Wikipedia:Reference desk/Archives/Science/2008 May 13

= May 13 =

Can my macaw breed with his macaw?
Mine: Female hyacinth macaw

My friend's: Male red and green macaw

Supposing that the two birds get along and eventually pair up, will they be able to breed? --81.77.245.65 (talk) 00:21, 13 May 2008 (UTC)


 * I'm no expert, but it should work. Hyacinths are reported to be very difficult to breed, though.  Considering that our page lists hyacinth macaws as endangered, wouldn't you rather want to see if a zoo or |another breeder in the area has a male hyacinth and breed yours with that one? Just a suggestion. -71.236.23.111 (talk) 01:44, 13 May 2008 (UTC)


 * I don't think so. They aren't even in the same genus.  bibliomaniac 1  5  04:22, 13 May 2008 (UTC)


 * Bird hybrid has a couple of examples. Somewhere it said that different genera don't breed in nature, but some mate successfully in captivity. It would just be a pity in this case because the species needs the contribution of every surviving member for genetic diversity.  Hope you'll decide to get a suitable hyacinth gentleman for her. Lisa4edit (talk) 05:37, 13 May 2008 (UTC)


 * From what I've read on the internet, any large macaw can breed with any other large macaw and produce fertile hybrid offspring. As I understand it, it can be quite a common occurrence if you have an aviary containing several different species. The other day, I saw a picture of a third-generation 'mutt' hybrid which was (apparently) descended from four different species. I've seen a few photos of Hyacinth x Ara macaw hybrids too - they do look rather odd and (IMO) quite ugly. Imagine a Hyacinth Macaw-sized/shaped head and bill on a much smaller and thinner body, with random bald patches scattered around the face.


 * As others have alluded to, it's probably best to find another Hyacinth if you're planning on mating her. Intentionally breeding hybrids of endangered species is something that is somewhat frowned upon amongst macaw enthusiasts. --Kurt Shaped Box (talk) 14:27, 13 May 2008 (UTC)


 * Why are they considered separate species, then? Isn't being able to produce viable offspring together the definition of being the same species? There might be some blurred lines between species within a genus, but I would have thought species from different genera would be more distinct. --Tango (talk) 22:14, 13 May 2008 (UTC)


 * Not "viable", "fertile". But there are other factors.  Tigers and lions breed in captivity. In nature they have different ranges, so they don't meet.  Birds also seem to be a bit more flexible reproduction wise than taxonomists gave them credit for. Some of their hybrids are fertile and do reproduce. --Lisa4edit (talk) 05:20, 14 May 2008 (UTC)


 * What's the technical definition of "viable", then? --Tango (talk) 14:38, 14 May 2008 (UTC)


 * The dictionary says this for fertile they use the "reproduce" meaning []. Have some mercy on the taxonomists. What are they going to do? They spent all this time sorting things into a system splitting the finest of hairs and then those animals just go ahead and mate in some cage and throw everything off kilter :-) 71.236.23.111 (talk) 17:05, 14 May 2008 (UTC)


 * Go easy on the hybrid macaws too. No-one ever told them that it was scientifically-impossible for them to reproduce. :) --Kurt Shaped Box (talk) 22:32, 14 May 2008 (UTC)


 * Thanks for all the answers. I wasn't definitely going to attempt to breed her with my friend's macaw. Just sounding out the possibilities. I feel sorry for her when she starts going broody at about this time every year and I see her go through all that nest making behaviour for nothing. I've considered obtaining a male Hyacinth for her but they seem to be very expensive these days. Since when did that happen? My bird was only slightly more expensive than a large 'Ara' macaw when I got her in the early 80s. --90.242.185.237 (talk) 21:51, 15 May 2008 (UTC)


 * If your hyacinth macaw gets suffientily lonely, she may even try to breed with a water hyacinth, but I would think the probabilty of this mating producing any offspring would be rather low. :-) StuRat (talk) 12:26, 16 May 2008 (UTC)
 * Don't know when they became rare. Depending on where you are there's likely to be a "parrot society" or some such in the area where you might find someone with a male.  If you happen to be in the U.K. the London Zoo has a breeding program.  Contacting any such sources is likely to come you a lot cheaper than buying another bird.  Since you've found out what they cost, I guess you can do the math of what a successful mating might result in.  Someone with a male might be very willing to split the spoils.  Don't plan on celebrating yet.  There are many reports that say they are hard to breed successfully. Lisa4edit (talk) 05:24, 18 May 2008 (UTC)

