1. Department of Biostatistics, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
2. School of Mathematics, Institute for Advanced Study, Princeton, NJ, USA
3. Division of Burns, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
4. RTI International, Research Triangle Park, NC, USA
5. Division of Plastic Surgery, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA