Results for "Yvonne W Lui"

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A Deep Unsupervised Learning Approach Toward MTBI Identification Using Diffusion MRIFeb 08 2018Mild traumatic brain injury (mTBI) is a growing public health problem with an estimated incidence of one million people annually in US. Neurocognitive tests have been used to both assess the patient condition and to monitor the patient progress. This ... More
Bianchi - Euler system for relativistice fluids and Bel - Robinson type energyJun 29 2002We write a first order symmetric hyperbolic system coupling the Riemann with the dynamical acceleration of a relativistic fluid. W determine the associated, coupled, Bel - Robinson energy, and the integral equality that it satisfies.
Einstein Bianchi equations with sourcesNov 07 2005In this article, dedicated to one of the best specialist of the FOSH systems, we couple the Bianchi equations with the equations satisfied by the dynamical acceleration of a charged fluid and the derivatives of the associated Maxwell field.
Einstein-Bianchi Hyperbolic System for General RelativityOct 07 1997Feb 26 1998By employing the Bianchi identities for the Riemann tensor in conjunction with the Einstein equations, we construct a first order symmetric hyperbolic system for the evolution part of the Cauchy problem of general relativity. In this system, the metric ... More
Tevatron LegacyFeb 28 2012Several major milestones and discoveries were attained during the lifetime of the Tevatron proton-antiproton collider at Fermilab, from 1987 to 2011. One of the most important was the discovery of the top quark in 1995, followed by an intense program ... More
An algorithm for computing the canonical bases of higher-level q-deformed Fock spacesSep 14 2006Dec 12 2006We derive a straightening-free algorithm that computes the canonical bases of any higher-level q-deformed Fock space.
An Effective Compactness Theorem for Coxeter GroupsFeb 16 2009Through highly non-constructive methods, works by Bestvina, Culler, Feighn, Morgan, Paulin, Rips, Shalen, and Thurston show that if a finitely presented group does not split over a virtually solvable subgroup, then the space of its discrete and faithful ... More
A conjecture for q-decomposition matrices of cyclotomic v-Schur algebrasMay 18 2005Apr 27 2006The Jantzen sum formula for cyclotomic v-Schur algebras yields an identity for some q-analogues of the decomposition matrices of these algebras. We prove a similar identity for matrices of canonical bases of higher-level Fock spaces. We conjecture then ... More
Canonical bases of higher-level q-deformed Fock spacesJun 09 2006We show that the transition matrices between the standard and the canonical bases of infinitely many weight subspaces of the higher-level q-deformed Fock spaces are equal.
Analytical treatment of neutrino asymmetry equilibration from flavour oscillations in the early universeMar 19 2002Jun 05 2002A recent numerical study by A. D. Dolgov, S. H. Hansen, S. Pastor, S. T. Petcov, G. G. Raffelt, and D. V. Semikoz (DHPPRS) [hep-ph/0201287] found that complete or partial equilibrium between all active neutrino flavours can be achieved before the big ... More
Flows on Simplicial ComplexesJun 11 2012Given a graph $G$, the number of nowhere-zero $\ZZ_q$-flows $\phi_G(q)$ is known to be a polynomial in $q$. We extend the definition of nowhere-zero $\ZZ_q$-flows to simplicial complexes $\Delta$ of dimension greater than one, and prove the polynomiality ... More
Nonparametric Conditional Inference for Regression Coefficients with Application to Configural PolysamplingOct 30 2007We consider inference procedures, conditional on an observed ancillary statistic, for regression coefficients under a linear regression setup where the unknown error distribution is specified nonparametrically. We establish conditional asymptotic normality ... More
On reconstruction of dynamic permeability and tortuosity from data at distinct frequenciesNov 13 2013May 28 2014This article focuses on the mathematical problem of reconstructing dynamic permeability $K(\omega)$ of two-phase composites from data at different frequencies, utilizing the analytic structure of the Stieltjes function representation of $K(\omega)$ derived ... More
T-violation tests for relativity principlesJan 23 2003We consider the implications of a violation of the equivalence principle or of Lorentz invariance in the neutrino sector for the T-asymmetry $\Delta P_T \equiv P(\nu_{\alpha} \to \nu_{\beta}) - P(\nu_{\beta} \to \nu_{\alpha})$ in a three-flavour framework. ... More
Synchronised neutrino oscillations from self interaction and associated applicationsNov 05 2002Nov 11 2002A recent revival of interest in synchronised oscillations due to neutrino--neutrino forward scattering in dense gases has led to two interesting applications with notable outcomes: (i) cosmological bounds on neutrino--antineutrino asymmetries are improved ... More
Relic neutrino asymmetry generation from $ν_α- ν_s$ oscillationsDec 08 2000Active--sterile neutrino oscillations provide a mechanism by which large differences in the neutrino and antineutrino number densities can be created in the early universe. The quantum kinetic equations are employed in the study of these asymmetries, ... More
