FREE MARKET ACCESS FOR LDCS UNDER THE EBA INITIATIVE. AN EMPIRICAL ANALYSIS USING THE GRAVITY APPROACH

This paper assesses the effectiveness of the Everything But Arms (EBA) initiative launched by the EU in 2001. It evaluates whether EBA was effective in increasing the exports from LDCs to the EU over the period 1995-2006. After arguing that the impact of trade preferences should be estimated by using disaggregated trade flows rather than aggregated trade, the analysis is carried out by considering five products (cloves, coffee, crustaceans, molluscs and vanilla beans) which meet three selecting criteria related to the export intensity of EBA countries, to the real/actual preferences of EBA and to the intra-year distribution of EU tariffs. Furthermore, the exports share of the 5-selected goods with respect to national exports is never marginal and, in many cases, is higher than 60%. From an econometric perspective, we improve the reliability of results by giving more attention to the econometric setting and to measurement of the preferential treatment. The evidence is mixed and while this limits the possibility to draw a general conclusion about the role of EBA, it supports the decision to work using disaggregated data because the evidence provided allows us to gauge the sector specificities which would be hidden when analysing total trade. Results show a positive impact on the exports of crustaceans and vanilla of the preferential treatment granted by the EU under EBA, whereas the evidence is un-conclusive when considering the other three products.Trade preferences, EBA initiative, gravity model, Panel data

REGIONAL ECONOMIC DIVIDE AND THE ROLE OF TECHNOLOGICAL SPILLOVERS IN ITALY. EVIDENCE FROM MICRODATA

This paper assesses the impact of R&D efforts on production in the North and Centre-South of Italy by using a panel of 1203 manufacturing firms over the period 1998-2003. The estimations are based on a nonlinear translog production function augmented by a measure of R&D spillovers. This measure combines the geographical distance between firms, the technological similarity within each pair of firms and the technical efficiency of each firm. The estimation method takes into account the endogeneity of regressors and the potential sample selection issue regarding firms’ decision to invest in R&D. Results show that the external stock of technology exerts a higher impact in the Centre-South of Italy. Finally, it emerges that R&D capital and R&D spillovers are substitutes for Northern firms and complements for Centre-Southern firms.R&D spillovers, Italian economic divide, translog production function, technical efficiency

Controlling quantum transport through a single molecule

We investigate multi-terminal quantum transport through single monocyclic aromatic annulene molecules, and their derivatives, using the nonequilibrium Green function approach in the self-consistent Hartree-Fock approximation. A new device concept, the Quantum Interference Effect Transistor (QuIET) is proposed, exploiting perfect destructive interference stemming from molecular symmetry, and controlling current flow by introducing decoherence and/or elastic scattering that break the symmetry. This approach overcomes the fundamental problems of power dissipation and environmental sensitivity that beset many nanoscale device proposals.Comment: 4 pages, 5 figure

Le criticità del post, il caso EXPO 2015

A pochissimo tempo dalla chiusura di Expo Milano 2015 vi è ancora un grosso interrogativo su ciò che avverrà nell’area dell’esposizione una volta conclusi i lavori di smantellamento dell’evento. L’incertezza e l’immobilità delle istituzioni, che tanto hanno spinto affinché la manifestazione riuscisse nelle sue fasi iniziali, certamente non contribuiscono a smorzare le perplessità crescenti. Se a quanto detto vengono sommati i numerosi scandali nelle fasi iniziali della manifestazione si può capire come le preoccupazioni per la riqualificazione dell’area Expo siano molte e giustificate. Queste si fondano sulla consapevolezza che il non aver previsto per tempo il destino dell’Esposizione sia stato un errore strategico per lo sviluppo futuro dell'area

Heavily Obscured AGN in High Redshift Luminous Infrared Galaxies

We take advantage of the rich multi-wavelength data available in the Chandra Deep Field South (CDF-S), including the 4 Msec Chandra observations (the deepest X-ray data to date), in order to search for heavily-obscured low-luminosity AGN among infrared-luminous galaxies. In particular, we obtained a stacked rest-frame X-ray spectrum for samples of galaxies binned in terms of their IR luminosity or stellar mass. We detect a significant signal at E~1 to 8 keV, which we interpret as originating from a combination of emission associated with star-formation processes at low energies combined with a heavily-obscured AGN at E>5 keV. We further find that the relative strength of this AGN signal decays with decreasing IR luminosity, indicating a higher AGN fraction for more luminous IR sources. Together, these results strongly suggest the presence of a large number of obscured AGN in IR-luminous galaxies. Using samples binned in terms of stellar mass in the host galaxy, we find a significant excess at E=6-7 keV for sources with M>10^{11} Msun, consistent with a large obscured AGN population in high mass galaxies. In contrast, no strong evidence of AGN activity was found for less-massive galaxies. The integrated intensity at high energies indicates that a significant fraction of the total black hole growth, ~22%, occurs in heavily-obscured systems that are not individually detected in even the deepest X-ray observations. There are also indications that the number of low-luminosity, heavily-obscured AGN does not evolve significantly with redshift, in contrast to the strong evolution seen in higher luminosity sources.Comment: 5 pages, 3 figures in emulateapj format. Accepted by Astrophysical Journal Letter

Riflessioni a margine della didattica

Il testo riassume l'esperienza didattica condotta dall'Autore nell'ambito del Laboratorio di Restauro dei Monumenti, da lui tenuto nell'a.a. 2005-06. Di questa ne sintetizza le linee guida, i contenuti e i risultati finali. Il testo è corredato da una selezione di elaborati grafici prodotti dagli studenti, da fotografie e da due brevi contributi dei docenti dei moduli afferenti al Laboratorio stesso