Wikipedia:Reference desk archive/Science/2006 July 1

From Wikipedia, the free encyclopedia

Humanities Science Mathematics Computing/IT Language Miscellaneous Archives
The page you are currently viewing is an archive page. Whilst you can leave answers for any questions shown below, please ask new questions at one of the pages linked to above. This will insure that your question is answered more quickly.

< June 30 Science desk archive July 2 >


Contents

[edit] Japanese Giant Flying Squirrels

I'm not sure this is the right place to go, but if you look at the article on Japanese Giant Flying Squirrels, it says that during reproduction, the male produces a "coitus plug" after ejaculation which apparently is a sticky protein substance that blocks the female's vagina. I haven't been able to find this on google, so I'm wondering if this is an instance of vandalism, or if it is indeed true. (And if it is true, I suppose my next question would be whether other species of capable of this.) --Jinnentonik 23:19, 1 July 2006 (UTC)

The article Japanese Giant Flying Squirrel appears to be based on ja:ムササビ, which doesn't cite sources either. I'll hit it with a cleanup tag and see what shakes out. Melchoir 00:22, 2 July 2006 (UTC)

It's not vandalism. Squirrels and many other rodents employ them; some non-rodents as well. More often called vaginal plug, sometimes copulation plug. [1] There seem also to be human sex toys and such with similar names. -R. S. Shaw 21:59, 2 July 2006 (UTC)

[edit] Smokescreen - how can I make one?

I recently got into the sport of airsoft, which is a game with guns that shoot plastic bullets and with scenarios similar to real combat, and I decided to become a sniper. Being a sniper, a smokescreen would make getting in and out of buildings or around enemy airsofters much easier. Now, I'd like to know if there is any substance, no matter what state of matter, that will form smoke when put under flame or mixed with another substance. I would prefer powder or liquid, because they would be a lot easier to control, as gas would have to be bottled and kept under pressure and such, but I'll take any answer. Also, this substance, when turned to smoke, must be completely safe to humans. I can understand that breathing anything other than oxygen isn't good, but I'm talking about things like puking or bleeding or long-term side-effects like Alzheimer's Disease and cancer and the like, because I will be running through this smoke almost every time I deploy it, and I definately wouldn't want to hurt anyone else who breathes it.

-Jacob

I'm not sure I understand, are you going on some sort of snipe hunt? also pure O2 is corrosive, there's plenty of inert elements in the atmosphere to buffer it--71.249.29.10 01:07, 1 July 2006 (UTC)
Where did you get that O2 is corrosive? O2 is toxic at very high concentrations, but that's why most oxygen for human consumption is mixed with nitrogen or helium (in different amounts). --ColourBurst 07:34, 1 July 2006 (UTC)
Try reading the article smoke bomb. It states very clearly what is mixed to make smoke in real smoke bombs (which smell like burnt marshmellows, but are not, to my knowledge, toxic). --Kainaw (talk) 01:20, 1 July 2006 (UTC)
I don't want to put up a Smoke-screen, but I guess Jacob does - Johntex\talk 02:04, 1 July 2006 (UTC)


Dry Ice makes a fair amount of smoke when mixed with water. Neither of the two is harmful aswell. Philc TECI 02:05, 1 July 2006 (UTC)
Byut dry ice has to be kept cold. I wouldn't have thought it would be very easy to transport. Theresa Knott | Taste the Korn 07:42, 1 July 2006 (UTC)
Fire work suppliers will sell 'smoke grenades'. Trollderella 15:20, 5 July 2006 (UTC)

[edit] annulation of auditory communication incorporating instrumental or vocal tones in a structured and continuous manner?

How long can you listen to the same piece of music loop non-stop before you become insane, ...clinically?--71.249.29.10 02:49, 1 July 2006 (UTC)

  • PS, this is a serious question--71.249.29.10 02:49, 1 July 2006 (UTC)
I don't believe there is any single point at which every person will suddenly snap from sane to insane. However, you can read a lot about the effects of using music as torture. Just google for "music torture". I escpecially loved an article read that stated Marines used Barney's "I Love You" song as torture in Desert Storm. --Kainaw (talk) 03:01, 1 July 2006 (UTC)
If the song's by Whitney Houston, the time's about 25 seconds. For Crazy Frog, it's only 20. Grutness...wha? 13:38, 1 July 2006 (UTC)

[edit] Boric acid level of toxicity

I've heard that Boric acid is no more toxic than table salt. Is this true? Can I consume as much Boric acid as I do table salt without ill effects? ...IMHO (Talk) 02:50, 1 July 2006 (UTC)

