Wikipedia:Reference desk/Archives/Science/2009 October 8

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October 8

Continental shift

Well, I'm interested in plate tectonics, and recently I heard about the expanding earth theory. I'm not sure you are all familiar with it, but basically it says that there has been no continental shift, but instead constant drift and expansion due to the earth constantly expanding. What evidence is there against this? It seems ridiculous to me, but to be honest I have not taken it upon myself to study the "(not at all scientific) theory" in detail, so I believe my refutations would be off the mark. Also, I've been looking over the grander sweep of evolutionary history and continental shift, and I was wondering if I could find a full animated model of all past and present positions of the continents. Thank you. —Preceding unsigned comment added by 69.232.239.99 (talk) 06:49, 8 October 2009 (UTC)

We have a page, Expanding Earth. The short story is that this was a popular idea in the 50s and 60s, but paleontological data has since shown that the Earth's radius is within a few percent what it was over half a billion years ago. Someguy1221 (talk) 07:03, 8 October 2009 (UTC)

There is also the lack of a convincing mechanism for the expansion, which has to explain how all the oceans have appeared during the last 250 million years and why nothing happened before that.

Regarding animated plate reconstructions (we have no article for this, but it is on my 'to do' list) there are several available online.

• Chris Scotese's Paleomap project [1]
• Trond Torsvik's Geodynamics group [2]
• University of Texas at Austin's PLATES project [3]

There may well be others out there, but these should be a start. Mikenorton (talk) 08:52, 8 October 2009 (UTC)

As Mike says, the Expanding Earth folks have no way of explaining marine fossil assemblages before Pangaea (which exist across the Earth). They also have no way to account for the drastic change in global volume. Their hypotheses are inconsistent with seismic imaging of tectonic plates moving. One of their many arguments is that the length of mid-ocean ridges (where crust is created) is greater than that of subduction zones (where crust is destroyed) and that the Earth must therefore be getting larger, but they forget that the plate velocities at subduction zones are much greater, and therefore the flux of material is conserved. Awickert (talk) 08:19, 11 October 2009 (UTC)

Relaxation and schizophrenia

I'm aware that there is conventional medical wisdom that deep relaxation can bring on a relapse in schizophrenics. I did a Google search yesterday hoping to find some research that confirms this, but all I could find was guidelines saying things like "it is accepted that relaxation can worsen some symptoms of schizophrenia" - not actual research papers. Can anyone (maybe with some access to the relevant journals) find a paper for me that confirms this? Many thanks.--TammyMoet (talk) 12:08, 8 October 2009 (UTC)

Looks like this could be what you are looking for. I don't have access to the full text at the moment, but the abstract looks promising. Rockpocket 21:44, 10 October 2009 (UTC)

Progressive muscle relaxation (a different animal) can be soothing for schizophrenics. (Chen WC; Chu H; Lu RB; Chou YH; Chen CH; Chang YC; O'Brien AP; Chou KR. Efficacy of progressive muscle relaxation training in reducing anxiety in patients with acute schizophrenia. Journal Of Clinical Nursing [J Clin Nurs] 2009 Aug; Vol. 18 (15), pp. 2187-96.) Using MEDLINE and EBSCOhost I found no good studies supporting what you say, and a few equally mediocre ones that said the opposite. - Draeco (talk) 03:42, 11 October 2009 (UTC)

Thanks for these, guys - mainly confirming what I found. Interesting. --TammyMoet (talk) 08:57, 11 October 2009 (UTC)

Wheel alignment

If a car's wheel alignment is not correct (specifically, the car doesn't travel perfectly straight when the steering wheel is in the neutral position), what are the possible consequences of not getting it repaired? ike9898 (talk) 13:36, 8 October 2009 (UTC)

Well, it is going to depend on how bad it is. Generally, what will happen is that you will get more fatigued if you are driving for long periods, and you fuel mileage will be somewhat reduced. I think it might cause uneven tire wear, but I am not positive on that. Googlemeister (talk) 14:21, 8 October 2009 (UTC)

