21

Physiology & Medicine / Re: Why Make Scar Tissue Instead Of Bog-standard Tissue To Heal ?

« on: 14/05/2024 16:02:27 »

My knowledge in this area is rudimentary and wooly:  when damage occurs the first responders are cells of the immune system( neutrophils, macrophages, lymphocytes etc) to deal with any microbiologic intruders and these are followed by fibroblasts. Fibroblasts are immature fibrin producing cells which lay down a mechanical barrier to seal the area- otherwise consequences would be devastating with the amount of hostile agents in the environment. To replace identical tissue  new cells of the correct type would have to generated by mitosis of competent progenitor cells and would take too long, the fibroblasts are much faster.   

22

Physics, Astronomy & Cosmology / Re: Observing Quantum Entangled particles At the Same Time . What Happens ?

« on: 13/05/2024 19:10:18 »

To solve that conundrum we have invoke the Lamb shift!!  sorry Neilep, I couldn't resist, I have no clue as to the answer as it is well above my pay grade.

23

Physics, Astronomy & Cosmology / Re: Why didn't the total solar eclipse strain my naked eyes at all?

« on: 09/04/2024 13:50:30 »

Looking directly at the sun is inherently hazardous and something one should never do. Just because it did not hurt does not imply it was safe to do so. I am sure you have seen the effect of direct sunlight through a lens setting fire to a piece of paper- now consider the same effect directed at the fragile retina at the back of your eye. Damage may have been done only to show later.

24

Physics, Astronomy & Cosmology / Re: Does time dilation and length contraction apply to light?

« on: 07/04/2024 10:38:10 »

Krytptid's thoughts here mirror mine very closely and it seems I have a major gap in my understanding of SR(not surprising really). If one could travel at the speed of light surely one's rapidity would be infinite and hence time and space would have no existence- why does this not apply to light?. I have heard several physicists state that "light does not experience time or space" or something similar expressed more accurately: I cannot remember any names other than the mathematician Roger Penrose(who can be controversial at times). This question of mine is a bit muddled but I could not find a better wording. 

25

General Science / Re: Is Absolute Zero Possible?

« on: 04/04/2024 20:38:17 »

Just the same as trying to accelerate a massive object to the speed of light, we can get arbitrarily close by expending more and more energy but we can never get to the target speed. Similarly with absolute zero the closer one gets the harder it becomes to produce a further decrease. Mathematically one can only asymptotically approach either the speed of light(with mass) or absolute zero. |Oh dear Eternal Student beat me to it!

26

New Theories / Re: Could quantum mechanics be wrong?

« on: 18/03/2024 09:27:20 »

"Could quantum theory be wrong?", yes of course it could be wrong, as could any theory. However quantum theory has been stunningly successful in explaining observations and making predictions and to debunk it would require a better theory and I see nothing on the horizon. Quantum theory is counterintuitive and baffling but that in itself does not make it wrong.

27

Physics, Astronomy & Cosmology / Re: Gas discharge tube hydrogen

« on: 17/03/2024 22:12:33 »

Hi ES, I would have said 1Mv/m for normal air but I could be wrong. Many discharge tube use additional methods to start the initial ionisation, prior to avalanche occurring such as heated filaments in florescent lamps, a high voltage external conductor in xenon flash tubes and an auxillary electrode very close to one of the main electrodes in mercury vapour lamps(to start a local ionisation). High pressure sodium lamps and tin halide lamps use a high voltage source in series with one of the electrode supplies. The gas pressure plays a major role in the voltage needed to initiate ionisation, referred to as the strike voltage: the higher the pressure, the higher the necessary voltage and a lot of discharge lamps have to cool down after power interruption before reuse as the pressure is higher when hot. Many other factors may account for the discrepancies in the calculations: random cosmic rays as you suggested or low level radionuclides. Field emission as raised by Alancalverd may play a role(wild assed guess).   

28

Physics, Astronomy & Cosmology / Re: How many spots are produced from Stern-Gerlach apparatus that rotates?

« on: 16/03/2024 13:49:27 »

I remember this experiment from my long distant college days but I had forgotten it's name. I can't add anything of value, I do however have a question: how are the silver atoms entrained in a beam? the only way I can think of is electrostatic acceleration, that would lead to charged particles which are ruled out by the terms of the experiment.

29

Physics, Astronomy & Cosmology / Re: What is the Hopf gauge?

« on: 11/03/2024 22:11:16 »

I managed the rubik cube ONCE, but could never repeat it.

30

That CAN'T be true! / Re: Is HCQ the antidote to Trump?

