1. Department of Statistics; Temple University; Philadelphia PA 19122 U.S.A.
2. Department of Statistics; The Pennsylvania State University; University Park PA 16802-2111 U.S.A.
3. Center for Statistical Genetics; The Pennsylvania State University; Hershey PA 17033 U.S.A.
4. Computer, Information Science & Engineering; University of Florida; Gainesville FL 32611 U.S.A.