At the very least, substantially reduced tyre life - if they are always scrubbing they will wear out quickly and unevenly. At the worst, an accident as the car veers one way or another and hits another car or solid object. This can be easy and cheap to fix (it may simply be a steering gear adjustment) and I would strongly recommend getting it looked at. --Phil Holmes (talk) 14:21, 8 October 2009 (UTC)

Echoing the above (tire life and fuel mileage in particular), but a key possible consequence hides a little deeper: why is the alignment not correct? If the wheels were just misaligned, then there's no immediate danger. If the wheels are misaligned due to some other fault, you may be at serious risk. For example, my wheels last went out of alignment because I had a wheel bearing that was almost toast, and the bearing failure could have been catastrophic. Misalignment was a primary cause of the maintenance that found the root issue. — Lomn 14:26, 8 October 2009 (UTC)

Thank you all. It's possible that the misalignment was caused by hitting the curb too often while parallel parking. ike9898 (talk) 16:50, 8 October 2009 (UTC)

Wait, wait...there is no "neutral position" for a steering wheel. If your ONLY symptom is that the wheels do not point straight ahead when the steering wheel bar is horizontal - then that may just mean that at some time in the past, someone removed it for some reason and didn't put it back on the right 'notch' of the spline...in which case, there might be nothing wrong at all. However, if you let go of the steering wheel while driving straight - and the car then pulls to one side (ie, you have to exert some force in order to keep the car going straight) then you have an alignment problem that you really should get looked at because it might be indicative of something really serious going on...and you'll wear out your tyres and become fatigued by long trips...but dying when the bent strut breaks and one of the wheels turns 90 degrees at 70 mph is really the bigger concern here! If the car pulls to one side when breaking - but not when in normal motion - then there are different problems, which still need to be attended to. SteveBaker (talk) 17:32, 8 October 2009 (UTC)

There is an adjustment in the steering mechanism for the steering wheel orientation, besides possible misalignment on the steering column (is that even possible?). A true bozo of a mechanic did an alignment on my car once and immediately after I had to hold the wheel 15 degrees to one side to drive straight. He claimed that it was just due to the "crown of the road" and that I probably hadn't noticed it before. When I complained to a manager, he got the necessary tools and adjust the steering position. Edison (talk) 18:39, 8 October 2009 (UTC)

I'm surprised that you've seen steering wheel adjustments - and misalignment of the steering wheel on the steering column is only too possible! Admittedly, I only tend to work on ancient relics rather than modern cars - but certainly on the few I've restored, you'd either have to dismantle the steering box - or (much, MUCH easier) drive the car into your garage with the wheels dead straight - then remove the big nut that holds the steering wheel onto the column, lift it off (CAREFULLY - don't want to yank any of the wires) and put it back in the right position for straight wheels. The shaft has a spline on the top (like the teeth on a gearwheel) that meshes into a hole under the steering wheel. You can reposition it in about (maybe) 10 degree increments. VERY IMPORTANT NOTE: If you have an airbag - you'll need to disconnect the car battery before you even think about doing this!! But if there is a proper adjustment mechanism somewhere then by all means use that. Anyway - only do this if the car DOESN'T pull to one side when you let go of the steering wheel. SteveBaker (talk) 20:36, 8 October 2009 (UTC)

Minor drifting to the left or right when you let go of the wheel can also be caused by a poorly inflated tire on one side. Given that air is cheap it is generally worth checking the state of your tires before asking a mechanic to look at the alignment. You'd be surprised how many alignment complaints are really tire problems that people didn't notice. Dragons flight (talk) 22:36, 8 October 2009 (UTC)

Thanks again guys! ike9898 (talk) 17:12, 9 October 2009 (UTC)

Raw potato (inspired by question about cookie dough above)

When I was very young, my mom gave me a piece of raw, peeled potato and I really liked it. Afterward, I asked for more on many occasions, but my mom was convinced it wasn't good to eat raw potato. I've also never seen raw potato used as food in any cuisine. Is there anything wrong with eating raw potato? ike9898 (talk) 13:47, 8 October 2009 (UTC)

Raw potatoes are harder to digest than cooked ones, but are otherwise pretty edible. Don't eat green potatoes under any circumstances, they are likely toxic (see Potato#Toxicity). In general, cooking potatoes reduces their toxicity, but it should be fairly unlikely to have problems assuming they aren't green. --Mr.98 (talk) 13:57, 8 October 2009 (UTC)

