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A Complete Method of Comparative Statics for Optimization Problems (Unabbreviated Version)Oct 27 2013A new method of deriving comparative statics information using generalized compensated derivatives is presented which yields constraint-free semidefiniteness results for any differentiable, constrained optimization problem. More generally, it applies ... More

Duality for the left and right fractional derivativesSep 18 2014We prove duality between the left and right fractional derivatives, independently on the type of fractional operator. Main result asserts that the right derivative of a function is the dual of the left derivative of the dual function or, equivalently, ... More

Multi-level pinning problems for random walks and self-avoiding lattice pathsOct 10 2014We consider a generalization of the classical pinning problem for integer-valued random walks conditioned to stay non-negative. More specifically, we take pinning potentials of the form $\sum_{j\geq 0}\epsilon_j N_j$, where $N_j$ is the number of visits ... More

On the probability of staying above a wall for the (2+1)-dimensional SOS model at low temperatureJun 04 2014Nov 09 2015We obtain sharp asymptotics for the probability that the (2+1)-dimensional discrete SOS interface at low temperature is positive in a large region. For a square region $\Lambda$, both under the infinite volume measure and under the measure with zero boundary ... More

Random walk on sparse random digraphsAug 26 2015Jan 22 2018A finite ergodic Markov chain exhibits cutoff if its distance to equilibrium remains close to its initial value over a certain number of iterations and then abruptly drops to near 0 on a much shorter time scale. Originally discovered in the context of ... More

Approximate tensorization of entropy at high temperatureMay 03 2014Feb 16 2015We show that for weakly dependent random variables the relative entropy functional satisfies an approximate version of the standard tensorization property which holds in the independent case. As a corollary we obtain a family of dimensionless logarithmic ... More

Calorimeter-only analysis of the Fermi Large Area TelescopeMar 04 2015Above tens of GeV, gamma-ray observations with the Fermi Large Area Telescope (LAT) can be dominated by statistical uncertainties due to the low flux of sources and the limited acceptance. We are developing a new event class which can improve the acceptance: ... More

Radiative Axion InflationFeb 07 2019Planck data robustly exclude the simple $\lambda\phi^4$ scenario for inflation. This is also the case for models of Axion Inflation in which the inflaton field is the radial part of the Peccei-Quinn complex scalar field. In this letter we show that for ... More

Splitting in the K-theory localization sequence of number fieldsFeb 15 2010Feb 25 2010Let p be a rational prime and let F be a number field. Then, for each i>0, there is a short exact localization sequence for K_{2i}(F). If p is odd or F is nonexceptional, we find necessary and sufficient conditions for this exact sequence to split: these ... More

The Brauer-Kuroda formula for higher S-class numbers in dihedral extensions of number fieldsApr 17 2010Apr 20 2010Let p be an odd prime and let L/k be a Galois extension of number fields whose Galois group is isomorphic to the dihedral group of order 2p. Let S be a finite set of primes of L which is stable under the action of Gal(L/k). The Lichtenbaum conjecture ... More

Uniform Poincare inequalities for unbounded conservative spin systems: The non-interacting caseFeb 04 2002Mar 17 2003We prove a uniform Poincare' inequality for non-interacting unbounded spin systems with a conservation law, when the single-site potential is a bounded perturbation of a convex function. The result is then applied to Ginzburg-Landau processes to show ... More

On the spectral gap of the Kac walk and other binary collision processesJul 22 2008We give a new and elementary computation of the spectral gap of the Kac walk on the N-sphere. The result is obtained as a by-product of a more general observation which allows to reduce the analysis of the spectral gap of an N-component system to that ... More

On the spectral radius of a random matrix: an upper bound without fourth momentJul 19 2016May 30 2018Consider a square matrix with independent and identically distributed entries of zero mean and unit variance. It is well known that if the entries have a finite fourth moment, then, in high dimension, with high probability, the spectral radius is close ... More

