Wikipedia:Reference desk/Archives/Science/2008 July 27

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July 27

Where is you stomach?

sorry to be so stupid, but can anyone say whether thestomach is above or below the diaphragm in human. —Preceding unsigned comment added by 79.76.140.78 (talk) 00:57, 27 July 2008 (UTC)

Below, definitely below. The diaphragm acts as a barrier between the upper Thoracic cavity (containing the heart and lungs) and the lower Abdominal cavity (containing the stomach, liver, intestines etc.) — Jack (talk) 01:07, 27 July 2008 (UTC)

This image is way simplified, but it should be good enough for your needs. --Shaggorama (talk) 01:23, 27 July 2008 (UTC)

The stomach is actually located at the level of our belly-button or navel.It is located in our abdominal cavity, which is obviously below the Diaphragm.117.201.97.83 (talk) 19:00, 27 July 2008 (UTC)

A better description would be that your stomach is on the left side of your abdomen, extending up from the belly button to the diaphragm (bottom of rib cage). Make a fst with your left hand, put your thumb on top of your bottom rib with your knuckles roughly in line with your left nipple, and that's about where you're stomach is. Here's a better image for you --Shaggorama (talk) 08:02, 28 July 2008 (UTC)

Polycarbonate against glass causes oily looking adhesions

I recently bought a case for my iPhone. The case has a thin polycarbonate protective screen that sits on against the iPhone's glass screen. I notice that there are areas where the glass and polycarbonate rest against each other. In bright light, these areas look dark and oily with a rainbow refraction around the perimeter. If I squeeze the case, I can get the polycarb to lift away from the glass and these areas disappear. What causes this weird oily/wet areas and rainbow refraction? How can I prevent it? --70.167.58.6 (talk) 01:20, 27 July 2008 (UTC)

Did you clean your screen before putting it on? It may simply be moisture or grease from your fingers. --antilived^{T | C | G} 02:08, 27 July 2008 (UTC)

It sounds like a interference pattern like newtons rings. Ask for more details.87.102.86.73 (talk) 10:13, 27 July 2008 (UTC)

Yes, Newton Rings! Here's a photo [1] (sorry, I don't know how to post to Wiki commons). Both surfaces have been cleaned over and over with lens cleaner and microfiber cloth. --70.167.58.6 (talk) 22:30, 27 July 2008 (UTC)

yep, thin film interference, unless if you find a way to suck out all the air at the interface, then I don't know how you'll be able to fix it. Coolotter88 (talk) 18:53, 28 July 2008 (UTC)

The insecure narcissist?

Are there any psychological terms that would describe someone as being both a narcissist and having low self esteem (two seemingly antithetical personalities)? --70.167.58.6 (talk) 01:24, 27 July 2008 (UTC)

You might throw anorexia or other eating disorders up there, at least maybe as a consequence of the above combination. I hesitate to suggest that though because as I understand it, narcissism is more than self-obsession: it's self-love. That kind of egoism would presumably be wrapped in strong self-esteem, so what you are suggesting may be an analytic impossibility (like a square circle). --Shaggorama (talk) 04:08, 27 July 2008 (UTC)

Many personality disorders are often attributed to the opposite being true - hence the term 'disorder' - as such and analytical impossibility is (irrelevent) and actually is indicative of the disorder itself...

There is an article Narcissistic personality disorder

NPD is considered to result from a person's belief that he or she is flawed in a way that makes the person fundamentally unacceptable to others [5]. This belief is held below the person's conscious awareness; such a person would typically deny thinking such a thing, if questioned. In order to protect themselves against the intolerably painful rejection and isolation that (they imagine) would follow if others recognised their supposedly defective nature, such people make strong attempts to control others’ view of them and behaviour towards them.

also common in teenagers and by no means necessarily a personality disorder, (unless you're still acting like that when you're 37...)87.102.86.73 (talk) 15:31, 27 July 2008 (UTC)

g-force

From my calculations I figured this out:

333 m/s (334)
333 * 60 (334 * 60) = 19,890 (20,040) m/min
19,890 * 60 (20,040 * 60) = 1,193,400 (1,202,400) m/hr
1,193,400 / 1,000 (1,202,400 / 1,000) = 1,193.4 (1,202.4) km/h

