Wikipedia:Reference desk/Science

Welcome to the science section
of the Wikipedia reference desk.

skip to bottom

Select a section:

• Computing
• Entertainment
• Humanities
• Language
• Mathematics
• Science
• Miscellaneous
• Archives

Want a faster answer?

Main page: Help searching Wikipedia

   

How can I get my question answered?

• Select the section of the desk that best fits the general topic of your question (see the navigation column to the right).
• Post your question to only one section, providing a short header that gives the topic of your question.
• Type '~~~~' (that is, four tilde characters) at the end – this signs and dates your contribution so we know who wrote what and when.
• Don't post personal contact information – it will be removed. Any answers will be provided here.
• Please be as specific as possible, and include all relevant context – the usefulness of answers may depend on the context.
• Note:
  • We don't answer (and may remove) questions that require medical diagnosis or legal advice.
  • We don't answer requests for opinions, predictions or debate.
  • We don't do your homework for you, though we'll help you past the stuck point.
  • We don't conduct original research or provide a free source of ideas, but we'll help you find information you need.

Ready? Ask a new question!

How do I answer a question?

Main page: Wikipedia:Reference desk/Guidelines

• The best answers address the question directly, and back up facts with wikilinks and links to sources. Do not edit others' comments and do not give any medical or legal advice.

See also:

• Teahouse
• Help desk
• Village pump
• Help manual

July 28

Please identify this Dragonfly species

Please help identify this dragonfly species. The picture was taken in New Jersey on a concrete surface. The animal was just under three inches in length. μηδείς (talk) 04:49, 28 July 2011 (UTC)

My guess is this is a Common Whitetail, check the "adult female" in that article. --Jayron32 04:56, 28 July 2011 (UTC)

There are also several close matches at the genus Libellula, for example check the adult female example at Twelve-spotted Skimmer. --Jayron32 04:59, 28 July 2011 (UTC)

Funny, I told my informant she would get a quick response. Certainly looks like Libulella. I'll post her opinion after I call her tomorrow. Thanks. μηδείς (talk) 05:04, 28 July 2011 (UTC)

Thanks. She is satisfied it could be the female of either species. μηδείς (talk) 19:09, 28 July 2011 (UTC)

Resolved

Any research or speculation in medical literature on using radiation or chemotherapy to treat obesity?

Hi, I was wondering if cancer treatments like chemotherapy and radiation could be modified to treat obesity,(as well as infection). Has anyone seen anything written on this, pro or con, in the medical lit? -Thanks, Rich Peterson24.7.28.186 (talk) 06:02, 28 July 2011 (UTC)

I'm confused, are you sure you mean obesity? Obesity is not caused by any "agent" that could be targeted by chemo or radio therapy. How do you imagine those treatments could be modified to treat obesity? Vespine (talk) 06:12, 28 July 2011 (UTC)

It would be straightforward to treat obesity using chemotherapy or radiation: both of them tend to cause severe nausea, which predisposes against eating. The problem, of course, is that most people see the "cure" as worse than the disease. Looie496 (talk) 06:34, 28 July 2011 (UTC)

If the goal is simply to discourage appetite through prolonged, severe nausea, there are many other things one could consume that don't carry the risk of severe side effects (everything from permanent organ damage through to secondary cancers) associated with antineoplastic drugs or ionizing radiation. TenOfAllTrades(talk) 13:19, 28 July 2011 (UTC)

Sounds more like melting the fat away. You'd make billions. μηδείς (talk) 18:56, 28 July 2011 (UTC)

Well, thermal radiation (as well as thermal conduction and convection) is a rather old method of reducing weight, as in a sauna, but may cause weight loss mainly due to dehydration. StuRat (talk) 23:22, 29 July 2011 (UTC)

Horse manure

I saw this on the CBC web site:

But why is horse manure different? Why don't police have to stoop and scoop like everyone else? Sgt. Kristopher McCarthy, of the mounted unit, says that unlike dogs horse droppings have no harmful bacteria. "The difference between dogs and horses is that dogs eat meat and horses do not eat meat," McCarthy said.

Is it true that because horses are herbivorous, horse poop has “no harmful bacteria”? Follow-up question: what about humans who are vegan, does their poop have no harmful bacteria? Mathew5000 (talk) 12:19, 28 July 2011 (UTC)

No, harmful bacteria originate from external sources - they are deposited post deffication. The digestive tract is a pretty harsh environment for bacteria to survive, so only a select group of bacteria can do so. That being said, a carnivorous diet should provide a more nutritious bacteria culture. The point is that, the feces only becomes hazardous after defecation with the progression of time.I'd be more worried about deseases and other-nonbacterial organism that can accompany the feces. I am not a biologist, I am confident in my answer, nonetheless I welcome correction. Plasmic Physics (talk) 12:47, 28 July 2011 (UTC)

Seems like a case of basically right answer, but for the wrong reasons. This does ring true "Within two to three days manure will just dry out and blow away, very similar to clippings of grass." Also my wp:or indicates that carnivores do have worse-smelling feces than herbivores. SemanticMantis (talk) 14:02, 28 July 2011 (UTC)

The stomach is a harsh environment for most types of bacteria, but the lower parts of the digestive system are very hospitable. The digestive system of a horse in fact contains huge quantities of bacteria, and the horse depends on them to survive. In common with other ruminants, the only way they can digest cellulose is by allowing bacteria to ferment it in a structure called the cecum. The large intestine is also massively colonized by bacteria, as it is in all mammals. Looie496 (talk) 17:02, 28 July 2011 (UTC)

And even with all of that, horses pass 3/4 of their dinner undigested. --jpgordon^{::==( o )} 18:14, 28 July 2011 (UTC)

I used to have a neighbour who had a rather unpleasant method for dealing with dog feces on his backyard lawn. He would simply irrigate the lawn, feces and all, and then mow the lot. It's unpleasant due to the horrific smell drifting over the fence. Plasmic Physics (talk) 14:40, 28 July 2011 (UTC)

I can see why he's no longer your neighbor... Whoop whoop pull up ^{Bitching Betty | Averted crashes} 02:44, 31 July 2011 (UTC)

Horse manure can be fairly disgusting also, and the police are not unaware of that. I vaguely recall there was one protest in Chicago that they apparently must have disapproved of (maybe it was against the drug war) - think it was around the 96 DNC - which they insisted to "crowd control" on horseback. And they must have fed those horses every morsel they could cram down, because they (the horses that is) defecated continuously for the entire short route. The crowd thus had to keep on its toes, but I'd say the joke was on the police in the end, who ended up having to keep their horses in a neat little line for what seemed like hours as some speakers went on at great length ... all the while accumulating a reeking outdoor toilet behind them of positively epic proportions. Now I'm not entirely sure this was the reason, but Chicago eventually started requiring horse diapers in many cases. [1] Wnt (talk) 14:57, 28 July 2011 (UTC)

I guess you linked to that website about the diaper bit but it actually says horse urine smell is a bigger problem then the manure:

According to Sam, horse urine "smells like pure ammonia." He literally threw up one day because of the overwhelming odor, and he spent the rest of the summer with Vicks VapoRub under his nose, all because of the urine smell ("Shit actually doesn't smell that bad. I'd rather clean horse manure than people manure.").

Nil Einne (talk) 08:27, 29 July 2011 (UTC)

Keep in mind that the reason we have pooper-scooper laws is because of hysteria about parasites (hookworms, tapeworms and roundworms) being transmitted to babies playing with dog feces. It was never about bacteria. - Nunh-huh 21:17, 29 July 2011 (UTC)

Baking powder

Baking powder was not around during the colonial days. It was invented during the middle to late 1800's. What did the colonial women use to make cakes rise? If anyone can answer this, I would be grateful. — Preceding unsigned comment added by TerrDA (talk • contribs) 13:30, 28 July 2011 (UTC)

Baking powder#History Plasmic Physics (talk) 13:46, 28 July 2011 (UTC)

Baking powder is a leavening agent; that article lists several alternatives, including mechanical (whisking) leavening. The "history" section of the cake also talks about various pre-baking-powder cakes and cake-like desserts. It's also noteworthy that lots of cultures used, and use, unleavened foods, like pastries, fritters, or dumplings, in the role that you might expect cakes to take in modern western cuisine. -- Finlay McWalter ☻ Talk 13:52, 28 July 2011 (UTC)

Baker's Yeast has been used since at least the ancient Egypt, possibly much longer. Dauto (talk) 16:09, 28 July 2011 (UTC)

Baking soda predates baking powder, but probably the most common way of leavening a cake at that time was to use beaten egg whites -- that's still the method used for making sponge cakes. Looie496 (talk) 16:53, 28 July 2011 (UTC)

Leavening can happen with natural airborne yeasts as this recipe attests. You just need to leave the dough to stand for a few days. See also Sourdough; "Sourdough starter is made with a small amount of old dough saved from a prior batch, and is sometimes called mother dough or chef. This small amount of old-dough starter contains the culture, and its weight is increased by additions of new dough and mixing or kneading followed by rest or leavening periods. A small amount of the resulting dough is then saved to use as old-dough starter for the next batch. As long as this starter culture is fed flour and water weekly, it can stay at room temperature indefinitely." The article also says that cultured yeast followed the discoveries of Louis Pasteur; before that, Barm from brewing was used. Alansplodge (talk) 19:12, 29 July 2011 (UTC)

Then there's salt rising bread, intriguingly made using bacteria better known for food poisoning and gas gangrene, which are mysteriously docile when handled this way. Wnt (talk) 07:02, 30 July 2011 (UTC)

Lovely mystery mushroom

Does anybody recognize what this mushroom is? It was spotted while hiking Freeman Creek in the southern Sierra Nevada. --jpgordon^{::==( o )} 14:26, 28 July 2011 (UTC)

Given the location in the Sierras, Calvatia sculpta seems a good possibility. But I'm no expert. Deor (talk) 15:09, 28 July 2011 (UTC)

That looks vaguely reminiscent of the puffball Calvatia sculpta, from about the right area, not close enough to convince me. Wnt (talk) 15:15, 28 July 2011 (UTC) -- note I added this without seeing the previous comment. Interesting we both picked the same thing - in any case I don't mean to naysay the previous poster. Wnt (talk) 15:16, 28 July 2011 (UTC)

I'd venture Calvatia sculpta is correct. It was in the right elevation range in the right location. Cutting one in half to see the puffball insides would be a good way to tell, I suppose, though there doesn't seem to be much to confuse it with. (No, I'm not planning on either eating one or destroying one; they're too pretty on the forest floor.) Thanks! --jpgordon^{::==( o )} 15:25, 28 July 2011 (UTC)

"It was spotted while hiking" - now that is impressive. AndrewWTaylor (talk) 16:14, 28 July 2011 (UTC)

This is the Science Refdesk. Relativity applies here. Smile and the world smiles with you - hike and the world hikes against you. Wnt (talk) 18:04, 28 July 2011 (UTC)

If we could get a picture of that mushroom's backpack it might help to identify it. Bus stop (talk) 18:20, 28 July 2011 (UTC)

I wonder if he's ever shot a picture of a mushroom wearing his pajamas. :-) StuRat (talk) 23:13, 29 July 2011 (UTC)

Knowing the photographer, he has shared his pajamas, yes. --jpgordon^{::==( o )} 15:37, 30 July 2011 (UTC)

Dehumidifier in the desert

I was emptying out my dehumidifier when I had this idea: in places where open water is scarce, like in the Sahara region, why don't they use dehumidifier-like things to extract the water from the air? I understand that the air in those places is obvious not very humid, but even with 1% humidity, one cubic metre of air would yield 10 l of water, which is enough for one person to drink, and maybe even cook if used frugally. Solar power could be used to power the dehumidifier where electricity is expensive or unavailable. Has this been tried before? I'd like to read about it if it has. Thanks in avance. — Preceding unsigned comment added by 118.98.102.191 (talk) 18:16, 28 July 2011 (UTC)

I think you're high by several orders of magnitude: the water content would be measured, even at high RH, in terms of grams of water per kilogram of air. Acroterion (talk) 18:21, 28 July 2011 (UTC)

Yes, see our humidity article. Air at '100% humidity' isn't all water (obviously), but instead air with the maximum possible amount of water vapour present at that particular temperature and pressure - any surplus vapour would condense out as mist etc. AndyTheGrump (talk) 18:27, 28 July 2011 (UTC)

The BBC Weather page for Riyadh gives tomorrow's temperature as 44C with RH of 12%. Using this table (linked from the humidity article) shows that the air there will contain ~7g of water per cubic metre - about a teaspoonfull. -- Finlay McWalter ☻ Talk 18:35, 28 July 2011 (UTC)

But the amount of air which will go through the dehumidifier is far more than a single cubic meter. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 02:40, 31 July 2011 (UTC)

Air well (condenser), Dune technology μηδείς (talk) 18:55, 28 July 2011 (UTC)

Here's a common method to capture water in the desert: dig a pit about one metre across and deep, then place an open empty water bottle in the centre of the pit. Spread a plastic tarp over the entire pit and fasten it using pins into the sand. Place a small rock in the centre of the tarp over the bottle, and the moisture will rise onto the tarp, condense and fall into the bottle. ~AH1 ^(discuss!) 23:24, 28 July 2011 (UTC)

One practical problem with using a dehumidifier or air conditioner to collect water in the desert is that it would immediately evaporate. For a given drop of water, you might only have seconds to get it into a sealed container before it would become vapor. This would especially be a problem on a small scale. StuRat (talk) 23:10, 29 July 2011 (UTC)

A dehumidifier is essentially a refrigerator - it only works if the air gets cold enough that dew would form naturally (below the dew point). Given that the water condenses in some refrigerated space, from refrigerated air, it shouldn't re-evaporate afterward. But since temperatures in deserts often vary greatly, it may be possible to use some apparatus that doesn't consume energy to accomplish this task. Wnt (talk) 07:01, 30 July 2011 (UTC)

Horses whinnying at bicyclist

More than once, while passing a horse going in the opposite direction on a country lane in the UK, the horse has whinnied. Has anyone else experienced this? Does this suggest that some horses think of bicycles plus rider as a kind of horse? 92.24.133.177 (talk) 18:44, 28 July 2011 (UTC)

Could also be fear of the sort Temple Grandin describes with startled cows, see Animals in Translation, as well as Monty Roberts. μηδείς (talk) 19:15, 28 July 2011 (UTC)

I've had horses respond to me as a cyclist producing Horse Noises. Nothing too unusual. ~AH1 ^(discuss!) 23:17, 28 July 2011 (UTC)

What do you mean by horse noises? 92.29.113.104 (talk) 10:19, 29 July 2011 (UTC)

Horse noises. μηδείς (talk) 20:20, 29 July 2011 (UTC)

