Wikipedia:Reference desk/Archives/Science/2011 June 13

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June 13

what are the health effects of chronic *low* blood sugar? (if there is such a thing)

Please note that nothing in this question is a request for medical advice, anyone who requires medical advice should seek the advice of a qualified doctor, rather than anonymous unqualified respondents from an online reference desk, who are liable to be completely mistaken in their understanding and assume no responsibility for anyone who kills or injures themselves or others by mistaking anything here as medical advice or relating to it in any way.

This is not a request for medical advice -- indeed, it does not relate to me or anyone I know -- but I was wondering what, if anything, the health effects of chronic *low* blood sugar are? For example if a diabetic using insulin were to be mistaken in the amounts of insulin given, but not to the point of an acute hypoglycemic attack, but, instead, consistently low (rather than high) blood sugars, so that it remains chronically below that of a healthy person by a significant amount, but not enough to cause an acute hypoglycemic ris... then is what are the health effects? thanks.

to give you an idea of my impression, it seems that unlike moderately high blood sugar, moderately low blood sugar is not something with chronic health effects - it can be an acute episode, but nothing chronic. This is my impression, since I'm having trouble digging anything up -- that's why I've come to the ref desk :)

Note: this is a question about blood sugar not blood pressure, which is a different question.

also please note that nothing in this question should be construed as requesting medical advice in any way. — Preceding unsigned comment added by 188.28.37.179 (talk) 01:01, 13 June 2011 (UTC)

An extended, boring, hunger craving- filled, Calorie restriction life-span. μηδείς (talk) 01:13, 13 June 2011 (UTC)

See Hypoglycemia (low blood sugar) and Hyperglycemia (high blood sugar) for complete explanations. Both conditions can be chronic or acute; both are serious conditions if uncontrolled. Bielle (talk) 01:23, 13 June 2011 (UTC)

(EC)An answer more responsive to the question would cite the article Hypoglycemia, which says that low blood sugar produces the symptoms of shakiness, anxiety, nervousness, palpitations, tachycardia, sweating, pallor, coldness, numbness, hunger, nausea, vomiting, abdominal discomfort, headache, abnormal mentation, impaired judgment, fatigue, confusion, and a host of other symptoms. It can also be fatal, per the article. Edison (talk) 01:31, 13 June 2011 (UTC)

Did you need to chastise us, Edison? Does it help the OP in some way to have done so? Bielle (talk) 01:38, 13 June 2011 (UTC)

Note the (EC). The preceding response by Medeis was the one I considered less than ideally responsive to the question. You and I cited both cited Hypoglycemia. Chronic low blood sugar would not be much fun, with the symptoms listed in the article cited, as well as anger and depression listed as symptoms in some of the "alternative medicine" books about the claimed widespread hypoglycemia. Chronically reduced mental efficiency might be a problem. For a diabetic on insulin or oral sugar lowering meds, there would be the constant fear that it is about to drop from a low 70 mg/dL to a disastrous 40 mg/dL. It is rare for blood sugar to be really stable in a diabetic. There would be little margin for error between "low" and "so low as to cause convulsions and unconsciousness." "Chronic hypoglycemia" was a popular pseudodisease or fad disease of the 1970's and 1980's, [1] among gluconormal nondiabetic hypochondriacs, with popular books, [2] written about how to treat it. There are many true believers in chronic hypoglycemia as a cause of a variety of ailments not widely supported by the medical establishment, who claim that 10 to 25% of the general population suffers from hypoglycemia. Drugstores sell inexpensive glucose meters which can readily tell whether blood sugar is normal, low or high. Edison (talk) 03:12, 13 June 2011 (UTC)

I am sorry for having assumed that if the person were suffering from chronic low blood sugar he hadn't just died of starvation or accute hypoglycemic shock. The question seemed to imply voluntary dieting. Life extension by such means is a common topic of discussion. μηδείς (talk) 01:41, 13 June 2011 (UTC)

There was no implication in the question that hypoglycemia resulted from voluntary dieting. Edison (talk) 03:12, 13 June 2011 (UTC)

Let's hear from the poster, who did, I believe, use the word chronic. There certainly was no question of the acute effects which you referred to, while extreme caloric restriction, which I referred to, is posited as a method of life extension. Or did I get that wrong too? μηδείς (talk) 03:38, 13 June 2011 (UTC)

Any kind of suspected blood sugar imbalance, and any kind of dieting, should be dealt with by consulting a doctor. ←Baseball Bugs ^{What's up, Doc?} carrots→ 02:13, 13 June 2011 (UTC)