Three-dimensional Fermi surface of 2H-NbSe$_2$ - Implications for the mechanism of charge density wavesJul 23 2018We investigate the three-dimensional electronic structure of the seminal charge-density-wave (CDW) material 2H-NbSe$_2$ by soft x-ray angle-resolved photoelectron spectroscopy and density-functional theory. Our results reveal the pronounced 3D character ... More

Neutrinos, Cosmic Rays and the MeV BandMar 13 2019The possible association of the blazar TXS 0506+056 with a high-energy neutrino detected by IceCube holds the tantalizing potential to answer three astrophysical questions: 1. Where do high-energy neutrinos originate? 2. Where are cosmic rays produced ... More

Linear nonadiabatic properties of SX Phoenicis variablesFeb 02 2001We present a detailed linear, nonadiabatic pulsational scenario for oscillating Blue Stragglers (BSs)/SX Phoenicis (SX Phe) in Galactic Globular Clusters (GGCs) and in Local Group (LG) dwarf galaxies. The sequences of models were constructed by adopting ... More

Controlling collapse in Bose-Einstein condensates by temporal modulation of the scattering lengthSep 09 2002We consider, by means of the variational approximation (VA) and direct numerical simulations of the Gross-Pitaevskii (GP) equation, the dynamics of 2D and 3D condensates with a scattering length containing constant and harmonically varying parts, which ... More

Search for Gamma-Ray Lines towards Galaxy Clusters with the Fermi-LATOct 30 2015Feb 04 2016We report on a search for monochromatic $\gamma$-ray features in the spectra of galaxy clusters observed by the \emph{Fermi} Large Area Telescope. Galaxy clusters are the largest structures in the Universe that are bound by dark matter (DM), making them ... More

Diffusivity in one-dimensional generalized Mott variable-range hopping modelsJan 09 2007Aug 31 2009We consider random walks in a random environment which are generalized versions of well-known effective models for Mott variable-range hopping. We study the homogenized diffusion constant of the random walk in the one-dimensional case. We prove various ... More

A Note on Wetting Transition for Gradient FieldsSep 10 1999We prove existence of a wetting transition for two types of gradient fields: 1) Continuous SOS models in any dimension and 2) Massless Gaussian model in two dimensions. Combined with a recent result showing the absence of such a transition for Gaussian ... More

An explicit candidate for the set of Steinitz classes of tame Galois extensions with fixed Galois group of odd orderNov 08 2011Mar 04 2012Given a finite group G and a number field k, a well-known conjecture asserts that the set R_t(k,G) of Steinitz classes of tame G-Galois extensions of k is a subgroup of the ideal class group of k. In this paper we investigate an explicit candidate for ... More

Isoperimetric inequalities and mixing time for a random walk on a random point processJul 31 2006Oct 31 2007We consider the random walk on a simple point process on $\Bbb{R}^d$, $d\geq2$, whose jump rates decay exponentially in the $\alpha$-power of jump length. The case $\alpha =1$ corresponds to the phonon-induced variable-range hopping in disordered solids ... More

Scaling limit and cube-root fluctuations in SOS surfaces above a wallFeb 27 2013Consider the classical $(2+1)$-dimensional Solid-On-Solid model above a hard wall on an $L\times L$ box of $\bbZ^2$. The model describes a crystal surface by assigning a non-negative integer height $\eta_x$ to each site $x$ in the box and 0 heights to ... More

Global metallicity of globular cluster stars from colour-magnitude diagramsFeb 27 2002We have developed an homogeneous evolutionary scenario for H- and He-burning low-mass stars by computing updated stellar models for a wide metallicity and age range (0.0002$\le Z \le$0.004 and 9$\le t(Gyr) \le$15, respectively) suitable to study globular ... More

Asymmetric diffusion and the energy gap above the 111 ground state of the quantum XXZ modelJun 26 2001We consider the anisotropic three dimensional XXZ Heisenberg ferromagnet in a cylinder with axis along the 111 direction and boundary conditions that induce ground states describing an interface orthogonal to the cylinder axis. Let $L$ be the linear size ... More

Time scales: from Nabla calculus to Delta calculus and vice versa via dualityOct 01 2009Jan 17 2010In this note we show how one can obtain results from the nabla calculus from results on the delta calculus and vice versa via a duality argument. We provide applications of the main results to the calculus of variations on time scales.

