Wikipedia:Reference desk/Archives/Science/2012 January 15

= January 15 =

Clove oil coagulating in alcohol
Any biochemistry geeks here? Lately, I've been experimenting with using clove oil (specifically clove bud oil) as a clearing agent for dissected arthropod specimens, i.e. a chemical to make chitinous structures more transparent. It works great for this purpose (without degrading the tissue like bleach does), and a lot of old entomology papers suggest it for this. My only problem is that after I'm done examining the specimen under clove oil, I have to return the specimen to 70% isopropyl alcohol for storage. Typically I would do this by transferring it from the clove oil to 100% alcohol and letting the clove oil dissolve out and then moving it to 70%. Unfortunately, when I transfer the specimen from clove oil to alcohol, the clove oil often coagulates into a white goo. I've experimented with different alcohol dilutions (70% - 100%) as well as different temperatures, but I haven't been able to reliably keep the clove oil from coagulating. Does anyone have any idea what might cause this and how to prevent it? Would using xylene instead of alcohol work better? Kaldari (talk) 04:15, 15 January 2012 (UTC)
 * Clove oil is mostly Eugenol, but also contains a bit of eugenyl acetate and beta-caryophyllene . To me, it appears likely that the clove oil is too greasy for isopropyl alcohol, and the solution would be a less polar solvent.  Xylenes would be a good guess, if you're fairly confident that it won't hurt the specimen.  The other solvent to try might be an ether, maybe diethyl ether (though again, I have no clue what it would do to the specimen).  Good luck. Buddy431 (talk) 04:35, 15 January 2012 (UTC)
 * OK, more information - in my CRC, it says that Eugenol is miscible with ethanol (and diethyl ether), so I would assume it would dissolve just fine in isopropyl alcohol as well. The problem is probably the other, non-phenol constituents.  The CRC says Caryophyllene is very soluble in benzene, so you should be good with xylenes there, and I bet it will do just fine with the eugenyl acetate (it's not in the CRC).  The only question is if it will be able to take up the Eugenol itself, but I bet it will (phenol goes into benzene just fine).  The other option would be to try to get a mixture with more eugenol and less other stuff, and see if that works with the alcohol (our article claims the stem oil is more eugenol and less other.  Otherwise, you could just try straight eugenol, though that's probably a bit more expensive and harder to get a hold of). Buddy431 (talk) 04:51, 15 January 2012 (UTC)
 * I see an analysis of clove oil is available at (probably other places).  I didn't actually go through the list for solubilities, but I agree that xylene sounds like a good thing to try, maybe dichloromethane if that fails?  But why use clove oil rather than one of many other clearing/mounting media?   See  for example, which gives quite a few useful comments. Wnt (talk) 06:31, 15 January 2012 (UTC)
 * Thanks for the feedback. This is useful information. Kaldari (talk) 10:32, 19 January 2012 (UTC)

how anal sex possible?
During anal sex how 10-12 inch long penis inserted into 3 inch long Rectum? How they keep anus wide open? — Preceding unsigned comment added by Jkrchand (talk • contribs)
 * The penis is not that long. Whoop whoop pull up Bitching Betty 15:19, 15 January 2012 (UTC)


 * Assuming good faith, WHAAOE. See anal sex. 108.1.254.17 (talk) 15:27, 15 January 2012 (UTC)


 * Porn makes it look easy. It's not.--  Obsidi ♠ n   Soul   15:28, 15 January 2012 (UTC)


 * Human penis says that "While results vary across studies, the consensus is that the average erect human penis is approximately 12.9 - 15 cm in length with 95% of adult males falling within the interval (10.7 cm, 19.1 cm) or (4.23 in, 7.53 in).". The human penis is NOT as long as you claim–the probability of a randomly selected male having a 10 inch or longer penis is 0.167%. Whoop whoop pull up Bitching Betty 15:31, 15 January 2012 (UTC)
 * Ahem... If you note the indent of my post, I was replying to the OP. I wasn't contesting your post. :S --  Obsidi ♠ n   Soul   16:22, 15 January 2012 (UTC)
 * I know that Obsidian... Whoop whoop pull up Bitching Betty 16:35, 15 January 2012 (UTC)
 * Rectum is about 4.7 inches long. Average Human penis size is 5-6 inches. The tip of a long penis would enter into the sigmoid colon, see diagrams here . No idea if that is a good thing or not. --Enric Naval (talk) 15:42, 15 January 2012 (UTC)
 * From looking at diagrams, it seems improbable to me that the tip of a penis could enter the sigmoid colon - the rectum and the lower part of the colon are not sufficiently straight for that.--Itinerant1 (talk) 23:15, 15 January 2012 (UTC)


