114 research outputs found

    The antenna DSA 3 and its potential use for Radio Astronomy

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    The European Space Agency (ESA) will inaugurate its third Deep Space Antenna (DSA 3) by the end of 2012. DSA 3 will be located in Argentina near the city of Malarg"ue in the Mendoza province. While the instrument will be primarily dedicated to communications with interplanetary missions, the characteristics of its antenna and receivers will also enable standalone leading scientific contributions, with a high scientific-technological return. We outline here scientific proposals for a radio astronomical use of DSA 3.Comment: 4 pages, submitted as Proceedings for the BAA

    Diamond forms during low pressure serpentinisation of oceanic lithosphere

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    Diamond is commonly regarded as an indicator of ultra-high pressure conditions in Earth System Science. This canonical view is challenged by recent data and interpretations that suggest metastable growth of diamond in low pressure environments. One such environment is serpentinisation of oceanic lithosphere, which produces highly reduced CH4-bearing fluids after olivine alteration by reaction with infiltrating fluids. Here we report the first ever observed in situ diamond within olivine-hosted, CH4-rich fluid inclusions from low pressure oceanic gabbro and chromitite samples from the Moa-Baracoa ophiolitic massif, eastern Cuba. Diamond is encapsulated in voids below the polished mineral surface forming a typical serpentinisation array, with methane, serpentine and magnetite, providing definitive evidence for its metastable growth upon low temperature and low pressure alteration of oceanic lithosphere and super-reduction of infiltrated fluids. Thermodynamic modelling of the observed solid and fluid assemblage at a reference P-T point appropriate for serpentinisation (350 °C and 100 MPa) is consistent with extreme reduction of the fluid to logfO2 (MPa) = −45.3 (ΔlogfO2[Iron-Magnetite] = −6.5). These findings imply that the formation of metastable diamond at low pressure in serpentinised olivine is a widespread process in modern and ancient oceanic lithosphere, questioning a generalised ultra-high pressure origin for ophiolitic diamond.European Union (EU)Spanish Projects CGL2015-65824 RTI2018-099157-A-I00 PID2019-105625RB-C21 A.RNM.186.UGR18Spanish Government RYC-2015-17596Mexican research program CONACYT-Ciencia Basica A1-S-14574Mexican research program UNAM-PAPIIT IA-10141

    PARTICULAS FINAS EN EL AIRE DE LOCALES GASTRONOMICOS CON PARRILLA

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    La exposición a humo ambiental en lugares cerrados es peligrosa para la salud. Las partículas de hasta 2,5 micras son marcadores del humo en los lugares cerrados. Este estudio monitoreó la calidad de aire en 4 locales gastronómicos de Asunción, Paraguay, y algunas condiciones que influyen en los niveles de exposición explorados. Los niveles más altos de partículas encontrados fueron 9,9 μg/m3. En ninguno de los locales estudiados se detectaron fumadores. Falta mayor investigación sobre contaminación del aire en lugares cerrados para una mejor protección de la salud

    An Alternative Scenario on the Origin of Ultra-High Pressure (UHP) and Super-Reduced (SuR) Minerals in Ophiolitic Chromitites: A Case Study from the Mercedita Deposit (Eastern Cuba)

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    The origin of the assemblage of ultra-high pressure (UHP), super-reduced (SuR) and several crustally derived phases in ophiolitic chromitites is still hotly debated. In this paper, we report, for the first time, this assemblage of phases in ophiolitic chromitites of the Caribbean. We studied the Mercedita chromitite deposit in the eastern Cuban ophiolitic complexes. The mineral phases were characterized using microRaman spectroscopy, energy-dispersive spectroscopy with a scanning electron microscope (SEM-EDS), X-ray microdiffraction and electron microprobe analyses. Mineral concentrates were prepared using hydroseparation techniques. We have identified oriented clinopyroxene lamellae in chromite, oriented rutile lamellae in chromite, moissanite hosted in the altered matrix of the chromitite, graphite-like amorphous carbon, corundum and SiO2 hosted in healed fractures in chromite grains, and native Cu and Fe–Mn alloy recovered in heavy-mineral concentrates obtained by hydroseparation. This assemblage may correspond to UHP-SuR conditions, implying recycling of chromitite in the mantle or formation of the chromite grains at deep mantle depths, followed by emplacement at a shallow level in the mantle. However, the chromitite bodies contain gabbro sills oriented parallel to the elongation of the chromitite lenses, and these show no evidence of HP/UHP metamorphism. Therefore, the identified “exotic” phases may not be indicative of UHP. They formed independently as oriented clinopyroxene lamellae in chromite during cooling (clinopyroxene and rutile), in super-reduced microenvironments during the serpentinization processes, and by transference of subducted crustal material to the mantle wedge via cold plumes.This research was financially supported by the Spanish Project CGL2015-65824 granted by the Spanish “Ministerio de Economía y Competitividad” to J.A.P., the Ramón y Cajal Fellowship RYC-2015-17596 to J.M.G.-J. and a FPU Ph.D grant to N.P.-S. by the Ministerio de Educación of the Spanish Government

