Wikipedia:Reference desk/Archives/Science/2006 July 11

Electrochemistry

Would it be possible/useful to stick a strip of magnesium to an unpainted part of a regular car body to protect it from rusting (i.e., as a sacrificial anode)? BenC7 01:13, 11 July 2006 (UTC)

According to the rust article, this would only work if you put the magnesium in an area where it was in contact with both the steel that was being corroded and the water that was doing to corroding. The cathodic protection article implies that this would be a bit complicated, though, as you would have to make sure that the electrochemical potential of the sacrificial anodes is sufficient to eleminate the electrochemical potential of the steel body of the car when they interact with water. Galvanizing the steel or covering it with paint is probably easier. Crazywolf 02:19, 11 July 2006 (UTC)

Right - any spots where water is touching the car, but is not connected by water to the magnesium is not affected by the presence of the magnesium. --Bmk 02:57, 11 July 2006 (UTC)

I understand what Crazywolf is saying about the potential differences. But Bmk, the water is obviously the water in the atmosphere. This would mean that you can only use a sacrificial anode where it is partially immersed in water and not, say, on a steel beam sitting in your backyard. Are you sure about this? I have a feeling it is just due to the potential difference, as you can purchase electronic devices for your car that provide it with an overall negative electric charge, which is what the sacrificial anode does. And the device is not in contact with the atmosphere. (I hope I am saying that clearly enough.) BenC7 10:17, 11 July 2006 (UTC)

Good point. However, the metal gets "protection" because a potential-diff is placed across a molecular thin film between the layer of water and the metal. This e-field is so high that it halts the electrochemical reactions in that layer. The e-field in that has a staggeringly huge value, like volts per picometer. To create a similarly high surface-field in humid air with no complete circuit, the car would have to be charged to unattainably high voltage with respect to ground (WAY higher than teravolts.)--Wjbeaty 16:10, 11 July 2006 (UTC)

The idea I have gathered is that the magnesium has to be in contact with the water in order to have the electrochemical reactions that result in it's giving the steel the negative charge that protects it. It is still probably possible to protect the car from the rusting properties of humid air, if not that of rain, with enough sacrificial anodes placed on the underside of the body and spaced properly. It might be worth exploring, especially for valuable older cars that have lost their rust protection, but would be difficult to rustproof again through galvanizing. Crazywolf 20:32, 11 July 2006 (UTC)

• Didn't they use zink on ships. Off the top of my head, that's a lot cheaper than magnesium. - Mgm|^(talk) 08:15, 11 July 2006 (UTC)

Yeah, there are a few metals that you can use for a sacrificial anode. I had no particular reason for picking magnesium. I just saw this thing on telly where a guy (chemist) used a pencil sharpener, which he said was mostly made of magnesium, to protect a long, thin wire that was suspended on floats out at sea. I wondered what the difference was between that wire and a car -- otherwise I'm sure we would all have sacrificial anodes on our car that we would replace every now and then. So I was basically looking for the reason why we don't do that. BenC7 10:17, 11 July 2006 (UTC)

Diet problem

Does anyone here know the real solution of the diet problem, how to meet all your nutritional needs and spend as little as possible? Since supplements such as Ensure use added vitamins and minerals as sources rather than whole foods, it appears that the micronutrients must be very cheap. We need water (essentially free), calories, ess. amino acids, ess. fatty acids, and micronutrients. The cheapest source of calories is probably something like unprocessed soybean oil, which also meets fatty acid needs, at around 30¢ per 2000 kcal. Protein probably costs a minimum of around 20¢ for daily requirement (if from soybeans bought in bulk - my calculation). So 50¢ per day of macronutrients, what for micronutrients? -User: Nightvid

not that simple. for one, soy protein (along with most plant protein) doesn't have the right amino acid composition to be a complete dietary protein source, to do the same thing you'd need to substitute something derived from animals (BSA or whey protein?) or maybe fungi (somesort of mushroom?). fungi would also help with the micronutrients too. Xcomradex 03:33, 11 July 2006 (UTC)

I'm thinking plankton. —Keenan Pepper 03:41, 11 July 2006 (UTC)

Mmmm...no need to resort to animals for protein or anything else. There are millions of vegetarians to attest to that; they're all healthier than everyone else, anyways. I'd say the cheapest and healthiest way to solve "the diet problem" is to eat real food. Where do you think the supplement industry people get most of their vitamins and whatnot? Mostly extracts from plants or animals - just with more processing. Much better to go straight to the source and skip the inevitable denaturing and factory-grade chemicals.

Eat whole grains, lots of vegetables, especially nice dark green ones, and you'll be fine. Maybe a B-12 pill once in a while (or just don't wash your vegetables; B-12 is produced in soil bacteria. The reason meat eaters don't need extra B-12 is because they eat animals who spend their time licking each others' crap). If you have to, have some meat on holidays. Some periodic fish intake isn't unhealthy, but watch out for that nasty mercury and lead that tends to build up - yum!

Being vegetarian is very cheap; just take a look at the menu at a restaurant once in a while. The meat options are often a good 150% more expensive than the vegetarian ones. Meat eaters are paying for 10 or 20 times more vegetables than vegetarians, in the form of animal feed. It's not a new, or radical idea. Just people don't like to give up their greasy burgers and slabs of steak - heart disease apparently is yummy, after all.

