Results for "Ian A. Bond"

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Detecting Extra-Solar Planets via Microlensing at High MagnificationSep 09 2002Extra-solar planets can be efficiently detected in gravitational microlensing events of high magnification. High accuracy photometry is required over a short, well-defined time interval only, of order 10-30 hours. Most planets orbiting the lens star are ... More
Clues to the Metallicity Distribution in the Galactic Bulge: Abundances in MOA-2008-BLG310 and MOA-2008-BLG311Apr 13 2009May 08 2009We present abundance analyses based on high dispersion and high signal-to-noise ratio Magellan spectra of two highly microlensed Galactic bulge stars in the region of the main sequence turnoff with Teff ~ 5650 K. We find that MOA-2008-BLG310 has [Fe/H]= ... More
A Second Method to Photometrically Align Multi-Site Microlensing Light Curves: Source Color in Planetary Event MOA-2007-BLG-192Oct 12 2009At present, microlensing light curves from different telescopes and filters are photometrically aligned by fitting them to a common model. We present a second method based on photometry of common field stars. If two spectral responses are similar (or ... More
Identification of the OGLE-2003-BLG-235/MOA-2003-BLG-53 Planetary Host StarJun 02 2006Aug 03 2006We present the results of HST observations of the host star for the first definitive extrasolar planet detected by microlensing. The light curve model for this event predicts that the lens star should be separated from the source star by ~6mas at the ... More
The Demographics of Extrasolar Planets Beyond the Snow Line with Ground-based Microlensing SurveysMar 04 2009In the currently-favored paradigm of planet formation, the location of the snow line in the protoplanetary disk plays a crucial role. Determining the demographics of planets beyond the snow line of stars of various masses is thus essential for testing ... More
Better-than-expert detection of early coronary artery occlusion from 12 lead electrocardiograms using deep learningMar 11 2019Early diagnosis of acute coronary artery occlusion based on electrocardiogram (ECG) findings is essential for prompt delivery of primary percutaneous coronary intervention. Current ST elevation (STE) criteria are specific but insensitive. Consequently, ... More
Augmenting expert detection of early coronary artery occlusion from 12 lead electrocardiograms using deep learningMar 11 2019Mar 20 2019Early diagnosis of acute coronary artery occlusion based on electrocardiogram (ECG) findings is essential for prompt delivery of primary percutaneous coronary intervention. Current ST elevation (STE) criteria are specific but insensitive. Consequently, ... More
Better-than-expert detection of early coronary artery occlusion from 12 lead electrocardiograms using deep learningMar 11 2019Mar 13 2019Early diagnosis of acute coronary artery occlusion based on electrocardiogram (ECG) findings is essential for prompt delivery of primary percutaneous coronary intervention. Current ST elevation (STE) criteria are specific but insensitive. Consequently, ... More
Astrophysical Implications of a New Dynamical Mass for the Nearby White Dwarf 40 Eridani BSep 01 2017The bright, nearby DA-type white dwarf (WD) 40 Eridani B is orbited by the M dwarf 40 Eri C, allowing determination of the WD's mass. Until recently, however, the mass depended on orbital elements determined four decades ago, and that mass was so low ... More
Microlensing Results Challenge the Core Accretion Runaway Growth Scenario for Gas GiantsDec 31 2018We compare the planet-to-star mass-ratio distribution measured by gravitational microlensing to core accretion theory predictions from population synthesis models. The core accretion theory's runaway gas accretion process predicts a dearth of intermediate-mass ... More
Direct Extragalactic Distance Determination Using X-Ray ScatteringJul 20 2004We examine the feasibility of using dust-scattered X-rays for direct determination of distances to nearby galaxies with bright background AGNs, QSOs, or GRBs. We show how the Chandra X-Ray Observatory could be used to determine the distance to M31 to ... More
Project Icarus: Preliminary Thoughts on the Selection of Probes and Instruments for an Icarus-style Interstellar MissionJun 04 2016In this paper we outline the range of probes and scientific instruments that will be required in order for Icarus to fulfill its scientific mission of exploring a nearby star, its attendant planetary system, and the intervening interstellar medium. Based ... More
