First-year medical student Michelle Gentile assists her classmate Abbie Harts as she performs a pelvic exam on a volunteer at Northwestern University. Joshua Lott/Reuters /Landov hide caption

itoggle caption Joshua Lott/Reuters /Landov

"Timescape" finds words in the news associated with Sept. 11, and weights them according to prominence in a story — not just how often they appear. Gaurav Bradoo hide caption

itoggle caption Gaurav Bradoo