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NYarvin's profile
Norman Yarvin
Norman Yarvin
Norman Yarvin
@NYarvin

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Norman Yarvin

@NYarvin

yarchive.net/blog
Joined April 2013

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    1. Ben Turner‏ @BT_BXL 29 Jul 2019
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      Replying to @gcochran99

      I would reverse this and say if running is your best evidence for important differences between populations then it is not that impressive. In the last Olympic marathon final the Kenyan winner finished less than 2 seconds ahead of Galen Rupp of the US in third. Is that it?

      13 replies 1 retweet 9 likes
    2. Gregory Cochran‏ @gcochran99 23 Sep 2019
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      Replying to @BT_BXL

      The evidence for genetic differences in running ability is only as strong as a bear - say, a fully mature male grizzly that's been well fed, been working out, and has been sneaking both steroids _and_ inhuman growth hormone on the side.

      1 reply 4 retweets 14 likes
    3. Gregory Cochran‏ @gcochran99 23 Sep 2019
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      Replying to @gcochran99 @BT_BXL

      As such, it serves as a reliable detector - anyone arguing against this is really, truly nuts.

      1 reply 3 retweets 14 likes
    4. Ben Turner‏ @BT_BXL 23 Sep 2019
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      Replying to @gcochran99

      Cute that you still thinking about this since July. (Note to GC’s slower followers: read the thread, learn about the ethnic composition of e.g. Kenya, think whether difference in one trait is really evidence for differences in all traits. We know you don’t care about running).

      3 replies 0 retweets 1 like
    5. Gregory Cochran‏ @gcochran99 23 Sep 2019
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      Replying to @BT_BXL

      A significant difference in one trait - like height, or running speed - is an existence proof that selection could have driven significant differences in any other trait - not that there necessarily is. Which is why people like you resist the obvious.

      3 replies 5 retweets 37 likes
    6. Ben Turner‏ @BT_BXL 23 Sep 2019
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      Replying to @gcochran99

      It is suggestive to the suggestible. But this is an empirical question so why not wait for the evidence instead of making your mind up based on this? (Don’t worry you don’t need to answer that, we know why.)

      1 reply 0 retweets 0 likes
    7. Gregory Cochran‏ @gcochran99 23 Sep 2019
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      Replying to @BT_BXL

      Why not wait for the genetic evidence, rather than rashly assuming that Thoroughbreds are faster than Shetland ponies?

      4 replies 3 retweets 28 likes
    8. Gregory Cochran‏ @gcochran99 23 Sep 2019
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      Replying to @gcochran99 @BT_BXL

      East Africans have skinny legs: skinny legs are what you want for long-distance running, because fatter calves result in a bigger moment of inertia. Shall I explain moment of inertia? And so on: we know a lot about the mechanics and physiology of running.

      6 replies 4 retweets 16 likes
    9. Gregory Cochran‏ @gcochran99 25 Sep 2019
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      Replying to @gcochran99 @JayMan471 @BT_BXL

      Thinking about it, what fraction of adult Americans understand torque and moments of inertia? 5%? 2%?

      2 replies 1 retweet 7 likes
    10. Gregory Cochran‏ @gcochran99 25 Sep 2019
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      Replying to @gcochran99 @JayMan471 @BT_BXL

      One could go on to ask what fraction understand quantitative inheritance - < 1%, probably. How many people know that nuclear reactors are practical because of delayed emission?

      2 replies 1 retweet 7 likes
      Norman Yarvin‏ @NYarvin 26 Sep 2019
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      Replying to @gcochran99 @JayMan471 @BT_BXL

      Ah, delayed emission helps, but it's not essential. Thermal neutrons have a higher fission cross-section than fast neutrons and are physically slower, which slows the process down a lot. U238 doppler broadening also helps: instant negative feedback.

      12:32 AM - 26 Sep 2019
      0 replies 0 retweets 0 likes

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