Results for "Javier Gonzalez-Jimenez"

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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
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
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
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
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
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
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.
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
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
On fields of definition of torsion points of elliptic curves with complex multiplicationSep 09 2009Jun 04 2010For any elliptic curve E defined over the rationals with complex multiplication and for every prime p, we describe the image of the mod p Galois representation attached to E. We deduce information about the field of definition of torsion points of these ... 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 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
Elliptic Curves with abelian division fieldsNov 27 2015Let E be an elliptic curve over Q, and let n=>1. The central object of study of this article is the division field Q(E[n]) that results by adjoining to Q the coordinates of all n-torsion points on E(Q). In particular, we classify all curves E/Q such that ... More
On the minimal degree of definition of p-primary torsion subgroups of elliptic curvesNov 25 2015In this article, we study the minimal degree [K(T):K] of a p-subgroup T <= E(\overline{K})_tors for an elliptic curve E/K defined over a number field K. Our results depend on the shape of the image of the p-adic Galois representation \rho_{E,p^infty}:Gal_K-->GL(2,Z_p). ... More
Torsion of rational elliptic curves over quadratic fields IINov 13 2014Apr 07 2015Let E be an elliptic curve defined over Q and let G=E(Q)_tors be the associated torsion group. In a previous paper, the authors studied, for a given G, which possible groups G\leq H could appear such that H=E(K)_tors, for [K:Q]=2. In the present paper, ... More
On the torsion of rational elliptic curves over quartic fieldsJun 02 2016Mar 18 2019Let 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 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.
Constraints on cosmic opacity and beyond the standard model physics from cosmological distance measurementsApr 12 2010We update constraints on cosmic opacity by combining recent SN Type Ia data compilation with the latest measurements of the Hubble expansion at redshifts between 0 and 2. The new constraint on the parameter $\epsilon$ parametrising deviations from the ... More
Quantum Information Metric and Berry Curvature from a Lagrangian ApproachJan 31 2017Feb 03 2017We take as a starting point an expression for the quantum geometric tensor recently derived in the context of the gauge/gravity duality. We proceed to generalize this formalism in such way it is possible to compute the geometrical phases of quantum systems. ... 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
Mass Composition Sensitivity of an Array of Water Cherenkov and Scintillation DetectorsSep 08 2011We consider a hybrid array composed of scintillation and water Cherenkov detectors designed to measure the cosmic ray primary mass composition at energies of about 1 EeV. We have developed a simulation and reconstruction chain to study the theoretical ... 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
Relation between halo spin and cosmic web filaments at z=3Jun 14 2016Nov 04 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
Galois Theory, discriminants and torsion subgroups of elliptic curvesNov 10 2008Jun 30 2009We find a tight relationship between the torsion subgroup and the image of the mod 2 Galois representation associated to an elliptic curve defined over the rationals. This is shown using some characterizations for the squareness of the discriminant of ... 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 Simple Power Analysis Attack on the Twofish Key ScheduleNov 22 2016This paper introduces an SPA power attack on the 8-bit implementation of the Twofish block cipher. The attack is able to unequivocally recover the secret key even under substantial amounts of error. An initial algorithm is described using exhaustive search ... 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
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
Electrostatic analogy of the Jackiw-Rebbi zero energy stateDec 04 2017We present an analogy between the one dimensional Poisson equation in inhomogeneous media and the Dirac equation in one space dimension with a Lorentz scalar potential for zero energy. We illustrate how the zero energy state in the Jackiw-Rebbi model ... 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
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
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
On the Equivalence between Interference and Eavesdropping in Wireless CommunicationsJul 31 2014Feb 25 2015We show that the problem of analyzing the outage probability in cellular systems affected by co-channel interference and background noise is mathematically equivalent to the problem of analyzing the wireless information-theoretic security in terms of ... 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
Prospects for indirect MeV Dark Matter detection with Gamma Rays in light of Cosmic Microwave Background ConstraintsMay 02 2017Aug 22 2017The self-annihilation of dark matter particles with mass in the MeV range can produce gamma rays via prompt or secondary radiation. The annihilation rate for such light dark matter particles is however tightly constrained by cosmic microwave background ... More
Topological signature for periodic motion recognitionApr 11 2019In this paper, we present an algorithm that computes the topological signature for a given periodic motion sequence. Such signature consists of a vector obtained by persistent homology which captures the topological and geometric changes of the object ... 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
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
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
Updating seismic hazard at ParkfieldOct 30 2004Nov 16 2005The occurrence of the September 28, 2004 Mw=6.0 mainshock at Parkfield, California, has significantly increased the mean and aperiodicity of the series of time intervals between mainshocks in this segment of the San Andreas fault. We use five different ... 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
Use of neural networks for the identification of new z>=3.6 QSOs from FIRST-SDSS DR5Sep 03 2008We aim to obtain a complete sample of redshift > 3.6 radio QSOs from FIRST sources having star-like counterparts in the SDSS DR5 photometric survey (r<=20.2). We found that simple supervised neural networks, trained on sources with SDSS spectra, and using ... 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
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
