Results for "R. Harris"

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The Metallicity Distribution in the Outer Halo of M33Jun 10 2004We present the results of deep I and V-band photometry of the halo stars near the southeast minor axis of the Local Group spiral galaxy M33. An (I,V-I) color-magnitude diagram distinctly reveals the red giant branch stars at the bright end of the color-magnitude ... More
Strong Law of Large Numbers for Fragmentation ProcessesSep 17 2008In the spirit of a classical results for Crump-Mode-Jagers processes, we prove a strong law of large numbers for homogenous fragmentation processes. Specifically, for self-similar fragmentation processes, including homogenous processes, we prove the almost ... More
Risk Apportionment: The Dual StoryDec 06 2017By specifying model free preferences towards simple nested classes of lottery pairs, we develop the dual story to stand on equal footing with that of (primal) risk apportionment. The dual story provides an intuitive interpretation, and full characterization, ... More
The Combinatorial Data Fusion Problem in Conflicted-supervised LearningSep 24 2018The best merge problem in industrial data science generates instances where disparate data sources place incompatible relational structures on the same set $V$ of objects. Graph vertex labelling data may include (1) missing or erroneous labels,(2) assertions ... More
Critical Test of Simulations of Charge-Exchange-Induced X-Ray Emission in the Solar SystemMay 14 2010Experimental and theoretical state-selective X-ray spectra resulting from single-electron capture in charge exchange (CX) collisions of Ne^10+ with He, Ne, and Ar are presented for a collision velocity of 933 km s^-1 (4.54 keV nucleon^-1), comparable ... More
Upper semicontinuity of the lamination hullSep 30 2016Let $K \subseteq \mathbb{R}^{2 \times 2}$ be a compact set, let $K^{rc}$ be its rank-one convex hull, and let $L(K)$ be its lamination convex hull. It is shown that the mapping $K \to \overline{L(K)}$ is not upper semicontinuous on the diagonal matrices ... More
Comparison of Attitude Estimation Techniques for Low-cost Unmanned Aerial VehiclesFeb 24 2016Attitude estimation for small, low-cost unmanned aerial vehicles is often achieved using a relatively simple complementary filter that combines onboard accelerometers, gyroscopes, and magnetometer sensing. This paper explores the limits of performance ... More
Classification of the monomial Cremona transformations of the planeJul 24 2014We classify all monomial planar Cremona maps by multidegree using recent methods developed by Aluffi. Following the main result, we prove several more properties of the set of these maps, and also extend the results to the more general `r.c. monomial' ... More
The kernel of the monodromy of the universal family of degree $d$ smooth plane curvesApr 23 2019We consider the parameter space $\mathcal U_d$ of smooth plane curves of degree $d$. The universal smooth plane curve of degree $d$ is a fiber bundle $\cal E_d\to\cal U_d$ with fiber diffeomorphic to a surface $\Sigma_g$. This bundle gives rise to a monodromy ... More
On a linearized p-Laplace equation with rapidly oscillating coefficientsJun 15 2015Nov 19 2015Related to a conjecture of Tom Wolff, we solve a singular Neumann problem for a linearized p-Laplace equation in the unit disk.
Self-field and magnetic-flux quantum mechanicsApr 06 2005Self-field and quantized magnetic-flux are employed to generate the quantum numbers n, m, and l of atomic physics. Wave-particle duality is shown to be a natural outcome of having a particle and its self-field.
