1

Just Chat! / Re: If religion gives one comfort is it...

« on: Today at 14:30:46 »

Just like any other addictive substance, it's difficult to get excited by what people do to themselves, but important to defend third parties against the actions of addicts.

If someone finds solace in selfdeception, no problem, but if he uses it as an excuse to harm others, or even feels inclined to induce others to use it he must be stopped.

It is no concern of mine what anyone believes, injects or shoves up his nose, but the teaching and preaching of religion to others should be illegal, and there shold be no concessions in law, taxation or expectation of civil behavior on grounds of a professed faith.  That said, my Jewish relatives in Quebec always register as Catholic because they get a local tax concession for the education budget.

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Technology / Re: Could a microwave be used to heat a home?

« on: Yesterday at 16:18:21 »

The rate of heating is directly proportional to volts x amps, so to get the same power from a 12 volt unit, you need 10 times the current that you would use in a 120 volt unit. Higher voltages are preferred because you lose less power in the transmission lines.

If you have solar power, consider using a heat pump and a big hot water storage tank, and also underfloor low temperature (30 - 35 degree) heating rather than traditional 50 degree "radiators" (actually convectors) - "low and slow" is best if your property is adequately insulated.

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

« on: Yesterday at 16:09:42 »

The Trolley Problem should never be dismissed as an academic exercise.  Churchill's decision not to evacuate the Calais garrison in 1940 is a classic case of balancing the certain death of a few against the possible survival of many by delaying the German advance on Dunkirk. Imagine sending this signal:

Every hour you continue to exist is of the greatest help to the B.E.F.   Government has therefore decided you must continue to fight. Have greatest possible admiration for your splendid stand. Evacuation will not (repeat not) take place, and craft required for above purposes are to return to Dover. Verity and Windsor to cover Commander Mine-sweeping and his retirement.

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Question of the Week / Re: QotW - 18.11.11 - Why are propeller-drive planes popular in hurricanes?

« on: 15/11/2018 17:55:44 »

But not a Hurricane. Though more tolerant of bullet damage than a Spitfire, it doesn't take well to tailsliding or any reverse flow over the control surfaces.

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Technology / Re: Could a microwave be used to heat a home?

« on: 15/11/2018 17:46:17 »

The cost of domestic electricity is the same whatever means you use to heat the house, except by night storage heaters,where you can use offpeak tariffs. All electric heaters are almost equally efficient with the exception of electrically powered heat pumps, which use about 30% of the energy of a direct (resistive or microwave) heater.

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Physiology & Medicine / Re: What Causes Infection Post Cataract Surgery?

« on: 15/11/2018 16:02:22 »

Tears are good, but not always effective.

There's a good reason for scrubbing and gloving before touching a patient. Beware of poking a nonsterile finger anywhere near an eye - even one that hasn't been traumatised by surgery.

I'm not an ophthalmologist, but  a basic rule of industrial first aid is "don't muck about with eyes". If it isn't healing every day, and in your case that seems to be so, take yourself to an eye clinic ASAP. I expect to be free of itching within a week and fully recovered in a month, with strict instructions to return to the clinic if not.

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Just Chat! / Re: The DOGMA of science........

« on: 15/11/2018 15:49:06 »

Science is a recursive process: observe, hypothesise, test.

Scientific knowledge is the residue of explanatory and disprovable hypotheses that have not been disproved.

That's all there is to it.

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Physics, Astronomy & Cosmology / Re: Do aliens exist in other galaxies? Have they come to visit earth?

« on: 15/11/2018 11:47:23 »

Are there  extragalactic life forms? Probably.

Have they visited Earth? Probably not.

The pyramids were built by slaves in the service of human stupidity.

Stone circles were built by tradesmen for business.

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

« on: 15/11/2018 11:42:41 »

But there's your problem - there is no universally applicable rule! Witness the ecstatic joy of the Hitler Jugend, and the total misery they wrought on everyone, including, eventually, themselves.

