Wikipedia:Reference desk/Archives/Science/2006 July 30

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What species is a seagull with a gray band around its beak?

What kind of gull has is mostly white with gray on the wings, black tail feathers and a grayish-black band around its beak? I saw it at Misquamicut State Beach in Rhode Island. Is it a normal variation on the other gulls in the area (they had a reddish spot on the lower part of the beak; I don't know what kind they were), or a different species? If so, which species? grendel|khan 00:14, 30 July 2006 (UTC)

Where's KSB when you need him eh?

You called? :) Check out Ring-billed Gull, especially the third picture in the gallery at the bottom. Look like the fellas you saw? --Kurt Shaped Box 00:57, 30 July 2006 (UTC)

Like twins, except that mine has no spots on the head---it's uniformly white. Is it still the same bird? grendel|khan 01:45, 30 July 2006 (UTC)

Most probably. The adults of many species of gulls have dark feathers (streaks/spots) on their heads in winter. The all-white head is the breeding plumage. --Kurt Shaped Box 01:51, 30 July 2006 (UTC)

There he is. --Proficient 19:02, 1 August 2006 (UTC)

Einstein's attempted T.O.E.

Hello, and thanks in advance. I know that Einstein worked on a theory of everything, and worked with Rosen on it, and postulated that particles were small worm holes. My question is, what was this theory called? I tried searching, but i wasn't able to find it. Any help will be apreciated. --AmateurThinker 00:17, 30 July 2006 (UTC)

Einstein and Rosen's activity together was not concerning a theory of everything, however what you are looking for is probably at Einstein-Rosen bridge or their work regarding the EPR Paradox.

Einstein's own TOE was simply known as the unified field theory. --Fastfission 03:01, 30 July 2006 (UTC)

Thank you, but all I wanted to know was what the postulate of particles being Einstein-Rosen Bridges was called. AmateurThinker 22:48, 30 July 2006 (UTC)

Diving fitness requirements

what are the fitness components for diving inorder of importance

Please do your own homework. The answer you are looking for probably came from your teacher or textbook. The question is too vague if otherwise. Also, try our diving article! Thanks,

Gulls - carnivores or omnivores?

I've just been reading a few of the gull articles on Wikipedia (swatting up on my specialist subject - heh). I notice that in some places gulls are described as omnivores, in others carnivores. Anyone know which one is technically correct? I'd personally lean more towards 'carnivore' as gulls are, by nature meat eaters. They were 'designed' to scavenge from carcasses and prey on small mammals/birds/fish - one look at the beak shape and the observation of a gull's aggressive demenour should tell you that. The fact that they have learned to feast on whatever we throw out, be it animal, vegetable or mineral is neither here nor there IMO. Any thoughts? I think the definition needs to be standardized across the articles... --Kurt Shaped Box 00:23, 30 July 2006 (UTC)

No expert here, but I'd say if an animal will eat both meat and non-meat foods (and can actually digest them) it is an omnivore. So you could turn this around and say that the fact that some gulls only eat meat doesn't necessarily mean they aren't omnivorous. DirkvdM 09:07, 30 July 2006 (UTC)

(after edit conflict) The fact that some gulls have learned to eat other stuff does seem relevant, because those that come and finish off a pizza are omnivores, while those who spend their life at sea and eat only fish are carnivores (or ichthyophagists, if you prefer). --Shantavira 09:11, 30 July 2006 (UTC)

Is that the same as a piscivore: [1]? StuRat 04:49, 31 July 2006 (UTC)

Blah - fish *is* meat. Don't let those damn veggies convince you otherwise... ;) --Kurt Shaped Box 15:26, 31 July 2006 (UTC)

Well, so are insects, but biologists still insist on treating insectivores as distinct from carnivores. —Ilmari Karonen (talk) 19:50, 31 July 2006 (UTC)

Are they really? I think of them more as exo-skeletons full of mucous. Is there really any meat in them? Maybe in grubs. Mmmmmm, all this talk has made me hungry!--Anchoress 20:07, 31 July 2006 (UTC)

What is the noun for 'mucous'? 'Muck'? You eat muck? DirkvdM 09:37, 1 August 2006 (UTC)

Or catholics. They also eat meat on friday because they claim it is not meat. DirkvdM 09:37, 1 August 2006 (UTC)

Here, have some muskrat — it's tasty! —Ilmari Karonen (talk) 22:36, 1 August 2006 (UTC)

If you make that into a stew, would you get StewRat? DirkvdM 07:09, 2 August 2006 (UTC)

LOL. StuRat 20:30, 3 August 2006 (UTC)

Evolutionary relationship between skuas and gulls?

