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August 14

Will scars ever be possible to remove/are they possible to remove?

Not seeking medical advice, and already looked up the wikipedia article on scars but it seems outdated. I was captivated by this story on the Extra-Cellular Matrix and how it helped regrow a man's finger with-out scar tissue.

Thanks. —Preceding unsigned comment added by 98.85.15.164 (talk) 01:05, 14 August 2010 (UTC)[reply]

Removed the OP's details about their scars. Sorry, I know you didn't mean to ask for medical advice, but we cannot comment on your specific case, and I don't want strangers on the Internet giving you false information and speculation about your scars when only a medical professional's word is accurate.--el Aprel (^facta-_facienda) 18:28, 14 August 2010 (UTC)[reply]

Per our article on scars, the American Association of Dermatology notes that no scar can be completely removed, though many can be considerably reduced. We cannot say whether or not perfect removal will someday be possible. — Lomn 02:02, 14 August 2010 (UTC)[reply]

Wikipedia has an article about Extracellular matrix. The OP does not identify which "this story" was but here is the BBC report (with video) of the finger recovery. Cuddlyable3 (talk) 08:17, 14 August 2010 (UTC)[reply]

See [1] for an old article about Renovo plc, one of many companies trying to reduce the activity that creates scars. Bear in mind that humans have an especially strong pathway (TGF-beta) to force scars versus forcing healing, for reasons not entirely understood. Wnt (talk) 00:47, 15 August 2010 (UTC)[reply]

Drug prices

What is the single most expensive drug per pill or shot in the US? What drug has the highest use cost per year in the US? Thanks! —Preceding unsigned comment added by 76.169.33.234 (talk) 05:05, 14 August 2010 (UTC)[reply]

From our article Eculizumab (trade name Soliris): According to Forbes magazine, Soliris, at $409,500 a year, is the world's single most expensive drug. --NorwegianBlue^talk 11:46, 14 August 2010 (UTC)[reply]

AIDS Question

How long can someone live who is on medication on average that has HIV that has developed into AIDS? The AIDS talks about how long if you ARE NOT getting treatment, but how long if you are? Also, are people who have HIV that has advanced to AIDS usually in the hospital? —Preceding unsigned comment added by 76.169.33.234 (talk) 05:16, 14 August 2010 (UTC)[reply]

Have you looked at our article on AIDS? It says there that 'HAART is thought to increase survival time by between 4 and 12 years'. HAART is the treatment you are talking about. I can't answer your second question, I'm afraid.--HarmoniousMembrane (talk) 09:58, 14 August 2010 (UTC)[reply]

Right, but I believe it is talking about going from HIV to AIDS. Then it goes to say that on average when someone who is untreated and has AIDS will live about 9.2 months. So I don't believe the article answers my question, but I could be wrong. —Preceding unsigned comment added by 76.91.30.156 (talk) 01:52, 15 August 2010 (UTC)[reply]

I think I recall the article saying the average survival length is about 10 years. However people who have AIDS generally don't die from it, rather they die from pneumonia or brain inflammation or cancer etc. ~A H 1^(TCU) 22:53, 14 August 2010 (UTC)[reply]

The nature of AIDS (which is to greatly diminish the immune system) means that sufferers die from other direct causes (like pneumonia) - but the root of the problem is the loss of their immune system. If someone is killed in a car crash, the actual cause may be that their heart stopped beating - but it's still the car crash that is to blame. Sure, people who have AIDS sometimes die of pneumonia - but they almost certainly wouldn't have gotten that disease if they didn't have AIDS in the first place. SteveBaker (talk) 00:46, 15 August 2010 (UTC)[reply]

Yes, Sorry. I interpreted that section wrong. My belief (Or at least what my PSHE teacher always told us at school), is that AIDS is when your immune system has been completely destroyed by HIV: i.e. you literally have no way of fighting off infections. I would therefore assume that if you want to survive as long as you can with AIDS, you need to be in as sterile an environment as possible: like a hospital (or something like the Bubble Boy lived in). . So I would guess, if you had full-blown AIDS, you would have to stay in a hospital, unless you wanted to die from any of the hundreds of minor infections our immune system deals with without us even noticing. —Preceding unsigned comment added by 92.8.250.168 (talk) 09:56, 15 August 2010 (UTC) Oops, that was me. I forgot to sign in, and sign my post!--HarmoniousMembrane (talk) 09:58, 15 August 2010 (UTC)[reply]

Well, the "bubble boy" approach would perhaps give patients a better chance of survival - but it's pretty impractical and not a pleasant way to spend what time people have remaining to them. But hospitals are full of people with diseases - and they are also places were drug-resistant diseases are most often to be found. If you have no immune system - then antibiotics are very important and drug-resistant diseases are a potential death-sentence. So keeping AIDS patients in hospital is also a really bad idea - at least while they don't have any serious infections. Also, it's not the case that your entire immune system is gone the instant you have AIDS, it's a progressive thing - I believe the formal definition of someone "having AIDS" is when the HIV virus has reduced their CD4+ T cell count to fewer than 200 cells per microliter (µL) of blood. At that point, the remaining T cells are still working to kill off invaders...but just not as effectively as in a normal person. SteveBaker (talk) 16:08, 15 August 2010 (UTC)[reply]

Yes, if you have a compromised immune system you want to stay as far away from hospitals as you can, while still receiving the best medical treatment you can! There was a big shift in treatment of cystic fibrosis some years ago, for example, when people realised it was a really bad idea to have children with CF meet up for camp-style holidays every year, and get treated in shared CF wards. Whoops. 86.164.66.83 (talk) 21:28, 15 August 2010 (UTC)[reply]

AIDS is a disease caused by HIV and defined using specific criteria developed by the U.S.A. CDC and various health agencies around the world. By current convention, once someone is diagnosed with AIDS, this diagnosis is not removed even if their condition (including CD4⁺ T cell count) improves. In part, this is a recognition that it's clear that not all of the immune system damage is reversed once someone has reached that stage and then improved; hence, clinicians often keep track of the nadir CD4 count. Nonetheless, someone with AIDS who is receiving combination antiretroviral therapy, has recovered their absolute CD4 count above 200 cells/mm³, and has an HIV RNA level below 50 copies/mL has an excellent prognosis as long as they continue to take and tolerate their medication well. Because effective combination antiretroviral therapy only became available in ~1998, we only have a little more than 10 years' experience, so any prognostication beyond 10 years involves extrapolation. Most experts anticipate that people receiving effective treatment for HIV can live many decades. I know people who had AIDS in the 1990s who are now working and feeling fine, except that they have to take medication every day without fail and they are having complications of aging (diabetes, hypertension, cardiovascular disease, cancer) much like the rest of us (though perhaps at higher rates, e.g. PMID 16107986). -- Scray (talk) 05:58, 17 August 2010 (UTC)[reply]

P.S. In response to the last part of the original question: most people with AIDS are not housed in hospital, regardless of geography or wealth. Most conditions associated with AIDS can be managed in the clinic until they reach the most severe stages; many are diagnosed and treatment is initiated during a hospitalization. -- Scray (talk) 06:04, 17 August 2010 (UTC)[reply]

Dwarf wheat

What is dwarf wheat? They were talking about it on TV and said that is was a very important invention, but there is no article or redirect. —Preceding unsigned comment added by 174.95.203.43 (talk) 06:07, 14 August 2010 (UTC)[reply]

A simple internet search should find things like Norman Borlaug#Dwarfing, [2] & [3] which should mostly answer your question. I'm doubtful this merits a seperate article so I've redirected it to wheat which also already contains some info on dwarfing, feel free to add more with references as appropriate Nil Einne (talk) 06:29, 14 August 2010 (UTC)[reply]

Bruegal's The Harvesters shows that wheat used to be nearly as tall as people. Some typical wheat I saw growing in a field in the UK recently was somewhat over a foot high. In past decades I recall seeing wheat about half this height, but have not seen any of that in recent years. Presumably modern wheat is dwarf wheat. 92.28.251.219 (talk) 12:34, 14 August 2010 (UTC)[reply]

Phase Diagram Topology

A typical phase diagram. The dotted green line shows the behaviour of substances like water (the minority) which expand on freezing.

Is there a finite set of phase diagram topologies? Are there any invariant properties of all phase diagrams? For example, are there any substances completely missing basic phases? Do they ever demonstrate fundamentally different phase layouts? -Craig Pemberton 07:57, 14 August 2010 (UTC)[reply]

There are certainly substances that break down chemically when heated and that prevents the existence of a liquid and/or vapor phase. I'm not sure if that is the kind of thing that you had in mind though. Dragons flight (talk) 08:18, 14 August 2010 (UTC)[reply]

So I guess some phase diagrams will be truncated. Of the states that "remain", can we still observe a consistent pattern or set of patterns? -Craig Pemberton 08:24, 14 August 2010 (UTC)[reply]

Helium has a unique phase diagram, in that there is no triple point and two liquid phases. Many susbtances display a variety of solid phases and there's no consistent pattern between these. But the generic phase diagram shown in the figure works for the vast majority of substances. Physchim62 (talk) 08:39, 14 August 2010 (UTC)[reply]

Looking at the phase diagram for Helium, it seems like you could achieve the same topology by drawing lines into the area of negative temperature and pressure. It's like Helium's triple point has fallen off the chart. Are there other exceptions of this nature? Are there other kinds of exceptions? 24.206.78.155 (talk) 09:08, 14 August 2010 (UTC)[reply]

Helium is also unique in having two distinct liquid phases, which is what "causes" the triple point to "fall off the chart" (not that negative pressure has any understood physical meaning, but to take your topological analogy). Physchim62 (talk) 18:29, 14 August 2010 (UTC)[reply]

There are general patterns of adjacency. In almost all cases (i.e., I can think of a few but only very few exceptions), at a given temperature, decreasing pressure goes from solid (possibly through several different ones) to liquid to gas, assuming each of those states exists at that T. Likewise, at a given pressure, increasing temperature goes from solid(s) to liquid to gas, assuming each exists there. That's just like saying "a solid melts when you cross its melting-point temperature" and similar general ideas of phase transitions. Well, except water and a few others whose volume-change at freezing is reversed. And some things likely have both a meta-stable solid (or maybe technically "glass"?) phase with low melting point and a highly crystalline solid phase with a high melting point. DMacks (talk) 09:15, 14 August 2010 (UTC)[reply]

What other exceptions are you thinking of? I am also wondering if the line of sublimation always begins exactly at the origin of the diagram. -Craig Pemberton 09:42, 14 August 2010 (UTC)[reply]

Assuming the lines are drawn as equilibrium lines (as is conventional for phase diagrams), then no, the line of sublimation does not always begin absolutely at the origin. To draw it like that is really just laziness, but it does also indicate that, for most substances, we have very little idea o phase transitions at very low temperatures and very low pressures. Physchim62 (talk) 18:20, 14 August 2010 (UTC)[reply]

I'm sure the set of possible phase diagrams is finite, but it may be pretty large. Consider for example the full phase diagram of water, as illustrated in this image. Looie496 (talk) 18:14, 14 August 2010 (UTC)[reply]

If you're going to include all solid phases, then I would say that the number of topologies is countably infinite (as is the number of possible chemical substances). If you limit yourself to pure substances and lump all crystalline phases together as "solid", then I believe that there are only a few known types of phase diagrams, and plenty of theory to explain why. Physchim62 (talk) 18:29, 14 August 2010 (UTC)[reply]

Okay, let's ignore any distinctions between the various forms of solids for any one material and just try to establish clarity for the basics right now. What are these few types of phase diagrams, and what is the theory which informs them? 66.112.225.248 (talk) 07:42, 15 August 2010 (UTC)[reply]

isn't science a religion?

Let's take one simple thing - the paradox. Obviously, scientists strongly believe that the actual, physical Universe cannot evince any paradox. Any "paradox" is in the mind of the weak, inept understander, who must change his mind about what he had thought about the Universe. But why do they believe this? They have a definition of the paradox, but believe strongly, I would say religiously, that the Universe can contain none. Granted it is a negative religious belief, different from believing in the existence of something. But isn't the belief of science in the non-existence of paradox just as religiously strong? 84.153.210.148 (talk) 09:45, 14 August 2010 (UTC)[reply]

The difference between science and religion is that the latter requires some sort of faith in something untenable, whereas the former requires evidence. I'm sure some philosopher will correct me, but that's always how I've defined the distinction. Regards, --—Cyclonenim | Chat 10:48, 14 August 2010 (UTC)[reply]

Yes, science is built on a constantly growing base of evidence, knowledge and information. For most religions, the evidence is fixed and unchanging, and unlikely to be acceptable to modern science. HiLo48 (talk) 11:02, 14 August 2010 (UTC)[reply]

neither of you addressed my specific point: scientists' views of paradox in the Universe. Namely, they take it on faith that there can be none, and any theory that would show one must be (ipso facto) flawed. How is this faith in the absence of paradox not religious? 84.153.210.148 (talk) 12:45, 14 August 2010 (UTC)[reply]

What makes you think that (all?) scientists think there can be no paradox? --VanBurenen (talk) 12:49, 14 August 2010 (UTC)[reply]

VanBurenen asks a good question. If unambiguous and repeatable experimental evidence of a "paradox" (whatever you mean by that term) is produced then science has to accept the reality of that evidence. Scientists then look for a new or extended theory that can accommodate and explain the new experimental evidence without contradicting other known facts. The results of relativity and quantum mechanics, were, at one time, regarded as "paradoxical" because they did not fit into the previously accepted theories of classical physics. "Paradoxes" such as the ultraviolet catastrophe, the photoelectric effect and the Michelson–Morley experiment were triggers for the development of new scientific theories. All science is based on the assumption that the physical world obeys consistent laws, but I don't think that is the same as "faith in the absence of paradox". Gandalf61 (talk) 13:10, 14 August 2010 (UTC)[reply]

Well, let's break this into two pieces:

1. Does science have preconceived notions? (Is the lack of paradoxes in nature just an assumption?)

2. Does having preconceived notions make something a religion?

As for #1 — obviously yes. The paradox example might not be a good one because arguably that is just a question of logic. But in any case there are many others. There are lots of deep-seated philosophical views that scientists have that they don't question and don't have any evidence for other than it makes sense. These are best seen in retrospect, when we look at scientists in the past, who make gigantic assumptions that we now think look quite odd, even though they were very smart people. Scientists are, of course, human, and it is very hard to see the philosophical assumptions that underlie one's whole life and profession, much less one's general society. A key point, though, is that the really brilliant and cherished scientists are the ones who can pull the rug out of such assumptions. Einstein is an icon because he was able to point, in a very specific way, at major assumptions about the nature of "time" and "space" and "measurement" that were being taken for granted by other scientists of his day, and show how they were not only wrong, but that with a more philosophically grounded approach, one actually ended up with a totally different physical theory, one that proved to resolve a number of problems with the previous theory. That's one of the nice things about science — it actually values (in the long run, anyway) being shown where its assumptions are trash.

As for #2 — I don't think so. What makes religion "religion" is not that there are some things which are not regularly questioned, that there are preconceived notions. Religions are a bit more complicated than that, a bit deeper than that. They are not just "things you don't question." (It is not a "religion" that I, say, am clueless or possibly wrong about what happens to the trash that I put out on the curb. It is not a "religion" that I think it looks better when I comb my hair than when I don't.)

Now, whether science has "religious" qualities (like faith, dogma, etc.) is an entirely valid question, but this isn't really the approach that will get you any good answers on that front, I don't think. In any case, my personal opinion is that while pointing to similarities between science and religion is a useful enterprise — it gets those of us who are so smug about our supposed greater connection to truth to come down a notch or two and admit that indeed, human knowledge is flawed — it does obscure some pretty important differences between scientific practices and religious practices, between scientific knowledge and religious knowledge. There is some overlap, to be sure, especially historically — but the really important aspects about both science and religious lie elsewhere, in my opinion. --Mr.98 (talk) 13:10, 14 August 2010 (UTC)[reply]

Another example could be found in the development of quantum mechanics, which defied all sort of regular logical precepts. In QM, things often happen without a reason; information can simply not exist sometimes where you would expect it to; time is a pretty complicated thing; things can sometimes be two things at once, etc. The fact that many of these discoveries violated all conventional, macroscopic logic, certainly did make them hard sells. But in the long run these kinds of "weird", "illogical" explanations actually worked out better than the "classical, logical" approach. Does the fact that people believed that the universe acted consistently causally, or that all information was theoretically knowable, make physics before QM a religion? Does the fact that they believe the opposite now make it a religion? It's the wrong question to ask, in the end. --Mr.98 (talk) 13:20, 14 August 2010 (UTC)[reply]

There are lots of things that scientists "take on faith", as you say. Most basically, that observations and experimentation can lead to accurate descriptions of the universe. If this were not true, then there would be no point in doing science (or theology, or pretty much any intellectual activity). Why should this be described as religious? Just because a belief is "religiously strong" doesn't mean it is a religious belief. I believe about as strongly as possible that Barack Obama is president of the USA, but that's not a religious belief. Staecker (talk) 13:16, 14 August 2010 (UTC)[reply]

The problem is in the definition of the word "paradox". It is by definition something that cannot be - something which is simultaneously both true and not true. The word implies something that cannot possibly be. If the word "paradox" meant "something difficult which can still be the truth" then we'd just have to invent a new word to mean "something self-contradictory that cannot be".

So this is not a case of scientists not being prepared to accept the possibility of there being actual, real world paradoxes - it's that when someone thinks they have found a paradox, we know that cannot (by the very definition of that word) be the case - so we have to look to see whether they are using the word incorrectly to describe something which can really be accepted as possible - or whether there was something they didn't understand that means that this wasn't really a paradox at all - or whether the laws of physics or some part of mathematics are making something seem paradoxical because those laws are incorrect in some way.

The latter situation is very interesting to science because it leads us to find errors in our laws - which is always an exciting and interesting thing! So when Gödel found a way to make a mathematical statement akin to the English phrase "This sentence is false." - this seeming paradox lead him to discover Gödel's incompleteness theorems that proves that there are statements in mathematics that cannot be proven to be either true or false (they aren't paradoxes though - they are things we can't discover the truth of - not things that are both true and false at the same time).

Accepting that something is a paradox is a typical religious reaction to a flaw in their belief system (eg: "Can God create an object so heavy that he cannot lift it?") - which is to try to bury the consequences and say "This is something mankind was not meant to know" or some similar bullshit. (Check out Omnipotence_paradox#Proposed_answers for some of the pathetic efforts to resolve this issue.)

A scientist has to find an explanation to discover why this is not, in fact, a paradox. So we might say "Well, the assumption that there exists a being that has absolutely no limits whatever is undoubtedly a paradox. So there must (by definition) be something wrong with our assumptions here. Either there is no such being - or the being is truly limited in what he can lift or in the maximum weight of object that he can create - or he lacks "free will" and that actively prevents him from choosing to create unliftable things - or to choose to lift things he previously created as unliftable"...and so on. A scientist might then go on to try to investigate which of those things is true (and in this case fail because there is an unfalsifiable hypothesis here).

But we are forced to deduce that either there is no God or God has at least one fundamental limitation that he cannot breach. Religions will accept neither of these possibilities - so they are forced into fluffy B.S answers like "accepting a paradox", which is about as reasonable as "Proving a falsehood" or saying that 1=0. You can't truly "accept a paradox" because the very meaning of the term is that this is something that cannot be accepted.

