Wikipedia:Reference desk/Archives/Science/2014 April 25

= April 25 =

Nonhuman vocal flexibility (or, what does the fox NOT say?)
According to these sources, foxes produce an extraordinarily wide variety of calls, and can imitate the calls of a wide variety of prey species. Maybe it's no coincidence that humans also have this ability, and that humans and foxes are among the least-endangered species of apex predator? Have studies tested whether the diversity of sounds a species can articulate is correlated with its position on the food chain or its modern conservation status? Neon Merlin  03:50, 25 April 2014 (UTC)


 * There are counter examples of great vocalists who are extinct as well. Shadowjams (talk) 04:05, 25 April 2014 (UTC)


 * Mimicry can be an important survival skill, but sound mimicry is only one type, and there are many other survival skills besides mimicry. StuRat (talk) 12:52, 25 April 2014 (UTC)


 * When you consider the survival of foxes in an increasingly hostile world, there are many aspects to their lifestyle that make them well suited - for example, they are omnivores - this allows them to easily switch food sources be highly adaptable to environmental changes.  They also have a reputation for high intelligence.   Mostly though, their ability to survive in places where humans dominate means that they are less inclined to suffer when we encroach on their territory.  So why would you imagine that (of all things) vocal range has anything to do with it?   There are many more things that are by far more likely to be the dominant reason for their continued success.  SteveBaker (talk) 13:33, 25 April 2014 (UTC)


 * Agreed, vocalization is not likely to be a big factor. Usually, Animal_communication is more inflected and complex in social species, e.g. cetaceans, birds, simians, canids, etc. I just searched google scholar for any article that seemed to mention complexity of vocalization and trophic status, to no avail...
 * By far, most endangered species have that status because of humans mucking up the animals native habitats. Foxes, racoons, sparrows, rats, groundhogs, deer... these are all simply animals that deal well with habitat fragmentation and habitat destruction by humans. Sometimes called human commensal species, they have readily adapted to the environments that humans have created. Things like rats and sparrows reach far higher populations in human cities than in their historical wild ranges. Interestingly, both foxes and beavers were recently much scarcer, but are on the rebound throughout much of the USA, indicating to me (WP:OR) that it took a little time for them to sort out how to live in our world. SemanticMantis (talk) 15:25, 25 April 2014 (UTC)


 * Agreed. Foxes are renowned for their intelligence, as in Aesop's fables.  I saw one fox actually using cars to feed itself.  It waited off the shoulder of a road for a car to drive by, which seemed to scare rodents in the brush, who then moved, and the fox pounced on them when he spotted the weeds moving.  Also, I've never seen a fox dead on the road, so they apparently are smart enough and fast enough to avoid that fate, while cats seemingly are not.  StuRat (talk) 16:02, 25 April 2014 (UTC)


 * I saw a dead fox on the road near Hammonton, New Jersey in the summer of 2012. I think they are simply rare in comparison to house cats, which I will admit are not as clever. μηδείς (talk) 17:48, 26 April 2014 (UTC)


 * Here in south London, it's not at all unusual to see dead foxes on the road.--rossb (talk) 20:20, 26 April 2014 (UTC)


 * How long has that been the case? Have they had time to adapt to traffic? Neon  Merlin  01:14, 29 April 2014 (UTC)

The question of rules and mains of conductoring inserting
Why on the page about electric conductor is not been contain about the all ways of including a conductors in a electric which always been setting up the all electrical rules? I seen, that a parallel or a simple insertings of all conductors in a electric is been most interested than a material structure of all conductors. More thanks!--Alex Sazonov (talk) 10:36, 25 April 2014 (UTC)


 * Are you asking about a series and parallel circuits ? Our electrical conductor article is about a conductor itself, not how it behaves in an electrical circuit. StuRat (talk) 12:46, 25 April 2014 (UTC)


 * Yes, I’m about of a series and a parallel including in a electric. But it seems that all conductors always none before had been belong a way of a electrical including, because all conductors always been created by a ways of a electrical including, thats it seems that it must been in page about a electrical conductors. Thanks!--Alex Sazonov (talk) 14:36, 25 April 2014 (UTC)


 * You're welcome. In English, at least, an "electrical conductor" has a wider meaning than just a device in an electric circuit.  For example, saltwater is an electrical conductor.  So, we have a separate article about electrical circuits. StuRat (talk) 14:51, 25 April 2014 (UTC)


 * Thanks more at all, it been all conductors always are beening as ways of a electrical including, but of course you right in English it had been meaning as a material or as a structure of material which had a electro-statically magnetism as it been done.--Alex Sazonov (talk) 15:13, 25 April 2014 (UTC)


