Multichannel operation of an integrated acousto-optic wavelength routing switch for WDM systems

Polarization independent acousto-optic tunable filters (PIAOTF's) can operate as transparent wavelength-selective crossconnects to route signals in wavelength division multiplexed optical networks. In this paper, a new low power PIAOTF is characterized as a switch in multiwavelength operation, using four equally spaced lightwave signals with wavelengths between 1546 nm and 1558 nm. Interchannel interference due to sidelobe excitation is lower than -11 dB for single wavelength switching and is equal to -6 dB in the extreme case of simultaneous switching of all wavelength channels. Sources of interport and interchannel crosstalk for single and multiple wavelength switching are identified

A Simulation Model for Logical and Operative Clash Detection

The introduction of the Building Information Modeling (BIM) approach has facilitated the management process of documents produced by different kinds of professionals involved in the design and/or renovation of a building, through identification and subsequent management of geometrical interferences (Clash Detection). The methodology of this research proposes a tool to support Clash Detection, introducing the logical-operative dimension, that may occur with the presence of a construction site within a hospital structure, through the integration of a BIM model within a Game Engine environment, to preserve the continuity of daily hospital activities and trying to reduce negative impacts, times and costs due to construction activities

CXCL16/CXCR6 axis drives microglia/macrophages phenotype in physiological conditions and plays a crucial role in glioma

Microglia are patrolling cells that sense changes in the brain microenvironment and respond acquiring distinct phenotypes that can be either beneficial or detrimental for brain homeostasis. Anti-inflammatory microglia release soluble factors that might promote brain repair; however, in glioma, anti-inflammatory microglia dampen immune response and promote a brain microenvironment that foster tumor growth and invasion. The chemokine CXCL16 is expressed in the brain, where it is neuroprotective against brain ischemia, and it has been found to be over-expressed in glioblastoma (GBM). Considering that CXCL16 specific receptor CXCR6 is diffusely expressed in the brain including in microglia cells, we wanted to investigate the role of CXCL16 in the modulation of microglia cell activity and phenotype, and in the progression of glioma. Here we report that CXCL16 drives microglia polarization toward an anti-inflammatory phenotype, also restraining microglia polarization toward an inflammatory phenotype upon LPS and IFN? stimulation. In the context of glioma, we demonstrate that CXCL16 released by tumor cells is determinant in promoting glioma associated microglia/macrophages (GAMs) modulation toward an anti-inflammatory/pro-tumor phenotype, and that cxcr6ko mice, orthotopically implanted into the brain with GL261 glioma cells,survive longer compared to wild-type mice. We also describe that CXCL16/CXCR6 signaling acts directly on mouse glioma cells, as well as human primary GBM cells, promoting tumor cell growth, migration and invasion. All together these data suggest that CXCL16 signaling could represent a good target to modulate microglia phenotype in order to restrain inflammation or to limit glioma progression

El concepto de energía en los libros de textos : de las concepciones previas a la propuesta de un nuevo sublenguaje

In this work are studied the already existing interpretations and conceptions on the concept of energy and other allied concepts in Basic Physics textbooks commonly used in the initial courses at university and in courses prior to university level (Basic School) being given in Venezuela. In this study we have used techniques of analysis of content and have made a historic analysis to round up the conclusions of the work. It becomes necessary to build a new language, simple but internally coherent, and within the current scientific paradigms. In this work we start the discussion of this new language within the area of energy and related concepts

GEOMETRIC-PROPERTIES OF THE PRUNING FRONT

Monotonicity of the prunig front is proved for the Lozi map. A general expression for its Hausdorff dimension is also derived which takes into account multifractal fluctuations as wel

Los estilos de prosa y el enfoque ciencia-tecnología-sociedad en textos universitarios de química general

En este trabajo se estudiaron los estilos de prosa científica y el enfoque ciencia-tecnología-sociedad en textos de química de los cursos básicos universitarios en Venezuela, usando técnicas de análisis de contenido. Se encuentra que el estilo de prosa más utilizado es el conocimiento en ciencia y que se da poca importancia al enfoque ciencia-tecnología-sociedad.In this work we studied prose structures and STS interactions in basic chemistry textbooks commonly used in the initial university courses given in Venezuela with techniques of analysis of content. We have found the most used prose structure to be the knowledge of science, showing little interest in STS interactions

La calidad científica del contenido sobre el tema de la estructura de la materia en textos universitarios de química general

En este trabajo se estudian algunos conceptos e ideas científicas sobre el tema de la estructura de la materia en los textos de química más usados en los cursos básicos universitarios en Venezuela, usando técnicas de análisis de contenido. Se encuentra que los textos analizados presentan algunos casos de explicaciones y conceptos con un alto grado de inexactitud e imprecisión y un uso inapropiado de los niveles macroscópico y microscópico, lo que podría generar concepciones erróneas en el estudiante.In this paper we study some concepts and scientific ideas about the structure of matter in General Chemistry textbooks commonly used in Venezuela's initial university courses, using techniques of content analysis. We have found that the analysed textbooks sometimes show explanations and concepts with a high degree of inaccuracy and imprecision and an inappropriate use of the macroscopic and microscopic levels, which could generate wrong conceptions in the student

Thinning affects water-use efficiency of hardwood saplings naturally recruited in a Pinus radiata D. Don plantation.

Plantations for timber production combine the productive to the nursery function for natural regeneration of native species. Thinning plays a crucial role in recruitment and establishment of native species, by modifying the irradiance regime beneath the canopy cover. It also promotes the secondary succession towards a more stable forest, which is a main goal in protected areas. The present study was carried in a timber plantation of Pinus radiata D. Don, located in the National Park of Cilento and Vallo di Diano (Southern Italy). The ecophysiological responses of saplings of two hardwood species, Quercus cerris L. and Fraxinus ornus L., according to two contrasting (low and high) relative irradiance (RI) regimes were analysed. Leaf and tree ring δ13C values were employed as indicators of water use efficiency (WUE) to explore plant responses to light regime. A preliminary methodological comparison between bulk wood and extracted holocellulose showed no significant differences in δ13C between the two materials. Results indicate lower δ13C values, thus suggesting a lower WUE, at higher RI regimes (corresponding to heavy thinning) for both the studied species. Furthermore, Q. cerris δ13C values are lower than those of F. ornus. These results suggest that, under the same light conditions, the mesophile Q. cerris exhibits a weaker stomatal control than the xerophile F. ornus, which keeps higher WUE. In the mesic environment studied, Q. cerris may overcome F. ornus in the long run, owing to a heavy thinning