SteveBaker (talk) 13:33, 14 August 2010 (UTC)[reply]

I don't know if anyone'll see this, buried in the middle of this huge argument, but I have to object again to this characterization of the incompleteness theorems. The Gödel sentence of a foundationally relevant theory (say PA or ZFC) is not a "thing we cannot discover the truth of". The Gödel sentence of a consistent theory is true. It just can't be formally proved in that theory. But if you believe the theory is consistent (which presumably you do, or you wouldn't be using it foundationally), you must ipso facto believe that its Gödel sentence is true. --Trovatore (talk) 10:18, 15 August 2010 (UTC)[reply]

No. One can indeed "accept a paradox" (it's not beyond the capability of the brain to simultaneousy treat contradictory propositions as true). People quite routinely do. The result is normally some form of cognitive dissonance. The Rhymesmith (talk) 23:51, 14 August 2010 (UTC)[reply]

Sure, you can store the concept in your head - I'm thinking "1=0" right now - and so far, no major organs have exploded - but that doesn't mean it's true. If I can find a way to remove the paradox - then that's by far the best answer. There really aren't any solid paradoxes that can't be resolved in some satisfactory manner if we choose to open our eyes and reason our way through them. SteveBaker (talk) 00:41, 15 August 2010 (UTC)[reply]

There is a small difference: Science is the belief in the exstence of an (as of yet unknown) objective truth that you can then try to find using sound strategies (Occam's Razor and taking falsifiability of theories serious etc. etc.), while religion is based on the acceptance of dogmas that are most likely false. Count Iblis (talk) 14:38, 14 August 2010 (UTC)[reply]

This has already been well responded to, but let me add one more thing, in response to: Obviously, scientists strongly believe that the actual, physical Universe cannot evince any paradox. It's not obvious to me that one can say anything about scientists in general. I am friends with some scientists who believe all kinds of wacky things. And there are plenty of scientists who are also very religious--in the "spiritual" or "mystical" sense. There's no reason why a scientist can't believe the universe is fundamentally paradoxical at some level. Scientists are people. Their lives involve more than just doing science. Pfly (talk) 16:26, 14 August 2010 (UTC)[reply]

The only things integral to science that can even be close to being called a religion are materialism, Occam's Razor and current paradigms. Also look at dogma, spiritual dimension and quantum paradox. ~A H 1^(TCU) 22:50, 14 August 2010 (UTC)[reply]

I just want to add that I am truly tired of this continuous science/religion squabble. I know a lot of scientists and a lot of religious people, and it's clear to me that thoughtful people in both camps are all very interested in understanding the true nature of the world. They are interested in different aspects, of course - scientists are focused on the material world, while theologians are much more interested in the characterization of human existence - but for the most part they are complementary rather than opposed. This entire squabble is the result of zealots on both sides of the fence who are worried that the other side is trying to uproot their ontology. yeeee.... --Ludwigs2 23:07, 14 August 2010 (UTC)[reply]

I agree that it would be much better if we could "just get along" - but there are serious issues out there that mankind has to face which puts science and religion at opposite ends of important debates. When preachers start telling their congregations that (to pick an example) global warming isn't true - or if they to work to prevent the teaching of evolution, (preferring intelligent design) - then there is guaranteed to be conflict. So we are approaching a point where it is not simply possible to sweep the conflict under the rug and hope it'll go away. Sure, there are a few scientists who somehow manage to juggle both ideas in their heads at once - and there are plenty of religions who don't try to deny solidly proven scientific fact in order to promote their dogma - but those areas of overlap and tolerance are not enough. What flat out doesn't work is to say that we shouldn't discuss it because it upsets people. I'm sorry that you're "tired of it" - but that won't make the actual real issues magically go away.SteveBaker (talk) 00:41, 15 August 2010 (UTC)[reply]

I don't want to make the issues go way, I want to make the zealots go away. There are no real points of conflict to speak of; there are only a small population of religious advocates and a small population of scientism advocates shouting across each other about topics neither group understands properly. The division here is not between science and religion. the division is between people who use reason and people who don't, and the problem is that the people who don't use reason are inclined to be loud and obnoxious. --Ludwigs2 22:21, 15 August 2010 (UTC)[reply]

I would also like to point out that a few things have been sort of implicitly hinted at above. Objectivism is not a prerequisite for science. In fact, empirical skepticism is diametrically opposed to objectivism - that is to say, a scientist may choose to believe philosophically that (A). there is an objective truth in the world, and that the scientific method, applied to parse through observed data, is the best method to discern that objective truth; or (B). there is no objective truth, and the only relevant reality is that which we observe via experimental method and observation, so we construct a scientific method to "float" on this sea of observations to help us make sense of it. These are totally different fundamental world-views - yet both are capable of sustaining the same scientific methodology and stringent experimental validation to discern and describe a "reality" based on experiment.

Furthermore, I think the assumption that "paradox does not exist" is weakly-defined. If I understand the OP's insinuation, what they mean to say is that "scientists must accept on faith that the universe is consistent and predictable." This is not a requisite for using the scientific method to make sense of the universe. This is a particular world-view, and it happens to be the more effective world-view (because, to date, we have never observed any serious inconsistencies with our universe - gravity hasn't shut off; the Earth hasn't stopped spinning; and so on). One can make a serious and legitimate argument that there is a "faith-based" assumption about this consistency. Most scientists accept "on faith" that the laws they discover today will continue to be valid tomorrow. Most scientists would probably clarify that if the laws changed from day to day, the universe would be "paradoxical" - and then they would note that they do not seem to observe that strange behavior, and therefore conclude that it is not the case. Now, if all this is said, and we concede the point that a belief in a consistent and predictable universe is a belief, and not a fact, all is not lost - we don't need to start publishing flying spaghetti monster experiments in Nature just yet - because the scientific method has one more tool: Occam's razor. Not all "faith-based" beliefs are equally improbable. A belief that the universe is consistent is intrinsically simpler than a belief that the universe changes from day to day. (There's nothing to explain if nothing changed!) And scientists typically prefer simple explanations. If every day, the parameters for the laws of gravitation changed, we'd have a lot of figuring-out to do, in order to deduce a reason and characterize the ways that these laws changed. So, while consistency is impossible to prove, (arguably, it must be accepted on faith), it's still the better explanation for the universe than inconsistency.

To go even deeper in to the realm of the philosophical, there is one last detail of the scientific method that is also accepted "on faith": causality. This is the "assumption" that "things affect other things." If we want to dive deep into the humanities, there have been discussions about causality dating back to at least Aristotle's primum movens discussions; and for obvious reasons, this issue has been corresponded to a religious context by theologians (though originally, Aristotle's discussion had absolutely nothing to do with god, a god, or any sort of deity - it was purely a secular philosophical question about cause and effect). But there is an assumption in the scientific method that cause is related to effect. This is such a stupidly simple assumption that it takes a very large amount of psychodelic ... thinking... to try and break it. It is very hard to conceive of a universe where cause does not relate to effect; but it is exactly this principle that we can never prove exists, and we must rely on entirely, in order to make the scientific method work. The scientific method uses controlled experiment, with the assumption that repeated experiments will behave consistently, in order to reduce and simplify explanations of cause-and-effect. But if there is no relationship - if we live in a purely random and chaotic world, where particles do not interact and every state of energy and matter in the universe is completely uncausally related to any previous or future state, ... the scientific method has nothing to show or deduce. If we break causality, then consistency is irrelevant.

So, yes, there are some fundamental, deep assumptions in the scientific method: scientists believe that the universe is consistent in the ways that things cause effects. These are pretty solid, easy-to-accept assumptions: I challenge you to come up with any reasonable philosophy that does not make these assumptions. They are such reasonable, simple, and fundamental assumptions: Things exist; they affect other things; and we can explain how by observing them carefully. With those very simple assumptions, you start running and end up with all of science as we know it today. These assumptions are not sufficient to qualify scientific thought as a "religion." Nimur (talk) 06:36, 15 August 2010 (UTC)[reply]

On causality, it is of note that at various times, the notion of what causality even means — precisely — or if it holds at all has actually been perfectly within the realm of scientific research. Modern physics is full of redefinitions and even occasional abandonment of causality in favor of statistical explanations. All of this is just pointed out to illustrate that the system is quite, quite flexible — it can question its own underpinnings quite readily, once it has reason to. --Mr.98 (talk) 15:23, 15 August 2010 (UTC)[reply]

Occam's razor isn't a true part of the scientific process. You cannot say "This is definitely true because Occam's razor says so". It is, however, a useful and powerful general guideline. If we cannot prove whether hypothesis A or hypothesis B is true - then presuming that the simplest of the two is true is very often the best course of action. Is it possible for pink piano-playing aardvarks to exist on the far side of the moon? Yes, it's definitely possible. Should we design a spacecraft to go out and look for them? Hell no! Occam's razor says that's a really stupid idea! However, the razor can be wrong. If I give you the number series "1,2,3,4,5,6" and ask you for the next number in the series, you should realise that mathematically, there are an infinite number of possible answers. Occam's razor says that '7' is the best choice because x_n+1=x_n+1 is the simplest possible mathematical expression that produces the data we've been given. Sadly, I was thinking of numbers that are factors of 60 and the next number in the series happens to be '10'...Occam's razor failed us - but in the absence of any other data, it was still by far the best/most-likely choice. People unconsciously live by Occam's razor all the time in their daily lives. We do not behave as if every closed door has a ravenous tiger hiding behind it...although that is certainly a possible explanation for why nobody has come out of that door in the last 5 minutes, we prefer the simpler hypothesis that nobody came out of the door because they had no need to.

Occam's razor isn't like a religious belief to be taken on blind faith. Scientists are (or at least should be) aware that it's only a rough guideline - and that we should always be prepared toss out it out whenever better evidence comes along. It is certainly interesting that nature does seem to prefer simple solutions - and it's amazing how often the razor produces the right answer - but it's far from a dogmatic belief. SteveBaker (talk) 15:44, 15 August 2010 (UTC)[reply]

When you argue about whether a paradox can exist - you are merely debating the definition of a word. If you conclude that the linguistic definition of "paradox" is such that paradoxes can exist - then we need a new word to describe a condition which cannot exist because (for example) nothing can be both true and false at the same time, or because 1 cannot equal 0 or whatever. If you go on to claim that things can indeed be both true and false at the same time - then we need a new definition of the words "true" and "false" - and so forth. So, presuming the "normal" definitions of such words, paradoxes cannot exist because the word is used to define things that cannot exist. When we say that "There exists an immovable object and an irresistable force" - then the consequence of that assertion is a logical impossibility - this statement cannot be true - so it is definitely the case that either there are no immovable objects or there are no irresistable forces or that neither exist. I'd like to use the word "paradox" for such things - but if you'd prefer a weaker definition of that word then we just need to agree on a new word that I can use in order to phrase this discussion.

The things I'm talking about (like "God exists and has no limitations whatever" - or "This sentence is false") need a word that means "impossible for reasons dictated by mathematical/logical rigor" - and that word is "paradox". That kind of paradox cannot (by the definition that I'm choosing for that word) exist. All cases of seeming paradoxes must therefore have some kind of flaw that results in them either turning out not to be paradoxes at all (like "Which came first - the chicken or the egg?") - or which turn out not to be "correct" (like: "let x=0 therefore x(x-1)=0 therefore x-1=0 therefore x=1 therefore 1=0"). Finding that flaw is sometimes tricky - but it is inevitably present. SteveBaker (talk) 15:13, 15 August 2010 (UTC)[reply]

From the OED, "paradox": first definitions are obsolete, then we get: "An apparently absurd or self-contradictory statement or proposition, or a strongly counter-intuitive one, which investigation, analysis, or explanation may nevertheless prove to be well-founded or true." Then, "A proposition or statement that is (taken to be) actually self-contradictory, absurd, or intrinsically unreasonable." Then, "Logic. More fully logical paradox. An argument, based on (apparently) acceptable premises and using (apparently) valid reasoning, which leads to a conclusion that is against sense, logically unacceptable, or self-contradictory; the conclusion of such an argument. Freq. with a descriptive or eponymous name." Then follows a bunch of more specialized, jargony definitions. My point here is that a number of people above are defining "paradox" to have a strictly, more "strong" meaning than the OED's definition. The OED's definitions do not suggest that paradoxes are by definition impossible. On the contrary, the very first non-obsolete/archaic definition explicitly defines paradox as apparently self-contradcitory but in fact "well-founded or true". This is the way I have long used the word: A paradox is something that seems impossible but actually happens. We have plenty of words for things that are impossible. The word "paradox" is more subtle, I have long thought. I realize I am arguing over semantics, but this is the reference desk, so I refer you to the OED. Pfly (talk) 11:07, 16 August 2010 (UTC)[reply]

We can certainly take this weaker definition - but then consider the OP's original question, rephrased with the weaker definition: "Obviously, scientists strongly believe that the actual, physical Universe cannot evince any apparently absurd or self-contradictory thing. Any "apparently absurd or self-contradictory statement" is in the mind of the weak, inept understander, who must change his mind about what he had thought about the Universe. But why do they believe this?". Do we really think that's what the OP is asking? Well, if so, the question is patently unfounded - scientists are well aware of things that are merely apparently absurd...the quantum and relativity theories are stuffed to the brim with apparently absurd/self-contradictory things - particles are simultaneously waves - 100mph+100mph doesn't make 200mph - gravity changes time! The OP's question only makes sense in the context of the strong definitions of the word. Hence my position that paradoxes (of the kind the OP is talking about) are impossible by definition. SteveBaker (talk) 23:15, 16 August 2010 (UTC)[reply]

Darksucker Theory

Hello Everyone. A few years ago, I remembered reading in the New Scientist 'Last Word' section a reply (I think for a question about why light bulbs turn grey over time), that light bulbs do not emitt light, but suck dark. It sounded very fishy, but I forgot about it. Recently, however, I was thinking about it again, and wanted to know the full theory. I did a google search and found this, which explains the full theory. To be honest, it seems to be phrased as a joke; but I was wondering what exactly means it is BS. I thought of two reasons:

1.Dark cannot travel faster than light, as it would violate casuality per Relativity 2.Light has been shown to be Photons/EM waves, depending on curcumstances, not some Field that is revealed when dark is removed.

Any more reasons why this theory cannot be true? (I know it probably isn't, but I would like some concrete reasons). Thanks for any answers. And incidentally, it was startling, when I put 'Darksucker' into the search bar, to be returned with 'Do you mean 'dicksucker'!--HarmoniousMembrane (talk) 09:52, 14 August 2010 (UTC)[reply]

first of all - maybe you were signed in, and Google knows you all too well? Second, you can see even just a few photons with your naked eye, and we have machines that can emit photons (particles of light) one by one, so obviously "sucking dark" is a joke. The punchline is, that's why when an incandescent lightbulb "goes out" you can see the filament turns black (or even releases smoke): it's sucked all the dark it can. 84.153.210.148 (talk) 10:13, 14 August 2010 (UTC)[reply]

Yes, that's a good point, about devices that can produce photons one at a time. I can remember Feynman mentioning them during one of his online lectures: what are they callled? And I wouldn't have been surprised if google did it, but I was talking about the wikipedia search bar!--HarmoniousMembrane (talk) 10:39, 14 August 2010 (UTC)[reply]

The New Scientist's 'Last Word' page is a question and answer section much like this Ref desk, and sometimes deliberately includes joke answers if the joke is good enough, although the assuption is that readers will not really be taken in by it. Much humour can be extracted from treating abstract concepts, and absences or deficiencies of actual entities, like dark (absence of light) or cold (relative deficiency of heat), as entities in their own right (there's a special word for this, which I've momentarily forgotten - anyone?). Terry Pratchett often deploys this tactic, and has argued that (at least on the Discworld, where light is slowed to near-sonic speeds by the intense magical field) dark must be faster than light, because it has to be able to see the light coming and get out of the way in time. 87.81.230.195 (talk) 12:16, 14 August 2010 (UTC)[reply]

You cant suck dark as darkness is simply the absence of light. —Preceding unsigned comment added by 195.89.16.154 (talk) 12:47, 14 August 2010 (UTC)[reply]

As I understand it there are no evidence against a theory where photons are a hole in a field of darknes analogous to electron hole in a semiconductor but as long as it does not explain more observations than the theory that a photon is a elementary particle it fails Occam's razor. --Gr8xoz (talk) 14:46, 14 August 2010 (UTC)[reply]

Was the original New Scientist column published around the the start of April by any chance? Equisetum (talk | email | contributions) 21:54, 14 August 2010 (UTC)[reply]

Just for the record, "dark", being the absence of light, travels at the speed of light. If a star twenty light-years away suddenly stopped shining, we would see the light "go out" twenty years later, give or take. When a light bulb is turned on, the "dark" would travel away from the light rather than be sucked into it. ~A H 1^(TCU) 22:45, 14 August 2010 (UTC)[reply]

just for another reason, 'dark sucking' would play hell with various laws of conservation. where would all this sucked darkness go? a candle, for instance, would have to grow in length to store all the darkness it's sucking, and a light bulb would eventually collapse into a black (or white?) hole. but since these don't happen, you'd have to create a whole new set of theories about how darkness has negative volume/density (i.e., the more darkness something contains, the smaller it is, until the object reaches its maximal darkness capacity and disappears). --Ludwigs2 23:18, 14 August 2010 (UTC)[reply]

On printed circuit boards and schematic diagrams, incandescent bulbs (such as indicator lights) are abbreviated "DS", much as resistors are abbreviated "R", capacitors "C", inductors "L", and diodes "CR". ("L" is used as a symbol for inductance and "CR" stands for "crystal rectifier", but I don't know the origin of "DS". Is there a WP article on this?) I have always assumed that the phrase "dark sucker" was chosen to match the abbreviation. -- 1.47.99.181 (talk) 00:34, 15 August 2010 (UTC)[reply]

Apart from any comedy about light bulbs turning grey, see transactional interpretation. Light detectors emit "dark" as an advanced wave moving backward in time. Wnt (talk) 00:29, 15 August 2010 (UTC)[reply]

MTech in IITs

Hi I am from Hyderabad. I want to do my MTech from IITs but my aggregate is less than 60% in my BTech. But in IIT Madras website I saw the minimum qualification is a degree and GATE score http://gate.iitm.ac.in/mtechadm/gelig.php Can I get the admission if my GATE score is good?? —Preceding unsigned comment added by 115.109.194.75 (talk) 11:52, 14 August 2010 (UTC)[reply]

Not this year, because IIT Madras is full for its M.Tech. courses! You really need to ask the IIT itself if you want to know how they treat candidacies: note that they might change requirements from year to year, so don't rely on the 2010 rules being valid for 2011. Physchim62 (talk) 18:44, 14 August 2010 (UTC)[reply]

^^^How can you say that actually??? —Preceding unsigned comment added by 115.109.194.75 (talk) 12:55, 16 August 2010 (UTC)[reply]

student directories

where can i find past copies of student directories with addresses so i can re connect with old classmates —Preceding unsigned comment added by Tomjohnson357 (talk • contribs) 16:01, 14 August 2010 (UTC)[reply]

We're going to need a LOT more information - like which school you went to and in what years. A good place to search for people like that (if you don't have any more specific place) is http://www.linkedin.com SteveBaker (talk) 16:04, 14 August 2010 (UTC)[reply]

would my old school give me their addresses? —Preceding unsigned comment added by Tomjohnson357 (talk • contribs) 16:46, 14 August 2010 (UTC)[reply]

Only your school could answer that question. DMacks (talk) 17:13, 14 August 2010 (UTC)[reply]

Old student directories would be of little use unless you are a recent graduate, since people move. You might see their parents address and get the current address from them if it hasn't been too many years since the directory was issued. Some old college directories are for sale from time to time on Ebay. Classmates.com exists to connect you with old high school or college classmates who wish to be contacted. Facebook has "groups" of alumni from many colleges and highschools, without the high subscription fees Classmates demands. Some colleges have alumni internet sites where you can email classmates who have also joined. Some schools demand you pay to join the alumni association. It is possible to use internet people finder services, which (possibly for a fee) will find just about anyone, but your old classmates might see you as a stalker if it is clear you spent a lot of time and money tracking them down. If the old classmates have websites, like for business, or Facebook pages, it seems natural enough to drop them a friendly note. Edison (talk) 20:04, 14 August 2010 (UTC)[reply]

Try searching their names on Facebook. ~A H 1^(TCU) 22:42, 14 August 2010 (UTC)[reply]

Looking for old classmates has become a tricky area on the Internet. There are some sites that purport to help with this task but which are more spam sites than real directories. As for the old school helping, privacy requirements will often get in the way of this, but the old school may be wiling to pass your details on to others so that they may contact you. HiLo48 (talk) 23:08, 14 August 2010 (UTC)[reply]

If an icebreaker hit the iceberg that sank the Titanic...

Would it survive without any problems? ScienceApe (talk) 17:18, 14 August 2010 (UTC)[reply]

I would think so, as icebreakers are designed for such tasks and are designed to have hulls much more powerful than the Titanic. Tyrol5 [Talk] 17:43, 14 August 2010 (UTC)[reply]

Icebreakers are designed to break through sea ice -- which is relatively soft -- up to a given thickness. They aren't designed to hit massive icebergs of the sort that calve from glaciers. Looie496 (talk) 18:03, 14 August 2010 (UTC)[reply]

True, but I would think that it would stand a better chance than an early twentieth century steamer would. Tyrol5 [Talk] 18:44, 14 August 2010 (UTC)[reply]

The titanic would have survived the iceberg had it hit it head on - it was the sidewise hit and extended damage down the side of the hull that did it in. An icebreaker would likely suffer the same fate, though it might be a little more resistant. Icebreakers are designed to use their bow weight to crack ice, not to bash through it like a chisel, so I doubt they are extensively reinforced down their sides. --Ludwigs2 23:24, 14 August 2010 (UTC)[reply]

It depends a lot on how the hit occurred. The Titanic iceberg was described (and photographed) as a "large" iceberg. "Large" (in this context) is actually a technical term used by the International Ice Patrol for a berg roughly 45–75 metres high (above water) and 120–200 metres wide. Since icebergs only have 10% if their total height above water - we could estimate the total volume of this one as about a million cubic meters - hence weighing in at about a million tonnes.

A modern icebreaker (let's pick the USCGC Healy as an example) weighs just 16,000 tonnes. Running into an iceberg weighing 60 times more than the ship is a lot like hitting an immovable object. The worst-case energy released by a 16,000 tonne vessel moving at (let's say) the top speed of the Healy (30kph - roughly 8meters/sec) and coming to a dead stop would be considerable: mv² is 16x10⁶kg x 8² ms^-1 is 10⁹J - which is an ungodly amount. Enough energy to completely melt a ton of steel for example! More than enough to make a considerable mess of an icebreaker. The difficult question is what fraction of that energy would be transferred to the iceberg and what fraction to the ship - but it's pretty clear that the worst-case impact would not be survivable.

