Results for "D. Breton"

total 125354took 0.20s
Functional macroscopic behavior of weighted random ball modelFeb 26 2010We consider a generalization of the weighted random ball model. The model is driven by a random Poisson measure with a product heavy tailed intensity measure. Such a model typically represents the transmission of a network of stations with a fading effect. ... More
(2+1)-dimensional Static Cyclic Symmetric Traversable Wormhole: Quasinormal Modes and CausalityJun 11 2019In this paper we study a static cyclic symmetric traversable wormhole in $(2+1)-$dimensional gravity coupled to nonlinear electrodynamics in anti-de Sitter spacetime. The solution is characterized by three parameters: mass $M$, cosmological constant $\Lambda$ ... More
Exact confidence intervals for the Hurst parameter of a fractional Brownian motionJan 28 2009In this short note, we show how to use concentration inequalities in order to build exact confidence intervals for the Hurst parameter associated with a one-dimensional fractional Brownian motion
Commissioning and operation of the Cherenkov detector for proton Flux Measurement of the UA9 ExperimentApr 12 2019The UA9 Experiment at CERN-SPS investigates channeling processes in bent silicon crystals with the aim to manipulate hadron beams. Monitoring and characterization of channeled beams in the high energy accelerators environment ideally requires in-vacuum ... More
Towards a quantum approach to cell membrane electrodynamicsFeb 17 2009The ultimate active constituents of the living medium, membranes, ions and molecules, are at the level of the nanometer. Their interactions thus require a quantum processing. The characteristic Action A, linked to the "quantum objects" : ions, radicals, ... More
Integration and mining of malaria molecular, functional and pharmacological data: how far are we from a chemogenomic knowledge space?Nov 17 2006The organization and mining of malaria genomic and post-genomic data is highly motivated by the necessity to predict and characterize new biological targets and new drugs. Biological targets are sought in a biological space designed from the genomic data ... More
Born-Infeld black hole in the isolated horizon frameworkJan 31 2003In this work we probe the Born-Infeld (BI) black hole in the isolated horizon framework. It turns out that the BI black hole is consistent with the heuristic model for colored black holes proposed by Ashtekar et al [(2001) Class.Quant.Grav. v. 18, 919-940]. ... More
Energy Extraction from the Einstein-Born-Infeld Black HoleNov 25 2016The energy extraction from a Einstein-Born-Infeld (EBI) black hole is addressed determining the extension of the ergosphere as well as the extractable energy using the irreducible mass concept. These results are compared with the Reissner-Nordstrom (RN) ... More
Smarr's formula for black holes with non-linear electrodynamicsMay 21 2004It is known that for nonlinear electrodynamics the First Law of Black Hole Mechanics holds, however the Smarr's formula for the total mass does not. In this contribution we discuss the point and determine the corresponding expressions for the Bardeen ... More
Born-Infeld generalization of the Reissner-Nordstrom black holeSep 06 2001In this work we study the trajectories of test particles in a geometry that is the nonlinear electromagnetic generalization of the Reissner-Nordstrom solution. The studied spacetime is a Einstein-Born-Infeld solution, nonsingular outside a regular event ... More
About Gaussian filtering problems with general exponential quadratic criteriaFeb 05 2009Filtering problems with general exponential quadratic criteria are investigated for Gauss-Markov processes. In this setting, the Linear Exponential Gaussian and Risk-Sensitive filtering problems are solved and it is shown that they may have different ... More
Stability of nonlinear magnetic black holesFeb 24 2005May 25 2005We study the stability of static spherically symmetric exact solutions of Einstein equations coupled with nonlinear electrodynamics, in the magnetic sector. These solutions satisfy the heuristic model proposed by Ashtekar-Corichi-Sudarsky for hairy black ... More