Optical study of the electronic phase transition of strongly correlated YbInCu_4Jul 10 2000Infrared, visible and near-UV reflectivity measurements are used to obtain conductivity as a function of temperature and frequency in YbInCu_4, which exhibits an isostructural phase-transition into a mixed-valent phase below T_v=42 K. In addition to a ... More
Higher order corrections to the large scale matter power spectrum in the presence of massive neutrinosSep 04 2008Oct 06 2008We present the first systematic derivation of the one-loop correction to the large scale matter power spectrum in a mixed cold+hot dark matter cosmology with subdominant massive neutrino hot dark matter. Starting with the equations of motion for the density ... More
Approximating the Chromatic PolynomialAug 17 2016Chromatic polynomials are important objects in graph theory and statistical physics, but as a result of computational difficulties, their study is limited to graphs that are small, highly structured, or very sparse. We have devised and implemented two ... More
Probing Strong Field Gravity Through Numerical SimulationsFeb 24 2015This article is an overview of the contributions numerical relativity has made to our understanding of strong field gravity, to be published in the book "General Relativity and Gravitation: A Centennial Perspective", commemorating the 100th anniversary ... More
Grain-resolved kinetics and rotation during grain growth of nanocrystalline Aluminium by molecular dynamicsAug 26 2016Nov 15 2016Grain growth in nanocrystalline Al was studied by means of molecular dynamics simulations. The novelty of this study results from the utilization of an algorithm to resolve per-grain kinetics and orientation change from molecular dynamics data sets. To ... More
Collision Avoidance for Bi-Steerable Car Using Analytic Left InversionMar 19 2016A case study is presented of a collision avoidance system that directly integrates the kinematics of a bi-steerable car with a suitable path planning algorithm. The first step is to identify a path using the method of rapidly exploring random trees, and ... More
Future Global in time einsteinian spacetimes with U(1) isometry groupDec 19 2001We prove that spacetimes satisfying the vacuum Einstein equations on a manifold of the form $\Sigma \times U(1)\times R$ where $\Sigma $ is a compact surface of genus $G>1$ and where the Cauchy data is invariant with respect to U(1) and sufficiently small ... More
Global Hyperbolicity and CompletenessJan 17 2002Jan 21 2002We prove global hyperbolicity of spacetimes under generic regularity conditions on the metric. We then show that these spacetimes are timelike and null geodesically complete if the gradient of the lapse and the extrinsic curvature $K$ are integrable. ... More
Motion of Isolated bodiesMay 17 2006It is shown that sufficiently smooth initial data for the Einstein-dust or the Einstein-Maxwell-dust equations with non-negative density of compact support develop into solutions representing isolated bodies in the sense that the matter field has spatially ... More
The Influence of Bars on Nuclear ActivityApr 11 1997We test ideas on fueling of galactic nuclei by bar-driven inflow by comparing the detection rate and intensity of nuclear H II regions and AGNs among barred and unbarred galaxies in a sample of over 300 spirals selected from our recent optical spectroscopic ... More
Finite Volume Modeling of Poroelastic-Fluid Wave Propagation with Mapped GridsMay 13 2013In this work we develop a high-resolution mapped-grid finite volume method code to model wave propagation in two dimensions in systems of multiple orthotropic poroelastic media and/or fluids, with curved interfaces between different media. We use a unified ... More
Relic neutrino clustering and implications for their detectionDec 17 2004We study the gravitational clustering of big bang relic neutrinos onto existing cold dark matter and baryonic structures within the flat $\Lambda$CDM model. We then discuss the implications of clustering for scattering-based relic neutrino detection methods, ... More
Evolutionary Transitions and Top-Down CausationJul 19 2012Top-down causation has been suggested to occur at all scales of biological organization as a mechanism for explaining the hierarchy of structure and causation in living systems. Here we propose that a transition from bottom-up to top-down causation -- ... More
Nonextensive Thermostatistics and the $H$-Theorem RevisitedMar 02 2004In this paper we present a new derivation of the $H$-theorem and the corresponding collisional equilibrium velocity distributions, within the framework of Tsallis' nonextensive thermostatistics. Unlike previous works, in our derivation we do not assume ... More
Top Quark Physics at the TevatronFeb 14 2013Mar 26 2013The heaviest known elementary particle, the top quark, was discovered in 1995 by the CDF and D0 collaborations at the Tevatron proton-antiproton collider at Fermilab. Since its discovery, a large program was set in motion by the CDF and D0 collaborations ... More
Cauchy problem with data on a characteristic cone for the Einstein-Vlasov equationsJun 02 2012We show how to solve the Cauchy problem for the Einstein-Vlasov equations with geometric initial data on a light-cone.