However, the impact with the Titanic was a glancing blow. The Healy has most of her heaviest plating at the bow and stern and within one meter of the waterline - and she has a double hull and stiffer internal ribbing in those areas. The hole in the Titanic's hull was more than a meter below sea level - so that thicker steel closer to the waterline wouldn't help the icebreaker much. The Titanic has steel plates between an inch and an inch and a half thick - but it was of a type of steel that became brittle in those cold ocean temperatures. The Healy uses a special type of steel that doesn't suffer from that problem - but it's nothing like as thick that far below the waterline.

CONCLUSION: As you can tell - this isn't a simple call. The double-hull design of a modern icebreaker would certainly help a lot - but I'm personally skeptical that it would be enough. A head-on impact produces a lot of energy - but on the strongest part of the ship - a Titanic-like impact happens on parts of the icebreaker that aren't specially reinforced - but the double-hull might be enough to save her from sinking. Perhaps the biggest saving grace is that the radar and satellite links available to modern ships of all kinds should allow them to completely avoid iceberg impacts in the first place - and that's probably the best answer here.

SteveBaker (talk) 00:18, 15 August 2010 (UTC)[reply]

Regarding the Titanic (which had a tonnage about 3 times that of the Healy), I just looked over some of the testimony given in the Inquiry. One of the design engineers testified that he believed the Titanic would have survived a head-on collision because the first 100 feet of the ship would have crumpled and cushioned the blow for the rest of the ship. However this same engineer testified that he did not believe the ship could have broken in two shortly before it sank, which as I understand it is now conclusively known to have happened. In any case it's not as if the ship could have got off without injury. Looie496 (talk) 01:03, 15 August 2010 (UTC)[reply]

Yep - that's what I'd heard too. The damage to the bow of the Titanic would have been extreme. The ship could stay afloat with as many as 4 compartments full of water - but the damage to her side breached 5 of them. If a head-on collision would have damaged less than 5 compartments, it might have saved her and it seems perfectly possible that she would have at least remained afloat long enough for adequate help to arrive. However, it's hard to imagine the captain of the Titanic being congratulated for deliberately ordering his crew to slam his vessel headlong into an iceberg. After all - if they'd managed to turn just maybe ten feet more to the left, they wouldn't have suffered so much as a scratch and the whole event would have been considered to be a masterful stroke of seamanship. The root cause here was pushing on speed where caution was needed. Had she been sailing at a speed appropriate for the visibility and known presence of icebergs, that would have been an easy escape. The many design and construction flaws in the ship herself would never have been a problem. Anyway - this is getting off-topic. The question is about icebreakers - and they aren't built in the same way as the Titanic so the conclusions would be quite different. SteveBaker (talk) 03:13, 15 August 2010 (UTC)[reply]

Well, I thought it was interesting that the reason the Titanic might have survived is that it was not built like an icebreaker. If it had the rigid bow of an icebreaker, the whole ship would probably have disintegrated in a head-on collision -- there's no way 50,000 tons is going to stop on a dime, and the iceberg wasn't going to get out of its way. Looie496 (talk) 05:27, 15 August 2010 (UTC)[reply]

As a minor clarification, I've just been reading the articles in response to this topic and as far as I can tell it was the first officer not the captain who was in command when the iceberg was spotted, the captain I guess asleep or trying to sleep Nil Einne (talk) 10:49, 15 August 2010 (UTC)[reply]

I'd have thought it reasonably likely a strong ship like an icebreaker would survive hitting an iceberg by gouging a big hole in it. I've twice seen docks destroyed by ships bashing into them, one made a huge hole 30 feet into the concrete and earth that reached the road behind. Dmcq (talk) 11:42, 15 August 2010 (UTC)[reply]

Here's a quote from John Jenner, the captain of Canada's largest icebreaker, taken from this web page: Question: What problems do you have with icebergs when you’re icebreaking? Answer: Although we’re built to break ice, if we were to collide with an iceberg at a certain speed it would certainly do damage. When you have an iceberg you have all types of little pieces of it breaking off, and they’re very hard. When we’re manoeuvering and laying out course lines and we know there’s a ‘berg, we will pass on the side that we know is clear. You also have to keep in mind that seven-eighths of an iceberg is under the water so you can’t just come right up to it ― you have to give yourself some distance. So we slow down at night and when the concentration of icebergs increases because we have to keep track of them. Looie496 (talk) 16:51, 15 August 2010 (UTC)[reply]

Measurement system used by the US Military

Does the US Military use the regular or metric system? --70.134.48.188 (talk) 20:58, 14 August 2010 (UTC)[reply]

The answer appears to be that they use mostly metric (to avoid confusion when working alongside allied forces), but with some exceptions. See Metrication in the United States#Military. —Preceding unsigned comment added by Equisetum (talk • contribs) 22:02, 14 August 2010 (UTC)[reply]

Do they use nautical miles and knots? ~A H 1^(TCU) 22:41, 14 August 2010 (UTC)[reply]

Nautical miles have been internationally agreed units (1 NM = 1,852 metres) since 1929 Alansplodge (talk) 15:00, 15 August 2010 (UTC)[reply]

"regular" is called imperial--92.251.230.132 (talk) 01:17, 15 August 2010 (UTC)[reply]

By using the word regular. our questioner shows the unfortunate but typical US-centrism of many who post here. Only two other countries (which most Americans would prefer to not be seen to be aligned with) have failed to officially metricate. So regular in most of the world means metric. As for it meaning imperial in the USA, that's wrong too. It's United States customary units, which differ from Imperial in many areas. Gallon is one of the most obvious. By not metricating, the USA basically has a can of unmeasurable worms. HiLo48 (talk) 01:25, 15 August 2010 (UTC)[reply]

As it happens we have a comparison of the imperial and US customary measurement systems article. WP:WHAAOE. CS Miller (talk) 19:31, 15 August 2010 (UTC)[reply]

To be honest, I see more often the opposite bias. UK and Commonwealth posters, for some reason, are overrepresented here relative to their population, and a lot of them seem to have the idea that "international" means "not the United States". --Trovatore (talk) 10:12, 15 August 2010 (UTC)[reply]

The commonwealth is nearly 2 billion people. Sean.hoyland - talk 16:57, 15 August 2010 (UTC)[reply]

Not the English speakers. More than 60% of English-as-first-language speakers are from the United States. --Trovatore (talk) 17:18, 15 August 2010 (UTC)[reply]

Possibly true. But nothing to do with metrication. It just reinforces my point about US-centrism. HiLo48 (talk) 18:44, 15 August 2010 (UTC)[reply]

Doesn't reinforce your point even minimally. --Trovatore (talk) 18:53, 15 August 2010 (UTC)[reply]

Simple logic says that if 60% of native English speakers are from the US, there will be a US bias on English Wikipedia. But be that as it may, the bigger problem is usually one of knowledge. Most non-Americans are very aware that the US uses different spelling and measurement systems from the rest of the world. Unfortunately, too many Americans don't seem to know this. That was what I was talking about with the comment about regular. HiLo48 (talk) 19:02, 15 August 2010 (UTC)[reply]

OK, first of all the US does not use different spelling from "the rest of the world". It uses different spelling from the Commonwealth. Conflating the Commonwealth with "the rest of the world" is the bias I'm talking about, among editors who seem to think "international" means "not United States". --Trovatore (talk) 01:08, 16 August 2010 (UTC)[reply]

Ah you mean the Commonwealth is overrepresented here relative to their population of English-as-first-language speakers. I don't really see what as a first language has to do with anything nowadays. It's probably true first language-wise but that's very different from overrepresented relative to population which is what you said. I suspect that the Commonwealth is probably quite badly underrepresented in terms of English-as-second-language speakers or else I would expect to see far more Indian and Nigerian editors for example. Sean.hoyland - talk 19:07, 15 August 2010 (UTC)[reply]

Well, with second-language speakers things get much trickier. There's a huge range from "uses English very occasionally and not very well" to "operates in English on a daily basis". For the former group I would assume they would be more comfortable looking things up in the Wikipedia for their own language. Granted that these are likely less complete than English WP, and when they can't find something there they would naturally come here. --Trovatore (talk) 01:13, 16 August 2010 (UTC)[reply]

Note that for a number of commonwealth countries like India and Malaysia, the number of visitors to the English wikipedia dwarfs any other wikipedia by far (from the WMFs statistics which IMHO as I mentioned elsewhere do have flaws but it's perhaps slightly less of an issue for intra-country things). However generally speaking those who are richer etc and therefore more likely to have internet access tend to also be more comfortable using English so it doesn't really tell us that much about the rest. The statistics themselves are actually quite interesting. The not exactly commonwealth and English likely to be closer to US English, Philippines is perhaps unsurprisingly similar to the commonwealth countries I mentioned. But quite a few other countries have a relatively high proportion of English wikipedia visitors. Netherlands, Sweden, Finland, Belgium, (Israel) & Portugal for example of European. China & Indonesia for example of Asian ones. Some European ones like Norway, Romania, Denmark, Greece, Bulgaria, Lithuania, Serbia, Crotia, Slovakia, Slovenia, Estonia have more people visiting the English wikipedia then any other single one. Also true for some Asian ones like South Korea, Hong Kong (okay commonwealth in some ways), UAE, Egypt, Iran, Saudi Arabia, Kuwait. For some of these particularly Asian ones with restrictive internet access expatriates may represent a big proportion of that and of course the factors I mentioned earlier also likely play a part particularly in developing countries. Nil Einne (talk) 12:24, 16 August 2010 (UTC)[reply]

I don't think the user was trying to insult anyone. If you live in America and are used to speaking to Americans, you wouldn't ordinarily think twice about calling U.S. measurements "regular" measurements. Most Americans aren't used to speaking in forums where they may encounter people from other countries and be expected to use terms like "United States customary units." -- Mwalcoff (talk) 01:23, 18 August 2010 (UTC)[reply]

What about the US Government? --70.134.48.188 (talk) 22:48, 14 August 2010 (UTC)[reply]

My overall impression is the U.S. federal government (except the military) is a little more likely to use SI than the general public. The state governments (except the National Guard) seem to use SI to about the same degree as the general public. Various laws have been passed to try to get the federal government to use SI more, but they always seem to be greatly relaxed before they have any real effect. These impressions come from living in the U.S. For another point of view see Metrication in the United States. Jc3s5h (talk) 01:29, 15 August 2010 (UTC)[reply]

Ether

Which was named (a)ether first, the anesthetic or the "element"? --70.134.48.188 (talk) 21:01, 14 August 2010 (UTC)[reply]

The element. Aether_(disambiguation) is your friend. --Dr Dima (talk) 21:17, 14 August 2010 (UTC)[reply]

Specifically, one might compare the information in Aether (classical element)#Fifth element and Diethyl ether#History. Deor (talk) 21:20, 14 August 2010 (UTC)[reply]

The derivation of the terms might be somewhat independent. Aether just comes from the greek word for 'upper air': the philosophical use is obvious, since they were looking for something that bound everything together; the chemistry use may merely have been a reference to the fact that these compounds have comparatively low boiling points and thus are more likely to be gaseous - compare with 'ester' which refers to fatty-type substances. --Ludwigs2 23:36, 14 August 2010 (UTC)[reply]

Adrenaline

Could you inject yourself with adrenaline to give a quick burst of energy? --70.134.48.188 (talk) 23:01, 14 August 2010 (UTC)[reply]

Yes, you could. --The High Fin Sperm Whale 23:05, 14 August 2010 (UTC)[reply]

Then why don't people do that? After all, it could come in handy if you have to run for your life or fight someone hand-to-hand. --70.134.48.188 (talk) 23:07, 14 August 2010 (UTC)[reply]

because the effect would likely be short-lived, the crash after debilitating, and the risk of death unacceptably high. --Ludwigs2 23:27, 14 August 2010 (UTC)[reply]

Use of adrenaline (also known as epinephrine) can have dangerous side effects, so use for trivial reasons isn't encouraged by the medical industry. However, it does have many medical uses. — Lomn 23:28, 14 August 2010 (UTC)[reply]

Needing to run for your life or fighting hand to hand are very rare occurrences, things that never happen to the vast percentage of people in the world throughout their entire lives. Worse still, in cases where running/fighting is necessary, you probably don't have time to stand around sticking needles into yourself. Hence, carrying a shot of adrenaline around with you for that specific purpose would be kinda stupid. (Although people with certain medical conditions do actually do that - in the form of EpiPens, Anapens and Twinjects.) It's also worth mentioning that in Fight-or-flight response situations, your body produces adrenaline quite naturally - and probably in a carefully controlled optimum amount, so injecting yourself with more of the stuff is almost certainly unnecessary - and quite likely to be counter-productive. Your body does a whole bunch of other things during 'fight or flight' that make the naturally occurring adrenaline more effective. Using the stuff routinely would also be kinda stupid - it has a bunch of not-so-great side-effects and using it too often would put the body under a lot of additional stress. SteveBaker (talk) 23:36, 14 August 2010 (UTC)[reply]

It has been known for mountaineers to carry adrenaline autoinjectors with them, for the most dire of emergencies, when the physical effects of the extreme altitude on your body have sapped your strength to such a degree that you literally cannot continue and all your systems are starting to shut down - and you will certainly die where you sit if you don't open your eyes, get the hell up and carry on. --Kurt Shaped Box (talk) 02:48, 15 August 2010 (UTC)[reply]

August 15

House

I watched an episode of house (the one with the Death Row guy, 2x1 maybe?). House explains that getting the patient drunk was a treatment for the patient trying to kill himself by drinking methanol because the ethanol in liquor "bonds" with and neturalises the methanol and both just get p***ed out. I only have high school chemistry but I didn't get this part. What bonding? How can ethanol and methanol bond? 76.228.198.120 (talk) 01:24, 15 August 2010 (UTC)[reply]

See Ethanol#Antidote for methanol poisoning. The same enzyme (alcohol dehydrogenase) is responsible for breaking down both ethanol and methanol; if most of those enzyme molecules are tied up with metabolism of ethanol, then you suppress the generation of toxic products of methanol metabolism. It sounds like the phrasing from the episode was sloppy, but not totally out there. TenOfAllTrades(talk) 01:34, 15 August 2010 (UTC)[reply]

How is Hyponatremia (low sodium) diagnosed ?

How is "Hyponatremia" (low sodium) diagnosed in humans & animals ? After reading several related articles from Wikipedia, I have not been able to specifically determind how this condition is detected. Some of the articles talk about low sodium in the blood, so I am suspecting that a blood test must be taken for analysis, but I am not sure. Lindaeaton (talk) 05:28, 15 August 2010 (UTC)[reply]

I would just offer them some salt with their meal and see if they use it. -JK 92.230.64.158 (talk) 07:35, 15 August 2010 (UTC)[reply]

How exactly would that tell you if they had hyponatremia? It may be just that they don't like adding salt to whatever it is they are eating, perhaps it's already salty enough for them. I myself rarely add salt to a meal, although do use it when cooking (along with soya sauce) sparingly sometimes, but highly doubt I have hyponatremia as I eat plenty of chips and other likely salty processed foods. Of course it could even be that their doctor told them to restrict their sodium intake or perhaps they aware that they have a high sodium intake, so are trying to restrict it where possible. Nil Einne (talk) 10:16, 15 August 2010 (UTC)[reply]

You might find this link interesting. [4] Regards, --—Cyclonenim | Chat 08:11, 15 August 2010 (UTC)[reply]

The Basic metabolic panel battery of blood tests include tests for both sodium and chloride ions and can therefore diagnose both hypo- and hypernatremia. This test (also known as "CHEM-7" can be performed by a small machine - not much bigger than a laptop computer - which (as far as I can ascertain) uses photometric techniques - probably absorption spectrometry. The results are printed automatically by the machine and compared against 'normal' ranges. SteveBaker (talk) 14:34, 15 August 2010 (UTC)[reply]

is there soap in stevia?

see this

http://www.youtube.com/watch?v=-1hPIPZ-0DI&playnext=1&videos=o6oGd7iMGtU

"even distilled water gets the soap when you blend it with stevia. test it in the lab.

if you disagree, i have chemistry labs in las vegas willing to testify to this." —Preceding unsigned comment added by Tomjohnson357 (talk • contribs) 14:31, 15 August 2010 (UTC)[reply]

I would be very very skeptical of information of a claimed scientific nature found on YouTube. There are (by far) more faked videos than real ones. If this is real - you will be able to Google for it and get more details. I recommend our stevia article. SteveBaker (talk) 14:36, 15 August 2010 (UTC)[reply]

I have to agree. If there are 'chemistry labs in LV willing to testify to it' then it should be documented somewhere. And I would trust someone who provides me sources to look up rather then allege chemistry labs are willing to testify to it Nil Einne (talk) 19:31, 15 August 2010 (UTC)[reply]

this guy has made hundreds of vids on stevia his name is dan quinn —Preceding unsigned comment added by Tomjohnson357 (talk • contribs) 15:35, 15 August 2010 (UTC)[reply]

I clicked the video, but he was talking about something that "we've been dumping down our sinks for the last 80 years" - presumably not stevia. I have no idea what he's on about. Generally, there are many emulsifiers present in natural foods. Wnt (talk) 16:50, 15 August 2010 (UTC)[reply]

In fact I only see 11 videos in his Youtube profile, none of them seem to be about stevia. Dan Quinn (fighter) doesn't exactly inspire confidence you should trust him in science matters but does suggest he likes stevia so concurs that he isn't talking about stevia in the video. Nil Einne (talk) 19:42, 15 August 2010 (UTC)[reply]

In case anyone is confused, the article has now been drasticly cut down when I noticed how problematic it is and mentioned it at WP:BLP/N Nil Einne (talk) 12:02, 16 August 2010 (UTC)[reply]

Top human sprinting speed

What's the top instantaneous speed ever achieved in a track and field event? I'm thinking, of course, of Usain Bolt's latest world record. --Belchman (talk) 15:00, 15 August 2010 (UTC)[reply]

The first reference in our 100 meters article gives 10m split times for several races. In a 2008 race, Bolt ran 10m in 0.82 seconds which is 12.2m/s or 27.3 mph. CS Miller (talk) 16:37, 15 August 2010 (UTC)[reply]

Thanks, but that split is not from his current world record (set in 2009, in Berlin). --Belchman (talk) 18:34, 15 August 2010 (UTC)[reply]

The official IAAF split times [5] from a quick search for 'usain bolt split'. As I expected, there's no real difference, he achieved 0.81 or 12.35m/s. The big gain was because he didn't celebrate at the end as he somewhat controversial did in Beijing. He may have achieved a nominally higher split in the 200m race of perhaps the 100m relay of course. And the actual highest instantenous speed would have been higher then that, you could try some sort of frame by frame video analysis, trying to determine the speed between frames but at that level you run into complicating things like how you decide distance travelled and how accurate the time between frames is. Nil Einne (talk) 19:08, 15 August 2010 (UTC)[reply]

Thank you. --Belchman (talk) 21:08, 15 August 2010 (UTC)[reply]

As an addendum, I found [6] in the comments to the earlier discussed ref which gives a slightly lower split time of 0.805. Nil Einne (talk) 15:01, 16 August 2010 (UTC)[reply]

Let's look at world record times over various standard distances:

50 meters 5.56 seconds (8.99 meters/sec),
60 meters 6.39 seconds (9.39 meters/sec),
91.44 meters 9.09 seconds (10.06 meters/sec) -- 100 yard dash,
100 meters 9.58 seconds (10.44 meters/sec),
150 meters 14.35 seconds (10.45 meters/sec),
200 meters 19.19 seconds (10.45 meters/sec),
300 meters 30.85 seconds (9.72 meters/sec),
400 meters 43.18 seconds (9.26 meters/sec).

Since the average speed over 100, 150 and 200 meters are very nearly the same - but over 50, 60, 91, 300 and 400 meters, they are significantly slower, we can clearly see that the distance required to accelerate to top speed must be more than 60 to 90 meters but less than 100 meters - and stamina issues don't seem to kick in until distances over 200 meters but less than 300 meters. That says that the average speeds for the 100, 150 and 200 meter events must be pretty close to the peak speed that anyone can run - and the acceleration time is pretty negligable. So my best guess would be around 10.45 meters per second.

