Wikipedia:Reference desk/Archives/Science/2009 July 20

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July 20

Green things growing in water

One of the answers to the question above reminded me of something I heard on the radio whilst half-asleep this morning (it was the early morning fishing phone-in on TalkSport, if anyone is interested). According to the host, if you were to fill a pop bottle or a jar with ordinary tap water, seal the lid down tight, then leave it outside in a place that catches the sun - within a couple of weeks the vessel will be completely filled with algae and similar-looking slimy green stuff.

Supposing that this is true - how on earth does it work? --Kurt Shaped Box (talk) 00:58, 20 July 2009 (UTC)

Algae, Algal bloom, Seaweed, Phytoplankton, Bacterioplankton and Cyanobacteria may help. Basically you are creating an environment that promotes growth for plant/bacterial species without the animals that would keep them in check in the open water. 71.236.26.74 (talk) 02:26, 20 July 2009 (UTC)

Nuts. It's simply not true. You can't have any of those things without sources of carbon, nitrogen, sodium, and potassium, among other things, and none of those are present beyond trace amounts in tap water. Looie496 (talk) 02:31, 20 July 2009 (UTC)

I don't believe it. Where would it get nutrients? Tap water is pretty much a lost cause, so you're stuck with the soda residue?

People building Algae reactors put an awful lot of effort into making "green stuff" grow. Just putting some tap water in the sun is far too easy. APL (talk) 02:35, 20 July 2009 (UTC)

Yeah, that's what my high-school knowledge of algae was telling me. Guy also said that distilled or boiled water definitely doesn't work... --Kurt Shaped Box (talk) 02:37, 20 July 2009 (UTC)

Actually tap water isn't a lost cause - depending on where you live, there's likely to be enough micronutrients in your tap water to support algal growth. Again, depending on where your tap water, the nitrate content can be fairly high. There's also going to be CO₂ in the water - it's fairly soluble in water, and depending on your water source, the water may contain a significant amount of carbonate/bicarbonate derived from mineral sources (think lime scale).

It's also important to realise how little mass there is in a thin film of algae. Guettarda (talk) 06:15, 20 July 2009 (UTC)

Ok, I can believe that, but he said "completely filled with algae". APL (talk) 12:39, 20 July 2009 (UTC)

True. But "completely filled" is in the eye of the observer. I really should try it... Guettarda (talk) 13:07, 20 July 2009 (UTC)

It really depends on pot-luck what's in the water. There's this species of algae that form long threads a couple of those and the bottle may look to some as though it's "filled". I think Zygnematales may be what I'm thinking of. They can use hydrogencarbonate in water as well as CO2. If the show host's tap water supply is lake water that has undergone comparatively little filtering that might work. They would grow a whole lot better, though if he left the lid on only loosely. The fact that he wants the lid on tight makes me think that he might be trying to breed Cyanobacteria. Our article says there are freshwater species. Kurt and his show host are in the UK in Europe. The EC have a "directive on the quality of water intended for human consumption" ((98/83/EC) [1] and related documents. Based on those member states have issued lists of required mineral content and maximum levels for other stuff. European countries generally don't chlorinate their water as heavily as US utilities, unless they have to. So the experiment suggested may yield the observed results only in certain locations. If you use water from a pond rather than tap water it should work in most places. 71.236.26.74 (talk) 19:11, 20 July 2009 (UTC)

How much energy remains in the spent nuclear fuel produced yearly from US nuclear reactors?

Each year America's current 104 LWR reactors produce 2000 tons of spent nuclear fuel.

America's LWR only burn a tiny portion of the Uranium fuel in their fuel rods (about 3% or less) before the fuel rod is considered expended and is changed out.

What is the energy value left in 2000 tons of spent fuel rods after they have been removed from US LWRs, assuming complete burning of all fissile (U-235) and fertile (U-238) Uranium in an ideal breeder reactor that would extract all of the energy from the Uranium fuel?

source: IDB Reference Characteristics of LWR Nuclear Fuel Assemblies from the 1996 Integrated Database Report provides the following reference data about PWR and BWR fuel assemblies: http://www.nucleartourist.com/basics/hlwaste.htm —Preceding unsigned comment added by Friend2all (talk • contribs) 02:58, 20 July 2009 (UTC)

Prob'ly not much, at least in terms of usable energy. If all the uranium is burned up, what's left is just the fission products, and they (mostly) decay too quickly to be of much use for energy production. Besides, until the fission products decay, the spent fuel is lethally radioactive so there's no conceivable way to extract the energy from it. FWiW 76.21.37.87 (talk) 03:22, 20 July 2009 (UTC)

I must add that an "ideal breeder" is impossible to construct -- even the most advanced breeders will become poisoned by fission byproducts when their concentration in the fuel reaches 15-20% or so (during which time an equivalent amount of U-235 will be burned up, and maybe 20-25% of U-238 will be converted to fissile Pu-239), so this is obviously not a realistic scenario. (Although you could reprocess the fuel multiple times using advanced nuclear reprocessing methods to separate out the fission products and reuse the uranium and plutonium, which would give you more-or-less the same effect.) FWiW 76.21.37.87 (talk) 03:30, 20 July 2009 (UTC)

How much energy does a typical LWR reactor produce from a fuel rod in the current design and change-out schedule (i.e., what's the yield when 3% is used)? Assuming you could get up to the full 100% via the same decay processes (i.e., completely consume the partially-consumed isotopes using the same reactions), my hand-waving damn-all-practical-considerations answer is "an additional 97/3 times what 3% gives". DMacks (talk) 08:54, 20 July 2009 (UTC)

Sorry, I misunderstood the question. (Thought the OP asked how much energy remains in the fuel rods after 100% of the uranium's burned up.) 76.21.37.87 (talk) 06:23, 21 July 2009 (UTC)

It seems like lots of potentially useful fuel is to be expensively entombed for millenia over political objections of the state where the burial is to be. Breeder reactors could provide much more energy from the "spent" fuel. The problem is that bomb materials would be part of the fuel cycle and it is hard to tell "rogue" states not to emulate the present world powers if they built breeders. Edison (talk) 03:38, 21 July 2009 (UTC)

I agree, Edison, breeder reactors and reprocessing technology are the way to go (unfortunately, I don't have a whole lot of knowledge about these technologies, except for a little bit on the reprocessing end). As for your concern about proliferation, there's a pretty simple way to prevent that: Simply make a trade embargo on all breeder parts / materials / technologies, and strictly enforce it!!! That will put a stop to all those terrorist nations building breeders and making bomb material! It will require eternal vigilance of course, but it can be done. 76.21.37.87 (talk) 04:24, 21 July 2009 (UTC)

Everything needed to make a basic breeder reactor is already public knowledge. An embargo could slow things down, but any nation large enough to have the appropriate raw materials and industry could build one from scratch eventually. Dragons flight (talk) 04:54, 21 July 2009 (UTC)

Most terrorist (i.e islamic) nations don't have the industrial capacity to build a breeder from scratch at this time, so we should concentrate on making sure it stays this way. 76.21.37.87 (talk) 05:23, 21 July 2009 (UTC)

Besides, those people are too retarded to build a breeder reactor without Western (or Russian, or Chinese) nuclear experts doing all the design work. (All they're good at doing is blowing people up.) Keep the expertise out of the terrorist nations, and that will stop them from making the bomb. 76.21.37.87 (talk) 06:09, 21 July 2009 (UTC)

Can you tone down the anti-Arab/Muslim rhetoric a little? It's irrelevant, unhelpful, and offensive. -Elmer Clark (talk) 19:19, 21 July 2009 (UTC)

