Wikipedia:Reference desk/Archives/Science/2009 July 10

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July 10

SAT identification

Yesterday (July 8) at around 11:17 local time I saw two satellites, separated by about a degree, pass by Cassiopeia. They were initially both of magnitude 2-3, but dimmed as they climbed higher into the sky. Does anyone know what these satellites are, and why they have nearly the same orbit? I live in Toronto. Before you suggest one of the them was the ISS and the other was a spacecraft trying to dock with it, that can't be it because I saw the ISS pass by several minutes later. Interestingly, a search on Heavens Above turned up nothing. --Bowlhover (talk) 00:11, 10 July 2009 (UTC)

It seems likely one of them was Cosmos 1602, it went through Cassiopeia at about that time [1]. I don't have any ideas about the other. anonymous6494 16:29, 10 July 2009 (UTC)

Amytriptyline

Is this the kind of drug for which users develop a tolerance, requiring higher doses to achieve the desired effect? If so, does the fatal dose also increase as tolerance goes up?

This is not a request for medical advice, this is part of my research in writing a work of fiction based on the life of Nick Drake, who died from an overdose of this drug. -GTBacchus^(talk) 01:22, 10 July 2009 (UTC)

In short, yes. In this study, tolerance to the effects of amitriptyline built up differentially over measures of sedation, psychomotor function and memory. See also [2]. - Nunh-huh 02:50, 10 July 2009 (UTC)

The word "tolerance" may be a bit misleading when it comes to antidepressants. A great deal of research shows that it usually takes a couple of weeks before the mood-altering effect kicks in; however other effects such as sleep alterations kick in immediately. This is often taken to mean that some sort of tolerance-like effect in the brain plays an essential role in the function of the drug. It's generally not the case, as I understand it, that people taking antidepressants need to take steadily increasing doses to get a constant result. Looie496 (talk) 03:16, 10 July 2009 (UTC)

Thank you both. That's very helpful. -GTBacchus^(talk) 03:19, 10 July 2009 (UTC)

OR Speaking as a long-term amitriptyline user, it's not the case that I have had to increase the dosage over the years to get the same effect, so no tolerance has been developed. However, I'm now trying to stop taking it and am having to slowly decrease the dose to nothing: so far it's taken 3 months and I'm on course to be off it in another month's time. This is because of the physical side-effects of stopping taking the drug, which include the possibility of heart arrhythmia (or so I understand). You could say I'm addicted to it, under some definitions of addiction. --TammyMoet (talk) 08:51, 10 July 2009 (UTC)(Edit) The only tolerance I had to build up was tolerance of the effects of the drug, in other words, adjusting to the change in sleep patterns the drug brought.--TammyMoet (talk) 08:53, 10 July 2009 (UTC)

Coriolis force

Suppose a mass m is moving radially from the centre of a moving carousel. There has to be a tangential force in order to keep it moving in a straight line, and my question is what is this force. One way I would do it is to find the angular momentum, differentiate it to find torque, and divide by r to get the force. This gives me 2mw*v_rad. Doing something similar with momentum though, I get half that value (p=mwr, F = dp/dt = mw*v_rad). What did I do wrong? —Preceding unsigned comment added by 70.82.247.24 (talk) 03:23, 10 July 2009 (UTC)

Momentum and velocity are both vectors. So

${\boldsymbol {p}}=m{\boldsymbol {v}}=m(v_{r}{\boldsymbol {e}}_{r}+r\omega {\boldsymbol {e}}_{\theta })$

where $v_{r}{\boldsymbol {e}}_{r}$ is the particle's radial velocity and $r\omega {\boldsymbol {e}}_{\theta }$ is its tangential velocity. So

${\boldsymbol {F}}={\dot {\boldsymbol {p}}}=m{\dot {\boldsymbol {v}}}=m(v_{r}{\dot {\boldsymbol {e}}}_{r}+v_{r}\omega {\boldsymbol {e}}_{\theta }+r\omega {\dot {\boldsymbol {e}}}_{\theta })$

where I have assumed that v_r and ω are constant. Now

${\dot {\boldsymbol {e}}}_{r}=\omega {\boldsymbol {e}}_{\theta }$

${\dot {\boldsymbol {e}}}_{\theta }=-\omega {\boldsymbol {e}}_{r}$

so

${\boldsymbol {F}}=m(v_{r}\omega {\boldsymbol {e}}_{\theta }+v_{r}\omega {\boldsymbol {e}}_{\theta }-r{\omega }^{2}{\boldsymbol {e}}_{r})=2mv_{r}\omega {\boldsymbol {e}}_{\theta }-mr{\omega }^{2}{\boldsymbol {e}}_{r}$

The first term is the Coriolis force; the second term is the centripetal force. Gandalf61 (talk) 11:54, 10 July 2009 (UTC)

dino to bird query

This page http://creation.com/bird-breathing-anatomy-breaks-dino-to-bird-dogma challenges the dino evolving into birds theory. I am wondering about the accuracy of the science behind the author's arguements. Please: no creationism vs. evolution debates. —Preceding unsigned comment added by 216.154.22.92 (talk) 04:09, 10 July 2009 (UTC)

It's the same tired arguement that has been going around for years and years. The basic principle is that of "intermediate forms". In order to say that Animal X evolved into Animal Y, there needs to be a "smooth transition" between the two; new structures or forms don't just spring out of no where, the change gradually over time. That's a cornerstone of evolution. So, the creationist side of the debate (which is what creation.com is all about, n'est ce pas?) finds some evolutionary gap in the fossil record, and hammers it home as PROOF that evolution does not happen. First it was the flagellum in single-celled organisms, then it was the eye, now it appears they have latched on to bird lungs. The deal is, finding a SINGLE example which has not yet been adequately explained does not in any way invalidate the entire system.

