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March 14

Is it possible to cause a prolonged temperature increase (eben a small one) in the skull just through mental activity?

Is it possible to increase the temperature of the skull, even by only a slight amount, just through assiduous mental activity? If so, what kind of mental activity is appropriate that I could do to show this effect? (Note: I'm the poster who asked about boiling water above) 80.187.97.42 (talk) 00:32, 14 March 2010 (UTC)

A metabolic PET scan can show increased glucose oxidation occurring in parts of the brain where mental activity is occurring, but actual temperature increases are too small and thermal conductivity of human tissue too poor to measure any differences overlying the scalp. (And yes, it was obvious it was the same questioner.) alteripse (talk) 05:14, 14 March 2010 (UTC)

Contrary to intuition and many claims in the popular literature, the increase in brain metabolism as a result of intense mental activity is actually pretty small, just a few percentage points. Our article Brain#Brain energy consumption gives a pointer to the scientific literature on this topic. A lot more heat is actually generated by the muscle-tensing that people tend to do when they are thinking very hard -- this can easily give rise to a misperception that it is the thinking itself that consumes energy. Looie496 (talk) 17:26, 14 March 2010 (UTC)

Certainly there is some change in the energy consumed by the brain when doing more calculations than in a resting state. That energy has to go someplace - and that someplace is heat. But the difference between the rest state and the working state is small and the energy consumed is small - so the temperature increase is undoubtedly there - but very, very tiny. SteveBaker (talk) 17:29, 14 March 2010 (UTC)

But, you have to define "resting state" - and since it is not clear what level of "rest" corresponds to "idle thinking", we can't really say with certainty that (for example) arithmetic is "more brain work" than staring at a blank wall. In other words, the biological version of the NOOP instruction might be just as energy-intensive as the biological version of the XOR. As an example, there are many digital computers which do this intentionally (to provide for extremely deterministic power consumption, for example). I see no reason to assume that the brain needs more energy when undergoing "heavy thinking" (unless somebody has a scientific source to the contrary). Nimur (talk) 17:15, 15 March 2010 (UTC)

Perhaps extreme high levels of mental activity could cause increased blood flow to the brain, thereby raising the temperature of the brain? But I'm not an expert on this. ~AH1^(TCU) 02:02, 15 March 2010 (UTC)

I'd expect increased blood flow would cool your brain down. I'm pretty sure your body uses it for coolant. This would probably be countered out by burning the extra oxygen and sugar the blood brings. So, even less of an effect. — DanielLC 04:09, 15 March 2010 (UTC)

The answer to your first question is a qualified yes, but it is not as straightforward as you may imagine.
Neuronal activity does increase local metabolism, consuming oxygen, and producing heat, which tends to heat the local tissue. However the body responds by increasing the blood supply to the region of the brain that is being used, and the effect of this usually overwhelms the direct metabolic effect. Paradoxically, the oxygenation level of the active areas of the brain increases, and the temperature (typically) falls a few tenths of a degree centigrade. However the temperature change shows considerable inter-subject variability depending upon for example, the physical activities the subject is engaged in, and their environment, since these affect the instantaneous blood and cranial temperatures. You can read more about the subject in the following articles, and the references they contain:

• Coupling between changes in human brain temperature and oxidative metabolism during prolonged visual stimulation, PNAS, 2000
• Theoretical model of temperature regulation in the brain during changes in functional activity, PNAS, 2006

These references will also give you an idea of the techniques used to measure the temperature in areas of the brain in vivo.
Typical mental activities that are used in such studies are visual simulation (fancy way, of saying show some moving pictures), or simple finger tapping, which engage the visual cortex and motor areas of the brain respectively. Abecedare (talk) 09:03, 15 March 2010 (UTC)

Clockwise and counterclockwise galactic spirals

I've noticed whenever I deliver rolled up papers that they are either rolled up clockwise or counterclockwise, depending upon the end of the paper I am looking at. On the other hand whenever I read a astronomy article in order to improve my brain I only seem to get more confused since the articles say that Galactic spirals only rotate in a clockwise direction. However, when you view the Galaxy from the other side, like looking at the other end of the rolled up papers, the Galaxy is spiraling counterclockwise instead of clockwise. Should I stop reading astronomy articles and just go with what I know? 71.100.11.118 (talk) 02:07, 14 March 2010 (UTC)

A spiral galaxy will look clockwise from one direction and anti-clockwise from the other, just like any other spiral. Can you give an example of one of the astronomy articles you have been reading that say otherwise? Perhaps you are misunderstanding them (either that, or you need to read better astronomy articles - we can help you there, too!). --Tango (talk) 03:25, 14 March 2010 (UTC)

The latest article (2002) I've read makes a comparison of the rotation of the central bulge and the rotation of the spiral arms as being in opposite directions. What is surprising and confusing to me is that I can find no characteristic of classification which is based on the 3-axis orientation of the Galaxies and in conjunction on clockwise or counterclockwise rotation. 71.100.11.118 (talk) 04:09, 14 March 2010 (UTC)

I can't comment on the galaxy described in that article, having not researched it, but that article doesn't say anything about galaxies being rolled up the same way from both sides... --Tango (talk) 05:09, 14 March 2010 (UTC)

The article says nothing to make clear that the opposite directions of rotation will be reversed when looking at the Galaxy from the other side. 71.100.11.118 (talk) 07:09, 14 March 2010 (UTC)

Why would the article make that clear when it is obvious anyway? --Tango (talk) 08:38, 14 March 2010 (UTC)

I think perhaps the OP is asking why we would choose to view it from one side, and not the other? What justification do we have for that? I don't know the answer, but this seems to be what they're after. Vimescarrot (talk) 09:58, 14 March 2010 (UTC)

We have no choice - galaxies are a little far away to go around behind them to get a photo. --Tango (talk) 10:30, 14 March 2010 (UTC)

There actually is a very good choice which would fix the problem. First we need a reference point and that point can be the Earth. Next we need a system which utilizes that reference and that system is already in existence and well known. That system is Spherical coordinate system. What we need when talking about any Galaxy or about some aspect of its orientation is to speak first in terms of Spherical coordinate system. I would think we could draw a line between the Earth and the Galaxy and let that line represent the coordinates of two perpendicular planes and then provide the coordinates of the axis of rotation in either the clockwise or the counterclockwise direction 'so long as it were named. Perhaps we could call the clockwise side the North side and the counterclockwise side the South side. In fact, maybe someone has already thought of this and we can adapt, refer to or use the system they have designed. 71.100.11.118 (talk) 12:08, 14 March 2010 (UTC)

The galactic coordinate system and supergalactic coordinate system are very similar to what you describe and could easily be used to define north and south sides of spiral galaxies (and, for all I know, maybe already are). --Tango (talk) 12:49, 14 March 2010 (UTC)

Very similar. Although the Earth's Geographic coordinate system is more dynamic in terms of looking at Galaxies than our Sun or the Milky Way using it as a reference point instead would allow it to be more directly or easily included in time dependent observation chart object data. Of course such a system can also be easily duplicated for any reference point. 71.100.11.118 (talk) 03:51, 15 March 2010 (UTC)

In fact it might do very well to establish such a system for every Galaxy and then use the spherical coordinates to identify the locations of all other heavenly bodies. With such information provided to a neural network model... but then I allow my imagination to go too far! 71.100.11.118 (talk) 10:38, 15 March 2010 (UTC)

Clockwise and anti-clockwise rotation as seen from Earth has been counted. See Galaxy Zoo#Progress. PrimeHunter (talk) 03:49, 14 March 2010 (UTC)

Brain acceleration?

I was staring at clock, and noticed that when I first look at it, it seems a second hand stays there for a while (more than a second), and only then it goes on at a normal pace. Same thing happens with digital clocks as well. Why does it happen? Does the brain accelerate itself in order to analyze the information given by clock, so it seems time slows down for a while? 195.238.106.80 (talk) 02:19, 14 March 2010 (UTC)

Interesting. I have never noticed this myself, but a bit of Googling shows that it is a known phenomenon, although the cause is not clearly understood. Here is a review from last year that discusses the effect, along with other temporal illusions. Looie496 (talk) 03:08, 14 March 2010 (UTC)

Just to add a bit of info, the review suggests that this is a consequence of the suppression of visual perception that occurs during saccadic eye movements -- when you move your eyes rapidly from one place to another, your visual system basically switches off during the movement, but your time perception is warped for a short time before and afterward so that you don't perceive any gap -- in effect you perceive the eye movement to occur instantaneously. Looie496 (talk) 03:14, 14 March 2010 (UTC)

It's an amazing thing that our brains can create a seemingly seamless perception of the world given that the information provided by the senses have so many gaps and delays and mismatches. Dauto (talk) 03:59, 14 March 2010 (UTC)

There is a really interesting article in this month's PopSci about this kind of stuff, entitled "How Time Flies". It is related to the brain's perception of time dilation under different circumstances and, while nothing is conclusive at this point, it elaborates on some pretty plausible theories. However, since it is the current issue, they won't have it posted on their web site for another couple weeks. —Akrabbim^talk 04:08, 14 March 2010 (UTC)

This article in New Scientist is good, and discusses the effect extensively: http://www.newscientist.com/article/mg20427311.300-timewarp-how-your-brain-creates-the-fourth-dimension.html --99.237.234.104 (talk) 04:57, 14 March 2010 (UTC)

I've experienced this too and have always been curious as to why it is. I've always just assumed that it's some sort of processing delay but never had a true understanding of why it happened. The theory regarding the movement of your eyes and the switching off of your visual system is pretty interesting.

That part is more than just a theoretical thing - some work I did in flight simulation actually relied upon it.

Back when computer graphics systems were hideously expensive it might cost you a million dollars to build a system that was less capable by far than a $100 graphics card of today. So making a large dome around the pilot and projecting computer graphics everywhere inside of it would have been prohibitively expensive. Instead, we built a system that measured the position of your head and eyes using a motion-sensitive helmet with an infrared camera that looked into your eyes and figured out where the 'blind spot' was on your retina - and from that, calculate exactly where your head and eyes were pointing. Then, we used a motorized projection system that mechanically moved a mirror and directed the graphics display to draw only in the region you were actually looking. That way we only had to draw detailed graphics in the area that actually mattered - and we filled in the 'background' with a very crude representation of sky and horizon brightnesses to keep your peripheral vision happy.

The problem with that was that the system took time to figure out how your gaze was moving and get the new image projected in the right place. So if you moved your eyes quickly, the machine couldn't keep up. Fortunately, this "Saccade" feature of the brain that "turns off" the video signal from your eyes when they are moving quickly, worked in our favor. Even though we were over a tenth of a second too late in getting the new image drawn, nobody could ever tell. In fact, you'd swear that the image you were seeing was continuously there as your eyes moved - when it was 100% certain that the computer hadn't drawn anything during all of that time.

It's one thing to talk about this stuff in the abstract - but when you see it with your own eyes (or at least don't see it!), it's downright creepy! You'd look to your left - then quickly glance over to your right and you'd be utterly convinced that you'd seen a continuous sweep of images in-between - and even be able to provide a reasonable description of what was that you'd seen there. But you could check the logs on the computer and know for sure that it never drew anything other than the image at the far left and then at the far right. Everything else was 'faked' by your brain in order to give you the illusion of continuous vision.

The brain is a deeply weird machine! SteveBaker (talk) 23:24, 14 March 2010 (UTC)

You may be interested in perception of time and time perception. ~AH1^(TCU) 01:59, 15 March 2010 (UTC)

Temperature of a high-gravity planet?

Say that there is a planet with a very strong gravitational pull. Would the gravity condense some liquids into solid form, meaning there is more ice on the surface? Or would it cause more heat due to friction? If the strength of the planet's gravitational pull was the only differing factor, would the resulting surface conditions be more likely to be hotter, colder, or about the same as an Earth-like planet? 97.104.210.67 (talk) 05:57, 14 March 2010 (UTC)

Gravity won't condense anything, pressure does that. Gravity is a factor in determining pressure, but it isn't the only one. Venus' surface pressure is about 90 times that of Earth despite having approximately the same surface gravity. --Tango (talk) 06:06, 14 March 2010 (UTC)

Excuse me for my mistake, I should have remembered that, but it is 1 AM my time. I'm just curious to know which result is more likely to occur. 97.104.210.67 (talk) 06:09, 14 March 2010 (UTC)

(1) regarding the "friction": Compression heating is only important for "young" planets. When a proto-planet forms and compresses (becomes more compact), the gravitational force performs thermodynamic work, and therefore heats up and melts the proto-planet material. Surface of young planets are therefore very hot, much hotter than their eventual surface temperature. Cooling rate depends on surface to volume ratio, presence of primordial atmosphere, and so on. But some time (10⁶ - 10⁹ years, AFAIR) after the accretion and the compression stops the surface does cool down, and eventually approaches its steady-state temperature. The core remains hot, though. Steady-state surface temperature of planets depends most of all on the balance between the heat influx from the star and the radiative heat loss into space. Slow release of trapped heat from the core and additional heating of the core by radioactive decay contribute less to the surface temperature. Tidal heating by other gravitating bodies is much weaker yet. So in the very young planets "friction" if more important while in the older ones the "friction" (compressional heating) is no longer very important as far as the surface temperature is concerned. (2) regarding the gravity & atmospheric pressure effect. On a planet without an atmosphere, surface pressure is zero regardless of the gravity strength. To have a nonzero pressure you need a nonzero quantity of material to exert that pressure from above. For example, Earth has 10 tons of atmosphere over every square meter of its surface at sea level, thus the atmospheric pressure equals the force exerted by the weight of 10 tons per square meter. As you climb the Everest, gravity pull changes negligibly but atmospheric pressure drops a great deal. It is therefore incorrect to say that gravity will condense something on the surface. You need a atmosphere to do that. However, even though 1 bar of pressure feels like a lot, it is not nearly enough to change the melting point of most solids by any significant amount. Typical slopes of melting curves of metals are in the ballpark of 1 degree Kelvin per kilobar IIRC. For water ice, it is approximately minus 10 degrees Kelvin per kilobar; that is, if atmospheric pressure on Earth was 100 times stronger, water freezing point would have been 272 K and not 273 K. --Dr Dima (talk) 08:32, 14 March 2010 (UTC)

Our article Triple point provides a pretty good overview of the story on the relationship between pressure, temperature, and phase. Looie496 (talk) 17:17, 14 March 2010 (UTC)

So I guess the answer is that there wouldn't be much difference? Okay! Thanks for answering my question. :) 97.104.210.67 (talk) 18:18, 14 March 2010 (UTC)

Is Chrysler 300 equiped with brake override system?

model: 2.7L V6

year of produce: 2006 Zhoudp (talk) 06:14, 14 March 2010 (UTC)

I should clarify that you mean an antilock brake override, so as to avoid any advice on draining out all the brake fluid... :-) StuRat (talk) 13:50, 14 March 2010 (UTC)

This may vary by model year. However, in my searching I find no references to any such switch, so I would tend to say "no". Perhaps someone with that car model can verify this (or you could always call a dealership). StuRat (talk) 14:01, 14 March 2010 (UTC)

Marine Creatures

what is the best topic for my report regarding Marine Creatures? —Preceding unsigned comment added by Gerlie gedoria (talk • contribs) 08:05, 14 March 2010 (UTC)

Cephalopod intelligence is very interesting, in my opinion, and a sufficiently obscure topic to make it a good report. --Tango (talk) 08:12, 14 March 2010 (UTC)

Diatoms are created too and they have interesting shapes! Graeme Bartlett (talk) 08:32, 14 March 2010 (UTC)

I added to the weird title to make it useful. StuRat (talk) 13:47, 14 March 2010 (UTC)

I completed tidying the title. Cuddlyable3 (talk) 11:51, 15 March 2010 (UTC)

I always retain the original title, in case it's used as a search term to find the Q. StuRat (talk) 13:03, 16 March 2010 (UTC)

It's much easier to write a good report if you focus on a question rather than a topic, and you will probably write a better report if you focus on a question that interests you rather than a question that somebody else suggests to you. Looie496 (talk) 18:21, 14 March 2010 (UTC)

What about the intelligence of cetaceans, shark finning, ocean acidification, hydrothermal vents, the invasion of jellyfish, or turritopsis nutricula? ~AH1^(TCU) 01:57, 15 March 2010 (UTC)

[[:File:Vampyroteuthis2.jpg|thumb|Glow-in-the-dark vampire squid! Nimur (talk) 17:37, 15 March 2010 (UTC)]]

Bioluminescence is a fascinating topic; it is found in many different types of marine invertebrates and glow-in-the-dark fish. Whether you're in third grade (and just want some nice photographs and a few sound-bite science facts); a high-schooler in need of in-depth ecological analysis of the hadal zone and a food-chain based on minimal/zero solar energy; or if you're a Ph.D.-level biologist who wants to discuss photophoric production of bioluminescent protein compounds, this topic will make an excellent topic for your marine creatures report. Nimur (talk) 17:37, 15 March 2010 (UTC)

Methane

The hydrogen atoms of methane are distributed evenly over a sphere. How can you show that this angle is 108 degrees? (I don't know if I should ask this on the math ref desk). 173.179.59.66 (talk) 09:23, 14 March 2010 (UTC)

Actually, it is 109 degrees. More precisely, it is arccos(-1/3). The hydrogen atoms are at the vertices of a tetrahedron, so that is the shape you need to study. This derivation is pretty good. --Tango (talk) 09:45, 14 March 2010 (UTC)

This is the N=4 case of the Thomson problem, for which no general solution is known.83.134.168.71 (talk) 14:03, 14 March 2010 (UTC)

Cool, thanks. 173.179.59.66 (talk) 01:35, 15 March 2010 (UTC)

How can i analyse......subject

my name is sumanthdarisi...i am engineering first year student of ECE. I hav aolt of passtion in creating something new eletrical or electronic goods, but i dont know the internal working procedure of the related things of my ideas . for example : I hav an idea to get mobile numbers of others without asking them... jus by passing few invisible rays on to their mobiles...which will received by their mobile and then send back to me.....so i need to know how should i proceed my experiment......plz help me to move forward!! —Preceding unsigned comment added by Sumanthdarisi (talk • contribs) 10:40, 14 March 2010 (UTC)

I'm afraid that already exists, in various forms (eg. the iPhone "Bump" app). That's the hardest bit of inventing things - finding something which hasn't already been invented! --Tango (talk) 10:47, 14 March 2010 (UTC)

Asperger's Adam had it so good... :) 82.113.121.96 (talk) 12:13, 14 March 2010 (UTC)

Instead of using the cell phone itself for this, how about a separate rechargeable battery powered device ? Each could send and accept info like you'd find on a business card. They would need to have a very short range (only a few feet), and probably should only record contact info if you stay near the source for a minute, to eliminate contact info from everyone you walk by. At the end of the day you'd have a list of contacts, listed by time of day they were received. Many would be contacts you don't want, of people you just happened to stand by, so you'd need to go through and eliminate those. For those you keep, there could be a USB port to upload that info to your computer, cell phone, etc. However, note that there would be a privacy issue, in that not everyone would be willing to share their contact info with everyone else. StuRat (talk) 13:42, 14 March 2010 (UTC)

The electronics business isn't actually very short on ideas - the difficulty is in moving them from ideas into actual implementations - and then marketing those things to the public. To turn your idea from a thought to a thing requires quite a lot of deep knowledge. You'd need a clear understanding of stuff like bluetooth protocols or RFID scanners. It's possible that you could implement something like this on an existing cellphone (either iPhone or Android) - but that would require some fairly sophisticated programming skills.

I used to work for Philips research labs in the UK and we were told never to accept or acknowledge ideas like this from the general public - and in my present job as a computer games programmer - I have to live under the same rules. The reason for that is that these companies are not short of ideas for new products - so there is little benefit in taking an idea from outside of the company - and the risk of doing so might be that someone in the company might already be working on a similar idea and we wouldn't want to be sued for 'stealing someones idea'. Sadly, this means that unless you can do the work of going from idea all the way to a demonstrable product by yourself, the best way to get your ideas into products is to go and work for a company that does that kind of thing. There are companies who employ people only to have good ideas - but getting one of those jobs right out of college is almost impossible...you have to start in either the artistic, engineering or marketing fields and become known for having bright ideas.

In either case, you're going to have to study hard in the field you're interested in - do electronics - learn programming skills - get at least a basic understanding of math and physics. As you start to become proficient in those areas, start making things with off-the-shelf parts...I'd recommend using something like the Arduino system which consists of small, cheap computer boards (they cost about $26 online) and a relatively easy to use programming system. There are tons of online resources for how to add electronics to the Arduino - and using one of these, you could probably make some working prototypes of a short range identification exchanger...or whatever other idea you might have.

As for the idea itself, it does indeed already exist in the iPhone "bump", it's also done to some degree in the Nintendo DS where complete strangers who are in radio range can even share games and such like. The Microsoft Zune MP3 player allows music to be shared in a similar way. So this idea is already "out there" and I doubt you'd get credit for originality there.

SteveBaker (talk) 15:11, 14 March 2010 (UTC)

Just out of curiosity, WHY do you want to do this? (More specifically, why would I want you to get my phone number without my knowledge?)24.150.18.30 (talk) 16:48, 14 March 2010 (UTC)

The type of question, where the questioner has an idea for an electrical/electronic device but knows nothing of electricity/electronics, is in the tradition of such famous inventors as Samuel Morse, an idea man who relied on the work of Joseph Henry and Alfred Vail to make a telegraph that worked more than a few yards. Similarly Alexander Graham Bell knew very little of electricity and relied on Thomas A. Watson and others to make a working telephone. Being convinced a device can be made to work and finding funding for development are the important contributions an "idea man" can bring to the art of inventing and developing a device, especially if "conventional wisdom" says it won't work or is impractical based on earlier unsuccessful experiments going at it in some different way. Often the need for a device has not been seen before the inventor presents it (like the telegraph, the telephone, or the Xerox). Historically, people have also said "It has already been invented," pointing at some device which is not at all the thing proposed. In recent years, some billionaire heads of software companies, often described as software experts, have been far from their companies' best programmers, and would be lost trying to maintain or improve the present software. Edison (talk) 18:03, 14 March 2010 (UTC)

There is a world of difference though. Attaining a knowledge of simple electricity from other people in the field is childs play compared to something like (for example) understanding the software and hardware of a cellphone in order to change how it's bluetooth interface operates. You can easily summarize all you need to know to build a practical telegraph or telephone on one sheet of paper. It takes years of study to learn to program and to understand the way modern data transmission protocols work. A lot of what those early inventors did was trial and error - but that's absolutely not going to work with the kinds of sophisticated electronic and software systems that our OP is considering. It's not for no reason that largely self-educated individuals so rarely make ground-breaking technological advances anymore - and even well-educated people need the backing of teams of engineers to bring their ideas to fruition. SteveBaker (talk) 13:24, 15 March 2010 (UTC)

I'm not really sure if I understand the OP's suggestion but apps for phones using Bluetooth to automatically exchange details have I'm pretty sure existed for a very long time, probably not long after Bluetooth was first available on phones or PDAs. E.g. [1] and exchanging business cards is part of the OBject EXchange protocol. (These weren't necessarily automatic, but I strongly suspect fairly automatic options existed although likely to be turned off by default for obvious reasons, and BTW by automatic I mean does it without you asking, clearly you don't have to enter details which are already stored in the device, in other words the actual exchange would always be fairly automatic, it's just whether you automatically send the details, and automatically accept the details that I presume we're talking about here.) These do of course have compatibility issues (although OBEX is a defacto standard) and more importantly, people don't generally want to exchange details with random people (even if you don't mind receiving, few people want to give out their details to any random person), so they're of most interest at conferences and the like.

Of course Bluedating has also existing for a long time, [2] [3], these I believe work in various ways but would usually include some sort of profile (at a minimum something like man seeking woman etc). Once they meet a match within range, they may exchange additional details of that person, they may start a Bluetooth chatting app so the people can talk etc, I even heard of one that wouldn't tell you anything other then a compatible person was in range (can't remember if it was Bluetooth or even a phone or a seperate device, may have been in Japan), well obviously it must still internally exchange some details so they know your compatible which you can hack, but the idea is you're supposed to find the person yourself, I believe it would beep louder as you got closer. While these have tended to concentrate on dating, since that's the most likely case when people are going to want to exchange details with random people, I presume many allow those simply looking for friends.

Of course more generally there are apps which allow you to chat with people in range (and repeating what has already been said, exchange details with people in range). Indeed concern over privacy given all these possibilities was one of the early worries about Bluetooth (along with security) and there are the more dubious devices which allow you to monitor all devices in range and look out for anything including access things and do things you may not have been intended.

