Wikipedia:Reference desk/Archives/Science/2013 September 16

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September 16

"Sea bamboo"

Hi, does anyone know what the stuff described as "sea bamboo" used for making jewellery (shown e.g. here or here) actually is? On Wikipedia, "sea bamboo" directs to Ecklonia maxima, described as a species of kelp, which doesn't seem a likely source for such a material. Could it possibly be Bamboo coral? 86.146.107.83 (talk) 01:10, 16 September 2013 (UTC)

A Google search tells me that "sea bamboo" is a type of Coral.217.158.236.14 (talk) 09:43, 16 September 2013 (UTC)

I have of course done Google searches. I found various references to something called "sea bamboo coral", but the information is a bit confusing. For example, this says that it is "not actual natural coral" but a "product of [a] marine plant". Also, this says that it is a shallow water coral, about which one would assume a reasonable amount is known if it is harvested in such quantities for jewellery, whereas Bamboo coral is apparently a deep-water coral about which "relatively little is known". Is it a different (related?) thing? Shouldn't it be mentioned at Bamboo coral? Yet again, this calls it "a kind of seawater plant fossil", which also does not sound like a coral (though I am aware that there are also plant cells also embedded in coral). 86.160.214.202 (talk) 11:49, 16 September 2013 (UTC)

The "Sea bamboo" you are referring to that is used for jewelry making is in fact a type of coral. This business http://www.beadaholic.co.nz/Beading_Information/Product+Information/Coral+and+Sea+Bamboo.html states that on the semi-gem market 99.9 % of gemstones used are some type of bamboo coral. This particular sea coral is named after its shape. The particular pictures of "sea bamboo" that you referenced had been synthetically dyed pink. Here is a picture of the before and after of synthetically dyed bamboo coral http://kamshin.cn/UpFiles/Article/2008103018274244653.jpg. According to http://www.fws.gov/International//animals/coral.html most coral that enters the United States are from Asian counties and the first picture you referenced stated that the jewelry was sourced from China. Also this research talks in depth about bamboo coral and states its scientific name (Keratoisidinae) http://cat.inist.fr/?aModele=afficheN&cpsidt=15444487 --Gusty7 (talk) 20:56, 20 September 2013 (UTC)

Has Titan got oil that is not a fossil fuel?

Recently, I had a discussion with someone who is a climate change “denier” and who asserted that crude oil on Earth was not just a fossil fuel, but most (or some) of it originated via simple chemical reactions. He pointed to the “oil” on Saturn’s moon Titan as proof of this*. As a consequence, there is no need to presume that “peal oil” is unavoidable, as it could well be manufactured. I thought that this was typical pseudo-science, but then looked at the WP article on Titan, and this WP one on the possible Colonisation of Titan https://en.wikipedia.org/wiki/Colonization_of_Titan

According to Cassini data from 2008, Titan has hundreds of times more liquid hydrocarbons than all the known oil and natural gas reserves on Earth. These hydrocarbons rain from the sky and collect in vast deposits that form lakes and dunes.[1] "Titan is just covered in carbon-bearing material—it’s a giant factory of organic chemicals," said Ralph Lorenz, who leads the study of Titan based on radar data from Cassini.

This made me take a step back from my pseudo-science accusations.

1. Is it really the case that Titan has oil?

2. Could you process it just like you do crude on Earth and stick it in a car’s engine?

3. Is it the case that oil can be produced in factories, and that there really is no “peak oil”?

4. If some / most Earthian oil is not fossil-based, how much IS fossil-based?

5. Are greenies hiding the truth about a potential sea of non-fossil oil because they want to see us go all wind and solar?

• Yes, he took me by the shoulder, we went out to the back of his yard, and he pointed upwards: "See that?" he said "That's your Titan, and can you make out that glistening patch over yonder? That's oil, gobdarn it, real Texas crude, YEEEHAH! YEEHAH! YEEHAH!" Myles325a (talk) 03:36, 16 September 2013 (UTC)

Here is a link to the NASA source of the text you quoted. Titan's Surface Organics Surpass Oil Reserves on Earth from 2008. ю 220 of ^Borg 03:55, 16 September 2013 (UTC)

1) "Liquid hydrocarbons" isn't necessarily the same as crude oil.

2) Possibly, but it would cost a billion dollars a gallon to bring it here from Titan.

3) Yes, see synthetic oil. However, it's way too expensive to use as fuel for cars, as is synthetic fuel. Also, both of those typically start from other fossil fuels, anyway.

4) I see no evidence of this process on Earth. The difference is that Earth has free oxygen, which tends to react with any hydrocarbons on the surface, to "burn" them, but slowly, over thousands of years (much faster with the aid of bacteria). This is why we don't have lakes of oil on Earth. Only oil underground, protected from this free oxygen, can survive for long here.

5) No. Even if some form of burnable hydrocarbons were produced from inorganic sources, they still wouldn't be produced at anything near the rate we are using them up.

So, it's not about a lack of any fuel, but a lack of cheap fuel. Sucking the raw ingredients out of the ground is the cheapest way to make fuel, and fuel prices will continue to go up as we have to dig deeper, use offshore platforms, etc., to get at the diminishing fuel supply. At some point, alternative fuels will be cheaper than starting from crude oil, and we will start to switch to them (this process has already started in some places). However, we may never get back to prices as low as we had when petroleum was plentiful. StuRat (talk) 04:35, 16 September 2013 (UTC)

Your friend is out of date. See Abiogenic petroleum origin. This theory stated that some (or most) of our oil reserves were created from non-living matter. It's now been all but discredited. The theory is kept alive by people with an axe to grind.