Trans fat in British soft margarine

When I buy a tub of margarine in the UK, what are the chances of it containing more than trace amounts of trans fat? 92.24.133.177 (talk) 19:43, 28 July 2011 (UTC)

Here in Canada, any processed food containing less than 0.5 grams of trans fat per indicated serving amount can be advertised as "zero trans fat". Always check the nutrition facts. ~AH1 ^(discuss!) 23:16, 28 July 2011 (UTC)

Trans fat is never shown in the nutrition label in the UK. The manufacturers and government regulators keep us in the dark. 92.29.113.104 (talk) 10:14, 29 July 2011 (UTC)

In that case, the best you can do is look for hydrogenated vegetable oils in the ingredients list, unless a reliable lab has test results available, or the company's own webs site clarifies matters. StuRat (talk) 23:04, 29 July 2011 (UTC)

Wow. According to this some politicians in Britain say they're OK if they only make up "1% of total energy". But it also says that some members of the British Retail Association like Tesco have removed it from own-brand foods. Maybe that's a lead? I oppose nanny-state regulation but I do think something sold as food should be made out of food, not something chemically processed at high temperatures over a catalyst into substances not naturally encountered in the diet. Wnt (talk) 06:47, 30 July 2011 (UTC)

I'm opposed to a "nanny state", too, but, in order for people to be allowed to make their own decisions, they do need information, such as whether their food contains this poison, or not. StuRat (talk) 04:37, 31 July 2011 (UTC)

Hey y'all, remember the famous saying, "The dose makes the poison". Sure enough, in large quantities trans-fats are harmful, but there's no harm in consuming small amounts of trans-fat. This whole issue has been vastly overblown by the so-called "healthy food movement" (which IMHO is more concerned with opposing capitalism than with improving public health). Anyway, I often eat Oreo cookies and other stuff like that, and I've never experienced any ill-effects from it. Yes, more info might be in order here, but we must keep in mind that trans-fats are not a "poison", just an ingredient that's not healthy for you in large amounts (but perfectly OK in small amounts). As another saying goes, "Everything in moderation". 67.169.177.176 (talk) 05:13, 31 July 2011 (UTC)

Well, I wouldn't expect any obvious effects from trans-fats until your first heart attack. (Trans-fats actually cause me to get acne, but that's apparently just me.) StuRat (talk) 06:08, 31 July 2011 (UTC)

And if you keep trans-fat consumption to a low level, I bet you never will. 67.169.177.176 (talk) 08:38, 31 July 2011 (UTC)

Right, but this requires knowledge of which foods contain trans-fats, and in which quantities; hence this question. StuRat (talk) 18:33, 31 July 2011 (UTC)

Apart from health issues, IMHO eating trans fats makes me get an "old stopped-up sink taste" in the back of my throat. (Supposedly humans don't have taste/smell like receptors in the back of the throat like other mammals but I don't believe it) Wnt (talk) 20:37, 1 August 2011 (UTC)

Chocolate for treating depression

Does any study indeed treated depressed people with chocolate to test its anti-depressing effect? (kind of 100 gr. black chocolate in the morning). Quest09 (talk) 20:33, 28 July 2011 (UTC)

Yeah. It doesn't work so well. Please see PMID 16546266. 99.39.4.220 (talk) 21:08, 28 July 2011 (UTC)

A placebo might work, though depression is not purely physiological. ~AH1 ^(discuss!) 23:13, 28 July 2011 (UTC)

I don't know about an official study, but I think most married men would agree that it works on their wives... Beeblebrox (talk) 19:35, 30 July 2011 (UTC)

Very nice, Beebles. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 02:49, 31 July 2011 (UTC)

Should I get a food processor, mixer, or something else?

My dad doesn't want to have his two unstable teeth pulled for a full denture, but he can't chew vegetables as a result. I'm thinking a food processor would make such an important food group more palatable. Do you agree? I don't think a mixer would be as appropriate? Imagine Reason (talk) 23:08, 28 July 2011 (UTC)

Maybe try a juicing machine for some vegetable juice, such as brocoli? ~AH1 ^(discuss!) 23:11, 28 July 2011 (UTC)

I wouldn't wish a juicer on anyone other than convicted war criminals. You feed the thing £10 of nice fruit and veg and it emits a pint or so of a murky fluid that tastes downright suspicious and causes alarming gastrological disturbances, together with a completely impossible volume of fluffy brown loft insulation. Then you have to spend half an hour cleaning weird paste from the little ducts and sluices in the machine, and another half hour removing tiny seeds from its spinny juicing disc. This explains why charity chops are full of shiny new juicers (on the same shelf as the bread-flavoured-goo-makers). -- Finlay McWalter ☻ Talk 23:32, 28 July 2011 (UTC)

I have an immersion blender which came with a food-processor add-on (so you can chop up veg to make things like soup or salsa). I mostly use it to make smoothies, and my mum uses hers to make creamed (that is, fully liquid) vegetable soups. Its best feature is that it's trivial to clean (one runs the immersion part under a running tap), which means you're happy to use it very frequently (a juicer, in contrast, is torment to clean). In my experience toddlers will happily drink veg (things like carrots) if it's hidden in a smoothie; mayhap your tooth-challenged eldster will feel similarly. -- Finlay McWalter ☻ Talk 23:22, 28 July 2011 (UTC)

Juicers give excellent results from carrots and grapes. Urrghl. But were I starving I'd prefer a blender. μηδείς (talk) 04:55, 29 July 2011 (UTC)

They work pretty well with apples too. 67.169.177.176 (talk) 05:16, 31 July 2011 (UTC)

How about using a potato masher on the cooked vegetables? 92.29.113.104 (talk) 10:16, 29 July 2011 (UTC)

This is kind of what I'm looking for. I don't believe in juicers, because they leave behind much of the nutrients. Grapes are high in fructose as well. Imagine Reason (talk) 14:49, 29 July 2011 (UTC)

Try this: [2]. ~AH1 ^(discuss!) 20:11, 29 July 2011 (UTC)

Actually, except for the fiber of a vegetable's cell walls, juicers do extract the large portion of the water soluble nutrients. μηδείς (talk) 20:17, 29 July 2011 (UTC)

Right, so it follows that for those people who are concerned that they are getting too much fiber in their diets, juicers are appropriate. The rest of us should avoid them. StuRat (talk) 23:01, 29 July 2011 (UTC)

I think the OPs father would more enjoy his vegetables chopped up or mashed up into small pieces that did not require chewing, rather than just making them into a soup as a blender or liguidiser would do. So I suggest either chopping then finely or using a potato masher as previous suggested. And few people get enough fibre, so it would be unhealthy to discard the fibre by using a juicer. 92.29.124.70 (talk) 12:28, 30 July 2011 (UTC)

• There are many healthy, delicious things you can make with veggies in a food processor. Ajvar or Baba Ganoush can be used as a templates for further experimentation. By varying the base ingredients and spices the possibilities are endless. Another thing you can do is to sweat carrots, onions, celery, etc, then puree them in the processor and incorporate them into another dish. This is a great way to make various kinds of soups and bean dishes. If its hot out Gazpacho can be quite refreshing. Beeblebrox (talk) 19:45, 30 July 2011 (UTC)

July 29

Radioactive casting

When radioactive metals are molten down and cast into ingots, how is the critical mass taken into account when melting down the metal? How is the process different from handling non-radioactive metals? What shapes are typical for radioactive ingots? I have an idea, for a shape: hexagonal column with a hole through the middle, the diameter of the the hole being proportional to the fissile cross section. Plasmic Physics (talk) 03:46, 29 July 2011 (UTC)

I think nobody ever dared to produce an ingot larger than the critical mass of the fissible isotope. As a lot of radioactive elements are not undergo fission for most of the radioactive isotopes you do not have this problem.--Stone (talk) 08:23, 29 July 2011 (UTC)

Surely, more than one ingot's worth of metal is melted down at once? Plasmic Physics (talk) 11:08, 29 July 2011 (UTC)

Hollow spheres and columns are often used for storing very high grade fissile material for the very reason you've mentioned — the air gap increases the critical mass considerably. --Mr.98 (talk) 10:26, 29 July 2011 (UTC)

What is the safety margin, by how much percent is the ingot from critical mass? How about radioactive foil, possibly laminated between layers of wax, for the more radioactive metals? Plasmic Physics (talk) 11:08, 29 July 2011 (UTC)

The requirements are quite detailed and baroque. Calculating critical masses requires a lot of careful work based on the geometry, composition, and neutron moderation or reflection issues. I'm not sure there is one "safety margin" figure. The NRC has all sorts of regulations and approved containers and etc. and these have been designed and reviewed by great numbers of engineers.

Wax is probably not a good thing to use in a radioactive context, because it likely would slow neutrons down (acting as a moderator), which actually increases induced radioactivity and fissioning. --Mr.98 (talk) 11:40, 29 July 2011 (UTC)

How about a silicon based wax? If not, what would you use to protect the foil surface from oxidation, while simultaneously acting as a spacer, and must be flexible? Plasmic Physics (talk) 15:07, 29 July 2011 (UTC)

What your looking for are things like the "upper sub-critical limit" etc. This resent document goes into the Canadian regulations in some detail. Nuclear Criticality Safety Regulatory Document RD-327. This is not to say however, that following them to the letter will avoid you severely depressing your local real estate values and getting the neighbours grumpy. --Aspro (talk) 11:46, 29 July 2011 (UTC)

I was hoping for a percentage. For instance, the neutron flux must be no less than 40% from critcality at any point within the ingot. Plasmic Physics (talk) 15:07, 29 July 2011 (UTC)

Having a molten fissile elements with more than a critical mass just sounds like such a bad idea. There are fission reactors that use uranium metal alloys, but the most common fissile fuel is uranium oxide (UO2), which is produced as a powder (from U3O8 and UF6), packed into molds and sintered together in a furnace. The production process never requires molten uranium. For many of the same reasons that one would have to be careful about molten uranium, there are presumably very detailed rules for the handling and concentrations of such powder to avoid a criticality event; however, the powder has the advantage that it can be handled and formed at room temperature. Many of the alternatives of uranium oxide fuel, such as uranium nitride, uranium carbide, and plutonium oxide, are similarly formed via powders rather than as pure metals. Dragons flight (talk) 16:01, 29 July 2011 (UTC)

Besides the whole critical mass issue it is in any case a really bad idea to melt metallic Uranium because due to its pyrophoricity it requires very little provocation to ignite it.

Post graduate study in the renowned medical colleges in U.S.

After we are done studying the under graduate classes for M.B.B.S. , we have to have the M.D. degree. So are there scholarship oppurtunities for deserving students to have post graduate study in the renowned medical colleges?113.199.183.176 (talk) 04:01, 29 July 2011 (UTC)

Try checking the websites of those specific colleges, or Google American medical scholarships and Nepalese medical scholarships for your country of origin, based on your IP address. ~AH1 ^(discuss!) 20:08, 29 July 2011 (UTC)

Brain in the heart

There have been several articles on the web spreading this rumor? Are there any reliable sources that talk about heart thinking and memorizing?--Almuhammedi (talk) 08:09, 29 July 2011 (UTC)

Sounds like nonsense. Anyway as for RS, the best I could find is [3] which appears to have been published [4]. Although for some reason on the Royal College of Psychiatrists website, glancing thru it and seeing discussions on things like the human 'spirit' and bioelectromagnetic communication between people doesn't exactly give me confidence in it, perhaps partially explaining why it was published in the The Arab Journal of Psychiatry Nil Einne (talk) 08:53, 29 July 2011 (UTC)

It doesn't take much googling to find people claiming that this discovery that our brains are "really" in our hearts is the literal fulfillment of a Qur'an passage. Maybe this is the Islamic equivalent of the "Lost Day" urban legend. APL (talk) 09:09, 29 July 2011 (UTC)

Seems to have root in this research here where it is apparently discovered that the heart has a small nerve cluster that is used to control and regulate the heart. Probably because the researcher seems to have dubbed this a "little brain", all the crazy pseudo-scientists have latched onto it and made up all manner of crazy stories.

However this nerve cluster is obviously not sophisticated enough to do anything the potions and crystals crowd says it does, if only for the fact that it's tiny. Ants have brains almost ten times larger. APL (talk) 09:02, 29 July 2011 (UTC)

The heart does have a system of cardiac ganglia (little clumps of neurons). Here's a diagram showing where all the cardiac ganglia are.[5] There are neurons connected to the heart for several reasons. Some of those neurons are a part of the parasympathetic nervous system, a system of neurons that regulates the body's functions when the body is at rest. Other of the heart's neurons are part of the sympathetic nervous system, which prepares the body for a fight-or-flight response by, for example, speeding up the heart. And still other of the heart's neurons are a part of the sensory system. But saying that the heart "has a brain" just because it has some neurons is really an exaggeration. The heart's neurons just deal with low-level bodily functioning. There really aren't enough neurons involved to call what they do "thinking". It just looks like some new age types have exaggerated, twisted, and adapted something that started off as a bit of scientific reality to meet their own beliefs and viewpoints, similar to how the flaky quantum mysticism grew out of the scientific quantum mechanics. Red Act (talk) 09:58, 29 July 2011 (UTC)

There's a little more to it than that. The heart has a sort of central controller called the sinoatrial node, which serves as pacemaker for the whole system. It is connected to other parts of the heart by very specialized muscle cells called Purkinje fibers, which function almost like nerves. But I wouldn't myself call this a "brain", and I don't see anything mystical about it. Looie496 (talk) 16:29, 29 July 2011 (UTC)

Think of how clever a gnat is, with such a tiny brain. We can't rule out that there is some thought in the heart and other ganglia. There is an operation, vagotomy, which affects the vagus nerve further away from the brain than the heart, which has subjective effects on a person. The enteric nervous system is also dubbed a "second brain". Vagus nerve stimulation is even said to have anti-depressive effects. I don't think it's unreasonable to suppose that all the little (and large) ganglia throughout the body are part, one way or another, of "thinking", in some sense of the term. Of course, none of this changes that the biggest lump of grey matter is in the head. Wnt (talk) 17:08, 29 July 2011 (UTC)

The brain, heart and lungs are codependant. That's about it. ~AH1 ^(discuss!) 20:04, 29 July 2011 (UTC)

"We can't rule out" coupled with a total lack of evidence and a total lack of connection to what we do understand (in this case about the necessity of sense perception for thought) is what is called "faith". This, however, is the Science reference desk. μηδείς (talk) 20:12, 29 July 2011 (UTC)

Absence of evidence is not evidence of absence. And I described evidence - vagus nerve stimulation as an antidepressant. Of course, the theory to explain that may or may not involve any sort of "thought" in the heart, but it provides a starting point for new hypotheses. Science tells us we should keep an open mind and not declare that all thought (defined how?) must be in the brain. Wnt (talk) 20:31, 29 July 2011 (UTC)

Also note that according to James–Lange theory the heart rate itself is an integral part of the process by which we feel fear. Wnt (talk) 20:40, 29 July 2011 (UTC)

"Absence of evidence is not evidence of absence" is very shaky way to advocate believing in any specific thing. Absence of evidence is also an absence of reason to believe. (excepting religious faith.)