Chronic hypoglycemia actually causes someone (well, at least some rat) to increase the amount of sugar transport past the blood-brain barrier. Thus some of the effects of acute hypoglycemia don't apply as the person's system adapts. Likewise, glucose transport decreases in diabetes, perhaps a bad thing for diabetics when insulin dose is too high.^[3] Wnt (talk) 03:30, 13 June 2011 (UTC)

you guys don't really get the question. (op here). I mean, if you read about "diabetes complications" you can see that if someone has a blood sugar of 8 for 20 years (instead of the normal 5.5), or on the other scale 144 instead of the normal 100, then they can get complications. That is just slightly above normal. So, what about consistently slightly below normal? Like 4 (72 on the other scale) consistently day in day out for years? Are there complications that develop over time from chronic slightly below average blood sugar? (Note: all you guys have said about headache and vomiting and passing out etc are an acute attack of way lower blood sugar. Not my question). Thanks, and sorry I might not have been the clearest possible in originally asking. Nothing here relates to medical advice in any way, this is just more of a science quesiton. --188.28.126.160 (talk) 12:20, 13 June 2011 (UTC)

The article Hypoglycemia does "get the question, and answers it. Chronically low blood sugar has a host of possible symptoms that range widely both from person to person, and for any given person. Here, for example, from the linked article (boldface mine):

Determining the presence of both parts of this definition is not always straightforward, as hypoglycemic symptoms and effects are vague and can be produced by other conditions; people with recurrently low glucose levels can lose their threshold symptoms so that severe neuroglycopenic impairment can occur without much warning, and many measurement methods (especially glucose meters) are imprecise at low levels.

Reading the article will help you understand why a simple list of chronic symptoms is not going to be very accurate, although the list of possible symptoms and consequent damage is there. Bielle (talk) 17:09, 13 June 2011 (UTC)

Bed Bugs

I don't understand why people freak out about bed bugs. They are much more benign than other blood sucking insects, such as mosquitoes and ticks (for instance, they have not been proven to transmit diseases, and only a small percentage of people actually have a noticeable skin reaction to their bites. Most aren't even aware of it.). We get bitten by other insects all the time. So why all the fuss about bed bugs? Thanks. Quinn ^{❀ BEAUTIFUL DAY} 03:30, 13 June 2011 (UTC)

People are generally unpleased to be eaten by things, even if they are only being eaten in small bits at a time. There's a general revulsion against this, which is a Good Thing, since many other blood-sucking insects and other such parasites are known to transmit real disease. That bed bugs are comparatively less disease carrying isn't necessarily a factor in the level of revulsion people feel viscerally to being eaten. It's not an intellectual response. Furthermore, while bed bugs are pretty low on the "disease carrying vermin" ladder, the presence of any vermin is usually an indication of general uncleanliness; apartment buildings with bed bugs infestations can also have other pests (fleas, rats, etc.) which are not always so benign. Even if not true in every case, the presence of vermin of any sort is generally met with revulsion, for reasons described above. --Jayron32 05:22, 13 June 2011 (UTC)

Unlike mosquitoes or ticks, bed bugs infest homes, and particularly mattresses. Bed bug infestations are easily spread, and can be difficult to eradicate. Rckrone (talk) 05:30, 13 June 2011 (UTC)

Bed bugs are like head lice, not terribly dangerous, but very paranoia inducing. HiLo48 (talk) 06:03, 13 June 2011 (UTC)

I appreciate the answers, but I would point out that bed bugs have absolutely nothing to do with "un-cleanliness:". Bed bugs are generally brought in by the last person you allowed to sleep in your bed. Whether in luggage or other such transmitter.Quinn ^{❀ BEAUTIFUL DAY} 06:27, 13 June 2011 (UTC)

Inviting unclean people to sleep in your bed isn't itself a risky behavior? How is this different from inviting someone with fleas from sleeping in your bed? --Jayron32 17:49, 13 June 2011 (UTC)

Not terribly dangerous but they can be very irritating [4] on a whole lot of levels. I'm not sure people are paranoid about them; I think they are anxious which is rather different. Richard Avery (talk) 06:27, 13 June 2011 (UTC)

There is also what might be called the tautological response — people are disgusted by bedbugs because other people are disgusted by bedbugs. That is, it doesn't matter what I think, if all my friends will find me disgusting. Or, more to the point, if my property values are going to be affected, and so on. --Mr.98 (talk) 10:10, 13 June 2011 (UTC)

I'll also mention that many people are easily disturbed by bedbug behaviors, e.g. Traumatic_insemination. Granted, this has nothing to do with the risk/dangers they pose, but who said disgust was rational? SemanticMantis (talk) 13:32, 13 June 2011 (UTC)

Interesting premise but my guess is few people are sufficiently aware of such behaviours to be disgusted by them. Nil Einne (talk) 02:57, 14 June 2011 (UTC)

A sterile home were there are none of the insects that you find outdoors in Nature is a paradise for specialized bugs adapted to live in the home environment. Count Iblis (talk) 18:03, 13 June 2011 (UTC)

I'll take exception to your "small percentage of people". Our article on bed bug infestation puts the fraction of people with no visible skin response at between 20% and 70%. While that's a pretty broad range, if we assume that the non-responding fraction really is 70% (the 'best' case) then it's still better than even odds that at least one member of a two-person household will feel the bite. It turns out that it only takes one person waking up every day covered in spots to declare that the bugs are a 'problem' for the entire household.

