Astronomy: Fossilized rivers suggest warm, wet ancient Mars UK: Roman temple dig under way at Keynsham cemetery North America: Site with clues to fate of fabled Lost Colony may be saved Polynesia: Forensic analysis of pigtails to help identify original 'mutineers of H.M.S. Bounty' Natural Heritage: Fate of turtles, tortoises affected more by habitat than temperature Rainforests: Logged rainforests can be an 'ark' for mammals, extensive study shows