Origin of quasi-periodic shells in dust forming AGB windsMar 21 2001We have combined time dependent hydrodynamics with a two-fluid model for dust driven AGB winds. Our calculations include self-consistent gas chemistry, grain formation and growth, and a new implementation of the viscous momentum transfer between grains ... More
The effect of grain drift on the structure of (Post-) AGB windsSep 29 1999We have developed an implementation for the momentum transfer force in numerical two fluid hydrodynamics. This form of the frictional coupling between gas and grains is consistent with the microscopic interactions between the two components. The coupling ... More
Applications of theorems of Jean Leray to the Einstein-scalar field equationsNov 02 2006The Einstein-scalar field theory can be used to model gravitational physics with scalar field matter sources. We discuss the initial value formulation of this field theory, and show that the ideas of Leray can be used to show that the Einstein-scalar ... More
The Einstein-scalar field constraints on asymptotically Euclidean manifoldsJun 20 2005We use the conformal method to obtain solutions of the Einstein-scalar field gravitational constraint equations. Handling scalar fields is a bit more challenging than handling matter fields such as fluids, Maxwell fields or Yang-Mills fields, because ... More
Dendriform-Tree Setting for Fully Non-commutative Fliess OperatorsAug 29 2014This paper provides a dendriform-tree setting for Fliess operators with matrix-valued inputs. This class of analytic nonlinear input-output systems is convenient, for example, in quantum control. In particular, a description of such Fliess operators is ... More
On the geometry of moduli spaces of holomorphic chains over compact Riemann surfacesDec 21 2005We study holomorphic $(n+1)$-chains $E_n\to E_{n-1} \to >... \to E_0$ consisting of holomorphic vector bundles over a compact Riemann surface and homomorphisms between them. A notion of stability depending on $n$ real parameters was introduced in the ... More
A Search for "Dwarf" Seyfert Nuclei. V. Demographics of Nuclear Activity in Nearby GalaxiesApr 11 1997We use the sample of emission-line nuclei derived from a recently completed optical spectroscopic survey of nearby galaxies to quantify the incidence of local (z = 0) nuclear activity. Consistent with previous studies, we find detectable amounts of ionized ... More
Effects of CMB temperature uncertainties on cosmological parameter estimationSep 27 2007Mar 20 2008We estimate the effect of the experimental uncertainty in the measurement of the temperature of the cosmic microwave background (CMB) on the extraction of cosmological parameters from future CMB surveys. We find that even for an ideal experiment limited ... More
Energy-dependent solar neutrino flux depletion in the Exact Parity Model and implications for SNO, SuperKamiokande and BOREXINOMar 26 1998Aug 24 1998Energy-dependent solar neutrino flux reduction caused by the Mikheyev-Smirnov-Wolfenstein (MSW) effect is applied to the Exact Parity Model. Several scenarios are possible, depending on the region of parameter space chosen. The interplay between intergenerational ... More
Further studies on relic neutrino asymmetry generation I: the adiabatic Boltzmann limit, non-adiabatic evolution, and the classical harmonic oscillator analogue of the quantum kinetic equationsJul 18 2000Aug 15 2000We demonstrate that the relic neutrino asymmetry evolution equation derived from the quantum kinetic equations (QKEs) reduces to the Boltzmann limit that is dependent only on the instantaneous neutrino number densities, in the adiabatic limit in conjunction ... More
Multi-species network inference improves gene regulatory network reconstruction for early embryonic development in DrosophilaJul 24 2014Dec 08 2014Gene regulatory network inference uses genome-wide transcriptome measurements in response to genetic, environmental or dynamic perturbations to predict causal regulatory influences between genes. We hypothesized that evolution also acts as a suitable ... More
Request Complexity of VNet Topology Extraction: Dictionary-Based AttacksApr 21 2013The network virtualization paradigm envisions an Internet where arbitrary virtual networks (VNets) can be specified and embedded over a shared substrate (e.g., the physical infrastructure). As VNets can be requested at short notice and for a desired time ... More