O ho, so now look who's sticking up for terrorists! For the record, Islamic nations are behind (almost) all the terrorism that's been happening in the past 30 years; they're sold on the idea of global jihad to force their ideology on others; there's widespread support for terrorism in most Islamic nations (in particular, in the Arab nations at least 60% or more of the total population supports terrorism, just look at the Gallup polls that's been conducted there); while at the same time the Islamic nations are the most oppressive totalitarian dictatorships in the world (just look at what's happening in Iran, for example)! And as for them being retarded, statistics show that the Arab world "produces virtually zero scientific papers and patents" (as shown by a 2002 UN report on the condition of the Arab world), which is proof enough that Islam rots your brain more than anything else. Must I add the Islamics' extreme mistreatment (to say the LEAST) of women, which is well-documented in many different sources and which is yet more evidence that they're nothing more than savages and barbarians?! 76.21.37.87 (talk) 00:24, 22 July 2009 (UTC)

Your vast oversimplification of very complicated subjects is the very definition of bigotry. It's also unrelated to the question. Please keep it civil and at least vaguely on topic. TastyCakes (talk) 02:43, 22 July 2009 (UTC)

What's so complicated about terrorism, I would like to know?! They've been fighting their jihad against the Western world since time immemorial, and we must fight back until we win the final victory, IT'S REALLY THAT SIMPLE. Besides, their so-called "culture" is responsible for more violence worldwide than any other culture (both toward other nations and toward their own people), while at the same time creating very little of anything worthwhile. I agree that this discussion is not directly related to the question, but I was giving my views on how to stop terrorist nations from acquiring nuclear weapons technology (which is COMPLETELY related to the original question), and it was Elmer Clark who brought up this discussion in the first place. And BTW, why would I "keep it civil" with regard to the savages who BRUTALLY MURDERED three THOUSAND of my countrymen/women on 9/11?! 76.21.37.87 (talk) 03:51, 22 July 2009 (UTC)

Regardless of whether there's any merit to what you're saying, there's no need to bring up your hatred for Arabs and Muslims practically every time you make a comment. Frankly you're coming off as a right-wing jingoist character account. -Elmer Clark (talk) 13:06, 22 July 2009 (UTC)

Ya, I'm starting to think this guy is just a troll. TastyCakes (talk) 14:14, 22 July 2009 (UTC)

For the record, I am a right-wing jingoistic American patriot who loves Western (and especially American) culture more than any other in the world, and who hates any and all nations that choose to be the enemies of my country. (A quote from Teddy Roosevelt seems to be in order: "A man who loves other countries as much as his own stands on a level with a man who loves other women as much as his own wife".) As for your accusation of trolling, I would strongly advise you to review my other contributions (from the archives, etc.) before making such a serious accusation -- remember, making false accusations can be viewed as slander. 98.234.126.251 (talk) 23:30, 22 July 2009 (UTC)

No, he's right. Every time I use an Algebraic Algorithm to determine the Azimuth of Algol, I have to think that even at the Zenith of its development, Arab culture has made no lasting contributions. That causes me to reach an emotional Nadir, but usually a glass of Alcohol helps me get out of it. --Stephan Schulz (talk) 16:59, 22 July 2009 (UTC)

FWiW, there's strong evidence that it was the Hindi people who first developed algebra, not the Arabs. And as for astronomy, I must (regrettably) acknowledge that the Arabs had in the past made some contributions to that science; however, it was European astronomers (Greek, then Roman, then Italian / German / Polish / etc.) who made the MOST lasting contributions to astronomy. That leaves alcohol, which almost everyone agrees is a mixed blessing. :-) 98.234.126.251 (talk) 23:38, 22 July 2009 (UTC)

You might wonder where that "regrettably" comes from and what it says about you. And whoever "first developed algebra" - by your own reasoning about astronomy, the lasting contributions are what counts. More to the point, only someone with an abysmal knowledge of history can honestly deny the massive contributions of the Islamic Golden Age to the development of human knowledge. --Stephan Schulz (talk) 00:08, 23 July 2009 (UTC)

I'm not denying that there were some contributions made by the Arabs, but I must reiterate that overall, their contributions to science and technology were minor compared to those of the West and the Far East. (Just compare how many discoveries / inventions were made by Arabs from 1200 BC to the present, vs. how many were made by all the Western civilizations from the ancient Minoans to today's Americans.) Furthermore, many discoveries / inventions that are traditionally attributed to the Arabs (such as algebra) have been developed by their neighbors (Hindis / Persians / Byzantines / Chinese / etc.) and stolen by the Arabs through warfare and plunder, and then subsequently introduced to the West via the Crusades. Whereas the vast majority of discoveries / inventions attributed to the West were actually made in the West (first in Greece, then in Rome, then in the Byzantine Empire, then in Western Europe beginning with the Renaissance), only a small proportion of those being "appropriated" from non-Western cultures. And also, may I point out to you that even for those discoveries / inventions that were beyond doubt GENUINELY, LEGITIMATELY made by Arabs, in almost all cases, those who made them were NOT believers in the Islamic religion, but had a more-or-less agnostic worldview? 98.234.126.251 (talk) 01:00, 23 July 2009 (UTC)

"Islamic nations are behind (almost) all the terrorism that's been happening in the past 30 years"? Really??? Tell that to the British and Irish, the Spanish, and the Sri Lankans. Or even the Germans, Japanese, the Peruvians, the Nicaraguans, or heck even the Turkish. And see what they think of you and your "right-wing jingoistic American patriot" ways... Even if your "right-wing jingoistic American patriot" outlook may make you miss this, there's actually a big wide world out there other then the US. (N.B. My understanding from the above, earlier conversations and IP lookups is 98 and 76 is the same person, if I am mistaken, forgive me) Nil Einne (talk) 14:45, 23 July 2009 (UTC)

Well if you are going to claim not to be a troll and stand by your silly statements I may as well respond to them more thoroughly. First to say that the Arabs haven't developed anything of any use in modern times is misleading. You could also make a very similar statement about the Chinese - they have been hopelessly behind the West technologically since the industrial revolution. But would you say that the Chinese are "retarded"? I doubt it. The problem wasn't with the people themselves it was with their leadership - their development was stifled by poor (and sometimes tragic) policies of the communists and the governments that preceded them. They failed to develop technologically advanced industries or develop quality places of learning as a result. To a degree I would argue the same is true for the Arabs. Their crappy (sometimes borderline criminal) governments have left them without the institutions that generated the surge of human knowledge the West has produced over the past few hundred years. Islam plays into this only as much as it impacts the government or what passes for it - in some cases (like Saudi Arabia) there is a huge level of impact while in others (like Turkey, not Arab I know but the closest example of a large, secular Muslim state) there is much less. Throughout my time in school and university I have met many very bright, ambitious Arabs, often second generation Canadians or Americans, and I don't think your statement as to their intellects is racist as much as it is just outright wrong.

