6,365 research outputs found
Using synchronization to improve earthquake forecasting in a cellular automaton model
A new forecasting strategy for stochastic systems is introduced. It is
inspired by the concept of anticipated synchronization between pairs of chaotic
oscillators, recently developed in the area of Dynamical Systems, and by the
earthquake forecasting algorithms in which different pattern recognition
functions are used for identifying seismic premonitory phenomena. In the new
strategy, copies (clones) of the original system (the master) are defined, and
they are driven using rules that tend to synchronize them with the master
dynamics. The observation of definite patterns in the state of the clones is
the signal for connecting an alarm in the original system that efficiently
marks the impending occurrence of a catastrophic event. The power of this
method is quantitatively illustrated by forecasting the occurrence of
characteristic earthquakes in the so-called Minimalist Model.Comment: 4 pages, 3 figure
Expansion velocity of a one-dimensional, two-component Fermi gas during the sudden expansion in the ballistic regime
We show that in the sudden expansion of a spin-balanced two-component Fermi
gas into an empty optical lattice induced by releasing particles from a trap,
over a wide parameter regime, the radius of the particle cloud grows
linearly in time. This allow us to define the expansion velocity from
. The goal of this work is to clarify the dependence of the
expansion velocity on the initial conditions which we establish from
time-dependent density matrix renormalization group simulations, both for a box
trap and a harmonic trap. As a prominent result, the presence of a
Mott-insulating region leaves clear fingerprints in the expansion velocity. Our
predictions can be verified in experiments with ultra-cold atoms.Comment: 8 pages 10 figures, version as published with minor stylistic change
Three-dimensional numerical simulation of 1GeV/Nucleon U92+ impact against atomic hydrogen
The impact of 1GeV/Nucleon U92+ projectiles against atomic hydrogen is
studied by direct numerical resolution of the time-dependent wave equation for
the atomic electron on a three-dimensional Cartesian lattice. We employ the
fully relativistic expressions to describe the electromagnetic fields created
by the incident ion. The wave equation for the atom interacting with the
projectile is carefully derived from the time-dependent Dirac equation in order
to retain all the relevant terms.Comment: 12 pages and 7 figures included in the tex
EstrellaNueva: an open-source software to study the interactions and detection of neutrinos emitted by supernovae
Supernovae emit large fluxes of neutrinos which can be detected by detectors
on Earth. Future tonne-scale detectors will be sensitive to several neutrino
interaction channels, with thousands of events expected if a supernova emerges
in the galaxy neighborhood. There is a limited number of tools to study the
interaction rates of supernova neutrinos, although a plethora of available
supernova models exists. EstrellaNueva is an open-source software to calculate
expected rates of supernova neutrinos in detectors using target materials with
typical compositions, and additional compositions can be easily added. This
software considers the flavor transformation of neutrinos in the supernova
through the adiabatic Mikheyev--Smirnov--Wolfenstein effect, and their
interaction in detectors through several channels. Most of the interaction
cross sections have been analytically implemented, such as neutrino-electron
and neutrino-proton elastic scattering, inverse beta decay, and coherent
elastic neutrino-nucleus scattering. This software provides a link between
supernova simulations and the expected events in detectors by calculating
fluences and event rates to ease any comparison between theory and observation.
It provides a simple and standalone tool to explore many physics scenarios
offering an option to add analytical cross sections and define any target
material
Self-organized criticality and directed percolation
A sandpile model with stochastic toppling rule is studied. The control
parameters and the phase diagram are determined through a MF approach, the
subcritical and critical regions are analyzed. The model is found to have some
similarities with directed percolation, but the existence of different boundary
conditions and conservation law leads to a different universality class, where
the critical state is extended to a line segment due to self-organization.
These results are supported with numerical simulations in one dimension. The
present model constitute a simple model which capture the essential difference
between ordinary nonequilibrium critical phenomena, like DP, and self-organized
criticality.Comment: 9 pages, 10 eps figs, revtex, submitted to J. Phys.
Decision-making in school-age sport measured through a digital tool.
El objetivo de este estudio ha sido doble. Por un lado, diseñar y crear un
software de evaluación de toma de decisiones en edad escolar, en base a
aspectos espacio-temporales, contextualizado en voleibol, denominado “Juego
Interactivo de Voleibol”. Por otro lado, analizar y establecer su fiabilidad y validez.
