Results for "Raul Ures"

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Ergodicity and partial hyperbolicity on Seifert manifoldsJul 10 2019We show that conservative partially hyperbolic diffeomorphism isotopic to the identity on Seifert 3-manifolds are ergodic.
Tensor Products of Cyclic Algebras of Degree 4 and their Kummer SubspacesFeb 16 2015Jul 08 2016We prove that the maximal dimension of a Kummer space in the generic tensor product of $n$ cyclic algebras of degree 4 is $4 n+1$.
On manifolds supporting quasi Anosov diffeomorphismsOct 11 2001Let $M$ be an $n$-dimensional manifold supporting a quasi Anosov diffeomorphism. If $n=3$ then either $M={\mathbb T}^3$, in which case the diffeomorphisms is Anosov, or else its fundamental group contains a copy of ${\mathbb Z} ^6$. If $n=4$ then $\Pi_1(M)$ ... More
Partially hyperbolic dynamics in dimension 3Jan 05 2015Jan 06 2015Some of the guiding problems in partially hyperbolic diffeomorphisms in 3-manifolds are the following: (1) ergodicity (2) dynamical coherence (3) classification. A few years ago, the last three authors posed conjectures concerning these subjects. In this ... More
Dynamics in the isotopy class of a pseudo-Anosov mapJul 22 2004Despite its homotopical stability, new relevant dynamics appear in the isotopy class of a pseudo-Anosov homeomorphism. We study these new dynamics by identifying homotopically equivalent orbits, obtaining a more complete description of the topology of ... More
Center-unstable foliations do not have compact leavesJan 31 2015For a partiallyhyperbolic diffeomorphism on a 3-manifold, we show that any invariant foliation tangent to the center-unstable (or center-stable) bundle has no compact leaves.
Partially hyperbolic dynamics in dimension 3Jan 05 2015Dec 05 2016Partial hyperbolicity appeared in the sixties as a natural generaliza- tion of hyperbolicity. In the last 20 years in this area there has been great activity. Here we survey the state of the art in some topics, focusing especially in partial hyperbolicity ... More
A non-dynamically coherent example on ${\mathbb T}^3$Sep 02 2014In this paper we give the first example of a non-dynamically coherent partially hyperbolic diffeomorphism with one-dimensional center bundle. The existence of such an example had been an open question since 1975.
Some results on the integrability of the center bundle for partially hyperbolic diffeomorphismsSep 13 2006We prove, for f a partially hyperbolic diffeomorphism with center dimension one, two results about the integrability of its central bundle. On one side, we show that if the non wandering set of f is the whole manifold, and the manifold is 3 dimensional, ... More
Symmetry-preserving matchingsAug 06 2002In the literature, the matchings between spacetimes have been most of the times implicitly assumed to preserve some of the symmetries of the problem involved. But no definition for this kind of matching was given until recently. Loosely speaking, the ... More
The Age of the UniverseJan 29 1997In this article I review the main methods for determining the age of the Universe. I describe how to determine the age of the oldest known systems at z=0, the system of galactic globular clusters, using different techniques. I also describe how to date ... More
A Potential Correlation Between the Temperature of the Pacific Ocean and Data from Google Trends May Yield a Warning Sign for the Outbreak of ZikaJul 09 2016There has been a large number of reported cases of the occurrence of Zika in different countries in 2016 and it is necessary to develop an early warning system to initiate preventive campaigns against the disease. A potential early warning system based ... More
The kernel of chromatic quasisymmetric functions on graphs and nestohedraMar 23 2018Apr 05 2018We study the chromatic symmetric function on graphs, and show that its kernel is spanned by the modular relations. We generalise this result to the chromatic quasisymmetric function on nestohedra, a family of generalised permutahedra. We use this description ... More
The Epoch of Galaxy FormationOct 09 2001I present a biased review of when the epoch of formation of galaxies (both disks and ellipticals) maybe took place. I base my arguments in simple (mostly) analytic models that have been recently developed to reproduce most of the observed photometric, ... More
Ensemble equivalence for non-Bolztmannian distributionsMar 11 2004Sep 30 2005We discuss the possibility of using generalized canonical distributions, i.e. using other factors than $\exp(-\beta E)$, in order to compute the equilibrium properties of physical systems. It will be show that some other choices can, in certain cases, ... More
The Bessel-Plancherel theorem and applicationsNov 26 2012Let $G$ be a simple Lie Group with finite center, and let $K\subset G$ be a maximal compact subgroup. We say that $G$ is a Lie group of tube type if $G/K$ is a hermitian symmetric space of tube type. For such a Lie group $G$, we can find a parabolic subgroup ... More
The volume enclosed by an n-dimensional Lamé curveDec 03 2009We compute the volume of the body enclosed by the $n$-dimensional Lam\'e curve defined by $\sum_{i=1}^nx_i^b= E$.
