Robert Lefkowitz has left Delaware Investment Advisers in Philadelphia, where he was a high-grade trader, to join Deutsche Asset Management in New York as a high-grade industrials trader and v.p. sector manager. Lefkowitz says he made the move because he wanted to return to New York where he grew up and started his career. He will report to John Ryan, managing director. Ryan did not return calls. Ryan Brist, who manages Delaware Investment Advisers' core and core plus institutional assets, declined comment about his plans regarding a possible replacement for Lefkowitz.