The infestation article (and the main bed bug article, as well) talk about some other health and cosmetic issues. Rolling over on blood-engorged bed bugs leaves unsightly bloodstains on one's sheets and body. Bed bugs suck significantly more blood than mosquitoes; a full meal is on the order of 1 mL. While that's not a large amount by itself, ten bites per night for eight weeks is 560 mL of blood. That's as much as one donates when giving blood, at about the same frequency; severe or chronic infestation can push some people over into anemia. Some people also become sensitized to the bites through long exposure.

Finally, since transmission is relatively easy – and eradication can be rather difficult – they're the bane of multiple-unit dwellings. If one resident has them, eventually the bugs spread to everyone. Unless everyone treats them simultaneously, they'll tend to return and reinfest. Even if most people aren't bothered, some will suffer quite acutely. TenOfAllTrades(talk) 13:39, 14 June 2011 (UTC)

Need help identifying this ladybird-lookalike

Hi,

Was in my garden two days ago and noticed this colorful critter crawling around on an asparagus plant.

• 
• 
• 

Colors and spots look like a ladybird. I am mostly familiar with the common seven-spotted ladybird, but I know there are other species of ladybirds. But this isn't a ladybird, is it? It is a bug trying to look like one, isn't it? The shape of the body just does not fit well with a ladybird. Any help on the id would be appreciated. Thanks,

--Slaunger (talk) 05:41, 13 June 2011 (UTC)

Hi that is a common asparagus beetle :) — Preceding unsigned comment added by 109.224.25.11 (talk) 06:15, 13 June 2011 (UTC)

Forgot to inform about the location: Viborg, Denmark. --Slaunger (talk) 06:15, 13 June 2011 (UTC)

Ok sorry about that link does not work; how ever if you type orange and black bug uk into google images you will find it there as a asparagus beetle.

Thanks for the hint. But I do not think it is a common asparagus beetle, rather a spotted asparagus beetle, Crioceris duodecimpunctata. --Slaunger (talk) 06:29, 13 June 2011 (UTC)

Well spotted!--Shantavira|^{feed me} 06:37, 13 June 2011 (UTC)

Hahaha :-) --Slaunger (talk) 07:17, 13 June 2011 (UTC)

Recent Volcanic Eruptions

With the recent icelandic eruptions and now the chilean eruption pushing vast amounts of ash into the atmosphere, would this effect global temp or would this be an insignificant event? What scale of eruption at various points on the planet would significantly effect global temp? which could by all tense and purposes reverse global warming? — Preceding unsigned comment added by 109.224.25.11 (talk) 05:43, 13 June 2011 (UTC)

Pinatubo in 1991 had a significant effect, but it was on the same scale as natural variations on top of the warming trend

These are both fairly insignificant events on the global scale. In order to see significant global cooling you need to inject a vast amount of ash and sulfates into the stratosphere, which requires an extremely energetic eruption. The current eruptions of Puyehue in Chile and Grímsvötn in Iceland are 3 and 4 on the Volcanic Explosivity Index (VEI) respectively. To give you a sense of the scales involved: Mount Pinatubo's 1991 eruption had the effect of lowering the global temperature by about 0.4 °C; this about the same as the amount of warming seen in the past 20 years (see image). However, Pinatubo's eruption was a 6 on the VEI (i.e. about 100 times more material erupted than Grímsvötn and about 1000 times more material erupted than ), had an ash column up to 21 kilometres (13 mi) high, and occurred near the equator which facilitated the spread of cooling stratospheric aerosols across the entire globe. Even with this extreme event, its cooling effect only lasted about 2 years. The current eruptions have only had ash clouds up to 10 and 12 km respectively, which is just barely into the stratosphere (if it is at all; the height of the stratosphere actually changes from day to day with the weather).