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
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
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
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
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
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
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
Functional Requirements-Based Automated Testing for AvionicsJul 05 2017We propose and demonstrate a method for the reduction of testing effort in safety-critical software development using DO-178 guidance. We achieve this through the application of Bounded Model Checking (BMC) to formal low-level requirements, in order to ... More
Hamilton-Dirac systems for charged particles in gauge fieldsOct 13 2014Apr 07 2015In this work, we use the Sternberg phase space (which may be considered as the classical phase space of particles in gauge fields) in order to explore the dynamics of such particles in the context of Hamilton-Dirac systems and their associated Hamilton-Pontryagin ... 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
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
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
Velocity Dispersions and Stellar Populations of the Most Compact and Massive Early-Type Galaxies at Redshift ~1Jul 22 2011We present Gran-Telescopio-Canarias/OSIRIS optical spectra of 4 of the most compact and massive early-type galaxies in the Groth Strip Survey at redshift z~1, with effective radii Reff=0.5-2.4 kpc and photometric stellar masses Mstar=1.2-4x10^11 Msun. ... 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
Extinction ratios in the inner Galaxy as revealed by the VVV surveyOct 13 2017Interstellar extinction towards the Galactic Center is large and significantly differential. Its reddening and dimming effects in red clump stars in the Galactic Bulge can be exploited to better constrain the extinction law towards the innermost Galaxy. ... 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.
Virtual-organism toy-model as a tool to develop bioinformatics approaches of Systems Biology for medical-target discoveryJan 11 2013Systems Biology has emerged in the last years as a new holistic approach based on the global understanding of cells instead of only being focused on their individual parts (genes or proteins), to better understand the complexity of human cells. Since ... More
A new near-IR window of low extinction in the Galactic planeApr 20 2018The windows of low extinction in the Milky Way (MW) plane are rare but important because they enable us to place structural constraints on the opposite side of the Galaxy, which has hitherto been done rarely. We use the near-infrared (near-IR) images ... More
Measurements of minimum entropy at K-shell photoelectric effect provides the radius and shape of the protonJan 04 2017Jan 12 2017Constructive resonances with minimum entropy are derived from measurements of photoelectric effect cross sections at atomic K-shell thresholds. A resonance region with optimal constructive interference is given by a principal wave length {\lambda} of ... More
Alignment of Silicon tracking systems R&D on Semitransparent Microstrip SensorsJan 09 2009We summarize the R&D activities on a novel semitransparent microstrip sensor to be used on laser-based alignment systems for silicon trackers. The new sensor is used both for particle tracking and laser detection. The aim of this research line is to increase ... 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
Infinitesimal bendings of complete Euclidean hypersurfacesJun 29 2017A local description of the non-flat infinitesimally bendable Euclidean hypersurfaces was recently given by Dajczer and Vlachos \cite{DaVl}. From their classification, it follows that there is an abundance of infinitesimally bendable hypersurfaces that ... 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
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
Keep an Eye on Venezuelan Elections! (Vigilad las elecciones venezolanas)Sep 17 2012Sep 21 2012Starting with the 2004 recall referendum, an important opposition sector to President Chavez has questioned the integrity of the Venezuelan electoral system, and casts doubt on the legitimacy and impartiality of the upcoming 2012 presidential elections ... More
Calculation of the determinant in the Wheeler-De Witt equationFeb 19 2013The Riemann-zeta function regularization procedure has been studied intensively as a good method in the computation of the determinant for pseudo-diferential operator. In this paper we propose a different approach for the computation of the determinant ... More
HE-LHC: requirements from beam vacuumAug 08 2011First thoughts on the design of the beam vacuum system for the High Energy LHC (HE-LHC) are given with a particular focus on the impact of the synchrotron radiation. In the HE-LHC, the vacuum dynamic effects induced by the circulating beams are expected ... More
Explicit drain-current model of graphene field-effect transistors targeting analog and radio-frequency applicationsMar 08 2011Jun 24 2011We present a compact physics-based model of the current-voltage characteristics of graphene field-effect transistors, of especial interest for analog and radio-frequency applications where bandgap engineering of graphene could be not needed. The physical ... 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
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
On sets defining few ordinary solidsAug 20 2018Let $\mathcal{S}$ be a set of $n$ points in real four-dimensional space, no four coplanar and spanning the whole space. We prove that if the number of solids incident with exactly four points of $\mathcal{S}$ is less than $Kn^3$ for some $K=o(n^{\frac{1}{7}})$ ... More
On the cohomology of pure mapping class groups as FI-modulesJul 30 2012Sep 30 2013In this paper we apply the theory of finitely generated FI-modules developed by Church, Ellenberg and Farb to certain sequences of rational cohomology groups. Our main examples are the cohomology of the moduli space of n-pointed curves, the cohomology ... 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
Weak type estimates associated to Burkholder's martingale inequalityAug 24 2005Aug 26 2005Given a probability space $(\Omega, \mathsf{A}, \mu)$, let $\mathsf{A}_1, \mathsf{A}_2, ...$ be a filtration of $\sigma$-subalgebras of $\mathsf{A}$ and let $\mathsf{E}_1, \mathsf{E}_2, ...$ denote the corresponding family of conditional expectations. ... More
The Sun in Hidden PhotonsFeb 22 2012We present some aspects and first results of the emission of sub-eV mass hidden photons from the Sun. The contribution from a resonant region below the photosphere can be quite significant, raising previous estimates. This is relevant for the Telescope ... More
A Hidden Microwave Background? -- signatures of photon-WISP oscillations in the CMBFeb 02 2010The existence and cosmological signatures of a relic background of very weakly interacting sub-eV particles (WISPs), produced by photon-WISP oscillations is reviewed.
