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November 7

Close Encounters of Jupiter

I am writing an article about the comet 40P/Väisälä, and one of my references say that the comet will pass 0.09639 AU from Jupiter in 2127. What would such a close approach to Jupiter do to the orbit of this comet? If possible, could I see the equations used so I can calculate orbital perturbations in the future? Thanks, Carbon6 ^talk 04:02, 7 November 2013 (UTC)

First, 0.1 AU is still 15 million kilometers, or ~40 times the distance from the Earth to the Moon. So while it is close, it is not extremely so. Jupiter has ~300 Earth masses, so in sum the gravitational attraction will be be about 5 times less than that between Earth and Moon. Since this is a general n-body problem, there is no closed solution - as far as I know, the analysis of such situations is often done using step-wise iterative simulation, basically applying Newton's law of universal gravitation and his laws of motion, although I wouldn't be surprised if modern models also incorporate secondary effects. --Stephan Schulz (talk) 10:37, 7 November 2013 (UTC)

Looking at Carbon's reference led me here which will calculate the comet's ephemeris at relevant times. However, to what extent the orbital elements will change, I don't know. Thincat (talk) 12:02, 7 November 2013 (UTC)

You can change the ephemeris type in that calculator to elements and get orbital elements to till year 2200... so inclination is expected to change from 11.5 degrees to 9 degrees. Close encounters also act to magnify observational errors on current orbital elements, but I don't think it matters much here. Wait long enough (few Myr?) and everything is chaotic. 88.148.249.186 (talk) 14:01, 7 November 2013 (UTC)

• You need to know how fast the comet will be moving as it approaches Jupiter in order to calculate how much Jupiter will affect it. See http://www.bogan.ca/orbits/gravasst/gravasst.html for a description of the basic calculation. Looie496 (talk) 15:40, 7 November 2013 (UTC)

If that's the case, then it might help to know that the comet is moving at a relative velocity of 10.23916 km/s. What result would that give? Carbon6 ^talk 01:59, 8 November 2013 (UTC)

Digital to analog signal

I have a wire that has a 5v digital signal on it. For an example, think of an HD activity light on a computer. I have an LED on it and it blinks on/off. I want to get a better feel for if it is blinking a lot or a little. My goal is to connect it to an analog panel. I already did that. It pegs at 0 and 25 (the maximum value on the meter) with nothing in between, except that it sweeps from left to right very quickly when pegging from one side to the other. My assumption is that I can place coil or inductor on the line to inhibit the digital change and make it sweep slower. I know the voltage is 5v. I do not know the amps, but it has to be ridiculously small because it only drives an LED. If an inductor is the proper solution, what size? Is there a way to easily adjust the voltage so the meter won't peg hard when it hits 5v? I assume a resistor will do. — Preceding unsigned comment added by 209.149.113.217 (talk) 17:46, 7 November 2013 (UTC)

A resistor and capacitor are commonly used for this sort of situation. Basically, you're trying to filter the square wave coing in into a smoother analog signal. The 5V will slowly charge the capacitor, and the resistor slowly brings it back down. (Slowly being relative - slow compared to the near instant hange of the digital signal) If it is going on and off quickly enough, the simple filter will average it out to a pretty steady voltage somewhere in between. Katie R (talk) 18:18, 7 November 2013 (UTC)

With analogue panel meters, the scale does not necessarily correspond to the full scale deflection (FSD), particulalrly if the meter is second hand or has been removed from equipment. For example, a common FSD is 1 mA; 50 microamp is also common. If the scale is marked 0 to 25, a 1 mA FSD meter may, for example, been used as a 25 volt voltmeter by means of a series resistor of 25 kohm. Or it may have been used as an ammmeter by means of a shunt resistor. You need to do the following steps:-

1 Determine the FSD current of the meter. Remove any shunt resistor. In a good quality panel meter, the FSD current will be marked on the bottom of the scale in an unobtrusive way.

2 Calculate the series resistance required to get the FSD current at 5 V. For a 1 mA FSD meter, you need 5 kohm.

3 Choose two approximately equal standard resistor values that in series make up the calculated value or just slightly greater. Using 5 kohm as the calculated example, choose say 2.4 kohm and 2.7 kohm.

4 Wire the two resistors in series with the meter.

5 Connect an electrolytic capacitor between the mid point of the two resistors and the opposite terminal of the meter. The capacitor should be sized about c = 4000 T/R where c is in microfarads, T is the response time you want in seconds, and R is the total resistance in kohms.

Don't connect a capacitor directly across the terminals of an analog panel meter as you will get an undesirable bouncing of the pointer.

124.178.58.238 (talk) 23:55, 7 November 2013 (UTC)

How fancy? Oversampling and decimation is a very common technique to convert a single bit stream into an analog signal. It's the sampled version of an integrator mentioned above. Basically, when the signal is 5V, each sample puts a fixed charge on the integrator while each 0 subtracts. See Delta-sigma modulation. Or even Pulse-width modulation for ideas. The tradeoff is the switching noise is pushed into the sampling band allowing a LP filter to have a higher cutoff (smaller caps) or keep the same cutoff for more accurate reading. --DHeyward (talk) 08:12, 8 November 2013 (UTC)

November 8

stillborn dog

(Warning, a slightly gruesome question in a veterinary way.) A few decades ago, I had a dog that gave birth to three puppies. The first was twice as large as the other two, which were normal size (she'd had litters before), and the third was not small, but was stillborn. I had to bury it, and the odd thing was it seemed very undeveloped, basically a limbless, faceless bag of fur. Is this a common thing with animals that have litters? Is there any name for this? Thanks. μηδείς (talk) 01:17, 8 November 2013 (UTC)

Runt is the usual term, but our article on the subject is absolutely appalling; I would advise anyone against reading it. This article, although not exactly a model of scientific rigour, concerns runt puppies and actually contains some information (unlike ours). Tevildo (talk) 01:59, 8 November 2013 (UTC)

Yes, but this wasn't a runt in the normal sense. Let me clarify. The first puppy was huge, easily two or three times the mass of any other pup the mom had ever borne. The second puppy was normal in size for her pups and in all other respects. The third puppy was dead, and perhaps even a little bigger than the second puppy, but basically just a sack of fur. (The mother was a blonde Shepherd, the father a Black Lab, the living puppies black, and the stillborn puppy chocolate brown, in case that's relevant.) She had partially buried it in her doghouse, and it was only when I went to remove it (and to take her and the living puppies indoors) that I realized it wasn't afterbirth. (Unless maybe there is some sort of skin that actually forms around placenta in some cases?) I am very familiar with normal runts, which are small and sometimes deformed, but this was just odd, as if it had never developed a solid skeleton. I can certainly accept that might be some sort of wierd uncommon mutation, but I am wondering if it is some other sort of result of litter births. μηδείς (talk) 02:40, 8 November 2013 (UTC)

This is incredibly speculative, and some would probably say I shouldn't do veterinary diagnosis on the Refdesk (I will state clearly, it should not be used as such!). But my guess is that the ball of fur was a teratoma. There might be some connection between it and the large puppy, as both of them could conceivably have carried a mutation in a proto-oncogene that would allow them to grow bigger and increase tumor risk. (something like KRAS [1] - just an example; I haven't thought over all the possibilities carefully) Wnt (talk) 06:00, 8 November 2013 (UTC)

I would guess that there was a problem with the umbilical cord which should have gone to the stillborn puppy, and it instead went to the huge puppy, which received all the nutrients which should have gone to both. StuRat (talk) 08:47, 8 November 2013 (UTC)

I too suspect there might be something like a teratoma going on, or maybe a mutation in the skelatal system. But this was a separate puppy, not a tumor of one of the other pupies, with a different fur color, and weighed probably 3/4 of a pound. It must have had a working umbilical connection or it would have aborted at a much smaller size. Like I said, the normal puppy was slightly smaller than the dead puppy, while the huge puppy probably weighed at least a pound and a half. The two living puppies maintained that difference in size through maturity, with the same proportions, but the large one weighing twice as much as the small one. μηδείς (talk) 17:02, 8 November 2013 (UTC)

Teratomas can occur in the placenta or umbilical cord (it's uncommon in humans, but I'm not so sure about dogs) Wnt (talk) 03:38, 9 November 2013 (UTC)

Twin-to-twin transfusion syndrome would align with the idea of one abnormally large compared to one nearly un-grown. But if the fur colors are noticeably different, they don't sound monozygotic. The whole idea of "received all the nutrients which should have gone to both" sounds like it would be limited to "both" being supplied by the same placenta. DMacks (talk) 05:14, 9 November 2013 (UTC)

