Jonathan Nguyen conducts his summer science class inside a library, but his students don’t whisper as they twist together DNA models or join an assembly line of peanut butter sandwich-making to learn more about genetic mutations.

Many students say it’s a change from their school-science classes, said Nguyen, a biology and anatomy teacher at Pennsauken High School in Pennsauken, New Jersey. The students “are so gun-shy about things like ‘don’t make a mess’ and ‘don’t make a mistake,’ ” he said, “and in science you’ve got to do both.”

Employees at the American Association for the Advancement of Science (AAAS) and its journal Science today expressed shock and deep sadness at the tragic loss of the gifted science journalist and artist, Constance Holden.

Holden, 68, a veteran journalist and painter affectionately known to friends and colleagues as “Tancy,” apparently had just left the AAAS headquarters building on her bicycle around 6:00 p.m. Monday 12 April when she was struck and killed by a truck providing support for the Nuclear Security Summit taking place in downtown Washington, D.C.