[1] Univ Washington, Seattle, WA 98195 USA
[2] Harvard Univ, Sch Med, Cambridge, MA 02138 USA
[3] Boston Univ, Boston, MA 02215 USA
[4] MIT, Cambridge, MA 02139 USA
[5] Univ Calif Berkeley, Berkeley, CA 94720 USA
[6] Duke Univ, Durham, NC 27706 USA
[7] CALTECH, Pasadena, CA 91125 USA
[8] Princeton Univ, Princeton, NJ 08544 USA