Wikipedia:Reference desk/Archives/Science/2011 May 28

= May 28 =

Tornadoes and bodies
There are still about over 100 missing people from the Joplin tornado. When the Governor was on CNN, he noted that one of the problems about giving relatives access to the morgue is that some/many/most of the "bodies" were not identifiable in their current form. (I think he specifically mentioned "pieces". We recall this was also the case after 9/11.) Is it a known after effect that pieces of bodies are discovered strewn about the landscape, sometimes at great distances from the actual event? (They found a child some 80 feet or so from his house in a small lake.) Are whole adult bodies likely to be carried far (say a mile or more)? Is there anything written about this phenomenon, assuming it exists? Bielle (talk) 05:01, 28 May 2011 (UTC)
 * The tornado leveled buildings, whole neighborhoods really, carried x-rays 70 miles (112 km) away and a receipt 525 miles (845 km) away. It sucked a teenager out of his seatbelt and out of the sunroof of an SUV. Dismembering a body seems minor by comparison. Stormchasers claims in 2006 one person survived a quartermile (0.4 km) trip in a tornado. Rmhermen (talk) 15:20, 28 May 2011 (UTC)
 * The receipt story has been withdrawn - so 228 miles is the debris record still from an earlier tornado. Rmhermen (talk) 17:51, 29 May 2011 (UTC)
 * A popular press story after the 1947 Glazier–Higgins–Woodward tornadoes was that two people known to be together at the time of the tornado were later found dead 3 miles apart. Now, newspapers back in the day (as with the media today) are known to creatively exaggerate tragic stories, so whether this actually happened is up for debate. But it is known that tornadoes can carry much heavier debris than a human. I have a book here (The Handy Weather Answer Book by Dr. Walter Lyons) which lists some quite interesting cases:
 * A church steeple carried 15 miles
 * An 800-pound ice chest carried 3 miles
 * A 13-ton fertilizer tank blown or rolled 3/4 of a mile
 * A motel sign that was carried from Broken Bow, Oklahoma to Arkansas, a journey of at least 10 miles.
 * In addition, the terminal velocity of the average human is around 120 mph. I can't find any citations for specific cases, but in theory updraft speeds in tornadoes can exceed 200 mph. Therefore it is not unreasonable to assume that humans can be carried by a tornado indefinitely, until it weakens or the person is centrifuged out of the updraft. - Running On Brains (talk) 01:43, 29 May 2011 (UTC)

Would perfect cell replication lead to immortality?
I asked a similar question here a couple of years ago and posters thought I was referring to the Ship of Theseus puzzle – that is, whether an object, such as a ship, when it is repaired so many times that no part of the original remains, can be said to be “the same thing”. This is an interesting notion but not the subject of my query. I am thinking of whether there can be forces affecting an organism that somehow do not affect it purely on a cellular level, but only on larger scales. In this case, perfect cellular replication would not forever protect the body from the depredations of old age, though they it would certainly delay it.

As we age, our buttocks, breasts, faces, stomachs and so on begin to sag from decades – long exposure to gravity. Can this morphology be described completely at a cellular level? Or is it the case that there are forces that can work on us holistically. If new cells replace old ones without error, will that negate macroscopic effects like a bent spine? On an analogous level, there is an effect called metal fatigue, which weakens steel in structures where it is under stress for long periods of time. Microscopic cracks appear, and a plane’s wing can snap, for example. The replacement of molecules and atoms in the structure with other ones would not provide a remedy, that is, it would not remove the cracks which form from tensions on a larger scale. Likewise, I am wondering if a completely reductionist approach to the cellular problem would provide us with immortality (pending external trauma). I have a feeling that it would not. You could replace cells in the spine incrementaly. But it would probably still become bent with time, as such effects are not engendered at a cellular level, but at a mechanical level and on a larger scale. Myles325a (talk) 10:19, 28 May 2011 (UTC)


 * There is such a thing as cellular senescence. New, non-senescent cells don't automatically mean new extracellular matrix - an old person with new bone cells would still have osteoporosis, at least for a time.  But with the notable exception of teeth I would think most ECM would be replaced in time.  In the end, however, biology is not susceptible to theory - one must do the experiment and see what happens. Wnt (talk) 15:37, 28 May 2011 (UTC)
 * "biology is not susceptible to theory" Really? you might like to tell the publishers of the Journal of Theoretical Biology. I agree that ultimately you do need to do the experiment - but theoretical/mathematical analysis can get you a very long way in telling you exactly which experiment to do. Equisetum (talk &#124; email &#124; contributions) 21:51, 28 May 2011 (UTC)
 * Perhaps I exaggerated. Theory applies when we look at what happens with large numbers of organisms - evolution, population genetics, taxonomy.  It applies with small systems that are essentially chemical in nature - binding of a ligand to a receptor.  It applies in a handful of unusually consistent systems, such as DNA recombination and linkage mapping or protein translation.  With the caveat that the biology can still bite back and cheat the equations even in these circumstances (e.g. epigenetics, assortative mating, allosteric regulation, recombination hotspots, RNA editing). Wnt (talk) 01:40, 29 May 2011 (UTC)


