Abstract : I offer special and heartfelt thanks to my professor, Dr. John Weidman, whose guidance and encouragement throughout the dissertation process was essential. I would like to thank the members of my committee, Dr. Tony Eichelberger, Dr. John Mosley, and Dr. Hidenor Yamatani for their generous advice, support, and guidance. I am deeply indebted to each of the committee members for their assistance and contribution of time. I especially would like to acknowledge a close friend, Dr. Cynthia Liefeld, who shared with me many strong feelings and whose input in proofreading, corrections and shared ideas was critical to this dissertation. I will always be grateful for her counsel and assistance in developing this topic. I am grateful to my best friend, Khalid Al-Seghayer, for his helpful smart ideas as well as his continuing support and encouragement over the four years of course work. I feel the most profound appreciation for his mentorship, listening to me describe my work during this time. Without these two friends, I don't know if I would have finished this work. In addition, I would like to thank Dr. Elaine Rubinstein for her statistical consultation. I would also like to thank all of my College of Health Sciences colleagues and students and the Ministry of Health staff. I also want to express my gratitude to all my friends in Bahrain and Pittsburgh, especially Dr. Mohammed Ali Mansoor, Dr. Fariba Al-Darazi, Mr. Jawad Shehaab and Candy Weller, who displayed their confidence in my ability to succeed. I am grateful to my family who encouraged and supported my educational goals. I express my heart-felt appreciation and love to them. I dedicate this dissertation to the memory of my Father who by his example raised me to be strong in character and spirit, and to live my life with honesty and ambition. To my Mother I am grateful for her patience, support, and encouragement. To my aunt Tieba Al-Banna, to my sisters, brothers, nieces and nephews- they have my gratitude and love. I am especially indebted to my sister Ahlam and her family, especially my brother in-law Abdulla Rahimi and my nephew Mohamed Al-Sharf. I am blessed with many wonderful people in my life who have helped and encouraged me in numerous ways during my journey. I am unable to thank then all by name but wish them well.