923 resultados para Pseudo Relevance
Resumo:
This paper presents the 2005 Miracle’s team approach to the Ad-Hoc Information Retrieval tasks. The goal for the experiments this year was twofold: to continue testing the effect of combination approaches on information retrieval tasks, and improving our basic processing and indexing tools, adapting them to new languages with strange encoding schemes. The starting point was a set of basic components: stemming, transforming, filtering, proper nouns extraction, paragraph extraction, and pseudo-relevance feedback. Some of these basic components were used in different combinations and order of application for document indexing and for query processing. Second-order combinations were also tested, by averaging or selective combination of the documents retrieved by different approaches for a particular query. In the multilingual track, we concentrated our work on the merging process of the results of monolingual runs to get the overall multilingual result, relying on available translations. In both cross-lingual tracks, we have used available translation resources, and in some cases we have used a combination approach.
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We show, through some examples, that chemical activation by alkaline hydroxides permits the preparation of activated carbons with tailored pore volume, pore size distribution, pore structure and surface chemistry, which are useful for their application as electrodes in supercapacitors. Examples are presented discussing the importance of each of these properties on the double layer capacitance, on the kinetics of the electric double-layer charge-discharge process and on the pseudo-capacitative contribution from the surface functional groups or the addition of a conducting polymer.
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Cyclic pseudo-galactooligosaccharides were synthesized by cyclooligomerisation of isomeric azido-alkyne derivatives of beta-D-galactopyranose under Cu(I)-catalysed azide-alkyne 1,3-dipolar cycloaddition reaction conditions. The principal products isolated were cyclic dimers and trimers, with lower amounts of cyclic tetramer and pentamer also evident in some cases. Molecular mechanics calculations suggest very compact but flexible structures for the cyclic trimers, with secondary OH groups exposed outside the macrocycle and available for enzymatic glycosylation. The cyclic dimers and trimers represent a new type of acceptor substrate for Trypanosoma cruzi trans-sialidase, giving rise to doubly and triply sialylated glycomacrocycles, respectively.
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The put-pose of this paper is to analyze relationship patterns between headquarters and subsidiaries of Brazilian Multinationals Enterprises (BrMNEs). The key construct for that investigation is Subsidiary Initiative, which comprises Subsidiary Entrepreneurial Orientation, Autonomy, Integration, Local Competitive Context and Business Network. A survey was carried out in a sample of 65 subsidiaries of 29 BrMNEs. The main outcome is that subsidiaries are highly integrated and receive Entrepreneurial Orientation from Headquarters (HQs), but Initiative is limited. Actually, the main determinants of subsidiary's initiatives are Local Context and Business Networking in the host country. This apparent paradox may be explained by what we call 'rebellious subsidiaries', which take initiatives based on their business environment and connections, regardless of their HQs' directions or delegation of autonomy.
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Resuspended soil and other airborne particles adhered to the leaf surface affect the chemical composition of the plant. A well-defined cleaning procedure is necessary to avoid this problem, providing a correct assessment of the inherent chemical composition of bromeliads. To evaluate the influence of a washing procedure, INAA was applied for determining chemical elements in the leaves of bromeliads from Vriesea carinata species, both non-washed and washed with Alconox, EDTA and bi-distilled water. Br, Ce, Hg, La, Sc, Se, Sm and Th showed higher mass fractions in non-washed leaves. The washing procedure removed the exogenous material without leaching chemical elements from inside the tissues.
