The printable version is no longer supported and may have rendering errors. Please update your browser bookmarks and please use the default browser print function instead.

Science desk
< December 15	<< Nov \| December \| Jan >>	December 17 >

Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

December 16

pyramid power

does anyone know the official site for this gym equipment hosted by brooke burke on TV? could it have made my abs not aligned?

are you suggesting thats a bad thing? abs that are built but not aligned are pretty sexy. they look more rugged and natural ;)

Explosives

Why is TNT usually used as a unit of energy or explosive power? For example, the recent nuke test in North Koria was classified as a "sub-kiloton" explosion, meaning the explosion was smaller than that of a kiloton of TNT. Is it because TNT is the most explosive (exluding nukes) or because it's widely available or what?

Also does any one have some stats on how other explosive compare with TNT (in eplosive energy-per-mass), particularly: C4, nitroglycerin, gun powder, fine black powder.

See relative effectiveness factor for an list of explosives compared with TNT by mass. grendel|khan 01:47, 16 December 2006 (UTC)[reply]

As to the first question, I think it's just that in 1945 TNT was one of the widely known and widely used explosives. --Anonymous, December 16, 03:50 (UTC).

TNT equivalent was used for discussing nuclear weapons yields since 1945. The ability to detect the explosive yield of the first nuclear test (the Trinity test) was first calibrated against 100 tons of TNT, which is probably the source of the unit. It has since been standardized as a fixed number (see Ton#ton_of_TNT) for use in such discussions. They are used for nuclear weapons out of convention, and are continued as such for comparative purposes. --24.147.86.187 22:56, 16 December 2006 (UTC)[reply]

It was from the calibration, and picked for that calibration beacuse it is the most widely used high explosive. It's not the highest however, fat holds 15 times more useable energy. 08:43, 21 December 2006 (UTC)

What sort of apple was this?

My father was recently given what looked like an apply by a patient of his. I believe it may be a fruit of Korean extraction. It was like an apple, but larger--about grapefruit-sized--and the skin was brown and rough. The inside was textured more like a pear than an apple, and it tasted very faintly of starfruit. We kept it for nearly a week before eating it, but it was still very crisp. It came in a webbed-styrofoam sheath. What sort of apple was it, if it was indeed an apple? (None of the other pomes look likely. grendel|khan 01:42, 16 December 2006 (UTC)[reply]

Everything but the skin sounds like a asian pear. Anchoress 01:53, 16 December 2006 (UTC)[reply]

Sounds like a quince.

Large intestine

I ve heard the main function of the large intestine is to remove liquid from the er, mixture! How does this water get extracted and then get passed to the kidneys for excretion?--Light current 01:50, 16 December 2006 (UTC)[reply]

"Water, as always, is absorbed in response to an osmotic gradient. The mechanism responsible for generating this osmotic pressure is essentially identical to what was seen in the small intestine - sodium ions are transported from the lumen across the epithelium by virtue of the epithelial cells having very active sodium pumps on their basolateral membranes and a means of absorbing sodium through their lumenal membranes. The colonic epithelium is actually more efficient at absorbing water than the small intestine and sodium absorption in the colon is enhanced by the hormone aldosterone." [1]. The water enters the bloodstream, which passes through the kidenys. - Nunh-huh 01:55, 16 December 2006 (UTC)[reply]

Aha so it goes back into the blood stream. Presumably the water level in the blood is controoled by the kidneys. Thanks--Light current 02:00, 16 December 2006 (UTC)[reply]

Correct, and we didn't even need to ask Colon Powell. StuRat 04:31, 16 December 2006 (UTC)[reply]

Hmmm. Its Colin actually.--Light current 04:35, 16 December 2006 (UTC)[reply]

He was being humerus. BenC7 07:00, 16 December 2006 (UTC)[reply]

If people don't get my jokes, perhaps I need to bone-up on my delivery. StuRat 13:38, 16 December 2006 (UTC)[reply]

I don't think I can stomach any more of these bile puns! La ï ka 20:12, 19 December 2006 (UTC)[reply]

Natural Resources

What are five natural resources of Japan?
What is the main source in the country of Japan?
Do people excise there in Japan?
When does education start, age, and type of training goes on there?

