Results for "F. Bianchi"

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The covariogram and Fourier-Laplace transform in $\mathbb{C}^n$Dec 30 2013Apr 29 2016The covariogram $g_{K}$ of a convex body $K$ in $\mathbb{R}^n$ is the function which associates to each $x\in\mathbb{R}^n$ the volume of the intersection of $K$ with $K+x$. Determining $K$ from the knowledge of $g_K$ is known as the Covariogram Problem. ... More
The cross covariogram of a pair of polygons determines both polygons, with a few exceptionsMay 13 2008The cross covariogram g_{K,L} of two convex sets K and L in R^n is the function which associates to each x in R^n the volume of the intersection of K and L+x. Very recently Averkov and Bianchi [AB] have confirmed Matheron's conjecture on the covariogram ... More
Assessing interface coupling in exchange-biased systems via in-field interaction plotsJun 10 2019An in-field interaction plot, $\delta M_{\rm R}$, has been recently introduced, presenting important advantages over the classical remanence plots. Here a general $\delta M_{\rm R}$ is proposed, allowing to assess interactions even in systems with shifted ... More
The covariogram determines three-dimensional convex polytopesMay 12 2008The cross covariogram g_{K,L} of two convex sets K, L in R^n is the function which associates to each x in R^n the volume of the intersection of K with L+x. The problem of determining the sets from their covariogram is relevant in stochastic geometry, ... More
On the homology of the commutator subgroup of the pure braid groupMay 13 2019We study the homology of $[P_n,P_n]$, the commutator subgroup of the pure braid group on $n$ strands, and show that $H_l([P_n,P_n])$ contains a free abelian group of infinite rank for all $1\leq l\leq n-2$. As a consequence we determine the cohomological ... More
Anomalies, RG-flows and Open/Closed String DualityJan 16 2001We discuss the interplay between IR and UV divergences in vacuum configurations with open and unoriented strings. We establish a general one-to-one correspondence between anomalies and R-R tadpoles associated to sectors with non-trivial Witten index. ... More
RG-flows and Open/Closed String DualityJun 22 2000Aug 28 2000We discuss the interpaly between IR and UV divergences in theories with open and unoriented strings in view of the AdS/CFT correspondence. We start by deriving general formulas for the computation of threshold corrections to gauge couplings in generic ... More
Unoriented D-brane Instantons vs Heterotic worldsheet InstantonsDec 12 2007Feb 01 2008We discuss Fermi interactions of four hyperini generated by ``stringy'' instantons in a Type I / Heterotic dual pair on T^4/Z_2.
First order superconducting phase transition in CeCoIn$_5$Mar 14 2002We investigated the magnetic field dependence of the superconducting phase transition in heavy fermion CeCoIn_5 (T_c = 2.3 K) using specific heat, magneto-caloric effect, and thermal expansion measurements. The superconducting transition becomes first ... More
Anomalies & TadpolesFeb 17 2000We show that massless RR tadpoles in vacuum configurations with open and unoriented strings are always related to anomalies. RR tadpoles arising from sectors of the internal SCFT with non-vanishing Witten index are in one-to-one correspondence with conventional ... More
On structure constants with two spinning twist-two operatorsJan 03 2019I consider three-point functions of one protected and two unprotected twist-two operators with spin in N=4 SYM at weak coupling. At one loop I formulate an empiric conjecture for the dependence of the corresponding structure constants on the spins of ... More
The Blaschke-Santalo InequalityDec 01 2013Aug 04 2014The Blaschke-Santal\'o Inequality is the assertion that the volume product of a centrally symmetric convex body in Euclidean space is maximized by (and only by) ellipsoids. In this paper we give a Fourier analytic proof of this fact.
