Links for June 2015

  • Arrow bending.
  • Casting a fireant colony in molten aluminum:
  • The Crossrail tunnel boring machine in London.
  • The best introduction for laymen to the how and why particle physics experiments are built the way that they are: the Particle Adventure.
  • I have been saying for years that the mostly-positive metric is hands-down the better convention. Peter Woit gathers reasons.
  • Korea’s Team KAIST Wins the 2015 Darpa Robotics Challenge.
  • I share Noah Smith’s enthusiasm for experiments in economic policy. I subscribe to the philosophy that (perhaps charitably) models folks’ political biases as strong Bayesian priors. Whenever we have weak evidence, we are pulled to favor the hypothesis that leans strongest toward our biases while still being minimally compatible with the evidence. Although folks’ beliefs would track truth better if they could reduce bias, and I am pessimistic about this improving, we can still pull different sides together by compiling better evidence.

    There are uncountable fierce political battles that are usually considered intractably ideological, but which I have been convinced by others actually would yield considerably under the introduction of robust, unambiguous evidence. It’s darkly satisfying to think “my opponent ignores reason, so it doesn’t matter what evidence we collect; I’ll just have to beat him with rhetoric”, but this is a mistake largely grounded in a lack of appreciation for how weak the evidence we typically collect really is. Most of the vast resources we individuals put into pitched verbal battles would be better spent on ambitious controlled experiments, e.g., Robin Hanson’s call for larger scale version of the Oregon Medicaid and RAND health insurance experiments.

  • Airplanes use air taken directly from the engine to pressurize the cabin, known as bleed air.
  • There was some news about the recent solar sail experiment, but it is not true that this was the first. Ikaros was a precursor.
  • Have you ached for the ability to watch your cookies bake over a live webcam feed on your smart phone? Suffer no longer.
  • I imagine that volumes could be written about the signaling and game-theoretic aspects of Persian Taarof.
  • A popular-level introduction to the elemental abundances over the history of the universe.
  • I can’t comment about the accuracy of the author’s empirical claims about mentality except that they agree with my anecdotal experience, but this discussion of strategies for reducing the use of force by police is more constructive and sensible than most on this issue.
  • NYTimes write-up of recent research on genetic origins of Europeans.
  • Ballistic DNA injection — the use of gene guns to forcibly inject DNA into cells causing them later to express associated genes — lives up to its name:

    The earliest custom manufactured gene guns (fabricated by Nelson Allen) used a 22 caliber nail gun cartridge to propel an extruded polyethylene cylinder (bullet) down a 22 cal. Douglas barrel. A droplet of the tungsten powder and genetic material was placed on the bullet and shot down the barrel at a lexan “stopping” disk with a petri dish below. The bullet welded to the disk and the genetic information blasted into the sample in the dish with a doughnut effect (devastation in the middle, a ring of good transformation and little around the edge).

  • 7/8th of the land area on Earth is in one hemisphere.
  • Photos of the decaying remnants of the Soviet space shuttle.
  • Sting-operation chocolate “study” and crappy scientific journalism. Scott Alexander comments.
  • Enlightenment-era clock powered solely by minute temperature and pressure fluctuations in the environment. A single degree celsius fluctuations is enough to power it for two days.
  • New Horizons is approaching Pluto, and the new pictures are the best ever taken. The flyby will be July 14.
  • NASA mission to Europa is approved by first major review. (HN Commentary.)
  • I’ve very excited to hear more about Agora Fund, a charity evaluator in (very) roughly the same vein as GiveWell. They appear to strongly endorse impact evaluation, but cause neutrality less so. Poking around their website suggests they are a little more connected to the traditional philanthropic world, which could be great for allowing EA ideas to diffuse more broadly.
  • The top 10 mathematical achievements of the last 5ish years, maybe.” (H/t Sabine.)
  • Another fun demonstration of video processing algorithms.
  • Wooden combination lock. Impressive woodworking, plus a great illustration of how a combination lock works. (Bonus from the same guy: “This scaffold does not corner very well“.)
  • Megaprocessor: A microprocessor made of loose (non-integrated) transistors. Big.
  • Musk: “There was an overpressure event in the upper stage liquid oxygen tank. Data suggests counterintuitive cause. That’s all we can say with confidence right now. Will have more to say following a thorough fault tree analysis.” Video starts just before explosion:
    See also previously unreleased footage of the hard landings for the return of the first stage in earlier launches.
  • Interview with John Hunter, the guy behind Quicklaunch. Their website is defunct, but apparently the project is still going ahead. Today’s SpaceX failure notwithstanding, SpaceX will likely find a way to recover their first state before orbit is reached by a partially gun-launched object. This is something that is very surprising to me, a priori, which is an intuition that Hunter supports.
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  1. Bohannon may have been trying to fool people, but Alexander’s commentary indicates that chocolate may really be good for health. What’s your take?

    • I think the important point is just that the causal influence between scientific evidence and whats reported in the media is fully broken, with reports determined almost exclusively by what the journalism market selects for (click bait, etc.) I don’t care too much about individual dietary recommendations with regard to various foods because I think the true error bars on overall outcomes are so large, and the effects are so modest. Once you avoid the major risk factors (e.g., don’t be significantly overweight, don’t have high blood pressure), and take into account the serious costs in time and effort to both become well-informed and follow through on dietary changes, I don’t think most changes are worth implementing.

  2. I also prefer the East coast metric. When in doubt, I treat spatial and temporal components separately and just check to make sure that the Noether charges generate the Poincare algebra. This is especially helpful when dealing with gauge charges, which flip-flop the relative signs of the spatial and temporal components.

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