Wikipedia:Reference desk/Archives/Science/2015 December 30

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December 30

Why do large ships have water shooting out of their hulls?

Like this on the side. — Preceding unsigned comment added by ScienceApe (talk • contribs) 01:55, 30 December 2015 (UTC)

Bilge pump. AllBestFaith (talk) 02:07, 30 December 2015 (UTC)

Seawater cooling overboard discharge. See the description in section 2.1 of this EPA rule, starting: Seawater cooling systems on surface ships and submarines provide cooling water for heat exchangers, removing heat from the propulsion plant and mechanical auxiliary systems. -- ToE 02:30, 30 December 2015 (UTC)

On old steamships, a coal ash slurry was discharged over the sides to remove the waste from the engines. Rmhermen (talk) 03:39, 31 December 2015 (UTC)

Epidemiology of scoliosis

According to scoliosis, An estimated 65% of scoliosis cases are idiopathic, about 15% are congenital and about 10% are secondary to a neuromuscular disease. 65+15+10 = 90, too big of a gap to be merely a rounding error. The source is offline, so I can't consult it, but apparently it's in line with the source; someone understood this situation as a typo and changed 65 to 75, but the edit summary by the reverting editor makes me assume that these three numbers are correct.

This all being the case, what happened to the other 10%? I can't ask the reverting editor, who hasn't been here since May. Nyttend (talk) 06:07, 30 December 2015 (UTC)

As I read it, the reverting editor is not saying that the correction to 75% was necessarily wrong, but only that "You were guessing which number to change; don't do that". Anyway, it's entirely possible that there is no error, and the remaining 10% of cases originate from any of several other known causes. This page supports that suggestion, but I don't know how reliable a source it is.

As to the source cited by the article, it's the 2008 edition of a book by Steven S. Agabegi and Elizabeth D. Agabegi. That edition may not be online, but the 2013 (third) edition is available in Google Books in limited preview mode. However, unless something's wrong with Google's search of it, it does not seem to make any statement at all on this subject. --76.69.45.64 (talk) 11:23, 30 December 2015 (UTC)

Driverless cars and the future of radio

Greetings!

I've recently been pondering the advent of driverless automobiles and whatever fate that they may spell for broadcast radio. Let me elaborate.

Once upon a time, radio stood as the undisputed king of all media, before broadcast television, community-access television, and Internet all appeared. Now, however, much—if not most—of its audience comes from car and truck operators who listen whilst driving. (Indeed, under the status quo, they cannot safely watch TV or surf the web when behind the wheel). If one day, however, driverless cars become so safe, reliable, and ubiquitous that manned vehicles disappear from our roads—akin to horses and chariots before—then how would this affect broadcast radio?

Namely, A.) Would AM and FM (or at least AM) become so unprofitable that it would disappear just like the telegraph and the telex before? I mean, one can imagine that most people in said vehicles would rather view shows, movies, and websites. B.) How would government and communications companies reallocate the wireless spectrum? Would the end of AM, FM, and low-power FM radio result in a vast increase of television channels, cheaper cellular-phone service, and other tangible benefits? And C.) Since most radio stations continue to operate on analog signals, would their elimination result in a "cleaner" (for lack of a more proper term) spectrum with less possibility for interference of different frequencies?

Thank You. Pine (talk) 10:30, 30 December 2015 (UTC)

See the top of the page: "We don't answer requests for opinions, predictions or debate." --76.69.45.64 (talk) 11:14, 30 December 2015 (UTC)

We shouldn't speculate here but we can cite other sources that may be relevant- here's an interesting post on the future of AM spectrum [1]. SemanticMantis (talk) 15:18, 30 December 2015 (UTC)

Note that driverless cars with passengers will, at least in the immediate future, rely on a human driver as a backup, so that person should watch the road, which means no video. StuRat (talk) 18:31, 30 December 2015 (UTC)

The article Autonomous car distinguishes between vehicles that offer the driver part-time self control and potential true driverless cars without a steering wheel. The article quotes sourced predictions that include "the artificial intelligence necessary for a driverless car will not be available anytime soon....Detroit car makers believe the prospect of a fully self-driving car arriving anytime soon is pure science fiction" by Raj Rajkumar, director of autonomous driving research at Carnegie-Mellon University. The radical step envisaged of eliminating analog radio stations would render huge amounts of equipment obselete and, in the case of the MF band, sacrifice thousands of audio channels in an attempt to 'liberate' enough spectrum for one TV broadcast, which would be receivable only on an impractical antenna due to the wavelengths concerned. AllBestFaith (talk) 19:48, 30 December 2015 (UTC)

