1

Physiology & Medicine / Re: Why do finger tip pads heal so well?

« on: 28/12/2021 18:28:53 »

if someone loses a slice of tip above the nail there is a good chance it will grow back

It did.
In fact I can't even see or remember which finger it was now, after all these years.

I've had a little damage to the tips of a couple of nail beds over the years. 

One, I touched the tip of the finger with a bandsaw about 30 years ago. 

It did heal, but I think I ended up with a little scar tissue under the nail, and it has never been quite perfect.  A slightly weaker nail, or a good place to get slivers or pieces of grass under the nail.

2

Physiology & Medicine / Re: Why do finger tip pads heal so well?

« on: 28/12/2021 00:13:45 »

One would note that hand palms, and foot soles have what is called "thick skin" which is different from the rest of your skin.

However, I agree with @Kryptid that there is a strong evolutionary advantage of tough skin on the palms and soles, and rapidly healing.  Note that animals such as cats and dogs also have "pads" on their feet which are quite tough, but they'll occasionally get it cut and it will heal.

3

COVID-19 / Re: Getting covid booster whilst sharing house with a positive case

« on: 28/12/2021 00:06:03 »

A little late now, but testing isn't bad.  Then I'd go ahead and get the booster.  Hopefully at a drive-through clinic or similar that would have minimal exposure for others who are more vulnerable.

There are some diseases like Rabies that can be effectively vaccinated during the latency period.

COVID isn't quite the same, but it wouldn't hurt to wake up the immune system shortly before the disease hit.

4

COVID-19 / Re: COVID: what does the future will look like?

« on: 28/12/2021 00:00:28 »

With nearly 8 Billion possible human hosts, a virus won't care how lethal it is.

Smallpox didn't care how lethal it was.  Nor has AIDS/HIV. 

The biggest factor will be human behavior based on perceived risk.

I fully expect this to settle down somewhat like the flu, with most of the global population either having been vaccinated and boosted, and boosted again, or having gotten the disease, perhaps multiple times.  Either way there will be a certain amount of immunity built up which will reduce the severity of the disease. 

I do think we are beginning to see some society immunity effects that are protecting from Omicron. 

However, I also like the theory that Omicron evolved in one or several HIV/AIDS patients, and evolved to be less lethal (don't kill the already diseased host), while picking up several mutations to become more infectious. 

Also, while there were a lot of Delta infections at the time, a non-Delta variant may have spread easier in the population that already had high levels of Delta infections.

Like the flu, we may end up with several dominant strains in the future.  I still expect this to become seasonal, jumping from the Northern to the Southern hemisphere and back every year.

5

Technology / Re: Do operating system updates require new computers?

« on: 27/12/2021 21:54:59 »

Over the years I've had numerous computer upgrades, from 64kb of memory to 640kb of memory to a couple of MB, and on down the line. 

I am currently running with 8GB of RAM, and my browsing doesn't like it one bit. 

While a single upgrade might remain moderately stable, time will bring more upgrades, more powerful programs, etc, and more hardware upgrades.

One thing I've started looking more and more at are SSDs.  Some are mighty speedy, and would help significantly with both booting, and data swapping.

6

Technology / Re: Would minirockets have any military value?

« on: 27/12/2021 21:48:07 »

Our modern ammunition was largely developed about 150 years ago, around the time of the US Civil War. 

The advantages of cartridge and clip/magazine load became very obvious when a soldier could shoot a half a dozen shots, reload in moments, and fire another half dozen shots, all the while the enemy could fire a single poorly targeted musket shot.

I think there were some paper cartridges developed from time to time.  But, the modern brass cartridges are dependable, moderately water and humidity resistant, and can be handled fairly roughly as long as you are careful with the primer.

Most hand held "modern" guns are also recoil loaded, although there are some high speed automatic guns that are power operated (similar to the vintage Gatling Guns).

I could imagine building a reverse shell leaving only the primer behind, but that would mean a larger, and probably less aerodynamic bullet.

And, of course, with explosive acceleration, a bullet can achieve greater than the speed of sound before leaving the barrel of the gun.

Now, that doesn't mean there isn't a niche for some kind of a rocket propelled bullet.  There is a growing market for "Smart Ammunition".  In particular with person to person combat.  The ability to shoot around obstacles, or at something that isn't within the line of sight.

