Wikipedia:Reference desk/Archives/Science/2006 November 13

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1 November 13

[edit] November 13

[edit] One thing in two places at once.

I recently saw what the bleep do we know and found it quite disappointing, but it all made sense once I read about who it was produced and directed by. Some of it was entertaining I suppose, but one thing in particular caught my interest. In it one of the 'experts' claims that somewhere in a lab someone has created a something which exists in two places at once, a laser or something, which seems insignificant, but it IS actually the SAME thing in two places at ONCE. My question, is this true and if so what's it called, apologies if this has been asked a million times but I'm not even sure what to google or where to start looking. Vespine 00:18, 13 November 2006 (UTC)

Check out quantum teleportation Adambrowne666 00:55, 13 November 2006 (UTC)

Also, wave particle duality tells us that things we think of as particles are actually "wave packets", with a location described by a "probability function". In other words, these particles exist in many locations at once, in fact, every possible location at once (although they become more localized when observed, which is truly bizarre). StuRat 04:35, 13 November 2006 (UTC)

on the "what the bleep" thing, you might find Quantum mysticism interesting. Adambrowne666 06:42, 13 November 2006 (UTC)

Bilocation is an interesting read, although you may be in two minds about it. JackofOz 23:37, 13 November 2006 (UTC)

Yeah but bifurcation is even more painful!--Light current 23:39, 13 November 2006 (UTC)

The part in the movie was referring to wave particle duality and Young's double-slit experiment. X [Mac Davis] (DESK|How's my driving?) 17:01, 14 November 2006 (UTC)

No no, there is a guy on the show that says they have a box in a lab and it just looks like it has two things in it, but it is actually the same thing, it's in two places at the same time. He literally said you can go up and look at it with your own eyes. Like it's not just some split second thing that they did in a cyclotron that only a scientist can interpret by looking at a screen full of data. Anyway, reading all the articles above, sounds like BS to me. Vespine 04:18, 15 November 2006 (UTC)

[edit] Dinosaurs and Oil

Some friends and I are having some disagreement about where oil comes from. I learned when I was in Jr. High School that Oil came from Dinosaurs and other Prehistoric creatures that decomposed over the millions of years. I know that is a simple statement for a very broad subject that I found trying to get a simple answer out of over one hour of reading through much of the information that you have. I found it all very interesting but not simple enough to convience my friends. Then I may be wrong for all these 60 some years since I heard that in a class.

I would appreciate the answer, to satisfy all our curiosity, Jack Schram (e-mail removed)

See fossil fuel. --Ginkgo100 ^{talk · e@} 01:08, 13 November 2006 (UTC)

You ought to have a look at the articles you link to. That article doesn't have anything on where oil comes from beyond "formed from decayed plants and animals". A better explanation is at Petroleum#Biogenic_theory: oil is formed from the preserved remains of prehistoric zooplankton and algae which have been settled to the sea bottom in large quantities under anoxic conditions (no dinosaurs mentioned). And the reader may also be interested in Coal#Origin_of_coal, which is slightly more likely to have some dinosaur in it. —Pengo ^{talk · contribs} 01:34, 13 November 2006 (UTC)

I did look at the article before I linked to it. The sentence you quoted answered the question, although I admit there is not a lot of detail there. --Ginkgo100 ^{talk · e@} 05:48, 13 November 2006 (UTC)

The "dinosaurs got turned into oil" thing is a quote from the movie Airplane!. Inexplicably, it's not on our voluminous wikiquote page devoted to that film. I believe the next item in that brief history of the world was "And then the Arabs came!". Matt Deres 17:52, 15 November 2006 (UTC)

[edit] How do you pronounce the name of the sirtuin family of genes?

Thanks, anon.

You probably wouldn't go very wrong with "sir-two", but that's just a guess. Dar-Ap e 03:55, 13 November 2006 (UTC)

I'm not completely certain, but it could be like 'certain' 8-)--Light current 04:05, 13 November 2006 (UTC)

Would it be "sir-chewin"? -- T H L 23:03, 13 November 2006 (UTC)

The article is crappy, not bothering to explain many of the terms involved. It's not even clear to me whether it's SIRT2 or Sir2 (maybe they're different things, but if so, that too is far from clear). The term "sirtuin" seems to have been created as a name for the group of genes. That would suggest it is pronounced "Sir-two-in". JackofOz 23:46, 13 November 2006 (UTC)

"Sir-two-in" is how I've heard it pronounced at scientific talks. Ignoramibus 02:21, 14 November 2006 (UTC)

"Sir-two-in" if you speak American English, "Sir-tyoo-in" if you speak the vernacular. Rockpocket 06:43, 14 November 2006 (UTC)

[edit] Does this make sense?

This is a strange idea I'm playing with.

There's a room of almost infinite size. A cable has been suspended from the ceiling, hung straight down. The cable is so long (a length so close to infinite that any but the most pedantic mathematicians would call it so) that it cannot support its own weight.

So the cable breaks not far from the top just a few seconds after it's hung. But nevertheless, the engineers who made the cable know it's perfectly safe to hang a cablecar from the bottom end of it, because the effect of the break, travelling down the cable in a wave (at the speed of sound?), won't be felt in the cablecar for a period of time so long that any but the most pedantic mathematicians would call it so.

There you go: just as a thought experiment, does this work?

Thanks for any replies. Adambrowne666 00:54, 13 November 2006 (UTC)

sure it works, except for the fact that there is no such thing as "close to infinite"; it's either finite or infinite, there is no "close". Anyway, a finite cable that breaks won't be noticed at the other end for a finite time. Whether that amount of finite time is significant to you, depends on your engineering standards. --GangofOne 01:02, 13 November 2006 (UTC)

Yes, as long as you're prepared to have the cablecar drop and break whenever the "signal" from the top of the rope reaches it. --Bowlhover 01:06, 13 November 2006 (UTC)

Beauty, that's what I wanted. Yes, Gang, you're right, of course, there's no such thing as close to infinite, but I'm fudging the notion of infinity for a sci fi thing I'm writing. Thanks, both of you. Adambrowne666 01:10, 13 November 2006 (UTC)

The "top" of the "infinite" rope would not have much gravitational pull from the Earth, as it's so far up. So, if it can't support its own weight, it's not the top of the rope that would be struggling so much as the "bottom" or middle, or whereever gravity kicks in. —Pengo ^{talk · contribs} 01:44, 13 November 2006 (UTC)

That's what I was thinking, the gravity thing. Also, could a rope of almost infinite length have its own gravity? or is its 3 dimensional mass never 'dense' enough? Vespine 02:04, 13 November 2006 (UTC)

Yes, gravity - didn't think of that - another excellent point which I will also have to wilfully ignore in the thing I'm writing. Adambrowne666 02:12, 13 November 2006 (UTC)

