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August 2

protect US electrical grid

How important is it to protect the US electrical grid from electro-magnetic pulses and solar flares? There are people saying that it can be done for a few billion dollars and should be done. Bubba73 ^{You talkin' to me?} 01:15, 2 August 2013 (UTC)

See One Second After. I think chances are 50/50 this will get me, and higher I'll get a bureaucrat myself if it do. μηδείς (talk) 02:32, 2 August 2013 (UTC)

?? What dialect is your reply in, Medeis, and what does it mean? -- Jack of Oz ^{[pleasantries]} 03:55, 2 August 2013 (UTC)

How important to whom? Very important to the US, quite important in Europe, not at all important to certain other countries and regimes. See electromagnetic pulse and solar flare. The usual way to convince the taxpayers is to wait for something to go wrong, and then fix it.--Shantavira|^{feed me} 10:15, 2 August 2013 (UTC)

Important for the US, of course. A friend of mine saw someone on one of the CSPAN channels saying that we need to spend a few billion dollars to protect it. I don't know if he has legitimate concerns of wants to profit from it. Bubba73 ^{You talkin' to me?} 17:48, 2 August 2013 (UTC)

The dangers of coronal mass ejection and nuclear EMP and the damage they may cause to the grid infrastructure have been hyped by politicians, by the EMP commission (whose "experts" came from sectors like the missile defense industry, and recommended missile defense systems...) and by EMPact America. The writer of "One Second After" is a friend of Newt Gingrich (and co-author of some of his books), protection against an EMP attack by rogue states like Iran and N. Korea featured in Gingrich's campaign for the Republican nomination; it's the latest threat, after the WMDs of Sadam. The EMP commission has produced a number of reports with claims based on "classified evidence", there's speculation that this has more to do with the quality than the sensitivity of the material. One claim about Iran's secret plans turned out to come from an Iranian magazine that was in fact quoting a story from the NY Times or Washington Post. There's the claim of a Soviet super-EMP technique that was supposedly given to the Iranian and North Koreans (we've heard super-weapon claims before, like red mercury ).

The main points of those claimed dangers are:

• EMP would destroy all electronics that control the grid.
• Big transformers would be destroyed by EMP or by strong solar events, and replacing them will take years.
• Nuclear installations would go in meltdown because their controls aren't EMP-safe.
• without power, the US would fall back to the stone age and up to 90% of the population could die the first year.

In fact, safety of nuclear installations has been reviewed several times in the last decades, addressing those specific points. The grid is protected by circuit breakers and fuses: it will go down when such an event occurs, not because of damage, but because that's the only way to protect it, solar mass ejections and EMP can induce large currents in long conductors (not only electric cables but also in pipelines), cutting the circuit is the only option. There has been one documented case of a power station that burned down after a nuclear test, in the Soviet Union.

Claims that three nuclear bombs were enough to cover the whole country didn't take into account that the ionization of the outer atmosphere created by the first explosion would make it impossible to create a second EMP for days or weeks. For that reason a classic atom bomb is better than a hydrogen bomb, the tiny delay between the first and second stage is sufficient to prevent the second one having any effect.

There's a lot of nonsense being told, I've seen a video from a "prepper" (who supposedly prepare for such events) saying that without electricity there was no way to get at the gasoline from the tanks at gas stations; seems he doesn't know that during inspections these tanks are sampled with a beaker on a stick. Ssscienccce (talk) 13:01, 4 August 2013 (UTC)

Thank you, that was very informative. Bubba73 ^{You talkin' to me?} 16:41, 4 August 2013 (UTC)

Ssscienccce, what happens if the 3 bombs are detonated simultaneously? --220 of ^Borg 10:43, 7 August 2013 (UTC)

Resolved

As it wasn't mentioned here I'll just toss in that last years' (in the USA) Revolution (TV series) covers a related scenario, what happens if the electricity stops? Apparently the cause is not specified. (or is that where this query originates?) --220 of ^Borg 10:43, 7 August 2013 (UTC)

Things

Why so so many people online fight about whether Edison was cleverer / more significant than Tesla? 105.236.159.229 (talk) 11:49, 2 August 2013 (UTC)

People love to argue about all sorts of things - Android versus Apple, Mac versus PC, dogs versus cats, classic StarTrek versus STTNG (versus Voyager (versus Star Wars)), Ferrari versus Lamborgini...you name it and there is a vigorous online debate about it. Edison and Tesla were rivals during their lives - they both did a bunch of crazy stuff, so it's easy to take sides. Tesla is a particularly good topic to rant about because he claimed to have done so many amazing things. We're 100% sure he didn't actually do all of the things he claimed - and 100% sure that he did do some of them. So there are large grey areas in his achievements that are great fodder for online flame-wars. Edison is also a great target because he had a great propensity for taking things invented by his employees and claiming that he, personally, invented them...so again - he's a great target for debate. SteveBaker (talk) 14:29, 2 August 2013 (UTC)

Of course the Star Trek/Star Wars arguments are kind of silly, given that Babylon 5 is so much better than either one. --Trovatore (talk) 02:41, 3 August 2013 (UTC)

Did you see Pawn Stars last night? Edison and Tesla started the argument. Bubba73 ^{You talkin' to me?} 21:34, 2 August 2013 (UTC)

Tesla was more of a "pure" scientist, and wasn't all that good at public relations (it can't be a coincidence that the typical "mad scientist" kinda looked like Tesla). Edison was more of a "practical" scientist, and was much better at P.R. AC won out over DC, but we don't call the power company "Commonwealth Tesla". Tesla teamed with George Westinghouse to get into the practical side, but Westinghouse is the name we remember. Tesla sued Marconi over the invention of radio, and eventually won the suit, but we associated radio with Marconi nonetheless. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:57, 2 August 2013 (UTC)

They both did great things in their youth, and then made completely untrue claims in their old age. By picking and choosing which part of their life you look at, or how much of their claims you believe you can make it look like either was "Better".

On top of that "Invention" rarely happens like it does in the movies. People incrementally improve existing ideas. To say that any single thing was wholly invented by any single person is misleading. So that gives you the perfect "ammunition" to discredit inventors you don't like by pointing out the earlier work that they built upon. (While ignoring the fact that your favorite inventor did the same thing!)

However, I think a lot of the current drama over the two inventors can be traced back to this very misleading infographic/comic from The Oatmeal.

APL (talk) 02:38, 3 August 2013 (UTC)

Mick West who runs the site metabunk even thought it necessary to "debunk" Tesla's importance, as just another topic next to governement conspiracies like chemtrails, water fluoridation, killer vaccines and 9/11 inside job claims: http://metabunk.org/threads/tesla-overrated-debunked.894/. Ssscienccce (talk) 14:46, 3 August 2013 (UTC)

Loga

Why do dogs put their heads out the car window? 105.236.159.229 (talk) 11:58, 2 August 2013 (UTC)

I don't think we know for sure - but it's clear that the wind in their faces is enjoyable. I kinda suspect that they also like that smells are zipping past with incredible rapidity so they get the same experience of speed that humans get from looking out of the window. SteveBaker (talk) 14:22, 2 August 2013 (UTC)

This source corroborates Steve's version. It's not a scientific publication, but some kind of dog behaviorist. According to it, apparently, dogs do not enjoy being blown on the face, and it's even detrimental to them. But since their sense of smell is complex and advanced, they are exposed to a plethora of sensations. OsmanRF34 (talk) 22:29, 2 August 2013 (UTC)

Dogs definitely do not like wind in their face. When I have washed my dogs, I have dried them off with a hairdryer. It takes a few goes before they are not distressed by it, but after a while they clearly enjoy the sensation of warm air on their bodies, but never cold air and never on their faces, hot or cold. However, it is part of a dog's nature that they feel obligated to track the location of every living thing in the vicinity, and (depending on breed), bark at it at least once. That's what causes dogs to stick their heads out of car windows - so that their barks have a chance of being heard by all those things going past. Note that dogs determine whether or not something is alive is a simple rule: if it a) moves about in its entirety, and b) makes a noise, then it may be alive and needs to be barked at. Thus for a dog, a car going past may need to be barked at, even if no humans are clearly visible in it. Many owners of two dogs of the more intelligent breeds will have noticed that when both of them are in the car, only one puts his head out and barks - generally not the lead (alpha) dog. That's because with one dog doing the chores (barking at things and keeping track of them, the other dog can take a rest - delegation. 1.122.204.61 (talk) 13:08, 6 August 2013 (UTC)

Heat screen

Can you have a sort of heat cream that blocks heat in the same way that sun screen blocks UV? — Preceding unsigned comment added by 188.76.169.87 (talk) 12:16, 2 August 2013 (UTC)

Heat arrives by several mechanisms - conduction from the air in the environment and IR radiation from other hot objects (such as the sun) being the most obvious. You could perhaps design some kind of cream that reflects IR light away from you - but you'd still get hot from conduction from the atmosphere. You could certainly make something that evaporates like natural sweat to cool the body for a while - but it would dry out fairly quickly - so you'd need to re-apply it. In a sense, we already have this substance...just wipe your skin with a cloth soaked in plain old water - and you'll feel cooler...so obviously this is possible. SteveBaker (talk) 14:20, 2 August 2013 (UTC)

I remember seeing a stuntman that had invented a paste that you could put on your skin when doing fire stunts. He could set his hand on fire and let it burn for 30 seconds without feeling the heat. 217.158.236.14 (talk) 09:11, 5 August 2013 (UTC)

Could more co2 be good for the planet?

Without questioning global warming or that it's man-made, could we discuss whether it's a good thing? Who said that present or past levels of co2 are better than future higher levels? Who said that present or past temperature is better than a future higher level? — Preceding unsigned comment added by 188.76.169.87 (talk) 12:21, 2 August 2013 (UTC)

Well, it all depends on what you mean by "good" and "better". How do you measure "good" ? Good for who ? Our article on the economic impacts of climate change contains some possible answers. Broadly speaking, there is agreement that global warming will have economic costs, but there is disagreement over whether these costs could be catastrophic; whether they could be significant but manageable; or even whether they could be marginal compared to the long-term benefits of global industrialisation. Of course, if you are living on a small flat island a few metres above sea level, this debate must all seem very academic. Gandalf61 (talk) 12:49, 2 August 2013 (UTC)

Ok, good for nature, in the sense there's more of it. Or even agriculture, in the sense that we can produce more, maybe because there's more rain or a bigger area where we can plant. I suppose that many human communities will have to be re-located, which is not a big drama as such, since humans have always migrated. — Preceding unsigned comment added by 188.76.169.87 (talk) 12:54, 2 August 2013 (UTC)

There is lots of detail about agriculttural impacts in our artcile on climate change and agriculture. Headlines are a low to moderate degree of global warming is likely to increase food production in some parts of Asia and North America, but decrease it in the rest of the world. Gandalf61 (talk) 13:08, 2 August 2013 (UTC)

For more specific research, you may be interested in reading about SoyFACE [1]. Their research has identified many problems with growing crops in the midwest USA under higher CO_2 levels. One I found interesting: soy plants do grow a little faster, but their CN ratio also changes, and they end up getting more beetle damage. So the net result is still a negative impact on crop yields. SemanticMantis (talk) 13:10, 2 August 2013 (UTC)

Definitely NOT good for nature. Increased temperatures force plants and animals to migrate towards the poles - but the timescales of this change are too short for plants to spread very far - and much too fast for animals to evolve. I was listening to a report just a few days ago that trees that are normally resistant to forest fires in the south-western part of the USA are becoming less resistant because of climate change - and the overall increase in temperatures makes forest fires much more likely. The consequence of that will be the eradication of large forests in those regions. The trees don't have time to re-seed themselves further and further north because it takes 30 years to grow a tree - and each one can only travel a dozen feet from it's parent. At that rate of movement, these plants can't possibly outrun the effects of climate change - and face extinction.

This isn't good for humans either. If nature suffers - so will we. It's possible that human activity such as farming can move further away from the equator - but because our society has strict national boundaries - this will be disasterous for some countries and a win for others. The stresses that causes will result in international tensions - wars and other very bad things.

The idea that crops will do better because of increased CO2 levels is true for some species - but it's also true for some invasive species, native weeds and many diseases of plants - so it might be that our farmlands become overwhelmed by disease and non-productive species.

Truly, the result of this will be a massive loss of bio-diversity - and that cannot be good for mankind or "nature".