Also, your idea that a volcanic eruption could somehow "reverse" global warming is quite unlikely; the residence times of sulfates and ash in the atmosphere are on the order of a few years, while CO₂ has a residence time of about 400 years. Volcanoes also emit large amounts of carbon dioxide in addition to ash and sulfates, so I imagine in the long run the overall effect of a large volcanic eruption would be a net warming.-RunningOnBrains^(talk) 06:25, 13 June 2011 (UTC)

I realize upon re-reading that I was unclear on a few things. Volcanic aerosols (mainly volcanic ash and sulfur dioxide) suspended in the atmosphere reflect sunlight back into space, thus if you inject a large amount of volcanic aerosols into the stratosphere you can lower the amount of sunlight that reaches the earth by several percent, leading to cooler temperatures. The reason you need the eruption to reach into the stratosphere is that there is very little in the way of weather-related processes such as rain which quickly remove volcanic aerosols from the atmosphere. Ash and sulfates in the troposphere will likely be washed out on the order of weeks; not nearly long enough to cause significant cooling.-RunningOnBrains^(talk) 06:31, 13 June 2011 (UTC)

The volcanic winter article might be of interest, although it could do with some expansion. CS Miller (talk) 08:42, 13 June 2011 (UTC)

Being pedantic, but sulfur dioxide is a gas. It gets oxidized to a sulfate. -Atmoz (talk) 17:18, 15 June 2011 (UTC)

Note that the Mount Pinatubo eruption began in the early summer, while the Chilean eruption is occurring in early winter. μηδείς (talk) 18:56, 13 June 2011 (UTC)

I'm not sure that really matters, except that the tropopause (the bottom of the stratosphere) is typically a bit lower in the extratropical winter, though still around 10 km.-RunningOnBrains^(talk) 20:44, 13 June 2011 (UTC)

It matters because there's a lot more sunlight to be blocked during summer, μηδείς (talk) 01:25, 14 June 2011 (UTC)

Well, the sun-reflecting effect of stratospheric aerosols is over the course of about two years, so it could have some effect, but the effects will be spanning several seasons anyway; thus, I doubt there will be much difference what season the eruption occurs in. However, a big difference here is the ash will be mostly confined to the hemisphere the eruption occurs in due to stratospheric wind patterns, unless, of course, like Pinatubo, the eruption occurs near the equator. Tropospheric volcanic aerosols are mostly washed out of the atmosphere by rain and other processes in a matter of days, so it is really only these long-lived stratospheric aerosols that matter. -RunningOnBrains^(talk) 02:54, 14 June 2011 (UTC)

Yes, it's highly unlikely the the strongest sun blocking effects would actually occur during the time of the eruption rather than six to twelve (and eighteen to twenty-four) months after.

And what sort of magical numbers wizard could figure out what the chances are that the period starting one year to eigtheen months later will actually be during the same season as the first six months? What are we, fortune tellers? μηδείς (talk) 03:07, 14 June 2011 (UTC)

I was referring to the fact that the effect will last for more than one year, thus the dimming effect would be integrated over all seasons. Sure, maybe we'll have one more winter than summer, but unless we are talking arctic circle latitudes, this effect should be negligible. Additionally, the ash will spread to much of the hemisphere, and possibly the globe, over this time, further diminishing the seasonal impact. I'm not saying it won't matter, I'm saying it probably won't make a significant difference.-RunningOnBrains^(talk) 22:32, 14 June 2011 (UTC)

Any effect that that lasts more than a year can be discounted, since after one year you are back to the same cycle of seasons. For example SUMMERWinterSUMMERWinter or the reverse. The same with the effect spreading over the entire hemisphere, since the entire hemisphere is in the same season at the same time. I cannot find a chart of seasonal insolation, but it is obvious from this temperature graph which can stand proxy for the effect at mid lattitudes that the effect is significant. Only if there is an extremely low rate of decrease in sun blocking from an eruption over many years or if there is a very fast mixing between the hemispheres will the seasonal effect be negligible. The Mount Pinatubo eruption caused a drop in temperature in the Northern hemisphere of about 1.0 degree F and about 0.4 degrees F in the Southern Hemisphere. This does not control for season, obviously, but it does show the significant hemispheric difference, and hence imply a seasonal effect. μηδείς (talk) 16:08, 15 June 2011 (UTC)

I've done a brief literature search and only one paper appears to address the seasonal effects thoroughly: The Volcanic Signal in Surface Temperature Observations (1994). I don't have time to read the whole paper right now, but they seem to indicate that there is a significant seasonal effect. So you may indeed be right; a summer eruption (especially early summer) seems to have a greater cooling impact, with some uncertainty due to a limited and noisy data set. In regards to the OP, however, the point is moot, since the current eruption plumes are not reaching significantly into the stratosphere. -RunningOnBrains^(talk) 02:58, 16 June 2011 (UTC)

Triplet carbenes

why are triplet carbenes normally sp² hybridised but become sp hybridised when bonded to oxygen ,nitrogen ,sulphur or halides ? Raky rough (talk) 12:05, 13 June 2011 (UTC)

Does Carbene#Structure_and_bonding help? --Jayron32 17:51, 13 June 2011 (UTC)

