The Readiness of EVN Telescopes for the SKA-VLBI Era

The application of VLBI to scientific problems has undergone a relentless expansion since its conception, yet the potential for further expansion is still large. We are on the cusp of revolutionary progress given the arrival of a host of next-generation instruments. Over the last few years the community has been working hard to ensure the SKA design includes the capability to enable multiple simultaneous tied-array beams, which is a crucial technology to deliver ultra-precise astrometry and improve survey speed capabilities. However, to reach the full potential requires that the network of antennas is upgraded to match the SKA capabilities. We identify multiple-pixel technology, on large telescopes and connected arrays, as a crucial missing component and here will make recommendations for the upgrade path of the partner EVN (and other network) telescopes. Our feasibility studies on SKA-VLBI suggest an order of magnitude improvement in the precision and also in the frequency range at which astrometry can be performed today, if the full network has the required capabilities.Comment: https://pos.sissa.it/428/058/pd

The KaVA and KVN Pulsar Project

We present our work towards using the Korean VLBI (Very Long Baseline Interferometer) Network (KVN) and VLBI Exploration of Radio Astronomy (VERA) arrays combined into the KVN and VERA Array (KaVA) for observations of radio pulsars at high frequencies ($\simeq$22-GHz). Pulsar astronomy is generally focused at frequencies approximately 0.3 to several GHz and pulsars are usually discovered and monitored with large, single-dish, radio telescopes. For most pulsars, reduced radio flux is expected at high frequencies due to their steep spectrum, but there are exceptions where high frequency observations can be useful. Moreover, some pulsars are observable at high frequencies only, such as those close to the Galactic Center. The discoveries of a radio-bright magnetar and a few dozen extended Chandra sources within 15 arc-minute of the Galactic Center provide strong motivations to make use of the KaVA frequency band for searching pulsars in this region. Here, we describe the science targets and report progresses made from the KVN test observations for known pulsars. We then discuss why KaVA pulsar observations are compelling.Comment: To appear in PASJ KaVA Special Issu

Evaluación ambiental de terminales de usuario multiantena en redes LTE-A

Este trabajo tiene como objetivos el análisis medioambiental de los terminales de usuario (UE) en redes LTE-A que incorporen estructuras MIMO y su posible influencia sobre el abonado. Inicialmente se describen los principios de funcionamiento así como las características y ventajas de los sistemas MIMO. A continuación se estudian los escenarios más probables para la explotación comercial de estos equipos, entre las que cabe destacar el control y la gestión de cultivos en invernaderos, y se analizan desde un punto de vista ambiental. Por último, se obtienen conclusiones sobre su posible repercusión en la salud del usuario

Estudio de reflectarray multihaz para aplicaciones de satélite en banda Ka utilizando discriminación en frecuencia

This contribution describes a design concept based on beam squint effect in printed reflectarrays that allows to produce multiple contiguous beams at 19.5 and 20 GHz, by discriminating in frequency. A 1.6-m reflectarray has been proposed to produce 10 beams separated 0.5 degree using five feeds with frequency reuse. The simulated radiation patterns show a peak gain better than 47.6 dBi, with side-lobe levels close to -24 dB. The proposed concept can be suitable for multiple spot beam satellites in Ka-band

Occupational exposure to carbon dioxide, ammonia and hydrogen sulphide on livestock farms in north-west Spain

The influence of the type of farming on harmful gas exposures to carbon dioxide (CO2 ), ammonia (NH3 ) and hydrogen sulfide (H2 S) was assessed from the perspective of animal welfare and occupational hygiene. Summer data of H2 S, NH3 and CO2 concentrations and of environmental parameters were collected from 31 farms. The indices of exposure for longterm exposures to NH3 suggest the lowest acceptability of exposure was observed on poultry farms. CO2 had the highest dependence on production activity. For H2 S, no differences were found based on farming activity. Both the stocking density and volume of air available affected the daily exposure and the index of exposure to CO2 . Significant differences were observed between hourly CO2 concentrations, depending on the level of activity inside the building. A positive correlation was found between gas concentrations and temperature increase. All values of daily and short-term exposures were below exposure limit values, which suggests that exposure conditions were appropriate for workers’ health during the measurement period. Analysis of the working hours and average hourly concentration of gases during the times of day, with presence of workers inside the farm buildings, revealed significant differences for CO2 .This study was supported by the Sociedade Galega de Prevención de Riscos Laborais [2008/CE257]S

Simultaneous VLBI Astrometry of H2O and SiO Masers toward the Semiregular Variable R Crateris