 * It would be a weird sort of immortality. Our memories are stored in the synaptic connections between brain cells -- a typical cell makes on the order of 10,000 connections to other cells, each with an individually calibrated strength.  Most types of brain cells don't replicate, but even if you could cause them to do so, it is inconceivable that they could copy the strengths of all the connections.  Thus by the time you have replaced all the cells in the brain, you would have lost all of its memory.  I don't think immortality is very useful if it implies total amnesia. Looie496 (talk) 01:55, 29 May 2011 (UTC)


 * For an exploration of greatly increased lifespan and memory loss, I recommend the occasionally disturbing science fiction book, Capitol, by Orson Scott Card. An interesting example of the subgenre which starts with a piece of new technology, then explores the implications for society and the uses to which it is put. 86.164.164.27 (talk) 22:35, 30 May 2011 (UTC)

VLT (Very Large Telescope) HD Timelapse Footage
What are the "shooting stars" I see starting around 1:30 in this video. They're obviously not meteors since this is time-elapsed video. Are they planets? I didn't think planets moved this fast in such a short amount of time. Also, there seems to be a lot of them given we only have 7 or 8 other planets in the solar system. Are they air craft or satellites? A combination of the above? A Quest For Knowledge (talk) 13:14, 28 May 2011 (UTC)


 * Some could be aircraft but most likely all of them are satellites. Definitely not planets or meteorites.--Shantavira|feed me 14:04, 28 May 2011 (UTC)


 * Concur about planets and meteors. Planets aren't going to move visibly against the background stars (unless you're looking very closely) over the course of just one evening; they definitely don't go flying across the sky.  Meteors might last for a second or two; in a time lapse movie like this one, they'd appear as a streak that blinked on for one frame and then disappeared again; you wouldn't get them visibly moving across the screen like the objects you're seeing here.
 * Satellites are one possibility, but it would be somewhat unusual for them to be so much brighter than the surrounding stars. The fainter trails certainly could be satellites, but my money is on most of those bright trails being aircraft.  If you freeze-frame the video at just the right point in time, you can pick out periodic variations in brightness (the trail takes on a 'dashed' appearance) as the navigational lights flash on and off. TenOfAllTrades(talk) 22:43, 28 May 2011 (UTC)

"Wet" disposal of acetone peroxide. Also, intercepting suicide bombers
Disclaimer: I am NOT a bomb-maker or terrorist, and do NOT plan to "try this at home". ASIO, please leave me alone, thanks :-). Or at least wait until I get my Pyrotechnician's licence or Explosives engineering degree. That sorted? O.K. Acetone Peroxide has been commonly used by terrorists. It is extremely volatile, and can potentially explode at the slightest rubbing or tapping. As such, I assume disposal would be a dangerous exercise. My question is: Has anyone discovered a way to "chemically" neutralize acetone peroxide? If not, does that mean it isn't possible? What techniques would be used to remove something so volatile, other than detonating it on-site or having robots remove it? As a seperate (spooky) question, can anyone point me to research / theory on "live" interception of an identified or suspected suicide bomber? The Death of Jean Charles de Menezes clearly shows what can go wrong in such cases. This is an example of a successful live intercept, though clearly the bomber was "lucky" not to be shot. (Later reports suggested his bomb vest may have been faulty). Here is another - again, circumstances were right, and (in this case) the would-be bomber compliant with demands by the intercepting security personnel. Obviously, most suicide bombers will detonate themselves when cornered by security (as has happened on many occasions). Logic dictates that "live intercepts" are most likely to be possible if the bomber can be confronted in a "clear" (non-crowded) area with good cover for the interceptors. Enough rambling. Any sources you can point me to who have examined this topic? Any Wikipedians with expertise in the matter which they are free to share? 203.45.95.236 (talk) 13:16, 28 May 2011 (UTC)
 * I would think that the methods used to deal with diethyl ether peroxide (from old diethyl ether) might work. But I don't see why anyone would use them rather than explosion or simple dilution. Wnt (talk) 15:34, 28 May 2011 (UTC)
 * Detonating the device is usually the safest method. Would you detonate grains caught in the threads of the closure while trying to access the explosive leading to the whole thing going off? Would your chemical agent by capable of fully reaching all of the powder packed at an unknown density into any randomly shaped container? Would the force of injecting the reagent set of a friction-triggered explosion? Would the heat of reaction cause a partial detonation of the unreacted material? Is the explosive a mixture of several different explosive compounds requiring different treatments? Is the bomb created by Hollywood villains with access to motion sensors, electrical feedback circuits, hidden timers, etc.? Rmhermen (talk) 16:18, 28 May 2011 (UTC)
 * I'm no bomb expert, but when I said "dilution" I was thinking "... at the end of a fire hose", assuming you'd found an unsealed container somewhere. Wnt (talk) 02:41, 29 May 2011 (UTC)

