A Multigrid Optimization Algorithm for the Numerical Solution of Quasilinear Variational Inequalities Involving the pp-Laplacian

In this paper we propose a multigrid optimization algorithm (MG/OPT) for the numerical solution of a class of quasilinear variational inequalities of the second kind. This approach is enabled by the fact that the solution of the variational inequality is given by the minimizer of a nonsmooth energy functional, involving the $p$-Laplace operator. We propose a Huber regularization of the functional and a finite element discretization for the problem. Further, we analyze the regularity of the discretized energy functional, and we are able to prove that its Jacobian is slantly differentiable. This regularity property is useful to analyze the convergence of the MG/OPT algorithm. In fact, we demostrate that the algorithm is globally convergent by using a mean value theorem for semismooth functions. Finally, we apply the MG/OPT algorithm to the numerical simulation of the viscoplastic flow of Bingham, Casson and Herschel-Bulkley fluids in a pipe. Several experiments are carried out to show the efficiency of the proposed algorithm when solving this kind of fluid mechanics problems

Valuation of Debt Indexed to Real Values I. The case of the Argentinean Growth Coupon: a Simple Mode

This paper is the first of a series of works whose aim is trying to provide a framework for the understanding and valuation of debt indexed to real (gener- ally non-tradable) variables. In particular, in the present paper we develop a methodology to analytically value the new GDP-linked Argentinean warrant.

Beyond forgiveness and suicidal behaviour in adolescence: the moderating role of gender

With the development of positive psychology, forgiveness has received increasing attention among psychologists from different social science fields . Empirical evidences have suggested associations between forgiveness and suicidal ideation and behaviours, but moderator’s role of gender has been scarcely studied. The aim of the present study was to test the role of gender as a potential moderating factor in the relationship between forgiveness and suicidal behaviour in adolescence. A total of 586 Spanish adolescents from three different high school centres took part in this study. Their average age was 15.51 (SD= 1.17) and 51.2% were men. We conducted moderation analyses and used age and personality factors as control variables. First, we found negative association between forgiveness and risk suicide. Moreover, results showed that gender moderated the relationship between forgiveness and suicidal ideation. Specifically, males compared to females were found to show significantly higher tendency of suicidal behaviour depending on their level of forgiveness. Thus, males who showed higher scores on forgiveness tend to report lower levels of suicidal behaviour, whereas males who reported lower scores on forgiveness showed greater levels of risk suicide. Our findings suggest that forgiveness may operate as a key buffering factor against suicidal risk underlying the importance of examining gender differences in this association. These findings provide therapeutic targets to reduce risk of suicide in this high-risk group of adolescent males with lower levels of forgiveness. Our results are discussed in terms of the need of using gender perspectives in positive psychology intervention programs.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

New methodology for calculating damage variables evolution in Plastic Damage Model for RC structures

The behavior of reinforced concrete (RC) structures under severe demands, as strong ground motions, is highly complex; this is mainly due to joint operation of concrete and steel, with several coupled failure modes. Furthermore, given the increasing awareness and concern for the important seismic worldwide risk, new developments have arisen in earthquake engineering. Nonetheless, simplified numerical models are widely used (given their moderate computational cost), and many developments rely mainly on them. The authors have started a long-term research whose final objective is to provide, by using advanced numerical models, solid basis for these developments. Those models are based on continuum mechanics, and consider Plastic Damage Model to simulate concrete behavior. Within this context, this paper presents a new methodology to calculate damage variables evolution; the proposed approach is based in the Lubliner/Lee/Fenves formulation and provides closed-form expressions of the compressive and tensile damage variables in terms of the corresponding strains. This methodology does not require calibration with experimental results and incorporates a strategy to avoid mesh-sensitivity. A particular algorithm, suitable for implementation in Abaqus, is described. Mesh-insensitivity is validated in a simple tension example. Accuracy and reliability are verified by simulating a cyclic experiment on a plain concrete specimen. Two laboratory experiments consisting in pushing until failure two 2-D RC frames are simulated with the proposed approach to investigate its ability to reproduce actual monotonic behavior of RC structures; the obtained results are also compared with the aforementioned simplified models that are commonly employed in earthquake engineering.Postprint (published version