That's no doubt why it's called science "fiction". :) JackofOz 03:29, 13 November 2006 (UTC)

Pengo & Vespine: the top of the rope will always experience more tension than the middle or the bottom. Yes, Earth's gravity is not very strong at the top. But the top of the rope will have to bear to weight of all the rope below it, and the lower you go, the stronger gravity gets. --Bowlhover 05:28, 13 November 2006 (UTC)

Try reducing the problem to practical (even if impractical) case. If you posited say a 100 km or 1000 km cable of a given size, say 4cm woven steel, then what length of it suspended from space to Earth would exceed the tensile strength of the cable? How does the answer differ with cable diameter, that is, can a thinner or thicker cable support a greater length before it breaks of its own weight? Then when it breaks at the top, what is the propagation speed, i.e. how quickly does the bottom end respond to the break and drop the cable car? Per the Mythbusters experiment with breaking steel cables to see if the cable slap would slice a pig in half, would the stored energy in the stretched cable come snapping down the cable and hit the end like a rubber band smacking a fly? Edison 17:30, 13 November 2006 (UTC)

The break wouldnt travel as a wave, as it is the weight of the bottom that is the force that breaks the cable' so as soon as it was unsupported it would fall. Philc _T^E_C^I 19:22, 13 November 2006 (UTC)

Not possible. The information that the cable has broken cannot travel faster than the speed of light. The cable break will infact propigate as a wave, per Linear elasticity (WARNING:MATH). JBKramer 19:26, 13 November 2006 (UTC)

(Ignoring gravity differences) the car would be in free-fall anyway since it would be accumulating slack from above as the cable stretches (the propagation speed being much faster than the falling speed). I think.

[edit] Academic Equivalence of a UK Pilots License

What is the academic equivalence of a UK issued Airline Transport Pilots License ATPL(H). Any references will be much appreciated.—Preceding unsigned comment added by 86.141.223.90 (talk • contribs)

Perhaps I don't understand the question, but what makes you think there is such a thing? It's like asking about the academic equivalent of a driver's licence. Do you mean a degree in aeronautics? Or are you asking what academic qualifications airline pilots need?--Shantavira 09:29, 13 November 2006 (UTC)

[edit] Bioenergetics - Cellular energy expended on nucleic acid production?

I want to find information estimating the energy a cell expends producing different nucleic acid forms.

I am interested in: 1. Specific cell lines and a general comparison of Eukaryote, Archerotes, and Bacteria. 2. Different time frames from cycle specific to overall. 3. A comparison of DNA, ncRNA, rRNA, mRNA, etc. 4. Any insights or sources on methods to answer the above.

It seems to me these estimates would give an excellent characterization of the relative influence of various forms of nucleic acid (esp. non coding RNA vs mRNA) on phenoype and evolution.

Ben Haley --<email removed to prevent spam>--

I'm guessing you'd have to either find a study yourself or do the research yourself. But anyway, the picture is more complex, as a cell also expends energy repairing DNA, and creating the enzymes to help in the formation of DNA, RNA, etc. As well as the histones and things. —Pengo ^{talk · contribs} 01:52, 13 November 2006 (UTC)

[edit] DDT ppm of quail

Can anyone help me find some figures for average DDT ppm of a quail diet? I only need one, but several is always better. Thanks! X [Mac Davis] (DESK|How's my driving?) 01:35, 13 November 2006 (UTC)

200 ppm if they're being experimented on by the Animal Science Department, North Dakota State University. —Pengo ^{talk · contribs} 01:57, 13 November 2006 (UTC)

Most of the experiments are 200 ppm, but I'm not sure if that is the "normal" dosage. X [Mac Davis] (DESK|How's my driving?) 03:39, 13 November 2006 (UTC)

Is this for real? Not only does this question just sound ridiculous, but isn't DDT not really used commercially in the states and aren't most quails farmed, hence one would not think they had pesticides specific to their (quail) diet? This sounds like secret code for something to me, like "the pigeon has flown the coop, I repeat: the pigeon has flown the coop!" If something big goes down in the next couple of days, I'm onto you two! ;) Vespine 04:00, 13 November 2006 (UTC)

That's an absurd accusation. And furthermore, I'll have you know that the green vampire will eat 27 bananas at midnight. StuRat 04:25, 13 November 2006 (UTC)

Well, I meant environmental levels, attributed to a time and place. DDT is not used for agricultural purposes almost everywhere now. I'm looking for that of a wild quail, and I think 200 ppm is a few orders of magnitude greater than, "normal." Also, some species of mosquito (mostly in the Indian sub-continent) started evolving resistance, so the Indians poured it on, because they were stupid [1]. If the mosquitos are already immune ot it don't spend more money on it!! Also, good point, I don't believe anyone has created a reference frame like in measuring mean surface temperature anomalies. But there has to be a range. You could take levels now, or "then." X [Mac Davis] (DESK|How's my driving?) 05:54, 13 November 2006 (UTC)

and <gasp> DDT isn't carcinogenic. But it's replacements have been highly toxic to agriculture workers. More people have died from the replacement than would have died from DDT. Tbeatty 06:03, 13 November 2006 (UTC)

It's not accurate to say it's not carniogenic:

The EPA, in 1987, classified DDT as class B2, a probable human carcinogen, based on "Observation of tumors (generally of the liver) in seven studies in various mouse strains and three studies in rats. DDT is structurally similar to other probable carcinogens, such as DDD and DDE." Regarding the Human Carcinogenicity Data, they stated " The existing epidemiological data are inadequate....

Much more info is at DDT#Conflicting_Studies —Pengo ^{talk · contribs} 14:24, 13 November 2006 (UTC)

Then again...

The National Toxicology Program (NTP) determines DDT to be "reasonably anticipated to be a human carcinogen" based on the following evidence: "By stomach tube, DDT induced hepatomas in mice and rats of both sexes, and lymphomas and lung carcinomas and adenomas in mice. When administered by subcutaneous injection, DDT induced liver tumors in mice of both sexes (IARC 1974, 1987, 1991)... Administration of technical grade DDT, TDE, and p,p'-DDE in the diet provided no evidence for the carcinogenicity of DDT in mice and rats (NCI 1978)." In a 1567 monograph by Swiss physician Paracelsus, it was observed that "All things are poison and none are without poison," a phrase which is usually said "The dose makes the poison." It might be reasonable to anticipate that pumping large amounts of DDT directly into a human's stomach would be carcinogenic, but it is not reasonable to call DDT carcinogenic because of that (the EPA lists DDT as Class B2 carcinogen, alongside coffee and the profession of carpentry). Early claims of carcinogenicity were based on abnormally high total DDT (DDT and it's broken-down components) in blood serum of patients dying from cancer. However, cum hoc, ergo propter hoc (correlation does not necessarily imply causation), and these were probably a consequence of cancer causing mobilization of total DDT from adipose tissue (body fat). Better designs include the storing of numerous serum samples to wait until some of the subjects develop cancer, then compare total DDT levels in their stored sera with those of matched controls. One such study found a significant excess in breast cancer patients, but an analysis of six such studies yielded no conclusions. DDT's chemical makeup has been claimed to be close enough to that of oestrogen to offset human male hormonal balance. Although the statement is dubious, DDT could be partially responsible for declining sperm counts in European men. However, this decline has continued even though total DDT in sera and adipose tissue have also been declining, and it is very difficult to eliminate variables.