Demazure and local Weyl modules for twisted hyper current algebrasJul 10 2019In this paper, we study local graded Weyl modules and Demazure modules for twisted hypercurrent algebras. We prove that local graded Weyl modules for a twisted hypercurrent algebra are isomorphic to the corresponding level 1 Demazure modules, and moreover, ... More
Identities and isomorphisms of finite-dimensional graded simple algebrasApr 04 2018Jun 07 2018Let $\mathbb F$ be an algebraically closed field, $G$ be an abelian group, and let $A$ and $B$ be arbitrary finite-dimensional $G$-graded simple algebras over $\mathbb F$. We prove that $A$ and $B$ are isomorphic if, and only if, they satisfy the same ... More
Dynamical behavior of a stochastic forward-backward algorithm using random monotone operatorsAug 12 2015Jul 04 2016The purpose of this paper is to study the dynamical behavior of the sequence produced by a forward-backward algorithm involving two random maximal monotone operators and a sequence of decreasing step sizes. Defining a mean monotone operator as an Aumann ... More
Bases for local Weyl modules for the hyper and truncated current $\mathfrak{sl}_2$-algebrasJun 01 2017Jun 14 2017We use the theory of Gr\"obner-Shirshov bases for ideals to construct linear bases for graded local Weyl modules for the (hyper) current and the truncated current algebras associated to the finite-dimensional complex simple Lie algebra $\mathfrak{sl}_2$. ... More
Retrieving convex bodies from restricted covariogram functionsFeb 28 2007The covariogram g_K(x) of a convex body K \subseteq E^d is the function which associates to each x \in E^d the volume of the intersection of K with K+x. Matheron asked whether g_K determines K, up to translations and reflections in a point. Positive answers ... More
Covariograms generated by valuationsJul 05 2013Nov 10 2014Let \phi be a real-valued valuation on the family of compact convex subsets of \mathbb{R}^n and let K be a convex body in \mathbb{R}^n. We introduce the \phi -covariogram g_{K,\phi} of K as the function associating to each x \in \mathbb{R}^n the value ... More
The recent star formation in NGC 6822 from HST imagingMay 14 2006We present HST WFPC2 and STIS imaging of the low metallicity galaxy NGC 6822, performed as part of a study of the young stellar populations in the galaxies of the Local Group. Eleven WFPC2 pointings, with some overlap, cover two regions, extending over ... More
A Poincaré-Bendixson theorem for meromorphic connections on Riemann surfacesJun 26 2014We prove a Poincar\'e-Bendixson theorem describing the asymptotic behavior of geodesics for a meromorphic connection on a compact Riemann surface. We shall also briefly discuss the case of non-compact Riemann surfaces, and study in detail the geodesics ... More
More on La Grande Bouffe: towards higher spin symmetry breaking in AdSApr 19 2005Aug 09 2005We discuss higher spin gauge symmetry breaking in AdS space from a holographic prespective. Indeed, the AdS/CFT correspondence implies that N=4 SYM theory at vanishing coupling constant is dual to a theory in AdS which exhibits higher spin gauge symmetry ... More
Probing Fuzzballs with Particles, Waves and StringsNov 28 2017Feb 24 2018We probe D1D5 micro-state geometries with massless particles, waves and strings. To this end, we study geodetic motion, Klein-Gordon equation and string scattering in the resulting gravitational background. Due to the reduced rotational symmetry, even ... More
Dynamical supersymmetry breaking from unoriented D-brane instantonsApr 14 2009We study the non-perturbative dynamics of an unoriented Z_5-quiver theory of GUT kind with gauge group U(5) and chiral matter. At strong coupling the non-perturbative dynamics is described in terms of set of baryon/meson variables satisfying a quantum ... More
On stringy AdS_5 x S^5 and higher spin holographyMay 07 2003Jun 13 2003We derive the spectrum of Kaluza-Klein descendants of string excitations on AdS_5 x S^5. String states are organized in long multiplets of the AdS supergroup SU(2,2|4,R) with a rich pattern of shortenings at the higher spin enhancement point \lambda=0. ... More
Multiple phase transitions in Ce(Rh,Ir,Co)In5 heavy-fermion superconductorsJul 12 2001Jul 17 2001Magnetic susceptibility, electrical resistivity and heat capacity data for single crystals of Ce(Rh,Ir)1-x(Co,Ir)xIn5 (0 < x < 1) have allowed us to construct a detailed phase diagram for this new family of heavy-fermion superconductors(HFS). CeRh1-xIrxIn5 ... More
