Results for "Hildebrando M. Rodrigues"

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Stability problems in non autonomous linear differential equations in infinite dimensionsJun 11 2019One goal of this paper is to study robustness of stability of nonautonomous linear ordinary differential equations under integrally small perturbations in an infinite dimensional Banach space. Some applications are obtained to the case of rapid oscillatory ... More
An example on Lyapunov stability and linearizationFeb 06 2019The purpose of this paper is to present an example of a C1 (in the Fr\'echet sense) discrete dynamical system in a infinite-dimensional separable Hilbert space for which the origin is an exponentially asymptotically stable fixed point, but such that its ... More
Combining the regularization strategy and the SQP to solve MPCC - a MATLAB implementationOct 20 2015Mathematical Program with Complementarity Constraints (MPCC) plays a very important role in many fields such as engineering design, economic equilibrium, multilevel game, and mathematical programming theory itself. In theory its constraints fail to satisfy ... More
The fractional volatility model: No-arbitrage, leverage and completenessMay 13 2012Based on a criterion of mathematical simplicity and consistency with empirical market data, a stochastic volatility model has been obtained with the volatility process driven by fractional noise. Depending on whether the stochasticity generators of log-price ... More
Enhancement of the electromechanical response in ferroelectric ceramics by designNov 12 2010It is demonstrated based on continuum mechanics modeling and simulation that it is possible to obtain polycrystalline ceramic ferroelectric materials which beggars single crystals in electromechanical properties. The local inhomogeneities at the ferroelectric ... More
The spread of a financial virus through Europe and beyondJan 22 2019We analyse the importance of international relations between countries on the financial stability. The contagion effect in the network is tested by implementing an epidemiological model, comprising a number of European countries and using bilateral data ... More
Scalar and higher even spin glueball masses from an anomalous modified holographic modelNov 29 2016Jun 12 2018In this work, within an anomalous modified holographic softwall model, we calculate analytically the masses of the scalar glueball with its radial excitations and higher even glueball spin states, with $P=C=+1$, from a single mass equation. Using this ... More
Lorentz-violating contributions of the Carroll-Field-Jackiw model to the CMB anisotropyOct 01 2008Dec 11 2008We study the finite temperature properties of the Maxwell-Carroll-Field-Jackiw (MCFJ) electrodynamics for a purely spacelike background. Starting from the associated finite temperature partition function, a modified black body spectral distribution is ... More
Parametric identification of the dynamics of inter-sectoral balance: modelling and forecastingMar 29 2019This work is devoted to modelling and identification of the dynamics of the inter-sectoral balance of a macroeconomic system. An approach to the problem of specification and identification of a weakly formalized dynamical system is developed. A matching ... More
Intermittency and Nonextensivity in Turbulence and Financial MarketsJul 22 1999Jul 23 1999We present a new framework for modeling the statistical behavior of both fully developed turbulence and short-term dynamics of financial markets based on the nonextensive thermostatistics proposed by Tsallis. We also show that intermittency -- strong ... More
Stability of periodic waves in Hamiltonian PDEs of either long wavelength or small amplitudeOct 11 2017Stability criteria have been derived and investigated in the last decades for many kinds of periodic traveling wave solutions to Hamiltonian PDEs. They turned out to depend in a crucial way on the negative signature of the Hessian matrix of action integrals ... More