Look at it this way: Imagine a brick road, with billions of bricks, stretching from Los Angeles to New York. Now, imagine that there are some bricks missing. Like, once every ten or twenty miles, there's a missing brick. Now, imagine saying "I cannot get from LA to New York because there's a brick on this road that is missing. It is impossible to drive that long distance given that the road is not complete." That is exactly what this guy is saying. There are literally millions of pieces of evidence, which DO neatly connect the extinct forms to modern forms via evolution. The deal is, that sometimes there's a bit, like these bird lungs, which has not been discovered yet, or adequately explained yet. Just like the flagellum before it, someone will eventually come along to connect the dots. --Jayron32.talk.contribs 04:19, 10 July 2009 (UTC)

Ignoring the creationist aspect, all reputable paleontologists believe that birds evolved from some type of reptile, but there is a small minority, including the ones interviewed for that program, who think that the reptiles in question were not dinosaurs. Most paleontologists feel that the dinosaur origin is supported beyond reasonable doubt by the existing evidence. Looie496 (talk) 04:43, 10 July 2009 (UTC)

Possibly a better analogy: In the Sahara a dune shifts, revealing a piece of Roman road. Over time more such pieces are revealed, near the line between Carthage and, let's say, Old Ghana. Scoffers object to the inference that there was a continuous road .... But the analogy is flawed, in that road-building is teleological (so we know that continuous roads between inhabited places are more likely than random patches of road) and evolution isn't. —Tamfang (talk) 17:42, 21 July 2009 (UTC)

It you're going to ask a question based on an overtly creationist website report - on a reference desk that's dedicated to giving proper, scientific answers - you cannot reasonably demand that no creationism-versus-evolution discussion will be required. As Jayron32 so eloquently points out - the absence of one tiny step in the path doesn't destroy the argument that birds evolved from dinosaurs. Absences are only to be expected in a science where we mostly rely on chance findings of bazillion year old animals that were frozen in carbonite or something - mostly out in the middle of a few hundred miles of rocky desert in outer mongolia. For there to be a solid consensus that birds did NOT in fact evolve from dinosaurs, there would have to be a piece of contradictory proof that they evolved from something else. Efforts to use these small gaps to somehow "prove" that evolution isn't true are simply not going to convince the vast majority of people in the world. Frankly, the more interesting questions are:

• Did birds evolve directly from Dinosaurs? If so, which family?
• Did birds and dinosaurs evolve independently from a common ancestor? If so, which ancestor?
• Did dinosaurs evolve from birds? (This is a radical viewpoint that is probably pretty much disproved now - but was around when it was first speculated that birds are descended from dinosaurs...the theories were called "Birds are dinosaurs" and "Dinosaurs are birds" - and proponents of the latter liked to use the initial letters to indicate that Birds Are Dinosaurs is a "BAD theory").

"None of the above" does not seem to be a viable theory.

SteveBaker (talk) 14:49, 10 July 2009 (UTC)

These god in the gaps clowns are shooting themselves in the foot when they claim that a missing link disproves evolution, because every time scientists find one, they have to retreat to an even narrower intellectual precipice. --Sean 13:52, 13 July 2009 (UTC)

Every time you find a Missing Link, you create two gaps where there had been only one! —Tamfang (talk) 17:30, 21 July 2009 (UTC)

cauterize instead of suture

can you cauterize instead of suture —Preceding unsigned comment added by 74.65.3.30 (talk) 05:54, 10 July 2009 (UTC)

If you're really tough, and I mean Rambo tough, sure you can, but don't take that as medical advice. Just advice from someone who's been places and seen things (or been at home and seen some bad movies). See cauterization. Incidentally, these two consecutive questions, coming from the same poster and taken together, paint a very frightening picture. See a doctor, they won't judge you.--Rallette (talk) 06:56, 10 July 2009 (UTC)

Since silver nitrate is a cauterizing agent, and was historically used to treat gonorrhea, I’m thinking the connection between the two questions is that the poster’s been doing some reading about silver nitrate, not that the poster is contemplating doing surgery on himself. Red Act (talk) 07:20, 10 July 2009 (UTC)

Damn, and I was so enjoying imagining him treating his ear gonnorrhea by cauterizing it. ~ mazca ^talk 08:04, 10 July 2009 (UTC)

It really depends on the context. One of the big differences between cauterization and suturing is what ultimately happens to the patient's SKIN. A cauterized wound will form scar tissue, which shrinks and tightens around the area. If this is a large area, it will likely be extremely uncomfortable and may even require a graft. Cauterization is generally prefered for smaller jobs. Suturing, on the other hand, brings existing regions of skin together, so the resulting scar tissue is much less. Of course, there needs to be skin available for this to even be an option. There are other factors involved, this is just one consideration. It really depends what the injury is you're talking about. --Shaggorama (talk) 14:23, 10 July 2009 (UTC)

the clap

how did they treat the clap before antibiotics —Preceding unsigned comment added by 74.65.3.30 (talk) 05:58, 10 July 2009 (UTC)

Historically, silver nitrate was used, and according to some, mercury. See Gonorrhea#Historically. Red Act (talk) 06:19, 10 July 2009 (UTC)

I thought that mercury (in the form of calomel) was used to treat syphilis, not gonorrhea... 76.21.37.87 (talk) 09:00, 10 July 2009 (UTC)

Besides syphilis and gonorrhea, mercury was used to treat ailments as diverse as depression, tuberculosis, toothaches, and constipation.[3] There were essentially no legal restrictions on claims of medical effectiveness back then, so a lot of drugs were touted as curing practically everything. Red Act (talk) 09:37, 10 July 2009 (UTC)

"A night in the arms of Venus leads to a lifetime with Mercury." Matt Deres (talk) 17:25, 11 July 2009 (UTC)

Ear infection

how did they treat Ear infection before antibiotics —Preceding unsigned comment added by 74.65.3.30 (talk) 07:16, 10 July 2009 (UTC)

