Gambling against neglect: unconscious spatial biases induced by reward reinforcement in healthy people and brain-damaged patients.

Orienting attention in space recruits fronto-parietal networks whose damage results in unilateral spatial neglect. However, attention orienting may also be governed by emotional and motivational factors; but it remains unknown whether these factors act through a modulation of the fronto-parietal attentional systems or distinct neural pathways. Here we asked whether attentional orienting is affected by learning about the reward value of targets in a visual search task, in a spatially specific manner, and whether these effects are preserved in right-brain damaged patients with left spatial neglect. We found that associating rewards with left-sided (but not right-sided) targets during search led to progressive exploration biases towards left space, in both healthy people and neglect patients. Such spatially specific biases occurred even without any conscious awareness of the asymmetric reward contingencies. These results show that reward-induced modulations of space representation are preserved despite a dysfunction of fronto-parietal networks associated with neglect, and therefore suggest that they may arise through spared subcortical networks directly acting on sensory processing and/or oculomotor circuits. These effects could be usefully exploited for potentiating rehabilitation strategies in neglect patients.

Robust pole assignment and optimal stability margins

A robust pole assignment by linear state feedback is achieved in state-space representation by selecting a feedback which minimises the conditioning of the assigned eigenvalues of the closed-loop system. It is shown here that when this conditioning is minimised, a lower bound on the stability margin in the frequency domain is maximised.

O reino encantado do sertão: uma crítica da produção e do fechamento da representação do sertão no romance de Ariano Suassuna

Based on the relation history, literature and space, this work examines the production and the closing of the representation of the hinterland in the Romance d A Pedra do Reino of the paraiban writer Ariano Suassuna. Inspired by method proposed by deconstructionist by Jacques Derrida, our reflection decomposes the writing scene of Suassuna by means of it s tracks to interpret the operation of the representation of the space-hinterland for the speech of the writer. Being thus, we present the elements chosen for Suassuna to weave an identification it s with this space-hinterland, taking a priori as a sentimental place and of familiar origin . The construction of this relation of belonging in great is measured grounded for a familiar memory entangled in the context politician who culminated in the Revolution of 1930 and that he resulted for the writer in the death of father. Suassuna launches a look on the identity and the Brazilian culture that guided in the tradition concept it searchs to deny the gift grounding its speech in the return to the past, a past order . Specifically in it s romance we notice to exist the fusing of these tracks in the production of a representation of the hinterland that it intends to close a concept of this space and its culture. Soon, the idea of kingdom sends to the space of the enchantments manufactured in infancy and retaken by the intellectual radical who in the anxiety of honor the father figure, does not save efforts in constructing a space representation that, over all, either faithful the representation that it searchs to trace of proper itself. Under one it marks of universality , the hinterland-kingdom of Suassuna if discloses eurocentric in the measure where it perpetuates discurse the filiation of the European cultural traditions.

O sertão virou verso, o verso virou sertão:sertão e sertanejos representados e ressignificados pela Literatura de Cordel (1900-1940)

Backland¹ are not only geographic spaces limited by physically established borders. It is a space composed by events, experiences, behavior, symbology, manners related to how to live and see the world. It is developed from historical processes and layers of discourses that contact each other, compete among themselves, establish agreement, promote consensus which define, resignify and update them over time. The present paper seeks to analyze and discuss the forms in which discourses produced by cordel literature² sold and consumed in popular locations, from backlands to coast cities, during the first four decades of 20th century, represented the environment, habits, moral codes, cultural traits, social types, rites and beliefs, related to northeastern backlands. The paper also aims to investigate the forms on how discourses produced by representations contributed to the constitution of backlands as a space culturally constructed. Poems from the poet and editor João Martins de Athayde will be used to establish dialogues between discourses produced by cordel and others discursive modalities, such as, newspapers, prose literature, painting, texts of memoirists and historiography, about backlands, analyzing how those representations circulated, were consumed and absorbed by backlands and other spaces inhabitants, contacted and agreed with other types of discourse, supporting the establishment of backlands as a space and countryside people as a social type

Quantum coherent tunneling between two atomic-molecular Bose-Einstein condensates

We study the quantum coherent tunneling dynamics of two weakly coupled atomic-molecular Bose-Einstein condensates (AMBEC). A weak link is supposed to be provided by a double-well trap. The regions of parameters where the macroscopic quantum localization of the relative atomic population occurs are revealed. The different dynamical regimes are found depending on the value of nonlinearity, namely, coupled oscillations of population imbalance of atomic and molecular condensate, including irregular oscillations regions, and macroscopic quantum self trapping regimes. Quantum means and quadrature variances are calculated for population of atomic and molecular condensates and the possibility of quadrature squeezing is shown via stochastic simulations within P-positive phase space representation method. Linear tunnel coupling between two AMBEC leads to correlations in quantum statistics.

