Why birds can fly over Mount Everest (2020)
nautil.us
nautil.us
As any parrot owner knows, if you overheat a teflon pan, all the birds inside your house will die. So bird owners use stainless steel. There are other non-stick pans available, but it's really hard to wade through the marketing to figure out if overheating will kill the pet that's been in your family for years or even decades.
unrelated, the name of this article made me wonder if it was about thin air and lift, thinking how helicopters can't fly over everest.
But a mountain like everest might have a huge amount of updrafts to lift birds into the sky.
If you've ever stopped at an ridge overlook along california highway 1, you might see something curious. the ridges are bird-superhighways. the ocean air hits the cliffs and deflects upwards, and this updraft lets birds "surf" up and down the coast. So if you stand there and are patient, you'll see lines of gulls cruise by going north or south without flapping.
In the hang gliding world, ridge lift is a wonderful phenomenon that enables one to stay airborne almost indefinitely, with much better predictability than thermal soaring. The lift band is well defined by the incoming wind and upward deflection. When you’re done, just turn inland and exit the lift band.
We really should be taking steps towards a worldwide ban of this yet another asbestos-ass miracle material which sounds too good to be true because well, it is.
I don't get how that can even be allowed ad a regular household appliance.
This isn't to say that we shouldn't ban PFAS. They're proven to be dangerous to humans, and we should absolutely be concerned about long-term effects. It's just that "it kills a bird" isn't a justification for banning something. I'm under the impression that burned food and smoke isn't great for you either; it's possible that the trade-off between a dirty oven and increased PFAS exposure is acceptable.
Ultimately it depends on the magnitude of the danger, and I don't know enough about airborne PFAS to know if it warrants a blanket ban on any products with Teflon.
Few people know this, but the thing in chocolate that kills dogs, theobromine, acts as a caffeine-like stimulant in human beings but with a much longer half-life. Although human livers are much more able to deal with it than dogs, this could conceivably be causing human problems in people who often eat a lot of chocolate less than seven hours before bed.
[0] https://en.wikipedia.org/wiki/Xanthine [1] https://en.wikipedia.org/wiki/Theobromine
>I don't know enough about airborne PFAS to know if it warrants a blanket ban on any products with Teflon.
If you look at the CDC website, PFAS has a rap sheet a mile long. You should probably just clean your pans. If you can afford it, get a reverse osmosis system [3], they are very good at removing PFAS.
[2] https://www.atsdr.cdc.gov/pfas/health-effects/index.html [3] https://www.epa.gov/sciencematters/reducing-pfas-drinking-wa...
Well so will the actual caffeine.
Still, "not having the same effect on humans" is pretty misleading. It's maybe 4x more potent in a dog. Body weight is a much bigger factor. Not many people are going to eat "one ounce of milk chocolate per pound of body weight" or the equivalent dose of darker chocolate.
I am more or less immune to caffeine (in human concentrations), drinking all kind of coffees before going to bed (espresso, filtered, turkish, ...).
I noticed several times that it had the opposite effect (putting me to sleep). My brother has the same.
https://vcahospitals.com/know-your-pet/xylitol-toxicity-in-d...
I wonder about this. Is this a benign side effect, or the body's way of moving a troublesome substance out of the digestive system?
It seems there have been some investigations in humans, but to be honest the effects seem largely similar to a lot of other legal substances. Alcohol is dangerous to pregnant women and infants, a fatty burger can raise cholesterol, etc.
That is a cause for concern, and I've conceded this in my original comment. However, it's not the strongest evidence for a blanket ban.
Or, alternatively, we could treat this as strong enough evidence of an effect and ban many other substances that we use every single day. I can think of plenty of foods that raise cholesterol, and I can certainly think of plenty that pregnant women aren't allowed to eat because of low birth weight fears or other complications.
I don't know, it killing lots of things with lungs seems like a red flag to me.
Perhaps it warrants switching the assumption "Teflon good (until proved harmful)" to "Teflon bad (until proven safe)".
I will say that we should be wary of banning products based on potential long-term effects with unknown magnitude. Knowing where to draw that line is tough.
Or many household appliances that can reliably kill of your pets at all.
So I don't really get this nitpick.
Some things kill animals and not humans. Some quantities of substances kill animals and not humans. Knowing that a product kills your bird is cause for investigation or concern, but not a reason for a blanket ban.
In absolute quantities it's less toxic than fructose, paracetamol or THC. It's among least toxic substances found in nature. Almost no one dies from acute toxicity of alcohol - almost all alcohol-related deaths are due to accidents and chronic toxicity (long term exposure to toxicant).
it seems unlikely that they have both teflon coat it and a self-cleaning mode (800+F) that burns it off?
