Results for "Javier Gonzalez-Jimenez"

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Geometric-based Line Segment Tracking for HDR Stereo SequencesSep 25 2018In this work, we propose a purely geometrical approach for the robust matching of line segments for challenging stereo streams with severe illumination changes or High Dynamic Range (HDR) environments. To that purpose, we exploit the univocal nature of ... More
Learning-based Image Enhancement for Visual Odometry in Challenging HDR EnvironmentsJul 05 2017Apr 09 2018One of the main open challenges in visual odometry (VO) is the robustness to difficult illumination conditions or high dynamic range (HDR) environments. The main difficulties in these situations come from both the limitations of the sensors and the inability ... More
Intrinsic Calibration of Depth Cameras for Mobile Robots using a Radial Laser ScannerJul 03 2019Depth cameras, typically in RGB-D configurations, are common devices in mobile robotic platforms given their appealing features: high frequency and resolution, low price and power requirements, among others. These sensors may come with significant, non-linear ... More
Computers and turbulenceFeb 22 2019This paper briefly reviews the influence that the rapid evolution of computer power in the last decades has had on turbulence research. It is argued that it can be divided into three stages. In the earliest (`heroic') one, simulations were expensive and ... More
Computers and turbulenceFeb 22 2019Jul 11 2019This paper briefly reviews the influence that the rapid evolution of computer power in the last decades has had on turbulence research. It is argued that it can be divided into three stages. In the earliest (`heroic') one, simulations were expensive and ... More
Automatic Multi-Sensor Extrinsic Calibration for Mobile RobotsJun 11 2019In order to fuse measurements from multiple sensors mounted on a mobile robot, it is needed to express them in a common reference system through their relative spatial transformations. In this paper, we present a method to estimate the full 6DoF extrinsic ... More
Direct numerical simulation of the very large anisotropic scales in a turbulent channelSep 09 2013Over the last decades the knowledge on the small scales of turbulent wall flows has experienced a significant advance, especially in the near-wall region where the highest production of turbulent energy and the maximum turbulence intensity occur. The ... More
Characteristics of scalar dispersion in turbulent-channel flowSep 09 2013The dispersion of a passive scalar by wall turbulence, in the limit of infinite Peclet number, is analyzed using frozen velocity fields from the DNS by our group. The Lagrangian trajectories of fluid particles in those fields are integrated and used to ... More
On smooth extensions of vector-valued functions defined on closed subsets of Banach spacesDec 26 2011Let $X$ and $Z$ be Banach spaces, $A$ a closed subset of $X$ and a mapping $f:A \to Z$. We give necessary and sufficient conditions to obtain a $C^1$ smooth mapping $F:X \to Z$ such that $F_{\mid_A}=f$, when either (i) $X$ and $Z$ are Hilbert spaces and ... More
Cropping Euler factors of modular L-functionsFeb 23 2010Mar 29 2010According to the Birch and Swinnerton-Dyer conjectures, if A/Q is an abelian variety then its L-function must capture substantial part of the arithmetic properties of A. The smallest number field L where A has all its endomorphisms defined must also have ... More
On some problems on smooth approximation and smooth extension of Lipschitz functions on Banach-Finsler ManifoldsDec 21 2010Dec 25 2010Let us consider a Riemannian manifold $M$ (either separable or non-separable). We prove that, for every $\epsilon>0$, every Lipschitz function $f:M\rightarrow\mathbb R$ can be uniformly approximated by a Lipschitz, $C^1$-smooth function $g$ with $\Lip(g)\le ... More
On the torsion of rational elliptic curves over quartic fieldsJun 02 2016Let E be an elliptic curve defined over Q and let G = E(Q)_tors be the associated torsion subgroup. We study, for a given G, which possible groups G <= H could appear such that H=E(K)_tors, for [K:Q]=4 and H is one of the possible torsion structures that ... More
On the ubiquity of trivial torsion on elliptic curvesFeb 03 2010The purpose of this paper is to give a "down--to--earth" proof of the well--known fact that a randomly chosen elliptic curve over the rationals is most likely to have trivial torsion.
