964 resultados para Two dimensions
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This article investigates how teachers in religious education (RE) think and act as professionals while working with differences in religious and philosophy of life experiences and beliefs in class and trying to do this in respectful and inclusive ways. It analyses data from two research projects that were carried out in lower secondary school in Norway. The main research question is: What is the relationship between teachers’ contextual knowledge and knowledge of the child and how do these two dimensions of professional knowledge interact when religious education teachers try to strike a good balance between inclusion and productive learning in their teaching practice? The data analysed were drawn from three different data sets featuring three Norwegian religious education-teachers. The research was part of the EU-funded "REDCo"-project and the "Religious education and diversity" - project ["ROM"] funded by the Norwegian Research Council. The interviewees emphasized the potential of the religious education subject to contribute to a wider tolerance for difference and to support individual students in their identity management. The analysis shows, however, that considerable contextual awareness - of the classroom and of the local community - is needed to realize this potential. It also shows the importance of interpersonal knowledge between the teacher and each student if contextual awareness is to be effective in terms of inclusion, participation, wellbeing and good learning outcomes for all students.
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La modélisation de la cryolite, utilisée dans la fabrication de l’aluminium, implique plusieurs défis, notament la présence de discontinuités dans la solution et l’inclusion de la difference de densité entre les phases solide et liquide. Pour surmonter ces défis, plusieurs éléments novateurs ont été développés dans cette thèse. En premier lieu, le problème du changement de phase, communément appelé problème de Stefan, a été résolu en deux dimensions en utilisant la méthode des éléments finis étendue. Une formulation utilisant un multiplicateur de Lagrange stable spécialement développée et une interpolation enrichie a été utilisée pour imposer la température de fusion à l’interface. La vitesse de l’interface est déterminée par le saut dans le flux de chaleur à travers l’interface et a été calculée en utilisant la solution du multiplicateur de Lagrange. En second lieu, les effets convectifs ont été inclus par la résolution des équations de Stokes dans la phase liquide en utilisant la méthode des éléments finis étendue aussi. Troisièmement, le changement de densité entre les phases solide et liquide, généralement négligé dans la littérature, a été pris en compte par l’ajout d’une condition aux limites de vitesse non nulle à l’interface solide-liquide pour respecter la conservation de la masse dans le système. Des problèmes analytiques et numériques ont été résolus pour valider les divers composants du modèle et le système d’équations couplés. Les solutions aux problèmes numériques ont été comparées aux solutions obtenues avec l’algorithme de déplacement de maillage de Comsol. Ces comparaisons démontrent que le modèle par éléments finis étendue reproduit correctement le problème de changement phase avec densités variables.
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O presente estudo procura testar as propriedades psicométricas de um questionário que avalia (a) perceção do aluno sobre o feedback do professor; a identificação escolar do aluno; as trajetórias escolares (factos e expectativas) e; a perceção do aluno sobre o seu envolvimento escolar. O questionário foi aplicado a 1089 alunos dos 6º, 7º, 9º e 10º anos de escolaridade (M=13.4, DP=1.7), sendo que 52% são do sexo feminino. A amostra é composta por alunos essencialmente de nacionalidade portuguesa (95.9%). A partir dos resultados da análise factorial e seguindo o racional teórico, chegou-se a uma estrutura composta por oito dimensões principais. O QFITE apresenta bons índices de consistência interna, com sete das oito principais dimensões a obterem valores entre .77 e .89. Assim, as análises psicométricas realizadas revelam valores satisfatórios, concluindo-se que o QFITE é um instrumento útil e adequado para avaliar a identificação escolar dos alunos, o envolvimento comportamental escolar, e as perceções dos alunos sobre o feedback do professor.
