Wikipedia:Reference desk/Archives/Science/2010 January 10

= January 10 =

Relationship between sleep and seme* production/quality/maintenance
First, this question is serious and Wiki identified the post as "potentially unconstructive" so I hid some words but they're still deducible.

I noticed that whenever I'm deprived of sleep (less than 5 hours of sleep for 4 or days straight), my seme* becomes very fluid and more clear instead of gel-like and white. When I masturbat* in non-sleep-deprived state and then take some of it in my hand and try to let it drip down to the floor, all of it stays rigidly stuck onto my finger no matter how long I wait. But when I do the same while I'm sleep-deprived, the semen immediately drips down to the floor. Why would this be the case biologically? —Preceding unsigned comment added by Ysk1 (talk • contribs) 01:09, 10 January 2010 (UTC)
 * Seminal fluid viscosity is affected by several different endocrine processes, the most important being general hydration, which is certainly affected by sleep, although more so by intake and excretion patterns which are in turn also affected by sleep. 99.62.185.39 (talk) 01:44, 10 January 2010 (UTC)
 * WP:NOTCENSORED. Wikipedia has articles about Semen and Masturbation. Where was your post identified as "potentially unconstructive" ? Cuddlyable3 (talk) 00:03, 11 January 2010 (UTC)

Conversion efficiency.
We have a new puppy - Scott is about 10 weeks old and has been with us for 8 days. We've fed him pretty much exclusively on canned dog food - following the 1.5 cans per 10lbs of body weight that the manufacturers recommend. Scott has been eating ravenously...and the vet said today that he's doing fine - no worms nothing.

So here is the thing - in 8 days, he's gained about 4lbs. Now, the dog food can says 13 ounces per can...and he's eaten 12 cans in 8 days. That's 9.75 lbs of dog food...and it's added 4lbs of dog.

That seems like a SPECTACULARLY efficient rate of conversion of dog-food into dog. I guess some of that weight gain comes from the water he's been drinking - but I can testify that he's pooped an awful lot (I know - I've cleaned up most of it!).

Is this rate of conversion expected? What is the highest rate of conversion that's possible?

SteveBaker (talk) 02:03, 10 January 2010 (UTC)
 * Was he weighed at the same time of day both times? The difference is weight between different times of day can be quite significant (due to food and water being consumed and solid and liquid waste being excreted at different times and food being metabolised and breathed out gradually over time). --Tango (talk) 02:30, 10 January 2010 (UTC)
 * It wasn't at exactly the same time - but even so, his weight can't possibly vary by more than he eats & drinks. Conservation of mass applies even to cute black lab mix puppies. SteveBaker (talk) 06:17, 10 January 2010 (UTC)


 * A small mammal, like a dog, will convert the equivalent of about 2-3% of it's weight in glucose to CO2 and H2O per day in order to maintain its normal activity level. So for stasis a 10 lb dog would need about 4 ounces of bioavailable glucose-equivalent per day (which excludes the water content of the food and whatever portion is removed as poop).  Protein and fat have a higher energy density than glucose and so the required weight would be less by up to about a factor of two assuming fatty dog food.  Dragons flight (talk) 07:06, 10 January 2010 (UTC)


 * Ah - good info. So now I can crunch the numbers: so according to the label on the special puppy food (have you noticed how much better the labelling is on petfood than on human food?) it's 78% "moisture" 9% protein and 8% fat with the rest being mostly fiber, linoleic acid and calcium.  So the 375g of can of food has 30 grams of fat and 34g of protein - which at 38kJ/g and 16.8kJ/g means that over 8 days he probably got 13.7MJ from fat and 6.8MJ from protein - around 20MJ altogether. So if 4.5kg of dog needs around 90 and 135g of glucose-equivelant for running round and chewing shoes, ethernet cables, etc, etc (and, sadly: more 'etc') - that would be between 11 and 17MJ...but he was about 30 to 40% heavier by the end of that time - so he's using a pretty good chunk of the energy in the food just for "normal" activity.  Hyperactive puppy activity has to be pushing the high end of that limit!


 * Argh...NO SCOTT - STOP CHEWING THE ETHERNET CA@#$%^&*... SteveBaker (talk) 15:08, 10 January 2010 (UTC)


 * Congrats on the new puppy! --Mr.98 (talk) 02:41, 10 January 2010 (UTC)


