Wikipedia:Reference desk/Archives/Science/2011 October 18

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October 18

Wiping out humanity

How to wipe out world's human population? --Jigsaqqq (talk) 00:05, 18 October 2011 (UTC)

Nuclear warfare is a good way. →Στc. 00:14, 18 October 2011 (UTC)

doomsday event and Doomsday device covers a lot of them. Vespine (talk) 00:33, 18 October 2011 (UTC)

Human extinction too. Clarityfiend (talk) 01:45, 18 October 2011 (UTC)

Nukes can be evaded by hiding in deep caves, at the cost of developing Eloi/Morlock dichotomy. A genetically tailored attack via a transmissible pathogen would get the job done more assuredly. Mad scientists are presently trying to recreate the specific pathogen of the "black death", which killed about 1/3 of humans in the 14th century. Other mad scientists might wish to create a pathogen which would affirmatively exterminate the species, while asserting that "all research will be done in highly secure facilities." (D'oh!) Edison (talk) 01:46, 18 October 2011 (UTC)

Send a spacraft to Ceres, change its orbit so that it will collide with Earth. The effects of the impact will be similar to the effects of the largest impacts of the Late Heavy Bombardment. Count Iblis (talk) 03:36, 18 October 2011 (UTC)

Whether against the Daleks or the Borg, resistence is fultile. But the question should be how to wipeout mankind. If the question is how to wipeout humanity, Islamism, Nazism and Communism among many other isms, will all suffice without any cause external to man.μηδείς (talk) 03:46, 18 October 2011 (UTC)

This will be an irrelevant question after next Friday HiLo48 (talk) 03:45, 18 October 2011 (UTC)

At least this time he had the decency to wait for the World Series to conclude. However, since the Cubs aren't in it, it's unlikely the world will end on that day. ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:31, 18 October 2011 (UTC)

Good catch, but the beings involved will have moved on to other realms, not ceased to exist. μηδείς (talk) 04:04, 18 October 2011 (UTC)

... or only "an hundred and forty and four thousand" of them, according to some interpretations (not mine). Dbfirs 06:33, 18 October 2011 (UTC)

Fittingly, that number is a thousand time gross. ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:31, 18 October 2011 (UTC)

The most certain way would be to wash away the atmosphere. No more air, no more humans. ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:33, 18 October 2011 (UTC)

Some suggestions: 1 2 3 4 5 6 --Dweller (talk) 11:37, 18 October 2011 (UTC)

Convince everyone to stop having babies. Mitch Ames (talk) 11:58, 18 October 2011 (UTC)

Probably a runaway greenhouse effect leading to methane hydrate gasification. Depending on how much we can open up geologic resources before the end, we might even outdo the previous effort and end up with something like Venus. Wnt (talk) 16:18, 18 October 2011 (UTC)

Or triggering a Snowball earth period by painting the Earth's continents white. I think this can actually be implemented without much effort, there is enough white paint or white colored materials available to cover the continents with. Count Iblis (talk) 17:35, 18 October 2011 (UTC)

Diseases, too. As long as it spreads quickly enough before vaccines come out humans can be killed out easily. 174.93.67.107 (talk) 20:53, 18 October 2011 (UTC)

Obviously just wait. Humanity will be wiped out sooner or later. :P ~AH1 ^(discuss!) 02:16, 19 October 2011 (UTC)

Dude, you've been asking these questions for a while now. Have you acquired a secret volcano base yet? You may also want to start hiring minions. -- Obsidi♠n Soul 07:56, 21 October 2011 (UTC)

Certifying obtained knowledge

If someone learned something about science through many of the available sources online (Khan Academy, Open Lecture, and even wikipedia), how could he certify it? Without enrolling in a paid university course on the same topic, obviously. 2.138.252.233 (talk) 00:44, 18 October 2011 (UTC)

Some educational institutions offer what is known as Recognition of prior learning or Recognition of current competency. These tend to apply in the technical further education sector, and not the higher education sector. The higher education sector has traditionally prided itself on its right to certify. Fifelfoo (talk) 01:06, 18 October 2011 (UTC)

