Wikipedia:Reference desk/Archives/Science/2011 October 16

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October 16

termodinamika

artikel tentang termodinamika ke nol dan suhu absolut — Preceding unsigned comment added by 125.164.119.15 (talk) 04:22, 16 October 2011 (UTC)

Google Translate says this is Indonesian for "articles about thermodynamics to zero and the absolute temperature". Looie496 (talk) 04:29, 16 October 2011 (UTC)

Lihat halaman ini dalam Wikipedia bahasa Indonesia: Termodinamika ..-- Obsidi♠n Soul 04:38, 16 October 2011 (UTC)

"See this page in..." as per Google translate. Right? So, what's the Indonesian for "this is the English wikipedia"? :) ←Baseball Bugs ^{What's up, Doc?} carrots→ 09:27, 16 October 2011 (UTC)

Something like: "Ini ialah wikipedia bahasa Inggris". Google translate confirms it's probably okay. Nil Einne (talk) 14:08, 16 October 2011 (UTC)

Kelvin / Nol mutlak. ~AH1 ^(discuss!) 21:51, 16 October 2011 (UTC)

best glue for specific materials

I have an item that is made primarily of "reinforced polycarbonate, mirror polished and coated to protect against scratches and daily use" and I need to know what the best glue to attach it to either micrifiber or suede would be (both of the two items I would like to glue together were expensive, and I don't want to ruin them)? Also, a seperate part of the item is made from "brushed, anodized aluminium" and I need to know which would be the best glue to attach it to leather? Thank you... also, I assume here in the science section is the best place for this question, but if it belongs in misc., let me know and I'll ask there. — Preceding unsigned comment added by 72.175.132.243 (talk) 09:06, 16 October 2011 (UTC)

Do you need a strong bond that can be removed without damage to any of the materials? I've been trying to think of an adhesive that would work for all five materials without damage. The only suggestion I can think of is Sticki-Dotsbut I'm not sure how strong they would be on suede, and I don't know whether they would peel off your polycarb without affecting the coating. (Any contact adhesive will serve your purpose if you don't mind damage to your suede, leather and microfibre, but that's not what you asked.) Dbfirs 07:44, 17 October 2011 (UTC)

You need leathercraft cement and even then don't get your hopes up. And read the directions, it will probably want you to clean and roughen (smooth side) or shave (rough side) the suede and then have a way to let it set for some absurd length of time; possibly days if I remember right. So you might also need one or more vices, clamps, splints, rubber bands, etc. Dualus (talk) 09:45, 17 October 2011 (UTC)

cholangiocarcinoma advanced stge IV

I would like to Know various kind of Treatment for cholangiocarcinoma stge IV Using Alopathym Homeopathy or Siddha Medicine - help me — Preceding unsigned comment added by Ssvaluers (talk • contribs) 09:38, 16 October 2011 (UTC)

Cholangiocarcinoma is a serious disease, and that article stresses the importance of conventional treatments. Homeopathy has different meanings: traditionally it referred to the approach of using a medicine that causes symptoms similar to the disease treated, which has some tenuous philosophical relevance; but more recently it has been used to describe a system of giving people almost infinitely diluted medicine (like as not plain tap water, since there's no medical difference) - it is absurd to view such as a treatment. Allopathy originally meant giving a medicine with opposite symptoms to the disease, but it too has been redefined in usage to mean, more or less, "conventional medicine". Siddha medicine is unfamiliar to me; according to the article it is like Ayurvedic medicine, a traditional pharmacopoeia of remedies. Such traditional remedies are occasionally harmful, sometimes useful ... rarely miraculous, but they are a valuable option to research, though of course a speculative or unconfirmed treatment is not as good as a known one. For specific treatments PubMed offers an important resource, indexing over 6000 articles about the disease.^[1] Amazingly, clinicaltrials.gov indexes 114 clinical trials worldwide, mostly in the U.S. and Europe.^[2] Wnt (talk) 11:50, 16 October 2011 (UTC)

