1. Jianqing Fan is Frederick L. Moore’18 Professor of Finance, Department of Operations Research and Financial Engineering, Princeton University, Princeton, NJ 08544, and Honorary Professor, Department of Statistics, Shanghai University of Finance and Economics, Shanghai, China . Yichao Wu is Assistant Professor, Department of Statistics, North Carolina State University, Raleigh NC 27695 . This research is supported in part by National Science Foundation grant DMS-03-54223 and National Institutes of Health...