Competitive Accretion in Clusters and the IMFJan 26 2000Observations have revealed that most stars are born in clusters. As these clusters typically contain more mass in gas than in stars, accretion can play an important role in determining the final stellar masses. Numerical simulations of gas accretion in ... More
Spiral arm triggering of star formationNov 07 2006We present numerical simulations of the passage of clumpy gas through a galactic spiral shock, the subsequent formation of giant molecular clouds (GMCs) and the triggering of star formation. The spiral shock forms dense clouds while dissipating kinetic ... More
The Formation of Massive Binary StarsJan 13 2005The formation of massive stars in close binary systems is complicated due to their high radiation pressure, the crowded environment and the expected minimum separation for fragmentation being many times greater than the orbital separation. I discuss how ... More
Jordan manifolds and dispersionless KdV equationsOct 01 2000Multicomponent KdV-systems are defined in terms of a set of structure constants and, as shown by Svinolupov, if these define a Jordan algebra the corresponding equations may be said to be integrable, at least in the sense of having higher-order symmetries, ... More
Weyl groups and Elliptic Solutions of the WDVV equationsFeb 04 2008Nov 04 2009A functional ansatz is developed which gives certain elliptic solutions of the Witten-Dijkgraaf-Verlinde-Verlinde (or WDVV) equation. This is based on the elliptic trilogarithm function introduced by Beilinson and Levin. For this to be a solution results ... More
The Astronomical, Astrobiological and Planetary Science Case for Interstellar SpaceflightAug 28 2010A review is presented of the scientific benefits of rapid (v >= 0.1c) interstellar spaceflight. Significant benefits are identified in the fields of interstellar medium studies, stellar astrophysics, planetary science and astrobiology. In the latter three ... More
The Moon as a Recorder of Nearby SupernovaeAug 13 2016The lunar geological record is expected to contain a rich record of the galactic environment of the Solar System, including records of nearby (i.e. less than a few tens of parsecs) supernova explosions. This record will be composed of two principal components: ... More
Parsimony, model adequacy and periodic correlation in forecasting time seriesNov 04 2016The merits of the modelling philosophy of Box \& Jenkins (1970) are illustrated with a summary of our recent work on seasonal river flow forecasting. Specifically, this work demonstrates that the principle of parsimony, which has been questioned by several ... More
Differential and Functional Identities for the Elliptic TrilogarithmMar 13 2009When written in terms of $\vartheta$-functions, the classical Frobenius-Stickelberger pseudo-addition formula takes a very simple form. Generalizations of this functional identity are studied, where the functions involved are derivatives (including derivatives ... More
Competitive Accretion and the IMFJan 13 2005Competitive accretion occurs when stars in a cluster accrete from a shared reservoir of gas. The competition arises due to the relative attraction of stars as a function of their mass and location in the cluster. The low relative motions of the stars ... More
The long-term scientific benefits of a space economyJul 17 2016Utilisation of the material and energy resources of the Solar System will be essential for the development of a sustainable space economy and associated infrastructure. Science will be a major beneficiary of a space economy, even if its major elements ... More
Hopping between Random Locations: Spectrum and InstantonJun 22 2000Euclidean random matrices appear in a broad class of physical problems involving disorder. The problem of determining their spectra can be mapped, using the replica method, into the study of a scalar field theory with an interaction of the type e^(psi^2). ... More
Asteroids in the service of humanityJun 11 2013There are at least three compelling reasons for the human race to initiate a major programme to explore and better understand the 'minor planets' of the Solar System: (1) Enhancing scientific knowledge; (2) Mitigating the impact hazard; and (3) Utilizing ... More
The Scientific Legacy of ApolloNov 28 2012On the 40th anniversary of the last human expedition to the Moon, I review the scientific legacy of the Apollo programme and argue that science would benefit from a human return to the Moon.
