Wikipedia:Reference desk/Science

Reference Desk

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particles are always in what

Please clarify your question. What, exactly, do you want to know? --Ashenai (talk) 22:30, 4 October 2005 (UTC)

Maybe it's a riddle...? -- SCZenz 00:47, 5 October 2005 (UTC)

constant motion?--Michael 04:28, 9 October 2005 (UTC)

Heroin in Food

I know this sounds crazy,but I NEED to know EVERYTHING that happens to the human body,if you EAT heroin.I have even gone on sites in New Zeland and Austrlia trying to find the answer to this ?.I have found nothing anywhere!I want to know how it breaks down chemically,amounts in blood verses stomach contents,morphine to 6MAM,how long it takes to die.I think you get it.Thank-You for ANY answers you can give me. Toni I'm sorry!I did not mean to send this twice.Until my daughter died I,I wasn't even sure how to turn one on.

Search medline for heroin overdose like this [1]. You get hundreds of hits. You will have to sift for those that might describe oral overdose, like this PMID 10829332. Look at its bibliography for previously published articles on oral overdose. What you really want is something that describes the characteristic effects of oral OD vs injected OD because the latter is hundreds of times more common. Alternatively, go to a medical school library and ask for some toxicology and drug abuse texts. Look at the references to their chapters. I assume you are not dealing with an oral OD at this minute? If so, get him to the ER. alteripse 23:41, 4 October 2005 (UTC)

One warning - medical journals are written for doctors and scientists to communicate with each other, and consequently they assume a *lot* of background knowledge that doctors or biological scientists receive as part of their college training. It may take you some time and a fair bit of reading to familiarise yourself with the relevant background (though the Wikipedia is a reasonably good place to get a lot of that background), but it's by no means impossible. Many articles will also use some statistics, so you may need to learn a bit about that. Good luck, and I hope you find what you are looking for, whatever that is. --Robert Merkel 01:01, 5 October 2005 (UTC)

If you eat heroin, it will be absorbed either as heroin itself or as morphine (some heroin breaks down to morphine in the stomach). What happens depends on the dose and the individual. The opiates will be absorbed slower than if the were injected, but the total length of time that the patient is exposed will be longer. Physchim62 15:29, 7 October 2005 (UTC)

Would inducing vomiting be a good idea? --03:21, 13 October 2005 (UTC)

Itunes Problem

I have a bit of an interesting situation regarding iTunes. I am attempting to share my music so that a friend can access it. However, we seem to be on different subnets, despite the fact that we are using the same ethernet jack to access the internet. Would it make a difference that I intially installed and started intunes using a different ethernet jack across campus? The initial network setup was also done across campus, perhaps if I change my subnet this will solve the problem? Thanks for any suggestions!

How exactly are you using the "same" ethernet jack to access the internet? iTunes isn't designed to work via the internet anyway; rather, it's designed to work over local networks, so if you are both using the same router or something like that, things should be hunky-dory. Also, what are the models and capabilities of the computers you are using? Are they AirPort/802.11 capable? Garrett Albright 17:08, 5 October 2005 (UTC)

Poliosis / White Forelock

Hi This is not really a question but more of a request. I have performed some google searches to find a name for my husband's white tuft of hair above his forehead. I found Poliosis and White Forelock. I also found a list of dreadful diseases of which I'm fairly certain he has none. I then tried to find any information possible on Wikipedia and the search came up with zero. I'm just wondering if there are any personality traits (like extreme intelligence or other endowment) that might accompany this somewhat less common physical characteristic. I'd love it if anyone in-the-know could add this subject to your website.

thanks

There are many minor genetic physical traits that can occur by themselves or with several other physical anomalies. When they occur by themselves they have no hidden significance and cause no problems. When they occur with multiple other anomalies, some of those other problems can turn out to cause serious trouble. This combination of anomalies is usually referred to as a congenital syndrome. Other examples of minor physical anomalies that can be of no significance by themselves or can occur as part of a more serious syndrome are little pits in front of the ears, short broad thumbs or fingers, high-arched palate, and indented chest. Finally, there are no personality traits associated with this type of minor isolated anomaly because the only body part affected is that area of the scalp. alteripse 01:44, 5 October 2005 (UTC)

You can get a tuft of white hair by being scared shitless. Someone in my family once got that after she had fallen between railway tracks and had a train run over her. She was otherwise unharmed, but you can imagine her state of mind at the moment. But now I wonder how such a thing can happen. Does all the pigment get sucked out of the hair? And how does a scare cause that? DirkvdM 12:53, 6 October 2005 (UTC)

Having the pigment "sucked out" of hairs is as likely as having a sudden fright turn your nail polish from red to blue. Hairs already extruded from the hair follicles do not change color unless dyed, bleached, or oxidized. alteripse 03:16, 7 October 2005 (UTC)

I agree that the color of existing hair won't change due to stress, but having a localized loss of pigment in future hair due to a stressful episode isn't impossible. I don't know if any studies have been done on this, but I can easily imagine that stress hormones like adrenalin could interact with pigment cells and cause them to shut down. Other causes could be genetic or environmental, such as Sun-bleaching (which actually could destroy the pigment in existing hair). StuRat 06:32, 9 October 2005 (UTC)

math

If you know the year month and date a person was born how can you quickly tell them what day their birthday will fall on this year? With no help from a calender thanks.

See Calculating the day of the week.-gadfium 03:47, 5 October 2005 (UTC)

ABOUT BULLSEYE NETWORK VIRUS

When I use Internet Explorer, suddenly, a pop-up opens with the heading 'BULLSEYE NETWORK'. This pop-up appears when I open any website! Is that a virus that has attacked my computer or my Internet explorer? What should I do to get rid of that? Can anyone tell me more about this Virus?

You have aquired a piece of adware. This is not technically a virus, but is almost certainly software you don't want on your computer. It is designed to be difficult to remove. I recommend you get a copy of Ad-Aware or any of its competitors and run it on your computer. The following Symantec page may be useful to you: [2].

To prevent such infections in the future, please consider using a different browser, either Firefox or Opera. Internet Explorer is particularly prone to such infections.-gadfium 03:42, 5 October 2005 (UTC)

Or better still, switch to Linux. That should shield you a whole lot more against viruses and the like. DirkvdM 12:55, 6 October 2005 (UTC)

Linux Lover 69.181.206.232 04:21, 10 October 2005 (UTC)

Well, nothing wrong with that, is there? DirkvdM 18:16, 11 October 2005 (UTC)

If you switch to Linux, then there are still companies openly trying to abuse your computer for malicious reasons and not facing any consequences for it (even if it doesn't affect linux users much), so I suppose you could say it hasn't solved the problem. (and might even still be a problem if they find a vulnerability in some Free Software, or trick a linux user into installing their software). I'd take 69.181.206.232's comment as a compliment though... Ojw 18:35, 14 October 2005 (UTC)

maths

Try starting in Mathematics --Borbrav 04:05, 5 October 2005 (UTC)

Random vector member?

In the standard template library for C++, is there any trivial way to get a random member of a vector (or map) safely? - RedWordSmith 04:57, 5 October 2005 (UTC)

If I remember correctly (and I may not), isn't access to a random member of a vector O(1)? I believe vectors aren't linked list-backed types. Or is what you ask in the "safely" part? If so, what do you mean? Dysprosia 09:07, 5 October 2005 (UTC)

User:RedWordSmith wants to choose a random element and to access it with a single command. I don't think that is possible. Masatran 10:37, 5 October 2005 (UTC)

Yes, exactly. Any ideas on what the best way to do this using multiple commands? I've thought about shuffling the entire vector somehow a couple times and then taking an element from the top, but that can't be efficent no matter how it's done. - RedWordSmith 20:57, 5 October 2005 (UTC)

C++ vectors are random access, implying O(1) access, thus these are most likely not linked-list like types. What is wrong with using operator[] on the vector? Dysprosia 22:47, 5 October 2005 (UTC)

Maybe I'm missing something here, but wouldn't the following three step process work:

1. Find out the number of elements $l$ in the vector (my C++ is very rusty, but isn't that the length method of the vector class)?
2. Generate a random number $i,0\leq i<l$ with a pseudo-random number generator.
3. Access the i'th object in the vector (either with operator[] or the at method, which is range-checked.

The choice of which pseudorandom number generator to use depends on your application. If, for some reason, it is important that an attacker not be able to predict which element will be selected next based on the elements selected previously, you need a cryptographically secure pseudo-random number generator, otherwise any modern generator, including the one in your system library, will probably do (though I prefer to use the Mersenne twister for all my own simulation work because it's both good and fast).

If you want a guarantee that you won't get repeated elements, then a shuffle is probably the best way to go. But here's a basic performance tip; if your objects are large, create a vector/array of pointers to them and shuffle the pointer array rather than the objects themselves.

As to the interface, surely you could define a subclass of vector which adds a "ranelement" method that implements the procedure I've described above? --Robert Merkel 01:00, 6 October 2005 (UTC)

OH. I get it now. Red wants to access an element at random. Yes, that solution is the one that first comes to mind. I don't think there's a simpler method... Dysprosia 09:31, 6 October 2005 (UTC)

Thanks, I'll give it a try. For some reason I was under the impression that the element choosen by the random number generator might not exist; I guess I'm just too used to plain C. I think I also got thrown off track reading about nonstandard methods to get random samples at one point. - RedWordSmith 00:06, 7 October 2005 (UTC)

Mod it with l if your RNG doesn't do generation within a certain range. Dysprosia 10:27, 7 October 2005 (UTC)

Anabolism and lifespan

Does a moderate level of body building and the associated muscle mass gain cause a decrease in life span? Lets assume that the person doing the body building and undergoing anabolism has a normal BMI and average build (that is, they are not overweight or underweight). Also assume that there are no steroids or supplements involved - only a small increase in protein rich foods being consumed. 205.188.117.71 04:59, 5 October 2005 (UTC)

No evidence is available for your specific question because such changes are never done in isolation from other factors that might change lifespan: healthier eating (e.g., reduced fat intake), reduction of unhealthy exposures (e.g., less time with secondhand smoke), etc. There is some evidence that in small mammals those who are allowed to eat less calories daily over most of their lifespan live a bit longer; this appears to be a phenomenon distinct from simple avoidance of obesity but we have no way to extrapolate this to people or to know exactly what the mechanism is. This topic of changing life span by changing daily living habits or eating habits is generally referred to as life extension and much has been published online and in the scientific literature but the quality ranges widely and much of what has been written about people is speculation, opinion, or marketing written to sell a product. Be skeptical. alteripse 10:36, 5 October 2005 (UTC)

The trick to a long life is to metabolize slowly. Like my turtle which I expect to out live me by about 100 years. I metabolize quickly because I like to have fun...unlike my turtle who just sits in the sun all day.--Eye 20:13, 5 October 2005 (UTC)

• Our Caloric restriction article is worth looking at as well. Capitalistroadster 04:55, 7 October 2005 (UTC)

Graying Hair

Why does hair turn gray or white as humans age?

• Our Hair article states: "Older people tend to develop gray hair (actually colorless) because the pigmentation in the hair gets lost and the hair becomes colorless. The age at which this occurs varies from person to person, but in general nearly everyone 75 years or older has gray hair, and in general men tend to become gray at younger ages than women." Capitalistroadster 07:19, 5 October 2005 (UTC)
  • This answer is perilously close to Moliere's explanation that a sleeping potion worked "because of its dormitive properties." I am not sure how clearly we understand the process by which hair follicles stop having pigment. Is pigment generated by intracellular processes that are programmed to stop at a certain age? Are there separate cells at the base of hair follicles that add the pigment to a growing hair? What is the difference between hair follicle cells that grow a pigmented hair versus a non-pigmented hair? Are these hormone-dependent changes like puberty or menopause-- if so we have surprisingly little understanding of this type of change in early or middle adult life. Are these specific genetic responses to a certain duration and level of hormone exposure, like male pattern baldness? Interesting question. Anyone want to research an article on hair color? alteripse 10:52, 5 October 2005 (UTC) Well, guess what, the answer was already in our article:

The change in hair color is caused by the gradual decrease of pigmentation that occurs when melanin ceases to be produced in the hair root, and new hairs grow in without pigment. Two genes appear to be responsible for the process of greying, Bcl2 and Mitf. The stem cells at the base of hair follicles are responsible for producing melanocytes, the cells that produce and store pigment in hair and skin. The death of the melanocyte stem cells cause hair to begin going grey. (Nishimura, et al., 2005)

Perhaps you didn't mean to get into the technical details of how pigmentation stops being produced, but were rather asking why, what evolutionary purpose does gray and white hair serve ? It may be that it serves no purpose, and is just a malfunction that isn't very harmful, so isn't selected very strongly againt. Another possibility is that visual age markers, like gray hair and wrinkles, are in some way helpful to the species. On the positive side, they may be ways to identify older people, who presumably have valuable knowledge and experience to offer, which may help the group survive. A more negative interpretation may be that this helps to identify people who are beyond their ideal fertility age, and thus should be avoided for younger more fertile mates. If either of these is a benefit to marking older people with gray and white hair, then evolution may actually select for this feature. Note that many other mammals share this trait with humans. StuRat 06:20, 9 October 2005 (UTC)

thrust agumentation

why a water nozzle is having a greater reaction when it is faced by a rigid wall very close to it rather than when it is faced in free air. --202.137.218.75 07:51, 5 October 2005 (UTC)Abhishek gupta, India
(formatted question and removed email - Mgm|^(talk) 09:52, 5 October 2005 (UTC))

Newton's third law? Dysprosia 10:30, 5 October 2005 (UTC)

You didn't say if the wall was right up against it or just close. When the nozzle is pressed right up against the wall the water can't get out as easily and allows the pressure to build up. This is also why a nozzle causes greater reaction, than when water comes straight out the end of the hose.

Dysprosia is correct. When in the open air, the water pushes air out of the way, as the air can freely compress and move. As you approach the wall (which presumably does not compress or move), the water exerts a force on the wall, and the wall effects a reciprocal force on the water. At distance, the water tends to splatter into the air (per the initial condition). As the nozzle gets closer, more of the wall→water force is directed back toward the hose. Since water isn't compressible, this force transmits into the hose collectively. When the nozzle is directly adjacent to the wall, virtually all of the force affects the hose. — Lomn | Talk / RfC 14:36, 5 October 2005 (UTC)

Stabilizing the frequency of vibrations in a quartz crystal used in an oscillator circuit

Dear Wikipedia Volunteer, I am currently undertaking a research project. For this to be successful, it is important for me to know how to stabilize the frequency of vibrations of the quartz crystal used in an oscillator circuit. The quartz crystal in question is a 14.3183 MHz oscillator, but the output frequency is accurate only till 14.31 MHz (i.e. about 10 kHz). How can I stabilize the vibrations so as to get accurate output frequency in the order of tens of Hz? I would be highly obliged if you kindly post the answer to my query at your earliest convenience, or give me a few references in this regard. Thanking you, Yours sincerely, Saikat Das (removed e-mail address)

Saikat, I don't know the details of your project, but if the crucial thing is that you need a high-precision clock signal, would something like [these] do the job? I found this by googling "precision oscillator"; lots of other relevant links turned up. --Robert Merkel 15:18, 5 October 2005 (UTC)

OpenDocument XML editor wanted

Is there any OpenDocument editor that can edit the XML elements directly? —Masatran 11:10, 5 October 2005 (UTC)

If I'm not mistaken you can do that with any simple editor. At least that's the way to do it with html. Or do I misunderstand your question? DirkvdM 13:01, 6 October 2005 (UTC)

List of text editors and XML#XML Editors. The problem is, that I don't think OpenOffice, KWord, etc. like to edit OGW as a set of textfiles, they prefer to interpret it. Ojw 13:41, 9 October 2005 (UTC)

Dance Pads Sales

Hello dear friends, Does anybody know how many dance pads (in units) are sold annually in the USA by manufacturer? Thank you Sincerely

Are you referring to Dance Dance Revolution pads? -Haon 00:02, 11 October 2005 (UTC)

Individual Generators and natural disasters

how long do individual generators last? Can generators communications be affected in natural disasters? should we be investing in new research to develop cheaper and better generators? Is the Department of Homeland Security in the US preparing for wide scale, long term power outages?

• Generators are more fuel-dependant than breakdown-prone, though such breakdowns can occur. On the whole, it depends entirely on the stockpiled fuel supply.
• I have no idea what generator communications are. Could you elaborate?
• Probably not. Again, fuel source is the main concern (and I'd consider a cold fusion generator more a problem of cold fusion research than generator research)
• I don't think there's any way the U.S. at large can prepare for wide scale long term loss of power. Check out some apocalyptic fiction (Alas, Babylon and Lucifer's Hammer are good examples) for thoughts on what such widespread devastation would mean for modern first-world society. In a nutshell, if a disaster of such magnitude strikes, basic survival will be far more important than maintaining the power grid. That said, reducing the dependancy on imported oil would alleviate a major choke point for the fuel supply. Nuclear energy (the most modular major power source) has been overwhelmingly unpopular since Three Mile Island and Chernobyl, however. — Lomn | Talk / RfC 14:27, 5 October 2005 (UTC)

Generators will last as long as there is fuel for them and they stay in good working order. I presume you mean emergency type generators like you might find in the hardware store. There is ongoing research to find new ways to produce power (like fusion or solar power) but my opinion is the generators we have are just about as good as they can be expected to get without a technological advance.

As far as your question about whether "Homeland Security" is prepared for anything except re-electing republicans, I think we got a pretty clear answer last month. alteripse 15:08, 5 October 2005 (UTC)

To quote someone or other - "There is a major disjoint between people who think national security means keeping the nation safe, and those who think it means blowing shit up." Shimgray | talk | 20:04, 5 October 2005 (UTC)

Photosynthesis

Give an example of an experiment to find if photosynthesis has taken place inside a leaf.

Please answer this question now beacause I have a test and I could not understand this question. Thank you

You could read photosynthesis, but we're not really in the business of doing other peoples' homework here. -- SCZenz 16:13, 5 October 2005 (UTC)

I'm feeling nice, so I'll give you a hint.... What is a product of photosynthesis that you can test for? -(Fang)

You mean like electrons? David D. (Talk) 22:23, 5 October 2005 (UTC)

Electrons are not a product of photosynthesis. Imagine photosynthesis as an equation. What does photosynthesis produce? --Fastfission 17:00, 6 October 2005 (UTC)

2H20 + light (4 photons) --> O2 + 4H+ + 4e- is the first step of photosynthesis. Also known as the light reactions. I was trying to give a clue, although I admit it was somewhat cryptic. The traditional equation for photosynthesis ( 6CO2 + 6H20 + light --> 3O2 + glucose) is very misleading since it does not recognise that there are several independent reaction associated with carbon fixation. The first step does not involve the fixation of carbon it is all about converting light energy into chemical energy. The reduction of NADP to NADPH using the reducing potential of the electrons. As well as ATP from the movment of the electrons through the electron transport chain in the thylakoid membrane. David D. (Talk) 17:25, 6 October 2005 (UTC)

Heroin

What happened to my ? on heroin when eaten in food? Thanks, Toni

We answered it. Read more closely above. alteripse 15:06, 5 October 2005 (UTC)

Internet Statistics

I am attempting to find some internet statistics:

1. How many people currently use Windows 98 vs. Windows XP?
2. How many people have dial-up vs. broadband?
3. How many people have an 800 X 600 monitor vs. 1024 X 768 or larger?

Thanks,
<removed e-mail address>

• I'm not sure about the numbers, but if you want to know this because of some design job, I recommend you design with the Windows 98 dial-up 800x600 users in mind (at the very keast offer a low-bandwidth option for them). There's nothing more annoying than site, images or programs that are not designed for your system. - Mgm|^(talk) 20:57, 5 October 2005 (UTC)

w3 publishes this info here: http://www.w3schools.com/browsers/browsers_stats.asp Boneyard 12:31, 11 October 2005 (UTC)

different question

If you buy stock in companies that sell this stuff, then you get their annual reports which have actual numbers of how many got sold that year. Some companies make their annual reports available to non-shareholders. So then you need to get them for every year since the products that interest you came out.

There are also places that have already done this kind of research and published the results, Gartner Research for example ... use Google or some other search engine (there are scores if not hundreds to choose from) to find places that do Research, then search them for the kind of research reports you interested in ... I think Gartner Magic Squares would be very close to what you looking for.

Gartner Magic Squares are charts of various types of products within some industry ... one dimension is all the stuff the products can do, another dimension is degree of market share the market leaders have, yet another thing shown is how good the stuff is relative to each other, with various vendors products plotted on this thing, accompanied by an article that goes into details about what is plotted on the graph.

AlMac|^(talk) 15:27, 8 October 2005 (UTC)

How do plants and trees live in islands where their roots are in sea water?

Hello everybody,

I have always been wondering while seeing some nature tv programs or photos or etc that how come trees are able to live in such conditions as in islands where the soil is ssandy and permeable to sea water and these trees most probably have roots that are soaked in salty sea water. Apart from the fact that many trees, as far as I know, could not stand the salt in the sea water, their roots are also not able to breath oxygen, could they? As you see in many commersial photos or educational tv products there are islands where their jungles are only a few meters away from the sea water. How is that?

So please let me know how do these plants survive? Is their roots in sea water at all? It those are those roots adapted to these situations or their is some mgical thing happening there?

I hope i could have been able to explain my question as good as possible.

Thank you for your replies in advance.

Eqbal Vakilzadeh

Plants, like other forms of life, are adapted to fit certian circumstances. Not all trees are the same.

It is not just about adaptations. Obviously mangroves do live in brackish water. They have several adaptations to allow this. High quantities of salt in their cells that means water can move from the brackish water to the even saltier mangrove cells by osmosis. This would not be possible for regular trees as you suggest above. mangroves also have air tubes in their roots specifically to get the oxygen down to the tissues under water. You're right that hypoxia this is a very real problem for trees that live in standing water.

With respect to the islands, the key is that the ground water can push out the sea water. This web site has a diagram and description [3]. Even trees at the edge of the island it is possible for them to get fresh water. David D. (Talk) 21:41, 5 October 2005 (UTC)

This is it. thanks for the info and the link. eqbal

Computing

differences between windows nt and windows 98

Apart from the fact that they're both versions of Windows from Microsoft, nearly everything. The code bases and design rationales are entirely different, and that filters through the whole of both operating systems. Check out Windows NT and Windows 98 for more. — Lomn | Talk / RfC 18:04, 5 October 2005 (UTC)

manufacture of dimensions in nanometer range

How is the stylus tip made up of hard material like diamond which is used in surface roughness measurements manufactured to have a radius in the range of nanometers ?What is the procedure involved?

                --------------------------------------------------------------------

Aggregated diamond nanorods have been made by a new method and there are more conventional methods such as Chemical vapor deposition. --JWSchmidt 03:22, 8 October 2005 (UTC)

Unknown Energy?

Would it be right to say that energy in its pure form is unknown to us? For instance I cannot see the light that passes across my field of view. It seems that we can touch, hear, and see energy but only when it is interacting with the matter of our own bodies, our eyes, hears, or skin and in doing so does the energy that triggers the reaction of our senses changes it form? If so would it not also be so that what ever device we construct to measure energy would have the effect of changing the energy which we try to measure? Could or does energy exist in a form unknown out side the world of matter that we exist in? --Eye 19:57, 5 October 2005 (UTC)

Energy is a conserved quantity that is associated with location (potential energy), motion (kinetic energy), and with matter itself (see E=mc²). Possibly the best candidate for "pure energy" would be the photon, the massless light particle, and you are absolutely right that one only sees photons when they interact with the matter in your eyes (or, if they hit your skin, they can give you a sunburn). It is a principle of quantum mechanics that you cannot observe anything without changing it; this applies to energy in any form, regardless of the device you build. To answer your last question, dark matter and dark energy are two things whose affects we can observe in cosmology but whose nature remains unknown to us; they compose the vast majority of the energy of the universe. Hope that helps! -- SCZenz 20:09, 5 October 2005 (UTC)

Mmm...I like the dark energy bit.--Eye 22:06, 5 October 2005 (UTC)

Better known as the Measurement problem. - Cobra Ky (talk, contribs) 22:15, 5 October 2005 (UTC)

Anything that exists outside the reality we live in can not be observed by us and therefore does not exist as far as we can (ever) tell. Dark matter and energy are theoretical solutions to problems in cosmology. One could say that they are observed indirectly, but then everything is observed indirectly. When I look at a table I really just register the light that is reflected by it. And I don't even see the light, but only register the effect it has in my eyes and brains. DirkvdM 13:54, 6 October 2005 (UTC)

1. Would it be right to say that energy in its pure form is unknown to us? No, that is not right. Energy is very well understood in physics.
2. For instance I cannot see the light that passes across my field of view. You see light that interacts with your eyes. You don't see light that is not interacting with you. Same for sounds, pressure (touch) and so forth.
3. [D]oes the energy that triggers the reaction of our senses change its form? Yes.
4. If so would it not also be so that what ever device we construct to measure energy would have the effect of changing the energy which we try to measure? Yes.
5. Could or does energy exist in a form unknown out side the world of matter that we exist in? No. Matter is energy. Energy is matter. Forms change. WAS 4.250 21:33, 10 October 2005 (UTC)

water solubiliry in the body with homeostasis

How is water solubility used to maintain homeostasis in the body? What are four examples of this?

It all depends on what points your lecturer made. Was there reding material set with this problem. it might be worth checking that first.David D. (Talk) 22:41, 5 October 2005 (UTC)

Freshwater Invertebrates and Marine Invertebrates

I am trying to find the basic information on what differentiates certain freshwater invertebrates with marine invertebrates. For example, there are several invertebrates (Crayfish, Jellyfish, snails, etc.) that live in either freshwater or marine/sea water, what differentiates them? Why can one species of crayfish live only in freshwater and not in saltwater? How is the freshwater crayfish different from the marine crayfish?

If anyone can help me to answer this, I would REALLY appreciate it! Thanks!

• Our Crayfish article states that in New Zealand "the name crayfish or cray, refers to a spiny lobster, and crayfish are called freshwater crays or koura, the Maori name for the animal." Is that what you are referring to?

Alternatively, I suspect that the Speciation article referring to the emergence of new species through Evolution and Natural Selection. Capitalistroadster 01:17, 6 October 2005 (UTC)

The basic difference is physiological. The freshwater organisms are better at pumping excess water out of their bodies, thus maintaining the salinity of their cells, coelomic fluid or blood. WormRunner | Talk 02:57, 6 October 2005 (UTC)

DNA/Cloning

How much of a DNA sample is enough to make a clone of something? What is the best source of DNA in relation to cloning?

No one has successfully made a cloned animal with just a DNA sample to start with. alteripse 00:56, 6 October 2005 (UTC)

To make an actual clone of something, you'd need to replicate all of its DNA (or extract a full set). A full set of the DNA of any living thing is present in every one of its cells. You could also read Genetics, DNA, and Cloning --Borbrav 01:20, 6 October 2005 (UTC)

In addition to the DNA you need the right environment, starting with the right cell (although I believe you don't necessarily need a cell of that specific species - something closely related would do). And then that cell needs a womb (natural or artificial) to grow in. DirkvdM 13:58, 6 October 2005 (UTC)

And you might want to try the article on Polymerase chain reaction to answer your "amount" question. --Michael 04:03, 10 October 2005 (UTC)

Cloning is typically done with an easily obtained cell, like a skin cell, or in the case of Dolly, this first cloned sheep, an udder cell. Cloning usually takes hundreds of tries, using one cell per try.

Computer languages

what is an atom in some computer languages?

Take a look at Lisp atom, and also Prolog. There may be other meanings of the term in other programming languages.-gadfium 02:54, 6 October 2005 (UTC)

Killing Me Softfruit : Which food would kill you first?

Of all the things a person in a modern Western democracy might normally consume as part of a meal, which would kill with the lowest dosage? The test subject is to be fed on the test food alone and is allowed any quantity of water and time for comfort breaks. --bodnotbod 01:46, 6 October 2005 (UTC)

My guess would be alcohol. — Laura Scudder | Talk 01:54, 6 October 2005 (UTC)

Oooh, fun game. Tricky though. For instance if you include trace amounts of things that we ingest but don't intend to and are not conscious of, the answer would be aflatoxins, other natural neurotoxins like botulinum toxin, or pesticides and other chemical contaminants. We certainly "might normally consume as part of a meal" trace amounts of these things, but it would take only mg amounts to kill us.

Now if you restrict your contest to things that we deliberately and knowingly ingest as food, then alcohol seems a pretty good choice if taken as a single dose (1-3 oz of pure ethanol can be fatal to an adult), but if spaced out it would require a much larger amount. Same for caffeine. However, your allowance for "any quantity of ... time for comfort breaks" would suggest we could stretch out the exposure. So it looks like you'd better impose more rules. alteripse 03:08, 6 October 2005 (UTC)

• I wonder if you could kill yourself by OD'ing on salt? --jpgordon∇∆∇∆ 03:59, 6 October 2005 (UTC)

Of course. You can OD on water or oxygen also. The amount of salt that would kill you if you had access to sufficient water and could take "comfort breaks" to unload some of it would be larger than the mg of caffeine that would be fatal. However it is not a bad suggestion if the contest limited you to a single dose you had to ingest in one sitting. alteripse 04:07, 6 October 2005 (UTC)

Well, a relatively small bite of most anything that can be lodged in the throat has taken down multitudes over the ages but I think I am cheating. Qaz ^(talk) 04:14, 6 October 2005 (UTC)

If you knew you had a food allergy- you could do it will a minimal amount of the relavant food stuff.--nixie 04:19, 6 October 2005 (UTC)

Vinegar wouldn't do you too much good either under the test conditions. Salt would fairly quickly cause renal failure (or drowning, by the amount of water consumed - this has happened in France). Cooking oil might start dehydration by diarrhea, but probably wouldn't work as fast as the others. Anything infected with cholera would be pretty fatal, as would certain uncooked beans, but that must certainly be cheating! Physchim62 15:41, 7 October 2005 (UTC)

Most of these seem rather unappetising. Except maybe the alcohol. How about a couple of pounds of green potatoes, nicely cooked in the means of your choice? Notinasnaid 17:41, 7 October 2005 (UTC)

That's almost cheating, too, as you wouldn't normally eat it. Along similar lines I could propose what killed Christopher McCandless: potato seeds which he helpfully discovered become poisonous in August. But so far I think alcohol is the best bet so far as things you'd normally ingest and could get someone to down fast enough. — Laura Scudder | Talk 17:55, 7 October 2005 (UTC)

Could you add some detail about how Christopher McCandless died to that article? Superm401 | Talk 22:18, 15 October 2005 (UTC)

A freshman died from water intoxication recently during a hazing incident at California State University, Chico. User:Zoe|^(talk) 07:45, 9 October 2005 (UTC)

• Some interesting answers, but I was tending to think of food rather than drink, so alcohol would have been ruled out. I'd like an answer that doesn't involve taking out one of the ingredients / chemicals of a food and eating that in isolation unless you would normally eat it in isolation too. --bodnotbod 00:27, 13 October 2005 (UTC)

Are you planning to poison somebody?--Shanedidona 03:15, 13 October 2005 (UTC)

Neurotransmitter Receptor Unbinding

When neurotransmitters are released, they bind onto a receptor on the post-synaptic neuron, and open a ligand-gated channel. However, I can't find any details on how or if they 'unbind' so that this channel can reset, and the general mechanism of this occuring. Certainly, the pre-synaptic cell and enzymes have mechanisms to reduce the concentration of neurotransmitters in the cleft, but I don't see how this causes the neurotransmitter molecules to unbind and therefore allow the channel to be activated again. Any details on this mechanism or whether such a mechanism actually exists would be of great use. Thanks. --Lynto008 03:20, 6 October 2005 (UTC)

You are reminding my of the most boring part of by biomed courses :) I just whipped out my copy of Human Physiology (Vander, Sherman, and Lucino).

