1,680 research outputs found

    Primary Systemic Vasculitis in Childhood

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    As vasculites sistémicas constituem um grupo de doenças, pouco frequentes na infância, caracterizadas por inflamação e necrose vascular. A sua tradução clínica é heterogénea, condicionada pelo tipo de vaso e orgão afectados. Recentemente foi proposta uma classificação das vasculites em idade pediátrica, que tem em conta a dimensão dos vasos envolvidos, sendo também validados critérios de diagnóstico para os tipos mais frequentes em crianças. A presente revisão tem como objectivo abordar os tipos mais frequentes de vasculites na infância, suas manifestações clínicas, diagnóstico e terapêutica

    Children’s participation in early childhood education: a theoretical overview

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    Children’s right to participate in all matters and decisions affecting them has gained recognition in society. Its promotion is recommended from an early age – namely, in early childhood education settings – and it is described as benefiting children, adults and the community in general. Given the complex and polysemic meaning of participation, different conceptualizations, models and perspectives have emerged. In this article, the authors provide a theoretical overview, describing relevant models, concepts and contributions from distinct perspectives and fields of knowledge – sociological, educational, developmental and sociocultural – as well as contributions from social policy. This overview is particularly relevant to inform research and practice about children’s participation in early childhood education.info:eu-repo/semantics/acceptedVersio

    Transformer Oil Passivation and Impact of Corrosive Sulphur

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    In recent years a significant volume of research has been undertaken in order to understand the recent failures in oil insulated power apparatus due to deposition of copper sulphide on the conductors and in the insulation paper. Dibenzyl Disulfide (DBDS) has been found to be the leading corrosive sulphur compound in the insulation oil [1]. The process of copper sulphide formation and the deposition in the paper is still being investigated, but a recently proposed method seems to be gaining some confidence [1]. This method suggests a two-step process; initially the DBDS and some oil soluble copper complexes are formed. Secondly the copper complexes are absorbed in the paper insulation, where they then decompose into copper sulphide [2]. The most commonly used mitigating technique for corrosive sulphur contaminated oil is passivation, normally using Irgamet 39 or 1, 2, 3-benzotriazole (BTA). The passivator is diluted into the oil to a concentration of around 100ppm, where it then reacts with the copper conductors to form a complex layer around the copper, preventing it from interacting with DBDS compounds and forming copper sulphide. This research project will investigate the electrical properties of HV transformers which have tested positive for corrosive sulphur, and the evolution of those properties as the asset degrades due to sulphur corrosion. Parallel to this the long term properties of transformers with passivated insulation oil will be analysed in order to understand the passivator stability and whether it is necessary to keep adding the passivator to sustain its performance. Condition monitoring techniques under investigation will include dielectric spectroscopy, frequency response analysis, recovery voltage method (aka interfacial polarisation) amongst others. Partial discharge techniques will not be investigated, as the voltage between the coil plates is low and therefore it will not contribute significantly to the overall insulation breakdown, in corrosive oil related faults [3]. The goal of this research is to establish key electrical properties in both passivated and non-passivated power transformers that demonstrate detectable changes as the equipment degrades due to the insulation oil being corrosive

    Relationship of force metrics with swimming performance in age-group swimmers

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    Children's right to participate in early childhood education settings: a systematic review

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    Children's right to participate is considered pivotal for establishing a culture of democracy and citizenship. Although this is not a new concept, its application remains a challenge. This review aims to map peer-reviewed empirical research conducted on children's right to participate, in center-based early childhood education settings, from 1980 on. A systematic literature search was performed and 36 studies met the inclusion criteria. Findings suggest a limited number of publications, conducted mostly in northern Europe countries, in the education field. Regarding definitions and theoretical backgrounds, sociological, legal, democratic, and educational discourses converge. There is a prominence of qualitative studies, a greater focus of research on ideas about participation, and, to a lesser extent, a focus on practices to promote participation. There is more emphasis on teacher's perspectives and practices, with few studies relying on children as informants, and limited sound measures to assess children's participation. Future research should rely on multiple informants, and investigate associations between this right and children's individual outcomes.info:eu-repo/semantics/acceptedVersio

