Wikipedia:Reference desk/Archives/Science/2012 October 23

= October 23 =

Skunk-epoxy smell?
After using epoxy glue, I put the unused residue in a garbage can. Returning home hours later, I thought I smelled fresh skunk odor; then realized I was smelling the epoxy.

Is there a chemical similarity that would explain this or is it just a peculiarity of my nose? Thanks, Wanderer57 (talk) 02:32, 23 October 2012 (UTC)


 * Common chemicals that are easy to abuse as inhalants, such as some glues, often have Denatonium added. It is a bitterant, designed to make a product taste or smell unpleasant. I've never noticed a skunk smell from a product with a bitterant, but perhaps there are other bitterants that develop that smell. According to our article on skunks, the scent is pretty complicated - perhaps you're noticing something in the epoxy that is close to one of the components of skunk spray, and without more context skunk became the closest match. 209.131.76.183 (talk) 14:00, 23 October 2012 (UTC)


 * Also note that there is considerable variability in how people perceive smells. Here are two differences:


 * 1) Different people can detect different smells, with the odor asparagus produces in the urine being one example. Some people smell it, some don't.  In your case, perhaps you are able to smell a common skunk/epoxy component, while others can not.


 * 2) How our brain distinguishes and categorizes smells is different. So, some people might think that two similar chemical compounds smell the same, while other people do not. StuRat (talk) 14:10, 23 October 2012 (UTC)

Growth over a sliver
First and most important: this is NOT a medical question! So, here goes. A few months ago while unloading some wood from my truck, I go a sliver in my finger. I was able to pull most of it out but some remained and I was unable to get it all out. So, I just kept the area clean and didn't bother getting medical attention since it wasn't bothering me and there was no infection. So, at present, where the sliver remained it appears that my body has grown around the sliver and there is now something like a callous there. It is not bothering me nor does it impair any functioning but I am wondering about what happened from a biological perspective. What is the growth around the sliver? 99.250.103.117 (talk) 04:50, 23 October 2012 (UTC)


 * There are two possibilities:


 * 1) Scar tissue, which is white and hairless.


 * 2) Normal tissue, which looks, well, normal.


 * I got a splinter some 30 years ago, which was a piece of stained wood. I got out most of it, but the chunk buried deep under the skin remained there.  Normal skin grew over it, and, in time, the wood dissolved, leaving only the stain.  So, I gave myself a tattoo the hard way (not that the normal way is particularly easy). StuRat (talk) 05:05, 23 October 2012 (UTC)


 * There are others too I think? Hyperkeratosis? Callus? --BozMo talk 08:54, 23 October 2012 (UTC)

I am going to go with the scar tissue option! Thanks. 99.250.103.117 (talk) 19:30, 23 October 2012 (UTC)

Launching atomic weapons
Can atomic ballistic missile or group of them be launched by whatever unit is at charge? If they need a password from the president, then they can be disable by just attacking him, but otherwise, how to avoid a mad commander from launching them? Comploose (talk) 11:56, 23 October 2012 (UTC)
 * You may find the two man rule article worth reading. Richard Avery (talk) 12:10, 23 October 2012 (UTC)


 * While not cases of launching via the local commander, see also the cases of Vasili Arkhipov (who, as second-in-command, persuaded his CO not to launch a nuclear torpedo during the Cuban Missile Crisis), Stanislav Petrov (who correctly diagnosed a false alarm rather than passing a report of an American nuclear strike up his chain of command), and Dead Hand (a possibly-automatic Russian nuclear retaliatory system which may remain operational). There is also the case of Harold Hering, who was discharged from the US Air Force after asking, "How can I know that an order I receive to launch my missiles came from a sane president?" &mdash; Lomn 13:20, 23 October 2012 (UTC)


 * But, what if the Russian had attacked the US and destroyed the congress and White House? Would a nuclear submarine with a two man rule be able to decide on their own to retaliate? My knowledge is entirely derived from Hollywood films in this matter. I suppose they are not reliable sources, even if the question provides grounds for a thriller.  Comploose (talk) 13:23, 23 October 2012 (UTC)


 * Modern nuclear weapons in the US arsenal are protected by Permissive Action Links. You need authentication codes to activate the warheads; if you don't have the codes, the nukes won't work. These are transmitted only on order from the President or someone else in the line of succession (including the designated survivor in extreme circumstances). The codes (the so-called nuclear football) are kept near the President at all times. There are at least two other "footballs" in case one is destroyed somehow. I suspect there are fallback plans for all footballs being destroyed or inactive, but they likely do not involve allowing field commanders to make those decisions. There have been, in the past, procedures for "predelegation" of nuclear authority, where the President says, "I give you, the field commander, the authority to do this if you need to or if you think everyone over here is dead." I've no clue if those are still on the books but I wouldn't be super surprised if they were available in some form.
 * What really prevents rogue commanders a la Strangelove is a fairly intense system of surveillance, psychological profiling, and lots of overlapping authority. You can't get within 1000 feet of a live nuclear weapon without them knowing a lot about your life, including your bank records, and your current mental and physical health. There is no doctor-patient privacy in the nuclear triad. I've met at least one nuclear missile base commander over the years, and they are a tightly-wound, carefully-chosen bunch. (This in no way guarantees that everything is always functioning correctly, of course. There have been enough errors and accidents — even very recent ones — to make one quite disturbed. It only takes one big one for a lot of people to die...) --Mr.98 (talk) 13:48, 23 October 2012 (UTC)


 * In Britain we have a system of Letters of last resort. These are letters written by the Prime Minister immediately after taking office, and describe actions which may be taken by nuclear submarine captains in the event of destruction of British society (or, at least, the Prime Minister and another designated person who is authorised to take over from the PM in the event of his death). The contents of the letters are highly secret, but it is believed that they lay out a number of options to the captain, including turning the submarine over to US command, heading for Australia, or launching a nuclear missile. The circumstances under which a captain is authorised to open the letter are also secret, although it's believed that one criteria is being unable to receive Radio 4's Today program for a specified number of consecutive days - the theory being that if John Humphrys has gone off the air then British society has obviously come crashing down. If this seems a little amateurish, consider also that, in the 60s, with the Cold War in full swing, the Prime Minister wanted a radio fitted to his car in order to keep him in touch with GCHQ should it become necessary for him to authorise military action whilst on the road. It was decided that this would be too expensive, and so instead they agreed to use the AA's radio network. In an emergency, the AA would be sent a coded message, and would call on one of their patrolmen to flag down the prime-ministerial car. The PM would then get himself to the nearest public phone box and call central command. A supply of small change was kept in the car for this purpose. - Cucumber Mike (talk) 13:55, 23 October 2012 (UTC)