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Calcium ions are an important second messenger in living cells. Indeed calcium signals in the form of waves have been the subject of much recent experimental interest. It is now well established that these waves are composed of elementary stochastic release events (calcium puffs or sparks) from spatially localised calcium stores. The aim of this paper is to analyse how the stochastic nature of individual receptors within these stores combines to create stochastic behaviour on long timescales that may ultimately lead to waves of activity in a spatially extended cell model. Techniques from asymptotic analysis and stochastic phase-plane analysis are used to show that a large cluster of receptor channels leads to a release probability with a sigmoidal dependence on calcium density. This release probability is incorporated into a computationally inexpensive model of calcium release based upon a stochastic generalization of the Fire-Diffuse-Fire (FDF) threshold model. Numerical simulations of the model in one and two dimensions (with stores arranged on both regular and disordered lattices) illustrate that stochastic calcium release leads to the spontaneous production of calcium sparks that may merge to form saltatory waves. Illustrations of spreading circular waves, spirals and more irregular waves are presented. Furthermore, receptor noise is shown to generate a form of array enhanced coherence resonance whereby all calcium stores release periodically and simultaneously.
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Neural field models of firing rate activity have had a major impact in helping to develop an understanding of the dynamics seen in brain slice preparations. These models typically take the form of integro-differential equations. Their non-local nature has led to the development of a set of analytical and numerical tools for the study of waves, bumps and patterns, based around natural extensions of those used for local differential equation models. In this paper we present a review of such techniques and show how recent advances have opened the way for future studies of neural fields in both one and two dimensions that can incorporate realistic forms of axo-dendritic interactions and the slow intrinsic currents that underlie bursting behaviour in single neurons.
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Single-walled carbon nanotubes (SWNTs) have been studied as a prominent class of high performance electronic materials for next generation electronics. Their geometry dependent electronic structure, ballistic transport and low power dissipation due to quasi one dimensional transport, and their capability of carrying high current densities are some of the main reasons for the optimistic expectations on SWNTs. However, device applications of individual SWNTs have been hindered by uncontrolled variations in characteristics and lack of scalable methods to integrate SWNTs into electronic devices. One relatively new direction in SWNT electronics, which avoids these issues, is using arrays of SWNTs, where the ensemble average may provide uniformity from device to device, and this new breed of electronic material can be integrated into electronic devices in a scalable fashion. This dissertation describes (1) methods for characterization of SWNT arrays, (2) how the electrical transport in these two-dimensional arrays depend on length scales and spatial anisotropy, (3) the interaction of aligned SWNTs with the underlying substrate, and (4) methods for scalable integration of SWNT arrays into electronic devices. The electrical characterization of SWNT arrays have been realized by polymer electrolyte-gated SWNT thin film transistors (TFTs). Polymer electrolyte-gating addresses many technical difficulties inherent to electrical characterization by gating through oxide-dielectrics. Having shown polymer electrolyte-gating can be successfully applied on SWNT arrays, we have studied the length scaling dependence of electrical transport in SWNT arrays. Ultrathin films formed by sub-monolayer surface coverage of SWNT arrays are very interesting systems in terms of the physics of two-dimensional electronic transport. We have observed that they behave qualitatively different than the classical conducting films, which obey the Ohm’s law. The resistance of an ultrathin film of SWNT arrays is indeed non-linear with the length of the film, across which the transport occurs. More interestingly, a transition between conducting and insulating states is observed at a critical surface coverage, which is called percolation limit. The surface coverage of conducting SWNTs can be manipulated by turning on and off the semiconductors in the SWNT array, leading to the operation principle of SWNT TFTs. The percolation limit depends also on the length and the spatial orientation of SWNTs. We have also observed that the percolation limit increases abruptly for aligned arrays of SWNTs, which are grown on single crystal quartz substrates. In this dissertation, we also compare our experimental results with a two-dimensional stick network model, which gives a good qualitative picture of the electrical transport in SWNT arrays in terms of