863 resultados para Colour Theories
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Includes bibliography
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We study the local properties of a class of codimension-2 defects of the 6d N = (2, 0) theories of type J = A, D, E labeled by nilpotent orbits of a Lie algebra $g, where g is determined by J and the outer-automorphism twist around the defect. This class is a natural generalization of the defects of the six-dimensional (6d) theory of type SU(N) labeled by a Young diagram with N boxes. For any of these defects, we determine its contribution to the dimension of the Higgs branch, to the Coulomb branch operators and their scaling dimensions, to the four-dimensional (4d) central charges a and c and to the flavor central charge k. © 2013 World Scientific Publishing Company.
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Includes bibliography
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Includes bibliography
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We explore the idea that chaos concepts might be useful for understanding the thermalization in gauge theories. The SU(2) Higgs model is discussed as a prototype of system with gauge fields coupled to matter fields. Through the numerical solution of the equations of motion, we are able to characterize chaotic behavior via the corresponding Lyapunov exponent. Then it is demonstrated that the system's approach to equilibrium can be understood through direct application of the principles of Statistical Mechanics. © 2013 AIP Publishing LLC.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Os testes Colour Assessment and Diagnosis (CAD) e Cambridge Colour Test (CCT) têm sido amplamente utilizados em pesquisas básicas e clínicas, devido à alta sensibilidade e especificidade de seus resultados. Estes testes utilizam diferentes paradigmas de estimulação para estimar os limiares de discriminação de cor. Pouco se sabe sobre a relação de cada paradigma na avaliação da discriminação de cor nesses testes. Sendo assim, este trabalho objetiva comparar os parâmetros de avaliação da discriminação de cor estimados pelos testes CAD e CCT em sujeitos tricromatas e com discromatopsia congênita. Foram avaliados 59 sujeitos tricromatas e 38 sujeitos discromatópsicos (16 protans, 22 deutans) com idade média de 26,32 ± 8,9 anos. Foram testados 66 sujeitos nos testes CAD e CCT, 29 sujeitos no teste CAD e 2 sujeitos no teste CCT. O fenótipo da visão de cores de todos os sujeitos foi determinado através de uma bateria de testes psicofísicos e a estimativa dos limiares de discriminação de cor foi avaliada pelos testes CAD e CCT. Os dados de limiares de discriminação de cor foram ajustados a funções de elipse. Os critérios analisados para cada sujeito foram: a área da elipse, o ângulo de rotação e tamanho dos vetores protan, deutan e tritan. Para cada um dos parâmetros foi realizada: estatística descritiva, análise da dispersão dos parâmetros entre os testes CAD e CCT e dos parâmetros em conjunto, razão entre os parâmetros, correlação dos parâmetros a três modelos matemáticos e análise de concordância. Os parâmetros de área e tamanho dos vetores deutan e tritan do subgrupo tricromata; área e tamanho do vetor tritan do subgrupo protan; e tamanho dos vetores protan e tritan do subgrupo deutan apresentaram equivalência entre os resultados de ambos os testes. Os parâmetros de área, ângulo de rotação e tamanho dos vetores protan e tritan apresentaram concordância de medidas entre os testes CAD e CCT. Fatores como as localizações distintas das coordenadas centrais dos testes CAD e CCT e a disposição espacial dos vetores no espaço de cor da CIE 1976 no teste CCT podem ter influenciado na determinação de limiares de discriminação cromática de ambos os testes. Apesar de utilizarem paradigmas distintos na configuração da estimulação, os testes CAD e CCT são equiparáveis.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The colour stability of acrylic resin denture teeth in beverages was investigated. A spectrophotometer measured the colour (CIE-L*a*b* system) of all specimens after storage in distilled water for 24 h at 37°C (T0). Specimens were then immersed in various beverages. After 15 days (T1) and 30 days (T2), for each material, the mean ∆E values were calculated and compared by two-way ANOVA and Tukey intervals (α=0.05). In the ∆T0T1 period, specimens stored in red wine were significantly discoloured, compared to distilled water (P=0.003). There was no difference between immersion solutions in ∆ET0T2 (P=0.772) and in ∆ET1T2 (P=0.058), and no difference between materials in all immersion periods.
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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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We analyze the integrability properties of models defined on the symmetric space SU(2)/U(1) in 3 + 1 dimensions, using a recently proposed approach for integrable theories in any dimension. We point out the key ingredients for a theory to possess an infinite number of local conservation laws, and discuss classes of models with such property, We propose a 3 + 1-dimensional, relativistic invariant field theory possessing a toroidal soliton solution carrying a unit of topological charge given by the Hopf map. Construction of the action is guided by the requirement that the energy of static configuration should be scale invariant. The solution is constructed exactly. The model possesses an infinite number of local conserved currents. The method is also applied to the Skyrme-Faddeev model, and integrable submodels are proposed. (C) 1999 Elsevier B.V. B.V. All rights reserved.
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Theories proposed by Chickering, Astin, Helms, Gilligan, and Perry serve as a framework for under¬standing and explaining the development of college students.
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Color vision impairment emerges at early stages of diabetes mellitus type 2 (DM2) and may precede diabetic retinopathy or the appearance of vascular alterations in the retina. The aim of the present study was to compare the evaluation of the color vision with two different tests - the Lanthony desaturated D-15d test (a traditional color arrangement test), and the Cambridge Colour Test (CCT) (a computerized color discrimination test) - in patients diagnosed with DM2 without clinical signs of diabetic retinopathy (DR), and in sex- and age-matched control groups. Both color tests revealed statistically significant differences between the controls and the worst eyes of the DM2 patients. In addition, the degree of color vision impairment diagnosed by both tests correlated with the disease duration. The D-15d outcomes indicated solely tritan losses. In comparison, CCT outcomes revealed diffuse losses in color discrimination: 13.3% for best eyes and 29% for worst eyes. In addition, elevation of tritan thresholds in the DM2 patients, as detected by the Trivector subtest of the CCT, was found to correlate with the level of glycated hemoglobin. Outcomes of both tests confirm that subclinical losses of color vision are present in DM2 patients at an early stage of the disease, prior to signs of retinopathy. Considering the advantages of the CCT test compared to the D-15d test, further studies should attempt to verify and/or improve the efficiency of the CCT test.