 * It's possible that American submarines have something similar, though I've never heard of it being the case. Our article on PALs though says that the UK doesn't use them, so it's not like that secret letter has to contain authorization codes. There are no UK authorization codes. Kind of disturbing. --Mr.98 (talk) 14:10, 23 October 2012 (UTC)
 * Although, at least in the early days, the code for the Nuclear football was 0000, hardly the most secure code in the world. The PAL article says that the UK used to have physical locks on their airborne nuclear missiles derived from bicycle locks. Nowadays, though, I think I'm right in saying that the only nuclear weapons we control ourselves (as opposed to American missiles that may or may not be based on British soil) are the submarine-based Trident missiles. These do have codes, at least according to this Daily Mail article. - Cucumber Mike (talk) 14:32, 23 October 2012 (UTC)
 * Aha, here we go. Nuclear weapons and the United Kingdom: "Currently, British Trident commanders are able to launch their missiles without authorisation, whereas their American colleagues cannot." See also, in the same article, the procedure under which a submarine commander may appeal to the Queen should he mistrust the orders he is given - presumably this option isn't open to their American counterparts. - Cucumber Mike (talk) 15:00, 23 October 2012 (UTC)

Cancer: cause and lack of cause
If a smoker gets lungs cancer people will say it's because he smoked. In cases where it's not evident, like children, people say that it's something that sometimes happen, in the sense that it's spontaneous there is no concrete explanation. But couldn't the first case also be spontaneous sometimes? Comploose (talk) 12:04, 23 October 2012 (UTC)
 * Yes, it could possibly be a 'spontaneous' cancer in a smoker, by spontaneous I assume you mean causes other than tobacco smoke. The real difficulty is how would we know whether the cancer is smoke related or caused by the several other causes this site explains, ranging from secondhand smoke to radon within the home. Richard Avery (talk) 12:25, 23 October 2012 (UTC)


 * It is important to recognise the difference between root causes and triggers. Smoking is never a root cause of cancer, it is a trigger or possibly an accelerant.  The root cause in lung cancer and almost all forms of cancer is genetic faults.  An analogy is the failure of a lawnmower engine with dirt in the fuel.  The dirt is the trigger of failure to run when it gets in the carburettor.  But what is the root cause?  If the owner correctly maintained the lawnmower, replacing any parts as appropriate, taking care with re-fueling, using a fuel strainer when re-fueling, the dirt wouldn't get in.  However, if there is no dirt, the mower would run regardless.  Hence dirt is the trigger, and not using a fuel strainer the root cause.  Once you have cancer, it is possible to identify the root cause, and the most probable trigger, but with lung cancer they usually don't bother as the treatment will be the same in any case.  Wickwack 124.178.178.65 (talk) 13:17, 23 October 2012 (UTC)


 * Cancer is a hard thing to pin down causally in individuals. Its onset is fundamentally probabilistic — you have many trillion cells, and whether one of them becomes cancerous in a dangerous way that the body doesn't detect and fix is largely a matter of chance. Your cancer risk — the chance of that happening — is definitely affected by both environmental sources (smoking, radioactivity, chemicals, etc.) as well as genetics (lingering bad codes in your genes). In an individual, you can never really tell what caused a given cancer — there are so many possible sources in modern life, including some that you can't predict for at all (e.g. a high energy cosmic ray happens to strike the wrong cell in the wrong place). What you can say is, over a given population, X number who are exposed to a particular environmental source (e.g. smoking) will develop cancers. In this way you can quantify these cancer risks and say things like, "smoking increases your cancer risk by X% over the baseline," and "radon gas in your basement increases your cancer risk by another X%" and so on. There are also cancers which are associated, statistically, with particular environmental exposures, which makes a more plausible argument — lung cancer for smoking, for example, but also bone and stomach cancers for certain types of radiation exposures, and so on. They aren't, though, complete smoking guns; it's still a statistical, population-based argument that is being collapsed to a "what is most likely" the cause of a specific cancer in a specific individual.
 * This isn't to say that the cancers don't have causes. All cancers have "causes" — we just don't have any way of knowing what they are, except probabilistically. The most spontaneous-looking "cause" is genetics, though ironically that's probably the easiest one to pin down (or will be, in the near future), since we can actually screen for many known cancer genes. The truly "spontaneous" ones, like exposure to cosmic rays or natural radioactivity, are very hard to isolate from the other many possible environmental causes. (Note that even more complicating is that these risk factors can interact; radon gas exposure, by itself, does not raise your risk level very much. If you smoke cigarettes around radon gas, though, your risk factor shoots up, because the radon daughter decay products hitch-hike on the cigarette byproducts and do a lot more damage than either the smoking or the radon would do on its own.)
 * Wrapping one's head around probabilistic risks is not intuitive and unsurprisingly a lot of people either revert to simple statements like "X causes cancer," which can get misleading because we all know people who are exceptions to that rule and this in turn causes a lot of people to reject these statements ("my grandmother smoked until she was 89 and she was fine, so how bad could it be?"). This is a major difficulty in the public health and risk communication worlds.--Mr.98 (talk) 14:04, 23 October 2012 (UTC)


 * Mr 98 is dead right about it not being intuitive and it being difficult to understand, but appears to have missed the point about root causes vs triggers. Neither smoking nor radon gas nor cosmic rays are root causes.  They are triggers.  Consider:  Can a person who has no genetic faults get cancer, even if they smoke, inhale reasonable (& even some unreasonable) quantities of radon gas, or have a natural cosmic ray inundation get cancer?  The answer is no.  Can a person who has a sufficient range of genetic faults, but no exposure to smoke, radon, or cosmic rays get cancer?  The answer is yes.  If a person, who has developed cancer, has that cancer eliminated by medical treatment, and ceases exposure to trigger get cancer again?  The answer is yes, and it occurs with significant probability.  Note that noboby gets cancer with only a single bad cell and nobody gets cancer with only a single cancer-relevant genetic defect.  To get cancer you must have a combination of genetic defects - a defect that allows the progeny of stem cells to keep on dividing, a defect that prevents appropriate adjacent cell-mediated cell death, and at least one genetic defect affecting the immume system response to tumours.  This is why it has taken quite a while to figure the casues of cancer out.  It used to be thought that ionising radiation causes cancer at rates that are a function of exposure, with the natural exposure responsible for the natural rate at which cancer occurs.  In fact, a genetically sound person will not ever get cancer (certain unusual forms may be exceptions) unless subjected to extreme exposure.  Trouble is, probably 25% of the population has some genetic defects.  Cancer has only seemed to be probabilistic because we haven't understood it until very recently.
 * The fact that root causes vs triggers has not been understood by public health educators and communicated to the public is why you get "My grandmother smoked like a chimney and lived to 89, so it can't be smoking". However, if the public becaomes too scared to smoke, that's a good thing in multiple ways.  Wickwack 124.178.178.65 (talk) 15:18, 23 October 2012 (UTC)


