Results for "Guillermo Suarez-Tangil"

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Eight Years of Rider Measurement in the Android Malware Ecosystem: Evolution and Lessons LearnedJan 24 2018Despite the growing threat posed by Android malware, the research community is still lacking a comprehensive view of common behaviors and trends exposed by malware families active on the platform. Without such view, the researchers incur the risk of developing ... More
A First Look at the Crypto-Mining Malware Ecosystem: A Decade of Unrestricted WealthJan 03 2019Illicit crypto-mining leverages resources stolen from victims to mine cryptocurrencies on behalf of criminals. While recent works have analyzed one side of this threat, i.e.: web-browser cryptojacking, only white papers and commercial reports have partially ... More
Smart Home Personal Assistants: A Security and Privacy ReviewMar 13 2019Smart Home Personal Assistants (SPA) are an emerging innovation that is changing the way in which home users interact with the technology. However, there are a number of elements that expose these systems to various risks: i) the open nature of the voice ... More
Smart Home Personal Assistants: A Security and Privacy ReviewMar 13 2019Mar 17 2019Smart Home Personal Assistants (SPA) are an emerging innovation that is changing the way in which home users interact with the technology. However, there are a number of elements that expose these systems to various risks: i) the open nature of the voice ... More
On the Origins of Memes by Means of Fringe Web CommunitiesMay 31 2018Sep 22 2018Internet memes are increasingly used to sway and manipulate public opinion. This prompts the need to study their propagation, evolution, and influence across the Web. In this paper, we detect and measure the propagation of memes across multiple Web communities, ... More
"You Know What to Do": Proactive Detection of YouTube Videos Targeted by Coordinated Hate AttacksMay 21 2018Over the years, the Web has shrunk the world, allowing individuals to share viewpoints with many more people than they are able to in real life. At the same time, however, it has also enabled anti-social and toxic behavior to occur at an unprecedented ... More
$τ$-tilting modules over one-point extensions by a projective moduleMay 20 2017Let $A$ be the one point extension of an algebra $B$ by a projective $B$-module. We prove that the extension of a given support $\tau$-tilting $B$-module is a support $\tau$-tilting $A$-module; and, conversely, the restriction of a given support $\tau$-tilting ... More
On the global dimension of the endomorphism algebra of a $τ$-tilting moduleSep 18 2018We find a relationship between the global dimension of an algebra $A$ and the global dimension of the endomorphism algebra of a $\tau$-tilting module, when $A$ is of finite global dimension. We show that, in general, the global dimension of the endomorphism ... More
Covariant vs. non-covariant quantum collapse: Proposal for an experimental testNov 29 2013Jan 16 2014Two alternative interpretations of the quantum collapse are proposed: a time-ordered and a timeless one. The time-ordered interpretation implies that the speed of light can be defined in an absolute way, while the timeless quantum collapse implies relativity ... More
Comment on "Quantum theory cannot be extended" [arXiv:1005.5173v1]: Falsification of non-covariant extensions requires the before-before experimentJul 04 2010The Suarez-Scarani model is a non-covariant (frame-dependent) relativistic (time-ordered causal) nonlocal extension of quantum theory, which is not refuted by the experiments proposed in Reference [arXiv:1005.5173v1]. The covariant extensions considered ... More
3rd grade English language learners making sense of soundOct 06 2012Despite the extensive body of research that supports scientific inquiry and argumentation as cornerstones of physics learning, these strategies continue to be virtually absent in most classrooms, especially those that involve students who are learning ... More
Physics as a Mechanism for Including ELLs in Classroom DiscourseJul 13 2013Sep 14 2013English Language Learners (ELLs) are frequently left on the periphery of classroom interactions. Due to misalignment of language skills, teachers and peers communicate with these students less often, decreasing the number of opportunities to engage. Exclusion ... More
Second Yamabe Constant on Riemannian ProductsMay 05 2015Let $(M^m,g)$ be a closed Riemannian manifold $(m\geq 2)$ of positive scalar curvature and $(N^n,h)$ any closed manifold. We study the asymptotic behaviour of the second Yamabe constant and the second $N-$Yamabe constant of $(M\times N,g+th)$ as $t$ goes ... More
