1

Physiology & Medicine / Re: Why where the native Americans so vulnerable to disease?

« on: Yesterday at 11:44:35 »

Eurasia was genetically very diverse and had suffered innumerable plagues and pestilences by the time Columbus left these shores, so what was left of the population (after a very high rate of perinatal and infant deaths) was fairly resistant and understood some methods of quarantine and treatment for the diseases they exported. But they didn't export the treatment.

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Physiology & Medicine / Re: The crucial ingredients of CBD:

« on: 23/06/2022 22:42:06 »

You can probably hang the soft bits that everybody remembers, on a secondhand skeleton, thus eliminating most of the requirement for calcium and phosphorus. The other stuff is only required to make it all function, but to misquote a famous authority, a dead mouse is a perfect model of a live mouse, if only for a short period.

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Physiology & Medicine / Re: Why where the native Americans so vulnerable to disease?

« on: 22/06/2022 17:26:38 »

Relatively small gene pool, isolated for maybe 10,000 years, never acquired residual herd immunity (people often forget the word "residual" - you may have to kill 90% of the population to achieve it!), many deliberately infected in the later stages of colonisation, deprived of agricultural land and clean water, negligible provision of health services....you name it. 

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That CAN'T be true! / Re: Are home water filtration systems a waste of money?

« on: 15/06/2022 11:03:12 »

Worth remembering that when the US food & drug administration tested practically every available brand of bottled water about 30 years back, they found New York public mains water to have the lowest level of pathogens and contaminants.

Also worth noting that the BBC ran an open-label tasting competition between various bottled waters. The highest score from every taster was given to a product whose label said it was spring water from an uninhabited  Pacific island over 1000 miles from any source of industrial pollutant. All the bottles actually contained chilled London tap water.

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That CAN'T be true! / Re: can deuterium depleted water improve health?

« on: 14/06/2022 18:08:13 »

It's a good way of getting rid of the waste product after you have extracted the valuable deuterium from tap water.

Much the same as corn flakes, made from the waste after extracting syrup, glue, and a dozen other valuable products from maize. Apparently the sludge is so useless and indigestible that they have to add sugar, salt, vitamins and minerals in order to sell it as a food.

As for Marmite.....but at least it tastes good.

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Physics, Astronomy & Cosmology / Re: What are the properties of space?

« on: 14/06/2022 13:41:06 »

Maybe there are some important dynamic fields in the universe and the frequency of radiation emitted by Caesium-133 atoms is changing as a result of that, so that the atomic clocks used to define the second are not actually keeping the correct time.

If said fields are homogeneous, then we'll never know because everything is coming and going at the same time. Except that the light received from an object umpteen light years away will have a different frequency from what we have calculated, and whatever determines the field vectors must have some supraluminal means of directing them.

And if the fields are not homogeneous, then we can blame GPS navigation errors  on something we can't sense or predict, i.e. local wobbles in the Eternalstudent field. But so far, no evidence - I get the blame every time for not updating the database.

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Just Chat! / Re: how can intelligent people be trump supporters?

« on: 13/06/2022 16:22:19 »

an inveterate liar, a narcissist, a positive danger to democracy and an utterly selfish man

Rather like our present prime minister. Or indeed almost every member of his government, some of whom are also stupid. Or Mr Putin.

Fact is that a successful politician is someone who had no friends at school, for reasons that become obvious in later life. Children can smell it.

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Physics, Astronomy & Cosmology / Re: What are the properties of space?

« on: 12/06/2022 00:45:04 »

I would argue that G is a property as it tells us the degree of warping a given mass will produce

But doesn't that make it a property of mass rather than spacetime?

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Physics, Astronomy & Cosmology / Re: What are the properties of space?

« on: 10/06/2022 13:00:59 »

Current consensus is that the big bang produced a lot of stuff dispersed in space, and gravitation gradually makes it coalesce into lumps, so the observed separation is temporary. Except that some stuff seems to be receding at an ever-increasing rate, presumably into more space.

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Physics, Astronomy & Cosmology / Re: What are the properties of space?

« on: 10/06/2022 00:06:38 »

Space is what separates bodies of stuff. Not sure about "properties" beyond μ and ε, but we can certainly describe the static (fields) and dynamic (particles and waves) contents of regions of space. So if you want to be philosophical you could describe the ability to contain such phenomena  as a property of space, but I suspect this is a sterile  intellectual cul-de-sac.