In principle, Mr98 is correct that raw potatoes are no more toxic than boiled ones. But cooking doesn't reduce their toxicity, as mentioned in solanine. Frying can do this, because you basically extract the solanine, but cooking in water is not hot enough to do much to the toxin. --TheMaster17 (talk) 14:09, 8 October 2009 (UTC)

I vaguely recall that they are very indigestible. The problem (I believe) is that starch can only be converted to digestible sugars by saliva in the mouth or in the duodenum - or in the colon (by bacterial break-down). As our article on starch says "Digestive enzymes have problems digesting crystalline structures. Raw starch will digest poorly in the duodenum and small intestine, while bacterial degradation will take place mainly in the colon."...so the only place where raw starch can be converted to sugars is in the mouth. But the cells of the potato (which contain the starch) are surrounded by a fairly robust cell-wall which doesn't break much as you chew. So the saliva can't get to the starch to break it down - and later on, the gut can't deal with it because of the crystalline properties of the stuff. Cooking the potato breaks down the cell walls and allows the enzymes in the gut to deal with it. You'll notice that if you chew a piece of bread or cooked potato (lots of starch - easy to get at), it tastes sweeter and sweeter the longer you chew it...because your saliva is converting the starch to sugars. But no matter how long you chew on raw potato - it never seems to change taste. So your mom was right about the digestibility thing. I wonder whether having large amounts of undigested starch making it through to the colon - and being broken down there by bacteria - might somehow be bad for you. Whether that means that it's not safe to eat it - I'm not so sure. But that's getting into the realms of medical advice. SteveBaker (talk) 17:23, 8 October 2009 (UTC)

There are instances when eating your own feces can have a beneficent effect (or so I have heard). With this in mind I would not ask you to swear off raw potatoes. Vranak (talk) 17:38, 8 October 2009 (UTC)

You've really derailed the thread with that one, which is sort of uncool, but I have to disagree that eating one's own feces brings any benefit. Cite sources here on the refdesk, please. Comet Tuttle (talk) 20:50, 8 October 2009 (UTC)

Definitely think Vranak's source is not correct, don't believe everything you hear. Even if you are dying of hunger you should not eat your own feces! It will make you worse not better. Conversly if you are dying of thirst, you should definitely drink your urine, it will hydrate you much more then harm you. Vespine (talk) 00:01, 9 October 2009 (UTC)

Hey, I hope my source is mistaken as well. Vranak (talk) 20:12, 9 October 2009 (UTC)

ESAD. Cuddlyable3 (talk) 22:34, 9 October 2009 (UTC)

Coprophagic café coronary. Axl ¤ [Talk] 18:31, 10 October 2009 (UTC)

On the other hand, potatoes with sprouts and potato leaves are always poisonous. Do not consume either, raw or cooked. ~AH1^(TCU) 14:00, 11 October 2009 (UTC)

carpal tunnel

Does wearing a watch increase chances of carpal tunnel from too much typing? —Preceding unsigned comment added by 218.186.12.253 (talk) 15:47, 8 October 2009 (UTC)

My own experience says "Yes, very definitely" - but I'm not a good statistical sample. SteveBaker (talk) 17:24, 8 October 2009 (UTC)

Only if the watch adds significant physical stress because of its weight or if the strap is too tight or loose. Cuddlyable3 (talk) 13:43, 9 October 2009 (UTC)

I found that the strap presses against the underside of your wrist as you rest them on the desk (or whatever) - and that was a cause for problems for me. I had problems in only the wrist with the watch - and when I stopped wearing it, things got much better. But as I said - you can't really extrapolate from a single example. SteveBaker (talk) 14:04, 9 October 2009 (UTC)

Time Zones

If I need to organize a global business meeting with live participants in a variety of time zones what is the best way to schedule it? It seems like no matter when I schedule things it’s always some crazy time in either Sydney, Jakarta, Paris or Rio. What’s the best compromise or is there a better way to coordinate this? TheFutureAwaits (talk) 16:59, 8 October 2009 (UTC)