Weighted Norm Estimates and Representation Formulas for Rough Singular IntegralsJul 16 1998Weighted norm estimates and representation formulas are proved for non-homogeneous singular integrals with no regularity condition on the kernel and only an L log L integrability condition. The representation formulas involve averages over a star-shaped ... More
Incorrigible RepresentationsNov 12 2018Dec 25 2018As a consequence of his numerical local Langlands correspondence for $GL(n)$, Henniart deduced the following theorem: If $F$ is a nonarchimedean local field and if $\pi$ is an irreducible admissible representation of $GL(n,F)$, then, after a finite sequence ... More
Optimal angle of the holomorphic functional calculus for the classical Ornstein-Uhlenbeck operator on $L^p$Dec 20 2018We give a simple proof of the fact that the classical Ornstein-Uhlenbeck operator $L$ is R-sectorial of angle $arcsin|1-2/p|$ on $L^{p}(\mathbb{R}^{n},\exp(-|x|^2/2)dx)$ (for $1<p<\infty$). Applying the abstract holomorphic functional calculus theory ... More
Kostant's weight multiplicity formula and the Fibonacci numbersNov 28 2011It is well known that the dimension of a weight space for a finite dimensional representation of a simple Lie algebra is given by Kostant's weight multiplicity formula. We address the question of how many terms in the alternation contribute to the multiplicity ... More
Observation Of Repetition-Rate Dependent Emission From an Un-Gated Thermionic Cathode RF GunFeb 24 2017Recent work at Fermilab in collaboration with the Advanced Photon Source and members of other national labs, designed an experiment to study the relationship between the RF repetition rate and the average current per RF pulse. While existing models anticipate ... More
Correlations between Ground and Excited State Spectra of a Quantum DotSep 10 1997Oct 30 1997We have studied the ground and excited state spectra of a semiconductor quantum dot for successive numbers of electron occupancy using linear and nonlinear magnetoconductance measurements. We present the first observation of direct correlation between ... More
Diamonds on the Hat: Globular Clusters in The Sombrero Galaxy (M104)Sep 25 2009Images from the HST ACS are used to carry out a new photometric study of the globular clusters (GCs) in M104, the Sombrero galaxy. The primary focus of our study is the characteristic distribution function of linear sizes (SDF) of the GCs. We measure ... More
The Refined Gross-Prasad Conjecture for Unitary GroupsJan 02 2012Sep 08 2012Let F be a number field, A_F its ring of adeles, and let {\pi}_n and {\pi}_{n+1} be irreducible, cuspidal, automorphic representations of SO_n(A_F) and SO_{n+1}(A_F), respectively. In 1991, Benedict Gross and Dipendra Prasad conjectured the non-vanishing ... More
The escape of heavy atoms from the ionosphere of HD209458b. I. A photochemical-dynamical model of the thermosphereOct 04 2012The detections of atomic hydrogen, heavy atoms and ions surrounding the extrasolar giant planet (EGP) HD209458b constrain the composition, temperature and density profiles in its upper atmosphere. Thus the observations provide guidance for models that ... More
The Effects of Orbital Inclination on the Scale Size and Evolution of Tidally Filling Star ClustersSep 02 2014We have performed N-body simulations of tidally filling star clusters with a range of orbits in a Milky Way-like potential to study the effects of orbital inclination and eccentricity on their structure and evolution. At small galactocentric distances ... More
Detection of a white dwarf companion to the white dwarf SDSSJ125733.63+542850.5Feb 25 2010May 16 2011SDSSJ125733.63+542850.5 (hereafter SDSSJ1257+5428) is a compact white dwarf binary from the Sloan Digital Sky Survey that exhibits high-amplitude radial velocity variations on a period of 4.56 hours. While an initial analysis suggested the presence of ... More
Severi Degrees in Cogenus 3Apr 06 1995In this short note, a new computation of the degree of the locus of 3-nodal plane curves in the linear system of degree d plane curves is given. The answer is expressed as a tautological class on a blow-up of the Hilbert scheme of 3 points in the plane. ... More