Looking at some top hits for "cholangiocarcinoma and ayurvedic" (which I will not call reliable sources but are a starting point for discussion) I'm seeing stuff like "The Ayurvedic treatment of CC is aimed at treating the tumor, controlling the symptoms, preventing a blockage of bile flow, infection and other complications and prolonging life. Ayurvedic medicines like Arogya-Vardhini, Triphala-Guggulu, Kanchnaar-Guggulu, Punarnavadi-Guggulu, Chandraprabha-Vati and Bhunimbadi-Qadha are used to treat the actual tumor. Herbal medicines like Kutki (Picrorrhiza kurroa), Sharpunkha (Tephrosia purpurea), Kalmegh (Andrographis paniculata), Punarnava (Boerhaavia diffusa), Karela (Momordica charantia), Trikatu (Three pungent herbs), Pippali (Piper longum), Marich (Piper nigrum), Mandukparni (Centella asiatica), Haridra (Curcuma longa) and Daruharidra (Berberis aristata) can also be used for this purpose. Most of these herbal medicines also reduce inflammation and prevent infection. Medicines like Yashtimadhuk (Glycyrrhiza glabra) and Amalaki (Emblica officinalis) can prevent or treat complications like fistula formation" (Wikipedia formally blacklists this source //ezinearticles.com/?Cholangiocarcinoma---Ayurvedic-Herbal-Treatment&id=2707129 but we're just sniffing around here for ideas) Now looking at this, note that ordinary black pepper and long pepper are on the list, which gives us an idea of the level of potency of the herbs recommended. Still, guggulu is an exotic herb to Western eyes (and now, to the IUCN) and it comes up on the list three times, so let's have a look at "Commiphora cancer" in PubMed: [3] We get out some stuff that looks like no real help - a compound from it may interfere with prostate cancer by blocking androgens, so while the other article about apoptosis in prostate cancer cells sounds interesting, it is of no help here. (besides, of course, we have no idea how much you'd need, and likely the conventional antiandrogenic drugs are more potent). Still, articles about guggulsterone like this are encouraging to see; also [4] and many others from that search. (Though at best these sound like ways to slow down the tumor's growth, not really cure it). Ultimately, however, in the absence of conclusive medical results, people have to look over the evidence themselves and decide what is worth hoping for. Wnt (talk) 12:25, 16 October 2011 (UTC)

Self discipline

Are people, especialy young people, with good self discipline born with it (i.e.genetic), or do they gain the skill through life experiences? Thanks.Clover345 (talk) 12:35, 16 October 2011 (UTC)

Rewards seem to reinforce self-discipline. 88.11.244.183 (talk) 15:40, 16 October 2011 (UTC)

For some youth, rewards alone do not encourage self-discipline. Please refer to the following articles: self-discipline, self control, maturity (psychological), self-esteem, martial art, psychological resilience, corporal punishment, youth subculture, conscientiousness, Bando and Sudbury school. ~AH1 ^(discuss!) 21:43, 16 October 2011 (UTC)

Have a look at Nature vs nurture. The answer to most questions like this is that it is neither completely one or the other (innate or learned), but falls somewhere in between. You can't really say what is or isn't the case in a particular scenario, just what's more likely the case in general. If you are specifically interested in self discipline, you probably want to find a twin study that investigated conscientiousness, I did just a very quick search but nothing jumped out at me. Vespine (talk) 22:11, 16 October 2011 (UTC)

Let's get real: Could we really survive a nuke inside a refrigerator?

Indiana Jones appeared to: http://www.youtube.com/watch?v=uEphsqDIF4Q&feature=related

What testing or other scientific basis backs up the allegation that a man could survive a nuclear blast locked inside a fridge?