If memory serves, unbinding depends on the type of ion channel. [Ligands] "produce either an allosteric or covalent change in the shape of the channel protein. Such channels are termed "ligand-gated channels, and the ligands that influence them are often chemical messangers" (116). Those channels are often further subdivided. What turns the channels "off" depends on the type. It's often either the unbinding of the ligand, or a messanger lipid, or another enzyme ligand, 'etc. →Raul654 03:31, 6 October 2005 (UTC)

So when its said that the ligand 'binds' to the receptor, what is really meant is that it 'triggers' the receptor by changing it, rather than actually attaching? More like the ligand turns on a switch than acts like a key? Because the way that the article Neurotransmitters (and just about everything else i can find on the internet) puts it, "The neurotransmitters... bind to receptors.", which to me seems to imply that it attaches somehow and would remain on the channel triggering it until it is somehow cleaved off. I know that this seems a bit pedantic but to someone who is trying to grasp these concepts, it certainly makes a huge difference. Is it true that the ligands don't really 'bind' per se and that there is actually a distinction? If so, this needs to be mentioned somewhere in wikipedia. Thanks again. --Lynto008 07:50, 6 October 2005 (UTC)

What you are asking is really not biology, but more physical chemistry ;)

A ligand is, by defintion, something that chemically binds to something else. Neurotransmitters are ligands that bind *VERY WEAKLY* to receptors (ion-gated channels), meaning it takes very little energy to break such bonds. The process of binding causes the channel to change shape, allowing stuff to pass through it. However, the weak bonding means that it's very easy for the ligand to pop right back off - possibly even caused by thermal energy (remember, everything is vibrating very fast at the molecular level due to heat -- imagine trying to hold onto something slippery in the middle of an earthquake). →Raul654 08:00, 6 October 2005 (UTC)

Nevermind - I looked up allosteric. Means binding. Duh. --203.206.109.81 07:58, 6 October 2005 (UTC)

Technological trends in information systems

What are the key tehcnological trends that heighten ethical concerns?

I am taking "heighten ethical concerns" to mean "increase people's attention to the ethical aspects of their choice of behaviors." The key technological trends that allowed people to be aware of choices of behavior and to have the time energy and tools to think about ethics were were agriculture, hunting tools, food storage technology, and communication and recording technologies. If you mean something else by the phrase "heighten ethical concerns" please explain. alteripse 03:15, 6 October 2005 (UTC)

You might also educate yourself about the US law commonly called Sarbanes Oxley which imposed accountability standards on a wide spectrum of corporate and other entities doing business in the USA, in the wake of the accounting scandals that led to some of the largest companies in the world going bankrupt. These new regulations also imposed new rules on the information technology aspects of those companies, non-profits, unions, etc. that some people label as being ethical standards, and others label as additional money making sources for the lawyers, in a nation that is by the lawyers, for the lawyers and of the lawyers, with all the other residents being to provide the income to the lawyers. AlMac|^(talk) 04:59, 8 October 2005 (UTC)

longest ship in the world?

The best I can find is an entry in the middle of this section: A.P._Moller-Maersk_Group#1993_-_1999_:_bigger_and_bigger. -- SCZenz 03:39, 6 October 2005 (UTC)

• Seems to be that or the Queen Mary II. --jpgordon∇∆∇∆ 03:53, 6 October 2005 (UTC)

Unless the QMII's length is severely rounded, the transport ship I linked to has it by 1.9 m. -- SCZenz 03:58, 6 October 2005 (UTC)

Just a bit of trivia; the Great Eastern was built a century and a half before that but was almost 2/3 the size of these ships. Truly humungous for that time. DirkvdM 14:28, 6 October 2005 (UTC)

Queen Mary II is the longest cruise liner at 345 m LOA; Sovereign Mærsk is perhaps the longest container ship 346.9 m. But a number of supertankers are much bigger, for example, Knock Nevis, 458 m. Gdr 20:25, 6 October 2005 (UTC)

• Though it barely counts as a ship -- more like a storage facility these days! The article does a good job of describing Knock Nevis and its twisted history. --jpgordon∇∆∇∆ 21:54, 6 October 2005 (UTC)

Uranium 238 decay chain

Is the information listed in http://en.wikipedia.org/wiki/Decay_chain correct?

Should Uranium 238 decay into an alpha particle, Thorium 234 AND two electrons?

Giving off an alpha particle, plus two electrons, would change reduce the number of nucleons by four and leave the charge unchanged. This would result in U-234, as the page says. So it's at least self-consistent. The decay you indicate has a charge imbalance, unless I misunderstand. -- SCZenz 03:56, 6 October 2005 (UTC)

The alpha particle is a helium nucleus, which has two protons and two neutrons in it. Thus, the U-238 loses two protons, two electrons, and two neutrons, and so charge is balanced. --Borbrav 00:32, 7 October 2005 (UTC)

Yes and no. The nuclear decay of U-238 is by loss of an alpha particle to give ²³⁴Th²⁻: the thorium nucleus is not sufficiently close to hold on to the two electrons it has inherited and these are lost to the environment. See also electron affinity. Physchim62 15:47, 7 October 2005 (UTC)

Atoms and molecules

• In the absence of a specific question, I would suggest our articles on Atom and Molecule. Capitalistroadster 04:23, 6 October 2005 (UTC)

Sun & planet gear & epicyclic gearing

Does anyone know the connections between the sun and planet gear and epicyclic gearing. I don't know whether the later is a 'new' name for the former or developed from it or if they are unrelated but share some terminology? Any help would be much appreciated. AllanHainey 07:52, 6 October 2005 (UTC)

The original sun-and-planet gear setup involved only two gears, as stated at that article. What I've read (I don't remember where) is that it was invented for the specific reason that the invention of the steam engine had created a need to convert reciprocating to rotary power, and someone else had already patented the simpler approach of using a crank for that purpose. This would suggest that the more general epicyclic-gearing arrangements shown in that article were developed independently, for applications where this actually was the best form of gearing; but I don't actually know. --Anonymous, 01:30 UTC, October 12, 2005

Rules of significant figures involving addition.

The rule for rounding to significant figures for addition is to round to the least number of decimal places involved. However, if the example were 1.01 + 3. + 1.1 would the rounding go to 4 or to 4.1? AKA, does a figure with no decimals mean to round to no decimals, or is it the least after that?

This came up in class yesterday and I was just wondering what the specific rule for this was and any reasoning behind this. Thanks.

That would depend wether that specific number with no decimals is an exact number or not. For example, if my journey from home to school took 1.75 km then I would travel 2 * 1.75 = 3.50 km from home to school and back. If I have a yard of 2m by 3.71m the total surface area would be 2 * 3.71 = 12m7m². --R.Koot 14:26, 6 October 2005 (UTC)

Ah, trick question! 1.01 + 3. + 1.1 = 5.11 (not 4.whatever). As to how that should be rounded off, I'm a bit rusty, but I assume that the fact that there is a dot behind the 3 means that it's not exactly 3, but you don't have the numbers behind the dot, so you can't use those of the other numbers, so the answer is 4. (with a dot). As to whether that should be rounded off before or after the calculation, I forgot, but in this case the answers are the same. DirkvdM 14:40, 6 October 2005 (UTC)

Rounding for numbers of known higher precision should be done after calculations so as not to propagate rounding errors. Think of adding 2.7 4.6 2.55 and 3. Rounding before the addition causes the rounding errors to add getting the erroneus answer of 14, when it should be 13. It's a bigger deal with multiplication of course. - Taxman ^Talk 14:27, 7 October 2005 (UTC)

And R.Koot should go get his tuition fees back. 2 * 3.71 = 12m ? And I'm not referring to the omission of the '²'. DirkvdM 14:40, 6 October 2005 (UTC)

Uhhh... I don't even know what I meant there? --R.Koot 23:21, 6 October 2005 (UTC)

Thanks, Dirk. THat answered my question.... And nice catch on the 3 + 1 + 1 = 5... Oops!

Whenever you add, you keep all and only the decimals which were known in all of the numbers you were adding. i.e. 2.45+3.891=6.34, not 6.341. --Borbrav 00:22, 7 October 2005 (UTC)

Rounding rules have different schools of thought based on the context of what is being arithmeticed.

Suppose the military needs to move a certain volume of men and equipment, and the math comes out that to do this, they need 11.2 army trucks, the answer is not 11 trucks but 12, because there are cases where you always round up. AlMac|^(talk) 05:02, 8 October 2005 (UTC)

English name of pen&paper game

The game is popular among Russian students. The rules are described here. "Pests" is a code-name. It's called "клопы" (a kind of pest) or "тараканы" (roaches) in Russian. I hope someone knows how it's called in English.  Grue  13:38, 6 October 2005 (UTC)

The rules sound conceptually similar to several other games I am familiar with:

• The game of GO, which is an oriental guerrilla game sometimes considered to be the mental equivalent of CHESS, and several played on same kind of grid, with race to get some number in a row.
• The game of LIFE which can be played solitaire, or in competition. There are variations on the game of LIFE, such as VIRUS, in which you design simple algorithms for growth of your PESTs to try to eat away at the enemy LIFE. I think some nuts have taken that interest into the design of computer viruses.
• Then there are a number of ECOLOGY games played using different colored multi-sided dice (more than 6 sides) where the number on top represents the population of that animal or plant, which eats adjacent as food, leading to an increase in the population, but if there is not enough food, the population decreases.

AlMac|^(talk) 18:39, 15 October 2005 (UTC)

depersonalization

What is the original reference for the information contained on your website concerning depersonalization, particularly the information regarding suicide ( as well as the general information provided). I have seen this exact wording on several other websites, but no references for the information.

Thank you,

Donna McCleary

• You can contact the people who contributed to the article, each of them is listed in the article's edit history. The links in the article appear to be authorative on the subject, so you might want to visit those and ask the people there for reliable references too. - Mgm|^(talk) 15:50, 6 October 2005 (UTC)

helium

where did the name helium come from?

• From Helium#History: "He and English chemist Edward Frankland named the element after the Greek word for the Sun god, Helios, and, assuming it was a metal, gave it an -ium ending (a mistake that was never corrected)." - Mgm|^(talk) 15:52, 6 October 2005 (UTC)
• If I remember rightly it was named after the sun because it was discovered after observing the spectrum of the sun's light during an eclipse.--stib 03:31, 13 October 2005 (UTC)

Heroin In Food

Until this AM I could not understand why I am having so many problems with my? Now I do.The reason I was asking about info. on ingesting heroin in food,is because that is how our daughter,Shenel,was murdered.People do not eat heroin,so we can find no info.on Toxicological Findings.That is ALL this is about!The FACTS!Any & all we can possibly get.As far as I know,and I have researched alot of drug sites,nobody knows.We did find alot of very good info.here,so I thought maybe you could find the answer to our ?.I just wish you would of let me know there was a problem with our ? instead of just deleting it.We'd still appreciate an answer,if you can find one.Our hearts are broken and she left behind two children.Eric was 4 , and Alyssa was 5 weeks old.Someday,if we can,we want to be able to explain all of this to Eric.Alyssa is with the man who killed her mother,so we lost her too.The sites we have gone on in New Zeland and Australia,which have done alot of studies on heroin,have made us realize the U.S.has alot to learn.Because of their lack of knowledge,this man got away with murder.It happens more often than you would ever believe,and we are all paying the price.We would be so grateful if you can help us?If not, I will know when I come back and see I have once again been deleted.I do want to thank you for all the good info.you did provide us with and say good-bye for now. Toni

Toni, I sympathise with your situation, talk about stressful. No one has deleted your questions. Your first post with replies is still here, but you need to scroll up a long way to find it. Likewise your second post is still present. Realise that new topics are being added to this pages rapidly. David D. (Talk) 18:28, 6 October 2005 (UTC)

Regarding Heads

There was some talk around here a few days ago regarding the possibility of head transplants. The general consensus seems to be that there is no real reason a head could not be transplanted onto a donor body and live, albeit as a quadriplegic. So the question that occurs to me is this: Is the classic sci-fi/horror staple of a severed head being kept alive, artifically, possible? What about the even more cliched "brain in a jar"? With an oxygenated/nutrient enriched blood supply, under strictly controlled hospital conditions, is there any reason why a human head could not be kept alive, other than ethical ones? Brian Schlosser42 18:32, 6 October 2005 (UTC)

Should be fine in theory.

But very difficult in practice. Certainly well beyond the current state of the art. See the Wikipedia articles on head transplants and whole-body transplants. Gdr 20:00, 6 October 2005 (UTC)

I'm not sure it would be that difficult in practice, certainly a non-trivial proposition, but given the success of primate head transplants, I would think that simply keeping a human (I presume that the questioner is talking about humans) head alive would be well within the current state of the art. The major obstacles to actually doing this would be ethical, not medical.

Funny that only a brain transplant is also called a whole body transplant. The same could be said for a head transplant I'd say. Also funny that the article on the former nevertheless goes on to speak about tranplanting the brain to another body. The alternative name exists for a reason (if one assumes personality resides in the brain). DirkvdM 20:40, 6 October 2005 (UTC)

The success of Dr. White's head transplants is, I think, rather overstated by our article. In the best cases, the head survived for several hours and showed signs of consciousness. Gdr 20:45, 6 October 2005 (UTC)

word password recovery

There is a free or open source word password recovery program, but I have lost it - does anyone know it? Thanks!

One program that is free for 30 days is Elcomsoft Advanced Office Password Recovery. I haven't tried it so I can't vouch for it, but it might get you out of immediate trouble. There are lots of other programs but this was the first I found which appears to have a fully functional demo available.-gadfium 03:05, 7 October 2005 (UTC)

Elements

What is the importance of Iron?

• Reading Iron would be a good start. It's the final end-product of nuclear fusion, and steel is made from it. I think that's enough hints to start your essay! ;) -- SCZenz 21:38, 6 October 2005 (UTC)
• Lets not give short shrift to its role in hemoglobin. There is also its role in that time... what was it called... oh yeah, it was the Iron Age. Qaz ^(talk) 06:25, 8 October 2005 (UTC)
• Iron is one of the few metals we know of affected by magnetic fields. Rob Church ^{Talk | FAD} 15:49, 9 October 2005 (UTC)
• If you don't use it your clothes end up wrinkled. DJ Clayworth 17:58, 7 October 2005 (UTC)
  • Unless you have decent clothes that don't wrinkle. DirkvdM 09:32, 8 October 2005 (UTC)
    • Or use a tumble dryer, and get them out quickly enough afterwards. Certain clothes can be hung to allow the wrinkles to fall out too. Rob Church ^{Talk | FAD} 15:49, 9 October 2005 (UTC)
      • The problem with this approach is that the fallen wrinkles collect at the bottom of your closet. If you don't wear socks or slippers, the wrinkles can then be transferred to your skin. (Ironing avoids this problem; the high heat inactivates wrinkles, which can then be transferred back down the powerlines for safe permanent disposal by the electric company.) TenOfAllTrades(talk) 16:10, 9 October 2005 (UTC)

Guys,guys, come on it's a serious question...without iron the wheels would fall off my truck...I wouldn't even have a truck...

Look at any skyline of a major city today.

Look at pictures of city skylines from 100 years ago.

Consider how it became possible to build them so much higher, thanks to modern development of metals and other building materials, and consider what they might look like 100 years from now ... will space elevators become commonplace?

AlMac|^(talk) 09:09, 10 October 2005 (UTC)

Consider the importance of magnetism to the development of many modern conveniences, such as computers. AlMac|^(talk) 09:10, 10 October 2005 (UTC)

Apparently this is another essay question (header added subsequently)

State two ways in which a singled-celled organism, such as an amoeba, and a human body cell are alike.

Any number of properties in cell might suffice, but my two favorites are:

1. They're both smaller than a breadbox.
2. Neither one, under most circumstances, contains very much uranium.

If I were you, I would write your essay based on something else, though. ;) -- SCZenz 22:22, 6 October 2005 (UTC)

Biology

Plants produce cholorophyll to capture the energy from the suns ray's and take in carbon dioxide from the air, and water from the soil. What characteristic of living things does the show?

Their tendency not to do their own homework. (LOL, great answer !)

In seriousness, you should ask a more specific question. That describes lots of characteristics of living things; I suspect that only one of them, however, is on your vocabulary list for the week. RSpeer 22:23, 6 October 2005 (UTC)

You might look at Life, in particular Life#A conventional definition. -- SCZenz 22:24, 6 October 2005 (UTC)

Adaptation?

Ears

What animals have ears on the sides of their body? ...rabbits on my bumper--Eye 20:28, 9 October 2005 (UTC) and What animals have ears on their antennae? ...flies on my windscreen--Eye 20:28, 9 October 2005 (UTC)

--24.214.167.141 22:57, 6 October 2005 (UTC)

Smelling Extract

I am battling a stopped up nose and I once heard that smelling peppermint extract could break up the mucus. Does this work? Would sniffing the extract fumes kill brain cells? Could it get me high?

Your brain cells are dying as we speak anyway, and I suspect wine would do more damage to them than peppermint. Why not try it and report back here?--inks^T 04:47, 7 October 2005 (UTC)

I suggest you visit a pharmacy, sometimes called a drug store (that sells legal drugs) and direct your question to the pharmacist there. Typically there are scores of different brand names of remedies, at very reasonable prices. AlMac|^(talk) 05:07, 8 October 2005 (UTC)

Cough drops create substantial vapors, that will serve such a purpose, while you suck on them. I suggest a menthol-eucalytptis blend, that really does the trick. StuRat 05:34, 9 October 2005 (UTC)

One up each nostril should work --Eye 20:25, 9 October 2005 (UTC)

how do telescopes work?

Optical telescopes use a series of lenses to magnify distant objects, the same way a microscope does. Other types of telescopes are a bit more compliated. →Raul654 04:23, 7 October 2005 (UTC)

• Our Telescope article should be of some assistance as should the articles on specific types of telescope listed at the bottom of the telescope article. Capitalistroadster 05:01, 7 October 2005 (UTC)
• Also, if you typed this query into google, your second hit would've been this page from HowStuffWorks.com which has some info which may help you if you find the Wikipedia article too difficult to understand. - Mgm|^(talk) 16:31, 7 October 2005 (UTC)

Why do some noises cause goosebumps?

When someone scrapes their fingernails against a chalkboard, I get goosebumps. What is the reason in this?

I'm not sure exactly why sound initiates goosebumps, but the reaction is vestigial. Back when humans had hair covering their bodies, the reaction which is technically called piloerection, was intended to make ourselves appear larger, much like a cat does today when they are frightened. My guess would be, that a scary sound also triggers this reaction (like for instance the roar of a lion). Hope that helps. - Cobra Ky (talk, contribs) 17:18, 7 October 2005 (UTC)

medical term

What is meant by 'osteophytic lipping'?

Rgds, --Ciesse 203 13:52, 7 October 2005 (UTC)

Osteophytes are small projections of new bone growth or thickening. Lipping is a description of an x ray appearance. We need more context to interpret this, or you can ask your doctor. alteripse 19:46, 7 October 2005 (UTC)

I can actually answer this. They are indeed bony projections, usually found on the outer edges of articular surfaces of joints. Occurs in people exposed to heavy loads (eg. slave labourers) and elderly. Yay! My BSc in Anatomy was useful for something! This calls for a party!.....--inks^T 02:46, 8 October 2005 (UTC)

How do protons(+) not repel eachother...and....

how do electrons(-) not stick together with protons(+)??

For the first question, this is the strong interaction - it's effectively nonexistent at long distances, but over very small distances (like those inside an atomic nucleus) it's very powerfully attractive. This is more powerful than the electromagnetic force, so it holds them together. See atomic nucleus. Think of it this way - two positive poles of a magnet will strongly repel each other, but if you duct-tape them together they won't actually be able to break apart, because the tape is stronger than the magnetism.

For the second question, think of them as orbiting the nucleus very fast - they're falling toward the atom, yes, but satellites are also always pulled towards the earth by gravity, and they don't land on the surface. This isn't a very accurate description, but you might find it helps make sense of the problem. Shimgray | talk | 14:48, 7 October 2005 (UTC)

Two protons, with no neutrons present, actually do repel each other. The strong nuclear force only helps in a nucleus where neutrons are present also. By the way, these are great questions--they were central mysteries of physics for much of the early 20th century. -- SCZenz 15:35, 7 October 2005 (UTC)

Also, remember that an electron is not a thing (like a little ball), but more like a wave, or ring of evergy around the nucleus. It has to remain at a specific distance in order to orbit around the nucleus, determined by it's wavelength. --Mary

A good question to ask is how do neutrons help keep protons together in cases where the absence of neutrons woudl cause the protons to repel each other? Next question is why are neutrons stable in the nucleus when protons are present, but decay into a hydrogen atom when alone?

Those are also good questions.

1. The answer to the first is that the strong force between the proton and neutron is stronger than either the proton-proton or neutron-neutron force, and is enough to bind a proton to a neutron. So you can think of a nucleus as being more bound by the proton-neutron attraction than anything else (although the other interactions contribute too, they wouldn't be enough by themselves).
2. The answer to the second, I think, has to do with energy. A free neutron has more energy than its decay producs (e.g. a proton, an electron, and an antineutrino). But for most nuclei containing a neutron, the energy is actually lower as things are now than it would be if the decay happened. (Because of nucleus stability/bond strength issues in question 1.) Thus a free neutron decays, whereas neutrons in nuclei don't. Interestingly, nuclei with too many neutrons will have lower energy if a decay happens, and there the neutrons do undergo beta decay.

Hope that helps! -- SCZenz 22:41, 7 October 2005 (UTC)

Protons DO repel each other, but in the nuceus of an atom that repulsion is overpowered by the more powerful yet shorter distance acting force called strong interaction. Electons DO stick to the nucleus (protons and neutrons) of an atom; they are just millions of times BIGGER than the nucleus (visualize cotton balls glued to BBs). At the particle level, heavier things are smaller and lighter things are bigger due to the wave nature of things. The electrons get as close to the nucleus as they can, and their wave nature describes a shape looking like a donut or a sphere or a set of teardrops or other shapes (these are called orbitals, altho nothing is really orbiting). Talk about electrons orbiting is a heuristic in that it is a useful model without being accurate. WAS 4.250 22:04, 10 October 2005 (UTC)

Perl or Python?

I'm a budding computer programmer with free time on my hands. Is it better (more useful / more marketable in the job market) to learn Perl or Python? Or something else? I currently know Java and Prolog. Thanks!

Mary

It's a bit of a tossup. Perl and Python both do pretty much the same thing in about the same amount of code at about the same speed. The primary differences are that (1) Python is far, far easier easier to learn and to read (it's easy to read someone else's python code) while Perl is (as a colleague of mind humerously noted) a "write only language" (2) On the other hand, Perl has been around three times longer than Python, and is more entrenched in the market. So where the job market is concerned, Perl is probably more attractive from that perspective. →Raul654 22:48, 7 October 2005 (UTC)

Python is fun. Perl is not. I'd go with the former. Garrett Albright 01:34, 8 October 2005 (UTC)

Do a search for Perl and Python on a recruitment website and see which ones look most interesting. Perl jobs tend to be mostly Internet service providers (and spammers if you're evil). The mobile phone industry is starting to use Python apparently, and I agree that it's nicer to use than Perl. You can also play with Ruby, which is somewhere in the middle, or Lisp if you're a follower of Philip Greenspun and Paul Graham. Ojw 15:03, 8 October 2005 (UTC)

Nonsense. How is Perl "not fun"? How do you quantify a language being "fun" anyway? Dysprosia 04:08, 9 October 2005 (UTC)

Oh, I won't lie and say that I wasn't being subjective. But the fact remains that Perl has a much higher level of entry than any other major language out there; it's like you can't help but write obfuscated code. The OP said she already knows some other languages, so I'd bet she could pick up Python in a snap because it's quite easy to "read." Perl, not so much. And since productive programming is fun programming, she'd be able to start having fun in Python much sooner, I'd bet. Garrett Albright 08:10, 9 October 2005 (UTC)

I doubt that. To do something in Perl requires the same basic knowledge to do the same in Python. Perl is quite easy to read too, if you write it in a certain way. (It's not that I'm trying to be Perl-partisan here, I'm not, I just feel that some criticism of Perl tends to be overrated.) Dysprosia 11:34, 9 October 2005 (UTC)

Why do men have nipples?

Ya, I said it! But I would seriously like to know. - Cobra Ky (talk, contribs) 17:21, 7 October 2005 (UTC)

Men actually have complete breasts, not just nipples...they are just underdeveloped. --Phroziac^(talk) 17:27, 7 October 2005 (UTC)

Well, usually! Manboobs! — ceejayoz ^{★ .com} 03:35, 9 October 2005 (UTC)

Why? - Cobra Ky (talk, contribs) 17:28, 7 October 2005 (UTC)

I think sexual differentiation could answer some of your questions. Most male and female organs develop from the same undifferentiated fetal organs; they simply develop differently under the influence of hormones. Female hormones stimulate the development of breasts during puberty, so women's proto-breasts develop while men's don't. — Laura Scudder | Talk 18:13, 7 October 2005 (UTC)

• Stephen J. Gould's essay "Male Nipples and Clitoral Ripples" is a pretty good essay on the subject. I think it's in Bully for Brontosaurus. --Bob Mellish 18:20, 7 October 2005 (UTC)

The short answer is that there has been no biological reason to eliminate them. The genes for nipples are very ancient ones common to both sexes of all mammals and are not carried on the Y chromosome. The basic equipment of a nipple is biologically cheap. It is made operational when needed by hormone signals. A defect of nipple or breast development carries little reproductive penalty to a man but a strong reproductive penalty to the other 50% of the population, so nipples continue to be advantageous and evolutionarily conserved. An intelligent designer of course would not bother to design a male with them: this type of trait is far better explained by evolution than by any competing hypothesis. alteripse 19:43, 7 October 2005 (UTC)

The biological reason to eliminate them is not strong enough to cause them to be eliminated, much like the appendix.

Thanks for the answers everyone. I believe I thoroughly understand now. The reference to intelligent design was quite interesting as well; another score for evolution theory. - Cobra Ky (talk, contribs) 23:05, 7 October 2005 (UTC)

I think User:Alteripse is giving the field of intelligent design far too much credit by supposing it makes any testable claims about the nature of the designer. Gdr 13:12, 8 October 2005 (UTC)

There is an interesting parallel in industry, where it is frequently cheaper to make everything the same, even if that means some "additional equipment" is included that was not "ordered". For example, circuit boards are often built with everything and then those options the customer doesn't want are burned off or otherwise disabled. It doesn't seem intuitive that this is efficent, but the cost of producing many different types of circuit boards apparently is more than the cost of destroying unwanted components. StuRat 05:12, 9 October 2005 (UTC)

Men have nipples because in the early stages of developments inside the womb Males and females are basically indistinguishable. In other words, we all start out from the same "template".

Well yes, but the more interesting question is why we all start out the same. It would also be possible for male bodies to eliminate nipples later in life, much as we lose baby teeth, if there was some value to doing so. StuRat 13:48, 14 October 2005 (UTC)

Can Big Red gum cause permanent tongue damage?

If you cover your tongue with Big Red chewing gum and stick it out of your mouth for an extended period of time could it cause permanent damage?

• I am not sure what mechanism of harm is worrying you, but the surface of the tongue heals even faster than the surface of the skin. alteripse 19:44, 7 October 2005 (UTC)
  • Really? I didn't knew that. Could you add what you know to tongue? ☢ Kieff | Talk 23:02, 7 October 2005 (UTC)
    • It's just that the tongue and inside of the mouth are mucous membrane tissue. Although not as tough as epidermis, mucosal membranes have a blood supply that is more plentiful and closer to the surface and have a higher density of immune cells and are more resistant to wound infection. I suspect (off the top of my head) that there are higher densities of precursor cells and faster responses to injury in mucosal membrane compared to skin. In practical terms, this is why doctors in emergency rooms dont even bother to suture cuts in the inside of the mouth unless the tongue is almost severed (I am exaggerating only a bit here). alteripse 00:55, 8 October 2005 (UTC)

• Yeah, probably not. It is unlikely any worse than burning one's tongue on very hot food -- it might hurt like an SOB for a few days but it heals pretty quick. --Fastfission 19:47, 7 October 2005 (UTC)

Frosty Question

On bright, still, autumn mornings just before the sun comes up I notice that the dew on my car windscreen is not frozen and then as the sun rises above the horizon the dew freezes. Is it possible that the solar wind passing the edge of the earth can cause the tempter to fall? I have noticed this happen on dozens of occasions over the years. Is there a link? --Eye 20:31, 7 October 2005 (UTC)

The short answer to your question, I believe, is no. Sunlight isn't going to make anything on earth colder. Sadly, I have no idea what actually is going on. -- SCZenz 23:07, 7 October 2005 (UTC)

If you think about it, the Earth doesn't start warming up from the Sun's rays untill well after sunrise. Thus, it could be just that the Earth is still cooling down, and the sunrise and freezing are unrelated. --Borbrav 04:01, 8 October 2005 (UTC)

Dew freezing on the windscreen is a rare occurance in my part of the world, but I do know that in the middle of winter (in my location of Perth at least) the day's lowest temperature occurs about 20-30 minutes after sunrise so I wouldn't think it's a solar wind thing.--Commander Keane 06:11, 8 October 2005 (UTC)

You spend your sunrises looking through a car window? Did you cheat on your wife and get kicked out of the house? :) I wish :-) --Eye 21:16, 8 October 2005 (UTC)

But more seriously, I'm thinking about the influence of wind. I've often noticed that around sunset/rise the air suddenly becomes very still. Maybe a slight wind prevented the previous formation of frost.

This makes me think of something else I've often noticed. When you boil water and then turn off the gas (if you use gas, that is - an electric stove works too slow for this) you suddenly get (more) steam. The reason for that, I assume, is that previously the hot air rising along the sides of the pot prevented the steam from forming. But if you turn off the gas, the water at first still boils and keeps on saturating the air. And the saturated air finally gets a chance to form steam. DirkvdM 18:01, 8 October 2005 (UTC)

Maybe frost isn’t the right word. What happens is that the dew freezes. The drop in temperature is very slight but enough and occurs after the sun has risen. A drop in the wind might be a more feasible answer but that is so with most frosty days. Maybe there is a weather person out there? --Eye 21:16, 8 October 2005 (UTC)

Shortly after dawn the sunlight is coming in at such a shallow angle that it provides little heating, such that the thermal loss into space is greater. That means the temperature, on average, will continue to drop until the Sun gets to a more respectable angle. I said "on average", since local weather fronts can easily overwhelm this slight effect. StuRat 05:03, 9 October 2005 (UTC)

I had an interesting frost phenomenon on a car of mine. Frost would form on the hood then melt as the air warmed up, except for the areas of the hood with the cross supports under them, since they kept those parts of the hood cool a few minutes longer. The result was a frost X-ray of the hood ! StuRat 05:19, 9 October 2005 (UTC)

carbohydrate chart

How many grams of carbohydrate are in various common foods?

• Any site on the Atkins diet would keep such a list. You'd have to be more specific about which foods you're talking about if you want a useful answers from us. - Mgm|^(talk) 22:12, 7 October 2005 (UTC)

Google carbohydrate content or carbohydrate list. You will find dozens of such lists, if not hundreds. alteripse 00:49, 8 October 2005 (UTC)

This site provides a fairly comprehensive list of nutritional info for many foods:

http://www.nutritiondata.com

StuRat 04:58, 9 October 2005 (UTC)

carbon trading

WHAT IS THE SCOPE FOR INDIAN INDUSTRIES IN CARBON TRADING?