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Ceriporiopsis subvermispora is a promising white-rot fungus for biopulping. However, the underlying biochemistry involved in lignin removal and insignificant cellulose degradation by this species is not completely understood. This paper addresses this topic focusing on the involvement of ethanol-soluble extractives and wood transformation products in the biodegradation process. Cultures containing ethanol-extracted or in natura wood chips presented similar levels of extracellular enzymes and degradation of wood components. Fe3+-reducing compounds present in undecayed Pinus taeda were rapidly diminished by fungal degradation. Lignin-degradation products released during biodegradation restored part of the Fe3+-reducing activity. However, Fe3+ reduction was ineffective in presence of 0.5 mM oxalate at pH 4.5. Fungal consumption of Fe3+-reducing compounds and secretion of oxalic acid minimized the significance of Fenton`s reaction in the initial stages of wood biotreatment. This would explain limited polysaccharide degradation by the fungus that also lacks a complete set of hydrolytic enzymes. Scientific relevance of the paper: Ceriporiopsis subvermispora is a white-rot fungus suitable for biopulping processes because it degrades lignin selectively and causes significant structural changes on the wood components during the earlier decay stages. However, the intricate mechanism to explain lignin transformation and insignificant cellulose degradation by this species remains poorly understood. Some recent evidences pointed out for lipid peroxidation reactions as all initiating process explaining lignin degradation. On the other hand, alkylitaconic acids produced by the fungus via transformations of fatty acids occurring in wood showed to prevent polysaccharide degradation in Fenton reactions. In this context, one may conclude that the involvement of native wood substances or their transformation products in the overall wood biodegradation process induced by C subvermispora is still a matter of discussion. While free and esterified fatty acids present in wood extractives may be involved in the biosynthesis of alkylitaconic acids and in lipid peroxidation reactions, some extractives and lignin degradation products can reduce Fe3+, providing Fe2+ species needed to form OH radical via Fenton`s reaction. The present study focuses on this topic by evaluating the relevance of ethanol-soluble extractives and wood transformation products on the biodegradation of P. taeda by C subvermispora. For this, solid-state cultures containing ethanol-extracted and in natura wood chips were evaluated in details for up to 4 weeks. (C) 2007 Elsevier Ltd. All rights reserved.
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The brown rot fungus Wolfiporia cocos and the selective white rot fungus Perenniporia medulla-panis produce peptides and phenolate-derivative compounds as low molecular weight Fe(3+)-reductants. Phenolates were the major compounds with Fe(3+)-reducing activity in both fungi and displayed Fe(3+)-reducing activity at pH 2.0 and 4.5 in the absence and presence of oxalic acid. The chemical structures of these compounds were identified. Together with Fe(3+) and H(2)O(2) (mediated Fenton reaction) they produced oxygen radicals that oxidized lignocellulosic polysaccharides and lignin extensively in vitro under conditions similar to those found in vivo. These results indicate that, in addition to the extensively studied Gloeophyllum trabeum-a model brown rot fungus-other brown rot fungi as well as selective white rot fungi, possess the means to promote Fenton chemistry to degrade cellulose and hemicellulose, and to modify lignin. Moreover, new information is provided, particularly regarding how lignin is attacked, and either repolymerized or solubilized depending on the type of fungal attack, and suggests a new pathway for selective white rot degradation of wood. The importance of Fenton reactions mediated by phenolates operating separately or synergistically with carbohydrate-degrading enzymes in brown rot fungi, and lignin-modifying enzymes in white rot fungi is discussed. This research improves our understanding of natural processes in carbon cycling in the environment, which may enable the exploration of novel methods for bioconversion of lignocellulose in the production of biofuels or polymers, in addition to the development of new and better ways to protect wood from degradation by microorganisms.
