Results for "Luis Miguel Torres"

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On dominating set polyhedra of circular interval graphsDec 19 2017Feb 20 2018Clique-node and closed neighborhood matrices of circular interval graphs are circular matrices. The stable set polytope and the dominating set polytope on these graphs are therefore closely related to the set packing polytope and the set covering polyhedron ... More
Circuits and circulant minorsFeb 08 2019Circulant contraction minors play a key role for characterizing ideal circular matrices in terms of minimally non ideal structures. In this article we prove necessary and sufficient conditions for a circular matrix $A$ to have circulant contraction minors ... More
Topological Laminations on SurfacesMay 29 2018We present and prove a topological characterization of geodesic laminations on hyperbolic surfaces of finite type.
Vortex-like finite-energy asymptotic profiles for isentropic compressible flowsApr 10 2008Bidimensional incompressible viscous flows with well-localised vorticity are well-known to develop vortex structures. The purpose of the present paper is to recover the asymptotic profiles describing these phenomena for homogeneous finite-energy flows ... More
Robot Economy: Ready or Not, Here It ComesDec 04 2018Jan 20 2019Automation is not a new phenomenon, and questions about its effects have long followed its advances. More than a half-century ago, US President Lyndon B. Johnson established a national commission to examine the impact of technology on the economy, declaring ... More
Unveiling the dominant gas heating mechanism in local LIRGs and ULIRGsDec 17 2008We show preliminary results from a sample of Luminous and Ultra-Luminous Infrared Galaxies (LIRGs and ULIRGs, respectively) in the local universe, obtained from observations using the Very Large Array (VLA), the Multi-Element Radio Link Interferometer ... More
Constraint preserving boundary conditions for the Baumgarte-Shapiro-Shibata-Nakamura formulation in spherical symmetryJul 31 2014Nov 06 2014We introduce a set of constraint preserving boundary conditions for the Baumgarte-Shapiro-Shibata-Nakamura (BSSN) formulation of the Einstein evolution equations in spherical symmetry, based on its hyperbolic structure. While the outgoing eigenfields ... More
Gravitational collapse of charged scalar fieldsJul 29 2014In order to study the gravitational collapse of charged matter we analyze the simple model of an self-gravitating massless scalar field coupled to the electromagnetic field in spherical symmetry. The evolution equations for the Maxwell-Klein-Gordon sector ... More
On the geometry of pp-wave type spacetimesOct 01 2004Global geometric properties of product manifolds ${\cal M}= M \times \R^2$, endowed with a metric type $<\cdot, \cdot > = < \cdot, \cdot >_R + 2 dudv + H(x,u) du^2$ (where $<\cdot, \cdot >_R$ is a Riemannian metric on $M$ and $H:M \times \R \to \R$ a ... More
Compact affine manifolds with precompact holonomy are geodesically completeNov 11 2015Dec 21 2015This note proves the geodesic completeness of any compact manifold endowed with a linear connection such that the closure of its holonomy group is compact.
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
A Note on the WGC, Effective Field Theory and Clockwork within String TheorySep 07 2017It has been recently argued that Higgsing of theories with $U(1)^n$ gauge interactions consistent with the Weak Gravity Conjecture (WGC) may lead to effective field theories parametrically violating WGC constraints. The minimal examples typically involve ... More
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
Geodesics in stationary spacetimes. Application to Kerr spacetimeJun 20 2001Jan 11 2002The Levi-Civita connection and geodesic equations for a stationary spacetime are studied in depth. General formulae which generalize those for warped products are obtained. These results are applicated to some regions of Kerr spacetime previously studied ... More
The causal boundary of wave-type spacetimesDec 04 2007Feb 29 2008A complete and systematic approach to compute the causal boundary of wave-type spacetimes is carried out. The case of a 1-dimensional boundary is specially analyzed and its critical appearance in pp-wave type spacetimes is emphasized. In particular, the ... More
Large-time behavior of solutions to Vlasov-Poisson-Fokker-Planck equations: from evanescent collisions to diffusive limitJun 19 2017Nov 07 2017The present contribution investigates the dynamics generated by the two-dimensional Vlasov-Poisson-Fokker-Planck equation for charged particles in a steady inhomogeneous background of opposite charges. We provide global in time estimates that are uniform ... More