The long-term evolution of the X-ray pulsar XTE J1814-338: a receding jet contribution to the quiescent optical emission?Sep 23 2013We present a study of the quiescent optical counterpart of the Accreting Millisecond X-ray Pulsar XTE J1814-338, carrying out multiband (BVR) orbital phase-resolved photometry using the ESO VLT/FORS2. The optical light curves are consistent with a sinusoidal ... More
Cascaded Projection: End-to-End Network Compression and AccelerationMar 12 2019We propose a data-driven approach for deep convolutional neural network compression that achieves high accuracy with high throughput and low memory requirements. Current network compression methods either find a low-rank factorization of the features ... More
Black Hole-Wormhole transition in (2+1) Einstein -- anti-de Sitter Gravity Coupled to Nonlinear ElectrodynamicsOct 26 2018Jul 02 2019In this paper we present two results in $(2+1)$ gravity coupled to nonlinear electrodynamics. First it is determined the general form of the electromagnetic field tensor in $(2+1)$ gravity coupled to nonlinear electrodynamics in stationary cyclic spacetimes. ... More
Regularity of the laws of shot noise series and of related processesOct 01 2009We investigate the regularity of shot noise series and of Poisson integrals. We give conditions for the absolute continuity of their law with respect to Lebesgue measure and for their continuity in total variation norm. In particular, the case of truncated ... More
Geodesic Motion in the 5D Magnetized Schwarzschild-Like SolutionsMar 10 1994Geodesics for a 5D magnetized Schwarzschild-like solution are analyzed by reducing the problem to the motion of a test particle in an effective potential. In absence of magnetic field comparison is established with Schwarzschild's geometry. Embedding ... More
Radio Pulsars in Binary SystemsJul 15 2009This thesis focuses on the study of binary radio pulsars, their evolution and some specific use of their properties to investigate fundamental physics such as general relativity and other gravitational theories. The work that we present here is organized ... More
Black Hole-Wormhole transition in (2+1) Einstein -anti- de Sitter Gravity Coupled to Nonlinear ElectrodynamicsOct 26 2018In this paper we present two results in $(2+1)$ gravity coupled to nonlinear electrodynamics. First it is determined the general form of the electromagnetic field tensor in $(2+1)$ gravity coupled to nonlinear electrodynamics in stationary cyclic spacetimes. ... More
DEFRAG: Deep Euclidean Feature Representations through Adaptation on the Grassmann ManifoldJun 20 2018We propose a novel technique for training deep networks with the objective of obtaining feature representations that exist in a Euclidean space and exhibit strong clustering behavior. Our desired features representations have three traits: they can be ... More
Automatic classification of K2 pulsating stars using machine learning techniquesJun 23 2019The second mission of the NASA Kepler satellite, K2, has collected hundreds of thousands of lightcurves for stars close to the ecliptic plane. This new sample could increase the number of known pulsating stars and then improve our understanding of those ... More
Study of timing characteristics of a 3 m long plastic scintillator counter using waveform digitizersOct 18 2016A plastic scintillator bar with dimensions 3 m x 2.5 cm x 11 cm was exposed to a focused muon beam to study its light yield and timing characteristics as a function of position and angle of incidence. The scintillating light was read out at both ends ... More
Probing Cosmology with Dark Matter Halo Sparsity Using X-ray Cluster Mass MeasurementsNov 01 2017Jun 12 2018We present a new cosmological probe for galaxy clusters, the halo sparsity. This characterises halos in terms of the ratio of halo masses measured at two different radii and carries cosmological information encoded in the halo mass profile. Building upon ... More
