Category: Science & Technology

The trouble with fMRI.

Science News: Trawling The Brain

The 18-inch-long Atlantic salmon lay perfectly still for its brain scan. Emotional pictures—a triumphant young girl just out of a somersault, a distressed waiter who had just dropped a plate—flashed in front of the fish as a scientist read the standard instruction script aloud. The hulking machine clunked and whirred, capturing minute changes in the salmon’s brain as it assessed the images. Millions of data points capturing the fluctuations in brain activity streamed into a powerful computer, which performed herculean number crunching, sorting out which data to pay attention to and which to ignore.

By the end of the experiment, neuroscientist Craig Bennett and his colleagues at Dartmouth College could clearly discern in the scan of the salmon’s brain a beautiful, red-hot area of activity that lit up during emotional scenes.

An Atlantic salmon that responded to human emotions would have been an astounding discovery, guaranteeing publication in a top-tier journal and a life of scientific glory for the researchers. Except for one thing. The fish was dead.

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Scale model of the Earth and the Moon, with a beam of light travelling between them at the speed of light. It takes approximately 1.26 seconds.

Wikipedia, via Jorn Barger.

Well, maybe…

The Collider, the Particle and a Theory About Fate

More than a year after an explosion of sparks, soot and frigid helium shut it down, the world’s biggest and most expensive physics experiment, known as the Large Hadron Collider, is poised to start up again. In December, if all goes well, protons will start smashing together in an underground racetrack outside Geneva in a search for forces and particles that reigned during the first trillionth of a second of the Big Bang.

Then it will be time to test one of the most bizarre and revolutionary theories in science. I’m not talking about extra dimensions of space-time, dark matter or even black holes that eat the Earth. No, I’m talking about the notion that the troubled collider is being sabotaged by its own future. A pair of otherwise distinguished physicists have suggested that the hypothesized Higgs boson, which physicists hope to produce with the collider, might be so abhorrent to nature that its creation would ripple backward through time and stop the collider before it could make one, like a time traveler who goes back in time to kill his grandfather.

Holger Bech Nielsen, of the Niels Bohr Institute in Copenhagen, and Masao Ninomiya of the Yukawa Institute for Theoretical Physics in Kyoto, Japan, put this idea forward in a series of papers with titles like “Test of Effect From Future in Large Hadron Collider: a Proposal” and “Search for Future Influence From LHC,” posted on the physics Web site arXiv.org in the last year and a half.

According to the so-called Standard Model that rules almost all physics, the Higgs is responsible for imbuing other elementary particles with mass.

“It must be our prediction that all Higgs producing machines shall have bad luck,” Dr. Nielsen said in an e-mail message. In an unpublished essay, Dr. Nielson said of the theory, “Well, one could even almost say that we have a model for God.” It is their guess, he went on, “that He rather hates Higgs particles, and attempts to avoid them.”

This malign influence from the future, they argue, could explain why the United States Superconducting Supercollider, also designed to find the Higgs, was canceled in 1993 after billions of dollars had already been spent, an event so unlikely that Dr. Nielsen calls it an “anti-miracle.”

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Geoff Pullum at Language Log. He’s right, I suppose, but this is one of those cases in which any apology at all must be too little, too late. Too late not just for the obvious reason that any apology for this sorry series of events would have been too late after the fact, but also because it can no longer come (or at least does not come) from those directly responsible (Brown was born three years before Turing died). Still.

For Alan Turing, a real apology for once

In an age where (as Language Log has often had occasion to remark) many purported public apologies are just mealy-mouthed expressions of regret (“I’m sorry it all happened”), or grudging self-exculpatory conditionals (“If some people think I shouldn’t have said it, I’m sorry they were upset”), it is good to see a genuine and direct apology for once, addressed (though more than half a century too late) to a man who deserved admiration, gratitude, and respect, but was instead hounded to death. The UK Prime Minister, Gordon Brown, has released a statement regarding the treatment of Alan Turing in the early 1950s, and the operative words are:

…on behalf of the British government, and all those who live freely thanks to Alan’s work I am very proud to say: we’re sorry, you deserved so much better.

That’s how to say it (ignoring the punctuation error — the missing comma after work): not a bunch of evasive mumbling about how unfortunate it all was, but a simple “We’re sorry.”

Turing did indeed deserve so much better. He created modern theoretical computer science; opened fundamental new areas of mathematical logic; made very important contributions to other areas of mathematics (e.g., the technique known as Good-Turing frequency estimation in statistics); and most importantly, he gave up his academic work during the Second World War to work at Bletchley Park on the extremely difficult task of decrypting German communications encrypted with the Enigma machine. The Bletchley Park team did succeed, and thus the Royal Navy became able to read the content of all the Nazis’ messages to U-boats in the North Atlantic. It was a crucial turning point in the war. But a mere seven years later, a young man shared Turing’s bed for the night in Manchester, and later helped someone burgle the house, and Turing naively reported the theft to the police. The police reaction was to arrest Turing, because they guessed what had been going on. “Gross indecency” was the charge (it is the British legal euphemism for cocksucking). Turing had a choice between serving prison time or agreeing to chemical castration, a medicalized “cure” for his presumed abnormality. He bore the latter for two years and then took cyanide. The way British mid-20th-century sex law drove him to suicide was genuinely something for the country to be ashamed of. It was good to see the official apology (which hundreds of eminent scientists had asked the Prime Minister to express).

