First, I would like to thank my advisors Prof. Gabriel Ulyssea and Prof. Gustavo Gonzaga for their exquisite guidance and rich contribution to this research. I am also extremely grateful for their patience and understanding, without which I would not have finished this work. Then, I wish to thank all the jury members Prof. Renata Del Tedesco Narita and Prof. Juliano Junqueira Assunção for accepting the invite to be in the Examination Committee. I would also like to thank my family and my colleagues in PUC-Rio, who made the entire process much more joyful. Finally, I wish to especially thank my beloved parents, Antonio and Marlene, for their lifelong dedication and sacrifice to raise me. They are true role models whose deeds I will never forget.