SteveBaker (talk) 14:14, 2 August 2013 (UTC)

In the long run the Earth can survive a lot, and what is "good" is quite mysterious. But in the short term any change is bad change. For example, if you lived on the Grand Banks 8000 years ago, the rising sea level would be a big problem. Return of the ice age would be a big problem. As in that example, sometimes there is actually no way for climate not to change (either sea level must rise or the ice age must return) but it still sucks! In our case though, we're shooting extra holes in the bottom of the boat. Wnt (talk) 14:57, 2 August 2013 (UTC)

It doesn't make sense to ask what's "good for" the earth. It only makes sense to ask what's "good" for us, or for some category of life. If the asteroid hadn't hit the earth, maybe the dinosaurs would have continued to flourish a lot longer, and would have eaten up all of our biological ancestors. So that event was bad for the dinosaurs, good for us, and neither good nor bad for the earth, as the earth is just an object. ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:26, 2 August 2013 (UTC)

Yes, if you do not count life forms as a part of the planet - that's true. Even life itself will probably continue flourish despite what mankind is doing here...but you might end up with oceans containing nothing but algae and jellyfish and land containing nothing but fire-ants and cacti. In time (just as after the other mass-extinction events) new species will evolve and the world will carry on - albeit in a different direction. Individual humans may not see a significant degradation in quality of life during their lifetimes - but each generation may have slightly harder lives than the previous. So any consideration of "better" and "worse" has to be made relative to what we, as humans and as a species, consider good and bad for the future survival of our genetic heritage. SteveBaker (talk) 17:27, 2 August 2013 (UTC)

In the very long term, isn't the occasional mass die-off a driving factor of evolution? With more complicated and "Advanced" species emerging after the die-off?

Not that I'd personally want to be one of the ones who die off, but if I were an immortal god, it might be interesting to roll the dice and see if something better than humanity crops up in the million years after an ecological disaster. APL (talk) 02:26, 3 August 2013 (UTC)

Evolution doesn't select traits that are "advanced" or "complicated", though. It's not a progression of "better" life forms so much as "life forms that survive/pass genes best in this environment". The other problem is that evolution doesn't plan: given two mutations: mutation A that makes the animal a little smarter and mutation B that makes it no smarter, but more agile. If A and B are mutually exclusive and B is better right now, B is going to win; even if a thousand years down the road, A would have been the better option.Phoenixia1177 (talk) 08:25, 3 August 2013 (UTC)

Whenever these discussions come up I'm reminded of this comic by Humon. (Note: much of the artists other work is NSFW.) It points at the difference between "good for the planet" and "good for us humans". Sjö (talk) 08:30, 3 August 2013 (UTC)

Phoenixia, I understand that, everyone knows that, but historically, haven't more complex (And therefore more "Advanced" so far as I'm concerned) life usually emerged from such global catastrophes?

(Specifically because, as in your example, after a mass die-off, there would be little competition for resources, so A and B are not immediately in direct competition, allowing a brief period of exaggerated biodiversity.)

I'm certain I've read that in a number of different sources, but I can't quite seem to find an article on WP that describes this idea, perhaps just because I don't know what it's called. APL (talk) 09:13, 3 August 2013 (UTC)

I don't think "everyone knows that", I think it get's pointed out a lot, and I think that's because it's a very common error that people make. You may not have meant that, but what you wrote can be read that way. As far as I've read, mass extinctions are important because, generally, what survives isn't strongly correlated with ability to survive prior to extinction event; so it hits across the spectrum of success. An effect of this is that with the dominant species removed, other species can diversify and, possibly, break current trends (not always the case). But I don't see any reason this would imply an increase in complexity/intelligence, just an increase in change as different groups take over dominant positions (and I'm not sure everyone even agrees that this is an extremely drastic effect.) Some things you may want to read: Extinction event under the evolution section, and [2], [3], [4], [5], [6], [7].Phoenixia1177 (talk) 10:03, 3 August 2013 (UTC)

• The climate change problem arises not so much because more CO2 would be bad per se, as because of the extremely rapid rate of change. Ecosystems in many places just can't adapt fast enough to keep up with the rate of warming. If we had been living in a world of 500 ppm CO2 for millions of years, our geographic distribution would be adapted to it, and we would not see it as a problem. Looie496 (talk) 17:32, 2 August 2013 (UTC)

The sheer number of humans on the planet is currently causing a major extinction event anyhow. Pumping huge amounts of carbon dioxide into the air and making life even more difficult for anything else is just one amongst loads of other things we're doing. We've parks to conserve some species we've taken a fancy to, they will die because they can't move. Dmcq (talk) 19:41, 2 August 2013 (UTC)

Hominids have been extinguishing species and altering the environment from the time they learned to hunt, build fires, grow crops, etc. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:54, 2 August 2013 (UTC)

It sounds to me like you don't see the difference between some people wearing a path across a field with their feet and tarmacing the whole field over and using it as a car park. Dmcq (talk) 08:09, 3 August 2013 (UTC)

Have you tried parking downtown? Sheesh! What's a few little bugs? Someguy1221 (talk) 08:31, 3 August 2013 (UTC)

I'll concede that we did, in fact, pave paradise to put up a parking lot. ←Baseball Bugs ^{What's up, Doc?} carrots→ 09:01, 3 August 2013 (UTC)

I'm looking forward to going to the tree museum though - and $1.50 for entry sounds pretty cheap. SteveBaker (talk) 14:26, 3 August 2013 (UTC)

I've just looked that up and seemingly it was referring to Foster Botanical Garden in Honalulu and the entrance fee is now $5, still good value. Dmcq (talk) 17:39, 3 August 2013 (UTC)

Klaatu is on his way to fix the problem. Count Iblis (talk) 16:09, 3 August 2013 (UTC)

Medicine package US and Europe

Why? In the US they seem to prefer a plastic jar, and in Europe they seem to prefer all pills packed individually. — Preceding unsigned comment added by 188.76.169.87 (talk) 13:11, 2 August 2013 (UTC)

Over here in the UK it seems to depend on the individual pharmacy. For example, I noticed at the old-fashioned chemist I went to last week the drugs were dispensed in a bottle, whereas when I go to Boots or a supermarket pharmacy I get the drugs in a blister pack. --TammyMoet (talk) 10:29, 3 August 2013 (UTC)

Our articles Packaging and labeling and Blister pack has some general information, and a little on packaging for pharmaceuticals, but nothing that explains the different preferences in the US and Europe. Sjö (talk) 20:39, 3 August 2013 (UTC)

There's a difference in how pharmacists work in the US and in Europe (chemists), which may play a role. In the US, they often open up bottles from the manufacturer and place them in new bottles, to change the quantity, label, etc. Blister packs don't lend themselves to this. In much of Europe this process is discouraged, since it introduces possibilities for errors, theft, adulteration, etc. So, blister packs work better there. StuRat (talk) 22:24, 3 August 2013 (UTC)

Pressurize

is it necessary to pressurize gas before burining.? give any referencve... — Preceding unsigned comment added by 175.101.60.14 (talk) 14:20, 2 August 2013 (UTC)

No, as pranksters with their acetoxy balloons can attest. But I wonder what the lowest possible pressure for a "rapid burning" reaction in a room temperature gas would be (I fear creativity about the definition of burning might obscure the answer) Wnt (talk) 14:53, 2 August 2013 (UTC)

No, but its way more effective to handle and transport that way. --Kharon (talk) 15:37, 2 August 2013 (UTC)

Not at all. The hydrogen pop test relies on the flammability of freshly prepared hydrogen gas at room temperature and pressure. Fuel-air explosives burn gases like ethylene oxide at atmospheric pressure with devestating effect. 202.155.85.18 (talk) 03:34, 3 August 2013 (UTC)

Combustible gas can also burn in a partial vacuum, so long as there is an oxidiser present, that being oxygen or not. Plasmic Physics (talk) 01:50, 5 August 2013 (UTC)

Vitamin overdose

Can you die from a vitamin overdose? How many multivitamins or vitamin E or vitamin b6 tablets would you need? Pubserv (talk) 18:07, 2 August 2013 (UTC)

Yes - see Hypervitaminosis A (and Vitamin poisoning, though that doesn't mention any fatalities). AndrewWTaylor (talk) 18:10, 2 August 2013 (UTC)

How many multivitamins or vitamin E or vitamin b6 tablets would you need? Pubserv (talk) 19:35, 2 August 2013 (UTC)

For vitamin A, Hypervitaminosis A#Pathophysiology says that 21,600 IU per day over an extended period can cause problems, while a portion of a polar bear liver can kill you in a single dose. Hypervitaminosis E gives a safe limit of 1500 IU per day. The B vitamins are water-soluble, so they don't build up over time the way the fat-soluble vitamins do; B vitamins gives an upper intake limit of 100mg of B6. --Carnildo (talk) 01:12, 3 August 2013 (UTC)

Xavier Mertz may have died of vitamin A poisoning - see the article on Douglas Mawson --TrogWoolley (talk) 18:18, 2 August 2013 (UTC)

Soluble medication pills.

When they dissolve in the mouth, do they begin to enter the body/bloodstream in the mouth, or does it happen afterwards/only in the stomach? Pubserv (talk) 19:32, 2 August 2013 (UTC)

This will vary with the type of medication. Some are absorbed quickly through the mouth (see Sublingual administration), whilst others are absorbed much more slowly through the stomach. Dbfirs 19:48, 2 August 2013 (UTC)

What if it's Zyprexa? Can general medicines (soluble medicines) be absorbed if it is ON the tongue? Pubserv (talk) 09:13, 3 August 2013 (UTC)

The active component of Zyprexa is almost insoluble in water. Maybe some people smash the pills and mix with water, but unless it was prescribed to be taken like that, no one should do. OsmanRF34 (talk) 22:37, 2 August 2013 (UTC)

Medicine without side effects.

Why can't we make medicine/drugs WITHOUT side effects? Pubserv (talk) 19:34, 2 August 2013 (UTC)

Because a side effect is just an effect we don't want, and we want our medication to be effective. If a medication doesn't have an effect, it's not a medication, it's inert. And if it has an effect (which it does by definition), there will be circumstances in which that effect is undesired, or a side effect. Most substances have multiple effects, of course, which, along with the problem of different substances affecting different people in different ways under different circumstances, provides a fuller answer to you question. - Nunh-huh 20:05, 2 August 2013 (UTC)

I find the legs on tables annoying. They get in the way. Why can't you design a table without any legs? Now there's a nice straightforward problem, it can't be anywhere near as hard as making drugs without side effects. Dmcq (talk) 20:14, 2 August 2013 (UTC)

"Medicines" without side effects already exist. Most homeopathic preparations fit that bill. Problem is they don't have any desirable effects, either. Dominus Vobisdu (talk) 20:21, 2 August 2013 (UTC)

They do have one effect: As a diuretic on your bank account. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:50, 2 August 2013 (UTC)

You can hang a table. Not sure if it technically stops being a "table", but you can still put chairs around it and eat. Might have to worry about your elbows banging chains instead of knees banging legs, but it solves the underlying problem. Drugs, yeah, much harder. No clue. InedibleHulk (talk) 06:18, 3 August 2013 (UTC)

Isn't that just like what happens with the medicines?, get off the ones that make you feel ill and you get ones that make you fat. Dmcq (talk) 08:19, 3 August 2013 (UTC)

Even oxygen has side-effect (that is, undesirable effects). It comes down to the fact that we are complex systems. But nature chose to re-use the same components in different body parts. You'll find the same protein, neurotransmitter, hormone in different parts, fulfilling a different function.

Aspirins, for example, prevents blood clots because they inhibit a certain group of enzymes in platelets. However, these same enzymes are also in the stomach lining and serve to protect it against acids. Aspirin cannot distinguish between them and so while it prevents clots, it also destructs the protection of the stomach lining leading to ulceration.

On a bright side, science strives to develop more target drugs.

