:::Indeed, if one tube/duct can grow back, then why exactly can't another tube/duct likewise grow back? [[User:Futurist110|Futurist110]] ([[User talk:Futurist110|talk]]) 02:36, 27 January 2016 (UTC)
:::Indeed, if one tube/duct can grow back, then why exactly can't another tube/duct likewise grow back? [[User:Futurist110|Futurist110]] ([[User talk:Futurist110|talk]]) 02:36, 27 January 2016 (UTC)
:::::Good question. It doesn't really "grow back" in the sense of sprouting a new one from scratch. Exact vasectomy methods can vary a little ([[Vasectomy#Procedure|see the article]]), but in general the vas deferens is severed. Sometimes a portion is removed, but sometimes it's just cut, and the cut segments closed off with surgical clips or something along those lines. So, you can get minor tissue growth that winds up reconnecting the segments. Some additional procedures, like forming a tissue barrier between the vas deferens segments, have been tried to reduce the likelihood of spontaneous reversal. In general, the less [[cellular differentiation|differentiated]] a tissue is, the easier it is for it to regenerate. The vas deferens are fairly simple muscular tubes, in contrast to the epididymis and testes, which are specialized organs, so it's not surprising that you can get some regrowth of the vas deferens. --[[Special:Contributions/71.119.131.184|71.119.131.184]] ([[User talk:71.119.131.184|talk]]) 02:45, 27 January 2016 (UTC)
::::Good question. It doesn't really "grow back" in the sense of sprouting a new one from scratch. Exact vasectomy methods can vary a little ([[Vasectomy#Procedure|see the article]]), but in general the vas deferens is severed. Sometimes a portion is removed, but sometimes it's just cut, and the cut segments closed off with surgical clips or something along those lines. So, you can get minor tissue growth that winds up reconnecting the segments. Some additional procedures, like forming a tissue barrier between the vas deferens segments, have been tried to reduce the likelihood of spontaneous reversal. In general, the less [[cellular differentiation|differentiated]] a tissue is, the easier it is for it to regenerate. The vas deferens are fairly simple muscular tubes, in contrast to the epididymis and testes, which are specialized organs, so it's not surprising that you can get some regrowth of the vas deferens. --[[Special:Contributions/71.119.131.184|71.119.131.184]] ([[User talk:71.119.131.184|talk]]) 02:45, 27 January 2016 (UTC)
::<Small>Another exception is skin, which grows just fine, if given enough time (like when you gain weight). But, if you try to grow it too quickly, you get stretch marks and scars.[[User:StuRat|StuRat]] ([[User talk:StuRat|talk]]) 00:29, 27 January 2016 (UTC) </small>
::<Small>Another exception is skin, which grows just fine, if given enough time (like when you gain weight). But, if you try to grow it too quickly, you get stretch marks and scars.[[User:StuRat|StuRat]] ([[User talk:StuRat|talk]]) 00:29, 27 January 2016 (UTC) </small>
Revision as of 02:45, 27 January 2016
Welcome to the science section of the Wikipedia reference desk.
The best answers address the question directly, and back up facts with wikilinks and links to sources. Do not edit others' comments and do not give any medical or legal advice.
how do they whizz here there asnd everywhere at infinite speed to convey the force of gravity between all objects in the universe?--178.105.166.117 (talk) 01:25, 22 January 2016 (UTC)[reply]
The graviton is a hypothetical particle (not discovered yet), which is supposed to travel at the speed of light. Tgeorgescu (talk) 01:41, 22 January 2016 (UTC)[reply]
One thought experiment which I still find fascinating is that given light takes about 8 minutes to travel from the sun to the earth; IF somehow it was possible for the sun to just instantly wink out of existence, we would not have any way of knowing this had happened for 8 minutes. The sun would still be visible in the sky and the earth would keep orbiting around the now non existent sun for another 8 minutes. After that 8 minutes, we would "see" the sun disappear, and instead of following it's previously curved orbit, the earth would start to travel in a straight line the direction it was last traveling as the sun vanished. That is to say, Gravitons do not have infinite speed. Vespine (talk) 02:37, 22 January 2016 (UTC)[reply]
The thing is, no two points in spacetime can interact faster than c, so to an observer on Earth the Sun only stops existing when they see it go bye-bye. There's no way the observer could "know" the Sun stopped existing while the Sun's light is still getting to them. --71.119.131.184 (talk) 21:51, 22 January 2016 (UTC)[reply]
We actually have an article on the Speed of gravity. There is no direct measurement of the speed of gravity, though this may be possible in the future with measurement of gravitational waves. The indirect measurements that have been attempted show a speed consistent with the theory that changes in gravitational fields (and perhaps gravitons themselves) propagate at exactly the speed of light. Someguy1221 (talk) 04:06, 22 January 2016 (UTC)[reply]
If things worked any other way, there would be severe causality issues that I strongly suspect would be obvious at the galactic level. SteveBaker (talk) 04:33, 22 January 2016 (UTC)[reply]
(Strictly speaking, I don't think anything would be egregiously broken if gravity propagated slower than the speed of light—not that there's any reason to suspect such a thing.) TenOfAllTrades(talk) 19:28, 23 January 2016 (UTC)[reply]
If space is literally bent near massive objects, then the explosion of one of those objects should alter space in some kind of "ripple effect" in its gravity - extending, as hypothesized, at the speed of light. Unfortunately for us, our ability to witness the sun going nova would be very short-lived. And the earth wouldn't head off in a straight line, as the massive amount of debris from the explosion would, at the very least, start pushing us away from the sun's former location. Or more likely it would incinerate and disintegrate the earth, which would become part of the debris from the sun. On the plus side, this is not likely to happen any time soon. ←Baseball BugsWhat's up, Doc?carrots→ 15:22, 22 January 2016 (UTC)[reply]
Just a note, in my hypothetical situation, it's not enough for the sun to go nova for the gravity to disappear. In a nova only a small fraction of the mass is "used up" and the mass, whether whole or "exploded" would have the same gravity. Of course the energy of the explosion would blast everything "outwards", but disregarding that the earth would still orbit the nova, it wouldn't start traveling in a straight line. Vespine (talk) 22:41, 24 January 2016 (UTC)[reply]
Parachute jump
Suppose you are dropping paratroopers into a fairly small DZ on a windy day (but without wind shear); if you know the drop altitude AGL and the wind speed, can you calculate how far upwind of the DZ should you drop the paratroopers so they will land near the center of the DZ with a minimum of steering? 2601:646:8E01:9089:F4FA:EFCF:C9DF:C509 (talk) 02:45, 22 January 2016 (UTC)[reply]
I'm certain you can. The military would no doubt take that into consideration when deploying paratroops. Pretty much all modern parachutes are steerable, so it might not be much more than if it's light wind, deploy a bit up wind from the DZ, if there's more wind, deploy a bit further. Do that a few times and you'll quickly get the hang of how far away you have to deploy for a particular wind speed for a particular parachute. Vespine (talk) 03:05, 22 January 2016 (UTC)[reply]
Thanks! So if the wind is blowing at 15 knots and you jump from 1000 feet, you'll drift about 450 meters, right? 2601:646:8E01:9089:F4FA:EFCF:C9DF:C509 (talk) 08:17, 22 January 2016 (UTC)[reply]
It's not quite that simple:
1) Wind speed, and even direction, varies with altitude. So, you'd need to account for the drift at each level.
2) You are assuming sustained winds, but there are also wind gusts to deal with, which are, by their nature, unpredictable.
3) How far they are blown off course depends on their rate of descent. Therefore, wind will have minimal effect until the parachute is opened.
4) There's also a problem in heavy winds that once they land they could be dragged by the wind. (There is a parachute release mechanism, but using that while being dragged over rough terrain might be difficult. If they could release the instant they hit, then they would be OK, although the released parachutes blowing across the field will give away their position.) StuRat (talk) 08:29, 22 January 2016 (UTC)[reply]
Yes, you did calculate the drift D=KAV correctly using a personnel Load Drift Constant K = 3.0 meters per paragraph 6-32 and figure 6-4. But you also need to take the forward throw into account, as discussed in paragraph 6-36 and table 6-9, which is given as 229 meters for personnel out of a C-5, C-130, or C-17, and then you need to combine them vectorially with regard to wind direction and drop heading as discussed in section 6-89 and shown in Figure 6-8. There seems to be a problem with that figure in the PDF linked above by Shock Brigade Harvester Boris, so you may prefer this copy of the complete US Army Field Manual FM 3-21.38, Pathfinder Operations (with chapter 6, Drop Zones).
Note that there does seem to be an error in that manual in the "Determination of Release Point Location" section (starting with paragraph 6-89). Figure 6-8 shows all five steps, but Step 5 is omitted in the discussion, and the example given under the discussion of Step 4 (paragraph 6-93) belongs under the missing discussion of Step 5 as it is the calculation of Throw Distance, which for rotary-wing and STOL aircraft "equals half the aircraft speed (KIAS), expressed in meters." -- ToE 16:09, 23 January 2016 (UTC)[reply]
It's probably greater than that. Clearly the "equals half the aircraft speed (KIAS), expressed in meters" formula for rotary-wing and STOL aircraft does not extend to the higher drop speeds of the fixed wing aircraft in table 6-9 with forward throws of 229 meters, as there is no way that they have drop speeds anywhere near 458 knots. In fact, table E-1 gives a personnel drop speed of 130 - 135 knots. The formula breaks down somewhere, and I suspect that it is a stretch to apply at the 90 knots used in the example problem. If I had to guess, based purely on intuition, I'd be tempted to scale it with the square of the drop speed, and predict (100/135)^2 * 229 m = 125 m. -- ToE 04:36, 24 January 2016 (UTC)[reply]
It's worth noting that they very often drop supplies and weapons alongside the paratroops - and steerable parachutes don't help those things! So there is a degree of importance to making the drop in the right location. SteveBaker (talk) 17:37, 22 January 2016 (UTC)[reply]
N-A=S what these letters stand for?
In chemistry there is a formula for finding the number of the bonds. N-A=S what these letters stand for? 92.249.70.153 (talk) 14:06, 22 January 2016 (UTC)[reply]
S= N-A, where S is the total number of shared electrons, N is the total number of valence shell electrons needed by all the atoms in the molecule or ion to achieve noble gas configurations and A is the total number of electrons available in the valence shells of all the atoms in the structure. — Preceding unsigned comment added by 81.131.178.47 (talk) 15:32, 22 January 2016 (UTC)[reply]
Hi, does anyone know whether this old type of connector found in Spain has an official name or not?