Electron dynamics inside a vacuum tube diode through linear differential equationsMar 08 2013In this paper we analyze the motion of charged particles in a vacuum tube diode by solving linear differential equations. Our analysis is based on expressing the volume charge density as a function of the current density and coordinates only, while in ... More
Finiteness results for modular curves of genus at least 2Nov 26 2002Dec 22 2003A curve X over the field Q of rational numbers is modular if it is dominated by X_1(N) for some N; if in addition the image of its jacobian in J_1(N) is contained in the new subvariety of J_1(N), then X is called a new modular curve. We prove that for ... More
Torsion of rational elliptic curves over cubic fieldsNov 13 2014Apr 07 2015Let E be an elliptic curve defined over Q. We study the relationship between the torsion subgroup E(Q)_tors and the torsion subgroup E(K)_tors, where K is a cubic number field. In particular, We study the number of cubic number fields K such that E(Q)_tors\neq ... More
Wiggly cosmic strings accrete dark energyJun 29 2005This paper deals with a study of the cylindrically symmetric accretion of dark energy with equation of state $p=w\rho$ onto wiggly straight cosmic strings. We have obtained that when $w>-1$ the linear energy density in the string core gradually increases ... More
Validating WordNet Meronymy Relations using Adimen-SUMOMay 20 2018In this paper, we report on the practical application of a novel approach for validating the knowledge of WordNet using Adimen-SUMO. In particular, this paper focuses on cross-checking the WordNet meronymy relations against the knowledge encoded in Adimen-SUMO. ... More
Relation between halo spin and cosmic web filaments at z~3Jun 14 2016We investigate the spin evolution of dark matter haloes and their dependence on the number of connected filaments from the cosmic web at high redshift (spin-filament relation hereafter). To this purpose, we have simulated $5000$ haloes in the mass range ... More
3D Well-composed Polyhedral ComplexesMar 12 2014A binary three-dimensional (3D) image $I$ is well-composed if the boundary surface of its continuous analog is a 2D manifold. Since 3D images are not often well-composed, there are several voxel-based methods ("repairing" algorithms) for turning them ... More
Characterization of a Banach-Finsler manifold in terms of the algebras of smooth functionsAug 26 2011In this note we give sufficient conditions to ensure that the weak Finsler structure of a complete $C^k$ Finsler manifold $M$ is determined by the normed algebra $C_b^k(M)$ of all real-valued, bounded and $C^k$ smooth functions with bounded derivative ... More
Chain Homotopies for Object Topological RepresentationsMay 18 2011May 20 2011This paper presents a set of tools to compute topological information of simplicial complexes, tools that are applicable to extract topological information from digital pictures. A simplicial complex is encoded in a (non-unique) algebraic-topological ... More
Cubical Cohomology Ring of 3D PhotographsMay 20 2011Cohomology and cohomology ring of three-dimensional (3D) objects are topological invariants that characterize holes and their relations. Cohomology ring has been traditionally computed on simplicial complexes. Nevertheless, cubical complexes deal directly ... More
Applying the Closed World Assumption to SUMO-based OntologiesAug 14 2018In commonsense knowledge representation, the Open World Assumption is adopted as a general standard strategy for the design, construction and use of ontologies, e.g. in OWL. This strategy limits the inferencing capabilities of any system using these ontologies ... More
Joint Synchronization, Phase Noise and Compressive Channel Estimation in Hybrid Frequency-Selective mmWave MIMO SystemsJun 05 2019The large beamforming gain used to operate at millimeter wave (mmWave) frequencies requires obtaining channel information to configure hybrid antenna arrays. Previously proposed wideband channel estimation strategies, however, assume perfect time-frequency ... More
Active Multi-Information Source Bayesian QuadratureMar 27 2019Bayesian quadrature (BQ) is a sample-efficient probabilistic numerical method to solve integrals of expensive-to-evaluate black-box functions, yet so far,active BQ learning schemes focus merely on the integrand itself as information source, and do not ... More
A Matching Game for Data Trading in Operator-Supervised User-Provided NetworksFeb 16 2016Oct 26 2016In this paper, we consider a recent cellular network connection paradigm, known as user-provided network (UPN), where users share their connectivity and act as an access point for other users. To incentivize user participation in this network, we allow ... More
A Matching Game for Data Trading in Operator-Supervised User-Provided NetworksFeb 16 2016In this paper, we consider a recent cellular network connection paradigm, known as user-provided network (UPN), where users share their connectivity and act as an access point for other users. To incentivize user participation in this network, we allow ... More
Synchronization of fluctuating chaotic networksOct 20 2016We consider the synchronization of identical chaotic units connected through time-delayed interactions when the interaction network fluctuates. A random alternation of network structures can, in fact, enhance the synchronizability. We focus on fluctuating ... More