In April 1972, after seven months of testimony, EPA Administrative Law Judge Edmond Sweeny stated:

DDT is not a carcinogenic hazard to man… DDT is not a mutagenic or teratogenic hazard to man …The uses of DDT under the regulations involved here do not have a deleterious effect on freshwater fish, estuarine organisms, wild birds, or other wildlife. …The evidence in this proceeding supports the conclusion that there is a present need for the essential uses of DDT.

X [Mac Davis] (DESK|How's my driving?) 20:05, 13 November 2006 (UTC)

I'd ignore anything the EPA says during a Republican administration (1972 was under Nixon), as their purpose changes from "protecting the environment" to "protecting businesses which pollute the environment", under Republican leadership. StuRat 20:46, 13 November 2006 (UTC)

I find it a bit odd that Mac Davis would reply to an old study with an even older non-study (an EPA statement). My point was that DDT's carcinogenic properties are debatable, not that they are or are not significant. Arguing that DDT was not environmentally hazardous is just bizarre, especially quoting a 1972 EPA statement. —Pengo ^{talk · contribs} 00:22, 14 November 2006 (UTC)

I'm trying to keep down space. The older non-study would be the Judges final decision after 7 months of hearings on DDT. Afterwards, William Ruckelshaus disagreed and decided DDT was against the law. Don't think you can hate the EPA more than I do Stu! What do you mean arguing that DDT is not environmentally hazardous? X [Mac Davis] (DESK|How's my driving?) 17:08, 14 November 2006 (UTC)

[edit] Oil Well

When an Oil Well goes dry does it leave a cavern or giant hole where the oil had been? If so has anyone ever decided to go down inside one?67.125.159.230 02:19, 13 November 2006 (UTC)

No, the oil almost never occupies caverns or giant holes -- it occupies the tiny (often microscopic) pore spaces between the grains of sand or limestone or whatever was once other than rock and could therefore hold some fluid. As oil (or natural gas) is pumped, usually water rises to fill the pores. Geologyguy 02:42, 13 November 2006 (UTC)

Damn that means no Oil Well Speluncking, anyways thanks.

However, in the Netherlands areas that lie above the gas bubbles frok which natural gas is pumped have occasionally sunk and many houses have cracks in them. Is it different for gas or what is going on here? DirkvdM 11:40, 13 November 2006 (UTC)

The oil or gas that was originally there was under great pressure (indeed, it was that pressure that helped make it into oil and gas). Even if the space previously occupied by the oil or gas is immediately refilled with water, we've removed a lot of the mass of the overall subsurface oil/gas/water liquid system - so the net pressure is lower (just like opening the lid of a bottle of carbonated water, and resealing it once the gas has escaped). That pressure took part in supporting the layers of material above it, and with the pressure lowered the rocks above will sag a bit as a result. I'd guess that if you can see the difference at the surface, the gas reseve must be fairly close to the surface, and the rocks above the gas reserve not terribly strong. -- Finlay McWalter | Talk 11:52, 13 November 2006 (UTC)

Areas of oil extraction and water injection can have significant earthquake clusters, showing that the process does disturb the rock quite a bit. --Zeizmic 13:33, 13 November 2006 (UTC)

[edit] Do sapphires dull?

Do sapphires dull over time? I looked all over the Internet for the answer, but couldn't find it. If they indeed dull with the passage of time (or for any other reason), could someone provide a link where the effects of dulling would be described? Thanks. Xanon

Don't take my word for it, but I am not aware of precious stones "dulling." Dulling is usually from oxidation or chemical bonding with chemicals in the air, and I don't think sapphires would do that. X [Mac Davis] (DESK|How's my driving?) 03:42, 13 November 2006 (UTC)

"There are several folklores and legends associated with sapphire . To many religions sapphires blue color was representative of heaven. Sapphire has been a holy stone to the Catholic Church and to ancient Persians. Ancient priests and sorcerers honored sapphire above all gems, for this stone enabled them to interpret oracles and foretell the future. Ancients believed the Ten Commandments were written on a sapphire tablet. Marriage partners put great faith in the stone. If its luster dimmed, one knew his or her spouse had been unfaithful. Sapphire refused to shine when worn by the wicked or impure." http://www.jeweler.com/birthstone_jewelry_info_sapphire.htm So the sapphires probably do dim, although probably not due to the spouse being unfaithful. Xanon

I wouldn't be too sure about that. A lot of folklore doesn't have any basis in reality although some does. See Claudius Aelianus for one humorous example involving beavers. Chances are your stone is dirty. On the backside where the stone attaches to the ring it gets dirty often. Taking it to a jeweler would probably brighten it back up. 152.3.74.136 05:51, 13 November 2006 (UTC)

I don't have a sapphire, I am just looking to use that fact in a literary work. On the Internet, I have seen a lot of mentions of jewelry items dulling and needing to be cleaned. Could a sapphire be such an item? If not, could someone please provide an example of a precious stone that does dull over time? Xanon

I have read of some gemstones, probably sapphires, being irradiated to make the blue color more intense. Could that enhancement possibly fade over time, and the stone return to something closer to its original state? By the way, at first I thought you meant physical dulling, and was going to cite the lifetime for sapphire phonograph needles, which needed replacement less frequently than steel ones and more frequently than diamond ones, all things being equal. Edison 17:36, 13 November 2006 (UTC)

The gemstone that is typically irradiated to make it more blue are blue topaz. JBKramer 17:40, 13 November 2006 (UTC)

Sapphire is a very hard mineral, so it does not scratch easily (or dull from abrasion). However, it is just crystaline Aluminium_oxide, which it is chemically reactive, especially to acids. I cannot find any information about it dulling chemically, but I'd certainly keep them clean and dry. --Ronz 02:41, 16 November 2006 (UTC)

[edit] High quality gyroscope

Where would I purchase a high quality scientific demonstration gyroscope (not a toy) in the UK?--Light current 04:45, 13 November 2006 (UTC)

A bicycle wheel mounted on handles does a much better job for most demos - commercial gyroscopes spin far too quickly for students to really grasp that the concept exists. What are you trying to demo specifically? JBKramer

I want one for home use/experiments/novelty/visual impact!--Light current 23:41, 13 November 2006 (UTC)

[edit] Do spiders sleep?