Thanks in advance.--Carnby (talk) 19:13, 22 January 2016 (UTC)[reply]
Tough call. This [1] looks like a very WP:RS. It has official names and specification codes for many, many, plugs/sockets. It simply calls this type "old spanish socket". It doesn't have a picture, but the description matches these photos very well, IMO.oops; sorry :( SemanticMantis (talk) 19:56, 22 January 2016 (UTC)[reply]
Can someone give a simple, easily copied list of the most prestigious British medical schools? This inquiry is for a user who has very limited WP access, and who Wants me to send a list (category), rather than a full-blown prose article. Thanks. ````` — Preceding unsigned comment added by Medeis (talk • contribs) 21:23, 22 January 2016 (UTC)[reply]
Googling "British medical schools" gives me this. Rojomoke (talk) 22:56, 22 January 2016 (UTC)[reply]
List of medical schools in the United Kingdom is the wikipedia article for this. There are only 32 medical schools in the UK. So, there is no problem taking a look at all of them. I'm not sure what part of them are top. The Guardian score linked above could be slightly misleading. All of them seem to get scores that are not far apart.--Llaanngg (talk) 18:13, 23 January 2016 (UTC)[reply]
@Medeis: - (Position: I've done quite a bit of education consultancy work and advice with private tuition and out-of-school education) - All British medical schools essentially teach the same syllabus with the same entry criteria, so there’s a limit to how different they can be. Furthermore, by not attending a London university or Oxbridge you probably get reduced cost of living, so attending a ‘worse’ university may have dramatic compensations. Honestly, your friend probably wants to worry about getting the grades to be in a position to make that choice. From tuition work I've done I've been startled to see kids in year 10 (age 15) predicted BCC science GCSEs whose parents say they need help deciding whether they should become a doctor or a dentist. 94.119.64.1 (talk) 16:56, 24 January 2016 (UTC)[reply]
Thanks, I'll pass that on. What's actually going on (and the reason I didn't just google it, although I did send the results above) is not an actual choice of schools, but backstory for a story set in Britain. Had I been asked the same question for the US I would have suggested the University of Pennsylvania, which is top-tier, but not a cliche like Harvard or Columbia. But as an American I have no knowledge of British schools other than the obvious cliches. μηδείς (talk) 17:39, 24 January 2016 (UTC)[reply]
"Prestige" doesn't really have the same meaning WRT British academia as the Ivy League etc does in the US, other than a tendency for Oxbridge to consider themselves superior (sometimes with and sometimes without justification). Since most institutions in England and Wales (Scotland and NI are independent for the purposes of education) are charging the legal maximum tuition fee of £9000 per annum, there's a strong levelling effect since if a place starts getting a bad reputation, people will just go elsewhere. If you want a place with all the rowing-and-rugger English cliches, but avoiding Oxbridge, I'd suggest Barts. ‑ Iridescent 18:01, 24 January 2016 (UTC)[reply]
My friend agrees Barts would have been ideal, if not for Sherlock Holmes, and has settled on UCL, and I have sent the text of that article and some images. Thanks, again, for the assistance. μηδείς (talk) 20:07, 24 January 2016 (UTC)[reply]
Resolved
January 23
Developmental stage of cells and freezing
Why does freezing work when we freeze egg cells, embryos, or sperm, but does not work for higher level of development? By work I mean you can still thaw (defrost?) it and get a functional human out of it? --Scicurious (talk) 01:36, 23 January 2016 (UTC)[reply]
Probably someone else will provide more details but our article Cryopreservation and to a lesser extent Cryobiology and Cryonics has some details. Note that your idea freezing just works is largely incorrect. For both Embryo cryopreservation and Oocyte cryopreservation, you have to carry out an effective method of cryopresevation or you're most likely not going to have much success. Notably as our article says, human oocyte cryopreservation is still a relatively new technique. (As embryo cryopreservation is older, some women have frozen embryos which were fertilised by a former partner, which can lead to problems if the partner does not wish the embryos to be used.) Even Semen cryopreservation generally uses some method although the large number of sperm in a normal sample means you have a larger margin for error. Nil Einne (talk) 04:15, 23 January 2016 (UTC)[reply]
Yes, I mean "freezing an egg cell works" (somehow works, by proper procedure). I.e. it's possible. This is contrary to "freezing a baby", which never works, no matter what you do. I.e. you won't be able to reactivate it. --Scicurious (talk) 13:51, 23 January 2016 (UTC)[reply]
[citation needed] for your final statement. AFAIK, and this is supported by the articles I linked to, there's no intrinsic reason based on our current understanding to think it's impossible although it is likely to be very difficult. The reasons why it's so much more difficult with a whole organism where you have to successfully freeze and revive the vast majority of cells in a complex large (in all dimensions) system are given in the article, although many of the, should be obvious with a bit of understanding of ow cryopreservation techniques work and biology and physics. And you already see similar issues when comparing sperm vs oocytes or embryos. Nil Einne (talk) 14:32, 23 January 2016 (UTC)[reply]
BTW, my comments and questions have a definite purpose. They are important because if you have a fundamental misunderstanding of what is and isn't possible and how it is and isn't possible; this may very well be one of the reasons why you're having trouble understanding why whole organism cryopreservation for organisms with large & complex body structures like humans (or even Drosophila[2]) is very difficult. And it's not like it hasn't been achieved for adult organisms with simpler body structures like various nematodes[3]. P.S. I don't intend to suggest complexity and size are the only factors although they are big ones. For a variety of reasons certain things may actually be easier to cryopreserve than you would expect comparing to something else. Also I don't think cryopreservation of vertebrates is an active area of research and definitely not dogs or cats or even rats. But cryopreservation of organs is to some extent [4]. This shouldn't be that surprising, if you can't even really cryopreserve a rat heart yet, cryopreserving a whole rat is very unlikely. Nil Einne (talk) 15:42, 23 January 2016 (UTC)[reply]
The problem isn't related (trivially) to stage of development, but to size and complexity. We can readily freeze and thaw many types of mature human cells. What we can't (usually) do is freeze large pieces of animal tissue. That is to say, we can freeze, store, and revive primary cardiomyocytes, but not hearts; we can freeze, store, and revive primary hepatocytes, but not livers; and so forth. TenOfAllTrades(talk) 18:41, 23 January 2016 (UTC)[reply]
Why we stop producing lactase as adults?
I have read about being lactase persistent is an advantage for survival. Only 10% of the world population are lactase persistent as adults. The 10% that are lactase persistent are results of a mutation occurred thousands of years ago. We are all born with lactase persistent as babies then lose it as adults. My question is why do we lose it as adults? If that was an advantage, why natural selection turned it off during adulthood? Why most people were not lactose persistent until mutation kicked in? All the answers to this question "why" I found online include something like because we don't need milk as adults anymore. Yes, sure, while we don't need milk as much as we do as babies, but it is still considered to be an advantage. Just because we don't need something doesn't mean that thing doesn't have an advantage. That doesn't answer why the gene is turned off in adulthood. Why natural selection was not at work until much later when some new mutations kicked in? Thank you! (p.s.: I don't care about the mechanisms and any other matters; the answers should focus only on the why aspect). 146.151.96.202 (talk) 06:37, 23 January 2016 (UTC)[reply]
Because producing lactase uses energy, which takes energy away from other stuff? That's the best answer I can give you. 2601:646:8E01:9089:90DA:8B23:BEB4:5241 (talk) 07:55, 23 January 2016 (UTC)[reply]
As is explained in our article Lactase persistence, it was not an advantage in societies that didn't have dairy farming so it was turned of in adulthood. it was only turned back on in societies that had developed dairy farming. Richerman(talk) 11:23, 23 January 2016 (UTC)[reply]
Okay, even if it wasn't an advantage in societies that didn't have dairy farming, but it was not an disadvantage either. Why was there the need to turn the gene off as adults? 146.151.96.202 (talk) 21:04, 23 January 2016 (UTC)[reply]
There might not have been a need. Maybe it was just a random mutation for no purpose, and with no down side. But if people weren't dairy farming, there would be no natural selection to weed out these mutations, so they would spread through the population until most/all had them. Note: I said "people", but this would have actually happened long, long ago in the early history of mammal evolution. It wasn't until some populations of an advanced ape started raising dairy herds that the reverse mutation became useful. Iapetus (talk) 12:03, 26 January 2016 (UTC)[reply]
Infant mammals have only one oral activity which is suck-swallow-breathe and this represent a drain on maternal resources until they develop the skills of eating and swallowing solids. Mammals have various way of encouraging infant skill development as soon as possible, which is an evolutionary advantage in the wild. Lactose intolerance i.e. cessation of Lactase production that causes the infant animal to experience stomach upset if it persists in breast feeding, contributes to the infant seeking independent nutrition.
Are you saying the gene was turned off in adulthood is the natural selection way of encouraging infant independence of its mother? If lactose persistent population can be independent without the gene turned off, this argument doesn't seem to hold. The gene does not need to be turned off for the babies to seek independence. The mother can teach the babies to be independent. I see no harm in keeping the gene on. Why it was turned off in the first place is puzzling me. 146.151.96.202 (talk) 21:02, 23 January 2016 (UTC)[reply]
No. Contribute to means help to cause or bring about (Oxford Advanced Learner's Dictionary). It attacks a Strawman to say this argues the cessation of Lactase production is "the essential natural selection way". Do you also need to be given a justification for each developmental change from infant to adult such as loss of Umbilical cord, loss of primary teeth, and loss of Moro reflex? AllBestFaith (talk) 01:57, 24 January 2016 (UTC)[reply]
I thought the usual idea was that, if older children kept nursing, they would compete with their younger siblings, to the disadvantage of the latter.
Of course the mother could prevent that. But would she? The same question applies to the "independence" version, actually. It's not absurd that there might turn out to have been an evolutionary advantage in making the weaning more automatic. --Trovatore (talk) 21:36, 23 January 2016 (UTC)[reply]
Trovatore. "The same question applies to the "independence" version." Can you explain more what do you mean by this statement? And why wouldn't the mother prevent that? It makes sense that the mother would make the older siblings seek independence, so that she could feed the younger ones with her milk (since the young ones are unable to eat solid food yet). It's entirely possible to become independent without turning off the gene as happened with cultures that are lactose persistent. Again, I see no clear advantage in turning off this gene.146.151.96.202 (talk) 20:21, 24 January 2016 (UTC)[reply]
Some human populations have developed Lactase persistence, in which lactase production continues into adulthood. It may have developed as a response to growing benefits of digesting the milk of farm animals such as cattle. Research reveals lactose intolerance in humans to be more common globally than lactase persistence and the variation has been tied to genetics, but that the largest source of variation has been shown to be based on exposure (e.g., cultures that consume dairy). P.S. Sensible consideration of evolutionary factors should identify probable mechanisms without which answers to "why" are only speculation.