Right triangles with algebraic sides and elliptic curves over number fieldsMar 26 2009Given any positive integer n, we prove the existence of infinitely many right triangles with area n and side lengths in certain number fields. This generalizes the famous congruent number problem. The proof allows the explicit construction of these triangles; ... More
An Infinite Family of Self-consistent Models for Axisymmetric Flat GalaxiesJun 26 2008We present the formulation of a new infinite family of self-consistent stellar models, designed to describe axisymmetric flat galaxies. The corresponding density-potential pair is obtained as a superposition of members belonging to the generalized Kalnajs ... More
Deformations of canonical triple coversNov 21 2015In this paper, we show that if $X$ is a smooth variety of general type of dimension $m \geq 3$ for which the canonical map induces a triple cover onto $Y$, where $Y$ is a projective bundle over $\mathbf P^1$ or onto a projective space or onto a quadric ... More
Analytical Models of the Performance of C-V2X Mode 4 Vehicular CommunicationsJul 17 2018Dec 21 2018The C-V2X or LTE-V standard has been designed to support V2X (Vehicle to Everything) communications. The standard is an evolution of LTE, and it has been published by the 3GPP in Release 14. This new standard introduces the C-V2X or LTE-V Mode 4 that ... More
Channel Tracking and Hybrid Precoding for Wideband Hybrid Millimeter Wave MIMO SystemsMay 10 2019A major source of difficulty when operating with large arrays at mmWave frequencies is to estimate the wideband channel, since the use of hybrid architectures acts as a compression stage for the received signal. Moreover, the channel has to be tracked ... More
Hybrid precoding and combining for frequency-selective mmWave MIMO Systems with per-antenna power constraintsDec 06 2018Feb 01 2019Configuring hybrid precoders and combiners is a major challenge to deploy practical mmWave communication systems. Prior work addresses the problem of designing hybrid precoders and combiner, yet focusing on finding solutions under a total transmit power ... More
A Novel Collaborative Cognitive Dynamic Network ArchitectureOct 10 2016Increasing mobile data demands in current cellular networks and proliferation of advanced handheld devices have given rise to a new generation of dynamic network architectures (DNAs). In a DNA, users share their connectivities and act as access points ... More
K3 double structures on Enriques surfaces and their smoothingsApr 28 2006Aug 27 2006Let $Y$ be a smooth Enriques surface. A $K3$ carpet on $Y$ is a locally Cohen-Macaulay double structure on $Y$ with the same invariants as a smooth $K3$ surface (i.e., regular and with trivial canonical sheaf). The surface $Y$ possesses an \'etale $K3$ ... More
The occupation of a box as a toy model for the seismic cycle of a faultFeb 09 2005May 16 2007We illustrate how a simple statistical model can describe the quasiperiodic occurrence of large earthquakes. The model idealizes the loading of elastic energy in a seismic fault by the stochastic filling of a box. The emptying of the box after it is full ... More
Deformations of canonical double coversNov 21 2015In this paper, we show that if $X$ is a smooth variety of general type of dimension $m \geq 2$, for which its canonical map induces a double cover onto $Y$, where $Y$ is a projective bundle over $\mathbf P^1$, or onto a projective space or onto a quadric ... More
The Dynamics of Protest Recruitment through an Online NetworkNov 23 2011Dec 23 2011The recent wave of mobilizations in the Arab world and across Western countries has generated much discussion on how digital media is connected to the diffusion of protests. We examine that connection using data from the surge of mobilizations that took ... More
Meta-Surrogate Benchmarking for Hyperparameter OptimizationMay 30 2019Despite the recent progress in hyperparameter optimization (HPO), available benchmarks that resemble real-world scenarios consist of a few and very large problem instances that are expensive to solve. This blocks researchers and practitioners not only ... More
Loginson: a transform and load system for very large scale log analysis in large IT infrastructuresMar 07 2017Nowadays, most systems and applications produce log records that are useful for security and monitoring purposes such as debugging programming errors, checking system status, and detecting configuration problems or even attacks. To this end, a log repository ... More
Automatic Discovery of Privacy-Utility Pareto FrontsMay 26 2019Differential privacy is a mathematical framework for privacy-preserving data analysis. Changing the hyperparameters of a differentially private algorithm allows one to trade off privacy and utility in a principled way. Quantifying this trade-off in advance ... More
6G: The Next FrontierJan 10 2019May 16 2019The current development of 5G networks represents a breakthrough in the design of communication networks, for its ability to provide a single platform enabling a variety of different services, from enhanced mobile broadband communications, automated driving, ... More