Measuring the Universe with galaxy redshift surveysMar 28 2018Galaxy redshift surveys are one of the pillars of the current standard cosmological model and remain a key tool in the experimental effort to understand the origin of cosmic acceleration. To this end, the next generation of surveys aim at achieving sub-percent ... More
Organic molecules in the protoplanetary disk of DG Tau revealed by ALMAFeb 07 2019Planets form in protoplanetary disks and inherit their chemical compositions. It is thus crucial to map the distribution and investigate the formation of simple organics, such as formaldehyde and methanol, in protoplanetary disks. We analyze ALMA observations ... More
Discrete torsion in non-geometric orbifolds and their open-string descendantsOct 28 1999Dec 09 1999We discuss some Z_N^L x Z_N^R orbifold compactifications of the type IIB superstring to D= 4,6 dimensions and their type I descendants. Although the Z_N^L x Z_N^R generators act asymmetrically on the chiral string modes, they result into left-right symmetric ... More
D-brane Instantons on the T^6/Z_3 orientifoldApr 05 2007May 31 2007We give a detailed microscopic derivation of gauge and stringy instanton generated superpotentials for gauge theories living on D3-branes at Z_3-orientifold singularities. Gauge instantons are generated by D(-1)-branes and lead to Affleck, Dine and Seiberg ... More
Novel calibrations of virial black hole mass estimators in active galaxies based on X-ray luminosity and optical/NIR emission linesOct 11 2016Accurately weigh the masses of SMBH in AGN is currently possible for only a small group of local and bright broad-line AGN through reverberation mapping (RM). Statistical demographic studies can be carried out considering the empirical scaling relation ... More
RealPen: Providing Realism in Handwriting Tasks on Touch Surfaces using Auditory-Tactile FeedbackMar 06 2018We present RealPen, an augmented stylus for capacitive tablet screens that recreates the physical sensation of writing on paper with a pencil, ball-point pen or marker pen. The aim is to create a more engaging experience when writing on touch surfaces, ... More
Luminous star-forming galaxies in the SDSS-GALEX databaseFeb 17 2014We use the combined photometric SDSS + GALEX database to look for populations of luminous blue star-forming galaxies. These were initially identified from such a sample at redshifts near 0.4, using SDSS spectra. We make use of the colour index previously ... More
Self-Assembly of Patchy Particles into Polymer Chains: A Parameter-Free Comparison between Wertheim Theory and Monte Carlo SimulationJan 22 2007We numerically study a simple fluid composed of particles having a hard-core repulsion, complemented by two short-ranged attractive (sticky) spots at the particle poles, which provides a simple model for equilibrium polymerization of linear chains. The ... More
One-dimensional spin texture of Bi(441); Quantum Spin Hall properties without a topological insulatorJun 26 2015The high index (441) surface of bismuth has been studied using Scanning Tunnelling Microscopy (STM), Angle Resolved Photoemission Spectroscopy (APRES) and spin-resolved ARPES. The surface is strongly corrugated, exposing a regular array of (110)-like ... More
The Suzaku X-ray spectrum of NGC 3147. Further insights on the best "true" Seyfert 2 galaxy candidateApr 04 2012NGC 3147 is so far the most convincing case of a "true" Seyfert 2 galaxy, i.e. a source genuinely lacking the Broad Line Regions. We obtained a Suzaku observation with the double aim to study in more detail the iron line complex, and to check the Compton-thick ... More
On the spectrum of AdS/CFT beyond supergravityOct 31 2003We test the spectrum of string theory on AdS_5 x S^5 derived in hep-th/0305052 against that of single-trace gauge invariant operators in free N=4 super Yang-Mills theory. Masses of string excitations at critical tension are derived by extrapolating plane-wave ... More
ALE Instantons in String TheorySep 20 1994In this talk we will describe a string solution which contains a self-dual (instantonic) metric and study its properties. Talk given by M.Bianchi at the Seventh Marcel Grossmann Meeting, Stanford July 24-30, 1994.
