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July 1

Malaria

Does malaria exist in Japan since its common in Asia? Clover345 (talk) 07:40, 1 July 2013 (UTC)[reply]

statement by banned user retained only because it was answered

The following discussion has been closed. Please do not modify it.

No. Malaria does not occur in Japan. Malaria is spread by mosquitoes and requires a hot tropical climate that supports mosquitoes. Malaria is mainly a problem in tropical jungles that combine high temperatures with plenty of water for mosqitoe larvae to grow in. Japan is too far north of the equator and is thus not a hot tropical jungle region. Malaria cases occured in Japan when soldiers returning from World War 2, having caught it in jungle areas, but as there was no means to efficently spread the disease, once the soldiers recovered, there was no more malaria. See http://idsc.nih.go.jp/iasr/18/213/tpc213.html — Preceding unsigned comment added by 124.178.183.4 (talk) 11:21, 1 July 2013 (UTC) statement by banned user wickwack[reply]

Thats so gabbled and inaccurate that it does not start to answer the OP's question. There is no indigenous malaria in Japan anymore because the intermediate host (i.e., humans) infected by malaria are too few now to sustain a reservoir of this disease (due to modern anti -malarial drugs). The climate of southern Japan suits the vector (mosquitos) very nicely (as your ankles will witness in the evenings when they come out to bite). --Aspro (talk) 12:01, 1 July 2013 (UTC)[reply]

Indeed. Malaria was also endemic to Britain until the 1950s, when land drainage and modern healthcare eradicated it. Britain's climate is similar to Japan's, and the assertion that Malaria "requires a hot tropical climate" is nonsense. ref. -- Finlay McWalterჷTalk 13:26, 1 July 2013 (UTC)[reply]

Regarding malaria in Britain, our article on the history of malaria says "Malaria was once common in most of Europe and North America, where it is now for all purposes non-existent ... in the coastal marshes of England, mortality from "marsh fever" or "tertian ague" ("the ague" from Latin "febris acuta") was comparable to that in sub-Saharan Africa today". Gandalf61 (talk) 15:17, 1 July 2013 (UTC)[reply]

Yep, the climate is suitable. According to http://idsc.nih.go.jp/iasr/18/213/tpc213.html there were estimated to be "...20,000 cases of indigenous malaria per annum before the World War II" in Japan. Of course, the anti-malarial drugs and mosquito controls were sufficient to end its malaria problem. If Japan is anything like North Carolina, there have always been enormous numbers of them buzzing biting insects to deal with (we have a particularly large land area and plenty of swamps!). Targeted killing works though. --Modocc (talk) 11:48, 2 July 2013 (UTC)[reply]

There are conflicting accounts regarding Malaria's history in Japan, but the mosquito Anopheles sinensis found in Japan is known to be a vector for Plasmodium vivax (it is apparently refractory to P. falciparum). Malaria is found in many non-tropical areas; for example, it was endemic in much of the United States at one time. -- Scray (talk) 11:38, 1 July 2013 (UTC)[reply]

There is a meta-discussion regarding the dynamic IP address at the reference desk talkpage here http://en.wikipedia.org/wiki/Wikipedia_talk:Reference_desk/Science#WickWack_is_back. --Modocc (talk) 04:02, 4 July 2013 (UTC)[reply]

How would certain wikipedians do in the World Quizzing Championship?

Really, some of you show an incredible depth of general knowledge when answering questions... I wonder how some of you would do as quizzers in the World Quizzing Championship? I'm posting this here because I was hoping for a scientific answer. Do these quizzers really have an excellent general knowledge like some of you do, or do they have a different type of brain that is trained to retain bits of trivia? On this matter, it seems to me that some of their quizzing questions are a bit contrived and generally limited to western knowledge rather than true global knowledge... I wonder how these so-called eggheads would do given a random sampling of wikipedia's "did you know" questions? Sandman30s (talk) 14:08, 1 July 2013 (UTC)[reply]

Not sure. I participated in academic competitions (in the U.S. called Quiz bowl) of various forms throughout HS and College, such as Granite State Challenge, Academic Competition Federation, College Bowl, National Academic Quiz Tournaments, etc. I have a few trophies. --Jayron32 14:33, 1 July 2013 (UTC)[reply]

I suspect that most Ref Desk denizens would fare no better than an average person (although there are exceptions). What we do (or at least, what we're supposed to do) is to use Wikipedia and other online information to find references in order to answer questions - and according to the US WQC site: "The World Quizzing Championship takes the form of a written quiz taken by individuals using no reference materials". Kinda the opposite of what we do. Being good at answering RefDesk questions really requires a broad - but very approximate - base of knowledge, combined with being clever at using search engines in creative ways. SteveBaker (talk) 14:34, 1 July 2013 (UTC)[reply]

I also think it's quite likely that many of the regulars would object on principle to supporting an organization that thinks a "quizzer" is someone who answers questions, and "quizzing" is the process of answering questions. See quiz. Tevildo (talk) 19:20, 1 July 2013 (UTC)[reply]

The average person believes a large number of things that simply aren't true and actually knows very little geography, history, or science. Personally, I would like to imagine that the average Ref Desk responder is at least a little better informed than the average person on the street. At the very least most of the people here at least have some interest in thumbing through the fascinating bits of our encyclopedia, and might just remember some of what they read. Dragons flight (talk) 20:49, 1 July 2013 (UTC)[reply]

For SteveBaker, I would add from my experience that answering questions on the ref desk seems to be about adopting the most pedantic interpretation of a question that you can, and giving a silly answer to it. I've seen this quite a lot. As far as this question goes, I think most brainiacs would find it very easy to answer the "did you know?" questions: they would just say "yes" to all of them. And if that's not pedantic, I don't know what would be. As for the question, Australian quiz champ Vincent Smith just said to read widely. It means you would usually have a very good general knowledge. It would not necessarily be deep, but you would be more than just a fact machine. IBE (talk) 09:20, 2 July 2013 (UTC)[reply]

I agree that there is an unfortunate tendency to do that. It's much easier to produce a stupidly pedantic/silly answer than to figure out the true answer and reply properly. We try to discourage this kind of bad behavior and to "weed out" the individuals involved - however, this is "The Encyclopedia That Anyone Can Edit" - and unless these people are actively breaking our rules, it's hard to ban the useless ones. Also, there is a problem that there can sometimes be a thin line between a stupid answer and a decent one. Often our OP's need to be a little patient in order to get the answer they need! SteveBaker (talk) 14:39, 2 July 2013 (UTC)[reply]

Version:1.0 StartHTML:0000000167 EndHTML:0000001417 StartFragment:0000000484 EndFragment:0000001401

Comment: I think some silly answers are posted by people who take after Marvin the Paranoid Android who has a brain the size of a planet but is never given the chance to use it. They may well 'feel' (as opposed to think) that some eloquent posters of questions could get far quicker -all most instantaneous- answers by taking this advice (?):[[1]]. In my experience for example, a good librarian is one that not only finds your answer but shows you how you can navigate your own way to answering your next question. Of course, if a poster to a question doesn’t know how to navigate, using what s\he already knows (and to cross reference as a check, that the info is sound) – then their options are limited and thus we are here to help. Well, some of us. ---Aspro (talk) 19:57, 2 July 2013 (UTC)[reply]

Two questions about the blood donation or blood test

Hi, I would like to ask two questions about the blood donation or blood test: The first question is: How long after donating blood or blood test that takes the blood to produce the same amount of the blood out of out from the body as I understand it is a process which takes time to create blood cells in the bone marrow and does not ends up by drinking liquids ...

And the second question is: Is there is any advantage physiologically in a blood test? (Note, I'm not talking about the importance of the tests themselves but if there is any _ benefits in taking blood out from the body in the case of an ordinary person who is not suffering from polycythemia - Multiple in taking blood). Thank you. מוטיבציה (talk) 15:35, 1 July 2013 (UTC)[reply]

I don't have an answer for the first question, but for the second question, our article on bloodletting says that it is not considered beneficial except for a few specific conditions, most notably iron overload. Looie496 (talk) 17:46, 1 July 2013 (UTC)[reply]

According to the UK blood service "it takes several weeks for all the red cells to be replaced [after a donation]". Platelets and white cells are replaced "over the next few days". The minimum gap between donations in the UK is currently 12 weeks for men and 16 weeks for women, but for donations by apheresis (where the red cells are returned to the body during the donation) the gap is less (a month when I used to do it, though that was quite a while ago). AndrewWTaylor (talk) 17:59, 1 July 2013 (UTC)[reply]

Note that the amount of blood taken in a blood test is "only a small amount" [2] whereas a blood donation (in the UK at least) is 470 ml [3] or 0.83 of an Imperial pint, plus various samples that are tested for HIV, hepatitis and so on. Alansplodge (talk) 20:36, 1 July 2013 (UTC)[reply]

what is the purpose of the breathing from mouth to mouth in CPR?

What is the purpose of the breathing in the life support CPR? I heard that the goal of the mouth among 30 massage of the heart is actually to stimulate the respiratory system or the control area in the brain responsible for breathing, by carbon dioxide (CO2). Until then, I thought that the goal is just to put oxygen into the mouth of the unconscious person. I'd love to sort the issue. Thanks מוטיבציה (talk) 17:40, 1 July 2013 (UTC)[reply]

The purpose is to move oxygen into the lungs of the unconscious person, if they are not breathing. --Demiurge1000 (talk) 18:03, 1 July 2013 (UTC)[reply]

I agree with Demiurge1000. The idea of stimulating respiration with CO2 is contradicted by the protocols for more advanced rescuers, who always switch to pure O2 as soon as the equipment can be set up. Jc3s5h (talk) 18:07, 1 July 2013 (UTC)[reply]

Cardiopulmonary resuscitation says: "Current recommendations place emphasis on high-quality chest compressions over artificial respiration; a simplified CPR method involving chest compressions only is recommended for untrained rescuers", confirming what I've been told by people who've been on First Aid courses recently. AndrewWTaylor (talk) 18:14, 1 July 2013 (UTC)[reply]

Does it mean that whwn we put oxigen into the mouth of the unconscious person, and then we compress his chest, the oxigen come in into the blood? מוטיבציה (talk) 18:46, 1 July 2013 (UTC)[reply]

Blood oxygenation doesn't work that way. Oxygen diffuses from the lungs (not mouth) passively (not caused by other actions) into the blood. Circulation just circulates the oxygenated blood to other parts of the body. You might want to read our articles about and breathing and the circulatory system to make sure you understand these basic features. DMacks (talk) 18:54, 1 July 2013 (UTC)[reply]

Of course, maybe I didn't explain myself properly, but it's clear for me the way of the air/oxigen come in into the blood through the lungs, my question was about the CPR specificly.I would like to know if the air we put into the mouth of unconcious person, it's come in into the blood by our combination of the chest compression and breathing. Note, I don't mean about the reserve oxigen in the blood that we move in the body by our compressions, I mean about the NEW air we breath from mouth to mouth or even by oxygen bottle. it means that I would like to know if the mechanical act that we do, makes the same act when the heart work by itself. thank you for the links. מוטיבציה (talk) 20:07, 1 July 2013 (UTC)[reply]

Oxygen gets into the bloodstream through the cell membranes of the alveoli. Mechanically breathing for someone (mouth to mouth resuscitation) is meant to ensure that fresh air gets into the lungs so that oxygenation of the blood can occur. The chest compressions are to do with ensuring blood circulation, not an attempt to squash the lungs to reproduce breathing. If you think about it, you will see that the speed of chest compression is nearer to the speed of the heartbeat than to the pace of breathing. --TammyMoet (talk) 20:38, 1 July 2013 (UTC)[reply]

So, I can understand that you say that the oxygen (of the breating) get into the bloodstream by the time of the CPR. Do I understand well? מוטיבציה (talk) 21:54, 1 July 2013 (UTC)[reply]

You may or may not understand well, but I do not understand you well. If the blood (around the lungs or otherwise) is already well oxygenated "by the time of the CPR" (which appears to mean "before the CPR begins"), then only chest compressions are necessary, and artificial respiration (mouth to mouth) is not.

