Wikipedia:Reference desk/Archives/Science/2013 November 15

Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

November 15

Using Computers in Space

I asked about using GPS, Iridium and GSM in space. It's quite amusing that our spacemen can hardly enjoy space technologies without using very expensive military grade equipment.

• Radiation hardening

Now what would happen if you send an unshielded modern computer into low earth orbit? Today's ICs are so advanced, material background radiation could easily affect the bits stored in DRAM. Does it mean a computer, unprotected from space radiation, may crash within minutes? -- Toytoy (talk) 04:37, 15 November 2013 (UTC)

Modern semiconductor components employ a wide variety technique to harden against radiation (or rather, single event upset or failures as it could be anything). Keep in mind that background radiation and radiation at elevations as low as 5,000 feet have not changed while device sizes have. Things like triple bit error detection, double bit error correction in memory lines are fairly common algorithms (a 256 bit line in a cache dedicates a certain amount of bits for error correction so reading the line, going through the decoder corrects the error and writes the correct value back so the line is error free again. The ECC bits are no different than the memory bits). Techniques that exist today for the smallest sized transistors can often be sent back a generation as a "hardened" technique. (i.e. parity was an error detection scheme that worked when errors were rare, that was replaced with single bit error correction, double bit detection - now applying the error correction algorythm to feature sizes previously protected with parity is "hardening".). Lead (Pb) used in packaging when BGA and flip-chip started used to be a major ionizing radiation source but it, too, was adapted. So the answer is basically today's ICs run the gamut of hardening. Low-power is also just as much of a concern in satellites so a lot of the tradeoffs is power v. hardening. Also some microprocessors that are advertised with multiple cores also have different modes that are designed to harden them against errors (i.e. a lock-step mode). Think about the radiation as simply a multiple of the radiation at sea level. A Los Alamos massively parallel computer system will have faults generated at random and it is not an insignificant problem and is magnified by simply by being at elevation. It also has to be state of the art. So, it's less about the technology of the components than it is about how the components react together in their environment. Do you use your laptop or iPad on an airplane? That in itself is a large increase in available radiation. --DHeyward (talk) 07:09, 15 November 2013 (UTC)

From our International Space Station article: "The ISS is equipped with approximately 100 IBM and Lenovo ThinkPad model A31 and T61P laptop computers. Each computer is a commercial off-the-shelf purchase which is then modified for safety and operation including updates to connectors, cooling and power to accommodate the station's 28V DC power system and weightless environment. Heat generated by the laptops does not rise, but stagnates surrounding the laptop, so additional forced ventilation is required." Katie R (talk) 12:55, 15 November 2013 (UTC)

The ISS itself is a metal shield. I don't know how thick is the shell. At least it can withstand the 1 ATM air pressure inside the ISS (see International Space Station#Atmospheric control systems). No wonder they have to spend hours in a depressurized chamber breathing pure oxygen before EVA. Life on the ISS is much better than in a space capsule where the air pressure can be very low.

It also explains another question about hard disk. Today's hard disks require air pressure for the disk head to hoover above the disk plates. If the air pressure in the ISS is too low, the computer's hard disks may simply cease to work!

There will be helium-filled hard disks within a year or two. These helium-filled disks will be totally sealed. I guess they may work in space. -- Toytoy (talk) 13:09, 15 November 2013 (UTC)

Solid state drives are a more conventional solution to computers at high altitudes. They're expensive for the everyday consumer, but the cost would be utterly negligible compared to anything else on the ISS. --Bowlhover (talk) 16:25, 15 November 2013 (UTC)

Solid state drives are quite new. Before they were cheap enough, I guess they used specially-made high-altitude hard drives (in case of a loss of air). And life in space can be boring. They need much disk space for them to store Hollywood movies (who gives copyright a damn). I don't think the MPAA can send a lawyer to the ISS to check their disk drives. No wonder their computers are infected with a virus[1]! -- Toytoy (talk) 02:42, 16 November 2013 (UTC)

They weigh less too, so they probably cost less overall when you include what it costs to get them up there. Katie R (talk) 16:45, 15 November 2013 (UTC)

Why m.s-1 instead of m/s?

