On It\^{o}'s formula for elliptic diffusion processes

Bardina and Jolis [Stochastic process. Appl. 69 (1997) 83--109] prove an extension of It\^{o}'s formula for $F(X_t,t)$, where $F(x,t)$ has a locally square-integrable derivative in $x$ that satisfies a mild continuity condition in $t$ and $X$ is a one-dimensional diffusion process such that the law of $X_t$ has a density satisfying certain properties. This formula was expressed using quadratic covariation. Following the ideas of Eisenbaum [Potential Anal. 13 (2000) 303--328] concerning Brownian motion, we show that one can re-express this formula using integration over space and time with respect to local times in place of quadratic covariation. We also show that when the function $F$ has a locally integrable derivative in $t$, we can avoid the mild continuity condition in $t$ for the derivative of $F$ in $x$.Comment: Published at http://dx.doi.org/10.3150/07-BEJ6049 in the Bernoulli (http://isi.cbs.nl/bernoulli/) by the International Statistical Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm

Stochastic epidemic SEIRS models with a constant latency period

In this paper we consider the stability of a class of deterministic and stochastic SEIRS epidemic models with delay. Indeed, we assume that the transmission rate could be stochastic and the presence of a latency period of $r$ consecutive days, where $r$ is a fixed positive integer, in the "exposed" individuals class E. Studying the eigenvalues of the linearized system, we obtain conditions for the stability of the free disease equilibrium, in both the cases of the deterministic model with and without delay. In this latter case, we also get conditions for the stability of the coexistence equilibrium. In the stochastic case we are able to derive a concentration result for the random fluctuations and then, using the Lyapunov method, that under suitable assumptions the free disease equilibrium is still stable

High resolution DFB laser tuning for optical spectrum analysis in access networks

The project revolves around the development of a low-cost, high-performance Optical Spectrum Analyzer (OSA) for Passive Optical Networks (PON). From the study of the mathematical model of the laser used for the sweeping of the optical networks bandwidth, to the experimental section where different parameters of the laser, mainly current and temperature, are tuned simultaneously and combined along with their strengths to obtain a fast and broad sweep. At last, the results of the proposed equalization method are assessed to confirm the viability of such a method

Una anàlisi sociològica de l'atenció a la diversitat

El artículo presenta los resultados de un estudio realizado en cuatro escuelas secundarias de una localidad catalana durante el periodo 1996-1998. El estudio ha aplicado la teoría del dispositivo pedagógico de Basil Bernstein al análisis del tratamiento de la diversidad en la Educación Secundaria Obligatoria. Para elfo ha investigado los procesos de recontextualización oficial y pedagógica de este principio educativo, así como su influencia sobre las prácticas docentes en el aula. Las hipótesis sugieren que este proceso de recontextualización ha inducido a las escuelas a individualizar, normalizar y reprofesionalizar la noción de diversidad. Los discursos oficial, pedagógico y docente reflejan los dos primeros efectos, pero el profesorado se ha desentendido bastante de las propuestas oficiales y pedagógicas dirigidas a la reprofesionalización.Cet article présente les résultats d'une étude réalisée auprés de quatre écoles secondaires d'une loca lité catalane pendant la période alfant de 1996 á 1998. Cette étude a appliqué la théorie du dispositif pédagogique de Basil Bernstein á f'analyse du traitement de la diversité au niveau de f'Éducation Secondaire Obligatoire. A cette fin, on a étudié les processus de recontextualisation officielfe et pédagogique de ce éloigné principe éducatif ainsi que son influence sur les pratiques d'enseignement dans la salfe de c/asse. Les hypothéses suggérent que ce processus de recontextualisation a mené les écoles á individualiser, normaliser et «reprofessionnaliser » la notion de diversité. Les discours officiel, pédagogique et d'enseignement reflétent les deux premiers effets mais le professorat s'estassez des propositions officielfes et pédagogiques dirigées á la «reprofessionnalisation».The article reports the findings from a study carried out in four secondary schools in a Catalan town between 1996 and 1998. Basi/Bernstein's «pedagogic device » pro vides the framework for an analysis of the way in which educational diversity has been included among the principies of the new system of compulsory secondary education in Spain. The research focuses on how «diversity» underwent both an official and a pedagogic recontextualisation, as welf as how these processes impinged upon classroom practices. The analysis tests the hypothesis that schoo/s have eventually individualised and normalised «educational diversity» in line with both official and pedagogic discourses. However, although these discourses proposed that teachers should also redefine their profession by incorporating diversity-related skilfs, it is apparent that they have failed to do so

L'avantguarda artística a Vilanova: presència i influència

L’article pretén donar algunes referències de l’avantguarda artística des de Vilanova. S’analitzen els noms dels principals pintors i escultors vinculats a Vilanova, per naixement o per haver-hi treballat amb regularitat, que es poden considerar influïts per l’avantguardisme o que s’hi poden considerat adscrits: Joaquim Mir, Rafael Sala, Enric C. Ricart, en els inicis del concepte d’avantguarda; Armand Cardona Torrandell, Òscar Estruga i alguns altres més joves, en la represa de l’avantguarda després de 1957. També es parla d’obres d’escultura i de pintura d’avantguarda que es poden veure en lloc públics de Vilanova, d’obres d’arquitectura que hi estan ubicades i també d’algunes manifestacions d’altres arts diferents de les esmentades, com ara la música, la dansa o la literatura. L’autor remarca que es tracta d’una aproximació al tema, susceptible de debat i d’aportacions noves