79 research outputs found

    A domain decomposition multiscale mixed method for flow in porous media based on Robin boundary conditions

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    In this work we propose a domain decomposition method based on Robin type boundary con- ditions that is suitable to solve the porous media equations on very large reservoirs. In order to reduce the algebraic systems to be solved to affordable sizes, a multiscale formulation is considered in which the coupling variables between subdomains, namely, pressures and normal fluxes, are seek in low dimen- sional spaces on the skeleton of the decomposition, while considering the permeability heterogeneities in the original fine grid for the local problems. In the new formulation, a non-dimensional parameter in the Robin condition is introduced such that we may transit smoothly from two well known formulations, namely, the Multiscale Mortar Mixed and the Multiscale Hybrid Mixed finite element methods. In the proposed formulation the interface spaces for pressure and fluxes can be selected independently. This has the potential to produce more accurate results by better accommodating local features of the exact solution near subdomain boundaries. Several numerical examples which exhibit highly heterogeneous permeability fields and channelized regions are solved with the new formulation and results compared to the aforementioned multiscale methods.Publicado en: Mecánica Computacional vol. XXXV, no. 17Facultad de Ingenierí

    A domain decomposition multiscale mixed method for flow in porous media based on Robin boundary conditions

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    In this work we propose a domain decomposition method based on Robin type boundary con- ditions that is suitable to solve the porous media equations on very large reservoirs. In order to reduce the algebraic systems to be solved to affordable sizes, a multiscale formulation is considered in which the coupling variables between subdomains, namely, pressures and normal fluxes, are seek in low dimen- sional spaces on the skeleton of the decomposition, while considering the permeability heterogeneities in the original fine grid for the local problems. In the new formulation, a non-dimensional parameter in the Robin condition is introduced such that we may transit smoothly from two well known formulations, namely, the Multiscale Mortar Mixed and the Multiscale Hybrid Mixed finite element methods. In the proposed formulation the interface spaces for pressure and fluxes can be selected independently. This has the potential to produce more accurate results by better accommodating local features of the exact solution near subdomain boundaries. Several numerical examples which exhibit highly heterogeneous permeability fields and channelized regions are solved with the new formulation and results compared to the aforementioned multiscale methods.Publicado en: Mecánica Computacional vol. XXXV, no. 17Facultad de Ingenierí

    A domain decomposition multiscale mixed method for flow in porous media based on Robin boundary conditions

    Get PDF
    In this work we propose a domain decomposition method based on Robin type boundary con- ditions that is suitable to solve the porous media equations on very large reservoirs. In order to reduce the algebraic systems to be solved to affordable sizes, a multiscale formulation is considered in which the coupling variables between subdomains, namely, pressures and normal fluxes, are seek in low dimen- sional spaces on the skeleton of the decomposition, while considering the permeability heterogeneities in the original fine grid for the local problems. In the new formulation, a non-dimensional parameter in the Robin condition is introduced such that we may transit smoothly from two well known formulations, namely, the Multiscale Mortar Mixed and the Multiscale Hybrid Mixed finite element methods. In the proposed formulation the interface spaces for pressure and fluxes can be selected independently. This has the potential to produce more accurate results by better accommodating local features of the exact solution near subdomain boundaries. Several numerical examples which exhibit highly heterogeneous permeability fields and channelized regions are solved with the new formulation and results compared to the aforementioned multiscale methods.Publicado en: Mecánica Computacional vol. XXXV, no. 17Facultad de Ingenierí

    Combinations of Metarhizium anisopliae with chemical insecticides and their effectiveness in Mahanarva fimbriolata (Hemiptera: Cercopidae) control on sugarcane