LOFAR MSSS: The Scaling Relation between AGN Cavity Power and Radio Luminosity at Low Radio FrequenciesJun 01 2017We present a new analysis of the widely used relation between cavity power and radio luminosity in clusters of galaxies with evidence for strong AGN feedback. We study the correlation at low radio frequencies using two new surveys - the First Alternative ... More
Validation of the GATE Monte Carlo simulation platform for modelling a CsI(Tl) scintillation camera dedicated to small animal imagingNov 26 2004Monte Carlo simulations are increasingly used in scintigraphic imaging to model imaging systems and to develop and assess tomographic reconstruction algorithms and correction methods for improved image quantitation. GATE (GEANT 4 Application for Tomographic ... More
Error bounds on the non-normal approximation of Hermite power variations of fractional Brownian motionApr 16 2008Let $q\geq 2$ be a positive integer, $B$ be a fractional Brownian motion with Hurst index $H\in(0,1)$, $Z$ be an Hermite random variable of index $q$, and $H_q$ denote the Hermite polynomial having degree $q$. For any $n\geq 1$, set $V_n=\sum_{k=0}^{n-1} ... More
On the limiting law of the length of the longest common and increasing subsequences in random wordsMay 22 2015Aug 24 2018Let $X=(X_i)_{i\ge 1}$ and $Y=(Y_i)_{i\ge 1}$ be two sequences of independent and identically distributed (iid) random variables taking their values, uniformly, in a common totally ordered finite alphabet. Let LCI$_n$ be the length of the longest common ... More
Nonlinear Electrodynamics and black holesFeb 01 2007It is addressed the issue of black holes with nonlinear electromagnetic field, focussing mainly in the Born-Infeld case. The main features of these systems are described, for instance, geodesics, energy conditions, thermodynamics and isolated horizon ... More
Nonlinear electrodynamics in Bianchi spacetimesDec 11 2002Sep 26 2003We study the effects produced by nonlinear electrodynamics in spacetimes conformal to Bianchi metrics. In the presence of Born-Infeld type fields these models accelerate, expand and isotropize. This effect is compared with the corresponding to a linear ... More
Factorial moments of point processesOct 13 2013We derive joint factorial moment identities for point processes with Papangelou intensities. Our proof simplifies previous approaches to related moment identities and includes the setting of Poisson point processes. Applications are given to random transformations ... More
On the limiting law of the length of the longest common and increasing subsequences in random wordsMay 22 2015Sep 20 2016Let $X=(X_i)_{i\ge 1}$ and $Y=(Y_i)_{i\ge 1}$ be two sequences of independent and identically distributed (iid) random variables taking their values, uniformly, in a common totally ordered finite alphabet. Let LCI$_n$ be the length of the longest common ... More
Quasinormal modes of nonlinear electromagnetic black holes from unstable null geodesicsJul 08 2016The expressions for the quasinormal modes (QNMs) of black holes with nonlinear electrodynamics, calculated in the eikonal approximation, are presented. In the eikonal limit QNMs of black holes are determined by the parameters of the circular null geodesics. ... More
Singularity-free Bianchi spaces with nonlinear electrodynamicsOct 28 2004Feb 24 2005In this paper we present an analysis to determine the existence of singularities in spatially homogeneous anisotropic universes filled with nonlinear electromagnetic radiation. These spaces are conformal to Bianchi spaces admitting a three parameter group ... More
Asymptotics for random Young diagrams when the word length and alphabet size simultaneously grow to infinityDec 18 2008Oct 11 2010Given a random word of size $n$ whose letters are drawn independently from an ordered alphabet of size $m$, the fluctuations of the shape of the random RSK Young tableaux are investigated, when $n$ and $m$ converge together to infinity. If $m$ does not ... More
Integrability and regularity of the flow of stochastic differential equations with jumpsFeb 10 2019We derive sufficient conditions for the differentiability of all orders for the flow of stochastic differential equations with jumps, and prove related $L^p$-integrability results for all orders. Our results extend similar results obtained in [Kun04] ... More