Besides, let's not forget that many individuals have had their hearts removed entirely and replaced with either someone else's heart or even a machine. Do they normally report a change in personality or thought processes? I've never heard of such a thing. APL (talk) 21:07, 29 July 2011 (UTC)

Utter bollocks. Axl ¤ [Talk] 10:10, 30 July 2011 (UTC)

Thanks for interactive explanations. One more question relevant; what are the current (approx) records of those lifespans who survived with artificial heart? Had some suffered brain problems as stated in the webs? By the way; not only some Muslims exaggerate with these rumors but some others as well (perhaps creationists in general are looking after such hopes to support their belief).--Almuhammedi (talk) 19:33, 30 July 2011 (UTC)

Curious anecdote: [6] Wnt (talk) 05:30, 5 August 2011 (UTC)

Why do horses whinny?

What is the purpose or function of whinnying, and other horse noises? I know nothing about horses. 92.29.113.104 (talk) 10:23, 29 July 2011 (UTC)

See communication. Cheers. --Jayron32 12:29, 29 July 2011 (UTC)

"Our analysis of the acoustic structure of whinnies of 30 adult domestic horses (ten stallions, ten geldings, ten mares) revealed that some of the frequency and temporal parameters carried reliable information about the caller’s sex, body size and identity." from this 2009 article. Sean.hoyland - talk 12:43, 29 July 2011 (UTC)

Is whinnying different from neighing, or are they just two different names for the same thing? Are these the only noises horses make? 92.29.113.104 (talk) 17:30, 29 July 2011 (UTC)

I don't know if equestrians distinguish whinny from a neigh. For instance, I think whickering is considered fairly distinct from either previous term, but wiktionary [7] just defines it with 'neigh'. I do know that many people can distinguish several types of dog bark, e.g. some barks loosely communicate 'hello, let's play', while other indicate 'back off, or I will bite'. --The point is, there are many, many vocalizations that horses make, and they can communicate many different things. I think this is more important to recognize than what names we call these sounds. Probably the best way to learn is to spend more time around horses and equestrians ;) SemanticMantis (talk) 18:45, 29 July 2011 (UTC)

Mpemba effect

Are there any new studies explaining this phenomenon in details?--Almuhammedi (talk) 13:06, 29 July 2011 (UTC)

this list has articles dating from as early as 1969 and as recently as 2009. --Jayron32 13:13, 29 July 2011 (UTC)

In the hope of pulling in other readers, we should explain that this is the disputed? observation that "hot water freezes faster than cold". I should say that what confuses me about it is: if 35 degree C water freezes faster than 5 degree C water, what temperature is it before it freezes? Isn't it 5 degrees C itself sometime? Though the "convection" explanation from the article might explain this... Wnt (talk) 20:25, 29 July 2011 (UTC)

You really need to read the article. The claim is not "disputed", the effect is just not what you said it is, that "hot water freezes faster than cold" in all cases. If the effect were simply that "hot water freezes faster than cold" than it would be essentially wrong. What the Mpemba effect covers is a narrowly constructed set of conditions where warmer water would be said to freeze faster than colder water would. It isn't a universal effect, but rather a minor effect in a well-constructed scenario. If applied to its correct conditions, it works, and therefore isn't generally disputed. There is some dispute about how important the effect is in the field of thermodynamics, but it is a real, repeatable experiment, if you do it right. --Jayron32 23:27, 29 July 2011 (UTC)

"Evaporation" also addresses that. The 35C water will eventually cool to 5C, but by then there might be a lot less of it.

If you ask me, this part of the effect is almost certainly why the old trick of tossing a pan of hot water into the air on a cold day will make snow, but a pan of cold water often won't. The tiny droplets in the air have a very large surface-area to volume ratio. APL (talk) 04:41, 30 July 2011 (UTC)

Transmitter question

what is the full form of STT in STT 433 MHz Transmitter? — Preceding unsigned comment added by 42.104.43.155 (talk) 14:30, 29 July 2011 (UTC)

Not sure, is that its brand name? Is it the company that operates the transmitter? Looking at the wikipedia article STT my best guess would be Singapore Technologies Telemedia or possibly Suomen Tietotoimisto. --Jayron32 14:46, 29 July 2011 (UTC)

A Google search says that it means "Sunrom Technologies Transmitter" -- Sunrom also makes a corresponding receiver called the STR-433. Looie496 (talk) 16:23, 29 July 2011 (UTC)

Another possibility: PTT is very common (especially in old-fashioned handsets, or in HAM radio gear). "PTT" means "push to talk" or "press to transmit" - i.e., hold down a trigger-button while speaking to transmit. STT, on the other hand, can stand for "Speak to Transmit" - in other words, instead of a button, you just talk into the handset or microphone, and it automatically transmits. You're always potentially transmitting (though you probably have a squelch circuit that may or may not be tunable). This mode is also known as "speakerphone," "squelch," "vox", "always on," "hot mic," and so forth. Nimur (talk) 18:15, 29 July 2011 (UTC)

See this document. There's really no doubt that it means "Sunrom Technologies Transmitter". The device is a little $5 chip used to build remote controls. Looie496 (talk) 22:11, 29 July 2011 (UTC)

How did Dewar make his flask

I saw a PDF available for $35 from the American Chemical Society, but wasn't going to pay that much just to satiate my curiosity. I just want to know how James Dewar constructed his Dewar flasks in the 1890s. I saw on the first page of the ACS paper how the larger outer flask, that had a tube near the neck for evacuating, was cleanly cut using a wire running a higher current and then pouring cold water on it, after which the smaller flask was placed inside and the outer flask melted back together, and I can imagine that glassblowers melted some glass to seal the portion between the two necks at the top, but I'm wondering how he quickly sealed off the tube at the top after having pumped out all the air. The pressure difference between the inside of the vacuum section and the room in which you're working would have made it hard to just use hot tongs and expect the glass to seal the hole nice and cleanly without molten glass getting sucked in and in general just getting a mucky mess (or just blowing a hole in the neck while you're heating it and ruining your vacuum). 20.137.18.50 (talk) 14:48, 29 July 2011 (UTC)

It's pretty easy to heat a glass tube and get it to constrict and seal under vacuum rather than the glass getting sucked back into the tube. See for example this tutorial. DMacks (talk) 15:01, 29 July 2011 (UTC)

The key point is that glass being, well, a glass doesn't have a single sharp melting point where it goes from completely solid to completely liquid. Instead it has a range of temperatures where it gradually softens. If you apply just enough heat, you can get it soft enough to deform and fuse, but not so soft it loses all structural integrity. So if you melt a glass tube under vacuum, the center of the zone you are heating, being the softest, will collapse inwards and it will do so without deviation as both ends of the tube are under vacuum. The areas adjacent to the center of the zone will be less deformable, and will resist getting sucked inward. And since it's not completely liquid, the adjacent areas will support the more deformable center zone. -- 174.24.213.112 (talk) 15:48, 29 July 2011 (UTC)

(ec) The last page of the document you (IP 20.137.18.50) linked contains this paragraph (hope this helps): "If new flasks are used it is unnecessary to clean them with cleaning solution, but they should be washed with stannous chloride, rinsed and silvered. Rinsing and silvering should be done with a small quantity of liquid, by shaking and rotating, rather than filling the entire space between the walls. Two or three coats of silver are desirable. The silver is then washed out of the evacuating tube with cotton soaked with very dilute nitric acid, the entire flask rinsed several times with water, and the evacuating tube necked down at F for sealing off. Evacuation is carried out at about 400° in the electric furnace over a period of thirty-six hours, by means of a mercury vapor pump and liquid-air trap. Evacuation for a shorter period of time fails to outgas the silver completely and the flask deteriorates rather rapidly. Sealing off is done as soon after turning off the heat as possible. Our practice is to anneal two of the Dewar flasks at once (this requires the moving of one while hot from one ring stand to another already in the furnace) and later to evacuate them together." -- Scray (talk) 15:17, 29 July 2011 (UTC)

Thanks, Scray. I didn't see that part. I wouldn't have thought they'd evacuate that way. I thought they would just attach a tube and turn on a vacuum pump (which I assumed they had in the 1890s). I'm going to have to search 'mercury vapor pump' and 'liquid air trap' now so I can at least visualize what they're talking about. 20.137.18.50 (talk) 16:50, 29 July 2011 (UTC)

No problem - I realized that you couldn't have seen that page without paying the fee; I have full access (being an academic). I'm glad that helped. -- Scray (talk) 22:22, 29 July 2011 (UTC)

To me, "mercury vapor pump" says diffusion pump, but those weren't invented until 1915. --Carnildo (talk) 00:51, 30 July 2011 (UTC)

Dewar was a technician of absolute genius quality. He seems to have been the first human to have devised a vacuum flask, (decades before 1915) with glass surfaces coated with mercury, to achieve the greatest possible thermal isolation of extremely low temp substances. Edison (talk) 02:59, 30 July 2011 (UTC)

Possibly a Sprengel pump 75.41.110.200 (talk) 03:09, 30 July 2011 (UTC)

Palladium

Why is palladium able to store so much hydrogen? --134.10.113.198 (talk) 16:30, 29 July 2011 (UTC)

See Palladium#Hydrogen_storage and Palladium hydride for a general overview. This google search turns up a veritable shitload of good sources which explore the mechanisms behind hydrogen absorption onto Palladium. This article goes into some really good details of the mechanism. You do need to be a little careful in your research, as the hydrogen/palladium system was the basis for the whole cold fusion bullshit back in the day; but also be aware that the system also has its more commonplace uses, like in catalytic hydrogenation, either as finely palladium on carbon, or in Lindlar's catalyst --Jayron32 17:02, 29 July 2011 (UTC)

Nightmares and Nightterrors.

Exactly what is the purpose of nightmares and nightterrors. --86.45.162.217 (talk) 20:14, 29 July 2011 (UTC)

I assume you aren't falling into the error of attributing purpose to evolution, but merely employing a common though technically incorrect idiom? That aside, not every biological phenomenon is a beneficial, selected character; some are just by-products of other biological aspects of an organism - to draw a computing software analogy, they're a bug, not a feature. {The poster formerly known as 87.81.230.195} 90.201.110.58 (talk) 21:38, 29 July 2011 (UTC)

This is OR, but I have most commonly had nightmares when something is wrong, most often I'm either too hot or having trouble breathing efficiently because something is covering my head. In those cases it seems like one function of the nightmare is to cause awakening. Looie496 (talk) 22:05, 29 July 2011 (UTC)

Like regular dreams, one possibility is that they allow us to review things that happened previously (bad things, in this case) to decide on alternative courses of action, or to imagine future scenarios, and develop a plan of action, should they occur during waking hours. Note that "things which happened" don't have to have been real, they could have been watched in a movie or on TV or merely been heard about. StuRat (talk) 22:48, 29 July 2011 (UTC)

This is like asking "what is the purpose of schizophrenia?" Sometimes there is a cause that can be pointed to, but purpose? I don't think so. Beeblebrox (talk) 23:16, 29 July 2011 (UTC)

Nightmares and night terrors seem to be an instantiation of free-floating anxiety. Will a tornado or earth quake destroy all one's possesions? Will things turn out all right in general? Will a burglar break in? Will interpersonal relationships prosper? Will travellers get where they are bound without accident? Will there be enough money for retirement? Will the world's geopolitical affairs turn out ok? Will they ever get the debt limit increased in the US? Is the mole cancerous? Will one's job lead to advancement? Will the school course result in a good grade? Will one go to heaven or hell in the afterlife? Gasp! Wake up in a cold sweat!Edison (talk) 01:33, 1 August 2011 (UTC)

Couldn't he get prosthetic implants?

Look at Nick: http://www.youtube.com/watch?v=1zzTFrmEQh4&feature=autoplay&list=WLE9874D88A2291309&index=42&playnext=2

If I were in his situation, I'd move heaven & earth to get implants of prosthetic arms and legs and never tire of that pursuit until I have them installed.

Would it be possible to have four prostheses installed on him? What's stopping him for having them? --70.179.165.67 (talk) 20:42, 29 July 2011 (UTC)

I can't speak to individual cases, but with prosthetic limbs costing upwards of $100,000 US per limb, expense might be a factor. - Nunh-huh 21:58, 29 July 2011 (UTC)

Do they still make wooden legs? Seems to me that would be far cheaper and better than nothing if you couldn't afford a very expensive high-tech leg. Nyttend (talk) 01:12, 30 July 2011 (UTC)

It looks like his situation is very different from a war amputee with a pegleg. His arms are simply not there period, no stump, I don't even know if the shoulder blades are there. There's nothing to strap a prosthetic on to, no easy means to control it. It is true that certain neuromuscular interface technology might be able to accomplish this, but this seems like it has been remarkably slow to develop, considering the encouraging preliminary results that people reported. Wnt (talk) 07:14, 30 July 2011 (UTC)

I've met lots of disabled people in my life. This guy is doing great, as are many of the others that I know. His electric wheelchair seems to give him most of the mobility he needs. I do have to say though that what was more stunning than his disability in that video was the god stuff. Unbelievable emphasis on that aspect. Hard to reconcile with this being the Science desk. HiLo48 (talk) 07:35, 30 July 2011 (UTC)

Well, this was a technical question, not a comment on the whole video. While the wheelchair gives him mobility, the problem is... what's he going to do when he gets there? He's obviously still very much dependent on external assistance for any task - and with the right technological development, he would no longer need to be. Wnt (talk) 14:20, 30 July 2011 (UTC)

Yes, and humans can be wonderfully ingenious in inventing devices to serve the needs of individuals like that. (And I emphasise the individual.) The guy seems pretty smart himself, apart from that god stuff. I just hope they're not expecting their god to do it all for them. HiLo48 (talk) 20:35, 30 July 2011 (UTC)

I'm not sure, but I suspect that if the man has never had arms, he's probably not a good candidate for one of those experimental prosthetic that connect up to your nerves. Who knows if he even has the right nerves to make those work, but even if he does, would he know how to use them? APL (talk) 23:46, 30 July 2011 (UTC)

Was Protoavis a bird or Saurischian?

