public misconceptions

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p1t1o
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Re: public misconceptions

Postby p1t1o » Tue Mar 22, 2011 8:03 pm UTC

KingofMadCows wrote:Wouldn't it make more sense if Monet actually saw less yellow so he used more yellow to compensate for the deficit? It's like if you had a deficit in your ability to taste saltiness, you wouldn't put less salt in your food, you would put more. Similarly, if you were more sensitive to salty taste, you would put less salt in your food.


No, because he would not necessarily be aware of the deficit, he would still paint what he sees.

Unless someone was like "Yo, Monet, you need to yellow that shi* UP!" and he would be all "Dawg, it look weird, you crayzeh!"

If he compensated with paint then his painting would look different to his actual view, even to himself.

Fact is, apparently, that he had cataracts which do yellow your vision, so I don't think it was a brain thing at this point, it was just what the program was about.

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Re: public misconceptions

Postby Woofsie » Tue Mar 22, 2011 8:34 pm UTC

p1t1o wrote:
KingofMadCows wrote:Wouldn't it make more sense if Monet actually saw less yellow so he used more yellow to compensate for the deficit? It's like if you had a deficit in your ability to taste saltiness, you wouldn't put less salt in your food, you would put more. Similarly, if you were more sensitive to salty taste, you would put less salt in your food.


No, because he would not necessarily be aware of the deficit, he would still paint what he sees.

But if everything looked yellower, then his painting (with a normal amount of yellow) would also look yellower, so it would match up properly. Right?

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Kurushimi
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Re: public misconceptions

Postby Kurushimi » Tue Mar 22, 2011 8:46 pm UTC

No, think of it this way. Let's say the world usually has a yellow value of 50. Monet's condition causes him to see it as a yellow value of 40. When he paints, he wants it to look like the real world, so he makes it look like it has a yellow value of 40 TO HIM. But this is a yellow value of 50 to everyone els and, thus, also looks yellow.

Or in simpler terms, if he put more or less yellow than normal, he would be able to notice it just as much as we would.

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Re: public misconceptions

Postby p1t1o » Tue Mar 22, 2011 11:35 pm UTC

Oh dear, I was getting very confused with this. I was like "this doesn't seem to make sense, as long as his paintings match the world to him, they will to us as well, so how would we even know?".

But that doesn't match up with the fact that his colouring did drift as he aged.

I had a google around, this article seemed to make sense.

Rather than seeming to view the world through a filter, it was all colour definition that was deteriorating.

Not sure if this has anything to do with the brain's ability to compensate anymore, but interesting none the less.

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BlackSails
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Re: public misconceptions

Postby BlackSails » Wed Mar 23, 2011 1:31 am UTC

Yeah, that makes no sense to me.

He sees extra yellow. That means he sees extra yellow in the paint as well.

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Re: public misconceptions

Postby kernelpanic » Wed Mar 23, 2011 2:11 am UTC

I remember reading that he was able to see some near UV, and that somehow messed up with his paintings, because he had to use visible light dyes to represent something he saw in UV.
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Re: public misconceptions

Postby KingofMadCows » Wed Mar 23, 2011 2:32 am UTC

I suppose that it's possible that since Monet was such an expert artist that he didn't even look at the colors he used when he painted so he just automatically used colors that are more yellow. It's like how someone who's played the piano their whole life can still play even when they're deaf and blind.

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Re: public misconceptions

Postby p1t1o » Wed Mar 23, 2011 10:10 am UTC

Apparently as his sight deteriorated he had to label his paints as he had difficulty telling them apart.

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Re: public misconceptions

Postby Kurushimi » Wed Mar 23, 2011 10:33 am UTC

If his eyes were 'deteriorating', he may have wanted to brighten things up so that they looked like they used to look. Which would cause a discrepancy.

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Re: public misconceptions

Postby idobox » Wed Mar 23, 2011 11:36 am UTC

kernelpanic wrote:I remember reading that he was able to see some near UV, and that somehow messed up with his paintings, because he had to use visible light dyes to represent something he saw in UV.

That sounds pretty unlikely. Is there a documented condition where photophors happen to lie next to the retina, or of weird mutated pigments in the photoreceptors?
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Re: public misconceptions

Postby BlackSails » Wed Mar 23, 2011 1:41 pm UTC

idobox wrote:
kernelpanic wrote:I remember reading that he was able to see some near UV, and that somehow messed up with his paintings, because he had to use visible light dyes to represent something he saw in UV.

