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High Dimensional Linear Regression via the R2-D2 Shrinkage PriorAug 31 2016Sep 10 2017We propose a new class of priors for linear regression, the R-square induced Dirichlet Decomposition (R2-D2) prior. The prior is induced by a Beta prior on the coefficient of determination, and then the total prior variance of the regression coefficients ... More

A nonparametric Bayesian test of dependenceJan 28 2015In this article, we propose a new method for the fundamental task of testing for dependence between two groups of variables. The response densities under the null hypothesis of independence and the alternative hypothesis of dependence are specified by ... More

Variational approximations using Fisher divergenceMay 13 2019Modern applications of Bayesian inference involve models that are sufficiently complex that the corresponding posterior distributions are intractable and must be approximated. The most common approximation is based on Markov chain Monte Carlo, but these ... More

Variable selection via penalized credible regions with Dirichlet-Laplace global-local shrinkage priorsFeb 03 2016Aug 31 2016The method of Bayesian variable selection via penalized credible regions separates model fitting and variable selection. The idea is to search for the sparsest solution within the joint posterior credible regions. Although the approach was successful, ... More

High Dimensional Linear Regression via the R2-D2 Shrinkage PriorAug 31 2016We propose a new class of priors for linear regression, the R-square induced Dirichlet Decomposition (R2-D2) prior. The prior is induced by a Beta prior on the coefficient of determination, and then the total prior variance of the regression coefficients ... More

Deep Distribution RegressionMar 14 2019Due to their flexibility and predictive performance, machine-learning based regression methods have become an important tool for predictive modeling and forecasting. However, most methods focus on estimating the conditional mean or specific quantiles ... More

On the Origin of Narrow, Very Long, Straight Jets from Some Newly Forming StarsApr 29 1997Observations have shown the existence of narrow, very long, straight jets emitted by some newly forming stars (1). It is highly likely that stars forming in the plane of a spiral galaxy do so in the presence of an almost uniform magnetic field. In the ... More

An analysis of the FIR/RADIO Continuum Correlation in the Small Magellanic CloudSep 01 2012The local correlation between far-infrared (FIR) emission and radio-continuum (RC) emission for the Small Magellanic Cloud (SMC) is investigated over scales from 3 kpc to 0.01 kpc. Here, we report good FIR/RC correlation down to ~15 pc. The reciprocal ... More

Geodesics and Spanning Trees for Euclidean First-Passage PercolationOct 21 2000The metric $D_\alpha (q,q')$ on the set $Q$ of particle locations of a homogeneous Poisson process on $R^d$, defined as the infimum of $(\sum_i |q_i - q_{i+1}|^\alpha)^{1/\alpha}$ over sequences in $Q$ starting with $q$ and ending with $q'$ (where $| ... More

The uniform general signed rank test and its design sensitivityApr 18 2019A sensitivity analysis in an observational study tests whether the qualitative conclusions of an analysis would change if we were to allow for the possibility of limited bias due to confounding. The design sensitivity of a hypothesis test quantifies the ... More

Straight Line Orbits in Hamiltonian FlowsMar 28 2009We investigate periodic straight-line orbits (SLO) in Hamiltonian force fields using both direct and inverse methods. A general theorem is proven for natural Hamiltonians quadratic in the momenta in arbitrary dimension and specialized to two and three ... More

Wetting of crossed fibers: multiple steady states and symmetry breakingMar 05 2014We investigate the wetting properties of the simplest element of an array of random fibers: two rigid fibers crossing with an inclination angle and in contact with a droplet of a perfectly wetting liquid. We show experimentally that the liquid adopts ... More

Operator-Valued Frames for the Heisenberg GroupSep 27 2014A classical result of Duffin and Schaeffer gives conditions under which a discrete collection of characters on $\mathbb{R}$, restricted to $E = (-1/2, 1/2)$, forms a Hilbert-space frame for $L^2(E)$. For the case of characters with period one, this is ... More

