Wikipedia:Reference desk/Archives/Science/2015 September 18

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September 18

Who designs pharmaceutical capsules?

Not the contents, but the exterior - the colours of the casings, and any symbols that appear on them. Are they designed strictly according to certain guidelines, or is there some creative latitude? If the latter, are industrial designers employed for the purpose?

Thanks

Adambrowne666 (talk) 01:47, 18 September 2015 (UTC)

Just to get things started: People like Jill Morton, "a Color Professor whose primary focus is on color psychology and branding", see for example her website's "The Color of Medications or "Color Consultation - Healthcare & Pharmaceutical Products". ---Sluzzelin talk 02:20, 18 September 2015 (UTC)

The miracle of two concave mirrors

I have heard, but not seen this phenomenon, where two concave mirrors kept face to face with a hole in upper one creates the 3D image of the small object kept inside. Is it real enough to fool human-eye?

But recently I have read in an online commercial that the things work only "...when looked from proper angle...". Does that mean that the hologram will not work if looked just from everywhere? 27.255.191.189 (talk) 02:43, 18 September 2015 (UTC)

It's not a miracle It's a real image projected by the concave mirrors. This page explains in some detail how this trick, and others like it, work. --Jayron32 02:54, 18 September 2015 (UTC)

I'm getting a 404 on that external link, Jayron. {The poster formerly known as 87.81.230.195} 185.74.232.130 (talk) 13:25, 18 September 2015 (UTC)

Sorry, It was working yesterday when I linked it. I'll try to find a replacement. --Jayron32 14:11, 18 September 2015 (UTC)

Anyhow, the same link I used yesterday is now showing as a 404 today. Try This page instead; the last example is the floating coin illusion. It has a nice Ray tracing diagram of the illusion at the end showing how the image is produced. --Jayron32 14:20, 18 September 2015 (UTC)

Where are all the figures (A-H) mentioned in that article ? StuRat (talk) 04:04, 18 September 2015 (UTC)

I have seen it with my own eyes in a science museum. At a glance the object looks real, it looks like you can reach out and touch it. And yes it only works from a fairly narrow angle, if you look from the top or the side the image "break", you basically have to be looking "into" the hole on enough of an angle to see the whole object, but not too much of an angle otherwise you see the actual object sitting at the bottom. Vespine (talk) 04:05, 18 September 2015 (UTC)

Are you talking abot this? Clam shell mirrors: Floating coin illusion. --Aspro (talk) 13:35, 18 September 2015 (UTC)

Can I mine Gold of gilded objects?

If I have thousands of gilded objects, can I just scrape off the layer of Gold off it and mine Gold? --Hijodetenerife (talk) 04:56, 18 September 2015 (UTC)

That wouldn't be considered mining gold under most definitions. Anyway, even with thousands of gilded objects, you'd likely find the amount of gold you recover still isn't worth much, in fact probably far less than the combined worth of the objects before you scraped off the gold. (Probably even less than the worth after you scraped off the gold.) Nil Einne (talk) 05:11, 18 September 2015 (UTC)

Gold plating can be very thin, gold can be plated in layers as thin as a micron or thinner, at that thickness, you could gold plate a house for a few hundred dollars worth of gold. While your gold plated objects may have thicker coatings (and likely do), it still wouldn't be worth it to do so. As noted by Nil Einne, the value of the objects as objects is likely much greater than the melt value of the gold on them itself. --Jayron32 10:34, 18 September 2015 (UTC)

There is a TV advert where they try to sell you reproductions of famous gold coins. The advert goes to some trouble to tell you how pure the gold is - and how much the value of gold is increasing - and even tells you the amount of gold (betting, I presume, that nobody in their target demographic knows how much a milligram is!)...the total value of the gold on one of those $19.99 (limited time only - limit one per family!) is around 2 cents.