 * As with many things in sex, it's not so much about penis length but about girth. Nobody forces you to insert the whole length of your penis, and (depending on the position) it's relatively easy to control how deep one goes. Girth on the other hand can be a problem, having a relatively thick penis can be a drawback during anal intercourse because it can easily become painful for the receiving partner. By the way, I'd contest the comment above that it's not as easy as porn makes it look - not everyone enjoys anal sex, but for those of us that do, it's not like it's a terribly complicated or difficult procedure. 92.230.233.28 (talk) 16:33, 15 January 2012 (UTC)
 * Even a 12-inch long penis? o_O --  Obsidi ♠ n   Soul   16:41, 15 January 2012 (UTC)
 * Umm. I've never encountered anyone with a 12-inch penis, not even in a porn movie, so I can't really comment on that...but as I said above, length is not the issue. If our hypothetical 12-incher is of average (or slightly above average) girth, and if the wielder of said monstrous penis is careful not to penetrate too deeply, I wouldn't foresee any problems. -- 92.230.233.28 (talk) 19:51, 15 January 2012 (UTC)
 * That's because 12 inches would be a foot. ←Baseball Bugs What's up, Doc?
 * Jonah Falcon, who is sometimes said to have the world's largest penis, is claimed to reach 13.5 inches when erect. Dragons flight (talk) 21:32, 15 January 2012 (UTC)

carrots→ 13:24, 16 January 2012 (UTC)
 * I've signed out of my account due to the nature of the question but... to refute what was said above, I have seen at least one porn movie with a woman penetrating herself with a dildo that was closer to 18" than 12. She was managing to get it all the way inside herself.  Now, I'm not saying that every woman would be comfortable or even able to do this.  Though I did see it, it did NOT look like CG (or anything approaching the production values necessary), and it was not edited or have camera tricks.  Just a few minutes of continual penetration of the entire length.  At the time I saw it, I debated asking here how it was possible but decided not to for a few reasons.  184.49.116.47 (talk) 23:55, 15 January 2012 (UTC)
 * Using a sufficiently thin, long object, with some effort, lubrication, and time, you might be able to work it in gradually 18 inches (see colonoscopy and sigmoidoscopy.) But that involves careful lateral motions to navigate past Transverse folds of rectum (which normally overlap and keep things from going in or out of the rectum) and Sigmoid colon (which is S-shaped). It seems to me that thrusting range would be severely limited at that degree of insertion, and you'd stand the risk of perforating the colon, which is a very serious condition that requires an emergency surgery.
 * Besides, is there any point to go that deep? The receiving partner has the highest density of nerve endings near the surface, where the rectal wall is next to the vaginal wall (if it's a woman) or next to the prostate (if it's a man).--Itinerant1 (talk) 00:27, 16 January 2012 (UTC)

I'm going to go out on a limb and say 92 is probably not a girl, and so has different standards. 80.98.112.4 (talk) 00:01, 16 January 2012 (UTC)

Pek Van Andel won the 2000 Ig Nobel Prize in Medicine for their Magnetic resonance imaging of male and female genitals during coitus and female sexual arousal (BMJ Group). Has something similar been done with anal sex, showing what fits where and what stretches? -- 49.230.202.204 (talk) 00:35, 16 January 2012 (UTC)
 * Good luck in writing a grant application for that. {The poster formerly known as 87.81.230.195} 90.197.66.160 (talk) 09:19, 16 January 2012 (UTC)

Is the Costa Concordia salvageable?
From what can be seen in news pictures, does the Costa Concordia look like it is salvageable? The ship cost over half a billion U.S. dollars to build; I assume that a decision to scrap it won't be made lightly. On the other hand, repairing non-localized damages to a ship like that seems to be something very expensive. In terms of types of damages, what factors tend to tip the decision to salvage or scrap a ship? — Preceding unsigned comment added by 173.49.10.43 (talk) 17:07, 15 January 2012 (UTC)
 * Multiple commenters on the articles involved including some with obvious nautical experience have said that the crushing damage on the side underwater is probably extensive and the ship is likely totaled. E.g., this was just added: An italian broker and industry experts believe the ship is a total loss, with damages to be as high or higher than $500 million. Selery (talk) 17:14, 15 January 2012 (UTC)


 * A great deal of that $500M isn't building the ship, per se, but fitting it out to the high standard demanded by cruise ship travellers. There's fancy carpeting, nice wall coverings and artworks, high-quality bathrooms, beds and other furniture. There's miles of lighting and power cabling, and lots of entertainment and communications cabling (of a hugely higher standard than you'd find in a basic cargo vessel). There's TVs, computer suites, dance floors, dining rooms, cinemas, bowling alleys, hospitals, creches, climbing walls, massage rooms, spas, shops, cafes, greenhouses, painting studios, beauty salons, gyms, art galleries, and ice rinks. About half of the volume of the ship looks to be underwater, which totally destroys all that expensive fitting out. If/when they right the hull, water will inevitably slosh around, ruining a lot of the rest.    And belowdecks functions like sewerage, laundry, engines, and power generation will be badly damaged by the water too. Reconditioning the flooded engines will be a major task.  So even if they get the ship upright and floating, they'll have to rip out much of the fit-out and start again. Add to that the costs of salvage and repair, and then consider that even repaired and refitted to perfect condition, the ship's goodwill is badly impaired (would you rather sail on her, or on some other ship without Concordia's disastrous past?).  And it's so big, and so specialised, that there's a limited market into which to sell it (it's not like a RORO ferry, which you can always paint another colour and sell to somewhere far away like Indonesia). -- Finlay McWalterჷTalk 17:35, 15 January 2012 (UTC)