I'm aware that both the skua and gull family are members of order Charadriiformes - but how closely are they related? Did both have a common ancestor or did one family evolve from the other? I see great black-backed gulls on a daily basis and I have had the opportunity to observe the great skua and aside from the colouration, the similarities in size, shape and behaviour are uncanny. To a non-scientist, they seem like very closely-related birds indeed. Then again, compare the skua to the small, timid black-headed gull and they seem worlds apart. --Kurt Shaped Box 00:39, 30 July 2006 (UTC)

According to the tables in p.9 of the first reference in Charadriiformes, gulls are more closely related to skimmers and terns than to skuas. Skuas, for their part, might be more closely related to auks than gulls, but it's not clear. You might want to also check the refs in Lari. Melchoir 01:26, 30 July 2006 (UTC)

I've never been able to understand those tables - any tips? :) --Kurt Shaped Box 12:46, 30 July 2006 (UTC)

Just find the two families you want to compare. Start at one and just sort of walk back along the line until you get to a level from which you can reach the other family. When comparing how close family A is to families B and C, see how far out you have to go to get from A to B, then from A to C. The farther you have to go, the less closely related the two families are (well, the less similar they are in whatever measure is being shown). I'm not sure I explained that totally well... :) digfarenough (talk) 15:10, 30 July 2006 (UTC)

Yes, but .........

You release a toy balloon and it flies around frantically. It will do so even in a vacuum (deep space for instance), because the pressure inside the balloon moves it away from the escaping air. If I have that right, then I think the Thrust article needs to make this clear, because unless you read it carefully it seems to infer/suggest that it is the expelling air that is pushing (on something outside the balloon). Pedants go away please, but would appreciate comment from others. Rense 00:42, 30 July 2006 (UTC)

This should go on Talk:Thrust. Yes, you're right. Newton was the one who declared this.Nathan Rosen

I would have thought that a toy balloon would immediately explode in deep space, and the air would ignore the fact that the neck was open. But if any air did manage to come out of the neck, the balloon would move away so that the centre of mass of all the air was preserved. G N Frykman 08:55, 30 July 2006 (UTC)

You're forgetting the mass of the balloon itself. So the centre of mass of the shreds of the balloon and of the air will move in opposite directions. DirkvdM 09:19, 30 July 2006 (UTC)

A balloon in space would be able to hold the same internal/external pressure differential that it does at ground level without exploding. The center of mass of the balloon and the gas in it would stay in the same place it started if you released it in space, except for gravity effects. A newspaper editor derided Robert Goddard, physics PhD, as "not having even a high school knowledge of physics" because Goddard thought rockets would work in space "where there was no air to push against." The space program proved Goddard right. Some things never change.Edison 17:30, 1 August 2006 (UTC). tjis is very true .best article

Feasability of man-portable miniguns...

Just trying to refresh my knowledge here. IIRC (correct me if I'm wrong here), a man-portable minigun would *just* be within the realms of possibility, right? Assuming that the gun itself weighs approx 100lbs and the ammo pack and batteries to spin the thing up were located in a backpack weighing approx 150lbs (I seem to remember those figures from an article on this subject I read years ago) and the soldier in question was selected specifically for his size, strength and endurance, then a minigun could potentially be used as an (albeit impractical in the majority of situations) infantry weapon, right? --Kurt Shaped Box 01:14, 30 July 2006 (UTC)

It sure is. Go out and rent Terminator 2: Judgment Day. Actually, rent the whole series. It's worth it. --mboverload@ 01:18, 30 July 2006 (UTC)

Yup, great movies - I've seen Predator too. :) I was thinking of the feasability of using a man-portable minigun for suppressive fire - a couple of 180-degree arcs of fire from a 2000RPM minigun towards a hidden foe (e.g. hiding in the undergrowth) would pretty much clear out everything, wouldn't it? Or at least cause them to retreat. Your own position would of course, have to be well-stocked. --Kurt Shaped Box 01:29, 30 July 2006 (UTC)

