59 research outputs found

    Distribución y solapamiento espacial de las aves acuáticas y ribereñas en un humedal

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    Spatial distribution of bird community and their niche overlap on Media Luna wetland was the main objective of this work. A wide and heterogeneous use of the system resources were detected, mainlyrelated to feeding and resting activities. By resting activity, most of the species were gregarious, sharing branches and riparian grassland, showing overlap among them. Whereas in feeding activity there was less evident overlap. Piscivorous egrets and herons (Ardeidae) showed high overlap among them, but temporal resources partitioning of nocturnal species such as Nycticorax nycticorax L, or different diet of Bubulcus ibis L, reduce the competence. Some species such as Jacana spinosa L realised all itsactivities in an only type of habitat with the lowest overlap with another species. Low interespecific aggressiveness was observed. Anthropic disturbances may favoured some species abundance and possible decrease of another species. Bad management actions had high consequences in the study area. So, future management actions must consider information of use and resource partitioning of bird group.La distribución espacial de una comunidad de aves y sus niveles de solapamiento dentro del humedal de la Media Luna fue el principal objetivo de este trabajo. Se detectó un uso amplio y heterogéneo del sistema y sus recursos, principalmente en relación a dos actividades: alimentación y descanso. Para descanso, la mayoría de las especies se mostraron gregarias y compartieron ramas deárboles o vegetación ribereña, mostrando solapamiento entre ellas; mientras que en actividad de alimentación hubo un solapamiento de nicho menos evidente. La competencia trófica fue evidente entremiembros de un mismo gremio, como algunas garzas (Ardeidae) piscívoras que mostraron solapamientos mayores al 75% entre sí, pero la repartición temporal de recursos de las especies nocturnas como Nycticorax nycticorax L, o la diferente dieta de Bubulcus ibis L redujeron la competencia. Algunas especies como Jacana spinosa L realizaron todas sus actividades en un sólo tipo de hábitat, con solapamiento menor al 10% con las demás especies. En general se observó poca agresividad interespecífica. Alteraciones antrópicas en el medio pueden favorecer la abundancia de algunas especies en posible decremento de otras. Los resultados mostraron que la repartición en el uso del hábitat es importante para actividades como descanso, además de la alimentación. Acciones de gestión mal llevadas a cabo tuvieron gran repercusión en el área de estudio, por lo que futuras acciones deben considerar información sobre el uso y la repartición de recursos por parte del grupo de las aves, para diferentes actividades

    Effect of Grazing Management on Herbage Accumulation of Lucerne-Orchard Grass Sward

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    Throughout most of México, lucerne (Medicago sativa) is the primary forage legume used in the dairy industry. Unfortunately, lucerne does not grow in late autumn and winter due to adverse weather. Recent studies with lucerne have suggested that the inclusion of a companion grass will invariably increase the seasonal distribution and total annual yield of swards (Laidlaw & Teuber, 2001). However the management of mixed swards containing lucerne is difficult as a grazing frequency or intensity which suits one species may be detrimental to the other. Changes in balance between grass and legume, especially in grazed swards, have been observed. In México mixtures of lucerne-orchard grass have a good persistence and productivity. However the explanation for this is unclear. This study examined the effects of different grazing management practices on lucerne-orchard grass production and seasonal distribution

    COMPARATIVA KINECT VS MYO APLICANDO LA PRUEBA NASA-TLX EN UN ENTORNO DE RVI PARA INSPECCIÓN EN AEROGENERADORES

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    ResumenEste artículo presenta un estudio comparativo entre dos dispositivos de interacción natural de usuario que son frecuentemente utilizados en sistemas de realidad virtual inmersiva: Kinect y Myo. Cada uno de estos dispositivos es usado en un sistema de realidad virtual inmersivo enfocado a la inspección de aerogeneradores. Se realiza una evaluación de ambos empleando como principal instrumento la prueba NASA-TLX, también llamado índice de carga mental. Los resultados permiten corroborar la potencial aplicación de cualquiera de los dos dispositivos. No obstante, el dispositivo Myo aventaja ligeramente al dispositivo Kinect como el más idóneo.Palabras Claves: Energía eólica, interacción natural de usuario, NASA-TLX, realidad virtual inmersiva.COMPARISON KINECT VS MYO APPLYING THE NASA-TLX TEST IN A RVI ENVIRONMENT FOR INSPECTION IN WIND TURBINESAbstractThis paper presents a comparative study between two natural user interaction devices that are frequently used in immersive virtual reality systems: Kinect and Myo. Each of these devices is used in an immersive virtual reality system focused on the inspection of wind turbines. An evaluation of both using the NASA-TLX test, also called mental load index, is the main instrument. The results allow to corroborate the potential application of either device. However, the Myo device slightly outstrips the Kinect device as the most suitable. Keywords: Immersive virtual reality, NASA-TLX, natural user interaction, wind energy

