I would like to thank my supervisors Claudia Bauzer Medeiros at Unicamp and Yolanda Gil at the University of Southern California, for their guidance and encouragement during all this time. I will take their advices with me for the rest of my life.I owe a special thank you to my wife Flávia, who was by my side and supported me along the way, even when we were in different countries.I am grateful to my parents, who always supported my studies. My family and relatives made every moment very enjoyable in each visit or each time I went home.I also would like to thank my first supervisor, Hendrik Teixeira Macedo, who introduced me to Science during my undergraduate studies, and again as my supervisor in my Master's degree.