The welcome mat is being pulled out from under Mark Thompson, the incoming chief executive of The New York Times, by Margaret Sullivan, the newspaper's ombudsman. In a post on the newspaper's blog on Tuesday, Sullivan called on the Times's journalists to investigate Thompson's knowledge of the late host Jimmy Savile's behavior with teenage girls when Thompson was director general of the BBC and his involvement -- if any -- in the cancellation of a report on the BBC's Nightline about Savile's alleged misconduct. In an interview with the