Tell Me Something I Don't Know

Discussion in 'General Science & Technology' started by sharetolearn, May 4, 2009.

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  1. Oli Heute der Enteteich... Registered Senior Member

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    I've read since I was four years old, in all sorts of light (including the street lamp across the road when young and told to turn off the bedroom light).
    I still read better without glasses than I do with.
    (53 y.o.)
     
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  3. madanthonywayne Morning in America Staff Member

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    That means you're near sighted. What is lost in the forties is the ability to change focus. Can you legally drive without glasses?
     
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  5. Oli Heute der Enteteich... Registered Senior Member

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    Nope, glasses or a single contact.
     
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  7. ElectricFetus Sanity going, going, gone Valued Senior Member

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    No I'm talking about state of the art ones like Crystalens which can be focus like a natural eye lens, not Yet approved in the US but in Europe, >80% of patients no longer need glasses.
     
  8. madanthonywayne Morning in America Staff Member

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    Actually, the bifocal IOL's are state of the art. Crystalens has been around longer than the latest bifocal IOL's and the results with bifocal IOL's far surpass the results with "accomodating" IOL's. Certainly, the idea of an IOL that actually accommodates like the natural lens pre-age forty would be a great thing. But we have a way to go before we perfect that. The crystalens only provides about 1.50 diopters of accommodation, which is insufficient for many tasks. Which is why, right now, the bifocal IOL's are more popular than the accommodating lens.
     
  9. jmpet Valued Senior Member

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    A human head decapitated properly can continue to see for up to 30 seconds after decapitation.
     
  10. jmpet Valued Senior Member

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    I intend to plan the perfect murder.

    Of course, my posting it here ruins the plan...
     
  11. ElectricFetus Sanity going, going, gone Valued Senior Member

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    Your bases is on present technology while I'm speaking of technological direction and projected performance, a non-accommodating lens will forever be inferior to a natural lens, the only hope of replicating or surpassing the capabilities of a natural lens is to be accommodating. True, accommodating lenses of today are still limited in performance, but they won't be for long.
     
  12. Exterminate!!! Registered Member

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    lucky i didn't make the same mistake.

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  13. Pandaemoni Valued Senior Member

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    The air immediately around a lightning strike is routinely heated to temperatures hotter than the surface of the Sun (between 18,000º and 50,000º F for lightning and a mere 9,980º F for the surface of the Sun).
     
  14. Xylene Valued Senior Member

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    Not true--I'm 56 and I still don't need glasses yet. (touch wood

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  15. Xylene Valued Senior Member

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    During the enormous artillery barrages in both World Wars, the artillerymen used to yell as loud as they could to equalise the pressure on their eardrums, so they wouldn't go deaf. I daresay it didn't work for most of them.
     
  16. draqon Banned Banned

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    you are deaf?
     
  17. Diode-Man Awesome User Title Registered Senior Member

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    Sciforums.com is superior to sharetolearn.net


    ;-)
     
  18. Orleander OH JOY!!!! Valued Senior Member

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    and how do they know that? It might be able to blink, but how do they know its seeing?
     
  19. Fraggle Rocker Staff Member

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    It's not an extraordinary assertion so it's not subject to automatic challenge under the Rule of Laplace. The organs in the head are connected directly to the brain through very short, direct connections that are not bundled in the spinal cord like everything in our torso. This includes both sensory nerves for vision, hearing, smell and taste, as well as motor nerves for blinking, moving the eyeballs and mouth, and the sense of touch and kinesthetic feedback on the face and in the mouth.

    As people suffer from progressive nerve degeneration, usually the last things to go are sight and hearing, and they can still communicate by blinking.

    If a person whose torso has been cut off can still blink, that's evidence that he's still conscious (by no means a guaranteed condition after such a massive shock to his system) so it's extremely likely that he can still see and hear.

    Medieval battlefield lore (for what it's worth several centuries later) is full of accounts of severed heads also trying to talk.
     
  20. Orleander OH JOY!!!! Valued Senior Member

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    How do they know the blinking is on purpose. I blink all the time and I'm not aware of it. Its just what my body does. Now, if the head winked, that something different.