Doppler Resilient Waveforms with Perfect AutocorrelationMar 12 2007We describe a method of constructing a sequence of phase coded waveforms with perfect autocorrelation in the presence of Doppler shift. The constituent waveforms are Golay complementary pairs which have perfect autocorrelation at zero Doppler but are ... More

Photon Acceleration in a Flying FocusApr 30 2019A high-intensity laser pulse propagating through a medium triggers an ionization front that can accelerate and frequency-upshift the photons of a second pulse. The maximum upshift is ultimately limited by the accelerated photons outpacing the ionization ... More

A Conjecture of TrautmanFeb 01 2019In 1998 the physicist Andre Trautman conjectured that a three-dimensional CR manifold is locally realizable if and only if its canonical bundle admits a closed nowhere zero section. We review the relevant definitions, give the physical context, and outline ... More

Displacement cascades and defects annealing in tungsten, Part I: defect database from molecular dynamics simulationsApr 25 2014Molecular dynamics simulations have been used to generate a comprehensive database of surviving defects due to displacement cascades in bulk tungsten. Twenty one data points of primary knock-on atom (PKA) energies ranging from 100 eV (sub-threshold energy) ... More

J plots: a new method for characterizing structures in the interstellar mediumMar 05 2018Large scale surveys have brought about a revolution in astronomy. To analyse the resulting wealth of data, we need automated tools to identify, classify, and quantify the important underlying structures. We present here a method for classifying and quantifying ... More

Representations of monomial algebras have poly-exponential complexitiesNov 16 2010Nov 20 2010We use directed graphs called "syzygy quivers" to study the asymptotic growth rates of the dimensions of the syzygies of representations of finite dimensional algebras. For any finitely generated representation of a monomial algebra, we show that this ... More

Convex Bodies of Constant Width and Constant BrightnessJun 30 2003In 1926 S. Nakajima (= A. Matsumura) showed that any convex body in $\R^3$ with constant width, constant brightness, and boundary of class $C^2$ is a ball. We show that the regularity assumption on the boundary is unnecessary, so that balls are the only ... More

The Elliptical EnvelopeMar 02 2007This article considers a one-parameter family of circles F_C, which has the interesting property that the null isocline of the family is the largest member of the family. This family of circles is bounded and we consider the problem of deriving an equation ... More

On an Algorithm of FriezeFeb 20 2001May 29 2002The algorithm reduces the running time of an algorithm of Frieze from O(n^{1.5)) to O(n^(4/3 + o)). It also introduces the concept of admissible permutations that is used in algorithms for obtaining solutions to the AP and the TSP.

The Oblique Orbit of the Super-Neptune HAT-P-11bSep 28 2010We find the orbit of the Neptune-sized exoplanet HAT-P-11b to be highly inclined relative to the equatorial plane of its host star. This conclusion is based on spectroscopic observations of two transits, which allowed the Rossiter-McLaughlin effect to ... More

LHS6343C: A Transiting Field Brown Dwarf Discovered by the Kepler MissionAug 24 2010Nov 30 2010We report the discovery of a brown dwarf that transits one member of the M+M binary system LHS6343AB every 12.71 days. The transits were discovered using photometric data from the Kelper public data release. The LHS6343 stellar system was previously identified ... More

Forming the Borromean Rings out of arbitrary polygonal unknotsJun 12 2014We prove the perhaps surprising result that given any three polygonal unknots in $\R^3$, then we may form the Borromean rings out of them through rigid motions of $\R^3$ applied to the individual components together with possible scaling of the components. ... More

Radio Weak BL Lac objects in the Fermi eraJan 21 2017The existence of "radio weak BL Lac objects" (RWBLs) has been an open question, still unsolved, since the discovery that quasars could be radio-quiet or radio-loud. Recently several groups identified RWBL candidates, mostly found while searching for low ... More

Submodularity and Optimality of Fusion Rules in Balanced Binary Relay TreesOct 16 2012We study the distributed detection problem in a balanced binary relay tree, where the leaves of the tree are sensors generating binary messages. The root of the tree is a fusion center that makes the overall decision. Every other node in the tree is a ... More

