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This made me remember my love for health sciences and pathophysiology. I was so busy with reading self improvement books (thinking I was not good enough) that I forgot to improve my knowledge in the sciences (which is what I'm already good at). You have just made me less depressed ❤️

Yes, that would be fair. If you check the prevailing winds from the north east, Iran, and the zagros mountains stops most of the humidity coming from there.

I was thinking of the gulf states/Saudi Arabia. So is it fair to say they don't see much rain because the rain clouds fall in Iran instead?

I'm more thinking of around the gulf States and red sea. The water and air isn't cold there is it?

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Geez you should be an astrophysicist ;) this is an excellent breakdown, do you have any articles or papers you recommend (or published) on the early universe that focus on expansion history and the emergence of cosmic structures?

> There isn't believed to be anyone left in the Americas or Tasmania who does not have any European ancestry from the last 500 years.

OK, but take the Andean's great-to-the-nth grandmother from 7300 years ago (one of the ones who lived in the same region all those centuries ago). Is that grandmother also an ancestor of the teacher in Somerset? And of some villager in a remote village in Tibet?

I assumed that Alice measures a 1 because the argument would be the same no matter what she measures. Just replace the 1 with -1 and the logic still works. (Basically, "without loss of generality"). Or, I could have some variable X that represents Alice's measurement. We don't know X until Alice actually performs the measurement, but I think the argument should still work if we just replace all instances of 1 with X. I'll have a look at that Veritasium video, thanks for mentioning it.

Neuroscience PhD here: Dopamine does different things in different places. Asking why one group of dopamine releasing neurons can't substitute for another is like saying "my toilet valve is broken, but the valve in my shower is fine, so shouldn't my toilet work anyway?"

Dopamine releasing neurons in the substantia nigra and the dopamine releasing neurons in other areas have 1 thing in common, which is the neurotransmitter they use. But what neurotransmitter they use is relatively unimportant to their function. What's far more important is what neurons they get input from, how those inputs are processed, and what neurons they connect to.

Any given group of neurons that releases dopamine can only release dopamine where their axons are, and that dopamine cannot freely diffuse throughout the brain. This is the whole point of synapses: to help confine the spread of neurotransmitters so that neurotransmitters can act as signals from one neuron to another instead of broadcast signals.

If this seems like a significant departure from how you're used to thinking about neurotransmitters, GOOD. Neurotransmitters do not have functions, neurons do. Repeated with emphasis: NEUROTRANSMITTERS DO NOT HAVE FUNCTIONS, NEURONS DO. Two different neurons can use the same neurotransmitter for totally different functions. Dopamine, for example, is also used in the control of lactation, which is totally unrelated to its role in the control of movement.

>For example, usually yearly vaccines contain a couple of A strains and a B strain, whatever was most prevalent in the other hemisphere 6 months ago.

This bit of vaccine logic has never made sense to me given the speed of flu virus mutation. I mean you can get over the flu in a couple of weeks but then soon after pick up a brand new mutated strain. But it takes 6 months to pump out a vaccine for one set of strains that odds are are obsolete by now and one's body is already immune to through natural exposure?

I mean I understand what you're saying that there are virus sets in the vaccine one wouldn't necessarily run into but still. 6 months seems to be an awfully long lag time compared to the flu's mutatuon rate and even human natural immune response and adaption rate. So yeah this particular bit of logic never made sense.

But please if you have a sensible counter argument for why someone with a functioning immune system should bother then I'm listening.

Why this is relevant is your above explaination seemed to take yearly flu innoculation for granted.

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Mmmm, yes, decarboxylation, I'm definitely familiar with this term for legitimate reasons.

Many coronaviruses that are extremely closely related to SARS-CoV-2 have been found in bats - both before the COVID outbreak, and after.

Coronaviruses in bats don’t tend to exist as clear, unambiguous, stable populations. There’s extensive recombination and rapid evolution, and the many small semi-distinct populations of bats means that there are many small, transient populations of coronaviruses in these populations.

On top of that, it’s probable that SARS-CoV-2 isn’t strictly a bat virus - coronaviruses recombine rapidly and readily, and recombination with a non-bat coronavirus is likely for both SARS and SARS-CoV-2 (pangolins, in the case of SARS-CoV-2). So there’s no reason to believe that SARS-CoV-2 exactly ever circulated in bats.

So the notion that it should be easy, or even possible, to identify exactly the same virus in bats over many years is obviously mistaken. Nevertheless, many very close relatives of SARS-CoV-2 have been found in Asian bats, including several that seem to be very capable of replicating in humans and that share the receptor specificity of SARS-CoV-2.

> We found that the receptor-binding domains of these viruses differ from that of SARS-CoV-2 by only one or two residues at the interface with ACE2, bind more efficiently to the hACE2 protein than that of the SARS-CoV-2 strain isolated in Wuhan from early human cases, and mediate hACE2-dependent entry and replication in human cells, which is inhibited by antibodies that neutralize SARS-CoV-2. … Our findings therefore indicate that bat-borne SARS-CoV-2-like viruses that are potentially infectious for humans circulate in Rhinolophus spp. in the Indochinese peninsula.

-Bat coronaviruses related to SARS-CoV-2 and infectious for human cells

It’s important to remember that there are vast numbers of bats, and that they have been very superficially sampled. In spite of this, it’s been very easy to find these close hits, showing that these very dangerous, human-preadapted viruses are very common in bats.

Virologists have been warning about this for decades, specifically calling out that the next pandemic was likely to arise from bat coronaviruses. It shouldn’t be surprising that the prediction actually came true.

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