450 research outputs found

    Screening of herbicides in grain legumes: pre-emergence herbicides in faba beans

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    Ante la escasez de herbicidas autorizados en leguminosas, se realizaron dos ensayos en habas con 10 herbicidas elegidos por estar autorizados en otras leguminosas o en otros países. Ninguno de los productos resultó totalmente eficaz y selectivo. Algunos de los herbicidas de preemergencia autorizados en España en habas para grano resultaron menos eficaces contra las malas hierbas y produjeron mayor fitotoxicidad que otros no autorizados. Así mismo, productos autorizados en Francia resultaron fitotóxicos en nuestras condiciones. Los mejores resultados seguido de ixosaben y aclonifen. Sin embargo será necesario ajustar dosis y buscar otras alternativas, como combinaciones de productos o estrategias de control para mejorar las eficacias y la selectividad, y sobre todo elegir los productos en función de las especies de malas hierbas dominantes en cada finca.Faced with a shortage of herbicides in legumes, two trials were conducted in faba beans to evaluate 10 herbicides elected by being authorized in other legumes or in other countries. None of the product was completely effective and selective. Some of the pre-emergence herbicides authorized in Spain for grain faba beans were less effective against weeds and produced more phytotoxicity than others not authorized. Likewise, products authorized in France turned out quite phytotoxic in our conditions. The best results were obtained with metribuzin by its effective weed control and low phytotoxicity, followed by ixosaben and aclonifen. However it will be necessary to adjust dose, to look for other alternatives, such as combinations of products or control strategies to improve effectiveness and selectivity, and above all choose the products depending on the species of dominant weeds in each farm

    Intercomparison of spectroradiometers and Sun photometers for the determination of the aerosol optical depth during the VELETA-2002 field campaign

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    [ 1] In July 2002 the VELETA-2002 field campaign was held in Sierra Nevada ( Granada) in the south of Spain. The main objectives of this field campaign were the study of the influence of elevation and atmospheric aerosols on measured UV radiation. In the first stage of the field campaign, a common calibration and intercomparison between Licor-1800 spectroradiometers and Cimel-318 Sun photometers was performed in order to assess the quality of the measurements from the whole campaign. The intercomparison of the Licor spectroradiometers showed, for both direct and global irradiances, that when the comparisons were restricted to the visible part of the spectrum the deviations were within the instruments' nominal accuracies which allows us to rely on these instruments for measuring physical properties of aerosols at the different measurement stations. A simultaneous calibration on AOD data was performed for the Cimel-318 Sun photometers. When a common calibration and methodology was applied, the deviation was lowered to much less than 0.01 for AOD. At the same time an intercomparison has been made between the AOD values given by the spectroradiometers and the Sun photometers, with deviations obtained from 0.01 to 0.03 for the AOD in the visible range, depending on the channel. In the UVA range, the AOD uncertainty was estimated to be around 0.02 and 0.05 for Cimel and Licor respectively. In general the experimental differences were in agreement with this uncertainty estimation. In the UVB range the AOD measurements should not be used due to maximum instrumental uncertainties

    Synthesis and characterization of a-Fe2O3 nanoparticles showing potential applications for sensing quaternary ammonium vapor at room temperature

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    P-Type and n-Type metal oxide semiconductors are widely used in the manufacture of gas sensing materials, due to their excellent electronic, electrical and electrocatalytic properties. Hematite (?-Fe2O3) compound has been reported as a promising material for sensing broad types of gases, due to its affordability, good stability and semiconducting properties. In the present work, the efficient and easy-To-implement sol-gel method has been used to synthesize ?-Fe2O3 nanoparticles (NPs). The TGA-DSC characterizations of the precursor gel provided information about the phase transformation temperature and the mass percentage of the hematite NPs. X-ray diffraction, transmission electron microscopy and x-ray photoelectron spectroscopy data analyses indicated the formation of two iron oxide phases (hematite and magnetite) when the NPs are subjected to thermal treatment at 400 °C. Meanwhile, only the hematite phase was determined for thermal annealing above 500 °C up to 800 °C. Besides, the crystallite size shows an increasing trend with the thermal annealing and no defined morphology. A clear reduction of surface defects, associated with oxygen vacancies was also evidenced when the annealing temperature was increased, resulting in changes on the electrical properties of hematite NPs. Resistive gas-sensing tests were carried out using hematite NPs + glycerin paste, to detect quaternary ammonium compounds. Room-Temperature high sensitivity values (S r ?4) have been obtained during the detection of 1/41 mM quaternary ammonium compounds vapor. The dependence of the sensitivity on the particle size, the mass ratio of NPs with respect to the organic ligand, changes in the dielectric properties, and the electrical conduction mechanism of gas sensing was discussed

    Activated protein C, severe sepsis and 28-day mortality

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    Protein C (PC) de ciency is prevalent in severe sepsis, studies showing that more than 80% of patients with severe sepsis have a baseline PC level below the lower limit of normal [1,2]. The aim of the study was to relate the anticoagulation activity evaluated by PC, with clinical parameters and 28-day mortality.Ye

    A tool for predicting the dynamic response of biotrickling filters for VOC removal

