By tracking eye movements in zebrafish, researchers identified four different types of sleep, analogous to the complex sleep patterns of humans and other animals.
The types of Ebola and hantavirus panicking officials are very different from the species identified decades ago, raising new questions about how to respond.
For a split second, a fireball outshone the rivers of molten lava flowing from the Philippines’ most active volcano.
Companies say it’s a better way to dispose of the Cold War-era material — and fix a shortage of nuclear fuel. But the plan has also faced criticism.