SteveBaker (talk) 02:04, 16 August 2010 (UTC)[reply]

Wait a sec, maybe you meant something different, but do these numbers really show that top speed is reached above 60 to 90 meters? They do show that top average speeds are achieved at distances between 100 and 200 m, but all these averages include the slow first meters. At what point do the fastest sprinters actually reach top speed? ---Sluzzelin talk 02:24, 16 August 2010 (UTC)[reply]

But that's the point. If they reached their peak speed at (say) 150 meters - then you'd expect faster average times over 150 meters than over 100 meters - especially since the effects of the acceleration time are less important over longer distances...but you don't see that. These runners can cover 100m, 150m and 200m at almost the exact same average speed. It's weird...but it's data. SteveBaker (talk) 02:29, 16 August 2010 (UTC)[reply]

It's not all that weird, because there are two competing things going on here. Yes, in a longer sprint, you can run a higher proportion of it at peak speed than in a shorter one. But the peak speed will not be as high, because you have to save more strength for the longer run. --Trovatore (talk) 02:46, 16 August 2010 (UTC)[reply]

The 100m and 200m averages happen to be very close. The 150m average would probably be higher if it was a regular event but it's an extremely rare distance and not run in championships. Usain Bolt's record [7] was not in good conditions (though it helped there was no curve) and he said "I'm not in the best shape and I still have a lot of work to do but I am getting there." Before his run there was a poor record from 1983. If there was a "10m with flying start" event where acceleration time didn't matter then I guess the peak speed would be slightly higher, because in normal races they use a lot of energy in the initial acceleration at low speed. PrimeHunter (talk) 13:40, 16 August 2010 (UTC)[reply]

It occurs to me that we're being asked about any track and field event. Is it possible that (for example) long-jumpers reach faster peak speeds? SteveBaker (talk) 02:29, 16 August 2010 (UTC)[reply]

Or pole vaulters, on their way down? Jørgen (talk) 10:35, 16 August 2010 (UTC)[reply]

Well, a spherical pole vaulter falling under the influence of a homogeneous 1g gravity field in a vacuum through the distance of the world record height of 6.15m would reach a speed of 10.98m, slightly higher than the above estimates. But pole vaulters are not spherical, or jump in a vacuum. And, more to the point, they don't really lift their center of gravity over the bar, and they don't fall back all the way to the ground (there is at least 1m of mat). So terminal speed comes out at a bit less than 10m/sec. --Stephan Schulz (talk) 12:26, 16 August 2010 (UTC)[reply]

In any case, haven't we established that the maximum instaneous speed is probably closer to 12m/s? The split times may not be perfect hence why I'm quoting a lower figure but they can't be that far off. The problem with SB's analysis is he's looking at the average speed only yet as he acknowledged you need to reach the peak speed first. We see this in the split times of course. As Trovatore has semi pointed out, you can't maintain such a peak for ever, although I don't know for sure I'd say that the peak at slightly higher distances is lower. It may be the same, or even higher and either the person takes long to reach it or they start to taper off near the end. However as I said earlier, I doubt the peak is going to be that different from what we've already got and given the problems trying to determine instaneous speeds at high accuracy it's largely a moot point anyway IMHO. Nil Einne (talk) 13:07, 16 August 2010 (UTC)[reply]

I agree. The trouble with times over shorter and shorter distances is that the fuzzy issue of which part of the body you treat as the measurement point starts to dominate the numbers. If the runner had (let's say) his nose furthest forward at the start of the 10m split time - and an arm at the forward extent of it's swing at the end of the split distance - then the runner's center of gravity may only have moved 9.5 meters rather than 10. That's what makes me skeptical that the 12 meters per second 'burst' is really valid. Plus the fact, what measurement is our OP really asking about - nose to nose, furthest-forward-part to furthest-forward-part? The results will surely be dramatically different in those two cases - and we can think of many other different definitions for "distance travelled". SteveBaker (talk) 23:03, 16 August 2010 (UTC)[reply]

Steve, look again (or for the first time, if you haven't) at the PDF linked above (it's here, to save you some scrolling). It's quite clearly not a "burst" to 12 m/s. There's some high-frequency oscillation that may indeed be explained by the body-part thing, but the main part of the curve stays above 12 m/s for ~~most~~ a large fraction of the run.

Also, your hypothesis that the stamina effect kicks in only after 150m is inherently implausible. That's not how muscles work. If you lift weights, you know very well that you can use your muscles at higher intensity if you don't have to do it for as long, going down to quite short intervals, say a single bench-press repetition.

So what's going on, I conjecture, is that the stamina effect is there from the very beginning. If there were world records kept for propelling your center of mass forward 10 meters, and 20 meters, you would find that the first 10 meters of the 20-meter world record would be slower than the 10-meter world record.

But for average speed, this competes with the effect of the time it takes to accelerate, which is why the average speed goes up, flattens out around 150 m, and then goes back down again. --Trovatore (talk) 09:41, 18 August 2010 (UTC)[reply]

You can do a quick calculation from those world record speeds. Let's assume that all the acceleration occurs during the first 50 metres (I think it's slightly less than that, more like the first 30 m, but I don't have a reliable source for that). So we subtract the world record time over 50 metres from the other times, and calculate the speed over the rest of the course: that gives 12.43 m/s for the 100-metre record and 11.01 m/s for the 200-metre record. My guess (taking into account the comments below about the 50-metre time) would be that the maximum speed of a human is a little bit less than 13 m/s (29 mph). I would expect long jumpers to be any equally good measure of this maximum speed as 100-metre runners, but we don't seem to have any hard data to go on. Anyone for pointing a radar speed-gun at a long jumper during the next big athletics meeting? ;) Physchim62 (talk) 16:12, 16 August 2010 (UTC)[reply]

I believe sprinters in training film themselves with high speed cameras and use other technology to work out which bit of their race is letting them down and how. That would suggest that the information we want is known, we just have to try and find somewhere that it has been made public. --Tango (talk) 17:13, 16 August 2010 (UTC)[reply]

Is it possible that the slower speeds for 60 and 90 metres reflect the fact that these are less prestigious events and therefore don't attract the same number of attempts to create new records? --rossb (talk) 13:27, 16 August 2010 (UTC)[reply]

I think it's certain that that is the case. The 50m record hasn't been broken for more than 14 years, while the 100m record has been broken about 10 times since then and had over a quarter of a second knocked off it. People just don't race over 50m these days. --Tango (talk) 15:15, 16 August 2010 (UTC)[reply]

It's possible that there's some effect there, but it's not obvious from the records. The average speed of the world record time goes up to a maximum and then goes down, with only a single peak; this is exactly what you would expect from the hypothesis I outline above in my response to Steve. --Trovatore (talk) 09:44, 18 August 2010 (UTC)[reply]

Nasty Prickly Sucker

On my land there is a spiny prickly plant growing near some english ivy on some rocks. Unfortunately I fell down on it on thursday and am living with itchy red bumps on my hand. I was wondering if anyone could identify the plant for me and I can do some research on it.. Thanks. schyler (talk) 15:03, 15 August 2010 (UTC)[reply]

I can't identify it, but it reminds me of Datura stramonium or (vaguely) Solanum carolinense - if you don't get a real answer here, try posting this image at Talk:Solanaceae. There are still quite a few species Wikimedia Commons still needs to get pictures of, so please don't throw out this photo! Wnt (talk) 17:14, 15 August 2010 (UTC)[reply]

Are you quite sure it wasn't the ivy you were reacting to? My husband comes out in hives if he touches ivy. --TammyMoet (talk) 18:30, 15 August 2010 (UTC)[reply]

Displacement time response

If we displace an amount of gas trapped in a medium, will it take a time estimated by the speed of sound in this medium in order to sense this displacement at a distant point? If yes, does this rule apply to liquids and solids (for example displacing a steel bar of length of about 10 km and sense the first response of this displacement at the other end)?--Email4mobile (talk) 16:26, 15 August 2010 (UTC)[reply]

Yes, that's about accurate. It is especially accurate for the steel-bar case, and is pretty accurate for an incompressible fluid (liquid). In a gas (or liquid), the actual propagation time is confounded by convection and bulk movement of particles, which are a fairly nonlinear process. Often, multiple speeds are defined for a fluid - such as p-wave and s-wave speeds for elastic fluids; and in other fluids, empirical descriptions of travel-time speeds can be defined. Generally speaking, bulk fluid motion is sub-sonic, so information propagating as an acoustic pressure wave will usually arrive before any other method of information propagation, including shear-waves, rayleigh waves, or convective or bulk fluid movement. An important exception is a detonation or supersonic shock front, where bulk movement of air particles is forced to occur at a speed greater than their resting acoustic sound-speed. Transsonic and supersonic fluids behave very strangely, for exactly this reason - their "normal" method for particle interactions is too slow to account for the actual changes in mass, energy, and momentum distribution. Nimur (talk) 18:44, 15 August 2010 (UTC)[reply]

Relay race strategy

Why do you think that the "second fastest, third fastest, slowest, then fastest (anchor)" strategy is the most used in relay races? --Belchman (talk) 18:32, 15 August 2010 (UTC)[reply]

Probably nothing except psychological reasons. Fastest man last is obvious - best chance on that sprint to the finish line. second fastest first hopefully gives a little bit of a lead at the beginning, so the two slowest runners (who usually aren't particularly slow, mind you) can focus on maintaining a lead they already have rather than trying to catch up to others. --Ludwigs2 22:35, 15 August 2010 (UTC)[reply]

the first runner is the only one who has to accelerate from a standing start, so more than psychological factors come into play. Looie496 (talk) 00:47, 16 August 2010 (UTC)[reply]

But the last runner is the only one who is able to risk running out of stamina in a sprint to the finish line. SteveBaker (talk) 01:41, 16 August 2010 (UTC)[reply]

honestly, it's probably just a status thing. first and last runners are the ones people are most likely to remember, so they go to the team stars. the rest is just rationalization. The race is won by the collective time of all four racers (barring fumbled batons and such), and there's no technical reason why the order they run in should matter. --Ludwigs2 02:08, 16 August 2010 (UTC)[reply]

Yes and both of those are why second fastest first and fastest last make sense. As for the other two, third fastest second may have some psychological advantage in reducing how far they may fall behind. (I thought of this earlier today before anyone had replied but didn't say anything but since everyone else is speculating why not?) Of course whether these factors actually get any consideration or it's really just tradition, status or whatever I don't know. Nil Einne (talk) 11:58, 16 August 2010 (UTC)[reply]

One factor that I have seen have an impact, particularly in 4 X 100 relays, is who runs best around the curve. Those best at doing so would get the first and third legs. HiLo48 (talk) 12:12, 16 August 2010 (UTC)[reply]

how do armless people masturbate

like this guy

http://cdn2.sbnation.com/imported_assets/521792/kylemaynard_medium.jpg

—Preceding unsigned comment added by Tomjohnson357 (talk • contribs) 19:11, 15 August 2010 (UTC)[reply]

Well, I admit I have no personal experience with this at all. It might just not be possible in some cases, depending on the degree of the paraplegia, though one should never underestimate the human ingenuity that surrounds ways of sexual self-gratification. (One could imagine, for example, that "props" — like a Dutch wife, or even just the old fashioned "hole in a pillow" method — could be employed to pretty good effect by males, even without the use of hands. For females, I imagine the use of toys is probably still possible for the dextrous.) But apparently there has been at least one book written on the subject of paraplegic sexual activity, and from the review linked to, I wouldn't be surprised if it discussed these kinds of options. --Mr.98 (talk) 19:39, 15 August 2010 (UTC)[reply]

By rubbing oneself against an inanimate object. 82.44.54.4 (talk) 19:47, 15 August 2010 (UTC)[reply]

that would hurt a lot —Preceding unsigned comment added by Tomjohnson357 (talk • contribs) 21:07, 15 August 2010 (UTC)[reply]

I don't see how. Put a pillow between your legs and rub on it. Does it hurt? If it does I suggest you seek the advice of a doctor. 82.44.54.4 (talk) 21:15, 15 August 2010 (UTC)[reply]

Let me clarify the IP's suggestion: rubbing oneself against a soft inanimate object. A soft easily washable inanimate object for men! --Tango (talk) 21:46, 15 August 2010 (UTC)[reply]

Hookups. John Riemann Soong (talk) 21:35, 15 August 2010 (UTC)[reply]

it does hurt if you are circumcised. theres no lubrication. chafing ect. do their nurses masturbate them? —Preceding unsigned comment added by Tomjohnson357 (talk • contribs) 22:27, 15 August 2010 (UTC)[reply]

So then, um, one uses lube if "no lube is a problem". I think your question has been answered here. DMacks (talk) 22:44, 15 August 2010 (UTC)[reply]

While I appreciate circumcision can make things more difficult our article specifically mentions rubbing against an inanimate object as a common male masturbation technique (I've even read debates about whether it's harmful), I'm pretty sure that some circumcised males must do it. If it's not possible for you, either you're not doing it right or there's a specific health issue that we can't help you with. Of course outside of masturbation Non-penetrative sex#Frottage is also a fairly common sexual practice and depending on precisely what's being done may share some similarities. In any case, using lubrication is always advisable if there is any pain or other such problems during masturbation and is often useful particularly for circumcised males. BTW, the first result for 'hands free masturbation' is [8] although the picture doesn't show what's described in the text (shouldn't need to say it isn't work safe). Incidentally I also came across [9] which I think is a serious site, for circumcised males. Nil Einne (talk) 23:15, 15 August 2010 (UTC)[reply]

do their nurses masturbate them? —Preceding unsigned comment added by Tomjohnson357 (talk • contribs) 02:25, 16 August 2010 (UTC)[reply]

We are being trolled by Tomjohnson357. This is not a scientific question and so is not appropriate for this Reference Desk. Dolphin (t) 02:45, 16 August 2010 (UTC)[reply]

I think that such questions are perfectly in order. Had they been on some similar (non-sexual) theme—as to how native peoples cut their toenails, for example—there would have been no cause to object. It is wowsers attempting to censor WP.

The more relevant question is how do quadruple amputees cut their toenails? -- 111.84.151.46 (talk)

I do remember reading (and that means this is a reference to a reputable third party and therefore within the ambit of WP) that during the 1950s, a Russian youth, rendered armless through an industrial accident on a collective farm, bought a cow milking machine for the purpose of masturbation. He managed to attach one of the rubber teats to his penis and turn the machine on with his teeth. He had a wonderful first orgasm and then a second. After that, his penis became sore and he tried to switch the machine off and remove the teat, but with no success. He had a third orgasm and by then was becoming desperate. Somehow, he got to his phone and rang the factory that produced the milking machines and told them he was having trouble turning it off, without, of course, telling them what he was using it for. Oh, said the girl on the switchboard “That’s OK, it will stop automatically when the bucket is full...” Myles325a (talk) 03:20, 16 August 2010 (UTC)[reply]

Will Myles325a be providing the reference to the reputable third party source? No? I thought not. Dolphin (t) 03:33, 16 August 2010 (UTC)[reply]

That sounds like the kind of urban legend where a true story of someone being an idiot gets embellished with the addition of an ironic punchline and some extra details to try and make it sound more believable. The idea that someone would use a milking machine to masturbate is highly plausible, in fact, I'd be very surprised if it has never happened (although, chances are they weren't armless and didn't buy it, they probably worked on a dairy farm) but the "it will stop when the bucket is full" bit was probably just added on for a joke (cow milking machines don't have buckets, for a start, they have massive tanks, you only use a bucket for hand milking). What was this reputable source? Was it either someone saying they did it themselves or a doctor saying they treated somebody that did it? If it wasn't one of those two, it isn't reputable. --Tango (talk) 04:09, 16 August 2010 (UTC)[reply]

You're mostly correct. The same milking machines that feed the bulk tanks can have a bucket put on them for cows that have been treated with any medicines that shouldn't be put into the bulk milk. Dismas|^(talk) 09:44, 16 August 2010 (UTC)[reply]

I recall reading pretty much exactly that story in the "True Stories!" section of an FHM magazine about ten years ago. That, of course, is about the most cast iron guarantee possible that it's not true at all. ~

mazca ^talk 09:37, 16 August 2010 (UTC)[reply]

While it's not an RS for the milking machine story, I can offer Br. Med. J.: 1942, 1960, doi:10.1136/bmj.1.5190.1942 {{citation}}: Missing or empty |title= (help) as a source for a similar line of action: this New Scientist article (for 1985, so 25 years after the original publication), suggests that men are somehow destined to repeat the errors of their fathers (or uncles, or whatever!) Physchim62 (talk) 15:50, 16 August 2010 (UTC)[reply]

Humor aside, someone ought to use the older reference there, and others findable by search, to start an article penrig, for one of the more peculiar units of measure in the world. Wnt (talk) 16:20, 16 August 2010 (UTC)[reply]

Done Physchim62 (talk) 17:27, 16 August 2010 (UTC)[reply]

Also just in case anyone is wondering about the other important issue raised here regarding how native peoples cut their toenails, my extensive studies have shown that the hill tribe people of Laos favour an odd looking device fashioned from what appears to be a metallic material. It features some kind of symbolic language. It's difficult to make out but it appears to say something like "nipping Chuangxing Nail Clippers Made in China 100mg". Sean.hoyland - talk 10:00, 16 August 2010 (UTC)[reply]

Where legal, it seems far more likely a sex worker would be hired instead. BTW, in terms of the story, beyond the bucket issue there's also another what seems to be obvious flaw in the story. Cows don't have an unlimited amount of milk. If your cow is out of milk continously milking it until the bucket is full is not going to do anything but injure the cow. In modern times of course, a machine without some sort of safety off is going to fall foul of OSH regulations in most developed countries. Nil Einne (talk) 11:54, 16 August 2010 (UTC)[reply]

most armless people cant afford sex workers. and its not legal most places either. most do have full or part time nurses though. is it legal for them to masturbate the man? —Preceding unsigned comment added by Tomjohnson357 (talk • contribs) 17:48, 16 August 2010 (UTC)[reply]

If they are armless and have financial difficulties I would suspect they have bigger things to worry about then masturbation (no pun intended) Nil Einne (talk) 19:46, 16 August 2010 (UTC)[reply]

i cant imagine whats worse than lying in bed every night with a painful erection. —Preceding unsigned comment added by Tomjohnson357 (talk • contribs) 19:50, 16 August 2010 (UTC)[reply]

If you have painful erections every night when you don't masturbate, you should see a doctor. As for the more general point you clearly have never lived a life (or even thought of one) in financial difficulty if you genuinely think masturbation is that important. (I haven't either but it's something you can contemplate.) Not having enough food to eat, not knowing if you will have a home tomorrow, not being sure if you could afford the things like electricity that you need for the home even if you have one, not being sure if you can afford any home help to do any basic things you can't manage like tidy up your home (you mentioned a nurse, I'm not really sure what this 'nurse' is for but they're definitely not going to be cheap), not being sure if you can afford a doctor for when you have medicial issues (which I would guess are probably more common for an armless person), are plenty of things which an armless person in financial difficulties is likely to be more concerned about then masturbation Nil Einne (talk) 16:58, 17 August 2010 (UTC)[reply]

Freshwater fiddler crab

The fiddler crab article reads like a handbook but avoids sourcing its statements. I would like to purchase a couple of fiddler crabs for my 29G freshwater tank and have 4 concerns: the article states that there is really no such thing as a freshwater fiddler crab and that they should not be kept in freshwater for more than a day or so -- is this accurate information? Secondly, must I have rocks branches in the water that allow the crab to break the surface, or can they live totally underwater? Thirdly, if I get a male and a female, how likely will they mate? And fourthly, should I worry that they will catch/kill my fish? I have some neon tetras, platys and mollies -- I had crayfish as a kid and I fed them live minnows. Will the crabs do the same? DRosenbach ^{(Talk | Contribs)} 19:15, 15 August 2010 (UTC)[reply]

Fiddler crabs aren't really predators, but you can still end up with something like this: [10] Unfortunately each aquarium, its size and layout and food and fish, is a different experiment, far removed from normal ecology - no scientific publication is likely tell you whether each of your fish are safe. I see many websites stating that fiddler crabs don't thrive in fresh water. To contradict them, could someone examine fulltext of [11], [12]? (regarding Uca minax, Uca spinicarpa) Based on the long but not infinite time that aquarium specimens can spend in freshwater, and the absence of fiddler crabs far from the sea, I suppose there must be some sticking point - can they breed in fresh water? I wonder if you could take a few different freshwater species, hybridize them to improve genetic variation, and passage them for a few generations in increasingly fresh water until you have a new crabby counterpart to Caulerpa taxifolia to unleash on the river ecosystem?

Time

Please explain the phrase "Abyss of Time"

Thank you

User: Center 33 —Preceding unsigned comment added by Center39 (talk • contribs) 20:05, 15 August 2010 (UTC)[reply]

This is primarily a metaphorical way of displaying the seemingly indefinite and eluding concept of time. Tyrol5 [Talk] 20:07, 15 August 2010 (UTC)[reply]

And in some cases it may be an allusion to Prospero's phrase "the dark backward and abysm of time" in Act I, scene 2, of The Tempest. Deor (talk) 20:52, 15 August 2010 (UTC)[reply]

Quoting, "The Abyss of Time is a massive underground labyrinth that appeared in the playable epilogue in Persona 3: FES, titled The Answer. Originally a state of hibernation, it became 'active' when it was attracted by the grief and sorrow of SEES, and spread it's influence there, rooting down below the dorm.". The moral is that questions like this can't be answered without knowing the context. Looie496 (talk) 20:54, 15 August 2010 (UTC)[reply]

Dinosaurs eating one another

Is there a similar order of animals that eat one another as a primary part of their diet? Obviously dinosaurs dominating the world was a factor in such carnivory, but I just wonder. Thanks. 67.243.7.245 (talk) 20:37, 15 August 2010 (UTC)[reply]

Uh, mammals? Uh, birds? Uh, fish? Uh, insects? It's harder to find an order of animals that doesn't. Looie496 (talk) 20:56, 15 August 2010 (UTC)[reply]

Mammalia and insecta are both classes and fish is a confusing collection of classes and phyla. Birds and dinosaurs are both complicated due to the differences between Linnaean taxonomy and phylogenetic taxonomy (in short, birds evolved from dinosaurs but appear completely different, so should birds be considered a type of dinosaur? The Linnaean approach says no, the phylogenetic approach says yes.) but if we use the Linnaean conventional taxa aves is a class and dinosauria a superorder. So, I think the best interpretation of the OP's question is to find a superorder or smaller in which members eat each other as a primary part of their diet. One example I can think of is polar bears eating seals - they are both in the order carnivora (I'm sure there are other examples from that order too, but this is the first I thought of). --Tango (talk) 04:30, 16 August 2010 (UTC)[reply]

(EC) Sorry I'm confused what the question is. There are plenty of modern day carnivores if that's what you're asking. Many species of Felidae for example. Note that dinosaurs were a diverse bunch of animals and the dinosaurs generally ate rather different dinosaurs. The fact that dinosaurs were eating dinosaurs isn't really that different from the fact many mammalian carnivores primarily eat other mammals Nil Einne (talk) 20:58, 15 August 2010 (UTC)[reply]

The relevant article might be Cannibalism in animals. It's rather common in some species. EverGreg (talk) 07:48, 16 August 2010 (UTC)[reply]

All dinosaurs are not members of the same species; so it is not strictly accurate to call a Tyrannosaurus a cannibal if it eats other species of dinosaur like hadrosaurs. Nimur (talk) 08:33, 16 August 2010 (UTC)[reply]

Absolutely true. EverGreg (talk) 10:56, 16 August 2010 (UTC)[reply]

Weasels' primary predators are other members of the order Carnivora. APL (talk) 15:30, 16 August 2010 (UTC)[reply]

Chimpanzees are (now) known for devouring other primates... Wnt (talk) 15:36, 16 August 2010 (UTC)[reply]

And some members of the subtribe hominina eat other primates as well.... CS Miller (talk) 20:09, 16 August 2010 (UTC)[reply]

Is there a specific name for this concept?

