Tempos de tunelamento

Pós-graduação em Física - IFT

Twistor-like constraints for the superparticle and the superstring

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise do processo de formação como mediadora entre o público e a arte

The proposed work is located in education field in exhibition spaces of art and seeks to analyze a process of formation as a mediator focusing on the public's relationship with art, taking into account the fact that often the general public does not dominate the codes of this area, being incumbent upon mediator introduce them. One of the main points to be analyzed is the impact that can be generated by the contact of the visitor with the mediator in the exhibition space, considering a spectrum of possibilities, where at one end focuses the belonging and in the other the symbolic violence. In this direction this research aims to build a relationship of emancipation and autonomy of both, the educator and the visitor. It is known that the concept of public is a generalization, therefore, the analysis of the mediation process, are having as support the experiences lived by the mediator, especially, in the relationship with the lay public. The locations of the experiences lived, were the SESC Pompéia and the Pavilion of the Bienal of São Paulo, different places, but both with the potential to generate reception and / or distances, shot through space (architecture), bodies, codes, accesses, works of art, repertoires, expographic and especially through the mobilization of educator front of all these issues. The cutting of the research covers the experience of the educator (as an intern and professional) in six exhibitions, in these two spaces, between the years 2010 to 2015.

Ensino de leitura de sentenças: contribuições da análise do comportamento

O paradigma da equivalência de estímulos tem sido pouco usado para estudar o ensino de leitura de sentenças. Assim, o presente estudo avaliou o efeito de um procedimento de ensino e testes de relações condicionais seguidos pelo encadeamento de palavras sobre a leitura com compreensão de sentenças e a generalização de leitura. Participaram oito escolares, com 7 e 9 anos de idade. O procedimento incluiu pré e pós-teste, três fases de ensino e testes de leitura com compreensão, um teste de conectividade e um teste de construção de sentenças. A leitura de palavras e de sentenças melhorou do pré para o pós-teste em todos os casos, demonstrando que o procedimento foi efetivo para ensinar leitura com compreensão de sentenças.

Twistor-like constraints for the superparticle and the superstring

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise do processo de formação como mediadora entre o público e a arte

The proposed work is located in education field in exhibition spaces of art and seeks to analyze a process of formation as a mediator focusing on the public's relationship with art, taking into account the fact that often the general public does not dominate the codes of this area, being incumbent upon mediator introduce them. One of the main points to be analyzed is the impact that can be generated by the contact of the visitor with the mediator in the exhibition space, considering a spectrum of possibilities, where at one end focuses the belonging and in the other the symbolic violence. In this direction this research aims to build a relationship of emancipation and autonomy of both, the educator and the visitor. It is known that the concept of public is a generalization, therefore, the analysis of the mediation process, are having as support the experiences lived by the mediator, especially, in the relationship with the lay public. The locations of the experiences lived, were the SESC Pompéia and the Pavilion of the Bienal of São Paulo, different places, but both with the potential to generate reception and / or distances, shot through space (architecture), bodies, codes, accesses, works of art, repertoires, expographic and especially through the mobilization of educator front of all these issues. The cutting of the research covers the experience of the educator (as an intern and professional) in six exhibitions, in these two spaces, between the years 2010 to 2015.

The Kumaraswamy Gumbel distribution

The Gumbel distribution is perhaps the most widely applied statistical distribution for problems in engineering. We propose a generalization-referred to as the Kumaraswamy Gumbel distribution-and provide a comprehensive treatment of its structural properties. We obtain the analytical shapes of the density and hazard rate functions. We calculate explicit expressions for the moments and generating function. The variation of the skewness and kurtosis measures is examined and the asymptotic distribution of the extreme values is investigated. Explicit expressions are also derived for the moments of order statistics. The methods of maximum likelihood and parametric bootstrap and a Bayesian procedure are proposed for estimating the model parameters. We obtain the expected information matrix. An application of the new model to a real dataset illustrates the potentiality of the proposed model. Two bivariate generalizations of the model are proposed.

On d- and D-separability

In this article we study relationships between d-separability and D-separability and present conditions under which these concepts are equivalent. We also study their relationship with D+-separability and define a generalization of discrete generability. (C) 2012 Elsevier B.V. All rights reserved.

A relaxed constant positive linear dependence constraint qualification and applications

In this work we introduce a relaxed version of the constant positive linear dependence constraint qualification (CPLD) that we call RCPLD. This development is inspired by a recent generalization of the constant rank constraint qualification by Minchenko and Stakhovski that was called RCRCQ. We show that RCPLD is enough to ensure the convergence of an augmented Lagrangian algorithm and that it asserts the validity of an error bound. We also provide proofs and counter-examples that show the relations of RCRCQ and RCPLD with other known constraint qualifications. In particular, RCPLD is strictly weaker than CPLD and RCRCQ, while still stronger than Abadie's constraint qualification. We also verify that the second order necessary optimality condition holds under RCRCQ.

Estimation and diagnostics for heteroscedastic nonlinear regression models based on scale mixtures of skew-normal distributions

An extension of some standard likelihood based procedures to heteroscedastic nonlinear regression models under scale mixtures of skew-normal (SMSN) distributions is developed. This novel class of models provides a useful generalization of the heteroscedastic symmetrical nonlinear regression models (Cysneiros et al., 2010), since the random term distributions cover both symmetric as well as asymmetric and heavy-tailed distributions such as skew-t, skew-slash, skew-contaminated normal, among others. A simple EM-type algorithm for iteratively computing maximum likelihood estimates of the parameters is presented and the observed information matrix is derived analytically. In order to examine the performance of the proposed methods, some simulation studies are presented to show the robust aspect of this flexible class against outlying and influential observations and that the maximum likelihood estimates based on the EM-type algorithm do provide good asymptotic properties. Furthermore, local influence measures and the one-step approximations of the estimates in the case-deletion model are obtained. Finally, an illustration of the methodology is given considering a data set previously analyzed under the homoscedastic skew-t nonlinear regression model. (C) 2012 Elsevier B.V. All rights reserved.