For example II: histamine. It regulates sleep and wakefulness, but also your autoimmune system. An antihistamines would affect both processes, however, chemists were able to discover new antihistamines that bind to one specific histamine receptors, the one that regulate allergic responses. These antihistamines are present in allergy medicines that won't make you drowsy.OsmanRF34 (talk) 22:55, 2 August 2013 (UTC)

• This question was just asked, 10 days ago and the OP was answered at length. μηδείς (talk) 20:56, 3 August 2013 (UTC)

It was related but not the same. Pubserv (talk) 08:27, 4 August 2013 (UTC)

August 3

Crescent Moon illumination

I was just watching the crescent Moon (it's about an hour before sunrise here), and I noticed that, while I could see the sunlit crescent, I could easily see the dark part of the Moon as well. The thing is, the edge of the Moon on the dark, non-lit part seemed to be brighter than the center. Is it due to the Moon geography (lighter/darker parts), or due to some real effect? Thanks 208.80.154.136 (talk) 02:25, 3 August 2013 (UTC)

I think most likely what you are seeing is Mach bands (an optical effect). Looie496 (talk) 02:31, 3 August 2013 (UTC)

Yeah - I second that - it's a classic example of a mach band...essentially just an optical illusion. SteveBaker (talk) 05:34, 3 August 2013 (UTC)

Thanks, makes sense. 78.0.225.163 (talk) 20:51, 3 August 2013 (UTC)

Also note that the reason you can see the dark part at all is due to earthshine, that is, sunlight which reflects off the Earth to the dark side of the Moon, and then back to us (I can't help but think of the pinball opening credits at the start of 3rd Rock from the Sun). StuRat (talk) 22:16, 3 August 2013 (UTC)

Airliner emergency exits

Every commercial airliner I've ever been on had emergency exits of some type with clear instructions on how to open the door in case of a crash. Usually, if you're sitting in an exit row, the hostesses even come and instruct you on how to open it in case the pictographs aren't clear. Do these emergency exits only open if the plane is stopped on the ground? Could criminals/terrorists open the doors in flight for bailing out, or just for the chaos caused by loosing cabin pressure? 202.155.85.18 (talk) 03:25, 3 August 2013 (UTC)

According to this, you can't open them while the cabin is pressurized since they have to swing in. Dismas|^(talk) 03:31, 3 August 2013 (UTC)

Some of the ones I've seen don't swing at all. Pulling the lever actually detaches the door like a manhole cover, and then you throw it outside the aircraft, so I don't think pressure will hold those on. 202.155.85.18 (talk) 03:43, 3 August 2013 (UTC)

Do they go straight out or do you have to pull them in and then push them out lengthwise? Dismas|^(talk) 04:07, 3 August 2013 (UTC)

I think they just fall outside, but my hostess on that flight was from Thailand so she spoke a bit funny and maybe they do come in first. Googling around a bit I found that a new trend it apparently outward swinging doors that avoid having to pull the door inward against a throng of desperate passengers in fear for the lives. These are locked electronically in a fail-open arrangment. 202.155.85.18 (talk) 04:38, 3 August 2013 (UTC)

These say there is no possibility of opening them in flight.[8] [9] Apteva (talk) 04:49, 3 August 2013 (UTC)

Re. the overwing exits (which are the ones that "detach like manhole covers"), they DO have to be pulled INWARD to open -- so, in fact, cabin pressure WILL prevent them from opening. 24.23.196.85 (talk) 00:41, 4 August 2013 (UTC)

Supposedly most of them must come inwards slightly to unlatch then they pop outwards. This prevents them from opening at altitude.

I dunno if they also have other locking mechanisms that stops you from popping them open.

This wasn't always the case. Check out D._B._Cooper.

And also check out Door#Aircraft_doors, which lists four cases where the doors were opened during flight.

APL (talk) 07:23, 3 August 2013 (UTC)

All four of those doors were cargo doors, not passenger doors. Dan Cooper (D.B.) (not likely his real name) specifically chose that aircraft because it was the only type that you could parachute from, because it had a rear door. He asked the pilot to depressurize the plane so that the door would open. Whether he survived is unknown, but some of the money was recovered years later, on the beach. An unreferenced statement in our article says that instead, "The crew soon noticed a subjective change of air pressure" when the read door was opened. I will look for a reference to change that. Apteva (talk) 17:17, 4 August 2013 (UTC)

That line isn't surprising. I'll bet it's true. You can notice a change in air-pressure when you open a car window on the highway. (On some cars anyway. It has to do with air-flow around the car.) APL (talk) 00:30, 6 August 2013 (UTC)

Of course if the door opens outwards then the cabin pressure won't help. CambridgeBayWeather (talk) 07:27, 3 August 2013 (UTC)

Yes, a smaller aircraft is easier to open the door, but not easy. That one was not supposed to be possible to open. Apteva (talk) 17:17, 4 August 2013 (UTC)

A few weeks ago, I was up front in an Bonanza when my door popped open. (Our pilot was fidgeting with the door because he thought the seal was leaking, and "pop" it went). The cabin is unpressurized, and we were only starting our climbout, some 3500 or 4500 feet over the San Jose hills. But the airflow kind of wedged the door into a steady-state configuration, cracked at an exact angle so that air rushed into the cockpit and held the door fixed. Now, we were only going about a hundred fifty knots, but let me tell you: there was no amount or force that I could exert against the air pressure to move the door in either direction - not to open it any wider, nor to slam it shut. It was held exactly at the steady angle that the airflow dictated it should hang at. High-velocity air acting on a few square feet of door can easily generate hundreds of pounds of force.

The Bonanza's door swings outward, and is notorious for popping open in flight; the rushing air slamming my face was about the loudest air I've ever heard, and I was pretty glad I didn't have to land the aircraft. A few times, my Citabria's door has popped open, but I can usually slam it shut without effort, or slow to fifty miles per hour and slip it to get the door to close on its own; or my backseat passenger/co-pilot takes care of it for me. Because the Citabria flies so much slower, and the door hinge is a lot simpler, it has never been an issue to close in-flight. But we had to make the call to land the Bonanza with the door open (or continue on with the wind blasting me for another forty minutes or so). We landed at KLVK, and the tower didn't even acknowledge anything out-of-the-ordinary.

This is yet another good reason why pilots are legally required to keep their seatbelts fastened at all times; and shoulder harnesses must be fastened for takeoff and landing (FAR 91.107). Everyone thinks it's really stupid when the pilot falls out of an aircraft. Nimur (talk) 08:24, 3 August 2013 (UTC)

Slipping a plane at 50 knots? I hope this is at 1000 feet AGL or higher, and that you're current on spin recovery! 24.23.196.85 (talk) 00:44, 4 August 2013 (UTC)

Yessir, and compliant with 91.119 (minimum safe altitudes) and all other applicable regulations. As a pilot of a conventional gear, aerobatic aircraft - and one without flaps - we slip all the time - it's a normal operation as part of every crosswind landing, whereas a lot of Cessna pilots (and even my pal with the Bonanza) tend to treat the slip as an emergency-landing-procedure only, and crab it in every time. I have to know how to slip without stalling - it's a maneuver that gets checked as part of my tailwheel type rating (FAR 61.31(i)(1)(i)). But it'd be hard to spin even if I wanted: when I'm soloing, I'm way under maximum gross weight, well inside the aerobatic envelope, and the Citabria usually stalls (power off) at just about forty (40) miles per hour (mph, not knots, on our airspeed indicator). 50 mph with power gives me plenty of margin, especially because the buffeting onset of a stall is so obvious at those low speeds - everything starts rocking and rolling and the stick goes limp - long before the pitch-over, and long before I lose altitude. And remember - you cannot spin unless both wings are in a full stall. With engine power, it's sometimes not possible to pitch the Citabria to the stall (I just keep... pitching up and climbing. Fortunately, on the checkrides, there's always gonna be some extra dead weight in the back seat).

My door's popped open once in the pattern, in a climbing turn to crosswind at just about 400' absolute altitude, and on that instance my CFI in the backseat closed it for me. One other time I recall, the door popped open while I was by myself at around 3000 feet MSL somewhere over the foothills near Skyline Boulevard. If you read the Airmen Practical Test Standards, we're supposed to be able to handle these sorts of "reasonable distractions" without panic or loss of control of the aircraft. It's probable that my CFI opened our door on purpose, on at least one occasion, just to check if I could handle a "realistic" distraction and maintain safe flight. He's definitely created more serious distractions: most memorably, he tried to take my eyes off the runway at short final by tapping me on the shoulder to point out a P-51 downwind in the pattern on the other runway. He later told me it really was a real P-51 and that I missed a pretty rare sight. I was unable to ever verify independently.

The point of all this side-story, as pertains to the original question: a door opening in flight does not need to be an emergency. In fact, a door falling off in flight is not even an "emergency" or an "incident" according to the legal definitions of those terms, as specified in the FARs or the NTSB safety regulations. Now, an airliner at 30,000 feet with a pressurized cabin is not equivalent, obviously, to a small general aviation aircraft. For one thing, passengers require supplemental oxygen if the door opens and the cabin depressurizes. Even still, that scenario is neither an emergency nor an incident, unless the pilot in command believes the open door jeopardizes the safe outcome of the flight. Nimur (talk) 02:36, 4 August 2013 (UTC)

Thanks for the clarification. For my part, all of my flight training was in the faster and heavier Cessna 172, which starts to mush at 55 knots with flaps up (although it can fly as slow as 40 with them down) and has a safe landing speed of 65 knots -- which is why I thought 50 would also be close to a stall in your case. 24.23.196.85 (talk) 01:04, 6 August 2013 (UTC)

The small emergency exits operated by passengers are plug doors so they cannot be opened by a human being when the cabin is pressurized. To be opened on the ground, the passenger must open the door inwards and then dispose of it. This is best done by moving the door to a horizontal position, rotating it through 90 degrees so it will pass easily through the exit, and then throwing it out onto the wing or onto the ground. (In some genuine emergencies, conscientious passengers have passed the door back to other passengers in the cabin, out of concern that throwing the door outside onto the ground will damage it. However, this is misguided because in an emergency when the cabin is to be evacuated the value of this small door is insignificant.)

In an unpressurized aircraft, it would be possible to open the small emergency exit in flight. Dolphin (t) 05:25, 4 August 2013 (UTC)

Where do kangaroos come from and what are they made of?

I don't mean Australia and meat, but in an evolution sense. Do we know what common grandparents they share with each of the mammals they sort of look like (goat, possum, human, rabbit, etc.)?

I've tried Googling, but only find archaeological and zoological stuff (I don't really trust those guys). I don't understand genetic terms enough to Google efficiently, but I can mostly understand them in context once I have them (same with French). A push in the right direction would be nice, if nobody has a definitive answer. InedibleHulk (talk) 06:12, 3 August 2013 (UTC)

Does Marsupial#Evolution help? Ghmyrtle (talk) 06:54, 3 August 2013 (UTC)

Macropodidae, the taxonomic Family (biology) of kangaroos may also be of interest. Try also "zoological stuff" at "Macropodidae (kangaroo)". The Paleobiology Database. Australian Research Council. 2011. The evolutionary split between mammalsplacentals(us) and marsupials (kangaroos) was apparently 160 million years ago, as near as we can tell so far. See New York Times, August 24, 2011 "A Small Mammal Fossil Tells a Jurassic Tale", and Daily Mail (UK), 19 November 2008 "Kangaroos 'are closely related to humans', scientists claim". "Kangaroos: Biology of the Largest Marsupials" page 6, dated 1995 so out of date now. --220 of ^Borg 14:45, 3 August 2013 (UTC) Corrected! --220 of ^Borg 06:29, 4 August 2013 (UTC)

Quick clarification/correction. Marsupials *are* mammals. Certified, paid-in-full, card-carrying mammals. The distinction you wish to draw between marsupials like kangaroos and possums and other mammals like humans, goats, rabbits, dogs and elephants is the difference between marsupials and placentals. (Here we should also mention monotremes, which are also true mammals, but are considered neither marsupials nor placentals.) - I agree, though, that looking at (modern) taxonomy, as refelected in the trees given in most taxonomic articles, is probably the best way to get a sense of how closely related things are, and what sort of diversity you get from the common anscestor. -- 71.35.121.78 (talk) 17:42, 3 August 2013 (UTC)

Whoops, IANAZOS! (I Am Not A Zoologist Or Similar!) Corrected! Thank you 'IP 71.' --220 of ^Borg 06:08, 4 August 2013 (UTC)

Another correction: Our common grandfather with kangaroos is apparently 150 million years old, not 160. Not sure if that was a typo, or if there was something in that Google book I didn't see (says I reached my viewing limit, which is apparently zero). Strange to hear it was about 80 million years before we split from mice. Can't judge a book by its cover, I guess. InedibleHulk (talk) 05:53, 4 August 2013 (UTC)

Actually, I suppose either could be considered a good enough guess. I see the first link went with 160. Ten million years seems like a long time, but it's small, percentage-wise. I'm sure the exact answer doesn't end in round zeroes, whatever it is, but we'll never know the exact one. InedibleHulk (talk) 06:05, 4 August 2013 (UTC)

Do marsupials carry their cards in their pouches ? :-) StuRat (talk) 22:13, 3 August 2013 (UTC)

The kangaroos native to the Greater Nottingham area of the UK (!) apparently do. -- Jack of Oz ^{[pleasantries]} 22:34, 3 August 2013 (UTC)

Naturally, they don't have wallets, though they can be made into wallets. (and coin purses) --220 of ^Borg 06:08, 4 August 2013 (UTC)

Yes, I recall Craig Ferguson using a kangaroo's "coin purse" as a prop on his show. :-) StuRat (talk) 22:03, 5 August 2013 (UTC)

Thanks, people. It all helps. These creatures have baffled me for long enough! InedibleHulk (talk) 05:45, 4 August 2013 (UTC)

What part of your brain is "You"?

