Dinâmica da Plasticidade Sináptica em neurônios do hipocampo durante ciclos de sono: um estudo computacional

Several research lines show that sleep favors memory consolidation and learning. It has been proposed that the cognitive role of sleep is derived from a global scaling of synaptic weights, able to homeostatically restore the ability to learn new things, erasing memories overnight. This phenomenon is typical of slow-wave sleep (SWS) and characterized by non-Hebbian mechanisms, i.e., mechanisms independent of synchronous neuronal activity. Another view holds that sleep also triggers the specific enhancement of synaptic connections, carrying out the embossing of certain mnemonic traces within a lattice of synaptic weights rescaled each night. Such an embossing is understood as the combination of Hebbian and non-Hebbian mechanisms, capable of increasing and decreasing respectively the synaptic weights in complementary circuits, leading to selective memory improvement and a restructuring of synaptic configuration (SC) that can be crucial for the generation of new behaviors ( insights ). The empirical findings indicate that initiation of Hebbian plasticity during sleep occurs in the transition of the SWS to the stage of rapid eye movement (REM), possibly due to the significant differences between the firing rates regimes of the stages and the up-regulation of factors involved in longterm synaptic plasticity. In this study the theories of homeostasis and embossing were compared using an artificial neural network (ANN) fed with action potentials recorded in the hippocampus of rats during the sleep-wake cycle. In the simulation in which the ANN did not apply the long-term plasticity mechanisms during sleep (SWS-transition REM), the synaptic weights distribution was re-scaled inexorably, for its mean value proportional to the input firing rate, erasing the synaptic weights pattern that had been established initially. In contrast, when the long-term plasticity is modeled during the transition SWSREM, an increase of synaptic weights were observed in the range of initial/low values, redistributing effectively the weights in a way to reinforce a subset of synapses over time. The results suggest that a positive regulation coming from the long-term plasticity can completely change the role of sleep: its absence leads to forgetting; its presence leads to a positive mnemonic change

O papel da violência interpessoal compreendida como a manifestação de uma endemia social: uma análise geográfica sobre o fenômeno no Brasil e Rio Grande do Norte

En Brasil, la violencia interpersonal (homicidios) se ha incrementado de forma significativa, convirtiéndose en una preocupación cada vez mayor en todos los ámbitos políticos de la sociedad. Hoy es uno de los más graves problemas sociales y de salud pública. Se refiere a los problemas sociales, ya que interfiere en la distribución de la oferta de bienes y servicios a los ciudadanos; sino también un problema de salud, porque la violencia es uno de los fenómenos que causan gran impacto en la morbilidad y mortalidad del país, y genera un alto costo para el Sistema Único de Saúde (SUS). Esta es una crisis social, que es el resultado de un mundo capitalista globalizado, que exige a todos sus instrumentos de dominación (dinero, poder y competitividad en estado puro), en virtud del cual la violencia y los conflictos interpersonales se materializan en el territorio. El Río Grande do Norte (RN) ha estado siguiendo esta realidad que es nacional, con el aumento de las tasas de mortalidad por homicidios. En este sentido, este estudio tuvo como objetivo analizar la violencia interpersonal (agresión / homicidio), en Brasil y en el estado del RN, para entender cómo esto afecta a su población, en la morbilidad y mortalidad durante los años 2001 a 2011. Para ambos hicimos uso de método descriptivo / cuantitativo para determinar la magnitud, el tamaño, el perfil de las víctimas y los costos del SUS generados por el problema. Como resultado, podemos diagnosticar que en Brasil, la violencia se ha presentado una nueva dinámica regional, promovida por un proceso de interiorización del fenómeno en todo el país, este proceso de internalización se ha reflejado en la última década, el crecimiento de la violencia en el estado del RN, que ha causado un gran impacto en las tasas de la mortalidad del estado. Acerca la victimización, se puede ver que hay un perfil vulnerable formado por, varón, baja instrucción joven, sola y negro. Con respecto a los datos de morbilidad hospitalaria, la demanda creciente del fenómeno genera costes para el sistema de salud, y las graves consecuencias humanas, como la escalada del miedo y la destrucción de una generación de jóvenes brasileños. Por lo tanto, la falta de una política pública para afrontamiento, prevención y mitigación del problema revela el fracaso de la gestión pública, con consecuencias sociales y de salud, tanto individual como colectivamente.

Obtenção, caracterização e utilização de um compósito com matriz de resina poliéster e carga de fibras de sisal

The constant search for sustainable alternatives has earned great effort of researchers in research and obtaining new materials, encouraging the rise of eco-friendly productive development and providing simple and practical solutions to economic profitability. In this sense, the use of materials derived from natural renewable sources, vegetables, has great potential applicability to sustainable development. As alternative materials plant fibers can be applied to production of a range of composite materials easing the use of materials derived from non-renewable this thesis were sisal mats used for achieving a composite matrix having as one orthophthalic polyester resin. The webs were subjected to surface treatment in boiling water for 15 minutes. The webs of sisal fibers used were, respectively, 5%, 10% and 15% of the composite weight. The composite was obtained and characterized mechanically and thermally to the chosen formulations. several plates of the composite to obtain the body of evidence for the characterization tests complying with the relevant rules were made. The obtained composites showed strength tensile and bending lower than the array, so it can be used where are required low load requests. The most significant result of the composite studied given to the impact energy absorption, far superior to the matrix used. Other properties were highlighted in oil absorption, and density. It proved the feasibility of obtaining the composite for the three formulations studied C5, C10 and C15 being the most feasible to C10. To demonstrate the feasibility of using composite were made a wall clock, a bench, a chair and a shelf, low mechanical stress structures. It was concluded that the sisal rugs exercised the load function in the composite.

Obtenção, caracterização e utilização de um compósito com matriz de resina poliéster e carga de fibras de sisal

The constant search for sustainable alternatives has earned great effort of researchers in research and obtaining new materials, encouraging the rise of eco-friendly productive development and providing simple and practical solutions to economic profitability. In this sense, the use of materials derived from natural renewable sources, vegetables, has great potential applicability to sustainable development. As alternative materials plant fibers can be applied to production of a range of composite materials easing the use of materials derived from non-renewable this thesis were sisal mats used for achieving a composite matrix having as one orthophthalic polyester resin. The webs were subjected to surface treatment in boiling water for 15 minutes. The webs of sisal fibers used were, respectively, 5%, 10% and 15% of the composite weight. The composite was obtained and characterized mechanically and thermally to the chosen formulations. several plates of the composite to obtain the body of evidence for the characterization tests complying with the relevant rules were made. The obtained composites showed strength tensile and bending lower than the array, so it can be used where are required low load requests. The most significant result of the composite studied given to the impact energy absorption, far superior to the matrix used. Other properties were highlighted in oil absorption, and density. It proved the feasibility of obtaining the composite for the three formulations studied C5, C10 and C15 being the most feasible to C10. To demonstrate the feasibility of using composite were made a wall clock, a bench, a chair and a shelf, low mechanical stress structures. It was concluded that the sisal rugs exercised the load function in the composite.