That sounds pretty unlikely. Is there a documented condition where photophors happen to lie next to the retina, or of weird mutated pigments in the photoreceptors?


Some people can see a little further in the UV than most, just through receptor mutations. Usually women afaik

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Re: public misconceptions

Postby p1t1o » Wed Mar 23, 2011 2:00 pm UTC

The human eye can respond, weakly, to x-rays under certain circumstances too. Mechanism is unknown, though conventional detection via the retinal pigments is possible.

What do you know, we all have X-ray vision! Not much of a superpower after all....

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Re: public misconceptions

Postby Mr_Rose » Wed Mar 23, 2011 4:17 pm UTC

Sounds like an interesting thing to test with all those backscatter x-ray machines they have these days.
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Re: public misconceptions

Postby Whelan » Wed Mar 23, 2011 4:52 pm UTC

I heard about a man who after laser eye surgery found himself able to see into the UV slightly. Some animals can do it, notably Peregrines I think, so it is biologically possible.
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Re: public misconceptions

Postby p1t1o » Wed Mar 23, 2011 4:59 pm UTC

Why would laser eye surgery reveal that?

For awesome eyesight (amongst other things - coolest animal ever!), google the mantis shrimp.

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Re: public misconceptions

Postby Whelan » Wed Mar 23, 2011 5:19 pm UTC

It's a half remembered anecdote. With a bit of googlingI've discovered he actually had his lens removed due to cataracts. The lens is opaque to UV, so when it was removed UV light was able to reach his retina, and the blue receptors could see it.

Also, replace peregrine in my last post with kestrel.
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Re: public misconceptions

Postby Meteorswarm » Thu Mar 24, 2011 7:17 am UTC

BlackSails wrote:Some people can see a little further in the UV than most, just through receptor mutations. Usually women afaik


You're thinking probably of tetrachromacy which is apparently unverified but possible in humans. Two of the three pigment genes lie on the X-chromosome, and if a woman has two different genes for one or more of them, then they will see in more colors than just the three we're used to, but the different versions are likely to be extremely similar.

This is also one theory on how primates came to have trichromatic vision in the first place (most mammals are bichromats) - a gene started to have variations, which diverged because they conferred an advantage, and ultimately drift and a lucky crossover put both on the same chromosome, and everybody walked away happy. Except those without the gene, I suppose.
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Re: public misconceptions

Postby idobox » Thu Mar 24, 2011 10:10 am UTC

Wow, I didn't know that kind of mutation existed.
For the x-ray part, I can see three explanations:
-The pigments are sensitive to x-rays.
-there are a bunch of things that will emit light when struck by x-rays
-x-rays are ionizing radiation, photosensors use a polarisation between the inside and the outside of the cell. X-rays triggering some mechanism to depolarise the cell would be simulate the action of light.
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Re: public misconceptions

Postby p1t1o » Thu Mar 24, 2011 10:22 am UTC

Yes, there are multiple possible mechanisms, but none have been verified as irradiating your head with intense x-rays is seen as a bit of a "no-no" for some reason....

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Re: public misconceptions

Postby idobox » Thu Mar 24, 2011 12:59 pm UTC

As a side note, it appears to be possible to detect fast neutrons and other particles with the naked eye by the cherenkov radiation they produce in the eyeball.
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Re: public misconceptions

Postby Yakk » Thu Mar 24, 2011 2:36 pm UTC

I have heard that seeing a "bright blue flash" when you are working with nuclear materials is a sign that you just got a serious dose of radiation (the blue flash being said cherenkov radiation inside your eyeballs).
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Re: public misconceptions

Postby p1t1o » Thu Mar 24, 2011 3:05 pm UTC

Apparently astronauts have reported that phenomenon, it can be seen when caused even by individual particles under certain circumstances.

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Re: public misconceptions

Postby Technical Ben » Thu Mar 24, 2011 3:44 pm UTC

idobox wrote:As a side note, it appears to be possible to detect fast neutrons and other particles with the naked eye by the cherenkov radiation they produce in the eyeball.

