1 The Mathematical Biosciences Institute, The Ohio State University, Columbus, OH 43210, USA; Biostatistics Division, College of Public Health, The Ohio State University, Columbus, OH 43210, USA.
2 Department of Mathematics, University of Dayton, Dayton, OH, USA.
3 School of Mathematical Sciences, University of Nottingham, Nottingham, UK.
4 Department of Mathematics, The Ohio State University, Columbus, OH 43210, USA.
5 Biostatistics Division, College of Public Health, The Ohio State University, Columbus, OH 43210, USA; Department of Mathematics, The Ohio State University, Columbus, OH 43210, USA.
6 Biostatistics Division, College of Public Health, The Ohio State University, Columbus, OH 43210, USA. Electronic address: kenah.1@osu.edu.