Simplicial embeddings between pants graphsJan 13 2009We prove that, except in some low-complexity cases, every locally injective simplicial map between pants graphs is induced by a $\pi_1$-injective embedding between the corresponding surfaces.
The Weil-Petersson geometry of the five-times punctured sphereJan 31 2005Apr 12 2005We give a new proof that the completion of the Weil-Petersson metric on Teichm\"uller space is Gromov-hyperbolic if the surface is a five-times punctured sphere or a twice-punctured torus. Our methods make use of the synthetic geometry of the Weil-Petersson ... More
Beyond Special and General Relativity. Neutrinos and CosmologyFeb 04 2010The widely accepted description of the present cosmic acceleration and the neutrino oscillations in terms of a cosmological constant and neutrino masses, respectively, seems conceptually not very satisfactory. From a phenomenological perspective, the ... More
Free group algebras in division rings with valuation IJun 27 2018Let $R$ be an algebra over a commutative ring $k$. Suppose that $R$ is endowed with a descending filtration indexed on an ordered group $(G,<)$ such that the restriction to $k$ is positive. We show that the existence of free algebras on a certain set ... More
Boundness of intersection numbers for actions by two-dimensional biholomorphismsJun 12 2018Apr 08 2019We say that a group $G$ of local (maybe formal) biholomorphisms satisfies the uniform intersection property if the intersection multiplicity $(\phi (V), W)$ takes only finitely many values as a function of $G$ for any choice of analytic sets $V$ and $W$. ... More
The generalized quantum isotonic oscillatorMay 07 2010Recently, it has been proved that a nonlinear quantum oscillator, generalization of the isotonic one, is exactly solvable for certain values of its parameters. Here we show that the Schroedinger equation for such an oscillator can be transformed into ... More
Results from MAGIC's first observation cycle on galactic sourcesSep 06 2006During its Cycle I, the MAGIC telescope targeted about 250 hours several galactic sources sought to be, or detected previously by other experiments in the same energy domain, gamma-ray emitters. This paper reviews some results of such MAGIC observations ... More
Combinatorial problems in finite fields and Sidon setsMar 18 2010Feb 18 2011We use Sidon sets to present an elementary method to study some combinatorial problems in finite fields, such as sum product estimates, solubility of some equations and distribution of sequences in small intervals. We obtain classic and more recent results ... More
Communication Using Eigenvalues of Higher Multiplicity of the Nonlinear Fourier TransformFeb 21 2018Oct 15 2018A generalized Nonlinear Fourier Transform (GNFT), which includes eigenvalues of higher multiplicity, is considered for information transmission over fiber optic channels. Numerical algorithms are developed to compute the direct and inverse GNFTs. For ... More
Extension of formal conjugations between diffeomorphismsApr 20 2011We study the formal conjugacy properties of germs of complex analytic diffeomorphisms defined in the neighborhood of the origin of ${\mathbb C}^{n}$. More precisely, we are interested on the nature of formal conjugations along the fixed points set. We ... More
Embedding smooth and formal diffeomorphisms through the Jordan-Chevalley decompositionJul 19 2011In [Xiang Zhang, The embedding flows of $C^{\infty}$ hyperbolic diffeomorphisms, J. Differential Equations 250 (2011), no. 5, 2283-2298] Zhang proved that any local smooth hyperbolic diffeomorphism whose eigenvalues are weakly nonresonant is embedded ... More