I don't know where there is something about this but I think I also read somewhere there is an advantage in stopping the transmission of diseases in having children be appreciably different from adults in various ways, so there is a drive to accentuate differences. Dmcq (talk) 15:21, 23 January 2016 (UTC)[reply]
Video and scientific racism
Video in question. Most scientific racism came from whites during the age of scientific racism, but this particular video has it coming from a black man. I know evolution is not a ladder and lifeforms don't become "better" or "degenerate" as they mutate, they merely adapt to the environment, but I was curious if anyone had any direct refutations of what this man is saying. ScienceApe (talk) 17:00, 23 January 2016 (UTC)[reply]
There are plenty of easily found analyses of scientific racism. You appear to be asking this question just to show us that a black man can be a "scientific" racist too. --Llaanngg (talk) 18:15, 23 January 2016 (UTC)[reply]
(edit conflict) In the unlikely event that this is a genuine question and not a piece of trolling, there's an explanation of this particular theory and the arguments around it at Melanin theory. ‑ Iridescent 18:55, 23 January 2016 (UTC)[reply]
What points do you want us to refute? There's no scientific racism involved in the video, the guy is a racist talking garbage with almost no science involved. He claims that white people are a different species to black people and then a few seconds later says that they are the same species. His claims that white people are more prone to depression and violence isn't supported by any research (obviously there are some studies that would support that claim, while other studies would show that black people are more prone to depression and violence). I'm not sure what the 'SAR' gene is that he mentions, but if white people were that prone to a genetic problem it would be common knowledge, not posted by an idiot on youtube 95.146.213.176 (talk) 00:13, 24 January 2016 (UTC)[reply]
As I said above, this is not really a question, but a means to spread the word about this deluded black racist. --Llaanngg (talk) 02:05, 24 January 2016 (UTC)[reply]
You really think I was trying to spread the word about this guy? I can assure you I wasn't. I was hoping for a direct refutation of the things he was saying. If I was trying to spread his word, I think twitter or facebook would be a better venue don't you think? ScienceApe (talk) 17:26, 24 January 2016 (UTC)[reply]
I know people are having a knee jerk reaction to this video which is understandable. I agree, he is an idiot, I was hoping for a refutation of the points he was saying though. He didn't say white people are a different species, he said they are the same species. As for the points I want you to refute, he mentions "SARA" makes white people more violent. Do white people possess this gene at a higher level as he alleges and what does it do? He also alleges that slc2485 gives them pale skin and alleges that it was developed in central asia. At 1:15 he mentions something but I can't make out what he's saying, but he alleges that it gives them straight hair. He goes on to say that 3%-4% of white DNA is from neanderthals. He alleges that they are able to cope with cold weather from the creatine in their skin. He then says at the "demi level" that 4% stretches out to 70% of their skin. These are some of the allegations he's making. Like I said, I'm not saying he's being rational nor am I defending what he's saying. I just want to know if the assertions he's stating are correct or not. ScienceApe (talk) 17:35, 24 January 2016 (UTC)[reply]
While I didn't catch the part where he called them a seperate species (he did say something about some people feel they are "something different" and it's cool and people should feel like that), I largely stopped listening when he mentioned demi level. Since "demi level" is not even close to a scientific concept, it's not surprising if the rest of his talk is similarly unscientific. Nil Einne (talk) 00:48, 25 January 2016 (UTC)[reply]
I don't even know what demi level means. ScienceApe (talk) 02:22, 25 January 2016 (UTC)[reply]
Um isn't that precisely the point? We don't know because it isn't a scientific concept and this is a science desk. If random people are talking random crap in videos where one of their basic points refers to non scientific concepts, then there's little point analysing their videos to find if any of it has any scientific merit in any of what they say. If you don't have sufficient knowledge to dismiss demi level offhand, a simple search will show it's not a scientific term. It's possible that it's simply an incorrect name for a common concept (which considering the person talking clearly speaks good English even using their personal cultural variant is a warning sign in itself); but if there's uncertainty over whether demi level is actually referring to any scientific concept but by the wrong name, it makes sense to ask about that rather than getting in to nitty gritty over whether claimed gene frequencies are correct (let alone whether these genes have any well established link to violence). 09:00, 25 January 2016 (UTC)Nil Einne (talk)
I don't necessarily think we should throw the baby out with the bathwater so to speak. He mentioned other things which may very well be scientific. "SARA" and slc2485 for example. But I agree that "demi level" could in fact be the incorrect term for a real scientific concept. So if that's the case, what is that concept? ScienceApe (talk) 16:56, 25 January 2016 (UTC)[reply]
I think you've missed my point. I never said that demi level may be a real scientific concept. I only said if you were initially unsure if demi level was really just a poor name for a scientific concept, you should have asked. You should have already established that demi level is not the real name for a scientific concept by yourself (as that is trivial to establish, there's basically no one else talking about it), so your main question should be "is he just using an uncommon name or is he talking nonsense"? But I already said in my first reply that it was not scientific concept and he is talking nonsense. And as I also said, when people are talking science but get the basics of what they are talking about fundamentally wrong, it does make sense to throw the baby out with the bathwater. Or just to repeat what I said in my first reply Since "demi level" is not even close to a scientific concept, it's not surprising if the rest of his talk is similarly unscientific.Nil Einne (talk) 13:44, 26 January 2016 (UTC)[reply]
'Demi level' means 'half level' which makes absolutely no sense in his context (so you can ignore that nonsensical claim). 'sarA' appears to be a gene related to viruses [5][6]. White people aren't more prone to 'violence inducing afflictions' from viruses, so that's another argument you can strike out. The SLC gene family is involved in melanin production, so naturally all races have different SLC genetics [7]. How could you expect an albino to have the same SLC genes as a black? 'slc2485' (according to a quick google search) is specifically a gene involved in the production of melanin, in combination with other genes, but there's no evidence I can see showing that it might cause violence. I'm not sure why you still insist that something about that video might be scientific, it's blatantly a racist video, and I hope I've responded to all your queries about anything that might have been scientific Mike Dhu (talk) 20:39, 25 January 2016 (UTC)[reply]
After a bit more research I think what sounded like 'slc2485' must be SLC24A5, so you could follow that up if you want to. There's some info about its role in skin colour but there's no mention of violence related to the gene. Mike Dhu (talk) 21:58, 26 January 2016 (UTC)[reply]
Why does powdercoated metal, like the inside walls of a microwave, not spark?
Small amounts of metal won't spark. ScienceApe (talk) 23:44, 23 January 2016 (UTC)[reply]
Small amounts of metal certainly will spark - have you never put a cup or plate with a gold leaf rim in a microwave? Whether a piece of metal arcs or not depends on it's shape - thin edges or points tend to build up a charge and arc (spark). The side walls are flat with no edges so the microwaves are reflected back and don't build up a charge. Other metal components, such as the metal rack, are designed without points or sharp edges for the same reason. Richerman(talk) 00:54, 24 January 2016 (UTC)[reply]
(ec) A metal object in the cavity of a microwave oven can produce sparks if it concentrates the electric field sufficiently to cause breakdown of the air. Whether this is the case depends on the size, shape, position and orientation of the object. A metal object with sharp edges is likely to concentrate the field at the edges, particularly if the size of the object is such that the electric currents on it resonate at the frequency of the applied field (~2.45 GHz). The walls of the cavity do not give rise to sparks because they lack extremities with convex edges, rather than because they coated. --catslash (talk) 01:18, 24 January 2016 (UTC)[reply]
Additionally, the fact that the cavity of a microwave oven is made of metal is essential to its operation. The walls of the oven form a Faraday cage, trapping the microwaves inside the oven. If your microwave has a window, you might have noticed the metal grating over it. This is also part of the Faraday cage. The openings in the grate are smaller than the wavelength of microwaves, so microwaves cannot pass through them. Visible light has a much shorter wavelength, so it passes through just fine. --71.119.131.184 (talk) 01:55, 24 January 2016 (UTC)[reply]
I think ScienceApe meant small in size. Each granule of the powdercoat metal is insulated from the next granule, so there is no large voltage induced. The gold leaf rim will not spark if it is cut into small sections. Dbfirs 09:15, 24 January 2016 (UTC)[reply]
Thanks. So you're all saying a smooth steel ball bearing with no small bumps or surface defects could be microwaved without sparking? 75.75.42.89 (talk) 22:06, 24 January 2016 (UTC)[reply]
It's not that simple - to quote from here "metal in the oven has to have a certain shape, size, alloy, distance from other pieces etc. or it will really do unpleasant things like arc and get dangerously hot. The rules are complex and as the average microwave oven owner doesn't have a post-graduate degree in physics with at least a minor in high-energy radio it's just easier to say "no metal." Richerman(talk) 18:24, 25 January 2016 (UTC)[reply]
Well one of the microwave ovens I had had a nice folder showing that when idle, you should put in it a glass full of water with a 100% metal teaspoon in it. The water would absorb energy if it started by chance and the teaspoon would avoid hyper-heating, allowing it to boil. There are YouTube videos with microwave ovens with forks and spoons put inside them. Tgeorgescu (talk) 00:41, 26 January 2016 (UTC)[reply]
Seems to me like it would be a much better idea to just unplug the oven, if you're worried about it being turned on while empty... --71.119.131.184 (talk) 00:28, 27 January 2016 (UTC)[reply]
January 24
"freeform" electromagnetic coils
1. What's the proper name for these "freeform" electromagnetic coils[8]?
2. How are they made? Roughly which one of the following guesses is the closest?
A) wind one layer, spray some adhesives, and then wind another layer on top
B) Adhesives are added continuously as the winding continues
If there were a coilform with a central cylindrical core and endpieces, the coil could be wound as shown by rotating the coilform while the supply bobbin moved slowly back and forth via gearing to lay down straight layers. The endpieces could then be removed and the wound coil pushed off the central cylinder. The wire would tend to maintain its form, but clearly it would deform if stressed. It could be dipped in varnish to cement it together into a rigid form. Edison (talk) 05:05, 24 January 2016 (UTC)[reply]
Is the [9] one that you uploaded yourself or that you have information about? It is not obvious from the picture alone that this is intended to be an electromagnetic coil as it has no terminals, no adhesive can be seen and the wire could be uninsulated (not magnet wire). A spool of plain wire delivered from a factory could look like this. AllBestFaith (talk) 16:15, 24 January 2016 (UTC)[reply]
They are called 'self supporting' coils.--178.102.247.97 (talk) 17:41, 26 January 2016 (UTC)[reply]
Analogue live TV
Before digital "film", how was live television done? My mental image of television, pre-digital, was that the scene was recorded by a videocamera and microphone, the sounds modulated onto electromagnetic waves as with radio, the film developed and then the images somehow modulated onto electromagnetic waves, and chronological conjunction between the two processes is enforced to ensure that the video and sound be synchronised. This doesn't seem to fit with live TV, however, as there's no time to develop anything; how would it be possible to broadcast anything that wasn't a recording? Today, it's easy: you can basically use the same techniques as Skype, but that wasn't possible in the 1950s. Nyttend (talk) 05:40, 24 January 2016 (UTC)[reply]
Television cameras before the 1980s used video camera tubes. Basically they worked like a CRT television in reverse. In a CRT display, one or more tubes scan their beams across the screen to produce the picture. In tube cameras, the camera focuses incoming light onto a target and one or more tubes scan the target. --71.119.131.184 (talk) 05:50, 24 January 2016 (UTC)[reply]
Note also that for quite a long time, a lot of prerecorded stuff on TV was direct on to Videotape not film. In fact, sometimes the content may have gone from videotape to film.