Dispelling the myth of robotic efficiency: why human space exploration will tell us more about the Solar System than will robotic exploration aloneMar 28 2012There is a widely held view in the astronomical community that unmanned robotic space vehicles are, and will always be, more efficient explorers of planetary surfaces than astronauts (e.g. Coates, 2001; Clements 2009; Rees 2011). Partly this is due to ... More
Hyperbolic decay time seriesNov 02 2016Hyperbolic decay time series such as, fractional Gaussian noise (FGN) or fractional autoregressive moving-average (FARMA) process, each exhibit two distinct types of behaviour: strong persistence or antipersistence. Beran (1994) characterized the family ... More
The Formation of Massive Stars through Stellar CollisionsNov 14 2001In this review, I present the case for how massive stars may form through stellar collisions. This mechanism requires very high stellar densities, up to 4 orders of magnitude higher than are observed in the cores of dense young clusters. In this model, ... More
Early Evolution of Stellar ClustersAug 24 1999Observations have revealed that most stars are born in clusters. These systems, containing from tens to thousands of stars and typically significant mass in gas in the youngest systems, evolve due to a combination of stellar and star-gas interactions. ... More
Improved spread-location visualizationNov 04 2016The spread-location plot has often been used as a diagnostic plot suitable for many types of fitted statistical models. The spread-location plot which plots the absolute residual or square-root absolute residual versus fitted value along with a robust ... More
Necessary and Sufficient Condition for Nonsingular Fisher Information Matrix in ARMA ModelsNov 04 2016It is demonstrated that a necessary and sufficient condition that the Fisher information matrix of an ARMA model be nonsingular is that the model not be redundant, that is, the autoregressive and moving-average polynomials do not share common roots.
Differential Morphology Between Rest-frame Optical and UV Emission from 1.5 < z < 3 Star-forming GalaxiesOct 07 2010Jan 06 2011We present the results of a comparative study of the rest-frame optical and rest-frame ultraviolet morphological properties of 117 star-forming galaxies (SFGs), including BX, BzK, and Lyman break galaxies with B<24.5, and 15 passive galaxies in the region ... More
The mass-Peak Patch algorithm for fast generation of deep all-sky dark matter halo catalogues and its N-Body validationOct 17 2018We present a detailed description and validation of our massively-parallel update to the mass-Peak Patch method, a fully predictive initial-space algorithm to quickly generate dark matter halo catalogues in very large cosmological volumes. We perform ... More
On higher spin symmetries in de Sitter QFTsNov 20 2015Mar 03 2016We consider the consequences of global higher-spin symmetries in quantum field theories on a fixed de Sitter background of spacetime dimension $D \ge 3$. These symmetries enhance the symmetry group associated with the isometries of the de Sitter background ... More
On the detection of superdiffusive behaviour in time seriesJul 25 2016Nov 17 2016We present a new method for detecting superdiffusive behaviour and for determining rates of superdiffusion in time series data. Our method applies equally to stochastic and deterministic time series data (with no prior knowledge required of the nature ... More
On the Implementation of the 0-1 Test for ChaosJun 08 2009In this paper we address practical aspects of the implementation of the 0-1 test for chaos in deterministic systems. In addition, we present a new formulation of the test which significantly increases its sensitivity. The test can be viewed as a method ... More
Primordial triples and collisions of massive starsJan 29 2013Massive stars are known to have a high multiplicity, with examples of higher order multiples among the nearest and best studied objects. In this paper we study hierarchical multiple systems (an inner binary as a component of a wider binary) of massive ... More
Limits on initial mass segregation in young clustersMar 23 2009Mar 24 2009Mass segregation is observed in many star clusters, including several that are less than a few Myr old. Timescale arguments are frequently used to argue that these clusters must be displaying primordial segregation, because they are too young to be dynamically ... More
On the detection of superdiffusive behaviour in time seriesJul 25 2016Dec 21 2016We present a new method for detecting superdiffusive behaviour and for determining rates of superdiffusion in time series data. Our method applies equally to stochastic and deterministic time series data (with no prior knowledge required of the nature ... More
Improved multivariate portmanteau testNov 02 2016A new portmanteau diagnostic test for vector autoregressive moving average (VARMA) models that is based on the determinant of the standardized multivariate residual autocorrelations is derived. The new test statistic may be considered an extension of ... More