The Carbene#Structure_and_bonding section shows two diagrams for triplet carbene .[[5]] now i can't understand how the presence of electonegative elements can change sp² carbene to sp and in the process unhybridises one of the hybridised sp² orbitals Raky rough (talk) 15:26, 14 June 2011 (UTC)— Preceding unsigned comment added by Raky rough (talk • contribs) 15:24, 14 June 2011 (UTC)

Does the attached group you are considering affect just the geometry/hybridization of the triplet, or also the relative stability of the singlet vs triplet? The article says the latter, you seem to be asking about the former. DMacks (talk) 15:33, 14 June 2011 (UTC)

well yes i was asking about the former . i was thinking about the case of trifluoromethyl radical where the strong -I effect of three fluorine atoms change hybridisation from sp² to sp³ (hence s character of hybridised orbitals decreases). but the effect of the electronegative groups in case of triplet carbene is opposite (s character of hybridised orbitals increases) which puzzles me.Raky rough (talk) 16:52, 14 June 2011 (UTC)

pressing question

why is it that if you unplug a fridge for a while, even if you clean it fastidiously, it will smell really musky. no matter how long you air it out. but lo, when you plug it back in again, as soon as it finishes cooling again, that smell is gone! why does cold desmellify in this mysterious manner. thanks for any scientific insight you might have on this question. --188.28.126.160 (talk) 12:50, 13 June 2011 (UTC)

I've tracked down the musty smell in my refrigerator to the condenser and drain pan. So, cleaning the inside of the fridge won't help with that. A long time ago, when I lived in an apartment, my fridge really stank. That is how I learned about the drain pan because I tracked it down and found that the drain pan in that fridge was full of blood. -- kainaw™ 13:08, 13 June 2011 (UTC)

(edit conflict)Possibly, because there exists bacteria on the inside surface of your fridge that isn't removed by anything short of bleach. Low temperatures negatively impacts cellular metabolic rates, explaining why you only detect a smell when the fridge is above normal operating temperature. Bacteria give off gases as a waste product of metabolism, the lower the temperature, the lower the concentration in the air. Plasmic Physics (talk) 13:16, 13 June 2011 (UTC)

That's a very good explanation. Almost too good. 188.28.126.160 (talk) 13:52, 13 June 2011 (UTC)

And that should be testable by storing said unplugged refrigerator in consistently cold conditions, say outside in locations where temperatures stay around freezing for several months at a time. Surely someone around here's done this? --jjron (talk) 14:28, 13 June 2011 (UTC)

It's not just a metabolic effect. The vapor pressure of the smelly compounds that produce the odor you're detecting also varies with temperature. Higher temperatures mean that the maximum concentration of stinky stuff in the air is also higher; higher temperatures will also tend to drive faster evaporation of these nasties. Your nose can detect some odiferous compounds at concentrations of parts per billion or even less, so it takes a very small reservoir of these compounds in the fridge (tucked into crevices, hidden in door seals, even just adsorbed on the plastic surfaces) to continue to release odor for a very long time. TenOfAllTrades(talk) 15:10, 13 June 2011 (UTC)

I knew it.. 188.28.126.160 (talk) 19:18, 13 June 2011 (UTC)

Strontium ferrite vs. barium ferrite

Which is more likely to be found in common household magnets? Or are they a mixture of both? --Chemicalinterest (talk) 16:11, 13 June 2011 (UTC)

I don't know but you could try an experiment, construct a rudamentary spectroscope using a prism, a gloss black backdrop, a candle, and a piece of cardboard with a narrow slit cut into it. Prepare a concentrated solution, by dissolving a few tens of miligrams into 5 ml of hydrochloric acid. Arrange the backdrop, prism and cardboard in such a way so that light from the lit candle is shining through the slit is reflected and refracted through the prism onto the backdrop. Once you have the experiment set up, dip a piece of iron wire in your solution. Hold the dipped end in the flame of the lit candle, and observe the spectrum on the backdrop, this works easier in the dark. Compare this spectrum to those of strontium and barium, I'm sure you know what to do with those. Plasmic Physics (talk) 14:53, 15 June 2011 (UTC)

body

what are the harmful effects of masturbating? — Preceding unsigned comment added by 117.224.212.237 (talk) 16:57, 13 June 2011 (UTC)

Do you consider sticky fingers harmful? Googlemeister (talk) 17:17, 13 June 2011 (UTC)

Chafing.-RunningOnBrains^(talk) 17:19, 13 June 2011 (UTC)

I think Jocelyn Elders answered this question accurately. Wnt (talk) 17:40, 13 June 2011 (UTC)

Lube. -Atmoz (talk) 17:09, 15 June 2011 (UTC)