BY, SRUJANA FINAL YEAR B.E(CSE) PLEASE GIVE ME ANSWER TO MY MAIL-ID

• I've also seen this question in the Humanities reference desk, please only post it in one reference desk subsection. - Mgm|^(talk) 08:15, 8 October 2005 (UTC)
• Srujana,

I have removed your e-mail as answers are not returned and you will start becoming more of a target for spam. Our Carbons emission trading article is a good start and our Economy of India article should give you some idea of the challenges. This release from the International Emissions Trading Association states that India has started trading [4]. These newspaper articles show that Biofuel and tree plantations are targets see [5] and [6]. Capitalistroadster 05:32, 9 October 2005 (UTC)

I'm not sure what you are refering to specifically but Kyoto Protocol doesn't require developing countries such as India to restrict its carbon emissions. Only those of Annex 1 in the Protocol that are required to cap their emissions. __earth 14:37, 11 October 2005 (UTC)

Smoke

Is there a way to add a color to smoke? For example, adding a substance to a cigarette to colorize the smoke. Is this possible?

Sure, but most people think it would make cigarettes even more offensive. alteripse 12:31, 8 October 2005 (UTC)

Fireworks? DirkvdM 13:44, 8 October 2005 (UTC)

See the "common pyrotechnic compounds" section of our fireworks article. Shantavira 16:56, 8 October 2005 (UTC)

Note that you don't want to add most of those compounds to a cigarette. Doing so would tend to make them much more rapidly and efficiently deadly than they already are. Note as well that those compounds will give a coloured flame, but won't typically have an appreciable effect on the smoke. TenOfAllTrades(talk) 03:24, 9 October 2005 (UTC)

There are some colored gases, like the purple of iodine or the green of chlorine, but those aren't the type of things you would want to inhale. StuRat 04:51, 9 October 2005 (UTC)

The question mentions cigarette smoke only as an example, so the answer should not focus on that. And certainly not the act of smoking, because that can hardly be the intent, unless it's a machine that smokes for some research or something. What is the reason for the question? DirkvdM 13:06, 9 October 2005 (UTC)

If you're asking because you want to film or photograph the smoke, then you could use coloured light to give the smoke a tint. Ojw 13:27, 9 October 2005 (UTC)

Generic Drugs

Is there a real difference between a generic and brand drug? I know they have to have the same active ingredient and have to be the same quality and everything, but then why do some doctors insist that a patient takes the brand and not the generic version? And why do so many people claim that the generic version of a drug do not work?

Some time ago there was a discussion in Dutch politics if doctors should not be forbidden to prescribe those unnecessarily expensive drugs and if national health insurance should cover that (or only restitute the normal price). I don't know what the outcome was (or indeed how informed the politicians were). Doctors may receive money for pushing certain brands. And if the drug is sold by themselves, they will likely make a bigger profit from a more expensive drug (which is why that is not the way it works in the Netherlands). People in general may make such claims because with health one should not take risks and therefore the more expensive option should be chosen (as if that is ever any guarantee - especially when you don't really know what you're buying). But now I'm only guessing. It's comparable to the inflated prices of condoms and funerals - not the sort of thing with which people are inclined to complain about the price. Fyi, I pay about 0.10 € each for my condoms. Well, for that I need to buy a gros, but they keep for years and the point is that it's a good indication what a reasonable price would be. DirkvdM 13:58, 8 October 2005 (UTC)

Is there a difference? In a word, sometimes. Most of the time for most drugs and most people a generic will work as well at a lower price. For some drugs in some people the difference between a generic and brand name may more than trivial. The problem is that it is difficult to predict ahead of time. alteripse 05:51, 9 October 2005 (UTC)

Our Generic drug article states that they are bioequivalent to the brand drug. However, in 50% of cases there is no generic drug as the term of the patent has not expired. There may also be a newer drug which may be more effective but may also be more expensive. In short, it depends on the circumstances. Capitalistroadster 06:11, 9 October 2005 (UTC)

Postural Drop related to Scleroderma and Kidney Disease

Dear Wikipedia Volunteer,

I have just found out about your service in a Sydney newspaper and am very excited at its potential.

Having just searched in Wikipedia for "postural drop" no results were available, although I am aware that Google, at least, does provide some references.

I sincerely hope that some of your readers, or whoever, can throw some light on this serious and deilitating condition.

Kind Regards, Arthur Major --203.164.32.81 07:19, 8 October 2005 (UTC)

See orthostatic hypotension. alteripse 12:32, 8 October 2005 (UTC)

WBC Booster

Sorry if this is a repeat post, but I accidently posted this in another category.

I know there are drugs that some athletes take to increase their red blood cell count, but are there any drugs that increase the number of white blood cells?

• It's been answered at Wikipedia:Reference_desk/Miscellaneous#WBC Booster. - Mgm|^(talk) 08:25, 8 October 2005 (UTC)

Coming out with generics

I was wondering why sometimes it takes so long for a generic drug to come out. I read something about the patents for allegra and I think flonase expiring and it was about a year ago I think, but generic versions are not available yet, why is this?

• Even when derived from the patented brand, generic drugs still need to do research to use the information to make a useful drug after which they need to have it tested and get all sorts of forms from government and health organizations. It's just a long, long process. - Mgm|^(talk) 19:37, 8 October 2005 (UTC)
  • It isn't always profitable to do so, either, especially if the brand name drug is fairly cheap already. — ceejayoz ^{★ .com} 03:33, 9 October 2005 (UTC)

Muscles wasting

My cousins muscles are wasting away and the doctors told him he will eventually be in a wheelchair. The doctors also said there are no drugs currently that could help him and the only thing he could do is physical therepy. I was wondering if something like steroids would help him out? I know they are illegal and arent very safe or healthy, but would it work and stop or slow down the wasting of his muscles?

Anabolic steroids are used sometimes for medical purposes, so I think that if they could help your cousin, his doctors would have thought of that too. Why not ask them about it? David Sneek 12:16, 8 October 2005 (UTC)

If your cousin has a muscular dystrophy there have been many clnical trials of anabolic steroids as well as glucocorticoids and growth hormone. They have not been found beneficial and sometimes have accelerated loss of strength. Search Medline for these terms if you want to find out for yourself. The muscular dystrophies are truly nasty diseases with few treatment options except support for most; I am sorry for your cousin. alteripse 12:30, 8 October 2005 (UTC)

• It sounds like Muscular dystrophy probably Duchenne muscular dystrophy to me. In answer to your question, this fact sheet from the Muscular Dystrophy campaign outlines that steroids are being used to treat muscular dystrophy see [7]. I have two young nephews with the disease and the good news is that research in a number of areas is delivering promising results. Wyeth are conducting human clinical trials of a treatment in adult muscular dystrophy see [8] According the National Institutes of Health, there are 13 clinical trials underway for various forms of muscular dystrohy see [9]. There have been positive outcomes in animal trials for gene therapy in recent times as well. Capitalistroadster 07:15, 9 October 2005 (UTC)

This is a nicer answer, with refs, than my gloomy one. Note that the "steroids being used to treat muscular dystrophy" in the MDA ref are glucocorticoids rather than anabolic steroids. The disease and both types of steroids have been well known for about 60 years. I didn't realize anyone was still running trials on glucocorticoids, but I didn't try to look it up. I hope some the cited research changes the traditionally pessimistic picture to which I alluded. alteripse 12:33, 9 October 2005 (UTC)

Pharmacy School

I'm interesting in applying for pharmacy school in the next few years, I was wondering how to increase my chances of getting in. I know good grades and a good PCAT score are important and also volunteering in a pharmacy, but what else can I do to increase my chances of getting in a good school?

Also, what questions do they ask at the interview? Thanks

Here is the same advice I would give if you asked about medical school or veterinary school. Concentrate on your grades, especially math and science. Most of the applicants whose grades and scores are within 10% of the average for last entering class will be offered admission, as will some of those whose grades and scores are below that. The principal purpose of the interview is identify unusual positive or negative characteristics that they cannot easily determine by the paper application, or cannot legally or publicly admit to using. Many of these characteristics are those you don't have control over. Another purpose of having an interview is to introduce a subjective element into the process so that taking one person over another with higher numbers can be justified.

If your grades and scores are at least average for the entering classes for that school, the prinicipal purpose of the in-person interview is to detect a disqualifying characteristic. This may differ widely depending on time, place, and local circumstances. One example might be race. Another might be an inability to hold a basic conversation and communicate. Another might be an appearance that suggests potential problems fitting in with the class and reflecting positively on the school. Another might be an extreme disability or an apparent mental illness. Another might be an indication that you would be unlikely to accept an offer of admission. In other words, the admission is yours to lose by the interview.

On the other hand, if your grades and scores are substantially below average for their usual entering class, the principal purpose of the interview is to look for an undetected asset. This may differ widely depending on time, place, and local circumstance. One example, especially in the US, may be race. Another might be an unusually impressive or attractive personal manner. Another might be to confirm other non-quantitative accomplishments. Another asset might be a family connection with the school or something to convince them you are more likely to accept and complete school than the other below-average candidates. Another might be wealth or political connection that could be of advantage to the school. In other words, a small number of students with well-below-average scores will win admission based on other things detected at the interview.

In other words the exact answers to the questions are not the point; it is the chance to detect other things. Work hard so you are in the first group and don't worry about the interview. alteripse 11:43, 8 October 2005 (UTC)

internet

• You found it. Any questions? Qaz ^(talk) 08:23, 8 October 2005 (UTC)
• By just getting here to ask the question, you must have used the internet. Like the person who asked what is operating system had to ahve used a computer to use the internet to get here to post the question. So we have people driving over the information superhighway who are not familiar with the terminology of the infrastructure involved, comparable to a person who drives a personal automobile, but does not know what a highway is. What is computer literacy coming to? AlMac|^(talk) 15:41, 8 October 2005 (UTC)

Maths: Asymptotic Series

Can anyone help me solve this:

You are given a function

$f(x)=(x+1)e^{\frac {-1}{x}}$.

Find $a\,$, $b\,$ and $c\,$ so that the formula

$f(x)=ax+b+{\frac {c}{x}}+o\left({\frac {1}{x}}\right)$

is true when $x\to -\infty$.

Thank you.

Here's a hint to help you with your homework: consider the Taylor series for $e^{\frac {-1}{x}}$. Gdr 14:00, 8 October 2005 (UTC)

The question makes no sense. How can $ax$ and $o(x)$ be in there both? Anyway,

$e^{\frac {-1}{x}}=1-{\frac {1}{x}}+{\frac {1}{x^{2}}}+...$, so

$f(x)=x+{\frac {1}{x^{2}}}+...$

meaning $a=1\,$, $b=c=0\,$. 82.210.119.82 15:10, 8 October 2005 (UTC)

See our article Big O notation for an explanation of little o notation, but essentially $f(x)=o(g(x))\ \iff {\frac {f(x)}{g(x)}}\to 0\,$ as $x\to \infty \,$. Little o notation is mostly used by mathematicians; a computer scientist would have used big O notation and written $O\left({\frac {1}{x^{2}}}\right)\,$ here (with much the same meaning).

As for your derivation, you've got the Taylor series for $e^{x}$ wrong. Gdr 15:56, 8 October 2005 (UTC)

But if $e^{\frac {1}{x}}\,$, how does $x\to -\infty$ change the thing — in what way is it different from $x\to \infty$?

Chemistry: Small Mushroom Cloud?

I recall seeing a video of a (probably high school) chemistry lab. A teacher poured the contents of one beaker into the contents of another and it bubbled up and over the edge of the beaker and created a small mushroom cloud. What chemicals can be used to achieve something like this and what are the safety precautions surrounding it? Sorry, I can't find the video but thanks in advance. -Haon 14:48, 8 October 2005 (UTC)

It would probably strongly depend on the conditions in the lab, including controlling drafts etc, so it might have just been luck. If you want the gas to fall below the top of the beaker, you'd want the gas to be cooler than the surrounding air, so probably good old dry ice in water would do the trick.

So at a normal room temperature, dry ice combined with water would create a mushroom cloud? -Haon 19:43, 8 October 2005 (UTC)

The main things needed for a visible mushroom cloud are:

1) The gas to rise must be much hotter than the ambient air temp.

2) The gas to rise must be visible.

3) The air must be relatively calm.

StuRat 04:40, 9 October 2005 (UTC)

So according to number one this couldn't be dry ice? Unless I'm terribly mistaken and dry ice mixed with water is much hotter than a normal ambient air temperature. -Haon 00:01, 11 October 2005 (UTC)

I would expect dry ice mixed with water to freeze the water, no mushroom cloud there. Dry ice can create a cloud of cold vapor, which sinks instead of rising, no mushroom coud there either, unless you are talking about an upside down mushroom cloud, where it falls to the floor then spreads out. StuRat 00:09, 13 October 2005 (UTC)

Water and dry ice make a vapor (Check out Dry Ice#Uses. I just don't know if this vapor could create this effect. -Haon 12:21, 13 October 2005 (UTC)

The vapor will be colder than air, so will sink, as previously stated. The only mushroom cloud I would predict would be an upside down one, also as previously stated. StuRat 14:24, 14 October 2005 (UTC)

Q1werty

Q1werty was here--Q1werty was here 15:38, 8 October 2005 (UTC)

You might be interested in the sandbox. AlMac|^(talk) 15:43, 8 October 2005 (UTC)

L-alanine Vs. Beta-alanine

What is the difference between L-alanine and Beta-alanine?--65.33.222.71 15:45, 8 October 2005 (UTC)

The position of the amino group on the carbon chain: see alanine and beta-alanine (although the latter doesn't have a structure diagram). Physchim62 17:25, 8 October 2005 (UTC)

timber joineries and defects of timber

can you please help with informative sites on timber joineries and defects of timber

       thanking you amrita

• Amrita,

You might wish to check our Woodworking and Joinery articles for a start. Capitalistroadster 07:22, 9 October 2005 (UTC)

Gradient Invariance?

What is gradient invariance?

Invariance means 'staying the same' and a gradient can mean lots of things, but usually means a gradual change or something that can be represented with an arrow. What's the context? DirkvdM 17:31, 8 October 2005 (UTC)

I think it means that if ${\vec {A}}({\vec {r}})\,$ is vector potential of a field ${\vec {v}}({\vec {r}})\,$, then so is the ${\vec {A}}({\vec {r}})+\,$ $\mathrm {grad} \,$ $f({\vec {r}})\,$.

Compuer Science - locks and operating systems

In computer science and operating systems, what is a lock? Is it the same as a semaphore? --HappyCamper 17:45, 8 October 2005 (UTC)

No, they're slightly different. A lock (also known as a mutex) is a logical construct -- you want sole access to a resource, so you "lock" it. Locks are usually implimented using semaphores, which are operating-system-supported atomic operations (and are fairly difficult to program with) →Raul654 17:48, 8 October 2005 (UTC)

Locks are often set by application software without dependency on anything in the operating system. For example if the "in-use" field of a particular customer order is "on" that means some set of programs from one user is in middle of updating stuff in the order (which could span multiple files or tables), and all other programs in the application have to stay out until the user is completed.

Program steps

1. Is flag ok for me to access?
   1. if not, then message user about situation, and exit attempt
   2. if Ok to access, then set flag "in use" (by me)
   3. at end of access to that order, set flag "available" for others to mess with that order
2. problem ... sometimes user access breaks (Windoze gets hung, communication link times out, someone kicks wall plug), the program ends abnormally, and the flag is never reset.

AlMac|^(talk) 02:38, 9 October 2005 (UTC)

Biology: Benedicts and glucose

May I have the balanced symbol equation for the reduction of Benedict's solution by glucose, please?

Wikipedia won't do your homework for you. See Chemical_equation#Balancing_Chemical_Equations to get started. — ceejayoz ^{★ .com} 03:31, 9 October 2005 (UTC)

Polarization of Electrons

In physics we've just been learning about the wave-particle duality of electrons and it made me wonder - can the wave 'side' of an electron be polarized like light? And if not why not, is it not a transverse wave, is particle physics just too abstract at this level for us to understand or what? ;) --BigBlueFish 19:54, 8 October 2005 (UTC)

Yes, electron beams can be polarized, and generally are in electron-positron colliders. It corresponds, if you're thinking about them as particles, to the spins all being aligned in one direction. (You can also think of polarized light as photons whose spins are aligned.) -- SCZenz 21:20, 8 October 2005 (UTC)

bees

bees can sting you. be careful. -Lethe | Talk 23:46, 8 October 2005 (UTC)

• No kidding! I got stung by one just the other day. He charged me 5 quid for a jar of honey! *boomtish*... thankyou, I'll be here all week. Try the veal! Noodhoog 14:05, 11 October 2005 (UTC)

• Our Bee article may be a good place to start. Capitalistroadster 07:25, 9 October 2005 (UTC)

A Dense Question

I understand that hot air rises and cold air sinks. I also under stand that the same convection forces are at work in the earth and cause magma plumes to rise up to produce volcano’s. Where it all falls apart for me is that as gravity is at work on hot air in that when it cools it pulls the cold, dense air, back to the ground. How does this work in the earth when the force of gravity diminishes the closer you get to the centre?--Eye 21:40, 8 October 2005 (UTC)

That's true, there is no gravity at the center of the Earth, and therefore no buoyant force to make the magma rise. But the magma that comes out of volcanos is not from the center of the Earth, but rather from the mantle, under the crust, where there is indeed gravity and buoancy.

-Lethe | Talk 23:33, 8 October 2005 (UTC)

I think that you have a fundamental misunderstanding of gravity. Gravity does not diminish the closer you get to the center of the earth, infact, in increases very rapidly. The force of gravity is inversly proportional to the square of the distance, which mean that if you go halfway down to the center of the earth, gravity will not be not only stronger, but 4 times as strong! gkhan 00:12, 9 October 2005 (UTC)

Sorry, gkhan, but that's all wrong. It's true that the Earth is sometimes modelled as a point mass with all the mass at the center. However, this model is only accurate when you are far from the center of the Earth, and preferably at the surface or above. However, if we insisted on using that poor approximation even when we were at the center of the Earth, the calcs would give us an infinite force of gravity, since our distance from the pt mass at the center would be zero. This would cause the Earth to collapse inward on itself into a black hole, leaving only those people behind who don't insist on using the pt-mass model when it isn't applicable, LOL. An accurate model would find the gravity vector between the person at the center of the Earth and each atom in the Earth, using the distance to each atom to determine the strength. All these vectors would then be added and would total zero, if an equal number of atoms were on each side. StuRat 04:18, 9 October 2005 (UTC)

You are ofcourse right. It's been a few years, I apologise :P gkhan 10:08, 9 October 2005 (UTC)

No prob, glad to help you shake off some of the rust on your physics memory. StuRat 16:10, 9 October 2005 (UTC)

Suppose we are walking along the inside of a hollowed out asteroid that is in perfect mass balance, not spinning, The total mass under foot is tiny compared to the rest of the mass ... the center of gravity is to be floating in the middle of the hollowed out space.

But center of Earth is different matter. Gravity has crushed the material of which the Earth is made to high density near center of earth. It is not hollowed out. AlMac|^(talk) 02:44, 9 October 2005 (UTC)

It would be more correct to say the forces of gravity would be balanced at the center of the Earth, hence there is no NET gravitational force. So, indeed, a person in the center of the Earth would be weightless. However, the immense pressure from all the material is believed to make the core of the Earth solid. Only the molten mantle between the core and the crust experiences convection, and, as noted previously, there is still considerable gravity at the mantle. StuRat 04:04, 9 October 2005 (UTC)

That’s a better way of putting it …there is no net gravitational force at the centre of the earth…which I presumes means that the mass of the earth above the point of centre pulls up in all directions causing the illusion of weightlessness of any object the happens to occupy the earths centre. Mmm…anti-gravity? :-) The force of gravity must exist then, like a crust around an object with mass like the earth. The maximum pressure must be exerted from near the surface and weaken towards the middle as the increase of mass above a given point pulls up on the mass below reducing the pressure. There should then be a neutral point be where the mass above a certain point would equal the mass below. A sort of gravitational boundary layer and this point would be determined by mass not size, i.e. that point would not be equal distance from surface to centre. Would this be where the iron core begins, and if so could the iron core be colder than people expect if the pressure on it is weakened by lower gravitational forces? --Eye 19:49, 9 October 2005 (UTC)

Well, since the iron at the center is more dense, you would still expect the point of zero net gravity to be very near the geometric center of the Earth. I would also expect the iron core to be at least at hot as the material above it, since the heat has no way to dissipate, other than up through the Earth's surface. StuRat 23:58, 12 October 2005 (UTC)

Quote about solipsism involving Bertrand Russell

On the page Talk:Solipsism there is mention of a quote I've been looking for for some time. I recall quite clearly reading just a few months back about a telegram that a female logician sent to Bertrand Russell that said something very like "Have converted to solipsism. Am enjoying it immensely. Don't understand why more people don't do the same." Unfortunately, I can't find this on Google, Wikipedia, or any books I have in the house. Can anyone confirm/deny? George

I typed "betrand russell" solipsism into google and found this:

Bertrand Russell was giving a lesson on solipsism to a lay audience, and a woman got up and said she was delighted to hear Bertrand Russell say he was a solipsist; she was one too, and she wished there were more of us. - Beyond Reductionism

-- W. H. Thorpe

was that it? -Lethe | Talk 23:29, 8 October 2005 (UTC)

That's the thing. I can find references like that - to a layperson saying something dumb - but I have the clearest memory of reading about it in the joke telegram context. I do thank you for your help, though. George 00:38, 10 October 2005 (UTC)

limits in topology versus limits in category theory

Is there a way that you can interpret the limit of a sequence in a topological space as a limit of some appropriate functor between some categories? -Lethe | Talk 23:16, 8 October 2005 (UTC)

Identifying some fish and seaweed species

It would be great if someone could tell me what species some or all of the following are:

All were caught/picked off the coast of central Algeria. - Boualem 00:12, 9 October 2005 (UTC)

Genotypes

Here is the situation: A brown-eyed man whose father was brwn-eyed and mother was blue eyed married a woman whose father and mother were both brown-eyed. The couple has a blue-eyed son.

For which of the individuals mentioned can you be sure of the genotypes?

What are their genotypes? What genotypes are possible for the others?

Thank you for your time in advance

Well I'll get you started on your homework! The trait for blue eyes in humans is recessive, so any blue eyed-person must be bb in genotype. Brown-eyed people can be homozygous or heterozygous for the dominant gene B. Take it from there! Physchim62 00:41, 9 October 2005 (UTC)

Alcohol

Why is alcohol so fattening? ♥purplefeltangel ^(talk) ♥ ^(contribs) 03:18, 9 October 2005 (UTC)

It isn't. Non-alcoholic beer is just as fattening as alcoholic beer, for example - it is the other stuff in the drink. Lots of carbohydrates in beer. — ceejayoz ^{★ .com} 03:29, 9 October 2005 (UTC)

I might want to add a proviso to the remark above. Alcohol does have appreciable caloric content all by itself, but the total calorie content depends quite a bit on the beverage. Vodka is essentially pure alcohol (~40%) and water; it will run you about 65 calories per fluid ounce. Beer depends somewhat on how it is brewed. Stouts like Guinness get only about a quarter of their calories from carbohydrates; most of the rest is from alcohol. Sweeter lagers can draw up to about half of their calories from carbohydrates—they contain more sugar. Irish Creams like Bailey's are loaded with sugar and cream; only about a third of the calories are from alcohol, with the balance being from fat and carbohydrates. TenOfAllTrades(talk) 04:34, 9 October 2005 (UTC)

(after edit conflict)

In virtually all plants and animals, glucose is transformed into energy in three steps: glycolysis, the citric acid cycle and oxidative phosphorylation. Yeast cells produce alcohol from glucose when there is little or no oxygen: they only use glycolysis to do this, and gain much less energy as a result, only 6% of the energy released by the three steps together. When the alcohol is consumed by another animal, it is broken down by the citric acid cycle and oxidative phosphorylation: the animal which consumes the alcohol is gaining the energy which the yeast could not obtain from the sugar, ie the other 94%. Hence drinking alcoholic drinks is almost as fattening as drinking sugar solutions... Physchim62 03:37, 9 October 2005 (UTC)

Um, can you explain that in plain English please? ♥purplefeltangel ^(talk) ♥ ^(contribs) 03:43, 9 October 2005 (UTC)

Sure, the body converts alcohol into sugar, so it's just like you drank a glass full of sugar-water, which would also be fattening. StuRat 03:53, 9 October 2005 (UTC)

When turn sugar into carbon dioxide and water, you release 36 "units" of energy. When the yeast turns sugar into alcohol, it only releases 2 "units" of energy. When you drink the alcohol, your body releases the other 34 "units" that were present in the sugar. The Calories in our food are also measures of the energy released by our body when we digest the food: if we release more energy than we need, we store it as fat.... So alcohol contains almost as much energy as sugar, even if it doesn't taste sweet, and so is at least as likely to make us put on weight. Is that any better for you? Physchim62 03:51, 9 October 2005 (UTC)

Or, to put it another way. The yeast, being suck in an environment with no oxygen (by our design since we want the alcohol) relies on this trick where they can get a tiny amount of energy by doing a metabolism that results in alcohol as its end product. They do this because a little energy is better than starving to death. Later, we drink the stuff and we are able to extract the rest of the energy that the yeast was not able to get to. Since the yeast gets only about 6% of the potential, it is a good way to fatten oneself up. Qaz ^(talk) 04:00, 9 October 2005 (UTC)

Thank you. ^__^ ♥purplefeltangel ^(talk) ♥ ^(contribs) 05:08, 9 October 2005 (UTC)

I seem to remember learning in 9th grade health class that when you're drunk, your metabolism slows and converts existing stores to fat at a higher rate. This might also contribute. -Lethe | Talk 05:10, 9 October 2005 (UTC)

This is the reason I remember too, due to the liver having to process the alcohol. Dysprosia 11:29, 10 October 2005 (UTC)

I would also add a lifestyle factor. The heavier drinkers I know tend not to be the people that go jogging or to the gym. --bodnotbod 00:59, 13 October 2005 (UTC)

Tests for Lymes Disease strain idenification

I am looking for the name of a test for strain idenification to idenifty where I got Lymnes. Can you help with this test name?

Thanks, 04:52, 9 October 2005 (UTC)65.7.78.21

• Our Lyme disease articles that the two serological tests for that disease are the Western blot and the ELISA test but neither tests are reliable indicators. Polymerase chain reaction tests are used but can show false-negatives. I would speak to your doctor about tests. Capitalistroadster 07:35, 9 October 2005 (UTC)

Excel problem

I accidentally did something to my excel options (I have no idea how) and now when I press the up/down/left/right arrows on my keyboard, the view scroll as opposed to what normally happens, which is the current cell moving. Does anyone know how to change the settings back. The version is Excel 2002. Thank you :-) Akamad 04:54, 9 October 2005 (UTC)

Sounds like you have Scroll Lock turned on, IIRC. I don't have Excel handy to verify that though. — File:Ontario trillium sig.pngmendel ☎ 04:59, 9 October 2005 (UTC)

mendel is right, I just tested it out. Turn scroll lock off to fix.--inks^T 05:00, 9 October 2005 (UTC)

Thanks all. That did the trick. Akamad 05:01, 9 October 2005 (UTC)

It says something about the obsolescense of the Scroll Lock key that a person inadvertently using it for the purpose for which it was designed sees that usage as a problem. Down with Scroll Lock! Brian Schlosser42 16:45, 10 October 2005 (UTC)

Swarovski Crystal vs Teeth

Just a question. I recently bought my girlfriend a little expensive lump of Swarovski Crystal carved into the shape of a rabbit. If we get a real rabbit, put the crystal into it's cage, and the rabbit chews on the crystal, will the crystal be scratched? I'm thinking Silicates vs Calcium compounds, but have no idea of the answer. Any thoughts appreciated. :) --inks^T 05:03, 9 October 2005 (UTC)

Looking at the Mohs_scale_of_mineral_hardness we see that glass has a hardness of 6 or 7. Hydroxylapatite, the main constituent of enamel, has a hardness of 5. The rabbit, however, could break the glass with a sudden bite rather than slow scratching. --Borbrav 05:38, 9 October 2005 (UTC)

Indeed. Many people do not realize for example that although diamonds resist scratching better than any other common material, they are nonetheless vulnerable to breaking by the application of surprisingly little force. It is a good thing too or they would be much harder to cut into pleasing shapes for our Bling Bling. Qaz ^(talk) 05:42, 9 October 2005 (UTC)

Thanks guys :) --inks^T 07:43, 9 October 2005 (UTC)

general question

what is the reason for ice vessels are not licked?

Because your tongue would freeze to the side. Gdr 11:41, 9 October 2005 (UTC)

This usually only applies to materials with high themal conductivity, like metal. Materials with low themal conductivity, like styrofoam, could be very cold before licking them would freeze your tongue to them. StuRat 17:00, 9 October 2005 (UTC)

Seed Law

What is seed law?

In what context do you mean seed? Could you provide a little more information so that someone can answer you more specifically? Then again, a search for "seed law" returned a considerable number of hits, quite a few of which appear to be related to civil law in the United States. Rob Church ^{Talk | FAD} 16:06, 9 October 2005 (UTC)

Stomach acid

I read in my biology book that stomach acid is supposed to kill bacteria, then why do people get food poisoning if the acid is supposed to destroy all bacteria?

Because the bacteria can spread to all sorts of places before they even reach the stomach. - Mgm|^(talk) 11:29, 9 October 2005 (UTC)

There are several ways this can happen:

• Some kinds of food poisoning are caused by exotoxins, poisonous substances excreted by bacteria before you eat them, for example botulin produced by Clostridium botulinum.
• Some bacteria, for example Staphylococcus aureus, produce toxins in the stomach before they are killed by stomach acid; these toxins are absorbed by the intestine.
• Some other bacteria have mechanisms that allow them to survive the acidic environment of the stomach. Escherichia coli can survive for several hours at pH 2, long enough to pass through the stomach. Some Salmonella species attach themselves to food particles and thus get some protection from the acid.
• Helicobacter pylori can survive indefinitely in the stomach (causing peptic ulcers). It survives by screwing itself into the stomach wall and excreting urease, which partially neutralizes the acid in a small region surrounding the bacterium.

Gdr 11:53, 9 October 2005 (UTC)

...And not all food poisoning is bacterial (though I suppose this is a rarer case). See, for example, the cheese fly, whose maggot burrows into cheeses and preserved meats, survives stomach acids, and causes serious intestinal distress. Bunchofgrapes (talk) 22:04, 10 October 2005 (UTC)

Quotation Marks in Word

How should I force my MS Word to show “” as quot. marks instead of »« when Smart Quotes option is turned on?

Probably need to set it to English rather than French somewhere... either for the whole program, or for the text-style you're using (and don't forget: if you copy/paste anything with those quotes onto web-pages/wikipedia, then they will appear as invalid characters) Ojw 13:11, 9 October 2005 (UTC)

Whenever I switch between language keyboards I find this to be a persistent problem. For example, my main keyboard is in English, so when I start a document it does the correct "English" style smartquotes. However if at any point I switch to another language (in this case, Russian), suddenly I get only Russian smartquotes (as you have above) even after I switch back to the English keyboard. It's very irritating and I couldn't find any way around it, so I just disabled Smart Quotes completely. --Fastfission 14:48, 9 October 2005 (UTC)

I used to work in a computer lab where Word would do stuff like this often. I know there is a "Select Language" function somewhere in Word that will let you switch it back to English, but I can't recall how to access it. Try searching Word's help files for "language." Garrett Albright 15:58, 9 October 2005 (UTC)

Skin Breathing?

