Quantitative relationships between how frequently a word is used and how rapidly it changes over time raise intriguing questions about the way individual behaviours determine large-scale linguistic and cultural change.

When we observe laser light, we typically measure its intensity, and so wave amplitude. The phase, which encodes further details of the laser's internal workings, was obscure — but fresh light is being shed on it.

Single genes, chromosomal regions and even entire genomes can undergo duplication. What good can come of these extra copies? Evolution seems to use several tricks to take advantage of the situation.