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Left-handed quarks, baby fusion-steps, gene politics

Left-handed quarks (Science Magazine)

Electrons spin, and so can spin clockwise or counterclockwise. If you shoot a beam of electrons at an atomic nucleus, you would not expect it to make any difference, which way they were spinning. But it does, because one of the nuclear forces, the weak force, is fundamentally asymmetrical. The scatter pattern for the clockwise beam is not a mirror image of the pattern for the counterclockwise beam.

That's for interactions at the level of the nucleus. But what about at the level of quarks, the particles that make up the protons and neutrons that make up nuclei? They have finally managed to get electron beams powerful enough to pry their way into neutrons and bound off individual quarks. The same asymmetry appeared. Which was exactly what was expected. This is confirmation of the existing physics theories, and also puts constraints on any new theories.

Baby fusion-steps (Discover)

Fusion is hard to do. But the physicists are Lawrence Livermore Labs have made some progress. They have achieved fusion, for about a second, by firing a massive laser into a fuel pellet, and the fusion produced more energy than went into the laser. It still didn't produce more than 1% of the total energy used in the system, the breakeven point. But it produced more than ten times as much energy as previous similar experiments.

Gene politics (New Scientist)

Genetic analysis of American Indians from Canada and Latin America confirms that they all descend from a small population that crossed over from Siberia several thousand years ago. Why no samples from the US? Because US Indians do not trust geneticists, ever since the Havasupai tribe gave DNA samples to Arizona State University, to research their tendency to diabetes, and the university also used the samples to study inbreeding rates and the Siberian question. Not only did the Havasupai resent the unsanctioned use, they resented the Siberian issue, since their own origin myths say they were created in the Grand Canyon.

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