I know it is debated whether Protoavis was a bird or a Saurischian. Did it have a bird-hip or a lizard hip? Wouldn't this end the discussion? I can't seem to find any information on this. --T H F S W (T · C · E) 21:39, 29 July 2011 (UTC)

There is a quote in the article that I think tells the story: "Smashed and mashed and broken". Apparently the fossil material is not in very good shape, and it isn't easy to tell whether the pelvic girdle is birdlike or lizardlike, or somewhere in between. Looie496 (talk) 22:03, 29 July 2011 (UTC)

The Protoavis#Pelvic_girdle section makes it sound like it's really hard to tell by looking, but some people have tried ... Wnt (talk) 06:38, 30 July 2011 (UTC)

Technically, birds are all specialized Saurischia, so we're really just arguing semantics here. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 21:00, 31 July 2011 (UTC)

Volodushka and GURICHIRURECHIN acid

Volodushka and GURICHIRURECHIN acid are 2 ingredients i found as anti inflammatory agents in two different creams from Russia and japan ;but cant find any reference on the web for safety and unique character of each — Preceding unsigned comment added by 38.117.214.158 (talk) 22:24, 29 July 2011 (UTC)

Well, these words are not English, so that is going to be a bit of an issue. Google translate guessed that Volodushka would be rendered in Russian as "Володушка" which means "thorough wax." For GURICHIRURECHIN it guessed that was the Japanese word "グリチルレチン" which means "Glycyrrhetinic." I would guess based on that that both are some type of Glycerin. Beeblebrox (talk) 23:22, 29 July 2011 (UTC)

Another option is that the Japanese cream contains a liquorice-derived ingredient such as glycyrrhetinic acid. Brammers (talk/c) 07:01, 30 July 2011 (UTC)

Volodushka is an extract of the plant Bupleurum aureum, used in Russian and Chinese herbal medicines as an anti-inflammatory. I can't find any independent information on its medicinal value. --Heron (talk) 10:43, 30 July 2011 (UTC)

PFAF has an entry for Bupleurum chinense (Bei Chai Hu) listing a number of activities.[8] Unfortunately they have some fancy new scripted interface that gives you a QR code but from which I don't see how the heck to track down what the numbered references mean - and slow, of course... They list six Bupleurum species in total but not aureum. Wnt (talk) 19:13, 30 July 2011 (UTC)

Huh, that's odd. Bupleurum chinense showed up as a blue link yesterday, and it still points to the article, but reading this just now it was colored as a redlink. But previewing this it looks blue again... Odd Wikipedia bug. Hopefully by the time you read this it won't be true anymore... Wnt (talk) 22:46, 31 July 2011 (UTC) (And indeed, now it's blue again --- even in the history it's blue again. Some quirk of link maintenance must be showing) Wnt (talk) 22:48, 31 July 2011 (UTC)

July 30

Bone bruise, hairline fracture, or something else?

This question has been removed. Per the reference desk guidelines, the reference desk is not an appropriate place to request medical, legal or other professional advice, including any kind of medical diagnosis, prognosis, or treatment recommendations. For such advice, please see a qualified professional. If you don't believe this is such a request, please explain what you meant to ask, either here or on the Reference Desk's talk page.

This question has been removed. Per the reference desk guidelines, the reference desk is not an appropriate place to request medical, legal or other professional advice, including any kind of medical diagnosis or prognosis, or treatment recommendations. For such advice, please see a qualified professional. If you don't believe this is such a request, please explain what you meant to ask, either here or on the Reference Desk's talk page. --~~~~

Sorry. APL (talk) 00:08, 30 July 2011 (UTC)

Just to go on the record here, I very heavily contest the fact that my question has been marked as a request for medical advice. The situation I am inquiring about occurred so long ago that I can't specifically remember when (probably 1-3 years ago), and the question requested information completely separate from advice (I've been around long enough that people should know by now I would be smarter than to ask for medical advice on Wikipedia)...it could have been answered with a simple link or explanation to the differences in symptoms between two conditions. In the interest of not going on an edit war I won't revert the deletion again (WP:BRD, if you will), but I strongly disagree with the question being considered a request for medical advice. Ks0stm ^(T•C•G) 01:11, 30 July 2011 (UTC)

I'd argue on your behalf, except ... I didn't know how to answer that question anyway. If it were easy to tell what happened by the difference in symptoms, there wouldn't be so many doctors sending people for X-rays. Wnt (talk) 07:05, 30 July 2011 (UTC)

Cloud phenomenon

Okay, I cave. I've watched several different videos of this phenomenon, so I'm fairly certain it's real, but I have absolutely no idea what's happening here or here. It seems like every time it shows up the person is behind the cloud from the sun, with the sun just below the lip of the top of the cloud, and the cloud has a diffuse, icy pileus around the top. Anyone care to speculate on what's causing these strange light "bouncing" phenomena? -RunningOnBrains^(talk) 00:58, 30 July 2011 (UTC)

I don't know, but if I had to guess: it looks like a source of bright light sweeps across a cirrus cloud (which may be the anvil of a cumulonimbus cloud). The bright light appears to shift, with different "fronts" of light moving across the cirrus cloud quite quickly. Assuming that the only source of bright light is the sun, and that the atmosphere above the cirrus cloud is pretty boring, the only possibility that I see is that the light is being reflected from below. As it seems pretty sunny out, it doesn't seem like it could be reflecting from a lake with seiches or something - rather, my guess is that it's being reflected at an angle by ice crystals, perhaps in the cirrus cloud, more likely in the cumulonimbus formation just below it. Presumably as the winds shift, or the temperature of the air changes, the light is reflected from a different point or refracted in a different direction, causing the rapidly changing lights.

There's a theorem in astronomy that no body can change brightness in a faster time than it takes light to cross it. I wonder if something similar applies to a situation like this involving the speed of sound. Since the patterns seem to change within 0.5 to 1 seconds, I would picture that the reflecting feature should be less than about 150 to 300 meters in size. But I don't know if that's really valid. Wnt (talk) 06:34, 30 July 2011 (UTC)

As Wnt suggests,its a form of Sun dog phenomena. The moving clouds are repeatedly occluding a patch of ice crystals in the higher parts. --Aspro (talk) 09:39, 30 July 2011 (UTC)

Bone tracheas

I was quite confused by the following passage:

One skeleton taken out of this part of the mound had the appearance of a very aged man; the point of the inferior maxillary was almost in two parts, while the trachea was bone all around. Quite a number showed indications of extreme age; seven or eight that I observed had bone tracheas.

The context is a railroad official overseeing the excavation of a Glacial Kame archaeological site in the 1850s. So what's a bone trachea? I put this into Google and didn't find anything useful; most of the results were lists of body parts that happened to have "trachea" immediately following "bone". Nyttend (talk) 01:15, 30 July 2011 (UTC)

Cartilage tends to turn to bone over time. While some structures normally remain cartilaginous for life, ossification of tracheal cartilage can be a sign of advanced age. Ossification of tracheal cartilage in aged humans μηδείς (talk) 01:35, 30 July 2011 (UTC)

Try "trachea ossification" on google. Dauto (talk) 01:45, 30 July 2011 (UTC)

You will come up with the same paper I did above when I googled the same words. μηδείς (talk) 01:52, 30 July 2011 (UTC)

I always assumed that cartilage in childhood would normally remain cartilage throughout life, aside from issues such as arthritis; thanks for the help. I've now cited the linked PubMed article in a new article here about the site that was being excavated, the Ridgeway Site. Nyttend (talk) 02:33, 30 July 2011 (UTC)

The history and use of coal balls

The title says it all, pretty much. Does anyone know about the history of coal balls, and what they can be used for? --Σ ^talk_contribs 01:36, 30 July 2011 (UTC)

The only reference I can find to anything called "coal balls" at Wikipedia is found at the disambiguation page Niggerhead which indicates they were deposits of Pyrite found in coal mines. I have no idea if this is the item you are looking for. --Jayron32 03:43, 30 July 2011 (UTC)

I did find another reference to them, at Permineralization they seem to be small carbonate balls that represent the fossilized remains of microscopic plants. --Jayron32 03:51, 30 July 2011 (UTC)

A third possibility is the black fungus known as Daldinia concentrica. --Jayron32 03:53, 30 July 2011 (UTC)

I need information about the second possibility, about fossilised remains of plants. Thanks. --Σ ^talk_contribs 04:03, 30 July 2011 (UTC)

How about the mixture of clay and coal dust which Marco Polo wrote of and is used as a fuel in China today?—eric 02:59, 31 July 2011 (UTC)

Clay + coal dust is called a pencil. --Jayron32 04:53, 31 July 2011 (UTC)

Sounds of Earth from the Voyager Golden Record: volcanoes, earthquake, whale song, tractor... ?

I came across this article: Contents of the Voyager Golden Record, and I found myself trying to recognize the different sounds listed in the "Sounds" section. There is also a list on the NASA website: http://voyager.jpl.nasa.gov/spacecraft/sounds.html You can hear these sounds here: http://www.youtube.com/watch?v=s-6CvmmcG0w

I have several questions:

• Does the sound of volcanoes really start at 00:43?
• Is it the sound of an earthquake we can hear around 01:05?
• The list on the NASA website doesn't mention "Whale song"; but is it that sound that starts at 04:57?
• According to the list, there are two sounds of tractor, one that starts at 07:32 and one another at 09:25. The first one doesn't really sound like a tractor to me, rather like a jackhammer. What do you think?
• The list mentions "Thunder" before "Mud pots" and "Wind" just thereafter, but I can't hear them. Is it an error? You can hear the sound of the wind at 05:27.

Also, would it be a good idea to rearrange the list and to add the timing, like in the "Greetings" section? Thank you! --Glups (talk) 04:05, 30 July 2011 (UTC)

The 7:32 tractor sounds like it has Caterpiller treads and no muffler. Edison (talk) 20:01, 30 July 2011 (UTC)

orbit and mass

Is the mass of a planet related in any way to its orbit? --DeeperQA (talk) 08:17, 30 July 2011 (UTC)

Absolutely. Please see our article on orbit: "Newton showed that, for a pair of bodies, the orbits' sizes are in inverse proportion to their masses, and that the bodies revolve about their common center of mass. Where one body is much more massive than the other, it is a convenient approximation to take the center of mass as coinciding with the center of the more massive body."--Shantavira|^{feed me} 12:17, 30 July 2011 (UTC)

How does that conflict with the fact that massive planets - Mars, Jupiter - are in the middle tier of the Solar System, but small planets are on its extremes? — Preceding unsigned comment added by

88.8.79.148 (talk) 13:16, 30 July 2011 (UTC)

Mars is not particularly massive. Dauto (talk) 14:05, 30 July 2011 (UTC)

You are right on that. I was thinking about Saturn. 88.8.79.148 (talk) 14:20, 30 July 2011 (UTC)

No Shantavira, that's completely wrong. Newton has not showed any such relationship which is not observed in practice either. Our specific solar system's history has lead to some patterns described by Csmiller bellow but exoplanets have been found that do not follow that pattern. Dauto (talk) 14:05, 30 July 2011 (UTC)

Huh? I am quoting our article. Maybe you could fix it if it's wrong.--Shantavira|^{feed me} 15:55, 30 July 2011 (UTC)

The quotation is correct. Your interpretation of it is wrong. That quotation simply mean that the size of the orbit of the moon around the earth is much bigger than the size of the orbit of the earth around the moon because the earth's mass is much bigger than the moon's mass. It does not mean that if the earth had a second moon, than the size of the orbit of that moon would have to correlate in any way with its mass. Dauto (talk) 18:54, 30 July 2011 (UTC)

I said nothing about the size of the orbit, just that there is a relation between orbit and mass.--Shantavira|^{feed me} 05:52, 31 July 2011 (UTC)

The question is clearly about the size of the orbit. what else would it be about? Inclination? right ascension? Dauto (talk) 20:28, 1 August 2011 (UTC)

See Formation and evolution of the Solar System#Formation of planets. Basically for Mercury to Mars, the Sun is hot enough to boil off most of the hydrogen from the planet. Further out the surface of the planetary core (which would been rocky or metally) would be cold enough for the captured hydrogen (and helium) to be captured - the thermal velocity of the gas is less than the surface escape velocity. In the trans-Neptunian area, there is not much hydrogen to be captured. CS Miller (talk) 13:30, 30 July 2011 (UTC)

It's not well understood at this time. Count Iblis (talk) 15:00, 30 July 2011 (UTC)

There are many satellites at altitude 35,786 km above the equator that have exactly 24 hours orbital period, see the article Geostationary orbit. Geostationary orbit is independent of the mass of the satellite. The orbital periods of planets about the Sun are similarly independent of their masses. Wikipedia has a long List of satellites in geosynchronous orbit that have a wide range of different masses. Cuddlyable3 (talk) 00:28, 31 July 2011 (UTC)

That is only true because the masses of satellites are much smaller than the mass of the earth. The relation between radius, orbital period and mass is Kepler's third law. Unfortunately, the article does not give the general form: M is actually the sum of the masses of the primary (earth) and secondary (satellite). See e.g. the fourth equation in the German article. The geostationary orbit for a more massive satellite is slightly higher than for a less massive satellite. In practice, of course, this mass dependence is buried among parturbations and in all likelihood not measurable.--Wrongfilter (talk) 08:46, 31 July 2011 (UTC)

Does anyone know what this plant is, please?