Towards automated first-order abduction: the cut-based approach

Traditional abduction imposes as a precondition the restriction that the background information may not derive the goal data. In first-order logic such precondition is, in general, undecidable. To avoid such problem, we present a first-order cut-based abduction method, which has KE-tableaux as its underlying inference system. This inference system allows for the automation of non-analytic proofs in a tableau setting, which permits a generalization of traditional abduction that avoids the undecidable precondition problem. After demonstrating the correctness of the method, we show how this method can be dynamically iterated in a process that leads to the construction of non-analytic first-order proofs and, in some terminating cases, to refutations as well.

Phenol biodegradation by a microbial consortium: application of artificial neural network (ANN) modelling

In this study, an effective microbial consortium for the biodegradation of phenol was grown under different operational conditions, and the effects of phosphate concentration (1.4 g L-1, 2.8 g L-1, 4.2 g L-1), temperature (25 degrees C, 30 degrees C, 35 degrees C), agitation (150 rpm, 200 rpm, 250 rpm) and pH (6, 7, 8) on phenol degradation were investigated, whereupon an artificial neural network (ANN) model was developed in order to predict degradation. The learning, recall and generalization characteristics of neural networks were studied using data from the phenol degradation system. The efficiency of the model generated by the ANN was then tested and compared with the experimental results obtained. In both cases, the results corroborate the idea that aeration and temperature are crucial to increasing the efficiency of biodegradation.

Social phobia in obsessive-compulsive disorder: Prevalence and correlates

Background: Social Phobia (SP) is an anxiety disorder that frequently co-occurs with obsessive-compulsive disorder (OCD); however, studies that evaluate clinical factors associated with this specific comorbidity are rare. The aim was to estimate the prevalence of SP in a large multicenter sample of OCD patients and compare the characteristics of individuals with and without SP. Method: A cross-sectional study with 1001 patients of the Brazilian Research Consortium on Obsessive-Compulsive Spectrum Disorders using several assessment instruments, including the Dimensional Yale-Brown Obsessive-Compulsive Scale and the Structured Clinical Interview for DSM-IV Axis I Disorders. Univariate analyses were followed by logistic regression. Results: Lifetime prevalence of SP was 34.6% (N=346). The following variables remained associated with SP comorbidity after logistic regression: male sex, lower socioeconomic status, body dysmorphic disorder, specific phobia, dysthymia, generalized anxiety disorder, agoraphobia, Tourette syndrome and binge eating disorder. Limitations: The cross-sectional design does not permit the inference of causal relationships; some retrospective information may have been subject to recall bias; all patients were being treated in tertiary services, therefore generalization of the results to other samples of OCD sufferers should be cautious. Despite the large sample size, some hypotheses may not have been confirmed due to the small number of cases with these characteristics (type 2 error). Conclusion: SP is frequent among OCD patients and co-occurs with other disorders that have common phenomenological features. These findings have important implications for clinical practice, indicating the need for broader treatment approaches for individuals with this profile. (C) 2012 Elsevier B.V. All rights reserved.

On the zeros of polynomials: an extension of the Enestrom-Kakeya theorem

This paper presents an extension of the Enestrom-Kakeya theorem concerning the roots of a polynomial that arises from the analysis of the stability of Brown (K, L) methods. The generalization relates to relaxing one of the inequalities on the coefficients of the polynomial. Two results concerning the zeros of polynomials will be proved, one of them providing a partial answer to a conjecture by Meneguette (1994)[6]. (C) 2011 Elsevier Inc. All rights reserved.

Reproductive biology of the ghost shrimp Lepidophthalmus bocourti (A. Milne-Edwards, 1870) (Decapoda: Axiidea: Callianassidae): A tropical species with a seasonal reproduction

Based on the hypothesis that reproduction is a continuous process in tropical habitats, we analysed reproductive periodicity and egg production in the callianassid ghost shrimp Lepidophthalmus bocourti, one of the most common species in mangrove systems along the Pacific coast of Central America. During one year (May 2008 to April 2009), individuals of L. bocourti (N = 499) were collected nearshore Gulf of Nicoya, Pacific coast of Costa Rica. Observations were made on presence or absence of incubated embryos, and gonad activity of females was analysed as gonadosomatic index (GSI). Our results revealed that L. bocourti has a marked seasonal breeding period, which contradicts previous reports regarding coastal marine decapods from the tropics. Ovigerous females were found only from June to August, while high GSI values were obtained from March to July. The increase of GSI and appearance of ovigerous females were associated with a concomitant decrease of salinity, but not with temperature. We assume that reproduction of L. bocourti is adapted to local changes of environmental conditions, and that a decrease in salinity during rainy season may serve as a triggering factor for ovarian development. Compared to other ghost shrimps, L. bocourti produced on average more (2002 +/- 1365) and smaller (0.87 +/- 0.109 mm) eggs, which seems to suggest that this species does not have an abbreviated larval development as reported for other species of genus. The deviation from the generalization of constant reproduction in the tropics for shallow water marine invertebrates and its probable cause are adequately discussed.