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Physiology & Medicine / Re: What is different between fast talkers and normal people?
« on: Today at 12:30:14 »
"The rich are different from us"
"Yes. They have more money."
"Yes. They have more money."
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COVID-19 / Re: Is this a useful parameter?
« on: Yesterday at 18:07:55 »Quote from: alancalverd on Today at 15:46:07It shouldn't have - it's their definition!
That sentence will have triggered a “caution” response in numerate readers, and a howl of derision from anyone who has travelled in a crowded train.
I suspect that just generated a sigh from any passing epidemiologists.
The problem is that idiot politicians parade it (and some gullible punters accept it) as a measure of progress in "defeating" the disease. My whole point is that your decision whether to go to work on a bus should not be influenced by a global statistic of everybody doing everything, which includes suicidal Republicans and anti-vaxers holding crowded hate-ins, but something specific to your choice of action and environment.
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That CAN'T be true! / Re: False info on the Pyramids of Giza
« on: Yesterday at 17:58:11 »Forgot to mention: When Pliny The Elder arrived in Giza one of the things which astounded him was that not a single tailing (stone chips) could be found nearby nor were any chisel-marks present on the stones of the Great Pyramid of Giza.Suggests it was saw-cut, or maybe the sharp edges had been eroded by 2500 years of sandstorms, which certainly defaced the Sphinx.
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With the tremendous amount of stone involved the size of the quarry would be hundreds of feet in depth, miles in circumference.Or, to be precise, the volume of the pyramid. Archimedes Principle was true long before Archimedes was born!
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The question is not only how the Egyptians could have transported the stones but how they got them out of the depths of the quarry using rope.Contracted the work to the Neolithic Britons, who had already been doing it for about 3000 years.
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And where is this huge quarry?Wherever the stone came from - ask a geologist.
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They had to have been manufactured in situ.Never a good idea. There's no evidence of major cutting and forming at Stonehenge or any other megalith. Why carry rubbish from A to B and back again, or schlep your saws from one building site to another? Unless you want raw stone for a rockery, every professional quarry supplies material cut to size. The clever bit is writing the specification.
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Let's travel to the Valley of The Kings where numerous labyrinths were cut into the rock with precision. Some were hundreds of feet in length. What happened to the mountains of debris? I am also reminded of a letter in The London Times where a reader fascinated by Howard Carter's "discovery" wondered how the Egyptians lighted the "tomb".If you have to tunnel through hard rock in 2500 BC, you will find a ready market for your waste as road dressing, flood defences, small building blocks, or ship's ballast. Spoil heaps are a consequence of mining (particularly soft rock, for coal) rather than tunneling, where the target material is a lot more valuable than the waste. In a well-integrated command economy you can plan your roads and flood defences alongside your tunneling activities. Pity we can't always do so nowadays, though I believe that Crossrail spoil has made a few football pitches on marshland (but sadly not enough to replace those turned into car parks for the London Olympics).
Not sure about lighting, but I guess they had discovered fire. Olive oil lamps burn fairly clean and you can make good candles from animal fat. Unlike coal mining, you don't have an explosive problem with flames in rock buildings.
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COVID-19 / Is this a useful parameter?
« on: Yesterday at 15:46:07 »
Apologies for a long post, but it's something I've had in mind for some years and seems very appropriate right now.
It is doubly unfortunate that epidemiologists have chosen the symbol R to denote the “effective reproduction number” of an infective agent, and politicians have seized upon R as an indication of viral virulence, or their “success” in controlling a pandemic.
For anyone unacquainted with the terminology, R is the average number of persons infected by a single carrier of a disease. That sentence will have triggered a “caution” response in numerate readers, and a howl of derision from anyone who has travelled in a crowded train. If the specific infectivity of a virus is constant, R is obviously dependent on the behavior of the carriers, not the virus: RCOVID = 0 for a hermit in a desert, maybe 20 for someone who sneezes his way around the London Circle Line at 8 am.
As shown by experiment, there is no scientific justification for relaxing social distancing or quarantine rules when R decreases: doing so merely allows it to increase again. And R is an average of the entire population exposed by all recent behaviors including total isolation: it does not indicate the likelihood of any individual becoming infected at a particular time and place. R is an effect, not a cause or a decision parameter.
Why doubly unfortunate? Because some years ago I proposed a risk index R as a means of communicating risk to the public, and the present COVID pandemic demands a simple, efficient parameter that can be used for public information and emergency planning. So in deference to the World Health Organisation, I’d like to relaunch the risk index with the Cyrillic symbol Я (pronounced Ya).
