Karl Polen was elected chairman of the $17 billion Arizona State Retirement System board. He replaced Alan Maguire, who was not reappointed to the board by Gov. Janet Napolitano. Mr. Polen already is a board member. Ms. Napolitano also appointed Keith Meredith, Lawrence Trachtenberg and Steven Zeman to the nine-member board, filling the vacancies left by Mr. Maguire as well as Bonnie Gonzales and Ray Rottas, who also were not reappointed. The board votes to determine a new chairman, said David Cannella, communications and media relations manager.