Recent comments in /f/askscience

aztronut t1_j6kdc2v wrote

Reply to comment by Narrow_Competition41 in Why is wind energy generation greater during the night? by ZeroTheHero524

The Sun heats up more of the atmosphere when the incoming rays are tangent to the surface, such as at the terminators at twilight, than when the incidence is normal to the surface, and it is also normal to the atmosphere. This extra energy in the atmosphere at twilight typically results in greater wind speeds.

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turnpikelad t1_j6jhupl wrote

Reply to Has a new animal species evolved since mankind’s existence? by coding_ac

One super-clear example of speciation since the emergence of humans is polar bears. They only diverged from brown bears around 100 thousand years ago, and some of the more significant morphological changes apparently date from just the last 10000 years.

(According to wikipedia at least.. https://en.wikipedia.org/wiki/Polar_bear#Taxonomy_and_evolution )

It's fascinating because it doesn't seem like any other animal in the history of the planet had thrived in that particular niche (large land mammal mainly living on sea ice as a predator of marine species).

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cowsruleusall t1_j6ivsa8 wrote

Reply to can gemstones be melted into a gradient? by Acceptable_Shift_247

Gemcutter here, with a background in synthetic gems and crystal chemistry (am actually in medicine but I'm a rock nerd lol). What you're asking for isn't possible, as one of the commenters has noted.

But, something else is. There are purple sapphires, which have a very similar colour to amethyst and even have similar pleochroism to amethyst. There are also blue lab-grown sapphires. One manufacturer is currently growing synthetic sapphires that have alternating bands of blue and purple.

If you're not particularly attached to the idea of amethyst, and are okay with amethyst-coloured sapphire instead, you could get one of these pieces.

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LinguisticsTurtle OP t1_j6iqy4h wrote

Reply to comment by Beginning_Cat_4972 in What makes it difficult to determine whether nutrient deficiencies are implicated in mental-health issues like ADHD? by LinguisticsTurtle

>I skimmed a few papers and there's not a lot of rational behind the idea that vitamin deficiencies play a role in ADHD pathogenesis.

Isn't there some data showing correlation (not necessarily causation of course...people with poor self-regulation might have a poor diet for obvious commonsensical reasons) between low nutrient levels and ADHD?

Aren't nutrients implicated in all sorts of brain functions including ones related to mental-health issues, hence the burgeoning field of nutritional psychiatry?

What about the seemingly (to a layperson) straightforward experiment of just giving ADHD patients who are (e.g.) low in iron (or whatever) some iron and seeing if symptoms improve?

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annomandaris t1_j6iq1pz wrote

Reply to comment by djublonskopf in Has a new animal species evolved since mankind’s existence? by coding_ac

Yes, I mean as far as Ive read, the wolf/dog ancestor split into 2 wolf types. One was the ancestor of wolves that would become the wolves as we know them today, and the other was a wolf that would eventually be domesticated, and become something like a husky/malamutes, and eventually the rest of dog species.

So while wolves have been bred with dogs at several points in history, it’s not quite accurate to say dogs came from wolves (the ones we know today). They came from other wolves.

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Zeniphyre t1_j6ibcr5 wrote

Reply to Can you (roughly) determine the dosage of a drug taken based off of the blood concentration? by bynarie

Yes and no.

I'm finishing up a doctorate in pharmacy and the thing is that there are soooo many factors that go into drug blood concentrations. Genes, the drug in question, diet, underlying conditions, kidney function (hard to tell when they are deceased), etc. All play a factor in drug concentrations.

We do however have basic pharmacokinetics diagrams that can apply to a lot of drugs across large populations. Most of the time they are very basic equations though, usually only considering age, weight, height.

There isn't really a perfect answer here.

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GalFisk t1_j6i7ffp wrote

Reply to Does illness remain in population "just by never going away"? by BlackWardz

Some diseases also jump species. Animals can give humans rabies, but humans generally don't pass it on. These often stick around in species that don't get sick, or don't get nearly as sick, as we do. And some can linger, for example anthrax which can sit around in soil for decades, just doing nothing.

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