Seguimiento de la evolución de los niveles de salinidad y nitratos en el acuífero superficial de Zafarraya y en fincas de hortícolas al aire libre

La horticultura al aire libre del Llano de Zafarraya es el motor económico de la comarca. El riego de este sector se sustenta en el sistema acuífero del Polje de Zafarraya y Sierra Gorda. En estos acuíferos, como consecuencia de la explotación agrícola de la zona, se viene produciendo desde hace décadas sobreexplotación del recurso, con la consiguiente salinización y nitrificación. Los objetivos de este trabajo han sido estudiar los niveles de salinidad y nitratos de las aguas del acuífero de Zafarraya y hacer un seguimiento de la solución del suelo en explotaciones hortícolas de la zona, para poder realizar recomendaciones que permitan mejorar la gestión de la fertilización y evitar el aumento de la contaminación por nitratos. Los niveles de salinidad obtenidos a lo largo del periodo de estudio han sido estables y no representan problemas para los principales cultivos hortícolas de la zona. En lo que respecta a la concentración de nitratos, los resultados muestran niveles excesivos por encima de 300 mg L-1. Estos resultados son consecuencia de la práctica habitual de aplicaciones excesivas de fertilizantes nitrogenados. La recomendación inicial sería mantener una concentración de nitratos estable a lo largo del ciclo de cultivo para evitar acumulaciones en el suelo sobre todo al final del mismo

Influencia que sobre las propiedades físico-mecánicas de los morteros de cemento Portland tiene la adición de colofonia y tanino

The colophony has been used as an admixture in the Portland cement mortar with the intention to observe its influence on the air content, water absorption, adhesive capacity and mechanical properties. The results obtained have shown that, the colophony acts as air entrainment, reduces the permeability and improves the adhesion between the past and aggregates. Likewise, the addition of tannin and montan wax to the colophony has the efect of reducing the formation of foam and improves the impermeability of the mortar.Se ha empleado la colofonia como aditivo en el mortero de cemento portland con el fin de observar su influencia sobre el contenido de aire, absorción de agua, capacidad adhesiva y propiedades mecánicas. Los resultados obtenidos han puesto de manifiesto que la colofonia actúa como aireante, aumenta la impermeabilidad y mejora la adherencia de la pasta al árido. Asimismo, la adición de tanino y cera montana a la colofonia tiene el efecto de reducir la formación de espuma y mejorar también la impermeabilidad del mortero

Comparación de las medidas de humedad en suelo enarenado con diferentes sensores

Poster[ES] Una opción ambiciosa para gestionar el riego es emplear sensores como activadores del riego. El éxito de la automatización del riego empleando sensores de humedad de suelo depende, entre otros factores, de la adaptación del sensor a las características del suelo. El objetivo de este trabajo es evaluar el comportamiento de tres equipos de medida de humedad en un suelo enarenado característico de los cultivos hortícolas bajo abrigo desarrollados en el Sureste de España.El trabajo ha sido cofinanciado por Fondos Europeos (FSE y FEDER) y la Consejería de Agricultura y Pesca (IFAPA Junta de Andalucía) mediante el Proyecto Transforma Conecta SAR (PP.TRA.TRA201300.10).Baeza Cano, R.; Contreras París, J.; Alonso López, F.; Cánovas Fernández, G.; López Segura, J. (2014). Comparación de las medidas de humedad en suelo enarenado con diferentes sensores. En CONFERENCIA INTERNACIONAL INFOACES. UN SISTEMA DE INFORMACIÓN PARA LAS UNIVERSIDADES LATINOAMERICANAS. LIBRO DE ACTAS. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/94683OC

Night Myopia Studied with an Adaptive Optics Visual Analyzer

PURPOSE: Eyes with distant objects in focus in daylight are thought to become myopic in dim light. This phenomenon, often called "night myopia" has been studied extensively for several decades. However, despite its general acceptance, its magnitude and causes are still controversial. A series of experiments were performed to understand night myopia in greater detail. METHODS: We used an adaptive optics instrument operating in invisible infrared light to elucidate the actual magnitude of night myopia and its main causes. The experimental setup allowed the manipulation of the eye's aberrations (and particularly spherical aberration) as well as the use of monochromatic and polychromatic stimuli. Eight subjects with normal vision monocularly determined their best focus position subjectively for a Maltese cross stimulus at different levels of luminance, from the baseline condition of 20 cd/m(2) to the lowest luminance of 22 × 10(-6) cd/m(2). While subjects performed the focusing tasks, their eye's defocus and aberrations were continuously measured with the 1050-nm Hartmann-Shack sensor incorporated in the adaptive optics instrument. The experiment was repeated for a variety of controlled conditions incorporating specific aberrations of the eye and chromatic content of the stimuli. RESULTS: We found large inter-subject variability and an average of -0.8 D myopic shift for low light conditions. The main cause responsible for night myopia was the accommodation shift occurring at low light levels. Other factors, traditionally suggested to explain night myopia, such as chromatic and spherical aberrations, have a much smaller effect in this mechanism. CONCLUSIONS: An adaptive optics visual analyzer was applied to study the phenomenon of night myopia. We found that the defocus shift occurring in dim light is mainly due to accommodation errors

Recent progress with hot carrier solar cells

Hot carrier solar cells offer one of the most promising options for high performance “third generation” photovoltaic devices. For successful operation, these need to be thin, strongly absorbing, radioactively efficient devices in a simple 2-terminal configuration. Nonetheless, they offer potential performance close to the maximum possible for solar conversion, equivalent to a multi-cell stack of six or more tandem cells possibly without some of the limitations, such as spectral sensitivity. However, hot carrier cells offer some quite fundamental challenges in implementation that our team is addressing in an internationally collaborative effort