Asymptotic Cramér type decomposition for Wiener and Wigner integralsSep 13 2012We investigate generalizations of the Cram\'er theorem. This theorem asserts that a Gaussian random variable can be decomposed into the sum of independent random variables if and only if they are Gaussian. We prove asymptotic counterparts of such decomposition ... More
Born-Infeld CosmologiesApr 05 2000We present a model for an inhomogeneous and anisotropic early universe filled with a nonlinear electromagnetic field of Born-Infeld (BI) type. The effects of the BI field are compared with the linear case (Maxwell). Since the curvature invaria nts are ... More
Asymptotic singular behaviour of inhomogeneous cosmologies in Einstein-Maxwell-dilaton-axion theoryAug 29 2006We present the study of exact inhomogeneous cosmological solutions to a four-dimensional low energy limit of string theory containing non-minimal interacting electromagnetic, dilaton and axion fields. We analyze Einstein-Rosen solutions of Einstein-Maxwell-dilaton-axion ... More
On finite range stable type concentrationDec 16 2004The purpose of these notes is to further complete our understanding of the stable concentration phenomenon, by obtaining the finite range behavior of $P(F-E[F]\geq x)$, with $F=f(X)$ where $f$ is a Lipschitz function and $X$ is a stable random vector ... More
Rescaled weighted random balls models and stable self-similar random fieldsJul 29 2008Aug 26 2009We consider weighted random balls in $\real^d$ distributed according to a random Poisson measure with heavy-tailed intensity and study the asymptotic behaviour of the total weight of some configurations in $\real^d$. This procedure amounts to be very ... More
The Double Pulsar Eclipses I: Phenomenology and Multi-frequency AnalysisJan 12 2012The double pulsar PSR J0737-3039A/B displays short, 30 s eclipses that arise around conjunction when the radio waves emitted by pulsar A are absorbed as they propagate through the magnetosphere of its companion pulsar B. These eclipses offer a unique ... More
Towards grid-enabled telemedicine in AfricaMay 12 2006Telemedicine services are very relevant tools to train local physicians and to improve diagnosis by exchanging medical data. Telemedicine networks allow these exchanges but the set-up of multipoint dynamic telemedicine requires moving towards GRID technologies. ... More
The double pulsar: evolutionary constraints from the system geometryNov 30 2007Dec 07 2007The double pulsar system PSR J0737-3039A/B is a highly relativistic double neutron star (DNS) binary, with a 2.4-hour orbital period. The low mass of the second-formed NS, as well the low system eccentricity and proper motion, point to a different evolutionary ... More
Relativistic Spin Precession in the Double PulsarJul 16 2008The double pulsar PSR J0737-3039A/B consists of two neutron stars in a highly relativistic orbit that displays a roughly 30-second eclipse when pulsar A passes behind pulsar B. Describing this eclipse of pulsar A as due to absorption occurring in the ... More
Pulsar Wind Nebulae in the SKA eraJan 02 2015Neutron stars lose the bulk of their rotational energy in the form of a pulsar wind: an ultra-relativistic outflow of predominantly electrons and positrons. This pulsar wind significantly impacts the environment and possible binary companion of the neutron ... More
LOFAR MSSS: Discovery of a 2.56 Mpc giant radio galaxy associated with a disturbed galaxy groupFeb 06 2017We report on the discovery in the LOFAR Multifrequency Snapshot Sky Survey (MSSS) of a giant radio galaxy (GRG) with a projected size of $2.56 \pm 0.07$ Mpc projected on the sky. It is associated with the galaxy triplet UGC 9555, within which one is identified ... More
Exponential transform of quadratic functional and multiplicative ergodicity of a Gauss-Markov processDec 19 2013Dec 20 2013The Laplace transform of partial sums of the square of a non-centered Gauss-Markov process, conditioning on its starting point, is explicitly computed. The parameters of multiplicative ergodicity are deduced.