Why most physics related stuff uses m.s-1 instead of m/s, which is more intuitive and more people use it in everyday lives? — Preceding unsigned comment added by 101.255.36.219 (talk) 11:36, 15 November 2013 (UTC)

(I wrote an answer but I think it might have been incorrect. Please disregard it, sorry!)80.254.147.164 (talk) 12:11, 15 November 2013 (UTC)

s^-1 = 1/s.

As a result, m/s = m ⋅ s^-1.

I think it is a good idea that you use multiplication signs exclusively in a formula instead of using multiplication and division signs here and there. A mixture of two signs may result in more calculation errors. -- Toytoy (talk) 13:16, 15 November 2013 (UTC)

m.s-1 does not mean (m ⋅ s)-1. It means m ⋅s^-1. -- Toytoy (talk) 13:18, 15 November 2013 (UTC)

In everyday use, it seems to me that m/s is far more frequently used than m·s⁻¹, said metres per second (the article does not say anything about this). You could regards the slash notation as being more "intuitive" (really just more familiar to most people, as "per") than the notation for the inverse. In physics and other disciplines, where many combinations of units occurs, use of the raised −1 forms part of a more regular, and hence more more convenient, system of denoting units, where powers are combined with division and parentheses are not necessary, e.g. kg/(m·s²) would be written kg·m⁻¹·s^–2. —Quondum 15:22, 15 November 2013 (UTC)

One possible reason is consistency with other expressions in an article. Lets say an article contained the expression m∙s⁻¹∙cy⁻¹ to make it clear which units were in the denominator of the fraction. The same superscript might be used throughout the article to indicate division. Jc3s5h (talk) 16:00, 15 November 2013 (UTC)

Another issue is publication technology. Nowadays, we can, with some effort, write $m/s$, or ${\frac {m}{s}}$, and likewise m·s^(-1), or $m\cdot s^{-1}$. Not that long ago, many of these forms would require special typesetting when publishing a book, and that cost more money. Also, even though modern journals and book publishers can easily do things like this: ${\frac {\frac {a_{x}}{b_{y}}}{\frac {c^{z}}{d^{w}}}}$, they usually prefer inline forms, because large unwieldy expressions make the whole page look bad (see e.g. right there). There are several technologies supporting all this, including LaTeX, MathJax, Mathml, and many others.

Finally, things like OCR get all messed up on fancy math, and it also looks bad on axes labels for graphs. So, the lesson is, we "pretty print" when it aides understanding of complex expressions, but use old fashioned methods when they suffice. SemanticMantis (talk) 16:14, 15 November 2013 (UTC)

When you start getting more complex equations/units. e.g. acceleration is m.s-2 . Pascal is N.m-2 , Newton is kg.m.s-2 once we start combining units it is easier to add and subtract powers, hence pascal becomes kg.m-1.s-2 i.e. it is making it easier to work with units.Martin451 02:02, 18 November 2013 (UTC)

Is there a scientific explanation as to why gay kids are bullied?

Is there a scientific (psychological/neurological) explanation as to why gay kids are bullied? Is childhood homophobia a social contagion, observational conditioning, social transmission of information, operant conditioning, etc. or all of the above? 140.254.136.168 (talk) 18:00, 15 November 2013 (UTC)

No and yes, and you should read bullying and child sexuality. If you have a specific question you want answered, you can ask it, or check the Ohio State University library. This is not the place for open-ended discussions, especially not when your edit history shows you rarely follow up on the myriad questions you create here. μηδείς (talk) 19:11, 15 November 2013 (UTC)

Medeis, this being the Science desk, a question asking about the existence of a scientific explanation of something seems quite valid. It's not really open-ended. If it drifts off into something other than scientific explanation, it can (and should) be hatted. HiLo48 (talk) 21:23, 15 November 2013 (UTC)

This editor is a troll. He posts endless provocative questions with no obvious interest in the answers. It seems feeding trolls is an addiction around here. μηδείς (talk) 22:35, 15 November 2013 (UTC)

Have you reported the troll? Anyway, I still think this particular question is a reasonable one. Maybe the troll is changing. HiLo48 (talk) 23:28, 15 November 2013 (UTC)

It's an IP-hopper along a particular subnet, so reporting would be futile. They won't do a rangeblock on such a large range, and checkusers won't do anything about IP's. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:38, 15 November 2013 (UTC)