As for your statement that Arabs largely support acts of violence against America, perhaps in part you're correct. But most of those that do don't do it for the reasons you suggest - they don't do it because they want Islam to be the only religion in the world or for religious reasons of any sort. They do it because the history of the region has developed a very deep "us against them" attitude with regards to the US, as much a secular dislike as anything else. The main roots of this dislike (I would say) are in the Israel-Palestine issue and the Iraq war. And as you have so kindly demonstrated, it goes both ways - many Americans such as yourself see Arabs as the enemy and are quite happy to see them attacked. But the rub is this - all of this is at a "nation state" level. On a personal level, I've met Arabs (in Egypt, Syria and Yemen, as well as in Canada and the States) who are some of the kindest, warmest people I know, to Americans or anyone else. No they're not huge fans of the American government - but what do you expect when there are tens of thousands of their kinsmen dying because of an invasion that, in hindsight, probably wasn't a very good idea? You hate Arabs because of what a handful of them did one day in 2001, killing thousands of people. How do you expect them to respond to hundreds of thousands of foreign troops in their land for years, or to defeat after humiliating defeat over Israel? You are quick to throw out your ugly words which were probably pretty close to every Westerner's thoughts at the end of 2001. But unlike many others, in the long time since you have failed to even consider the other side's point of view, or to how your "solutions" could ever last when they would leave so much more bitterness in the world. There are terrorist Arabs, it is true, and I make no apologies for them. But the vast majority of Arabs, the ones you say support terrorism, have about as much likelihood of actually acting on that as you do going to Iraq and killing some of them. TastyCakes (talk) 20:29, 23 July 2009 (UTC)

Hey, I didn't know that you have such a low opinion of the Chinese and their culture. Just so you know, the Chinese had actually developed quite a few useful things over the years (paper, rockets, gunpowder :-) etc.) -- not as much as the West, of course, but more than the Arabs. And for the record, I did NOT say that the Arabs NEVER developed anything useful -- to say this would be factually incorrect -- but rather, that their contributions were few compared to those of the West and the Far East, and that they were all made by non-Islamic, agnostic Arabs BEFORE Islam became the established, official religion in the Arab world. For the record, I've met with a few non-Islamic (either Christian or agnostic) Arabs, and I wouldn't say that they were less intelligent or more violent than the average person; it's the Mohammedians that are dumb, fanatical and violent. So it's not that their bloodline that's the problem: it's their stupid religion that rots their brains and makes them into the fanatical monsters that they are. As for their support of terrorism, IT DOESN'T MATTER WHAT EXCUSES THEY MIGHT MAKE FOR IT: THEY'RE SELF-ADMITTED ENEMIES OF AMERICA AND SUPPORTERS OF TERRORISM, SO THEY ALL BEAR THE BLAME FOR 9/11 AND THEY'RE ALL LEGITIMATE TARGETS! WHY WOULD "THE OTHER SIDE'S POINT OF VIEW" EVEN MATTER WHEN THOSE SAVAGES WERE DANCING IN THE STREETS WHILE THE TWIN TOWERS WERE BURNING -- AIN'T SUCH BEHAVIOR PROOF ENOUGH THAT THEY'RE EVIL SAVAGES AND ENEMIES OF ALL CIVILIZED NATIONS?! And as for the "Israel-Palestine issue", I'll remind you that it was the Arabs who first launched an UNPROVOKED attack on Israel, on the very next day after it was established! To say that the Arab / philistine cause in this conflict is legitimate is tantamount to claiming that Israel is an illegitimate nation-state that should not have been established, which is a clear admission of anti-semitism on your part, as well as a PERSONAL attack on my family in Israel! As for the Iraq war, I'll also remind you (in case you have total amnesia) that it began AFTER 9/11, and only a COMPLETE IDIOT would blame 9/11 on the Iraq war! And BTW, I'd think that the reason all those Arabs in Egypt / Syria / Yemen are "some of the kindest, warmest people" to you on a personal level is because you're a disloyal, self-hating, anti-American, anti-semitic, globalist "citizen of the world" who doesn't give a crap for America's freedom and prosperity, and would just love to see the US concede defeat in our Great War on Terror when we could easily win with all the firepower we got! Hell, if it wasn't for traitors like you calling for "moderation", we might have won the war already! 146.74.230.113 (talk) 00:34, 24 July 2009 (UTC)

As for you claiming that our noble efforts to exterminate the terrorists would "leave so much more bitterness in the world", this calls for a quote from Mark Antony: "Let them hate, so long as they fear." 146.74.230.113 (talk) 00:40, 24 July 2009 (UTC)

Ah well, I suppose I didn't expect a very different response from you. Good luck with the not being banned for inflammatory rhetoric. Please refrain from personal attacks, especially ones that don't make any sense like me being a "disloyal" citizen of a country I am not a citizen of. For the record, I usually fall on the Israeli side of the argument, but I think only a fool would see the conflict as a one sided affair. I also note that the "people dancing in the street" after 9/11 were indeed Palestinians, driven entirely by their opposition to Israel and its majour benefactor. The current anti-Americanism in the middle east (probably at its highest level in living memory, and to which I was referring) is due, in my view, almost entirely to the war in Iraq. I supported the war, and I continued to support it because it seemed the consequences of a premature pull out would be disastrous, and hugely irresponsible on America's part. If anything I thought many more troops should be sent, to quell the uprisings and sectarian tensions once and for all. But I think it is safe to say if we knew everything we know now, it should not have been started in the first place. You also chose to ignore the critical word of my point regarding China: modern history, handily defined as "since the industrial revolution". You also have your history out of order, they call it the Islamic Golden Age because it happened after the founding of Islam. TastyCakes (talk) 06:31, 24 July 2009 (UTC)

And as for the extermination of terrorists, and having them fear America, I'm all for it. But your definition of terrorist would seem to be impractically wide, to the point where you are essentially advocating genocide. At some point you have to draw some lines, you have to make a lasting peace. Defining every Muslim in the world an enemy would make the "War on Terror" an impossible venture. TastyCakes (talk) 06:37, 24 July 2009 (UTC)

OK, since you've made it clear whose side are you on, I take back the "anti-American" part. However, you're still COMPLETELY WRONG AND OUT OF BOUNDS to blame America for the anti-Americanism in the Middle East, since the level of hatred for America in that region had been at more than 60% LONG BEFORE THE IRAQ WAR OR EVEN THE 9/11 ATTACKS, so you have to be either totally ignorant or have a completely distorted view of the conflict to claim that the Iraq war was a significant factor in that. As for "making a lasting peace": THOSE PEOPLE WILL ALWAYS HATE US AS THEY ALWAYS HAVE, AND NOTHING WE DO WILL CHANGE THAT, SO THE ONLY WAY TO ENSURE THAT THEY WON'T ATTACK US IS TO MAKE THEM FEAR US EVEN MORE THAN THEY HATE US. That's my point: make them fear American firepower, and they won't ever mess with us again for fear of what's gonna happen to them if they do. 98.234.126.251 (talk) 07:38, 24 July 2009 (UTC)

I would say the national fallacy of the US (not shared by all, but by too many) is the assumption that there are only two kinds of people, good and evil, that the good ones all share the American Dream, and that you only need to deal with the evil ones to make the world into a perfect place. Surprisingly, though, when you bomb a village containing maybe 2 "terrorists", killing 3 families and half of a fourth of harmless farmers, only a few of the remaining people in the village will understandingly talk about unavoidable collateral damage of the war on terror and thank the pilot. --Stephan Schulz (talk) 07:15, 24 July 2009 (UTC)

And if they be "harmless farmers", then WHAT THE HELL ARE THEY DOING SHELTERING TWO TERRORISTS IN THEIR VILLAGE?! WHY DON'T THEY KICK THOSE TWO CHARACTERS OUT?! Remember, IF YOU KNOWINGLY SHELTER A TERRORIST IN YOUR HOME (VILLAGE, WHATEVER), THEN YOU'RE JUST AS GUILTY AS THE TERRORIST AND YOU BECOME A LEGITIMATE TARGET YOURSELF! Besides, as I already said, WINNING THE WAR ON TERROR IS NOT ABOUT GETTING THEM TO LIKE US (WHICH THEY NEVER WILL), BUT ABOUT MAKING THEM FEAR US. 98.234.126.251 (talk) 07:44, 24 July 2009 (UTC)

Well, first off, the "terrorists" may not be terrorists, or the villagers may not know that they are terrorists, or they may be forced to shelter them, or they may not consider them terrorists. Given that the US is sheltering any number of people others can rightfully call "terrorists", does that excuse 9/11? If not, why not? And why does the same argument not apply to some village in Afghanistan? --Stephan Schulz (talk) 14:17, 24 July 2009 (UTC)

TLRBreak1

C'mon, 98.234 -- what YOU call a terrorist, that farmer might call brother-in-law. Or in some well-documented cases, terrorists terrorise local villages, too, demanding or helping themselves to food, shelter, women and possibly children to train as soldiers. If that helplessness escalates to being killed by American bombs, they will NOT love American for "liberating" them, they will HATE America for killing people who knew themselves to be innocent victims themselves.

