178 research outputs found

    Revista de Indias y Anuario de Estudios Americanos. Visibilidad y uso de la edición electrónica

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    Una década americanista en línea, 2010, [En línea], Puesto en línea el 25 mayo 2010[EN] In this article we analyze the online visibility and content usage of two Americanist Journals published by CSIC, Revista de Indias and Anuario de Estudios Americanos. The online edition dates back to 2007; contents are comparable in terms of accessible documents, and both Journals are published in Open Access, with a 6-months embargo. We also discuss some methodological issues in terms of the need of a data normalization allowing the measurement of genuine downloads assimilable to document reading. Both Journals registered close to 500,000 normalized downloads along 2008 and 2009, most coming from Latin America and the United States (70%). Data show a high degree of repeated downloads of the same document from the same user (25% of total downloads) and indexation downloads (25% of normalized downloads), and also the lack of correlation between Journal’s visibility (webpage visits) and content usage (document downloads). Access restriction has a negative effect, as evidenced by the low downloading of embargoed documents[ES] En este artículo analizamos los datos de visibilidad y uso de las dos revistas de temática americanista editadas por el CSIC, Revista de Indias y Anuario de Estudios Americanos. La edición electrónica de ambas data de 2007, y su contenido en artículos accesibles es comparable; ambas se publican en Acceso Abierto (OA) con un embargo de acceso de 6 meses. También analizamos cuestiones metodológicas relativas al análisis de descargas, en el sentido de la necesidad de una normalización de los datos que permita determinar las descargas reales, asimilables a una lectura del documento. Durante los años 2008 y 2009, ambas revistas han recibido cerca de 500.000 descargas normalizadas, que provienen en su mayoría de Latinoamérica y Estados Unidos (70%). Los datos muestran el elevado número de descargas repetidas de documentos en periodos cortos de tiempo por el mismo usuario (25% de las totales registradas) y de descargas de indización (25% de las descargas normalizadas), y también la falta de correlación entre visibilidad de las revistas (visitas a páginas web) y uso de los contenidos (descarga de documentos). La restricción de acceso tiene un efecto perjudicial, evidenciado por el bajo nivel de descarga de los documentos sometidos a embargoPeer reviewe

    Beam self-cleaning in multimode optical fibers and hydrodynamic 2D turbulence

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    We experimentally demonstrate the conservation of the average mode number in the process of Kerr beam self-cleaning in a graded-index multimode optical fiber, in analogy with wave condensation in hydrodynamic 2D turbulence

    Radial basis approximation of single-phase flow in porous media based on the Green’s functions

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    The article discusses the problem of approximating solutions of differential equations describing the process of a two-dimensional fluid flow in porous media. The approximation is presented as a combination of radial basis functions on the basis of the Green’s function is used to solve the Poisson equation with variable coefficients in the case of steady state filtration and parabolic equations in the transient regime. To illustrate the effectiveness of the proposed approximation obtained by the field pressure distribution in the reservoir with a network of injection and production wells. Compare approximated pressure and design points to a satisfactory accuracy of the results

    Building surrogate models for two-phase flow of fluids in porous media based on spatial radial basis approximation

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    The paper proposes a method for constructing the surrogate models for two-phase flow based on a combination of finite-difference solutions and fine-grid spatial approximation. The method provides the approximate models for solving optimal control the operating parameters of field development

    Random mode coupling assists Kerr beam self-cleaning in a graded-index multimode optical fiber

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    In this paper, we numerically investigate the process of beam self-cleaning in a graded-index multimode optical fiber, by using the coupled-mode model. We introduce various models of random linear coupling between spatial modes, including coupling between all modes, or only between degenerate ones, and investigate the effects of random mode coupling on the beam self-cleaning process. The results of numerical investigations are in complete agreement with our experimental data

    Vitamin D supplementation and breast cancer prevention : a systematic review and meta-analysis of randomized clinical trials

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    In recent years, the scientific evidence linking vitamin D status or supplementation to breast cancer has grown notably. To investigate the role of vitamin D supplementation on breast cancer incidence, we conducted a systematic review and meta-analysis of randomized controlled trials comparing vitamin D with placebo or no treatment. We used OVID to search MEDLINE (R), EMBASE and CENTRAL until April 2012. We screened the reference lists of included studies and used the “Related Article” feature in PubMed to identify additional articles. No language restrictions were applied. Two reviewers independently extracted data on methodological quality, participants, intervention, comparison and outcomes. Risk Ratios and 95% Confident Intervals for breast cancer were pooled using a random-effects model. Heterogeneity was assessed using the I2 test. In sensitivity analysis, we assessed the impact of vitamin D dosage and mode of administration on treatment effects. Only two randomized controlled trials fulfilled the pre-set inclusion criteria. The pooled analysis included 5372 postmenopausal women. Overall, Risk Ratios and 95% Confident Intervals were 1.11 and 0.74–1.68. We found no evidence of heterogeneity. Neither vitamin D dosage nor mode of administration significantly affected breast cancer risk. However, treatment efficacy was somewhat greater when vitamin D was administered at the highest dosage and in combination with calcium (Risk Ratio 0.58, 95% Confident Interval 0.23–1.47 and Risk Ratio 0.93, 95% Confident Interval 0.54–1.60, respectively). In conclusions, vitamin D use seems not to be associated with a reduced risk of breast cancer development in postmenopausal women. However, the available evidence is still limited and inadequate to draw firm conclusions. Study protocol code: FARM8L2B5L

    Use of Hissopus officinalis L. culture for phytomelioration of carbonate outcrops of anthropogenic origin the South of European Russia

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    Eurasian-African species of the Lamiaceae family - Hissopus officinalis (L.) gradually enters the culture of the South of European Russia. Field experiments were conducted including the study of H. officinalis value to phytomeliorate cretaceous exposures in comparison with standard Agropyron cristatum Gaertn. crops and natural succession on the chalk outcrop of anthropogenic origin in the Belgorod region in 2008-201

    Biological resources of natural forage grassland of the cretaceous south of the European Russia

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    The main objective of the made researches was assessment of territorial confinedness of economic and valuable plant species and also a status and productivity of a natural forage grassland within agrolandscapes of the cretaceous South of the European Russia (the territory of the Belgorod region). Biological and vegetable resources of the natural forage grasslands of the East part of the Belgorod region in a subband of the southern forest-steppe were studie
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