On global models for isolated rotating axisymmetric charged bodies; uniqueness of the exterior fieldJul 14 2005A relatively recent study by Mars and Senovilla provided us with a uniqueness result for the exterior vacuum gravitational field generated by an isolated distribution of matter in axial rotation in equilibrium in General Relativity. The generalisation ... More
The value of the equation of state of dark energyMay 20 2003From recent CMB and Large Scale Structure observations the value of the equation of state of dark energy, assuming it to be constant in time, is constrained to be -1.3<w<-0.7 at the 95% confidence level: consistent with dark energy being a classical vacuum ... More
Asymptotic expansion for the models of nonlinear dispersive, dissipative, equationsNov 07 2003Considered herein are the family of nonlinear equations with both dispersive and dissipative homogeneous terms appended. Solutions of these equations that start with finite energia decay to zero as time goes to infinity. We present an asymptotic form ... More
The Design Principles of Konrad Zuse's Mechanical ComputersMar 08 2016Konrad Zuse built the Z1, a mechanical programmable computing machine, between 1935/36 and 1937/38. The Z1 was a binary floating-point computing device. The individual logical gates were constructed using metallic plates and interconnection rods. This ... More
The Keynesian Model in the General Theory: A TutorialAug 24 2017This small overview of the General Theory is the kind of summary I would have liked to have read, before embarking in a comprehensive study of the General Theory at the time I was a student. As shown here, the main ideas are quite simple and easy to visualize. ... More
Beyond the Standard Model of Physics with Astronomical ObservationsJul 09 2013There has been significant recent progress in observational cosmology. This, in turn, has provided an unprecedented picture of the early universe and its evolution. In this review I will present a (biased) view of how one can use these observational results ... More
Quantitative Prediction of Linear B-Cell EpitopesMar 07 2017In scientific literature, there are many programs that predict linear B-cell epitopes from a protein sequence. Each program generates multiple B-cell epitopes that can be individually studied. This paper defines a function called <C> that combines results ... More
Kalai orientations on matroid polytopesApr 15 2005Let P a polytope and let G(P) be the graph of P. Following Gil Kalai, we say that an acyclic orientation O of G(P) is good if, for every non-empty face F of P, the induced graph G(F) has exactly one sink. Gil Kalai gave a simple way to tell a simple polytope ... More
Tori with hyperbolic dynamics in 3-manifoldsNov 13 2010Let M be a closed orientable irreducible 3-manifold, and let f be a diffeomorphism over M. We call an embedded 2-torus T an Anosov torus if it is invariant and the induced action of f over \pi_1(T) is hyperbolic. We prove that only few irreducible 3-manifolds ... More
A survey on partially hyperbolic dynamicsSep 13 2006Sep 21 2006Some of the guiding problems in partially hyperbolic systems are the following: (1) Examples, (2) Properties of invariant foliations, (3) Accessibility, (4) Ergodicity, (5) Lyapunov exponents, (6) Integrability of central foliations, (7) Transitivity ... More
On the nonextensivity of the long range X-Y modelApr 01 2003May 19 2003It will be given analytical and numerical evidence supporting that the X-Y model yields an extensive, i.e. proportional to the number of degrees of freedom N, internal energy U for any value of the interaction range.