 * As had been know as well, a ways of a electrical including of all conductors may been doing a super electrical resonance, that’s why a way of a electrical including of a conductors will be done a superconductivity as I know well the science it. Thanks.--Alex Sazonov (talk) 17:07, 25 April 2014 (UTC)


 * We have an article on superconductivity, too. StuRat (talk) 18:00, 25 April 2014 (UTC)


 * Very thanks, it seems me that must be explain in page about a superconductivity thats, the fact of a superconductivity always is been a science electro-technical effect in a applied physics which effect, always has been a simple science base of all electronics and all microelectronics as why that a superconductivity was been scientifically discovered at first in a electro-technical engineering, and someone alls could be explain that a superconductivity always is been effect of colder of all metals, but someone science always wanted a science as a superconductivity always had been a science of very colder melting of all metals. It always seems me that a superconductivity always been good as electro-technical effect in a applied physics but not it been as a colder effect, lets I always think it is been always science.--Alex Sazonov (talk) 18:26, 25 April 2014 (UTC)


 * What seems strange to me is that resistance drops to zero at any temperature above absolute zero. If everything dropped to zero at the same time, that would make more sense to me.   StuRat (talk) 19:27, 25 April 2014 (UTC)


 * As I think, it always be a melting of metals, that’s a conductionary is been always lost!--Alex Sazonov (talk) 20:11, 25 April 2014 (UTC)


 * Is it, all metals always are doing another properties in a coldering?--Alex Sazonov (talk) 09:39, 26 April 2014 (UTC)


 * Are you asking if all metals have a critical temperature below which they are superconductors ? I'm not sure, so let me ask a new question at the bottom of the page. StuRat (talk) 12:39, 26 April 2014 (UTC)


 * It been, if all metals been doing another properties they always beening modify a static situation mode (effect) of it.--Alex Sazonov (talk) 17:09, 26 April 2014 (UTC)

Spider that looks (and kind of acts like) a fire ant?
Sitting on the porch I encountered what I thought was a fire ant - it looked exactly like one but with unusually large mandibles, and it's movements were certainly characteristic of one too. But when I went to relocate it, to my surprise it dropped down on a silky thread! So just out of curiosity, I decided to place it in a large fire ant hill on the edge of the property. In fact, it just meandered about on the hill for a while without so much as raising suspicion from the normally-aggressive residents. Any ideas what kind of spider it was? I didn't have a chance to get a photo, unfortunately. 70.117.71.28 (talk) 15:59, 25 April 2014 (UTC)
 * Things That Are Not Fire Ants may help :) --&mdash;  Rhododendrites talk  |  16:03, 25 April 2014 (UTC)


 * Cool find! I could be mistaken, but I didn't see any spiders on Rhodo's link. Ant_mimicry discusses that ant mimicry by spiders is very common, but is not very helpful for our purposes here. Also, many things other than spiders can make silk, and some of them are ants. E.g. weaver ants use silk to make nests. So, unless you clearly counted eight legs, and are sure there was no pedicel, you may have just found some other, silk-making ant.
 * With a little further searching, though mistaking this salticid for a fire ant seems totally reasonable, and they do often perform a classic rappelling escape maneuver, just as you describe. That youtube video suggests it might be a member of the genus Peckhamia, more pics on Bug Guide here . Also, salticids have a habit of waving their mandibles about, and that might also fit with your description. SemanticMantis (talk) 16:23, 25 April 2014 (UTC)
 * Gah! You're right. This is the link I should've copied, which linked me to the one above: morphology fail. Actually a spider in this one, though unidentified. It looks like there's also the Myrmarachne family of ant-mimicking spiders. --&mdash;  Rhododendrites talk  |  19:36, 25 April 2014 (UTC)
 * Cool, that link has a mantis ant mimic too! SemanticMantis (talk) 20:39, 25 April 2014 (UTC)

Slow neutrons
Why are slow neutrons better at inducing nuclear fission than fast neutrons? 65.92.5.76 (talk) 17:49, 25 April 2014 (UTC)


 * Per our neutron temperature article, which is the first search result Google returns for "slow neutron":
 * Thermal [i.e. "slow"] neutrons have a different and often much larger effective neutron absorption cross-section for a given nuclide than fast neutrons, and can therefore often be absorbed more easily by an atomic nucleus.
 * It happens that that cross-section is more relevant for readily-fissile materials; note elsewhere in the article, though, that fast neutrons serve their own purposes in fission-based applications (such as breeder reactors). &mdash; Lomn 18:00, 25 April 2014 (UTC)
 * May be a slowing neutrons are much of a inductionary and much of a magnetism that’s it is be faster?--Alex Sazonov (talk) 19:14, 25 April 2014 (UTC)

References to the cross-section are not an answer; that concept is just a way of expressing how likely the reaction is. It's like saying that the star Canopus is brighter than Alcor because its magnitude is a lower number, when the magnitude is just a way of expressing the brightness.

