Results for "Gemma Roig"

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Representation Similarity Analysis for Efficient Task taxonomy & Transfer LearningApr 26 2019Transfer learning is widely used in deep neural network models when there are few labeled examples available. The common approach is to take a pre-trained network in a similar task and finetune the model parameters. This is usually done blindly without ... More
JSIS3D: Joint Semantic-Instance Segmentation of 3D Point Clouds with Multi-Task Pointwise Networks and Multi-Value Conditional Random FieldsApr 01 2019Apr 05 2019Deep learning techniques have become the to-go models for most vision-related tasks on 2D images. However, their power has not been fully realised on several tasks in 3D space, e.g., 3D scene understanding. In this work, we jointly address the problems ... More
Comment on "Ensemble Projection for Semi-supervised Image Classification"Aug 29 2014In a series of papers by Dai and colleagues [1,2], a feature map (or kernel) was introduced for semi- and unsupervised learning. This feature map is build from the output of an ensemble of classifiers trained without using the ground-truth class labels. ... More
Do Deep Neural Networks Suffer from Crowding?Jun 26 2017Crowding is a visual effect suffered by humans, in which an object that can be recognized in isolation can no longer be recognized when other objects, called flankers, are placed close to it. In this work, we study the effect of crowding in artificial ... More
Random Binary Mappings for Kernel Learning and Efficient SVMJul 19 2013Mar 28 2014Support Vector Machines (SVMs) are powerful learners that have led to state-of-the-art results in various computer vision problems. SVMs suffer from various drawbacks in terms of selecting the right kernel, which depends on the image descriptors, as well ... More
Deep Anchored Convolutional Neural NetworksApr 22 2019Convolutional Neural Networks (CNNs) have been proven to be extremely successful at solving computer vision tasks. State-of-the-art methods favor such deep network architectures for its accuracy performance, with the cost of having massive number of parameters ... More
Distributional Semantics and Linguistic TheoryMay 06 2019Distributional semantics provides multi-dimensional, graded, empirically induced word representations that successfully capture many aspects of meaning in natural languages, as shown in a large body of work in computational linguistics; yet, its impact ... More
Hadronization in tau -> K K pi nu_tau decaysSep 29 2008Hadronization in tau -> K K pi nu_tau decays is driven by both vector and axial-vector currents that we study, guided by the following principles: The 1/N_C expansion -worked out at leading order, considering only the contribution of the lightest spin ... More
Foveation-based Mechanisms Alleviate Adversarial ExamplesNov 19 2015Jan 19 2016We show that adversarial examples, i.e., the visually imperceptible perturbations that result in Convolutional Neural Networks (CNNs) fail, can be alleviated with a mechanism based on foveations---applying the CNN in different image regions. To see this, ... More
Stronger Cryptography For Every Device, EverywhereOct 01 2018Generating secure random numbers is a central problem in cryptography that needs a reliable source of enough computing entropy. Without enough entropy available - meaning no good source of secure random numbers - a device is susceptible to cryptographic ... More
Herding Generalizes Diverse M -Best SolutionsNov 14 2016Jan 30 2017We show that the algorithm to extract diverse M -solutions from a Conditional Random Field (called divMbest [1]) takes exactly the form of a Herding procedure [2], i.e. a deterministic dynamical system that produces a sequence of hypotheses that respect ... More
Distributional Semantics and Linguistic TheoryMay 06 2019Jul 04 2019Distributional semantics provides multi-dimensional, graded, empirically induced word representations that successfully capture many aspects of meaning in natural languages, as shown in a large body of work in computational linguistics; yet, its impact ... More