It's worth noting that in many places, broadcast radio is still struggling a lot due to things like differing consumer demands, the ease of people having and playing big libraries of media, streaming audio over mobile connections, podcasts, internet radio (some of which are the same as broadcast channels but some of which aren't) etc. While it's not nearly as bad as broadcast TV, it's hardly stellar either. Nil Einne (talk) 14:35, 31 December 2015 (UTC)

Broadcast TV is in trouble ? I have more broadcast TV channels than ever. I watch them for things like news and weather, and use Netflix or similar sites for movies. Cable/satellite TV seems to cost like $100 a month here, and that's absurd, in my opinion. My mom just switched from cable to broadcast TV. I think cable and satellite are in trouble, as people don't want to pay high prices for bundles of hundreds of channels, most of which they don't want. StuRat (talk) 17:34, 31 December 2015 (UTC)

Netflix isn't broadcast TV under most common definitions, but cable and satellite TV generally are, although I was mostly thinking of FTA broadcast TV (which includes some satellite, but not generally cable) supported entirely by ads (in some countries there is government support or other funding models, although these aren't necessarily complete i.e. they network also needs to make money some other way like with ads). Which isn't to say there isn't a problem for subscription based broadcast TV, it's worse particularly given their reliance on bundling, but the original discussion seems to have been about FTA radio so I followed in that vein.

The digital revolution has made broadcasting to wide audiences significantly cheaper (in particularly given the effectively reduced cost of spectrum licencing as you don't need much spectrum), but it's still not free and perhaps more significantly, producing the content definitely isn't. For minor channels their content can be produced or licenced if it comes from somewhere else fairly cheaply, but for more major channels they do often spend a fair amount on producing their shows (and in some places this includes producing shows they later don't air or who it turns out no one wants to watch). Plus when it comes to licencing, one reason why it's so cheap is because few people want to licence it but the licencing revenue may not come close to the production cost which may have come from the original broadcasters (i.e. if that original broadcaster isn't able to support themselves, you won't have the content.

And Netflix is in fact one of the key problems, plenty of people are using NetFlix, Hulu, Amazon to watch content, or simply pirating it rather than watching it on broadcast TV.

Even for those few people who are still watching broadcast TV, many of them are using PVRs which make skipping ads simple. This is particularly the case with those considered the key advertiser demographics at the current time. Those who aren't doing this are mostly fairly old people who aren't considered a particularly attractive demographic.

BTW, producing news broadcasts isn't cheap, these are frequently not self funding. In other words, it's generally the case that people have to watch other shows on the network, with ads, for there to be enough money to produce the news programme. If the only thing people watch broadcast TV for is the news, there's no way the news is going to survive in current form based on the current funding model. News or current affair programmes tend to be even worse. The problem isn't as acute as it is for written news, but it's still a problem in many places which rely on the advertising (or subscription) funding model.

Even for entertainment programmes, while Netflix etc are producing their own content, I don't think it's totally clear whether they will be able to support all the shows currently on them many of which are produced for broadcast TV.

In other words, key funding for the production of these shows is still coming from broadcast TV (in this case we might as well include both FTA and subscription/pay TV), so without broadcast TV, it's likely the shows have to be different or we'll have fewer of them.

There is some discussion at Cord-cutting, although it mostly concentrates on pay TV. (Despite the name, cord cutting generally includes those simply switching off terrestrial broadcast TV even though they will often have a wired internet connection to cord cut whereas terrestrial broadcast TV just requires an antenna.) [2] has some discussion although it mostly concentrates on the US which I wasn't thinking of so much. [3] has some more discussion, including considering the UK (which as the earlier source mentions, is somewhat different given that one of their key players already has a different funding model although there is continual controversy over that model plus it currently requires people to watch live content or it's screwed), [4] has a bit more. Perhaps linear TV is a better term to use, but broadcast TV is basically always linear TV.

Nil Einne (talk) 07:39, 1 January 2016 (UTC)

A lot of the new sub-channel stations on broadcast TV are old reruns, but I don't mind that, since many are better than current programs. For example, I've been watching The Drew Carey Show, which I find a lot funnier than many current shows (I was too busy to watch when it first ran). And I don't have a way to bypass ads. So, cheap shows and ad revenue. StuRat (talk) 04:57, 2 January 2016 (UTC)

I apologize for wasting your time. I didn't realize how out-of-scope this topic was for the reference desk; although, I do appreciate the resources to which you have pointed me. Thank you very much for those. It has indeed been a long year. Pine (talk) 08:43, 31 December 2015 (UTC)

Resolved

elephants

Can elephants masturbate themselves with their long trunks? — Preceding unsigned comment added by Archerlaugher (talk • contribs) 19:12, 30 December 2015 (UTC)