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    This article presents the development of a MATLAB® computer program to simulate the performance of biotrickling filters. Since these filters behave differently during spraying and nonspraying cycles, the presented simulation tool is built on top of a mathematical description of each situation. The resulting variable-structure model is then used as the basis for simulation experiments. The model presented herein represents the first attempt to take into account the variable spraying pattern usually found in industrial installations. Overall, the software is flexible and easy to use, allowing the user to specify the emission concentration pattern, the gas concentration pattern, as well as the spraying cycle periods for up to two different emission patterns per day. The model is able to predict experimental data from a biotrickling filter treating isopropanol under intermittent conditions of loading and spraying. Simulation examples are then provided to study the effect of variable inlet concentrations and gas flow rates

    Evolución de la innovación educativa en la Universidad Complutense: proyecto UNICOMEX

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    La evolución de la educación universitaria en España ha experimentado una enorme evolución en los últimos veinte años. Desde la enseñanza centrada en la clase magistral, con el consiguiente protagonismo del profesor, a lo que sucede actualmente, con el estudiante como eje principal, media todo un cambio en el planteamiento de nuestro sistema educativo universitario. La implantación del Espacio Europeo de Educación Superior (EEES) ha sido uno de los objetivos perseguidos por la Universidad Complutense de Madrid (UCM) en la última década. Con este fin existieron, hasta hace poco, las conocidas como Asignaturas Piloto (AP) e igualmente se convocan periódicamente, desde hace años, los Proyectos de Innovación Educativa (P.I.E.). Ambas herramientas han procurado facilitar dicha adaptación, así como promover un concepto transversal en la transmisión del conocimiento. Nuestro grupo de trabajo puede ser un ejemplo de lo que la UCM ha querido conseguir con ambas cosas. La asignatura ha participado en todas las convocatorias de AP, pasando por una evolución clara desde la clase magistral a los pequeños grupos de trabajo. Ha sido, además, el instrumento útil para ir desarrollando distintos P.I.E., hasta un total de nueve, tras formar un equipo interdisciplinar constituido por profesores universitarios y profesionales de diversos ámbitos. El último de estos PIE, concedido en el curso académico 2011-2012, consiste en la creación de un espacio virtual de referencia para el estudio de los animales exóticos, partiendo de los resultados obtenidos en proyectos anteriores. UNICOMEX (Universidad-Complutense-Exóticos) nace con el objetivo de poner al alcance de cualquiera una serie de recursos virtuales ordenados que faciliten el conocimiento biológico, anatómico y clínico de los animales exóticos, entendiendo como tales aquellos que, siendo de interés veterinario, no se consideran domésticos. La totalidad de su contenido está en español e inglés, con el fin de hacer de ella una herramienta virtual útil y abierta a la comunidad científica y didáctica internacional

    Spectroscopy of 18^{18}Na: Bridging the two-proton radioactivity of 19^{19}Mg

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    The unbound nucleus 18^{18}Na, the intermediate nucleus in the two-proton radioactivity of 19^{19}Mg, was studied by the measurement of the resonant elastic scattering reaction 17^{17}Ne(p,17^{17}Ne)p performed at 4 A.MeV. Spectroscopic properties of the low-lying states were obtained in a R-matrix analysis of the excitation function. Using these new results, we show that the lifetime of the 19^{19}Mg radioactivity can be understood assuming a sequential emission of two protons via low energy tails of 18^{18}Na resonances

    Aerosol properties derived from ground-based Fourier transform spectra within the COllaborative Carbon Column Observing Network

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    Fourier transform infrared (FTIR) spectroscopy is particularly relevant for climate studies due to its ability to provide information on both fine absorption structures (i.e. trace gases) and broadband continuum signatures (i.e. aerosols or water continuum) across the entire infrared (IR) domain. In this context, this study assesses the capability of the portable and compact EM27/SUN spectrometer, used within the research infrastructure COCCON (COllaborative Carbon Column Observing Network), to retrieve spectral aerosol properties from low-resolution FTIR solar absorption spectra (0.5 cm−1). The study focuses on the retrieval of aerosol optical depth (AOD) and its spectral dependence in the 873–2314 nm spectral range from COCCON measurements at the subtropical high-mountain Izaña Observatory (IZO, Tenerife, Spain), which were coincidentally carried out with standard sun photometry within the Aerosol Robotic Network (AERONET) in the 3-year period from December 2019 to September 2022. The co-located AERONET–COCCON database was used to cross-validate these two independent techniques in the common spectral range (870–1640 nm), demonstrating an excellent agreement at the near-coincident spectral bands (mean AOD differences limited to 0.005, standard deviations up to 0.021 and Pearson regression coefficients up to 0.97). This indicates that the low-resolution COCCON instruments are suitable for detecting the aerosol broadband signal contained in the IR spectra in addition to the retrieval of precise trace gas concentrations, provided a robust calibration procedure (Langley-based or absolute calibration procedures) is used to compensate for the optical degradation of the external system (∼ 0.72 % per month). The study also assesses the capability of the EM27/SUN to simultaneously infer aerosols and trace gases and relate their common emission sources in two case study events: a volcanic plume from the La Palma eruption in 2021 and a nearby forest fire in Tenerife in 2022. Overall, our results demonstrate the potential of the portable low-resolution COCCON instruments to enhance the multi-parameter capability of the FTIR technique for atmospheric monitoring.</p
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