Science

Randi Foundation changing $1M challenge rules

Wired reports that the James Randi Educational Foundation is changing the rules for its million-dollar cash prize to anyone who can perform a psychic or supernatural ability under controlled conditions, to better focus on high-profile charlatans and spend less time testing people with obvious schizophrenia or other delusions. As of April 1st, if you want to apply for the prize you need to have some sort of media profile about their power and a letter from an academic who has seen their ability. (Thanks to Janie for the link!)

When do we choke under pressure?

Cognitive Daily has a nice summary of a study showing that people tend to choke under pressure on tasks that use your working memory, but actually do better under pressure on so-called information-integration tasks that require less working memory.

Evolution and the Samurai Crab

I wasn’t planning on posting anything for the Carl Sagan blog-a-thon marking the 10th anniversary of his death, but as it happens I recently discovered something I’d always remembered from Sagan’s 1978-79 TV show Cosmos was probably wrong.

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I still have a mental image of Sagan sitting in a boat talking about how for millennia Japanese fishermen would throw back crabs that resembled a human face, thinking it might be the spirit of an ancient samurai. Over the years, he explained, these returned crabs bred to look even more like human faces, and the result of this unintentional artificial selection is the so-called samurai crabs, which bear a striking resemblance to the face of a samurai.

It’s a great story which has been around at least since a 1952 Life Magazine article by evolutionary biologist Julian Huxley. But according to a 1993 article by crustacean evolutionary biologist Joel Martin it’s almost certainly false. He points out that, though the myth that the crabs in the Sea of Japan are the ghosts of defeated Heike samurai is fairly old, there are three reasons the face-like quality of the crabs can’t be due to selective fishing:

  1. Many crabs look like human faces, whether or not they are from the Sea of Japan or in regularly fished waters. The grooves that make the outline of the face are caused by supportive ridges that serve as sites for muscle attachments.

  2. Fossils of crabs closely related to the samurai crab also resemble human faces, even though they predate man’s appearance on earth.

  3. Most damning of all, the fishermen who make their living from the Sea of Japan don’t eat any of the samurai crab regardless of what they look like: they don’t grow any bigger than 1.2 inches across the back, so fishermen always just throw them back (or rather, they never bother to retrieve them from their nets in the first place).

It’s a shame that the story of unintentional artificial selection isn’t true, because it really is a great teaching story about evolution. The fact that I still remembered it enough to go searching on Wikipedia for “samurai crab” 27 years after I saw the original program may be the best testament to Carl Sagan I can give.

How your body processes soda

Via Healthbolt, how your body processes Coke or any other sugary caffeinated soda. I’m interested in seeing the citations, which the author promises he’ll link to. (Thanks to Aaron for the link!)

Earliest sunset of the year

A bit of trivia: even though the Winter Solstice isn’t for another couple weeks, tomorrow will be the earliest sunset of the year (about 4:55 PM in San Francisco). That’s because even though the days will keep getting shorter until December 22nd, sunrise will be getting later even faster.

(Calculated over at Express Tech’s Sunrise and Sunset Calculator, which is only one I could find that includes seconds.)

Pieces of pi at Washington Park Station

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I was in the Washington Park MAX Station in Portland yesterday, which includes a core sample taken during the tunnel’s construction along with a 16-million-year timeline showing when each sample had been at the Earth’s surface. Etched into the wall along the timeline include technical and mathematical discoveries, including 107 digits of pi. Only, I noticed as I read through the digits, it’s wrong. The first row is correct, but the rest looks random. My friend and I speculated on our ride back why that might be. Was it an estimate, the result of calculating only the first several terms of an infinite series? A deliberate retelling of an historically significant blunder? A secret code left by the artist that translates to “help, I’m being held captive in a Portland artist colony!”?

Google to the rescue, it turns out this was either a clever way of representing the first 1000 digits of pi, or more likely was a simple misreading of the reference book from which the number came. As Mark Cowan points out in Underground Pi, the numbers etched in stone in the subway were taken from A History of Pi, which prints the digits in rows of 10 groups of 10 digits. The artist clearly took his numbers from the first column in that reference, thus printing the first thru tenth fractional digits, the 101th-110th, etc.

What does cloning do to the stem-cell debate?

OK, so the whole stem-cell debate in congress mostly revolves around the fac that, as Bush put it, “…extracting the stem cell destroys the embryo, and thus destroys its potential for life,” and opponents of embryonic stem-cell research suggest scientists should focus on adult stem cells that don’t have that potential. Which just makes me wonder, what happens if (or when) science advances to the point where human cloning is possible? Would adult stem cells be verboten as well? What happens when blood cells and dead skin have the “potential for life?”

Singing sands

OK, this is too cool. From Physics News Update (with thanks to Strata for the link):

For centuries, world travelers have known of sand dunes that issue loud sounds, sometimes of great tonal quality. In the 12th century Marco Polo heard singing sand in China and Charles Darwin described the clear sounds coming from a sand deposit up against a mountain in Chile. Now, a team of scientists has disproved the long held belief that the sound comes from vibrations of the dune as a whole and proven, through field studies and through controlled experiments in a lab, that the sounds come from the synchronized motions of the grains in avalanches of a certain size.

You can hear recordings of singing avalanches from CNRS labs, and Prof. Melany Hunt at caltech has some movies of creating singing avalanches on her website.

EIT on a chip

From this month’s Nature (if you don’t feel like registering, try one of these):

A two-laser trick that renders opaque media transparent can be achieved in systems of tiny optical resonators — with potentially profound consequences for optical communication and information processing.

The discovery of electromagnetically induced transparency (EIT) — an unusual effect that occurs when two laser beams interact within an optical material — and the use of novel techniques to fabricate ever smaller structures to control light have been recent exciting developments in optical physics. Writing in Physical Review Letters, Xu et al. neatly combine the two, demonstrating an on-chip, all-optical analogue of EIT based on the response of coupled optical microresonators. The result may open up untrodden pathways in photonics, offering prospects of smaller, more efficient devices for the manipulation and transmission of light.

(Thanks to eLMo for the link!)