This is essentially the problem the Formula 1 organisers have. Their solution is to run most races at noon UTC on a Sunday, which caters best for their core audience in Europe, and makes for sensible evening viewing in Asia, where they're hoping to expand. It disfavours the Americas, but not to the extent that the core south american audience is getting up insanely early. That's really the best you can do. This mostly screws Sydney, however. -- Finlay McWalter • Talk 17:26, 8 October 2009 (UTC)

F1 can show repeats at more convenient times, a meeting can't, so it is a little different. F1 can just decide that they can't reasonably cater to Australia, say, and choose a good time for everyone else. For a business meeting you have to compromise. --Tango (talk) 17:29, 8 October 2009 (UTC)

I would draw a line and mark it from 0 to 24 GMT and then draw on it the office hours in each of those countries. If there is a time in all the office hours, choose it, if there isn't choose one that is in most of the office hours and not too far away from the rest. --Tango (talk) 17:29, 8 October 2009 (UTC)

The problem is more how to make fair arrangements in requesting employees in Sydney and Jakarta attend this meeting. It's vital they be involved yet we have to run from 12PM-3PM in New York. So is it totally unreasonable for these employees to attend a (3AM-5AM Sydney / 11PM-2AM Jakarta) meeting even if this will only happen once a quarter? TheFutureAwaits (talk) 18:18, 8 October 2009 (UTC)

Yes. I'd be pissed unless you rotate the schedule to hit everybody (I'd still be pissed, but at least I would not feel unfairly disadvantaged). Why is the NY time window nailed to the floor? If it's that important, fly them in in time to overcome jet lag, then fly them back. Or schedule a one week meeting yearly in a nice place. Or, better still, throw money at the problem. Hand them a bonus and have them bid for a slot ;-). --Stephan Schulz (talk) 18:27, 8 October 2009 (UTC)

• Yes, it is totally unreasonable to expect someone to attend a 3AM-5AM meeting. You're asking Sydney (or whatever office gets that time slot) to perform up to their usual high standards of professionalism at a time slot that human biology just plain hasn't equipped them for. If this meeting is "vital", then someone in Sydney could rightly perceive this as the sort of meeting where their future in the organization is on the line -- a smooth presentation could grease the wheels for a promotion, while inattentiveness could dash that chance. In all seriousness, concerns like that can often inspire far-flung offices to split from the mother company. That's why many global organizations either do away with these pan-global meetings, or else set aside a travel budget so that these meetings can be in person. --M@rēino 19:48, 8 October 2009 (UTC)

If the meeting has to be 12PM-3PM New York time, then I'm not really sure what can be done about it. If want to avoid holding the meeting while anyone in those cities should be sleeping, you've got Sydney at -10, Jakarta at -7, Paris at 0, Rio at +3, New York at +5, which has the largest gap between New York and Sydney (9 hours difference) so you'd want to hold it as early in the morning as possible in New York, which would be late, but not unreasonably late in Sydney. Although if the meeting is 3 hours long it's still sort of problematic. Starting at 6AM in New York is still finishing at midnight in Sydney. Rckrone (talk) 19:51, 8 October 2009 (UTC)

Oops, I think the signs are backward on those timezones. Rckrone (talk) 20:06, 8 October 2009 (UTC)

Bah, who doesn't do quarterly earnings at midnight?

Don't forget that in a couple of weeks time Sydney will be putting their clocks forward at the same time as London puts theirs back. This probably exacerbates rather than relieves the problem, as the time difference between the two suddenly goes from 9 hours to 11 hours.--Shantavira|^{feed me} 07:34, 9 October 2009 (UTC)

Advise the participants that the meeting will be reorganised this way: 1) Each participant gives a presentation at their local working time. The presentations are collected in videos that are passed as e-mail attachments westwards around the world. 2) After 24 hours everyone has seen everyone's presentation. A second 24 hour cycle can let everyone comment on everyone's presentation. Cuddlyable3 (talk) 13:37, 9 October 2009 (UTC)

freezing point

What is the freezing point of a 12 oz aluminum can of unopened Coca Cola Classic? The American recipe that uses corn syrup instead of real sugar. Googlemeister (talk) 18:49, 8 October 2009 (UTC)