And BTW home camcorders weren't that uncommon before everything went digital. America's Funniest Home Videos for example was before digital video was particularly common, and some Youtube videos also look they were probably recorded on analog tape.
Let's put it this way. You (Nyttend) have the mental image "that the scene was recorded by a videocamera". But that's really two things: converting the scene into an electronic signal, and recording the electronic signal. In a live breoadcast, the electronic signal would be used directly (more or less) to modulate electromagnetic waves just as the audio signal is used in radio. (For live color TV it would also be necessary to convert the R/G/B signals from the camera into the applicable encoding, i.e. NTSC, PAL, or SECAM.) --76.69.45.64 (talk) 07:22, 24 January 2016 (UTC)[reply]
Incidentally, the processes Nyttend describes is John Logie Baird's "Intermediate Film Technique", used for a few months in 1937 in the UK, but obsolete since then. It introduced a delay of about 1 minute in a live broadcast - see this article. Tevildo (talk) 09:03, 24 January 2016 (UTC)[reply]
Germany transmitted film-intermediate TV earlier. [10] During the 1936 Summer Olympics experiments were conducted with both an analog electronic camera and with a mobile TV truck. On the roof of the truck was a film camera. The film was developed in the truck and then run through the transmitting apparatus. AllBestFaith (talk) 17:09, 24 January 2016 (UTC)[reply]
Live TV originally went "straight to air", with no intermediate recording and playback steps. The signals from the microphones and camera were combined (usually through vision mixer and audio mixer desks) into a composite signal which was distributed to the transmitter site, modulated onto an RF carrier, and broadcast. All of these were real-time analog processes, with no delay except for that inherent in signal processing and propagation. The Anome (talk) 10:09, 24 January 2016 (UTC)[reply]
The Anome has hit on it. Just like a phone call, there is no need for a TV camera and transmitter system to make a permanent record of anything: if you have an outside broadcast unit you can just turn on a camera, transmit that signal to a control centre and then put it out on the air, without at any stage 'recording' it permanently. Much early TV was broadcast live without any copy of it being kept. Before the days of cheap magnetic recording systems, if you needed a permanent record of it, you'd often literally just film a television set with a film camera. Similarly, most analogue phone calls have never (one assumes) been permanently recorded onto anything. They just go from one phone to another through the wires. Blythwood (talk) 13:02, 24 January 2016 (UTC)[reply]
Thanks to everyone! I had no idea that it was possible for the TV camera to do anything except impress each scene on a separate film still; I didn't know that they used CRTs to send imagery to a transmitter. I'd imagined that the first cameras of any sort that used neither film or U-matic videotape were digital cameras. Nyttend (talk) 15:26, 24 January 2016 (UTC)[reply]
U-Matic was really quite a late development. There's a lengthy history of different types of analog video format, starting, I believe, with two-inch quad, and I believe digital videotape made its first commercially successful appearance with the advent of D-1 recording. -- The Anome (talk) 23:58, 24 January 2016 (UTC)[reply]
I'm fairly confused why the OP is conflating video tape and film. The distinction here is IMO important because while it's easy think a camera which is exposing light on to film would not be able to modulate an EM signal, if your camera is already modulating a signal onto video tape it's harder not to see the possibility of bypassing the video tape step completely. Of course when you think about it more, even with film, you have to modulate the signal somehow. If you are doing this by shining light through the processed film and then using the resulting image to modulate a signal, why can't you just skip the step of going from light to film to light?
In any case, note that beyond broadcast TV, it wasn't that uncommon for CCTV systems to be display only, which was I believe the initial form of CCTV per our article.
The modern equipment for conversion from movie film to electronic TV signal (for taping or immediate transmission) is a Telecine. AllBestFaith (talk) 17:21, 24 January 2016 (UTC)[reply]
@Nyttend: - as a related point, early video recording on magnetic tape was so expensive that often even when TV was recorded down onto tape or a film, the tapes were soon wiped over and reused - often tony TV executives seem really to have thought that this junk they were producing was surely of no lasting interest to anybody. The result is that much TV made as late as the mid-1970s, even in prosperous and stable countries and even by state broadcasters with a high image of themselves, was erased. So yes, a lot of early TV was sent through the TV broadcast system like a phone call, with no recording device of any kind set up to make a record of it for posterity. Blythwood (talk) 10:52, 25 January 2016 (UTC)[reply]
As an interesting example, when the BBC broadcast the first UK TV play of George Orwell's Nineteen Eighty-four on 12 December and 16 December 1954, the actors (and backing orchestra) had to perform the play live twice, as the first performance had not been recorded (except for small segments, such as outdoor scenes.) The second performance was, however, recorded for archiving, perhaps because its importance had become obvious. {The poster formerly known as 87.81.230.195} 185.74.232.130 (talk) 15:07, 25 January 2016 (UTC)[reply]
Fans of the BBC Doctor Who series are particularly aware of this. Being obsessive collector-ish people - they'd like to have every episode ever made, nicely recorded. But since the series started in 1963, many of the episodes were recorded on magnetic tape and subsequently wiped. Interestingly, many of the episodes that have been recovered were recorded by people watching the show on broadcast TV who points 8mm film cameras at the screen - others were duplicated and shipped to other countries who wished to show the series and the master copies subsequently erased. Fans of the show periodically find a recording of a long-lost episode by digging around in piles of junk in places as far afield as Nigeria and Dubai! Often the sound track of the tape has been over-dubbed with something else and someone's home audio-cassette bootleg has been synced to video from elsewhere to cobble together a low-quality version. It's hard to imagine the cost of a recording tape being even a tiny fraction of the cost of making a 30 minute TV show - but evidently that was the case because such a vast number of TV shows from that era are either lost forever - or would require the sheer determination of an army of Dr Who fanatics to track down the remaining scenes put them back together. SteveBaker (talk) 17:29, 25 January 2016 (UTC)[reply]
Considering starting a new project on here
Hello all! As a spare time project, I’m looking to do spend some time in the next few months messing around with R, its graphics packages in particular. I’d be interested in combining this with my contributions to Wikipedia (do two obsessions together!) - does anyone have suggestions for any publicly available molecular biosciences data that might be interesting to do something with? Preferably something I can't screw up too badly! Blythwood (talk) 11:43, 24 January 2016 (UTC)[reply]
A while back I got to messing with Module:ImportProtein, which is in Lua (see the talk page for an example), and like so many things... put it aside for "a while". If you're interested, I'm not reserving the copyright. :) I wasn't aware of any direct R integration with Wikipedia, though it would create interesting possibilities! Wnt (talk) 14:25, 24 January 2016 (UTC)[reply]
Some aspects of it might be too close to original research, which is fine for other places, but not welcome in wikipedia. On the other hand, you could research numerical data already on Wikipedia and plot it in a more visual way. --Scicurious (talk) 15:40, 24 January 2016 (UTC)[reply]
@Scicurious: - sure, but I'm more interested in creating graphs as example images, and would be very happy using made-up data that's relevant to a real situation. So 'here is a data visualisation of type X to show what it looks like' - I would be happy to put a disclaimer explaining that the data is fictional. Blythwood (talk) 23:39, 26 January 2016 (UTC)[reply]
Did the universe start with only neutrons?
If hydrogen fusion created all other atoms from hydrogen, and hydrogen is a proton and an electron, and fission reaction is the decay of a neutron into a proton and electron, then did the universe start with only neutrons?
— Preceding unsigned comment added by 86.153.69.165 (talk • contribs)
Our current theories imply that there were subatomic particles before neutrons existed; and it seems like neutrons and protons both started emerging roughly around the same time. Have a read through Chronology of the universe, Quark–gluon plasma, and related articles.
I think your insight is good, in that you're looking for reverse- reactions (like beta decay) and trying to conserve charge; but you are missing some important complications that arise when we study sub-nuclear particles in great detail. We now know that there are lots of valid ways that we can break protons and neutrons apart if we use very high energies. Present theories for the early universe imply that our heavy particles were created around the hadron epoch after protons and neutrons coalesced from quarks. Before that time, the energy density was so high that we barely understand the rules that govern quark combination: what we do know is that there were no protons or neutrons yet.
On Digikey in the diode section[11], what does the "schottky, reverse polarity" diode type stand for? I understand what a regular Schottky diode is, but am not sure what a reverse polarity Schottky diode is. Johnson&Johnson&Son (talk) 15:05, 24 January 2016 (UTC)[reply]
Could it be a Schottky diode for creating a reverse polarity protection?--Scicurious (talk) 15:47, 24 January 2016 (UTC)[reply]
The OP has linked to a diode selection guide where one chooses filter(s) to limit the selection. Applying the "Schottky Reverse Polarity" filter reduces the number of manufacturers (to 2) and introduces selection menus for reverse leakage and capacitance when reverse biased. They are all Schottky diodes and this is just the guide designer's way to offer a detailed reverse specification if needed. AllBestFaith (talk) 16:42, 24 January 2016 (UTC)[reply]
The reference is to the packaging. The standard D-67 package has the cathode as the base and the anode as the lug, and the standard DO-4 package has the stud as the anode and the terminal as the cathode. The "reverse polarity" diodes listed have the anode as the base for the D-67 packages, and the cathode as the stud for the DO-4 packages. Tevildo (talk) 18:44, 25 January 2016 (UTC)[reply]
I don't appreciate being accused of trolling. If I wanted to troll, I would ask a bunch of nonsensical questions using multiple sock puppet accounts so you didn't know they were from the same person. ScienceApe (talk) 17:19, 24 January 2016 (UTC)[reply]
Maybe you are doing it, but was not caught yet. Anyway, it's difficult to see a purpose on your questions sometimes. Maybe you should perform a simple search for a question before you ask it here. Otherwise you would look more like a science ape, than as a science curious person. --Scicurious (talk) 17:50, 24 January 2016 (UTC)[reply]
I don't need to prove I'm not a troll, but you're free to believe whatever you like, however I'm not going to stop asking questions if I'm curious about something. However feel free not to respond to my questions. ScienceApe (talk) 20:41, 24 January 2016 (UTC)[reply]
Of course you don't need to prove anything. However, if you are disruptive on wikipedia including the RD by continually asking pointless questions, you should expect to be restricted. Even if you don't reach that level, you should expect to be ignored, even when you ask okay questions if you continue to ask pointless questions. Nil Einne (talk) 00:15, 25 January 2016 (UTC)[reply]
Ok well then you can report me and try to get me blocked, but your threats are not going to dissuade me from asking questions. ScienceApe (talk) 02:19, 25 January 2016 (UTC)[reply]
A real life reference librarian who frequently scolded patrons for not just looking stuff up themselves would soon be fired. If it makes someone that angry when someone asks a question that is easy to find an answer for, then the angry librarian should find other areas of Wikipedia in which to work. It is disruptive to scold people who ask question when it is not clear they are trolling, as it is not clear here.Edison (talk) 20:49, 24 January 2016 (UTC)[reply]
Thanks I appreciate that. If nothing else, this should have been kept to talk pages and off the reference desk. ScienceApe (talk) 02:19, 25 January 2016 (UTC)[reply]
I agree that you are entirely entitled to ask questions that can be answered by typing the question into google - and calling you a troll is hardly WP:AGF. We've even had questioners here for whom Wikipedia was the only website they were allowed to access! However, it might be nice to try Google first. It's different when someone is a first-time user, and we all occasionally get the wrong form of words and google doesn't help - but as a regular question-asker, it would be a courtesy to the volunteers here to at least give it a shot before posting. SteveBaker (talk) 14:48, 25 January 2016 (UTC)[reply]
We should compare with some of the alternatives available at the time:
1) Iron pipes: These can rust. While a small amount of added iron in the diet may actually be healthy, in antiquity people didn't know that iron pipes were healthier than lead. Also, the orange or brown water it produces doesn't look or taste good. And eventually the pipes can rust through. (There are water treatment methods to prevent rust, but they wouldn't have had those in antiquity, either.)
