exchemist

I had read he was a merchant trading goods through to the Mediterranean. Seems likely to me he did quite a lot of travelling. But it is all very obscure, certainly.

Not much passed through Mecca though. More likely Mohammed brought ideas back from his travels to the North. (I admit to being attracted to the “revisionist” school of Wansbrough et al, as it seems to me relatively objective and historical, whereas so much of what is presented as the history of Islam is suffused with the tradition of believers, which cannot often be corroborated.)https://en.wikipedia.org/wiki/John_Wansbrough

Yes I know but the religion did not spring, fully formed, from Mohammed.

I think it arose in the c.5th, probably in Mesopotamia, out of the mix of Judaism, Christianity and other influences. I came into contact with it when I lived in the Middle East. It can engender a very attractive, calm and gentle attitude in its adherents (men and women). But of course in its strident militant form it is just as bad as the Puritanism of old in the Christian world, or even worse. So as with most religion, it can have both positive and negative aspects.

I find difficulty making sense of this.

Well no, in general valence band electrons can't tunnel. The barriers are too high and too thick. You would need very special circumstances for tunnelling to be possible, I think.

Well then, if they are localised in the valence band they won't participate in superconducting behaviour, will they? I'm not a solid state physicist but my understanding is conduction requires a continuum of delocalised states, so that there is no energy gap to be jumped when an electron is given a bit of extra energy.

But if they fall into a localised state (presumably of lower energy if they "fall" into it) they cease to be conduction electrons, surely? In effect they go into the valence band, don't they?

For these to be “conduction electrons”, wouldn’t the state have to extend throughout the crystal? But would they then be treated as paired?

There is an article in today's Financial Times, saying that the European space industry is also going down the route of commercial competition. So yes, this is a natural progression, once a technology has been sufficiently mastered and once commercial exploitation opportunities open up in the field in question. It was not so long ago that nuclear power was all in state hands. But now, it no longer is. But the private sector needs a return on investment that justifies the level of risk in the enterprise. Where there is little or no commercial return, and/or the risks are high, private enterprise will not get involved. Private enterprise may also be denied access to a sector if there is no prospect of effective competition (anti-monopoly legislation). So these are the areas where governments have to step in. I am honestly not sure I understand what point you want to make, apart from having some kind of animus against NASA.

If this becomes its unofficial name I shall be highly gratified. It does resemble its creator, rather: Bezos should avoid roll-neck sweaters at all costs.😄

It does, thanks. Looks as if my organic chemistry tutor might just have been becoming aware of this around the time I sat finals.🙂

Do you know when this reagent was introduced to the organic synthesis arsenal? I learned my organic synthesis back in the 1970s and I don't have a record of this one in my undergraduate book (ROC Norman) from that era, though it does of course have the dichromate method you mention. I see from Wiki this chlorochromate route was discovered "by accident" but there does not seem to be any information about when and how this came about. I wonder if it is more recent than my old books.

Probably from this: https://en.wikipedia.org/wiki/Pyridinium_chlorochromate

Yes you must have misunderstood, I think. It is populations of organisms that evolve, collectively, rather than single individuals spawning a whole new species. If it were the latter it could only happen by extreme in-breeding, which we know doesn't work out well.

What point of discussion do you wish to raise? Or are you just spamming?

Who?

I think with Big Pharma the problem is the Cinderella areas. They can make billions out of cancer but some of these 3rd world conditions barely get a look in because there's no money in it for them. We obviously need both approaches.

I think Big Pharma will be speaking of innovation in the sense of product development rather than ab initio research. Product development is extremely costly - and high risk.

What about Starlink, then? https://en.wikipedia.org/wiki/Starlink But I’m now confused as to what you are arguing for. It’s clear that private enterprise can do a good job of research when there is an identifiable commercial goal. But it is equally clear that other, more fundamental, types of research are also needed for science to progress. Governments have always realised this, which is why state-funded research programmes continue to be supported. None of this is new.

Have you not heard of Elon Musk’s Space X? https://www.spacex.com

The government, at least in the UK, does fund a certain amount of research done by organisations such as universities and the Natural History Museum.

The Man Who Haunted Himself?

Yes. My understanding is that collisional broadening, or pressure broadening, is also due to the uncertainty principle as the collisions shorten the lifetime of the excited state. But it's an interesting question @sethoflagos poses. The expectation values of energy e.g. of an ensemble, are conserved of course, but whether that is strictly so for an individual pair of absorption and re-emission events by the same atom I feel less confident.

I think there is also broadening due to the Doppler effects of random atomic motion, at least in gases.