Tag der mündlichen Prüfung: 13.03.2019 II Acknowledgements My sincere thanks go to all my colleagues for the very nice cooperation over the past years. Passionate discussions and a good portion of humor have made working very pleasant. I am very grateful for the fruitful cooperation that and I will miss you. Especially my supervisors, Uwe Mattler, Hannes Rakoczy and Thorsten Albrecht helped me a lot to advance my work with constructive criticism, emotional support and inspiration. I have always found an open ear and the willingness to support me with problems. Thank you very much for your support over the last three years. Of course, I would never have been able to work without the support of the student assistants who accompanied me during my doctorate: Alexander Kraut, Judith Diele, Charlotte Fink, Selin Altiok und Katja Lorenz. Thank you very much for your great cooperation.My thanks also go to my family and friends, who cheered me up in difficult times and without whom life would be half as beautiful. In particular I would like to thank my husband, who is always there for me with help and advice, who believes in me and supports me. I would like to dedicate the last thought to my daughter who made it possible to finish my work in spite of her presence. I am very happy that you are with us.