Infinite Interval Exchange Transformations from ShiftsJun 22 2015Nov 04 2015We show that minimal shifts with zero topological entropy are topologically conjugate to interval exchange transformations, generally infinite. When these shifts have linear factor complexity (linear block growth), the conjugate interval exchanges are ... More
Relevance Feedback in Conceptual Image Retrieval: A User EvaluationSep 28 2008The Visual Object Information Retrieval (VOIR) system described in this paper implements an image retrieval approach that combines two layers, the conceptual and the visual layer. It uses terms from a textual thesaurus to represent the conceptual information ... More
High-resolution radio observations of nuclear and circumnuclear starbursts in Luminous Infrared GalaxiesApr 27 2008High-resolution radio observations of nearby starburst galaxies have shown that the distribution of their radio emission consists of a compact (<150 pc), high surface brightness, central radio source immersed in a low surface brightness circumnuclear ... More
Dzyaloshinskii-Moriya interaction and magnetic ordering in 1D and 2D at nonzero $T$Mar 25 2014The inclusion of a Dzyaloshinskii-Moriya short range antisymmetric interaction induces spontaneous magnetization, at nonzero temperatures, in one and two dimensions. It is shown that quantum fluctuations are reduced by the Dzyaloshinskii-Moriya interaction, ... More
Conditionally Free Reduced Products of Hilbert SpacesFeb 07 2019We present a product of pairs of pointed Hilbert spaces that, in the context of Boz\.ejko, Leinert and Speicher's theory of conditionally free probability, plays the role of the reduced free product of pointed Hilbert spaces, and thus gives a unified ... More
A Versatile Framework for Robust and Adaptive Door Operation with a Mobile Manipulator RobotFeb 25 2019The ability to deal with articulated objects is very important for robots assisting humans. In this work a general framework for the robust operation of different types of doors using an autonomous robotic mobile manipulator is proposed. To push the state-of-the-art ... More
First-order invariants of differential 2-formsDec 18 2018Let $M$ be a smooth manifold of dimension $2n$, and let $O_{M}$ be the dense open subbundle in $\wedge^{2}T^{\ast}M$ of $2$-covectors of maximal rank. The algebra of $\operatorname*{Diff}M$-invariant smooth functions of first order on $O_{M}$ is proved ... More
The Classification Problem for 2-Forms in Four VariablesFeb 09 2018The notion of type of a differential 2-form in four variables is introduced and for 2-forms of type < 4, local normal models are given. If the type of a 2-form $\Omega$ is 4, then the equivalence under diffeomorphisms of $\Omega$ is reduced to the equivalence ... More
Sharp estimates for the arithmetic NullstellensatzNov 14 1999We present sharp estimates for the degree and the height of the polynomials in the Nullstellensatz over $\Z$. The result improves previous work of Philippon, Berenstein-Yger and Krick-Pardo. We also present degree and height estimates of intrinsic type, ... More
On the K-theory of feedback actions on linear systemsJun 05 2013A categorical approach to linear control systems is introduced. Feedback actions on linear systems arises as a symmetric monoidal category. Stable feedback isomorphisms generalize enlargement of pairs of matrices. Subcategory of locally Brunovsky linear ... More
On global solutions to some non-Markovian quantum kinetic models of Fokker-Planck typeNov 29 2018In this paper, global well-posedness of the non-Markovian Unruh-Zurek and Hu-Paz-Zhang master equations with nonlinear electrostatic coupling is demonstrated. They both consist of a Wigner-Poisson like equation subjected to a dissipative Fokker-Planck ... More
The Gardner equation and the L^2-stability of the N-soliton solution of the Korteweg-de Vries equationDec 23 2010Jan 22 2011Multi-soliton solutions of the Korteweg-de Vries equation (KdV) are shown to be globally L2-stable, and asymptotically stable in the sense of Martel-Merle. The proof is surprisingly simple and combines the Gardner transform, which links the Gardner and ... More
Fully nonlinear integro-differential equations with deforming kernelsSep 18 2018We develop a regularity theory for integro-differential equations with kernels deforming in space like sections of a convex solution of a Monge-Amp\`{e}re equation. We prove an ABP estimate and a Harnack inequality and derive H\"{o}lder and $C^{1,\alpha}$ ... More
Discrete conservation laws and the convergence of long time simulations of the mKdV equationSep 27 2011Pseudospectral collocation methods and finite difference methods have been used for approximating an important family of soliton like solutions of the mKdV equation. These solutions present a structural instability which make difficult to approximate ... More
