Wikipedia:Reference desk/Archives/Science/2011 August 7

= August 7 =

Reactive Oxygen Metabolites vs Reactive Oxygen Species
Is there a difference between 'Reactive Oxygen Metabolites' and 'Reactive Oxygen Species'?


 * The difference between the two is that Reactive Oxygen Metabolites refers specifically to the Reactive Oxygen Species produced as byproducts of metabolism. Reactive Oxygen Species on the other hand, refers to both metabolites and synthetic ROS. Hydrogen peroxide for example, is a ROS that is usually familiar to us in their synthetically (or otherwise naturally produced, but not by living processes) created form (i.e. not metabolites), but which are also produced naturally by organisms as [waste] products. Both can be called ROS, but only the latter is ROM.--  Obsidi ♠ n   Soul   15:46, 8 August 2011 (UTC)

Do people actually sleeps like this?
See image on this link. 

Is this real or is it a joke? Ohanian (talk) 10:26, 7 August 2011 (UTC)


 * It might well be a joke (tempting to wake her up...) but it could be real. After all, fairly often I use a position with one foot up in the air balanced against a knee in a tetrahedron.  As anyone who's had a stiff neck should know, sleep paralysis seems to involve actively maintaining muscular tension, not just flopping lifelessly. Wnt (talk) 11:37, 7 August 2011 (UTC)

I can state with absolute factual knowledge.. It's not a joke. When I was a child I quite often slept in exactly that position. I can't say why, my body just automatically sought that position for comfort.190.56.115.12 (talk) 14:32, 7 August 2011 (UTC)


 * I can also confirm it's not a joke. My daughter often sleeps in this position, and so did her grandmother as a child. But the habit appears to have jumped a generation. Hans Adler 15:10, 7 August 2011 (UTC)


 * I've seen infants sleeping in that position, but not adults. But anything's possible. ←Baseball Bugs What's up, Doc? carrots→ 18:42, 7 August 2011 (UTC)


 * Is there a name for that sleeping position? Bus stop (talk) 18:47, 7 August 2011 (UTC)


 * My 2.5-year old son sleeps exactly like that. My wife and I often comment on how uncomfortable it looks, but this is one of those personal preference/subjective things.  If it works, who are we to care... -- Jayron  32  18:58, 7 August 2011 (UTC)


 * I was thinking the most obvious name for it would be the "bottoms up" position. Googling [sleeping positions], the general stomach-down position seems to be called "freefall". I don't know if that term would apply to this particular face-down position. ←Baseball Bugs What's up, Doc? carrots→ 19:00, 7 August 2011 (UTC)


 * Of course, wikipedia has articles on everything. I can't yet find a name for this position, but I did find Human positions and a spinoff article titled Sleeping positions and the category Category:Human body positions.  -- Jayron  32  19:03, 7 August 2011 (UTC)
 * It's a completely different context, but I did fine the article Kowtow which is almost the exact same body position. -- Jayron  32  19:05, 7 August 2011 (UTC)


 * Photographs of sleeping babies. Bus stop (talk) 19:07, 7 August 2011 (UTC)
 * Cute, but every one of those pictures looks "posed" by someone other than the sleeper. I'm not sure any of them represents a natural "sleeping" position the child would have assumed if left to its own devices.  -- Jayron  32  19:12, 7 August 2011 (UTC)
 * They do at that, but I have seen infants sleeping in that "bottoms up" position. One thing to keep in mind is that their legs are very short compared with adults, which is why I find it hard to believe that would be a comfortable position for an adult. But it takes all kinds. ←Baseball Bugs What's up, Doc? carrots→ 22:53, 7 August 2011 (UTC)
 * The Muslim prayer position is also similar to this. ~ AH1 (discuss!) 23:40, 7 August 2011 (UTC)
 * Lordosis behavior. Cuddlyable3 (talk) 07:20, 8 August 2011 (UTC)
 * I'm just speculating, but that looks like a very safe position to sleep in. Your most delicate areas (face, abdomen, groin) are all protected. It's not dissimilar to the foetal position, but it is probably easier to sleep like that than in the foetal position (I find I need to hold my knees in place with my arms if I'm going to stay in the foetal position). --Tango (talk) 14:34, 8 August 2011 (UTC)

Oh, my! μηδείς (talk) 01:10, 9 August 2011 (UTC)

CHOCK
What is the back emf produced across the electrical ballast at the time when the supply to the tube light is OFF.vsnkumar (talk) 11:02, 7 August 2011 (UTC)
 * Welcome to . Your question appears to be a homework question. I apologize if this is a misinterpretation, but it is our policy here not to 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 nearly as much as doing it yourself. Please attempt to solve the problem or answer the question 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.
 * To calculate the back-emf in an inductor, you need to to know the voltage across the inductor, its inductance, and the resistance of any discharge path. CS Miller (talk) 12:00, 7 August 2011 (UTC)
 * To calculate the back-emf in an inductor, you need to to know the voltage across the inductor, its inductance, and the resistance of any discharge path. CS Miller (talk) 12:00, 7 August 2011 (UTC)

