1,148 research outputs found

    Implicit and implicit-explicit Lagrange-projection finite volume schemes exactly well-balanced for 1D shallow water system

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    In this paper we consider the Lagrange-Projection technique in the framework of finite volume schemes applied to the shallow water system. We shall consider two versions of the scheme for the Lagrangian step: one fully implicit and one implicit-explicit, based on how the geometric source term is treated. First and second order well-balanced versions of the schemes are presented, in which the water at rest solutions are preserved. This allows to obtain efficient numerical schemes in low Froude number regimes, as the usual CFL restriction driven by the acoustic waves is avoided.This work is partially supported by projects RTI2018-096064-B-C21 and RTI2018-096064-B-C22 funded by MCIN/AEI/10.13039/501100011033 and “ERDF A way of making Europe”, projects P18-RT-3163 of Junta de Andalucía and UMA18-FEDERJA-161 of Junta de Andalucía-FEDER-University of Málaga. C. Caballero-Cárdenas is supported by the grant FPI2019/087773 funded by MCIN/AEI/10.13039/501100011033 and “ESF Investing in your future”. // Funding for open access charge: Universidad de Málaga/CBUA

    On the influence of the thickness of the sediment moving layer in the definition of the bedload transport formula in Exner systems

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    In this paper we study Exner system and introduce a modified general definition for bedload transport flux. The new formulation has the advantage of taking into account the thickness of the sediment layer which avoids mass conservation problems in certain situations. Moreover, it reduces to a classical solid transport discharge formula in the case of quasi-uniform regime. We also present several numerical tests where we compare the proposed sediment transport formula with the classical formulation and we show the behavior of the new model in different configurations

    Workplace Learning Strategies and Professional Competencies in Innovation Contexts in Brazilian Hospitals

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    Competencies mobilized by service providers form an element of hospital services insofar as scientific and technological procedures that are part of the service become tangible. In view of the fact that hospitals have adopted Information and Communication Technologies (ICT), it would be logical to assume that learning contributes towards acquiring competencies related to changes in hospitals resulting from the adoption of new technologies. This paper aims to analyze relationships between workplace learning strategies and professional competencies after the adoption of innovations supported ICT in hospitals. Eleven interviews were carried out with professionals from three different hospitals and identifying the professional competencies resulting from innovations supported by ICT. This was followed by a cross-sectional survey involving 425 employees at the hospitals surveyed. The data analysis was undertaken by means of structural equation modeling (SEM). The results confirm the hypothesis and indicate that the performance of professional competences based on new ICT is determined by the way the respondents think, change and apply their knowledge, skills and attitudes in the workplace by use of new information and communication technologies

    An Efficient Two-Layer Non-hydrostatic Approach for Dispersive Water Waves

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    In this paper, we propose a two-layer depth-integrated non-hydrostatic system with improved dispersion relations. This improvement is obtained through three free parameters: two of them related to the representation of the pressure at the interface and a third one that controls the relative position of the interface concerning the total height. These parameters are then optimized to improve the dispersive properties of the resulting system. The optimized model shows good linear wave characteristics up to kH ≈ 10, that can be improved for long waves. The system is solved using an efficient formally second-order well-balanced and positive preserving hybrid finite volume/difference numerical scheme. The scheme consists of a two-step algorithm based on a projection-correction type scheme. First, the hyperbolic part of the system is discretized using a Polynomial Viscosity Matrix path-conservative finite-volume method. Second, the dispersive terms are solved using finite differences. The method has been applied to idealized and challenging physical situations that involve nearshore breaking. Agreement with laboratory data is excellent. This technique results in an accurate and efficient method

    First-principles calculation of intrinsic defect formation volumes in silicon

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    We present an extensive first-principles study of the pressure dependence of the formation enthalpies of all the know vacancy and self-interstitial configurations in silicon, in each charge state from -2 through +2. The neutral vacancy is found to have a formation volume that varies markedly with pressure, leading to a remarkably large negative value (-0.68 atomic volumes) for the zero-pressure formation volume of a Frenkel pair (V + I). The interaction of volume and charge was examined, leading to pressure--Fermi level stability diagrams of the defects. Finally, we quantify the anisotropic nature of the lattice relaxation around the neutral defects.Comment: 9 pages, 9 figure

    Dual augmentation for aerobic bioremediation of MTBE and TCE pollution in heavy metal-contaminated soil

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    In this work we isolated from soil and characterized several bacterial strains capable of either resisting high concentrations of heavy metals (Cd2+ or Hg2+ or Pb2+) or degrading the common soil and groundwater pollutants MTBE (methyl-tertbutyl ether) or TCE (trichloroethylene). We then used soil microcosms exposed to MTBE (50 mg/l) or TCE (50 mg/l) in the presence of one heavy metal (Cd 10 ppm or Hg 5 ppm or Pb 50 or 100 ppm) and two bacterial isolates at a time, a degrader plus a metalresistant strain. Some of these two-membered consortia showed degradation efficiencies well higher (49–182% higher) than those expected under the conditions employed, demonstrating the occurrence of a synergetic relationship between the strains used. Our results show the efficacy of the dual augmentation strategy for MTBE and TCE bioremediation in the presence of heavy metals

    Plantas invasoras no pantanal: como entender o problema e soluções de manejo por meio de diagnóstico participativo.

