First of all, I would like to express my sincere gratitude to my supervisor Prof. Dr. Christoph Bode. Christoph taught me everything I needed to know about conducting research and presenting one's work in an adequate fashion. He provided valuable feedback and guidance throughout the time I spent at his Chair. Most importantly, I highly appreciate the positive and goal-oriented working atmosphere Christoph established right from the beginning. This fostered productivity and progress regarding my work on the dissertation. Moreover, I could always rely on Christoph regarding issues that extended beyond the usual work-related matters. Special thanks go to my colleagues, especially Michael Westerburg and Sebastian Gehrlein, for valuable discussions, fun lunch breaks, and the distractions from the daily work. In addition, I would like to thank and Helke Naujok and Judith Fuhrmann. Furthermore, I owe a deep debt of gratitude to my parents, Esther and Franz, my fiancée, Danica, and my brother, Janosch. I could always rely on their support and suggestions. Finally, an exciting part of the time I spent working on the dissertation has been made possible by John R. Macdonald and Lynn M. Shore who invited me to Colorado State University (Fort Collins, Colorado). John provided excellent advice on chapter 2 of this dissertation and played a decisive role in making my stay in Fort Collins a great experience.