Chicken lays eggs with double yolks
I have 6 chickens and one of the chickens lays a large egg which has two yolks each time she lays. My question is: If I were to have a rooster around and her eggs were fertile, would there be any possibility that two chicks would come from her egg(twins)? I'm new at raising chickens. — Preceding unsigned comment added by User:TerrDA (talk • contribs)
 * Theoretically yes. But I have asked around and it seems twin chicks from one egg is not recorded, probably because there is not room in the egg for two embryos to mature. Cuddlyable3 (talk) 18:20, 7 August 2011 (UTC)
 * Take a look here. Twin chicks from a single egg has happened, but only with human intervention. When I saw double yolked eggs as a kid, I always assumed that they'd come out as Siamese twins if they were allowed to hatch. --Kurt Shaped Box (talk) 18:33, 7 August 2011 (UTC)

One major problem with the double-yolked egg is the decreased surface area available for the chicks to perform gas exchange. Surface-area-to-volume ratio. The surface between them becomes a dead space. Doble yolked eggs would produce fraternal twins. Conjoined twins are possible from a single yolk. μηδείς (talk) 01:18, 9 August 2011 (UTC)

Speed of light
why cant we travel faster than the speed of light?why does laws of physics prevent us? — Preceding unsigned comment added by 175.110.242.217 (talk • contribs)
 * Have you read the Speed of light article's section about upper limit on speeds? -- JSBillings  18:11, 7 August 2011 (UTC)


 * (ec):Wikipedia has an article about the Speed of light but you may like to read this article first. Cuddlyable3 (talk) 18:12, 7 August 2011 (UTC)


 * See also superluminal communication. ~ AH1 (discuss!) 23:33, 7 August 2011 (UTC)

Here are the fastest speeds by a man compared to the speed of light c Cuddlyable3 (talk) 07:39, 8 August 2011 (UTC)
 * Sprinter 10.35 m/s = c / 107
 * Plane SR-71 "Blackbird" 600 m/s = 2c / 106
 * You and me on Earth going around the Sun 30 000 m/s = c / 104
 * You and me and the local group of galaxies going towards the constellation Hydra 600 000 m/s = 2c / 103
 * Speed of light 299 792 458 m/s = c

Tea "espresso"
Lately I prefer tea to coffee, but traditionally I drank espresso, and when drinking tea I like it to be very strong, bitter, and highly caffeinated. I use several teaspoons (or sachets) of black tea per cup of water, and let it steep for ages. Still I would prefer something more concentrated. Is there a way to brew tea that will yield a beverage comparable to espresso? I don't hope to replicate the texture, because tea is much less oily than coffee, but I would at least like to have something equally caffeinated, and which can be drunk in a very small quantity. L ANTZY T ALK 18:01, 7 August 2011 (UTC)
 * Iranian Persian style tea is so strong that they consume it while holding a sugar cube in the mouth to sweeten it. I believe they usually brew with a samovar but I'm not sure what the exact process is. Beeblebrox (talk) 18:39, 7 August 2011 (UTC)
 * If you want stronger tea (this is actually true for coffee as well, since they both are produced from steeping), you'll just want to use more tea when you steep. There is somewhat of a misconception that steeping longer will make it stronger; however longer steeping times tends to extract a higher percentage of undesirable flavor compounds, which can actually make the tea less "tea like".  Of course, tastes vary, but if you want a stronger "tea" flavor, you'll want to use more tea when you steep it; don't alter the standard steeping time, just use more.  -- Jayron  32  18:46, 7 August 2011 (UTC)
 * You probably know this already, but the variety of tea makes a big difference - Assam typically gives a much darker and stronger brew than Darjeeling for example, though both are black teas. AndrewWTaylor (talk) 20:44, 7 August 2011 (UTC)

If you want maximal concentration, boil it down. That's what the Tibetans do to make their famous (or infamous) butter tea: they dump a mass of tea leaves into boiling water and boil it for half a day. Looie496 (talk) 23:39, 7 August 2011 (UTC)
 * Good point. I considered this, but it turned out not to be necessary. My experiment: I steeped 200 grams of Assam tea ("Irish breakfast") in c. 800 ml of water (in a French press), and ended up with about 500 ml of opaque red-brown liquid. Texturally it resembles espresso, even having a pale creamy foam on top, and like espresso it leaves a distinct residue behind in the cup. The taste is astringent, herbal, and cleaner than espresso, leaving less of an aftertaste. If you drink espresso for the caffeine, this will do the trick just as well. I'm still curious as to whether I could produce the same thing more efficiently in an espresso maker. Actually, I'm surprised it hasn't been attempted before. People like espresso, people like tea... so why not tea-spresso? L ANTZY T ALK 02:55, 8 August 2011 (UTC)