New g'r'i'z' Photometry of the NGC 5128 Globular Cluster SystemSep 17 2010Sep 21 2010We present new photometry for 323 of the globular clusters in NGC 5128 (Centaurus A), measured for the first time in the $g'r'i'z'$ filter system. The color indices are calibrated directly to standard stars in the $g'r'i'z'$ system and are used to establish ... More
X-ray Point Sources in the Sombrero Galaxy: Supersoft sources, the globular cluster/LMXB connection, and an overviewJun 22 2003We report on the population of point sources discovered during an 18.5 ksec Chandra ACIS-S observation of the Sombrero Galaxy. We present the luminosity function, the spectra of the 6 brightest sources, consider correlations with globular clusters (GCs) ... More
Low-Temperature Saturation of the Dephasing Time and Effects of Microwave Radiation on Open Quantum DotsApr 20 1999The dephasing time of electrons in open semiconductor quantum dots, measured using ballistic weak localization, is found to saturate below ~ 100 mK, roughly twice the electron base temperature, independent of dot size. Microwave radiation deliberately ... More
Monte Carlo simulations for the optimization and data analysis of experiments with ultracold neutronsJun 28 2018Ultracold neutrons (UCN) with kinetic energies up to 300 neV can be stored in material or magnetic confinements for hundreds of seconds. This makes them a very useful tool for probing fundamental symmetries of nature, by searching for charge-parity violation ... More
On the range of validity of the fluctuation theorem for stochastic Markovian dynamicsNov 21 2007Jun 06 2008We consider the fluctuations of generalized currents in stochastic Markovian dynamics. The large deviations of current fluctuations are shown to obey a Gallavotti-Cohen (GC) type symmetry in systems with a finite state space. However, this symmetry is ... More
Analytic solution of nonlinear fractional Burgers-type equation by invariant subspace methodJun 08 2013In this paper we study the analytic solutions of Burgers-type nonlinear fractional equations by means of the Invariant Subspace Method. We first study a class of nonlinear equations directly related to the time-fractional Burgers equation. Some generalizations ... More
Nonlinear time-fractional dispersive equationsOct 29 2014In this paper we study some cases of time-fractional nonlinear dispersive equations (NDEs) involving Caputo derivatives, by means of the invariant subspace method. This method allows to find exact solutions to nonlinear time-fractional partial differential ... More
Current fluctuations in stochastic systems with long-range memoryApr 09 2009Aug 07 2009We propose a method to calculate the large deviations of current fluctuations in a class of stochastic particle systems with history-dependent rates. Long-range temporal correlations are seen to alter the speed of the large deviation function in analogy ... More
Interkinetic nuclear migration in the zebrafish retina as a diffusive processMar 13 2019A major hallmark of neural development is the oscillatory movement of nuclei between the apical and basal surfaces of the neuroepithelium during the process of interkinetic nuclear migration (IKNM). Here, we employ long-term, rapid lightsheet and two-photon ... More
The Globular Cluster/Central Black Hole Connection in GalaxiesAug 27 2010We explore the relation between the total globular cluster population in a galaxy (N_GC) and the the mass of its central black hole (M_BH). Using a sample of 33 galaxies, twice as large as the original sample discussed by Burkert & Tremaine (2010), we ... More
The Halo Stars in NGC 5128. III: An Inner-Halo Field and the Metallicity DistributionApr 26 2002We present new HST/WFPC2 (V,I) photometry for the red-giant stars in NGC 5128 at a projected distance of 8 kpc from the galaxy center, which probe a mixture of its inner halo and outer bulge. The color-magnitude diagram shows an old red-giant branch which ... More