Of course while not working on a phone to phone communication level, missed calling someone has been a fairly standard way of giving someone your mobile number in many parts of Asia (also used for other things of course, as our article partially mentions) since long before Bluetooth, although still requires one party to get the number some how (not that it's that uncommon one party may have it but the other party won't, e.g. if someone sends it in an SMS) although neither of these (SMS or missed calls) are generally completely automatic. Well you could easily make a phone which saved all missed call numbers that aren't already present to the address book but still won't have details on who the person is. Evidentally you can send/receive vCards via SMS on some phones [4] [5] so it can be fairly automatic with SMS (although probably most either just type the number or add it with the phone but not as a vCard and most phones generally recognises numbers in SMSes).

Nil Einne (talk) 21:05, 14 March 2010 (UTC)

barbs

i was prescribed a barbiturate and Tylenol mix for migraines is that common? its Butalbital. will only Butalbital work or do all barbiturates work? —Preceding unsigned comment added by Thekiller35789 (talk • contribs) 11:08, 14 March 2010 (UTC)

I'm afraid we can't give medical advice. If you want to check that your doctor has prescribed the right drugs you need to get a 2nd opinion from another doctor, not random people on the internet. --Tango (talk) 11:09, 14 March 2010 (UTC)

I'm not convinced this is medical advice. The OP isn't asking about the actual prescription of drugs but rather whether the one he/she was given is a common mixture, and whether or not that's the only barbiturate which is prescribed for migranes. Seems like a request for common information related to his experience rather than direct medical advice. What harm could come from answering the aforementioned questions? Regards, --—Cyclonenim | Chat  15:28, 14 March 2010 (UTC)

If I knew the answer, I'd give it; this is basically saying "my doctor said that I should do this, so I'm going to do it, but I'm curious how many other people are supposed to do it". Nyttend (talk) 15:45, 14 March 2010 (UTC)

In my opinion, any time a question refers to a medical situation and an answer has a potential to lead to a change in behavior, it should be considered a request for medical advice. Looie496 (talk) 17:11, 14 March 2010 (UTC)

I don't think you've thought this through. This would mean that we couldn't tell people that cigarettes cause cancer, for fear that they would change their behavior (stop smoking) as a result. What's wrong with Kainaw's criterion? Comet Tuttle (talk) 17:37, 14 March 2010 (UTC)

This book [6] and that [7] say you can buy it as a comination of substances in one medicament. And that one [8] says it is common in the US for migranes.--Stone (talk) 17:16, 14 March 2010 (UTC)

I think both Tango and Cyclonenim are right on this but I think also, that questioner would benefit from a bit of background, so as to be clearer of what they should be asking their own doctor for by way of clarification. For it is their own prescribing doctor that should answer queries about the medication and treatment. So I've added this below, which I think avoids advice.
Q. “Is it common” . Answer: A doctor may say to his patient that he is prescribing it 'off label.' This means that there is no good medical trial evidence (yet?) that it works for migraine. Therefore, the doctor has to take responsibility for using his own judgement of the risk verses the benefits to his patient. Doctors hate proscribing 'off label', so yes, from that fact alone, one can conclude that this mix is not commonly prescribed for migraines.
Q.”do all barbiturates work” Answer: The addition of a barbiturate (of any type) does not increase the analgesic effect in anyway. So 'work' is the wrong word. It is just there as a sedative to give some relief from the anxiety and distress resulting from suffering 'this type' of intense pain.
If the questioner also registers their email address with Medscape and then search for “Fioricet Oral.” The whole of the patient information leaflet stuff (which should have been included with the medication) and more besides, is there. Including what to talk to the doctor about.--Aspro (talk) 17:18, 14 March 2010 (UTC)

iv read the barbs also have analgesic effect thou. otherwise they wouldent use them for migrans cause u can die eeasy —Preceding unsigned comment added by Thekiller35789 (talk • contribs) 19:23, 14 March 2010 (UTC)

I would add that I've never known barbiturates to be used in the treatment of migraines. More common treatments are β-blockers and Calcium antagonists. Regards, --—Cyclonenim | Chat  20:38, 14 March 2010 (UTC)

Beta blockers are usually given as prophylactics, however I believe 5-HT_1D receptor agonists are the most common treatment (triptans). --Mark PEA (talk) 23:11, 14 March 2010 (UTC)

As it happens, I've just been reading an essay by Avram Davidson in which he mentions that he was prescribed, for migraines, pills containing phenobarbital, caffeine, and ergot. This was probably at at least 50 years ago, but it shows, at least, that barbiturates have been used in the treatment of migraine. Deor (talk) 01:35, 15 March 2010 (UTC)

Whilst true, I suspect that ergot would have been the primary ingredient in that concoction as it's a vasoconstrictor and therefore useful for treating headaches, as long as you have the correct dosage. I imagine the phenobarbital was there to calm the patient rather than treat the actual complaint. Regards, --—Cyclonenim | Chat  12:32, 15 March 2010 (UTC)

the barbs are not used to calm they would use another safer sedative. they must have pain killing properties.

Moments in space

Hi ppl. I am obsessed with the following...

1)Does centre of mass exist in outer space? 2)In space, is there moment of a force? If so, what is the pivot in a rigid uniform bar? And Lastly, 3) What exactly is the pivot anyway when it comes to taking moments. I mean, I am kindy confused about the pivot thingy as to how every point manages to turn around it while others remain in place.

I will be glad to knw the answers. Thanks

Blueberry —Preceding unsigned comment added by 122.99.98.17 (talk) 16:54, 14 March 2010 (UTC)

For your first question, see barycenter, binary system and Lagrange point. ~AH1^(TCU) 01:43, 15 March 2010 (UTC)

Let me explain why the center of mass still exists in space, and, in fact, is the same center of mass as on Earth. (I will assume that the object has a uniform density in a uniform gravitational field for this discussion.) The part that's confusing you is probably that you can balance an object on it's center of mass here on Earth, but not in space. But there is another way to measure the center of mass in space. If you push an object anywhere other than at that point, it will go into a spin. If you push it right at the center of mass, it should move, but not rotate. StuRat (talk) 02:41, 15 March 2010 (UTC)

It might help if you remember that the motion of a rigid body (on Earth or in outer space) under any system of forces can be considered as made up of the linear motion of its centre of mass (just treat the body as a point mass with all forces acting there) plus the rotational motion produced by the moments of the forces about the centre of mass. (I used to be able to prove this, but can't remember now. I'm sure that someone will provide a link to the appropriate article.) You might be confusing centre of mass with centre of gravity (the point through which the weight acts). They are the same in a uniform gravitational field. Dbfirs 10:13, 16 March 2010 (UTC)

Yes, and I added a comment to say that, now, although how often does one find oneself in a non-uniform gravitational field ? StuRat (talk) 13:02, 16 March 2010 (UTC)

A simple Buffer Question

Hi WikiRef-ers.

Hypothetical question for you...

Lets say you had a buffer solution of carbonic acid (H₂CO₃).

In this solution, the ratio of HCO3- to H2CO3 is 20:1. The [HCO₃^-] is 25 meq/L. [H₂CO₃] is about 1.2. The pH is 7.4.

Now, lets say you left the room to get some lunch, and a mischeivious co-worker sneaks in and adds a certain amount of H2CO3 to your buffer. You now know that the concentration in your solution of H2CO3 is about 1.5.

With that information, can you calculate what the pH AND the HCO3- is in the new solution?

Thanks!

--Cacofonie (talk) 18:52, 14 March 2010 (UTC)

Like most homework questions this easy. Lets look if there is the Henderson–Hasselbalch equation and after you put in all the data you get !ops! I was not allowed to answer homework questions. --Stone (talk) 19:34, 14 March 2010 (UTC)

That won't quite cut it in this case, because you don't know what the new concentration of HCO3- is (adding the carbonic acid shifts the equilibrium). You need to do an ICE table, where 1.5 is the final concentration of H2CO3, and you don't know the initial concentration. Buddy431 (talk) 19:46, 14 March 2010 (UTC)

Never mind: in this case, the equilibrium shifts so little that you can approximate it with the HH equation. Incidentally, the concentration of HCO3- is still 25, the change being several orders of magnitude smaller. Buddy431 (talk) 20:01, 14 March 2010 (UTC)

Actually, its not a homework question! I`m just trying to figure out arterial blood gases. It`s said that in Acute Respiratory Acidosis (i.e. an increase in H2CO3), for every 10 mmHg increase in the PCO2, your Bicarb increases by 1 meq. But, I`m not sure how that fits into this HH business if the quantity of bicarb produced is so minimal.

blagh --23:37, 14 March 2010 (UTC) —Preceding unsigned comment added by Cacofonie (talk • contribs)

no longer on speaking terms

Does Wikipedia have an article on the phenomena of people who are not on speaking terms? Such people are said to "not talk to one another." It is a human expression (or in-expression). It occurs between relatives, in families. It occurs between people who were once friends. It takes place between people who live in the same neighborhood, and ostensibly have to walk past one another. Is anything known about this human phenomenon? Has it been studied scientifically, methodically? Do we have an article or a subsection, on people who, due to some event or an interaction that has transpired — are no longer on "speaking terms?" Thank you in advance for any answers. If this needs to be moved to another page — fine. But I am asking mostly about the peculiar psychological condition. By the way, one interesting thing I have heard is that sometimes a point in time is reached at which the involved people no longer even remember what precipitated the situation! Bus stop (talk) 19:16, 14 March 2010 (UTC)

It seems that it's a part of social alienation and social rejection, especially the latter. There may be links more from those articles. -- Flyguy649 ^talk 19:42, 14 March 2010 (UTC)

It seems more like mutual deprivation: each one has made a calculation that there is a net gain in depriving the other of the mutual relationship of simply speaking. But that is just my own hypothesizing. Bus stop (talk) 19:55, 14 March 2010 (UTC)

Both parties appear to be using a tit for tat strategy of not giving each other value in the form of social interaction (mutual defection in Prisoner's dilemma), and are now in a "death spiral" until one of them yields. --Mark PEA (talk) 20:12, 14 March 2010 (UTC)

I don't think this is an example of social alienation, because this rarely occurs in families and usually happens to people who are not befriended by the "alienators". Relavent articles and topics may include mamihlapinatapei, zero-sum game, and wikt:estrangement. ~AH1^(TCU) 01:37, 15 March 2010 (UTC)

Our article about the strange British expression "Sending someone to Coventry" makes interesting reading too. SteveBaker (talk) 12:56, 15 March 2010 (UTC)

Drainage Systems in New York State

I have a question. What caused the development of different drainage systems in New York State? I think the answer is water erosion, but I am not sure. Could somebody help me with this? Thanks.--Lamb99 (talk) 22:05, 14 March 2010 (UTC)

DO you mean waste water drainage systems or watersheds? --Jayron32 00:57, 15 March 2010 (UTC)

Assuming that Lamb99 is referring to watersheds, I'd say that mountain formation (see also the article Orogeny) was the most important factor, with glacial erosion being another major factor. Deor (talk) 01:26, 15 March 2010 (UTC)

I mean any kind of drainage systems. This would be both waste water drainage systems and watersheds. Please give answers for both, and more if possible.--Lamb99 (talk) 21:57, 15 March 2010 (UTC)

The Finger Lakes and the Great Lakes and their associated drainages were created by Ice Age glaciers and ice sheets, for the most part. Niagara Falls too. Pfly (talk) 09:35, 16 March 2010 (UTC)

Doesn't human settlement caused the development of the wastewater system? --Kvasir (talk) 07:49, 17 March 2010 (UTC)

Fission Reactors

I've been reading the articles on fission reactors. I have a good grasp of how and why nuclear fission happens. I can understand how the neutron poisons and neutron moderators slow down and speed up the fission process. What I don't understand is where the process starts. Do they have some fissile material at critical mass and then they slow down the chain reaction? Do they have some fissile material and bombard it with neutrons to get the reaction going? I don't understand where the original fission reaction starts. Anything you can say to help? •• Fly by Night (talk) 22:07, 14 March 2010 (UTC)

The atoms of the uranium or plutonium (or whatever) are spontaneously fissioning all the time at some low level - that's what radioactive materials do. Their atoms are fundamentally unstable. But the neutrons produced mostly fly out of the material as radiation. Only very rarely do those neutrons hit other atoms and causing them to fission in turn. If you increase the amount and compactness of the material, you increase that probability and eventually, at "critical mass", you get a self-sustaining reaction where there is enough material that the neutrons produced by one atom spontaneously fissioning are enough to cause (on average) more than one atom to fission as a result producing more neutrons and yet more fissioning events. At that point, you have a cascading, exponentially increasing chain reaction - an atom bomb. The trick in a nuclear reactor is to control the way those neutrons are absorbed or reflected back into the material to have enough neutrons captured to keep the reaction going at a useful level - but not so many that you get a runaway chain reaction. SteveBaker (talk) 22:31, 14 March 2010 (UTC)

Thanks, but I already know and understand all of that; just as my original question states: "I have a good grasp of how and why nuclear fission happens. I can understand how the neutron poisons and neutron moderators slow down and speed up the fission process." Let me repeat my question. Do they have some fissile material at critical mass and then they slow down the chain reaction? Do they have some fissile material and bombard it with neutrons to get the reaction going? I don't understand where the original fission reaction starts. Anything you can say to help? •• Fly by Night (talk) 22:38, 14 March 2010 (UTC)

As steve explained, the fission is happening spontaneously at a low level all the time. That's where it starts from. It starts from that low level spontaneous fission and grows from there. Dauto (talk) 23:26, 14 March 2010 (UTC)

Check out Spontaneous fission 82.132.139.87 (talk) 00:07, 15 March 2010 (UTC)

I think he might be inquiring about how the moderator and control rods are used to bring the pile to criticality. --Aspro (talk) 00:16, 15 March 2010 (UTC)

Grrr! Dauto and 82.132.139.87: I already know and understand that. But not just any old pile of radioactive material is used in a nuclear reactor. My question seems to be answered below: you start with some fissile material at (or very close to) critical mass, and the control rods keep the reaction manageable and useful. Thanks for your help, I do appreciate it. I think that you're aiming your well intended answers at the wrong level. But thanks again! •• Fly by Night (talk) 19:50, 15 March 2010 (UTC)

Let me take a stab at this, in my fumbling way:

So let's imagine we're hanging out with Fermi and the CP-1 crew underneath Stagg Field. We have a neutron detector next to our pile, which is already a critical mass, with our control rods fully inserted. We're getting some considerable blips from our uranium, just from the spontaneous fissions and maybe from a few secondary fissions from those, but it's basically the same as if we just had some uranium metal lying around (nothing particular to fissioning). We start to remove the control rods. Without something absorbing those neutrons from the spontaneous fissions, they are going to start creating all sorts of secondary and tertiary fissions and so on. Assuming we've done this in a safe way, with our control rods only partially out, there's going to be a cap on how many generations are likely to fission, so we aren't self-sustaining yet. But we're getting a lot more neutrons, a lot more fissions. We pull out the control rods more, the fissions start really taking off, and at some point we have them out enough that the reaction can be self-sustaining. Now this graph in this instance looks like this (note that at one point they change the scale to keep it from going off the paper).

Now, we don't have to create the critical mass first, with control rods already inserted, and then remove the control rods. That's just an easy and safe way to do it. You could create the critical mass incrementally and it would have the same effect. As you start getting enough material in there for the reactions to continue exponentially, they will start doubling quickly.

It's important to remember that the important part about reactors (and bombs) is that you have enough reacting material for an exponential chain reaction (each fission producing 2 or more other fissions). If you have something that is not producing much of a chain reaction, it will not be terribly impressive—a measurable but piddly collection of atoms fissioning. If you allow the reaction to start growing exponentially, it really becomes something impressive, and fast—the Wheat and chessboard problem, but with neutrons. --Mr.98 (talk) 00:35, 15 March 2010 (UTC)

Note that with a reactor, I think in most (all?) cases you can just let the reaction build up "slowly" from spontaneous fissions. With a bomb, you don't want to wait that long (you want an efficient chain reaction going off within 600 nanoseconds or so), so you use a neutron generator to just kick-start the reactions in a major way. --Mr.98 (talk) 00:43, 15 March 2010 (UTC)

So the answer to my question is that the fissile material is already at critical mass, but the control rods (acting as a neutrol poision) are stopping the fissile material from undergoing an uncontrollable chain reaction? About your question Mr. 98: I think that any pile of Uranium or fissile material will undergo nuclear decay; some of which will result in fission, and some won't. But within some finite time it will almost all decay away until it's something stable. •• Fly by Night (talk) 19:50, 15 March 2010 (UTC)

I don't think that's right. Such a reactor would be extremely dangerous, as a thermonuclear explosion would result if the control rods were withdrawn. I'd say it's best to think of a continuum between the radioactive decay that happens in naturally occuring uranium in rocks and that in nuclear reactors. That is, the rocks produce some nuclear energy, but at such a low level it's difficult to use. By refining and enriching the uranium, we can crank up the reaction rate until we get something usable for power generation but still far short of an uncontrollable chain reaction. The control rods are then used to change the rate, depending on demand, and also to shut down the reactor for maintenance, etc. StuRat (talk) 20:04, 15 March 2010 (UTC)

I'm sorry, but you are very wrong on many important points. No thermonuclear explosion (no nuclear explosion, much less a thermonuclear one). Yes, you can have the reactor at a critical mass with the control rods in (this is exactly what CP-1 was). Critical mass just means the reaction is self-sustaining. Yes, if you draw all of your control rods out of a reactor quickly, it can be dangerous. No, it will not explode like a nuclear bomb. Yes, enriching to different degrees can affect the reaction rate, but no, that is not really relevant to this question. (You can do it with unenriched, "natural" uranium if you have the right moderator. And in fact, this has been done with actual rocks!) Keep in mind that the main difference between a reactor and a bomb is that the reaction in a bomb is FAST—all of uranium fissioning in less than a second. In a reactor the reaction is dragged out, not nearly so rapid, and the energy release is done at a more manageable speed (so instead of blowing up the plant, it just heats some water). Making a reaction go off fast enough to be like a bomb is hard—that's why bombs have to have extremely enriched material, clever internal engineering, etc. --Mr.98 (talk) 21:57, 15 March 2010 (UTC)

Thermonuclear? How would fusion occur in a fission reactor? I did write above "at (or close to) critical mass". I forgot to write "or close to" in my last post. Okay, so if it's not at critical mass, then what would the neutron multiplication factor be? It must be pretty close to 1. That's why there are so many SCRAM safe guards. If you pulled all the control rods out and left them out then you'd be in some serious trouble! •• Fly by Night (talk) 20:47, 15 March 2010 (UTC)

Nuclear decay is fission. Skooled. --Sean 20:51, 15 March 2010 (UTC)

Not quite. Fission is one mode of nuclear decay, but not all modes of nuclear decay are fission. See here. •• Fly by Night (talk) 21:47, 15 March 2010 (UTC)

StuRat is wrong. It can be at a critical mass. You can also do it by slowly assembling a critical mass cumulatively. Either way would work. By definition, in a non-critical reactor the multiplication factor is less than 2. In a critical reactor it is 2 or greater. And no, it won't blow something up just because it is critical! If the reaction is slow (as it is in reactors), you'll get a lot of neutrons, and a lot of heat. And in some designs, yes, if you let it keep getting hotter and hotter, you'll have a meltdown. So real-world reactor operation is about keeping enough heat for things to work well but monitoring things so that they don't get out of hand. (Meltdown isn't inevitable, depending on the design. A TRIGA for example is set up so that the increase in heat corresponds to a decrease in neutron efficiency, so it levels off naturally.) --Mr.98 (talk) 21:57, 15 March 2010 (UTC)

Some confusion appears to have crept in here. Is this clearer. Firstly it is not a 'critical fuel mass' one wants but a 'fuel loaded reactor pile' to go critical. The former condition can lower the value of the local real estate and much of the real estate most States downwind of the reactor. This is because the energy generation is so fast in a 'critical mass' that it is far beyond our technology to control it. However, the next bit of the answer depends on what type of reactor one is talking about, and so the question as asked is a bit difficult to answer. But I think it would be a fair generalisation to say that one employ the moderator(s) (and the addition of more fuel rods) to bring the reactor up to criticality over the long term time frame and use the control rods for short term fine control. In some reactors you can modify the liquid moderator to soak up some of the neutrons (with say boron) in a freshly refuel pile and then slowly adjust the mix as the fuel gets burnt. All the time using the control rods to control to adjust for short term fluctuations in output of the pile and electrical power demand placed upon the station. So no, you don't start off which a critical mass even though the pile may contain tons of fuel. That reminds me. The problem with the the Chernobyl reactor design was that this slow spongy characteristic was reversed a low power levels and so became very unstable at the hands of an ignoramus. The British Gas Cooled Reactors were extremely stable in comparison, (if a little inefficient). --Aspro (talk) 21:49, 15 March 2010 (UTC)

Just because something is a critical mass does not mean that we cannot control it. It is unfortunate that almost all of our physics in the critical mass and nuclear chain reaction articles are about bombs, but there are critical masses in reactors as well. The difference is that we control the speed of the reaction. Critical mass just means "the smallest amount of fissile material needed for a sustained nuclear chain reaction." It does not mean "out of control chain reaction". Assembling a critical mass very quickly is dangerous—bomb-like—but assembling one slowly is a source of neutrons, heat, etc., all the stuff we want from reactors. As nuclear reactor puts it: "Nuclear fission reactors produce heat through a controlled nuclear chain reaction in a critical mass of fissile material. All current nuclear power plants are critical fission reactors, which are the focus of this article. The output of fission reactors is controllable." --Mr.98 (talk) 21:57, 15 March 2010 (UTC)

(e/c) Okay, fair enough. So to ask once again: "if it's not at critical mass, then what would the neutron multiplication factor be?" (or at least a good estimate) •• Fly by Night (talk) 22:03, 15 March 2010 (UTC)

It been year since I did any any of this and I was only interested in the hard mechanical bits and control systems, so I would rather some one else carried this on. However, k = 1 is what one wants to achieve at every power level. So the rods are withdrawn or inserted to increase or decrease the flux until the required electrical power is being put into the distribution grid and then the rods are adjusted to bring it back to k = 1. Further adjustments will need to be made over time as the 'poisons' that get generated and decay have a time lag different to the power output.--Aspro (talk) 22:25, 15 March 2010 (UTC)

Imagine the evolution of your chain reaction of your critical mass reactor that has its control rods fully inserted. In the beginning your k is going to be quite low. You withdraw your control rods. k increases, to something >1 (if it were just =1 at the beginning, you would not have any growth beyond your subcritical stage). (I imagine that exactly what you want k to be at this stage varies based on the size of the reactor, the level of enrichment, the heat changes it can tolerate, etc. If k goes too high too fast, you'll have a serious problem in any reactor that is not designed to go prompt critical. Some reactors, again, can do this safely, like a TRIGA, which are designed to pulse.) At some point you don't want it to keep going indefinitely (which increases heat), and so at your optimum level, you re-insert your control rods so that k=1 again. Self-sustaining, but not out of control. Critical—but delayed-critical, not prompt critical. --Mr.98 (talk) 22:37, 15 March 2010 (UTC)

And I suppose it would be useful to reiterate at this point, that at start up ALL the neutrons needed to create the next generation of neutrons are supplied by the normal spontaneous fission within the fuel. Most designs need enriched fuel so that there are more spontaneous fissions to act a seeds. This need is dependant on mainly the efficiency of the moderator but better moderators can run on natural strength uranium. That is not to say a reactor wont produce k = >0 on a natural uranium ratio (even the Cavendish uranium reactor managed that in England before the WWII), it is just that they would be uneconomic to run. Maybe all these articles need a bit of polishing.--Aspro (talk) 23:15, 15 March 2010 (UTC)

So the fissile material without any control inserted is critical? The fully inserted control rods will soak up a lot of the neutrons and so k << 1. This begs another question: how do they build these reactors? Taking the control rods out would be very dangerous, so what happened when they built the reactor and there were no control rods? Do the build up the pile around the control rods out of pieces of subcritical material and then bring it up to critical? •• Fly by Night (talk) 20:31, 16 March 2010 (UTC)

"Critical mass" is something of a misleading term. It's a measure of how much mass you need for k to be at least 1, but it's dependant on the material you're talking about, its shape, and the shapes and types of materials surrounding it. You can make a lump of nuclear fuel go from subcritical to critical simply by moving things that are near it: this is how control rods work, and failure to understand it has resulted in a number of laboratory accidents.

