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Results for "Jose L. Alba-Castro"

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Generalized Presentation Attack Detection: a face anti-spoofing evaluation proposalApr 12 2019Over the past few years, Presentation Attack Detection (PAD) has become a fundamental part of facial recognition systems. Although much effort has been devoted to anti-spoofing research, generalization in real scenarios remains a challenge. In this paper ... More
Shedding Light on the Asymmetric Learning Capability of AdaBoostJul 08 2015In this paper, we propose a different insight to analyze AdaBoost. This analysis reveals that, beyond some preconceptions, AdaBoost can be directly used as an asymmetric learning algorithm, preserving all its theoretical properties. A novel class-conditional ... More
Untangling AdaBoost-based Cost-Sensitive Classification. Part I: Theoretical PerspectiveJul 15 2015Jul 22 2016Boosting algorithms have been widely used to tackle a plethora of problems. In the last few years, a lot of approaches have been proposed to provide standard AdaBoost with cost-sensitive capabilities, each with a different focus. However, for the researcher, ... More
Abstract Certification of Global Non-Interference in Rewriting LogicJun 22 2010Non-interference is a semantic program property that assigns confidentiality levels to data objects and prevents illicit information flows from occurring from high to low security levels. In this paper, we present a novel security model for global non-interference ... More
Double-Base Asymmetric AdaBoostJul 08 2015Based on the use of different exponential bases to define class-dependent error bounds, a new and highly efficient asymmetric boosting scheme, coined as AdaBoostDB (Double-Base), is proposed. Supported by a fully theoretical derivation procedure, unlike ... More
Bright Fireballs Associated with the Potentially Hazardous Asteroid 2007LQ19Jun 25 2014We analyze here two very bright fireballs produced by the ablation in the atmosphere of two large meteoroids in 2009 and 2010. These slow-moving and deep-penetrating events were observed over Spain in the framework of our Spanish Fireball Network continuous ... More
On numbers $n$ dividing the $n$th term of a linear recurrenceOct 21 2010Feb 01 2011Here, we give upper and lower bounds on the count of positive integers $n\le x$ dividing the $n$th term of a nondegenerate linearly recurrent sequence with simple roots.
Magnetization dynamics of weakly interacting sub-100 nm square artificial spin icesOct 09 2017Artificial Spin Ice (ASI), consisting of a two dimensional array of nanoscale magnetic elements, provides a fascinating opportunity to observe the physics of out of equilibrium systems. Initial studies concentrated on the static, frozen state, whilst ... More
Near Earth Object 2012XJ112 as a source of bright bolides of achondritic natureFeb 03 2014We analyze the likely link between the recently discovered Near Earth Object 2012XJ112 and a bright fireball observed over the south of Spain on December 27, 2012. The bolide, with an absolute magnitude of -9 +- 1, was simultaneously imaged during the ... More
Microwave Photonics Parallel Quantum Key DistributionDec 15 2011The incorporation of multiplexing techniques used in Microwave Photonics to Quantum Key Distribution (QKD) systems bring important advantages enabling the simultaneous and parallel delivery of multiple keys between a central station and different end-users ... More
Generating the Structure of a Fuzzy Rule under UncertaintyFeb 20 2013The aim of this paper is to present a method for identifying the structure of a rule in a fuzzy model. For this purpose, an ATMS shall be used (Zurita 1994). An algorithm obtaining the identification of the structure will be suggested (Castro 1995). The ... More
Backward volume contraction for endomorphisms with eventual volume expansionMar 31 2004We consider smooth maps on compact Riemannian manifolds. We prove that under some mild condition of eventual volume expansion Lebesgue almost everywhere we have uniform backward volume contraction on every pre-orbit for Lebesgue almost every point.