The transiting exoplanet host star GJ 436: a test of stellar evolution models in the lower main sequence, and revised planetary parametersOct 25 2007Knowledge of the stellar parameters for the parent stars of transiting exoplanets is pre-requisite for establishing the planet properties themselves, and often relies on stellar evolution models. GJ 436, which is orbited by a transiting Neptune-mass object, ... More
The Sun's Interior Metallicity Constrained by NeutrinosMay 25 2006Observed solar neutrino fluxes are employed to constrain the interior composition of the Sun. Including the effects of neutrino flavor mixing, the results from Homestake, Sudbury, and Gallium experiments constrain the Mg, Si, and Fe abundances in the ... More
The Astrometric-Spectroscopic Binary System HIP 50796: An Overmassive CompanionOct 14 2005We report spectroscopic observations of the star HIP 50796, previously considered (but later rejected) as a candidate member of the TW Hya association. Our measurements reveal it to be a single-lined binary with an orbital period of 570 days and an eccentricity ... More
A double-lined spectroscopic orbit for the young star HD 34700Nov 07 2003We report high-resolution spectroscopic observations of the young star HD 34700, which confirm it to be a double-lined spectroscopic binary. We derive an accurate orbital solution with a period of 23.4877 +/- 0.0013 days and an eccentricity of e = 0.2501 ... More
The structure of smooth algebras in Kapranov's framework for noncommutative geometryFeb 22 2000In Kapranov, M. {\it Noncommutative geometry based on commutator expansions,} J. reine angew. Math {\bf 505} (1998) 73-118, a theory of noncommutative algebraic varieties was proposed. Here we prove a structure theorem for the noncommutative coordinate ... More
Some relationships between the geometry of the tangent bundle and the geometry of the Riemannian base manifoldDec 26 2009We compute the curvature tensor of the tangent bundle of a Riemannian manifold endowed with a natural metric and we get some relationships between the geometry of the base manifold and the geometry of the tangent bundle.
Run-1 Single-top measurements at CMSOct 18 2015The Run-1 of the LHC was very successful for single top physics. The main single top production mode, $t-$channel, is now well established. The $t-$channel cross-section was measured with unprecedented precision and $t-$channel events have been used for ... More
Mean and variance of first passage time in Markov chains with unknown parametersFeb 18 2019Mar 01 2019There are known expressions to calculate the moments of the first passage time in Markov chains. Nevertheless, it is commonly forgotten that in most applications the parameters of the Markov chain are constructed using estimates based upon empirical data ... More
Mean and variance of first passage time in Markov chains with unknown parametersFeb 18 2019There are known expressions to calculate the moments of the first passage time in Markov chains. Nevertheless, it is commonly forgotten that in most applications the parameters of the Markov chain are constructed using estimates based upon empirical data ... More
Effective Approaches to Batch Parallelization for Dynamic Neural Network ArchitecturesJul 08 2017We present a simple dynamic batching approach applicable to a large class of dynamic architectures that consistently yields speedups of over 10x. We provide performance bounds when the architecture is not known a priori and a stronger bound in the special ... More
Learning from history: Non-Markovian analyses of complex trajectories for extracting long-time behaviorJul 05 2014A number of modern sampling methods probe long time behavior in complex biomolecules using a set of relatively short trajectory segments. Markov state models (MSMs) can be useful in analyzing such data sets, but in particularly complex landscapes, the ... More
Ecological model of extinctionsSep 11 1996We present numerical results based on a simplified ecological system in evolution, showing features of extinction similar to that claimed for the biosystem on Earth. In the model each species consists of a population in interaction with the others, that ... More
The Exponential Map on the Cayley-Dickson algebrasMay 21 2004we study the exponential map for A_n = R^2^n, the Cayley_Dickson algebras for n bigher than 1,wich generalize the Complex exponential map to Quaternions,Octonions and so forth. As application,we show that the self-map of the unit sphere in A_n, S^(2^n)-1,given ... More
Cyclic homology of commutative algebras over general ground ringsJan 26 2000We consider commutative algebras and chain DG algebras over a fixed commutative ground ring $k$ as in the title. We are concerned with the problem of computing the cyclic (and Hochschild) homology of such algebras via free DG-resolutions $\Lambda V @>>> ... More
The Chemical Compositions of Stars with Planets: A ReviewSep 29 2006A number of trends among the properties of exoplanets have become evident in the years since the first one was announced in 1995. One particularly interesting trend began to emerge in 1997 -- the incidence of giant planets correlates with the metallicity ... More
