for their valuable comments. I would also like to thank Visiting Professor Lida Thomo for supporting and encouraging me during the period of my graduate studies. This dissertation was partly prepared while I was an exchange student at Utrecht University. The hospitality of the Department of Economics, staff and graduate students is highly appreciated. Assistant Professor Claire Economidou deserves special thanks for supervising my Dissertation during my staying in the Netherlands. Her help and interest with respect to my future professional development, is also highly appreciated. Apart from her support with academic and professional matters, she has been close to me as a friend.She taught me how to go through life with less stress and not to get overwhelmed by small things.I would like to thank my office mates and especially Maria Christidou, for tolerating me, especially during the last few months I spent writing my dissertation.At home, the much harder task of tolerating my changes of mood as my work progressed (or regressed) fell upon my fiancé, Grigorios Emvalomatis. Being an economist with special interest in econometrics himself, he did a lot to support me emotionally. He was there to listen and to offer advice and suggestions. For that and for his understanding I am grateful to him.Finally, I would like to thank my mother, who is continuously by my side, supporting me emotionally and financially. Similarly, I wish to thank my parents-in-law for supporting me in a number of ways.