Running. Photo by Mark Sadowski.

• Diff’rent strokes for diff’rent muscles. Most human leg muscles operate efficiently in walking and running, but different muscles are at peak efficiency at different speeds.
• Harm reduction reduces harm. Aggressive and innovative public health measures in British Columbia has dramatically cut new HIV infections.
• Getting to zero. What to do about false positive tests for HIV infection.
• Not so vestigial after all? The function of the human appendix may be in recovery from gastrointestinal infections.
• Someone’s gotta provide those articles. A consideration of whether it’s okay to write for Playboy.
• Or, you know, there’s more to “fitness” than sperm motility. In which being attracted to deep-voiced men may not make adaptive sense.
• A depressing thought. Could failures of antidepressants in placebo-controlled tests be due to bad patient sampling?
• That’s one fast camera. New optical and computational tools can capture light waves in motion.
• Convergence in the slow lane. Two-and three-toed sloths have apparently evolved their similar forms independently.
• Requiescat. Pioneering geneticist James F. Crow.
• The power of branding. An elaborately double-blind trial demonstrates that professional violinists can’t tell a Stradivarius from a brand-new violin.

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