surface coverage, length scaling, and spatial orientation, and briefly discuss the validity of this model. However, the electronic properties of SWNT arrays are not only determined by geometrical arguments. The contact resistances at the nanotube-nanotube and nanotube-electrode (bulk metal) interfaces, and interactions with the local chemical groups and the underlying substrates are among other issues related to the electronic transport in SWNT arrays. Different aspects of these factors have been studied in detail by many groups. In fact, I have also included a brief discussion about electron injection onto semiconducting SWNTs by polymer dopants. On the other hand, we have compared the substrate-SWNT interactions for isotropic (in two dimensions) arrays of SWNTs grown on Si/SiO2 substrates and horizontally (on substrate) aligned arrays of SWNTs grown on single crystal quartz substrates. The anisotropic interactions associated with the quartz lattice between quartz and SWNTs that allow near perfect horizontal alignment on substrate along a particular crystallographic direction is examined by Raman spectroscopy, and shown to lead to uniaxial compressive strain in as-grown SWNTs on single crystal quartz. This is the first experimental demonstration of the hard-to-achieve uniaxial compression of SWNTs. Temperature dependence of Raman G-band spectra along the length of individual nanotubes reveals that the compressive strain is non-uniform and can be larger than 1% locally at room temperature. Effects of device fabrication steps on the non-uniform strain are also examined and implications on electrical performance are discussed. Based on our findings, there are discussions about device performances and designs included in this dissertation. The channel length dependences of device mobilities and on/off ratios are included for SWNT TFTs. Time response of polymer-electrolyte gated SWNT TFTs has been measured to be ~300 Hz, and a proof-of-concept logic inverter has been fabricated by using polymer electrolyte gated SWNT TFTs for macroelectronic applications. Finally, I dedicated a chapter on scalable device designs based on aligned arrays of SWNTs, including a design for SWNT memory devices.
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A natural way to generalize tensor network variational classes to quantum field systems is via a continuous tensor contraction. This approach is first illustrated for the class of quantum field states known as continuous matrix-product states (cMPS). As a simple example of the path-integral representation we show that the state of a dynamically evolving quantum field admits a natural representation as a cMPS. A completeness argument is also provided that shows that all states in Fock space admit a cMPS representation when the number of variational parameters tends to infinity. Beyond this, we obtain a well-behaved field limit of projected entangled-pair states (PEPS) in two dimensions that provide an abstract class of quantum field states with natural symmetries. We demonstrate how symmetries of the physical field state are encoded within the dynamics of an auxiliary field system of one dimension less. In particular, the imposition of Euclidean symmetries on the physical system requires that the auxiliary system involved in the class' definition must be Lorentz-invariant. The physical field states automatically inherit entropy area laws from the PEPS class, and are fully described by the dissipative dynamics of a lower dimensional virtual field system. Our results lie at the intersection many-body physics, quantum field theory and quantum information theory, and facilitate future exchanges of ideas and insights between these disciplines.
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Projeto de Investigação apresentado para a obtenção do grau de Mestre em Psicologia do Desporto e do Exercício
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Purpose: as exposure to psychosocial hazard at work represents a substantial risk factor for employee health in many modern occupations, being able to accurately assess how employees cope with their working environment is crucial. As the workplace is generally accepted as being a dynamic environment consideration should be given to the interaction between employees and the acute environmental characteristics of their workplace. The aim of this study was to investigate the effects of both acute demand and chronic work-related psychosocial hazard upon employees through ambulatory assessment of heart rate variability and blood pressure. Design: a within-subjects repeated measures design was used to investigate the relationship between exposure to work-related psychosocial hazard and ambulatory heart rate variability and blood pressure in a cohort of higher education employees. Additionally the effect of acute variation in perceived work-related demand was investigated. Results: two dimensions of the Management Standards were found to demonstrate an association with heart rate variability; more hazardous levels of “demand” and “relationships” were associated with decreased SDNN. Significant changes in blood pressure and indices of heart rate variability were observed with increased acute demand.