2) Ceramic pipes: These can crack, due to seismic activity, frost-freeze cycle, tree roots, or subsiding of the ground around it. Therefore, they tend to be leaky.
3) Copper pipes: These can corrode to produce green sludge and eventually fail from that corrosion. Similar to iron, a bit of added copper in the diet may actually be healthy, but they didn't know that in antiquity.
So, if you didn't know about lead poisoning, lead pipes seemed like a good option (or gold pipes, if you happened to be filthy rich). StuRat (talk) 17:39, 24 January 2016 (UTC)[reply]
Wooden water pipes were popular in London for mains water supply in the 16th to 18th centuries, but generally connected to lead pipes in peoples' houses. I believe that they were still being replaced in the 1960s. IIRC they were generally made from Elm wood which is resistant to rot when not exposed to air. Alansplodge (talk) 18:02, 24 January 2016 (UTC)[reply]
Yes, I forgot about wood. Bamboo can be used, too, since it's naturally hollow, although some type of sealant may be need at the joints. StuRat (talk) 18:51, 24 January 2016 (UTC)[reply]
My gut feeling is that this would have to do with metal prices - alas that article, unfortunately, doesn't contain even a current table, let alone historical data. It would be worth updating with information from various sites like this. But my impression is that lead is a cheap metal because it is not usable for very many things, and a pipe buried in the ground is one case where the weight and the softness don't count against it. Alas, even that didn't pan out in the end... Wnt (talk) 20:38, 24 January 2016 (UTC)[reply]
Lead works reasonably well for large diameter pipes (ratio of surface area to volume of water being smaller) - providing that the water is flowing quickly through the pipes and doesn't contain chemicals that corrode it. It follows that lead pipes are a reasonable solution for the mains supply (large diameter, water constantly moving) - but a terrible choice for houses (small diameter, water standing still for a dozen or more hours at a time).
In the news right now, the children of Flint, MI are suffering the consequences of using corrosive chemicals in lead pipes that had functioned acceptably (without those chemicals) for decades. Their problems were that e-coli in their water supply had to be treated aggressively - and that treatment caused the lead in the pipes to dissolve into the water much more easily.
Obviously, with modern plastics that are cheap, more or less completely inert, and which will probably last for centuries, we have the technology so that we don't have to suffer any of the issues that come with lead pipes anymore. However, the cost of digging up streets to replace them is more than many communities can bear. Flint was desperately short of money - which is why they switched water supplies in the first place - and replacing those old lead pipes was evidently not an option.
They normally put chemicals in the water to coat the pipes to prevent corrosion, but when Flint switched water supplies they stopped adding those critical chemicals, and once the old ones wore off the inside of the pipes, corrosion began. StuRat (talk) 20:57, 25 January 2016 (UTC)[reply]
Where can I find the coefficient of friction between nickel and polyethylene? Actually the coefficient of friction between nickel and any common plastic would be fine.
I found this site[12] that has the data for nickel and Teflon, but Teflon is little too difficult for me to get my hands on. Johnson&Johnson&Son (talk) 17:10, 24 January 2016 (UTC)[reply]
The coefficient of friction of plastics is usually measured against polished steel. PTFE (Polytetrafluoroethylene, brand name Teflon)'s coefficient of friction is 0.05 to 0.10. Polyethylene can be supplied in various grades for which this supplier quotes coefficients of friction 0.18 to 0.22. That is for steel. This table gives some comparison with nickel. AllBestFaith (talk) 17:55, 24 January 2016 (UTC)[reply]
Thanks. But the problem is I don't have a steel part; I have a part that's coated in nickel. Is there a way to derive or approximate the nickel-plastic CoF given the steel-plastic CoF? The engineershandbook.com[13] link you gave has nickel-glass, nickel-nickel, and nickel-steel CoF listed, but unfortunately it doesn't have any for nickel-plastic. Johnson&Johnson&Son (talk) 02:40, 25 January 2016 (UTC)[reply]
Look for firearms information. Nickel coated bolt carriers and nickel-teflon triggers are common. --DHeyward (talk) 05:14, 25 January 2016 (UTC)[reply]
January 25
Why do Northeast Megalopolis snowstorm records look like this instead of a northern bias?
Does the distribution of water vapor by latitude have anything to do with it?
How sure are scientists that climate change will make single snowstorm records easier to break in the future? Sagittarian Milky Way (talk) 00:15, 25 January 2016 (UTC)[reply]
Let me speak to the relationship between how far north (or south, in the Southern hemisphere) you are and the amount of snow you get. The closer to the poles, the lower the temperatures. At low temperatures, less moisture evaporates from lakes, rivers, and oceans, especially once they freeze over. This makes for less snowfall. Therefore, there is very little snow at the South Pole, but, since it rarely melts, you see thousands of years worth of snowfall on the ground at once.
Now, this doesn't necessarily affect the snowfall amounts in this particular storm, as many other factors and local conditions are also more important, but it is a general trend. In fact, many of the places with the heaviest snowfalls historically are places which get lake effect snow, where air moves over warm water, picking up water vapor, then depostits it once it moves over colder land. Buffalo, New York is one such spot, with Lake Erie providing the (relatively) warm water. StuRat (talk) 00:49, 25 January 2016 (UTC)[reply]
Locations move. Equipment and methods change. And the forecast has uncertainty [14]. There is no reason to believe any of it is related to climate change as climate change has still remained unmeasurable as an observation of weather. --DHeyward (talk) 05:54, 25 January 2016 (UTC)[reply]
One might term this ocean-effect snow, as it involved water vapor being swept off the relatively warm ocean surface (warmer this year because it's a strong El Nino year) and meeting an Arctic air mass over the continent. It's a classic (several authorities are saying textbook) example of explosive cyclogenesis and it's a product of North American geography. The warm water of the Gulf of Mexico and consequent moisture streams and the presence of the Gulf Stream favor large snowfalls relatively far south. However, these snowfalls tend to be intense rather than frequent, so total snowfall over a season will be higher farther north where it's colder and stays colder for a longer time, but where there is less access to subtropical moisture. Topography helps too - the Appalachian Mountains lift moisture to colder altitudes and it rains or snows out, leaving places like Pittsburgh relatively dry in these kinds of storms. Some of the same geographic elements give rise to Tornado Alley in the spring. Warm moist marine air meets cold dry continental air, and boom. Acroterion(talk) 15:11, 25 January 2016 (UTC)[reply]
A rare case of the media not emphasizing an unexpected new name for a common thing making it seem like it's new.. Ocean effect snow! (said in a deep, booming, echoing voice) Does this mean that if this (admittedly high sigma) weather pattern happened 3 weeks ago we could've had even more snow? The sea was warmer then and Manhattan air reached 11°F. Sagittarian Milky Way (talk) 16:40, 25 January 2016 (UTC)[reply]
DHeyward is correct, it's a textbook nor'easter, and the "ocean effect snow" is something I just coined to compare it against lake-effect snow, which happens on a smaller scale without needing a storm system. As for more snow, I devoutly hope not. I've been shoveling three feet of snow for the past two days and finally have it so the cars are free, we can take out the trash, get mail and let the dogs out in the back yard without losing them entirely. I think this storm system turned out to be as efficient as it could be. Normally as a nor'easter forms, the air temperature goes up as the wind starts to come from the ocean (i.e., from the northeast). Often that means that it turns to rain as the storm gets wound up. However, if there is a blocking high over the Canadian Maritimes the cold air can't be eroded by the storm and it stays cold enough to snow..Acroterion(talk) 18:00, 25 January 2016 (UTC)[reply]
See here. The prevailing explanation is that increased ocean temperatures causes more moisture to enter the atmosphere, increasing the amount of moisture available for large storm systems (hurricanes, nor'easters etc) thus making them more intense, and more frequent. --Jayron32 18:09, 25 January 2016 (UTC)[reply]
Stupid physics question (How can we see things more distant than the age of the universe?)
According to wikipedia, the age of the universe is 13.8 billion years. The origin of the universe was a single point which resulted in a big bang. The size of the universe is 91 billion light years. Nothing can go faster than the speed of light. In 13.8 billion years the size of the universe should be 13.8 light years right? Brian Everlasting (talk) 00:34, 25 January 2016 (UTC)[reply]
It's actually a very common question. The answer is that the space between large-scale structures in the universe expanded by a process called Inflation (cosmology). Dbfirs 00:38, 25 January 2016 (UTC)[reply]
This is wrong. The boundary of the visible universe is only affected by expansion since the CMBR last scattering time, around 380,000 years after the big bang. It is unrelated to inflation, which ended 10−something seconds after the big bang. -- BenRG (talk) 01:41, 25 January 2016 (UTC)[reply]
Yes, of course! Light didn't start out until after inflation stopped, so it is entirely Metric expansion of space (and that is speeding up). Dbfirs 09:56, 25 January 2016 (UTC)[reply]
(EC)see Cosmic Inflation. The part that makes it super confusing is that you would be correct IF the universe actually "big banged" INTO pre-existing space, but it didn't, SPACE it self formed along with the big bang. Vespine (talk) 00:40, 25 January 2016 (UTC)[reply]
The key point is that relativity says nothing can travel faster than the speed of light (in a vacuum) through spacetime. It says nothing about how quickly spacetime itself can move. This distinction is crucial for understanding things like inflation, but such nuance tends to be omitted from pop science descriptions, which tend to say almost-true-but-subtly-misleading things like "nothing can travel faster than light". --71.119.131.184 (talk) 00:55, 25 January 2016 (UTC)[reply]
Someone deleted my time dilation and Theory of Relativity comment, but I don't see any changes in the View History tab. Willminator (talk) 01:08, 25 January 2016 (UTC)[reply]
What I was trying to say in my deleted comment is that time is relative according to the Theory of Relativity. Gravity affects time. For example, if someone were to approach a black hole, from the observer on Earth looking up, it would look like the person has slowed down for thousands of years, but from the person's point of view, only seconds would have passed. The light of a star that's let's say, 1000 light years away from Earth doesn't necessarily have to travel 1000 years to Earth from the perspective of an observer on Earth. Willminator (talk) 01:24, 25 January 2016 (UTC)[reply]
The image on the right shows how this works geometrically. Later times are at the top. The brown line (on the left) is Earth, the yellow line (on the right) is a distant quasar, the diagonal red line is the path of light from the quasar to Earth, and the orange line is the distance to the quasar now. You can verify by counting grid lines (which represent 1 billion (light) years each) that the quasar is 28 billion light years away along the orange line though the light took only about 13 billion light years to reach us. -- BenRG (talk) 01:49, 25 January 2016 (UTC)[reply]
It's kind of funny though. I mean, the quasar is expected to be 28 billion ly away, but we don't know it didn't sprout a star drive and is coming on right behind the light ray. And in the frame of reference of the light (or someone arbitrarily close to lightspeed) no time at all has passed, and the distance is zero! (We're all just foreshortened a lot) Of the two, the frame of the lightspeed traveller is at least one we could be in, while the other distance is a spacelike estimate, so surely it is more meaningful to say it is 0 ly away than 28, right? :) Honestly though, what confuses me greatly with that diagram is what happens if something moves away from us. What exactly does it look like when a galaxy, after space cleared, has simply moved far enough away that by the time we look at it its light is almost infinitely redshifted and unable to reach us at all? (this is related to something else I don't understand, which is why the lines for us and the quasar diverge at such a sharp angle on that figure, rather than each moving down a line of "longitude" on that horn thingy. Wnt (talk) 15:51, 25 January 2016 (UTC)[reply]
Wnt, if you look more closely, you'll see that the brown and green lines for us and the quasar are each "moving down a line of "longitude" on that horn thingy". (Don't confuse the diagonal-ish red line of the light from the quasar to us with the brown line on the far left for us.) The "lines of longitude"" show static positions in space that are moving apart as time progresses "upwards" only because "space" itself is stretching.