According to the Bond Film Goldfinger, painting someone with Gold kills them by stopping their skin breathing. Surely, if this was true, you would suffocate every time you went swimming? smurrayinchester^{(User), (Talk)} 12:52, 9 October 2005 (UTC)

On the one hand, yes, the Bond film is nonsense. On the other hand, there is a lot of oxygen suspended in water... Shimgray | talk | 13:30, 9 October 2005 (UTC)

Humans don't have gills, so this oxygen is largely useless to us. Rob Church ^{Talk | FAD} 16:07, 9 October 2005 (UTC)

If the paint were thick enough to interfere with sweating, then it might lead to hyperthermia (heat stroke). Gdr 15:26, 9 October 2005 (UTC)

• Yes, it interferes with sweating and may cause hypothermiahyperthermia, but under controlled situations it's hardly lethal as proven by the MythBusters. There's also a urban legend that the lady playing the gold-painted secretary died during filming. While it was quite uncomfortable she lived to do at least six more films and was available for a short interview with the MythBusters to show this particular legend was nonsense and she was still very much alive. - Mgm|^(talk) 17:53, 9 October 2005 (UTC)
• Snopes has a good write-up. --jpgordon∇∆∇∆ 17:54, 9 October 2005 (UTC)

The other question I have is 'If Gold is so expensive, would painting her with a pot of matte emulsion from B&Q be as effective as well as much much cheaper', but I guess he just wanted to show off. smurrayinchester^{(User), (Talk)} 20:00, 9 October 2005 (UTC)

Pucefinger just sounds wrong. And as for Brownfinger... --bodnotbod 01:04, 13 October 2005 (UTC)

How to calculate reliability

Reliability is a qualitative property, not a quantitative value, so it can't be directly calculated. What are you trying to find the reliability of? Depending upon the type of the information/source, you may need to choose from a number of methods. Rob Church ^{Talk | FAD} 16:10, 9 October 2005 (UTC)

No, there are plenty of quantitative measures of reliability (in one of its senses): see failure rate for a discussion. Gdr 16:51, 9 October 2005 (UTC)

One can use the historical reliability of a product to estimate future reliability, but this is somewhat limited by constant changes to the product line. Defects may be repaired, which may increase reliability, while new features may be added, which tend to decrease reliability.

In some cases, more direct ways to estimate the life of a product are available. For example, tires have a rated life (in km/miles) based on how quickly the rubber is expected to wear away with normal use. This type of estimate may be better for a new product, with no historical track record.

StuRat 16:54, 9 October 2005 (UTC)

Reliability of what? A measurement? In a laboratory or something like a survey? If you speak of calculation that suggests you mean something scientific. But even then there are loads of things that can be (un)reliable. DirkvdM 17:19, 9 October 2005 (UTC)

IBM hardware has a concept mean time to failure which is when they expect it to fail, on average. We had a hard disk with a mean time to failure of 13 years. When it began to get close to that old, I was trying to explain to management what that meant, without much success. Guess what? It was lucky 13 years old when we experienced a hard disk crash. AlMac|^(talk) 20:42, 10 October 2005 (UTC)

Gravitational force as caused by the electromagnetic force

A few years ago, I tried to explain gravitational force as caused by the electromagnetic force. I got a force proportional to distance to-the-power minus six (instead of the required minus two). Will the derivation be of any use in making a Unified field theory? —Masatran 14:37, 9 October 2005 (UTC)

The unification of gravity and electromagnetism has been tried before; see Kaluza-Klein theory. The results proved to be less than satisfactory, in the end, but they might be part of the solution what has turned out to be an exceedingly difficult problem. -- SCZenz 17:24, 9 October 2005 (UTC)

Converting image files

I have a Windows 98 computer. In Windows Explorer, is it possible to convert Microsoft Word files to other file types, and if so, how? HyperHobbes 15:53, 9 October 2005 (UTC)

In general, to convert files from one format to another, open them with an application which can read them (Microsoft Word, in your case), then either do a File + Save As or a File + Export and select the type of output file desired. StuRat 17:28, 9 October 2005 (UTC)

If you have a Word document, but not the program Word itself, you should still be able to open the file (then File + Save as at StuRat said) with WordPad.--Commander Keane 08:48, 10 October 2005 (UTC)

Well, this might seem silly, or impossible, but what I am trying to do is convert a Word image into a PNG. Is this possible? HyperHobbes 15:41, 13 October 2005 (UTC)

You should be able to. I don't have Microsoft Word but I was able to convert a .txt to .png with Notepad. Robmods 18:13, 13 October 2005 (UTC)

Take a screenshot, save as PNG. Ojw 17:29, 14 October 2005 (UTC)

How do I take a screenshot? HyperHobbes 16:19, 15 October 2005 (UTC)

How do I enable BitTorrent in Opera 8.5?

Does Opera 8.5 have BitTorrent disabled, or is it included at all? --pile0nades^{talk | contribs} 16:46, 9 October 2005 (UTC)

The BitTorrent support was disabled on the final release of 8.5, but it's functional on the 8.10 tp2 release. See [10] ☢ Kieff | Talk 20:29, 9 October 2005 (UTC)

I already tried this one but it has ads. Is 8.10 TP2 newer than 8.5? --pile0nades^{talk | contribs} 22:07, 9 October 2005 (UTC)

No it isn't. You could always stick with 8.5 and wait until the next version of Opera, where all these features will be present. Also, the BT support in Opera wasn't so good, apparently, and it was just experimental. I think for next version you can expect something solid. Meanwhile, stick with a torrent client. ☢ Kieff | Talk 08:58, 10 October 2005 (UTC)

Get Firefox! ♥purplefeltangel ^(talk) ♥ ^(contribs) 20:59, 9 October 2005 (UTC)

Firefox doesn't support integrated BitTorrent at all, and probably won't for a long time. I'm using it now anyway though. --pile0nades^{talk | contribs} 22:07, 9 October 2005 (UTC)

Sorry, I just hate Opera. :D ♥purplefeltangel ^(talk) ♥ ^(contribs) 23:23, 9 October 2005 (UTC)

Why? Jealous? ^^ ☢ Kieff | Talk 08:55, 10 October 2005 (UTC)

Now, now boys, no fighting. We all know Firefox is better, so we shouldn't let this get ugly :P gkhan 15:59, 10 October 2005 (UTC)

Based on what you think it's better? Certainly not on security, speed, resource management, user interface, functionality and features, I'm sure. ;) ☢ Kieff | Talk 06:13, 11 October 2005 (UTC)

sending/receiving faxes online

Hi I was wondering if there was a free service or a very cheap one that would enable me to send a receive faxes online. I would prefer something that would let me goto "file" and then "print" and let me send a fax that way, similar to printing, but would ask me what phone number I would like to send it to. Something similar to efax.com. I used to use that, but now they want money.

Thanks

You can send (but not receive) for free via The Phone Company if the number you want to send to is covered by them. It works via email or their web site, not by "printing" the fax to them, but it is free. -- AJR | Talk 22:46, 9 October 2005 (UTC)

Actually, there are some clients for TPC that do act as print drivers. --WhiteDragon 18:52, 11 October 2005 (UTC)

If you just want to send a fax from your computer then all you need is a fax modem. Most of these work by having you print your document using a special print driver, then dialling another fax machine and sending just like a normal fax machine. That's not really "sending a fax online" though, as it doesn't involve the internet.. To do that you'll need some kind of web-to-fax or email-to-fax gateway service such as the one AJR named above. Typically with these kinds of services you get what you pay for.. Free ones are often limited in some way such as the amount you can send per week, or appending messages to the end of your fax. Noodhoog 14:21, 11 October 2005 (UTC)

For receiving faxes, [11] has a free account, where you get a fax number (but can't specify the area code) for a limited number of faxes that get delivered to your email inbox. --WhiteDragon 18:52, 11 October 2005 (UTC)

All the KDE applications have a "Send to fax" option in the printing menus, which I think answers the first question. Assuming you have an unused modem connected to your computer (and to a phone line), that will send the fax.

If you have a Mac, it's very similar. In the print menu, select "Fax PDF" instead of choosing a printer. To receive, tick "receive faxes on this computer" in the "Print and fax" settings window, and specify where to save them.

It should be similar for Windows, but someone else will have to tell you where the options are. Ojw 20:38, 11 October 2005 (UTC)

energy from the seatemperature

I recently heard that an average hurricane unleashes an amount of energy equal to five times the worldwide annual energy consumption of humans (still can't believe it - did I misunderstand?). I understand that that energy comes from the temperature difference between the water and the air. So naturally I thought if this energy could be harnessed. There are two obvious advantages, one being the energy source and the other being the prevention of hurricanes. The Ocean thermal energy conversion article is about temperature differences between different parts of the water, which is something different (or is it really?). Would something like this be plausible? DirkvdM 18:12, 9 October 2005 (UTC)

I've thought about this topic myself. There is a great potential there, but actually developing an efficient mechanism to exchange heat between the air and water is quite a difficult problem. The main issue is that the temp diff is so gradual and spread out over such a wide area. If we had a thousand degree temp differential of two dense fluids right next to each other, it would be easy to generate energy from this, but a 5 degree difference over two fluids (one of which is a sparse gas) more distant from each other is another matter. But, if you can think of such a device, your fortune will be made ! StuRat 20:36, 9 October 2005 (UTC)

The surface water could also be cooled by using cooler water from below the area which receives most of the thermal energy from the Sun, but this is also impractical under today's technology. Perhaps instead of waiting until the water is over-warmed, a more proactive approach is in order. Large areas of the ocean could be covered by solar collection panels, to prevent the water from becoming warm, but the low efficiency and high cost of solar cells makes this scheme impractical, too. A newer technology, like genetically engineered microbes that live in seawater tanks, extract sunlight energy by photosynthesis, and release methane gas as a waste product (which we would harness for energy). might be a better way to go. StuRat 21:08, 9 October 2005 (UTC)

Better make those microbes sterile -- I'd hate to imagine what'd happen if they were released into the real ocean and then started reproducing… Garrett Albright 18:19, 10 October 2005 (UTC)

The energy from the sun that warms the oceans is currently used to power vast ocean curents that help equalize Earth's temperatures, create hurricanes and other weather patternes, and cause vast amounts of fresh water to be distributed over the face of the earth in the form of rain and snow. The energy is not going to waste. WAS 4.250 22:27, 10 October 2005 (UTC)

There's a theory about dropping ice crystals or other chemicals from aircraft into the tropical storm from above. The crystals or other chemicals then interact with the wet air to have a chemical reaction to transfer energy to or from the storm. The idea is to try to steer it away from land. There's been experiments with this. I do not know the outcome.

There's places in the world where they get energy from the sea by tapping the tides. Consider an estuary that comes about because of a major river and how the coast to the sides of it happen to be topographically. As the tide comes in, it gets squashed sideways, so as to be quite high. Well put a dam there that drives turbines for electricity, then when the tide goes out, have the turbines going in the other direction.

Fresh water can also be got from sea water through desalination (spelling?).

There's a school of thought that if we humans do a lot of that, it could mess up the natural temperature ranges of the sea, thus impacting the ocean currents, and doing real damage. AlMac|^(talk) 06:26, 11 October 2005 (UTC)

Not sure quite how relevant this is, but there's a guy developing a system to generate power from artificial tornadoes - The Economist recently ran an article on it Noodhoog 14:30, 11 October 2005 (UTC)

GASES

HELLO JUST GOT A QUICK QUESTION ABOUT GASES, WHAT GAS DISSOLVES IN WATER AND WHY82.26.64.128 18:55, 9 October 2005 (UTC)

Lots of gases dissolve in water. Carbon Dioxide for example. But don't ask homework questions here and turn off your CAPS LOCK. smurrayinchester^{(User), (Talk)} 19:58, 9 October 2005 (UTC)

what is the SI unit used to measure time?

You'll be wanting to look at our article on SI. TenOfAllTrades(talk) 21:30, 9 October 2005 (UTC)

also Time#Present day standards --JWSchmidt 21:32, 9 October 2005 (UTC)

It will only take you a second to find the answer there. StuRat 21:38, 9 October 2005 (UTC)

Is it just me or is Mother Nature really pissed off?

• Three hurricanes went across Florida last year.
• Mt. St. Helens threatened to erupt.
• Thousands were killed by the Indian Ocean earthquake and subsequent tsunamis.
• Hurricanes Katrina and Rita tore up the Southern U.S. and areas south of that.
• A couple thousand people were killed in Guatemala due to a mudslide because of Hurricane Stan. They'll probably declare one town a mass grave since the inhabitants are under 40' of mud.
• And then there's the earthquake that hit Pakistan/India/Afghanistan with 20,000+ dead there too.
• I think I'm forgetting something from last year but I can't recall just what.

So, is it just me or does this seem like a lot of death, destruction, and mayhem caused by natural disasters for just two years? Can anyone point out another relatively short period of time where a series of events have taken place that have done similar damage? I realize that The Black Plague or possibly the devestation of Pompeii killed more but they had just one root cause. These events have had different root causes and have been more spread out. Or if I'm being naive, just let me know... :) Dismas|^(talk) 05:42, 10 October 2005 (UTC)

The exponential growth of global warming contributes to many of these disasters one way or another. --Ballchef 06:21, 10 October 2005 (UTC)

The whole global warming discussion is controversial, and I am not sure about the mechanism where is contributes to earthquakes.

Also, population pressure forces large numbers of people to live in areas subject to earthquakes, mudslides, hurricanes etc and poverty means they can't afford to build earthquake-proof buildings or flood defences. And the global media strengthens the recency illusion. You might want to see our list of disasters and the pages linked from there. Gdr 07:34, 10 October 2005 (UTC)

After edit conflict:

I don't know how many got killed in Pompei, but it can't have been too many because the population then was so much smaller than it is today that it must have been a small town by today's standards. And the death toll of the black death was immense, but the Spanish flu killed between 25 and 50 million people in one year. Which is one cause of the great death tolls. There are just more people to get killed. Another thing is that we hear more these days because the media are more present and more info on international affairs. Still, they're regionally biased. Look at your list. Out of the 9 disasters you mention 6 are in the US. Let me guess. You're from the US. Which is why those disasters get more attention than they deserve (also in Europe). Take Katrina. On a worldwide scale that was peanuts. That sort of thing happens regularly in Bangladesh.

About the overall picture, I really don't know if there have been many more disasters in the lat few years, but either the increase would have to be enormous (say ten times normal) or there would have to be a trend over a longer period to draw any statistically valid conclusion that something is going on.

Ballchef says many of these things can be attributed to global warming. In the cased of the Asia tsunami, St Helen's and the earthquakes, there's no link. But there are reports that hurricanes are becoming more frequent and occurring in places where they shouldn't occur or not at that time of year. But that's also nothing compared to the disaster we're facing with the shift in climate zones due to global warming. Crops will no longer grow where they used to. Which will lead to mass starvation. Luckily, not so much for us, more in poor countries. But it will wreck our economies as well. So we will just be less filthy rich.

In the nearer future, we can expect a pandemic of the chicken flu. That's not a question of if but of when. And it's going to be soon. With an increased population compared to the Spanish Flu it could kill more. Let's hope that the increase in technological knowledge will give us a better chance to prevent that. DirkvdM 07:48, 10 October 2005 (UTC)

Shut up you and your science!!! It's the end times coming!!!

Uhm, seriously, this was due to happen. Like it has been mentioned, global warming and super population just makes it all more tragical. Besides that, estimatives about cyclic catastrophes put this particular decade (actually, this half-century) on range of several large ones. Scientists say that soon San Francisco and Los Angeles will suffer from a massive earthquake while a bunch of volcanoes erupt worldwide, and a gas explosion happens once again on the bottom of that lake in Africa. A huge piece of earth will also collapse on that other island I forgot the name, and that will create a ultra massive tsunami. Oh, and of course, the martians arrive. Bad luck, perhaps. ☢ Kieff | Talk 08:53, 10 October 2005 (UTC)

1. An earlier generation thought AIDS was a terrible disaster.
2. A later generation will think the use of WMD by terrorists is terrible.
3. Don't forget super volcano under a major national park.
   1. and the aftermath of a giant rock from space hitting our planet ... we have the scientific know how to protect humans from what wiped out the Dinosaurs, but not the political will.
4. How come the USA is so inept when it comes to fighting wild fires out west?

   Wildfires in the western US are a normal part of the ecology there, due the dry climate and frequent lightning storms. See our wildfire article for an explanation of why trying to put them out is a bad idea. Gdr 11:58, 10 October 2005 (UTC)

5. Then there are serious consequences of the ozone hole in the Southern Hemisphere, which not get much press in the Northern.
6. Global warming and Global cooling are on a long term cycle ... consider the Vikings crossed North Atlantic Ocean at same latitude as the Titanic but had no problem with ice bergs because the Vikings were in a period of global warming, and the Titanic in a period of global cooling.
   1. Albert Gore had a book on history of environmental changes which talked about the Year of no Summer in Europe that led to an agricultural calamity that was the forerunner to the Black Death.
7. While Hurricane Katrina was a natural disaster, there was a lot of things that mankind failed to do in the mitigation of emergency planning that contributed to making the disaster much worse than it might have been otherwise.
   1. The National Hurricane Center, and other Weather Professionals have been tracking patterns for decades. They show that there are like 40-50 year cycles in frequency of tropical storms. An "inactive" cycle can still have a really bad one like Hurricane Andrew, so you always need to be prepared, especially in Florida, which seems to get more Hurricanes than the rest of the world combined. Right now we are in the early stages of an "active" cycle, meaning in the next 10 years or so they will get more frequent, which will include more of the very bad ones.
      1. The Army Corps of Engineers is using data from earlier "inactive" cycle, that says 1 chance in 500 per year, that New Orleans could be hit by a Hurricane worse than Category 3, so that's all we need to protect the city from.
      2. Millions of dollars came from the Federal government to pay to make the levees able to protect the city from a Category 3 Hurricane, but the local government found other more important things to spend that money on.
      3. Building a city below sea level seems foolish ... what's the practicality of rebuilding on higher land ... raising the land before the rebuilding
      4. Due to global warming, sea level world wide is rising slowly, so New Orleans is a precursor to what all coastal cities will be facing in the next 50 years. The vast majority of them do not have protection as "good" as New Orleans.
   2. Government knew from past Hurricanes, and US Census, that something like 1/3 of the population was too poor or disabled to voluntarily evacuate, plus there was a significant other minority that would never cooperate with a voluntary evacuation, choosing to ride out any storm because they did not understand the Category system, and also feared looters
   3. City of New Orleans had an evacuation plan, that they failed to implement
   4. Widespread Looting and Mayhem turns out to have been an Urban Legend mass produced by the News Media, that led to significant delays in getting help to New Orleans, and some ugly incidents against people trying to flee flooded areas
8. The news media has a talent for painting every humanitarian disaster as the worst ever in history, which means that a lot of people do not believe it when it really is bad.

AlMac|^(talk) 09:41, 10 October 2005 (UTC)

I don't want to put a downer on the previous upbeat answers but hang around until the next big comet impacts the Earth and wipes out 99% of life on earth. After many more big comet strikes on our planet, the Sun will eventually turn into a Red Giant and you can say goodbye to the world. That's if our solar system does't as some point get too close to a black hole and get swallowed. Actually I think that mother nature seems quite benign at the moment. Majts 09:48, 10 October 2005 (UTC)

SO... Does human population/development/existence have any effect of the frequency/size of earthwuakes, or is it all natural? --Ballchef 00:00, 11 October 2005 (UTC)

There is some speculation that the weight of oil deep down, then removed by oil drilling, can have an effect on the stability down there. AlMac|^(talk) 03:44, 11 October 2005 (UTC)

I really doubt that the tectonic plates care much about the featherweight that is human civilisation crawling on its surface.--inks^T 01:29, 11 October 2005 (UTC)

In the Netherlands we've got a problem with the ground sinking where gas has been pumped out, and that can lead to minor earthquakes. DirkvdM 17:48, 11 October 2005 (UTC)

When some part of our planet is unstable, can terrorists help trigger trouble, like perhaps setting of WMD in the side of a Volcano, letting the lava flow out there, and the change in pressure, perhaps trigger an eruption. Or is this speculation we not want to encourage? AlMac|^(talk) 03:43, 11 October 2005 (UTC)

I'm sure that would work...but if I had such a WMD I'd stick it in downtown Manhattan for greatest effect. :) --inks^T 06:05, 11 October 2005 (UTC)

This was also the theme of a James Bond film, although that's of course no guarantee that will work. But it sounded fairly plausible. DirkvdM 17:48, 11 October 2005 (UTC)

Scientologist! All you need to do is pile bodies 100-deep by a volcano, and trigger it with a nuclear weapon. Then all the dead bodies become Operating Thetans... Ojw 21:32, 15 October 2005 (UTC)

Geesh, given the diversity of all those folks (above) that are allowed to edit an encyclopedia there's no wonder about what makes this project so great. --hydnjo talk 01:19, 16 October 2005 (UTC)

Carbonic Acid

Please can anyone tell me what is the chemical mechanism for the formation of carbonic acid (H2CO3), from its constituents CO2 and H2O is? Thankyou, Ben

--163.1.209.120 07:34, 10 October 2005 (UTC)

• I'm not sure how my answer disappeared, so I'll say it again. Carbon dioxide and water form a small amount of H2CO3 when CO2 dissolves into the water. - Mgm|^(talk) 10:54, 10 October 2005 (UTC)

Under pressure (which is what soft drink maker do) more CO2 will dissolve.

Toxicity of cured epoxy

I've been sculpting with epoxy for a few weeks now and my cat just ate a tiny ball of epoxy (much less than 1 cm in diameter). The epoxy's been cured for a few days already.

I'm not sure how much of a hazard this can be to a cat. I'd suppose that cured epoxy is less dangerous (less reactive), but I don't know shit about toxicity of this substance when ingested, especially by an animal. Should I be very worried or what? ☢ Kieff | Talk 08:41, 10 October 2005 (UTC)

It says it's very toxic at the bottom of this page. Although if cured it *may* pass through the system without ingesting. Usual disclaimers: consult a vet and the epoxy packet for any warnings given. Majts 10:13, 10 October 2005 (UTC)

Actually, I just found the little ball in question behind the desk, so it's ok. :) ☢ Kieff | Talk 14:37, 10 October 2005 (UTC)

Orginal Investor In Both

Who was the orginal investor in both Microsoft and Apple Computer companies?

MANY THANKS Paul Autin, CSET Cantonment, Fl 32533-7510 [email address removed]

Please don't post your email address on the Reference Desk unless you want to receive spam. Until each company "went public," both Microsoft and Apple Computer were private companies owned by and invested in by their owners. See each respective article for more on each company's history. Garrett Albright 18:07, 10 October 2005 (UTC)

How much water would a person have to drink before it killed him?

Just curious. --Maxamegalon2000 17:32, 10 October 2005 (UTC)

The LD-50 of water is something huge - on the order of half your body-mass, I believe. Messy death, too, but very difficult to actually achieve - generally the body's reflexes kick in and stop you consuming more. It's a lot quicker by drowning! Shimgray | talk | 17:47, 10 October 2005 (UTC)

• Leah Betts supposedly died from drinking too much water, but according to that article it was more due to drinking too much water in too little time (7 litres over 1.5 hours). --Bob Mellish 17:59, 10 October 2005 (UTC)

Drinking enough to cause seizures and unconsciousness (water intoxication) is not so rare. There are plenty of case reports in the medical literature, including a few with fatal outcomes. The amount to induce unconsciousness varies by body size, ambient conditions, and starting degree of hydration, and whether alcohol or various salts or sugars were in the water, but would be much smaller than half your body mass, more like 5-10 liters of pure water chugged in rapid succession for an adult. alteripse 18:04, 10 October 2005 (UTC)

There are many factors involved. It may vary, but in a person of low blood-electrolyte concentration, the loss of necessary electrolytes can cause cellular damage, especially in the muscles and vital regions of the brain. This dilution will complicate the body's normal physiological functions, which depend on many chemicals dispersed through the body. Another may be the enormous bloating. Too much water will raise blood volume and will increase blood pressure. That can cause further problems in the cardiovascular system, making it difficult for the heart to help the blood nourish and for the blood to nourish the body.--Screwball23 15 October 2005 7:59PM

Having poked around, it seems I was remembering "enough to start physically destroying cells", as opposed to "enough to cause shock and unconsciousness, then potential death". Shimgray | talk | 18:12, 10 October 2005 (UTC)

This site says the pledge at Chico State drank 5 gallons, but there were other factors involved as well. User:Zoe|^(talk) 04:10, 13 October 2005 (UTC)

Pharmacy Compounding

Hi, I was wondering if there was a free web site that has compounding ingredients and recepies. I know there are pay sites, but they are very very expensive.

Thanks

same system call interface

Hi,

I am looking for the answer for the below question.

What are the advantages and disadvantages of using the same system call interface for manipulating both files and devices?

Thx

BK

--68.239.159.120 19:01, 10 October 2005 (UTC)

Is this question for your homework? Notinasnaid 19:10, 10 October 2005 (UTC)

Yes

You might like to note two things:

• The bit at the top of this page that says "do your own homework".
• This book by Andrew Tanenbaum. If your library has it, borrow it. --Robert Merkel 01:01, 11 October 2005 (UTC)

carat

what is the measuement called that can measure a carat that has the description of unit of weight for gemstones?

see Carat (mass). It probably answers your question . - Nunh-huh 02:56, 11 October 2005 (UTC)

Propagation speed of a tsunami wave

The propagation speed of a tsunami wave is , from what I have read , of the order of 200 to 500 km/h .

What are the factors which determine the actual speed ? Is there somewhere a description of an appropriate model which describes that wave ?

Any help will be appreciated , thank you .

There is a brief mention of the physics involved in a tsunami in our article about tsunamis (sp?).--inks^T 22:04, 10 October 2005 (UTC)

If you're a genius, look at this article and the references gkhan 22:22, 10 October 2005 (UTC)

If hazy memory of first-year physics serves, the dominant factor controlling speed of propagation of a wave is the depth of the water - shallower water slows the wave. Shimgray | talk | 22:25, 10 October 2005 (UTC)

My understanding is the same volume of water in shallower water causes the wave to go higher, so far out in deep water, the wave might only be 5 feet or so high, then when it reaches the continental shelf it can go to 100 feet high. AlMac|^(talk) 03:47, 11 October 2005 (UTC)

Frogs

Are African Clawed frogs labyrinth breathers? PLEASE HELP ME!

I've got no idea, personally, but have you looked at African clawed frog...? -- SCZenz 23:09, 10 October 2005 (UTC)

• I thought only fish were labyrinth breathers. --jpgordon∇∆∇∆ 02:35, 11 October 2005 (UTC)

Ubuntu vs Suse

I have been using Mac PCs since I was about four and Windows 9x since I was six. (I'm fourteen now.) I am now a Windows XP user. I consider myself to be fairly proficient with using computers and not screwing anything up, and recently I have been looking into installing a Linux distro on my older computer. I'm leaning heavily towards Ubuntu because I know for sure it has a GUI (which, sorry, is a requirement for a newb like me), is customizable and is, so I hear, easy for newbies. However one of my friends insists that I should get Suse, because "Ubuntu is for people who know what they're doing" and "Suse comes with more programs." I find this to be rather dubious, but I would like a final answer on this one -- should I get Ubuntu or Suse, or some other distro entirely? Thanks. ♥purplefeltangel ^(talk) ♥ ^(contribs) 21:18, 10 October 2005 (UTC)

Practically every Linux distribution designed for desktop use has a GUI, so there's no worry there. Similarly, programs tend to be available for any, since all a distribution really is in the end is a bundling-up of stuff. Nothing there to prevent someone from adding in more stuff later! Both SuSE and Ubuntu come with a great deal of stuff; since Ubuntu can use Debian packages out of the box, I think it wins in total amount of prepackaged software available. (SuSE uses RPM, like Red Hat, but they're not necessarily Red Hat compatible, while Ubuntu is explicitly Debian-compatible.) To be honest, a complete beginner won't probably notice the per-distribution differences because they are tiny compared to the differences between Linux and Windows. Both SuSE and Ubuntu offer "live CDs"; that you can boot and run without having to install anything permanently; you might try grabbing both and seeing if one or the other seems to appeal to you more. — File:Ontario trillium sig.pngmendel ☎ 23:21, 10 October 2005 (UTC)

Thank you! ♥purplefeltangel ^(talk) ♥ ^(contribs) 00:12, 11 October 2005 (UTC)

Extra question: On the Ubuntu website, where can you get LiveCDs? ♥purplefeltangel ^(talk) ♥ ^(contribs) 00:25, 11 October 2005 (UTC)

Just follow the download link, then select the release and country. For example, the page for US downloads of the Breezy Badger release candidate [12] is neatly divided into sections for install CD, live CD and combo DVD. The file you will download has a name in the form ubuntu-<version>-live-<architecture>.iso, for example ubuntu-5.10-rc-live-i386.iso.-gadfium 03:04, 11 October 2005 (UTC)

You can also have CDs posted to you for free [13]. I think everyone's waiting for the next version, due out this month. Ojw 11:46, 11 October 2005 (UTC)

I upgraded from SuSE 9 to SuSE 10 this weekend and I must say that I'm very pleased with it. SuSE 10 support all my exotic hadware such as wireless LAN, bluetooth and touchpad. However, I sometimes have problems installing software through RPM packages since they are usually build for Red Hat/Fedore, this might be better under Ubuntu since it is compatible with Debian. --R.Koot 16:02, 11 October 2005 (UTC)

New version of Ubutntu was released today. Ojw 18:53, 13 October 2005 (UTC)

A Sunny Question

Is there a link between the amount of matter leaving the sun and the strength of the sun's gravitional field? Like if hot air rises cold air rushes in to fill the space left behind? --Eye 21:50, 10 October 2005 (UTC)

I'll take a crack on answering this, although my knowledge of physics in the real world is somewhat limited, as noted in an above question :P. No, they are not (directly) related. The strength of the suns gravitational field is related to the sun's mass, nothing else. When you say matter leaving the sun, I am not quite certain what you mean. What leaves the sun is not matter, but light, and light is not matter (there might be particles leaving the sun in some sort of process that I am unaware of, but not enough to influence the mass of the sun in any way that matters). You mention cold and hot air, the thing is that outside the sun there is a near-perfect vacuum, so no convection occurs. gkhan 22:12, 10 October 2005 (UTC)

The solar wind is matter which leaves the Sun, but not because of convection. See the article for details. Matter also leaves the Sun by conversion into energy during nuclear fusion of hydrogen into helium. StuRat 23:05, 10 October 2005 (UTC)

Proper care after hip fracture.

I just noticed this question comes from the same address as the next, on anticoagulation, so they are probably related. One of the big risks after a hip fracture comes from prolonged immobilization - this is one reason for anticoagulation. You might want to look at the links from our hip fracture article. The answer to your question depends on the type of fracture, whether surgery has been performed or is contemplated, and to some extent on the health and age of the person with the fracture. Surgery and rehabilitation are common treatments for hip fracture. - Nunh-huh 02:55, 11 October 2005 (UTC)

How does coumdin work to thin the blood?