And, of course, sniper technology is mighty extraordinary.  A long shot of say 2 miles might take nearly 10 seconds of flight time, with the bullet at the mercy of wind direction, wind speed, etc.  Using the general gravity acceleration, , the bullet is falling quite far.  Having the ability to do precision targeting would be a huge benefit.

7

That CAN'T be true! / Re: New Theory: How did pebbles form?

« on: 17/08/2021 04:57:44 »

Clay is sediment and most surface rocks are too.

I'm not sure if that would be true. 

There certainly are sedimentary rocks.  But, there are tons of different types of rocks including granite, metamorphic rocks, igneous rocks, etc.  What is most common in any one location would depend on the geologic region, and the forces that created the surface features.

In many cases sedimentary rock crumbles easily.  Lava can be porous.  Granite can be some of the hardest rock, great to be crushed into small pieces, then tumbled in rivers to make pebbles.

8

General Science / Re: Shouldn't we worry about Earth before we try to conquer Mars?

« on: 15/08/2021 08:01:38 »

I agree that we have to take care of our own planet. 

A Moon colony could be extremely helpful as a stepping stone for space exploration.  Also one could have some extraordinary lunar based telescopes. 

A Mars (or Venus) colony would be more for curiosity, or a challenge.  It could prove whether we could ever move out of the solar system.  And, would be a backup for a catastrophic event on Earth.

However, don't expect a thriving Earth/Mars tourist business, or exporting say a billion people from Earth to Mars.  It is likely that travel between Earth and Mars will forever remain expensive and arduous, and may well be limited to a few hundred, or a few thousand people ever making the trip. 

A Martian colony would have to eventually become self supporting.

9

Question of the Week / Re: QotW - 21.08.15 - How much of the brain is memory?

« on: 15/08/2021 06:18:23 »

I'm looking forward to hearing the TNS answer.

I'm with @evan_au, I think a large portion of the brain is used for memories. 

While there is some specialization of different parts of the brain, there is no "Grandmother Cell", with general distribution of memories.  And some plasticity of the brain to recover from damage.

https://qbi.uq.edu.au/brain-basics/memory/where-are-memories-stored

10

General Science / Re: How can some planes can fly higher than others?

« on: 15/08/2021 05:30:48 »

One should also note the benefits of high altitude flying.  In particular, the lower air density would give less drag, and allow higher velocities and less fuel consumption.

Jet Streams?

For sustained flight above 10,000 ft, supplementary oxygen is mandatory (for the pilot, not  the engine) and this adds weight.

I presume that is either supplementary oxygen, or a pressurized fuselage. 

11

Plant Sciences, Zoology & Evolution / Re: Where Are All The Interbred Birds ?

« on: 15/08/2021 05:09:11 »

Hmmm...  "Bird" is awfully broad. 

Looking at Canadian Honkers on Wikipedia:

Kingdom:    Animalia
Phylum:    Chordata
Class:    Aves
Order:    Anseriformes
Family:    Anatidae
Genus:    Branta
Species:    Branta canadensis
Binomial name: Branta canadensis

So, if one pushes up the evolutionary tree to "Genus: Branta", they will interbreed some.  I've seen domestic white geese that have mixed with wild Canadian geese.

Geese and Swans are apparently close enough that they will periodically hybridize.

Looking at chickens:
Kingdom:    Animalia
Phylum:    Chordata
Class:    Aves
Order:    Galliformes
Family:    Phasianidae
Genus:    Gallus
Species:    Gallus gallus
Subspecies:    Gallus gallus domesticus
Trinomial name: Gallus gallus domesticus

Any "chicken" within the Species Gallus gallus would be able to interbreed. 

I have to wonder if even though many birds are migratory, different subspecies will be geographically isolated, but could potentially interbreed if the came into contact with distant cousins. 

Wild and domestic turkeys will also interbreed.

Perhaps one of the more distantly related hybrids is Guineafowl & Chicken hybrids.  Not all offspring are viable, and I believe they are all sterile.

12

The Environment / Re: Could we trap CO2 from car exhausts and use it as a building material?

« on: 01/07/2021 11:43:23 »

There must have been an awful lot of it around in the past!

But not all in the air at the same time.

What we know is that the Carbon Dioxide levels haven't been constant over time. 

I'm seeing notes that the CO₂ was as high as 8,000 PPM (or about 20x today's levels) 500 to 600 million years ago. But, it would have been even higher a few billion years ago before the "Great Oxidation Event". 