  • I'm thinking NO investigated as a mutagen, tumorigen, reproductive effector. May impair fertility. May cause harm to the unborn child, at least not if you're planning on having children with the correct number of chromosomes, hey, but at least it's not a carcinogen--71.249.29.10 02:56, 1 July 2006 (UTC)
WOW! The above link says that only 5 grams is fatal. What is the lethal dose of table salt? if it is greater then I need to find the article I saw this in and delete the heck out of it. ...IMHO (Talk) 04:01, 1 July 2006 (UTC)
I'd answer that, but table salt doesn't seem to have a lethal dose (: --71.249.29.10 04:22, 1 July 2006 (UTC)
Yes it does - it says "Toxicological Information Oral rat LD50: 3000 mg/kg". So, for rats, 0.3% of their body weight in salt was the LD50 Also, on the corresponding Granular Boric Acid MSDS, it says "Oral rat LD50: 2660 mg/kg", which as you can see is indeed slightly less. So, at least for rats, granular Boric Acid is in fact slightly more poisonous. Although, for all we know, that's within experimental error, so it's safe to say they are of similar toxicity. For the record, i'd like to say that the rat LD50 is a abhorrent disgusting violation of animal rights and basic human decency, and should be banned. Now that i'm done citing it. -- 18.239.6.57 04:50, 1 July 2006 (UTC)
Oh well practically everything is fatal if you consume enough of it per body weight, techincally it still doesn't have a lethal dose, and for the record I don't think I've ever heard anyone object to the idea of an LD50 before, would you prefer they test human subjects? or simply deregulate all potentially hazardous compounds?--71.249.29.10 05:07, 1 July 2006 (UTC)
Haha. You're confusing the issue with drug testing, a very different issue which I will not write about right now. Basically, for dubious benefit to mankind, god knows how many thousands of rats and other mammals are subjected to long, painful deaths to find out the LD50 of each chemical via inhalation, injection, ingestion, etc. I mean how many rats needed to be tortured to death to tell us the LD50 of table salt??!! It's a sick, sick way to do research.
And what does it tell us? How much of that chemical it takes to kill rats 50% of the time. Note, rats, not humans - in fact studies like this one seem to indicate that animal assays are in many cases less reliable than other methods like in vitro assays using human cell lines. Don't assume it's necessary just because everybody does it. For a long time not so long ago 'leeching' was the gold standard in western medicine for most ailments, so let's not get too cocky about our traditions, mmm? --Bmk 06:55, 1 July 2006 (UTC)
LD50 is controversial, and not just with a fringe. LD50 indicates that some major international bodies (like the OECD) have taken steps to reduce its use. The article could use more discussion of this (e.g. coverage of their reasoning and any scientific background to their announcement). Notinasnaid 07:41, 1 July 2006 (UTC)
Animal assays are always somewhat controversial, but objecting to them on the basis of a misguided sense of animal rights is a bad reason to oppose them. It is far better for everyone—including animals—that humans have a good knowledge of how toxic things are. In the end it leads to a lot less suffering all around, such as when humans spend huge amounts of money to clean out toxic leaks into animal habitats. If you want to cry about mistreated animals, consider focusing on bigger targets like factory farming and cosmetics testing and things which appeal to human gluttony and vanity. Medical research on rats is probably one of the last things a responsible animal rights movement should target, when they honestly have nothing left to do. --Fastfission 22:00, 1 July 2006 (UTC)
The way government contracts work is probably the reason behind this method of research. It starts with a lab that tests pesticides on rats to determine the effectiveness of each one. Then somebody says well how about table salt? If I used enough of it could I use it to kill rats? (This is not a fictitious question since I know a fast food restaurant where rats set up camp in every possible piece of dirt they could find and it is alleged that some of the employees succeeded in killing them by using salt in various ways.) Then the government put up for bid a contract to test table salt for toxicity and lethality and guess who is the lowest bidder? You got it. The company that already test pesticides on rats. Why do you think there is such a great demand for illegal immigrants and why the government seems to be looking the other way? We have lots of situations where being the lowest bidder only works one way. That's no White upper class banker in that photo giving the guinea pig the dose. Its probably some guy from Cuba who found his way here through Mexico. Cubans use to be cannibals. Maybe such research has provided them with an alternate source of food. ...IMHO (Talk) 07:44, 1 July 2006 (UTC)

[edit] hydrogen sulfide, sulfur and ammonia in pond

Hi, I have a chemistry question. I have a whole pile of leaves in my small pond. I read somewhere that bacteria create hydrogen sulfide when they eat the leaves. But I remember reading about sulfur and ammonia can also be in the pond. Where does sulfur and ammonia come from? The bacteria eating the leaves? Or the leaves themselves?

The leaves are all black. And when I tried to remove the leaves, I saw some brown stuff swirling in the pond. It looked like dirt. I think the brown stuff came from the leaves. Any idea what it might be? Bacteria or little pieces of leaves? If anyone has any ideas, let me know. Thanks Sorry for all the questions, but I can't find a good answer. -Starionwolf 05:38, 1 July 2006 (UTC)

The amino acids cysteine and methionine contain sulfur, as do all polypeptides, proteins, and enzymes which contain these amino acids. This makes sulfur a necessary component of all living cells.
Some forms of bacteria use hydrogen sulfide (H2S) in the place of water as the electron donor in a primitive photosynthesis-like process.
So there is sulfur in the leaves and bacteria, as well as in the water to begin with. The sulfur for that hydrogen sulfide probably comes largely from the breakdown of the leaves. Ammonia is a molecule composed of hydrogen and nitrogen, and is made by bacteria that live on plant roots, so that probably comes from the leaves, and is just released by the breakdown of the leaves. Crazywolf 06:56, 1 July 2006 (UTC)
Thanks for the informative answer. I didn't know that the plants have sulfur and bacteria. I don't remember reading or studying anything about sulfur in plants. Thanks for taking the time to answer my question. I couldn't find a good answer online. I'll go read about ammonia and amino acids now. Bye --Starionwolf 03:19, 2 July 2006 (UTC)

[edit] Learning Java.

Well I just happened to visit Sun Microsystems wesbiste (maybe JAVA.COM, dont remember exactly), and they were offering their "compiler" or whatever it is called, which is used for writing java programs. So I wanted to know is it true that they are giving it for free? And secondly, what should I download if I want to learn Java. I have some ebooks, so I jsut want to try out those codes, like "hello world" programs and other simple things. So where should I write those codes? Thank You.