The criticality of the Hantavirus infected phase at ZuniJul 02 2004A preliminary analysis of the temporal evolution of a population of \emph{Peromyscus maniculatus} infected with Hantavirus Sin Nombre is made. Ecological and epidemiological parameters are derived from the data, and they are used as inputs for the analytical ... More
Combining Astrometry and SpectroscopyDec 05 2003Orbital solutions for binary or multiple stellar systems that combine astrometry (e.g., position angles and angular separations) with spectroscopy (radial velocities) have important advantages over astrometric-only or spectroscopic-only solutions. In ... More
Algebraic v. topological K-theory: a friendly matchMar 24 2009These notes evolved from the lecture notes of a minicourse given in Swisk, the Sedano Winter School on K-theory held in Sedano, Spain, during the week January 22--27 of 2007, and from those of a longer course given in the University of Buenos Aires, during ... More
Monomorphisms between Cayley-Dickson AlgebrasDec 22 2005In this paper we study the algebra monomorphisms from A_m =R^(2^m) into A_n=R^(2^n) for 0<m<n where the A_k 's are the Cayley- Dickson algebras over the real numbers. We show that for m>2 there are many different types of monomorphisms and we describe ... More
Hopf construction map in higher dimensionsApr 07 2004In this paper, we study the zero set of the Hopf construction map F_n : A_n_ x A_n --> A_n x A_0 given by F_n (x, y) = (2xy, | y|^2 - |x|^2) for n >3 where A_n is the Cayley-Dickson algebra of dimension 2^n over the real numbers.
The change in the inclination angle of the non-eclipsing binary SS Lacertae: future eclipsesDec 29 2000Eclipses in the 14.4-day period double-lined binary SS Lac were observed photographically and visually early in the 20th century, but stopped some 50 or 60 years ago. This has been explained by the presence of a distant third star in the system, which ... More
Astrometric-spectroscopic determination of the absolute masses of the HgMn binary star Phi HerculisMar 08 2007The Mercury-Manganese star Phi Her is a well known spectroscopic binary that has been the subject of a recent study by Zavala et al. (2006), in which they resolved the companion using long-baseline interferometry. The total mass of the binary is now fairly ... More
De Rham and infinitesimal cohomology in Kapranov's model for noncommutative algebraic geometryFeb 16 2001The title refers to the nilcommutative or $NC$-schemes introduced by M. Kapranov in math.AG/9802041. The latter are noncommutative nilpotent thickenings of commutative schemes. We consider also the parallel theory of nil-Poisson or $NP$-schemes, which ... More
The obstruction to excision in K-theory and in cyclic homologyNov 08 2001Oct 03 2005Let $f:A \to B$ be a ring homomorphism of not necessarily unital rings and $I\triangleleft A$ an ideal which is mapped by f isomorphically to an ideal of B. The obstruction to excision in K-theory is the failure of the map between relative K-groups $K_*(A:I) ... More
Infinitesimal K-theoryJan 25 2000In this paper we study the fiber F of the rational Jones-Goodwillie character $$ F:=\hofiber(ch:K^\rat(A)@>>>HN^\rat(A)) $$ going from K-theory to negative cyclic homology of associative rings. We describe this fiber F in terms of sheaf cohomology. We ... More
The Planet Host Star Gamma Cephei: Physical Properties, the Binary Orbit, and the Mass of the Substellar CompanionSep 22 2006The bright K1 III-IV star gamma Cep has been reported previously to have a companion in a 2.5-yr orbit that is possibly substellar, and also has a stellar companion at a larger separation that has never been seen. Here we determine for the first time ... More
The Multiple System HD 27638Dec 09 2005We report spectroscopic observations of HD 27638B, the secondary in a visual binary in which the physically associated primary (separation approximately 19 arcsec) is a B9V star. The secondary shows strong Li 6708 absorption suggesting youth, and has ... More
Alternative elements in the Cayley-Dickson algebrasApr 21 2004An element a in A_n, the Cayley-Dickson algebra is alternative if (a,a,x)=0 for all x. In this paper we characterise such elements for n>3.To do so,we prove first the so called Yui's conjecture:For a and b pure elements in A_n. If (a,x,b)=0 for all x ... More
Constructing zero divisors in the higher dimensional Cayley-Dickson algebrasDec 22 2005In this paper we give new methods to construct zero divisors in A_n =R^(2^n) the Cayley_Dickson algebras over the real numbers, for n larger than 4, and we also relate the set of zero divisors in A_{n+1} with the Stiefel Manifold V_{2^n -1,2} for n>3. ... More