Explosive detection will give you some insight in how you can detect a suicide bomber. Apprehending them is another story.Sjö (talk) 09:01, 29 May 2011 (UTC) But when I reread your question I see that it's about the apprehending part. Ignore what I wrote.Sjö (talk) 09:07, 29 May 2011 (UTC)

Acetone peroxide (TATP), like most organic peroxides, reacts with KMnO4. In small quantites this reaction is not explosive (actually with ~100mg TATP it was very slow), also TATP is a bit hydrophobic. -Yyy (talk) 07:44, 31 May 2011 (UTC)
 * This is not a safe way to handle a bomb. Or to mix those chemicals at all. 75.41.110.200 (talk) 23:37, 31 May 2011 (UTC)

dsp3 and d2sp3 hybridisations
I know that sp3d and sp3d2 are not same as dsp3 and d2sp3, but I am unable to get clarity. Can you please give few examples of dsp3 and d2sp3 hybridizations? --Krishnashyam94 (talk) 16:28, 28 May 2011 (UTC)


 * Where does it say they're not the same? --Ben (talk) 16:44, 28 May 2011 (UTC)


 * I think it has to do with which initial orbital is hybridising into the final orbitals. Example, in sp hybridisation, the s orbital splits between s a nd p. Since the s orbital split, it is listed first. I could be wrong, it just an idea. Plasmic Physics (talk) 23:19, 30 May 2011 (UTC)

impact induced colour change in clay
While walking this morning I saw two men digging a hole in the ground. the material they were digging in was a typical gray coloured clay, but what got my attention was the instant and dramatic colour change of the clay as it was struck by the digging tool. As it was chopped the newly exposed surface of the clay that had contacted the tool turned immediately to red. Clay which had been dug the day befor had lost almost all of the red patches indicating perhaps oxidation of some mineral in the clay. Anybody know anything about that? 190.148.136.174 (talk) 18:00, 28 May 2011 (UTC)
 * Rusty tool? Cuddlyable3 (talk) 20:57, 28 May 2011 (UTC)

No. absolutely not. I stood and watched those guys which did not exactly endear me to them and I looked closely at the tool. No visible rust. Hence, It got my attention.Phalcor (talk) 21:17, 28 May 2011 (UTC)

Also if the colour had been rust deposition, then the colour would have remained which it did not. Phalcor (talk) 21:26, 28 May 2011 (UTC)
 * Here red is the normal color of the soil, gray is caused by diffusion of light in tiny cracks a result of Desiccation --Digrpat (talk) 23:13, 28 May 2011 (UTC)


 * I can't make sense of the description. You said the clay turned red immediately after it was exposed and then faded to gray over time, but from the description it seems that the clay may have been red before it was exposed.  How can you know what color the clay was before the tool sliced into it? Looie496 (talk) 04:18, 29 May 2011 (UTC)


 * A red mineral that oxidises to black when exposed to air is probably an iron rich clay. Iron has red and black oxides. Roger (talk) 11:26, 30 May 2011 (UTC)

pf plants
what are pf plants — Preceding unsigned comment added by Anmolv2 (talk • contribs) 18:42, 28 May 2011 (UTC)


 * I presume that you are talking about pulverised fuel plants, which involve the burning of coal that has been crushed into fine particles before combustion. Mikenorton (talk) 18:56, 28 May 2011 (UTC)

Is this 100% whole wheat bread?
This Whole Wheat bread doesn't say 100% whole wheat, so I assume it's not, but I'd like to know for sure. Ingredients: Whole wheat flour, water, oat fiber, wheat gluten, honey, 2% or less of the following: steel cut oats, corn flour (is this it?), cracked wheat, brown sugar, molasses, soybean oil, cultured wheat flour (and this?), soy lecithin, etc. Thanks. (Hmm, no refined sugar, but sugar nonetheless.) 66.108.223.179 (talk) 20:14, 28 May 2011 (UTC)