You will indeed need a compiler. There are many available ones, and I think most of them are free. The one I would recommend which is widely used is Eclipse, which can be downloaded here. Eclipse is a nice open source project that made a great java compiler.
Because of the peculiarities of the way the Java programming language works, you will also need the java runtime environment, which can be downloaded here, although you may already have it on your machine. You can download eclipse first, and it will tell you if you have it or not. If not, it can be found via the eclipse site here (pick the one appropriate for your machine).
As for learning java, there are gazillions of online and book references - not sure what to recommend here. Perhaps someone knows of a nice one? Once you get the hang of the basics, the best reference available is the official Java API from Sun - it's a listing and detailed description of all the routines in the Sun library. Have fun - it's a great language (and to the rest of you, for goodness sake let's be civilized and not start a C vs java war here) --Bmk 06:22, 1 July 2006 (UTC)
For tutorial I'd recommend Sun's own online tutorial, there is a "Tutorials" at java.sun.com. A "getting started" tutorial shows what to download, how to write the "hello world" program. For help there are the Java forums, drop in at "New To Java" with any questions you have. Weregerbil 08:17, 1 July 2006 (UTC)
As said above you will need both a compiler and a runtime. Both are available from several sources, some are free, some cost money. Writing Java codes is mostly a matter of writing a source code file, compiling it, and running it under the Java runtime. A source code file is simply a text file, you can write it in any text editor. Then you need to compile and run it. Example:
(you type in this Java code in a text file:)
public class Test {
  public static void main(String[] args) {
    System.out.println("Hello world!");
  }
}
javac Test.java
java Test
Hello world!

JIP | Talk 14:15, 1 July 2006 (UTC)

[edit] key steps to do any project

Like, i am given a project to find out the reasons for the "work in process"(WIP) of your department...i work in a packaging industry..we make packagings of paper and board like cartons of milk..etc..now i have to do this project quickly and accuratly...so i need some guidelines..that on wat steps i follow so that i can complete my project in least time and accuratly.

hi, i have given a science project and i need help from u people...i need some data about what are the basic steps to do any project..or simply how to do a project...kindly helpme out!

That's pretty hard to say generally about any project. If you're talking about an experiment in the sense of the scientific method, there's a decent article there. I'd say a good set of basic steps are, determine the goal of a project, determine the steps you will need to achieve the goal, then follow the steps. Perhaps you want something more specific? --Bmk 07:28, 1 July 2006 (UTC)
A project is a set of planned activities that aims to achieve certain goals or deliver certain products/results (and do so within a certain timeframe). It is not something that you do routinely or on a recurring basis. Formal project management is necessary for large or complex projects that: involve many people and/or resources, extend over a long period of time, have many complex dependencies, and/or involve many uncertainties. Because each project, by definition, has some unique aspects and is non-routine, its successful execution requires more than procedures and workflows that handle routine activites.
Project management involves analyzing the problem, breaking down the overall project into a set of tasks, identifying dependencies among different tasks and on external factors, estimating the time and resources needed for each task, scheduling each task (taking into account dependencies and resource availability), obtaining and assigning resources to each task, tracking the progress of each task, identifying and assessing any significant risks, contigency planning, and periodically reviewing progress and risks to re-adjust plans/schedules.
Complex projects often require tool support. Small projects many not require very formal project management, but planning and perodic reviews to stay on top of things are still important. See Project management.--72.78.101.61 14:06, 1 July 2006 (UTC)
A test environment is often needed to explore the viability of proposed alternative ideas, to see if they really do solve the problems without causing a bunch of new ones. I just learned that it is smart to spoof PRIVATE (e.g. social security numbers) and SENSITIVE (e.g. ethinicity) data in there, because development areas are usually not as secure as live ones. User:AlMac|(talk) 18:07, 12 July 2006 (UTC)
If you tell us what in general you are doing your project over, your question would be much easier to answer. Crazywolf
I always use the Feynman Problem-Solving Algothirm: 1) Identify the problem 2)Think really hard 3)Write down the answer. — The Mac Davis] ⌇☢ ญƛ. 15:23, 2 July 2006 (UTC)
Many projects need either an analyst or someone with such skills to
  • map out what are they now doing
  • does this bear any correlation to either ISO documentation of what they supposedly doing or
  • what the people in the department say that they are doing
Related to this are the quality of the inputs to the process, and what are the needs with respect to the outputs, and general record keeping.
To do any project effectively, a person ought to have some project management education, or else you could be headed for a fall. User:AlMac|(talk) 18:02, 12 July 2006 (UTC)

[edit] natural plutonium

What is the reason plutonium is not created naturally in the universe? ...IMHO (Talk) 07:53, 1 July 2006 (UTC)