Macroscopic analysis of determinantal random ballsApr 17 2015Jun 01 2017We consider a collection of Euclidean random balls in ${\Bbb R}^d$ generated by a determinantal point process inducing interaction into the balls. We study this model at a macros\-copic level obtained by a zooming-out and three different regimes --Gaussian, ... More
Dimension free and infinite variance tail estimates on Poisson spaceDec 17 2004Concentration inequalities are obtained on Poisson space, for random functionals with finite or infinite variance. In particular, dimension free tail estimates and exponential integrability results are given for the Euclidean norm of vectors of independent ... More
Is there a prescribed parameter's space for the adiabatic geometric phase?Feb 14 2006The Aharonov-Anandan and Berry phases are determined for the cyclic motions of a non-relativistic charged spinless particle evolving in the superposition of the fields produced by a Penning trap and a rotating magnetic field. Discussion about the selection ... More
Grid Added Value to Address MalariaNov 17 2006Through this paper, we call for a distributed, internet-based collaboration to address one of the worst plagues of our present world, malaria. The spirit is a non-proprietary peer-production of information-embedding goods. And we propose to use the grid ... More
Gärtner-Ellis condition for squared asymptotically stationary Gaussian processesFeb 14 2015The G\"artner-Ellis condition for the square of an asymptotically stationary Gaussian process is established. The same limit holds for the conditional distri-bution given any fixed initial point, which entails weak multiplicative ergodicity. The limit ... More
RBFs methods for null control problems of the Stokes system with Dirichlet and Navier slip boundary conditionsNov 01 2018The purpose of this article is to introduce radial basis function, (RBFs), methods for solving null control problems for the Stokes system with few internal scalar controls and Dirichlet or Navier slip boundary conditions. To the best of our knowledge, ... More
Plastic scintillator detector with the readout based on an array of large-area SiPMs for the ND280/T2K upgrade and SHiP experimentsJan 23 2019Plastic scintillator detectors have been extensively used in particle physics experiments for decades. A large-scale detector is typically arranged as an array of staggered long bars which provide a fast trigger signal and/or particle identification via ... More
Colliding Plane Waves in Einstein-Maxwell-Dilaton FieldsNov 22 1995Within the metric structure endowed with two orthogonal space-like Killing vectors a class of solutions of the Einstein-Maxwell-Dilaton field equations is presented. Two explicitly given sub-classes of solutions bear an interpretation as colliding plane ... More
Quasinormal modes and absorption cross sections of Born-Infeld-de Sitter black holesMar 29 2017Mar 31 2017In this paper, we have studied QNM modes and absorption cross sections of Born-Infeld-de Sitter black holes. WKB approximation is employed to compute the QNM modes of massless scalar fields. We have also used null geodesics to compute quasi-normal modes ... More
Confidence intervals for the Hurst parameter of a fractional Brownian motion based on finite sample sizeOct 16 2009May 31 2010In this paper, we show how concentration inequalities for Gaussian quadratic form can be used to propose exact confidence intervals of the Hurst index parametrizing a fractional Brownian motion. Both cases where the scaling parameter of the fractional ... More
Properties of the redback millisecond pulsar binary 3FGL J0212.1+5320Aug 24 2017Linares et al. (2016) obtained quasi-simultaneous g', r' and i-band light curves and an absorption line radial velocity curve of the secondary star in the redback system 3FGL J0212.1+5320. The light curves showed two maxima and minima primarily due to ... More
Convex ordering for random vectors using predictable representationJan 30 2008We prove convex ordering results for random vectors admitting a predictable representation in terms of a Brownian motion and a non-necessarily independent jump component. Our method uses forward-backward stochastic calculus and extends previous results ... More
Innovative in silico approaches to address avian flu using grid technologyDec 23 2008The recent years have seen the emergence of diseases which have spread very quickly all around the world either through human travels like SARS or animal migration like avian flu. Among the biggest challenges raised by infectious emerging diseases, one ... More