Animal stripes
Do baby tigers, leopards, and zebras get more stripes or spots as they grow older, or do the stripes and spots they are born with get bigger? Mr Beans Backside (talk) 19:07, 12 May 2008 (UTC)


 * Don't know about either leopards or tigers, but ozelots and domestic cats are born with a fuzzy version of their general fur pattern that gets more defined with age. Some changes happen, but mostly in the "belly" area (what you see when the cat lies on its back]. Lion cubs are born with spots that disappear as they mature.  OR one of our domestic cats had white tufts behind her ears, that disappeared as she matured.  Some cats that appear black (Melanism) at birth can later grow stripes or spots. Hope this helps. --71.236.23.111 (talk) 20:16, 13 May 2008 (UTC) For further reading Gene expression and Cat coat genetics could get you started.Lisa4edit (talk) 21:04, 13 May 2008 (UTC)


 * With dogs the spots definitely get bigger - not more numerous. We have photos of our dog (a Border Collie/something mix) when he was 1 month old and about 6" long. The spot pattern is IDENTICAL to photos we have of him at 10 years old and four feet long.  It's true in humans too!  My son was born with a dark birthmark and a patch of starkly white skin (both on his stomach) - both have grown bigger with him to age 17 (although they've both faded towards more normal skin color to the point where you can hardly notice them). 66.137.234.217 (talk) 14:24, 17 May 2008 (UTC)

Push/press ups with equipment
Following the ergonomic question above, I was wondering why people recommend using equipment for pushups, say holding small dumbells to the floor. Does this technique work different muscle sets or is it a ploy to sell more equipment? Julia Rossi (talk) 02:13, 13 May 2008 (UTC)
 * Personally, hands flat on the floor stresses the wrists more than using little things with handles which allow the hands to be more curved. Edison (talk) 04:27, 13 May 2008 (UTC)
 * Thanks Edison. Julia Rossi (talk) 09:58, 13 May 2008 (UTC)
 * Now things have changed since we thought that knuckle press-ups were "better" because they hurt more! -- Q Chris (talk) 07:09, 14 May 2008 (UTC)
 * Pushups using dumbells or similar are better because you can get a deeper pushup, resulting in more muscles working harder. Luxosus (talk) 14:05, 14 May 2008 (UTC)

help in cleaning up a dog's skull
Hi what steps should I take to clean up a skull that I found. here are the specifics:
 * 1) Found half-buried in sand used for construction (the greyish one)
 * 2) Most of the skull is dark brown in color. An unburied part is cracked and whitish.
 * 3) The lower jaw is missing.
 * 4) My female co-worker was disgusted when I picked it up and kept it.
 * 5) It looks like a dog's skull, about 15-20 cm long.
 * 6) It still has teeth.
 * 7) It smells funky but I can't find any flesh clinging to it. No idea regarding the brain though

I want to make it sparkling white and tough to boot. I hope the ingridients that you would reccomend are easily found and cheap.-- Lenticel ( talk ) 06:03, 13 May 2008 (UTC)


 * For a similar question in March 08 and preserving a rabbit's skeleton in Feb 08 here with one of the answers as ants ants ants. On a documentary I saw a forensic scientist using detergent with its enzymes or whatever, breaking down pig's parts, but don't remember that it mentioned skeletons, only ways of getting rid of bodily crime evidence.   Julia Rossi (talk) 06:16, 13 May 2008 (UTC)


 * You should win a prize for hitting on a topic for an article missing from wikipedia. Our articles mention "preparation" and "preparator", but there's no page.  Taxidermy doesn't cover it. Pathologists' Assistant I thought was a very odd link from the German wikipedia, which does have and article. --Lisa4edit (talk) 06:24, 13 May 2008 (UTC)