This is incorrect. Oxygen is still required by the body during chest compressions.217.158.236.14 (talk) 11:13, 2 July 2013 (UTC)[reply]

Or what is it that you mean? The purpose of the artificial respiration (mouth to mouth) is to increase the oxygen concentration in the lungs, with the result that more oxygen is absorbed into the blood around the lungs. The purpose of the chest compressions is to move that blood (and other blood) around the body, including in particular to the brain. --Demiurge1000 (talk) 23:43, 1 July 2013 (UTC)[reply]

Modern first-aid training for the common person uses only chest compressions. The compression of the lungs forces air in and out as well as compresses the heart muscle. 217.158.236.14 (talk) 11:13, 2 July 2013 (UTC)[reply]

^{[citation needed]} If you get proper training (and not just through the Internet, you'll learn to perform mouth-to-mouth. Chest compressions only is only recommeneded for the inept. OsmanRF34 (talk) 18:03, 2 July 2013 (UTC)[reply]

Incorrect, dangerous, and insulting statement - if you get "proper" training, you'll learn to use a ventilation device such as a pocket mask/BVM. No-where recommends mouth to mouth anymore. You'll also learn that for anyone who doesn't do it regularly enough to retain the skill, compression only CPR is recommended, and according to the evidence just as useful (if not more useful) in the hands of a lay responder. So it's not "for the inept", but for the evidence based and competent. Nickopotamus (talk) 3:47 pm, Today (UTC−4)

E 85 (Ethanol vehicles)

Can an E-85 vehicle be run just on gasoline? 190.140.206.17 (talk) 20:01, 1 July 2013 (UTC)[reply]

Yes. A few points of clarification: E-85 is the fuel, not the vehicle. The vehicle is called a flexible-fuel vehicle, and our article says they run on pure gasoline. Note that whether "normal" cars should use E-85 is contentious, and described at E-85#Corrosion_debate . I am not aware of any production vehicle that is designed to only run on E-85 or ethanol. SemanticMantis (talk) 20:30, 1 July 2013 (UTC)[reply]

E85 means 85% ethanol and 15% gasoline. Once running, most standard internal combustion engines will run just fine on E85...for a while! The problem is that the ethanol is quite corrosive and can dissolve some plastics and rubbers found in seals and hoses. As the percentage of ethanol increases, some cars become harder to start - but most run OK once you do get them started. Flex-fuel vehicles are basically made with the appropriate plastics and metals to resist this corrosion and have engine management computers that handle the startup thing properly.

My 1963 Mini Cooper has rubber parts that even E10 fuel (which is standard in most of the USA) will eventually corrode/dissolve - but modern cars have synthetic materials that protect them at least to that degree.

In Brazil, most people run their cars on 100% ethanol - using a small amount of gasoline in a separate tank just to get the car started. In theory, they shouldn't convert standard vehicles to do that - but they do, and they get away with it - noting that they have to replace some parts more often than they otherwise would - but if you're driving an old junker, the thing will probably die for other reasons long before ethanol corrosion becomes an issue.

SteveBaker (talk) 14:33, 2 July 2013 (UTC)[reply]

You are not quite right about Brazil. Indeed they use flexible-fuel vehicles that run on a combination of gasoline (E20-E25 blend) and hydrous ethanol (E100). OsmanRF34 (talk) 17:52, 2 July 2013 (UTC)[reply]

Also, I believe the air/fuel ratio for ideal combustion is different with gasoline and E85. It may still run at the other ratio, but it won't be very efficient. StuRat (talk) 03:25, 3 July 2013 (UTC)[reply]

Flex fuel vehicles automatically adjust to keep the mixtures correct according to our article. Rmhermen (talk) 03:59, 3 July 2013 (UTC)[reply]

Many older cars is Brazil are not flex-fuel and were specifically designed to run on ethanol. These cars will not run well on gasoline. The main problem is not the difference in air to fuel ratio which can easily be adjusted. The problem is the different compression ratio of ethanol based engines which will lead to engine knocking if gasoline is used. Dauto (talk) 17:54, 4 July 2013 (UTC)[reply]

July 2

Mars will definitely survive or it is possible to get eaten by sun

I am trying to find an outside source say Mars may get swallowed up by sun in 6-7 billion years [4] I can't remember every source I visited in the history stating Mars may even get eaten up by sun. Is the best answer to state Mars will definitely not get eaten by sun in 6-7 billion years or best answer is since Mars is further away from sun than Earth is it stands at better chance surviving than Earth? I don't know who said sun's expansion can reach 2 AU. Maybe our diagram is somebody made mistake, because I can't find other source said 2 AU?I am guessing somebody on Wikipedia made mistake--69.233.254.115 (talk) 02:04, 2 July 2013 (UTC)[reply]

This is what Wikipedia has to say on the subject. There is always a bit of fuzziness as to predictions and models of future events, in terms of what will happen to the sun and how large it will get at its maximum extent. There are some educated guesses as to how big it is likely to get, but we can't predict it down to the inch. There are going to be some significant differences from one model to the next. --Jayron32 02:23, 2 July 2013 (UTC)[reply]

That diagram shows the sun at Earth's orbit - 1 AU radius or 2 AU diameter. Not out past Mars. Rmhermen (talk) 18:35, 2 July 2013 (UTC)[reply]

"Through the Wormhole" Season 4 Episode 3 agrees that the sun going supernova will not swallow Mars. Sandman30s (talk) 20:08, 2 July 2013 (UTC)[reply]

Not while Mars is where it is, anyway. Entirely possible it may be knocked closer by some huge asteroid within the next several billion years. Or something else happens that scientists don't yet think can happen. Long time to go. InedibleHulk (talk) 02:13, 3 July 2013 (UTC)[reply]

What's pictured in this astronomical photo?

Is there somewhere that will tell me what the other objects in this file are? I just have a curiosity about what the big blue object is to the lower left of Andromeda is or what the wide yellow object is in the lower center of the image. Once I was curious about those, I looked more and kept asking "I wonder what that is too!" about various other points of light. So, maybe if there was a site where I could click and zoom around from the Earth's point of view, that would answer all my questions. Is there such a site? Thanks, Dismas|^(talk) 05:00, 2 July 2013 (UTC)[reply]

Stellarium has a very complete catalog of stellar and deep sky objects, and its interface is suitable for beginners as well as expert users. It is free software but it is not web based. I also like the user interface in KStars. If you want a very complete catalog of astronomical objects, suitable for professional use, I'm sure we can point you to some more thorough catalogs, but these tend to require a lot more effort to use. Nimur (talk) 05:19, 2 July 2013 (UTC)[reply]

(For example, once you know the object's coordinate, you can use, e.g. Hubble's digital sky survey catalog, and and just type in coordinates. Most users probably want something a little easier). Also keep in mind that just because something appears point-like and distinct in one image product, that does not mean that it's a distinct astronomical object. So what you see in false color - your photo is mostly composited from invisible ultraviolet light! - gets rendered as a "bright blue point-like star" - but the same area shows as a continuous and nondescript piece of blurry gas in visible light in Hubble's catalog survey. Many very dramatic astronomical photographs are generated using equal parts image-processing science and artistic license to manipulate the input image data. Astrophysicists pore over the spectral data trying to deduce what structure might actually exist in these distant objects. Nimur (talk) 05:31, 2 July 2013 (UTC)[reply]

I've found the site Atlas of the Universe to be a fascinating place to visit over the years. --TammyMoet (talk) 11:22, 2 July 2013 (UTC)[reply]

Google Earth now has a Google Sky star field in it; I've found it very easy to use, already being familiar with the GE navigation. You can apparently view "Sky" through a browser, but I haven't tried that. Matt Deres (talk) 11:28, 2 July 2013 (UTC)[reply]

Google Sky made it impossible for me to ever view our planet as important again. But yeah, that doesn't cancel out the coolness of it. Adds to it, really. InedibleHulk (talk) 02:23, 3 July 2013 (UTC)[reply]

Thanks for the links, everyone. I tried Google Sky but it doesn't name every, or even most, object(s). Dismas|^(talk) 23:56, 2 July 2013 (UTC)[reply]

There's a list of hierarchial checkboxes of things to label in the left-hand pane. Many are unchecked by default. You may want to fiddle with that, if you haven't. InedibleHulk (talk) 02:26, 3 July 2013 (UTC)[reply]

The photo is taken in ultraviolet light. The view in visible light is slightly different (and strangely Commons doesn't seem to have a normal visible light image at a high resolution). The "big blue object is to the lower left" is one of the stars in our own galaxy, the Milky Way. It shows up well in the ultraviolet image, but that star is actually pretty faint, so it isn't listed in List of stars in Andromeda. However a search on Google Sky to get the coordinates and a search on SIMBAD identifies the star as HD3431 (see this page). Other data on SIMBAD suggests the star has a magnitude of 6.86, a spectral type of A0 and is ~615 light years away. The "wide yellow object ... in the lower center" is another galaxy, called the Triangulum Galaxy. Astronaut (talk) 19:46, 4 July 2013 (UTC)[reply]

admission for engineering

hey people I have got into institute if chemical technology for btech oils for first year engineering. wats d opportunity for campus placements? nd does it make a gud branch? — Preceding unsigned comment added by 59.183.34.74 (talk • contribs) Looie496 (talk) 06:41, 2 July 2013 (UTC)[reply]

Presumably that's the Indian Institute of Chemical Technology. On Wikipedia our convention is to spell out words, not write them in text-speak. Looie496 (talk) 06:46, 2 July 2013 (UTC)[reply]

I've got this song stuck in my head...

...and I'd be too embarrassed to tell you what it is. Fortunately, I know from experience it'll be a different song tomorrow. But seriously, it seems it happens to a lot of us. Has any serious research been done on it? How much of the population does it happen to? Does it vary between cultural groups? I sometimes wake up with a song going round in my head that I haven't heard or thought about in years. Is that common? What's really going on with this? HiLo48 (talk) 07:42, 2 July 2013 (UTC)[reply]

Our article on earworms says that "according to research by James Kellaris, 98% of individuals experience earworms". There are a while bunch of references in that article that might tell you more. Gandalf61 (talk) 07:49, 2 July 2013 (UTC)[reply]

Thanks. I'll have a look at that. But the name. Earworms? Never heard of it. No wonder I couldn't find that article. (I did look for one.) The article doesn't have an etymology section. Where did that name come from? (Yeah, I know, it's probably in the sources, but is that name really common?) HiLo48 (talk) 09:06, 2 July 2013 (UTC)[reply]

There's an interesting discussion at Talk:Earworm#Requested move. It's apparently a translation of the German Ohrwurm, but I've seen the English word mentioned frequently in books and articles on popular culture. Ghmyrtle (talk) 09:18, 2 July 2013 (UTC)[reply]

Sounds like a metaphorical equivalent to Earwig. The TV show Brain Games talked about this phenomenon, and if you google the subject [tune stuck in head], there are endless references. It is thought to have some connection to survival instincts. ←Baseball Bugs ^{What's up, Doc?} carrots→ 10:30, 2 July 2013 (UTC)[reply]

Oh so there is such a term! Hehe, remember watching a good ol' SpongeBob SquarePants episode titled Earworm... It really was a worm. :P ☯ Bonkers The Clown \(^_^)/ Nonsensical Babble ☯ 13:09, 2 July 2013 (UTC)[reply]

Earworm is a calque from the German Ohrwurm. Aaadddaaammm (talk) 06:01, 3 July 2013 (UTC)[reply]

There's more discussion on the word here. I've now added it at List of calques. Ghmyrtle (talk) 07:52, 3 July 2013 (UTC)[reply]

Dark matter/energy

Hi I've been listening to a few lectures and debates by Professor Lawrence Krauss and find him a fascinating and progressive champion of science. Is he highly regarded as a scientist (possible Nobel material) or does he fall into the category of celebrity scientists? In more than one of his lectures, he mentioned that ordinary matter comprises only 1% of the universe with everything else comprised of about 30% dark matter and about 70% dark energy. He proudly calls us cosmic pollution and says repeatedly that we are more insignificant than we think! Now, the dark matter article disagrees and says that ordinary matter is 4.9%. Who is correct? Is there more than one school of thought in how the mass-energy of the universe is measured? Sandman30s (talk) 07:51, 2 July 2013 (UTC)[reply]

It's hard to say exactly - but it seems that Krauss is one of a fairly typical group of older scientists who have passed their prime years of doing cutting edge research work and are motivated to move towards "popular science" - explaining this often confusing world to the general public. That's actually not such a terrible thing, we need people who actually understand this stuff to pass it on in a more digestible form! But that likely indicates that he won't be doing work at the Nobel Prize level anymore. That said, there is often a long delay between some great contribution and the recognition of a Nobel - and his early promotion of the idea of dark matter/energy could become sufficiently notable if/when we finally understand what all of that stuff actually is. So while I think it's unlikely, the Nobel committee can be capricious and nothing is impossible.