I suspect that there is no simple answer. --50.100.193.30 (talk) 23:00, 25 April 2014 (UTC)


 * There is an old but well cited paper on the subject that I shall not pretend to understand: . Someguy1221 (talk) 10:04, 27 April 2014 (UTC)

Bird with a red patch on the back of it's head ?
I saw this small bird in Detroit. It occurred to me that it could be a female cardinal, as females often have less color, but the pics I found didn't much look like it. Same for a female American robin, and they tend to be more orange than red, in any case. I did get a cell phone pic, but it's of such low resolution it may not be of much use here. StuRat (talk) 17:58, 25 April 2014 (UTC)


 * What color was the rest of the bird? Could it have been a Red-winged Blackbird? The red patch is on the wing, but maybe from an angle it could look like it was on behind the head. - EronTalk 18:05, 25 April 2014 (UTC)


 * Nope, I've seen those before, this patch was definitely on the back of it's head. The rest was rather drab, a mix of browns and grays. StuRat (talk) 19:17, 25 April 2014 (UTC)


 * Northern Flicker? Many woodpeckers have red bits on the back of their heads, but the flicker is the only one I can think of off-hand that's also brownish. --&mdash;  Rhododendrites talk  |  19:29, 25 April 2014 (UTC)


 * Could be it. We do have a woodpecker around here somewhere, I've heard the pecking.  This one was on the sidewalk look for bugs in the grass, though.  Do woodpeckers ever do that ?  It was also with another bird, that was black and looked like a crow.  Not sure if that means anything. StuRat (talk) 19:37, 25 April 2014 (UTC)


 * Flickers are sort of less specialized woodpeckers. I often see them around brush piles and weedy areas. From our article: "According to the Audubon guide, "flickers are the only woodpeckers that frequently feed on the ground", probing with their beak, also sometimes catching insects in flight." I would call flickers and robins more "medium", not "small." If it was actually small (e.g. sparrow-sized,) Jayron's suggestions below are also good. Also, most north american woodpeckers have some red on their heads. The smallest is the downy woodpecker (~large sparrow), medium is red-bellied woodpecker (~robin to jay sized, along with the flicker), and the largest, the pileated woodpecker. It is probably not the pileated, they are large, striking, and obviously a wood pecker. SemanticMantis (talk) 20:37, 25 April 2014 (UTC)


 * Everything except the size seems to fit with it being a Northern Flicker, and in particular the male Yellow-shafted Flicker. The article lists a length of 11-14 inches, which seems at least twice as long as my bird, but I'm not sure which Northern Flickers that applies to, and if male juveniles have the same appearance. StuRat (talk) 23:56, 25 April 2014 (UTC)


 * Maybe a Purple Finch or a House Finch? -- Jayron  32  20:26, 25 April 2014 (UTC)


 * If it's really a distinctive red patch, maybe a Ruby-Crowned Kinglet -- Jayron  32  20:31, 25 April 2014 (UTC)


 * Or a Ruby-crowned Kinglet. There's a big humbug over bird name capitalization at the MoS Talk, if you're interested. InedibleHulk (talk) 03:16, 26 April 2014 (UTC)


 * Yes, that could be it, too, and the size matches more closely with the bird I saw. The range map doesn't seem to include Detroit, although their summer range is north of Detroit and winter range is south of us, so I assume they fly past here in Spring, perhaps stopping for a rest and bite to eat (unless the crazy birds fly west to California then north from there, then back east).  Do range maps exclude their travel paths during migration ? StuRat (talk) 14:13, 26 April 2014 (UTC)

Note that possessive its has no apostrophe, although it is written above with one in error, by confusion with the common possessive ending -'s and the contraction it's used for it is and it has. Wikipedia provides a helpful table of the correct usages in English, German and French. 84.209.89.214 (talk) 22:09, 25 April 2014 (UTC)
 * (Come on now, play nice. This is completely irrelevant; we all make typos and this one isn't really any impediment to communication. Surely you have more helpful contributions to make?) SemanticMantis (talk) 22:45, 25 April 2014 (UTC)
 * The user Cuddlyable3 was banished from Wikipedia for making a nuisance of himself the same way the IP just did. The IP should restrain himself in future. ←Baseball Bugs What's up, Doc? carrots→ 23:36, 25 April 2014 (UTC)
 * The IP should also refrain from piping the verbs with the nouns. It's barbaric. Wikipedia provides many tables. As for the bird, I'm afraid my own contribution is also terrible. InedibleHulk (talk) 03:14, 26 April 2014 (UTC)
 * The term Typo includes errors due to mechanical failure or slips of the hand or finger, but excludes errors of ignorance, such as spelling errors. I don't see any typos here, do you? 84.209.89.214 (talk) 11:46, 26 April 2014 (UTC)