As a side note, there have been studies (i'm too lazy to look up links) about how long people can survive on potatoes, olive oil, and water - a long time. Potatoes are a very complete food - lots of stuff packed in there, especially if you eat the skin (the olive oil was for extra calories). --Bmk 04:15, 11 July 2006 (UTC)

I felt bad saying all that without any backup, so here's a link to the Physician's Committee for Responsible Medicine. And here are their very illuminating FAQs about vegetarianism. Just to quote from the FAQ "How can I get enough protein?", entitled "The protein myth". "A variety of grains, legumes, and vegetables can also provide all of the essential amino acids our bodies require." Also, "With the traditional Western diet, the average American consumes about double the protein her or his body needs." Keep reading downward - a lot of good oldfashioned scientific myth debunking on that page. --Bmk 04:32, 11 July 2006 (UTC)

key word: variety of legumes, grains etc. a single vegetable source isn't enough, where as meat is a one-stop shop. not that i'm knocking vegeterianism, i'm just pointing out if you want a single source it has to be meat, or meat-like (fungi, or plankton... good call keenan). no doubt it will still be cheaper to buy multiple vegetables than one meat. Xcomradex 04:52, 11 July 2006 (UTC)

Bmk, vegetarians healthier than everyone else? I once attended a rainbow gathering (for about a month), where all food was vegetarian. And I saw some people there who didn't look too healthy, one even with a malnutrition-potbelly. The effect it had on me was that I got a bladder infection because of all the sugar in the fruit. It took me over a year to get rid of it. Maybe you can live a healthy vegetarian life if you're very careful about your diet (as a vegetarian you have to be), but your statement is definitely not true. DirkvdM 06:32, 11 July 2006 (UTC)

• Yeah, those supplement manufacturers make pretty good profits. Go to the source and you're already off much cheaper. Supplements and vitamins are not a good replacement for real food (vegetarian or not). - Mgm|^(talk) 08:12, 11 July 2006 (UTC)

I think you all are missing the point. The question asked how to spend as little as possible, not how to eat healthy foods and lose weight. It's a much more interesting question than the ubiquitous question that you are all answering. Right. To throw in my answer, I would add that there are a number of AA supplements out there that you could easlily use. The ones that bodybuilders use are pretty expensive, but I have also fun into a soy-sauce-looking bottle in a chinese food store simply called "AMINO ACID SAUCE" (no joke!) that was pretty cheap and contained all of the essential AAs. The full entourage of vitamins and minerals do appear to be available in knock-off brand supplements.

I have looked up the AA composition, and soy protein does have ALL the essential AA's in it-it's 60% bioavailable based on the limiting AA, so it is still a very cheap way of getting all your AA's. What I'm really trying to figure out is the micronutrients, since the macronutrients are relatively simple. -User: Nightvid

A few people mentioned that plankton and fungi are "meat-like". How are they related to meat? I'd also like to say without any ill will that DirkvdM's anecdote about his personal bladder problems do not strike me as a convincing argument about the benefits of a vegetarian diet. More convincing would be a study, like the Oxford Vegetarian Study. Apologies for sidetracking the question --Bmk 15:42, 11 July 2006 (UTC)

Plankton is an animal source (see Antarctic krill) and like all animal protein sources, it would be complete protein. I don't know that fungi would be "meat-like" except possibly culinarily speaking. As for the healthiness of a vegetarian diet, that really depends on the specifics of each diet. There are vegetarians who eat terrible diets. I know one who eats virtually nothing but white bread, cheese, and sweets, and I'm sure it will catch up with her soon. (Obviously she is not vegan.) On the other hand, I as a meat eater have what I would consider a very good diet -- lots of fresh fruits and vegetables and whole grains balancing the amount of meat I eat, and little refined sugar. However, the typical vegetarian probably eats a more nutritious diet, if they pay attention to their protein needs, than the typical non-veg, since in search of variety they usually eat a huge range of different foods. --Ginkgo100 ^{talk · contribs} 19:18, 11 July 2006 (UTC)

I absolutely agree - simply being vegetarian isn't enough - variety is another good key --Bmk 20:27, 11 July 2006 (UTC)

Bmk: fungi - "Indeed, fungi are now thought to be more closely related to animals than to plants...". this is true at a biochemical level too. and of course, quorn. Xcomradex 22:08, 11 July 2006 (UTC)

Mooon craters.

Is the moon still being hit by meteorites or has this activity now ceased? If these 'strikes" still take place have astronomers ever witnessed such an event and how frequently do they happen?

Sabaco 04:25, 11 July 2006 (UTC)

http://en.wikipedia.org/wiki/Moon#Meteor_impact_on_the_Moon

fyi, thirty seconds searching wikipedia would have saved you thirty minutes waiting for an answer

Xcomradex 04:57, 11 July 2006 (UTC)

Moon. --Proficient 23:03, 12 July 2006 (UTC)

leitz edinger projection apparatus.

Does anyone have information on a leitz edinger projection apparatus.

Bold and CAPS text make you look stupid, and I'm sure you don't want that so I fixed your question for you. I felt lucky with Google and I found quite a bit of information. Unless, of course, you are Bruce Allen.  freshofftheufoΓΛĿЌ  05:21, 11 July 2006 (UTC)Thanks for your comments butI have all the information from the internet, I was hoping someone had some personnal knowledge.

