Arms control. Verification experts puzzled over North Korea's nuclear test.

Stressed Cells Cause Gray Hair. If you’ve ever blamed your gray hair on stress, you weren’t far from the truth. Genotoxic stress—the kind that can damage a cell’s DNA—causes hair to whiten over time, according to a new study. The results challenge accepted ideas about how stem cells age and may eventually lead to new ways to prevent graying and treat the… CONTINUE READING