594 research outputs found

    La literatura como ideología y la crítica literaria

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    Dada a importância que os comportamentos suicidários assumem nos adolescentes, torna-se pertinente a análise dos sentidos associados ao suicídio no campo particular da sua construção social. Várias investigações evidenciam que, o modo como as pessoas constróem explicações para os acontecimentos, não só se baseia nas crenças e experiências dos seus grupos de pertença, como determina comportamentos. Neste primeiro artigo, integrado numa investigação mais ampla sobre as representações sociais do suicídio em adolescentes, analisa-se o tipo de explicações queos jovens dão para este fenómeno, em função do sexo, idade, ano de escolaridade, região e ideação suicida.Participaram no estudo 822 adolescentes, entre os 15 e os 23 anos, estudantes dos 10.º, 11.º e 12.º anos de escolas secundárias de Évora, Guimarães, Lisboa e Santarém. Os resultados sugerem que estamos perante uma representação hegemónica das explicações do suicídio. Esta varia com o sexo, a idade e o ano de escolaridade, assim como com a região onde os jovens estudam e, também, com o facto de terem tido ou não ideação suicida. Tendo em conta a necessidade de responder adequadamente a tal diversidade, estes resultados assumem particular relevância no planeamento de estratégias preventivas

    Regional variation in coronary heart disease mortality trends in Portugal, 1981-2012

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    BACKGROUND: Information is scarce about the geographic variation in time trends of mortality from coronary heart disease (CHD). We aimed to describe trends in death rates, absolute number of deaths and years of life lost (YLL) due to CHD among men and women in Portugal, by region, from 1981 to 2012. METHODS: The age-standardized mortality rates from CHD were estimated by sex and region. We used joinpoint regression analysis to calculate the annual percent change (APC) in mortality and to identify points of significant change in the trend. The YLL due to premature mortality for CHD were computed using the Global Burden of Disease method. RESULTS: The age-adjusted mortality from CHD decreased between 1981 and 2012, both in men and women, but with significantly different APC by region. Smaller declines in rates were observed in Alentejo (men: APC 1993-2012: -2.4%; women: APC 1991-2012: -2.4%). The greatest decline was observed in Madeira between 2003 and 2012, in men (APC: -7.6%) and women (APC: -9.7%). The decline in rates in Algarve started only after 2003, whereas it was consistent from 1981 in the North and started in the 1990s in most other regions. A decrease in the number of deaths was only observed after 2000. The YLL from CHD decreased from 1981 to 2012, mainly after 2000. CONCLUSIONS: In Portugal, between 1981 and 2012, relative declines of CHD mortality indicators were different by geographic region. Consistent decreases in mortality rates were only observed in the Centre, Lisbon and North, the most populated and urbanized regions

    Avaliação da resistência ao cisalhamento da união entre duas ligas a base de CoCr e uma cerâmica

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    INTRODUCTION: Based on the importance of the integrity of the metal/ceramic interface, the purpose of this work was to evaluate the shear bond strength of the metal-ceramic union of two Co-Cr alloys (Wirobond C, Bego; Remanium 2000, Dentaurum) combined with Omega 900 ceramic (Vita Zahnfabrik). MATERIAL and METHOD: Eleven cylindrical matrixes were made for each alloy, and the metallic portion was obtained with the lost wax casting technique with standardized waxing of 4mm of height and of 4mm of diameter. The ceramic was applied according to the manufacturer’s recommendations with the aid of a teflon matrix that allowed its dimension to be standardized in the same size as the metallic portion. The specimens were submitted to the shear bond test in an universal testing machine (EMIC), with the aid of a device developed for such intention, and constant speed of 0.5mm/min. RESULTS and CONCLUSIONS: The mean resistance was 48.387MPa for Wirobond C alloy, with standard deviation of 17.718, and 55.956MPa for Remanium 2000, with standard deviation of 17.198. No statistically significant difference was observed between the shear strength of the two metal-ceramic alloys. ______________________________________________________________________________________________________________ RESUMOINTRODUÇÃO: Baseados na importância da integridade da interface metal-cerâmica, este trabalho tem como objetivo avaliar a resistência ao cisalhamento da união metal-cerâmica de duas ligas de Co-Cr (Wirobond C, Bego; Remanium 2000, Dentaurum) combinadas com a cerâmica Omega 900 (Vita Zahnfabrik). MATERIAIS E MÉTODOS: Foram confeccionados 11 corpos-de-prova cilíndricos para cada liga utilizada, sendo que a porção metálica foi obtida por fundição pela técnica da cera perdida, através de enceramentos padronizados com 4mm de altura por 4mm de diâmetro. A aplicação da cerâmica foi realizada segundo recomendações do fabricante, com auxílio de uma matriz de teflon que permitia sua padronização com as mesmas dimensões da porção metálica. Os corpos-de-prova foram submetidos ao ensaio de resistência ao cisalhamento em máquina de ensaios universal (EMIC), com auxílio de dispositivo desenvolvido para tal propósito, sob velocidade constante de 0,5mm/ min. RESULTADOS E CONCLUSÕES: As médias de resistência obtidas foram 48,387 MPa para a liga Wirobond C, com desvio padrão de 17,718, e 55,956 MPa para a Remanium 2000, com desvio padrão de 17,198. Após análise de variância foi possível observar que não há diferença estatisticamente significante entre os valores de resistência ao cisalhamento das duas ligas metalocerâmicas

