2,228 research outputs found

    Surveys as cultural artefacts : applying the international self-report delinquency study to Latin American adolescents

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    Survey instruments are often watermarked with the language, thought patterns, experience and expectations of their designers’ cultural world. This creates some evident challenges when using surveys in international research projects (for example, in finding equivalent terms in translation), but also some less evident ones deriving from potentially hidden local variations in social experience, values and cognition. Using examples from the International Self-Report Delinquency Study, this article identifies several potential challenges to measurement that arise when an instrument designed with the youth of industrialized democracies in mind is presented to adolescents in a Latin American country (Venezuela). Some strategies for addressing these challenges are outlined

    Optimal static and dynamic recycling of defective binary devices

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    The binary Defect Combination Problem consists in finding a fully working subset from a given ensemble of imperfect binary components. We determine the typical properties of the model using methods of statistical mechanics, in particular, the region in the parameter space where there is almost surely at least one fully-working subset. Dynamic recycling of a flux of imperfect binary components leads to zero wastage.Comment: 14 pages, 15 figure

    Stress reactivity elicits a tissue-specific reduction in telomere length in aging zebrafish (Danio rerio).

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    Individual differences in personality are associated with variation in healthy aging. Health behaviours are often cited as the likely explanation for this association; however, an underlying biological mechanism may also exist. Accelerated leukocyte telomere shortening is implicated in multiple age-related diseases and is associated with chronic activation of the hypothalamus-pituitary-adrenal (HPA) axis, providing a link between stress-related personality differences and adverse health outcomes. However, the effects of the HPA axis are tissue specific. Thus, leukocyte telomere length may not accurately reflect telomere length in disease-relevant tissues. Here, we examined the correlation between stress reactivity and telomere length in heart and brain tissue in young (6-9 month) and aging (18 month) zebrafish. Stress reactivity was assessed by tank diving and through gene expression. Telomere length was assessed using quantitative PCR. We show that aging zebrafish have shorter telomeres in both heart and brain. Telomere length was inversely related to stress reactivity in heart but not brain of aging individuals. These data support the hypotheses that an anxious predisposition contributes to accelerated telomere shortening in heart tissue, which may have important implications for our understanding of age-related heart disease, and that stress reactivity contributes to age-related telomere shortening in a tissue-specific manner

    Estrategias Pedagógicas para el Fortalecimiento de Valores a través de Juegos Tradicionales en Educandos de Educación Inicial

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    El propósito del estudio fue proponer estrategias pedagógicas para el fortalecimiento de valores de tolerancia, respeto, responsabilidad, solidaridad y honestidad a través de juegos tradicionales en educandos de Educación Inicial de la Escuela Básica Nacional José Ángel Huerta del Municipio Mara del Estado Zulia. Bajo los postulados de: Maestro (2005), Monroy (2005), Izquierdo (2003)., entre otros. Asentado bajo el enfoque positivista, de tipo descriptiva, diseño no experimental, transversal, de campo. La muestra seis (06) docentes de Educación Inicial. Se Aplicó un cuestionario de (12) ítems, sometido a validez de expertos, su confiabilidad a través del coeficiente alfa cronbach, (0.92) Los resultados obtenidos determinaron que: los sujetos investigados hacen poco uso de estrategias que incluyan el juego para enseñar valores, escasamente reconocen el juego como estrategia pedagógica que facilita el aprendizaje, no incluyen juegos tradicionales en situaciones de aprendizaje

    Total Degree Formula for the Generic Offset to a Parametric Surface

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    We provide a resultant-based formula for the total degree w.r.t. the spatial variables of the generic offset to a parametric surface. The parametrization of the surface is not assumed to be proper.Comment: Preprint of an article to be published at the International Journal of Algebra and Computation, World Scientific Publishing, DOI:10.1142/S021819671100680

    Deep Learning versus Classical Regression for Brain Tumor Patient Survival Prediction

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    Deep learning for regression tasks on medical imaging data has shown promising results. However, compared to other approaches, their power is strongly linked to the dataset size. In this study, we evaluate 3D-convolutional neural networks (CNNs) and classical regression methods with hand-crafted features for survival time regression of patients with high grade brain tumors. The tested CNNs for regression showed promising but unstable results. The best performing deep learning approach reached an accuracy of 51.5% on held-out samples of the training set. All tested deep learning experiments were outperformed by a Support Vector Classifier (SVC) using 30 radiomic features. The investigated features included intensity, shape, location and deep features. The submitted method to the BraTS 2018 survival prediction challenge is an ensemble of SVCs, which reached a cross-validated accuracy of 72.2% on the BraTS 2018 training set, 57.1% on the validation set, and 42.9% on the testing set. The results suggest that more training data is necessary for a stable performance of a CNN model for direct regression from magnetic resonance images, and that non-imaging clinical patient information is crucial along with imaging information.Comment: Contribution to The International Multimodal Brain Tumor Segmentation (BraTS) Challenge 2018, survival prediction tas

    Prefrontal cortex and behavioral disorders: Theoretical framework and neuropsychological evaluation