 * Wickwack, what you say is at least scientifically unsound, but I would rather tend to call it incorrect. There is no such thing as a "genetic defect". Every human has a genome consisting of thousands of different alleles (and a "healthy genome" doesn't make sense as a scientific concept), and every second, mutations happen in some cells of the body. If you talk about cancer, there is no such thing as "a person's genome", it's all a boiling ocean of mutations and selection/counterselection inside of the body. If you irradiate a tissue (or expose it to certain chemicals), you increase its mutation rate, which can increase the probability that exactly the right combinations of mutations meet inside a single cell to become the phenomenon we call cancer. While your assessment of the needed mutations is a nice list, it is oversimplified, as is the linear development of tumors. There are very many pre-malignant lesions in each healthy human, at every moment. Your distinction of "root causes" and "triggers" is artificial. Cancer works the way it works because of the physical laws that govern our cells. It's like answering the (philosophical) question "what came first, the hen or the egg?". Cancer is a logical consequence of how our body and genome work, in every one of us. Btw: The reason why people that got a cancer treatment are at a higher risk for "getting cancer again" is not the genome they received from their parents (for most people without defects in DNA repair), but is a consequence of "cancer cells" left over after treatment, that linger on and sometimes grow out again. Even the treatment can't negate the stochastical nature of cancer, so you normally can't kill every mutated cell (or the pre-malignant cell clones that might still be around, somewhere).
 * So, to summarize: Cancer might be a hard topic, but please don't simplify to such a degree that you are making claims that are not backed up by reality (where do the 25% even come from?!?). --TheMaster17 (talk) 16:03, 23 October 2012 (UTC)


 * I think that this "root causes" and "triggers" issue may muddy the waters. The "root cause" of cancer, if you will, is that humans are designed wrong - there are events that can occur with low frequency in anyone to cause the disease; given long enough they will.  But the fact that some circumstances increase this risk doesn't seem to make them less important, to me.
 * The biological concepts are that there are tumor initiators and tumor promoters, which work a bit differently. A tumor initiator is something (UV, radiation, chemicals) that directly increases mutation - i.e. a mutagen.  (As an aside, I would think "epigenetic tumor initiators" would be possible, but the phrase is unknown to Google, and I didn't find anything on it in a very quick search.  DNA demethylation is supposed to contribute, but actually zebularine (a DNMT inhibitor) fails to deliver and actually protected against tumors in one test.   Nonetheless the existence of normal mice produced from teratocarcinoma cells proves that, in theory, a tumor can form by more or less entirely epigenetic mechanisms, and I didn't look long or hard enough to know that a proper search wouldn't find something)  Anyway, a tumor promoter works to increase the propagation of cells with the initial mutation, so that they can eventually accumulate a bunch of mutations that lets them grow to large size and ignore signals to die, i.e. become fully transformed.  (Sorry - I cannot believe what a sorry state these three articles on cancer are in, considering the importance of the concepts) Wnt (talk) 17:49, 23 October 2012 (UTC)
 * Yes, I (Wickwack) presented a very simplified view. I was well aware of that when I posted.  To describe cancer accurately would probably take millions of words.  And not be entirely possible, because not all the details are yet known.  I also chose to use lay terms such as "adjacent cell-mediated cell death" rather than the correct term cell mediated apoptosis (programmed cell death). Wnt and TheMaster are not wrong entirely, but are presenting a picture that needs revising in light of facts uncovered by research only recently.  One should always be carefull not to keep on repeating an older picture that is not wrong exactly, but has been revised by recent discoveries. It's a bit like our undersanding of the atom. Early on scientists developed a model comprising a nuecleus surrounded by orbiting particle electrons in "shells".  It's now known that this isn't right, but it still does explain certain things in physics and chemistry just as well as it always did.
 * To cite a cancer example to explain the root cause/trigger model, it was discovered about 18 years ago that most women who develop the most common forms of breast cancer have a certain genetic defect, which they named BCRA-1, BReast CAncer gene 1, because they were breast cancer reseasrcher investigating breast cancer. It was later shown that this defect, which is inherited from a parent, not a spontaneous mutation, compromises DNA repair, and it is involved in many types of cancer, not just breast cancer.  So the name is misleading, but it's the name that is in use.  BCRA-1 is a root cause, because if a woman, or man, doesn't have it, their chances of getting breast and certain other types of cancer is signifcantly reduced.  It is not reduced to zero, not merely because of a "boiling ocean of mutations and selection/counterselection inside of the body", but because there are other root cause genetic defects possible.
 * Yes, the body does have DNA damage and mutations happening all the time. Yes, the design isn't perfect - in a sense we are designed wrong.  But, as we are an evolved system, our ancestors have long evolved built-in means of recognising and dealing with potential and actual cancer.  It's when these evolved mechanisms themselves acquire inheritable defects that cancer becomes the huge problem that it is.  Back to BCRA-1 (and the subsequently discovered BCRA-2), it was very sad that when a test become available for this genetic defect that some women had the test, tested positive, and had their breasts pre-emptively removed.  Why?  If the only genetic defects you have are BCRA-1 and BCRA-2, you can't get breast cancer.  And if you DO have BCRA-1 and BCRA-2 and a different set of other gene defects, you most likely will not get breast cancer, but you have a higher probability of getting some other sort of cancer somewhere else in the body (which my BCRA-1 positive wife in fact did).
 * Some inherited factors increase cancer susceptability but confer an advantage in other respects and can even be essential to life. This does not invalidate the root cause & trigger model. You can have an inherited propensity to overweight - this will make it easier for breast cancer to grow, but it is not the root cause.  In a nomadic life the ability to put on weight when food is plenty may be an advantage.
 * Far from muddying the waters, looking at it from a root cause & trigger angle improves understanding, and explains why for example that although smoking and lung cancer is strongly linked, only some people who smoke get lung cancer.
 * Wickwack 124.178.55.56 (talk) 01:47, 24 October 2012 (UTC)


 * Wickwack, you are doing it again. BRCA-1 and BRCA-2 are not "defects" that you have or don't have, they are genes that every human on the planet has two copies of. Again, I can guess what you are alluding to: There are certain variants of BRCA-1/2 (called alleles in genetics) that can raise the statistical risk for certain tumors (among them certain types of breast cancer). As it stands above, your statement is clearly wrong. Please, don't simplify concepts to such a degree that they become wrong. Also, talking about "design" in a biological context is very, very unscientific. There's nothing "wrong" with those people that develop cancer, and for sure there's nothing wrong with our genome. "Wrong" and "Right" don't exist as a biological concept. Organisms are the way they are because of evolution (which in itself is depending on the physical laws of our universe), no one designed them, and they are "perfect"(which is not a biological concept) in the sense that they out-competed their long gone ancestors and there's nothing better around. --TheMaster17 (talk) 09:09, 24 October 2012 (UTC)
 * Actually, the terms "wrong" and "design" were introduced by poster Wnt, not me. But he not wrong in using this terminology in teh sense that he was - he meant our "design" is not perfect because we do get cancer.  Can't argue with that, but it is not the most useful concept.  Wickwack 60.230.234.252 (talk) 11:32, 24 October 2012 (UTC)