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Many of the equations describing the dynamics of neural systems are written in terms of firing rate functions, which themselves are often taken to be threshold functions of synaptic activity. Dating back to work by Hill in 1936 it has been recognized that more realistic models of neural tissue can be obtained with the introduction of state-dependent dynamic thresholds. In this paper we treat a specific phenomenological model of threshold accommodation that mimics many of the properties originally described by Hill. Importantly we explore the consequences of this dynamic threshold at the tissue level, by modifying a standard neural field model of Wilson-Cowan type. As in the case without threshold accommodation classical Mexican-Hat connectivity is shown to allow for the existence of spatially localized states (bumps) in both one and two dimensions. Importantly an analysis of bump stability in one dimension, using recent Evans function techniques, shows that bumps may undergo instabilities leading to the emergence of both breathers and traveling waves. Moreover, a similar analysis for traveling pulses leads to the conditions necessary to observe a stable traveling breather. In the regime where a bump solution does not exist direct numerical simulations show the possibility of self-replicating bumps via a form of bump splitting. Simulations in two space dimensions show analogous localized and traveling solutions to those seen in one dimension. Indeed dynamical behavior in this neural model appears reminiscent of that seen in other dissipative systems that support localized structures, and in particular those of coupled cubic complex Ginzburg-Landau equations. Further numerical explorations illustrate that the traveling pulses in this model exhibit particle like properties, similar to those of dispersive solitons observed in some three component reaction-diffusion systems. A preliminary account of this work first appeared in S Coombes and M R Owen, Bumps, breathers, and waves in a neural network with spike frequency adaptation, Physical Review Letters 94 (2005), 148102(1-4).
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Pela importância atual – e crescente – que o vinho tem na economia portuguesa, pela margem existente para a apresentação de temas de reflexão que acrescentem valor ao posicionamento do setor, pela experiência pessoal e paixão pela área, decidi elaborar a minha dissertação numa temática enquadrável no setor do vinho, em particular no vinho Alvarinho proveniente do terroir que representa a Denominação de Origem Vinho Verde Sub-região de Monção e Melgaço. A estrutura deste estudo assenta em duas dimensões: a primeira, numa perspetiva local, assente na recente decisão de alargar a Denominação Origem Vinho Verde Alvarinho a todas as sub-regiões que integram a Região dos Vinhos Verdes, com efeitos em 2021. Pelo que se procurará mostrar a importância da relação desta casta com o seu terroir de origem e, perante esta interligação, qual o fator mais importante a utilizar na comunicação do vinho. A segunda prende-se com a dimensão internacional que se pretende para o Alvarinho no mercado dos grandes vinhos brancos mundiais, onde encontramos castas brancas de renome como a Chardonnay e a Riesling, face a esta exposição e à crescente aposta na casta a nível mundial, como agir perante a potencial ameaça que representa a entrada dos países do “Novo Mundo”. Posto isto, é neste contexto que se coloca a questão que está na génese desta dissertação: de que forma o terroir contribui como fator de diferenciação e de vantagem competitiva do Alvarinho produzido na Denominação de Origem Vinho Verde Sub-região Monção e Melgaço no mercado dos grandes vinhos brancos mundiais? Cuja resposta poderá em grande parte estar, no meu entendimento, na análise de um caso de sucesso, que nesta dissertação é representada pelo trabalho realizado em torno do Rieseling produzido no Vale de Mosel e que contribuiu para que este tivesse conquistado a sua reputação.
