Enhancement of the nonlinear optical absorption of the E7 liquid crystal at the nematic-isotropic transition

We present an experimental study of the nonlinear optical absorption of the eutectic mixture E7 at the nematic-isotropic phase transition by the Z-scan technique, under a continuos wave excitation at 532 nm. In the nematic region, the effective nonlinear optical coefficient \beta for an extraordinary beam is negative and for an ordinary beam is positive, being null in the isotropic phase. The parameter S_{NL} defined in terms of the nonlinear absorption coefficients in a similar way than the optical order parameter from the linear dichoic ratio behavies like an order parameter with a critical exponent 0.22+-0.05, in good agreement with the tri-critical hipothesis of the N-I transition.Comment: 11 pages, 6 figures, to be published in the vol 42 of the Brazilian Jurnal of physic

Reduced kinetic mechanisms for modelling LPP combustión in gas turbines

Reduced kinetic mechanisms for modelling LPP combustión in gas turbine

Sonochemical synthesis and stabilization of concentrated antimicrobial silver-chitosan nanoparticle dispersions

This work reports on a green synthetic route to produce concentrated aqueous dispersions of silver nanoparticles (AgNP) employing high-intensity ultrasound (US) and chitosan (CS) as a non-toxic reducing agent for Ag1 salts and AgNP stabilizer. The sonication simultaneously boosted the synthesis and improved the stability of the AgNP, capping them with CS. Hybrid AgNP-CS antimicrobial dispersions, stable for at least 6 months, were synthesized in a simple single step process. The use of US allowed for applying relatively mild processing temperatures (608C) and reaction time between 30 min and 3 h to obtain concentrated disper- sions of AgNP that otherwise could not be obtained even after 72 h under mechanical stirring at the same reaction conditions. Upon sonication spherical AgNP-CS with a size between 60 and 100 nm were generated, in contrast to the average diameter of 200 nm of the particles obtained by stirring. The antibacterial efficiency of the AgNP-CS hybrids was evaluated against the medically relevant pathogens Staphylococcus aureus and Escherichia coli. The US-synthesized AgNP-CS showed more than 3-fold higher antibacterial activity compared to the particles obtained under stirring, due to their higher concentration and smaller size.Postprint (author's final draft

Desafíos del servicio social en el marco de las nuevas políticas sociales

Tras presentar y analizar las transformaciones más recientes del Estado de bienestar, en este artículo se aborda el sentido de la inclusión social, que puede ser interpretada de diversa forma (según diferentes códigos simbólicos). Posteriormente, se observa que el servicio social debe tener presente el actor de la política social, sus lógicas y las diferentes configuraciones de intervención posibles para realizar su actividad. Y, por último, se diseñan las que podrían considerarse líneas guía y palabras clave de las nuevas políticas sociales.After presenting and analyzing the most recent transformations in the Welfare State, this article discusses the sense of social inclusion, which can be interpreted in different ways (according to different symbolic codes). Secondly, it is observed that the social service needs to bear in mind the actor of social politics, its logics and the different possible intervention configurations in order to perform its activity. Lastly, the article designs what could be considered as the guidelines and keywords of new social politics

Estudio de procesos hidrológicos a diferentes escalas (marco teórico y propuesta metodológica)

La comprensión de los procesos hidrológicos requiere el estudio de los mismos en un rango de escalas espacio-temporales lo suficientemente amplio como para poder caracterizarlos correctamente. En el presente trabajo se describe la situación actual del estudio de los procesos hidrológicos a diferentes escalas y se propone un método para la determinación de las escalas de trabajo, el establecimiento de los dominios de escala y el traspaso de información de unas escalas a otras.In order to understand well hydrological processes it is necessary to study them across a wide range of spatial and temporal scales in order to characterize these processes properly. In this paper the state of the art of scale issues is described and a methodology to determine working scales, scale domains and change of information across scales is proposed

La Mentoría como elemento de mejora en el proceso de enseñanza - aprendizaje

Este artículo describe una experiencia de mentoría llevada a cabo dentro de la Universidad de Granada con el objetivo de mejorar la calidad de la enseñanza que en ella se ofrece. Se han realizado diferentes actividades (grabaciones en vídeo y seminarios de formación) que han dado lugar a acciones de mejora concretas de la docencia, la tutoría y la evaluación de los alumnos. A tenor de los resultados de diferentes encuestas, la experiencia ha sido muy positiva no sólo para el profesor mentor y el profesor novel, sino también para sus alumnos.SUMMARY: This paper describes a mentoring experience carried out in the University of Granada with the aim of improving the quality of the education that this offers. Different activities have been performed (video recording and training seminars) which have given rise to concrete measures for the improvement of the teaching, the tutoring, and the evaluation of the students. According to the results of different surveys, the experience has been very positive not only for the mentor and the beginning teacher, but also for their students.Peer Reviewe

Combining Web 2.0 and Web Services in Collaborative Working Environments

Collaborative applications offer significant benefits in business sector. Usually, team members need to use several systems to carry out their tasks. What these users need is an environment which permits them to carry out these tasks automatically, considering the flow of information between the different systems and offering interoperability and composition features. Nowadays, Web Services have gained their prominence in providing these both features. On the other hand, the use of Web 2.0 allows to create web applications in which the user constitutes a key element. What we propose in this paper is the combination of both approaches for creating a Collaborative Working Environment (CWE)

Co-Training for Unsupervised Domain Adaptation of Semantic Segmentation Models

Semantic image segmentation is a central and challenging task in autonomous driving, addressed by training deep models. Since this training draws to a curse of human-based image labeling, using synthetic images with automatically generated labels together with unlabeled real-world images is a promising alternative. This implies to address an unsupervised domain adaptation (UDA) problem. In this paper, we propose a new co-training procedure for synth-to-real UDA of semantic segmentation models. It consists of a self-training stage, which provides two domain-adapted models, and a model collaboration loop for the mutual improvement of these two models. These models are then used to provide the final semantic segmentation labels (pseudo-labels) for the real-world images. The overall procedure treats the deep models as black boxes and drives their collaboration at the level of pseudo-labeled target images, i.e., neither modifying loss functions is required, nor explicit feature alignment. We test our proposal on standard synthetic and real-world datasets for on-board semantic segmentation. Our procedure shows improvements ranging from ~13 to ~26 mIoU points over baselines, so establishing new state-of-the-art results