Twist Two Operator Approach for Even Spin Glueball Masses and Pomeron Regge Trajectory from the Hardwall ModelNov 11 2016Apr 18 2017We compute the masses of even spin glueball states $ J^{PC} $, with $ P=C=+1 $, using a twist two operator from an AdS/QCD model known as the hardwall model, using Dirichlet and Neumann boundary conditions. Within this approach, we found that the glueball ... More
The risk of contagion spreading and its optimal control in the economyDec 17 2018The global crisis of 2008 provoked a heightened interest among scientists to study the phenomenon, its propagation and negative consequences. The process of modelling the spread of a virus is commonly used in epidemiology. Conceptually, the spread of ... More
Generalized Thermostatistical Description of Intermittency and Non-extensivity in Turbulence and Financial MarketsOct 26 2000We describe a simple and accurate framework for modeling the statistical behavior of both fully developed turbulence and short-term dynamics of financial markets based on the formalism of Tsallis' generalized non-extensive thermostatistics. Within this ... More
Deconfinement phase transition in a magnetic field in 2+1 dimensions from holographic modelsSep 26 2017Mar 12 2018Using two different models from holographic quantum chromodynamics (QCD) we study the deconfinement phase transition in $2+1$ dimensions in the presence of a magnetic field. Working in 2+1 dimensions lead us to {\sl exact} solutions on the magnetic field, ... More
Weighted Alexandrov-Fenchel inequalities in hyperbolic space and a conjecture of Ge, Wang and WuFeb 19 2019Apr 25 2019We consider a conjecture made by Ge, Wang and Wu regarding weighted Alexandrov-Fenchel inequalities for horospherically convex hypersurfaces in hyperbolic space (a bound, for some physically motivated weight function, of the weighted integral of the $k^{\mathrm{th}}$ ... More
A Distributed Auctioneer for Resource Allocation in Decentralized SystemsApr 25 2016In decentralized systems, nodes often need to coordinate to access shared resources in a fair manner. One approach to perform such arbitration is to rely on auction mechanisms. Although there is an extensive literature that studies auctions, most of these ... More
Local Conjugacy of Irreducible Hyperbolic Toral AutomorphismsNov 17 2016This paper is dedicated to the conjugacy problem in $GL(n,\Z)$ and its connection with algebraic number theory. This connection may be summed up in the Latimer-MacDuffee-Taussky Theorem, which, in a very broad sense, identifies the conjugacy relation ... More
Fractional derivatives in Dengue epidemicsAug 08 2011We introduce the use of fractional calculus, i.e., the use of integrals and derivatives of non-integer (arbitrary) order, in epidemiology. The proposed approach is illustrated with an outbreak of dengue disease, which is motivated by the first dengue ... More
Magnetic catalysis and inverse magnetic catalysis in (2+1)-dimensional gauge theories from holographic modelsOct 19 2017Jun 06 2018We study the deconfinement phase transition in $ (2+1) $-dimensional holographic $ SU(N) $ gauge theories in the presence of an external magnetic field from the holographic hard and soft wall models. We obtain exact solutions for the critical temperature ... More
Second Order Swarm IntelligenceJun 13 2013An artificial Ant Colony System (ACS) algorithm to solve general-purpose combinatorial Optimization Problems (COP) that extends previous AC models [21] by the inclusion of a negative pheromone, is here described. Several Travelling Salesman Problem (TSP) ... More
Influence of Thickness and Contact Area on the Performance of PDMS-Based Triboelectric NanogeneratorsMar 27 2018Triboelectric nanogenerators (TENGs) are an emerging mechanical energy harvesting technology that was recently demonstrated. Due to their flexibility, they can be fabricated in various configurations and consequently have a large number of applications. ... More
Quantizations from (P)OVM'sOct 11 2013We explain the powerful role that operator-valued measures can play in quantizing any set equipped with a measure, for instance a group (resp. group coset) with its invariant (resp. quasi-invariant) measure. Coherent state quantization is a particular ... More
