"Dolç àngel" de Màrius Torres: un assaig d'anàlisi mètrica

Estudi descriptiu de la mètrica i la rítmica del poema "Dolç àngel" de Màrius Torres, partint d'un element formal recurrent en la seva poesia: les petites però constants transgressions en la versificaci

Error estimates for an operator-splitting method for incompressible flows

In this paper we provide an error analysis of a fractional-step method for the numerical solution of the incompressible Navier–Stokes equations. Under mild regularity assumptions on the continuous solution, we obtain first order error estimates in the time step size, both for the intermediate and the end-of-step velocities of the method; we also give some error estimates for the pressure solution

Analysis of a pressure-stabilized finite element approximation of the stationary Navier-Stokes equations

The purpose of this paper is to analyze a finite element approximation of the stationary Navier-Stokes equations that allows the use of equal velocity-pressure interpolation. The idea is to introduce as unknown of the discrete problem the projection of the pressure gradient (multiplied by suitable algorithmic parameters) onto the space of continuous vector fields. The difference between these two vectors (pressure gradient and projection) is introduced in the continuity equation. The resulting formulation is shown to be stable and optimally convergent, both in a norm associated to the problem and in the L2 norm for both velocities and pressure. This is proved first for the Stokes problem, and then it is extended to the nonlinear case. All the analysis relies on an inf-sup condition that is much weaker than for the standard Galerkin approximation, in spite of the fact that the present method is only a minor modification of this

A finite element formulation for Stokes proble allowing equal velocity-pressure interpolation

In this paper we study a variational formulation of the Stokes problem that accommodates the use of equal velocity-pressure finite element interpolations. The motivation of this method relies on the analysis of a class of fractional-step methods for the Navier-Stokes equations for which it is known that equal interpolations yield good numerical results. The reason for this turns out to be the difference between two discrete Laplacian operators computed in a different manner. The formulation of the Stokes problem considered here aims to reproduce this effect. From the analysis of the finite element approximation of the problem we obtain stability and optimal error estimates using velocity-pressure interpolations satisfying of the standard formulation. In particular, this condition is fulfilled by the most common equal order interpolations

Stabilized finite element method for the transient Navier–Stokes equations based on a pressure gradient projection

In this paper we present a stabilized finite element formulation for the transient incompressible Navier–Stokes equations. The main idea is to introduce as a new unknown of the problem the projection of the pressure gradient onto the velocity space and to add to the incompresibility equation the difference between the Laplacian of the pressure and the divergence of this new vector field. This leads to a pressure stabilization effect that allows the use of equal interpolation for both velocities and pressures. In the case of the transient equations, we consider the possibility of treating the pressure gradient projection either implicitly or explicity. In the first case, the number of unknowns of the problem is substantially increased with respect to the standard Galerkin formulation. Nevertheless, iterative techniques may be used in order to uncouple the calculation of the pressure gradient projection from the rest of unknowns (velocity and pressure). When this vector field is treated explicitly, the increment of computational cost of the stabilized formulation with respect to the Galerkin method is very low. We provide a stability estimate for the case of the simple backward Euler time integration scheme for both the implicit and the explicit treatment of the pressure gradient projection

A finite element formulation for Stokes proble allowing equal velocity-pressure interpolation

In this paper we study a variational formulation of the Stokes problem that accommodates the use of equal velocity-pressure finite element interpolations. The motivation of this method relies on the analysis of a class of fractional-step methods for the Navier-Stokes equations for which it is known that equal interpolations yield good numerical results. The reason for this turns out to be the difference between two discrete Laplacian operators computed in a different manner. The formulation of the Stokes problem considered here aims to reproduce this effect. From the analysis of the finite element approximation of the problem we obtain stability and optimal error estimates using velocity-pressure interpolations satisfying of the standard formulation. In particular, this condition is fulfilled by the most common equal order interpolations

Effects of a positive emotion-based adjuvant psychological therapy in colorectal cancer patients : a pilot study

Objective: To examine the effectiveness of an "Enhancing Positive Emotions Procedure" (EPEP) based on positive psychology and cognitive behavioral therapy in relieving distress at the time of adjuvant chemotherapy treatment in colorectal cancer patients (CRC). It is expected that EPEP will increase quality of life and positive affect in CRC patients during chemotherapy treatment intervention and at 1 month follow-up. Method: A group of 24 CRC patients received the EPEP procedure (intervention group), whereas another group of 20 CRC patients did not receive the EPEP (control group). Quality of life (EORTC-QLQC30), and mood (PANAS) were assessed in three moments: prior to enter the study (T1), at the end of the time required to apply the EPEP (T2, 6 weeks after T1), and, at follow-up (T3, one-month after T2). Patient's assessments of the EPEP (improving in mood states, and significance of the attention received) were assessed with Lickert scales. Results: Insomnia was reduced in the intervention group. Treatment group had better scores on positive affect although there were no significantly differences between groups and over time. There was a trend to better scores at T2 and T3 for the intervention group on global health status, physical, role, and social functioning scales. Patients stated that positive mood was enhanced and that EPEP was an important resource. Conclusions: CRC patients receiving EPEP during chemotherapy believed that this intervention was important. Furthermore, EPEP seems to improve positive affect and quality of life. EPEP has potential benefits, and its implementation to CRC patients should be consideredObjetivo: Examinar la eficacia de un programa basado en la Psicología Positiva y en la terapia cognitivo-conductual (EPEP) para incrementar emociones positivas y reducir malestar en pacientes de cáncer colorrectal (CRC) que reciben quimioterapia adyuvante. Se espera que el EPEP mejore calidad de vida y estados de ánimo durante la quimioterapia y en el seguimiento un mes después. Método: Un grupo de 24 CRC recibió el EPEP (grupo de intervención: GI), y otro grupo de 20 CRC no recibió el EPEP (grupo control: GC). Se evaluaron la calidad de vida (EORTC-QLQC30) y los estados de ánimo (PANAS) en tres momentos: al entrar en el estudio (T1); 6 semanas después, tiempo de aplicación del EPEP (T2), y un mes después del T2 (seguimiento:T3). Las opiniones de los pacientes sobre el EPEP (mejoría del estado de ánimo e importancia de la atención recibida) fueron evaluadas con escalas Lickert. Resultados: El GI mostró mejores puntuaciones en estado de ánimo positivo, aunque sin diferencias significativas con el GC. Las puntuaciones en T2 y T3 tendían a ser mejores en el GI en nivel global de salud, y en las escalas física, social y de rol, El GI redujo el nivel de insomnio. Los pacientes indicaron que el EPEP era importante y mejoraba el estado de ánimo. Conclusiones: Los datos sugieren que el EPEP mejora el estado de ánimo positivo y la calidad de vida, y los pacientes lo consideraron importante y útil. El EPEP es potencialmente beneficioso y debería considerarse la posibilidad de implementarlo en pacientes CR