« on: 11/03/2024 22:04:04 »

It is likely that improvements in genetics will in the future allow a prescriber to know which medications will have the most beneficial effects and the minimum of side effects--the so called "personalised medicine". We are not there yet. As regards hydroxychloroquine the eye damage is a direct effect of the medication on SOME people and it has nothing to do with covid. All medications for autoimmune conditions have serious and sometimes severe(including lethal) side effects. Quite apart from this any drug, even the humble aspirin, can have unexpected dire effects. I know a person who having taken an aspirin developed an anaphylactic reaction and whose life was saved by a local doctor who happened to be at home at the time.

31

New Theories / Re: What caused inflation?

« on: 28/02/2024 19:06:29 »

"What caused inflation?" Bad monetary policy obviously (sorry!!)

32

Just Chat! / Re: What is the difference between Beer, Lager and Ale?

« on: 27/02/2024 09:14:34 »

You are all forgetting porter, the black stuff, as in Guinness. The colour, as far as I know, comes from a large quantity of malt used in manufacture. Beer is my favourite drink although I rarely exceed two drinks these days as opposed to my misspent youth when I drank all alcoholic drinks to excess.

33

Physics, Astronomy & Cosmology / Re: Can plutonium exist naturally in the universe?

« on: 25/02/2024 18:32:08 »

The half life of the longest lived plutonium isotope is too short for any substantial quantities to exist given the age of the earth. As 0rigin has pointed it is found in trace amounts.

34

Technology / Re: What are the assumptions of the hydrogenic model in semiconductors?

« on: 25/02/2024 09:56:38 »

Hi ES, I read your post yesterday around midday but I was rather busy at the time so I did not reply. I certainly agree that Alan is an excellent contributor. However I doubt if I can be of any value as my semiconductor theory(50 years ago) was extremely rudimentary as opposed to semiconductor application. I have a query peripheral to yours and I hope I am not digressing too much: the permittivity of a material is a bulk property that is due to polarisation of charges within that material--does this have a real meaning at the atomic scale?,  ie  is it not just a case of vacuum permittivity+ whatever electrostatic effects are occurring locally?  Another conundrum for me is why electron and hole mobility varies when a hole is effectively an electron moving in the opposite direction, step by step. Apologies if this is too much off topic. 

35

Physiology & Medicine / Re: Washing Your Hands After You Pet Your Cat.

« on: 16/02/2024 20:39:14 »

Petro, I have seen that precise manoeuvre being performed by a cat. It is an indication of worm infestation and the cat does it due to anal irritation from the worms- administer anthelmintics pronto.

36

Physiology & Medicine / Re: Washing Your Hands After You Pet Your Cat.

« on: 15/02/2024 12:37:08 »

We(the boss and myself) run a small scale cat shelter and do a small amount of tnr work. I invariably wash my hands after any cat handling: dry hands is a small price to pay to avoid toxocara, toxoplasmosis and other unspecified zoonoses.

37

General Science / Re: Can there be water on the moon?

« on: 14/02/2024 11:30:21 »

Janus, I accept what you say regarding comets but my confusion remains. Lyophilisation is commonly used to remove water from solutions where heating may degrade a product. I suppose the real question is why do comets and other icy bodies not undergo sublimation?

38

Physiology & Medicine / Re: Can General Anaesthetics Cause Diabetes?

« on: 11/02/2024 19:30:11 »

That is a bizarre constellation of symptoms. I can't see any anaesthetic being responsible and I don't see the remotest connection with diabetes. I would reckon some other factor is responsible. Again I emphasise what has previously been said-an internet forum is not the place for medical advice. I would suggest you do some doctor shopping until you find a sympathetic and understanding practitioner-this may require multiple consultations until you find one that takes you seriously and is competent with complex cases. As regards your problems with the NHS, I can't comment as I live in Ireland.

39

Physics, Astronomy & Cosmology / Re: If Andromeda is red shifted how can we collide with it?

« on: 09/02/2024 19:16:01 »

Have I found an error here, Halc?(shock, horror). You state an object approaching an observer will be red shifted relative to a stationary case- surely you mean blue shifted?

40

Chemistry / Re: Is halogenation of alkynes with propylene glycol possible?

« on: 09/02/2024 19:03:39 »

Hi, ES, I had a brief look at that article you posted. I was horrified to find ethylene glycol was found in some samples of fluid. Glycerol and propylene glycol are relatively safe but ethylene glycol is definitely not suitable for use in a product that is consumed. When I say glycerol and propylene glycol are relatively safe what I mean is that ingestion of either is considered quite safe but vaporising either may not be: both of these substances are quite capable of producing toxins if sufficiently heated. I too picked up the noxious habit of smoking for a short while in my 20's-30's, long since dropped. I always missed my nicotine and my solution is nicotine gum.