Define Я = 10 + log10 P where P is the probability of an event.
If the event is inevitable, P = 1 and Я = 10
If the event is so unlikely that no living human will see it, Я < 0.1
The logarithmic scale is actually familiar to the public and consistent with our intuitive appreciation of risk. Winds of Beaufort force below 4 are of no consequence. Force 5 is inconvenient, 6 is mildly hazardous and 10 is “seldom experienced inland” with trees uprooted and major structural damage. Likewise the Richter earthquake scale: up to 4 is of scientific interest, 5 – 6 causes recoverable damage and anything above 8 is a disaster.
In everyday life we consider Я ≤ 5 “worth it” for the fun or benefit. The UK annual risk index for death in a road accident is about 5, but deep sea fishing with an annual ЯDEATH approaching 7 is a dangerous profession in northern waters.
My original interest was in efficiently communicating the risk of diagnostic x-rays. The natural incidence of cancer gives Я<DEATH|CANCER> ≈ 9.4 (no apologies to this audience for Dirac notation, and I’m sure Joe Public will get the idea pretty quickly). Against this, we have Я ≤ 4 for a dental x-ray (negligible – could save you pain and infection, and safer than driving to the clinic) and 7 for a repeated abdominal CT (worth the risk to avert a greater one).
In a pandemic, I think honest public information demands activity-specific values of Я<Y|X> , the risk index of an individual contracting Y whilst doing X. Early in the UK outbreak I cancelled a biannual jazz concert on the estimated Я<COVID|GIG> of 8.4 (unacceptable, however good the band) given the likely size and packing density of the audience and the probable local incidence of infection. I take no pleasure in being right in this instance – by the original date, two members of the prospective audience of 100 were indeed infectious, one becoming very seriously ill a few days later.
It should be possible to estimate and publish general Я values for, say, working in an office, a ventilated factory, or an outdoor team, and travelling to work by bus or train. You can subtract an appropriate value for each type of face mask. Those of a social science bent might study crowd behavior in theatres, pubs etc and on beaches, and estimate appropriate Я values that would be far more meaningful and specific than the current global R that allegedly “informs” political decisions. Individuals can then make properly informed choices about their work and leisure.
It is doubly unfortunate that epidemiologists have chosen the symbol R to denote the “effective reproduction number” of an infective agent, and politicians have seized upon R as an indication of viral virulence, or their “success” in controlling a pandemic.
For anyone unacquainted with the terminology, R is the average number of persons infected by a single carrier of a disease. That sentence will have triggered a “caution” response in numerate readers, and a howl of derision from anyone who has travelled in a crowded train. If the specific infectivity of a virus is constant, R is obviously dependent on the behavior of the carriers, not the virus: RCOVID = 0 for a hermit in a desert, maybe 20 for someone who sneezes his way around the London Circle Line at 8 am.
As shown by experiment, there is no scientific justification for relaxing social distancing or quarantine rules when R decreases: doing so merely allows it to increase again. And R is an average of the entire population exposed by all recent behaviors including total isolation: it does not indicate the likelihood of any individual becoming infected at a particular time and place. R is an effect, not a cause or a decision parameter.
Why doubly unfortunate? Because some years ago I proposed a risk index R as a means of communicating risk to the public, and the present COVID pandemic demands a simple, efficient parameter that can be used for public information and emergency planning. So in deference to the World Health Organisation, I’d like to relaunch the risk index with the Cyrillic symbol Я (pronounced Ya).
Define Я = 10 + log10 P where P is the probability of an event.
If the event is inevitable, P = 1 and Я = 10
If the event is so unlikely that no living human will see it, Я < 0.1
The logarithmic scale is actually familiar to the public and consistent with our intuitive appreciation of risk. Winds of Beaufort force below 4 are of no consequence. Force 5 is inconvenient, 6 is mildly hazardous and 10 is “seldom experienced inland” with trees uprooted and major structural damage. Likewise the Richter earthquake scale: up to 4 is of scientific interest, 5 – 6 causes recoverable damage and anything above 8 is a disaster.
In everyday life we consider Я ≤ 5 “worth it” for the fun or benefit. The UK annual risk index for death in a road accident is about 5, but deep sea fishing with an annual ЯDEATH approaching 7 is a dangerous profession in northern waters.