    Serum antibodies to Vibrio vulnificus biotype 3 lipopolysaccharide and susceptibility to disease caused by the homologous V. vulnificus biotype

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    In 1996 an outbreak of severe soft tissue infections caused by Vibrio vulnificus unexpectedly erupted in fish consumers in Israel with relatively little morbidity in fish farmers. To test the hypothesis that recurrent exposure of fishermen to the virulent strain may have provided protection against severe or symptomatic disease, we investigated the association between the immune response to V. vulnificus biotype 3 lipopolysaccharide (BT3 LPS) and disease susceptibility in fish farmers and fish consumers. Serum samples were tested for IgA and IgG of anti-BT3 LPS in fishermen and fish consumers who suffered from V. vulnificus BT3 infections and their matched controls. Pre-existing levels of IgG (IgG0) of anti-BT3 LPS were significantly lower in diseased fishermen who developed disease associated with the homologous biotype, compared to controls. In multivariate analysis, levels of IgG0 anti-BT3 LPS remained the only variable significantly associated with disease occurrence in fishermen. Higher levels of pre-existing IgG anti-BT 3 LPS antibodies may be associated with protection against severe or symptomatic disease with the homologous biotype in fishermen but not in subjects from the general public

    Source identity shapes spatial preference in primary auditory cortex during active navigation

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    Information about the position of sensory objects and identifying their concurrent behavioral relevance is vital to navigate the environment. In the auditory system, spatial information is computed in the brain based on the position of the sound source relative to the observer and thus assumed to be egocentric throughout the auditory pathway. This assumption is largely based on studies conducted in either anesthetized or head-fixed and passively listening animals, thus lacking self-motion and selective listening. Yet these factors are fundamental components of natural sensing1 that may crucially impact the nature of spatial coding and sensory object representation.2 How individual objects are neuronally represented during unrestricted self-motion and active sensing remains mostly unexplored. Here, we trained gerbils on a behavioral foraging paradigm that required localization and identification of sound sources during free navigation. Chronic tetrode recordings in primary auditory cortex during task performance revealed previously unreported sensory object representations. Strikingly, the egocentric angle preference of the majority of spatially sensitive neurons changed significantly depending on the task-specific identity (outcome association) of the sound source. Spatial tuning also exhibited large temporal complexity. Moreover, we encountered egocentrically untuned neurons whose response magnitude differed between source identities. Using a neural network decoder, we show that, together, these neuronal response ensembles provide spatiotemporally co-existent information about both the egocentric location and the identity of individual sensory objects during self-motion, revealing a novel cortical computation principle for naturalistic sensing

    Contribuição para a análise tectono-sedimentar do Fosso de Aljezur (SW de Portugal)

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    The Aljezur "graben" is a crucial piece in understanding the Caenozoic evolution of the SW atlantic portuguese edge. Detailed study of the sedimentary filling and bordering accidents allows the identification of several evolution steps since the Miocene. The graben is bordered by accidents that dislocate geomorphologic surfaces (Littoral Platform to the W, Interior Platform to the E), and also Neogene sedimentary units. The sedimentary filling is composed by conglomerates and sands grading into clays and bioclastic limestones (Burdigalian to Serravalian), upon which lie unconformably fine reddish sands, sometimes with abundant micas. Genetic and geometric relationships between these sands, those in higher surfaces outside the "graben" and the main bordering faults, are discussed. As a conclusion, the reconstruction of the tectono-sedimentary evolution is attempted, integrating it in a "pull-apart" context associated with the Messejana-fault system and it's reactivation by the differently orientated alpine compressions

    Effects of alkaline and acid solutions on glass/epoxy composites

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    Composite structures can be exposed to a range of corrosive environments during their in-service life, which causes degradation in terms of material properties. The effect of alkaline and acid solutions on the GRP mechanical properties can be found in open literature, but the studies presented are not sufficient to establish a full knowledge of this subject. In this paper the flexural properties and the impact strength of a glass fibre/epoxy composite after immersion in hydrochloric acid (HCl) and sodium hydroxide (NaOH) were analysed. Independently of the solution, the flexural strength and the flexural modulus decrease with the exposure time. However, alkaline solution promotes higher decrease of the flexural properties than the acid solution. The same tendency was observed for impact strength
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