A plant grew in my garden, and I've no idea what it is. Or was, as it grew on a long stem and looked temptingly like a cat toy, so my kitten attacked it, and it is no more. Here are a couple of photos: The entire plant: http://www.flickr.com/photos/63456161@N07/5990829659/in/photostream Close up of the head: http://www.flickr.com/photos/63456161@N07/5990829243/in/photostream/ Thanks for any information!Snorgle (talk) 19:23, 30 July 2011 (UTC)

Allium canadense --Digrpat (talk) 20:11, 30 July 2011 (UTC)

Thanks - that looks right(although I'm in the UK I suppose it could have been introduced), and it did smell garlicky too. The wiki entry suggests that it's edible AND poisonous, which is confusing, though.Snorgle (talk) 20:26, 30 July 2011 (UTC)

maybe Allium vineale my 1st guess anyway--Digrpat (talk) 20:33, 30 July 2011 (UTC)

That looks EXACTLY like it, thanks!Snorgle (talk) 23:24, 30 July 2011 (UTC)

Funny Science Video Clips

Can anyone suggest funny science clips like the one here Thanks! Barbaricslav (talk) 20:23, 30 July 2011 (UTC)

Turboencabulator. Cuddlyable3 (talk) 00:02, 31 July 2011 (UTC)

Unintentionally funny, but hilarious to me. -RunningOnBrains^(talk) 01:03, 31 July 2011 (UTC)

The "Duck and Cover" routine is probably not as useless as a lot of people seem to think. Obviously if you're within a certain radius of the bomb, you're going to die regardless. The point of "duck and cover" is to save people who are further away from the blast.--Srleffler (talk) 04:39, 31 July 2011 (UTC)

I think the funny part is using a cartoon with a turtle and a jingle, instead of a serious discussion of thermonuclear war. I picture a series of these videos, where being raped and murdered is treated to a cartoon and jingle, then maybe having your school bus catch fire as everyone inside slowly burns to death. StuRat (talk) 04:44, 31 July 2011 (UTC)

I always figured that it was largely to protect you from structural damage - i.e. if the school roof collapses, it's probably a good idea to be under a desk. Sturdy buildings, even near the epicenter of an atomic blast, can survive [9], and may retain enough of their integrity to keep the people inside alive. A book that I recommend reading for those interested in first and second hand accounts of the explosion is John Hersey's Hiroshima. Several of the survivors detailed were within a mile of the bomb blast. Buddy432 (talk) 19:46, 31 July 2011 (UTC)

A human is a lot sturdier than a building. A steel-framed building will pretty much always collapse when it's subjected to 5 PSI (a miniscule force). A human can survive a lot more than that (5 PSI is roughly equivalent to being punched hard in the gut). Whoop whoop pull up ^{Bitching Betty | Averted crashes} 20:51, 31 July 2011 (UTC)

PSI is not a measure of force, it is a measure of pressure. Assuming your numbers are correct, you should consider what would happen if you were hit with the same force as a punch but over your entire body, just as the building is subjected to the force over it's entire cross-section. If you were standing in the open, you would probably be thrown backwards rather than crushed, but if you were standing against a wall, say, you could easily be crushed against it. How well buildings survive such forces depends a lot of how rigid they are. If they can't move, then they will break. If they can move (by swaying, primarily) then they'll survive in the same way you would if thrown backwards. --Tango (talk) 23:15, 31 July 2011 (UTC)

Thinking about force and cross section is also part of the logic behind "duck and cover". By curling up into a ball at ground level, even if you aren't under any kind of shelter, you reduce your cross-section to the blast. Better than nothing...--Srleffler (talk) 02:40, 1 August 2011 (UTC)

How about a bit of Police Squad!? [10] Also, not science-related, I'm afraid - but I was reminded of the late, great Stanley Unwin [11], and more recent Fry and Laurie [12]. Sorry...I'm sure everyone can think of their favourite 'funny clips'... but I couldn't resist mentioning those.  Chzz  ►  06:46, 1 August 2011 (UTC)

July 31

Cold fusion

Cold fusion is referred to as "bullshit" above, and the article seems to say as much. I thought that there were reputable scientists, like those at the the San Diego Navy SPAWAR lab, who continue to produce confirmatory results and have never wavered in their support for cold fusion (e.g. [13]) and some Italian outfit that claimed to have built commercial scale reactors in the past year.[14] What is the current status of that controversy? 99.39.4.220 (talk) 00:54, 31 July 2011 (UTC)

The 'Italian outfit' can be found here: Energy Catalyzer. Opinions on its validity are, shall we say, divided. AndyTheGrump (talk) 00:58, 31 July 2011 (UTC)

(edit conflict)Certainly not bullshit. Nothing approached with an open mind and a receptive scientific attitude should ever be labeled "bullshit". There is certainly no convincing evidence that it exists (nor known theoretical mechanism by which it COULD exist). But people trying weird science is how some of the greatest advances of mankind have been achieved. Anyone claiming to have "proof" of anything does not deserve your attention. There is only evidence in science, never "proof". And until there is more than occasional irreproduceable evidence of the phenomenon, I say that there is no reason to believe it exists.

That said, the SPAWAR results are intriguing, but I think that we need to think about horses before zebras, in that there is likely some other energy source for the miniscule amount of heat they are able to produce. And I can not find anything about an Italian commercial application, but I can tell you that scam artists have been selling cold fusion kits for years.-RunningOnBrains^(talk) 01:01, 31 July 2011 (UTC)

It is not bullshit to explore weird stuff in a scientific manner. Cold fusion should be researched as with anything else. It is bullshit to make definitive claims on the success of research when there are none. Let me reiterate: research = good, making up things = bullshit. Much of the problems with the cold fusion was too much bullshit, not enough good. --Jayron32 01:45, 31 July 2011 (UTC)

What he said ::points at Jayron:: -RunningOnBrains^(talk) 02:27, 31 July 2011 (UTC)

Strength of atomic bonds

Hello... I was trying to get an idea of the strength of bonds between atoms by imagining that a water molecule, for example, was blown up to a size where I could hold it in my hands and pull it apart. However, I'm not sure how I should scale the force. Should it scale with the cube of the molecule length? Anyway, doing the calculation properly, what would be the force required to pull apart a water molecule if it was, let's say, 10 cm long? What would be the force required to separate two water molecules of that size in liquid water (keeping the individual molecules intact)? (Ignore the question of whether you could actually grasp such a blown-up molecule, and other similar quibbles.) 86.179.2.163 (talk) 01:20, 31 July 2011 (UTC)

I can't think of a single principle that would allow you to chose the proper scaling factor and in the absence of a principle your question is not answerable. Dauto (talk) 01:45, 31 July 2011 (UTC)

(edit conflict)Well, unfortunately, I do have a quibble. If you scale the size you still have to figure out how to scale all the other properties, like mass and charge, and this may not be a trivial answer. The H-O bond strength is 460 Joules...note that this is an energy required to break the bond, not a force. This is because at the molecular level the force needed to break a bond is unimportant, it is the energy input needed to break the bond that is constant. For this reason the was that you scale mass and charge becomes important. I feel like someone else should be able to explain this better, but suffice to say it is not as simple an analogy to scale up bond-breaking as it might seem.-RunningOnBrains^(talk) 01:48, 31 July 2011 (UTC)

460 joules seems vastly too great a number? Did you miss off a factor of ten to the power minus something? Despite the objections, and despite not being able to work it out myself, I feel it ought to be possible to give a sensible answer. To put it another way, if I was shrunk down to the point where I could hold a water molecule in my hand, how hard would it be to pull it apart. It seems like a question that ought to have a sensible answer.... ! 86.179.2.163 (talk) —Preceding undated comment added 01:56, 31 July 2011 (UTC).

Actually, I was off in two ways. I was trying to say 460 kilojoules (110 kCal), but that's per mole, so take that number and divide by Avogadro's number to get the energy per bond. Sorry. Anyway, it is still a unit of energy, which is the crux of my argument. -RunningOnBrains^(talk) 02:19, 31 July 2011 (UTC)

OK, well, how would the force generated by my muscles decrease as I shrank? If I could pull 100 kg at full size, and then I was halved in size, could I pull 100/8 kg? 86.179.2.163 (talk) 02:07, 31 July 2011 (UTC)

Do an experiment. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 02:37, 31 July 2011 (UTC)

Silliness aside, your reasoning sounds correct. Various internet sources seem to claim that strength is connected proportional to muscle A) mass, B) volume, or C) cross-sectional area. Not sure which is correct, as no reliable source seems to weigh in on the matter as far as I can tell. -RunningOnBrains^(talk) 02:47, 31 July 2011 (UTC)

A and B seem pretty much the same, in this case, since the density of muscle is more or less a constant. C would also be the same, if we assume the length of the muscles being compared is the same. StuRat (talk) 18:29, 31 July 2011 (UTC)

OK, RunningOnBrains gave the OH bond energy, which I understand is the usual way of expressing bond strength, but what I would like to know is the force. For example, what force would be needed to pull a hydrogen atom off a water molecule? More specifically, I guess there would be a varying force as the atom was pulled away, so I would like to know the maximum force at any point during the separation (I'm not sure where that would occur). Does anyone have that information? Or just a ballpark figure that would be representative of a typical molecule would be great... 86.183.129.83 (talk) 21:55, 31 July 2011 (UTC)

As RunningOnBrains said, it doesn't make much sense to talk about force in this context. It's energy that matters. How that energy is delivered is irrelevant. --Tango (talk) 23:19, 31 July 2011 (UTC)

I don't understand why it doesn't make sense to talk about force. Could you not use force to pull two bonded atoms apart? Why is that force not (in principle) measurable? 86.183.129.83 (talk) 23:53, 31 July 2011 (UTC)

Energy is required to do work and work is required to break bonds. Force is important in that you may need a certain minimum amount of force to do work which may require that the minimum amount of force be applied over a minimum amount of time. --DeeperQA (talk) 00:11, 1 August 2011 (UTC)

I imagine two bonded atoms a bit like like ping-pong balls connected by a spring (albeit a spring that gets weaker at a great distance). If I could physically grasp the two nuclei and pull them apart, would it not require a (distance-dependent) force to do that, just like the ping-pong balls and spring? I do not understand why this force cannot be quantified, if that's what people are saying. Maybe I am fundamentally misunderstanding something. (To be clear, I am not looking for reasons why bond energy might be a more useful quantity, I just want to understand why the force that I am talking about is not, in principle at least, quantifiable, if that's the case). 86.183.129.83 (talk) 00:24, 1 August 2011 (UTC)

Could you not estimate the force by getting a crystal such as an hourglass-shaped piece of ice, calculating the number of water molecules in its smallest cross section, and then measuring how much force was required to pull (not bend or snap) it apart? 2.101.14.124 (talk) 11:08, 1 August 2011 (UTC)

Here is a table of rupture forces. The atoms in water are held together by covalent bonds, which appear to be on the order of 1000 piconewtons, while the hydrogen bonds between water molecules rupture at a few piconewtons. --Heron (talk) 18:30, 1 August 2011 (UTC)

Severed hands

If one's hand is sliced off, is he likely to bleed to death? Whoop whoop pull up ^{Bitching Betty | Averted crashes} 02:46, 31 July 2011 (UTC)

Why not? Cutting you wrists seem to be an effective mode of suicide. Plasmic Physics (talk) 03:07, 31 July 2011 (UTC)

Unreliable sources have claimed otherwise. Also i remember reading a statement (admittedly online) about cutting wrists hardly ever resulting in anything more than a scar (paraphrased near quote). Whoop whoop pull up ^{Bitching Betty | Averted crashes} 03:11, 31 July 2011 (UTC)

Cutting ones wrists often does result in a scar for a few reasons. Someone might find the person, call the local emergency services, and save the person. The person may just be trying to get attention and do it in front of someone who then calls. The person may not do it well enough, pass out, it clots, and they're found. Often the person doing the cutting doesn't do it well enough to actually exsanguinate themselves, passes out, wakes up later, cries, and goes on with their life. What do you expect, they're amateurs and probably don't know that much about what they're actually attempting. Dismas|^(talk) 03:37, 31 July 2011 (UTC)

So, considering all that, what would completely severing the hand do? Whoop whoop pull up ^{Bitching Betty | Averted crashes} 03:57, 31 July 2011 (UTC)

If no medical attention were given, and no attempt was made to staunch the flow of blood? Kill them. If drastic lifesaving measures were used, they may survive. --Jayron32 04:22, 31 July 2011 (UTC)

Agreed. The most immediate difference would be made by applying a tourniquet. StuRat (talk) 04:23, 31 July 2011 (UTC)

Really? What to Expect the Toddler Years claims that applying pressure to the wound is usually sufficient to staunch the flow of blood even in such extreme circumstances. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 04:32, 31 July 2011 (UTC)

That's what a tourniquet is, a means of applying pressure to an extremity, for the purpose of reducing the flow of blood. StuRat (talk) 06:04, 31 July 2011 (UTC)

As I understand it, there's a big distinction in practice. Usually a tourniquet doesn't apply pressure to the wound itself, but to the blood vessels upstream of the wound. Secondly, a tourniquet typically cuts off almost all blood flow to the extremity, as opposed to direct pressure to the wound itself which still allows blood flow to vessels not compressed (e.g. on the other side of the limb). "Use a tourniquet" is a much more drastic intervention than "apply pressure to the wound", and the two should not be treated as synonyms. -- 174.24.213.112 (talk) 18:03, 31 July 2011 (UTC)

In general, yes, but in the case of a severed hand, I can't see how you could "apply pressure to the wound". Does that mean you'd clamp a hand tightly over the end of the stub ? I can't see that working. Perhaps you could squeeze the arm tightly further up, though, which is precisely what a tourniquet would do. StuRat (talk) 18:24, 31 July 2011 (UTC)

I recently took a first aid course and they no longer teach tourniquets. They don't event teach the use of pressure points. Apparently, people tended to do more harm than good with them. Direct pressure and elevation are usually sufficient even in extreme cases. It's not difficult to apply direct pressure to the stump of an arm. If your hand is all you had available, then use it, but ideally you would put a large sterile dressing over it (perhaps using your hand to apply more pressure, since it would be difficult to tie a tight bandage in that location). If you don't have a dressing, you could take your shirt off and use that. In addition, you elevate the wound above the heart. That should be plenty to stop the bleeding. I have read that in cases of total traumatic amputation, the bleeding is actually quite small. If an artery is completely severed, it tends to contract, which slows the bleeding. --Tango (talk) 18:43, 31 July 2011 (UTC)

I even more recently took a first aid course as part of Scouting/Guiding. We talked about how tourniquets are no longer taught in more first aid courses, but also talked about the possibility (if you're letting the children take any sort of controlled risk, as we are supposed to) that you actually might need to, and that obviously we wouldn't use it just because someone was bleeding, but that if someone has lost a limb and/or is gushing blood so that a significant proportion is on the ground, and the ambulance is not here, your choice is basically tourniquet or dead child. If you let children use axes and saws, you can try to teach them safety and control the situation, but you also need to plan for the worst. It's all very well talking about the danger of cutting off circulation to flesh, but is someone is bleeding out and you can't stop it, they will die. So you try another way, and if it doesn't work and they are still bleeding catastrophically, you do what can save their life. We also talked about how the way we were taught to make a tourniquet as children ('as tight as possible') is the real problem, and that you should only tighten until the bleeding has just become slow enough to control, or just stopped if there's no other way to stop it. Catastrophic bleeding actually comes at the top of list of priorities for first aid, these days. You can't circulate oxygen around the body if there is no blood. 86.164.73.187 (talk) 20:35, 31 July 2011 (UTC)

Certainly, in a matter of life and death you do whatever you need to do to save the life. It's very unlikely that a tourniquet will ever actually be necessary, though. It only helps for bleeding limbs and try tend not to bleed that much. When people bleed out, it is usually from abdominal wounds. On my course they mentioned that when they had taught tourniquets, they taught people to release it every ten minutes for a few seconds to allow the limb to re-oxygenate. For anyone considering using a tourniquet, be aware that you could face legal action if you do it wrong and cause more harm than good, since it isn't a recommended part of first aid (so may not be covered by good Samaritan laws). --Tango (talk) 21:46, 31 July 2011 (UTC)

Why on earth would I let my children use this?] Whoop whoop pull up ^{Bitching Betty | Averted crashes} 21:40, 31 July 2011 (UTC)

I'm removed the giant image you posted here of an antique horseman's axe because it was distracting and completely irrelevant.