 * Then there's google cleaning your own animal bones by soaking in water with some detergent and more – like how to clean a skull (taking care not to overdo things) here. This article has really clean white skulls. All common ingredients and cheap as so good luck, Julia Rossi (talk) 06:33, 13 May 2008 (UTC)
 * I like the last two sources. I'll have a sparkling skull in no time. Thanks!-- Lenticel ( talk ) 07:05, 13 May 2008 (UTC)

hydrocarbons
what is the formula for finding how many isomers a hydrocarbon has? —Preceding unsigned comment added by 41.204.224.23 (talk) 10:20, 13 May 2008 (UTC)
 * Homework alert. Read the notice at the top of the page, we will not do your homework for you. Regards, CycloneNimrod Talk? 12:09, 13 May 2008 (UTC)
 * On the contrary, I think it's unlikely to be a homework question (if so, it's a trick question, because there is no formula you can just write down). For questions like this the On-Line Encyclopedia of Integer Sequences is an invaluable resource. The sequences you're looking for are and . —Keenan Pepper 19:33, 13 May 2008 (UTC)

Current in capacitor and nature of magnetic fields
I have a difficulty understanding how current passes between an insulator in capacitors. Also what exactly is the nature of magnetic fields? What passes in flux lines? Is it a particle, a massless thing with momentum? Or something else entirely? Bastard Soap (talk) 10:48, 13 May 2008 (UTC)


 * Current doesn't really pass across the insulator of a capacitor. What happens is that electrons accumulate on one plate of the capacitor and "holes" (the absence of electrons that would normally be there when the material is neutrally charged) accumulate on the other.  The resulting electric field results in a voltage difference between the plates.  (You could think of this as analogous to blowing up a balloon; the air you blow isn't really going anywhere, but is building up until the pressure exerted by the atmosphere and the strain of the rubber equals the pressure at the mouth of the balloon, or until the balloon pops of course.)  The amount of charge it takes to produce a given voltage difference is defined as the capacitance of the device:
 * $$C = \frac{q}{v}$$
 * If you connect a DC voltage source (e.g. a battery) directly to the terminals of a capacitor, current will flow and charge will build up until the voltage across the capacitor equals that of the voltage source, and then no current will flow. That is why capacitors are treated as an open during DC analysis of an electronic circuit.  --Prestidigitator (talk) 16:44, 13 May 2008 (UTC)

But in practice it is not correct before the capacitor charges up right? Bastard Soap (talk) 16:58, 13 May 2008 (UTC)


 * If you mean the treatment of the capacitor as open, yes, it's not correct until then. I don't think the reason current "passes through" a capacitor is much different from the reason it passes through a conductor. The electromagnetic repulsion between the charge carriers can get through the insulator; it's only the charge carriers themselves that can't. If you force charges to accumulate on one side of a capacitor, they repel the charges on the other side, leading to a current there. The only difference is that, since the charges have nowhere to go, there's a limit to how far you can push them before you reach the voltage limit of your battery (or whatever) and no more current flows. In the case of AC there's no net motion of the charges and so no net buildup, and the capacitor is not much different from a segment of wire. As for the nature of magnetic fields, I'll leave that for someone else to answer. -- BenRG (talk) 18:01, 13 May 2008 (UTC)


 * I see capacitors as very different from mere wires for AC. The "non-wire" nature of capacitors in AC circuits is useful in oscillators, filters, motor-starting, power factor correction,  and phase shifting circuits. Edison (talk) 03:32, 14 May 2008 (UTC)

So nobody knows what the damn flux is? It keeps it's cards close to it's chest Bastard Soap (talk) 16:38, 18 May 2008 (UTC)

Darwin
Was Charles Darwin a eugenicist or a social Darwinist? --Begantrue (talk) 22:01, 13 May 2008 (UTC)
 * Neither, as far as I know. They're not really opposites, either, so I'm not sure I understand your question... You would probably be better off on the humanities reference desk - this isn't really a science question. --Tango (talk) 22:11, 13 May 2008 (UTC)


 * Neither. He was a naturalist. Also, what's this troll smell? &mdash; Kieff | Talk 23:12, 13 May 2008 (UTC)
 * It's a legitimate question, one historians have been asking for some time now. It's a question about what beliefs he held and wrote about, not his occupation. He did write on both topics. --Captain Ref Desk (talk) 02:48, 14 May 2008 (UTC)


 * For a fairly complete approach, by a respected historian of heredity, you might look up this article: Diane B. Paul, "Darwin, social Darwinism and eugenics", in Jonathan Hodge and Gregory Radick, eds. the Cambridge Companion to Darwin (Cambridge University Press, 2003), 214–239.
 * In short: Darwin was on the fence in both cases. He valued his cousin Francis Galton's work primarily because Galton established, as far as Darwin was concerned, that intelligence was as inheritable as stature and skin color. He believed that it was possible, as Galton claimed, that society could be breeding itself into inferiority, but he was not at all sure that society could or should do anything about that. He considered Galton's view of a state that could help regulate breeding as "utopian". Neither he nor Galton believed at all in anything that looked or sounded like even the coercive form of eugenics practiced in the United States, much less under National Socialism.
 * Darwin's intellectual priority was convincing people that evolution was plausible. He did this by looking for things in animals that he saw in man, as a way of bridging the gap. He was not interested in how human societies should organize themselves, not like Galton and Spencer were.
 * That being said, he didn't totally disown these ideas either. But eugenics was brand new and not totally formulated; social Darwinism was not yet a coherent set of principles (and certainly not under that name). Did he believe evolution applied to society? Yes, but he and everyone else just called it Darwinism at that point.
 * But in all things, the most salient aspect of Darwin is his fence-sitting. Read the sections on society in Descent of Man—he goes back and forth, is eugenics sensible, is it moral, does it make sense, over and over again, back and forth. (Origin of Species is written in much the same fashion, he circles around and around.) In the conclusion of that book he gets as close as he ever did to saying that perhaps the state should be keeping track of whether people marry their own cousins (he tried to get his friend Lubbock to pass a law that would mandate an investigation of this—and he himself always felt that his own children's sickly demeanors came from the fact that he had married his own cousin) and that people should give more attention to the heredity of their spouses than they usually did. But it is not very forceful, it is not the cry of what we would today consider a real eugenicist or social Darwinist. He did not denounce the ideas very strongly, but he did not support them very strongly either. They were not major forces on his agenda. --Captain Ref Desk (talk) 02:48, 14 May 2008 (UTC)

kitty's diet
If I give Fluffie nothing but meat and water, is that a guarantee that she'll get enough taurine? Is there any bird or mammal meat that's low in taurine? —Tamfang (talk) 22:09, 13 May 2008 (UTC)
 * Unfortunately it isn't that simple. I'm no expert in this area but a google search turns up many exceptions to the general rule that meat=taurine.  There are so many exceptions that I can only suggest that you speak with your vetinarian concerning your pet's diet.  BTW, the general rule is that mammal meat and fish are good sources of taurine.  Poultry is not included in that rule.  In fact, This Yahoo answer states that poultry is low in taurine.  This paper says ruminants are a poor source of taurine.  This page supports the previous two, indicating that chicken and beef are low in taurine.  (Subscription required) states that raw rabbit diets are low in taurine.  The list of exceptions keeps getting longer the more links I check.  The best bet is to ask your veterinarian.  152.16.59.190 (talk) 06:41, 14 May 2008 (UTC)
 * Apart from really asking your vet. You should at least put out a pot of grass for your cat. Although cats are carnivores, that doesn't mean they only eat meat in the sense of carcass that we consider such. A catch like a mouse or a bird contains plant matter and cats also eat insects if they get to go outside. That gives them a lot more variation in their diet than "meat only".Lisa4edit (talk) 07:29, 14 May 2008 (UTC)

Thanks all! —Tamfang (talk) 16:04, 14 May 2008 (UTC)

Thailand food production
What is one way that a country can increase the amount of food they can create without hurting the environment, while increasing their economy, making a valuable asset to their people, and making it a productive and sustainable part of their agriculture for future generations? Aka- Im doing a project on Thailand and I have to find An alternative or more efficient method of food production that would be benificial, economically sound, & environmentally sustainable for Thailand. —Preceding unsigned comment added by Sleppytime (talk • contribs) 23:57, 13 May 2008 (UTC)
 * Not hurting the environment is a difficult one, since pretty much everything carries a risk of some damage. Ignoring that requirement, there are all kinds of options: selectively bred varieties of crops, genetically modified crops, new pesticides, new fertilisers, new agricultural tools (better tractors, ploughs, harvesters, etc), introduction of new insects to fertilise crops, the list goes on. Of course, Thailand already has quite advanced agriculture, as far as I know. There's always room for improvement, but I doubt there are any obvious things that would have a major impact, since they would have done them already if there were. --Tango (talk) 21:05, 14 May 2008 (UTC)
 * There is no way to create more rice without changing the environment. Rice, like all plants, animals, fungi, bacteria, and otherwise, will naturally increase and decrease in population, and drastically is very common. Environmental change will naturally happen. Mac Davis (talk) 17:23, 15 May 2008 (UTC)