Arizona State Retirement System, Phoenix, will receive the first phase of an asset allocation study by Callan Associates at the June 11 board meeting. The board of the $21.6 billion system will review which asset classes it should consider in this first phase of the study. In the second phase it will consider active vs. passive investments; and in the third phase, internal vs. external investments. Also, the system has refinanced a $15 million mortgage at a fixed rate of 7.37% for Carey Diversified, as part of its $209 million commercial lending program, said Paul Matson, senior investment officer. The mortgage was secured by a 320,000-square-foot corporate facility in Chandler, Ariz., which is leased to Orbital Sciences Corp.