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    A invasão de espécies arbóreas e arbustivas em áreas de campos limpos tem diminuído a capacidade produtiva das fazendas, prejudicando o setor pecuário da região.Estas variações podem ser causadas por distúrbios naturais (ciclos plurianuais de cheia e seca e de manejo (fogo, taxa de lotação animal, método de controle/limpeza). Visando auxiliar no entendimento do problema e na busca de soluções sustentáveis, o Centro de Pesquisa do Pantanal (CPP), em parceria com a Embrapa Pantanal e a Universidade Federal de Mato Grosso (UFMT) realizaram o I Workshop da rede Pecuária, reunindo representantes de diversas instituições, fazendeiros de Poconé e todos os interessados. Este trabalho registrou as principais invasoras, as causas da invasão e as soluções de manejo definidas por produtores do Pantanal por meio da aplicação de diagnóstico participativo. As principais invasoras mencionadas foram: pombeiro (Combretum spp.), cambará(Vochysia divergens), conjiqueira (Byrsonima orbignyana) e lixeira (Curatella americana). As informações obtidas foram integradas com os conhecimentos científicos, para a definição de alternativas/soluções a curto, médio e longo prazo.bitstream/item/37290/1/BP66.pd

    Osificación Heterotópica Coxofemoral secundaria a Encefalitis Herpética : a propósito de un caso y revisión de la literatura

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    Heterotopic ossification is the abnormal formation of bone in soft tissues outside the skeleton. It is associated with nervous system injuries or after a hip replacement. It is therefore a relevant pathology against which there is a controversial diagnostic and therapeutic attitude. We report a case of a patient of 36 year who developed heterotopic ossification after herpetic encephalitis. We also review the published studies collecting the current recommendations for diagnosis, prevention and treatment

    Examination of the Feynman-Hibbs Approach in the Study of NeN_N-Coronene Clusters at Low Temperatures

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    Feynman-Hibbs (FH) effective potentials constitute an appealing approach for investigations of many-body systems at thermal equilibrium since they allow us to easily include quantum corrections within standard classical simulations. In this work we apply the FH formulation to the study of NeN_N-coronene clusters (N=N= 1-4, 14) in the 2-14 K temperature range. Quadratic (FH2) and quartic (FH4) contributions to the effective potentials are built upon Ne-Ne and Ne-coronene analytical potentials. In particular, a new corrected expression for the FH4 effective potential is reported. FH2 and FH4 cluster energies and structures -obtained from energy optimization through a basin-hoping algorithm as well as classical Monte Carlo simulations- are reported and compared with reference path integral Monte Carlo calculations. For temperatures T>4T> 4 K, both FH2 and FH4 potentials are able to correct the purely classical calculations in a consistent way. However, the FH approach fails at lower temperatures, especially the quartic correction. It is thus crucial to assess the range of applicability of this formulation and, in particular, to apply the FH4 potentials with great caution. A simple model of NN isotropic harmonic oscillators allows us to propose a means of estimating the cut-off temperature for the validity of the method, which is found to increase with the number of atoms adsorbed on the coronene molecule

    The Volunteer Satisfaction Survey (VSS): adaptation and psychometric properties among Portuguese Volunteers

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    (1) Background: Volunteering satisfaction is one significant construct that nourishes the sustaining of volunteer work, and it is present in reference models such as the three-stage volunteer process model (VPM). The volunteer satisfaction survey (VSS), created by Vecina, Chacón and Sueiro, evaluates three different domains of volunteer satisfaction: specific motivations, organization management and volunteering tasks. The aim of this study was to adapt the instrument and explore the psychometric properties of the 17 items of the VSS in a sample of Portuguese volunteers. (2) Methods: The sample was composed of 335 Portuguese volunteers (aged between 14 and 81 years), mainly women (76.4%). Measures included volunteer satisfaction, work engagement and organizational commitment. (3) Results: The original three-factor model was tested with a confirmatory factor analysis (CFA) and the model fitted the data. Satisfactory levels of internal consistency, discriminant and convergent validity were found. (4) Conclusions: The VSS reveals good psychometric properties and can be considered a useful tool for professionals and future research for volunteers’ satisfaction assessment.info:eu-repo/semantics/publishedVersio
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