It's perfectly normals for children to be allowed to use modern wood-cutting axes and hatchets with varying degrees of supervision. The Boy Scouts do it all the time. That's ages 10 through 18(In USA). And I'm sure kids who grow up on farms or out in the woods also learn to use those tools at an early age. But that doesn't really have anything to do with the question. APL (talk) 01:32, 1 August 2011 (UTC)

Survival probably wouldn't depend on "drastic lifesaving measures". Some basic first aid would suffice. You're probably right, though, that left untreated it would be fatal.--Srleffler (talk) 04:47, 31 July 2011 (UTC)

Perhaps "immediate" would be a better term than "drastic". StuRat (talk) 06:05, 31 July 2011 (UTC)

Don't forget about cauterisation. Plasmic Physics (talk) 05:37, 31 July 2011 (UTC)

Now that really does seem "drastic", especially when done in the field with whatever hot object is handy and without any anesthetic. StuRat (talk) 15:45, 31 July 2011 (UTC)

OWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW! Whoop whoop pull up ^{Bitching Betty | Averted crashes} 15:57, 31 July 2011 (UTC)

Yes, do forget about cauterisation! It almost always does more harm than good. You would eliminate any chance of reattaching the hand (which is entirely possible with modern medical techniques - see microsurgery). Even if reattaching the hand wasn't going to be possible anyway, you would eliminate the chance of getting a clean stump without amputating more arm, which could make use of a prosthetic more difficult. There are also all the usual risks associated with severe burns, which can be life threatening. --Tango (talk) 18:43, 31 July 2011 (UTC)

It is extremely possible for a severed hand to develop some kind of infection which left untreated or the person has a weak immune system could possibly die from that. Bleeding to death is possible but its more likely to happen if both hands got severed which is hard for one person to do. --86.45.132.106 (talk) 20:41, 31 July 2011 (UTC)

I'm not sure I'd be that worried if the severed hand developed an infection - I'd be more worried about the parts still attached to the body... ;-) AndyTheGrump (talk) 02:26, 1 August 2011 (UTC)

Read about Aron Ralston. Bus stop (talk) 01:49, 1 August 2011 (UTC)

IR tech

Can an infrared or thermal imaging sensor detect a person buried under snow? 67.169.177.176 (talk) 03:59, 31 July 2011 (UTC)

It depends on the density of the snow and the sensitivity of the sensor. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 04:01, 31 July 2011 (UTC)

So a top-of-the-line IR sensor like those used by the military could do it easily, while a cheap $200 IR camera would be useless? Makes sense to me. BTW, am I right that you have an interest in aviation? 67.169.177.176 (talk) 04:11, 31 July 2011 (UTC)

Yup. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 04:30, 31 July 2011 (UTC)

Do you have an actual reference for this? Or are you completely making it up off the top of your head? APL (talk) 13:09, 31 July 2011 (UTC)

No need to cite the obvious... Whoop whoop pull up ^{Bitching Betty | Averted crashes} 16:33, 31 July 2011 (UTC)

If you said that about the specific claim on the encyclopaedia proper you would still find yourself challenged and the claim legitimately removed, and rightly so. Nil Einne (talk) 17:10, 31 July 2011 (UTC)

It would also depend on the depth of the snow and how long it has been in place. Right after an avalanche, the surface of the snow should be about the same temp everywhere, while, after some time, the snow near the body should be slightly warmer. StuRat (talk) 04:19, 31 July 2011 (UTC)

Unfortunately, by that time most of the victims would be dead. See Avalanche#Human survival and avalanche rescue. 67.169.177.176 (talk) 05:19, 31 July 2011 (UTC)

True, that's why I said "the body". So IR would likely only be useful for recovery of bodies, not for rescue. StuRat (talk) 05:59, 31 July 2011 (UTC)

Unless by some miracle someone is buried at a shallow depth (which means the snow warms faster) and/or has some kind of physiological traits that allow him/her to survive being buried without suffocating or freezing to death. (It seems there's always a case or two like that after any major building collapse {earthquake, 9/11, etc.}, and I've even read of one case where someone was dug up alive from an avalanche after being buried all day long.) Could be a good plot twist. 67.169.177.176 (talk) 08:25, 31 July 2011 (UTC)

You would need a passive microwave receiver to detect heat radiation from the body, at radio frequencies this travels through snow easily. These exist on some satellites, but I don't know if yo can get a hand held model. Graeme Bartlett (talk) 12:07, 31 July 2011 (UTC)

Thanks, but I'm looking for a helo-mounted model right now. (In any case, if you're looking for survivors on foot, then rescue dogs make a much better sensor.) 67.169.177.176 (talk) 01:32, 1 August 2011 (UTC)

Some burglar alarms contain them, so I don't see why not. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 12:49, 31 July 2011 (UTC)

Link please?

For me, Google is only turning up a couple of patents. But that's no help, since completely impossible things are often patented. APL (talk) 13:12, 31 July 2011 (UTC)

Here's a fun thread where this technology is discussed, one person, who claims to be a scientist studying exactly this says this about the equipment to find people with microwaves : "After decades of development, you currently need 2 skidoos, a sled, and 3 people to operate the proprietary equipment." APL (talk) 13:44, 31 July 2011 (UTC)

Perhaps we need to wait for the patents to expire so competition can kick in and provide a cheap, reliable, easy to use, and effective product. StuRat (talk) 15:19, 31 July 2011 (UTC)

Better yet, pay someone in the Patent office to revoke the patents. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 20:45, 31 July 2011 (UTC)

Oh, my, the things I would do with a portable terahertz imager and a powerful tunable terahertz maser. Find people under snow, look at the neighbors naked in their beds, reprogram their skin to make fetal keratin and blister up all over their bodies... so many possibilities, so little time. Someone has this equipment... Wnt (talk) 01:25, 1 August 2011 (UTC)

fart. Erm, flatulence

Exactly what is a fart composed of? Oh, that's obvious, it depends on what you eat/drink/do/say/whatever, but w What is the general base for a fart? Is it true that one can fart next to a lighter and get the fart fire cloud thingy? An editor since 10.28.2010. 05:37, 31 July 2011 (UTC)

a) It varies, of course, but Hydrogen, Methane, and 'air' (Nitrogen, Carbon dioxide, Oxygen)

b) Methane and Hydrogen burn explosively, so yes; it can also lead to burns, and a trip to hospital.

Wikipedia covers it, in a) Flatulence#Composition of flatus, b) Fart lighting.  Chzz  ►  05:50, 31 July 2011 (UTC)

Thank you. Chzz saves the day again --Since 10.28.2010 05:53, 31 July 2011 (UTC)

YouTube used to have videos of people lighting their farts. Don't know if there are still any around. Dismas|^(talk) 13:05, 31 July 2011 (UTC)

Adam Savage did it on Mythbusters (Episode 48 outtakes). — Michael J 06:45, 1 August 2011 (UTC)

Cymbal-eared aliens

A pair of clash cymbals in profile. The bell is in green and the straps are in red.

If a species of aliens had big ears shaped like cymbals, at the sides of their heads, what would their hearing be like? Megaconworlder (talk) 08:40, 31 July 2011 (UTC)

Out of this world?--78.148.142.14 (talk) 10:54, 31 July 2011 (UTC)

Not very good, cymbals are mostly flat except at the centre. Sound wouldn't be focused very well by cymbal shaped ears. Plasmic Physics (talk) 11:55, 31 July 2011 (UTC)

See pinna (anatomy).--Shantavira|^{feed me} 12:50, 31 July 2011 (UTC)

Cymbals are not mostly flat, by the way. They may lok that way from afar or on TV but they are actually almost never flat. It's much more obvious if you see from beneath. Beeblebrox (talk) 22:04, 31 July 2011 (UTC)

True, but probably still not a good shape for an ear. There's no focal point. APL (talk) 02:10, 1 August 2011 (UTC)

OK, conical. A cone is still flat along a generatrix, meaning there is still no focal point for the conical section. The central buldge however, does have a focal point. Essentially, the large conical outer section of the cymbal has no effect on sound focussing, and is superfluous. They are incorporated for a different purpose in the musical instrument, to improve tintinnabulation qualities. Plasmic Physics (talk) 14:07, 1 August 2011 (UTC)

NATO notation for color specification?

The Wikipedia page on the Union Flag has a section on its color specification. One of the specifications is in some “NATO” notation (e.g. “8305.99.130.4580” for the blue color of the flag). What color notation is that? --98.114.98.196 (talk) 13:07, 31 July 2011 (UTC)

NATO Stock Number - see the link. The wikilink in the article to the North Atlantic Treaty Organization was misleading; I'll change it.  Chzz  ►  16:04, 31 July 2011 (UTC)

HRT self-medication

I want to learn about HRT self-medication. Specifically, do people who do it buy the medication online or do they extract it from shop bought products? Please, spare me the "it's dangerous go see a doctor" speech; I'm not a transsexual and I've no plans to self-medicate. I'm just curious about how it's done. — Preceding unsigned comment added by 78.126.136.91 (talk) 14:55, 31 July 2011 (UTC)

Perseids, August 2011

Hi! I've been watching the Perseids for a few years now. The peak of this year's meteor shower is 13 August. However, full Moon also comes that night and will ruin the show. My question is: what night should be perfect for watching the Perseides if we consider both the peak of the shower and the moon phase (but not the weather)? 92.36.179.99 (talk) 16:17, 31 July 2011 (UTC)

Well, according to our Perseids article, the best viewing is in the pre-dawn hours, and to get darkness during that period you should watch a couple of days before the full moon. But if you don't want to be watching for meteors at 4 AM, you might prefer to watch a couple of days after the full moon, when it will be dark for a while after the sun sets. (I hope I got that right; I always have trouble with moon phases.) Looie496 (talk) 17:43, 31 July 2011 (UTC)

The very best time is still August 12 / 13, but after the moon sets. Because the moon is full there is only a small window when it will still be dark after the moon sets. At my location in the US, that gives a couple hours immediately before dawn. Dragons flight (talk) 17:51, 31 July 2011 (UTC)

Ciências - Química

Scientific American: A reportagem refere-se ao Sequestro de Carbono presente na atmosfera por meio de tubulações especiais, sendo devolvido ao subsolo em alta profundidade para ser reabsorvido, tornando-se útil novamente em um futuro distante, em forma de gás ou até mesmo de Petróleo(?). Qual seria a certeza científico-tecnológica da eficácia de tal procedimento? — Preceding unsigned comment added by 200.103.171.184 (talk • contribs)

The question refers to carbon sequestration. But we aren't going to answer in Spanish, and I don't see that point in an answer the OP won't be able to read. Looie496 (talk) 17:25, 31 July 2011 (UTC)

That's not Spanish. It's Portuguese! Portuguese happens to be my mother tongue, so you can take my word for it. For a second I didn't even realize that the question was not in English since I can read either of them effortlessly. He is asking if it is true that carbon dioxide re-inject underground might turn back into natural gas or oil in a distant future. Dauto (talk) 18:38, 31 July 2011 (UTC)

Well then, no. There's nothing to reduce or hydrogenate the carbon dioxide before it diffuses into rock fractures and sedimentation. 208.54.5.187 (talk) 20:36, 31 July 2011 (UTC)

Translation to Portuguese: Não porque não há como reduzir ou hidrogenar o dioxido de carbono que simplesmente se difundirá pelas rochas e sedimentos. Translated by Dauto (talk) 21:23, 31 July 2011 (UTC)

Agreed. Translation to Portuguese: Concordo. Dauto (talk) 21:23, 31 July 2011 (UTC)

Kepler’s 3rd law

Assuming the Kepler’s 3rd law is valid at the atomic level do the electron shells follow Kepler’s 3rd law? --DeeperQA (talk) 23:59, 31 July 2011 (UTC)

It sounds like you are using the old Dalton model of the electrons as little spheres which orbit the nucleus just like planets orbit the Sun. The modern conception is more that electrons exist as probability clouds, so classical orbital mechanics don't really apply, no. StuRat (talk) 00:06, 1 August 2011 (UTC)

No, I am aware that an electron cloud might even be a field but nevertheless what I am asking is whether the shells, in any regard, are related by two factors such as semimajor axis and period of orbit. --DeeperQA (talk) 00:21, 1 August 2011 (UTC)

The answer is no, electron "shells" have nothing at all to do with orbiting, even though the term "orbital" is used. Electrons don't "orbit" in the same way that a planet orbits a star; distance from the nucleus is described by a variation of the Rydberg formula, but this "distance" isn't the same thing as the "distance" a planet orbits from the sun. There is no correlation because its a completely different concept. If you want to get beyond a grade-school understanding of electrons, you need to let go, in every way, the idea that the electron is a little ball racing little circles around the nucleus. It works nothing like that. --Jayron32 01:19, 1 August 2011 (UTC)

I wouldn't say that. All the QM formulas started by working with classical concepts. The electron has an angular momentum, which matches where it is and "how fast it is orbiting"; it can't exceed the speed of light while orbiting as we discussed with end of the periodic table. It just isn't really a nice neat little ball, but a sort of wave of probability. Now looking up Kepler's third law, "The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit." Now the infamous Bohr model gives orbital radius (they're circular) proportional to the square of n; the velocity is proportional to the inverse of the square root of the radius (and thus 1/n); so the period (circumference / velocity) should be proportional to n cubed. That means that the radius : period is indeed square : cube, just like in Kepler's law. Bohr's model gives real results for hydrogen atoms, so it's not irrelevant. Now quantum mechanics and the Schroedinger equation involve more complex terms for interactions between charges, and end up resorting to numerical methods for solution, but the three-body problem isn't really so tractable even in orbital mechanics. Also note: Rydberg atoms (i.e. atoms that are almost but not quite ionized, with electrons orbiting a nucleus at a great distance) actually do have electrons moving in "Keplerian elliptical orbits", according to the article. Wnt (talk) 02:15, 1 August 2011 (UTC)

The five d orbitals in ψ² form, with a combination diagram showing how they fit together to fill space around an atomic nucleus.

In most cases Kepler's equations cannot be used to make predictions about the orbits of electrons. Excepting some special cases as mentioned above.

Electrons orbiting a nucleus...

• Cannot be described as solid particles.
• Do not orbit the nucleus in the sense of a planet orbiting the sun, but instead exist as standing waves.
• Are never in a single point location, although the probability of interacting with the electron at a single point can be found from the wave function of the electron.
• Jump between orbitals in a particle-like fashion. For example, if a single photon strikes the electrons, only a single electron changes states in response to the photon.
• Retain particle like-properties such as: each wave state has the same electrical charge as the electron particle. Each wave state has a single discrete spin (spin up or spin down).