Monomial multiplicities in explicit formJan 10 2019Jan 26 2019In this article we give explicit descriptions of the multiplicities of some classes of monomial ideals. For instance, we give a formula for the multiplicities of all codimension 1 monomial ideals, and another formula for the multiplicities of almost complete ... More
Infinitary propositional relevant languages with absurditySep 21 2018Analogues of Scott's isomorphism theorem, Karp's theorem as well as results on lack of compactness and strong completeness are established for infinitary propositional relevant logics. An "interpolation theorem" (of a particular sort introduced by Barwise ... More
Monomial ideals with large projective dimensionOct 14 2017Let S be a polynomial ring in n variables, over an arbitrary field. We give the total, graded, and multigraded Betti numbers of S/M, for every monomial ideal M in S. We also give an explicit characterization of all monomial ideals M in S for which the ... More
A Revised Gyro-Age for M 67 from Kepler/K2-Campaign-5 Light CurvesSep 02 2016We revisit the photometric variability of stars in the M 67 field using Kepler/K2-Campaign-5 light curves. In our previous work, we limited the search area around M\,67 to that of a recent ground-based study. In the present work, we expand the search ... More
Interferometry and the Fundamental Properties of StarsJul 15 2011For many decades the determination of accurate fundamental parameters for stars (masses, radii, temperatures, luminosities, etc.) has mostly been the domain of eclipsing binary systems. That has begun to change as long-baseline interferometric techniques ... More
On the use of empirical bolometric corrections for starsAug 23 2010When making use of tabulations of empirical bolometric corrections for stars (BC_V), a commonly overlooked fact is that while the zero point is arbitrary, the bolometric magnitude of the Sun (Mbol_Sun) that is used in combination with such tables cannot ... More
Parent Stars of Extrasolar Planets - XIII. Additional Evidence for Li Abundance AnomaliesApr 02 2014We report the results of our analysis of new high resolution spectra of 37 late-F to early-G dwarf stars for the purpose of deriving their Li abundances. Most of the stars were selected from the large Valenti and Fischer compilation and had unknown Li ... More
Setting the Stage for Habitable PlanetsMar 26 2014Our understanding of the processes that are relevant to the formation and maintenance of habitable planetary systems is advancing at a rapid pace, both from observation and theory. The present review focuses on recent research that bears on this topic ... More
A formalism for the study of Natural Tensors Fields of type (0,2) on Manifolds and FibrationsDec 11 2008Dec 15 2009In order to study tensor fields of type (0,2) on manifolds and fibrations we introduce the notion of s-spaces. With the help of these objects we generalized the concept of natural tensor without making use of the theory of natural operators and differential ... More
Bases of Wormholes in Quantum CosmologyApr 24 1994We show that if the space of physical states spanned by the wormhole wave functions can be equipped with a Hilbert structure, such a Hilbert space must coincide with that of the Lorentzian gravitational system under consideration. The physical inner product ... More
Relative Chern characters for nilpotent idealsJul 11 2008Sep 17 2008If I is a nilpotent ideal in a $\mathbb{Q}$-algebra $A$, Goodwillie defined two isomorphisms from $K_*(A,I)$ to negative cyclic homology, $HN_*(A,I)$. One is the relative version of the absolute Chern character, and the other is defined using rational ... More
MHD Models of Planetary Nebulae: ReviewFeb 01 2002Hydrodynamical (HD) simulations played an important role in understanding the dynamics and shaping of Planetary Nebulae (PNe) in the past century. However, HD solutions are just a first order approach. The new millennium arrives with the generalized understanding ... More
Complex structures in generalized small worldsFeb 23 2001We propose a generalization of small world networks, in which the reconnection of links is governed by a function that depends on the distance between the elements to be linked. An adequate choice of this function lets us control the clusterization of ... More
Extent of the Immirzi Ambiguity in Quantum General RelativityMar 07 2002The Ashtekar-Barbero formulation of general relativity admits a one-parameter family of canonical transformations that preserves the expressions of the Gauss and diffeomorphism constraints. The loop quantization of the connection formalism based on each ... More
Detailed abundance analysis of 8 super-metal-rich star candidatesDec 16 2000We provide detailed abundance analyses of 8 candidate super-metal-rich stars. Five of them are confirmed to have [Fe/H] > 0.2 dex, the generally-accepted limit for super-metal-richness. Furthermore, we derive abundances of several elements and find that ... More
