Acknowledgments
First of all, I would like to thank Professor Paolo Grigolini, who arose my interests in com- plex system physics through his greatly stimulating discussion some years ago. He was indeed the first person who led me to discover this fascinating branch of physics, and who awoke in me the curiosity to know “how the world works”.
I would also like to express my gratitude to my supervisor Dr. Esteban Moro Egido, for having provided me excellent working conditions, encouragement and guidance throughout this process. I appreciated the way in which he made myself at home in Madrid addressing to me much more as friend than as student. That was a really educational period of my life in many ways.
Thanks are also due to Dr. Riccardo Mannella, who encouraged my work, giving to me many valuable advises for the writing out of my thesis. Moreover his patience with a
“lazzarone” as I am has been unlimited.
On an even deeper layer, I thank my family for having supported me over the years, helping me to pursue my interests.
I also wish to thank all my friends, the good ones even more the wicked ones, such as Marco, Sergio, Alessandro and those who have revealed themselves one of life’s great joys.
Finally, I cannot omit to thank my “Nina”, whose lighthearted smile has been sustaining me each instant of these last months.
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