Are you aware of our "search" function, over on the left there? You could type things like ear infection and click Go, and you'll get a whole article on it. I did so just now, and found that in the page regarding middle ear infections, it sounds like they had to wait until it got severe and then performed a myringotomy. Tempshill (talk) 07:21, 10 July 2009 (UTC)

Uh, yeah, silver nitrate is an antiseptic, so they presumably sometimes used it to treat otitis externa, too. Red Act (talk) 07:33, 10 July 2009 (UTC)

Just in case you’ve been reading some stuff about the medical wonders of silver, note that while all sorts of claims are being made about the use of colloidal silver as an alternative medical treatment, there are no evidence-based medical uses for ingested colloidal silver. Furthermore, excessive consumption of colloidal silver can make your skin turn bluish-gray, and may hamper the effectiveness of some drugs which actually do work, such as tetracycline. Red Act (talk) 08:09, 10 July 2009 (UTC)

There are various folk remedies for earache, one of which involves baking an onion until soft, then removing the core and inserting it into the affected ear. The heat will disperse the gunge, while onions are known to have antiseptic properties. --TammyMoet (talk) 08:46, 10 July 2009 (UTC)

I've recently read that the outcome for ear infections with or without antibiotics treatment does not differ significantly. You can treat them with anti-inflammatory drugs, like Aspirin, and there are any number of folk remedies involving onions and potatoes. --Stephan Schulz (talk) 09:08, 10 July 2009 (UTC)

In recent years there have been a number of studies showing that "watchful waiting" is a reasonable course of action in uncomplicated acute otitis media in a healthy child. See this [4] for an example. There are many others. Of course, there are rare complications in which the ear infection proceeds to cause mastoiditis or meningitis. So, one needs to weigh the costs and benefits of the treatment. It is argued that since most cases of acute otitis media will resolve on their own (that's what the immune system is for, after all) and since antibiotic therapy is associated with increased antibiotic resistance among the organisms we are trying to treat, we should not immediately give antibiotics every time a child gets an ear infection. Even without immediate antibiotic therapy, the child needs to be re-evaluated within 48 hours or so to make sure that the infection isn't getting worse. Of course, the management decision is a very complicated equation -- how sick is the child? how old is the child? how reliable are the parents? how good will be the follow-up? These are questions the doctor should be asking every time he/she decides whether or not to prescribe antibiotics. And as always, the question continues to be debated. But this is certainly not "dubious". --- Medical geneticist (talk) 11:52, 10 July 2009 (UTC)

Thanks for the ref. I put in the templates as a mild joke and a reminder that stuff someone recalled from somewhere is not always the best source - even if someone is me ;-) --Stephan Schulz (talk) 12:17, 10 July 2009 (UTC)

Onion juice dripped into the ear is still used for persistent ear infections. It works as an Anti-inflammatory the compound identified was Quercetin. Onion contains thiosulphinate (no page?!) that works as an antibacterial and antifungal agent [5]. Thyme has Antiseptic properties. So, no they didn't have to wait, some herbal remedies actually are effective without employing products of the pharmaceutical industry (who are quite good at extracting some substances and selling their products at a price several orders of magnitude higher than the origin).71.236.26.74 (talk) 09:57, 10 July 2009 (UTC)

I assume you are looking for thiosulfate. --Jayron32.talk.contribs 12:28, 10 July 2009 (UTC)

Thought so at first, but there seems to be some difference. Maybe you could check this [6] and see what it's about.71.236.26.74 (talk) 15:11, 10 July 2009 (UTC)

This page shows the structures for both thiosulfate and thiosulfinate. Note that thiosulfate is a specific compound, and the thiosulfinates are a whole class of compounds. Red Act (talk) 15:33, 10 July 2009 (UTC)

Taking this question with the preceding one, wonder if someone's been having unprotected aural sex? DMacks (talk) 16:43, 10 July 2009 (UTC)

Pardon? 87.81.230.195 (talk) 22:28, 10 July 2009 (UTC)

The clap + ear infection = what HAVE you been putting in your EAR? --Jayron32.talk.contribs 22:39, 10 July 2009 (UTC)

Brain Freeze

Hello, my name is corey. I had a question about your definition of a Brain freeze. Now, while i admit your explaination is correct, i also wondered this- would not the "Brain Freeze" in fact be your brain overheating? Because i read an article in a magazine some years back that stated your heart and body forces too much blood to your head which in fact causes it to overheat. The explaination you have refers to the pain suffered from your constricting arteries in the roof of your mouth, but it confuses me. If i wrap something around my arm tightly for ten to twenty seconds, the veins and arteries swell. When i remove it, there is very little pain that comes. If the pain associated with brain freeze comes with shrinking blood vessels why is there no pain when they are swollen? Also, during a brain freeze, one can place theyre hands on the sides of thier neck to relieve the pain- how could this be if the pain is directly stemming from the roof of your mouth?

Sorry, i guess i kinda asked several questions there.

Basically my question i was wondering about is this-

During a brain freeze, does your body push more blood to the area to compensate, thereby causing brain overheating, or is the pain only caused by your blood vessels regrowing to normal size? —Preceding unsigned comment added by 75.164.152.179 (talk) 08:32, 10 July 2009 (UTC)

In no way am I an expert, but while you wait for a better response, here is my best attempt at answering the question:

There are 2 main theories on the origin of pain, one theory holds that the pain is simply caused by the rapid dilation of the blood vessels of the palate and pain is transferred to the brain via the trigeminal nerve. While the other theory states that the body overreacts to this cold stimulus and pushes more blood to the brain trying to heat it. This alters the follow of the blood in the brain and causes this familiar brief headache. Personally, I am more inclined to believe the latter theory.

Cheers!

Λuα ^{(Operibus anteire)} 10:49, 10 July 2009 (UTC)

I thought blood vessels contracted in the cold, so wouldn't it be rapid contraction, not rapid dilation of blood vessels? Regards, --—Cyclonenim | Chat  18:03, 10 July 2009 (UTC)

True, but the pain is not usually attributed to vasoconstriction, but to the rapid dilation that follows.