Resolving the era of river-forming climates on Mars using stratigraphic logs of river-deposit dimensionsMay 30 2017River deposits are one of the main lines of evidence that tell us that Mars once had a climate different from today, and so changes in river deposits with time tell us something about how Mars climate changed with time. In this study, we focus in on one ... More

Object Kinetic Monte Carlo Simulations of Radiation Damage in Bulk Tungsten Part-II: With a PKA Spectrum Corresponding to 14-MeV NeutronsJun 04 2016Object kinetic Monte Carlo was employed to study the effect of dose rate on the evolution of vacancy microstructure in polycrystalline tungsten under neutron bombardment. The evolution was followed up to 1.0 displacement per atom (dpa) with point defects ... More

Our Milky Way as a Pure-Disk Galaxy -- A Challenge for Galaxy FormationMay 03 2010Jul 20 2010Bulges are commonly believed to form in the dynamical violence of galaxy collisions and mergers. Here we model the stellar kinematics of the Bulge Radial Velocity Assay (BRAVA), and find no sign that the Milky Way contains a classical bulge formed by ... More

Learning in Hierarchical Social NetworksMay 30 2012Nov 21 2012We study a social network consisting of agents organized as a hierarchical M-ary rooted tree, common in enterprise and military organizational structures. The goal is to aggregate information to solve a binary hypothesis testing problem. Each agent at ... More

The California-Kepler Survey. IV. Metal-rich Stars Host a Greater Diversity of PlanetsDec 11 2017Jan 21 2018Probing the connection between a star's metallicity and the presence and properties of any associated planets offers an observational link between conditions during the epoch of planet formation and mature planetary systems. We explore this connection ... More

Carbon in the Draco Dwarf Spheroidal GalaxyMar 13 2013Measurements of [C/Fe], [Ca/H], and [Fe/H] have been derived from Keck I LRISb spectra of 35 giants in the Draco dwarf spheroidal galaxy. The iron abundances are derived by a spectrum synthesis modeling of the wavelength region from 4850 to 5375 A, while ... More

Object Kinetic Monte Carlo Simulations of Radiation Damage in Neutron-Irradiated Tungsten Part-I: Neutron Flux with a PKA Spectrum Corresponding to the High-flux Isotope ReactorOct 09 2015Mar 25 2016Object kinetic Monte Carlo simulations were performed to study the impact of varying dose rate and grain size up to a dose of 1.0 dpa in pure, polycrystalline tungsten, subjected to a neutron irradiation having a PKA spectrum corresponding to the High ... More

Displacement cascades and defects annealing in tungsten, Part II: Object kinetic Monte Carlo Simulation of Tungsten Cascade AgingApr 21 2014We describe the results of object kinetic Monte Carlo (OKMC) simulations of the annealing of primary cascade damage in bulk tungsten using a comprehensive database of cascades obtained from molecular dynamics [1] as a function of primary knock-on atom ... More

The Molecular Gas-Star Formation Connection in an Optically-Selected Sample of Interacting GalaxiesNov 10 1999We have obtained CO(1-0) observations for a sample of 37 interacting galaxy systems, chosen from a parent sample of optically-selected interacting galaxies. The sample observed here spans a large range of interaction strengths and star formation rates ... More

The Bulge Radial Velocity Assay (BRAVA): I. Sample Selection and a Rotation CurveJul 24 2008Results from the Bulge Radial Velocity Assay (BRAVA) are presented. BRAVA uses M giant stars, selected from the 2MASS catalog to lie within a bound of reddening corrected color and luminosity, as targets for the Cerro Tololo Inter-American Observatory ... More

The Bulge Radial Velocity Assay (BRAVA): I. Techniques and a Rotation CurveNov 13 2006Feb 05 2007We are undertaking a large scale radial velocity survey of the Galactic bulge which uses M giant stars selected from the 2MASS catalog as targets for the CTIO 4m Hydra multi-object spectrograph. The aim of this survey is to test dynamical models of the ... More