Perhaps it had a canine version of hypophosphatasia -- apparently humans born with it can appear to be boneless[2]. 88.148.249.186 (talk) 17:23, 8 November 2013 (UTC)

Yes. My first hypothesis was that this was not something rare or special. But if it's not common in litter-bearing animals, some sort of bone-forming malady was my default assumption. Thanks for the link. μηδείς (talk) 02:49, 9 November 2013 (UTC)

Without looking at the more complex side of things, could this simply be an uneven separation of the fertilized ovum? One part larger than the other, resulting in the huge puppy and the stillbirth? I would imagine it does happen. If it doesn't, ignore me. 80.4.147.13 (talk) 11:42, 9 November 2013 (UTC)

That would have resulted in identical twins, but they were different colors. The very early embryo could have split unequally, but the size difference would have disappeared over time as the fetuses were fed by the uterus. μηδείς (talk) 17:45, 9 November 2013 (UTC)

Brownish spike-like object in my shoe

I was out walking in gravel/grass today. When I got home, I noticed a light-brown spikey/spiny object stuck to my sock. It was very hard to pull off, and even with folded toilet paper between it and my hand, I was poked by it and bled a little. Does this spikey object have a name? How did it get it my shoe (which is extremely tight), and how did it get all the way down to the tips of my toes and stay there until I took it off without me noticing? -- Tohler (talk) 01:37, 8 November 2013 (UTC)

You haven't given sufficient information. A picture would be good. What country/locality are you in? If you are in Australia, or Africa, or perhaps the USA, it could be a douuble-gee or related species. See Wikipedia article on Emex Australis. Nasty things, particularly for dogs. Some variations have barbs. 124.178.58.238 (talk) 01:51, 8 November 2013 (UTC)

Apologies; I'm in southeast Arizona, United States. I have no picture since I threw it away and flushed it (I was in the bathroom when I noticed it). -- Tohler (talk) 01:55, 8 November 2013 (UTC)

I'm thinking bur. Wnt (talk) 02:00, 8 November 2013 (UTC)

(edit conflict) The general class of these things is a bur. I'm not sure which bur you've found. There's hundreds. Where I grew up in New Hampshire, we had similar burs that would get stuck on our clothes all the time when we played in the woods. Where I live now in North Carolina, there aren't as many plants that have burs, excepting maybe the sweetgum. --Jayron32 02:03, 8 November 2013 (UTC)

See Ragweed. Ask a local dog groomer about them. They're not like a cactus needle in the skin but when the get into the dog fur, the fur is usually cut to remove it. They can get between their toes as well. Usually a dog that wonders into the desert gets them in their coat so groomers deal with it a lot. --DHeyward (talk) 08:29, 8 November 2013 (UTC)

With regards to your last question, I've noticed that, while even the tiniest bump or crease may be noticeable on the sole of your foot, it's also quite possible to have stuff stuck there, unnoticed, for quite some time. An individual bur, for example, may lie quietly for some time and then a twist of your sock or a shift of your balance suddenly gets you to thinking there's a rogue balrog in your shoe. To put it more simply, if burs were instantly and constantly annoying, they wouldn't be doing their job very well at all. It could be you picked this thing up while in your stocking feet (say, in the arch between the ball of your foot and your toes) and only noticed it much later. Matt Deres (talk) 15:49, 9 November 2013 (UTC)

Physical contact in platonic friendships

Is there any scientific evidence to suggest that physical contact stengthens platonic friendships regardless of gender? Is it dependent on the person? 82.132.225.228 (talk) 08:43, 8 November 2013 (UTC)

Yes, plenty. I suggest you take a look at Haptic communication and the many links and references you will find there.--Shantavira|^{feed me} 13:34, 8 November 2013 (UTC)

Thanks. The article doesn't really talk about strengths of friendships in relation to this though. It focuses more on romantic or sexual relationships. 194.66.246.118 (talk) 14:42, 8 November 2013 (UTC)

I recall several articles about how members of the US government touch each other much more frequently than "normal" people (sadly, I can't find a reference to that right now) - and that there is some kind of indication of rank and allegiances from the way this happens. You can certainly see it in video where they'll frequently touch each other on the shoulder or something. I presume they do this to strengthen their political ties - which would certainly be a case of using body contact to promote platonic friendships - and mostly between people of the same gender. Obviously it is dependent on the person. People (like me) with Aspergers syndrome frequently find body contact unpleasant, except in the most intimate situations. I really hate being hugged, clapped on the shoulder or shaking hands with people of either sex that I don't know extremely well. I'm sure such minor revulsions are not uncommon. SteveBaker (talk) 15:33, 8 November 2013 (UTC)

Are you suggesting that "members of the US government" and "normal people" are two separate entities? ~E

Reminds me of how I often hear ads say "This testimonial is from a real person, not an actor !". This makes me wonder if all actors are really like Max Headroom. StuRat (talk) 21:14, 8 November 2013 (UTC)

He probably meant "everyday" people, although he might be making a point. :) As regards actors, one way to say it might be, "I'm not a real person, but I play one on TV." ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:26, 8 November 2013 (UTC)

• Welcome physical contact releases oxytocin, the effects of which are largely beneficial physically and psychologically. I am not sure if one would describe holding children and pets as platonic per se, but it is great non-sexual experience for most people. μηδείς (talk) 18:17, 8 November 2013 (UTC)

The extent of engaging in touchy-feely stuff requires "knowing your audience". Everyone has a "space" around them that they might or might not like having invaded. I don't think you need to be an Aspie to cringe when someone invades your space. ←Baseball Bugs ^{What's up, Doc?} carrots→ 19:47, 8 November 2013 (UTC)

You might look into non-verbal communication. I recall being taught that even a subtle touch during a sales situation can be favorable (e.g. while passing change) -- and subconsciously prompts a more positive review of the person. Presumably this was based on one or more studies (no clue where to find it, though). ~E:71.20.250.51 (talk) 20:19, 8 November 2013 (UTC)

A strategy like that could severely backfire if the target doesn't like being touched by strangers. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:09, 8 November 2013 (UTC)

Hehehe. μηδείς (talk) 23:13, 8 November 2013 (UTC)

November 9

What is the climate of Moose Factory, Canada?

My friend has an old atlas which says the climate is "TEMPERATE". Since it doesn't say on the Moose Factorypage, what it its climate?Puntaalpo (talk) 00:19, 9 November 2013 (UTC)

According to Temperate climate, the southern part of the area around Hudson Bay, where Moose Factory is located, qualifies as Temperate. ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:30, 9 November 2013 (UTC)

Moosonee, the nearest sizeable town, has a climate described in our article as "borderline subarctic/humid continental". Tevildo (talk) 00:39, 9 November 2013 (UTC)

I've done some additional reading up on the issue, and this climate is described as "Temperate Continental" in the Trewartha climate classification scheme. Tevildo (talk) 00:50, 9 November 2013 (UTC)

Moosonee with a record high of 100F, and a record low of -52F might be better described as "intemperate". Rmhermen (talk) 18:36, 9 November 2013 (UTC)

Alloy Phase Diagrams?

Hello, I was wondering if there is a phase diagram archive. I know specific phase diagrams exist, but is there a page that has a catalog of alloy binary phase diagrams? Is this too technical for general browsing? I know that these help me visualize how different metals interact.

I was also unclear as to the publishing rules for phase diagrams. I don't know that if I had access to a pay to download paper with a phase diagram if I could cite and place it on the website. How could these make it on? Using another person's work may be out of the question, but could an individual create their own phase diagram through experiment to produce these?

Wondering how best to help add some materials science knowledge

Thanks Timmahlaw (talk) 00:36, 9 November 2013 (UTC)

I know that both my local universities have books of phases diagrams in their science library reference section. Hundreds of phase diagrams in each one. I recall one book that has the diagrams in stereo pairs, with suitable bi-colour spectacles tucked into a pocket in the back of the book. I cannot remember the names of the books, but if one uni library has them, presumably they all do, providing they offer good engineering/science/metallurgy courses. By knowing only a very few critical parameters, you can draw your own. For instance, for tin-lead alloy, you only need the melting point of pure tin, the melting point of pure lead, the eutectic point (temperature and tin/lead ratio), and the corner points, you can draw your own. And if you draw your own, there cannot be any copyright issues. Note that for any alloy more complex than 3 constituents, phase diagrams loose their value, as they become multidimensional and impossible to visualise. A bit like phase diagrams for electrical systems - teachers love phase diagrams because they show what happens in a simple circuit containing just one each of R, C, and L, but for real systems they are useless, and only matrix equations will do the job. 124.178.58.238 (talk) 00:54, 9 November 2013 (UTC)

NFPA 704: All three = 4?

