U.S.

In this Jan. 13, 2014 photo, the Los Angeles-class attack submarine USS Scranton returns to Naval Station Norfolk, Va., from a regularly scheduled deployment. Scientists at the Naval Submarine Medical Research Laboratory in Groton, Conn., concluded submarine sailors, who traditionally begin a new workday every 18 hours, show less fatigue on a 24-hour schedule. The first submarine to try the new schedule on a full deployment was the Scranton, led by Cmdr. Seth Burton, who said he found that the more consistent sleep pattern made up for any effects from working slightly longer shifts. (AP Photo/U.S. Navy photo, Shannon D. Barnwell)

View gallery

500 photos

National news events

View Comments