Correlated wounded hot spots in proton-proton interactionsDec 19 2016May 31 2017We investigate the effect of non-trivial spatial correlations between proton constituents, considered in this work to be gluonic hot spots, on the initial conditions of proton-proton collisions from ISR to LHC energies, i.e. $\sqrt s\!=\!52.6,7000,13000$ ... More
Correlated gluonic hot spots meet symmetric cumulants data at LHC energiesJul 16 2018We present a systematic study on the influence of spatial correlations between the proton constituents, in our case gluonic hot spots, their size and their number on the symmetric cumulant SC(2,3), at the eccentricity level, within a Monte Carlo Glauber ... More
Trapping of a particle in a short-range harmonic potential wellAug 31 2012Eigenstates of a particle in a localized and unconfined harmonic potential well are investigated. Effects due to the variation of the potential parameters as well as certain results from asymptotic expansions are discussed.
Spinless bosons embedded in a vector Duffin-Kemmer-Petiau oscillatorJun 01 2011Some properties of minimal and nonminimal vector interactions in the Duffin-Kemmer-Petiau (DKP) formalism are discussed. The conservation of the total angular momentum for spherically symmetric nonminimal potentials is derived from its commutation properties ... More
On the bound-state spectrum of a nonrelativistic particle in the background of a short-ranged linear potentialMar 15 2010The nonrelativistic problem of a particle immersed in a triangular potential well, set forth by N.A. Rao and B.A. Kagali, is revised. It is shown that these researchers misunderstood the full meaning of the potential and obtained a wrong quantization ... More
Fermion localization on two-field thick branesAug 21 2010Feb 18 2011In a recent paper published in this journal, Almeida and collaborators [Phys. Rev. D \textbf{79}, 125022 (2009)] analyze the issue of fermion localization of fermions on a brane constructed from two scalar fields coupled with gravity (Bloch brane model). ... More
XNMR: A tool for knowledge bases explorationMar 13 2000XNMR is a system designed to explore the results of combining the well-founded semantics system XSB with the stable-models evaluator SMODELS. Its main goal is to work as a tool for fast and interactive exploration of knowledge bases.
Unsuitable use of spin and pseudospin symmetries with a pseudoscalar Cornell potentialAug 05 2014The concepts of spin and pseudospin symmetries has been used as mere rhetorics to decorate the pseudoscalar potential [Chin. Phys. B 22 090301 (2013)]. It is also pointed out that a more complete analysis of the bound states of fermions in a a pseudoscalar ... More
Relating pseudospin and spin symmetries through chiral transformation with tensor interactionNov 17 2012We address the behavior of the Dirac equation with scalar ($S$), vector ($V$) and tensor ($U$) interactions under the $\gamma^{5}$ discrete chiral transformation. Using this transformation we can obtain from a simple way solutions for the Dirac equation ... More
Corroborating the equivalence between the Duffin-Kemmer-Petiau and the Klein-Gordon and Proca equationsJul 16 2014Jul 22 2014It is shown that the Hamiltonian version of the Duffin-Kemmer-Petiau theory with electromagnetic coupling brings about a source term at the current. It is also shown that such a source term disappears from the scenario if one uses the correct physical ... More
Missing solution in a Cornell potentialSep 30 2013Missing bound-state solutions for fermions in the background of a Cornell potential consisting of a mixed scalar-vector-pseudoscalar coupling is examined. Charge-conjugation operation, degeneracy and localization are discussed.