As for the percentages of dark matter/energy versus regular matter/energy - this is a field of rapid change, and accurate observations are difficult - so we shouldn't be surprised at seeing differences like this. The overwhelming message that "dark" stuff by far outweighs the matter and energy that we're familiar with is unchanged - so rather than ask why there is such a large disparity between 1% and 4.9% of ordinary matter - consider the fairly firm agreement that 95 to 99% of everything isn't ordinary stuff! SteveBaker (talk) 14:18, 2 July 2013 (UTC)[reply]

Thanks! This insignificant clump of stardust thinks that that is a good point... Sandman30s (talk) 19:56, 2 July 2013 (UTC)[reply]

Actually, accurate observations are not difficult, now that Planck (satellite) has mapped out the entire CMB. The fraction that ordinary (baryonic) matter takes up out of the universe's energy density is known as the baryon density, which, according to this article, is 4.56% with an uncertainty of 0.16%. That figure is from WMAP, which launched over 12 years ago. The newer Planck data gives around 4.9%. If Krauss really did say 1% (I've never heard him make such a claim), and you're sure he was referring to the baryon density, his claim is wildly inaccurate. --Bowlhover (talk) 23:28, 3 July 2013 (UTC)[reply]

It will take some effort to find the youtube links and exact times within them, but I can do so if you're interested. He never mentioned the word baryon as far as I can remember, but mentioned 'all stuff that you can see, including you and me and the earth and moon and stars etc.' - so very layman words implying that everything observable by us amounts to only 1%. I thought I was mistaken until I heard the figure twice. Sandman30s (talk) 12:22, 4 July 2013 (UTC)[reply]

citation counts: most cited people

Do we have somewhere a list of people ordered by the number of citations they draw (I mean "cites" that other people use when writing articles / books)? I am wondering if anyone keeps counts, at least for the ~10 most respected scientific publications (but to be honest I would be interested in any study provided they explain what counts and what doesn't. --Lgriot (talk) 08:50, 2 July 2013 (UTC)[reply]

I don't know if Wikipedia has a list, but you'll find plenty of sources online with opinions. How you count citations can make a difference. But in general the most cited scientists are those who developed widely used methods. It's easier to measure the citations to a single paper, and for some authors the number is simply staggering. Protein measurement with the Folin phenol reagent by Oliver H. Lowry has been cited about a quarter of million times, making this paper probably the most cited scientific work ever. You can see a few more examples at this article. That's from the 80s, so the numbers have drifted quite a bit since them, but those papers are still getting thousands of new citations every year, and I suspect they remain the most cited scientific works ever. Someguy1221 (talk) 08:59, 2 July 2013 (UTC)[reply]

Is there like a re-count every year by some organisation? And posted on the web for everyone to see? Googling "citation count" takes you google scholar citations gadget, but they say on that page it currently doesn't work, and I agree, I typed "Dawkins" in the author and got 0 citations as a result. --Lgriot (talk) 09:20, 2 July 2013 (UTC)[reply]

For scientific citations, Google Scholar does indeed work (although Google has a fairly expanded view of what counts as a scientific citation). For authors, check the "Author Search" feature. Dawkins is here, with a bit over 40000 citations. This only seems to work for authors that have some kind of profile, however. Noam Chomsky beats Dawkins hands down only counting the first page of results, but he has no author profile. Stephen Hawking is covered, with ~810000 citations. --Stephan Schulz (talk) 09:42, 2 July 2013 (UTC)[reply]

Thanks a lot, Mr Schulz, I was using it wrongly.--Lgriot (talk) 13:41, 2 July 2013 (UTC)[reply]

Resources described here may be helpful, too. -- Scray (talk) 14:56, 2 July 2013 (UTC)[reply]

Charles Murray's Human Accomplishment addresses this topic on a worldwide basis, giving statistics for work done up to 1950. I am fairly certain Newton comes in first place. μηδείς (talk) 22:05, 2 July 2013 (UTC)[reply]

"Physical" dark matter chunks near Earth?

There's been discussion of dark matter around here for some time [5] ; meanwhile, more "dark matter galaxies" are being announced or suspected: [6] [7]

Now, I understand there are many models of dark matter which represent it as hot, fast-moving, even non-self-interacting, so that it doesn't form physical "chunks". Still, I thought I should ask: how much can we currently restrict that model based on what has been observed? I assume we can't absolutely rule it out (assuming more than one kind of dark matter may exist) but we could limit the amount that is possible?

In other words, I suppose if you had a "dark matter planet" that went through or even near the Earth, we'd really find out about it due to tidal effects. If a "dark matter asteroid" is possible it would presumably make anomalies in satellite motion. And "dark matter stars" ought to leave other suns circling without a visible reason. I assume someone has looked for the limits of such evidences?

A particular scenario that appeals to me is a supernova remnant, which is often asymmetrical, shooting a remnant off into space at high speed. Presumably any dark matter that it gobbled up during life should remain gravitationally bound at the point of origin, right? So... does anything turn out to be perturbing the gas remaining at that point? Wnt (talk) 15:35, 2 July 2013 (UTC)[reply]

The strongest limits on this come from gravitational lensing, see e.g. here. Count Iblis (talk) 16:49, 2 July 2013 (UTC)[reply]

To form small clumps you'd really need the dark matter to interact with itself or ordinary matter so it could be slowed down. Otherwise a particle just speeds up towards a centre of mass, then goes round and away again like a comet. Random whizzing around can clump under gravitation to give a cloud but it won't lead to small chunks like stars (well not unless it is dense enough to start forming black holes). Dmcq (talk) 08:52, 3 July 2013 (UTC)[reply]

There is no scientific evidence for "dark matter". --Kharon (talk) 21:14, 3 July 2013 (UTC)[reply]

Well, the reason why I mentioned the supernova was that I figured, even if dark matter doesn't self-interact under any circumstance but gravity, it should still sink to the core of the supernova and then remain gravitationally bound after it blows apart. Unless the stuff is so "hot" (?) that it "evaporates" right out of the gravity well anyway?

(to clarify, I'm not so clear on this: even if the dark matter collides with nothing, including itself, shouldn't the orbital mechanics of the matter eventually lead to some particles being flung out to infinity while others lose speed and remain permanently within the growing star during the billions of years leading up to the supernova?) Wnt (talk) 22:14, 3 July 2013 (UTC)[reply]

There are no orbital mechanics left in the common inbetween dimensions of astronomical distances between stars and Star systems. If one would calculate the Relation between space "filled" by matter and space containing nothing you would find some very oddly tiny result. Same with distance. Pluto is ~4 Light Hours away from our Sun. The next star Alpha Centauri is around 35 000 Light Hours away (and astronomical concidered "near"). --Kharon (talk) 00:14, 4 July 2013 (UTC)[reply]

Interaction should in principle lead to kinetic energy redistribution in terms of a thermal model, though the time scale might be huge, especially if the interaction is weak. The average kinetic energy of the chunks relative to some gravitational picture would probably be key. In effect, small particles should behave as a gas, and if the initial average temperature is more than a few K, unless there is a mechanism (e.g. radiative) extracting energy from them collectively, they would presumably never coalesce into anything more dense than "clouds" – in the case of primordial hydrogen, electromagnetic radiation must have been crucial in the formation into galaxies and stars. Weak interaction with normal matter at the atomic level might lead to some extraction of energy, and to reduction of the local temperature, and hence some clumping. One supposition/model I've seen (a public lecture by an astrophysicist) gives local dark matter density going by a simple power law around centres (i.e. not within a star, but inside and extending out from it, like an atomic 1s orbital), but it was not clear what the minimum size was – a star? a galaxy? In any event, such cooled clumps of gravitationally bound dark matter seem to be a serious consideration, but if significant clumping occurred at the level of stars, we should have had abundant evidence of it from planetary orbital observations. — Quondum 11:12, 4 July 2013 (UTC)[reply]

What's the sourest object in the known universe?

Any ideas? Just a question that occurred to me when eating one of those super-sour Toxic Waste sweets recently. I do seem to recall that something was once announced as the most foul-smelling object in the known universe... --Kurt Shaped Box (talk) 20:53, 2 July 2013 (UTC)[reply]

If sourness is the sensation of acidity, fluoroantimonic acid is at the top of superacids. Theoretically if you could eat a spoonful of protons those would be the most acidic thing there can be. Sorry for how the dull the answer is... 88.112.41.6 (talk) 21:08, 2 July 2013 (UTC)[reply]

If sourness is ability to donate protons then you probably can't go past ionized hydrogen, and there is plenty of that in the universe. Graeme Bartlett (talk) 21:18, 2 July 2013 (UTC)[reply]

I started wondering what would happen if you had pure protons at an everyday life density. Say a spoonful of water and instantaneously remove all the oxygen nuclei and electrons. Those protons wouldn't like to be close to each other due to electrical repulsion, would they? Would that be minor heating of the spoon or a big-hole-in-the-ground event? 88.112.41.6 (talk) 21:58, 2 July 2013 (UTC)[reply]

It is impractical to remove the electrons - the coulomb force is amazingly strong, and you'd have to expend a lot of work to separate the electric charges. So, in your scenario, a necessary condition is an input of a huge amount of energy to dissociate (and then separate) the ions and electrons. As a result, you'd have a very hot ionized mass of hydrogen. You can easily calculate how hot you need to get to ionize the hydrogen: it's the ionization energy divided by the heat capacity. (!!). Accounting for adiabatic expansion which is reasonable when you compare the time-constant of the expansion to the effective rate of heat exchange with the outside air, I think you'll find it hard to keep the resulting explosion contained in a spoon-heap-sized volume! Nimur (talk) 22:30, 2 July 2013 (UTC)[reply]

An Assistant-Principal at a school I once taught at was a really sour old b.... HiLo48 (talk) 23:34, 2 July 2013 (UTC)[reply]

Perhaps, you mean "sourest non-toxic substance"? Plasmic Physics (talk) 02:29, 3 July 2013 (UTC)[reply]

Don't think that really helps. Vinegar isn't considered toxic but glacial acetic acid is. 202.155.85.18 (talk) 05:01, 5 July 2013 (UTC)[reply]

One should take care that one is dealing with the correct concept. "Sourness" might relate to hydronium concentration rather than proton donation. — Quondum 03:03, 3 July 2013 (UTC)[reply]

Something is wrong with the magnetic induction " B" !

When we analize the interaction between two current carying conductors we first represent the magnetic induction "B" following the right hand rule. But, if you look back at the origine of this representation you can find that it comes from Faraday and the orientation of the magnetic induction "B" was based on the pattern of iron filings formed around a magnet bar which resemble to " field of lines" conneting the two poles. If you look closer the iron piling particles also can be considered tini magnets and their orientation will always be that their internal atomic currents that creates their magnetic field will be aligned with the internal atomic currents of the large permanent magnet bar so they will tend to have the same direction ! The independent "lines" are formed because the adjacent particles of iron will align their internal currents with the stronger current of the large permanent magnet bar while between the "lines" there will be repulsion, also particle of iron from a "line" will form chains with the top and the bottom particle so that their internal currents will be aligned too. So now from the two parallel electric current situation we arrive to another two parallel electric current situation! And the real magnetic field looks more like "something" that is allong the lenght of the conductor. Think about two ships on water that moves parallel to each other in the same direction. Because of Bernoulli effect the ships will be drawn together, but if they move in opposite directions they will be pushed away from each other...The same it seems to be with the magnetic field too. There is no such a thing like magnetic induction "B" that is tangent to the conductors or circle the conductor...its just an illusion ! Can you see the error? — Preceding unsigned comment added by 71.185.132.57 (talk • contribs)

Yes, your error is that you are confusing magnetic field with magnetic induction. These terms refer to distinct physical entities. If you use terminology differently from everyone else, you won't be able to understand the commonplace explanations. Magnetism obeys simple rules that have been experimentally tested and verified with increasing accuracy for around two centuries; if something was catastrophically wrong with our understanding, we would all have noticed! Nimur (talk) 21:17, 2 July 2013 (UTC)[reply]

I think that you are confusing "magnetic induction B" which is also called "magnetic field" (read wikipedia :) with "electromagnetic induction" ... Saying that " magnetism obeys simple rules" its a very superficial statement, anyway.