741.5443808156358 (747.1367215457689) mi/h

I want to figure out the g-force for the above mentioned data, I looked over the g-force article, but couldn't figure out how to get the value. 76.29.116.172 (talk) 02:34, 27 July 2008 (UTC)

g-force measures acceleration, the rate of change in velocity. It is impossible to calculate acceleration unless, in addition to the velocity you gave, you have the time in which it was attained. --Bowlhover (talk) 03:29, 27 July 2008 (UTC)

yup. it doesn't matter how fast you're going: if you're going 741 mi/h but at a constant speed, then you're going 0 g's. Out of curiosity, where did you pull your original velocity from? --Shaggorama (talk) 04:03, 27 July 2008 (UTC)

At a guess, the speed of sound at sea level. —Preceding unsigned comment added by 121.72.174.226 (talk) 04:19, 27 July 2008 (UTC)

Just as an example, say it takes you exactly one minute (I completely random number that I pulled out of my ass) to accelarate to Mach 1, the speed of sound in air. The acceleration is then 333 m/s divided by 60 s, which is 5.55 m/s^2. Since the earth's gravitational acceleration is about 9.8 m/s^2, this accelration would give about half a g-force. ADFSGL (talk) 10:36, 27 July 2008 (UTC)

Removal of spleen, lymphnode and thymus

What are the effects of removal of spleen, lymphnode and thymus in new borns? —Preceding unsigned comment added by 59.92.122.159 (talk) 04:28, 27 July 2008 (UTC)

A weak immune system, at the very least. Have you read spleen, lymph node, thymus? --Ayacop (talk) 06:00, 27 July 2008 (UTC)

In addition to that, the lympathic system will also get weakened. You should know that spleen acts as a blood-reservoir. In case of emergency, such as excessive bleeding, spleen releases its extra blood for replenishing the loss. If the spleen is removed, this mechanism will not work. In addition to that, spleen produces new leucocytes in new borns. So, the leucocyte no. in their bodies will also fall, making them more prone to pathogens. If we remove the thymus, some thymus related hormones will not be formed in the later age. For the removal of lymphnodes, the deamination rate in the liver may decrease.117.201.97.83 (talk) 18:40, 27 July 2008 (UTC)

We have an article specifically on asplenia, the condition of being without a spleen. -- Coneslayer (talk) 16:58, 28 July 2008 (UTC)

"the button"

What is the physiology behind the syncope that often results from a strong punch to the jaw or chin? --Shaggorama (talk) 04:38, 27 July 2008 (UTC)

Head gets punched, head snaps backwards, brain bangs against back wall of skull, brain doesn't like this, brain goes bye-bye for a while. I think. --Kurt Shaped Box (talk) 07:40, 27 July 2008 (UTC)

Due to inertia it first bangs against the front, after gaining momentum it bangs against the back. Then it may wobble around a bit, but by then you are likely to have lost a few of your wits. Traumatic brain injury has some data on this. --Cookatoo.ergo.ZooM (talk) 11:20, 27 July 2008 (UTC)

Then what's so special about the chin? There are loads of ways to get hit in the face, but for some reason getting a solid knock right on the kisser seems to make people's knees more rubbery than other spots on the head. Besides, I don't think all KO's are concusions, otherwise we'd be seeing alot more permanent brain damage cropping up faster from boxers. I'd heard some rumor that the mandibular nerve has something to do with it (hence having a solid chin helps counter this effect because the nerve doesn't get stimulated when the button is "pushed"), but I don't know what that's all about. --Shaggorama (talk) 15:51, 27 July 2008 (UTC)

Could it be because the chin is further away from the brain and is forward of the neck so you get more leverage? If you hit someone above the ear, say, their head will just move sideways, you hit them in the chin and it rotates as well. --Tango (talk) 17:27, 27 July 2008 (UTC)

My father was a professional boxer at one time and he said that to knock someone out you have to hit them on the side of the head and make the head whip round. SpinningSpark 17:36, 27 July 2008 (UTC)

I remember a show (probably the Discovery Channel) that discussed the "side of the head" vs. "face" angle in boxing and car crashes. They said it had something to do with the hemispheres of the brain spreading apart due to a blow to the side of the head. This would cause the connecting tissues (axon?) between the hemispheres to swell up, causing passing out, or worse, coma and death. I suppose hitting on the side of the chin might be worse as it is farther away, as Tango said, increasing torque. --Bennybp (talk) 18:45, 27 July 2008 (UTC)

I think the tissue you meant is the Corpus callosum. I still don't believe that getting KOed means you necessarily underwent brain trauma (not that it's great for the brain), although there certainly seems to be some consensus here. Speaking of the temporal vs facial angle, I also read that a blow to the temple can take a person down because it disrupts the equilibrioception of the semicircular canals. Thoughts? --Shaggorama (talk) 19:59, 27 July 2008 (UTC)

I think I found what I was talking about: Diffuse axonal injury (although not necessarily about spreading of the hemispheres, it's close). When not a direct hit (ie a hit on the chin, causing rotation, etc) it can sometimes cause more damage. --Bennybp (talk) 23:50, 27 July 2008 (UTC)

There's also the Glass Jaw. Julia Rossi (talk) 00:53, 28 July 2008 (UTC)

Is Purell safe to drink?

