Wikipedia:Reference desk/Archives/Science/2010 March 7
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March 7
editSaturn and Jupiter
editIf the mass of Jupiter and Saturn were combined would there be enough mass, density and gravity to result in fusion? 71.100.11.118 (talk) 01:41, 7 March 2010 (UTC)
- No. See Brown dwarf - the theoretical minimum size of a star in which fusion occurs is about 75 times the mass of Jupiter, and the smallest known star is AB Doradus C with a mass 93 times that of Jupiter. Saturn's mass is only about 0.3 times that of Jupiter, so adding them together wouldn't make a significant difference. Tevildo (talk) 01:56, 7 March 2010 (UTC)
- At 75 times the mass of Jupiter, fusion occurs. At more than 13 times the mass of Jupiter, a star becomes a brown dwarf and produces heat and light by the star shrinking under its own weight. --The High Fin Sperm Whale 03:03, 7 March 2010 (UTC)
- According to our article, "brown dwarfs heavier than 13 MJ do fuse deuterium and those above ~65 MJ also fuse lithium." Both isotopes/elements however would be present in far smaller proportions than the hydrogen that begins to be fused from 75 MJ upwards, so what fusion does occur is thought to be unable to prevent the brown dwarf from cooling quite quickly (by stellar standards) below fusion-sustaining temperatures. 87.81.230.195 (talk) 06:21, 7 March 2010 (UTC)
- At 75 times the mass of Jupiter, fusion occurs. At more than 13 times the mass of Jupiter, a star becomes a brown dwarf and produces heat and light by the star shrinking under its own weight. --The High Fin Sperm Whale 03:03, 7 March 2010 (UTC)
is Jupiter made of the right stuff to be a star, if it were bigger? If so, then is the only difference between a planet like Jupiter and a Sun that the former is too widdle to fuse? Instead of planets then why don't we call them little not-stars? 82.113.121.94 (talk) 11:49, 7 March 2010 (UTC)
- You find the reason why we call them planets in the lead and the first section of the article Planet. DVdm (talk) 11:56, 7 March 2010 (UTC)
classifying reaction?
editWhat kind of chemical reaction is Cu+2H2SO4-->CuSO4+2H2+SO2
thanks in advance...
174.112.38.185 (talk) 02:46, 7 March 2010 (UTC)
- see Redox, hydrogen production, solution, corrosion, pollution. Graeme Bartlett (talk) 04:08, 7 March 2010 (UTC)
- I would be surprised if this reaction could really happen. 93.132.150.52 (talk) 09:30, 7 March 2010 (UTC)
- The caption of one of the images on the Copper(II) sulfate page says it can be made by electrolysis. It wouldn't surprise me as it seems, at a glance, to be strongly entropically favourable, with a solid metal and six aqueous ions forming two aqueous ions and three equivalents of gas, which would then bubble off, slamming the equilibrium in favour of the products. Brammers (talk) 10:12, 7 March 2010 (UTC)
- The reaction is a magical way to hide 2 atoms of oxygen. Cuddlyable3 (talk) 17:40, 7 March 2010 (UTC)
- The caption of one of the images on the Copper(II) sulfate page says it can be made by electrolysis. It wouldn't surprise me as it seems, at a glance, to be strongly entropically favourable, with a solid metal and six aqueous ions forming two aqueous ions and three equivalents of gas, which would then bubble off, slamming the equilibrium in favour of the products. Brammers (talk) 10:12, 7 March 2010 (UTC)
- This sort of thing can actually happen when you heat copper in sulfuric acid, you may not get hydrogen produced however, getting water produced at the end instead. Same thing happens with mercury (don't try this at home). Graeme Bartlett (talk) 22:12, 7 March 2010 (UTC)
- Is SO4 a molecule that could exist? If the last molecule were SO4 rather than SO2, then Cuddlyable3's objection would be satisfied. Otherwise if O2 were evolved it could balance. (I know something of electricity, less of chemistry).(Gee, I have some sulfuric acid and copper in the basement. Should I try the experiment? Naah!).Edison (talk) 23:33, 7 March 2010 (UTC)
- It called a reaction that don't work :-). Copper is the "wrong" side of hydrogen in the electrochemical series. Most metals will react to give off hydrogen, copper is the odd one out. Copper only dissolves with an oxidant - nitric acid will do nicely. Ronhjones (Talk) 23:47, 7 March 2010 (UTC)
- Pure sulfuric acid though can oxidise copper, I checked it out in an Inorganic Chemistry text book, in the sulfur dioxide section, it is one way to make SO2. Graeme Bartlett (talk) 00:33, 8 March 2010 (UTC)
star birth, life,and death equation and graph
editis there an equation and graph that shows each of the basic conditions, i.e., gravity, diameter, volume density rate of fusion of a star over time for each sequence (big bang to cloud of hydrogen through the collapse of an iron core to the formation of a neutron star and eventually a black hole and beyond) over time? 71.100.11.118 (talk) 04:29, 7 March 2010 (UTC)
- How about, instead, thinking about saying "Not that I know of", which would be more accurate; and then realizing that it's better to not post than just to post either "no" or "not that I know of"? Comet Tuttle (talk) 07:30, 7 March 2010 (UTC)
- How about keeping your sanctimonious pedantry to yourself? (Oh, I forgot -- there's no WP:KYSPTY rule, so you're perfectly legit.) 63.17.52.111 (talk) 11:02, 7 March 2010 (UTC)
- Do you really advocate the unreferenced answer "no" for a reasonable refdesk question? That doesn't improve the refdesk at all. We are a reference desk, and we're supposed to supply references, not lazy rejections. Comet Tuttle (talk) 15:56, 7 March 2010 (UTC)
- I said no because that's the correct answer. Many equations and graphs and charts and diagrams are needed to show all of that, it can't possibly all be put into one. And how exactly am I going to find a source proving that something doesn't exist ? That's just silly. If you think I'm wrong, let's see some sources supporting your position. StuRat (talk) 16:01, 7 March 2010 (UTC)
- I'm not asserting that you're wrong; I'm asserting that an unreferenced "No" is an unacceptable answer on the refdesk. If you had typed the above paragraph as your original answer, I would not have complained at all. Comet Tuttle (talk) 16:55, 7 March 2010 (UTC)
- It's still an unreferenced "No". Are you saying that it's now acceptable because I explained why the answer is no, or because I explained that it's impossible to provide a source for something which doesn't exist ? StuRat (talk) 20:36, 7 March 2010 (UTC)
- Absolutely that would be a better answer. "No - because you can't fit all that stuff on one sheet of paper" would have been a useful answer. Particularly if you could explain why not. Just "No" is a very low-information-content response. So yes - your first answer was awful - with the clarification, it's borderline useful. The best answer would have been "No, you can't fit all of that on one sheet of paper - but here, here, here and here are the separate graphs and charts that will give you the information you need." As you will note below, the answer "Have you read out Stellar evolution article?" was judged by the OP to be useful. SteveBaker (talk) 23:02, 7 March 2010 (UTC)
- They said it contained some useful info, but that it didn't answer the Q. The answer to the Q was "No". We can explain why that's the answer, but I doubt if you will find any links that say why you can't fit all that info on one page, which is what was actually asked. StuRat (talk) 00:08, 8 March 2010 (UTC)
- I agree that making such a chart would be very difficult - but if you just say "No" then that might have been because the chart simply doesn't exist because nobody could be bothered to make one - or it might be because the information isn't available - or it might be because the sheet of paper would have to be too big - or (the truth) it might be because the resulting chart would be an unreadable mess. But the reason that there isn't such a chart is really very important. The purpose here is to help our questioner - not just to provide a literal boolean answer to the question. Your "No" response was true but 100% useless since one's first feeling on reading that is "How the hell could this guy possibly know that such a chart doesn't exists? He hasn't read every astronomy book in the world!" - so you aren't conveying the information needed for the answer to be remotely believable. Sure you can't find a reference for that - but there were ways you could have said something like: "There are X kinds of star and Y different parameters to be graphed for each star type so there would be X x Y lines on that graph and it would need Y columns of numbers on the vertical axis and you'd need to draw all of those curves with X x Y colors or line styles." Assuming that X and Y are reasonably large numbers - it would be clear why such a diagram would either be impossible, or really cluttered or actually unreadable. SteveBaker (talk) 04:55, 8 March 2010 (UTC)