How would a fridge made in 2011 stack up to a fridge made in 1951? How far away would the origination of the nuke blast need to be, in order for the refrigerator to withstand the blast and preserve the contents within? --70.179.174.63 (talk) 12:51, 16 October 2011 (UTC)

The fridge surviving the blast is not implausible — it's not too hard to make it so that hard, heavy, inflammable things are propelled by blasts as opposed to being vaporized by them. (See Operation_Plumbbob#The_first_nuclear-propelled_manmade_object_in_space.3F). But that is entirely different from a human being being able to survive inside of them. He would have been reduced to jelly by the forces put on his body, battering around in an old fridge. I'm not sure there's any safe distance for that, if he's not really strapped into it. --Mr.98 (talk) 14:39, 16 October 2011 (UTC)

How Indiana Jones 4 Should Have Ended - YouTube "AAAAaaAAAAaaaaAAAaaaaarggggh, I think I have broken every bone in my body!" --Enric Naval (talk) 15:06, 16 October 2011 (UTC)

Material technology has improved and, like modern vs. '50s cars, modern fridges don't need to be as sturdily built with as much metal (and are certainly not lead-lined! Except for ones like this.). Were normal '50s fridges really lead-lined? Clarityfiend (talk) 20:12, 16 October 2011 (UTC)

Why does this remind me of Romans, their lead-lined aqueducts, and their insanity? :P -- Obsidi♠n Soul 17:11, 17 October 2011 (UTC)

See [5]. I don't think I've seen this movie, but note for reference that a man survived at Hiroshima almost at ground zero (but it was an airburst, not sure if this was). Wnt (talk) 14:48, 19 October 2011 (UTC)

On a side-note, how fast should a car be to outrun a blast?

I pity the poor Soviet agents in that car. (Whatever the make & model was.) How fast would a car need to be in order to outrun a nuke blast like the poor commies attempted to? What car(s) would reach that speed, and in how many seconds from a full stop? --70.179.174.63 (talk) 12:51, 16 October 2011 (UTC)

The blast wave of a nuclear explosion starts at much faster than the speed of sound while still inside the fireball, but quickly reduced in speed to "only" that of the speed of sound. The intensity of the blast decreases approximately as a square of the distance. If you watch footage of nuclear explosions you'll see that the really nasty effects of the bomb cover their affected area in well under a minute. I really don't see it feasible to "outrun the blast" unless you are in something like a jet and you are already in transit when it occurs, and you're right on the edge of the harmful radius anyway. But this is just a qualitative assessment. (And overall lesson here is not to take Indiana Jones as the authority on anything related to nuclear weapons effects.) Instead of slamming your foot on the gas, you'd be better off taking cover and shielding your face (from glass or projectiles). Whether that will help or not would be a matter of distance and luck, but it would be more productive than trying to use your one second or two of decision-making time before the blast hits you to escape, which won't work at all. --Mr.98 (talk) 14:39, 16 October 2011 (UTC)

If you are outside the area that are directly hit, you could outrun the blast with a rocket. Provided that you keep the acceleration below the deadly threshold at 50 G. As for asteroid impacts this is a more likely scenario. So possible provided you have some basic luck and a sufficiently fast rocket. Electron9 (talk) 14:31, 17 October 2011 (UTC)

You'll have more time to outrun a blast like this one :) . Count Iblis (talk) 20:00, 16 October 2011 (UTC)

Power generation from Earth Magnetic Field

Dears

As you are fully aware we are living on a huge storage of energy bank which we called Earth magnetic field,

My Question is:

Is any "Power generator" invented which is producing energy with Earth Magnetic Field?

Thanks for your kind attention and also corporation.

Best regards, H.Vahedi — Preceding unsigned comment added by H.vahedi (talk • contribs) 13:05, 16 October 2011 (UTC)

It's far too weak to be useful for that purpose. Looie496 (talk) 16:39, 16 October 2011 (UTC)

Even a satellite traveling in Earth's orbit would not be able to use the Earth's magnetic field unless it was able to be connected to a stationary object or another satellite. Even a brushless alternator would require connection to another satellite in a different orbit. Dualus (talk) 18:01, 16 October 2011 (UTC)

This is Ref Desk question #2376. It was last discussed here. --Heron (talk) 18:58, 16 October 2011 (UTC)

