Modular Planar Antenna at X-band for satellite communications

An antenna which has been conceived as a portable system for satellite communications based on the recommendations ITU-R S.580-6 [1] and ITU-R S.465-5 [2] for small antennas, i.e., with a diameter lower than 50 wavelengths, is introduced. It is a planar and a compact structure with a size of 40×40×2 cm. The antenna is formed by an array of 256 printed elements covering a large bandwidth (14.7%) at X-Band. The specification includes transmission (Tx) and reception (Rx) bands simultaneously. The printed antenna has a radiation pattern with a 3dB beamwidth of 5°, over a 31dBi gain, and a dual and an interchangeable circular polarizatio

Portable low profile antenna at X-band

An antenna which has been conceived as a portable system for satellite communications based on the recommendations ITU-R S.580-6 and ITU-R S.465-5 for small antennas, i.e., with a diameter lower than 50 wavelengths, is introduced. It is a planar and a compact structure with a size of 40×40×2 cm. The antenna is formed by an array of 256 printed elements covering a large bandwidth (14.7%) at X-Band with a VSWR of 1.4:1. The specification includes transmission (Tx) and reception (Rx) bands simultaneously. The printed antenna has a radiation pattern with a 3dB beamwidth of 5°, over a 31dBi gain, and a dual and an interchangeable circular polarization

El pensamiento de los profesores de Educación Física sobre los factores que inciden en el síndrome del burnout

El presente estudio tiene el propósito de indagar acerca de lo que piensan los profesores de educación física de educación primaria y secundaria acerca de los factores que influyen de forma positiva o negativa en el estrés, el malestar docente y/o el síndrome del Burnout. La investigación se sitúa en el marco de las investigaciones cualitativas. La técnica utilizada para recoger información ha sido el Focus Group (grupo de discusión). Según los participantes en el estudio los factores que contribuyen al Burnout son, entre otros el individualismo, las actitudes de queja, defensivas y rígidas, la rutina, los estilos pasivos de afrontamiento de los problemas, mientras que los aspectos que previenen el Burnout son: la cooperación entre los colegas, las actitudes positivas, el compromiso y la vocación.In this article, we provide the results of a study we carried out on the perceptions of public primary and secondary school physical education teachers regarding factors that may promote or inhibit burnout. The data were obtained through a focus group interview. The interview was audiotaped and later transcribed to facilitate data analysis. The analysis was conducted by three co-investigators so as to ensure consistency in the interpretation of the data. According to the participants, the following factors contribute to teacher burnout in physical education: Individualism, a complaining attitude, defensiveness, a lack of commitment, irresponsibility, convenience and routine, a lack of a teaching vocation, and passive coping styles. By contrast, co-operative behavior, open-mindedness and optimism, responsibility and commitment, a teaching vocation, and an internal locus of control are factors that, according to the participants, could help prevent teacher burnout

La incidencia del tributo en la propiedad inmobiliaria

Este trabajo hace un análisis de la repercusión que tienen sobre la propiedad inmobiliaria los impuestos más importantes que se le aplican.Grado en Derech

Physical-chemical changes in karst water: teaching resources

El proceso de karstificación sobre las rocas carbonatadas y sus morfologías resultantes son aspectos que suelen abordarse desde un enfoque generalmente descriptivo. Habitualmente se parte de unos fundamentos elementales del proceso químico, para pasar directamente a la descripción del modelado del paisaje kárstico. En el presente trabajo se proponen diversas actividades cuyo objetivo conjunto es lograr una visión integral y algo más tangible del proceso de karstificación. Con un enfoque transversal con otras disciplinas, como son la química o la biología, se han planteado diferentes actividades de clase, campo y/o laboratorio, basadas en las transformaciones químicas que experimenta el agua al estar en contacto con los materiales karstificables. Las actividades se plantean para que cada docente pueda adaptarlas a su entorno más próximo, de forma que el alumnado entienda que se trata de un proceso activo y cercano.The karstification of carbonates and the resulting geomorphological landscapes are frequently studied from a general descriptive point of view. We tend to use basic chemical concepts and then proceed right away to describing the karstic landscapes. In the present paper, we propose different activities in order to achieve a whole, real vision of the karstification process, based on the geochemical interaction between water and soluble carbonates. The proposed field, lab and class tasks present a transversal approach with other subjects such as chemistry and biology. These activities can be carried out both individually and in groups, and the teacher can adapt them to their immediate environment, so that the students understand that karstification is an active process happening in their vicinity