My original interest was in efficiently communicating the risk of diagnostic x-rays. The natural incidence of cancer gives Я<DEATH|CANCER> ≈ 9.4 (no apologies to this audience for Dirac notation, and I’m sure Joe Public will get the idea pretty quickly). Against this, we have Я ≤ 4 for a dental x-ray (negligible – could save you pain and infection, and safer than driving to the clinic) and 7 for a repeated abdominal CT (worth the risk to avert a greater one).
In a pandemic, I think honest public information demands activity-specific values of Я<Y|X> , the risk index of an individual contracting Y whilst doing X. Early in the UK outbreak I cancelled a biannual jazz concert on the estimated Я<COVID|GIG> of 8.4 (unacceptable, however good the band) given the likely size and packing density of the audience and the probable local incidence of infection. I take no pleasure in being right in this instance – by the original date, two members of the prospective audience of 100 were indeed infectious, one becoming very seriously ill a few days later.
It should be possible to estimate and publish general Я values for, say, working in an office, a ventilated factory, or an outdoor team, and travelling to work by bus or train. You can subtract an appropriate value for each type of face mask. Those of a social science bent might study crowd behavior in theatres, pubs etc and on beaches, and estimate appropriate Я values that would be far more meaningful and specific than the current global R that allegedly “informs” political decisions. Individuals can then make properly informed choices about their work and leisure.
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Plant Sciences, Zoology & Evolution / Re: Do Doggies Prefer To Socialise With Doggies Of Their Own Breed ?
« on: Yesterday at 15:36:05 »
I've always had gundogs - sensible size, natural-looking animals bred for a cooperative temperament whether as workers or assistance dogs, and completely unconcerned with loud noises (though I fit "mutt muffs" in a plane - they look really cool with aviator sunglasses!). Being pretty average size they tolerated most others but in a free-running dog park they always seemed to associate first with other gundogs (spaniels, retrievers, pointers, and standard poodles) in preference even to other working dogs like terriers, collies and vizslas.
That said, their dogonalities were still individual. One really friendly and placid golden retriever would not associate with any curly-haired dog and despite living in a houseful of kids, spontaneously attacked just one human - a quiet little girl with curly hair. No harm done but most embarrassing and inexplicable. A trainee guide dog puppy disliked stairs: whenever I took her to a shopping mall with an escalator, she very determinedly dragged me to the lift (she did eventually relent, and passed out with honour). Two retrievers disliked cats to the extent that they attacked a stone statue of a cat each time we walked past our neighbour's house, whilst another liked to share her bed and go hunting with our resident moggies.
That said, their dogonalities were still individual. One really friendly and placid golden retriever would not associate with any curly-haired dog and despite living in a houseful of kids, spontaneously attacked just one human - a quiet little girl with curly hair. No harm done but most embarrassing and inexplicable. A trainee guide dog puppy disliked stairs: whenever I took her to a shopping mall with an escalator, she very determinedly dragged me to the lift (she did eventually relent, and passed out with honour). Two retrievers disliked cats to the extent that they attacked a stone statue of a cat each time we walked past our neighbour's house, whilst another liked to share her bed and go hunting with our resident moggies.
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Physiology & Medicine / Re: Why Do We Sometimes Miss A Word Out When Writing A Message ?
« on: Yesterday at 15:09:34 »
Your mouth and brain move quicker than your fingers. Mouth keeps pace with brain, brain assumes fingers are in step.
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Physics, Astronomy & Cosmology / Re: Can windmills affect Earth's rotation?
« on: Yesterday at 15:07:55 »Well, since you are sticking with your idea that the wind can slow down the rotation of the Earth in the long run... you.Please don't ascribe irrelevant ideas to me.
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New Theories / Re: Is conservation of angular momentum properly understood?
« on: Yesterday at 14:11:52 »
The energy of a skater's rotation (½Iω2) is conserved, along with his angular momentum Iω. Arms in or out alters the moment of inertia I (= ∫mr2) and thus rotational speed ω.
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Physics, Astronomy & Cosmology / Re: Can windmills affect Earth's rotation?
« on: Yesterday at 14:00:59 »(Hint; it's not atmospheric drag; there isn't a 1000 MPH wind running round the equator)Now who's being silly? "Wind" is air moving over the ground. The surface air at the equator is moving 1000 mph faster than that at the poles, but neither mass is moving very fast over the ground. Now if we take a sample of equatorial air and adiabatically move it 1 degree north, it will be travelling over the ground at about 11 mph. The same volume of air moving 1 degree southward from a northern latitude will be travelling on the opposite direction. That is the origin of geostrophic wind: the north-south movement of air masses is due to temperature differential (cold dense air sinks below warmer air, so the surface drift is from pole to equator), and the east-west movement is due to coriolis force.