A Search for "Dwarf" Seyfert Nuclei. VI. Properties of Emission-Line Nuclei in Nearby GalaxiesOct 02 2002We use the database from Paper III to quantify the global and nuclear properties of emission-line nuclei in the Palomar spectroscopic survey of nearby galaxies. We show that the host galaxies of Seyferts, LINERs, and transition objects share remarkably ... More
A Search for "Dwarf" Seyfert Nuclei. III. Spectroscopic Parameters and Properties of the Host GalaxiesApr 11 1997We have completed an optical spectroscopic survey of the nuclear regions (r < 200 pc) of a large sample of nearby galaxies. Although the main objectives of the survey are to search for low-luminosity active galactic nuclei and to quantify their luminosity ... More
Low-Luminosity Seyfert NucleiJul 23 1996We describe a new sample of Seyfert nuclei discovered during the course of an optical spectroscopic survey of nearby galaxies. The majority of the objects, many recognized for the first time, have luminosities much lower than those of classical Seyferts ... More
Transport properties of graphene quantum dotsApr 04 2011In this work we present a theoretical study of transport properties of a double crossbar junction composed by segments of graphene ribbons with different widths forming a graphene quantum dot structure. The systems are described by a single-band tight ... More
VLA Detection of the Ionized Stellar Winds Arising from Massive Stars in the Galactic Center Arches ClusterMar 08 2001The Galactic center Arches stellar cluster, detected and studied until now only in the near-infrared, is comprised of at least one hundred massive (M>20 Msun) stars. Here we report the detection at centimeter wavelengths of radio continuum emission from ... More
Discrete-Time Approximations of Fliess OperatorsOct 24 2015A convenient way to represent a nonlinear input-output system in control theory is via a Chen-Fliess functional expansion or Fliess operator. The general goal of this paper is to describe how to approximate Fliess operators with iterated sums and to provide ... More
The post-AGB evolution of AGB mass loss variationsMay 20 2003We present new numerical hydrodynamical modelling of the evolution of Asymptotic Giant Branch (AGB) mass loss fluctuations during the post-AGB/Planetary Nebula phase. These models show that after ionization, the observable effects of the mass loss fluctuations ... More
Properties of H II Regions in the Centers of Nearby GalaxiesApr 11 1997As part of an optical spectroscopic survey of nearby, bright galaxies, we have identified a sample of over 200 emission-line nuclei having optical spectra resembling those of giant extragalactic H II regions. Such "H II nuclei," powered by young, massive ... More
$h$-vectors of small matroid complexesJun 13 2011Stanley conjectured in 1977 that the $h$-vector of a matroid simplicial complex is a pure $O$-sequence. We give simple constructive proofs that the conjecture is true for matroids of rank less than or equal to 3, and corank 2. We used computers to verify ... More
Misleading Stars: What Cannot Be Measured in the Internet?May 26 2011Jun 19 2011Traceroute measurements are one of our main instruments to shed light onto the structure and properties of today's complex networks such as the Internet. This paper studies the feasibility and infeasibility of inferring the network topology given traceroute ... More
Measurement and Control of Quasiparticle Dynamics in a Superconducting QubitJun 27 2014Oct 24 2014Superconducting circuits have attracted growing interest in recent years as a promising candidate for fault-tolerant quantum information processing. Extensive efforts have always been taken to completely shield these circuits from external magnetic field ... More
A Schrodinger Cat Living in Two BoxesJan 21 2016Quantum superpositions of distinct coherent states in a single-mode harmonic oscillator, known as "cat states", have been an elegant demonstration of Schrodinger's famous cat paradox. Here, we realize a two-mode cat state of electromagnetic fields in ... More
Large Scale Flows from Orion-SouthJan 22 2007Multiple optical outflows are known to exist in the vicinity of the active star formation region called Orion-South (Orion-S). We have mapped the velocity of low ionization features in the brightest part of the Orion Nebula, including Orion-S, and imaged ... More
A Survey of Proper Motion Stars. XVII. A Deficiency of Binary Stars on Retrograde Galactic Orbits and the Possibility that omega Centauri is Related to the EffectDec 05 2004We find a deficiency of binary stars moving on strongly retrograde Galactic orbits. No binary deficiencies are seen for U or W velocities, however. From theoretical analyses, we rule out preferential disruption of pre-existing binary stars due to encounters ... More