It helps to be a little bit more specific when you ask your question. Something like "I've done some research on the internet about Leitz Edinger Projection Apparati, but I still don't know this thing about it and does anyone know?" might get you a better response.  freshofftheufoΓΛĿЌ  03:33, 12 July 2006 (UTC)

Direction of current in the coil

Imagine a bar magnet moving towards a coil, with north pole nearer to the coil. Now there will be a current induced in the coil (anticlockwise, looking at the coil from the magnet's point of view). When the magnet is moved, even the south pole moves towards the coil and hence the south pole too induces some current in the coil (albeit of a lesser magnitude, due to the larger distance from the coil). Now the question is, in which direction does the SP induce the current? In other words, will the currents induced by the NP and SP aid or oppose each other?

One of the arguments is that the SP moving towards the coil induces current in a different direction than the NP moving towards the coil (like the case where a bar magnet moving towards the coil with the SP nearer to the coil would induce the current in the clockwise direction). But the other argument is that the direction of current will be the same because the direction of the line of magnetic flux is the same.

Which argument is right? --Wikicheng 05:54, 11 July 2006 (UTC)

You should describe more or provide a diagram of the positions of the coil and magnet, because the answer depends on the arrangement. Faraday's law of induction says that the induced current along a closed path is determined solely by the time rate of change of the magnetic flux through it. So what you must ask yourself is, what effect does the movement of each pole have on the flux through the loop? -User: Nightvid

First of all, I think you should read a little bit about permanent magnets at magnet (not all of it - it's rather in depth). You can't treat the "north pole" and "south pole" of the magnet as "sources" of the magnetic field - they aren't. If you cut the magnet in half, you would have two north poles and two south poles. The key is the permanent dipole magnetic field that the magnet generates. You should also read dipole, and look at the illustration to help you visualize. Now, the key here is Maxwell's equations, specifically Faraday's law of induction (this is also a very useful article to read).

Faraday's law states that the closed line integral of the electric field (essentially the induced voltage around the coil) is equal to the negative change in magnetic flux. The magnetic flux is the magnetic field integrated over a surface bounded by the coil. So, if you imagine the magnetic field lines emerging from the magnet from the north end, you can see from the illustration in the dipole article that the field is stronger as you approach the magnet. So, the magnetic flux through the coil increases as the magnet approaches, meaning the voltage is induced in the negative direction, which, if you consider the north pole to be pointing "up", is counterclockwise. Hope that helps! --Bmk 13:30, 11 July 2006 (UTC)

Now that I think about the issue again, any infinite plane has magnetic flux of zero (Gauss's Law-Absence of magnetic monopoles), so what's actually happening is the magnetic field inside the magnet must be going backwards! Because the field is created by the angular momentum of the electrons, it is essentially equivalent to a giant number of atomic "solenoids", and remember that the field inside a solenoid is "backwards". Since this reverse field must balance the entire external field out to infinity, the plane integral through the loop of wire, being finite, must be "backwards" itself. -User: Nightvid

The n-pole induces a current, and the s-pole induces an OPPOSITE current. Why? Well, suppose we bring the n and s poles very close together (shorter magnet) and then thrust this through the coil. If the induced currents were in fact opposites, then the induction effect would be weaker. And the induction effect would go to zero if the n and s poles were superposed (in a zero-length magnet.) However, if the n and s poles induced the same polarity of current, then a zero-length magnet would create DOUBLE current, not zero current.--Wjbeaty 16:00, 11 July 2006 (UTC)

Yes. This (Wjbeaty's answer) was exactly what I was looking for. Does this mean that if I need to generate electricity by moving a bar magnet in and out of a coil, then it is better to use a longer magnet? (Because if I use a shorter magnet, then the currents generated by the opposite poles tend to nullify each other. But in case of a long magnet, the effect of the pole farther from the coil can be ignored?)--Wikicheng 04:44, 12 July 2006 (UTC)

please help me answer the following

good day. i'm doing a research on bacteria. i can not find or have a hard time finding out the following: 1. how to identify the methods in examining unstained living bacteria and its advantages. 2. discuss the methods of examining stained bacteria in a fixed preparation; in simple, differential and in special staining. 3. how to collect specimen on: blood, feces, CSF, upper respiratory tract, lower respiratory tract, in urine and in the genital tract.

thank you.±--Larry jr 07:38, 11 July 2006 (UTC)

• Erm, Larry. I removed some signatures. One of them is enough. About the question:

1. I don't remember investigating living bacteria myself, but the advantages should be clear. There's things you can't investigate in death organisms.
2. I'm not going to do your work for you. Every text book about microbiology will explain the methods these stainings use and how to examine them (usually with a microscope. We have a nice little article about differential staining.
3. Again this is something a book you're learning from should probably tell you. Try googling for "protocol collect specimens bacteria <whatever source you need to know about>". - Mgm|^(talk) 08:07, 11 July 2006 (UTC)

sepsis

breif backround about sepsis?