It is created in supernova explosions (where almost everything heavier than iron is created). Some plutonium isotopes have such short half lifes that any deposits in Earth's crust have long since decayed into other substances; that's why we don't have plutonium mines. Check out the lead paragraph of plutonium for one isotope that is just stable enough to exist in tiny quantities. Every 80 million years there is half less of it. Weregerbil 08:02, 1 July 2006 (UTC)
So the answer is because there is no permanently stable form of it like there is for iron or lead? ...IMHO (Talk) 08:17, 1 July 2006 (UTC)
Plutonium gets created just like lead, but plutonium is radioactive and goes away given enough time. Atom by atom it splits into other elements. While lead is stable and sticks around. Occasionally a big star explodes in a supernova, creating a fresh batch of plutonium, which then starts decaying. The section "Supernovae as a source of heavy elements" in supernova describes that process, even specifically mentions plutonium. Weregerbil 09:08, 1 July 2006 (UTC)
It's not quite that simple. The various isotopes of uranium aren't stable either, but uranium-235 and particularly uranium-238 have extremely long half-lives. The radioactive decay of uranium (primarily U-235) results in various decay products, notably radium and radon. Any radium deposited in the gas cloud from supernovae disappeared billions of years ago; uranium decay is where all the stuff presently on Earth comes from. However, you're not going to get plutonium that way, as it is heavier than uranium.
About 2 billion years ago, some plutonium was naturally created on Earth; see natural nuclear fission reactor. --Robert Merkel 09:21, 1 July 2006 (UTC)
WOW! Thanks greatly for sharing this article. Its facinating to think that God had already tested a fission reactor long before he invented man. Wonder what else God has done that we don't know about? ...IMHO (Talk) 13:49, 1 July 2006 (UTC)
Well, he created something called religion to glorify himself, fooling people into thinking that he's perfect and all-powerful. He also created something called the Bible, to hide the true origin of Earth, life, and the univserse. --Bowlhover 14:57, 1 July 2006 (UTC)
Well at least you belive in Him even though you disagree with His methods. ...IMHO (Talk) 23:35, 1 July 2006 (UTC)
Well, no, I don't believe in him. --Bowlhover 18:30, 2 July 2006 (UTC)
Why would God need to "test" a fission reactor? Surely if you believe in a God which could create the universe and man you can believe that he doesn't need to run "experiments" to find out something as banal (and human-centric) as whether or not nuclear fission could be utilized to generate energy under controlled circumstances. Give your God a little more credit than that! --Fastfission 15:18, 1 July 2006 (UTC)
As I understand it the Bible says that God created the heavens and the Earth and at some point decided that it was good which leads to the question of whether or not he could have concluded that it was bad and hence did not know until after he created whether it might be either one. Maybe His creation of nuclear fission was for the same reason, i.e., to decide whether it was good or bad. ...IMHO (Talk) 23:35, 1 July 2006 (UTC)
Are you suggesting that, 2 billion years ago, God changed the laws of physics to make nuclear fission possible? If so, there's no evidence that the laws of physics ever changed. --Bowlhover 18:30, 2 July 2006 (UTC)
Surely God is as least as intelligent as Enrico Fermi, and could figure out without actual experimentation that something would or would not work. In any case, God, of the Judeo-Christian-Muslim variety, is all-knowing and presumably does not need to do anything in order to increase his own knowledge. While I understand the temptation to ascribe even the mundane to God, it strikes me as rather silly and inconsistent with the otherwise transcendent attributes usually ascribed to Him. --Fastfission 01:25, 3 July 2006 (UTC)
"Excuse me....excuse me.... what does God need with a starship?" -James T. Kirk --Bmk 17:54, 1 July 2006 (UTC)
Could we avoid another round of theist-atheist bickering, please? --Robert Merkel 04:04, 2 July 2006 (UTC)
This question has nothing to do with the existence or non-existence of God—all of those involved are actually advocating a more generously "theistic" reading of the situation—one which recognizes that God doesn't need to run science experiments. --Fastfission 01:25, 3 July 2006 (UTC)

I did not mean for this question to turn into a debate about God since the humanities desk is quite ready to handle debates like that but I will say now that the topic has been pressed that in terms of technology or science that God is the only entity by definition possessing the ability to reduce an infinite number of logical equations having an infinite number of variables and an infinite number of states to minimum form instantaneously. Further comments and discussion about God can be moved to the humanities desk. ...IMHO (Talk) 05:13, 3 July 2006 (UTC)

[edit] conservation

hi i require some fairly brief information on the general methods of conservation. not very detailed or specific to an area.

would you please furnish me with the different mothods of land, water , air and forest convervation.

i have tried to locate it on wikipedia but i'v allways found some " conservation ethic" which i havnt found to be quite what i wanted.

i would me very thankfull if you would heed to my requist as soon as your convinience allows.

thankin you, - Tulika

see sustainable agriculture for a start, though that article has neutrality issues. --Robert Merkel 09:21, 1 July 2006 (UTC)
Sorry, this isn't a Do-Your-Homework-For-You.com =D --mboverload@ 09:29, 1 July 2006 (UTC)

OK, here are "general methods of conservation, not detailed or specific":

  • To conserve land, don't build on it, plant in it, or dump toxic waste in it.
  • To conserve water, don't take it for irrigation and don't dump waste in it.
  • To conserve air, reduce smoke, vehicle exhaust and other chemical emissions. And breathe less.
  • To conserve forest, don't cut it down. Use corncobs and computers instead of toilet paper, books and newspapers.

Now go save your corner of the planet. alteripse 14:04, 1 July 2006 (UTC)

Conservation is disputed in being a good way of "saving the environment" I might add. — The Mac Davis] ⌇☢ ญƛ. 15:29, 2 July 2006 (UTC)
Would you care to support that statement? As I understand it, since conservation is shorthand for 'conserving the environment in a livable condition for the maximum variety of life', to say anyone considers it incompatible with 'saving' the environment seems to require some sources or cogent arguments. Skittle 16:08, 2 July 2006 (UTC)
The way I understand it, conservation is different from preservation. Conservation is an active and goal-directed process, while preservation seeks to eliminate all human activity. Personally I think conservation is generally more workable and realistic. --Ginkgo100 talk · contribs 21:12, 2 July 2006 (UTC)

[edit] Heart -Stoppers

Hello! I'm often amazed by the people who claim to arrest their heart-beat,temporarily,by some extraordinary means.I have seen a few people, on TV,performing this stunt(shown on some really reputed channels); even E.C.G records verified the cardiac-arrest.Now,my question is :

How can a man have CONTROL over his INVOLUNTARY MUSCLE ? Is it 'Mind

Over Matter'? Thanks, Pupunwiki 10:26, 1 July 2006 (UTC)