An animal that generally avoids predation by being too big for anything that's fast enough to catch it to take without great difficulty - and also too fast for anything that's big enough to take it to catch it without great difficulty. This came up when discussing gulls with someone this afternoon - as some of the larger larids are a bit like this. --Kurt Shaped Box (talk) 22:18, 15 August 2010 (UTC)[reply]

No, but there is a name for the opposite category: dinner. Looie496 (talk) 02:15, 16 August 2010 (UTC)[reply]

The usual term is "having no natural enemies" or "natural predators". According to wikipedia, the adult elephant is one example, though animals may prey on young or weak individuals. EverGreg (talk) 07:55, 16 August 2010 (UTC)[reply]

Under Kurt Shaped Box's specification, would not this require there to be a predator larger but slower than an elephant? (87.81 posting from . . .) 87.82.229.195 (talk) 11:19, 16 August 2010 (UTC)[reply]

Blue whale is larger and at least on land it is slower than elephants and it is a predator.--Gr8xoz (talk) 14:41, 16 August 2010 (UTC)[reply]

This is a complex topic, and such a simple rule wouldn't generally be accurate. Consider camouflage, mimicry, venoms and poisonous compounds, general unpalatability, armor, spines, ink sacs, and just plain dexterity - among many others, no doubt. Also remember that small predators can take down a larger prey (lions devouring a full-grown elephant, as shown beautifully in a Planet Earth (TV series) episode [13]. At the extreme, consider MRSA taking down a human... Wnt (talk) 15:32, 16 August 2010 (UTC)[reply]

Perhaps there is something in Antipredator defenses in birds and mammals By Timothy M. Caro Sean.hoyland - talk 15:41, 16 August 2010 (UTC)[reply]

Workings of a rolling mill

My 1988 World Book Encyclopedia says that a hot-rolling mill can take a piece of steel 5 inches thick by 8 feet long and produce a sheet 1/16 inch thick and 1,400 feet long; the width of the piece isn't mentioned. In other words, the final thickness is 1/80 of the original thickness, but the final length is 175 times the original. I can't understand: how could this be done without violating the conservation of mass? Would the final width be less than half of the original? Please note (1) the diagrams on the facing page are side-on, not showing width, and (2) I've read the section to which rolling mill is a redirect, but I can't find an answer. 71.79.87.249 (talk) 23:54, 15 August 2010 (UTC)[reply]

I think when they say 8 feet long, they actually mean 8 feet wide, the 8 foot width stays the same, and the length "1,400" is meaningless since they don't give you the starting length. A rolling mill is a continuous process. I don't think they work with 8 foot batches (although the article does imply that at least historically they used to, but I'm pretty sure they don't anymore). This is just a guess though. Ariel. (talk) 00:21, 16 August 2010 (UTC)[reply]

Actually I think they still do. See this explanation of a continuous mill that uses billets of metal. Rmhermen (talk) 14:47, 16 August 2010 (UTC)[reply]

This sounds much like wire drawing, where a short thick rod becomes a long thin wire. As the metal goes from one set of rollers to the next, it becomes thinner and moves faster. No "extra mass" is created. The width must be constrained to be no wider than the rollers at each stage. A rectangular billet which was not too wide could become a thinner and wider and longer sheet of about the same volume and of exactly the same mass (neglecting any Einsteinian mass/energy equivalence, not likely to be a significant effect in a rolling mill). Edison (talk) 23:25, 17 August 2010 (UTC)[reply]

August 16

Deutz gadget.

I have a gadget made by Deutz Germany in 1914 with a serial number GJ140740C. Can anyone please help me what it is and what is it used for 212.49.89.76 (talk) 11:33, 16 August 2010 (UTC)Kamen.[reply]

Deutz is a huge name in Germany. I'm sure they made thousands of different types of gadget. The serial number on your Deutz gadget is of no help in identifying it. I suggest you post a photograph of it here. Or at least a comprehensive description of its size and shape. That way the Science Reference Desk might be able to help. Dolphin (t) 11:39, 16 August 2010 (UTC)[reply]

If the data plate also has a model number, then we might be able to track down what the device is. However, as Dolphin said, a photograph would be better; you can upload it to wikipedia by following the Upload file link in the left-hand toolbar, but you need to be an autoconfirmed user to this; i.e. have an account for more than 4 days and make more than 10 edits. CS Miller (talk) 19:53, 16 August 2010 (UTC)[reply]

planet

Why planets revolve around the sun what force is responsible for elliptical path —Preceding unsigned comment added by 117.96.132.254 (talk) 13:36, 16 August 2010 (UTC)[reply]

You may be interested in our article on the formation and evolution of the Solar System. In a nutshell, angular momentum is conserved, and the initial momentum of the primordial molecular cloud is preserved today in part via the orbits of the planets. — Lomn 13:46, 16 August 2010 (UTC)[reply]

Why all planets revolve around the sun gravitational force does not force to follow elliptic path than what is responsible —Preceding unsigned comment added by 117.96.132.254 (talk) 13:54, 16 August 2010 (UTC)[reply]

The Sun is not the only gravitational force on the planets. They interact with one another as well. -- kainaw ™ 14:03, 16 August 2010 (UTC)[reply]

Yes but the gravitational effect of other planets is relatively minor, and tends if anything to make the orbits not exactly elliptical. The short answer is that if a planet starts off moving in a certain range of speeds and directions, gravity will make it follow an elliptical orbit around the Sun. 20th Century physics (quantum theory) has modified the detail, but broadly the elliptical paths are almost exactly what Newton's law of gravity would predict. --rossb (talk) 14:14, 16 August 2010 (UTC)[reply]

General relativity is a far more significant correction that quantum theory for celestial mechanics. It's still fairly small for any planet other than Mercury, though. --Tango (talk) 14:28, 16 August 2010 (UTC)[reply]

OOPS - of course I meant to say general relativity! --rossb (talk) 17:05, 16 August 2010 (UTC)[reply]

I assumed the questioner was asking why the orbits are not exactly elliptical with the phrase "does not force to follow elliptical path". If the questioner would care to ask a question with a complete sentence, we can surely provide a good answer. -- kainaw ™ 14:34, 16 August 2010 (UTC)[reply]

Articles like Kepler's laws of planetary motion, Kepler orbit, and just orbit may be helpful, though bits of insight are mixed in with a lot of complex mathematics. The discovery that orbits weren't circular shortly after 1600 did a lot to create (or spur the discovery of) such complex math. But the principle is really quite simple: the motion of an object (ignoring friction) in one dimension is completely unrelated to its motion in another. As shown beautifully in a Mythbusters episode, a bullet fired drops at the same rate as a bullet that is simply dropped. For a planet, what this means is that if it could fall straight through the sun, come out to the other side, and repeat, that straight-line pendulum-like motion is exactly the same as if the planet revolves in a perfect circle, from the point of view of that one dimension. Likewise the orbit of a planet will be an ellipse when it falls back and forth a greater distance in one direction than in another. (You may ask why it can't fall back and forth in the third dimension for some 3D orbit - answer is, if it does so, it works out that this is a 2D orbit in some other plane) This isn't perfectly true for a real planet however due to other factors - due to the precession as discovered by Newton and then the distortion calculated by Einstein in the two-body problem in general relativity. Wnt (talk) 15:21, 16 August 2010 (UTC)[reply]

Here is the answer that I think the OP is looking for: Isaac Newton proved mathematically that if the force of gravity drops off in proportion to the square of distance from an object, then orbits will be ellipses. So the answer is indeed gravity, although it takes a lot of work to see why that is the answer. Looie496 (talk) 19:51, 16 August 2010 (UTC)[reply]

PLACEBO

WHAT IS PLACEBO? —Preceding unsigned comment added by 124.253.228.118 (talk) 13:58, 16 August 2010 (UTC)[reply]

See placebo. -- kainaw ™ 14:00, 16 August 2010 (UTC)[reply]

Can you make a "fire hose" that shoots solid ice?

I was looking at the phase diagram of water recently, and was quite surprised to notice a "horn" where water at just a certain pressure around 2 x 10⁸ Pa is liquid all the way down to 250 K. What strikes me about this is that water can't be heated with perfect uniformity, but its pressure can be released at the same rate throughout the liquid. This would seem to suggest to me that if you had a fire hose with a region of high pressure that gradually reduced, the water could be turned into a solid cylinder of ice as it came out! (Presumably friction applied to the side of the ice somewhere down the line would help maintain the high pressure at the base) Besides being just an odd-looking curiosity, I think such a device might be helpful in outer space, where liquid water is prone to evaporate, but well-cooled ice is a structural element practically as strong as steel. But could it work? Wnt (talk) 16:34, 16 August 2010 (UTC)[reply]

The ice would sublime when exposed to sunlight though. Not a good idea to have a space station made of the same material as a comet. John Riemann Soong (talk) 16:43, 16 August 2010 (UTC)[reply]

So you spray it with a visually reflective, IR-black paint as it emerges from the hose. I was just looking at black body - the Earth would be 250 K on its own, and halving its albedo from .3 to .15 would reduce that by 1/4th root of 2 = 16% to 210 K. I'd have to look at the Sun's fraction of IR output to see how low it possibly can go, but this seems good enough for sci-fi. ;) Wnt (talk) 17:19, 16 August 2010 (UTC)[reply]

Whether the radiation is IR or not makes no difference, all light will heat an object that absorbs it. IR is just the frequency range of light emitted by objects at every-day temperatures (basically, anything colder than red-hot (by definition) and warmer than liquid helium (roughly)) Ice, formed in the correct way, is already highly reflective (consider snow), so I doubt you'll be able to spray it anything better, just make sure the ice is white ice not clear ice (although, clear ice wouldn't be a problem as long as it isn't very thick, since the light would just go straight through it). You won't be able to make it a perfect reflector, though, so it will still sublime at some rate. I don't think you need high pressure, though, can't you just have the water in most of the hose at room temperature and then have the final, straight bit of hose immersed in liquid nitrogen? --Tango (talk) 17:25, 16 August 2010 (UTC)[reply]

I was actually thinking of a hose without a nozzle, perfectly smooth cylinder, using friction only on the fully cooled part of the ice to hold back the remainder. Wnt (talk) 17:52, 16 August 2010 (UTC)[reply]

So was I. If there were a nozzle, the ice would block it. --Tango (talk) 01:43, 17 August 2010 (UTC)[reply]

Hmmm... the more I think about this, the more I'm confused. Somehow I imagined that the crucial pressure gradient near the freezing point would be created by the acceleration of the water/ice as it spewed out, and the acceleration would be created by the pressure gradient. But I'm not sure whether such a description really makes any sense. Wnt (talk) 12:29, 17 August 2010 (UTC)[reply]

I am not convinced that the water will come out as a cylinder. Rarefaction waves and solidification fronts near the nozzle may turn it into a shrapnel of ice crystals and frozen droplets; you will need to put a lot of thought and effort into the nozzle design. Having the pressure drop gradually but preventing the water from freezing in the nozzle at the same time is an interesting challenge. This may turn out to be useful for future missions to the ice-rich bodies in the Solar System (Galilean satellites for example), although personally I have doubts. The thing is, on the ice-rich bodies you don't care about evaporation losses during the manufacturing process too much; and in the Earth orbit or on Mars the water is too expensive to spray it around, pressurized or not. Still, an interesting idea. Did you search the literature to see if people have tried this on Earth? May be more useful here than in space. After all, people have known for a very long time that pressure prevents water from freezing. --Dr Dima (talk) 17:26, 16 August 2010 (UTC)[reply]

It's not really my field, and it's hard for me to think of unique search terms (ice, pressure... no). I was envisioning a snazzy way to make a very large telescope quickly from a central pool of resources. ;) Wnt (talk) 17:52, 16 August 2010 (UTC)[reply]

How would lots of ice help you make a telescope? You need enormous mirrors and/or lenses for that, and while you could make a lens out of ice, I suppose, your method wouldn't do that (the precision required for a lens is very high). --Tango (talk) 01:43, 17 August 2010 (UTC)[reply]

Well, the mirror was pictured to be a very thin sheet of metal, suspended by "billions and billions" of nanotech tendons (I'm picturing something like two telescoped SWNTs and a basic control circuit - but it must be rigid enough to push as well as pull on the membrane, so a cable of such may be required). Some hard scaffold is needed for them to attach to, and to mediate reorientation of the telescope, which is what the ice was for. Wnt (talk) 12:29, 17 August 2010 (UTC)[reply]

Isn't this essentially what a snow cannon is doing? Admittedly, they intentionally form a fine mist, and also rely on evaporative cooling, but they do essentially convert water into ice via spraying it out of a nozzle at high pressure. --Stephan Schulz (talk) 15:44, 17 August 2010 (UTC)[reply]

As you can tell by the intolerable noise, snow guns are just giant fans with a bit of water added in. While perhaps they could add a bit more if they wanted chunks of ice rather than "snow", the limitation applies that you can't cool the liquid uniformly ... unless you mix it with a larger amount of uniformly cold material, here air. A snow gun that's all water and no air would simply pour out water. Wnt (talk) 03:59, 18 August 2010 (UTC)[reply]

EKG Analysis- practice Test

Last year I accessed a link for Wikepedia (EKG Analysis), a 129 quesiton practice test, multiple choiuce, true/false and fillins. An excellent study tool. Is to still available? —Preceding unsigned comment added by 168.28.203.185 (talk) 16:56, 16 August 2010 (UTC)[reply]

This sounds like the sort of thing Wikiversity or Wikibooks might handle. There's only a tiny page at Wikiversity, but maybe a related page is what you're looking for. Check your browser history for wikiversity, or see if any link at [14] looks familiar or is still colored from the last time you visited. Wnt (talk) 17:56, 16 August 2010 (UTC)[reply]

pH buffer of 1 or 1.5 (out of household/edible/supermarket ingredients)

I need a moderately acidic solution ... this solution would be mildly corrosive, right? I want a low pH but without so much H+ that acid-catalyzed side reactions become significantly active (hydrolysis, Fischer-style condensation). My goal is to supply a reaction that would steadily consume H+ (a lot of it!), but I want to avoid side reactions. It doesn't have to be a very precise buffer, as you can see. Btw, what's the pH of pure glacial acetic acid? Google seems to tell me 2.4, but this is surprising to me because my orgo prof told me that glacial acetic acid will prune your fingers almost immediately but vinegar takes a while to this. (I mean I spill vinegar on myself all the time while preparing meats.) John Riemann Soong (talk) 17:15, 16 August 2010 (UTC) If true edibility is desired, lime (fruit) juice (2.0) is the sourest I've ever heard of. For lower pH (truly strong acid) then a more chemical approach is needed - hydrochloric acid is not intrinsically poisonous, apart from its acidity ... I suppose there must be a food grade somewhere, as it's used extensively to adjust pH of pharmaceuticals. You should confirm your original question: pH 1 means a lot of H+ all at once by definition. If you want to supply a lot of H+ slowly, glacial acetic acid will provide an H+ from (almost) every molecule, without ever going to such low pH. Wnt (talk) 18:04, 16 August 2010 (UTC) Well I think it's a reaction that consumes H+ abundantly (it's a redox reaction), so unless I want a reaction that takes a million years to complete, so I need a fair bit of H+. But I don't want to catalyse something unwanted. Are there any organic acids whose conjugate bases are stabilised (or precipitated) by some other complex in solution? John Riemann Soong (talk) 18:15, 16 August 2010 (UTC) I think you'll have better luck searching for prior art for your specific reaction. Anything that can possibly be done by someone who's asked what the pH of acetic acid is, is already published somewhere in great detail. If you don't have good access to normal literature sources, try Patent Lens. Wnt (talk) 18:35, 16 August 2010 (UTC) I want to stabilise the intermediate Chromium(VI) peroxide before it decomposes, which I am told is fairly short-lived. I plan on using a dry-ice/acetone bath. Initially, the production of Chromium(VI) peroxide is more rapid than its decomposition. Both processes are acid-consuming processes, so I want there to be enough acid for the first reaction but insufficiently enough for the second one. Apparently decomposition of Cr(VI) peroxide requires more H+ than production ... (details in article) Btw, I expected the pH of glacial acetic acid to be quite different from an aqueous solution because the H+ species is not the same. One is solvated hydronium, and the other H+ species probably has a higher acidity function, what with the poor-stabilisation of protonated acetic acid and all. John Riemann Soong (talk) 20:35, 16 August 2010 (UTC)

I see what you mean about glacial acetic and the Hammett acidity function (e.g. [15]), if the solution is nearly free of water. But such a system won't run out of H+ after the first reaction and before the second. I don't know if you can do that effectively. Most of the information I'm seeing on a quick search has to do with stabilizing Cr0₅ in adducts as described in Chromium(VI) peroxide and Chromium, but I could be missing a lot here. Wnt (talk) 00:43, 17 August 2010 (UTC)[reply]

Gene Therapy/Hormones

Is it possible for gene therapy to increase or decrease the amount of certain hormones/chemicals in the body? —Preceding unsigned comment added by 71.156.3.118 (talk) 17:45, 16 August 2010 (UTC)[reply]

Certainly possible - difficulty depends on the hormone/chemical. See e.g. [16] about phenylketonuria, a disease that begs for an outside source of phenylalanine hydroxylase to reduce the amount of phenylalanine (and phenylpyruvate...) by converting it to tyrosine. Wnt (talk) 18:08, 16 August 2010 (UTC)[reply]

Our article on gene therapy doesn't mention hormones at the moment. Quite a few papers have been published discussing using gene therapy to introduce growth hormone into rats and mice, but I can't find anything about it being used in humans yet. Smartse (talk) 11:45, 17 August 2010 (UTC)[reply]

Take a look at the "Repoxygen" article. Also the "gene doping" article. —Preceding unsigned comment added by 76.169.33.234 (talk) 02:52, 18 August 2010 (UTC)[reply]

EPO

is epo Erythropoietin available as a pill or only a injection? —Preceding unsigned comment added by Tomjohnson357 (talk • contribs) 18:03, 16 August 2010 (UTC)[reply]

Erythropoietin is a glycoprotein hormone so it's difficult to imagine the point of a pill other then perhaps if you need more protein in your diet but it's going to be a rather expensive protein source. Nil Einne (talk) 19:43, 16 August 2010 (UTC)[reply]

What he's trying to say is that if you ate it the protein would be digested, and it wouldn't be Erythropoietin anymore, but rather individual amino acids. Ariel. (talk) 19:51, 17 August 2010 (UTC)[reply]

Its injection only. Look up "Procrit" on wikipedia or another source.

People have been trying to get proteins into the bloodstream for something close to 90 years now. Every few years someone writes a hopeful review. Sooner or later they're bound to be right... Here's a patent application you might find interesting - no promises it works, and I doubt that it's safe.[17] Would be funny if the dope dealers beat the pharmaceutical companies to market after all that time... Wnt (talk) 20:09, 18 August 2010 (UTC)[reply]

August 17

HAARP Effects On Ionosphere

What are the serious repercussions when HAARP is used on the ionosphere? Is the HAARP destroying the ionosphere?174.114.236.41 (talk) 04:07, 17 August 2010 (UTC)[reply]

How could it possibly do that? It's 3.6MW of power - which is absolute peanuts compared to the energy the sun puts into the ionosphere. It does sound cool though, no? Playing with the ionosphere, it sounds very mysterious and strange. But 3.6MW is about the same as 20-40 cars running at full power. Ariel. (talk) 05:24, 17 August 2010 (UTC)[reply]

According to the article HAARP has been blamed for triggering catastrophes such as floods, droughts, hurricanes, thunderstorms, devastating earthquakes in Afghanistan and the Philippines, power outages, the downing of TWA Flight 800, Gulf War Syndrome and Chronic Fatigue Syndrome. Not to be outdone at recklessly irradiating the ionosphere, the Norway based EISCAT installation is capable of transmitting over 1 GW ERP. Wearing a Tin foil hat is a possible precaution. Cuddlyable3 (talk) 14:36, 17 August 2010 (UTC)[reply]

From the article:

According to HAARP's management, the project strives for openness and all activities are logged and publicly available. Scientists without security clearances, even foreign nationals, are routinely allowed on site. The HAARP facility regularly (once a year on most years according to the HAARP home page) hosts open houses, during which time any civilian may tour the entire facility. In addition, scientific results obtained with HAARP are routinely published in major research journals (such as Geophysical Research Letters, or Journal of Geophysical Research), written both by university scientists (American and foreign) or by US Department of Defense research lab scientists. Each summer, the HAARP holds a summer-school for visiting students, including foreign nationals, giving them an opportunity to do research with one of the world's foremost research instruments.