Comment on "Wave functions for a Duffin-Kemmer-Petiau particle in a time-dependent potential"Mar 09 2010It is shown that the paper "Wave functions for a Duffin-Kemmer-Petiau particle in a time-dependent potential", by Merad and Bensaid [J. Math. Phys. 48, 073515 (2007)] is not correct in using inadvertently a non-Hermitian Hamiltonian in a formalism that ... More
Search for neutrino point sources with IceCube 22-stringsNov 25 2008The IceCube detector took data in its 22-string configuration in 2007-2008. This data has been analyzed to search for extraterrestrial point sources of neutrinos using several methods. Two main methods are discussed and compared here: the binned and the ... More
Symmetric cumulants as a probe of the proton substructure at LHC energiesJul 18 2017Jan 08 2018We present a systematic study of the normalized symmetric cumulants, NSC(n,m), at the eccentricity level in proton-proton interactions at $\sqrt s\!=\! 13$ TeV within a wounded hot spot approach. We focus our attention on the influence of spatial correlations ... More
Fitness Probability Distribution of Bit-Flip MutationSep 11 2013Bit-flip mutation is a common mutation operator for evolutionary algorithms applied to optimize functions over binary strings. In this paper, we develop results from the theory of landscapes and Krawtchouk polynomials to exactly compute the probability ... More
Very large scale characterization of graphene mechanical devices using a colorimetry techniqueMay 03 2018We use a scalable optical technique to characterize more than 21000 circular nanomechanical devices made out of suspended single- and double-layer graphene on cavities with different diameters ($D$) and depths ($g$). To maximize the contrast between suspended ... More
Interpretation of Vector-like Quark Searches: Heavy Gluons in Composite Higgs ModelsJul 20 2015Dec 01 2015Pair production of new vector-like quarks in pp collisions is considered model independent as it is usually dominated by QCD production. We discuss the interpretation of vector-like quark searches in the case that QCD is not the only relevant production ... More
Interpretation of vector-like quark searches: the case of a heavy gluon in composite Higgs models and vector-like quarksDec 15 2015Pair production of new vector-like quarks in $pp$ collisions is considered model independent as it is usually dominated by QCD production. Nonetheless, the presence of a new massive color octet (heavy gluon) in some composite Higgs models may modify the ... More
Spectral determinants and quantum theta functionsApr 22 2016It has been recently conjectured that the spectral determinants of operators associated to mirror curves can be expressed in terms of a generalization of theta functions, called quantum theta functions. In this paper we study the symplectic properties ... More
Measuring the Rényi entropies: An out-of-equilibrium protocol via the Jarzynski equalitySep 07 2016In recent years entanglement measures, such as the von Neumann and the R\'enyi entropies, provided a unique opportunity to access elusive feature of quantum many-body systems. However, extracting entanglement properties analytically, experimentally, or ... More
Eigenstate thermalization hypothesis (ETH) and integrability in quantum spin chainsSep 22 2014Apr 20 2015We investigate the eigenstate thermalization hypothesis (ETH) in integrable models, focusing on the spin-1/2 isotropic Heisenberg (XXX) chain. We provide numerical evidence that ETH holds for typical eigenstates (weak ETH scenario). Specifically, using ... More
Out-of-equilibrium protocol for Rényi entropies via the Jarzynski equalitySep 07 2016Jun 30 2017In recent years entanglement measures, such as the von Neumann and the R\'enyi entropies, provided a unique opportunity to access elusive feature of quantum many-body systems. However, extracting entanglement properties analytically, experimentally, or ... More
Scattering of a proton with the Li4 cluster: non-adiabatic molecular dynamics description based on time-dependent density-functional theoryMar 28 2011We have employed non-adiabatic molecular dynamics based on time-dependent density-functional theory to characterize the scattering behaviour of a proton with the Li$_4$ cluster. This technique assumes a classical approximation for the nuclei, effectively ... More
Finding the most variable stars in the Orion Belt with the All Sky Automated SurveyJan 05 2010We look for high-amplitude variable young stars in the open clusters and associations of the Orion Belt. We use public data from the ASAS-3 Photometric V-band Catalogue of the All Sky Automated Survey, infrared photometry from the 2MASS and IRAS catalogues, ... More