    Raw clays from Morocco for degradation of pollutants by Fenton-like reaction for water treatment

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    Three raw clays from Morocco were used as heterogeneous catalysts for Fenton-like oxidation of organic pol-lutants in water. The selected pollutants were two dyes used in the textile industry, Congo Red (CR) and Tar-trazine (Tar, known also as a food coloring compound, E102) and Caffeine (Caf), a stimulant drug present in popular beverages such as coffee and tea, commonly used in Morocco. Two different processes were used for their degradation: (i) Fenton-like reaction; and (ii) electro-Fenton-like reaction. Process (i) was used for Tar and Caf degradation in the presence of clays from different region of Morocco (Middle Atlas -ClayMA, Fez -ClayF, and Ourika -ClayO), the best results being obtained with ClayO and ClayMA, on which 60.0% and 23.4% of conversion and 41.0% and 20.5% of mineralization were achieved for Tar and Caf, respectively. Process (ii) was used for degrading CR by clay-modified electrodes (CME) using the rawclays from Fez and Ourika regions (ClayF and ClayO). The stability of the CME was assessed by cyclic voltammetry studies, which proved that they are stable in the experimental conditions used. The electrodegradation of CR dye, performed without hydrogen peroxide in the reaction medium, achieve 67.0% of mineralization at the end of electrolysis (2 h)

    Drought generates large, long-term changes in tree and liana regeneration in a monodominant Amazon forest

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    The long-term dynamics of regeneration in tropical forests dominated by single tree species remains largely undocumented, yet is key to understanding the mechanisms by which one species can gain dominance and resist environmental change. We report here on the long-term regeneration dynamics in a monodominant stand of Brosimum rubescens Taub. (Moraceae) at the southern border of the Amazon forest. Here the climate has warmed and dried since the mid-1990′s. Twenty-one years of tree and liana regeneration were evaluated in four censuses in 30 plots by assessing species abundance, dominance, and diversity in all regeneration classes up to 5 cm diameter. The density of B. rubescens seedlings declined markedly, from 85% in 1997 to 29% in 2018 after the most intense El Niño-driven drought. While the fraction contributed by other tree species changed little, the relative density of liana seedlings increased from just 1 to 54% and three-quarters of liana species underwent a ten-fold or greater increase in abundance. The regeneration community experienced a high rate of species turnover, with changes in the overall richness and species diversity determined principally by lianas, not trees. Long-term maintenance of monodominance in this tropical forest is threatened by a sharp decline in the regeneration of the monodominant species and the increase in liana density, suggesting that monodominance will prove to be a transitory condition. The close association of these rapid changes with drying indicates that monodominant B. rubescens forests are impacted by drought-driven changes in regeneration, and therefore are particularly sensitive to climatic change

    TRY plant trait database - enhanced coverage and open access

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    Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

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    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

    Alamedas, paseos y carruajes: función y significación social en España y América (siglos XVI-XIX)

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    An analysis of boulevards and promenades linked to horse-drawn carriages in Spain and the Americas. Carriages have rarely been studied as a means of interpreting the evolution of cities. Nevertheless, to understand these urban aspects it is essential to relate them, to places such as Seville, Madrid, Mexico, Lima or others towns on both shores of the Atlantic Ocean.Análisis en España y América de las alamedas y los paseos vinculados a los coches de caballos. Estos apenas han sido tenidos en cuenta al interpretar la evolución de las ciudades, no obstante, para comprender dichas tipologías urbanas es imprescindible relacionarlas con los carruajes, como haremos con casos emblemáticos como los de Sevilla, Madrid, México, Lima u otras ciudades a ambos lados del Atlántico
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