(Although, interestingly, that article says that a tiny fraction of simpler fossil fuels like natural gas may have an abiogenic origin. ) APL (talk) 05:19, 16 September 2013 (UTC)

All good points. I'd like to add that the first law of thermodynamics implies that even if we manufacture synthetic fuel (as e.g. Germany did in WW2 to produce fuel for tanks and aircraft), this is not an energy source, but only a means of energy storage and distribution. Indeed, the second law implies that we lose usable energy in the process. --Stephan Schulz (talk) 07:42, 16 September 2013 (UTC)

Technically true, but the energy source could be something that was going to be wasted otherwise, like farm waste or sewage we've exposed to genetically modified bacteria (to convert it to oil or fuel). Of course, this doesn't necessarily make it cheap, as you need to construct huge tanks for this fermentation, distill it to get the good stuff, deliver it, etc. StuRat (talk) 12:40, 16 September 2013 (UTC)

It's also worth pointing out that the problems that the world is facing are largely unrelated to "running out" of fossil fuel. The problem is the CO2 produced by consuming it. If we were to try to burn our remaining reserves of fossil fuels, we'd make the planet unlivable by humans long before we ran out of them. The (frankly, crazy) idea that new oil is being formed by some magical process or other is neither here nor there. A better heavenly body to look at is Venus - which ought to be a virtual twin of earth but because of a runaway greenhouse-effect is one of the more nasty hell-holes in our solar system!

Sadly, climate change (and "peak oil") deniers are becoming almost impossible to talk to in any rational manner because they are only too happy to simply refuse to see the data that's clearly available to all who care to open their eyes to it...they have to go into the same category as Apollo moon-landing deniers, Holocaust deniers, Homeopathists and flat-Earthers. SteveBaker (talk) 13:34, 16 September 2013 (UTC)

I am not sure about a couple of points of yours Steve. Imagine that we had already burned half the oil that is somehow available. That has provoked a temperature increase of 1.4 °F. What would happen if we burned the other half? Another 1.4 °F? Less than that? Or more than that? OK, global warming is happening, but maybe we can literally live with that. OsmanRF34 (talk) 16:53, 16 September 2013 (UTC)

Oil is one of the smaller parts of our fossil fuel reserves. It's important economically because it's cheap and easy to put in cars.

The big deal is coal and natural gas. APL (talk) 20:53, 16 September 2013 (UTC)

The world's oil reserves are hard to estimate. Our oil reserves articles says that we currently estimate 1,300 billion barrels of known reserves - plus 300 more in oil shales and sands, 510 more in the artcic...let's say 2,000 billion barrels in round numbers that could possibly be extracted. The world's annual oil consumption is around 80 million barrels per day - which gives us 68 years - assuming we consume neither more nor less oil than we are right now - and that we are clever enough to extract it economically from difficult places like oil shales and sands, bitumen deposits and from under the arctic ocean (which will get much easier when the North pole has melted!). I'd bet we'll find more reserves under the antarctic continent as the ice melts there too. However, that's just speculation.

Other fossil fuels will last much longer. There is about as much natural gas left as there is oil - and there is two and a half times as much coal.

Over the last 30 or 40 years, with about the same consumption rate we have now, we've added 0.8 degrees of warming (check out the first graph in Global warming) - if these effects were linear, then at present rate we would add around two more degrees of global warming over then next 68 years - making about 3 degrees total increase by the time the oil runs out.

But that makes two large (and unlikely) assumptions:

1. That burning X times as much oil as we already have will produce X times as much temperature increase.
2. That the current rate of oil consumption won't change until the day the last shovelful of oil sand is processed.

But we know for sure that there are several positive feedback effects that will cause the rate of temperature rise to increase as the world warms up:

• Melting the ice caps means that the earth reflects less sunlight out into space,
• As low lying areas are flooded by rising oceans, having a larger fraction of the earth covered with water means that we absorb heat faster.
• At some point, the deep ocean methane clathrates will melt, releasing an ungodly amount of methane will be released - and it's a far worse greenhouse gas than CO2.
• As permafrost melts, the peat bogs will start to decay, releasing more CO2.

etc, etc...so it's a little hard to predict how much worse than 3 degrees. Certainly we should expect more than a 3 degree increase if we continue as we are for another 68 years.

We also know that the oil won't run out that fast. Oil will get progressively harder to extract from these difficult places - the price will go up - so our reliance on gas and coal will likely increase - and the reserves of those are vastly bigger than the oil reserves. The oil won't actually "run out" (become economically infeasible to recover) until more like 150 years. If the other fossil fuels are used to fill the gap and our CO2 production rate continues unabated - we'd have a temperature increase more like 5 degrees by a straight "linear" assumption - and maybe much more than that if there are positive feedback effects - which would be pretty much "game over" for our civilisation.