There could be no absolutely involuntary muscles. Heart-beat is somehow controlled by brain -- some unconscious part of it. May be, arresting heart-beat is possible by some technique, e.g. meditation or what, allowing control over subconsciousness? ellol 10:34, 1 July 2006 (UTC)
Not really. Read heart, cardiac pacemaker, autonomic nervous system, and artificial pacemaker. As for stopping the heart, I'm very skeptical. --Kjoonlee 12:58, 1 July 2006 (UTC)
It is quite easy to slow your heart rate by using a combination of meditation and breathing techniques (I used to regularly slow my heart beat to about 45-50 bpm before exams to relax myself), and I'm sure that if you trained yourself enough you could lower the rate to some quite impressively slow rates. But zero? I'm skeptical about that too. Grutness...wha? 13:36, 1 July 2006 (UTC)
Technically, the only way for your 'heart rate' to slow to zero or for your heart to 'stop' is for it to never beat again - if it doesn't beat for a while, then starts beating again, it's just slowed down a lot, not stopped. Since with no training at all it's possible for most people to slow their heartrate considerably as Grutness said, I wouldn't be surprised that with a lifetime of training a person could do something more impressive. --Bmk 17:57, 1 July 2006 (UTC)
Its simple really to stop your heart. Just hire a team of professional henchmen and get them beat the hell outta ya to within an inch of your life. BTW, before you do this have the paramedics stand by. If this is done perfectly your heart will stop for a while until the paramedis rush and revive you with a few high voltage electric shocks. And *wallah!!* you have a new World Record in Heart Stopping!! (Someone had a take a shot at it! ;-) Jayant,17 Years, India • contribs 20:43, 1 July 2006 (UTC)
To follow the style of the question: NO, You DO NOT have CONTROL over INVOLUNTARY MUSCLE. (OK, earphones off now...) A few aspects of the activity of involutary muscles may be modified by psychological techniques, but that is not the same as controlling the muscle contraction itself. To take the heart example: A person has no voluntary control of the cardiac muscle as such, only partial and indirect control of the rate of discharge of specialised pacemaker cells, which in turn determines the rate or cardiac activation, and very indirectly and unpredictably of the strength and rate of contraction via autonomic nervous system tone - in the latter case intrinsic Starling mechanisms would override any "voluntary" element. One cannot selectively or voluntarily control which part of the heart muscle contracts, how much of it contracts, in what sequence it contracts, how strongly it contracts, or when and how it relaxes. Once a cardiac cycle has started, the strength and rate of muscle contraction is automatic, dependent on factors not willfully determined. As far as I am able to determine, the cardiac cycle cannot be voluntarily contained to the point of death - unless you happen to suffer a heart attack or stroke due to low blood pressure or low blood flow, which would be unpredictable. I asked two anesthesiologists, they seem to feel that a vagal arrest of more than 6 seconds during surgery should be treated, though this figure from a book on cardiac surgery suggests that less than 4 minutes of circulatory arrest at 37°C usually does not cause brain damage. You cannot equate a learned and partial control of autonomic nervous activity with voluntary control of heart muscle, since it bears not even even a remote resemblance to voluntary skeletal muscle control. --Seejyb 10:41, 2 July 2006 (UTC)
Simple answer: It's a magic trick. and doesn't involve any 'real magic.'.
This is often used as a display of mind over matter' or 'psychic ability' or similar where the 'magician' will be able to change the strength of their pulse in different parts of their body, going so far as to have the pulse going in one hand, and completely stopped in other hand - and all this checked and verified by real doctors or nurses taking the pulse (who are invariably amazed)
***SPOILER WARNING***
***SPOILER WARNING***
***SPOILER WARNING***
This trick is done very simply by concealing a rubber ball or rolled up sock in the armpit of each arm. By squeezing it harder or softer with the armpit it will press against an artery in your arm, causing the blood flow, and therefore the pulse, to weaken or strengthen. It's incredibly simple, basically self working, and any child could do it, yet it has been used to wow audiences by some top 'psychics'. Just goes to show, often the simplest things are the most effective! --Noodhoog 15:40, 6 July 2006 (UTC)
Me again. This is a bit off topic, but I just thought I'd add a quick justification for the reveal above. Normally I wouldn't dream of revealing the method behind a magic trick, but this one is a particular favourite of con-artists, frauds, and charlatans. That is, those who claim to have actual magical/pychic powers and abuse their audiences by pretending to contact dead relatives, hawking their merchandise, and so on. I have absolutely no problem with (and indeed great respect for) the highly skilled magicians who make no fradulent claims to supernatural ability, and openly admit they are entertainers who use lots of clever techniques to produce the effects they do. --Noodhoog 15:50, 6 July 2006 (UTC)
Thanks Noodhoog...I studied and found in a book,(written by Prabir Ghosh) exactly the same trick,mentioned by you.I will like to add the name of the arteries you mentioned.The one under the armpit is the axillary artery , while , the one in the wrist (from where pulse is recorded) is the radial artery... I believe the information I provided is true... If however, anyone finds any mistake, I request him/her to rectify it.--Pupunwiki 08:56, 18 August 2006 (UTC)

[edit] Automatic WMA to MP3 Converter?

I have a large mix of .wma files and .mp3 files on my computer, but don't know which are which without going through a huge caffufle. Is there are program that will search a folder or drive that I tell it to, converting wmas to mp3s as it goes? --Username132 (talk) 12:07, 1 July 2006 (UTC)

Why is it hard to tell which is which? Can't you tell just by looking in Windows Explorer? Notinasnaid 12:32, 1 July 2006 (UTC)
It's hard because we're talking about 50.8 GB of music and I have a life (albeit not much of one) outside of audio conversion! --Username132 (talk) 16:43, 2 July 2006 (UTC)
Sort them By Type in Windows Explorer, or use the Windows Search function to find all WMA files. (For a converter, I'd search for convert wma mp3). –Mysid(t) 12:39, 1 July 2006 (UTC)
Or use a search program, like Windows search, and type for your search term "*.wma" to find the wma files or "*.mp3" to find the mp3 files.--Bmk 18:10, 1 July 2006 (UTC)
Transcoding of lossy audio is evil. Avoid it at all costs! I'm sure there's a better solution to your problem than transcoding. Why do you want to do it? --Kjoonlee 12:47, 1 July 2006 (UTC)
Thanks. I wont bother now... --Username132 (talk) 16:43, 2 July 2006 (UTC)
At least the question wasn't how to convert WMA to Ogg Vorbis. Then I'd be worried that someone would try to upload those crappy files to Wikipedia. —Keenan Pepper 18:43, 1 July 2006 (UTC)
It's suprisingly hard to find free audio converters on Google. You have to have the social equivalent of "knowing someone" to find a good one. Try this on for size: http://winlame.sourceforge.net/ --Russoc4 15:09, 8 July 2006 (UTC)

[edit] Muay Thai shin conditioning

On Muay Thai's shin conditioning method (or how to kill your nerves):

long ago before the availability of pads and bags, Thai boxers kicked banana trees. The texture of a banana tree is rubbery and is softer than a person's shin.

