439 research outputs found

    All that glitters is not gold: polarization amid poverty reduction in Ghana

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    Ghana is an exceptional case in the Sub-Saharan Africa (SSA) landscape. Together with a handful of other countries, Ghana offers the opportunity to analyze the distributional changes in the past two decades, since four comparable household surveys are available. In addition, unlike many other countries in SSA, Ghana's rapid growth translated into fast poverty reduction. A closer look at the distributional changes that occurred in the same period, however, suggests less optimism. The present paper develops an innovative methodology to analyze the distributional changes that occurred and their drivers, with a high degree of accuracy and granularity. Looking at the results from 1991 to 2012, the paper documents how the distributional changes over time hollowed out the middle of the Ghanaian household consumption distribution and increased the concentration of households around the highest and lowest deciles; there was a clear surge in polarization indeed. When looking at the drivers of polarization, household characteristics, educational attainment, and access to basic infrastructure all tended to increase over time the size of the upper and lower tails of the consumption distribution and, as a consequence, the degree of polarization

    A Test of Gravitational Theories Including Torsion with the BepiColombo Radio Science Experiment

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    Within the framework of the relativity experiment of the ESA/JAXA BepiColombo mission to Mercury, which was launched at the end of 2018, we describe how a test of alternative theories of gravity, including torsion can be set up. Following March et al. (2011), the effects of a non-vanishing spacetime torsion have been parameterized by three torsion parameters, t(1), t(2), and t(3). These parameters can be estimated within a global least squares fit, together with a number of parameters of interest, such as post-Newtonian parameters gamma and beta, and the orbits of Mercury and the Earth. The simulations have been performed by means of the ORBIT14 orbit determination software, which was developed by the Celestial Mechanics Group of the University of Pisa for the analysis of the BepiColombo radio science experiment. We claim that the torsion parameters can be determined by means of the relativity experiment of BepiColombo at the level of some parts in 10(-4), which is a significant result for constraining gravitational theories that allow spacetime torsion

    Dynamic reconfiguration of electrical connections for partially shaded PV modules: Technical and economical performances of an Arduino-based prototype

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    The partial shading phenomenon is a well known problem of photovoltaic plants. Partial shading leads to undesirable effects such the electrical mismatch, the generation of hot spots, and generally the decrease of production of electric energy. To mitigate the last effect, a dynamic reconfiguration of the electrical connections between modules was taken into account. In this paper, starting from an already developed system for a small-scale photovoltaic plant reconfiguration, the study of the economical benefits of the employment of a reconfigurator are traced. Five different incentive policies of diverse Countries have been considered to evaluate the increase of Net Present Value of system with and without a reconfigurator

    Experimental study on B-spline-based modulation schemes applied in multilevel inverters for electric drive applications

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    This work presents the design, simulation, and experimental validation of new B-Spline-based modulation techniques applied to a Multilevel Power Inverter (MPI), particularly focusing the attention on the harmonic content of the output voltages of the inverter. Simulation and experimental results are proposed and discussed, mainly describing the potential benefits, such as the increase of the multi-level operation of the converter, and drawbacks (low-order harmonics) related to the adoption of B-Spline functions for multilevel inverters applied in the field of electrical drives

    Oxidative status imbalance in patients with metabolic syndrome: Role of the myeloperoxidase/hydrogen peroxide axis

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    The present study evaluated the cardiometabolic and redox balance profiles in patients with Metabolic Syndrome compared to apparently healthy individuals, and the participation of the myeloperoxidase/hydrogen peroxide axis in systemic lipid peroxidation. Twenty-four patients with Metabolic Syndrome and eighteen controls underwent a full clinical assessment. Venous blood samples were collected for general biochemical dosages, as well as for the oxidative stress analyses (superoxide dismutase, catalase, and arginase activities; and lipid peroxidation, myeloperoxidase activity, nitrite, and hydrogen peroxide concentrations in plasma). Arterial stiffness was assessed by radial artery applanation tonometry. Plasma lipid peroxidation, erythrocyte superoxide dismutase activity, myeloperoxidase activity, and hydrogen peroxide concentrations were shown to be increased in Metabolic Syndrome patients, without significant differences for the other enzymes, plasma nitrite concentrations, and arterial stiffness. Linear regression analysis revealed a positive and significant correlation between lipid peroxidation and myeloperoxidase and also between this enzyme and hydrogen peroxide. In contrast, such correlation was not observed between lipid peroxidation and hydrogen peroxide. In summary, Metabolic Syndrome patients exhibited evident systemic redox imbalance compared to controls, with the possible participation of the myeloperoxidase/hydrogen peroxide axis as a contributor in lipid peroxidation

    Challenges for the Goal of 100% Renewable Energy Sources to Fit the Green Transition

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    The increasing penetration of Renewable Energy (RE) into the electrical market is desirable in terms of sustainability. Nevertheless, it is a challenge that all the interested actors shall address from both the technical and economical points of view. This paper provides an overview of the main challenges and solutions towards the technological transition to an electrical system with 100% renewable energy sources in terms of innovations and operative limits of the traditional systems. These innovative paradigms will also address the social impact and government policies

    Avaliação do desempenho relativo de bancos de dados NoSQL para arquivos de genótipos.

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    A bioinformática e a genômica trabalham com bases de dados fora do padrão tradicional ou clássico que, por sua vez, caracterizam-se pela organizacão tabular e pelo tratamento destas em SGBDRs. Arquivos de genótipos são exemplos de bases de dados não clássicas e são caracterizados por serem gerados como arquivos textos, com dados desbalanceados, com alta dimensionalidade e por ocuparem muito espaço, entre outros aspectos. Os SGBDRs não têm se mostrado uma boa solucão para o tratamento de tais bases e, portanto, o presente trabalho busca avaliar o desempenho relativo entre bancos de dados NoSQL que representam duas famílias de diferentes modelo de dados, a partir de cenários de teste para a manipulação de arquivos de genótipo
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