Columbia University’s interim president, Katrina Armstrong, is stepping aside and the co-chair of its board of trustees, Claire Shipman, has been named acting president, the university said in a statement on Friday. Armstrong is returning to lead the university’s Irving Medical Center, Columbia University said, adding: “Board of trustees co-chair Claire Shipman has been appointed acting president, effective immediately, and will serve until the board completes its presidential search.” In announcing the leadership change, David Greenwald, chair of the board of trustees, said: “Katrina has always given her heart and soul to Columbia. We appreciate her service and look forward...