- While I agree that going beyond simply answering the question (as I did) to explain in depth how that answer was derived might be helpful, I don't agree that I should either do that or not answer. There's no requirement that each individual response be comprehensive. Thus, one person can answer and another can elaborate. I've often done the elaboration part myself. StuRat (talk) 10:26, 8 March 2010 (UTC)
- How about for each sequence, including non-wiki articles? 71.100.11.118 (talk) 05:15, 7 March 2010 (UTC)
- Have you read our Stellar evolution article? Comet Tuttle (talk) 07:30, 7 March 2010 (UTC)
- Thanks for the ref. That article has some good stuff in it. What I had in mind though was a chart where core gravity, diameter, volume, density, rate of fusion, etc. (all of the basic measurements were plotted over life cycle and the equations that correlate rate of fusion with star diameter, etc. 71.100.11.118 (talk) 12:21, 7 March 2010 (UTC)
Life expectancy
editIn an interview I was watching, a man claimed that in the cave man era, if infant mortality were ignored, the average life expectancy of people would be roughly 70 years. I'm a little skeptical, is there any evidence that this is true? —Preceding unsigned comment added by 173.179.59.66 (talk) 09:19, 7 March 2010 (UTC)
- The move away from nomadic hunter gather to neolithic settlements appears to have drastically increased the disease burden; which got worse as villages became towns and towns grew into cites. Things did not improve until the introduction of modern sewerage systems. There is little hard physical evidence to support the idea that palaeolithic people had longer life spans but there are good augments to suggest this: Grandmothering, menopause, and the evolution of human life histories--Aspro (talk) 11:10, 7 March 2010 (UTC)
- The fact that human females are able to live for so long after they are no longer able to bear children suggests that there is evolutionary benefit to living beyond ~40 years that is nothing to do with reproductive ability. People who outlived their reproductive usefulness would consume food and other resources that the rest of the tribe needed - and that would impose evolutionary pressure for people to die at an age just beyond that at which their children became mature. People with the "die at 40" gene would have more successful children - and that gene would outperform the "die at 80" gene that would result in twice as much food consumption by a group of humans that would limit the number of surviving children into future generations.
- But if that were true - then we wouldn't live much longer than 40 years...and we obviously do. Most other animals die of old age not long after they cease to be fertile. No amount of good health care, nutrition, comfortable living, etc will allow a dog to live more than about 15 years - or a mouse beyond about 3 years. But both are fertile until almost the end. So for humans to be so different, there must have been other benefits of long life (eg the ability to bear knowledge across multiple generations - or that 40 years of experience make for a better hunter than 20 years - so that the older people could produce more benefit than they 'cost').
- We haven't really had time to evolve that long-life ability recently - so it was probably around in palaeolithic times - which probably means that at least some people lived to these kinds of ages. What's tough is to know the average age back then. Did just 1% live to 70 or did most people who survived childhood live that long? SteveBaker (talk) 22:52, 7 March 2010 (UTC)
- The long childhood of humans meant that parents need to stay around for a much longer time after their last kid is born, if they expected it to survive. StuRat (talk) 01:47, 8 March 2010 (UTC)
- Fascinating stuff, thanks for the detailed answer. By the way, is there any particular reason why diseases were more prevalent in sedentary societies? And how then were agriculture-based societies able to out-develop their nomadic counterparts? —Preceding unsigned comment added by 173.179.59.66 (talk) 01:12, 8 March 2010 (UTC)
- Sedentary societies usually involve higher population densities and close contact with animals. Both of those factors contribute to increased disease. Agriculture allows people to produce more food than hunting and gathering (in some environments, anyway), which allows some people not to work on getting food. That frees them up for developing other crafts and for politics (which allows better coordination of large groups). --Tango (talk) 01:37, 8 March 2010 (UTC)
- Unless such a statement came from a respected member of a culture that ostracizes community members who make controversial statements of fact without evidence (i.e., a scientist), I would be deeply skeptical of such an appeal to nature. --Sean 19:34, 9 March 2010 (UTC)
Temperature of outer space
editIf space is a vacuum, how can it be a temperature be associated with it? 173.179.59.66 (talk) 09:22, 7 March 2010 (UTC)
There is not usually a temperature associated with the vacuum of space. If someone does refer to the temperature of space, they usually mean the temperature of the cosmic background radiation or of the very low-density interplanetary medium or interstellar medium.83.134.173.114 (talk) 10:20, 7 March 2010 (UTC)
- So the vacuum of space is temperatureless? —Preceding unsigned comment added by ApplePie456 (talk • contribs) 11:39, 7 March 2010 (UTC)
- No, vacuum can still have radiation which wiil have a temperature. That would be the cosmic background radiation mentioned above.Dauto (talk) 14:14, 7 March 2010 (UTC)
- The vacuum of space apparently does not hve a "temperature" other than the extremely low temperature of the cosmic background radiation referred to above. But an object in space will have a temperature, as would be measured by a thermometer in it or on its surface. A spacecraft in orbit will get very hot on the side facing the sun, depending on its absorption of the solar radiation, which amounts to something over 1 kilowatt per square meter. A white spacecraft would absorb less energy than a black one. See Albedo. The same is true for an object on the surface of the Moon where the sun is shining. Conversely, a spacecraft (or the side of a spececraft) which is in the dark will radiate off heat and can get extremely cold. NASA astronauts referred to the rotation of a spacecraft to even out the temperature "barbecue mode." Coolant can be circulated through tubes to even out the temperature. In the ill fated Apollo 13 moon mission, the spacecraft had to power down and it got very cold inside while they were travelling back to Earth after passing around the Moon. If the outside of the craft had been painted to absorb more solar energy, it would have been warmer. Edison (talk) 14:21, 7 March 2010 (UTC)
- The key thing to remember about our definition of temperature is that it requires matter (unless you're talking about the background radiation mentioned above). You can only refer to conventional temperature when there is matter to study the kinetic energy of, so any floating material in the 'vacuum' of space (I use the term lightly, as there's actually quite a bit of matter floating around) will have a temperature, but the empty parts won't (except for the cosmic background radiation, see above). Regards, --—Cyclonenim | Chat 15:00, 7 March 2010 (UTC)
- You say you use the term vacuum "lightly" to refer to outer space. I have read that space has a hard vacuum, equal to or better than any that can be achieved with the best technology on Earth. Maybe our vacuum pump technology has improved since I was last concerned with the quality of obtainable vacuum. Any vacuum tube would supposedly work fine there. Do you have a reference that supports your contempt for the quality of the vacuum seen in space, compared to what a vacuum pump can achieve on Earth? Edison (talk) 22:58, 7 March 2010 (UTC)
- There is no reason to see the radiation temperature as any different from the temperature of matter and since radiation permeates space it is always possible to define the temperature of vacuum and by the third law of thermodynamics it is always different from zero. Dauto (talk) 20:29, 7 March 2010 (UTC)
- Right. Cycloneim, this is important: Temperature per se has nothing whatsoever to do with kinetic energy per se. Temperature is defined by the relationship between entropy and internal energy. The only time you can use kinetic energy as an accurate proxy for temperature is when you're dealing with a monatomic medium, so that none of the energy goes into vibrational modes. --Trovatore (talk) 20:34, 7 March 2010 (UTC)
- Actually I take back the "nothing whatsoever" — that was too strong. Certainly kinetic energy will increase when temperature does, and that in itself is some relationship.