Nonleptonic Two-Body Decays of D Mesons in Broken SU(3)Feb 10 1995Decays of the D mesons to two pseudoscalars, to two vectors, and to pseudoscalar plus vector are discussed in the context of broken flavor SU(3). A few assumptions are used to reduce the number of parameters. Amplitudes are fit to the available data, ... More
Photon impact factor and $k_T$-factorization for DIS in the next-to-leading orderJul 16 2012Jul 27 2014The photon impact factor for the BFKL pomeron is calculated in the next-to-leading order (NLO) approximation using the operator expansion in Wilson lines. The result is represented as a NLO $k_T$-factorization formula for the structure functions of small-$x$ ... More
Does sub-cluster merging accelerate mass segregation in local star formation?Aug 03 2009The nearest site of massive star formation in Orion is dominated by the Trapezium subsystem, with its four OB stars and numerous companions. The question of how these stars came to be in such close proximity has implications for our understanding of massive ... More
Group Averaging for de Sitter free fieldsOct 28 2008Perturbative gravity about global de Sitter space is subject to linearization-stability constraints. Such constraints imply that quantum states of matter fields couple consistently to gravity {\it only} if the matter state has vanishing de Sitter charges; ... More
The IR stability of de Sitter QFT: results at all ordersOct 26 2010Nov 19 2010We show that the Hartle-Hawking vacuum for theories of interacting massive scalars in de Sitter space is both perturbatively well-defined and stable in the IR. Correlation functions in this state may be computed on the Euclidean section and Wick-rotated ... More
Testing for Chaos in Deterministic Systems with NoiseOct 15 2004Recently, we introduced a new test for distinguishing regular from chaotic dynamics in deterministic dynamical systems and argued that the test had certain advantages over the traditional test for chaos using the maximal Lyapunov exponent. In this paper, ... More
A New Test for ChaosAug 26 2002Jan 17 2003We describe a new test for determining whether a given deterministic dynamical system is chaotic or nonchaotic. (This is an alternative to the usual approach of computing the largest Lyapunov exponent.) Our method is a 0-1 test for chaos (the output is ... More
Fitting MA(q) Models in the Closed Invertible RegionNov 15 2016The use of reparameterization in the maximization of the likelihood function of the MA(q) model is discussed. A general method for testing for the presence of a parameter estimate on the boundary of an MA(q) model is presented. This test is illustrated ... More
Estimating the Power Spectrum of the Cosmic Microwave BackgroundAug 22 1997Feb 25 1998We develop two methods for estimating the power spectrum, C_l, of the cosmic microwave background (CMB) from data and apply them to the COBE/DMR and Saskatoon datasets. One method involves a direct evaluation of the likelihood function, and the other ... More
NLO evolution of color dipolesOct 23 2007The small-$x$ deep inelastic scattering in the saturation region is governed by the non-linear evolution of Wilson-line operators. In the leading logarithmic approximation it is given by the BK equation for the evolution of color dipoles. In the next-to-leading ... More
On the detection of superdiffusive behaviour in time seriesJul 25 2016We present a new method for detecting superdiffusive behaviour and for determining rates of superdiffusion in time series data. Our method applies equally to stochastic and deterministic time series data and relies on one realisation (ie one sample path) ... More
On modular mod $\ell$ Galois representations with exceptional imagesNov 06 2003We give a parametrization of the possible Serre invariants $(N,k,\nu)$ of modular mod $\ell$ Galois representations of the exceptional types $A_4$, $S_4$, $A_5$, in terms of local data attached to the fields cut out by the associated projective representations. ... More
Numerical calculation of second order perturbationsJul 16 2009Sep 17 2009We numerically solve the Klein-Gordon equation at second order in cosmological perturbation theory in closed form for a single scalar field, describing the method employed in detail. We use the slow-roll version of the second order source term and argue ... More
On the Validity of the 0-1 Test for ChaosJun 08 2009In this paper, we present a theoretical justification of the 0-1 test for chaos. In particular, we show that with probability one, the test yields 0 for periodic and quasiperiodic dynamics, and 1 for sufficiently chaotic dynamics.
A Huygens principle for diffusion and anomalous diffusion in spatially extended systemsApr 12 2013May 09 2013We present a universal view on diffusive behaviour in chaotic spatially extended systems for anisotropic and isotropic media. For anisotropic systems, strong chaos leads to diffusive behaviour (Brownian motion with drift) and weak chaos leads to superdiffusive ... More
Conformal kernel for NLO BFKL equation in ${\cal N}$=4 SYMDec 18 2008Using the requirement of M\"{o}bius invariance of ${\cal N}$=4 SYM amplitudes in the Regge limit we restore the conformal NLO BFKL kernel out of the eigenvalues known from the forward NLO BFKL result.
