Results for "Rebecca Boll"

total 968took 0.11s
On multidimensional consistent systems of asymmetric quad-equationsJan 05 2012Multidimensional Consistency becomes more and more important in the theory of discrete integrable systems. Recently, we gave a classification of all 3D consistent 6-tuples of equations with the tetrahedron property, where several novel asymmetric systems ... More
Classification of 3D consistent quad-equationsSep 21 2010Nov 03 2010We consider 3D consistent systems of six independent quad-equations assigned to the faces of a cube. The well-known classification of 3D consistent quad-equations, the so-called ABS-list, is included in this situation. The extension of these equations ... More
On the Lagrangian structure of 3D consistent systems of asymmetric quad-equationsJul 29 2011Recently, the first-named author gave a classification of 3D consistent 6-tuples of quad-equations with the tetrahedron property; several novel asymmetric 6-tuples have been found. Due to 3D consistency, these 6-tuples can be extended to discrete integrable ... More
Non-symmetric discrete Toda systems from quad-graphsAug 19 2009For all non-symmetric discrete relativistic Toda type equations we establish a relation to 3D consistent systems of quad-equations. Unlike the more simple and better understood symmetric case, here the three coordinate planes of $\mathbb Z^3$ carry different ... More
Multi-time Lagrangian 1-forms for families of Bäcklund transformations. Toda-type systemsFeb 28 2013General Lagrangian theory of discrete one-dimensional integrable systems is illustrated by a detailed study of B\"acklund transformations for Toda-type systems. Commutativity of B\"acklund transformations is shown to be equivalent to consistency of the ... More
Atoms ionized by assisted attopulses behaving as diatomic moleculesDec 18 2015The single ionization of noble gas atoms by the combined action of XUV attopulses and an infrared laser field is theoretically investigated by means of a non-perturbative model that under certain approximations gives closed-form expressions for the angular ... More
Comparing algorithms for sorting with t stacks in seriesApr 08 2004Jun 18 2004We show that the left-greedy algorithm is a better algorithm than the right-greedy algorithm for sorting permutations using t stacks in series when t>1. We also supply a method for constructing some permutations that can be sorted by t stacks in series ... More
Brill-Noether-type Theorems with a Movable Ramification PointApr 29 2008The classical Brill-Noether theorems count the dimension of the family of maps from a general curve of genus g to non-degenerate curves of degree d in r-dimensional projective space. These theorems can be extended to include ramification conditions at ... More
The Adjoints of the Schur FunctorJan 14 2016Jan 20 2016We show that the left and right adjoint of the Schur functor can be expressed in terms of the monoidal structure of strict polynomial functors. Using this result we give a necessary and sufficient condition for when the tensor product of two simple strict ... More
Partizan Kayles and Misere InvertibilitySep 06 2013The impartial combinatorial game Kayles is played on a row of pins, with players taking turns removing either a single pin or two adjacent pins. A natural partizan variation is to allow one player to remove only a single pin and the other only a pair ... More
An Empirical Evaluation of Probabilistic Lexicalized Tree Insertion GrammarsAug 04 1998We present an empirical study of the applicability of Probabilistic Lexicalized Tree Insertion Grammars (PLTIG), a lexicalized counterpart to Probabilistic Context-Free Grammars (PCFG), to problems in stochastic natural-language processing. Comparing ... More
Cohomological invariants of groups of order p^3Feb 20 2015We show that the nonabelian groups of order p^3 for odd prime p have no nontrivial cohomological invariants of degree 3.
Twists and TwistabilityFeb 01 2018Metrically homogeneous graphs are connected graphs which, when endowed with the path metric, are homogeneous as metric spaces. In this paper we introduce the concept of twisted automorphisms, a notion of isomorphism up to a permutation of the language. ... More
The genus of projective curves on complete intersection surfacesAug 15 2014Sep 03 2014We bound the genus of a projective curve lying on a complete intersection surface in terms of its degree and the degrees of the defining equations of the surface on which it lies.