Gold is capable of being made VERY thin. Sheets of "gold leaf" that you use for gilding things is less than $1 per sheet - because the gold in it is so incredibly thin. SteveBaker (talk) 20:00, 18 September 2015 (UTC)

And how else can I get the gold out of the objects without scraping them off or loosing value? And if it is worth or if it isn´t worth should decide my free time, not the worth of the Gold...--Hijodetenerife (talk) 04:19, 19 September 2015 (UTC)

No one here knows the value if your free time. However if you are able to scrape gold off items, you likely have working limbs, so you could probably find something better to do with your limbs which would make more money so the utility of scraping gold of items for money is still suspect. Particularly since you are able to ask questions here on the RD and in English.

And for many items, it's impossible to remove the gold without seriously damaging the value of the item, because the value of the item will be strongly dependent on it being as close to original condition as possible. This is particularly the case for antiques, which I assumed given you referred to gold gilding rather than gold plating or tinning.

Only for a small number of items with gold gilding which are only worth as much as the materials that make them is it going to make sense in any way to seperate the different materials. However, as I already mentioned, even in those cases there's a good chance the copper or iron or whatever else that makes up more of the material is worth more than the gold. Scraping of the gold isn't going to give you much more value in gold, and it probably isn't going to significantly increase the value of the other materials, so again concentrating on the worth of the gold is likely missing the point. (I'm not an expert on metal recycling but I presume most either have a way to remove the gold, or it doesn't matter.)

If the item is primarily wood or stone or plastic with little other metal, perhaps the gold really is the most valuable thing that is theoretically recoverable from the item, but you still have to consider the earlier caveats. I.E. the likelihood you could sell the item on eBay or whatever for much more than you will ever recover in gold and note this doesn't have to be a big amount, since if you can sell the item for $1+shipping, you will still be making more than $0.0001 or whatever the recoverable gold is worth. And the likelihood that there is something else you could be doing that will make a fair amount more money.

There are also other caveats not really touched on. Scraping off gold will require some tool which will wear out, unless you're just grabing rocks or something, the cost of this tool will probably end up being more than the gold you recover. You have to find a way to process the gold you recover in to usuable form, or get someone to do it for you which is difficult when you have so little unless you want to do stuff which is dangerous and probably illegal. Plus does this scraping off result in you eating more, RSI, etc? The cost of any of these will likely be significantly higher than scraping off the gold.

Nil Einne (talk) 05:58, 19 September 2015 (UTC)

Medical advice

If a patient calls and tells an office staff they are going to stop taking a controlled substance cold turkey and the office staff says I don't think you should do that without talking to a doctor, would you consider this giving medical advice? — Preceding unsigned comment added by 2607:FB90:1390:6A8B:0:1C:FD38:F601 (talk) 10:36, 18 September 2015 (UTC)

That's not only medical advice, it's the epitome of medical advice banned under our stricture. You're talking about a patient talking to the staff of his or her medical practitioner, and anything we say regarding that communication qualifies as "medical advice." Ethically, we have to let the parties to this communication work it out among themselves, because all we know about the situation is what one party to the communication is telling us. Were that not the case, we'd still be forbidden to give any advice to either party that is medical advice. loupgarous 23:30, 22 September 2015 (UTC)

E = M C squared

Am I correct in assuming that "E = M C squared" is a meaningless phrase on its own without context? Like, if you presented that to a scientist before Einstein invented it, just "E = M C squared" on its own with no context, they'd be like "I don't get it"? Or does it have some inherent understanding condensed into it? — Preceding unsigned comment added by 117.178.158.168 (talk) 15:23, 18 September 2015 (UTC)

This equation is discussed in Mass–energy equivalence. ←Baseball Bugs ^{What's up, Doc?} carrots→ 15:41, 18 September 2015 (UTC)

That doesn't really answer the question I asked though. It's like saying "Here's an article on Cats" in response to a specific question asking why elderly cats run around the house at night yowling in empty rooms. 117.178.158.168 (talk) 15:49, 18 September 2015 (UTC)

Your first assumption is correct. Einstein discovered (not invented) the relation expressed in the famous equation:

$E=mc^{2}$

which is meaningful only when the symbols E, m and c have been defined. The Wikipedia article Mass–energy equivalence will definitely help understand this important physical relation. 84.209.89.214 (talk) 15:54, 18 September 2015 (UTC)

Thanks for confirming that! I was mostly curious because in films and cartoons and other popular culture they just show scientists or Einstein writing down that one equation on an empty blackboard. I'd seen it portrayed this way so much I was starting to wonder if the equation was something amazing in of itself. Anyway, thanks for your help! 117.178.158.168 (talk) 15:58, 18 September 2015 (UTC)

The equation is one of the most famous equations in physics. It is not necessarily the most important equation, or even the most important equation developed by Einstein. It is probably more famous than his other equations because it is simpler. Also, if one understands what the equation represents, which is mass-energy equivalence, and what the value of the constant c is, one can see how much energy is equivalent to a small amount of mass. As noted, it is meaningless without the context, which is that E and m have been defined, and have then been theorized to be two versions of the same thing, and c has been measured. Robert McClenon (talk) 16:10, 18 September 2015 (UTC)

Mass–energy_equivalence#Others notes some antecedents for Einstein's most famous equation, and Einstein was heavily influenced by Henri Poincaré. Einstein's contribution is not to be minimized, but it is important to explicitly note that he did not invent the concept out of whole cloth; indeed no scientist works in isolation. As noted by Isaac Newton, (and many others before and since) "If I have seen farther, it is only by standing on the shoulders of giants. Einstein's work itself is revolutionary, but not because it was created and discovered solely by him. Science is syncretic by nature, taking the work of others and building upon it in novel ways. --Jayron32 16:17, 18 September 2015 (UTC)

You're right that technically E=Mc² is a meaningless string of math unless you put it into some kind of a context...not least by explaining what 'E', 'M' and 'c' stand for. If 'c' is the size of a square swimming pool, and 'M' is the depth of the pool, then 'E' is the volume of the pool. In that case, E=Mc² is a true equation without any relevance to relativity. On the other hand if 'E' is the charge on the electron, 'M' is the mass of the Earth, and 'c' is the number of articles added to Wikipedia today - then the equation is incorrect gibberish.

The only reason you see scientists scribble an equation on a chalkboard and stand around to discuss it without further introduction is because they are probably from the same field of study - and probably adhere to the same conventions as to what the symbols mean.

If people from different fields meet under those circumstances, there may be a considerable period of pointing at bits of the equation and saying "What does that stand for?". A classic example of that is that Mathematicians use the letter 'i' to indicate a complex number - where people who do electrical calculations use 'j' for the exact same thing. There really aren't enough letters in the latin/greek/whatever alphabets/fonts to do things completely uniquely - so there's always room for misunderstanding...sometimes even within the same field.

SteveBaker (talk) 19:45, 18 September 2015 (UTC)

if 'E' is the charge on the electron, 'M' is the mass of the Earth, and 'c' is the number of articles added to Wikipedia today - then the equation is incorrect gibberish. Depends what units of measurement you use:) DMacks (talk) 19:55, 18 September 2015 (UTC)

Actually, even if you know that 'E' is energy and 'M' is mass and 'c' is the speed of light, the equation doesn't tell you much. You also need to know that 'E' is the amount of energy you get if you convert the mass into energy. If you didn't know that mass and energy could be converted (or indeed are the exact same thing) - then the equation might still be meaningless - or at least easily miscontrued. Maybe 'E' is the amount of energy it takes to get an object of mass 'M' to accelerate to the speed of light - or the amount of energy it takes to cause the mass to turn into a black hole? It's not any of those things - but if you hadn't read what Einstein had to say about mass, energy and relativity - then those are plausible interpretations of the equation. SteveBaker (talk) 19:53, 18 September 2015 (UTC)

Further to the original poster's point, Einstein himself didn't originally write it as "E = mc²". What he wrote in 1905 was that the mass changes by L/V². --174.88.134.156 (talk) 05:12, 19 September 2015 (UTC)

It makes as much sense a E = 1/2 m v^2. Units are the same. I find it fascinating that the 1/2 disappears but it's the same level of understanding of conversions to energy. --DHeyward (talk) 19:37, 19 September 2015 (UTC)

Closest animal to humans with more than 2 nipples?