You can't make ideological terrorists FEAR you; to them it is just a challenge. You CAN make innocent civilians HATE YOU, which is liklier to make them support those who are against America. They will NEVER see their losses as a fair exchange for getting rid of the "terrorists" among them, as for various reasons they have precious little choice about the presence of those people.

And if you believe collateral damage, and/or bombing whole countries back to the dark ages is okay, because the end justifies the means, you are so morally wrong you give up your right to pass judgement on others. If you believe the solution is to "make the fear us" then that is a belief you SHARE with the "terrorists".

Even on purely pragmatic grounds, if you'd look at the history of "terrorist" movements through the ages, you'd see every civilian death, every reprisal-looking action, only increases the numbers and ferocity of the "terrorists". - KoolerStill (talk) 13:21, 24 July 2009 (UTC)

So what you're saying, America is a "terrorist nation" for bombing Germany and Japan during World War 2?! If so, then you (KoolerStill) are a nazi and you give up your right to pass judgment on me and on my fellow Americans! And BTW, when two-thirds of a nation's population hate your guts and want all of your people dead, then indiscriminate total warfare against that nation's entire population IS a justifiable option on purely moral grounds (once again, e.g. Germany and Japan). (Besides, your accusation that I'm a terrorist counts as a personal attack, and I DEMAND that you take it back just like I took back my own personal attack against TastyCakes.) And if the villagers knowingly shelter terrorists no matter what their reason, then they're just as guilty as the terrorists and just as legitimate a target. And if they don't know that there are terrorists among them, well we just have to LET THEM KNOW; maybe we could drop a bunch of leaflets that say something like, "You have N number of terrorists sheltering in your village, their names are such-and-such, here's their pictures, turn them in to us by such-and-such a deadline (say 48 hours) or we will destroy your village". And then you betcha the villagers will turn them in, not because they don't like the terrorists, but simply out of fear of what will happen to them all if they let'em stay. (BTW, we're already seeing this start to happen in some parts of the Islamic world, e.g Lebanon, parts of Iraq, etc.) As for your accusations that the US is sheltering "terrorists" (i.e. contras), you're dead wrong -- the contras are not "terrorists", but freedom fighters fighting AGAINST Cuban-sponsored communist terrorists who were trying to take over all of Latin America. They're no more "terrorists" than the French Resistance, or the Russian partisans in World War 2. And even if we were sheltering / aiding terrorists in the proper sense of the word (which we might have done in the past), this would still not be a moral equivalent to the Afghans aiding terrorists, because, as you're well aware, the US is a democratic nation with an advanced, civilized culture that believes in personal freedom, is responsible for a large part of the scientific / technological / cultural / economic progress worldwide, and treats women more-or-less decently, while the Afghans (in particular) are savage barbarians who choose an oppressive theocracy over a free democracy, torture and kill their women just for going outside without permission, and have contributed NOTHING worthwhile to the world's civilization! And if you still insist on calling America a "terrorist nation" (or even saying that America's War on Terror is morally equivalent to the terrorists' jihad against America), then you are an anti-American terrorist and traitor yourself!!! 98.234.126.251 (talk) 23:34, 24 July 2009 (UTC)

So what you are saying is "we're better because we're better and therefore we are allowed to use whatever means we think useful" - well, apart from the fact that the so-called War on Terror is not particularly useful (except for the terrorists), yours is one of the morally most corrupt arguments I've ever heard. No you (or we) are not better a-priori. We (should) hold the moral high ground because of how we act. It does not give as an excuse to behave like assholes and bullies. But I appreciate how you stand up for the core American values of free speech and free discourse in the public place. What land exactly would I be a traitor of? --Stephan Schulz (talk) 07:48, 25 July 2009 (UTC)

Even if what you're saying is not treason in the legal sense, it's still despicable because you're sticking up for terrorists and KNOWINGLY undermining our will to fight them to the finish! And what makes you think that our culture of freedom and democracy is no better a-priori than their culture of oppression and violence -- especially seeing how they're trying to force their barbaric way of life upon everyone else (just like the German and Japanese fascists before them), while we are trying to DEFEND our own way of life and that of other free nations against those filthy savages?! And BTW, where did you get that stupid notion that the War on Terror "is not useful except to the terrorists", and WHY ARE YOU MISREPRESENTING THIS PIECE OF HOGWASH AS AN ESTABLISHED "FACT"?! And besides, didn't we use "whatever means we thought useful" (including the carpet bombing of entire cities) in World War 2, and if so, weren't we fully justified in doing that?! I'd very much like to know whether you're just sick in the head, or whether the oil sheikhs are paying you to spread their propaganda for them?! 98.234.126.251 (talk) 08:28, 25 July 2009 (UTC)

I see. So you know what's right (because God told you?), and everybody who disagrees is a despicable traitor. I'm glad that Jefferson, one of my personal favorites among the founding fathers, got rid of most of the Alien and Sedition Acts. Comparing the current "War on Terror" with WW2 is a historical shenanigan. WW2 was a symmetric war, with real risks for at least some of the allies on each side. The few Islamic terrorists are no significant thread to the West or to the US, unless we support them by dismantling our systems of civil liberties ("and justice for all"). 9/11 was bad, but its only a 20% increase in the one year murder rate of the US. By comparison, about 45000 people a year die in traffic accidents in the US. Terror in the West is a negligible threat to individuals, and no existential threat to the states. As for WW2, I think the large-scale carpet bombing was an unfortunate mistake from a humanistic, but in particular from a strategic point of view. More focussed attacks would have had a stronger military effect with fewer civilian victims, and fewer overall victims on both sides. But hindsight is 20/20, so I don't blame the actors at the time. They were in a real struggle against a real threat, and mistakes happen. We are not under a significant threat, and have no such excuse. As for the Sheiks paying me: Sure, that's why I keep arguing for a decreased use of fossil fuels all the time. --Stephan Schulz (talk) 11:12, 25 July 2009 (UTC)