Deterministic parallel algorithms for fooling polylogarithmic juntas and the Lovasz Local LemmaOct 11 2016Many randomized algorithms can be derandomized efficiently using either the method of conditional expectations or probability spaces with low (almost-) independence. A series of papers, beginning with work by Luby (1988) and continuing with Berger & Rompel ... More
The Moser-Tardos lopsidependency criterion can be stronger than Shearer's criterionOct 06 2016The Lopsided Lov\'{a}sz Local Lemma (LLLL) is a probabilistic tool which is a cornerstone of the probabilistic method of combinatorics, which shows that it is possible to avoid a collection of "bad" events as long as their probabilities and interdependencies ... More
Lopsidependency in the Moser-Tardos framework: Beyond the Lopsided Lovasz Local LemmaOct 07 2016Oct 18 2016The Lopsided Lov\'{a}sz Local Lemma (LLLL) is a powerful probabilistic principle which has been used in a variety of combinatorial constructions. While originally a general statement about probability spaces, it has recently been transformed into a variety ... More
The Laboratory of Material Analysis with Ion Beams, LAMFI-USPFeb 19 2019LAMFI is a laboratory dedicated to the development and application of ion beam techniques for the analysis of bulk materials and thin films. Its main facilities comprise an 1.7MV Pelletron tandem accelerator and two analytical setups, one mainly for Rutherford ... More
A New Catalog of Globular Clusters in the Milky WayDec 15 2010A new revision of the McMaster catalog of Milky Way globular clusters is available. This is the first update since 2003 and the biggest single revision since the original version of the catalog published in 1996. The list now contains a total of 157 objects ... More
UCD Candidates in the Hydra ClusterAug 10 2007NGC 3311, the giant cD galaxy in the Hydra cluster (A1060), has one of the largest globular cluster systems known. We describe new Gemini GMOS (g',i') photometry of the NGC 3311 field which reveals that the red, metal-rich side of its globular cluster ... More
From Supermassive Black Holes to Dwarf Elliptical Nuclei: a Mass ContinuumMar 29 2006Apr 03 2006Considerable evidence suggests that supermassive black holes reside at the centers of massive galactic bulges. At a lower galactic mass range, many dwarf galaxies contain extremely compact nuclei that structurally resemble massive globular clusters. We ... More
Rational curves on hypersurfaces of low degree, IIJul 27 2002This is a continuation of "Rational curves on hypersurfaces of low degree", math.AG/0203088. We prove that if d^2+d+1 < n and d > 2, then for a general hypersurface X_d in P^n of degree d, for each degree e the space of rational curves of degree e on ... More
Performance Analysis of GPU-Accelerated Filter-Based Source Finding for HI Spectral Line Image DataJul 17 2015Searching for sources of electromagnetic emission in spectral-line radio astronomy interferometric data is a computationally intensive process. Parallel programming techniques and High Performance Computing hardware may be used to improve the computational ... More
A Framework for HI Spectral Source Finding Using Distributed-Memory SupercomputingJul 18 2014The latest generation of radio astronomy interferometers will conduct all sky surveys with data products consisting of petabytes of spectral line data. Traditional approaches to identifying and parameterising the astrophysical sources within this data ... More
Upper semicontinuity of the lamination hullSep 30 2016Apr 24 2017Let $K \subseteq \mathbb{R}^{2 \times 2}$ be a compact set, let $K^{rc}$ be its rank-one convex hull, and let $L(K)$ be its lamination convex hull. It is shown that the mapping $K \to \overline{L(K)}$ is not upper semicontinuous on the diagonal matrices ... More
A remark on the Schottky locus in genus 4Jan 02 2003We determine the class of the (closure of the) Schottky locus in genus 4 in the Igusa- and the Voronoi compactification of A_4 and comment on the weight 8 modular form which vanishes on it.