NLO evolution of color dipoles in N=4 SYMMar 30 2009High-energy behavior of amplitudes in a gauge theory can be reformulated in terms of the evolution of Wilson-line operators. In the leading logarithmic approximation it is given by the conformally invariant BK equation for the evolution of color dipoles. ... More
The IR stability of de Sitter: Loop corrections to scalar propagatorsMay 31 2010Oct 26 2010We compute 1-loop corrections to Lorentz-signature de Sitter-invariant 2-point functions defined by the interacting Euclidean vacuum for massive scalar quantum fields with cubic and quartic interactions. Our results apply to all masses for which the free ... More
Computer Algebra Derivation of the Bias of Burg EstimatorsNov 04 2016A symbolic method is discussed which can be used to obtain the asymptotic bias and variance to order $O(1/n)$ for estimators in stationary time series. Using this method the bias to $O(1/n)$ of the Burg estimator in AR(1) and AR(2) models is shown to ... More
The Impact of baryonic physics on the kinetic Sunyaev-Zel'dovich EffectOct 08 2017Nov 30 2017Poorly understood "baryonic physics" impacts our ability to predict the power spectrum of the kinetic Sunyaev-Zel'dovich (kSZ) effect. We study this in one sample high resolution simulation of galaxy formation and feedback, Illustris. The high resolution ... More
The Absorbers Toward CSO 118: Superclustering at {z~3}, or an Intrinsic Absorption Complex?May 04 2001We present two low resolution (R~1300) high signal-to-noise spectra (Wr,lim~50mA) of the quasar CSO 118 (zem=2.97) taken with the Hobby-Eberly Telescope Marcario Low Resolution Spectrograph. We detect eight absorbers selected by the CIV 1548,1550 absorption ... More
Rapidity evolution of Wilson lines at the next-to-leading orderSep 29 2013Nov 26 2013At high energies particles move very fast so the proper degrees of freedom for the fast gluons moving along the straight lines are Wilson-line operators - infinite gauge factors ordered along the line. In the framework of operator expansion in Wilson ... More
Photon impact factor in the next-to-leading orderSep 23 2010An analytic coordinate-space expression for the next-to-leading order photon impact factor for small-$x$ deep inelastic scattering is calculated using the operator expansion in Wilson lines.
Photon counting with loop detectorJun 22 2002We propose a design for a photon counting detector capable of resolving multiphoton events. The basic element of the setup is a fiber loop, which traps the input field with the help of a fast electrooptic switch. A single weakly coupled avalanche photodiode ... More
Broadband nature of power spectra for intermittent Maps with summable and nonsummable decay of correlationsOct 31 2015Mar 30 2016We present results on the broadband nature of the power spectrum $S(\omega)$, $\omega\in(0,2\pi)$, for a large class of nonuniformly expanding maps with summable and nonsummable decay of correlations. In particular, we consider a class of intermittent ... More
Faster ARMA maximum likelihood estimationNov 03 2016A new likelihood based AR approximation is given for ARMA models. The usual algorithms for the computation of the likelihood of an ARMA model require $O(n)$ flops per function evaluation. Using our new approximation, an algorithm is developed which requires ... More
Partial autocorrelation parameterization for subset autoregressionNov 04 2016A new version of the partial autocorrelation plot and a new family of subset autoregressive models are introduced. A comprehensive approach to model identification, estimation and diagnostic checking is developed for these models. These models are better ... More
Central limit theorems and suppression of anomalous diffusion for systems with symmetryApr 03 2014Feb 23 2015We give general conditions for the central limit theorem and weak convergence to Brownian motion (the weak invariance principle / functional central limit theorem) to hold for observables of compact group extensions of nonuniformly expanding maps. In ... More
Towards an understanding of the Of?p star HD 191612: optical spectroscopyJul 04 2007We present extensive optical spectroscopy of the early-type magnetic star HD 191612 (O6.5f?pe-O8fp). The Balmer and HeI lines show strongly variable emission which is highly reproducible on a well-determined 538-d period. Metal lines and HeII absorptions ... More
MOA-2012-BLG-505Lb: A super-Earth mass planet probably in the Galactic bulgeMar 31 2017May 19 2017We report the discovery of a super-Earth mass planet in the microlensing event MOA-2012-BLG-505. This event has the second shortest event timescale of $t_{\rm E}=10 \pm 1$ days where the observed data show evidence of planetary companion. Our 15 minute ... More
EKR sets for large $n$ and $r$Oct 28 2012Let $\A\subset\binom{[n]}{r}$ be a compressed, intersecting family and let $X\subset[n]$. Let $\A(X)={A\in\A:A\cap X\ne\emptyset}$ and $\S_{n,r}=\binom{[n]}{r}({1})$. Motivated by the Erd\H{o}s-Ko-Rado theorem, Borg asked for which $X\subset[2,n]$ do ... More
A Period and a Prediction for the Of?p Spectrum Alternator HD 191612Sep 08 2004Nov 12 2004The observational picture of the enigmatic O-type spectrum variable HD191612 has been sharpened substantially. A symmetrical, low-amplitude light curve with a period near 540 d has recently been reported from Hipparcos photometry. This period satisfies ... More
Einstein metrics on tangent bundles of spheresFeb 28 2002We give an elementary treatment of the existence of complete Kahler-Einstein metrics with nonpositive Einstein constant and underlying manifold diffeomorphic to the tangent bundle of the (n+1)-sphere.