 * Regarding The Master's statement "[th]e reason why people that got a cancer treatment are at a higher risk for "getting cancer again" ... is a consequence of "cancer cells" left over after treatment, that linger on and sometimes grow out again" is obviously true, and has been known for considerable time. But, again recent research, and experience of oncologists has shown that this is decidedly not the whole picture.  30 years ago, if you had got say, breast cancer (and was treated for it), then, years later, got cancer somewhere else, it would be assumed that it was a metastasis of the orginal cancer, and it didn't matter because the treatment was essentially the same (cut it out and use methrotrexate-style chemo) anyway.  20 years ago if you had got breast cancer in one breast (and was treated for it the usual way - lumpectomy or mastectomy, chemo, and radiotherapy) and years later had breast cancer in the other breast, it would be assumed that either it was a spread of the original cancer, or a similar type of cancer arising independently.  But the tools are available today (microscopic analysis, marker detection, etc) that can show which it is, either a) that yes it is a separate tumour of the same type, or (b) it is a tumour of a quite different type.  And the treatment will be adjusted accordingly.  30 years ago, if the first detected tumour was in(say) your brain, it would be assumed to be a brain tumour.  But with today's tools, it may be determined that it is in fact a secondary (and often what type of primary must be the case) - and they'll go looking for the primary, which is presumably still there somewhere (sometimes it has disappeared) as it was not treated, so they can treat it appropriately.  It is becomming clear that in quite a high percentage of cases, a second diagnosis of cancer is of a cancer quite unrelated (except thru a common genetic root cause) to the fist one diagnosed, i.e., is not something arising from cells left over after treatment of the first one.  Incidentally, DNA repair is not the only built in feature that the body has for protecting itself from cancer, as I mentioned above.  Wickwack 120.145.166.64 (talk) 03:30, 24 October 2012 (UTC)


 * I demand references for that statement. The most common case if you have a tumor relapse after treatment is a reoccurence of the same tumor (which, as you correctly state, is not hard to prove nowadays). There are some therapies that have some risk to induce a "new" secondary tumor by their own mutagenic effects, but those cases are becoming rarer and rarer (not more common as you seem to imply) because dosing is better than it was and those therapies are slowly replaced by better ones that don't have such strong mutagenic effects on non-tumor cells. --TheMaster17 (talk) 09:17, 24 October 2012 (UTC)
 * You did not read what I said. I did NOT say that treatment induced secondary tumours are more common now (neither did I say there has been an increase in treatment induced primary tumours) - I agree, refinement of treatment techniques (better radiotherapy machines and radiotherapy planning tools, better chemotherapy agents, and better adjuvant drugs) over the years has reduced such problems.  What I DID say, if you go back and look, is that it is now being found (whith new diagnostic tools and with oncological experience) that more than one primary tumour type in the same patient is quite common.  There's no reason to suugest they have become more common (except that longer lifespans increase the chances) - its a case of better tools bringing it to light.  The occurance of treatment induced tumours is a separate issue.  You implied that treatment induced cancers are always secondaries.  I assume that you did not mean to imply that.  In any case it is quite wrong.  For instance, it has been well established for 20 years that certain adjuvant drugs for breast cancer increase the risk of uterine cancer - not a secondary breast cancer showing up in the uterus, but a new primary of different type.  You might like to clarify which statement you want a reference for - I can then find one or more for you.  Wickwack 60.230.234.252 (talk) 12:49, 24 October 2012 (UTC)


 * I agree, I meant "primary tumor" after a relapse, not secondary, which should be clear from the context. I would be interested in a reference to the "more than one primary tumour type in the same patient is quite common"-claim. If you mean by "common" "a freak chance of less than one in a million", then I agree. But for everything else I would want references. And just to clarify: We are speaking about tumors, about full-grown cancer. I'm aware that every living human has probably several sub-clinical mutated cell masses in his body, but they are not ordinarily regarded as "cancer", because they don't do any harm and are controlled by the immune system and cell intrinsic safety measures. Seeing a patient with two diffenrent cancer types at once is very, very, very rare according to medical literature; in fact so rare that it is hard to give reliable numbers for the chance, because most of these patients have pre-established conditions (defects in their DNA-repair, for example) that make the occurence of multiple tumors much more likely. --TheMaster17 (talk) 14:36, 24 October 2012 (UTC)
 * By "common", I certainly do NOT mean a one-in-a million thing. It's early days yet, but as until recently not only were the tools not available, the treatment would not have changed.  Doctors are taught to not order a test if it won't change treatment.  However we have now entered an era where the result will mean tayloring the treatment to suit.  The incidence of tumours of differing type seems to occur in about 1 in 10 cases involving multiple tumours of common types, but it could be signifanctly less; it could be more.  I will provide refrences when I get time.  Do you have references to support your claim that muliple types in teh one patient is rare?
 * I agree that it is not useful to call "cancer" some wonky cell somewhere in the body. But your term "full blown" is no good either - do you mean diagnosed malignant?  Or metastased all over the place and about to finish the patient off?  By "cancer", "tumour", I meant a tumour that is detectable, either by the patient noticing a lump or symptom, or by imaging and pathology methods now commonly in use in Western countries.  As you may know, cancer is discussed by medical people in terms of staging.  Stage 1 is a tumour in situ and not detectable in lymph nodes, Stage 2 is detectable in lymph nodes, up to Stage 5 - make peace with Aunt Frizzie while you still can.  Generally tumours should these days in Western conutries be diagnosed at Stage 1 or perhaps Stage 2 and are assumed that they will progress to Stage 5 if treatment is not done.  So, in the above posts, I effectively meant Stage 1.
 * Wickwack 60.230.234.252 (talk) 15:43, 24 October 2012 (UTC)