Were may I find these tpyes of answers?02:31, 16 December 2006 (UTC)

Thank you, Lisa 02:31, 16 December 2006 (UTC)~

Hi, Lisa. Try reading the article on Japan, following the links, and then getting back to us if any of your questions remain unanswered? Good luck. Anchoress 02:34, 16 December 2006 (UTC)[reply]

Some clarifications please:

What is the main source in the country of Japan? - Main source of what ? StuRat 04:29, 16 December 2006 (UTC)[reply]

Do people excise there in Japan? - Are you asking about an excise tax or exercise ? StuRat 04:29, 16 December 2006 (UTC)[reply]

The article Japan should give you many facts. If not, you may need to think whether the students in Japan do their own homework :-) --WikiCheng | Talk 10:16, 16 December 2006 (UTC)[reply]

They do! I've been there!X [Mac Davis] (DESK|How's my driving?) 23:22, 16 December 2006 (UTC)[reply]

What are opioid relative potencies? to morphine?

I've been wondering this lately. How do the many opioids relate to a standard - such as morphine? What is the statistical data that can tell me this, how is it measured - in-vivo? I stumbled across some non-cited powerpoint presentation over at [2] but other than that, I don't know where that information comes from, and haven't been able to find anything with a simpler chart of the relation, so I figured someone might know more than I at the health reference desk. Thanks. Edit: Mostly oral ingestion, but intravenous would also be interesting. - x1987x^(talk) 05:07, 16 December 2006 (UTC)[reply]

That's a fairly standard chart of the sort which can be found in pharmacology texts. Generally they are made from research on rats (in which the rat is given a certain dose of one of the opiates and subjected to painful stimuli). Note that the information is specifically about potency in its technical definition: it relates to the amount of analgesia produced by a certain weight of the drug. This is important when trying to replace one drug with another, but not terribly important otherwise. The common use of the term potency relates to "effectiveness", or the amount of analgesia provided by a safe dose of the medication, and the table doesn't speak to that at all. You don't care how many milligrams you have to take, only that the dose you need to take is safe. - Nunh-huh 23:10, 16 December 2006 (UTC)[reply]

Are there any more reliable links to said charts available online? Perhaps comparing a larger number of opioids? --x1987x^(talk) 00:11, 17 December 2006 (UTC)[reply]

There are numerous charts, with different opioids, depending on the availability of the substance in the country of origin. The term to search for is "opioid conversion table". Apart from that, pharmacological reviews of individual opioids usually give a strength relative to morphine. I'll get back in the morning (now 02:00 here). But thanks, this does sound like a suitable subject for an article. --Seejyb 23:08, 17 December 2006 (UTC)[reply]

I couldn't figure out the search term, thanks. Yeah, strengths of the many opioids aren't talked about much. And I had no idea where to look for such tables, let alone build a page from them. Thanks..--x1987x^(talk) 02:42, 18 December 2006 (UTC)[reply]

INvestigatory project

What is an investigatory project?

I don't think that phrase has any special meaning: it's simply a project designed to investigate something. —Keenan Pepper 05:54, 16 December 2006 (UTC)[reply]

Could be a preliminary phase like a feasibility study--Light current 00:59, 17 December 2006 (UTC)[reply]

Copper gluconate in breath fresheners

Why do Listerine PocketPaks contain copper gluconate? —Keenan Pepper 06:19, 16 December 2006 (UTC)[reply]

Retsyn. --W o o ty Woot? contribs 10:32, 16 December 2006 (UTC)[reply]

there is copper gluconate in retsyn - yes - but why?87.102.4.180 12:35, 16 December 2006 (UTC)[reply]