Is G a property of space? I think not.  g is an observable property of stuff, and you could argue that G is merely a constant of proportionality that relates the observable g to m and r, because if you interpose a third body of any length between your two experimental masses it doesn't alter the original gravitational attraction by filling space, but adds to it by virtue of its own mass.

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Physics, Astronomy & Cosmology / Re: Is there a net heat exchange between water and ice at 0 degree C?

« on: 08/06/2022 18:01:01 »

The average of n samples of x is ( x_i)/n. At least it was when I was alive, but this thread seems to be some kind of scientific purgatory.

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Just Chat! / Re: Titles

« on: 04/06/2022 22:41:47 »

I guess if I had a life, I wouldn't be posting here. So maybe the top rank should be "living dead".

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Plant Sciences, Zoology & Evolution / Re: Why Are There No Freshwater Cephalopods?

« on: 29/05/2022 15:17:14 »

Same reason there are no oceanic apes, I guess.Each to his own ecological niche!

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Physiology & Medicine / Re: Can You Define What a Woman Is ?

« on: 28/05/2022 18:01:20 »

Just stick with the XX chromosomes. The reproductive bits don't always work and are sometimes removed if they go very wrong, but every cell of a woman's body contains two X chromosomes and every adult member of homo sapiens with two X chromosomes is a woman.

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Physiology & Medicine / Re: Does reasoning like humans exist in one species only ?

« on: 28/05/2022 17:54:23 »

I was wondering, should circumstances had prevailed, of the possibility that a dinosaur (or other species) would have evolved along the same speed and scale as humans.

They did far better. On the one hand they produced such a successful variant that the crocodile probably hasn't changed its design or its habits in 200,000,000 years, whilst  in a completely original direction they evolved feathers, hollow bones and a high temperature metabolism so they could fly.

After some 100,000 years, humans have merely invented more methods and more stupid reasons for killing other humans who present no actual threat.

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Physiology & Medicine / Re: Does reasoning like humans exist in one species only ?

« on: 28/05/2022 17:48:29 »

Many years ago I watched a gorilla in Chessington Zoo perform Galileo's demonstration of universal gravitation.

He had two apples, one larger than the other. He dropped them both and noted that they hit the ground at the same time. He then repeated the experiment twice: once exactly as before, then with changed hands.That is the whole process of experimental science: observe, hypothesise, repeat, alter one parameter at a time to test the hypothesis.

Humans being singularly (probably uniquely) superstitious and gullible, the Church persecuted Galileo, but the other gorillas, being of superior intellect, accepted the result and the experimenter ate the apples in peace.

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Physiology & Medicine / Re: Can JUST a head survive ?

« on: 27/05/2022 19:57:00 »

No obvious reason why not, but whilst an elementary textbook might show any organ merely devouring glucose  and oxygen (science), the details of the plumbing and chemistry are very complicated (engineering - or biology, if you prefer).

Old Irish story: Traveller arrives in Dublin and asks the way to Cork. Bloke says "If I was going to Cork, I wouldn't start from Dublin". So here's the sales engineer's response:

The simplest and cheapest way of keeping a head alive is to leave it attached to the original body, which can process common foods and ambient air into whatever the brain needs. Our standard product runs on fish, chips and mushy peas, washed down with beer. Runs for about 80 years with minimum maintenance, and if you get a complementary pair, they will make another one - complete with head - automatically.

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Question of the Week / Re: QotW - 22.05.23 - Where does the potential energy of a spring go in acid?

« on: 23/05/2022 18:32:18 »

My father was asked the same question in the 1940s - it's a real classic.

Fortunately James Joule answered it on his honeymoon when he measured the mechanical equivalent of heat, 4.2 joules per calorie. If you dissolve two identical springs, one compressed, and measure the heat of reaction, one will release a bit more energy. 

19

Just Chat! / Re: a suitable pseudonym

« on: 21/05/2022 22:31:23 »

You can safely assume that many scientists are borderline Autistic

How safe is that assumption? I've never met a scientist who I would call remotely autisitic. Progress in science depends on absorbing ideas from others, communicating your own findings, engaging in discussion and review, and lots of teamwork. Don't confuse the ability to focus and analyse, and the possession of a healthy contempt for consensus and imprecision, with autism.

Apropos the question in hand, unless your  name is John Smith, I can see no reason to adopt a pseudonym. The handle your parents gave you should be enough to identify most people in a small forum.

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Chemistry / Re: How well understood is the Chemistry of the trans-uranic elements?

« on: 17/05/2022 17:17:16 »

Up to about element 98 they are sufficiently stable for "ordinary" laboratory chemistry, with plutonium (94) and americium (95) actually having industrial applications.