Is there any single chemical that has 4's in all three sections of the NFPA 704? Trinitrotoluene only gets a 2-4-4.Naraht (talk) 01:50, 9 November 2013 (UTC)

tert-Butyl hydroperoxide is the usual example. It's often described as the only one among chemicals that actually get rated (commercial or publicly handled when pure rather than just in-lab use). DMacks (talk) 05:06, 9 November 2013 (UTC)

Thank you.

Were there fat cavemen?

Venus of Willendorf

I ran across an exhaustive web ad for some diet plan that claimed "there were no fat cavemen!" [3]. And that just made my ears prick up. How would you know one way or another? --209.203.125.162 (talk) 01:53, 9 November 2013 (UTC)

That's not "an exhaustive web ad". It's just plain exhausting. I gave up after a minute or so. How long does it actually last? But most importantly, it's an ad, and a diet ad at that. Probably the worst possible source for honest information on diet. HiLo48 (talk) 02:01, 9 November 2013 (UTC)

Pre-agriculture, the life expectancy of hunter-gatherers was around 23, so it wouldn't surprise me if obesity incidence was in the low single digit percentages, but the heiarchical nature of how labor is distributed in nomadic tribal societies suggests that it would probably still exist. 114.94.26.72 (talk) 02:22, 9 November 2013 (UTC)

Keep in mind that a life expectancy of 23 doesn't mean most people died at 23. It means an awful lot of babies died more or less immediately, and young children of childhood diseases. Once you made it past childhood you had a decent chance of seeing your threescore and ten. --Trovatore (talk) 02:26, 9 November 2013 (UTC)

In that case, wouldn't the mode life expectancy be a more appropriate statistic? Plasmic Physics (talk) 04:00, 9 November 2013 (UTC)

Are there any animals from those times that would have liked "fatter and tastier"? ←Baseball Bugs ^{What's up, Doc?} carrots→ 04:41, 9 November 2013 (UTC)

• Yes (pictured). μηδείς (talk) 02:46, 9 November 2013 (UTC)

• That doesn't seem like a real person, more of a fertility idol. And, setting "fat" as an ideal makes it seem likely that they were mostly skin and bones. Of course, for them to know what a fat person looks like, there must have been some. StuRat (talk) 04:51, 9 November 2013 (UTC)

Illustration from our article on steatopygia

Yeah, you are right, Stu. Cavemen had never seen fat people, just statues of fat people. μηδείς (talk) 04:54, 9 November 2013 (UTC)

That's the exact opposite of what I just said. StuRat (talk) 04:57, 9 November 2013 (UTC)

Whatever the exact unopposite of what you just said is, you said it looked like an idol, not a person. A little worship carving is the exact definition of an idol. I didn't think it was necesssary to specify it wasn't a fossil. The bottom line is, the OP can look at the image and need look no further. μηδείς (talk) 05:00, 9 November 2013 (UTC)

Obviously it's not a fossil. What I said is that it's not a representation of any real person (the lack of a face is a clue there), but rather of an "ideal". The Terracotta Army is an example where sculptures do seem to be representative of real people, each with unique features. StuRat (talk) 05:06, 9 November 2013 (UTC)

When Stu said, and I quote, "for them to know what a fat person looks like, there must have been some", I'm pretty sure he meant "for them to know what a fat person looks like, there must have been some". I could be mistaken, but that's how I read his statement. Which again, Medeis, is not in any way what you accused him of saying. Which is odd, since, he plainly said exactly what you said he didn't. --Jayron32 05:09, 9 November 2013 (UTC)

The point is the body is an accurate representation of a very obese and probably lactating woman. The lack of limbs seems partially due to damage, and possibly due to the difficulty in working arms on a small figurine. The head is speculated to be covered in a headdress. This seems to be based on a real-life model, not one of a long line of distorted copies or "ideals" such as an anatomically impossible barbie doll. If the headdress theory seems unlikely, look at these pictures of surviving Pagan traditions in Europe, alone. Costumes and headdress in primitive societies are extremely diverse and ingenious. μηδείς (talk) 17:42, 9 November 2013 (UTC)

In world were most people were like Mo Farah, most of today's normal weight fit people would be considered to be unfit obese couch potatoes. Count Iblis (talk) 18:01, 9 November 2013 (UTC)

The obese people of today would probably not be recognised as real human beings. People in prehistoric times lived in a World where there were other species of hominids around, an obese person today would look as different from them as a Neaderthaler did. Count Iblis (talk) 18:17, 9 November 2013 (UTC)

Ridiculous speculation. Hunter-gatherers spent less time, on average, engaging in "work" than modern people (see Original affluent society and Hunter-gatherer) and had at least as much leisure time as we do. The concept that they were emaciated wrecks on the edge of starvation is mostly due to modern H-G's only living on the very edges of livable land, having been forced out there by people employing pastoralism or agriculture. The dudes here, for example, are pretty clearly not in danger of starving to death. Matt Deres (talk) 20:03, 9 November 2013 (UTC)

Not emaciated wrecks, but fit and healthy. It's fair to say that the modern Western view of a fit person was until quite recently biased in favor of declaring overweight people healthy. Bushmen in Africa need to be fit enough to chase antilopes to exhaustion in the 40 C midday heat. Count Iblis (talk) 01:59, 10 November 2013 (UTC)

Funny you mention Bushmen. Read our article on steatopygia which specifically mentions the Bushmen, and the Venus of Willendorf (which it shows from the side--apparently her arms are folded around her breasts and visible from the side). Once again, heavy fertile women were seen as normal and desirable among stone age people. Amazing how differnt the facts can be from our expectations. μηδείς (talk) 18:20, 10 November 2013 (UTC)

So other than cultural artifacts, there is no way to determine from skeletal remains if there were fat cave people? Any XL-sized clothing would have disintegrated between now and then, right? And there's no way to determine how much adipose tissue was on a skeleton? --209.203.125.162 (talk) 19:43, 11 November 2013 (UTC)

Cryonic suspension and damage from radionuclides

How much damage would naturally occurring radionuclides do to a human body which is otherwise well preserved in cryonic suspension? If the human body repairs such damage naturally, how much time would someone have to spend in and then out of suspension for a, say, 50,000 year suspension period? 114.94.26.72 (talk) 02:17, 9 November 2013 (UTC)

I'm not entirely sure the experiment has been done yet... --Jayron32 02:24, 9 November 2013 (UTC)

The question is irrelevant becasue cryonic suspension is nothing more than a big scam. It is not known how to bring a mamillian body down to cryonic temperatures without doing physical damage, and the damege to the brain in particular is not reversible. That is why cryonic suspension is illegal unless the person is already legally certifiably dead - and that alone means irreversible brain damage. Those who believe in cryonic preservation often recognise that the process causes damage in adition to the process of death, but somehow think that all they have to do is keep the body cold long enough for science to figure out how to reverse the damage. That's logically like saying I've accidentally reduced my digital photo to a smaller file size and resolution, but probably some boffin can tell me how to increase the resolution again. It doesn't matter what developments in science might occur - you can't replace information that has been thrown away. Cryonic suspension is just an expensive alternative to sticking the dearly departed in a coffin and burying him/her, or despatching them to the crematorium. 124.178.58.238 (talk) 02:57, 9 November 2013 (UTC)

Except, Cells Alive System freezers which effectively perform vitrification are under a decade old and proven to work for periodontal ligament organ preservation for transplants. 114.94.26.72 (talk) 03:35, 9 November 2013 (UTC)

As ratbone (or wickwack or whatever the IP likes to call himself now) said above, we don't know - the experiment has not and cannot be done. The closest we can get is to look at animals or other organisms that can survive being frozen or otherwise "suspended". The wood frog and some other lower vertebrates can survive being frozen for months at a time, so that's certainly doable. There are frozen worms of Caenorhabditis elegans that are getting on 40 years old and survive well enough when thawed out. The water-bear is claimed survive centuries while frozen. There's difficulty extrapolating that to humans, however. A worm like elegans or a mite like the water bear has far fewer cells than we do. Thus, you are more likely to find a frozen worm or mite that has enough cells survive so that it can function, than you will a human, I bet. Going even smaller, there are frozen human cell lines even older than that, and there are claims of endospores surviving tens of millions of years before being revived, but I'm kind of suspicious. Even in organisms that we can get to survive freezing at all, we don't really know what causes viability to drop with time frozen - it may not have anything to do with radiation or mutations. Those are certainly bad for you, but they may not be what causes the most decay of your frozen body. Perhaps proteins or RNA break down spontaneously so that the cells can't recover upon thawing. So yeah, we don't know, and we can't know, but I wouldn't be surprised if some scientists had posited guesses. Someguy1221 (talk) 03:44, 9 November 2013 (UTC)