- The point I wanted to make is that many people seem to think that temperature is conceptually a matter of kinetic energy. And that's completely wrong. --Trovatore (talk) 20:46, 7 March 2010 (UTC)
- Then I apologise, I'm no physicist but closer to a biologist so I suppose my definitions are very limited to molecular structures. Temperature is indeed a measure of kinetic energy in particles though, isn't it? If not, someone needs to go fix the article temperature if that's not it's primary definition, because that's the very first sentence in the lead. Regards, --—Cyclonenim | Chat 22:10, 7 March 2010 (UTC)
- To the extent that the particles are like billiard balls, whose internal structure can be ignored, and which don't interact except via elastic collision, you can treat it that way. But molecules you specifically can't. Molecules have vibrational and rotational modes. The temperature gives you a unit of energy that is distributed equally among the modes, not equally among the particles. --Trovatore (talk) 00:26, 8 March 2010 (UTC)
- Then I apologise, I'm no physicist but closer to a biologist so I suppose my definitions are very limited to molecular structures. Temperature is indeed a measure of kinetic energy in particles though, isn't it? If not, someone needs to go fix the article temperature if that's not it's primary definition, because that's the very first sentence in the lead. Regards, --—Cyclonenim | Chat 22:10, 7 March 2010 (UTC)
- Right. Cycloneim, this is important: Temperature per se has nothing whatsoever to do with kinetic energy per se. Temperature is defined by the relationship between entropy and internal energy. The only time you can use kinetic energy as an accurate proxy for temperature is when you're dealing with a monatomic medium, so that none of the energy goes into vibrational modes. --Trovatore (talk) 20:34, 7 March 2010 (UTC)
- Another way to see that the energy formulation (even when modes are considered) is inadequate is to note that some systems have negative temperature. (You can't have a whole object at negative temperature, but you can have, say, its system of magnetic spins at negative temperature.) But this certainly doesn't mean negative energy! Actually, it's higher energy than a
positive-energypositive-temperature state of the same system. --Trovatore (talk) 00:38, 8 March 2010 (UTC)
- Another way to see that the energy formulation (even when modes are considered) is inadequate is to note that some systems have negative temperature. (You can't have a whole object at negative temperature, but you can have, say, its system of magnetic spins at negative temperature.) But this certainly doesn't mean negative energy! Actually, it's higher energy than a
- The problem here is that there are at least two subtly different meanings for this word "temperature". Classically, it's a measurement of the speed that molecules are jiggling around in a liquid, solid or gas - and in that sense, a vacuum really doesn't have a temperature. However, you can talk about the kinetic energy of those molecules as "heat energy" which can be related to a temperature - and when you do that, you can speak meaningfully of "temperature" as a more general measure of the energy present. In that interpretation, the photons and other radiation within the vacuum "counts" in that energy measurement - so now you can talk about the temperature of a vacuum. The distinction is another one of these "what does this word mean" problems rather than some physical thing. SteveBaker (talk) 22:30, 7 March 2010 (UTC)
- No, the "speed" version is really just wrong. See above. --Trovatore (talk) 00:40, 8 March 2010 (UTC)
OP here. So to make sure I understood, the temperature of outerspace near the earth would be quite high, because of the contribution of the sun's radiation, and this would be true regardless of whether there's actually any matter present. Meanwhile, far from the solar system (or any star for that matter), space is very cold, with a temperature associated with the cosmic microwave radiation. Is this correct? —Preceding unsigned comment added by 173.179.59.66 (talk) 01:30, 8 March 2010 (UTC)
- Well, no, it's not that simple. "Outerspace near the Earth" is not in thermal equilibrium, so it doesn't have a single well-defined temperature. What it has, you might say, is multiple temperatures, for different subsystems that are in some sort of equilibrium. For example, the solar wind is very hot indeed (much hotter than the radiation temperature of the Sun) -- millions of degrees if I recall correctly, which I may not. The reason you don't get fried by it instantly is that it has very low heat capacity and thermal conductivity, so the interplanetary medium right next to your spacecraft quickly delivers its negligible heat and cools off, whereas the stuff just a little farther away can't get its heat to you efficiently at all, so it doesn't bother you.
- On the other hand the cosmic microwave background is also there, and it's at 2.7 K (if I remember the number right), as always. --Trovatore (talk) 08:24, 8 March 2010 (UTC)
- And there is also the radiation coming from earth at roughly 300K and the cosmic neutrino background at 1.8K, etc... 174.58.105.234 (talk) 21:12, 8 March 2010 (UTC)
most of these are just hypotheses...space research is still in its infancy and scientists are using various experimental results to genaralise and postulate their hypothesis again and again. one fine day they would stumble upon something which would diametrically alter what is now perceived to be correct.
mind waves
editis there any thing like mind waves? can a person just receive those mind waves? what type of energy are they really sound waves? —Preceding unsigned comment added by Myownid420 (talk • contribs) 09:50, 7 March 2010 (UTC)
- You might want to read Electroencephalography. 93.132.150.52 (talk) 11:56, 7 March 2010 (UTC)
- By recording cortical evoked potentials, it has been possible to read the mind to a limited extent. The Pentagon theough DARPA funded such experiments in the 1970's. See [1]. The thing being collected is very weak electrical potentials on the scalp which result from electrochemical activity in various brain regions and neural pathways. It is a very indirect measure, like determining when there are breaks in a televised sports program by noting the variations in water pressure due to toilet flushing. Edison (talk) 14:29, 7 March 2010 (UTC)
- You might want to read Electroencephalography. 93.132.150.52 (talk) 11:56, 7 March 2010 (UTC)
- There is electrical activity in the brain - and where there is variation of electrical potentials, there are (inevitably) radio waves. However, the voltages are incredibly low and so are the frequencies - so those waves are incredibly, insanely weak - vastly too weak to make it past the skull - let alone any distance beyond that. Also, disentangling the results of a few billion neurons that are firing (seemingly) randomly is utterly impossible. The only way we have to pick this up is with sensors attached close to the scalp in the form of some kind of helmet - and even then, the signal strengths involved are on the lower edge of detectability. Because of the "firing all at once" problem, only the simplest information is obtainable in this way. We can pick up simple overall, slow speed activity this way (See: Electroencephalography).
- We should VERY clearly state, however, that we can't "receive" those waves in our brains. That's absolutely and utterly impossible. Firstly we have no radio signal reception sensors in our heads (if we did, we'd be totally deafened by the insanely high powered TV, Radio, Cellphone, etc signals that are shooting through us all the time!). Secondly, the signals involved are so incredibly weak that it would be impossible - even in principle to detect them at any distance whatever. Thirdly, there is no way to extract information from the cacophany of activity within those billions of neurons without having some spatial information. So telepathy without intrusive electronics is physically quite impossible.
- Having said that, an exceedingly crude form of telepathy has been implemented by Kevin Warwick (his article is worth reading). He has about 100 electrodes in an implant attached to the "median nerve" of one of his arms. A computer can measure nerve impulses that he sends that way...and he has demonstrated moving a robot arm using his mind alone. In a subsequent experiment, they implanted another set of sensors into his wife and they can now communicate by mentally activating their arm muscles and causing some kind of tingly sensation in the other person. It would be possible to learn to communicate (eg using Morse Code) by thought alone...but that's an exceedingly long way from simply "reading thoughts". This is more like a rather clunky wireless morse code transmitter that you have implanted in your body. However, "brain waves" aren't involved here - it's a conscious effort to transmit a 'tingle' and the resulting feeling is just like a tingle on the skin - not a mental image or speech or anything like that which might just "pop up" in your head.
- SteveBaker (talk) 22:24, 7 March 2010 (UTC)
“Mind waves” that can be used for “telepathy” may be said to exist after all ! (Note the quotation marks signaling unusual usage!)