Measure changes with extinctionNov 11 2008Dec 18 2008We consider a change of measure by a martingale $Z_t$ and clarify that in general $1/Z_t$ is only a supermartingale under the changed measure. We then give a necessary and sufficient condition for the event that the limit of the martingale is zero to ... More
Bipartite matrix-valued tensor product correlations that are not finitely representableJun 22 2018We consider the matrix-valued generalizations of bipartite tensor product quantum correlations and bipartite infinite-dimensional tensor product quantum correlations, respectively. These sets are denoted by $C_q^{(n)}(m,k)$ and $C_{qs}^{(n)}(m,k)$, respectively, ... More
Multiparametric shell eigenvalue problemsMar 10 2018Mar 16 2018The eigenproblem for thin shells of revolution under uncertainty in material parameters is discussed. Here the focus is on the smallest eigenpairs. Shells of revolution have natural eigenclusters due to symmetries, moreover, the eigenpairs depend on a ... More
Asymptotic convergence of spectral inverse iterations for stochastic eigenvalue problemsJun 12 2017We consider and analyze applying a spectral inverse iteration algorithm and its subspace iteration variant for computing eigenpairs of an elliptic operator with random coefficients. With these iterative algorithms the solution is sought from a finite ... More
Two Formulae for Exterior power operations on higher $K$-groupsJan 14 2019Feb 04 2019Exterior power operations on the higher $K$-groups of a quasi-compact scheme have recently been constructed by Taelman and the authors by purely algebraic means. In this paper, we prove two formulae that help to compute these operations. The first is ... More
A new characterization of the exceptional Lie algebrasMar 13 2014For a simple Lie algebra, over $\mathbb{C}$, we consider the weight which is the sum of all simple roots and denote it $\tilde{\alpha}$. We formally use Kostant's weight multiplicity formula to compute the "dimension" of the zero-weight space. In type ... More
On-off Threshold Models of Social ContagionSep 10 2012We study binary state contagion dynamics on a social network where nodes act in response to the average state of their neighborhood. We model the competing tendencies of imitation and non-conformity by incorporating an off-threshold into standard threshold ... More
Issues in the Formation of Globular Cluster SystemsJan 21 1998Recent developments relevant to the formation of globular cluster systems in galaxies are discussed, including (1) The age distribution of the oldest Milky Way clusters, (2) Subgroups and possible accretion and merger remnants in the Galactic halo, (3) ... More
Limits from CGRO/EGRET Data on the Use of Antimatter as a Power Source by Extraterrestrial CivilizationsDec 20 2001Jun 15 2002I argue that the existence of cold antimatter in bulk is not permitted by the Standard Model, so that if a gamma-ray signature from antiproton annihilation were to be detected, it must represent either new physics or the action of intelligence. Time variability ... More
p-adic measures and square roots of triple product L-functionsOct 23 1996Let p be a prime number, and let f, g, and h be three modular forms of weights $\kappa$, $\lambda$, and $\mu$ for $SL(2,\Bbb{Z})$. We suppose $\kappa \geq \lambda + \mu$. In joint work with Kudla, one of the authors obtained a formula for the normalized ... More
A Two Term Truncation of the Multiple Ising Model Coupled to 2d GravityFeb 06 1995We consider a model of p independent Ising spins on a dynamical planar phi-cubed graph. Truncating the free energy to two terms yields an exactly solvable model that has a third order phase transition from a pure gravity region (gamma=-1/2) to a tree-like ... More
Scaling Radio Astronomy Signal Correlation on Heterogeneous Supercomputers Using Various Data Distribution MethodologiesMay 24 2013Next generation radio telescopes will require orders of magnitude more computing power to provide a view of the universe with greater sensitivity. In the initial stages of the signal processing flow of a radio telescope, signal correlation is one of the ... More
An a.e. lower bound for Hausdorff dimension under vertical projections in the Heisenberg groupNov 30 2018Apr 02 2019An improved a.e. lower bound is given for Hausdorff dimension under vertical projections in the first Heisenberg group.
