Undersampled Critical Branching Processes on Small-World and Random Networks Fail to Reproduce the Statistics of Spike Avalanches

The power-law size distributions obtained experimentally for neuronal avalanches are an important evidence of criticality in the brain. This evidence is supported by the fact that a critical branching process exhibits the same exponent t~3=2. Models at criticality have been employed to mimic avalanche propagation and explain the statistics observed experimentally. However, a crucial aspect of neuronal recordings has been almost completely neglected in the models: undersampling. While in a typical multielectrode array hundreds of neurons are recorded, in the same area of neuronal tissue tens of thousands of neurons can be found. Here we investigate the consequences of undersampling in models with three different topologies (two-dimensional, small-world and random network) and three different dynamical regimes (subcritical, critical and supercritical). We found that undersampling modifies avalanche size distributions, extinguishing the power laws observed in critical systems. Distributions from subcritical systems are also modified, but the shape of the undersampled distributions is more similar to that of a fully sampled system. Undersampled supercritical systems can recover the general characteristics of the fully sampled version, provided that enough neurons are measured. Undersampling in two-dimensional and small-world networks leads to similar effects, while the random network is insensitive to sampling density due to the lack of a well-defined neighborhood. We conjecture that neuronal avalanches recorded from local field potentials avoid undersampling effects due to the nature of this signal, but the same does not hold for spike avalanches. We conclude that undersampled branching-process-like models in these topologies fail to reproduce the statistics of spike avalanches.

Undersampled Critical Branching Processes on Small-World and Random Networks Fail to Reproduce the Statistics of Spike Avalanches

The power-law size distributions obtained experimentally for neuronal avalanches are an important evidence of criticality in the brain. This evidence is supported by the fact that a critical branching process exhibits the same exponent t~3=2. Models at criticality have been employed to mimic avalanche propagation and explain the statistics observed experimentally. However, a crucial aspect of neuronal recordings has been almost completely neglected in the models: undersampling. While in a typical multielectrode array hundreds of neurons are recorded, in the same area of neuronal tissue tens of thousands of neurons can be found. Here we investigate the consequences of undersampling in models with three different topologies (two-dimensional, small-world and random network) and three different dynamical regimes (subcritical, critical and supercritical). We found that undersampling modifies avalanche size distributions, extinguishing the power laws observed in critical systems. Distributions from subcritical systems are also modified, but the shape of the undersampled distributions is more similar to that of a fully sampled system. Undersampled supercritical systems can recover the general characteristics of the fully sampled version, provided that enough neurons are measured. Undersampling in two-dimensional and small-world networks leads to similar effects, while the random network is insensitive to sampling density due to the lack of a well-defined neighborhood. We conjecture that neuronal avalanches recorded from local field potentials avoid undersampling effects due to the nature of this signal, but the same does not hold for spike avalanches. We conclude that undersampled branching-process-like models in these topologies fail to reproduce the statistics of spike avalanches.

Atuação do enfermeiro na rede básica de saúde frente a gestante com infecção do trato urinário

The Urinary Tract Infection (UTI) in pregnancy is important as a consequence of the high incidence during the gestation. It is the third most common clinical complication in pregnancy affecting 10-12% of women whether prevalence is increasing in the first trimester of pregnancy, it may also contribute to maternal and infant mortality. Due the relevance for the results of obstetric and neonatal complications from UTI, these complications must be prevented, because it can lead to health hazards to pregnant women and newborns, producing a direct effect on morbidity and perinatal mortality. On this basis, it was defined as objectives of this research the identification of the profile of nurses from the Family Health Strategy (FHS) in the East and West Health Districts from the city of Natal / RN before the women with UTI and to verify the nurse performance during prenatal consultations. This is an exploratory study with a quantitative approach using a sample of 40 nurses active workers during this survey, it was approved by the Research Ethics Committee of the Universidade Federal do Rio Grande do Norte Protocol n0 232/10 P-CEP/UFRN and opinion n0 080/2011. The tool for data collection was a structured interview. The data collected were organized into an electronic database application Microsoft ® Excel 2007, exported and analyzed using the Statistical Package for Social Sciences (SPSS) version 17.0, and coded, tabulated and presented through tables and charts into their respective percentage distributions, using the descriptive and inferential statistical analysis, chi-square test and significance level of 5% (distribution in relative and absolute frequencies) in the independent variables. Therefore, it was observed from these results that the longer action of nurses in the FHS from the East and Weast health districts of the city of Natal/RN contributed to the development of a greater number of activities to control the incidence of UTI in women who are attended in the prenatal care service, proven by significance in statistics

Formação de caudas maxwellianas no Contexto da rotação estelar

In this Thesis, we analyzed the formation of maxwellian tails of the distributions of the rotational velocity in the context of the out of equilibrium Boltzmann Gibbs statistical mechanics. We start from a unified model for the angular momentum loss rate which made possible the construction of a general theory for the rotational decay in the which, finally, through the compilation between standard Maxwellian and the relation of rotational decay, we defined the (_, _) Maxwellian distributions. The results reveal that the out of equilibrium Boltzmann Gibbs statistics supplies us results as good as the one of the Tsallis and Kaniadakis generalized statistics, besides allowing fittings controlled by physical properties extracted of the own theory of stellar rotation. In addition, our results point out that these generalized statistics converge to the one of Boltzmann Gibbs when we inserted, in your respective functions of distributions, a rotational velocity defined as a distribution