    Polarization Properties of the Solitons Generated in the Process of Pulse Breakup in Twisted Fiber Pumped by ns Pulses

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    Common optical fibers are randomly birefringent, and solitons formatting and traveling in them are randomly polarized. However, it is desirable to have solitons with a well-defined polarization. With pump relatively long pulses, the nonlinear effects of modulation instability (MI) and stimulated Raman scattering (SRS) are dominant at the initial stage of the process of supercontinuum (SC) generation; modulation instability results in pulse breakup and formation of short pulses that evolve finally to a bunch of solitons and dispersive waves. We do the research of the polarization of solitons formed by the pulse breakup process by the effect of modulation instability with pump pulses of nanoseconds in standard fiber (SMF-28) with circular birefringence introduced by fiber twist, and the twisted fiber mitigates the random linear birefringence. In this work, we found that polarization ellipticity of solitons is distributed randomly; nevertheless, the average polarization ellipticity is closer to the circular than the polarization ellipticity of the input pulse. In the experimental setup. 200 m of SMF-28 fiber twisted by 6 turns/m was used. We used 1 ns pulse to pump the fiber. The results showed that at circular polarization of the input pulse solitons at the fiber output have polarizations close to the circular, while in the fiber without twist, the soliton polarization was random

    Modeling the series of (n x 2) Si-rich reconstructions of beta-SiC(001): a prospective atomic wire?

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    We perform ab initio plane wave supercell density functional calculations on three candidate models of the (3 x 2) reconstruction of the beta-SiC(001) surface. We find that the two-adlayer asymmetric-dimer model (TAADM) is unambiguously favored for all reasonable values of Si chemical potential. We then use structures derived from the TAADM parent to model the silicon lines that are observed when the (3 x 2) reconstruction is annealed (the (n x 2) series of reconstructions), using a tight-binding method. We find that as we increase n, and so separate the lines, a structural transition occurs in which the top addimer of the line flattens. We also find that associated with the separation of the lines is a large decrease in the HOMO-LUMO gap, and that the HOMO state becomes quasi-one-dimensional. These properties are qualititatively and quantitatively different from the electronic properties of the original (3 x 2) reconstruction.Comment: 22 pages, including 6 EPS figure

    The CARMENES search for exoplanets around M dwarfs. Stellar atmospheric parameters of target stars with STEPARSYN