Actually, this question is quite interesting and one which can be to a certain point investigated at home. If the first theory is right, then keeping the cold substance in contact with the roof of the mouth shouldn't cause a brain freeze. On the other hand, if a brain freeze is experienced with the cold substance still in contact, then the second theory is right. In either case, the cold material used should not be allowed to reach body temperature or the results will be invalid.

This is in no way encouraging anyone to try this at home. Don't sue me should permanent damage happen.

Do not try this at home...No, really, don't!

Cheers!

Λuα ^{(Operibus anteire)} 20:01, 10 July 2009 (UTC)

Tried it with an ice lolly, got brain freeze whilst still in contact with the ice. Regards, --—Cyclonenim | Chat  20:29, 10 July 2009 (UTC)

You know, im inclined to believe both theories. Ive tested both, and they both seem to have substance. I still don't quite understand it- if both instances are right, do we include both theories in our definition of "Brain Freeze" here on wiki, or do we just shrug off my suggestion that i first posted as merely a possible theory and not a literal possibility? sorry- i'm too inquisitive for my own good :p

For those wondering, i just registered here a few days ago, and im the one who posted this question in the first place. —Preceding unsigned comment added by Blaze113 (talk • contribs) 09:07, 11 July 2009 (UTC)

Unfortunately it constitutes original research if we just stick it in an article here. We need to find a reliable source before we can put it in. Regards, --—Cyclonenim | Chat  09:46, 11 July 2009 (UTC)

Ah, very true. Forgot that little bit there... oh well. I'll keep hunting and researching, see what others have to say about it. If anyone gets more info, please, feel free to place it in here. —Preceding unsigned comment added by Blaze113 (talk • contribs) 09:55, 11 July 2009 (UTC)

Both mechanisms could be at work, but until someone proves it conclusively, we will never know.

Not that big of a deal though.

Cheers!

Λuα ^{(Operibus anteire)} 13:07, 11 July 2009 (UTC)

Zigzag pattern on railway tracks

I was in Newcastle railway station this weekend. Sitting waiting for my train to leave, I noticed the tracks on the adjacent line showed an unusual zigzag pattern. I took a photo (it's rather poor mobile-phone quality) which is here. Can anyone explain what these patterns are?

My thoughts are:

1. it's an artifact of manufacturing, but the tracks really don't look new
2. it's an artifact of some rail-surface reconditioning machine, but why would it leave this pattern
3. it's been added to enhance friction (to help trains brake), but why this pattern?
4. it's caused by the action of train wheels - but it seems much too regular and well defined, and this is a terminal platform where trains are moving slowly and braking very gently

Because I noticed it only once I'd sat in my train, I don't know if other tracks have this pattern, or if this pattern is visible for more than the 20ft or so section I could see. I can't see anything relevant in the rail tracks or the like. 87.113.26.43 (talk) 11:30, 10 July 2009 (UTC)

I should note, incidentally, that I don't think the pattern is sinusoidal, I really think it is triangle wave with rounded corners. A sinusoidal form might suggest some kind of cleaning or reconditioning machine which moves a helical element down the track, but this doesn't look to be the case for this track. 87.113.26.43 (talk) 11:35, 10 July 2009 (UTC)

The irregularity of the marking pattern suggests that it has been applied manually. My first guess is that it was drawn by a maintenance worker to identify rail(s) due for replacement or realignment. My second guess is that it marks a stopping point for train drivers to see. Cuddlyable3 (talk) 11:59, 10 July 2009 (UTC)

I was going to say that I thought it was too regular to be manually applied (at a large scale); at a smaller scale I'd say it had been applied by an angle grinder or some machine with similar function, which makes for a rather rough line. Clever though it is, I don't think your "stopping point" theory is correct - for terminal lines the buffers should be sufficient for that, and for through lines (which this isn't) there are signs which mean "if you're a six car train, stop here". 87.113.26.43 (talk) 12:08, 10 July 2009 (UTC)

Speaking of stopping, might this be a pattern that facilitates stopping the train if the rails are covered in ice or snow? I seem to recall that last winter British Rail had some stopped services because of ice and snow.71.236.26.74 (talk) 12:35, 10 July 2009 (UTC)

This section is well inside the canopy of the station, at least 100m from anywhere snow could land. Ice could form, but only from condensation (so not much). It's my understanding that snow-and-ice affects british railways mostly due to points getting frozen. 87.113.26.43 (talk) 12:43, 10 July 2009 (UTC)

Is that actually etched into the track? In the photo, it looks like chalk markings. They mark tracks to be repaired with chalk here (U.S.). My son loves railroads and we got to walk along the tracks recently when the local railroad was being marked for repairs. -- kainaw™ 12:49, 10 July 2009 (UTC)

To me that looks deliberately applied for some reason. I can't think of any reason. Maybe the local kids having input to their surroundings? It also might be a reflection of the overhead structure, having no material presence on the tracks at all. Bus stop (talk) 12:51, 10 July 2009 (UTC)

It's a rubbish photo: yes, it's definitely etched into the track somehow (I'd say with some kind of grinding tool or wire brush deivce), but only to a very shallow degree (maybe "polished" would be more accurate than "etched"), which is why I don't think it'd be of much help for traction. If it was marking, as you and Cuddlyable3 have suggested, it seems unlikely they'd go to such trouble (surely a chalk mark on the side of the rail would do), and surely track is replaced by removing and replacing a whole length, rather than just a bad section. of a given length. I'm confident it does have some utilitarian purpose, as Network Rail certainly aren't given to fripperies like decorative rail etching. 87.113.26.43 (talk) 12:58, 10 July 2009 (UTC)

It might be put in at the factory as a wear marker - either to indicate that the rails have worn out or that they've been broken (?) in (more likely, given the shallowness of the markings). --Stephan Schulz (talk) 13:08, 10 July 2009 (UTC)