Stalactites and stalagmites are still forming indicating we continue to get calcium deposits.

13

Physiology & Medicine / Re: How are new viruses discovered?

« on: 01/07/2021 10:54:55 »

For diseases, one can look for a novel presentation of illnesses, or a particularly severe outbreak.  One problem is people who either don't see a physician, or each person goes to a different physician, so good community communication is important.

14

Physiology & Medicine / Re: Are there positive aspects to being fat?

« on: 01/07/2021 10:50:59 »

A lot will depend on how fat, how skinny, how muscular, etc for comparisons.  Fitness in general?

I  believe there is some benefit of having a slight "buffer".  So, if you get so sick that you can't eat for a week, then it is best not to start out with skin and bones.

On the other hand, if you are so obese that you can't move without a mobility scooter and you survive a plane crash in the middle of the Amazon Jungle, you may not fare well. 

Obesity can be hard on knee and foot joints. 

And, many people who are obese are also less active than their more slender brethren, thus more likely to develop cardiac and other problems.

As far as counting calories, those individuals who are more active also burn more calories, and thus don't have to worry as much about a snack or desert.

15

Physics, Astronomy & Cosmology / Re: How do astronauts deal with their waste?

« on: 24/06/2021 06:49:14 »

Hopefully for the International Space Station, they have a pack-it-in, pack-it-out policy, and not adding poop to space garbage.   

Ok, so here are some notes about the International Space Station.

Urine is recycle back to drinkable water.
Feces are loaded back onto transport vessels, and launched back towards Earth to  burn up on reentry. 

16

General Science / Re: How would I recognize the Adams Event?

« on: 15/06/2021 04:56:53 »

According to Wikipedia, the duration of a weak magnetic field lasted for about 700 years.

So, it wouldn't be something that one could simply sleep off in a cave.  And, one may or may not notice burning of the skin.  One would still have to go out for agriculture, hunting, and gathering.

However, it would likely be a generational thing.  If Gramps has really bad skin lesions.  Squamous Cell Carcinoma, Basal Cell Carcinoma, or perhaps Melanoma, that would be a good reason to go lather up with your SPF-10,000 sun lotion.

Could color of the skin also have become a selective trait for mates during that period?

17

Physics, Astronomy & Cosmology / Re: Does reflected sunlight have properties that could be harnessed?

« on: 14/06/2021 12:07:14 »

If objects didn't reflect light, they would be invisible.

Many objects will absorb some wavelengths, and reflect others, to create COLORS.

As mentioned above, mirrors have a special purpose reflecting light, and can used as telescope lenses.  Many old microscopes had a mirror to reflect light into the slide and lens.

Cats and many animals have a Tapetum Lucidum in the eyes which reflects light back through the retina, thus doubling the light on the receptors, and the reason animal eyes are often so eerily bright at night.

18

Geology, Palaeontology & Archaeology / Re: Are there mountains/mountain ranges that existed, but no longer do?

« on: 13/06/2021 18:02:40 »

It might take some hunting, but inevitably at least some of the large asteroid impact events have completely destroyed hills or mountains.

It might be hard to discern what was under the impact crater unless it hit the middle of a mountain range.

According to this article, the Chicxulub impact may have momentarily pushed up a mountain higher than Mt Everest, but it rapidly collapsed back down as part of the event.

The Vredefort crater is about 2 billion years old, and largely eroded away.  Core samples may show characteristic layers of earth displaced by the impact.

Other large craters (and domes/rings) may be even more difficult to discern.

19

Geology, Palaeontology & Archaeology / Re: Are there mountains/mountain ranges that existed, but no longer do?

« on: 13/06/2021 15:48:05 »

There are many volcanic mountains that have gotten shorter over the ages.

Mount Tambora was estimated to be 4,300 meters (14,100 ft) prior to 1816, and 2,850 metres (9,350 feet) after 1816.

Around here, Mount Mazama, as well as Mount Saint Helens have lost their tops.

There is some speculation that the Island of Santorini was Atlantis prior to an eruption leaving a sea level caldera, as well as devastating parts of the island that remained above water.



Although, it may have already been a caldera + cone prior to the most recent eruption.

20

Chemistry / Re: Where can I find magnesium metal scrap at home?

« on: 13/06/2021 15:10:56 »

Epson salt is MgS0₄

Of course not pure magnesium, but I wonder if it could be purified, either with high temperature electrolysis, or in a "battery".