Within an hour of a person falling asleep, slow waves will have covered his entire cortex, affecting every nerve cell in it.

ECONOMIST: Memory formation

This fitted the prediction that the downscaling slow-waves would be strongest in those parts of the brain where the most changes had taken place during the day.

ECONOMIST: Memory formation

It said independent tests in Arctic conditions have shown that ice can slow oil weathering, dampen waves, prevent oil from spreading over large distances, and allow more time to respond.

BBC: MPs' call to halt Arctic drilling amid safety concerns