So YOU think that "we" are not under a significant threat, well 9/11 just by itself proves that you're dead wrong -- those terrorist bastards proved that they could easily kill 3000 people all at once, and will do so if given half a chance in hell. And what if they get their filthy hands on chemical weapons (as they're trying to do) and release a bunch of mustard gas (or even nerve gas) in the New York subway, do you KNOW how many TENS OF THOUSANDS of Americans would get killed?! I wonder if you'll still talk about terrorism in the same dismissive way that you do now if THAT kind of attack happens. As for "dismantling our systems of civil liberties": well, that's the VERY reason why we're fighting the War on Terror abroad, so that we won't have to dismantle our civil liberties at home in order to prevent the next massive attack (possibly with poison gas next time, or something of that sort). (BTW, "justice for all" means "justice for all who live in America", not "justice for the rest of the world".) Why do you think we haven't been attacked here in America for these past almost 8 years? Well I'll tell you why: because the terrorists are too busy trying to save their filthy asses over in Afghanistan to have time to prepare the next attack here in America. For the record, the War on Terror has already killed most all of Al-Qaida's top generals, so for the time being all they can do is make uncoordinated localized attacks on our soldiers and kill a few at a time at the most -- and as long as we continue pounding them over there, they won't have the time or the resources to come over here and kill hundreds of our people. It's a basic principle of strategy: keep attacking the enemy whenever you can, and the enemy won't have time or resources to regroup launch a major attack. If you don't know that, I recommend you read up on Clausewitz before you go discussing strategy with anyone anywhere. 98.234.126.251 (talk) 00:19, 26 July 2009 (UTC)

Ugh - it was so obvious that this guy was trolling for an excuse to start up this "debate." I just had to say something. Anyway, I recommend everyone take all this with a grain of salt - for my money, this guy's way too perfect of a right-wing blowhard to really be one. Let's stop wasting time feeding him. -Elmer Clark (talk) 07:35, 26 July 2009 (UTC)

Yeah, point taken. But I had my reply ready, complete with a quote from Jefferson, when I ran into an edit conflict. So one more time:

Re. 98: Right. I do a little magic dance around the campfire every night. I've not been eaten by lions since I started doing that, so magic works. Why again, has the US not been subject to serious Islamic terror for the 200 years before 9/11? Justice just for Americans? Well, on the one hand tell that to José Padilla. But on the other hand, that's an utterly despicable position, and one that Jefferson would spit on. "We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness." - and that was written before the founding of the US. --Stephan Schulz (talk) 07:52, 26 July 2009 (UTC)

Elmer Clark -- you're so wrong about your characterization of me when you imply that I'm not a real right-winger but just a troll. For the record (as I already said before), I am a far-right ideologue (or "blowhard" as you put it) who sincerely believes (and with good reason) that America is the best nation in the world and should always act in its own best interest and not in the interest of other nations. And for the record, I wasn't trolling, just bluntly stating my position on how to prevent terrorist (i.e. Islamic) nations from acquiring nuclear weapons technology. And I meant every word that I said, except for those parts that I have later stricken from the thread. As for Stephan Schulz's last statement, it's a classic example of fallacious logic and demagoguery. The comparison between the "War on Terror -- no major attacks" and "magic dance -- not eaten by lions" is the clearest example of a false analogy that I've ever seen, just think for yourself! And why has the US not been subject to Islamic terror before 9/11 (or, rather, before the Iran hostage crisis) -- well, that's because they couldn't carry out a major terrorist attack against the US, because they didn't have the capability to do that which they do now! And regarding Jefferson, may I remind you that despite saying that "all men are created equal", he owned numerous slaves, so either he meant that "all men [belonging to a certain subset] are created equal" (as I interpret this statement), or he didn't practice what he preached. (BTW, I personally prefer to think the former explanation is true -- I'd much rather think of Jefferson as an Anglo-Saxon chauvinist than as a hypocrite.) 98.234.126.251 (talk) 22:39, 26 July 2009 (UTC)

I'm fairly certain Jefferson was both - he thought Negros generally inferior, still believed they should be free on principle, but did not act on this belief. Read e.g. Notes on the State of Virginia. He was still a great thinker and a visionary. You, on the other hand, are both hypocritical and a chauvinist, but neither a great thinker nor a visionary. You also don't have the excuse of being born in the 18th century. --Stephan Schulz (talk) 23:12, 26 July 2009 (UTC)

"You, on the other hand, are both hypocritical and a chauvinist..." -- Chauvinist, yes; hypocritical, WHAT MAKES YOU THINK THAT?! 98.234.126.251 (talk) 23:59, 26 July 2009 (UTC)

And besides, how do you know if I'm not a visionary in my own field? How do you know if I wasn't working just the other day on some great invention in the field of oil refining or coal liquefaction that could change the world and get the US off of foreign oil imports? You don't; you can't. 98.234.126.251 (talk) 00:05, 27 July 2009 (UTC)

I think everybody can judge your level of hypocrisy from your postings so far. If you don't see it, too bad for you. That would reflect on your lack of vision (sorry for the pun). Yes, the argument that "I'm anonymous (or secretive), so I could be a great thinker" is really a strong one. "Put up or shut up" seems to be an adequate answer to that. --Stephan Schulz (talk) 00:20, 27 July 2009 (UTC)

Calorie/Kilocalorie

Hello, I am asking this question as I am confused over it. I noticed several sites mention the daily calorie requirement for an adult male in calories, for example someone needs 2400 calories per day. Is it correct? I mean will it be calorie or kilocalorie (i.e. 2400 Kcal)? For example a Cucumber has a food value of 20 kcal, then taking only one cucmber means taking 20,000 calories which is far more than daily calorie requirement. --AquaticMonkey (talk) 03:16, 20 July 2009 (UTC)

No-one uses the original calorie when talking about nutrition. Calorie always means the same as kilocalorie. Algebraist 03:18, 20 July 2009 (UTC)

See Calorie#Kilogram and gram calories for a discussion of this. The article says “in the context of food energy the term calorie generally refers to the kilogram calorie”, but I think that’s a severe understatement. I don’t think I’ve ever seen “calorie” mean “gram calorie” in a food context. Red Act (talk) 03:41, 20 July 2009 (UTC)

You also should know that daily intake to maintain an adult's wt varies enormously. 2400 may be average, but some people need half that and some twice that. alteripse (talk) 16:22, 20 July 2009 (UTC)

For example, if you're performing hard physical labor (working in a furniture warehouse, etc.), you can easily require 5000+ calories a day. 76.21.37.87 (talk) 04:27, 21 July 2009 (UTC)

Little greedy bastard

I have just been savaged by one mosquito. I have a simple question. Why did the little bugger, per their typical MO, feed on me four or five times in just a few minutes, rather than just once? I scanned our article on them it does not explain this feeding habit.--Fuhghettaboutit (talk) 04:24, 20 July 2009 (UTC)

Because you're delicious. --jpgordon^{::==( o )} 06:02, 20 July 2009 (UTC)

Are you positive it was the same mosquito?CalamusFortis 06:33, 20 July 2009 (UTC)

My guess is that it probably has something to do with the size of the blood meal. Either your skin is hard to get through, your blood clots too quickly, or you're chasing the poor mosquito away before she's finished feeding. All she wants is enough protein to produce a batch of eggs. Guettarda (talk) 13:13, 20 July 2009 (UTC)

I am quite delicious, and I Guettarda makes a good point about my androcentric selfishness, but after some thoughtful self-examination, I find I still hope she choked.--Fuhghettaboutit (talk) 22:09, 20 July 2009 (UTC)

There was a TV commercial for Tabasco sauce (or some similar product) where guy was eating a bunch of it, mosquito bit him, and moments later the critter burst into a little fireball. DMacks (talk) 00:48, 21 July 2009 (UTC)

I read once that mosquitoes go for overweight men more than any other demographic. Read into this what you will. Vranak (talk) 01:30, 21 July 2009 (UTC)