• Please write any future questions in full sentences and try searching before you ask a question. See sepsis. - Mgm|^(talk) 08:08, 11 July 2006 (UTC)

Sepsis. --Proficient 23:04, 12 July 2006 (UTC)

Equivalent term for BSS in UMTS world

What is the equivalent term for BSS (Base Station Subsystem) in the UMTS (3G) world?

Laparoscopic excision of moderate endometriosis

What is a laparoscopic excision of moderate endometriosis? A friend of mine recently got that, and has generally been feeling more down than usual ever since. So I'm curious as to what this is exactly, and what it means to the person who has it done to them? Mathmo 09:04, 11 July 2006 (UTC)

Endometriosis#Treatments and Laparoscopic surgery are good starting points. If you want more specific information, then try [1] and [2]. If you have access to a university library, you can probably get the full articles.-gadfium 09:36, 11 July 2006 (UTC)

AFTER EDIT CONFLICT:::Laparoscopic surgery is surgery with tiny incisions. Endometriosis is the propagation of uterine tissue in the abdominal cavity. So they performed a kind of D&C in her abdomen, scraping uterine tissue away from organs, and/or muscles, and/or whatever, without cutting her open, but rather by making tiny incisions and guiding the instruments with the use of cameras. If she is under the care of a physician and s/he knows of your friend feeling down I wouldn't worry about something serious like a slow bleed, but even laparoscopic surgery is still surgery, so she might just be recovering. Or she might be adjusting to the changes in hormone levels due to less uterine tissue? (I don't know if this is an issue, but it might be).--Anchoress 09:46, 11 July 2006 (UTC)

holy shit

Is this real, or someone's conspiracy theory? 87.97.8.96 13:17, 11 July 2006 (UTC)

• Based on the amount of references, I would say it's real, but you'd have to check if those sources are reliable and not written by someone with an agenda. - Mgm|^(talk) 12:39, 11 July 2006 (UTC)

I believe the general gist of it - that Imperial Japan conducted all manner of horrible experiments on Chinese prisoners - is pretty well established. Whether all of the specifics in that article are true I'm not sure. The Japanese of that period were not exactly the nicest people in the world. Try List of Japanese war atrocities. --Robert Merkel 12:54, 11 July 2006 (UTC)

I'm especially interested in whether these parts are just someone's conspiracy theory:

“ [...]Many experiments were performed without the use of anesthetics because it was believed that it might affect the results.

[...]

• Prisoners were amputated limb by limb to study blood loss.
• Arms were cut off and reattached to opposite sides.
• Limbs were frozen and sawn off.
• Stomachs were surgically removed and the oesophagus was reattached to the intestines.
• Parts of the brain, lungs, liver, etc. were taken out.

[...]

• Prisoners were placed into highly pressurized chambers until they died.
• Frostbite experiments were conducted on prisoners to determine how long humans can survive when exposed to extreme temperatures.
• Temperature experiments were performed to determine the relationship between temperature, burns and survival.
• Prisoners were placed into centrifuges and spun until they died.
• Animal blood was injected into humans.

[...]

”

The above are just some statements especially suspect to me (I added the emphasis). What is the article for allegations (or convictions) at Nurenburg of Nazi criminal experimentation on Jews? 87.97.8.96 13:17, 11 July 2006 (UTC).

See Unit_731#Politicization_of_history. A Japanese court acknowledging the truth of the allegations is good enough for me. --Dweller 13:23, 11 July 2006 (UTC)

• The Nazi experimentation article is Nazi human experimentation. --Fastfission 14:49, 11 July 2006 (UTC)

you know, nothing here Nazi human experimentation strikes me the same as "Stomachs were surgically removed and the oesophagus was reattached to the intestines" or "Arms were cut off and reattached to opposite sides." Am I missing something? (btw, thank you Dweller, Fastfission and also Robert Merkel and Mgm for your answers.)15:14, 11 July 2006 (UTC).

Unfortunately, both in Japan and germany of that era, such experiments were the case. I can't say if those, specifically, were, but in general, yes. People did some exceptionally horrible things to people, in the name of "experimentation on subhumans who we don't have to care about", whether Russians, Jews, or Chinese. FT2 ^{(Talk | email)} 18:34, 11 July 2006 (UTC)

Note that torturous "experiments" such as food/water deprivation, low and high pressure, hypothermia and extended holding in water, frostbite and altitude, animal blood, chemical weapons, and the like were all documented in Nazi Germany too. FT2 ^{(Talk | email)} 18:39, 11 July 2006 (UTC)

thanks, FT2. I wonder if the U.S. has ever done anything similar that we know of? 82.131.185.74 21:24, 11 July 2006 (UTC).

history is written by the winners. Xcomradex 21:48, 11 July 2006 (UTC)

The reference desk is not a soapbox. Please give factual answers rather than offensive innuendo. The actual answer is: No, nothing anything like this that we know of. -- SCZenz 22:11, 11 July 2006 (UTC)

Oh no? See this site, which includes a number of experiments either sponsored by the U.S. or which at least took place there. Granted, none approach the scale of Unit 731, but many are similar to some conducted by Unit 731; for instance, an entry for 1942 reads "Harvard biochemist Edward Cohn injects sixty-four Massachusetts prisoners with beef blood in U.S. Navy-sponsored experiment." --Ginkgo100 ^{talk · contribs} 03:04, 12 July 2006 (UTC)

exactly my point. Xcomradex 23:33, 11 July 2006 (UTC)

