Network Externalities in Developing Economies

This thesis contains three essays on microeconometrics, networks and economic development. In the first two essays I focus on developing country settings (Tanzania and Nepal respectively) to study how rural villagers form their social networks, and how the existence of these informal links impacts their welfare. The third essay focuses on the international trade of arms to investigate whether the political orientation of government in power makes any difference to arms export policy.

Accretion disk winds in active galactic nuclei: an X-ray view

This Thesis focuses on the X-ray study of the inner regions of Active Galactic Nuclei, in particular on the formation of high velocity winds by the accretion disk itself. Constraining AGN winds physical parameters is of paramount importance both for understanding the physics of the accretion/ejection flow onto supermassive black holes, and for quantifying the amount of feedback between the SMBH and its environment across the cosmic time. The sources selected for the present study are BAL, mini-BAL, and NAL QSOs, known to host high-velocity winds associated to the AGN nuclear regions. Observationally, a three-fold strategy has been adopted: - substantial samples of distant sources have been analyzed through spectral, photometric, and statistical techniques, to gain insights into their mean properties as a population; - a moderately sized sample of bright sources has been studied through detailed X-ray spectral analysis, to give a first flavor of the general spectral properties of these sources, also from a temporally resolved point of view; - the best nearby candidate has been thoroughly studied using the most sophisticated spectral analysis techniques applied to a large dataset with a high S/N ratio, to understand the details of the physics of its accretion/ejection flow. There are three main channels through which this Thesis has been developed: - [Archival Studies]: the XMM-Newton public archival data has been extensively used to analyze both a large sample of distant BAL QSOs, and several individual bright sources, either BAL, mini-BAL, or NAL QSOs. - [New Observational Campaign]: I proposed and was awarded with new X-ray pointings of the mini-BAL QSOs PG 1126-041 and PG 1351+640 during the XMM-Newton AO-7 and AO-8. These produced the biggest X-ray observational campaign ever made on a mini-BAL QSO (PG 1126-041), including the longest exposure so far. Thanks to the exceptional dataset, a whealth of informations have been obtained on both the intrinsic continuum and on the complex reprocessing media that happen to be in the inner regions of this AGN. Furthermore, the temporally resolved X-ray spectral analysis field has been finally opened for mini-BAL QSOs. - [Theoretical Studies]: some issues about the connection between theories and observations of AGN accretion disk winds have been investigated, through theoretical arguments and synthetic absorption line profiles studies.

Oltre il limite invalicabile. Procedure, piani, progetti sostenibili per le aree militari dismissibili di Piacenza

The research project concerns the restoration of military real estate, starting from the procedures in progress in Italy related to dismission, with particular emphasis for Piacenza and the case study of Caserme Bixio and Nicolai (Comparto Nord/San Sisto-Cittadella). The work is aimed at defining the relationship between urban planning and rehabilitation of dismissed military areas, in order to create a synergic effort capable to face the transformation of these sites and their integration into the urban tissue. The results obtained from the various recordings performed in Italy and in USA during the preparation of this thesis may help to find a new possible scenario for the Comparto Nord and its historic buildings.

Utilizzo dell'esame dermoscopico nella valutazione clinica e nel follow up dei nevi melanocitici in sede acrale dell'età pediatrica: studio retrospettivo osservazionale

La dermoscopia, metodica non invasiva, di pratico utilizzo e a basso costo si è affermata negli ultimi anni come valido strumento per la diagnosi e il follow up delle lesioni cutanee pigmentate e non pigmentate. La presente ricerca è stata incentrata sullo studio dermoscopico dei nevi melanocitici a localizzazione palmo-plantare, acquisiti e congeniti, in età pediatrica: a questo scopo sono state analizzate le immagini dei nevi melanocitici acrali nei pazienti visitati c/o l’ambulatorio di Dermatologia Pediatrica del Policlinico Sant’Orsola Malpighi dal 2004 al 2011 per definire i principali pattern dermoscopici rilevati ed i cambiamenti osservati durante il follow up videodermatoscopico. Nella nostra casistica di immagini dermoscopiche pediatriche abbiamo notato un cambiamento rilevante (inteso come ogni modificazione rilevata tra il pattern demoscopico osservato al baseline e i successivi follow up) nell’88,6% dei pazienti ed in particolare abbiamo osservato come in un’alta percentuale di pazienti (80%), si sia verificato un vero e proprio impallidimento del nevo melanocitico e in un paziente è stata evidenziata totale regressione dopo un periodo di tempo di 36 mesi. E’ stato interessante notare come l’impallidimento della lesione melanocitaria si sia verificata per lo più in sedi sottoposte ad una sollecitazione meccanica cronica, come la pianta del piede e le dita (di mani e piedi), facendoci ipotizzare un ruolo del traumatismo cronico nelle modificazioni che avvengono nelle neoformazioni melanocitarie dei bambini in questa sede.

