1. School of Public Health, University of Alberta, Edmonton, AB T6G 2R3, Canada
2. Balsillie School of International Affairs, Laurier University, Waterloo, ON N2L 6C2, Canada
3. University of the Western Cape, Cape Town 7535, South Africa
4. Department of Geography, Population and Environmental Studies, University of Nairobi, Nairobi P.O. Box 30197-00100, Kenya