Finite volume approximation of the effective diffusion matrix: The case of independent bond disorderOct 19 2001Consider uniformly elliptic random walk on $\bbZ^d$ with independent jump rates across nearest neighbour bonds of the lattice. We show that the infinite volume effective diffusion matrix can be almost surely recovered as the limit of finite volume periodized ... More

Towards Learning free Naive Bayes Nearest Neighbor-based Domain AdaptationMar 26 2015As of today, object categorization algorithms are not able to achieve the level of robustness and generality necessary to work reliably in the real world. Even the most powerful convolutional neural network we can train fails to perform satisfactorily ... More

Learning Deep Visual Object Models From Noisy Web Data: How to Make it WorkFeb 28 2017Deep networks thrive when trained on large scale data collections. This has given ImageNet a central role in the development of deep architectures for visual object classification. However, ImageNet was created during a specific period in time, and as ... More

Phase ordering after a deep quench: the stochastic Ising and hard core gas models on a treeDec 22 2004Consider a low temperature stochastic Ising model in the phase coexistence regime with Markov semigroup $P_t$. A fundamental and still largely open problem is the understanding of the long time behavior of $\d_\h P_t$ when the initial configuration $\h$ ... More

Entropy dissipation estimates in a Zero-Range dynamicsMay 24 2004Sep 26 2006We study the exponential decay of relative entropy functionals for zero-range processes on the complete graph. For the standard model with rates increasing at infinity we prove entropy dissipation estimates, uniformly over the number of particles and ... More

On the splitting of the exact sequence relating the wild and tame kernelsMar 10 2013Let k be a number field. For an odd prime p and an integer i>1, the i-th \'etale wild kernel is contained in the second cohomology group of o'_k with coefficients in Zp(i), where o'_k is the ring of p-integers of k. Using Iwasawa theory, we give conditions ... More

Gauss sums, Jacobi sums and cyclotomic units related to torsion Galois modulesFeb 16 2014Let $G$ be a finite group and let $N/E$ be a tamely ramified $G$-Galois extension of number fields. We show how Stickelberger's factorization of Gauss sums can be used to determine the stable isomorphism class of various arithmetic $\mathbb{Z}[G]$-modules ... More

Entropy production in nonlinear recombination modelsSep 22 2016We study the convergence to equilibrium of a class of nonlinear recombination models. In analogy with Boltzmann's H theorem from kinetic theory, and in contrast with previous analysis of these models, convergence is measured in terms of relative entropy. ... More

A large deviation principle for Wigner matrices without Gaussian tailsJul 24 2012Oct 28 2014We consider $n\times n$ Hermitian matrices with i.i.d. entries $X_{ij}$ whose tail probabilities $\mathbb {P}(|X_{ij}|\geq t)$ behave like $e^{-at^{\alpha}}$ for some $a>0$ and $\alpha \in(0,2)$. We establish a large deviation principle for the empirical ... More

Leveraging over intact priors for boosting control and dexterity of prosthetic hands by amputeesAug 26 2016Non-invasive myoelectric prostheses require a long training time to obtain satisfactory control dexterity. These training times could possibly be reduced by leveraging over training efforts by previous subjects. So-called domain adaptation algorithms ... More

On fake Z_p extensions of number fieldsJul 07 2008May 10 2009After providing a general result for dihedral extensions, we study the growth of the $p$-part of the class group of the non-normal subfields of the anticyclotomic extension of an imaginary quadratic field, providing a formula of Iwasawa type. Furthermore, ... More

