3,931 research outputs found
Optimal Hoeffding bounds for discrete reversible Markov chains
We build optimal exponential bounds for the probabilities of large deviations
of sums \sum_{k=1}^nf(X_k) where (X_k) is a finite reversible Markov chain and
f is an arbitrary bounded function. These bounds depend only on the stationary
mean E_{\pi}f, the end-points of the support of f, the sample size n and the
second largest eigenvalue \lambda of the transition matrix
Electrodeposition of copper from mixed sulphate–chloride acidic electrolytes at rotating disc electrode
The effect of chloride ion on the deposition of copper from low metal concentrations in aqueous, acid sulphate solutions was investigated. The electrolytes contained 0·05 mol dm?3 CuSO4 and 0·5 mol dm?3 Na2SO4 at pH 2 and 296 K. The chloride ion concentration was varied in a wide range from 0·03 to 2·0 mol dm?3. Linear sweep voltammetry was carried out under well defined flow conditions at a smooth platinum rotating disc electrode. The progressive transition from a single, two-electron reaction for the reduction of Cu(II)?Cu(0) to two, single-electron reactions for the reduction sequence: Cu(II)?Cu(I)?Cu(0) was clearly evident as the chloride ion concentration increased. The charge transfer and mass transport characteristics of these reactions were evaluated. The formal potential for the Cu II) reduction to Cu(I), the shift in the potential region for complete mass transport controlled reduction of Cu(I) to Cu(0) and the potential for hydrogen evolution at the deposited copper were also studied. A semi-logarithmic relationship between exchange current density and half-wave potential for Cu(II)?Cu(I) with chloride ion was achieved when the Cl?/Cu(II) ratio in the electrolytes exceeded 2, due to the presence of the Cu(I) dichlorocuprous anion, CuCl2?
Phase space analysis of quintessence fields trapped in a Randall-Sundrum Braneworld: anisotropic Bianchi I brane with a Positive Dark Radiation term
In this paper we investigate, from the dynamical systems perspective, the
evolution of an scalar field with arbitrary potential trapped in a
Randall-Sundrum's Braneworld of type 2. We consider an homogeneous but
anisotropic Bianchi I (BI) brane filled also with a perfect fluid. We also
consider the effect of the projection of the five-dimensional Weyl tensor onto
the three-brane in the form of a positive Dark Radiation term. Using the center
manifold theory we obtain sufficient conditions for the asymptotic stability of
de Sitter solution with standard 4D behavior. We also prove that there are not
late time de Sitter attractors with 5D-modifications since they are always
saddle-like. This fact correlates with a transient primordial inflation. We
present here sufficient conditions on the potential for the stability of the
scalar field-matter scaling solution, the scalar field-dominated solution, and
the scalar field-dark radiation scaling solution. We illustrate our analytical
findings using a simple -deviser as a toy model. All these results are
generalizations of our previous results obtained for FRW branes.Comment: 14 pages, 11 figures, one affiliation added, matches the published
version at CQG. arXiv admin note: substantial text overlap with
arXiv:1110.173
El paso de la razón a la función trigonométrica: revisión de algunos elementos históricos en la construcción de la función trigonométrica
La noción de función trigonométrica ha estado asociada a diversas prácticas que la han convertido en un concepto complejo que tiene sus orígenes en los primeros cálculos astronómicos y que adquiere su formalización con el planteamiento de respuestas a problemas generados en contextos físicos. El análisis de los episodios asociados a la evolución del concepto de función trigonométrica nos permite identificar una serie de herramientas que se vuelven pertinentes para el planteamiento de escenarios en donde se resignifiquen algunas características de la función en torno a su uso y a una nueva interpretación de la misma
ALICE Diffractive Detector Control System for RUN-II in the ALICE Experiment
This paper describes general characteristics of the deployment and
commissioned of the Detector Control System (DCS) AD0 for the second phase of
the Large Hadron Collider (LHC). The AD0 detector is installed in the ALICE
experiment to provide a better selection of diffractive events.Comment: 4 pages, 5 figures, To be published in Journal of Physics Conference
Series (IOP). Joint Proceedings of the XV Mexican Workshop on Particles and
Fields & the XXX Annual Meeting of the Division of Particles and Fields of
the Mexican Physical Societ
Some applications of semi-discrete variational integrators to classical field theories
We develop a semi-discrete version of discrete variational mechanics with
applications to numerical integration of classical field theories. The
geometric preservation properties are studied.Comment: 14 page
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