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

« on: Yesterday at 23:22:04 »

So I give a warning shot and the two vigilantes who have apprehended a mass murderer, let him go. Is this in tune with the universal moral standard?

The sole function of a commercial-breed chicken is to be eaten. Developed over millennia from fairly rare forest dwellers, they are now the most numerous warmblooded creatures on earth. My next development project will, I  hope, be to enhance chicken fattening for the benefit of vegans by harvesting wild locusts to feed to chickens, and thus reduce the damage to vegetable crops - now there's a moral conundrum!

As for a "wasteful" process, my aunt remarked, during a celebratory feast, "If it wasn't for Jewish weddings, the country would be overrun with chickens".

Goal requires the existence of at least one conscious being.
Terminal requires the perspective from distant future.
Universal requires that no additional arbitrary constraint is applied beyond those already attached to the words goal and terminal.

Sadly, that doesn't state what your UTG is, and actually makes it undefinable. Here I am as a conscious being, but I have no way of reviewing or judging anything from the standpoint of the near future, never mind the distant one! The only references I have are historical data and personal aspirations. 

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COVID-19 / Re: Are there any trials that involve deliberately infecting someone with the virus?

« on: Yesterday at 23:04:20 »

Agreed (I sit on an ethics committee).

We have plenty of people with active COVID at various stages from "recently infected" to recovered or dead, adequate evidence of how it is transmitted, and a wide variety of expressions from "active but asymptomatic" to very dead.

It is very unusual to grant research ethics approval to any procedure with more than 0.1% known risk of fatality, and even in those cases there must be a probable benefit to the participant - usually patients with a terminal prognosis. In the case of COVID infection we have an overall 5% risk of fatality, with a much higher risk (probably ~20%) in the definable groups who are likely to benefit most from prophylaxis. The additional scientific benefit would be negligible as there is no shortage of extant  cases at all stages of disease and still a few uninfected controls, though the number is decreasing rapidly as governments play politics instead of tackling the pandemic.   

Sadly, and entirely due to governmental incompetence, the disease is sufficiently widespread and infective that "treat and release" will suffice to demonstrate the effectiveness of any experimental prophylaxis.   

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COVID-19 / Re: Do young people get COVID more mildly because they've had fewer infections?

« on: Yesterday at 15:47:31 »

Three conflated notions in the OP.

Yes, a bit of exposure to dirt in childhood is essential to prime the immune system, and if you've never grazed a knee you won't learn to take care in late life.
But

kids don't contract the diseases/infections we used to

is due to the eradication of most infectious diseases, vaccination, hygiene, and nutrition.

COVID primarily impairs respiration. If you have generally good health and plenty of "spare" lung capacity you may recover, or even not notice a temporary decrease in  capacity, but if your cardiopulmonary function is only marginal and you have difficulty breathing when recumbent (eg from obesity or general lack of muscle tone) you are likely to decline and probably die from some other respiratory disease such as pneumonia .

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

« on: Yesterday at 11:21:53 »

But in my example the only sure way to stop the killing without possibly getting yourself killed, is to shoot somebody.

I will probably eat hundreds of chickens in my lifetime, and then die. Does that increase or decrease progress towards your universal goal?

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COVID-19 / Re: Does wearing a mask make a difference if you're standing 2 metres away?

« on: Yesterday at 11:14:41 »

Once you are wearing a mask, you are wearing it regardless of the subsequent behavior of others.

You can't rely on the kindness of strangers to protect you, and there are plenty of infectious idiots about who don't know or don't care what 2m looks like. Including the President of the United States and his Senate majority, and the unelected President Cummings of the UK.

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

« on: 30/06/2020 20:42:54 »

That's very Buddhist, but doesn't address the everyday moral question of whether to kill a conscious being for food, or to prevent oneself being killed.

And here's another version of the trolley problem. Two men are attacking one man, and look certain to kill him. You have a gun. What do you do?

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General Science / Re: The Start of Time?

