756 research outputs found

    Transform-based particle filtering for elliptic Bayesian inverse problems

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    We introduce optimal transport based resampling in adaptive SMC. We consider elliptic inverse problems of inferring hydraulic conductivity from pressure measurements. We consider two parametrizations of hydraulic conductivity: by Gaussian random field, and by a set of scalar (non-)Gaussian distributed parameters and Gaussian random fields. We show that for scalar parameters optimal transport based SMC performs comparably to monomial based SMC but for Gaussian high- dimensional random fields optimal transport based SMC outperforms monomial based SMC. When comparing to ensemble Kalman inversion with mutation (EKI), we observe that for Gaussian random fields, optimal transport based SMC gives comparable or worse performance than EKI depending on the complexity of the parametrization. For non-Gaussian distributed parameters optimal transport based SMC outperforms EKI

    Permittivity of (40 nm and 80 nm) alumina nanofluids in ethylene glycol at different temperatures

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    This article studies the effective permittivity of alumina nanofluids (aluminium oxide) in ethylene glycol. Two nanoparticle sizes (40 nm and 80 nm) were considered and the measurements were carried out at various concentrations (up to 2% in volume) and at six different temperatures (from 298.15 K to 348.15 K). An empirical equation is proposed that allows to obtain the permittivity value at any concentration or temperature in the studied ranges. The influence of the volume fraction, nanoparticle size and the temperature on relative permittivity is shown. When compared to the previous published values for alumina (40 nm) in water, current results show the influence of the base fluid. The enhancement of permittivity was calculated, and its behaviour was analysed. Smaller sized particles have the highest values of permittivity and enhancement. Theoretical models in the study of permittivity are applied. The poor predictions of classical models are attributed to the positive behaviour of the permittivity change on mixing for these nanofluids. The contributions to permittivity from ethylene glycol and nanoparticles are separated in two distinct terms in the variable index equation. The permittivity change on mixing calculated from this equation points out that the nanoparticles are the main responsible for the unusual permittivity increment in these colloids.We appreciate the financial support ED431C 2020-06 provided by the Xunta de Galicia (Spain). M.F.C. thanks Instituto Superior de Engenharia do Porto for granting leave of absence to carry out experimental work at University of Vigo.info:eu-repo/semantics/publishedVersio

    Single nucleotide polymorphism (SNP) analysis used for the phylogeny of the Mycobacterium tuberculosis complex based on a pyrosequencing assay

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    Background Different polymorphisms have been described as markers to classify the lineages of the Mycobacterium tuberculosis complex. The analysis of nine single nucleotide polymorphisms (SNPs) was used to describe seven SNPs cluster groups (SCGs). We attempted to classify those strains that could not been categorized into lineages by the genotyping methods used in the routine testing. Results The M. tuberculosis complex isolates collected in 2010 in our region were analysed. A new method based on multiplex-PCRs and pyrosequencing to analyse these SNPs was designed. For the pyrosequencing assay nine SNPs that defined the seven SCGs were selected from the literature: 1977, 74092, 105139, 232574, 311613, 913274, 2460626, 3352929 and gyrA95. In addition, SNPs in katG463, mgtC182, Ag85C103 and RDRio deletion were detected

    Preparation and degradation of rhodium and iridium diolefin catalysts for the acceptorless and base-free dehydrogenation of secondary alcohols