Analysis of an SEIR-SEI four-strain epidemic dengue model with primary and secondary infectionsJun 16 2014We propose an SEIR model for the populations and an SEI model for the vector to describe the transmission dynamics of a four-strain model with both primary and secondary dengue infections. In order to accomplish this, we propose and obtain an analytic ... More
Identification of 11 potential malaria vaccine candidates using BioinformaticsSep 29 2010In this paper, we suggested eleven protein targets to be used as possible vaccines against Plasmodium falciparum causative agent of almost two to three million deaths per year. A comprehensive analysis of protein target have been selected from the small ... More
A Tutorial Introduction to the Lambda CalculusMar 28 2015This paper is a concise and painless introduction to the $\lambda$-calculus. This formalism was developed by Alonzo Church as a tool for studying the mathematical properties of effectively computable functions. The formalism became popular and has provided ... More
The kernel of chromatic quasisymmetric functions on graphs and hypergraphic polytopesMar 23 2018Jul 09 2019We study the chromatic symmetric function on graphs, and show that its kernel is spanned by the modular relations. We generalize this result to the chromatic quasisymmetric function on hypergraphic polytopes, a family of generalized permutahedra. We use ... More
Evolution of event-by-event transverse-energy fluctuations over collision centrality in RHIC interactionsJan 10 2007Preliminary results are presented for two analyses of transverse energy (ET) production measured with the electromagnetic calorimeters of the Pioneering High Energy Nuclear Interaction Experiment (PHENIX), in nuclear interactions in Au+Au heavy-ion collisions ... More
Capital Redistribution Brings Wealth by Parrondo's ParadoxJun 20 2002We present new versions of the Parrondo's paradox by which a losing game can be turned into winning by including a mechanism that allows redistribution of the capital amongst an ensemble of players. This shows that, for this particular class of games, ... More
Extracting cosmological information from galaxy spectra and observations of high-redshift objectsNov 06 2000I review the statistical techniques needed to extract information about physical parameters of galaxies from their observed spectra. This is important given the sheer size of the next generation of large galaxy redshift surveys. Going to the opposite ... More
The Z1: Architecture and Algorithms of Konrad Zuse's First ComputerJun 07 2014This paper provides the first comprehensive description of the Z1, the mechanical computer built by the German inventor Konrad Zuse in Berlin from 1936 to 1938. The paper describes the main structural elements of the machine, the high-level architecture, ... More
The straight line, the catenary, the brachistochrone, the circle, and FermatJan 12 2014This paper shows that the well-known curve optimization problems which lead to the straight line, the catenary curve, the brachistochrone, and the circle, can all be handled using a unified formalism. Furthermore, from the general differential equation ... More
Identificación de nuevos medicamentos a través de métodos computacionalesNov 01 2010Resumen: El desarrollo de nuevos medicamentos es un problema complejo que carece de una soluci\'on \'unica y autom\'atica desde un punto de vista computacional, debido a la carencia de programas que permitan manejar grandes vol\'umenes de informaci\'on ... More
Deepest Neural NetworksJul 09 2017This paper shows that a long chain of perceptrons (that is, a multilayer perceptron, or MLP, with many hidden layers of width one) can be a universal classifier. The classification procedure is not necessarily computationally efficient, but the technique ... More
Logistic Regression as Soft Perceptron LearningAug 24 2017We comment on the fact that gradient ascent for logistic regression has a connection with the perceptron learning algorithm. Logistic learning is the "soft" variant of perceptron learning.
Uniqueness of SRB measures for transitive diffeomorphisms on surfacesMay 22 2010We give a description of ergodic components of SRB measures in terms of ergodic homoclinic classes associated to hyperbolic periodic points. For transitive surface diffeomorphisms, we prove that there exists at most one SRB measure.
