1. Physics Department, McGill University, Montréal, Canada.
2. Department of Physics and Astronomy, University of California, Los Angeles, California.
3. Present address: Gemini Observatory, Hilo, Hawaii.
4. Department of Physics, Case Western Reserve University, Cleveland, Ohio.
5. Present address: Kent State University, Ashtabula Campus, Ashtabula, Ohio.
6. Department of Physics and Astronomy, Barnard College, Columbia University, New York, New York.
7. Department of Physics, University of Alberta, Edmonton, and TRIUMF, Vancouver, Canada.
8. Present address: Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, Arizona.
9. Present address: Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada.
10. Present address: Sander Geophysics Ltd., Ottawa, Canada.
11. Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, California.