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    We determined effective temperatures, surface gravities, and metallicities for a sample of 343 M dwarfs observed with CARMENES, the double-channel, high-resolution spectrograph installed at the 3.5 m telescope at Calar Alto Observatory. We employed STEPARSYN, a Bayesian spectral synthesis implementation particularly designed to infer the stellar atmospheric parameters of late-type stars following a Markov chain Monte Carlo approach. We made use of the BT-Settl model atmospheres and the radiative transfer code turbospectrum to compute a grid of synthetic spectra around 75 magnetically insensitive Fe I and Ti I lines plus the TiO γ and ∈ bands. To avoid any potential degeneracy in the parameter space, we imposed Bayesian priors on Teff and logg based on the comprehensive, multi-band photometric data available for the sample. We find that this methodology is suitable down to M7.0 V, where refractory metals such as Ti are expected to condense in the stellar photospheres. The derived Teff, logg, and [Fe/H] range from 3000 to 4200 K, 4.5 to 5.3 dex, and -0.7 to 0.2 dex, respectively. Although our Teff scale is in good agreement with the literature, we report large discrepancies in the [Fe/H] scales, which might arise from the different methodologies and sets of lines considered. However, our [Fe/H] is in agreement with the metallicity distribution of FGK-type stars in the solar neighbourhood and correlates well with the kinematic membership of the targets in the Galactic populations. Lastly, excellent agreement in Teff is found for M dwarfs with interferometric angular diameter measurements, as well as in the [Fe/H] between the components in the wide physical FGK+M and M+M systems included in our sample. © 2021 ESO.CARMENES is an instrument for the Centro Astronomico Hispano en Andalucia at Calar Alto (CAHA). CARMENES is funded by the German Max-Plank Gesellschaft (MPG), the Spanish Consejo Superior de Investigaciones Cientificas (CSIC), the European Union through FEDER/ERF FICTS-2011-02 funds, and the members of the CARMENES Consortium (Max-Plank-Institut fur Astronomie, Instituto de Astrofisica de Andalucia, Landessternwarte Konigstuhl, Institut de Ciences de l'Espai, Institut fur Astrophysik Gottingen, Universidad Complutense de Madrid, Thuringer Landessternwarte Tautenberg, Instituto de Astrofisica de Canarias, Hamburger Sternwarte, Centro de Astrobiologia and Centro Astronomico Hispano-Andaluz), with additional contributions by the Spanish Ministry of Economy, the German Science Foundation through the Major Research Instrumentation Programme and DFG Research Unit FOR2544 "Blue Planets around Red Stars", the Klaus Tschira Stiftung, the states of BadenWurttemberg and Niedersachsen, and by the Junta de Andalucia. The authors acknowledge financial support from the Fundação para a Ciência e a Tecnologia (FCT) through the research grants UID/FIS/04434/2019, UIDB/04434/2020 and UIDP/04434/2020, national funds PTDC/FIS-AST/28953/2017, by FEDER (Fundo Europeu de Desenvolvimento Regional) through COMPETE2020 Programa Operacional Competitividade e Internacionalizacao (POCI-01-0145FEDER-028953), and the Spanish Ministerio de Ciencia, Innovacion y Universidades, Ministerio de Economia y Competitividad, the Universidad Complutense de Madrid, and the Fondo Europeo de Desarrollo Regional (FEDER/ERF) through fellowship FPU15/01476, and projects AYA2016-79425-C3-1/2/3-P, PID2019-109522GB-C5[1:4]/AEI/10.13039/501100011033, AYA2014-56359-P, BES-2017-080769, and RYC-2013-14875. The authors also acknowledge financial support from the Centre of Excellence "Severo Ochoa" and "Maria de Maeztu" awards to the Instituto de Astrofisica de Canarias (SEV-2015-0548), Instituto de Astrofisica de Andalucia (SEV-2017-0709), and Centro de Astrobiologia (MDM-2017-0737), and the Generalitat de Catalunya/CERCA programme. This work has made use of the VALD database, operated at Uppsala University, the Institute of Astronomy RAS in Moscow, and the University of Vienna, and of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium).Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. V.M.P. acknowledges financial support from NASA through grant NNX17AG24G. S.V.J. acknowledges the support of the DFG priority program SPP 1992 "Exploring the Diversity of Extrasolar Planets" (JE 701/5-1). E.M. would also like to warmly thank the staff at the Hamburger Sternwarte for their hospitality during his stay funded by project EST18/00162. Based on data from the CARMENES data archive at CAB (INTA-CSIC).Peer reviewe

    RICORS2040 : The need for collaborative research in chronic kidney disease

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    Chronic kidney disease (CKD) is a silent and poorly known killer. The current concept of CKD is relatively young and uptake by the public, physicians and health authorities is not widespread. Physicians still confuse CKD with chronic kidney insufficiency or failure. For the wider public and health authorities, CKD evokes kidney replacement therapy (KRT). In Spain, the prevalence of KRT is 0.13%. Thus health authorities may consider CKD a non-issue: very few persons eventually need KRT and, for those in whom kidneys fail, the problem is 'solved' by dialysis or kidney transplantation. However, KRT is the tip of the iceberg in the burden of CKD. The main burden of CKD is accelerated ageing and premature death. The cut-off points for kidney function and kidney damage indexes that define CKD also mark an increased risk for all-cause premature death. CKD is the most prevalent risk factor for lethal coronavirus disease 2019 (COVID-19) and the factor that most increases the risk of death in COVID-19, after old age. Men and women undergoing KRT still have an annual mortality that is 10- to 100-fold higher than similar-age peers, and life expectancy is shortened by ~40 years for young persons on dialysis and by 15 years for young persons with a functioning kidney graft. CKD is expected to become the fifth greatest global cause of death by 2040 and the second greatest cause of death in Spain before the end of the century, a time when one in four Spaniards will have CKD. However, by 2022, CKD will become the only top-15 global predicted cause of death that is not supported by a dedicated well-funded Centres for Biomedical Research (CIBER) network structure in Spain. Realizing the underestimation of the CKD burden of disease by health authorities, the Decade of the Kidney initiative for 2020-2030 was launched by the American Association of Kidney Patients and the European Kidney Health Alliance. Leading Spanish kidney researchers grouped in the kidney collaborative research network Red de Investigación Renal have now applied for the Redes de Investigación Cooperativa Orientadas a Resultados en Salud (RICORS) call for collaborative research in Spain with the support of the Spanish Society of Nephrology, Federación Nacional de Asociaciones para la Lucha Contra las Enfermedades del Riñón and ONT: RICORS2040 aims to prevent the dire predictions for the global 2040 burden of CKD from becoming true

    Search for supersymmetry with a compressed mass spectrum in the vector boson fusion topology with 1-lepton and 0-lepton final states in proton-proton collisions at √s = 13 TeV

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