I noticed our disambiguation page - I read Wikipedia - and many other things - quite extensively! I'll go out on a limb here and say "usage of the term 'magnetic induction' to refer to the magnetic field is incorrect and should be eliminated from the disambiguation page." I had no prior recollection of ever hearing the term "magnetic induction" abused this way. In deference to my limited knowledge, I referenced two university-level textbooks on electrodynamics that I keep handy next to my bed for just such situations. Tipler's Physics for Scientists and Engineers gives a great description of the history of the magnetic field, and carries a full chapter titled "magnetic induction." Magnetic induction is defined as the process by which "emfs and currents are caused by changing magnetic fields..." Nowhere in the chapter, nor in the convenient glossary, does this text use the term "induction" to refer to the field.

David J. Griffiths' "Introduction to Electrodynamics", §6.3, has a special note on the topic, while discussing fields in materials, and I quote: “Many authors call H, not B, the "magnetic field." Then they have to invent a new word for B: the "flux density," or magnetic "induction" (an absurd choice, since that term already has at least two other meanings in electrodynamics). Anyway, B is indisputably the fundamental quantity, so (Griffiths) shall continue to call it the "magnetic field," as everyone does in the spoken language.” I guess this scores a point for the OP - the term is used somewhere. But not in modern textbook-definition usage. A further note, in my edition: “For those who disagree, (Griffiths) quotes A. Sommerfeld's Electrodynamics (1952)... "The unhappy term 'magnetic field' for H should be avoided as far as possible. It seems to us that this term has led into error none less than Maxwell himself" ...“

I was willing to entertain the notion that the terminology is a foreign-ism, or archaic (... it would not be the first time I encounter unfamiliar physics lingo, only to discover that all students in, say, Ghana or India use different terminology than I do). So I went straight to my digital copy of "Experimental Researches in Electricity," (which is available free online) to refresh my memory - I never recalled its author using the term "magnetic induction" incorrectly! Michael Faraday uses terminology in a way I would agree with; "magnetic induction" is described as the process of inducing a current using a changing magnetic field, and never to refer to the magnetic field itself. So, I know of no historical or archaic usage, but this was arguably a very short literature survey. Based on Sommerfeld's comments, Maxwell may be the source of the original terminology confusion; I'll probably dig up some Maxwell writings for my own entertainment, but I don't usually find those very enjoyable to read, because his writing style is confusing.

I hope if nothing else comes from these references, you'll have some good reading suggestions to help clarify the topic. Griffiths' chapter on magnetism and its interaction with magnetized materials is excellent and may clear up your original question. If nothing else, it may dispel any rumors that I make flippant or superficial contributions! Nimur (talk) 11:24, 3 July 2013 (UTC)[reply]

For anyone who is still waiting on the edge of their seat for the startling conclusion: it was in fact Maxwell who first used the term 'induction' in this way, in A Treatise on Electricity and Magnetism, Part 3, Chapter 2, Magnetic Force and Magnetic Induction. I will not be the first, nor the last, physicist to say that Maxwell's writing-style and choice of terminology was not very clear, and it certainly deviates from modern terminology. Nimur (talk) 18:07, 4 July 2013 (UTC)[reply]

July 3

Bluejays and cardinals

How are bluejays and cardinals related evolutionarily? Do they share a common ancestor? What is their recent most common ancestor? Also, is it legal in the United States to capture a SMALL wild animal like a blue jay or cardinal and keep it as a pet or as dinner, or would a person need a license no matter what? Sneazy (talk) 01:15, 3 July 2013 (UTC)[reply]

The easiest way for you to see how two organisms are related is to check the infoboxes in their articles. If you look at Cardinal, you will see: its kingdom is Animalia, phylum Chordata, class Aves, order Passeriformes, family Carinalidae, genus Cardinalis, and species Cardinalis cardinalis. Looking at Blue Jay, its kingdom is Animalia, phylum Chordata, class Aves, order Passeriformes, family Corvidae, genus Cyanocitta, and species Cyanocitta crostata. So the two are identical in descent down to the level of order: both are passerine. They differ at the family level, with the Blue Jay being a corvid.

The legality of capturing, killing, or eating wildlife varies by jurisdiction, and in any case, we don't offer that sort of legal advice. - Nunh-huh 01:36, 3 July 2013 (UTC)[reply]

Indeed, but see Migratory Bird Treaty Act of 1918. Matt Deres (talk) 01:44, 3 July 2013 (UTC)[reply]

@Nunh-huh: Having written an undergraduate research paper on the evolution of a specific type of passerine birds, the lyrebirds, I am not sure what you are trying to imply in your post. All organisms interact on a species level. Although the hierarchical classification system is useful in taxonomy, it does little to answer the question of how bluejays and cardinals evolved from ancestral passerine birds. Sneazy (talk) 02:58, 3 July 2013 (UTC)[reply]

Your question contains no indication that you understood that both species were passerine birds; I was simply pointing you towards that information. You didn't ask how blue jays and cardinals evolved from ancestral passerine birds, you ask if they had a common ancestor. - Nunh-huh 22:06, 3 July 2013 (UTC)[reply]

Well, I was expecting a much more fuller answer. You know, one that has more substance. :P Sneazy (talk) 00:09, 4 July 2013 (UTC)[reply]

You got what the question merited. You're welcome. - Nunh-huh 00:37, 4 July 2013 (UTC)[reply]

No, I didn't. The recent most common ancestor can't be a broad category. Saying that blue jays and cardinals derive from passerine birds is like saying humans derive from the apes. It's not specific. So, I didn't get what the question merited. A better response would be to list an ancient passerine bird species that gave rise to the blue jay and the cardinal. Sneazy (talk) 18:37, 4 July 2013 (UTC)[reply]

In which case you are not going to get a good answer anyway--or not one better than "it would be the same as whatever animal is the common ancestor of the crow and the sparrow." Bird fossils aren't that well represented, and the passerines are so morphologically similar that classification is not certain, and all of bird classification has been under heavy flux for the past 25 years. μηδείς (talk) 19:03, 4 July 2013 (UTC)[reply]

Although classifying organisms by morphology is an useful method, it cannot be the only method, because morphology is really what an organism looks like, and looks can be deceiving. Since the two species are alive, I would probably suggest a DNA analysis on the blue jay and the cardinal and make a phylogeny based on the modified characters. Just because Mother Nature has made them morphologically similar doesn't mean that they are genetically similar. Maybe Mother Nature pressures the birds to evolve in a certain shape, because that certain shape is most advantageous for survival. Sneazy (talk) 23:55, 4 July 2013 (UTC)[reply]

They are not at all close within the passerines. Jays are quite close to crows within the crow superfamily. Cardinals are close to sparrows in the sparrow superfamily. (Search for cardinal and jay in our passerine article) Keeping a Northern Cardinal can get you a fine due to the Migratory Bird Treaty Act of 1918. If you want to keep a bluejay you will deserve whatever you get. I would love to see a hybrid, however unlikely. μηδείς (talk) 03:15, 3 July 2013 (UTC)[reply]

1. Where did you get that knowledge?

2. It still does not explain how the two types of birds might have evolved or what might the specific selective forces be. Sneazy (talk) 03:32, 3 July 2013 (UTC)[reply]

That second question is very interesting, because as far as I am aware, "what might the specific selective forces be" is very rarely known, am I right? They are too many factors, and we haven't collected the data for most species. But maybe someone with better understanding of the science will correct me, and I will be very happy to hear what they have to say. --Lgriot (talk) 08:32, 3 July 2013 (UTC)[reply]

1) look at the article Passerine and the position of the corvidae and the cardinalidae within the taxonomy. (2) requires a treatise, μηδείς (talk) 16:33, 3 July 2013 (UTC)[reply]

Total solar eclipse of Egypt circa 3100 BC?

Is there some way to calculate when, if ever, one of these occurred over Egypt around about this period? Also, I understand that a total eclipse is relatively rare (recurring only 375 years or so according to this source) - does this value fluctuate depending on ones position on the globe? 70.112.97.77 (talk)

One important distinction is whether you mean a total solar eclipse at one particular point (which is rare) or anywhere on Earth (which is fairly common). That is, each eclipse is normally only a total eclipse for a small portion of the Earth (if anywhere at all), with the rest seeing either a partial eclipse or no eclipse at all (including the half of the Earth in night at the time). StuRat (talk) 03:00, 3 July 2013 (UTC)[reply]

here is NASA's list of total eclipses for 3999-3000BC, with lat and long coordinates. Cairo is near 30N, 30E. MChesterMC (talk) 08:20, 3 July 2013 (UTC)[reply]

Okay, so it looks like no total solar eclipses for that region around that time. Thanks for the help! 70.112.97.77 (talk) 18:35, 4 July 2013 (UTC)[reply]

NYC and nuclear attack

If, in the 1960s the Soviet Union decided to attack a city like New York with nuclear weapons, how long would humans have to wait before the city is safe enough to re-enter without threats of radiation poisoning? Thanks. 64.229.207.42 (talk) 03:06, 3 July 2013 (UTC)[reply]

It would depend on the bomb and how delivered . Hiroshima and Nagasaki are habitable now and have been for some time. μηδείς (talk) 03:18, 3 July 2013 (UTC)[reply]

The thing with radiation is that it doesn't just completely disappear some day. Instead it gradually reduces in magnitude. So, when exactly it is "safe to return" is debatable. Also, you said "radiation poisoning", which requires a fairly high level of radiation. Lower levels continue to cause an increased incidence of cancer for years to follow. StuRat (talk) 03:19, 3 July 2013 (UTC)[reply]

Also, there tend to be "hot spots" remaining where the fallout dust and debris has collected for one reason or another - and those places remain more dangerously radioactive for longer. Other issues are that the primary radiation from the bomb can make other materials radioactive - and the half-lives of those materials is wildly variable.

As StuRat points out, radioactive decay isn't an all-or-nothing thing. If the particular radioactive isotope left behind by the explosion has a half-life of a year, then the radiation levels will halve every year from then on...but there is (essentially) never a day when there is no radioactivity left - and any amount of radiation increases your lifetime cancer risk. After the Chernobyl reactor disaster, people halfway around the world and three decades later still have a small increased cancer risk because of it. It's estimated that even 80 years after that explosion, your personal risk of getting thyroid cancer will be 0.3% higher than it otherwise would have been - solely because of that accident.