Weyl-Heisenberg integral quantization(s): a compendiumMar 24 2017We present a list of formulae useful for Weyl-Heisenberg integral quantizations, with arbitrary weight, of functions or distributions on the plane. Most of these formulae are known, others are original. The list encompasses particular cases like Weyl-Wigner ... More
Scattering by linear defects in graphene: a tight-binding approachOct 31 2012Jul 16 2013We develop an analytical scattering formalism for computing the transmittance through periodic defect lines within the tight-binding model of graphene. We first illustrate the method with a relatively simple case, the pentagon-only defect line. Afterwards, ... More
ANSIG - An Analytic Signature for Arbitrary 2D Shapes (or Bags of Unlabeled Points)Oct 19 2010In image analysis, many tasks require representing two-dimensional (2D) shape, often specified by a set of 2D points, for comparison purposes. The challenge of the representation is that it must not only capture the characteristics of the shape but also ... More
Optimal control of a dengue epidemic model with vaccinationAug 15 2011We present a SIR+ASI epidemic model to describe the interaction between human and dengue fever mosquito populations. A control strategy in the form of vaccination, to decrease the number of infected individuals, is used. An optimal control approach is ... More
Optimization of Dengue Epidemics: a test case with different discretization schemesJan 19 2010The incidence of Dengue epidemiologic disease has grown in recent decades. In this paper an application of optimal control in Dengue epidemics is presented. The mathematical model includes the dynamic of Dengue mosquito, the affected persons, the people's ... More
Towards a core genome: pairwise similarity searches on interspecific genomic dataJul 21 2008The phenomenon of gene conservation is an interesting evolutionary problem related to speciation and adaptation. Conserved genes are acted upon in evolution in a way that preserves their function despite other structural and functional changes going on ... More
Chiral Symmetry Breaking and Restoration in (2+1) Dimensions from Holography: Magnetic and Inverse Magnetic CatalysisJul 31 2018Nov 10 2018We study the chiral symmetry breaking and restoration in $ (2+1) $-dimensional gauge theories from the holographic hard and softwall models. We describe the behavior of the chiral condensate in the presence of an external magnetic field for both models ... More
Zigzag graphene nanoribbon edge reconstruction with Stone-Wales defectsJul 24 2011In this article, we study zigzag graphene nanoribbons with edges reconstructed with Stone-Wales defects, by means of an empirical (first-neighbor) tight-binding method, with parameters determined by ab-initio calculations of very narrow ribbons. We explore ... More
Bioeconomic Perspectives to an Optimal Control Dengue ModelMar 27 2013A model with six mutually-exclusive compartments related to dengue is studied. Three vector control tools are considered: insecticides (larvicide and adulticide) and mechanical control. The basic reproduction number associated to the model is presented. ... More
Dengue in Cape Verde: vector control and vaccinationApr 02 2012In 2009, for the first time in Cape Verde, an outbreak of dengue was reported and over twenty thousand people were infected. Only a few prophylactic measures were taken. The effects of vector control on disease spreading, such as insecticide (larvicide ... More
Scattering by linear defects in graphene: a continuum approachAug 03 2012Oct 09 2012We study the low-energy electronic transport across periodic extended defects in graphene. In the continuum low-energy limit, such defects act as infinitesimally thin stripes separating two regions where Dirac Hamiltonian governs the low-energy phenomena. ... More
A note about combinatorial sequences and Incomplete Gamma functionSep 10 2013In this short note we present a set of interesting and useful properties of a one-parameter family of sequences including factorial and subfactorial, and their relations to the Gamma function and the incomplete Gamma function.
