Wikipedia:Reference desk/Archives/Science/2008 July 12

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July 12[edit]

bee-wasp from Rockton, Illinois[edit]

one day i was working installing fences and i noticed a praying manits. it was the size of a male and it looked like a wasp. it had the body of a wasp up to the thorax and the arms neck and head of a praying mantis. ive been trying to find something online that looks like the one i saw and im starting to wonder if its a new species. let me know if you have any knowledge on this subject. thanks for taking the time to read this.

andrew Janesville, WI

—Preceding unsigned comment added by (talk) 01:46, 12 July 2008 (UTC)

I've removed your email to protect your account from spammers. --Bowlhover (talk) 04:40, 12 July 2008 (UTC)

It could have been a mantisfly. --Dr Dima (talk) 06:28, 12 July 2008 (UTC)

dopamine meaning in evolvement history[edit]

Is dopamine the only material to transmit "delight" feeling? Is dopamine only used for transmit this kind of feeling?

Then my main concern is, what is the meaning(from evolvement history point of view) of this kind of feeling? what's the advantage for animal with this kind of feeling? For amorism,then for reproduction(in fact I don't it the best way for breeding numerously, rapidly and widly)? Aaadump (talk) 02:52, 12 July 2008 (UTC)aaadump

I don't know if dopamine is the only chemical that does this—in fact I doubt it. But the evolutionary reason for having a neurotransmitter that makes the organism happy should be pretty clear; it's the basis for a good deal of learned behavior, just as having a neurotransmitter for pain and discomfort would be valuable. See, for example, operant conditioning, and try to imagine how impossible it would be for a creature to actively learn if it didn't experience some sort of positive feeling at times. -- (talk) 03:31, 12 July 2008 (UTC)
Dopamine isn't the only pleasure hormone; others include oxytocin and endorphins. Dopamine has a wide variety of functions other than transmitting positive feelings, as it plays a role in the cardiovascular system, regulating movement, learning, and information flow. See for more details.
As for the evolutionary benefits of pleasure hormones, oxytocin is produced during labour, breastfeeding, and sex. Endorphins are secreted after tiring activities and orgasms. The advantages of mitigating pain or rewarding the organism in these instances are pretty clear. --Bowlhover (talk) 04:37, 12 July 2008 (UTC)

chronic eye infection[edit]

Are there post consequences (sorry, I can't/don't remember the scientific term/word/name) of chronic eye infection(s) analogous (such as) chronic ear infections lead to deafness? (talk) 05:32, 12 July 2008 (UTC)

Chronic eye infections, especially trachoma, can lead to blindless. --Bowlhover (talk) 06:00, 12 July 2008 (UTC)
Several eye infections could lead to blindness. If you're worried about such consequences, you should consult a physician. — CycloneNimrod  Talk? 09:21, 12 July 2008 (UTC)
I think the word that you had in mind is "sequela". -- (talk) 13:39, 12 July 2008 (UTC)

Mechanism of phase boundary catalysis with 18-crown-6[edit]

Question asked on irc:

  • [13:50:21] <johndoe> well...Im trying to find out how 18-crown-6 acts as a phase transfer catalyst in a specific (not complicated) reaction...
  • [13:50:48] <johndoe> if there is someone out there who can help me,,,I'd be more than glad...
  • [13:51:16] <nsh> any more details?
  • [13:53:08] <johndoe> the reaction mixture contains methyl-3,5-dihydroxy benzoate, potassium carbonate, 18-crown-6 and acetone

Apparantly the chap has a presentation due, so rapid response would be greatly appreciated! (talk) 11:03, 12 July 2008 (UTC)

See crown ether - 18crown6 forms a complex with potassium specifically which solublises that cation in organic solvents, this will make the potassium carbonate more soluble in acetone. (talk) 11:32, 12 July 2008 (UTC)
This technical document from sigma aldrich should help (talk) 11:34, 12 July 2008 (UTC)

Is this an ant?[edit]

I am a bit confused by the description of this photograph [1]. The description claims that this photo shows ants and aphids, but I am not sure I see ants, or at least any species of ant I am familiar with. To me, I see aphids and something that looks like a beetle. Are those large black beetle-like things a type of ant?--Filll 14:45, 12. Jul. 2008 (CEST)