On Detection Issues in the SC-based Uplink of a MU-MIMO System with a Large Number of BS AntennasFeb 19 2015This paper deals with SC/FDE within a MU-MIMO system where a large number of BS antennas is adopted. In this context, either linear or reduced-complexity iterative DF detection techniques are considered. Regarding performance evaluation by simulation, ... More
Weak value amplification: a view from quantum estimation theory that highlights what it is and what isn'tAug 08 2014Aug 12 2015Weak value amplification (WVA) is a concept that has been extensively used in a myriad of applications with the aim of rendering measurable tiny changes of a variable of interest. In spite of this, there is still an on-going debate about its true nature ... More
Rapidly-evolving episodic outflow in IRAS 18113-2503: clues to the ejection mechanism of the fastest water fountainSep 20 2018Oct 19 2018Water fountains are evolved stars showing early stages of collimated mass loss during transition from the asymptotic giant branch, providing valuable insight into the formation of asymmetric planetary nebulae. We report the results of multi-epoch VLBI ... More
A multi-wavelength view of the central kiloparsec region in the Luminous Infrared Galaxy NGC1614Mar 27 2014The Luminous Infrared Galaxy NGC1614 hosts a prominent circumnuclear ring of star formation. However, the nature of the dominant emitting mechanism in its central ~100 pc is still under debate. We present sub-arcsecond angular resolution radio, mid-infrared, ... More
The entropic origin of disassortativity in complex networksFeb 17 2010Why are most empirical networks, with the prominent exception of social ones, generically degree-degree anticorrelated, i.e. disassortative? With a view to answering this long-standing question, we define a general class of degree-degree correlated networks ... More
Segmentation of Dynamic Contrast-Enhanced Magnetic Resonance Images of the ProstateOct 10 2017Dynamic Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) is a valuable tool to localize, characterize, and evaluate anomalous prostate tissue. Ultrafast gradient-echo acquisitions of MRI volumes are generated at regular time intervals while the ... More
Radiated fields by polygonal core-shell nanowiresApr 21 2018We calculate the electromagnetic field radiated by tubular nanowires with prismatic geometry and infinite length. The polygonal geometry has implications on the electronic localization; the lowest energy states are localized at the edges of the prism ... More
Cosmological nonlinear structure formation in full general relativitySep 28 2014Nov 26 2014We perform numerical evolutions of cosmological scenarios using a standard general relativistic code in spherical symmetry. We concentrate on two different situations: initial matter distributions that are homogeneous and isotropic, and perturbations ... More
Network complexity and topological phase transitionsDec 18 2015A new type of collective excitations, due exclusively to the topology of a complex random network that can be characterized by a fractal dimension $D_F$, is investigated. We show analytically that these excitations generate phase transitions due to the ... More
EVN observations of the farthest and brightest ULIRGs in the local Universe: the case of IRAS 23365+3604Jan 24 2012We present high-resolution, high-sensitivity radio images of the ultra-luminous infrared galaxy (ULIRG) IRAS 23365+3604. We performed contemporaneous observations at 1.7 and 5.0 GHz, in three epochs separated by one year from each other, with the European ... More
EVN observations of the Ultra Luminous Infrared Galaxies IRAS 23365+3604 and IRAS 07251-0248Dec 03 2008We present high-sensitivity, high-resolution images of the Ultraluminous Infrared Galaxies (ULIRG; L$_{\mathrm{FIR}} > 10^{12}$ L$_\odot$) IRAS 23365+3604 and IRAS 07251-0248, taken with the EVN at 6 and 18 cm. The images show a large number of compact ... More
Topological complexity of motion planning in projective product spacesJun 01 2012We study Farber's topological complexity (TC) of Davis' projective product spaces (PPS's). We show that, in many non-trivial instances, the TC of PPS's coming from at least two sphere factors is (much) lower than the dimension of the manifold. This is ... More
Peptides as versatile scaffolds for quantum computingAug 30 2017Oct 03 2017In this work we showcase the potential of peptides as versatile scaffolds for quantum computing and molecular spintronics. In particular, we focus on lanthanide-binding tags, which were originally developed in the field of biotechnology for the study ... More
The Carnegie Supernova Project: Absolute Calibration and the Hubble ConstantSep 17 2018Sep 19 2018We present an analysis of the final data release of the Carnegie Supernova Project I, focusing on the absolute calibration of the luminosity-decline-rate relation for Type Ia supernovae (SNeIa) using new intrinsic color relations with respect to the color-stretch ... More