 * I think you are only drinking it for the caffeine, since "stewing" it as we call it over here makes it taste very bitter due to the tannins etc leaching out of the tea leraves. Personally I prefer tea that was been in contact with tea leaves for just a few seconds, as that gives the best flavour as the tannins do not have time to leave. Green tea is said to have more caffeine than black tea. Perhaps you could try drinking it Japanese style. 92.28.240.88 (talk) 10:25, 8 August 2011 (UTC)


 * Stewed tea certainly gives you a buzz (by the way, if you're drinking it for caffeine, quantity often helps: at uni I went through a phase of using a ginormous pint-and-a-bit mug) and the taste isn't actually too unpleasant. Best stop shy of chifir though. Brammers (talk/c) 15:13, 8 August 2011 (UTC)


 * Oh, my, so that's the stuff the Russians in the lab made... I only remembered them calling it "chai". They were very finicky about getting just the right kind of black Indian tea for it.  I think definitely if the DEA had been around to taste that stuff in the Middle Ages, tea would be selling for $300 an ounce today and every other person in America would be drinking it. Wnt (talk) 18:32, 8 August 2011 (UTC)

Coca tea is also quite strong. Count Iblis (talk) 20:21, 8 August 2011 (UTC)


 * I think so much caffeine is unhealthy and bad for you. Does the OP have trouble sleeping? If you insist, despite the bad health effects, on consuming high quantities of caffeine, then why not just take caffeine tablets? Then you could drink normal tea and enjoy its taste. 92.24.191.250 (talk) 20:57, 8 August 2011 (UTC)

Mitochondrial Inheritance
Hello. If sperm mitochondria degrade in the egg cytoplasm after fertilization, why can the egg mitochondria survive? Thanks in advance. --Mayfare (talk) 19:00, 7 August 2011 (UTC)
 * Our article on Mitochondrial DNA actually addresses this very question, specifically the section on Female inheritance. Vespine (talk) 02:30, 8 August 2011 (UTC)

I meant to ask: how does the egg tell apart paternal mitochondria from maternal mitochondria so that it degrades paternal mitochondria? --Mayfare (talk) 19:38, 9 August 2011 (UTC)
 * And I meant that the answer to that question is in our article on Mitochondrial DNA, specifically the section on Female inheritance. Vespine (talk) 22:23, 9 August 2011 (UTC)

Language++
In a recent discussion about the "invention" of language (presumably THE milestone of human cerebral(?) / social / cultural development) we - a group of midly intoxicated rambling geezers of nascent senility - wondered idly:

Have scientists (from biologists to futurologists to SF writers) speculated on theoretical evolutionary / cognitive "quantum leaps" which may be as revolutionary as the development of oral and written language?

I am aware that some scientists expect genetic enhancement / nanotechnology / cerebral to digital interfaces and even consider the possibility of a "fully digitalised" non-corporeal HS as a possible future. I am, however, not so much interested in "engineered" evolution and apologize for a border-line crystal gazing question. Thank you for any ideas! --Cookatoo.ergo.ZooM (talk) 21:11, 7 August 2011 (UTC)
 * R. Daneel Olivaw (especially his later appearences in fiction) may provide some interesting ideas for you. -- Jayron  32  23:37, 7 August 2011 (UTC)
 * Wikipedia also has the article Infomorph (a term I had never heard before) which I tripped over while remembering the character "The Dixie Flatline" from Neuromancer, which also has some advanced ideas about consciousness. Also, John Scalzi's "Old Man's War" series has some interesting stuff on transferance of consciousness and soul from one body to another.  -- Jayron  32  01:22, 8 August 2011 (UTC)
 * The article Origin of language speculates on the onset in prehistory of human spoken language but the pivotal development was written language. This enabled dissemination of information and its flow from each generation to the next, and the consolidation and identification of competing societies by their diverse textual languages. Cuddlyable3 (talk) 07:53, 8 August 2011 (UTC)
 * There is some debate, however, among scholars as to the importance of oral tradition in terms of preservation of knowledge. Pre-literate societies still managed to do some pretty amazing stuff, technologically speaking, without formal written language.  The Incas, for example, had no written representation of their spoken language (the closest they had was a knotted string which they used as a form of accounting), and yet were able to build a highly developed civilization with some pretty advanced engineering.  Certainly, written language is very important, but there are some counterexamples where some rather advanced civilizations got along without it.  -- Jayron  32  13:28, 8 August 2011 (UTC)
 * See Hippocampal prosthesis. Provided sufficient bandwidth of communication, this is what you're looking for.  For further details see Mark of the Beast and Revelation of John. Wnt (talk) 13:58, 8 August 2011 (UTC)
 * Urk. The "hippocampal prosthesis" is pseudoscience, in my opinion. Looie496 (talk) 21:49, 8 August 2011 (UTC)
 * DoubleplusUrk. The Bible is not a reliable source of details for brain surgery. Cuddlyable3 (talk) 00:24, 10 August 2011 (UTC)


