Links for December 2015

[continue reading]

Links for November 2015

  • Finally someone wrote the article I wanted written about one of the infuriating parts of living in NYC: no countdown clocks for subway trains, for no good reason.

    That’s why the MTA has tried to associate CBTC [a enormous overhaul of the signal system for the subway] with countdown clocks. New York riders crave realtime information about trains. They don’t care how they get it. So when Transit wants to drum up support for an obscure, costly, many-decades-long capital project to upgrade to CBTC, they always point to the clocks. (“Sustained Investment Makes Real-Time Information Possible,” declares one 2012 press release.) Reporters, struggling to make sense of a half-dozen interrelated projects, follow the MTA’s lead and assume that realtime train-location information depends on signal upgrades.

    But that would make for some pretty expensive clocks, and it would make them awfully long in arriving. The F train, for instance, if it had to wait for CBTC to get realtime arrival information, wouldn’t see it until 2035.

    It’s a misleading narrative. You can get countdown clocks without touching the signals. The MTA knows this.

    An embarrassing symptom of municipal sclerosis.

  • An analysis of the “rolling shutter” distortion effects in some popular pictures of propellors and other fast moving objects.
[continue reading]

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.

[continue reading]

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.

[continue reading]

Links for August 2015

Didn’t quite make it on time this month…

[continue reading]

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.

[continue reading]

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.

[continue reading]

Links for May 2015

  • Are those cocky physicists-turned-biologists living up to their reputation and embarrassing themselves by ignoring epistasis, epigenetics, and gene-gene interactions? Steve Hsu says no, citing the strong success of additive models in twin studies, and the theoretical explanation from stability for the same.
  • An excellent video (from here) depicting a 1956 vision of the future of autonomous driving.

    (H/t Tyler Cowen.)
  • I’m pretty skeptical of the feasibility Elon Musk’s Hyperloop concept, based on earlier criticism, but an unaffiliated company just signed a contract for the land to build a 5-mile test track, and Musk himself claims a different test is coming to Texas. Note however that the first company is long on hype, short on details.
  • All these amateurs and celebrities have been talking about the long risk of recursively self-improving artificial intelligence, but don’t the actual AI researchers think this is a bunch of hooey? Only if you cherry pick, notes Scott A. In particular, if you’re willing to trust the survey skills of people with skin in the game, then

    …a survey of AI researchers (Muller & Bostrom, 2014) finds that on average they expect a 50% chance of human-level AI by 2040 and 90% chance of human-level AI by 2075.

[continue reading]

Links for April 2015

  • The recently completed Effective Altruism Handbook is a collection of key articles which cover a lot of the movement’s basic arguments. It’s available here as a PDF. There are also two new EA books coming out by Peter Singer and Will MacAskill (with annoyingly similar titles…). And here is the Huffington Post’s take on all the noise at Harvard.
  • Authorea authors write on the problems with peer review associated with hyperspecialization:
    [T]he average number of authors per paper has been steadily increasing in the last few decades, while the number of referees per paper has not.

    Doom

  • Relatedly, the new Leiden Manifesto argues against giving bibliometrics (h-index, etc.) a leading role in the hiring and funding processes. Although I agree with much of it, they take a wishy-washy stance that dilutes its effectiveness. I once compared the objectivity of citation metrics to a vote by spectators about who ran the fasted 100 yard dash, and my opinion has only gotten more pessimistic since then.
  • Some good modern discussion of the theory of a Land Value Tax by Bryan Caplan, Jeff Kaufman, and Noah Smith. Some of their disagreement is semantic (i.e., compared to which platonic ideal are we calling something a “friction”, versus an inherent problem?), but it’s still illuminating.
[continue reading]

Links for March 2015

  • The eclipse seen from an airplane, time lapse:
  • A 2003 proposal [PDF] to send a probe to the center of the earth riding a $60 million slab of molten iron:

    This proposal is modest compared with the space programme, and may seem unrealistic only because little effort has been devoted to it. The time has come for action.

  • Will the paternoster be reborn?:

    (HN Comments.) This could alleviate a serious limiting factor for extremely tall skyscrapers, which use a surprisingly large fraction of their square footage for elevators.
  • Toward a systematic assessment of the rent hypothesis.

    Rent…is…a payment for a resource in excess of its opportunity cost, one that instead reflects market power. There has been, for the last few years, a “big idea” floating around the economics conversation that these rents are growing — that unearned gains are eating up an larger share of income. Let’s call it “the rent hypothesis.” It’s an appealing idea from a certain perspective. It seems to explain a lot.