Is there a section of your brain that contains nothing but your knowledge that you are you? — Preceding unsigned comment added by 174.65.3.227 (talk) 06:50, 3 August 2013 (UTC)

There doesn't seem to be any one part of the brain responsible for the sense of self (despite what popular science books often tell you, for most tasks, activity is spread to some extent in pockets across the brain, and the precise pattern can vary from person to person and even thought to thought). Nevertheless, neural basis of self has a lot of information you'll probably find interesting. Smurrayinchester 06:58, 3 August 2013 (UTC)

You may also be interested in the philosophical mind-body problem. SemanticMantis (talk) 13:59, 3 August 2013 (UTC)

I recommend Consciousness#Neural_correlates which covers this exact issue. SteveBaker (talk) 14:17, 3 August 2013 (UTC)

Maybe interesting in this context: persons with split-brain . In some situations two identities seem present, for example one half slapping the other half's hand when it interferes during a test. http://www.legiontheory.com/split-brain.html Ssscienccce (talk) 15:39, 3 August 2013 (UTC)

• Your question is a category mistake. Most people equate themselves with their consciousnesses (potential and active) which is not a physical part of your brain like a neuron, but a relationship between your body and the world. This is in a similar way metaphysically that your bank account balance is not a drawer, but a relationship between you and your bank. "You" are an emergent phenomenon of your body. μηδείς (talk) 20:52, 3 August 2013 (UTC)

As I read it, the question is asking whether there is a part of the brain responsible for the sense of personal identity. It's a difficult question, partly because we have no real understanding of the way our brains assign identity to parts of the world in any respect. Looie496 (talk) 21:11, 3 August 2013 (UTC)

There are parts of your brain, which, if destroyed, will cause you to lose your selfhood in some sense, such as the ability to make command decisions with your frontal lobe, or your ability to make new memories or recall old ones. But these are all parts or faculties of your self. Even Terri Schiavo still has a certain self after the trauma she suffered. μηδείς (talk) 21:22, 3 August 2013 (UTC)

I've pondered this for years, mostly in the form of worrying whether this part, if it exists, will be absorbed by a tree's roots after I die. I don't ever want to even be vaguely aware that I'm wood for the foreseeable future. That's still all I know for sure. InedibleHulk (talk) 06:12, 4 August 2013 (UTC)

There isn't a shred of scientific evidence that would support your concern; i.e. once you have decomposed, there is no scientific evidence that your consciousness persists. The rest is religion and superstition, not science. -- Scray (talk) 13:26, 4 August 2013 (UTC)

Before even that. Electrical signals through the brain are what makes thought possible. The definition of death in most parts of the world is "brain death" - defined as the time when no electrical activity is detected in the brain. At that point, there can be no more consciousness. So you'll certainly be unaware of anything beyond that point. Think of it like a computer (which is what your brain mostly is) - when you turn off the power, all of the programs stop running. Even though the computer is still fully functional - without power, it can do no work. Same deal with the brain. SteveBaker (talk) 14:07, 4 August 2013 (UTC)

Thanks for the assurance, but maybe I should have been clearer. I'm not talking about my "self" as my thoughts, memories and self-image. I'm fairly certain that's erased. But there's some reason "I" am locked to this particular body rather than you or the next guy (or your's or the next guy's). Maybe associating with just one brain is an automatic consequence of having/being that complete brain. But maybe the awareness is only the piece the consciousness (or whatever mysterious senses trees have, if any) is built around (like a computer's non-volatile memory), as essential and recycled as the pieces that give physical form to new life. The lack of evidence for this is somewhat comforting, but the lack of proof against it leaves me wondering. No big deal, I guess. I won't remember worrying about it, anyway. InedibleHulk (talk) 08:48, 6 August 2013 (UTC)

Yes, but from the computationalist point of view, you could still argue that you will always find yourself subjectively alive in the World as it existed before you died. If what we are is the program that the brain is running and if the hardware doesn't matter, then you can look at the World as it exists now and say that some machine is executing some particular program, but you can also apply the time evolution operator to the entire World and argue that the World as it is exists now is a scrambled version of the World that existed yesterday, so there are then machines that execute different programs which are experiencing yesterday's World. Count Iblis (talk) 15:41, 4 August 2013 (UTC)

Or just "No". SteveBaker (talk) 21:46, 4 August 2013 (UTC)

What is "your knowledge that you are you"? If you mean the learning of a name, perhaps you can rummage about in the hippocampus for it. The argument can certainly be made that you aren't you from a different time in your life, either physically or mentally, and that you merely have access to some memory of your former selves. In the opposite direction, all people may be instances of the same algorithm, manifestations of a common atman. In addition to these things I entertain a fringe theory of the soul as related to a progression of parallel universes; but parallel universes are not subject to scientific investigation. Wnt (talk) 20:40, 5 August 2013 (UTC)

You have two insulae, one on either side of the brain. Each is buried at the bottom of a deep, almost horizontal fissure that separates the temporal lobe (the large region above your ears) from the rest of the brain. Most of the brain's cortex {the wrinkled gray matter containing the nerve cell bodies) lies on the surface of the brain hemispheres, but the insulae are "islands" of cortex, buried deep within each hemisphere. "Insula" is Latin for "island".

This "insular" cortex seems to be involved in awareness/consciousness. Five or six years ago I noticed a report of some brain-scans, where the researchers inflicted mild pain on the subjects, which, as usual, activated the anterior (front) and middle portion of each insula and the other parts of the pain network - the pattern of brain regions that is activated by pain. Then the researchers presented something so interesting to the subjects that they were temporarily distracted from the pain. As the subjects lost consciousness of the pain, the anterior insula activity returned to the default level.

AD (Bud) Craig proposes that this area is the key to consciousness, and so self-consciousness. In this 2011 interview he discusses his theory, as explained in his (very difficult) much-cited 2009 paper. --Anthonyhcole (talk · contribs · email) 21:37, 5 August 2013 (UTC)

One article of interest might be Philosophical zombie (that's what a fully functioning "human" without consciousness would be called). You might also wish to read some blog posts (many linked from [10]) by Edward Feser (red link - I wonder if he would be notable in sense of Wikipedia:Notability..?), where, in effect, he explains why your question makes no sense. At least from perspective of Aristotle and St. Thomas Aquinas. --Martynas Patasius (talk) 22:11, 5 August 2013 (UTC)

R/C control of a 12v drive motor

I am working on a cart that I would like to operate by R/C. It would drive ,reverse and steer hopfully using hobby R/C transmitter and reciever. The current draw for the driver motor is 11 amps. This is to much current for the receiver contacts. So, I need a way to vary the drive motor speed, reverse this motor as well as control the motor that would handle the steering. If this is feasible, I would like to know the following:

1. What type of relays (drive & steering) are needed?
2. Should the relays be of a latching type?
3. can you reccomend relay part numbers that might be used? — Preceding unsigned comment added by Campy2 (talk • contribs) 13:24, 3 August 2013 (UTC)

I wouldn't use relays...those are ON/OFF devices and to drive this thing in a reasonable fashion, you'll need analog controls.

The simplest "do it yourself" way to do this if you are clueless about electronics is to rig up a rotary potentiometer to control speed and to use an R/C servomotor to turn the knob...that avoids any complicated electronics and reduces the problem to a mechanical matter.

It's hard to comment on steering without knowing how this machine steers - are you doing skid-steering (by having one motor for the wheels on one side of the cart and a separate motor for the wheels on the other side) or are you turning the wheels as you would on a car? The former is fairly easy because you just need two speed controllers and you don't have complicated linkages to rig up.

This gizmo (for example) provides two 20Amp motor drives at anywhere from 7v up to 30v and can be controlled from an R/C receiver. At $175, it's not cheap...but it's a one-stop solution that solves all of your problems in one go. That's just the first one that Google turned up - I'm sure there are many robotics parts vendors making and selling such things - so you should probably shop around for a cheaper one.

SteveBaker (talk) 14:14, 3 August 2013 (UTC)

Chinese shops are cheap, which may also reflect the quality, but still.. http://www.hobbyking.com is one, there's also a search engine for such sites: http://chinaprices.us/ give in "speed controller 20A" and you get a listing of sites with the component , price and conditions. Starts at $8.13, shipping included. Obviously not so versatile as the one Steve mentions; only one motor, max 16v and 20A continuous or 25A peak and needs an R/C receiver.. Ssscienccce (talk) 15:59, 3 August 2013 (UTC)

Usefulness and accuracy of racialist website

http://www.geocities.ws/racial_reality/race.html This site, is it's racialist view true to current science? I'll quote part of the above page below:

"Anti-racist PC agendas and the American Anthropological Association's recent confirmation of the unity of the human species have led to the belief that race is a socio-political invention that promotes racism. An ironic accusation since the denial of the science behind race is what's politically motivated."

The above site is also claiming that there is aside from genetic a morphological basis for race and that race has a taxonomic significance, it also holds that the works of Carleton S. Coon are very relevant to the understanding to race. — Preceding unsigned comment added by 76.68.41.170 (talk) 13:42, 3 August 2013 (UTC)

See our articles Scientific racism and Race and genetics. AndyTheGrump (talk) 13:49, 3 August 2013 (UTC)

Will do, but any comments on just the above site? — Preceding unsigned comment added by 76.68.41.170 (talk) 13:53, 3 August 2013 (UTC)

Wikipedia would not consider a geocities site a reliable source. SemanticMantis (talk) 14:01, 3 August 2013 (UTC)

Is the information on said site good though? — Preceding unsigned comment added by 76.68.41.170 (talk) 14:03, 3 August 2013 (UTC)

The website does not present a balanced view of the current perspective on the issue. AndyTheGrump (talk) 14:08, 3 August 2013 (UTC)

Would you say that the site uses good sources? — Preceding unsigned comment added by 76.68.41.170 (talk • contribs) 14:15, 3 August 2013‎

Cherry-picking sources to supposedly prove a point is never good. AndyTheGrump (talk) 14:18, 3 August 2013 (UTC)

There's also one question I have about the above site's claims, are Mongoloid, Caucasoid, Negroid, Australoid and Capoid actual viable taxa? — Preceding unsigned comment added by 76.68.41.170 (talk) 14:29, 3 August 2013 (UTC)

They are not recognised as such. AndyTheGrump (talk) 14:30, 3 August 2013 (UTC)

Does race have a taxonomic basis then? — Preceding unsigned comment added by 76.68.41.170 (talk) 14:47, 3 August 2013 (UTC)

No. AndyTheGrump (talk) 14:50, 3 August 2013 (UTC)

• It's an oversimplification to deny the validity of anything that has to do with race. A look at Y-DNA haplogroups and Mt-DNA haplogroups show that humans do separate roughly into African and extra-African populations. Of the extra-African populations, some retain early traits (Negritos, Australians, New Guineans). Earlier old-adapted groups exist in Siberian and the Americas. In the Eurasian west blond hair and blue eyes arose, probably due to sexual selection, while in the east the epicanthic fold perhaps arose for the same reason. Continental and subcontinental populations will have distinctive blood types and markers [11] and resistance for various diseases such as tuberculosis and malaria. None of this is false, although little of it is very important, and its implications are only statistical, with a huge amount of variation and exception. The problem academically is the overreaction on the left to prior invalid political arguments made on the right. Luigi Luca Cavalli-Sforza's work on the correspondences between genetics and language is impeccable, Carleton Coon's work is rigorous, if merely descriptive and speculative. He's certainly a must read if this sort of topic interests you. And it does interest a lot of people, in the same way people collect rocks or figurines; people are fascinated by variation and classification. μηδείς (talk) 17:22, 3 August 2013 (UTC)