Is this the idea behind the flashes seen by astronauts? The report occasional flashes, thought to be caused by high speed particles from various sources such as supernova.
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Re: public misconceptions

Postby Mr_Rose » Thu Mar 24, 2011 4:06 pm UTC

Yakk wrote:I have heard that seeing a "bright blue flash" when you are working with nuclear materials is a sign that you just got a serious dose of radiation (the blue flash being said cherenkov radiation inside your eyeballs).

Pretty sure that individual flashes are, while diagnostic of a problem, not necessarily life threatening. It's when the air is glowing blue in front of you that you're basically already dead and just waiting for reality to catch up with you.
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Re: public misconceptions

Postby Headshrinker » Thu Mar 24, 2011 5:58 pm UTC


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Re: public misconceptions

Postby wtspman » Sat May 14, 2011 5:23 am UTC

Sockmonkey wrote:If any face cream actually had the ability to alter DNA we would see a whole lot of mutant fashion models which would be kind of awesome.


If your face cream was full of measles virus, it would definitely insert DNA into your chromosomes. But, alas you would not end up with a smoother complexion, unless of course you zoomed in really close on the resulting pock marks: at some scale of resolution it would have to be smooth.

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Re: public misconceptions

Postby Eebster the Great » Sun May 15, 2011 12:05 am UTC

wtspman wrote:
Sockmonkey wrote:If any face cream actually had the ability to alter DNA we would see a whole lot of mutant fashion models which would be kind of awesome.


If your face cream was full of measles virus, it would definitely insert DNA into your chromosomes. But, alas you would not end up with a smoother complexion, unless of course you zoomed in really close on the resulting pock marks: at some scale of resolution it would have to be smooth.

Why are you quoting something from fifteen pages ago?

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Re: public misconceptions

Postby mercutio_stencil » Wed Nov 09, 2011 8:46 pm UTC

I hate to bring back this thread from the grave, but I just ran into one of my all time least favorite misconceptions, depleted Uranium bullets. I really don't like having to give a small particle physics lecture to explain why they aren't radioactive. Granted, they aren't nice things, and they would suck to be shot with, but they don't turn battlefields into barren radioactive wastelands.

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Re: public misconceptions

Postby SlyReaper » Wed Nov 09, 2011 9:18 pm UTC

They are a bit radioactive. It's also a pretty nasty toxic metal, so there are still valid reasons to oppose its use.
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Re: public misconceptions

Postby p1t1o » Wed Nov 09, 2011 11:47 pm UTC

Fun fact: IIRC, tungsten rounds (the "safer" alternative) are more toxic/carcinogenic.

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Re: public misconceptions

Postby Eebster the Great » Thu Nov 10, 2011 3:48 am UTC

p1t1o wrote:Fun fact: IIRC, tungsten rounds (the "safer" alternative) are more toxic/carcinogenic.

This in vitro study is a bit old but suggests that DU is significantly more carcinogenic than weapons-grade tungsten alloys, though both could (probably) lead to tumor formation.

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Re: public misconceptions

Postby Shivahn » Thu Nov 10, 2011 6:34 am UTC

SlyReaper wrote:They are a bit radioactive. It's also a pretty nasty toxic metal, so there are still valid reasons to oppose its use.

That's true, but it's a far cry from what most people think of when they talk about how we're using radioactive ammunition.

The toxic metal part is a far bigger worry overall.

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Re: public misconceptions

Postby p1t1o » Thu Nov 10, 2011 10:00 am UTC

Eebster the Great wrote:
p1t1o wrote:Fun fact: IIRC, tungsten rounds (the "safer" alternative) are more toxic/carcinogenic.

This in vitro study is a bit old but suggests that DU is significantly more carcinogenic than weapons-grade tungsten alloys, though both could (probably) lead to tumor formation.


Here (full text) is a 2005 in vivo study that supports the toxicity of weapon-grade Nickel/Cobalt/Tungsten alloys routinely used to make ammunition. Admittedly it isn't the Tungsten that is proving that nasty, as I had originally thought, but WA penetrators are certainly not as benign as they seem.

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Re: public misconceptions

Postby Eebster the Great » Thu Nov 10, 2011 5:34 pm UTC

Well nickel is known to be extremely carcinogenic, so that's hardly surprising.

Also, that study never compares these metals to DU, so there's no way to say which is more dangerous.


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