My mistake -- it really does exist. (Enlarge photo to see it better.) I also found this picture which might shed some light on it. This could also possibly explain how those marks got there. Bus stop (talk) 13:11, 10 July 2009 (UTC)

Thanks, I'm very impressed that you found such a clear photo. Note that the track in Bus stop's photo is a through-platform, carrying intercity traffic, rather than a terminal backwater platform. 87.113.26.43 (talk) 13:45, 10 July 2009 (UTC)

Could it serve a similiar purpose as a rumble strip? Livewireo (talk) 14:08, 10 July 2009 (UTC)

They're rumble strip welds, used improve electrical contact between rail and wheel (for track management, not power). See [7] Paragraph 17. Bazza (talk) 14:34, 10 July 2009 (UTC)

Fantastic, well done and thanks a lot; the photos in that report look exactly like those in the station. This is just the kind of thing that there should be a wikipedia article about; but I can't seem to find any further information under that name (perhaps they're also called something else). 87.113.26.43 (talk) 15:29, 10 July 2009 (UTC)

It is done by grinding, it is done intentionally [8] and the book one can not access here [9] says that it's done to avoid exchanging rails which have a rolling contact surface that is still o.k. 71.236.26.74 (talk) 15:06, 10 July 2009 (UTC)

No - the marks in the OP's photo are not done by grinding. They have been welded on, as I explained above. Bazza (talk) 15:23, 10 July 2009 (UTC)

Your post came in while I was digging up references and my ISP offers "high speed" by cashing pages and only reloading once in a blue moon. The wikipedia software then sorted the timeline correctly, but made it look as though I was contradicting you. No such intent, your source looks like that's what OP encountered. 71.236.26.74 (talk) 15:04, 13 July 2009 (UTC)

Wow -- that is it. It is used on stretches of track that do not receive sufficient or fast enough traffic to keep the surfaces clean of oxidation or other detritus. This is to increase electrical conductivity between the wheels and the track, and this in turn is to enable detection of the train in its "berth" in the station. Bus stop (talk) 15:33, 10 July 2009 (UTC)

This is mentioned at Track_circuit#Railhead_contamination, if someone can supply a picture that would no doubt be a good addition.83.100.250.79 (talk) 15:56, 12 July 2009 (UTC)

distance between plants

From a guide I got that to plant carrots you need a distance between 25 and 30 cm. What would happen if the distance is greater than 30 cm? I suppose that a shorter distance means that the planst will compete with each other, but what speaks against the other case?--Quest09 (talk) 15:47, 10 July 2009 (UTC)

If you plant your carrots further apart than necessary, than you get less carrots than you could be getting. I expect (but do not know) that that's all there is to it. Algebraist 15:50, 10 July 2009 (UTC)

Plant distances given are a minimum. If you want to plant your carrots 500' apart, it will not bother the carrots, but will make for a lot more time spent walking between your carrot plants then a shorter distance. Googlemeister (talk) 15:56, 10 July 2009 (UTC)

It is assumed that maximum carrot per unit of growing soil is the aim of all farmers. Bus stop (talk) 16:04, 10 July 2009 (UTC)

I assume you are talking about the spacing between rows of carrots. The spacing between plants is only a couple of inches (few centimeters). Rmhermen (talk) 01:57, 11 July 2009 (UTC)

Why is the temporal bone classified as irregular?

Hi everyone I noticed that most of the bones that encase the human brain such as the parietal, frontal and occiptal bones are all classified as flat bones whereas the temporal bone is not. I've had a look at the article on the temporal bone but it doesn't say why it is classified as an irregular bone whist the other bones that make up the skull are flat bones. Can anyone offer me an explanation or point me in the direction of some info? Cheers RichYPE (talk) 16:26, 10 July 2009 (UTC)

Have you read irregular bone? It gives a definition of what is required for a bone to be classed as irregular. Regards, --—Cyclonenim | Chat  17:14, 10 July 2009 (UTC)

Smoking tea or coffee

Would smoking tea or coffee get the caffeine from these products into your bloodstream efficiently enough to be comparable to drinking it? I would think that it would be a quicker way, but I am not sure if the caffeine actually makes it through the burning process or converts into something else. —Preceding unsigned comment added by Frogmaster3950 (talk • contribs) 16:27, 10 July 2009 (UTC)

Coffee grounds do not burn readily, so you would have to mix them with large quantities of additives. Tobacco is usually soaked in a little butane to help it light; these additives are major contributors to the "unhealthy side effects". The amount of extra additive needed to burn coffee grounds would probably result in an extremely unhealthy concoction. As far as smoking tea, it can be done, but it is generally not regarded as a pleasant aroma (and this is considering that it is compared to smoked tobacco....) Nimur (talk) 16:48, 10 July 2009 (UTC)

I have actually smoked coffee in a water bong without having any problems with getting it to ignite. My question mainly concerns how readily the caffeine gets from the coffee or tea being burned into your bloodstream.(I have found the smell of both tea and coffee smoke to be no more offensive than tobacco).