SteveBaker (talk) 20:38, 3 July 2013 (UTC)[reply]

Would depend largely on weather conditions as land contamination from a nuclear bomb would be caused mostly thru Nuclear fallout, not directly as most wrongly asume. --Kharon (talk) 21:02, 3 July 2013 (UTC)[reply]

There are a lot of variables. For one thing, if it was an attack in the 1960's then New York would have been out of range of soviet missiles. The bombs would have been delivered in the secondary attacks by aircraft. These would most likely have carried 'city busters'. To put it another way, very large hydrogen bombs of many megatons. The initiation hight of such bombs (limited by high the delivery aircraft could fly) would probable get graded as a 'ground burst'. In other word, a third or more of the fire ball would make contact with the ground. In this scenario, a great deal of fall out is produced -measuring many hundreds of rads. I don't have references to hand but your looking at two months before a short sojourn into the area could be safely attempted (longer, if you are going by modern standards of allowable exposer rates) . The Hiroshima and Nagasaki bombs were both air bursts. Therefore, after about an hour, the radiation had decayed enough, not to cause any short term hazard. Those, that put their cancers down to entering Hiroshima the day after are most likely grasping at straws. --Aspro (talk) 23:18, 3 July 2013 (UTC)[reply]

Are you sure that New York would have been out of range of Soviet missiles? What of those medium-range missiles in Cuba? Or, for that matter, what of submarine-launched missiles? 24.23.196.85 (talk) 00:55, 4 July 2013 (UTC)[reply]

Indeed, Russian Submarines had the technology to do it according to our article: "the Soviet Union made its first successful underwater launch of a submarine ballistic missile in the White Sea on 10 September 1960", unless there is a claim that these misslies could not carry a nuclear warhead. So from that date on, New York was never out of range. --Lgriot (talk) 08:03, 4 July 2013 (UTC)[reply]

Those are fair questions. This is how I understood it at the time: During the 1960's, if war between the soviet union and the 'West' broke out, the major activity would have first taken place in Europe. Thus, one had American forces stationed in Germany with their atomic demolition W54's in order to destroy bridges from Russia in to to Europe. There were atomic land-mines and other things as well in place. It was therefore in Europe, that the Soviet military advantage lay. Cuba only had 'very' short range nuclear missiles – not capable of reaching the US main land (the longer range missiles never arrived due to the blockade). The other Russian missiles were based in eastern Russia and could only target north western US states. In those existing 1960 scenarios, there was no strategic advantage to the Soviets of nuking New York. Civilians can't hit back instantly, so one concentrates on their military forces that can. Therefore, all those now forgotten fall out shelters in NY were only created for political purposes (with a view that the Soviet missile range would improve over time). If secondary strikes became a strong possibility, then evacuation would have been a better option. So no. I don't see any earthy reason why NY should have expected a nuclear strike by missile. It was the way that WWIII was envisioned in those days.--Aspro (talk) 21:03, 4 July 2013 (UTC)[reply]

Actually, the SS-4 missiles deployed to Cuba had a maximum range of 1200 miles, which would have allowed them to reach as far as Richmond, VA, Corpus Christi, TX, and (barely) Washington DC. 24.23.196.85 (talk) 06:13, 5 July 2013 (UTC)[reply]

The article on the Chernobyl disaster has quite a bit about the ongoing effects of radioactive contamination, including guesstimates of timescales for the area to become safe. Astronaut (talk) 18:34, 4 July 2013 (UTC)[reply]

I wonder if it is accurate to equate Chernobyl and a 1960's nuclear bomb? The Russian reactor had a large inventory of decay products from the nuclear fuel, in isotopes readily absorbed by the human body and isotopes with a very long half life, while a bomb might not. The goal of nuclear war planners was to fight and win a war, not to make the Earth an uninhabitable planet. Is it claimed that the Soviets would have gone out of their way to hit NYC with a "dirty bomb" encased in cobalt or whatever, or that 1960 nuclear strategy called for dirty ground bursts rather than high altitude bursts with a wider circle of destruction from blast and flash ignition? The ground burst claims run counter to US civil defense literature of the early 1960's which also predicted a short half-life for the fallout, so it would be safe to leave shelters after about 2 weeks. It was not expected that cities would be uninhabitable due to radiation for years or whatever. Edison (talk) 23:40, 4 July 2013 (UTC)[reply]

Bipolar Disorder associated features

Hi guys,

My post is related to bipolar disorder.

I am curious as to what features exist characteristic of bipolar disorder, particularly any features that are exclusive to the disorder. For instance, I am aware of ideas of reference as a feature of psychotic mania. Another example might be the connection between creativity and bipolar.

Are there any other major or minor examples of associated features (AF) of bipolar disorder that could be added to the current page on AF? (Second link)

Thanks! I have a personal interest in this as I am a 19 y/o male recently diagnosed with bipolar.

Jeremy

GRHooked (talk) 09:37, 3 July 2013 (UTC)[reply]

Have you looked at our article on hypomania? Looie496 (talk) 14:53, 3 July 2013 (UTC)[reply]

Remember that bipolar disorder is something of a spectrum, so you may want to check out spectrum disorder and Bipolar_spectrum#Bipolar_spectrum. You may therefore have trouble finding things exclusive to the condition, except in extreme cases. IBE (talk) 03:48, 4 July 2013 (UTC)[reply]

Rehydration of troops in Iraq/ Afghanistan

Hi,

After having watched Jarhead, and also talking to troops that have served in Iraq/Afhanistan, it seems like good hydration is a massive part of serving there. Since a lot of the troops come from colder areas where less water is lost from sweat, this could cause a problem with troops not being used to drinking so much water so often, since they must sweat buckets under the "perfect storm" of hot weather, stress and heavy exercise. Did the US/ other countries have a way of preparing the troops before they went or while they were there to get troops used to drinking so much water (other than rehydration tablets). If so what did it entail? Obviously they just got them to drink a lot very often, but was there a particular regime they followed? 80.254.147.164 (talk) 11:47, 3 July 2013 (UTC)[reply]

You don't need training to know when you're thirsty and to take water then. Those drinks companies telling people they need to hydrate when they are not thirsty are a menace, drinking too much fluid is far more of a danger than mild dehydration. See water intoxication. Dmcq (talk) 12:28, 3 July 2013 (UTC)[reply]

Yes, I agree that for most it's pretty easy and unessecary to drink when not thirsty. But if you are in such a difficult environment where you are unsure when the next time you will be able to drink is, or when the next time that they will have to run for 3 miles in heavy gear will be, you might need a disciplined approach to keep yourself topped up, or at least repetition to get yourself in the habit. How much water does each soldier take on patrol? Or is water freely available enough that they can obtain bottles fairly easily? 80.254.147.164 (talk) 13:19, 3 July 2013 (UTC)[reply]

Three miles in kit? Human Mammal, Human Hunter - Attenborough is a clip showing a man run down and kill a kudu over eight hours during the heat of the day in the Kalahari desert. Persistence hunting is thought to be one of the first human adaptations. Dmcq (talk) 13:45, 3 July 2013 (UTC)[reply]

I saw that show - but the guy was nearly naked - and almost completely unencumbered with equipment. He wasn't dressed in battledress, bulletproof vest, with a helmet and a 100lb pack on his back. Also, he had been adapted to the environment since birth rather than coming from someplace where the temperatures never get over 90F - and he was under much less stress because there weren't potentially snipers and IED's around every corner. It's not a remotely comparable situation. SteveBaker (talk) 16:58, 3 July 2013 (UTC)[reply]

The following is OR but I have some confidence in it. I lived for 20 years in Tucson and did a lot of desert hiking in Afghanistan-like conditions, needing to drink literally gallons of water a day (actually Gatorade or even lukewarm ice-tea are better than plain water, but whatever). My experience is that the ability of the body to process that much water develops over time. Early in the hot season I would find it difficult to drink as much as I needed (there's a sort of sick feeling), but after a few hikes I could handle a lot more. I also did many hikes with visitors from colder places, and found that they had a lot more difficulty handling the heat than I did. Looie496 (talk) 17:12, 3 July 2013 (UTC)[reply]

You probably were able to sweat properly. The problem with wearing an army uniform with bulletproof vest etc is not being able to sweat properly. I believe they try and use materials that wick the sweat away but heat stroke is a real possibility if they can't keep their temperature down. A place with high humidity now, they can be quite unpleasant, you just lie there waiting for it to get cooler. Dmcq (talk) 18:12, 3 July 2013 (UTC)[reply]

Something especially nasty happens when the air temperatures get above body temperature (we had three 106 degF days here in Texas last week - so I speak with some authority!) Normally, when the temperatures are more sane, your body creates a volume of warm air around it - an effect which clothing accentuates by trapping that air. Removing clothing and having a nice breeze helps that warm air to be moved away from you - so you feel cooler. That's why fans work - they don't cool the air - they just let you feel the true ambient temperature. However, when the ambient temperature gets above body temp, all of this goes horribly wrong - because you're replacing body temperature air with hotter air - and that makes matters worse. A "cool breeze" becomes more like opening an oven door!

Moving air around still helps a little bit though because the only way you can lose heat under those circumstances is by sweating and letting the evaporating water carry the heat away. But if you gradually build up a layer of humid air around your skin, that slows down the evaporation rate - so a gentle breeze still helps to some degree by reducing the humidity close to your skin. The idea behind wearing seemingly warm clothing in hot weather is to prevent that higher-than-body-temperature air from reaching you - but it needs to be made so as to allow sweat to wick away and evaporate on the outside of the clothing in order to avoid humidity build-up. This ends up being a tricky business.

If humidity is close to 100% and temperatures are over body heat, then you have a really dangerous situation. Sweat doesn't evaporate because of the 100% humidity - and breezes only make you hotter - so there is really nothing to keep your body temperature reasonable. At that point, the only thing you can reasonably do is to keep heat-generating activities to a minimum and hope that the temperature drops before you die from it.

SteveBaker (talk) 20:20, 3 July 2013 (UTC)[reply]

There are sources to be found about this. I searched "soldiers afghanistan hydration rules" and came up with [8] on the first page. This really isn't my field, and some of the considerations involved in deciding on these protocols are likely not obvious. Wnt (talk) 22:11, 3 July 2013 (UTC)[reply]

Surely it's worth remembering now, as the leaders of the countries involved recently seemed to forget, that people from cold places have tried to invade these places many times before, going back at least a hundred and fifty years, and probably much longer. Britain and Russia come to mind. Their soldiers would not have had access to modern re-hydrating drinks, nor almost certainly to the mere quantities of fluids available to participants today. I don't know how they coped, but I often wonder about it. HiLo48 (talk) 22:20, 3 July 2013 (UTC)[reply]

We're the same species and most people have little difficulty in acclimatizing to hot weather and humans evolved in such conditions long before the idea of re-hydrating drinks was oversold. Dmcq (talk) 23:47, 3 July 2013 (UTC)[reply]

Yes, but as I already explained, these people are running around in bullet proof vests, combat fatigues, helmets and 100lb packs...we evolved for exercising in not much more than a spear and a loincloth. This kind of abuse of the body requires special intervention. SteveBaker (talk) 03:10, 4 July 2013 (UTC)[reply]

I was answering HiLo48's question just above. The document that Wnt just above that again pointed at gives the answer about the soldiers nowadays. They have good answers in that though they still seem to talk more in terms of dehydration rather than heat stress. They still buy into what the drinks companies say to some extent though they have cut down on the recommended water because of the casualties from water intoxication. Dmcq (talk) 08:24, 4 July 2013 (UTC)[reply]

Not every soldier has a 100lb pack on its back. And even when they are supposed to carry one to their place of deployment, they don't go on patrol like that. Many soldiers also come from a pretty hot weather region, and could be stationed in hot places like Kuwait or Saudi Arabia before Iraq. Besides that Afghanistan is not that hot. Many regions in the US are hotter. OsmanRF34 (talk) 00:59, 5 July 2013 (UTC)[reply]

I think some of the answers above border on medical advice. I worked in the Australian desert for years, and we were constantly counselled by our employer to drink water until our urine was a pale straw colour. There were posters next to the urinals with various colours showing us to drink more if we were anything less than the palest straw shown. The posters also had sayings like "By the time you feel thirsty, you're already dehydrated". 202.155.85.18 (talk) 05:36, 5 July 2013 (UTC)[reply]

Actually, I found the exact images [9], [10] and [11]. 202.155.85.18 (talk) 05:41, 5 July 2013 (UTC)[reply]

Perhaps you should send the american army recommendations above to your employer. Dmcq (talk) 13:19, 5 July 2013 (UTC)[reply]

Those charts seem a little hard to interpret, in part because they seem to be different colors, and mostly because it's not specified where you're supposed to be looking at the urine - in midair (where it depends on flow rate, which depends on how dehydrated you are!) in a vessel of what depth, etc.? Also of course because urine varies in color depending on diet. Wnt (talk) 15:24, 5 July 2013 (UTC)[reply]

I should also note that water intoxication cited above says that it is actually a very rare condition. I would be curious, though, whether water is "addictive"? In general heat acclimatization actually increases water requirements [12] but does prolonged restriction of water induce, say, higher levels of some transporter proteins in the kidneys? To be clear, water rationing is discredited in the military sense [13] - but I'm not sure if that's because modern militaries assume the ability to transport large amounts of water and are more worried about other ways of getting killed due to poor performance rather than running out of water. Wnt (talk) 15:32, 5 July 2013 (UTC)[reply]

To address HiLo's query about how previous generations of soldiers coped with conditions in Afghanistan, it should be remembered that the British had had a century of experience of operating in India before venturing there. The troops used in the Second Afghan War were those stationed in India and were thus fully acclimatised beforehand, tours of duty being seven years if I recall correctly. British officers employed tactics on the march such as enforced rest periods during the hottest part of the day, and must have been aware of how hard they could push their men, through hard experience. However, when these precautions were set aside in Lord Roberts' famous forced march to the Battle of Kandahar in 1880 (300 miles in 3 weeks): "The pace of the march was taking its toll with soldiers falling sick at the rate of 500 a day". [14] Alansplodge (talk) 17:08, 5 July 2013 (UTC)[reply]