My guess would be simply that the mosquito knows it only has a limited time before you notice it biting you. It takes a short while between being bitten to when the swelling and itching starts, the mosquito doesn't want to be around when that happens or there is a much greater chance you'll swat it. It makes even more sense if the mosquito's prey is not humam. Vespine (talk) 04:13, 21 July 2009 (UTC)

You may be tightening your skin when you notice them. They notice the tightening and fly away because they expect you to swat them. Try to keep your skin relaxed if you're going to try to swat. 70.90.174.101 (talk) 06:03, 22 July 2009 (UTC)

Or just be really quick at swatting the "moskeeter". 98.234.126.251 (talk) 23:40, 22 July 2009 (UTC)

I remember my uncle showing me a trick with mosquitos once. After seeing a mosquito and on his arm he began flexing his arm very rapidly, but at the same time staying still so as not to frighten it away. After a few seconds the mosquito began to swell, and burst. After seeing this, I have grossed out several friends, girlfriends, family members, etc. by using the same trick. What I've never figured out, is why she just sits there when she knows shes overfull of blood.Drew Smith What I've done 06:21, 25 July 2009 (UTC)

I think that by flexing your arm, you're setting up pressure waves in your blood vessels that force your blood into the moskeeter very rapidly until it bursts from internal pressure. FWiW 98.234.126.251 (talk) 08:36, 25 July 2009 (UTC)

Beetles nesting in old disks

While going through storage to throw things out I came across a number of old SyQuest 44mb removable hard disks that probably haven't seen the light of day in almost 10 years. Inside each one I found a sizable number of beetle larva (probably A. unicolor), both live and shed casings. Is this a common occurance? Is there something in the disks that makes them attractive? Horselover Frost (talk) 05:26, 20 July 2009 (UTC)

Dust? --Dr Dima (talk) 07:35, 20 July 2009 (UTC)

Did those disks have Beatles songs recorded on them? Maybe that's why those beetles found them disks to be so attractive. ;-) 76.21.37.87 (talk) 04:30, 21 July 2009 (UTC)

Fusion of vertebrae with age - painful?

I understand that as people age, more vertebrae of the lower spine fuse together. When two vertebrae fuse, is this painless and unnoticed by the subject? 78.146.249.124 (talk) 11:04, 20 July 2009 (UTC)

Remember that Wikipedia does not give out medical advice, but you might find information at Spinal fusion, which describes the deliberate fusion of vertebrae as "to relieve pain" not cause ir. SGGH ^ping! 11:17, 20 July 2009 (UTC)

I'm not quite sure what medical advice is being sought here, seems like a straightforward enquiry about a condition. Let's assume good faith. Ankylosing spondylitis is a condition where fusion of the vertebrae occurs. The article contains information you may find helpful. Richard Avery (talk) 15:14, 20 July 2009 (UTC)

Fusion of the vertebrae in the Sacrum is a part of normal development, see [2]. It is not painful, and is unnoticed by the subject. As far as I know, fusion of the lumbar, or of other vertebrae, does not occur in a healthy subject. --NorwegianBlue ^talk 19:15, 20 July 2009 (UTC)

The original poster may be referring to bone spurs that commonly form on vertebrae as people age. They don't typically "fuse" vertebrae together, but spurs from one vertebra may touch spurs from an adjacent one, and they may impinge on nearby spinal nerves which certainly can cause pain or paresthesia. - Draeco (talk) 03:53, 21 July 2009 (UTC)

Capillarity

I was reading a book in soil science, expressing the capillarity in tubes. It is suggesting that the pressure in the raised water inside the tube in negative, which I don't feel well that. I'd like to know more about capillarity specially from molecular point of view. Could anyone give some help and sources? Re444 (talk) 11:30, 20 July 2009 (UTC)

Xylem and Capillary action Surface tension would be a start.71.236.26.74 (talk) 03:56, 21 July 2009 (UTC)

Temperature X-Treme

From Extremes on Earth, the hottest measured air temperature was 58°C, measured in the Sahara desert. This got me thinking - on a hot day, ground or object temperatures (eg inside a car, or at the surface of an asphalt road) may be higher than the air temperature. Is this true, or is this an illusion based on the way humans perceive temperature? If it's true, I can build a contraption (I was thinking of a box made of metal painted black, and one side covered by a glass sheet, facing the sun) which would become hotter than the air temperature. Is there a theoretical limit to how hot I can make something by heating it with solar radiation alone, and about how hot would that be? — QuantumEleven 12:08, 20 July 2009 (UTC)

Yes, that is true. In theory (and unless I'm mistaken) you can make something as hot as the emitting surface of the Sun - about 6000 K, although that is technically implausible for more reasons than I can think of ;-). See Solar thermal energy. Solar box cookers reach cooking temperature without explicit concentration of solar light, large solar installation use mirrors to reach much higher temperatures. --Stephan Schulz (talk) 12:22, 20 July 2009 (UTC)

Why would the surface of the Sun be the limit? Tempshill (talk) 17:14, 20 July 2009 (UTC)

The short answer is the second law of thermodynamics. Heat does not flow (without assistance) from a cooler to a hotter body. The long answer causes me headaches ;-) --Stephan Schulz (talk) 21:06, 20 July 2009 (UTC)

Again, heat!=temperature. In theory, you could concentrate the received thermal energy into smaller and smaller masses, increasing the temperature drastically higher than 6000K. See the "solar furnace" comment below. -RunningOnBrains^{(talk page)} 21:47, 20 July 2009 (UTC)

Our solar furnace article says that temperatures of 3000 ^oC have been achieved by concentrating sunlight. Gandalf61 (talk) 12:42, 20 July 2009 (UTC)

A classical thermal solar collector consists of a thin box with the bottom painted black and a glass top, tilted to face toward the equator. You run cool water in at teh top and get warm water out at the bottom. This works because the glass lets light in but does not let infrared out very well. -Arch dude (talk) 20:43, 20 July 2009 (UTC)

If you put two objects - one hot and the other cold - into an enclosed, perfectly insulated environment, they'll eventually equalize in temperature - right? If one of those objects is the sun and the other is your box - then they'd eventually become equal in temperature...if they were insulated from the environment. However, in any practical setup, your box can radiate heat off into space - heat can be conducted away by the air, etc. But if you were to perfectly insulate your box from the rest of the universe and let it heat up - it would eventually match the temperature of the sun. This happens on the sun-facing side of spacecraft - which have to be rotated to allow parts to face away from the sun and cool off. Apollo 8 span at a rate of one rotation per hour which resulted in a spacecraft that was at +200C on one side and -100C on the other! Our Solar cooker article suggests that it's fairly easy to get temperatures up to 150C with relatively simple home-made equipment. SteveBaker (talk) 01:59, 21 July 2009 (UTC)

No; equilibrium means no net energy transfer, *not* equal temperature. If you placed the sun and a box into a perfectly insulated environment (no energy loss) with no convection/conduction and all radiation exchanged (impossible in practice), the blackbody radiation energy transfer can be estimated by the equation $W=\sigma \cdot A\cdot T^{4}$, where A is the surface area of the object and T is the temperature. For all but ridiculously large boxes, A_box will be significantly smaller than A_sun. Thus for equilibrium T_box will necessarily be greater than T_sun. With numbers: A_sun = 6.0877×10¹⁸ m², A_box = 6 m², T_sun = 5,778 K, T_box = 1.83*10⁸ K (interesting perhaps, but useless since one of the premises is faulty). Of course, practicality insists that no such perfectly reflective and insulating environment exists, the equations above are rather simplified, and (thankfully) much of the solar radiation is lost to space. – 74  04:33, 21 July 2009 (UTC) (edited 74  06:09, 22 July 2009 (UTC))