On Bianchi permutability of Bäcklund transformations for asymmetric quad-equationsNov 19 2012May 29 2013We prove the Bianchi permutability (existence of superposition principle) of B\"acklund transformations for asymmetric quad-equations. Such equations and there B\"acklund transformations form 3D consistent systems of a priori different equations. We perform ... More
Two-dimensional variational systems on the root lattice $Q(A_{N})$Jan 20 2016We study certain two-dimensional variational systems, namely pluri-Lagrangian systems on the root lattice $Q(A_{N})$. Here, we follow the scheme which was already used to define two-dimensional pluri-Lagrangian systems on the lattice $\mathbb{Z}^{N}$ ... More
A Decreasing Stack and an Increasing Stack in SeriesJan 28 2013We study a sorting machine consisting of two stacks in series where the first stack has the added restriction such that entries in the stack must be in decreasing order from top to bottom. We give the basis of the class of permutations that are sortable ... More
Computing Higher Indicators for the Double of a Symmetric GroupJun 28 2012In this paper we explicitly determine all indicators for the Drinfel'd doubles of the symmetric group acting upon up to 10 objects. We explore when distinct characters give exactly the same indicators and when the indicators have a zero value. We find ... More
Generalized Yang-Baxter Equations and Braiding Quantum GatesAug 26 2011Solutions to the Yang-Baxter equation - an important equation in mathematics and physics - and their afforded braid group representations have applications in fields such as knot theory, statistical mechanics, and, most recently, quantum information science. ... More
Time-resolved inner-shell photoelectron spectroscopy: from a bound molecule to an isolated atomJan 25 2019Due to its element- and site-specificity, inner-shell photoelectron spectroscopy is a widely used technique to probe the chemical structure of matter. Here we show that time-resolved inner-shell photoelectron spectroscopy can be employed to observe ultrafast ... More
Online Data Thinning via Multi-Subspace TrackingSep 12 2016In an era of ubiquitous large-scale streaming data, the availability of data far exceeds the capacity of expert human analysts. In many settings, such data is either discarded or stored unprocessed in datacenters. This paper proposes a method of online ... More
Symmetry, Isotopy, and Irregular CoversSep 14 2013We say that a cover of surfaces S -> X has the Birman--Hilden property if the subgroup of the mapping class group of X consisting of mapping classes that have representatives that lift to S embeds in the mapping class group of S modulo the group of deck ... More
Regularized Non-Gaussian Image DenoisingAug 12 2015In image denoising problems, one widely-adopted approach is to minimize a regularized data-fit objective function, where the data-fit term is derived from a physical image acquisition model. Typically the regularizer is selected with two goals in mind: ... More
A stack and a pop stack in seriesMar 06 2013We study sorting machines consisting of a stack and a pop stack in series, with or without a queue between them. While there are, a priori, four such machines, only two are essentially different: a pop stack followed directly by a stack, and a pop stack ... More
Dual Filtered GraphsOct 28 2014May 02 2016We define a K-theoretic analogue of Fomin's dual graded graphs, which we call dual filtered graphs. The key formula in the definition is DU-UD= D + I. Our major examples are K-theoretic analogues of Young's lattice, of shifted Young's lattice, and of ... More
Graphs with no 7-wheel subdivisionNov 04 2013Dec 17 2013The subgraph homeomorphism problem, SHP($H$), has been shown to be polynomial-time solvable for any fixed pattern graph $H$, but practical algorithms have been developed only for a few specific pattern graphs. Among these are the wheels with four, five, ... More
Closure operations that induce big Cohen-Macaulay algebrasDec 24 2015May 22 2017We study closure operations over a local domain R that satisfy a set of axioms introduced by Geoffrey Dietz. The existence of a closure operation satisfying the axioms (called a Dietz closure) is equivalent to the existence of a big Cohen-Macaulay module ... More
Lagrangian-type submanifolds of Spin(7) manifolds and their deformationsJan 27 2016In an earlier paper we showed that the space of deformations of a smooth, compact, orientable Harvey-Lawson submanifold HL in a G2 manifold M can be identified with the direct sum of the space of smooth functions and closed 2-forms on HL. In that paper, ... More
K-theoretic Poirier-Reutenauer bialgebraApr 16 2014We use the K-Knuth equivalence of Buch and Samuel to define a K-theoretic analogue of the Poirier-Reutenauer Hopf algebra. As an application, we rederive the K-theoretic Littlewood-Richardson rules of Thomas and Yong and of Buch and Samuel.