Holographic Description of Chiral Symmetry Breaking in a Magnetic Field in 2+1 Dimensions with an Improved DilatonNov 09 2018We consider a holographic description of the chiral symmetry breaking in an external magnetic field in $ (2+1) $-dimensional gauge theories from the softwall model using an improved dilaton field profile given by $\Phi(z) = - kz^2 + (k+k_1)z^2\tanh (k_{2}z^2)$. ... More
Electronic transport across linear defects in grapheneApr 03 2015We investigate the low-energy electronic transport across grain boundaries in graphene ribbons and infinite flakes. Using the recursive Green's function method, we calculate the electronic transmission across different types of grain boundaries in graphene ... More
Engineering phonon-photon interactions with a driven trapped ion in a cavitySep 26 2006We show how to generate quadratic and bi-quadratic phonon-photon interactions through a driven three-level ion inside a cavity. With such a system it is possible to squeeze the cavity-field state, the ion motional state or even the entangled phonon-photon ... More
Photometry and dynamics of the minor mergers AM\,1228-260 and AM\,2058-381Jun 20 2015Jun 23 2015We investigate interaction effects on the dynamics and morphology of the galaxy pairs AM\,2058-381 and AM\,1228-260. This work is based on $r'$ images and long-slit spectra obtained with the Gemini Multi-Object Spectrograph at the Gemini South Telescope. ... More
A distance-based tool-set to track inconsistent urban structures through complex-networksMar 24 2018Complex networks can be used for modeling street meshes and urban agglomerates. With such a model, many aspects of a city can be investigated to promote a better quality of life to its citizens. Along these lines, this paper proposes a set of distance-based ... More
Reviewing Data Visualization: an Analytical Taxonomical StudyJun 09 2015This paper presents an analytical taxonomy that can suitably describe, rather than simply classify, techniques for data presentation. Unlike previous works, we do not consider particular aspects of visualization techniques, but their mechanisms and foundational ... More
Complex Entropic Forms for Gradient Pattern Analysis of Spatio-temporal DynamicsMar 25 2000In this paper we describe two new computational operators, called complex entropic form (CEF) and generalized complex entropic form (GEF), for pattern characterization of spatially extended systems. Besides of being a measure of regularity, both operators ... More
An Electromagnet-Based Magnetically-Activated Thermal Switch Without Moving PartsMar 28 2018With the ever increasing power dissipation in electrical devices, new thermal management solutions are in high demand to maintain an optimal operating temperature and efficient performance. In particular, recently developed magnetically-activated thermal ... More
The trace formulas yield the inverse metric formulaMay 06 1998May 03 2000It is a well-known fact that the first and last non-trivial coefficients of the characteristic polynomial of a linear operator are respectively its trace and its determinant. This work shows how to compute recursively all the coefficients as polynomial ... More
Heisenberg Spins on a Circular Conical SurfaceJan 29 2004We investigate classical Heisenberg spins on a conical surface. The energy and configuration of non-trivial spin distributions are obtained using a non-conventional method based on Einstein theory of gravity in lower dimensions.
Multiobjective approach to optimal control for a dengue transmission modelJun 26 2015During the last decades, the global prevalence of dengue progressed dramatically. It is a disease which is now endemic in more than one hundred countries of Africa, America, Asia and the Western Pacific. This study addresses a mathematical model for the ... More
Dengue disease: a multiobjective viewpointDec 03 2015During the last decades, the global prevalence of dengue progressed dramatically. It is a disease that is now endemic in more than one hundred countries of Africa, America, Asia, and the Western Pacific. In this paper, we present a mathematical model ... More
Linear Asymptotic Stability and Modulation Behavior near Periodic Waves of the Korteweg-de Vries EquationJun 19 2017We provide a detailed study of the dynamics obtained by linearizing the Korteweg-de Vries equation about one of its periodic traveling waves, a cnoidal wave. In a suitable sense, linearly analogous to space-modulated stability, we prove global-in-time ... More