Fast Transients at Cosmological Distances with the SKAJan 19 2015Impulsive radio bursts that are detectable across cosmological distances constitute extremely powerful probes of the ionized Inter-Galactic Medium (IGM), intergalactic magnetic fields, and the properties of space-time itself. Their dispersion measures ... More
The double pulsar: evidence for neutron star formation without an iron core-collapse supernovaFeb 12 2013Mar 01 2013The double pulsar system PSR J0737-3039A/B is a double neutron star binary, with a 2.4-hour orbital period, which has allowed measurement of relativistic orbital perturbations to high precision. The low mass of the second-formed neutron star, as well ... More
Measurement of the luminosity at the DAFNE collider upgraded with the crab waist schemeSep 10 2009The test of the crab waist collision scheme, undergoing at the e+e- Frascati DAFNE accelerator complex since February 2008, requires a fast and accurate measurement of the absolute luminosity, as well as a full characterization of the background conditions. ... More
Formation of Double Neutron Star SystemsJun 28 2017Sep 18 2017Double neutron star (DNS) systems represent extreme physical objects and the endpoint of an exotic journey of stellar evolution and binary interactions. Large numbers of DNS systems and their mergers are anticipated to be discovered using the Square-Kilometre-Array ... More
Some properties of evolving wormhole geometries within nonlinear electrodynamicsApr 24 2008In this paper we review some properties for the evolving wormhole solution of Einstein equations coupled with nonlinear electrodynamics. We integrate the geodesic equations in the effective geometry obeyed by photons; we check out the weak field limit ... More
Stress response function of a two-dimensional ordered packing of frictional beadsMay 06 2002Oct 11 2002We study the stress profile of an ordered two-dimensional packing of beads in response to the application of a vertical overload localized at its top surface. Disorder is introduced through the Coulombic friction between the grains which gives some indeterminacy ... More
High-harmonic generation from few layer hexagonal boron nitride: evolution from the monolayer to the bulk responseJul 09 2018Sep 07 2018Two-dimensional materials offer a versatile platform to study high-harmonic generation (HHG), encompassing as limiting cases bulk-like and atomic-like harmonic generation [Tancogne-Dejean and Rubio, Science Advance \textbf{4}, eaao5207 (2018)]. Understanding ... More
Filtering problems with exponential criteria for general Gaussian signalsAug 20 2009Dec 13 2009The explicit solution of the discrete time filtering problems with exponential criteria for a general Gaussian signal is obtained through an approach based on a conditional Cameron-Martin type formula. This key formula is derived for conditional expectations ... More
Evidence for a Massive Neutron Star from a Radial-Velocity Study of the Companion to the Black Widow Pulsar PSR B1957+20Sep 28 2010Dec 14 2010The most massive neutron stars constrain the behavior of ultra-dense matter, with larger masses possible only for increasingly stiff equations of state. Here, we present evidence that the black widow pulsar, PSR B1957+20, has a high mass. We took spectra ... More
The egalitarian sharing rule in provision of public projectsMar 17 2005In this note we consider a society that partitions itself into disjoint jurisdictions, each choosing a location of its public project and a taxation scheme to finance it. The set of public project is multi-dimensional, and their costs could vary from ... More
Constraining Redshifts of Unlocalised Fast Radio BurstsApr 04 2018The population of fast radio bursts (FRBs) will continue to diverge into two groups depending on their method of discovery: those which can be localised, and those which cannot. Events potentially less useful for astronomical and cosmological purposes ... More
A minimal representation of the self-assembly of virus capsidsDec 16 2013Viruses are biological nanosystems with a capsid of protein-made capsomer units that encloses and protects the genetic material responsible for their replication. Here we show how the geometrical constraints of the capsomer-capsomer interaction in icosahedral ... More
A Logic-Based Learning Approach to Explore Diabetes Patient BehaviorsJun 24 2019Type I Diabetes (T1D) is a chronic disease in which the body's ability to synthesize insulin is destroyed. It can be difficult for patients to manage their T1D, as they must control a variety of behavioral factors that affect glycemic control outcomes. ... More
LOFT-e: Localisation Of Fast Transients with e-MERLINApr 04 2018The majority of fast radio bursts (FRBs) are poorly localised, hindering their potential scientific yield as galactic, intergalactic, and cosmological probes. LOFT-e, a digital backend for the U.K.'s e-MERLIN seven-telescope interferometer will provide ... More