Improving the Hadronization of QCD currents in TAUOLA and PHOKHARAOct 13 2008We present our study of the hadronization structure of both vector and axial-vector currents leading to decays of the tau into two kaons and a pion. The cornerstones of our framework are the large-N_C limit of QCD, the chiral structure exhibited at low ... More
$τ^-\toηπ^-π^0ν_τ$ and $σ(e^+e^-\to ηπ^+π^-)$ at low energiesOct 01 2010We analyze the hadronization structure of $\tau \to \eta \pi^- \pi^0 \nu_\tau$ decays. In the isospin limit only the vector current contributes to this process. We compute the relevant form factor within Resonance Chiral Theory, at leading order in the ... More
Herding Generalizes Diverse M -Best SolutionsNov 14 2016We show that the algorithm to extract diverse M -solutions from a Conditional Random Field (called divMbest [1]) takes exactly the form of a Herding procedure [2], i.e. a deterministic dynamical system that produces a sequence of hypotheses that respect ... More
Towards the (Mexican) discovery of second class currents at Belle-IIAug 08 2016Aug 18 2016Within the SM, the yet unmeasured $\tau^-\to\pi^-\eta^{(\prime)}\nu_\tau$ decays are predicted as a suppressed, isospin-violating effect with branching ratios $\lesssim\mathcal{O}(10^{-5})$. However, they can also proceed through other mechanisms (such ... More
SideRand: A Heuristic and Prototype of a Side-Channel-Based Cryptographically Secure Random Seeder Designed to Be Platform- and Architecture-AgnosticApr 09 2018Generating secure random numbers is vital to the security and privacy infrastructures we rely on today. Having a computer system generate a secure random number is not a trivial problem due to the deterministic nature of computer systems. Servers commonly ... More
Do Smarter People Have Better Passwords?May 08 2018The National Institute of Standards and Technology (NIST) released new guidelines in June of 2017 that recommended new standards for managing and accepting user passwords. Among the new guidelines is a requirement that verifiers should check if a user's ... More
Study of the readout chip and silicon sensor degradation for the CMS pixel upgradeOct 06 2011Hybrid silicon pixel detectors are currently used in the innermost tracking system of the Compact Muon Solenoid (CMS) experiment. Radiation tolerance up to fluences expected for a few years of running of the Large Hadron Collider (LHC) has already been ... More
Measurement of inclusive $b$-quark production at $\sqrt{s}=$7 TeV with the CMS experimentOct 06 2011Measurements performed by the CMS experiment of the cross section for inclusive $b$-quark production in proton-proton collisions at $\sqrt{s}= 7$ TeV are presented. The measurements are based on different methods, such as inclusive jet measurements with ... More
Hadronic and radiative decays of the tau leptonJan 31 2013This PhD thesis studies some hadronic and radiative decays of the tau lepton using a Chiral Lagrangian including resonance fields. After a theoretical introduction, the decays to the $(\pi \pi \pi)^-$, $(KK\pi)^-$ and $\eta^{(\prime)} \pi^- \pi^0$ hadronic ... More
Hadronic matrix elements for TAUOLA: 3 pi and KKpi channelsOct 31 2008We emphasize that the motivation for including our hadronic matrix elements in TAUOLA is not only theoretical. We also show that our expressions describe better the tau to 3pi ALEPH data and are able to fit BABAR data on the isovector component of e^+e^- ... More
Hadronic tau decays into two and three meson modes within Resonance Chiral TheoryJul 31 2009We study two and three meson decays of the tau lepton within the framework of the Resonance Chiral Theory, that is based on the following properties of QCD: its chiral symmetry in the massless case, its large-N_C limit, and the asymptotic behaviour it ... More
Hadronization in three meson channels at tau decays and e+e- cross-sectionJul 29 2009The hadronic form factors in semileptonic decays of the tau and low-energy e+ e- scattering into hadrons can be described accounting for the following fundamental features: the right chiral structure at low energies, the large-N_C limit of QCD and the ... More
A proposal for improving the hadronization of QCD currents in TAUOLAOct 07 2008After overviewing the general features of semileptonic decays of the tau lepton, I will recall the most widely used model for them, namely that of Kuhn-Santamaria (KS), and I will explain the subsequent works that were done along these lines and that ... More