(ec) I don't think there's anything unique about homophobia, as kids are also bullied because of their race, language, weight, appearance (such as wearing glasses), etc. Bullies just look for any difference and use that as a justification for their behavior. I suppose it's a combo of asserting dominance and favoring their own group, which can both have evolutionary advantages. StuRat (talk) 19:13, 15 November 2013 (UTC)

You're onto it. The issue is not really why some particular group is targeted for no apparent reason, but rather why anyone is targeted for no apparent reason. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:41, 15 November 2013 (UTC)

The external links on Kinsey Institute for Research in Sex, Gender, and Reproduction should also help you find some references, or put you in touch with some experts that can help guide your search. Katie R (talk) 19:21, 15 November 2013 (UTC)

I have a theory that linguistic issues are involved in anti-gay feelings among kids today. (Though not the only aspect.) The first meaning of the word gay that children learn is that of being something that someone doesn't like. At a quite young age they will hear someone say "That's gay" or "This school is gay" or similar, long before they have any knowledge of the sexual meaning. So, it's a word with negative connotations from the moment they first hear it. When they discover that it also means homosexual and find out more about what that means, it must be impossible initially to separate the negative connotation from the newly discovered, sexual meaning. HiLo48 (talk) 21:58, 15 November 2013 (UTC)

In my adolescent years, the term "queer" was used exactly the same way. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:39, 15 November 2013 (UTC)

Where I grew up "butch" always meant lacking a perfumed deodorant. The pig farm on the edge of town and the dumpsters behind McDonald's were always called "butch" for that reason. It was hard as an adult for me to accept that spikey haired Lesbians and leather-queens might not necessarily smell bad. μηδείς (talk) 00:23, 16 November 2013 (UTC)

Well, in my childhood in Gloucestershire, we always sang "God Save the Queen", and that made me think I had to pray for the effeminate male patrons when I started frequenting gay bars in my 20's. μηδείς (talk) 00:23, 16 November 2013 (UTC)

Given their frequent targeting for abuse, that was not inappropriate. ←Baseball Bugs ^{What's up, Doc?} carrots→ 02:24, 16 November 2013 (UTC)

"Queer" originally meant "strange" or "not normal". J B S Haldane is famous for the quotation "The universe is not only queerer than we imagine, it is queerer than we can imagine" - and he wasn't referring to its homosexuality! --TammyMoet (talk) 16:42, 16 November 2013 (UTC)

It hasn't stopped meaning that. According to Etymology On Line: "queer (adj.) c.1500, "strange, peculiar, eccentric," from Scottish, perhaps from Low German (Brunswick dialect) queer "oblique, off-center," related to German quer "oblique, perverse, odd," from Old High German twerh "oblique," from PIE root *terkw- "to turn, twist, wind" (see thwart (adv.))" "Sense of "homosexual" first recorded 1922; the noun in this sense is 1935..." Apparently there are actually a few people still alive from the era when the "gay" meaning hadn't yet been published. μηδείς (talk) 20:04, 16 November 2013 (UTC)

Lots of people. The Flintstones theme song from the 1960's said "...we'll have a gay old time !", in the end, and somehow I doubt if they meant it that way. StuRat (talk) 20:35, 16 November 2013 (UTC)

I am unfamiliar with the "queer old time" version. μηδείς (talk) 21:31, 16 November 2013 (UTC)

As a high school teacher, when I hear the word "gay" used by teenagers (with whatever meaning), I often throw in the line "Which of the three meanings of gay do you intend in that sentence?" Forcing them to think about three distinct meanings usually stops any sense of bullying or just plain rudeness that was going on, at least in the short term. HiLo48 (talk) 21:06, 16 November 2013 (UTC)

Yes, I've said something similar in those circumstances. Wiktionary has more than three senses, and my local dialect has another gay (no village jokes please), often spelt "gey", regularly used just for emphasis. ( ... and, Medeis, I can recall first hearing (and being puzzled by, in the 1950s) the word gay used in a sense other than Wiktionary's "dated" senses, then I can recall first hearing the more recent "lame, uncool, stupid" sense. ) This must be one of the mast rapidly changing words in English. Dbfirs 21:32, 16 November 2013 (UTC)

South Park has had fun with some of the different meanings of gay, like the musical group "Getting gay, with kids". StuRat (talk) 22:20, 16 November 2013 (UTC)

The term "gay" meaning "homosexual" has been around for quite a few generations, but it didn't really start to go mainstream until the late 1960s or so. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:21, 16 November 2013 (UTC)