Depending on your social environment, there are taboos in some societies about masturbation, so you could suffer socially. There are lots of different cultures in the world, each with their own opinions on these things, and depending on which culture you find yourself in, you may experience various levels of social consequences from masturbation. --Jayron32 17:46, 13 June 2011 (UTC)

There are no known harmful health effects from masturbating. thx1138 (talk) 18:13, 13 June 2011 (UTC)

WebMD has some funny stuff up, that frequent masturbation is correlated with an increased risk of prostate cancer in men in their 20s and 30s, but a decreased risk in men in their 50s.^[6] Wnt (talk) 18:23, 13 June 2011 (UTC)

Yes, but in that article the researchers say that the frequency only indicates the sex drive, which in turn is a function of the level of hormones. A man's prostate can't tell whether orgasms come from masturbation or intercourse - probably, how would it? Itsmejudith (talk) 21:23, 13 June 2011 (UTC)

There are also these experts: She-Bop Dancing with Myself

Portnoy's Complaint _does_ highlight one disadvantage - the real thing is rather disappointing and difficult in comparison. I recall a story on Fark [7] some years ago (not the most reliable of sources, of course) about Japanese men who suffer from this problem, although I'm sure it's applicable across the world. Tevildo (talk) 20:20, 13 June 2011 (UTC)

Note to self: If I ever get engaged to marry, I've got to refrain from jacking off from that time onward. However, I've got to point out that even if this is true, 45 times a year translates to roughly once every 8 nights, which is not too bad -- in fact, AFAIK the world average for married couples is "only" once every 7 nights. 67.169.177.176 (talk) 23:22, 13 June 2011 (UTC)

Hmm the Durex surveys says 103 times a year is the average [8] [9]. This includes all non-virgins surveyed, married or not. However my impression is despite some misconceptions, most surveys show married people usually have sex more often then unmarried. Of course surveys of that nature usually have a big question mark due to the likelihood of people lying. Also the 2007 one at least, uses the internet for many countries and which would likely lead to a bias towards those who are richer and may have more free time (and more likely to be living together if married or in a relationship).

But the Durex surveys are the ones that get reported, if others exist that have tried to study the frequency of sex over a range of countries I haven't seen them (not something I've really looked for). BTW an interesting thing I noticed, while frequency of sex has a strong impact on sexual satisfaction (well that's what the 2007 survey said), some countries like Nigeria have relatively high satisfaction despite relatively low frequency of sex.

To bring this mildy back on topic, it's worth remembering masturbation is not solely a solo practice. In fact our article says

Contrary to conventional wisdom, several studies actually reveal a positive correlation between the frequency of masturbation and the frequency of intercourse. One study reported a significantly higher rate of masturbation in gay men and women who were in a relationship.

Given that, while masturbation is safer then many other practices; if you do masturbate with a partner you should use safer sex practices and birth control where necessary. If you don't while arguably not a harmful effect of masturbation per se, there's a slight chance this could lead to pregnancy or a STI.

Nil Einne (talk) 04:40, 14 June 2011 (UTC)

103 times a year? That's twice a week, which is very good indeed! 67.169.177.176 (talk) 21:42, 14 June 2011 (UTC)

Normalizing Associated Legendre Polynomials to get Spherical Harmonics

Hi all. I've been working on this problem for like weeks, and I can't seem to figure it out. I'm trying to normalize Associated Legendre polynomials to turn them into Spherical harmonics. The integral comes out to:

$\int _{-1}^{1}P_{\ell _{1}}^{m}(x)P_{\ell _{2}}^{m}(x)dx={\frac {1}{A^{2}}}$

where $A$ is the normalization constant. $A$ can be found in Spherical harmonics#Orthogonality and normalization. I know that it involves integrating by parts $\ell +m$ times, and that the boundary terms vanish in each case, but I'm not sure why they vanish. Can anyone point me to a (very detailed) discussion of how to actually do the integral, or maybe a better way than by parts? Thanks!--Dudemanfellabra (talk) 21:01, 13 June 2011 (UTC)

This question would probably be better on the Maths desk. Tevildo (talk) 23:57, 13 June 2011 (UTC)

This problem comes up while determining the Hydrogen wavefunction using the Schrödinger equation, so it's kind of physics and math. As such, when I asked here, I also started a thread at the Math desk as well. Just in case a physicist stops by here, I wanted them to see it.--Dudemanfellabra (talk) 02:34, 14 June 2011 (UTC)

It may be easier to use the definition of the states |l,m>, so you say that you get |l,m> by applying L^(-) l-m times to |l,l> And then you compare this |l,m> in the angular basis with the definition of P_l^m. Count Iblis (talk) 15:24, 14 June 2011 (UTC)