There may have been ants around, but possibly out of sight (cropped?). The view currently has in focus only aphid adults and nymphs. Shyamal (talk) 13:11, 12 July 2008 (UTC)
The description says, in German, "Aphids, who live symbiotically with ants" so I don't think it implies that there are ants in the picture. Fribbler (talk) 16:44, 12 July 2008 (UTC)

Tyre pressure[edit]

Is it true that the more a push bike's tyres are inflated, the less energy is required to propel the bike? If so why? -- SGBailey (talk) 13:23, 12 July 2008 (UTC)

Yes. Smaller area of contact with the ground, so less rolling resistance. Unless you massively overdo the inflation, I suppose, so that the tyres turn into huge balloons and the contact area increases again - but they would burst before that happened. --Heron (talk) 13:44, 12 July 2008 (UTC)
Not familiar with the term push bike, but searching through WP I found a picture of one. Doesn't look like you inflate the tires at all.
For a regular old mountain bike or road bike, yes, the more you pump up the tires the easier it will pedal, but you have to balance it against reduced traction. A lot of times mountain bikers will keep their tires highly inflated until they get to the trailhead and then let a little air out, especially if they'll be descending. However running at too low a pressure is a good way to ruin your sidewall, as I found out (I didn't use to like to run high pressures because I got too many holes in my tubes that way). --Trovatore (talk) 16:46, 12 July 2008 (UTC)
If you just say "bike" the question of motor bike or push bike may be raised, hence the use of a distinguishing word. Your picture doesn't look like a push bike, but is instead a velocipede. -- SGBailey (talk) 21:04, 12 July 2008 (UTC)
Ah, so that would be one of those unnecessary back-formations where you disambiguate what's already the unmarked form. Along the lines of snow skiing or ice hockey or American football. --Trovatore (talk) 22:16, 12 July 2008 (UTC)
I'm not sure I understand what you are saying. In the UK at least there are bicycles and motorbikes. If you say bike, it is ambiguous; you either need to disambiguate or you need context. "Snow skiing" isn't a phrase I'm aware of. "Ice hockey" is similar in a way to "Field hockey" but is played on ice and the two games need to be distinguishable. I would imagine - though I don't know - that field hockey came first. "American football" obviously needs the disambiguation that it has since the game is completely different to "football" in the rest of the world - to disambiguate the other way one uses "soccer", but soccer is more of a nickname than the real name "football". I have no idea which came first, soccer or American football. Australian rules football is yet another different game needing its disambiguation. -- SGBailey (talk) 23:58, 12 July 2008 (UTC)
In the US we would call a "bike" a "bicycle" if we needed to distinguish it from a "motorcycle". The term "push bike" sounds weird to us, like a bike that doesn't work properly, so you must get off and push it home. StuRat (talk) 17:40, 13 July 2008 (UTC)
This is getting rather off-topic, but roughly speaking, the modern forms of football (association, rugby, aussie rules, American, etc.) arose from the process of codifying and formalizing the original proto-football in the mid 19th century. There was previously a lot of variation in how football was played (such matters as whether or not you were allowed to pick up the ball) and this is reflected in the range of rulesets produced. Algebraist 00:22, 13 July 2008 (UTC)
See more about this in Football (which is semi-protected to stop edit wars and vandalism between fans of different sports called "football"). PrimeHunter (talk) 00:35, 13 July 2008 (UTC)
In the UK it's still common to call a bicycle a push bike. The ideal tyre pressure (and energy required) will also depend on the width of your tyres. There is a very good article about this sort of stuff here.--Shantavira|feed me 17:45, 12 July 2008 (UTC)
You looked so pretty/as you were riding alo-o-o-ong... (talk) 04:00, 13 July 2008 (UTC)
anyway... another reason for the inflation thing (true for cars as well, etc., of course) the sidewall of the tire is not a perfect spring, in fact when flexing it and returning, a lot of energy is lost as heat. as the tire turns, the sidewall is continually flexing as it reaches the contact point with the road, and unflexing as it leaves it. the higher the pressure, the less the flexing, and the less energy turns into heat. a byproduct of that is that sustained rolling around on low pressure causes the sidewalls to weaken, but that's more of a car problem than a bike problem. Gzuckier (talk) 19:40, 14 July 2008 (UTC)

ohm resistance[edit]

what is the ohm resistance of fingernail bed. if someone had bitten fingernails and touched live and neutral would electric shock scenario differ to intact skin. fossygirl —Preceding unsigned comment added by Fossygirl (talkcontribs) 13:47, 12 July 2008 (UTC)