"with no convection/conduction" is an important limitation not explicitly mentioned prior to 74.137.108.115's comment here. If the only energy transfer is by radiation, then equilibrium is when the rate of loss and gain is the same, and it makes sense that loss of a black-body object would depend upon temp and surface area. However, if there's actual thermal contact (convection or conduction) I can't see a way to escape the "heat flows from warmer to cooler" basic law of thermodynamics. I don't think you can have a "one-way insulator", except you can get some similar effect if you control the rate of radiation separately from the rate of conduction/convection (as described in the solar-oven box). DMacks (talk) 07:07, 21 July 2009 (UTC)

No, convection/conduction is irrelevant - I was assuming the pure radiation case. Please not that both bodies, the sun and the box, are absorbing and radiating, and both processes are proportional to the surface area. Assuming both are black bodies, they will reach equilibrium at equal temperatures. Otherwise I could build a perpetuum mobile: Put a large and a small sphere into an isolated box, wait until the small one is warmer, open the box, use the heat difference, close the box... --Stephan Schulz (talk) 07:33, 21 July 2009 (UTC)

Eh, it works as far as the overly simplified equations are concerned. The devil is in the details, of course. Specifically, the assumption that all the radiation is exchanged. It appears I have reinvented a perpetual motion machine: the Energy Sucker. So sorry, no free lunch here. – 74  06:09, 22 July 2009 (UTC)

Limit is dependent on energy received by the Earth from the Sun. Sun's surface temperature is 6000K, but Corona is much hotter at one to three million Kelvin. By theory at least, Sun's surface temperate should not be limit. Practically archived temperature in solar furnace is 5430K, suggesting that 6000K may indeed be the limit. - manya (talk) 04:46, 21 July 2009 (UTC)

There is no fundamental reason (but there are sure practical ones) temperatures above 6000K should not be achievable by using concentrated sun light as described by gandalf. (even if we forget about the Corona for argument sake and simplicity). Arguments based on thermodynamic equilibrium neglect the fact that there is no equilibrium in the situation described. Dauto (talk) 05:46, 22 July 2009 (UTC)

Influenza A epidemic

Does it make any sense trying to brake the epidemic? At least in the Northern Hemisphere, where is summer now, wouldn't it be a better approach to let it spread, before the winter, and treat the sick?--Quest09 (talk) 16:19, 20 July 2009 (UTC)

Are you referring to the H1N1 pandemic? I do not know of an Influenza A epidemic, and did not see anything about it on the CDC website, so I suppose that it is possible that there is such an epidemic outside of the US. If you are in fact talking about the H1N1 pandemic, most medical treatment is minor, identical as far as I can tell to treatment for normal flu types. Only a small percentage of those who become infected require hospitalization. Googlemeister (talk) 16:37, 20 July 2009 (UTC)

H1N1 is a subtype of influenza A virus, as is described in our article 2009 flu pandemic. --NorwegianBlue ^talk 16:53, 20 July 2009 (UTC)

There is no way to break the pandemic. It is unlikely that we have any way to even reduce the spread at this point. The expected vaccine is still months away and the virus is too widespread for isolation-based control measures. Luckily, the virus is not much worse than ordinary flu, so far. Rmhermen (talk) 17:19, 20 July 2009 (UTC)

That's exactly the point. The government can't brake the pandemic, however, some governments keep trying to isolate people. Wouldn't it be easier to just let it run and concentrate on treating the ill? Quest09 (talk) 18:09, 20 July 2009 (UTC)

Even well intentioned well informed government officials are likely to take irrational measures when it comes to infectious diseases just to feel (or make the public feel) that they are doing something about it. Dauto (talk) 21:25, 20 July 2009 (UTC)

PS. same reasoning applies to the stupid security we nowadays have to go through every time we travel by plane. Dauto (talk) 21:27, 20 July 2009 (UTC)

You can blame that on the filthy terrorists who crash planes into buildings, or blow them up. I agree that (by analogy) it would be better to concentrate the security on stopping potential terrorists rather than checking everyone; however, all those evil Arab organizations and crooked "civil liberties" groups aren't letting us implement a meaningful profiling system... 76.21.37.87 (talk) 04:38, 21 July 2009 (UTC)

I don't have a problem with security. My beef, as I pointed out earlier, is with stupid security. Profiling is a member of the latter. Dauto (talk) 05:28, 22 July 2009 (UTC)

I think this is difficult to answer. While you can't break the pandemic, it doesn't mean you can't slow the spread. Whether the current measures some governments have implemented have slowed the spread is IMHO difficult to answer but I would say it's definitely possible. Slowing the spread has several advantages. 1) It avoids overloading the health system (particularly important for countries in the southern hemisphere, yes I know the OP referred to the northern hemisphere) 2) You buy time for a vaccine 3) It avoids panic 4) It will hopefully reduce the negative effect of the outbreak on the economy (many areas including tourism). Nil Einne (talk) 09:25, 21 July 2009 (UTC)

Breast implant's rejection

Why don't breast implants get rejected by the body? Quest09 (talk) 18:14, 20 July 2009 (UTC)

Because they're composed of inert silicone or saline and plastics. Transplant rejection is a function of the body's immune system attacking the biological material of the transplanted organ. Similarly, implanted metal (plates, screws, what have you) is not subject to rejection. — Lomn 18:24, 20 July 2009 (UTC)

All that stuff eventually gets encapsulated with 'stuff' (yeah, I know - my knowledge is epic), which can cause problems in its own right though, can't it? --Kurt Shaped Box (talk) 21:47, 20 July 2009 (UTC)

Scar tissue does form around the implant, which can harden to cause capsular contracture.[3] Red Act (talk) 00:27, 21 July 2009 (UTC)

Explain about Prion Diseases

I know what a prion is, but I can't find a completely understandable explanation of why prions start duplicating. Could someone please give me an understandable explanation why? Dogposter (talk) 18:20, 20 July 2009 (UTC)

For inherited prionic diseases, see PRNP and PRNP#Disease linkage. Quoting from Prion

To date, all [prions] that have been discovered propagate by transmitting a mis-folded protein state; the protein does not itself self-replicate and the process is dependent on the presence of the polypeptide in the host organism.

Intelligentsium 18:49, 20 July 2009 (UTC)

Okay, thanks! Dogposter (talk) 18:54, 20 July 2009 (UTC)

Prions are autocatalytic. That is, the presense of a prion in the cellular interior stimulates the formation of additional prions from the precursor unfolde proteins that would otherwise form the normally-folded form of the molecule. -Arch dude (talk) 20:33, 20 July 2009 (UTC)

That sounds really scary! Is there any way that the immune system can deal with all them prions? Also, is there any treatment that's effective against them? 76.21.37.87 (talk) 04:41, 21 July 2009 (UTC)

No, prion diseases are currently untreatable and universally fatal, though it may take many years for symptoms to develop in some cases. Dragons flight (talk) 04:46, 21 July 2009 (UTC)

Mein Gott! 76.21.37.87 (talk) 05:25, 21 July 2009 (UTC)

May be that phrase "Although CJD is the most common human prion disease, it is still rare, occurring in about one out of every one million people every year" taken from the Creutzfeld-Jakob disease article will offer you some confort... Dauto (talk) 17:10, 21 July 2009 (UTC)

Good, now if we can just keep it that way... 76.21.37.87 (talk) 00:31, 22 July 2009 (UTC)