Cleaning styrofoam

I have a styrofoam cooler that I use all the time, just for ice and soda so it really doesn't get funky because no foodstuffs are in it ever. Anyway, after a lot of use, the inside is a bit yellowed and has a slightly musty odor, so I thought I'd put some water in it with some bleach (about one-half cup bleach to a half-gallon of water is what I usually use for such applications, I guess that's a 1:16 mixture). This works great for mildew and the like. However, my friend told me that bleach and styrofoam are a bad mix, that they give off deadly fumes. Of course, I am now terrified to do this, especially indoors. Is there validity to this? I guess I should be very precise: My household bleach doesn't say what's in it but does say that it "CAUTION, CORROSIVE! contains sodium hydrochlorite". The styrofoam does not say exactly what it is but it is marked with a triangular recycle symbol with a 5 inside, and says just below that, "PS"--maybe PolyStyrene? Note that there's nothing on the bleach label's caution list to single out styrofoam, but of course it can't list every stupid thing anyone might try, so I'm not putting any store by that. Oh, and if anyone knows of an alternative method that works well with styrofoam, of course I'm all ears.--108.54.17.250 (talk) 23:03, 13 June 2011 (UTC)

My friend says I'm inhaling deadly fumes. Reference desk, can I continue or is he right? --188.28.126.160 (talk) 23:15, 13 June 2011 (UTC)

Are you the same identity as the the above IP? If you are not, what are the fumes originating from? Plasmic Physics (talk) 23:26, 13 June 2011 (UTC)

Polystyrene is pretty chemically inert (like most other plastics), so I don't think it will react with chlorine or sodium hypochlorite (at least, in the absence of a catalyst such as aluminum chloride), much less in a way that releases deadly fumes. At worst the plastic might become chlorinated and further discolored, but even this is rather unlikely. You don't need to worry about poisoning yourself. As for an alternative method: I don't have a clue. 67.169.177.176 (talk) 23:33, 13 June 2011 (UTC)

Well, whatever you do, don't clean it with acetone. Plasmic Physics (talk) 00:42, 14 June 2011 (UTC)

Bleach fumes are caustic, but I don't think the Styrofoam contributes a bit. I use bleach on them outside, so the fumes can dissipate. I just cleaned one that way last week, as a matter of fact. Make sure it's somewhere kids or pets won't get at the bleach, though, if you leave it out to soak in bleach, as I do. StuRat (talk) 00:50, 14 June 2011 (UTC)

Dear God. Styrofoam coolers are like $5.00 or so. If its so nasty it can't be cleaned, recycle the old cooler and buy a new one. This is a penny-wise-and-pound-foolish issue on two regards: 1) You are likely spending more money and effort on cleaning the cooler than the cost would be to just buy a new one 2) Harsh cleaning chemicals have a greater environmental cost than recycling an old cooler would, or probably even just throwing it away. You are seriously better off just buying a new one. If you can keep it for, say, 5 years, I don't think a dollar a year is too much of an investment for cold beer... --Jayron32 01:09, 14 June 2011 (UTC)

You seem to assume a cooler only needs cleaning once every 5 years. In my experience they need cleaning every time they are left closed up for a while. I get bleach for a dollar a gallon, so can do a lot of cleaning at that rate, before it would pay for a new cooler. And can you recycle Styrofoam ? The best I could manage was to reuse one as an (ugly) planter. StuRat (talk) 04:16, 14 June 2011 (UTC)

Of course you should clean it frequently, but at some point its important to know when to cut one's losses. When the cheap, disposable styrofoam cooler can't be cleaned by normal means and resists anything except exotic cleaning agents or requires an extensive committee discussion to arrive at a possible cleaning method, it's time to cut bait and start over. I'm quite a frugal person myself, and I quite support using items wisely, but even I have my limits; at some point you've just got to buckle down, and dip into those savings for that new styrofoam cooler... --Jayron32 04:25, 14 June 2011 (UTC)

You consider bleach to be exotic ? To me it's the most basic cleaning agent there is. :-) I doubt that it's as bad for the environment as detergents. Once fully diluted, the only harmful effect I could imagine is it making rivers and lakes less acidic, but that would take a massive quantity, and, due to acid rain, some movement in that direction might even be beneficial. StuRat (talk) 04:43, 14 June 2011 (UTC)

No, not really. I clean my cooler with it all the time... --Jayron32 04:44, 14 June 2011 (UTC)

Then I don't understand your previous posts. StuRat (talk) 04:47, 14 June 2011 (UTC)

Then we're both fooked, because I hoped that at least you could shed some light on them. I am quite baffled myself. --Jayron32 05:32, 14 June 2011 (UTC)

