988 resultados para Science - Experiments
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Results of experiments recently performed are reported, in which two optical parametric amplifiers were set up to generate two independently quadrature squeezed continuous wave laser beams. The transformation of quadrature squeezed states into polarization squeezed states and into states with spatial quantum correlations is demonstrated. By utilizing two squeezed laser beams, a polarization squeezed state exhibiting three simultaneously squeezed Stokes operator variances was generated. Continuous variable polarization entanglement was generated and the Einstein-Podolsky-Rosen paradox was observed. A pair of Stokes operators satisfied both the inseparability criterion and the conditional variance criterion. Values of 0.49 and 0.77, respectively, were observed, with entanglement requiring values below unity. The inseparability measure of the observed quadrature entanglement was 0.44. This value is sufficient for a demonstration of quantum teleportation, which is the next experimental goal of the authors.
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Functional knowledge of the physiological basis of crop adaptation to stress is a prerequisite for exploiting specific adaptation to stress environments in breeding programs. This paper presents an analysis of yield components for pearl millet, to explain the specific adaptation of local landraces to stress environments in Rajasthan, India. Six genotypes, ranging from high-tillering traditional landraces to low-tillering open-pollinated modern cultivars, were grown in 20 experiments, covering a range of nonstress and drought stress patterns. In each experiment, yield components (particle number, grain number, 100 grain mass) were measured separately for main shoots, basal tillers, and nodal tillers. Under optimum conditions, landraces had a significantly lower grain yield than the cultivars, but no significant differences were observed at yield levels around 1 ton ha(-1). This genotype x environment interaction for grain yield was due to a difference in yield strategy, where landraces aimed at minimising the risk of a crop failure under stress conditions, and modem cultivars aimed at maximising yield potential under optimum conditions. A key aspect of the adaptation of landraces was the small size of the main shoot panicle, as it minimised (1) the loss of productive tillers during stem elongation; (2) the delay in anthesis if mid-season drought occurs; and (3) the reduction in panicle productivity of the basal tillers under stress. In addition, a low investment in structural panicle weight, relative to vegetative crop growth rate, promoted the production of nodal tillers, providing a mechanism to compensate for reduced basal tiller productivity if stress occurred around anthesis. A low maximum 100 grain mass also ensured individual grain mass was little affected by environmental conditions. The strategy of the high-tillering landraces carries a yield penalty under optimum conditions, but is expected to minimise the risk of a crop failure, particularly if mid-season drought stress occurs. The yield architecture of low-tillering varieties, by contrast, will be suited to end-of-season drought stress, provided anthesis is early. Application of the above adaptation mechanisms into a breeding program could enable the identification of plant types that match the prevalent stress patterns in the target environments. (C) 2003 E.J. van Oosterom. Published by Elsevier Science B.V. All rights reserved.
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Esta dissertação trata da análise da produção científica e tecnológica internacional e brasileira na área de conhecimento Engenharia Civil, por meio de indicadores bibliométricos. A área Engenharia Civil foi escolhida em razão da sua relevância para o desenvolvimento econômico do país. No entanto, em termos absolutos e relativos, está entre os setores tecnologicamente mais atrasados da economia. A bibliometria é uma disciplina com alcance multidisciplinar que estuda o uso e os aspectos quantitativos da produção científica registrada. Os indicadores de produção científica são objeto de análise de várias áreas do conhecimento, tanto para o planejamento e a execução de políticas públicas de vários setores quanto para maior conhecimento da comunidade científica sobre o sistema em que está inserida. A metodologia utilizada para a elaboração deste estudo descritivo de caráter exploratório foi a análise documental e bibliométrica, baseada em dados das publicações científicas, no período de 1970 a 2012, e tecnológicas, no período de 2001 a 2012, da área Engenharia Civil, indexadas nas bases de dados Science Citattion Index Expanded (SCI); Social Science Citation Index (SSCI); Conference Proceedings Citation Index (CPCI) e da Derwent Innovations Index (DII), que compõem a base de dados multidisciplinar da Web of Sicence (WoS). As informações foram qualificadas e quantificadas com o auxílio do software bibliométrico VantagePoint®. Os resultados obtidos confirmaram o baixo número de publicações científicas e tecnológicas na área de conhecimento Engenharia Civil de autores filiados a instituições de ensino e pesquisa brasileiras quando comparados aos dos países industrializados. Existe um conjunto de fortes condicionantes que ultrapassam o poder de decisão e de influência da academia, dificultando e limitando a disseminação das pesquisas e patentes brasileiras relacionadas a fatores de caráter sistêmico e cultural. A possibilidade de análise de indicadores de produção científica e tecnológica na Engenharia Civil contribui para criar políticas que, se utilizadas por agências de fomento, podem subsidiar investimentos mais fundamentados por parte dos governos e da iniciativa privada, a exemplo do que é feito por outros setores industriais.
