Postdoctoral candidates should provide three letters of reference and contact Nathan Kucera if planning to visit The New York/N ew Haven area.     Nathan Kucera   C/O Aspiring Post Doc   Yale University School of Medicine   Department of Pharmacology   Sterling Hall of Medicine   333 Cedar Street, B-295   P.O. Box 208066   New Haven, CT 06520-8066   Phone: (203) 785-7345   Fax: (203) 785-3879