• Does the site claim that any particular race is superior to the others? If so, then it's automatically bogus. The pre-emptive quote "Anti-racist PC agendas..." is particularly telling. ←Baseball Bugs ^{What's up, Doc?} carrots→ 19:50, 3 August 2013 (UTC)
  • Our taxonomy article says, "Taxonomy is the academic discipline of defining groups of biological organisms on the basis of shared characteristics and giving names to those groups." The name of our own group is the species Homo sapiens. Anyone in the species with functional reproductive systems can mate with an opposite-sex member of that group likewise having a functional reproductive system, and that mating will produce another member of Homo sapiens. ←Baseball Bugs ^{What's up, Doc?} carrots→ 19:56, 3 August 2013 (UTC)

Taxonomies don't really work well at a below-species level, since branching implies genetic isolation, and true isolation is speciation, while our models have multiple migrations with at least three into the Americas, various ones back into Africa by pastoralists (all the Way down to the Zulu of the Cape by way of the Nile, across the Sahel, and down the slave coast. Europe was invaded by the PIE peoples from the Eurasian Steppe followed by the Huns/Bolgars/Turks/Mongols out of Central Asia. The latter groups also invaded China Korea and Japan in various waves. So strict taxonomies are very much vague approximations. μηδείς (talk) 20:37, 3 August 2013 (UTC)

• I'm not sure if you want the site reviewed or just that page. That page is about results from [12] (online at the author's site) and obviously you'll get more respect quoting Science than quoting "Racial Reality website". But skimming the website's page I didn't notice them saying anything too outrageous - we know that you can tell what race someone is by looking at them, and the same is going to be true if you do AMOVA on their genes. It crushes what is almost a strawman - the claim that race is purely a fiction. This isn't really something that is actually believed; it is more the result of some well-meaning people saying factual things to dismiss the role of race without clarifying the things that give it some meaning, and other well-meaning people summarizing that down without realizing what was being left unsaid. To be clear, you can tell what race some people are by looking at the shape of their skull ... which would seem to imply different brains ... the problem is, phrenology never worked. It's by no means obvious why it never worked - given how easy it is for a small injury to cause major disability, you'd think that any variation in the brain is super important. Yet in practice there are huge internal variations including having large portions outright missing that can have no obvious effect on the person's intelligence or behavior. When brains are consistently smaller (women) the function is no different even on average. The uniformity of human general intelligence is one of the great mysteries of science. Wnt (talk) 05:00, 4 August 2013 (UTC)

Is it true that Carleton Coon's work is still useful in the study for race? Also, isn't Peter Frost's hypothesis is not more popular than others (IIRC)? And if there is an answer to this, how many races are there based only on biology, and how they are delineated, and can looking at DNA tell one their race. Also, since race does exist, can it mean different traits in different races, such as intelligence or capability? Most of these questions are related to things asserted on the site. — Preceding unsigned comment added by 76.68.41.170 (talk) 16:44, 4 August 2013 (UTC)

Coon's work predates the genetic study of human populations. For that reason it is of interest now historically, in the same was as the work of Georges Cuvier or John James Audubon. His data may still be of some interest. His theories were never tested or refined against the genetic data started to become available the decade he died. He shouldn't be quoted now as a theoretical authority. μηδείς (talk) 17:37, 4 August 2013 (UTC)

So does craniofacial studies of Coon hold any water in current scientific field? — Preceding unsigned comment added by 76.68.41.170 (talk) 18:30, 4 August 2013 (UTC)

See Carleton S. Coon. Personally, I don't have the patience to figure out his implications and their role in political development; my feeling is that if Mawr had a good word for it, it wasn't bad science, but of course, having genome sequence from many individuals really matters. Wnt (talk) 19:32, 4 August 2013 (UTC)

You mean Mayr. You don't get better than a recommendation from him. μηδείς (talk) 19:46, 4 August 2013 (UTC)

Cranio-facial studies provide data. One can then say certain features are typical of and make a certain population distinct. To abstract from such studies and posit a theory of the origins of the white race is just that, theorizing. Some current data agree with Coon in various aspects--whites apparently do have Neanderthal admixture (but so do all extra-Africans). Mediterraneans do form a coherent wave out of the Middle-East according to Cavalli-Sforza. But reams of other new data have no place in his theories--for example, the PIE peoples are a late introduction into europe, and if one identifies them with the true whites one use modern data to say Mediterraneans invaded their land. It is not really helpful to keep asking if he is authoritative. Topics like this require years of broad study--neither acceptance of an authority figure nor ideological dismissal. Ignore the man and look at the data. μηδείς (talk) 19:46, 4 August 2013 (UTC)

What ideological dismissal? I asked the question on a scientific basis, would you say that his data would be good proof for the existence of race? And if his racial theories are actually proven in some fashion. — Preceding unsigned comment added by 76.68.41.170 (talk) 22:09, 4 August 2013 (UTC)

I did not accuse you of dismissing things based on ideology, I suggested one not do it. Race is a concept whose usefulness depends on how you define it and in what context. If the coroner tells you the body was that of a black female between 18 and 30 you don't ask him to prove races exist; neither do you actually expect proof of the existence of races if someone tells you black people bear the Mark of Cain. μηδείς (talk) 17:18, 5 August 2013 (UTC)

But then what are the objective scientifically determined races? — Preceding unsigned comment added by 76.68.41.170 (talk) 21:05, 5 August 2013 (UTC)

Zyprexa interacting with vitamins.

Can Zyprexa interact with vitamins? Pubserv (talk) 18:32, 3 August 2013 (UTC)

It is a very simple matter to google that question; we are not medical experts, and if you have Zyprexa you have a doctor who prescribed it and a pharmacist who filled it, both of whom will answer your question. μηδείς (talk) 20:44, 3 August 2013 (UTC)

I don't have access to Google on my computer. Pubserv (talk) 08:26, 4 August 2013 (UTC)

Are you Cuban? What kind of people has access to Wikipedia but not Google? OsmanRF34 (talk) 12:04, 4 August 2013 (UTC)

No. Those people that have restricted access to websites. I hope I'm not the only one. Have, not has. Pubserv (talk) 19:11, 4 August 2013 (UTC)

No. It's has not have. This kind (of people) has access to something. OsmanRF34 (talk) 01:52, 5 August 2013 (UTC)

• I have encountered other WP editors with the same restrictions, e.g. access only at work, which allows WP but not Google. -- Scray (talk) 19:30, 4 August 2013 (UTC)

How does that work??? - is WP on a whitelist, or is Google on a blacklist? Is Ixquick allowed to them? How are they supposed to use the web at all without a search engine? Wnt (talk) 01:55, 5 August 2013 (UTC)

How? Do you need a search engine when you only have access to 4 sites/themes, like me? Pubserv (talk) 18:11, 7 August 2013 (UTC)

How much vitamin B6 for akathisia?

How many tablets are needed to relieve akathisia? Or how much? Pubserv (talk) 19:08, 3 August 2013 (UTC)

I"m sorry, we're not allowed to offer medical advice. SteveBaker (talk) 19:17, 3 August 2013 (UTC)

You need to see a doctor about that. Whatever he deems the right treatment to be, your doctor would recommend a dosage based on appropriate factors. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:01, 4 August 2013 (UTC)

I can't see a doctor. Pubserv (talk) 08:25, 4 August 2013 (UTC)

Then ask your pharmacist, they can also provide qualified advise, and they are free. OsmanRF34 (talk) 12:02, 4 August 2013 (UTC)

I can only see a psychologist, that's not a pharmacist, right? Pubserv (talk) 19:14, 4 August 2013 (UTC)

What kind of people has no access to a pharmacist? OsmanRF34 (talk) 01:54, 5 August 2013 (UTC)

They might at least have a clue, and could have a direct conversation with you about it. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:59, 4 August 2013 (UTC)

See here. Count Iblis (talk) 19:36, 4 August 2013 (UTC)

I would advice you against trying this out yourself unless a qualified doctor prescribes it. I would not go to a farmacist unless you live in a country where they can be trusted to give qualified advice (in most of the Third World countries farmacies cannot be trusted, they are just interested in selling as much as they can). The potential problems that a doctor will have to look into are the following. The dose you need to take is of the same order as the dose where toxicity symptoms can start to manifest itself if you were to use this long term. Also, for long term use, even if you take large but not extremely large near toxicity level dosages, you should normally not do that for any specific B-vitamin (with the exception of B12) and instead use a vitamin B-complex. The different B-vitamins have a similar structure and if you take a large dose of one, your body will increase the excretion of not just that one but also of other B-vitamins, causing you to be come deficient in these other B vitamins, even if you get normal dosages of these other B vitamins via your food.

These are just some potential problems that a doctor will have to verify are not going to be relevant in your case during the course of some specific treatment. Count Iblis (talk) 13:18, 5 August 2013 (UTC)

What's a "farmacist" -- a farmer who grows medical herbs? 24.23.196.85 (talk) 04:46, 6 August 2013 (UTC)

• Our article has a section Vitamin_B6#Toxicity - I would say this and especially the sources it cites are advisable to read if you're contemplating any B6 treatment, with or without a doctor's help. (The sourcing is still weak in places...) Wnt (talk) 20:26, 5 August 2013 (UTC)

August 4

# of days Medicare pays in rehab

My friend was told Medicare would pay only up to 20 days in rehab. Is this new? It used to be 30 days.```` — Preceding unsigned comment added by 71.232.189.242 (talk) 01:14, 4 August 2013 (UTC)

I believe that is true, and then it pays 80% out to 100 days. But I may be wrong. Bubba73 ^{You talkin' to me?} 01:43, 4 August 2013 (UTC)

It's probably worth pointing out that there is more than one country in the world with a health scheme called Medicare. And, not surprisingly, they're not all the same. HiLo48 (talk) 02:27, 4 August 2013 (UTC)

Yes, but it is unlikely that someone from Massachusetts would be interested in any program from outside the U.S. --Jayron32 03:08, 4 August 2013 (UTC)

North America (USA & Canada) plus Australia, at least use 'Medicare'. (National Health Service(NHS) in England) --220 of ^Borg 06:52, 4 August 2013 (UTC)

Missed Medicare Resources in Hong Kong. --220 of ^Borg 07:23, 4 August 2013 (UTC)

In Canada it is only called medicare in New Brunswick. TFD (talk) 07:31, 4 August 2013 (UTC)

Bee-eater pic

In this picture of a European bee-eater, what's that butterfly it's holding in its beak? 24.23.196.85 (talk) 05:55, 4 August 2013 (UTC)

Looks like Vanessa cardui. What you see are mostly the undersides of the left fore- and hind-wing. --Dr Dima (talk) 01:49, 5 August 2013 (UTC)

Thanks! I prob'ly should've known this -- it's one of the most common lepidopterians in the world (better known as the Painted Lady). BTW, does anyone know whether it's toxic like the Monarch? I've checked the article, and it says nothing about that. (It does say in the Bee-eater article that the bird avoids certain toxic insects, but doesn't say which ones -- only that it (obviously) doesn't avoid bees, which are also quite toxic.) 24.23.196.85 (talk) 05:31, 5 August 2013 (UTC)

No definitive reference found either way, but in 45 years of active interest in lepidoptery, I've never seen it suggested that this or related species in Great Britain are significantly poisonous to birds. {The poster formerly known as 87.81.230.195} 212.95.237.92 (talk) 14:10, 5 August 2013 (UTC)

...and the mere existence of that photo strongly suggests that these birds don't avoid them! SteveBaker (talk) 15:28, 5 August 2013 (UTC)

Presuming, of course, this bird isn't suicidal, stupid or visually impaired. From the frequency other species crash into my clearly dirty windows, I'd say "seems to suggest". InedibleHulk (talk) 09:36, August 6, 2013 (UTC)

Father

Is it possibe to make a dead man father children through Testicular sperm extraction? Pass a Method talk 12:34, 4 August 2013 (UTC)

That process requires live sperm, so it will be progressively less successful as the sperm die following the death of the man. The time from death until there are no viable sperm will depend on many conditions, including the condition of the testicles at the time of death. This search for direct answers was unrevealing. -- Scray (talk) 13:22, 4 August 2013 (UTC)