In short: "thinning the blood" means making it less likely to clot (it doesn't change the blood's viscosity). Coumadin, also called warfarin, does this by reducing the amount of clotting factors in the blood, by reducing the amount of certain clotting factors produced by the liver (namely, the vitamin-K dependent factors). Because it takes a few days for this reduction of clotting factor production to show up (when coumadin is taken in therapeutic doses), coumadin isn't useful in situations where blood must be "thinned" quickly: often heparin is started for short term anticoagulation and continued until coumadin's effects have been established. Our articles should tell you more, or you can ask any unanswered questions here if you like. You might also want to take a look at anticoagulant, and at antiplatelet drugs (which work to prevent clot formation, and are not blood thinners, which work by anticoagulation). - Nunh-huh 02:49, 11 October 2005 (UTC)

Are there any open source Internet Explorer shells?

I am looking for a working GPL'd IE shell, as some of its code may be useful for this Firefox plugin/extension. (current extension version is here) (also posted in Talk:Internet Explorer shell) --pile0nades^{talk | contribs} 03:24, 11 October 2005 (UTC)

I may be mistaken, but I believe all that's needed for the most basic shell is loading shdocvw.dll. It contains everything you need to make a WebBrowser control, and includes all the basic functions you'll need. --Pidgeot (t) (c) (e) 19:05, 13 October 2005 (UTC)

aiming at the bowl

Why is it hard to aim one's urine when one has a erection or semi erection? Even when one's penis is aimed at the right spot of the toilet bowl, the flow of urine doesn't hit where it should. What is causing this interference?

Warning, you may have damaged an important part of your anatomy through ignorance, and better check with a Medical Doctor for health guidance. There is a valve in there some place to control whether your penis delivers urine, or sperm. You do not want to be delivering urine to your future wife do you? You want to deliver sperm. The valve controls which is delivered, but you may have a damaged valve. (I not know the technical anatomy terminology.) AlMac|^(talk) 03:53, 11 October 2005 (UTC)

Yeowch! Be careful. There is a valve that separates to allow semen through and one that allows the urine to flow through. If you have an erection, the valve is shifted for the semen, leaving the urine valve closed for the moment. DO NOT any point try to direct your penis downward because that will NOT stop the erection and change the valve. The valve only changes when it is flaccid and it does this naturally. If you move your penis beyond a certain angle downward, or in any direction for that matter, you risk causing a penile fracture. --Screwball23 15 October 2005 8:11PM

• I'm not sure the question is relevant to your answer. Nothing's wrong with his valve (or whatever it is); he just wonders why it's hard to pee with a PHO (sometimes known as a Morning Glory). This is original research, but it seems to me that the average male penis changes in several ways when erect; I imagine the engorged portions of the penis are shaping the urethra and adjacent domains in a somewhat different way than the usual. --jpgordon∇∆∇∆ 04:48, 11 October 2005 (UTC)
  • I have some news, for you, Mister! Your aim is not so hot when you're flaccid! - Your Mom.
    • (rimshot) --jpgordon∇∆∇∆ 06:08, 11 October 2005 (UTC)
      • Thanks for the concern Almac, but I do not have a damaged valve. And Mum, I always wipe the seat when I miss. Thanks JPgordon, you seem to make sense, but what does PHO stand for?
        • Piss Hard On. I guess there isn't much need for an article on it (though if someone wanted to do an article on nocturnal erections, it could be vaguely interesting.) And Mom is sure mean. --jpgordon∇∆∇∆ 17:29, 11 October 2005 (UTC)
          • The semi-erection one could cope with, but a full? The only way I'd hit the target under such circumstances would be if the toilet were installed in the ceiling. Unless it were out of doors, in which case I would quite like the challenge of arcing it over a hedge into the given target area. Provided it were a windless day, of course. --bodnotbod 01:27, 13 October 2005 (UTC)

Sewerage into Power

I understand that researchers at Pennsylvania State University have found a way to use bacteria to generate power with sewerage. This is referenced here. As a student living on limited means in Canberra, Australia, how would I get the details of the research?

Try your local library- most public libaries in big Australian cities have subscriptions to New Sceintist.--nixie 05:15, 11 October 2005 (UTC)

God, I love how the concept of "library" outside this city I live is so utopically true. I need to leave this place, knowledge awaits. ☢ Kieff | Talk 05:24, 11 October 2005 (UTC)

• As a Canberran myself, the ACT Public Library Service would almost certainly have New Scientist and the National Library of Australia certainly would. Further, if you go to the ACT Public Library Service website with a valid library card you can use a wide variety of online services see [14]. These include Academic Search Premier database containing access to 4,650 publications including more than 3,600 peer reviewed publications and the Marshall Cavendish Science Reference Centre. Finally, if you went to either a public library or especially the National Library, a public librarian should be able to find what you want. Capitalistroadster 05:39, 11 October 2005 (UTC)

See what I mean? Damn, I'd be lucky if my library had today's local newspaper ☢ Kieff | Talk 06:09, 11 October 2005 (UTC)

Even small towns have book stores and if they not carry the magazine or whatever that interests you, they will be happy to order for you. AlMac|^(talk) 06:34, 11 October 2005 (UTC)

Yeah, we have book stores alright. But that's not how it works, not in Brazil or at least not this city. I asked a few places to get me these books ("My Inventions" by Nikola Tesla and the complete works of Edgar Allan Poe in the original english), that are published in São Paulo, but they said they couldn't do it, that I'd have to order from another city, even state. ☢ Kieff | Talk 07:42, 11 October 2005 (UTC)

Sorry, you misunderstand me. I have the particular New Scientist Magazine, but the article (like most in New Scientist) merely gives the general idea of the research. I have searched the NLA, the basic ACTLS, and have not found it. What journals would carry the detailed information?

School or university student?--Commander Keane 13:14, 11 October 2005 (UTC)

Here's the guy's webpage, and here's some links to his publications. --Robert Merkel 13:32, 11 October 2005 (UTC)

Thanks, that is very useful.

User:Kieff may wish to post a separate question here asking where there are places to order books, like amazon.com, that are happy to sell books and magazines to people in countries and cities in a relative dark ages of publishing distribution literacy. AlMac|^(talk) 20:50, 11 October 2005 (UTC)

Bah! I'd be buying online if I could afford that. For example, the aforementioned Poe book would cost 80 reais from amazon. That's raping my pocket. ☢ Kieff | Talk 12:57, 12 October 2005 (UTC)

Visibility of stars on Moon landing

Hello.Why are no stars visable on pictures or film of the moon landings.

• The Apollo moon landing hoax accusations article provides an explanation namely "There are also no stars seen in Space Shuttle, Mir, International Space Station and Earth observation photos. Cameras used for imaging these things are set for quick shutter speeds in order to prevent overexposing the film for the brightly lit daylight scenes. The dim light of the stars simply does not have a chance to expose the film. (This effect can be demonstrated on earth by taking a picture of the night sky with exposure settings for a bright sunny day. Science fiction movies and television shows do confuse this issue by depicting stars as visible in space under all lighting conditions.)" Capitalistroadster 07:27, 11 October 2005 (UTC)
  • ...which is actually a silly way of phrasing it. Of course sci fi films show stars in space, just as they ought to: stars are visible in space by th human eye. The movie experience is supposed to replicate you being there, and so replicate the vision of the human eye, not the limitations of film. That aside, Capitalistroadster is right — you don't see the stars because they're taking their exposure readings off that great big white thing. If they took a picture on the moon in which you could see the stars, the moon itself would be horribly over-exposed. — Asbestos | Talk (RFC) 16:25, 11 October 2005 (UTC)

Eyes have similar limitations, that's why we don't see stars during the day, or in brightly lit cities at night, they are drowned out by the light nearby. This is because we reduce the amount of light let into our eyes, which means the dim light from stars doesn't enter the eye in sufficient quantities to be visible. StuRat 23:11, 11 October 2005 (UTC)

information technology

what are the benefits and opportunities of information technology?

Is this, by any chance, a homework question?

Benefits of IT... like an awesome site where you have the opportunity to get smart people to help you with answers to tough questions... but not homework--Jmeden2000 14:22, 11 October 2005 (UTC)

Turn it around. What would modern business be like if there were no computers, because they had not been invented yet.

• A heck of a lot more people would have jobs that had not been automated out of business.
• Prices would be extremely high because we not have all the innovations from the computer revolution.
• Life would be much more miserable for poor people and the downtrodden around the world.
• See if you can find books about what life was like for ordinary people and for corporations like 50-75 years ago and ask how much of that was different because they did not have what we take for granted.

AlMac|^(talk) 02:05, 12 October 2005 (UTC)

citrusjuices

What is the content in apple, lemon and orange juice?

^^^^Monica

An apple isn't a citrus but in general, all fruit juices will have mostly water, a fair amount of sugar (probably mostly fructose), some flavor compounds, some flavonoids, and some vitamins usually including vitamin C. Citrus juices as the citrus article says will have a fair amount of citric acid. Our flavor article has a tiny bit of info. Ávila 15:48, 11 October 2005 (UTC)

Coin rolling

I have always wondered why is it almost impossible to balance a stationary coin on its edge, whereas if you throw it, it almost seems to want to roll it on its edge? Similarly it's virtually impossible to balance on a stationary bicycle... Shantavira 15:25, 11 October 2005 (UTC)

Have a look at gyroscope; the principles are the same. Briefly, it's all about conservation of the angular momentum of the rotating coin or bicycle wheel, but I don't want to go into more explanation than that here. TenOfAllTrades(talk) 15:31, 11 October 2005 (UTC)

Although it is easier to keep a moving coin on its smaller surface at a higher velocity, as TenOfAllTrades explained, simpler reasons are also at work. The coin is most likely more heavy on one side and has uneven friction on both the table, its surface, and probably, a minute off-level relationship with the ground and gravitational forces.

Of course, those small forces are very little compared to the conservation of angular momentum. A unicyclist will much more easily maintain balance with constant movement than a bicycle rider at a slower speed, albeit with a larger surface area.--Screwball23 15 October 2005 8:23PM

Code Coverage Standards

What are the industry standards in percentage for Code Coverage a software? &&&Surya

This is about Software testing? Ojw 20:14, 11 October 2005 (UTC)

Learning VB.Net

How easy would it be to learn Visual Basic .NET from a knowledge of Visual Basic and Java? — Asbestos | Talk (RFC) 16:03, 11 October 2005 (UTC)

I'd say that should be a good history for learning VB.NET. Syntactically, VB.NET is (of course) very similar to Visual Basic, but it uses a large built-in class library (the .NET framework), which is in some ways analogous to the Java standard libraries. VB.NET is also truly object-oriented in the same sense as Java, which is not really true of Visual Basic. Your VB and Java experience should allow you to pick up the basics of VB.NET quite easily. It will take some time, however, to gain familiarity with the ins and outs of the library, but it's pretty easy to find what you need in MSDN. —Caesura^(t) 18:24, 11 October 2005 (UTC)

Technology abuse

What types of tech abuse are there? If you can answer that would be great, I can't find any thing on Wikipedia. : ( --DB Master 16:41, 11 October 2005 (UTC)

Nuclear bombs? (Or any type of bomb for that matter.) Pretty much any technology can be abused. The question is pretty vague. DirkvdM 18:07, 11 October 2005 (UTC)

most any weapon can be abused, such as hand guns and other small arms. We can argue whether war qualifies as abuse. AlMac|^(talk) 20:55, 11 October 2005 (UTC)

We could? DirkvdM 05:03, 12 October 2005 (UTC)

electrodes to the scrotum? Majts 20:10, 11 October 2005 (UTC)

most computer users are somewhat familiar with a panorama of spam malware phishing computer viruses identity theft the list seems endless with more stuff constantly being added, and it is all tech abuse. AlMac|^(talk) 20:54, 11 October 2005 (UTC)

• The word abuse implies there are necessarily correct ways to use technology (i.e. I can only "abuse" an e-mail program if I use it in a way for which it was not intended). Tied to the question of technology abuse would be whether or not technologies have inherent purposes, and if so, to figure out how to talk about them. Is a technology's "purpose" defined by who creates it? What is the "right" way to use a technology? Controversial technologies — of which handguns are a good example — bring out this distinction well. Is there a "right" way to use a handgun? What is it? Are there "wrong" ways? What does this mean? Are all "wrong" ways "abuse"? (i.e., what if you used a handgun as a hammer, to set a nail? That would surely be against the intended use of the "gun" by the creator of it or in the minds of most people using it, but would it count as "abuse"?) --Fastfission 21:08, 11 October 2005 (UTC)

I wanted to write that! (so why didn't I?) I suppose that's what AlMac meant, that war might not be abuse of technology as long as the technology is intended for war. DirkvdM 05:03, 12 October 2005 (UTC)

I sorta meant computer wise. I shoulda put that in the question. If you could answer with the new information that would be great : )--DB Master 17:34, 12 October 2005 (UTC)

Try this DB Master. http://en.wikipedia.org/wiki/Malware look at everything. I think thats what you want. I learned what i know from that. Hope this helps Does anyone know some of the punishments for these crims? Like making "dialers, rook kits" and such. Lordned 17:43, 12 October 2005 (UTC)

The typical punishment is a few years in jail, followed by a good paying job working for some company that thinks the way to get ahead is by hiring computer abuse felons. That's the people who get caught, most do not. I think the best punishment was the guy who got millions of dollwars from computer swindling, stashed the money with a confederate while he was in jail, then when got out found that his confederate had absconded with the millions, and he was faced with the income tax authorities expecting him to pay taxes on the ill gotten gains. AlMac|^(talk) 18:49, 15 October 2005 (UTC)

Leptin

I would like to know how to increase Leptin in the the body, through diet, or any other way, naturally. I have been trying to research leptin, and only come up with sites trying to sell me some thing. Only this site, so far has provided concrete information. I would appreciate anyones comments on this.

You can raise your leptin levels by gaining body fat. Leptin is produced by adipose tissue cells and secreted into the blood. Blood levels of leptin serve as a signal to the brain and other systems in the body indicating the amount of body fat. Fat people tend to have higher leptin levels than thin people. alteripse 17:29, 11 October 2005 (UTC)

• WHy would you want to do that. Leptin appears important in regulating several processes and levels of other chemicals. Increasing your leptin levels drastically might cause things to get off-balance. - Mgm|^(talk) 22:04, 11 October 2005 (UTC)

• • I assume you are addressing our anonymous inquirer. I wondered the same thing. I might venture a guess that what he really wants to know is whether there is a way to do it without getting fatter, but I left this answer to teach him to formulate his questions more precisely. alteripse 23:37, 11 October 2005 (UTC)

• Some medical studies suggest that smoking reduces leptin levels. If you currently smoke, you can possibly increase your leptin levels by not smoking. Template:Entrez Pubmed --JWSchmidt 00:39, 16 October 2005 (UTC)

Alien water supply

In one of my biology text books, desert rats are mentioned as being able to survive without directly taking in water, at they can recieve it though metablolism (as water is one of the products of respiration), my question is, that if this is the case, why is it always strained that when searching for life on other planets, we must first search for liquid water. If the desert rat can really obtain all its water by this means than surely life on other planets could use similar means, and their dependace would only be on hydrogen, oxygen and carbon being available. Maria Knott 18:54, 11 October 2005 (UTC)

The main focus is probably on finding planets with the right environmental conditions for liquid water, not the water itself. Cells' chemical reactions take place in an aqueous solution, so if the entire planet's temperature is above the boiling point of water they would be unable to function -- not to mention that proteins would be completely denatured. Similarly, biological chemical reactions would function extremely slowly or not at all below freezing.

If life on other planets is physically and chemically similar to life on earth, it would almost certainly not survive without liquid water. However, as you pointed out, this doesn't mean that surface water is a necessity. Also, since we don't know anything about extraterrestrial life, it may not use the same chemical mechanisms as life on Earth, in which all we can do is speculate. --David Wahler (talk) 21:04, 11 October 2005 (UTC)

There would have had to have been (?) water to start with, to let the species evolve. The only way that such water-based life could be present somewhere without there being any more 'free' water is that all the life has consumed all the water. Which, on second thought, is entirely possible. But, like David says, how can we know that ET needs water? Or is carbon based (as is often assumed). We don't even know what defines life here on Earth, let alone elsewhere. The USSR once developed a robot that was meant to detect life on other heavenly bodies. When they tested it on Earth it couldn't find any life....

In a way we cannot even speak of extraterrestrial life since our definition (if one day we find it) is tied to the Earth. Well, alright, if some'thing' steps out of a machine that just came falling from the sky and says 'Hi', we're probably dealing with life (and with at least some intelligence at that). But what are the chances that it will look or behave anything like us? Just look at the variation of life here on Earth (remember animals and plants are both Eukaryotes, which is just one of the three (or so) different lifeforms here on Earth - the others are Prokaryotes, Archaea and possibly Viruses, but we don't even know if those classify as life). Then think of all the different variations of circumstances on those Googillions of different planets out there (well, most likely, anyway).

"There's life, Jim, but not as we know it" :) DirkvdM 05:44, 12 October 2005 (UTC)

Cool, thanks for replies I can impress my biology teacher! Maria Knott 05:50, 14 October 2005 (UTC)

Average cardboard container, as in What is the color of...

I'm trying to determine––in CMYK terms, if anyone knows how the color of the average cardboard box/container, as in the context of color, is arrived at; what percentages of each pigment is used for a box to achieve its 'cardboard-ness'.

If anyone has the inside dope on this, I'd be very appreciative of it being made available to/for me and/or for others. Thank you for your time.

I think most cardboard containers do not have any pigment added, so are the color of the constituent materials, such as wood pulp and the chemicals used to process it, typically resulting in a gray or brown color. StuRat 22:55, 11 October 2005 (UTC)

I took a picture of a cardboard box and sampled a pixel which I thought "average". It has RGB values of 168, 138, 104, and a hex value of #A88A68. --Borbrav 05:53, 12 October 2005 (UTC)

Well, not all cardboard has the same colour. I did that too, and came up with 193, 146, 46. But the question was what the CMYK values are. In my case that would be 0, 24, 76, 24. For your values it's 0, 18, 38, 34. DirkvdM 06:18, 12 October 2005 (UTC)

Then again, what values yo get depends very much on the exposure. First of all, the light has to be neutral, which makes a scanner a better choice than a camera, unless you use (artificial) sunlight. That would influence the balance between the colours. But the 'common level' (or what should I call that?) depends on the amount of light. Ideally, you'd scan with a just-no-overexposed exposure and then straighten the bottom end of the histogram as well. DirkvdM 06:47, 12 October 2005 (UTC)

Srinking Sun

Is the sun getting smaller. Is it burning up?--Eye 19:38, 11 October 2005 (UTC)

Strictly speaking yes. It loses 4 million tons of mass every second. Don't worry though it still has at least 4000 million years of fuel left. See the article on sun Majts 20:07, 11 October 2005 (UTC)

And mass is energy?--Eye 20:23, 11 October 2005 (UTC)

As Albert Einstein originally theorized, mass has a potential for energy E=mc², so yes. For the original bit, though, "burning up" isn't fully correct; the sun undergoes nuclear fusion rather than combustion. — Lomn | Talk / RfC 20:32, 11 October 2005 (UTC)

As Bill Clinton once said it it depends on what you mean by is? I thought the questioner meant does mass=energy? To which the answer is no - unless you multiply it by a very big number -speed of light² Majts 20:53, 11 October 2005 (UTC)

Yes I know it's just that I can't spell nukleer fishon :-)--Eye 20:46, 11 October 2005 (UTC)

No, mass is definitely not energy. In simplest terms mass is the weight of the sun. nuclear fusionis the process that scientists describe as the sun burning. This is the process that converts the mass to energy (light & heat). It's therefore a very good thing that the sun gets a miniscule amount smaller every year or we would all be very dead due to no light or heat. Majts 20:48, 11 October 2005 (UTC)

Just to correct some of the above statements: mass and energy are two different forms of the same thing. Mass and energy are interchangable at a ratio of E = M *C^2, where E is energy, M is mass, and C is the speed of light. (So a small amount of matter produces an enormous amont of energy.) However, this matter to energy conversion only takes place in nuclear reactions (that is, reactions that modify the nucleus of an atom). The only place you can find such reactions are inside stars, inside nuclear reactors, or at ground-zero of an atomic-bomb blast. Energy-to-matter conversion is possible (I think), but off the top of my head, I cannot think of any situations where it occurs. →Raul654 21:17, 11 October 2005 (UTC)

To clarify - I did not state that mass is not a form of energy (&vice versa), I just stated that mass is not energy, which is true. For example, if the questioner asked is liquid water, ice? No, ice and liquid water are forms of the same thing but they are in a different state. Thanks for making it clear though. Majts 03:36, 12 October 2005 (UTC)

Energy-to-matter conversion happens in electromagnetic cascades, such as when a cosmic ray hits the upper atmosphere. Two electrons are pair produced from a photon that interacts with a bit of atmosphere. But yes, it's quite rare, because entropy always increases.

And yes, mass is a form of energy from the modern physicist's point of view. -- SCZenz 22:38, 11 October 2005 (UTC)

I assume you meant to say an electron and a positron being formed from the cosmic ray. --Borbrav 23:05, 11 October 2005 (UTC)

I did, yes; although "electron" is often used to refer to both negative electrons and positrons, it's probably confusing if I do that here, isn't it? -- SCZenz 23:17, 11 October 2005 (UTC)

Actually, while the Sun currently is getting a tiny, tiny bit smaller every year, it will eventually balloon up into a red giant, as a natural part of its life cycle. At that stage, it will be big enough to actually swallow Mercury, Venus, and Earth. So don't feel sorry for our poor little star, and don't forget your sunblock. ;) --Ashenai (talk) 23:18, 11 October 2005 (UTC)

Quite right, the question was not if the Sun is losing mass, but if it is getting smaller. The expansion to a red giant won't take place for another 5 billion years or so. But right now the Sun is fairly stable I believe. But I haven't a clue if it's getting smaller or bigger. I suppose that depends on what you define as the boundaries. For the Earth it's fairly simple if you leave out the atmosphere. And even then it's fairly well defined. But in the case of the Sun I can imagine that the play you have in determining the boundary is much bigger than the change in size, which would mean that in as far as we can define it's size it remains the same. Then again, I don't know, really :) . DirkvdM 06:31, 12 October 2005 (UTC)

This question prompted me to write a new article for Celeritas - I couln't believe there wasn't one already Majts 00:08, 12 October 2005 (UTC)

Let me do this question again...Is the amount of the sun getting less as a result of what it's doing? :-) --Eye 19:37, 12 October 2005 (UTC)

Yes, if you mean is it losing mass. "Getting less" could also mean the volume is reducing, and there are other factors that effect that, like the temperature, so it isn't necessarily losing volume as it loses mass. StuRat 23:46, 12 October 2005 (UTC)

Estrogen and Adrenalin

What are the effects of taking or producing high levels of estrogen? What are the effects of taking or producing high levels and low levels of adrenalin?

As for the estrogen, you may want to start your research at Sex reassignment surgery and Hormone replacement therapy (trans) and go from there. Dismas|^(talk) 21:38, 11 October 2005 (UTC)

Dismas, 99.99% of people producing or taking "high levels" of estrogen around the world are females, not sex-changing males. Effects of estrogen depend on age, sex, and hormonal status of the person, how high the levels are, the duration of high levels, whether risk factors might be present that would amplify the effect, and whether a progestin is taken also. If you want something more specific, you will have to give us more to work with.

Effects of excess adrenaline depend primarily on how high, for how long, and whether the person has risk factors that would amplify effects. The most common effect of acute excess would be heart pounding, anxiety, tremor, pallor, sweating. Chronic excess occurs with pheochromocytoma and can include episodes of the acute symptoms, plus hypertension and eventually damage to heart muscle.

Effects of low adrenaline depend on whether deficiency occurs gradually or abruptly, and whether there are additional hormone deficiencies. In a healthy person, gradual loss of adrenal medullary function produces little in the way of symptoms, but for some people it can produce orthostatic hypotension in certain circumstances, or diabetic hypoglycemia in someone who takes insulin.

So what is your specific concern? (and don't tell me Dismas guessed it, or he gets to give you a more detailed answer). alteripse 23:29, 11 October 2005 (UTC)

I'm aware that the number of people taking it for sex-changes is small but the article on estrogen doesn't mention what would happen with "high levels". Although I hadn't read the articles I referenced, it would seem plausible that information about what the OP was looking for might be in the articles. Dismas|^(talk) 03:09, 12 October 2005 (UTC)

No offense intended. As you saw from my finish, I agree that you might have the opportunity to say "I told you so." However I could think of a whole lot of other contexts as well. And I had no idea what "high" was intended to mean. High relative to what? If the inquirer is sincerely interested he/she can give us more details and I will try to come up with a more precise answer. alteripse 03:23, 12 October 2005 (UTC)

No offense taken or intended on my part either. And I agree, "high" is a relative term. I took it to mean "having effects above and beyond what would be demonstrated by someone with a "normal" amount of estrogen/adrenaline in their system for their gender". It seems to smell of homework to me though. It makes me think of some high school health class concentrating on hormones in the body since I can't think off hand of how else the two would be linked. Dismas|^(talk) 04:29, 12 October 2005 (UTC)

This was not a high school question. Basically not even a board certified endocrinologist could fill in every space in the matrix I outlined without looking a few things up. Few medical students or non-endocrinologist physicians could fill half of the possibilities even given a couple of hours and a standard endocrine textbook. Give it a try and you will see what I mean.

I assume our inquirer has a specific situation in mind involving either self or a close acquaintance and with the details I might be able to better answer. alteripse 04:38, 12 October 2005 (UTC)

Invisible Spark

I am told that when we “see” a spark of electricity (or lightening) what we are seeing is electricity burning up air and/or water molecules. Is it possible to have a discharge of electricity that is invisible or does electricity always have to have a medium to travel through?--Eye 20:20, 11 October 2005 (UTC)

By "electricity", I assume you mean electrical current. Current is any flow of electrically charged particles. For example, current flowing through wires is the movement of electrons from one metal atom to the next. In the case of lightning bolts and sparks, the air's electrical resistance generates so much heat that the air molecules momentarily glow white-hot, just like in a light bulb. But a current can also flow through a cold conductor, or even a vacuum (see cathode rays), and in those cases you wouldn't see anything. --David Wahler (talk) 21:11, 11 October 2005 (UTC)

A fluorescent lamp also uses an electric current to make a gas light up, but it doesn't burn it up. DirkvdM 07:06, 12 October 2005 (UTC)

I think it's unlikely that the spark is "burning up" air or water vapour; arguably the production of ozone from oxygen could be counted as "burning oxygen" but I don't know that ozone production causes visible light. I think what you're seeing is the ionization and re-combination of oxygen and nitrogen. (And since sparks are common in dry air, I don't think water vapour is a big contributor.) Your last question is actually two unrelated questions: (a) Many discharges produce a wide range of electromagnetic wavelengths, right up into the radio spectrum, so perhaps there are contrived environments in which discharges produce no visible light; I don't really know. (b) Normally when we speak of an electrical flow we're talking about the exchange of electrons from one atom to its neighbour, whether smoothly in a conductor or chaotically in a spark; that requires a medium by definition. But an ion beam in a vacuum is also very much a flow of electricity. And induction can certainly happen through a vacuum, without even electrons passing; some would argue that it's not a "flow of elecricity" but it can certainly be part of an alternating current circuit. Sharkford 14:11, 12 October 2005 (UTC)

Losing its Shine

If the sun is losing mass, but not in the form of light because light is a massless partical, do solar eruptions and the solar wind account for all the mass being lost from the sun? --Eye 21:07, 11 October 2005 (UTC)

Also, some mass is changed into energy due to fusion of hydrogen into helium and other nuclear fusion reactions, according to Einstein's famous equation $E=mc^{2}$. StuRat 22:33, 11 October 2005 (UTC)

"Loose" is the opposite of "tight." "Lose" is the opposite of "win" (or "gain"). Now you know, and knowing is half the battle -- please tell your friends so that we can stop this abhorrent typo from perpetuating! Garrett Albright 20:05, 12 October 2005 (UTC)

vulcinism and evolution

Bold textItalic textI am very interested in volunology, and I watched both"supervolcanos"and "the Day the Earth Almost Died"(the {ermian extintion). So my quwstion is, which volcanic event-Basalt Floods(the Siberian Traps), or a supervolcanic eruption(like toba) has more of an effect on glbal climate and subsequent evolution?

The eruption that puts more ash into the atmosphere poses a greater global selection pressure on existing species. alteripse 23:34, 11 October 2005 (UTC)

Orange juice vs. apple juice

Why is it that, in a grocery store or market, orange juice is usually sold out of a cooler but apple juice (also, cranberry, grape, etc.) is generally kept on shelves? Would the orange juice spoil faster if it were on a shelf? Dismas|^(talk) 21:34, 11 October 2005 (UTC)

What country are you in? Here in NZ, all juice is equal in the eyes of the retailers, and live peacefully together on shelves. Perhaps most people just want to drink OJ now, and so it's kept cool to encourage this?--inks^T 21:39, 11 October 2005 (UTC)

Does NZ import its juice? That is probably the reason. We have dozens of varieties of OJ, with and without pulp, added calcium, added vitamins, preservatives, etc. Some are reconstituted from concentrate, many brag that they are not. I suspect the absence of preservatives and whether the product is reconstituted are the major things that determine need for refrigeration, not enticement to drink. alteripse 23:07, 11 October 2005 (UTC)

The U.S. Dismas|^(talk) 23:22, 11 October 2005 (UTC)

Store apple juice is nearly all pasteurized and has preservatives added that allow it to be kept at room temperature. You can do that with orange juice too but there is a much bigger taste difference that the folks in NZ are apparently missing. alteripse 23:32, 11 October 2005 (UTC)

Can't say I pay much attention to store layout....there is some "premium" juice that costs five times more than petrol that only lives in the coolers, and it does claim to be "preservative free", "not from concentrate" and "no added sugar"....so I'd venture that you're right with regards to preservatives and freshness :) --inks^T 23:58, 11 October 2005 (UTC)

Yeah. I'm not a picky man, but I can easily tell the difference between the stuff sold refrigerated and the stuff sold "on the shelf". (Incidentally, this was something I loved about the US - pints of good, fresh orange juice, for virtually nothing!). The real end of the scale is the stuff a housemate used to drink gallons of - the cheapest supermarket orange juice, would keep for about six months in the carton, but... ugh. Tasted like I was having heartburn. Shimgray | talk | 00:58, 12 October 2005 (UTC)

This was something I always disliked about Germany. The available juice was inferior to the refridgerated stuff in the states (the only more expensive alternative I saw was fresh squeezed offered by some restaurants), and in most homes I visited, orange juice was mixed with carbonated water. That of course didn't stop me from buying and drinking orange juice in what my neighbors clearly thought was inordinate quantities. — Laura Scudder | Talk 19:54, 12 October 2005 (UTC)

New Zealand imports most of it's orange juice- so the affordable stuff is the nasty reconstituted juice that can be kept at room temperature while unopened - fresh juice is available in most supermarkets but the price is premium. Juice from all fruits can be stored at room temperature if enough sugar, water and preservatives are added.--nixie 02:18, 12 October 2005 (UTC)

There are several ways to keep your OJ from spoiling:

• Room temperature:
  • Irradiate it: I guess people don't like it but I can live with it.
  • Boil it: These are the juices on the shelves.
  • Dry it and make it into a powder form: No. This is not for me.
• Rrefrigerator:
  • Rrefrigerate it and drink it in a matter of days: Currently the best choice in the U.S. and many other countries. (Freshly squeezed or reconstituted)
  • Add more sugar: Acceptible to some. But many people don't want their OJ sweetened.
  • Increase its acidity: Good for OJ. No good for apple juice.
• Even colder:
  • Freeze it: Add less water to the OJ concentrate. I don't know if these paper cans are available outside the U.S.