Modern nuclear reactors (ie. not CP-1) are built without any fuel in them. Outside the reactor, fuel is stored and transported in shapes (typically rods) that cannot go critical unless you place a number of them in close proximity. As the fuel rods are put in the reactor, enough of them are gathered together to go critical, but now the control rods are preventing this from happening. Once the reactor is fuelled and the operator is ready to begin, the control rods are withdrawn to the point where the reactor goes critical. --Carnildo (talk) 00:46, 17 March 2010 (UTC)

Yes, in other words—you keep the control rods in as you assemble the reactor (and this is not essentially different than CP-1, I don't think, except for the fact that the CP-1 reactor was basically just fuel, moderator, and control rods, and nothing else). The amount of material would be critical if the control rods were not there, but they are there. When you want it to actually start to go critical, you start to remove the rods. It's not that complicated. If you start putting together material without control rods, it can go critical, and that is certainly dangerous. (This is one of the really dangerous things about the German nuclear reactor that we being built during WWII—they essentially had no control rods, just a lump of cadmium they were going to dump on it if it went critical. The odds are it would have killed the scientists involved if they had actually gotten it working.) Accidental/uncontrolled assembly of critical masses leads to criticality accidents, where you get a burst of neutrons and/or heat, which can be very harmful to people nearby. --Mr.98 (talk) 14:29, 17 March 2010 (UTC)

is it possible to detect, at a distance the power of the mind?

I know you can detect mental activity with electrodes placed directly on the skull. My question is: is it possible to detect mental activity from a distance (ie not with electrodes touching the skull). I don't mean like with an infrared heat scanner, rather I mean actual thinking, so that you can detect, at a distance, whether someone is engaged in a certain intellectual activity versus just spacing out. Thank you. 82.113.121.89 (talk) 22:37, 14 March 2010 (UTC)

pet scan might interest you. Dauto (talk) 22:53, 14 March 2010 (UTC)

Neuroimaging might interest you as well. Dauto (talk) 22:57, 14 March 2010 (UTC)

Of course we can. We are not always right, but we often can understand what is going through another person's mind. There are no instruments that do that. alteripse (talk) 00:43, 15 March 2010 (UTC)

On the Reference desk, we can often detect mental activity, as well as spacing out, in our contributors, by means of keyboards plus the internet. But more concretely: neuroimaging can do the sort of thing you are talking about, if the person's head is inside a big instrument. But if you mean, could we do something like that for somebody not wearing or inside a big measuring instrument, I don't think so. Now, the catch here is that you could imagine some sort of technology in the future that stretched the bounds of "a big instrument" to mean, "within a large area of space" or "inside a specially equipped room of a building" or something like that. But I don't think we have anything that sensitive yet. The signals coming out of people's brains are probably too feeble to be measured accurately (and without interference) without something right next to their head, but I don't know that for a fact. --Mr.98 (talk) 00:52, 15 March 2010 (UTC)

It's theoretically possible, but the voltages on the skin outside the skull are already very small, and the voltage gradients in the surrounding air are orders of magnitude smaller. There must also be electromagnetic radiation, but its magnitude is infinitesimal. So it would take an extremely clean recording environment and ultrasensitive recording equipment to have any chance. I'm not aware of anybody having ever attempted this. Looie496 (talk) 05:25, 15 March 2010 (UTC)

The best research I've seen recently on something somewhat related to this was the use of magnetic resonance imaging in coma patients. For a long time it's been assumed that coma patients have no conscious thought but when these patients are placed in an MRI scanner, and asked certain questions and told to respond in a certain way, we can use the results to indicate yes and no answers. So for example you could ask the patient to think of their favorite film if they wanted to say yes, which would stimulate one part of the brain, and ask them to imagine playing hockey if they wanted to say no, and that would activate a different part of the brain. The patient can then be asked yes/no answer questions and it indicates that at least some comatose patients still have conscious thought.

Okay maybe that wasn't so relevant, but I found it incredible when I first heard it. Regards, --—Cyclonenim | Chat  12:38, 15 March 2010 (UTC)

That supposedly comatose people can be imaged in this way is not the most interesting thing: the most interesting recent result is that using the same experimental procedure you can find the same results in dead fish. (Just Google "dead salmon MRI".) I am currently working on a way to "channel" the intelligence of a dead salmon, however so far I have not been able to reproduce the consciousness effect of the above paper. 82.113.121.99 (talk) 18:34, 15 March 2010 (UTC)

Worse still, it's a matter of focus. There is likely to be almost zero useful information that can be obtained from the sum of the tiny electrical perturbations caused by around 300 trillion synapses firing at the same time (Maybe: "Is this person dead or not?"). Even with electrodes on the scalp, we can only locate signals very approximately and we get only a very broad-brush picture of what major parts of the brain are producing the most activity. Brain scanners are able to get a more precise view of what's going on - but still not down to the level where thoughts could possibly be read. So the answer to this question is "No". SteveBaker (talk) 12:50, 15 March 2010 (UTC)

But a brain scanner (like an MRI) can tell you if significant mental activity is taking place. You can see activity in various lobes, compare it to the "background" rate, and do all sorts of neat things with that. You just have to have the person inside a gigantic MRI machine first. You can't wave a wand at someone on the street and do that. They are, in fact, looking at ways that MRI machines could be used as lie detectors and things like that. I'm not sure we know what the limits of what will be able to be "read" with things like MRI and whatever the next generation of that sort of imaging will be. But I don't see it working "at a distance" (e.g., without your head inside a giant magnet) any time soon, if ever. --Mr.98 (talk) 15:06, 15 March 2010 (UTC)

Yes - it's necessary (as a barest minimum) to have detectors spaced around the head in order to localize the signals you're picking up to a particular 3D coordinate. This imposes limits that would make it utterly impossible to have (for example) a hand-held gizmo that you could point at a person from 30 feet away and say "Hey! This guy is thinking about blowing up a plane - stop him before he gets past airport security!". Hence my comment (above) about "focus" - it's not enough to pick up some overall waveform representing the output of the entire brain - you've got to know whether the neurons were firing in the temporal lobe or some other place - even more detail than that is really needed - and in the limit, you might need to know which of the 300 trillion synapses is firing and when. Without some spatial resolution, there is no conceivable way to extract significant information from a simple one-dimensional waveform. There are also severe issues of range. Because the signal strength of the electromagnetic waves falls off as the square of the distance, you've got to be really close in order to pick up those signals...there are very real physical limits on how far you can be in order to do that. Worse still, brain signals are all over the waveband - these super-faint signals would be completely swamped by cellphone, radio and TV signals washing through everything. SteveBaker (talk) 16:36, 15 March 2010 (UTC)

The above person who said

egg sexer or egg sexing

where are our articles on these? I don't mean chick sexing I mean egg sexing. 82.113.121.89 (talk) 23:24, 14 March 2010 (UTC)

If you mean determining the gender of the unhatched bird, maybe candling ? I don't think you can actually determine the gender that way, but our article is just a stub. I suppose you could do an amniocentesis, but that would be expensive, why not just wait until it hatches ?

If you mean determining the gender of a human baby using a spinning egg, I don't know where the article on old wives tales like that would be. StuRat (talk) 02:30, 15 March 2010 (UTC)

March 15

"Survival of the fittest"

Can we correct a widespread misunderstanding? If I am right (and it should be checked by an expert, which I am not), the Victorian English in which Darwin wrote this phrase has a different meaning from the one most commonly understood in modern English. "Fit" meant appropriate, not necessarily strong and energetic! What was "fittest", then, was what made the best fit, what was most appropriate. I worry that widespread misunderstanding of "survival of the fittest" has wrongly legitimised competitive behaviour, winner-takes-all, and other unhealthy characteristics of modern western society. Can Wikipedia help to shift that misunderstanding, as we move to an ever-more-urgent need for global cooperation on an unprecedented scale?124.176.69.92 (talk) 01:06, 15 March 2010 (UTC)

I believe you are referring to Social Darwinism ("competitive behaviour, winner-takes-all, and other unhealthy characteristics of modern western society"), rather than to biological Darwinism. Intelligentsium 01:13, 15 March 2010 (UTC)

(edit conflict) Yes, I was going to refer you to Social Darwinism as well. You may also want to look at our article on the expression itself, Survival of the fittest, where you will find that Darwin was not the first to use the expression, having picked it up from Herbert Spencer. Deor (talk) 01:18, 15 March 2010 (UTC)

You are right that Darwin (via Spencer) did not mean "fittest" to mean "most strong" or "most vigorous" but rather to mean "most appropriate" or "most adapted." --Mr.98 (talk) 01:19, 15 March 2010 (UTC)

I.e, Darwin's use of "fit" is the sense of Adapted to the requirements of the case; appropriate, suitable. ... LME. Biology. Possessing or conferring the ability to survive and reproduce in a particular environment. LME.. This meaning of the word is older (LME = 1350-1469) than the meaning In a suitable state for strenuous physical activity; gen. in good health. colloq. E18 (E18 = 1700-1729). Source: SOED. Mitch Ames (talk) 01:30, 15 March 2010 (UTC)

Fit certainly doesn't mean the most energetic. Consider the sloth. StuRat (talk) 02:31, 15 March 2010 (UTC)

There are a number of reasons that explain why people assume "fittest" means strongest, but I seriously doubt that it has anything to do with changes in the word's semantic content between Darwin's time and now. FWIW, Dawkins has advocated (though I'm not sure how strongly) changing the phrase to "survival of the fit enough" since resources are not necessarily scarce enough that only a handful of individuals survive; even when it is the case that a just few of the least "fit" do not pass their genes on, the same method of selective pressures effecting diachronic genetic changes are still in effect. — Ƶ§œš¹ _{[aɪm ˈfɹ̠ˤʷɛ̃ɾ̃ˡi]} 06:14, 15 March 2010 (UTC)

It's also worth saying that modern evolutionary thought does not hang on the things that Darwin said. If it were discovered that Darwin's writings have been completely misinterpreted, all that would mean would be that Darwin was wrong - not that modern evolutionary theory is wrong. Hence, if this is true, then it's at best an historical curiosity. This is something that those creationists and intelligent designists would do well to bear in mind as they crawl through Darwin's writings in an effort to discredit him. SteveBaker (talk) 12:36, 15 March 2010 (UTC)

It's true, but I think the poster's original point was about popularization of the theory, in which case appeals to the Great Genius of the Past holds a lot of sway, even if it doesn't in modern scientific circles. (Though even there, scientists do love their heroes.) --Mr.98 (talk) 15:12, 15 March 2010 (UTC)

Certainly "Survival of the organism that fits best into it's surroundings" is a better line than "Survival of the organism that can run fastest and pump the most iron". There are many cases where a less energetic organism can survive with less food or other resources than a stronger one and thereby out-evolve it. Animals who live in dark caves, for example, evolve to lose their eyes - this is clearly "less fit" in terms of "healthyness" (for want of a better word) than an organism with fully functioning eyes - but a much better "fit" into the dark environment of the cave. Darwin wins the prize for being one of the first people to realize that inheritance plus mutation produces speciation. But that doesn't mean that we have to hang onto his every word as "truth" - he was a clever guy - but he didn't know a lot of things that we now understand (how inheritance works for one!). There are many cases in science where we award "naming rights" for a theory to someone who didn't get it 100% right. That's OK. What we're memorializing is the initial insight - not the precise details. Whether Darwin intended a particular meaning of "fitness" rather than another is something that's really only of interest to historians. If it turned out that it was a typo and he had really intended to say "Survival of the tallest" it would make precisely zero difference to modern science. SteveBaker (talk) 16:24, 15 March 2010 (UTC)

I think another thing to keep in mind is that common examples used to illustrate the concept are with animals evolving to run faster, reach higher, and get smarter. The idea that a slow gait, dimunitive size, or a smaller brain might result from environmental changes is commonly called "de-evolution." — Ƶ§œš¹ _{[aɪm ˈfɹ̠ˤʷɛ̃ɾ̃ˡi]} 09:36, 16 March 2010 (UTC)

The idea that there's devolution (biological fallacy)/backward evolution is of course common among creationists and those with an extreme poor understanding of evolution, and it's a common fallacy that evolution always means something is getting more powerful, faster etc but I'm not sure whether even those with such a understanding, baring perhaps creationists are going to think of all such changes as de-evolution, many would recognise that certain traits have evolved to be "less powerful" in organisms that they consider "more advanced" e.g. surely many wouldn't be surprised that some of our ancestors were likely stronger then us (particularly upper body strength). I don't know if they'll say that this is "devolution". The misunderstanding is more at the species level, thinking that humans are "more advanced" then other apes and that if humans evolved to be more "ape-like" that's somehow reverse evolution. Nil Einne (talk) 13:01, 16 March 2010 (UTC)

That science doesn't participate in hero-worship doesn't change the facts that 1) the explanation and notion behind the phrase "survival of the fittest" is still considered correct in modern biology and 2)

::Oops, I guess I shouldn't post too late at night. — Ƶ§œš¹ _{[aɪm ˈfɹ̠ˤʷɛ̃ɾ̃ˡi]} 19:20, 16 March 2010 (UTC)

Hmm - I guess our previous poster "de-evolved" before managing to finish that thought! Anyway - the phrase "survival of the fittest" is only ever used as a shorthand for a full explanation of the theory which properly takes several pages of closely typed text. People working in fields that depend on the theory of evolution are very clear on what the theory really means and I can't imagine any of them claiming that the science rests on that one, somewhat fuzzy, phrase.

The phrase itself isn't even all that useful - it boils down to the tautology: "Survival of those most able to survive" and I don't actually believe that many actual practitioners in the field really DO use it extensively. That shorthand phrase does not in any way diminish what is actually understood in terms of genetics, speciation, etc.

Sadly, the phrase does give the various ID and creationist nut-jobs something to at least try to use as ammunition against what is actually a pretty unassailable theory. Sadly, there are a lot of ignorant and gullible people in the world - and if the ID proponents can "prove that Darwin was wrong" - that would be taken by a majority of the ill-informed to suggest that evolution is wrong - when nothing could be further from the truth.

Evolution is a very strong theory:

1. Basic genetics can easily explain WHY it works, and we have direct evidence proving that it DOES work. (It is unusual for a scientific theory to be able to explain the "WHY" part - we don't know "WHY" relativity or quantum theories work, for example - only that they do work).
2. There direct, long term, evidence for it in the form of fossils.
3. It explains a lot of otherwise inexplicable things (my current favorite being the Recurrent laryngeal nerve - especially in the Giraffe).
4. It makes testable predictions - such as the relatedness of DNA in similar species. We've long known that humans and chimpanzee's share a common ancestor - and lo and behold, when we test that, it turns out that our DNA is 99% identical - more identical than with any other species that we've tested - just as evolutionary theory predicts.
5. It's been observed actually happening in modern nature - for example: antibiotic-resistant bacteria in hospitals, adaptation in the Peppered moth, warfarin-resistant rats, mixamatosis-resistant rabbits.
6. It explains things about ourselves that would otherwise be tough to explain any other way (eg lactose tolerance/intolerance - and why sickle-cell anaemia still persists in the population).
7. It's even been reproduced experimentally - a great example being the E. coli long-term evolution experiment.

By any rational measure, it's a truly great theory. Changing interpretations of the phrase "Survival of the fittest" are so utterly irrelevent to that enormous body of proof as to be laughable. SteveBaker (talk) 13:35, 16 March 2010 (UTC)

So going back to the original question, what would be the best way to correct the widespread notion of the concept of "fittest" being "strongest"? — Ƶ§œš¹ _{[aɪm ˈfɹ̠ˤʷɛ̃ɾ̃ˡi]} 19:20, 16 March 2010 (UTC)

Just explain to people how evolution works. From that point on, it's obvious. SteveBaker (talk) 20:42, 16 March 2010 (UTC)

All right. Let's get on it, folks. — Ƶ§œš¹ _{[aɪm ˈfɹ̠ˤʷɛ̃ɾ̃ˡi]} 21:45, 16 March 2010 (UTC)

Applications of Quantum Electrodynamics

Are there any? 76.67.72.109 (talk) 01:43, 15 March 2010 (UTC)

Quantum Electrodynamics is the best theory we have to explain how electrons interact with electromagnetic radiation and therefore is at the heart of our understanding of all things electric or electronic. The applications are too numerous to count. Dauto (talk) 03:11, 15 March 2010 (UTC)

It may be the most fundamental but do we need so much precision? Couldn't modern electronics work with only the Dirac equation? Most products would work with only Maxwell's equations. 76.67.74.102 (talk) 03:59, 15 March 2010 (UTC)

QED is the quantum version of the theory of electron and photon and as such it includes Dirac's equation. Transistors wouldn't work were not for the quantum nature of the world. Dauto (talk) 04:24, 15 March 2010 (UTC)

The way I interpret the OP's line of thought is as an inquiry into whether the advanced physical description, which is indeed more accurate and correct, is necessary to make applications like electronics work. This is a difficult question to answer. Briefly stated, most engineers who actually build and work with electronics, including semiconductors, never need quantum theory - let alone quantum electrodynamics. However, much of their work is made possible by engineering approximations to the more exact physics - and somebody had to invent those approximations in the first place. That person would probably have benefited from a thorough knowledge of the full physics. Now, it's worth wondering whether a trial-and-error engineering approach, without the theoretical guidance of advanced QED and other conceptual ideas, could have ever led to modern semiconductor technology - but that's idle speculation, because we did have advanced physics to describe things like doping quantum tunneling, band gap energy, and the photoelectric effect. The same can probably be said for MEMS, nano-scale physical chemistry, protein folding, and all the other places where a quantum electrodynamic effect is at play. The applications have been expedited by a great theoretical understanding of the processes; but, for many of these applied areas, the subject and techniques have been sufficiently refined and approximated so that technical work can be done without resorting to a full QED treatment. Nimur (talk) 06:34, 15 March 2010 (UTC)

interstitial defects in ice

Since the hydrogen bonding structure in ice makes such large open spaces, isn't there a lot of opportunity for interstitial particles to get trapped in an ice lattice? Maybe ions like Na+ or Cl-? Why are they expelled from the lattice when water freezes? John Riemann Soong (talk) 03:56, 15 March 2010 (UTC)

Are you sure they are ? Saltwater can be frozen, right ? StuRat (talk) 04:02, 15 March 2010 (UTC)

John Riemann Soong is right. When salty water freezes most of the salt gets left behind. The reason is that salt ions are electric charged and there would have to be charge separation in order to place those ions in the gaps. That's energetically disfavored. Dauto (talk) 04:13, 15 March 2010 (UTC)

Yes but couldn't they be somewhat stabilised by the lattice? I mean the counterion would be in the next gap (or even in the same gap). Or is it more energetically favourable to just kick out the salt? John Riemann Soong (talk) 05:17, 15 March 2010 (UTC)

I also observe that freezing point depression (which tends to be independent of chemical identity) behaviour doesn't dramatically change on whether the solute is charged or not (normalising for realised concentration)... so it would seem that if you dissolved ammonia for instance, it could nicely fit somewhere. John Riemann Soong (talk) 05:24, 15 March 2010 (UTC)

Freezing point depression is caused by the enthalpy differences due to water-solute bonding vs. solute-solute and water-water (ice-type) bonding. As noted, when the water does freeze, it is pretty much pure water (see Fractional freezing) leaving the solute behind. This is true regardless of whether the solute is ionic or molecular in nature. That's because of the way that intermolecular forces work in molecular substances like water. Electrostatic effects from any solute will disturb the crystal lattice of the ice, preventing crystalization. The effects are particular dramatic (and annoying) during recrystallization processes for organic molecules. I remember my time working in an organic synthesis lab, and being frustrated by the fact that it was nearly impossible to get my desired product to crystalize if there was any impurities in it; basically wherever there was two substances present you would always end up with a pale yellow oil rather than nice white crystals, even if the substance was 99% pure. The other 1% would prevent effective crystalization. Bonding in ionic and network covalent substances is very different in this regard; silicate minerals, for example, can show surpising variation due to the presence of trace amounts of interstitial ions in the matrix. But while such interstitial ions work in ionic solids, and in network covalent solids, they do not in molecular solids, due to the way that dipole-dipole and london dispersion forces work in holding such crystal structures together. --Jayron32 18:07, 15 March 2010 (UTC)

Have you read the Clathrate hydrate article? Graeme Bartlett (talk) 09:03, 15 March 2010 (UTC)

Ammonium chloride as a Korean condiment?

I just got some "fried kelp" from a Korean market in Oakland, which I thought I'd enjoy because I like kelp, but it's covered with these colorless crystals that taste really weird. I believe it's ammonium chloride because the only thing I can think of that tastes remotely similar is salty liquorice. Is ammonium chloride used as a condiment in Korean cuisine for things like kelp? If so, what is the Korean name for it? —Keenan Pepper 05:22, 15 March 2010 (UTC)

It could well be ammonium chloride. Is there a list of ingredients on the package that can confirm? If it's a Korean product it may have the corresponding list in Korean. --Kvasir (talk) 06:13, 15 March 2010 (UTC)

No, it's like a deli item made in the market, and there's no ingredients list in English or Korean. All it says is "Fried Kelp". —Keenan Pepper 06:17, 15 March 2010 (UTC)

Hmmm. All the recipes for "Korean fried kelp" that I can find call for sprinkling it with sugar, which of course comes in colorless crystals, so I'm a bit skeptical here. Looie496 (talk) 18:25, 15 March 2010 (UTC)

I think the only way that the OP will be able to satisfy their curiosity ( and now ours ) is to return to the emporium and ask. Should they decline for trade secret reasons, just ask if there Green Card and other documents are in order. Of course, on the other hand if he bought it in the Oaksterdam area of Oakland it might be something completely different. You said it tasted “really weird” Keenan Pepper, did you start feeling really weird as well?

Come to think of it, didn't Leonard Bernstein and Sondheim immortalize this sea vegetable dish in West Side Story ...

Korea, Korea, I just ate some kelp from Korea! And suddenly I found, some Sal Ammoniac around - my fryee ....
--Aspro (talk) 19:09, 15 March 2010 (UTC)

I was thinking of suggesting that for a while, but since you already have and this is the science desk the other alternative is to analyse the crystals in some way. You can go the boring traditional chemistry route of seeing how they interact with various compounds. Perhaps JRS can help here. Or you can use some sort of mass spectrometer. Of course if you don't have access to any of these it's going to cost bucket loads and even if you do the lab supervisor may not appreciate you using them to work out what the crystals in your Korean kelp are (particularly if you tell them you haven't even asked the seller). Thinking of a recent question if you leave these crystals at a crime scene perhaps someone will analyse them for you, but unfortunately you may not be able to tell us the answer for several years in that case. Nil Einne (talk) 21:09, 15 March 2010 (UTC)

Are they perhaps crystals of monosodium glutamate? They taste a bit like salty licorice and are popular in Asian cuisine. --Sean 20:59, 15 March 2010 (UTC)

I certainly hope MSG doesn't taste like salty licorice (salmiakki) or as Salmiyuck as described here. --Kvasir (talk) 05:01, 16 March 2010 (UTC)

Oddball coordinates/geolocation

So I'm looking at a few biology papers. These have geolocation information, but I can't make sense of it. My working hypothesis it's some sort of map-related quadrangle info, but the relevant map is not cited by name (and I just don't knowhow to interpret it anyway):

(1) Hillside above State Highway 79 just south of the bridge over Buffalo Creek NW1/4 sec. 28, T54N, R1W, Pike County, Missouri.

(2)[...] on the east side of an unnamed tributary of Sycamore Creek on the Daube Ranch, NW1/4, NW1/4, SW1/4 sec. 2, T4S, R4E, Johnson County, Southern Oklahoma, Ravia 71/2'quadrangle.

Anybody can help me? Circéus (talk) 11:49, 15 March 2010 (UTC)

These use coordinates from the "township and range" system, used mostly in the American Midwest. See Public Land Survey System#Mechanics for a description of how it works. The entire system is based on a unit of land called a Survey township, which is a square mile of land. The T and R numbers refer to a coordinate system that numbers the townships around a central point defined between two lines, the "principle meridian" (N-S) and the "base line" (E-W). T is the "township number" and R is the "range number". Therefore, NW1/4 sec. 28, T54N, R1W is the Survey Township (square mile) located in the northwest quarter of Sec. 28, 54 squares north of the BL and 1 square W of the PM. Its not as accurate as latitude and longitude would be, but its not really a system for identifying points, its more for dividing land for establishing property boundaries. Each survey township would also be subdivided into plats of individual lots. Public Land Survey System#Mechanics contains pictures that show all the bits I describe here. --Jayron32 12:46, 15 March 2010 (UTC)

Thank you a lot! That really helped! Circéus (talk) 13:20, 15 March 2010 (UTC)

Three things. First, it's the section that's a square mile; the standard township is a square 6 miles on a side, containing 36 sections. Second, a section was often divided into four square lots (1/2 mile on a side), quarter-sections. But these may be further subdivided into smaller squares: what I would expect the "NW1/4, NW1/4, SW1/4" part to mean is the northwest quarter of the northwest quarter of the southwest quarter of the section, thus identifying a specific square that's 1/8 of mile on a side. And third, to avoid any confusion, that word is "principal". --Anonymous, 16:53 UTC, March 15, 2010.