Do spiders sleep? My boyfriend and I got into a curious debate over the topic. Neither of us could find any information anywhere, so I thought I'd ask here. ♠PMC♠ 04:56, 13 November 2006 (UTC)

From article sleep - "Sleep is the state of natural rest observed in most mammals, birds, fish, as well as invertebrates such as the fruitfly Drosophila." If flies can sleep spiders probably can, although I seriously doubt they can dream. It probably is more like a resting state. 152.3.74.136 06:02, 13 November 2006 (UTC)

They seem to be still for 90% of their life, so you could call that "sleep", if you want. StuRat 07:47, 13 November 2006 (UTC)

First google hit for spiders sleep: depends on how you define "sleep". Weregerbil 10:29, 13 November 2006 (UTC)

Scientists still don't know what sleep is or what its purpose is. There is a lot of controvercy over whether any other animals apart from humans 'sleep' in the same way we do. Although a lot of animals rest, there is no way of telling whether they are sleeping. Englishnerd 14:46, 13 November 2006 (UTC)

It is, however, well-known that all mammals sleep. Much of the research about sleep is done on cats, since they sleep ~20 hours/day. howch e ng {chat} 22:41, 13 November 2006 (UTC)

From my own observation of my dog and cat I would suggest that at least all mammals sleep in the same way, i.e., R.E.M. sleep, etc. --150.101.153.110 21:15, 13 November 2006 (UTC)

Same, my dog sometimes behaves as if dreaming. --Wirbelwindヴィルヴェルヴィント (talk) 05:54, 14 November 2006 (UTC)

Huh...well, there that is. Okay, thanks, everyone. ♠PMC♠ 19:47, 14 November 2006 (UTC)

[edit] Biodegradable Corrosion

What is biodegradable corrosion? How is it different from microbiological corrosion? What are the methods to prevent it?Swati Bhise 05:38, 13 November 2006 (UTC)

I suppose rust (iron oxide) is "biodegradable corrosion", as even the rust will eventually break down and dissolve in the rain. StuRat 07:45, 13 November 2006 (UTC)

Are you sure you have the term right ? Doing Google searches, I've found the phrases "biodegradable corrosion inhibitor" and "biodegradable corrosion protector". In both cases, I take this to mean that the biological agent prevents corrosion. In short, there doesn't seem to be any mention of "biodegradable corrosion". There is "biological corrosion", of course, if that's what you mean. StuRat 04:18, 14 November 2006 (UTC)

[edit] tower construction

I've looked at the usual article suspects and can't seem to locate and answer. Towers are used in arid agricultural areas as water pump power, more or less everywhere for radio antennas, and so on. A common construction techniques are mentioned, but not the one I thought I remembered. There is a tower design made of several different sizes of triangles (from the usual materials, steel angle iron, tubing, etc) which looks rather like it was laid out by someone on an LSD flashback. All jumbled impossibly together. They really don't look like they should stay up at all. But I have a tag in my mind that this odd design is least expensive to design, or easiest to erect, or cheapest materials, or lowest mass for a given height, or some such. The trouble is I can't remember anything else about this peculiar sort of tower construction.

I don't remember anything taller than perhaps 40 feet or so, so it may be that the design doesn't scale well. Or not. Anywaya, does anyone have a name, or a reference? An explanation of what's special about the design technique? Anything? ww 07:02, 13 November 2006 (UTC)

Never heard of it. Most towers now are computer-designed and quite clean. --Zeizmic 13:31, 13 November 2006 (UTC)

There are no pictures in this article, but perhaps you were remembering a Tensegrity tower? These are designs that are based on a distinct separation between compressive and tensile forces, and many certainly fit your description of a deisgn that "was laid out by someone on an LSD flashback". Google probably has images Bute here's one: http://www.kennethsnelson.net/icons/scul.htm

Atlant 14:18, 13 November 2006 (UTC)

[edit] scarlet fever

hi i had scarlet fever as a 5yr old and i was just wondering how rare it actually is, like 1 in how many people get it, i'm just very very curious and i cant find much about it other than the symptoms on the net thanks skye

That would depend on your age, as it used to be quite common but is now quite rare. Your location also matters. StuRat 09:20, 13 November 2006 (UTC)

ok, well i just turned 19 so it was around '92 in australia, but i am alson interested in other places, just anything anyone might know about it.

Well, it's uncommon, but not exactly rare, in Australia. In 2003 they had an "outbreak" of 13 possible cases in Perth: [2]. StuRat 09:52, 13 November 2006 (UTC)

Two measures of how common a disease is are its incidence and its prevalence. "Incidence" is how many new cases are seen, while "prevalence" is how many cases exist. The annual incidence of scarlet fever in the Oxford region of England was 0.3 cases per 1000 per year in 1983 (so that would be 3 new cases a year in a population of 10,000). Peak incidence is in children 4 to 8 years old. 80% of children aged 10 or older have protective antibodies against streptococcal pyrogenic endotoxins. (But of course these need not be due to clinical cases of scarlet fever). - Nunh-huh 13:24, 13 November 2006 (UTC)

Scarlet fever is not rare (as evidenced by the numbers) and is simply the skin's reaction to a common bacteria (the strep in strep throat). It is not a reportable disease and numbers are bound to be unreliable. I know I personally had it and have seen a ton of cases. I generally don't even tell the parents that it's "scarlet fever" because of the connotations and the fact that it's really nothing to fear above and beyond the strep infection. InvictaHOG 01:18, 14 November 2006 (UTC)

Scarlet fever is reportable in some jurisdictions, and not reportable in others. - Nunh-huh 05:35, 14 November 2006 (UTC)

[edit] Lime

Lime as a component of organic toilets. Will it help break down matter. Kind regards. Robert Tedge, Australia.

Do you mean the mineral or the fruit ? StuRat 09:55, 13 November 2006 (UTC)

Not the fruit, surely. Calcium oxide mentions a number of effects for which it is used in sewage treatment. ×Meegs 11:45, 13 November 2006 (UTC)

Well, enzymes in some fruit, like papaya, do help to break down some foods, so it's not completely impossible that lemons or limes could do something similar. StuRat 20:33, 13 November 2006 (UTC)

Oddly, composting toilet doesn't seem to mention it. Woodash is often added to the contents of shit pits and I believe the same goes for lime, but I don't know the reason. DirkvdM 11:46, 13 November 2006 (UTC)

Quicklime or Calcium oxide is very nasty stuff, used by the mafia on dead bodies. Organic toilets use bacteria, moisture, heat and oxygen to break down waste. I have one at the cottage. Your whole effort with these things is to keep the little critters happy. If they get sad, the whole place fills up with stink! Every few months, you get a nice pile of clean compost which you throw in the forest. --Zeizmic 13:28, 13 November 2006 (UTC)

Lime was the standard stuff to toss into the pit in an outhouse (well, that and pages from the Sears and Roebuck catalog); I don't know its chemical effects on human waste, though.