The Chern-Mather class of the multiview varietyJan 24 2017The multiview variety associated to a collection of $N$ cameras records which sequences of image points in $\mathbb{P}^{2N}$ can be obtained by taking pictures of a given world point $x\in\mathbb{P}^3$ with the cameras. In order to reconstruct a scene ... More
Branching Brownian motion: Almost sure growth along unscaled pathsNov 11 2008We give new results on the growth of the number of particles in a dyadic branching Brownian motion which follow within a fixed distance of a path $f:[0,\infty)\to \mathbb{R}$. We show that it is possible to count the number of particles without rescaling ... More
Powers of Ideals and Fibers of MorphismsJul 26 2008Let X\subset PP^n be a projective scheme over a field, and let phi:X --> Y be a finite morphism. Our main result is a formula in terms of global data for the maximum of the Castelnuovo-Mumford regularity of the fibers of \phi, considered as subschemes ... More
Characterizing the invariances of learning algorithms using category theoryMay 06 2019Many learning algorithms have invariances: when their training data is transformed in certain ways, the function they learn transforms in a predictable manner. Here we formalize this notion using concepts from the mathematical field of category theory. ... More
Scaling approach to related disordered stochastic and free-fermion modelsJun 23 2006Jan 03 2007Motivated by mapping from a stochastic system with spatially random rates, we consider disordered non-conserving free-fermion systems using a scaling procedure for the equations of motion. This approach demonstrates disorder-induced localization acting ... More
The origin of high transport spin polarization in La$_{0.7}$Sr$_{0.3} $MnO$_{3}$: direct evidence for minority spin statesNov 10 2000Using the point contact Andreev reflection technique, we have carried out a systematic study of the spin polarization in the colossal magnetoresistive manganite, La$_{0.7}$Sr$_{0.3}$MnO$_{3}$} (LSMO). Surprisingly, we observed a significant increase in ... More
Zero range model of traffic flowApr 26 2005Oct 08 2005A multi--cluster model of traffic flow is studied, in which the motion of cars is described by a stochastic master equation. Assuming that the escape rate from a cluster depends only on the cluster size, the dynamics of the model is directly mapped to ... More
Refined Strichartz inequalities for the wave equationMay 18 2018Jun 08 2018Some analogues of the Schr\"odinger refined Strichartz inequalities (Du, Guth, Li and Zhang) are obtained for the wave equation. These are used to improve the best known $L^2$ fractal Strichartz inequalities for the wave equation in dimensions $d \geq ... More
Segre Class Computation and Practical ApplicationsJun 19 2018May 09 2019Let $X \subset Y$ be closed (possibly singular) subschemes of a smooth projective toric variety $T$. We show how to compute the Segre class $s(X,Y)$ as a class in the Chow group of $T$. Building on this, we give effective methods to compute intersection ... More
Disordered asymmetric simple exclusion process: mean-field treatmentMar 01 2004We provide two complementary approaches to the treatment of disorder in a fundamental nonequilibrium model, the asymmetric simple exclusion process. Firstly, a mean-field steady state mapping is generalized to the disordered case, where it provides a ... More
Modelling the application of integrated photonic spectrographs to astronomyJul 23 2012One of the well-known problems of producing instruments for Extremely Large Telescopes is that their size (and hence cost) scales rapidly with telescope aperture. To try to break this relation alternative new technologies have been proposed, such as the ... More
A direct method for reconstructing inclusions and boundary conditions from electrostatic dataApr 24 2017Feb 22 2018In this paper, we will discuss the use of a Sampling Method to reconstruct impenetrable inclusions from Electrostatic Cauchy data. We consider the case of a perfectly conducting and impedance inclusion. In either case, we show that the Dirichlet to Neumann ... More
The factorization method for a defective region in an anisotropic materialOct 14 2014In this paper we consider the inverse acoustic scattering (in \mathbb{R}^3) or electromagnetic scattering (in \mathbb{R}^2, for the scalar TE-polarization case) problem of reconstructing possibly multiple defective penetrable regions in a known anisotropic ... More
Near field imaging of small isotropic and extended anisotropic scatterersJan 12 2016Jan 17 2017In this paper, we consider two time-harmonic inverse scattering problems of reconstructing penetrable inhomogeneous obstacles from near field measurements. First we appeal to the Born approximation for reconstructing small isotropic scatterers via the ... More
