762 research outputs found

    Interoperability and Standards: The Way for Innovative Design in Networked Working Environments

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    Organised by: Cranfield UniversityIn today’s networked economy, strategic business partnerships and outsourcing has become the dominant paradigm where companies focus on core competencies and skills, as creative design, manufacturing, or selling. However, achieving seamless interoperability is an ongoing challenge these networks are facing, due to their distributed and heterogeneous nature. Part of the solution relies on adoption of standards for design and product data representation, but for sectors predominantly characterized by SMEs, such as the furniture sector, implementations need to be tailored to reduce costs. This paper recommends a set of best practices for the fast adoption of the ISO funStep standard modules and presents a framework that enables the usage of visualization data as a way to reduce costs in manufacturing and electronic catalogue design.Mori Seiki – The Machine Tool Compan

    Metal-insulator transition in Nd1x_{1-x}Eux_{x}NiO3_{3} compounds

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    Polycrystalline Nd1x_{1-x}Eux_{x}NiO3_3 (0x0.50 \leq x \leq 0.5) compounds were synthesized in order to investigate the character of the metal-insulator (MI) phase transition in this series. Samples were prepared through the sol-gel route and subjected to heat treatments at \sim1000 ^\circC under oxygen pressures as high as 80 bar. X-ray Diffraction (XRD) and Neutron Powder Diffraction (NPD), electrical resistivity ρ(T)\rho(T), and Magnetization M(T)M(T) measurements were performed on these compounds. The results of NPD and XRD indicated that the samples crystallize in an orthorhombic distorted perovskite structure, space group PbnmPbnm. The analysis of the structural parameters revealed a sudden and small expansion of \sim0.2% of the unit cell volume when electronic localization occurs. This expansion was attributed to a small increase of \sim0.003 \AA{} of the average Ni-O distance and a simultaneous decrease of \sim0.5- 0.5^\circ of the Ni-O-Ni superexchange angle. The ρ(T)\rho(T) measurements revealed a MI transition occurring at temperatures ranging from TMI193T_{\rm MI}\sim 193 to 336 K for samples with x=0x = 0 and 0.50, respectively. These measurements also show a large thermal hysteresis in NdNiO3_{3} during heating and cooling processes suggesting a first-order character of the phase transition at TMIT_{\rm MI}. The width of this thermal hysteresis was found to decrease appreciably for the sample Nd0.7_{0.7}Eu0.3_{0.3}NiO3_{3}. The results indicate that cation disorder associated with increasing substitution of Nd by Eu is responsible for changing the first order character of the transition in NdNiO3_{3}.Comment: 19 pages, 9 figure

    Mudanças ocorridas na composição florística em decorrência da exploração florestal em uma área de floresta de Terra firme na região de Paragominas, PA.

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    O objetivo da presente pesquisa foi avaliar as mudanças ocorridas na composição florística, considerando duas intensidades de colheita de madeira, em 108 ha de floresta, na Fazenda Rio Capim, pertencente à Cikel Brasil Verde Madeiras Ltda., município de Paragominas, Estado do Pará. Os dados foram coletados, em duas ocasiões (2003, antes da exploração e em 2004, após a exploração) em 36 parcelas permanentes quadradas de 0,25 ha, estabelecidas aleatoriamente na área, sendo doze para estudar a floresta não explorada, doze para a explorada com colheita apenas do fuste comercial das árvores e doze para a explorada com colheita do fuste e dos resíduos lenhosos. Todos os indivíduos com DAP > 10 cm foram registrados. Antes da exploração, ocorreram 4469 árvores nas 36 parcelas amostradas (nove hectares), distribuídos em 46 famílias, 138 gêneros e 228 espécies. Após a exploração, foram registrados 4330 indivíduos, porém duas espécies desapareceram (Licaria sp. e Nectandra sp.). A composição florística, nas duas intensidades de colheita, sofreu alterações significantes devido à exploração de impacto reduzido a que foi submetida. Entretanto, não houve alterações significantes entre as duas áreas, demonstrando que, em termos ecológicos, a retirada dos resíduos lenhosos após a colheita dos fustes não implicou em danos significativos à floresta remanescente. Após a exploração, a composição florística, mesmo com pequenas alterações, não mostrou significância entre as três comunidades, sugerindo que com a intensidade de exploração aplicada, mais a retirada adicional dos resíduos, a floresta deve manter suas características bem semelhantes à floresta original, apesar de menos rica no estoque adulto, em termos econômicos

    Efeito de duas intensidades de colheita de madeira na estrutura de uma floresta natural na região de Paragominas, Pará.