Wikipedia is not a corporation. :) ~AH1 ^(discuss!) 21:35, 16 October 2011 (UTC)

The answer linked to by Heron referenced observations of "telluric" or "earth" currents of perhaps 1.2 volts per kilometer at times, as during solar storms, or from geomagnetic activity. On long cables and telegraph lines, hundreds of volts have been measured, and as much as 2.5 amperes produced. But it comes and goes, and is not all that powerful a source compared to a normal generator, a tidal or geothermal plant, wind generators or solar panels. This was electricity from within the earth or from solar activity which was a nuisance on lines built for other purposes, and perhaps a purpose built energy collector could be more predictable. It seems unlikely to be an economic source of energy compared to the other ones I listed. Edison (talk) 19:18, 16 October 2011 (UTC)

This topic reminds me of the tesla coil. ~AH1 ^(discuss!) 21:35, 16 October 2011 (UTC)

You may find Electrodynamic tethers interesting. They don't actually generate electricity from the magnetic field, but use it to convert electricity into motion. --Tango (talk) 22:19, 16 October 2011 (UTC)

To please AH1, I'll try to be more specific. This paper calculates the energy stored in the Earth's magnetic field to be 10^17 J, or a gigawatt-year, so it's pretty feeble really. Trying to extract that energy wouldn't be worth the effort, and could lead to some extremely unpleasant consequences: not just total extinction, but a film as bad as this. --Heron (talk) 09:16, 17 October 2011 (UTC)

A "gigawatt year" actually sounds like a lot of energy. That would be approximately a large nuclear plant's continuous output. It would sell for $400,000,000 a year or so wholesale. Edison (talk) 01:56, 18 October 2011 (UTC)

Yeah, but when you've used up all the energy, you have to wait for the Earth to build a new field, if it can be bothered. I'd like to know how long that would take. --Heron (talk) 18:20, 18 October 2011 (UTC)

Is antiviral prophylaxis possible?

Antibiotics are sometimes used prophylactically before dental procedures. Can something similar be done for viral diseases? --98.114.41.194 (talk) 14:10, 16 October 2011 (UTC)

Yes, even for preventing a HIV infection shortly after a possible contact with the virus 88.11.244.183 (talk) 15:38, 16 October 2011 (UTC)

::I mean, you can use antiretroviral drugs, which are not antibiotics, to treat a potential viral infection prophylactically.. 88.8.75.87 (talk) 20:59, 16 October 2011 (UTC)

Please see vaccine. Dualus (talk) 17:56, 16 October 2011 (UTC)

Vaccine is not relevant here, AFAIK. The OP is interested in antibiotics. 88.8.75.87 (talk) 20:59, 16 October 2011 (UTC)

There are no "antiviral" antibiotics, except to the extent that they reduce bacteriophage attacks on beneficial gut flora. Dualus (talk) 21:28, 16 October 2011 (UTC)

No there is no antiviral antibiotics. The OP wants then the "something similar". For me that means antiviral drugs. — Preceding unsigned comment added by 88.8.75.87 (talk) 21:56, 16 October 2011 (UTC)

Try article, antiviral medicine and a UK department of health publication during the 2009 flu pandemic. ~AH1 ^(discuss!) 21:31, 16 October 2011 (UTC)

Prophylactic antiviral therapy can be given for some specific viruses - for example, AZT given to pregnant mothers to prevent infection of the child during birth. (more generally there is post-exposure prophylaxis, sort of an oxymoron but nonetheless a life saver) Wnt (talk) 11:20, 17 October 2011 (UTC)

"Post-exposure prophylaxis" isn't really oxymoronic; one can also prophylax before exposure (indeed, studies are underway regarding the use of anti-retrovirals as pre-exposure prophylaxis in high-risk populations; also, most commonly used vaccines are given as pre-exposure prophylaxis). And, of course, some vaccines are also used as viral post-exposure prophylaxis, such as the rabies vaccine. - Nunh-huh 23:10, 17 October 2011 (UTC)