Simulating the Generalized Gibbs Ensemble (GGE): a Hilbert space Monte Carlo approachJul 24 2015By combining classical Monte Carlo and Bethe ansatz techniques we devise a numerical method to construct the Truncated Generalized Gibbs Ensemble (TGGE) for the spin-1/2 isotropic Heisenberg ($XXX$) chain. The key idea is to sample the Hilbert space of ... More
Towards a Generalized Hydrodynamics description of Rényi entropies in integrable systemsJul 04 2018Feb 10 2019We investigate the steady-state R\'enyi entanglement entropies after a quench from a piecewise homogeneous initial state in integrable models. In the quench protocol two macroscopically different chains (leads) are joined together at the initial time, ... More
Thermal photon-IMF anticorrelation: a signal of prompt multifragmentation?Jul 22 2005The mechanism responsible for IMF emission in central $^{58}$Ni + $^{197}$Au reactions at 30 and 45 MeV/nucleon is investigated by looking at the thermal bremsstrahlung photon production. An IMF - photon anticorrelation signal is observed, for central ... More
Generalization of the Deutsch algorithm using two quditsJul 29 2004Sep 13 2004Deutsch's algorithm for two qubits (one control qubit plus one auxiliary qubit) is extended to two $d$-dimensional quantum systems or qudits for the case in which $d$ is equal to $2^n$, $n=1,2,...$ . This allows one to classify a certain oracle function ... More
Local hidden-variable models and negative-probability measuresOct 26 2000Dec 13 2000Elaborating on a previous work by Han et al., we give a general, basis-independent proof of the necessity of negative probability measures in order for a class of local hidden-variable (LHV) models to violate the Bell-CHSH inequality. Moreover, we obtain ... More
Degree of entanglement for two qutrits in a pure stateMay 08 2003In this paper, a new measure of entanglement for general pure bipartite states of two qutrits is formulated.
The Causal Boundary of spacetimes revisitedAug 11 2006Sep 06 2007We present a new development of the causal boundary of spacetimes, originally introduced by Geroch, Kronheimer and Penrose. Given a strongly causal spacetime (or, more generally, a chronological set), we reconsider the GKP ideas to construct a family ... More
Curve Singularities and Monster / Semple TowersDec 15 2009In earlier work, we introduced the `Monster tower', a tower of fibrations associated to planar curves. We constructed an algorithm for classifying its points with respect to the equivalence relation generated by the action of the contact pseudogroup on ... More
The Geometry of Radiative TransferJun 14 2012Jul 29 2013We present the geometry and symmetries of radiative transfer theory. Our geometrization exploits recent work in the literature that enables to obtain the Hamiltonian formulation of radiative transfer as the semiclassical limit of a phase space representation ... More
The equation of eigen-values in a general Euclidean Schwarzschild metricNov 16 2006A metric more general than the Euclidean Schwarzschild-Tangherlini metric is considered. The cosmological constant is not necessarily Zero, and the hypersphere is replaced by an Einstein variety. A differential equation that derives from the equation ... More
Non-singlet Q-deformed N=(1,0) and N=(1,1/2) U(1) actionsMay 18 2006Jun 20 2006In this paper we construct N=(1,0) and N=(1,1/2) non-singlet Q-deformed supersymmetric U(1) actions in components. We obtain an exact expression for the enhanced supersymmetry action by turning off particular degrees of freedom of the deformation tensor. ... More
1/Nc Countings in BaryonsMay 31 2004Jun 28 2004The $1/N_c$ power countings for baryon decays and configuration mixings are determined by means of a non-relativistic quark picture. Such countings are expected to be robust under changes in the quark masses, and therefore valid as these become light. ... More
Quantum perfect correlations and Hardy's nonlocality theoremAug 12 1999In this paper the failure of Hardy's nonlocality proof for the class of maximally entangled states is considered. A detailed analysis shows that the incompatibility of the Hardy equations for this class of states physically originates from the fact that ... More
The Feynman integral as a limit of complex measuresJun 05 2009The fundamental solution of the Schr\"odinger equation for a free particle is a distribution. This distribution can be approximated by a sequence of smooth functions. It is defined for each one of these functions, a complex measure on the space of paths. ... More
The Einstein's linear equation of a space-time with a homogeneous section of low dimensionJan 13 2011The Einstein's linear equation of a small perturbation in a space-time with a homogeneous section of low dimension, is studied. For every harmonic mode of the horizon, there are two solutions which behave differently at large distance $r$. In the basic ... More