I am not going to train myself to be the next Tony Jaa. My only question is: How long can a banana tree survive if people kick it every day ... -- Toytoy 13:13, 1 July 2006 (UTC)

Two days, eight hours, and seven minutes.

[edit] Dreaming in colors

What's with dreaming in colors? A lot of people seem to take for granted, at least as I can see in the media, that the "normal" way of dreaming is dreaming in black and white... I find that quite strange, as I have always dreamt in color. What's your experience? Is it actually that normal dreaming in black and white? GTubio 13:36, 1 July 2006 (UTC)

Isn't it portrayed as black and white or with wavy edges in media, to make it obvious that it is a dream scene. Philc TECI 14:02, 1 July 2006 (UTC)
I've always dreamt in colour. Though, the most unusual thing about my dreams is that I can not remember what colours the people and things were in my dream, even if I can remember the entire dream (which is very rare!), how much ever I wack my brain, I cant remember the specific colours of things in my dreams. Most unusual......or is it? Jayant,17 Years, India • contribs 20:33, 1 July 2006 (UTC)
I think its normal, I think its almost impossible to recall anything in your dreams that you didnt make specific note of while you were having them, so you can remember the events, storyline, things that effected and people you interacted with, as it was brought to your attention. Or atleast thats what I find, though I think it may be completely different for some people, particlarly people with things like photographic memory. Philc TECI 21:14, 1 July 2006 (UTC)
There was a recent discussion on physicsforums to if blind people can dream in color. [2] — The Mac Davis] ⌇☢ ญƛ. 15:32, 2 July 2006 (UTC)
And how would you know a dream was in colour, unless you specifically dream about a colour detail--as it happeded, I had a dream once where I noticed the colour of something. But we generally don't specifically dream about colour. I have a feeling that even the notion of black & white dreaming was meaningless until the invention of photography filled the world with monochrome images. I have a related question: Has anyone seen any reference, dating from before the invention of photography, discussing whether we dream in black and white?
My mother said that after we got a colour tv in the sixties, she dreamt in colour for the first time. I suppose it's just that she was aware of the colours in her dreams for the first time.
Human eyes have separate receptors for colour and light-intensity (ie black and white). So the notion of black and white was not introduced by photography. DirkvdM 09:45, 3 July 2006 (UTC)

[edit] methanol added in a tank of gas in car - Ratio

I need a ratio thats safe?

How does methanol work in a car.

If your car isn't designed for methanol, then don't put methanol in it. You don't say what you're trying to achieve, anyway.

If aluminum is incompatible with methanol what does that mean.

From Methanol:
One of the drawbacks of methanol as a fuel is its corrosivity to some metals, including aluminium. Methanol, although only a weak acid, attacks the oxide coating that normally protects the aluminium from corrosion:
6CH3OH + 2Al → 2Al3+ + 6CH3O− + 3H2
The resulting methoxide salts are soluble in methanol, so the corrosion continues until the metal is eaten away.
In other words, methanol eats away aluminum until there's nothing left.

How does octane levels work

See Octane rating. —Keenan Pepper 18:32, 1 July 2006 (UTC)
Maybe you are refering to ethanol? See E85 and flexible-fuel vehicle as well. --Russoc4 15:26, 8 July 2006 (UTC)

[edit] What's in this cardboard box?

I found this cardboard box (full size image) near the entrance to a park. I think the person who put it there wanted people to believe it's a bomb. (Of course, if you take a closer look, you'll see that it can't be a bomb--there's no room for the explosives and no batteries.)

Anyone know what it actually is? I think it may be a radio (with the orange, rectangular object at the bottom right of the plastic casing being its antenna). --Bowlhover 14:20, 1 July 2006 (UTC)

My guess is a radio too, or maybe just a speaker (though it has a lot of electronics to be just a speaker). - Dammit 14:39, 1 July 2006 (UTC)
Yeah, it looks like a radio built to look like one of those really old tombstone-shaped radios. --Bmk 18:00, 1 July 2006 (UTC)
If they wanted it to look like a bomb, they did a pretty poor job. Why would a bomb have a speaker? And what if nobody bothered to plug in the cord? --Ginkgo100 talk · contribs 20:47, 1 July 2006 (UTC)
I agree. I think they didn't want to fool the police. They just wanted to scare people who freak out upon seeing wires in a cardboard box. --Bowlhover 17:37, 2 July 2006 (UTC)
I think it's just garbage being analyzed by someone with an over-active imagination. —Bradley 07:05, 3 July 2006 (UTC)
How much imagination is needed to identify a radio as a radio, like I did? None. I was just curious. I never said the radio is a bomb, nor that it bears the slightest resemblance to a bomb. I was just curious as to why someone would disassemble a radio, put it in a box, and put the box beside a path that leads to a park. Of course I know it's just garbage, except that it wasn't put in (or anywhere near) a garbage can. --Bowlhover 19:42, 3 July 2006 (UTC)

The antenna of this radio is the ferrite rod - wound round with the various coils that you can see. It is most likely a medium wave receiver.--G N Frykman 20:54, 1 July 2006 (UTC)

The world is going nuts. People now see bombs in harmless piles of rubbish. Well, one could call the abundance of waste an ecological time bomb, but that's something different. :) DirkvdM 09:49, 3 July 2006 (UTC)

[edit] Want to know about scientific experiments proving anything related to supernatural.

Any one?