The Use of Extraterrestrial Resources to Facilitate Space Science and ExplorationMay 25 2016May 26 2016To-date, all human economic activity has depended on the resources of a single planet, and it has long been recognized that developments in space exploration could in principle open our closed planetary economy to external resources of energy and raw ... More
Fixed and Market Pricing for Cloud ServicesJan 26 2012This paper considers two simple pricing schemes for selling cloud instances and studies the trade-off between them. We characterize the equilibrium for the hybrid system where arriving jobs can choose between fixed or the market based pricing. We provide ... More
The brown dwarf desert as a consequence of orbital migrationNov 30 2001We show that the dearth of brown dwarfs in short-period orbits around Solar-mass stars - the brown dwarf desert - can be understood as a consequence of inward migration within an evolving protoplanetary disc. Brown dwarf secondaries forming at the same ... More
Symmetries of F-manifolds with eventual identities and special families of connectionsMar 10 2011Sep 24 2012We construct a duality for F-manifolds with eventual identities and special families of connections and we describe its interactions with several well-known constructions from the theory of Frobenius and F-manifolds.
Fundamental limits to signal integrity in nonlinear parametric optical circulatorsNov 06 2017We characterize the response of a parametric nonlinear optical circulator to realistic signals that have finite bandwidths. Our results show that intermodulation distortion (IMD), rather than pump depletion or compression, limits the maximal operating ... More
Logarithmic deformations of the rational superpotential/Landau-Ginzburg construction of solutions of the WDVV equationsMay 30 2006The superpotential in the Landau-Ginzburg construction of solutions to the Witten-Dijkgraaf-Verlinde-Verlinde (or WDVV) equations is modified to include logarithmic terms. This results in deformations - quadratic in the deformation parameters - of the ... More
Direct, Loss-Tolerant Characterization of Nonclassical Photon StatisticsJun 20 2006We experimentally investigate a method of directly characterizing the photon number distribution of nonclassical light beams that is tolerant to losses and makes use only of standard binary detectors. This is achieved in a single measurement by calibrating ... More
Binary systems and stellar mergers in massive star formationJun 28 2005We present a model for the formation of high-mass close binary systems in the context of forming massive stars through gas accretion in the centres of stellar clusters. A low-mass wide binary evolves under mass accretion towards a high-mass close binary, ... More
Ionisation-induced star formation III: Effects of external triggering on the IMF in clustersFeb 07 2012We report on Smoothed Particle Hydrodynamics (SPH) simulations of the impact on a turbulent $\sim2\times10^{3}$ M$_{\odot}$ star--forming molecular cloud of irradiation by an external source of ionizing photons. We find that the ionizing radiation has ... More
Modeling the near-UV band of GK stars, Paper III: Dependence on abundance patternApr 17 2013We extend the grid of NLTE models presented in Paper II to explore variations in abundance pattern in two ways: 1) The adoption of the Asplund et al. (2009) (GASS10) abundances, 2) For stars of metallicity, [M/H], of -0.5, the adoption of a non-solar ... More
Gravitationally dresed RG flows and zig-zag invariant stringsJul 29 1998Sep 30 1998We propose a world-sheet realization of the zigzag-invariant bosonic and fermionic strings as a perturbed Wess-Zumino-Novikov-Witten model at large negative level $k$ on a group manifold $G$ coupled to 2D gravity. In the large $k$ limit the zigzag symmetry ... More
Lunar Exploration: Opening a Window into the History and Evolution of the Inner Solar SystemAug 12 2014The lunar geological record contains a rich archive of the history of the inner Solar System, including information relevant to understanding the origin and evolution of the Earth-Moon system, the geological evolution of rocky planets, and our local cosmic ... More
Self-tuning in an Outgoing Brane Wave ModelApr 28 2000May 17 2000We introduce a new brane-world model in which the bulk solution consists of outgoing plane waves. This is an exact solution to string theory with no naked singularities. The recently discussed self-tuning mechanism to cancel the cosmological constant ... More