The standard speed for a "forced march" at that time was 20 miles per day. 300 miles in 21 days is 15 miles per day - so they had given the men a significant reduction - despite the extreme urgency. Also, consider that at the end of that march, the men managed a significant victory - so it should be said that the pace of the march was actually about right in terms of the overall course of the war - better to lose some men to heat exhaustion along the way than to fail to relieve the garrison by arriving too late and take much heavier casualties overall. It was a tough call - and Roberts got it about right. SteveBaker (talk) 21:06, 5 July 2013 (UTC)[reply]

July 4

Colds and bacterial infections

Why do many bacterial infections occur at the same time as or straight after a cold and vice versa? Is it just because the immune system is weakened? Clover345 (talk) 12:14, 4 July 2013 (UTC)[reply]

It's a myth that these secondary bacterial infections are commonplace: This document says that: "The common cold rarely leads to secondary bacterial infections that require antibiotic treatment." - couldn't find details of why secondary infections happen though. SteveBaker (talk) 14:04, 4 July 2013 (UTC)[reply]

I read that as being equivalent to "The common cold regularly leads to minor secondary bacterial infections but they rarely require antibiotic treatment." Our article on common cold says: "Secondary bacterial infections may occur resulting in sinusitis, pharyngitis, or an ear infection. It is estimated that sinusitis occurs in 8% and an ear infection in 30% of cases." Dbfirs 20:47, 4 July 2013 (UTC)[reply]

Boiling water in a kettle

Which would use more energy? 1) Boiling 500ml of water from room temperature and repeating; or 2) Boiling 1 litre from room temperature. Thanks. 163.202.48.125 (talk) 13:05, 4 July 2013 (UTC)[reply]

This has the appearance of a homework question, and our policy is not to do people's homework for them. Looie496 (talk) 13:10, 4 July 2013 (UTC)[reply]

In a real-life scenario or in a imaginable scenario where you don't have to heat the pot and this doesn't lose heat at all (that means, all heat gets transfered directly to the water without loss)? Try to think about the first case, what would be more efficient? OsmanRF34 (talk) 13:20, 4 July 2013 (UTC)[reply]

I guess I'm flattered you think this is homework - it means I phrased the question well. It is not homework - I don't do homework since I'm not in school. And I'm talking about a real life scenario. So I boil 500ml and then boil another 500ml immediately after (I suppose it matters if I wait before boiling the second one) OR I just boil the 1 litre. 163.202.48.125 (talk) 13:29, 4 July 2013 (UTC)[reply]

I don't believe homework questions are well worded or well conceived. Normally, they try to exclude lots of constrains that matter in real-life and somehow have hints to the answer desired. OsmanRF34 (talk) 14:31, 4 July 2013 (UTC)[reply]

If your kettle is large enough to boil one liter at once, it's almost certainly more efficient to do it in one go. Your heat loss into the environment is a function of temperature and surface area, and with two times 500 ml, you will still have the same surface of the kettle that heats up and loses energy, and you also have a larger water surface. But you should be able to find out with a simple experiment. Just do it and time it. Standard electric kettles are either on or off (and you can hear/see when they auto-shut-off activates), so energy use is (modulo very small effects) directly proportional to time. --Stephan Schulz (talk) 13:52, 4 July 2013 (UTC)[reply]

Thanks, Stephan! I didn't think of that experiment. Does that mean that the amount of current passing through those heating rods in the kettle is the same as long as the kettle is switched on? 163.202.48.125 (talk) 15:25, 4 July 2013 (UTC)[reply]

Yes, a standard kettle will have a nearly constant current draw (when the coils heat up, resistance goes up a little bit, but that is a very minor and transient effect). Since resistance is nearly constant, and Voltage is constant (modulo brownouts ;-), the kettle will always draw nearly the same current, and use nearly the same power. --Stephan Schulz (talk) 17:02, 4 July 2013 (UTC)[reply]

Also, if your concerned about efficiency, boil it with a lid of some kind on it. It should come to a boil faster than if it's open to the air. ←Baseball Bugs ^{What's up, Doc?} carrots→ 15:23, 4 July 2013 (UTC)[reply]

Better still, pump all the air out of the kettle and the water will boil with out the need to even switch the kettle on.--Aspro (talk) 21:16, 4 July 2013 (UTC)[reply]

For certain values of "boil", yes. --Carnildo (talk) 08:53, 5 July 2013 (UTC)[reply]

Look at it like this: The energy to consumed in raising the temperature of the water is the same, no matter how you do it. So all we're concerned about is losses in the system. Since kettles don't make much sound, emit magnetic fields, glow or anything like that - we can assume that almost all of the electrical energy goes into making things hot. The water, the kettle and the surroundings (because kettles aren't generally well insulated). We can ask where the energy that didn't go into heating the water went. If we consider two experiments (boiling two half-liter loads and boiling one full-liter load) - in each case, the kettle is at the ambient temperature at the start and close to 100C at the end. So the amount of energy residing in the kettle is the same in both cases. So the only difference is in the heat lost to the environment.

OK - so Isaac Newton discovered that the rate of temperature loss is proportional to the temperature difference between the hot object and the environment. So the area under a graph of the temperature is a measure of the energy loss...right? OK - so let's imagine that the kettle can heat the two half-liter loads in the time it takes to heat one full load...just as a hypothetical. If we plotted the graph of temperature against time for both experiments, we'd get either two complicated curves that go from ambient to boiling point - or one that goes to the same temperature over twice the amount of time. If we took the graph from the first experiment, cut them into one second-wide strips and interleaved them - we'd make the same graph that we got from the second experiment...so the amount of energy lost to the environment would be identical in the two cases.

However, there is a difference. At the end of the first half-liter load, the kettle itself is still hot. So when the water is added, the temperature of kettle+water will be a little higher than ambient. So the second half-load should heat up faster than the first half-liter. The energy consumption from doing that will be a little less because the slightly faster heating rate - that means that a little less energy will be lost to the environment.

So I think that it will require a little less energy to heat two half-loads than one full load...but not by much.

There was a question of whether the heating element produces more energy at different temperatures. I don't think it affects anything in the above discussion - but I think the idea that the change in resistance of the element with temperature is negligable is incorrect. Energy consumption is proportional to the resistance of the element. Higher temperatures produce more resistance - which means that more energy can be delivered at constant voltage. Electrical_resistance#Temperature_dependence says that this increase is around 0.3% to 0.6% per degree for most metals - so over maybe 80 to 90 degrees of increase, the element will consume maybe 50% more electricity (and heat the water 50% faster) near to boiling point than at room temperature. It was previously suggested that this effect would be negligable - but clearly it's not.

SteveBaker (talk) 15:29, 5 July 2013 (UTC)[reply]

Well you all are discussing about electric kettle, how about gas kettle? The kettle pot that you fill with water and put above flame? 140.0.229.26 (talk) 02:09, 6 July 2013 (UTC)[reply]

Putting an aspirin on the gum

Some people put an aspirin on the gum when they have toothache, is this practice backed by any publication? It's clear that even our skin would absorb some chemicals placed on it, but would the gum absorb even more? OsmanRF34 (talk) 13:28, 4 July 2013 (UTC)[reply]

Google works. --Jayron32 14:07, 4 July 2013 (UTC)[reply]

This link from that same google search states "but never put aspirin against the gums near the toothache, as this may burn the gum tissue". --Jayron32 18:34, 4 July 2013 (UTC)[reply]

It works in what sense? It outputs lots of 'natural remedies' results, unrelated results like gum aspirin, and relevant results for someone searching for a topical aspirin or aspirin gel, but I was asking for the usability of a normal aspirin on the gum. OsmanRF34 (talk) 14:26, 4 July 2013 (UTC)[reply]

Individual reactions to aspirin can vary. Some cannot ingest it, due to its tendency to inflame the stomach lining. It can also act as a blood thinner, which you may not want. If you've got a recurring toothache, you should see a dentist. ←Baseball Bugs ^{What's up, Doc?} carrots→ 15:20, 4 July 2013 (UTC)[reply]

Castoreum and other beaver products, rich in salicylates, have been used as topical painkillers since Roman times, as well as in many places in native North America. Wnt (talk) 00:17, 5 July 2013 (UTC)[reply]

I see no evidence for this claim, which is both dubious and unconvincing in this context (since historical uses of castoreum have included so many things, including emotional distress). -- Scray (talk) 14:50, 5 July 2013 (UTC)[reply]

Beaver mentions some sources, though most of them are not readily accessible, excepting [15]. I'm not sure if you're disputing topical salicylate, though there might be some question as to how much is actually just reaching general circulation [16] Wnt (talk) 15:19, 5 July 2013 (UTC)[reply]

wild animals and spicy food

Do any animals in the wild have a taste for spicy plants such as hot peppers, mustard-type plants and horseradish, ginger, onions, garlic, etc? Or do they all avoid these plants because they are an irritant?— Preceding unsigned comment added by 176.251.188.16 (talk • contribs)

I don't have a source on this because I read it a long time ago, but although they don't have a taste for it per se, birds are unaffected by spicyness. I read it in a book about leaving out stuff for birds to eat; coat it in spicyness to keep mammallian scavengers away, but the birds won't even notice. 176.251.188.16 (talk) 15:19, 4 July 2013 (UTC)[reply]

We hear about "grain fed cattle" as the common type and "grass-fed beef" as a pricy gourmet choice, but cows are happy to eat onions and garlic if they find them, though the milk then tastes of onion and garlic. Mad scientists are experimenting with feeding garlic to cows to reduce cow-flatulence which supposedly causes global warming: [17]. Cows will eat so much onions that they can get sick and even die. Horses and goats eat onions too: [18]. Cows do not immediately eat turnips growing in a field, but learn to like them, especially after freezing weather has increased the sugar content of the tops. This source also implies they will eat radishes: [19]. Comments at this site suggest that turkeys and parrots love very hot peppers, but deer avoid them. Here's a video of a cow eating pickles and hot peppers. Edison (talk) 16:00, 4 July 2013 (UTC)[reply]

Birds and primates will eat hot foods. Spicy foods often have attractive red colors visible to trichromatic birds and mammals. Dogs and cats and hooved mammals are neither attracted by their colors nor adapted to eat spicy foods, which may be poisonous. Humans have large livers adapted to handling plant alkaloids and so forth. μηδείς (talk) 17:34, 4 July 2013 (UTC)[reply]

The link above mentions this, but for those who haven't clicked it, one of the reasons birds ead "spicy" peppers is because they don't sense capsaicin like humans and other mammals do. So when a bird eats a habanero, it's not really percieving any spicyness - for the bird it's somewhat akin to a human eating a bell pepper. So it would be misleading to say that birds eating spicy peppers indicates that they like spicy food, because to them it's not spicy. -- 71.35.96.251 (talk) 18:56, 4 July 2013 (UTC)[reply]

I remember seeing a video on YouTube (which doesn't seem to be there any more, so you'll have to take my word) of a gull reacting negatively to a piece of bread that was spread with English mustard. It attempted to swallow the bread twice, only to very quickly regurgitate it, with much head-shaking. So it would seem that some birds can sense some types of spice. --Kurt Shaped Box (talk) 19:33, 4 July 2013 (UTC)[reply]

Mustards get their pungency from sulfur compounds, thiocyanates. Capsaicin is an alkaloid, but not a sulfur compound. Gulls are not notable for being attracted to red fruits like peppers. μηδείς (talk) 21:42, 4 July 2013 (UTC)[reply]

For what it's worth, gulls seemingly don't like wasabi either. --Kurt Shaped Box (talk) 22:09, 4 July 2013 (UTC)[reply]

Do the rest of you really put all these things in the same category? Peppers, horseradish, and ginger are "hot"; mustard, onion, and garlic are "spicy" but not "hot" (there's "hot mustard" but it has horseradish added). That's exactly why we need a separate word for the hot spices. --Trovatore (talk) 21:46, 4 July 2013 (UTC)[reply]

I might take issue with the horseradish accusation - see English Mustard. The near-identical appearance of English mustard and French's mustard is a frequent source of entertainment when unwary American tourists first encounter the former. Tevildo (talk) 22:13, 4 July 2013 (UTC)[reply]

Yep, I'd definitely say that English mustard is 'hot'. --Kurt Shaped Box (talk) 22:20, 4 July 2013 (UTC)[reply]

