2,164 research outputs found

    Representações de Egocentrismo (Jogo Simbólico e Linguagem) numa sala de 2 anos durante as atividades livres.

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    Relatório apresentado para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Educação Pré-escolar

    Salivary gland-specific <i>P. berghei</i> reporter lines enable rapid evaluation of tissue-specific sporozoite loads in mosquitoes

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    Malaria is a life-threatening human infectious disease transmitted by mosquitoes. Levels of the salivary gland sporozoites (sgs), the only mosquito stage infectious to a mammalian host, represent an important cumulative index of &lt;i&gt;Plasmodium&lt;/i&gt; development within a mosquito. However, current techniques of sgs quantification are laborious and imprecise. Here, transgenic &lt;i&gt;P. berghei&lt;/i&gt; reporter lines that produce the green fluorescent protein fused to luciferase (GFP-LUC) specifically in sgs were generated, verified and characterised. Fluorescence microscopy confirmed the sgs stage specificity of expression of the reporter gene. The luciferase activity of the reporter lines was then exploited to establish a simple and fast biochemical assay to evaluate sgs loads in whole mosquitoes. Using this assay we successfully identified differences in sgs loads in mosquitoes silenced for genes that display opposing effects on &lt;i&gt;P. berghei&lt;/i&gt; ookinete/oocyst development. It offers a new powerful tool to study infectivity of &lt;i&gt;P. berghei&lt;/i&gt; to the mosquito, including analysis of vector-parasite interactions and evaluation of transmission-blocking vaccines

    The Spin-Statistics Connection in Quantum Gravity

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    It is well-known that is spite of sharing some properties with conventional particles, topological geons in general violate the spin-statistics theorem. On the other hand, it is generally believed that in quantum gravity theories allowing for topology change, using pair creation and annihilation of geons, one should be able to recover this theorem. In this paper, we take an alternative route, and use an algebraic formalism developed in previous work. We give a description of topological geons where an algebra of "observables" is identified and quantized. Different irreducible representations of this algebra correspond to different kinds of geons, and are labeled by a non-abelian "charge" and "magnetic flux". We then find that the usual spin-statistics theorem is indeed violated, but a new spin-statistics relation arises, when we assume that the fluxes are superselected. This assumption can be proved if all observables are local, as is generally the case in physical theories. Finally, we also show how our approach fits into conventional formulations of quantum gravity.Comment: LaTeX file, 31 pages, 5 figure

    Critical behavior of the planar magnet model in three dimensions

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    We use a hybrid Monte Carlo algorithm in which a single-cluster update is combined with the over-relaxation and Metropolis spin re-orientation algorithm. Periodic boundary conditions were applied in all directions. We have calculated the fourth-order cumulant in finite size lattices using the single-histogram re-weighting method. Using finite-size scaling theory, we obtained the critical temperature which is very different from that of the usual XY model. At the critical temperature, we calculated the susceptibility and the magnetization on lattices of size up to 42342^3. Using finite-size scaling theory we accurately determine the critical exponents of the model and find that ν\nu=0.670(7), γ/ν\gamma/\nu=1.9696(37), and β/ν\beta/\nu=0.515(2). Thus, we conclude that the model belongs to the same universality class with the XY model, as expected.Comment: 11 pages, 5 figure

    Universal renormalization-group dynamics at the onset of chaos in logistic maps and nonextensive statistical mechanics

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    We uncover the dynamics at the chaos threshold μ\mu_{\infty} of the logistic map and find it consists of trajectories made of intertwined power laws that reproduce the entire period-doubling cascade that occurs for μ<μ\mu <\mu_{\infty}. We corroborate this structure analytically via the Feigenbaum renormalization group (RG) transformation and find that the sensitivity to initial conditions has precisely the form of a qq-exponential, of which we determine the qq-index and the qq-generalized Lyapunov coefficient λq\lambda _{q}. Our results are an unequivocal validation of the applicability of the non-extensive generalization of Boltzmann-Gibbs (BG) statistical mechanics to critical points of nonlinear maps.Comment: Revtex, 3 figures. Updated references and some general presentation improvements. To appear published as a Rapid communication of PR

    The relationship between internalizing and externalizing problems in adolescence: does gender make a difference?