"Despite the obvious analogy to planets revolving around the Sun, electrons cannot be described as solid particles. In addition, atomic orbitals do not closely resemble a planet's elliptical path in ordinary atoms. A more accurate analogy might be that of a large and often oddly-shaped "atmosphere" (the electron), distributed around a relatively tiny planet (the atomic nucleus). One difference is that some of an atom's electrons have zero angular momentum, so they cannot in any sense be thought of as moving "around" the nucleus, as a planet does. Other electrons do have varying amounts of angular momentum."

see Atomic orbital.

Electrons are odd ducks that are not ducks. - ArtifexMayhem (talk) 03:26, 1 August 2011 (UTC)

The atomic orbitals derive from the same Hamiltonian that classically gives you the Keplerian orbits, so some probabilistic variant of Kepler's laws must apply to them, but I'm not sure exactly how it works. The classical orbits and quantum orbitals are closely related.

That d-orbital image is terrible. The five individual orbitals are badly hand-drawn (compare this), and the "combination" orbital is complete nonsense. A combination of all orbitals of a given type should look like a sphere, if it looks like anything. I can't believe that image is being used in major mainspace articles after all these years. Surely there's something better on Commons. -- BenRG (talk) 08:00, 1 August 2011 (UTC)

August 1

Block erasure

Why can flash memory be read and written one cell at a time, but only erased in blocks? I've read the flash memory article, and it seems that erasure is just a matter of bringing the control gate low and the drain high, which doesn't seem any more complicated than programming the bit. --140.180.16.144 (talk) 00:19, 1 August 2011 (UTC)

It is a different mechanism. Imagine a flash memory made up of buckets of water. You can ask whether any particular bucket is full. You can fill any particular bucket. Or you can pull the "single" bit of string that opens the bottom of a whole block of buckets to erase the block. Obviously it could be done differently, but memory manufacturers have decided that the block erase method is a commercially satisfactory compromise between being unable to erase at all and being able to erase any particular cell. -- SGBailey (talk) 11:40, 1 August 2011 (UTC)

Disulfiram and fetal alcohol syndrome

I had an episode "Choice" going in the background, where a pregnant woman ends up being sentenced to a court-ordered alcohol treatment program to avoid fetal alcohol syndrome. I became curious whether the notoriously unpleasant combination of Antabuse (disulfiram) and alcohol would increase the risk of FAS, and found some references suggesting that acetaldehyde, which is what builds up when the drug is taken to interfere with alcohol degradation, does indeed have teratogenic effects,^[15][16] though one study found that disulfiram didn't make these worse.^[17] All these studies were quite old, and seemed to mark this as a question of some public health importance, yet I'm reading that disulfiram has remained "FDA pregnancy category C" with no information about whether it is harmful or not to pregnant mothers. How is it that this question has never officially been sorted out one way or the other? Wnt (talk) 01:21, 1 August 2011 (UTC)

Prob'ly 'cause it takes a long, long time to do clinical studies in humans. FWIW 67.169.177.176 (talk) 01:43, 1 August 2011 (UTC)

Well, you certainly can't do a proper clinical trial to look for teratogenicity in fetuses - but you can look retrospectively at what happens when the mother chose to take the drug vs. not, with certain pitfalls. Wnt (talk) 01:50, 1 August 2011 (UTC)

Insane to order her to go on antabuse when she could be incarcerated for nine months and given valium to control the withdrawal symptoms. Rather silly premise. μηδείς (talk) 02:00, 1 August 2011 (UTC)

Incarcerated on what charge? I don't think I saw the episode, but the brief description at the linked article doesn't mention any criminal act on her part. --Trovatore (talk) 08:19, 1 August 2011 (UTC)

Sorry - this wasn't really a question about the episode, which never specifies what sort of treatment would be given at all. It just got me wondering whether authorities, one place or another, might be causing fetal alcohol syndrome with their forceful efforts to prevent it. Wnt (talk) 17:11, 1 August 2011 (UTC)

popularizing chemistry

I feel that many natural science branches like biology and physics are more popularized than chemistry.Am I wrong?If so, why is chemistry less popularized? Is it hard or something?--Irrational number (talk) 01:26, 1 August 2011 (UTC)

I dunno -- as a chemist, I don't find it hard at all. Maybe it's just that there's not as much earth-shaking basic research (as opposed to the more mundane but more useful applied research)? 67.169.177.176 (talk) 01:37, 1 August 2011 (UTC)

I think that there's a lot more biology being publicly funded than chemistry, which I think of as being done much more by corporations. Public funds encourage researchers to talk up (if not hype) their research to the public, whereas proprietary research tends to be done in secret, and when discussed by company employees, tends to be disbelieved by a skeptical public. Wnt (talk) 01:41, 1 August 2011 (UTC)

Plus, there are negative stereotypes of chemistry being a "dirty" science (as opposed to biology, which is "natural" and therefore supposedly "green"). 67.169.177.176 (talk) 01:45, 1 August 2011 (UTC)

I would be quite surprised if there was any correlation with amount of public funding received and amount of popularization. The areas of popularization are fairly narrow (a handful of sub-questions of each field, even in physics and biology), whereas the areas of public funding are quite broad. Furthermore, it isn't the case that popularizing your particular discipline (say, physics) is going to result in increased public funding for that discipline, as generally speaking most public funding of science goes into a big NSF pot that is then doled out by the NSF administrators and reviewers, not Congress or "the public" to any degree (and let's thank goodness for that!). --Mr.98 (talk) 01:55, 1 August 2011 (UTC)

This is quite an esoteric question - no way to clearly say exactly which part fits in which branch, and so forth. And, it depends what timeframe you look at, what countries you look at, all the problems of cross-field-studies (is astrophysics chemistry? Molecular modelling? etc) Depending on how you choose to divvy up "The Sciences", you'd get vastly different results. A related article, which might serve as a starting point, is Natural science. Personally, I don't think it is related to difficulty; it could relate to trend/fashion, and could relate to the way subjects (for e.g. Degree-level) are constantly being subdivided. I bet there's a bit of Chemistry included in various Quantum mechanics courses, and in a cooking degree. Is a chef a chemist?  Chzz  ►  01:51, 1 August 2011 (UTC)

In the United States, physics started being really popularized initially after WWII, because of its association with wartime weapons. In more recent years its ability to tell stories about our origins (e.g. cosmology) kept it relevant in the popular mind, and the "mind-blowing" aspects of quantum and relativity make for rather heroic (if often misunderstood) narratives. Biology is mainly popularized via discussions of evolution and genetics, both of which are quite popular in that they again tell stories about our origins and our current selves. Genetics has been of popular interest in the US since the 1920s or so, in part because of its connection with eugenics and race and all that, which really touch pretty deep into major American preoccupations. As for chemistry, there just doesn't seem to be as much popular association. In the best of times it is associated with industry and development; in the worst of times, with all of the excesses and downsides of industry and development (pollution, DDT, whatever). The aspects of it that do pertain to origin stories or selfhood quickly become assimilated into other fields (e.g. cosmology, again). Chemistry does not appear to tell very heroic stories about humanity or its place in the universe, though there is no inherent reason it need not. --Mr.98 (talk) 01:52, 1 August 2011 (UTC)

Here in Australia we have a major political leader who has publicly declared twice in the last week that carbon dioxide is difficult to detect because it's invisible, tasteless, odourless and weightless. That he was able to say it twice without embarrassment shows the poor public situation chemistry is in. HiLo48 (talk) 01:58, 1 August 2011 (UTC)

Wait til he finds out about the insidious chemical, dihydrogen monoxide. :-) StuRat (talk) 02:31, 1 August 2011 (UTC)

Common name, "Copious water"; always labelled "use sparingly" ;-)  Chzz  ►  06:54, 1 August 2011 (UTC)

Simplistic answer: Because as far as the environmentalist, organic food and natural health "industries" (both the crackpot and nominally rational varieties thereof) are concerned, chemistry is the Great Satan!(tm). The major selling point for much of food and "natural" medicines and other products advertising is the claim that they "contain no chemicals" and the gullible uneducated public swallow it whole. The chemical industry has simply been totally and utterly crushed in the propaganda war for public consciousness - probably because they never even noticed there was a war on until after they had already lost it. Roger (talk) 11:29, 1 August 2011 (UTC)

DNA testing of cremains

On a past set of episodes of the show Dexter, the forensics people performed DNA testing on a very small amount of cremated remains and were able to compare its DNA with the DNA from some nearby saliva and determine the two people were related. Is it actually possible to perform any useful DNA analysis on ashes? To forestall a particularly useless type of response seen pretty often on the Reference Desk, I will note in advance: Yes, I am aware that teleplays are works of fiction, and that authors of fiction often write things that are not possible. Comet Tuttle (talk) 02:50, 1 August 2011 (UTC)

Only if the cremation was done improperly. When a murderer splashes gasoline on a body and lights a match, for example, lots of DNA will likely remain. StuRat (talk) 02:57, 1 August 2011 (UTC)

(edit conflict)Doing a google search, I have found private companies that will take your money to do it for you: Here is but one example. However, others debate that this is normally viable in a properly done cremation: This page says that it isn't possible; This page says that it may be possible if teeth survived the cremation process. Neither of those are what I would call scrupulously reliable, but the College of American Pathology at least has a name that sounds credible, and they say that under normal cremation conditions, there is no way to get DNA. Apparently DNA can survive a "few hundred degrees" for a short time; the reference notes the possibility of recovering DNA from building fires, but cremation conditions (in excess of 2000 degrees C for in excess of 2 hours) doesn't leave anything behind. --Jayron32 03:04, 1 August 2011 (UTC)

Great references - thanks, Jayron32! Comet Tuttle (talk) 16:30, 1 August 2011 (UTC)

energy solution

Suppose public land in each County could be set aside and populated with solar farms and energy storage devices to form a giant power grid sufficient to supply all of the electricity needs of the United States and that this could be done for substantially less cost than the 14 trillion dollar deficit. Is there any reason why this could not be done immediately? --DeeperQA (talk) 04:45, 1 August 2011 (UTC)

Sure, you want to clear all of the nature off of the little bits of greenspace we have left? Turning earth into Coruscant doesn't sound like all that great of an idea... --Jayron32 04:54, 1 August 2011 (UTC)

Besides all other reasons, it is a long term solution, in the short term, it would only make the deficit grow. Plasmic Physics (talk) 04:56, 1 August 2011 (UTC)

Sorry, I did not think it necessary to mention that I am looking for scientific rather than financial or contrived reasons. For instance their are plenty of ways to avoid using green space which produces a little be of oxygen and if you can get rid of the deficit budget and opt for a surplus budget then you can solve two problems with one action. Please try again. --DeeperQA (talk) 05:06, 1 August 2011 (UTC)

So, you've invented a magical world where considerations like money and the environment don't matter, and you're asking us to critique it? With infinite resources and no financial or environmental concerns, you could do anything. By your criteria, you could set up a power grid based on hamster wheels if you wanted. Your solar system could be built if you had literally no other concerns at all. Back here in the real world, these concerns are important... --Jayron32 05:15, 1 August 2011 (UTC)

No need to be sarcastic, you could just have said that you don't perseive any scientific barriers, and that all the possible barriers are economical and evironmental in nature. (or something along these lines) Plasmic Physics (talk) 06:13, 1 August 2011 (UTC)

No. What I am asking is that you consider the end results and whether the end results would be sufficient to overcome real world difficulties instead of artificial difficulties such as already mentioned. --DeeperQA (talk) 06:05, 1 August 2011 (UTC)

Okay, how about this... Instead of going to Mars how about constructing such a grid? Would not that be a better project? --DeeperQA (talk) 06:18, 1 August 2011 (UTC)

Better in terms of what? Plasmic Physics (talk) 06:22, 1 August 2011 (UTC)

You name it. --DeeperQA (talk) 06:35, 1 August 2011 (UTC)

...err, I will rule out one: dealing with the aftermath of a giant asteroid hitting the US and blocking the radiation from the Sun. --DeeperQA (talk) 06:38, 1 August 2011 (UTC)

What I mean is, how are you comparing going to Mars against constructing such a grid? I frankly don't know what you want us to tell you. Plasmic Physics (talk) 07:10, 1 August 2011 (UTC)

I can not explain my question further. It seems clear to me that solar offers a global solution to energy needs and that cost can be handled in many ways. That leaves only the question of whether the science and technology at this point in time is sufficient to begin such a project now rather than wait until the only place to live is in outer space. --DeeperQA (talk) 08:25, 1 August 2011 (UTC)

I think if you have all these trillions of dollars available, investing in nuclear fusion would be a more assured long-term solution to energy supply, though there would be a longer delay before the investment paid off. Dbfirs 08:13, 1 August 2011 (UTC)

Obviously you can not create a 14 trillion dollar deficit unless the resources are available to do so and Chernobyl and Fukushima are good reason to avoid conventional fission based nuclear perhaps except for Thorium based fission rectors. --DeeperQA (talk) 08:25, 1 August 2011 (UTC)

If, like you said resources is not an issue, then either a massive scale solar project and colonising space are both possible projects. But, I'm not such what colonising space has to do with the USA's deficit problem. Plasmic Physics (talk) 09:06, 1 August 2011 (UTC)

Except as a questionable expenditure probably nothing. --DeeperQA (talk) 09:10, 1 August 2011 (UTC)

If you're looking to save the US budget by cutting NASA...I got news for you bud: NASA is a drop in the bucket. Its entire yearly budget is less than the military spends on air conditioning. NASA has arguably contributed more scientific innovations than any other organization in the world. There are better things to cut than scientific progress and research that is constantly bettering ALL our lives. How about we cut out some "fraud, waste and abuse"?-RunningOnBrains^(talk) 16:10, 1 August 2011 (UTC)

However, with electricity too cheap to measure a surplus budget could follow and forever be maintained in absence of perhaps anything except wise Chinese leader. --DeeperQA (talk) 09:13, 1 August 2011 (UTC)

That would be highly optimistic, even if you could do it for free like you said. Plasmic Physics (talk) 10:17, 1 August 2011 (UTC)

What does the US national debt have to do with it? The US government doesn't pay for people's energy. People pay for it themselves. In fact, the government gets a lot of revenue from taxes on energy. --Tango (talk) 11:42, 1 August 2011 (UTC)

The national debt is in the way. --DeeperQA (talk) 16:00, 1 August 2011 (UTC)

I just did a back-of-the-envelope calculation and came up with a cost of about 10 trillion dollars for enough solar panels to provide all the US's electricity, at current prices. (Don't take that number too seriously, though.) The reason it could not be done immediately is that at current efficiencies, it would require at least 10,000 square kilometers of solar panels, which could not be constructed in a short time. Looie496 (talk) 16:09, 1 August 2011 (UTC)

Current solar technology is crap. They only convert a small portion of the sunlight to electricity, steadily decrease in efficiency, must be cleaned of dust regularly, have no ability to store the electricity until needed, cost too much, must be turned constantly to face the Sun, etc. Improving the technology is the first step required. In the meantime, there are other energy sources which are ready to be built now, such as nuclear reactors built in safe places, like underground in unpopulated areas, rather than above ground, in heavily populated areas, right by active fault lines. With a high enough level of incompetence, any energy source can be made dangerous. StuRat (talk) 16:23, 1 August 2011 (UTC)

Solar thermal energy is not so terrible as all that, but yes, there's a capital cost. Wnt (talk) 17:04, 1 August 2011 (UTC)

better fit?