If you add much sugar or acid and boil it, any OJ can be stored on a shelf. I just don't think anyone would like to drink such thing. Pulp is also an added ingridient. To a juice factory, they can always blend in required amount of pulp to their reconstituted juice easily.

How do you like frozen OJ? These 400% juices (1 part OJ + 3 parts of water) are usually made from concentrates. -- Toytoy 04:19, 13 October 2005 (UTC)

Calculating number of days

Is there an article or website that makes it easy to calculate the number of days between two dates from different years? NoSeptember 22:10, 11 October 2005 (UTC)

Lots of them! Ther are also programs that will convert between calendars. Google for "date calculator". One is at time and date.com - Nunh-huh 22:36, 11 October 2005 (UTC)

Sum of a squared general term

if tn=n squared what does Sn equal??$Insertformulahere$

Anything you like. That's the whole point of using algebra to have the variables represent stuff. AlMac|^(talk) 02:09, 12 October 2005 (UTC)

I think the question was asking for the formula $\sum _{i=1}^{N}i^{2}={\frac {N(N+1)(2N+1)}{6}}$. To derive it, one would use the fact that the sum of an nth degree sequence is an (n+1) degree polynomial, and then proceed by mathematical induction or any of several other methods which are far nimbler but harder to explain. --Borbrav 05:41, 12 October 2005 (UTC)

Amount of work done

If there is a two-step process and two ways to go about doing it, would the way in which the first step has the bigger change in volume compared to the second, or would the way in which the second step has the bigger change in volume compared to the first, (but both arriving at the same final volume,) result in more work? Thanks
-- Миборовский ^U|T|C|E 00:15, 12 October 2005 (UTC)

In a system where there is no energy lost, the amount of work to get from one state to another should be equal, regardless of the path taken. Energy could be lost by things such as friction, however, then the energy loss would need to be investigated to determine which path would involve the most work. StuRat 02:19, 12 October 2005 (UTC)

OK, then let's say there are 2 cylinders with a piston, both having 10 L of air inside at 2 atm. Then the pressure is changed so that the volume becomes 20 L. Hess's law says same amount of work is done whether it's a multi-step reaction or single-step. But what if there are 2 kinds of multi-step reactions taking different pathways to reach the same result (volume)? Since work is not a state function, even though the end result is the same there should be some difference in work done?
-- Миборовский ^U|T|C|E 02:41, 12 October 2005 (UTC)

Exothermic reactions (which give off heat) will tend to lose energy as the heat energy will dissipate through the cylinder walls. Similarly endothermic reactions (which remove heat) tend to gain energy as the heat energy is "sucked out" of the environment. It's possible that a single reaction may generate or remove either more or less heat than two reactions, so experiment or chemistry would need to be used to determine which process has the greatest energy loss. Alternatively, you could just measure the amount of work in a more direct manner. StuRat 16:34, 12 October 2005 (UTC)

Who's this critter?

We were driving around the outskirts of Las Vegas when we noticed two of these deer (or whatever) in someone's yard. (There were also some rabbits, an emu, and heaven knows what else; it's not a native to the area, I wouldn't think.) Anyone have any idea what this is?

What sort of deer is this?

--jpgordon∇∆∇∆ 00:56, 12 October 2005 (UTC)

It looks very much like this one. Shantavira 11:22, 12 October 2005 (UTC)

It's either a Fallow deer or there is a Japanese version with a .....Japanese name.... which I can not remember --Eye 19:27, 12 October 2005 (UTC)

• I venture that you are 100% correct. Thank you very much! --jpgordon∇∆∇∆ 16:58, 13 October 2005 (UTC)

radio communications

I had a problem operating my fm receiver

It can be tuned to 3 stations only. Once i noticed that at a certain place in my house i could hear one station whereas elsewhere in the house I would hear a different station..

Howz this possible??? and that too only in that specific position in the house..?

Perhaps you need to get a new aerial? In response to the second part, perhaps you live in an area where two radio stations are broadcasting at a similar frequency, thus interfering with each other as you move around. --Ballchef 06:09, 12 October 2005 (UTC)

People near my place who live close to the radio transmission tower used to pick up radio (not sure if FM/AM) through their kettles. Do you live close to the transmission tower?--Commander Keane 14:33, 12 October 2005 (UTC)

The short wavelength of FM transmissions sometimes means that interference patterns can be set up that vary over the size of a house. If there is a radio reflector nearby (potentially anything sizeable and metal) you may get a pattern where the reflection cancels out the unreflected signal at one point, but a few metres away doesn't cancel it. DJ Clayworth 19:03, 12 October 2005 (UTC)

On the same frequency? If so, sounds like capture to me (see Frequency modulation). Dysprosia 22:42, 12 October 2005 (UTC)

Well thanx for all ur replies. 1. I dont think that broadcasting of two stations on same frequency is permitted. The station I am supposed to hear is the national broadcaster and uses same frequency all over India.

2.Well if reflections are cancelled out by a potential radio reflector around then how come I hear a different station at the same frequency.

Broadcasting two stations on the same frequency may be permitted if the two transmitters are far away enough so they don't interfere with each other. Dysprosia 09:56, 13 October 2005 (UTC)

...which is why the allocation of the spectrum is done by legislative fiat in most countries. →Raul654 10:11, 13 October 2005 (UTC)

spanning trees

How many different spanning trees does a complete graph have?- anon

See Spanning tree (mathematics). It depends on the size and amount of interlinking between the points of the graph in question. - 131.211.51.34 08:17, 12 October 2005 (UTC)

Here's an easy way to answer questions like this with a minimum of thought: work out the values for some small cases and then look up the resulting sequence in the On-Line Encyclopedia of Integer Sequences. In this case (assuming the nodes are distinguishable), graphs with 1,2,3,4 nodes have 1,1,3,16 spanning trees respectively. Look up the sequence 1,1,3,16 in the OEIS and you'll find OEIS:A000272, "Number of spanning trees in complete graph K_n on n labeled nodes", together with the formula. Gdr 18:12, 12 October 2005 (UTC)

Alkaline batteries

Why is it that certain devices(e.g. Door chimes and an electronic sphygmomanometer) will only work with alkaline batteries even though carbon/zinc batteries are the same voltage? Don Pierson--88.106.22.42 10:32, 12 October 2005 (UTC)

As a battery decharges it's voltage reduces as well. So while a carbon/zoinc and alkaline battery both deliver 1.5 volts when fully charged, a carbon/zinc battery that is half empty might only deliver 1.2 volts, while a alkaline battery that is half empty will could still produce 1.4 volts. This shouldn't affect purely electical devices as much as mechanical ones. --R.Koot 22:01, 12 October 2005 (UTC)

revolving of planets

Why do all heavenly bodies rotate? --210.214.228.78 12:36, 12 October 2005 (UTC)

Hi! You may not be aware of the fact that you actually asked two different questions. The question title says "revolving of planets", but you're asking why planets rotate. A planet's rotation and revolution are quite different things, and the reasons for them are also different. Planets revolve around the Sun: the Earth takes about 365 days to make one such revolution. They also rotate around their axis; the Earth rotates once every 24 hours. Which phenomenon are you interested in? --Ashenai (talk) 12:40, 12 October 2005 (UTC)

A star's rotation and it's planets' rotation and revolution are all a result of the rotation of the gas and dust cloud from which they formed. As they contract into smaller spheres, any small rotation is greatly magnified by the conservation of angular momentum, which means smaller objects must spin faster to have the same amount of "spin energy". Similarly, galaxies increase their spin rate from the original gas and dust clouds from which they formed, as they contract. The question then arises as to why these systems had any spin initially. Any system with nonuniformly distributed matter travelling at various relative velocities will inevitably lead to cases of rotation. (For example, imagine two stars going straight toward each other with a slight offset that capture each other to become a rotating binary star system.) But, this in turn leads to the question of why matter isn't evenly distributed in the universe. We don't know the answer to that, yet. StuRat 16:51, 12 October 2005 (UTC)

Actually, it sort of depends on what you call rotation. The Moon rotates around its axis once every evolution around the Earth. So it's always got one side turned to the Earth, so from our point of view you could say it doesn't rotate (causing the Moon to have a so-called 'dark side', which is a misnomer for the side we don't get t see from here). To my surprise, in a previous thread here I learned that this eventually happens to all heavenly bodies, so even the Earth will (given enough time) have it's rotation slowed down to once every 365 days (provided, of course, we stick to the length of a day and don't keep om defining it as one rotation of the Earth). So then one side of the Earth will be constantly facing the Sun. But then that may take longer than 5 billion years, when the Sun will consume the Earth. DirkvdM 18:41, 12 October 2005 (UTC)

This phenomenon is called Tidal lock. - Cobra Ky (talk, contribs) 23:00, 12 October 2005 (UTC)

Thames Barrier

How many times was the Thames Barrier raised in 2004?

According to the Environment Agency's page here it was closed on two occasions - the 22nd of February, and the 12th of November. Noodhoog 14:52, 12 October 2005 (UTC)

Most efficient photosynthetic organisms

Although I suspect there are variables that would impact relative efficiencies (temperature, sunlight, water quantity, etc.), is any organism more efficient than another at converting carbon dioxide to oxygen? For example, does an oak tree convert more oxygen than a comparably sized vat of bacteria or vice-versa? How would one go about comparing the efficiencies of photosynthetic organisms? 207.71.24.174 16:40, 12 October 2005 (UTC)

I would think a single-celled organism, such as algea, would be the most efficient, as it lacks the support structures of a tree like a trunk, branches, and roots. This means every cell in the organism is devoted to photosynthesis, rather than only a small portion in the case of trees. To test them both, you could place a leaf (still connected to the tree) in a sealed bag transparent to visible and UV light, and collect it after 24 hours. Measurments could then be made of the gas amounts. Similarly, an equal mass of algea (added to water) could be left in a sealed transparent container for the same amount of time and similar measurements made. This would compare the photosynthesis efficiency by wieght of a leaf to algea. If you wanted to compare the photosythesis efficiency of the entire tree, you would also need to estimate the portion of the mass of the tree which is leaves, and multiply by that. I suppose you could uproot a small tree, weigh it, then remove it's leaves, and weigh them, to figure this out. I'd hate to see a tree killed if not needed, though (I must have some Druid blood in me, LOL). StuRat 17:22, 12 October 2005 (UTC)

How fast do algae reproduce? Being small, I can imagine that may be something like one generation per day. For which you'd have to compensate in the above experiment. But the question was about bacteria, and I'm sure that with them this would be a factor to take into account. By the way, not all bacteria photosynthesise. There's a huge variation in bacteria that live under all sorts of conditions, and based on that alone it's extremely likely there's some bacterium somewhere that will outdo any plant in this respect (or any other respect for that matter). DirkvdM 18:57, 12 October 2005 (UTC)

If the mass of the remaining algea is different (from the original mass) when it is strained off from the water, then an average mass could be found between the starting and ending mass. This shouldn't technically be a linear average, (Mi+Mf)/2, since the mass would be expected to increase geometrically, not linearly, but for small changes a linear average would be a close enough approximation. StuRat 14:10, 14 October 2005 (UTC)

science

How does pressure affect time

It doesn't. Time could affect pressure, however, as in the pressure inside a room with an explosive which is detonated. The pressure would definitely change with time in such a room. StuRat 17:35, 12 October 2005 (UTC)

Actually, time and pressure are completely independent. In the explosive example, pressure varies with time (it would be equally valid to say that time varies with pressure) but neither affects the other. — Lomn | Talk / RfC 18:01, 12 October 2005 (UTC)

I suppose we are looking at the word "affect" differently, I am taking it to mean "correlates with changes in" and you are taking it to mean "causes changes in...". I suppose a correlation can be taken in either direction, but it would be far more usual to say pressure is a function on time, P(t), than to say time is function of pressure, T(p). StuRat 20:29, 12 October 2005 (UTC)

Compressing a fluid would change its stress-energy tensor, which in turn would change the Einstein tensor, which describes the curvature of spacetime. So yes, pressure can affect time. Not by much, of course, for pressures usually encountered. --Trovatore 02:16, 13 October 2005 (UTC)

How about in a Black hole? Would it be wrong to say that pressure affects time in these circumstances? Majts 18:43, 12 October 2005 (UTC)

Acceleration changes time/space in a black hole (or elsewhere, for that matter), not pressure. DirkvdM 19:03, 12 October 2005 (UTC)

Vide supra. --Trovatore 02:16, 13 October 2005 (UTC)

I agree, life is absolutely super! :) DirkvdM 08:05, 13 October 2005 (UTC)

• Pressure can have some small effects on a half life, though. --Bob Mellish 19:08, 12 October 2005 (UTC)

• Geesh, I didn't know that. I'll go have a look (always somthin' to learn around here). Thanks, --hydnjo talk 01:09, 13 October 2005 (UTC)

how much does it pay to work as a... and how long do you have to go to college for?

I was wondering how much on average it pays to work as a volcanologist? Also how long approximately do you have to go to school to get a degree in volcanology and can you go to a community college or do you have to go to a more extensive college? Thank you

-April S.

I don't think they do it for the money. --Eye 21:22, 12 October 2005 (UTC)

If you want to work as a research scientist in *any* field, you will need to do a four-year degree, and probably a graduate degree after that (so, all up, 7 or 8 years of post-secondary education). If you can possibly afford it, at least the four-year degree is a great thing to do anyway; college broadens the mind in so many ways other than just job-related stuff. Vulcanologists are employed by either the universities or the government, so you will earn a nice living but nowhere near what, say, a doctor or stockbroker would.

Ah, but with a minor 7 year investment, you could have your very own PHD in the field of vulcanology, which would make you what? A doctor of Vulcans, sorry, couldn't help myself--Armen Schrikken 01:29, 13 October 2005 (UTC)

However, by compensation, you get all the benefits of working as a research scientist (working with interesting, smart people, solving challenging problems that nobody has before, a fair bit of travel paid for by your job), plus a few more (your travel is often to wild, beautiful place and it's easier to impress members of the opposite sex with your job than a lot of other scientific jobs ;-) ). --Robert Merkel 21:50, 12 October 2005 (UTC)

Alas those places are not just a bit wild. What percentage of vulcanologists die of natural causes? :) DirkvdM 08:04, 13 October 2005 (UTC)

Well, a volcano is natural, sort of... Shimgray | talk | 12:23, 13 October 2005 (UTC)

I do not think that the major part of vulcanologists spends a lot of time near a vulcano crater (exacltly as an astophysic do not spends most of his/her time with his/her eyes looking at a telescope ... not to cite that he/she does not spend any time on the surface of another system star :-) ). About the wage I have seen some time ago a site with the average wage of several researcher job, but I do not remeber the site at the moment. AnyFile 16:33, 15 October 2005 (UTC)

intramedullary pins

How durable are intramedullary pins, fixated in the humerus bone? Will the pin eventually break down and have to be removed? Or will it break down and cause complications to the bone?

Today's technology utilizes titanium plates and pins which will, most likely, outlast the patient. --hydnjo talk 01:01, 13 October 2005 (UTC)

Scientists

Yes, they're the finest people on Earth. ☢ Kieff | Talk 01:23, 13 October 2005 (UTC)

Matlab, DLMREAD

Yes, this is homework, but I needed help with just one line of code, if any of you are familiar with matlab. Here was the question:

%% Write a matlab function called fileToStruct that takes in a file name
%% (with extension) and returns a structure array. The file can be either a
%% .xml file or a .txt file. 
%% If the file is a .xml file, it is an excel spreadsheet containing rows
%% and columns of data. You have to copy all the data from the spreadsheet
%% into a structure array. The first row in the excel file contains the
%% fieldnames of the fields of the structures. The second row onwards
%% contains data to be contained in the different structures of the
%% structure array. The value in each cell must be saved in the field
%% specified in the first row of that column. The first row (field names) 
%% of the excel file contains only strings. The second row onwards can have
%% either strings or numbers. However, each column will contain only one
%% type of data (i.e. either numbers or strings). The attached figure
%% (ques1.jpg) helps explain what you have to do.
%% If the file is a .txt file, you have to do the exact same thing, except
%% that the data is in this text file and it is tab delimited.
%% Notes:
%% 1) The excel file contains only 1 sheet.
%% 2) You do not know how many rows and columns contain values
%% 3) The name and number of fields (first row) can be different for
%%    different input files.

The question I have is this:

I have a text file as shown below: (tab delimited)(each name starts a new row, but i'm not familiar with wikipedia formatting, so it should be a 4 column, 3 row matrix.

Sally     Type1  12.34  45  Yes
Joe       Type2  23.54  60  No
Bill      Type1  34.90  12  No

how do i use DLMREAD to input that data? anything i tries error outs if there's a string in the .txt file, and not just numbers. Thanks so much in advance!

I haven't read your question fully but I'll give you an example from my old lecture notes and maybe that will help. When is this thing due? If it's not due today then I will give you further help (since I'm busy using MATLAB ironically), or maybe someone else will.

Here it is:

%Code to break a line of text into tokens and store in a cell array

line= 'MATLAB is an excellent prgram yada yada';

ii=1

while any(line)

[token{ii}, line] = strtok(line);

ii=ii+1;

end

Please ask again if you need more help.--Commander Keane 01:52, 13 October 2005 (UTC)

Added <pre> tags to make the code readable --WhiteDragon 17:58, 13 October 2005 (UTC)

The effect of agriculture on soil

I know that plants use nutrients from the soil in order to grow. What I'm wondering is if the amount of nutrients is limited. Suppose a farmer— an ancient or medieval one, not a modern one— uses a given plot of land for growing crops. Do the nutrients in the soil get "used up" by the crops, to the point where it eventually won't be able to support new plants? If so, how long can a given chunk of land be used for growing crops? If not, then can a farmer use the same soil over and over again?

I realize that these are rather broad questions that could have complicated answers, but I don't need all of the details. I'm only using the information to create the history of a fantasy world in a novel I'm writing, so vague generalities are fine. —Saric (Talk) 01:14, 13 October 2005 (UTC)

There are really a lot of variables here, depleting the nutrients in the soil would vary with the type of soil, crop management practices - like crop rotation which can restore some nutrients to the soil, the type of crop grown for example legumes can grow in nitrogen poor soil which other crops could not grown in since they form symbioses which give the nitrogen, and weather conditions are just a few things to consdier. The level of technology would also affect how much people understand this, for example in some parts of Papua New Guniea they cut down a small section of rainforest, grow their crop there for a few years, then move on to a new spot since the land is not as productive after a while, whereas in places like the US a farmer would just apply fertilizers to maintain a level of productivity.--nixie 01:24, 13 October 2005 (UTC)

Another way that nutrients are replenished is through periodic flooding. Seasonal flooding deposits silt loaded with organic matter on floodplains adjacent to the river. (This process made the Nile Delta highly fertile farmland for thousands of years. Unfortunately, construction of the Aswan High Dam has ended the annual floods.) TenOfAllTrades(talk) 04:26, 13 October 2005 (UTC)

I agree and add that ancient farmers had a way to replenish the soil, too, with manure. It can add back many of the lost nutrients. StuRat 04:38, 13 October 2005 (UTC)

Other things affecting the ability of soil to sustain agriculture for long periods is exposure of the area to recent (in geologic terms) glaciation or volcanism. Qaz ^(talk) 05:33, 13 October 2005 (UTC)

This is a partial repetition of what has already been said, but it is mostly a matter of putting back in what you take out. Manure does that (ground > plant > cow-or-whatever > dung > ground). Which is also the way it works in nature (leaves falling on the ground get turned into fungus dung or something). But if you constantly grow the same crop you take out the specific nutrients that that plant needs, and manure isn't usually that specific (or is it ever?). It isn't usually natural to have a long-lasting monoculture (except on poor soils, ironically).

Tropical rainforests are different. Over time the plants (trees) have absorbed all the nutrients in the soil. Anything that falls on the ground is absorbed again before it can sink into the ground. Which is why rainforest trees don't have roots that grow deep (there's nothing there) but spread out with buttresses. So if you take the trees out you're left with almost dead soil. I suppose it might work if you left all the trees to rot and then dig the remains into the ground (and maybe let that stand for a while). But that would take years and people aren't usually that patient. DirkvdM 08:46, 13 October 2005 (UTC)

Gravity and water?

Hypothetically, if I were to fall off a 200 hundred story building strait down into a deep body of water, would I land ok? I mean water is all soft an flowy, but would it provide enough support to stop me before I hit the bottom? Is this more or less safe then jumping onto a trampoline?--Talk to the yam 02:35, 13 October 2005 (UTC)

No, you wouldn't fall ok because your body's kinetic energy wouldn't be dissipated slowly. In fact, you'd hit the water as if you were hitting concrete, because the surface tension wouldn't let your body sunk immediately and the impact would be disastrous because of the extreme deacceleration you'd experience (causing a g force peak). All this energy released on a very small period would rip your limbs off your body and pratically destroy all your inner organs! ☢ Kieff | Talk 03:13, 13 October 2005 (UTC)

You's hit the water very hard because of the surface tension of the water.--Shanedidona 03:15, 13 October 2005 (UTC)

A minor physics nitpick—you're not hitting the water hard because of its surface tension; you're hitting it hard because of the water's inertia and viscosity. When you come in contact with the liquid surface, your body rapidly displaces water down and sideways to make room for itself. Since your density is roughly equal to that of water, every kilogram of your body you immerse means a kilogram of water that has to get out of your way. If you fall from a significant height, when you hit you need to move a lot of water very quickly. That transfer of kinetic energy from your body to the surrounding water is fast and painful. TenOfAllTrades(talk) 04:17, 13 October 2005 (UTC)

It is fast and painful, but not as fast and painful as hitting granite or some other hard stone. I wonder if there are any statistics of parachutists with chutes failing to open over water?

I agree and would add that the density of the water is also critical. If you've ever done a belly flop into a pool, you know just how much water can hurt. Now multiply that by 100 and you have an idea how hitting water at those speeds would feel. StuRat 04:31, 13 October 2005 (UTC)

See also Diving#The_effect_of_height_on_the_dive. This claims 66 metres to be almost certainly fatal. What's that – a 22 storey building? The article doesn't dwell on the maximum speed, but terminal velocity would be reached long before 200 storeys. Unfortunately, terminal velocity may be even higher if you adopt a streamlined diving position in the hope of survival. Apparently cliff divers regularly compete at 25 metres. I suspect that with some additional accessories, like a very pointy hat and shoulder protection, higher dives could be survivable. Notinasnaid 08:09, 13 October 2005 (UTC)

Well, it of course depends on how you hit the water. If you hit it belly down a 10 m drop would already be lethal I guess. But I once heard of a guy who jumped off a burning oil platform and survived (something one isn't supposed to do when jumping of an oil pllatform :) - they can be hundreds of meters high). I don't know how he did it, but I suppose that if you fall vertically you might just break your ankles. The first meter or so won't cause too much of a water displacement, but your feet will greatly reduce your speed - maybe the guy had big feet :) . DirkvdM 08:44, 13 October 2005 (UTC)

Mythbusters ran a segment on this concept, and the general consensus was that such falls were, statistically, uniformly fatal. Of course, there's still the one-in-a-million survival without reason (just like a handful of people have apparently survived unopened parachutes). — Lomn | Talk / RfC 12:41, 13 October 2005 (UTC)

I hear that the way to survive an unopened parachute is to maximize surface area while falling to fall as slow as possible and then arrange yourself before you hit so that a few of your biggest bones break instead of a hundred smaller bones. (I seem to recall the position is curled up on your side with your head protected in your arms, which is intended to let amongst others your arms, shoulder blades and pelvis break while preserving your skull and back.) If true this would probably be the only possible way to survive a fall into water, too, but I certainly wouldn't try it. — Laura Scudder | Talk 17:38, 13 October 2005 (UTC)

This is unsourced and most likely unconfirmed, but there was a guy who fell of a bridge he was working on, and threw his hammer into the water just before he hit, thus "breaking his fall" and i think he got away with just minor injuries. I think it was true, but, you know. :) --Ballchef 13:06, 13 October 2005 (UTC)

This is the specific case from Mythbusters and it was conclusively debunked. As noted by TenOfAllTrades, surface tension is not responsible, and a hammer does not affect the viscosity of water. — Lomn | Talk / RfC 13:16, 13 October 2005 (UTC)

Ah, so that's where i saw it. thanks --Ballchef 13:30, 13 October 2005 (UTC)

The hammer does not affect the viscosity of the water, but if the hammer fell in first it might create a 'hole' in the water if the timeing were just right and then the man would fall into water that was already partly making way for him, and would have more time to slow down.

In Chester, there is a pedistrian suspension bridge notrious for breaking the spines of people who are stupid enough to dive straight off it, even though it must only be 10-15 metres above the water (well short of the 200 storey building). Some people have even died. smurrayinchester^{(User), (Talk)} 09:37, 15 October 2005 (UTC)

If the hammer were heavy enough and it would be thrown with a lot of force the reaction to this action would slow down your fall. Imagine jumping off an airplane with a big flat rock. At first you could surf through the air and then just before you reach the ground you could jump off the rock. Don't do this at home, though (if your house were big enough to fly an airplane in, that is...). Or maybe this could become the latest thrillseekers pastime. I'd hate to be responsible for that, so please don't tell anyone about this. DirkvdM 11:20, 15 October 2005 (UTC)

Prion - Alive or no?

By the definition of a prion, it almost sounds like they should be considered a living being, yet I check the definition of what constitutes an object (or anything, im not being specific) as being alive, and it doesnt meet the majority of definitions of things that make it alive. It that case, what exactly can they be called? Its like a cross between a living creature and a simple chemical reaction; i understand at the base they are similar, so which side does a prion fall on? Living or not?

• not! not even close to livuing, just a strand of catalytic protein, by that logic you should consider your prostaglandins 'alive'--Talk to the yam 02:40, 13 October 2005 (UTC)
  • As the above comment says, not even close - they are not composed of cells, they are incapable of self-replication, they do not maintain internal conditions (homeostasis), and they don't evolve. →Raul654 09:41, 13 October 2005 (UTC)
• If prions are alive then viruses are alive. ♥purplefeltangel ^(talk) ♥ ^(contribs) 02:25, 15 October 2005 (UTC)

femoral popliteal bypass surgery

Does anyone know why a person who just had femoral popliteal bypass surgery would need to elevate the leg he just had surgery on? wouldn't you want to make sure that the new bypass gets enough blood flow to the leg to ensure patency in the bypass vessel?

Thank you.

The leg elevation is suggested to avoid deep venous thrombosis, a frequent complication of many forms of therapy, by promoting venous return. That's a much higher risk than non-patency in an artery, which probably wouldn't be changed much by leg positioning. - Nunh-huh 04:22, 13 October 2005 (UTC)

Thank you, Nunh-huh. Another reason to elevate the leg is to reduce edema. now that there's a bypass, there's more blood flow to the leg, so it takes time for the leg to adjust to the new bypass vessel. Nunh-huh, i'm just wondering, do you know if there's any empirical study done about the effectiveness of keeping the leg up? or is it just one of those medical practices that's always been done?

That's actually not a different reason: the reduction in edema is equivalent to the increase in venous return. As for empirical support: It's probably a combination of habit and study - as you realize, the oldest and least technological medical habits are probably the least studied. Most new studies concentrate on newer techniques of DVT prevention. "Elastic compression stockings are useful in patients at lowest risk for thromboembolism. Intermittent pneumatic leg compression is a useful adjunct to anticoagulation and an alternative when anticoagulation is contraindicated." Am Fam Physician. 2004 Jun 15;69(12):2841-8. DVT and pulmonary embolism: Part II. Treatment and prevention. Ramzi DW, Leeper KV. md=Retrieve&db=pubmed&dopt=Abstract&list_uids=15222649&query_hl=10. You can perhaps find something about leg elevation in some of the review articles you'd find by nosing around there. - Nunh-huh 19:10, 13 October 2005 (UTC)

rearrangement of the hydrogen and oxygen atoms around the alcohol molecules

This article introduces an invention that ages cheap wines in merely seconds by a patented electrolysis process.

http://www.timesonline.co.uk/article/0,,3-1819067,00.html

Without diluting the wine, the electrolysis causes a rapid rearrangement of the hydrogen and oxygen atoms around the alcohol molecules, which would normally take place over years if the wine were ageing naturally.

What is this "rapid rearrangement" of molecules? And by the way, I cannot find any wine-related patent by the inventor Hiroshi Tanaka (田中 博) in the USPTO's patent database. Maybe I'll check Japanese patents later. -- Toytoy 03:51, 13 October 2005 (UTC)

• Laffo, ethanol doesn't have any steric centers, you can't rearrange it, that's one of the funniest things I've read all day--152.163.101.12 04:13, 13 October 2005 (UTC)

Yes, I really don't see how to rearrange the water molecules around the molecules of CH₃-CH₂-O-H. I guess Times of London goofed by trusting this patented nonsense. I just could not get first hand information by a patent search.