Hardy's nonlocality for generalized n-particle GHZ statesJan 20 2004Jun 24 2004In this paper we extend Hardy's nonlocality proof for two spin-1/2 particles [PRL 71 (1993) 1665] to the case of n spin-1/2 particles configured in the generalized GHZ state. We show that, for all n \geq 3, any entangled GHZ state violates the Bell inequality ... More
Hardy-type experiment for the maximally entangled state: Illustrating the problem of subensemble postselectionJan 11 2000By selecting a certain subensemble of joint detection events in a two-particle interferometer arrangement, a formal nonlocality contradiction of the Hardy type is derived for an ensemble of particle pairs configured in the maximally entangled state. It ... More
Identification of all Hardy-type correlations for two photons or particles with spin 1/2Jan 30 2001May 20 2001By using an alternative, equivalent form of the CHSH inequality and making extensive use of the experimentally testable property of physical locality we determine the 64 different Bell-type inequalities (each one involving four joint probabilities) into ... More
A random walker on a ratchetJul 01 2005We analyze a model for a walker moving on a ratchet potential. This model is motivated by the properties of transport of motor proteins, like kinesin and myosin. The walker consists of two feet represented as two particles coupled nonlinearly through ... More
Primarity of direct sums of Orlicz spaces and Marcinkiewicz spacesSep 15 2018Let $\mathbb{Y}$ be either an Orlicz sequence space or a Marcinkiewicz sequence space. We take advantage of the recent advances in the theory of factorization of the identity carried on in [R. Lechner, Subsymmetric weak* Schauder bases and factorization ... More
Wiener-Hopf plus Hankel operators on the real line with unitary and sectorial symbolsNov 05 2005Feb 21 2006Wiener-Hopf plus Hankel operators acting between Lebesgue spaces on the real line are studied in view of their invertibility, one sided-invertibility, Fredholm, and semi-Fredholm properties. This is done in two different cases: (i) when the Fourier symbols ... More
The Chains of Left-invariant CR-structures on SU(2)Nov 16 2007Jun 14 2008We compute the chains associated to the left-invariant CR structures on the three-sphere. These structures are characterized by a single real modulus $a$. For the standard structure $a=1$, the chains are well-known and are closed curves. We show that ... More
On measure expansive diffeomorphismsFeb 10 2013Let $f: M \to M$ be a diffeomorphism defined on a compact boundaryless $d$-dimensional manifold $M$, $d\geq 2$. C. Morales has proposed the notion of measure expansiveness. In this note we show that diffeomorphisms in a residual subset far from homoclinic ... More
An effective singular oscillator for Duffin-Kemmer-Petiau particles with a nonminimal vector coupling: a two-fold degeneracyJan 06 2012Scalar and vector bosons in the background of one-dimensional nonminimal vector linear plus inversely linear potentials are explored in a unified way in the context of the Duffin-Kemmer-Petiau theory. The problem is mapped into a Sturm-Liouville problem ... More
Inconsistencies of a purported probability current in the Duffin-Kemmer-Petiau theoryJun 02 2008Aug 05 2008The Duffin-Kemmer-Petiau (DKP) equation with a square step potential is used in a simple way with polymorphic purposes. It proves adequate to refuse a proposed new current that is currently interpreted as a probability current,to show that the Klein paradox ... More
Bounded solutions of fermions in the background of mixed vector-scalar Pöschl-Teller-like potentialsNov 15 2006The problem of a fermion subject to a convenient mixing of vector and scalar potentials in a two-dimensional space-time is mapped into a Sturm-Liouville problem. For a specific case which gives rise to an exactly solvable effective modified P\"{o}schl-Teller ... More
Absence of Klein's paradox for massive bosons coupled by nonminimal vector interactionsMay 04 2009Jul 30 2009A few properties of the nonminimal vector interactions in the Duffin-Kemmer-Petiau theory are revised. In particular, it is shown that the space component of the nonminimal vector interaction plays a peremptory role for confining bosons whereas its time ... More
On the nonminimal vector coupling in the Duffin-Kemmer-Petiau theory and the confinement of massive bosons by a linear potentialMay 14 2009Oct 15 2009Vector couplings in the Duffin-Kemmer-Petiau theory are revised. It is shown that minimal and nonminimal vector potentials behave differently under charge-conjugation and time-reversal transformations. In particular, it is shown that nonminimal vector ... More
Comment on "Solutions of the Duffin-Kemmer-Petiau equation for a pseudoscalar potential step in (1+1) dimensionsApr 14 2009It is shown that the paper "Solutions of the Duffin-Kemmer-Petiau equation for a pseudoscalar potential step in (1+1) dimensions" by Abdelmalek Boumali has a number of misconceptions.
