Affiliation: | 1. Department of Emergency Medicine, Boston University School of Medicine, Boston Medical Center, BCD Building, 800 Harrison Ave., Boston, MA 02118, United States of America;2. Boston University School of Medicine, Instructional Building, 72 E. Concord St., Boston, MA 02118, United States of America;3. Department of Emergency Medicine, Boston Medical Center, BCD Building, 800 Harrison Ave., Boston, MA 02118, United States of America;4. Department of Biostatistics, Boston University School of Public Health, Crosstown Center, 801 Massachusetts Ave., Boston, MA 02118, United States of America |