Performance improvement of refractometric sensors through hybrid plasmonic-Fano resonancesMar 31 2019In this paper, we present a plasmonic refractometric sensor that works under normal incidence; allowing its integration on a fiber tip. The sensor's material and geometry exploit the large scattering cross-section given by high-contrast of the index of ... More
An X-ray view of 82 LINERs with Chandra and XMM-Newton dataMay 18 2009We present the results of an homogeneous X-ray analysis for 82 nearby LINERs selected from the catalogue of Carrillo et al. (1999). All sources have available Chandra (68 sources) and/or XMM-Newton (55 sources) observations. This is the largest sample ... More
A class of Hamilton-Jacobi equations on Banach-Finsler manifoldsJul 10 2014Dec 02 2014The concept of subdifferentiability is studied in the context of $C^1$ Finsler manifolds (modeled on a Banach space with a Lipschitz $C^1$ bump function). A class of Hamilton-Jacobi equations defined on $C^1$ Finsler manifolds is studied and several results ... More
Charged-current inclusive neutrino cross sections in the SuperScaling model including quasielastic, pion production and meson-exchange contributionsJun 02 2015Charged current inclusive neutrino-nucleus cross sections are evaluated using the superscaling model for quasielastic scattering and its extension to the pion production region. The contribution of two-particle-two-hole vector meson-exchange current excitations ... More
Superscaling in electron-nucleus scattering and its link to CC and NC QE neutrino-nucleus scatteringMar 26 2013The superscaling approach (SuSA) to neutrino-nucleus scattering, based on the assumed universality of the scaling function for electromagnetic and weak interactions, is reviewed. The predictions of the SuSA model for bot CC and NC differential and total ... More
A new topological entropy-based approach for measuring similarities among piecewise linear functionsDec 23 2015Dec 26 2015In this paper we present a novel methodology based on a topological entropy, the so-called persistent entropy, for addressing the comparison between discrete piecewise linear functions. The comparison is certified by the stability theorem for persistent ... More
Computing Small 1-Homological Models for Commutative Differential Graded AlgebrasOct 31 2001We use homological perturbation machinery specific for the algebra category [P. Real. Homological Perturbation Theory and Associativity. Homology, Homotopy and Applications vol. 2, n. 5 (2000) 51-88] to give an algorithm for computing the differential ... More
Optimal fluxes and Reynolds stressesJun 07 2016It is remarked that fluxes in conservation laws, such as the Reynolds stresses in the momentum equation of turbulent shear flows, or the spectral energy flux in isotropic turbulence, are only defined up to an arbitrary solenoidal field. While this is ... More
Machine-aided turbulence theoryJun 16 2018Aug 13 2018The question of whether significant sub-volumes of a turbulent flow can be identified by automatic means, independently of a-priori assumptions, is addressed using the example of two-dimensional decaying turbulence. Significance is defined as influence ... More
Coherent structures in wall-bounded turbulenceOct 20 2017Feb 24 2018This article discusses the description of wall-bounded turbulence as a deterministic high-dimensional dynamical system of interacting coherent structures, defined as eddies with enough internal dynamics to behave relatively autonomously from any remaining ... More
A Minimalist Model of Characteristic EarthquakesDec 17 2001In a spirit akin to the sandpile model of self-organized criticality, we present a simple statistical model of the cellular-automaton type which produces an avalanche spectrum similar to the characteristic-earthquake behavior of some seismic faults. This ... More
QED description of Raman scattering from molecules in plasmonic cavitiesSep 13 2015Sep 16 2016Plasmon-enhanced Raman scattering can push single-molecule vibrational spectroscopy beyond a regime addressable by classical electrodynamics. We employ a quantum electrodynamics (QED) description of the coherent interaction of plasmons and molecular vibrations ... More
The ETS challenges: a machine learning approach to the evaluation of simulated financial time series for improving generation processesNov 19 2018This paper presents an evaluation framework that attempts to quantify the "degree of realism" of simulated financial time series, whatever the simulation method could be, with the aim of discover unknown characteristics that are not being properly reproduced ... More
Generating virtual scenarios of multivariate financial data for quantitative trading applicationsFeb 06 2018In this paper, we present a novel approach to the generation of virtual scenarios of multivariate financial data of arbitrary length and composition of assets. With this approach, decades of realistic time-synchronized data can be simulated for a large ... More
Testable Axion-Like Particles In The Minimal Linear σ ModelJul 23 2018Axion and axion-like particle models are typically affected by a strong fine-tuning problem in conceiving the electroweak and the Peccei-Quinn breaking scales. Within the context of the Minimal Linear {\sigma} Model, axion-like particle constructions ... More
A Robust Dynamic Edge Network Architecture for the Internet-of-ThingsOct 13 2017A massive number of devices are expected to fulfill the missions of sensing, processing and control in cyber-physical Internet-of-Things (IoT) systems with new applications and connectivity requirements. In this context, scarce spectrum resources must ... More
A way to synchronize models with seismic faults for earthquake forecasting: Insights from a simple stochastic modelJul 21 2005Feb 13 2006Numerical models are starting to be used for determining the future behaviour of seismic faults and fault networks. Their final goal would be to forecast future large earthquakes. In order to use them for this task, it is necessary to synchronize each ... More
On the origin of the gamma-ray emission from Omega Centauri: Milisecond pulsars and dark matter annihilationJul 15 2019We explore two possible scenarios to explain the observed gamma-ray emission associated with the atypical globular cluster Omega-Centauri: emission from millisecond pulsars (MSP) and dark matter (DM) annihilation. In the first case the total number of ... More
Capacity Analysis of IEEE 802.11ah WLANs for M2M CommunicationsOct 25 2013Dec 28 2013Focusing on the increasing market of the sensors and actuators networks, the IEEE 802.11ah Task Group is currently working on the standardization of a new amendment. This new amendment will operate at the sub-1GHz band, ensure transmission ranges up to ... More
Forecasting characteristic earthquakes in a minimalist modelMay 14 2003Jul 30 2003Using error diagrams, we quantify the forecasting of characteristic-earthquake occurrence in a recently introduced minimalist model. Initially we connect the earthquake alarm at a fixed time after the ocurrence of a characteristic event. The evaluation ... More
Towards an accurate determination of the age of the UniverseOct 20 1998Oct 21 1998In the past 40 years a considerable effort has been focused in determining the age of the Universe at zero redshift using several stellar clocks. In this review I will describe the best theoretical methods to determine the age of the oldest Galactic Globular ... More
Setting the stellar evolution clock for intermediate age populationsJun 04 1999In this invited talk I show how the reddest and rarest galaxies at high redshift ($z \simeq 1.5$) can be used to set the stellar evolution clock. I argue that one can confidently compute the collapse redshift of these objects. This yields to a high collapse ... More
Quantitative Evaluation of the Effects of Positional versus Orientational Disorder on the Scattering of Acoustic Phonons in Disordered MatterOct 26 2006The phonon scattering processes on the three solid phases of ethanol are investigated by means of thermal conductivity, light and neutron scattering measurements as well as molecular dynamics simulations on single-crystalline models for the two crystalline ... More
Evidence of thermal transport anisotropy in stable glasses of vapour deposited organic moleculesOct 27 2017Vapour-deposited organic glasses are currently in use in many optoelectronic devices. Their operation temperature is limited by the glass transition temperature of the organic layers and thermal management strategies become increasingly important to improve ... More
PL-SLAM: a Stereo SLAM System through the Combination of Points and Line SegmentsMay 26 2017Apr 09 2018Traditional approaches to stereo visual SLAM rely on point features to estimate the camera trajectory and build a map of the environment. In low-textured environments, though, it is often difficult to find a sufficient number of reliable point features ... More
Training a Convolutional Neural Network for Appearance-Invariant Place RecognitionMay 27 2015Place recognition is one of the most challenging problems in computer vision, and has become a key part in mobile robotics and autonomous driving applications for performing loop closure in visual SLAM systems. Moreover, the difficulty of recognizing ... More
Intense structures of different momentum fluxes in turbulent channelsJun 22 2018The effect of different definitions of the momentum flux on the properties of the coherent structures of the logarithmic region of wall-bounded turbulence is investigated by comparing the structures of intense tangential Reynolds stress with those of ... More
Three cubes in arithmetic progression over quadratic fieldsSep 01 2009We study the problem of the existence of arithmetic progressions of three cubes over quadratic number fields Q(sqrt(D)), where D is a squarefree integer. For this purpose, we give a characterization in terms of Q(sqrt(D))-rational points on the elliptic ... More
Modular Curves Of Genus 2May 28 2001We prove that there is only a finite number of genus 2 curves C defined over Q such that there exists a nonconstant morphism pi:X_1(N) --->C defined over Q and the jacobian of C, J(C), is a Q-factor of the new part of the jacobian of X_1(N), J_1(N)^{new}. ... More
On arithmetic progressions on Edwards curvesApr 16 2013Apr 07 2015Let m be a positive integer and a,q two rational numbers. Denote by AP_m(a,q) the set of rational numbers d such that a,a+q,...,a+(m-1)q form an arithmetic progression in the Edwards curve E_d:x^2+y^2=1+d x^2 y^2. We study the set AP_m(a,q) and we parametrize ... More
Covering techniques and rational points on some genus 5 curvesNov 22 2013Apr 07 2015We describe a method that allows, under some hypotheses, to compute all the rational points of some genus 5 curves defined over a number field. This method is used to solve some arithmetic problems that remained open.
A Detection of Sgr A* in the far infraredJun 19 2018We report the first detection of the Galactic Centre massive black hole, Sgr~A*, in the far infrared. Our measurements were obtained with PACS on board the \emph{Herschel} satellite at $100~\mathrm{\mu m}$ and $160~\mathrm{\mu m}$. While the warm dust ... More
Meson-exchange currents and quasielastic predictions for charged-current neutrino-12C scattering in the superscaling approachDec 04 2014Apr 14 2015We evaluate and discuss the impact of meson-exchange currents (MECs) on charged-current quasielastic neutrino cross sections. We consider the nuclear transverse response arising from two-particle two-hole states excited by the action of electromagnetic, ... More
Testing nuclear models via neutrino scatteringNov 21 2014Recent progresses on the relativistic modeling of neutrino-nucleus reactions are presented and the results are compared with high precision experimental data in a wide energy range.
The structure behind the Galactic bar traced by red clump stars in the VVV surveySep 11 2018Red clump stars are commonly used to map the reddening and morphology of the inner regions of the Milky Way. We use the new photometric catalogues of the VISTA Variables in the V\'ia L\'actea survey to achieve twice the spatial resolution of previous ... More
Room-temperature ferromagnetism in the mixtures of the TiO2 and Co3O4 powdersMar 30 2009We report here the observation of ferromagnetism (FM) at 300 K in mixtures of TiO2 and Co3O4 powders despite the antiferromagnetic and diamagnetic character of both oxides respectively. The ferromagnetic behavior is found in the early stages of reaction ... More
Privacy Preserving Distance Computation using Somewhat-trusted Third PartiesSep 16 2016Sep 23 2016A critically important component of most signal processing procedures is that of computing the distance between signals. In multi-party processing applications where these signals belong to different parties, this introduces privacy challenges. The signals ... More
Sub-arcsecond radio continuum mapping in and around the spiral galaxy NGC3351 using MERLINApr 26 2010We report sub-arcsecond scale radio continuum observations of a field of 35 by 22 arcmin centred in NGC3351 obtained with the Multi-Element Radio Linked Interferometer Network (MERLIN). We found 23 radio sources in this field, 6 of which are projected ... More
Constraints on Jupiters from observations of Galactic Bulge microlensing events during 2000Jul 03 2002We present observations of 8 Galactic Bulge microlensing events taken with the 1.0m JKT on La Palma during 2000 June and July. The JKT observing schedule was optimized using a prioritizing algorithm to automatically update the target list. For most of ... More
Representation stability for the cohomology of the moduli space M_g^nJun 06 2011Oct 11 2011Let M_g^n be the moduli space of Riemann surfaces of genus g with n labeled marked points. We prove that, for g \geq 2, the cohomology groups {H^i(M_g^n;Q)}_{n=1}^{\infty} form a sequence of Sn representations which is representation stable in the sense ... 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
Hydrodynamics from the Dp-braneMar 09 2007We complete the computation of viscous transport coefficients in the near horizon geometries that arise from a stack of black Dp-branes for p=2,...,6 in the decoupling limit. The main new result is the obtention of the bulk viscosity which, for all p, ... More
Galaxy Evolution, Deep Galaxy Counts and the Near-IR Cosmic Infrared BackgroundFeb 26 1998Sep 15 1998Accurate synthetic models of stellar populations are constructed and used in evolutionary models of stellar populations in forming galaxies. Following their formation, the late type galaxies are assumed to follow the Schmidt law for star formation, while ... More
Approximate linear minimum variance filters for continuous-discrete state space models: convergence and practical algorithmsJul 25 2012Dec 17 2013In this paper, approximate Linear Minimum Variance (LMV) filters for continuous-discrete state space models are introduced. The filters are obtained by means of a recursive approximation to the predictions for the first two moments of the state equation. ... More
Modified Cold-Dark-Matter models in light of 53W091 an old galaxy at high zOct 22 1996The epoch of galaxy formation provides an important additional test of cosmological theories. Cold-dark-matter (CDM) models with cosmological constant ($\Lambda$) are designed to account for the observed excess power in galaxy distribution, but at the ... More
Progress in the dynamical parton distributionsJun 18 2012Jun 20 2012The present status of the (JR) dynamical parton distribution functions is reported. Different theoretical improvements, including the determination of the strange sea input distribution, the treatment of correlated errors and the inclusion of alternative ... More
Approximate continuous-discrete filters for the estimation of diffusion processes from partial and noisy observationsDec 15 2012Dec 18 2013In this paper, an alternative approximation to the innovation method is introduced for the parameter estimation of diffusion processes from partial and noisy observations. This is based on a convergent approximation to the first two conditional moments ... More
Approximate discrete-time schemes for the estimation of diffusion processes from complete observationsDec 08 2012Dec 18 2013In this paper, a modification of the conventional approximations to the quasi-maximum likelihood method is introduced for the parameter estimation of diffusion processes from discrete observations. This is based on a convergent approximation to the first ... More
On the discretization of nonholonomic dynamics in $\mathbb{R}^n$Jul 08 2014In this paper we explore the nonholonomic Lagrangian setting of mechanical systems in local coordinates on finite-dimensional configuration manifolds. We prove existence and uniqueness of solutions by reducing the basic equations of motion to a set of ... More
On symmetric square values of quadratic polynomialsJan 26 2010We prove that there does not exist a non-square quadratic polynomial with integer coefficients and an axis of symmetry which takes square values for N consecutive integers for N=7 or N >= 9. At the opposite, if N <= 6 or N=8 there are infinitely many. ... More
Arithmetic progressions of four squares over quadratic fieldsMar 23 2009Let d be a squarefree integer. Does there exist four squares in arithmetic progression over Q(sqrt{d})? We shall give a partial answer to this question, depending on the value of d. In the affirmative case, we construct explicit arithmetic progressions ... More
On the modularity level of modular abelian varieties over number fieldsFeb 02 2010Let f be a weight two newform for Gamma_1(N) without complex multiplication. In this article we study the conductor of the absolutely simple factors B of the variety A_f over certain number fields L. The strategy we follow is to compute the restriction ... More
$Ξ^{-}$ and $\barΞ^{+}$ baryon production in Au+Au collisions at $\sqrt{s_{NN}}=130$ GeVOct 25 2002We report preliminary results on the centrality dependence of the $\Xi^{-}$ and $\bar{\Xi}^{+}$ production at mid-rapidity in $\sqrt{s_{NN}}=130$ GeV Au+Au collisions from the STAR experiment. For the most central data the obtained yields suggest a saturation ... More
Brief history of the Lehmann Symposia: Origins, goals and motivationNov 07 2006The idea of the Lehmann Symposia as platforms to encourage a revival of interest in fundamental questions in theoretical statistics, while keeping in focus issues that arise in contemporary interdisciplinary cutting-edge scientific problems, developed ... More
Is the beta phase maximal ?Apr 20 2005Jun 06 2005The current experimental determination of the absolute values of the CKM elements indicates that 2|Vub / Vcb/ Vus| = (1-z) with z given by z = 0.19 +(-) 0.14. This fact implies that irrespective of the form of the quark Yukawa matrices, the measured value ... More
Fixed points of nilpotent actions on ${\mathbb S}^{2}$Aug 22 2012May 06 2014We prove that a nilpotent subgroup of orientation preserving $C^{1}$ diffeomorphisms of ${\mathbb S}^{2}$ has a finite orbit of cardinality at most two. We also prove that a finitely generated nilpotent subgroup of orientation preserving $C^{1}$ diffeomorphisms ... More