Links for February 2016

Just in the nick of time…

  • Eliezer Yudkowsky has a large Facebook thread resulting in many public bets on the Lee Sedol vs DeepMind’s AlphaGo match.

    In particular, I have bet Carl Shulman $100 at even odd that Sedol will win. (For the record, my confidence is low, and if I win it will be mostly luck.) The match, taking place March 9-15, will be streamed live on YouTube.

    Relatedly, here is excellent (if slightly long winded) discussion of why the apparent jump in AI Go ability may be partially attributable to a purposeful application of additional computing power and researcher GO-specific expertise, rather than purely a large jump in domain-general AI power.

  • SciHub has been in the news recently, and I guess they decided to upgrade their appearance.
  • Victorian Humor.
  • Want a postdoc doing theoretical physics, machine learning, and genomics? You’re in luck.
  • Luke Muehlhauser has good quote from Bill Gates on AI timelines.
  • Assortative Mating—A Missing Piece in the Jigsaw of Psychiatric Genetics“.

    Why are psychiatric disorders so highly heritable when they are associated with reduced fecundity? Why are some psychiatric disorders so much more highly heritable than others? Why is there so much genetic comorbidity across psychiatric disorders?

    Although you can see assortative mating for physical traits, like height and weight, with your own eyes, the correlation between spouses is only approximately 0.20 for these traits. For personality, assortative mating is even lower at approximately 0.10. In contrast, Nordsletten and colleagues1 find an amazing amount of assortative mating within psychiatric disorders. Spouse tetrachoric correlations are greater than 0.40 for attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and schizophrenia.

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Links for January 2016

  • Mechanistic insight into schizophrenia?
  • Wide-ranging (and starry-eyed) discussion on HackerNews about what startup can do to make the world a better place.
  • All six naked-eye-visible planets in one wide-angle image.

    (Source.) You can see the current configuration of the solar system here.
  • Holden Karnofsky argues persuasively that selection bias implies that we should have fewer and more high-quality studies than we would in a hypothetical world with ideal, unbiased researchers.

    Chris Blattman worries that there is too much of a tendency toward large, expensive, perfectionist studies, writing:


    …each study is like a lamp post. We might want to have a few smaller lamp posts illuminating our path, rather than the world’s largest and most awesome lamp post illuminating just one spot. I worried that our striving for perfect, overachieving studies could make our world darker on average.

    My feeling – shared by most of the staff I’ve discussed this with – is that the trend toward “perfect, overachieving studies” is a good thing…

    Bottom line. Under the status quo, I get very little value out of literatures that have large numbers of flawed studies – because I tend to suspect the flaws of running in the same direction. On a given research question, I tend to base my view on the very best, most expensive, most “perfectionist” studies, because I expect these studies to be the most fair and the most scrutinized, and I think focusing on them leaves me in better position than trying to understand all the subtleties of a large number of flawed studies.

    If there were more diversity of research methods, I’d worry less about pervasive and correlated selection bias.

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Links for December 2015

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Links for November 2015

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Links for October 2015

  • More well-deserved praise for the Stanford Encyclopedia of Philosophy. Lots to be learned from how the SEP was created. A key chicken-or-egg problem:

    …several SEP authors and editors…said that the encyclopedia is used frequently both as a reference and as a teaching tool. This means that philosophers are some of the SEP’s core readers, and they can alert authors or subject editors to incorrect or insufficient entries.

    Stanford does pay most of the operating costs. But the SEP has a paid staff of only three—Zalta, Nodelman, and Allen—plus five other Stanford employees who spend 20% of their time on technical support. Neither the authors, nor the dozens of subject editors, get so much as a dime for their troubles.

    To pay running expenses not covered by Stanford, the team obtained nearly $2 million in grants over the first 15 years. But they wanted something more sustainable… The SEP asks academic libraries to make a one-time contribution [that now provides around a third of the budget]. That doesn’t get them access to the SEP, since it’s already freely accessible, but they enjoy some extra “member benefits,” like the ability to use their own branding on a version of the encyclopedia, and to save the full archives.

    Moreover, their money goes into an SEP endowment, managed by the same company that takes care of Stanford University’s endowment of over $20 billion. If the SEP ever shuts down, Stanford promises to give the libraries that contributed to SEP all their money back, with interest. “It became a no-risk investment for the libraries, and it’s a way for them to invest in open access,” says Zalta.

    Libraries were enthusiastic. The SEP was able to raise over $2 million from the long list of contributors, and Stanford added $1 million to the library endowment.

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Links for September 2015

  • Chris Blattman on the Center for Global Development’s endorsement of cash transfers. (Report.)
  • Here’s to several decades of grinding out a couple of decimal places to parameterize a charged Higgs:

    Three years ago the BaBar collaboration at SLAC measured the branching ratios for B-meson decay to produce either a muon or a tau. For two slightly different decays, they found 2σ or greater deviations from the democratic standard-model expectation. Now the LHCb collaboration at CERN has confirmed the BaBar result for one of the decays. In a preprint, the Belle group at KEK in Japan has also announced results that show a similar though less strong deviation from the standard model. The figure below (from the Heavy Flavor Averaging Group) shows the branching ratios (R) measured by the groups for the two decays, denoted D and D*, along with the standard-model prediction. Taken together, the groups’ measurements have struck a 3.9-σ blow to the principle of lepton democracy. If they hold up, the standard model will have to be modified—perhaps by the addition of a new charged Higgs boson, whose interactions would depend on mass.

    Importantly, this is a combination of several experiments rather than easily attributable to a systematic mistake in one.

  • Advanced LIGO turns on after completing upgrade. From now on, LIGO will be able to notify any number of 75 astronomical observatories around the world who have agreed to, at a moment’s notice, point their telescopes to the sky in search of light signals corresponding to possible gravitational wave detections.
  • New data on great filter from density of habitable planets.

    these new results offer little support for the scenario where we have a good chance of growing out into the universe and meeting other aliens before a billion of years have passed.

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Links for August 2015

Didn’t quite make it on time this month…

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Links for July 2015

  • Cochrane review finds that there is little evidence that water fluoridation has any dental benefits, although it does not dispute that fluoride in toothpaste reduces tooth decay:

    Studies that attest to the effectiveness of fluoridation were generally done before the widespread usage of fluoride-containing dental products like rinses and toothpastes in the 1970s and later, according to the recent Cochrane study. So while it may have once made sense to add fluoride to water, it no longer appears to be necessary or useful, Thiessen says.

    It has also become clear in the last 15 years that fluoride primarily acts topically, according to the CDC. It reacts with the surface of the tooth enamel, making it more resistant to acids excreted by bacteria. Thus, there’s no good reason to swallow fluoride and subject every tissue of your body to it, Thiessen says.

    Another 2009 review by the Cochrane group clearly shows that fluoride toothpaste prevents cavities.

  • Earth rise, as seen by a Japanese lunar orbiter
  • Dermatomes:

    A dermatome is an area of skin that is mainly supplied by a single spinal nerve.[1] There are 8 cervical nerves (C1 being an exception with no dermatome), 12 thoracic nerves, 5 lumbar nerves and 5 sacral nerves. Each of these nerves relays sensation (including pain) from a particular region of skin to the brain…

    Along the thorax and abdomen the dermatomes are like a stack of discs forming a human, each supplied by a different spinal nerve. Along the arms and the legs, the pattern is different: the dermatomes run longitudinally along the limbs. Although the general pattern is similar in all people, the precise areas of innervation are as unique to an individual as fingerprints.

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