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That CAN'T be true! / Re: False information on amphibians
« on: Yesterday at 00:26:59 »
Ah yes. Amphibians. As observed by Tommy Cooper:
Bloke walks into a bar with a lizard on his shoulder. Points to the lizard and says "A pint for me and a gin for Tiny". Barman says "Why do you call him Tiny? " "Because he's my newt."
Beware, AR, you are trading bullshit with professionals here.
Bloke walks into a bar with a lizard on his shoulder. Points to the lizard and says "A pint for me and a gin for Tiny". Barman says "Why do you call him Tiny? " "Because he's my newt."
Beware, AR, you are trading bullshit with professionals here.
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Just Chat! / Re: My great-great grandfather, the draft dodger...
« on: Yesterday at 00:12:56 »
It wasn't all bad. Halliburton shares rose spectacularly which is why Dick Cheney (former CEO of Halliburton) started the war. And guess who got the contract to supply all the logistics and support services, right down to emergency rations, to the US military, and rebuild the oilfields afterwards?
I often wondered why the Coalition gave 3 months notice of intent to invade (not an ultimatum or threat, as in Desert Storm, but precise notice of an irrevocable decision). Not the best military tactic, but time to get the contracts sewn up before the killing started. That's not war, it's murder.
I often wondered why the Coalition gave 3 months notice of intent to invade (not an ultimatum or threat, as in Desert Storm, but precise notice of an irrevocable decision). Not the best military tactic, but time to get the contracts sewn up before the killing started. That's not war, it's murder.
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General Science / Re: What caused the whistling sounds of bombs?
« on: 02/08/2020 23:56:06 »
Beware of Hollywood. Even in the most factual of documentaries you will see and simultaneously hear the explosion of bombs filmed from the air. If you were flying at 30,000 ft and 300 mph, (a) you wouldn't hear much above the noise of the engines inside your pressurised cockpit or full-face oxygen mask and headset, and (b) by the time the sound travelled 30,000 ft upwards you would be 2.3 miles away. On the receiving end of an artillery shell, you might just hear the gun fire a few milliseconds before the shell hit you. The psychological effect of a V1 flying bomb engine cutting out 10 - 20 seconds before impact is worth comparing with the supersonic (thus silent) ballistic descent of a V2 rocket. Fortunately I have no memory of either.
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Physics, Astronomy & Cosmology / Re: Can windmills affect Earth's rotation?
« on: 02/08/2020 23:24:38 »
The prevailing geostrophic wind is the result of coriolis force making the air move relative to the surface of the earth. The coriolis force is a consequence of the spin of the earth. If we extract kinetic energy from the geostrophic wind and dissipate it as heat, whence came that energy? The only source is the spin of the earth.
The function of a vehicle brake is to convert the kinetic energy of the vehicle to heat. Same thing. Conservation of momentum means that applying the brakes whilst airborne will stop the wheels spinning but won't dissipate much energy, but if they are in contact with the ground (a very large mass) you can generally bring the vehicle to a standstill.
The function of a vehicle brake is to convert the kinetic energy of the vehicle to heat. Same thing. Conservation of momentum means that applying the brakes whilst airborne will stop the wheels spinning but won't dissipate much energy, but if they are in contact with the ground (a very large mass) you can generally bring the vehicle to a standstill.
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Physiology & Medicine / Re: Are All Instances Stored As A Memory, However Banal.
« on: 02/08/2020 23:07:08 »
Chances are that we synthesise plausible memories in response to some triggers, and polish the synthesis with other memories. This seems to happen under friendly interrogation of a witness: "What happened next? Can you remember what happened before...." and an entire scene gradually emerges that is at least plausible and possibly accurate, though as has often been demonstrated, quite significant chunks may be missing - the classic "gorilla experiment" is a fine example where the implausible doesn't even register in the short-term memory.
The video game is a potential clue too. What you see in a video game has no implications for real food, real sex or real fighting, so it does not make plausible connections with the deepseated things that matter. I've looked at methods of teaching people to take x-rays. If they study the science, pass the theory test, then x-ray real patients, they generally forget the theory within a year, but where we have first taught the practical side and coached a student through a real patient episode, the later theory tends to stick. Or, as the medics say, "See one, do one, teach one."