Prospects for discovery of the τ^- \to π^- \ell^+ \ell^- ν_τ decaysJan 17 2014We study the phenomenology of the \tau^- \to \pi^- \nu_\tau \ell^+ \ell^- decays (\ell = e, \mu), predicting the respective branching ratios and di-lepton invariant-mass spectra. In addition to the model-independent (QED) contributions, we investigate ... More
$τ^-\toπ^-η^{(\prime)}ν_τ$ decaysJul 31 2013The vector and scalar form factors relevant to the second-class current $\tau^-\to\pi^-\eta^{(\prime)}\nu_\tau$ processes are evaluated supplementing Chiral Perturbation Theory with the inclusion of resonances as explicit degrees of freedom. While the ... More
Hadronic decays of the tau lepton into K K pion modes within Resonance Chiral TheorySep 24 2007Tau decays into hadrons have a twofold interest: On the one hand, they are a clean environment for studying the hadronization of the left-handed current of QCD, while, on the other side, provide relevant dynamical information of the resonances that mediate ... More
Lepton flavor violation in the Simplest Little Higgs modelOct 05 2016Oct 07 2016Little Higgs Models are a possible elegant solution to the hierarchy problem on the Higgs mass. As they predict naturally small deviations with respect to SM results, they are in agreement with all current experimental data. In this contribution, we review ... More
Resonance Chiral Lagrangians and alternative approaches to hadronic tau decaysOct 30 2014Nov 14 2014Exclusive semi-leptonic decays of the tau lepton offer a clean probe to study the hadronization of QCD currents in its non-perturbative regime and learn about resonance dynamics, which drives strong interactions in these processes. In this theory outlook, ... More
Failure of Breit-Wigner and success of dispersive descriptions of the τ^-\to K^-ην_τdecaysJan 20 2014The \tau^-\to K^-\eta\nu_\tau decays have been studied using Chiral Perturbation Theory extended by including resonances as active fields. We have found that the treatment of final state interactions is crucial to provide a good description of the data. ... More
Up to homotopy algebras with strict unitsNov 26 2018Feb 16 2019We prove the existence of minimal models a la Sullivan for operads with non trivial arity zero. So up to homotopy algebras with strict units are just operad algebras over these minimal models. As an application we give another proof of the formality of ... More
Hadronic currents for $τ^-\toπ^-π^0ν_τ$ and other decays of interest in TAUOLADec 05 2011A new set of hadronic form factors, which has been implemented in TAUOLA, is described.
Gluing and grazing bifurcations in periodically forced 2-dimensional integrate-and-fire modelsOct 10 2016Dec 13 2017In this work we consider a general class of $2$-dimensional hybrid systems. Assuming that the system possesses an attracting equilibrium point, we show that, when periodically driven with a square-wave pulse, the system possesses a periodic orbit which ... More
Gluing and grazing bifurcations in periodically forced 2-dimensional integrate-and-fire modelsOct 10 2016In this work we consider a general 2-dimensional integrate-and-fire model. Assuming that the system possesses and attracting node, we show that, when periodically driven, the systems possesses a periodic orbit which may undergo tangent-grazing or nonsmooth-grazing ... More
DOPING: Generative Data Augmentation for Unsupervised Anomaly Detection with GANAug 23 2018Aug 24 2018Recently, the introduction of the generative adversarial network (GAN) and its variants has enabled the generation of realistic synthetic samples, which has been used for enlarging training sets. Previous work primarily focused on data augmentation for ... More
Sullivan minimal models of operad algebrasDec 12 2016Jan 22 2018We prove the existence of Sullivan minimal models of operad algebras, for a quite wide family of operads in the category of complexes of vector spaces over a field of characteristic zero. Our construction is an adaptation of Sullivan's original step by ... More
