowed by about 50% if I'm not mistaken. So a neutrino should strike a particle at some point, although rarely. My question is, what happens when they strike? 64.236.121.129 (talk) 16:51, 23 January 2008 (UTC)

A neutrino with a negative charge would no longer be a neutrino and would definitely no longer pass through matter. It is mostly the neutrinos lack of charge along with its inability to interact with the strong nuclear force which allows it to pass through matter in the first place. SpinningSpark 15:18, 23 January 2008 (UTC)

Ok so it's not a neutrino anymore, if it possessed the same properties as a neutrino and had a magnetic charge, it would collide with particles of opposite charge? Btw what you said along with its low mass is what allows it to pass through matter. 64.236.121.129 (talk) 16:51, 23 January 2008 (UTC)

The problem is this is a hypothetical question. Only hypothetical answers can be given. The truth is no one can answer your question since no one know how a neutrino with negative charge would behave. NYCDA (talk) 18:44, 23 January 2008 (UTC)

Spinning said they would definitely no longer pass through matter. 64.236.121.129 (talk) 18:53, 23 January 2008 (UTC)

I'm going to have to land on the side of "fairly meaningless question", too, I'm afraid. As already noted, you're changing one of the fundamental properties of a neutrino by assuming charge is relevant (as opposed to, say, proton vs neutron). Your best approximation is to say that it would be like an electron (electrons and neutrinos are both leptons), but as our lepton article notes, there's a massive (give or take a factor of 100000) difference in their masses. With such a vanishingly small mass and an electron-sized charge, a charged neutrino's interactions would be completely dominated by the electromagnetic force -- like electrons, only more so. — Lomn 19:46, 23 January 2008 (UTC)

No one called it a fairly meaningless question. I would appreciate it if you kept those comments to yourself. 64.236.121.129 (talk) 19:21, 24 January 2008 (UTC)

I find it a reasonable paraphrase of the thoughts expressed by the other respondants; namely, that there is no meaningful answer to the question. For that matter, that sentiment is more scientifically valuable than the stuff I wrote about leptons, which is really no more than jargonized daydreaming. I would appreciate it if you'd accept that the most appropriate answers to your questions are sometimes the ones you don't want to hear rather than editorializing about them. — Lomn 19:36, 24 January 2008 (UTC)

Those comments can lead to personal attacks. Please refrain from such comments. 64.236.121.129 (talk) 18:08, 25 January 2008 (UTC)

If neutrinos had charge (or if there were elementary particles similar to neutrinos except that they had charge) then the electron could decay into a combination of charged and uncharged neutrinos without violating charge conservation. As the neutrino is so much lighter than the electron, this would be energetically favourable, and the electron would have a very short lifetime - for comparison, the lifetime of a muon, which is about 200 times as massive as an electron, is a few millionths of a second. So all the electrons in the universe would quickly decay into neutrinos. You might have some equivalent of atoms, with charged neutrinos orbiting the nucleus instead of electrons, but I think their chemistry would be very different, as "neutrino-atoms" would be much easier to ionise than "electron-atoms". In short, a universe which contained charged neutrinos would be entirely different from the universe that we know and love. Gandalf61 (talk) 20:02, 24 January 2008 (UTC)

Interesting. Thank you. 64.236.121.129 (talk) 18:13, 25 January 2008 (UTC)

Science and Consciousness

There has been some renewed consideration of the implications of a Boltzmann brain. As it disects the possibilities, this amazing New York Times article offers, "you yourself reading this article are more likely to be some momentary fluctuation in a field of matter and energy out in space than a person with a real past born through billions of years of evolution in an orderly star-spangled cosmos. Your memories and the world you think you see around you are illusions...Nature tends to do what is easiest, from the standpoint of energy and probability. And so these fragments — in particular the brains — would appear far more frequently than real full-fledged universes, or than us. Or they might be us."

