1,959 research outputs found

    Factores climáticos no consumo de energia eléctrica: um caso com utilização de data mining.

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    4ª Conferência Ibérica de Sistemas e Tecnologias de Informação, 17 a 20 de Junho de 2009, Póvoa de Varzim.Este trabalho tem por objectivo identificar causas responsáveis por variações no consumo horário de energia com base na identificação de padrões e relações entre os dados de consumo e várias variáveis climatéricas. Para tal utilizam-se técnicas de data mining, nomeadamente a metodologia CRISP-DM e software de data warehouse MS SQL Server. Assim, foi possível verificar que as variáveis climatológicas têm influência muito significativa na produção de energia eléctrica, tendo sido possível prever os consumos de 2007 com um erro absoluto médio de 1,4 MW. Identificam-se ainda vários padrões no comportamento do consumo ou produção de energia eléctrica, nem todos espectáveis face ao conhecimento actual de domínio

    O efeito de factores climáticos no consumo de energia eléctrica

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    Neste trabalho identificam-se as causas responsáveis por variações no consumo horário de energia com base na identificação de padrões e relações entre os dados de consumo e várias variáveis climatéricas. Para tal utilizam-se técnicas de data mining, nomeadamente a metodologia CRISP-DM e software de data warehouse MS SQL Server. Assim, foi possível verificar que as variáveis climatéricas têm influência muito significativa na produção de energia eléctrica, tendo sido possível prever os consumos de 2007 com um erro absoluto médio de 1,4 MW. Identificam-se ainda vários padrões no comportamento do consumo ou produção de energia eléctrica, nem todos espectáveis face ao conhecimento actual de domínio.info:eu-repo/semantics/publishedVersio

    Alignment tests for low CMB multipoles

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    We investigate the large scale anomalies in the angular distribution of the cosmic microwave background radiation as measured by WMAP using several tests. These tests, based on the multipole vector expansion, measure correlations between the phases of the multipoles as expressed by the directions of the multipole vectors and their associated normal planes. We have computed the probability distribution functions for 46 such tests, for the multipoles l=2-5. We confirm earlier findings that point to a high level of alignment between l=2 (quadrupole) and l=3 (octopole), but with our tests we do not find significant planarity in the octopole. In addition, we have found other possible anomalies in the alignment between the octopole and the l=4 (hexadecupole) components, as well as in the planarity of l=4 and l=5. We introduce the notion of a total likelihood to estimate the relevance of the low-multipoles tests of non-gaussianity. We show that, as a result of these tests, the CMB maps which are most widely used for cosmological analysis lie within the ~ 10% of randomly generated maps with lowest likelihoods.Comment: References added, updated discussion on alignment with Ecliptic Plane. 12 Pages, 6 Figures. Results for additional maps, the normalized frequencies for the tests and a Mathematica Notebook that computes the tests can be found on http://fma.if.usp.br/~abramo/MVA.htm

    Major anthocyanins in elderberry effectively trap methylglyoxal and reduce cytotoxicity of methylglyoxal in HepG2 cell line

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    The accumulation of advanced glycation end-products (AGEs) in the body is implicated in numerous diseases, being methylglyoxal (MGO) one of the main precursors. One of the strategies to reduce AGEs accumulation might be acting in an early stage of glycation by trapping MGO. Thus, this work aimed to evaluate, for the first time, the potential of elderberries polyphenols to trap MGO, access the formation of MGO adducts, and evaluate the cytoprotection effect in HepG2 and Caco-2 cells. The results demonstrated that monoglycosylated anthocyanins (cyanidin-3-glucoside and cyanidin-3-sambubioside) are very efficient in trapping MGO, forming mono- and di-adducts. Quercetin-3-glucoside and quercetin-3-rutinoside reacted slowly, while diglycosylated anthocyanins did not react. The trapping of MGO by elderberry monoglycosylated anthocyanins significantly decreased the MGO cytotoxicity in HepG2 cells (∼70 % of cell viability), while the effect in Caco-2 cells was lower (∼50 %). Thus, elderberry phenolics present antiglycation potential by trapping MGOpublishe

