1. a Department Physics, University of Puerto Rico Mayagüez, Mayagüez, Puerto Rico
2. b Department of Geography, University of Zululand, KwaDlangezwa, Empangeni, South Africa
3. c Department of Nursing Science, University of Zululand, KwaDlangezwa, Empangeni, South Africa
4. d Nursing Division, University of KwaZulu-Natal, Durban, South Africa