On this scale, only something moving at a substantial fraction of light speed for a long time will show up as moving across rather than "along" the static "longitude" lines.
As for your galaxy that is "almost infinitely red-shifted", this does occur and means the galaxy is close to being beyond the Observable Universe from our point of view (as we are from its). {The poster formerly known as 87.81.230.195} 185.74.232.130 (talk) 23:04, 25 January 2016 (UTC)[reply]
The boundary of the visible universe is the cosmic microwave background. Its redshift is about 1100, large but still infinitely far from infinity. Any astronomical object we can see will have a redshift smaller than that (unless it's retreating very rapidly relative to the Hubble flow). The CMB is the boundary simply because the earlier universe was opaque to light. But it was transparent to neutrinos and gravitational waves, so I guess "visible universe" is a better name than "observable universe". -- BenRG (talk) 00:44, 27 January 2016 (UTC)[reply]
You're right that the notion of "distance now" is somewhat dubious since we don't know what has happened in the last umpteen billion years, and the spacetime interval to everything we see is zero. But, for better or worse, when astronomers are quoted in the popular press saying that an astronomical object that they just saw is X billion light years away, the orange line is what they mean.
In the diagram the Earth and quasar are both assumed to be stationary relative to the Hubble flow. This is approximately correct for Earth, and it's almost certain to be approximately correct for any distant object that's bright enough for us to see, because its speed is an average of the original speeds of the huge number of particles that make it up. If an object is moving significantly relative to the Hubble flow then its redshift is the special-relativistic redshift/blueshift of the source object relative to the Hubble flow, times the cosmological redshift, times the (small) redshift/blueshift of Earth relative to the Hubble flow. -- BenRG (talk) 00:44, 27 January 2016 (UTC)[reply]
Liquid non-Newtonian fluids?
Which non-Newtonian fluid or fluids would be considered only a liquid, not a plastic solid nor a colloid that involves liquid mixed with solid particles unless there's a colloid that is considered to be only a liquid, nothing in between? I have learned that not all fluids are liquids, but that all liquids are fluids. A couple of examples of non-Newtonian fluids are toothpaste, ice in the case of moving glaciers, ketchup, lava, pitch, and much more. They don't flow easily and consistently like water and other Newtonian liquids do. I read that pitch is said to be the world's densest liquid, but it is also considered to be a viscoelastic, solid polymer. What does that mean? Is it always a liquid? Can one look at the molecular structure of non-Newtonians fluids to determine which ones are truly liquids? Willminator (talk) 01:05, 25 January 2016 (UTC)[reply]
Is shampoo enough of a liquid for you? I don't think mine has any solid particles in it, but some might. The Kaye effect is a cool demonstration of the non-newtoniannness of shampoos and soaps, check the video refs at the bottom of our article. Also oobleck is indeed a colloid, but you can make it so that it flows nearly as easily as water. At that point, it requires a lot of force to see the shear thickening though. Check out shear thinning and shear thickening if you haven't, they discuss some additional examples and comcepts. SemanticMantis (talk) 14:45, 25 January 2016 (UTC)[reply]
Are long underwater submarine cruises harmful to human health?
AFAIK the effect of low gravity on bone density means that being in space is fundamentally harmful to humans, and no matter how fit and well-trained they are, this imposes a limit on how long astronauts can stay in orbit. Is there a similar physiological reason why long underwater cruises on a nuclear submarine would be harmful to the crew, and if so roughly how long could they stay underwater? Or would the food run out before anything else became an issue? I guess a modern sub is able to carry some gym equipment; what about sunbeds to replace exposure to sunlight? 94.12.81.251 (talk) 11:56, 25 January 2016 (UTC)[reply]
That's an interesting study - but it doesn't really tell us much because it's only run over 3 month patrols. Over 74 patrols, each with a 150 man crew (340,000 man days) they only had to pull someone out of the boats 5 times - twice were appendicitis, once for a "Chemical eye injury", once for a seizure and once for severe traumatic hand injury. I'd bet that the eye and hand injuries related to the work being done and the seizure and appendicitis cases are probably within the norms for 340,000 man hours of any other human situation.
Looking at the problems that were not sufficient to cause the crewmember to be evacuated - we have lots of other injuries - things like chest pain - and "acute opiate withdrawal". But, again, nothing that looks like problems due to being cooped up in a submarine for three months.
So from a cursory glance, there are no issues that would prevent longer missions (except of course that the submarine can't carry enough food for longer trips).
I think we'd need data from much longer trips. But a lot has to depend on monitoring and initial crew quality. The guys who are going to spend a year on the ISS get studied in minute detail before being launched up there. Submarine crews also get health checks - but I can pretty much guarantee that it's nothing like as careful as with ISS crews. That's evident from the crewmember who suffered from "opiate withdrawal"...I can't imagine that being remotely possible with ISS crews.
Looked at another way - it's hard to imagine how submariners could be worse off than the ISS crews. They don't have the gravity problems - or the lowered atmospheric pressure issues that ISS have - they have more space to move around in - and the larger crew presumably makes the mental health issues of being cooped up in a small space more manageable. Submariners get plenty of exercise and "real" food (well, more real than the ISS crew get) - and they don't generally suffer from things like solar radiation that the ISS crew have issues with. So you'd expect them to do much better.
I think we'd need longer studies and with more controlled crew selection and pre-processing before we could reasonably conclude an amount of time. SteveBaker (talk) 14:19, 25 January 2016 (UTC)[reply]
Steve remarks that it is "hard to imagine how submariners could be worse off than the ISS crews..."
Well, there is, of course, combat in submarine warfare. As unfathomable as it may seem, in this decade, for state-against-state naval warfare to occur, it is a real threat and it is one reason that large Navies still spend lots of resources to train and maintain crews and prepare for undersea warfare.
In December, I was gifted a non-fiction book, Pig Boats, about submarine warfare during World War II. It details the raw unpleasantries of the war for submarine crews. If you can imagine a way to cause health-harm to a human, the submariners had to deal with it at some time during the war. One advantage the astronauts on International Space Station have is that for the most part, nobody is actively trying to harm or destroy them.
I also don't think space weather makes the ISS rock and churn on a regular basis, as terrestrial weather does with subs. Last guy I talked to who served on a sub mentioned how some of them hated rising to periscope depth due the increase in motion sickness it could cause. Crew in a nuclear submarine probably also go longer than ISS crew without seeing the sun. This seems like a pretty serious issue, light levels are carefully studied and controlled on subs [15]. While the ISS crews may have their own problems with light, at least they can often look out the window and see the sun. Here's an interesting ref on disorders in circadian rhythms that mentions submarines [16]. SemanticMantis (talk) 15:25, 25 January 2016 (UTC)[reply]
Our OP is concerned with long underwater cruises on a nuclear submarine - they don't spend much (if any) of that time at periscope depth - so seasickness is not a significant issue. Even if seasickness were a problem - it's a short term, non-life-threatening phenomenon that would not limit the amount of time a person could spend in a submarine - so it's not relevant to answering this question.
Similarly, any likelyhood of there being combat missions for these craft has zero impact on the OP's question - which is how long you could live in one of them.
Comparisons with WWII submarines is also pretty irrelevant. A typical nuclear submarine is huge...they are not the cramped, cold, miserable places you'd imagine from seeing WWII craft. SteveBaker (talk) 16:56, 25 January 2016 (UTC)[reply]
I don't care to argue with you. But if you want to actually help OP, you could try supplying references. SemanticMantis (talk) 17:24, 25 January 2016 (UTC)[reply]
As aside, Steve, I don't think the "acute opiate withdrawal" is what you suspect. (That is, it isn't a situation where someone who got addicted to painkillers while landside, nobody noticed when he came aboard, and then he went into withdrawal when his supply ran out at sea.) The footnotes indicate that it was a patient who was prescribed opiate analgesia for pain and who abruptly stopped taking his meds without discussing it with his doctor. Yeah, it's less likely aboard the ISS, but in principle an astronaut could ignore the flight surgeon and stop taking his prescribed meds in orbit, too. TenOfAllTrades(talk) 20:50, 25 January 2016 (UTC)[reply]
Here's a few more scholarly articles on light and circadian rhythms in submarines [17][18], and one naval report [19]. SemanticMantis (talk) 17:43, 25 January 2016 (UTC)[reply]
Regarding User:SteveBaker comments above, I also fail to see how the ISS could be less detrimental to your health than a functioning nuclear submarine. Unless you are in something like the Russian submarine Kursk. It might seem counter-intuitive, but crews of nuclear submarines are even less exposed to radiation according to this source than people living above the surface. The background radiation is quite low inside a submarine. The health concerns for the ISS is not only the lack of gravity, they are also exposed to cosmic rays. Scicurious (talk) 19:46, 25 January 2016 (UTC)[reply]
IR laser line generator.
I have an idea for a commercial application needing a laser line generator. These are tiny little gadgets costing a few bucks that include a low power laser source and a lens to spread the light out like a fan over maybe 60 to 120 degrees, sealed into a cylinder a couple of centimeters long. (You see them in supermarket barcode scanners, for example).
