1

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

« on: 24/06/2022 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.

2

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.

3

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. 

4

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

« on: 21/06/2022 17:36:21 »

I'm just waiting for the spam advertising.

5

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.

6

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.

7

General Science / Re: What takes more energy walking or skateboarding?

« on: 06/06/2022 22:34:27 »

Hi.

I agree with @chiralSPO,  more information is required.
    However, assuming no wind or air resistance, a perfect skateboard, perfect flat and level surface etc.     Then wheels are better (more efficient) than legs.   

    In principle a person on a skateboard could make the 100m distance without doing any work at all.    If the skateboard was already moving then it just continues as per Newton's Law  ("an object maintains a state of uniform motion unless acted on by a force").     Even if the skateboard was stationary to start with, the person only needs to put in enough work to make the skateboard have some kinetic energy and that's only temporary.  They can give it just a tiny amount of energy and that will be fine, it will eventually reach the end of the 100m journey with that same amount of kinetic energy.   If the person has a dynamo they can push against the skateboard wheels then they can recover that energy if they want at the end of the journey and keep it in a more useful form.
    Meanwhile, walking is an extremely wasteful process by comparison,  heat is produced in the persons muscles as chemical reactions happen,  muscle fibres and tendons get stretched and produce more heat, sound is released each time your foot slaps the floor,  the deformation of your shoes and of the ground each time your foot hits the floor also produces more heat.   Overall the person is required to do work and release heat into the environment every moment they are walking.   There is no realistic way to capture or recover all the energy that is being released into the environment.

Best Wishes.

8

Cells, Microbes & Viruses / Re: Monkeypox: Could it be similar to cowpox, and just a mild variant of smallpox?

« on: 28/05/2022 20:50:24 »

There seems to be an assumption that covid has gone away. It is still spreading and mutating. It's unlikely to return as a variant with increased pathogenicity and/or the ability to evade current vaccines but it is a possibility. It's early days in the evolution of a fast evolving virus.

9

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

« on: 28/05/2022 02:13:50 »

It's already been done, on Futurama... 

10

Physiology & Medicine / Can JUST a head survive ?

« on: 27/05/2022 18:32:28 »

Dear Cranial Inplantologists,

As a sheepy I just love my head being where it is. Each day I find it at the end of my neck and it pleases me no end.

Say I was the unfortunate casualty of a horrific happenstance ! A very serious papercut that separates my brain bowl from my body.
I know the outpour of grief would stop the Earth spinning but Could my head(or anybody else's head) remain alive and well if attached to the appropriate equipment


As a firm believer in empirical study I perchance found myself removing my neighbour's *head at 3am this morning and with the aid of Lego I created a toy car that I threw at it  !..A toy car that after all my endless research (none) I thought was the appropriate equipment...................anyway no luck there !....sheesh !!!


whajafink ?










*Please do not try this tat home, I am a trained neighbour-head remover.

11

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. 

12

Chemistry / Re: What colour is paint before the colour is added?

« on: 18/05/2022 18:32:01 »

It seems unlikely that the OP is going to return to a decade-old post.
Just in case they do- until you add the pigment, you don't have paint. So the question makes no sense.

13

Technology / Re: Which electric motor is best for electric bikes and scooters?

« on: 13/05/2022 23:29:17 »

metal bashers in the Midlands

How very 1960s! The Blessed Saint Margaret Thatcher deemed that Britain should become a service economy because her husband was an accountant, not an engineer. Rolls Royce and Mini are now subsidiaries of BMW, Jaguar is Indian, and practically every other British car manufacturer mysteriously became bankrupt after attracting massive re-flotation investment and cleaning out the pension fund.

There are still a few factories in Birmingham making sewing needles and belt buckles, and Coventry airport is planned to be the next entrepreneurial disaster, to replace the runway with a speculative megafactory to make Japanese-designed batteries for foreign-manufactured cars. Metalbashing on any significant scale is  now done in China, not the Midlands, because it is all about profitability.

14

COVID-19 / Re: Can covid tests also detect common colds?

« on: 13/05/2022 00:20:04 »

There are around 150-200 viruses that we classify as "the common cold". Only 4 of them are coronaviruses, so it's not really accurate to say "a cold is a Coronavirus".

You could produce a RAT test that detected one or a couple of the common cold viruses (eg adenoviruses), but it is unlikely that a single RAT test could detect all of them.

I am sure that one of the criteria for a successful COVID-19 RAT is that it did not react to the 4 "Common Cold" coronaviruses.