Indeed. I have never really thought about why miniguns are not in more wide deployment. Seems like a good thing to throw in the back of a hummer and get out when you have to hold a position. --mboverload@ 04:00, 30 July 2006 (UTC)

It isn't more widely used because you run out of bullets too fast. Which is mentioned in the article. Rmhermen 06:31, 30 July 2006 (UTC)

the logistics of resupplying the soldier in the field would be difficult, as well as the amount of ammunition the soldier would need to carry to make it an effective weapon, given a regular light machine gun firing at around 800 rpm carries upward of 1200 rounds, scaling that up would give an enormous weight. and you have to wonder whether there is any advantage over existing weapons, which i'd doubt. Xcomradex 09:23, 30 July 2006 (UTC)

I suppose. To take down an enemy soldier, you'd probably need to hit him with a quick burst from an assault rifle, just to make sure (unless you were a very good shot) - maybe four or five rounds. A direct hit from minigun fire would turn him into a pile of meat, which I guess is overkill and a waste of ammo. Going back to the Terminator movies (thinking of the future scenes), the use of miniguns against advanced robotic/cyborg infantry actually does make a lot of sense, considering the amount of damage that the endoskeletons can take and still function. In this case, tearing the enemy to shreds with a solid wall of fire would not only be advantageous - but entirely necessary. --Kurt Shaped Box 11:28, 30 July 2006 (UTC)

I believe I read under trivia in the Terminator 2 article that Arnold was the only one on the set that could lift the weapon--he had to move it everywhere.

Really? You'd think that they could have afforded to hire a couple strong college kids to haul it around the set. And think how cool it'd be to list your last job as "Mini-gun wrangler" on your resume.

hello pk how r y

Hookes Law?!?!?!!

Helllooo. Can someone tell me the simple idea of what Hookes Law is please. I'v already searched it but I just cannot get the bloody gist of it lol. - Thanks Joel

You've read Hooke's law, then. Where are you getting stuck? Can you be more specific? If you can't be, I'm afraid you'll probably just get the first paragraph of the article quoted at you. If we had a better way of explaining it, we'd put it there. grendel|khan 01:44, 30 July 2006 (UTC)

The more you pull something, the more it will stretch. (As long as it's a relatively "Hookean" material!)--Shantavira 09:18, 30 July 2006 (UTC)

Or perhaps "the further you pull on something, the harder it pulls back" --Bmk 12:43, 30 July 2006 (UTC)

Yup, to be even more exact, the force you exert of a body is proportional to the extension of the body. Think of a spring. The harder you pull (greater force), the longer the spring becomes (extension from 0). And the relation between the force you exert and the extension is proportional! Ask for any help =]

Retinitis Pigmentosa Gene Therapy

To date, what is the current state of gene therapy clinical trials for Retinitis Pigmentosa? (4.152.123.249 22:18, 29 July 2006 (UTC)).

Hello. I'm not an expert in the field, bit i had the pleasure of meeting a certain Professor Robin Ali, of the Institute of Ophthalmology, London, not so long ago and discussed his very impressive work. He is very much leading the way in gene therapy for retinal disorders. An overview of his work can be read here, some of his scholarly papers on animal models [2] [3] [4]. This source [5] (pdf) suggests that human trials are underway or planned for retinal diseases, but not RP specifically. This source [6] seems to suggest that human gene therapy for RP will be (or has been) tested. There is also more impressive work in dog models of Leber congenital amaurosis, according to these sources [7] [8] human clinical trials for RPE65 gene therapy were targeted to begin in 2006. It is probably a bit early to know how successful these have been. Rockpocket 03:40, 30 July 2006 (UTC)

How many calories??