"The hydrogenated vegetable oil and the copper gluconate absorb odors in the mouth". --W o o ty Woot? contribs 03:59, 17 December 2006 (UTC)[reply]

Is copper gluconate an anti-bacterial - I thought that bad breath was due to bacteria?87.102.4.180 12:37, 16 December 2006 (UTC)[reply]

Good question, I don't know. It looks as if this compound is geared more toward absorbing odor than attacking the root cause. --W o o ty Woot? contribs 03:59, 17 December 2006 (UTC)[reply]

Wow. Learn something new every day. I had always assumed that "Retsyn" was pine tar, as in retsina. --Trovatore 04:05, 17 December 2006 (UTC)[reply]

examples on elasticity,plasticity and brittleness

Glass (brittle), rubber (elastic), and wet clay (plastic). StuRat 07:18, 16 December 2006 (UTC)[reply]

Waste water treatment

informations on use of electrophoresis for wastewater recycling

what are the sizes of particles removed in primary,secondary and tertiary treatment of wastewater? —The preceding unsigned comment was added by Chirag111 (talk • contribs) 09:09, 16 December 2006 (UTC).[reply]

what is the size of particles which can be removed from the wastewater by electrophoresis? —The preceding unsigned comment was added by Chirag111 (talk • contribs) 09:13, 16 December 2006 (UTC).[reply]

then could u please tell me the type size of particles removed during electrophoresis of sewage water?? Chirag111 09:37, 16 December 2006 (UTC)[reply]

This might help, especially the last paragraph. --W o o ty Woot? contribs 09:38, 16 December 2006

thank you but it is not specific. I am in an urgent need for the size of particles removed buring different processes of wastewater treatment. Chirag111 09:43, 16 December 2006 (UTC)[reply]

Typically the first treatment removes the largest particles, the second smaller particles, and the third would be a very fine filter.87.102.4.180 14:52, 16 December 2006 (UTC)[reply]

Or for a much better answer look at Sewage treatment which goes into a lot of depth.87.102.4.180 14:54, 16 December 2006 (UTC)[reply]

Bio-gas

what is the calorific value of biogas? how much of water can it heat?

what are the main constituent of biogas?

A note here, the refdesk is not Google. We can't give you "general information" about things, and if you're looking for information on biogas, we have an article on it. If you're going to ask more than one question, put them in one header. (I fixed this) --W o o ty Woot? contribs 09:22, 16 December 2006 (UTC)[reply]

No, Wooty, only related questions should be under the same section. StuRat 13:27, 16 December 2006 (UTC)[reply]

True, but 7 sections about the same thing is probably best consolidated as much as possible. --W o o ty Woot? contribs 03:57, 17 December 2006 (UTC)[reply]

I agree that similar questions from the same person should all be put in the same section, but dissimilar question should be posted separately StuRat 22:07, 17 December 2006 (UTC)[reply]

Applying general rules for articles to questions, comments and responses on the reference desk is inappropriate. Where the content of articles represent a consensus questions, comments and responses on the reference desk for many reasons do not. In fact, fooling around with other people's comments, questions and responses so that they suit your own 13 year old spoiled self is highly inappropriate and you need to stop. 71.100.6.152 20:16, 17 December 2006 (UTC)[reply]

Take it easy, now, Wooty was just trying to help. StuRat 22:08, 17 December 2006 (UTC)[reply]

Thats kind of hard to do when Wooty chooses a baseball bat to help keep the baby quite. 71.100.6.152 21:23, 18 December 2006 (UTC)[reply]

Also Wooty needs to learn that the purpose of the reference desk is to help others and to allow them to help each other rather than to indulge in the policies of one's 13 year old spoiled self. 71.100.6.152 18:16, 16 December 2006 (UTC)[reply]