Relaxation time of anisotropic simple exclusion processes and quantum Heisenberg modelsFeb 04 2002Motivated by an exact mapping between anisotropic half integer spin quantum Heisenberg models and asymmetric diffusions on the lattice, we consider an anisotropic simple exclusion process with $N$ particles in a rectangle of $\bbZ^2$. Every particle at ... More

Large deviations of empirical neighborhood distribution in sparse random graphsAug 27 2013Apr 07 2016Consider the Erd\H{o}s-Renyi random graph on n vertices where each edge is present independently with probability c/n, with c>0 fixed. For large n, a typical random graph locally behaves like a Galton-Watson tree with Poisson offspring distribution with ... More

Convergence to equilibrium for a directed (1+d)-dimensional polymerApr 09 2015We consider a flip dynamics for directed (1+d)-dimensional lattice paths with length L. The model can be interpreted as a higher dimensional version of the simple exclusion process, the latter corresponding to the case d=1. We prove that the mixing time ... More

Engineering the Floquet spectrum of superconducting multiterminal quantum dotsMar 12 2019Here we present a theoretical investigation of the Floquet spectrum in multiterminal quantum dot Josephson junctions biased with commensurate voltages. We first draw an analogy between the electronic band theory and superconductivity which enlightens ... More

Search for Gamma-ray Emission from Dark Matter Annihilation in the Small Magellanic Cloud with the Fermi Large Area TelescopeMar 03 2016Mar 29 2016The Small Magellanic Cloud (SMC) is the second-largest satellite galaxy of the Milky Way and is only 60 kpc away. As a nearby, massive, and dense object with relatively low astrophysical backgrounds, it is a natural target for dark matter indirect detection ... More

Screening magnetic fields by a superconducting disk: a simple modelAug 09 2013We introduce a simple approach to evaluate the magnetic field distribution around superconducting samples, based on the London equations; the elementary variable is the vector potential. This procedure has no adjustable parameters, only the sample geometry ... More

Dynamics of point Josephson junctions in a microstrip lineJan 27 2005We model the dynamics of point Josephson junctions in a 1D microstrip line using a wave equation with delta distributed sine nonlinearities. The model is suitable for both low T$_c$ and high T$_c$ systems (0 and $\pi$ junctions). For a single junction ... More

Statics of point Josephson junctions in a micro strip lineJul 11 2006We model the static behavior of point Josephson junctions in a micro strip line using a 1D linear differential equation with delta distributed sine non-linearities. We analyze the maximum current $\gamma_{max}$ crossing the micro strip for a given magnetic ... More

Influence of the passive region on Zero Field Steps for window Josephson junctionsMar 31 2002We present a numerical and analytic study of the influence of the passive region on fluxon dynamics in a window junction. We examine the effect of the extension of the passive region and its electromagnetic characteristics, its surface inductance and ... More

Reaction-diffusion front crossing a local defectJun 14 2011The interaction of a Zeldovich reaction-diffusion front with a localized defect is studied numerically and analytically. For the analysis, we start from conservation laws and develop simple collective variable ordinary differential equations for the front ... More

Discrete sine-Gordon dynamics on networksJun 08 2015In this study we consider the sine-Gordon equation formulated on domains which are not locally homeomorphic to any subset of the Euclidean space. More precisely, we formulate the discrete dynamics on trees and graphs. Each edge is assumed to be a 1D uniform ... More

Highly Degenerate Harmonic Mean Curvature FlowApr 24 2008We study the evolution of a weakly convex surface $\Sigma_0$ in $\R^3$ with flat sides by the Harmonic Mean Curvature flow. We establish the short time existence as well as the optimal regularity of the surface and we show that the boundaries of the flat ... More

Regularity for non-local almost minimal boundaries and applicationsMar 12 2010Jun 09 2011We introduce a notion of non-local almost minimal boundaries similar to that introduced by Almgren in geometric measure theory. Extending methods developed recently for non-local minimal surfaces we prove that flat non-local almost minimal boundaries ... More

