21

Just Chat! / Re: Man suffocates to death from blocked nose during sleep.

« on: 14/10/2023 07:57:35 »

Yes and no! Chronic sleep apnea  (signalled by persistent loud snoring) is associated with cardiovascular insufficiency and symptomatic heart disease, and mouth breathing can be obstructed when unconscious (hence the need to clear the tongue when starting artificial respiration) so it is quite possible that the guy may indeed have suffocated, particularly if he had taken any sedative medication (including alcohol) that suppressed his gag reflex. 

So it's quite likely to be an indirect effect of acute nasal restriction exacerbating a chronic condition. There are plenty of cases where chronic apnea is associated with sudden death when asleep, but the opinion varies as to precise causality.

 

22

Physics, Astronomy & Cosmology / Re: Which bit of the Shell theorem is not working?

« on: 14/10/2023 07:44:46 »

This seems to come down to the question of whether an infinite homogeneous medium can be considered spherically symmetric. Not "from the inside" because of course there is no "outside" if it is infinite.

Rather than wander off into the barren land of philosophy, we can say that anywhere close to our origin is indeed spherically symmetric because it is homogeneous, and anywhere further away becomes increasingly less significant as we increase r, so as r → ∞  the effect of regions > r cannot become less symmetric. 

23

Physics, Astronomy & Cosmology / Re: Which bit of the Shell theorem is not working?

« on: 13/10/2023 22:04:59 »

We'll have a perfectly uniform distribution of Hydrogen gas spread out over space  AND  we'll also assume that space is infinite.   [NOTE:  It is not necessary or guaranteed that the universe is or was infinite,  that doesn't matter, for this hypothetical situation we are having an infinite space].    For a star to form, some hydrogen has to clump together under gravity and form an overdense region of Hydgrogen.

Eppur si muove (Galileo)

24

Physics, Astronomy & Cosmology / Re: Which bit of the Shell theorem is not working?

« on: 13/10/2023 17:40:42 »

But by definition is isn't locally homgeneous. All the particles are moving at random, so the particle density at any point will vary over time from less than the mean to more than the mean, and if D_loc > D_mean you can get gravitational agglomeration.

25

Physics, Astronomy & Cosmology / Re: Which bit of the Shell theorem is not working?

« on: 13/10/2023 16:50:51 »

BC beat me to it by 30 minutes (I was asleep in the garden).

26

Geek Speak / Re: Complaint about Windows 11

« on: 13/10/2023 12:39:53 »

I now find if I've submitted a post here and press End it invites me to add a reply!

27

Geek Speak / Re: Complaint about Windows 11

« on: 13/10/2023 10:09:22 »

Not sure that clicking "start" to switch something off is a good idea. "End" is at least logical, though the "end" button on my keyboard doesn't seem to do anything and there isn't a visible software END on the screen.

However I agree that there was nothing wrong with XP, and I'm annoyed that my flight simulator  won't work on anything later. It's almost as infuriating as the latest "upgrade" to this forum, that renders practically every nonalphanumeric symbol as ? unless you type multiple ?s  in which case it generates some stupid childish cartoon.

28

Physics, Astronomy & Cosmology / Re: What happens to the surplus electrons after an alpha decay?

« on: 08/10/2023 22:00:57 »

At some point during the evolution of the cosmos, most planets were indeed smaller than a grain of salt. But the density of beta emitters was very small indeed.

29

Physics, Astronomy & Cosmology / Re: What happens to the surplus electrons after an alpha decay?

« on: 08/10/2023 17:20:54 »

What fraction of the alpha particles can actually escape?

Not a lot, but we are in no hurry - this is cosmology! However to speed things up you might consider a tiny grain of an energetic beta emitter like Yttrium-90.

30

Physics, Astronomy & Cosmology / Re: What happens to the surplus electrons after an alpha decay?

« on: 08/10/2023 14:19:48 »

Thes energy involved in expelling an alpha is enormous compared with the ionisation energy of any atom you can think of, but this does raise an interesting question in the very long term. Suppose we have a planet composed entirely of alpha emitter: at what point does the internal coulomb repulsion overcome the binding energy of the delocalised electrons and blow the chunk of metal apart?

31

Physics, Astronomy & Cosmology / Re: What happens to the surplus electrons after an alpha decay?

« on: 08/10/2023 08:39:13 »

The remaining atom is indeed ionised, and an insulated lump of any alpha or beta emitter gradually acquires a charge of opposite sign to the emitted particle. 

32

Physics, Astronomy & Cosmology / Re: Reckoning Sunrise And Sunset.

« on: 05/10/2023 18:56:39 »

"Daylight" is separately defined by the  Civil Aviation Authority as 0.5 hour before sunrise to 0.5 hour after sunset, these times being the appearance and disappearance of the upper perimeter of the sun above the horizon. 

33

COVID-19 / Re: Corona impact?

« on: 30/09/2023 23:42:48 »

Nor anywhere else. What remains obvious is the increase in COVID infections every time the quarantine rules were relaxed  in the UK. 

34

General Science / Re: Infinity...

« on: 30/09/2023 12:23:30 »

Apologies. What a twit I am. No excuse.

35

Just Chat! / Re: Is there a universal moral standard?

« on: 27/09/2023 10:23:47 »

Very few of our northern ancestors survived the ice age, and they did so by migrating, as did their predecessors during the previous hot period. No amount of AI is going to persuade humans to behave rationally, and there are now too many of us to permit significant migration without famine and war. Some will indeed survive, with or without AI, but it won't be pleasant.

36

General Science / Re: Is it safe to eat cake that's been frozen for 11 years?

« on: 26/09/2023 19:56:15 »

when did neilep cease to be human and become a sheep?

'Twas ever thus, methinks.

37

COVID-19 / Re: Is CoV2 finding new ways to kill?

« on: 26/09/2023 19:53:59 »

Can the differences between excess mortality and covid deaths be down to reporting differences?

Almost certainly. Covid mortality is a matter of opinion, excess mortality is a matter of fact.

38

Physics, Astronomy & Cosmology / Re: Weird physics with a guitar string

« on: 10/09/2023 19:56:02 »

One of the joys of living in an old barn is the accessibility of the most basic item of physics lab kit - an oak roof beam, replete with rusty nails and ancient bolts. I'm tempted to to the experiment myself!

39

Physiology & Medicine / Re: What's causing the cancer increace in the UK?

« on: 07/09/2023 08:24:34 »

The team behind the study analysed data from the Global Burden of Disease 2019 Study for 29 cancers in 204 countries and regions.......

There were 1.8 million new cancer diagnoses for under-50s in 2019 - an increase of 79.1% since 1990 - with deaths also up by 27.7%.

So the statistics are meaningless.

For instance: the population of India has grown fairly linearly since 1970, from 400,000 to 1,400,000,000, childhood mortality and communicable disease incidence have declined, and diagnostic services have improved. So it's no surprise that the number of deaths in middle age from any diagnosis has increased between 1990 and 2019, and the fact that it is less than 300% is remarkable.

40

Physiology & Medicine / Re: Should pills always be taken with a full glass of water?

« on: 01/09/2023 13:28:39 »

Back to the question, then.

I don't think the object of the water is primarily that of precise dilution, but more likely to ensure that the pill reaches the stomach or wherever it is supposed to be, without getting lodged where it shouldn't, or gets dissolved  so as to be extracted by and dispersed in liver/kidney/bladder/other wobbly bit,  as required. If so, one glass with several pills will do the job, as long as the pills themselves are compatible and don't have to be taken in a specific time sequence.