Carnegie Mellon University has received a huge new pledge to expand its programs. The $265 million gift from William S. Dietrich II is one of the largest in recent years from an individual to a private university, and the largest in the school’s history, officials told the Associated Press. The recession has impacted charitable giving, and the Dietrich pledge may be part of a resurgence. Last week the University of Southern California announced a $6 billion capital campaign, and the Dietrich pledge brought Carnegie Mellon close to meeting its $1 billion campaign…