Significant primordial star formation at redshifts z ~ 3-4Feb 20 2006Feb 27 2006Four recent observational results have challenged our understanding of high--redshift galaxies, as they require the presence of far more ultraviolet photons than should be emitted by normal stellar populations. First, there is significant ultraviolet ... More
A Structural Parameter for High Tc Superconductivity from an Octahedral Moebius Strip in RBaCuO:123 type PerovskitesAug 01 2003An index for the characterisation of the Perovskite type Superconductors is introduced. The index, denominated as Structural Parameter of High Tc Superconductivity (PESATc from its name in Spanish), is calculated using a Moebius Orbital defined as the ... More
Ages of globular clusters: breaking the age-distance degeneracy with the luminosity functionMar 14 1996We extend our previous method to determine globular cluster ages using the luminosity function (Jimenez \& Padoan 1996). We show that the luminosity function depends on both age and distance modulus and that it is possible to distinguish between the two. ... More
Core-biased random walks in complex networksSep 22 2017A simple strategy to explore a network is to use a random-walk where the walker jumps from one node to an adjacent node at random. It is known that biasing the random jump, the walker can explore every walk of the same length with equal probability, this ... More
On the Degrees-of-Freedom of the K-User Gaussian Interference ChannelJan 13 2009The degrees-of-freedom of a K-user Gaussian interference channel (GIFC) has been defined to be the multiple of (1/2)log_2(P) at which the maximum sum of achievable rates grows with increasing P. In this paper, we establish that the degrees-of-freedom ... More
Quantifying Reticulation in Phylogenetic Complexes Using HomologyNov 04 2015Reticulate evolutionary processes result in phylogenetic histories that cannot be modeled using a tree topology. Here, we apply methods from topological data analysis to molecular sequence data with reticulations. Using a simple example, we demonstrate ... More
Strand-Based Approach to Patch Security ProtocolsAug 08 2013In this paper, we introduce a mechanism that aims to speed up the development cycle of security protocols, by adding automated aid for diagnosis and repair. Our mechanism relies on existing verification tools analyzing intermediate protocols and synthesizing ... More
Dilaton tadpoles and D-brane interactions in compact spacesJul 19 2002Dec 02 2002We analyse some physical consequences when supersymmetry is broken by a set of D-branes and/or orientifold planes in Type II string theories. Generically, there are global dilaton tadpoles at the disk level when the transverse space is compact. By taking ... More
Insights into the robustness of control point configurations for homography and planar pose estimationMar 08 2018Jan 09 2019In this paper, we investigate the influence of the spatial configuration of a number of $n \geq 4$ control points on the accuracy and robustness of space resection methods, e.g. used by a fiducial marker for pose estimation. We find robust configurations ... More
Dynamic Markers: UAV landing proof of conceptSep 14 2017Jan 09 2019In this paper, we introduce a dynamic fiducial marker which can change its appearance according to the spatiotemporal requirements of the visual perception task of a mobile robot using a camera as the sensor. We present a control scheme to dynamically ... More
The noisy voter model under the influence of contrariansJul 09 2018The influence of contrarians on the noisy voter model is studied at the mean-field level. The noisy voter model is a variant of the voter model where agents can adopt two opinions, optimistic or pessimistic, and can change them by means of an imitation ... More
Pricing of Warrants with Stock Price Dependent Threshold ConditionsMar 17 2015Warrants with stock price dependent threshold conditions give the right to buy specially issued stocks, if the performance of the stock price satisfies some requirements. Existence of these derivatives changes the price process of the underlying. We show ... More
A new method to determine Globular Cluster agesFeb 02 1996We present a new method to compute stellar ages in Globular Clusters (GC) that is ten times more precise than the traditional isochrone fitting procedure. The method relies on accurate stellar evolutionary tracks and on photometry for GCs complete down ... More
A Monte Carlo Method for the Numerical Simulation of Tsallis StatisticsNov 04 1999We present a new method devised to overcome the intrinsic difficulties associated to the numerical simulations of the Tsallis statistics. We use a standard Metropolis Monte Carlo algorithm at a fictitious temperature T', combined with a numerical integration ... More
Smolyak's algorithm: A powerful black box for the acceleration of scientific computationsMar 26 2017Apr 08 2017We provide a general discussion of Smolyak's algorithm for the acceleration of scientific computations. The algorithm first appeared in Smolyak's work on multidimensional integration and interpolation. Since then, it has been generalized in multiple directions ... More
