556 research outputs found

    Differential item functioning due to gender between depression and anxiety items among Chilean adolescents

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    Although much is known about the higher prevalence of anxiety and depressive disorders among adolescent females, less is known about the differential item endorsement due to gender in items of commonly scales used to measure anxiety and depression. We conducted a study to examine if adolescent males and females from Chile differed on how they endorsed the items of the Youth Self-Report (YSR) anxious/depressed problem scale. We used data from a cross-sectional sample consisting of 925 participants (Mean age = 14, SD=1.3, 49% females) of low to lower-middle socioeconomic status. A two-parameter logistic (2PL) IRT DIF model was fit. Results revealed differential item endorsement (DIF) by gender for six of the 13 items with adolescent females being more likely to endorse a depression item while males were found more likely to endorse anxiety items. Findings suggest that items found in commonly utilized measures of anxiety and depression symptoms may not equally capture true levels of these behavioral problems among adolescent males and females. Given the high levels of mental disorders in Chile and surrounding countries, further attention should be focused on increasing the number of empirical studies examining potential gender differences in the assessment of mental health problems among Latin American populations to better aid our understanding of the phenomenology and determinants of these problems in the region.R01 HD033487 - NICHD NIH HHS; R01 DA021181-05 - NIDA NIH HHS; R01 DA021181 - NIDA NIH HH

    Late Holocene evolution of the Lower Tagus alluvial plain and heavy metals content: preliminary results

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    This paper aims to contribute to the fluvial dynamic knowledge of the Lower Tagus during the late Holocene. Two cores were done in selected geomorphological positions at the alluvial plain. Each ten centimeters of sediments were submitted to sedimentological and geochemical analyses in order to identify human contamination by heavy metals, sedimentation rates and environmental changes in the main channel position. The main conclusions are: (1) The witness of the lateral migration of the fluvial channel; (2) The very irregular sedimentation rate, from 3mm per year to 0.1mm per year; (3) The diversified contamination of fluvial sediments and fluvial channels by heavy metals, namely Cu due to cooper sulphate vineyards and Pb due to petrol and Cr from the tanning industries.Este trabajo pretende contribuir al conocimiento de la dinámica fluvial del curso inferior del río Tajo durante el Holoceno final. Se han realizado dos sondeos en lugares seleccionados de la llanura aluvial. Muestras del sedimento obtenidas cada diez centímetros se han analizado con el fin de identificar la contaminación humana con metales pesados, las tasas de sedimentación y posibles cambios en la posición del cauce principal. Las conclusiones más importantes son: (1) La prueba de la existencia de migración lateral del cauce fluvial; (2) La gran irregularidad de la tasa de sedimentación, que varia entre 0,1 y 3mm por año; (3) La variada contaminación de los sedimentos fluviales y de los cauces por metales pesados, especialmente Cu debido a la aplicación de sulfato de cobre en viñedos, Pb debido al petróleo y Cr por las industrias de curtidos.info:eu-repo/semantics/publishedVersio

    tackling malaria

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    Malaria is an infectious disease that affects over 216 million people worldwide, killing over 445,000 patients annually. Due to the constant emergence of parasitic resistance to the current antimalarial drugs, the discovery of new drug candidates is a major global health priority. Aiming to make the drug discovery processes faster and less expensive, we developed binary and continuous Quantitative Structure-Activity Relationships (QSAR) models implementing deep learning for predicting antiplasmodial activity and cytotoxicity of untested compounds. Then, we applied the best models for a virtual screening of a large database of chemical compounds. The top computational predictions were evaluated experimentally against asexual blood stages of both sensitive and multi-drug-resistant Plasmodium falciparum strains. Among them, two compounds, LabMol-149 and LabMol-152, showed potent antiplasmodial activity at low nanomolar concentrations (EC50 <500 nM) and low cytotoxicity in mammalian cells. Therefore, the computational approach employing deep learning developed here allowed us to discover two new families of potential next generation antimalarial agents, which are in compliance with the guidelines and criteria for antimalarial target candidates.publishersversionpublishe

    The performance of concrete exposed to marine environments: predictive modelling and use of laboratory/on site test method

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    This paper reports an approach by which laboratory based testing and numerical modelling can be combined to predict the long term performance of a range of concretes exposed to marine environments. Firstly, a critical review of the test methods for assessing the chloride penetration resistance of concrete is given. The repeatability of the different test results is also included. In addition to the test methods, a numerical simulation model is used to explore the test data further to obtain long-term chloride ingress trends. The combined use of testing and modelling is validated with the help of long-term chloride ingress data from a North Sea exposure site. In summary, the paper outlines a methodology for determining the long term performance of concrete in marine environments

    Effect of temperature on behavior, glycogen content, and mortality in Limnoperna fortunei (Dunker, 1857) (Bivalvia: Mytilidae)

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    Limnoperna fortunei (Dunker 1857) is a freshwater mussel with physiological tolerance to different environmental conditions, which may explain its success as an invasive species. The role of abiotic factors in its establishment, abundance and projections of risk of further spread into several areas has been studied. These mussels may respond to multiple environmental stressors, such as temperature, through physiological mechanisms, behavioral responses, mortality or some combination of these. The aim of this study was to investigate the behavioral responses (valve closing), glycogen concentrations and mortality of L. fortunei under four different temperatures (5°C, 10°C, 20°C and 30° C) during a chronic test (30 days). Two-way analysis of variance (ANOVA) was used to compare glycogen concentrations across days of the experiment and at the different temperatures. Differences in valve-closing behavior and mortality among temperatures were tested using repeated-measures ANOVA. We observed that most of the mussels maintained at 5°C closed their valves (74.7 ± 15.3%), indicating that they remain inactive at low temperatures. The glycogen levels significantly differed among the temperatures tested. These differences occurred mainly due to the high glycogen values observed in mussels exposed to 10°C. Stability in glycogen concentrations was observed within each particular temperature. The cumulative mortality was higher at extreme temperatures (5°C and 30°C). The ideal temperature for laboratory maintenance and tests is approximately 20°C. Our data also show that L. fortunei can survive and maintain their energy reserves (glycogen) for several days at 5°C, an important feature related to its invasion success

    Chloride ingress into marine exposed concrete: A comparison of empirical- and physically- based models

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    In establishing the reliability of performance-related design methods for concrete – which are relevant for resistance against chloride-induced corrosion - long-term experience of local materials and practices and detailed knowledge of the ambient and local micro-climate are critical. Furthermore, in the development of analytical models for performance-based design, calibration against test data representative of actual conditions in practice is required. To this end, the current study presents results from full-scale, concrete pier-stems under long-term exposure to a marine environment with work focussing on XS2 (below mid-tide level) in which the concrete is regarded as fully saturated and XS3 (tidal, splash and spray) in which the concrete is in an unsaturated condition. These exposures represent zones where concrete structures are most susceptible to ionic ingress and deterioration. Chloride profiles and chloride transport behaviour are studied using both an empirical model (erfc function) and a physical model (ClinConc). The time dependency of surface chloride concentration (Cs) and apparent diffusivity (Da) were established for the empirical model whereas, in the ClinConc model (originally based on saturated concrete), two new environmental factors were introduced for the XS3 environmental exposure zone. Although the XS3 is considered as one environmental exposure zone according to BS EN 206-1:2013, the work has highlighted that even within this zone, significant changes in chloride ingress are evident. This study aims to update the parameters of both models for predicting the long term transport behaviour of concrete subjected to environmental exposure classes XS2 and XS3
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