Well, when you ask:
1. Is there any thing like mind waves?
2. Can a person just receive those mind waves?
3. What type of energy is it – are they really sound waves?
Then one might jump to the conclusion that what you are asking is: "Does telepathy (i.e. magical thought transferring) really exist?" As far as I know the answer to that question is simply:
"No! And the electromagnetic waves that do exist in the brain, may not (at least not yet) be used for any thought transfer resembling telepathy. So any belief in telepathy is mere superstition!"
BUT if one looks at those three questions from a slightyly different angle, interpreting: "any thing like mind waves" to mean: "anything that appears to work just as “telepathic waves” would work", then the truthful answers suddenly become:
1. Yes!
2. Yes! And it does not even require any training!
3. Yes they are surely a kind of sound waves!
Here it may be appropriate to repeat a quote which tend to pop up whenever people discuss magic, namely “Clarke's third law” which states that: "Any sufficiently advanced technology is indistinguishable from magic."
In this case, the advanced technology, that resembles telepathy, is the so called: "Directional loudspeaker" which makes it possible to direct sound from 5 meter (15feet?) away (or more?) towards one or two people in a crown, in such a way that nobody else in the crowd can hear any of it!
A few years back one popular-science television show had a story where they prooved that a hand-held directional speaker, located on a gallery at the side of the room, was powerful enough to play dance music to a dancing couple in front of a library reference desk, WHILE nobody else in the relatively silent library room could hear anything of the music! :-)
Unfortunately I do not have the exact reference to that story, but you may enjoy reading the article: "How directional loudspeakers work: An introduction to directional sound and how it's used in advertising, exhibitions, and the military." It is an explanation from ExplainThatStuff.com, in easy (not too scientific) language.
P.S.
Remember this, the next time you meet or hear of someone who "hears voices" in their head.
And be mindful of that maybe not all the prospective members of the "Hearing Voices Movement" (at least initially) are quite as psychotic or insane, as some mental health care workers would bet their reputation on that they are. Because, in fact, someone might just be playing a cruel trick on the victims – using directional speakers. 8-)
--Seren-dipper (talk) 00:04, 9 March 2010 (UTC)
Corrosion of copper
editDoes corrosion of copper involve esterification? —Preceding unsigned comment added by Kencankan (talk • contribs) 09:58, 7 March 2010 (UTC)
- You might want to read Organometallic chemistry. 93.132.150.52 (talk) 11:56, 7 March 2010 (UTC)
Cow pats
editCan methan be extracted from cow pats? Why doesn't the farmers collected the cow pats and instead of putting them on rose plants as fertilizer use them for methan production? —Preceding unsigned comment added by Firendofdarkness (talk • contribs) 10:52, 7 March 2010 (UTC)
- Yes, see :Anaerobic digestion. Collecting cow pats by hand however is labour intensive. It might be more economical to burn them as fuel. --Aspro (talk) 11:24, 7 March 2010 (UTC)
- Not generally "cow pats" as found on grassy ground where they are grazing - but the 'slurry' that comes from concrete areas where cows live and are milked, etc is increasingly used by farmers. They can scrape it up and pump the semi-liquid mix of cow poop and pee into methane-producing "digesters" that produce power for lighting and heating cow sheds. SteveBaker (talk) 22:03, 7 March 2010 (UTC)
pus-like sinus stuff
editWhat is the strong-smelling, pill-shaped puslike substance found in the sinuses? I know, that whole thing sounds horrible. --Chris (クリス • フィッチュ) (talk) 13:01, 7 March 2010 (UTC)
- We cannot give medical advice. Have you read the article Mucus and the truly disturbing article Dried nasal mucus? Edison (talk) 14:23, 7 March 2010 (UTC)
- How can pus be pill-shaped? Pus is a viscous liquid of sorts. DRosenbach (Talk | Contribs) 17:06, 7 March 2010 (UTC)
- It can be pill-shaped if it's enclosed in an abscess, perhaps? Either way, go to your medical practitioner to check it out. Regards, --—Cyclonenim | Chat 17:15, 7 March 2010 (UTC)
- How is it "found in" the sinuses? Cat scan? Surgery? Autopsy? Endoscopic exam? Or do you mean expelled by nose-blowing? Again, we will not provide diagnosis or medical device, but can discuss theoretical questions and refer a questioner to appropriate references such as Sinusitis, Rhinitis, Paranasal sinuses, or Pus. depending on how we, acting as reference librarians, understand the question. Anyone who thought they might have a sinus infection should consult a doctor rather than random people on the internet. Edison (talk) 23:08, 7 March 2010 (UTC)
- It can be pill-shaped if it's enclosed in an abscess, perhaps? Either way, go to your medical practitioner to check it out. Regards, --—Cyclonenim | Chat 17:15, 7 March 2010 (UTC)
- How can pus be pill-shaped? Pus is a viscous liquid of sorts. DRosenbach (Talk | Contribs) 17:06, 7 March 2010 (UTC)
- In the same geographical ballpark, and roughly pill-shaped and strong-smelling, are the tonsiliths. --Sean 19:39, 9 March 2010 (UTC)
Pineapple
editI want to grow a pineapple plant. Can I just cut the top off an existing pineapple and plant it? Will it grow into a pineapple bush? —Preceding unsigned comment added by Hawclawlaw (talk • contribs) 14:45, 7 March 2010 (UTC)
- I think pineapple seeds are in the lower portion of the fruit, in the interior of the fruit. I think they're pretty awkward to find in a pineapple you might have bought from the supermarket though as they're often removed. Regards, --—Cyclonenim | Chat 14:56, 7 March 2010 (UTC)
- Actually, the original poster has it right. However, it's only going to grow in tropical (and maybe subtropical) regions. StuRat (talk) 15:51, 7 March 2010 (UTC)
- It will grow in many places, but it will only fruit in tropical climates. --Tango (talk) 20:19, 7 March 2010 (UTC)
- Actually, the original poster has it right. However, it's only going to grow in tropical (and maybe subtropical) regions. StuRat (talk) 15:51, 7 March 2010 (UTC)
- A Google search threw this up for me, which seems to be what you're after. I can't tell you how accurate the site is, but it seems ok to me. Brammers (talk) 15:19, 7 March 2010 (UTC)
- Here's another interesting series of questions and answers about growing them. Scroll down to mid page for some good photos.Bielle (talk) 16:45, 7 March 2010 (UTC)
- They'll grow anywhere as a house plant, too. I've always wanted to grow one, have tried a couple of times but has never worked. Good luck! Aaadddaaammm (talk) 17:13, 7 March 2010 (UTC)
- Here's another interesting series of questions and answers about growing them. Scroll down to mid page for some good photos.Bielle (talk) 16:45, 7 March 2010 (UTC)
- Cut the top off with 1 inch of the fruit, plant in a very sandy soil mix, water sparingly. I've done in even in the UK - won't fruit, and won't survive any hint of frost. Ronhjones (Talk) 23:50, 7 March 2010 (UTC)
- I seem to recall that, if you want them to fruit, you need the soil to be warm as well as the air: I saw a really interesting programme a while ago(in the UK), about how rich estates grew pineapples in England before they could be imported. Anyone know what that programme would have been? Anyway, it seemed to involve undersoil heating, because using a heated greenhouse wasn't enough. You could always try... 86.177.121.239 (talk) 00:03, 8 March 2010 (UTC)
- I think it was the Victorian Kitchen Garden on the BBC. --TammyMoet (talk) 15:14, 8 March 2010 (UTC)
- I seem to recall that, if you want them to fruit, you need the soil to be warm as well as the air: I saw a really interesting programme a while ago(in the UK), about how rich estates grew pineapples in England before they could be imported. Anyone know what that programme would have been? Anyway, it seemed to involve undersoil heating, because using a heated greenhouse wasn't enough. You could always try... 86.177.121.239 (talk) 00:03, 8 March 2010 (UTC)
Oldest survival animal species?