« on: 30/06/2020 16:09:41 »

1) We assume that the axiom: ‘can’t get something from nothing’ holds - an assumption that is supported by the law of conservation of energy.

Physical laws are approximations to consistent observation, that is, they are descriptive, not prescriptive, and they evolve as we discover things about the universe. It's a convenient axiom for many purposes, but contradicts the Big Bang hypothesis and its supporting observations.

Also nothing permanent can exist in time - 2nd law of thermodynamics.

I think not

The second law of thermodynamics states that the total entropy of an isolated system can never decrease over time, and is constant if and only if all processes are reversible.

In plain language, if you don't kick it, it won't bite you.

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General Science / Re: The Start of Time?

« on: 30/06/2020 15:59:59 »

Time can have a zero, and indeed whether you use the Common Calendar, the Ethiopian Calendar, or the Julian Calendar, there is always a zero date and nobody (except religious nutters) gets excited about "negative" dates. If you want an "absolute" calendar you can set zero at the Big Bang, the only unique feature being that, unlike BC/AD, right now we have no idea what (if anything) may have happened before then.

Whether the observable universe was created ex nihilo or by a spontaneous eversion of some previous universe is immaterial, If there was change when t < 0 then time existed; if not, it was irrelevant. 

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Just Chat! / Re: UK seasonal death trends

« on: 30/06/2020 13:11:50 »

Particularly so if you hasten the departure of the elderly this week: you will have fewer expected deaths next week. 

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COVID-19 / Re: Why are daily new cases so periodic?

« on: 30/06/2020 13:00:47 »

Has absolutely nothing in your life changed? I doubt it, unless you are a hermit with a self-sufficient smallholding (or an Ocado account*) and no friends. Everyone else in the developed world (i.e. excluding the USA) has had to adjust in some way, and most of Africa is catching up.

Whilst US citizens have mostly gone about their daily lives shooting one another and praising the Lord, a considerable number (as reported by the OP) have coughed, lost their jobs, been shot for wearing/not wearing a mask,  or died, and the bars in Texas and Florida are losing money.

*come to think of it, the nice young men who wash your helicopter while you shop at Waitrose, no longer valet the interior, so nobody is completely unaffected.

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COVID-19 / Re: Why are daily new cases so periodic?f

« on: 30/06/2020 11:24:20 »

Since the initial symptoms are mild, most people will finish a week's work  before reporting for testing. Hence the Friday peak in reported cases.

You can assume that very little paperwork gets done at the weekend. The cause of death must sometimes be verified by a consultant if the initial certificate was issued by a junior doctor, but Friday is golf day and committees pray together (IIRC they have no other useful function) on Mondays. Most jurisdictions allow 3 to 5 days to record a death, so Wednesday is the day for reporting known COVID deaths.

These graphs underline how the conflation of delayed symptoms and political stupidity have led to the dominance of  this interesting virus over all human thought and action.

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Physics, Astronomy & Cosmology / Re: What is the difference in APPLICATION of characteristic and continuous spectrum?

« on: 29/06/2020 23:04:46 »

We don't use the entire continuous spectrum for radiography.  Low energy photons are absorbed in superficial tissue so contribute to skin burning but not to image formation. High energy photons penetrate further through tissue but discriminate less between low atomic number (low Z) and high Z absorbers, so you get less contrast between bone (containing calcium and phosphorus) and soft tissue (mostly carbon and water). So we limit the x-ray tube voltage to less than 150 kV and remove the low energy part by filtration through aluminium or copper, leaving a spectrum with a peak intensity around 40 - 70 keV which forms the most useful images for general radiology. A tungsten anode yields a fairly clean initial continuous spectrum (the characteristic lines at 60 keV are a small fraction of the useful energy) that can be tailored to the  thickness of the part to be x-rayed by simply altering the tube potential.