    Análisis de ácidos grasos en grasa subcutánea procedentes de animales de alimentación fiable y segura

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    Iberian pig fat characteristics depend on the type of feeding at the end of its finish-fattening period. The routine analysis to differentiate among the qualities of the feeding types given to the pigs in the fattening stage has been the use of fatty acid profiles by gas chromatography. Due to de doubts about the effectiveness of this analysis in the montanera period, the aim of this global study was to test the validity of various analytical methods to determine the feeding type of Iberian pigs, focusing on the fatty acid profile. Three montanera periods with a total of 749 samples from 38 batches have been studied; using a total of 144 dry-cured shoulder shanks, 99 of which are of known pig origin. Results showed that the determination of the fatty acid profile using gas chromatography is not a consistent method to classify the animals according to diet in the recebo category, although it provided good percentages of success for classifying the bellota and cebo categories.Las características de la grasa de cerdo Ibérico dependen del tipo de alimentación recibida en el último estadío de engorde. El análisis que se ha utilizado hasta ahora para diferenciar las diferentes calidades de alimentación de los cerdos en este período ha sido el análisis de los perfiles de ácidos grasos de la grasa por técnicas de cromatografía de gases. Debido a las dudas sobre la efectividad de esta técnica en la montanera, el objetivo del proyecto global (RTA2008-0026) fue probar la validez de varios métodos analíticos para determinar el tipo de alimentación del cerdo ibérico, centrándonos en este trabajo en el estudio de los perfiles de ácidos grasos. Para el desarrollo de este estudio se utilizaron tres campañas de montanera con un total de 749 muestras de 38 partidas, y con 144 paletas de las cuales 99 tenían una trazabilidad completa. Los resultados mostraron que la determinación de la alimentación de los cerdos ibéricos usando el análisis del perfil de ácidos grasos no es un método consistente para clasificar los animales de acuerdo a la categoría de recebo, mientras que para las categorías de bellota y cebo, los resultados encontrados mostraron unos buenos porcentajes de éxito

    Modelos experimentales de anuros para estudiar los efectos de piretroides.

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    Los ecosistemas acuáticos están cada vez más expuestos a numerosos contaminantes ambientales, como los agroquímicos. En los últimos años se ha observado que los tests de toxicidad sólo evalúan los efectos a corto plazo (mortalidad) y no son suficientes para evaluar los riesgos de los ecosistemas. Por esta razón, son muy importantes las evaluaciones a largo plazo, ya que permiten estimar la incidencia de estos cambios sobre la biodiversidad y la salud humana. En el presente artículo evaluamos estadísticamente, bajo condiciones de laboratorio, el efecto agudo (mortalidad – supervivencia), las dosis subcrónicas (tasa de crecimiento y desarrollo) y las alteraciones a nivel subcelular e histológico, producidos por el pesticida cipermetrina. Los bioensayos de toxicidad fueron realizados con embriones y larvas de estadios críticos de dos especies regionales de anuros: Physalaemus biligonigerus y Bufo arenarum. Estas especies fueron elegidas debido a su sensibilidad a los biocidas y a su importancia ecológica. Adicionalmente, se realizó un análisis morfológico de los órganos target por microscopía óptica y electrónica, para evaluar el desarrollo de mecanismos adaptativos a las nuevas condiciones desfavorables. Se realizaron en forma complementaria estudios de in situ TUNEL y morfometría.Fil: Izaguirre, María Fernanda. Universidad Nacional de Entre Ríos. Facultad de Ingeniería. Departamento de Biología. Laboratorio de Microscopía; ArgentinaFil: Marín, L.. Universidad Nacional de Entre Ríos. Facultad de Ingeniería. Departamento de Biología. Laboratorio de Microscopía; ArgentinaFil: Vergara, M. N.;. Universidad Nacional de Entre Ríos. Facultad de Ingeniería. Departamento de Biología. Laboratorio de Microscopía; ArgentinaFil: Lajmanovich, Rafael Carlos. Instituto Nacional de Limnología (inali-conicet),; ArgentinaFil: Peltzer, Paola. Instituto Nacional de Limnología (inali-conicet),; ArgentinaFil: Casco, Victor Hugo. Universidad Nacional de Entre Ríos. Facultad de Ingeniería. Departamento de Biología. Laboratorio de Microscopía; Argentin

    ERP evidence suggests executive dysfunction in ecstasy polydrug users

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    Background: Deficits in executive functions such as access to semantic/long-term memory have been shown in ecstasy users in previous research. Equally, there have been many reports of equivocal findings in this area. The current study sought to further investigate behavioural and electro-physiological measures of this executive function in ecstasy users. Method: Twenty ecstasy–polydrug users, 20 non-ecstasy–polydrug users and 20 drug-naïve controls were recruited. Participants completed background questionnaires about their drug use, sleep quality, fluid intelligence and mood state. Each individual also completed a semantic retrieval task whilst 64 channel Electroencephalography (EEG) measures were recorded. Results: Analysis of Variance (ANOVA) revealed no between-group differences in behavioural performance on the task. Mixed ANOVA on event-related potential (ERP) components P2, N2 and P3 revealed significant between-group differences in the N2 component. Subsequent exploratory univariate ANOVAs on the N2 component revealed marginally significant between-group differences, generally showing greater negativity at occipito-parietal electrodes in ecstasy users compared to drug-naïve controls. Despite absence of behavioural differences, differences in N2 magnitude are evidence of abnormal executive functioning in ecstasy–polydrug users

    Potential use of near-infrared spectroscopy to predict fatty acid profile of meat from different european autochthonous pig breeds

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    Autochthonous pig breeds provide products of differentiated quality, among which quality control is difficult to perform and insufficient for current market requirements. The present research evaluates the predictive ability of near?infrared (NIR) spectroscopy, combined with chemometric methods as a rapid and affordable tool to assure traceability and quality control. Thus, NIR technology was assessed for intact and minced muscle Longissimus thoracis et lumborum samples collected from 12 European autochthonous pig breeds for the quantification of lipid content and fatty acid composition. Different tests were performed using different numbers of samples for calibration and validation. The best predictive ability was found using minced presentation and set with 80% of the samples for the calibration and the remaining 20% for the external validation test for the following traits: lipid content and saturated and polyunsaturated fatty acids, which attained both the highest determination coefficients (0.89, 0.61, and 0.65, respectively) and the lowest root mean square errors in external validation (0.62, 1.82, and 1.36, respectively). Lower predictive ability was observed for intact muscles. These results could contribute to improve the management of autochthonous breeds and to ensure quality of their products by traditional meat industry chains.FE1B-06B2-126F | Jos? Pedro Pinto de Ara?joN/

    Predicción del Índice de Reposición en Montanera para la clasificación de canales de cerdo Ibérico según régimen alimenticio mediante el análisis no destructivo por Espectroscopía del Infrarrojo Cercano

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    The classification of Iberian pig carcasses into different commercial categories according to feeding regime was evaluated by means of a non-destructive analysis of the subcutaneous adipose tissue using Near Infrared Spectroscopy (NIRS). A quantitative approach was used to predict the Acorn-Grass Weight Gain Index (AGWGI), and a set of criteria was established for commercial classification purposes. A total of 719 animals belonging to various batches, reflecting a wide range of feeding regimes, production systems and years, were analyzed with a view to developing and evaluating quantitative NIRS models. Results for the external validation of these models indicate that NIRS made clear differentiation of batches as a function of three feeding regimes possible with high accuracy (Acorn, Recebo and Feed), on the basis of the mean representative spectra of each batch. Moreover, individual analysis of the animals showed a broad consensus between field inspection information and the classification based on the AGWGI NIRS prediction, especially for extreme categories (Acorn and Feed).La clasificación en distintas categorías comerciales según régimen alimenticio de canales de cerdo Ibérico fue evaluada mediante el análisis no destructivo de muestras de tejido adiposo subcutáneo por Espectroscopía del Infrarrojo Cercano (NIRS). Partiendo de una aproximación cuantitativa para predecir el Índice de Reposición en Montanera (IRM) se establecieron una serie de criterios para proceder a su clasificación comercial. Se analizaron un total de 719 animales pertenecientes a diversas partidas, que recogen una amplia variabilidad de muestras de distintos regímenes alimenticios, campañas y sistemas productivos, para el desarrollo y evaluación de los modelos NIRS cuantitativos. Los resultados de validación externa de los modelos indicaron que es posible discriminar con una gran exactitud entre partidas de distintos categorías (Bellota, Recebo y Cebo), en base al espectro medio representativo de cada partida. Además, el análisis individualizado de los animales mostró un amplio consenso entre la información recibida de campo y la clasificación en base a la predicción del parámetro IRM por NIRS, sobre todo para categorías con características extremas (Bellota y Cebo)
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