There are hints that people who have recently suffered from a "Common Cold" coronavirus are slightly protected from COVID-19, as their immune system responds to the family resemblance.
- This may be why children under 2 years old show some benefit from a COVID vaccine, while those 3-5 do not
- Children under 2 have lived during some form of lockdown, and may have had less exposure to the 4 "Common Cold" coronaviruses, and so may have less protection against COVID-19 than slightly older children.

https://en.wikipedia.org/wiki/Common_cold

15

General Science / Re: spherical implosions

« on: 03/05/2022 22:37:56 »

The Trinity test didn't need a perfectly spherical implosion - just good enough.
- And it worked - but they needed a much more compact arrangement if they were to fit it into a plane.
https://en.wikipedia.org/wiki/Trinity_(nuclear_test)

Another area trying to do spherical implosions today is the US National Ignition Facility, which is trying to initiate nuclear fusion with a spherically symmetrical arrangement of 192 lasers.
See: https://en.wikipedia.org/wiki/National_Ignition_Facility#Tests_and_construction_completion

16

General Science / Re: How to reduce cast iron melting point

« on: 01/05/2022 03:06:41 »

you get diamond powder

Carbon is very soluble in iron.
- Of the different allotropes (forms) of carbon, diamond is stable at high pressures (like > 150km beneath the surface of the Earth). At sea level pressures, graphite is more stable, so diamond is thermodynamically encouraged to slowly turn into graphite (although you can reduce the rate by cleaning it in hydrofluoric acid, with ties up a lot of the loose ends with fluorine atoms)
- One other allotrope is carbon nanotubes, and these have been formed by having tiny iron "seeds", which grow carbon nanotubes.
https://phys.org/news/2012-11-optimize-growth-individual-carbon-nanotubes.html

17

General Science / Re: How hot can two hairdryers make a charcoal foundry?

« on: 30/04/2022 16:48:51 »

Try a hot air gun paint stripper! The key to achieving high temperatures is mass, you will need a large volume to keep a large temperature. Insulation will not work as you have a problem with the fire needing oxygen.

18

Technology / Re: Are electric cars responsible for natural gas demand?

« on: 30/04/2022 12:29:39 »

I'm all for the electrification of transport. Underground railways and trolleybuses are great, and electric cars are terrific fun to drive.But we don't have (and can't have) enough electricity from non-fossil sources to abandon gasoline, diesel, and gas-generated electricity to meet current and predicted demand. 

And when the oil runs out, we won't have gasoline and diesel.
So we had better start planning to decarbonise the economy now, while we still can.

19

Technology / Re: Are electric cars responsible for natural gas demand?

« on: 25/04/2022 23:25:32 »

Renault issued press statements reaffirming their vehicles' compliance with all regulations and legislation for the markets in which they operate in 2015.

Note the careful wording. The entire "scandal" is a case of smart-arse legislators being caught by their own cleverness and complaining about it. If you prescribe a very specific acceptability test for a product with a wide range of possible performance, you have no right to complain if the product meets that specification but no other. Here's an old story that gets trotted out at purchaser specification meetings:

Man wants to make a new door frame. This usually consists of about  16 pieces of wood of specific thicknesses, cut to mitre angles. So our hero calculates what he wants and specifies each piece to  ± 0.05 mm and ± 0.05°. Hands specification sheet to a timber merchant who promises to have it ready in 24 hours. Next day he collects the bundle and is horrified to discover it is composed of bits of knotty pine, green ash, plywood, willow, and whatever else the good Lord chooses to call a tree, twisted, crossgrain, sawn, bodged..... Shop assistant produces a ruler, shows that each piece of crap is exactly the size and shape specified, and demands payment.

As he wonders how to complain, a woman walks in and presents a ticket. Assistant hands over a beautiful piece of polished seasoned oak, 8 x 24  x 1 inch, with radiused edges and a neat hole in each corner. Bloke says "what did she order?" Shop assistant says "a seat for her kids' swing".

The moral: tell the manufacturer what you want, not how clever you are.

20

Just Chat! / Re: why is bored chemist "bored"

« on: 14/04/2022 20:51:32 »

It's a very old name.
I first used it on a different site which was mainly about electronics.
They were arguing about some point of chemistry- I forget what- and I joined the forum just to be " a bored chemist surfing the net who came across this discussion", so I could explain that they were not getting anywhere in their discussion because the chemistry was fundamentally wrong.