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Search Results: 1 - 10 of 44684 matches for " Juan Jose Rodriguez-Vazquez "
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Application of GPUs for the Calculation of Two Point Correlation Functions in Cosmology
Rafael Ponce,Miguel Cardenas-Montes,Juan Jose Rodriguez-Vazquez,Eusebio Sanchez,Ignacio Sevilla
Physics , 2012,
Abstract: In this work, we have explored the advantages and drawbacks of using GPUs instead of CPUs in the calculation of a standard 2-point correlation function algorithm, which is useful for the analysis of Large Scale Structure of galaxies. Taking into account the huge volume of data foreseen in upcoming surveys, our main goal has been to accelerate significantly the analysis codes. We find that GPUs offer a 100-fold increase in speed with respect to a single CPU without a significant deviation in the results. For comparison's sake, an MPI version was developed as well. Some issues, like code implementation, which arise from using this option are discussed.
Local quanta, unitary inequivalence, and vacuum entanglement
Matias Rodriguez-Vazquez,Marco del Rey,Hans Westman,Juan Leon
Physics , 2014, DOI: 10.1016/j.aop.2014.07.031
Abstract: In this work we develop a formalism for describing localised quanta for a real-valued Klein-Gordon field in a one-dimensional box $[0, R]$. We quantise the field using non-stationary local modes which, at some arbitrarily chosen initial time, are completely localised within the left or the right side of the box. In this concrete set-up we directly face the problems inherent to a notion of local field excitations, usually thought of as elementary particles. Specifically, by computing the Bogoliubov coefficients relating local and standard (global) quantizations, we show that the local quantisation yields a Fock space $\mathfrak F^L$ which is unitarily inequivalent to the standard one $\mathfrak F^G$. In spite of this, we find that the local creators and annihilators remain well defined in the global Fock space $\mathfrak F^G$, and so do the local number operators associated to the left and right partitions of the box. We end up with a useful mathematical toolbox to analyse and characterise local features of quantum states in $\mathfrak F^G$. Specifically, an analysis of the global vacuum state $|0_G\rangle\in\mathfrak F^G$ in terms of local number operators shows, as expected, the existence of entanglement between the left and right regions of the box. The local vacuum $|0_L\rangle\in\mathfrak F^L$, on the contrary, has a very different character. It is neither cyclic nor separating and displays no entanglement. Further analysis shows that the global vacuum also exhibits a distribution of local excitations reminiscent, in some respects, of a thermal bath. We discuss how the mathematical tools developed herein may open new ways for the analysis of fundamental problems in local quantum field theory.
Cosmological signature change in Cartan Gravity with dynamical symmetry breaking
Joao Magueijo,Matias Rodriguez-Vazquez,Hans Westman,T. G. Zlosnik
Physics , 2013, DOI: 10.1103/PhysRevD.89.063542
Abstract: We investigate the possibility for classical metric signature change in a straightforward generalization of the first order formulation of gravity, dubbed "Cartan gravity". The mathematical structure of this theory mimics the electroweak theory in that the basic ingredients are an $SO(1,4)$ Yang-Mills gauge field $A^{ab}_{\phantom{ab}\mu}$ and a symmetry breaking Higgs field $V^{a}$, with no metric or affine structure of spacetime presupposed. However, these structures can be recovered, with the predictions of General Relativity exactly reproduced, whenever the Higgs field breaking the symmetry to $SO(1,3)$ is forced to have a constant (positive) norm $V^aV_a$. This restriction is usually imposed "by hand", but in analogy with the electroweak theory we promote the gravitational Higgs field $V^a$ to a genuine dynamical field, subject to non-trivial equations of motion. Even though we limit ourselves to actions polynomial in these variables, we discover a rich phenomenology. Most notably we derive classical cosmological solutions exhibiting a smooth transition between Euclidean and Lorentzian signature in the four-metric. These solutions are non-singular and arise whenever the $SO(1,4)$ norm of the Higgs field changes sign i.e. the signature of the metric of spacetime is determined dynamically by the gravitational Higgs field. It is possible to find a plethora of such solutions and in some of them this dramatic behaviour is confined to the early universe, with the theory asymptotically tending to Einstein gravity at late times. Curiously the theory can also naturally embody a well-known dark energy model: Peebles-Ratra quintessence.
The shrinking human protein coding complement: are there now fewer than 20,000 genes?
Iakes Ezkurdia,David Juan,Jose Manuel Rodriguez,Adam Frankish,Mark Diekhans,Jennifer Harrow,Jesus Vazquez,Alfonso Valencia,Michael L. Tress
Quantitative Biology , 2013,
Abstract: Determining the full complement of protein-coding genes is a key goal of genome annotation. The most powerful approach for confirming protein coding potential is the detection of cellular protein expression through peptide mass spectrometry experiments. Here we map the peptides detected in 7 large-scale proteomics studies to almost 60% of the protein coding genes in the GENCODE annotation the human genome. We find that conservation across vertebrate species and the age of the gene family are key indicators of whether a peptide will be detected in proteomics experiments. We find peptides for most highly conserved genes and for practically all genes that evolved before bilateria. At the same time there is almost no evidence of protein expression for genes that have appeared since primates, or for genes that do not have any protein-like features or cross-species conservation. We identify 19 non-protein-like features such as weak conservation, no protein features or ambiguous annotations in major databases that are indicators of low peptide detection rates. We use these features to describe a set of 2,001 genes that are potentially non-coding, and show that many of these genes behave more like non-coding genes than protein-coding genes. We detect peptides for just 3% of these genes. We suggest that many of these 2,001 genes do not code for proteins under normal circumstances and that they should not be included in the human protein coding gene catalogue. These potential non-coding genes will be revised as part of the ongoing human genome annotation effort.