Z-bursts from the Virgo clusterMay 27 2005Sep 02 2005Resonant annihilation of ultra-high energy cosmic neutrinos (UHECnu) on the cosmic neutrino background (CnuB) into Z bosons--the Z-burst mechanism--and its associated absorption and emission phenomenology provide a unique, albeit indirect, probe of the ... More
Neutrinos in Non-linear Structure Formation - The Effect on Halo PropertiesApr 23 2010We use N-body simulations to find the effect of neutrino masses on halo properties, and investigate how the density profiles of both the neutrino and the dark matter components change as a function of the neutrino mass. We compare our neutrino density ... More
Loop Integrands for Scattering Amplitudes from the Riemann SphereJul 01 2015Sep 10 2015The scattering equations on the Riemann sphere give rise to remarkable formulae for tree-level gauge theory and gravity amplitudes. Adamo, Casali and Skinner conjectured a one-loop formula for supergravity amplitudes based on scattering equations on a ... More
On the Windfall and Price of Friendship: Inoculation Strategies on Social NetworksJan 09 2011Jan 11 2011This article investigates selfish behavior in games where players are embedded in a social context. A framework is presented which allows us to measure the Windfall of Friendship, i.e., how much players benefit (compared to purely selfish environments) ... More
Einstein constraints on a characteristic coneFeb 07 2010We analyse the Cauchy problem on a characteristic cone, including its vertex, for the Einstein equations in arbitrary dimensions. We use a wave map gauge, solve the obtained constraints and show gauge conservation.
The light-cone theoremMay 13 2009Jun 11 2009We prove that the area of cross-sections of light-cones, in space-times satisfying suitable energy conditions, is smaller than or equal to that of the corresponding cross-sections in Minkowski, or de Sitter, or anti-de Sitter space-time. The equality ... More
High-Resolution Finite Volume Modeling of Wave Propagation in Orthotropic Poroelastic MediaMay 25 2012Nov 27 2012Poroelasticity theory models the dynamics of porous, fluid-saturated media. It was pioneered by Maurice Biot in the 1930s through 1960s, and has applications in several fields, including geophysics and modeling of in vivo bone. A wide variety of methods ... More
Top Quark Mass Measurements at the TevatronSep 23 2013Since the discovery of the top quark in 1995 by the CDF and D0 collaborations at the Fermilab Tevatron proton antiproton collider, precise measurements of its mass are ongoing. Using data recorded by the D0 and CDF experiment, corresponding to up to the ... More
Knowledge Acquisition for Content SelectionFeb 24 1997An important part of building a natural-language generation (NLG) system is knowledge acquisition, that is deciding on the specific schemas, plans, grammar rules, and so forth that should be used in the NLG system. We discuss some experiments we have ... More
An in-depth study of grid-based asteroseismic analysisSep 15 2010Jan 20 2011NASA's Kepler mission is providing basic asteroseismic data for hundreds of stars. One of the more common ways of determining stellar characteristics from these data is by so-called "grid based" modelling. We have made a detailed study of grid-based analysis ... More
Getting leverage on inflation with a large photometric redshift surveySep 11 2014We assess the potential of a future large-volume photometric redshift survey to constrain observational inflationary parameters using three large-scale structure observables: the angular shear and galaxy power spectra, and the cluster mass function measured ... More
The Many Faces of Graph DynamicsJun 04 2015Oct 20 2016The topological structure of complex networks has fascinated researchers for several decades, resulting in the discovery of many universal properties and reoccurring characteristics of different kinds of networks. However, much less is known today about ... More
On the Evans-Krylov theoremMay 08 2009Sep 08 2010In this note, motivated by our work on integral fully nonlinear equations, we provide a variation of the proof of Evans-Krylov theorem about the interior $C^{2,\alpha}$ a priori estimate for concave fully nonlinear elliptic equations. The proof we present ... More
A non local Monge-Ampere equationOct 01 2014Jun 26 2015We introduce a non local analog to the Monge-Ampere operator and show some of its properties. We prove that a global problem involving this operator has C 1,1 solutions in the full space.