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Background & Aims: An elevated transferrin saturation is the earliest phenotypic abnormality in hereditary hemochromatosis. Determination of transferrin saturation remains the most useful noninvasive screening test for affected individuals, but there is debate as to the appropriate screening level. The aims of this study were to estimate the mean transferrin saturation in hemochromatosis heterozygotes and normal individuals and to evaluate potential transferrin saturation screening levels. Methods: Statistical mixture modeling was applied to data from a survey of asymptomatic Australians to estimate the mean transferrin saturation in hemochromatosis heterozygotes and normal individuals. To evaluate potential transferrin saturation screening levels, modeling results were compared with data from identified hemochromatosis heterozygotes and homozygotes. Results: After removal of hemochromatosis homozygotes, two populations of transferrin saturation were identified in asymptomatic Australians (P < 0.01). In men, 88.2% of the truncated sample had a lower mean transferrin saturation of 24.1%, whereas 11.8% had an increased mean transferrin saturation of 37.3%. Similar results were found in women, A transferrin saturation threshold of 45% identified 98% of homozygotes without misidentifying any normal individuals. Conclusions: The results confirm that hemochromatosis heterozygotes form a distinct transferrin saturation subpopulation and support the use of transferrin saturation as an inexpensive screening test for hemochromatosis. In practice, a fasting transferrin saturation of greater than or equal to 45% identifies virtually all affected homozygous subjects without necessitating further investigation of unaffected normal individuals.
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An extensive research program focused on the characterization of various metallurgical complex smelting and coal combustion slags is being undertaken. The research combines both experimental and thermodynamic modeling studies. The approach is illustrated by work on the PbO-ZnO-Al2O3-FeO-Fe2O3-CaO-SiO2 system. Experimental measurements of the liquidus and solidus have been undertaken under oxidizing and reducing conditions using equilibration, quenching, and electron probe X-ray microanalysis. The experimental program has been planned so as to obtain data for thermodynamic model development as well as for pseudo-ternary Liquidus diagrams that can be used directly by process operators. Thermodynamic modeling has been carried out using the computer system FACT, which contains thermodynamic databases with over 5000 compounds and evaluated solution models. The FACT package is used for the calculation of multiphase equilibria in multicomponent systems of industrial interest. A modified quasi-chemical solution model is used for the liquid slag phase. New optimizations have been carried out, which significantly improve the accuracy of the thermodynamic models for lead/zinc smelting and coal combustion processes. Examples of experimentally determined and calculated liquidus diagrams are presented. These examples provide information of direct relevance to various metallurgical smelting and coal combustion processes.
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Background. Increased life expectancy in men during the last thirty years is largely due to the decrease in mortality from cardiovascular disease in the age group 29-69 yr. This change has resulted in a change in the disease profile of the population with conditions such as aneurysm of the abdominal aorta (AAA) becoming more prevalent. The advent of endoluminal treatment for AAA has encouraged prophylactic intervention and fuelled the argument to screen for the disease. The feasibility of inserting an endoluminal graft is dependent on the morphology and growth characteristics of the aneurysm. This study used data from a randomized controlled trial of ultrasound screening for AAA in men aged 65-83 yr in Western Australia for the purpose of determining the norms of the living anatomy in the pressurized infrarenal aorta. Aims. To examine (1) the diameters of the infra-renal aorta in aneurysmal and non-aneurysmal cases, (2) the implications for treatment modalities, with particular reference to endoluminal grafting, which is most dependent on normal and aneurysmal morphology, and (3) any evidence to support the notion that northern Europeans are predisposed to aneurysmal disease. Methods. Using ultrasound, a randomized control trial was established in Western Australia to assess the value of a screening program in males aged 65-83 yr, The infra-renal aorta was defined as aneurysmal if the maximum diameter was 30 mm or more. Aortic diameter was modelled both as a continuous tin mm) and as a binary outcome variable, for those men who had an infra-renal diameter of 30 mm or more. ANOVA and linear regression were used for modelling aortic diameter as a continuum, while chi-square analysis and logistic regression were used in comparing men with and without the diagnosis of AAA. Findings. By December 1998, of 19.583 men had been invited to undergo ultrasound screening for AAA, 12.203 accepted the invitation (corrected response fraction 70.8%). The prevalence of AAA increased with age from 4.8% at 65 yr to 10.8% at 80 yr (chi (2) = 77.9, df = 3, P<0.001). The median (IQR) diameter for the non-aneurysmal group was 21.4 mm (3.3 mm) and there was an increase (<chi>(2) = 76.0, df = 1, P<0.001) in the diameter of the infra-renal aorta with age. Since 27 mm is the 95th centile for the non-aneurysmal infra-renal aorta, a diameter of 30 mm or more is justified as defining an aneurysm. The risk of AAA was higher in men of Australian (OR = 1.0) and northern European origin (OR = 1.0, 95%CL: 0.9. 1.2) compared with those of Mediterranean origin (OR = 0.5, 99%CL: 0.4, 0.7). Conclusion. Although screening has not yet been shown to reduce mortality from AAA. these population-based data assist the understanding of aneurysmal disease and the further development and use of endoluminal grafts for this condition. (C) 2001 Published by Elsevier Science Ltd on behalf of The International Society for Cardiovascular Surgery.