Time resolution studies for scintillating plastics coupled to silicon photo-multipliersJan 15 2019We present results for time resolution studies performed on three different scintillating plastics and two silicon photo-multipliers. These studies are intended to determine whether scintillating plastic/silicon photo-multiplier systems can be employed ... More
Relaxion Monodromy and the Weak Gravity ConjectureNov 30 2015Jul 25 2016The recently proposed relaxion models require extremely large trans-Planckian axion excursions as well as a potential explicitly violating the axion shift symmetry. The latter property is however inconsistent with the axion periodicity, which corresponds ... More
Testing the nonlinear stability of Kerr-Newman black holesOct 02 2014Dec 09 2014The nonlinear stability of Kerr-Newman black holes (KNBHs) is investigated by performing numerical simulations within the full Einstein-Maxwell theory. We take as initial data a KNBH with mass $M$, angular momentum to mass ratio $a$ and charge $Q$. Evolutions ... More
Study on Resource Efficiency of Distributed Graph ProcessingMar 30 2017Graphs may be used to represent many different problem domains -- a concrete example is that of detecting communities in social networks, which are represented as graphs. With big data and more sophisticated applications becoming widespread in recent ... More
Predicting evolutionary rescue via evolving plasticity in stochastic environmentsSep 21 2016Phenotypic plasticity and its evolution may help evolutionary rescue in a novel and stressful environment, especially if environmental novelty reveals cryptic genetic variation that enables the evolution of increased plasticity. However, the environmental ... More
Periodic Geodesics and Geometry of Compact Lorentzian Manifolds with a Killing Vector FieldDec 05 2008Feb 25 2009We study the geometry and the periodic geodesics of a compact Lorentzian manifold that has a Killing vector field which is timelike somewhere. Using a compactness argument for subgroups of the isometry group, we prove the existence of one timelike non ... More
Collisions of oppositely charged black holesNov 25 2013Feb 07 2014The first fully non-linear numerical simulations of colliding charged black holes in D=4 Einstein-Maxwell theory were recently reported arXiv:1205.1063. These collisions were performed for black holes with equal charge-to-mass ratio, for which initial ... More
Harnessing synthetic gauge fields for maximally entangled state generationJan 21 2014We study the generation of entanglement between two species of neutral cold atoms living on an optical ring lattice, where each group of particles can be described by a $d$-dimensional Hilbert space (qu$d$it). Synthetic magnetic fields are exploited to ... More
Linear representations of convolutional codes over ringsJul 28 2016In this paper we extend the relation between convolutional codes and linear systems over finite fields to certain commutative rings through first order representations . We introduce the definition of rings with representations as those for which these ... More
On the first stability eigenvalue of constant mean curvature surfaces into homogeneous 3-manifoldsOct 15 2013We find out upper bounds for the first eigenvalue of the stability operator for compact constant mean curvature surfaces immersed into certain 3-dimensional Riemannian spaces, in particular into homogeneous 3-manifolds. As an application we derive some ... More
A comparison of eigenvalue condition numbers for matrix polynomialsApr 25 2018In this paper, we consider the different eigenvalue condition numbers for matrix polynomials used in the literature and we compare them. One of these condition numbers is a generalization of the Wilkinson condition number for the standard eigenvalue problem. ... More
Global hyperbolicity and Palais-Smale condition for action functionals in stationary spacetimesOct 05 2006In order to apply variational methods to the action functional for geodesics of a stationary spacetime, some hypotheses, useful to obtain classical Palais-Smale condition, are commonly used: pseudo-coercivity, bounds on certain coefficients of the metric, ... More
Hidden nonlinear su(2|2) superunitary symmetry of N=2 superextended 1D Dirac delta potential problemJul 10 2007Jan 10 2008We show that the N=2 superextended 1D quantum Dirac delta potential problem is characterized by the hidden nonlinear $su(2|2)$ superunitary symmetry. The unexpected feature of this simple supersymmetric system is that it admits three different $\mathbb ... More