editI would ask the oldest surviving species in general, but I assume someone would come back with cyanobacteria or something similar. I'm looking for the oldest surviving species in what today we consider to be in one of the major branches of animalia (e.g. mammals, fish, birds etc)? Regards, --—Cyclonenim | Chat 14:54, 7 March 2010 (UTC)
- Sorry to respond with a question, but to give a reliable answer I think we'd have to agree on the definition of Species, and how we would apply that to the available evidence. We cannot attempt interbreeding, nor can we sequence enough DNA from tissue recovered from an organism that lived (say) 100 million years ago and compare in the manner that might be required for certainty today. It's quite difficult to assign species-level taxonomy using fossils from many millions of years ago. Do you have a well-founded proposal for the definition to be used, before people start proposing candidate species? -- Scray (talk) 15:12, 7 March 2010 (UTC)
- Sorry, what I meant was are there any species around now that we know (from say, as you mentioned, fossil records) existed a long time ago, and which is the oldest? Clearly eukaryotic creatures are likely to have changed at least a bit in hundreds of millions of years, compared to say cyanobacteria which are remarkably stable. Regards, --—Cyclonenim | Chat 17:13, 7 March 2010 (UTC)
- I still don't think I've explained the issue clearly enough. For example, if we were to kill a Tree Swallow, retain only the bones, compress them a bit, and fossilize them, would we be able to confidently differentiate that fossil from a Golden Swallow? I only choose this as an example, to illustrate how specific a species designation is. Back to your clarification, then, how can we "know" that any fossil corresponds to an extant species? Fossils provide only some of the distinguishing characteristics. Your question is great, because it challenges us to think about what a species is. -- Scray (talk) 17:23, 7 March 2010 (UTC)
- So because our current definition of a species is two organism which can reproduce to create fertile offspring, that becomes irrelevant when looking at ancient animals because we have no method of studying whether their DNA is compatible? Not being an paleontologist I cannot answer you question, but presumably there are differences in bone anatomy between any two species, but I have no citation for that. If there isn't any difference physically, then clearly we would not be able to ascertain which is which. So is this search for the oldest known living animal pointless? I don't think so, since paleontologists clearly do know that, say, horseshoe crabs have been around for approximately 450 million years since the fossil record shows that the horseshoe crabs existing then are at least stupidly similar to the anatomy of those that are alive now. So, going on that method, which is the oldest surviving 'species'? Regards, --—Cyclonenim | Chat 19:36, 7 March 2010 (UTC)
- This is the Science reference desk, and I'm just pointing out that getting a good scientific answer depends on defining the question. You've got some pretty interesting answers already, but to weigh them (for the superlative "oldest" you seek) the question would need to be defined. I'm not criticizing you - from the start I thought that this raised an interesting challenge. -- Scray (talk) 19:49, 7 March 2010 (UTC)
- Sorry if you thought I was having a go, it wasn't supposed to come across that way. I think I just underestimated how complicated the question could be. Regards, --—Cyclonenim | Chat 22:02, 7 March 2010 (UTC)
- This is the Science reference desk, and I'm just pointing out that getting a good scientific answer depends on defining the question. You've got some pretty interesting answers already, but to weigh them (for the superlative "oldest" you seek) the question would need to be defined. I'm not criticizing you - from the start I thought that this raised an interesting challenge. -- Scray (talk) 19:49, 7 March 2010 (UTC)
- So because our current definition of a species is two organism which can reproduce to create fertile offspring, that becomes irrelevant when looking at ancient animals because we have no method of studying whether their DNA is compatible? Not being an paleontologist I cannot answer you question, but presumably there are differences in bone anatomy between any two species, but I have no citation for that. If there isn't any difference physically, then clearly we would not be able to ascertain which is which. So is this search for the oldest known living animal pointless? I don't think so, since paleontologists clearly do know that, say, horseshoe crabs have been around for approximately 450 million years since the fossil record shows that the horseshoe crabs existing then are at least stupidly similar to the anatomy of those that are alive now. So, going on that method, which is the oldest surviving 'species'? Regards, --—Cyclonenim | Chat 19:36, 7 March 2010 (UTC)
- I still don't think I've explained the issue clearly enough. For example, if we were to kill a Tree Swallow, retain only the bones, compress them a bit, and fossilize them, would we be able to confidently differentiate that fossil from a Golden Swallow? I only choose this as an example, to illustrate how specific a species designation is. Back to your clarification, then, how can we "know" that any fossil corresponds to an extant species? Fossils provide only some of the distinguishing characteristics. Your question is great, because it challenges us to think about what a species is. -- Scray (talk) 17:23, 7 March 2010 (UTC)
- Sorry, what I meant was are there any species around now that we know (from say, as you mentioned, fossil records) existed a long time ago, and which is the oldest? Clearly eukaryotic creatures are likely to have changed at least a bit in hundreds of millions of years, compared to say cyanobacteria which are remarkably stable. Regards, --—Cyclonenim | Chat 17:13, 7 March 2010 (UTC)
- If we go by animals that we would "recognize" as being similar to a modern species, how about the millipede, which goes back some 428 million years ? See Millipede#Evolution. StuRat (talk) 15:44, 7 March 2010 (UTC)
- The brachiopod genus Lingula comes pretty close, having been around for more than 500 million years, not sure about a species though. Mikenorton (talk) 16:51, 7 March 2010 (UTC)
- Theres Crocodile at 200 million years--Jac16888Talk 17:32, 7 March 2010 (UTC)
- Take a look at the Crocodile article - that's a Family designation; there are 2 sub-families, 5 major genera within one of those, and about a dozen species for the most common genus. The OP asked about species - are we talking about those now, genera, families, or just living things with bones that look kind of similar to some fossil? -- Scray (talk) 17:58, 7 March 2010 (UTC)
- Theres Crocodile at 200 million years--Jac16888Talk 17:32, 7 March 2010 (UTC)
- Like millipedes, the oldest known scorpion fossil dates to about 430 million years ago. A beautiful creature, that. – ClockworkSoul 17:59, 7 March 2010 (UTC)
- Tardigrade —Preceding unsigned comment added by TrialicWave (talk • contribs) 18:59, 7 March 2010
- If you're after animal species that are anatomically unchanged for several million years, then the living fossil article has several examples. 62.56.68.180 (talk) 01:20, 8 March 2010 (UTC)
- I've heard triops cancriformis called the oldest animal species known to still exist. 86.178.167.166 (talk) 01:03, 10 March 2010 (UTC)
Extra Life expectancy for the health-concious
editAre there any figures available for the extra life-expectancy of people who eat healthy foods, stay slim, exercise, do not smoke and seldom drink, compared with the average? Thanks 89.242.102.148 (talk) 16:14, 7 March 2010 (UTC)
- Yes. Basically the standard life expectancy models can be extended for this, by looking at specific countries. For example, in Africa or India it's unlikely that people will be drinking and smoking heavily while consuming vast amounts of fast food, whereas in the Western world those forms of consumption are very common.
