The present work is dedicated to all those who have supported me throughout this journey.I would first like to thank my supervisor, Professor Rosa Forte, whose expertise and patience were invaluable in the writing of this dissertation. Your guidance was fundamental to the completion of this work and brought it to a higher level.I want to thank my parents, Fernanda and Fernando, for the encouragement and support they have given me all through my studies. I would like to acknowledge my sister, Joana, for believing in me and for always being there for me when I need her. I would also like to thank my cousins, Sílvia, Isabel and Margarida, for the kind words and motivation.Lastly, I would like to acknowledge my colleagues and friends, who have made this experience so memorable.