Acknowledgements

I'm deeply thankful to my parents for their infinite patience, enthusiasm, and support throughout my life. Moreover, I'm thankful to the rest of my family, in particular to my grandparents, since they have always encouraged me to do better in my life with the Latin expressions "Ad maiora" and "Per aspera ad astra".

Finally, a huge thanks to all the special people around me whom I love, in particular to my girlfriend; I'm grateful for all of your help in everything. I do love you.