It's not a wartime atrocity, but Tuskegee Syphilis Study is a pretty sickening account of an unethical experiment in the US. Abu Ghraib torture and prisoner abuse doesn't involve surgery, but I'd describe it as an atrocity.-gadfium 02:59, 12 July 2006 (UTC)

Also see Operation_Midnight_Climax Dr Zak 03:55, 12 July 2006 (UTC)

and before accusations of anti-americanism come out - Ronald Maddison. Xcomradex 03:47, 12 July 2006 (UTC)

Indeed. Much phosphorus chemistry done at Porton Down was declassified after the War, and was published complete with tests on human subjects in the Journal of the Chemical Society in the early 1950s. Dr Zak 03:55, 12 July 2006 (UTC)

And its not just the Anglo-Americans, the SADF and Khmer Rouge face allegations of mistreatment and unethical human experimentation. Rockpocket 03:56, 12 July 2006 (UTC)

indeed, eg Operation Coast. i'd say everyone has their dirty little secrets, the only difference being the depth of the coverup. if its a vanquished enemy, then it all comes out eventually. even if it takes fifty years - Nazi War Crimes and Japanese Imperial Government Records Interagency Working Group. Xcomradex 04:02, 12 July 2006 (UTC)

302 windsor ford V8 torque specifications

hello im an apprentice motor mechanic and i need help rebuilding a 302 windsor but do not have the torque specs or much other info for that matter if u can help it would be greatly appretiated gibbo_22@hotmail.com.rob.

Turns out we have a pretty nice article about windsor engines - it looks like there is a section on the 302. Look here: Ford Windsor engine. Good luck --Bmk 13:43, 11 July 2006 (UTC)

Little unknown dead critter

Some mis-directed little mammal found its way into my backyard somehow, and my dog saw this as a wonderful opportunity for practicing her hunter-killer skills (ignoring my commands to just leave it alone). Once she really got ahold of it, she killed him pretty quick.

It's not a mammal that I'm familiar with, so I thought if I posted a few pictures of it here maybe someone could identify it. It looks like a burrowing animal, like some sort of gopher, but none of the ground squirrels I was able to find pictures of via Google Images really looked like it—it is a beefy little guy, not lithe like a squirrel. I'm in the greater Boston area if that is of any help.

So, if you can stomach a dead (but pretty cleanly killed) critter, here are the pictures: laid out on its back, detail of face.

Thanks. --Fastfission 16:11, 11 July 2006 (UTC)

How big is it? It looks a little like a mole, based on the claws and teeth but it's hard to tell. --LarryMac 16:13, 11 July 2006 (UTC)

That bag he's in it a standard supermarket bag, probably a foot in length or so. Which puts his body about 8 inches long or so without the tail. I've gone over all of the rodents on Commons and he looks most similar to a marmot or a groundhog to me. --Fastfission 16:23, 11 July 2006 (UTC)

Actually, the parallels between this image and the scene just witnessed are incredible! (Even the dog looks similar). --Fastfission 16:27, 11 July 2006 (UTC)

Poor little guy. He was probably just trying to figure out how much wood he could chuck (if he could, of course). --LarryMac 16:36, 11 July 2006 (UTC)

Yeah, I have no idea why he chose our yard out of all of the more hospitable (and dog-free) yards in the area. But thems the breaks for small mammals; our dog wouldn't dare miss an opportunity to go after them (which sometimes has awful consequences, such as the two times she went after skunks). --Fastfission 19:42, 11 July 2006 (UTC)

The nose doesn't look like a mole, and from the teeth I'd say it's some type of rodent. Do you have a pic of the tail ? StuRat 22:00, 11 July 2006 (UTC)

It's almost certainly a type of burrowing marmot. I would agree that it's most likely a woodchuck (a.k.a., groundhog). Mind if I ask where you live? – ClockworkSoul 22:32, 11 July 2006 (UTC)

The best I have of the tail is the first one—it was bushy but not too bushy. I'm in the Boston area, but far enough out that we sometimes get critters in the backyard. --Fastfission 01:40, 12 July 2006 (UTC)

Cannibus and Coffee

What is the link between the two? What are the effects? why is cannibus sold in "coffee shops" in amersterdamn?

Thank you - SIXsixSIX

The last time I was in Amsterdam, if you wanted a smoke in a 'coffee shop', you had to buy a coffee/other drink/snack from the establishment. They didn't like it if you just went in, sat down and started rolling your own... --Kurt Shaped Box 19:28, 11 July 2006 (UTC)

There isn't any chemical link between them. They each act on completely different receptors and have much different effects. I guess the closest link would be that they are both legal mind-effecting that have low addiction potential, almost no overdose potential, and appeal to a wide range of people in similar demographics. Crazywolf 19:31, 11 July 2006 (UTC)

It's also pretty nice to have a coffee and a donut with your spliff. I personally find that ganja makes food and drink taste better. There is one place where you can have a full English breakfast and a joint on the side... --Kurt Shaped Box 19:37, 11 July 2006 (UTC)

There's a good couple of paragraphs in our Coffeeshop article. NB, the correct spelling is Cannabis. --LarryMac 19:40, 11 July 2006 (UTC)

Security of cordless telephones?

