Add to ORKGI would like to express my sincere gratitude to my advisor Dr. Tim Penning for WKHFRQWLQXRXVVXSSRUWRIP\PDVWHU¶VVWXG\DQGUHVHDUFK+LVJXLGDQFHKHOSHGPHLQDOO the time of research and writing of my thesis. Besides my advisor, I would like to thank the rest of my thesis committee Dr. Alex Nesterenko and Dr. Paul Lane for their encouragement, insightful comments, and good questions. My sincere and great thanks goes to all my family: my great mother, Halina Abramenka, brother, Vladimir Abramenka, my cousins, Natalia Toropova and Dmitri Toropov, my aunt, Valentina Toropova, and my boyfriend, Ahmed Lachheb. This thesis would not have been possible without their tremendous support.