Photodissociation in proto-planetary nebulae. Hydrodynamical simulations and solutions for low-velocity multi-lobesSep 10 2010We explore the effects of photodissociation at the stages of post-asymptotic giant branch stars to find a mechanism able to produce multi-polar shapes. We perform two-dimensional gasdynamical simulations to model the effects of photodissociation in proto-planetary ... More
Science for Peace in the Benefit of Humankind. The Hippocratic Oath for Scientists conceptJun 17 2010This article shows the importance that has had the scientific research, the technological development and the innovation processes in increasing the lethality of the available weapons during the last century. A set of initiatives promoted by the scientific ... More
Statistical Compressed Sensing of Gaussian Mixture ModelsJan 30 2011A novel framework of compressed sensing, namely statistical compressed sensing (SCS), that aims at efficiently sampling a collection of signals that follow a statistical distribution, and achieving accurate reconstruction on average, is introduced. SCS ... More
Geometric interpretation of Thiemann's generalized Wick transformMay 13 1997Dec 11 1998In the Ashtekar and geometrodynamic formulations of vacuum general relativity, the Euclidean and Lorentzian sectors can be related by means of the generalized Wick transform discovered by Thiemann. For some vacuum gravitational systems in which there ... More
Is the Exponential of the Chern-Simons Action a Normalizable Physical State?Feb 17 1994We determine the wavefunction that corresponds to the exponential of the Chern-Simons action in a family of gravitational models provided with cosmological constant whose non-perturbative canonical quantization is completely known. We show that this wavefunction ... More
Reality Conditions in Nonperturbative Quantum CosmologySep 23 1993We carry out the nonperturbative canonical quantization of several types of cosmological models that have already been studied in the geometrodynamic formulation using the complex path-integral approach. We establish a relation between the choices of ... More
Absolute dimensions of the M-type eclipsing binary YY Geminorum (Castor C): a challenge to evolutionary models in the lower main-sequenceNov 08 2001We present new spectroscopic observations of the detached late-type double-lined eclipsing binary YY Gem, a member of the Castor sextuple system and one of the benchmarks for the comparison between observations and stellar evolution theory in the lower ... More
Universal Regularizers For Robust Sparse Coding and ModelingMar 15 2010Aug 03 2010Sparse data models, where data is assumed to be well represented as a linear combination of a few elements from a dictionary, have gained considerable attention in recent years, and their use has led to state-of-the-art results in many signal and image ... More
Cluster Algorithm Renormalization Group MethodNov 30 2009We present a self consistent method based on cluster algorithms and Renormalization Group on the lattice to study critical systems numerically. We illustrate it by means of the 2D Ising model. We compute the critical exponents $\nu$ and $\eta$ and the ... More
The dependence of convective core overshooting on stellar mass: reality check, and additional evidenceApr 04 2019Overshooting from the convective cores of stars more massive than about 1.2 M(Sun) has a profound impact on their subsequent evolution. And yet, the formulation of the overshooting mechanism in current stellar evolution models has a free parameter (f[ov] ... More
Poincare Series and instability of exponential mapsJun 08 2005We relate the properties of the postsingular set for the exponential family to the questions of stability. We calculate the action of the Ruelle operator for the exponential family. We prove that if the asymptotic value is a summable point and its orbit ... More
Classical realizability and arithmetical formulæMar 04 2014Apr 11 2015In this paper we treat the specification problem in classical realizability (as defined in [20]) in the case of arithmetical formul{\ae}. In the continuity of [10] and [11], we characterize the universal realizers of a formula as being the winning strategies ... More
Pointed Hopf algebras over non abelian groups with decomposable braidings, IMay 10 2019We describe all finite-dimensional pointed Hopf algebras whose infinitesimal braiding is a fixed Yetter-Drinfeld module decomposed as the sum of two simple objects: a point and the one of transpositions of the symmetric group in three letters. We give ... More
The dependence of convective core overshooting on stellar mass: Additional binary systems and improved calibrationApr 09 2018Many current stellar evolution models assume some dependence of the strength of convective core overshooting on mass for stars more massive than 1.1-1.2 solar masses, but the adopted shapes for that relation have remained somewhat arbitrary for lack of ... More
