Kin Selection

I agree that the overall system is probably too large, but we are talking specifically about the flagship university of the UC system. arguably the best public university in the world, and it is getting hurt just as bad as UC Riverside. that's absurd and embarrassing.

Maybe it has something to with the fact that the state of california has cannibalized the funding for my beloved alma mater.

this is only getting media attention because twitter is "hip" these days. supernova hunters don't care how they get tipped off about a new burst, and all kinds of avenues result in rapid assessments. i've heard of text messages, emails, you name it. we have a system for rapidly alerting the supernova community based around email, i doubt that twitter will replace it.

the interesting and cool thing about this is that alex happened to be at keck when the news came through, which allowed him to quickly point the monster scope at m51. supernova usually last for months and months, but it is rare for us to get such early data with such powerful machines. it can only really happen randomly.

we make crazy hybrid clones all the time.

my guess is that you have something along the lines of calcium carbide in those rocks

that's what statistically means. in the long run, in the absence of a selecting force to promote the stability of a beneficial trait, genetic drift will tend to disable neutral traits. this is especially true when 1) the genetic sequences underlying the trait need to be very precise for the trait to function properly (much more important in receptor/effector systems than in gross physical traits) and 2) the sequences are rather long. thus, we can assume that this receptor does not represent a neutral trait, especially because it directly involves a phenotype that is intimately tied to survival (breathing).

if you had read my entire comment, you would have noticed that I said the exact same thing. and not all neurotransmitters are bitter (ie basic), just most. the weird thing is that the neurotransmitters that we know contract the bronchioles (eg acetylcholine) are also predicted to be bitter compounds. strange stuff indeed.

Genetic drift would not explain why it developed in the first place, and would not be sufficient to keep a complicated receptor/effector system intact in a large, heterogeneous population such as ours for very long (in genetic terms). most people misunderstand the term.

/degree in genetics and genomics

i use reasoning in an abstract sense to mean "biological driving force." but you already knew that.

I wonder what might be the reasoning behind this system evolving/remaining intact in humans. I can't really think of an exogenous substance that we inhale naturally that would activate such a response and confer an advantage to us. My best guess would be that the natural ligand for these receptors is something that is produced locally in the lungs in scenarios where bronchiodilation is desired (ie sympathetic stimulation). as someone else pointed out, many of the common neuroreceptors are alkaloids, and would probably activate these receptors. From the abstract, it sounds like these receptors are Gq (IP3 and calcium) receptors, which is interesting because the "classic" receptors that dilate the smooth muscle in the lungs are Gs receptors that stimulate increased cAMP. In smooth muscle, more calcium generally leads to stronger, not weaker, contraction. cAMP leads to relaxation, explaining why epinephrine and albuterol have their effects.

didn't have time to read the whole paper. exam on this stuff tomorrow though, wonder if I can use this on an essay question?

/med student

talk about a crappy experimental setup. no way to control for all the things that could explain this result.

these kinds of hand-wavy experiments will continue to crop up as our ability to measure the brain outstrips our ability to understand.

it's way to easy to point an fMRI at a region "linked" to a particular behavior or type of thinking, and then wax poetic about what the increased activity may or may not mean. sad coming from a relatively respected lab.

there is a moderate amount of smooth muscle found in the venous system. from what I have been taught (only in my first year of medical school), these muscles are not under the same kind of highly-specific nervous system control that the muscle in arteries is under. ie, your body has a hard time selectively contracting/relaxing specific veins. these muscles are predominantly under hormonal control, meaning that their contraction is regulated at a body-wide level.

the vast majority of control over where blood flows in the body is at the level of arterioles, which are small arteries found before capillary beds.

not always, just when the correction is trivial and doesn't contribute to the understanding at hand. isn't hyperbole ("always") a more dangerous use of language? so much for respect.

to be completely accurate, arteries do indeed 'deliver' blood, as they are responsible for the distribution of the blood to the body. feel free to pop open oed, which I'm sure a doctor of your caliber has at the ready, if you doubt me.

additionally, the elastic quality of the major arteries allows for pumping of blood outside the heart, which more closely fits with your highly specific (but in the context of the discussion at hand, meaningless) definition of deliver. and let's not forget the smooth muscle around arteries which can contract, leading to yet another form of active 'delivery' of blood.

thanks for your career advice, doc. it has been taken to heart.