I bought a dual-handset DECT phone today. Now I've got it home and plugged it in, I find myself wondering about the privacy/security implications of using a cordless phone. Would it be possible for someone to intercept the radio waves and listen in to my private calls? What if someone nearby had the same type of phone? Would they be able to pick up my calls on their handset? --Kurt Shaped Box 19:24, 11 July 2006 (UTC)

The answer is yes - unless you have a very expensive counter-espionage telephone handset that encrypts the signal before sending it to the base station, anyone with a frequency-tunable receiver in the frequency range of phone handsets can drive by your house and pick up your signal. In fact, if you have some kinds of wireless speakers or other wireless devices, occasionally you'll pick up your own conversation over those devices too. Of course, phone handsets aren't very powerful, so anyone spying on you would have to be pretty close to your house to get a good signal. That's to the best of my knowledge - someone correct me if I'm off the mark. If you're very concerned, you can always step into a Faraday cage as long as you bring your base-set with you. But that kind of negates the convenience of the handset in the first place.

Wit directional antennas, they could pick up your signal from quite a bit further away than the distance your phone can be from your base and still work. If you put the base in the corner of your house and put a directional antenna like the ones at www.freeantennas.com on it, you could block off the signal from being heard in that direction, at least.

For your second question, someone with the same type of phone would not be able to pick up your calls because they are all tuned to their unique frequency for that exact reason (unless you bought your handset from a really dumb company).

Another thing to consider - people like NSA officers can pick up your calls anyways on a cord phone - nowadays they don't even need an individual warrant for your phone tap. --Bmk 20:23, 11 July 2006 (UTC)

If I am not mistaken, Mr. Box is less concerned with the NSA than you or I, as he lives in Britain. (Is that right, Kurt Shaped?) --Ginkgo100 ^{talk · contribs} 02:42, 12 July 2006 (UTC)

Thanks guys. It's no biggie and I have no reason to believe that anyone would be trying to deliberately intercept my calls. I was more concerned about neighbours/people in the other flats accidentally hearing my conversations on their phones... --Kurt Shaped Box 21:23, 11 July 2006 (UTC)

The must common security risk is giving out credit card info over a cell phone. Always use a land line for that instead. StuRat 21:46, 11 July 2006 (UTC)

That's a very valid point. I'll definitely use my old standard phone if I'm going to be doing any of that... --Kurt Shaped Box 22:39, 11 July 2006 (UTC)

It's not quite as bad as people make it out to be. If your phone uses spread-spectrum (DSSS or FHSS), then your call is quite safe. While not encrypted, it is spread across multiple frequencies (either all at once or time-sliced) and so without very specific equipment your calls are safe. This is often used in the 2.4 GHz (and higher) phones as the phone have to share the frequencies with lots of other devices (WiFi, microwaves, etc.) and this technique reduces the interference. If your phone is older or cheaper, then interception is easier. Modern cell-phones that use any sort of digital (as opposed to) analog network are also very difficult to intercept where older cell-phones using analog networks are very easy to intercept. —Bradley 23:26, 11 July 2006 (UTC)

Are you worried the gulls will overhear you arranging fights with magpies for them? =) --Ginkgo100 ^{talk · contribs} 02:44, 12 July 2006 (UTC)

I picture the gulls and magpies using his credit card info to buy weapons in an ever escalating arms race, LOL. StuRat 22:31, 12 July 2006 (UTC)

Negative effects of ameteur massage

Is there a situation where massaging a sore muscle can make it hurt worse in the long run? Crazywolf 19:37, 11 July 2006 (UTC)

The type of massage where you ram an elbow into the muscle could hurt, but a light touch massage can't hurt anyone. StuRat 21:40, 11 July 2006 (UTC)

(removed irrrelevant duplicate comment; now in its own section (about MP3)) -= Mgm|^(talk) 22:04, 11 July 2006 (UTC)

Thanks for your advice, but when I tried that my girlfriend complained that the jukebox was crushing her neck. Also, I copied your question to its own section Crazywolf

The kidney region is sensitive. I've never had a massage, but I've been in many fights (mainly required combat training). It doesn't take much of a punch to the kidney to cause a few days of soreness. I assume that too much sharp pressure will cause a similar lingering pain. --Kainaw ^(talk) 01:18, 12 July 2006 (UTC)

So true. I once had such a hard massage there that the next day I had blood in my urine.--Anchoress 02:45, 12 July 2006 (UTC)

Falling off a building?

Are there any statistics of how likely I am to die if I fall off the 24th storey of a building versus, say, the 4th storey? I live on the 24th storey of an apartment building (technically the 23rd actually), and I'm curious approx. what are the odds of survival or death if I were to fall off.--Sonjaaa 20:17, 11 July 2006 (UTC)

"Hardly anybody can survive a fall of more than six storeys onto hard concrete." claims [3]. I find that pretty reasonable. Your chances of surviving a 24 storey fall are very low, I'd wager. I'd suggest not falling off, if you have the choice. 128.197.81.223 20:25, 11 July 2006 (UTC)

Certainly, it depends on the manner of landing, but in all likelihood your body will stop in a foot or less. Figure 240 feet fall / 1 foot stop = 240 g's. A 150 pound man at 240 g's would have an impact force of 36,000 pounds - roughly the weight of 20 cars! Your chance of surviving is probably less than 1% under those conditions. -User: Nightvid