Duck vs. Goose

After reading duck, goose and the associated family and genus articles, I can't seem to determine the rationale behind a bird being labelled as one vs. the other, other than perhaps the data that most ducks display sexual dimorphism and most geese mate for life -- that's can't be it, though, because how would the exceptions avoid being classified as the other bird? So what makes a duck a duck vs. it being a goose? Is it size? DRosenbach ^{(Talk | Contribs)} 01:10, 18 October 2011 (UTC)

Just flipping through some of the various bird field guides on my shelf, I'd say overall body size + relative neck length are the obvious differences. AFAIK, there are no long necked "ducks". But I have no references for you, sorry. The Masked Booby (talk) 01:36, 18 October 2011 (UTC)

AFAIK = As Far As I Know? Plasmic Physics (talk) 01:52, 18 October 2011 (UTC)

对。The Masked Booby (talk) 02:31, 18 October 2011 (UTC)

In modern biology, the only accepted reason for grouping things together is common ancestry. Traditional groupings, though (of which duck and goose are examples) only indicate that things looked similar to somebody at some time. Based on a quick reading, the "true geese" (anserini) are a proper monophyletic grouping, and other genera that are referred to as geese are closely related. However, the category of ducks is highly paraphyletic, in other words, not a good grouping by the standards of modern biology. Looie496 (talk) 01:58, 18 October 2011 (UTC)

Jue = Yes? Plasmic Physics (talk) 03:44, 18 October 2011 (UTC)

Only polyphyletic groups, like pachyderms are considered inherently invalid due to uncommon ancestry in all taxonomic systems. Groups like the reptiles or fish can still be described usefully as grades, since they do all come from a single common ancestor. If one describes swans as big-bodied geese and geese as long-necked ducks then all three groups are valid grades in the same sense as apes or monkeys. μηδείς (talk) 04:02, 18 October 2011 (UTC)

Quite simple. If it LOOKS like a duck, and WALKS like a duck, then it is one. Otoh, if it looks and walks like a goose, then it is the latter. (This shows how absurd the original maxim is). Myles325a (talk) 07:05, 18 October 2011 (UTC)

That's pretty close to the truth of it. If it's a member of the Anatidae and it looks like a duck, then it's a duck. The method of distinction between frogs and toads isn't really much different either. --Kurt Shaped Box (talk) 18:22, 18 October 2011 (UTC)

The answer is relatively simple: we don't classify organisms by common names in binomial nomenclature. "Duck" and "geese" while apparently a very important distinction to laypeople, are all arbitrary terms that has no bearing at all on scientific classification. Common names are usually based purely on the appearance of the species and does not reflect actual taxonomic ancestry, though in most cases, they do. And what's more, taxa are often not easily delineated, they are fluid as reflected by evolution and can include transitional forms that are hard to classify.

In scientific classification, a "good" taxon is one which reflects actual ancestry (think of it as a branch in the tree of life), while an "artificial" taxon is one which does not (i.e. the "branch" incorrectly includes the tips and leaves from other branches). Traditional taxonomy (especially Linnaean taxonomy) used morphology for classification resulting in a lot of "artificial" taxa grouped together simply because they looked alike. For example, all worm-like organisms were once grouped under the taxon Vermes by Linnaeus, including the chordate (and putative vertebrate) hagfish. This is obviously incorrect.

This has been superseded nowadays by a combination of morphology and genetics (evolutionary taxonomy). It gives a more accurate evaluation of the ancestry of an organism and can sometimes reveal surprising relationships that go against traditional classifications. The most striking perhaps is the discovery that birds are the descendants of theropod dinosaurs.

I do not know the details of phylogenetic studies that have been done on anatids but if it is classified by specialists to belong to the genus Anser, you can be pretty confident in calling it geese however it may look. By extension, closely related members of the tribe Anserini can also be called geese. Swans are also easy as they all belong to only one genus, Cygnus. Both swans and geese belong to the same subfamily - Anserinae.

Duck, however, is the usual common name for the rest of the family Anatidae, and as mentioned, they are not monophyletic (i.e. descended from a single ancestor). But "duck" is also more specifically used to refer to the dabbling duck subfamily Anatinae (whose interrelationships are still unclear), especially members of the genus Anas (which probably did not descend from a common ancestor). There is still work being done on resolving taxonomical relationships within the ducks.

