906 resultados para Multi-dimensional scaling
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Os últimos vinte anos caracterizaram-se pela proliferação de tecnologias que tornaram possível decifrar o genoma das espécies, localizar e identificar particularidades na sua seqüência, elucidar as suas funções dentro dos sistemas biológicos e, sobretudo, começar a entender os mecanismos que controlam as interações entre os genótipos e os estímulos ambientais, que são responsáveis pela diversidade fenotípica. Estes estudos sobre as bases moleculares da variabilidade fenotípica abriram uma nova abordagem científica, caracterizada pela multiplicidade das questões envolvidas, que resultou no surgimento de novas áreas de pesquisa, cujos conhecimentos estão sendo aplicados em diversos campos da biologia, inclusive na zootecnia. Tendo em vista o grande impacto que tais conhecimentos estão tendo sobre a compreensão dos fenômenos biológicos, parece ser oportuno fazer uma avaliação das potencialidades de aplicação das abordagens de Genômica Funcional em pesquisas de nutrição e alimentação de ruminantes. Nesse contexto, este artigo está focado na descrição das principais ferramentas genômicas disponíveis e na discussão sobre a viabilidade de se utilizar as informações por elas geradas em benefício da produção animal.
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Analog networks for solving convex nonlinear unconstrained programming problems without using gradient information of the objective function are proposed. The one-dimensional net can be used as a building block in multi-dimensional networks for optimizing objective functions of several variables.
The contribution of biofuels to the sustainability of development in Latin America and the Caribbean
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Includes bibliography
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Incluye Bibliografía
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Much analysis and proposals on sustainable transport policies have been developed around the world, both at government and research institutions. It is clear that no action will provide the single solution and it is imperative to act simultaneously on: i) improvement of technology in vehicles, leading to increased energy efficiency; ii) the change in driver behavior, to use less fuel per kilometer; iii) reducing the distances traveled per vehicle; and iv) a change in the type of travels towards more sustainable modes of transport.In general, the recommendations for energy efficiency in transport are mainly focused on the first two priorities on the list, while the portfolios of policies —instrumental to the needs of the countries— should use trans-sectoral and multi-dimensional approaches, such as public transport planning and land use. In ECLAC, we consider that the time has come to provide Latin American and Caribbean countries with a deeper understanding and a more strategic vision (and adapted to the realities of the region) on these issues; in this sense, we hope that this document will help countries to improve and further expand their portfolios of energy efficiency policies in the transport sector, in order to achieve the ambitious goals of energy efficiency, needed to ensure a sustainable energy future.
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Incluye bibliografía.
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Pós-graduação em Ciências da Motricidade - IBRC
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Pós-graduação em Ciências da Motricidade - IBRC
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Pós-graduação em Educação Matemática - IGCE
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Este trabalho enfoca a problemática da inclusão educacional de alunos com deficiência no ensino regular brasileiro. A partir da revisão sistemática da literatura sobre o tema foi possível apresentar dois estudos. O primeiro tem natureza descritiva, objetivou revisar artigos sobre inclusão de alunos com deficiência no ensino regular brasileiro, a fim de investigar o panorama da pesquisa nessa área. Foi utilizada a revisão sistemática na biblioteca virtual da SciELO, na qual foram selecionados 138 artigos para investigação. Os resultados desse primeiro estudo apontaram que as pesquisas sobre inclusão educacional avançaram a partir do ano de 2005, principalmente nas regiões sudeste e sul, com prevalência de pesquisas empíricas em diversas áreas do conhecimento e com destaque para a educação. O segundo estudo analisou artigos científicos, que tratam da inclusão de alunos com deficiência no ensino regular de acordo com a concepção teórico-metodológica da teoria bioecológica do desenvolvimento humano. A partir da revisão sistemática da literatura e a avalição do instrumento CASP se selecionou 16 artigos que foram analisados a partir do modelo bioecológico PPCT. Observou-se que a partir dos dados apresentados o uso da teoria bioecológica foi útil para investigar pesquisas e sistematizar a organização de trabalhos.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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This study examined how the quality of Leader-Member Exchange (LMX) relationships was moderated by the Constructive-Developmental stage or Order of Consciousness of both leader and follower. Using student organization presidents and officers on a small, private, liberal arts college campus in the Midwest, the researcher used a sample of 37 students to study the impact developmental stage had on the leadership relationship. Using the Leader Member Exchange-Multi-Dimensional Measure (LMX-MDM), four dimensions of LMX were examined. The four dimensions were Affect, Contribution, Loyalty and Professional Respect. There was no significant relationship between Order of Consciousness and quality of LMX relationship. While there was no significant difference in LMX relationship based on gender of participants, there was a significant difference between how male presidents and officers perceived their relationship in the Loyalty dimension. Directions for further research and implications for practice were discussed.