Relativistic Effects of Mixed Vector-Scalar-Pseudoscalar Potentials for Fermions in 1+1 DimensionsOct 03 2007The problem of fermions in the presence of a pseudoscalar plus a mixing of vector and scalar potentials which have equal or opposite signs is investigated. We explore all the possible signs of the potentials and discuss their bound-state solutions for ... More
High energy astrophysical neutrino flux and modified dispersion relationsJul 11 2009Jul 13 2009Motivated by the interest in searches for violation of CPT invariance, we study its possible effects in the flavour ratios of high-energy neutrinos coming from cosmic accelerators. In particular, we focus on the effect of an energy independent new physics ... More
Measuring gravitational lens time delays using low-resolution radio monitoring observationsMar 19 2014Obtaining lensing time delay measurements requires long-term monitoring campaigns with a high enough resolution (< 1 arcsec) to separate the multiple images. In the radio, a limited number of high-resolution interferometer arrays make these observations ... More
Radio counterpart of the lensed sub-mm emission in the cluster MS0451.6-0305: new evidence for the merger scenarioOct 07 2009SMM J04542-0301 is an extended (~1 arcmin) sub-mm source located near the core of the cluster MS0451.6-0305. It has been suggested that part of its emission arises from the interaction between a LBG and two EROs at z~2.9 that are multiply-imaged. However, ... More
Topological phase transitions driven by non-Abelian gauge potentials in optical square latticesAug 03 2013Nov 18 2013We analyze a tight-binding model of ultracold fermions loaded in an optical square lattice and subjected to a synthetic non-Abelian gauge potential featuring both a magnetic field and a translationally invariant SU(2) term. We consider in particular the ... More
Search for neutrino flares from point sources with IceCubeAug 28 2009A time-dependent search for neutrino flares from pre-defined directions in the whole sky is presented. The analysis uses a time clustering algorithm combined with an unbinned likelihood method. This algorithm provides a search for significant neutrino ... More
Effects due to a scalar coupling on the particle-antiparticle production in the Duffin-Kemmer-Petiau theoryJul 31 2009Oct 15 2009The Duffin-Kemmer-Petiau formalism with vector and scalar potentials is used to point out a few misconceptions diffused in the literature. It is explicitly shown that the scalar coupling makes the DKP formalism not equivalent to the Klein-Gordon formalism ... More
Geodesic connectedness of multiwarped spacetimesSep 14 1999A new technique for the study of geodesic connectedness in a class of Lorentzian manifolds is introduced. It is based on arguments of Brouwer's topological degree for the solution of functional equations. It is shown to be very useful for multiwarped ... More
Highly-magnified, Multiply-imaged radio counterparts of the Sub-mm Starburst Emission in the Cluster-Lens MS0451.6-0305Mar 17 2006Nov 20 2006Previous authors have reported the detection of intrinsically faint sub-mm emission lensed by the cluster MS0451.6-0305. They suggest that this emission arises from a merging system composed of a Ly-break galaxy and a pair of extremely red objects which ... More
Processing Uncertainty and Indeterminacy in Information Systems success mappingDec 13 2005Dec 15 2005IS success is a complex concept, and its evaluation is complicated, unstructured and not readily quantifiable. Numerous scientific publications address the issue of success in the IS field as well as in other fields. But, little efforts have been done ... More
