Institution: | Biomathematics Program, Department of Statistics, North Carolina State University, Raleigh, NC 27695–8203, U.S.A.; Department of Mathematics, University of British Columbia, 1984 Mathematics Road, Vancouver, British Columbia V6T 1Z2, Canada; Environmental Studies Department, 339 Natural Sciences 2, University of California, Santa Cruz, CA 95064, U.S.A. |