No. In such a case this "supernatural" will just turn out to be natural and real. (It happened many times in the history of science, e.g. "stones falling from the sky" were considered ridiculous by French Academy of Sciences one time.) This raises the question, whether supernatural "phenomena" should at all be investigated by means of science — perfectly shown in "With morning comes Mistfall" story by George R.R. Martin.
ellol 17:57, 1 July 2006 (UTC)

I'd have to say that if a scientific experiment demonstrates the existence of a phenomenon, then it is not supernatural - it is natural. The first sentence of our supernatural article gives a good definition. I guess there are plenty of instances where phenomena which were attributed to supernatural causes have been explained via the scientific method. For instance lightning used to be God's weapon of choice, now it's known to be caused by electric potential differences. St. Elmo's fire is another neat one (which is actually related to lighning) that science has explained. There are lots. --Bmk 18:02, 1 July 2006 (UTC)
Some physics experiments appeared to violate the very reliable Newtonian laws. The result was the development of quantum mechanics, not a declaration that the experiments showed something supernatural. The best science can say about the supernatural is there is currently no known scientific explanation. I believe in certain spiritual things including miracles, but science is not designed to investigate them. That said, you could visit this site, which explains the Catholic process of verifying miracles for potential saints, as well as the Dec. 8 entry at this site, which is quite skeptical of miracles altogether. --Ginkgo100 talk · contribs 02:47, 3 July 2006 (UTC)
If you had a person who could, with no apparent external apparatus, at will violate various scientific laws which are known to be fairly reliable—conservation of energy and mass, for example—it would be a semi-persuasive argument for the possibility of a supernatural. If under intense and open scrutiny no explanation for these controlled violations could be discovered, then perhaps one could conclude that science couldn't explain it, and that it may lie outside of the realm of "natural" explanation. There have certainly been no phenomena of that sort subjected to such scrutiny, though—almost all claims to the supernatural today are vague, anecdotal, and specifically reject being looked at under controlled circumstances, an almost sure sign of them being snake oil of one sort of another. --Fastfission 19:41, 1 July 2006 (UTC)

Well, as implied above supernatural usually implies soemthing beyond or in contradiction of scienice. Perhaps a more apt word would be "paranormal", which usually describes unexplained phenomena from U.F.O.s to ghosts. --Kronos-X 14:04, 1 July 2006 (PTC)

As they said above, once science has confirmed and studied it, it isn't considered "supernatural", no matter how weird it is. There have, however, been a number of things that seemed "supernatural", or even nonexistent, at one time that have since been studied extensively, like the examples above. Some things I'm still waiting for: telepathy, telekinesis, lycanthropy, immortality. Nothing I know of has confirmed the possibility of these things, but I'm optimistic. Black Carrot 15:49, 3 July 2006 (UTC)
BTW, you may be interested in the work of James Randi. Black Carrot 15:52, 3 July 2006 (UTC)

For astrology/occult-type things (in the sense of disproving them), see Forer effect and a few of the links on that page.

Being a Christian (myself), I think you might find it difficult to find studies (i.e., in journals) about miracles, mostly because one doesn't know they are going to happen before the fact. There are cases, though, where a certain medical condition is recorded by a doctor over a period of time, the person gets healed, then tested again, and so a healing can be shown retrospectively. But you can't really look for miracles under experimental conditions. BenC7 02:47, 5 July 2006 (UTC)

I think many scientists have a really tough time coming to grips with the concept of the supernatural. Their basic position is that everything that can be observed by humans must, ultimately, have a rational explanation. Even if we can't quite explain it now, one day we will be able to, it's only a question of time. What seems to be outside their thinking is the possibility of some event that is inherently outside the laws of physics - not only the laws as we currently understand them but beyond physics entirely, and for all time. The concept that an observed phenomenon might never be explained by science is anathema. Many other scientists are deeply religious; even many non-religious ones believe the only possible explanation for the universe is a Supreme Being who created it out of absolutely nothing. It's a logical certainty that contains a scientific impossibility. No wonder it's been driving thinkers nuts forever, and will always do so. JackofOz 03:36, 5 July 2006 (UTC)

[edit] Wild and crazy idea...

LD50 is an article about toxicology that refers to the amount of a substance that will kill 50% of the population. The idea is that knowing the amount of a substance having a 50/50 change of death is a good guide to the lethality of the substance. How about instead of determining the LD50 dose a lab were to determine the dosage curve from 0 to 100 percent, which would of course include the LD50 amount but also the amounts for minimum and maximum lethality as well as the theoretical and emperical amounts that lie in between? Or am I missing something here? Can these other amounts already be computed from the LD50 amount? ...IMHO (Talk) 23:23, 1 July 2006 (UTC)

Yes, you again, missed something. Either you missed to read the whole article that you just quoted, i.e. LD50, or you did not understand it. 130.94.134.166 23:34, 1 July 2006 (UTC)
My point is that even though there are a wide variety of other measurements there appears to be no single method of including all in one presentation or display such as a "curve of death" might provide. Likewise there seems to be no way of also including the various routes a toxin may take to do the job as well as the time and many other relevant factors. Not that the laymen needs to have a comprehensive chart that give a good overall idea of how dangereous a substance is but then some laymen do stuff like make laws and tot stuff for people and would like to have a comprehensive idea whithout being required to first attain a Phd. But then now that I think about it I'd rather have a Phd than a comprehensive chart. ...IMHO (Talk) 23:50, 1 July 2006 (UTC)
Why the bloody hell do you feel you have the right delete my posts, its the reference desk, not your user page you ass. Philc TECI 01:42, 2 July 2006 (UTC)
What in the world are you talking about? Nobody's deleted anything here; calm down. Melchoir 01:49, 2 July 2006 (UTC)
And my answer is, there probably is, but then you have to administer multiple tests to get enough data to plot an entire graph (rather than one data point). And its a graph its simple, theres not going to be an article on it, or any papers for you to look at, because its a graph. Where-as LD50 needs explanation, as it is not self-explanitory. My point is, maybe your curve of death is used, what proof do you have that it is not, what proof do you need that it isn't. Philc TECI 01:47, 2 July 2006 (UTC)
I guess if you have a particularly simple mathematical model for how a substance kills, then it might be possible to calculate the entire curve from one measurement. But in general, it isn't possible, and I'm sure labs take all kinds of data points that aren't described in a Wikipedia article. Melchoir 00:07, 2 July 2006 (UTC)