The origin of the hidden supersymmetryApr 30 2010Sep 08 2010The hidden supersymmetry and related tri-supersymmetric structure of the free particle system, the Dirac delta potential problem and the Aharonov-Bohm effect (planar, bound state, and tubule models) are explained by a special nonlocal unitary transformation, ... More
Scaling Phenomena in Gravity from QCDNov 28 2006May 04 2007We present holographic arguments to predict properties of strongly coupled gravitational systems in terms of weakly coupled gauge theories. In particular we relate the latest computed value for the Choptuik critical exponent in black hole formation in ... More
Invariant Measures for a Stochastic Fokker-Planck EquationMar 26 2015Jun 18 2017We study the kinetic Fokker-Planck equation perturbed by a stochastic Vlasov force term. When the noise intensity is not too large, we solve the Cauchy Problem in a class of well-localized (in velocity) functions. We also show that, when the noise intensity ... More
A convex formulation for hyperspectral image superresolution via subspace-based regularizationNov 14 2014Hyperspectral remote sensing images (HSIs) usually have high spectral resolution and low spatial resolution. Conversely, multispectral images (MSIs) usually have low spectral and high spatial resolutions. The problem of inferring images which combine ... More
A Framework for Fast Image Deconvolution with Incomplete ObservationsFeb 03 2016Aug 30 2016In image deconvolution problems, the diagonalization of the underlying operators by means of the FFT usually yields very large speedups. When there are incomplete observations (e.g., in the case of unknown boundaries), standard deconvolution techniques ... More
Collisions of charged black holesMay 04 2012Jul 05 2012We perform fully non-linear numerical simulations of charged-black-hole collisions, described by the Einstein-Maxwell equations, and contrast the results against analytic expectations. We focus on head-on collisions of non-spinning black holes, starting ... More
An Extension of Averaged-Operator-Based AlgorithmsJun 12 2018Many of the algorithms used to solve minimization problems with sparsity-inducing regularizers are generic in the sense that they do not take into account the sparsity of the solution in any particular way. However, algorithms known as semismooth Newton ... More
Deep Speech Enhancement for Reverberated and Noisy Signals using Wide Residual NetworksJan 03 2019This paper proposes a deep speech enhancement method which exploits the high potential of residual connections in a wide neural network architecture, a topology known as Wide Residual Network. This is supported on single dimensional convolutions computed ... More
Geometric Realizability of Covariant Derivative Kähler Tensors for almost Pseudo-Hermitian and almost Para-Hermitian ManifoldsDec 22 2010The covariant derivative of the K\"ahler form of an almost pseudo-Hermitian or of an almost para-Hermitian manifold satisfies certain algebraic relations. We show, conversely, that any 3-tensor which satisfies these algebraic relations can be realized ... More
A 5 GHz LNA for a Radio-Astronomy ExperimentMar 03 2011The paper describes the project, implementation and test of a C-band (5GHz) Low Noise Amplifier (LNA) using new low noise Pseudomorphic High Electron Mobility Transistors (pHEMTS) from Avago. The amplifier was developed to be used as a cost effective ... More
Exotic supersymmetry of the kink-antikink crystal, and the infinite period limitDec 21 2010Apr 10 2011Some time ago, Thies et al. showed that the Gross-Neveu model with a bare mass term possesses a kink-antikink crystalline phase. Corresponding self-consistent solutions, known earlier in polymer physics, are described by a self-isospectral pair of one-gap ... More
Periodic generation and propagation of traveling fronts in dc voltage biased semiconductor superlatticesNov 28 1996The continuum limit of a recently-proposed model for charge transport in resonant-tunneling semiconductor superlattices is analyzed. It is described by a nonlinear hyperbolic integrodifferential equation on a one-dimensional spatial support, supplemented ... More
Stability of periodic waves in Hamiltonian PDEsDec 06 2013Partial differential equations endowed with a Hamiltonian structure, like the Korteweg--de Vries equation and many other more or less classical models, are known to admit rich families of periodic travelling waves. The stability theory for these waves ... More
Hyperspectral image superresolution: An edge-preserving convex formulationMar 31 2014Jun 10 2014Hyperspectral remote sensing images (HSIs) are characterized by having a low spatial resolution and a high spectral resolution, whereas multispectral images (MSIs) are characterized by low spectral and high spatial resolutions. These complementary characteristics ... More