Method of reconstructing a moving pulseFeb 22 2007Sep 25 2007We present a method of analyzing a set of N time signals f_i(t) that consist of local measurements of the same physical observable taken at N sequential locations Z_i along the length of an experimental device. The result is an algorithm for reconstructing ... More

Orbital Orientations of Exoplanets: HAT-P-4b is Prograde and HAT-P-14b is RetrogradeOct 07 2010Dec 04 2010We present observations of the Rossiter-McLaughlin effect for two exoplanetary systems, revealing the orientations of their orbits relative to the rotation axes of their parent stars. HAT-P-4b is prograde, with a sky-projected spin-orbit angle of lambda ... More

Stability of undercompressive shock profilesAug 11 2004Aug 14 2004Using a simplified pointwise iteration scheme, we establish nonlinear phase-asymptotic orbital stability of large-amplitude Lax, undercompressive, overcompressive, and mixed under--overcompressive type shock profiles of strictly parabolic systems of conservation ... More

A measurement of weak lensing by large scale structure in RCS fieldsFeb 14 2002We have analysed ~24 square degrees of R_C-band imaging data from the Red-Sequence Cluster Survey (RCS), and measured the excess correlations between galaxy ellipticities on scales ranging from 1 to 30 arcminutes. We have used data from two different ... More

The Frequency of Hot Jupiters Orbiting Nearby Solar-Type StarsMay 10 2012We determine the fraction of F, G, and K dwarfs in the Solar Neighborhood hosting hot jupiters as measured by the California Planet Survey from the Lick and Keck planet searches. We find the rate to be 1.2\pm0.38%, which is consistent with the rate reported ... More

Unveiling the nature of the unidentified gamma-ray sources V: analysis of the radio candidates with the kernel density estimationApr 23 2014Nearly one-third of the gamma-ray sources detected by Fermi are still unidentified, despite significant recent progress in this effort. On the other hand, all the gamma-ray extragalactic sources associated in the second Fermi-LAT catalog have a radio ... More

Two-Photon Resonance Fluorescence of a Ladder-Type Atomic SystemJan 02 2019Multi-photon emitters are a sought-after resource in quantum photonics. Nonlinear interactions between a multi-level atomic system and a coherent drive can lead to resonant two-photon emission, but harvesting light from this process has remained a challenge ... More

Precise Radial Velocities of 2046 Nearby FGKM Stars and 131 StandardsJul 26 2012Aug 01 2012We present radial velocities with an accuracy of 0.1 km/s for 2046 stars of spectral type F,G,K, and M, based on 29000 spectra taken with the Keck I telescope. We also present 131 FGKM standard stars, all of which exhibit constant radial velocity for ... More

Stratigraphy of Aeolis Dorsa, Mars: stratigraphic context of the great river depositsDec 10 2017Unraveling the stratigraphic record is the key to understanding ancient climate and past climate changes on Mars. River deposits when placed in stratigraphic order could constrain the number, magnitudes, and durations of the wettest climates in Mars history. ... More

Hubble Space Telescope: Snapshot Survey for Resolved Companions of Galactic CepheidsMar 07 2016We have conducted an imaging survey with the Hubble Space Telescope Wide Field Camera~3 (WFC3) of 70 Galactic Cepheids, typically within 1~kpc, with the aim of finding resolved physical companions. The WFC3 field typically covers the 0.1 pc area where ... More

Phonons and superconductivity in YbC$_6$ and related compoundsSep 15 2010The out-of-plane intercalate phonons of superconducting YbC6 have been measured with inelastic x-ray scattering. Model fits to this data, and previously measured out-of-plane intercalate phonons in graphite intercalation compounds (GICs), reveal surprising ... More

Optical evidence of the chiral magnetic anomaly in Weyl semimetal TaAsOct 12 2018Mar 01 2019Chiral pumping from optical electric fields oscillating at THz frequencies is observed in the Weyl material TaAs with electric and magnetic fields aligned along both the a- and c-axes. Free carrier spectral weight enhancement is measured directly for ... More

