It is therefore less sensitive to the precise chemical make-up of the site.

ECONOMIST: Nanotechnology in biology

Since 1991, working separately, the two have found how each protein can be sensitive to more than one smelly chemical, in different amounts, and how any given chemical activates several proteins at once, much like a unique musical chord which the brain then identifies as a smell.

ECONOMIST: The Nobel prizes

G4S provides guards for nuclear power plants, chemical plants, government buildings and other sensitive sites, and it is prohibited by state law from hiring people with felony convictions as security officers.

WSJ: James Bovard: Perform Criminal Background Checks at Your Peril