2,990 research outputs found
Effects of the second virial coefficient on the adiabatic lapse rate of dry atmospheres
We study the effect of the second virial coefficient on the adiabatic lapse
rate of a dry atmosphere. To this end, we compute the corresponding adiabatic
curves, the internal energy, and the heat capacity, among other thermodynamic
parameters. We apply these results to Earth, Mars, Venus, Titan, and the
exoplanet G1 851d, considering three physically relevant virial coefficients in
each case: the hard-sphere, van der Waals, and the square-well potential. These
examples illustrate under which atmospheric conditions the effect of the second
virial coefficient is relevant. Taking the latter into account yields
corrections towards the experimental values of the lapse rates of Venus and
Titan in some instances.Comment: 12 pages, 8 figures. Comments are welcom
Interplay between R513 methylation and S516 phosphorylation of the cardiac voltage-gated sodium channel
Arginine methylation is a novel post-translational modification within the voltage-gated ion channel superfamily, including the cardiac sodium channel, Naᵥ1.5. We show that Naᵥ1.5 R513 methylation decreases S516 phosphorylation rate by 4 orders of magnitude, the first evidence of protein kinase A inhibition by arginine methylation. Reciprocally, S516 phosphorylation blocks R513 methylation. Naᵥ1.5 p.G514C, associated to cardiac conduction disease, abrogates R513 methylation, while leaving S516 phosphorylation rate unchanged. This is the first report of methylation–phosphorylation cross-talk of a cardiac ion channel
Validation of the Scale of Emotional States in the Physical Education Context
The purpose of the present study was to validate an instrument of student emotional experiences in the Spanish Physical Education context. The sample of participants consisted of 864 secondary education students from various educational institutions of Spain who ranged in age from 13 to 19 years. To assess the psychometric properties of the Scale of Emotions in Physical Education (SEPE), various types of analyses were conducted. The factor structure of the SEPE was examined through confirmatory factorial analysis in relation to two models. In the first model, it was proposed that the eight first order factors, which represented the eight emotional states, would be correlated amongst each other. In the second model, an eight-factor model with two higher order factors was proposed, with these higher order factors representing distinct sets of positive and negative emotions. The results provide support the presence of an eight-factor second order model which consisted of sets of four positive emotions and four negative emotions. These results provide evidence for the reliability and validity of the SEPE within the Spanish Physical Education context
Adaptation and Validation of the Mind-Wandering Questionnaire (MWQ) in Physical Education Classes and Analysis of Its Role as Mediator between Teacher and Anxiety
Physical education (PE) classes are one of the primary means of adopting healthy lifestyles and contribute greatly to personal well-being. However, it is necessary that students pay attention and do not enter a mind-wandering state as this can be negative for the purposes of PE classes. Therefore, we adapted and validated the Mind-Wandering Questionnaire (MWQ) to the Spanish PE context and analyzed the influence of the teacher on this new variable. Two independent samples of high school students between the ages of 13 and 19 participated in the study. In order to assess the psychometric properties of the MWQ, various analyses were carried out. The results of the confirmatory factorial analysis (CFA) provided support for the structure of the questionnaire. The structure of the model was gender-invariant. The Cronbach alpha value was higher than 0.70 and showed an adequate level of temporal stability. In addition, we present a second study in which high school students between the ages of 13 and 19 participated, and which are independent of the first study. The analyses in this study were mainly based on structural equation modelling, and demonstrated the teacher’s influence on mind-wandering and showed that mind-wandering acted as a predictor of anxiety in high school students. The results of this study provided evidence of the reliability and validity of the MWQ in the Spanish PE context
Diseño inicial de un instrumento para el diagnóstico y seguimiento de habilidades musicales en estudiantes de pedagogía en educación musical de la Universidad de Concepción
El presente trabajo describe el diseño de una batería de instrumentos destinados a la recopilación de datos para el diagnóstico y posterior seguimiento de los estudiantes de Pedagogía en Educación Musical en la Universidad de Concepción, enmarcado en el Proyecto de Docencia Tipo B 2015-012 “Diagnóstico y seguimiento de habilidades disciplinares en alumnos de primer año de Pedagogía en Educación Musical”. Se trata de la primera etapa de un proyecto de largo alcance que, en este punto, busca proveer la información de base para orientar los procesos de aprendizaje y monitorear la evolución de los estudiantes. Se exponen los factores contextuales que motivan su desarrollo, el marco teórico que lo sustenta y las diferentes secciones que lo componen, enfocándose en el instrumento central de esta batería, desnado a la medición de aptudes musicales en estudiantes que ingresan al primer año de la carrera. Sobre este úlmo test, de elaboración propia, se realiza una descripción general que incluye las dimensiones a evaluar y algunos ejemplos en ítems específicos donde se explican los criterios ulizados en su diseño y las proyecciones académicas de su implementación. Palabras clave: evaluación, habilidades musicales, aptitudes musicales, pedagogía en músic
