1. Department of Applied Social Sciences, The Hong Kong Polytechnic University, Hong Kong
2. Public Policy Research Institute, The Hong Kong Polytechnic University, Hong Kong
3. Kiang Wu Nursing College of Macau, Macau, China
4. Department of Sociology, East China Normal University, Shanghai 200241, China
5. Division of Adolescent Medicine, Department of Pediatrics, Kentucky Children's Hospital, University of Kentucky College of Medicine, Lexington, KY 40506-9983, USA