Blogs as virtual environments for teaching and learning in Higher Education

The transformation of the Information and Communication Technologies (ICT) into knowledge and learning technologies is increasingly becoming a matter of concern. Teaching settings associated with the use of blogs in Higher Education are presented in this paper, proceeding from an innovative learning experience of projects carried out by a group of professors between 2009 and 2013. Both, teachers and students who took part in the subjects that implemented the blog, considered it as helpful resource to create a virtual and learning-teaching environment due to the multiple potentialities it offers. Among some of these potentialities, some stand out: it makes easier the access to knowledge, promotes a more active and reflective learning, expands the social experience of learning, provides evidence about the students’ progress which helps to reorient the teaching-learning process, and encourages the critical judgment. Nevertheless, several problems related with the students’ participation and the teacher’s blog management have been identified.

Las Comisiones del Mapa de España en la década de 1850

La necesidad de contar con un mapa de base científica que cubriera todo el territorio español llevó al Estado a crear en paralelo varias Comisiones con cometidos geodésicos, topográficos y cartográficos durante la década de 1850. La labor simultánea de estas Comisiones se prolongó hasta 1859, cuando se aprobó la Ley de Medición del Territorio, que las fusionó en un único organismo. Este artículo analiza aspectos técnicos de los trabajos que realizaron estas Comisiones a partir de la información contenida en algunos documentos que custodia el Archivo Topográfico del IGN. Las conclusiones que se extraen son que estas Comisiones acometieron operaciones geodésicas que resultaron cruciales en el establecimiento ulterior de la red de triangulación peninsular, realizaron mediciones topográficas que fueron reutilizadas veinte años después en el levantamiento del Mapa Topográfico Nacional, e idearon las características catastrales que fueron adoptadas durante todo el siglo posterior para el Catastro de España.

Los grandes sistemas de abastecimiento de agua en el litoral de Alicante

El litoral de Alicante ha sufrido grandes transformaciones territoriales desde las décadas de 1960 y 1970 a raíz de la actividad turística. Uno de los servicios que necesita esta actividad, entre otros, es el abastecimiento de agua potable. En este sentido, por su papel estratégico, el suministro de agua en alta es decisivo para abastecer a los municipios turístico-residenciales. El objetivo de este estudio es conocer y analizar los diferentes sistemas de abastecimiento de agua en alta en la costa de Alicante, sus características, infraestructuras, recursos hídricos disponibles y medidas de gestión llevados a cabo. Algunas de las conclusiones extraídas son el papel estratégico que ejercen en el territorio, especialmente con el agua, un recurso escaso y de vital importancia para la orla costera alicantina, sobre todo en los meses estivales.

Rubén Darío's new unpublished and unknown documents: on La "Isla de Oro", the "Poema del Otoño" and the years of "Mundial"

This article studies and reproduces a group of documents that includes some hand-written and typed texts most likely authored by Rubén Darío, along with others where Darío’s authorship can be easily contested. These documents seem to have originated during the years of Mundial Magazine (1912-1914), and besides the interest for their probably unpublished nature, they also show the cooperation between Darío and his collaborators in the preparation of his original manuscripts right before being sent to the publishers.

Subwavelength resolution for horizontal and vertical polarization by coupled arrays of oblate nanoellipsoids

A structure comprising a coupled pair of two-dimensional arrays of oblate plasmonic nanoellipsoids in a dielectric host medium is proposed as a superlens in the optical domain for both horizontal and vertical polarizations. By means of simulations it is demonstrated that a structure formed by silver nanoellipsoids is capable of restoring subwavelength features of the object for both polarizations at distances larger than half wavelength. The bandwidth of subwavelength resolution is in all cases very large (above 13%). (C) 2009 Optical Society of America

Sub-Wavelength Profile 2-D Leaky-Wave Antennas With Two Periodic Layers

A fast and accurate analysis and synthesis technique for high-gain sub-wavelength 2-D Fabry-Perot leaky-wave antennas (LWA) consisting of two periodic metallodielectric arrays over a ground plane is presented. Full-wave method of moments (MoM) together with reciprocity is employed for the estimation of the near fields upon plane wave illumination and the extraction of the radiation patterns of the LWA. This yields a fast and rigorous tool for the characterisation of this type of antennas. A thorough convergence study for different antenna designs is presented and the operation principles of these antennas as well as the radiation characteristics are discussed. Moreover, design guidelines to tailor the antenna profile, the dimensions of the arrays as well as the antenna directivity and bandwidth are provided. A study on the radiation efficiency for antennas with different profiles is also presented and the trade off between directivity and radiation bandwidth is discussed. Numerical examples are given throughout to demonstrate the technique. A finite size antenna model is simulated using commercial software (CST Microstripes 2009) which validates the technique.

Power Stored and Quality Factors in Frequency Selective Surfaces at THz Frequencies

A study of the external, loaded and unloaded quality factors for frequency selective surfaces (FSSs) is presented. The study is focused on THz frequencies between 5 and 30 THz, where ohmic losses arising from the conductors become important. The influence of material properties, such as metal thickness, conductivity dispersion and surface roughness, is investigated. An equivalent circuit that models the FSS in the presence of ohmic losses is introduced and validated by means of full-wave results. Using both full-wave methods as well as a circuit model, the reactive energy stored in the vicinity of the FSS at resonance upon plane-wave incidence is presented. By studying a doubly periodic array of aluminium strips, it is revealed that the reactive power stored at resonance increases rapidly with increasing periodicity. Moreover, it is demonstrated that arrays with larger periodicity-and therefore less metallisation per unit area-exhibit stronger thermal absorption. Despite this absorption, arrays with higher periodicities produce higher unloaded quality factors. Finally, experimental results of a fabricated prototype operating at 14 THz are presented.

Near-field enhancement for infrared sensor applications

A detailed investigation on planar two dimensional metallodielectric dipole arrays with enhanced near-fields for sensing applications was carried out. Two approaches for enhancing the near-fields and increasing the quality factor were studied. The reactive power stored in the vicinity of the array at resonance increases rapidly with increasing periodicity. Higher quality factors are produced as a result. The excitation of the odd mode in the presence of a perturbation gives rise to a sharp resonance with near-field enhanced by at least an order of magnitude compared to unperturbed arrays. The trade-off between near-field enhancement and thermal losses was also studied, and the effect of supporting dielectric layers on thermal losses and quality factors were examined. Secondary transmissions due to the dielectric alone were found to enhance and reduce cyclically the quality factor as a function of the thickness of the dielectric material. The performance of a perturbed frequency selective surface in sensing nearby materials was investigated. Finally, unperturbed and perturbed arrays working at infrared frequencies were demonstrated experimentally. (C) 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.3604785]