The board late last week unexpectedly elevated one of its two co-chairs, Claire Shipman, as acting president.  While not unheard of, experts said it is unusual for a trustee to take the helm of a

Columbia University's interim president, Katrina Armstrong, has stepped down, the college said, at a time when the New York-based institution is facing intense pressure from both the government and rights advocates over how it responds to last year's Gaza protests.