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    Rhodium and iridium diolefin catalysts for the acceptorless and base-free dehydrogenation of secondary alcohols have been prepared, and their degradation has been investigated, during the study of the reactivity of the dimers [M(µ-Cl)(I4-C8H12)]2 (M = Rh (1), Ir (2)) and [M(µ-OH)(I4-C8H12)]2 (M = Rh (3), Ir (4)) with 1, 3-bis(6'-methyl-2'-pyridylimino)isoindoline (HBMePHI). Complex 1 reacts with HBMePHI, in dichloromethane, to afford equilibrium mixtures of 1, the mononuclear derivative RhCl(I4-C8H12){¿1-Npy-(HBMePHI)} (5), and the binuclear species [RhCl(I4-C8H12)]2{µ-Npy, Npy-(HBMePHI)} (6). Under the same conditions, complex 2 affords the iridium counterparts IrCl(I4-C8H12){¿1-Npy-(HBMePHI)} (7) and [IrCl(I4-C8H12)]2{µ-Npy, Npy-(HBMePHI)} (8). In contrast to chloride, one of the hydroxide groups of 3 and 4 promotes the deprotonation of HBMePHI to give [M(I4-C8H12)]2(µ-OH){µ-Npy, Niso-(BMePHI)} (M = Rh (9), Ir (10)), which are efficient precatalysts for the acceptorless and base-free dehydrogenation of secondary alcohols. In the presence of KOtBu, the [BMePHI]- ligand undergoes three different degradations: Alcoholysis of an exocyclic isoindoline-N double bond, alcoholysis of a pyridyl-N bond, and opening of the five-membered ring of the isoindoline core.

    Monitoring spinach shelf-life with hyperspectral image through

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    Different procedures for monitoring the evolution of leafy vegetables, under plastic covers during cold storage, have been studied. Fifteen spinach leaves were put inside Petri dishes covered with three different plastic films and stored at 4 °C for 21 days. Hyperspectral images were taken during this storage. A radiometric correction is proposed in order to avoid the variation in transmittance of the plastic films during time in the hyperspectral images. Afterwards, three spectral pre-processing procedures (no pre-process, Savitsky–Golay and Standard Normal Variate, combined with Principal Component Analysis) were applied to obtain different models. The corresponding artificial images of scores were studied by means of Analysis of Variance to compare their ability to sense the aging of the leaves. All models were able to monitor the aging through storage. Radiometric correction seemed to work properly and could allow the supervision of shelf-life in leafy vegetables through commercial transparent films

    Antiangiogenic Therapy in Epithelial Ovarian Cancer

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    Approximately 75% of women with ovarian cancer are diagnosed at advanced stages (FIGO stage III/IV), with 15-23 months median global survival and 20% 5-year survival. Angiogenesis plays an important role in tumour development and proliferation. Increased angiogenesis is associated with worse clinical outcome in ovarian cancer. Here we review the play of bevacizumab in the treatment of ovarian cancer and also other antiangiogenic drugs. In total, to date there are no promising results for most of the reviewed antiangiogenic agents, except those already known for bevacizumab, trebananib, pazopanib, cediranib and nintedanib. Ongoing research will shed more light on this fascinating tumour process and its control

    Produzione, mercato e consumi della cerasicoltura spagnola

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    La crisi di sovrapproduzione di alcune specie tradizionali sta favorendo la crescita del ciliegio, che mostra un costante incremento delle superfici, favorito dal rinnovamento varietale, dall’aumento dei consumi, dal miglioramento delle tecnologie di produzione e dalla precocità di maturazione. Tutti fattori che garantiscono alla Spagna elevata competitività nelle esportazioni verso i Paesi dell’Ue.Colaboración en el blog: Rivista di frutticoltura e di ortofloricoltura. Disponible: http://www.rivistafrutticoltura.it

    Aplicación de imagen hiperespectral para observar el efecto de la salinidad en hojas de lechuga.