The Changing Perception of the Solar SystemJul 16 2015The solar system has changed dramatically since its birth, and so did our understanding of it. A considerable research effort has been invested in the past decade in an attempt to reconstruct the solar system history, including the earliest stages some ... More
The evolution of asteroids in the jumping-Jupiter migration modelSep 21 2015Sep 22 2015In this work, we investigate the evolution of a primordial belt of asteroids, represented by a large number of massless test particles, under the gravitational effect of migrating Jovian planets in the framework of the jumping-Jupiter model. We perform ... More
Decoherent histories for a particle coupled to a von Neumann apparatusMay 23 2014May 25 2015Using the Gell-Mann and Hartle formalism of generalized quantum mechanics of closed systems, we study coarse-grained decoherent histories. The system under consideration is one-dimensional and consists of a particle coupled to a von Neumann apparatus ... More
SEEDS: Superpixels Extracted via Energy-Driven SamplingSep 16 2013Superpixel algorithms aim to over-segment the image by grouping pixels that belong to the same object. Many state-of-the-art superpixel algorithms rely on minimizing objective functions to enforce color ho- mogeneity. The optimization is accomplished ... More
Time Extended Measurement of the Position of a ParticleDec 19 2005The von Neumann interaction between a particle and an apparatus has been considered in the measurement of the position of a particle when the interaction lasts for a finite amount of time. When the measurement has finite duration, both the motion of the ... More
A geometric mechanism of diffusion: Rigorous verification in a priori unstable Hamiltonian systemsJul 16 2010In this paper we consider a representative a priori unstable Hamiltonian system with 2+1/2 degrees of freedom, to which we apply the geometric mechanism for diffusion introduced in the paper Delshams et al., Mem. Amer. Math. Soc. 2006, and generalized ... More
Harbourne, Schenck and Seceleanu's ConjectureJun 02 2016In [HSS], Conjecture 5.5.2, Harbourne, Schenck and Seceleanu conjectured that, for $r=6$ and all $r\ge 8$, the artinian ideal $I=(\ell _1^2,\dots ,l_{r+1}^2)\subset K[x_1, \dots ,x_r]$ generated by the square of $r+1$ general linear forms $\ell _{i}$ ... More
Decoherence in the classical limit of histories of a particle coupled to a von Neumann apparatusJan 17 2016Using the Gell-Mann and Hartle formalism of generalized quantum mechanics of closed systems, we study the classical limit of coarse-grained spacetime histories and their decoherence. The system under consideration is one-dimensional and consists of a ... More
Time-extended measurement of the position of a driven harmonic oscillatorSep 11 2012Feb 11 2013The von Neumann interaction between a particle and an apparatus, both of arbitrary mass, has been considered in the measurement of the position of a simple harmonic oscillator acted on by an external force. When the measurement has finite duration, both ... More
Two new basaltic asteroids in the Outer Main Belt?Apr 02 2007Jan 14 2008The identification of basaltic asteroids in the asteroid Main Belt and the description of their surface mineralogy is necessary to understand the diversity in the collection of basaltic meteorites. Basaltic asteroids can be identified from their visible ... More
$H\to \ell\ell'$ in the Simplest Little Higgs ModelMar 31 2016Aug 22 2016Little Higgs Models are promising constructs to solve the hierarchy problem affecting the Higgs boson mass for generic new physics. However, their preservation of lepton universality forbids them to account for the $H\to\tau\mu$ CMS hint and at the same ... More
Electron Transport in Molecular Junctions with Graphene as Protecting LayerDec 12 2015We present ab-initio transport calculations for molecular junctions that include graphene as a protecting layer between a single molecule and gold electrodes. This vertical setup has recently gained significant interest in experiment for the design of ... More
From Chemistry to Functionality: Trends for the Length Dependence of the Thermopower in Molecular JunctionsDec 12 2015We present a systematic ab-initio study of the length dependence of the thermopower in molecular junctions. The systems under consideration are small saturated and conjugated molecular chains of varying length attached to gold electrodes via a number ... More