H2O is good; remove one atom, get explosive H2; add one atom get the bleach H2O2.
For chirality: S-penicillamine is an anti-arthritic, R-penicillamine is highly toxic[0] (I was going to use thalidomide as my example, but that turns out to be something which changes between both chiralities inside your own body).
Teflon is 100%, perfectly safe, as long as it never overheats. It is completely inert, causes no problems, can be eaten, etc.
As you say, when it overheats? It becomes toxic. I read some of the FDA docs referenced during approval, and it was along the lines of "As long as overheating does not occur".
They knew.
But then ran with the premise of "Citizens won't accidentally overheat their pan!". It really only takes a second! A pan on the stove, a distraction (kids, phone, a loud noise outside, whatever), a simple mistake, and BAM pan is overheated.
I'd say every teflon pan in use is toxic, essentially.
I don't know if the approval process has changed or not, but it seems like depending upon people to have 100% perfect adherence to pan heat levels is a bit much...
What other substances are approved this way? Frankly, I think any non-stick substance is suspicious, and use stainless steel.
The trick? Never use soap to wash it. Just use water, soak if needed, and if you can't get it all off? The next cooking will just be all the tastier. :P
Let the grease soak in, let the oils soak in, it does season a bit.
> BAM
You don't have to exaggerate that much.
> I'd say every teflon pan in use is toxic, essentially.
Do you find that oil in your pans keeps catching on fire?
Even if you do, a little bit of oil can give you a nice warning to prevent teflon-damaging levels of heat.
It takes very little time, just one little mistake, and that pan is now no longer inert teflon, but instead toxic teflon. Some have suggested that teflon should literally be banned, as a result of this.
Some even regularly cook at temperatures which are dangerous for teflon, eg > 600F, when searing a steak for example.
But I guess my whole point is, we 100% know it can become toxic. We also know that mistakes during cooking, or people not being aware, can cause this transformation. And it's a thing we put our food in, for crying out loud!
I don't think one can overstate how ... wrong it is, to use any non-stick coated pans. It's just not worth it.
whoops.
What bizarre logic.
It is an inert, non-organic reactive substance prior to being damaged. After, its molecular structure changes, it is bio-reactive and toxic.
So no, the solution isn't better ventilation, even for some of the questionable things you mentioned. And yes, you attitude before was "meh, gonna happen anyway".
True that not every helicopter can do it, but it can be done.
Would rotors with large surface area be how those helicopters work?
The life at the deepest points of the ocean also seem quite fragile.
Also, "canary in the coal mine". Canaries were sent into coal mines to detect carbon monoxide and other gases because they were more sensitive than humans. The bird would die before humans, giving an early warning.
How about the newer ceramic ones? I assume nothing will happen?
That being said, I have nitrided, stainless steel and cast iron cookware despite not owning a bird.
Carbon dioxide is the only substance for which we have such an alert. (Although there is another kind of alert for substances which smell bad. Most toxic substances don't smell bad.)
Assuming the humans are always in a ventilated area, though, nitrogen seems better along several dimensions.
Though, even with teflon gone from your kitchen, you've still got to be careful with other toxic fume sources such as overheated oil or the wax coating that most new pans come with :)
As for the pans: Just use them as you would any other pan and after a while you'll find them to be just as non-stick as any one of those overpriced poison pans. Don't bother with flaxseed oil as people on the internet like to recommend, soapy water is fine as long as you dry the pans well afterwards, and if you want to use metal cooking utensils in your metal pan don't let anyone stop you.
A specially built helicopter did land at the summit.
The Himalayas formed fifty millions years ago. Geese apparently appeared ten million years ago. How would this be possible?
> “The bar-heads have done that migration for millions of years before the Himalayas were as tall as they are now, and the birds have been pushed as the mountains have moved up to go higher and higher,” says coauthor Julia York, now a graduate student at the University of Texas at Austin, in an interview with the Times. York, who played foster parent to seven geese, adds, “They’re amazing athletes.”
https://www.the-scientist.com/news-opinion/bar-headed-geese-...
Your grandad is/was hom. sap. sap. but your (50,000,000 / 20)th grandad was one of quite a few possibilities, mostly ape and no sign of homo. I'm using a simple 20 year per generation model here. That's 2,500,000 generations ago. Here in the UK on telly, a comedian was shown how his (2021 - 1239) / 20 = 39 or so generational ancestor was English King Edward I - "longshanks". 39 generations gets you to 1230 or so, 2,500,000 generations is quite a long time ago.
So, let's look at these geese. 50M years back, the "dinosaurs" flying that route - let's call them "Goosey" - already had phenomenally efficient lungs compared to say mammals. As the land rose, they simply adapted a bit. Given how efficient their lungs are I doubt there was much to do.