The Dark Side of FuzzballsNov 06 2018Black holes absorb any particle impinging with an impact parameter below a critical value. We show that 2- and 3-charge fuzzball geometries exhibit a similar trapping behaviour for a selected choice of the impact parameter of incoming massless particles. ... More
XMM-Newton broad-band observations of NGC 7582: Nh variations and fading out of the active nucleusFeb 21 2007We present results from two XMM-Newton observations of the bright classical Seyfert 2 galaxy NGC 7582 taken four years apart (2001 May and 2005 April). We present the analysis of the high-resolution (0.3-1 keV) RGS and low-resolution (0.3-10 keV) EPIC ... More
Outlier classification using Autoencoders: application for fluctuation driven flows in fusion plasmasApr 24 2018Jan 19 2019Understanding the statistics of fluctuation driven flows in the boundary layer of magnetically confined plasmas is desired to accurately model the lifetime of the vacuum vessel components. Mirror Langmuir probes (MLPs) are a novel diagnostic that uniquely ... More
Polar features in the flagellar propulsion of E. coli bacteriaJun 30 2015E. coli bacteria swim following a run and tumble pattern. In the run state all flagella join in a single helical bundle that propels the cell body along approximately straight paths. When one or more flagellar motors reverse direction the bundle unwinds ... More
N=4 Superconformal Characters and Partition FunctionsSep 26 2006Character formulae for positive energy unitary representations of the N=4 superconformal group are obtained through use of reduced Verma modules and Weyl group symmetry. Expansions of these are given which determine the particular representations present ... More
String Theory and ALE InstantonsOct 28 1994We show that the classical equations of motion of the low-energy effective field theory describing the massless modes of the heterotic (or type I) string admit two classes of supersymmetric self--dual backgrounds. The first class, which was already considered ... More
SCUBA observations of NGC 6946Dec 01 1999We present sub-millimetre images of the spiral galaxy NGC 6946 at 450 and 850 um. The observations have been carried out using the scan/map imaging mode of the Sub-millimetre Common User Bolometer Array (SCUBA) at the James Clark Maxwell Telescope (JCMT). ... More
XMM-Newton observations of 4 luminous radio-quiet AGN, and the soft X-ray excess problemJan 30 2008The nature and origin of the soft X-ray excess in radio quiet AGN is still an open issue. The interpretation in terms of thermal disc emission has been challanged by the discovery of the constancy of the effective temperature despite the wide range of ... More
The role of magnetic field for quiescence-outburst models in CVsDec 19 2014In this paper we present the elementary assumptions of our research on the role of the magnetic field in modelling the quiescence-outbursts cycle in Cataclysmic Variables (CVs). The behaviour of the magnetic field is crucial not only to integrate the ... More
HERschel Observations of Edge-on Spirals (HEROES). I: Far-infrared morphology and dust mass determinationMay 14 2013Context. Edge-on spiral galaxies with prominent dust lanes provide us with an excellent opportunity to study the distribution and properties of the dust within them. The HEROES project was set up to observe a sample of seven large edge-on galaxies across ... More
D-strings in unconventional type I vacuum configurationsNov 02 1998Apr 12 1999We determine the spectrum of D-string bound states in various classes of generalized type I vacuum configurations with sixteen and eight supercharges. The precise matching of the BPS spectra confirms the duality between unconventional type IIB orientifolds ... More
(Unoriented) T-folds with few T'sDec 31 2008Mar 10 2009We use the combined action of Z_2-chiral reflections (T-dualities) and shifts to build N=1,2 supersymmetric four-dimensional string compactifications with few moduli. In particular, we consider Z_2^4 asymmetric orbifolds of Type IIB on the maximal torus ... More
Higher Spin Symmetry and N=4 SYMMay 07 2004Sep 10 2004We assemble the spectrum of single-trace operators in free N=4 SU(N) SYM theory into irreducible representations of the Higher Spin symmetry algebra hs(2,2|4). Higher Spin representations or YT-pletons are associated to Young tableaux (YT) corresponding ... More