For that reason, we have to cut back on all fossil fuel use LONG before we run out of oil. SteveBaker (talk) 14:11, 17 September 2013 (UTC)

Let's start from the basics. Hydrogen is the most common element in the universe. Exploding stars make lots of carbon, nitrogen, and oxygen. So planets like Earth and moons like Titan start out with a reducing atmosphere with lots of hydrocarbons, ammonia, and water (C, N, O each with as much H as possible). Now over time much of Earth's hydrogen has been lost to solar wind, so that there is more carbon dioxide and molecular nitrogen, etc.; but meanwhile the evolution of photosynthesis meant that plants could hoard carbon and hydrogen out of the atmosphere. The net result is that of all the original components of the atmosphere we are down to nitrogen, oxygen, some noble gas etc., and hydrocarbons seem scarce because everything wants them. Except where the plants' precious hoard is buried underground and cooked up chemically... the components of oil and of Titan's atmosphere are of course not exactly the same (for example the amount of ethane), but given the basics of what elements are available, there will inevitably be some similarities. Wnt (talk) 18:24, 16 September 2013 (UTC)

Atomic carbon in ISM

When was atomic carbon first detected in the interstellar medium? Plasmic Physics (talk) 07:31, 16 September 2013 (UTC)

Maybe 1980?[1] Thincat (talk) 08:13, 16 September 2013 (UTC)

Thanks. 1980 is too late, but the article gives Morton et al. (1973) as a possible date for earlier detection. Plasmic Physics (talk) 13:05, 16 September 2013 (UTC)

How can I work property rights for something ?

duplicate of question on humanities desk, see there. μηδείς (talk) 16:01, 16 September 2013 (UTC)

Are you believe general relativity theory ?why?

Are you believe general relativity theory ?why? — Preceding unsigned comment added by 37.238.39.250 (talk) 11:02, 16 September 2013 (UTC)

What does belief have to do with it? It's a fairly sound theory which has been confirmed by experiment. That is, things the theory tells us is true about the universe have matched observations. That's all that is needed for a sound theory. Belief has nothing to do with whether it is sound or not. --Jayron32 11:31, 16 September 2013 (UTC)

With any scientific theory, it has to pass four tests:

1. It has to explain all of the facts that whatever it replaces were able to explain. (It can)
2. It has to be compatible with whatever existing laws it does not replace. (It is)
3. And it has to produce predictions that can subsequently be tested. (It does)
4. It has to be falsifiable. (It is)

When all of those things are true - we generally accept the theory as "The Truth"...or at least "Our Best Idea Of What The Truth Is Right Now".

Our article Tests of general relativity lists many of the predictions of general relativity that have subsequently come true. One prediction of was that gravitational lensing sould occur. The first image at right here (taken by the Hubble space telescope) is of a gravitational lens (called an "Einstein Cross"). Another prediction was the existence of black holes - and evidence for the existence of one of those was found by the ESO's VLT from 2006,2010 and 2013 (second image at right). Many other tests have shown that this theory does indeed fit the facts of the observable universe.

Just like any other theory, it's possible for general relativity to eventually be proved incorrect - but to do so would require finding evidence outside the realms currently tested. The biggest issue remains that of how to reconcile general relativity with quantum theory. But consider that although Newton's laws of motion were eventually shown to be incorrect at high relative velocities and replaced by Special relativity - those laws are still useful and highly accurate approximations for most applications. If general relativity is proven wrong, it'll likely be in some extreme situation (such as at very small scales, where quantum theory rules) - and it's very possible that general relativity would continue to be used as an expression of the way the universe works at larger scales.

SteveBaker (talk) 13:23, 16 September 2013 (UTC)

I first saw the effects of going back in time like as De Ja vu, second , to add and subtract you need from any direction and therefore something missing — Preceding unsigned comment added by 81.218.91.170 (talk) 16:16, 16 September 2013 (UTC)

The only quibble I would have is with the statement "Our Best Idea Of What The Truth Is Right Now". It would be better stated as "Our Best Idea Right Now Of What The Truth Is". The Truth does not change. What changes is how much we know about The Truth. ←Baseball Bugs ^{What's up, Doc?} carrots→ 13:41, 16 September 2013 (UTC)

General relativity while very useful in cosmology, is known to be false as it is a classical theory. As SteveBaker points out above, it will break down at scales where quantum effects are important. But we don't have to wait for some experiment to falsify it, it is already falsified. Take e.g. the Hydrogen atom. A general relativistic description of the hydrogen atom is obviously in conflict with experiment. Count Iblis (talk)

Go on... Dauto (talk) 15:24, 16 September 2013 (UTC)

Neither General nor Special relativity says anything about going back in time. thx1138 (talk) 16:46, 16 September 2013 (UTC)

that say something about speed limit ? — Preceding unsigned comment added by 81.218.91.170 (talk) 17:14, 16 September 2013 (UTC)

The theory of special relativity says that nothing can travel faster than light - and that nothing that has mass while at rest can travel as fast as light. General relativity builds on special relativity...so yes, it does indeed say something about speed limits. SteveBaker (talk) 13:25, 17 September 2013 (UTC)

Woodward effect

Woodward effect seems to be too good to be true, because it promises us the way to create both reactionless drive and warp drive. So here is my questions.

1. Is this effect has been experimentally demonstrated? If yes, are they already exclude another possible force?
2. What implications could it bring to our space exploration?
3. Can we, at this stage, convince someone either a government, a private space company or kickstarter peoples to fund more research on this thing? If not, how?

140.0.229.26 (talk) 11:05, 16 September 2013 (UTC)

1) They claim it has been demonstrated, but the scientific community has yet to accept the results. Excluding other sources is the problem, as it was for cold fusion.

2) Huge implications, if it turns out to be true.

3) I suspect that most investors would want irrefutable proof that it can work before putting down major amounts of cash. StuRat (talk) 12:51, 16 September 2013 (UTC)

1. Is this effect has been experimentally demonstrated? - No. It says so right in the first paragraph of our article: "So far, no conclusive proof of the existence of this effect has yet been presented.".
2. What implications could it bring to our space exploration? - It's far too soon to speculate on that. Until it's been shown to actually work, we can't tell the engineering or economic cost of making one.
3. Can we, at this stage, convince someone either a government, a private space company or kickstarter peoples to fund more research on this thing? - The Woodward_effect#Results section of our article suggests that researches at a number of facilities (including on at NASA) have at least tried to replicate the experiment. Commercial space companies tend to stick to relatively proven technologies. They can't risk funds on something as blue-sky as this. Large-scale funding is unlikely until the existence of effect has either been clearly demonstrated - or the theory behind it has been widely accepted by the mainstream physics community.