Cross-Newell equations for hexagons and trianglesOct 16 1999The Cross-Newell equations for hexagons and triangles are derived for general real gradient systems, and are found to be in flux-divergence form. Specific examples of complex governing equations that give rise to hexagons and triangles and which have ... More
Lattice Designs in Standard and Simple Implicit Multi-linear RegressionMar 25 2016Statisticians generally use ordinary least squares to minimize the random error in a subject response with respect to independent explanatory variable. However, Wooten shows illustrates how ordinary least squares can be used to minimize the random error ... More
Wach modules, regulator maps, and epsilon-isomorphisms in familiesOct 31 2016We prove the local epsilon-isomorphism conjecture of Fukaya and Kato [FK06] for certain crystalline families of G_Qp-representations. This conjecture can be regarded as a local analogue of the Iwasawa main conjecture for families. Our work extends earlier ... More
Search strategies for developing characterizations of graphs without small wheel subdivisionsNov 04 2013Practical algorithms for solving the Subgraph Homeomorphism Problem are known for only a few small pattern graphs: among these are the wheel graphs with four, five, six, and seven spokes. The length and difficulty of the proofs leading to these algorithms ... More
Load Balancing in Mobility-on-Demand Systems: Reallocation Via Parametric Control Using Concurrent EstimationApr 07 2019Mobility-on-Demand (MoD) systems require load balancing to maintain consistent service across regions with uneven demand subject to time-varying traffic conditions. The load-balancing objective is to jointly minimize the fraction of lost customer requests ... More
Targeted Syntactic Evaluation of Language ModelsAug 27 2018We present a dataset for evaluating the grammaticality of the predictions of a language model. We automatically construct a large number of minimally different pairs of English sentences, each consisting of a grammatical and an ungrammatical sentence. ... More
Emergent Ising degrees of freedom above double-stripe magnetismAug 14 2017Aug 22 2017Double-stripe magnetism $[\mathbf{Q}=(\pi/2, \pi/2)]$ has been proposed as the magnetic ground state for both the iron-telluride and BaTi$_2$Sb$_2$O families of superconductors. Double-stripe order is captured within a $J_1-J_2-J_3$ Heisenberg model in ... More
Pattern avoidance in permutations and their squaresDec 31 2018We study permutations $p$ so that both $p$ and $p^2$ avoid a given pattern $q$.
Generalized twistor spaces for hyperkähler manifoldsSep 18 2013Let M be a hyperk\"ahler manifold. The S^2-family of complex structures compatible with the hyperk\"ahler metric can be assembled into a single complex structure on Z=MxS^2; the resulting complex manifold is known as the twistor space of M. We describe ... More
An Improved Deterministic Rescaling for Linear Programming AlgorithmsDec 14 2016The perceptron algorithm for linear programming, arising from machine learning, has been around since the 1950s. While not a polynomial-time algorithm, it is useful in practice due to its simplicity and robustness. In 2004, Dunagan and Vempala showed ... More
Weighted hyperprojective spaces and homotopy invariance in orbifold cohomologyAug 16 2007We show that Chen-Ruan cohomology is a homotopy invariant in certain cases. We introduce the notion of a T-representation homotopy, which is a stringent form of homotopy under which Chen-Ruan cohomology is invariant. We show that while hyperkahler quotients ... More
Chiral RKKY interaction in Pr2Ir2O7Jan 04 2013Motivated by the potential chiral spin liquid in the metallic spin ice Pr2Ir2O7, we consider how such a chiral state might be selected from the spin ice manifold. We propose that chiral fluctuations of the conducting Ir moments promote ferro-chiral couplings ... More
Tandem Pairing in Heavy Fermion SuperconductorsDec 11 2009May 07 2010We examine the internal structure of the heavy fermion condensate, showing that it necessarily involves a d-wave pair of quasiparticles on neighboring lattice sites, condensed in tandem with a composite pair of electrons bound to a local moment, within ... More
Six Challenges for Neural Machine TranslationJun 12 2017We explore six challenges for neural machine translation: domain mismatch, amount of training data, rare words, long sentences, word alignment, and beam search. We show both deficiencies and improvements over the quality of phrase-based statistical machine ... More