On the bit complexity of polynomial system solvingDec 22 2016We exhibit a probabilistic algorithm which solves a polynomial system over the rationals defined by a reduced regular sequence. Its bit complexity is roughly quadratic in the B\'ezout number of the system and linear in its bit size. Our algorithm solves ... More
Nonnegative Matrix Underapproximation for Robust Multiple Model FittingNov 04 2016In this work, we introduce the first algorithm to truly address the nonnegative matrix underapproximation (NMU) problem, i.e., nonnegative matrix factorization (NMF) with an additional underapproximation constraint. NMU results are interesting as, compared ... More
Fast L1-NMF for Multiple Parametric Model EstimationOct 18 2016In this work we introduce a comprehensive algorithmic pipeline for multiple parametric model estimation. The proposed approach analyzes the information produced by a random sampling algorithm (e.g., RANSAC) from a machine learning/optimization perspective, ... More
Involutions on the Algebra of Physical Observables From Reality ConditionsJun 20 1995Some aspects of the algebraic quantization programme proposed by Ashtekar are revisited in this article. It is proved that, for systems with first-class constraints, the involution introduced on the algebra of quantum operators via reality conditions ... More
CANONICAL QUANTIZATION OF CYLINDRICALLY SYMMETRIC MODELSApr 05 1995We carry out the canonical quantization of the Levi-Civit\`a family of static and cylindrical solutions. The reduced phase space of this family of metrics is proved to coincide with that corresponding to the Kasner model, including the associated symplectic ... More
Reality Conditions for Lorentzian and Euclidean Gravity in the Ashtekar FormulationNov 11 1993Using Ashtekar variables, we analyze Lorentzian and Euclidean gravity in vacuum up to a constant conformal transformation. We prove that the reality conditions are invariant under a Wick rotation of the time, and show that the compatibility of the algebra ... More
The zero divisors of the Cayley-Dickson algebras over the real numbersOct 08 1997In this paper we describe algebraically the zero divirsors of the Cayley- Dickson algebras $\a_{n}=\erre^{2^n}$ for $n \ge 4$ over the real numbers.
Fluid accretion onto relativistic stars and gravitational radiationAug 15 2004This article reports results from numerical simulations of the gravitational radiation emitted from nonrotating relativistic stars as a result of the axisymmetric accretion of layers of perfect fluid matter, shaped in the form of quadrupolar shells. We ... More
Rotating Relativistic Thin Disks as Sources of the Taub-NUT SolutionDec 11 2002Jun 14 2009Rotating disks with nonzero radial pressure and finite radius are studied. The models are based in the Taub-NUT metric and constructed using the well-known ``displace, cut and reflect'' method. We find that the disks are made of perfect fluids with constant ... More
A straightforward local-search optimization algorithm on the symmetric groupApr 29 2009Given a real objective function defined over the symmetric group, a direct local-search algorithm is proposed, and its complexity is estimated. In particular for an $n$-dimensional unit vector we are interested in the permutation isometry that acts on ... More
Counting on Beauty: The role of aesthetic, ethical, and physical universal principles for interstellar communicationJul 28 2008SETI researchers believe that the basic principles of our science and the science of extraterrestrial beings should be fundamentally the same, and we should be able to communicate with them by referring to those things we share, such as the principles ... More
Azimuthal instabilities of the Gribov-Levin-Ryskin equationJun 25 2016We introduce the phenomenology of elliptic flow in nuclear collisions, and argue that its scaling across energies, rapidities and system sizes could be suggestive of a QCD-based rather than a hydrodynamical explanation. As a hypothesis for such an explanation, ... More
Nonnegative Matrix Underapproximation for Robust Multiple Model FittingNov 04 2016Nov 14 2016In this work, we introduce a highly efficient algorithm to address the nonnegative matrix underapproximation (NMU) problem, i.e., nonnegative matrix factorization (NMF) with an additional underapproximation constraint. NMU results are interesting as, ... More
A Brief Introduction to Loop Quantum CosmologyJul 29 2009In recent years, Loop Quantum Gravity has emerged as a solid candidate for a nonperturbative quantum theory of General Relativity. It is a background independent theory based on a description of the gravitational field in terms of holonomies and fluxes. ... More
The dependence of convective core overshooting on stellar mass: reality check, and additional evidenceApr 04 2019Apr 11 2019Overshooting from the convective cores of stars more massive than about 1.2 M(Sun) has a profound impact on their subsequent evolution. And yet, the formulation of the overshooting mechanism in current stellar evolution models has a free parameter (f[ov] ... More