Attractors in complex networksSep 10 2017In the framework of the generalized Lotka Volterra model, solutions representing multispecies sequencial competition can be predictable with high probability. In this paper, we show that it occurs because the corresponding "heteroclinic channel" forms ... More
Comparing six evolutionary population synthesis models through spectral synthesis on galaxiesFeb 10 2010We compare six popularly used evolutionary population synthesis (EPS) models (BC03, CB07, Ma05, GALEV, GRASIL, Vazdekis/Miles) through fitting the full optical spectra of six representative types of galaxies (star-forming and composite galaxies, Seyfert ... More
Can noncommutativity affect the whole history of the Universe?Sep 16 2011Feb 11 2016We study a classical, noncommutative (NC), Friedmann-Robertson-Walker cosmological model. The spatial sections may have positive, negative or zero constant curvatures. The matter content is a generic perfect fluid. The initial noncommutativity between ... More
Measurement of the absolute reflectance of polytetrafluoroethylene (PTFE) immersed in liquid xenonDec 23 2016The performance of a detector using liquid xenon (LXe) as a scintillator is strongly dependent on the collection efficiency for xenon scintillation light, which in turn is critically dependent on the reflectance of the surfaces that surround the active ... More
Sheaves as modulesNov 28 2007Jan 28 2008We revisit sheaves on locales by placing them in the context of the theory of quantale modules. The local homeomorphisms $p:X\to B$ are identified with the Hilbert $B$-modules that are equipped with a natural notion of basis. The homomorphisms of these ... More
Large N Spectrum of two Matrices in a Harmonic Potential and BMN energiesOct 28 2005The large N spectrum of the quantum mechanical hamiltonian of two hermitean matrices in a harmonic potential is studied in a framework where one of the matrices is treated exactly and the other is treated as a creation operator impurity in the background ... More
Global stability in some one-dimensional non-autonomous discrete periodic population modelsMar 08 2016For some one-dimensional discrete-time autonomous population models, local stability implies global stability of the positive equilibrismo point. One of the known techniques is the enveloping method. In this paper we extend the enveloping method to one ... More
Boundary crisis for degenerate singular cyclesSep 13 2016Mar 22 2017The term boundary crisis refers to the destruction or creation of a chaotic attractor when parameters vary. The locus of a boundary crisis may contain regions of positive Lebesgue measure marking the transition from regular dynamics to the chaotic regime. ... More
Application of SIR epidemiological model: new trendsNov 08 2016The simplest epidemiologic model composed by mutually exclusive compartments SIR (susceptible-infected-susceptible) is presented to describe a reality. From health concerns to situations related with marketing, informatics or even sociology, several are ... More
Semiglobal exponential stabilization of nonautonomous semilinear parabolic-like systemsMar 18 2019It is shown that an explicit oblique projection nonlinear feedback controller is able to stabilize semilinear parabolic equations, with time-dependent dynamics and with a polynomial nonlinearity. The actuators are typically modeled by a finite number ... More
Asymptotics of the three dimensional Vlasov equation in the large magnetic field limitNov 22 2018We study the asymptotic behavior of solutions to the Vlasov equation in the presence of a strong external magnetic field. In particular we provide a mathematically rigorous derivation of the guiding-center approximation in the general three dimensional ... More
"Non-renormalization" without supersymmetryNov 03 2006Dec 19 2006The g_{YM} perturbed, non supersymmetric extension of the dual single matrix description of 1/2 BPS states, within the Hilbert space reduction to the oscillator subsector associated with chiral primaries is considered. This matrix model is described in ... More
Existence of non-trivial embeddings of Interval Exchange Transformations into Piecewise IsometriesJan 29 2019We prove that almost every interval exchange transformation, with an associated translation surface of genus $g\geq 2$, can be non-trivially and isometrically embedded in a family of piecewise isometries. In particular this proves the existence of invariant ... More