    Trying to spot rents is, in this sense, a bit like trying to spot a black hole… the idea is to spot rents by what is missing, by the presence of a contradiction where only rents can fill the gap.

[continue reading]

Links for February 2015

[continue reading]

Links for January 2015

  • There’s been some coverage of using etching to produce superhydrophobic metals. Unfortunately, it probably suffers from the same durability issues (no resistance to being destroyed through normal wear) as previous techniques that used special chemical coatings.
  • A funnel plot is a quick graphical way to check for publication bias on a topic.
  • Apparently, the best way to avoid a fight with a confrontational Red Kangaroo (the largest kangaroo species) is to give a deep cough. This is a signal of submission by subdominant males, and can assure the dominant male that you aren’t challenging him. Otherwise…

  • Daniel Dennett, synthesizing Anatol Rapoport, on how to compose a successful critical commentary:
    • You should attempt to re-express your target’s position so clearly, vividly, and fairly that your target says, “Thanks, I wish I’d thought of putting it that way.
    • You should list any points of agreement (especially if they are not matters of general or widespread agreement).
    • You should mention anything you have learned from your target.
    • Only then are you permitted to say so much as a word of rebuttal or criticism.

    If only the same code of conduct could be applied to critical commentary online, particularly to the indelible inferno of comments.

[continue reading]

Links for December 2014

  • Steve Hsu notes that BGI has applied preimplantation genetic diagnosis (PGD) using next-generation sequencing techniques. Previous uses of PGD have only used simple screening methods, like searching for single-nucleotide polymorphisms, to avoid implanting embryos with a handful of well-understood genetic defects (which are then destroyed). Next generation methods have the potential to sequence most/all of the genome, allowing for traits influences by many genes to be selected for, like height and intelligence.
  • Crab housing exchange.
  • That the National Reconnaissance Office publicly releases the mission patches for their highly classified satellites is well-known on the internet, but I hadn’t realized that there was reason to think that classified details had been accidentally leaked through them in the past.
  • If correct, this is a surprisingly comprehensive and intuitive answer to many aspects of human bilateral (a)symmetry:

    Most of our asymmetry is due to just two organ systems: the GI tract and the heart. The concept that best explains the shape of both of these systems is the idea that a long organ that has to fit in a small body does so by being wound up.

    The heart could be composed of a linear arrangement of a pump, the lungs, and then a second pump.

[continue reading]

Links for November 2014

Almost all the links this month are space related. I promise I spend time thinking about other things but…there’s just a lot of cool space-related links on the internet.

  • Video of the night sky with the stars stabilized so you can watch the ground spin around.
  • For several years the ESA worked on a spacecraft that would test the idea of deflecting a comet with a high-speed impactor. It was brilliantly named Don Quijote, with the rash impactor craft “Hidalgo” rushing in to the target with the observation craft “Sancho” watching from a safe distance. Unfortunately, it looks like the project stalled years ago, but a proposed joint NASA-ESA mission Asteroid Impact & Deflection Assessment (AIDA) could carry the torch [PDF] by targeting the asteroid 65803 Didymos. Didymos is actually a binary system, with a large primary asteroid and a smaller secondary asteroid orbiting it. When the impactor strikes the primary (speed ~ 6.25 km/s), it would induce perturbations to the orbit of the secondary observable from Earth. A 2019 launch and 2022 impact date have been chosen so that Didymos will be passing close to the Earth and the impact event will be visible to ground-based radar.
[continue reading]

Links for October 2014

  • Total moving face reconstruction“:

    We present an approach that takes a single video of a person’s face and reconstructs a high detail 3D shape for each video frame. We target videos taken under uncontrolled and uncalibrated imaging conditions, such as youtube videos of celebrities. In the heart of this work is a new dense 3D flow estimation method coupled with shape from shading. Unlike related works we do not assume availability of a blend shape model, nor require the person to participate in a training/capturing process. Instead we leverage the large amounts of photos that are available per individual in personal or internet photo collections. We show results for a variety of video sequences that include various lighting conditions, head poses, and facial expressions.

  • What’s changed since the days when theft was worse than murder? I would really love to see whether a “historical economist” (or whatever those are called) could estimate the statistical value of a human life as defined by people’s own revealed preferences. This is the sort of calculation where we infer how much each of us values our own lives based on the amount we are willing to pay to avoid small chances of death.

[continue reading]