Instanton Effects in Supersymmetric Yang-Mills Theories on ALE Gravitational BackgroundsJul 03 1995In this letter we report on the computation of instanton-dominated correlation functions in supersymmetric YM theories on ALE spaces. Following the approach of Kronheimer and Nakajima, we explicitly construct the self-dual connection on ALE spaces necessary ... More
ALE Instantons in String Effective TheorySep 07 1994We show that the classical equations of motion of the low-energy effective field theory describing the massless modes of the heterotic (or type I) string admit two classes of supersymmetric self--dual backgrounds. The first class, which was already considered ... More
Linear growth of the entanglement entropy and the Kolmogorov-Sinai rateSep 01 2017Feb 26 2018The rate of entropy production in a classical dynamical system is characterized by the Kolmogorov-Sinai entropy rate $h_{\mathrm{KS}}$ given by the sum of all positive Lyapunov exponents of the system. We prove a quantum version of this result valid for ... More
Accelerating strangelets via Penrose process in non-BPS fuzzballsApr 01 2019Ultra High Energy Cosmic Rays may include strangelets, a form of Strange Quark Matter, among their components. We briefly review their properties and discuss how they can be accelerated via Penrose process taking place in singular rotating Kerr black ... More
Some advances on the set covering polyhedron of circulant matricesMay 28 2012Working on the set covering polyhedron of consecutive ones circulant matrices, Argiroffo and Bianchi found a class of facet defining inequalities, induced by a particular family of circulant minors. In this work we extend these results to inequalities ... More
Broadband X-ray spectral analysis of the Seyfert 1 galaxy GRS 1734-292Dec 18 2016We discuss the broadband X-ray spectrum of GRS 1734-292 obtained from non-simultaneous XMM-Newton and NuSTAR observations, performed in 2009 and 2014, respectively. GRS1734-292 is a Seyfert 1 galaxy, located near the Galactic plane at $z=0.0214$. The ... More
Majorization under constraints and bounds of the second Zagreb indexMay 10 2011In this paper we present a theoretical analysis in order to establish maximal and minimal vectors with respect to the majorization order of particular subsets of \Re ^n: Afterwards we apply these issues to the calcula- tion of bounds for a topological ... More
Smoothness in the $l_p$ Minkowski problem for $p<1$Jun 20 2017Oct 21 2018We discuss the smoothness and strict convexity of the solution of the $L_p$ Minkowski problem when $p<1$ and the given measure has a positive density function.
Symmetrization in GeometryMar 02 2016Oct 21 2016The concept of an $i$-symmetrization is introduced, which provides a convenient framework for most of the familiar symmetrization processes on convex sets. Various properties of $i$-symmetrizations are introduced and the relations between them investigated. ... More
ATLASrift - a Virtual Reality applicationOct 30 2015We present ATLASrift - a Virtual Reality application that provides an interactive, immersive visit to ATLAS experiment. We envision it being used in two different ways: first as an educational and outreach tool - for schools, universities, museums and ... More
Training Temporal Word Embeddings with a CompassJun 05 2019Temporal word embeddings have been proposed to support the analysis of word meaning shifts during time and to study the evolution of languages. Different approaches have been proposed to generate vector representations of words that embed their meaning ... More
Continuous-time random walk between Lévy-spaced targets in the real lineJun 06 2018Mar 26 2019We consider a continuous-time random walk which is defined as an interpolation of a random walk on a point process on the real line. The distances between neighboring points of the point process are i.i.d. random variables in the normal domain of attraction ... More
Phase retrieval for characteristic functions of convex bodies and reconstruction from covariogramsMar 23 2010Sep 03 2010We propose strongly consistent algorithms for reconstructing the characteristic function 1_K of an unknown convex body K in R^n from possibly noisy measurements of the modulus of its Fourier transform \hat{1_K}. This represents a complete theoretical ... More