Intermittent nulls in PSR B0818-13, and the subpulse-drift alias modeJun 22 2004We show that all long nulls in PSR B0818-13 are trains of rapidly alternating nulls and pulses (each shorter than one pulse period). Sometimes only the nulls coincide with our pulse window, resulting in one of the apparently long nulls seen occasionally. ... More
How Ampere could have derived the Lorentz TransformationsMar 31 2005Lorentz Transformations of Special Relativity are derived from two postulates: the first is the Principle of Relativity, while the postulate of invariance of the velocity of light, used in usual derivations, is replaced by a law of lectro-magneto-statics ... More
Dispersive analysis of $τ^-\toπ^-π^0ν_τ$ Belle dataJan 30 2013We analyse Belle data on the decay $\tau^- \to \pi^- \pi^0 \nu_\tau$ using a dispersive representation of the vector form factor which is consistent with chiral symmetry and preserves analyticity and unitarity exactly. We fit the unknown theoretical parameters ... More
Dispersive representation of the pion vector form factor in $τ\toππν_τ$ decaysJan 29 2013Aug 06 2013We propose a dispersive representation of the charged pion vector form factor that is consistent with chiral symmetry and fulfills the constraints imposed by analyticity and unitarity. Unknown parameters are fitted to the very precise data on $\tau^-\to\pi^-\pi^0\nu_\tau$ ... More
One meson radiative tau decaysSep 14 2010Apr 14 2011We have studied the one meson radiative tau decays: tau- -> nu(tau) pi-(K-) gamma, computing the structure dependent contributions within a Lagrangian approach based on the large-N(C) limit of QCD that ensures the proper low-energy limit dictated by chiral ... More
Resonance Chiral Lagrangian analysis of $τ^- \to η^{(\prime)} π^- π^0 ν_τ$ decaysAug 06 2012Nov 05 2012The hadronization structure of $\tau^- \to \eta \pi^- \pi^0 \nu_\tau$ decays is analyzed using Chiral Perturbation Theory with resonances, considering only the contribution of the lightest meson resonances at leading order in the $1/N_C$ expansion. After ... More
$τ^-\toπ^-γν_τ$ as a source of background on the Lepton Flavour Violating decay $τ^-\toμ^-γ$Oct 14 2010We calculate the decay of $\tau^-\to\pi^-\gamma\nu_\tau$ in the framework of Resonance Chiral Theory ($R\chi T$). By demanding the high energy constraints from QCD on the related form factors, we could predict the various physical observables of $\tau^-\to\pi^-\gamma\nu_\tau$ ... More
Volatility polarization of non-specialized investors' heterogeneous activityFeb 13 2013Financial markets provide an ideal frame for studying decision making in crowded environments. Both the amount and accuracy of the data allows to apply tools and concepts coming from physics that studies collective and emergent phenomena or self-organised ... More
A dispersive analysis of the pion vector form factor and $τ^{-}\to K^{-}K_{S}ν_τ$ decayFeb 06 2019We explore the potential of a combined analysis of the decays $\tau^{-}\to\pi^{-}\pi^{0}\nu_{\tau}$ and $\tau^{-}\to K^{-}K_{S}\nu_{\tau}$ in the determination of the $\rho(1450)$ and $\rho(1700)$ resonance properties in the frame of resonance Chiral ... More
The Algonauts Project: A Platform for Communication between the Sciences of Biological and Artificial IntelligenceMay 14 2019In the last decade, artificial intelligence (AI) models inspired by the brain have made unprecedented progress in performing real-world perceptual tasks like object classification and speech recognition. Recently, researchers of natural intelligence have ... More
Minimal Models for Non-Free Circle ActionsApr 23 2000Let $\Phi \colon \sbat \times M \to M$ be a smooth action of the unit circle $ \sbat$ on a manifold $M$. In this work, we compute the minimal model of $M$ in terms of the orbit space $B$ and the fixed point set $F\subset B$, as a dg-module over the Sullivan's ... More
Godement resolution and operad sheaf homotopy theoryDec 23 2015Jan 09 2016We show how to induce products in sheaf cohomology for a wide variety of coefficients: sheaves of dg commutative and Lie algebras, symmetric Omega-spectra, filtered dg algebras, operads and operad algebras.