Single Top Quark Production at the TevatronOct 26 2012While the heaviest known elementary particle, the top quark, has been discovered in 1995 by the CDF and D0 collaborations in ttbar events, it took 14 more years until the observation of single top quark production. In this article, we discuss recent studies ... More
Top Quark Pair Production Cross Section at the TevatronSep 25 2015The top quark, discovered in 1995 by the CDF and D0 collaborations at the Tevatron proton antiproton collider at Fermilab, has undergone intense studies in the last 20 years. Currently, CDF and D0 converge on their measurements of top-antitop quark production ... More
Measuring neutrino masses with a future galaxy surveySep 05 2012Nov 07 2012We perform a detailed forecast on how well a Euclid-like photometric galaxy and cosmic shear survey will be able to constrain the absolute neutrino mass scale. Adopting conservative assumptions about the survey specifications and assuming complete ignorance ... More
A note on uniform power connectivity in the SINR modelJun 12 2009Jan 31 2010In this paper we study the connectivity problem for wireless networks under the Signal to Interference plus Noise Ratio (SINR) model. Given a set of radio transmitters distributed in some area, we seek to build a directed strongly connected communication ... More
Measuring neutrino masses and dark energy with weak lensing tomographyMar 01 2006Jun 28 2006Surveys of weak gravitational lensing of distant galaxies will be one of the key cosmological probes in the future. We study the ability of such surveys to constrain neutrino masses and the equation of state parameter of the dark energy, focussing on ... More
Iterated smoothed bootstrap confidence intervals for population quantilesApr 25 2005This paper investigates the effects of smoothed bootstrap iterations on coverage probabilities of smoothed bootstrap and bootstrap-t confidence intervals for population quantiles, and establishes the optimal kernel bandwidths at various stages of the ... More
Boltzmann hierarchy for interacting neutrinos I: formalismSep 04 2014Mar 16 2015Starting from the collisional Boltzmann equation, we derive for the first time and from first principles the Boltzmann hierarchy for neutrinos including interactions with a scalar particle. Such interactions appear, for example, in majoron-like models ... More
Thinning of the Sun's magnetic layer: the peculiar solar minimum could have been predictedAug 27 2012The solar magnetic activity cycle causes changes in the Sun on timescales that are relevant to human lifetimes. The minimum in solar activity that preceded the current solar cycle (cycle 24) was deeper and quieter than any other recent minimum. Using ... More
Production of hypertritons in heavy ion collisions around the threshold of strangeness productionNov 09 2015We use the Isospin Quantum Molecular Dynamics approach supplemented with a phase space coalescence to study the properties of the production of hypertritons. We see strong influences of the hyperon rescattering on the yields. The hypertritons show up ... More
Regularity results for nonlocal equations by approximationFeb 23 2009Mar 30 2010In this paper we prove a nonlocal version of the Cordes-Niremberg estimates. We use it to extend our previous regularity results for fully nonlinear integro-differential equations to the variable coefficient case and several other settings where the equation ... More
Regularity theory for fully nonlinear integro-differential equationsSep 28 2007Apr 26 2008We consider nonlinear integro-differential equations, like the ones that arise from stochastic control problems with purely jump L\`evy processes. We obtain a nonlocal version of the ABP estimate, Harnack inequality, and interior $C^{1,\alpha}$ regularity ... More
An extension problem related to the fractional LaplacianAug 25 2006Feb 13 2007The operator square root of the Laplacian $(-\lap)^{1/2}$ can be obtained from the harmonic extension problem to the upper half space as the operator that maps the Dirichlet boundary condition to the Neumann condition. In this paper we obtain similar ... More
Top Quark Properties at the TeVatronMar 29 2011Discovered in 1995 by CDF and D0 at the Fermilab Tevatron collider, the top quark remains interesting to test the Standard Model. Having collected more than 7 fb$^{-1}$ of integrated luminosity with both experiments until today, several top quark properties ... More
A Bayesian view of the current status of dark matter direct searchesMay 25 2011Sep 13 2011Bayesian statistical methods offer a simple and consistent framework for incorporating uncertainties into a multi-parameter inference problem. In this work we apply these methods to a selection of current direct dark matter searches. We consider the simplest ... More