The concept of "character" in Dirichlet's theorem on primes in an arithmetic progressionSep 17 2012Jun 26 2013In 1837, Dirichlet proved that there are infinitely many primes in any arithmetic progression in which the terms do not all share a common factor. We survey implicit and explicit uses of Dirichlet characters in presentations of Dirichlet's proof in the ... More
Missing Data in Sparse Transition Matrix Estimation for Sub-Gaussian Vector Autoregressive ProcessesFeb 26 2018High-dimensional time series data exist in numerous areas such as finance, genomics, healthcare, and neuroscience. An unavoidable aspect of all such datasets is missing data, and dealing with this issue has been an important focus in statistics, control, ... More
The Chow ring of the classifying space $BSO(2n,{\mathbb C})$Nov 19 2004We compute the Chow ring of the classifying space $BSO(2n,\C)$ in the sense of Totaro using the fibration $Gl(2n)/SO(2n) \to BSO(2n) \to BGl(2n)$ and a computation of the Chow ring of $Gl(2n)/SO(2n)$ in a previous paper. We find this Chow ring is generated ... More
Two-stack-sorting with pop stacksJan 15 2018Feb 01 2019We consider the set of permutations that are sorted after two passes through a pop stack. We characterize these permutations in terms of forbidden patterns (classical and barred) and enumerate them according to the ascent statistic. Then we show these ... More
Characterization of precipitation in Al-Li alloy AA2195 by means of atom probe tomography and transmission electron microscopyDec 11 2014The microstructure of the commercial alloy AA2195 was investigated on the nano-scale after conducting a T8 tempering. This particular thermo-mechanical treatment of the specimen resulted in the formation of platelet-shaped $T_{1}$ ($Al_{2}CuLi$)/ $\theta^{'}$($Al_{2}Cu$) ... More
Flavor-dependent azimuthal modulations in unpolarized SIDIS cross section at HERMESNov 24 2010The $\cos\phi_h$ and $\cos2\phi_h$ azimuthal modulations of the unpolarized hadron Semi-Inclusive Deep Inelastic Scattering cross section are sensitive to the quark intrinsic transverse momentum and transverse spin. These modulations have been measured ... More
Integrating Gricean and Attentional ConstraintsMay 19 1995This paper concerns how to generate and understand discourse anaphoric noun phrases. I present the results of an analysis of all discourse anaphoric noun phrases (N=1,233) in a corpus of ten narrative monologues, where the choice between a definite pronoun ... More
Introduction to Implicit RegressionJan 30 2016Statisticians usually restrict regression to model relationships that are explicitly defined dependent and independent random variables; this paper outlines the newly developed method of non-response analysis and rotational analysis for evaluating co-dependent ... More
A 500 kpc HI Tail of the Virgo Pair NGC4532/DDO137 Detected by ALFALFAJul 22 2007HI observations of the Virgo Cluster pair NGC 4532/DDO 137, conducted as part of the Arecibo Legacy Fast ALFA Survey (ALFALFA), reveal an HI feature extending ~500 kpc to the southwest. The structure has a total mass of up to 7 x 10^8 solar masses, equivalent ... More
Dynamics of Black Hole Pairs II: Spherical Orbits and the Homoclinic Limit of Zoom-WhirlinessNov 24 2008Spinning black hole pairs exhibit a range of complicated dynamical behaviors. An interest in eccentric and zoom-whirl orbits has ironically inspired the focus of this paper: the constant radius orbits. When black hole spins are misaligned, the constant ... More
A survey of partizan misere game theoryJun 23 2016Much progress has been made in misere game theory using the technique of restricted misere play, where games can be considered equivalent inside a restricted set of games without being equal in general. This paper provides a survey of recent results in ... More
Principal Component Analysis: Resources for an Essential Application of Linear AlgebraApr 15 2016Principal Component Analysis (PCA) is a highly useful topic within an introductory Linear Algebra course, especially since it can be used to incorporate a number of applied projects. This method represents an essential application and extension of the ... More