I am the person who posted an answer above. I have not given myself any name at all, as unregistered names seem to attract nutters. Nor have I used the names ratbone or wickwack in the past. Why do you refer to me as "ratbone"? 58.169.239.51 (talk) 05:30, 9 November 2013 (UTC)

Putting aside the biotechnical problems of cryonic suspension and assuming that you can freeze the biological structures so that they don't fall apart due to the chemical reactions that still take place, then you can easily estimate the effects of radioactivity. According to our Background radiation article, you would be subject to 0.48 mSv/year due to natural radioactivity from the environment and 0.39 mSv/year from cosmic radiation, so that is 0.87 mSv/year in total. This radiation damage will then accumulate as it won't be repaired. After about 5700 years you'll have accumulated about 5 Sv, which is the accute lethal dose. Count Iblis (talk) 16:06, 9 November 2013 (UTC)

Thank you. Related questions: Is the amount of damage that can be done to frozen tissue by radiation proportional to its temperature? How much does smoking tobacco, smoking cannabis, and breathing coal dust contribute to the incorporation of radionuclides? 210.13.83.18 (talk) 15:27, 11 November 2013 (UTC)

Mainstream scientist

Trolling
The following discussion has been closed. Please do not modify it.
Is Richard Lynn, Rushton, Jensen and Charles Murray considered mainstream scientists, what about their theories? — Preceding unsigned comment added by 174.88.155.12 (talk) 05:21, 9 November 2013 (UTC) For reference: Richard Lynn, J. Philippe Rushton, Arthur Jensen and Charles Murray (author) The mainstream consensus is that there is no link between Race and intelligence. Indeed, the whole concept of race is invalid. The people you mention are or were academics (except possibly Murray; I don't consider a "political scientist" to be a scientist), who presumably contributed much within their fields, but their beliefs on this subject are not accepted by most of their peers. Of course, there's no one single authority that determines what is mainstream and what isn't. Rojomoke (talk) 09:33, 9 November 2013 (UTC) Not mainstream but scientists okay which is more than can be said of most of the climate change skeptics. The problem with intelligence is that it is a far more emotive and bigotry ridden subject than climate change and and very difficult to get decent figures for when you consider the various confounding factors never mind trying to ascribe causes. When we start getting some sort of consensus among economists then perhaps intelligence can be tackled properly next. At the moment we can just about measure some things like IQ or GNP - but do we really know what such figures for intelligence or gross national product really mean? Dmcq (talk) 15:12, 9 November 2013 (UTC) Anyone who tries to characterize the "intelligence" of races is automatically wrong. Intelligence is not in races, it's in individuals. ←Baseball Bugs What's up, Doc? carrots→ 18:00, 9 November 2013 (UTC) Bugs, I don't think that's a valid statement. That's like saying anyone who tries to characterize the average height of women and of men is automatically wrong. In this case, the problem lies in the determination of race and of intelligence (or indeed defining them, and then in measuring them). We need to guard against both the bigoted perspective and the blank slate perspective in something such as this, as it tends to be quite emotively charged and even respected scientists can become less than objective on the matter. Mainstream opinion can and not infrequently does remain heavily biased on such issues for ages. In the current era, my impression is a distinct mainstream bias towards "politically correct" perspectives. Add to this that most studies have nothing to work with except current populations, which are the antithesis of controlled experiments, and are notoriously difficult to control for. — Quondum 18:39, 9 November 2013 (UTC) Could you please elaborate, Quondum? Thanks. — Preceding unsigned comment added by 174.88.241.133 (talk) 20:47, 9 November 2013 (UTC) I'll assume you are asking about my comment on biases. Ideas such as the blank slate originate from an politically correct ideal, and not from observation, and catch on for a while because of social bias, and it can be difficult for others to oppose an idea like this publicly. This can lead to a polarizing pressure, which leads to ideas such as a biological basis for differences in social roles, aptitudes and behaviour in men and women being resisted (or at least not publicly endorsed) by as many scientists. In the case of racially linked intelligence, there are clearly biasing factors present, which means that one should consider these before just accepting any opinion. However, even considering possible biases, the lack of any adequate definition of race in humans seems to render the whole question of anything linked to it moot. — Quondum 22:01, 9 November 2013 (UTC) I agree, political correctness has affected the work on this a great deal, and no wonder good scientists like Rushton, Lynn or Steve Sailer are demonized for not towing the party line. But race can still be found in our genes, because genetic variation is found by continent, so you have negroid from Africa and caucasoid from Europe and stuff like that. — Preceding unsigned comment added by 174.88.241.133 (talk) 22:07, 9 November 2013 (UTC) No, genetic variance in humans is clinal; the concept of "race" is largely influenced by historical patterns of population movement and mass migrations of a narrow number of people groups, and not in actual genetic distinctions between people. Americans, for example, have a view of "race" that is largely influence by the fact that most of the people who Americans have experience with come from, historically, only a few places: West Africa, East Asia, Northwest Europe, and Mexico/Central America. That's why Americans tend to think of the world in terms of "Black/Brown/White/Yellow". But when you look at it from a worldwide perspective, people groups vary gradually and clinally from place to place (and multidimensionally) and the world simply does not fit into the "negroid/caucasoid/mongoloid" baloney. Anyone who thinks in such terms has such a malformed understanding of genetics that they might as well be arguing for the existance of phlogiston or humorism or of a flat earth. SO, people who make such arguments have automatically removed themselves from the mainstream just as someone who was adamantly arguing that heat was caused by phlogiston. --Jayron32 22:30, 9 November 2013 (UTC) Reconsider the question in this way: if an anonymous questioner came by asking for several titles of great introductory books by excellent, well-established authors on the subject of sociology and anthropology, would any of the OP's authors rise to the top of the list? I think the answer is "probably not." If an anonymous questioner came by asking for the most influential recent academic publications in the fields of sociology and anthropology, would these authors rise to the top of the list? I think the answer is "probably not." If an anonymous questioner came by asking for links to the websites of the most widely-respected anthropologists and sociologists - individuals or organizations, would these authors' websites, or the websites of the organizations they represent, be on the list? I think the answer is "probably not." It is only when you dive deep into the study of a specialist sub-discipline that such authors are even relevant, let alone the question of whether their work is well-respected by other experts. So I don't think we can consider these authors "mainstream." "Mainstream" authors will have written textbooks that are read by a sizeable percentage of students and researchers in the field. Mainstream academics are those who present highlight speeches at national and international tier conferences. We can help you find those sorts of authors and researchers, if that's your interest. For example, here is the website for the American Association of Physical Anthropologists. Their front-page lists five news stories that are considered "hot topics" by mainstream experts in this field. Here is a list of books that the AAPA considers "mainstream," and I would posit that they are requisite reading for anyone who intends to seriously study the topic of race and society: Biological Variation in Health and Illness: Race, Age, and Sex Differences by Theresa Overfield (1985) Addison Wesley Publishing Co., Menlo Park, CA. Bones of Contention: Controversies in the Search for Human Origins by Roger Lewin, Simon Schuster, New York. Braindance by Dean Falk (1992) Henry Holt & Co., New York. Gorillas in the Mist by Dian Fossey (1983) Houghton Mifflin, Boston. Human Ecology: The Story of Our Place in Nature from Prehistory to the Present by Bernard Campbell (1983) Aldine Publishing Co., New York. Lucy: The Beginning of Humankind by Donald Johanson and Maitland Edey (1981) Simon & Schuster, New York. Origins Reconsidered: In Search of What Makes Us Human by Richard E. Leakey and Roger Lewin (1992) Doubleday, New York. Through a Window: My Thirty Years with the Chimpanzees of Gombe by Jane Goodall (1990) Houghton Mifflin, Boston. "Often there are articles related to biological anthropology in the magazines Natural History, Discover, and Scientific American." So there you have it: a list of mainstream experts, and the books they have written. Of these, I have read Jane Goodall's book, and Dian Fossey's ancillary; I have read some papers from Leakey. They are entertaining and informative. But I am not an anthropologist. I expect that if you want to be taken seriously, you should read these authors, and many many more, to establish a baseline understanding of the mainstream field, before you undertake an investigation into a more complex and controversial subject. Nimur (talk) 22:43, 9 November 2013 (UTC) The Toronto-based OP is a race-baiting, IP-hopping troll who has already had two of his socks blocked in the last day or so, and the one y'all are currently responding to will be the next one. I've asked (again) for this page to be semi'd, to prevent that bigot from posting here again. ←Baseball Bugs What's up, Doc? carrots→ 22:47, 9 November 2013 (UTC) To be perfectly frank, I don't very much care what the OP's intentions were. As a result of this question, we've had the opportunity to encourage a proliferation of knowledge. The OP is not the only person who reads these responses. Nimur (talk) 22:51, 9 November 2013 (UTC) Well, Frank, the question has been asked and answered countless times, including several times by this particular IP subnet in the last 24 hours. It adds nothing to our body of knowledge here about IQ in general, though it does raise questions about the IQ of the average Canadian. ←Baseball Bugs What's up, Doc? carrots→ 22:54, 9 November 2013 (UTC) One of the OP's socks went to Medeis' desk and tried to start a "PC" dialogue, and when he found out (somehow) that Medeis is a black female, he pulled back, saying "that's disconcerting". That tells you all you need to know about the OP. (Those edits were revdel'd by an admin, so you'll have to ask the admin if you want verification of what was said.) ←Baseball Bugs What's up, Doc? carrots→ 22:58, 9 November 2013 (UTC)