To clarify, prophylaxis using antiviral drugs is what I have in mind. In the case of the antibiotics given before dental procedures, I think they are broad-spectrum ones. I was wondering if it's possible to reduce the risk of many types of viral infections without having to target each one individually. Thanks for all the answers so far. --98.114.41.194 (talk) 12:03, 17 October 2011 (UTC)

In general I would say that it is not very feasible to protect against many viruses at once. There are many viruses which are simply unrelated to one another. Their most common component is DNA polymerase and/or RNA-dependent RNA polymerase and/or reverse transcriptase activity, which makes them vulnerable to nucleotide analogs. That's why very soon after the AIDS epidemic was announced on the news, there were reports that showed us a kit of about 200 drugs and said "the cure will probably come out of this" (after almost ten years of piddling around in model organisms and then finally deciding who was able to get to the lab with a human first and patent the obvious drugs for himself...) In a hypothetical situation with a truly unknown new lethal virus I can picture someone taking HIV drugs and having a Hollywood ending where he comes out alright. But outside of Hollywood, you need an intensive care unit and perhaps a coroner. Wnt (talk) 22:26, 17 October 2011 (UTC)

How about IVIG? I am pretty sure I have heard of that being used for accidental exposures like needle sticks for healthcare workers in hospitals. μηδείς (talk) 23:00, 17 October 2011 (UTC)

top 1000 Fan pages on Facebook

How do you find the top 1000 Fan pages on Facebook ? — Preceding unsigned comment added by Wrhump (talk • contribs) 16:27, 16 October 2011 (UTC)

Here is a dated version, from 2008. ~AH1 ^(discuss!) 21:29, 16 October 2011 (UTC)

Neutrinos not faster than light: Do GLONASS and GALILEO have dithering, too?

Several reliable sources e.g. [6] and [7] (arxiv pdf) have claimed that the OPERA project detection of apparently faster than light neutrinos was actually due to a measurement error caused by the convoluted relativistic correction in GPS, which allows for tactical "dithering" to avert, for example, a hostile cruise missile strike. Does anyone know whether GLONASS and Galileo (satellite navigation) have tactical dithering too? Dualus (talk) 21:20, 16 October 2011 (UTC)

Before others ask it: what do you mean by "tactical dithering"? I ask because the term neither appears in any of those articles, nor does it appear to be a common phrase, nor is it a terribly clear phrase (do you mean dithering as in "wasting time" or "pixellate"?), nor is it clear what a cruise missile has to do with any of the above. I think if you clarified those points you will get somewhat more clear responses from us... My reading of the articles does not enlighten me at all as to what you're asking, I'm afraid. --Mr.98 (talk) 02:00, 17 October 2011 (UTC)

More like pixellation than wasting time, but I suspect both. They said GPS dithering was off. But why would they just waste something like that when it's such a valuable military asset? Dualus (talk) 02:45, 17 October 2011 (UTC)

I'm confused, are you referring to selective availability? This is what the utexas source appears to be referring. The reasons it was added, the reasons it was temporarily or experimentally (at the time) turned off as well as the fact future satellites will lack the capability are all mentioned to some extent in the aforelinked article, which is linked from our main Global Positioning System article (which also briefly mentions the reasons). There's no need for any big conspiracy theories about waste. The original sources appear to be referring to something else which has nothing to do with selective availability (it would be extremely embarassing for the people involved in those sources if they were confused about something a simple check of the wikipedia articles would have cleared up). Nor anything to do with some intentional error added by the US government. Instead it simply seems to refer to an error in the OPERA team's calculations from failing to take something in to account (which was after all one of the reasons they went public, to see if anyone could think of anything they missed), although I don't understand the physics involved well enough to otherwise comment on whether they may be right or wrong (but the comments below don't sound promosing for them). Nil Einne (talk) 08:11, 17 October 2011 (UTC)