Analytic PSF Correction for Gravitational Flexion StudiesAug 28 2013May 23 2014Given a galaxy image, one cannot simply measure its flexion. An image's spin one and three shape properties, typically associated with F- and G-flexion, are actually complicated functions of the galaxy's intrinsic shape and the telescope's PSF, in addition ... More
Distinguishing Word Senses in Untagged TextJun 09 1997This paper describes an experimental comparison of three unsupervised learning algorithms that distinguish the sense of an ambiguous word in untagged text. The methods described in this paper, McQuitty's similarity analysis, Ward's minimum-variance method, ... More
Word-Sense Disambiguation Using Decomposable ModelsJun 01 1994Most probabilistic classifiers used for word-sense disambiguation have either been based on only one contextual feature or have used a model that is simply assumed to characterize the interdependencies among multiple contextual features. In this paper, ... More
Orbifold cohomology of hypertoric varietiesJul 18 2006Oct 14 2007Hypertoric varieties are hyperk\"ahler analogues of toric varieties, and are constructed as abelian hyperk\"ahler quotients of a quaternionic affine space. Just as symplectic toric orbifolds are determined by labelled polytopes, orbifold hypertoric varieties ... More
Deformations of Lagrangian Type Submanifolds inside G2 manifoldsMar 10 20153-dimensional Harvey Lawson submanifolds were introduced in an earlier paper by Akbulut-Salur, as examples of Lagrangian-type manifolds inside G2 manifold. In this paper, we first show that the space of deformations of a smooth, compact, orientable Harvey-Lawson ... More
An Involution on Involutions and a Generalization of Layered PermutationsMay 19 2016Apr 03 2019Taking transposes of Standard Young Tableaux defines a natural involution on the set $I(n)$ of involutions of length $n$ via the the Robinson-Schensted correspondence. In some cases, this involution can be defined without resorting to the Robinson-Schensted ... More
Greene--Kleitman invariants for Sulzgruber insertionAug 31 2017R. Sulzgruber's rim hook insertion and the Hillman-Grassl correspondence are two distinct bijections between the reverse plane partitions of a fixed partition shape and multisets of rim-hooks of the same partition shape. It is known that Hillman-Grassl ... More
Transitive permutation groups with trivial four point stabilizersNov 27 2014In this paper we analyze the structure of transitive permutation groups that have trivial four point stabilizers, but some nontrivial three point stabilizer. In particular we give a complete, detailed classification when the group is simple or quasisimple. ... More
Survival of a recessive allele in a Mendelian diploid modelMay 08 2015Aug 23 2016In this paper we analyse the genetic evolution of a diploid hermaphroditic population, which is modelled by a three-type nonlinear birth-and-death process with competition and Mendelian reproduction. In a recent paper, Collet et al., 2013 have shown that, ... More
Closure operations that induce big Cohen-Macaulay modules and classification of singularitiesDec 18 2015Jul 01 2016Geoffrey Dietz introduced a set of axioms for a closure operation on a complete local domain R so that the existence of such a closure operation is equivalent to the existence of a big Cohen-Macaulay module. These closure operations are called Dietz closures. ... More
Measuring, Understanding, and Classifying News Media Sympathy on Twitter after Crisis EventsJan 16 2018Mar 15 2018This paper investigates bias in coverage between Western and Arab media on Twitter after the November 2015 Beirut and Paris terror attacks. Using two Twitter datasets covering each attack, we investigate how Western and Arab media differed in coverage ... More
Applying Reliability Metrics to Co-Reference AnnotationJun 10 1997Studies of the contextual and linguistic factors that constrain discourse phenomena such as reference are coming to depend increasingly on annotated language corpora. In preparing the corpora, it is important to evaluate the reliability of the annotation, ... More
The symplectic-N t-J model and s$_\pm$ superconductorsApr 10 2012Apr 24 2012The possible discovery of $s_\pm$ superconducting gaps in the moderately correlated iron-based superconductors has raised the question of how to properly treat $s_\pm$ gaps in strongly correlated superconductors. Unlike the d-wave cuprates, the Coulomb ... More
