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The paper analyzes how (production and financial) inter-firm networks can affect firms’ default probabilities and observed default rates. A simple theoretical model of shock transfer is built to investigate some stylized facts on how firm-idiosyncratic shocks are allocated in the network, and how this allocation changes firm default probabilities. The model shows that the network works as a perfect “risk-pooling” mechanism, when it is both strongly connected and symmetric. But the “risk-sharing” does not necessarily reduce default rates, unless the shock firms face is lower on average than their financial capacity. Conceived as cases of symmetric inter-firm networks, industrial districts might have a comparative disadvantage in front of heavy crises.

The paper investigates the role spatial agglomeration has in affecting firm mortality of industries. In particular, the role of variety and specialization is addressed, along with the extent to which industrial clusters can be retained industrial districts. Empirical evidence is provided for a large panel of Italian provinces and manufacturing sectors, over the period 1995-2007. Urbanization economies, rather than localization ones, significantly diminish firm mortality of industries at the local level. The same holds true for industrial variety, even far from the specialization core. Industrial districts, instead, are neither safe nor dangerous places for firms, unless variety is controlled for. Preliminary evidence is also provided by the serial and spatial autocorrelation of firm’ death and start-up rates.

The design, synthesis, and antibacterial activity of 4-alkyliden-azetidin-2-ones as new antimicrobial agents against multidrug-resistant pathogens is reported. 4-Alkyliden-azetidin-2-ones were easily obtained using an original protocol starting from 4-acetoxy-azetidinones and diazoesters. Parent compounds were further elaborated to obtain a small library of 4-alkylidene derivatives. A molecular modeling approach using GRID descriptors based on the concept of VRS identified attractive drug candidates and contributed to the rationalization of functional group effects in QSARs. The in vitro antibacterial activity of the new agents was evaluated against 43 recent clinical isolates of antibiotic-susceptible and -resistant Gram-positive and Gram-negative pathogens by determining their minimum inhibitory concentrations (MICs). The most active compound showed MIC values ranging from 0.25 to 32 mg/L against some of the bacterial species tested. Interestingly, some compounds demonstrated similar activity against methicillin-susceptible and -resistant strains of Staphylococcus aureus suggesting possible alternative mechanisms of action of these agents, supported by citotoxicity and preliminary scanning electron microscopy studies.

The paper presents a comprehensive analysis of the process of high tech firms clustering from a theoretical and empirical perspective. The theoritical analysis shows the effects of geographical and agglomeration factor on firms location decisions and demonstrates that critical mass and carrying capacity are crucial phenomena in the life cycle of the cluster. The empirical analysis measures the effects of scale versus agglomeration economies and of inter-industry synergy versus inter-cluster competition on the growth path of the cluster

The essay explores the different dimensions of innovation in the service sectors in Italy and highlights the role of technological externalities.

Il saggio discute i problemi di analisi economica dei servizi ed esamina la dinamica dei settori dei servizi nell'economia italiana nel Dopoguerra.