Lower than 32F or 0C, and lower than equivalent Diet Coke, and lower than the same can opened.Above 0 F (see below) An empirical approach could answer the question. When it freezes, the top pops up and the bottom becomes rounded. I once put a can of (probably diet) pop in the deep freeze and after it froze, tried to use the pressure buildup to round out the bottom more (to make a Van de Graaf generator) by cranking the temperature down to minimum. At some very low temp, it burst the lid free and became a rocket and launched dramatically through the deepfreeze, leaving a rocket exhaust of Coke slush. Edison (talk) 18:58, 8 October 2009 (UTC)

http://questions.coca-cola.com/NSREExtended.asp?WhatUserSaid=At+what+temperature+will+soft+drinks+freeze%3F Livewireo (talk) 19:17, 8 October 2009 (UTC)

It was surprising that the Coke ws still liquid enough to squirt out as slush, by frozen enough to expand to the point it completely expanded the top and bottom of the can. Edison (talk) 17:56, 9 October 2009 (UTC)

Ice takes up 9% more volume than water. If a pop can is 120 mm tall, the top 5 mm contain no liquid, it is an approximately uniform cylinder, and the CO2 is negligible, then only about 56 mm (half of the pop) must be frozen for the can to be filled to capacity. If these assumptions are right (and they seem to be close per Edison's deep freeze experiment, in which there was still liquid present after the bulging out of the top and bottom of the can), the contents of the can must be partially liquid when it bursts. Awickert (talk) 08:26, 11 October 2009 (UTC)

Carbon neutral / entirely dependent on renewable energery

Anyone know of anywhere other than Somos in Europe that is totally dependent on renewable enegery or alternatively places that are totally carbon neutral? 188.220.144.215 (talk) 21:53, 8 October 2009 (UTC)

Do you mean just electricity? Because I don't think anywhere that has any cars would qualify otherwise. Unless you include some kind of offset system... TastyCakes (talk) 21:56, 8 October 2009 (UTC)

Essentially eletricity, althought if there was a place with an offset system I'd like to know where it was... 188.220.144.215 (talk) 22:10, 8 October 2009 (UTC)

Iceland. See Renewable energy in Iceland. --Stephan Schulz (talk) 22:12, 8 October 2009 (UTC)

I think Quebec would be a more impressive contender. Almost all (96%) of its electricity is produced by hydro and it has a population 25 times that of Iceland. I'm not sure about heating, I suspect many homes are heated by natural gas or even fuel oil, unlike Iceland where most homes are heated by geothermal energy, I believe. TastyCakes (talk) 22:20, 8 October 2009 (UTC)

Sorry, I re-read your question and see you wanted places in Europe... TastyCakes (talk) 22:21, 8 October 2009 (UTC)

Yeah, but purely with the view of visiting them and Europe is significantly closer that Quebec —Preceding unsigned comment added by 188.220.144.215 (talk) 22:34, 8 October 2009 (UTC)

99% of electricity in Norway is hydro (see Renewable energy in Norway); so much that they built the NorNed HVDC line to sell it to the Netherlands. -- Finlay McWalter • Talk 23:35, 8 October 2009 (UTC)

Yeah anywhere with loads of valleys and rivers can support most of their electrical needs with dams. British Columbia qualifies. Vranak (talk) 20:11, 9 October 2009 (UTC)

B-12 Deficiency

As I understand it, vegetarians require B-12 supplementation to avoid deficiency because B-12 is only available in meat. Now, I know that vegetarian diets have been around for thousands of years while B-12 supplements are a rather recent innovation. My question is: before the invention of B-12 supplements, were all vegetarians B-12 deficient? Or is there some other way of getting the required B-12? —Preceding unsigned comment added by 24.62.245.13 (talk) 23:42, 8 October 2009 (UTC)

Vitamin B12 is also available in things like eggs and milk, which vegetarians can eat. Perhaps you mean vegans. In any case, apparantly the body's stores of B12 can often go a long time without ruinning out. 89.242.154.74 (talk) 00:01, 9 October 2009 (UTC)

