Full Phase-Space Analysis of Particle Beam Transport in the Thermal Wave Model

Within the Thermal Wave Model framework a comparison among Wigner function, Husimi function, and the phase-space distribution given by a particle tracking code is made for a particle beam travelling through a linear lens with small aberrations. The results show that the quantum-like approach seems to be very promising.Comment: 15 pages, plain LaTeX, + 3 uuencoded figures, to be published in Phys. Lett.

Technology replaces culture in microcredit markets: the case of Italian MAGs

We collect data from three Italian microcredit institutions which operate in urban areas by granting individual loans to two categories of wealthless borrowers: single entrepreneurs and organizations (cooperatives and associations).Evidence shows that organizations repay with higher probability and are charged a lower average interest rate than individuals. We use these findings to construct a lending scheme which consists of granting loans provided that borrowers form production teams (i.e. organizations). We consider a microcredit market with adverse selection à la De Meza- Webb and we verify that repayment rate increases, while interest rate falls with respect to individual lending if the above scheme, which we refer to as production team lending, is implemented. Our instrument, like joint liability implemented in rural economies, extracts information from borrowers through a peer selection mechanism but, differently from joint liability, fits to urban contexts where borrowers are less likely to know each other and social sanctions are weak.Microcredit, Urban areas, Production Team Lending, Adverse Selection

Classical and Quantum-like approaches to Charged-Particle Fluids in a Quadrupole

A classical description of the dynamics of a dissipative charged-particle fluid in a quadrupole-like device is developed. It is shown that the set of the classical fluid equations contains the same information as a complex function satisfying a Schrodinger-like equation in which Planck's constant is replaced by the time-varying emittance, which is related to the time-varying temperature of the fluid. The squared modulus and the gradient of the phase of this complex function are proportional to the fluid density and to the current velocity, respectively. Within this framework, the dynamics of an electron bunch in a storage ring in the presence of radiation damping and quantum-excitation is recovered. Furthermore, both standard and generalized (including dissipation) coherent states that may be associated with the classical particle fluids are fully described in terms of the above formalism.Comment: LaTex, to appear in Physica Script

Credit availability in the crisis: which role for the European Investment Bank Group?

In this paper we consider a moral hazard problem between a creditworthy firm which needs funding and a bank. We first study under which conditions the firm does not obtain the loan. We then determine whether and how the intervention of an external financial institution can facilitate the access to credit. In particular, we focus on the European Investment Bank Group (EIBG), which provides (i) specific credit lines to help banks that finance small and medium-sized enterprises (SMEs)and (ii) guarantees for portfolios of SMEs'loans. We show that only during crises the EIBG intervention allows to totally overcome the credit crunch.

Development of a new diagnostic device for extracorporeal shock-wave lithotripsy

Extracorporeal Shock-Wave Lithotripsy (ESWL) is the leading technique for the non-invasive treatment of urinary stones. Thousands of ultrasound shocks are focused on the stones in order to break them into fragments small enough to be passed naturally by the body. The procedure is well established, though the re-treatment rate is around 50%. One of the limits of the procedure is that there is no capability for on-line monitoring of the degree of fragmentation of the stone. The output of the treatments could probably be improved if this facility was made available. The underlying physical mechanisms responsible for the break-up of the stone are still subject to investigation. However both direct stress damage and indirect cavitation erosion seem to be necessary to obtain eliminable fragments. In previous studies, Coleman et al. monitored cavitation in-vivo through the associated acoustic emissions. The objective of this research was to design a new diagnostic device for lithotripsy, exploiting the information carried by these acoustic emissions. After preliminary laboratory experiments some clinical prototypes were developed in collaboration with Precision Acoustic Ltd., UK. The prototypes are currently been tested in the clinic

Intramyocardial hemorrhage: An enigma for cardiac MRI?

Cardiovascular magnetic resonance (CMR) is a useful noninvasive technique for determining the presence of microvascular obstruction (MVO) and intramyocardial hemorrhage (IMH), frequently occurring in patients after reperfused myocardial infarction (MI). MVO, or the so-called no-reflow phenomenon, is associated with adverse ventricular remodeling and a poor prognosis during follow-up. Similarly, IMH is considered a severe damage after revascularization by percutaneous primary coronary intervention (PPCI) or fibrinolysis, which represents a worse prognosis. However, the pathophysiology of IMH is not fully understood and imaging modalities might help to better understand that phenomenon. While, during the past decade, several studies examined the distribution patterns of late gadolinium enhancement with different CMR sequences, the standardized CMR protocol for assessment of IMH is not yet well established. The aim of this review is to evaluate the available literature on this issue, with particular regard to CMR sequences. New techniques, such as positron emission tomography/magnetic resonance imaging (PET/MRI), could be useful tools to explore molecular mechanisms of the myocardial infarction healing process

Matrix Sigma-models for Multi D-brane Dynamics

We describe a dynamical worldsheet origin for the Lagrangian describing the low-energy dynamics of a system of parallel D-branes. We show how matrix-valued collective coordinate fields for the D-branes naturally arise as couplings of a worldsheet sigma-model, and that the quantum dynamics require that these couplings be mutually noncommutative. We show that the low-energy effective action for the sigma-model couplings describes the propagation of an open string in the background of the multiple D-brane configuration, in which all string interactions between the constituent branes are integrated out and the genus expansion is taken into account, with a matrix-valued coupling. The effective field theory is governed by the non-abelian Born-Infeld target space action which leads to the standard one for D-brane field theory.Comment: 14 pages LaTeX, 1 encapsulated postscript figure; uses epsf.te

Bibliography

Abstract