The beginning statement is partially true. The sources linked don't make any claims of convoluted correction. They point out that the original measurement corrected for relative time between the neutrinos and Earth, but did not correct for the relative time between the GPS satellites and Earth (or the GPS satellites and the neutrinos) and the relative speeds of the two satellites to one another. On to the "convoluted relativistic correction", the U.S. government restricts use of GPS as guidance for missiles (except for the U.S. military, of course). Ever since that restriction was revealed, there has been reports that GPS doesn't work if you are military. It, somehow, claims you are somewhere else so you can't know where you are (or something else weird). Anyone who has used GPS knows that this claim is false. Civilian GPS is very accurate. So, to answer the question: neither GLONASS or Galileo have some sort of scrambling or randomness just to screw with civilians. -- kainaw™ 02:17, 17 October 2011 (UTC)

What a relief? Dualus (talk) 02:45, 17 October 2011 (UTC)

What are your reliable sources? The International Business Times and the Physics arXiv Blog? I doubt this preprint is correct because the claimed explanation makes no sense on the face of it. It sounds like it was written by someone who doesn't understand relativity. The author is not a physicist and has only one published paper on the arXiv, which appeared in the Journal of Theoretical Biology. The fact that this preprint is getting attention in the press probably says more about the author's self-promotion skills than about its quality. -- BenRG (talk) 05:34, 17 October 2011 (UTC)

Compare to http://motls.blogspot.com/2011/09/potential-mistakes-in-opera-research.html#clocks-thirty-nanoseconds Dualus (talk) 09:49, 17 October 2011 (UTC)

Well, Luboš is a real physicist, or was, but this objection sounds as stupid as it did before. The OPERA report says that the positions of the emitter and detector were measured with identical GPS receivers and the distance between them (straight-line, apparently) was calculated from those coordinates. It's impossible for the motion of the GPS satellites relative to the line between emitter and detector to be relevant, because they didn't do any correlation between the GPS signals at the endpoints. They just used the outputs of the GPS receivers. You might think the satellite motion would be relevant if you think that in relativity "everything is relative" and you have to consider things "from the perspective of" various moving objects involved in the problem, but that's not true. What relativity actually means is that you can pick any coordinate system you want as long as you're consistent. OPERA consistently used the ETRF2000 coordinate system.

For what it's worth, Luboš has said stupid things about experimental physics in the past: [8]. He's an expert on string theory, but he doesn't know much about data analysis. -- BenRG (talk) 16:38, 17 October 2011 (UTC)

Claims of 430 ppm CO₂ in 1940 atmosphere

Hi. I am referring to a graph (Beck, 2007 via Pettenkofer, Schulze, Spring, Krogh, Warburg, Lundegardh, Kreutz et al.) that purportedly shows measurements of atmospheric CO₂ using the "chemical method" where concentrations as graphed are >400 ppm pre-1830 and circa 1933–1945. It then shows a gradual near-linear increase starting in the early 1950s, identical to the Keeling Curve. Intuitively this does not make sense, but are there any reliable (and unbiased! - most of this data is from far-skeptical sources, ie. [9]) peer-reviewed journals or other scientific discussions on the chemical method? Thanks. ~AH1 ^(discuss!) 23:43, 16 October 2011 (UTC)

I suspect you refer to "180 years of atmospheric CO2 gas analysis by chemical methods", published in the very questionable Energy and Environment? There is a reply by Meijer and Keeling, of which I can only find free drafts online, not the published version. See Comment on" 180 years of atmospheric CO 2 gas analysis by chemical methods" by Ernst-Georg Beck'', Meijer, H.A.J. and Keeling, R.F., Energy & Environment 18(5):635-641, 2007. Basically, the problem with Beck is that early measurements were largely done in areas where CO2 levels swing widely and are dominated by local effects (like e.g. coal burning to heat cities, or places potentially downwind of fossil fuel using industries). So the problem is not in the actual measurement, but rather in the fact that the samples were not representative of the atmosphere at large. This view is reinforced because the large short-term swings claimed by Beck are implausible - there is no realistic source or sink for the huge flux required. --Stephan Schulz (talk) 15:01, 17 October 2011 (UTC)