You might want to reconsider - haven't you heard of Coffee Worker's Lung? Nimur (talk) 17:05, 10 July 2009 (UTC)

I'm not certain of this, but I was under the assumption that if you inefficiently combust organic material (such as by smoking it), it can release carcinogens, producing a cancer risk. For example, burnt toast has some carcinogens. So whether of not it works/is as effective etc, I suspect this danger would mean it would be a less widespread method than simply drinking it. Regards, --—Cyclonenim | Chat  17:12, 10 July 2009 (UTC)

I am fully aware that inhaling smoke from burning organic material can be carcinogenic. I am not too worried about that because I don't plan on making any kind of habit of smoking either tea or coffee as i enjoy their taste and would just assume to drink them. I am just wondering if anyone knows how readily caffeine is absorbed by inhalation of smoke. —Preceding unsigned comment added by Frogmaster3950 (talk • contribs) 17:30, 10 July 2009 (UTC)

"Smoking Tea", as in the line from Mama Kin, "Sleeping late and smoking tea" is a euphemism for what the kids call "the reefer". See Urban dictionary which has some reference to the use of "tea" to mean "marijuana". this google search makes it clear that smoking actual tea will not get you high at all; except in the case of cutting off oxygen supply. --Jayron32.talk.contribs 18:10, 10 July 2009 (UTC)

I once emptied a Lipton's tea bag and rolled the contents into a cigarette. One puff was enough to explain why tea cigarettes aren't being sold. It was nauseating. B00P (talk) 06:03, 11 July 2009 (UTC)

The only way tea is worth smoking is in a closed pan over just enough heat to keep it smouldering. Slices of salmon or chicken placed over them will cook in the smoke in 15 minutes or so, developing a beautiful golden colour and smokey flavour. The tea leaves should then be discarded. - KoolerStill (talk) 12:05, 12 July 2009 (UTC)

According to Solzhenitsyn's The Gulag Archipelago, inmates in the Soviet forced-labor camps used to smoke tea, not so much to get high, as to cause self-inflicted heart and lung damage so they wouldn't have to work (the idea behind the labor camps was to literally make the poor devils work till they drop dead). FWiW 76.21.37.87 (talk) 02:27, 13 July 2009 (UTC)

Evolution of the anus

Serious question, it seems like the human body has changed a lot since our very early (similar to lungfish) ancestors. The human mouth has specialized teeth, limbs have complex hands and fingers, etc. Why does it seem like the human anus has barely changed at all. Are there any major differences between the human anus and other animals? Has the human anus evolved any particular adaptations over evolutionary history? TheFutureAwaits (talk) 18:02, 10 July 2009 (UTC)

it's one function hasn't changed at all over the many years, so why would it need to evolve? —Preceding unsigned comment added by 82.43.91.128 (talk) 18:23, 10 July 2009 (UTC)

Sure it has, the type of matter that passes through it has changed many times over the eons. Not to mention moving from an aquatic to land based environment. TheFutureAwaits (talk) 18:30, 10 July 2009 (UTC)

Unlike a lot of other higher animals we have evolved voluntary anal sphincter control which, as it turns out, is pretty useful.--Frogmaster3950 (talk) 19:17, 10 July 2009 (UTC)

Citation? TheFutureAwaits (talk) 19:28, 10 July 2009 (UTC)

A lot of other animals don't even have an anus. They have a cloaca, or similar. I think it is only placental mammals that have an anus like we do. --Tango (talk) 19:36, 10 July 2009 (UTC)

As far as differences go, off the top of my head I can't think of any other animal that has to wipe. Dogs, cats, fish, rabbits, etc, even other primates just pinch it off. No or minimal cleanup is needed after the deed is done. Dismas|^(talk) 05:28, 11 July 2009 (UTC)

I imagine that's related to the fact that, whether due to bipedalism or sexual selection or both or something else, human anuses are more 'hidden' between the gluteal muscles (buttocks) than other animals'. Our inconvenient cleanup needs are likely a result of this. Maelin (Talk | Contribs) 05:53, 11 July 2009 (UTC)

No offense guys, but so far all this seems to be is a bunch of commentary. Can no one provide any useful information? TheFutureAwaits (talk) 11:22, 11 July 2009 (UTC)

Honestly, I think the anus has been more or less an anus since well before humans were humans. I doubt the human anus is significantly different from that of any other mammal. It's just a sphincter, and its requirements have been more or less constant throughout mammalian development, hence there have been no significant selection pressures to change it. In fact the only thing I can think of is that humans have developed the need to practise hygiene due to the buttocks being in the way, but the anus itself is, I would expect, largely the same as it's been since early mammalian evolution. Maelin (Talk | Contribs) 11:50, 11 July 2009 (UTC)

Slight correction: When you say "mammal" you actually mean placental mammal. Marsupials and monotremes have different arrangements. --Tango (talk) 16:36, 11 July 2009 (UTC)

Yes indeed, my mistake. Thanks for the clarification :) Maelin (Talk | Contribs) 04:06, 12 July 2009 (UTC)

Dirty Question

No, not THAT kind of dirty, maybe kinda gross would be the better way to describe it.

Without getting unnecessarily graphic, we all know what happens when we corn.

Goes in, comes out, looks exactly the same. Little if any decomposition seems to have taken place.

How, then do our bodies derive any significant form of nutrition from it? 70.25.46.99 (talk) 22:24, 10 July 2009 (UTC)

The exocarp is the part of the corn that you poop out. Its the same bit that gets stuck in your teeth when you eat popcorn. The stuff inside of the kernel, which contains all of the starches and sugars and protein and fats, is easily digestible. That's what you get nutrition out of. --Jayron32.talk.contribs 22:36, 10 July 2009 (UTC)

Thanks Jayron! Finally an end to all those sleepless nights of wondering! :-) —Preceding unsigned comment added by 70.25.46.99 (talk) 22:50, 10 July 2009 (UTC)

Drafting

In cycling, when one biker uses the draft of another to reduce their energy expenditure, does the biker in front expend more energy "pulling" the biker behind? --71.191.104.213 (talk) 22:43, 10 July 2009 (UTC)

Almost certainly not significantly, otherwise there would be no net advantage to being in the peloton. What happens is that the group as a whole is more aerodynamic than a single rider. --Stephan Schulz (talk) 23:11, 10 July 2009 (UTC)

How about just a pair of bikers? Does the one pull the other, or does the one in the rear simply take advantage of an aerodynamic effect that is already occuring behind the first rider? --71.191.104.213 (talk) 23:22, 10 July 2009 (UTC)