Branching Brownian motion: Almost sure growth along scaled pathsJun 01 2009Apr 21 2010We give a proof of a result on the growth of the number of particles along chosen paths in a branching Brownian motion. The work follows the approach of classical large deviations results, in which paths in $C[0,1]$ are rescaled onto $C[0,T]$ for large ... More
Upper semicontinuity of the lamination hullSep 30 2016Apr 26 2019Let $K \subseteq \mathbb{R}^{2 \times 2}$ be a compact set, let $K^{rc}$ be its rank-one convex hull, and let $L(K)$ be its lamination convex hull. It is shown that the mapping $K \to \overline{L(K)}$ is not upper semicontinuous on the diagonal matrices ... More
NGC 2419, M92, and the Age Gradient in the Galactic HaloJul 03 1997The WFPC2 camera on HST has been used to obtain deep main sequence photometry of the low-metallicity ([Fe/H]=-2.14), outer-halo globular cluster NGC 2419. A differential fit of the NGC 2419 CMD to that of the similarly metal-poor \ standard cluster M92 ... More
An unbiased metric of antiproliferative drug effect in vitroMay 22 2016In vitro cell proliferation assays are widely used in pharmacology, molecular biology, and drug discovery. Using theoretical modeling and experimentation, we show that current antiproliferative drug effect metrics suffer from time-dependent bias, leading ... More
Fourier's law on a one-dimensional optical random latticeMar 19 2010We study the transport properties of a one-dimensional hard-core bosonic lattice gas coupled to two particle reservoirs at different chemical potentials which generate a current flow through the system. In particular, the influence of random fluctuations ... More
First-order phase transitions from poles in asymptotic representations of partition functionsDec 18 2009Mar 26 2010Although partition functions of finite-size systems are always analytic, and hence have no poles, they can be expressed in many cases as series containing terms with poles. Here we show that such poles can be related to linear branches of the entropy, ... More
Fluctuation theorems for stochastic dynamicsFeb 23 2007Aug 02 2007Fluctuation theorems make use of time reversal to make predictions about entropy production in many-body systems far from thermal equilibrium. Here we review the wide variety of distinct, but interconnected, relations that have been derived and investigated ... More
Generalized Thermal Lattice GasesMay 07 1998We show how to employ thermal lattice gas models to describe non-equilibrium phenomena. This is achieved by relaxing the restrictions of the usual micro-canonical ensemble for these models via the introduction of thermal ``demons'' in the style of Creutz. ... More
Double epitaxy of tetragonal and hexagonal phases in the FeSe systemFeb 09 2019Feb 12 2019Epitaxial films which contains more than one crystallographic orientation are of interest due to the possibility of altered magnetic, electrical, and optical properties. Thin films of FeSe have been grown on single-crystal MgO substrates under conditions ... More
Current transmission and nonlinear effects in un-gated thermionic cathode RF gunsMay 03 2017Un-gated thermionic cathode RF guns are well known as a robust source of electrons for many accelerator applications. These sources are in principle scalable to high currents without degradation of the transverse emittance due to control grids but they ... More
Traffic of cytoskeletal motors with disordered attachment ratesJun 24 2008Feb 19 2010Motivated by experimental results on the interplay between molecular motors and tau proteins, we extend lattice-based models of intracellular transport to include a second species of particle which locally influences the motor-filament attachment rate. ... More
Hydrodynamic behaviour of Lattice Boltzmann and Lattice BGK modelsAug 30 1993We present a numerical analysis of the validity of classical and generalized hydrodynamics for Lattice Boltzmann Equation (LBE) and Lattice BGK methods in two and three dimensions, as a function of the collision parameters of these models. Our analysis ... More
A major radio outburst in III Zw 2 with an extremely inverted, millimeter-peaked spectrumJan 27 1999III Zw 2 is a spiral galaxy with an optical spectrum and faint extended radio structure typical of a Seyfert galaxy, but also with an extremely variable, blazar-like radio core. We have now discovered a new radio flare where the source has brightened ... More
Visitors from the Halo: 11 Gyr old White Dwarfs in the Solar NeighborhoodApr 06 2010We report the discovery of three nearby old halo white dwarf candidates in the Sloan Digital Sky Survey (SDSS), including two stars in a common proper motion binary system. These candidates are selected from our 2800 square degree proper motion survey ... More
