1. Department of Biostatistics; University of North Carolina Chapel Hill; Chapel Hill NC
2. Division of General Medicine and Clinical Epidemiology; University of North Carolina Chapel Hill; Chapel Hill NC
3. School of Medicine; University of North Carolina Chapel Hill; Chapel Hill NC
4. Department of Anesthesiology; University of North Carolina Chapel Hill; Chapel Hill NC
5. College of Dentistry; University of Florida; Gainesville FL
6. Department of Family Medicine; University of North Carolina Chapel Hill; Chapel Hill NC
7. Department of Emergency Medicine; University of North Carolina Chapel Hill; Chapel Hill NC