Toll-like receptor signaling

Please explain the difference between My-D88 vs TRIF-dependent signaling.--74.190.109.171 (talk) 14:32, 9 November 2013 (UTC)

TRIF for spleen; MyD88 for liver. TRIF and MyD88 are both intra-cellular proteins.--98.88.144.218 (talk) 16:10, 10 November 2013 (UTC)

Microbe versus Tumor Immune response

What is the difference between immune responses to microbes versus tumors? Please explain it in technical terms for a biology major.--74.190.109.171 (talk) 14:33, 9 November 2013 (UTC)

Do you mean cancerous tumors ? StuRat (talk) 18:21, 9 November 2013 (UTC)

Yes, and the tumor antigens like PSA secreted by the cancerous tumor cells.--74.190.109.171 (talk) 18:27, 9 November 2013 (UTC)

While this looks like a homework question for a biology-related course to me, and I don't normally respond to enquiries posted without a name, it seems that you may have been mislead by the term PSA (Prostate Specific Antigen). An antigen is a substance that an immune system antibody can bind to, so that the immune system can recognise the substance or its carrier as something abnormal and so to be dealt with. But PSA is a substance normally occurring in both the male and female body, attracts no human antibodies and evokes no immune system response. It is produced in the prostate (males) and vagina (females) as part of a range of substances that protect the sperm from residual urine and assist the sperm to swim and reach an egg cell.

Measuring PSA blood level is of value because in the male ONLY the prostate and cancers derived from the prostate can make it. So PSA increasing may be an indication of prostate growth (especially if the man's sex life has wound down) , and if the prostate has been removed, then a measurable PSA level means that one or more secondary tumours must be in the body somewhere.

The reason PSA is termed an antigen is the way the PSA concentration in the blood is measured. Antibodies from a mouse sensitized to human PSA are added to the blood sample (after blood cells have been removed) and the amount bound is measured. It's done this way as otherwise an extraodinarily complex purification process would be required. PSA is thus not an antigen as far as the source human is concerned, it is an antigen as far as the mouse is concerned.

It is policy not to do homework for you, but we do like to assist where you are stuck. You will get a better response if you show that you have already made an attempt at answering a question of the form "Explain the difference between A and B....", say by describing where you are stuck. Your request for an answer in the correct technical language adds to my suspicion that you just want something you can copy-paste. As your question appears to be homework, I have not answered it directly.

124.178.135.228 (talk) 02:02, 10 November 2013 (UTC)

"But PSA is a substance normally occurring in both the male and female body, attracts no human antibodies" because PSA is a self-antigen. I would say that microbes stimulate CD8+ T cells whereas tumor cells stimulate both CD8+ T cells and CD4+ T cells.--98.88.144.218 (talk) 16:07, 10 November 2013 (UTC)

Hmm. I'm a bit unsure about whether PSA is generally expressed by women. Some women can have severe allergological reactions to the PSA in seminal fluid. See PMID 22653399. Seminal plasma allergy caused by IgE against PSA definately occurs. I would have assumed that these women had been tolerant to PSA if PSA were a protein they expressed. --NorwegianBlue ^talk 20:42, 10 November 2013 (UTC)

PMID 22653399 is not evidence that human females can be alergic to human PSA. See http://aje.oxfordjournals.org/content/162/7/704.long. I did simplify things a bit. There is a degree of confusion in medical circles about just where PSA is produced in the female, but there is no doubt that it is produced. As the citation I gave says, measurement shows that the concentration of PSA in the juices of excited females is not dissimilar to the PSA concentration in male ejaculate (see citation 3rd papa). And until recent years, the medical community had a very poor understanding of how sex works for the female. Indeed the name "PSA" arose because early researchers thought it was prostate-specific. Much like the folk that discovered the BRCA-1 gene thought it was specific to breast cancer (becasue they were looking for breast cancer causes, and didn't look at other cancers), whereas we now know that it is involved in all sorts of cancers. The PSA test was initially used in some jurisdictions with vaginal swabs from the alleged victim to "prove" rape! 124.178.135.228 (talk) 02:21, 11 November 2013 (UTC)

Objects above microwaves

Is it dangerous to put a tray of bread or other object above a microwave oven when it is working?--90.165.119.216 (talk) 20:27, 9 November 2013 (UTC)

No -- the microwave oven is sealed so the microwaves can't escape. 24.23.196.85 (talk) 20:45, 9 November 2013 (UTC)

No, there is no reason that shielding around the top of the oven would be any less effective than that around the sides. HiLo48 (talk) 20:49, 9 November 2013 (UTC)

There's also the matter of letting heat and steam escape. Most models have those vents at the sides, but if a model did have the vents on top, then those vents should not be blocked. StuRat (talk) 20:56, 9 November 2013 (UTC)

I was about to give exactly the same warning as StuRat but go on to say that my wife is always putting stuff there and nothing seems to go wrong. But it's her kitchen. Thincat (talk) 21:02, 9 November 2013 (UTC)

And as for why they might put the vents on the top, a microwave oven to be mounted such that there would be no clearance on the sides and back might have top vents (or perhaps front vents). StuRat (talk) 05:54, 10 November 2013 (UTC)

November 10

Image quality: 16mm versus DVD/Netflix

If one like classic movies of the 1930's through 1950's and has the option of a 16mm sound projector or a high definition flat screen showing DVDs/Netflix/OnDemand and ignoring the higher cost of obtaining 16mm films, and the higher inconvenience of storing films and changing reels, does the high definition win in terms of image quality (resolution, contrast, color saturation), or does the 16mm projection? Edison (talk) 02:54, 10 November 2013 (UTC)

It is possible to buy a digital projector today that will outcompete a film projector from 1950 on every single relevant specification: color accuracy, contrast ratio, optical geometric distortion, acoustic noise, energy consumption, ... Until fairly recently, contrast ratio was probably the only line-item on which a film projector could meaningfully outperform a digital projector.

It is possible to procure a high-definition video stored in a modern digital format that is bit-identical to the source footage. Common video compression schemes yield an output video that is nearly identical to the source video, using lossy compression, but is indistinguishable for most viewers. The bit depth, resolution, and frame rate of modern digital video systems effectively oversample images compared to the capabilities of 16mm film, so there should be no relevant information loss due to quantization from the analog format - neither in spatial resolution, nor in the gamut of each digitized pixel compared to the gamut of the optical film. Ken Rockwell has an article on digitized equivalent resolution for several types of photographic film, and the tradeoffs involved. Motion picture film is usually equivalent to a higher ISO film, so there is less reward for digitizing it at very high resolutions.