In between them is the subfamily Tadorninae, shelducks and shelgeese considered an intermediate taxon between dabbling ducks and members of Anserinae. Tadornines show morphological traits common to both anatines and anserines.

You can compare this to human classification. Humans belong to the the family Hominidae, the "great ape family". While humans are obviously commonly called humans, members of the family are collectively commonly known as "great apes" or hominids and it includes chimpanzees, gorillas, and orangutans (genera Pan, Gorilla, and Pongo respectively). Of which Humans, human ancestors, and chimpanzees belong to the same subfamily (Homininae) and the same tribe, Hominini, the hominins. Baboons on the other hand, while superficially similar to apes and are still sometimes called apes by laypeople are actually monkeys belonging to the family Cercopithecidae and only distantly related to true apes (members of the superfamily Hominoidea, which includes gibbons in addition to hominids).

And as Kurt Shaped Box mentioned, frogs and toads are distinguished in the same way - by how they look. But "true frogs" are members of only one family - Ranidae, and "true toads" to another - Bufonidae. Even then there are members of Ranidae for example that are called toads in their common names simply because they look more like toads than frogs.

The bottom line is that what people commonly call an organism does not really matter in terms of classification or ancestry. -- Obsidi♠n Soul 03:01, 19 October 2011 (UTC)

Their relative size and throats can matter in the sense that ducks quack and geese honk. Ducks can be throaty sounding at times, but not as deep, long and as loud as the geese I've heard. --Modocc (talk) 05:14, 19 October 2011 (UTC)

I think that the logical conclusion here is that a duck is a bird that if it isn't a duck, might very well be mistaken for one... AndyTheGrump (talk) 05:21, 19 October 2011 (UTC)

Electrothermal-chemical technology

I don't completely understand what this is, maybe someone can help me. Is it basically just changing the way the gun ignites the propellant? Does it use liquid propellant? ScienceApe (talk) 03:26, 18 October 2011 (UTC)

Guess I'm not the only one who doesn't know what this is. ScienceApe (talk) 15:03, 19 October 2011 (UTC)

I'm not sure, but I think it uses an electrical spark to ignite the powder, instead of the usual firing pin / blasting cap combo. Please correct me if I'm wrong. 67.169.177.176 (talk) 05:59, 21 October 2011 (UTC)

That would just be electronic firing, this is supposed to be more sophisticated. ScienceApe (talk) 01:51, 22 October 2011 (UTC)

question (coloured bats)

Bats are generally found in shades of dark black colours. Now-a- days orange coloured bats are also seen . What is the reason for this colour change? — Preceding unsigned comment added by 117.211.18.135 (talk) 04:47, 18 October 2011 (UTC)

You mean like these? — Michael J 05:42, 18 October 2011 (UTC)

Or like this [1]. μηδείς (talk) 18:37, 18 October 2011 (UTC)

Maybe the OP means this "rare megabat". Where have you seen this orange bat?--Shantavira|^{feed me} 06:17, 18 October 2011 (UTC)

Or this one. I would suggest that these bats have existed for a long time and have only recently been noticed by you. Richard Avery (talk) 07:12, 18 October 2011 (UTC)

Bats did not "change" colors, they've always been that way. Flying foxes are very familiar to me as a lot of them are quite common here (the Philippines) roosting in tall fan palms and I can assure you they didn't "change". You just didn't know about them before as they probably don't exist in your area. Nonetheless, even common vesper bats like pipistrelles have colors ranging from black to dark brown to light yellow. You just don't encounter them that often as humans are diurnal creatures.

Also one common misconception of bats is that they all come out only during deep night which is actually untrue. Most bats are crepuscular (that is, they come out at twilight - dawn and evening), in such lights, the advantages of having a darker dorsal surface and a lighter lower surface is still significant enough that coloration matters. It protects them from aerial predators from above (owls, hawks, eagles, etc.) when seen against the terrain and disguises them from prey and predators alike on the surface when seen against the lighter colored sky. In addition, the more brightly colored bats actually come out very early in the evening and later in the dawn when there is still/already quite a lot of light, particularly fruit eating megabats (flying foxes and allies) which almost all rely on sight and smell rather than echolocation for finding food (with the exception of one species). -- Obsidi♠n Soul 04:03, 19 October 2011 (UTC)