The video game is a potential clue too. What you see in a video game has no implications for real food, real sex or real fighting, so it does not make plausible connections with the deepseated things that matter. I've looked at methods of teaching people to take x-rays. If they study the science, pass the theory test, then x-ray real patients, they generally forget the theory within a year, but where we have first taught the practical side and coached a student through a real patient episode, the later theory tends to stick. Or, as the medics say, "See one, do one, teach one."
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Just Chat! / Re: My great-great grandfather, the draft dodger...
« on: 02/08/2020 20:02:20 »
Almost certainly.
But truth is a strange thing. Prime Minister Tony B Liar told us that the Iraq invasion wasn't about regime change, and two weeks later Foreign Secretary Jack Man O'Straw said it was. Even though they were career politicians, they can't both have been lying, surely?
Not that we will ever know. In the course of 7 years of vastly expensive public inquiry, Lord Chilcot never actually asked them which one was lying. Far be it from me to suspect either of telling the truth.
But truth is a strange thing. Prime Minister Tony B Liar told us that the Iraq invasion wasn't about regime change, and two weeks later Foreign Secretary Jack Man O'Straw said it was. Even though they were career politicians, they can't both have been lying, surely?
Not that we will ever know. In the course of 7 years of vastly expensive public inquiry, Lord Chilcot never actually asked them which one was lying. Far be it from me to suspect either of telling the truth.
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Physics, Astronomy & Cosmology / Re: How Do We Know Absolute Zero Is The Temperature It Is If It's Unattainable ?
« on: 02/08/2020 13:48:34 »Absolute zero is the lowest temperature possible........
How do we know this if Absolute Zero Is unattainable ?
Make up your mind!
Anyway, the concept is derived from the Carnot efficiency equation for a perfect heat engine, η = 1 - Tcold/Thot.
For any nonzero value of Tcold, η < 1, and we can measure the efficiency of real heat engines and show that they follow this law.
So we can hypothesise a zero value of temperature and an absolute scale such that any heat engine with a cold source at T =0 would have η = 1
The problem is one of "thermal relativity". If we have a hypothetical heat sink at T = 0 and a heat source at 0 + δT, the efficiency with which we can extract energy from it decreases toward zero as δT → 0 so we need to expend an infinite amount of energy to cool it to T = 0.
The idea that there is no motion at T = 0 contradicts Heisenberg, as we would then be able to predict the momentum (zero) and position (right here) of a particle, with zero indeterminacy.
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Physics, Astronomy & Cosmology / Re: Can windmills affect Earth's rotation?
« on: 02/08/2020 11:54:35 »
OK
The spinning Earth has enormous rotational KE.
But it can't transfer that energy without slowing itself down.
And it can't slow itself down without an external torque.
Now, the geothermal energy, and the tides might make small contributions but they really don''t do "weather".
So, the fundamental question for you to answer Alan, is this.
Are you abandoning the conservation of energy, or abandoning the conservation of angular momentum?
Apologies - I hit "modify" instead of "quote", but I think it's clear what you were referring to.
For the sake of public safety, please publish the registration number of your car, as you say the brakes don't work.
And how sad that James Joule wasted his honeymoon.
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Physics, Astronomy & Cosmology / Re: Light speed and refractive index.
« on: 02/08/2020 11:44:52 »
Elementary geometry of a plane wave shows that sin(a) / sin(b) = va/vb, if I recall O level physics from 60 years ago. Nothing hypothetical about it.
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Physics, Astronomy & Cosmology / Re: Can windmills affect Earth's rotation?
« on: 02/08/2020 00:08:35 »Not a lot. Solar heating is responsible for the slow, gross convective movement of large air masses towards and away from the poles, but the formation of cyclones is powered by the coriolis displacement of those masses. The wind in the Southern Ocean is almost entirely due to the earth's spin as there is almost no land to produce differential heating, which is why albatrosses live the way they do, reliant on a constant westerly to keep them airborne for years at a time.gnoring second-order effects such as thermal winds, the source of kinetic energy is the rotational energy of the planet, so it must eventually stop spinning.And there was me thinking that the Sun powered the wind.
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Physics, Astronomy & Cosmology / Re: Do planets rule our destiny?
« on: 01/08/2020 23:58:15 »Eventually, if we keep reproducing and finding cures for disease, we will run out of potable water (i.e. rain) and start killing each other for access to the habitable bit between high tide and desert.If it all hangs together nicely,
Are we likely to find that this situation is related to human relationships?