A video needs to be processed and converted professionally (or at least by a skilled non-professional) to make sure that the digitization does actually preserve all the information that is possible to be preserved. It is very easy to foul up the procedure, and result in digital video that is lower quality than its analog source. Nimur (talk) 04:05, 10 November 2013 (UTC)

Momentum vs kinetic energy

If you apply the kinetic energy formulas you will calculate that (for example) a 6 kg projectile with a speed of 1800 m/s has kinetic energy of 10 Megajoules, enough to lift 1000 tonnes 1 meters high. But if you apply the momentum formula you will rescue that in the same conditions the projectile has a momentum of 10800 Ns enough to give 1000 tonnes only a 1/100 m/s speed, that is less than 1 mm elevation. What is the right formula (what would happen in real world)? 79.49.236.203 (talk) 03:39, 10 November 2013 (UTC)

You have conservation of energy and momentum, which means that the total momentum and energy of an isolated system will remain the same. If a body collides with another body then you need to consider the system comprising of both bodies as that is then an isolated system. If a 6 kg body collides with a much heavier 1000 ton body, then the kinetic eenrgy of the light 6 kg body will be approximately conserved. This is because kinetic energy equals p^2/(2m) and by conservation of momentum the heavy body will get a momentum of order of the ligher body, it's huge mass means that it's kinetic energy can be ignored. So, the lighter body's kinetic energy is conserved, which means that it will change direction. The heavy body will thus get twice the momentum of the ligher body. Count Iblis (talk) 04:17, 10 November 2013 (UTC)

I think the vector relationship makes the worst cast transfer of momentum to be twice the momentum of the original. (i.e ball hits wall orthogonal to it's face and the return direction is 180 degrees). Any impact at an angle will impart less momentum. This is easy to visualize as the limit of the impact angle gets shallower, there is the parallel limit where no energy or momentum is transferred - i.e. no collision). --DHeyward (talk) 06:11, 11 November 2013 (UTC)

The mistake you made, 79, is assuming that all of the kinetic energy of projectile will become kinetic energy or gravitational potential energy of the 1000 tonne object. This can never be assumed - you never know a priori where the kinetic energy is going to go. Much of it could wind up as heat, for instance. Accurately predicting the outcome of a collision based on momentum calculations requires only knowledge of what type of collision is occurring (elastic versus inelastic, and knowing that there is no splintering of objects helps). Someguy1221 (talk) 06:42, 10 November 2013 (UTC)

I assume this a collision? Momentum is always conserved and is a vector quantity. So you can calculate it two ways:

• the first way is as an elastic equation where the 6 kg projectile collides and bounces off the larger one. The vector sums of momentum before and after must be equal. It's elastic so the sum of kinetic energies before and after are equal. The 2 simultaneous equations to solve are $\,\!m_{1}{\vec {u}}_{1}+m_{2}{\vec {u}}_{2}=m_{1}{\vec {v}}_{1}+m_{2}{\vec {v}}_{2}$ and $\,\!m_{1}u_{1}^{2}+m_{2}u_{2}^{2}=m_{1}v_{1}^{2}+m_{2}v_{2}^{2}$. You know $\,\!m_{1},{\vec {u}}_{1},m_{2},{\vec {u}}_{2}$ so need to solve the simultaneous equation for $\,\!{\vec {v}}_{1},{\vec {v}}_{2}$.
• In the inelastic case, the smaller projectile sticks to the larger body and the equations to solve are $\,\!m_{1}{\vec {u}}_{1}+m_{2}{\vec {u}}_{2}=(m_{1}+m_{2}){\vec {v}}_{f}$. You solve directly for ${\vec {v}}_{f}$. After that, there will be a difference in kinetic energy. $\,\!{\frac {m_{1}u_{1}^{2}+m_{2}u_{2}^{2}-(m_{1}+m_{2})v_{f}^{2}}{2}}=lost\ kinetic\ energy$. (someone should check this, it's been a while). --DHeyward (talk) 10:32, 10 November 2013 (UTC)

I was assuming that the collusion is totally elastic and no kinetic energy is lost. I made this question mainly to know if, to know the power of a projectile, must be considered the momentum or the kinetic energy (i.e. a projectile with a speed of 400 m/s has a force twice or four times higher then another with the same mass travelling at 200 m/s?). In the case I made before, even if it's truce that normally the 1000 tonnes object wouldn't be moved, if the decelaration is higher than 1000 g, the force applied is enough to lift that weight. 95.247.218.92 (talk) 15:04, 10 November 2013 (UTC) PS: solving the equation for inelastic case, the solution is a speed of 1/100 m/s for the whole system, the same I gave for momentum. So is the momentum the right solution? — Preceding unsigned comment added by 95.247.218.92 (talk) 15:22, 10 November 2013 (UTC)

No, momentum on its own will not give you the right solution because it does not tell you how the momentum and energy are partitioned after the collision. You need to write down the equations for both kinetic energy and momentum and then solve them simultaneously. I did the maths and found that the projectile would bounce back at well over 1799 m/s. (Obviously this wouldn't happen in the real world because the collision would be highly inelastic. Real bullets are designed not to bounce!) Only 233 joules out of the original 9720000 would be transferred to the target, which is why you got such a small answer for the final speed of the target. --Heron (talk) 16:39, 10 November 2013 (UTC)

Yes, as I explained above, you only need to consider the momentum, as the kinetic energy stays (almost entirely) in the lighter body. While you can solve the equations as the other have explained to you, that may obscure the physics of this issue of why momentum and not energy is relevant here. Count Iblis (talk) 16:54, 10 November 2013 (UTC)

I now see what you mean, Count Iblis, but I'm not sure that the OP has noticed your factor of 2 (it took me a while to catch up). OP, you need to refer to Count Iblis's answer above and note the statement "The heavy body will thus get twice the momentum of the lighter body." If you solve the momentum equation on its own (p = m1v1 + m2v2), as you appeared to be doing in your original question, you will get the answer for an inelastic collision (0.01 m/s). To get the answer for an elastic collision, you need to double the target's momentum, and you will then get the correct answer of 0.02 m/s. The factor of 2 is not exact, but is close enough when the target is much more massive than the projectile. If you are satisfied with the approximation, you can forget about kinetic energy and calculate solely using momentum. --Heron (talk) 18:03, 10 November 2013 (UTC)

A projectile's KE doesn't necessary have to stay with a smaller body though. Modifying the OP's original question with some different assumptions, consider a bowling ball rolled down the lane onto and up a ramp the height of which is just enough to convert the ball's KE to PE. As it comes to a stop, its positioned onto the upper-end of a long lever, which is simply a see-saw that pivots, on which the other end is situated a much a larger and heavier ball. Because the arms of the see-saw are unequal, under the bowling ball's weight the long arm drops as this larger ball gets lifted to an equivalent PE a shorter distance at which point it gets dropped onto another ramp, such that it continues on forward down the lane with the energy of the original ball. Now due to conservation of energy we have the OP's conundrum. The short answer, I think, the system's momentum is still conserved due to Newton's action reaction principle, because if we allowed the larger ball to be propelled out the back of a ship, it produces more thrust (using the same energy) than had we simply thrown the bowling ball and not transferred its energy to the weight. Photons also don't make for very good propellants. Perhaps we can direct the OP to relevant articles. -Modocc (talk) 17:27, 10 November 2013 (UTC)

Yes, this is actually a special case of impedance mismatch casing energy to reflect back instead of being tranmitted to the desired system, and impedance matching to solve this problem. In case of collisions the mass plays the role of the impedance, in electric circuits you of course have the usual electric impedance. In case of sound waves the impedance is related to the speed of sound. If you connect a transmitter to an antenna with the wrong impedance, the power will be reflected back into the transmitter which can damage the transmitter. In that case, you can still use the same antenna, you just have to put an impedance matching device between the transmitter and the antenna. Count Iblis (talk) 18:10, 10 November 2013 (UTC)

The different momentum in this case is explained by a change in the momentum of the lane (and eventually the entire Earth). The idea of the efficacy of different propellants is related to specific impulse. Photons are actually the best propellants if you count by total energy, but the worst if rest mass is free and you count by the amount "added". --Tardis (talk) 02:24, 11 November 2013 (UTC)

To be clear, in an elastic collision, all the kinetic energy that goes in is preserved somehow in kinetic energy going out. Because kinetic energy and momentum are simultaneously conserved, the usual result is that an elastic collision involves a substantial rebound! If you shoot your projectile into a block and it sticks, then it gets the feeble momentum in the projectile transferred to the total mass of block and projectile, and the rest of the KE goes into heat, noise, flying shrapnel, etc. (Well, I guess the shrapnel is elasticity rearing its head; inelastic collisions shouldn't make any shrapnel) The situation where you levitate the block a huge distance is more like if you had a bouncing bullet continually going between the block and the ground banging to push it up, and at the exact moment of collision (only) you released some kind of clamp on the block so that it was in free fall only for that instantaneous moment (since otherwise its PE turns to KE as it falls) Wnt (talk) 20:23, 10 November 2013 (UTC)

Why did lunar module dock with command module on the Apollo program

After leaving the earth orbit on the way to the moon, the command module performed a 180 degree turn and docked with the lunar module. Why was this necessary ? Why wasnt it launched in the correct configuration ? I cant find an explaination anywhere on the internet. I saw this animation on youtube, but no explaination http://www.youtube.com/watch?v=8VvfTY-tVzI Thankyou — Preceding unsigned comment added by Matboyslim (talk • contribs) 20:32, 10 November 2013 (UTC)