It will help if the hatting administrator explains why they claim this response to the OP's question is "off-topic". Should SB who has posted their opinion on the same subject earlier interfere with dialog now? JustAnotherUploader (talk) 23:48, 27 April 2014 (UTC)

Color-changing eyes
My sister's eyes change color. From birth until about 3 months old they changed between gray, green, blue and gold, like the girl's contact lenses here: http://4.bp.blogspot.com/-ctwEOwlzmYc/UGnUCTNnciI/AAAAAAAAAD4/WKZwNT_Ibe8/s1600/girl2.jpg By 4 months old she had hazel eyes and they stayed hazel until she was 12 years old. When she was 12 they turned light green for about one whole day and she didn't even notice until her friends started asking her about her contact lenses. But she wasn't wearing contacts! The next day her eyes were still green but you could see the hazel coming back. When she turned 14 her eyes started turning almost black during the winter and in the summer they turn light brown, not hazel but light brown. Now its spring and she has one light brown eye and one dark brown eye. This might sound crazy but its true. Her eye color changes were noticed not only by her but by her friends and family, sometimes even before she had noticed it herself! So what does this mean? She also wants to know if they'll ever change back to blue or green. — Preceding unsigned comment added by 68.8.106.52 (talk) 18:34, 25 April 2014 (UTC)


 * These links might be helpful.
 * http://www.allaboutvision.com/askdoc/
 * http://www.geteyesmart.org/eyesmart/ask/index.cfm
 * —Wavelength (talk) 18:50, 25 April 2014 (UTC)


 * An explanation is at http://www.allaboutvision.com/conditions/eye-color.htm.
 * —Wavelength (talk) 18:54, 25 April 2014 (UTC)


 * The article Heterochromia iridum should be of interest to you. While one would assume that a physician would look for some of the causes listed there in routine eye exams, it wouldn't be bad to make sure he gets a full patient history next time.  But hazel eyes are just plain complicated and tend to change in appearance with circumstance. Wnt (talk) 20:55, 25 April 2014 (UTC)

How does nuclear fusion generate energy?
It seems to me that a nuclear fusion reaction like deuterium + tritium --> helium + neutron should result in an energy loss rather than an energy gain. The nuclear binding energy in a nucleus should be approximately proportional to the number of pairs of nucleons. Well, deuterium has one pair of nucleons, tritium has three pairs, while helium has six. So it seems that there should be an increase in nuclear binding energy, rather than a decrease. 65.92.5.76 (talk) 19:11, 25 April 2014 (UTC)

EDIT: Ignore question, I just realized that binding potential is negative. 65.92.5.76 (talk) 19:23, 25 April 2014 (UTC)


 * Binding energy varies with nucleus size. Nimur (talk) 21:21, 25 April 2014 (UTC)

Please recognize a flying bug


It is about 1 inch long. Gil_mo (talk) 20:05, 25 April 2014 (UTC)
 * Where is it? (as in, what part of the world?)  -- Jayron  32  20:24, 25 April 2014 (UTC)
 * Middle East, Israel. Gil_mo (talk) 20:45, 25 April 2014 (UTC)


 * Very blurry photo. Possibly a mayfly, possibly of the family Ephemeridae, which can grow to 35 mm. If you feel like wading through the detailed entomology, here's a science article about mayflies of Israel, hosted on this site about all things Ephemeroptera . If you still have the specimen or have access to another, it should be fairly easy to confirm or deny membership to the Ephemeroptera order. Getting to family, let alone species, will be much more difficult. SemanticMantis (talk) 21:35, 25 April 2014 (UTC)


 * As far as I can tell it's a male Dorylus fulvus, also known as sausage fly. It's a male of an army ant. --Dr Dima (talk) 22:35, 25 April 2014 (UTC)
 * Good call! I was puzzled by the lack of "tails" for a mayfly, but (wrongly) ruled out hymenoptera due to lack of a visible "waist"/Petiole_(insect). SemanticMantis (talk) 22:42, 25 April 2014 (UTC)
 * Dr Dima, that looks pretty much like it. I'll try and get a better picture of another one and ask again, the photo is indeed blurry - the guy kept on moving. Thanks! Gil_mo (talk) 21:41, 26 April 2014 (UTC)