It looks miraculous to us but we don't have those lungs. We didn't evolve the double ended lungs and hollow bones etc because we simply didn't need them or the cost of some part of that mix was detrimental for our use case or "we" simply rolled a double three. Evolution is weird. Well, no it isn't, that implies a blind watchmaker/intelligent design or nonsense as I prefer to call it.
In the words of a famous bloke: "Evolution is as evolution does". No more and no less. There are some geese that are able to fly over some mountains.
> 50M years back, the "dinosaurs" flying that route - let's call them "Goosey" - already had phenomenally efficient lungs compared to say mammals. As the land rose, they simply adapted a bit. Given how efficient their lungs are I doubt there was much to do. ... It looks miraculous to us but we don't have those lungs. We didn't evolve the double ended lungs and hollow bones etc because we simply didn't need them or the cost of some part of that mix was detrimental for our use case or "we" simply rolled a double three.
Are you saying that the Himalayas drove the development of birds world-wide? But despite that, we can only observe it in one species today? That makes even less sense to me.
http://www.lslbo.org/wp-content/uploads/2018/10/bird-lungs.j...
Note that sleeve piston engines like the Rolls Royce Crecy, are much more efficient than valves, but development stopped at the end of WW2 and resources focused on jet engines.
Rolls Royce Crecy - The Most Advanced Piston Aero Engine Never Made
https://www.youtube.com/watch?v=cxK_zWgw6gY
2) the exception to continuous flow is the WW2 V-1 pulsejet engine, which has a gate that is closed at combustion time, about 42 Hz.
The pulsejet is a very interesting engine in that it's the simplest possible jet engine - literally an empty metal tube with spray nozzles and a sparkplug.
The V-1 was the first mass-produced cruise missile. The Germans also had air-to-ground (anti-ship) guided missiles both wire-guided and radio-guided with a TV screen(!)
But the US Navy was the first to build precision-guided autonomous missiles, both the all-analog Sidewinder and Wall-eye, which shared modules. The Wall-eye made the famous Gulf War photos you've seen of entering via windows. It had analog circuitry to do edge-detection in real-time.
From my quick research just now, it seems continuous flow hearts are not better because they pump differently. That's just a side effect with no benefit that's noted in studies. A continuous pump is much smaller, and for long-term total heart replacement, is the only thing that can be small enough to fit in the body. In fact, it's noted in a case study that they're not sure about the long term effects of not having pulses, and that's something that will need to be studied.
Now as far as the lungs - I think that would be a bad idea too. We'd need separate flow-through pathways to inhale and exhale. So two necks, or an exit hole in the chest. That takes up space and is another vector for infection. In addition, exhaling moisturizes the tissue, so you'd need much harsher intake tubes, and your exhale tubes would be constantly dripping water. All that extra space has to come from somewhere - meaning you now have less space for actual oxygenating tissue, resulting in worse oxygen capture. Now the diaphragm has to pump harder, because you're not extracting as much oxygen from your air intake.
Anywise, you had a funny comment, which I hopefully made funnier by responding to it seriously. We're a good team. Team Heart & Lungs they call us.
He's on Twitter and a total medical/heart geek, I'm sure you could ask him and he'll probably provide you with references.
(Edited to add text in parenthesis in 3rd sentence)
Mammal: Inhale -> burn -> exhale
Bird: Inhale -> burn
-> inhale -> exhale
The bird mechanism is obviously efficient for oxygenation but it must have a cost that our body plan discarded or at least failed to even consider many millennia ago.
Our body plan didn't discard this mechanism, any more than it discarded wings or beans. We never had any of those features in our ancestry, because mammals aren't descended from birds. Our most recent common ancestor is much, much earlier than bird ancestors began evolving any mechanisms related to flight or high-altitude breathing.
You only climb mount improbable, you don’t go down it
Because their lungs are tied to their flight muscles, they would overbreath at cruising speed. So the long necks provide just the right amount of re-breathed CO2 to offset this.
(I hope I have this correct)
Granted, decaying lignin subtracts oxygen from the atmosphere, but had that happened alone the levels of oxygen would have gone down quite slowly. What we see instead is a drop from ~30% to 12% within a few hundreds of thousands of years. It means that a catastrophic event (such as prolonged supervolcanic eruptions) probably played a bigger role.
https://www.nature.com/scitable/knowledge/library/earth-s-ea...
Why Birds Can Fly over Mount Everest - https://news.ycombinator.com/item?id=23639294 - June 2020 (96 comments)
On that note, I'd welcome pointers to similar narratives that explain evolution, the formation of the planet, the universe etc.