The Apollo Command Module was situated forward (above) of the Apollo Service Module. The simplest way to design an egress from the CM was "through the top." An equally valid question is, "why did the CM have two doors?" There are an infinite number of possible design configurations; the astronauts could have been seated anywhere during launch; but at an early stage in the program, this design was selected: the astronauts launched in the foremost compartment, and an orbital rendezvous was required. If you are interested in the very fundamental design tradeoffs that went in to the overall architecture of the Apollo Program, you might enjoy reading NASA's history archive: the Apollo Lunar Surface Journal. There is a chapter on spacecraft design. More specifically, Buzz Aldrin wrote his Ph.D. thesis on why an orbital rendezvous was the best design choice for a manned lunar mission. Nimur (talk) 20:45, 10 November 2013 (UTC)

(ec) The CSM was a separate spacecraft, which was designed to operate independently of the LM (as it did in the Apollo 7 and Apollo 8 missions). There was no need for it to launch in a docked configuration. Perhaps more importantly, launching with the LM docked would have made a mission abort rather more difficult - the CM/CSM would have had to make a 180 degree turn (possibly in the atmosphere) after an abort to get into the correct configuration for re-entry. Tevildo (talk) 20:50, 10 November 2013 (UTC)

Ultimately, the design decision was: given the natural differences between the Earth and the moon; and given the realizable technology available to American humans in the 20th century; two spacecraft were required to deal with the distinct terrestrial and extraterrestrial launch and landing requirements. Therefore, those spacecraft would require at least one rendezvous and docking operation. In Project Apollo, it was decided to use two rendezvous and docking operations. That mission profile allowed astronauts and ground crew to assure that the rendezvous and docking functioned correctly while still in Earth orbit, and to experiment with that operation on pre-Lunar flights (e.g. during the Gemini Program) instead of waiting until the end of the lunar mission to test it. Nimur (talk) 21:04, 10 November 2013 (UTC)

A minor factual correction - TD&E was performed after TLI (although that was technically still in Earth orbit, the actions necessary to go to the moon had been performed). However, I agree that an abort (or fixing a problem with the docking mechanism, as happened on Apollo 14) was much better at that stage than discovering a problem when the LM returned to the CSM from the lunar surface would be. Tevildo (talk) 21:55, 10 November 2013 (UTC)

Correlation between intelligence and sensitivity to the cold?

In humans, is there any correlation between intelligence and sensitivity to the cold? 86.171.42.209 (talk) 20:42, 10 November 2013 (UTC)

That's an interesting question. What makes you think that there might be? It's such an unlikely connection that I doubt whether anyone has done any research on it. There is certainly a correlation between age and sensitivity to the cold, and I'm beginning to wonder whether intelligence decreases with age (especially in my own brain), but remember that Correlation does not imply causation. Dbfirs 20:53, 10 November 2013 (UTC)

I've spent time in both warm and cold climates, and it's really a matter of acclimation to a given area. ←Baseball Bugs ^{What's up, Doc?} carrots→ 20:59, 10 November 2013 (UTC)

I have noticed that there does seem to be some correlation between intelligence and sensitivity to various things like that. Purely personal anecdotal though. Dmcq (talk) 00:05, 11 November 2013 (UTC)

I'm a Mensan and I thrive in cold conditions. Plasmic Physics (talk) 00:14, 11 November 2013 (UTC)

Probably due to our reduced body hair.--Auric talk 00:25, 11 November 2013 (UTC)

Reading around there does seem to be a link between autism and sensitivity to touch and cold and various things like that, and in particular it is a common complaint of those with Asperger's. I guess that might explain my feeling that there is a correlation with intelligence. Dmcq (talk) 00:33, 11 November 2013 (UTC)

And by correlation I don't mean that all or even most of one corresponds with the other. I'm simply saying in a statistical sense. Dmcq (talk) 00:40, 11 November 2013 (UTC)

What a coincidence, not only am I Mensan, who thrives in cold conditions, I'm also an Aspie. Plasmic Physics (talk) 00:53, 11 November 2013 (UTC)

The section in the article Asperger syndrome#Motor and sensory perception seems to indicate the subject has been been studied a bit but there is no general agreement on it. Dmcq (talk) 01:09, 11 November 2013 (UTC)

Are we talking about cold climates like the arctic vs. tropical, or like living in the basement? There are things that people can naturally adapt such as altitude changes will change red blood cell volume, whence the acclimatisation phase of mountaineering summit attempts like Mt. Everest as well as seasonal blood vessel changes -> people take coats off in the spring at lower temps than they put them on in the fall because the amount of blood vessels at the skin surface change to accommodate the need to radiate heat. But I believe Einstein had a wardrobe that consisted of multiple sets of identical clothes so he wouldn't have to clutter his brain with frivolous choices. Therefore, I'm going to say a moderate, unchanging climate without appreciable seasons is best so that coats, sweaters, shorts or pants decision are never necessary. --DHeyward (talk) 07:07, 11 November 2013 (UTC)

I was thinking that under this premise, the Sherpas and the Inuits must be the most intelligent peoples on earth. ←Baseball Bugs ^{What's up, Doc?} carrots→ 13:24, 11 November 2013 (UTC)

Have another go at reading the query. Dmcq (talk) 13:44, 11 November 2013 (UTC)

The OP asked "is there any correlation between intelligence and sensitivity to the cold." Have a go at explaining precisely what the OP meant. ←Baseball Bugs ^{What's up, Doc?} carrots→ 15:35, 11 November 2013 (UTC)

medical condition. Brokers affasier

want to know if this is a correct medical problem.not sure if it is spelt correctly — Preceding unsigned comment added by 5.69.167.5 (talk) 21:08, 10 November 2013 (UTC)

There's an apostrophe missing in "broker's". μηδείς (talk) 21:21, 10 November 2013 (UTC)

The correct condition is "Broca's aphasia", which I see on editing Medeis has also linked, in a less obvious way. - Nunh-huh 21:35, 10 November 2013 (UTC)

Occupational precautions regarding chemotherapy

What does the "Occupational precautions" section of Chemotherapy say? Does it simply say that medical personnel in contact with chemo patients have to be careful lest they end up getting small amounts of the drugs themselves? The wording is complex and hard to follow (I've re-read it several times), and I don't at all understand the ramifications of the first half of the second sentence. Nyttend (talk) 21:48, 10 November 2013 (UTC)

That section of our article contains verbatim excerpts from this CDC website. You have paraphrased it pretty well. Chemotherapy drugs are potentially hazardous. People who handle the drugs need to be careful, avoid direct exposure, and avoid long-term indirect exposure. According to the CDC, exposure to certain anti-cancer chemotherapy drugs can cause everything from skin rashes to causing cancer in healthy people. Antineoplastic drugs are very potent chemicals.

In this instance, I use the phrase "cause cancer" because the CDC expressly states that certain antineoplastic drugs are "known carcinogens." We should be careful to distinguish "known carcinogens" from entities that are suspected to increase risk, or are correlated to cancer incidence in lab studies.

We should also probably re-write the section of this article. Nimur (talk) 21:58, 10 November 2013 (UTC)

Agreed, and what you just wrote above is perfectly clear, so we should change it to say something like that. StuRat (talk) 22:28, 10 November 2013 (UTC)

It was fascinating for me to read this question and its answers, and to look at the CDC material. There are 2 kinds of hospital here in Australia - public and private. Public hospitals are run by the Government and accept "public" patients - that is the cost is carried by the Government. The patients pay nothing. Private hospitals are run by for-profit companies, benelovent foundations, and churches and charge the patients a multitude of fees, which are mostly covered by medical insurance. Public hospitals also accept private patients - that is patients who pay much the same fee as they would in a private hospital, and in return get to choose their doctor(s), avoid waiting in queues and get extra drugs regarded as beneficial but non-essential. When my wife had her first breast cancer, she had chemo as a private patient in a public hospital. The chemo ward nurses wore standard uniforms, and handled syringes, intravenous lines, etc in the normal way. When she had cancer again in the other breast, she opted for a private hopital. The difference in care was very noticeable. One of the differences that stunned us though was that the private hospital chemo nurses, when they went to administer a chemo agent (eg inject it or connect it up to the intravenous drip) they put on, over their standard uniform, a face mask much like the mask that metal worker use to prevent metal filings from entering eyes, nose, etc) a sort of neck-to-ankle apron made of plastic, and gloves. I asked "whats all this?" and the nurse explained that it was standard mandatory safety precautions for her - contact of her eyes, mouth, or even skin with any leak or splash would be regarded as serious. Each time a nurse went from one patient to another, she took off all the safety gear, threw it in a bin, washed her hands, and put new safety gear on. We never saw any of this in the public hospital. 124.178.135.228 (talk) 01:55, 11 November 2013 (UTC)