Regularity for anisotropic fully nonlinear integro-differential equationsNov 04 2013We consider fully nonlinear integro-differential equations governed by kernels that have different homogeneities in different directions. We prove a nonlocal version of the ABP estimate, a Harnack inequality and the interior $C^{1, \gamma}$ regularity, ... More
On Bezout Inequalities for non-homogeneous Polynomial IdealsJan 16 2017We introduce a "workable" notion of degree for non-homogeneous polynomial ideals and formulate and prove ideal theoretic B\'ezout Inequalities for the sum of two ideals in terms of this notion of degree and the degree of generators. We compute probabilistically ... More
Conditioning and backward errors of eigenvalues of homogeneous matrix polynomials under Möbius transformationsOct 26 2018M\"{o}bius transformations have been used in numerical algorithms for computing eigenvalues and invariant subspaces of structured generalized and polynomial eigenvalue problems (PEPs). These transformations convert problems with certain structures arising ... More
A note on the kernel of a pair of linear mapsMar 08 2016The kernel of a pair of linear systems is studied in the framework of commutative ring theory with applications to behavioral perspective of linear systems
Observation of spectral interference for any path difference in an interferometerApr 05 2014We report the experimental observation of spectral interference in a Michelson interferometer, regardless of the relationship between the temporal path difference introduced between the arms of the interferometer and the spectral width of the input pulse. ... More
The photo-disintegration of $^4$He on the cosmic microwave background is less severe than earlier thoughtMay 01 2018Jul 19 2018We thoroughly study the photo-disintegration of $^4$He on the cosmic microwave background using the most recent cross-section data both from the inclusive measurement observing the analog of the giant dipole resonance in $^4$He through the charge-exchange ... More
Observation of the full spiral spectrum of a light beam with single-pixel detectionAug 14 2017We demonstrate experimentally a simple and easy-to-use technique aimed at measuring the complex orbital angular momentum spectrum of an arbitrary optical field making use of just polarization measurements. The technique can be applied to any other family ... More
[Regularity of interfaces for a Pucci type segregation problemMar 09 2018We show the existence of a Lipschitz viscosity solution $u$ in $\Omega$ to a system of fully nonlinear equations involving Pucci-type operators. We study the regularity of the interface $\partial \{ u> 0 \}\cap\Om$ and we show that the viscosity inequalities ... More
Vacuum static Brans-Dicke wormholeJul 10 1997A simple Lorentzian vacuum wormhole solution of Brans-Dicke gravitation is presented and analysed. It is shown that such solution holds for both, the Brans-Dicke theory endowed with torsion (for a value of the coupling parameter $\omega > 1/2$) and for ... More
How to automate a kinematic mount using a 3D printed Arduino-based systemMar 17 2018We demonstrate a simple, flexible and cost-effective system to automatize most of the kinematic mounts available nowadays on the market. It combines 3D printed components, an Arduino board, stepper motors, and simple electronics. The system developed ... More
Radiation from a uniformly accelerated charge in the outskirts of a wormhole throatNov 27 2000Using traversable wormholes as theoretical background, we revisit a deep question of general relativity: Does a uniformly accelerated charged particle radiate? We particularize to the recently proposed gravitational \v{C}erenkov radiation, that happens ... More
Testing the Correlation of Ultra-High Energy Cosmic Rays with High Redshift SourcesAug 23 2000Dec 04 2000We study the correlation between compact radio quasars or 3EG gamma-ray blazars and the arrival directions of cosmic rays above 10^19 eV using an updated list of air shower detections. Our Monte Carlo simulations reveal no significant correlations above ... More
Primordial Nucleosynthesis as a test of variable rest masses 5-dimensional cosmologyNov 20 1995Aug 01 1996The deviation of primordial Helium production due to a variation on the difference between the rest masses of the nucleons is presented. It is found an upper bound $\delta (M_{_n} - M_{_p}) \alt 0.129$ MeV, between the present and nucleosynthesis epochs. ... More
Tunable beam displacerMay 19 2014Jan 08 2015We report the implementation of a tunable beam displacer, composed of a polarizing beam splitter (PBS) and two mirrors, that divides an initially polarized beam into two parallel beams whose separation can be continuously tuned. The two output beams are ... More
