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Noted
March/April 2009
Galaxies stop producing stars at a relatively young
age. Until now, astronomers thought the shutdown was due to peaking of the
activity of the supermassive black hole at each galaxy’s center. But an
analysis of 177 galaxies by postdoctoral researcher Kevin Schawinski and his
colleagues showed that stars stopped forming well before the high point of
galactic nuclei activity. The work appeared in the February 10 Astrophysical
Journal Letters.
A four-inch, 390-million-year-old fossil is the
missing link in the evolution of the front claws of horseshoe crabs and
scorpions. Schinderhannes bartelsi, named in part to honor a late-eighteenth-century German
bandit, was described by paleontologist and Peabody Museum director Derek
Briggs and his colleagues in the February 6 issue of Science. It was discovered in a slate
quarry in Germany.
Only a tiny number of animal species undergo a
natural sex change. But the biological costs of "sequential hermaphroditism," though significant, are not sufficient to account for its rarity, report
evolutionary biologist Suzanne Alonzo and graduate student Erem Kazancioglu in
the March issue of the American Naturalist. They are exploring whether factors such as mating
and parental care are at work.
In 2007, the U.S. Supreme Court ruled that a Georgia
policeman was justified in engaging in a high-speed chase captured on
videotape. "No reasonable person" who viewed the tape could have thought otherwise,
the justices wrote. Law School professor Dan Kahan showed the tape to 1,350
people of differing culture, politics, economic circumstances, race, gender,
and age. Kahan and his colleagues found that among certain subgroups, as many
as 65 percent of these reasonable people disagreed with the court majority. The
study appeared in the January Harvard Law Review.  |
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