 * The root cause and trigger way of looking at cancer is of benefit because it doesn't just help explain why you shouldn't smoke (smoking being a trigger) even though we all know multiple people who have smoked all their adult lives without getting lung cancer, it explains why, if you have a parent that developed lung cancer, you definitely shouldn't smoke, even if that parent never smoked (you may have inherited some duff genes - the root cause, and the parent had a different trigger). Root cause analysis and its terminology originates in engineering.  It is not (yet) well established in the medical field becasue it has not in the past seemed usefull.  It does not mean taking it to rediculous and not usefull lengths.  One would not usefully suggest that the root cause of cancer is our evolutionary path - as Wnt pointed out.  An analogy is the motor car.  Cars sometimes breakdown, but very seldom if they are maintained and serviced according to manufacturer's guidelines.  You could say the root cause of a breakdown is the evolution/refinement path of vehicle design since manufacturing started.  But that would not be terribly usefull.  If however, you investigated a series of breakdowns and found that a dealer was not servicing customer's cars correctly - that would be a root cause, and very useful action could be taken on that basis.  Noting that some customers had more breakdowns because they drove their cars hard could also be usefull, but not as usefull as finding the root cause.  — Preceding unsigned comment added by 60.230.234.252 (talk) 13:19, 24 October 2012 (UTC)


 * What exactly does "is not (yet) well established in the medical field" mean? The more I read this, I have the impression you are making this "root cause" thing concerning cancer up. I never heard about such a distinction, and in my opinion it is not even logical. A cause is a cause. I can't see any fundamental difference between those things you call "trigger" and those things you call "root cause", perhaps only that you believe your triggers are more immediate in effect, while "root causes" are somehow inherent in the person/thing itself. This distinction is not really useful or helpful to understand cancer. And what Wnt pointed out was very much correct: One of the causes of cancer is on a fundamental level the way our body and cells are organised, which is rooted in our evolutionary path. Creatures with different evolutionary pathes get different cancers, and some can't even get cancer at all (think about single celled liveforms). The analogy with the car is wrong at so many levels, I don't even know where to start. Again, please don't simplify things till they are wrong. I suggest that if you want to discuss this further, let's move to my talk page (as you use dynamic IPs and are not logged in, your talk page wouldn't be that useful) to not clutter the reference desk any more. --TheMaster17 (talk) 14:51, 24 October 2012 (UTC)
 * Oils aint oils; Causes aint causes. I would have thought this obvious.  I'll try a different analogy:  It happens that I have a problem with nuts.  If I eat nuts, I'll cough a lot and make wheezing noises.  What is the cause of the wheezing and coughing?  You could say it is the nuts.  You could say it is just tough luck - what I ended up with after x many millions of years of evolution.  Or you could say the root cause is the particular gene variation I have - it's a gene variant (root cause) that makes me sensitive to nuts (the trigger).  I don't know if that gene has some advantage, as far as I know nobody does.  But it matters not.  At the moment it matters not much to me what terminology is used, but it might at some future time if they invent a suitable gene therapy.  And it's good to know that I can pass this root cause on to offspring.  The terminology suggests latent causes versus immediacy, but that is not the core concept.  Most triggers in cancer are not at all immediate in effect - smoking and asbestos fibres are obviously far from immediate, typically needing 40 years + to get to Stage 1 cancer.  However, most, but not all, root causes are inherited.  Wickwack 60.230.234.252 (talk) 16:02, 24 October 2012 (UTC)

Two-pack-a-day smokers are 28 times as likely to get lung cancer as the general population. So take your population of such smokers who have lung cancer, maybe 3.6% would have gotten lung cancer anyway. (Source: Weinberg's Biology of cancer). Someguy1221 (talk) 18:00, 23 October 2012 (UTC)
 * Have you correctly understood the reference? That figure (28 x ~ 30 x) is commonly quoted and is derived from comparing recent cancer rates with the reported rate before smoking became widespread.  But it is known that cancer was under-reported in earlier times, and there may be other modern era causes, such as increased lifespan and increased body weight.  About 10% of lung cancers diganosed occur in non-smokers (well, they said they were non-smokers anyway).  Wickwack 124.178.55.56 (talk) 02:05, 24 October 2012 (UTC)
 * The reference I used was a textbook which did not give the study's methodology. I'll have to check that then. Someguy1221 (talk) 09:20, 24 October 2012 (UTC)

Just to at least try to give a referenced answer to the OPs question: Our article cancer is quite good, and has an elaborate section about causes. --TheMaster17 (talk) 15:10, 24 October 2012 (UTC)


 * I think part of the controversy of this section is the classic false Nature versus nurture dichotomy: Is cancer "caused" by one's nature (genetics) or "caused" by one's nurture (environment). The answer, as with nearly every one of these false dichotomies, is that cancer is caused by the intersection of nature and nurture.  That is, it is usually not sufficient to have one and not the other: A person who has the correct genes to get a specific certain cancer may never get it if they are not exposed to the correct environmental triggers, while a person who smokes two packs a day for 30 years may never get lung cancer if they aren't predisposed to it.  It also isn't as simple as pure cause-and-effect: there's likely some dumb luck involved as well: it's a percentage and probability thing, not a "action and reaction" thing.  -- Jayron  32  18:36, 24 October 2012 (UTC)


 * I would like to add that there's (biologically) no difference between "having the right genes" and "having the right environmental conditions" (as Jayron alluded to with the false dichotomy). In the end, all that is important is that certain gene variants come together in the same cell. Whether some of them come from your parents (in the form of genes that you inherit) or from physical/chemical effects that changed the DNA of the cell after conception, doesn't matter from the tumor's perspective. It all boils down to stochastical chances for this to occur. Sure, if you bring half of the genetic changes in the DNA of your whole body with you from the start, the chances are surely higher to develop cancer, but it's still only a chance. On the other hand, even if we imagine that there might be humans that are highly resistant to cancer (because their parents gave them just the right mix of gene variants), nothing stops the first hundred cosmic rays that strike their body to change just the right pieces of DNA in just the right cells for a cancer to occur. It's just very, very unlikely. It might be that we can give better numbers to those chances in the future, but they would still only be chances on a population level. It's like a lottery: Although the chances to win are really slim, there are winners every week. --TheMaster17 (talk) 09:02, 25 October 2012 (UTC)

zodiac articles
I'm wondering what happened to the zodiac article dealing with different astrology signs it used to be Each sine had its own page, giving it a detailed description and interpretation. Now when you click on a month it just goes to a catch all page which doesn't explain much what happened to the individual pages?--Wrk678 (talk) 12:40, 23 October 2012 (UTC)


 * As an astronomical feature, each constellation has an article, i.e. Aries (constellation). I'm surprised that all the articles on the individual zodiac signs have been made into redirects. Perhaps ask WikiProject Astrology what's gone on there? LukeSurlt c 13:09, 23 October 2012 (UTC)


 * Hmm. Yesterday User:Dominus Vobisdu went and changed all the sign articles to redirects. I don't know if this was unilateral or followed a discussion. LukeSurlt c 13:13, 23 October 2012 (UTC)