Which of course we have an article on: Principal meridian. Pfly (talk) 09:41, 16 March 2010 (UTC)

gsp

what primetime episode was it where gsp gave tour of his house and said he hated his family? —Preceding unsigned comment added by 67.246.254.35 (talk) 12:12, 15 March 2010 (UTC)

This is the Science reference desk. Perhaps your question should be on the Entertainment desk instead? SteveBaker (talk) 12:26, 15 March 2010 (UTC)

And you might also want to explain who "gsp" is. StuRat (talk) 16:15, 15 March 2010 (UTC)

ufc fighter —Preceding unsigned comment added by 67.246.254.35 (talk) 16:19, 15 March 2010 (UTC)

That would appear to be Georges St-Pierre. -- Coneslayer (talk) 17:12, 15 March 2010 (UTC)

Software for synchronising separately recorded sound to HD video

I recorded three great new bands in Brighton on my HD camcorder, but Radio Reverb had loads of professional microphones and direct lines to the instruments leading to a mixing/CD recording desk, which would presumably exceed even the Dolby 5.1 internal microphones on my camera (which seem to give studio quality sound) and I agreed with them to share the media in the hope of synchronising the audio (presumably to arrive ready mixed on a CD) to my video and then on to blu-ray disk. What software can I purchase, preferably at a reasonable price, to do thus? My computer is a modern dual Pentium dual core 2.4 ghz machine with a reasonable hard drive capacity, which I might upgrade to 2 terabytes. I am running windows XP and would prefer not to upgrade to Vista in case it breaks certain applications I have written in visual basic. My existing Sony software plays the HD video quite well, though the motion is smoother on a proper HD set and blu ray player, or (when down-converted for DVD) a standard DVD and wide-screen cathode ray set, which I do not want to get rid of due to better colour contrast than flat screen HD televisions. Would it be cheaper to get this done by audio-visual professionals instead? filming (great) bands (with their permission) is my hobby and they use their copies as a free promotional tool, I do it to get the footage. —Preceding unsigned comment added by 80.1.80.16 (talk) 13:29, 15 March 2010 (UTC)

Our computing reference desk might be a better place to ask this question. SteveBaker (talk) 16:08, 15 March 2010 (UTC)

Feeding stick insects

How to feed newborn Extatosoma specimens?

They need Rubus or Quercus of course, but how can I persuade them?--87.10.128.186 (talk) 15:40, 15 March 2010 (UTC)

Is this the correct link? And this and this? Bus stop (talk) 15:52, 15 March 2010 (UTC)

Where does one procure newborn Extatosomas? DRosenbach ^{(Talk | Contribs)} 16:31, 15 March 2010 (UTC)

@ Bus stop: Thanks, but those links do not answer my question.

@ DRosenbach: I obtained eggs from an adult female bought one year ago.

But how to convince newborn specimens to eat leaves? --87.16.125.218 (talk) 17:56, 15 March 2010 (UTC)

What the Extatosoma tiaratum article does not say is that they are nocturnal feeders. Providing they have the right food; hunger should do the rest (who do you think gets them to start feeding in the wild). Examine the leaves in the morning. --Aspro (talk) 19:21, 15 March 2010 (UTC)

@ Aspro: Thanks; the problem is that they didn't eat nothing. The "oldest" has two days but unfortunatelly the leaves are still intact. I also tryed giving them a suggestion letting them sniff torn leaves left at the bottom of the tank.--Mparu (talk) 21:08, 15 March 2010 (UTC)

Just a thought. There is a guy on eBay selling Goliath stick insect eggs that suggests “Start feeding Eucalyptus when nymphs then wean onto Bramble as older nymphs then feed a mixture of both.” [9] Maybe your source has a tip on what he first feeds them on. Some people (or rather their bugs) have no problems with feeding at all. Perhaps Eucalyptus contain a chemical trigger that has not yet been recognized and will work on your bugs.--Aspro (talk) 11:10, 16 March 2010 (UTC)

@ Aspro: It could be. I will try to give them Eucalyptus tomorrow, and then we will see. However I observe that they are all still alive. Thanks again. --Mparu (talk) 00:43, 17 March 2010 (UTC)

the 80s

Irrespective of Jayron's comment immediately below, please continue to contribute to this section. Whatever the OP's motivation or intent, there's certainly more to be said here. --Polysylabic Pseudonym (talk) 10:27, 16 March 2010 (UTC)

This has degenerated into an excuse for the OP to editorialize about how boring the lives of people older than he was must have been. Other than an exercise in making his generation feel superior to his elders, it serves no further purpose. The article section titled 1980s#Popular_Culture should adequately lead to answers to the original question. The rest of this discussion is not within the domain of the reference desks. --Jayron32 19:32, 15 March 2010 (UTC)

what did people do in free time back then they didnt have internet wasent it boring —Preceding unsigned comment added by 67.246.254.35 (talk) 16:20, 15 March 2010 (UTC)

Believe it or not, people can interact without the internet, and in fact did so. There were sporting events before espn.com, facebook did not invent the concept of friends, and music existed before itunes. Googlemeister (talk) 16:24, 15 March 2010 (UTC)

this is not related to freinds, its about fun. in the 90s i was bored outo my mind. —Preceding unsigned comment added by 67.246.254.35 (talk) 16:27, 15 March 2010 (UTC)

Per WP:WHAAOE, we have a section and several related sub-articles about popular culture and lifestyles in the 1980s. Film, television, music, sports, toys, art, education, and so on, all existed in the 1980s. Notably, in light of your comparison to "zoning out" on the internet during periods of great boredom, the 1980s saw the mainstream rise of cable television, including 24 hour programming (a new and exciting cultural transition!) Nimur (talk) 16:33, 15 March 2010 (UTC)

Nobody has mentioned video games! At Wikipedia! For shame. Comet Tuttle (talk) 16:57, 15 March 2010 (UTC)

yea i watched tv and played the lame video games in the 90s but i was still bored outta my mind —Preceding unsigned comment added by Thekiller35789 (talk • contribs) 17:07, 15 March 2010 (UTC)

Maybe you should have played the good ones. BBSes were fun, too. -- Coneslayer (talk) 17:11, 15 March 2010 (UTC)

Skateboarding as a popular sport developed in the 80's. Before that (in the 70s), boards were plastic with steel wheels and you couldn't do much more than slalom through some cones or something else rather lame. Some kids got into other passing fads like breakdancing or trick BMX stuff. Of those, skateboarding is the only one that I've noticed still continues with the teenagers today - at least I always see a few kids in my class bring in their boards and they are always amazed when I reference some board trick while explaining some concept in class. They can't imagine that a 40-year-old fart actually knows something about their sport. -- kainaw™ 17:33, 15 March 2010 (UTC)

Just to clarify... I am answering what people outside of the California coast did. By the time skateboarding became nationally popular in the 80's, they had been doing tricks in places like Santa Monica for nearly 10 years. Don't want to get into a debate about local interests vs. national interests. Might as well argue about when that pathetic "Valley Girl" talk spread across the country (and I like still like totally hear students like using that talk and stuff). -- kainaw™ 17:38, 15 March 2010 (UTC)

There are people that spend a lot of time being bored in the present day, too. Nothing has really changed in that respect. --Tango (talk) 17:41, 15 March 2010 (UTC)

When I was a kid in the late 70's/early 80's I played video games at arcades, such as Space Invaders, Centipede, Pac Man, Galaga, and Tempest (my fav). You may say they are "lame", but that's only in comparison with the games we have now. Those games were exciting compared with what came before (pinball). The games you currently play will also seem lame to future generations ("Aw man, this isn't even 3D, how lame !"). StuRat (talk) 17:43, 15 March 2010 (UTC)

"You mean you have to use your hands? That's like a baby's toy!" Nimur (talk) 18:12, 15 March 2010 (UTC)

Before the very, very late 90's, life was unbearably boring. So much so that a recent Economist article on the state of television mentioned that you could pretty much put anything on TV and people would watch it, out of sheer boredom. Therefore, if none of the networks were running anything interesting, then they could all still get a lot of advertising money, since millions were still tuning in. The only problem with running totally boring content was if another network was running something marginally less boring. But the bar wasn't very high: people were bored out of their MINDS. Now, fast-foward to 2010. These days, the bar for television is very high. People will NOT put up with something totally boring, they'll just turn off the TV and go on the Internet and find something a ton more interesting for them. The bar for television is REALLY high, since people aren't forced to watch whatever's on out of sheer boredom. Actually, the setting of the sun on newspapers is the same: people used to read the daily paper at some point during the day out of SHEER BOREDOM. They would have literally nothing better to do than read a whole article on something they're not even remotely interested in, just because they've read all the articles already that they find interesting in the least. The problem was when people had more time, they would run out of EVERY article in the paper, people, get this, I am NOT making this up: people used to read the obituaries for their city. ALL OF THEM (the ones with small articles). Every day. That's how bored out of their mind they were. The problem was most excarbated, of course, on Saturday and Sunday, where if there were just a daily paper, they would be through with it by 1 PM. Then what do they do? So Newspapers made Sunday editions that were vastly larger, included comics for the bored kids, and so on. Basically, to sum it up for you, when people weren't at work, at school, or some special event, they were bored out of their minds. They would do just about anything, up to and including sitting down with a game of Monopoly or Scrabble, just to get through the evening. That's a fact. 82.113.121.99 (talk) 17:55, 15 March 2010 (UTC)

The Pet Shop Boys wrote a song with the lines "we were never bored/because we were never being boring", which is supposed to be a quote from a 1920s socialite (sorry, searched Wikiquote but couldn't find the original). I can't remember being bored after I left home when I was 18: the world was too full of exciting things for me to be bored! --TammyMoet (talk) 19:22, 15 March 2010 (UTC)

Nobody has mentioned books, libraries or hobbies yet. Can you provide a link for that Economist article? AlmostReadytoFly (talk) 09:22, 16 March 2010 (UTC)

why the hell was this archived this was interesting now its ruined someone un-archive it please —Preceding unsigned comment added by Thekiller35789 (talk • contribs) 20:08, 15 March 2010 (UTC)

to jayron- im not trying point out how "boring the lives of people older than he was must have been" nor am i trying to "make my generation feel superior to his elders". i am a student of history and i like the 80s and wish i could have lived then. i am interested in how people passed the time back then. please do not mistake my motives. i like to hear about the past. the article you linked dosent help unfortunately. to whoever has been archiving it-please stop. i like hearing other peoples answers.

I was born in the '70's so my childhood was in the '80s. '83 was my favourite year. Oh, and I'm Australian - my comments relate to the 80s in Canberra, Australia. Note that no shops (but a few petrol stations) were open Sundays, and on most weekdays places closed at 5pm.

As a young child dinner and getting ready for bed took from about 5:30. So only 2 and a half hours to fill. That was a walk to a friend's house, then riding our bikes or skateboards or roller skates to a local park, or playing on a computer or console. Or spending our money in a computer game arcade. On weekends: bike riding, visiting friends, playing kids games.

As an older child (say 10 years or so), there was still loads to keep from boredom. Rollerskating, rollerdisco, waterslides, street cricket, playgrounds where you were allowed to get hurt! (back then we had a 5 metre high tarzan swing, with a 3m high tiered platfrom from which to jump). The computers were better. I and a few friends could catch a bus to a swimming pool, ice skating rink, roller rink (actually that was a short walk skate away). Music on tape on a walkman, making mixtapes to play on the walkman, nintendo game and watch (or were they later?). For quiet or rainy afternoons or "can't be bothered going outside" there were board games, cards, books.

Young teenager much the same as above, but more time spent shopping - and more money to spend. A good book could waste an entire Sunday, with the Saturday spent on homework, and any of the above activities - and my parents had a swimming pool put in, so swimming more.

Then I ran out of 1980s. In all of the above, the only worthwhile TV was a few docos and educational TV programmes on ABC (the Australian Broadcasting Commission), a couple of cartoons, and the friday night movie.

There was far too much to do to be bored if you didn't want to be. Sure you could bore yourself to death with TV (until station close - the test pattern was less dull than the normal programming). You could sit around saying "nothing to do", but in warm weather there were a thousand things to do, bike, skates, ice skates, swimming, shopping, reading, board games, visiting friends and playing with their stuff. In winter, same but the day were shorter, there was more hot chocolate, there was at least one visit to the snow for a weekend, less swimming, less iceskating, less bike riding. More rollerskating, more reading, more board games, more card games. --Polysylabic Pseudonym (talk) 10:26, 16 March 2010 (UTC)

suicide

why is it thought that young people have a high rate of suicide? isint the average age like 68? —Preceding unsigned comment added by Thekiller35789 (talk • contribs) 16:25, 15 March 2010 (UTC)

Perhaps successful suicide follows multiple attempts. DRosenbach ^{(Talk | Contribs)} 16:29, 15 March 2010 (UTC)

i dont think so, if u fail u will prob be crippled —Preceding unsigned comment added by Thekiller35789 (talk • contribs) 16:37, 15 March 2010 (UTC)

That would depend on the method attempted. Googlemeister (talk) 16:41, 15 March 2010 (UTC)

Instead of speculating, why don't you check some statistics? Fast Stats from the Center for Disease Control is a good brief overview, and it links to a detailed statistical report, National Vital Statistics Report, as well as a Suicide Trends among Youths report, a Trends by Age Group report; and if you want more, here is a Google search query for more. Nimur (talk) 16:50, 15 March 2010 (UTC)

(ec) The original poster is asking why it's thought that young people have a high rate of suicide, despite the facts. He appears to be correct about the facts; this page from the WHO has links to PDF files showing the rates by gender, and by gender and age, for lots and lots of countries. Here are the rates (both genders) per 100,000 in the US:

Age 5-14:    0.7
Age 15-24:  10.0
Age 25-34:  12.4
Age 35-44:  14.9
Age 45-54:  16.4
Age 55-64:  13.8
Age 65-74:  12.5
Age 75+:    16.8

So, young people have a lower suicide rate than older people, at least in the US. Our article teenage suicide in the United States does not mention this (although it will shortly) and does not talk about the gap between the facts and perception. This is WP:OR but I will guess that youth suicide is thought of as more sad or tragic than adult suicide, and heavy media coverage might lead people to believe there is some sort of epidemic underway. Just a guess. Comet Tuttle (talk) 16:56, 15 March 2010 (UTC)

An important missing bit of data is evidence that suicide really is popularly thought that young people have a higher rate of suicide. DMacks (talk) 17:00, 15 March 2010 (UTC)

Googling teen suicide epidemic yields 62,000 hits, which is anecdotal, and some of the hits are on local "epidemics", but it supports the premise. Comet Tuttle (talk) 17:11, 15 March 2010 (UTC)

Exactly. So "why is it thought" (emphasis mine) might be directly answered from them. Gotta be careful to avoid a self-fulfilling mediafest though (OTOH, that may really be the reason?). Just because teens to it and it's reported as such, the stories I usually see focus on teen-suicide as a symptom/involved with other teen issues. Not "only teens do it" but "teens do it for teen reasons"--the bias is in choice of separate topics, not necessarily ignoring an included subset of the topic. None of which addresses why non-teen groups are not discussed as much, right back to the initial question:( DMacks (talk) 17:22, 15 March 2010 (UTC)

Come on people, the answer is obvious. The rates of young and old are similar, but suicide is a top cause of death among young people and way down in the list for 40-70 yr olds, even though the per capita rates are similar. alteripse (talk) 17:10, 15 March 2010 (UTC)

That's probably a factor, yes. Comet Tuttle (talk) 17:11, 15 March 2010 (UTC)

In addition, those statistics are I'm guessing successful suicides and don't include attempted suicides. Suicides may of course be a cry for help particularly among teens and may not be truly intended so succeed although in some cases, e.g. if Panadol or weedkiller is used, the person may still die even if they later regret it. While these may not seem as serious a problem, they are still a concern. In addition even if they are more serious about it (and ultimately it's a continuum anyway), teens are generally less experienced and have access to less resources and are more likely to have some dependence on and close connection to parents or guardians, so teens attempting suicide may be more likely to be rescued in time compared to adults. In other words, even if fewer teens successfully commit suicide, there may still be more attempted suicides from teenagers. Nil Einne (talk) 18:28, 15 March 2010 (UTC)

the The rates of young and old are NOT similar. old is much more —Preceding unsigned comment added by Thekiller35789 (talk • contribs) 17:23, 15 March 2010 (UTC)

Are you sure? from the table above we have for the US (Age 25-34: 12.4) and (Age 65-74: 12.5). Icall that similar. Dauto (talk) 17:55, 15 March 2010 (UTC)

The OP is I believe 19 so 45-54 may be old to them. Nil Einne (talk) 18:28, 15 March 2010 (UTC)

Something that's always bothered me is that the term "suicide" is used to include two entirely different things. One, as in most teen suicides, is choosing to end a life that would otherwise continue normally. The other, as in most elderly suicides, is choosing to end a life that will soon end anyway, often in extreme pain, from a terminal disease. StuRat (talk) 17:30, 15 March 2010 (UTC)

It's still suicide though. You can argue mental pain vs. physical pain, but in the end taking your life is still technically suicide. — The Hand That Feeds You:^Bite 19:19, 15 March 2010 (UTC)

It is, in English, but that's just semantics. I wonder if other languages have different terms for those two concepts. For example, ritualized suicides may have different names, such as "seppuku" (hara-kiri) in Japanese. StuRat (talk) 19:49, 15 March 2010 (UTC)

Regardless clearly the idea there are two "entirely" different things is somewhat simplistic. At the extreme edges, perhaps but it's much more of a continuum and in fact even that's too simplistic since it isn't a 1 dimensional thing. For example if someone who is diagnosed with cancer with an expected average lifespan of 5 years, but the possibility of living significantly longer if treatment is successful and the expectation that they will still be able to live a resonably painfree life for perhaps the next 3 years commits can't be said to be having their live end "soon anyway". If you're resonably young and have beaten cancer once but suffer a relapse, there's a resonable chance you may beat it again, although you're always likely to be living with cancer and the coming weeks and months are probably going to be painful whatever happens and at the end, you may die anyway. Someone who has just commit a serious crime, in a country without the death penalty live will go on, but it's hardly going to be normal and they could be in prison for a long stretch of time. Someone on death row who commits suicide is probably going to die soon (although there's still the possibility of clemency). Someone who owes a lot of money to a loan shark which they can't pay may not necessarily expect to die, but may expect to find live very unpleasant or they may simply not really know what to expect. For an extremely depressed teenager or whatever (e.g. someone who's just lost a partner) it may seem to an outsider that for them live will go on and should even eventually start to become better, but the problem is often while perhaps they kind of realise that in the back of their minds, it's not something they can really 'understand' and most likely in some ways to them it seems life will always be this depressing, unbearable existance (some may realise their life is not going to end soon which may give them an impetus to commit suicide but equally I expect some just can't/don't think about that). Of course there are also who commit suicide for other reasons (e.g. to make a point, some sort of socially expected ritual, because they think they'll transcend to become aliens) but we aren't really discussing those I guess Nil Einne (talk) 20:55, 15 March 2010 (UTC)

Young people in industrialized countries die of accidents in the traffic and of suicide and very few from illnesses, the chance that that happens is low because most of us get old. The percentage of suicide as cause of death for young people is high. The low number of people dieing at young age multiplied with the the high percentage gives the moderate number quoted above. --Stone (talk) 19:10, 15 March 2010 (UTC)

... I really can't parse what you're saying here. — The Hand That Feeds You:^Bite 19:20, 15 March 2010 (UTC)

I think he/she is basically repeating what Alteripse said Nil Einne (talk) 20:56, 15 March 2010 (UTC)

A.I. Apollo Program

Imagine the USA decided to spend billions on creating a self-aware artificial intelligence. Given a huge commitment of labor and resources how long would it take from today to reach that result?

Before you say we don't have the technology or quote Raymond Kurzweil or Moore's law keep in mind the Moore's Law is not a hard rule but rather a benchmark manufacturers aim for. Given subsidies we could surely accelerate the growth rate of processing power and perhaps even leapfrog far ahead given some advanced research. TheFutureAwaits (talk) 19:28, 15 March 2010 (UTC)

I don't think any amount of time or money would do, because we lack even the theory as to how to make a machine self-aware (versus making it pretend to be, which we can do now). StuRat (talk) 19:40, 15 March 2010 (UTC)

(edit conflict) Its likely an unanswerable question until you define your parameters for what you mean by Artificial intelligence. The term is extremely broad; however truly sentient machines would require a complete fundemental change in the way we currently construct hardware and software, especially for a machine that would pass the Turing test. It isn't a question of simply making faster and faster computers that can do more complex calculations. All modern computers are fundementally still Turing machines, that is with an arbitrarily large memory and enough time, every single computer, from the ENIAC to your cell phone, could all perform the exact same tasks. Any computer can model sentient responses to stimuli, but they do it in a non-sentient way. To design a sentient machine would require starting from scratch, some interesting developments are happening in the way of Artificial neural network, either virtual or actual hardware-based ones, since they actually behave the way real brains do, and thus stand the best chance of replicating actual sentience. --Jayron32 19:42, 15 March 2010 (UTC)

As far as I've read, there is no known reason to believe that a hardware change is required for sentient machines besides the ongoing increase in computing capacity.

There is no evidence that our own sentience or the primitive self awareness of some other animals isn't based on deterministic, physical phenomena. APL (talk) 21:45, 15 March 2010 (UTC)

(edit conflict) (I knew this would happen)

I think that right now, the biggest hurdle in creating a self-aware AI is that we would need to understand how self awareness works. Right now, we have only the vaguest idea how the human brain works, and if we want to replicate those abilities, we would first need to know how our brain works in detail. This is something we have been working on for a long time and it is very hard to gauge our progress. We simply do not have a good answer for this question. Googlemeister (talk) 19:44, 15 March 2010 (UTC)

(ec) The real problem is, as far as I understand it, is that we probably don't know the scope of the problem. This isn't a "simple" engineering problem where you scale up some existing things, with a large margin of error for unknown unknowns. We don't even know what the end-situation should look like—how we could make something that was "self-aware" or not. We don't really know how that would go. Scaling up existing A.I. work does not (as far as I know) look like it would create something "self-aware" in any real sense (whatever that even means!). If we defined our outcome by some kind of more obvious metric (calculations per second; ability to play chess better than a human; ability to read and contribute to Wikipedia as good as some of our better contributors), we could probably come up with a reasonable estimate. But "self-awareness" is a vague concept at best when applied to computational thinking.

To take another historical project as a point of comparison, the Manhattan Project did not really begin until the basic engineering constraints of the problem were pretty well understood. It was still a gamble and required discovering a lot of new things in a very small amount of time, but the theoretical basis for knowing what might be possible was pretty well understood. I'm not sure A.I. work is quite at that stage yet—or, put another way, I'm not sure we understand the cognitive functioning of biological brains well enough to make "artificial" ones yet that function similarly. Perhaps someone more informed about the current state of things would have more to add on that specifically. --Mr.98 (talk) 19:45, 15 March 2010 (UTC)

all of the posters above are quite wrong. Granted, no amount of money would bring about self-aware AI by tomorrow evening at 8 PM -- not even if you were to spend say $60 trillion on it, which is one year's of the world's GDP. In theory the entire world could somehow borrow a year's worth of GDP, ie $60 trillion. But even if the world did do that, and put the entire money into self-aware AI, it would not happen by 8 PM tomorrow. You just can't move money into project at that scale that fast. On the other hand, if the world were to borrow 1 year of it's GDP and put it all into creating self-aware AI as fast as possible, then I think it would be done within a matter of months with that money. Probably the way to do it would be to split the 60 trillion into bets, different avenues, and even if you make 1000 such bets, each bet gets $60 billion funding. Now, just off of the top of my head I can list about a dozen of these bets, each of which I wouldn't be surprised at succeeding. (if you must know they include:

• starting from the now sequenced human genome, ie analyze it and extract from it. In this scenario you spend your $60 billion (or more, if there are fewer bets) on human brain power, the best in the world, to try to reverse engineer the roughly 1 cd-rom of data. I think $60 billion might be woefully inadequate to properly reverse engineer it, but who knows; it just might be. I consider this scenario unlikely to succeed.
• starting with more precise brain imaging, ie spend $30 billion on scanning and imaging a brain and $30 billion on hardware that will run it at 1/1,000,000th realtime speed. Bam! A consciousness, albeit it will be pretty trippy for it, considering a year goes by every 30 seconds it's conscious.
• do highyl parallel molecular/DNA computing to do highly parallel computing. I have no idea how you get intelligence out of it, but the idea is if intelligence evolved in the real world, then if you spend $60 billion on goo that does highly parallel _________, maybe you can induce and brute-force an evolution of an intelligence. I don't know if this one would even be considered "artificial" though -- why isn't it just real intelligence?
• For $60 billion, you can probably get around the proscription on certain human experiments, and somehow reverse engineer an actual human not with brain imaging, but layer by layer peeling away neurons however compensating for them electronically at each step. Actually $60 billion is woefully inadequate for this proposal, probably more like $1 trillion would let you do it.