What is the closest animal to humans where the animal has more than two nipples? The Great apes have only two, and all pictures that I can find of other primates do as well. Naraht (talk) 20:48, 18 September 2015 (UTC)

See Mammary_gland#General, which has a nice table of nipple numbers (and ranges!) for some mammals. Tantalizingly, it says "The number of nipples varies from 2 (in most primates) to 18 (in pigs)."- which sort of hints that there might be a primate with median number of nipples > 2, though the sentence cites no sources. Anyway, I thought maybe some of the Strepsirrhini might have more than two nipples... and with a bit of scrounging, this book [1] claims that female Greater_bamboo_lemur have four nipples - so that will be hard to beat as an answer to your question. If you think the source is reliable and want to thank me, you can mention this in the first linked article and add the book as a citation- then lots of people will be able to more easily learn this interesting fact :) SemanticMantis (talk) 21:16, 18 September 2015 (UTC)

My guess would be Mark Wahlberg :) - Nunh-huh 21:25, 18 September 2015 (UTC)

Right, the reason I spoke of median number of nipples is that supernumerary nipples are quite common in mammals in general and humans specifically - chances are, many people reading this have more than two nipples. SemanticMantis (talk) 21:27, 18 September 2015 (UTC)

Yes, the little ":)" was a smilie, not a depiction of a chest with the normal number of nipples. - Nunh-huh 21:56, 18 September 2015 (UTC)

Snookie. loupgarous 12:37, 20 September 2015 (UTC)

Poisoning from wood when smoking meat

Can any old wood from a forest in, say, Hainan be used to smoke meat, or could some horrible cyanide chemical come out and make the meat poisonous? Anna Frodesiak (talk) 21:25, 18 September 2015 (UTC)

Well... the dose makes the poison. Smoked meats contain benzo(a)pyrene, a known carcinogen. Smoked meats specifically may increase rates of cancer, depending on method and intake [2]. I don't know whether you want to consider that "poisonous" or not, but thought it was worth mentioning. SemanticMantis (talk) 21:36, 18 September 2015 (UTC)

Normally poinsonous is okay. I'm talking about something that will make me have to get rushed to the cemetery. Anna Frodesiak (talk) 21:42, 18 September 2015 (UTC)

There are always warnings about disposing poison ivy, poison oak, & poison sumac by burning, as this creates a hazard to those exposed to the smoke. Clearly not a good idea for barbequing. Similar caveats about other poison-containing plants like oleander would seem to apply.Nunh-huh 21:55, 18 September 2015 (UTC)

Cyanide will just combine to the surface of the meat and produce the smell of bitter almonds. So not cyanide any more. Frying certain mushroom can release fatal amounts of cyanide gas. Wood smoke is rich in Carbon Monoxide. Too much of that may ruin your whole day. Why are you asking? It might help us to answer your question. --Aspro (talk) 22:12, 18 September 2015 (UTC)

Antiaris Poison Arrow Tree 箭毒木 is found in Hainan. This sounds bad. But if you believe the writings, it is so toxic that you would probably die before cutting the tree down. Graeme Bartlett (talk) 22:18, 18 September 2015 (UTC)

The dust from some hardwoods produced by woodworking machinery can be toxic and even carcinogenic - see under the heading "Hazards" here. I wouldn't want to use those for smoking meat. If you look at this list there are dozens that can cause problems. Smoked meat in general has also been found to be a problem and to quote from this paper (the one mentioned above) "As observed during the last 10 years in a certain district of Hungary with a Slovenian population, the percentage of stomach cancer among all types of cancer is nearly twice as high (47-50%) as in Hungary altogether (29.9%). In this special district, predominantly home-smoked meat products are consumed". Richerman (talk) 22:26, 18 September 2015 (UTC)