 * The same user has, over the past few weeks, deleted or made substantial cuts to all of the Chinese zodiac signs, and if you go back further other astrology-related and similar articles.  → Michael J Ⓣ Ⓒ Ⓜ 14:16, 23 October 2012 (UTC)


 * If this is all unilateral, he should be reverted. Sure astrology isn't valid science, but it still merits substantial articles, due to it's cultural impact. StuRat (talk) 14:18, 23 October 2012 (UTC)


 * If there were anything approaching reliable sources which discussed the cultural impact of zodiacal signs, you'd have a point. As it stands, all there seems to be on the subject is vague and contradictory waffle from astrologers who clearly can't agree anything amongst themselves - and don't actually want to, as it would cut the market for further contradictory waffle. AndyTheGrump (talk) 14:26, 23 October 2012 (UTC)


 * You seem to be confusing the validity with the cultural impact. Finding reliable sources that show the cultural impact should be simple enough, say a poll of the percentage of people who believe in, and alter their behavior due to, their horoscopes.  I believe Nancy Reagan was one.  From our article: "...more controversy ensued when it was revealed in 1988 that she had consulted an astrologer to assist in planning the president's schedule after the 1981 assassination attempt on her husband. " StuRat (talk) 14:33, 23 October 2012 (UTC)


 * You seem to be confusing the cultural impact of astrology with the cultural impact of individual zodiacal signs. AndyTheGrump (talk) 14:33, 23 October 2012 (UTC)


 * As StuRat says, we should have articles on these as cultural phenomena. Even if they were crappy, having no articles to improve seems worse. Currently Wikipedia has no information on what pseudo-guff is associated with which sign. These things have a wide enough cultural footprint to be of encyclopaedic impact. LukeSurlt c 14:36, 23 October 2012 (UTC)


 * The astrologers can't agree on the pseudo-giff though - they all say different things. Which makes assessing the cultural impact of an individual sign rather difficult... AndyTheGrump (talk) 14:40, 23 October 2012 (UTC)


 * True, but even in difficult cases we still have articles. Generally speaking we can't just have 12 articles effectively deleted unilaterally, this sort of action requires a community discussion. LukeSurlt c 14:50, 23 October 2012 (UTC)


 * (EC) This discussion would best be held elsewhere. But anyway it seems to me that point of whether those articles should exist is largely moot. The content which was deleted seems to be the sort of stuff which should be covered in the redirect article and largely is. In the event of a dispute over the existence of the articles, the best way to handle that would be to find and add enough reliably sourced info to justify stand alone articles rather then argue a hypothetical of what could be in those articles. Remember the articles weren't deleted so all content remains in the history and you're free to reverse the redirect particularly if you add enough info to justify their being an article. Nil Einne (talk) 14:56, 23 October 2012 (UTC)


 * Wouldn't it be best to ask Dominus Vobisdu whether this was an unilateral deletion first? AndyTheGrump (talk) 14:57, 23 October 2012 (UTC)


 * I've slightly modified my response above but one key point was there from the start. As I said, there was no deletion. Therefrore such a question wouldn't make sense. Nil Einne (talk) 14:59, 23 October 2012 (UTC)


 * OK, I've restored them to how they were prior to redirection, and suggest we hold a centralised discussion on Talk:Astrological_sign. LukeSurlt c 15:14, 23 October 2012 (UTC)


 * We shouldn't dismiss astrology entirely without thinking about it. Sure, it's based on absurd theories, but suppose, say, the women in some village got a hankering for tea made with fresh veratrum flowers.  (Hippocrates was a great believer in the stuff, but I think he administered it all times of year)  Well, because of the critical periods of development, there might be one or two Zodiacal signs that specifically direct the birth of baby Cyclopes.  Who knows - it is possible that somewhat less obvious characteristics have, at certain times and places, followed a rough astrological calendar in this way. Wnt (talk) 18:56, 23 October 2012 (UTC)


 * I would recommend reading up on what astrology is before commenting about how you personally find it plausible. You would need to show evidence for such a correlation of personality on the time of year. You would then need to show that this correlation corresponds in some way to the astrology divisions in sun sign astrology (which actual astrologers regard as inaccurate). Then you would need to explain why astrologers have failed every test to work out personality greater than that explained by chance alone. Then you need to explain why astrologers all make statements which all disagree with each other in the tests themselves; there is no consistency. Then you need to explain why you think the apparent position of a planet on the Celestial sphere, at your time of birth say, has an effect on you. Then you would need to explain why the angles the planets make with respect to each other, from the arbitrary position, matters. Then you would need to explain how your belief about the origins of astrology is consistent with the historical evidence for it's origins, such as with it's "modern" origins with the works of Ptolemy etc. Then you would need to explain why this correlation means we still shouldn't dismiss what astrologers do since they have failed every controlled trial of their abilities. You have your work cut out for you. IRWolfie- (talk) 22:24, 23 October 2012 (UTC)

It seems I misread, you weren't talking about personality but Cyclopes? What are you talking about and why would that influence whether we dismiss astrology or not as a hypothesis about the universe? What on earth do cyclopes have to do with astrology? You've constructed an absurd example, without evidence and assert that this somehow makes a concept, which doesn't mention cyclopes plausible to you? Whether some old villagers committed a post hoc ergo propter hoc style logical fallacy says nothing about whether astrology is correct or not. By the same logic maybe the anti-vaxers are right because someone got a jab and then got hit by a bus. IRWolfie- (talk) 22:39, 23 October 2012 (UTC)
 * There's some cases where the time of year that you are born can affect you, for example if your school system has a fixed date cut-off being older than most of your classmates throughout school is an advantage. Also I've read that late-stage foetuses of mothers who observe Ramadan, especially where the days are long, can be at a developmental disadvantage. These can be explained by "terrestrial" phenomena however and not any action of the stars. LukeSurlt c 00:07, 24 October 2012 (UTC)
 * (I lifted those examples from Superfreakonomics by the way) --LukeSurlt c 00:11, 24 October 2012 (UTC)
 * In case I was unclear, I was not suggesting a belief in the system in its entirety - since so far as I understand no two astrologers really agree on everything, to suggest that seems excessive. The question rather is whether someone who didn't know any better, armed with a notion that astrology works, who makes ad hoc attempts to apply it to the local situation based on trial and error, might adapt the framework to make predictions that are correct more often than chance.  And the answer still is probably not... but not impossible.
 * If I had to take a wild guess at something more plausible than Cyclopes, I'd suggest phytoestrogen mediated effects ... but those themselves aren't so clear to me. See  for the kind of thing I'm thinking of.
 * Keep in mind always that when we speak of the historical times when astrology evolved, life was very different. People couldn't buy raspberries any time of the year!  Although some crops had the valuable ability to be stored for long periods, there were many things which were available only at one specific time.  And different foods were eaten, sometimes by necessity, or at unlucky times nothing at all.  So I'm thinking that the variation of pregnancies from different times of year would have been much greater than it is today. Wnt (talk) 06:43, 24 October 2012 (UTC)
 * So what if some coincidence happened? Why would that prevent someone rejecting astrology? This is the same as saying that "maybe the homeopaths are right because sometimes people are dehydrated and they took water; and maybe by a system of testing they adapted their framework". So what? Their actual conclusions are all wrong; we would still reject homeopath because it doesn't work, whether or not some guy was dehydrated in its history. IRWolfie- (talk) 20:19, 25 October 2012 (UTC)