Spins, electrons and broken symmetries: realizations of two channel Kondo physicsAug 11 2014Adding a second Kondo channel to heavy fermion materials reveals new exotic symmetry breaking phases associated with the development of Kondo coherence. In this paper, we review two such phases, the "hastatic order" associated with non-Kramers doublet ... More
Symplectic N and time reversal in frustrated magnetismOct 28 2008Nov 19 2008Identifying the time reversal symmetry of spins as a symplectic symmetry, we develop a large N approximation for quantum magnetism that embraces both antiferromagnetism and ferromagnetism. In SU(N), N>2, not all spins invert under time reversal, so we ... More
Virgo Early-Type Dwarfs in ALFALFAJul 22 2007Early-type dwarf galaxies dominate cluster populations, but their formation and evolutionary histories are poorly understood. The ALFALFA (Arecibo Legacy Fast ALFA) survey has completed observations of the Virgo Cluster in the declination range of 6 - ... More
Closure operations that induce big Cohen-Macaulay algebrasDec 24 2015We study closure operations over a local domain R that satisfy a set of axioms introduced by Geoffrey Dietz. The existence of a closure operation satisfying the axioms (called a Dietz closure) is equivalent to the existence of a big Cohen-Macaulay module ... More
Neutrino capture by r-process waiting-point nucleiMay 04 1998We use the Quasiparticle Random Phase Approximation to include the effects of low-lying Gamow-Teller and first forbidden strength in neutrino capture by very neutron-rich nuclei with N = 50, 82, or 126. For electron neutrinos in what is currently considered ... More
Measurement of azimuthal asymmetries of the unpolarized cross section at HERMESJan 16 2009A multi-dimensional (x, y, z, P_{h\perp}) extraction of cos\phi_h and cos2\phi_h azimuthal asymmetries of unpolarized Semi-Inclusive Deep Inelastic Scattering at HERMES is discussed. The use of data taken with hydrogen and deuterium targets and the separation ... More
Topological containment of the 5-clique minus an edge in 4-connected graphsMay 03 2017May 04 2017The topological containment problem is known to be polynomial-time solvable for any fixed pattern graph $H$, but good characterisations have been found for only a handful of non-trivial pattern graphs. The complete graph on five vertices, $K_5$, is one ... More
The Machine Learning Algorithm as Creative Musical ToolNov 01 2016Machine learning is the capacity of a computational system to learn structures from datasets in order to make predictions on newly seen data. Such an approach offers a significant advantage in music scenarios in which musicians can teach the system to ... More
An Involution on Involutions and a Generalization of Layered PermutationsMay 19 2016Taking transposes of Standard Young Tableaux defines a natural involution on the set $I(n)$ of involutions of length $n$ via the the Robinson-Schensted correspondence. In some cases, this involution can be defined without resorting to the Robinson-Schensted ... More
Character and objectApr 18 2014Dec 21 2015In 1837, Dirichlet proved that there are infinitely many primes in any arithmetic progression in which the terms do not all share a common factor. Modern presentations of the proof are explicitly higher-order, in that they involve quantifying over and ... More
Restricted developments in partizan misere game theoryJun 23 2016Jan 30 2019Much progress has been made in misere game theory using the technique of restricted misere play, where games can be considered equivalent inside a restricted set of games without being equal in general. This paper provides a survey of recent results in ... More
Programmable Control of Nucleation for Algorithmic Self-AssemblyJul 13 2006Jan 08 2010Algorithmic self-assembly, a generalization of crystal growth processes, has been proposed as a mechanism for autonomous DNA computation and for bottom-up fabrication of complex nanostructures. A `program' for growing a desired structure consists of a ... More
Lifting of Characters for Nonlinear Simply Laced GroupsSep 05 2008One aspect of the Langlands program for linear groups is lifting of characters, which relates virtual representations on a group $G$ with those on an endoscopic group for $G$. The goal of this paper is to extend this theory to nonlinear two-fold covers ... More
The Chow ring of the symmetric space Gl(2n,C)/SO(2n,C)Mar 22 2001We show this Chow ring is $\Z \oplus \Z$. We do this by partitioning the space into 2n subvarieties each of which is fibered over $Gl(2n-2,\C)/SO(2n-2,\C)$.