Dust is a special case, and dust of substances normally considered safe and nontoxic, like cotton, can be both carcinogenic and explosive. The carcinogenic effect is due to dust particles irritating the lungs, etc, leading to inflammation, then cancer. The explosive effect is due to the increased effective surface area and hence rate of combustion. So, inhaling any dust or smoke should be avoided, where possible, but once the smoke is absorbed into the meat, it should no longer be toxic, for this reason. If the original wood was toxic, though, then that form of toxicity may be transferred to the meat. StuRat (talk) 02:18, 19 September 2015 (UTC)

I'm asking because I was thinking of making a smoker. I wasn't sure what wood to use. All the trees are unknown to me. Anna Frodesiak (talk) 23:53, 18 September 2015 (UTC)

Thinking of making a smoker. Good for you. There is nothing like home cured meat. Silly answer I know, but have you asked, friends & neighbors? Do you have a local government office or town hall. They will have Food and Hygiene departments. They will probably know the local preferred wood. Local food retailers will probably be able to tell you what wood was used in curing the meat that they sell. Some people will sell wood chippings for smoking (look in local paper) at exorbitantly high prices but often one can get the same wood for free. How are you going to build the smoker? If a local person has given you the plans or designs, he may be able to give advice. Also, don't forget your local library (for the young readers here – libraries are what we depended upon before the internet). Liberians are extremely skilled at answering quires. As custodians of knowledge they are like Wikipedians here on the help desk -but just a lot smarter. Also, smoking alone may not be enough. It may need salting and saltpeter. Another reason to go to the library to discover the best way of preserving what ever meat you're going to smoke. --Aspro (talk) 00:40, 19 September 2015 (UTC)

Librarians can even point you to a dictionary to look up the spelling of a word. :-) StuRat (talk) 02:08, 19 September 2015 (UTC)

Why ? When eye can use my spooling chequer which came instilled with my pea sea.--Aspro (talk) 02:37, 19 September 2015 (UTC)

Friends have never tried it. Neighbours, locals, countryside folk, and local retailers (bless their hearts) will give guesses and bizarre, confusing, and inaccurate answers if any at all. Facts and information are not so important here. Money is what everyone is thinking about. :) So, nice folks, but not reliable sources. :) The govt and local library will have zero information on this too. I'm afraid to buy wood because they treat wood with chemicals here and who knows where they got it. I want to build the smoker like a little canvass tee-pee. I'm not sure if I should get saltpeter because I haven't researched that. I thought just smoke and salt should do the trick. Anna Frodesiak (talk) 02:06, 19 September 2015 (UTC)

Leaving aside the question of toxicity, most woods just won't give the meat a good flavor, so should be avoided for that reason. StuRat (talk) 02:10, 19 September 2015 (UTC)

Oh dear. I didn't think of that. Anna Frodesiak (talk) 02:26, 19 September 2015 (UTC)

Where on planet Earth are you situated? Tell us that and a little googling might throw up the local woods that are used for smoking. Also, have you actually inquired at local library and confirmed that they have zero information on this? If you live some where like the US were the Gov. spending on libraries is so miserly that librarians are just book-store-minders, that would be understandable. But if you live anywhere in the rest of the English speaking world - a librarian is worth every dollar he/she gets paid. Run this question past one.--Aspro (talk) 02:56, 19 September 2015 (UTC)

I really appreciate what you are saying. Really. The thing is that I live in Haikou, Hainan, (China). Things are a little less organized here. Honestly, the library will have nothing on smoking or what local woods to use. There's just no way. Also, Google is blocked here.