    Gamma irradiation preservation of chestnut fruits: effects on color and texture

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    Chestnuts are a seasonal fruit that must be postharvest treated to meet food safety regulations. In this study the effect of gamma irradiation on color and texture of chestnut fruits from a European variety (Castanea sativa Miller) was reported. The fruits were subjected to gamma irradiation doses of 0.5, 3 and 6 kGy, with color and texture properties analyzed along a typical commercial period for this fruit after postharvest treatment, at 0, 15 and 30 days of storage. For L and b color parameters, significant differences (p < 0.05) were observed with irradiation dose (ID) only for higher doses of 3 kGy and 6 kGy. Along storage time (ST) significant differences (p < 0.05) were observed for fruits interior (half-cutted) after 15 days of storage. Regarding texture, differences on fruits were only detected for chestnuts irradiated with 6 kGy. With this study we can identify the maximum acceptable dose for irradiation processing of these fruits, concluding that gamma irradiation could be a promising alternative technology for postharvest disinfestation of European chestnuts varieties, to meet food safety international trade regulations, not affecting significantly two important parameters for the consumer, the color and texture

    Structural features and pro-inflammatory effects of water-soluble organic matter in inhalable fine urban air particles

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    The impact of inhalable fine particulate matter (PM2.5, aerodynamic diameter < 2.5 µm) on public health is of great concern worldwide. Knowledge on their harmful effects are mainly due to studies carried out with whole air particles, being the contribution of their different fractions largely unknown. Herein, a set of urban PM2.5 samples were collected during day and nighttime periods in Autumn and Spring, aiming to address the seasonal and day-night variability of water-soluble organic matter (WSOM) composition. In vitro analysis of oxidative and pro-inflammatory potential of WSOM samples was carried out in both acute (24 h) and chronic (3 weeks) exposure setups using Raw264.7 macrophages as cell model. Findings revealed that the structural composition of WSOM samples differs between seasons and in a day-night cycle. Cells exposure resulted in an increase in the transcription of the cytoprotective Hmox1 and pro-inflammatory genes Il1b and Nos2, leading to a moderate pro-inflammatory status. These macrophages showed an impaired capacity to subsequently respond to a strong pro-inflammatory stimulus such as bacterial lipopolysaccharide, which may implicate a compromised capacity to manage harmful pathogens. Further investigation on aerosol WSOM could help to constrain the mechanisms of WSOM-induced respiratory diseases and contribute to PM2.5 regulations.publishe

    Surface tension implementation for Gensmac 2D

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    In the present work we describe a method which allows the incorporation of surface tension into the GENSMAC2D code. This is achieved on two scales. First on the scale of a cell, the surface tension effects are incorporated into the free surface boundary conditions through the computation of the capillary pressure. The required curvature is estimated by fitting a least square circle to the free surface using the tracking particles in the cell and in its close neighbors. On a sub-cell scale, short wavelength perturbations are filtered out using a local 4-point stencil which is mass conservative. An efficient implementation is obtained through a dual representation of the cell data, using both a matrix representation, for ease at identifying neighbouring cells, and also a tree data structure, which permits the representation of specific groups of cells with additional information pertaining to that group. The resulting code is shown to be robust, and to produce accurate results when compared with exact solutions of selected fluid dynamic problems involving surface tension

    Real-Time Demonstration of Low-Complexity Time-Domain Chromatic Dispersion Equalization

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    We demonstrate real-time CD equalization (CDE) for coherent optical transmission systems using a low complexity time-domain (TD) multiplierless finite-impulse response (FIR)-based equalizer, based on a field-programmable gate array (FPGA) implementation. The real-time operation is performed for a single-channel 2.5 Gb/s QPSK optical signal with a performance penalty of only 0.15 dB with respect to the maximum performance. The hardware complexity is also evaluated in terms of occupation in a Virtex-6 FPGA-XC6VLX240T, revealing the high efficiency of the proposed CDE algorithm
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