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The inherent stochastic character of most of the physical quantities involved in engineering models has led to an always increasing interest for probabilistic analysis. Many approaches to stochastic analysis have been proposed. However, it is widely acknowledged that the only universal method available to solve accurately any kind of stochastic mechanics problem is Monte Carlo Simulation. One of the key parts in the implementation of this technique is the accurate and efficient generation of samples of the random processes and fields involved in the problem at hand. In the present thesis an original method for the simulation of homogeneous, multi-dimensional, multi-variate, non-Gaussian random fields is proposed. The algorithm has proved to be very accurate in matching both the target spectrum and the marginal probability. The computational efficiency and robustness are very good too, even when dealing with strongly non-Gaussian distributions. What is more, the resulting samples posses all the relevant, welldefined and desired properties of “translation fields”, including crossing rates and distributions of extremes. The topic of the second part of the thesis lies in the field of non-destructive parametric structural identification. Its objective is to evaluate the mechanical characteristics of constituent bars in existing truss structures, using static loads and strain measurements. In the cases of missing data and of damages that interest only a small portion of the bar, Genetic Algorithm have proved to be an effective tool to solve the problem.
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This Doctoral Thesis focuses on the study of individual behaviours as a result of organizational affiliation. The objective is to assess the Entrepreneurial Orientation of individuals proving the existence of a set of antecedents to that measure returning a structural model of its micro-foundation. Relying on the developed measurement model, I address the issue whether some Entrepreneurs experience different behaviours as a result of their academic affiliation, comparing a sample of ‘Academic Entrepreneurs’ to a control sample of ‘Private Entrepreneurs’ affiliated to a matched sample of Academic Spin-offs and Private Start-ups. Building on the Theory of the Planned Behaviour, proposed by Ajzen (1991), I present a model of causal antecedents of Entrepreneurial Orientation on constructs extensively used and validated, both from a theoretical and empirical perspective, in sociological and psychological studies. I focus my investigation on five major domains: (a) Situationally Specific Motivation, (b) Personal Traits and Characteristics, (c) Individual Skills, (d) Perception of the Business Environment and (e) Entrepreneurial Orientation Related Dimensions. I rely on a sample of 200 Entrepreneurs, affiliated to a matched sample of 72 Academic Spin-offs and Private Start-ups. Firms are matched by Industry, Year of Establishment and Localization and they are all located in the Emilia Romagna region, in northern Italy. I’ve gathered data by face to face interviews and used a Structural Equation Modeling technique (Lisrel 8.80, Joreskog, K., & Sorbom, D. 2006) to perform the empirical analysis. The results show that Entrepreneurial Orientation is a multi-dimensional micro-founded construct which can be better represented by a Second-Order Model. The t-tests on the latent means reveal that the Academic Entrepreneurs differ in terms of: Risk taking, Passion, Procedural and Organizational Skills, Perception of the Government, Context and University Supports. The Structural models also reveal that the main differences between the two groups lay in the predicting power of Technical Skills, Perceived Context Support and Perceived University Support in explaining the Entrepreneurial Orientation Related Dimensions.
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This thesis presents a creative and practical approach to dealing with the problem of selection bias. Selection bias may be the most important vexing problem in program evaluation or in any line of research that attempts to assert causality. Some of the greatest minds in economics and statistics have scrutinized the problem of selection bias, with the resulting approaches – Rubin’s Potential Outcome Approach(Rosenbaum and Rubin,1983; Rubin, 1991,2001,2004) or Heckman’s Selection model (Heckman, 1979) – being widely accepted and used as the best fixes. These solutions to the bias that arises in particular from self selection are imperfect, and many researchers, when feasible, reserve their strongest causal inference for data from experimental rather than observational studies. The innovative aspect of this thesis is to propose a data transformation that allows measuring and testing in an automatic and multivariate way the presence of selection bias. The approach involves the construction of a multi-dimensional conditional space of the X matrix in which the bias associated with the treatment assignment has been eliminated. Specifically, we propose the use of a partial dependence analysis of the X-space as a tool for investigating the dependence relationship between a set of observable pre-treatment categorical covariates X and a treatment indicator variable T, in order to obtain a measure of bias according to their dependence structure. The measure of selection bias is then expressed in terms of inertia due to the dependence between X and T that has been eliminated. Given the measure of selection bias, we propose a multivariate test of imbalance in order to check if the detected bias is significant, by using the asymptotical distribution of inertia due to T (Estadella et al. 2005) , and by preserving the multivariate nature of data. Further, we propose the use of a clustering procedure as a tool to find groups of comparable units on which estimate local causal effects, and the use of the multivariate test of imbalance as a stopping rule in choosing the best cluster solution set. The method is non parametric, it does not call for modeling the data, based on some underlying theory or assumption about the selection process, but instead it calls for using the existing variability within the data and letting the data to speak. The idea of proposing this multivariate approach to measure selection bias and test balance comes from the consideration that in applied research all aspects of multivariate balance, not represented in the univariate variable- by-variable summaries, are ignored. The first part contains an introduction to evaluation methods as part of public and private decision process and a review of the literature of evaluation methods. The attention is focused on Rubin Potential Outcome Approach, matching methods, and briefly on Heckman’s Selection Model. The second part focuses on some resulting limitations of conventional methods, with particular attention to the problem of how testing in the correct way balancing. The third part contains the original contribution proposed , a simulation study that allows to check the performance of the method for a given dependence setting and an application to a real data set. Finally, we discuss, conclude and explain our future perspectives.