Discovery of the first Earth-sized planets orbiting a star other than our Sun in the Kepler-20 systemMay 10 2019Discovering other worlds the size of our own has been a long-held dream of astronomers. The transiting planets Kepler-20e and Kepler-20f, which belong to a multi-planet system, hold a very special place among the many groundbreaking discoveries of the ... More
Quantum Mechanics at Planck's scale and Density MatrixJun 18 2003Aug 12 2003In this paper Quantum Mechanics with Fundamental Length is chosen as Quantum Mechanics at Planck's scale. This is possible due to the presence in the theory of General Uncertainty Relations. Here Quantum Mechanics with Fundamental Length is obtained as ... More
Density matrix and dynamical aspects of Quantum Mechanics with Fundamental LengthNov 25 2002Aug 20 2003In this paper Quantum Mechanics with Fundamental Length is built as a deformation of Quantum Mechanics. To this aim an approach is used which does not take into account commutator deformation as usually it is done, but density matrix deformation. The ... More
When the optimal is not the best: parameter estimation in complex biological modelsNov 18 2010Background: The vast computational resources that became available during the past decade enabled the development and simulation of increasingly complex mathematical models of cancer growth. These models typically involve many free parameters whose determination ... More
A Differential Spectroscopic Analysis of 16 Cygni A and BJan 17 2001We utilize high-resolution, high signal-to-noise spectra to perform a differential analysis of Fe abundances in the common proper-motion pair 16 Cyg A and B. We confirm that both stars are slightly metal-rich compared to the Sun, and we show for the first ... More
The Fixed Initial Credit Problem for Energy Games with Partial-Observation is ACK-completeDec 14 2015Feb 14 2016In this paper we study two-player games with asymmetric partial-observation and an energy objective. Such games are played on a weighted graph by Eve, choosing actions, and Adam, selecting a transition labelled with the given action. Eve attempts to maintain ... More
Wormholes as Basis for the Hilbert Space in Lorentzian GravityMay 10 1994We carry out to completion the quantization of a Friedmann-Robertson-Walker model provided with a conformal scalar field, and of a Kantowski-Sachs spacetime minimally coupled to a massless scalar field. We prove that the Hilbert space determined by the ... More
Canonical Quantization of the Gowdy ModelApr 15 1997The family of Gowdy universes with the spatial topology of a three-torus is studied both classically and quantum mechanically. Starting with the Ashtekar formulation of Lorentzian general relativity, we introduce a gauge fixing procedure to remove almost ... More
Pile-up corrections in laser-driven pulsed x-ray sourcesNov 22 2016A formalism for treating the pile-up produced in laser-driven pulsed x-ray sources has been developed. It allows the direct use of x-ray spectroscopy without artificially decreasing the number of counts in the detector. The influence of the pile-up on ... More
Artinian algebras and differential formsJan 26 2000This article concerns commutative algebras over a field $k$ of characteristic zero which are finite dimensional as vectorspaces, and particularly those of such algebras which are graded. Here the term graded is applied to non-negatively graded algebras ... More
A comparative study of star formation processes in different environmentsAug 28 2009In this thesis we have identified two star formation sites for star formation in galaxies which differ widely in metal content. We conclude that `massive' star formation that occurs in a high density, high metallicity environment, like that encountered ... More
Statistical Compressive Sensing of Gaussian Mixture ModelsOct 20 2010A new framework of compressive sensing (CS), namely statistical compressive sensing (SCS), that aims at efficiently sampling a collection of signals that follow a statistical distribution and achieving accurate reconstruction on average, is introduced. ... More
Weak arithmetic equivalenceOct 11 2013Sep 12 2014Inspired by the invariant of a number field given by its zeta function, we define the notion of {\it weak arithmetic equivalence}, and show that under certain ramification hypothesis, this equivalence determines the local root numbers of the number field. ... More
On number fields with equivalent integral trace formsApr 23 2011Apr 26 2011Let $K$ be a number field. The \textit{integral trace form} is the integral quadratic form given by $\text{tr}_{K/\mathbb{Q}}(x^2)|_{O_{K}}.$ In this article we study the existence of non-conjugated number fields with equivalent integral trace forms. ... More