USC journalism professor Sue Horton has been named editor in chief of the L.A. Weekly alternative newspaper.The post has been vacant since July, when publisher Michael Sigman and president Gary Horowitz fired Kit Rachlis in a dispute over the editorial direction. A number of the Weekly’s editorial staff then quit in protest, including John Powers, Michael Ventura, Ella Taylor, film editor Steve Erikson, Tom Carson and news editor Ruben Martinez. Horton has been a freelance writer for the Los Angeles Times and California Magazine, focusing on crime, housing, healthy and entertainment. Horton, Sigman and Horowitz were unavailable for comment. The appointment was official as of Tuesday, although the new editor’s start date has not been announced.