Sapienza University of Rome

About: Sapienza University of Rome is a education organization based out in Rome, Lazio, Italy. It is known for research contribution in the topics: Population & Medicine. The organization has 62002 authors who have published 155468 publications receiving 4397244 citations. The organization is also known as: La Sapienza & Università La Sapienza di Roma.

Path integral approach to birth-death processes on a lattice

Abstract: The Fock space formalism for classical objects first introduced by Doi is cast in a path integral form and applied to general birth-death processes on a lattice. The introduction of suitable auxiliary variables allows one to formulate random walks with memory and irreversible aggregation processes in a Markovian way, which is treatable in this formalism. Existing field theories of such processes are recovered in the continuum limit. Implications of the method for their asymptotic behaviour are briefly discussed.

Fungal infections in cancer patients: an international autopsy survey.

Abstract: In an attempt to estimate the frequency of fungal infections among cancer patients, a survey of autopsy examinations was conducted in multiple institutions in Europe, Japan and Canada. Fungal infections were identified most often in leukemic patients and transplant recipients (25% each). Fifty-eight percent of fungal infections were caused by Candida spp. and 30% by Aspergillus spp. There was considerable variability in the frequency of fungal infections in different countries. Nevertheless, this study clearly demonstrates that fungal infections represent a common complication in cancer patients, especially in patients with leukemia.

Longitudinal Analysis of the Role of Perceived Self-Efficacy for Self-Regulated Learning in Academic Continuance and Achievement.

Abstract: The present study examined the developmental course of perceived efficacy for self-regulated learning and its contribution to academic achievement and likelihood of remaining in school in a sample of 412 Italian students (48% males and 52% females ranging in age from 12 to 22 years). Latent growth curve analysis revealed a progressive decline in self-regulatory efficacy from junior to senior high school, with males experiencing the greater reduction. The lower the decline in self-regulatory efficacy, the higher the high school grades and the greater the likelihood of remaining in high school controlling for socioeconomic status. Reciprocal cross-lagged models revealed that high perceived efficacy for self-regulated learning in junior high school contributed to junior high school grades and self-regulatory efficacy in high school, which partially mediated the relation of junior high grades on high school grades and the likelihood of remaining in school. Socioeconomic status contributed to high school grades only mediationally through junior high grades and to school drop out both directly and mediationally through junior high grades.

Phase Diagram of Patchy Colloids: Towards Empty Liquids

Abstract: We report theoretical and numerical evaluations of the phase diagram for patchy colloidal particles of new generation. We show that the reduction of the number of bonded nearest neighbors offers the possibility of generating liquid states (i.e., states with temperature T lower than the liquid-gas critical temperature) with a vanishing occupied packing fraction (� ), a case which can not be realized with spherically interacting particles. Theoretical results suggest that such reduction is accompanied by an increase of the region of stability of the liquid phase in the (T-� ) plane, possibly favoring the establishment of homogeneous disordered materials at small � , i.e., stable equilibrium gels. The physico-chemical manipulation of colloidal particles is growing at an incredible pace. The large freedom in the control of the interparticle potential has made it possible to design colloidal particles which significantly extend the possibilities offered by atomic systems [1]. An impressive step further is offered by the newly developed techniques to assemble (and produce with significant yield) colloidal molecules, particles decorated on their surface by a predefined number of attractive sticky spots, i.e., particles with specifically designed shapes and interaction sites [2 ‐ 5]. These new particles, thanks to the specificity of the built-in interactions, will be able not only to reproduce molecular systems on the nano and micro scale, but will also show novel collective behaviors. To guide future applications of patchy colloids, to help in designing bottom-up strategies in self-assembly [6 ‐8], and to tackle the issue of interplay between dynamic arrest and crystallization —a hot-topic related, for example, to the possibility of nucleating a colloidal diamond crystal structure for photonic applications [9]—it is crucial to be able to predict the region in the (T-� ) plane in which clustering, phase separation, or even gelation is expected. While design and production of patchy colloids is present-day research, unexpectedly theoretical studies of the physical properties of these systems have a longer history, starting in the eighties in the context of the physics of associated liquids [10 ‐15]. These studies, in the attempt to pin down the essential features of association, modeled molecules as hardcore particles with attractive spots on the surface, a realistic description of the recently created patchy colloidal particles. A thermodynamic perturbation theory (TPT) appropriate for these models was introduced by Wertheim [16] to describe association under the hypothesis that a sticky site on a particle cannot bind simultaneously to two (or more) sites on another particle. Such a condition can be naturally implemented in colloids, due to the relative size of the particle as compared to the range of the sticky interaction. These old studies provide a very valuable starting point for addressing the issue of the phase diagram of this new class of colloids, and, in particular, of the role of the patches number. In this Letter, we study a system of hard-sphere particles with a small number M of identical short-ranged, squarewell attraction sites per particle (sticky spots), distributed on the surface with the same geometry as the recently produced patchy colloidal particles [4]. We identify the number of possible bonds per particle as the key parameter controlling the location of the critical point, as opposed to the fraction of surface covered by attractive patches. We present results of extensive numerical simulations of this model in the grand-canonical ensemble [17] to evaluate the location of the critical point of the system in the (T-� ) plane as a function of M. We complement the simulation results with the evaluation of the region of thermodynamic instability according to the Wertheim theory [16,18,19]. Both theory and simulation confirm that, on decreasing the number of sticky sites, the critical point moves toward ���������������� �