Diluted bleach solution shouldn't hurt the cooler, though depending on its precise composition you might get further yellowing. As Jayron says, you might consider the acquisition of a new cooler. Twenty bucks will get you one with a hard plastic shell and snug-fitting (possibly hinged) lid. They are better-insulated, so the beer stays cooler, longer. They're more durable and they won't chip off bits of unsightly styrofoam fluff if you bang them around a bit. (They'll also stay intact and closed if you pack them under all your luggage in the trunk of the car.) They have proper carrying handles, some have drain spigots to remove excess meltwater, and in a pinch you can sit on them. The interior hard plastic lining is non-porous, so it won't pick up odor quite as readily as exposed styrofoam, and can handle vigorous scrubbing. Yes, they're slightly heavier than the naked styrofoam coolers, but once you load them up with beer and ice the weight of the cooler is pretty negligible—and you may be glad of the carrying handle(s). For all coolers, you'll cut down a great deal on the mustiness if you leave them open (at least a little bit) after you clean them out, at least until the interior is completely dry. TenOfAllTrades(talk) 13:18, 14 June 2011 (UTC)

I have several large coolers of the type you describe; one I use a lot is a large cylindrical cooler, which I actually use when brining and/or marinating large roasts (whole turkeys, pork butts, stuff like that). Very convenient, and easy to drain off the brining fluid into the sink for disposal. I usually clean it with straight bleach afterwards, including cleaning out the drain spout with bleach and a small bottle brush. It probably cost me $30 dollars, and besides the meat preparation applications, I have used it for keeping beers and sodas cold as well. Much easier to work with than styrofoam... --Jayron32 15:11, 14 June 2011 (UTC)

(un-indent) "And can you recycle Styrofoam ?" -- Yes, polystyrene is fully recyclable, though for some reason (probably because it's so cheap and readily available) it doesn't get recycled to nearly the same extent as, say, PETE. There are AFAIK no particular technical obstacles to recycling styrofoam -- the only obstacles, if any, are economic and/or political.

"I doubt that it's as bad for the environment as detergents." -- Even if BOTH detergents AND chlorine bleach are used, the environmental impact from such small quantities of them will be negligible to nonexistent. All this "environmental impact" stuff has been deliberately hyped by Greenpeace and other likeminded eco-fascists eco-Luddites for at least the past thirty or forty years. 67.169.177.176 (talk) 21:55, 14 June 2011 (UTC)

I object to the malignment of Greenpeace (see article) as a fascist organization because Greenpeace does not accept funding from governments, corporations or political parties. Anionic detergents with branched alkyl groups were largely phased out in economically advanced societies because they are poorly biodegradable Bleach is toxic to fish and invertebrates, in confined spaces. Cuddlyable3 (talk) 12:26, 15 June 2011 (UTC)

While I agree on second thought that fascist in the strict sense of the word is not really applicable to Greenpeace (they are more accurately described as marxist, third-worldist and eco-Luddite), I must point out that accepting funding from governments, corporations or political parties is not a criteria for being considered a fascist organization (or any other kind) -- this depends SOLELY on the ideology being advocated. Linear alkylbenzylsulfonates that are in universal use as detergents today (as opposed to the obsolete branched ones you're talking about) are biodegradable and nontoxic -- to claim that all detergents are environmentally harmful when in fact this is a property only of a specific subset that is no longer used is fallacious at best and deliberately misleading for political purposes at worst. Fish and invertebrates don't naturally occur in "confined spaces" as the latter term is commonly understood. 67.169.177.176 (talk) 16:58, 15 June 2011 (UTC)

By the way, how can you be so sure that "Greenpeace does not accept funding from corporations or political parties"??? 67.169.177.176 (talk) 17:15, 15 June 2011 (UTC)

Like you I read Wikipedia that says: The global organization [Greenpeace] does not accept funding from governments, corporations or political parties, relying on more than 2.8 million individual supporters and foundation grants.. If you have verifiable information that should be in the article then add it. Cuddlyable3 (talk) 19:30, 15 June 2011 (UTC)

You can't always trust what Wikipedia says because it has a Marxist bias itself; as a matter of fact, I've been boycotting it for a year or so to protest against the actions of a certain commie scumbag re. the article Extermination through labor. In any case, you can't take documents written and published by the organization itself at face value without verifying this info with an independent, reliable, unsympathetic source (which Gilbert demonstrably isn't, as the title of her work clearly indicates her sympathies with the environmentalist movement). As for the matter of Greenpeace taking funding from corporations, there is the book The Hidden Face of Greenpeace by Olivier Vermont, where he alleges that Greenpeace has in fact been extorting racket money from various corporations. 67.169.177.176 (talk) 20:39, 15 June 2011 (UTC)

And even if in fact they do not take corporate money, that still doesn't prevent them from being third-worldist Luddites with Marxist political views -- this can be proved or disproved by their statements and actions alone. 67.169.177.176 (talk) 21:03, 15 June 2011 (UTC)