1. Department of Statistics, University of Nebraska-Lincoln, Lincoln, Nebraska 68583-0963, United States
2. Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0304, United States
3. Nebraska Center for Integrated Biomolecular Communication, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0304, United States
4. Department of Applied Statistics and Operations Research, Bowling Green State University, Bowling Green, Ohio 43403-0001, United States