Identificación de competencias en edición para los profesionales de la información
The identification of competences constitutes one of the key dimensions inside the management of competences. Its objective is to determine the competences an individual requires to excellently perform a specific activity. The present tendencies in the editorial activity, characterized by a growing use of information technologies and communication and a great pressure of the market, impose on information professionals the need to mobilize new and various competences. By means of the application of one of the methodologies used for the management of competences, AMOD, the competences required by the information professionals to carry out the editorial activity were identified. This identification can serve as the basis to redesign the pregraduate curriculum of the careers of library science and information sciences or to create postgraduate courses
Producción científica de Cuba: una perspectiva desde la obra de dos mujeres académicas
Aimed at studying the visibility of the Cuban scientific production, the publications of both, merit and number academic members of the Biomedical Section and of the Natural and Exact Sciences Section of the Cuban Academy of Science, processed in the Scopus database, were identified. Two women, doctors Rosa María Más Ferreiro and María Guadalupe Guzmán, were not only the most productive ones, but also their works had the best impact. These findings corroborated the role played by women in the Cuban science
Benchmarking Particle Filter Algorithms for Efficient Velodyne-Based Vehicle Localization
Keeping a vehicle well-localized within a prebuilt-map is at the core of any autonomous vehicle navigation system. In this work, we show that both standard SIR sampling and rejection-based optimal sampling are suitable for efficient (10 to 20 ms) real-time pose tracking without feature detection that is using raw point clouds from a 3D LiDAR. Motivated by the large amount of information captured by these sensors, we perform a systematic statistical analysis of how many points are actually required to reach an optimal ratio between efficiency and positioning accuracy. Furthermore, initialization from adverse conditions, e.g., poor GPS signal in urban canyons, we also identify the optimal particle filter settings required to ensure convergence. Our findings include that a decimation factor between 100 and 200 on incoming point clouds provides a large savings in computational cost with a negligible loss in localization accuracy for a VLP-16 scanner. Furthermore, an initial density of ∼2 particles/m 2 is required to achieve 100% convergence success for large-scale (∼100,000 m 2 ), outdoor global localization without any additional hint from GPS or magnetic field sensors. All implementations have been released as open-source software
Gene selection and classification of microarray data using random forest
BACKGROUND: Selection of relevant genes for sample classification is a common task in most gene expression studies, where researchers try to identify the smallest possible set of genes that can still achieve good predictive performance (for instance, for future use with diagnostic purposes in clinical practice). Many gene selection approaches use univariate (gene-by-gene) rankings of gene relevance and arbitrary thresholds to select the number of genes, can only be applied to two-class problems, and use gene selection ranking criteria unrelated to the classification algorithm. In contrast, random forest is a classification algorithm well suited for microarray data: it shows excellent performance even when most predictive variables are noise, can be used when the number of variables is much larger than the number of observations and in problems involving more than two classes, and returns measures of variable importance. Thus, it is important to understand the performance of random forest with microarray data and its possible use for gene selection. RESULTS: We investigate the use of random forest for classification of microarray data (including multi-class problems) and propose a new method of gene selection in classification problems based on random forest. Using simulated and nine microarray data sets we show that random forest has comparable performance to other classification methods, including DLDA, KNN, and SVM, and that the new gene selection procedure yields very small sets of genes (often smaller than alternative methods) while preserving predictive accuracy. CONCLUSION: Because of its performance and features, random forest and gene selection using random forest should probably become part of the "standard tool-box" of methods for class prediction and gene selection with microarray data
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