Kickstarter would probably not accept this project. It would fall under their "Hardware and Product Design guidelines" (see http://www.kickstarter.com/help/guidelines) - which state "Projects must show details (photos, videos, sketches) of their progress so far, along with a prototype demonstrating the product's current functionality." - which would presumably be hard to achieve for a purely research project. However if you look at Comparison of crowd funding services, you'll see that several (eg Microryza, Petridish.org) are set up specifically to fund scientific research.

SteveBaker (talk) 13:02, 16 September 2013 (UTC)

To me the only way to conclusively proof that this is true is to slap this experimental thingy into a cubesat and hope for the best. However, no one wants to provide the funding for that, so its a chicken and the egg problem 140.0.229.26 (talk) 13:23, 16 September 2013 (UTC)

You are imagining that this thing is way more understood than it really is. Right now, the theory isn't anywhere remotely there - we don't know whether a practical drive would be the size of a grain of salt or twice the size of the moon - or anywhere in-between! The effect hasn't even been conclusively demonstrated yet. I would actually bet a good sized pile of money that it'll never work...it violates too many well-established scientific laws - and that's always a red-flag for any new device. What this needs is a white-board and a room full of physicists for six months...not physical machines...and certainly not physical machines that can be launched into the vacuum of space. SteveBaker (talk) 14:37, 16 September 2013 (UTC)

Seems like crackpot to me. Dauto (talk) 14:46, 16 September 2013 (UTC)

That's speculation, there is a line between crackpot and this sort of thing. OsmanRF34 (talk) 15:07, 16 September 2013 (UTC)

"Extraordinary claims require extraordinary proof" - and the idea that you can make a 'reactionless drive' is a highly extraordinary claim. So far, any "proof" has been exceedingly sketchy. So until we see some pretty darned extraordinary evidence, we should probably deploy occam's razor and ignore it. SteveBaker (talk) 16:20, 17 September 2013 (UTC)

Tritiated water

How much T₂O would someone have to ingest before the effects became noticeable? Double sharp (talk) 13:55, 16 September 2013 (UTC)

Acute radiologic effects, long-term radiologic effects, or isotopic effects? DMacks (talk) 13:57, 16 September 2013 (UTC)

Well, when does each "milestone" get reached? Double sharp (talk) 14:01, 16 September 2013 (UTC)

Titrated water has no well-established safe limits. It is generally believed that tritiated water is dangerous even in very small quantities. The information available does say that tritiated water has a biological half-life of 7-12 days (some factors that affect this include water consumption, physical activity and temperature).

Titrated water s naturally occurring in trace amounts, and so long as exposure remains low, the risk is minimal. As the amount of exposure goes up, so does the risk of cancer, just as with any radiation. A contamination of 1600 picocuries in groundwater is considered safe, as it only adds up to .3 millirem over a year. 100 millirems is considered safe for the public, 500 for pregnant nuclear power plant workers. Thus, groundwater contamination would have to reach around 2666666.6 picocuries, or 98666 Becquerel, would be required to affect a pregnant power plant worker.

[2] [3] [4] [5] M.Hayne 2.0 (talk) 19:32, 23 September 2013 (UTC)

Bug identification

spyder like kind of bug?

What kind of bug is this?

Last night it was in my kitchen’s floor, and was fast as hell

Iskánder Vigoa Pérez (talk) 14:17, 16 September 2013 (UTC)

My best guess is that this is a type of Pseudoscorpion. --Jayron32 14:20, 16 September 2013 (UTC)

Where in the world is the photo taken? What is the span of the longest legs? This info will help us give better answers/guesses. Anyway, I think most pseudoscorpions are much smaller than that critter looks. My best guess is a type of "tailless whip scorpion", i.e. a member of the Amblypygi. SemanticMantis (talk) 15:02, 16 September 2013 (UTC)

i guess it was 4" or so... and was very fast

the foto was taken in Cuba, Artemisa — Preceding unsigned comment added by Iskander HFC (talk • contribs) 15:08, 16 September 2013 (UTC)

Thanks, that helps! I'm now pretty sure it is indeed a tailless whip scorpion.

Describing my process, in case anyone is interested:

1. Front "mouth parts" are just wrong for spiders, they seem to be pedipalps, not spider mandibles or fangs.
2. It is scorpion-like, but pseudoscorpions are too small (and tend to have more elongated body profiles), and Solifugae have other, stranger mouths.
3. Trying to guess common descriptions, I googled combinations of /flat crab scorpion/.
4. That led me to this nice page dedicated to tailless whip scorpions (with cute baby pics!) [6]
5. Back to WP, tailless whip scorpion has the right redirect, and I confirmed a few key traits: a)flattened body, solid carapace, with segmented abdomen b) elongated sensory legs, c) pedipalps used as prey catchers.