Class of colliding plane waves in terms of Jacobi functionsSep 03 1998We present a general class of noncolinear colliding wave solutions of the Einstein-Maxwell equations given in terms of fourth order polynomials, which in turn can be expressed through Jacobi functions depending on generalized advanced and retarded time ... More
Tidal heating in multilayer planets: Application to the TRAPPIST-1 systemOct 26 2018TRAPPIST-1 (Gillon et al. 2017) is an extremely compact planetary system: seven earth-sized planets orbit at distances lower than 0.07 AU around one of the smallest M-dwarf known in the close neighborhood of the Sun (with a mass of less than 0.09 $M_\odot$). ... More
Strain and Magnetic Field Induced Spin-Structure Transitions in Multiferroic BiFeO3Aug 30 2017The magnetic-field-dependent spin ordering of strained BiFeO3 films is determined using nuclear resonant scattering and Raman spectroscopy. The critical field required to destroy the cycloidal modulation of the Fe spins is found to be significantly lower ... More
A LOFAR census of non-recycled pulsars: average profiles, dispersion measures, flux densities, and spectraNov 05 2015May 27 2016We present first results from a LOFAR census of non-recycled pulsars. The census includes almost all such pulsars known (194 sources) at declinations ${\rm Dec}> 8^\circ$ and Galactic latitudes $|{\rm Gb}| > 3^\circ$, regardless of their expected flux ... More
Detection and timing of gamma-ray pulsations from the $707$-Hz pulsar J0952$-$0607May 27 2019The LOFAR radio telescope discovered the $707$-Hz binary millisecond pulsar J0952$-$0607 in a targeted radio pulsation search of an unidentified $\textit{Fermi}$ gamma-ray source. This source shows a weak energy flux of $F_\gamma = 2.6 \times 10^{-12}\,\text{erg}\,\text{cm}^{-2}\,\text{s}^{-1}$ ... More
Orbital and superorbital variability of LS I +61 303 at low radio frequencies with GMRT and LOFARDec 09 2015LS I +61 303 is a gamma-ray binary that exhibits an outburst at GHz frequencies each orbital cycle of $\approx$ 26.5 d and a superorbital modulation with a period of $\approx$ 4.6 yr. We have performed a detailed study of the low-frequency radio emission ... More
The LOFAR Transients PipelineMar 05 2015Current and future astronomical survey facilities provide a remarkably rich opportunity for transient astronomy, combining unprecedented fields of view with high sensitivity and the ability to access previously unexplored wavelength regimes. This is particularly ... More
New methods to constrain the radio transient rate: results from a survey of four fields with LOFARNov 28 2014Mar 21 2016We report on the results of a search for radio transients between 115 and 190\,MHz with the LOw-Frequency ARray (LOFAR). Four fields have been monitored with cadences between 15 minutes and several months. A total of 151 images were obtained, giving a ... More
KOI 1224, a Fourth Bloated Hot White Dwarf Companion Found With KeplerSep 30 2011We present an analysis and interpretation of the Kepler binary system KOI 1224. This is the fourth binary found with Kepler that consists of a thermally bloated, hot white dwarf in a close orbit with a more or less normal star of spectral class A or F. ... More
Homogeneous Cu-Fe super saturated solid solutions prepared by severe plastic deformationJun 17 2010A Cu-Fe nanocomposite containing 50 nm thick iron filaments dispersed in a copper matrix was processed by torsion under high pressure at various strain rates and temperatures. The resulting nanostructures were characterized by transmission electron microscopy, ... More
Kepler K2 observations of the transitional millisecond pulsar PSR J1023+0038Jan 31 2018Mar 16 2018For 80 days in 2017, the Kepler Space Telescope continuously observed the transitional millisecond pulsar system PSR J1023+0038 in its accreting state. We present analyses of the 59 second cadence data, focusing on investigations of the orbital light ... More
Kepler K2 observations of the transitional millisecond pulsar PSR J1023+0038Jan 31 2018For 80 days in 2017, the Kepler Space Telescope continuously observed the transitional millisecond pulsar system PSR J1023$+$0038 in its accreting state. We present analyses of the 59-second cadence data, focusing on investigations of the orbital light ... More
Global Potential Energy Minima of (H$_{2}$O)$_{n}$ Clusters on GraphiteJun 08 2007Likely candidates for the global potential energy minima of (H$_{2}$O)$_{n}$ clusters with $n\leq21$ on the (0001)-surface of graphite are found using basin-hopping global optimization. The potential energy surfaces are constructed using the TIP4P intermolecular ... More