) That's just off of the top of my head. Basically, it's just a question of money. Even the bets I just listed aren't very sure with $60 billion, and if you start with 1 year of the world's GDP, you can only make a thousand such bets. If, however, you a hundred year's of the current world's GDP at your disposal, then you can make a thousand such bets funded at $6 trillion each (or some of them funded more). Now we're really talking. If you had that much money for this project, you could probably be 100% confident of achieving the goal within 9 months.

But why would the world want to put itself into dept at 100 times it's annual GDP to produce, in addition to the six point eight billion people who can currently convince you that they are conscious and awake, cognizant of their surroundings, etc, one non-person who can convince you that it is conscious and awake, cognizant of its surroundings, etc.???

I mean it's an interesting result and all, but it's already doing something that we KNOW is possible given the physical laws of the universe and, oh, about 3 pounds (the weight of the human brain) and less than a CD-ROM worth of source code with some mild compression. (The human genome).

I mean, you're not even going to get something that is as small or as useful as the human brain. You spend 100 times the world's GDP, and get a building-sized supercomputer capable of basically the same function we have 6.8 billion biological specimens of. Meanwhile, the world is probably not going to live down the effects of the intellectual orgy you've gotten it into maybe for 200 hundred years (optimistic) or maybe it will simply never reach the level it would have if you hadn't entered it into such a crushing debt burdon. Basically, the reason we're not spending even as much as the moon missions on reproducing consciousness, a known possibility, is: why would we? 82.113.121.99 (talk) 20:21, 15 March 2010 (UTC)

. Comet Tuttle (talk) 20:26, 15 March 2010 (UTC)

You don't need a citation to point out that if something exists then it is possible. More specifically, you would need a citation if what I just said (I'm the same poster, maybe my IP has changed slightly) either could or could not be the case. But it is not a possibility that it is not the case: you could not read, a la the Goedel incompleteness theorem, a published proof that it is impossible for a body of finite mass to be self-conscious. Just imagine for example the idea that we would abandon the idea of ever making artificial AI, because there is now a proof floating about that, for any such AI that can exist, it must be infinite in mass. A mathematical proof like that. Just imagine it. You can't imagine it, because it is preposterous and absurd, given that we know that three pounds of stuff can do it, and we know it six billion times over. So the idea that you would need a citation, whereas the alternative state of affairs is prima facie preposterous, is absurd. 82.113.106.100 (talk) 20:49, 15 March 2010 (UTC)

It is not absurd to ask for references on a reference desk, particularly when you invent a bunch of numbers to support your points. Comet Tuttle (talk) 22:23, 15 March 2010 (UTC)

fine, what numbers do you need referenced that aren't obvious to you or common knowledge? --82.113.106.92 (talk) 23:08, 16 March 2010 (UTC)

Personally, I think the final answer will be a proof that we are not "conscious" in any special way after all...that all sufficiently complex systems have a rudimentary self-awareness. However, I believe that raw complexity is the solution here. I suspect (without proof) that if you built a computer with comparable complexity to the human brain - had it run a neural network simulation at comparable speed to the brain - with cameras and microphones hooked up to it appropriately - and took it through the same kinds of developmental and learning processes that a baby goes through in the womb and for the first half dozen years of life - then there is a good chance that it would exhibit all of the properties of a conscious human. Sadly, we're perhaps 50 years of solid Moore's law expansion away from being able to do that. However, the odds are extremely high that if we did that - and it worked - then we'd learn nothing whatever of value from doing this since we don't have a way to prove that a being truly is "conscious" - or even a practical definition of what that means - and the likely complexity of a computer that would exhibit conscious-like behavior would probably be comparable to the complexity of the brain of a "higher animal" - and therefore as far beyond our ability to analyse as a real human brain. SteveBaker (talk) 21:30, 15 March 2010 (UTC)

I concur with the others who say that there's an immense theory gap. No amount of effort or money will help us if we don't know precisely what intelligence is in the first place. If NASA didn't have a handle on where the moon was, they couldn't have made it to the moon with a rocket that was 100 times as efficient. We can make computers succeed at some tasks that intelligence can also solve, but we don't know how people solve those tasks in the first place, so we don't even know whether we've made progress or not. Paul Stansifer 22:31, 15 March 2010 (UTC)

I just want to clarify that just because there is a large theory gap does not mean it is not possible to throw a lot of money at it and get results. It just means that estimating the amount of money necessary is probably not possible ahead of time. It may be, as SteveBaker posits, that the theory gap is illusory. But we don't know have great ways to know that at the moment. There is a difference between saying, "we can't do this" and "we don't know how much it would cost to do this." I think the latter is true and the former is probably false.

Just as a point of comparison, we've thrown a lot of money at cancer research in the last century. It turns out to be a very non-trivial problem—a different sort of medical problem than, say, finding a vaccine for polio, which took only a couple of decades to develop after real money was put behind it. This is a comment on the apparent nature of the problem, not the nature of science itself. Cancer is hard. Is A.I. hard? Opinions differ on this. If the answer is "yes" then it means that it's possible that huge amounts of money won't do much other than tell you exactly why it is hard. If the answer is "no" then huge amounts of money can get rapid results. A lot of problems are obviously in between these two extremes. The thing is, I don't think we know where self-aware A.I. falls in this spectrum. --Mr.98 (talk) 22:41, 15 March 2010 (UTC)

If NASA sent up enough rockets they would have found the moon eventually! Seriously, there are parts of the problem that could be worked on in the hopes that other parts would fall into place later. Specifically large computers. (Would throwing more money at computer engineering significantly increase the rate of progress? It's already a well funded industry.) Also, with an unlimited budget some vast parallel supercomputers could begin work on the type of experiment that Steve describes above. (And other proposed types of emergance intelligence.) If nothing else, dead-ends could be eliminated from future consideration.

Of course, even if they didn't know where it was, NASA would have recognized the moon when they landed on it. Would we recognize a sentient AI if we saw one? (Is Commander Data sentient? He'd never in a million years pass a rigorous Turing test. Neither would HAL9000.) APL (talk) 22:52, 15 March 2010 (UTC)

The question is not, "would throwing money at it get some kind of results." It surely would. The question is, "would a crash program work like Apollo or would it work like the War on Cancer?" Or, more specifically, could we possibly know ahead of time? (And a secondary question is, "is this the best thing to be spending resources on?", which is not a question that science alone can answer.) --Mr.98 (talk) 22:55, 15 March 2010 (UTC)

What made cancer difficult was that it turned out not to be just one disease with one cause - but hundreds of separate diseases with hundreds of separate causes. The push to cure it did an amazing amount of good. There are now dozens of cancers that we can cure - there are dozens more that we can detect early and at least have a good shot at curing - and dozens and dozens of causes that we have eliminated from our environment. The moon shot was just about the opposite of that. It was a single clear goal with a small set of distinct problems to resolve to get there. The quest for AI is yet a different problem - we don't even really know what the question is yet - and we wouldn't recognize the answer if we solved it tomorrow. How would we know if the Internet was sentient? How do we know that it isn't? That puts it a long way from getting a man on the moon - and probably further out of reach than curing all possible cancers. But we honestly don't know. It's perfectly possible that we already have machines of sufficient complexity that they are already "conscious". It's also perfectly possible that there is really no such phenomenon. The answer to this question is "We don't know - and we don't even know why we don't know." SteveBaker (talk) 23:16, 15 March 2010 (UTC)

If successful AI means anything, a minimum is an ability to carry on a coherent natural-language conversation. And the simple fact is that nobody currently knows how to build a machine that can do that, for any amount of money. Looie496 (talk) 01:56, 16 March 2010 (UTC)

The problem is in part that we don't really know how people do that, and people seem quite exceptional in their ability to do that. I think one of the main A.I. problems in general is that human language and abstract reasoning capabilities are pretty off-the-map. It's what we do; it took millions of years of evolution. Until we figure out how it works (and from what I've read, it's not just "add more neurons and it'll spontaneously emerge"—things are a lot more specialized and complicated than that), we're going to have a hard time making a machine do it well. Doesn't mean it's impossible... just that we're not really sure how complicated a problem it is, even though we've had a lot of people working on it for quite some time now. We'll probably find an answer—it's not magic—but it's not clear that just throwing money at it alone is going to turn up a shortcut. --Mr.98 (talk) 02:22, 16 March 2010 (UTC)

Sneezing and hair length

A general wonderment. If I measured the distance my head moves when I sneeze, and the time it takes for my hair to land back down on my head, could I calculate the length of my hair (assuming my hair grows pretty straight). If so, any ideas what I'd need? Would I have to use things like gravity formulas and calculating air resistance, or is there a nice simple way with a bit of maths and angles? Edit: Actually thinking about it your head doesn't go straight down when you sneeze so there might need to be some force directiony things to that I did in maths a long time ago. —Preceding unsigned comment added by Jimothyjim (talk • contribs) 21:20, 15 March 2010 (UTC)

Well, if you had good numbers for the mass of your head, the elasticity of your neck, the velocity and mass of material ejected during the sneeze, the shape of your scalp and the springyness, density and cross-sectional area of the hairs - then a mathematical model (probably a differential equation of some kind due to the distributed nature of mass along the length of the hairs and the curvature of the scalp) could be used to calculate the hair length from the bounce time. But ask yourself this: What are the error bars like? I could believe that you could measure the bounce time accurate to 10% - but there would be at least a 10% error bar on each of the other numbers - some of them possibly more like a 50% error. When you multiply out all of those sources of error and take an honest look at the size of the total error in the length estimation you'd get as a result, the answer would be something like "Between 5cm and 50cm"...which, to be honest, is something you already knew! So it's certainly possible - but without good data, the result isn't much use. SteveBaker (talk) 23:07, 15 March 2010 (UTC)

You might start by assuming a spherical head and one strand of hair. 24.12.190.7 (talk) 03:47, 16 March 2010 (UTC)

Well, what if you made a few assumptions like, momentum form things expelled from the nose being negligble and things like that, and concetrated on the more important things like the elasticity/snap back of the neck after the sneeze and the hair mass and such alike, and recorded the sneeze with a slow-mo video camera so you could accurately get the times and distances via a computerJimothyjim (talk) 22:12, 16 March 2010 (UTC)

As Steve implied above, there are just too many variables that cannot be measured accurately. Hair behaves very differently in different atmospheric conditions, and even more variation arises from the length of time since you last washed it. Dbfirs 09:36, 16 March 2010 (UTC)

If you have all of that fancy computer measuring stuff - why not just use it to measure the length of the hair? SteveBaker (talk) 12:51, 16 March 2010 (UTC)

Surely thinks like atmosphere can't make _that_ much difference, and you could use controlled conditions as much as possible with everything. Also I could use a ruler to measure my hair without all the fancy computer stuff, but thats not the point :P Jimothyjim (talk) 22:11, 16 March 2010 (UTC)

If I were to take some strands of hair in one hand and an anvil in the other and dropped them simultaneously - don't you think the anvil might crush my foot to a mushy pulp quite a bit before the hairs reached the ground? Yeah! It matters! But suppose we try to reduce the problem to the barest minimum: If you can measure the period of swing of the hair once it's been perturbed from equilibrium - then you'd be reducing the problem to (essentially) figuring out the period of a pendulum where the mass and air resistance was evenly distributed along the length of the hair, then maybe you could use that to figure out the length...but the whole sneezing thing is really just a gigantic complicating and error-introducing factor which you'd be eliminating by taking the 'pendulum' approach. Doubtless someone here could tell us the formula for determining the period of a pendulum who's mass is evenly distributed along its length - and my best guess is that wouldn't depend on the mass - which is good because it's an error-prone unknown. But you're definitely going to need to know the air resistance - and that's very non-trivial for a mass of hairs with turbulance induced in the airflow between them and who-knows-what other weird effects going on. SteveBaker (talk) 01:27, 17 March 2010 (UTC)

What's wrong with using a ruler? You'll be using a ruler to take some of those measurements and angle for your fancy calculation anyway. --Kvasir (talk) 03:10, 17 March 2010 (UTC)

March 16

3,3-Dimethylmalic acid

I'm looking for a reference for the acid dissociation constants for 3,3-Dimethylmalic acid. I checked my usual source, the CRC, which didn't have it. I did a google search, where I only found a little bit about the compound at all, and nothing about the acid constant (here, for example). I have access to a lot of journals at my university, so any citation would be welcome. Thanks. Buddy431 (talk) 01:21, 16 March 2010 (UTC)

SciFinder reports a value of the pKa as 3.41±0.15 (no information on the second or further deprotonations). This was calculated using ACD/Labs Software V8.14. The 7 references that SciFinder has for this compound (CAS Registry Number: 73522-92-6) don't appear to be studying the physical properties. 24.150.18.30 (talk) 01:51, 16 March 2010 (UTC)

since it is a fairly simple compound, I think that the calculated pKa would be fairly trustworthy. Anyone have any other opinions on ACD predictions?. 24.150.18.30 (talk) 01:51, 16 March 2010 (UTC)

Thanks for the quick response. That's better then nothing, I guess. I'd rather have experimental results, and I'd really like the second dissociation constant, if possible. Buddy431 (talk) 02:02, 16 March 2010 (UTC)

Any reason to believe the methyl groups would change the pKas? AFAIK intramolecular hydrogen-bond stabilisation increases the acidity and I don't see how the methyl groups would interfere (if anything it would enhance). John Riemann Soong (talk) 06:24, 17 March 2010 (UTC)

Squirrel identification

Hi, can anybody identify either of these two squirrels for me. It should be easy since they only get a few species. I'll add them to the species articles upon response, thanks in advance. --Benjamint 06:00, 16 March 2010 (UTC)

• 
  Taken at the base of Bukit Timah hill, Singapore
• 

It looks at first shot to be a Plantain squirrel, (Callosciurus notatus), another pic [10] Richard Avery (talk) 08:33, 16 March 2010 (UTC)

So I guess by elimination the other is a Slender Squirrel? I'll go ahead and change it. Thanks --Benjamint 05:29, 17 March 2010 (UTC)

Compression of purely digitally animated films

Consider a purely digitally animated film such as shrek or Finding Nemo. I wonder what the difference is between the file size of the film (stored in some sufficiently-high-resolution pixel-based format) and the size of the original dataset used by the software to render the film (in which the characters are described as a set of coordinates that presumably need to be stored only once, their movements can be described using instructions like "move a certain joint by a certain amount of degrees"). 83.134.160.19 (talk) 06:44, 16 March 2010 (UTC)

Useful stats can be gathered from open movie projects such as Elephants Dream and Big Buck Bunny. For Elephants Dream it's available at 1080p resolution at 815MB for a 11 minute film, compressed with MPEG4. In contrast the production files (texture, models, animation, sound, etc.) are split across 2 DVD's. I do not have an exact figure but 2 DVD's are about 9GB worth of data. For Big Buck Bunny the 1080p MPEG4 compressed version is 890MB, but the entire studio backup is over 200GB. --antilived^{T | C | G} 07:01, 16 March 2010 (UTC)

Thanks! I'm surprised the original data is actually larger than the film itself. I would have expected the opposite. 83.134.160.19 (talk) 07:08, 16 March 2010 (UTC)

The uncompressed number for Elephant's dream is 246 Gbytes. 1080p format is 1920x1080 pixels at 60 frames per second and at (as a minimum) 3 bytes per pixel - so 1920x1080x60x3x11x60= 246,343,680,000 bytes. If they used high-dynamic-range rendering, then it might be as much as four times that amount. Adding in the models, textures, etc is really cheating because that would include the means for MAKING the movie - not the movie itself. Anyway - that yields a fairly typical MPEG compression ratio of about 300:1. SteveBaker (talk) 12:48, 16 March 2010 (UTC)

Would they really render at 60 fps? Blu-ray Disc only supports 1080p at 24–25 fps, and according to Digital_cinema#Digital_projection, the 2K projection spec is 48 fps max. (And I suspect that 24 fps is far more common.) -- Coneslayer (talk) 12:57, 16 March 2010 (UTC)

a question about light

can we move an object using light... —Preceding unsigned comment added by Avinashmani (talk • contribs) 09:12, 16 March 2010 (UTC)

Yes. solar sail, radiation pressure 157.193.173.205 (talk) 09:22, 16 March 2010 (UTC)

Also Beam-powered propulsion, but note that some of the craft in that article have only been proposed, not successfully built. AlmostReadytoFly (talk) 12:18, 16 March 2010 (UTC)

Interesting article, I remember hearing about a team trying to develop a sustainable idea for a space elevator using a similar concept using a ground based laser as a power source for the elevator on the cable. Regards, --—Cyclonenim | Chat  13:19, 16 March 2010 (UTC)

That wasn't moving the object directly using light - it was using solar panels, lit by the laser to charge batteries that the motors would use to propel the robot up the cable. That's not really the same thing. SteveBaker (talk) 13:56, 16 March 2010 (UTC)

For something a little more abstract, see optogenetics. Nice demonstration video here. N.B. The OP doesn't specifically state that light is the source of energy of movement, just that an object can be moved by light. --Mark PEA (talk) 17:58, 16 March 2010 (UTC)

I read a science book when I was a kid that explained how to make some kind of little pinwheel thing with four blades that were shiny on one side and black on the other. You'd put it in a glass jar in the sunlight and it would spin (I think because of uneven heating). Either Wikipedia doesn't have an article on this thing, or, more likely, I'm not able to come up with the right name for it. —Bkell (talk) 18:15, 16 March 2010 (UTC)

Crookes radiometer. Compare to Nichols radiometer, which is what Crookes thought was happening. DMacks (talk) 18:59, 16 March 2010 (UTC)

Those things are always being sold as gizmo's that are rotated by photon pressure - but it's not true. The problem is that there is not a solid vacuum inside the globe and the air resistance (and probably the friction on the central spindle) is more than enough to overcome the photon pressure. The reason they spin when left in sunlight is that the black side of the vanes are heated slightly by the sunlight and that causes air to convect upwards which lowers the pressure on that side of the vane causing it to rotate (or something like that). When I last read about this, it was pointed out that these gizmo's actually rotate in the opposite direction than they would if it were light pressure that was moving them. SteveBaker (talk) 20:40, 16 March 2010 (UTC)

Yup. Our articles are pretty explicit about what's actually happening in the Crookes one...exactly how Bkell described it. DMacks (talk) 20:51, 16 March 2010 (UTC)

I like those things you get at the geek store that are black on one side and white on the other and spin when you put them in the light. We should expand the concept to train-sized models. —Preceding unsigned comment added by 99.254.8.208 (talk) 05:22, 18 March 2010 (UTC)

Scientific results on animal telepathy?

Where can I find reliable information about animal telepathy? GerardLP (talk) 11:10, 16 March 2010 (UTC)

I know where to reply unreliable information: Google "animal telepathy". This paper, critical of animal telepathy advocate Rupert Sheldrake, is by academic psychologists who unsurprisingly find no evidence for psychic dogs. The article here on Rupert Sheldrake is also quite detailed. This article and this one from skepdic.com have some useful information and links, including responses from Sheldrake. The Clever Hans phenomenon is also relevant.[11] If you Google and work your way through the results you should find more. --Normansmithy (talk) 12:24, 16 March 2010 (UTC)

Let's be comepletely, 100% clear on this: There is absolutely zero proper scientific evidence for telepathy of any kind - animal, vegetable or mineral. However, dogs (in particular) often seem "telepathic" to humans because they have (non-psychic) senses that are more sensitive than ours. For example, my dog is able to tell from body language alone when I'm about to take him for a walk. This isn't telepathy - this is an animal that (in the wild) cannot rely on speech to know when the pack is about to go off hunting - and has to learn from subtle details of body posture. A pet dog uses those same skills to make seemingly impossible judgements from data that's too subtle for humans to notice. Those who seem to seek psychic explanations for everything are only too happy to interpret this behaviour to "telepathy" - which is a ridiculous assumption in the absence of controlled experiments. SteveBaker (talk) 12:39, 16 March 2010 (UTC)

Or the dog barks at the door before somebody knocks, not because they're psychic, but just because they heard them walking up the sidewalk, and we didn't, because they have better hearing. StuRat (talk) 14:18, 16 March 2010 (UTC)

Check out paramecium. Bus stop (talk) 14:20, 16 March 2010 (UTC)

The paper Bus stop is referring to does not imply telepathy but rather a possible communication system based on production of photons. There are plenty of species with bioluminescence, so how is this relevant to a discussion about telepathy? One might also notice that the article in question was published on April 1, 2009... I'd be rather surprised if PlosONE was playing an April Fool's joke, but it wouldn't be the first time someone made a gag in the scientific literature. --- Medical geneticist (talk) 16:44, 16 March 2010 (UTC)

They also have a "formal correction" to that article, and it is dated 21 July 2009, a date also known for its practical jokes. I find it here. Bus stop (talk) 16:51, 16 March 2010 (UTC)

Interspecies communication may be relevant. ~AH1^(TCU) 17:27, 16 March 2010 (UTC)

Treadmill vs uphill

What gives the most efficient exercise: Running on a treadmill that simulates movement uphill, or running up an actual hill with the exact same steepness? HenriT2 (talk) 11:34, 16 March 2010 (UTC)

I suppose it depends on your definition of "efficient". If both are at the same slope and all else is equal, then it's hard to imagine how there would be a difference. However, if your definition of "efficiency" is something like "calories burned per time expended" then if the treadmill is at home and the equivalent hill is a 10 mile drive from home - then the treadmill is "more efficient" just because you waste less time getting there and back. But then if things are not equal, it might be that the weather outdoors produces different air temperatures and humidity than where the treadmill is - so you'd be burning different amounts of energy because of that. SteveBaker (talk) 12:29, 16 March 2010 (UTC)

Steve seems to have forgotten the fact that in a treadmill you're not actually going up and the person's potential energy won't change. That makes a difference. Dauto (talk) 12:39, 16 March 2010 (UTC)

Your potential energy doesn't increase, but you have to expend energy to prevent it from decreasing. If you just stood there, you'd slide downhill (even with the treadmill off). If (and it's a big if) the treadmill offers minimal frictional resistance to sliding downhill, then walking/running an inclined treadmill should require the same power output as going up the same slope at the same speed. --Trovatore (talk) 20:00, 16 March 2010 (UTC)

Hmm -- now that I think about it, if there weren't any friction, you couldn't avoid sliding down no matter how hard you ran. So I guess the relationship is more complicated. Just the same, increasing the slope will make you work harder, even if it doesn't exactly track the effect of the same slope on a trail. --Trovatore (talk) 20:08, 16 March 2010 (UTC)

I'm not sure that case is actually achievable. I disagree about spending energy to prevent sliding - you just need decent grip on your running shoes for that. It's just like a weightlifter holding weights above his head - he doesn't require any energy to hold them there (under idealised assumptions, anyway - some energy is used to keep the arms rigid, but that's biology, not physics, and biology is far too complicated for me!), energy is only needed to lift them. The energy is used to counter the treadmill moving downwards, the friction between your feet and the treadmill should always be static friction. --Tango (talk) 20:31, 16 March 2010 (UTC)

I hadn't seen this paragraph — no, I'm afraid you've missed the point here. It's not about the friction between your feet and the treadmill; it's about the friction in the rollers.