Magnetic order in the S=1/2 two-dimensional molecular antiferromagnet, copper pyrazine perchlorate Cu(Pz)_2(ClO_4)_2Dec 13 2006We present an investigation of magnetic ordering in the two-dimensional S=1/2 quantum magnet Cu(Pz)_2(ClO_4)_2 using specific heat and zero field muon-spin relaxation (\mu^+SR). The magnetic contribution to the specific heat is consistent with an exchange ... More
Two-loop cusp anomaly in ABJM at strong couplingJul 17 2014Oct 01 2014We compute the null cusp anomalous dimension of ABJM theory at strong coupling up to two-loop order. This is done by evaluating corrections to the corresponding superstring partition function, weighted by the $AdS_4\times \mathbb{CP}^3$ action in AdS ... More
Investigating the complex X-ray spectrum of a broad-line 2MASS red quasar: XMM-Newton observation of FTM 0830+3759Jan 14 2010We report results from a 50 ks XMM-Newton observation of the dust-reddened broad-line quasar FTM 0830+3759 (z=0.413) selected from the FIRST/2MASS Red Quasar survey. For this AGN, a very short 9 ks Chandra exposure had suggested a feature-rich X-ray spectrum ... More
Flux and spectral variations in the Circinus GalaxySep 27 2002We report on a dramatic flux (50 % increase in the LECS and MECS band) and spectral variation between two BeppoSAX observations of the Circinus Galaxy performed almost three years apart. Through the analysis of all Chandra observations available in the ... More
The Chandra High Resolution Spectra of Mkn 421Feb 26 2001Mkn 421 was observed by Chandra twice, on November 5, 1999 as part of the Chandra calibration program, with the ACIS-HETG configuration, and on May 29, 2000 following our Target Of Opportunity request aimed to catch the source in an ultra-high state, ... More
Modelling the Far-Infrared emission in spyral galaxiesNov 22 1999This thesis presents an original model for the FIR emission in spirals, developed from an existing radiative transfer code (Bianchi, Ferrara & Giovanardi, 1996, ApJ, 465, 127). The model's main features are: a complete treatment of multiple scattering ... More
Dust Extinction and Emission in a Clumpy Galactic Disk. An Application of the Radiative Transfer Code TRADINGJul 18 2008Jul 24 2008AIMS: I present the Monte Carlo radiative transfer code TRADING (Transfer of RAdiation through Dust In Galaxies). The code computes self-consistently the extinction of radiation in a dusty medium (including absorption and scattering) and the dust emission. ... More
Black hole entropy from graviton entanglementNov 02 2012Jan 07 2013We argue that the entropy of a black hole is due to the entanglement of matter fields and gravitons across the horizon. While the entanglement entropy of the vacuum is divergent because of UV correlations, we show that low-energy perturbations of the ... More
Black Hole Entropy, Loop Gravity, and Polymer PhysicsNov 25 2010Loop Gravity provides a microscopic derivation of Black Hole entropy. In this paper, I show that the microstates counted admit a semiclassical description in terms of shapes of a tessellated horizon. The counting of microstates and the computation of ... More
On dominating set polyhedra of circular interval graphsDec 19 2017Feb 20 2018Clique-node and closed neighborhood matrices of circular interval graphs are circular matrices. The stable set polytope and the dominating set polytope on these graphs are therefore closely related to the set packing polytope and the set covering polyhedron ... More
Braid groups, mapping class groups and their homology with twisted coefficientsJan 23 2019Jan 27 2019We consider the Birman-Hilden inclusion $\varphi\colon\mathfrak{Br}_{2g+1}\to\Gamma_{g,1}$ of the braid group into the mapping class group of an orientable surface with boundary, and prove that $\varphi$ is stably trivial in homology with twisted coefficients ... More
Perturbation theory for string sigma modelsApr 06 2016Apr 07 2016In this thesis we investigate quantum aspects of the Green-Schwarz superstring in various AdS backgrounds relevant for the AdS/CFT correspondence, providing several examples of perturbative computations in the corresponding integrable sigma-models. We ... More
