1. Department of Biostatistics & Epidemiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
2. School of Civil Engineering and Environmental Science, University of Oklahoma, Norman, OK 73019, USA
3. Acute Diseases Division, Oklahoma State Department of Health, Oklahoma City, OK 73102, USA
4. Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
5. School of Biological Sciences, University of Oklahoma, Norman, OK 73019, USA
6. Department of Earth and Planetary Sciences, Northwestern University, Evanston, IL 60208, USA