Wikipedia:Reference desk/Archives/Science/2020 January 11
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January 11
editQuark Magnetic Resonance
editCould an X ray laser, or someday a gamma ray laser, be applied to a bunch of protons, and although xrays are probably pretty weak and long wavelengthy compared to quarks size, gradually excite the quarks inside the protons until they emit a signal? I’m thinking of an immobile grid of hydrogen ions trapped on a sheet of insulating material, and pulses of xrays shot at them at some fraction of a resonant frequency.Rich (talk) 02:07, 11 January 2020 (UTC)
- This excited proton would be classified as a different particle, the
Δ+
. See Delta baryon for more info. Graeme Bartlett (talk) 07:14, 11 January 2020 (UTC) - If the idea is to get a signal from the quarks inside the proton, this can be done by high-energy collisions of other particles with the proton. You thought of using photons (which in a classical approximation are seen as "x-rays" of "gamma-rays"), but most convinently it is done with electrons or similar more massive particles. See Deep inelastic scattering. Dan Gluck (talk) 10:04, 11 January 2020 (UTC)
- What you are talikng about is called photo-excitation of baryonic renonances. There exist a lot of them. You can also read publications: for instance this. Ruslik_Zero 17:54, 11 January 2020 (UTC)
Why don't primates live in Europe and the Middle East?
editI know that humans are primates, and I know that there are a few apes on Gibraltar and in Saudi Arabia, but given that monkeys are so versatile and adaptable, why aren't there monkeys or apes living in European countries or across the Middle East? They live in hot, dry parts of Western India and in the Yemen, and they've adapted to live in cold parts of Japan, so why have they never come further north into Europe, etc. — Preceding unsigned comment added by 95.150.37.255 (talk) 17:47, 11 January 2020 (UTC)
- In Europe they were wiped out by Ace Ages. Ruslik_Zero 18:07, 11 January 2020 (UTC)
- There should have been more than enough time for nonhuman primates to move back into the rest of Europe and Asia since the ice ages. Thus, there must be some factor which keeps them from moving north. The obvious difference is the climate. While it gets somewhat cold in Japan, it certainly gets far colder in northern parts of Europe and Asia. The central regions of Europe and especially Asia, not having temperatures moderated by air coming off the ocean, can also suffer from extreme temperature variations. But there are certainly some regions of Europe, like southern Italy, where the climate would be acceptable to many primates. So, some other explanation is needed there, perhaps hunting from prehistoric humans or predation from animals such as dogs. NonmalignedNations (talk) 04:54, 12 January 2020 (UTC)
- If it's due to human predation, another question would be why monkeys haven't been hunted to extinction in Africa, as humans originated in Africa as well.
- Let's suppose the answer is that the tropical conditions in Africa just allow a higher density of monkeys while humans don't have as much of an advantage compared to cooler climates.
- Then the question is, why did monkeys survive in Japan? Is 40000 years (according to History of Japan) not enough for humans to have hunted them to extinction? Icek~enwiki (talk) 15:18, 12 January 2020 (UTC)
- "About 230 macaques live on the Rock of Gibraltar (=Europe). This population appears to be stable or increasing, while the North African population is declining". (article on Wikipedia). 93.126.116.89 (talk) 04:37, 12 January 2020 (UTC)
- Our article on Oreopithecus, an ape that lived in Italy 7 or 8 million years ago, says that "When a land bridge broke the isolation of the Tusco-Sardinian area 6.5 million years ago, large predators such as Machairodus and Metailurus were present among the new generation of European immigrants and Oreopithecus faced quick extinction together with other endemic genera". So you can't blame us for that - it was them sabre-toothed tigers, they come over here and take our monkeys... ;-) Alansplodge (talk) 19:14, 12 January 2020 (UTC)
- Although that greatly predated the extinction of other primates as RuslikZero's comment implied [1]. BTW this study [2] (news article discussion [3]) came to the conclusion that the main factor in the extinction of the European great apes was a failure to adapt to the food supply after deciduous trees replaced evergreen due to their existing dietary adaptations. Nil Einne (talk) 21:12, 12 January 2020 (UTC)
- Note to the OP that as per that article and ape, barbary macaques aren't apes under the most common modern definition of the word despite barbary ape being another common name. Nil Einne (talk) 21:12, 12 January 2020 (UTC)
- The Curious Case of the Last ‘Wild’ Monkeys in Europe says that the Gibraltar "apes" were once thought to have been a remnant of the European population which is known to have existed, but recent DNA analysis suggests that they all come from either Morocco or Algeria. There was a large scale reintroduction from Algeria in 1944 (apparently at the instigation of Winston Churchill) in support of the superstition that the extinction of the monkey colony would mean the end of the British Colony. Alansplodge (talk) 14:03, 13 January 2020 (UTC)
- Our article on Oreopithecus, an ape that lived in Italy 7 or 8 million years ago, says that "When a land bridge broke the isolation of the Tusco-Sardinian area 6.5 million years ago, large predators such as Machairodus and Metailurus were present among the new generation of European immigrants and Oreopithecus faced quick extinction together with other endemic genera". So you can't blame us for that - it was them sabre-toothed tigers, they come over here and take our monkeys... ;-) Alansplodge (talk) 19:14, 12 January 2020 (UTC)
- There should have been more than enough time for nonhuman primates to move back into the rest of Europe and Asia since the ice ages. Thus, there must be some factor which keeps them from moving north. The obvious difference is the climate. While it gets somewhat cold in Japan, it certainly gets far colder in northern parts of Europe and Asia. The central regions of Europe and especially Asia, not having temperatures moderated by air coming off the ocean, can also suffer from extreme temperature variations. But there are certainly some regions of Europe, like southern Italy, where the climate would be acceptable to many primates. So, some other explanation is needed there, perhaps hunting from prehistoric humans or predation from animals such as dogs. NonmalignedNations (talk) 04:54, 12 January 2020 (UTC)
- I am not sure that there have been enough time for monkeies to repopulate Europe since the last Ice Age. After all they can not swim long distances. Ruslik_Zero 05:29, 14 January 2020 (UTC)
- Primitive humans also couldn't swim long distances, yet managed to populate the Americas following the last ice age. There may well have been later waves of immigration using boats, but the first waves seem to have been by land bridge from Asia. NonmalignedNations (talk) 04:55, 15 January 2020 (UTC)
What in common to all vitamins B group (except for water solubility)?
editI see that all vitamins B group are water soluble (but also vitamin C is). So I'm interested to know the reason that all vitamins in B groups name with the letter B. 93.126.116.89 (talk) 18:56, 11 January 2020 (UTC)
- Formerly some of them had other vitamin letters. Vitamin B2 was vitamin G. Vitamin B7 was vitamin H. Vitamin B9 was vitamin M. And vitamin B3 was vitamin PP. But there is no vitamin B4 or vitamin B8. Georgia guy (talk) 19:00, 11 January 2020 (UTC)
- Our B vitamins article says that as a class, "Each B vitamin is either a cofactor (generally a coenzyme) for key metabolic processes or is a precursor needed to make one." That article notes that there are substances formerly known as B4 and B8. DMacks (talk) 19:08, 11 January 2020 (UTC)
- Thank you, but also vitamin C and vitamin K are cofactors for key metabolic processes. I really don't understand the citation from the article. 93.126.116.89 (talk) 04:51, 12 January 2020 (UTC)