Think of the treadmill going a constant 3 mi/hr or something, at an incline of 0. Now tilt it up. If you don't increase your power output, you will slide downhill. Not because your feet slip on the rubber — in general, they won't — but because the rollers of the treadmill itself will speed up, under the influence of the gravitational force. --Trovatore (talk) 20:53, 16 March 2010 (UTC)

Wait a minute -- no, I think as Stephan says below, it doesn't depend on whether the rollers speed up; you have to expend extra energy in any case. Have to think about this more carefully. Reminds me of the "airplane on a treadmill" thing that Cecil had to straighten out. --Trovatore (talk) 23:36, 16 March 2010 (UTC)

As StuRat says below, you have to look at the route taken, not just the endpoints. This is because the forces involved are non-conservative. If you watch someone on an inclined treadmill closely, I expect you will see them move up and down as the take a step up, then get carried down, then take another step up, etc.. As far as the vertical movement is concerned, the step up will be the same on a treadmill as in the real world, I think. The being carried down shouldn't have any effect on the energy used by the person. The horizontal movement will be different due to air resistance, as has already been mentioned, but that shouldn't be a significant factor for vertical movement because it is so slow (even a high incline is much less than 45 degrees). --Tango (talk) 20:19, 16 March 2010 (UTC)

Sure, but I'm thinking about the case where you move your legs smoothly, keeping your hips (and therefore your center of mass) at roughly the same height at all times. You still have to expend extra energy with increasing slope, to prevent sliding downhill. --Trovatore (talk) 20:23, 16 March 2010 (UTC) (Of course, hanging onto the handrails is cheating.) --Trovatore (talk) 20:25, 16 March 2010 (UTC)

I'm not sure that's right. If the person climbs up a step, then slides back down (without retrieving any of the energy lost in the climb), then the total energy use could be the same as a real hill. StuRat (talk) 12:57, 16 March 2010 (UTC)

Indeed, that is so (always assuming the usual abstractions). If you put on a pair of blind goggles, you cannot distinguish between running on a treadmill and running up a really smooth really long hill. Movement is relative. --Stephan Schulz (talk) 20:34, 16 March 2010 (UTC)

I also disagree with SteveBaker, for other reasons. According to a detailed article at Peak Performance, running on an inclined treadmill is easier than running on a real hill, due partly to the absence of air resistance which is important when running at speed but negligible on a treadmill, and partly to the fact that people on treadmills use different running styles from the real world; measures of oxygen consumption (which indicates how hard an athlete is working) are lower on a treadmill.[12]

In addition, a real hill may be slippery, uneven, or otherwise provide a harder workout. But when planning an exercise regime you shouldn't ignore the psychological factors: while some people find it easier to run on a treadmill (it's dry, you can watch TV), others find it more rewarding to run outside. --Normansmithy (talk) 12:46, 16 March 2010 (UTC)

Air resistance at a few miles per hour for a body with the cross-sectional area of a human is pretty much negligable anyway. SteveBaker (talk) 13:54, 16 March 2010 (UTC)

I don't think that's true. This page (from google) references an old study (Journal of Physiology, vol 207, pp 823-835, 1970) and says:

"the energy cost of overcoming air resistance during track running at a speed of 21.5k/hour (about six metres per second, or 67 seconds per 400m) is about 8% of the total energy cost. By contrast, the air-resistance cost doubles to 16% of total expenditure when running speed goes up to 10m/sec (100m in 10 seconds)."

So if the OP intends to run fairly quickly, air resistance might be a factor. Zain Ebrahim (talk) 14:19, 16 March 2010 (UTC)

10 m/s (22 mi/hr) will win the 100m dash against any but the most elite competition; there's not a person on the planet who can keep it up for a mile. Even 6 m/s is a 4:30 mile. I don't think this is what we're really talking about. --Trovatore (talk) 21:40, 16 March 2010 (UTC)

Yes, but that was just the data from the first google result I tried. The speeds I mention correspond to air resistance accounting for 10% - 16% of energy output. Even at speeds where it accounts for 2% - 4%, it would still be a relevant factor given the wording of this question. Zain Ebrahim (talk) 07:36, 17 March 2010 (UTC)

I would imagine, more generally as the time you spend exercising increases, running on a treadmill would be more efficient as you'd be maintaining a constant speed in order to keep up with the machine. If you're running in real life, you're likely to fluctuate your speed significantly over distance. Regards, --—Cyclonenim | Chat  13:17, 16 March 2010 (UTC)

Another vote for "it depends what 'efficient' means". Running on real ground involves many small supporting muscles in your legs that get less of a workout on the even and steady treadmill. If your goal is to get strong and useful legs, get on the real road. A similar thing happens in lifting free weights versus using weightlifting machines. --Sean 13:38, 16 March 2010 (UTC)

If by "efficient", you mean calories expended per session, then running outside will be more effective. Although there will be some air resistance, the excellent Bicycling Science by David Gordon Wilson explains that, for bicycles at least, the air flow over an outside cyclist rather than one on an exercise bike has a significant cooling effect. They can therefore maintain a moderate-to-high power output for up to three times as long as the person 'cycling' inside (if I recall correctly) before they overheat. There's also a chapter on aerodynamicity of cyclists and a little bit of data scattered throughout comparing other modes of transport, such as running and horseriding. Brammers (talk) 19:50, 16 March 2010 (UTC)

Of course the heating problem could in principle be overcome by putting a sufficiently powerful fan in front of the machine. That said, I really dislike exercise bikes, precisely because they seem like such a parody of real cycling. Exercise machines do have an advantage in terms of being able to use them on a regular schedule, without having to worry about weather and such, but I'd much rather use an upright cross-trainer that works arms and legs at the same time. --Trovatore (talk) 19:57, 16 March 2010 (UTC)

Me too. I ride a real bicycle every day - exercise bicycles are, by comparison, boring and uncomfortable. I much enjoy a good cross-trainer (especially if I get to watch good TV while on it). --Stephan Schulz (talk) 20:28, 16 March 2010 (UTC)

Psychological tests, job interviews

Which psychological tests are most commonly used in job interviews in Western Europe? How reliable are the test results when not interpreted by professional expertise?

First, please sign your posts by typing four tildes afterwards. This webpage [13] gives a good overview of psychological tests commonly used in the UK, together with a history, the evolution of personality classification, and how they work. I recommend you follow the links at the bottom to see things like leadership style tests, which is a common application of such tests in employment situations. --TammyMoet (talk) 17:39, 16 March 2010 (UTC)

They are about as validated as one of the those place mats in a chinese restaurant where you can see if you are a rat, pig, dragon, etc by year of birth. See Barbara Ehrenreich's disturbing book, Bait and Switch, for the way they are misused in the hiring process. alteripse (talk) 02:03, 17 March 2010 (UTC)

I generally find those place mats in organic save the planet health food restaurants. Bus stop (talk) 02:16, 17 March 2010 (UTC)

Are you claimin' you eat healthier than me? alteripse (talk) 02:37, 17 March 2010 (UTC)

Wow -- I had no idea Chinese placemats were used (much less mis-) in the hiring process. --Trovatore (talk) 19:00, 17 March 2010 (UTC)

It would totally explain how my boss got his job, though. 68.51.78.238 (talk) 04:08, 18 March 2010 (UTC)

Photon

When viewing a photon with for example the earth as a frame of reference, the photon is moving at the speed of light with respect to the earth. However, when the photon is used as a frame of reference, the earth - a massive object - seems to be moving at the speed of light with respect to the photon. A massive object should not be able to move at the speed of light, yet all frames of reference are supposed to be valid ones. Could you please explain how this works? Oliver009 (talk) 12:56, 16 March 2010 (UTC)

One of the central points of relativity is that light cannot be used as a frame of reference. In order to be a frame of reference, an actual object would have to be moving at the speed of light. Since that cannot happen, nothing could act as the frame of reference at the speed of light. Photons don't have a perspective. --Jayron32 13:12, 16 March 2010 (UTC)

Because the Earth is not moving 'at the speed of light' but it is the 'difference' in the speed between the Earth and the photon that equals 2.99 10^8 km per second. In other words it is the 'relative speed'.It would just 'appear' that the Earth is moving at the speed of light. This is the point that Einstein managed to explain mathematically, that whatever the observer's view point. the speed of light 'appears' to be constant -regardless of the speed that the observers going.--Aspro (talk) 13:18, 16 March 2010 (UTC)

Light's not that fast. :) Zain Ebrahim (talk) 13:30, 16 March 2010 (UTC)

Whoops: 2.99 10^8 metres per second. Also, in our every day experience this is not a familiar phenomena, so it just needs a bit of time to read through the theory several times to be able to make sense of it. --Aspro (talk) 13:34, 16 March 2010 (UTC)

Jayron is correct. If you allow an inertial frame of reference B that is moving at the speed of light relative to another inertial frame of reference A, then the Lorentz factor for B becomes infinite. An observer stationary in B attempting to measure the speed of an object O stationary in A would find that the proper time between any two observations of O is zero, but so is the proper length travelled by O between those observations. Therefore the speed of O relative to the observer in B would be 0/0, which is indeterminate. Gandalf61 (talk) 13:41, 16 March 2010 (UTC)

From the perspective of the photon, the mass, space and time dilation effects become literally infinite. Making any kind of conclusion from data that is multiplied by infinity is impossible - so "viewing things from the point of view of a photon" is an exceedingly tricky business. Also, the photon is special in other ways - it's speed appears constant no matter the state of motion of the observer...arguably, that means that you can't imagine things from a situation where the photon is stationary and the universe is moving. The photon also has a zero rest-mass, so does it even exist "from it's own perspective"? I think it's safe to say that you aren't allowed to do your thought experiment! SteveBaker (talk) 13:49, 16 March 2010 (UTC)

Economical preference gene?

Has some scientist ever speculated about an economical preference gene? A gene which would make females prefer males in a good - or at least stable - economical situation? --Quest09 (talk) 13:52, 16 March 2010 (UTC)

I don't think "economic" is quite the right word, but a "good provider" is certainly one of the things females look for. StuRat (talk) 14:06, 16 March 2010 (UTC)

Well, it won't be a single gene, most likely. Behaviour is very complex and governed by the interactions of many genes (any learned behaviours, very importantly). It is certainly true that women tend to look for a mate that will be able to support them and their children. --Tango (talk) 14:14, 16 March 2010 (UTC)

And don't forget epigenetic effects. There's lots of good recent research to show that environment can actually affect DNA expression, which is just as important as DNA code itself, and it can do so several generations out. So, a woman may show a higher preference for economic concerns because her great-grandmother nearly starved to death. Time magazine did a recent article on several studies which show that epigenetic information can be passed down to future generations as well, making the entire nature-nurture soup entirely more complex. --Jayron32 14:20, 16 March 2010 (UTC)

Do have a link to that article? It sounds interesting - a new kind of Lamarckism. --Tango (talk) 14:48, 16 March 2010 (UTC)

Question - Jayron, I don't quite understand your example (or epigenetics for that matter). How would the person's gene expression have been influenced by their great-grandparent being starved to death (their grandparent would have been born before the starvation)? If the great-grandmother survived a period of very low resources (due to e.g. not having someone to provide for her) and then reproduced, does the research you mention state that that experience could influence her female descendents to express their genes in such a way so as to make them more likely to have a preference for economic concerns? Zain Ebrahim (talk) 15:32, 16 March 2010 (UTC)

See [14]. Zain Ebrahim is about right. I was speaking in the hypothetical, I don't know if that specific behavioral expression would be controlled in that specific way, but hypothetically, yes environmental pressures on one generation can result in actual biological change in future generations. Environmental effects on a person before they pass on genetic information is found to express itself several generations out. In the article I link above, a study was done on people whose grandparents lived through a "feast and famine" cycle in the Swedish village of Overkalix. It turns out the grandsons of people who lived through famine times had measurably different lifespans than the grandsons of people who lived through feast times. I'll let you read all of the details, but the research seems to conclusively show that environmental pressures can cause inherited epigenetic traits to be passed on to future generations through means other than the DNA code. So inheritance is also environmentally controlled, and not just 100% based on DNA. You can pass on epigenetic traits to your children and grandchildren, even if those epigenetic traits are environmentally determined. --Jayron32 15:41, 16 March 2010 (UTC)

(after EC)<rant>NO NO NO... Epigenetics is NOT a new kind of Lamarckism. I absolutely hate this analogy, which is ALWAYS brought up in the popular press, as though this "new" science of epigenetics somehow dispels Darwinian evolution and suggests that Lamarck might have been on to something. Jayron, the Time magazine article is very interesting, true, but also highly overblown. Yes, some transgenerational effects have been observed, yes epigenetic mechanisms are possible, but the papers they discuss (mostly the ones about the apparent effect of famine on the health of subsequent generations) have nothing in the way of a scientific demonstration that those effects must have been due to epigenetics. There are other plausible explanations, but since "epigenetics" was one of them the popular press seems to have amped up these papers. Note, I'm not saying epigenetics is NOT involved, just that it isn't proven by those papers. Better studies have been done in mice, but even then we're talking about pretty specific changes at specific loci that increases the species' ability to adapt over the short term to ever-changing nutritional quality -- as though the capacity for transgenerational epigenetic influences has evolved through natural selection. </rant>

That being said, Tango's earlier answer about behavior being too complex to be governed by a single gene is almost certainly correct. The evolution of sexual reproduction is a fascinating topic and one of the side-products of the process is the selection for any number of sex-specific specializations (including provision of "economic" benefits) that allow individuals to evaluate the possible "fitness" of their prospective mates, many of which are likely to be complex, multi-gene processes with environmental/learned influences. --- Medical geneticist (talk) 15:57, 16 March 2010 (UTC)

I didn't mean that epigenetics was claiming to replace Mendelian inheritance, but the idea that you can inherit changes in your ancestors caused by their environment is at the very heart of Lamarckism. Sure, this is Lamarckism playing a minor role in predominantly Mendelian inheritance, but it is still essentially Lamarckism. --Tango (talk) 17:05, 16 March 2010 (UTC)

To respond to MG... I understand that the scope of the study cited in the Time article was rather small, and therefore it would be hard to place theory-smashing emphasis on it. However, it does help to provide an impetus to study in that direction. Even if it is 100% accurate and environmental effects can be passed on to future generations epigentically, such a possibility would not fundementally alter the current understanding of Mendelian genetics or of DNAs role in heredity. It would add to the complexity of inheritance, for sure, but such a revelation, if true, wouldn't mean an end to current genetic theory, only a modification of it. And isn't that the idea behind scientific study, to constantly refine and improve our models and theories? --Jayron32 04:29, 17 March 2010 (UTC)

My problem with the analogy is the "Darwinism versus Lamarckism" spin that gets put on this phenomenon in the popular press. The Time Magazine article is a great example. I read it a few months ago so I can't remember the exact phrasing, but they kept talking as though epigenetics was a way to "escape" from the "tyranny" of Darwin. Don't get me wrong -- I'm a huge fan of epigenetics -- but sometimes the importance of epigenetics gets a bit overblown. I understand that Lamarck's ideas have been caricaturized (i.e. the giraffe stretching it's neck in order to give it's offspring longer necks), and of course neither Darwnin nor Lamarck would have had any clue about the molecular mechanisms at play. I totally agree that epigenetics is just another layer on top of the A/C/T/G's that adds to the complexity of the weave. However, epigenetic effects still adhere to mechanisms of natural selection: the genes that encode the proteins that perform these functions, and the DNA letters that are acted upon, can both be selected for. If transgenerational epigenetic effects were maladaptive, they would be selected against in the same way as any other trait. The Lamarck analogy misses the point that the capacity of organisms to be affected by epigenetic transgenerational effects has been selected for because it is adaptive under certain conditions. --- Medical geneticist (talk) 17:59, 16 March 2010 (UTC)

Noise in MRI scan

3D MRI scan

What causes the apparent noise around the head in this image (found on the Neroimaging page)?
Surely this would be simple to remove programatically? Is it normally removed? If so why not in this example? Capuchin (talk) 14:12, 16 March 2010 (UTC)

Googling around MRI noise sources, there appear to be a number of possible culprits. However in this case the positioning of the noise makes me wonder if it isn't some kind of headphones on the patient, which are apparently sometimes used to either cut down on the loudness of the machine, or to pipe in other sound. I'm not sure if the plastic of the headphones itself would generate the noise, but it might be reflecting heat in a strange way, which apparently can create noise (as I gather from Googling). One might also imagine it some kind of brace (I had an MRI a long time ago, and they had my head in all sorts of padding to keep it straight) that might also be reflecting heat in some funny way. This is just speculation on my part, definitely not authoritative! --Mr.98 (talk) 14:20, 16 March 2010 (UTC)

From the square angles, I'd say it's a brace to keep the patient from moving during the scan. StuRat (talk) 14:25, 16 March 2010 (UTC)

Headphones/braces do not contain water, so why would they show up on an MRI? MRI simply aligns hydrogen atoms in water. Regards, --—Cyclonenim | Chat  15:42, 16 March 2010 (UTC)

If the brace is cold and the person's breath is warmer in comparison, it could be some condensation, particularly if the area isn't well ventilated and if the humidity is high. StuRat (talk) 14:33, 17 March 2010 (UTC)

They have barely shown up, so there doesn't need to be much water involved. Perhaps it's the lack of air (which does contain water) that is showing up, rather than the plastic. --Tango (talk) 17:07, 16 March 2010 (UTC)

MRI doesn't literally see water, it sees RF/magnetic effects of it. So all you need is something that perturbs the magnetic field or is susceptible a little differently and you can get a ghost. Our MRI article has several comments about artifacts at solid/liquid boundaries and other field-inhomogeneities. DMacks (talk) 17:37, 16 March 2010 (UTC)

I'm not a radiologist, but it looks like a data glitch to me and not a real physical object.

Don't MRI machines scan one line at a time? If so, that perfectly square interference could easily be explained by some sort of background interference halfway through the scan. (The square shape probably indicates the outer limits of the scan. So really you're looking at noise contained by two planes.) APL (talk) 18:01, 16 March 2010 (UTC)

It could be a halo but those typically have metal screws in them, I don't think a patient with one would be taking an MRI. Livewireo (talk) 18:09, 16 March 2010 (UTC)

I agree with APL. Not only do the vertical lines appear to penetrate through the head, but the pattern continues above and below where the scan cuts off. Unless they were scanning an actual slice of head held in a rack, I don't think that stuff is a real object. Rckrone (talk) 19:43, 16 March 2010 (UTC)

Avocado pit use and safety

Are avocado pits safe for heating? I am making heating packs for self-care use at home and wonder if they are safe to use? If so, do they need to be prepared in any special manner first, i.e. dried,cooked,etc.? —Preceding unsigned comment added by Mehndihum (talk • contribs) 16:24, 16 March 2010 (UTC)

Why use an avocado pit for heating packs? Wouldn't other similar sized and hard objects, which are not perishible, be useful, such as maybe old golfballs or something? I'm not sure there is anything wrong with the avocado pit per se (but don't take my word on THAT), however if there is any doubt, couldn't some alternative object which is about the same size, shape, and hardness work better and leave less doubt of creating problems? Perhaps with more details as to what the old pits would be used for may be helpful in answering your question. --Jayron32 05:16, 17 March 2010 (UTC)

Isn't barley the seed of choice for heat packs? --Polysylabic Pseudonym (talk) 07:29, 17 March 2010 (UTC)

Heating hard-shelled objects with moisture at the center is generally an iffy proposition--think whole eggs in a microwave, or tin cans in the campfire, or--for an example neither fundamentally messy or dangerous, popcorn. The safety issue would depend largely on variables within the pit itself and the temperature to which you're heating it--popping an un-punctured avocado pit into a microwave and hitting START seems like it could go very wrong, depending on the moisture content and any variations in the structure of the pit's walls. 68.51.78.238 (talk) 04:06, 18 March 2010 (UTC)

Programmable food

Since taste, like smell, is perceived based largely on the shape of surface molecules on the food, and since smell is a big part of the tasting experience (compare eating with a stuffed nose to eating without a stuffed nose), have any researchers published papers (preferably in open journals) on the possibility of developing edible molecules with customizable shapes for the purpose of having customizable taste? I think it might be interesting if you could first buy a device like a microwave, and from then on, buy blocks of product which you could put in the device and activate programs which could be downloaded from (definitely trusted) sources or alternatively programmed yourself if you become a programmer/chef hybrid? 20.137.18.50 (talk) 17:34, 16 March 2010 (UTC)

Well, there is a lot of work on manufacturing chemicals that makes things taste a certain way. See Flavorist. Whether some kind of home-made device would ever let you do this, it's a long way off. You're essentially describing a Molecular assembler that is just tailored to food molecules. I think it would be pretty easy to poison yourself if you didn't know quite a bit of chemistry (just as it is with "traditional" means of chemical experimentation). --Mr.98 (talk) 19:02, 16 March 2010 (UTC)

"Te voy a llevar a un pinche vaile!"

This question has been moved to the Language Desk. Nimur (talk) 18:24, 16 March 2010 (UTC)

Flow through a pipe

Engineering. with a given pressure and the area of a pipe and without the velocity is it possible to find the flow rate by calcultion? If there is a calculation available, pls. let me know. —Preceding unsigned comment added by 212.100.212.214 (talk) 17:39, 16 March 2010 (UTC)

I think you need to know something about either the fluid itself (like viscosity) or the pressure drop for the pipe length. DMacks (talk) 18:00, 16 March 2010 (UTC)

The simplest approximation is the fluid continuity equation. You can see which parameters are needed to relate flux (the generalization of linear flow rate to 3 dimensions). In this case, the net velocity flux is zero - or, in laymans terms, "the flow rate is exactly equal everywhere in the pipe, and is determined by how much fluid as you squish in on the supply-end." (That is, your problem is totally determined by its boundary conditions). Note that increasing pressure does not necessarily equate to increasing the mass flow rate - but in practice, these effects are commonly related (because you probably use a pump as your fluid supply, which works by pressurizing the fluid). It should be possible to approximate your flow in a pipe scenario under some more complex circumstances. More complete treatments, like Navier-Stokes equations, relate pressure, velocity, compressibility/density change, fluid shear, etc.; and while more complicated, they are applicable in a wider array of situations. Nimur (talk) 18:29, 16 March 2010 (UTC)

Are you talking about a gas or a liquid? I know that you can measure the speed of gas flow through a pipe if you can get a differential pressure across an orifice plate if the gas properties are known. Googlemeister (talk) 18:33, 16 March 2010 (UTC)

That would be the venturi effect. Nimur (talk) 18:34, 16 March 2010 (UTC)

The properties of the pipe would also be important. The cross section should ideally be circular, and the pipe should be straight for best flow, yielding a cylinder. Also, some surfaces will be smoother and thus have less drag. StuRat (talk) 14:13, 17 March 2010 (UTC)

Electrode potential of ethanol

What is the standard electrode potential of the oxidation of ethanol to ethanoic acid, hydrogen ions and electrons, as found in modern day breathalysers?

I have tried googling this question but could not find a suitable answer, I am just looking for a value.

Thanks 86.164.85.183 (talk) 18:20, 16 March 2010 (UTC)

Most electrode potentials are listed as reductions and not oxidations, so you'd want to phrase your search for reduction potentials of acetic acid or ethanoic acid or CH3COOH or HC2H3O2 (all synonyms) rather than oxidation potentials for ethanol. The value will have the same sign and opposite magnitude. --Jayron32 20:36, 16 March 2010 (UTC)

Thanks 86.164.85.183 (talk) 22:37, 16 March 2010 (UTC)

Bee Flies

Hello, I live in Langley, BC, and I saw these two (right) Bee flies mating on the ground. Can anyone tell me what species they are? --The High Fin Sperm Whale 18:59, 16 March 2010 (UTC)

I just looked at a bunch of bee flies here and here, and most of them looked quite a bit more bee-like than your critters. How do you know they are in fact bee flies? There are ~4500 species and I'm ignorant of all of them, so they may well be, I'm just wondering how you reached that conclusion. --Sean 19:54, 16 March 2010 (UTC)

These were quite a bit larger than most flies, about ¾ inch long. But maybe they weren't bee flies. Anyone know what they are? --The High Fin Sperm Whale 21:35, 16 March 2010 (UTC)

Horse fly first came to mind. Beyond that, I don't know. --Kvasir (talk) 22:54, 16 March 2010 (UTC)

I'm pretty sure that these are Tachinid flies, not bee flies.174.97.22.101 (talk) 05:22, 17 March 2010 (UTC)

Looking under Family Tachinidae and even its Superfamily Oestroidea definitely looks a lot closer to the OP's picture. --Sean 16:36, 17 March 2010 (UTC)

I've made an ID request over here. --Sean 16:50, 17 March 2010 (UTC)

most effective footrace training?