Does Kepler's 3rd Law of Planetary Motion find a better fit if it is changed from p^2 = a^3 to p^2 = a^pi(3.141593...)? --DeeperQA (talk) 09:55, 1 August 2011 (UTC)

If it did, wouldn't the be stated as such? Plasmic Physics (talk) 10:21, 1 August 2011 (UTC)

Kepler's 3rd Law is already a perfect fit (under Newtonian gravity and mechanics). It follows by a pretty simply mathematical derivation from F=GMm/r² and F=ma. If you want to allow for relativity then just changing the power isn't going to help at all. --Tango (talk) 11:45, 1 August 2011 (UTC)

No, of course it doesn't. The question is what makes you think it should or could? Dauto (talk) 13:02, 1 August 2011 (UTC)

I was thinking only about planetary orbit approximations and not about mathematical derivatives. I see it: 2*G*M*m/r^3 from G*M*m/r^2. Thanks. --DeeperQA (talk) 14:50, 1 August 2011 (UTC)

You should look into the modern derivation of the law - I was just talking about something like it with electrons. While Kepler's third law might once have been determined by observation, we now know that the radius of an orbit is proportional to the square of the angular momentum of the object, and the length of time it takes to complete that orbit (the orbital period) is proportional to the cube. It's not some arbitrary ratio we can just change or adjust; each of these things is the necessary mathematical consequence of other physical laws. Wnt (talk) 17:07, 1 August 2011 (UTC)

Statistics on Human Penis Size

Most of the charts I've seen look at stats for length or girth by themselves, I was wondering if there was any availible stats on both together. For example, what percentage of men have 6 inches length and 4 inches circumference, etc. 209.252.235.206 (talk) 10:32, 1 August 2011 (UTC)

What is an airlift system

Apparently fish are moved up the Haneji Dam using an airlift rather than a fish ladder. I've seen and understand a fish ladder. What is how does an airlift work? Is it an Airlift pump? If so, don't the bubbles harm the fish? -- SGBailey (talk) 11:33, 1 August 2011 (UTC)

I think "air lift" may be an artefact of the dam's page's Janglish (which also calls a fish ladder a "stared-fish ways") rather than a correct technical term. It may simply be some kind of pumped siphon system; this company has a bunch of fish-sucking equipment including a siphon fish ladder. I can't find specific information about what's deployed at Haneji. -- Finlay McWalter ☻ Talk 13:47, 1 August 2011 (UTC)

Current Control vs. Voltage control

Hello. I am currently reading up on cochlear implants, but had little luck in finding different control mechanisms. What are some advantages of current control vs voltage control (for cochlear implants specifically, but also in general) ?

Many thanks. 114.77.39.141 (talk) 11:53, 1 August 2011 (UTC)

This paper gives some of the answers. --Heron (talk) 17:33, 1 August 2011 (UTC)

Resurecting extinct species

Could species like the saber-toothed tiger or the mastodon be resurrected? There are some similar species which could get a genetically modified fetus contained the genome of them.Quest09 (talk) 12:15, 1 August 2011 (UTC)

There has been some talk of cloning up a moa (brief mention) and the Pleistocene Park guy wants a woolly mammoth. Right now we can clone mammals from a living cell: cloning up an extinct animal presents two major additional problems - firstly is getting a viable genome from something that has been dead for hundreds or thousands of years (that's surely easier for recently extinct things like the dodo and the thylacine than for mammoths, never mind dinosaurs), and secondly getting that genome into an egg and getting a clone to take from it. -- Finlay McWalter ☻ Talk 13:19, 1 August 2011 (UTC)

Mammoths have the advantages of being recently extinct as well as having lived in cold areas. Therefore, intact flesh of a mammoth may be found in the Siberian permafrost. However, DNA may still be found in bones and teeth of animals only a few thousand years old, provided they were properly preserved. This usually means they were encased in rock, before decomposition could work it's way into the interior of the bones and teeth.

Also note that finding a surrogate mother can be tricky, for mammals larger than any living today. Perhaps a mammoth could be placed in an African elephant, or a saber-toothed tiger in a Siberian tiger, but a c-section would be needed before the offspring became too large, with "premie" medical care performed after that. Birds are easier, as you only need an incubator for the eggs. You'd just have to guess at the ideal temperature, though. StuRat (talk) 16:02, 1 August 2011 (UTC)

Yes: part of the problem of using a surrogate mother of another species is that there is a great deal of interaction between the physiologies of mother and festus during gestation, so by virtue of their being different species, mismatches fatal to a successful gestation are likely, and even if the fetus is successfully born, it likely won't have developed in quite the same way as if it had been gestated in a mother of its own species. Incidentally, the loose term Sabre-toothed tiger covers several families of extinct mammals, none of which were anywhere near as closely related to the modern Tigers as, say, modern Lions. Similarly, Mastodons were not even in the same family as modern Elephants, and Mammoths were in the same family but not either of the same genera, so again the relationships are less close (though genetic closeness is not completely correlated with the "distance" of these taxonomic ranks), and the barriers likely to be greater, than is popularly supposed. {The poster formerly known as 87.81.230.195} 90.201.110.81 (talk) 19:50, 1 August 2011 (UTC)

Leptinella/Cotula

Hi there,

I am a very keen gardener from Newcastle, NSW Australia. I have no botany training at all, but I am interested in plants (Australian natives in particular). I bought a plant called Cotula purpusilla and I have been trying to sort out whether it is native to Australia or not. On the Wiki pages for Cotula and for Leptinella the information is a bit confusing as to which plants are called what and why there has been a change in the names and whether or not the changes have been accepted or not. And I still don't know whether my plant is native to Australia or not!

Don't get me wrong - I love Wiki! I guess it is just frustrating when the information given seems a bit muddled (in regard to the names). I suppose the other thing that would be really helpful on the plant info. pages would be to ensure that plant's country/state of origin as well as natural habitat is included.

Thanks so much for your time and effort, Fmcrowe (talk) 12:17, 1 August 2011 (UTC)

This page and others (note the correct spelling of perpusilla) indicate that the plant is native to New Zealand. This page says that the binomial name is a synonym of Leptinella pusilla. When taxonomists try to split or combine taxa, the results are often confusing. Deor (talk) 12:48, 1 August 2011 (UTC)

Weedicides

How does a weedicide know which is the required plant and which is the useless, unwanted plant? I asked this to my biology teacher but she too couldn't answer me. ID: (email removed) Name: Divesh Paryani — Preceding unsigned comment added by 41.58.128.95 (talk) 14:42, 1 August 2011 (UTC)

It doesn't. Many weedkillers kill all green plants, but common selective weedkillers tend to have little effect on plants of the grass family. Some crops are genetically modified to be resistant to general weedkillers such as glyphosate. The article on Herbicide might be of some interest, but it doesn't explain the biochemistry of resistance. Dbfirs 15:46, 1 August 2011 (UTC)

(ec) To answer your question, the herbicide doesn't "know". Rather, many herbicides (known as "selective herbicides") are specifically engineered to be ineffective against some desirable plants, or the desirable plants are themselves engineered to be resistant to particular herbicides. We note that glyphosate, sold as "RoundUp", was conceived as a non-selective herbicide (that is, it killed all plants), but that its popularity led to the development of glyphosate-resistant plants such that it can now operate as a selective herbicide. Note also that selective herbicides require specific intentional pairings of appropriate crops and herbicides; one cannot simply use a weedkiller at will with the expectation that it won't harm everything in sight. — Lomn 15:50, 1 August 2011 (UTC)

I've removed your email address; as you can see, answers will be posted here. I found a couple of articles, one here and also one here that might be useful. --some jerk on the Internet (talk) 16:34, 1 August 2011 (UTC)

Blushing

Hello. My name is Ian, I am vacationing right now in my mother's home city of Moscow and everyone is noticeably lighter here than back in the States, hence this question popping into my head. Because of my descent (mixed Russian-Finnish), I have a very light complexion, and furthermore I blush easily and to the smallest things; even more so, I've noticed, than even other Russians. A problem I have at home in the States is that when I blush it is more noticeable to others and it is often misinterpreted in social situations by my darker American companions. I know blushing is for the most part an unconscious action but is there anything I can do to reduce the frequency or exercise some control over it? My girlfriend advised me to get a tan but that didn't go so well-- apparently I don't tan, I just burn. Thanks in advance, and a happy summer to all! --Ian — Preceding unsigned comment added by 93.94.234.152 (talk) 17:10, 1 August 2011 (UTC)

Blushing is a signal of shame, and so being ashamed of blushing will only make you blush more. So don't be ashamed of it! Be proud of your blushes! Nobody except you really cares anyway. Looie496 (talk) 17:33, 1 August 2011 (UTC)

Wikipedia has an article about Blushing that describes what is known about its causes and possible treatments. You may take comfort (?) in the fact that no animal can blush, only humans do it. Animals don't have anything to blush about. Cuddlyable3 (talk) 17:39, 1 August 2011 (UTC)

"Man is the only animal which blushes ... or needs to." - Mark Twain StuRat (talk) 17:44, 1 August 2011 (UTC)

Well, make-up would do the trick, but you might find that objectionable (perhaps you could paint your face in your favorite team's colors, at sports events). There's also the "spray on tan" chemicals, although I wouldn't recommend them, personally. StuRat (talk) 17:46, 1 August 2011 (UTC)

Certainly a light foundation, as in the sort of skin-coloured make up you apply over your whole face, would reduce how noticeable the blushes were. This is, after all, why women add blusher on top of foundation. While you might find it objectionable, if you're doing it right, with a carefully chosen 'light' foundation or tinted moisturiser, chosen to match your facial skin (not the skin on your hand) and lightly and evenly applied, will be invisible to observers and still mask the blushing (as well as giving a smoother appearance to your complexion). It would, however, be cheaper and more wholesome to come to terms with your blushing and 'own' it as a personal attribute: "I am someone who clearly signals my moods and reactions, rather than disguising them". 86.163.1.126 (talk) 19:07, 1 August 2011 (UTC)

aspirin

Is aspirin an NSAID? — Preceding unsigned comment added by 99.70.40.100 (talk) 17:28, 1 August 2011 (UTC)

Yes, as our aspirin article states in its lead. Looie496 (talk) 17:30, 1 August 2011 (UTC)

(Keep in mind the `N' stands for NON, and the abbreviation NSAID is used to describe things in terms of what they are not. To paraphrase Ulam, saying Aspirin is an NSAID is like referring to the bulk of zoology as the study of non-elephant animals.) SemanticMantis (talk) 18:17, 1 August 2011 (UTC)

Instantaneous force

Hi, I'm designing a small plane; I'm working on the landing gear specifically. Suppose my plane is descending at a rate of 30 m/s at an angle of 45 degrees; What is the instantaneous force acting parallel to the ground, the moment the plane touches the ground? (Ask me if you need any extra data). 117.192.212.48 (talk) 18:00, 1 August 2011 (UTC)

I hope you're not designing a real plane, if you think that's a meaningful question. Looie496 (talk) 18:09, 1 August 2011 (UTC)

Planes don't usually land with a 45 degree glide slope but if yours does, its horizontal velocity is 30 m/s. The horizontal component of the instantaneous force on the landing wheels is whatever causes them to skid. Cuddlyable3 (talk) 18:19, 1 August 2011 (UTC)

I know; the descent angle is way too large. I mean to ask this as a simple physics question. I mentioned 45 degrees because the calculations will be easier. 117.192.212.48 (talk) 18:22, 1 August 2011 (UTC)

i want to know the instantaneous force at the time of impact. 117.192.212.48 (talk) 18:25, 1 August 2011 (UTC)

If your landing gear is rigid it will break. You cannot have instant deceleration of either the vertical or horizontal components of the plane's speed. Cuddlyable3 (talk) 18:28, 1 August 2011 (UTC)

We would need to know the mass of the plane (or the weight, from which the mass may be derived). The mass and radius of the wheels is also important, since they presumably will need to be accelerated from no rotation. I agree with the above comments, that descending at 45 degrees at 30 m/s will result in a crater. StuRat (talk) 18:41, 1 August 2011 (UTC)

Forgetting about the 45 degree angle that others pointed out isn't realistic, and assuming that the mass of the wheels are negligible compared to the mass of the plane, its clear without having to do any actual calculation that the instantaneous force acting parallel to the ground is negligible. Dauto (talk) 19:34, 1 August 2011 (UTC)

Yes, the horizontal force acts only to accelerate the wheels from initial skidding to rolling speed. Unless the wheels have a large moment of inertia, the force will be small compared with the braking force subsequently applied. To calculate the average force, you need to know the radius and moment of inertia of the wheels, the horizontal ground-speed at touchdown, and the skid time or distance. Once the wheels are up to speed, the only horizontal force is from friction in the bearings (and air resistance on the plane). Of course, if the brakes are already on as the plane touches down, rubber will be torn from the tyres by the greater friction force. Dbfirs 20:11, 1 August 2011 (UTC)

A simpler question contains the same basic issue: "Two blocks collide at 1 m/s. What is the instantaneous force between them at the moment of collision?" The answer must be that it depends on the mass of the blocks, Young's modulus, etc. The nearest parts of the blocks inevitably must match speeds first, and then transmit this force outward, in quite a complex way. The wheels of a plane add the additional variable that the force of friction is limited and they may slide over the landing strip as they first touch. Wnt (talk) 20:30, 1 August 2011 (UTC)

I have some Astronomy Questions:

1. Is it true the clouds of Venus are mainly composed of sulfur dioxide and sulfuric acid?

2. Is it also true Jupiter is also notable for its turbulent weather (e.g. huge storms, lightning, etc?

Thanks!

Neptunekh2 (talk) 20:27, 1 August 2011 (UTC)

I think the articles you linked cover those pretty well, and if not Atmosphere of Venus and Atmosphere of Jupiter should.

Control-F or Apple-F ("Find" in your browser) are your friends. ;) Wnt (talk) 20:34, 1 August 2011 (UTC)