Ravi S Sharma, for his encouragement, guidance, and support, at every stage of this study without which the research could not have been completed. I would also like to convey my heartfelt gratitude to my acting supervisor Professor Charles Salmon, as well as the oral examination panel members Associate Professor Na Jin Cheon and Assistant Professor Natalie Pang who also doubled up as my mentors and saw my thesis through to its completion.My heartfelt thanks also go to my father, Dr. Felix Paul, who, despite his on-going battle with cancer, helped proofread my thesis and journal papers and make valuable suggestions.My sincere thanks are also due to my husband, Thomas, who has been a pillar of support throughout. I am also thankful to the rest of my family for their concern and endless encouragement.