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    Some insecticides can be used jointly with entomopathogenic fungi, and therefore the combi- nation of chemical and biological control measures can be a safe and effective method to con- trol insect pests. The aim of this study was to evaluate the costs and efficacy of combinations of Metarhizium anisopliae (Metschnikoff) Sorokin (Hypocreales: Clavicipitaceae) with thiameth- oxam and imidacloprid on spittlebug (Mahanarva fimbriolata (Stål); Hemiptera: Cercopidae) control on sugarcane. The experiment was conducted as a randomized block design (RBD) with 10 treatments and 4 replications. The treatments included a control (untreated), thia- −1 −1 12 −1 methoxam (250 g ha ), imidacloprid (700 g ha ), M. anisopliae (M. a.) (3 × 10 conidia ha ), A1 (3 × 10 12 M. a. conidia ha −1 + 65 g ha −1 of thiamethoxam), A2 (3 × 10 12 M. a. conidia ha −1 + 125 g ha −1 of thiamethoxam), A3 (3 × 10 12 M. a. conidia ha −1 + 187.5 g ha −1 of thiamethoxam), A4 (3 × 10 12 M. a. conidia ha −1 + 175 g ha −1 of imidacloprid), A5 (3 × 10 12 M. a. conidia ha −1 + 350 g ha −1 of imidacloprid), and A6 (3 × 10 12 M. a. conidia ha −1 + 525g ha −1 of imidacloprid). The reductions in the numbers of M. fimbriolata nymphs per treatment compared to the control were similar at 15 DAT (days after treatment) in all treatments except combination A5 (M. anisopliae and thiamethoxam). At 30 DAT, the numbers of nymphs were significantly reduced in all treatments except A3, and their effectiveness ranged from 14.28% to 92.85%. At 45 DAT the numbers of M. fimbriolata nymphs per treatment were significantly reduced in the following treatments: imidacloprid alone at 700g ha -1 , A1, A2, A3, A4 and A6; and the combinations A1 and A2 caused the lowest M. fimbriolata nymph infestations and effectiveness rates of 77.41 and 87.09 %, respectively. At 75 DAT the 2 best control efficacies occurred in treatments A1 (3 × 10 12 M. a. conidia ha -1 of + 65g ha -1 of thiamethoxam) (82.1%) and A5 (78.6%) (3 × 10 12 M. a. conidia ha −1 + 350 g ha −1 of imidacloprid). At 90 DAT the number of nymphs in the control had increased 2.8 fold over the number at 75 DAT. Very good control efficacies at 90 DAT occurred in all treatments with the combination of the fungus with an insecticide. At 105 DAT the numbers of nymphs had surged in all treatments, and no treatment provided effective control. The treatments with the highest earnings per hectare were A1 (3 × 10 12 M. a. conidia ha -1 + 65 g thiamethoxam) and M. anisopliae alone at the recommended dose of 3 × 10 12 M. a. conidia ha -1 . Our findings demonstrate the effectiveness of using either thiamethoxam or imidacloprid in combination with M. anisopliae to control M. fimbriolata nymphs on sugarcane, but greater net earnings per hectare occurred with the lowest rate of the thiamethoxam combination than with any of the imidacloprid combinations.Algunos insecticidas se puede utilizar con hongos entomopatógenos y por lo tanto, la aso- ciación de los controles químico y biológico puede ser una estrategia segura y eficaz para el control de insectos-plaga. El objetivo de este estudio fue evaluar los costos y eficacia de combinaciones de Metarhizium anisopliae (Metschnikoff) Sorokin (Hypocreales: Clavi- cipitaceae) con insecticidas thiamethoxam e imidacloprid para el control de la chicharrita (Mahanarva fimbriolata (Stål); Hemiptera: Cercopidae) en caña de azúcar . El experimento fue conducido en un delineamiento en bloques casualizados (DBC), con 10 tratamientos y 4 repeticiones. Los tratamientos que incluidos el control (sin tratamiento), thiamethoxam (250 g ha −1 ), imidacloprido (700 g ha −1 ), M. anisopliae (M.a.) (3×10 12 conidios ha −1 ), A1 (3×10 12 conidios ha −1 de M. a. + 65 g ha −1 de thiamethoxam), A2 (3×10 12 conidios ha −1 de M. a. + 125g ha −1 de thiamethoxam), A3 (3×10 12 conidios ha −1 de M. a. + 187.5 g ha −1 de thiamethoxam), A4 (3×10 12 conidios ha −1 de M.a + 175 g ha −1 de imidacloprido), A5 (3×10 12 conidios ha −1 de M. a. + 350 g ha −1 de imidacloprido) y A6 (3×10 12 conidios ha −1 de M. a. + 525g ha −1 de imidacloprido). Las reducciones en el número de ninfas M. fimbriolata por tratamiento en comparación con el control fueron similares a los 15 DAT (días pos tratamiento) en todos los tratamientos excepto A5 combinación (M. anisopliae y thiamethoxam). A los 30 DAT, el número de ninfas se redujeron significativamente en todos los tratamientos, excepto A3, y su eficacia varió de 14,28% para 92,85%. A los 45 DAT, los números de ninfas M. fimbriolata por tratamiento se redujeron significativamente en los siguientes tratamientos: imidacloprido solo en 700 g ha -1 , A1, A2, A3, A4 y A6; y las combinaciones de A1 y A2 causaron la más bajo infestaciones de ninfas M. fimbriolata y sus tasas de eficacia fueron de 77,41 y 87,09%, respectivamente. A los 75 DAT, los 2 mejores eficacias de control se produjeron en tratamientos A1 (3×10 12 conidios ha −1 de M. a. + 65 g ha −1 de thiamethoxam) y A5 (78.6%) (3×10 12 conidios ha −1 de M. a.+ 350 g ha −1 de imidacloprido). A los 90 DAT, el número de ninfas en el control había aumentado 2,8 veces más el número a 75 DAT. Muy buenas eficacias de control en 90 DAT, se produjo en todos los tratamientos con la combinación del hongo con un insecticida. A los 105 DAT, el número de ninfas habían aumentado en todos los tratamientos, y ningún tratamiento había proporcionado un control efectivo. Los tratamientos con los mayores rendimientos hectárea fueron A1 (3×10 12 conidios ha −1 de M. a.+ 65 g de thiamethoxam) y M. anisopliae solo a la dosis recomendada de 3×10 12 conidios ha −1 de M. a. Nuestros resultados demuestran la eficacia de thiamethoxam y imidacloprido en combinación con M. anisopliae para el control de ninfas M. fimbriolata en caña de azúcar, pero mayores beneficio neto por hectárea se produjeron con la tasa más baja de la combinación de thiamethoxam que con cualquiera de las combinaciones de imidacloprid