(Re)constructing DimensionsDec 12 2002Jan 16 2003Compactifying a higher-dimensional theory defined in R^{1,3+n} on an n-dimensional manifold {\cal M} results in a spectrum of four-dimensional (bosonic) fields with masses m^2_i = \lambda_i, where - \lambda_i are the eigenvalues of the Laplacian on the ... More
Smolyak's algorithm: A powerful black box for the acceleration of scientific computationsMar 26 2017Jul 16 2018We provide a general discussion of Smolyak's algorithm for the acceleration of scientific computations. The algorithm first appeared in Smolyak's work on multidimensional integration and interpolation. Since then, it has been generalized in multiple directions ... More
Order parameter expansion study of synchronous firing induced by quenched noise in the active rotator modelJul 27 2010We use a recently developed order parameter expansion method to study the transition to synchronous firing occuring in a system of coupled active rotators under the exclusive presence of quenched noise. The method predicts correctly the existence of a ... More
Implications for Primordial Non-Gaussianity (f_NL) from weak lensing masses of high-z galaxy clustersSep 02 2009The recent weak lensing measurement of the dark matter mass of the high-redshift galaxy cluster XMMUJ2235.3-2557 of (8.5 +- 1.7) x 10^{14} Msun at z=1.4, indicates that, if the cluster is assumed to be the result of the collapse of dark matter in a primordial ... More
Constraining spacetime noncommutativity with primordial nucleosynthesisJan 27 2009Apr 01 2009We discuss a constraint on the scale $\Lambda_{\rm NC}$ of noncommutative (NC) gauge field theory arising from consideration of the big bang nucleosynthesis (BBN) of light elements. The propagation of neutrinos in the NC background described by an antisymmetric ... More
Ensembles based on the Rich-Club and how to use them to build soft-communitiesApr 21 2015Ensembles of networks are used as null-models to discriminate network structures. We present an efficient algorithm, based on the maximal entropy method to generate network ensembles defined by the degree sequence and the rich-club coefficient. The method ... More
On the Determination of Elastic and Inelastic Nuclear Observables from Lattice QCDNov 23 2013Dec 15 2013One of the overarching goals of nuclear physics is to rigorously compute properties of hadronic systems directly from the fundamental theory of the strong interaction, Quantum Chromodynamics (QCD). Currently, lattice QCD (LQCD) provides the only reliable ... More
Topological bifurcations in a model society of reasonable contrariansAug 19 2013People are often divided into conformists and contrarians, the former tending to align to the majority opinion in their neighborhood and the latter tending to disagree with that majority. In practice, however, the contrarian tendency is rarely followed ... More
Phase Transitions of Cellular AutomataSep 15 2014We explore some aspects of phase transitions in cellular automata. We start recalling the standard formulation of statistical mechanics of discrete systems (Ising model), illustrating the Monte Carlo approach as Markov chains and stochastic processes. ... More
Reconciling the GRB rate and star formation historiesMar 20 2013Jun 12 2013While there are numerous indications that GRBs arise from the death of massive stars, the GRB rate does not follow the global cosmic star formation rate and, within their hosts, GRBs are more concentrated in regions of very high star formation. We explain ... More
Malware Detection Module using Machine Learning Algorithms to Assist in Centralized Security in Enterprise NetworksFeb 08 2012Malicious software is abundant in a world of innumerable computer users, who are constantly faced with these threats from various sources like the internet, local networks and portable drives. Malware is potentially low to high risk and can cause systems ... More
Constraining noncommutative field theories with holographySep 15 2010Jan 19 2011An important window to quantum gravity phenomena in low energy noncommutative (NC) quantum field theories (QFTs) gets represented by a specific form of UV/IR mixing. Yet another important window to quantum gravity, a holography, manifests itself in effective ... More
Phase transitions induced by microscopic disorder: a study based on the order parameter expansionMar 04 2010Based on the order parameter expansion, we present an approximate method which allows us to reduce large systems of coupled differential equations with diverse parameters to three equations: one for the global, mean field, variable and two which describe ... More
Beyond the rich-club: Properties of networks related to the better connected nodesOct 29 2018Many of the structural characteristics of a network depend on the connectivity with and within the hubs. These dependencies can be related to the degree of a node and the number of links that a node shares with nodes of higher degree. In here we revise ... More