It's certainly the case in car racing that when two cars get up really close, they both benefit. The amount of drag on a car is a function of (amongst other things) it's cross-sectional area. When two cars 'tailgate' each other - it's almost like the two of them are glued together into one car that's twice as long. The total cross-sectional area (and hence the drag) is the same for the two cars as it is for just one of them. When a car experiences drag, it's doing two things - firstly it's pushing the air out of the way at the front - but it's also pulling a drop in pressure at the back - and that takes energy too. In the case of our two car convoy - the one in front is paying the price of pushing the air out of the way - but the one behind is paying to pull the air back in behind it. Which of those is the most costly is hard to guess - it probably depends on all sorts of subtle details of the shape of the cars/bikes/whatever. But certainly it ought to be easier for the guy in front as well as as the guy at the back...it's only a matter of how 'fairly' the overall energy savings are split. SteveBaker (talk) 00:09, 11 July 2009 (UTC)

Some species of migratory birds fly m a V formation during migration. Does this produce a moving mass of air that assists all of them? (A single bird leaves turbulence behind that simply goes to waste.) Occasionally a straight line of birds is seen, lined in the direction of flight. Is the V formation more aerodynamically efficient than a straight line? A straight line formation is easier to take up than a V formation, so maybe it is an intermediate formation for intermediate-duration flights. I think I remember reading that from time to time the lead bird in a V formation gives its place to another bird. Is that because the lead bird has the most exhausting job, without other birds ahead of it to assist its flight? Is the 2-dimensional V more efficient aerodynamically than some sort of 3-dimensional formation? Or is it just easier to stay in formation in 2 dimensions? For a short flight, geese take up a disordered 3-dimensional formation - it is not worth the time and trouble to get into a line or line or V formation. Some non-migratory species also fly in disordered 3-dimensional swarms for short flights. Would it be more efficient for a group of cyclists to move in a V formation rather than as a disordered group? (They are necessarily restricted to 2 dimensions.) Some fish also move in disordered 3-dimensional swarms. I think that is partly to confuse predators, especially considering the sudden turns some swarms make. But probably, also, the moving mass of water created by a swarm of fish assists all of them - albeit there is turbulence within the mass of water. - GloWorm

The V formation is indeed highly efficient, but for different reasons. If you look carefully, you will see that in addition to the position, the birds also synchronize their wing beats. This allows the use of the vortices generated by one bird to be used by the next bird. See [10] or [11]. --Stephan Schulz (talk) 16:34, 11 July 2009 (UTC)

That's interesting about synchronized wing beats. But wouldn;t a straight line formation be better for that? It seems that a V formation gives each bird the advantage of only one of its leaders wings. A straight line formation would give the follower the advantage of both the leader's wings. - GlowWorm. —Preceding unsigned comment added by 98.21.109.135 (talk) 16:53, 11 July 2009 (UTC)

The bird situation isn't the same as the 'drafting' situation with cars & bikes - it's about making it easier to generate lift - not to minimise drag. Isn't it the case that (seen from behind) a bird's left wing generates a clockwise vortex and the right wing an anticlockwise one. The bird behind it needs a clockwise vortex under it's right wing and an anticlockwise one under the left...so if they flew in a straight line, there would be no benefit. However if one bird positions it's right wing behind the left wing of the lead bird - and another puts it's left wing behind the lead bird's right - then they both get half of the benefit. This would lead naturally to the V formations we see. Alternatively - (but less likely), it might simply be that each bird desires to see where it's going...I don't think that's it though...I'm going with the clockwise/anticlockwise thing. SteveBaker (talk) 17:52, 11 July 2009 (UTC)

Totally anecdotal: When I've seen geese, etc., in a line, the line has been a "half V"—that is, they aren't flying exactly in the direction of the line, but as though the line were one side of a V with the other side missing. I've also seen formations in which there was only one or two birds behind the leader on one side and many more on the other side. I don't think I've ever seen a formation such as GloWorm describes: "a straight line of birds … lined in the direction of flight." Deor (talk) 02:23, 12 July 2009 (UTC)

Dirty Question II

I know this might come off as a joke, and it sorta...kinda is.

Yet at the same time I'm asking it with genuine curiousity, because I've never been able to get a direct answer for it.

To get into Medical School, you've gotta pretty much work your ass off (pun to be intended).

In most countries you usually have to earn a separate Bachelor's degree before even being eligible.

After four years, if you happen to have exceptional grades, and if you manage to score exceptionally well on your MCAT (or similar Standardized Test depending on Jurisdiction) you might actually have a chance to be accepted into a decent Medical School.

After several more years of working your ass off (see above), you finally earn your MD (Unless you flunk out or quit), allowing you to practice as a GP.

Sorry for the long intro, but here's the question: After all those years of hard work, once earning an MD, some, for reasons I cannot comprehend, opt to further extend their grueling studies, and forego several years of a GPs salary in order to pursue a specialty in proctology. (pun finally arrived at).

My question couldn't be simpler.

Why?

Is it a matter of supply and demand? Do proctologists earn far higher incomes than GPs as a reward for having to dedicate the rest of their lives to further humanity's understanding of the human anus?

Sorry again if this comes off as a joke, but I'm genuinely perplexed by this.

Any proctologists in the house?

Oh there you are! All the way back in the rear! (Sorry couldn't help it. But still, serious question). 70.25.46.99 (talk) 22:46, 10 July 2009 (UTC)

My wife reports that, after utilizing the services of a proctologist for less than an hour, upon seeing the bill, it is quite clear what advantages that particular speciality offers the doctor. She does report, however, that the services were worth every dollar... --Jayron32.talk.contribs 22:55, 10 July 2009 (UTC)

Why not? On seeing every crevice of human anatomy in its naked glory, day in day out for 10 years, the anus, vagina and penis lose their 'eewwww- gross novelty value pretty quickly. A digital investigation of an anus is no more inherently "gross" than a digital investigation of a mouth. Yet no-one asks why would anyone choose to become a dentist.

