Spring commencement at Clemson University today is being handled in three ceremonies in the Littlejohn Coliseum. Graduates in the College of Architecture, Arts and Humanities and the College of Business and Behavioral Science receive degrees at 9:30 this morning. A second ceremony begins at 2:30 for graduates in the colleges of Agricultural Forestry and Life Science; and Health, Education and Human Development. The third ceremony begins at 6:30 p-m for students in the College of Engineering and Science. Seating is available first-come, first-served. Additional seating will be available on the coliseum’s concourse, where guests can watch on large-screen TVs. All guests should note that backpacks are not allowed. Security measures adopted after 9/11 and most recently, the Boston Marathon bombings, exclude backpacks and any large bags from the list of items allowed. Items allowed but subject to search are purses, diaper bags, seat cushions, binoculars, cameras, video cameras, cell phones, radios, Walkman-type radio/recorders and hand-held TVs.