Nonlinear waves in networks: a simple approach using the sine--Gordon equationFeb 26 2014To study the propagation of nonlinear waves across Y-- and T--type junctions, we consider the 2D sine--Gordon equation as a model and study the dynamics of kinks and breathers in such geometries. The comparison of the energies reveals that the angle of ... More

Domain Generalization with Domain-Specific Aggregation ModulesSep 28 2018Visual recognition systems are meant to work in the real world. For this to happen, they must work robustly in any visual domain, and not only on the data used during training. Within this context, a very realistic scenario deals with domain generalization, ... More

Looking Under a Better Lamppost: MeV-scale Dark Matter CandidatesMar 14 2019The era of precision cosmology has revealed that about 85% of the matter in the universe is dark matter. Two well-motivated candidates are weakly interacting massive particles (WIMPs) and weakly interacting sub-eV particles (WISPs) (e.g. axions). Both ... More

Synchronization in fiber lasers arraysApr 25 2013We consider an array of fiber lasers coupled through the nearest neighbors. The model is a generalized nonlinear Schroedinger equation where the usual Laplacian is replaced by the graph Laplacian. For a graph with no symmetries, we show that there is ... More

Global regularity of solutions to systems of reaction-diffusion with Sub-Quadratic Growth in any dimensionJan 28 2009This paper is devoted to the study of the regularity of solutions to some systems of reaction--diffusion equations, with reaction terms having a subquadratic growth. We show the global boundedness and regularity of solutions, without smallness assumptions, ... More

Designing arrays of Josephson junctions for specific static responsesMar 12 2007We consider the inverse problem of designing an array of superconducting Josephson junctions that has a given maximum static current pattern as function of the applied magnetic field. Such devices are used for magnetometry and as Terahertz oscillators. ... More

HB Morphology and Age Indicators for Metal-Poor Stellar Systems with Age in the Range of 1 to 20 GyrJul 20 1994Isochrone computations and horizontal branch (HB) models for Y(MS)=0.23 and two values of Z (0.0001, 0.0004)are used to derive constraints on the age indicators and HB morphology of metal-poor clusters with age t (in Gyrs) in the range of 1< t < 20.It ... More

A simple theory for the Raman spikeSep 11 2003The classical stimulated Raman scattering system describing resonant interaction between two electromagnetic waves and a fast relaxing medium wave is studied by introducting a systematic perturbation approach in powers of the relaxation time. We separate ... More

Dynamics of point Josephson junctions in a microstrip lineApr 03 2010We analyze a new long wave model describing the electrodynamics of an array of point Josephson junctions in a superconducting cavity. It consists in a wave equation with Dirac delta function sine nonlinearities. We introduce an adapted spectral problem ... More

Unidirectional Propagation of an Ultra-Short Electromagnetic Pulse in a Resonant Medium with High Frequency Stark ShiftJul 18 2001We consider in the unidirectional approximation the propagation of an ultra short electromagnetic pulse in a resonant medium consisting of molecules characterized by a transition operator with both diagonal and non-diagonal matrix elements. We find the ... More

On the distance of the Magellanic Clouds using Cepheid NIR and optical-NIR Period Wesenheit RelationsDec 18 2012Jan 30 2013We present the largest near-infrared (NIR) data sets, $JHKs$, ever collected for classical Cepheids in the Magellanic Clouds (MCs). We selected fundamental (FU) and first overtone (FO) pulsators, and found 4150 (2571 FU, 1579 FO) Cepheids for Small Magellanic ... More

B, V, I photometry of the complete sample of 23 Cepheids in the field of NGC 1866Sep 28 2005We present the result of BVI photometry, obtained by using FORS@VLT, of the Cepheids present in the field of the Large Magellanic Cloud cluster NGC 1866. We found the 22 known variables plus an additional new Cepheid located about 10' from the cluster ... More