I would guess that concrete or hard soil are pretty much lethal at that height - there might be a one-in-a-million chance of survival if you happen to land just right by some freak chance, but you'd certainly spend a very long time in hospital. Water might be survivable if you manage a perfect dive, but at that speed, you'd very probably still break either your arms or your legs (and probably also inflict some more damage on your body). You could try decreasing the water's surface tension by throwing out lots of soap before you jump, assuming you have the time for that. Your best bet for survival, however, is probably several feet of very soft snow - so depending on where you live, try to fall out the window in winter :P -- Ferkelparade π 21:27, 11 July 2006 (UTC)

Falling from beyond 4 or 5 stories brings on the "worst case" scenario: a speed likely to kill regardless of the type of landing made. The only suggestion (as per the discussions that have been had in the past) is to try to land in a tree. A tall/wide enough tree can provide the gradual deceleration needed to make it down alive. Of course, this assumes the tree itself doesn't kill you first.

• I read about a kid surviving a fall of the 11th floor just this morning in the paper (that's 12th floor to you Americans I think). It all depends on the circumstances: the spot you land and how you land. - Mgm|^(talk) 22:02, 11 July 2006 (UTC)

If you mean this story [4], then it's 11th floor to us too (since the story is from the states). It may be worth noting that the original question-asker didn't mention landing on the ground. One could fall off the top of a 24 storey building and land quite safely atop a neighboring 23 storey building. :) 128.197.81.223 22:58, 11 July 2006 (UTC)

Yeah, or if a flock of birds breaks your fall on the way.--Anchoress 02:48, 12 July 2006 (UTC)

Something to do with MP3 CDs

I have created an MP3 master with 33 audio essays, running about 4 1/2 hours amd 187 mb. I've been given a Data ISO and a Jukebox ISO. Which would be the most versatile in creating a disc that could be played on laptops, iPods and MP3 compatible CD players? Thank you. Tucker

If I were the last man on Earth

Frequently, I hear on fims 'I wouldn't sleep with him if he was the last man on Earth'. If I actually was the last man on Earth, and there was one last woman, would we be able to repopulate civilisation given the lack of genetic diversity and the need for inbreeding involved? I assume the answer is 'no', but would it be possible nevertheless? --russ 23:20, 11 July 2006 (UTC)

I would say yes. The lack of genetic diversity would be a problem, but humans have such an advantage over other species at this point due to our intelligence that I would bet we still could survive. Hopefully, the first generations would also get a boost from whatever was left behind the disaster from the old human race. Eventually genetic diversity would reappear as a result of mutations. StuRat 23:43, 11 July 2006 (UTC)

Also note that if only two people were left on Earth, unless they happened to be right next to each other, they would have a heck of a time locating each other, unless they both happened to be HAM radio operators. StuRat 23:48, 11 July 2006 (UTC)

Sounds like a B-movie to me! —Keenan Pepper 00:18, 12 July 2006 (UTC)

Some pretty good non-B movies have had the "last people on Earth" scenario, too... check out The Quiet Earth for one. Grutness...wha? 04:00, 12 July 2006 (UTC)

What if the only 2 people left were brother and sister? Or mother and son? Or grandfather and granddaughter? Brings a fresh new meaning to the song "If You Were the Only Girl in the World". JackofOz 00:35, 12 July 2006 (UTC)

I don't think it would make a big difference. If the last 2 people weren't brother and sister, the next generation of couples would be (or father and daughter, mother and son), so you'd have the exact same problems. Keep in mind that a lot of the huffuffle about inbreeding comes from the fact that it's a cultural taboo, and not because of the health risks.  freshofftheufoΓΛĿЌ  01:40, 12 July 2006 (UTC)

A brother and sister would have 68.5 unique chromosomes, on average, while two totally unrelated individuals would have 92 unique chromosomes. StuRat 02:05, 12 July 2006 (UTC)

There is actually one benefit to inbreeding, it rapidly removes recessive gene disorders which result in offspring who die or are unable to reproduce (such as sickle cell anemia). Thus, the prevalence of the bad gene is reduced much faster from the gene pool. StuRat 02:05, 12 July 2006 (UTC)

Its not entirely true to suggest the health risks are inconsequential, though. As many as 55% of British Pakistanis are married to first cousins (who share 25% 12.5% of their genes, compared to brother/sister/parent/children, who share 50%). As a consequence British Pakistanis are 13 times more likely to have children with genetic disorders than the general population - they account for just over 3% of all births but have just under a third of all British children with such illnesses, According to the BBC. Now imagine the health effects if the level of genetic relatedness was double four times that seen in first cousin marriages, you can see why incest is illegal in most countries. The reason it is culturally taboo is because, historically, it leads a reduction in genetic fitness which manifests as disorder and disease.