To return to the question: Wikipedia's article is not helpful. Cleaned biogas has the same calorific value as natural gas. I do not have figures on boiling water, but I do have: 1 cubic meter of biogas can:

Yield enough electricity to light 60 -100 watt bulb for 6 hours
Cook 3 meals for a family of 5 - 6
Replace 0.7 kg of petrol
Run a one horse power motor for 2 hours
Generate 1.25 kilowatt hours of electricity

I will see if I have more info on exactly how the above is achieved, since it would be difficult to relate to water boiling. Maybe the last figure is the best to work with. The reference for above is a pdf file from the practicalaction.org site. Their technical information service page is a good place for finding further information. --Seejyb 21:57, 17 December 2006 (UTC)[reply]

1.25 kilowatt-hours is 4.5 million joules, since one watt-second is one joule. The specific heat capacity of water is 4.2 joules per gram per degree Celsius, meaning that it would take 4.2 joules to heat a gram of water by one degree. It would take 315 joules to heat a gram of water from 25 degrees to 100 degrees; therefore, 4.5 million joules can heat 14 kg (or 14 litres) of water from 25 degrees to 100 degrees.

Also, 71.100.6.152 and Wooty Woot seem to be in a conflict. Why? What happened? --Bowlhover 20:26, 18 December 2006 (UTC)[reply]

Wellbutrin & Zyban

In the article Bupropion it states: "Bupropion is both a dopamine reuptake inhibitor and a norepinephrine reuptake inhibitor."

Where can I verify this information? (I have added ^{[citation needed]} after that line in the article). Please reply. Thnx. --Delma1 10:59, 16 December 2006 (UTC)[reply]

Check some of the results of THIS GOOGLE SEARCH, one of which is the Mayo Clinic. Or THIS SEARCH OF GOOGLE SCHOLAR. Anchoress 11:06, 16 December 2006 (UTC)[reply]

Thnx for help Anchoress. Question Solved. --Delma1 11:24, 16 December 2006 (UTC)[reply]

TV reception

Why does a color TV program fade to monochrome when the reception is poor ? StuRat 13:33, 16 December 2006 (UTC)[reply]

Presumably you are talking about the old analogue TV system that is still used in some parts of the world like the US. I also assume you are talking NTSC? Look at Television, PAL and NTSC. I would have to look it up, but I believe it may be due to the reduced strength of the color sub carrier that is used for synchronisation of the color decoders. Also, there is only half the power transmitted for the chrominance signay compared to the luminance, so there is a 3 dB difference already present.

When there is no color sync signal, a circuit called a 'color killer' is switched on to avoid blotches of random color being displayed on the screen. This killer also operates in the case of simple monochrome transmissions. 8-) --Light current 14:46, 16 December 2006 (UTC)[reply]

Thanks, but I guess my question comes down to why the color signal is weaker than the monochrome in the first place. Was a decision made at some point that people would be willing to view a program without color, so the color signal should be given a lower priority and hence strength ? StuRat 15:21, 16 December 2006 (UTC)[reply]

Hey StuRat, it took a bit of reading, but here is the answer from the YUV Article:

Another advantage of YUV is that some of the information can be discarded in order to reduce bandwidth. The human eye has fairly little color sensitivity: the accuracy of the brightness information of the luminance channel has far more impact on the image discerned than that of the other two. Understanding this human shortcoming, standards such as NTSC reduce the amount of data consumed by the chrominance channels considerably, leaving the eye to extrapolate much of the color. NTSC saves only 11% of the original blue and 30% of the red. The green information is usually preserved in the Y channel. Therefore, the resulting U and V signals can be substantially compressed.