If I was to start training for a 3 mile footrace and wanted to complete it at a pace of 6 min a mile which would be a more effective means of training

A. Run as far as possible at the 6 min/mile pace and gradually increase the distance

B. jog 3 miles at a slower pace and gradually speed up to the 6 min/mile pace?

Googlemeister (talk) 19:27, 16 March 2010 (UTC)

Definitely B if you're starting from no running at all. Option A is a recipe for self-injury and then you'll have a huge time-out in your training. --Sean 19:39, 16 March 2010 (UTC)

You may want to look into LSD training and Interval training and Fartlek for information on different training styles for running. You may also want to consider contacting a coach or a physical trainer in your area. A local running club may be able to provide some training guidelines as well. --Jayron32 20:11, 16 March 2010 (UTC)

Flour from Grasses

Why is wheat and spelt flour so high in carbs when they just come from grass? Are there any edible grassess or seeds (not counting the nut flours) that are low in carbs and taste good that can be made into flour? Also, is it the seed of the wheat plant that is ground up and made into flour? —Preceding unsigned comment added by 71.137.244.162 (talk) 19:58, 16 March 2010 (UTC)

It is the seed of the wheat plant that is made into flour. I don't know low carb flour. Googlemeister (talk) 20:01, 16 March 2010 (UTC)

Information about flour can be found, unsurprisingly, in the article titled Flour and in links from that article. Start there, read that article, follow some blue links and read THOSE articles. They answer all of your questions and more. --Jayron32 20:07, 16 March 2010 (UTC)

(ec) Yes, it is the seeds of wheat that we use for food (the stalks are used as straw). I think any seed will be high in carbs, it's the easiest way to store energy for the new plant to grow with. You can make flour out of all kinds of things (see Flour#Other flours for a list), but I think they will all have a fairly high proportion of carbohydrates. --Tango (talk) 20:08, 16 March 2010 (UTC)

Would it be possible to make flour from just about any seed? For example, I just saw that there is a grapeseed flour that you can use to cook with what about the seeds from pomegranites or avocadoes or goji, could you make a flour from those? —Preceding unsigned comment added by 71.137.244.162 (talk) 21:53, 16 March 2010 (UTC)

Probably. It wouldn't necessarily taste very nice, though, and it may not behave well when cooking. --Tango (talk) 23:20, 16 March 2010 (UTC)

Soy flour is about 40-50% protein [15] [16] [17] . However, I never tried to cook with it, so caveat emptor. --Dr Dima (talk) 23:36, 16 March 2010 (UTC)

Caveant cucinator et cenator. --Trovatore (talk) 23:46, 16 March 2010 (UTC)

Chemistry

What do you get if iron(III) oxide reacts with hydrogen? --70.250.214.164 (talk) 20:38, 16 March 2010 (UTC)

Iron is higher up on the reactivity series than hydrogen, so there would be no reaction. --The High Fin Sperm Whale 21:33, 16 March 2010 (UTC)

I would be really surprised if you couldn't reduce it to elemental iron by passing hydrogen over it. You might have to heat it, and maybe you'd need a continuous flow, so that the moisture gets carried away and can't re-react with the iron. --Trovatore (talk) 23:39, 16 March 2010 (UTC)

Iron(III) is a catalyst used for making lithium and sodium amide: Li+NH₃→LiNH₂+H₂ in the presence of (NO₃)₃ below 0 °C but doesn't occur at all without the iron even at higher temps. I assume the iron is an electron shuttle, which would mean something like Fe(II)→Fe(III) strongly overcomes H₂→H⁺ under these conditions. And the Haber process tells us that at high temp and pressure, iron(III) transfers electrons from H₂ onto nitrogen gas, so again "just reducing to iron" is pretty difficult vs reducing other things. DMacks (talk) 00:05, 17 March 2010 (UTC)

Hmm -- well, maybe I get to be surprised, then. Still, surely the reaction coefficient isn't zero? If you remove the reaction products, it ought to go to completion? --Trovatore (talk) 00:48, 17 March 2010 (UTC)

strontium iodide

Does strontium iodide decompose by itself (without oxygen or other chemicals)? --70.250.214.164 (talk) 21:03, 16 March 2010 (UTC)

I don't think so. --The High Fin Sperm Whale 21:31, 16 March 2010 (UTC)

The compound Strontium iodide is stable. Some iodine compounds react when UV radiation is present. A yellow tint is what I would expect. --Stone (talk) 22:23, 16 March 2010 (UTC)

According to our article, on Strontium iodide, the yellow tint comes from being exposed to air. 70.250.214.164 asked if it would decay without oxygen. --The High Fin Sperm Whale 22:44, 16 March 2010 (UTC)

I am sure that UV also would do the trick without oxygen. --Stone (talk) 22:50, 16 March 2010 (UTC)

March 17

Chocolate/Theobromine poisoning

I know that chocolate (and a few other things containing "Theobromine") is poisonous to dogs and cats (also to horses, parrots and voles). It's not poisonous to humans except in pretty large quantities. Theobromine poisoning doesn't tell us much more than that. How far from humans can a mammal be (from an evolutionary/genetic perspective) and still be able to eat the stuff? Are humans unique? How about chimps? What is the evolutionary benefit to us? It's hard to imagine an evolutionary pressure to survive eating chocolate, tea, cola and Açaí Palm berries. Is there some other metabolism that requires theobromine tolerance? SteveBaker (talk) 01:11, 17 March 2010 (UTC)

So the article claims

A typical 20 kg (44 lb) dog will normally experience intestinal distress after eating less than 240 g (8.5 oz) of dark chocolate

Now, if you scale that up to my weight, I'm pretty sure that would cause me intestinal distress, too. Maybe the risk to dogs is overstated? Or is it more that dogs, who evolutionarily were opportunistic feeders, are more likely to actually eat half a pound of chocolate? --Trovatore (talk) 01:14, 17 March 2010 (UTC)

But look at the "oral toxicity" chart at the top-right. Humans can tolerate twice as much theobromine per kg of body weight as a dog - and we can metabolize it much faster than they can. In dogs, the dosage is cumulative over days - in humans it's barely cumulative at all. I think there is some significant biochemical difference here. SteveBaker (talk) 01:44, 17 March 2010 (UTC)

Chemically, theobromine is almost identical to caffeine, and AFAIK has a similar effect on the body. The difference between the two is a single methyl group off one of the nitrogens (caffeine has it, theobromine doesn't). Given my rather limited understanding of alkaloid metabolism, I'm not sure there's fundementally much difference as to how your body would process these chemicals; they form a "class" much as morphine-derivative opiates do, like codeine, morphine, hydrocodone, vicodin, etc. etc. do. In fact, looking at the them, it looks like the difference between codeine and morphine is almost exactly the same as the difference between theobromine and caffeine (1 methyl group) and our article on codeine mentions in the pharmacology section that the body processes codeine into morphine, however only at about a 5-10% efficiency rate, which is why codeine is slower acting and less addictive than morphine. I wonder if a similar relationship exists between caffeine and theobromine; in that case the methylated version (caffeine) would be slower acting by analogy, which would mean that theobromine would be somewhat more dangerous gram-for-gram. However, this is all a giant WAG, as the human body can behave rather unpredictably in these areas, so one would actually need to look for throbromine pharmacology and pharmacokinetics studies. --Jayron32 05:29, 17 March 2010 (UTC)

According to caffeine, 12% of that compound is metabolized into theobromine, the rest goes down different pathways. They all have some similar effects but the pathways do not appear to reconverge at a later pharmacologically important point prior to excretion. DMacks (talk) 08:44, 17 March 2010 (UTC)

So that does match my intuition regarding the similarity in relationship between caffeine/theobromine and codeine/morphine, at least on the methylated version metabolizing into the non-methylated one, and at roughly the same rate. However, as DMacks notes, it does appear that beyond that point, metabolicly they are treated differently. That does not necessarily mean that neurologically they are, however, or toxicogically. --Jayron32 14:37, 17 March 2010 (UTC)

Let me offer a hypothesis for the evolutionary difference. People, being omnivores, eat a wide variety of foods, some of which include theobromine. And, at times, they may exclusively eat such foods. Therefore, a tolerance for theobromine would be evolutionarily selected for. Most other animals have a more restricted diet. Thus, unless this restricted diet includes food items heavy in theobromine, there would be little evolutionary pressure for them to develop this tolerance. It would be interesting to check if other omnivores, such as bears, also have a tolerance. StuRat (talk) 13:58, 17 March 2010 (UTC)

If you're planning on doing some OR with a Hershey bar and a grizzly, please let us know how you make out. Matt Deres (talk) 16:57, 17 March 2010 (UTC)

If dogs were actually carnivores, that would make sense. In my experience, they are only slightly more selective than goats when it comes to food. Might be interesting to see if there was a difference in the tolerance between dogs and wolves; have 100,000 years of living near humans and stealing (or being fed) human food changed dogs' digestion? —ShadowRanger ^(talk|stalk) 18:00, 17 March 2010 (UTC)

Galaxies as iron filings

Some galaxies

If all the Galaxies in the Universe were viewed as little iron filing with the axis perpendicular to the Galactic plan where the clockwise side was the North pole and the Universe viewed as a giant magnet or coil how would the little Galaxy iron filings line up and in what direction would they point? 71.100.11.118 (talk) 01:27, 17 March 2010 (UTC)

You don't have to guess - look at the famous Hubble Deep Field photograph. The axes of the other galaxies are not parallel to ours - they are oriented in all possible directions...seemingly at random. File:2MASS LSS chart-NEW Nasa.jpg is a picture that shows the large-scale structure of the universe around us - and it seems that galaxies are not evenly distributed - they are mostly grouped into vast strands. However, don't read anything into this in terms of our galaxy somehow influencing the other magnetically or anything - our galaxy is just one of a zillion others. SteveBaker (talk) 01:38, 17 March 2010 (UTC)

The galaxies seem to be orientated randomly. You might find Large-scale structure of the cosmos interesting. Astronaut (talk) 01:57, 17 March 2010 (UTC)

It is unlikely that galaxy-sized objects have any significant net electromagnetic properties. To my knowledge, no evidence of a galaxy-sized magnetosphere has ever been observed - it is not even clear what evidence could possibly exist to establish or discredit the idea of a galaxy-scale magnetic field alignment. Galactic magnetic fields seems to be a nice overview of the debate; and here is an IOP article about radio measurements of magnetism in the outer galaxy. Nimur (talk) 02:03, 17 March 2010 (UTC)

Here is an overview of a Very Large Array experiment to place an upper-bound on the magnitude of an interstellar / inter-galactic magnetic field. Its result - evidence for a very weak field (presented at a conference, not a peer-reviewed journal). Nimur (talk) 02:08, 17 March 2010 (UTC)

I am referring to magnetism only in the context of it being polar force where alignment along the lines of force in the magnetic field is obvious. Now drop the notion of magnetism and consider the force of gravity instead. 71.100.11.118 (talk) 03:18, 17 March 2010 (UTC)

Some work in the 1970s seems to indicate that inside a galaxy, certain structures align parallel to the galactic plane - see The alignment of interstellar dust clouds and the differential z-field of the galaxy, for example. However, this is not the entire galaxy aligning with respect to something in the universe - the alignment of individual galaxies appears to be random, and their position appears to be in the form of "strands" or superclusters. Nimur (talk) 03:46, 17 March 2010 (UTC)

I'm referring to the central perpendicular galactic axis alignment and not to the alignment of matter within the Galaxy with the central perpendicular galactic axis. Although many things look random in nature (and in the presence of dark matter and energy throughout the Universe) you can not tell for sure just by looking. Instead you have to measure the angles of all the central perpendicular axis and determine what points in the Universe their imaginary projections intersect in order to know for sure. 71.100.11.118 (talk) 06:13, 17 March 2010 (UTC)

Valid point. I was not able to find any reputable source indicating that any alignment exists, even statistically, for all the galactic axes we have observed. If you think such an alignment does exist, you should find some evidence to support that belief; very likely, somebody else has studied this problem, and if there were a conclusion to be drawn, it's probably published in a reputable scientific journal somewhere. Nimur (talk) 06:24, 17 March 2010 (UTC)

It's remotely possible that some kind of universal "directional influence" exists for galaxies - but if it's there, it has to be extremely subtle because just a quick glance at the Hubble deep field photo is enough to tell you that the axes of the galaxies are all over the place. In just that tiny patch of the photo that I posted (above), you can see galaxies that are everywhere from edge-on to full-on - and that the edge-on ones come in all kinds of rotations compared to the 'vertical' axis of the photo. So if there is some kind of aligning effect, it must be something exceedingly subtle and statistical in nature or we'd see it in the Hubble photo. I think another problem for this idea is that galaxies are not rigid bodies - they are vast collections of individual stars. If some 'aligning force' existed, it wouldn't turn the axes of rotation towards some universal direction without also messing with the shape of the galaxy under its rotation. Hence, there wouldn't be any circular galaxies unless they happened to start off spinning with the right axis. We'd see that galaxies that don't lie in the "universal direction" would be warped...and again, there is no sign of that happening. So given that (a) we have no idea what kind of a force could do this and (b) there is no sign of this alignment happening in practice - then Occam's razor says that we need not concern ourselves overly much with this issue. SteveBaker (talk) 12:33, 17 March 2010 (UTC)

Don't be quite so quick to step from the deep field photos to "no". In any given direction, the deep field photograph extends through quite a lot of space (à la optical double), so it's possible that we see galaxies with all alignments because we're looking through a variety of non-aligned "field lines" in every direction. However, you're quite right that there's currently no reason to read that much complexity into the image. --Tardis (talk) 13:15, 17 March 2010 (UTC)

Well, if we have to get into details - there have actually been at least four similar studies done by the Hubble (Extended Groth Strip, Hubble Deep Field South, Hubble Ultra Deep Field and Hubble Deep Field) - each looking in a different direction. The express reason for doing at least two of those studies was specifically in order to verify the "Cosmological principle" - that the universe is homogeneous on large scales. The redshifts of the galaxies imaged are known - so their distances are known. If there were some alignment of galactic axes (which would be a violation of the cosmological principle), it would certainly have been noticed - even if the nature of that alignment were a function of distance or direction. In fact, they did notice a change in the shapes of galaxies that are very far away which can be traced to the fact that such distant galaxies were still quite young when the light that Hubble captured left them. SteveBaker (talk) 02:39, 18 March 2010 (UTC)

Chart

[18]

What is the PM and AM?174.3.107.176 (talk) 01:42, 17 March 2010 (UTC)

I presume these are the morning (AM) and evening (PM) - "opening" and "closing" prices on the commodities market...but I suppose there are other possibilities. SteveBaker (talk) 01:54, 17 March 2010 (UTC)

(ec) That chart represents spot prices for platinum on the London Platinum and Palladium Market. The Market's website has a brief history, which explains that statistics are kept for morning (AM) and evening (PM) spot prices (for historical reasons, a twice-daily record is kept). "In 1973 the London Platinum Quotation was introduced. It was the forerunner of the fixings; a twice-daily indication of the market price for spot platinum, reported by some of the principal companies dealing in the metal."[19] If you're interested in the origin of "AM" and "PM" as used in conventional time-keeping, see 12-hour clock#Abbreviations - ante meridiem and post meridiem. Nimur (talk) 01:56, 17 March 2010 (UTC)

That's "weird". I always thought prices were determined by the less-then-second.174.3.107.176 (talk) 03:20, 17 March 2010 (UTC)

Even in a modern electronic trading exchange, prices are averaged over a time-window. This New York Stock Exchange article from 2009 suggests that their computers run on a 62 millisecond latency (and soon to "improve" to single-digit millisecond latency); the effects of other system latencies mean that the actual price may be stale by the time an electronic transaction executed... but since the exchange is committed, it must go through with the new 62-ms window price. Back in the "old days", prices were averaged out over even longer periods, but with essentially the same hazard - if the price changes after a commit but before an execute, the trade must go through with the new price. You can see why less frenetic markets (like pork futures or the palladium market) might aim for once- or twice-daily price updates. Nimur (talk) 03:39, 17 March 2010 (UTC)

The bid and offer prices quoted by individual market makers during the trading day do change on a second-by-second basis, as each market maker adjusts their prices depending on the supply and demand that they see in the market and their current positions (long or short). The twice-daily fixings are an additional pricing mechanism in which an auction process is used to determine a benchmark price. The benchmark price is used as a reference price for settling precious metals swaps, options and other OTC derivative trades. This is explained in the Guide to the London Precious Metals Markets - see the section headed "Dealing and Products".

Returning to the original question, the chart shows 17 pairs of data points and the timeline is 17 years, so each data point could represent the average of the AM or PM fixings over a 12-month period - but without more information on the origins of the chart, it is difficult to be certain. Gandalf61 (talk) 10:09, 17 March 2010 (UTC)

The image page for the chart claims that it's the contributor's own work (User:Bloublou) - so you could just contact the person who created it and ask. Bloublou's talk page seems under-used but there is an "Email this user" button in the menu to the left. SteveBaker (talk) 12:19, 17 March 2010 (UTC)

Question on Sapphire and Blue Emrald.

This is for the geology/ earth sciences experts out there. To cut a long story short I want to wear a blue sapphire set in gold ( for sentimental reasons) as a ring. Im not here to debate my faith or the pros and cons of wearing precious stones in rings. When I approached a trusted jeweller, and asked for the best Blue Sapphire he offered me a 9 carat blue Emrald. Im not an expert in stones but not daft either, I was told specifically to buy a blue sapphire, preferably a natural blue- deep blue - which is not heat treated. I listed out my requirements and the jeweller says Blue Emralds and blue sapphires are one and the same - just the name is different. He says the stones are from Sri Lanka though I was advised that the best Blue Sapphires came from Kashmir, India. Is a blue Sapphire same as a Blue Emrald? Structure wise and characteristics wise... Any gemmology experts out there who can help me? —Preceding unsigned comment added by 213.130.123.12 (talk) 04:37, 17 March 2010 (UTC)

Your jeweler is either a) Bullshitting you on purpose or b) completely incompetant. Sapphires are a variety of corundum which also includes gemstones such as ruby. Emeralds are a variety of beryl, which includes gemstones such as aquamarine. They are completely different chemically. So my advice is to find someone else ASAP, since this guy is either dishonest or incompetant. --Jayron32 04:45, 17 March 2010 (UTC)

I have to agree, no one should ever tell you that an emerald and a sapphire are the same thing, even with my lay knowledge this jeweler is either trying to rip you off or is completely incompetent. I would find it hard to believe that even the most ignorant of people in this trade would not know the difference in the two. Beach drifter (talk) 05:10, 17 March 2010 (UTC)

I won't be as hard on the jewler. He may be an excellent artist but clearly doesn't know enough about emeralds and saphires to be trusted on that score. So feel free to trust him to set a stone in a ring, but trust yourself and these strangers on the interwebs to identify stones. See also saphire and emerald... reading my own links and those above I note no mention of blue emerald in either emerald or beryl, ultramarine is pale blue, and maxixe is a deep blue beryl (which fades with exposure to sunlight and can be restored with irradiation with neutron, gamma or x-rays). Other pale forms of beryl can be made into maxixe through irradiation.

To further confuse things, pale blue corundum (saphire) is also called "oriental aquamarine" which could have confused your jewler -- a pale saphire is called aquamarine - a blue emerald.

So I don't think you'll have much trouble finding blue emerald (but called maxixe or aquamarine) but you'll have no chance of knowing whether it was dug from the ground blue, white or gold in colour, and note that x-raying isn't heat treating. --Polysylabic Pseudonym (talk) 07:55, 17 March 2010 (UTC)

Thanks for the answers. I for sure knew Sapphire isnt an Emrald but I thought technically a blue Sapphire was indeed a blue emrald. Thanks for the scinetific explanations, yes I have since done extensive online searches and I am going in for a 5 carat ( non heat treated ) blue sapphire. Thanks again. —Preceding unsigned comment added by 213.130.123.30 (talk) 08:54, 17 March 2010 (UTC)

My telescope

If my new telescope (the one with nearly a billion cameras all pointing at the same infinite point in space) finds a distant Galaxy that is 20 billion light years away then isn't the Universe over 15 billion years old or is there something weird going on here? 71.100.11.118 (talk) 06:00, 17 March 2010 (UTC)

Yes, something weird is going on here. See Distance measures (cosmology). Basically, there are different ways of measuring distance on these large scales, and it is indeed possible to come up with a value in light years larger than the age of the universe. I welcome someone else to explain some of these different distance measures to me, because I sure don't understand them. Buddy431 (talk) 06:09, 17 March 2010 (UTC)

An important question arises: how did you determine that the galaxy you (hypothetically) observed was 20 billion light years away? Did you use the redshift and Hubble's law? It's worth knowing some of the assumptions you are making. Nimur (talk) 06:29, 17 March 2010 (UTC)

See Inflation for how the universe got to be bigger than its age in light years; and

for the rest of the story see Observable universe which tells you in its lead section:

The age of the Universe is about 13.7 billion years, but due to the expansion of space we are now observing objects that are now considerably farther away than a static 13.7 billion light-years distance. The edge of the observable universe is now located about 46.5 billion light-years away.

--Polysylabic Pseudonym (talk) 08:12, 17 March 2010 (UTC)

The OP's proposal for an exhorbitantly expensive and complex array of CCD cameras that would somehow by means of vaguely described software match the performance of conventional reflecting or refracting telescopes was discussed last November. I conclude that the construction is not worth pursuing and it is never going to discover a new galaxy because it will not be built so the OP will never own one. Aside from the obsession about a "billion cameras", the OP's question is logical Cuddlyable3 (talk) 12:53, 17 March 2010 (UTC)

Remember that seeing a galaxy 13.7 billion light-years away means you're looking 13.7 billion years back in time. So the galaxy may not be there any longer. ~AH1^(TCU) 16:26, 17 March 2010 (UTC)

Is that equivalent to saying that the galaxy is still where it was but you are no longer where you were? Cuddlyable3 (talk) 17:22, 17 March 2010 (UTC)

Decomposition

Assuming an average of all conditions, how long would it take for an unembalmed human corpse to completely decompose (bones and all) after being buried 6 feet underground with shrouds but no casket? My goal is to have a time frame for which, theoretically speaking, one could plow over and/or dig for construction purposes without having any indication that the land had been used as a graveyard. DRosenbach ^{(Talk | Contribs)} 13:39, 17 March 2010 (UTC)

I'd imagine there are too many factors to work out a reliable time frame. Temperature, oxygen availability, scavengers, humidity etc. are all factors in the speed of decomposition, so without a specific location I doubt it'd be possible to work out as a general rule of thumb. Sorry to be so unhelpful. Regards, --—Cyclonenim | Chat  14:27, 17 March 2010 (UTC)

Agreed, but it's likely to be on the order of thousands of years for bones and teeth to completely decompose. Also note that human bodies are likely to be buried with items which don't decompose, such as gold jewelry or stone tools. StuRat (talk) 14:30, 17 March 2010 (UTC)

If the conditions are favorable the bones might never decompose and start fossilizing instead. Under extremely favorable conditions even the soft parts might fossilize. Dauto (talk) 15:23, 17 March 2010 (UTC)

It's really so variable? That's surprising! OK...how about Jerusalem and how about the NY Metro area. DRosenbach ^{(Talk | Contribs)} 15:29, 17 March 2010 (UTC)

The specific information you are requesting may not be in our article on Body farm, but it may be a good place to start. 10draftsdeep (talk) 15:49, 17 March 2010 (UTC)

Wait a while longer before you plough over this gentleman. Cuddlyable3 (talk) 17:19, 17 March 2010 (UTC)

Digoxin in health

From the digoxin article, cardiac glycosides primarily have negative chronotropic/positive ionotropic effects on the heart. While such effects are deemed therapeutic for patients suffering from forms of heart failure, etc., how are such effects so harmful as to be toxic to humans who do not exhibit heart failure. The focus of my question is on consumption of milkweed (or foxglove for that matter) -- is the toxicity of the plant related to the high concentrations of the glycoside? Because if it's not, I don't see how the cardiac effects I indicated above would be all that harmful. DRosenbach ^{(Talk | Contribs)} 13:45, 17 March 2010 (UTC)

Why would cardiac glycosides have a negative chronotropic effect? Chronotropics affect the heart rate, and cardiac glycosides cause tachycardia in high doses. I don't know how this relates specifically to your question so I'll let someone answer more directly, but cardiac glycosides (such as those present in foxglove) do have the ability to cause tachycardia and eventually fibrillation. Regards, --—Cyclonenim | Chat  14:23, 17 March 2010 (UTC)

That's what it says in the Digoxin article. DRosenbach ^{(Talk | Contribs)} 15:27, 17 March 2010 (UTC)

Animal clitorises

Do most mammals have them, and if so, are they external, or is the external clitoris exclusive to humans (or primates maybe)? I hear tell that pigs have them internal to the vagina. External raises certain evolutionary questions, as you can imagine. How come masturbation isn't selected against since it would seem to distract from reproduction? Is it the vague benefit of comfort, or some social function? 86.21.204.137 (talk) 15:08, 17 March 2010 (UTC)

Clitoris certainly implies, but does not actually state, that most mammals have them. Lfh (talk) 16:03, 17 March 2010 (UTC)

It is rather difficult to select against. If sexual intercourse is pleasurable, then anything that simulates sexual intercourse will be pleasurable. It does seem to be selected against to some extent, though - actual sex is generally more pleasurable than masturbation (this isn't just anecdotal, there have been studies that have shown the relevant hormones stay in the body longer, or something, after sex than after masturbating). --Tango (talk) 16:25, 17 March 2010 (UTC)

. Please cite references. I believe Kinsey (and Masters and Johnson as well) contradict you on the claim that masturbation is less pleasurable than intercourse, at least for the perceived strength of orgasm. Comet Tuttle (talk) 17:28, 17 March 2010 (UTC)

Furthermore, since a clitoris is basically a homolog to the penis glans, it would seem to be somewhat evolutionarily impossible to see a species where the male had a penis, but the female has absolutely no clitoris. Males of all mammals have nipples, and the same number and distribution thereof as females, even if they don't give milk, sexual dimorphism in mammals can give rise to variations between the sexes, but you don't have any situations where entire organs in one sex are completely missing from the other. You have modifications to the same set of organs, but you can recognize homologous structures between both sexes. Now, whether a female of a species has a functional clitoris in the sense that humans do may be a different question (i.e. does the female's clitoris in say, a badger, provide the same level of pleasure as it does in humans) or if such structures in other species are entirely vestigal is another question. But I suspect you will find the structure itself, or one very like it, in all females of species where the male has a penis. --Jayron32 17:24, 17 March 2010 (UTC)

Our masturbation article has a lot of material about the original poster's latter questions, including an "Evolutionary utility" section and a "Benefits" section. Comet Tuttle (talk) 17:28, 17 March 2010 (UTC)

Gross. —Preceding unsigned comment added by 99.254.8.208 (talk) 05:19, 18 March 2010 (UTC)

Time Dilation

Does Gravity slows Time or makes it Fast? —Preceding unsigned comment added by 59.161.88.15 (talk) 17:07, 17 March 2010 (UTC)

A distant observer watching a clock that is near a massive object will see it ticking more slowly than a clock held by the observer. --Tango (talk) 17:09, 17 March 2010 (UTC)

So yes, gravity slows time down. --The High Fin Sperm Whale 17:19, 17 March 2010 (UTC)

Gravitational time dilation has a slightly less cryptic version of what Tango said: "the lower the gravitational potential (closer to the center of a massive object), the more slowly clocks run". Zain Ebrahim (talk) 19:40, 17 March 2010 (UTC)

***WP:OR alert *** Exception: The gravity of an urgent deadline will make time go faster, asymptotically faster the nearer one gets to it. Clarityfiend (talk) 20:09, 17 March 2010 (UTC)

So how fast does time go if you are alone in the universe (and exert no gravity on yourself)? —Preceding unsigned comment added by 99.254.8.208 (talk) 05:18, 18 March 2010 (UTC)

nitrogen temp

i have a bottle of nitrogen (nitro) for paintball and it hot if its full and cold when its near empty. why is this? once its released will it still be cold or hot or does it become room temp very fast? —Preceding unsigned comment added by Thekiller35789 (talk • contribs) 18:02, 17 March 2010 (UTC)

The ideal gas law (N2 can be considered an ideal gas) states that PV=nRT. V, your volume is constant, as are the variables n and R, so P and T have a linear relationship. Thus the higher P (pressure), the higher T (temperature) and v.v. Googlemeister (talk) 18:09, 17 March 2010 (UTC)

(ec) Per the ideal gas law, pressure and temperature are directly proportional to each other. In this case, as pressure drops (as you expend the nitrogen cartridge), the temperature of the gas drops, too. This then cools the cartridge itself. If you let the cartridge sit (either pressurized or unpressurized) it will move towards room temperature. — Lomn 18:12, 17 March 2010 (UTC)

Another way to think about this is that as the gas expands and does work (accelerating the paintball and pushing against the atmosphere), the gas loses thermal energy, and is thus colder. It will become room temperature eventually, (probably within hours, depending on the size and material of the bottle). Buddy431 (talk) 20:18, 17 March 2010 (UTC)

See adiabatic cooling. --Jayron32 20:22, 17 March 2010 (UTC)

Thanks, Jayron. I knew there was a more specific term than what I used, but it wouldn't come to mind. Now that mystery is solved! — Lomn 01:34, 18 March 2010 (UTC)

i have has this bottle for years and it does not change temp. is always hot or cold. —Preceding unsigned comment added by Thekiller35789 (talk • contribs) 21:26, 17 March 2010 (UTC)

That would violate the laws of thermodynamics. — Lomn 01:34, 18 March 2010 (UTC)

Not if it was always in a hot or cold environment :) Buddy431 (talk) 02:03, 18 March 2010 (UTC)

if you eat too much, will your body not digest it?