New Baade-Wesselink distances and radii for four metal-rich Galactic CepheidsMar 19 2010We provided accurate estimates of distances, radii and iron abundances for four metal-rich Cepheids, namely V340 Ara, UZ Sct, AV Sgr and VY Sgr. The main aim of this investigation is to constrain their pulsation properties and their location across the ... More

On the relative distance of Magellanic Clouds using Cepheid NlR and Optical-NIR PW relationsApr 07 2013We present new estimates of the relative distance of the Magellanic Clouds (MCs) by using NIR and Optical-NIR Cepheid Period Wesenheit (PW) relations. The relative distances are independent of uncertainties affecting the zero-point of the PW relations, ... More

Star luminosity function as an age indicator for the Dwarf spheroidal Leo IJul 23 1995Star luminosity function, already recognized as an age indicator for old galactic globular clusters, can be used to contrains the age of younger stellar systems like the nearby dwarfs spheroidal Leo I. We compare the observed luminosity function of Leo ... More

Coupling conditions for the nonlinear shallow water equations in forksSep 30 2015Oct 11 2016We study numerically and analytically how nonlinear shallow water waves propagate in a fork. Using a homothetic reduction procedure, conservation laws and numerical analysis in a 2D domain, we obtain simple angle dependent coupling conditions for the ... More

Nonlinear Analysis of Experimental Noisy Time Series in Fluidized Bed SystemsAug 02 1994The paper describes the application of some numerical techniques to analyze and to characterize the observed dynamical behaviour of fluidized bed systems. The preliminary results showed clearly that the dynamics of the considered process can be nonrecurrent ... More

Spectrum of non-Hermitian heavy tailed random matricesJun 09 2010Oct 14 2011Let (X_{jk})_{j,k>=1} be i.i.d. complex random variables such that |X_{jk}| is in the domain of attraction of an alpha-stable law, with 0< alpha <2. Our main result is a heavy tailed counterpart of Girko's circular law. Namely, under some additional smoothness ... More

Random walk on sparse random digraphsAug 26 2015Sep 28 2015A finite ergodic Markov chain exhibits cutoff if its distance to equilibrium remains close to its initial value over a certain number of iterations and then abruptly drops to near 0 on a much shorter time scale. Originally discovered in the context of ... More

Nonlinear energy transmission in the gapMar 09 2001Numerical simulations of the scattering of a linear plane wave incoming onto a nonlinear medium (sine-Gordon) reveals that: i) nonlinearity allows energy transmission in the forbidden band, ii) this nonlinear transmission occurs beyond an energy threshold ... More

Entropic repulsion in $|\nabla φ|^p$ surfaces: a large deviation bound for all $p\geq 1$Jan 12 2017We consider the $(2+1)$-dimensional generalized solid-on-solid (SOS) model, that is the random discrete surface with a gradient potential of the form $|\nabla\phi|^{p}$, where $p\in [1,+\infty]$. We show that at low temperature, for a square region $\Lambda$ ... More

Adaptive Learning to Speed-Up Control of Prosthetic Hands: a Few Things Everybody Should KnowFeb 27 2017A number of studies have proposed to use domain adaptation to reduce the training efforts needed to control an upper-limb prosthesis exploiting pre-trained models from prior subjects. These studies generally reported impressive reductions in the required ... More

Proof of Aldous' spectral gap conjectureJun 06 2009Sep 28 2009Aldous' spectral gap conjecture asserts that on any graph the random walk process and the random transposition (or interchange) process have the same spectral gap. We prove the conjecture using a recursive strategy. The approach is a natural extension ... More

The Carina dSph galaxy: where is the edge?Sep 02 2005Recent cosmological N-body simulations suggest that current empirical estimates of tidal radii in dSphs might be underestimated by at least one order of magnitude. To constrain the plausibility of this theoretical framework, we undertook a multiband (U,B,V,I) ... More

