5,220 research outputs found
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
Using AOP to Automatically Provide Distribution, Fault Tolerance, and Load Balancing to the CORBA-LC Component Model
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
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