The fantastic article (highly recommended) cruises through entropy (open that graphic up!) and offers that the brains are several times even millions of times more likely than a 14-billion year evolved consciousness. My question is: what are the assumptions about the universe (size, expansion etc.) for this to be true? Sappysap (talk) 16:50, 23 January 2008 (UTC)

It looks to me like the universe must have a finite size (rather than expanding forever) for this to be true. Otherwise Boltzmann brains would get less common over time, and the number of Boltzmann brains ever existing would probably be finite. Assuming it is finite, there's nothing preventing it from being far less than the number of evolved brains. Also, the universe must last forever. If there is a Big Crunch, there will be no possibility of Boltzmann brains forming after it. Finally, the law of increasing entropy must hold true. If the Big Bounce theory is correct, it looks like entropy will be reset to zero after every Big Bounce. — Daniel 17:47, 23 January 2008 (UTC)

Sirius

Hi. Is it possible I saw Sirius' companion or perhaps its ghost image? When I look at Sirius through a window that has fog on it with a 114 mm reflector at 36x, I see a point of light, but an extremely elongated one, and sometimes it even look like a line. This is caused by the window because it is fine when I try it on a star outside. Anyway, at 36x I see a ghost image of Sirius to the left of it. When I look closely it looks like there is another faint line-like object to the left of Sirius, touching its elongated disk. When I zoom in to 90x, I think I see a faint object to the right of it, but I couldn't confirm this because clouds covered the scene. When I zoom into 180x, I think I see a faint object to the right of Sirius. To give you a sense of direction, the star drifts from right to left, and it takes four seconds for the entire elongated image to go into view. So, I am measuring in drift-seconds here, the distance a celestial image moves in one second. Note these are not arcseconds. Sirius appears four drift-seconds long and two wide. Just off the centre of the image I see a tiny bright disk. Anyway, the faint starlike image is at the rightmost edge of the squished disk. Sorry I have to go, I'll add more info later. Thanks. ~AH1^(TCU) 18:45, 23 January 2008 (UTC)

Ok, I'm back. So, anyway, the image that appeared to be the companion probably appeared between mag. 7 and mag. 10. It's hard to estimate because I'm basing it on memory and there were no other stars nearby. By the way, when I looked through my telescope at 36x at both Sirius and Procyon, I saw about 15-20 stars through the window, with fog on it, with occasional clouds passing, with atmospheric interference, and with my relatively poor eyesight. I know none of these stars are its companion because they are too far. Is two shift-seconds a bit too far from Sirius to be plausible? I didn't have to use much averted vision to see it, although sometimes I had to shift my eyes to see it, but it was so faint yet clearly visible that it's hard to tell if it's there. So, what do you think? Normally you need 250mm aperture under good conditions to see its companion, but is it possible that I glimpsed it? Or does the main disk point of Sirius, probably about 1/10 shift-second wide, appearing about 1/3 shift-second higher (in the described orientation) than the centre of the elongated disk, indicate the presence of the companion? At which part of the image relative to Sirius A in this orientation should the companion have been? Or are these ghost images and elongations completely caused by the window? Thanks. ~AH1^(TCU) 22:27, 23 January 2008 (UTC)

You're probably seeing an illusion. Window glass is not optically flat, so double images, distorted images, and the like are quite common. --Carnildo (talk) 23:19, 23 January 2008 (UTC)

Uh-huh.

It happens that there's an article about Sirius B in the current (February) issue of Sky & Telescope. Its separation from the primary is currently 8.2 seconds of arc. Dividing by 360/24 = 15, that's 0.55 seconds of time -- so 2 seconds of time, as you ask about, is too much by a factor of about 4. Incidentally, the article contains a specific caution against seeing a ghost image due to reflections in your optical system and thinking it is Sirius B.

--Anonymous, 07:00 UTC, January 24, 2008.

alka seltzer

what kind of gas is produced when you mix Alka-seltzer with water or H20 —Preceding unsigned comment added by 198.203.81.19 (talk) 20:12, 23 January 2008 (UTC)

Alka seltzer#Chemistry of the effervescence. Someguy1221 (talk) 20:19, 23 January 2008 (UTC)

Fever: Better to tough it out or bring it down?