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    Los trastornos del córtex prefrontal (CPF) permiten explicar la sintomatología de importantes cuadros neurológicos y psiquiátricos, tales como las secuelas de traumatismos encéfalo-craneanos y las esquizofrenias. Sin embargo, y a pesar de la gran importancia de sus funciones, su estudio se ha visto dificultado por razones teóricas, experimentales y clínicas. Recientemente han surgido dos nuevos modelos que intentan explicar los mecanismos a la base del funcionamiento del CPF. Presentamos una revisión de las principales manifestaciones clínicas ante su disfunción, los modelos explicativos postulados tradicionalmente, además de las dos propuestas recientes de Koechlin y Mesulam, para finalizar con una revisión de los instrumentos más utilizados en el ámbito clínico para la evaluación de las funciones propias de esta región, denominadas funciones ejecutivas y de autorregulación del comportamiento Dysfunction of prefrontal cortex explains the symptoms of many neurological and psychiatric disorders, such as the consequences of cerebral trauma and schizophrenia. Although the importance of frontal lobe functions in complex cognition has long been recognized, systematic research efforts to specify the nature, organization and roles of these functions have been difficult for theoretical, experimental and clinical reasons. Recently, two new theoretical frameworks have been proposed to explain the role of prefrontal cortex. In this paper, we present a revision of the main clinical manifestations secondary to prefrontal dysfunction, the frameworks proposed by Mesulam and Koechlin to explain the role of prefrontal cortex in behavior and the principal instruments available to evaluate executive and strategic self-regulation function

    Evidence for global cooling in the Late Cretaceous.

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    The Late Cretaceous ‘greenhouse’ world witnessed a transition from one of the warmest climates of the past 140 million years to cooler conditions, yet still without significant continental ice. Low-latitude sea surface temperature (SST) records are a vital piece of evidence required to unravel the cause of Late Cretaceous cooling, but high-quality data remain illusive. Here, using an organic geochemical palaeothermometer (TEX86), we present a record of SSTs for the Campanian–Maastrichtian interval (~83–66¿Ma) from hemipelagic sediments deposited on the western North Atlantic shelf. Our record reveals that the North Atlantic at 35¿°N was relatively warm in the earliest Campanian, with maximum SSTs of ~35¿°C, but experienced significant cooling (~7¿°C) after this to <~28¿°C during the Maastrichtian. The overall stratigraphic trend is remarkably similar to records of high-latitude SSTs and bottom-water temperatures, suggesting that the cooling pattern was global rather than regional and, therefore, driven predominantly by declining atmospheric pCO2 levels

    EVALUATION OF TWO VACCINATION PROGRAMS USING THE INFECTIOUS BURSAL DISEASE 2512 STRAIN AGAINST EXPERIMENTAL INFECTION WITH THE F52/70 STRAIN

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    El objetivo del presente estudio fue evaluar la inmunoprotección conferida por dos programas de vacunación en pollos de carne, con diferentes vacunas comerciales del virus de la Enfermedad Infecciosa de la Bursa (EIB). El grupo A fue vacunado con la cepa 2512 (intermedia-fuerte) a los 19 días de edad; el grupo B fue vacunado a los 10 días con la cepa 2512 (intermedia-intermedia) y a los 19 días con la cepa 228TC (intermedia-intermedia); y el grupo C fue el control no vacunado. Los tres grupos fueron desafiados a los 32 días de edad con la cepa estándar F52/70 de la EIB. La protección fue medida a través de signos clínicos (diarrea), tamaño de la bursa, índice bursal, lesiones histopatológicas en bursa, parámetros productivos y títulos de anticuerpos. El tamaño e índice bursal al 7o día del desafío en los 3 grupos fueron compatibles con atrofia bursal, aunque no afectaron mayormente los parámetros productivos. El peso corporal y los títulos de anticuerpos al final del estudio fueron similares en los grupos A y B, no existiendo diferencia estadística significativa (p&gt;0.05) entre ellos. Los resultados obtenidos de las lesiones bursales, histopatología, índice bursal, parámetros productivos y títulos de anticuerpos indicaron que tanto las aves del grupo A como las del grupo B estuvieron protegidas contra el virus de desafío.The objective of the present study was to evaluate the immunoprotection given by two vaccination programs in broilers, using comercial vaccines against the infectious bursal disease virus (IBDV). In group A, the strain 2512 (intermediate plus) was inoculated at 19 days of age; in group B was used two intermediate-intermediate vaccines: the strain 2512 at day 10 and the strain 228TC at day 19; and group C was used as the nonvaccinated control group. The three groups were challenged at day 32 with the standard strain F52/70 of IBDV. The protection was measured after the challenge through clinical signs (diarrhea), size of the bursa, bursal index, productive parameters and antibody titers. The size and the bursal index at 7 days post challenge in the three groups showed bursal atrophy but this, did not significantly affect productive parameters. Groups A and B had similar body weights and antibody titers at day 49 (p&gt;0.05). The results obtained in bursal damage, histopathology, bursal index, productive parameters, and antibody titers indicated that chicks of groups A and B were protected against the IBDV strain of challenge

    Effects of Biological Therapies on Molecular Features of Rheumatoid Arthritis

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    Rheumatoid arthritis (RA) is an autoimmune and chronic inflammatory disease primarily affecting the joints, and closely related to specific autoantibodies that mostly target modified self-epitopes. Relevant findings in the field of RA pathogenesis have been described. In particular, new insights come from studies on synovial fibroblasts and cells belonging to the innate and adaptive immune system, which documented the aberrant production of inflammatory mediators, oxidative stress and NETosis, along with relevant alterations of the genome and on the regulatory epigenetic mechanisms. In recent years, the advances in the understanding of RA pathogenesis by identifying key cells and cytokines allowed the development of new targeted disease-modifying antirheumatic drugs (DMARDs). These drugs considerably improved treatment outcomes for the majority of patients. Moreover, numerous studies demonstrated that the pharmacological therapy with biologic DMARDs (bDMARDs) promotes, in parallel to their clinical efficacy, significant improvement in all these altered molecular mechanisms. Thus, continuous updating of the knowledge of molecular processes associated with the pathogenesis of RA, and on the specific effects of bDMARDs in the correction of their dysregulation, are essential in the early and correct approach to the treatment of this complex autoimmune disorder. The present review details basic mechanisms related to the physiopathology of RA, along with the core mechanisms of response to bDMARDs
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