Spherical collapse of dark energy with an arbitrary sound speedAug 31 2010Apr 27 2012We consider a generic type of dark energy fluid, characterised by a constant equation of state parameter w and sound speed c_s, and investigate the impact of dark energy clustering on cosmic structure formation using the spherical collapse model. Along ... More
From Caesar to Twitter: An Axiomatic Approach to Elites of Social NetworksNov 14 2011Nov 27 2012In many societies there is an elite, a relatively small group of powerful individuals that is well-connected and highly influential. Since the ancient days of Julius Caesar's senate of Rome to the recent days of celebrities on Twitter, the size of the ... More
How CMB and large-scale structure constrain chameleon interacting dark energyMay 12 2015We explore a chameleon type of interacting dark matter-dark energy scenario in which a scalar field adiabatically traces the minimum of an effective potential sourced by the dark matter density. We discuss extensively the effect of this coupling on cosmological ... More
Relic neutrino asymmetry evolution from first principlesSep 14 1998Aug 04 1999The exact Quantum Kinetic Equations for a two-flavour active-sterile neutrino system are used to provide a systematic derivation of approximate evolution equations for the relic neutrino asymmetry. An extension of the adiabatic approximation for matter-affected ... More
The unexplored landscape of two-body resonancesOct 28 2016We propose a strategy for searching for theoretically-unanticipated new physics which avoids a large trials factor by focusing on experimental strengths. Searches for resonances decaying into pairs of visible particles are experimentally very powerful ... More
The Evans-Krylov theorem for non local fully non linear equationsMay 08 2009We prove an interior regularity result for solutions of a purely integro-differential Bellman equation. This regularity is enough for the solutions to be understood in the classical sense. If we let the order of the equation approach two, we recover the ... More
Bloch-Like Quantum Multiple Reflections of AtomsNov 14 1998We show that under certain circumstances an atom can follow an oscillatory motion in a periodic laser profile with a Gaussian envelope. These oscillations can be well explained by using a model of energetically forbidden spatial regions. The similarities ... More
The Central Regions of Early-Type Galaxies Hosting Active Galactic Nuclei as Viewed with HST/NICMOSFeb 28 2001We present preliminary results from surface photometry of a sample of early-type galaxies observed with NICMOS on board HST in the F160W (H-band) filter. Dust is found to occur mostly in galaxies which possess unresolved nuclei, and in a few cases the ... More
Discovery of Radio Outbursts in the Active Nucleus of M81May 06 1999The low-luminosity active galactic nucleus of M81 has been monitored at centimeter wavelengths since early 1993 as a by-product of radio programs to study the radio emission from Supernova 1993J. The extensive data sets reveal that the nucleus experienced ... More
A Search for "Dwarf" Seyfert Nuclei. IV. Nuclei with Broad H-alpha EmissionApr 11 1997We present the results of an optical spectroscopic survey designed to search for low-luminosity, "dwarf" Seyfert nuclei in a magnitude-limited sample of 486 bright, northern galaxies. Moderate-resolution spectra of exceptionally high quality were obtained ... More
Stellar Winds and Embedded Star Formation in the Galactic Center Quintuplet and Arches Clusters: Multifrequency Radio ObservationsAug 08 2005A multi-frequency, multi-configuration study has been made of the compact radio sources in the Galactic Center Quintuplet and Arches stellar clusters using the Very Large Array. Ten radio sources have been detected in the Quintuplet cluster. The majority ... More
The Many Faces of Graph DynamicsAug 05 2016The topological structure of complex networks has fascinated researchers for several decades, resulting in the discovery of many universal properties and reoccurring characteristics of different kinds of networks. However, much less is known today about ... More
Top quark Physics at the TevatronJan 06 2012When the heaviest elementary particle known today, the top quark, was discovered in 1995 by the CDF and D0 collaborations at the Fermilab Tevatron collider, a large program to study this particle in details has started. In this article, an overview of ... More
Is it possible to tell the difference between fermionic and bosonic hot dark matter?Jul 22 2005We study the difference between thermally produced fermionic and bosonic hot dark matter in detail. In the linear regime of structure formation, their distinct free-streaming behaviours can lead to pronounced differences in the matter power spectrum. ... More