Ive been reading the Calorie page and also reading up on Atwater system to calculate food energy values. But im wondering, is there a way or a formula to see how much a certain body mass (a person) is burning calories just by its normal functions, sleeping, breathing, pumping blood, other. So a person that weighs x kilos and its height is y cm, burns z calories during a 24 hour period. - Avalean - 30th July

There are things like that on the net, but they're not very accurate, because basal metabolism (resting metabolism) has many other variables besides body size. For instance, men and women of the same mass usually differ; people with higher fat percentages or higher muscle percentages; hormonal imbalances can change a person's metabolism. I've seen charts on the net but I hesitate to find them for you because I don't think they'd really be accurate. That having been said, we have an article on Basal metabolism that probably answers your question, although the article is tagged for needing cleanup, and the main formula mentioned says something about surface area of the body (sq m.) when I'd think it should be cubic metres, but what do I know? I just skimmed it anyway. But I noticed the article has some external links. Happy reading.--Anchoress 03:15, 30 July 2006 (UTC)

Anchoress is correct in stating that any simple height/weight/sex/age formula is going to have poor accuracy (I'd guess +/- 20% for people in the "normal" ranges of activity, size, etc.). You could try the Harris-Benedict Equation, it's a classic. -- Scientizzle 21:47, 30 July 2006 (UTC)

The reclusive lady is right, I think. Mass (which is related more to volume than BSA) matters more than body surface area. The BSA theory stuck as gospel following some heavy abstract theorising in the 19th century, and Harris-Benedict sort of preached on, without questioning the basic tenets. It seems as if general biologists these days don't even consider BSA as a real factor, but doctors and dieticians and bodybuilding product sellers carry on regardless. I see on the Basal metabolic rate article talk that it gets 5th place on Google searches at times, but to me it is pretty dense and confusing - not comparable to what I see in academic literature on the subject. I suggest Avalean should look to one of the recent mass related formulas, ignore height, and remember that an individual is not a statistic, so that just a table of values by age and weight is probably as good/bad as any formula. --Seejyb 02:26, 31 July 2006 (UTC)

I seem to recall a method of calculating calories burnt by measuring the exact amount of heat given off by a person at rest, which should be directly proportional to the number of calories burnt. This test, of course, requires a laboratory and the proper equipment. StuRat 04:32, 31 July 2006 (UTC)

Thanks a lot - Avalean - 31th July

Stomach

Is it possible to live life without a stomach?--68.79.234.100 03:46, 30 July 2006 (UTC)

Actually certain people do it to some degree all the time. --mboverload@ 03:59, 30 July 2006 (UTC)

Not just to some degree (gastric bypass) but also entirely (prevention of stomach cancer). The surgeons fashion a small pouch out of the esophagus and intestine. People without stomachs have to eat many small meals throughout the day, and avoid foods that the intestine can't digest by itself. --Allen 06:01, 30 July 2006 (UTC)

A person can actually live quite a long life without the use of a gut on total parenteral nutrition. Essentially, the individual is "fed" a nutrient solution intravenously. – ClockworkSoul 19:30, 31 July 2006 (UTC)

Info about unexplained undersea sound

I recall reading a piece online (probably here at Wikipedia, actually, but not sure) about a very unusual sound that was recorded somewhere off the southern coast of South America. IIRC, it was called a burp or a belch or something of that nature. The article mentioned that some people think it may be the vocalization of some enormous creature. Can someone provide more info? I've searched Google and Wikipedia, but I don't recall a lot of specifics, which makes searching pretty difficult. ISTR that there was a site online that provided a .WAV of the sound as well. TIA. Matt Deres 04:19, 30 July 2006 (UTC)

The article is Bloop. Rmhermen 06:27, 30 July 2006 (UTC)

Thanks! Matt Deres 23:48, 31 July 2006 (UTC)

Bleep!!

Electricity

Who is the father of electricity?

Of electricity, you say? I haven't the foggiest. But good luck with your homework, in any case. grendel|khan 08:05, 30 July 2006 (UTC)

Thats subjective... Gerolamo Cardano, William Gilbert, Otto von Guericke, C.F. du Fay, William Watson, Benjamin Franklin, Ebenezer Kinnersley, Faraday, Volta, Ampère and Ohm could all have claims on that title. Such is the way the scietific method works; Take your pick. Rockpocket 08:06, 30 July 2006 (UTC)

(edit conflict x2) If you ask Google you get four different answers in the first 10 results: Benjamin Franklin, William Gilbert, Thomas Edison, and Ernst Werner von Siemens. The fact that there are only 364 hits for "father of electricity" suggests that no one is uniformly recognized by that title. Our own List of people known as father or mother of something, which should be fairly reliable, does not list anyone.