Yes, it would be more dangerous for someone with bitten fingernails to touch a live wire, especially so if the finger was still damp from being bitten. Dry nail has a very high resistance, and dry skin can also have a resistance of several million ohms under certain conditions, but damp skin, especially if salty, can have a resistance of only several thousand ohms, resulting in a fatal current from mains voltages. Dbfirs 18:12, 12 July 2008 (UTC)


how to make telescope at home for stargazing

See Amateur telescope making and the external links there. PrimeHunter (talk) 16:19, 12 July 2008 (UTC)

habits of cobras of Thailand[edit]

Where and when do cobras in Thailand sleep? —Preceding unsigned comment added by Pwjaffe (talkcontribs) 16:38, 12 July 2008 (UTC)

Why Thailand? Seems extremely specific and not that relevant. It may help if you specific what species of cobra your referring to, e.g. Naja kaouthia, King Cobra since it likely varies. Also what sort of location? A cobra living deep in the jungle may have somewhat different behaviour to one living near an urban centre Nil Einne (talk) 19:32, 12 July 2008 (UTC)

Where does the black and white apitting cobra sleep and when does is it up and hunting? Why Thailand? Becasue it killed one of my dogs and the dogs killed one of them. —Preceding unsigned comment added by Pwjaffe (talkcontribs) 19:59, 12 July 2008 (UTC)


What is the name of the paper in which Edward Drinker Cope described the species Miacis parvivorus? Leptictidium (mt) 17:43, 12 July 2008 (UTC)

This paper references it as "Cope, E.D. 1872. Third account of new Vertebrata from the Bridger Eocene ofthe Wyoming Territory. Proceedings of the American Philosophical Society 12: 469–472." --Bowlhover (talk) 18:48, 12 July 2008 (UTC)
Thank you. Leptictidium (mt) 19:21, 12 July 2008 (UTC)

Shaolin Monks[edit]

A few days ago I went to a show organised by the shaolin monks. Well I would like to have the scientific rundown on their performances, for some reason "I can extract chi outside of my body and obtain temporary invulnerability", doesn't satisfy me. Bastard Soap (talk) 18:27, 12 July 2008 (UTC)

See if Autosuggestion has anything relevant, that's probably what they're doing. --Tango (talk) 19:40, 12 July 2008 (UTC)

Yes, that's definitely part of it. But what about the trick were they place a spear at their throat and push with all their strength? How do you condition cartilage to withstand such a thing?Bastard Soap (talk) 19:53, 12 July 2008 (UTC)

Without having seen the trick in question, I can't be sure about this, but I would bet that -- typically for a demonstration like this -- the spear has a flexible shaft made of bamboo or some comparable material, not a completely rigid one made of some tougher substance. A flexible shaft is a lot less dangerous than a rigid one, for obvious reasons; when you push, it bends. Also, how do you know that they are pushing with all their strength? Because it looks like they do?
In any case, as it happens, the cartilage there is pretty tough stuff even without any kind of conditioning, which makes it handy for tricks like this. An episode of Penn & Teller's Bullshit! deals with this, and in fact, you can check it out on the internet. They do the trick with arrows there, but the principle is the same. They discuss it almost exactly halfway through the episode. The crappy player there unfortunately doesn't include a counter, so I can't tell you exactly where, but check it out.
I'm not putting the Shaolin guys down, mind you. They're really good at what they do; pretty awesome performers... But supernatural they ain't. -- Captain Disdain (talk) 20:24, 12 July 2008 (UTC)

Definitely not supernatural, the grand master slipped durring a performance :P (talk) 20:31, 12 July 2008 (UTC)