Yes - see Non-reproductive sexual behavior in animals#Autoeroticism or masturbation. Tevildo (talk) 20:54, 30 December 2015 (UTC)

Strictly speaking that article says that elephants "practice autoeroticism", and also "masturbate one another with their trunks" (my emphasis); it does not say that elephants masturbate themselves with their trunks. (The article describes a variety of methods of autoeroticism, in animals in general.) Mitch Ames (talk) 00:57, 31 December 2015 (UTC)

Various youtube videos (that can be left as an exercise to research) show elephants manipulating (trunk-ulating?) other elephants' genitals, so they obviously have the means and opportunity. Do you think elephants have another method that we don't know about and could learn from? AllBestFaith (talk) 01:26, 31 December 2015 (UTC)

"Various youtube videos ... show elephants manipulating ... other elephants' genitals" — Do any videos show elephants manipulating their own genitals?

"Do you think elephants have another method that we don't know about and could learn from?" — Non-reproductive sexual behavior in animals#Autoeroticism or masturbation describes some methods (which do not require a trunk) that are used by animals. Some of those methods may be feasible for an elephant. Mitch Ames (talk) 02:23, 31 December 2015 (UTC)

I'm presuming AllBestFaith is thinking mostly of the use of hands, which elephants don't have, or feet (which elephants do have, sort of but perhaps not with the level of control or ability to reach the genitals) but it's not like these methods without hands are restricted to non humans animals anyway. Our article Masturbation#Male briefly mentions lying down and rubbing the penis against a mattress or pillow and you obviously could use (and I'm sure there are people who use) other stuff. Human methods of supporting themselves would be somewhat different from many other animals given bipedalism, but the general concept is not necessarily that dissimilar. Nil Einne (talk) 13:43, 31 December 2015 (UTC)

Simple question, can an elephant reach it's genitals with it's trunk ? StuRat (talk) 01:30, 31 December 2015 (UTC)

Simple answer, YES! Alansplodge (talk) 17:28, 1 January 2016 (UTC)

Looks like his genitals met him halfway. StuRat (talk) 04:49, 2 January 2016 (UTC)

Feet

Is there a rational explanation for foot fetishism? What evolutionary purpose does it serve? 185.64.47.94 (talk) 19:22, 30 December 2015 (UTC)

A 2008 study found that males with fetish Paraphilia had a greater number of older brothers, a high 2D:4D digit ratio (which would indicate excessive prenatal estrogen exposure), and a greater probability of being left-handed, suggesting that disturbed hemispheric brain lateralization may play a role in deviant attractions. These observations point to prenatal neurodevelopment but not directly to any theory of human evolutionary survival (or supposed purpose) which in any case would need to operate over a much longer time scale than foot fetishism has been observed. AllBestFaith (talk) 20:28, 30 December 2015 (UTC)

More like pair-o'-feet-lia. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:11, 30 December 2015 (UTC)

Evolution doesn't have a purpose, nor is every behavior predetermined by a magical god you seen to be calling Evolution. --Jayron32 21:16, 30 December 2015 (UTC)

I corrected the indent to your post that addresses the OP and not the preceding 2 responders. AllBestFaith (talk) 21:27, 30 December 2015 (UTC)

I corrected your indent level, to indent one from the OP, since that's what you were responding to. But, I agree with Jayron's unreferenced assertion. Less common sexual attractions may not have an evolutionary purpose, they may just be a brain malfunction. However, if it were to have an evolutionary advantage, I suppose a mate with healthy feet may be more likely to survive to raise children, especially in a primitive society without foot doctors. StuRat (talk) 01:36, 31 December 2015 (UTC)

I corrected AllBestFaith's indent because his/her response was to Jayron, then corrected StuRat's indent because he was addressing AllBestFaith. Akld guy (talk) 06:58, 31 December 2015 (UTC)

Nope, my comment was a response to Jayron. StuRat (talk) 07:00, 31 December 2015 (UTC)

No, it was a response to both. But at least we agree that your indent change on AllBestFaith was wrong. Akld guy (talk) 07:08, 31 December 2015 (UTC)

No part of my response was to AllBestFaith (my response was to Jayron on correcting his indent level). StuRat (talk) 17:28, 31 December 2015 (UTC)

If you're going to address two people in the same post, make clear who you're addressing, because that became confused after you changed the indent. Akld guy (talk) 02:13, 1 January 2016 (UTC)

(ec) Jayron, what you say is exactly right. To add, it is beneficial for any species, H. sapiens included, to have a certain amount of intraspecific genetic and phenotypic diversity. Indeed, animal species or populations with low genetic diversity (such as cheetahs or tasmanian devils) are at high risk of extinction. That is due to reduced ability to adapt to changing environment, increased probability of being homozygous on an allele that produces a detrimental recessive trait, reduced variance in immune response (shared susceptibility to pathogens), and reduced variance of behavioral adaptations and responses, to name a few. Simply put, diversity is a good thing, and Partialism may be just one aspect of that diversity. --Dr Dima (talk) 01:45, 31 December 2015 (UTC)

the toe brain's connected to the...

