The National Institutes of Health is going to require a sex-ratio balance in animal studies, and Tabitha M. Powledge explains what that means: "Even some researchers who thoroughly approve of organizing a piece of research so that it's possible to sort out any effects that differ by sex have been made gloomy by this announcement." Also, Nate Silver's fivethirtyeight.com trips again; bats, camels and MERS; and a new book on the genetics of race.
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