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This study is focused on the establishment of relationships between the injection moulding processing conditions, the applied thermomechanical environment (TME) and the tensile properties of talc-filled polypropylene,adopting a new extended concept of thermomechanical indices (TMI). In this approach, TMI are calculated from computational simulations of the moulding process that characterise the TME during processing, which are then related to the mechanical properties of the mouldings. In this study, this concept is extended to both the filling and the packing phases, with new TMI defined related to the morphology developed during these phases. A design of experiments approach based on Taguchi orthogonal arrays was adopted to vary the injection moulding parameters (injection flow rate, injection temperature, mould wall temperature and holding pressure), and thus, the TME. Results from analysis of variance for injection-moulded tensile specimens have shown that among the considered processing conditions, the flow rate is the most significant parameter for the Young’s modulus; the flow rate and melt temperature are the most significant for the strain at break; and the holding pressure and flow rate are the most significant for the stress at yield. The yield stress and Young’s modulus were found to be governed mostly by the thermostress index (TSI, related to the orientation of the skin layer), whilst the strain at break depends on both the TSI and the cooling index (CI, associated to the crystallinity degree of the core region). The proposed TMI approach provides predictive capabilities of the mechanical response of injection-moulded components, which is a valuable input during their design stage.
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This work focused on the study of the impact event on molded parts in the framework of automotive components. The influence of the impact conditions and processing parameters on the mechanical behavior of talc-filled polypropylene specimens was analyzed. The specimens were lateral-gate discs produced by injection molding, and the mechanical characterization was performed through instrumented falling weight impact tests concomitantly assisted with high-speed videography. Results analyzed using the analysis of variance (ANOVA) method have shown that from the considered parameters, only the dart diameter and test temperature have significant influence on the falling weight impact properties. Higher dart diameter leads to higher peak force and peak energy results. Conversely, higher levels of test temperatures lead to lower values of peak force and peak energy. By means of high-speed videography, a more brittle fracture was observed for experiments with higher levels of test velocity and dart diameter and lower levels of test temperature. The injection-molding process conditions assessed in this study have an influence on the impact response of moldings, mainly on the deformation capabilities of the moldings.
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Abstract: If we think there is a significant number of legal offshore in the globalized world, then there is not even a global consensus about what «corruption» is. The «illegal corruption» in a country may be legal in another. Moreover, the great global corruption is above the law or above democratic States. And not all democratic States are «Rule of Law». Therefore, the solution is global earlier in time and space law, democratic, free and true law. While the human being does not reach a consensus of what «corruption» really is, the discussion will not go further than a caricature. One of the other problems about «corruption» is that it is very difficult to establish the imputation of crimes, including «corruption» (v.g. Portugal) on some «companies», corporations. We have a juridical problem in the composition of the art. 11. of the Portuguese Penal Code.
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Thermal degradation of as electrospun chitosan membranes and samples subsequently treated with ethanol and cross-linked with glutaraldehyde (GA) have been studied by thermogravimetry (TG) coupled with an infrared spectrometer (FTIR). The influence of the electrospinning process and cross-linking in the electrospun chitosan thermal stability was evaluated. Up to three degradation steps were observed in the TG data, corresponding to water dehydration reaction at temperatures below 100 ºC, loss of side groups formed between the amine groups of chitosan and trifluoroacetic acid between 150 – 270 ºC and chitosan thermal degradation that starts around 250 ºC and goes up to 400 ºC. The Kissinger model was employed to evaluate the activation energies of the electrospun membranes during isothermal experiments and revealed that thermal degradation activation energy increases for the samples processed by electrospinning and subsequent neutralization and cross-linking treatments with respect to the neat chitosan powder.
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ABSTRACT The sunflower plant is an oilseed crop that has aroused a great interest in the Brazilian and international scenery especillay because of the possibility of using its oil for biodiesel production. The objective of this study was to evaluate productivity and yield components of Embrapa 122 sunflower according to the spatial arrangement. Treatments were arranged in 4 x 4 factorial arrangement, which are the four spacings between rows (0.30; 0.50; 0.70 and 0.90 m) and four sowing densities (30,000; 45,000; 60,000 and 75,000 plants ha-1). The experiment was carried out in a complete randomized block design with four replications. The experiments were conducted in the experimental area of the Plant Science Department in Fortaleza, State of Ceará-Brazil and on the Curu Vale Experimental Farm in Pentecoste, State of Ceará-Brazil. Productivity and the following production components were analyzed in the end of the crop cycle: harvested capitula, capitulum diameter, capitulum mass, achene mass per capitulum, mass of 100 achenes, achenes per capitulum, harvest index and oil content in the achenes. The experiments were analyzed jointly in relation to the cropping area and the data submitted to analysis of variance and quantitative factors tested by polynomial regression. The variables, spacing, density and cropping area did not interact with these variables and the spatial arrangement of the plants affected only the components. The cropping area influences the productive behavior of sunflower Embrapa 122. The spatial arrangement of the plants of sunflower of variety Embrapa 122 influences yield components but does not affect productivity.