What that means is that even if you don't personally have the scientific knowledge to evaluate what they're doing, you could. If you're really concerned about it, you don't have to take it on faith that it's safe. Just learn the relevant science and look at their data for yourself. --Sean 14:34, 17 August 2010 (UTC)[reply]

The radio is basically a giant HAM antenna that puts out as much power as a reasonably large television station. Its effects on the ionosphere are measured by numerous independent scientists, to several decimal places; and these effects rarely persist more than a few seconds after the heater is turned off. Despite the conspiracy theories, the radio is not significantly affecting the ionosphere, or the atmosphere, or the weather, or even operating at a band where it would interfere with FM radio or television signals. When aircraft fly within a very conservatively estimated radius, the transmitter shuts down to make sure that it doesn't interfere with any of their communications or navigation equipment (though most flights in that region of Alaska are VFR anyway). Surprisingly, despite all the static HAARP gets for mucking with "mysterious radio waves", there are very few legitimate critiques of its massive carbon footprint: the 3.6 megawatts of diesel-generators spew noxious fumes into the otherwise pristine Alaskan air. The HAARP electric plant burns through a truckload or two worth of fuel during any hour of any given experimental run. Nimur (talk) 18:34, 17 August 2010 (UTC)[reply]

Sex in Mount Everest

No kidding, I was just thinking about the possibility of having sex in Mount Everest. The problem in having sex in Mt Everest is 1. low temperature, 2. lack of oxygen. The first will probably cause frostbite in the exposed part of the body, while sex in Everest without carrying an oxygen cylinder is difficult. So is it possible to build some type of tent over the peak where the temperature can be regulated for the purpose of sex? If possible, how the tent should be built? Using helicopters? --Galactic Traveller (talk) 06:08, 17 August 2010 (UTC)[reply]

First of all, please do not use "in Mount Everest" as it is grammatically (if not logically, or even scientifically) illogical. Please say "upon Mount Everest" or at least "on Mount Everest". Question of frostbite is of no consequence as there is no such rule that both partners should be wholly naked ( that's a Hollywood stereotype ). As far sexual organs are concerned, the penis will be inside the cunt ! How convenient. Now for something serious - Indian yogis have been known to do such things up there. They spent decades up there, it would be highly unlikely that they didn't do it. No ? Jon Ascton (talk) 12:46, 17 August 2010 (UTC)[reply]

Can I please ask that you keep to the vocabulary of civilised discourse, and use the scientific name "vagina" rather than the vulgar name "cunt"? 76.229.199.177 (talk) 15:56, 17 August 2010 (UTC)[reply]

maybe he was referring to the woman. 92.230.233.158 (talk) 21:17, 17 August 2010 (UTC)[reply]

PS I found a discussion [18] on this issue in Yahoo Answers, but I don't think the discussion there is scientific. --Galactic Traveller (talk) 06:12, 17 August 2010 (UTC)[reply]

Of course it is possible to build a tent on a mountain. It is possible to build a tent anywhere! This is not a scientific question. I suggest this question be deleted in the interests of maintaining this Reference Desk as a serious source of scientific debate. Dolphin (t) 09:03, 17 August 2010 (UTC)[reply]

Euophrys omnisuperstes[19] seems to manage without a tent. Sean.hoyland - talk 09:36, 17 August 2010 (UTC)[reply]

This question is indeed misfiled. But we should make a present of it to some other reference desk, but which? Humanities - entertainment - miscellaneous? As for the sex, it's best to wait until the Bihar-Kathmandu-Shigatse freeway is tunneled, then pull off at the Everest exit and take the elevator to the hotel. Ask for one of the honeymoon suites with the windows looking out of the mountain. Don't miss the Suicide Mountain tour, where you rent out a pressure suit and look at the corpses and primitive tools, but skip "Ghosts of Everest", which is just lame (aren't they always)? Wnt (talk) 12:53, 17 August 2010 (UTC)[reply]

Humans could create a normal environment on the moon or on Mars or on the peak of Everest, by having a pressurized and heated dome. Then they could do whatever they might do anywhere on Earth. "Inside Mount Everest" it would be far simpler, once the excavation was done. Dig a tunnel, insulate and seal it, then it is home sweet home, and you might as well be in a Super 8 Motel in Sidney, Montana. Now go to it. A little sweet talk and a bottle of wine might facilitate things. Edison (talk) 23:16, 17 August 2010 (UTC)[reply]

A little levity may be expected, since Everest is roughly 6 miles above the usual 4000-mile radius of Earth; squaring this ratio one might have nearly a 0.3% reduction in body weight. For a buxom bride that might be most of a pound! But that neglects the little detail that Everest is underneath a person, exerting the largest portion of the planet's gravity - so I suspect the weight reduction would actually not be so large. But has any luckless Sherpa ever dragged up the experimental apparatus to find out? Wnt (talk) 20:23, 18 August 2010 (UTC)[reply]

how can ?

I am a mech enng student from India. i want to know how we can convert the by products during combustion of fuel into a useful form? i means that how we can convert by products to a new energy source? then how we can reduce the pollution due to the exhaustion of unwanted gases. if u can help me my email id is xxx jibin abraham

^{(OP's email id and phone number deleted, following Ref Desk policy)} Jon Ascton (talk) 12:59, 17 August 2010 (UTC)[reply]

I have removed your personal contact information to protect it from third parties; all reference desk questions are answered here. Unfortunately, I don't know that you're likely to get much of an answer to your question from people on the internet. Discovering how to take internal combustion engine byproducts and turn them into useful fuel while reducing pollution is a guaranteed doctorate and all but certainly a Nobel prize -- it's also an open question. — Lomn 13:06, 17 August 2010 (UTC)[reply]

Lomn - that's a truly terrible answer. This is not remotely "an open question" - it's exceedingly well understood and it's flat out impossible. What comes out of a correctly tuned, modern internal combustion engine is almost entirely water, CO2, nitrogen and a few nitrogen compounds. None of these will produce energy for you because their constituent atoms already gave up their free energy inside the cylinders of the engine. So, no - the laws of thermodynamics prohibit any possibility of doing this. It is true, however, that a poorly set up engine will produce some carbon monoxide - which could (in principle) be persuaded to release a little more energy by reacting it with oxygen (which is what happens in the catalytic converter to eliminate CO - which is poisonous to humans). But as internal combustion engines have improved over the last 20 years, the amount of carbon monoxide they produce has become so small as to be essentially zero - and if any carbon monoxide is available, you would be better off engineering the car to run more efficiently and thereby not produce any carbon monoxide in the first place rather than trying to exploit it later. Encouraging our OP to waste time on trying to do this (in the hope of winning that Doctorate/Nobel Prize that you promised him) is downright irresponsible. This is a dead end subject - I strongly advise our OP to look for something more productive to work on. SteveBaker (talk) 15:43, 17 August 2010 (UTC)[reply]

Well, actually if you burn hydrogen, your exhaust is water (something useful, I'd say), and if you add enough energy (say in electrolysis), you can go back to fuel. --Stephan Schulz (talk) 17:53, 17 August 2010 (UTC)[reply]

If our OP was talking about hydrogen fuelled cars, then you'd certainly expect to see mostly water and nitrogen in the exhaust. But we know he's not talking about that because he's concerned about reducing pollution (which is notably absent in hydrogen cars). But in any case, using electrolysis to convert the water back into hydrogen and oxygen isn't going to create energy (as the OP specifies) - to the contrary, it'll consume significantly more energy than it produces. So that's still a dead end engineering-wise. If you have enough electricity on board your car to convert the water back into hydrogen, you'd do MUCH better by tossing out the hydrogen, the water and the internal combustion engine - and just making an electric car! So this too is a terrible answer. SteveBaker (talk) 19:56, 17 August 2010 (UTC)[reply]

Fuels work by converting one collection of chemicals to another that has a lower energy level. Organic fuels (fossil fuels, biomass, etc.) get converted to carbon dioxide and water, which are already very lower energy. There isn't really anything you can convert them to to extract more energy. You might be able to use them for some other purpose, but not as fuel. You may find carbon capture and storage interesting. --Tango (talk) 13:07, 17 August 2010 (UTC)[reply]

Yes, combustion releases energy from fossil fuels, turning them into low energy chemicals. About the only way to use the low energy chemicals as fuel is to add more energy to them, which won't be saving anything. --Chemicalinterest (talk) 13:11, 17 August 2010 (UTC)[reply]

A Catalytic converter (see article) converts fuel combustion products into nitrogen, oxygen, carbon dioxide and water. Cuddlyable3 (talk) 14:10, 17 August 2010 (UTC)[reply]

It doesn't produce energy, though, it just speeds up the breakdown of the products of impurities in the fuel. --Tango (talk) 15:32, 17 August 2010 (UTC)[reply]

I'd be very surprised if it did not produce energy. Of course, that energy goes away as useless heat. --Stephan Schulz (talk) 17:53, 17 August 2010 (UTC)[reply]

A catalytic converter simply burns partially burned fuel. It does nothing to fully burned exhaust. Ariel. (talk) 18:33, 17 August 2010 (UTC)[reply]

Modern "3-way" catalytic converters also convert NO and NO₂ back into nitrogen & oxygen. As it's name implies, the catalytic converter uses a catalyst to drive the reaction - there is no actual combustion (in the sense of flames & burning). The additional heat from those reactions is very small though - completely negligable compared to the waste heat produced by the engine itself. In the drive for more fuel economy, the amount of unburned fuel and carbon monoxide has gone WAY down over the last 10 to 20 years. If you wanted to reclaim energy from waste heat then you'd be better off doing something with the hot water in the radiator or with the heat of the exhaust gasses themselves. However, efforts to do that have been pretty ineffective to date...I've seen people try to use stirling engines to extract energy from those sources - but the results have been less than impressive. Probably the best use of waste energy from the exhaust is in cars with turbochargers where the pressure of the exhaust gasses are made to drive a turbine that pumps air into the cylinders at higher pressure and thereby allow more fuel to be burned in each cycle. The result is a more powerful engine - and this allows us to use smaller engines without sacrificing horsepower. That saves weight and therefore energy.

SteveBaker (talk) 19:56, 17 August 2010 (UTC)[reply]

I'm not sure if this actually works, but could CH₄ be burned in the absence of oxygen in such a way that it forms C₂ + 4H₂? The hydrogen in this case would be useful as hydrogen fuel. ~A H 1^(TCU) 23:40, 17 August 2010 (UTC)[reply]

We've running away here, but see [20] - the heat of formation of methane ΔHf_o(CH4) from carbon and hydrogen is -17.8 kcal/mol, which is to say, it liberates heat to do the opposite reaction. That page doesn't discuss entropy directly (though it looks like a nice web site which might somewhere else) but I doubt that the separate carbon and hydrogen are entropically favored. Also of course "C₂" doesn't exist per se, though it could be added to a mass of bulk carbon. Wnt (talk) 19:57, 18 August 2010 (UTC)[reply]

Leopard frogs

What's the difference between this and this? --Chemicalinterest (talk) 13:09, 17 August 2010 (UTC)[reply]

According to this, the Southern Leopard Frog has a "light spot in the center of its tympanum, a longer pointed head, and only a few dark spots on the side of the body" compared to the Northern Leopard Frog. Mikenorton (talk) 13:29, 17 August 2010 (UTC)[reply]

marine mammal biology

Tailfins of marine mammals such as whales are horizontal--tailfins of fish are vertical. Is a horizontal tailfin a unique characteristic of marine mammals? —Preceding unsigned comment added by 189.93.156.125 (talk) 14:09, 17 August 2010 (UTC)[reply]

More or less. It comes about because the tails of marine mammals are basically modified feet - where fish tails have always been tails. Some bottom-feeding fish appear to have horizontal tails - but this comes about because flat fish (like flounders) are essentially normal fish that have evolved to swim on their sides - so what looks like a horizontal tail is "really" a vertical tail laid sideways. However, this means that there are fish with horizontal tails - so you can't use that fact to determine whether a marine animal is really a mammal or a fish. SteveBaker (talk) 15:22, 17 August 2010 (UTC)[reply]

Have to disagree with you in one detail, Steve: most aquatic mammals' tails have nothing directly to do with their former rear limbs, which are (usually) vestigially present but buried in the body far forward of the tail region. Their tails are merely developments of the conventional tails their terrestrial ancestors had.

The reason that they are horizontal as opposed to the vertical tails of fish (and reptiles) is as follows. The spines and general anatomy of fish is such that they generally move by passing lateral (side-to-side) waves down their bodies (themselves often laterally flattened) from front to back: vertical tails are obviously most efficient in this context. When some fish developed limbs and colonised the land, giving rise to the common ancestors of reptiles and mammals, some retained their sideways-sprawling limbs and continued to flex their spines from side to side while walking, giving rise to the characteristic movement of, for example, most lizards, but others, including the ancestors of mammals, eventually evolved more vertical limbs and switched to the more efficient mode of flexing their spines vertically, enabling gaits such as galloping and bounding.

When some mammals later returned to the water, they retained this now built-in vertical spine flexing mode (see Marine mammal#Adaptations), and since a horizontally flattened tail is most efficient with this mode, that's how their tails developed. (I've just finished reading Richard Dawkins' The Greatest Show on Earth, which goes into this question explicitly.) 87.81.230.195 (talk) 17:45, 17 August 2010 (UTC)[reply]

Concur with 87.81. Note that the third character in the classic convergent evolution example of marlin, dolphin, ichthyosaur also has the vertical tailfin, though structurally completely different from that of the marlin. As a reptile, it still had the stereotypical sideways gait seen today in snakes and lizards and so benefited from the vertical tailfin, even though it had to essentially remake it from scratch. Matt Deres (talk) 19:32, 17 August 2010 (UTC)[reply]

Dolphins? All cetaceans and sirenians have horizontal tail-fins (or at least all the photos we have of them have). CS Miller (talk) 20:37, 17 August 2010 (UTC)[reply]

There is also a fish called dolphin. I think it is also called Mahi Mahi. Googlemeister (talk) 21:12, 17 August 2010 (UTC)[reply]

I don't think Matt meant that a (mammalian) dolphin has a vertical tail (which, of course, it doesn't). Rather that, of the three animals he mentioned - respectively a fish, a mammal, and a reptile - which have all converged on a very similar overall body shape, the fish has always retained its original sideways spine flexing and hence a vertical tail, the reptile has after returning to the water re-evolved a vertical tail because it had retained the sideways spine flexing during its land phase, but the mammal redeveloped its tail horizontally on becoming once more aquatic because it had developed vertical spine flexing while on land. 87.81.230.195 (talk) 22:03, 17 August 2010 (UTC)[reply]

Indeed. I can see how I was a little unclear, but but when I said "third", I made sure ichthyosaur was the third thing on the list I gave. :-) Matt Deres (talk) 00:25, 18 August 2010 (UTC)[reply]

I don't know if it's helpful to mention that some marine mammals, especially seals like the harbor seal, do use their fins oriented vertically in a side-to-side motion like fish do. These seals do have their rear fins derived from hind limb structures, whereas cetaceans have rear fins derived from the tail of the spine rather than rear limbs (note the location of the undeveloped hind limbs (C) in this skeletal image: http://en.wikipedia.org/wiki/File:Whale_skeleton.png forward of the fluke.) —Preceding unsigned comment added by Wevets (talk • contribs) 05:25, 18 August 2010 (UTC)[reply]

Just so, hence partly the 'most' in my earlier post. These rear fins aren't strictly 'tailfins' which the OP asked about, but some might confuse the two, so your clarification is timely. 87.81.230.195 (talk) 09:08, 18 August 2010 (UTC)[reply]

Small-scale carbon sequestration using phytoplankton?

Hi. I'm investigating common-sense and small-scale approaches to carbon offsetting, and have been asked to look into the potential of micro sequestration as a carbon offset. One approach that has come up in discussion is the growing of cultures of phytoplankton. I've found information intended for aquarists that shows it is relatively easy to grow a culture of phytoplankton, particularly for people on the coast. However, I'm finding it very difficult to obtain any information as to how effective these plankton are at sequestrating carbon in small quantities: a figure for mass or volume of plankton per tonne CO2e, for example. I recognise that this is unlikely to be cost effective and may require totally massive amounts of plankton, but I have no frame of reference at all, so it can't hurt to ask! Whether it's a good idea or not, for the sake of completeness I'd like it in my report, so it would be very helpful if anyone knows anything that might point me in the right direction.

Thanks much! Dan Hartas (talk) 14:33, 17 August 2010 (UTC)[reply]

It is going to heavily depend on what happens to the plankton. In the wild, studies suggest that only a small fraction of plankton biomass is sequestered, while most is eaten and recycled by other organisms. If you intend to collect the plankton and bury them (or something) you could trap more carbon, but that would depend on specific human intervention. Plankton are about 0.3 grams carbon per 1 gram dry weight [21], so 1 tonne CO2 could make about 900 kg of plankton (dry weight) assuming all other conditions were favorable. In practice though, I would suspect that plankton growth is nearly always limited by other nutrients (e.g. Fe, P) and not by CO2, so you'd have to supply such nutrients to get them to grow in abundance. Dragons flight (talk) 17:54, 17 August 2010 (UTC)[reply]

The real problem with plankton (although you didn't ask) is that they are decomposed by bacteria. Furthermore, those bacteria take up oxygen in the process of decomposing the plankton. If the quantity of plankton is high enough to overcome the amount of decomposition, then the water becomes almost completely anoxic, killing most if not all animal life. Looie496 (talk) 23:52, 17 August 2010 (UTC)[reply]

Dragons flight, that weight stuff is for zooplankton, not phyloplankton, unless I've misunderstood. The nutrients aren't a problem, apparently ordinary plant food has everything they need. And on Looie496's point, would that happen in small-scale circumstances? It sounds like you can grow a culture of these things in about two weeks, though I haven't yet tried it myself. Would that be enough time for the decomposition to have a significant effect? Dan Hartas (talk) 08:51, 18 August 2010 (UTC)[reply]

It's not the bacteria you need to worry about, but viruses - they manage to kill off algal blooms and so if they got into your culture you'd be screwed. You might be better off seaweed farming as it would be a lot easier to harvest than microalgae and kelp can be extremely productive. Smartse (talk) 16:22, 18 August 2010 (UTC)[reply]

Gene copy number: human genes that are rarely deleted or duplicated?