 * A 2:1 ratio across trophic levels doesn't seem remotely possible. However, aren't we all 80% water? That gets you up to 6:1, which is more reasonable. You might also check with the wife and kids to verify that 12 cans of dog food is really truly honestly all the food the little guy has been given or found himself. And ask that SteveBaker if he's been handing out treats too! :) Franamax (talk) 02:53, 10 January 2010 (UTC)
 * We're talking about canned puppy food - which is basically something that vaguely resembles fatty minced up meat - so isn't the canned food already 80% water itself? SteveBaker (talk) 06:17, 10 January 2010 (UTC)
 * Must resist demonic urge to burst into song... Clarityfiend (talk) 08:25, 10 January 2010 (UTC)
 * Gives in to temptation.Cuddlyable3 (talk) 10:00, 10 January 2010 (UTC)
 * Oh the humanity...Don't we have some kind of wikiRule against posting that kind of link here? :-P SteveBaker (talk) 14:26, 10 January 2010 (UTC)
 * Steve, are you sure you are not also missing an unusual number of rats, small children, and rarely used body parts  in the neighborhood? More seriously, you should probably keep a regular log and weigh him twice daily to get a feel for the natural variations. Maybe he was particularly hungry and somewhat dehydrated when you got him - that might make a pound or two of difference all by itself. --Stephan Schulz (talk) 15:25, 10 January 2010 (UTC)
 * Yep - we're gathering more data. We bought my Wife a 'Wii Fit' for Xmas - it has a super-high-precision weighing mechanism and there is a mode for tracking the weight of your pets and producing graphs, etc.  We hadn't done a daily weighing until we took Scott to the Vet for his shots and he was weighed there.  He was certainly incredibly hungry when we got him - but that hasn't waned after a solid week of shoving food into him at the recommended rate.  But based on the calculations above - we're going to add more biscuit to his diet (aside from anything else, it's much cheaper than canned dog food).
 * I guess you could be right about a chunk of that weight being water - IF he was severely dehydrated when we got him. The animal rescue center had only had him for a few hours before we adopted him - so it's possible that his former owners had not looked after him well.  I guess we'll know that if his weight gain levels off abruptly.  We probably need to investigate the nutritional value of cat-6 Ethernet cable though - that seems to be a significant fraction of his diet. SteveBaker (talk) 03:24, 11 January 2010 (UTC)

The name of this flower?
Does anyone know the name of this flower? The picture was taken in Japan, and the photographer does not know its name either. --BorgQueen (talk) 03:25, 10 January 2010 (UTC)
 * Looks like a dogwood of some sort. Maybe Japanese cornel?  -- Jayron  32  04:00, 10 January 2010 (UTC)

Alcohol hangover cause of insomnia?
I was drinking alcohol last night. I have been hung over all day and now I cannot sleep. Is there a link?--Sleep problems (talk) 04:08, 10 January 2010 (UTC)
 * Did you perhap drink lots of strong coffee to try to "cure" your hangover? Mitch Ames (talk) 08:54, 10 January 2010 (UTC)


 * Potentially, see Possible_long-term_effects_of_ethanol. LHS at the bottom. --220.101.28.25 (talk) 11:20, 10 January 2010 (UTC)


 * Those are long-term effects. Not the same thing at all. --Mr.98 (talk) 15:30, 10 January 2010 (UTC)


 * Might you have been dehydrated? Dauto (talk) 16:06, 10 January 2010 (UTC)


 * My understanding of insomnia is that one-off bouts can be caused by all sorts of things. If you were a regular drinker and had issues with sleep, there are definite connections there, but if it is a happened-once kind of thing, I'm not sure anyone can say one way or another whether it caused it or not. Alcohol, hydration, caffeine, stress — these can all affect insomnia. --Mr.98 (talk) 16:45, 10 January 2010 (UTC)
 * My understanding is that alcohol and other sedatives, such as benzodiazepines suppress some of the stages of normal sleep, particularly the REM stage, and in withdrawal you get a kind of rebound effect that produces a disturbed sleep pattern.  Matto  paedia  Have a yarn  05:10, 13 January 2010 (UTC)

biosynthesis of LSD-like compounds: how do tryptophan and asparagine end up fusing to share the same nitrogen atom?
Well if you ignore the substitutions on the amine like compounds, LSD looks like a strange fusion of asparagine and tryptophan, sharing the same alpha-amino group. If you look carefully, the chiral hydrogen appears to be on the site of where the alpha-carbon of tryptophan would be, but the methylene carbon next to the chiral amide group appears to be alpha-carbon of the asparagine motif, as though the COOH group has been decarboxylated. Does the ergot fungus somehow really condense tryptophan or asparagine together...? John Riemann Soong (talk) 08:37, 10 January 2010 (UTC)
 * I extracted this image from a lecture by Prof. Alan Spivey. He implicates that dimethylallyl pyrophosphate and S-adenosyl methionine are involved, not asparagine. (I'll upload the pdf if you're interested in biosynthesis of other alkaloids). --Mark PEA (talk) 13:29, 10 January 2010 (UTC)

environmentally friendly oxidation of aldehydes
What environmentally friendly oxidants are out there that will selectively oxidise aldehydes into carboxylic acids without being nasty (like Cr(VI)...