Although not orange, the rarest, most beautiful and colorful of all bats is currently an undocumented bat that was nevertheless discovered by my elderly friend some forty-years ago here in the North Carolina foothills. He found four bats in all, one dead adult and three smaller young bats of which only one was still alive. They had been clinging to a sycamore branch that had been knocked down by a storm. Their wings were black, but their fur had yellows, greens and purple (one or more of these were possibly iridescent, and I need to speak with him again about this, because my memory of what he said exactly is fuzzy), which he compared to the colors of a peach or a parrot. Now my friend has repeated his full account on a number of occasions and he has a very keen eye and is observant (he assures me that their coloration was not due to the presence of other organisms such as algae), and says their furs were absolutely beautiful in color. Now I used to figure it was just a rare bat he had found, but then I learned it was undocumented, and now I understand it would be an incredible new discovery if its ever confirmed because mammalian fur is not known to ever have those colors. Thus the next time I visit my friend (which I hope will be soon), I will have him draw these bats and I will post his drawing here (with his permission of course). Note that the more common brown bats are frequently found sheltered in old barns, attics and caves, but this bat obviously roosts on the branches of trees reducing the chance of its discovery, especially if it is rare. However, bat species do generally have unique radar and call signatures, so researchers might be able to locate this elusive bat with the proper equipment, if it has not gone extinct already (there has been a lot of subdivision development going on in this area for the past forty years). --Modocc (talk) 21:09, 18 October 2011 (UTC)

By all means, do follow it up, but without a collected specimen, it's really all unreliable at this point.-- Obsidi♠n Soul 04:03, 19 October 2011 (UTC)

There is a fairly good chance that these bats are doing fine and will be found again. --Modocc (talk) 09:15, 19 October 2011 (UTC)

Even if you don't see the bats, please collect any carcasses, fur, or anything else that looks like it might have DNA in it. One DNA sample can prove the existence and perhaps the phylogeny of a species even if you don't know what it is. Wnt (talk) 20:21, 19 October 2011 (UTC)

I would, but my friend buried their remains and placed the surviving bat onto a limb. Some fifty years ago his property was near the edge of the undeveloped countryside here (he remembers when these local roads were unpaved), but the property is now in the middle of town and was sold and developed. At this point, systematic bat surveys further away in the less developed areas are needed in order to locate this bat now. --Modocc (talk) 22:10, 19 October 2011 (UTC)

Quantum "locked" levitation

Is this video real? If so, what keeps the relative position and orientation of the superconductor constant? Dualus (talk) 07:08, 18 October 2011 (UTC)

See Meissner effect. I did the same thing just the other day. It's not difficult, just labourious and, except for demonstration purposes, completely pointless. Plasmic Physics (talk) 07:57, 18 October 2011 (UTC)

Annoyingly, my superconductor kept spinning. Plasmic Physics (talk) 08:03, 18 October 2011 (UTC)

See also flux pinning. Red Act (talk) 08:13, 18 October 2011 (UTC)

My mistake, I didn't watch the clip to completion. Plasmic Physics (talk) 10:38, 18 October 2011 (UTC)

Completely pointless? I don't think so. I can think of a couple of good uses for it. Make it a couple hundred if room temperature superconductors are ever created. Dauto (talk) 12:54, 18 October 2011 (UTC)

That would depend on what planet your rooms is. Plasmic Physics (talk) 13:11, 18 October 2011 (UTC)

What's curious about this demonstration is that the object is "locked" in that it won't fall off from gravity, centrifugal force etc., but it is quite free to move when manipulated by hand. There must be some threshold above which force moves it, and below which force is resisted. How sharp is that threshold? Wnt (talk) 17:03, 18 October 2011 (UTC)

Also, how is he touching that? Isn't it really, really cold?? - Akamad (talk) 21:29, 18 October 2011 (UTC)

This would be an interesting mode of propulsion for magnetic trains or hovercraft. ~AH1 ^(discuss!) 02:10, 19 October 2011 (UTC)

I don't remember the name of the effect, but what's happening is that the solidified gasses on the superconductor are flash-evaporating, creating an insulating layer of gas between the experimenter's fingers and the superconductor. --Carnildo (talk) 22:36, 21 October 2011 (UTC)

vandalistic cockatoos and Tabasco Sauce

Wikipedia’s article on capsaicin, the active component of chilli peppers, informs us that birds do not have tongue receptors for this chemical, and so can happily munch on the fruit that makes mammals howl for relief. Apparently, the plants want birds to have a monopoly on its produce, because their eating behaviour and shorter intestinal tracts are less likely to destroy the seeds, and because they disperse the seeds more widely than mammals do.