How does wine age? I am not a drinker. But I guess the yeast and the wooden barrels must have done something magically (good molecules added and bad ones gone). I guess you really cannot easily accelerate these taste improving chemical and physical reactions. -- Toytoy 04:30, 13 October 2005 (UTC)

I think the process (if it's not a hoax) has nothing to do with the ethanol, but rather with a great variety of other substances present in the wine. After all, wine isn't just alcohol and water, is it? You could also check this http://www.bath.ac.uk/~su3ws/wine-faq/agingwine.html out. --Borbrav 05:51, 13 October 2005 (UTC)

I suspect that the Times just got the science wrong. I can see how passing a current through wine could encourage certain chemical reactions to proceed at higher speed, producing a very rough approximation of aging. Of course, if you're not careful I can also see how this could very rapidly produce vinegar. TenOfAllTrades(talk) 13:42, 13 October 2005 (UTC)

how can I install my second computer with internet and first computer

(no content)

(moved from WP:HD) --Ballchef 05:43, 13 October 2005 (UTC)

This is a Computer networking question? Start by saying what two types of computer you have, what Operating system, and whether they have Ethernet connectors. Ojw 12:12, 13 October 2005 (UTC)

I suspect you are asking about how to install two home computers, say connected to the phone lines, so both have Internet access. It would depend on your Internet service provider, as some allow it and others do not. For those who allow it, you need to copy their software to the other computer. StuRat 15:36, 13 October 2005 (UTC)

To share internet access intended for one computer with more than one computer, you need a couple things:

1. An internet connection, obviously.
2. A local network protocol. This is almost always ethernet (over cat 5 or wireless), so make sure each computer has an ethernet card (wireless cards use 802.11a, 802.11b or 802.11g and "wired" cards are usually 10/100, though gigabit ethernet over copper is growing in popularity. Make sure that the LAN ports of all the hosts use the same protocol as the gateway. So if the hosts want wireless access, the gateway must have wireless. Otherwise all of them should have 10/100 ethernet ports.
3. Choose one interface dedicated to internet access. This means you need to either choose one of the computers to act as gateway (this computer must have two network interfaces, for example, two ethernet cards, or one ethernet card and a modem), or else you need to go out and by an internet router (this is much more popular in the US). These can be had quite cheap these days in the US. Some considerations to make before deciding:
   1. If you choose one of the computers to act as gateway, then the performance will not be as good as a dedicated router, and the connection will not work when that computer is off.
   2. If you use one of the computers as the gateway, you might have much more flexibility over the router option, depending on the operating system on the gateway, and the sophistication of the router (routers for at home use are usually not very sophisticated). You might also be able to run a server on the gateway computer, depending on your ISP's whims, which a hardware router cannot do, and computers behind a hardware router also may have problems if there is a NAT firewall (though one can get around these problems by using port forwarding or a DMZ IP address).
   3. Most (though not all) of the hardware routers for home use do not come equipped for use with modems for dial-up (because most people in the market for home networks also pony up for broadband). If you're using dialup, and your hardware router cannot hookup to a modem and doesn't have its own modem, or if you just don't have an external modem, then you have to use one of the computers as gateway.
   4. If your ISP offers only 1 IP address with its service (which almost all consumer ISPs do. For dial-up, it's impossible to offer more than 1 using the PPP protocol typical of dial-up. For broadband, most ISPs offer only 1 IP address to residential customers, though some offer extras, for more money of course) then your gateway has to run a NAT firewall. This is possible with a computer acting as gateway, or with a dedicated router.
   5. If your ISP cannot offer you a fixed IP address, as most ISPs do not, then your gateway must obtain an IP address dynamically, almost always using the DHCP protocol. All computer OSes, router software applications, and hardware routers have this capability, and almost all ISPs support it.
   6. If you're making a wireless network, decide on a wireless protocol. The newest, fastest, and widest range wireless ethernet protocol is 802.11g, but many 802.11g interfaces are backwards compatible with 802.11b only, and not with 802.11a, so if you have 802.11a hosts, you may need an 802.11a/b wireless router.
4. Once you've chosen your gateway, connect the gateway to the internet. If you're using a computer as a gateway, then you need to enable the routing, and probably also the NAT and DHCP. In Windows, this can be done by choosing "share this connection" (or something like that) after you right click the name of the connection. With a Mac, look in the sharing preference pane. Under linux, check out iptables. If you're using a hardware router, and your ISP uses dhcp, then you probably don't need to configure it at all. On the other hand, if you're doing dialup, or if your ISP doesn't use dhcp, then you need to tell your hardware router what it's doing (and hook it up to the modem if necessary).
5. Once your gateway is connected to the internet, you need to set up your local network. That means connect your second computer to the gateway (computer or router). If you're using ethernet for the local network protocol, you'll need an ethernet patch cable, unless it's wireless ethernet, in which case you won't. If you use ethernet to connect one computer to the other computer (gateway computer), then you need a crossover cat 5 ethernet patch cable, which is an ethernet cable with its wires cross. Ask for it by name. If you want more than one computer on top of your gateway, then you should buy a switch. With a switch, you do not need a crossover cable. Use a straight-through cable with the switch, this is the normal variety of ethernet cable. Many hardware routers have built-in switches. Here again, you do not need a crossover cable.
6. Once your local network is put together, you need to configure the local network hosts. This means that each computer on the LAN must know its IP address, netmask, gateway, and some DNS servers. If the gateway runs a dhcp server, then turn on dhcp in the clients, and you should be done. Else, assign the IP addresses yourself. You can pretty much choose the IP addresses to be anything you want, as long as they're all on the same network (which means that netmask AND ip address matches for each host), but you should use networks 10.x.x.x or 192,168.x.x for NAT'ed networks. The netmask is 255.0.0.0 in the first case and 255.255.255.0 in the second. The gateway IP should match the LAN IP of the gateway you chose. (Note that the gateway is configured for two networks, and so has two IPs: one from the ISP on its WAN (ethernet or dialup) interface, and one chosen by you on the local ethernet interface. The gateway IP of all hosts on the LAN should match the second IP. ) The DNS should match the DNS given to you by your ISP. Sometimes you can also give the gateway IP, as some gateways will forward DNS requests.
7. And that's it. Once you've done these steps, you should be done. It may look like a lot, but actually, in most cases, these steps are done for your automatically by the system software, so that it actually just boils down to: 1. plug WAN port of router into cable modem. 2. plug computer(s) into LAN port of router. It can be just that easy, but just in case it's not, it's nice to know all the steps, and what they mean.

Hope that helps. -Lethe | Talk 17:43, 13 October 2005 (UTC)

If you have a high-speed internet service, such as cable modem or dsl, an easier solution is to get a home router. They are self-contained units that do all this for you, so you just plug your computers into the router (they usually have a built-in ethernet switch) and the router into your cable modem or dsl. --WhiteDragon 18:06, 13 October 2005 (UTC)

Laser Printer

What are the wattage and frequency of the laser in an average laser printer?--Shanedidona 03:04, 13 October 2005 (UTC)

please ask new questions by clicking on the correct link [[15]], not by editing at the top of the page. By adding your question to the top of the list it is seen to be the oldest question, it may not be noticed, or archived before someone gets a chance to answer. --Ballchef 05:49, 13 October 2005 (UTC)

A quick Google search on "laser printer" and "wavelength" brings us to this page from a major manufacturer, which seems to list laser diodes for laser printers from 5 to 15 mW; most are at 790 nm. Another page of possible interest would be this one. Offhand I'd hypothesize that higher power is needed for faster printing, and higher wavelengh for higher resolution, but I'll let your further research confirm or refute that. Sharkford 18:38, 13 October 2005 (UTC)

Hamburger spoilage

Last night my wife took out a sealed pack of frozen hamburger patties. They are Wal-Mart deli burgers, and heat sealed in a plastic tray. She put them in warm water in the kitchen sink to thaw at around 5pm. However, I didn't cook them, due to unforseen circumstances. When I got up this morning to pack my lunch, lo and behold, there was the package still in the sink. I put them in the refrigerator at 7am. The question is now, are they safe to eat if cooked properly? The water was quite cool this morning, and the package is still sealed. I hate to waste food, but I hate food poisoning more...Brian Schlosser42 11:38, 13 October 2005 (UTC)

"Can it kill a brown dog?" - A good test is to see if a dog will eat it, and if so, will it survive? The colour of the dog is trivial, but brown dogs are funnier. (This was a segment from a TV show a few years back in australia, where the host would cook up some crazy mix of (often rotten) food, then feed it to his brown dog. If the dog ate it, he ate it). A foolproof test. --Ballchef 12:57, 13 October 2005 (UTC)

I don't have any dogs to experiment on, brown or otherwise. My pet roach, archy, is on vacation in the local landfill, but I wouldn't trust his judgement on what foods are good to eat. Brian Schlosser42 13:50, 13 October 2005 (UTC)

Judging from the length of time, I would say no, probably rotten. You can check it by look and smell, though. If it's gray or even worse, green or blue, toss it out. If it smells unpleasant, toss it out. If you decide to eat it, cook it thoroughly, as well-done burgers are less likely to make you sick. And don't let it languish in the fridge, as it will continue to spoil there, although at a slower rate. StuRat 15:18, 13 October 2005 (UTC)

With a larger chunk of meat, you would also have the option of cutting off the surface, with is likely to rot first, and only eating the interior. But, with individual patties, you wouldn't have much of anything left. StuRat 15:24, 13 October 2005 (UTC)

I would note that with ground meat products this practice isn't quite as effective—nasty stuff that was deposited on the surface of the freshly butchered meat gets distributed throughout the block of meat by the grinding process. (This is why you can safely eat a rare steak–the bacteria on the outside are killed during cooking–but you should cook hamburgers all the way through. Don't go poking that raw steak with a fork, either; you'll let the tasty juices out, and potentially transfer harmful bacteria into the sheltered center of the cut of meat.) TenOfAllTrades(talk) 16:38, 13 October 2005 (UTC)

Also, I suggest that if you do eat it, save it for healthy adults, as children, the elderly, and those with immune problems would be more susceptible to food poisoning. StuRat 15:30, 13 October 2005 (UTC)

So have you decided what to do with the meat yet? If you still haven't eaten it, well, you'd better throw it away. Personally I have eaten meat that has been sitting out for more than 24 hours, and I'm still alive! I do this regularly to thaw my stuff. Just cook everything very well. People are made to be scared of so many things these days. --216.191.200.1 16:18, 13 October 2005 (UTC)

I've spoken to my wife, and told her to throw it out. I'd rather be safe than sorry, to coin a phrase. Thanks for the advice, folks. Brian Schlosser42 16:33, 13 October 2005 (UTC)

I don't believe you coined that phrase. -Lethe | Talk 16:57, 13 October 2005 (UTC)

No, I didn't. I try to rectify using clichés by seasoning them with sarcasm. I started doing this one dark and stormy night...Brian Schlosser42 19:59, 13 October 2005 (UTC)

I'm sure you made the dogs that go thru your trash at night very happy, LOL. StuRat 02:59, 14 October 2005 (UTC)

Or dead. Unless they're brown. :) DirkvdM 11:33, 14 October 2005 (UTC)

No, sadly, they were tossed into the dumpster, so no brown dogs got to eat deadly meat. Oddly enough, I stopped after work and bought some replacement burgers to cook, and one of them slid off the griddle and onto the floor. Apparently I was not destined to enjoy cheeseburgers last night...Brian Schlosser42 19:35, 14 October 2005 (UTC)

One survival technique to test if you can eat something in the bush is to see if monkeys eat it. What they eat we can usually eat too. Failing that, the steps are 1) rub between your fingers 2) rub under your armpit 3) rub on your lips 4) chew a bit and spit it out. Wait for a few minutes after each step. If you feel any irritation after that don't eat it and don't continue to the next step. Then swallow a bit and wait for a day. If you don't get sick it should be safe to eat. Not that that doesn't apply here, though, just showing off some of my knowledge (which is basically the hedonistic reason I spend so much time here). DirkvdM 11:33, 14 October 2005 (UTC)

Your rubbing test is even siller that my brown dog bit. what does it do? --Ballchef 14:56, 14 October 2005 (UTC)

I'm guessing that the idea is to test progressively more sensitive areas of your body for the irritation that might indicate some sort of toxin or allergic reaction, right, DirkvdM? Brian Schlosser42 19:33, 14 October 2005 (UTC)

Right. Sorry, I was a bit too concise. DirkvdM 11:11, 15 October 2005 (UTC)

Are you going to rub a Wal-mart deli burger under your armpit?

I'm Dutch, and we don't have walmart here. So the answer would be no. But then I said I was just showing off and that it wasn't relevant to the question. DirkvdM 11:11, 15 October 2005 (UTC)

Mean reverting process

What time series analysis tools do you use to determine whether a series is mean reverting or not? --216.191.200.1 16:11, 13 October 2005 (UTC)

Macromedia Flash 8

Does anyone know any tutoorials on/about maromedia flash 8? I went to www.superflashbros.net and looked at there tutorials, but i am looking for something more detaileda bout makin the character models. Any ideas? Lord Ned

Calculating charge on suspended spheres

How do I calculate the charge of two spheres suspended on a length of material of a given length, which repel and once they reach equilibrium are separated by a distance r.

--DJK

Assuming that the two spheres are at rest, you can balance the forces on one of the spheres (see free body diagram) to find the electrostatic force. There are only three forces on each sphere, tension, a Coulomb force and gravity, and you know which direction each force is in (or can figure it out by drawing what you know about the setup). If you assume that each sphere has the same charge you can find the charge from the magnitude of the Coulomb force and the distance between the spheres. — Laura Scudder | Talk 17:26, 13 October 2005 (UTC)

Mg or Mcg ?

What is the difference between a 250 Mg tablet and a 250 Mcg tablet. I know that Mg is milligram, but what is Mcg?

--MCG is microgram. Given symbol u. (Not sure how to show it properly here). It has the value 10^-6 or 1/1,000,000.

Milligram is mg and microgram is μg (the Greek letter mu is the symbol for micro) --WhiteDragon 18:38, 13 October 2005 (UTC)

Milli is 1/1000. 10^-3

Therefore 1Mg is 1000 times bigger than 1mcg.

--DJK

You can get Greek letters this way: the code μ generates a μ. Capitalization of the letter depends on the capitalization of the code: γ and Γ generate γ and Γ, respectively.

A style note—capitalization matters in the metric (SI) system. A capital 'M' represents the prefix 'mega'–10⁶–while a lowercase 'm' represents 'milli': 10^-3. So technically 1 Mg is a million grams, or one metric tonne. (Usually the special abbreviation t is used for the tonne to avoid confusion.)

Engineers also sometimes use 'mmg' (a milli-milligram) instead of μg; fortunately this warped practice is disappearing. TenOfAllTrades(talk) 18:14, 13 October 2005 (UTC)

Mcg is a microgram which is a millionth of a gram. Mg is a milligram which is a thousanth of a gram.

LISP blues

It seems that LISP interpreters I've tried so far (GCL, CLISP, and CMUCL) don't include built-in predicates for easy hardware-level or system kernel-call programming; it's possible, but it requires writing code in C and then linking it into your LISP module with a not-well-documented set of steps you have to take; and then, that ceases to make your program purely LISP/CLISP, although I am open to loading dynamic libraries. But how to load dynamic libraries common to the system, such as svgalib, seems to be even less documented in these interpreter implementations, so I'm at a stalemate here. I've fallen in love with this language this past month but I'm becoming quickly frustrated with the fact that LISP is looking more and more like a souped-up, glorified shell scripting language to me than a full-blown language that can easily do what C/C++ are capable of in terms of utilizing kernel system calls for more serious applications.

Are there any LISP/CLISP interpreters out there which allow for easier hardware-level programming and has easy-to-understand and well-versed documentation about loading dynamic libraries and everything else I need to do? Considering how old this language is I thought it might be easily done by now; any language older than C should be just as capable of OpenGL, if you know what I mean. I'm also at the point where I'm open to spending money on a proprietary LISP suite with nonstandard predicates and functions (equivalents of ioctl, etc) if I have to get these features. --I am not good at running 17:43, 13 October 2005 (UTC)

I'm pretty sure that as a native code compiler CMUCL (or its cousin SBCL) is your best bet for low-level hacking. The 'Alien Objects' and 'UNIX Interface' chapters of the CMUCL user manual should be useful. Just about all hardware and kernel-level functions are available, for example the unix-ioctl function in the unix package provides access to ioctl's. While C language libraries won't quite feel like lisp libraries, linking and calling them shouldn't be too difficult unless you are doing something wrong. Of the things you are concerned about, the only real deficiency is AFAIK access to C++ libraries, where you need to write a wrapper interface using the C++ extern "C" linkage. If you have any further questions, the cmucl-help mailing list would probably be helpful. 84.239.128.9 19:47, 13 October 2005 (UTC)

growth and development

what is the difference between growth and development?

For biological organisms, growth and development are often related aspects of how they mature and adapt to their environments; growth is often described as one aspect of development. When a distinction is to be made between the two, "growth" usually means an increase in size without fundamentally changing what it is that is growing. For example, a tumor might grow to twice its original size by cell division and cell growth. In contrast, other forms of "development" usually involve fundamental changes such as differentiation and morphogenesis. "Differentiation" meaning a significant change in the properties of a cell (changing from one cell type to another) and "morphogenesis" meaning a significant change in how a group of cells interact to form a tissue or organ. --JWSchmidt 20:40, 13 October 2005 (UTC)

Interesting. However, I usually hear that query in the context of economics. Simply put, growth is a simple increase in Gross domestic product, while development is an "improvement" in a country's overall economy. Obviously, that is a very subjective idea. Objective measurements for development include GDP per capita, the Human development index, and capital inflow, but there are many perspectives on this very complex idea. See economic growth and economic development. Superm401 | Talk 00:39, 14 October 2005 (UTC)

If you read our Economic development article it discusses development and growth as basically the same thing. As I've thought of it though, improvements in infrastructure type items, like roads, health care facilities, communications, etc are examples of development that may occur in times of contraction, not economic growth. Of course those investments as they are called in economics do contribute to GDP, but if overall GDP is falling in the short run, these investements may not contribute to growth in that short run. In general it is believed infrastructure improvements will lead to or at least remove barriers to future growth. Ávila 14:45, 14 October 2005 (UTC)

If it implies that, it's misleading people. I'll take a look at it. Superm401 | Talk 22:45, 15 October 2005 (UTC)

Quantum Time

Does time flow as a smooth linear stream or does it jump forward in tiny steps, and if it jumps in tiny steps does time stand still in between steps?

Yes no maybe ask someone else um maybe yes no. (I'm highly qualified in the field, as you can see). You might find Planck time informative; it's the "smallest meaningful unit" of time, so effectively the amount it's quantized in - nothing can happen in less than the Planck time - but I'm not sure it's really meaningful to talk about time "standing still" between steps. Shimgray | talk | 22:13, 13 October 2005 (UTC)

• Take a look at our article on time for a discussion of this. This hinges upon what time is which is a very difficult philosophical and physical question to answer. I believe the answer is, "nobody's really sure and we don't have any way to test the difference between the two at this point," though I am not an expert on this in the slightest. --Fastfission 00:38, 14 October 2005 (UTC)

Yes indeed - this is a very deep question. Certain formulations of quantum mechanics do not have quantization of time. Other more exotic species of the theory do, and of course, this includes crackpot theories and the like. The quantization which occurs in nature should not be taken too literally though - it is much more sophisticated and beautiful than what is suggested by saying that there are "jumps" in these tiny physical systems...More on that if you are interested...(and please, dig through the archives of the RD - a number of interesting quantum mechanics questions have been answered related to this topic.) --HappyCamper 00:50, 14 October 2005 (UTC)

If you want to get really confused, have a look at Zeno's arrow paradox. Here's the formulation from the philosophy pages: If motion occurs in discrete intervals, then at any given moment during its flight through the air, an arrow is not moving. But since its entire flight comprises only such moments, the arrow never moves.

About Planck time. If that is the smallest amount of time that has any meaning (to us...?) then any question about time (or whatever) in between would be meaningless. DirkvdM 11:55, 14 October 2005 (UTC)

Well, if one is going to be NPOV, one should say that any measurement of less than Planck time is meaningless. The distinction is actually quite significant to, for example, 't Hooft's attempt to resurrect hidden variable theory. --Diderot 14:08, 14 October 2005 (UTC)

I just read The Fabric of the Cosmos: Space, Time, and the Texture of Reality (ISBN 0375412883) which talked about this, you might pick it up! --Quasipalm 17:27, 14 October 2005 (UTC) BTW, the simple answer is we don't know. Please find out and report back to Wikipedia!

Exellent response Wikipeople. Thanks--Eye 19:27, 14 October 2005 (UTC)

You might also find some interesting links on the time travel article.

Many years ago I read of an experiment in which an atomic clock was taken into space on the shuttle, then when came back down, compared time to the one that had been on Earth the whole time. I forget the results of the experiment. AlMac|^(talk) 18:58, 15 October 2005 (UTC)

Sundown?

What time does the sun set? this time of year?--Egegeggegeg 22:11, 13 October 2005 (UTC)

It changes day to day. Try this website for info on your location or here. Dismas|^(talk) 22:23, 13 October 2005 (UTC)

Depends entirely where you are, so I'm afraid we can't give a meaningful answer without a location. Shimgray | talk | 22:22, 13 October 2005 (UTC)

Dry Ice

What are the properties of dry ice? How do you keep it from evaporating?

See Dry ice and for the second question, keep it frozen? Dismas|^(talk) 22:25, 13 October 2005 (UTC)

To keep the dry ice from sublimating (that's what going from a solid to a gas is called, not evaporating), keep it well insulated and place it in a freezer. A styofoam box could be used to insulate it, but a thermos would be better. Be sure the lid has vent holes in it, or is left loose, so the pressure doesn't build up and cause an explosion when it does sublimate. With luck, it might last about 3 days in the freezer. StuRat 02:44, 14 October 2005 (UTC)

I assume that a loose lid will work better than holes because it works like a valve and the build-up of CO2 gas will slow down the sublimation. I'm especially interrested if the latter is true. DirkvdM 12:38, 14 October 2005 (UTC)

The loose lid wouldn't allow pressure to build up either (that's why sodapop with a loose lid doesn't go "PFFFT" when you open it). In this case, two things are important, the total area of the opening and that no one opening is large enough for a convection cell to establish itself. That will only allow the less efficient conduction through air, which is quite slow as thermal transfer methdos go. However, you could also put a pressure relief valve in instead of a hole or loose top. That would be better, but some of those can fail in the closed position, say if water in the air freezes them shut, so sounds risky to me. StuRat 13:28, 14 October 2005 (UTC)

Also note that you won't get a convection cell, where hot gases rise because they are lighter, and cool gases fall because they are heavier, setting up a circular motion, so long as the opening is in the top of the container. Having the cool gases under the hot gases will prevent this, due to gravity. However, a thermos on it's side, with the cap missing (say if it fell over in the freezer) could very well set up a convection cell. StuRat 13:34, 14 October 2005 (UTC)

Well, a styrofoam lid would be to light for a proper pressure to build up, but if you put a weight in it it would act as a valve. DirkvdM 11:04, 15 October 2005 (UTC)

video game slowdown

Sometimes when playing a video game on an Xbox, PS2, or other console the frame rate seems to slow down when there is a lot going on in the game. What causes this slowdown? Is there any way to prevent it or make it less frequent? solaro 00:33, 14 October 2005 (UTC)

Largely lack of memory, I think. If it's a console, you can't really do much about it. Superm401 | Talk 00:43, 14 October 2005 (UTC)

If there is an option to reduce the resolution of graphics, that might allow the frame rate to speed up. Also, certain games may have ways you can play them to avoid having so much on the screen at once, and that would certainly help. StuRat 03:08, 14 October 2005 (UTC)

Home console video games almost never have options to reduce the graphics settings… that's all in the world of PC games. Anyway, what causes this is just too much data being tossed at the graphical hardware in the console for it to process in real time, so it has to take a little bit more time between frames for it to finish its work. Clearly this is undesirable, so most of the time game developers work overtime to make sure this rarely or never happens in their games, but with the super-complex games of today it's difficult to predict every single situation that may occur in a game. Sorry, there's not really a way to fix it. Garrett Albright 07:46, 14 October 2005 (UTC)

One way to limit how much is on the screen at once is to zoom in (in games with that option), so much of the action is off the screen. StuRat 13:06, 14 October 2005 (UTC)

Royal Society Fellowship

I have been reading about the Royal Society, especially about John Wilkins. Can you tell me about how many fellows there were in the Society in any particular year in the very early part of the 1700's. For example, there might have been a total of deceased and living fellows of 650 in the year 1712. From David F. Grobe, 1207 Bevabeck Dr., Marion, Illinois, USA, 62959

The Royal Society have a searchable online database here although it doesn't exactly provide what you are looking for, as it only seems to be searchable via date of birth and not when they were elected. So there were 862 fellows either alive or dead in 1712 but many of those were still to be elected. They also have all of this data in 26 separate pdf files (yes, seriously!) on their web site, so you could always pull the data out of these if you have too much time on your hands and fancy some slow torture - or you could just contact the Society direct, which would be much less painful and while you're there tell them to put their data in xml format. Majts 02:11, 14 October 2005 (UTC)

meth

(moved from top of page)

Are these chemicals used in the production of meth? Someone keeps buying nasal medicine with it.

Benzalkonium Chloride, Camphor, Chlorhexidine gluconate, disodium EDTA, and tyloxapol. 208.53.200.38 01:26, 14 October 2005 (UTC)

Dear questioner,

I have no idea, but it would help you in future to read the instructions at the top of the page and click here when asking a question so that it is the newest question, not the oldest. --Ballchef 03:34, 14 October 2005 (UTC)

• Vick's Sinex, or some generic copy of it, I imagine. The camphor is sometimes used to enhance the effect of ecstasy. Look up sinex abuse on Google; there's some interesting stuff. --jpgordon∇∆∇∆ 16:39, 14 October 2005 (UTC)

Why is soapy water so slippery?

My guess is soap molecules bind weakly to both contacting surfaces and thus prevent the formation of links between two surfaces. -- Toytoy 04:02, 14 October 2005 (UTC)

Slipperiness is a general characteristic of bases. I'd guess that the excess OH^— ions attach to the exposed hydrogen atoms on the surfaces, whereas normally these sites would form hydrogen bonds between the surfaces. — Laura Scudder | Talk 04:11, 14 October 2005 (UTC)

That's a good theory because water solutions of strong bases such as NaOH can be very slippery. -- Toytoy 04:17, 14 October 2005 (UTC)

Back when I worked with NaOH on a regular basis I never felt the need to try it out, but that was mostly because of the whole burning thing with my concentrated stuff. — Laura Scudder | Talk 04:27, 14 October 2005 (UTC)

You get a soapy feeling on your fingers after having spilt sodium hydroxide solution on them because you have created a small amount of soap! The alkaline solution has hydrolysed some of the ester links in the grease on your fingers to give the sodium salts of the fatty acids, aka soap. The alkaline hydrolysis of esters is known as saponification for this reason. Physchim62 11:33, 14 October 2005 (UTC)

See above and add... The Sodium Hydroxide will also hydrolyse some of your skin as well as any grease and these molecules tend to slide over each other easily.

Soap contains the same sorts of long chain hydrocarbon molecules as do oils. I suspect that these molecules can create conditions we call "slippery" because there are only weak attractive forces acting to hold these kinds of molecules together. When soaps and other oils interact with surfaces, they "fill in the rough spots" on other materials and form lubricating molecular domains that replace otherwise high friction solid surfaces with "virtual" surfaces (hydrocarbon coatings) where the weakly interacting hydrocarbon molecules glide past eachother. --JWSchmidt 14:00, 14 October 2005 (UTC)

About pregnancy

Can swallowing cum cause pregnancy in women

• No, and it can't cause pregnancy in men either.--Pharos 06:08, 14 October 2005 (UTC)
  • Ex Africa semper aliquid novi... There's a recorded case from Johannesburg(?) in the 1980s where a woman who'd fellated her lover was discovered by her boyfriend, and in the intervening fracas stabbed; it appears the sperm was able to transit the wound before it was properly dealt with. (How she didn't get peritonitis or something I don't know). The major reason this origin was realised is because she was incapable of normal conception. (Oral conception. Impregnation via the proximal gastrointestinal tract in a patient with an aplastic distal vagina. Br J Obstet Gynaecol. 1988 Sep;95(9):933-4) Shimgray | talk | 15:33, 14 October 2005 (UTC)
• Do remember, it can cause sexually transmitted diseases if the man who's stuff you're swallowing has one, so it pays to be careful. - 131.211.51.34 07:07, 14 October 2005 (UTC)

That gives the impression that it is more risky to swallow. This isn't the case, you will have just as much chance receiving an STD if you spit. Majts 08:35, 14 October 2005 (UTC)

• However, if any cum escapes ingestion, it is still capable of causing the pregnancy you are wishing to avoid, even in very small quantities. So, be careful that any surface that has been "spoiled" does not touch anywhere near your seat of delight, and its environs -- least you "cross contaminate" to borrow a term from the world of food preparation. Qaz ^(talk) 08:19, 14 October 2005 (UTC)

I'm sure that's a myth. The seat of delight as you call it, is a hell of a long way for a sperm to travel to the overies without "direct injection". You'd have to be trying very, very hard to get your so-called cross contamination Majts 08:35, 14 October 2005 (UTC)

To be fair, I said to avoid the seat of delight (it was described thus by Realdo Colombo, one of the first to describe it for Western science) and environs. My point was that when trying to avoid a very high cost situation (allow me to employ another analogy) it is good to not just avoid hitting the target but also to stay off the firing range. Or, put another way, avoid the target and its environs. This person would take no comfort if they were to parent a child that was possible but not very probable. Qaz ^(talk) 09:08, 14 October 2005 (UTC)

And then there's the story of the woman who took a bath in a hotel room in which the previous male occupant had masturbated and consequently got pregnant (the woman, I mean :) ). If this could in principle be possible (which I doubt), then how long would the sperm survive and would any soap help in killing it? DirkvdM 12:50, 14 October 2005 (UTC)

I particularly like the quote from Realdo Colombo "the clitoris, which he called the "love or sweetness of Venus," and which he claimed to have discovered." It's just a shame he didn't leave instructions! Majts 09:37, 14 October 2005 (UTC)

• No, swallowing pretty effectively kills any risk of pregnancy. Oral sex can, however, lead to pregnancy if you use a condom. We ought to have an article on State of Louisiana v. Frisard since it's really such an odd case: A man is held liable for child support after a woman impregnates herself from sperm in a condom he used to receive a blowjob from her. But I can't find complete information about it on the web. --Diderot 10:08, 14 October 2005 (UTC)

We do have an article now State of Louisiana v. Frisard Majts 11:14, 14 October 2005 (UTC)

Something very similar happened to Boris Becker, it is called Samenraub. David Sneek 18:11, 14 October 2005 (UTC)

dogs

Do male dogs have an Adams apple?

Yes, in fact, almost every neck collar for a dog indicates that the collar should be strapped above the Adam's apple in dogs. Since dogs are mammals, they would probably exhibit similar secondary sexual features analogous to human puberty, including the development of an Adam's apple. One misconception of note is in your question; human males and females both do have Adam's apples. Males simply have ones that happen to jut outward more, making them distinguished in this feature. The pronunciation is great enough that the Adam's apple can be termed as an sex-determined or sex-inherited trait, but not one always exclusive to males.

Check Adam's apple and Oxford's entry for "Adam's apple" for more details.--Screwball23 14 October 2005 3:03PM

weird equation

if p(x) = kx^3 + (2k^2)x^2 + k^3, what is the sum of all real numbers k for which x-2 is a factor of p(x)?

Bobby

i hope this doesnt show up at the bottom again.....

Three things:

1. Questions are supposed to go to the bottom, newest at the bottom, oldest at the top :P
2. We don't solve homework-questions!
3. Even though we don't solve homework questions, I took a stab at solving it (my mathematical vein flexed, even though it hasn't been used for a while). If you want a hint, realise under what condition have to be met in order to (x-2) to be a factor of p(x). You can find that out using divison, although not the ordinary kind. gkhan 16:37, 14 October 2005 (UTC)

synthetic division perhaps?

Are you implying that people only do math when it's homework?!? I'm offended! -- Ok, not really, you're completely right. ;-) --Quasipalm 19:47, 14 October 2005 (UTC)

--Try inspection. Looks like Advanced Subsiduary level maths in the UK, type of question. Grade B probably.

DJK

what is Backint

What is the context (where did you hear this word) ? StuRat 19:54, 14 October 2005 (UTC)

health

my daughter ,13 years old ,basically T-ALL patient,on maintanence,had Toxoplsmosis infection on the pons region of brain,about 30mm in size(MRI),resulted in impaired function of gaze,gait and speech,took medication (sulphadiazene+pyrimethamine+folinic acid)for about 42days,showed significant reducation in the size of infection,and the rescent MRI showed the size of the infection is about 11mm in size. Though the infection has come down resonably,i have not noticed significant improvement, correspondingly, in her gaze,gait and speech.why? How long it would take for her to have normal health?

Just a guess on my part, but I would say the brain tissue which has been destroyed has not regenerated. Unfortunately, nerves do not always regenerate, but tend to do so more in children than in adults. I don't know if your daughter is too old for it to regenerate at all, or if it will just take a long time, ask your doctor about that. StuRat 19:59, 14 October 2005 (UTC)

People who suffer strokes often start off as cabbages but over time the brain rewires its self as best it can. I spent 6 weeks in hospital with a man who was brought in a total vegetable and who went out...well, nearly 100%. Not bad considering the state he was in. Remarkable thing ...the brain.

Also note that other parts of the brain may take over for the damaged part, but this may take time, speech therapy, and physical therapy to accomplish. StuRat 20:52, 14 October 2005 (UTC)

A neurologist with experience with this type of brain lesion can give you the best probabilistic answer to your question. This is as specialized a medical question as it gets, and all you get here are speculations about "if it doesnt improve this might be why". From your description I am assuming that your daughter is getting good care at a major children's hospital. If you have asked this question directly to your daughter's neurologist, you have probably gotten a much more accurate answer than we can give you here. If the answer may was unsatisfyingly vague, it is possible that her combination of conditions is too rare to provide probabilities, or that the range of probabilities is too wide to be anything but really vague. If you haven't asked the question, please do so. Good luck. alteripse 21:21, 14 October 2005 (UTC)

What age do most homosexuals discover their identity?