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Revista Lusófona de Línguas, Culturas e Tradução
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Com a criação da teoria das redes, assistiu-se nos últimos anos a uma revolução científica de carácter interdisciplinar Não é uma teoria inteiramente nova, tendo sido precedida pela criação por P. Erdvos, nos anos sessenta, da teoria dos grafos aleatórios. Esta última é uma teoria puramente matemática, donde termos escrito “grafo” em lugar de “rede”. Apenas recentemente podemos falar de uma efectiva teoria das redes reais, e isso devido ao abandono de algumas das ideias essenciais avançadas por Erdvos, em especial a ideia de partir de um conjunto previamente dado de nós, os quais de seguida vão sendo conectados aleatoriamente com probabilidade p. Este quadro geral começou a ser modificado pelo chamado modelo dos “mundo-pequenos” proposto em 1998 por Duncan Watts e Steve Strogatz, modificação que se tornou ainda mais radical quando, em 1999, Albert Barabási e colaboradores propuseram um modelo no qual os nós vão progressivamente nascendo e conectados por uma função de preferência: um nó conecta-se em proporção às ligações que os outros nós já possuem, pelo que quantas mais ligações um nó possui maior a probabilidade de receber ulteriores ligações.
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First-generation progeny of field-collected Psorophora ferox, Aedes scapularis, and Aedes serratus from the Rocio encephalitis epidemic zone in S.Paulo State, Brazil, were tested for vector competency in the laboratory. Psorophora ferox and Ae. scapularis are susceptible to per os infection with Rocio virus and can transmit the virus by bite following a suitable incubation period. Oral ID50S for the two species (10(4.1) and 10(4.3) Vero cell plaque forming units, respectively) did not differ significantly. Infection rates in Ae. serratus never exceeded 36%, and, consequently, an ID50 could not be calculated for this species. It is unlikely that Ae. serratus is an epidemiologically important vector of Rocio virus. The utility of an in vitro feeding technique for demonstrating virus transmission by infected mosquitoes and difficulties encountered in working with uncolonized progeny of field-collected mosquitoes are discussed.
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The mycelium and young fruiting bodies of Agaricus blazei were submitted to supercritical CO2 extraction, in a modified commercial flow apparatus, at temperatures from 40 to 80 ºC, pressures up to 600 bar and CO2 flow-rates from 2.0 to 9.0 g.min-1. The best extraction conditions of secondary metabolites, whereby the degree of solubilization (g extract/100 g of fungi) is the highest, was obtained with pure CO2 at 400 bar, 70 ºC and a CO2 flow rate of 5.7g.min-1. The extract in that conditions were analysed by GC-Ms. In order to increase the extraction yield of secondary metabolites, which are mostly present in glycolipid fractions, a polar compound (ethanol) was used as co-solvent in the proportions of 5 and 10 % (mol/mol). The presence of ethanol increased the yield when compared with the extraction with pure CO2. Moreover, a simple model was applied to the supercritical CO2 extraction of secondary metabolites from Agaricus blazei.
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Three different methods were used to introduce 1.0 wt.% of Pt in bifunctional Pt/MCM-22 zeolite catalysts: ion exchange with Pt(NH3)(4)(2+), incipient wetness impregnation with PtCl6H2 and mechanical mixture with Pt/Al2O3. The Pt dispersion was estimated by transmission electron microscopy and the hydrogenating activity with toluene hydrogenation at 110 degrees C. From these experiments, it can be concluded that with the ion exchanged sample, platinum was located within the inner micropores and on the outer surface, whereas with the impregnated one, platinum was essentially on the outer surface under the form of large particles. With all the samples there is a fast initial decrease in the activity for n-hexane hydroisomerisation at 250 degrees C. With exchanged and impregnated samples, this decrease is followed by a plateau, the activity value being then higher with impregnated sample. For the sample prepared by mechanical mixture a continuous decrease in activity can be observed. All these differences can be related with the distinct locations of Pt.
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We present a novel data analysis strategy which combined with subcellular fractionation and liquid chromatography-mass spectrometry (LC-MS) based proteomics provides a simple and effective workflow for global drug profiling. Five subcellular fractions were obtained by differential centrifugation followed by high resolution LC-MS and complete functional regulation analysis. The methodology combines functional regulation and enrichment analysis into a single visual summary. The workflow enables improved insight into perturbations caused by drugs. We provide a statistical argument to demonstrate that even crude subcellular fractions leads to improved functional characterization. We demonstrate this data analysis strategy on data obtained in a MS-based global drug profiling study. However, this strategy can also be performed on other types of large scale biological data.