So I was puzzled to read in the Sydney Morning Herald "Cocky show for a beaked vandal", September 7, (and in earlier articles) that Potts Point (in Sydney) residents whose patios and roofs are being torn apart by the beaks of sulphur-crested cockatoos are advised to dope wooden panels with Tabasco Sauce (an expensive concentration of chilli extracts). If Wikipedia is right, this is only giving the cockatoo a side dish in addition to their woody diet.

See http://www.smh.com.au/entertainment/tv-and-radio/wild-boys-bums-kept-mum-20110906-1juz9.html

and about a third of the page down is article: COCKY SHOW FOR BEAKED VANDALS

Anyone throw any light on this? Myles325a (talk) 07:17, 18 October 2011 (UTC)

Cockatoo spp distribution

This is something that has puzzled me for a while too. There are many chilli plants and many species of birds in my area. The birds happily eat pretty much anything that is available and yet I've never seen a bird of any kind eat a chilli. The only things eating chillis in my area are humans. To be fair, Chili_pepper#Evolutionary_advantages does say "Chili peppers are eaten by birds living in the chili peppers' natural range." Sean.hoyland - talk 07:42, 18 October 2011 (UTC)

Agree. Perhaps it is because the genus Capsicum is native to the Americas and cockatoos aren't? While there are plenty of introduced plants containing capsaicin in Sydney, chilies don't "know" they should be be palatable to cockatoos? Perhaps not all birds lack receptors for it? --Shirt58 (talk) 07:53, 18 October 2011 (UTC)

(Dons cork hat.) "Vandalistic cockatoos and Tabasco Sauce"? That's a bit bloody fancy, isn't it! Nothing wrong with just serving it with the traditional gravy and three veg, way it's always been done. And for the sake of you bloody mob of "masterchef" drongos, here's a recipe I picked up from an old swaggie in the Back of Bourke in me days as a jackeroo at Speewah station. Pluck the cockatoo, put it and a stone in a pot full of water, boil until the stone is soft, then eat the stone. Strewth!58 (talk) 08:12, 18 October 2011 (UTC)

That's an oldie but a goodie, Shirt. Btw, is Speewah station situated in any of the 4 states and 1 territory in which you simultaneously live? (Bilocation, that's nothing! Quinqualocation is what we have here. Neat trick.) -- Jack of Oz ^{[your turn]} 09:43, 18 October 2011 (UTC)

The RSPB advises adding chilli powder or (according to other sources, flakes) to food intended for wild birds in order to deter squirrels from stealing it. [2] [3], however in true balanced style other sources say [4] that some squirrels like (or at least don't mind) the taste Seems that just like humans, some squirrels like a phall while others prefer a korma. The RSPB advice does appear to indicate that UK bird species don't taste chilli, though. Tonywalton ^Talk 11:15, 18 October 2011 (UTC)

Both [5] and [6] suggest a number of parrots enjoy chillis. Evidentally one particular Moluccan cockatoo likes tabasco sauce [7]. This doesn't tell us that the sulphur-crested cockatoos like chillis or tabasco sauce and Psittaciformes is a fairly diverse order but even so it would seem odd to me that some parrots have no problems with capsaicin and other I'm guessing more distantly related birds likewise, but the sulphur-crested cockatoo does have problems. It may be there is something else in tabasco sauce that puts the cockatoo off of course. KSB could perhaps provide more general info on parrots and chillis. But to be blunt, the source you provide is what I would call 'not even close to reliable' for the claim. It mentions the suggestion of one random person. A quick search shows there doesn't seem to be any other mention of this random person outside repeats of that claim. So who the heck are they and why should we trust that they have any idea on how to ward off sulphur-crested cockatoos? They don't even say it works for them. I doubt the media in Australia is that different from here in NZ or for that matter what I've seen in the UK and US, so particularly in that context it's hardly surprising if they repeat nonsense suggestions made by random people, particularly when they make the government look bad/dumb/wasteful, without checking with someone to see if the idea made any sense. Nil Einne (talk) 11:14, 18 October 2011 (UTC)