 * One article for this nonsense is more than sufficient. The individual signs could be redirects to the one article. ←Baseball Bugs What's up, Doc? carrots→ 03:03, 24 October 2012 (UTC)


 * Right you are! And one article should be more than sufficient for all this nonsense that is called religion, too. 78.43.28.199 (talk) 15:16, 24 October 2012 (UTC)

Also, in the Individual astrology sign articles they used to have a detailed description of the sign and its characteristics, compatibility ect in fact if gave the best overview of any site on the web that I could find, Why has this been deleted? A good example is the Taurus article, if you go back about 6 months you can see what I'm talking about. example: http://en.wikipedia.org/w/index.php?title=Taurus_(astrology)&diff=504352086&oldid=504350494 --Wrk678 (talk) 06:19, 24 October 2012 (UTC)
 * It has been deleted because it is not encyclopedic. It uses as its sources, articles like "Deborah Houlding, ‘Taurus the Bull'. The Mountain Astrologer, issue #142". I don't think a magazine about astrology really counts as a "reliable source".. The thing is, there is NO reliable source when it comes to making up clap trap, it's ALL clap trap. Compare it to the article in Britannica.. Now I'm not suggesting wikipedia necessarily should be held up to Britannica, but I think they have the right idea. If someone wants to learn about the superstitions they can learn them from a website that peddles in those superstitions.. Vespine (talk) 21:51, 24 October 2012 (UTC)
 * The problem isn't so much that it is claptrap - the problem is that it is inconsistent claptrap, Every astrology source says something different, as is made clear by the article history. AndyTheGrump (talk) 22:05, 24 October 2012 (UTC)


 * Their approach is actually completely misleading because the astronomical zodiac constellations are in different positions than the astrological zodiac (which corresponds to arbitrary segments of sky). IRWolfie- (talk) 09:24, 25 October 2012 (UTC)

I find it mildly amusing that after User:wrk678 was complaining about missing articles, he or she found it necessary to remove my comment/question yesterday. I'll repeat it for completeness: Why is this on the science desk? Even if astrology was a science, it's an article question not an astrology question - the proper place is the astrology talk page, not here. Zoonoses (talk) 04:37, 25 October 2012 (UTC)


 * I agree with StuRat and others, that although astrology is claptrap, it is still of benefit to have extensive Wikipedia articles on it because of its cultural importance. And just because various folk dissagree in how to interpret etc, it's still not a problem covering it - articles may be written along the lines of "Common asertions include a, b, c.  etc".  However I am highly amused by this lengthy discussion on Ref Desk, for the following two reasons:-
 * 1. My father was employed as a journalist at the main newspaper company in our city. They used to publish horoscopes each day in their afternoon paper.  The editor had for years had the habit of making cadet reporters write the daily horoscope.  If for some reason a cadet was not available, one of the journos would get told to do it.  My father, a political journalist, got to write numerous horoscopes this way.  They just made them up as they typed, copying the style of previous ones.
 * 2. One of our local FM radio stations plays a daily horoscope in the mornings. They begin with a female voice saying "Here is your horoscope for today, Friday the 26th of October.  First, Aquarius... " or as appropriate for the day.  Recently they had an "open day", inviting the public to come and tour the studios & production areas.  I took a tour, and while there remarked that (a) I thought the horoscopes were a nuisance as they interrupted the music, and (b) they sound a lot like horoscopes played on another (AM) radio staion some 15-20 years before.  The programme director showing us around replied that (a) my feedback was most welcome, but many listeners, mostly females, wanted the horoscopes so they would continue, and (b) they should sound like the ones on the AM station years before, because they are the same.  There was a group in another city that made all the episodes about 40 to 50 years ago.  The relationship between the day of the week (Monday, Tuesday etc) and the date (as in 26 October) happens to repeat every 28 years.  After making 336 recordings, each covering one month, they could just keep on selling to radio stations for ever more.  For instance, the horoscope played on the local FM station this morning would be identical to that played on other stations 26 October 1984, and the same as played 26 October 1956.  Also, the station has 336 sets of day/date intros (covering 7,280 day/date combinations), but only about a 100 or so different horoscope recordings.  They just re-use them.  The original intent was that station play the day/date intro, then a commercial, and then the actual horoscope, but fortunately the local FM station doesn't insert any adverts into the horoscopes.  Originally, radio stations who purchased them were supplied with about 400 "carts" (endless loop tape catridges with auto start and stop codes on the tape), but now the whole lot is supplied on a DVD which the station loads into a computer.  The presenter just clicks on the app at the appropriate time each morning.  In theory, if no mistakes are made, the listeners would hear the day/date intros repeat every 28 years and the actual horoscope recordings repeat about every 2 years.  The horosocope for a particular day could be different on each radio station (one in each city) that has purchased the recordings.
 * Wickwack 121.221.86.108 (talk) 02:06, 26 October 2012 (UTC)
 * That's some great information - I wish we could cite you as a source for some articles. Wnt (talk) 16:14, 26 October 2012 (UTC)