Ars Technica: “Anonymized” data really isn’t—and here’s why not

The Massachusetts Group Insurance Commission had a bright idea back in the mid-1990s—it decided to release “anonymized” data on state employees that showed every single hospital visit. The goal was to help researchers, and the state spent time removing all obvious identifiers such as name, address, and Social Security number. But a graduate student in computer science saw a chance to make a point about the limits of anonymization.

Latanya Sweeney requested a copy of the data and went to work on her “reidentification” quest. It didn’t prove difficult. Law professor Paul Ohm describes Sweeney’s work:

At the time GIC released the data, William Weld, then Governor of Massachusetts, assured the public that GIC had protected patient privacy by deleting identifiers. In response, then-graduate student Sweeney started hunting for the Governor’s hospital records in the GIC data. She knew that Governor Weld resided in Cambridge, Massachusetts, a city of 54,000 residents and seven ZIP codes. For twenty dollars, she purchased the complete voter rolls from the city of Cambridge, a database containing, among other things, the name, address, ZIP code, birth date, and sex of every voter. By combining this data with the GIC records, Sweeney found Governor Weld with ease. Only six people in Cambridge shared his birth date, only three of them men, and of them, only he lived in his ZIP code. In a theatrical flourish, Dr. Sweeney sent the Governor’s health records (which included diagnoses and prescriptions) to his office.

Boom! But it was only an early mile marker in Sweeney’s career; in 2000, she showed that 87 percent of all Americans could be uniquely identified using only three bits of information: ZIP code, birthdate, and sex.

Such work by computer scientists over the last fifteen years has shown a serious flaw in the basic idea behind “personal information”: almost all information can be “personal” when combined with enough other relevant bits of data.

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Bruce Schneier points to a paper on the statistics of coin-tossing. Summary of the summary: not random. One item:

If the coin is tossed and caught, it has about a 51% chance of landing on the same face it was launched. (If it starts out as heads, there’s a 51% chance it will end as heads).

In retrospect, this is not all that surprising. It’s good to keep in mind.

Commenter Michael Ash suggests a mechanism for compensating for the bias:

Flip the coin twice. If the first one is heads and the second tails, take one choice. If the first is tails and the second heads, take the other choice. If you get the same face both times, start over. This last part is key: you must start over and flip two more times, and keep flipping in pairs until you get two different faces. It’s not enough to just flip in sequence until you see a change. You have to completely discard the result and begin anew.

This works (I think), but only if the two flips are independent of each other, a non-trivial assumption.

You can generally trust xkcd to feed you the straight scoop. This piece is more than usually helpful. Listen, people: this is how we geeks do it. Really. Try this at home.

click it for a larger image

Too good not to pass along.

Brian via Liberman

Listen to this fine NPR story on crows recognizing individual people. There’s a video on the page as well, but the original story is better than the video.

Aside from the inherent interest of the immediate story, it’s a nice example of science at work in the wild, where unexpected observations are investigated, complete with controls and new opportunities for research.

BETELGEUSE SHRINKS

Betelgeuse, one of the brightest stars visible to the naked eye, has shrunk in diameter by more than 15 percent since 1993.

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In 1921, Betelgeuse became the first star for which astronomers measured a size. Over the years, different interferometers, observing Betelgeuse over a wide range of wavelengths, have recorded diameters for the star that disagree with each other by as much as 30 percent. That’s not surprising because stars often look considerably bigger or smaller at different wavelengths. But the star hasn’t previously been found to vary significantly in size at any one wavelength, Townes says.

As hefty as 15 suns, Betelgeuse is nearing the end of its life and could soon go supernova. Continued close monitoring of Betelgeuse could lead to a better understanding of the evolution of massive stars near the end of their lifetime.

via Jorn Barger

Via Jorn Barger and others, a glorious time-lapse video of the dust-dimmed center of the Milky Way rising. Watch it full-screen if you can.

Galactic Center of Milky Way Rises over Texas Star Party from William Castleman on Vimeo.

STS-125 is the Space Shuttle mission to update and repair the Hubble Space Telescope one last time. The second EVA (replacing gyros and batteries) is just now complete. I finally tracked down a real-time news feed that fits my needs; give it a try tomorrow.

Wikipedia has a nice article that includes a summary of the five EVAs.

In the last month or two, I’ve taken to using my MacBook Pro with an external monitor, keyboard and mouse, both at home and at my office. I don’t find a second monitor all that useful, so I went looking for a stand for the notebook that would minimize its footprint while not blocking access to its IO ports or DVD slot.

The purpose-built products I came across where either stunningly expensive, unavailable, or both. A friend suggested a cookbook holder, which sounded promising, but the wire holder I have was too flimsy for my largish (17″) notebook. But in searching for similar holders, I came across this:

It’s available via Amazon for $17 plus shipping. It’s sturdy, stable and attractive. I now have two, and recommend them for anyone with a similar application.

(On a related note, I was pleased to discover that you can get a very nice monitor for very little money, as long as you stay under 24″ or so. Even 24″ isn’t all that bad, but 22″ seems like a real sweet spot right now. I bought an HP w2207h for home use.)