Atlant 14:23, 13 November 2006 (UTC)

There are two kinds of lime mentioned in relation to outhouses, not sure of the details, but one is quicklime and the other isn't. I've read that it keeps down the smell but actually delays and interferes with the biological breakdown of the waste. It was probably the same lime used to correct excess acidity in fields on farms, because that would have been handy. Edison 17:40, 13 November 2006 (UTC)

A solution of lime (actually CaOH when hydrated) will hydrolyze protein if it is concentrated enough. It will also convert fats to the calcium salts of fatty acids. No idea what it will do to carbohydrates. Seems reasonable that it would help breakdown most types of biological waste, but as mentioned above, also inhibit microorganisms that could also help with this. ike9898 20:42, 15 November 2006 (UTC)

[edit] Magnets

A bar magnet is a rectangular parallelopiped and its 2 ends are the north pole and the south pole. So what are the other 4 sides?

In between. :) DirkvdM 11:54, 13 November 2006 (UTC)

They are the sides. If you look at the image at Magnet, you can see how the field lines go for a bar magnet. By the way, the cross section of a bar magnet does not have to be a rectangle; it could as well be a cylinder with a circular cross section. --Lambiam ^Talk 11:52, 13 November 2006 (UTC)

Or any other shape for that matter. It could also be a bar with the poles at the sides in stead of at the ends. But that would have the magnetic force spread over a larger surface, so it would generally be less useful. DirkvdM 11:57, 13 November 2006 (UTC)

It would not be what is generally understood by the term "bar magnet". --Lambiam ^Talk 11:08, 15 November 2006 (UTC)

It wouldn't be less useful, it would just have a different use. A refrigerator magnet, for instance, usually has the poles on the largest (flat) surfaces instead of the smaller edges. -- Plutor ^talk 13:13, 13 November 2006 (UTC)

Every part of a magnet is also a magnet, so if you'd cut a piece out of a magnet that would also be a magnet, but I'm not sure if that's what you mean. Are you referring to the direction? In the sense that at one side you've got one pole, at the opposite side the other pole and what do you have at the four remaining sides? I don't think there is a name for that. DirkvdM 11:54, 13 November 2006 (UTC)

Exactly half of the magnet is the north pole and the other half the south pole. RevenDS 13:11, 13 November 2006 (UTC)

Your teacher is trying to trick you into saying east pole and west pole!--Shantavira 13:14, 13 November 2006 (UTC)

FYI re composite refrigerator magnets: The flat refrigerator magnets (that are used as advertisers and souvenirs, e.g., "Wikipedia: your place to be bold!") are often constructed with alternating north and south poles on the same surface of the plane; you can feel this if you take two similar (or identical) refrigerator magnets and slide them against each other with the "magnetic" sides facing each other: the magnets will alternately repel and attract as you move a few millimetres. This construction is more effective at keeping the large planar magnet uniformly stuck onto the steel 'fridge than a uniformly-polarized magnet would be. But this tends to make these magnets less useful for hacking.

Atlant 14:31, 13 November 2006 (UTC)

IDKT. Do we have an article on that sort of thing? Fridge magnets? Im serious! 8-)--Light current 16:30, 13 November 2006 (UTC)

See Refrigerator magnet. This article could definently use some expansion. ike9898 16:40, 13 November 2006 (UTC)

[edit] Why do the really huge gulls have eyes located on the sides of their heads?

Doesn't that mean that evolution has designated them as prey animals? Was there something around in the past that could take the really big gulls on the wing? That's quite scary if you consider how violent they are. --84.68.125.122 12:45, 13 November 2006 (UTC)

Move along, nothing to see here. JBKramer 13:48, 13 November 2006 (UTC)

Propose delete above comment?--Light current 16:28, 13 November 2006 (UTC)

See the talk page. JBKramer 16:39, 13 November 2006 (UTC)

Some answers:

the eyes on the side are to help the more vulnerable young look out
evolution hasn't had time to move the eyes forward, as the larger gulls are still closely related to the smaller ones. Or there simply isn't the evolutionary pressure to do so.
even eagles appear to have their eyes pointing in fairly different directions. Are you sure larger gulls eyes are the same as the smaller ones?

—Pengo ^{talk · contribs} 13:57, 13 November 2006 (UTC)

Just a guess: gulls and eagles have relatively narrow heads. This helps to reduce air resistance in flight. It makes no evolutionary sense to have eyes pointing forward on a narrow "face" - the eye base is too small. Owls have forward pointing eyes, but (for the same body weight) owl heads are much broader than gull heads. A hypothetical gull "design" with eyes pointing forward would probably be inferior to fish owls. Again, this is just a guess. --Dr_Dima.

(After edit conflict) Anyone know how closely related the large gulls (e.g. the herring and great-black backs) are to the small ones, e.g. black-headed gulls (which do have lots of predators)? It'd be interesting to find out which evolved from which and how recently - therein probably lies the answer. Humans have also removed or reduced the numbers of many of the predators capable of taking the big ones in the last few hundred years too (the large raptors for example) - not really long enough for evolution to give them the forward-facing eyes of a top predator. --Kurt Shaped Box 16:43, 13 November 2006 (UTC)

Kurt, I think the following reference: http://mbe.oxfordjournals.org/cgi/reprint/17/12/1797 gives at least a partial answer to your question. Regards, Dr_Dima.

[edit] Name the fish!

...species?

The closest I could come up with is the Black-Banded Leporinus (Leporinus fasciatus). Unfortunately WP has no article on this particular species. Here's a Google image search. Is this your fish? ---Sluzzelin 20:58, 13 November 2006 (UTC)

It certainly appears to be the one, thanks! —Pengo ^{talk · contribs} 23:34, 13 November 2006 (UTC)

I've moved the image now to reflect its species. —Pengo ^{talk · contribs} 00:12, 14 November 2006 (UTC)

[edit] Long Range Gravity

I honestly should get my own handle.

Here's another big old physics question. There's some formula for gravitational attraction force between two object (Kepler's doing?), equivalent to... G(m1+m2)/R^2 (if my memory serves me well).

My question: at some point, does gravity just go away? If we put two equal point masses with a mass of 1 kilogram 100 light years apart, will they eventually collide? Lets make this some ideal universe, i.e. no radiation, other gravitational sources, etc.

