Pictured is a computer-generated RNA structure tied in a trefoil knot. C. Micheletti et al. screened the several thousand RNA chains in the Protein Data Bank for the presence of knots. Only three ...

Birdsfoot trefoil is the best long-lived legume for growing in a mixture with Kentucky bluegrass as permanent pasture in the northern half of Indiana. It competes remarkably well with bluegrass under ...

BBC Moscow correspondent Sarah Rainsford was given rare access to the Russian base, known as Arctic Trefoil. Camera: Anton Chicherov Producer: Liza Shuvalova Residents applauded as the lights came ...