It's a very interesting question. Our own History of Vegetarianism article discusses the existence of what would now be described as Vegans in antiquity, with no mention of B12 issues. Someguy1221 (talk) 00:03, 9 October 2009 (UTC)

A balanced and varied vegetarian diet does not require any supplements. A vegan diet is rather more extreme and supplements or fortified foods are probably required. --Tango (talk) 00:09, 9 October 2009 (UTC)

There is B12 in milk - the vegetarians who have been around for thousands of years (like, for example, the ancient Greeks) were more than happy to consume dairy products. The only problem is with the vegans - but that particular group have really only been around since the early 1950's - which corresponds pretty closely to the time when Vitamin B12 became available and was known to be present in meat. So everything lines up rather neatly - vegetarians prior to the discovery of B12 didn't need it - vegans after the discovery of B12 had no problem getting it. The only thing I wonder about is how ancient greeks who were lactose-intolerant managed. It is often claimed that tolerance for lactose in adult humans is a fairly recently evolved trait that came along at about the same time as we developed the ability to farm domesticated dairy animals (sheep, goats, cows). That doesn't leave much time for the Greeks to have developed lactose tolerance...but I think the facts speak for themselves. SteveBaker (talk) 01:03, 9 October 2009 (UTC)

You're right. There were ancient vegetarians who shunned eggs, but there is no mention of avoiding dairy as well, as far as I can see. Someguy1221 (talk) 01:15, 9 October 2009 (UTC)

But as for the lactose intolerance, even the average lactose intolerant individual can still process a small amount of dairy, which may have been sufficient. Someguy1221 (talk) 01:17, 9 October 2009 (UTC)

The dairy thing is IMHO inadequate. There have been vegetarians in China and other East Asian countries for many years. While many of these may not have been strict, some may have been particularly I suspect some Buddhist vegetarianism. While these people may not have been opposed to the consumption of dairy I'm not convinced it was a common part of their diet for many of them be it from cows, goats, yaks, horses, buffalo or something else. Note that neither of our articles mentions milk or dairy products or lacto at all. In fact while modern day Indians vegetarians are lacto-vegetarians I wonder how common this was historically, e.g. Jain vegetarianism 7000 years ago. The fact that people were not opposed to drinking milk doesn't mean they regularly did. Of course it's difficult to know how strict people were. Nil Einne (talk) 11:49, 9 October 2009 (UTC)

B12 is not directly produced by the animals that humans eat, or whose milk and eggs are eaten by humans. B12 is not directly produced by any animals at all. For that matter, B12 isn't produced by any plants at all, either. B12 is unique among the vitamins, in that it is only produced by bacteria. See Vitamin B12#Synthesis.

B12 can be found pretty much anywhere that bacteria can be found, such as on your skin (in small amounts), or in dirt, or in feces. The feces of a human, even a vegan, contains far more B12 than a human needs. Unfortunately, the B12 in human feces is produced by bacteria that are lower in the digestive tract than the ilium, which is the primary absorbtion site for B12. It used to be possible to get B12 by drinking water from a source that's been contaminated with feces. As the drinking water article says, "Throughout most of the world, the most common contamination of raw water sources is from human sewage... In many parts of the world the only sources of water are from small streams often directly contaminated by sewage." But fecal contamination of drinking water has been eliminated in those parts of the world with sewage treatment plants, which of course are a relatively modern invention.

It also used to be possible to get B12 from the bacteria in dirt. But with modern plumbing (which has only been around for a couple thousand years), it's easy to wash all the dirt off of your vegetables. And any dirt on your skin gets washed off by frequent handwashing and daily bathing. However, bathing every day is a rather recent development. According to Bathing#Western history, bathing once a week was considered to be "frequent" bathing, until only about a century ago. On a personal note, my mom was only given the opportunitity to bath once a week when she was an exchange student in Germany, only about 60 years ago.

Due to all this modern hyper-cleanliness, the only reliable ultimate source of B12 for humans has become the bacteria that are found in the digestive tract, feces and environment of the animals used for food, or for vegans, the bacteria in the big vats of bacteria cultured for producing B12 supplements. Red Act (talk) 05:05, 9 October 2009 (UTC)