Bridgeland stability conditions on surfaces with curves of negative self-intersectionFeb 21 2017Aug 27 2018Let $X$ be a smooth complex projective variety. In 2002, Bridgeland defined a notion of stability for the objects in $D^b(X)$, the bounded derived category of coherent sheaves on $X$, which generalized the notion of slope stability for vector bundles ... More
Photophysics of indole upon x-ray absorptionFeb 08 2018A photofragmentation study of gas-phase indole (C$_8$H$_7$N) upon single-photon ionization at a photon energy of 420 eV is presented. Indole was primarily inner-shell ionized at its nitrogen and carbon $1s$ orbitals. Electrons and ions were measured in ... More
Photophysics of indole upon x-ray absorptionFeb 08 2018Jul 19 2018A photofragmentation study of gas-phase indole (C$_8$H$_7$N) upon single-photon ionization at a photon energy of 420 eV is presented. Indole was primarily inner-shell ionized at its nitrogen and carbon $1s$ orbitals. Electrons and ions were measured in ... More
Increasing the output of a Littman-type laser by use of an intracavity Faraday rotatorSep 30 2005We present a new method of external-cavity diode laser grating stabilization which combines the high output power of the Littrow design with the fixed output pointing of the Littman-Metcalf design. Our new approach utilizes a Faraday-effect optical isolator ... More
Performance bounds on compressed sensing with Poisson noiseJan 13 2009Apr 30 2009This paper describes performance bounds for compressed sensing in the presence of Poisson noise when the underlying signal, a vector of Poisson intensities, is sparse or compressible (admits a sparse approximation). The signal-independent and bounded ... More
On the formation and evolution of asteroid belts and their potential significance for lifeOct 31 2012Suggestions have been made that asteroid belts may be important both for the existence of life and perhaps even for the evolution of complex life on a planet. Using numerical models for protoplanetary discs we calculate the location of the snow line, ... More
Ω_0 from the Apparent Evolution of Gas Fractions in Rich Clusters of GalaxiesMar 06 1998We apply a unique gas fraction estimator to published X-ray cluster properties and we compare the derived gas fractions of observed clusters to simulated ones. The observations are consistent with a universal gas fraction of 0.15+/-0.01h_{50}^{-3/2} for ... More
Philipp Reis's telephone in AberdeenNov 04 2018A telephone sender following the design of Johann Philipp Reis made by W Ladd, London 1863, in the Natural Philosophy Collection of the University of Aberdeen is illustrated and described. How Reis came to invent a telephone some 15 years before Graham ... More
Minimally-corrected partial atomic charges for non-covalent electrostatic interactionsFeb 21 2017May 01 2017We develop a new scheme for determining molecular partial atomic charges (PACs) with external electrostatic potential (ESP) closely mimicking that of the molecule. The PACs are the "minimal corrections" to a reference-set of PACs necessary for reproducing ... More
OmniGraph: Rich Representation and Graph Kernel LearningOct 10 2015OmniGraph, a novel representation to support a range of NLP classification tasks, integrates lexical items, syntactic dependencies and frame semantic parses into graphs. Feature engineering is folded into the learning through convolution graph kernel ... More
The TeV Blazar Measurement of the Extragalactic Background LightOct 02 2013Dec 05 2013Gamma-rays propagating through space are likely to be extinguished via electron-positron pair production off of the ambient extragalactic background light (EBL). The spectrum of the EBL is produced by starlight (and starlight reprocessed by dust) from ... More
The Birman-Hilden theoryMar 09 2017In the 1970s Joan Birman and Hugh Hilden wrote several papers on the problem of relating the mapping class group of a surface to that of a cover. We survey their work, give an overview of the subsequent developments, and discuss open questions and new ... More
On the Evolution of the Snow Line in Protoplanetary DiscsJul 18 2012We model the evolution of the snow line in a protoplanetary disc. If the magneto-rotational instability (MRI) drives turbulence throughout the disc, there is a unique snow line outside of which the disc is icy. The snow line moves closer to the star as ... More
On the evolution of the snow line in protoplanetary discs II: Analytic approximationsJun 21 2013We examine the evolution of the snow line in a protoplanetary disc that contains a dead zone (a region of zero or low turbulence). The snow line is within a self-gravitating part of the dead zone, and we obtain a fully analytic solution for its radius. ... More
Enhancing laser sideband cooling in one-dimensional optical lattices via the dipole interactionJan 14 2010We study resolved sideband laser cooling of a one-dimensional optical lattice with one atom per site, and in particular the effect of the dipole interaction between radiating atoms. For simplicity, we consider the case where only a single cooling laser ... More
Generalized estimators for multiple testing: proportion of true nulls and false discovery rateOct 16 2014Two new estimators are proposed: the first for the proportion of true null hypotheses and the second for the false discovery rate (FDR) of one-step multiple testing procedures (MTPs). They generalize similar estimators developed jointly by Storey, Taylor ... More
Sparse Linear Regression With Missing DataMar 28 2015This paper proposes a fast and accurate method for sparse regression in the presence of missing data. The underlying statistical model encapsulates the low-dimensional structure of the incomplete data matrix and the sparsity of the regression coefficients, ... More
Probabilistic Blocking with An Application to the Syrian ConflictOct 11 2018Entity resolution seeks to merge databases as to remove duplicate entries where unique identifiers are typically unknown. We review modern blocking approaches for entity resolution, focusing on those based upon locality sensitive hashing (LSH). First, ... More