Recent results from the cosmic ray program of the NA61/SHINE experimentOct 01 2018NA61/SHINE is a fixed target experiment designed to study hadron-proton, hadron-nucleus and nucleus-nucleus interactions at the CERN Super-Proton-Synchrotron. In this paper we summarize the results from pion-carbon collisions recorded at beam momenta ... More
El Triangulo de Platon y El Factor Gnomonico: Una aplicacion a los oraculos de HerodotoMay 24 2013A modification to the gnomonic factor using the concept of triangle of Plato is presented. With the aid of the platonic gnomonic factor (fgp) as we called it, we find that the oracles mentioned by Herodotus in his History, Dodona in Greece and Ammon in ... More
Topological Data Analysis of Single-cell Hi-C Contact MapsDec 04 2018In this article, we show how the recent statistical techniques developed in Topological Data Analysis for the Mapper algorithm can be extended and leveraged to formally define and statistically quantify the presence of topological structures coming from ... More
Diagonal bases in Orlik-Solomon type algebrasJan 18 2002Jul 09 2003To encode an important property of the "no broken circuit bases" of the Orlik-Solomon-Terao algebras, Andras Szenes has introduced a particular type of bases, the so called "diagonal basis". We prove that this definition extends naturally to a large class ... More
Flooding in urban drainage systems: Coupling hyperbolic conservation laws for sewer systems and surface flowFeb 18 2014In this paper we propose a model for a sewer network coupled to surface flow and investigate it numerically. In particular, we present a new model for the manholes in storm sewer systems. It is derived using the balance of the total energy in the complete ... More
Isometric actions of simple groups and transverse structures: The integrable normal caseMar 09 2010For actions with a dense orbit of a connected noncompact simple Lie group $G$, we obtain some global rigidity results when the actions preserve certain geometric structures. In particular, we prove that for a $G$-action to be equivalent to one on a space ... More
Separately Radial and Radial Toeplitz Operators on the Unit Ball and Representation TheorySep 23 2015Jan 26 2016We study Toeplitz operators with separately radial and radial symbols on the weighted Bergman spaces on the unit ball. The unitary equivalence of such operators with multiplication operators on $\ell^2$ spaces was previously obtained by analytic methods ... More
About the decomposition of pricing formulas under stochastic volatility modelsMar 27 2015We obtain a decomposition of the call option price for a very general stochastic volatility diffusion model extending the decomposition obtained by E. Al\`os in [2] for the Heston model. We realize that a new term arises when the stock price does not ... More
A nonlinear discrete-velocity relaxation model for traffic flowOct 17 2017We derive a nonlinear 2-equation discrete-velocity model for traffic flow from a continuous kinetic model. The model converges to scalar Lighthill-Whitham type equations in the relaxation limit for all ranges of traffic data. Moreover, the model has an ... More
Arithmeticity of totally geodesic Lie foliations with locally symmetric leavesJan 08 2007R. Zimmer proved that, on a compact manifold, a foliation with a dense leaf, a suitable leafwise Riemannian symmetric metric and a transverse Lie structure has arithmetic holonomy group. In this work we improve such result for totally geodesic foliations ... More
Ensemble equivalence for non-extensive thermostatisticsSep 07 2001We compute the internal energy of different Ising type models, both long-range and short-range, under Tsallis statistics using the microcanonical and the canonical ensembles and we discuss under which conditions both ensembles give equivalent results. ... More
A Saito criterion for holonomic divisorsNov 28 2017We prove a variant of Saito's freeness criterion for holonomic divisors. It applies in particular to complex hyperplane arrangements.
Collider Bounds on Pseudoscalars Coupling to Gauge BosonsOct 13 2005Nov 21 2005We bound the coupling of pseudo-scalar particles to Tr G^G_{QCD} using (the lack of) monojet plus missing E_T events at the Tevatron, and estimate the bounds obtainable from LHC. In addition, we revisit the bounds on the coupling to F^F_{EM} from e^+e^- ... More
Synchronization universality classes and stability of smooth, coupled map latticesJul 08 2005Nov 18 2005We study two problems related to spatially extended systems: the dynamical stability and the universality classes of the replica synchronization transition. We use a simple model of one dimensional coupled map lattices and show that chaotic behavior implies ... More
Parrondo's games and the zipping algorithmFeb 20 2004We study the relation between the discrete--time version of the flashing ratchet known as Parrondo's games and a compression technique used very recently with thermal ratchets for evaluating the transfer of information -- negentropy -- between the Brownian ... More
