A Canadian nuclear scientist who has not been seen for more than a month has simply vanished, leaving "absolutely no trace at all," police say. Lachlan Cranswick, 41, a physicist from the Chalk River Laboratories nuclear facility in Ottawa, was last seen on Jan. 18, when he left his job and boarded a bus to Deep River, his hometown along the Ottawa River with a population of roughly 4,300. Later that day, or possibly the next morning, Cranswick took out the garbage -- and the single man described as a meticulous loner has not been seen since.