ADVANCE FOR MONDAY, APRIL 21, 2014 - In this Thursday, April 17, 2014, photo, University of Massachusetts nursing professor Adrienne Wald, center, helps carry a banner that features a photo of Krystle Campbell, a UMass nursing student who died in the Boston Marathon bombings in 2013, during a tribute walk on a track at the school in Boston. Wald, who has run the Boston Marathon five time, organized a group of her students last year to work as race volunteers on the sweep team, standing with wheelchair runners they expected to be dehydrated or otherwise needing minor medial care. None of her students was injured in the bombing. (AP Photo/Steven Senne)