On the evolution of convex hypersurfaces by the $Q_k$ flowApr 03 2009We prove the existence and uniqueness of a $C^{1,1}$ solution of the $Q_k$ flow in the viscosity sense for compact convex hypersurfaces $\Sigma_t$ embedded in $R^{n+1}$ ($n \geq 2$) . In particular, for compact convex hypersurfaces with flat sides we ... More

Convergence to equilibrium of biased plane partitionsMar 29 2009Apr 12 2010We study a single-flip dynamics for the monotone surface in (2+1) dimensions obtained from a boxed plane partition. The surface is analyzed as a system of non-intersecting simple paths. When the flips have a non-zero bias we prove that there is a positive ... More

Propagation of exremely short pulses in non-resonant media: the total Maxwell-Duffing modelSep 04 2003Propagation of extremely short pulses of electromagnetic field (electromagnetic spikes) is considered in the framework of the total Maxwell-Duffing model where anharmonic oscillators with cubic nonlinearities (Duffing model) represent the material medium ... More

Theoretical Models for Classical Cepheids: IV. Mean Magnitudes and Colors and the Evaluation of Distance, Reddening and MetallicityJun 03 1999We discuss the metallicity effect on the theoretical visual and near-infrared PL and PLC relations of classical Cepheids, as based on nonlinear, nonlocal and time--dependent convective pulsating models at varying chemical composition. In view of the two ... More

Recurrence and transience for long-range reversible random walks on a random point processNov 27 2008We consider reversible random walks in random environment obtained from symmetric long--range jump rates on a random point process. We prove almost sure transience and recurrence results under suitable assumptions on the point process and the jump rate ... More

Recognizing Objects In-the-wild: Where Do We Stand?Sep 18 2017May 22 2018The ability to recognize objects is an essential skill for a robotic system acting in human-populated environments. Despite decades of effort from the robotic and vision research communities, robots are still missing good visual perceptual systems, preventing ... More

A deep representation for depth images from synthetic dataSep 30 2016Convolutional Neural Networks (CNNs) trained on large scale RGB databases have become the secret sauce in the majority of recent approaches for object categorization from RGB-D data. Thanks to colorization techniques, these methods exploit the filters ... More

Class number formula for dihedral extensionsMar 11 2018We give an algebraic proof of a class number formula for dihedral extensions of number fields of degree $2q$, where $q$ is any odd integer. Our formula expresses the ratio of class numbers as a ratio of orders of cohomology groups of units and recovers ... More

Radial sine-Gordon kinks as sources of fast breathersMar 18 2013We consider radial sine-Gordon kinks in two, three and higher dimensions. A full two dimensional simulation showing that azimuthal perturbations remain small allows to reduce the problem to the one dimensional radial sine-Gordon equation. We solve this ... More

RR Lyrae stars in Galactic globular clusters. VI. The Period-Amplitude relationSep 20 2007We compare theory and observations for fundamental RR Lyrae in the solar neighborhood and in both Oosterhoff type I (OoI) and type II (OoII) Galactic globular clusters (GGCs). The distribution of cluster RR_ab in the PA_V plane depends not only on the ... More

The Cepheid Period-Luminosity relation and the maser distance to NGC 4258Oct 24 2001In a recent paper describing HST observations of Cepheids in the spiral galaxy NGC 4258, Newman et al. (2001) report that the revised calibrations and methods for the Key Project on the Extragalactic Distance Scale yield that the true distance modulus ... More

On the second overtone stability among SMC CepheidsMar 07 2001We present a new set of Cepheid, full amplitude, nonlinear, convective models which are pulsationally unstable in the second overtone (SO). Hydrodynamical models were constructed by adopting a chemical composition typical for Cepheids in the Small Magellanic ... More

The Topology of RR Lyrae Instability Strip and the Oosterhoff DichotomyJul 11 1995Convective pulsating models with Y=0.24, stellar mass M=0.65Mo, 0.75Mo, under selected assumptions about luminosities and effective temperatures, are used together with stellar atmosphere computations to get the predicted dependence of RR Lyrae instability ... More