    How often has this been recorded?
     
  21. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    I greatly doubt that consciousness survives even one second after decapitation for the reason you sort of hint at. (Part of your text I made bold.) There should be expected a lot of spasmodic contractions of head mussels, including tongue and mouth related ones, but this need not indicate any conscious control.*

    I would be willing to bet that an EEG would immediately show increased amplitude but still be with the typical noise like activity in the sensory cortex but in a few seconds, at most, most of the brain would developed a more synchronous activity somewhat like the "kindling" of an elliptic seizure.

    Note that in epileptics consciousness is always lost in a second or so if the synchronous firing of spreads to the entire brain. The large amplitude synchronized activity can remain focal and if it does so, it is called "Jacksonian epilepsy." This can sometime be cured by surgery and often is associated with some local trauma, like knife wound or metal fragment but many cases are idiopathic also.

    Also, extreme pain will cause loss of consciousness. Have you ever seen a film of a zebra being killed by a pride of lionesses? It struggles violently then suddenly ceases all resistance, as it is no longer conscious of anything. This also makes me doubt assertions that the decapitated human remains conscious.

    I have worked with Rhesus monkeys and recorded their seizures. (Epilepsy does not natural occur in them, but can be induced by placing some alumina? dust** on the cortex.) In sort of an act of bravado, I would sometimes stand with my back to the monkey in the restraining chair and watch the EEG being written and verbally describe to a colleague watching the monkey which parts he was shaking etc.*** (We tried to make only Jacksonian Epilepsy with small focus in the motor cortex so that hired girls could watch dozens of individual cages and produce records of when and for how long the seizures lasted. (Project related to test of implanted cerebellar electrical stimulation as a cure for epilepsy and only about 15% of the monkeys became "regular" enough in their seizure patterns. The most regular ones were then implanted with a stimulator in hope that we could tell if it was making any difference. It did not seem to, but our sample was too small to be sure. A doctor Cooper in Boston area was putting similar stimulators into humans with nothing but his ideas to support this procedure - no animal testing first!)

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    *You may not know but a cat which has just had its cortex brain sucked out can walk.**** You only need to to establish the patterned movements and they will continue for quite a few steps. Many farmers will confirm that they have chopped the head off a chicken not quite correctly so part of the brain stem remains attached to the body and it will run around in the yard. Point is that patterned movements do NOT indicate consciousness. There is even the story a pirate (Blue beard?) was allowed to run past a shoulder-to-shoulder line of his crew as his head was lopped off. Every man he ran by after that would be spared - and that he saved several (4 or 5) by headlessly running past them.

    **I am no longer sure of the exact compound, but it is also used as an anti-acid by humans with stomach problems.

    ***Our EEGs were cleaner than normal (free of scalp artifacts) as we had Dura contacting metal tip electrodes in small "bur holes" with insulated wires to a skull mount DIP socket used as a connector. (Monkeys are amazingly resistant to infections as this DIP socket was a permanent hole in their scalp and never was any problem, but the skin did go over the dental acrylic "glue" around it. The entire assembly was made by spot welding at APL - It had 8 "legs" of different lengths so was called a "spider.")

    ****Even around an obstacle instead of into it, I think. In lesser than human mammals, an increasing fraction of the retinal signals do not go to the visual cortex. I know that some monkeys with all of V1 removed can still pick up a peanut from the floor and eat it. Even in humans, that are "cortically blind" (visual cortex destroyed by stroke or removed) have "blind sight" (search on that term for more). I.e. if told to reach out and take object from your hand or other location they know, they will shape their hand for grasping it correctly BEFORE ANY CONTACT with the object. For example, picking up tennis ball vs a cup or pencil.
     
    Last edited by a moderator: May 18, 2009
  22. sharetolearn Registered Member

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    That doesn't surprise me, vocalizing to protect yourself from loud noises is pretty smart, check this out: sharetolearn.net/171
     
  23. Xylene Valued Senior Member

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    What's more, a human head which has been decapitated below the larynx (so that the voicebox is intact) can continue speaking for a few seconds before brain activity ceases due to blood loss.
     
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