1. Odum School of Ecology; University of Georgia; Athens; GA; 30602; USA
2. Department of Mathematics; University of Georgia; Athens; GA; 30602; USA
3. Department of Anthropology; University of Illinois at Urbana-Champaign; Urbana; IL; 61801; USA
4. Department of Management; University of Kentucky; Lexington; KY; 40506; USA