It's not just English Mustard. In the U.S., the mustard they serve in some Chinese restaurants is a tad piquant as well. --Jayron32 22:32, 4 July 2013 (UTC)[reply]

But "piquant" is not the same as "hot". "Hot" is a specific sensation involving thermoreception; "piquant" doesn't really seem to be any more specific than "spicy", as far as I can tell. --Trovatore (talk) 22:36, 4 July 2013 (UTC)[reply]

See Understatement. Come back if you have any further questions or do not understand what that article has to say. --Jayron32 22:41, 4 July 2013 (UTC)[reply]

If you're talking about the mustard I think you are, it has horseradish in it. --Trovatore (talk) 22:44, 4 July 2013 (UTC)[reply]

Nope. --Jayron32 22:53, 4 July 2013 (UTC)[reply]

Colman's Mustard contains "Water, Mustard Flour, Sugar, Salt, Wheat Flour, Spice, Citric Acid, Stabiliser (Xanthan Gum).". No horseradish. Tevildo (talk) 23:14, 4 July 2013 (UTC)[reply]

Better still, Colman's Mustard Powder contains _only_ mustard flour. Try putting that on your hot dogs. :) Tevildo (talk) 23:15, 4 July 2013 (UTC)[reply]

As hinted at by μηδείς, Pungency is evidently used for this purpose in some scientific publications. That said, it would be interesting to know what languages do have an established word. I know Malay and Indonesian do as I think does Thai. And I wonder if words like picante in Spanish is closer in meaning to piquant in English or "hot". Nil Einne (talk) 22:57, 4 July 2013 (UTC)[reply]

As I understand it, the "hot" sensation comes from stimulation of TRPV1 receptors, and capsaicin, piperine (from black pepper), mustard, ginger, etc all contain chemicals that activate those receptors. Looie496 (talk) 22:54, 4 July 2013 (UTC)[reply]

There are at least three deeper issues here. The fundamental epistemological issue is that humans even at the pre-scientific level perceive and categorize sensory differences long before they (if ever) explain and categorize them scientifically. The basic colors were named and categorized as warm and cool, bright and dark, long before tint and saturation were explained in scientific terms. The same with tastes such as bitter, which was known long before it was explained by the presence of basic ions. The second issue is cultural, that humans have learned to add various flavor-enhancing substances to foods; substances which they are aware of and value highly. Third is linguistic, especially that at a pre-scientific level, there is leeway and the option of emphasis. Many languages lack a specific name for brown, call pinks and oranges and purples after flowers and fruits, and identify red with "colorful" (Sp. colorado) or "beautiful" as in Russian krasnyj/krasiwyj. Yet Russian distinguishes as strictly between what we call baby and royal blue as much as we separate yellow and green, and lacks a general term "blue" that covers both tints.

Hence, in English we have the concept spice or spicy, which is broader, and covers any flavor enhancer that does not readily fall into sour, salty. or sweet. Cinnamon, bacon, cheese, and garlic can be spicy without our understanding why specifically. And hence we can categorize them with leeway. Foods like pepper that we only later learn stimulate heat-receptor nerve cells become to English speakers the stereotypical spices. Yet spicy is a broader term than hot in the way that colorful is a broader term than red. Spicy used loosely in English will translate to piquante in Spanish where it means "hot" in the English sense, but doesn't cover paprika, saffron, or cinnamon. Bilinguals learn these traps. Eventually, when a full scientific vocabulary is developed, it becomes possible to qualify translation from language to language exactly. μηδείς (talk) 04:01, 5 July 2013 (UTC)[reply]

I just watched epidoe 8 of season 4 of Breaking Bad, which has a long segment in Spanish, where one gangster goes on at length using various words for spicy to describe a Chilean's cooking, then praises it specifically for being "hot" (piquante & picoso) in the way Mexicans like it. μηδείς (talk) 23:41, 5 July 2013 (UTC)[reply]

Video on race and intelligence

WP:NOTAFORUM

The following discussion has been closed. Please do not modify it.

I found this video on race and intelligence and would like to know how scientifically accurate it is and also if you can discern a pov in it www.youtube.com/watch?v=GJ-e5XjlmZA -- 190.83.190.44 (talk · contribs) 22:54, 4 July 2013‎ (UTC)[reply]

As a simple matter, I assume every self-published video on YouTube is total and complete bullshit, unless I find identical information elsewhere in a truly reliable source, at which point I didn't need to have even seen the YouTube video in the first place. So it probably isn't even worth watching because I have zero faith that it is reliable one way or the other. If you have a specific question about specific statements in general made by the video, we can probably help provide sources to confirm or refute it. But that's the best I can offer. --Jayron32 23:09, 4 July 2013 (UTC)[reply]

I second that emotion. Intelligence is about individuals, not races. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:14, 4 July 2013 (UTC)[reply]

One of the main argument is that the races are unequal in intelligence and that political systems based on equality cannot work, they cite geneticists like Watson and his comments on African intelligence. -- 190.83.190.44 (talk · contribs) 23:20, 4 July 2013

In short, it's bogus. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:32, 4 July 2013 (UTC)[reply]

(edit conflict) Watson is a bit of a nut, and really, the fact that he is credited with discovering DNA doesn't make him anything like an expert on race and intelligence anyways. At that level, it would be like asking the guy who assembled the car's drive train at the factory the proper procedure to pass on the outside at the Daytona 500. They're vaguely related in the "both of them involve cars", but that doesn't mean that the one has anything useful to say on the other. Likewise, that Watson discovered DNA doesn't mean he has anything useful to say on racial genetics and intelligence. He's done no research in the area and isn't anything like an expert on the subject. --Jayron32 23:33, 4 July 2013 (UTC)[reply]

Should we trust random internet users talking about intelligence more than we trust Watson? OsmanRF34 (talk) 00:32, 5 July 2013 (UTC)[reply]

Nope, but we're not telling him to trust us. We're telling him to not trust that video. He should trust neither us nor the video. He should do some research in actual scientific studies, like this one. Unless you think the video is worthwhile based on the synopsis provided above. IS that what you are saying? --Jayron32 00:41, 5 July 2013 (UTC)[reply]

No, I don't believe the video is worth anything. A perfunctory view makes it even look funny, linking IQ to political positions and race (egalitarians seems to be low IQ, according to the video), explaining racial differences with the dog races analogy, linking run down boroughs with black population to African genes and more, much more. I would gladly follow your Yale link to learn more about it, but would not dismiss any author, just because he didn't do research in the field. OsmanRF34 (talk) 00:51, 5 July 2013 (UTC)[reply]

If you would not dismiss any author, how do you discern what is believable or not? Your statement seems to imply that you believe everything everyone says on every topic without exception, and that cannot be what you mean here. Do you really mean to say you would accept Watson's analysis of every topic, from who is likely to win the EPL next year to which stocks to purchase to what the weather is going to be like in Kalamazoo next week? Please elaborate on the universal omniscience of all people you seem to be proposing when you say you would not dismiss any author. --Jayron32 01:15, 5 July 2013 (UTC)[reply]

I would not dismiss any author, upfront. If you check several sources, you'll come to some contradiction down the road when you confront one theory with the others, and you'll have to choose if you dismiss your old theory or if you keep it. However, just because Watson didn't research IQ, it doesn't follow that he won't be able to say anything about intelligence (I don't know if he has something to say, but leave that door open). Smaller people than him have already contributed to science although they didn't have any formal education (although probably not through YouTube).OsmanRF34 (talk) 01:39, 5 July 2013 (UTC)[reply]

I agree 100%. Finding a YouTube video that supports some scientific conjecture is almost certain proof that it's wrong! Forget YouTube videos - they prove absolutely nothing. You really need to look at serious scientific studies in boring, dusty, old journals.

Anyway, why is it that we're suddenly getting so many questions about race in the last couple of weeks?

SteveBaker (talk) 23:27, 4 July 2013 (UTC)[reply]

Take it easy with YouTube. There are some intelligent channels in there: Bad Astronomy, YouTube EDU, Ted Talks. That obviously doesn't mean that apparently all fringe theories are not well represented there. OsmanRF34 (talk) 00:32, 5 July 2013 (UTC)[reply]

But is the video and its view accurate to scientific fact? — Preceding unsigned comment added by 190.83.190.44 (talk • contribs) 23:48, 4 July 2013 (UTC)[reply]

No. ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:23, 5 July 2013 (UTC)[reply]

Which bit of 'it's bogus' did you not understand? It's a pile of racist, anti-scientific codswallop. AlexTiefling (talk) 23:53, 4 July 2013 (UTC)[reply]

Note: the video is 3 hours and 40 minutes. Are we expected to watch it and come back here to comment? OsmanRF34 (talk) 00:32, 5 July 2013 (UTC)[reply]

The OP gave a synopsis above where they stated "One of the main argument is that the races are unequal in intelligence and that political systems based on equality cannot work" Which saves me from having to watch three+ hours of unmitigated bullshit, because one sentence of unmitigated bullshit seems to say enough to be refuted out of hand. --Jayron32 00:35, 5 July 2013 (UTC)[reply]

Yep. HiLo48 (talk) 00:58, 5 July 2013 (UTC)[reply]

Yep what Hilo48? I fail to see what you are yepping to.OsmanRF34 (talk) 01:01, 5 July 2013 (UTC)[reply]

I am inclined to say that the OP is perpetrating link spam and soap-boxing, (very) thinly disguised as a question. Is there an actual request for scientific reference? If not, I recommend we close this and move side-discussion to the talk-page. Nimur (talk) 02:34, 5 July 2013 (UTC)[reply]

I watched the first 20 minutes of this video. Familiar with the situation from the viewpoint of Boas and Gould and those they criticize, the video's author makes no obvious mistakes, although his POV is clear. I am not about to listen to the whole video. This page is not the forum to debate the claims. But readers should not assume that this being closed is weight in favor of its falsehood. μηδείς (talk)

Gould's flaws are well-known, but I wouldn't say this fact demolishes non-racist world views. Gould's is barely a seminal work. I still wait to see a race=>IQ argument that defines races and IQ, explains how you measure belonging to one race and how you measure IQ (independent of environmental factors). The parts of the video that I saw were of a rather convoluted nature, presenting evidence out of nowhere, confusing up being equal to being the same, attacking what an undefined group of people, called "they" think or want. OsmanRF34 (talk) 11:29, 5 July 2013 (UTC)[reply]

Well I sometimes do statistics using fuzzy measures so precise definitions don't bother me too much, but what's there so far provides no evidence of any significant difference due to genetics between countries. Deprivation is easy to understand but the thing I have really been surprised by is the enormous effect people's expectations and peer pressure have on performance. Dmcq (talk) 14:02, 5 July 2013 (UTC)[reply]

I'd like to see some of those white supremacist degenerates take an IQ test constructed by someone like the Maasai people and see how well they would do. ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:35, 5 July 2013 (UTC)[reply]

Yep, an IQ test based in something like distinguishing linguistic tones would do the trick. It would come out that Africans are the most intelligent, followed by Chinese and Vietnamese, I suppose. "If you judge a fish by its ability to climb a tree, it will live its whole life believing that it is stupid." OsmanRF34 (talk) 16:45, 5 July 2013 (UTC)[reply]

July 5

Electricity

when electric charges move in close loops, it produced what type of force — Preceding unsigned comment added by 196.46.246.59 (talk • contribs)

When the reference desk gets people's homework questions, it forces them to do it themselves. Try Electric current. 202.155.85.18 (talk) 06:01, 5 July 2013 (UTC)[reply]

...or Coil. SteveBaker (talk) 14:41, 5 July 2013 (UTC)[reply]

Can magnetic fields be like a laser?

Or at least, can be focus a magnetic field? I am aware that solenoids are somehow a way of concentrating a magnetic field, but it would still fall off at a rate of 1/r^3 as the distance increases. OsmanRF34 (talk) 11:43, 5 July 2013 (UTC)[reply]

You are making the common mistake of confusing laser light with collimated light; you are conflating focus with beam collimation. You can construct a device to collimate a magnetic field, but a static field cannot propagate as a wave, and the static magnetic field cannot be amplified as part of a lasing process. A laser operates to amplify light using stimulated emission. Nimur (talk) 14:55, 5 July 2013 (UTC)[reply]

Fern spore range

How far can ferns fire their spores, with a catapult like this [20]? I'm just interested in a ball park figure here, but can't find a number online. Cheers, Aaadddaaammm (talk) 12:20, 5 July 2013 (UTC)[reply]

The paper (PMID 22422975) says that the spores are ejected with a velocity of up to 10 meters per second. Taking into account air resistance, that's probably enough to hurl them a few feet -- although even a slight amount of wind could carry them much farther. Looie496 (talk) 14:38, 5 July 2013 (UTC)[reply]

I don't think we can answer this one.