Hope that clarifies/ helps others in their weird critter ID process. SemanticMantis (talk) 15:19, 16 September 2013 (UTC)

• Yes, it's a whip spider. Pseudoscorpions are very small; I found one crawling on my mother after she was gardening, and, unfortunately, killed it thinking it was a tick. μηδείς (talk) 15:52, 16 September 2013 (UTC)

In the way it moved resembled more a cockroach than a scorpion or a spider

Certainly it isn’t any of the ones pictured in the articles… maybe similar to the tailless whip spiders

Iskánder Vigoa Pérez (talk) 16:47, 16 September 2013 (UTC)

Yes, they are fast, and might move sideways. Your pic looks a lot like this one [7], which is Phrynus_marginemaculatus. SemanticMantis (talk) 16:56, 16 September 2013 (UTC)

It's Amblypygi for certain, but they all look very similar. Looie496 (talk) 16:59, 16 September 2013 (UTC)

Mycoremediation of Sarin

In his 2005 book How Mushrooms Can Help Save the World; Mycologist Paul Stamets states certain classified species of mushrooms can bio-remediate Sarin; a statement he made previously in the magazine Whole Earth in 1999. Would this information be appropriate to add to the article on Sarin? Paul Stamets is the one who coined the term mycoremediation, and the research is difficult for civilian scientists to peer review as it is now classified. CensoredScribe (talk) 16:13, 16 September 2013 (UTC)

Whether you can include it into the Sarin article depends on what fact you're trying to provide a reliable source for. If it's to say "Mushrooms can bio-remediate Sarin" - then probably not because (as you say) this is a one-off report with no accessible peer review. On the other hand, if you wanted to say "Research is underway to see whether mushrooms can bio-remediate Sarin" then it's a good reference for that fact. SteveBaker (talk) 19:06, 17 September 2013 (UTC),

Thanks, but unfortunately it won't be allowed to be on the page for Sarin even the way you described it, because Wikipedia likely is censored.

No, it's not censored. Read: WP:NOTCENSORED. It would be impossible to censor Wikipedia without everyone knowing about it because there are edit histories - and many eyes on each article. You'd have to lock up maybe 100,000 people to effectively censor it - and I think someone might notice if you did that. This is one conspiracy theory that absolutely doesn't hold water! SteveBaker (talk) 21:13, 18 September 2013 (UTC)

how to isolate the Acetylsalicylic acid from the white willow (salix)?

If I have a little branch of white willow and I want to isolate the Acetylsalicylic acid from the tree, how can I do it? or how can I take it off from the willow without destroy it? (in example to boil it in water or something) 95.35.250.74 (talk) 19:35, 16 September 2013 (UTC)

As far as I know, willow bark has no (well, maybe almost no) acetylsalicylic acid per se. It has salicyclic acid, without the acetyl group.

I remain somewhat confused on this point. Our aspirin page claims, or has claimed, that aspirin works by irreversibly acetylating COX, which salicylic acid obviously can't do (no acetyl group). So is the similar (though less potent) action of natural salicylates just a coincidence? I've never gotten the straight story on this. --Trovatore (talk) 19:40, 16 September 2013 (UTC)

Methyl salicylate is also a known pain reliever, and claims are made in that article (with refs) that the body does metabolize it and other salicylates into Acetylsalicylic acid. The Salicylic acid article itself also notes its pain relieving and fever reducing properties. --Jayron32 20:06, 16 September 2013 (UTC)

"Metabolize" is an odd word to use in this context — apparently you mean the body acetylates the salicylates? Why does it do that? Is it an instance of a general detoxification strategy or something? --Trovatore (talk) 20:33, 16 September 2013 (UTC)

I don't see any claim about acetylation in the methyl salicylate article. To be clear, plain salicylic acid was discovered first. Then people realized it was burning holes in their stomachs, so they figured they could neutralize it a bit by acetylation (I think - the chemistry beliefs of the time were confused, but preparations like 'Bufferin' reflect the belief that the acid was the problem). The aspirin really did cause less stomach upset, though the protection given by the acetyl ester is inferior to that of natural glycoconjugates that had been used for at least five millennia before the marvels of modern chemistry... Anyway, getting back to the point, anything on that phenolic OH comes off, sooner or later, and the same is true for the willow salicylates. You can study them by something like this (grind up in water:methanol:chloroform, purify/assay by HPLC) - however, if your intent were just isolate a preparation for use, any complex lab work should be avoided, since the willow contains other active compounds besides salicylate [8] and using a standard herbal preparation method listed in a reputable pharmacopoeia, in accordance with local regulations, is just safer overall. Wnt (talk) 21:03, 16 September 2013 (UTC)

Oh, and metabolize would have been the right word, as it encompasses both anabolism and catabolism. Wnt (talk) 21:05, 16 September 2013 (UTC)

Well, that may have been what people thought they were doing by acetylation. However, if aspirin's primary mode of action is that it acetylates COX, then it would seem that the actual effect of acetylating salicylic acid is that it provides an acetyl group that can then be transferred to COX. Unless as Jayron says the salicylates get acetylated in the body anyway? But I don't see that in the link he gave either. --Trovatore (talk) 21:09, 16 September 2013 (UTC)

Hehe, biology likes to play tricks on scientists! Aspirin will indeed inhibit COX in vitro by acetylating it. But when consumed, aspirin is quickly converted back to salicylate. The salicylate, it turns out, somehow manages to prevent transcription of COX enzymes by some other means. [9] (I wonder if it is mimicking one or more endogenous compounds which have had the time to evolve a complex regulatory biology) Wnt (talk) 01:01, 17 September 2013 (UTC)

Hmm, well, our articles on aspirin and mechanism of action of aspirin still claim that it works by acetylation. Not my field; I couldn't say. --Trovatore (talk) 01:08, 17 September 2013 (UTC)

That proof "negative time negative equal positive" is wrong|What would happen if proved wrong proof ?