Moreover, a huge number of people die from colorectal cancer each year, so the job satisfaction is hardly restricted to "understanding the human anus". Its about saving lives. Rockpocket 00:34, 11 July 2009 (UTC)

I completely understand how the grossness would wear off "after ten years", thing is, the OP was talking about Med School Grads, not ten year vets.

WRT job satisfaction, how is saving the lives of colorectal cancer patients more personally rewarding than saving the lives of lung cancer patients?

I'm not quite sure what Rockpocket means to say when s/he uses the term "inherently gross". Alls I know is that it's the anus that releases what I would consider some "inherently" foul smelling matter, not the mouth.

If I were the newbie still not quite immune to the "gross" factor, I'd go for the lungs.

I'm with Jayron here, unless someone comes up with an even more sensible answer. Rockpocket's first response is based on a misreading of the question, and the second is logically flawed. 76.67.137.220 (talk) 01:52, 11 July 2009 (UTC)

The exact time isn't particularly relavent. Even after a couple of years of exposure, one gets immune to it. By the time you are in a position to specialize, you have seen all the shit you could imagine, and a fair bit more. You respond to my comment about inherent distaste with a subjective response: Yes, you consider it gross. Just because you do, doesn't mean everyone else does. That, if anything, is a logical flaw. Finally, rather than dismiss an answer on whether you consider is sensible or not, you could actually check whether it is accurate. Proctologists earn a decent salary, but (in the USA in 2008) it only comes in 17th in the list of best paid specialities, behind a lot more - what you would likely consider - less gross jobs. Go figure. Rockpocket 03:11, 11 July 2009 (UTC)

I'm not sure what you mean by "GP". In the UK a General practitioner is roughly equivalent to a consultant, it's a senior job that comes after years of experience as a doctor. --Tango (talk) 02:49, 11 July 2009 (UTC)

Ah, after looking it up I see the phrase is used differently in the US. Our article is rather difficult to understand, though... --Tango (talk) 02:58, 11 July 2009 (UTC)

I once asked my urologist why he chose that particular speciality. He said that he had considered a few specialties before deciding. The reason he chose urology was due to the fact that the other doctors that he spoke to who were in the field already seemed like people that he would get along with best. There was something about the cardiac guys having a god complex from what I recall... It's been about four or five years... Dismas|^(talk) 05:16, 11 July 2009 (UTC)

Yes, you consider it gross. Just because you do, doesn't mean everyone else does.

Agreed! Perhaps I'm the only person on the planet who finds that shit stinks.

Who knows? Perhaps the rest of the world actually savours the aroma of human feces! 76.67.137.220 (talk) 08:12, 11 July 2009 (UTC)

"Finally, rather than dismiss an answer on whether you consider is sensible or not, you could actually check whether it is accurate. Proctologists earn a decent salary, but (in the USA in 2008) it only comes in 17th in the list of best paid specialities, behind a lot more - what you would likely consider - less gross jobs. Go figure."

Precisely!

Go figure!

How does that help the OP in any way other than to repeat the question?

Go figure!

Q: Go, Wikipedia people, please figure out why certain Med students decide to go into proctology because it just plain doesn't make sense to me.

A: Go Figure!

Q: Why do certain brilliant med students decide to specialize in the the shit hole?

A: Go figure!

Aren't we here to actually try to ANSWER questions? 76.67.137.220 (talk) 09:03, 11 July 2009 (UTC)

Please do not edit my comments. If you have something to contribute, do so under your own signature. Thank you. Rockpocket 19:05, 11 July 2009 (UTC)

The OP asked about Med School Grads. Your first post spoke of 10 year vets and was therefore wrong and potentially misleading. Please remove it. Thank you. 76.67.137.220 (talk) 08:07, 12 July 2009 (UTC)

Let's try. Possibly partly because of the yuk factor, or certainly a lack of glamour factor, fewer doctors choose proctology, therefore there is less competition for patients, therefore possibly higher income. There is also the social life consideration, shared with opthalmology, dermatology, cosmetic surgery, dentistry etc., that some specialities are unlikely to involve emergencies, so make a comfortable settled life possible. Cardiology, neurosurgery, orphopaedics etc. can involve unexpected call-outs and extremely long hours. Some of these necessarily involve large staffs and many assistants, therefore working at or out of a hospital. Others can be conducted as private practice from own rooms, with minimal or no surgical theatre space or gazillion dollar equipment required. So proctology allows a good living with minimal set-up costs for private practice, and "normal" working hours without emergency calls; an added bonus is the lower likelihood of being approached for free medical advice at social functions than a dermatologist or plastic surgeon might face. - KoolerStill (talk) 16:07, 11 July 2009 (UTC)

I know a few people who specialize in a certain field because of some prior tragedy related to it. If one has a family history of a certain type of cancer, one might choose a life goal to treat it in some way. DMacks (talk) 19:56, 11 July 2009 (UTC)

A compelling advantage of proctology over specialties like nephrology, neurology, and cardiology is that you can actually see the item in question during a routine examination. --Sean 14:04, 13 July 2009 (UTC)

Horse

What is "tying up": [12][13]?174.3.103.39 (talk) 23:06, 10 July 2009 (UTC)

"Tying up" is a kind of muscle spasm - aparrently it's caused by overwork and chronic tension in the muscles. Basically some form of lactic acid problem. SteveBaker (talk) 23:57, 10 July 2009 (UTC)

Is it the same as human cramp ?83.100.250.79 (talk) 15:59, 12 July 2009 (UTC)

I'm not an expert - but it looks like the causes and symptoms are kinda similar - although a 'cramp' usually means that the muscle refuses to function where 'tying up' refers to a spasm. It's hard to imagine how changing a horses' diet would affect that...but that's what appears to be being said here. SteveBaker (talk) 11:54, 13 July 2009 (UTC)

Our article lists a number of deficiencies (salt, calcium, potassium) that can cause cramps. --Sean 14:07, 13 July 2009 (UTC)