Constraints on the Obliquities of Kepler Planet-Hosting StarsOct 12 2017Nov 24 2017Stars with hot Jupiters have obliquities ranging from 0-180 degrees, but relatively little is known about the obliquities of stars with smaller planets. Using data from the California-Kepler Survey, we investigate the obliquities of stars with planets ... More

A hot Jupiter orbiting the 1.7 Msun Subgiant HD102956Jul 26 2010Sep 14 2010We report the detection of a giant planet in a 6.4950 day orbit around the 1.7 Msun subgiant HD102956. The planet has a semimajor axis a = 0.081 AU and minimum mass Msini = 0.96 Mjup. HD102956 is the most massive star known to harbor a hot Jupiter, and ... More

Optical spectroscopic observations of gamma-ray blazar candidates IV. Results of the 2014 follow-up campaignMar 17 2015The extragalactic gamma-ray sky is dominated by the emission arising from blazars, one of the most peculiar classes of radio-loud active galaxies. Since the launch of Fermi several methods were developed to search for blazars as potential counterparts ... More

Super-resolution fluorescence microscopy by stepwise optical saturationJan 10 2018Super-resolution fluorescence microscopy is an important tool in biomedical research for its ability to discern features smaller than the diffraction limit. However, due to its difficult implementation and high cost, the universal application of super-resolution ... More

Mather-Jacobian multiplier ideals on toric varietiesDec 29 2016This paper provides a formula for the Mather-Jacobian multiplier ideals of torus invariant ideals on (not necessarily normal) toric varieties that generalizes Howald's formula for the multiplier ideal of monomial ideals in a polynomial ring.

Pointwise Asymptotic Behavior of Perturbed Viscous Shock ProfilesMar 28 2005Mar 29 2005We consider the asymptotic behavior of perturbations of Lax and overcompressive type viscous shock profiles arising in systems of regularized conservation laws with strictly parabolic viscosity, and also in systems of conservation laws with partially ... More

Pulling subdivisions of cones and blowups of monomial ideals on affine toric varietiesDec 29 2016This short note solves the following problem: Given a map of normal toric varieties corresponding to a coherent subdivision of a cone, find an ideal such that the given map is the blowup of that ideal.

Revolutionaries and SpiesJun 20 2011Aug 06 2012Let $G = (V,E)$ be a graph and let $r,s,k$ be positive integers. "Revolutionaries and Spies", denoted $\cG(G,r,s,k)$, is the following two-player game. The sets of positions for player 1 and player 2 are $V^r$ and $V^s$ respectively. Each coordinate in ... More

K2-97b: A (Re-?)Inflated Planet Orbiting a Red Giant StarJun 19 2016Nov 29 2016Strongly irradiated giant planets are observed to have radii larger than thermal evolution models predict. Although these inflated planets have been known for over fifteen years, it is unclear whether their inflation is caused by deposition of energy ... More

The Stellar Obliquity and the Long-period planet in the HAT-P-17 Exoplanetary SystemJan 26 2013Jul 22 2013We present the measured projected obliquity -- the sky-projected angle between the stellar spin axis and orbital angular momentum -- of the inner planet of the HAT-P-17 multi-planet system. We measure the sky-projected obliquity of the star to be \lambda=19+/-15 ... More

The Red Supergiant Progenitor of Supernova 2012aw (PTF12bvh) in Messier 95Jul 11 2012We report on the direct detection and characterization of the probable red supergiant progenitor of the intermediate-luminosity Type II-Plateau (II-P) supernova (SN) 2012aw in the nearby (10.0 Mpc) spiral galaxy Messier 95 (M95; NGC 3351). We have identified ... More

Retired A Stars and Their Companions: Eighteen New Jovian PlanetsAug 21 2011We report the detection of eighteen Jovian planets discovered as part of our Doppler survey of subgiant stars at Keck Observatory, with follow-up Doppler and photometric observations made at McDonald and Fairborn Observatories, respectively. The host ... More