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    Foram estudadas as mudanças na estrutura de 108ha de uma floresta primária submetida a duas intensidades de colheita de madeira, na Fazenda Rio Capim, pertencente à Cikel Brasil Verde Madeiras Ltda., no município de Paragominas, Pará. Os dados foram coletados, em dois períodos (2003, antes da exploração, e 2004, após a exploração) em 36 parcelas permanentes quadradas de 0,25ha, estabelecidas aleatoriamente na área, sendo12 em floresta não-explorada: Testemunha - T0; 12 em floresta explorada com colheita apenas do fuste comercial das árvores: Tratamento - T1; e 12 em floresta explorada com colheita do fuste e dos resíduos lenhosos: Tratamento - T2. Em 2003 foram registrados 4469 indivíduos com DAP > 10cm, nas 36 parcelas amostradas (9ha). Sete meses após a exploração (2004), foram observados na área 4531 indivíduos com DAP > 10cm, sendo 4330 vivos. Lecythis idatimon, Poecilanthe effusa, Rinorea flavescens, Eschweilera grandiflora, Eschweilera pedicellata, Inga sp., Protium spp., Vouacapoua americana, Guatteria poeppigiana e Eschweilera coriacea foram as dez espécies mais importantes, tanto antes como após a exploração. A estrutura da floresta, tanto no T1 como no T2, sofreu alterações significantes devido à exploração a que foi submetida. Entretanto, não foram verificadas diferenças significativas entre os três tratamentos, sugerindo que com a intensidade de exploração aplicada, mais a retirada adicional dos resíduos, a floresta manteve as características semelhantes à floresta original, apesar do menor estoque de árvores adultas de espécies comerciais. Recomendam-se estudos sobre a regeneração natural (DAP < 10cm), silvicultura pós-colheita e crescimento da floresta

    Disruption of MicroRNA Expression in Human Airway Cells by Diesel Exhaust Particles Is Linked to Tumorigenesis-Associated Pathways

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    BackgroundParticulate matter (PM) is associated with adverse airway health effects; however, the underlying mechanism in disease initiation is still largely unknown. Recently, microRNAs (miRNAs; small noncoding RNAs) have been suggested to be important in maintaining the lung in a disease-free state through regulation of gene expression. Although many studies have shown aberrant miRNA expression patterns in diseased versus healthy tissue, little is known regarding whether environmental agents can induce such changes.ObjectivesWe used diesel exhaust particles (DEP), the largest source of emitted airborne PM, to investigate pollutant-induced changes in miRNA expression in airway epithelial cells. We hypothesized that DEP exposure can lead to disruption of normal miRNA expression patterns, representing a plausible novel mechanism through which DEP can mediate disease initiation.MethodsHuman bronchial epithelial cells were grown at air–liquid interface until they reached mucociliary differentiation. After treating the cells with 10 μg/cm2 DEP for 24 hr, we analyzed total RNA for miRNA expression using microarray profile analysis and quantitative real-time polymerase chain reaction.ResultsDEP exposure changed the miRNA expression profile in human airway epithelial cells. Specifically, 197 of 313 detectable miRNAs (62.9%) were either up-regulated or down-regulated by 1.5-fold. Molecular network analysis of putative targets of the 12 most altered miRNAs indicated that DEP exposure is associated with inflammatory responses pathways and a strong tumorigenic disease signature.ConclusionsAlteration of miRNA expression profiles by environmental pollutants such as DEP can modify cellular processes by regulation of gene expression, which may lead to disease pathogenesis

    Heterotic Compactification, An Algorithmic Approach

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    We approach string phenomenology from the perspective of computational algebraic geometry, by providing new and efficient techniques for proving stability and calculating particle spectra in heterotic compactifications. This is done in the context of complete intersection Calabi-Yau manifolds in a single projective space where we classify positive monad bundles. Using a combination of analytic methods and computer algebra we prove stability for all such bundles and compute the complete particle spectrum, including gauge singlets. In particular, we find that the number of anti-generations vanishes for all our bundles and that the spectrum is manifestly moduli-dependent.Comment: 36 pages, Late

    The upper critical field in superconducting MgB_2

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    The upper critical field Hc2(T) of sintered pellets of the recently discovered MgB_2 superconductor was investigated in magnetic fields up to 16 T. The upper critical field of the major fraction of the investigated sample was determined from ac susceptibility and resistance data and was found to increase up to Hc2(0) = 13 T at T = 0 corresponding to a coherence length of 5.0 nm. A small fraction of the sample exhibits higher upper critical fields which were measured both resistively and by dc magnetization measurements. The temperature dependence of the upper critical field, Hc2(T), shows a positive curvature near Tc and at intermediate temperatures. This positive curvature of Hc2(T) is similar to that found for the borocarbides YNi_2B_2C and LuNi_2B_2C indicating that MgB_2 is in the clean limit.Comment: 8 pages with 4 figure
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