L’iconografia dell’imperatore alato nel contesto della teologia politica bizantina

La presente ricerca di dottorato si propone di esaminare l’evoluzione della teologia politica bizantina e dei suoi riflessi nella propaganda imperiale nel periodo compreso tra il XIII e il XIV secolo, attraverso lo studio delle manifestazioni dell'ideologia nell'iconografia e nella numismatica del periodo in esame. L'intreccio interdisciplinare di questi ambiti di ricerca, iconografia e numismatica - con una metodologia innovativa, i cui risultati si profilano estremamente proficui - permette di comprendere i caratteri concreti, ma forse più reconditi, del realizzarsi dell'ideologia politica e della propaganda imperiale nell'impero bizantino ormai ridotto ad una costellazione di potentati particolari di estensione limitata. Il tema specifico di questo studio ha come oggetto alcune iconografie ritenute inedite, o meno tradizionali, nel panorama numismatico bizantino, emesse, in particolare, dalla zecca di Tessalonica tra XIII e XIV secolo, che vengono qui esaminate in funzione dell’evoluzione della rappresentazione imperiale. Tra di esse emerge l’inedita iconografia dell’imperatore pteroforo per la sua valenza di interscambiabilità semantica con l’immagine arcangelica. Lo studio si è proposto l’obiettivo principale di rintracciare elementi iconologici quanto più possibile comuni tra tutti i soggetti iconografici presi in esame, vagliando il substrato ideologico e propagandistico sotteso alla valenza iconologica per ogni tipologia numismatica.

The Universe 10 Billion years ago: Morphologies, Star-formation rates and Galactic-scale winds in z ∼ 2 Galaxies

This thesis is devoted to the study of the properties of high-redsfhit galaxies in the epoch 1 < z < 3, when a substantial fraction of galaxy mass was assembled, and when the evolution of the star-formation rate density peaked. Following a multi-perspective approach and using the most recent and high-quality data available (spectra, photometry and imaging), the morphologies and the star-formation properties of high-redsfhit galaxies were investigated. Through an accurate morphological analyses, the built up of the Hubble sequence was placed around z ~ 2.5. High-redshift galaxies appear, in general, much more irregular and asymmetric than local ones. Moreover, the occurrence of morphological k-­correction is less pronounced than in the local Universe. Different star-formation rate indicators were also studied. The comparison of ultra-violet and optical based estimates, with the values derived from infra-red luminosity showed that the traditional way of addressing the dust obscuration is problematic, at high-redshifts, and new models of dust geometry and composition are required. Finally, by means of stacking techniques applied to rest-frame ultra-violet spectra of star-forming galaxies at z~2, the warm phase of galactic-scale outflows was studied. Evidence was found of escaping gas at velocities of ~ 100 km/s. Studying the correlation of inter-­stellar absorption lines equivalent widths with galaxy physical properties, the intensity of the outflow-related spectral features was proven to depend strongly on a combination of the velocity dispersion of the gas and its geometry.

Generation and characterization of mouse models of Small cell lung cancer and Basal cell carcinoma for the preclinical evaluation of new therapies

Background. Human small cell lung cancer (SCLC) accounting for approximately 15-20% of all lung cancers, is an aggressive tumor with high propensity for early regional and distant metastases. Although the initial tumor rate response to chemotherapy is very high, SCLC relapses after approximately 4 months in ED and 12 months in LD. Basal cell carcinoma (BCC) is the most prevalent cancer in the western world, and its incidence is increasing worldwide. This type of cancer rarely metastasizes and the death rate is extraordinary low. Surgery is curative for most of the patients, but for those that develop locally advanced or metastatic BCC there is currently no effective treatment. Both types of cancer have been deeply investigated and genetic alterations, MYCN amplification (MA) among the most interesting, have been found. These could become targets of new pharmacological therapies. Procedures. We created and characterized novel BLI xenograft orthotopic mouse models of SCLC to evaluate the tumor onset and progression and the efficacy of new pharmacological strategies. We compared an in vitro model with a transgenic mouse model of BCC, to investigate and delineate the canonical HH signalling pathway and its connections with other molecular pathways. Results and conclusions. The orthotopic models showed latency and progression patterns similar to human disease. Chemotherapy treatments improved survival rates and validated the in vivo model. The presence of MA and overexpression were confirmed in each model and we tested the efficacy of a new MYCN inhibitor in vitro. Preliminar data of BCC models highlighted Hedgehog pathway role and underlined the importance of both in vitro and in vivo strategies to achieve a better understanding of the pathology and to evaluate the applicability of new therapeutic compounds