I dedicate this book to God, in whom I place my faith. Who enlightened me to overcome all obstacles with strength, lightness and tranquillity at the right times. To my beloved husband Rodrigo Bastos, my faithful companion, who always helps me overcome every obstacle with his love, patience, trust and endless support. To my beloved parents, Luzimar Enaura and Joel Pinheiro, for their constant encouragement to study, their valuable and wise words, their understanding and their greatest love. To my sisters, Gabriella and Isabella, for their sincere smiles at key moments and for understanding my absence, even when I was present. To my dear professors, advisors and friends, Dr Carlos Henrique Falcão Tavares and Dr Jerzuí Mendes Tôrres Tomaz. Models of competence, humility and coherence.