The length operator in Loop Quantum GravityJun 28 2008Sep 11 2008The dual picture of quantum geometry provided by a spin network state is discussed. From this perspective, we introduce a new operator in Loop Quantum Gravity - the length operator. We describe its quantum geometrical meaning and derive some of its properties. ... More
The Galaxy Evolution Explorer (GALEX). Its legacy of UV surveys, and science highlightsApr 18 2014The Galaxy Evolution Explorer (GALEX) imaged the sky in the Ultraviolet (UV) for almost a decade, delivering the first sky surveys at these wavelengths. Its database contains far-UV (FUV, $\lambda$$_{eff}$ $\sim$ 1528\AA) and near-UV (NUV, $\lambda$$_{eff}$ ... More
Quadratic Chabauty for (bi)elliptic curves and Kim's conjectureApr 09 2019We explore a number of problems related to the quadratic Chabauty method for determining integral points on hyperbolic curves. We remove the assumption of semistability in the description of the quadratic Chabauty sets $\mathcal{X}(\mathbb{Z}_p)_2$ containing ... More
A temporal semantics for Nilpotent Minimum logicOct 22 2013In [Ban97] a connection among rough sets (in particular, pre-rough algebras) and three-valued {\L}ukasiewicz logic {\L}3 is pointed out. In this paper we present a temporal like semantics for Nilpotent Minimum logic NM ([Fod95, EG01]), in which the logic ... More
Higher Spins and Stringy AdS5xS5Sep 29 2004In this lecture I review recent work on higher spin holography. After a notational flash on the AdS/CFT correspondence, I will discuss HS symmetry enhancement and derive the spectrum of perturbative type IIB superstring excitations on AdS5 in this limit. ... More
Type I Superstrings without D-branesFeb 12 1997Notwithstanding the central role of D-branes in many recently proposed string dualities, several interesting type I vacua have been found without resorting directly to D-brane technology. In this talk, we analyze a three-generation SO(8)xU(12) chiral ... More
Duality Symmetries in String TheoryNov 24 1995Dec 21 1995We review the status of duality symmetries in superstring theories. These discrete symmetries mark the striking differences between theories of pointlike objects and theories of extended objects. They prove to be very helpful in understanding non-perturbative ... More
Parabolic implosion for endomorphisms of $\mathbb{C}^2$Jul 27 2016We give an estimate of the discontinuity of the large Julia set for a perturbation of a class of maps tangent to the identity, by means of a two-dimensional Lavaurs Theorem. We adapt to our situation a strategy due to Bedford, Smillie and Ueda in the ... More
Splitting of the homology of the punctured mapping class groupMar 14 2019Let $\Gamma_{g,1}^m$ be the mapping class group of the orientable surface $\Sigma_{g,1}^m$ of genus $g$ with one parametrised boundary curve and $m$ permutable punctures; when $m=0$ we omit it from the notation. Let $\beta_{m}(\Sigma_{g,1})$ be the braid ... More
Deep Thermal Imaging: Proximate Material Type Recognition in the Wild through Deep Learning of Spatial Surface Temperature PatternsMar 06 2018We introduce Deep Thermal Imaging, a new approach for close-range automatic recognition of materials to enhance the understanding of people and ubiquitous technologies of their proximal environment. Our approach uses a low-cost mobile thermal camera integrated ... More
A search for changing-look AGN in the Grossan catalogJul 13 2005We observed with XMM-Newton 4 objects selected from the Grossan catalog, with the aim to search for new 'changing-look' AGN. The sample includes all the sources which showed in subsequent observations a flux much lower than the one measured with HEAO ... More
Hot and dense water in the inner 25 AU of SVS13-AJun 22 2016In the context of the ASAI (Astrochemical Surveys At IRAM) project, we carried out an unbiased spectral survey in the millimeter window towards the well known low-mass Class I source SVS13-A. The high sensitivity reached (3-12 mK) allowed us to detect ... More
Determination of Gd concentration profile in UO2-Gd2O3 fuel pelletsFeb 28 2014A transversal mapping of the Gd concentration was measured in UO2-Gd2O3 nuclear fuel pellets by electron paramagnetic resonance spectroscopy (EPR). The quantification was made from the comparison with a Gd2O3 reference sample. The nominal concentration ... More
