1. Postdoctoral Fellow, Rehabilitation Sciences Academic Division and Research Center; The University of Texas Medical Branch; Galveston TX USA
2. Postdoctoral Trainee, Sealy Center on Aging; The University of Texas Medical Branch; Galveston TX USA
3. Professor of Medicine, Division of General Medicine; University of Michigan; Ann Arbor MI USA
4. Senior Fellow, Sealy Center on Aging, Professor, Preventive Medicine & Community Health, Director, WHO/PAHO Collaborating Center on Aging and Health; The University of Texas Medical Branch; Galveston TX USA