Self-energy limited ion transport in sub-nanometer channelsApr 05 2006Jul 19 2006The current-voltage characteristics of the alpha-Hemolysin protein pore during the passage of single-stranded DNA under varying ionic strength, C, are studied experimentally. We observe strong blockage of the current, weak super-linear growth of the current ... More
Observations of Doppler Boosting in Kepler LightcurvesJan 26 2010Apr 26 2010Among the initial results from Kepler were two striking lightcurves, for KOI 74 and KOI 81, in which the relative depths of the primary and secondary eclipses showed that the more compact, less luminous object was hotter than its stellar host. That result ... More
Multiband Studies of the Optical Periodic Modulation in the X-Ray Binary SAX~J1808.4-3658 during Its Quiescence and 2008 OutburstAug 24 2011Jan 24 2013We report on time-resolved optical imaging of the X-ray binary SAX J1808.4-3658 during its quiescent state and 2008 outburst. The binary, containing an accretion-powered millisecond pulsar, has a large sinusoidal-like modulation in its quiescent optical ... More
A LOFAR census of millisecond pulsarsAug 12 2015Oct 30 2015We report the detection of 48 millisecond pulsars (MSPs) out of 75 observed thus far using the LOFAR in the frequency range 110-188 MHz. We have also detected three MSPs out of nine observed in the frequency range 38-77 MHz. This is the largest sample ... More
Geomagnetic origin of the radio emission from cosmic ray induced air showers observed by CODALEMAJan 28 2009The new setup of the CODALEMA experiment installed at the Radio Observatory in Nancay, France, is described. It includes broadband active dipole antennas and an extended and upgraded particle detector array. The latter gives access to the air shower energy, ... More
Radio emission of extensive air shower at CODALEMA: Polarization of the radio emission along the v*B vectorJun 15 2009Jun 17 2009Cosmic rays extensive air showers (EAS) are associated with transient radio emission, which could provide an efficient new detection method of high energy cosmic rays, combining a calorimetric measurement with a high duty cycle. The CODALEMA experiment, ... More
The active muon shield in the SHiP experimentMar 10 2017May 18 2017The SHiP experiment is designed to search for very weakly interacting particles beyond the Standard Model which are produced in a 400 GeV/c proton beam dump at the CERN SPS. An essential task for the experiment is to keep the Standard Model background ... More
LOFAR 150-MHz observations of SS 433 and W 50Feb 09 2018We present LOFAR high-band data over the frequency range 115-189 MHz for the X-ray binary SS 433, obtained in an observing campaign from 2013 February - 2014 May. Our results include a deep, wide-field map, allowing a detailed view of the surrounding ... More
The ASKAP/EMU Source Finding Data ChallengeSep 14 2015The Evolutionary Map of the Universe (EMU) is a proposed radio continuum survey of the Southern Hemisphere up to declination +30 deg., with the Australian Square Kilometre Array Pathfinder (ASKAP). EMU will use an automated source identification and measurement ... More
Low-radio-frequency eclipses of the redback pulsar J2215+5135 observed in the image plane with LOFARApr 19 2016The eclipses of certain types of binary millisecond pulsars (i.e. `black widows' and `redbacks') are often studied using high-time-resolution, `beamformed' radio observations. However, they may also be detected in images generated from interferometric ... More
The shape of the Photon Transfer Curve of CCD sensorsMay 21 2019The Photon Transfer Curve (PTC) of a CCD depicts the variance of uniform images as a function of their average. It is now well established that the variance is not proportional to the average, as Poisson statistics would indicate, but rather flattens ... More
The Unusual Binary Pulsar PSR J1744-3922: Radio Flux Variability, Near-infrared Observation and EvolutionFeb 13 2007PSR J1744-3922 is a binary pulsar exhibiting highly variable pulsed radio emission. We report on a statistical multi-frequency study of the pulsed radio flux variability which suggests that this phenomenon is extrinsic to the pulsar and possibly tied ... More
Determining surface rotation periods of solar-like stars observed by the Kepler mission using machine learning techniquesJun 23 2019For a solar-like star, the surface rotation evolves with time, allowing in principle to estimate the age of a star from its surface rotation period. Here we are interested in measuring surface rotation periods of solar-like stars observed by the NASA ... More