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Os contornos de um mundo em mudança e a evolução do pensamento há muito que se afastaram dos conceitos de identidades unas e imutáveis. A própria aceitação da mutabilidade traduz-se também nos cenários das vastas possibilidades para os fenómenos identitários à escala global. Também por isso, e mais do que nunca, se revela preponderante a reflexão sobre tais fenómenos identitários e a compreensão da sua intervenção e pertinência nas constantes reconfigurações sociais da atualidade. Esse será o universo do presente trabalho, onde serão auscultadas atuais conceções identitárias e o seu lugar no caso português. Este estudo configura-se, portanto, a partir de objetivos centrais bem delimitados: identificar e caracterizar a eventual existência de identidades regionais em Portugal, no caso particular dos territórios associados a Viseu. Este ponto de partida surge da análise da frequente cartografia das identidades territoriais na realidade portuguesa, bem como da continuidade de anteriores estudos do autor. Com efeito, verifica-se que frequentemente se definem duas grandes tipologias identitárias no que concerne à relação com o território: a local e a nacional. Tal posição surge em aberta contradição com os discursos mediáticos recorrentes onde a constante presença de um discurso de matriz regional obriga à dúvida inevitável. Nesse sentido, falando-se de região, foi necessário percorrer os conceitos de limite e de fronteira que a delimitam e lhe conferem sentido, indagando-se sobre o lugar da sua criação e da sua vivência. Assim, o trabalho orientou-se em dois grandes sentidos iniciais: o do levantamento da ação delimitadora do Estado, tido como autor das demarcações regionais em Portugal e o da auscultação da produção discursiva dos media regionais, agentes e expressão da identidade regional. A segunda dimensão obrigaria a um estudo aturado sobre a imprensa regional, objeto essencial do presente trabalho e a partir do qual será possível alcançar conclusões validáveis para o período entre 1959 e 2011. É então pelo cruzamento das duas dimensões referidas que se surpreende a existência de traços identitários regionais bem vincados, profundamente arreigados ao discurso do Estado Novo, raramente correspondendo aos intentos de delimitação das sucessivas iniciativas governamentais posteriores que, desse modo, revelam também um profundo distanciamento desse território que insistentemente vão dividindo. Entre o discurso eivado de simbolismo – embora centralista – do Estado Novo e as denominações técnicas – embora com o propósito de promover a descentralização do poder – da democracia, o discurso identitário da imprensa regional de Viseu alimenta-se ainda hoje do primeiro. Não porque vise os seus objetivos, mas porque é o que melhor caracteriza uma identidade relativamente pacificada: sempre pronta a recorrer ao passado beirão para afirmar as suas diferenças, sem no entanto pôr em causa o espírito da Nação; sempre pronta a denunciar o centralismo de Lisboa, esquecendo embora que foi esse centralismo que outrora lhe atribuiu a característica da genuinidade de, o que quer que seja, ser português.
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El modelo de evaluación bidimensional MEB en la educación superior, propuesto en este trabajo mide el conocimiento de estudiantes versus grado de certeza. El análisis de estas dos dimensiones permite al profesor determinar áreas de conocimiento a profundizar con sus estudiantes. La investigación fue descriptiva y correlacional, fueron aplicados métodos científico e inductivo. Las técnicas utilizadas fueron cuestionarios y análisis estadístico y recursos técnicos fueron: sistema de gestión de aprendizaje Moodle, software para análisis matemático MATLAB, EXCEL, laboratorios de la Facultad de Informática y Electrónica (FIE) de la Escuela Superior Politécnica de Chimborazo (ESPOCH), institución donde se llevó a cabo el estudio. El MEB propone la aplicación de cuestionarios de selección múltiple con el mecanismo CBM (Certainty based marking - Marcado basado en la certeza), sobre un aula virtual creada en el sistema Moodle. CBM permite medir por cada pregunta de un cuestionario las dimensiones conocimiento y certeza.
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Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2015.
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Este artigo visa testar um hexa-modelo dimensional do empenhamento organizacional sugerido em pesquisas anteriores de Rego (2002b, 2003). O modelo difere do esquema tri-dimensional mais comum (afectivo, normativo e instrumental) no que concerne a três aspectos: a) a faceta afectiva é desmembrada em duas (empenhamento afectivo; futuro comum); b) a faceta instrumental é dividida nas facetas “escassez de alternativas” e “sacrifícios elevados”; c) é sugerida uma nova dimensão, designada “ausência psicológica” e que representa o “grau zero” do empenhamento. A amostra é constituída por 366 indivíduos, com actividades profissionais bastante distintas. Análises factoriais confirmatórias sugerem que o modelo de seis dimensões se ajusta satisfatoriamente aos dados, embora os modelos de quatro e cinco dimensões denotem igualmente boas qualidades psicométricas.