Low-Profile Dual Circularly Polarized Antenna Array for Satellite Communications in the X Band

A planar antenna is introduced that works as a portable system for X-band satellite communications. This antenna is low-profile and modular with dimensions of 40 × 40 × 2.5 × cm. It is composed of a square array of 144 printed circuit elements that cover a wide bandwidth (14.7%) for transmission and reception along with dual and interchangeable circular polarization. A radiation efficiency above 50% is achieved by a low-loss stripline feeding network. This printed antenna has a 3 dB beamwidth of 5°, a maximum gain of 26 dBi and an axial ratio under 1.9 dB over the entire frequency band. The complete design of the antenna is shown, and the measurements are compared with simulations to reveal very good agreement

The causal effects of product innovation, web technology and vertical integration on firm efficiency in the fashion industry

This paper examines the interaction among product innovation, web technology and vertical integration, and their effects on firm efficiency in the fashion industry. One contribution of this work is that we do not assume the effect of these variables on firm efficiency to be monotonic. Additionally, rather than using standard financial ratios, we use the Data Envelopment Analysis (DEA) methodology to measure efficiency. Our results indicate that product innovation has a monotonic and positive effect on efficiency. On the contrary, web technology, as a process innovation, does not always positively affect firm efficiency: it exerts a negative effect during the first stages of the technology implementation, and then it becomes positive when the implementation is more advanced. On the other hand, web technology moderates positively the effect that vertical integration has on efficiency.Dep. of Business Organizatation and MarketingPostprin

Composición química de la carne de conejo silvestre (Oryctolagus cuniculus) y viabilidad de su predicción mediante espectroscopía de infrarrojo cercano

En algunos países del entorno mediterráneo existe tradición de consumo de carne de conejo silvestre procedente de la caza. Sin embargo, las características de la canal y de la carne de esta especie cinegética han sido escasamente investigadas. Los objetivos de este estudio fueron analizar la composición química de la carne de conejo silvestre (Oryctolagus cuniculus algirus) procedente del sudoeste de la Península Ibérica y estudiar la viabilidad de la puesta a punto de una metodología rápida de análisis para su determinación mediante espectroscopía de infrarrojo cercano (NIRS). La carne de conejo silvestre de la subespecie O. c. algirus contiene un 23,7% de proteína bruta, 0,2% de grasa bruta, 74,9% de humedad y 1,2% de cenizas. Esta composición difiere de la publicada para conejos domésticos y para conejos silvestres de la subespecie O. c. cuniculus, siendo más magra debido a su mayor contenido de proteína y muy inferior valor de grasa. Se obtuvieron modelos basados en la espectroscopía NIR con buena capacidad de predicción para los parámetros proteína y humedad (r2 = 0,70 y ETVC = 0,39%; y r2 = 0,73 y ETVC = 0,38%; respectivamente); mientras que las calibraciones seleccionadas para grasa y cenizas no resultaron ser aceptables.Wild rabbit meat is commonly consumed in many Mediterranean countries. However, the characteristics of the carcass and meat of this game species have been scarcely investigated. This study was aimed at analysing the chemical composition of hunted wild rabbit (Oryctolagus cuniculus algirus) meat from Southern Iberian Peninsula, and studying the viability of a rapid analytical methodology for its determination by near infrared spectroscopy. Meat of the wild rabbit subspecies O. c. algirus has 23.7% of crude protein, 0.2% of crude fat, 74.9% of moisture and 1.2% of ash. This composition differed from the values published for domesticated rabbits and for wild rabbits of the O. c. cuniculus subspecies, it being leaner due to its higher protein content and its very lower fat content. NIR spectroscopy models obtained displayed a good predictive ability for the estimation of crude protein and moisture contents (r2 = 0.70 and SECV = 0.39%, and r2 = 0.73 and SECV = 0.38%, respectively), while the calibrations selected for crude fat and ash contents were not acceptabl