Can hydrogen peroxide or O2 in the right Zeolite or heterogeneous catalyst say, oxidise a carboxylic acid without say, touching other oxidant-sensitive groups (like aromatic rings, conjugated double bonds, amines...) John Riemann Soong (talk) 09:41, 10 January 2010 (UTC)
 * What about the ideas listed in the aldehyde article in the oxidation/reduction section? Googling for "oxidize aldehyde into carboxylic acid" was instructive too. Peroxides or halogen (either radical or in a positive oxidation state) could work but you'd need something nucleophilic (either the oxidant itself or a catalyst)...the mechanism of RCHO → RCO2H is in standard orgo texts, explaining why you need to use dry conditions to stop RCH2OH → RCHO without over-oxidation. Peroxide is pretty strong so you would need a very mild catalyst that can bleed off that excess reacitivity (H2O2 with various metal catalsts is a common way to oxidatively cleave alkenes). DMacks (talk) 23:29, 10 January 2010 (UTC)

LHC - cooling
I was researching the use of superconductors in the Large Hadron Collider, and the main benefit I saw was that since the LHC operates at 1.9K, the heat produced by resistance in conventional electromagnets would be prohibitive. But thinking through it, and rereading my sources, it was unclear which way round it is. Is the LHC at 1.9K in order to support the superconductors (i.e. to allow them to operate) or is there another reason why it operates at this temperature. Am I therefore correct in my analysis above? - Jarry1250 [Humorous? Discuss.] 16:33, 10 January 2010 (UTC)
 * Reading the LHC article again, this suggests that it is only at 1.9K to enable the superconductors to superconduct. Obviously, there are other reasons (electricity cost, for example) why you'd use superconductors, but is the non-production of heat itself one of them? - Jarry1250 [Humorous? Discuss.] 16:52, 10 January 2010 (UTC)
 * It is purely an engineering issue, the temperature of the cavern is of little influence on the experiment, given that the energies of it at 300K or 2K are both negligible compared the energy of the beam line. —Preceding unsigned comment added by 92.17.53.6 (talk) 17:27, 10 January 2010 (UTC)


 * (ec) To generate the intense magnetic fields needed, extraordinarily high currents are required: . Your toaster draws, from the wall, somewhere between ten and fifteen amperes of current.  The LHC's magnets, at full operating power, are circulating ten to fifteen thousand amps.  Leaving aside the problems that would be caused by resistive heating (and the cost of all that electricity), there just isn't enough physical space around each beamline to fit in enough copper wire to do the job.  The current carried by a thousand strands of household copper wire (picture the cord for your toaster, multiplied by a thousand times) is handled by woven niobium-titanium alloy about the size of your finger. TenOfAllTrades(talk) 17:33, 10 January 2010 (UTC)
 * In essence, then, it would be impractical to generate the 8.5 Teslas required through conventional means, based on space? - Jarry1250 [Humorous? Discuss.] 17:46, 10 January 2010 (UTC)
 * Generating the current is another reason superconducting magnets are great: you ramp up the power once, close the loop, then pull the plug, and the magnet then it stays at that field as long as you keep it cold. For a conventional electromagnet, you have to keep supplying that electric current forever from an external generator. With a good enough regulator to keep it constant to avoid magnetic fluctuations (these things need a large nonfluctuating, homogenous (or at least fixed and correctable) field, not just "large but not very stable"). And it would have to run stably at a huge voltage without arcing. Ohm's Law says that to push 15kA, even if the entire LHC only has a resistance of 100Ω, you need 15MV. If the resistance drops to zero... DMacks (talk) 23:15, 10 January 2010 (UTC)
 * There are superconductors working at temperatures a lot higher than 1.9K, why not use them instead? --131.188.3.20 (talk) 08:00, 11 January 2010 (UTC)
 * High temperature superconductors tend to be both expensive and fragile. By contrast the very low temperature superconductors tend to be simpler materials that are easy to work.  In addition, superconductors break down at high magnetic field strength, but as you lower the temperature you can push towards higher field before the superconductor fails.  Dragons flight (talk) 20:44, 11 January 2010 (UTC)

1,1-diacetoethylene
Basically a Michael acceptor with two carbonyls (on the same carbon) ... kinda like the acetoacetone except there's an ethylene group where the alpha-carbon should be.

Is it a common reagent used in industry? Are there any analogues in biology? (Maybe a carboxylic acid or an aldehyde version)? It's been really hard trying to find articles or the "proper name" for compounds with structural motifs I would think are common. John Riemann Soong (talk) 21:23, 10 January 2010 (UTC)

Help! What do I call it? 2-acetoacrylic acid? Isobutylene diketone? (Or isobutylene dicarboxylic acid for the acid version?) John Riemann Soong (talk) 21:37, 10 January 2010 (UTC)


 * Do you mean this or this? If neither of those, please draw. --Mark PEA (talk) 21:44, 10 January 2010 (UTC)


 * Yeah I mean either of those. Or the aldehyde version. Or an asymmetric "mixed" carbonyl (like ketone-acid, or acid-aldehyde, etc.) John Riemann Soong (talk) 23:11, 10 January 2010 (UTC)