I haven't been able to find anything definitive in the primary literature, so I thought I would pick the brains of the RDD (reference desk denizens). I'm planning an experiment in which I use real-time PCR to estimate the viral copy number of HPV infected tissues by comparing the viral DNA to reference one or more host genes. Many of these tissues, however, exhibit considerable chromosomal instability, so it's important that I'm comparing the HPV numbers to human gene that are unlikely to change in copy number (either up or down). It is safe to exclude any considerations of a Y-chromosome here. Does anybody know of any genes that are especially unlikely to be either deleted or duplicated (i.e., not have a copy number other than 2)? Thanks! – Clockwork Soul 15:14, 17 August 2010 (UTC)[reply]

This doesn't really answer your question, but is there a reason that you want the HPV copy number to be relative to the host copy number? Why not just generate a standard curve of HPV copy numbers and then determine the absolute copy number (or copies per microgram of input DNA) in your sample? --- Medical geneticist (talk) 18:22, 17 August 2010 (UTC)[reply]

Normally, that's what I would do since what I really want is the average virus count per cell, but there are two problems. First, I don't necessarily know how many cells I'll have, largely because of the difficulty in resolving cell numbers from microdissected FFPE (formalin-fixed, paraffin-embedded) tissue. Second, many of my higher grade samples have large-scale chromosomal anomalies (deletions, duplications) that make "copies per microgram of DNA" unreliable. The qPCR alternative works well enough, though, assuming there are really as many "baseline" copies of the human genes as you think. – Clockwork Soul 19:32, 17 August 2010 (UTC)[reply]

It's a little hard to answer your question without a detailed understanding of the system you're using (for example, how dramatic is the chromosomal instability) but it would be hard to imagine any single site being absolutely stable if there is enough instability to significantly affect the average amount of DNA per cell. How about using a selection of sites across multiple chromosomes and averaging them? You could choose pre-made real-time PCR primer pairs or probes for various "sequence tagged sites," which already have well-established primer pairs. --- Medical geneticist (talk) 02:30, 18 August 2010 (UTC)[reply]

The try-a-few-and-see approach seems most straightforward; all I can add is that the cytology for most tumor types has been well studied (e.g. cervical cancer is known to have amplifications at 3q26 and 8q24 (PMID 19626623), so you could try to avoid trouble spots. You could also use a standard curve. (PMID 16061973) Another approach might be to use a sequence you know is present in many copies (Alu, for example (PMID 17316233, PMID 16775168), though unless the virus is present in very large abundance it might be better to compare to a less common repeat. Wnt (talk) 14:24, 18 August 2010 (UTC)[reply]

House revisited

Hey, it's me from a few days up. How accurate medically is House M.D., overall. I've read Dr Scott's Polite Dissent blog and it seems to focus more on minor things from individual episodes rather than the 'big picture'. The impression I get is that sometimes the directors/writers will take some artistic license and sacrifice afew technical details for entertainment, eg the characters sometimes don't wear eye or face protection in surgery because it would obscure their facial expressions and thus their emotions, or the effect of a medicine is exaggerated to bring closure to an episode, or they run a culture and it comes back 2 hours later inconclusive so they move on to keep the plot moving, rather than the more realistic they run a culture it grows for 2 weeks and comes back inconclusive, they do it again, and then they move on, you get my point. But I saw an episode where a patient with a brain-dead right hemisphere couldn't see in his right eye but was fine in his left, a basic mistake, thus, here were are. --Anon. 18:25, 17 August 2010 (UTC)—Preceding unsigned comment added by 76.229.199.177 (talk) 18:25, 17 August 2010

Old discussion may be slightly relevant, though it doesn't answer your question directly. 90.195.179.60 (talk) 19:16, 17 August 2010 (UTC)[reply]

I can't speak to the accuracy of their medical facts, but in terms of basic procedure I think the show is pretty awful. The doctors there just don't behave the way that people trying to solve a difficult problem really behave. They never seem to concentrate on what they're doing, they just come out with ideas, one after another without pausing. You could say it's just drama, but the old ER show was far better (in the early years at least), and more dramatic too. Looie496 (talk) 23:40, 17 August 2010 (UTC)[reply]

There are enough fragments of accurate medical information to classify House as a "medical drama" but the writers take significant liberties with the process of medical diagnosis and treatment, with the result that the show ends up being not much more than a caricature of the medical profession. It's really just a soap opera. I heard a lecture by an M.D. who serves as an adviser to the show, and he described the writing process as something like this: 1) the writers have an idea for a thread to develop some aspect of a character, 2) they consult with the medical advisers to identify a medical condition that could present in an unusual way and allow for a number of different diagnostic possibilities, 3) the writers take the idea and run, and 4) shortly before they start filming the episode the medical advisers check to make sure that there aren't any egregious errors (keeping in mind that it's ok for any aspect of the diagnostic process and/or treatment to be far-fetched or temporally inaccurate for the sake of the thread of drama). Basically, the medical aspect of the show is merely a vehicle for the actors to portray the characters, and should not be taken as anything much more than that. --- Medical geneticist (talk) 02:49, 18 August 2010 (UTC)[reply]

One should give them credit for having advisers. Compare CSI - I've watched two episodes of that, and in one a killer was harvesting drug addicts for the heroin in their brains, and in the other someone was electrocuted because current from a cable buried in the sand arced up to his heart because someone wrote something on his chest in conductive ink. What's next, a killer who breaks into high-rises by climbing the beam of his partner's flashlight? (oh no, I just gave them an idea... Wnt (talk) 14:29, 18 August 2010 (UTC)[reply]

Genes and Genomes

How is a gene different to a genome? --T.M.M. Dowd (talk) 19:18, 17 August 2010 (UTC).[reply]

Our gene and genome articles are pretty thorough. – Clockwork Soul 19:22, 17 August 2010 (UTC)[reply]

Put simply, a Gene is a small piece of genetic information that codes for a specific trait. I have a gene that makes my eyes blue, my wife has a different gene that makes hers brown. A Genome is all of the genetic information that makes up an organism - thousands to hundreds of thousands of genes. It's a little more subtle than that - but that's the "Big Picture" explanation. If you need more - look up the articles. SteveBaker (talk) 19:32, 17 August 2010 (UTC)[reply]

Put even more simply: An organism's genome is made up of genes. The Human Genome Project, then, was an attempt to map all of the genes in a human genome. (Well, a number of humans, but that's a bit beyond the point.) --Mr.98 (talk) 21:49, 17 August 2010 (UTC)[reply]

NO! You have many genes controlling eye colour - Eye colour#Genetic determination of eye color (this has some examples where you could say you and your wife have different genes). Smartse (talk) 16:31, 18 August 2010 (UTC)[reply]

Steve and his wife could differ in only a single gene and still have different eye colors as he described. While a single gene is not solely responsible for determining eye color in humans, it's not incorrect to say that it would govern the determination in their particular case — a single genetic difference could be sufficient to alter the observed phenotype. Heck, cut him a bit of slack — he noted that he was giving a high-level explanation. TenOfAllTrades(talk) 16:59, 18 August 2010 (UTC)[reply]

A gene is a single instruction. A genome is the entire instruction manual. --Jayron32 04:37, 18 August 2010 (UTC)[reply]

A gene is a bit like a recipe for making a particular protein, a genome is like a recipe book that holds all the recipes together and allows your cells to use the recipes. Smartse (talk) 16:31, 18 August 2010 (UTC)[reply]

Bouncing orbit

I'm trying and failing to locate an article. Maybe it doesn't exist. List of orbits didn't help.

Many years ago, I read a novel of hard science fiction, written by a scientist (I recall), in which a megalomaniac religious leader devised a hammer-of-god-like threat to the world that involved something the novel referred to as a "bouncing orbit".

In this scheme, a two halves of large mass are positioned above a pole of the Earth and allowed to fall straight down. If the religious leader chooses to allow it, at a predetermined time powerful electromagnets push apart the two halves with sufficient force for them to pass by the planet and meet again over the other pole. The electromagnets recharge themselves from the two half-masses coming together. When they meet, the combined mass continues upward away from the pole until it begins falling again.

This "orbit" has the center of mass bouncing up and down through the planet's center. I thought it was an interesting idea when I read it. The sources I can find, however, seem to be use this term in the context of subatomic particle interactions.

Thinking about this caused me to wonder if the acceleration experienced by the center of mass, orbiting this way, is the same as if the mass fell through a small hole bored straight through the Earth. ~Amatulić (talk) 20:26, 17 August 2010 (UTC)[reply]

Well, it isn't really an orbit if it requires powerful electromagnets. Orbits are what objects in free fall follow. I doubt you'll find an article on the subject, since it probably only exists in that one story. Someone might recognise the plot and be able to find an article on the book, but that's the best you'll get. The centre of mass will be exactly the same if the mass fell through the Earth rather than going around it, since the vertical components are the same and the horizontal components of the two halves cancel out. --Tango (talk) 21:33, 17 August 2010 (UTC)[reply]

That's what I thought. Thanks. ~Amatulić (talk) 21:53, 17 August 2010 (UTC)[reply]

But that answer is wrong. When the line between the two halves does not pass through the Earth, the force on the two halves is less than if they were united, for two reasons. First, they're farther from the Earth's center. Second, the force on each one is angled toward the Earth's center. For example, say that the objects' center of mass is 6,000 miles from the Earth's center and they are 9,000 miles apart, or each 4,500 miles from their center of mass, conveniently making a pair of 3:4:5 triangles. Then each object is 7,500 miles from the center, so the force on it is (60/75)² of what it would be if they were united at their center of mass. And if we resolve the force into "vertical" (parallel to the Earth's axis) and "horizontal" (toward the other half) components, only 60/75 of the force is vertical. So the center of mass, at that instant, is accelerating by just (60/75)³ = 0.512 times as much as it would be if the objects were united.

When the line between the two halves does pass through the Earth, the calculation is more complicated because now the two halves are attracted by the full Earth whereas if they were united they would be attracted only by the inner part of the Earth (the part closer to the center). Since the question was only "is the acceleration the same", I am not going to determine by what amount it's different; but it will in general be different.--Anonymous, 22:58 UTC, August 17, 2010.

I haven't gone through your maths, but it seems unnecessarily complicated. The centre of gravity of the two halves is the same in both cases and the centre of gravity of the Earth and the two halves must be constant, since there are no external forces, therefore the centre of gravity of the Earth must be the same in both cases. That means its acceleration must be the same. --Tango (talk) 23:05, 17 August 2010 (UTC)[reply]

Tango, please do "go through the maths" before making wrong statements. Only for a spherically symmetric mass is it true that the force of gravity is equivalent to what it would be for a point mass on its center of gravity. --Anon, 11:35 UTC, August 18, 2010.

The orbital period depends only on the semimajor axis - an object that almost brushes past the Earth will have the same period as one that orbits in a circle. That said, separating two halves of a mass with electromagnets does change the orbit... to give an extreme example, if they are given near-escape velocity they would move out to a large distance and could take as long as you wish for them to fall back. Wnt (talk) 00:49, 18 August 2010 (UTC)[reply]

is this (arch of books) real?

is this real? (arch of books). why don't the books at the top fall down? The one in the middle of the top is vertical and can fall straight down if not glued - why doesn't it? 92.230.233.158 (talk) 20:51, 17 August 2010 (UTC)[reply]

The keystone book you refer to would not fall down due to fricton from the books on each side. The weight of each side of the arch is pushing on each side of that book.

There's no reason why it can't be real. I have built free-standing arches like that out of wooden blocks. ~Amatulić (talk) 21:13, 17 August 2010 (UTC)[reply]

so if you take that book out because that's the one you need, the whole thing would crash down? Doesn't sound as useful as it looks anymore. 92.230.233.158 (talk) 21:15, 17 August 2010 (UTC)[reply]

More likely, because that book is so thin, removing that center book may cause each side of the arch to fall toward each other a little bit, leaving another book in the center. Generally a keystone is a significant piece of an arch, the key that keeps it together. No, an arch of books isn't useful if you happen to need any of the books, not just the top center book.

Our article on keystone is incorrectly referenced; the keystone is no more important structurally than any other piece of the arch. It's only the "key" stone because it's the last piece to be put in place. Frankly, it's probably less important than the other pieces; if you were to remove it, the two sides would collapse into a semi-stable arch-like shape. If you removed a piece at the bottom... I'm looking for a proper reference, but the word keystone seems to have been completely co-opted by the ecology folks. Will keep looking. Matt Deres (talk) 00:32, 18 August 2010 (UTC)[reply]

In the building of bridges and other arches, the keystone is usually specially shaped and the material is chosen very carefully to ensure that it can withstand the forces. I agree, however, that other components of the arch are also important to stability.

The Arch article goes into some detail about different constructions of an arch. ~Amatulić (talk) 21:31, 17 August 2010 (UTC)[reply]

While some such arch might work in theory, I'm skeptical of some features of the photo. It seems like some of the books are separated by wedges - I don't think it's purely made out of books. The center book seems to spread out toward the back of the arch rather than upward as one would expect of a keystone. And the sides of the arch are perfectly level - you'd think that the pressures involved in an arch would bow those stacks outward; they're not masonry blocks. My guess is that it's a typical artistic assemblage with many compromises in execution. Wnt (talk) 00:53, 18 August 2010 (UTC)[reply]

Furthermore, if you compare the book arch with the first illustration in Arch, the most obvious things missing are the abutments, which would stop the vertical stacks being pushed outwards. The book arch must have hidden reinforcement to stop this from happening. --Heron (talk) 08:08, 18 August 2010 (UTC)[reply]

Afterburners

Hello. Our article on afterburners says that extra fuel is injected after the turbine (which is most of the engine). Can someone tell me exactly where the extra fuel is injected? --The High Fin Sperm Whale 21:09, 17 August 2010 (UTC)[reply]

For the General Electric J79 they're shown as item #17 on this diagram "afterburner spray bars". -- Finlay McWalter • Talk 21:15, 17 August 2010 (UTC)[reply]

Another diagram. The afterburner is the vertical column of "<" symbols labeled "8".

The fuel is injected after the turbine. :)

"Turbine" in this instance refers the turbine fan assembly. Behind that there's a hollow chamber with a nozzle at the very back end. Afterburner fuel is injected behind the aft fan of a turbine jet engine, but before the nozzle. ~Amatulić (talk) 21:16, 17 August 2010 (UTC)[reply]

In the combustion chamber? --The High Fin Sperm Whale 21:31, 17 August 2010 (UTC)[reply]

No, the combustion chamber is forward of the aft fan. The afterburner is between the aft fan and the nozzle. The combustion chamber is where fuel normally combusts and expands, being forced out the nozzle in back. The exhaust gases pass over the aft turbine fans to drive them, which in turn drive the forward compressor fans for sucking in more air. That's why jet engines are known as "continuous combustion" engines, as opposed to intermittent combustion as in a piston-powered internal combustion engine. ~Amatulić (talk) 21:51, 17 August 2010 (UTC)[reply]

High Fin Sperm Whale has written after the turbine (which is most of the engine). This is incorrect. Most of the engine is forward of the turbine. The only component aft of the turbine is the nozzle. A jet engine consists of diffuser, compressor, combustion chamber, turbine and nozzle, in that order. Dolphin (t) 11:20, 18 August 2010 (UTC)[reply]

Mutation in genetic algorihms

It is not mentioned in the Wikipedia article where the mutation operation is used in the genetic algorithm. Let's say there are N chromosomes in the last step. (I say them old N chromosomes) I think that there are three different choises.

1) N new chromosomes are generated by three operations: a) Some are directly copied from initial population b) Some are generated by crossover c) Some are generated by mutation.

2) N old chromosomes enter crossover and after mating and crossover N new chromosomes are generated. Only N new chromosomes enter mutation, not new N chromosomes.

3) N old chromosomes enter crossover and after mating and crossover N new chromosomes are generated. Both N old and N new chromosomes enter mutation.

Can all three methods work? Or which one is true? Kavas (talk) 21:18, 17 August 2010 (UTC)[reply]

Any of these will work just fine, and there's no standard timing for mutation in a genetic algorithm. My own choice would be to copy/mutate, and then cross over since that could generate the most novel combinations, but it's entirely a design decision. Good luck! – Clockwork Soul 21:35, 17 August 2010 (UTC)[reply]

Thank you. But, what's copy/mutate? Kavas (talk) 21:46, 17 August 2010 (UTC)[reply]

It's important to limit the rate of mutations, or you get mutational meltdown. When you take that into account, I don't think it matters which technique you use. Looie496 (talk) 23:25, 17 August 2010 (UTC)[reply]

By copy/mutate, I just meant that if I were writing this, I would choose to generate mutant chromosomes and group them with the "old" chromosomes as a single population prior to sending them to the crossover routine. Just my personal preference, though. Again, though, all of these approaches are perfectly adequate and will all give you results. Looie496 is right though: mind your mutation rate! – Clockwork Soul 18:34, 18 August 2010 (UTC)[reply]

What is this tree?

Photographed in Hampshire, England. Kittybrewster ☎ 21:58, 17 August 2010 (UTC)[reply]

Unsure, but could it be a type of Ailanthus? ---Sluzzelin talk 22:52, 17 August 2010 (UTC)[reply]

Maybe also a Fraxinus (Ash) species? While not the only tree family with compound pinnate leaves, its usually highly associated with the Ash family. You'd have to check to see if the leaves are simple pinnate (i.e. each leaf is an individual leaf, with its own anchor point) or compoundly pinnate (i.e. the central "stem" of the cluster of leaves is really the main vein of the leaf, and each seperate "leaflet" isn't a seperate leaf, but part of the compoundly-pinnate structure). The latter compoundly-pinnate structure is usually most closely associated with Ash trees. --Jayron32 04:34, 18 August 2010 (UTC)[reply]

I think it has too many leaflets per leaf for it to be an Ash (at least based on the pictures in our articles), the new shoot also doesn't look like those of ash that I can find either. Whereabouts was the photo taken? Do you know anything else about it, like height, colour of flowers etc.? User:Smartse

Photo taken in a garden at late dusk. It is as high as a three-storey house. Colour of flowers not known. Kittybrewster ☎ 16:46, 18 August 2010 (UTC)[reply]

Then I still think it might a tree of heaven Compare google pics for Ailanthus + gardens + England. ---Sluzzelin talk 16:50, 18 August 2010 (UTC)[reply]

Agreed Sluzzelin - you win the cigar - the odius Tree of Heaven it is. It's set to take-over England if the papers are to be believed[22]. Alansplodge (talk) 17:23, 18 August 2010 (UTC)[reply]

Optics: 35mm focal length equivalent

Hobbyist filmer here. I'd like to make mind-blowing ultra wide-angle images like Terry Gilliam, but in the more economical format of Super 8 mm film. What I do know is that I'm not even remotely looking like Gilliam with any focal length above 18mm...but that's my desired upper length in 35mm only. The focal length to achieve a particular angle of view (which is the thing that makes for the mind-blowing images with wide-angle images) is different with any format and sensor size you use, hence there's articles such as 35 mm equivalent focal length and crop factor. In other words, if you change the format (i. e. size of your film or sensor) but wanna have the same angle of view, you need a different focal length.

Now, I have a chance of acquiring a lens (for a Super8 camera made by the Austrian Eumig brand) which is labeled as ultra wide-angle, according to trade press this lens is guaranteed to be entirely rectilinear (no barrel aka fish-eye distortion, as I don't want this), and its focal length in Super8 is 4mm.

So what I'd like to know is, what's the 35mm equivalent of these 4mm in Super8, according to crop factor? Or in other words: If my desired upper limit is an 18mm focal length in 35mm, what equivalent focal length would that be in Super8?

I guess what might help are the dimensions of the Super8 frame area: 5.97mm horizontal x 4.01mm vertical, compared to 22mm horizontal x 16mm vertical in 35mm.

My second choice would be a 3CCD miniDV with a 1" chip size. What's the equivalent to 18mm there? --79.193.41.61 (talk) 22:39, 17 August 2010 (UTC)[reply]

Your 4mm Super8 lens would be approximately equivalent to a 15mm lens in 35mm format. When you halve the linear measurements on the sensor size, you double the effective focal length of the lens in terms of angle of view. Chip sizes are generally expressed in diagonal, so for a standard 3:2 aspect ratio, your 1" chip has dimensions of approximately 21mm x 14mm. That's almost the same as 35mm; the 18mm-equivalent would be around 17mm, maybe a little less depending on the aspect ratio. Thegreenj 22:41, 18 August 2010 (UTC)[reply]

Identify this snake

Hi. I saw a snake today in Southern Ontario, on a road near a canal, about 20 inches long with black and bright yellow stripes. What snake is this? I don't have any pictures. Thanks. ~A H 1^(TCU) 23:29, 17 August 2010 (UTC)[reply]

Was it striped laterally? In that case it could have been Butler's Garter Snake. ---Sluzzelin talk 23:33, 17 August 2010 (UTC)[reply]

The stripes on the snake in that picture I would describe as wheat-coloured and yellowish-brown. The snake I saw had about as much yellow as black but the striping pattern was basically the same, and it was more of a neon-yellow than a yellowish-brown. The Butler's Garter Snake was the result I got from looking at a snakes of Michigan webpage, but so far I don't think that was it. ~A H 1^(TCU) 02:13, 18 August 2010 (UTC)[reply]

The article does describe a range: "three yellow to orange stripes along the length of the body. The background color can range from brown, black or olive". Google has blacker and brighter examples. [23]. ---Sluzzelin talk 03:25, 18 August 2010 (UTC)[reply]

I guess it could also have been a different species from the garter snake genus (Thamnophis). The Common Garter Snake, for example, comes in different varieties too. Not all seem to have red markings, and some are blacker than others. Not sure about the "about as much yellow as black" part. The yellow stripes look thinner than the dark ones on virtually all the snakes I googled. ---Sluzzelin talk 11:49, 18 August 2010 (UTC)[reply]

This Common Garter Snake was photographed in Ontario. ---Sluzzelin talk 11:52, 18 August 2010 (UTC)[reply]

And here's one more garter snake candidate: A ribbon snake. If so, most likely Thamnophis sauritus septentrionalis (Northern Ribbon Snake). ---Sluzzelin talk 16:35, 18 August 2010 (UTC)[reply]

August 18

Blood arc?