Envelopes and covers for groupsApr 12 2015Sep 04 2016We connect work done by Enochs, Rada and Hill in module approximation theory with work undertaken by several group theorists and algebraic topologists in the context of homotopical localization and cellularization of spaces. This allows one to consider ... More
Homology equivalences inducing an epimorphism on the fundamental group and Quillen's plus constructionJan 28 2003Quillen's plus construction is a topological construction that kills the maximal perfect subgroup of the fundamental group of a space without changing the integral homology of the space. In this paper we show that there is a topological construction that, ... More
The Pearcey integral in the highly oscillatory regionNov 17 2015We consider the Pearcey integral $P(x,y)$ for large values of $\vert y\vert$ and bounded values of $\vert x\vert$. The integrand of the Pearcey integral oscillates wildly in this region and the asymptotic saddle point analysis is complicated. Then we ... More
On The Intrinsic Diversity of Type II-Plateau SupernovaeJan 26 2015May 26 2015Hydrogen-rich Type II-Plateau supernovae exhibit correlations between the plateau luminosity $L_{\rm pl}$, the nickel mass $M_{\rm Ni}$, the explosion energy $E_{\rm exp}$, and the ejecta mass $M_{\rm ej}$. Using our global, self-consistent, multi-band ... More
Optimal average approximations for functions mapping in quasi-Banach spacesAug 28 2013In 1994, M. M. Popov [On integrability in F-spaces, Studia Math. no 3, 205-220] showed that the fundamental theorem of calculus fails, in general, for functions mapping from a compact interval of the real line into the lp-spaces for 0<p<1, and the question ... More
A Global Model of The Light Curves and Expansion Velocities of Type II-Plateau SupernovaeSep 08 2014Dec 10 2014We present a new self-consistent and versatile method that derives photospheric radius and temperature variations of Type II-Plateau supernovae based on their expansion velocities and photometric measurements. We apply the method to a sample of 26 well-observed, ... More
A Monster Tower Approach to Goursat Multi-FlagsJul 21 2011We consider here the problem of classifying orbits of an action of the dif- feomorphism group of 3-space on a tower of fibrations with P2-fibers that generalize the Monster Tower due to Montgomery and Zhitomirskii. As a corollary we give the first steps ... More
Does median filtering truly preserve edges better than linear filtering?Dec 14 2006Apr 20 2009Image processing researchers commonly assert that "median filtering is better than linear filtering for removing noise in the presence of edges." Using a straightforward large-$n$ decision-theory framework, this folk-theorem is seen to be false in general. ... More
A connection between cellularization for groups and spaces via two-complexesFeb 21 2007Oct 14 2007Let $M$ denote a two-dimensional Moore space (so $H_2(M; \Z) = 0$), with fundamental group $G$. The $M$-cellular spaces are those one can build from $M$ by using wedges, push-outs, and telescopes (and hence all pointed homotopy colimits). The question ... More
Deterministic site exchange cellular automata model for the spread of diseases in human settlementsApr 07 2000A cellular automata model that describes as limit cases of his parameters the spread of contagious diseases modeled by systems of ordinary or partial differential equations is developed. Periodic features of the behavior of human settlement are considered. ... More
Characterization of 1-quasi-greedy basesApr 16 2015We show that a (semi-normalized) basis in a Banach space is quasi-greedy with quasi-greedy constant equal to 1 if and only if it is unconditional with suppression-unconditional constant equal to 1.