• Two things. Sexual selection--nice feet are healthy feet--and two, see sensory homunculus and tell me what is next to genitals. μηδείς (talk) 04:28, 31 December 2015 (UTC)

Qing Dynasty sex manuals listed 48 different ways of playing with women's bound feet. This peculiarly painful pedicure perpetrated in 19th century China amounted to pre-selecting a preferred daughter for an upper class marriage where she would not (could not!) do field work. The reformer Liang Qichao criticized the practice with a Lamarckist eugenics argument that it weakened the nation, since enfeebled women supposedly produced weak sons. I apologise to the OP for unsourced commentary about a magical god that no one has seen, nor could infer from the question unless personally preoccupied with some unrelated fetish. AllBestFaith (talk) 18:35, 31 December 2015 (UTC)]]

Mere anatomical proximity in the of two regions processing tactile (or other somatosensory) stimuli from different regions of the body does not necessarily suggest a high degree of shared sensory afferance between these regions. Sometimes that is the case for modalities placed close in the somatotopic map, and other times not. In this instance, your assumption (which others have made) suggest that there is neither a strong connection in sensory afferance between the feet and the genitals and also that the feet do not place a large role as erogenous zones for most people[5]--by virtue of how the mere tactile sensations affect people anyway; obviously some people find them to be highly sexualized in other ways relevant to psychological eroticism. There is an alternative in speculation about the exact relationship of these two regions of the homunculus, but it is uncertain to say the least: [6], [7].

I may have misinterpreted what you meant to imply about the relevance of the relationship your suggested between perception in sensation in these two parts of the body, vis-a-vis foot-binding, but ti seemed as if you were suggesting that distorting the shape of the feet would also impair function in the genitals. That is unlikely, but, interestingly, one researcher has suggested just the opposite; that de-afference to the feet would result in afference for the relevant neural regions spreading being adopted by the genitals (when a limb or other non-vital body part is lost or the communication of its somatosensory stimuli to the brain interrupted, other regions can adopt the use of "their" part of the homunculus for increased sensory utility or redundancy) leading to women with increased sensation in their genitals who then became prized lovers: [8]. But personally I find that last piece of research highly speculative and I tend to doubt it for a number of reasons relating to biopsychology that are too complex to discuss briefly here. Snow ^{let's rap} 08:12, 1 January 2016 (UTC)

Evolutionary psychology predicts that males, in particular, will be attracted to indications of fertility. It then is only necessary to demonstrate a link between these and feet to explain the male version of this Partialism. Any student of human reproduction knows that the single most obvious factor for female fertility is age, heavily skewed toward youth. Now consider a TDB blog contribution by Tom Sykes dated July 26th 2012:

"I hate to say it, but these snaps prove the point that no-one over the age of 20 should ever allow their feet to be photographed. Even if you're a princess." http://www.thedailybeast.com/articles/2012/07/26/kate-s-feet.html

Also consider the essay by Erma Bombeck dated January 8, 1992 "Even for Scarlett, hands a giveaway" Although feet are never mentioned, the point is that some body parts betray age more severely than others. related topics: Collagen, subcutaneous fat, muscle tone, estrogen levels , lack of melanocytes, capillary health. Evolutionary psychology doesn't have to make sense as long as it works. --Digrpat (talk) 15:43, 31 December 2015 (UTC)

So do faces and arms and necks, which often have a lifetime of exposure to the sun. ←Baseball Bugs ^{What's up, Doc?} carrots→ 02:20, 1 January 2016 (UTC)

True. Erma Bombeck mentions "turkey necks" in that essay and the lack of any procedure or cosmetic to fix them. An attraction to any of these areas will likely not cause a poorer choice of mate selection than might otherwise occur. That is enough to allow such behaviors to persist through the generations. The high percentage of Foot fetishism#Relative frequency suggests that it may serve as a difficult to circumvent pedometer. --Digrpat (talk) 03:27, 1 January 2016 (UTC)

It's easy to propose Just So Stories in evolution, hard to prove them (and worse, hard to disprove them). For example, it is also possible that instead of fertility, the frequent examination of feet by sexual partners meant that thorns, wounds, splinters would all be tended to with great care, or that one partner would try to keep another off her feet to heal if necessary, etc. increasing the odds of successful child-rearing by reducing infection. Of course, that is no easier to prove or disprove. Wnt (talk) 12:55, 1 January 2016 (UTC)