Asymptotic stability of Oseen vortices for a density-dependent incompressible viscous fluidNov 20 2006In the analysis of the long-time behaviour of two-dimensional incompressible viscous fluids, Oseen vortices play a major role as attractors of any homogeneous solution with integrable initial vorticity. As a first step in the study of the density-dependent ... More
Weighted geometric inequalities for hypersurfaces in sub-static manifoldsFeb 19 2019We prove two weighted geometric inequalities that hold for strictly mean convex and star-shaped hypersurfaces in Euclidean space. The first one involves the weighted area and the area of the hypersurface and also the volume of the region enclosed by the ... More
De Alfaro, Fubini and Furlan from multi Matrix SystemsSep 22 2015Oct 20 2015We consider the quantum mechanics of an even number of space indexed hermitian matrices. Upon complexification, we show that a closed subsector naturally parametrized by a matrix valued radial coordinate has a description in terms of non interacting $s$-state ... More
Solutions for linear conservation laws with gradient constraintsFeb 03 2015We consider variational inequality solutions with prescribed gradient constraints for first order linear boundary value problems. For operators with coefficients only in $L^2$, we show the existence and uniqueness of the solution by using a combination ... More
States and quantum effects in the collective field theory of a deformed matrix modelJun 27 1993We derive an equation which gives the tree-level scattering amplitudes for tachyons in the black hole background using the exact states of the collective field hamiltonian corresponding to a deformed matrix model recently proposed by Jevicki and Yoneya. ... More
Non supersymmetric strong coupling background from the large N quantum mechanics of two matrices coupled via a Yang-Mills interactionJul 28 2008We derive the planar large N non-supersymmetric background of the quantum mechanical hamiltonian of two hermitean matrices coupled via a Yang-Mills interaction, in terms of the density of eigenvalues of one of the matrices. This background satisfies an ... More
Transverse momentum dependence in gluon distribution and fragmentation functionsSep 29 2000Mar 16 2001We investigate the twist two gluon distribution functions for spin 1/2 hadrons, emphasizing intrinsic transverse momentum of the gluons. These functions are relevant in leading order in the inverse hard scale in scattering processes such as inclusive ... More
On a constrained reaction-diffusion system related to multiphase problemsNov 18 2007We solve and characterize the Lagrange multipliers of a reaction-diffusion system in the Gibbs simplex of R^{N+1} by considering strong solutions of a system of parabolic variational inequalities in R^N. Exploring properties of the two obstacles evolution ... More
Dynamic and structural properties of orthorhombic rare-earth manganites under high pressureFeb 27 2014We report a high-pressure study of orthorhombic rare-earth manganites AMnO3 using Raman scattering (for A = Pr, Nd, Sm, Eu, Tb and Dy) and synchrotron X-ray diffraction (for A = Pr, Sm, Eu, and Dy). In all cases, a structural and insulator-to-metal transition ... More
Structural and insulator-to-metal phase transition at 50 GPa in GdMnO3Nov 21 2011We present a study of the effect of very high pressure on the orthorhombic perovskite GdMnO3 by Raman spectroscopy and synchrotron x-ray diffraction up to 53.2 GPa. The experimental results yield a structural and insulator-to-metal phase transition close ... More
Spin-polarized transport in ferromagnetic multilayered semiconductor nanostructuresOct 10 2006The occurrence of inhomogeneous spin-density distribution in multilayered ferromagnetic diluted magnetic semiconductor nanostructures leads to strong dependence of the spin-polarized transport properties on these systems. The spin-dependent mobility, ... More
Outflows from dwarf starbursts are ubiquitous: kinematics of z<0.3 GRB-SN hosts resolved with FLAMESApr 11 2019The hosts of long duration gamma-ray bursts are predominantly starburst galaxies at subsolar metallicity. At redshifts z<1, this implies that most of them are low-mass dwarf galaxies similar to the populations of blue compact dwarfs and dwarf irregulars. ... More
A parametric study on window-to-floor ratio of double window glazing and its shadowing using dynamic simulationApr 15 2015When incorrectly designed, windows can be responsible for unnecessary energy consumption in a building. This may result from its dimensions, orientation and shadowing. In a moderate climate like the Portuguese, and considering an annual thermal comfort ... More