@Anna Frodesiak: FYI, Smaller-sized commercial smokers exist that run on pre-made wood chip patties that are loaded into them. While not as authentic as "smoking from scratch", they are functional to various degrees. Thing is, though, you have to keep ordering more chip patties when they run out. North America¹⁰⁰⁰ 06:23, 19 September 2015 (UTC)

There are a bunch of internet sites for home-smoker enthusiasts, with forums for discussing construction, recipes, etc. First one I found was http://www.smokingmeatforums.com/ for example. I know, the plural of "I read it on some chatsite" isn't "reliable source", but they surely would have some comments on what woods are good. DMacks (talk) 10:10, 19 September 2015 (UTC)

Here is one that lists many woods. All About Smoke Woods--Aspro (talk) 22:32, 19 September 2015 (UTC)

One warning I've heard fairly often is to avoid soft woods such as pine, fir, and spruce. The pitch is not good. Alton Brown has suggested avoiding commercial suppliers of sawdust (for example, furniture shops) for that very reason - unless you can be sure that there is no softwood mixed in. However, in general, he does suggest using sawdust rather than sticks or branches because they burn in a more controlled way. 99.235.223.170 (talk) 21:51, 19 September 2015 (UTC)

Thank you all for your very thoughtful and informative comments. As for the original question about some toxin coming out and making the meat poisonous, I will take that as a no, almost certainly not. Cheers to all. Happy smoking, hearty eating, and normal blood pressure forever. :) Anna Frodesiak (talk) 00:02, 20 September 2015 (UTC)

Resinous woods such as pine, spruce and other members of the conifer family aren't a good choice to cook over, the terpenes in their sap tastes horrible and may be toxic (it wouldn't be much different than marinating your food in turpentine). Even worse is oleander and its relatives like the desert rose, which have cardiac glycosides and other toxins in their sap that exert a digitalis-like effect on the human heart; hunters have died from eating meat cooked over the oleander. The foxglove shrub shouldn't be used to cook over, either, for it contains the potent digitoxin, which can cause drooling, abnormal heart rate, cardiac arrhythmias, weakness, collapse, dilated pupils, tremors, seizures, and even death.

Finally, PLEASE don't cook over lumber - it can difficult to tell when a plank or sheet of plywood's been treated against insects or mildew, and the chemicals used to treat wood are ALL toxic to people, sometimes fatally so ("pressure treated" lumber is placed in huge autoclaves where very poisonous arsenic, borate or copper salt solutions are pumped into the wood at high temperature and pressure). loupgarous 13:05, 20 September 2015 (UTC)

Thank you, loupgarous Okay, so to be clear: I should smoke food only using pressure-treated plywood of alternating layers of oleander and pressed foxglove shrub, glued together with plutonium/cobalt 60 based adhesive. Kidding. Actually, this last post is the one I'm most grateful for. I will definitely not be smoking anything, period. I just have no clue what wood is what. Ah, that gives me an idea. I can easily identify wild Lychee trees. They are everywhere. Is that safe? If so, Bob's your uncle, and I'll smoke away. :) Anna Frodesiak (talk) 13:23, 20 September 2015 (UTC)

Hi Anna Frodesiak, a few wood types I can definitely

recommend based on my own and family experience are fruit woods such as grape, apple or pear, my brother smokes meat commercially using pear. Hickory and oak are also good but have a much stronger aroma than the fruit woods. Roger (Dodger67) (talk) 22:59, 20 September 2015 (UTC)

Hi Roger (Dodger67). I'd love to get those woods. But here, I'd just go get the wood out of the jungle or forest and I don't know what tree is what, except for coconut, lychee, ficus, and I think that's about it. Anna Frodesiak (talk) 23:44, 20 September 2015 (UTC)

Now that we know what your likely wood choices are, please read our article on the Lychee - it turns out that consumption and/or exposure to some phytochemicals in the lychee shrub's associated with a form of encephalopathy seen only in places like India and northern Vietnam when young and old local residents turn out to harvest the lychee fruit. It wasn't until recently that phytochemicals in the lychee were discovered to cause or at least help this syndrome along. The ficus - that really depends. I'm assuming from your concern with lychee wood that you're talking about the ficus rubber tree, which has an irritating sap. I'd leave that alone, too - not very toxic, but might give you and your dinner guests a case of the "green apple two-step" (diarrhea/upset stomach). Where I'm from (the American South) we love our fig fruit, and no one'd be crazy enough to chop a fig down to smoke meat over, so I have no idea how it is to cook over. As far as coconut wood, that depends on what your soil's like. In many places in India, arsenic's a concern in ground water, and it bioaccumulates in many woods. Like coconut wood. Local universities might be your best resource.