An XMM-Newton view of the `bare' nucleus of Fairall 9Mar 31 2011We present the spectral results from a 130 ks observation, obtained from the X-ray Multi-Mirror Mission-Newton (XMM-Newton) observatory, of the type I Seyfert galaxy Fairall 9. An X-ray hardness-ratio analysis of the light-curves, reveals a `softer-when-brighter' ... More
Signatures of recent star formation in ring S0 galaxiesJan 05 2011We present a study of the stellar populations of ring and/or arm-like structures in a sample of S0 galaxies using GALEX far- and near-ultraviolet imaging and SDSS optical data. Such structures are prominent in the UV and reveal recent star formation. ... More
The bolometric luminosity of type 2 AGN from extinction-corrected [OIII]: no evidence for Eddington-limited sourcesMay 27 2009There have been recent claims that a significant fraction of type 2 AGN accrete close or even above the Eddington limit. In type 2 AGN the bolometric luminosity (L_b) is generally inferred from the [OIII] emission line luminosity (L_OIII). The key issue, ... More
Heavy absorption and soft X-ray emission lines in the XMM-Newton spectrum of the Type 2 radio-loud quasar 3C 234Dec 20 2007We report results on a 40 ks XMM-Newton observation of the Type 2 quasar 3C 234. Optical spectropolarimetric data have demonstrated the presence of a hidden broad-line region in this powerful (M_V <~ -24.2 after reddening and starlight correction) narrow-line ... More
The coronal energy input from magnetic braidingMar 18 2014We estimate the energy input into the solar corona from photospheric footpoint motions, using observations of a plage region by the Hinode Solar Optical Telescope. Assuming a perfectly ideal coronal evolution, two alternative lower bounds for the Poynting ... More
Magneto-optical behaviour of EuIn_2P_2Sep 06 2007We report results of a magneto-optical investigation of the Zintl-phase compound EuIn$_2$P$_2$. The compound orders magnetically at $T_C$=24 K and exhibits concomitant large magnetoresistance effects. For $T\le$50 K and increasing magnetic fields we observe ... More
Mapping the submillimeter spiral wave in NGC 6946Apr 03 2002We have analysed SCUBA 850\mum images of the (near) face-on spiral galaxy NGC 6946, and found a tight correlation between dust thermal emission and molecular gas. The map of visual optical depth relates well to the distribution of neutral gas (HI+H2) ... More
The Local Universe as Seen in Far-Infrared and in Far-Ultraviolet: A Global Point of View on the Local Recent Star FormationSep 27 2006We select far-infrared (FIR-60 microns) and far-ultraviolet (FUV-1530 A) samples of nearby galaxies in order to discuss the biases encountered by monochromatic surveys (FIR or FUV). Very different volumes are sampled by each selection and much care is ... More
Old and young stellar populations in DustPedia galaxies and their role in dust heatingMar 14 2019Apr 16 2019Within the framework of the DustPedia project we investigate the properties of cosmic dust and its interaction with the stellar radiation (originating from different stellar populations) for 814 galaxies in the nearby Universe, all observed by the Herschel ... More
Unabsorbed Seyfert 2 galaxies: the case of "naked" AGNJun 10 2009Hawkins (2004) reported on a class of "naked" AGN characterized by strong amplitude optical brightness variability and the complete absence of broad emission lines in the optical spectrum. The variability suggests that the nucleus is seen directly, however ... More
Worldsheet scattering for the GKP stringAug 28 2015We initiate the perturbative study of the S-matrix for the excitations on top of the GKP vacuum at strong coupling. Using the string sigma model action expanded around the null cusp classical solution, we compute the tree-level S-matrix elements and compare ... More
Keck/Deimos Spectroscopy of a GALEX UV Selecte Sample from the Medium Imaging SurveyJun 23 2007We report results from a pilot program to obtain spectroscopy for objects detected in the Galaxy Evolution Explorer (GALEX) Medium Imaging Survey (MIS). Our study examines the properties of galaxies detected by GALEX fainter than the Sloan Digital Sky ... More