    Systematic analysis of jellyfish galaxy candidates in Fornax, Antlia, and Hydra from the S-PLUS survey: A self-supervised visual identification aid

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    © 2024 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/We study 51 jellyfish galaxy candidates in the Fornax, Antlia, and Hydra clusters. These candidates are identified using the JClass scheme based on the visual classification of wide-field, twelve-band optical images obtained from the Southern Photometric Local Universe Survey. A comprehensive astrophysical analysis of the jellyfish (JClass > 0), non-jellyfish (JClass = 0), and independently organized control samples is undertaken. We develop a semi-automated pipeline using self-supervised learning and similarity search to detect jellyfish galaxies. The proposed framework is designed to assist visual classifiers by providing more reliable JClasses for galaxies. We find that jellyfish candidates exhibit a lower Gini coefficient, higher entropy, and a lower 2D Sérsic index as the jellyfish features in these galaxies become more pronounced. Jellyfish candidates show elevated star formation rates (including contributions from the main body and tails) by 1.75 dex, suggesting a significant increase in the SFR caused by the ram-pressure stripping phenomenon. Galaxies in the Antlia and Fornax clusters preferentially fall towards the cluster's centre, whereas only a mild preference is observed for Hydra galaxies. Our self-supervised pipeline, applied in visually challenging cases, offers two main advantages: it reduces human visual biases and scales effectively for large data sets. This versatile framework promises substantial enhancements in morphology studies for future galaxy image surveys.Peer reviewe

    Adenosine A2A receptor as a potential regulator of Mycobacterium leprae survival mechanisms: new insights into leprosy neural damage

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    BackgroundLeprosy is a chronic infectious disease caused by Mycobacterium leprae, which can lead to a disabling neurodegenerative condition. M. leprae preferentially infects skin macrophages and Schwann cells–glial cells of the peripheral nervous system. The infection modifies the host cell lipid metabolism, subverting it in favor of the formation of cholesterol-rich lipid droplets (LD) that are essential for bacterial survival. Although researchers have made progress in understanding leprosy pathogenesis, many aspects of the molecular and cellular mechanisms of host–pathogen interaction still require clarification. The purinergic system utilizes extracellular ATP and adenosine as critical signaling molecules and plays several roles in pathophysiological processes. Furthermore, nucleoside surface receptors such as the adenosine receptor A2AR involved in neuroimmune response, lipid metabolism, and neuron–glia interaction are targets for the treatment of different diseases. Despite the importance of this system, nothing has been described about its role in leprosy, particularly adenosinergic signaling (AdoS) during M. leprae–Schwann cell interaction.MethodsM. leprae was purified from the hind footpad of athymic nu/nu mice. ST88-14 human cells were infected with M. leprae in the presence or absence of specific agonists or antagonists of AdoS. Enzymatic activity assays, fluorescence microscopy, Western blotting, and RT-qPCR analysis were performed. M. leprae viability was investigated by RT-qPCR, and cytokines were evaluated by enzyme-linked immunosorbent assay.ResultsWe demonstrated that M. leprae-infected Schwann cells upregulated CD73 and ADA and downregulated A2AR expression and the phosphorylation of the transcription factor CREB (p-CREB). On the other hand, activation of A2AR with its selective agonist, CGS21680, resulted in: 1) reduced lipid droplets accumulation and pro-lipogenic gene expression; 2) reduced production of IL-6 and IL-8; 3) reduced intracellular M. leprae viability; 4) increased levels of p-CREB.ConclusionThese findings suggest the involvement of the AdoS in leprosy neuropathogenesis and support the idea that M. leprae, by downmodulating the expression and activity of A2AR in Schwann cells, decreases A2AR downstream signaling, contributing to the maintenance of LD accumulation and intracellular viability of the bacillus
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