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    Desenvolvimento de recursos didácticos informatizados no âmbito da educação para o desenvolvimento sustentável. o exemplo do courseware SeRe

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    A falta de recursos didácticos informatizados de qualidade para o 1º e 2º Ciclos do Ensino Básico (1º/2º CEB), concebidos no âmbito da Educação para o Desenvolvimento Sustentável (EDS), numa perspectiva de Ensino por Pesquisa, determinou a organização de uma equipa multidisciplinar para o desenvolvimento do «Courseware Sere - O Ser Humano e os Recursos Naturais». Ajustando alguns princípios de desenvolvimento de software, particularmente de Design Centrado no Utilizador (DCU), o trabalho da equipa multidisciplinar, constituída por elementos com diversas competências (ao nível da Didáctica das Ciências, da Tecnologia Educativa, de Design e de Programação), centrou-se no desenvolvimento de um recurso didáctico informatizado que integra várias tipologias de software, nomeadamente simulações e visualizações, com as actividades didácticas. A orientação do recurso, as temáticas propostas e as metodologias e estratégias de exploração privilegiadas fundamentam-se: i) na identificação das orientações nacionais e internacionais da EDS; ii) na identificação das necessidades e interesses dos professores quanto à implementação de actividades com orientação EDS (Sá, 2008; Sá e Martins, 2007), iii) no paradigma de ensino por competências (Cachapuz, Sá-Chaves e Paixão, 2004) e iv) no recurso a um design interactivo centrado no utilizador (Costa, Loureiro, Reis, Sá, Guerra e Vieira, 2009; Guerra, 2007). Neste artigo faz-se uma apresentação do processo de desenvolvimento do recurso didáctico, das temáticas propostas e das metodologias e estratégias de exploração perspectivadas pelos autores do recurs

    Geochemistry, mineralogy, solid-phase fractionation and oral bioaccessibility of lead in urban soils of Lisbon

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    An urban survey of Lisbon, the largest city in Portugal, was carried out to investigate its environmental burden, emphasizing metallic elements and their public health impacts. This paper examines the geochemistry of lead (Pb) and its influence on human health data. A total of 51 soil samples were collected from urban recreational areas used by children to play outdoors. The semi-quantitative analysis of Pb was carried out by inductively coupled plasma mass spectrometry after an acid digestion. X-ray diffraction was used to characterize the soil mineralogy. The solid-phase distribution of Pb in the urban soils was investigated on a subset of 7 soils, out of a total of 51 samples, using a non-specific sequential extraction method coupled with chemometric analysis. Oral bioaccessibility measurements were obtained using the Unified BARGE Method developed by the Bioaccessibility Research Group of Europe. The objectives of the study are as follows: (1) investigation of Pb solid-phase distribution; (2) interpretation of Pb oral bioaccessibility measurements; (3) integration of metal geochemistry with human health data; and (4) understanding the influence of geochemistry and mineralogy on oral bioaccessibility. The results show that the bioaccessible fraction of Pb is lower when major metal fractions are associated with less soluble soil phases such as Fe oxyhydroxides, and more increased when the metal is in the highly soluble carbonate phase. However, there is some evidence that the proportion of carbonates in the soil environment is also a key control over the oral bioaccessibility of Pb, irrespective of its solid-phase fractionation

    An AAL collaborative system: the AAL4ALL and a mobile assistant case study

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    "15th IFIP WG 5.5 Working Conference on Virtual Enterprises, PRO-VE 2014, Amsterdam, The Netherlands, October 6-8, 2014"The areas of Ambient Assisted Living (AAL) and Intelligent Systems (IS) are in full development, but there are still some issues to be resolved. One issue is the myriad of user oriented solutions that are rarely built to interact or integrate with other systems available in the market. In this paper we present the AAL4ALL project and the UserAccess implementation, showing a novel approach towards virtual organizations, interoperability and certification. The aim of this project is to provide a collaborative network of services and devices that connect every user and product from other developers, building a heterogeneous ecosystem. Thus establishing an environment for collaborative care systems, which may be available to the users in from of safety services, comfort services and healthcare services.Project "AAL4ALL", co-financed by the European Community Fund FEDER, through COMPETE - Programa Operacional Factores de Competitividade (POFC). Foundation for Science and Technology (FCT), Lisbon, Portugal, through Project PEst-C/CTM/LA0025/2013 and the project PEst-OE/EEI/UI0752/2014. Project CAMCoF - Context-aware Multimodal Communication Framework fund-ed by ERDF -European Regional Development Fund through the COMPETE Pro-gramme (operational programme for competitiveness) and by National Funds through the FCT - Fundação para a Ciência e a Tecnologia (Portuguese Foundation for Science and Technology) within project FCOMP-01-0124-FEDER-028980
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