The California-Kepler Survey V. Peas in a Pod: Planets in a Kepler Multi-planet System are Similar in Size and Regularly SpacedJun 19 2017Feb 07 2018We have established precise planet radii, semimajor axes, incident stellar fluxes, and stellar masses for 909 planets in 355 multi-planet systems discovered by Kepler. In this sample, we find that planets within a single multi-planet system have correlated ... More

Get the News Out Loudly and Quickly: Modeling the Influence of the Media on Limiting Infectious Disease OutbreaksJun 25 2010Mar 21 2011During outbreaks of serious infectious diseases many individuals closely follow media reports of the outbreak and take steps, including self-isolation, to protect themselves from infection and possibly death. Self-isolation can take many forms including ... More

Smooth convex Bodies with proportional projection functionsAug 02 2004For a convex body $K\subset\R^n$ and $i\in\{1,...,n-1\}$, the function assigning to any $i$-dimensional subspace $L$ of $\R^n$, the $i$-dimensional volume of the orthogonal projection of $K$ to $L$, is called the $i$-th projection function of $K$. Let ... More

A short note on the multiplier ideals of monomial space curvesJun 06 2014Nov 11 2015Thompson (2014) exhibits a formula for the multiplier ideal with multiplier lambda of a monomial curve C with ideal I as an intersection of a term coming from the I-adic valuation, the multiplier ideal of the term ideal of I, and terms coming from certain ... More

On a generalization of the generating function for Gegenbauer polynomialsMay 13 2011Jan 17 2013A generalization of the generating function for Gegenbauer polynomials is introduced whose coefficients are given in terms of associated Legendre functions of the second kind. We discuss how our expansion represents a generalization of several previously ... More

Maximal Proper Acceleration and the Quantum-to-Classical TransitionOct 31 2013I first review the physical basis for the universal maximal proper acceleration. Next, I introduce a new formulation for a relativistic scalar quantum field which generalizes the canonical theory to include the limiting proper acceleration. This field ... More

Coarse and synthetic Weil-Petersson geometry: quasi-flats, geodesics, and relative hyperbolicityJul 10 2007Sep 25 2007We analyze the coarse geometry of the Weil-Petersson metric on Teichm\"uller space, focusing on applications to its synthetic geometry (in particular the behavior of geodesics). We settle the question of the strong relative hyperbolicity of the Weil-Petersson ... More

Intrinsic Chirality of Graphs in 3-manifoldsJun 12 2014Nov 17 2016The main result of this paper is that for every closed, connected, orientable, irreducible 3-manifold $M$, there is an integer $ n_M$ such that any abstract graph with no automorphism of order 2 which has a 3-connected minor whose genus is more than $n_M$ ... More

Antiderivatives and integral representations of associated Legendre functions with μ={\pm}νJan 16 2013We obtain antiderivatives and complex integral representations for associated Legendre functions and Ferrers functions (associated Legendre functions on-the-cut) of the first and second kind with degree and order equal to within a sign.

Fourier, Gegenbauer and Jacobi Expansions for a Power-Law Fundamental Solution of the Polyharmonic Equation and Polyspherical Addition TheoremsSep 26 2012Jun 05 2013We develop complex Jacobi, Gegenbauer and Chebyshev polynomial expansions for the kernels associated with power-law fundamental solutions of the polyharmonic equation on d-dimensional Euclidean space. From these series representations we derive Fourier ... More

Derivatives with respect to the degree and order of associated Legendre functions for $|z|>1$ using modified Bessel functionsNov 27 2009Expressions for the derivatives with respect to order of modified Bessel functions evaluated at integer orders and certain integral representations of associated Legendre functions with modulus argument greater than unity are used to compute derivatives ... More

The Maslov and Morse Indices for Sturm-Liouville Systems on the Half-LineMar 18 2019We show that for Sturm-Liouville Systems on the half-line $[0,\infty)$, the Morse index can be expressed in terms of the Maslov index and an additional term associated with the boundary conditions at $x = 0$. Relations are given both for the case in which ... More

Some Improvements on Deep Convolutional Neural Network Based Image ClassificationDec 19 2013We investigate multiple techniques to improve upon the current state of the art deep convolutional neural network based image classification pipeline. The techiques include adding more image transformations to training data, adding more transformations ... More