Irreducibility and compositeness in q-deformed harmonic oscillator algebras

A study of the reducibility of the Fock space representation of the q-deformed harmonic oscillator algebra for real and root of unity values of the deformation parameter is carried out by using the properties of the Gauss polynomials. When the deformation parameter is a root of unity, an interesting result comes out in the form of a reducibility scheme for the space representation which is based on the classification of the primitive or nonprimitive character of the deformation parameter. An application is carried out for a q-deformed harmonic oscillator Hamiltonian, to which the reducibility scheme is explicitly applied.

Many-body theory for systems of composite hadrons

Many-body systems of composite hadrons are characterized by processes that involve the simultaneous presence of hadrons and their constituents. We briefly review several methods that have been devised to study such systems and present a novel method that is based on the ideas of mapping between physical and ideal Fock spaces. The method, known as the Fock-Tani representation, was invented years ago in the context of atomic physics problems and was recently extended to hadronic physics. Starting with the Fock-space representation of single-hadron states, a change of representation is implemented by a unitary transformation such that composites are redescribed by elementary Bose and Fermi field operators in an extended Fock space. When the unitary transformation is applied to the microscopic quark Hamiltonian, effective, Hermitian Hamiltonians with a clear physical interpretation are obtained. The use of the method in connection with the linked-cluster formalism to describe short-range correlations and quark deconfinement effects in nuclear matter is discussed. As an application of the method, an effective nucleon-nucleon interaction is derived from a constituent quark model and used to obtain the equation of state of nuclear matter in the Hartree-Fock approximation.

Mapping of composite hadrons into elementary hadrons and effective hadronic Hamiltonians

A mapping technique is used to derive in the context of constituent quark models effective Hamiltonians that involve explicit hadron degrees of freedom. The technique is based on the ideas of mapping between physical and ideal Fock spaces and shares similarities with the quasiparticle method of Weinberg. Starting with the Fock-space representation of single-hadron states, a change of representation is implemented by a unitary transformation such that composites are redescribed by elementary Bose and Fermi field operators in an extended Fock space. When the unitary transformation is applied to the microscopic quark Hamiltonian, effective, hermitian Hamiltonians with a clear physical interpretation are obtained. Applications and comparisons with other composite-particle formalisms of the recent literature are made using the nonrelativistic quark model. (C) 1998 Academic Press.

Employing 2D Projections for Fast Visual Exploration of Large Fiber Tracking Data

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Second quantization approach to composite hadron interactions in quark models

Starting from the Fock space representation of hadron bound states in a quark model, a change of representation is implemented by a unitary transformation such that the composite hadrons are redescribed by elementary-particle field operators. Application of the unitary transformation to the microscopic quark Hamiltonian gives rise to effective hadron-hadron, hadron-quark, and quark-quark Hamiltonians. An effective baryon Hamiltonian is derived using a simple quark model. The baryon Hamiltonian is free of the post-prior discrepancy which usually plagues composite-particle effective interactions.

Inclusão do efeito da frequência nas equações de estado de linhas bifásicas: análise no domínio do tempo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A experiência como fator determinante na representação espacial do deficiente visual

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Modelagem geoestatística por geoprocessamento em uma área da Baixada Santista

Pós-graduação em Geociências e Meio Ambiente - IGCE

Técnica de projeto de controlador fuzzy aplicada ao acionamento vetorial de motor de indução

Este trabalho investiga uma estratégia de controle fuzzy Takagi-Sugeno aplicada ao controle de velocidade do motor de indução. A estratégia implementa uma interpolação ponderada entre um conjunto de controladores locais previamente projetados. Ao ocorrer variações nas condições operacionais do motor de indução, os ganhos da lei de controle são ajustados automaticamente, de modo a manter satisfatório o desempenho do sistema de controle. Para o projeto do controlador fuzzy a representação em espaço de estados da planta foi considerada sob a forma de um sistema aumentado, incluindo-se uma nova variável de estado que, nesse caso, foi selecionada como sendo a integral do erro de velocidade. Tal formulação permitiu o projeto de controladores locais com a estrutura PI, através de realimentação completa de estados, com posicionamento de pólos. Como variáveis de operação para o chaveamento fuzzy dos controladores locais, foram selecionados as variáveis velocidade angular do rotor e a componente da corrente de estator responsável pelo torque elétrico do motor. Em seguida, a estabilidade do controlador fuzzy Takagi- Sugeno projetado foi comprovada através do critério de Lyapunov, para isso o problema de estabilidade foi escrito na forma de LMIs. O desempenho do controlador fuzzy Takagi-Sugeno foi avaliado através de estudos de simulação, e seus resultados comparados ao desempenho de um controlador PI convencional, para a regulação da velocidade do rotor. Os resultados obtidos nas simulações mostram que o emprego da estratégia proposta torna o sistema mais robusto a variações paramétricas no sistema de acionamento.

A desmaterialização do espaço: um estudo das interfaces entre a produção ficcional e as teorias da pós-modernidade

Pós-graduação em Estudos Literários - FCLAR