Vanishing Viscosity Limits and Boundary Layers for Circularly Symmetric 2D Flows

We continue the work of Lopes Filho, Mazzucato and Nussenzveig Lopes [LMN], on the vanishing viscosity limit of circularly symmetric viscous flow in a disk with rotating boundary, shown there to converge to the inviscid limit in $L^2$-norm as long as the prescribed angular velocity $\alpha(t)$ of the boundary has bounded total variation. Here we establish convergence in stronger $L^2$ and $L^p$-Sobolev spaces, allow for more singular angular velocities $\alpha$, and address the issue of analyzing the behavior of the boundary layer. This includes an analysis of concentration of vorticity in the vanishing viscosity limit. We also consider such flows on an annulus, whose two boundary components rotate independently. [LMN] Lopes Filho, M. C., Mazzucato, A. L. and Nussenzveig Lopes, H. J., Vanishing viscosity limit for incompressible flow inside a rotating circle, preprint 2006

Neural networks with dynamical synapses: from mixed-mode oscillations and spindles to chaos

Understanding of short-term synaptic depression (STSD) and other forms of synaptic plasticity is a topical problem in neuroscience. Here we study the role of STSD in the formation of complex patterns of brain rhythms. We use a cortical circuit model of neural networks composed of irregular spiking excitatory and inhibitory neurons having type 1 and 2 excitability and stochastic dynamics. In the model, neurons form a sparsely connected network and their spontaneous activity is driven by random spikes representing synaptic noise. Using simulations and analytical calculations, we found that if the STSD is absent, the neural network shows either asynchronous behavior or regular network oscillations depending on the noise level. In networks with STSD, changing parameters of synaptic plasticity and the noise level, we observed transitions to complex patters of collective activity: mixed-mode and spindle oscillations, bursts of collective activity, and chaotic behaviour. Interestingly, these patterns are stable in a certain range of the parameters and separated by critical boundaries. Thus, the parameters of synaptic plasticity can play a role of control parameters or switchers between different network states. However, changes of the parameters caused by a disease may lead to dramatic impairment of ongoing neural activity. We analyze the chaotic neural activity by use of the 0-1 test for chaos (Gottwald, G. & Melbourne, I., 2004) and show that it has a collective nature.Comment: 7 pages, Proceedings of 12th Granada Seminar, September 17-21, 201

Critical and resonance phenomena in neural networks

Brain rhythms contribute to every aspect of brain function. Here, we study critical and resonance phenomena that precede the emergence of brain rhythms. Using an analytical approach and simulations of a cortical circuit model of neural networks with stochastic neurons in the presence of noise, we show that spontaneous appearance of network oscillations occurs as a dynamical (non-equilibrium) phase transition at a critical point determined by the noise level, network structure, the balance between excitatory and inhibitory neurons, and other parameters. We find that the relaxation time of neural activity to a steady state, response to periodic stimuli at the frequency of the oscillations, amplitude of damped oscillations, and stochastic fluctuations of neural activity are dramatically increased when approaching the critical point of the transition.Comment: 8 pages, Proceedings of 12th Granada Seminar, September 17-21, 201

Enriched elderly virtual profiles by means of a multidimensional integrated assessment platform

The pressure over Healthcare systems is increasing in most developed countries. The generalized aging of the population is one of the main causes. This situation is even worse in underdeveloped, sparsely populated regions like Extremadura in Spain or Alentejo in Portugal. The authors propose to use the Situational-Context, a technique to seamlessly adapt Internet of Things systems to the needs and preferences of their users, for virtually modeling the elderly. These models could be used to enhance the elderly experience when using those kind of systems without raising the need for technical skills or the costs of implementing such systems by the regional healthcare systems. In this paper, the integration of a multidimensional integrated assessment platform with such virtual profiles is presented. The assessment platform provides and additional source of information for the virtual profiles that is used to better adapt existing systems to the elders needs

EDUCAÇÃO SEXUAL NA ESCOLA – CONTEXTOS PARA A MUDANÇA

A educação sexual é hoje uma das áreas de intervenção prioritária no nosso País e ocupa um lugar de interesse no âmbito das políticas educativas e de saúde pública na União Europeia. Diversos estudos têm sido desenvolvidos abordando a problemática da sexualidade na adolescência( 1,2,3,4), os quais constatam a precocidade do início das relações sexuais entre os adolescentes, a inexistência de um parceiro sexual regular e a reduzida utilização sistemática do preservativo nas situações de risco acrescido. Perante este panorama tornam-se relevantes as intervenções de educação sexual dirigidas aos indivíduos nesta fase da vida. Até porque é inquestionável o papel crucial que a sexualidade desempenha no crescimento e desenvolvimento do adolescente, no relacionamento interpessoal, no respeito, na comunicação, na autoestima, na assertividade e na autoconfiança. Face ao exposto optou-se pela metodologia de investigação ação. Na fase diagnóstica procedeu-se à aplicação de um conjunto de instrumentos dos quais destacamos o questionário: avaliação de atitudes dos professores face á Educação sexual (QAAPES)(5); conceções e práticas face à Educação sexual – versão para professores(6). Os resultados apresentados reportam-se apenas à primeira fase do processo. Os mesmos permitiram-nos constatar o reconhecimento da educação sexual na escola como uma necessidade explícita. Na opinião dos professores esta diz respeito a todos os professores e deve ser abordada preferencialmente na componente letiva. Para estes a principal finalidade da educação sexual é desenvolver as competências dos alunos para que consigam viver a sua sexualidade de uma forma mais saudável

The bright side of the dark side: covert politics as an alternative to the negative impacts of coercive change

This study examines practitioners as individual actors by focusing on a general manager's individual account. With a two-week episode of political maneuvering as a starting point, the case shows how skilful strategizing on the part of the general manager is at the origin of significant organizational change. Specifically, the paper has three purposes. First, to offer insights to practitioners and scholars regarding how powerful managers purposefully seek to influence organizational context in a non-disclosed fashion. Second, to illustrate how single case microstudies open a route to understanding events that would otherwise be unattainable. The third, and most important, is to apply organizational politics concepts to characterize managerial covert political action in the implementation of a deliberate strategy. Specifically, emphasis is put on how contextual characteristics relate to political action. How they constrain and enable politics, and facilitate the use and maintenance of concealed motives

Cuidados domiciliares – interacção do enfermeiro com a pessoa idosa/família

Objetivo: Compreender o processo de interacção com a pessoa idosa e família no domicílio desenvolvido pelos enfermeiros. Métodos: Estudo de natureza qualitativa, Grounded Theory, em uma comunidade onde 40% da população têm idade igual ou superior a 65 anos. A coleta dos dados foi pela observação não participante das práticas de enfermagem, durante 41 visitas domiciliárias e entrevistas semiestruturadas às enfermeiras, pessoa idosa e família. Resultados: Emergiram as categorias: organização estrutural dos cuidados domiciliares, avaliação diagnóstica em con- texto e intervenção terapêutica em contexto. Conclusão: A categoria central foi “Construindo a relação em contexto domiciliar” pelo fato da relação da enfermeira com o idoso e a família ser central em todo o processo de cuidados. A relação é simultaneamente o contexto de todos os cuidados, assim como é um instrumento terapêutico