If you're trying to come up with your own answer, one starting point is Electricity#History. Melchoir 08:11, 30 July 2006 (UTC)

Lightning? And the mother would then be the 'ground' (mother Earth)? DirkvdM 09:25, 30 July 2006 (UTC)

But Category:Thunder gods has 43 entries... Melchoir 09:27, 30 July 2006 (UTC)

Strangely, this doesn't seem to be in our article List of people known as father or mother of something. If you find out, please add it.-gadfium 09:42, 30 July 2006 (UTC)

Nikola Tesla should be on the list too, if not as a father, then at least a great-Uncle or something.

I think Franklin and Tesla are the only ones that I have heard as "father of electricity."

Whoever it was, he was one bright spark. *gets coat* Rockpocket 18:17, 30 July 2006 (UTC)

Guglielmo Marconi was the father of Maria Elettra Elena Anna Marconi. -- Nunh-huh 04:55, 31 July 2006 (UTC)

And the father of Electra was Agamemnon. DirkvdM 09:06, 31 July 2006 (UTC)

InputStreamReader

--Tulika 99 11:34, 30 July 2006 (UTC) halow!! i wud like 2 ask what statement shud b used after

InputStreamReader reader=new InputStreamReader(System.in); BufferedReader buf=new BufferedReader(reader);

after this v usually use

V1=input.readLine(); int a=Integer.parseInt(v1);

but its not gettin compiled. can u plzz suggest another statement.

thnk u!!

A few possible problems (I assume this is java):

• You have not declared the string V1
• "input" doesn't exist - that line should be

V1 = buf.readLine();

• you may need to handle the IO exception from the readline statement
• java is case sensitive, so v1 is not the same as V1

fix one or more of those and you may be good to go. Here's what I think it should look like instead:

Add the phrase "throws IOException" after the argument parenthesis in the method head

       InputStreamReader reader = new InputStreamReader(System.in);
       BufferedReader buf = new BufferedReader(reader);
       String V1 = buf.readLine();
       int a = Integer.parseInt(V1);

You can also use a try/catch block, if you know how. Good luck --Bmk 12:34, 30 July 2006 (UTC)

thnk u soo much Bmk !!!!!!!!!

No problem. Enjoy java - it's my favorite. --Bmk 15:31, 31 July 2006 (UTC)

Is a seagull a 'vulture'?

Moved from Humanities.

I mean it acts like a vulture (circles, eats caracsses and carrion). If the vulture had been discovered before the seagull, do you think that explorers would've named the various breeds of seagull 'sea vultures' or something? New world vultures are not real vultures either but they're called that because they act like vultures and the name stuck over the years. What do you think?

Eh - seagulls do a fair amount of hunting and foraging - they kill and eat crabs and shellfish (see seagull). I don't think they eat enough carrion to qualify them as a vulture-type bird. Whoa - I'm surprised there are any gull species links that don't exist given the number of gull fanatics on the desks! --Bmk 12:53, 30 July 2006 (UTC)

Vulture is a whole seperate few families. I think I'll move this to Science.

The point I was (badly) trying to make is that the biggest seagulls fill the same niche in Northern Europe as 'vultures' do in Africa and 'vultures' do in N.America. The 'vultures' in N.America are only called 'vultures' because the first western people to see them thought they looked like the vultures they already knew about. If we define a 'vulture' as a "scavenging bird, feeding mostly on the carcasses of dead animals." as the vulture article does, then why are seagulls not classified as 'vultures' when they clearly fit the critera (in their natural habitat)? I reckon it's only because seagulls were discovered before vultures - if they didn't already have a name, they'd have been devined as 'vultures', I think. --84.67.154.51 17:19, 30 July 2006 (UTC)

By that rationale, on discovery vultures could, or should, have been named as a type of gull! Historically animals would be named by their lay-discoverers after animals they already knew about, usually based on single, or groups of, defining characteristics. This may have been because they actually thought they were closely related to these animals, or simply as a way of identifying them with some meaning. These days were know that convergent evolution can lead to highly divergent animal species (in terms of evolutionary relationship) appearing very much alike as they fulfil a similar niche. Since we continue to refer to most animals by their traditional names, it can get confusing. However scholarly studies use scientific names for animals, which better reflect their phylogeny. Old and new world vultures are a good example of this. Old World vultures (Accipitridae) are of the genera: Gypaetus, Gyps, Torgos, Aegypius, Neophron, Gypohierax and Necrosyrtes while new world vultures (Cathartidae) are of Cathartes, Coragyps and Sarcorhamphus. Seagulls are from a completely different order (Charadriiformes) Thus, scientifically, there is no confusion between them. Consider also the aardvark (earthpig) and Killer Whale. Rockpocket 18:46, 30 July 2006 (UTC)

