VATICAN CITY — The pope's top aide said Wednesday that Benedict XVI's reason for canceling a visit to a Rome university was that he did not want to create a pretext for further "unpleasant" protests by professors and students opposed to the religious leader speaking at a secular campus. Anti-pope slogans have appeared on banners and posters around buildings at La Sapienza University, where Benedict was to have spoken on Thursday. A group of professors, mainly from the sciences, wrote to the university rector late last year to object to the pope's visit, depicting Benedict as a religious figure opposed...