Was the sperm extracted before or after death? A dead man can have previously donated sperm the normal way, and had it properly frozen. The thawed sperm can then be used to posthumously conceive a child. --Jayron32 01:54, 5 August 2013 (UTC)

Would a man who froze to death and stayed that way be a candidate? InedibleHulk (talk) 09:38, August 6, 2013 (UTC)

Is it possible to study human language development

Is it possible to study human language development by filming a human from birth to death and recording down all visual and audio signal that a human has come across in their lifetime. This capability must surely be possible with the budget of a large country like USA. The source of data will be useful for scientists for hundreds of years to come to analyse the psychological development of a human. So why was this not initiated? Surely the scientist around the world can easily obtain funding to perform the experiment. It cannot be because of privacy because the data(film) will never be released to the general public. 220.239.51.150 (talk) 15:38, 4 August 2013 (UTC)

Sure it's possible, it just isn't very practical (not to mention that it raises a plethora of ethical questions). Anyway, the ref desk really isn't the place to speculate on such things... 70.112.97.77 (talk) 16:18, 4 August 2013 (UTC)

Bear in mind that a year of film takes a year to watch. Looie496 (talk) 16:28, 4 August 2013 (UTC)

Almost certainly the technology exist to make it technically possible. (I even recall a science fiction story where everything and everyone was recorded 100% of the time.) But, as IP 70. says, it raises ethical questions. Would any parent consent to a child being filmed 24/7 from birth? Humans tend to find privacy pretty important Sounds a bit like The Truman Show --220 of ^Borg 16:54, 4 August 2013 (UTC)

The technology to record that much stuff is too recent to have been used to record an entire human lifetime...so no, it can't possibly have happened. It has, however, been done for shorter periods quite recently. For example, this excellent TED talk discusses recording all of the activity in an entire house as a child goes from birth to being able to talk. He tracked every single time his child made a noise when water was involved and got a beautiful series of audio snippets that showed how the child went from having no speech to being able to say the word "WATER" perfectly. SteveBaker (talk) 21:45, 4 August 2013 (UTC)

Classic link there from Steve, but it should be noted that it's the researcher's own child, so he has a lot more leeway. Raising a child so you can keep a camera on it for its whole life, so you can use it to extract data, sounds more like the subject of a Jodi Picoult novel than a real research experiment. If you did it at a university, you would have to go through an ethics committee, and they would be likely to block it, I would assume. Privacy is absolutely an issue, because at least the researchers would need to have access to the data, and they do not enjoy unfettered access to anyone's private world. They are not the CIA, after all, nor even anything close. The child, upon reaching almost any age, would have the right to withdraw consent, and that would simply make it pointless. Also it would have to be followed through by different researchers. I would say any research like this is a long way off. IBE (talk) 13:32, 5 August 2013 (UTC)

How would that help much in studying language development? Every parent in the world has a good idea of what their child hears, from the moment of birth to early childhood. That knowledge doesn't give them any insight on how the brain is structured, how sound is processed, the role of nature vs. nurture, whether a universal grammar exists, whether a critical period exists for language acquisition, etc. A better experiment would be to deprive a child of any language and see if they can still a language after childhood. This "forbidden experiment" has been done before, and the answer seems to be no: see Genie (feral child) and Victor of Aveyron. --Bowlhover (talk) 08:11, 5 August 2013 (UTC)

I think there is something to be gained by careful observation over time - and being able to go back and note carefully how speech transitions from one phase of development to the next would be valuable. For example, my son started off saying single words - then went to beautifully, grammatically correct phrases - then seemed to take a step backwards and start saying grammatically incorrect phrases before eventually correcting those errors and becoming fluent. The reason for this is that the first grammatically correct phrases were being memorized in one chunk - like they were a single word. Only later did he start trying to form new phrases - and having to actually master grammar. This tells us all sorts of interesting things - but having noticed that change, I was unable to go back and see how it started. There is no doubt in my mind that having a record of everything the child ever said would be useful in understanding the stages of development. But as Been Emotional said - it's an ethical nightmare to do that. Sure, researchers would love to have all of the episodes of The Truman Show on DVD - but that's not going to happen. SteveBaker (talk) 14:17, 5 August 2013 (UTC)

It occurs to me that we should mention Lifelogging.

This is the idea that people might voluntarily record everything that happens to them (to at least some degree). Some of those people attempt to record everything they hear and see (including their own voices) - and often other data like body temperature, heart rate, blood pressure and so forth. I suppose that if they chose to make that vast pile of recordings available towards the ends of their lives, it might tell researchers quite a bit. The problem, again, is that this is a relatively new idea - and the technology to store all of that data and to capture it using a portable device is still non-trivial. Certainly it's becoming possible though. The Google Glass headset can record sound and video and stream it continually via your cellphone to some kind of "cloud" storage system. I'm not sure the battery life of headset and phone are yet good enough to record everything on a 24/7 basis without recharging issues...and there might be times when cellphone access was patchy or unavailable - but with spare batteries and an acceptance that some data might be lost - this is becoming plausible. Another issue is that this is something that's really only being done by adults - so it'll miss that person's childhood language development - having a child wear something like this from birth is clearly unreasonable. SteveBaker (talk) 15:26, 5 August 2013 (UTC)

Do boron exists in asteroids?

I want to make a science fiction story that is based on polywell reactors for space energy, and so because it uses aneutronic fusion its fuel is hydrogen and boron. There is a lot of hydrogen in space, from ice electrolysis, but I never find any reference to boron in space either in asteroids or other planets 140.0.229.26 (talk) 15:55, 4 August 2013 (UTC)

See this paper for a review of the data on boron abundance in meteorites -- the best source of evidence. The answer seems to be yes, but not in very high concentrations. Looie496 (talk) 16:25, 4 August 2013 (UTC)

Where does the element boron come from? A few physicists from University of Illinois have already fact-checked and veried some of the claims in our boron article. Like those professional physicists, I (as a non-practicing physicist) have not ever heard much talk about stellar nucleosynthesis of boron. (Compare, say, hydrogen-burning, lithium burning, nucleosynthesis production of sodium, or iron... these were all homework problems in one astronomy-related class or other, and the details stick in my mind!) But I remember no discussions about boron! This is apparently because boron isn't commonly made by stellar nucleosynthesis - at least not by the major reactions. Boron is made by a more esoteric process, spallation of lithium by high-energy cosmic rays. As such, it's going to be much more rare everywhere in the universe: on earth, in asteroids, in stars. Nimur (talk) 17:07, 4 August 2013 (UTC)

Are you sure you're not thinking of Beryllium? 202.155.85.18 (talk) 01:17, 5 August 2013 (UTC)

I frequently think about beryllium, but in the instance above, my thoughts, discussion, and the source I linked to were related to boron. Some of that discussion also applies to beryllium - which is commonly produced by cosmic ray spallation, because (like boron) production of beryllium by stellar fusion requires a very low-probability reaction. I found this website from the folks across the bay: "how did the various chemical elements of the periodic table form?" Nimur (talk) 03:07, 5 August 2013 (UTC)

I have nothing to add here. I just really like the phrase "I frequently think about beryllium". You should get that on a T-shirt, or in Latin on your coat of arms. APL (talk) 11:27, 5 August 2013 (UTC)

I'm getting a mental picture for your story: A team of 20 mules, in spacesuits of course, hauling one of those asteroids away. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:55, 4 August 2013 (UTC)

Seems good enough. It seems that the story will be like a huge evil company controlling all boron mines on earth and the researchers found out about boron on space so they are trying to escape from that evil company monopoly, ohh wait seawater have a lot of boron.... Is there any way to extract boron out of seawater? 140.0.229.26 (talk) 00:42, 5 August 2013 (UTC)

Yes, but it seems the reason for it is to make safe drinking water, not to get the stuff.[13][14] Clarityfiend (talk) 00:56, 5 August 2013 (UTC)

As a matter of fact, it's also possible to extract pure boric acid from seawater by means of liquid-liquid extraction with ethohexadiol (formula C₃H₇CH(OH)CH(C₂H₅)CH₂OH) or similar chelating agents; however, for economic reasons this is normally done with concentrated salt-lake brines rather than seawater. 24.23.196.85 (talk) 01:31, 6 August 2013 (UTC)

Fooling Archimedes?

The other day I got into a debate with a friend concerning the Archimedes Principle. I raised the point that in some circumstances a carefully constructed object could be devised to fool the test - the interior of the object could simply be a combination of materials of different densities that balance out to the target density; for example, a hollow (ie: air filled) gold plated cube with just the right amount of lead applied to the interior walls. It makes perfect sense to me, but my friend seems to think that I'm horribly mistaken. Can someone here help settle the debate? 70.112.97.77 (talk) 16:05, 4 August 2013 (UTC)

Gold (19.30 g·cm⁻³) is denser than lead (11.34 g·cm⁻³). AndyTheGrump (talk) 16:09, 4 August 2013 (UTC)

To expand: the problem given Archimedes was to determine if a solid object was made of gold. Lead is much less dense than gold. You would need something denser than gold as well as lead to make something with the same density as gold. What you are saying would be right in other circumstances but the thief would have had to use something like osmium or platinum with the lead, which they didn't have at the time and are extremely expensive. Dmcq (talk) 16:13, 4 August 2013 (UTC)

Sorry, yes, I really should have consulted the periodic table before posting! Okay, so assuming that some denser material were available then it would be possible. Thanks! 70.112.97.77 (talk) 16:27, 4 August 2013 (UTC)

Sure, fooling the Archimedes test that way does indeed work. With some simple assumptions like the cavity is located so it does not change the object's center of mass.

In the particular case of fake gold bars, type tungsten gold bar or fake gold bar into your favorite web search engine. Tungsten is so slightly lighter than gold that simple tests have a hard time detecting it. For fake gold you'll need a metal that is both heavier and cheaper than gold (the periodic table leaves you little choice there), and can't easily be told apart from gold (electric conductivity, behavior in electromagnetic fields (see metal detector), doesn't give off radiation, etc). And someone will quickly figure out how to detect cavities inside a gold bar if those start appearing on the market - tap it, if it rings like a bell, well, uh oh... 88.112.41.6 (talk) 20:29, 4 August 2013 (UTC)

Above was mentioned center of mass... but a proper fake should also preserve the moment of inertia! Two objects with the same center of mass, but different moments of inertia, behave very differently. Just by swinging a hollow metal sphere around a little bit, or rolling it around... we could measure a difference, even if its average density and center of mass were perfectly matched to another solid sphere of the same outer dimension. I'd wager a gold brick that most people could even "feel" the difference, without rigorously measuring it.

We could enumerate other physical properties we might test: any imperfection in mimicking the correct thermal capacity or thermal conductivity won't make it past a few really "low-tech" tests. Nimur (talk) 22:30, 4 August 2013 (UTC)

The density of tungsten is very similar to that of gold and the bar sounds about the same, an easy way to find if a bar contains tungsten is to use a strong magnet, gold is diamagnetic, it repels a magnet, whereas tungsten is paramagnetic and so is attracted. See [15] Dmcq (talk) 23:28, 4 August 2013 (UTC)

I don't think "Archimedes' Principle" is the phrase you're looking for. That describes a property of buoyancy, not the "Eureka" moment where he realized that an object displaces a volume of fluid equal to its own volume. (And then used that to calculate an objects density, thus proving it was made from gold.)

Perhaps that's the "horrible mistake" your friend believes you've made. I don't believe that you could construct an object that would defeat the Archimedes' Principal. APL (talk) 11:24, 5 August 2013 (UTC)

It wouldn't have been possible at the time of Archimedes to make something with the density of gold out of other materials but it is quite easy to do nowadays. That's what another contributor was saying above about searching for tungsten gold bar, people have been swindled using imitation gold bars. Dmcq (talk) 11:51, 5 August 2013 (UTC)

And of course Achemedes could have been fooled too if the object in question was hollow. His approach would say "This is not gold" - even though it might well be. SteveBaker (talk) 15:14, 5 August 2013 (UTC)

That wasn't Archimedes' task - he was trying to see if the king was being cheated. A hollow space would be just as damning as an admixture. (Though I have a feeling that in such situations, the real answer is, come up with a great experiment and describe it to further your reputation, then tell the king whatever result he wants to hear!) Wnt (talk) 18:21, 5 August 2013 (UTC) oops, that was stupid, nevermind - he'd have weighed the crown and if it were all gold, that shouldn't be punished Wnt (talk) 19:45, 5 August 2013 (UTC)

Dmcq, yes. But my point was that constructing such an object would not defeat the "Archimedes' Principle", it would defeat the gold-test that Archimedes invented while taking a bath. They're not the same.