 * Scientifically, that's clearly not 100% wheat. My guess is that you want to know the answer from a public policy/regulatory standpoint, i.e. whether, by convention, bread with certain ingredients (in certain proportions - an important consideration that you don't specify) can be called "100% whole wheat bread".  This doesn't seem like the right reference desk for that question.  Maybe RD/Misc?  -- Scray (talk) 04:47, 29 May 2011 (UTC)


 * "The exact composition of whole wheat bread varies from country to country and even within one country". See whole wheat bread.--Shantavira|feed me 05:44, 29 May 2011 (UTC)


 * Given that it has gluten, the flour used could well be 100% whole wheat flour (minus the bit of cornflour, which is probably used as a thickener or binder). Without gluten, you usually need some white flour in the mix, or the bread will be crumbly. (There may be substitutes for gluten, I don't know, I'm not a baker). Obviously, "whole wheat" refers to the flour used, not the bread as a whole. Making bread from wheat or flour alone would be impossible, unless you consider flatbreads like Matzo to be "bread". Eliyohub (talk) 13:32, 29 May 2011 (UTC)
 * I'm not sure I understand your point, don't all wheat products have gluten in them?  Besides that, if something is listed separately on the ingredients list, it usually means they're adding it separately. APL (talk) 02:18, 31 May 2011 (UTC)
 * There is such a thing as gluten-free bread, I believe. But what I meant is, if you want to make bread without any white flour (i.e. just wholemeal flour) you need to add extra gluten (in addition to that already present in the flour), as in the bread above, to avoid crumbly bread. I was saying that the addition of extra gluten makes it possible to use 100% whole wheat flour. If you don't use extra gluten, you need some white flour in the mix. Eliyohub (talk) 10:28, 31 May 2011 (UTC)
 * Oh, I see what you mean. Sorry. APL (talk) 15:58, 31 May 2011 (UTC)


 * I think the usual definition for "100% whole wheat bread" is that "100% of the flour in the bread is whole wheat". This clearly isn't true here, due to the oat, corn, and (non-whole) wheat flour added.  However, it does appear to be mostly whole wheat.  I'd say that looks to be a reasonably healthy bread you've got there, as opposed to some breads which are just white flour, with brown dye and a smidgen of whole wheat tossed in so they can say "made with 100% whole wheat". StuRat (talk) 17:41, 29 May 2011 (UTC)


 * Sorry, I missed the "cultured wheat flour" bit. You are correct, there is a bit of white flour in this bread, it seems. As I said, making 100% whole wheat bread is tricky, unless you don't mind crumbly bread. I'd suggest comparing the "dietary fibre" content (on the "nutrition information" chart) with other whole-wheat breads, given that it would be the main reason you'd want whole-wheat bread, methinks. Eliyohub (talk) 10:58, 30 May 2011 (UTC)

Nintendo 3DS
I just saw the Nintendo 3DS with my own eyes, and was convinced I could see what my brain interpreted as 3D images on a 2D screen, without any special equipment. How does this work? I presume it has to be some artifact of the physical screen, diverting light from the screen to my eyes in different angles, but how does it actually work? J I P &#124; Talk 20:28, 28 May 2011 (UTC)
 * See the article Parallax barrier. Cuddlyable3 (talk) 20:55, 28 May 2011 (UTC)
 * Unsurprisingly the obvious place you'd expect to find discussion of the Nintendo 3DS screen and 3D effect i.e. the Nintendo 3DS article itself, which the OP apparently already found themself, links to that article as well as Autostereoscopy. Nil Einne (talk) 07:41, 29 May 2011 (UTC)


 * It uses a Lenticular lens. (A type of Parallax barrier.). You've seen these before. If you've ever seen a birthday card or cereal box that was 3d, or that showed different pictures depending on the angle you held it, chances are it had a lenticular lens over the image.
 * You didn't ask, but everyone always wonders : Yes, they do make TVs with this technology. They're absolutely horrible. I honestly don't know why they bother manufacturing them.
 * Lenticular displays are very,very particular about viewing angle. You've pretty much got to be exactly 90 degrees to the screen. Move your head two inches to either side and the effect is ruined.   This works well on a device that you hold in your hand, because you instinctively adjust the angle until it looks good without even thinking about it. (Like the greeting cards.)    But, any time you see one of these lenticular TVs being shown off, there's a giant sign explaining that the future is here and now you don't need glasses to see 3d, and also there's a little "X" on the floor made of masking tape. And you have to stand exactly there to see the 3d.
 * APL (talk) 06:02, 30 May 2011 (UTC)
 * So it's like one of those pictures that changes when you view it from a different angle, like what you see on birthday cards and comic book covers? I did notice I had to hold it at an exactly perpendicular angle from my face to get the effect to work. J I P  &#124; Talk 17:10, 30 May 2011 (UTC)