Symmetry-adapted formulation of the combined G-particle-hole Hypervirial equation and Hermitian Operator methodDec 26 2013High accuracy energies of low-lying excited states, in molecular systems, have been determined by means of a procedure which combines the G-particle-hole Hypervirial (GHV) equation method [Alcoba et al. Int. J. Quantum Chem. 109:3178 (2009)] and the Hermitian ... More
Plackett-Burman experimental design for pulsed-DC-plasma deposition of DLC coatingsJul 15 2015The influence of technological parameters of pulsed-DC chemical vapour deposition on the deposition rate, the mechanical properties and the residual stress of diamond-like carbon (DLC) coatings deposited onto a martensitic steel substrate, using a Ti ... More
A beam-beam monitoring detector for the MPD experiment at NICASep 26 2018The Multi-Purpose Detector (MPD) is to be installed at the Nuclotron Ion Collider fAcility (NICA) of the Joint Institute for Nuclear Research (JINR). Its main goal is to study the phase diagram of the strongly interacting matter produced in heavy-ion ... More
The Carnegie Supernova Project I: Third Photometry Data Release of Low-Redshift Type Ia Supernovae and Other White Dwarf ExplosionsSep 15 2017Nov 07 2017We present final natural system optical (ugriBV) and near-infrared (YJH) photometry of 134 supernovae (SNe) with probable white dwarf progenitors that were observed in 2004-2009 as part of the first stage of the Carnegie Supernova Project (CSP-I). The ... More
No AGN evidence in NGC1614 from deep radio VLBI observationsMay 30 2017We present deep dual-band 5.0 and 8.4GHz European VLBI Network (EVN) observations of NGC1614, a local luminous infrared galaxy with a powerful circumnuclear starburst ring, and whose nuclear engine origin is still controversial. We aim at detecting and ... More
Serendipitous discovery of the long-sought AGN in Arp 299-AAug 26 2010Context: The dusty nuclear regions of luminous infra-red galaxies (LIRGs) are heated by either an intense burst of massive star formation, an active galactic nucleus (AGN), or a combination of both. Disentangling the contribution of each of those putative ... More
The Core-Collapse Supernova Rate in Arp299 RevisitedApr 11 2011We present a study of the CCSN rate in nuclei A and B1 of the luminous infrared galaxy Arp299, based on 11 years of Very Large Array monitoring of their radio emission at 8.4 GHz. Significant variations in the nuclear radio flux density can be used to ... More
Arp 299-A: More than "just" a prolific supernova factoryDec 21 2010We present partial results from our monitoring of the nuclear region of the starburst galaxy IC 694 (=Arp 299-A) at radio wavelengths, aimed at discovering recently exploded CCSNe, as well as to determine their rate of explosion, which carries crucial ... More
Cosmological scalar field perturbations can growJan 27 2015Sep 15 2015It has been argued that the small perturbations to the homogeneous and isotropic configurations of a canonical scalar field in an expanding universe do not grow. We show that this is not true in general, and clarify the root of the misunderstanding. We ... More
Geometric thermodynamics: black holes and the meaning of the scalar curvatureJul 21 2014Dec 11 2014In this paper we show that the vanishing of the scalar curvature of Ruppeiner-like metrics does not characterize the ideal gas. Furthermore, we claim through an example that flatness is not a sufficient condition to establish the absence of interactions ... More
Conductance features of core-shell nanowires determined by the internal geometryMay 28 2018Aug 15 2018We consider electrons in tubular nanowires with prismatic geometry and infinite length. Such a model corresponds to a core-shell nanowire with an insulating core and a conductive shell. In a prismatic shell the lowest energy states are localized along ... More
Emission line activity in type 2 quasars from the Sloan Digital Sky SurveyAug 29 2008We have compared the optical emission line ratios of type 2 quasars from Zakamska et al. with standard AGN photoionization model predictions, Seyfert 2s, HII galaxies, and narrow line FRII radio galaxies. Moderate to high ionization narrow line radio ... More
Self-organization without conservation: Are neuronal avalanches generically critical?Jan 19 2010Recent experiments on cortical neural networks have revealed the existence of well-defined avalanches of electrical activity. Such avalanches have been claimed to be generically scale-invariant -- i.e. power-law distributed -- with many exciting implications ... More
Influence of topology on the performance of a neural networkOct 09 2003We studied the computational properties of an attractor neural network (ANN) with different network topologies. Though fully connected neural networks exhibit, in general, a good performance, they are biologically unrealistic, as it is unlikely that natural ... More