1. Department of Physiological Sciences, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078, USA
2. Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843-4474, USA
3. K2 Solutions Inc., 369 Currie Road, Jackson Springs, NC 27281, USA
4. Department of Statistics, Oklahoma State University, Stillwater, OK 74078, USA