5,405 research outputs found

    Adolescent's physical activity : perspectives for active lifestyles of a school population in Oeiras

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    FCT (Fundação para a Ciência e a Tecnologia), IDP (Instituto do Desporto de Portugal), AIESEP World Congres

    The Effects of Emotional Working Memory Training on Trait Anxiety

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    Background: Trait anxiety is a pervasive tendency to attend to and experience fears and worries to a disproportionate degree, across various situations. Decreased vulnerability to trait anxiety has been linked to having higher working memory capacity and better emotion regulation; however, the relationship between these factors has not been well-established. Objective: This study sought to determine if participants who undergo emotional working memory training will have significantly lower trait anxiety post-training. The study also sought to determine if emotion regulation mediated the relationship between working memory training and trait anxiety. Method: An experimental group comprising of 49 participants underwent 20 days of computerized emotional working memory training, which involved viewing a continuous stream of emotionally-charged content on a grid, and then remembering the location and color of items presented on the grid. The control group comprised of 51 participants. Results: Participants of the experimental group had significantly lower trait anxiety compared to controls, post-training. Subsequent mediation analysis determined that working memory training capacity gains were significantly related to anxiety reduction as measured by form Y2 of the Spielberger State-Trait Anxiety Inventory (STAI-Y2). Emotion regulation, as measured by the Emotional Regulation Questionnaire (ERQ), was found not to mediate between working memory capacity gains and trait anxiety reduction. Conclusion: Working memory capacity gains and reductions in levels of trait anxiety were observed following emotional working memory training. The study may therefore be useful in informing interventions targeted at improving working memory capacity, and reducing levels of trait anxiety. Moreover, it proposes for future research to further look into the mediating role of emotion regulation via the development or utilization of more comprehensive measures of emotion regulation

    Efeitos do alumínio em pimenteiras do reino (piper nigrum, L.) cultivadas em solução nutritiva.

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    A pimenteira do reino (Piper nigrum, L.) vem sendo cultivada, em sua maior parte, em áreas com solos de baixa fertilidade natural, caracterizadas por baixa saturação por bases, alta saturação de alumínio e acidez elevada. Visando estudar os efeitos do alumínio sobre a cultura foi conduzido um experimento com a cultivar Guajarina em solução nutritiva. As doses de alumínio estudadas foram: 0; 5; 10; 15; 20 e 40mg/L. O sintoma inicial de toxidez de alumínio foi caracterizado por um retardamento no crescimento radicular, com aumento no diâmetro das raízes. Observou-se efeito positivo do alumínio na produção de matéria seca com adição de até 15mg/L na solução, o que correspondeu a maior absorção de P, K, Ca, Mg, Mn, Fe e AL Conclui-se que a pimenteira é tolerante à presença de concentrações de Al inferiores a 20mg/L no substrato. Doses superiores provocam distúrbios nutricionais com redução no crescimento da plant

    Influência do manganês sobre a nutrição mineral e crescimento da pimenteira do reino (Piper nigrum, L.).

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    A pimenteira do reino (Piper nigrum, L.) vem sendo cultivada em sua maior parte em solos com acidez elevada e balia saturação por bases. O manganês em condições de alta acidez pode provocar toxidez às plantas. Visando estudar os efeitos do manganês nessa cultura foi conduzido um experimento com a cultivar Guajarina em solução nutritiva, O manganês foi fornecido nas concentrações de 0; 10; 20; 30; 40 e 50 mg/L. Na ausência do elemento foram observados sintomas de deficiência e redução no crescimento. O excesso de manganês (30 mg/L) na solução nutritiva reduziu o desenvolvimento das plantas e a absorção de P, K, Ca, Mg, Cu, Fe e ZN. Observaram-se sintomas de toxidez de manganês a partir da concentração de 20 mg/L, caracterizados por cloróse e pontos necróticos nas folhas

    Electronic tongue: a versatile tool for mineral and fruit-flavored waters recognition