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Physiology & Medicine / Re: What Causes Infection Post Cataract Surgery?

« on: 15/11/2018 08:22:03 »

Welcome to the club - I've just joined for the second time (right eye this week) and am reliving the joys of antisepsis.

Tears and eye drops drain into the nasal cavity and thence to the throat, so it is entirely possible that bacteria in the mouth or jaw can travel in the opposite direction if there is insufficient flow of antiseptic or natural tears.

There's an equally odd connection between dental infection and the heart: bacterial endocarditis usually begins with a dental abscess.

I guess any bug strong enough to withstand saliva and attack a tooth, is a potential guerrilla.

As for a cure, rule 1 applies: "never google symptoms"! Always go back to the eye clinic and do whatever they say - they've seen it all before.

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Chemistry / Re: Can you calculate the speed of particles participating in a chemical reaction?

« on: 15/11/2018 08:05:29 »

The heavier Group 1 metals react more violently. Li just oxidises, Na floats and fizzes, K gets hot enough to ignite the expelled hydrogen, Rb metal melts with the heat of reaction, and Cs explodes on contact with water. I don't think anyone has looked at the hydrolysis of bulk francium.

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

« on: 15/11/2018 07:58:11 »

The "golden rule" is subject to sampling error.

It is fairly obvious that a "family" group (could be a biological family or a temporary unit like a ship's crew) will function better if its members can trust each other. The military understand this: selection for specialist duties includes checks for honesty and recognition that you are fighting for your mates first, your country second. So the "greatest happiness for the greatest number" (GHGN) metric is fairly easy to determine where N < 50, say.

Brexit provides a fine example of the breakdown of GHGN for very large N. There is no doubt that a customs union is good for business: whether you are an importer or an exporter, N is small and fewer rules and tariffs means more profit . But if the nation as a whole (N is large) imports more than it exports, increased business flow overall means more loss, hence devaluation and reduced public budgets.  At its simplest, you could model a trading nation as consisting of just two businesses of roughly equal size and turnover N_imp ≈ N_exp. Good news for any sample of size ≤ 2N is bad news for the whole population if  N_imp > N_exp by even a small amount, hence the interesting conundrum "EU good for British business, bad for Britain".

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

« on: 14/11/2018 13:54:51 »

I think Alan's post only shows that morality can be subjective, but doesn't show that it can't be collective. If some moral standards can be shown to be universally applicable, that will answer the question of the topic.

I spend some time sitting on medical research ethics committees. The general guidance seems to boil down to whether the balance of risk and benefit has been fully evaluated and presented such that the famous "man on the Clapham omnibus" would be able to make an informed decision to participate. But in making that judgement, we are often aware that even his brother on the Brooklyn omnibus has a slightly different perspective, and we can only guess at what the average Tokyo commuter might consider acceptable.

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

« on: 14/11/2018 13:39:10 »

"An eye for an eye, a tooth for a tooth" is nowadays considered by Jewish philosophers as a simplistic misinterpretation of "to the value of an eye....", that is, promoting restorative rather than retributive justice, but the underlying theme is always justice and caution* rather than forgiveness. My father told the story of a Jewish doctor treating a dying ex-SS patient who asked "can you forgive me", to which he answered "Being human, I can forget or ignore, but forgiveness is a matter for your god". I consider that a logical starting point, but those brought up in other faiths may think otherwise.

Intriguingly I find something in common between Jewish and Celtic law, where the individual is held liable without limit for his actions and the state exists to serve the citizen by prosecuting wrongs;  in contrast to Roman law where the citizen exists to serve the state and is granted rights in exchange, and its latterday substitution of absolution and penitence for sacrifice.

Not that I have much time for faith. As Dawkins pointed out, the only common theme among religions is that each teaches you to despise all the others.




*"Hit me once - shame on you. Hit me twice - shame on me." - sounds sharper in Yiddish, but I 'm a bit rusty.

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That CAN'T be true! / Re: Why are we redefining the kilogram?