What happens? --138.29.51.251 16:46, 13 November 2006 (UTC)

General Relativity says they eventually collide - the math is left as an exersize for the reader. If gravity is quantized, they may not collide, read Quantum gravity, though I believe that article may suffer from POV innacuracy, so tread lightly. JBKramer 16:55, 13 November 2006 (UTC)

Gravity does not go away but reduces as the square of the distance as your formula shows! 8-)--Light current 16:56, 13 November 2006 (UTC)

The standard gravitational formula, due to Isaac Newton, is $F=\frac{Gm_1m_2}{r^2}$ . Your formula would give non-zero forces on objects from other objects with 0 mass. --Tardis 18:45, 13 November 2006 (UTC)

Note that there is a gravity-related formulat that has m1+m2 in it rather than m1 m2, but it's the formula for orbital period as in Kepler's Third Law.

Thinking about this, I became curious enough to see what the behavior of those two 1 kg masses would be in Newtonian physics. Their initial situation is a degenerate case of an elliptical orbit; they will complete 1/4 orbit before colliding. If I compute correctly, Kepler's Third Law gives a period of 5.006e32 seconds for the full orbit, so the time to collision would be 1.251e32 seconds or just under 4 septillion (American style) years. Their gravitational potential energy would be 7.05e-29 joules, half of which would go into kinetic energy for each object, so their speed on impact -- if "impact" is the word I want -- would be5.93e-15 m/s or a bit over 7 inches per million years. If I compute correctly. --Anonymous, 06:10 UTC, November 14.

About a month after this was written, it was called to my attention that the while the motion in Newtonian physics is indeed a degenerate case of elliptical orbit, it's not the same elliptical orbit I had in mind. The bodies actually complete 1/2 orbit before colliding -- the apoapsis is their original separation and the periapsis is zero. This reduces the time by a factor of sqrt(2), so if my calculation was otherwise correct, the actual time is 8.85e30 seconds or a mere 2.8 septillion years. --Anonymous, note added to archive December 18, 2006, 18:25 (UTC)

Handle? Somebody into radio? Gravity never "goes" away—see inverse square law.X [Mac Davis] (DESK|How's my driving?) 20:08, 13 November 2006 (UTC)

If they are moving away from each other fast enough, they will never collide. If both are at rest, they will.

While all of these answers are definitely right for standard newtonian and einsteinian gravity, given the large distance and small size of the masses, some branches of Quantum gravity theory (unproven) argue that gravity is quantized and that the quantum is too large for there to be any force at all between the objects given the distance and the mass. JBKramer 20:29, 13 November 2006 (UTC)

Thanks, JBKramer, that's sort of what I'm looking for. Any more info?--138.29.51.251 20:51, 13 November 2006 (UTC)

I lack the appropriate background to speak intelligently about Quantum Gravity, which is an advanced theoretical possibly garbage theory that has not been experimentally tested. It would take extensive post-graduate theoretical physics knowledge to even start thinking intelligently about QG. I lack such. JBKramer 21:23, 13 November 2006 (UTC)

Actually it's an entire class of theories which share the common feature that we won't be able to test them for a very long time, because gravity is very weak. An interesting exception is theories of large extra dimensions (no article... there should be!) in which only gravity propogates; in these cases gravity looks week at macroscopic distances, but becomes quantum mechanical at much lower energies, leading to testable theories of quantum gravity. -- SCZenz 22:54, 13 November 2006 (UTC)

Can this also go to say that I am (or any other mass in the universe) currently being attracted by every other mass in the universe? I know that the Earth is pulling on me, the moon is pulling on me, and the Sun is pulling on me, but does that go for every other mass in the universe?Ed Dehm 05:26, 14 November 2006 (UTC)

According to the currently-accepted best theories of gravity, yes. Other bodies actually do have a measurable effect on you, and in fact on the solar system (or galaxy!) as a whole. See for example the Great Attractor. -- SCZenz 05:30, 14 November 2006 (UTC)

[edit] Identical "non-twins"

What are the chances of 2 brothers or sisters, born at different times, i.e. not twins as such, having the same genetic information? I know it is slim but has it ever been recorded to happen and what are the consequences/results of this?

Yours, christopher

Functionally impossible to have exactly the same info. Read Meiosis and Genetic recombination for the exact reason, but suffice it to say that the chances are the same as flipping heads about a million times in a row - nonexistant. JBKramer 18:01, 13 November 2006 (UTC)

The chances are 2^46, if you don't start by assuming they are the same sex, and 2^45, if you do. That ignores gene cross-linkage, mutation, etc. which would make the chances even lower. Since that's 1 in 70 trillion or 1 in 35 trillion, which are both far more than the number of people who ever lived, it's quite unlikely to have ever happened. However, if the parents are related (share chromosomes), the chances become much better. StuRat 20:19, 13 November 2006 (UTC)

No, it's much much harder than that, because you're ignoring Chromosomal crossover. JBKramer 20:23, 13 November 2006 (UTC)

That's in the "etc." that I said we were ignoring. StuRat 20:25, 13 November 2006 (UTC)

I think it's possible for the egg to be fertilised and split into two embryos, then you take out the second one and deep freeze it, let the first one be born normally, then reimplant the second one into a surrogate mother. I'm not sure though. --WikiSlasher 11:20, 14 November 2006 (UTC)

Freezing it would create ice crystals, which would then puncture it. I's just like freezing fruit, it never tastes as good. | AndonicO ^{Talk | Sign Here} 18:23, 14 November 2006 (UTC)

Not if using cryopreservation, "[Human] embryos that are 2, 4 or 8 cells when frozen ... pregnancies have been reported from embryos stored for 9 years. ... Many studies have evaluated the children born from frozen embryos (“frosties”). The result has uniformly been positive with no increase in birth defects or development abnormalities." Vespine 22:05, 14 November 2006 (UTC)

Indeed. Eggs are routinely harvested from female donors for later use or use by others, and these are stored in a frozen state. Sperm can be preserved as well. See Embryo transfer. Robovski 00:58, 15 November 2006 (UTC)

[edit] vacuum container

Hi can anyone tell me,what is a container that insulates its contents from outside temperatures by the use of a vacuum.

Is it a flask of some kind. Thanks P LPetelangley 18:07, 13 November 2006 (UTC)

Vacuum flask. Yes. JBKramer 18:17, 13 November 2006 (UTC)

A small one used to keep food or drink hot or cold is called a thermos. StuRat 20:12, 13 November 2006 (UTC)

It is a Dewar flask, invented 1892. Edison 01:51, 14 November 2006 (UTC)

[edit] copper vs iron

if i were to light a fire and put a cast iron pot into the flames, then place copper into the pot would the copper melt? as so i could pour it into a mould? thankyou. lwnicklin

According to Copper copper melts at 1084.62 °C, and Iron at 1538 °C. However, that's hotter than wood burns, so you'll need to use something hotter, like a blowtorch (I think). But, yes, you could melt copper in an iron pot. However, this experiment is dangerous. Do not attempt it without a traned professional metalurgist around. JBKramer 19:18, 13 November 2006 (UTC)

Coal would probably burn hot enough. Maybe charcoal briquets?