I know that red and green laser line generators in the <5mWatt range are considered to be class 1 or 1/M laser devices - which means that they're "safe for consumer use". A line-laser is considerably safer than a regular laser pointer because the energy is spread over a wider area, hence class 1 or 1/M rather than class 2 like most laser pointers.
But I'm considering switching from a red light laser to an IR line-laser of identical power and beam spread. I realize that IR lasers are invisible - so there is a risk of someone staring into the thing without knowing it's there, they don't invoke the blink reflex or close down the iris.
Trouble is, I can't figure which class these IR devices belong to and there is no indication on the manufacturer's web site to tell me.
Does anyone know the guidelines about these classes of device? Does the class get better if I limit the power to 3mW or even 1mW?
I think you'll need to get a copy of ANSIZ136.1 to rigorously answer this question. It does not seem to be freely available. Laser_Institute_of_America, the official secretariat of ANSI in this matter, will sell you a print or electronic copy. Here [20] is the TOC and index. Here [21] is a comparison of the 2014 standard compared to previous versions. SemanticMantis (talk) 17:34, 25 January 2016 (UTC)[reply]
The way I learned it in school, every non-visible laser was automatically treated as if it were a Class IV laser. However, if you dig very deeply into, say, OSHA standards, they do not (for the most part) actually distinguish between different classes of laser when specifying workplace safety requirements. As SemanticMantis correctly pointed out, the ISO, ANSI, and IEC technical specifications that define commonly-used laser classification terminology are neither free nor zero-cost.
Invisible lasers are inherently more dangerous: you won't even notice when they malfunction, or when they reflect specularly off a distant object, and so on.
Classification based on continuous wave power at various wavelength.
I can't speak to the accuracy, but laser safety does have charts regarding safe exposure and classification at near-infrared wavelengths. One of the graphs, reproduced at right, suggests that near-infrared wavelengths would be considered Class 1 ("safe under all conditions of normal use") at power levels less than around 0.5 mW and class 3R (or worse) at higher power levels indicating at least some risk of eye injury. If you are definitely going to work with such lasers, I would strongly recommend you verify such safety information with reputable third parties. Dragons flight (talk) 12:27, 26 January 2016 (UTC)[reply]
0.5mW is really low. I've only found cheap 'near' IR line lasers at 1.0mW - but that's spread out over around 90 degrees of 'line'. I wonder whether the classification system would be OK with me physically limiting how close someone could get their eye to the laser such that no more than (say) 1/10th of the entire line could impinge on their eye? Assuming that the light is spread out evenly, that would limit the practical exposure to 0.1mW - which ought to be really safe.
The trouble with "reputable third parties" is that they want to charge a lot of money for their services! I'll certainly go that route before making a final product - but if it's clear that an IR line-laser a non-starter then I'd rather not fork over the cash! SteveBaker (talk) 15:08, 26 January 2016 (UTC)[reply]
One option would be to move to longer wavelengths. I was reading the graph at ~800 nm, but if you can move to short-IR at say 1500 nm, you can apparently go to 10 mW at Class 1. Not sure what wavelengths of lasers are available though. As you say, there is probably a fair argument that a line source is much less dangerous than a point source, but I'm not sure how they officially consider such details. Dragons flight (talk) 15:40, 26 January 2016 (UTC)[reply]
The key to safety with lasers - or any other energetic item - is not whether the device is safe when used correctly. It's about ensuring high confidence that the product is idiot-proof, accident-proof, and so forth. Spreading laser energy using a lens or optic does truthfully reduce the hazard - as long as the optic is correctly operating. If the laser is only eye-safe when the beam is spread into a large angular pattern, then what would happen if the device is dropped or misaligned, and the same laser light energy no longer travels through the optic? Now the device has become unsafe.
This is why lasers are classified for safety, and fully-assembled optical systems are not: the beam-spreader may reduce hazard, but the laser itself is still a Class IV, (or whatever).
And when your laser light is invisible - you will not see it when the beam escapes from its designed optical path.
Steve runs a small business - he doesn't have a corporate training department to provide a mandatory Laser Safety class; he doesn't have some weaselly guy from Health and Safety department running around telling him what he may and may not do; he doesn't have a collared shirt from the legal department telling him how to reduce corporate liability or ensure compliance in every municipality where his business might be construed to operate; and Steve is (as evidenced by his comments) interested in cutting costs. Steve, I really try to avoid interjecting pure, unreference-able advice when I contribute to the reference desk, but here's some free advice from a person who has worked with lasers; err on the side of caution. Do not try to manufacture or sell or use an invisible laser. If you want to play with something safer, try removing the blade-guard from a circular saw, or dumping the charge out of shotgun shells, or generally anything else where you can see and avoid the hazard.
On more than one occasion, I have noticed little bugs in boxes of uncooked pasta. I see them as soon as I open an otherwise unopened box. Or when I put the pasta in boiling water, I see the little bugs rise to the top. Needless to say, it's disgusting. Where did they come from? How did they get there? And how do I prevent this in the future? I have done a Google search and got a lot of mixed and contradictory results. Help! Thanks. 2602:252:D13:6D70:6441:F28D:D981:B287 (talk) 18:01, 25 January 2016 (UTC)[reply]
What do they look like? All kinds of pests might infest a pantry, and there may be some slight differences in how to treat. A common one is the pantry moth AKA Indian mealmoth. Does that look like the right bug? Another common pantry pest is the flour beetle. One thing to look into is whether you are buying contaminated goods or if the pests are getting in to your food at your house. If it's the former, buy different things. If it's the latter, there are steps you can take. Here are some reliable sources for how to treat and prevent pantry pests: UC Davis [22], Clemson [23], Utah State Extension [24]. Transferring things like pasta to airtight containers is a good first step. SemanticMantis (talk) 18:08, 25 January 2016 (UTC)[reply]
Hard to describe. They are so tiny, they are about the size of a pencil-point tip. Perhaps it is that pantry moth AKA Indian mealmoth that you linked above? (I assume the photos in that link are magnified many, many times over?) I have read that they are already in the pasta (as eggs? or larvae?) and that they then hatch after they come into the house. In other words, they are already in the box when I buy it at the store. Help! Thanks! 2602:252:D13:6D70:6441:F28D:D981:B287 (talk) 18:19, 25 January 2016 (UTC)[reply]
Don't sound like it. You should be able to see the light coloured segmented larvae (grub) (which may look slightly similar to a Maggot) if they were Indian mealmoths. By the time they are fully grown, the size may be about the size of a broken of pencil tip i.e. perhaps 5 mm-10mm long, not simply the point. You'll also see their waste (the threads). And if you've been having the problem for a while it's likely you'll see the months around your house. I think it's more likely to be some sort of Flour beetle from your description. Or maybe a Wheat weevil or some variety of Oryzaephilus or something like that. Nil Einne (talk) 18:47, 25 January 2016 (UTC)[reply]
(EC) Note that if they are Indian mealmoths, you should transfer even opened containers since they are great at piercing plastic bags. Even then, you may find they make their way into containers which seem airtight. (It's possible the food or container was already infested with eggs but I'm not convinced it always was. There's also the fact that sometimes you see signs of the infestation, but no dead larvae or moths despite the product not being opened in a while.) Freezing generally kills the eggs and some people recommend it even if you're planning to throw out the food, particularly if your rubbish won't be picked up for a while. (If you're home composting you definitely want to freeze. Indian mealmoths are not something even helping your composting.) All these combined mean even if it only a localised infestation, it can be quite difficult to get rid of and may require a fair amount of stuff to be thrown out. Nil Einne (talk) 18:28, 25 January 2016 (UTC)[reply]
I don't mind throwing the old boxes out. No problem. But what do I do with the new boxes? The ones that I bring home from the store? Thanks. 2602:252:D13:6D70:186C:D475:39EF:E0EC (talk) 18:45, 25 January 2016 (UTC)[reply]
Did you read my three last links above? They tell you very clearly how to deal with pantry pests. The short version is: buy food without pests, and store food properly. While it can happen that goods are infested before you buy them, things are more likely colonizing the food in your pantry. Invest in some airtight containers, and inspect your food as soon as you get it home. If you detect pests in the food when you first get it, return it to the store and complain. SemanticMantis (talk) 18:49, 25 January 2016 (UTC)[reply]
(EC) I was mostly referring to Indian mealmoths. But the point is to remove the infestation. If you've successfully removed the infestation (it will take a few weeks or months to be sure), there shouldn't really be anything much to do other than taking resonable precautions like storing food in airtight containers, keeping an eye out for reinfestation and not buying too much food (i.e. using the food fairly fast). As was mentioned by SemanticMantis, if the food is infested at point of purchase, it's probably better to simply buy food that isn't infested. If you really want to treat infested food, I suspect freezing will work for most insect pests (particularly multicyclic freezing). Nil Einne (talk) 18:53, 25 January 2016 (UTC)[reply]
We've dealt with them by putting grain products into metal bins as soon as they come in from the store, and by using pantry moth traps (available at your favorite home improvement store) that use a pheromone lure to a sticky trap. They also help to monitor whether you've got a problem. Use cans and traps for a couple of life cycles and you should be free of them. Acroterion(talk) 18:55, 25 January 2016 (UTC)[reply]
Thanks for the indent and sorry for just dumping the link there. I couldn't reach they keyboard because I was snuggled up under the blanked with only a mouse because it's like -54 Kelvin here. By the way, consider zipping over to the Home-stored product entomology talk page about that article and it's big 5 pests (more than that, me thinks!). Anna Frodesiak (talk) 00:08, 26 January 2016 (UTC)[reply]
Thanks. If I buy a box of pasta, can I just throw it in the freezer? If so, would I throw it in the freezer as is (in the original box)? Or put the contents of the box in some other container? And, if I freeze it, what do I need to do when I want to cook it? Thaw it? Defrost it? Or just cook it right from the frozen state? Thanks! 2602:252:D13:6D70:186C:D475:39EF:E0EC (talk) 19:23, 25 January 2016 (UTC)[reply]
I think you can freeze it in the original container and toss it right in the boiling water from there. If there's any left, you might want to seal the closed package in a plastic bag, to prevent freezer odors from being absorbed. You might use the plastic bag right from the beginning, too, as pasta boxes don't seem to be properly sealed to me (which is probably how bugs keep getting in). You might try another grocery store and another brand of pasta, as one or the other obviously has an insect problem. StuRat (talk) 19:51, 25 January 2016 (UTC)[reply]
Yeah, the solution to bugs in your pasta is not freezing all your pasta forever. It's buying pasta with better quality assurance and using proper storage... SemanticMantis (talk) 20:17, 25 January 2016 (UTC)[reply]
