Search results for " Statistical"
showing 10 items of 1649 documents
Structural and dynamical properties of sodium silicate melts: An investigation by molecular dynamics computer simulation
2001
We present the results of large scale computer simulations in which we investigate the static and dynamic properties of sodium disilicate and sodium trisilicate melts. We study in detail the static properties of these systems, namely the coordination numbers, the temperature dependence of the Q^(n) species and the static structure factor, and compare them with experiments. We show that the structure is described by a partially destroyed tetrahedral SiO_4 network and the homogeneously distributed sodium atoms which are surrounded on average by 16 silicon and other sodium atoms as nearest neighbors. We compare the diffusion of the ions in the sodium silicate systems with that in pure silica a…
Theory of the growth mode for a thin metallic film on an insulating substrate
2002
We have developed a novel theory predicting the growth mode of a thin metallic film on an insulating substrate. This combines ab initio electronic structure calculations for several ordered metal/insulator interfaces (varying both coverage and substrate lattice constant), with a thermodynamic approach based on microscopic calculations. We illustrate this approach for Ag film deposited on MgO(0 0 1) substrate. Ab initio calculations predict high mobility of adsorbed silver atoms on the perfect magnesia surface even at low temperatures. Our theoretical analysis clearly demonstrates that the growth of metallic islands is predominant at the initial stage of silver deposition, which agrees with …
Incidence of DAA failure and the clinical impact of retreatment in real-life patients treated in the advanced stage of liver disease: Interim evaluat…
2017
Background: Few data are available on the virological and clinical outcomes of advanced liver disease patients retreated after first-line DAA failure. Aim: To evaluate DAA failure incidence and the retreatment clinical impact in patients treated in the advanced liver disease stage. Methods: Data on HCV genotype, liver disease severity, and first and second line DAA regimens were prospectively collected in consecutive patients who reached the 12-week post-treatment and retreatment evaluations from January 2015 to December 2016 in 23 of the PITER network centers. Results: Among 3,830 patients with advanced fibrosis (F3) or cirrhosis, 139 (3.6%) failed to achieve SVR. Genotype 3, bilirubin lev…
Predicting school students’ physical activity intentions in leisure-time and school recess contexts: Testing an integrated model based on self-determ…
2021
BackgroundIdentifying psychological correlates of children's physical activity intentions may signpost potentially modifiable targets for interventions aimed at promoting physical activity participation. School recess and leisure-time outside of school are appropriate contexts in which such interventions may be delivered. However, few studies have identified correlates of physical activity intentions in these environments. Examining correlates in these contexts may provide formative evidence on which to base interventions to promote physical activity.PurposeThe current study adopted an integrated theoretical model to test relations between motivational constructs from self-determination the…
Análisis de la realidad sociolingüística del valenciano
2011
Se analiza la situación actual del uso y la percepción social del valenciano entre los habitantes del País Valenciano a partir de los estudios realizados por el Centro de Investigaciones Sociológicas. Para ello, se presta especial atención a variables sociodemográficas a partir de análisis estadístico multivariante con distribuciones de frecuencias bivariadas, análisis de segmentación y regresión logística. El estudio concluye que se produce un estancamiento en el porcentaje de hablantes del valenciano y que las personas de izquierdas y con mayor nivel de estudios son quienes se postulan más a favor de la unidad del valenciano con el catalán. Palabras clave: sociolingüística; diglosia; esta…
A typology of theatre audiences based on the impact of various sources of influence and the use of information channels
2020
En: Doxa Comunicación: revista interdisciplinar de estudios de comunicación y ciencias sociales. e-ISSN 2386-3978 n. 30, 2020, pp 127-143. Este estudio presenta una tipología de espectadores teatrales que contempla la influencia de los medios de comunicación y otras instancias de prescripción en sus decisiones de asistencia al teatro, un aspecto no abordado por ninguna investigación previa. La investigación se basa en una encuesta a 210 asistentes a representaciones teatrales de tres salas de la ciudad de Valencia. La aplicación de diversas técnicas estadísticas multivariables ha permitido identificar una tipología de cuatro perfiles de consumidores escénicos: los informados-alternativos, l…
Southern-Tyrrhenian seismicity in space-time-magnitude domain
2006
An analysis is conducted on a catalogue containing more than 2000 seismic events occurred in the southern Tyrrhenian Sea between 1988 and October 2002, as an attempt to characterise the main seismogenetic processes active in the area in space, time and magnitude domain by means of the parameters of phenomenological laws. We chose to adopt simple phenomenological models, since the low number of data did not allow to use more complex laws. The two main seismogenetic volumes present in the area were considered for the purpose of this work. The first includes a nearly homogeneous distribution of hypocentres in a NW steeply dipping layer as far as a…
Topology of correlation-based minimal spanning trees in real and model markets
2003
We present here a topological characterization of the minimal spanning tree that can be obtained by considering the price return correlations of stocks traded in a financial market. We compare the minimal spanning tree obtained from a large group of stocks traded at the New York Stock Exchange during a 12-year trading period with the one obtained from surrogated data simulated by using simple market models. We find that the empirical tree has features of a complex network that cannot be reproduced, even as a first approximation, by a random market model and by the one-factor model.
Statistical analysis of latency outcomes in behavioral experiments
2011
In experimental designs of animal models, memory is often assessed by the time for a performance measure to occur (latency). Depending on the cognitive test, this may be the time it takes an animal to escape to a hidden platform (water maze), an escape tunnel (Barnes maze) or to enter a dark component (passive avoidance test). Latency outcomes are usually statistically analyzed using ANOVAs. Besides strong distributional assumptions, ANOVA cannot properly deal with animals not showing the performance measure within the trial time, potentially causing biased and misleading results. We propose an alternative approach for statistical analyses of latency outcomes. These analyses have less distr…
Performance potential for simulating spin models on GPU
2012
Graphics processing units (GPUs) are recently being used to an increasing degree for general computational purposes. This development is motivated by their theoretical peak performance, which significantly exceeds that of broadly available CPUs. For practical purposes, however, it is far from clear how much of this theoretical performance can be realized in actual scientific applications. As is discussed here for the case of studying classical spin models of statistical mechanics by Monte Carlo simulations, only an explicit tailoring of the involved algorithms to the specific architecture under consideration allows to harvest the computational power of GPU systems. A number of examples, ran…