I have a proof on this but I know proof "negative times negative equal positive"

this is

according to proof wrong

-(-a)=a

-(-a)+0

-a+a=0

-(-a)+(-a+a)

-(-a)+(-a)+(+a)

-(-a)+(-a)=0

0+(+a)

=a or +(+a)

this is wrong ObaidNgers (talk) 20:01, 16 September 2013 (UTC)

You may be better off asking this at the Mathematics desk. --Jayron32 20:03, 16 September 2013 (UTC)

"doesn't make any sense" may be more accurate than "wrong". 86.160.214.202 (talk) 20:55, 16 September 2013 (UTC)

Nah, the first line is a valid statement; the second equality contains an error; the third equality is valid but is just an expansion and proves nothing byond what is already given. 1.122.109.132 (talk) 00:27, 17 September 2013 (UTC)

I don't understand the "proof" above - there are missing equals signs and who-knows-what else.

It's very hard to construct a "proof" of this because the very rules of algebra assume that you can say things like:

1. a = a
2. -a = -a
3. --a = a
4. -(-a) = a
5. -1.-a = a

Which "proves" that if a is a positive number than (-1).(-a) is also positive - so negative times negative must be positive. But all that really demonstrates is that the algebraic operation of converting --a into (-1.-a) is legal - which makes the assumption that a negative sign implies a multiplication by -1. But that's only true if negative-times-negative makes positive and that --a = +a ...all of which would be untrue if negative-times-negative isn't positive.

So it's hard to "prove" that a fundamental mathematical operator like 'x' works that way.

In algebraic systems where the concept of multiplication isn't commutative (such as when multiplying matrices) the rules are different.

The consequences of this rule being untrue in basic arithmetic would be a paradox - and the Principle of explosion says that if you assert a falsehood then everything can be proven to be both true and false. If you can show that if (-1 x -1) = -1 then you can use that to prove that Santa Claus exists. (No, really! The proof is in Principle of explosion!)

SteveBaker (talk) 16:06, 17 September 2013 (UTC)

You seem to be implying that Santa Claus doesn't exist. Dauto (talk) 18:14, 17 September 2013 (UTC)

Oh, not at all! I'm just saying that if you can prove any contradiction, then Santa Claus must exist. His actual non-existence is clearly unfalsifiable. SteveBaker (talk) 18:55, 17 September 2013 (UTC)

And you can also prove from that that Santa Claus doesn't exist... Double sharp (talk) 10:50, 18 September 2013 (UTC)

Don't worry - you can also prove that it doesn't matter that he both exists and doesn't exist. Katie R (talk) 12:12, 18 September 2013 (UTC)

Mountains in Norway

Why are there mountains in Norway when there is no tectonic plate edges or volcanoes near? — Preceding unsigned comment added by 88.193.85.124 (talk) 20:19, 16 September 2013 (UTC)

I started at Mountain ranges of Norway, and then went to Caledonian orogeny and Geology of Norway.

Short answer: there used to be plate boundaries there. SemanticMantis (talk) 20:35, 16 September 2013 (UTC)

And surely glaciation must have played a role, by scraping the valleys deeper, thus making the mountains taller, relative to the valley/fjord floors. StuRat (talk) 06:47, 17 September 2013 (UTC)

Much of Scandinavia was close to sea level at the end of the Cretaceous. Since the Late Paleocene there has been dramatic uplift, modified more recently by glacial erosion and unloading. The cause of this uplift is still not well understood, although it may be to do with the peripheral effects of the opening of the North Atlantic at the end of the Paleocene (and therefore a plate boundary related process). This is discussed here, but I'll try to find some more references this evening. Mikenorton (talk) 07:08, 17 September 2013 (UTC)

According to this ref the uplift affects far more than just Norway, including all the borderlands to the North Atlantic from southern Greenland to Ireland. The uplift was accompanied by anomalous subsidence in all of the basinal areas, including the North Sea, the Norwegian Sea, the Rockall Basin, the Porcupine Basin and the Faeroe-Shetland Basin. The suggested causes listed in that paper include: magmatic underplating, thermally driven dynamic uplift, convection driven, asthenospheric diapirism, lower lithosphere delamination, intraplate compression and isostatic rebound. The paper suggests that the first pulse of uplift/subsidence in the late Paleocene—-Eocene was related to break-up between Europe and Greenland. Localised and episodic uplift in the Oligo-Miocene were possibly related to the overall compressional stress state and changes in spreading rates and directions in the North Atlantic. It offers no explanation for the (possibly ongoing) Plio-Pleistocene uplift that affects most land areas. Mikenorton (talk) 20:28, 17 September 2013 (UTC)

Variable power supply plug

I have one of these switching power supply plugs. What is likely to happen if the resistance of the load is insufficient to limit the current to less than 1A? The plug has a CE mark, so presumably meets minimum requirements for safety in the UK. Does that mean a mechanism inside the plug stops the current from going past 1A and limits the voltage accordingly? — Preceding unsigned comment added by 78.150.23.174 (talk) 21:14, 16 September 2013 (UTC)

Yes there is. 24.23.196.85 (talk) 23:23, 16 September 2013 (UTC)

While the voltage may drop on heavy load, it may or may not drop sufficient to limit the current to one amp. The manufacturer does not claim or indicate that any overload protection circuit is inside. As with plug packs in general, you should assume that exceeding one amp will overload it and damage it. Note that such damage may or may not occur immediately, it may require a long period of operation or may only occur at high ambient temperatures. However, safety aspects, such as fire or electric shock hazards, arising as a consequence of overload damage are should be unlikely. I say "should be", as CE marking is a self-certifying scheme and thus subject to a certain amount of abuse, ignorance, and plain oversight by manufacturers, particularly the less well known far east manufacturers. 1.122.109.132 (talk) 00:17, 17 September 2013 (UTC)

