Sound waves boost older adult’ memory, deep sleep

Gentle sound stimulation -- such as the rush of a waterfall -- synchronized to the rhythm of brain waves significantly enhanced deep sleep in older adults and tripled their ability to recall words, reports a new study. The goal is to make the new technology available for home use.

Redefining ‘species’

What is a species? Biologists -- and ornithologists in particular -- have been debating the best definition for a very long time. A new commentary published in The Auk: Ornithological Advances proposes a novel concept: that species can be defined based on the unique coadaptations between their two genomes, one in the nuclei of their cells and the other in their mitochondria.