Satellite rings and normal modes in rotating clouds of ultra cold atomsJun 23 2014Jul 29 2014The multiple scattering of light in a gas of ultra cold atoms is responsible for many exciting features observed in magneto-optical traps including the collective behavior forced by a Coulomb like potential. This field also induces plasma like phenomena ... More
Characterization of the second- and third-harmonic optical susceptibilities of atomically thin tungsten diselenideMar 05 2018Jan 04 2019We report the first detailed characterization of the sheet third-harmonic optical susceptibility, $\chi_{s}^{(3)}$, of tungsten diselenide (WSe$_{2}$). With a home-built confocal microscope setup developed to study harmonics generation, we map the second- ... More
Tunable room-temperature ferromagnet using an iron-oxide and graphene oxide nanocompositeMar 03 2015Magnetic materials have found wide application ranging from electronics and memories to medicine. Essential to these advances is the control of the magnetic order. To date, most room-temperature applications have a fixed magnetic moment whose orientation ... More
Anisotropic Boltzmann-Gibbs dynamics of strongly magnetized Vlasov-Fokker-Planck equationsOct 17 2016Dec 13 2018We consider various sets of Vlasov-Fokker-Planck equations modeling the dynamics of charged particles in a plasma under the effect of a strong magnetic field. For each of them in a regime where the strength of the magnetic field is effectively stronger ... More
Rotational deviations and invariant pseudo-foliations for periodic point free torus homeomorphismsApr 16 2017Mar 11 2018This article deals with directional rotational deviations for non-wandering periodic point free homeomorphisms of the 2-torus which are homotopic to the identity. We prove that under mild assumptions, such a homeomorphism exhibits uniformly bounded rotational ... More
Specification properties and thermodynamical properties of semigroup actionsFeb 04 2015May 08 2016In the present paper we study the thermodynamical properties of finitely generated continuous subgroup actions. We address a notion of topological entropy and pressure functions that does not depend on the growth rate of the semigroup and introduce strong ... More
Approximate controllability for Navier--Stokes equations in $\mathrm{3D}$ rectangles under Lions boundary conditionsDec 13 2017The $\mathrm{3D}$ Navier--Stokes system, under Lions boundary conditions, is proven to be approximately controllable provided a suitable saturating set does exist. An explicit saturating set for $\mathrm{3D}$ rectangles is given.
Variational and Quasi-Variational Inequalities with Gradient Type ConstraintsSep 06 2018This survey on stationary and evolutionary problems with gradient constraints is based on developments of monotonicity and compactness methods applied to large classes of scalar and vectorial solutions to variational and quasi-variational inequalities. ... More
PCIe Hot Plug support standardization challenges in ATCAJun 22 2018Throughout the last decade, the Advanced Telecommunications Computing Architecture (ATCA) solidified its position as one of the main switched-based crate standards for advanced Physics instrumentation, offering not only highly performant characteristics ... More
Quasivariational solutions for first order quasilinear equations with gradient constraintJan 30 2012We prove the existence of solutions for an evolution quasi-variational inequality with a first order quasilinear operator and a variable convex set, which is characterized by a constraint on the absolute value of the gradient that depends on the solution ... More
How universal is the Wigner distribution?Jul 19 2011Aug 23 2011We consider Gaussian ensembles of m N x N complex matrices. We identify an enhanced symmetry in the system and the resultant closed subsector, which is naturally associated with the radial sector of the theory. The density of radial eigenvalues is obtained ... More
Laplacians in polar matrix coordinates and radial fermionization in higher dimensionsNov 15 2009We consider the quantum mechanical hamiltonian of two, space indexed, hermitean matrices. By introducing matrix valued polar coordinates, we obtain the form of the laplacian acting on invariant states. For potentials depending only on the eigenvalues ... More
Quark Distribution Functions in a Diquark Spectator ModelFeb 07 1997The representation of quark distribution functions in terms of nonlocal operators is combined with a simple diquark spectator model. This allows us to estimate these functions for the nucleon ensuring correct crossing and support properties.