The M2 is closely related enough to the SC2 to interbreed, if that means anything - and here's a video of a Moluccan eating a chilli, with no apparent distress. It should be noted that it is very typical for a parrot to take three or four bites of something and then drop the rest - doesn't indicate that it dislikes that particular food, only that it's lost interest for the time being. --Kurt Shaped Box (talk) 18:08, 18 October 2011 (UTC)

What Vespine sometimes wakes up to

I live near the Dandenong Ranges in victoria and I have this very problem, i built a bird feeder for the parrots, we get awesome king parrots, rosellas and Rainbow Lorikeet but the Sulphur-crested Cockatoo have been destroying my back porch, they've even started picking apart the actual DECK timbers! I also heard that chillis don't affect birds so I've bought a nerf type gun that shoots small paper darts to try to deter them. I've also considered a sprinkler type arrangement but that will squirt birds indeterminately which i don't necessarily want to do. I'll try the chilli and and report back, but it might take me a couple of weeks to get a result.. Vespine (talk) 22:06, 18 October 2011 (UTC)

Don't be surprised if your deterrents fail utterly, only work for a short while before the cockatoos disregard them, or actively become a source of amusement for them. You're dealing with very clever, very inquisitive animals here - think somewhat along the lines of chimpanzees in terms of intelligence. --Kurt Shaped Box (talk) 22:20, 18 October 2011 (UTC)

Some birds can apparently taste capsaicin, but instead of shying away like mammals do, they actually prefer it. Capsaicin-treated bird feeders actually show an increase in avian visitors. Adding tabasco sauce to wood paneling is like adding seasoning, so do be careful not to apply it liberally in your experiment or you might end up with a badly chewed up house, heh. You can try using grape juice, the Kool-Aid kind. They contain methyl anthranilate and dimethyl anthranilate, artificial grape flavoring which apparently deters some bird species though this has been not been replicated in the results of a study published in 2011. It's also stinky. :P -- Obsidi♠n Soul 01:44, 19 October 2011 (UTC)

Op myles325a back live. Thanks to all for some excellent research. And especially to Shirt58|Strewth!58. This appears to be something of an unsolved scientific problem.

It has been shown here that birds in general are impervious to peppers, and even like them. (If they have very few taste buds, then the hotness of the peppers might actually be a treat).

But it has not been demonstrated that the sulphur-crested cockatoo is impervious to peppers as well. (Though most agree that it would be very odd if they alone could sense the chemical.)

It has also been noted that, with newspapers, if anyone says that you can dope wood with Tabasco Sauce as a bird deterrent, then they will pick it up, repeat it, and soon you will have a meme that has no real credibility at all. The "Tabasco solution" was recommended by a person who was fighting against a proposed cockatoo cull, and so may have been a red herring-pepper (sorry). Myles325a (talk) 03:41, 19 October 2011 (UTC)

sql queries

find the average price of each type of the table movie whose attributes are type and price... — Preceding unsigned comment added by 42.109.10.45 (talk) 10:01, 18 October 2011 (UTC)

a) we don't have enough info to provide the answer and b) we don't do your homework, 'cos that way you'd not learn anything. --Tagishsimon (talk) 10:21, 18 October 2011 (UTC)

What? Banana slipper monkey. Can someone please translate into legible english. Plasmic Physics (talk) 10:25, 18 October 2011 (UTC)

My take on it is that they have a homework question for their database management class using SQL. The question involves trying to query a database but we don't have the table and they don't provide enough info for us to give them a solid answer. Dismas|^(talk) 10:32, 18 October 2011 (UTC)

c) Even if a) and b) didn't apply, which they do, this would be more appropriately asked on the Computing Reference Desk (but I wouldn't bother, as you'd more than likely get the same answer to a) and b) there) Tonywalton ^Talk 10:30, 18 October 2011 (UTC)

(EC) Well, in truth, we can imagine a table called MOVIE, which has attributes of, for instance, Movie_Name, Type, and Price, where Type is presumably a foreign key to a table of types. The OP wants to know the average price for movies of each type. So she/he will want to select all movies of each Type, and calculate the average Price of each. So I lied; we probably do have enough info to provide a query, but we're still not going to do so. --Tagishsimon (talk) 10:31, 18 October 2011 (UTC)