« on: 14/11/2018 08:11:39 »

BIPM is situated in the Parc de Saint-Cloud, at Sèvres, in the suburbs south-west of Paris.
Postal address: Pavillon de Breteuil, F-92312 Sèvres Cedex

Which was in France the last time I looked.

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

« on: 14/11/2018 08:05:39 »

Without delving too deeply into the definition of morality or ethics, I think we can usefully approach the subject through "universal". The test is whether any person considered normal by his peers, would make the same choice or judgement as any other in a case requiring subjective evaluation.

This immediately  leads to a sampling question. "Turn the other cheek" would be considered normal and desirable in some peer groups, whilst "an eye for an eye" might be de rigeur for others. Both strategies have evolutionary validity: think rabbits, which outbreed their predators, and lions, where only the strongest male gets to breed.

Homo sapiens is an odd creature We breed too slowly to survive as prey, and are too weak to be predators, but a very complex collaboration allows us to farm and hunt all we need. That said, although we can see the value of large scale collaboration (like bees and ants) it takes a long time to acquire the knowledge and skills needed to participate, so the small "family" unit (including communes and kibbutzim) is a prerequisite of survival.

Thus we grow up with at least two loyalties, to the immediate family that supports us, and to the wider community that supports the family. No problem if we have infinite resources and unlimited choice, but the decisions we make in restricted circumstances are what defines our morality, and it is fairly clear from daily accounts of religious wars and magistrates' court proceedings that either  there is no universal concept of right and wrong, or that it can be set aside for personal gain.

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Physics, Astronomy & Cosmology / Re: Reactionless Drives Possible ?

« on: 13/11/2018 20:55:14 »

Momentum is a vector. Energy is not. Momentum is conserved.You need to alter the momentum of an object to make it move. You can't do this by jumping around inside it.

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That CAN'T be true! / Re: Why are we redefining the kilogram?

« on: 13/11/2018 20:48:54 »

The real reason is to steal the kilogram from the untrustworthy French and have it defined by a British invention, along with the cesium clock.

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The Environment / Re: Is there any hope of effective action on climate change?

« on: 13/11/2018 20:40:37 »

And a few centuries earlier. A couple of years ago, there were reports of plants being uncovered by a retreating glacier https://www.smithsonianmag.com/science-nature/plants-frozen-under-a-glacier-for-400-years-can-come-back-to-life-81837981/

This made all the headlines about global waming, anthropogenic diasaster, etc., but few if any mentioned the obvious fact that the glacier wasn't there 500 years ago and, since bryophytes are very slow-growing, it probably wasn't there 600 or 700 years ago either. So in at least one part of Canada, the climate has been at least as warm as it is now, within the span of well-recorded history.

Just read an interesting slightly futuristic novel "The Ice"  by Laline Paull that sets out the economic benefit of the disappearance of arctic ice.

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Question of the Week / Re: QotW - 18.11.11 - Why are propeller-drive planes popular in hurricanes?

« on: 13/11/2018 15:44:18 »

Wind speed is unimportant once you are airborne - a plane flies relative to its ambient air, not the ground.

Choice of plane depends on the precise mission. If you want to explore a small part of the sky, a low stall speed (and a fairly benign stall characteristic) will give you a tighter turn radius: most small prop planes stall at 60 kt or less, but bizjets tend to drop out of the sky at 80 or more, and can be a handful to recover from a spin. If you are interested in turbulence, you'll want a ship with good aerobatic capability (+10 -5 g at least)  which is not what bizjets do best. At low levels, you won't expect much icing in a hurricane, and props are more economical than jets below 10,000 ft.  Some prop aircraft are known to be good ice carriers at higher altitude but for routine exploration above 15,000 ft a turboprop or pure jet comes into its own.

Piston engines are generally more tolerant of short flights with widely varying power demand from loiter via "75% cruise" to "120% combat" and in the event of an encounter with hail or flying debris, a propeller is a lot cheaper to repair than a jet fan. Jets really don't like starting, stopping, or loitering: think retrievers and greyhounds!.