Glad to help, and I do hope you find a good smoking wood; my wife and I smoke fish that I don't ordinarily like with hickory, and it entirely changes the taste to something ambrosial. loupgarous 04:45, 21 September 2015 (UTC)

I would love it if there was hickory here.

Okay. So no lychee. Maybe I will try coconut husks. I see forums saying okay things about that. Anna Frodesiak (talk) 07:22, 21 September 2015 (UTC)

Why would an elephant do this?

Why would an elephant do this? What are some possible explanations? To me it just looked like the elephant didn't like those humans sitting there. I realize I am just asking for speculation. But maybe someone is familiar with elephant behavior or maybe someone has some insight into this based on some cues that I may be failing to notice. Bus stop (talk) 21:55, 18 September 2015 (UTC)

Some possible explanations and relevant info at territorial behavior and Elephant#Attacks. SemanticMantis (talk) 22:08, 18 September 2015 (UTC)

Some comments:

1) You should never get that close to a wild elephant, or any wild animal that can kill or seriously injure you. They should have walked away as soon as the elephant approached.

2) Staring at it might have been seen as a challenge.

3) "Teenage" elephants exhibit the same recklessness as human teens. If that was an adolescent male elephant, they are far more dangerous.

4) See rogue elephant. (The fact that there's a term for it shows that it's not all that rare.) StuRat (talk) 02:28, 19 September 2015 (UTC)

Note that the description says poor eyesight may have been a contributing factor. Also the description says they were advised to stay very still which would be difficult if they were walking away. Nil Einne (talk) 14:59, 19 September 2015 (UTC)

You would start walking away when the elephant first approached, not wait until it was that close, then try to walk away. StuRat (talk) 15:13, 19 September 2015 (UTC)

Who said anything about waiting until it was close? It's not clear from the video when the elephant first became visible, there's apparently a slope and also some sort of wooden balcony which may have obscured the elephant. It's not really clear if there really was somewhere they could have gone which would be safe from the elephant, how many elephants, there were etc. All that's really mentioned it the elephant was eating a pod, and when it approached they were advised to stay still. Unless you're saying they should have started continously walking away when the elephant was 500m+ away which we don't know was realisticly possible, there's a fair chance the elephant could have easily charged them down if it wanted to, like if they startled it by all walking away. Nil Einne (talk) 15:54, 20 September 2015 (UTC)

Sure it could outrun them, but it's not a predator, after all. It has no interest in hunting people. But if it finds itself close to people it may feel threatened and attack. If they are far away, it won't worry about them. In this case it seems it may have come close for the food, then only spotted the people at the last minute, perhaps due to poor eyesight and the people staying still, and then it panicked. Think about how you might react to a spider you spot in the woods. If it's far away, you would probably avoid it, but if a spider is all of a sudden in your face, you might try to kill it or at least push it away. And, just like the elephant, it might be in your face because you walked into it's web. StuRat (talk) 03:58, 21 September 2015 (UTC)

This provides the same perspective but it repeats, I think allowing better analysis. Bus stop (talk) 23:15, 20 September 2015 (UTC)

Metaquestion: Why did my question receive no answers?

Original question was posted on the maths desk with a note on the science desk asking for contributions at the maths desk. I am now asking why the question did not attract any answers. Please see the metaquestion at [3], and leave answers there. Thank you! --NorwegianBlue ^talk 22:49, 18 September 2015 (UTC)

It could be because this is a very specializes form of satistics. It may be more productive to post it some where like [4] or [5]. Most of us here would not know a ROC curve, even if one hit us on the back of the head.--Aspro (talk) 23:32, 18 September 2015 (UTC)

• Well, sure, if it knocks you out from behind ... —Tamfang (talk) 07:09, 19 September 2015 (UTC)