Okay, thanks. If I'm interested in electronics as a hobby, at what point would I need to a power supply more like this one? In what ways would I be limited by using that plug in lieu of a regulated supply? (maybe I won't cross that threshold and therefore don't need the regulated supply) 78.150.23.174 (talk) 03:54, 17 September 2013 (UTC)

The power supply you linked is a basic labaortory unit. As to what stage you will need to consider a lab supply is just about impossible to answer. There is such an enormous range of things in electronics you can do, and such an enormous range of ability that beginning hobbyists have, and how far they'll go. A lot of hobby projects published in magazines and elsewhere are designed to use plug-packs ("wall warts" in America) or batteries, because it simplifies things and completely removes any concerns about electric shock hazards and fire safety.

I became interested in electronics at age 9, and by 12 years of age I had succesfully built a vast number of radios, walkie-talkies, burglar alarms, and gadgets like soil moisture meters without ever thinking of powering them from anything other than a 9 volt battery. When I moved on to building things like high power stereo systems, I had enough knowlege to build my own power supplies in complete safety - part of the fun. Probably the best advice I can give, without a long discussion with you to find out what you expect to do in your new hobby, is this: Don't buy a power supply of any type beyond a simple plug-pack until you know you need it, you understand why you need it, and the cost is simply not an issue for you. Or, to put it in another way, when you definitely need a lab supply, you'll know - you won't have to ask.

However, the posession of a laboratory variable power supply, together with a range of instruments (multimeters, oscilloscopes, signal generators) will assist you in doing a range of basic and fundamental experiments that will help advance your electronics theory knowlege, should you be that way inclined. One can choose two ways to go early in a hobby, especially in analogue electronics as distinct from microcomputers. You can go for developing a good fundamental knowlege of theory (like an engineer), or you can go for building things out of kits or magazines without really understanding how they work (somewhat like a technician), and why the designer did things a certain way. Both paths can be very satifying. The first path requires a greater commitment in time and money for a given quantity of things to impress non-technical friends.

1.122.41.205 (talk) 05:24, 17 September 2013 (UTC)

1.122.41.205 what is this: "You can go for developing a good fundamental knowlege of theory (like an engineer), or you can go for building things out of kits or magazines without really understanding how they work (somewhat like a technician)," Believe me there are many electronics technicians who have a "good fundamental knowlege(sic) of theory". Of course it depends on the particular course/s you do. I trained in electronics and got, AFAIK, rather good knowledge of semi-conductor, RF, Navigational Aid and other electronic theory. I received specialist practical & theoretical electronics training in the Aeronautical field (ground based) as well as a formal TAFE Certificate (not degree) in Electronics Engineering. I was fortunate to get 4+ years full-time theory & practical training with field experience, which is probably unavailable (or too expensive) today. Of course the exact meaning of 'technician' may well vary widely between countries(or even industries) and your statement would perhaps apply more to an Electronic Tradesman. Those would be the lowest level of semi-/skilled worker, then Technician, maybe Engineering Associate, then 'Full' Engineer. I often see the term "technician' applied to what used to be called a Car mechanic, though the skills are likely rather higher now days, with computer black boxes common in cars. The term 'Engineer' is often similarly misused. --220 of ^Borg 18:27, 17 September 2013 (UTC)

As the saying goes, oils ain't oils. You are quite right - there are technicians and there are technicians. And there are engineers and there are engineers. I know people who have only trade certificate who can easily outperform the average degreed engineer. And I know engineers with Ph.D's who know jack shit in practical application. Both terms "technician" and "engineer" are frequently misused. I once interviewed a chap who applied for the position of Assistant Engineer at a broadcast TV transmitter site. He had a Bachelor Degree in Electronics. I asked him what the Channel 2 frequency was. He answered "About 2 MHz". I asked him "Roughly how many turns would there be on a 100 VA 50 Hz power transformer?" He said "a few hundred". I then asked "How would a 100 watt transformer operating at 50 MHz differ?" He said "a few less turns" and could not think of anything else. Well, there was no way I would give him a job anyway. A shopping centre near me has a little shop that "repairs" cellphones. They have a big sign: "Talk to our technician". Their "technician" is a 16 year old kid with no qualifications at all and who knows nothing more than how to wield a screw driver, change batteries and phone skins, what a simcard does, and who to call to get lost PIN numbers. But none of this changes what I said above - there ARE two ways to approach electronics as a hobby - acquire theory thru experiment and reading, or just build things from kits. There's nothing wrong with either approach. Horses for courses. In any case, the first approach will give you some practical skill as well as the theory, and the kit building approach will give you some "how stuff works" knowlege as well as the practical skill. 120.145.80.207 (talk) 04:54, 18 September 2013 (UTC)

Chuckle. :-D 120.145.80.207, you are very obviously 'in the industry'. "I know people who have only trade certificate who can easily outperform the average degreed engineer. And I know engineers with Ph.D's who know jack shit in practical application." How very true! I would think that a combination of kit building (to start) and then theory is the way to go. I would think that most hobbyists would start with the building of pre-packaged kits (Like Heathkit or RadioShack Corporation in the USA & Dick Smith and Jaycar in Australia. Unfortunately Dick Smith no longer sells kits, components or test equipmment (and many other similar shops have closed over the last 10-20 years). I never cared too much for the theory (even though the kits often had detailed technical explanations) until I got some formal training, I just enjoyed making things that did stuff! However when the kits didn't 'do stuff', then the reading and theory came in. As well as the very practical 'look for blown /burnt out or reversed components'(or 'Magic smoke'), bad joints and incorrect wiring. Quite common when you are building from scratch , and I still have devices I made years ago that I can't get working! (So much for the theory!) Hm, I just remembered that my 'experiment and reading phase' was fairly early. I often mucked around with batteries/ magnets and such at school (primary?), then got into kits at secondary school. :-) ∝ 220 of ^Borg 11:03, 20 September 2013 (UTC)