 * This in today's Guardian says "The ship would be out of service until at the least the end of its financial year, on 30 November. It was too early to calculate the full costs, but the company was insured up to $40m (£26.1m) for the vessel." which suggests that it is salvageable. This from today's Herald Sun says "the actual removal of the ship could take weeks and excluded the possibility that it could be cut up on site but said the details of how exactly the 114,500-tonne wreck could be taken off the shore were confidential." I guess we'll have to wait and see! SmartSE (talk) 13:31, 16 January 2012 (UTC)


 * Further discussion here on the BBC site suggesting it may be a total loss, but only time will tell. Trugster | Talk | Contributions 17:55, 17 January 2012 (UTC)

Genetic disorders
Viruses can be used to alter the genome of bacteria and mice. Why aren't they used to alter the genome of people with genetic diseases, replacing the defective copy of the relevant gene with a correct copy? Thanks. Leptictidium (mt) 20:33, 15 January 2012 (UTC)


 * They can be. See Gene therapy. Whoop whoop pull up Bitching Betty 20:44, 15 January 2012 (UTC)


 * What's relatively easy is to get a virus to splice in a chunk of DNA at random into a person's DNA. This is of some use, if they happen to lack an important piece of DNA, and if the location doesn't much matter.  Of course, this might also disrupt whatever genes now have the new chunk of DNA spliced in, so there's some risk there.  The big problem, though, is where a person isn't just missing an important chunk of DNA, but either they have an extra piece or a mutated piece, which must be removed or repaired.  That's more than we can currently get a virus to do. StuRat (talk) 02:42, 16 January 2012 (UTC)

Finding a particular old biology textbook.
(Sorry if this isn't the correct place for this question, but I don't know where else)

I remember reading a biology textbook with an article on the human brain entitled Our 1000k computer, or something similar. I would like to find a copy of this textbook. Lest there is confusion about my requirements, it really does have to be this textbook; to qualify, the title of the chapter is what is significant to me.--Leon (talk) 21:27, 15 January 2012 (UTC)


 * Can you give us any more details, like what decade it was published, how thick it was, if it's English or American and the learning level the book was aimed at? SmartSE (talk) 13:34, 16 January 2012 (UTC)


 * It was certainly English language, but that's as much as I can remember. I think its learning level was about A-level (UK) or below, though I don't know if it was a British text book.--Leon (talk) 07:51, 17 January 2012 (UTC)

Mitochondrial Eve and Y-chromosomal Adam
The article on raptio says "In historical human migrations, the tendency of mobile groups of invading males to abduct indigenous females is reflected in the greater stability of Human mitochondrial DNA haplogroups compared to Human Y-chromosome DNA haplogroups. Case in point, "Mitochondrial Eve" is estimated to be about twice as old (140,000 years) as "Y-chromosomal Adam" (60,000 years)."

Is this correct? I've always thought Eve was older than Adam because humans are predominantly polygynous, so the male ancestry tree would converge more quickly than the female one. It also seems that if you kill all the males and rape the females, that would tend to make Eve younger than Adam, because the females would have more opportunities to leave descendants while the males wouldn't. --140.180.15.97 (talk) 22:23, 15 January 2012 (UTC)


 * I would guess it depends on the precise social organisation, and the frequency of war. In polygynous societies, polygyny will cause great instability in Y-chromosome frequencies, with some men having lots of offspring and many having none, but in monogamous societies, rape will be one of the best ways of a man spreading his genetic material.
 * It's a balance between the 20-30 children which is a realistic maximum for a woman, and the uncertain number of children a particularly powerful and rapacious man could father. It seems to me it would require either a very small number of men raping a very large number of women, or a more moderate number of men raping women on many separate occasions to make a significant difference.  Removing men from the gene pool by killing them will have an effect, but removing them from the gene pool by them never marrying is nearly as effective.
 * However if you really did manage to kill all the men of a tribe, that would guarantee a reduction in the number of different Y-chromosomes, and if you killed most of them and the rest didn't reproduce that would have the same effect. So I would imagine it's the tendency to kill males that's more important than the tendency to rape females.
 * I disagree that "if you kill all the males and rape the females, that would tend to make Eve younger than Adam", because it would dramatically reduce the number of distinct Y-chromosomes while leaving the number of mitochondrial variations essentially unchanged (because most women would reproduce). --Colapeninsula (talk) 10:53, 16 January 2012 (UTC)