Unidentified goose (Orange County, CA)

I saw this odd-looking goose at a park in Orange County, California. It's about the size of an Egyptian Goose, and was associating with a gaggle of them. What species/breed is it? 69.111.17.141 (talk) 23:40, 10 November 2013 (UTC)

My browser gives a warning on visiting that site. μηδείς (talk) 23:46, 10 November 2013 (UTC)

Darn, sorry about that. It should be perfectly safe. But in case there's a problem with dropbox, I'll rehost the picture here. 69.111.17.141 (talk) 00:06, 11 November 2013 (UTC)

Thanks for rehosting that. If you search for "grey goose" (you have to use advanced search to exclude "vodka") you will see plenty of grey geese on google images. Indeed, geese of the genus Anser are called the grey geese. But they all seem to have orange bills, not black ones. This may be an example of partial melanism. I suggest going to Wikipedia:WikiProject Birds if you don't get a more . . . black-and-white answer . . . here. μηδείς (talk) 01:16, 11 November 2013 (UTC)

Looks like the Snow Goose, or at least the one pictured here: [4]. StuRat (talk) 01:10, 11 November 2013 (UTC)

Thank you for the feedback-- upon consulting a few different bird guides, I think what I have is an immature Snow Goose. 69.111.17.141 (talk) 01:30, 11 November 2013 (UTC)

Chronic effects of nerve agent exposure - why?

Why are the effects of nerve agent exposure long-lasting and cumulative, when nerve agents act solely by inactivating acetylcholinesterase, and therefore normal transmission of nerve impulses can resume as soon as the inactivated acetylcholinesterase is replaced? Whoop whoop pull up ^{Bitching Betty | Averted crashes} 23:47, 10 November 2013 (UTC)

Can you give a source for this assumption? Which nerve agent(s)? μηδείς (talk) 23:50, 10 November 2013 (UTC)

I suppose (although I'm guessing) that it's not the production of the acetylcholinesterase or the acetylcholinesterase itself that's being "inactivated". It's probably blocking whatever the next step in the biochemical pathway is - and thereby preventing the acetylcholinesterase from working - even though there is plenty of the stuff in the body. If that's true, then it wouldn't matter that fresh acetylcholinesterase is being produced. But as I said, this is only a guess. SteveBaker (talk) 00:43, 11 November 2013 (UTC)

The organophosphates inhibit acetylcholinesterase, which makes the signal from acetylcholine last longer. According to [5], these somehow lead to excitotoxicity, which leads to apoptosis. There is a lot left unclear in that "somehow", both in the paper and its sources I think; I haven't looked into it deeply but there may be some important biology undiscovered there. In principle though, we can see that more signalling can do that. The link I give even specifies some compounds that can interfere with the process. Wnt (talk) 02:40, 11 November 2013 (UTC)

Guessing is the problem here. [deleted suggested answer] This also sounds like a homework or test question. μηδείς (talk) 02:45, 11 November 2013 (UTC)

It might be, and then it might not be. I think we should give the OP the benefit of the doubt in this case. 24.23.196.85 (talk) 07:19, 11 November 2013 (UTC)

That's interesting it means that medicines to protect from damage due to strokes or epilepsy for instance might help as well as ones to block acetylcholine. I guess the ones looking at protecting from nerve gases have tried all sorts of things like that though. Dmcq (talk) 14:09, 11 November 2013 (UTC)

November 11

Plastic cracking due to rapid temperature change

Some plastics can be exposed to sudden changes in temperature (e.g. +21 to -190 C) without cracking while others can't. How can I predict this? Are certain plastics or plastic additives needed? Is thickness relevant? — Preceding unsigned comment added by 78.148.107.181 (talk) 13:49, 11 November 2013 (UTC)

This has to do with several factors, among the most important of which are the plastic's thermal conductivity, ductility and tensile strength: plastics with higher values for these parameters are less likely to crack due to temperature changes. Also, adding plasticizers reduces the likelihood of cracking, by increasing ductility. And yes, thickness is VERY relevant -- a thick piece is more likely to crack than a thin piece, due to thermal shock. 24.23.196.85 (talk) 00:31, 12 November 2013 (UTC)

Official Specs from Nissan (I don't have a Chilton book)

I'm trying to find specs for what Nissan says the thermostat opening temperature is supposed to be for a 2002 Sentra GXE. At Advance Auto's website, one with an opening temperature of 170 F says it's an exact match, but that's lower than specs I have seen from official sources for other engines and I'd like to see the temperature number Nissan itself says. I'm already getting the check engine light because my thermostat's stuck open and I'm running below optimal running temperature, and getting a themrostat that opens too soon will keep things that way. 20.137.2.50 (talk) 15:30, 11 November 2013 (UTC)

I don't have access to a reference to look up the specs right now, but you can probably get the answer with a call to a Nissan dealership's parts department. Katie R (talk) 17:49, 11 November 2013 (UTC)

Who's eating our high-energy neutrinos?

Does the failure of the IceCube Neutrino Observatory, as noted here http://www.wired.com/wiredscience/2013/11/future-physics-experiments/?cid=co14315194 indicate that something is sapping the punch of the Universe's high-energy neutrinos?

If so, could the culprit be dark matter? Hcobb (talk) 17:22, 11 November 2013 (UTC)

If Iron nuclei dominate the primary ultra high energy cosmic ray particles, then there isn't a problem. Count Iblis (talk) 18:43, 11 November 2013 (UTC)

Huh? What's the ref? Hcobb (talk) 19:19, 11 November 2013 (UTC)

I think it's disingenuous to say that the IceCube experiment "failed." It is an experimental apparatus, and the data that it has produced is still being interpreted. Two measurements were collected that imply extremely high energy neutrinos, but only with a low confidence (by the rigorous standards that are applied to particle physics experiments). I am not an expert in neutrino spectroscopy, but I think we should refrain from calling the experiment a "failure" just because a popular science writer glossed over the important details. The experiment has provided a lot more data than those two specific events. You can read an overview at IceCube Quick Facts; that webpage links to more technical publications, like this one that was published in PRL: First Observation of PeV-Energy Neutrinos with IceCube (2013). "These two events could be a first indication of an astrophysical neutrino flux; the moderate significance, however, does not permit a definitive conclusion at this time." That's the paper I'd be spending my time reading, if I were interested in answers - not a Wired.com article. Nimur (talk) 22:42, 11 November 2013 (UTC)

Storm surge timing

How long does it take for a storm surge, like the one that just destroyed Tacloban, to come ashore? In other words, how quickly does the water rise to its maximum level? I looked at storm surge but didn't see anything. --71.163.153.146 (talk) 18:53, 11 November 2013 (UTC)

Depends on how large the storm is and fast it is moving. Dragons flight (talk) 19:26, 11 November 2013 (UTC)

In the case of Haiyan, the tropical storm force winds extended about 300 km from the center, and the storm was moving 40 kph, so people would start experiencing a serious storm about 8 hours before the peak of the storm surge arrived. Dragons flight (talk) 19:43, 11 November 2013 (UTC)

• The surge from the storm moves at the same speed as the storm, but is affected by the tide and the shape of the land and any falling or rising of the storm's wind speed. In this case, if the storm was moving at 40kmph and the winds were not varying and the tide was not influential, and we ignore the shape of the coastline, the surge was moving at 40kmph. μηδείς (talk) 23:04, 11 November 2013 (UTC)

What's the reason for the large death toll? Is it because they were not adequately warned? Or were they warned but had no practical way to leave and seek higher ground? ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:30, 11 November 2013 (UTC)

• Storm surge is determined by a combination of air pressure, wind, and tide. The wind tends to give the strongest surge north of the eye, because it pushes water ahead of the storm, but in a complicated-shaped body of water such as the one that Haiyan passed through, the wind effects are difficult to work out. The main cause of fatalities is just that this was an incredibly strong storm. The only things the US has experienced that are comparable are the 1935 Labor Day hurricane and Hurricane Camille, but both of those made landfall in relatively uninhabited places, whereas Haiyan made landfall directly on a city of over 200,000 people. Looie496 (talk) 00:02, 12 November 2013 (UTC)

Have you forgotten Hurricane Katrina??? 24.23.196.85 (talk) 00:33, 12 November 2013 (UTC)