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    La salinización en suelos de cultivos es un fenómeno muy relevante en el Sureste español que se produce por el empleo de aguas de riego salinas o de mala calidad. La lechuga (Lactuca sativa L.) es uno de los cultivos hortícolas de mayor implantación en esta área, destinándose principalmente para consumo en fresco y en productos cuarta gama. La salinidad puede afectar a la productividad y calidad del cultivo, sin embargo, en determinadas concentraciones investigaciones previas muestran que la salinidad puede favorecer la conservación de las hojas tras el corte, disminuyendo los procesos de degradación enzimática y el desarrollo de microorganismos. El objetivo del presente trabajo es evaluar la viabilidad de la imagen hiperespectral (400 a 1000 nm) para identificar la influencia del estrés salino en lechuga ?baby? recién recolectada. Para ello, se han adquirido imágenes de 40 hojas de diferentes lechugas sometidas a tres soluciones salinas diferentes y a una solución control. Dichas imágenes fueron sometidas a preprocesado de espectros (suavizado con el algoritmo Savitsky-Golay + normalización SNV), combinado con Análisis de Componentes Principales. Las imágenes virtuales de scores generadas con el modelo muestran diferencias progresivas en los valores asignados a los píxeles de las imágenes a medida que aumenta la concentración salina de la solución aplicada al cultivo. Se observa cómo la solución salina afecta a la hoja cambiando la coloración de las zonas medias, posiblemente debido a la concentración de solutos. La interpretación de los loadings de estos modelos permite conocer cómo afecta la salinidad al comportamiento espectral de las hojas. La imagen hiperespectral puede tener un gran potencial para identificar los límites de salinidad tolerados y evitar concentraciones tóxicas que afecten negativamente la vida útil de las hortalizas de hoja. Este conocimiento permitirá desarrollar índices multiespectrales capaces de identificar hojas afectadas por salinidad durante su cultivo y procesado postcosecha

    Monitoring leafy vegetables through packaging films with

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    Fresh-cut or minimally processed fruit and vegetables have been physically modified from its original form (by peeling, trimming, washing and cutting) to obtain a 100% edible product that is subsequently packaged (usually under modified atmosphere packaging –MAP) and kept in refrigerated storage. In fresh-cut products, physiological activity and microbiological spoilage, determine their deterioration and shelf-life. The major preservation techniques applied to delay spoilage are chilling storage and MAP, combined with chemical treatments antimicrobial solutions antibrowning, acidulants, antioxidants, etc.). The industry looks for safer alternatives. Consequently, the sector is asking for innovative, fast, cheap and objective techniques to evaluate the overall quality and safety of fresh-cut products in order to obtain decision tools for implementing new packaging materials and procedures. In recent years, hyperspectral imaging technique has been regarded as a tool for analyses conducted for quality evaluation of food products in research, control and industries. The hyperspectral imaging system allows integrating spectroscopic and imaging techniques to enable direct identification of different components or quality characteristics and their spatial distribution in the tested sample. The objective of this work is to develop hyperspectral image processing methods for the supervision through plastic films of changes related to quality deterioration in packed readyto-use leafy vegetables during shelf life. The evolutions of ready-to-use spinach and watercress samples covered with three different common transparent plastic films were studied. Samples were stored at 4 ºC during the monitoring period (until 21 days). More than 60 hyperspectral images (from 400 to 1000 nm) per species were analyzed using ad hoc routines and commercial toolboxes of MatLab®. Besides common spectral treatments for removing additive and multiplicative effects, additional correction, previously to any other correction, was performed in the images of leaves in order to avoid the modification in their spectra due to the presence of the plastic transparent film. Findings from this study suggest that the developed images analysis system is able to deal with the effects caused in the images by the presence of plastic films in the supervision of shelf-life in leafy vegetables, in which different stages of quality has been identified

    Vegetative growth response of beets and lettuce to stored human urine

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    ArticleIn this work, we present the experimental results of the effect of stored human urine (SHU) on the growth of beets (Beta vulgaris L) and lettuce (Lactuca sativaL). We apply different amounts of SHU according to the recommended dose of nitrogen, considering soil from farmland and vermiculite as substrates. The last allows us to determine with high precision the isolated effect of SHU over the vegetative development of beet plants, without considering other nutrients present in common soils. Experimental results demonstrate that the application of SHU has no significant effects on lettuce vegetative growth under our soil conditions. In contrast, SHU can be used successfully as a fertilizer of beets. The optimum dose was found at 120kgN ha-1and resulted in average dry weight of 125g. However, if the dose exceeds the optimum levels, the growth of the plant is inhibited. Beets fertilized with SHU does not pose any hygienic risk for human consumption. Our findings represent a promising alternative to propose expanding the use of SHU as fertilizer in medium-sized greenhouses and to provide benefits to families in rural areas, with little or no available water supplies
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