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    Natural mineral waters (still), effervescent natural mineral waters (sparkling) and aromatized waters with fruit-flavors (still or sparkling) are an emerging market. In this work, the capability of a potentiometric electronic tongue, comprised with lipid polymeric membranes, to quantitatively estimate routinely quality physicochemical parameters (pH and conductivity) as well as to qualitatively classify water samples according to the type of water was evaluated. The study showed that a linear discriminant model, based on 21 sensors selected by the simulated annealing algorithm, could correctly classify 100 % of the water samples (leave-one out cross-validation). This potential was further demonstrated by applying a repeated K-fold cross-validation (guaranteeing that at least 15 % of independent samples were only used for internal-validation) for which 96 % of correct classifications were attained. The satisfactory recognition performance of the E-tongue could be attributed to the pH, conductivity, sugars and organic acids contents of the studied waters, which turned out in significant differences of sweetness perception indexes and total acid flavor. Moreover, the E-tongue combined with multivariate linear regression models, based on sub-sets of sensors selected by the simulated annealing algorithm, could accurately estimate waters pH (25 sensors: R 2 equal to 0.99 and 0.97 for leave-one-out or repeated K-folds cross-validation) and conductivity (23 sensors: R 2 equal to 0.997 and 0.99 for leave-one-out or repeated K-folds cross-validation). So, the overall satisfactory results achieved, allow envisaging a potential future application of electronic tongue devices for bottled water analysis and classification.This study was supported by Fundação para a Ciência e Tecnologia (FCT) and the European Community fund FEDER, under the Program PT2020 (Project UID/EQU/50020/2013) and under the strategic funding of UID/BIO/04469/2013 unit

    Shape anisotropic iron oxide-based magnetic nanoparticles: synthesis and biomedical applications

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    Research on iron oxide-based magnetic nanoparticles and their clinical use has been, so far, mainly focused on the spherical shape. However, efforts have been made to develop synthetic routes that produce different anisotropic shapes not only in magnetite nanoparticles, but also in other ferrites, as their magnetic behavior and biological activity can be improved by controlling the shape. Ferrite nanoparticles show several properties that arise from finite-size and surface effects, like high magnetization and superparamagnetism, which make them interesting for use in nanomedicine. Herein, we show recent developments on the synthesis of anisotropic ferrite nanoparticles and the importance of shape-dependent properties for biomedical applications, such as magnetic drug delivery, magnetic hyperthermia and magnetic resonance imaging. A brief discussion on toxicity of iron oxide nanoparticles is also included.This research was funded by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding of CF-UM-UP (UID/FIS/04650/2019) and through the research project PTDC/QUI–QFI/28020/2017 (POCI-01–0145-FEDER-028020), financed by European Fund of Regional Development (FEDER), COMPETE2020 and Portugal2020. The APC was also funded by FCT. S.R.S. Veloso acknowledges FCT for a PhD grant (SFRH/BD/144017/2019)

    Potencial de Eucalyptus grandis e Eucalyptus cloeziana para fitoextração de arsênio

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    Este trabalho teve como objetivo avaliar o potencial de mudas de Eucalyptus grandis Hill ex Maiden, Eucalyptus cloeziana F. Muell, para fitorremediação de solos contaminados por arsênio. Amostras de solo foram incubadas por período de 15 dias com doses crescentes de arsênio (0, 50, 100, 200 e 400 mg dm-3 de As disponível), como fonte utilizou-se o arsenato de sódio (Na2HAsO4). O ensaio foi conduzido por um período de 90 dias após o transplantio. Após 30 dias de exposição o E. cloeziana exibiu pontuações arroxeadas nas folhas basais com clorose internerval seguida de necrose e morte da gema apical na dose de 400 mg dm-3. As doses crescentes de arsênio no solo reduziram significativamente a produção de matéria seca de raízes e parte aérea, altura e diâmetro de planta das ambas às espécies, sendo mais acentuada nas plantas de E. cloeziana. Para as espécies, os maiores teores de As foram observados no sistema radicular, com maiores valores para E. cloeziana (305,72 mg kg-1) na dose de 400 mg dm-3, sendo que o maior acúmulo de As foi observado nas plantas E. grandis, que demonstrou ser uma espécie com potencial para fitoextração de arsênio, com tendências de acumulação no sistema radicular e no caule
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