Everyone's sort of paranoid about security where I live right now; I've seen security guards ask people to take a drink of every liquid they're carrying to make sure they're not trying to bring harmful chemicals into museums and stuff. My question is: if someone had to drink some Purell for security reasons, would it be safe, and how much would be the maximum amount someone could drink safely? Thanks in advance. —Preceding unsigned comment added by 58.35.41.223 (talk) 11:14, 27 July 2008 (UTC)

"if someone had to drink some Purell for security reasons" ?? what?

No it's not safe to drink in general it's amongst other things 62% alcohol - that's almost twice that of vodka.87.102.86.73 (talk) 11:25, 27 July 2008 (UTC)

Heh, like I said, people here are crazy. —Preceding unsigned comment added by 58.35.41.223 (talk) 11:29, 27 July 2008 (UTC)

Well, that alcohol content certainly wouldn't make it unsafe to drink, it just means it gets you drunk pretty easily. Looking at the article, there doesn't seem to be anything particularly toxic in Purell. That doesn't mean it's good for you, but taking a sip of it wouldn't do you any actual harm. Presuming, of course, that the article lists the ingredients correctly, which may or may not be the case. (That said, the bit about the maximum amount someone could drink safely kind of activates my "suspicious bastard" cycle and makes me wonder if the part about museum guards and whatnot is made up and you'd just like to use Purell as a substitute for an actual alcoholic beverage, perhaps because those bastards at the store want to see some proof of age. Should this be the case, I'd recommend against it. Not only is it not made for drinking and probably isn't good for you, it's downright pathetic. I mean, we're talking bum pathetic; that's like one step away from drinking anti-freeze. It's just a dumb idea.) -- Captain Disdain (talk) 12:49, 27 July 2008 (UTC)

The maximum amount part does seem funny. Why does it matter what the maximum amount you can drink is. All that matters is whether you can drink the small amount a security guard is likely to request of you. Nil Einne (talk) 15:23, 27 July 2008 (UTC)

I think the security guard would not let you take it in, or a bottle of wine, or crate of beer either.. They tend to discourage museums being used as a drinking pit in general...87.102.86.73 (talk) 15:25, 27 July 2008 (UTC)

Given that the manufacturers of Purell themselves advise against its ingestion, I think you have good grounds to tell this security guard he can drink it himself if he wants. This is really strange. Even airport TSA guards don't make you drink your liquids, nor do guards at the Smithsonian. What museum is doing this? --Shaggorama (talk) 15:56, 27 July 2008 (UTC)

Nothing to do with museums, I know, but I've definitely heard of it happening on some train networks when there's a security alert. 91.143.188.103 (talk) 18:36, 27 July 2008 (UTC)

I've heard it happening with security in airports too at least in the immediate post 2006 transatlantic aircraft plot world. I suspect any security in such a world won't allow you to bring in anything with that high a alcohol content anyway. See [2] for example which suggests in 2006 when the liquid ban in the US was initially relaxed liquor still had to be checked-in. I don't know what conditions are like now but again, I suspect if anyone is that paranoid about liquids whether in airports, museums or train stations, they're not going to allow anything with a 62% alcohol content no matter whether you drink it or not. For that matter, I doubt any security guard is going to ask you to open your bottle of liquor or any other alcoholic beverage and take a sip so I would suspect they're automatically out. If they are going to ask you to drink all liquids, Purell is likely to go with them simply because no security guard is likely to ask you to drink it and if that's their only option, they'll just ask you to chuck it... (Indeed I suspect if you did volunteer to drink Purell the guards would be even more concerned) Nil Einne (talk) 18:55, 27 July 2008 (UTC)

I remember when the only liquids you were allowed on planes were things like baby's milk they made you take a sip. The only reason for requiring people to take a sip of any liquid is if you want to verify the liquid is a drink. Purell is not a drink, so it's a pretty pointless test. --Tango (talk) 19:15, 27 July 2008 (UTC)

Forgive my lateness, but doesn't Purell contain toxic *denatured* alcohol? --70.167.58.6 (talk) 22:31, 27 July 2008 (UTC)