In mammography we are trying to image subtle differences in soft tissue density and pick out tiny calcifications. This is best done with a very narrow spectrum to minimise surface dose (from a low energy component) and low-contrast fog (from high energy photons).  It turns out that the molybdenum Kα characteristic line at 17.5 keV does the job very well. If we restrict the anode voltage to less than 30 kV and absorb the higher energy part of the continuum with a Mo filter, we get a beam that is close to ideal as long as we can compress the breast to minimise the overall absorption and scatter of the useful photons.

It would be really great to get rid of the low energy component altogether, but whilst a radionuclide source would give us a genuine line spectrum, the effective source diameter would be too large -  we need a point source with a high dose rate to get a sharp image.

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Technology / Re: Are there differences between radio receivers?

« on: 29/06/2020 14:32:37 »

It's all electromagnetic radiation but the components required to transmit and receive it tend to be specific to a small range of frequencies and the means by which we encode information onto the em wave, and thus the specific circuit required to decode it, also vary.

So yes, they are all radio transmitters and receivers, but assigned to and optimised for specific parts of the spectrum so they don't interfere with each other.

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Physics, Astronomy & Cosmology / Re: Is there a limit to growth^-1 ?

« on: 29/06/2020 14:25:57 »

"Things" haven't changed, but our ability to see the very large (galaxies 30,000,000,000 light years away) and the very small (atoms) and to perceive and detect even subatomic particles, has developed very rapidly in the last few hundred years.

That said, Democritus postulated atoms around 400 BC and even  the idiots enforcing Christianity insisted that the universe was a bit bigger than the Earth, even if it all revolved around the Pope. What's missing right now is any plausible hypothesis that there might be something significantly smaller than an electron, or bigger than the observable universe. It's tempting to think that a quark or neutrino might be in some way smaller than an electron, but Heisenberg intervenes and suggests that size is a bit meaningless on that scale. Likewise I'm pretty sure that there's a lot more, and a lot more interesting, outside the observable universe, but as we can't observe it (by definition) it has to remain hypothetical.

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Just Chat! / Re: When have religious gatherings been illegal?

« on: 28/06/2020 23:40:18 »

Religion and spirituality can make it harder to call others sub human.

The one thing all religions have in common is that each one teaches you to despise all the others.

The sooner the national curriculum drops "religious tolerance" in favor of intellect and logic, the better. Meanwhile, as a brief interlude in the Catholic-Protestant war, we have Sunnis and Shias killing one another and Boko Haram taking schoolgirls into slavery for the greater glory of the Abrahamic God and his Prophet. India and Pakistan having been partitioned on religious grounds, the slaughter continues from time to time.

Religion, of course, deals with eternal truths and unchanging morality. Such as whether women are fit to be priests and whether priests should molest children.

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Technology / Re: Could surplus electricity be used to extract gold from seawater?

« on: 28/06/2020 23:16:39 »

The most useful thing to extract from seawater would be clean water. Nothing else has any real value.

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General Science / Re: The Start of Time?

« on: 28/06/2020 23:14:21 »

It's a transition between quantum states. You can model it as an analog of mesoscopic movement, but it's a poor analog. The point is that it gives us a means of measuring time (units) but doesn't define time (quantity).

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

« on: 28/06/2020 18:35:44 »

Even when I'm doing nothing, I'm consuming food that could be eaten by someone or something else, and exhaling carbon dioxide.

Please remind me, in one paragraph, of your universal terminal goal, and whether we agreed on it!

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Just Chat! / Re: When have religious gatherings been illegal?

« on: 28/06/2020 18:30:56 »

Creation scientists, don't like the theory of evolution because it leads to what they think is a lesser sense of human dignity.

It's a curious form of dignity that preaches hatred of the intellect and denial of the obvious.

Evolution is not a theory, it's an everyday observation. Darwin merely hypothesised the underlying mechanism.

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Just Chat! / Re: When have religious gatherings been illegal?

« on: 28/06/2020 18:26:26 »

But the values are different if you think once you die, you cease to exist.

Plenty of atheists believe in an afterlife. And I guess a lot of priests hope there isn't one.