According to our article, Polypodium aureum, the spores are mostly carried by the wind...the "catapult" may only be there to launch the spores far enough to get away from the wind-shielding effect of the frond it's attached to. At any rate, even with completely still air, the distance would depend crucially on the height above the ground and the angle at which it was launched - both of which are unknown. Even knowing the speed at which the spore is launched - the range is unknowable without a LOT more information about the nature of a specific launch event.

My guess is that since the spores are light, they could easily float in the wind for miles - that's true for the wind-born spores of many plants and fungi. SteveBaker (talk) 14:39, 5 July 2013 (UTC)[reply]

Many people study dispersal kernels of plants. That's a redlink, but see also Biological_dispersal#Quantifying_dispersal. I'd try searching google scholar for /dispersal kernel fern/ to get a feel for what's been discovered through empirical tests and theoretical models. SemanticMantis (talk) 16:08, 5 July 2013 (UTC)[reply]

Tension

I seem to have got into a muddle about this. If a string is in equilibrium, and there is a force F pulling in one direction at one end and a force F pulling in the opposite direction at the other end, then each point of the string has a force of F one way plus F the other, so why is the tension not 2F? Or is it? 86.176.210.160 (talk) 13:52, 5 July 2013 (UTC)[reply]

Think of it like this: That situation is identical to one in which a string is tied to a fixed object at one end with a force of F on the other because at the fixed end of the string, every action has an equal and opposite reaction. SteveBaker (talk) 14:31, 5 July 2013 (UTC)[reply]

Great answer. Often this problem is seen in finer clothing: a strongman stands on a runway between two planes trying to take off in opposite directions, with each hand holding a handle at the end of a rope tied to each plane. Surely this is harder than holding back just one plane with one comparable handle in one hand and one mounted to a wall in the other, right? :) (Of course, part of why our intuition on this is wrong is probably that we simply assume some kind of bracing, even when the premises of the problem rule it out) Wnt (talk) 15:11, 5 July 2013 (UTC)[reply]

Thanks, but I don't get it. That answer is just restating the same question. If a string is tied to a fixed object with a force F at the other end then there must be an opposite force F at the fixed end, just like I posited, otherwise the string would move. I understand that part fine. What I don't understand is why, when at each point on the string there is a force F in one direction and an equal and opposite force F in the other, why the tension is not F + F, or 2F. 86.176.210.160 (talk) 17:04, 5 July 2013 (UTC)[reply]

More to the point, "Why isn't the tension F + (-F) = 0", because forces are vectors, and forces of equal magnitude and opposite direction will exactly cancel out!

The descriptions above were all very good, qualitatively; but they have missed out on one piece of the explanation, which is that we define tension relative to the force that we can measure; and we can measure it only at the boundary condition of the string. We could have defined tension to equal twice the static force at the boundary condition; or π times the static force at the boundary condition; but those definitions don't help make the mathematical model any simpler.

If you should ever want to pursue a more advanced study of strings using calculus, you will use a new mathematical model that replaces the string tension - which is a scalar quantity that is just a statistical average over the whole string - and replace it with an infinitesimal restoring force at every point on the string, whose direction and magnitude is related to the infinitesimal deviation from a perfectly taut string; and whose period of oscillation is determined by the infinitesimal mass density of the string and the elasticity of the string. And you will have to integrate over the infinite number of infinitely-small strings to calculate the force on each differential element; the only constraints are the physical realities like the string's mass and its propensity for elastic deformation. That is how we mathematically derive the force on a piece of material that is inside the string - we can't directly measure it, because if we cut the string to put in a measurement tool, by definition we'd only be measuring the force on the end of the string we just cut! Suddenly a simple, scalar quantity that represents "tension" is looking pretty friendly, especially when it works out so well for statics! Nimur (talk) 17:24, 5 July 2013 (UTC)[reply]

So, defining tension as F is just a convention? I disagree, by the way, that defining it as π times the force at the end makes as much sense as defining it as twice the force at the end, but that's a secondary issue... if it's just a matter of definition then my main concern goes away. 86.176.210.160 (talk) 17:30, 5 July 2013 (UTC)[reply]

It would not be the first time physicists threw a pi at the universe just to make one specific form of their equation look prettier. Nimur (talk) 17:32, 5 July 2013 (UTC)[reply]

Well, think of how you measure tension, e.g. with a spring scale. You can attach the spring scale to one end of the line, and measure off the reading of the force you're putting on that end only relative to the force of a kilogram weight under Earth gravity. Or, you can cut the line and tie the spring scale in the middle of the line with some rope on either side. Either way, the spring scale itself has two ends (won't stay still without them!), and it measures the same result. For that matter, notice that even with your kilogram weight the same duality applies: the Earth is pulling down on it with that force, so why isn't it moving? Because the Earth is falling toward the weight's far punier gravitational field, but with far more mass, to have the same reaction as the spring! So ultimately there are two "ends" to any force you could put on something, provided it isn't actually accelerating. Wnt (talk) 21:12, 5 July 2013 (UTC)[reply]

polymers

Are most or all polymers solid at room temperature?--99.146.124.35 (talk) 17:46, 5 July 2013 (UTC) 10–1000 g/mol for simple chemical compounds;[reply]

You might want to read about melting polymers. It's a little bit unusual to think about a fluid of polymers. Nimur (talk) 17:48, 5 July 2013 (UTC)[reply]

Also, do most molecules with molar masses equal to or greater than 400g/mol tend to be solids at room temperature? What about all molecules >1000g/mol?--99.146.124.35 (talk) 18:11, 5 July 2013 (UTC)[reply]

Polymers occupy a region of solids between that of molecular compounds and network solids. Compounds composed of small molecules have relatively weak intermolecular interactions, and so tend to melt rather readily, often near or even below room temperature. At the other end of the spectrum, network solids are composed of massive networks of very strong covalent bonds (the same type and strength of bond holding individual molecules together in a molecular compound like water: that is the force holding the "H" to the "O" and not the force holding the individual H₂O molecules together, which is quite weak comparitively). These network solids like diamond and carborundum don't really have proper "melting" points as they don't really "melt" per se. They do break up into smaller bits, but this is really more of a Chemical decomposition than proper melting. Polymers lie somewhere between these two types of substances. Polymers are composed of discrete molecules, unlike network solids, but the molecules are so large and intertwined that they don't readily break apart as a simple molecular compound does (like water) so they don't really have a discrete melting point, rather they have a temperature where they get soft enough to flow, similar in some ways to the Glass transition that occurs in glass, which is also a type of material that doesn't fit neatly into the elementary school "solid-liquid-gas" classification scheme. --Jayron32 18:58, 5 July 2013 (UTC)[reply]

Affinity constants

I've lost track of the scale of association/dissociation constants for medications. There are so many. For instance, the binding profile of risperidone is:

D1 dopaminergic receptors (Ki = 536 nM)[20] D1 receptor antagonist D5 receptor antagonist D2 dopaminergic receptors (Ki = 3.13 nM) D2 receptor antagonist D3 receptor inverse agonist D4 receptor antagonist

This information comes from a wikipedia article on the medication.

My questions are: Which affinity is tighter (stronger): Ki = 3.13 nM for D2 receptors or Ki = 536 nM for D1? I think the lower number represents the stronger bond, correct?

Also what does "i" stand for?

Thanks, - Alex168.178.74.86 (talk) 20:34, 5 July 2013 (UTC)[reply]

Lower values indicate stronger binding. You may find Receptor_antagonist#Affinity and IC50#Competition_binding_assays useful. The dimension of K_i is a concentration; one crude way to remember this sort of thing is that the K_x is the concentration (of something) at which its x is half-maximal. While this mnemonic may be imperfect, it's pretty useful. In this case, K_i is the concentration of an inhibitor (or binding antagonist/competitor) at which inhibition (binding) is half-maximal. With this relationship in mind, it is intuitive that 100-fold lower K_i would indicate a much more potent inhibitor. -- Scray (talk) 21:38, 5 July 2013 (UTC)[reply]

Here is a paper with some useful math, though the online calculator to which it links seems to be down. -- Scray (talk) 21:42, 5 July 2013 (UTC)[reply]

Thank you for the comprehensive answer. - Alex168.178.74.86 (talk) 21:53, 5 July 2013 (UTC)[reply]

Is Neptune habitable?

This does have the sound of a stupid question, yet... according to our article, Neptune has a reasonably comfortable equatorial gravity around 1.14 g. It has a core at up to 5,400 K, lying under a vast mantle which is variously described as "icy", "hot, highly dense fluid", and "water-ammonia ocean". True, at Earth atmospheric pressure its temperature is about -346 degrees Fahrenheit. [21] But so what? Lots of stuff on Earth lives at more than a few atmospheric pressures.

The problem is, I'm seeing stats in thousands of degrees for some unspecified point in the mantle, which is apparently 10GPa of pressure or (much much) more; but not quickly finding statistics for what the temperature is at pressures more like 1 MPa (Mariana Trench level). Can someone point at a pressure-temperature curve?

I don't know how feasible it is to try to test (or even breed) abyssal Earth lifeforms at super-Mariana pressures, in the presence of ammonia and other strong reducing agents... Wnt (talk) 21:58, 5 July 2013 (UTC)[reply]

The gas giants don't have surfaces to inhabit. I assume that means uninhabitable in your book. μηδείς (talk) 23:38, 5 July 2013 (UTC)[reply]

He probably asks whether there is liquid water between this gas surface and the core. OsmanRF34 (talk) 23:41, 5 July 2013 (UTC)[reply]

Check [| Liquid Water Oceans in Ice Giants]. If there is liquid water on Earth somewhere, there there is life. So, if there is liquid water in Neptune, then, life could be possible. However, liquid water oceans are not very probable there. So, try better a satellite of Saturn or Jupiter for a better chance. OsmanRF34 (talk) 23:41, 5 July 2013 (UTC)[reply]

Potential energy stored in a capacitor

I'm trying to derive the equation $U=Q\cdot V={\frac {1}{2}}\cdot C\cdot V^{2}$ from what I know about electrostatics. I know that $C={\frac {Q}{V}}$ , so I tried turning it into an integral like $C={\frac {\operatorname {d} \!Q}{\operatorname {d} \!V}}\Rightarrow \operatorname {d} \!Q=C\operatorname {d} \!V\Rightarrow \int \operatorname {d} \!Q=\int C\,\operatorname {d} \!V\Rightarrow Q=C\cdot V$ , but that doesn't help me to derive the equation for energy potential. — Melab±1 ☎ 00:53, 6 July 2013 (UTC)[reply]

You need to bring energy into it. You have only related charge, voltage and capacitance. See whether you can bring in what you know about the power conveyed by an electric current. — Quondum 01:46, 6 July 2013 (UTC)[reply]

@@ Line 153: / Line 153: @@
 : There was a question of whether the heating element produces more energy at different temperatures.  I don't think it affects anything in the above discussion - but I think the idea that the change in resistance of the element with temperature is negligable is incorrect.  Energy consumption is proportional to the resistance of the element.  Higher temperatures produce more resistance - which means that more energy can be delivered at constant voltage. [[Electrical_resistance#Temperature_dependence]] says that this increase is around 0.3% to 0.6% per degree for most metals - so over maybe 80 to 90 degrees of increase, the element will consume maybe 50% more electricity (and heat the water 50% faster) near to boiling point than at room temperature.  It was previously suggested that this effect would be negligable - but clearly it's not.
 : [[User:SteveBaker|SteveBaker]] ([[User talk:SteveBaker|talk]]) 15:29, 5 July 2013 (UTC)
+Well you all are discussing about electric kettle, how about gas kettle? The kettle pot that you fill with water and put above flame? [[Special:Contributions/140.0.229.26|140.0.229.26]] ([[User talk:140.0.229.26|talk]]) 02:09, 6 July 2013 (UTC)
 == Putting an aspirin on the gum ==