Makes no difference, god bless them! -hydnjo talk 23:42, 27 July 2008 (UTC)

Why would a product like that be misleadingly named Purell? It sounds like spring water - unless it's pronounced pure-'ell. Julia Rossi (talk) 03:24, 28 July 2008 (UTC)

That is how it's pronounced by everyone who I've heard say its name. --M1ss1ontomars2k4 (talk) 03:27, 2 August 2008 (UTC)

there's actually a problem in prisons with people drinking hand sanitizer. http://www.webmd.com/content/article/131/118125.htm hey everybody, purell coladas!Gzuckier (talk) 03:47, 28 July 2008 (UTC)

Hmm, interesting. The OP appears to be in China. If this is the case, then it might make his story slightly more plausible.--Anakata (talk) 09:53, 28 July 2008 (UTC)

Funny story. I was traveling with a swim team several years ago and the airport security guards made one of my team mates take a drink from the bottle he was carrying, but this joker had a water bottle full of 151 proof vodka. He did a great job of drinking deeply, smiling politely, walking away quickly, and vomiting in the bathroom. Plasticup ^T/C 12:26, 28 July 2008 (UTC)

Guys, this is quite simple. Isopropyl alcohol (rubbing alcohol) is mentioned in the ingredients. On top of that, the label clearly says to contact a Poison Control Center if ingested. If that's not enough to convince you guys it's not safe I dunno what is. --M1ss1ontomars2k4 (talk) 03:27, 2 August 2008 (UTC)

Suicide thoughts sympton or illness

Are suicide thoughts always a sympton of an illness (like depression) or can they be a illness on their own? —Preceding unsigned comment added by Mr.K. (talk • contribs) 17:28, 27 July 2008 (UTC)

Question moved from:http://en.wikipedia.org/wiki/Wikipedia:Reference_desk/Miscellaneous#Suicide_thoughts_sympton_or_illness

Suicide crisis says it is usually caused by depression or some other psychiatric illness, I don't know if it always is. It's probably just a matter of definition. If you or someone you know is having suicidal thoughts, there are phonelines you can call for advise (I don't know where you are, so I don't know any specific ones). They'll be more help than us. --Tango (talk) 19:19, 27 July 2008 (UTC)

Foam on the beach

If I find some foam/spum on the beach, floating everywhere, kind of green/brown, what is it supposed to be? —Preceding unsigned comment added by Mr.K. (talk • contribs) 17:41, 27 July 2008 (UTC)

Take saltwater. Add various proteins. Swish it up. You'll get foam. If it comes out of the sea, it is called sea foam. -- kainaw™ 19:51, 27 July 2008 (UTC)

Oooh! Here's a nice picture. -hydnjo talk 23:36, 27 July 2008 (UTC)

It's extraordinary and beautiful with every bubble about to give birth to a human! Julia Rossi (talk) 00:44, 28 July 2008 (UTC)

And, every human is ... a photographer!  ;-) hydnjo talk 00:51, 28 July 2008 (UTC)

Is it me, or is every human a photograph in a space suit? --Tango (talk) 01:43, 28 July 2008 (UTC)

ET alert. It gives "pond life" another illustration. Julia Rossi (talk) 03:10, 28 July 2008 (UTC)

And the reason why salt water does this and plain water doesn't (so why you get seafoam and not riverfoam) is to do with ions and some ionic behaviour that, rather excitingly, was only really noticed a few years ago. That salt water foams was obviously noticed ages ago, but it's only recently that we've got close to understanding why. Even in apparently simple areas, there is still a lot to be studied :D 79.66.124.253 (talk) 20:48, 28 July 2008 (UTC)

Collection of gas over water

If one collects a gas, say hydrogen gas, over water, I know that one must subtract a constant based on the temperature to find the pressure of the gas to account for the water vapor present. What if the same operation is performed over a solution? For example, if you react perchloric acid solution and magnesium, producing magnesium perchlorate and hydrogen gas, and collect the hydrogen gas, do you have to factor in the water vapor coming off from the solution in determining the pressure, and hence the molarity or mass of hydrogen? FlamingSilmaril (talk) 20:04, 27 July 2008 (UTC)

Yup, you still need to account for vapor pressure. The vapor pressure of a solvent over a solution will always be less than the solvent as a pure liquid, but its' still there. Use Raoult's law. BUT, in the specific example you gave, if you use an excess of acid, the magnesium should react completely allowing you to produce a good estimate of the mass of product by using stoichiometry. This all mainly depends on how accurate you need to be and whether we're talking ideals on paper or laboratory products. --Shaggorama (talk) 20:23, 27 July 2008 (UTC)