You might find that checking out groupby and avg to be of use. --Tagishsimon (talk) 10:35, 18 October 2011 (UTC)

select "type", average(price) from movie group by "type"; (no guarantee or warranty)←Baseball Bugs ^{What's up, Doc?} carrots→ 11:24, 18 October 2011 (UTC)

Fusion, Fission, and Iron

Why is it that fusion of atomic nuclei will release energy up until iron, after which fusion consumes energy (and fission releases it). What is the source of this energy (in both cases)? Also, does iron release energy with fission? --Goodbye Galaxy (talk) 16:44, 18 October 2011 (UTC)

Nuclear binding energy is your relevant article on the energy source and why the left part (up to iron) of the curve of binding energy concerns fusion and the right part concerns fission. --Mr.98 (talk) 16:54, 18 October 2011 (UTC)

I think in layman's terms, anything after iron requires you to put energy into the fusion reaction in order to fuse past iron. The source of energy comes from the strong nuclear force. ScienceApe (talk) 19:26, 18 October 2011 (UTC)

In red supergiant stars, fusion continues until iron and nickel, at which point a supernova occurs–this explosion creates heavier elements, including uranium. ~AH1 ^(discuss!) 02:05, 19 October 2011 (UTC)

Just as electron pairing determines valency and the fact that electron shells are full in noble gasses, making them unreactive, protons and neutrons in the nucleus pair up, and Fe has the most stable configuration of these pairings. This: The Elements: Their Origin, Abundance, and Distribution is one of the most fascinating, informative, and well-written books I have ever read, and my interests are biology and linguistics, not chemistry or physics. μηδείς (talk) 16:41, 19 October 2011 (UTC)

Urine albumin valid ranges

What is the absolute minimum and maximum values that a urine-albumin test can have? All I can find is the ranges for microalbuminuria, which I'm sure is not the total valid range. -- kainaw™ 18:58, 18 October 2011 (UTC)

~550-750 mg/L, third row from the bottom

Human serum albumin#Measurement says "36 - 52 g/L. (upper limit increased from 47 g/L on the 15th June 2007)" but the ridiculously busy File:Blood values sorted by mass and molar concentration.png says about 550-750 mg/L. So please request PMID 9049439 on WP:RX and correct and/or request corrections (e.g., from the graphics illustration labs here or on commons.) 67.6.179.27 (talk) 13:41, 19 October 2011 (UTC)

Requested. Dualus (talk) 13:50, 19 October 2011 (UTC)

Thanks, but serum-albumin is a much different measurement than urine-albumin. I've been researching this heavily and I've found that the lower limit is zero and there is no standard upper limit. -- kainaw™ 16:06, 19 October 2011 (UTC)

Agreed. Someone should still update the serum article. Canadian medical students can win a scholarship. Dualus (talk) 19:21, 19 October 2011 (UTC)

Electric energy from highly intensive neutron radiation?

Is it possible to transform highly intensive neutron radiation into electrical energy in a sustainable manner?, ie avoiding material fatigue. Electron9 (talk) 19:17, 18 October 2011 (UTC)

One way that was discussed a lot in the mid-1970s was to use a strong neutron source (like a fusion reactor) to break down water into hydrogen gas, and then carbonate the hydrogen to produce methane. (If you actually having working fusion reactors, you can also just use the neutrons to enrich a lithium blanket and produce tritium.) --Mr.98 (talk) 19:37, 18 October 2011 (UTC)

No, and it is proliferative. You can not control which atoms will undergo nuclear transmutation, so the heat is worthless. It can be used to make nuclear weapons. Dualus (talk) 23:09, 18 October 2011 (UTC)

I find your statements here to be very odd. Why would the heat be worthless? Any heat source that is large and reliable can be made into electric energy through a heat exchanger. That is not the hard part, assuming it is economical (a big if). Separately, it would take huge number of neutrons to be useful for nuclear weapons — comparable with an industrial sized nuclear reactor. Which is a lot of neutrons. (The US looked into the possibility of making a GIANT particle accelerator in the 1950s as a way of economizing on their uranium for reactors—code-named the Materials Testing Accelerator—but in the end found that there was a lot more uranium in the Southwest than they had expected there to be, and abandoned the project. I bring this up just to point out the difficulty of producing a neutron source of sufficient size to be a major proliferation threat.) Anyway, please feel free to clarify...

A separate, but related way to make energy from neutrons is to use the neutrons to turn thorium into U-233, and then use that in a reactor. But again, you'd need a huge neutron source for that to be useful. --Mr.98 (talk) 00:45, 19 October 2011 (UTC)

Statements about the production of neutrons fall under the born secret doctrine. Having said that, I am not certain you have correctly characterized the difficulty. Dualus (talk) 13:54, 19 October 2011 (UTC)

What nonsense. Neutron physics and neutron producing reactions have been declassified for decades. The sorts of technologies that can produce high fluxes of neutrons (accelerators, reactors, and fusion) are all mostly declassified (some very specific ICF applications are not, but they don't relate to the basic fusion processes). You don't know what you're talking about. --Mr.98 (talk) 13:28, 23 October 2011 (UTC)

You may be interested in Neutronium. ~AH1 ^(discuss!) 02:03, 19 October 2011 (UTC)

beaches in shantou

are the beaches in shantou,china all natural? are any parts of the waters man made.? The islands of Nan ao are the waters man made or natural? 24.146.215.97 (talk) 21:10, 18 October 2011 (UTC)

The Shantou Harbour (river mouth) has many rectangular beachfronts and channels, which would imply that at least part of the coastal region has been artificially shaped. I'm not sure what you mean by "man made water", but the island of Nan'ao is heavily forested, so the land itself is probably natural. ~AH1 ^(discuss!) 02:02, 19 October 2011 (UTC)

Successor to the Large Hadron Collider?

Is a successor to the Large Hadron Collider planned? Bubba73 ^{You talkin' to me?} 21:55, 18 October 2011 (UTC)

Well, I found the answer: Super Large Hadron Collider. Bubba73 ^{You talkin' to me?} 21:57, 18 October 2011 (UTC)

Then there's the Very Large Hadron Collider. And perhaps the Super Very Large Hadron Collider? Then I suppose they'll build one in orbit, encircling the entire planet at the equator... --Kurt Shaped Box (talk) 22:05, 18 October 2011 (UTC)

Which will be called the FGHC, where "GHC" means "Ginormous Hadron Collider"? Tonywalton ^Talk 22:28, 18 October 2011 (UTC)

It's the Superconducting Super Collider in the parallel universe where it was finished as planned:

The SSC's planned collision energy of 40 TeV was almost triple the 14 TeV of its European counterpart, the Large Hadron Collider (LHC) at CERN in Geneva. The SSC cost was due largely to the massive civil engineering project of digging a huge tunnel underground. The LHC in contrast took over the pre-existing engineering infrastructure and 27 km long underground cavern of the Large Electron-Positron Collider, and used innovative magnet designs to bend the higher energy particles into the available tunnel. [13]. The LHC eventually cost the equivalent of about 5 billion US dollars to build.

Count Iblis (talk) 23:50, 18 October 2011 (UTC)

Every multi-billion-dollar high-energy physics experiment is an entity unto itself. I don't think they can be easily compared. One possible "successor" to the LHC would be the International Linear Collider, which would have a lower collision energy than the LHC but much better control over the exact circumstances of the collisions, giving cleaner data. Another possibility is a muon collider. Whether these projects get funded depends in large part on what the LHC finds. -- BenRG (talk) 07:03, 19 October 2011 (UTC)

I propose we call the next one "the really, really, mind-boggling big frozen magnet thing which might pay us to put off having to tell people that dark matter is primordial intermediate mass black holes for a few more years." Dualus (talk) 14:25, 19 October 2011 (UTC)

Isn't that a pretty narrow way to look at it? As I understand, to recreate conditions from earlier in the universe, you need really high energies. That's just fundamental - and looking at those particles should be instructive, right? Wnt (talk) 00:20, 20 October 2011 (UTC)

I can recreate conditions from earlier in the universe with a camcorder. Dualus (talk) 03:48, 20 October 2011 (UTC)

I prefer the name "BFC-9000" --Carnildo (talk) 22:45, 21 October 2011 (UTC)