We obtained, for the first time, astrometrically registered maps of the 22.2 GHz H2O and 42.8, 43.1, and 86.2 GHz SiO maser emission toward the semiregular b-type variable (SRb) R Crateris, at three epochs (2015 May 21, and 2016 January 7 and 26) using the Korean Very-long-baseline Interferometry Network. The SiO masers show a ring-like spatial structure, while the H2O maser shows a very asymmetric one-side outflow structure, which is located at the southern part of the ring-like SiO maser feature. We also found that the 86.2 GHz SiO maser spots are distributed in an inner region, compared to those of the 43.1 GHz SiO maser, which is different from all previously known distributions of the 86.2 GHz SiO masers in variable stars. The different distribution of the 86.2 GHz SiO maser seems to be related to the complex dynamics caused by the overtone pulsation mode of the SRb R Crateris. Furthermore, we estimated the position of the central star based on the ring fitting of the SiO masers, which is essential for interpreting the morphology and kinematics of a circumstellar envelope. The estimated stellar coordinate corresponds well to the position measured by Gaia

Study of bifocal dual reflectarray configurations for multi-beam antennas in ka-band

This paper describes the design of multi-beam dual reflectarray antennas for operation in the Ka-band satellite transmission band (around 20 GHz), using the bifocal design concept to improve antenna performance. This technique has been first applied to obtain beam compression with adjacent feeds, resulting in low radiation efficiency. Then it has been used without beam compression to correct beam aberration, showing better results than an equivalent single-focus reference reflector. The simulated radiation patterns in the elevation plane and the amplitude distributions of the incident field on each reflectarray have been calculated for different antenna configurations

ICTs go hand by hand early childhood Education

La revolución tecnológica está provocando que la sociedad actual esté en continuo cambio, que siempre haya algo nuevo y que lo nuevo pase rápidamente a ser viejo y entre en desuso. El alumnado, como nativo digital, forma parte implícita de este proceso, pero requiere de una formación y educación tecnológica y audiovisual que le capacite para desarrollarse de forma reflexiva y crítica para no convertirse en un sujeto pasivo, crédulo y manipulable. Se hace necesaria la readaptación de todo el entorno educativo, incluyendo el espacio de enseñanza, dinamizándolo y equipándolo de los medios necesarios, fomentando la atención y la participación del alumnado, de manera que se facilite el aprendizaje y la educación en valores. En el siguiente artículo se detalla la experiencia llevada a cabo en un centro de Educación Infantil con la puesta en práctica de un taller de medios audiovisuales dirigido al alumnado de 2/3 años basado en el cine como recurso didáctico.The technological revolution is causing the current society to be in constant change, that there is always something new and that the new thing quickly becomes old and goes into disuse. Students, as digital natives, are an implicit part of this process, but they need technological and audiovisual training and education that enables them to develop in a reflexive and critical manner so as not to become a passive, credulous and manipulable subject. “The image is manipulable, people should not be” (Granado, 2003). Due to this, it is necessary to readjust the entire educational environment, including the teaching space, energizing it and equipping it with the necessary means, thus encouraging the attention and participation of the students, in order to facilitate the learning. The following article refers to a written document detailing the experience carried out in an Early Childhood Education Center with the implementation of an audiovisual media workshop aimed at students of two and three years old, based on “The Cinema as a Didactic Resource” and education in values

Cambios electromiográficos en la musculatura de hombro tras una manipulación torácica de alta velocidad y baja amplitud: un estudio piloto

Tesis (Licenciatura en Kinesiología)Este estudió tuvo como objetivo general, evaluar el efecto de la manipulación torácica, sobre la actividad electrofisiológica, de los músculos implicados en el gesto de alcance. Para cumplir este objetivo, se realizó un diseño pre-prueba, post-prueba con grupo control, el cual abarcó una medición de electromiografía en los músculos Trapecio inferior y Deltoides posterior, antes y después de una manipulación vertebral. Las mediciones se realizaron durante la fase de transporte del gesto de alcance, donde se obtuvieron los porcentajes de activación y la amplitud de señal de los músculos mencionados. La población de estudio corresponde a hombres entre 19 y 25 años, estudiantes universitarios de la carrera de Kinesiología de la Universidad Nacional Andrés Bello, que estaban cursando entre 1er y 5to año de la carrera, durante los años 2014-2015. A todos los sujetos se les midió la altura desde el suelo al hombro en sedente y la distancia del alcance funcional para preparar las alturas de la silla y la mesa. Posteriormente, se identificó el brazo dominante y se procedió a realizar las pruebas de CVM para ambos músculos. Una vez determinada la CVM para ambos músculos, se procedió a evaluar el gesto de alcance, para lo cual el usuario debió sentarse en la silla frente a la mesa con el vaso de agua (previamente regulados). En cuanto a los datos obtenidos, cabe destacar que se presentaron cambios significativos tanto en los porcentajes de activación como en la amplitud de la señal de los músculos implicados en la estabilización de hombro durante un gesto de alcance, luego de una intervención TMO en comparación a una terapia placebo. Este estudio puede contribuir a abrir nuevos caminos a profesionales de la salud para seguir estudiando y evidenciando los efectos e implicancias clínicas que trae la intervención TMO, y así buscar nuevos enfoques terapéuticos, y en el mejor de los casos, mejores resultados de tratamiento