They were really running out of ideas when it came to the wildebeest, weren't they? "Hmmmm - a wild beast. What should we call it?" :) --Kurt Shaped Box 21:31, 30 July 2006 (UTC)

I guess with all the good names already gone, they had to think up a gnu one.... Rockpocket 23:18, 30 July 2006 (UTC)

Not aganother g-nu joke. Please come back, Michael and Donald.  :--) JackofOz 06:18, 31 July 2006 (UTC)

Reoccuring question topics on Science

It seems like we get a lot of seagull and masturbation questions on here. Anybody else notice this, or is it some illusion I have fallen for?

If 15% ("72% of statistics are made up on the spot") of article edits are vandalism why wouldn't 15% of questions be from kids who think, "let's see if we can make grown-ups talk about flying rats and wanking". Don't mind it, just answer; even if the person asking doesn't learn anything from the answer the rest of us will. Weregerbil 18:33, 30 July 2006 (UTC)

I've noticed it as well, but why seagulls? If a kid wants to ask a silly question then giggle at the serious answers, why would he choose seagulls? Spanking the monkey, sure, but seagulls? Hyenaste ^(tell) 18:42, 30 July 2006 (UTC)

To be fair, most of the seagull questions are posted by one particular user. --Ginkgo100 ^{talk · contribs · e@} 18:48, 30 July 2006 (UTC)

Yeah, I agree with you on that. But, I think some of the other users cured him. ;-) Jayant,17 Years, India • contribs 21:07, 30 July 2006 (UTC)

Particularly funny is when there are a spate of very similar questions, often utilitising the word 'discuss', and you just know that some teacher has set a Wikipedia-savvy (well, savvy enough to know about it, but not enough to disguise homeword) class a particular problem. --Sam Pointon 21:16, 30 July 2006 (UTC)

In answer to all the above, what can I say? I'm a gull fanatic. :) I spend a lot of time observing my locals birds and I've decided that I want to know as much as it's humanly possible to know about them (much of the literature tells me about what gulls *look like* or where gulls can *be found*, but very little about the lives of the actual birds themselves). I've raised baby gulls almost from the egg to re-release into the wild - I think that they're amazing birds, with a strange charm that I don't think anyone else could possibly understand unless they'd done the same thing themselves. I know a fair bit about gulls already but my head is filled with questions, which some of the guys here seem able to answer for me (it's much appreciated - this desk seems to be one of the more knowledgable gatherings of human beings on the internet). I assure you that I'm not asking silly questions for the sake of asking silly questions, or for kicks and giggles. I have no idea who keeps bringing up masturbation - I can't say that I've noticed that many threads about it recently. --Kurt Shaped Box 21:19, 30 July 2006 (UTC)

You need to go to Wikibooks and write a book on seagulls to get them out of your system, since the elctroshock therapy has failed to do so. :-) StuRat 01:21, 31 July 2006 (UTC)

Your gull questions aren't silly though. Hmm... did you ask the unsigned gull question just above this one? If not, gull-mania must be catching on. Hyenaste ^(tell) 23:02, 30 July 2006 (UTC)

Not guilty, sir. Maybe I'm starting a movement... :) --Kurt Shaped Box 15:28, 31 July 2006 (UTC)

Maybe we can kill two birds with one stone (or at least make them go blind) by posting questions on the masturbation practices of seagulls ?  :-) StuRat 01:21, 31 July 2006 (UTC)

I only find one google hit for "masturbating seagull". --JWSchmidt 01:42, 31 July 2006 (UTC)

There's over 55000 for seagull + masturbation though. Hyenaste ^(tell) 01:45, 31 July 2006 (UTC)

Can Seagulls Masturbate?

Can Seagulls Masturbate? The answer is 42.

In small arms ballistics, how is "effective range" defined?

What does it mean for a rifle to have an effective range of 400m? Obviously a rifle bullet carries a dangerous amount of kinetic energy way beyond its effective range. And the probability that a target at a given range is hit in a single shot depends on many factors (e.g. marksmanship of the shooter, power of the scope, weather, size of the target). So, is there a standard definition for "effective range"?