So basically your body thinks that since a prion is there, it must be correct? Dogposter (talk) 13:50, 21 July 2009 (UTC)

That's one way to look at this. Or, you can picture a prion's action in the body as the prion binding to some protein and twisting it another prion like itself, which then goes on to twist another protein into a prion, and so on... (that's the way I think of this). FWiW 76.21.37.87 (talk) 00:30, 22 July 2009 (UTC)

Rabies vaccine

Why is the rabies vaccine not given routinely, as are the DPT vaccine, Varicella vaccine, etc.? I understand it is extremely unlikely that any one person will contract rabies, but upon contracting rabies, it is very unlikely that the person will survive without prior or immediate vaccination, and many rabies victims are unaware that they have been infected until it is too late. Is it not better to err on the side of caution? Intelligentsium 19:08, 20 July 2009 (UTC)

I do not know if it is applicable to the rabies vaccine, but most vaccines have a very small probability of giving the disease. Even if that rate is 1 in 1,000,000 it would probably cause more rabies deaths then it would prevent. It is also not free to make or distribute the vaccine. Googlemeister (talk) 19:22, 20 July 2009 (UTC)

There are many possible reasons, but I expect the most significant are directly related to just how unlikely rabies is. The cost of vaccinating a population is quite high, in terms of dollars, resources, and possible consequences of side effects. The US sees approximately two cases of rabies in humans per year. By contrast, there are approximately four million births in the US annually. A "one in a million" chance of complications from a vaccine would double the number of incidents, and do so in a segment of the population most susceptible to illness (the young). Additionally, our article on the vaccine notes that, even vaccinated, humans require treatment after a bite. Put together, world health authorities have concluded that this is an ineffective way to combat rabies. Rather, the US, Canada, Europe, and others are primarily combating rabies via oral vaccines of carrier populations, which seems to be more effective at far less cost. — Lomn 19:24, 20 July 2009 (UTC)

(EC) Speculation: except for tetanus, the diseases you listed are contagious, which rabies isn't really (not enough people biting people to support an outbreak). Vaccination policy's cost-benefit analysis probably has more to do with preventing epidemics than protecting individuals from rare diseases. --Sean 19:27, 20 July 2009 (UTC)

My wife received the vaccine, and experienced side effects that were not dangerous, but were unpleasant (pain and soreness). So combine that with the reasons others have given, and it's kind of a hard sell if you're not in a high-risk group. -- Coneslayer (talk) 19:35, 20 July 2009 (UTC)

In my understanding, routine vaccinations are highly effective for contagious diseases (smallpox, measles, polio, diphtheria, etc.) because they not only protect the person being vaccinated, but also the others, by reducing the incidence of the disease. Rabies disease, however, have a huge animal carrier pool, but is extremely seldom transmitted between humans; so vaccinating a person only protects that particular person. Vaccinating the animals that may infect each-other as well as humans makes more sense, and is indeed carried out routinely in some countries. AFAIR there is a bait (oral) vaccine for foxes and jackals available, but there well may be other types, too. --Dr Dima (talk) 20:02, 20 July 2009 (UTC)

Right, that's the catch. You vaccinate the domestic dogs and cats, not the humans. That probably takes care of 90% of potential cases; humans aren't bitten by wild animals all that often in the Western world. (I got stung by a bee last year, I think that was as close as I've come in a long time!) --98.217.14.211 (talk) 23:02, 20 July 2009 (UTC)

I don't know if this is still the case but the vaccine used to be delivered by injection into the stomach muscles - a very painful procedure - this would decrease it's uptake as well. Exxolon (talk) 01:41, 21 July 2009 (UTC)

I think that it was the rabies *treatment* that they used to inject into the abdominal muscles. Several times over several days. --Kurt Shaped Box (talk) 02:28, 21 July 2009 (UTC)

As I understand it, the vaccine is the treatment. The incubation period of rabies is long enough that the patient has time to build up a protective immune response before the virus causes symptoms. Though I wouldn't be surprised if a more aggressive vaccination is used for patients who are believed to have been exposed, than for those who are simply at risk to be exposed at some later time. --Trovatore (talk) 03:10, 21 July 2009 (UTC)

Earth's Net Charge

I learned in my physics class that Earth has a net negative charge to the tune of about 500,000 C. I found this interesting since we were also discussing how you can generate a charge by friction (ie. combing your hair) and the idea occurred to me that maybe the negative charge came from the hypothetical collision between the Earth and Theia, creating the moon. So basically my question is, has the net charge of the Moon ever been measured? If not, is it possible to? Would be kind of cool if it turned out to be net positive. And also if I'm overlooking a really obvious reason for the Earth's net negative charge, please let me know. Thanks in advance. Ginogrz (talk) 22:48, 20 July 2009 (UTC)

I think you’re misunderstanding the 500kC charge. The conducting layers of the ionosphere and the earth’s surface essentially form a capacitor, that’s charged by about 500kC.[4] That’s presumably just due to atmospheric effects. But that doesn’t mean that the planet as a whole, including the ionosphere, has a net charge. I would think that a planetary net charge like that would be extremely difficult to determine, since we have no way of measuring charge density below the earth’s crust. Red Act (talk) 00:56, 21 July 2009 (UTC)

Google tells me that Earth has a net charge of near zero because the solid earth has a charge of -500,000 C and the atmosphere has a charge of about 500,000C. As to your charge about the moon I don't know but in it's doubtfully very large- most things in such as planets aren't so charged I thought. In general strong nuclear force holds together atoms(i.e holds together the protons in the nucleus where the electric repulsion trumps the gravitational attraction by many orders of magnitude), electric force holds together things on a microscopic scale (compare the relative strengths of the electric field and gravitational field between two electrons) and on a macroscopic scale (i.e the universe) its gravity that holds things together because the net electric charge on objects is so much less then the mass of the objects. Most objects aren't like an electron with a charge that is appreciable as compared to the mass. Computeridiot34 (talk) 01:00, 21 July 2009 (UTC)

It looks like whether the earth has a net electric charge is a matter of scientific debate. See this and this. Red Act (talk) 01:14, 21 July 2009 (UTC)

The question of the earth’s net electric charge was discussed on this reference desk a few months ago.[5] Red Act (talk) 01:18, 21 July 2009 (UTC)

Yeah, I most certainly was misunderstanding it. The capacitor scenario certainly makes a lot more sense than a massive body having a significant net charge, as Computeridiot34 pointed out. Some interesting reads as well, I didn't know it was such a debated topic, but such is science. Thanks. Ginogrz (talk) 01:58, 21 July 2009 (UTC)

North and Suth America

Is there any evidence N and S America is currntly moving north? this site is tough to folow along. To what direction is Antartica plate moving. The slide shows, the ice (in white) will melt green in about 50 million years.--69.228.145.50 (talk) 22:56, 20 July 2009 (UTC)

plate motions. Dragons flight (talk) 01:16, 21 July 2009 (UTC)

No - to the contrary. A westerly or south-westerly trend seems more likely. Our article North American Plate says "For the most part, the North American Plate moves in roughly a southwest direction away from the Mid-Atlantic Ridge." but South American Plate is not so helpful. It kinda suggests a westerly motion since the ocean floor is spreading to the east of the continent - and it's being subducted to the west. The Antarctic Plate article says that it's moving in the direction of the Atlantic ocean...which is in a northerly direction...but then ANY motion of the antarctic plate could be described as "northerly"! SteveBaker (talk) 01:40, 21 July 2009 (UTC)