A New structural parameter for Perovskite type compounds and its application to 'Stripe Phases'Aug 01 2003Aug 07 2003A new parameter named PESATc (Parametro Estructural de los Superconductores de Alta Temperatura critica) is presented and used to discuss an aproach to the 'Stripe Phases' in (La,Ca)MnO3 superconductors. The PESATc parameter is based on the superposition ... More
D=4, N=1 orientifolds with vector structureJul 11 2000Aug 22 2000We construct compact type IIB orientifolds with discrete groups Z_4, Z_6, Z_6', Z_8, Z_12 and Z_12'. These models are N=1 supersymmetric in D=4 and have vector structure. The possibility of having vector structure in Z_N orientifolds with even N arises ... More
The Back Reaction of Gravitational Perturbations and Applications in CosmologySep 18 1997Sep 20 1997We study the back reaction of cosmological perturbations on the evolution of the universe. The object usually employed to describe the back reaction of perturbations is called the effective energy-momentum tensor (EEMT) of cosmological perturbations. ... More
The full Fisher matrix for galaxy surveysAug 27 2011May 25 2012Starting from the Fisher matrix for counts in cells, I derive the full Fisher matrix for surveys of multiple tracers of large-scale structure. The key assumption is that the inverse of the covariance of the galaxy counts is given by the naive matrix inverse ... More
On the role of GRBs on life extinction in the UniverseSep 08 2014Nov 13 2014As a copious source of gamma-rays, a nearby Galactic Gamma-Ray Burst (GRB) can be a threat to life. Using recent determinations of the rate of GRBs, their luminosity function and properties of their host galaxies, we estimate the probability that a life-threatening ... More
Two-Nucleon Systems in a Finite VolumeSep 30 2013Nov 06 2013I present the formalism and methodology for determining the nucleon-nucleon scattering parameters from the finite volume spectra obtained from lattice quantum chromodynamics calculations. Using the recently derived energy quantization conditions and the ... More
The role of virtual photons in quantum tunnelingDec 14 2018Quantum tunneling, a phenomenon which has no counterpart in classical physics, is the quantum-mechanical process by which a microscopic particle can transition through a potential barrier even when the energy of the incident particle is lower than the ... More
Bulk-Edge correspondence of entanglement spectrum in 2D spin ground statesAug 16 2012Dec 04 2012General local spin $S$ ground states, described by a Valence Bond Solid (VBS) on a two dimensional lattice are studied. The norm of these ground states is mapped to a classical O(3) model on the same lattice. Using this quantum-to-classical mapping we ... More
Quadratic Orlik-Solomon algebras of graphic matroidsJun 15 2001Jan 08 2003In this note we introduce a sufficient condition for the Orlik-Solomon algebra associated to a matroid M to be l-adic and we prove that this condition is necessary when M is binary (in particular graphic). Moreover, this result cannot be extended to the ... More
Groebner and diagonal bases in Orlik-Solomon type algebrasJun 11 2001Oct 07 2003The Orlik-Solomon algebra of a matroid M is the quotient of the exterior algebra on the points by the ideal I(M) generated by the boundaries of the circuits of the matroid. There is an isomorphism between the Orlik-Solomon algebra of a complex matroid ... More
Hipparcos and the Age of the Galactic DiscSep 06 1997Sep 22 1997We have used the Hipparcos satellite colour magnitude diagram to determine the age of the Galactic disc. We first measure the metallicities of Hipparcos giants using DDO photometry (H{\o}g & Flynn 1997). With accurate metallicities and distances we compute ... More
Kinetic layers and coupling conditions for nonlinear scalar equations on networksJan 01 2018We consider a kinetic relaxation model and an associated macroscopic scalar nonlinear hyperbolic equation on a network. Coupling conditions for the macroscopic equations are derived from the kinetic coupling conditions via an asymptotic analysis near ... More
Distributed computing applied applied to the identification of new drugsDec 14 2010This work emphasizes the assets of implementing the distributed computing for the intensive use in computational science devoted to the search of new medicines that could be applied in public healthy problems.
MISO: An intermediate language to express parallel and dependable programsAug 22 2016One way to write fast programs is to explore the potential parallelism and take advantage of the high number of cores available in microprocessors. This can be achieved by manually specifying which code executes on which thread, by using compiler parallelization ... More
Generalized Lyapunov exponents of the random harmonic oscillator: cumulant expansion approachNov 24 2011The cumulant expansion is used to estimate generalized Lyapunov exponents of the random-frequency harmonic oscillator. Three stochastic processes are considered: Gaussian white noise, Ornstein-Uhlenbeck, and Poisson shot noise. In some cases, nontrivial ... More