You also may want to check out: Luma (video), Chrominance, Chroma subsampling, and YIQ. --Cody.Pope 16:04, 16 December 2006 (UTC)[reply]

Thanks ! StuRat 16:13, 16 December 2006 (UTC)[reply]

Yeah its all about bandwidth really and cramming a quart (color + lum) into a pint(lum only) pot. THe eye is much less sensitive to color accuracy than brightness. Also to conseve bw, almost half of the am signal generated is supressed leaving only a 'vestigial' lower sideband. This keeps the channel width to about 6.6 MHz. Over here we used to call the US system Never twice the same color (NTSC) cos of its poor performance compared to PAL! --Light current 17:51, 16 December 2006 (UTC)[reply]

That's odd, because I've never had any trouble with the colors being wrong, only being absent. StuRat 19:27, 16 December 2006 (UTC)[reply]

YEs but as I said above, the eye is not very sensistive to colors 8-). Ever seen a PAL set? THats real color PAL! 8-)--Light current 19:32, 16 December 2006 (UTC)[reply]

Does this PAL stuff apply to computer monitors as well? I recently purchased a computer monitor named "Reflex" from a thrift store which I could not find any info for until I found a link in Europe and read somewhere that these monitors are not available in the USA. Could the PAL thing be the casue? Adaptron 20:50, 17 December 2006 (UTC)[reply]

Quote from our page on PAL:

Some engineers jokingly expand NTSC to "Never Twice the Same Color" or "Not the Same Color" while referring to PAL as "Perfect At Last", "Peace At Last", or "Pay for Additional Luxury"!

--Light current 21:00, 17 December 2006 (UTC)[reply]

No. To my knowledge, unless you have a UHF input to your monitor, then Pal is not relevant. PAL refers to phase reversal every line of the color subcarrier when transmitted. Your monitor will be RGB or composite video or some such thing and of course gives you much better picture than the TV- doesnt it?--Light current 20:55, 17 December 2006 (UTC)[reply]

Yeah. All of the computer monitors I've had have been better than tv sets except when I installed a tv card and it looked like a tv set. The thing is that this "Reflex" montior has superior color to everything except my lcd monitor. Its screen is a bit curved or rounded liek the very old monitors and when it comes back to life from a blank screen saver it takes a l o n g , l o n g time before the picture edges come back yo normal closer toward the center. Adaptron 19:47, 18 December 2006 (UTC)[reply]

Homologous vs Analogous

If I want to talk about two proteins, one in humans and the equivalent (related by evolution) protein in say, a mouse, are these proteins said to be homologous or analagous? --Username132 (talk) 14:15, 16 December 2006 (UTC)[reply]

Analagous proteins do the same thing in different organisms, homologous proteins are the same thing in different organisms. Droud 15:01, 16 December 2006 (UTC)[reply]

Are the same thing as in prisicely the same sequence, or the same thing as in same ancestor? --Username132 (talk) 15:22, 16 December 2006 (UTC)[reply]

You'll want to check out homology (biology). It's got a description of the different types of homology there. Gene sequences are (almost) never precisely identical from one species to the next; often you'll see discussions that describe the degree of sequence homology as a percentage. TenOfAllTrades(talk) 15:45, 16 December 2006 (UTC)[reply]

Homologous it is. Thanks both. Username132 (talk) 20:49, 16 December 2006 (UTC)[reply]

Your description would suggest they are actually orthologous proteins, to be more specific (assuming by equivalent you mean "the most closely related protein in the mouse"). Rockpocket 03:51, 17 December 2006 (UTC)[reply]

pill identification chart

Where can I find an online chart which shows photos and identification markings of prescription pills? John Howard —The preceding unsigned comment was added by Larryfassler (talk • contribs) 19:34, 16 December 2006 (UTC).[reply]

If you're trying to identify a pill that you've been given, this site lets you search on drug name, pill imprints, colour, and shape. It outputs a table of photographs of all the hits it comes up with. This site], meanwhile, lets you upload a picture of a pill and then you wait (and hope) for someone to identify it for you. (It's sort of like the Reference Desk here.) TenOfAllTrades(talk) 19:47, 16 December 2006 (UTC)[reply]