Archimedes is famous for more than one thing. APL (talk) 22:19, 5 August 2013 (UTC)

What kind of insect is this?

Orthoptera on a basil leaf.

What kind of insect (an orthoptera, I suppose) could this be? It was found in Southern Germany, on a basil leaf. Thanks. --Edcolins (talk) 19:13, 4 August 2013 (UTC)

It must be a female speckled bush-cricket. Could somebody confirm? --Edcolins (talk) 20:01, 4 August 2013 (UTC)

Yes, speckled bush cricket, female from the ovipositor curving up at the back. Richard Avery (talk) 06:29, 5 August 2013 (UTC)

Thank you! --Edcolins (talk) 19:29, 5 August 2013 (UTC)

Resolved

August 5

CNC milling?

I've been running one of these 3D printers for a while now, making and selling various items, particularly decorative figurines and keyrings, and I'm wondering about trying this milling thing, opens up opportunities for all sorts of different materials. Thing is, I'm not too sure on what sort of machine I'd want, wondering at what the limits would be on these 4-axis machines, whether they would be able to carve the shapes I'd want or not. then again, would that not involve attaching the item to the machine in some way, leaving a clear mark on it? I realise I don't actually know how these machines work at all, would it be possible just to upload a 3D model file into one and leave it to do all the work, or are things more complicated with these?

213.104.128.16 (talk) 11:23, 5 August 2013 (UTC)

As far as leaving a mark where it's attached, yes, you would typically have some finishing work to do after it come off the machine, to grind/sand it down and polish it. StuRat (talk) 12:55, 5 August 2013 (UTC)

(I also have a 3D printer - and also a couple of laser cutters - and I'm about to get into 3D milling machines too - so I've done quite a bit of research into them).

There are basically two kinds of CNC milling machines - 3 DOF and 5/6 DOF. "DOF" means "degrees of freedom" and describes the number of ways in which the cutting head can move.

• A 3 DOF machine can move in three axes just like your 3D printer can - but it can't create undercuts because it's removing material from above, not building it up from below.
• A 5 DOF or 6 DOF machine can also tilt either the milling head or the workpiece (or sometimes both) to reach underneath overhangs...it can make some things that even 3D printers can't make...but even a 6 DOF machine can't make some things that a 3D printer can make because the cutting head is kinda large and can't make it into some small spaces. A 5/6 DOF machine is basically a robot arm holding an electric drill with a milling bit.

So to do most of what you can do with a 3D printer really requires a 5 DOF or 6 DOF milling machine...the snag is that those things cost an absolute fortune! Many tens or possibly hundreds of thousands of dollars. 3 DOF machines are vastly cheaper - and there are designs out there to let you make them for about the same cost as a 3D printer.

The term "4 axis" is a bit confusing. Sometimes it refers to a 3 DOF machine with the fourth axis being the rotation of the milling bit itself (which is cheating!)...rarely it means that this is a 4 DOF machine - which would be able to rotate the workpiece around one axis (like a lathe maybe) with a 3 DOF machine doing the cutting. That wouldn't get you much further than a straight 3 DOF machine. Almost certainly, if this is something costing under $10,000 dollars then "4 axis" really means "3 DOF".

To attach the workpiece to the machine generally involves clamping small pieces to the platform - which might not leave a mark - but does result in you having a block of material at the base of your object that can't be milled and may have to be sawed off by hand. For large sheet materials, some CNC machines have a vacuum table that holds the part in place. Those only work well for relatively large parts. Yet a third alternative is if you can drill a hole inside the base of the workpiece and thread a bolt into it. You can then clamp the bolt, do the milling, then unscrew the bolt at the end.

In terms of working with these machines - they are very much like a 3D printer - you can upload a 3D model and (with appropriate software to plan the tool paths) just set the machine running.

To mentally visualize what a 3 DOF CNC machine can do, imagine you had a small electric drill mounted in your 3D printer in place of the hot-end extruder. Now imagine you lower the Z table all the way to the bottom (or raise the head all the way to the top - depending on how your 3D printer works) - then put a solid block of plastic into the machine. Now, this hypothetical 3D printer could cut away material, one layer at a time by moving the head back and forth over the parts of the plastic that you don't want anymore - then raising the workpiece (or lowering the head) a fraction of an inch and doing it again. The process is kinda like 3D printing in reverse.

If you have a website someplace with pictures of the things you sell, I could quickly tell you which of them a 3 DOF machine could make.

SteveBaker (talk) 14:07, 5 August 2013 (UTC)

You could try one of the milling services on the web, just like there are 3D printing services. That would give you a good feel for what you can get done and the prices are fairly reasonable. Have you tried sintered metal 3D printing? Dmcq (talk) 15:26, 5 August 2013 (UTC)

If you want a number of the same you could try casting in metal. and of course if they can be made from sheet metal there's all sorts of other options. Dmcq (talk) 15:35, 5 August 2013 (UTC)

3D printers that can do sintered metal aren't cheap - they rely on high powered lasers, plasma arcs or something similarly expensive and dangerous to sinter the metal - and that's a very difficult problem for a cheap design. My two 100 watt (made-on-the-cheap) lasersaurs cost $8,000 each in parts alone - and 100 watts of laser power is nowhere near enough to do metal sintering. So unless you're making a LOT of money doing this, you'll be stuck with paying someone else to make the parts on a machine you'll never be able to afford!

I know of one guy who made a cheap(ish) laser-sintering 3D printer - but his machine sinters wax laced with carbon...hardly metal...but you could use his wax objects in a lost-wax casting process.

But if you're thinking about making molds and casting objects in metal then another approach is to make a two-part 3D-printed mold and use that to cast metal objects. Obviously you have to have relatively low melting point metals and do your printing with the highest melting point plastic your printer can manage...sadly ABS and PLA (which are the two plastics that most 3D printers use) both melt at around 220C - which is unfortunate because metals like tin and lead melt at temperatures at least that high - so the mold would melt and be useless. But there are a few metal mixtures that melt at much lower temperatures - yet at high enough temperature to be useful for things like jewellery and key-fobs - sadly, some of those are toxic, so you have to be careful. Field's metal might be a good choice - it melts at 62C - Woods_metal#Related_alloys gives a list that includes all of the low-melting-point metals that I know of.

Another option is to make the object itself in plastic, then make a synthetic rubber mold from it and cast using that.

If you're interested in materials other than plastic - but would like to stick with 3D printing, this stuff should be of interest. It's made from wood-pulp and formed into a filament with a binder that most 3D printers can melt. Printed objects look and feel like wood (although without any grain). Some people are investigating using 3D printers with two heads - one loaded with light colored wood filament and the other with a darker version of the same material - and actually printing fake grain into the objects they make.

Fun stuff! SteveBaker (talk) 16:04, 5 August 2013 (UTC)

I was thinking of them sending off to a service doing sintered metal like for a milling service, sorry I should have made that clear. I'd have thought buying any machines would need to be carefully justified compared to sending off to a service which specializes in doing the work. Dmcq (talk) 20:22, 5 August 2013 (UTC)

Sounds good that wood material. Someone told me once they were going to use a wood effect paint and I thought they were joking - and they went ahead and got a nice wood effect with it! By the way for that wood material they can make it darker or lighter by using a higher or lower temperature when they melt it. Dmcq (talk) 20:38, 5 August 2013 (UTC)

Poison ivy for apes

Take a typical member of each great ape species and expose all of them to poison ivy. The human will get urushiol-induced contact dermatitis, but what about the others; are we the only species allergic to it, or will other apes also have problems? Neither article that I linked says anything about other species; I know that the plant doesn't cause problems for ruminants, but I know nothing about non-human primates. Nyttend (talk) 14:36, 5 August 2013 (UTC)

Having furry bodies helps them a lot. In order to get problems with poison ivy, it has to rub against your skin. A thick layer of fur makes that rather difficult - so I would expect that other great apes would have much less problems with the stuff than we "naked apes" do. The chemical involved (Urushiol) provokes an immune response that ultimately causes the symptoms. This article says "Deer and other animals can eat poison oak leaves without any apparent ill effect. Birds nest and find shelter in the plant. Only primates (humans, apes, chimpanzees, etc.) seem to have a reaction to poison oak." - so I guess you have an answer. SteveBaker (talk) 15:13, 5 August 2013 (UTC)

Drawback or limitation of modern synthetic theory of evolution or neo-Darwinism

What are some Drawback or limitation of modern synthetic theory of evolution or neo-Darwinism?

AmRit GhiMire 'Ranjit' (talk) 14:48, 5 August 2013 (UTC)

So, to be clear, you're talking about Modern evolutionary synthesis (which is also called "neo-Darwinism" and which is the way that evolution is understood in the last 50 years) - which (according to our article) "is still, to a large extent, the current paradigm in evolutionary biology."

The most obvious unresolved issue for me is abiogenesis. How did the first self-replicating molecule come about? Once such a thing existed, evolution became inevitable...but getting from "inert" chemistry to that is something of a leap. There are plenty of possible explanations - most of them plausible - but we don't know exactly which of them is true.

Our article Objections to evolution covers a huge array of objections that have been raised - but few, if any, are thought to be problematic by the vast percentage of scientists in the field - they are generally trivially easy to debunk using easily obtained evidence.

Evolution is one of the most solidly well-understood and verifiable theories in science - there really aren't "drawbacks" or "limitations" in the theory.

SteveBaker (talk) 15:06, 5 August 2013 (UTC)

I have to agree, there aren't really any drawbacks. There are disputes over the interpretation of such things as kin selection and selfish genes, but these are actually metaphysical disagreements--no one disputes the facts. Evolutionary psychology is ideologically controversial, but it's quite far removed from the modern synthesis itself. μηδείς (talk) 17:15, 5 August 2013 (UTC)

At least at the molecular level, the occasional impact of "Hopeful Monsters" shouldn't be dismissed entirely - things really do get abruptly reverse transcribed, recombined etc. to form dramatically new gene structures. Also, the theory doesn't really address the issue of heritable epigenetic change - the mechanisms making that possible are the products of evolution, but it means that the reaction norms of any given genotype are far more complex than previously imagined. Wnt (talk) 18:26, 5 August 2013 (UTC)

Who was Dr Price?

As a side issue to a question on the Language Desk, I found that the triple expansion engine (as used in the Titanic) seems to have been a British invention. According to History of British Shipping by Adam Kirkaldy, "Then Dr Price invented the triple expansion engine, effecting further economies in the consumption of fuel" (p.131). One was apparently fitted to SS Aberdeen (1881). Does anybody know anything about the ingenious Dr Price? His full name would be a start. Our Compound engine#History has a Spanish destroyer as the first in 1886, although it was built on Clydebank. Alansplodge (talk) 15:51, 5 August 2013 (UTC)

An article in The Quarterly Journal of Economics, "Substitution and Complementarity in Endogenous Innovation" (August 1993), discusses the rise of steam ships and cites:

• Harley, Charles K., "The Shift from Sailing Ships to Steamships, 1850-1890: A Study in Technological Change and its Diffusion," in Donald N. McCloskey, ed., Essays on a Mature Economy: Britain after 1840 (Princeton, NJ: Princeton University Press, 1971).
• Rosenberg, Nathan, Perspectives on Technology (Cambridge: Cambridge University Press, 1976). Ch. 11

I don't know whether either of these would mention Dr. Price, but they're the closest I come to any useful-seeming information so far. --some jerk on the Internet (talk) 21:00, 5 August 2013 (UTC)

I found many texts over the decades which parroted the line "hen Dr Price invented the triple expansion engine.." without any details. But the actual designer of the first successful triple expansion engine, used on the Aberdeen (1881) for high speed London-Capetown-Melbourne runs was "Doctor" Alexander Carnegie Kirk, See [http://books.google.com/books?id=m8TsygLyfSMC&pg=PA694&lpg=PA694&dq=the+aberdeen+1881+napiers&source=bl&ots=fXgwCpa8Kn&sig=A2yIROVbkJhIu-cUFElFlKDg-D4&hl=en&sa=X&ei=428AUqvXGurAyAHLloDAAQ&ved=0CFAQ6AEwBg#v=onepage&q=the%20aberdeen%201881%20napiers&f=false Biographical Dictionary of the History of Technology (2013) - Page 694. Maybe Price was one of his associates. Edison (talk) 03:52, 6 August 2013 (UTC)

Epilepsy: is there a limit to how often seizures can be photoinduced?