It apparently depends on who is giving the value; it is not standardized. See this article on it, which I found by Googling "maximum effect range definition". --Fastfission 18:02, 30 July 2006 (UTC)

Would also depend on the effect you're after, I'd say. DirkvdM 09:18, 31 July 2006 (UTC)

in military terms, the effective range couples both the stopping power of the round, the velocity at that distance and the chance of hitting a target at that range. for example, in the NZDF, the effective range of the Steyr AUG was quoted as 300m, while that of the c9 lsw (a version of the FN Minimi) was quoted as much further, off the top of my head at least 600m. yet both fire the same round (5.56mm ss-109), but the c9 in normal use pumps out more rounds. Xcomradex 11:12, 31 July 2006 (UTC)

Railroads: Where are the breaks on a freight car?

In the past the breaking force and break shoes on a railroad freight car were applied to the wheel rim to slow or stop the car. I don't see that on today's (USA)rail freight cars. Where is the breaking force applied and what's the mechanism that stops the wheel from rotating?

The, um, BRAKES on a railroad freight car are part of the truck assembly. This document has a really nice exploded diagram of a railcar truck on the third page. The brake shoe contacts the tread of the steel wheel. There is one shoe per wheel, four per truck.

tread??

Yes, technically the shiny part of a railroad car's wheel is the tread. If you look at this picture the shiny part of the wheel that contacts the track, that part is the tread. The raised rim on the inner edge of the wheel is the 'flange'.

Hall Effect

cant we use hall effect in producing electricity ? high voltage supply cables on their way could b made 2 pass through tubes containing magnetic field.hence by hall effect potential difference would exist. but i doubt the high voltage cable would get weaker in voltage after passing through the tube. plz if anyone can explain it relating to conservation of energy and other phenomenons involved

---

Legend:

  1. Electrons (not conventional current!)
  2. Hall element, or Hall sensor
  3. Magnets
  4. Magnetic field
  5. Power source

In drawing "A", the Hall element takes on a negative charge at the top edge (symbolised by the blue color) and positive at the lower edge (red color). In "B" and "C", either the electric current or the magnetic field is reversed, causing the polarization to reverse. Reversing both current and magnetic field (drawing "D") causes the Hall element to again assume a negative charge at the upper edge.

I would suggest checking the article too. Hall effect

---

Since a violation of the law of conservation of energy isn't possible (unless mass was converted into energy, which doesn't happen here), the energy passing thru the tube must be reduced to a level to match any increase outside the tube. StuRat 01:12, 31 July 2006 (UTC)

I didn't read the entire post, but I saw this in it "but i doubt the high voltage cable would get weaker in voltage...." don't be so doubting. If that cable transfered any energy (via hall effect, or any other way) then yes, it would become weaker. By EXACTLY the amount that was transfered. 71.199.123.24 01:05, 1 August 2006 (UTC)

That's "at least the amount..." rather than "EXACTLY the amount..." --Polysylabic Pseudonym 11:08, 2 August 2006 (UTC)

Nope... the energy supplied to the electric potential comes from a change in the magnetic field. The wire loop must be moved through the field, and because of magnetic drag, this requires energy.

Fear of losing possessions?

What is a correct -phobia term for fear of losing possessions (assuming that one is NOT afraid forgetting, meaning it's not Athazagoraphobia). Bayerischermann 19:43, 30 July 2006 (UTC)

There's a list of phobias. Have you checked there?--Frenchman113 on wheels! 22:01, 30 July 2006 (UTC)

Yes. I also read a dictionary of phobias and can't find it. Anything else I can do to find the term? Bayerischermann 03:36, 4 August 2006 (UTC)

Help

The tornado section does not have the "three categories of tornadoes."

I am asked this by several people who dont know the awnser so I come here to Know the awnser and it is not here.

Please help!!!!! --Qho·^(talk)·_(contribs) 20:26, 30 July 2006 (UTC)

What three categories of tornados? I am not aware.

Do you mean shape? There is funnel (think triangle), wedge (think fat kind), and multi-vortex. If so, that's in the article.

Possibly there is some confusion with the Fujita scale or even the Saffir-Simpson Hurricane Scale? Melchoir 21:02, 30 July 2006 (UTC)