Using a simple equation, the index gives a measure of how close populations of each of these 'functional groups' are to those in pre-industrial times.

Airports are no longer a place of education and fun; they are the most sophisticated of security sites.

"These are very sophisticated machines, " he said.

I mean, in general, you will want, once you have a set of nice, natural variables, you will want to look mostly at situations where one of the variables changes.

And academics are using sophisticated techniques to test whether popular medicines are safe.