Effective-field theory analysis of the $τ^-\to π^-π^0ν_τ$ decaysJun 25 2018Sep 20 2018We perform an effective field theory analysis of the $\tau^- \to \pi^- \pi^0 \nu_\tau$ decays, that includes the most general interactions between Standard Model fields up to dimension six, assuming left-handed neutrinos. We constrain as much as possible ... More
Optimal bispectrum constraints on single-field models of inflationMar 13 2014We use WMAP 9-year bispectrum data to constrain the free parameters of an 'effective field theory' describing fluctuations in single-field inflation. The Lagrangian of the theory contains a finite number of operators associated with unknown mass scales. ... More
Short-Term Meaning Shift: A Distributional ExplorationSep 10 2018Apr 03 2019We present the first exploration of meaning shift over short periods of time in online communities using distributional representations. We create a small annotated dataset and use it to assess the performance of a standard model for meaning shift detection ... More
Projective simulation for artificial intelligenceApr 19 2011Feb 08 2013We propose a model of a learning agent whose interaction with the environment is governed by a simulation-based projection, which allows the agent to project itself into future situations before it takes real action. Projective simulation is based on ... More
The detection of an older population in the Magellanic BridgeSep 02 2012Jan 18 2013The Magellanic system comprises the Large Magellanic Cloud (LMC), the Small Magellanic Cloud (SMC), and the less frequently observed Magellanic Bridge and Magellanic Stream. The Bridge is traced by neutral gas and has an observed stellar component, while ... More
Short-term meaning shift: an exploratory distributional analysisSep 10 2018We investigate diachronic meaning shift that takes place in short periods of time (short-term meaning shift) and in an online community of speakers. We create a small dataset and use it to assess the performance of a standard model for meaning shift detection ... More
Success and Failure of Adaptation-Diffusion Algorithms for Consensus in Multi-Agent NetworksOct 25 2014This paper investigates the problem of distributed stochastic approximation in multi-agent systems. The algorithm under study consists of two steps: a local stochastic approximation step and a diffusion step which drives the network to a consensus. The ... More
Laser-induced reversion of $δ^{'}$ precipitates in an Al-Li alloy: Study on temperature rise in pulsed laser atom probeSep 29 2015The influence of tuning the laser energy during the analyses on the resulting microstructure in a specimen utilizing an ultra-fast laser assisted atom probe was demonstrated by a case study of a binary Al-Li alloy. The decomposition parameters, such as ... More
An Approximation Ratio for BiclusteringDec 17 2007Aug 22 2008The problem of biclustering consists of the simultaneous clustering of rows and columns of a matrix such that each of the submatrices induced by a pair of row and column clusters is as uniform as possible. In this paper we approximate the optimal biclustering ... More
"Show me the cup": Reference with Continuous RepresentationsJun 28 2016One of the most basic functions of language is to refer to objects in a shared scene. Modeling reference with continuous representations is challenging because it requires individuation, i.e., tracking and distinguishing an arbitrary number of referents. ... More
Putting words in context: LSTM language models and lexical ambiguityJun 12 2019In neural network models of language, words are commonly represented using context-invariant representations (word embeddings) which are then put in context in the hidden layers. Since words are often ambiguous, representing the contextually relevant ... More
Scaling properties and universality of first-passage time probabilities in financial marketsJul 06 2011Sep 29 2011Financial markets provide an ideal frame for the study of crossing or first-passage time events of non-Gaussian correlated dynamics mainly because large data sets are available. Tick-by-tick data of six futures markets are herein considered resulting ... More