 * Written language was a lot harder from an evolutionary perspective than spoken language. It's important to see them as quite different things. The idea of written language has only been independently invented a few times in human history, as far as we can tell, whereas oral traditions seem to spring up spontaneously. --Mr.98 (talk) 15:22, 8 August 2011 (UTC)

For the necessary developmental stages in the evolution of language and the modern mind from ape to external storage read the works of Merlin Donald. I became aware of him by reading Oliver Sacks and I cannot recommend his two books strongly enough. μηδείς (talk) 01:28, 9 August 2011 (UTC)

nucleon model
When you feed all of the known and speculated parameters of a nucleon into a supercomputer what sort of model does the supercomputer predict? --DeeperQA (talk) 23:36, 7 August 2011 (UTC)
 * What do you mean "feed" and "supercomputer". I am thoroughly confused about what you are asking.  The computer doesn't predict anything.  It predicts what humans tell it that it will.  If you want to know what we currently know about nucleons, read the article nucleon.  -- Jayron  32  23:39, 7 August 2011 (UTC)
 * It is the same sort of process used to model or predict future weather albeit for only a short distance in time. We feed the computer data from weather patterns gathered over long periods of time and ask it to find parameters. Then we feed the parameters back into the computer and see what model the computer comes up with similar to performing Fourier analysis on music to derive the coefficients of each harmonic which we can feed back as is or alter the value of each harmonic independently to see what sort of music we might get back. In the case of the nucleon we are asking the computer to find the model that fits all of the parameters best. --DeeperQA (talk) 00:03, 8 August 2011 (UTC)
 * Yes, but the difference is, we don't know (without the computer models) what the weather is going to be like next week. We do, however, know what the nucleon is going to look like next week.  Now, pretty much all of what we know about the nucleon is based on data from complex computer models, so if your question is "what do existing computer models tell us that nucleons behave like" then the answer is "see nucleon".  If the question is "how do computers help us probe the behavior of nucleons" then you'll want to research more into the fields of Computational chemistry and Computational physics.  -- Jayron  32  00:14, 8 August 2011 (UTC)
 * No, my question is strictly one relating to geometry. --DeeperQA (talk) 00:27, 8 August 2011 (UTC)
 * In that case, we know next to nothing about the internal geometry of nucleons.  The best work in this area is in the field of Lattice QCD, so you may want to look there for your research.  -- Jayron  32  00:29, 8 August 2011 (UTC)
 * Taking a step back: Computers do not magically give you a model. In addition to the data, you also have to feed it with a model (in the form of a computer program), based on a physical theory and some assumptions regarding geometry etc. The model may contain free parameters (e.g. coupling constants), in which case you can use the computer to determine the parameter values (in the context of that model) which give the best fit to the data. Alternatively, if you know the values of the parameters, then you can fix them and predict a future state of the system that you are trying to describe. --Wrongfilter (talk) 10:53, 8 August 2011 (UTC)
 * As I indicated that is true for harmonic coefficients which are known and for neural networks which have weights that are known. But harmonic analysis has the ability to find harmonic coefficients while neural networks have the ability to find weights while in training mode that can be used as a model on which to explore possibilities not found in the training data. --DeeperQA (talk) 15:04, 8 August 2011 (UTC)

shortest inverval of time
What is the shortest interval of time in which the Large Hadron Collider (LHC) can detect a product of the collision of two protons? --DeeperQA (talk) 23:55, 7 August 2011 (UTC)


 * The products of the reaction fly away from the collision and are detected centimeters to meters away after picoseconds to nanoseconds have passed. The equipment typically can resolve an event with roughly nanosecond timing.  Is that what you wanted to know?  Dragons flight (talk) 06:55, 8 August 2011 (UTC)
 * Are you saying that the product paths (line of dots) have dots that are spaced at intervals of one nanosecond? If so then yeas. --DeeperQA (talk) 13:47, 8 August 2011 (UTC)
 * If so then what are that chances of capturing a par tile that last for less than a nanosecond? --DeeperQA (talk) 15:40, 8 August 2011 (UTC)
 * Manual study off line of the products of a collision will take much longer. Cuddlyable3 (talk) 08:42, 8 August 2011 (UTC)