You need a crucible lined with refractory material to stop the heat escaping. Also you are going to need a fuel which can burn at white heat and you are going to need a lot of air to make it do so! Supplied by a bellows probably. Maybe coke is the correct fuel?--Light current 21:49, 13 November 2006 (UTC)

You shouldn't need "white heat"; it's not for nothing that the ancients smelted copper before iron; see Bronze Age. I think a charcoal fire is probably sufficient. I know for a fact that the coals of an ordinary fireplace-style wood fire will melt the tin that forms the core of modern American pennies although I can't remember ever successfully melting an older bronze penny using just a fireplace fire.

Atlant 18:31, 14 November 2006 (UTC)

[edit] Latitude and longitude of place

A few years ago I visited a small town in Sichuan province of China.That town was called Renshou.Could anybody tell me the exact geographic coordinates(latitude and longitude) of that town so that i could search it in GoogleEarth Thank You amrahs 19:26, 13 November 2006 (UTC)

Searching for Renshou, China on Google brings this site http://www.fallingrain.com/world/CH/7/Renshou.html which says. Lat: 27° 7' 60N Long: 117° 49' 60E. Not very high-resolution pictures in GoogleEarth tho. --Phydaux 19:53, 13 November 2006 (UTC)

Is it this Renshou? --Bowlhover 19:55, 13 November 2006 (UTC)

[edit] peanut butter and throat cancer

Is there a statistical correlation between peanut butter sales and throat cancer? Not asking if there's a direction of causality, just if there's a statistical correlation between the two? Anyone know? 19:31, 13 November 2006 (UTC)64.12.116.74

A quick view of pubmed results seems to show most research is geared toward peanut butter (really Aflatoxin) and liver cancer. I'm no where near an expert, however, and have no idea about throat cancer. --TeaDrinker 19:45, 13 November 2006 (UTC)

A Google search for "peanut butter" "throat cancer" turned up nothing that would support a link. In fact, NCH Healthcare recommends peanut butter for weight maintenance while on radiation therapy. -- Scientizzle 19:49, 13 November 2006 (UTC)

It has also been scientifically determined that peanut butter has no effect on the rotation of the Earth: "The Effects of Peanut Butter on the Rotation of the Earth". La ï ka 13:17, 14 November 2006 (UTC)

Do see Aflatoxin, though.

Atlant 18:34, 14 November 2006 (UTC)

[edit] what are skin parts and their functions?

Removed keyboard spasam

Try starting with the skin article. --TeaDrinker 20:05, 13 November 2006 (UTC)

Or we could use this handy template:

Welcome to Wikipedia. You can easily look up this topic yourself. Please see Skin. For future questions, try using the search box at the top left of the screen. It's much quicker, and you will probably find a clearer answer. If you still don't understand, add a further question below by clicking the "edit" button to the right of your question title. X [Mac Davis] (DESK|How's my driving?) 20:09, 13 November 2006 (UTC)

[edit] How is this name spelled?

Wverm? wervm? verm? werm? wevrn? Its another name for a dragon. Wikipedia links are prefered. IP

Old English wyrm meaning snake or serpent. Gandalf61 20:41, 13 November 2006 (UTC)

Thank You. Now I can study.

or Wyvern. EamonnPKeane 20:51, 13 November 2006 (UTC)

[edit] Evolutionary seeding or illness leading to differences in psychology?

We seem to consider certain types of mental "wiring" to be abnormal or an illness but is this correct in all cases? Is it not possible that different types of mental processing as brought out in a species as part of evolutionary seeding? I can imagine that depending on the environmental state some types of behavior would be more successful than others. An example may be the way that some people are considered to be highly valued during a violent conflict such as a war and then spurned or even incarcerated during peace time. Assuming there is no observable physical anomaly, what is mental illness and what is natural diversity? Is it a matter of divergence from the perceived societal norm? --150.101.153.110 21:30, 13 November 2006 (UTC)

It's possible. See Anti-psychiatry. Again, article may suffer from point of view problems. JBKramer 21:34, 13 November 2006 (UTC)

Evolution has led to some rather evil behavior, like genocide. So, I'm not sure it's valuable to classify people as "normal" and "abnormal" so much as "contributes to modern society" and "is a detriment to modern society". StuRat 22:46, 13 November 2006 (UTC)

For some genetic predispositions towards mental illness there may no real benefit from the pathology in any environment (Psychosis: a costly by-product of social brain evolution in Homo sapiens). However, I suspect that there has been positive selection for diversity in human brain functions, particularly for genetic diversity that results in valuable behaviors at young ages. For example, genes that provide a predisposition towards creativity might be retained in a population even if they also cause a predisposition to mental illness and death in the third or fourth decade (Schizotypy, creativity and mating success in humans). The effects of genes and environment on Schizophrenia seems to be very complex. --JWSchmidt 03:41, 14 November 2006 (UTC)

in general, variation is highly liked by evolution. Even 'extremes' can be useful, since natural selection can't happen if there's no variation to begin with. The thin line between "mental illness" and "natural diversity" is mostly a cultural/society thing. Of course, some things are obviously just 'diversity', where as some things are obviously an 'illness' or 'abnormality', but there is a large fuzzy grey area in between. Check out Autism rights movement for an example - where autistic people are demanding for 'understanding' rather than a 'cure', claiming that their condition is not an illness, but merely a different way of being. --`/aksha 03:52, 14 November 2006 (UTC)

[edit] More gravity (sorry)

I was thinking about how long it would take for an object's gravitational waves to effect something. Since there is that handy law of conservation of matter, no object with mass can be created and suddenly have gravity. Therefore, it would be silly to regulate gravity 'waves' to the speed of light since there is always a continuous presence (stars continuously generate light, but that's different, since light can be created or not created, while gravity is just a property of mass).

Since I couldn't give gravity a 'speed', it occured to me: is there a constant center of mass/gravity for the entire universe?

Say I wanted to communicate with another planet that was pretty darn far away. If they had some sensor that was extremely sensitive to gravity, is there anything that I could do on my planet that would register a change in that sensor if we were the only two objects in the universe? Assume ideals, i.e. no radiation, no orbits, everything is just perfect.

The followup question would be: what is the 'speed' of gravity?