If you eat too much, so that you are stuffed, will your body not digest some of the extra food as normal? Also, insofar as it wouldn't, is the same true for someone who is "stuffed" because their stomach has shrunk due to their consistently eating very, very little, but after a long time of that routine, eating a (to them) very large meal? Thanks. 82.113.121.167 (talk) 18:22, 17 March 2010 (UTC)

Well, if you eat too much you will make yourself vomit and that food won't get digested. Other than that, I don't know of any reduced efficiency of digestion following excessive consumption. --Tango (talk) 18:28, 17 March 2010 (UTC)

That's interesting, it's not what I'd supposed. I'm not trying to quibble here, I'm not "asking for a reference" but it sounds like you have a better idea of what search terms to use than I would. Could you tell me how to use Google, what keywords and so on, to find something more formal to this effect? Thank you. 82.113.121.167 (talk) 18:44, 17 March 2010 (UTC)

I'm guessing what the OP should ask is if the body would run out of enzymes or stomach acid needed for digestion. I believe it just takes longer to digest and the body would keep on producing the necessary fluids. Digestion also takes a lot of energy, but I don't think the body would stop digesting because it's running low on energy. And yes, providing you can keep the food down. There IS a limit of how much you can stuff yourself based on stomach volume and how high the food can pile up in the esophagus. --Kvasir (talk) 18:46, 17 March 2010 (UTC)

My only thought is that a great amount of food will take longer to digest. If it truly went undigested then it wouldn't come out the other end in a radically different format. Vranak (talk) 19:25, 17 March 2010 (UTC)

If you eat a very large amount of vegetables, then it comes out quite green at the other end. Eating lots of vegetables is a good way to feel full without eating too many calories. 92.29.150.112 (talk) 19:58, 17 March 2010 (UTC)

I do think that the food will be less fully digested if you eat more than your digestive system can handle. For one thing, a few hours after you eat, your stomach contents will drain into the small intestine, pushing everything else along, whether it's been fully digested or not. For an extreme example, those who win international food eating contests typically lose the extra food in short order, out one end and/or the other. I think digestion efficiency also varies by person and by age, as some people can eat as much as they want without gaining weight, while others seem to gain weight if they eat even a little extra. StuRat (talk) 23:23, 17 March 2010 (UTC)

Cyclooxygenase-1 in thrombocytes

How much cyclooxygenase-1 does a single thrombocyte contain? Thanks in advance for the answers! Icek (talk) 19:02, 17 March 2010 (UTC)

Organic chemistry

What are the steps for making an anti-septic using parachlorometaxylenol,castor oil soap,pine oil,caramel,isopropanol and water. —Preceding unsigned comment added by 80.87.82.1 (talk) 19:04, 17 March 2010 (UTC)

"Mix" is the major one. Parachlorometaxylenol is the active ingredient, the others are the vehicle for making it into an easy-to-handle form with reasonable spreadability and concentration, minimal irritation or other side-effects, and enhanced activity. DMacks (talk) 19:22, 17 March 2010 (UTC)

Nothing posted here constitutes medical advice, or constitutes advice as to its safety or effectiveness. See [20] which is a book "Vanity, vitality, and virility: the science behind the products you love to buy" (2004) By John Emsley, found at Google book search by searching for the ingredients listed. The parachlorometaxylenol was first produced in 1923 and is also known as Dettol, (under which name we have an article) or PCMX, manufactured by Reckitt Benckiser. The article says it is sold as a 5% solution of PCMX with 5% pine oil, 14% castor oil soap, and 12% isopropanol, with the last 3 ingredients helping to keep the PCMX in solution. The ingredients listed only add up to 36%, so something else must be present. The manufacturer's data sheet for Dettol lists Chloroxylenol 4.8%. That seems to be a new name for the older PCMX, as a manufacturer's website suggests, and PCMX redirects to the article Chloroxylenol. (I've never understood why chemists give the same compound multiple chemical names. Is it like adding (then removing) tailfins to cars, or making neckties wider then narrower, or changing hemlines on dresses? Change for the sake of change, or new understandings of the molecular structure?). Edison (talk) 19:44, 17 March 2010 (UTC)

choking

is it possible that some people are immune to bloodchokes> i.e. (rnc) ? i take jujitsu and i have asked others to try to choke me unconscious and they were unable to do so. some have also used ropes. obviously eventually i would die because it also a oxygen choke (closes windpipe). but that takes over 1 minute. bloodchokes take no longer than 10 secs. they applied it for 40 secs. it was done by other jujitsu students —Preceding unsigned comment added by Thekiller35789 (talk • contribs) 22:00, 17 March 2010 (UTC)

I think this question might fall under a medical advice guideline; something to the effect of "consult a physician before beginning a rigorous martial arts training regimen where you might be subject to people choking you." Nimur (talk) 22:03, 17 March 2010 (UTC)

OP - do not ask your fellow Jujitsu students to choke you. Nobody, including yourself, is immune to hypoxia caused by a chokehold; if the hold is done correctly, it can seriously harm you. Nimur (talk) 22:04, 17 March 2010 (UTC)

lol, this is not medical advice. —Preceding unsigned comment added by Thekiller35789 (talk • contribs) 22:11, 17 March 2010 (UTC)

btw i saw an asphyxia vid of a woman doing a full suspension hanging on herself off a chair so it is possible she lasted 20 secs until her husband let her down she did not pass out thou you could HEAR her choking horribly so he let her down. —Preceding unsigned comment added by Thekiller35789 (talk • contribs) 22:14, 17 March 2010 (UTC)

The reference desk is not a forum. Your original question, "is it possible that some people are immune to bloodchokes", has been answered: it is not possible. If you have additional science questions, that is fine. If you would like to discuss asphyxiation in general, this is not the appropriate venue. Nimur (talk) 22:17, 17 March 2010 (UTC)

i dont wish to discuss "asphyxiation in general" my question was not answered. simply stating "no" is not an answer. how do you explain what iv stated ? —Preceding unsigned comment added by Thekiller35789 (talk • contribs) 22:28, 17 March 2010 (UTC)

"No" is an answer. Maybe the people trying to choke you out were doing it wrong or they did it wrong on purpose because they realize how utterly moronic it is to ask someone else to choke you into unconsciousness. 22:41, 17 March 2010 (UTC)Burpelson AFB (talk)

Unless you've somehow managed to find an alternate way to oxygenate your brain, then no, no you are not immune to lack of bloodflow to your head. They did it wrong. --M^ask? 22:44, 17 March 2010 (UTC)

they were black belts they didnt "do it wrong" —Preceding unsigned comment added by Thekiller35789 (talk • contribs) 22:47, 17 March 2010 (UTC)

people have variations in the musculature and other structures of the neck, as well as differences in the circulatory system more generally (due to physical development or genetics) that can impact on their susceptibility to this. all this act involves is blocking off blood flow through the carotid artery to a sufficient extent to starve the brain of oxygen, inducing a faint. if the person doing it fails to block off a sufficient amount of blood (because the artery isn't where expected, or is protected by muscles, or has a higher than normal amount of blood pressure, or...), the effect won't happen. Someone expert in the technique can likely overcome any such problems to make it work regardless.

that being said, you're an idiot. even sub-feinting episodes of oxygen deprivation can cause an amount of brain damage. further, your fixation on this issue is problematic - I am thoroughly surprised that your sensei hasn't beaten your ass but good over this, and I disrespect him because of it. I suggest that you tell him immediately that you have been practicing potentially lethal techniques without cause or supervision, and if he doesn't have you scrubbing the dojo for the next six months I suggest that you drop him and find a teacher who is capable of teaching you proper discipline. --Ludwigs2 22:49, 17 March 2010 (UTC)

Who cares if they were "black belts"? Even Pat E. Johnson does something wrong from time to time. You've had your answer, if you don't like the free answers, ask for a refund. Or, if you would rather hear "Yes, you're so manly that you can't be choked out" I'm willing to accept $10. You could even quote me. Burpelson AFB (talk) 22:58, 17 March 2010 (UTC)

They did, in fact, 'do it wrong'. If the desired result is to block off oxygen to your brain and make you pass out, which you did not do, then they, by definition, did it wrong. You dont have metal blood vessels. --M^ask? 22:57, 17 March 2010 (UTC)

for one thing my teacher is fine with it. we do it in class to each other occasionally. secondly the vid i mentioned which i can link if you want proves this is possible. im looking at this from a scientific viewpoint. if a rope is choking someone and their dangling in the air thats about as tight as it going to get. —Preceding unsigned comment added by Thekiller35789 (talk • contribs) 23:25, 17 March 2010 (UTC)

then your teacher is an idiot to. your behavior shames him, shames your school, and shames you. with that, I'm closing this question. --Ludwigs2 23:29, 17 March 2010 (UTC)

you dont have the right to close this, no one made you god. im honestly looking for a scientific explanation for this. you dont have any right to insult me. no one answered me about the hanging question.— Preceding unsigned comment added by User:Thekiller35789 (talk • contribs)

Like all harmful things, there is a spectrum of tolerance. Many factors, including exposure time, method of application of the hold, etc., will all affect how soon a person faints, suffers brain damage, and eventually dies. Because of the fatal nature of this subject, it is probably impossible to get an LD50 for choking time for humans. Here is a study on Inter and intraspecies genetic differences in survial to an acute hypoxic challenge in mice, rats, quails and chickens. As you can see, there is a scientific answer: this activity will result in brain damage and death. It is hard to say exactly how much force, or how many seconds, are required - for you, or for any "average individual." There will be outliers on each end of the spectrum, who survive longer or die sooner, due to many factors. For this reason, you should avoid participating in such an activity, because there is a real risk of permanent brain damage and death. If your martial arts teacher approves of such lethal play, he is not a very good instructor. Nimur (talk) 00:28, 18 March 2010 (UTC)

well generally it takes 5-10 secs to go to sleep, if the hold is held after 3 minutes their will be brain damage and if it is still held after ten minutes there can be death. it is safe as long as they let go after you pass out. but im not hear to talk about safety. what i want to know is how that woman was still conscious after 20 secs of FULL suspension hanging. —Preceding unsigned comment added by Thekiller35789 (talk • contribs) 00:51, 18 March 2010 (UTC)

That's nonsense. Victims do not "go to sleep", they fall unconscious. Whenever you lose consciousness, there is a significant risk of permanent brain damage. Nimur and Ludwigs are right. Your teacher is an idiot. "That women" probably did not have her carotid artery closed, but only choked. It's fairly easy if not always pleasant to do without breathing for 20 seconds. --Stephan Schulz (talk) 01:00, 18 March 2010 (UTC)

In judo class I was choked into unconsciousness numerous times, And it did not affect me. me. me. Edison (talk) 03:44, 18 March 2010 (UTC)

how do you not have your carotid artery closed from FULL suspension hanging. thats as tight as it gets

Well, it depends on a couple factors, including the weight of the person, and the physiology of their circulatory system in their neck. You'd probably be interested in our article Hanging, and see this page on hanging for more information on suspension strangulation. According to that, it's normal to struggle for 1-3 minutes, if the person is hanged without a drop. Indeterminate (talk) 03:11, 18 March 2010 (UTC)

yes, i already read those the second link you gave is not a reliable source as it states "the prisoner died "almost without a struggle” and they would be seen to writhe in pain for just a few seconds, if at all, before going limp." in the same paragraph. getting chocked out is not supposed to take 1-3 min. as seen here http://www.youtube.com/watch?v=SnkSxIMGTPU&feature=related —Preceding unsigned comment added by Thekiller35789 (talk • contribs) 04:59, 18 March 2010 (UTC)

i should also note it only takes 10 pounds of pressure the close the arteries in the neck. (the same to break a egg) —Preceding unsigned comment added by Thekiller35789 (talk • contribs) 05:25, 18 March 2010 (UTC)

Why should you note that? This is a reference desk, not a forum for frankly mastubatory postings about choking. You appear completely unwilling to accept any answer that has been given to you. I suggest whatever purpose this question had has now been served. --Tagishsimon (talk) 05:29, 18 March 2010 (UTC)

don't we want to use non-nucleophilic base to form epoxides? (unwanted diols)

Why do our articles mention potassium hydroxide as a base catalyst when halohydrins or epoxides are attacked? Isn't t-butyl hydroxide a better choice? The hydroxide also seems quite likely to react with the halide on the halohydrin (forming a diol). It seems that even when you do form the epoxide, it would get hydrolysed to form a diol. John Riemann Soong (talk) 22:03, 17 March 2010 (UTC)

t-butyl hydroxide is tert-Butanol, which isn't much of a base at all, being an alcohol, it will not have much of an affect on base-catalyzed reaction. Organo-metallic (Grignard) t-butyl reagents are very strong bases, like tert-Butyllithium, but these are so strong that they will actually do a very different set of reactions. If you are looking for a hydroxide-like base which is stronger than potassium hydroxide, then perhaps something like sodium amide may be better. --Jayron32 01:41, 18 March 2010 (UTC)

See Non-nucleophilic base for some options. You don't want any kind of hydroxide, because OH⁻ is the nucleophile causing trouble. This is assuming your guess is right, and you don't end up with much of your desired product — maybe the reaction does work fine with KOH, in which case your question will change to "why doesn't it cause problems?".

Give us a concrete example (or a link) and we can discuss it.

Ben (talk) 04:31, 18 March 2010 (UTC)

Err, I meant t-butyl O- (I guess I meant to say tert-butyl alkoxide). I was looking at the synthesis of epoxides and also epoxide#reactions. Why is a nucleophilic base okay here? John Riemann Soong (talk) 05:12, 18 March 2010 (UTC)

AAAAHHH! Tert-butoxide is a different story. In that case, yes, tert-butoxide is very good base, it prefers the E2 elimination mechanism over substitution (see Elimination reaction and Nucleophilic substitution) due to its high pKa. See Potassium tert-butoxide for some applications. So that may solve your diol problem. --Jayron32 05:30, 18 March 2010 (UTC)

Yeah but I guess my question is -- why aren't you required to use a non-nucleophilic base? (I haven't worked with epoxides in the lab yet so I have no practical experience in this area).

Also side question -- why is potassium tert-butoxide more popular than sodium tert-butoxide? Isn't the sodium species cheaper? John Riemann Soong (talk) 05:38, 18 March 2010 (UTC)

New York State Regions

Which regions of New York show evidence that crustal uplift was dominant over erosional forces in the past? Please help me answer this question.--Lamb99 (talk) 23:47, 17 March 2010 (UTC)

I came from a region in New York where the erosion from the last glaciation created great gorges and scars, the Finger Lakes and Watkins Glen, among others. Here's a hint: look at a topographic map of New York State (like this one), and find places where you do not see such glacial erosion. Crustal uplift is part and partial to orogeny - mountain building - so look for parts of the Allegheny Plateau, Catskill Mountains, and Adirondacks which are less eroded than others. In addition to glaciation, there are a few key rivers in New York State - the Susquehanna River and Hudson River. The effects of water course erosion on a drainage basin are dramatically different than a glacial receding scar. Nimur (talk) 00:15, 18 March 2010 (UTC)

Isn't there also crustal uplift from the weight of a glacier being removed, to maintain isostatic equilibrium? —Preceding unsigned comment added by 66.133.196.152 (talk) 04:35, 18 March 2010 (UTC)

March 18

Wild bird with a foot band

Weird. I was sitting in my backyard and I saw a wild sparrow with a metal foot band. I'm guessing it didn't put it on its self. How did it get on there? 198.188.150.134 (talk) 01:29, 18 March 2010 (UTC)

I imagine it was Bird ringing. Never knew it was called that before--Jac16888^Talk 01:33, 18 March 2010 (UTC)

That was a very interesting read, thanks for linking to that article. But I fail to see why researchers would add this tag onto a mere sparrow. I'm pretty sure they already know the migration patters of sparrows, and I don't see how it would be practical to count the population of sparrows, I mean , there must be hundreds of thousands of sparrows, there's no way you can catch that many and be sure you've got them all. 198.188.150.134 (talk) 03:25, 18 March 2010 (UTC)

I found it pretty interesting too. Maybe keep an eye out for it, it might still be around, and see if you can get a close up picture of its band and find out who tagged it. Also, found this link [21] which says its for determining survival rates and populations--Jac16888^Talk 03:34, 18 March 2010 (UTC)

To 198...: You'd be surprised. They tag all sorts of animals, even those that aren't endangered, and keep track of them for the very good reason that they can't know if there is or isn't a problem unless they keep track. Yes, there are lots of sparrows, but they need to know exactly how many is "lots" and if there start to be less, they can stay ahead of the problem. They need baseline numbers of populations to know when something does go wrong. And they aren't trying to tag them all. They tag a representative sample each year, and then see how many tagged animals they catch from year to year. If they tag a constant number every year, and the number they get back is steadily declining, then they can get info on the whole population. --Jayron32 03:51, 18 March 2010 (UTC)

has anyone ever been born completely reversed?

I don't mean dextrocardia, but a more complete reversal, including heart, liver, etc. Has it happened? If not, could it? Why or why not? This is not homework. 82.113.121.93 (talk) 01:40, 18 March 2010 (UTC)

Evidently, as the dextrocardia article links to Situs inversus, affecting "less than 1 in 10,000 people". Apparently, Randy Foye has it, and gets along just fine. Buddy431 (talk) 01:59, 18 March 2010 (UTC)

Inflation (cosmology)

Can Inflation (cosmology) be thought of as Refractive index just as various materials like water, air and glass are thought of in terms of their effect on the speed of light since such materials in effect impose the effect of inflation (cosmology) upon the speed of light due to their refractive index? -- 71.100.11.118 (talk) 01:42, 18 March 2010 (UTC)

No, it can't. Dauto (talk) 03:29, 18 March 2010 (UTC)

The how do you explain that in the absence of inflation the furthest source of light would be 13.7 billion light years away whereas with inflation it appears to to have traveled for 43 billion years just like light through glass appears to take longer than light through a vacuum? 71.100.11.118 (talk) 05:10, 18 March 2010 (UTC)

During inflation space/time expanded at far greater than the speed of light. But I'm pretty sure that's not all of it. According to observable universe we can see more than 13.7G light years because of the expansion of space. I take it as this (but I'm not a cosmologist, astrophysicist or astronomer): Star 10G LY away throws out some light, at some point in the 10 billion years the light spends travelling towards us, space expands putting the star an extra 10G LY away, so we see a star 20G LY away (also the wavelength of the light has doubled in that time). Perhaps inflation gave it a head start, too, with ultra-super-fast expansion of space. --Polysylabic Pseudonym (talk) 06:24, 18 March 2010 (UTC)

Trains

Are there any electric freight trains?

Are there any monorail freight trains?

Are there any maglev freight trains?

The Mysterious Person (talk) 01:56, 18 March 2010 (UTC)

Yes, no and no as far as I can tell. The only proof of any of these methods that I can find is the electric freight train through Google. Regards, --—Cyclonenim | Chat  02:16, 18 March 2010 (UTC)

What route does the electric freight train take on its journey through Google? Edison (talk) 03:41, 18 March 2010 (UTC)

^{Left at I'm feeling lucky station. Regards, --—Cyclonenim | Chat  03:44, 18 March 2010 (UTC)}

Purpose

Does any action other than those done by conscious beings have a purpose or are they just reacting to the laws of physics? —Preceding unsigned comment added by 99.254.8.208 (talk) 05:16, 18 March 2010 (UTC)

Science really can't answer that. See teleology. --Trovatore (talk) 05:19, 18 March 2010 (UTC)

Thank you. On a tangentially related topic, do single-celled organisms do things on purpose? 99.254.8.208 (talk) 05:40, 18 March 2010 (UTC)

There is no contradiction between having a purpose and reacting to the laws of physics. A "purpose" is a label attached to certain types of activities in order to make them easier to predict and understand, namely activities that can be understood as promoting some goal. Currently the only systems we know that can usefully be described in terms of purpose are organisms that result from natural selection, and devices that those organisms have created. Looie496 (talk) 05:41, 18 March 2010 (UTC)

On purpose? Some single celled organisms can follow scent trails to food; can cooperate with others to form colonies. Some pathogenic single celled organisms can cooridinate attacks through quorum sensing. Is sensing something and reacting to is "purpose?". In fact, are "conscious" humans doing any more? Perhaps the Humanities desk can offer a better answer to this philosophical question. --Polysylabic Pseudonym (talk) 06:34, 18 March 2010 (UTC)

Multiverse

Can you get to another universe by physically traveling in 3D space out of the area resulting from the big bang, or would you have to travel in a different kind of "direction" to get there? —Preceding unsigned comment added by 99.254.8.208 (talk) 05:34, 18 March 2010 (UTC)

I'm not sure actual scientific theories of "Multiverses" work in the way you seem to think they do. You may want to read Multiverse and Many-worlds interpretation and the works of Hugh Everett III and Max Tegmark. Any actual discussion of parallel universes is purely speculative and without experimental verification. Such possible universes are perfectly consistant with current understandings of how our universe works, but there is also nothing in the current theories that requires them, so by Occam's Razor, there generally isn't much use for hypothetical alternate universes in the current theory. --Jayron32 05:45, 18 March 2010 (UTC)