EuroPineDB: a high-coverage web database for maritime pine transcriptome

Pinus pinaster is an economically and ecologically important species that is becoming a woody gymnosperm model. Its enormous genome size makes whole-genome sequencing approaches are hard to apply. Therefore, the expressed portion of the genome has to be characterised and the results and annotations have to be stored in dedicated databases

Gaia Data Release 3: Exploring and mapping the diffuse interstellar band at 862 nm

Context. Diffuse interstellar bands (DIBs) are common interstellar absorption features in spectroscopic observations but their origins remain unclear. DIBs play an important role in the life cycle of the interstellar medium (ISM) and can also be used to trace Galactic structure. Aims. Here, we demonstrate the capacity of the Gaia-Radial Velocity Spectrometer (RVS) in Gaia DR3 to reveal the spatial distribution of the unknown molecular species responsible for the most prominent DIB at 862 nm in the RVS passband, exploring the Galactic ISM within a few kiloparsecs from the Sun. Methods. The DIBs are measured within the GSP-Spec module using a Gaussian profile fit for cool stars and a Gaussian process for hot stars. In addition to the equivalent widths and their uncertainties, Gaia DR3 provides their characteristic central wavelength, width, and quality flags. Results. We present an extensive sample of 476 117 individual DIB measurements obtained in a homogeneous way covering the entire sky. We compare spatial distributions of the DIB carrier with interstellar reddening and find evidence that DIB carriers are present in a local bubble around the Sun which contains nearly no dust. We characterised the DIB equivalent width with a local density of 0.19 ± 0.04 kpc1 and a scale height of 98.60 8.46+11.10 pc. The latter is smaller than the dust scale height, indicating that DIBs are more concentrated towards the Galactic plane. We determine the rest-frame wavelength with unprecedented precision (?0 = 8620.86 ± 0.019 in air) and reveal a remarkable correspondence between the DIB velocities and the CO gas velocities, suggesting that the 862 nm DIB carrier is related to macro-molecules. Conclusions. We demonstrate the unique capacity of Gaia to trace the spatial structure of the Galactic ISM using the 862 nm DIB

Gaia Early Data Release 3: The celestial reference frame (Gaia-CRF3)

CONTEXT: Gaia-CRF3 is the celestial reference frame for positions and proper motions in the third release of data from the Gaia mission, Gaia DR3 (and for the early third release, Gaia EDR3, which contains identical astrometric results). The reference frame is defined by the positions and proper motions at epoch 2016.0 for a specific set of extragalactic sources in the (E)DR3 catalogue. AIMS: We describe the construction of Gaia-CRF3 and its properties in terms of the distributions in magnitude, colour, and astrometric quality. METHODS: Compact extragalactic sources in Gaia DR3 were identified by positional cross-matching with 17 external catalogues of quasi-stellar objects (QSO) and active galactic nuclei (AGN), followed by astrometric filtering designed to remove stellar contaminants. Selecting a clean sample was favoured over including a higher number of extragalactic sources. For the final sample, the random and systematic errors in the proper motions are analysed, as well as the radio-optical offsets in position for sources in the third realisation of the International Celestial Reference Frame (ICRF3). RESULTS: Gaia-CRF3 comprises about 1.6 million QSO-like sources, of which 1.2 million have five-parameter astrometric solutions in Gaia DR3 and 0.4 million have six-parameter solutions. The sources span the magnitude range G = 13–21 with a peak density at 20.6 mag, at which the typical positional uncertainty is about 1 mas. The proper motions show systematic errors on the level of 12 µas yr–1 on angular scales greater than 15 deg. For the 3142 optical counterparts of ICRF3 sources in the S/X frequency bands, the median offset from the radio positions is about 0.5 mas, but it exceeds 4 mas in either coordinate for 127 sources. We outline the future of Gaia-CRF in the next Gaia data releases. Appendices give further details on the external catalogues used, how to extract information about the Gaia-CRF3 sources, potential (Galactic) confusion sources, and the estimation of the spin and orientation of an astrometric solution

Gaia Data Release 3: The Galaxy in your preferred colours: Synthetic photometry from Gaia low-resolution spectra

Gaia Data Release 3 provides novel flux-calibrated low-resolution spectrophotometry for '220 million sources in the wavelength range 330 nm ≤ λ ≤ 1050 nm (XP spectra). Synthetic photometry directly tied to a flux in physical units can be obtained from these spectra for any passband fully enclosed in this wavelength range. We describe how synthetic photometry can be obtained from XP spectra, illustrating the performance that can be achieved under a range of different conditions - for example passband width and wavelength range - as well as the limits and the problems affecting it. Existing top-quality photometry can be reproduced within a few per cent over a wide range of magnitudes and colour, for wide and medium bands, and with up to millimag accuracy when synthetic photometry is standardised with respect to these external sources. Some examples of potential scientific application are presented, including the detection of multiple populations in globular clusters, the estimation of metallicity extended to the very metal-poor regime, and the classification of white dwarfs. A catalogue providing standardised photometry for 2.2×108sources in several wide bands of widely used photometric systems is provided (Gaia Synthetic Photometry Catalogue; GSPC) as well as a catalogue of '105 white dwarfs with DA/non-DA classification obtained with a Random Forest algorithm (Gaia Synthetic Photometry Catalogue for White Dwarfs; GSPC-WD)