- That sounds horribly imprecise. I'd expect health care access and capacity in the US, European nations, Africa, and India vary widely, among other things. I think a better study would be to talk to each region and ask individuals how much they pay attention to what they eat, how physically adept they are, and track people over their lifetime keeping this in mind. Mac Davis (talk) 19:21, 7 March 2010 (UTC)
- Unfortunately I think smoking is common or at least becoming commoner in many third-world countries, eg China, and they also often have much higher rates of fatal diseases such as AIDS, higher infant mortality, malnutrition, and deaths due to wars. So it would be difficult to find a Shangri-La like that. 78.146.208.26 (talk) 21:47, 8 March 2010 (UTC)
You'll be interest in things such as Life Tables and in general Actuarial science. I don't know the stats but as MacDavis alludes to location of the individual is a huge contributory factor. I'm sure someone will be able to link some stats but not got time myself. ny156uk (talk) 23:04, 7 March 2010 (UTC)
Telescope
editWhat is the difference between reflecting and refracting telescope? -- Extra999 (talk) 23:00, 7 March 2010 (UTC)
- The optical telescope article explains this, but basically, a reflecting telescope uses mirrors, and a refracting telescope uses lenses. CS Miller (talk) 17:41, 7 March 2010 (UTC)
- Or in simpler and more obvious terms; a reflecting telescope reflects light, while a refracting telescope refracts light to produce an image. —Preceding unsigned comment added by TrialicWave (talk • contribs) 18:46, 7 March 2010 (UTC)
- Not just any old mirror, but one ground into a parabolic shape. For a number of reasons, the largest "visual" telescopes in the world are reflectors. Radio telescopes such as the Very Large Array also use "reflection" to gather signals. ←Baseball Bugs What's up, Doc? carrots→ 20:25, 7 March 2010 (UTC)
- Curved, but not necessarily parabolic. Ritchey-Chrétien telescope designs use two hyperbolic mirrors, for example. And the Schmidt camera uses a spherical primary mirror, but also has a refractive corrector plate. -- Coneslayer (talk) 13:31, 8 March 2010 (UTC)
- Not just any old mirror, but one ground into a parabolic shape. For a number of reasons, the largest "visual" telescopes in the world are reflectors. Radio telescopes such as the Very Large Array also use "reflection" to gather signals. ←Baseball Bugs What's up, Doc? carrots→ 20:25, 7 March 2010 (UTC)
- Or in simpler and more obvious terms; a reflecting telescope reflects light, while a refracting telescope refracts light to produce an image. —Preceding unsigned comment added by TrialicWave (talk • contribs) 18:46, 7 March 2010 (UTC)
Intron question
editDo introns contain DNA from other species? —Preceding unsigned comment added by Celidia (talk • contribs) 18:22, 7 March 2010 (UTC)
- Depending on what you mean by "DNA from other species", they can. It's not at all clear where introns originated, but some have speculated that (at least some) introns are derived from transposons (mobile DNA elements). Certain transposons (especially some retrotransposons) are thought to be derived from viruses (like retroviruses) which infected a cell, and then lost the ability to construct infectious viral particles). Viruses which insert and remove themselves from the host chromosomal DNA have been known be "inefficient" and take a chunk of host DNA with them when they leave. - The scheme goes like this: a virus excises itself from the host DNA, taking a chunk with it. It then infects a different species (which, depending on the virus, is a relatively common occurrence), inserting the other species DNA into the genome. This inserted sequence, over a very long period of time, eventually loses it's infectivity, leaving the chunk of foreign DNA in the cell. However, while this scheme sounds plausible to me, I'm not aware of any specific examples of it. - You may also be interested in the topic of horizontal gene transfer, which is the general mechanism by which DNA of one species gets transferred to another. -- 174.21.235.250 (talk) 18:55, 7 March 2010 (UTC)
- And, in case you don't already know, our functional DNA also "contains the DNA of other species". We share over 98% of our DNA with chimps, for example. StuRat (talk) 20:24, 7 March 2010 (UTC)
Carbon planets
editOur article carbon planet says that the protoplanetary disc is carbon-rich and oxygen-poor. Why does it need to be oxygen-poor? Or, I suppose: What would happen if it was rich in both carbon and oxygen? Vimescarrot (talk) 18:41, 7 March 2010 (UTC)
- Presumably if oxygen was present, it would react with the carbon, forming carbon dioxide. As this is a gas, it wouldn't settle on the surface to form a layer. CS Miller (talk) —Preceding undated comment added 18:49, 7 March 2010 (UTC).
- And if by chance it did settle on the surface, it would cause rapid global warming because carbon dioxide is a greenhouse gas —Preceding unsigned comment added by TrialicWave (talk • contribs) 18:50, 7 March 2010 (UTC)
Thanks. I suppose what I really meant was, if it was oxygen-rich, why couldn't it still be a carbon planet? Why did Marc Kuchner think they need to exclude oxygen for it to be a carbon planet? Vimescarrot (talk) 19:37, 7 March 2010 (UTC)
- If it contained both lots of carbon and oxygen, like Earth, wouldn't it develop in a similar manner ? I think the point is that carbon only develops into diamonds and such in the absence of oxygen, which is why diamonds are rare, here on Earth, where such oxygen is plentiful. StuRat (talk) 20:19, 7 March 2010 (UTC)
- Okay...I think that answers it. Thanks. Vimescarrot (talk) 09:04, 8 March 2010 (UTC)
- You're welcome, and I've now marked this question as resolved. StuRat (talk) 10:18, 8 March 2010 (UTC)
Brain calories
editDoes your brain burn more calories when you're thinking hard? When does it burn more calories (stress?) and less calories (sleep?), and has this been measured? Mac Davis (talk) 19:23, 7 March 2010 (UTC)
- A rather brief and basic view of the brain's energy consumption during thought is given here. Let me know if it doesn't address your question. Regards, --—Cyclonenim | Chat 19:40, 7 March 2010 (UTC)
- The answer is that it burns more calories when active but not a lot more. Many popular accounts give incorrect information about this; here is a recent authoritative discussion. Looie496 (talk) 20:32, 7 March 2010 (UTC)
- (Original research/anecdote) Diabetics have reported greater blood sugar drop, a measure of metabolic rate, while they are asleep and having intensely visually detailed dreams with intricate plotting, compared to sleep without that extra brain work. Of course low blood sugar might have conversely caused the vivid dream images. Edison (talk) 23:24, 7 March 2010 (UTC)
- The answer is that it burns more calories when active but not a lot more. Many popular accounts give incorrect information about this; here is a recent authoritative discussion. Looie496 (talk) 20:32, 7 March 2010 (UTC)
Single source for printed label nutrition data and all or most UPC/PLC codes
editIs there an existing single source for food label nutrition data and UPC/PLC code besides this start-up site or better still a site where a cross reference to the codes used for the extensive USDA food nutrition database at http://www.nutrition.gov/ (where the site is down right now) and the UPC/PLC codes can be found? 71.100.11.118 (talk) 19:26, 7 March 2010 (UTC)
In-text citation and reference for textbooks and websites in scientific journals
editI searched for it but couldn't find instructions on the format for in-text and reference citations for textbooks and websites. I looked at different research papers to follow how they did it but it's hard to find one that cited textbooks or websites. Most papers only cite other research papers. —Preceding unsigned comment added by 70.68.120.162 (talk) 19:33, 7 March 2010 (UTC)
- Here's one for citing websites: [2]. Franamax (talk) 19:48, 7 March 2010 (UTC)
- And this should cover textbooks just fine, looking at the examples, several of them could be textbooks. Franamax (talk) 19:51, 7 March 2010 (UTC)
- Generally, biological journals use either the (Authorname, Year) format for inline citations or a number. There can be some variation from journal to journal. I suggest reading the specific journal's "Instructions to Authors" or similarly named page, usually linked on the journal's home page (e.g. Here are the ones from Cell and Developement both found under "For Authors" tabs on the main page). It will tell authors which style to use and may have Endnote stylesheets available for download (which can also be used by free reference managers, like Zotero - you need to use v. 2.0 to import Endnote styles.). If you are going to be writing articles for publication I strongly recommend using a reference manager. Changing inline citation formatting is a 1 or 2 click operation! -- Flyguy649 talk 20:05, 7 March 2010 (UTC)
- You could sign up for a free trial of RefWorks, import the book/site references you want, and see the product (you select the journal format). 30 days should be long enough to get a quick project done, or form a clear idea. Alternatively, have a look at our article on reference management software and try one of the open source products. Doing this by hand is so 20th century! -- Scray (talk) 20:39, 7 March 2010 (UTC)
Cyborgs
editHow close is science to having cyborgs similar to those in films and tv shows; ie a human whos organs are both organic and machine? —Preceding unsigned comment added by Heartofsand (talk • contribs) 21:23, 7 March 2010 (UTC)
- Very far away indeed from what you are probably imagining. But you have to define your terms. There are people walking around with artificial hip joints who are (technically) part man, part machine today. People have had false teeth for hundreds of years. Wooden "peg" legs go back even further. What percentage of man has to become machine before you attach the label "Cyborg"? SteveBaker (talk) 21:50, 7 March 2010 (UTC)
- Well, they did say "organs", by which I assume they mean to exclude bones and teeth. An artificial heart should pass that test, and we've had those, but they never really seemed to catch on. A pacemaker might qualify, and perhaps a cochlear implant and an insulin pump. There's also a type of implant for the blind. See artificial organ for more info. StuRat (talk) 22:04, 7 March 2010 (UTC)
- Bones and teeth are collections of different tissues serving a common purpose, so they are organs. The first sentence of bone seems to agree with me. --Tango (talk) 01:41, 8 March 2010 (UTC)
- Yes, but that's clearly not the definition the OP is using, and I don't think anyone would consider somebody with false teeth to be a cyborg. StuRat (talk) 09:01, 8 March 2010 (UTC)
- Exactly. So we can say that there are already plenty of "Cyborgs" in our society today - and have been for a long time. The problem is that this clearly isn't what Heartofsand is asking. "Similar to films and TV shows" is clearly something dramatically more than we're talking. So let's try to pick a couple of TV/Movie "Cyborgs". I guess at one extreme, we have something like "The Terminator" - which is pretty much all machine - but with organic skin. At the other, perhaps something like "The Million Dollar Man" - who is a regular human with a bunch of machine parts added. Clearly, if we can replace one hip joint, we could replace both of them - and probably a bunch of other joints too. But we can't replace all of the bones because bones are where things like blood cells are made and you'd die pretty quickly if we replaced them all. But there are certainly artificial hearts and all sorts of things like artificial limbs of varying kinds. But making someone who can run at 80mph is really out of the realms of possibility. Our implant technologies are almost all inferior to the original body parts. I can't think of anything we implant that doesn't need to be replaced after 20 to 30 years.