On the semistability of instanton sheaves over certain projective varietiesMar 10 2006We show that instanton bundles of rank $r\le 2n-1$, defined as the cohomology of certain linear monads, on an $n$-dimensional projective variety with cyclic Picard group are semistable in the sense of Mumford-Takemoto. Furthermore, we show that rank $r\le ... More
Brill-Noether theory for moduli spaces of sheaves on algebraic varietiesJul 21 2008Let $X$ be a smooth projective variety of dimension $n$ and let $H$ be an ample line bundle on $X$. Let $M_{X,H}(r;c_1, ..., c_{s})$ be the moduli space of $H$-stable vector bundles $E$ on $X$ of rank $r$ and Chern classes $c_i(E)=c_i$ for $i=1, ..., ... More
On the normal sheaf of determinantal varietiesMar 28 2014Jun 23 2016Let X be a standard determinantal scheme X \subset \PP^n of codimension c, i.e. a scheme defined by the maximal minors of a t \times (t+c-1) homogeneous polynomial matrix A. In this paper, we study the main features of its normal sheaf \shN_X. We prove ... More
The minimal number of generators of a Togliatti systemJun 19 2015Jan 26 2016We compute the minimal and the maximal bound on the number of generators of a minimal smooth monomial Togliatti system of forms of degree $d$ in $n+1$ variables, for any $d\ge 2$ and $n\geq 2$. We classify the Togliatti systems with number of generators ... More
On the classification of Togliatti systemsOct 07 2017In [MeMR], Mezzetti and Mir\'{o}-Roig proved that the minimal number of generators $\mu (I)$ of a minimal (smooth) monomial Togliatti system $I\subset k[x_{0},\dotsc,x_{n}]$ satisfies $2n+1\le \mu(I)\le \binom{n+d-1}{n-1}$ and they classify all smooth ... More
The weak radiative pion vertex in τ^- ->π^-ν_τl^+ l^- decaysJun 07 2013Jul 31 2013We carry out a detailed study of the branching fractions and lepton pair invariant-mass spectrum of \tau^- ->\pi^- \nu_\tau l^+l^- decays (l=e,\mu). In addition to the model-independent (QED) contributions, we include the structure-dependent (SD) terms, ... More
The orbital distribution of trans-Neptunian objects beyond 50 auJul 27 2016The dynamical structure of the Kuiper belt beyond 50 au is not well understood. Here we report results of a numerical model with long-range, slow and grainy migration of Neptune. The model implies that bodies scattered outward by Neptune to semimajor ... More
On the complexity of the Whitehead minimization problemAug 31 2006Nov 03 2006The Whitehead minimization problem consists in finding a minimum size element in the automorphic orbit of a word, a cyclic word or a finitely generated subgroup in a finite rank free group. We give the first fully polynomial algorithm to solve this problem, ... More
A new approach for sizing trials with composite binary endpoints using anticipated marginal values and accounting for the correlation between componentsJul 03 2018Nov 16 2018Composite binary endpoints are increasingly used as primary endpoints in clinical trials. When designing a trial, it is crucial to determine the appropriate sample size for testing the statistical differences between treatment groups for the primary endpoint. ... More
Modeling the Historical Flux of Planetary ImpactorsDec 27 2016The impact cratering record of the Moon and the terrestrial planets provides important clues about the formation and evolution of the Solar System. Especially intriguing is the epoch 3.8-3.9 Gyr ago (Ga), known as the Late Heavy Bombardment (LHB), when ... More
Ideals generated by submaximal minorsMay 05 2008The goal of this paper is to study irreducible families W(b;a) of codimension 4, arithmetically Gorenstein schemes X of P^n defined by the submaximal minors of a t x t matrix A with entries homogeneous forms of degree a_j-b_i. Under some numerical assumption ... More
n-dimensional Fano varieties of wild representation typeNov 16 2010The aim of this work is to provide the first examples of $n$-dimensional varieties of wild representation type, for arbitrary $n\geq 2$. More precisely, we prove that all Fano blow-ups of $\PP^n$ at a finite number of points are of wild representation ... More
Smooth monomial Togliatti systems of cubicsOct 09 2013May 18 2016The goal of this paper is to solve the conjecture stated in a paper of Mezzetti, Mir\'o-Roig, Ottaviani and classify all smooth minimal monomial Togliatti systems of cubics. More precisely, we classify all minimal monomial artinian ideals generated by ... More