I hear differing ranges on this question, but I am interested by the number of people who discover their true sexual identities later and later in life, sometimes after being married and having children. This contrasts greatly with the adolescent/young adult psychosexual development model I had been taught. What is the exact age that most find out the truth about themselves, particularly in American society?

According to a recent story in Time Magazine, the average age has dropped into the teens. →Raul654 18:35, 14 October 2005 (UTC)

Middle-aged people who "discover" they are homosexual probably really knew so all along, on some level, but just kept it secret, perhaps even from themselves. Those who actually had no attraction to their own sex and then changed sexual orientations spontaneously in mid-life would be truly rare, and worthy of study, if they exist. I would suggest that some physical change has occured in the brain in such cases; perhaps a virus or some other disease has changed the nueral pathways. The same comment would be true of a homosexual who suddenly become a heterosexual in mid-life. StuRat 19:46, 14 October 2005 (UTC)

Anecdotal evidence to support this: a nominally bisexual acquaintance of mine told me once that she was attracted to other girls from early childhood, indeed long before she was aware of what homosexuality was. My belief is that many gays and lesbians know what they are from a very, very early age. Of course, I also believe that sexual orientation is not (for the most part) a choice, but a genetic issue, so I may be prejudiced.Brian Schlosser42 19:52, 14 October 2005 (UTC)

Another explanation is that they were bisexuals who just switched behaviours, but are still attracted to both genders, as before. StuRat 19:50, 14 October 2005 (UTC)

And yet another view. Notice how your question implies a couple of assumptions that represent current conventional wisdom but may be more culturally shaped than you think. Your first assumption is that homosexuality is a lifelong biological condition like a blood-type which is always there but gets discovered and recognized as the "true self" at some point in time, sort of like finding out what your blood type is. Your second is that this is the "true" identity, and conversely their earlier identities and behaviors were therefore "false". This is the "essentialist" (born that way) position and has not always been a universally accepted way to think about homosexuality. Another way to look at it is more complex, and involves distinguishing concepts like (a) self-identified cultural roles from (b) degree of attraction to potential partners of a specific sex, and (c) recognizing that cultural and other environmental factors may influence the response to such feelings, and (d) the interpretation made by the person and those around him/her. This distinction may be especially applicable as a way to think about adult changes of preferred sexual partner. In an oversimplified nutshell, this is the distinction between "homosexuality is what someone is" and "homosexuality is what someone does". The essentialist/constructionist debate is not consistently "mappable" to liberal or conservative politiics: 30 years ago, the idea that there were biological factors strongly determining a homosexual identity was anathema to the gay left and politically correct academics. Now the fashion has swung the other way, but history suggests it will change again, and many people are skeptical that there will be a simple biological "born that way" explanation discovered.

This is a controversial topic and the average age of wikipedia contributors ensures that most will not know how vehemently people from 30 years ago of the same age, same education, same politics, and same gay-supportive attitudes would disagree with them over this. alteripse 21:09, 14 October 2005 (UTC)

I am convinced that "sexuality" lies on a spectrum. And as in the colors of a spectrum there is no dividing line but rather a gradual merging from one color to another. And such is sexuality. Society on the other hand has no patience for this kind of explanation preferring instead to have tidy little boxes and labels. This lack of patience for reality does in fact result in premature self-identification into one of the boxes along with its self-perpetuating requirements, obligations and predjudices. --hydnjo talk 23:35, 14 October 2005 (UTC)

A certain feminist theory (not that i particularly agree with it) reckons that sexual preferences can be learned, thus making the age at whenever one begins practicing homosexuality. A prominent fem-activist (i forget her name) said she learnt to be a lesbian, which she felt she had to do because otherwise she wasn't really a feminist. This was when she was in her thirties or thereabouts after living a previously straight lifestyle. --Ballchef 01:00, 15 October 2005 (UTC)

Which is exactly what I'm talking about. Being put into a set of expectations, regardless of feelings, until maturity catches up (if ever) and one faces their own place on the spectrum of sexuality. --hydnjo talk 01:25, 15 October 2005 (UTC)

As the responses so far show, this isn't an easy question to answer. I've met gay men who say that they've always known they were gay, but until their teens they didn't know that there was a word for it or that it had to do with sex. And, I've met gay men who say that they "realised" they were gay far later in life after a series of unsuccessful relationships with women.

You might look for an answer by turning the question around: When did you realise that you were straight? Is there any simple answer to that question?

I'm one of the people who think that there is probably no simple biological cause for homosexuality - I don't think it's hereditary or a chemical imbalance or something of that ilk - and I don't think it is genuinely learned or chosen by any sizable gay population. Humans are full of preferences that don't have clear biological or environmental roots. When you flip a coin there are only two possible outcomes, and which one you get depends on a dizzyingly large number of environmental factors and is very sensitive to very small perturbations in the environment. You can not say that some simple cause X causes the coin to land one way and not the other. In the same sense, I think human sexual preferences are the product of dynamic processes which lead to a finite number of relatively stable outcomes but where those outcomes cannot be realistically determined or modified by control over a person's environment. If true, this means there are an indeterminately large number of possible life histories that lead to being gay just as there are for being straight and that no generalisations can be extracted from their study.

--Diderot 11:53, 15 October 2005 (UTC)

I’ve seen some male animals trying to mount other male animals usually unsuccessfully. This is probably as a result of sexual pressure… the dreaded urge to copulate…but this doesn’t make that animal gay. The normal condition of all animals is to lean towards heterosexuality. I would assume that includes humans. I’ve never seen any female animal show signs of being a lesbian so one must conclude that human homosexuality is the result of the human condition and not as a result of any biological or evolutionary condition. Unless there are gay animals about? --Eye 21:47, 15 October 2005 (UTC)

There are plenty of animal models of homosexual mating preference. For example, look up some of Chuck Roselli's papers about gay rams. alteripse 00:09, 16 October 2005 (UTC)

See Non-human animal sexuality, in particular the sections on Sheep, and the Spotted Hyena.-gadfium 00:34, 16 October 2005 (UTC)

venomous snakes

My 6 year old son asked me if venomous snakes can kill other snakes. Can they and if so - do they? I can find no information on this. Thanks. Shelley --69.205.133.224 18:44, 14 October 2005 (UTC)

Snakes eat other snakes which usally leads to the death of the eaten snake. Being venomous usally helps in the killing but isn't always necessary --Eye 19:32, 14 October 2005 (UTC)

Snake has the answer and the answer is yes, venomous snakes eat other snakes and they use their venom to kill their prey (including other snakes):

All snakes are carnivorous, eating small animals including lizards and other snakes, rodents and other small mammals, birds, eggs or insects. Some snakes have a venomous bite which they use to kill their prey before eating it. Other snakes kill their prey by constriction resulting in death by strangulation. Still others swallow their prey whole and alive.

Another interesting question would be, If a snake gets bit by another snake with the same kind of venom, will it die? --Quasipalm 19:45, 14 October 2005 (UTC)

How could it? Venomous animals must be immune to their own species's venom, right? How else could their bodies produce it? Brian Schlosser42 19:54, 14 October 2005 (UTC)

Not necessarily. The poison they produce is kept in a special poison gland, not in their blood. For example, the hydrochloric acid we produce in our stomachs is quite poisonous to many types of bacteria, and would be so to us, if it were injected into our bloodstream with fangs. However, in a properly functioning stomach, with a nice mucus lining, it's not a problem. This said, many species will have at least a partial immunity to their own poison, as battles with other snakes of their own species are common, and such immunity would therefore be advantageous. If they eat prey which they have injected with their own poison, they will also ingest some that way, although it will be far more dilute by the time it has spread throughout the victim's body. Some types of poisons, like nuerotoxins, can more easily be defended against, say by blocking the nueroreceptors for that toxin, than others, like strong organic acids. StuRat 21:03, 14 October 2005 (UTC)

A little googling finds some interestring but contradictory results. A bunch of tiger snakes and copperheads thrown in together may eat each other but are immune to each other's venom [16]. Vipers and rattlesnakes have blood components that neutralise their own venom but cobras have a protection at the DNA level: their venom has a neurotoxin that doesn't match their own receptors [17]. Or, conversely, "The Prairie rattlesnake is not immune to it’s own venom" [18]. Notinasnaid 07:26, 15 October 2005 (UTC)

Chemistry lecture

A couple of times (once in high school, once in college), I saw a demonstration in which a solution was created then allowed to sit for a few minutes. At a certain time (which apparently can be predicted through calculations), the solution instantly turned from colorless to black. What components were used, and what is the mechanism which causes the color change?

Sounds like the "blue bottle reaction" in reverse. That one is NaOH, glucose & methylene blue, which starts out deep blue, and gradually fades to colourless. Shaking it makes it blue again. --Bob Mellish 19:08, 14 October 2005 (UTC)

The reaction is called the iodine clock reaction, and yes we really ought to have an article on it! In the meantime, a Google search will show you plenty of sites with videos etc. The chemistry is quite simple, there are two reactions involved:

2I⁻ + H₂O₂ + 2H⁺ → I₂ + 2H₂O (slow)

I₂ + 2S₂O₃²⁻ → 2I⁻ + S₄O₆²⁻ (fast)

All the time there is thiosulfate present in the mixture, the iodine is reduced as quickly as it is formed. Once the thiosulfate has all reacted (it is the limiting reactant), the concentration of free iodine (or strictly of the triiodide ion) increases and gives the characteristic blue colour with the starch which is also in the solution. This site gives a description of the Briggs-Rauscher reaction, which is similar in principle but which oscillates backwards and forwards between dark blue and colourless. Physchim62 19:20, 14 October 2005 (UTC)

Stub created! --Quasipalm 19:38, 14 October 2005 (UTC)

Eaten Up

Why do we eat? I know that we eat to live and if we do not eat we would die but dieing only explains what would happen if we did not eat it does not explain why we do eat.--Eye 20:12, 14 October 2005 (UTC)

The main reasons we need to eat are: 1. Food contains energy as sugar, carbohydrate and fat. Without this energy, our muscles cannot move, our brain cannot work and our cells cannot grow. Therefore you die. 2. Food has lots of proteins. These long strings are broken down into smaller chemicals which are then used to make up important organic chemicals such as DNA. Without this, you die. 3. Food also contains salts, vitamins, minerals and other chemicals, such as iron, calcium and vitamin C. These are vital to help our body to keep itself running properly, and without them, our organs, blood, muscles and bones would stop working correctly and cause you to die. smurrayinchester^{(User), (Talk), (Recent Contrib)} 21:34, 14 October 2005 (UTC)

From an evolutionary approach, I would say that organisms which lacked the desire to eat died before passing on their genes, so those that are left largely have this instinct. There are still some individuals who are able to suppress this instinct, such as those with anorexia, but those genes may be selected against after some of them die childless. As for how the desire to eat developed in the first single-celled animals, I would say it developed over time. A plant cell absorbs nutrients from it's surroundings. An animal cell has the ability to move, and eating may have initially just meant moving to an area high in nutrients and absorbing them. The next step may have involved releasing an acid when in the neighborhood of such nutrients to aid digestion. The next step may have been to enclose the nutrient in a vacuole (a sphere inside the organism), and then adding digestive fluids to the vacuole. This might be the first thing that we would recognize as "eating". Next came a tube shaped digestive system, then came all the rest. StuRat 21:45, 14 October 2005 (UTC)

Or, we eat because we are hungry. Unfortunately, our article on hunger doesn't make much of this. - Nunh-huh 02:27, 15 October 2005 (UTC)

OK.Why do we get hungry? :-)--Eye 21:02, 15 October 2005 (UTC)

Ok, now I am guessing you are asking why we get hungry when we seem to have had enough to eat. This is a consequence of evolution. For most of human history, starvation was a threat, so putting on fat whenever we could was a good survival strategy. Salt, protein, fat, and cholesterol were hard to come by but vitamins and fiber were in abundant supply. So, those people who craved as much salt, protein, fat, and cholesterol as they could find tended to survive and pass on their genes. Those who preferred grains and veggies tended to die from starvation. Now, we are stuck with those cravings, despite having all the bad stuff we could ever want at our fingertips. Don't worry, in a few hundred thousand years evolution should catch up to our current food supply. StuRat 22:54, 15 October 2005 (UTC)

Perhaps this is just me - I could stand to lose a few pounds, I know - but I sometimes eat for fun. Food tastes good, be I hungry or not, and I'm pretty sure my attachment to cheesecake transcends the explanatory power of any current theory of evolution. George 21:06, 15 October 2005 (UTC)

DDT

How is dichloro diphenyl tricholobenzene produced? What chemicals are needed to synthesize the chemical

Does the article DDT help at all? --hydnjo talk 21:27, 14 October 2005 (UTC)

It is not specific enough.

Neither is your question! DDT is produced by the reaction of trichloroethanol with chlorobenzene. What else do you want to know? Physchim62 09:14, 15 October 2005 (UTC)

Please not that [[DDT] is a toxic and banned substance. DO not try to produce it! AnyFile 15:55, 15 October 2005 (UTC)

I know that DDT is made with trichloroethanol and chlorobenzene, but I am a grade 9 student, I am doing a project on DDT can you give me some information on these three chemicals?

why do I suffer from sole and heel pain from jogging and walking?

Do you suffer from Diabetes (Diabetes mellitus)? I don't mean to make this into a "20 Questions" thing but am just asking the about one of the more obvious causes for this kind of pain as a rough triage. --hydnjo talk 23:05, 14 October 2005 (UTC)

I've read once about a condition where the heel bone presented a spike-shape. This caused acute pains on the sole and heel. \ Edit: Found it. The condition is called heel spur [19] ☢ Kieff | Talk 23:17, 14 October 2005 (UTC)

It may not be a medical condition—it's possible that your shoes aren't appropriate to the activities you're engaging in. Particularly if you're jogging on a hard surface like concrete or asphalt, you can do unpleasant things all the way up your leg and into your back. TenOfAllTrades(talk) 02:58, 15 October 2005 (UTC)

• Wikipedia does not give medical advice. →Raul654 03:02, 15 October 2005 (UTC)

• Thanks for bringing this to our attention. I forgot and got wrapped up with the question. :-( --hydnjo talk 03:20, 15 October 2005 (UTC)

• As stated in our guidelines, you should speak to your doctor and see what he or she says.Capitalistroadster 07:33, 15 October 2005 (UTC)
  • The disclaimer doesn't state that we can't give our own medical opinions though, does it? I see a lot of answered questions on the desks that refer to legal or medical matters, we're not gonna get in trouble for it surely? --Ballchef 07:49, 15 October 2005 (UTC)
    • No. We just have to point out that it's not official advice, and they should check with a real doctor/lawyer before doing anything. Superm401 | Talk 23:15, 15 October 2005 (UTC)

Some points concerning wikipedia "medical advice":

1. Do respond to questions with generalities: "the common causes of your symptom are"
2. Do use the subjunctive; this is what it's for.
3. Do always indicate the hypothetical/probabilistic nature of your response or the level of confidence in it (which might not be high).
4. Do think of your answer as telling them what to expect from a doctor, not as a substitute for seeing a doctor.
5. Do remember how often first answers here get corrected or modified.
6. Don't forget that people often omit a crucial detail, and the story might change substantially after some questioning.
7. Don't tell them how to treat themselves. Tell them what a doctor might suggest for a similar problem.
8. Don't ever give anyone grounds for saying "he disuaded me from getting medical attention."

It never ceases to amaze me that people will have their insurance company spend $250 for them to explain exactly what is wrong to a person who is trained to help, experienced with that kind of problem, and responsible for what he recommends. And yet they sometimes think free advice based on 1 minute of consideration of 2-5 pieces of information by anonymous strangers with unknown training, experience, and no responsibility for what happens would trump it! alteripse 00:03, 16 October 2005 (UTC)

Helianthus anuus

What water, nutrient and soil requirements are needed to grow Helianthus anuus in a glasshouse environment? sarah

Do you mean Helianthus annuus? If so this is from a Google search. Our article Helianthus annuus may also be of some help about growing Sunflower. You'll also need a tall glasshouse/greenhouse! --hydnjo talk 00:28, 15 October 2005 (UTC)

Self-sustainment

Could a species, without outside food sources, sustain itself on its own dead? The example I have in mind is cockroaches. ♥purplefeltangel ^(talk) ♥ ^(contribs) 05:00, 15 October 2005 (UTC)

Define "sustain itself". For how long? I guess, depending of the species, cannibalism could keep a few alive for a while, but that wouldn't last long enough... The population would drop at a decreasing rate, though. ☢ Kieff | Talk 06:16, 15 October 2005 (UTC)

Define "outside food source". If you count the sun as an outside food source, the answer to your question is "No".

I suppose you mean something like biosphere II without the plants. Nutrients are lost through feces. If these are not transformed to something edible for the animals (whcih plants do) then the population will eventually strarve to death. DirkvdM 09:24, 15 October 2005 (UTC)

Yes. Bacteria are really good at this. Fungi less good but using spores can decrease their need to eat to as close to nothing as you want. Insects can survive a very long time on very little. Snakes (some or all?) can respond to little food by using nearly all their own tissue (and regenerate it later). Imagine a giant meteor hits Earth, kills the dinosaurs, and puts the Earth in a dark winter for decades. Plants die. Everything big dies. Most warm blooded things die. Life forms that eat dead and decayed stuff (the insects) do well. Insect eaters survive. Maybe a few eaters of insect-eaters survive. The exact answer for your question requires a specific species, number of living initially, and lengh of time. Millions of roaches could last centuries I would guess before the last two died. 4.250.198.246 09:55, 15 October 2005 (UTC)

Yeah, but in the end they'd all die, so the answer is still no then. If a meteor would kill everything except bacteria they would survive because of the different metabolisms of different bacteria (some producing oxygen, others comsuming it and such). But there's also the possibility of evolution. If they could survive off each other for long enough then maybe enough different bacteria could evolve to produce a complete ecosystem again, with fully complementary metabolisms. DirkvdM 10:58, 15 October 2005 (UTC)

That doesn't get round the problem of the Second law of thermodynamics. Life is fundamentally organised; to create this organisation from less organised starting materials, it must "spend" energy. For the vast majority of life on Earth, the ultimate source of this energy is the Sun. No sun, no life (eventually), except if you have adapted to live in a hydrothermal vent. Physchim62 14:17, 15 October 2005 (UTC)

Okay, this is the specific scenario I had in mind: Everything on Earth dies. But the roaches, because they're smart like that, move to another planet. There are no other species on this planet, but there is a light source and there is water. If every roach on Earth was living on this planet and they ate their own dead -- at first killing the weakest, but later on eating those who die of natural causes, wouldn't they be able to sustain themselves indefinitely? Don't forget that cockroaches can have up to four hundred babies at a time. ♥purplefeltangel ^(talk) ♥ ^(contribs) 18:35, 15 October 2005 (UTC)

The amount of babies is irrelevant. If there is not only no food source but no other energy source either then you get a biosphere II with only cockroaches and even wthout the sun coming in. That means they have to find a way to convert their lost energy into a form they can consume again. And for that they need plants. Cockroaches are much further developed than bacteria and therefore not quite as flexible. They are notoriously resilient, but I dont' see them pulling this one off. Maybe you should stop watching MIB. :) DirkvdM 18:51, 15 October 2005 (UTC)

Never even seen that movie. :P This grew out of a discussion about the armageddon with one of my friends. User:Purplefeltangel/sig 19:22, 15 October 2005 (UTC)

The roaches would have to (re-)evolve photosynthesis, and fast! Bacteria in culture cannot manage it (they all die if you starve them), so I don't expect that roaches would be able to either. Physchim62 19:39, 15 October 2005 (UTC)

A tight budget, no patience and a stack of reading to scan so it can _still_ be read.

What sort of page scanning speed can one expect given the following:

• A fairly low-end scanner.
• A resolution good enough to give an image able to pick up average newsprint font size and reproduce it so it's easily readable to the eye (no OCR involved).
• A desire not to have to be very careful about lining up each page on the flatbed.

Essentially, it occurs to me I have lots of reading material I'd like to get rid of (to give me more room and for profit) and I'm wondering how quickly I could scan through the entirity of an old magazine but keeping the filesize/time down. --bodnotbod 07:18, 15 October 2005 (UTC)

Another consideration. How much time would it cost, how much is your time worth (assuming that time is money) and how does that compare to the cost of the space you'd need to keep the magazines. If you don't need to access them regularly you could stow them away in a box so that it doesn't effectively take up space (depending on your living conditions of course). Let's say one scan would cost a half minute. That's roughly 100 pages per hour or one magazine per half hour. One average box of magazines would contain about a hundred. That's 50 hours. Assuming you value your time very low, at 5 euro per hour. That would be 250 euro. How long can you store one box for that? Assuming that is one month's rent for a house that is 30x30x30=10.000 times bigger than the box. So you could store the box for 10.000 months for that price. That's well over 10 lifetimes.

This is assuming you can't do anything else while you're scanning, which is pretty much the case. Believe me, I've tried this sort of thing - even doing the scanning while working on the Wikipedia reference desks wouldn't really work. Another option would be to build a contraption that turns the pages and does the scanning automatically, like the ones used by libraries that are digitising their books. Or maybe you could hire some time on one of those machines. Ask at a library. Who knows. DirkvdM 09:41, 15 October 2005 (UTC)

If I were going to do this, I'd want to score a scanner that did two-sided scanning and had a sheet feeder like most copy machines have. That way, you could just cut all the pages of the magazine off of its binding and shove 'em in the sheet feeder. However, we're beyond "fairly low-end" scanners at that point. Garrett Albright 17:01, 15 October 2005 (UTC)

Bear in mind you talking about something potentially illegal here. The publications are copyrighted. This means you purchased ONE copy. If you scan the media into computer, then dispose of the original dead tree copies, you now have created two copies (even though you got rid of one, either by give away or sale), perhaps #3 as backup, which violates you bought one. You could physically destroy the original media, and be in compliance in spirit but then if the copyright police find you in possession of the scanned copy, you'd need to prove you destroyed the original, which can be difficult to prove without the destruction evidence. AlMac|^(talk) 19:06, 15 October 2005 (UTC)

How can you tell if a plant is male or female?

My 8 year old daughter has chosen this as her independent research project at school. I have used Google and Yahooligans to search for info but can find nothing that explains it simply enough for her (and me) to understand. Any help would be gratefully received.

Have a look at the article on plant sexuality. For an example of a plant that is unisexual (which means it has a "reproductive structure that is either functionally male or functionally female"), see begonia. David Sneek 09:24, 15 October 2005 (UTC)

For some nice pictures, see stamen and carpel (respectively the male and female sexual structures in plants). Physchim62 09:29, 15 October 2005 (UTC)

Flowers are the most reliable indication to discriminate between species (if they have flowers at all), so I assume the same will be true for discriminating between sexes. But flowers differ enormously between plants, so I don't think there will be many general indicators. The most obvious one is that male flowers produce a powdery stuff called pollen, but that is only during a very short time in the lifecycle of the plant. Other than that, I know that in hemp the female leaves are usually somewhat braoder than the male leaves, but that also varies between varieties of one species, so it's only a very vague indicator unless you know which variety yo're dealing with. DirkvdM 09:57, 15 October 2005 (UTC)

Fruit is only produced by female plants. It is defined as the ovary of a female plant, containing either fertilized or unfertilized seeds (ova). However, there are other things that look very much like fruit, produced by other plants. StuRat 22:42, 15 October 2005 (UTC)

I do know that if you crowd dope plants together they will produce largely male plants but a single plant grown on its own will more often than not grow into a female. The logic behind it is because a crowd of females will drop their seed in an area already populated by dope plants. The result is the species does not spread far. However if a seed does find its self on its own and thus in an area not populated by dope plants it would be best to turn into a female to catch wind blown pollen from the group of males. We are not talking huge distances here but what the heck who's in a hurry :-)--Eye 21:17, 15 October 2005 (UTC)

Electricity

If electricity is defined as a flow of particles, electrons or whatever does this imply it has some sort of volume? If so what volume is reduced when electricity flows and how was it created. I have some understanding of comparisons with hydraulic systems when talking about electrity flow and pressure.60.229.174.15 10:48, 15 October 2005 (UTC)

In hydraulic terms, electricity is essentially incompressible. However some materials do change volume when electricity flows through them: see electrostriction. Physchim62 14:21, 15 October 2005 (UTC)

Thanks. But I am still having trouble with this volume and substance thing

Mass of bacteria in the human body

Does anyone know what mass fraction of the human body is composed of bacteria? That is, if you took all the bacterial cells out and weighed them, how much mass would that be compared to the mass of the whole body? —Keenan Pepper 16:59, 15 October 2005 (UTC)

Just to clarify, I'm talking about a normal, healthy human, although I think you'd have to have quite a bad infection to significantly add to the mass of normal bacteria. —Keenan Pepper 18:17, 15 October 2005 (UTC)

It depends on whether you include Mitochondria. These were originally proteobacteria, a major group of bacteria that started living in symbiosis with other lifeforms so early that most now have hem in every cell of their body, where they take up 25% of the internal fluid of those cells. And since we consist fully of cells and fluid constitutes the major part of our weight you could say that they constitute some 25% of our weight. (Although I'm not sure every cell has them, such as in bones.) But that's probably not what you were thinking of. DirkvdM 18:33, 15 October 2005 (UTC)

Oh right, I didn't even think of that. But besides mitochondria, what's the mass of all the "true" bacterial cells? Bacteria in the human body says there are about 10 times as many as human cells, but what is their average mass? —Keenan Pepper 18:43, 15 October 2005 (UTC)

Using the article you linked to above and this webpage [20] you can calculate 1x10¹⁵ x 1x10^-12g = 1x10³g or 1kg. I think bacteria can range in weight a fair bit. No idea how close to right this is. --Martyman-(talk) 23:38, 15 October 2005 (UTC)

Nearly all the bacteria are topologically outside our body: on the skin, and in the gastrointestinal tract. Intestinal contents do not acquire a large bacterial component until they reach the colon, but bacteria do represent a substantial fraction of feces (though less than half of the fecal mass). So maybe a kg worth of bacteria in your colon at most, probably less. While we have zillions on our skin and in our mouth, they would probably not add up to more than an ounce (30 g) by themselves. There should be no significant amounts amounts of bacteria anywhere else in your body. alteripse 00:17, 16 October 2005 (UTC)

Overheated Glass

What happens when glass overheats? Does it expand? What are the hazards of a glass pot left on a hot stove, and would it be safe to pour water in it?

If you heat glass to a high enough temperature (1000-2000°C), it will simply melt. Your stove probably doesn't get anywhere near that temperature, so your glass pot can't "overheat". Pouring cold water in it is a different story, because glass does expand when heated, so a rapid change in temperature may cause it to crack as some parts contract faster than others. —Keenan Pepper 17:23, 15 October 2005 (UTC)

Glass does of course expand when heated, and contract when cooled, which as Keenan Pepper explained, could cause cracking. However, if the glass was extremely hot(unlikely), the water poured could become steam and possibly cause steam burns. Superm401 | Talk 20:27, 15 October 2005 (UTC)

I've had a coffee pot crack because the glass has a different rate of expansion than the metal band around the neck of the pot. StuRat 22:35, 15 October 2005 (UTC)

Musical Statues

Why is it so difficult to remain perfectly still? If someone tries not to move a muscle, they end up twitching or shaking. Surely it should be easier to stay still than to move! smurrayinchester^{(User), (Talk)} 17:18, 15 October 2005 (UTC)

Nothing is ever still--Eye 17:31, 15 October 2005 (UTC)

Even when you're trying to keep some part of your body still, your muscles are pulling on it from different directions. If the muscles aren't perfectly in balance, it will move to one side or another. That explains why it's easier to keep your arm still if it's hanging at your side (muscles mostly relaxed) than if it's raised above your head (muscles pulling in opposition). Also nerves have a lot to do with it... —Keenan Pepper 17:33, 15 October 2005 (UTC)

Web technology

I'm opposed. George 21:00, 15 October 2005 (UTC)

I agree. Web technology sucks. gkhan 23:15, 15 October 2005 (UTC)

Earth and sun

How fast dose the earth spin around the sun? Name:aidan McCarthy Age:8

• The Earth takes one year to go around the Sun.
• The Earth takes one day to go around itself.

AlMac|^(talk) 19:10, 15 October 2005 (UTC)

The Earth revolves around the Sun once a year, and it's 150 million kilometers away, so the total distance it travels in one year is 2 times pi times 150 million kilometers, or almost a billion kilometers every year. That means its speed in relation to the Sun is about 30 kilometers per second. In other words, really really fast! —Keenan Pepper 19:14, 15 October 2005 (UTC)

The Wikipedia article on Earth has a lot more facts about the Earth, like how big it is and how much it weighs. —Keenan Pepper 19:18, 15 October 2005 (UTC)

The weight?? Don't you mean "mass"? Dismas|^(talk) 00:12, 16 October 2005 (UTC)

Well, it weighs something in the gravitational field of the Sun, right? That's why it's falling (accelerating) toward it. But you're right, I meant mass. —Keenan Pepper 01:35, 16 October 2005 (UTC)

MSN Messenger

Is it possible to figure out when your contacts come online?

• Apart from the message you get when a contact gets online? - Mgm|^(talk) 20:45, 15 October 2005 (UTC)

I am guessing they meant ot ask when they came online, 20 minutes ago or 20 hours ago ? I suspect it could be done if you when online when they came online, as a signal is sent to your computer. However, if you weren't online when they came online, no message is ever sent to your computer, which would make it a lot more difficult. StuRat 22:06, 15 October 2005 (UTC)

The popular Messenger Plus plug-in includes an event log (click Plus > Event Log Window) which shows when contacts come online, change their status, and go offline, all with times. --Sum0 23:18, 15 October 2005 (UTC)

Do note, however, that if you use this, DO NOT install the sponsor. --Pidgeot (t) (c) (e) 23:45, 15 October 2005 (UTC)

Muscular Force

Could someone please tell me what the average force exerted by the brachial muscles (the deltoid to the phalangeal adductors) on an object is?

Michael P. Barrett --86.128.76.18 19:58, 15 October 2005 (UTC)

• How much can you lift in a bench press? Multiply the weight in kilograms by 9.8 (or the weight in pounds by about 21.5) to get the force in newtons. Physchim62 20:12, 15 October 2005 (UTC)

Topology

An anon posted this message in WP:HD. I moved it to here. --User:Mdob (note: there are other messages too, move them to here if you have patience, thank you)

Regarding the metric space and topological group.

Question : Is metric space with group structure topological group?

PDF autocropping/rotating?

Are there any programs out there which can automatically rotate and crop PDFs down to their main body of text? I download a lot of things off of JSTOR for my studies and I like to print them 2 X 2 to a page, but to do so requires first getting rid of the extra page margins on each page (otherwise the text is printed far too small to read). If I could automate this, it would be great, but I can't seem to be able to do it with any of the programs I have (which includes Adobe Acrobat Professional 7.0). Is there anything out there which can do this? It seems like it would be a not-too-difficult feature to make, on the scale of things. I tried using the "Remove White Margins" setting on the "Crop Pages" screen in Acrobat but that does not seem to do anything at all with JSTOR files. --Fastfission 00:44, 16 October 2005 (UTC)

How Electrons Stay In a Probability Field Around a Nucleus

How do electrons stay in their probability field without going anywhere? It can't involve strong nuclear forces (mostly inside the nucleus), weak nuclear forces (too long a distance) or gravity (too weak for the masses involved), so I can only assume that they are kept in check by exchanges of messanger photons. Is this correct?