The Matrix Calculus You Need For Deep LearningFeb 05 2018Jul 02 2018This paper is an attempt to explain all the matrix calculus you need in order to understand the training of deep neural networks. We assume no math knowledge beyond what you learned in calculus 1, and provide links to help you refresh the necessary math ... More

William Pendry Bidelman (1918-2011)Sep 28 2016William P. Bidelman--Editor of Publications of the Astronomical Society of the Pacific from 1956 to 1961--passed away on 2011 May 3, at the age of 92. He was one of the last of the masters of visual stellar spectral classification and the identification ... More

Singular moduli refinedFeb 28 2012We prove a refinement of the results of Gross and Zagier on prime factorizations of singular moduli.

Tangent cones and regularity of real hypersurfacesMay 16 2010Sep 14 2013We characterize embedded $\C^1$ hypersurfaces of $\R^n$ as the only locally closed sets with continuously varying flat tangent cones whose measure-theoretic-multiplicity is at most $m<3/2$. It follows then that any (topological) hypersurface which has ... More

Multiplier ideals of monomial space curvesJun 09 2010Feb 22 2011The goal of this paper is to produce a formula for the multiplier ideals of monomial space curves in the spirit of Howald's formula for the multiplier ideals of monomial ideals. This is achieved by constructing a toric blowup of affine space in such a ... More

Normal curvatures of asymptotically constant graphs and Caratheodory's conjectureJan 15 2011Aug 26 2011We show that Caratheodory's conjecture, on umbilical points of closed convex surfaces, may be reformulated in terms of the existence of at least one umbilic in the graphs of functions f: R^2-->R whose gradient decays uniformly faster than 1/r. The divergence ... More

The geometry of the disk complexOct 15 2010We give a distance estimate for the metric on the disk complex and show that it is Gromov hyperbolic. As another application of our techniques, we find an algorithm which computes the Hempel distance of a Heegaard splitting, up to an error depending only ... More

The set of non-uniquely ergodic d-IETs has Hausdorff codimension 1/2Jan 02 2018We show that the set of not uniquely ergodic d-IETs has Hausdorff dimension d-3/2 (in the (d-1)-dimension space of d-IETs) for d>4. For d=4 this was shown by Athreya-Chaika and for d=2,3 the set is known to have dimension d-2.

A Gross-Kohnen-Zagier formula for Heegner-Drinfeld cyclesJul 01 2017May 06 2019Let $F$ be the field of rational functions on a smooth projective curve over a finite field, and let $\pi$ be an unramified cuspidal automorphic representation for $\mathrm{PGL}_2$ over $F$. We prove a variant of the formula of Yun and Zhang relating ... More

Moderate interaction between 3d- and 4f-electrons and ferrimagnetism in Co-doped GdFeAsODec 02 2012We synthesized a series of GdFe$_{1-x}$Co$_x$AsO polycrystalline samples ($0 \leq x \leq 1$) by using a solid state reaction method and present a systematic study on the physical properties by means of electrical resistivity $\rho(T)$, magnetic susceptibility ... More

Radio Planetary Nebulae in the Small Magellanic CloudFeb 11 2016We present ten new radio continuum (RC) detections at catalogued planetary nebula (PN) positions in the Small Magellanic Cloud (SMC): SMPS6, LIN 41, LIN 142, SMP S13, SMP S14, SMP S16, J18, SMP S18, SMP S19 and SMP S22. Additionally, six SMC radio PNe ... More

Stochastic Galerkin methods for the steady-state Navier-Stokes equationsJun 29 2015Apr 14 2016We study the steady-state Navier-Stokes equations in the context of stochastic finite element discretizations. Specifically, we assume that the viscosity is a random field given in the form of a generalized polynomial chaos expansion. For the resulting ... More

Three regimes of extrasolar planets inferred from host star metallicitiesMay 29 2014Approximately half of the extrasolar planets (exoplanets) with radii less than four Earth radii are in orbits with short periods. Despite their sheer abundance, the compositions of such planets are largely unknown. The available evidence suggests that ... More