This is not a request for medical advice. It is a theoretical question asked out of curiosity. It's often stated that a fever is part of the body's strategy for fighting off viral or bacterial infection. If that's so, then wouldn't forcing a fever down (as for example by taking acetaminophen/paracetamol) sabotage this fighting mechanism? It seems to me by reducing a fever, one might possibly make oneself feel less miserable for a longer time vs. more miserable for a shorter time (higher fever → greater efficacy in fighting off the infection → shorter illness vs. lower fever → reduced fighting efficacy → longer illness)? Obviously a critically-high fever must be reduced; in asking this question I'm assuming a noncritical fever. --Scheinwerfermann (talk) 22:48, 23 January 2008 (UTC)

Well, this is basically the question between the "Western medical approach" and what might be called the more respectable philosophies at work in some forms of homeopathy (no, I'm not talking about the "dilute things to nothing" aspects of it, I'm talking about the "symptoms are the body's way of fighting disease" aspects that scientists do often take seriously). The question comes in part down to the question of what do people like better—prolonged but lesser agony or short but intense agony. If I'm not mistaken, most people prefer the prolonged but less intense approach, which for the case of the fever would mean pain relief (in keeping with Western medicine), but in the case of some other things, like ripping off bandages, actually goes against the practice in most hospitals (where nurses usually argue for short bursts of pain). --24.147.69.31 (talk) 22:59, 23 January 2008 (UTC)

(edit conflict)Hi. I probably won't be able to answer your question directly, but this seems like a matter of treating the symptoms or helping fight the source of the symptoms. Although treating the symptoms may make you feel better, it doesn't get rid of the actual disease. While a cold may have no known absolutely certain cure, most drugs that seem to help either helps fight off the symptoms, or in the case of antibiotics helps fight off the germs. However, drugs that help fight the symptoms might help a little, so you don't cough so often that you damage your lung-vocal system and end up with a long-term disease. However, when there is both the choice of treating the symptoms and the choice of treating the actual disease, it would probably be better to treat the disease (provided that it actually works). I'm not an exper on this though, and I'm also not giving any medical advice. Hope this helps. Thanks. ~AH1^(TCU) 23:01, 23 January 2008 (UTC)

The problem with this theory is that we've evolved the "raise temperature to kill invaders" approach, but it's quite primitive, and doesn't have a foolproof "but only up to a certain point" mechanism. People can and do get injured by running too high a fever. --Sean 23:41, 23 January 2008 (UTC)

The body can exhibit excessive responses to disease and injury, but I've been unable to find any studies on the dependence of recovery time on the taking of fever-reducing meds. I'm reminded of this question back from december, which is basically ask the same question but with "inflammation" instead of "fever." Someguy1221 (talk) 03:34, 24 January 2008 (UTC)

Further, with some mild illnesses the fever is the most debilitating symptom. Even if a fever did mean that you'd get better in 3 days instead of 4-5 days, you might still prefer the latter course if you knew this was something you'd get better from anyway. --Anonymous, 37°C, 07:02 UTC, January 24, 2008.

There has been some recent research into the purpose and usefulness of fever. One study (news article:[1] - subscription may be required) found that mice with short life spans rely heavily on fever to fight infection, whereas longer-lived mice use a "bed rest" strategy, with little to no induction of fever. The thought is that short-lived animals can't afford to slow down and rest (wastes too much time), whereas longer-lived animals can avoid the collateral damage to their own tissues that fever produces. If we try to translate this to humans (remembering always that mice aren't humans), if you bring down a fever, although you may prolong the time to recovery, you may possibly produce less damage to your own body as a result. I'm not about to speculate what the appropriate damage/time balance is, though. -- 17:37, 24 January 2008 (UTC) —Preceding unsigned comment added by 128.104.112.34 (talk)

It depends on the illness, mainly. Some sexually transmitted diseases like Gonorrhea can be inhibited or destroyed by a heightened temperature, but many viruses actually trigger the hypothalamus in order to raise the temperature to their optimum temperature. Most bacteria and viruses are at least slowed down by a fever, giving the body more time to mount a defense, but fevers also debilitate the body and are generally unpleasant. Therefore, for some infections, it would be highly beneficial to keep the temperature down. It is obviously more complex and with more exceptions than this. For Common Cold-type illnesses, the discomfort of a fever/weakness afterwards may outweigh a slightly longer recovery time, and it probably wouldn't be a bad idea to suppress it. Ask thy doctor. --.ιΙ Inhuman14 Ιι. 00:27, 25 January 2008 (UTC)

Does light move slowly at absolute zero?

Does light move slowly at absolute zero? ----Seans Potato Business 23:30, 23 January 2008 (UTC)

This question contains some false assumptions. First of all, temperature is only defined for systems in thermal equilibrium. An object at zero temperature emits no black-body radiation, so light cannot be in equilibrium with it. Light itself either has a non-zero temperature (if it has a black-body, or "thermal" spectrum) or an undefined temperature (for any other kind of spectrum, collectively called "non-thermal"). So, light "at absolute zero" doesn't exist at all.