- The Terminator is a different problem. We might be able to grow skin and fat and figure out how to wrap them around a machine - but we can't build fully active, intelligent robots - we don't have the motor and battery technology - we don't have the AI capability. So forget the 'cyborg' angle - we can't build intelligent robots - so the whole wrapping them with skin thing is irrelevent.
- SteveBaker (talk) 04:33, 8 March 2010 (UTC)
- Regarding "implant technologies are almost all inferior to the original body parts": there's a debate over whether Oscar Pistorius' prosthetic legs give him an unfair advantage. Presumably as technology advances this will become a hotter issue. --Sean 20:18, 10 March 2010 (UTC)
- The main problem with building a cyborg is that you cannot easily mate the human nervous system with a machine "body"; and the human brain -- or at least the human mind, whatever part of the brain it is confined to -- is the key to being a proper cyborg. Now, cyborgs in sci-fi come in several flavors. "Terminator" - style cyborgs are not technically cyborgs, as they have no human parts to begin with; they are androids. So are the replicants in the "Blade Runner" and the type A7Mx in "Yokohama Kaidashi Kikō". Those are many tens of years away; maybe hundreds. "Ghost in the Shell" - style cyborgs are cyborgs with more and more human parts replaced by cybernetic devices, dealing directly with the Ship of Theseus issue of at what point a human is no longer human; YMMV. But this is also tens of years in the future. "Hacking the mind" may be further away yet, as the human brain does not internally use a deterministic code of any sort the way modern computers do (although motor commands to the muscles and sensory signals from the skin are pretty deterministic, or at least stereotypical). Taking a human head and spine (or head and torso) and mating them to a machine body, Darth Vader style, may be not that far away. Fairly advanced artificial limbs are available at present. Artificial hearts, lungs, and kidneys are also available, but not yet the easily portable ones. Artificial liver - not as far as I know, but maybe in a decade or two. Human liver can regenerate anyway, if the damage is not too severe. We'll see how fast this is going. The progress seems to have slowed down quite a bit now that we don't have the Cold War anymore, but hopefully it will pick up the pace again; maybe when cyborg building becomes commercially appealing. It may also be of interest to you that we actually have List of fictional cyborgs and articles on Cyborgs in general and Cyborgs in fiction in particular. --Dr Dima (talk) 04:24, 8 March 2010 (UTC)
F-ATPase
editHow is that pronounced? "ai, ti, pi, ase"? "ai, ti, pase"? "Adenosine Triphosphatase"? Thanks, 21:25, 7 March 2010 (UTC) —Preceding unsigned comment added by 89.139.173.179 (talk)
- It's pronounced /ɑː(ɹ)s/
- Whilst true, I suspect the OP wants a simpler answer. I've always said "ai-ti-pi, ase" and "adenosine triphosphatase" Regards, --—Cyclonenim | Chat 22:00, 7 March 2010 (UTC)
- Concur; it's always referred to as F--A-T-P-ase (the letters + -ase suffix). That's roughly pronounced /ɛf eɪ ti ˈpi: eɪz/. -- Flyguy649 talk 22:10, 7 March 2010 (UTC)
- Whilst true, I suspect the OP wants a simpler answer. I've always said "ai-ti-pi, ase" and "adenosine triphosphatase" Regards, --—Cyclonenim | Chat 22:00, 7 March 2010 (UTC)
measurement for light
editWhat is the measurement for light? I've heard people using candlepower, is that an official term? What constitutes one unit of candlepower? —Preceding unsigned comment added by Venture4356 (talk • contribs) 22:45, 7 March 2010 (UTC)
- If you mean brightness of light, that's called luminosity. Note that there's a difference between the total amount of light given off by an object and the amount which falls on any particular area. The unit candlepower is now largely replaced by the candela. There's also albedo, which is a measure of the reflectivity of a surface, and the frequency/wavelength (color) of light is often measured in THz or nM. StuRat (talk) 22:53, 7 March 2010 (UTC)
- There are many confusingly similar ways to specify the brightness or light output of a light source. While in the 19th century they referred to "candlepower" now they specify a light bulb output in "lumens" A candlepower was the brightness of a certain kind of "standard" candle, burning at a certain rate, but in practice the observed brightness varied widely between standard candles and in the same candle over time. One candlepower = 12.57 or 4 pi lumen per [3]. But the conversion is misleading: it assumes uniform output in all directions. Candlepower is the light emitted in a particular direction, so a bulb in a reflector would have more candlepower in the direction where the reflector concentrates it. Lumens integrate the light emitted in all directions,per [4]. A light source with a lens or reflector might have lots of candlepower in a very small angle, but not all that many lumens of total light output. The SI unit of luminous intensity is the Candela, selected to be about equal to the old "candle." Edison (talk) 01:51, 8 March 2010 (UTC)
Disulfide bond connecting two adjacent helices not connected by a loop/turn
editHow common are disulfide bonds that connect two adjacent helices which are not connected by a loop/turn? —Preceding unsigned comment added by 70.68.120.162 (talk) 23:18, 7 March 2010 (UTC)
- Not sure regarding the loops and turns bit, but disulphide bridges are pretty common. Regards, --—Cyclonenim | Chat 09:31, 8 March 2010 (UTC)
Talking parrots
editWhy is it that some species of parrot/cockatoo are better at mimicing human speech than others? Is there an anatomical or inteliigence reason? Something like an African Grey Parrot or an Amazon parrot is a very clear talker and sounds a bit like a human child speaking, wheras other species can talk - but their voices are basically just birdy squawks, tweets and growls shaped into words and syllables, or approximations of words and syllables.