Large-time asymptotic stability of Riemann shocks of scalar balance lawsOct 19 2018We prove the large-time asymptotic orbital stability of strictly entropic Riemann shock solutions of first order scalar hyperbolic balance laws, under piecewise regular perturbations provided that the source term is dissipative about endstates of the ... More
Gevrey regularity for Navier--Stokes equations under Lions boundary conditionsAug 08 2016Aug 16 2016The Navier--Stokes system is considered in a compact Riemannian manifold. Gevrey class regularity is proven under Lions boundary conditions: in 2D for the Rectangle, Cylinder, and Hemisphere, and in 3D for the Rectangle. The cases of the 2D Sphere and ... More
Increasing powers in a degenerate parabolic logistic equationJun 26 2012The purpose of this paper is to study the asymptotic behavior of the positive solutions of the problem $$ \partial_t u-\Delta u=a u-b(x) u^p \text{in} \Omega\times \R^+, u(0)=u_0, u(t)|_{\partial \Omega}=0 $$ as $p\to +\infty$, where $\Omega$ is a bounded ... More
Clustering Algorithms: A Comparative ApproachDec 26 2016Many real-world systems can be studied in terms of pattern recognition tasks, so that proper use (and understanding) of machine learning methods in practical applications becomes essential. While a myriad of classification methods have been proposed, ... More
Complex Network Tools to Understand the Behavior of Criminality in Urban AreasDec 19 2016Dec 24 2016Complex networks are nowadays employed in several applications. Modeling urban street networks is one of them, and in particular to analyze criminal aspects of a city. Several research groups have focused on such application, but until now, there is a ... More
On the Two Obstacles Problem in Orlicz-Sobolev Spaces and ApplicationsMar 08 2010We prove the Lewy-Stampacchia inequalities for the two obstacles problem in abstract form for T-monotone operators. As a consequence for a general class of quasi-linear elliptic operators of Ladyzhenskaya-Uraltseva type, including p(x)-Laplacian type ... More
Block Conjugacy of Irreducible Toral AutomorphismsNov 03 2015We introduce a relation of block conjugacy for irreducible toral automorphism, and prove that block conjugacy is equivalent to weak equivalence of the ideals associated to the automorphisms. We characterize when block conjugate automorphisms are actually ... More
Measuring the continuum polarization with ESPaDOnSJun 03 2014Dec 05 2014Our goal is to test the feasibility to obtain accurate measurements of the continuum polarization from high-resolution spectra using the spectropolarimetric mode of ESPaDOnS. We used the new pipeline OPERA to reduce recent and archived ESPaDOnS data. ... More
Viral marketing as epidemiological modelJul 24 2015In epidemiology, an epidemic is defined as the spread of an infectious disease to a large number of people in a given population within a short period of time. In the marketing context, a message is viral when it is broadly sent and received by the target ... More
The Bundles of Algebraic and Dirac-Hestenes Spinor FieldsDec 10 2002Jun 15 2004The main objective of this paper is to clarify the ontology of Dirac-Hestenes spinor fields (DHSF) and its relationship with sum of even multivector fields, on a general Riemann-Cartan spacetime admitting a spin structure and to give a mathematically ... More
Diffeomorphism Invariance and Local Lorentz InvarianceOct 06 2005Oct 06 2005We show that diffeomorphism invariance of the Maxwell and the Dirac-Hestenes equations implies the equivalence among different universe models such that if one has a linear connection with non-null torsion and/or curvature the others have also. On the ... More
Mass redistribution in variable mass systemsNov 18 2002Sep 23 2003We have developed an alternative formulation based on ${\bf F} = M {\bf a}$ rather than ${\bf F} = d{\bf P}/dt$ for studying variable mass systems. It is shown that ${\bf F} = M {\bf a}$ can be particularly useful in this context, as illustrated by various ... More
Matrix Model Maps in AdS/CFTJul 13 2005Sep 26 2005We discuss an extension of a map between between BPS states and free fermions. The extension involves states associated with a full two matrix problem which are constructed using a sequence of integral equations. A two parameter set of matrix model eigenstates ... More