Second of all, zero temperature doesn't simply mean everything moves as slowly as possible. It means everything is in its quantum ground state. But the ground state of the electromagnetic field is the one with no photons in it, again reinforcing my point that light doesn't exist at absolute zero. —Keenan Pepper 23:52, 23 January 2008 (UTC)

It may also be worth noting that the speed of light is really only of special interest in a vacuum (Cherenkov radiation is the easily-observed result of subatomic particles moving faster than the speed of light through a given medium), as that's where the speed is inviolate. Since temperature requires matter, a true vacuum can't be said to have a temperature at all. Whether the speed of light through other materials varies with temperature, I have no idea, though you're then back to the problems that Keenan Pepper addressed above. — Lomn 00:52, 24 January 2008 (UTC)

To get to the heart of what you're asking, your real question is "Does the speed of light vary with temperature?" The short answer is no, because usually when we say "speed of light" we mean "speed of light in a vacuum." In a true vacuum, as Lomn said, there is no matter, and thus temperature has no meaning (at least not the meaning we commonly ascribe to it). The longer answer includes the fact that light slows down in matter (see index of refraction). How much the light slows depends on the material and the wavelength of the light. Presumably the index of refraction (the measure of how much the light slows down) would also be dependent on the temperature of the material. The type of dependence would likely be different for different materials. -- 128.104.112.34 (talk) 17:20, 24 January 2008 (UTC)

You may take an interest on Bose-Einstein Condensates and their effects on the speed of light. --.ιΙ Inhuman14 Ιι. 00:28, 25 January 2008 (UTC)

"In 1999, Danish physicist Lene Vestergaard Hau led a team from Harvard University who succeeded in slowing a beam of light to about 17 metres per second and, in 2001, was able to momentarily stop a beam. She was able to achieve this by using a superfluid. Hau and her associates at Harvard University have since successfully transformed light into matter and back into light using Bose-Einstein condensates. Details of the experiment are discussed in an article in the journal Nature, 8 February 2007." Bose-Einstein condensates are formed at temps extremely close to zero, and have lots of wierd properties. --.ιΙ Inhuman14 Ιι. 00:52, 25 January 2008 (UTC)

Identification of this rock and minerals

Hi. I don't have a picture right now, and one wouldn't show much detail, but here goes. It is a black rock, hardness approximately 4 - 6 on the scale. I tried calculating its specific gravity once, I think I remember the mass as 21g, but I don't remember its volume. Let's see, it's approximately a severely rounded triangular pyramid, apporoximate dimentions: face 1, 3cm x 2cm x 2.5 cm; face 2, 3cm x 2cm x 2.5cm; face 3, 2cm x 2cm x 2.5 cm; face 4, 2.5cm x 2cm x 2cm. The point where faces 1, 2, and 4 join is slightly rounded but not flat, but if you consider it a face then it's 1cm x 1cm x 1.5cm. Approsimate location of origin: Manitoulin Island, Ontario (but I'm not sure). Originally I think it had a "volcanic" smell, or maybe that was the smell of sun-roasted rock. Its minerals are approximately 30 - 900 microns in diameter. It's very smooth, probably smoothened by water. So smooth, that if I rubbed its edge briskly on my hand, it won't scratch my hand (don't try this at home!). It appears dull, but if I rubbed a cloth over it repeatedly it will cause it to reflect a portion of the light, but not the image of the light source, and it will not hurt my eyes if I tried to reflect the image of the sun, but it's too dull and unflat to reflect the sun's image anyway. Finger grease will temporarily ruin its lustre and leave a faint removable imprint. It is completely opaque, although I've managed to view the crystals at the egde of the rock through a microscope via reflection, not transmition of light. The mineral crystals can be red, beige, grey, or reflective-transclucent. Permanent marker usually comes off with repeated washing. There are a few fractures, less than a millimetre wide and deep, although a few of them appear round and can thus be wider. The minerals are far to small to test or look for any cleavage/fracture. What is it? Basalt, maybe? What might some of its minerals be? Thanks. ~AH1^(TCU) 23:45, 23 January 2008 (UTC)

It could be basalt or teschenite. Graeme Bartlett (talk) 05:20, 24 January 2008 (UTC)