Hi,

While shaving over a stopped porcelain sink, i accidentally nicked myself. A few drops fell into the water and I noticed that around the edge where the water met the porcelain, the blood appeared to arc (picture a solar-flare) up the wall on the sink then back down. Is this some form of diffusion? What is this phenomenon called? TIA PrinzPH (talk) 00:52, 18 August 2010 (UTC)[reply]

A guess: The drop of blood landed on the edge of the sink, and the edge of the drop left a half circle of blood. The rest of the droplet hit the water and caused the water to splash back up (have you ever seen that in slow motion?) and that water washed some of the blood, leaving the arc. Ariel. (talk) 02:22, 18 August 2010 (UTC)[reply]

I'm not a shill, but a modern razer (think of the brand name yourself) wouldn't cut you like that (unless you use the same one for six months or something). 92.230.233.158 (talk) 08:38, 18 August 2010 (UTC)[reply]

Oh yes it would. The new ones give you the worst cuts, too, if you're not careful. --Dr Dima (talk) 09:01, 18 August 2010 (UTC)[reply]

Origin of "Global Health"

I'm looking for info on the origins of the term "global health". To my understanding, this is a relatively new term meaning public health on a global scale; i.e. accounting for the threat posed by pandemics, mass migration, climate change, etc. Any idea where the term was first used and what public health/philosophical agenda is behind it? --Whoosit (talk) 03:18, 18 August 2010 (UTC)[reply]

This article provides some context, including a statement in the second paragraph of the introduction regarding its origins in the 1970s, and then citing a relevant article on "Global Health" and the WHO (PMID 16322464). The latter, in full text here, provides data and speculation directly addressing your questions (it's a complex issue and the article is freely available, so I won't try to summarize here). -- Scray (talk) 12:15, 18 August 2010 (UTC)[reply]

Might this be related to the concept of Gaia's health? ~A H 1^(TCU) 13:37, 18 August 2010 (UTC)[reply]

Thanks both. That article is a good start. Astro, I think global health is more of a gloabalist extension of public health, i.e. concern for welfare of human populations (which implies human populations are the source/origin of human diseases), where the Gaia health notion is one of ecology and systems biology, i.e. concern for the welfare of the biosphere as a whole and how this affects human populations (which implies an unhealthy environment is the source/origin of disease) --Whoosit (talk) 14:51, 18 August 2010 (UTC)[reply]

To give an example, the Global Health Council was named "National Council of International Health" until 1998.[24] Surprising that it took them so long to change a name like that. Wnt (talk) 16:41, 18 August 2010 (UTC)[reply]

How does an Epipen helping with an allergic reaction?

How does shooting epinephrine help someone who is allergic to bees and gets stung by one? Does the person still need to see an emergency room after using an Epipen? Thanks! —Preceding unsigned comment added by 76.169.33.234 (talk) 05:57, 18 August 2010 (UTC)[reply]

According to Anaphylaxis#Management, epinephrine (aka Adrenaline) is the standard treatment for anaphylactic shock for any allergic reaction, not just bee stings. Since the things about anaphylaxis that can kill you (mainly airway restriction and loss of blood pressure) are directly combated by epinephrine (mainly by opening airways and raising heart rate and blood pressure), its a logical and consistant treatment. To answer your second question, ABSOLUTELY, if anyone has a severe alergic reaction to anything, they should immediately be seen by a medical professional. Epipen is basically designed to combat the immediate, life-threatening aspects of anaphylaxis, but in no way does this mean that the danger has dissapeared or dissipated. --Jayron32 06:04, 18 August 2010 (UTC)[reply]

Also, people often carry more than one epipen because the first isn't always enough. If one doesn't always work, there is no reason to think that two will always work. You should always call an ambulance for anyone showing signs of anaphylactic shock. --Tango (talk) 07:09, 18 August 2010 (UTC)[reply]

Hell, even if it works the absolute best it can, you still need urgent medical attention. The epipen, like CPR, is just a way of (hopefully) surviving until medical help arrives. 86.164.66.83 (talk) 10:42, 18 August 2010 (UTC)[reply]

In many places the epinephrine pen injector requires a prescription; in that situation, the user should follow whatever instructions they were given by the prescribing provider and on the package (rather than ones provided anonymously here on Wikipedia, for example). -- Scray (talk) 12:08, 18 August 2010 (UTC)[reply]

Some of the above is straying toward the sort of "medical advice" that Wikipedia editors aren't trusted to give and readers shouldn't count on; but to get back to the question, the reason is that adrenaline (= epinephrine) in the EpiPen is a simple catecholamine hormone that has evolved as part of the fight-or-flight response, which puts top emphasis on maximizing heart and lung function for crisis situations. It's one of the major products of the adrenal glands, two little "epipens" nearly everyone carries. (If you can pay attention when something scares you, I think you can actually feel the adrenals inject their product into your bloodstream, but I might be misattributing the sensation) I think that this means that anaphylactic shock is not one of those situations where the only thing to fear is fear itself, and the victim needs to be calmed with gentle words and reassured that help is coming - rather, the hormones that come with the fear should be a lifeline. But I didn't quickly find a good source for this; here's one perspective about the idea. [25] Wnt (talk) 14:51, 18 August 2010 (UTC)[reply]

Whoa whoa whoa! Beware of that article. Not only is it written with a few weird points of confusion, that suggest a layperson trying to summarise things they've read and didn't completely understand, but the bit at the end about fear isn't actually talking about what you were talking about. The end of the article is talking about conquering your fear that you will have a reaction and go into shock so that you can actually take action to avoid the allergen and prepare for if you have a reaction. It acknowledges that some level of fear is rational and necessary to motivate yourself to act appropriately. It is not about conquering or using fear once you have gone into shock. Frankly, if you're going into anaphylactic shock, you probably don't have time to decide what level of fear is appropriate or helpful.

If you have an epipen or similar, you can consult the pamphlet that came with it, your chemist (at least in the UK), and your doctor. There are also various organisations which try to provide accurate and up-to-date information based on medical concensus. An example in the UK would be the NHS or the Anaphylaxis Campaign. 86.164.66.83 (talk) 22:11, 18 August 2010 (UTC)[reply]

Voyager 2 propulsion

What kind of propulsion used by Voyager 2? And is it the same propulsion used by Voyager 1, Pioneer 10, and Pioneer 11? How they avoid space debris or asteroids in their way? Do they have wings to steer it? Is it controlled by man or done automatically? What frequency they used for communication? Thanks... roscoe_x (talk) 06:10, 18 August 2010 (UTC)[reply]

According to Voyager 2, it is identical to Voyager 1. According to Voyager 1, the probe uses Gravity assist as its main means of propulsion. Voyager Program#Power discusses other power systems on the craft. --Jayron32 06:19, 18 August 2010 (UTC)[reply]

As for debris and asteroids, I'm going to make an educated guess that they simply don't need to. Outside of low Earth orbit, the density of space debris is very very small. The dense asteroid fields imagined in Star Wars and countless other movies and video games don't exist. Someguy1221 (talk) 06:25, 18 August 2010 (UTC)[reply]

Yeah, there's almost nothing in space. I seem to recall that sometimes spacecraft going through the asteroid belt will have their courses adjusted in order to make them fly by an asteroid close enough to take a picture. Paul (Stansifer) 12:46, 18 August 2010 (UTC)[reply]

I think the original poster is imagining that these spacecraft are being continuously propelled, like some science-fiction ones. That is wrong. They were launched by rockets originally, and they carry small rockets that were used to refine their course to reach the relevant planets. But for the most part, and probably all the time since their last planetary encounters, they are just moving in free fall. --Anonymous, 23:41 UTC, August 18, 2010.

Also note that wings don't do anything in space. Wings need air to be functional. - Akamad (talk) 13:44, 18 August 2010 (UTC)[reply]

NASA Jet Propulsion Laboratory's official Voyager webpage has technical information. The high-gain antenna received S-band uplink and transmitted X-band downlink. The S-band also participated in the Radio Science Experiment, in which the communication-data radio-signal was analyzed. The RSS website explains the spacecraft radios pretty thoroughly: S-band receiver (2115 MHz nominal frequency) and transmitters at both S-band (2295 MHz nominal) and X-band (8415 MHz nominal). Exact frequency (as received at Earth) was measured to 1/1000th of a Hz and varied with spacecraft/earth relative velocity and plasma-properties in the interplanetary space. As you may recall (those of you who closely followed the Voyager mission sequence - I wasn't quite alive yet) - there was a malfunction in the transmitter on one of the spacecraft in the early 1980s, and it was only by carefully loading new software code into an image-processing computer that the redundant transponder was made to work (I have a whole book on this, I can post more when I get home). Nimur (talk) 18:10, 18 August 2010 (UTC)[reply]

I think that the reference to a transmitter failure here may possibly be an erroneous recollection of the Galileo spacecraft rather than one of the Pioneers or Voyagers. Galileo's main antenna, which was stored compactly inside the spacecraft during launch, failed to open properly and they had to use a secondary antenna with a much lower data rate, and I remember they did some special programming to partially overcome that limitation. --Anonymous, 21:15 UTC, August 18, 2010.

No real propulsion was on board. For corrections 90kg of hydrazine monopropelant was on board. 16 0.89 Newton and 4 22.2 Newton rocket motors are on board, which used nearly 60 kg of the fuel till 2000.--Stone (talk) 18:43, 18 August 2010 (UTC)[reply]

All four space crafts used a very similar propulsion system.--Stone (talk) 18:47, 18 August 2010 (UTC)[reply]

the role of condensed milk in the imbibement of coffee?

What is the role, chemically, olfactorily/gustatorily, of the supplementation of condensed milk in the imbibement of coffee process? —Preceding unsigned comment added by 92.230.233.158 (talk) 08:35, 18 August 2010 (UTC)[reply]

Adding condensed milk to coffee is said[26] to soften the taste. Wikipedia has articles about Condensed milk and Coffee. Condensed milk has advantages over ordinary milk of indefinite storage life, and less cooling effect on one's hot coffee than adding cold milk. Cuddlyable3 (talk) 10:02, 18 August 2010 (UTC)[reply]

I don't think it's a scientific matter, but condensed milk usually includes sugar, and logically it requires less dilution of the coffee (or more in the cup to start with) for the same amount of milk components added. Wnt (talk) 16:48, 18 August 2010 (UTC)[reply]

What is the primary purpose of the compression stage in a jet engine?

What is the primary purpose of the compression stage in a jet engine? I can understand the need for compression at high altitude, where the air is thin, but I suspect that it is not the primary reason for having a compression stage. Is there a reason why a jet engine won't work without compression even at low altitude? --173.49.11.120 (talk) 12:12, 18 August 2010 (UTC)[reply]

The Turbojet article is a great resource on this, and it has a section on the compressor. Simplistically, I think it's accurate to describe the jet engine as a continuous-flow combustion engine, such that there is no structural barrier to flow in either direction (fore or aft). As a result, the combustion chamber must be preceded by a high-pressure (compression) chamber to drive the combustion products rearward; otherwise, the jet wouldn't eject rearward and provide forward thrust. -- Scray (talk) 12:51, 18 August 2010 (UTC)[reply]

The compressoion stage pumps air into the engine to mix with fuel and burn, it also gives the air more energy by heating it up and putting it under greater preasure before being burnt with fuel. Without it the engine would not be able to funtcion at low speed, and would need help reaching a high enough speed so the high speed flow of air into the engine would compress the air itself. This is why ramjets and scramjets require another engine to bring them up to a supersonic speed before they can opperate. If you were to try to start a stationary ramjet or scramjet, you wouldn't get any thrust because they have no means of compressing the air, and the exaust gasses would simply exit out the front and the back of the engine providing no net thrust. In other words, the compressor pumps air into the engine that the engine needs to run and produce thrust out of the nozzle at the end of the engine, you can get rid of the compressor to make the engine simpler and opperate at higher temperatures, but then you need some other engine (conventional turbojet, turbofan, or rocket) to get that engine to the speed (several mach) that it needs for the air to compress itself with out the aid for a compressor.--74.67.89.61 (talk) 15:54, 18 August 2010 (UTC)[reply]

Life extension versus curing diseases one by one

I have found out just recently, to my amazement, that old age is not a cause of death (in humans), even beyond the age of 100^[27]. At advanced ages it becomes very probable that in some important place the blood will either become solid when it should remain liquid (thromboembolism, infarction) or stay liquid when it should turn solid (ruptured aneurysm, haemorrhage, etc.) i.e. the leading cause of death at advanced ages is "failure of the blood to be in the correct phase of matter", rather than "old age", and if that doesn't finish you off, cancer or an infection likely will. So, purely hypothetically of course, if we cure the diseases of old age and create "smart blood", and subsequently live to 160, is that "life extension"? Why do so many people think "life extension" is unethical but yet trying to treat, prevent, and cure the common diseases of old age one by one is not? 129.2.46.178 (talk) 13:21, 18 August 2010 (UTC)Nightvid[reply]

Well, dying from 'old age' is sort of an all-encompassing term, referring to a multitude of things in your body that can go wrong as a result of it. I think the answer of your question (a very good one, by the way) has to do with the way we perceive the concept of 'life extension'. If one does manufacture 'smart blood', that's going to cure a multitude of ailments. If one cures a single disease, many others will still die of other problems. However, if you cure a multitude, you start noticing the life expectancy go up. Life extension is more of a term used to describe extending one's life past the point of when one would have naturally died (for me it is). However, if you cure these diseases, you are extending the natural lifespan (without the support of other modern technologies). Tyrol5 [Talk] 13:48, 18 August 2010 (UTC)[reply]

There is a distinction between fighting senescence per se and fighting diseases; some of the more intriguing results in lifespan extension involve not just longer life and protection from disease, but also prolonged vigor.[28] Wnt (talk) 14:56, 18 August 2010 (UTC)[reply]

Weight of one phytoplankton cell

Yes, I know that this is impossible to determine because it's so small and there are about 5000 species, but I don't need a precise figure. Basically I've followed up my previous question with a bit more research, and I know the scale of plankton generation we were talking about is massively infeasible, but to prove it I need to know roughly how much the stuff weighs. Even if its only a really rough figure, or even just an order of magnitude, that would be enough for my purposes, because it's so infeasible to do this that even a massive exaggeration of their weight would still make it look impractical to generate that much plankton. Anyone know a figure that would help me?

Thanks! Dan Hartas (talk) 13:27, 18 August 2010 (UTC)[reply]

I would imagine that only one weighs far less than one microgram (e.g. really, really light). I'm afraid I can't give you a much more definite answer than that. Tyrol5 [Talk] 13:35, 18 August 2010 (UTC)[reply]

Heh yeah, "really, really light" is about all I know as well lol. Dan Hartas (talk) 13:52, 18 August 2010 (UTC)[reply]

Well, the problem you encounter as you reach these low figures is that the numbers keep getting smaller and smaller indefinitely (in essence, you never hit zero by counting back). Tyrol5 [Talk] 14:08, 18 August 2010 (UTC)[reply]

Obviously the answer is "0", just as the answer to the question "what is the thickness of a piece of paper?" is "0". A piece of paper is physically two-dimensional, it doesn't have thickness, and a phytoplankton cell is physically zero-dimensional, it doesn't have depth, breadth, height, or weight. (Unlike the other zero-dimensional object, the black hole, which obviously does have weight). Hope this helps. 92.230.233.158 (talk) 13:42, 18 August 2010 (UTC)[reply]

That's a ridiculous answer. A piece of paper is obviously a three dimensional object. Please don't answer questions you don't have the first clue about. Matt Deres (talk) 14:26, 18 August 2010 (UTC)[reply]

I'm glad you noticed. The obvious is not always true, however, and string physicists would say that the paper is much more likely to be 11-dimensional. If it is 11-dimensional, the sum of those two digits is 2 (as I said originally), but there is no obvious way to get from 11 to 3. So if either of us is in some sense right, it would be me. Cheers, 92.230.66.177 (talk) 18:53, 18 August 2010 (UTC)[reply]

To estimate the weight of a phytoplankton cell, have a look at our articles on the different species of phytoplankton. Many of these articles include approximate sizes of these organisms. Using the estimated sizes, calculate a rough volume (note that 1 cubic micrometer is equal to 1 femtoliter), and figure that the density of of these organisms is probably within shouting distance of the density of water (1-2 picograms per femtoliter). Since the size of phytoplankton varies across at least two or three orders of magnitude – depending on species – you're only going to get a very rough estimate anyway.

That being said, for your study, what you're probably more interested in is not the mass of an individual cell, but rather the mass density of phytoplankton which can be cultivated in a cubic meter of seawater. (More specifically, how much carbon is bound within the phytoplankton one can culture in a cubic meter of seawater.) The number of individual cells is virtually irrelevant to the sequestration; one cell gives rise to a billion billion daughter cells after just sixty doubling periods, so once the culture is up and running, maintaining the numbers shouldn't be an issue. TenOfAllTrades(talk) 14:37, 18 August 2010 (UTC)[reply]

Using TenOfAllTrades' method for Chlamydomonas reinhardtii gives you a wet weight of 1 nanogram, having a stab in the dark, I'd guess the dry weight would be around 1% of the wet weight - 0.01 nanograms. Smartse (talk) 16:12, 18 August 2010 (UTC)[reply]

Even in a good source [29] the wet:dry weight ratio seems remarkably uncertain (10% or 20% by assumption) but I don't know of any living thing that is 99% water. Also see "Net-plankton biomass in the Manazuru Harbor varied from 4.1 to 410 mg m–3 in dry weight; from 2.0 to 200 mg m–3 in ash-free dry weight; from 0.98 to 78 mg m–3 in organic carbon (Fig. 1)." [30] (These are just top two Google hits; serious research may find better data) Also note that one report claims we are making negative progress on your idea.[31] Wnt (talk) 16:24, 18 August 2010 (UTC)[reply]

Crowded cell environment anyone? I am pretty sure that water does not make up more than 90% of a cell by wt. It's probably even less. John Riemann Soong (talk) 21:22, 18 August 2010 (UTC)[reply]

Another issue: apparently picoplankton and nanoplankton pass right through plankton nets, and only microplankton are usually caught; but it is the former two that make up most of the biomass.[32] Depending on your situation you may care about the total or just the larger cells. Wnt (talk) 16:31, 18 August 2010 (UTC)[reply]

Well let's use more feasible units you could use under a microscope. The issue of a mass of a cell is important, when you're say trying to assay one cell culture and differentiate it from another. John Riemann Soong (talk) 19:23, 18 August 2010 (UTC)[reply]

Adult male cat being breastfed by another cat

I've seen an adult male cat being breastfed by a cat whose kittens had just stopped suckling. The two did not know each prior to the breastfeeding and that did not occur only once. The tomcat was certainly adult; he was larger than the female who was breastfeeding him. This lasted for several days, until the tomcat disappeared. I'd like to know:

What made the cat breastfeed another adult cat?
What made an adult cat suckle another cat?
How (un)common is this behaviour? The Spy Who Came in from the Cold (talk) 17:25, 18 August 2010 (UTC)[reply]

Maybe they had sex just after that. I have seen this behavior in horses. Sometimes just before the male starts fucking he causally licks the tits of the mare (though there is no milk there). And of course we (human) do it too. Jon Ascton (talk) 20:23, 18 August 2010 (UTC)[reply]

They did not mate. But thanks for not helping. The Spy Who Came in from the Cold (talk) 22:32, 18 August 2010 (UTC)[reply]

Car mirror -- "closer than they appear"

Why would the passenger side mirror show objects farther than they actually are -- isn't it just a regular mirror? DRosenbach ^{(Talk | Contribs)} 19:45, 18 August 2010 (UTC)[reply]

As curved mirror#Uses notes "The passenger-side mirror on a car is typically a convex mirror. In some countries, these are labeled with the safety warning "Objects in mirror are closer than they appear", to warn the driver of the convex mirror's distorting effects on distance perception." This paper is very relevant. -- Finlay McWalter ☻ Talk 19:51, 18 August 2010 (UTC)[reply]

but aren't all objects closer, since the ray from the object describes two sides of a triangle (object to mirror, mirror to your eye) where the direct view from your eye would be the third side of the same triangle? As long as the lengths of two sides of a triangle have to add up to more than the length of the third side, objects in mirror will be closer than they appear. 92.230.66.177 (talk) 20:05, 18 August 2010 (UTC)[reply]

The label is imperfect. It should be interpreted, "Objects are closer than they would appear if viewed through a flat mirror." The purpose is simply to remind drivers that the curved mirror has affected depth-perception differently than a flat mirror would. Nimur (talk) 20:10, 18 August 2010 (UTC)[reply]

I think you mean, "Objects are closer than they would be if they were seen in a flat mirror and appeared the same size." Which I think we can agree is not a very practical wording. --Anonymous, 21:18 UTC, August 18, 2010.

In other words, the driver, when he sees through back-mirror is under illusion that vehicle behind is quite far away, but really it is not as far away as it seems Jon Ascton (talk) 20:18, 18 August 2010 (UTC)[reply]

The reason why objects are made to look further away is so that you can see more of them within the narrow field of view provided by the mirror. It's just like a microscope, which lets you see an object very close, but only a tiny portion of it - just in reverse. Wnt (talk) 20:27, 18 August 2010 (UTC)[reply]

How a 3-year-old might participate in sharing his "knowledge" on Wikipedia: Deep Sea Tube Worms

I'm writing on behalf of my 3-year-old son. Somehow I got him all excited about the fact that wikipedia is an encyclopedia to which everyone on the planet can contribute. He kinda got the wrong idea. So, he loves to review the article on Giant Tube Worms (http://en.wikipedia.org/wiki/Giant_tube_worms) and wants to contribute this bit of fiction. Obviously, there's not really a place for that, so I guess our question is: are there any discussion pages on Wikipedia where people can have casual discussion on a topic? (we already think the answer is "no" after listening to "what Wikipedia is not," but I don't want to totally discourage him from participating in the future in a genuine way, so I'm wondering if there might be a way to validate his interest in participating, not just reading, but also to not just create junk. Maybe there's a kids' website along these lines that somebody knows about and can direct us to?!) Anyway, here's his bit of story: 'After deep sea tube worms disappear, the other animals come back and don't see the deep sea tube worms and think, "Huh, the deep sea tube worms aren't here." They aren't there!' --24.22.93.88 (talk) 23:10, 18 August 2010 (UTC)[reply]