StuRat is right in that it will weed out the recessive alleles pretty quickly, but that is not exactly an advantage when you have a single founding pair. I would rather risk propogataing a few recessives to build up my population, rather than risk killing my entire F1 generation to get rid of the recessives. Moreover, recessive alleles are the currency of evolution. In other words, being European, i would personally choose a randy young Bantu or Aboriginal lass to repopulate the earth with, rather than my sister! Rockpocket 03:31, 12 July 2006 (UTC)

Not to say that BBS doesn't know what they are talking about, but I can't find where they got their information, and there is an easily found peer review article on this very subject published in nature reviews genetics that suggest much lower effects. I'm going to finish reading it and then summarise what it says and provide a reference to it when I'm done. Until then, don't put too much stock in what BBS says about an issue as controversial as this one. Crazywolf 04:32, 12 July 2006 (UTC)

Also, first cousins share 12.5% of their genes on average, not 25%. Please verify your facts a little bit in the future, especially if they are particularly politicized, like these. Crazywolf 04:36, 12 July 2006 (UTC)

Ok, I found out where BBC was getting their 13 times number, but their statement was simply not true. A representative study of births was done in Birmingham, which compared British Northern Europeans and British Pakistanis. .04% of the Northern European couples were related, while the relatedness of the British Pakistanis in Birmingham was equivalent to 70% of the couples being first cousins. Only 57% of the couples were related, but some had parents that were related. The Northern Europeans had a 4.6% prevalence of genetic disorders in the first 5 years of their life, while the British Pakistanis had a 7.9% prevalence. So they had less than twice the congenital birth defects of Northern European children, of which 25% of this increase was not related to the the relatedness of the couples. That is a substantial increase, but certainly not 13 times as much. The 13 times figure came from a misinterpretation of genetic disorder as meaning only recessive genetic disorders, which make up a small fraction of the genetic disorders in the Northern European population. Unfortunately, the study wasn't large enough to determine whether the difference in recessive genetic disorders was related to factors other than the relatedness of the couples, as too few of the British Pakistani couples were unrelated for significant comparison. Genetic counselling and customary consanguineous marriage. Nature Reviews Genetics, Mar2002, Vol. 3 Issue 3, p225, 5p

Crazywolf 05:12, 12 July 2006 (UTC)

Thank you for clarifying that. I apologise for repeating misleading information from what is normally a well respected source. I simply recalled reading about a study on the BBC a few months back when i noticed the question and figured the BBC's report didn't quite tally with the suggestion that the health risks of consanguineous children are secondary to cultural factors. I think the wider point remains valid, irrespective of the BBC's innaccurate reporting of the primary source. I take issue with the suggestion that my comments were "particularly politicized". The health implications of consanguineous children strongly inform public health policy in many countries. Irrespective of cultural or political opinion on the matter, it makes much more sense to outbreed a founding pair, rather than inbreed, if reproductive fitness is your goal. Both human and animal models bear this out. I'm not sure what political agenda you inferred from that, but i assure you, there was none implied. Rockpocket 07:41, 12 July 2006 (UTC)

"Honey, we have to repopulate the Earth". Sounds like a great excuse to have sex. --mboverload@ 02:23, 12 July 2006 (UTC)

Needing an excuse to have sex is not a concept with which I am familiar. Must be some new-fangled American thing. LOl :--) JackofOz 01:21, 13 July 2006 (UTC)

I'm surprised no Christians have jumped in to tell us that if we did it once, we can do it again :) --Bmk 02:27, 12 July 2006 (UTC)

In a way, that exact thing is happening in the Utah FLDS community, where apparently 50% of the polygamist sect is directly descended from one couple, and since both ancestors had the same genetic disorder, a disproportionate number of offspring in the community is affected. Link HERE.--Anchoress 02:54, 12 July 2006 (UTC)

Two humans is not diversity to have a viable population. Take the issues facing the Pitcairn Islands (where all the inhabitants trace their lineage back to 6 or 7 people), and magnify the problem a hundredfold. Raul654 04:36, 12 July 2006 (UTC)

But the population of Pitcairn Island hasn't all died off, have they ? This is my point. Humans have such an advantage over other species due to technology that they would have to have an extremely serious genetic disease to all die off. StuRat 22:42, 12 July 2006 (UTC)

As long as our new Adam and Eve can breed successfuly and raise at least some of their children to child-bearing age, a viable population could be eventually achieved. Of course, it would mean saying goobye to monogamy, accepting strict eugenics and controlled breeding, accepting a high level of infant mortality, maximising the children borne to women with successful blood lines, euthanasia to conserve scarce resources etc. etc. - not pretty, not fun, and definitely not civilisation as we know it, but possible. Gandalf61 11:15, 12 July 2006 (UTC)

Scarce resources ? With only a few people left on the planet ? Perhaps locally scarce, but the solution there is to spread out, not kill each other. StuRat 22:42, 12 July 2006 (UTC)

It is quite possible that resources could be scarce because of the collapse of society. With millions of poeple, everyone can specialize: farmer, teacher, builder, etc. With just a few people, everyone has to be more of a generalist, which leads to inefficiency. Also, some infrastructure would be impossible to maintain. 2 or 4 or 8 people can't keep the power plant running and the water system pumping, and the sewer system working... Without that type of infrastructure, efficiency would plummet, and resources would very likely become scarce. Johntex\^talk 01:46, 13 July 2006 (UTC)

I agree that small numbers of people would not be sufficient to maintain the infrastructure. However, the solution to this is by no means to kill off some of the few people there are. At worst, they should be sent off to go find resources elsewhere. StuRat 14:31, 13 July 2006 (UTC)