Dubrovin's duality for $F$-manifolds with eventual identitiesJun 03 2010A vector field E on an F-manifold (M, o, e) is an eventual identity if it is invertible and the multiplication X*Y := X o Y o E^{-1} defines a new F-manifold structure on M. We give a characterization of such eventual identities, this being a problem ... More
Improved Pena-Rodriguez Portmanteau TestNov 04 2016Several problems with the diagnostic check suggested by Pena and Rodriguez [2002. A powerful portmanteau test of lack of fit for time series. J. Amer. Statist. Assoc. 97, 601-610.] are noted and an improved Monte-Carlo version of this test is suggested. ... More
Very Large Telescope deep echelle spectroscopy of Galactic planetary nebulae NGC 6153, M 1-42 and Hf 2-2Jun 09 2016We present deep spectroscopy of three Galactic planetary nebulae (PNe) with large abundance discrepancy factors (ADFs): NGC6153, M1-42 and Hf2-2. The spectra were obtained with VLT/UVES and cover the whole optical range (3040-11,000 A) with a spectral ... More
New Maser Emission from Nonmetastable Ammonia in NGC 7538. IV. Coincident Masers in Adjacent States of Para-ammoniaJan 01 2014We present the first detection of para-ammonia masers in NGC 7538: multiple epochs of observation of the 14NH3 (J,K) = (10,8) and (9,8) lines. We detect both thermal absorption and nonthermal emission in the (10,8) and (9,8) transitions and the absence ... More
Star formation through gravitational collapse and competitive accretionApr 28 2006Competitive accretion, a process to explain the origin of the IMF, occurs when stars in a common gravitational potential accrete from a distributed gaseous component. We show that concerns recently raised on the efficiency of competitive accretion are ... More
High Resolution Spectroscopy and High Contrast Imaging with the ELT : looking for O$_2$ in Proxima bJan 30 2019We research the requirements of High Contrast Imaging when combined with the cross correlation (CC) of high resolution spectra with known spectroscopic templates for detecting and characterising exoplanets in reflected light. We simulate applying the ... More
Encoding fairness in a synchronous concurrent program algebra: extended version with proofsMay 04 2018Concurrent program refinement algebra provides a suitable basis for supporting mechanised reasoning about shared-memory concurrent programs in a compositional manner, for example, it supports the rely/guarantee approach of Jones. The algebra makes use ... More
Power Computations for Intervention AnalysisNov 05 2016In many intervention analysis applications time series data may be expensive or otherwise difficult to collect. In this case the power function is helpful since it can be used to determine the probability that a proposed intervention analysis application ... More
Conformally flat pencils of metrics, Frobenius structures and a modified Saito constructionFeb 07 2005Mar 02 2005The structure of a Frobenius manifold encodes the geometry associated with a flat pencil of metrics. However, as shown in the authors' earlier work, much of the structure comes from the compatibility properties of the pencil rather than from the flatness ... More
Sparsity-Exploiting Moment-Based Relaxations of the Optimal Power Flow ProblemApr 20 2014Nov 17 2014Convex relaxations of non-convex optimal power flow (OPF) problems have recently attracted significant interest. While existing relaxations globally solve many OPF problems, there are practical problems for which existing relaxations fail to yield physically ... More
Mutual information between thermo-field doubles and disconnected holographic boundariesNov 13 2012Jun 10 2013We use mutual information as a measure of the entanglement between 'physical' and thermo-field double degrees of freedom in field theories at finite temperature. We compute this "thermo-mutual information" in simple toy models: a quantum mechanics two-site ... More
Orbital migration and the brown dwarf desertOct 08 2002The orbital elements of extreme mass ratio binaries will be modified by interactions with surrounding circumstellar disks. For brown dwarf companions to Solar-type stars the resulting orbital migration is sufficient to drive short period systems to merger, ... More
Novikov algebras and a classification of multicomponent Camassa-Holm equationsSep 12 2013Jan 30 2014A class of multi-component integrable systems associated to Novikov algebras, which interpolate between KdV and Camassa-Holm type equations, is obtained. The construction is based on the classification of low-dimensional Novikov algebras by Bai and Meng. ... More