1. US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD;
2. Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia, PA;
3. Division of Epidemiology and Biostatistics, University of Arizona Mel and Enid Zuckerman College of Public Health, Tucson, AZ; and
4. Department of Computer Science, New Jersey Institute of Technology, Newark, NJ