The way I understand it, flashing lights, even TV episodes, can induce epilepsy - occasionally even first seizures in children who haven't previously experienced them. Yet epileptic seizures are typically followed by a postictal state where no seizure can be induced. What I'm wondering is, does the photoinduction actually increase the overall tendency to have seizures on a consistent basis, and if so how much, or does it just affect the timing of seizures? In other words, is there a sort of "fuel for epilepsy" that gets consumed during seizures, and the lights merely provide a "spark"? (I'm picturing a hopefully thought experiment where an epileptic al-Qaeda member is locked in subbasement 25 under Diego Garcia, in a cell with a stunning light show going day and night... by what factor are his seizures increased over the long haul?) Wnt (talk) 18:38, 5 August 2013 (UTC)

Yes, there is a sort of "fuel for epilepsy". Electrical activity in the brain depends on ion concentration differences between the interior and exterior of brain cells, and those differences run down during a seizure. Afterward they are slowly reestablished by ion pumps. And yes, seizures can increase the probability of future seizures, by means of a phenomenon known as kindling. That doesn't always happen, but it can. Seizures can be triggered in anybody by electrically stimulating the brain -- that's what happens in ECT -- but light will only trigger seizures in people whose brains are particularly vulnerable. I don't know whether there is evidence that experiencing light-induced seizures increases the probability of future seizures. Looie496 (talk) 19:04, 5 August 2013 (UTC)

Very good point about the kindling model! I suppose the question actually breaks down into two separate conditions: (a) whether photoinduction can be used (perhaps together with isoniazid, thiosemicarbazide, harman, pentylenetetrazole, 3-mercaptopropionic acid, and/or strychnine) to help induce first seizures in non-epileptics and perhaps even to "kindle" long term epilepsy, and (b) what its effect is on those who already have longstanding epilepsy. I was only thinking about the latter above, but of course, depending on the person either might be relevant. Wnt (talk) 19:27, 5 August 2013 (UTC)

Human decontamination

Hello everyone,

I was wondering what cleansing agents were used for human radioactive decontamination? Do they contain more tensioactive agents than normal soaps, or special chelating agents like EDTA to help remove metallic radionuclides? Or perhaps do they contain some abrasive agents (as suggests the term Abrasivstoff in Dekontafix) to help remove the dead layer of skin and along with it any surface contamination? Regards, 141.30.214.203 (talk) 19:15, 5 August 2013 (UTC)

While we didn't go into too much details during my basic training two decades ago, the mantra seemed to be lots of soap and lots of water. Granted, we were mostly taught about chemical decontamination - but no mention was made that nuclear decontamination would be done differently. WegianWarrior (talk) 19:24, 5 August 2013 (UTC)

A quick search turns up [16] which seems to prefer dermabrasives (I actually didn't read much of this, but it looks useful). Wnt (talk) 19:31, 5 August 2013 (UTC)

Thank you for this paper; it looks like many solutions exist depending on the nature of the contaminant: EDTA for ⁹⁹Tc^m, soft abrasives, foams, detergents, etc. Always a pleasure to read the Ref Desk. Regards, 141.30.214.203 (talk) 19:49, 5 August 2013 (UTC)

Deep space travelers beware

What are some of the little known dangers of deep space travel? Are we attempting to solve them now or is that on the back-burner as we focus on inter-planetary travel closer to Earth?— Preceding unsigned comment added by 65.64.111.126 (talk) 19:21, 5 August 2013 (UTC)

Health threat from cosmic rays, IRWolfie- (talk) 19:53, 5 August 2013 (UTC)

Also the deterioration of the human body in low gravity, and the inherent dangers of travelling in an inhospitable vacuum vast distances from any help or hope of rescue or resupply, while completely dependent on high-technology devices for survival. -- The Anome (talk) 19:56, 5 August 2013 (UTC)

See also Effect of spaceflight on the human body and Space medicine. Dominus Vobisdu (talk) 19:58, 5 August 2013 (UTC)

And this is just for interplanetary travel. Deep space, in the sense of interstellar travel, also has the disadvantage that it is currently impossible -- and may well forever be impossible -- to traverse these distances in a human lifetime, or much vaster timescales in the case of intergalactic travel. Even travelling to the Oort Cloud, just a single light-year away in our immediate solar neighborhood, would present a major challenge.

Other than the creation of faster than light travel or teleportation, possible hacks that conform to current physical knowledge which have been suggested to sort this out include generation ships, sleeper ships, "nearly as fast as light" ships which would exploit relativistic time dilation, and the use of von Neumann probes or starwisps to carry and re-create human life from stored information or biological material over the course of thousands, or millions, of years.

Each of these may or may not be possible, and would in each case carry risks of their own. Unless something drastic happens to the human race in the next thousand years, I would expect someone's going to try at least one of these in that time. -- The Anome (talk)

Oh, and also don't forget the psychological effects of long-term isolation of tiny groups of people. -- The Anome (talk) 20:23, 5 August 2013 (UTC)

Ah, yes. The dreaded SPACE MADNESS! "I have had this ice cream bar since I was a child. People always trying to take it from me. Why won't they leave me ALONE!!!!" (Now I've got a hankering for some chocolate covered raisins. Popping out to the store... be right back!) Dominus Vobisdu (talk) 20:32, 5 August 2013 (UTC)

Yep. Space Madness (see here for TVTropes' take on this), a.k.a. the Pain of Space in "Scanners Live in Vain". -- The Anome (talk) 20:52, 5 August 2013 (UTC)

You asked for little-known problems, but most people responded with well-known problems. Here's some that might be a problem from years in space:

1) Nutrition. We may not know about every vitamin and mineral humans need. It's possible there's something vital that we run out of after years without eating real food.

2) Exposure to chemicals. Materials in the ship might give off fumes as they age, which are not filtered out, causing long-term exposure hazards. The same is true of packaging leaching chemicals into the water and food.

3) Instead of isolation, people might have problems being stuck with the same group of people for years. For example, who is having sex with whom could cause some serious tensions.

4) Lack of elderly care facilities. In a multi-generational ship, what do you do with people too old to care for themselves, especially those with dementia ?

5) Too small of a gene pool. In a multi-generational ship, inbreeding will eventually be a problem unless, say, millions of frozen sperm and eggs are shipped with them to be used for reproduction.

6) Freezer burn. If food, sperm, eggs, or even people are frozen, then slight changes in temperature, over time, can cause degradation. StuRat (talk) 21:26, 5 August 2013 (UTC)

Solution for (4) and maybe (1) too: Soylent Green. Clarityfiend (talk) 22:35, 5 August 2013 (UTC)

There may be social problems with a multi-generational ship, too.

In books this is always represented as a total breakdown of civilization and people forgetting that they're on a ship, but it wouldn't have to be that drastic. What if the people who arrive at the destination know full well they're on a ship, but don't want to abandon their home by going down to the planet? (Imagine giving up your home and roughing it on an unknown world because your great-great-great-grandfather agreed to be a pioneer!)

That's just one example. Just about any kind of social breakdown we have here on Earth would be worse if it happened on a generational ship. APL (talk) 08:51, 6 August 2013 (UTC)

Genuine inquiry here: I remember one novel detailing exactly the first scenario you describe above; who else touched upon it? Snow (talk) 09:11, 6 August 2013 (UTC)

A risk I would worry about would be being passed by later, more advanced ships. This has been explored by a number of sci-fi writers, so maybe it's not all that "unknown", but it would sure suck to go through all that trouble only to get to the other planet and have people already there who tell you "Oh yea, We invented the Warp Drive about a week after you left." APL (talk) 08:51, 6 August 2013 (UTC)

Are you sure that's really the worst case scenario? Mightn't it be worse to hear that they invented it last week? Snow (talk) 09:50, 6 August 2013 (UTC)

Dust. No, seriously, very much a problem and one of my favourite examples of how poorly understood the rigors of space-travel are and how inadequately the complexities are treated in popular media and amongst amateur enthusiasts. There's a lot of matter out there and when you're traveling at the kinds of velocities that we would almost certainly be looking at for exploration beyond the solar system, it only takes a very, very small amount of it to annihilate a craft of any realistic proportions upon collision. As to your second question, much thought has been given to how we might tackle the herculean task of interstellar travel, with most of the better-regarded proposals originating from the middle of the last century and having been debated (with regard to which is most feasible) by engineers and scientists from a wide-array of disciplines ever since. However, as regards actual practical efforts (or indeed even efforts to generate general support for such a venture), your assumption is quite correct; the priority in terms of research an expenditure has been overwhelmingly on "local" space travel (and indeed, extremely local), and there's increasingly less support for even these efforts in terms of both public support in leading industrial nations and financial support from the governments of same. <tangent of questionable appropriateness regarding question> You know, every time I've ever heard the query "If you could have a conversation with anyone, living or dead, who would it be?", one of the names that always comes to the top in my mind is Carl Sagan, but at this point I don't think I could look him in the eye, we've all collectively dropped the ball so poorly as regards vision for the future of our species outside of Earth. </tangent> Snow (talk) 09:00, 6 August 2013 (UTC)

If you are a telephone sanitizer, the risks are well know, just not to you. See: [[17]]. Dominus Vobisdu (talk) 09:13, 6 August 2013 (UTC)

There are also a possibly infinite number of unknown unknowns in Parts Unknown (might help to read the transcript in the description, but only maybe). InedibleHulk (talk) 09:51, August 6, 2013 (UTC)

On a generational ship, would there not also be a risk of a population explosion and therefore using up the resources too soon? 184.147.136.32 (talk) 11:20, 6 August 2013 (UTC)

August 6

Which human ancestors invented fire?

In the course of evolutionary history ,Which human ancestors invented fire?

AmRit GhiMire 'Ranjit' (talk) 00:26, 6 August 2013 (UTC)

Probably Homo erectus: see Control of fire by early humans. AndyTheGrump (talk) 00:30, 6 August 2013 (UTC)

And that would be "discovered how to use fire", not "invented". StuRat (talk) 00:39, 6 August 2013 (UTC)

Type of solid

What is the term for a covalent network solid that melts by ionising? For example, -ABABA- → AB⁺ + ABA^-. Plasmic Physics (talk) 04:48, 6 August 2013 (UTC)

Generally, covalent network solids (like diamond, silicon, Bakelite, etc.) melt WITHOUT ionizing. Can you give an example of a covalent solid that ionizes as it melts? 24.23.196.85 (talk) 04:56, 6 August 2013 (UTC)

I'm certain that some of the hyperfluorinated metals exhibits this sort of behavior, though I can't seem to find a good example at the moment. Plasmic Physics (talk) 05:03, 6 August 2013 (UTC)

Metal fluorides are ionic solids, not covalent. 24.23.196.85 (talk) 05:42, 6 August 2013 (UTC)

Not generally, that is an over-simplification taught in secondary schools, just like "the conjugate of a weak base, is a strong acid" which is not strictly true either. See aluminium fluoride for an example of a covalent metal fluoride. Plasmic Physics (talk) 05:51, 6 August 2013 (UTC)

Correct, but AlF₃ breaks up into neutral molecules upon melting, not into ions. 24.23.196.85 (talk) 07:44, 6 August 2013 (UTC)

Indeed. However, I did not give it as an example of the substance in question, but only of a non-ionic metal fluoride. Plasmic Physics (talk) 08:36, 6 August 2013 (UTC)

Some sort of homoassociation of the parts? DMacks (talk) 05:56, 6 August 2013 (UTC)

Perhaps. Would it be a two step process, whereby the solid breaks into individual monomeric molecules, followed by their homoassociation? Plasmic Physics (talk) 07:05, 6 August 2013 (UTC)

Is solid oxonium hydroxide stable under pressure, or does it require an applied electric field? I wonder how the density would be different from ice. Plasmic Physics (talk) 07:14, 6 August 2013 (UTC)

American plague

European diseases killed many native americans, why did not american diseases kill the europeans? — Preceding unsigned comment added by 128.214.48.186 (talk) 09:59, 6 August 2013 (UTC)

The Straight Dope tacked this thoroughly. 184.147.136.32 (talk) 11:28, 6 August 2013 (UTC)