Aside from the "gay old time" in the Flintstones theme, another old-fashioned usage is in "Deck the Halls", with the line "don we now our gay apparel", which I saw parodied in the late 60s in a cartoon panel showing a guy cross-dressing while singing that line. Then there was the line from Bringing Up Baby in a scene where Cary Grant has to don some women's clothing. Someone asks him why he's dressed like that, and he says, "I just went gay all of a sudden!" ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:26, 16 November 2013 (UTC)

Australians can buy a Gaytime. HiLo48 (talk) 04:37, 17 November 2013 (UTC)

My favourite is the song "Girls Were Made to Love and Kiss" from the 1925 operetta Paganini by Franz Lehár, made famous by Richard Tauber. It's indisputably about heterosexual romantic love, yet read how the English words supplied by A. P. Herbert in 1937 go:

• Girls were made to love and kiss / And who am I to interfere with this? ? Is it well? Who can tell? / But I know the good God made them so - so far, so good. Then comes this:
• Am I ashamed to follow Nature's way? / Shall I be blamed if God has made me gay? / Does it pay? Who can say? / I'm a man, and kiss them when I can. It continues:
• Yet I have suffered in Love's great deeps / I know the passion that never sleeps / I know the longing, the wronging of hearts / The hope that flatters and shatters and smarts / I suffer still but I sleep at nights / Man cannot always be on the heights / And now the aching and breaking is done / Flirting is jolly, it's folly, but fun.

After the first verse he seems to have had something else on his mind than girls. I have no idea how true Herbert's translation was to the original German words. -- Jack of Oz ^{[pleasantries]} 07:42, 18 November 2013 (UTC)

This has totally sidetracked, but might as well mention "Oh, Boy! (song)" :) Wnt (talk) 08:10, 18 November 2013 (UTC)

I think the OP would get better results at the Humanities desk, because I get the feeling people here aren't taking bullying as a serious science, whether it could be or not. My assumption is that a certain amount of genuine ideological hostility drives it, but I wouldn't even know where to look to see if anyone has tried to relate the incidence of people in the population openly hateful of a group to the incidence of bullying in schools. My feeling is that bullying is a fundamentally adult phenomenon, no matter how much people associate it with children - that children who bully do so because school authorities are more afraid to go after them than they are to pick on the victim themselves, and that the patterns of bullying therefore largely reflect the social bullying that goes on in the adult community. Wnt (talk) 08:10, 18 November 2013 (UTC)

The question is trolling. Define "scientific explanation". Is he looking for a gene that codes for an anti-gay protein? Define gay. Is he saying football players who sodomize weaklings and threaten them not to tell are gay, and get bullied? Is he saying that effeminate and nerdy kids who seem like easy victims are in inherently different classes? By gay, does he mean boys who get manipedis and summer in Provincetown while snorting amyl nitrate? Does he mean spikey-haired girls who sell advertising for Theater Week? Note the OP lost interest in this thread the moment he posted it. μηδείς (talk) 19:59, 19 November 2013 (UTC)

Capillary electrophoresis

In typical capillary electrophoresis, why does decreasing the pH of the running buffer result in longer retention times? Does it has something to do with electroosmotic flow? --FutureTrillionaire (talk) 18:58, 15 November 2013 (UTC)

I assume so, you only get electroosmotic flow when the capillary wall becomes charged, which happens when the SiOH groups become ionized (SiO^-). Higher pH means more SiOH groups are ionized, so more electroosmotic flow. Lower pH gives less EOF, longer retention times... http://chemwiki.ucdavis.edu/Analytical_Chemistry/Instrumental_Analysis/Capillary_Electrophoresis Ssscienccce (talk) 11:29, 16 November 2013 (UTC)

If the charge of the analyte is pH dependent, that might also be a factor. (+)H₃N-Protein\Chemist-CO₂(-) 17:29, 18 November 2013 (UTC)

Ethology and Behavioral ecology

Dear Wikipedia Hello, My question is simple. What is the difference between Ethology and Behavioral Ecology?

Sincerely, Kooz (talk) 21:09, 15 November 2013 (UTC)

Ethology is animal behavior, while behavioral ecology is why that behavior evolved. StuRat (talk) 05:59, 16 November 2013 (UTC)