A scaling law beyond Zipf's law and its relation to Heaps' lawMar 04 2013Sep 09 2013The dependence with text length of the statistical properties of word occurrences has long been considered a severe limitation quantitative linguistics. We propose a simple scaling form for the distribution of absolute word frequencies which uncovers ... More
Lightest pseudoscalar exchange contribution to light-by-light scattering piece of the muon g-2Sep 07 2014Sep 09 2014Lightest pseudoscalar (P= pi^0, eta, eta') exchange contribution to the light-by-light (LbL) scattering piece of the muon anomaly, a_mu=(g_mu-2)/2, has been evaluated using a resonance chiral Lagrangian (R\chi L). Best description of pion transition form-factor ... More
Multiple Hypothesis Testing in Pattern DiscoveryJun 29 2009The problem of multiple hypothesis testing arises when there are more than one hypothesis to be tested simultaneously for statistical significance. This is a very common situation in many data mining applications. For instance, assessing simultaneously ... More
The representation type of determinantal varietiesMar 22 2018This work is entirely devoted to construct huge families of indecomposable arithmetically Cohen-Macaulay (resp. Ulrich) sheaves E of arbitrary high rank on a general standard (resp. linear) determinantal scheme X\subset \PP^n of codimension c \ge 1, n-c ... More
Short-Term Meaning Shift: A Distributional ExplorationSep 10 2018Apr 30 2019We present the first exploration of meaning shift over short periods of time in online communities using distributional representations. We create a small annotated dataset and use it to assess the performance of a standard model for meaning shift detection ... More
m-blocks collections and Castelnuovo-Mumford regularity in multiprojective spacesSep 20 2006The main goal of the paper is to generalize Castelnuovo-Mumford regularity for coherent sheaves on projective spaces to coherent sheaves on $n$-dimensional smooth projective varieties $X$ with an $n$-block collection $\cB $ which generates the bounded ... More
Cohomological characterization of vector bundles on multiprojective spacesSep 20 2006We show that Horrock's criterion for the splitting of vector bundles on $\PP^n$ can be extended to vector bundles on multiprojective spaces and to smooth projective varieties with the weak CM property (see Definition 3.11). As a main tool we use the theory ... More
Stability of syzygy bundlesAug 16 2010We show that given integers $N$, $d$ and $n$ such that ${N\ge2}$, ${(N,d,n)\ne(2,2,5)}$, and ${N+1\le n\le\tbinom{d+N}{N}}$, there is a family of $n$ monomials in $K[X_0,\ldots,X_N]$ of degree $d$ such that their syzygy bundle is stable. Case ${N\ge3}$ ... More
Quasi-periodic perturbations of heteroclinic attractor networksSep 16 2018We consider heteroclinic attractor networks motivated by models of competition between neural populations during binocular rivalry. We show that Gamma distributions of dominance times observed experimentally in binocular rivalry and other forms of bistable ... More
$τ^-\to K^-η^{(\prime)}ν_τ$ decays in Chiral Perturbation Theory with ResonancesJul 30 2013Oct 08 2013We have studied the $\tau^-\to K^-\eta^{(\prime)}\nu_\tau$ decays within Chiral Perturbation Theory including resonances as explicit degrees of freedom. We have considered three different form factors according to treatment of final-state interactions. ... More
Togliatti systems and Galois coveringsNov 17 2016We study the homogeneous artinian ideals of the polynomial ring $K[x,y,z]$, generated by the homogenous polynomials of degree $d$ which are invariant under an action of the cyclic group $\mathbb Z/d\mathbb Z$, for any $d\geq 3$. We prove that they are ... More
Consistent high-energy constraints in the anomalous QCD sectorDec 21 2013Apr 17 2014The anomalous <VVP> Green function and related form-factors (pi^0 to gamma^* gamma^* and tau^- to X^- nu_tau vector form-factors, with X^-=(KKpi)^-, phi^- gamma, (phi V)^-) are analyzed in this letter in the large-N_C limit. Within the single (vector ... More
Capture Probability in the 3:1 Mean Motion Resonance with JupiterMar 12 2014We study the capture and crossing probabilities into the 3:1 mean motion resonance with Jupiter for a small asteroid that migrates from the inner to the middle Main Belt under the action of the Yarkovsky effect. We use an algebraic mapping of the averaged ... More