Overcoming obstacles, scientists have created stable embryonic stem cells from rats. Researchers hope their method will prove useful as a general recipe for isolating stem cells from other mammals.

A new study shows some male dinosaurs may have been the primary caretakers of their young. (p. 14)

Data compilation by region, type of hazards shows deaths from more frequent events accumulate into significant numbers. Lightning strikes also high on the list.

Large genomic studies show body rhythms, melatonin may influence sugar levels in the blood. (p. 5)

Molecules are hot. They zip, spin and vibrate with frenetic motion. They jiggle and twist on the inside and bounce on the outside, imparting structure and physical properties to nearly everything that exists. But by achieving temperatures colder than any in the natural world, physicists can almost stop these speed demons cold. Like surgeons who slow a beating heart by packing ice around a patient’s chest, physicists have recently coaxed molecules into ultracold states in which motion is nearly gone. Researchers are left with intriguing, exquisitely controllable new specimens to po... (p. 22)

Scientists describe the shape of a protein required for conception. These new molecular details will lead to an improved understanding of how sperm and egg unite. (p. 15)

Nearby lizards more likely to get the message if its preceded by push-ups