Two Exoplanets Discovered at Keck ObservatoryAug 12 2009We present two exoplanets detected at Keck Observatory. HD 179079 is a G5 subgiant that hosts a hot Neptune planet with Msini = 27.5 M_earth in a 14.48 d, low-eccentricity orbit. The stellar reflex velocity induced by this planet has a semiamplitude of ... More

Friends of Hot Jupiters II: No Correspondence Between Hot-Jupiter Spin-Orbit Misalignment and the Incidence of Directly Imaged Stellar CompanionsDec 30 2014Jan 13 2015Multi-star systems are common, yet little is known about a stellar companion's influence on the formation and evolution of planetary systems. For instance, stellar companions may have facilitated the inward migration of hot Jupiters towards to their present ... More

Merger Signatures in the Dynamics of Star-forming GasNov 26 2015Spatially resolved kinematics have been used to determine the dynamical status of star-forming galaxies with ambiguous morphologies, and constrain the importance of galaxy interactions during the assembly of galaxies. However, measuring the importance ... More

Avalanches on a conical bead pile: scaling with tuning parametersJan 02 2012Feb 24 2012Uniform spherical beads were used to explore the behavior of a granular system near its critical angle of repose on a conical bead pile. We found two tuning parameters that could take the system to a critical point where a simple power-law described the ... More

Inelastic X-ray Scattering Study of Phonons in Superconducting CaC6Sep 08 2007Oct 30 2007We investigate the dispersion and temperature dependence of a number of phonons in the recently discovered superconductor CaC6 utilizing inelastic x-ray scattering. Four [00L] and two ab-plane phonon modes are observed, and measured at temperatures both ... More

Kinematic classifications of local interacting galaxies: implications for the merger/disk classifications at high-zMar 17 2015The classification of galaxy mergers and isolated disks is key for understanding the relative importance of galaxy interactions and secular evolution during the assembly of galaxies. The kinematic properties of galaxies as traced by emission lines have ... More

Model Data Fusion: developing Bayesian inversion to constrain equilibrium and mode structureFeb 17 2010Recently, a new probabilistic "data fusion" framework based on Bayesian principles has been developed on JET and W7-AS. The Bayesian analysis framework folds in uncertainties and inter-dependencies in the diagnostic data and signal forward-models, together ... More

Configurational Effects on Alfvenic modes and Confinement in the H-1NF HeliacFeb 27 2009The flexible Heliac coil set of helical axis stellarator H-1 (R=1m, <r>~0.15-0.2 m) permits access to a wide range of magnetic configurations. Surprisingly, in the absence of any obvious population of energetic particles, Alfven modes normally associated ... More

Connecting electron and phonon spectroscopy data to consistently determine quasiparticle-phonon coupling on the surface of topological insulatorsOct 18 2013Oct 21 2013Photoemission and phonon spectroscopies have yielded widely varying estimates of the electron-phonon coupling constant \lambda\ on the surfaces of topological insulators, even for a particular material and technique. We connect the results of these experiments ... More

Periodic Variability of the Barium Central Star of the Planetary Nebula Abell 70Aug 03 2018Abell 70 is a planetary nebula (PN) whose nucleus at optical wavelengths is a G8 star with enhanced carbon and s-process abundances--a "barium star." The cool star is a binary companion of the true, hot central star. In several other members of this rare ... More

Quantifying Teaching Behaviour in Robot Learning from DemonstrationMay 10 2019Learning from demonstration allows for rapid deployment of robot manipulators to a great many tasks, by relying on a person showing the robot what to do rather than programming it. While this approach provides many opportunities, measuring, evaluating ... More

Numerical Solution of the Steady-State Navier-Stokes Equations using Empirical Interpolation MethodsMay 19 2016Reduced-order modeling is an efficient approach for solving parameterized discrete partial differential equations when the solution is needed at many parameter values. An offline step approximates the solution space and an online step utilizes this approximation, ... More