Also User Philic please consider what happens to the LD50 tests that result in a 27/75 life to death ratio instead of a 50/50 life and death ratio that are simply thrown away becasue they are not 50/50 whereas a LDzero to LD100 percent curve would have a place to put all of that unused data instead of throwing it away (BTW I am afraid to ask what the heck you are talking about in regard to anyone deleting your messages. Maybe if you are going have a little tody before bedtime it would be best to stay off the wiki.) ...IMHO (Talk) 02:17, 2 July 2006 (UTC)

Generating the entire toxicity-response curve requires far more data than finding the LD50, which means that many more animals must be killed. Also, for many applications, it is more useful to have a few key statistics rather than the entire set of data. Nevertheless, toxicity-response curves are sometimes used. For an example of what one looks like see page six of this PDF, for instance. — Knowledge Seeker দ 06:44, 2 July 2006 (UTC)
That was the reason for my question above. If there are no deviations in the curvature then say only three measures (LD1, LD50 and LD99) would seem to suffice but since there are other factors besides dose or amount like method of intake, etc. it would seem now that a complete database is needed for each toxin so that one can plug in values like weight and dose and type of intake, etc., i.e., all of the relative factors that effect the toxicity for a particular item instead of several values, curves or charts. ...IMHO (Talk) 15:07, 2 July 2006 (UTC)
  • An LD50 value is the dosage of a chemical that kills 50% of the test population of animals. The idea is that scientists can use these values to calculate a lethal dose for humans based on body mass without actually killing any people in the process. - Mgm|(talk) 08:18, 3 July 2006 (UTC)

[edit] Is rolling tobacco healthier than regular cigarettes?

This seems to be an oft-quoted 'fact'. Anyone know if it's true that smoking rolling tobacco causes less damage to the lungs than pack cigarettes? I've heard it mentioned that it's better for you because it contains less additives. No propaganda please. --84.68.140.72 23:55, 1 July 2006 (UTC)

  • Well, it's certainly the case that a rolling tobacco with fewer or no additives (and it's not the case that all rolling tobacco fits that description) won't cause harm from the additives that aren't there. On the other hand, are the additives more or less harmful than the tobacco that the additives are displacing? And what's the degree of difference? Is it, like, pack cigarets have a 40% chance of giving you cancer and rolling tobacco has 39%? Or is it more like .01% and .095%? But this is kinda like asking how much a yacht costs (if you have to ask, you can't afford it). --jpgordon∇∆∇∆ 00:02, 2 July 2006 (UTC)
I do know that if I smoke 20 regular cigarettes over the course of an evening, I will wake up with a sore throat, nasty taste in my mouth and a cough the next morning. If I smoke 20 rollups, I feel fine. The only reason I can think of is that there is something in the packet cigarettes that doesn't agree with me. --84.68.140.72 00:08, 2 July 2006 (UTC)
Certainly. And some cigs are WAY worse than others in that regard. But that doesn't mean the rollups are healthier -- it could also just mean that the toxic effects don't show as quickly. It could be argued that pack cigs are statistically better for you, as they are more noxious and more likely to make you quit sooner. --jpgordon∇∆∇∆ 03:06, 2 July 2006 (UTC)
Also, one cigarette is not unhealthy. Its the many you smoke that has been known to be bad for your lungs. — The Mac Davis] ⌇☢ ญƛ. 15:39, 2 July 2006 (UTC)
I always thought even one cigarette is unhealthy. Even the tobacco companies tell us "there's no such thing as a safe cigarette." I suppose you're unlikely to suffer any serious or long-term effects from a single cigarette, but that doesn't necessarily make it "not unhealthy." --Ginkgo100 talk · contribs 21:17, 2 July 2006 (UTC)
Also, note that hand-rolled cigarettes are unlikely to include any sort of filter to remove some of the nasties (not that a filter stops a lot of nasties, but some of them). Unless you regularly buy filters to add to your cigarettes? And Mac, I'd say one cigarette is bad for you (you're inhaling smoke for one thing, plus the other stuff), it's just unlikely to kill you by itself. Skittle 15:56, 2 July 2006 (UTC)
Well, everything is relative. The exhaust fumes of a car passing by won't be very unhealthy. Living next to a busy road is. That's a bit obvious, isn't it? DirkvdM 10:15, 3 July 2006 (UTC)

[edit] bah

I just loaded a page with advertising by google, and for the first time ever I get a google video based popup add, what the hell? I think they're getting a little carried away with these things--71.249.29.10 00:05, 2 July 2006 (UTC)

Get Firefox and add the extension Adblock. Easily block any and all Google ads. Now, someone say there's some way to trick IE/Opera/Safari/MyWickedCoolWebBrowser into blocking Google ads too. --Kainaw (talk) 00:45, 2 July 2006 (UTC)
Hmmm... Donate lots of mone to Google so they don't need any more ads (which brings up: "They're very greedy, all that money and they still advertise.") and then continue to use the same browser only without ads. :-) Iolakana|T 15:19, 2 July 2006 (UTC)
Sounds fishy to me. --mboverload@ 22:29, 2 July 2006 (UTC)
Donate to Google? They are not non-profit—they are trying to make money, as much as possible! They'd take your money, thank you, and happily continue business as usual. It isn't greed, it's how you run a business. --Fastfission
Their revenue is $7.14 Billion. If I gave you that, would you ever work again?! :) Iolakana|T 15:21, 4 July 2006 (UTC)

that wasn't from Google! it was from a third party just embedding a google video. Scumbags. Google doesn't do what you state, and they have probably already banned the advertisers who misrepresented their popup as Google's.

Retrieved from "http://en.wikipedia.org../../../r/e/f/Wikipedia%7EReference_desk_archive_Science_2006_July_1_4f08.html"