Hyers-Ulam Stability of Bessel EquationsMay 17 2018May 21 2018We analyse different kinds of stabilities for the Bessel equation and for the modified Bessel equation with initial conditions. Sufficient conditions are obtained in order to guarantee Hyers-Ulam-Rassias, $\sigma$-semi-Hyers-Ulam and Hyers-Ulam stabilities ... More
Spelling Rules for the Monster/Semple TowerJul 07 2014We further study the incidence relations that arise from the various subtowers, known as Baby Monster, which exist within the $\mathbb{R}^{3}$-Monster Tower. This allows us to complete the $RVT$ class spelling rules. We also present a method of calculating ... More
Enumeration of $k$-Fibonacci Paths using Infinite Weighted AutomataDec 06 2013Aug 05 2014In this paper, we introduce a new family of generalized colored Motzkin paths, where horizontal steps are colored by means of $F_{k,l}$ colors, where $F_{k,l}$ is the $l$th $k$-Fibonacci number. We study the enumeration of this family according to the ... More
Homogenising differential operatorsNov 08 2012We consider the Weyl algebra A (=A_n(k)) and its Rees algebra B with respect to the Bernstein filtration. The homogenisation of a differential operator in A is an element in B. In this paper we establish the validity of the division theorem for homogenized ... More
Complete spelling rules for the Monster tower over three-spaceDec 01 2015Aug 13 2016The Monster tower, also known as the Semple tower, is a sequence of manifolds with distributions of interest to both differential and algebraic geometers. Each manifold is a projective bundle over the previous. Moreover, each level is a fiber compactified ... More
N=2 Super-Born-Infeld from Partially Broken N=3 Supersymmetry in d=4May 10 2004Jun 23 2004We employ the non-linear realization techniques to relate the N=1 chiral, and the N=2 vector multiplets to the Goldstone spin 1/2 superfield arising from partial supersymmetry breaking of N=2 and N=3 respectively. In both cases, we obtain a family of ... More
Factorization theory for Wiener-Hopf plus Hankel operators with almost periodic symbolsNov 05 2005Mar 03 2006A factorization theory is proposed for Wiener-Hopf plus Hankel operators with almost periodic Fourier symbols. We introduce a factorization concept for the almost periodic Fourier symbols such that the properties of the factors will allow corresponding ... More
Bridges Between Subriemannian Geometry and Algebraic GeometrySep 08 2014We consider how the problem of determining normal forms for a specific class of nonholonomic systems leads to various interesting and concrete bridges between two apparently unrelated themes. Various ideas that traditionally pertain to the field of algebraic ... More
Finite-time condensation in 1D Fokker-Planck model for bosonsJan 30 2019We consider a one-dimensional analogue of the three-dimensional Fokker-Planck equation for bosons. The latter is still only partially understood, and, in particular, the physically relevant question of whether this equation has solutions which form a ... More
Metropolis Monte Carlo algorithm based on the reparametrization invarianceJun 28 2006Nov 06 2006We introduce a modification of the well-known Metropolis importance sampling algorithm by using a methodology inspired on the consideration of the reparametrization invariance of the microcanonical ensemble. The most important feature of the present proposal ... More
Analysis of a superbolide from a Damocloid observed over Spain on July 13, 2012Oct 01 2013A superbolide with an estimated absolute magnitude of -20+-1 was seen on July 13, 2012 over the center and south of Spain. This extraordinary event, which was witnessed by numerous casual observers, was recorded in the framework of the continuous fireball ... More
Robust one-dimensionality at twin-grain-boundaries in MoSe$_{2}$Aug 08 2018Nov 12 2018We show that 1D electron states confined at twin-grain-boundaries in MoSe$_{2}$ can be modeled by a three-orbital tight binding model including a minimum set of phenomenological hopping terms. The confined states are robust to the details of the defect ... More
Lithium in M67: From the main sequence to the red giant branchMar 20 2012Apr 18 2012Lithium abundances in open clusters are a very effective probe of mixing processes, and their study can help to understand the large depletion of lithium in the Sun. Due to its age and metallicity, the open cluster M67 is especially interesting on this ... More