RR Lyrae variables in Galactic globular clusters - I: The observational scenarioAug 25 2003In this paper we revisit observational data concerning RR Lyrae stars in Galactic globular clusters, presenting frequency histograms of fundamentalized periods for the 32 clusters having more than 12 pulsators with well recognized period and pulsation ... More

Convex Entropy Decay via the Bochner-Bakry-Emery approachDec 16 2007We develop a method, based on a Bochner-type identity, to obtain estimates on the exponential rate of decay of the relative entropy from equilibrium of Markov processes in discrete settings. When this method applies the relative entropy decays in a convex ... More

Cutoff at the "entropic time" for sparse Markov chainsNov 03 2016We study convergence to equilibrium for a large class of Markov chains in random environment. The chains are sparse in the sense that in every row of the transition matrix $P$ the mass is essentially concentrated on few entries. Moreover, the random environment ... More

Spectrum of large random reversible Markov chains: Heavy-tailed weights on the complete graphMar 20 2009Nov 16 2012We consider the random reversible Markov kernel K obtained by assigning i.i.d. nonnegative weights to the edges of the complete graph over n vertices and normalizing by the corresponding row sum. The weights are assumed to be in the domain of attraction ... More

Mixing times of monotone surfaces and SOS interfaces: a mean curvature approachJan 21 2011We consider stochastic spin-flip dynamics for: (i) monotone discrete surfaces in Z^3 with planar boundary height and (ii) the one-dimensional discrete Solid-on-Solid (SOS) model confined to a box. In both cases we show almost optimal bounds O(L^2polylog(L)) ... More

A recurrent multi-scale approach to RBG-D Object RecognitionJul 31 2018Sep 05 2018Technological development aims to produce generations of increasingly efficient robots able to perform complex tasks. This requires considerable efforts, from the scientific community, to find new algorithms that solve computer vision problems, such as ... More

Multimodal Deep Domain AdaptationJul 31 2018Typically a classifier trained on a given dataset (source domain) does not performs well if it is tested on data acquired in a different setting (target domain). This is the problem that domain adaptation (DA) tries to overcome and, while it is a well ... More

Online Open World RecognitionApr 08 2016As we enter into the big data age and an avalanche of images have become readily available, recognition systems face the need to move from close, lab settings where the number of classes and training data are fixed, to dynamic scenarios where the number ... More

A Testbed for Cross-Dataset AnalysisFeb 24 2014Since its beginning visual recognition research has tried to capture the huge variability of the visual world in several image collections. The number of available datasets is still progressively growing together with the amount of samples per object ... More

Solutions of the 4-species quadratic reaction-diffusion system are bounded and $C^\infty$, in any space dimensionSep 17 2017We establish the boundedness of solutions of reaction-diffusion systems with quadratic (in fact slightly super-quadratic) reaction terms that satisfy a natural entropy dissipation property, in any space dimension N>2. This bound imply the smoothness of ... More

Relaxation time of $L$-reversal chains and other chromosome shufflesDec 22 2004Oct 11 2006We prove tight bounds on the relaxation time of the so-called $L$-reversal chain, which was introduced by R. Durrett as a stochastic model for the evolution of chromosome chains. The process is described as follows. We have $n$ distinct letters on the ... More

Cosmic Rays and Interstellar Medium with Gamma-Ray Observations at MeV EnergiesMar 13 2019Latest precise cosmic-ray (CR) measurements and present gamma-ray observations have started challenging our understanding of CR transport and interaction in the Galaxy. Moreover, because the density of CRs is similar to the density of the magnetic field, ... More

The Carina Project: II. Stellar PopulationsMar 21 2003We present a new (V,B-V) Color-Magnitude Diagram (CMD) of the Carina dwarf spheroidal (dSph) that extends from the tip of the Red Giant Branch (RGB) down to about V=25 mag. Data were collected with the Wide Field Imager (WFI) available at 2.2m ESO/MPI ... More