Aproximación al derecho concursal colombiano.
Juan Jose Rodriguez Espitia
Revista e-Mercatoria , 2007,
Abstract: Con ocasión de la reciente modificación a que se vió sometido el régimen concursal colombiano, el presente artículo pretende aprovechar esa oportunidad con el propósito de abordar algunos temas relacionados con la insolvencia empresarial, y que no obstante ser a ejos, a raíz de la mentada reforma, readquieren vigencia académica. El autor pretende mediante una aproximación histórica completada de referencias prácticas, poner de presente al lector temas y puntos álgidos que dentro de la evolución del derecho concursal se encuentran aún en punto de discusión.
Some Free Boundary Problems involving Nonlocal Diffusion and Aggregation
Jose Antonio Carrillo,Juan Luis Vazquez
Mathematics , 2015,
Abstract: We report on recent progress in the study of evolution processes involving degenerate parabolic equations what may exhibit free boundaries. The equations we have selected follow to recent trends in diffusion theory: considering anomalous diffusion with long-range effects, which leads to fractional operators or other operators involving kernels with large tails; and the combination of diffusion and aggregation effects, leading to delicate long-term equilibria whose description is still incipient.
Utilización del ELISA y el ultramicroELISA en la identificación de una cepa de Coxsackie A9 aislada durante la epidemia de neuropatía en Cuba
BALMASEDA,ANGEL; LAFERTE,JOSE; SOLER,MARITZA; VAZQUEZ,SUSANA; RODRIGUEZ,LICEL; OTERO,ANSELMO; VAZQUEZ,VALEXIS;
Revista Cubana de Medicina Tropical , 1995,
Abstract: durante 1993, nuestro país se vio afectado por un brote de neuropatía epidémica (ne) caracterizado por 2 formas clínicas fundamentales: óptica y periférica. aunque la causa de la enfermedad fue considerada multifactorial (fundamentalmente agentes neurotóxicos y deficiencia nutricional), fue aislado un enterovirus del líquido cefalorraquídeo de un paciente (cepa 47/93, ipk), el cual fue posteriormente clasificado como coxsackie a9 (cox a9) mediante la prueba de neutralización (nt) utilizando los pools de suero de lim benyesh melnick (lbm). se presentan los resultados obtenidos durante la aplicación del elisa y del ultramicroelisa en la identificación de este agente a partir del sobrenadante de cultivo de células infectadas, así como en la detección de anticuerpos a la cepa en poblaciones con baja y alta incidencias de la enfermedad.
A fractional porous medium equation
Arturo de Pablo,Fernando Quiros,Ana Rodriguez,Juan Luis Vazquez
Mathematics , 2010,
Abstract: We develop a theory of existence, uniqueness and regularity for a porous medium equation with fractional diffusion, $\frac{\partial u}{\partial t} + (-\Delta)^{1/2} (|u|^{m-1}u)=0$ in $\mathbb{R}^N$, with $m>m_*=(N-1)/N$, $N\ge1$ and $f\in L^1(\mathbb{R}^N)$. An $L^1$-contraction semigroup is constructed and the continuous dependence on data and exponent is established. Nonnegative solutions are proved to be continuous and strictly positive for all $x\in\mathbb{R}^N$, $t>0$.
UniDA: Uniform Device Access Framework for Human Interaction Environments
Gervasio Varela,Alejandro Paz-Lopez,Jose Antonio Becerra,Santiago Vazquez-Rodriguez,Richard José Duro
Sensors , 2011, DOI: 10.3390/s111009361
Abstract: Human interaction environments (HIE) must be understood as any place where people carry out their daily life, including their work, family life, leisure and social life, interacting with technology to enhance or facilitate the experience. The integration of technology in these environments has been achieved in a disorderly and incompatible way, with devices operating in isolated islands with artificial edges delimited by the manufacturers. In this paper we are presenting the UniDA framework, an integral solution for the development of systems that require the integration and interoperation of devices and technologies in HIEs. It provides developers and installers with a uniform conceptual framework capable of modelling an HIE, together with a set of libraries, tools and devices to build distributed instrumentation networks with support for transparent integration of other technologies. A series of use case examples and a comparison to many of the existing technologies in the field has been included in order to show the benefits of using UniDA.
Identificación por ELISA de agentes productores de efecto citopático ligero aislados durante la epidemia de neuropatía en Cuba. 1991
GONZALEZ,GREHETE; LAFERTE,JOSE; MAS,PEDRO; VAZQUEZ,VALEXYS; RODRIGUEZ,ROSMARI; MIGUEZ,JOHANDRA;
Revista Cubana de Medicina Tropical , 1996,
Abstract: using as a reference the strain 44/93 isolated during the neuropathy epidemy in 1991 and characterized as a producer of a light cytopathic effect (l-cpe), it was possible the standardization of an elisa for the fast identification of other strains with similar effect. the assay consisted in a sandwich-type elisa where the conditions selected for each reactive (10 mg/ml for the coating antibody, 1 mg/ml for the antigen, and dilution 1/2 000 for the conjugate) allowed to have an adequate discrimination between the antigen and the antigen control for the reference strain used. the evaluation of a panel of reference viral strains and of other l-cpe-producing strains showed a 100 % of coincidence between this method and the isolation in cellular culture. the results obtained permit us to recommed the use of this assay as a more precise alternative to identify these agents.
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