Enhanced Tunnelling in a Hybrid of Single-Walled Carbon Nanotubes and GrapheneMar 15 2019Transparent and conductive films (TCFs) are of great technological importance. The high transmittance, electrical conductivity and mechanical strength make single-walled carbon nanotubes (SWCNTs) a good candidate for their raw material. Despite the ballistic ... More
Chandra Temperature Map of Abell 754 and Constraints on Thermal ConductionJan 17 2003Feb 10 2003We use Chandra data to derive a detailed gas temperature map of the nearby, hot, merging galaxy cluster A754. Combined with the X-ray and optical images, the map reveals a more complex merger geometry than previously thought, possibly involving more than ... More
An anti-symmetric exclusion process for two particles on an infinite 1D latticeJul 11 2011Oct 10 2011A system of two biased, mutually exclusive random walkers on an infinite 1D lattice is studied whereby the intrinsic bias of one particle is equal and opposite to that of the other. The propogator for this system is solved exactly and expressions for ... More
Hydrodynamics of the zero-range process in the condensation regimeAug 09 2006Dec 11 2006We argue that the coarse-grained dynamics of the zero-range process in the condensation regime can be described by an extension of the standard hydrodynamic equation obtained from Eulerian scaling even though the system is not locally stationary. Our ... More
Astronomical photonics in the context of infrared interferometry and high-resolution spectroscopyAug 08 2016We review the potential of Astrophotonics, a relatively young field at the interface between photonics and astronomical instrumentation, for spectro-interferometry. We review some fundamental aspects of photonic science that drove the emer- gence of astrophotonics, ... More
Brownian walkers within subdiffusing territorial boundariesFeb 04 2011Jun 01 2011Inspired by the collective phenomenon of territorial emergence, whereby animals move and interact through the scent marks they deposit, we study the dynamics of a 1D Brownian walker in a random environment consisting of confining boundaries that are themselves ... More
Reanalysis of the EMC charm production data with extrinsic and intrinsic charm at NLOAug 30 1995Dec 07 1995A calculation of the next-to-leading order exclusive extrinsic charm quark differential distributions in deeply inelastic electroproduction has recently been completed. Using these results we compare the NLO extrinsic contributions to the charm structure ... More
Double epitaxy of tetragonal and hexagonal phases in the FeSe systemFeb 09 2019Epitaxial films which contains more than one crystallographic orientation are of interest due to the possibility of altered magnetic, electrical, and optical properties. Thin films of FeSe have been grown on single-crystal MgO substrates under conditions ... More
Spectrophotometry of the Huygens Region of the Orion Nebula, the Extended Orion Nebula, and M~43; Scattered Light Systematically Distorts Conditions Derived from Emission-LinesAug 05 2010We report on medium resolution spectrophotometry of the Orion Nebula region, including for the first time the Extended Orion Nebula and the nearby M~43. The 49 long slit observations were divided into 99 smaller samples, which have allowed determinations ... More
A combinatorial model for computing volumes of flow polytopesJan 23 2018Apr 02 2019We introduce new families of combinatorial objects whose enumeration computes volumes of flow polytopes. These objects provide an interpretation, based on parking functions, of Baldoni and Vergne's generalization of a volume formula originally due to ... More
A Catalog of Globular Cluster Systems: What Determines the Size of a Galaxy's Globular Cluster Population?Jun 10 2013We present a catalog of 422 galaxies with published measurements of their globular cluster (GC) populations. Of these, 248 are E galaxies, 93 are S0 galaxies, and 81 are spirals or irregulars. Among various correlations of the total number of GCs with ... More
A Color-Magnitude Diagram for a Globular Cluster In the Giant Elliptical Galaxy NGC 5128Jun 30 1998The Hubble Space Telescope has been used to obtain WFPC2 (V,I) photometry for a large sample of stars in the outer halo of the giant elliptical NGC 5128 (d = 4 Mpc). The globular cluster N5128-C44, at the center of the Planetary Camera field, is well ... More
A new method to sum divergent power series: educated matchJun 01 2017Oct 02 2017We present a method to sum Borel- and Gevrey-summable asymptotic series by matching the series to be summed with a linear combination of asymptotic series of known functions that themselves are scaled versions of a single, appropriate, but otherwise unrestricted, ... More