One of the performances consisted of sustaining a man on 5 spears, or on just one spear. An other one consisted of extreeme twistings of their bodies. Doesn't too much stretching weaken the body?Bastard Soap (talk) 21:10, 12 July 2008 (UTC)

Sustaining a man on five spears is no big deal, really -- that's just weight distribution. If you've got a guy who weighs something like 70kg, that'd be just around 14kg of weight per spear. (A similar classic trick is to have a bunch of friends lift you using just their forefingers -- it looks crazy, but it's all about weight distribution. In the example here you can see that when the guys one one side stop lifting, the guys on the other side are suddenly in trouble.) A single spear is a better trick, but there are undoubtedly ways of doing it. I can't offer insight into it without seeing what they do, but there are many ways of doing tricks like this. (I should probably stress that it's not cheating as such; it's just that the trick isn't as difficult or insane as we think.)
As for the stretching, contortion is an old form of entertainment. It's not at all dangerous as such, though if you don't know what you're doing, I'm sure you can hurt yourself. If you do know what you're doing (i.e., have trained yourself properly, which isn't gonna happen overnight) and happen to have been born with a body that's well-suited for it, you can do pretty fantastic tricks -- it's no surprise that it's a useful skill for magicians. A cool example of this skill this can be found here. -- Captain Disdain (talk) 21:42, 12 July 2008 (UTC)
I should probably add that there's a strong tendency for people to believe that there must be some kind of a supernatural (or at least extremely complex) explanation for feats like this, because they seem so amazing. A good example can be found in thesome of the comments of another YouTube video, where people swear up and down that they are "channeling energy upwards" or focusing their energies or whatnot. In a way, it's willful stupidity in that we really convince ourselves that the weight we are lifting must be heavier than it really is. In a large part, that willingness to believe is what the illusions performed by magicians -- and, unfortunately, many cons -- are based on. (That said, many famous magicians, such as Harry Houdini, James Randi and Penn and Teller have dedicated much of their lives to educating people about these things. They don't pretend to have supernatural powers, they pretty much tell you up front that they will now show you an amazing illusion; essentially, they tell you that they're going to lie to you, and then they do so. Penn and Teller in particular have made it a trademark of theirs to show you exactly how they fool you into thinking you're seeing something magical and explaining how they do it, and then doing something even more amazing that leaves you wondering how the hell they just pulled that off.) -- Captain Disdain (talk) 21:57, 12 July 2008 (UTC)
people with ehlers-danlos syndrome have weak connective tissue and can be extremely flexible, controtionists, escape artists, etc. Gzuckier (talk) 19:36, 14 July 2008 (UTC)


what's BDA..why it need steroid for medicine?

Google does mention any diseases called BDA ([2]), do you have any context for the abbreviation? --Tango (talk) 19:42, 12 July 2008 (UTC)
Are you asking about Beclometasone dipropionate (aerosol)? From the article, this appears to be a steroid that is sometimes used in inhalers. -- KathrynLybarger (talk) 19:47, 12 July 2008 (UTC)

fractionating column[edit]

What is a 3 phase fractionating colunm?

Tade —Preceding unsigned comment added by (talk) 20:35, 12 July 2008 (UTC)

See Fractional_distillation#Design_of_industrial_distillation_columnsCycloneNimrod  Talk? 20:43, 12 July 2008 (UTC)
Actually, that might not exactly answer your question. Apologies if it doesn't. — CycloneNimrod  Talk? 20:45, 12 July 2008 (UTC)
Possibly it refers to a Steam distillation column - the three phases would be
1. vapour
2. water
3. condensed liquid to be steam distilled
or maybe it means something else? (talk) 21:05, 12 July 2008 (UTC)
Phases are different states of the same matter. A three-phase column could be doing mass transfer between solid, liquid and gas phases; or there could be different constituent phases, such as two different liquid phases and a gas phase.
What is the context? I know the experts on fractionation columns personally, I can find the answer if you give me a little more. (Also, a coker-fractionator might qualify as a three-phase column - heavy crude solidifies into petroleum coke while producing a liquid and gas fraction). Franamax (talk) 03:20, 13 July 2008 (UTC)