I don't see the need to freeze indefinitely. The point of freezing is kill the eggs. If you don't have an existing infestation and practice decent vigilance and do your best to, you'll hopefully not get another one if you kill eggs before an infestation can take hold. (There is a risk that freezing won't kill all eggs particularly if the food has a lot of them and you are buying a lot of food that is infested. It's also likely some species have eggs that are hardy enough to survive freezing, or even cyclic freezing.) I do agree that this doesn't seem the smartest solution as opposed to just avoiding products that are infested. Nil Einne (talk) 13:34, 26 January 2016 (UTC)[reply]
A few people have said that I should buy food that is not infested. That is obvious. But, how do I know that when I am at the store? I don't see or notice these bugs until after I get home and open the box and start to cook. So, at the store, how would I have seen/noticed this? Obviously, one does not open up the box of pasta in the store. It sits at home until the day I decide to use it. 2602:252:D13:6D70:186C:D475:39EF:E0EC (talk) 20:56, 25 January 2016 (UTC)[reply]
I suggest you start opening them when you get home, to determine if they have bugs, because, if they do, those bugs might infest other items in your kitchen, like cereal boxes. You may already have an infestation problem, in which case you would have to take action to clear that up. Another alternative, once you've found the pasta to be clean, is to store it in glass or tin containers, which, unlike those paper boxes, seal tightly enough to keep bugs out. StuRat (talk) 21:04, 25 January 2016 (UTC)[reply]
As already mentioned, you should be storing your food in airtight hard containers if you are having problems. It's ideal if you do this from the getgo since some insects can pentetrate the plastic bags. If you open your food and find it is already infested, and return it to the store. If this happens often or they refuse to accept returns purchase the same (or nearly the same) day when they are clearly defective and unless you're giving them older items must have been defective when purchased you should do what's already been suggested and shop somewhere else. (If they do accept returns and it happens often and you still want to shop, I guess they'll probably know they have a problem and so keep letting you make returns despite the fact you're always doing it. If they do start to make problems, I guess you could say you'll open it in front of the staff.) Nil Einne (talk) 13:31, 26 January 2016 (UTC)[reply]
Storing non-perishables in your refrigerator should be a good test. If it still has bugs, they most likely came from the store or the manufacturer, not from your hone. ←Baseball BugsWhat's up, Doc?carrots→ 16:34, 26 January 2016 (UTC)[reply]
My refs above
Sorry, it looks like I've inserted some references where they shouldn't be, and I can't seem to delete them. Can anybody more experienced with wiki editing remove those 3 links please? Thanks Mike Dhu (talk) 21:02, 25 January 2016 (UTC)[reply]
I changed them to bare urls, so that they don't appear at the bottom of the page - I hope that's what you wanted. Mikenorton (talk) 21:08, 25 January 2016 (UTC)[reply]
Great, thank you, I need to learn more about how to edit wikipedia, I must have selected the wrong tag for the references. Sorry, I'll stick to sandbox for a while :-/ Mike Dhu (talk) 21:16, 25 January 2016 (UTC)[reply]
There's a way to embed references within a section on a talk page, but the exact syntax is not coming to mind just now. ←Baseball BugsWhat's up, Doc?carrots→ 21:30, 25 January 2016 (UTC)[reply]
Yes, one of those previous edits, before Mikenorton kindly corrected my mistake, was my reply to a question where I wanted the references to appear, but they were appearing at the bottom of the ref desk. I used the 'ref' tag instead of square brackets, but realise now they are used for different purposes. I should probably post the rest of this reply as a question on the computing ref desk but I'll ask here first out of courtesy as this is where I made the mistake. I'll be spending a bit of time in sandbox now, but would it be possible to change the tooltips to give more information? Whenever I hover over any wiki markup it just displays a tooltip that I should click on it to insert it, without explaining specifically what the markup is for. I appreciate that for those of you who have spent a bit of time editing wikipedia it's second nature to know what tags to use, but more info on tooltips would make it easier for newcomers. Thanks Mike Dhu (talk) 00:22, 26 January 2016 (UTC)[reply]
There's no need for self-deprecation; in many ways, the problem is with this page and not anything you did "wrong". Considering that we're ostensibly here to supply references, we're not actually well set up to provide them in the same manner that articles do. Matt Deres (talk) 15:50, 26 January 2016 (UTC)[reply]
I didn't think I was being self-deprecating, just acknowledging that I made a mistake while I'm still learning how to edit wikipedia, but thank you. It would be nice to have more info from the tooltips though, so I'll post a question on the computing ref desk about that. Mike Dhu (talk) 22:07, 26 January 2016 (UTC)[reply]
January 26
Atmosphere of Venus / compressing C5O10N2
I was musing over a Venus terraform in a very crude way, considering what the prevalences in a 92 bar atmosphere are relative to Earth:
CO2: 8878% vs 0.040%
CO: 0.16% vs ~0
N2: 322% vs 78.084%
Ar: 0.64% vs 0.93%
H20: 0.18% vs 0.001%-5%
He: 0.011% vs 0.0005% (waaaat?)
Ne: 0.064% vs 0.0018%
SO2: 1.38% vs ~0
I get that in order to make Venus atmosphere Earthlike, you basically have to dump 364 pounds of C, 970 pounds of O, 36 pounds of N and a mere 0.1 pounds of S onto every square inch of the planet's surface - or beneath it. Ignoring the S, which can clearly be made a solid but seems too small a component to figure into a bulk formula, that's an empirical formula of C5O10N2. Now we saw in a thread above that even bulk CO2 can be pressurized into an extended solid, but is there any way to predict what this composition would turn into, at what pressure? For example, I'm thinking you might get two NO2 groups on a C5O6 extended structure (almost a polyketone, though adjacent ketones are high-energy and disfavored) ... but I certainly don't know that. It seems empirically like a doable experiment, but has anyone done it? (yes, I realize that this is nearly 1 million times harder than fixing global warming, possibly using similar carbon sequestration technology, without a local infrastructure, and so it is not going to be done by any normal means we know of today... and the planet is still extremely dry)
Another question: why so much helium? I thought the conventional wisdom was that light gasses are lost, but if you sequester away the other stuff there's like 200 times more helium on Venus than here - even though the argon level is lower. and there's also 60 times more neon. I thought a noble gas was a noble gas... There might be an answer at [25] but I didn't have access, and can't riddle it out by the abstract. Wnt (talk) 17:27, 26 January 2016 (UTC)[reply]
The thermosphere of Venus is much colder than that of Earth. Therefore the losses of light gases are smaller. Ruslik_Zero 20:37, 26 January 2016 (UTC)[reply]
Research article query
According to the article found at [26], figure 2 implies that as the hydrogen content in chromium approaches nothing, the FCC and HCP crystal structures of chromium become stable at ambient pressure. This is a problem, because it is know for a fact that the BCC is the solely stable structure at ambient pressure and temperature. How does one reconcile this implied inconsistency? Plasmic Physics (talk) 20:42, 26 January 2016 (UTC)[reply]
I don't know about "known as a fact" (or crystal phases of chromium hydride, at that). In general, science is always preliminary. But in this case, the system is at 150°C, which certainly is not "ambient temperature". --Stephan Schulz (talk) 22:12, 26 January 2016 (UTC)[reply]
Chromium with zero percent hydrogen can hardly be considered as chromium hydride, can it? Looking at the pressure-temperature phase diagram of chromium, it should remain as BCC up to its melting point. So, the system being at 150 degrees should not matter. Plasmic Physics (talk) 22:54, 26 January 2016 (UTC)[reply]
Earliest predictions of man on moon in 60s?
May 25, 1961 President Kennedy announced the US goal to send men to the moon and return, 'by the end of the decade'. Are there records of earlier predictions by scientists, policy makers or governments (not looking for the 'Jules Verne' long literary history), that men could land on the moon in the 1960s or by when? I'm interested in finding the first informed, professional prediction that proved correct - men walking on the moon before the end of the 1960s. Thanks if you can point to a link or citation.
Extensive predictions, varying in accuracy and credibility from fringe lunatics to public statements by esteemed scientists, major movers and decision-makers! I have a stack of moon books at home written in the 1940s and 1950s; they make for great historical reading. If you'd like a complete listing, I can provide titles and authors.
Perhaps the first place to start is our article on Wernher von Braun:
"In 1930, von Braun attended a presentation given by Auguste Piccard. After the talk the young student approached the famous pioneer of high-altitude balloon flight, and stated to him: "You know, I plan on traveling to the Moon at some time." Piccard is said to have responded with encouraging words."
By the mid-1950s, the accuracy of the mission-statement was becoming very concrete and there are hundreds of scientific publications that aptly describe how a manned moon mission would probably look.
The reason that Mr. Kennedy's statement was so important was that he had the power to finance the program.
This 1979 documentary by James Burke, The Other Side of the Moon, is spectacular. He overviews the political clime, including interviews with several scientists and program managers. Among the key statements (somewhere probably around half an hour into the documentary) is a description of how they managed to get Mr. Kennedy to make a statement: it had been decided that it would be politically expedient for Vice President Johnson to formally advise the president in writing that a moon mission would be possible, and that it would be politically expedient for the President to proceed to order a study, and eventually make a formal public statement. The discussions that led to that point were quite extensive.
See Moon in fiction, which lists many previous stories of human landings on the moon. Use your own judgment as to how realistic any of the twentieth-century stories were. Robert McClenon (talk) 23:37, 26 January 2016 (UTC)[reply]
Can a man's epididymis grow back if *all* of it is removed?
I don't think so. Organs generally don't regenerate. Semi-exceptions: liver and brain. Why are you asking? Are you thinking of something like a vasectomy spontaneously reversing, which can happen? If so, that involves the vas deferens, not the epididymis. --71.119.131.184 (talk) 00:26, 27 January 2016 (UTC)[reply]
Why exactly can the vas deferens grow back but not the epididymis, though? Futurist110 (talk) 02:34, 27 January 2016 (UTC)[reply]
Indeed, if one tube/duct can grow back, then why exactly can't another tube/duct likewise grow back? Futurist110 (talk) 02:36, 27 January 2016 (UTC)[reply]
Good question. It doesn't really "grow back" in the sense of sprouting a new one from scratch. Exact vasectomy methods can vary a little (see the article), but in general the vas deferens is severed. Sometimes a portion is removed, but sometimes it's just cut, and the cut segments closed off with surgical clips or something along those lines. So, you can get minor tissue growth that winds up reconnecting the segments. Some additional procedures, like forming a tissue barrier between the vas deferens segments, have been tried to reduce the likelihood of spontaneous reversal. In general, the less differentiated a tissue is, the easier it is for it to regenerate. The vas deferens are fairly simple muscular tubes, in contrast to the epididymis and testes, which are specialized organs, so it's not surprising that you can get some regrowth of the vas deferens. --71.119.131.184 (talk) 02:45, 27 January 2016 (UTC)[reply]
Another exception is skin, which grows just fine, if given enough time (like when you gain weight). But, if you try to grow it too quickly, you get stretch marks and scars.StuRat (talk) 00:29, 27 January 2016 (UTC) [reply]
U.S. currency subjected to microwaves
See HERE Is there any validity to this? Hard to filter out the nonsense/conspiracies. If so what is the mechanism of action? 199.19.248.82 (talk) 02:07, 27 January 2016 (UTC)[reply]
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