Ilha das Flores, estatura e peso em crianças dos 6 aos 11 anos.

IV Expedição Científica do Departamento de Biologia – Flores 1989.0s estudos de crescimento físico humano têm-se revelado de grande interesse pois permitem conhecer as características de diferentes populações e a variabilidade existente intra e interpopulações. Mas um dos aspectos mais importantes destes estudos talvez o de, ao se analisar o estado de crescimento e tempo de desenvolvimento do indivíduo, permitir destrinçar factores que influenciam nefastamente o crescimento. As diferenças existentes entre populações são o resultado da interacção do ambiente com os factores genéticos. 0s factores ambientais influênciadores do crescimento são: nutrição, doenças, status sócio-económico, urbanismo, actividade física, stress psicológico, estado do ano e clima. A nutrição é considerado o agente mais influenciador no processo de crescimento (Eveleth, 1979; Malcolm, 1979). Neste estudo consideraram-se a estatura e o peso como os indicadores do crescimento das crianças, de idades entre os 6 e 11 anos, na sua maioria naturais da Ilha das Flores. 0s objectivos foram comparar os valores obtidos com existentes para crianças continentais, descrever a sua variação em função dos indicadores sócio-económicos: profissão do pai, número de irmãos e ordem de nascimento

Neural mechanisms of stimulus generalization in auditory fear conditioning

Dissertation presented to obtain the Ph.D degree in Neuroscience Instituto de Tecnologia Química e Biológica, Universidade Nova de LisboaFear is a physiological trait with a strong weight on survival and adaptation. Great progress has been made to understand the mechanisms of fear learning, mainly using auditory fear conditioning (AFC). In this behavioral paradigm, an initial neutral tone (conditioned stimulus, CS) acquires aversive predictive properties after successive pairings with a footshock (unconditioned stimulus, US) and comes to elicit responses characteristically elicited by threatening stimuli. In this behavioral paradigm, the amygdala has been identified has a key neural substrate for associative fear learning, and the site where unconditioned stimuli (US) and conditioned (CS) auditory stimuli come to be associated. Auditory information may reach the amygdala either directly from the auditory thalamus or indirectly via thalamo-cortico-amygdala projections. The “high route/low route” hypothesis has thus been proposed, which claims that the cortical pathway (“high route”) is crucial for discrimination between fearful and neutral sounds, while the direct thalamic pathway (“low route”) provides a rapid but less accurate relay of auditory information to the amygdala. This hypothesis relies on the assumption that more complex processing requires cortical activity and that thalamic relay is faster then cortical transmission to the amygdala. The present work essentially aims at putting to test this largely accepted hypothesis.Auditory fear conditioning was used as the behavioral paradigm to unravel the possible functional explanation for the coexistence of two parallel auditory pathways converging into the amygdala, and the high route/low route hypothesis was the working model for the identification of neuronal substrates of auditory discrimination.(...)This work was supported by Fundação para a Ciência e a Tecnologia (Grant SFRH/BD/27500/2006)

Agricultores guardiões de sementes e o desenvolvimento in situ de cultivares crioulas.

bitstream/CPACT-2009-09/11716/1/artigo-Bevilaq_sement.pd

A new method based on noise counting to monitor the frontend electronics of the LHCb muon detector

A new method has been developed to check the correct behaviour of the frontend electronics of the LHCb muon detector. This method is based on the measurement of the electronic noise rate at different thresholds of the frontend discriminator. The method was used to choose the optimal discriminator thresholds. A procedure based on this method was implemented in the detector control system and allowed the detection of a small percentage of frontend channels which had deteriorated. A Monte Carlo simulation has been performed to check the validity of the method

The Ginzburg regime and its effects on topological defect formation

The Ginzburg temperature has historically been proposed as the energy scale of formation of topological defects at a second order symmetry breaking phase transition. More recently alternative proposals which compute the time of formation of defects from the critical dynamics of the system, have been gaining both theoretical and experimental support. We investigate, using a canonical model for string formation, how these two pictures compare. In particular we show that prolonged exposure of a critical field configuration to the Ginzburg regime results in no substantial suppression of the final density of defects formed. These results dismiss the recently proposed role of the Ginzburg regime in explaining the absence of topological defects in 4He pressure quench experiments.Comment: 8 pages, 5 ps figure

Predicting the critical density of topological defects in O(N) scalar field theories

O(N) symmetric $\lambda \phi^4$ field theories describe many critical phenomena in the laboratory and in the early Universe. Given N and $D\leq 3$, the dimension of space, these models exhibit topological defect classical solutions that in some cases fully determine their critical behavior. For N=2, D=3 it has been observed that the defect density is seemingly a universal quantity at T_c. We prove this conjecture and show how to predict its value based on the universal critical exponents of the field theory. Analogously, for general N and D we predict the universal critical densities of domain walls and monopoles, for which no detailed thermodynamic study exists. This procedure can also be inverted, producing an algorithm for generating typical defect networks at criticality, in contrast to the canonical procedure, which applies only in the unphysical limit of infinite temperature.Comment: 4 pages, 3 figures, uses RevTex, typos in Eq.(11) and (14) correcte

Vortex Loop Phase Transitions in Liquid Helium, Cosmic Strings, and High-T_c Superconductors

The distribution of thermally excited vortex loops near a superfluid phase transition is calculated from a renormalized theory. The number density of loops with a given perimeter is found to change from exponential decay with increasing perimeter to algebraic decay as T_c is approached, in agreement with recent simulations of both cosmic strings and high-T_c superconductors. Predictions of the value of the exponent of the algebraic decay at T_c and of critical behavior in the vortex density are confirmed by the simulations, giving strong support to the vortex-folding model proposed by Shenoy.Comment: Version to appear in Phys. Rev. Lett, with a number of corrections and addition

Monitoramento da cultura da cana-de-açúcar utilizando a Transformada de Wavelet em séries temporais de dados EVI/MODIS.

O objetivo do trabalho foi realizar o monitoramento da cultura da cana-de-açúcar no noroeste do Estado de São Paulo, utilizando a Transformada de Wavelet em séries temporais de dados EVI/MODIS, do ano de 2005 a 2009.SBSR 2011

The Creation of Defects with Core Condensation

Defects in superfluid 3He, high-Tc superconductors, QCD colour superfluids and cosmic vortons can possess (anti)ferromagnetic cores, and their generalisations. In each case there is a second order parameter whose value is zero in the bulk which does not vanish in the core. We examine the production of defects in the simplest 1+1 dimensional scalar theory in which a second order parameter can take non-zero values in a defect core. We study in detail the effects of core condensation on the defect production mechanism.Comment: 9 pages, 7 figures, small corrections, 2 references added, final version to be published in PR