Actually, it's dealing with an excess of magnesium. What we're given is: you react a certain volume of the perchloric acid solution and excess magnesium, and a certain volume of gas is produced at a certain temp and pressure. Then you have to find the molarity of the solution. I'm fairly sure I know how to do it; I was just wondering whether the vapor would be a factor. And this is all on paper, not actually in the lab. Thanks very much! FlamingSilmaril (talk) 20:45, 27 July 2008 (UTC)

Wow, i can't believe I gave you teh wrong limiting reagent! Thanks for the correction, I've gotta stop doing this tired... I haven't done the math yet myself, but my guess is that the vapor pressure will be a very small contributor to the product. If you're actually given the temperature and pressure of the gas produced, then I would suggest assuming that the vapor pressure contribution is negligible: find theoretical moles of hydrogen produced via stoichiometry, then compare the pressure given by PV = nRT with the experimental pressure given by the problem. It's an estimate, sure, but if it matches up, you're set; if not then backtrack to considering vapor pressure. --Shaggorama (talk) 07:47, 28 July 2008 (UTC)

Information!

Can anyone suggest me a link from which I can download all Scientific Laws, effects and principles in one complete .pdf or .doc form?117.201.97.83 (talk) 20:49, 27 July 2008 (UTC)

ALL? -hydnjo talk 23:27, 27 July 2008 (UTC)

That's what the OP said. I don't think we're going to be able to help with this one. Algebraist 23:29, 27 July 2008 (UTC)

How about $R_{ab}-{1 \over 2}Rg_{ab}={8\pi }T_{ab}-\Lambda g_{ab}$

${\frac {\partial \langle H\rangle }{\partial \pi _{n}}}={\frac {\partial a_{n}}{\partial t}}\quad ,\quad {\frac {\partial \langle H\rangle }{\partial a_{n}}}=-{\frac {\partial \pi _{n}}{\partial t}}$

and the QM Hamiltonian (anyone know it?). *Max* (talk) 03:04, 28 July 2008 (UTC).

I was going to suggest downloading Science for Dummies from the library shelf, but I changed my mind. Julia Rossi (talk) 03:21, 28 July 2008 (UTC)

I can't imagine you would find them all in one place. Try starting with our laws of science and physical law articles.--Shantavira|^{feed me} 06:24, 28 July 2008 (UTC)

More than half of those are approximations and the rest can be derived from my four. *Max* (talk) 15:04, 28 July 2008 (UTC)

New surgical procedure

A female doctor from Michigan devised and conducted a new heart repair surgical procedure (along with a team of other surgeons) on a man about 26 years old who resided in San Diego. The surgery was performed sometime in November 2007. It was even rumored that the new procedure might be named after her. Does anyone out there know the name of this doctor and the name and/or type of procedure she performed?

71.191.91.20 (talk) 21:02, 27 July 2008 (UTC)

Quality of medical reliable sources

I am wondering how to evaluate the quality (reliability, impact factor) of medical sources when using them as references on Wikipedia. Since I am not experienced in reading or evaluating studies directly, my focus is more on articles that interpret study results. I would like to learn how to research the journal and the author(s).

Specific journals:

• Emergency Medicine News, indexed/distributed online by Lippincott Williams & Wilkins
• Canadian Medical Association Journal, prestigious, but recent decline mentioned at Talk:Canadian Medical Association Journal

Thanks. Flatscan (talk) 22:26, 27 July 2008 (UTC)

Let me get this straight; are you asking us on the Reference desk how you should evaluate the references that you may find in articles relating to medicine. Is that your question? -hydnjo talk 22:53, 27 July 2008 (UTC)

That's about right, although these references may not be in the Wikipedia article yet – I would be considering whether to add them and how to present them. Would Wikipedia:WikiProject Medicine be a better place for this question, or would you suggest another place? Flatscan (talk) 23:07, 27 July 2008 (UTC)

Before asking elsewhere please read and understand our article about citing sources. -hydnjo talk 23:26, 27 July 2008 (UTC)

Thank you for the link. I navigated through Wikipedia:Scientific citation guidelines to Wikipedia:Manual of Style (medicine-related articles)#Citing medical sources and Wikipedia:WikiProject Medicine/Reliable sources. CMAJ is listed there as a core journal. Flatscan (talk) 23:52, 27 July 2008 (UTC)

For all of that, "You're a better man than I am..."! -hydnjo talk 00:00, 28 July 2008 (UTC)