 * Why 336 months? Seems to me you can do the job with 84 months (if seven of them are long Februaries). —Tamfang (talk) 19:51, 26 October 2012 (UTC)
 * I've repeated what the radio station chap told me. 336 = 7 x 4 x 12;  7 days of week, 12 months to a year, 4 years per leap year cyle.  In other words 336 is the lowest common multiple of 7 days in a week and one leap cycle's worth of months, so a given day (eg Monday or whatever) coincides with the same date (as in 27 October or whatever) each 336 months or 28 years. As it was explained to me.  However, the wikipedia article Perpetual calendar says that only 14 years plus 7 months is required - a total of 175 months.  A very simple algorithm is required to select which month to use - they don't go in sequence and each month gets used more than once in the 28 year cycle. This would not be possible when the set was supplied on numbered tape carts.  Radio presenters are selected for their personalities and nice voices, not for their ability to think, and in a radio station you definitely want to avoid room for human error as much as possible.  It simply would not do to expect them to consult a chart to find out what carts to play.  Using them is numbered sequence is ok. But bearing in mind that the station actually recieved it as software on a DVD which they installed in the studio console computer, it is quite possible the programme director (such folk are usually artistic/people types interested in music, not math gurus) was not aware of any algorithmic refinements.  I could not see where you got 84 from.  Wickwack 124.178.179.249 (talk) 05:37, 27 October 2012 (UTC)
 * In my scheme, for this month you'd use the tape marked "October beginning on Monday". You don't even need to distinguish between February 2006 and February 2012, if you rewind after the last play of the month; if the tape is a loop, then you need 7&times;13=91 tapes. —Tamfang (talk) 22:10, 27 October 2012 (UTC)
 * I think you misread Perpetual calendar. It says there are two main types: one with 14 years, one with 7 months, each with a rule for choosing which of the 7 or 14 charts to display. —Tamfang (talk) 22:14, 27 October 2012 (UTC)
 * It appears you are right on all counts. Actually, I realised after I posted yesterday that each cart could have been labelled as in "October beginning Monday" and then you would only need 7 x 12 intro carts plus the 7 29-day Februarys, totalling 91 just as you said.  But I left my post as it was because it corresponded to what the programme director told me.  It is most likely that either he didn't fully understand it (any better than I obviously did at the time) or intentionally simplified it it order to not spend too much time on it.  He said there were about "100 actual horoscopes" - it is possible he actually had the intros in mind.  He did say the actuall horoscopes would repeat about every 2 years though.  Wickwack 121.221.226.4 (talk) 00:38, 28 October 2012 (UTC)

Supersonic Newton's cradle
The steel ball in a Newton's cradle hits the other steel balls at twice the speed of sound in steel. How does this affect the solution, neglecting air resistance? 137.54.4.36 (talk) 15:54, 23 October 2012 (UTC)


 * Other than denting the balls, shattering them, breaking the suspending strings, or otherwise obliterating the device? -- Jayron  32  16:54, 23 October 2012 (UTC)


 * How would you get the ball to be moving at supersonic speeds? RJFJR (talk) 17:34, 23 October 2012 (UTC)


 * The device depends on the balls behaving as perfectly rigid objects undergoing a perfectly elastic collision (or as near as you can get in the real world). At those speeds, they would not behave in this way.  Rather, the would all fuse together or break apart. StuRat (talk) 17:36, 23 October 2012 (UTC)


 * This answer assumes the balls are indestructible and perfectly elastic and that the strings are longer than 1900km ($$h=\frac{v^2}{2g})$$ in order to contain the kinetic energy. Upon the first contact only 25% of the kinetic energy will be transferred due to the speed of sound limitation. The other 75% will be dissipated as heat. After the first strike the system will continue as normal, with the balls traveling at the speed of sound in steel at their fastest. A8875 (talk) 20:06, 23 October 2012 (UTC)


 * Terminal ballistics might be a good read. The impact of a steel ball onto a steel target is most similar to a bullet hitting an armor plate.  However, the speed of sound in steel is very fast - on the order of five or six kilometers per second - which is much faster than most conventional bullets would ever travel.  So, you're dealing with a sort of "fringe" regime - the theoretical behaviors of rigid body deformation have not been extensively validated in that range of parameters.  In fact, this is an active area of research.  Nimur (talk) 01:02, 24 October 2012 (UTC)


 * In the hypersonic limit, after the ball hits the other balls, the steel balls behave as a liquid. Count Iblis (talk) 16:01, 25 October 2012 (UTC)
 * I'm not sure that's the whole story. While the rapid conversion of macroscopic kinetic energy into thermal energy might liquify the steel, the actual material properties of solid steel are not similar to those of a liquid, scaled by the respective sound-speed.  When you say things behave as a liquid "in the hypersonic limit," I think about how conventional liquids behave above and below the hypersonic limit.  For example, a spherical droplet of water dropped on to another have a relative, macroscopic velocity that is much slower than the sound-speed (in air or water); and yet, that material behaves as a liquid on impact.  You can drop one sphere of water onto another, at below the hypersonic limit, and still get behavior as a liquid.  I think "behavior as a liquid" encompasses an orthogonal set of material properties, and physical phenomena, distinct from "a scenario where energy is conveyed at speeds faster than the material's sound speed."  Finally, plastic deformation and inelastic deformation may superficially seem similar to a splattering of liquid matter; but in fact, the properties of the motion are governed by (or at least, modeled by) a different set of equations.  All of these problems stem from the heart of the issue: how do we define a "liquid"?  This is actually a much more difficult question for physicists than it appears at first glance.  As I understand modern theories of material science, a liquid is one state of matter whose response to an external perturbation follows certain statistical rules; particularly, the way that shear translates to stored potential energy; but, when we start talking about strange regimes, outside ordinary ranges for parameters, these sorts of discussions start to become very theoretical.  Nimur (talk) 01:06, 26 October 2012 (UTC)
 * Methinks the balls would just shatter from the impact force... 24.23.196.85 (talk) 03:15, 28 October 2012 (UTC)

5 cent piece coated with copper
I got a 5 cent piece (called a nickel in the US) in my change, but it's coated in copper. Could this happen naturally, say by being in contact with copper pennies for years, or is this the result of a chemistry experiment (electroplating) ? Somehow I doubt if it could happen naturally, as only the high points come in contact with adjacent pennies, but the low points are also coated with copper. StuRat (talk) 20:21, 23 October 2012 (UTC)


 * Per this: [], it may be a nickel struck on a penny blank. I hope you didn't clean it. Dominus Vobisdu (talk) 20:37, 23 October 2012 (UTC)


 * No, the copper is worn off in places, and you can see the nickel underneath. StuRat (talk) 03:09, 24 October 2012 (UTC)


 * In that case, it may have been someone plating the nickel with copper, either electroplating or chemiplating. This is a fairly easy thing to do, because copper has a positive enough reduction potential to make it very easy to plate on other metals.  I've done similar experiments with my chemistry students.  We usually use nails for our plating labs, but you could do it with any metal object at all.  You could even do it at home with a home chemistry kit and a decent power supply.  My guess is that someone just copper plated the nickel and it got back into circulation.  -- Jayron  32  05:15, 24 October 2012 (UTC)


 * (EC)The rest of this says the most common causes are electroplating, environmental damage, and science experiments. Novelty shops used to sell them.  Zoonoses (talk) 05:22, 24 October 2012 (UTC)

Mitotic catastrophe
Is Mitotic catastrophe a subset of apoptosis? 140.254.226.204 (talk) 21:04, 23 October 2012 (UTC)
 * It looks like the view taken in the recent literature is that MC sometimes causes cell death by inducing apoptosis, but sometimes by activating other programmed cell death pathways, including one called necroptosis. Looie496 (talk) 22:58, 23 October 2012 (UTC)