Read Center of Mass. There is a body of evidence that Gravitational waves exist and that they move at the Speed of Light. In fact, the 1993 Nobel was awarded for measuring them. JBKramer 23:05, 13 November 2006 (UTC)

I believe the center of mass is everywhere. I think a two dimensional analogy is the surface of an inflating baloon. Every point moves away from every other point but there is no center. I believe the speed of the effect of gravitational changes due to movement is the speed of light. --Tbeatty 23:08, 13 November 2006 (UTC)

As far as I understand it, and I am far from an expert, pretty much any, and all information is limited to (near) the speed of light. Even purely 'observation' can only happen at the speed of light. Vespine 00:02, 14 November 2006 (UTC)

You are correct in that understanding 8-)--Light current 01:05, 14 November 2006 (UTC)

Why can't we give gravity a speed? E=mc^2, so it is possible to create mass from energy. Particle accelerators do it all the time. I know that the particles created will have very little gravity, but it isn't absurd to say "what might the speed of gravity be if we could measure it?" I agree with the other editors that gravity travels at the speed of light.

As for the second question (how to communicate with another planet): how about detonating a few hydrogen bombs, to destroy a few kilograms of mass? --Bowlhover 02:42, 14 November 2006 (UTC)

Its 'c'--Light current 02:44, 14 November 2006 (UTC)

Gravity works on energy, not just mass. Destroying mass won't change the gravitational pull of something at all, except insofar as it makes it "spread out," which will only be visible from short distances. -- SCZenz 05:31, 14 November 2006 (UTC)

If the aliens had an extremely sensitive sensor, then simply moving a large mass towards and away from them would be detectable. Naturally, the speed of that communication would be limited to the speed of light. — Knowledge Seeker দ 03:01, 14 November 2006 (UTC)

Looks like no ones talking to us though. See LIGO--Light current 03:04, 14 November 2006 (UTC)

If the escape velocity of a black hole is larger than the speed of light, how are we able to measure it's gravitational waves? --V. Szabolcs 10:37, 14 November 2006 (UTC)

Does it produce any gravity waves?--Light current 14:14, 14 November 2006 (UTC)

::: Yes, it has a similar relativity effect on space time as another large mass (bending light, etc.)

[edit] hyperbaric oxygen treatment for hepatitis c

75.22.79.191 23:54, 13 November 2006 (UTC)has hyperbaric oxygen been used anywhere in the world for hepatitis C?

Possibly, but a pubmed search reveals no articles written about it. If someone has done it, they haven't told the medical community through the usual channels. InvictaHOG 01:11, 14 November 2006 (UTC)

[edit] one atmosphere of pressure??

I was reading an article that claimed that a reaction caused one atmosphere of pressure, how much is this in grams or pounds etc???? can it be quantified this way? Rob

Atmosphere (unit) ≈ 1.033 227 452 799 886 kg-force/cm2 ≈ 14.695 948 775 5134 pounds-force per square inch (psi) -- Scientizzle 23:58, 13 November 2006 (UTC)

Google has a pretty neat trick that it seems too few people are aware of - search for a unit conversion and it will calculate it for you. For example, try Googling 1 atm in psi and see what you get. So far, I've found it capable of handling most commonly used units. Confusing Manifestation 08:15, 14 November 2006 (UTC)

And some uncommon ones as well like [3]

Atmosphere (unit) ≈ 1.033 227 452 799 886 kg-force/cm2 ≈ 14.695 948 775 5134 pounds-force per square inch (psi)

Are you sure ;-) ? Does that include or exclude the effect of butterfly sneezes?

Atlant 18:41, 14 November 2006 (UTC)

[edit] neo-natal cord care

i would like to ask what was the correct way of cutting the umbilical cord of the new born babies.

See umbilical cord if you have the stomach for it! 8-)--Light current 00:11, 14 November 2006 (UTC)

Afix two sterile clamps to the cord at about 10cm and about 20cm, cut with sterile shears. After a few hours it will dry out, and it will fall off after a day or two. Don't pull it, don't remove the clamps once they are clamped. Tuckerekcut 01:07, 14 November 2006 (UTC)

Typically we use clamps in the delivery room to stop the flow of blood in the cord and then cut just above (away from the baby) the clamp. This leaves a small stump and the clamp attached to the baby. The clamp generally comes off before you leave the hospital and the cord dries up and falls off in the next week or two. There is no reason to mess with the cord once you are out of the delivery room - no cleaning, pulling, picking, or cutting of the stump is required! InvictaHOG 01:09, 14 November 2006 (UTC)

How does it work for animals who have no clamps? (or scissors)--Light current 01:15, 14 November 2006 (UTC)

On kittens it remains as a little dried up stick looking thing that falls off aftr a few days. But one wonders how they survive without nurses and doctors to apply sterile clamps. Edison 01:55, 14 November 2006 (UTC)

The mortality rate during birth and during the neonatal period is much higher for these animals than for humans. — Knowledge Seeker দ 03:04, 14 November 2006 (UTC)

I don't have children yet and never witnessed childbirth, is there ever any reaction from the infant when the cord is clamped or cut? I imagine there wouldn't really be any nerves in the cord itself, does the child seem to even notice? I found the article on Lotus Birth quite interesting. Vespine 01:18, 14 November 2006 (UTC)

I have never noticed a reaction. — Knowledge Seeker দ 03:04, 14 November 2006 (UTC)

When I was little my mother told me that the doctor ties a knot in the end of the umbilical cord that stays attached to the baby, and that's what forms a person's navel. So that's not true? The funny knot-looking part inside a navel is not really a knot, but just forms naturally as the navel heals? (I am serious, until reading the above answers, I believed my mother about the knot!) 192.168.1.1 7:15PM, 13 November 2006 (PST)

I've only delivered about 100 babies, but I've never tied a knot in an umbilical cord. It forms naturally I think -- Samir धर्म 03:51, 14 November 2006 (UTC)

Are "innie" and "outie" navels the result of umbilical cord clamping/cutting practice, or else why are there such marked differences in navel appearance later in life? Edison 14:24, 14 November 2006 (UTC)

I was told (when I was a child and I asked my mum this question) that 'outies' result from the doctors clamping the umbilical cord too far from the baby's body. I don't know if this is actually true or not. --Kurt Shaped Box 20:38, 14 November 2006 (UTC)

It's not common practice to tie knots in the cord; I've never seen it, at least in America. It would be difficult to do, though anything which places pressure on the cord vessels would work to stop the bleeding. The belly button scar results from the natural scarring process after it falls off. Innie and outie happen naturally. InvictaHOG 14:33, 14 November 2006 (UTC)

Mines a deep pit. But others Ive seen are like little push buttons.--Light current 14:34, 14 November 2006 (UTC)

Cool, thanks for all the answers! I never knew I'd ever find out that Mom was just pulling my leg all those years! Okay, next question: What does the umbilical cord connect to inside the baby? I assume the vein & artery in the umbilical cord join a vein and an artery inside the fetus in a "T" configuration... what other structures or things are behind the navel, so to speak? 192.168.1.1 6:50 pm, 14 November 2006 (PST)

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