Horses for courses, as I said. I never built from kits, though I did as a child start some projects with circuits out of magazines, after I got a package called "Philips EE Engineer". This was an early 1960's marvellous collection of parts sufficient to build a 3-transistor radio, a simple organ, and about 20 other things, a board with a grid of several hundred holes punched in it, and a quantity of spring devices that go in the holes and enable you to connect parts up without soldering, so you can re-use them. Each circuit was described in the very well written manual. I was more into theory, "why is it so", and designing my own circuits. This meant that at first I built a lot of stuff that didn't work too well, but I learnt perseverance and the ability to anticipate why a circuit might not work, and to look at every angle. It's stood me in good stead ever since. But not a path for everyone. 124.182.5.71 (talk) 00:43, 21 September 2013 (UTC)

@ 78.150.23.174, I would say that you might well never require a power supply like the one whose picture you linked. Though it might be a very nice piece of test equipment to have, it may well be quite expensive, (If you can link to more information about it like price, please do so) You could also build your own variable lab type power supply from a kit. A multimeter is a must. Though I have never acquired a Cathode-ray oscilloscope (CRO), these are much cheaper now than 30 years ago in LCD type display and can do most/all that a multimeter can do as well.
A good electronic type soldering iron is probably the first thing you will need as a hobbyist, plus basic tool like side-cutting pliers, screwdrivers etc.--220 of ^Borg 18:27, 17 September 2013 (UTC)

Relationship between knowing how to touch-type and electronic test scores?

Is there a relationship or correlation between knowing how to touch-type (that is, typing without looking at the keyboard) and doing an online exam? I predict that people who know how to touch-type have more time spending on the material than they do typing; therefore, they may receive better scores on tests. Though, it doesn't hurt to learn what the research says. 164.107.103.68 (talk) 21:42, 16 September 2013 (UTC)

I'm not aware of any research, but offer the following factors that will reduce or eliminate any linkage: Firstly, online exams should be designed so that bulk typing of text is not required. In many cases, exams are multi-choice, so intead of ticking boxes on paper, you are clicking on screen boxes with a mouse. If the exam is an engineering or science subject, touch typing as taught by secretarial schools won't help much, as they teach what works well with business letters, not science/engineering. Touch typing relies on a rhythm to get speed that sceince and engineering typing tends to stuff up. In exams, you will likely be doing a lot of mousing, for which touch typing has no relavence. Mousing stuffs up touch typing rhythm. Lastly, I found that after using PC's for about 5 years, without any typing training, that while I only graduated from "two-fingered hunt & peck" typing to actually using about four fingers, on ordinary business typing I can keep up with almost all "office girl" types who have been trained in touch typing. On on typing scientific bulk text, I run the pants off them, on both speed and accuracy. We use a lot of multi-syllable specialised terms in science and engineering and they can't cope with it. University academics and doctors employ specialist typists for this reason and pay them more money than the ordinary office girl gets. But even they can't go that much faster, though they are considerably better in accuracy. My secretary/PA is as good a worker as any in industry, and on ordinary business letters goes very quick. But watching her type up a service manual is very painfull. On sentences such as "Remove the widget cover by undoing the four screws and tilting to the left." she goes like the clappers and does a perfect job. But on stuff like "Using the HP 8556 spectrum analyser, adjust the bandpass filter inductor slugs to peak the amplitude response in order to the frequencies listed in Table 6.10", she goes almost letter by letter slowly and makes lots of mistakes. 1.122.109.132 (talk) 01:28, 17 September 2013 (UTC)

I expect that people with touch-typing skills are more likely to be computer-literate, as well, so might do better on any exam where computer literacy is either being tested intentionally, or unintentionally. StuRat (talk) 06:45, 17 September 2013 (UTC)

You can also use voice to text facilities of your I-phone or PC. If it is fine tuned to recognize your voice and has a suitable library for common words for the particular subject matter, it works quite well. Count Iblis (talk) 11:46, 17 September 2013 (UTC)

Aren't most online tests of the multiple-choice variety? Touch-typing won't really help when it's largely mouse-clicks. ←Baseball Bugs ^{What's up, Doc?} carrots→ 12:35, 17 September 2013 (UTC)

Also far easier (cheaper) to mark. Probably totally automatic, whereas typed answers would likely require a human to assess them. ←220 of ^Borg 18:34, 17 September 2013 (UTC)→

Actually, nothing new about that. I remember marking multi-choice exams 40 years ago. We originally used templates, light cardboard sheets with holes cut in them where the ticks should be. We put the template over each exam paper and just counted the number of ticks visible through the holes. 4 templates and 4 counts are needed for each exam paper, as some choices add marks and some choices subtract marks, in order to prevent students getting a pass by narrowing each question down to two choices by rejecting the silly choices, and then picking the remaining two possibilities randomly. Even so, one soon acquired a skill and easily marked each paper in seconds. Then, the college introduced machine marking. Students were told to answer using a heavy black pencil, supplied to them. Their papers were then sent to a computer company (no local computers or PC's back then) who scanned them optically, and sent back the computer compiled results. 120.145.80.207 (talk) 04:32, 18 September 2013 (UTC)