Bottled water consumption, which has more than doubled globally in the last six years, is a natural resource that is heavily taxing the world's ecosystem, according to a new US study.

After running a maze, rats mentally replay their actions - but backward, like a film played in reverse, a researcher at the Picower Institute for Learning and Memory at MIT reports Feb. 12 in the advance online edition of Nature.

China on Sunday issued its first detailed policy guidelines on dealing with its exploding HIV/AIDS epidemic, including requiring local governments to offer free drugs and testing.