123 resultados para Operational constraints


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There has been little research on geochemistry and isotopic compositions in tholeiites of the Northern region from the Paraná Continental Flood Basalts (PCFB), one of the largest continental provinces of the world. In order to examine the mantle sources involved in the high-Ti (Pitanga and Paranapanema) basalt genesis, we studied Sr, Nd, and Pb isotopic systematics, and major, minor and incompatible trace element abundances. The REE patterns of the investigated samples (Pitanga and Paranapanema magma type) are similar (parallel to) to those of Island Arc Basalts' REE patterns. The high-Ti basalts investigated in this study have initial (133Ma) 87Sr/86Sr ratios of 0.70538-0.70642, 143Nd/144Nd of 0.51233-0.51218, 206Pb/204Pb of 17.74-18.25, 207Pb/204Pb of 15.51-15.57, and 208Pb/204Pb of 38.18-38.45. These isotopic compositions do not display any correlation with Nb/Th, Nb/La or P2O5/K2O ratios, which also reflect that these rocks were not significantly affected by low-pressure crustal contamination. The incompatible trace element ratios and Sr-Nd-Pb isotopic compositions of the PCFB tholeiites are different to those found in Tristan da Cunha ocean island rocks, showing that this plume did not play a substantial role in the PCFB genesis. This interpretation is corroborated by previously published osmium isotopic data (initial γOs values range from+1.0 to+2.0 for high-Ti basalts), which also preclude basalt generation by melting of ancient subcontinental lithospheric mantle. The geochemical composition of the northern PCFB may be explained through the involvement of fluids and/or small volume melts related to metasomatic processes. In this context, we propose that the source of these magmas is a mixture of sublithospheric peridotite veined and/or interlayered with mafic components (e.g., pyroxenites or eclogites). The sublithospheric mantle (dominating the osmium isotopic compositions) was very probably enriched by fluids and/or magmas related to the Neoproterozoic subduction processes. This sublithospheric mantle region may have been frozen and coupled to the base of the Parana basin lithospheric plate above which the Paleozoic subsidence and subsequent Early Cretaceous magmatism occurred. © 2013 Elsevier Ltd.

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Pós-graduação em Engenharia Elétrica - FEIS

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This paper reports on a process to validate a revised version of a system for coding classroom discourse in foreign language lessons, a context in which the dual role of language (as content and means of communication) and the speakers' specific pedagogical aims lead to a certain degree of ambiguity in language analysis. The language used by teachers and students has been extensively studied, and a framework of concepts concerning classroom discourse well-established. Models for coding classroom language need, however, to be revised when they are applied to specific research contexts. The application and revision of an initial framework can lead to the development of earlier models, and to the re-definition of previously established categories of analysis that have to be validated. The procedures followed to validate a coding system are related here as guidelines for conducting research under similar circumstances. The advantages of using instruments that incorporate two types of data, that is, quantitative measures and qualitative information from raters' metadiscourse, are discussed, and it is suggested that such procedure can contribute to the process of validation itself, towards attaining reliability of research results, as well as indicate some constraints of the adopted research methodology.

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Pós-graduação em Engenharia Elétrica - FEIS

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Objectives To consensually validate the operational definitions of the nursing diagnoses activity intolerance, excessive fluid volume, and decreased cardiac output in patients with decompensated heart failure. Method Consensual validation was performed in two stages: analogy by similarity of defining characteristics, and development of operational definitions and validation with experts. Results A total of 38 defining characteristics were found. Operational definitions were developed and content-validated. One hundred percent of agreement was achieved among the seven experts after five rounds. Ascites was added in the nursing diagnosis excessive fluid volume. Conclusion The consensual validation improves interpretation of human response, grounding the selection of nursing interventions and contributing to improved nursing outcomes. Implications for Practice Support the assessment of patients with decompensated heart failure. Objetivos Realizar a validacAo consensual das definicoes operacionais dos diagnosticos de enfermagem Intolerancia a atividade, Volume de liquidos excessivo e Debito cardiaco diminuido em pacientes com insuficiencia cardiaca descompensada. Metodo ValidacAo consensual em duas etapas: Analogia de semelhanca das caracteristicas definidoras e desenvolvimento de definicoes operacionais e validacAo com expertst. Resultados Foram encontradas 38 caracteristicas definidoras para os diagnosticos de enfermagem. Suas definicoes operacionais foram desenvolvidas e seu conteudo validado. Os resultados mostram que houve 100% de concordancia entre os sete experts apos cinco rodada. As definicoes operacionais foram classificadas com base no nivel de concordanica. Ascite foi acrescentada ao diagnostico Volume de liquidos excessivo. ConclusAo A validacAo consensual melhora a interpretacAo das respostas humanas, embasando a selecAo de intervencoes de enfermagem e contribuindo para melhorar os resultados. Implicacoes Para A Pratica Apoio a avaliacAo dos pacientes com insuficiencia cardiaca descompensada.

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Chemoreception is among the most important sensory modalities in animals. Organisms use the ability to perceive chemical compounds in all major ecological activities. Recent studies have allowed the characterization of chemoreceptor gene families. These genes present strikingly high variability in copy numbers and pseudogenization degrees among different species, but the mechanisms underlying their evolution are not fully understood. We have analyzed the functional networks of these genes, their orthologs distribution, and performed phylogenetic analyses in order to investigate their evolutionary dynamics. We have modeled the chemosensory networks and compared the evolutionary constraints of their genes in Mus musculus, Homo sapiens, and Rattus norvegicus. We have observed significant differences regarding the constraints on the orthologous groups and network topologies of chemoreceptors and signal transduction machinery. Our findings suggest that chemosensory receptor genes are less constrained than their signal transducing machinery, resulting in greater receptor diversity and conservation of information processing pathways. More importantly, we have observed significant differences among the receptors themselves, suggesting that olfactory and bitter taste receptors are more conserved than vomeronasal receptors.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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This paper is concerned with what a source precisely sees when it drives a receiver such as a continuous structural object. An equivalent lumped element system consisting of masses, springs and dampers is developed to visually represent the operational structural dynamics of a single-input structure at the driving point. The development is solely based on the mobility model of the driving point response. The mobility model is mathematically inverted to give the impedance model that is suitable for lumped element modeling. The two types of structures studied are unconstrained inertial objects and constrained resilient objects. The lumped element systems presented suggest a new view to dynamics that a single-input flexible structure in operation can be decomposed into the two subsystems: a base system of single degree of freedom (or of a mass for an inertial object) whose mass is in contact with the source and an appendage system consisting of a series of oscillators each of which is attached to the base mass. The driving point response is a result of the coupling between the two subsystems. (C) 2014 Elsevier Ltd. All rights reserved.

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