El software diseñado se aplicó a una muestra de 132 escolares (64 niños y 68
niñas) de entre 10 y 13 años, de los centros educativos públicos de Educación
Primaria y Secundaria de las localidades sevillanas de Arahal y Paradas
(España). Para determinar la fiabilidad se estudió la consistencia interna a través
del coeficiente alfa de Cronbach. Para calcular el número óptimo de repeticiones
se utilizó el Coeficiente de Correlación Intraclase. La validez se comprobó en
base a la evaluación de un grupo de 5 expertos. Los resultados indicaron que
este nuevo software de evaluación alcanza altos niveles de fiablidad y validezThe aim of this study was twofold. On the one hand, the design and creation of
an evaluation software for decision-making in school-age children based on
spatial-temporal aspects in the context of volleyball called ‘Interactive Volleyball
Game’. On the other hand, the analysis and establishment of its reliability and
validity. The designed software was applied to a sample of 132 students (64
boys and 68 girls) aged between 10 and 13 years in public Elementary and
Secondary Education schools of Seville towns, Arahal and Paradas (Spain). To
determine the reliability, internal consistency was studied through Cronbach's
alpha. The intraclass correlation coefficient (ICC) was also analyzed to calculate
the optimal number of repetitions for future research. The validity was tested
based on the assessment of a group of 5 experts. The results indicated that this
new evaluation software reaches high levels of reliability and validit
Influence of hail suppression systems over silver content in the environment in Aragón (Spain). II: Water, sediments and biota
The silver content in soils in the area in the surroundings of the Gallocanta Lake (Aragón, NE Spain) is lower than expected considering the estimated silver emission during the last 50 years by hail suppression systems. To understand the silver accumulation processes, selected water (4 surface, 3 groundwater), biota and sediment (6 surface sediments and 3 cores from Gallocanta and Campillo de Dueñas Lakes and Used Reservoir) samples have been analysed. An essay comparing the growth of wheat in pots with different silver iodide concentrations has been carried out. Finally, silver content in 7 tissues from two sheep that graze in areas both with and without hail suppression systems during 6–8 years were analysed. Our results show that after 50 years of silver iodide emissions to the atmosphere, silver accumulation in the waters and sediments of the lowlands, including some wetlands of high ecological value, has not been significant. Sediment cores did not show any peaks associated to silver emission. We propose that constant absorption of silver by plants could explain the low concentration in water and sediments. Crops and grass could accumulate the excess silver, as both wheat and sheep are able to absorb significant amounts of silver. These bio - accumulation processes could have helped to avoid a progressive environmental deterioration of the surroundings of the Gallocanta Lake. However, this hypothesis should be corroborated and quantified by further research on the analysis of natural and agricultural areas under the influence of hail suppression systems
The effect of corporate governance factors on the quality of financial reporting in family and non-family firms
The objective of this study is to explore the quality of financial information of Spanish firms, by comparing family firms with non-family firms, and relating this quality with corporate governance practices. For this purpose, a sample of 650 Spanish firms was analysed during the period 2011-2016. Based on agency theory and socioemotional wealth literature, the results show a higher quality of financial information in family firms, a relationship which is reinforced by corporate governance factors. Our results are consistent with the scant previous research, and with the premises of agency theory, which indicate lower asymmetry of information between owners and managers in the singular context of family firms. Additionally, our work provides evidence that the participation of women on the board boosts the quality of financial information in family firms, contributing to the justification of family firm heterogeneity in terms of earnings management. This study contributes to reducing the gap in the literature on the influence of the family business context and the influence of women on the board on the quality of financial reporting.info:eu-repo/semantics/publishedVersio
The impact of corporate social responsibility performance on earnings management: Family versus non-family firms
The study analyses the impact of corporate social responsibility performance on earnings management in family firms as compared with non-family firms. We analysed 650 Spanish firms, listed and unlisted, in the period 2011-2016. The result shows a higher quality of financial information in family firms, a relationship which is reinforced by good governance factors, including the participation of women in management. The factors analysed are supported by agency and institutional theories. The study contributes to reducing the gap in the literature on the quality of financial information associated with family firms vs. non family firms.info:eu-repo/semantics/acceptedVersio
Governação das sociedades e qualidade da informação financeira em empresas familiares versus não familiares
O presente estudo analisa a qualidade da informação financeira em empresas
familiares versus não familiares, relacionando medidas de transparência na
governação das sociedades. Foram analisadas 650 empresas espanholas, cotadas e
não cotadas, no período de 2011-2016. O resultado demonstra a maior qualidade da
informação financeira em empresas familiares, relação que é reforçada pela
participação de mulheres na administração, experiência da empresa e intangibilidade
de ativos. Os fatores analisados estão suportados nas teorias da agência, da riqueza
socio-emocional e institucional. O estudo contribui para reduzir a lacuna na literatura
sobre qualidade da informação financeira associada à governação familiar versus não
familiar.info:eu-repo/semantics/acceptedVersio
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