Also - why is it that the Mynah is such a good mimic? It's even better than parrots, from what I've heard, despite not being a very intelligent creature. --95.148.104.245 (talk) 23:51, 7 March 2010 (UTC)
- It's not just intelligence that matters. An animal that can talk does need to be able to remember what it hears, but not all animals that are intelligent can talk (take Chimpanzees for example. The biggest factor of whether or not an animal can talk are the organs that make the noise and how they are arranged (see Speech production), so a human can never bark and a dog can never talk. --The High Fin Sperm Whale 23:58, 7 March 2010 (UTC)
- I should point out that the term "talk" is being used here to mean "mimic human speech". No animal actually talks, meaning using human speech fully (although they do communicate). StuRat (talk) 00:01, 8 March 2010 (UTC)
- OK - StuRat - you're going to have to stop guessing and saying that things aren't true without some evidence. We have articles Alex (parrot) and N'kisi that certainly show at least a strong possiblity that African Grey parrots can learn to use language "for real". "Fully" is a tough standard to meet - quite a few humans that I've met don't use the language "fully". But I've seen plenty of documentaries about Alex and he had me convinced. Several of the great apes have been trained to use sign language - complete with grammar, inventive use of signed speech, etc. It's OK to be wrong - but it's not OK to be persistently, annoyingly and definitely wrong. So how about you slow down your answers and actually do some checking and referencing before you jump to a negative conclusion. SteveBaker (talk) 04:13, 8 March 2010 (UTC)
- It's a bit rude to just accuse me of guessing. I've read several scientific journal articles and seen several documentaries of animal intelligence and specifically speech, and my answer was based on their conclusions. The sign language is an impressive form of communication (particularly in the case of Koko), but that's not speech, which our article defines as "vocalized human communication". They go on to define it as using a large number of words, typically over 10000. No animal uses anywhere near that many human words. Read our article and then tell me how, in any way, Alex or any other animal meets those definitions. Also, the question was about animal species capable of speech, which I take it means that most of the species is so capable, not just a rare exception. StuRat (talk) 08:33, 8 March 2010 (UTC)
- Simple English uses a vocabulary of just 1,500 words - Basic English just 850. You don't need anything like 10,000 words to communicate effectively. Koko knew 1,000 signs and 2,000 words - so she certainly managed "Basic English". Alex's vocabulary was small (150 words) - but could put them together to make composite words for things he didn't know the name of. Alex didn't know the name for an "Almond" - but, all by himself, he came up with "Cork nut" and used it consistently from that point onwards. Arguably, "Corknut" is another word - and one major problem with estimating vocabulary size is the degree to which prefixes, suffixes and composite words inflate the total. SteveBaker (talk) 04:48, 9 March 2010 (UTC)
- According to our article, Alex seemed to be limited to describing objects and answering simple questions about them. He seems to have had a very limited knowledge of verbs (the only one mentioned in the article that I can see is "go", used to say where he wanted to go). I think without a significant number of verbs you can't be said to be using language fully. --Tango (talk) 06:00, 9 March 2010 (UTC)
- Simple English uses a vocabulary of just 1,500 words - Basic English just 850. You don't need anything like 10,000 words to communicate effectively. Koko knew 1,000 signs and 2,000 words - so she certainly managed "Basic English". Alex's vocabulary was small (150 words) - but could put them together to make composite words for things he didn't know the name of. Alex didn't know the name for an "Almond" - but, all by himself, he came up with "Cork nut" and used it consistently from that point onwards. Arguably, "Corknut" is another word - and one major problem with estimating vocabulary size is the degree to which prefixes, suffixes and composite words inflate the total. SteveBaker (talk) 04:48, 9 March 2010 (UTC)
- And the apes that are taught sign language tend to "babble" quite a bit, meaning that there's a high degree of interpretation from their handlers as to what they're actually saying that's meaningful. I'm skeptical of how well they actually understand what they're "saying". I hadn't heard of Alex, who does appear to have learned a few (~150) words and actually communicate with them. See also Animal Language; it's not a cut and dried field. Buddy431 (talk) 21:53, 8 March 2010 (UTC)
- AFAICR Alex learned to respond appropriately to questions and instructions, in a way that indicated that he had some grasp of the meanings of the words; but I don't think he ever initiated verbal communication, did he? --ColinFine (talk) 23:56, 8 March 2010 (UTC)
- Sure he did. Read through the references in Alex (parrot) - you'll see plenty of occasions when Alex asked people to get him food and toys and such. SteveBaker (talk) 04:58, 9 March 2010 (UTC)
- AFAICR Alex learned to respond appropriately to questions and instructions, in a way that indicated that he had some grasp of the meanings of the words; but I don't think he ever initiated verbal communication, did he? --ColinFine (talk) 23:56, 8 March 2010 (UTC)
Chicken butt
editHello all. When I was little, my grandfather used to warn us that the qiao qiao (the back part of a chicken that sticks up) of a chicken would make us sick if we ate it, reasoning that the chicken stores its toxins there. I came across such a "qiao qiao" and that made me think of this again. I was wondering: Is there any scientific merit to this assertion? 68.76.146.111 (talk) 23:53, 7 March 2010 (UTC)
- Now, no doubt others will complain that I need to add detail, so here goes:
- 1) I doubt if we have an article on that part of the chicken. I don't know it's name, so don't know how to find it, if we do. And, even if we do have such an article, I don't believe it will address the issue of toxicity in any way.
- 2) Since chicken is a common food item, we would know if any part of it is toxic.
- 3) The tail of a chicken is there to hold tail feathers, not toxins. StuRat (talk) 00:10, 8 March 2010 (UTC)
- Of course there is an article, see Pygostyle, although it does not have the food properties, it is very fatty. Graeme Bartlett (talk) 00:39, 8 March 2010 (UTC)
- My mother, who introduced me to the terms Parson's nose and Pope's nose, said that it was bitter and unpleasant. This book and our article suggest many people disagree with her. 86.177.121.239 (talk) 00:58, 8 March 2010 (UTC)
- I added a redirect to fix the redlink on Parson's Nose. StuRat (talk) 01:10, 8 March 2010 (UTC)
Perhaps she was getting confused with the cloaca, which is where the eggs, feaces and urine leave the bird. Probably not the cleanest part of it. I think this is normally removed with the rest of the digestive systems when the bird is butchered. 62.56.68.180 (talk) 01:16, 8 March 2010 (UTC)
- The issue of toxins deserves address, as in ordinary language it usually represents an imaginary concept from the century before last. In its strict sense a toxin is a biologically produced substance that functions as a poison to other organisms. One of the mechanisms of disease theories of 19th century medicine was that a mechanism of illness could be the failure to eliminate endogenously produced toxins, leading to "autointoxication". Other 19th century mechanisms of disease included subluxation, miasma, masturbation, and evil spirits. There are two major organs that eliminate dangerous compounds produced endogenously or ingested (the liver and kidneys), and hence the only real diseases produced by autointoxication are the effects of liver or kidney failure. The other major diseases of toxins result from exogenous toxins such as botulism or mycotoxins. We can acquire bacteria (not toxins) from food that has been kept in unsafe conditions. We can acquire bacteria and viruses from feces of other humans, and occasionally from the fecal bacteria of other animals like salmonella from chicken or E. coli from beef. Uneducated people conflate cultural categories of "clean" and "unclean" food with food-borne illnesses. Scientists moved on from the old autointoxication theory in the early 20th century, but quacks and con men continue to find it very profitable to sell people ways to eliminate these imaginary toxins. alteripse (talk) 01:44, 8 March 2010 (UTC)
- I think that part of a cooked chicken used to be known as the parson's nose in Britain. 78.146.208.26 (talk) 20:52, 8 March 2010 (UTC)
- I assume he's referring to the gland just over the tail and not the tail itself. In the US, this gland is routinely cut out during processing because of its offensive odor/taste. Some cultures leave it in, so we can infer it's not too toxic. I've cut it out many times in a cargo cult fashion, as it looks unappetizing (like an overgrown pimple). --Sean 19:14, 9 March 2010 (UTC)