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The present work describes the crystal structure, vibrational spectra, and theoretical calculations of ammonium salts of 3,5-bis-(dicyanomethylene)cyclopentane-1,2,4-trionate, (NH(4))(2)(C(11)N(4)O(3)) [(NH(4))(2)CV], also known as ammonium croconate violet. This compound crystallizes in triclinic P (1) over bar and contains two water molecules per unit formula. The crystal packing is stabilized by hydrogen bonds involving water molecules and ammonium cations, giving rise to a 3D polymeric arrangement. In this structure, a pi-stacking interaction is not observed, as the smaller centroid-centroid distance is 4.35 angstrom. Ab initio electronic structure calculations under periodic boundary conditions were performed to predict vibrational and electronic properties. The vibrational analysis was used to assist the assignments of the Raman and infrared bands. The solid structure was optimized and characterized as a minimum in the potential-energy surface. The stabilizing intermolecular hydrogen bonds in the crystal Structure were characterized by difference charge-density analysis. The analysis of the density of states of (NH(4))(2)CV gives an energy gap of 1.4 eV with a significant contribution of carbon and nitrogen 2p states for valence and conduction bands.
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The purpose of this study is to analyze the Controllership relevance as support risk management in non-financial companies. Risk management is a widely discussed and disseminated subject amongst financial institutions. It is obvious that economic uncertainties and, consequently, prevention and. control must also exist in non-financial companies. To enable managers to take safe-decisions, it is essential for them to be able to count on instrumental support that provides timely and adequate information, to ensure lower levels of mistakes and risk exposure. However, discussion concerning risk management in non-financial companies is still in its early stages in Brazil. Considering this gap, this study aims at assessing how Controllership has been acting in? companies under the insight of risk and how it can contribute to risk management in non-financial companies. To achieve the proposed goal, a field research was. carried-out with non-financial companies that are located in the city Sao Paulo and listed in the Sao Paulo Stock Exchange (Bovespa). The research was carried out using questionnaires, which were sent do Risk Officers and Controllers of those companies with the purpose of evaluating their perception on the subject. The results,of the research allow us to conclude that Controllership offers support to risk management, through information that contributes to the mitigation of the risks in non-financial companies.
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The in vitro inhibitory activity of crude EtOH/H(2)O extracts from the leaves and stems of Rosmarinus officinalis L. was evaluated against the following microorganisms responsible for initiating dental caries: Streptococcus mutans, salivarius, S. sobrinus, S. mitts 5 sanguinis, and Enterococcus faecalis. Minimum inhibitory concentrations (MIC) were determined with the broth microdilution method. The bioassay-guided fractionation of the leaf extract, which displayed the higher antibacterial activity than the stem extract, led to the identification of carnosic acid (2) and carnosol (3) as the major compounds in the fraction displaying the highest activity, as identified by HPLC analysis. Rosmarinic acid (1), detected in another fraction, did not display any activity against the selected microorganisms. HPLC Analysis revealed the presence of low amounts of ursolic acid (4) and oleanolic acid (5) in the obtained fractions. The results suggest that the antimicrobial activity of the extract from the leaves of R. officinalis may be ascribed mainly to the action of 2 and 3.