Open Access Repositories: Recent submissions
Now showing items 1261-1280 of 4204
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Total Positivity in Markov Structures
(Institute of Mathematical StatisticsAnnals of Statistics, 2017-06)We discuss properties of distributions that are multivariate totally positive of order two (MTP$_{2}$) related to conditional independence. In particular, we show that any independence model generated by an MTP$_{2}$ ...
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ππ→πγ$^{∗}$ amplitude and the resonant ρ→πγ$^{∗}$ transition from lattice QCD
(American Physical SocietyPhysical Review D, 2016-06-10)We present a determination of the P-wave ππ→πγ$^{⋆}$ transition amplitude from lattice quantum chromodynamics. Matrix elements of the vector current in a finite volume are extracted from three-point correlation functions, ...
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Second-Order Asymptotics of Visible Mixed Quantum Source Coding via Universal Codes
(IEEEIEEE Transactions on Information Theory, 2016-05-23)The simplest example of a quantum information source with memory is a mixed source, which emits signals entirely from one of two memoryless quantum sources with given $\textit{a priori}$ probabilities. Considering a mixed ...
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Preconditioned ADMM with nonlinear operator constraint
(SpringerIFIP Advances in Information and Communication Technology, 2016)We are presenting a modification of the well-known Alternating Direction Method of Multipliers (ADMM) algorithm with additional preconditioning that aims at solving convex optimisation problems with nonlinear operator ...
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Multi-Contrast MRI Reconstruction with Structure-Guided Total Variation
(Society for Industrial and Applied MathematicsSIAM Journal on Imaging Sciences, 2016-08-04)Magnetic resonance imaging (MRI) is a versatile imaging technique that allows different contrasts depending on the acquisition parameters. Many clinical imaging studies acquire MRI data for more than one of these contrasts—such ...
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Turning on gravity with the Higgs mechanism
(IOP PublishingClassical and Quantum Gravity, 2016-06-21)We investigate how a Higgs mechanism could be responsible for the emergence of gravity in extensions of Einstein theory, with a suitable low energy limit. In this scenario, at high energies, symmetry restoration could "turn ...
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On the quadratic invariant of binary sextics
(Cambridge University PressMathematical Proceedings of the Cambridge Philosophical Society, 2016-07-28)We provide a geometric characterisation of binary sextics with vanishing quadratic invariant.
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Unsteady flow and particle migration in dense, non-Brownian suspensions
(AIPJournal of Rheology, 2016)We present experimental results on dense corn-starch suspensions as examples of non-Brownian, nearly-hard particles that undergo continuous and discontinuous shear thickening (CST and DST) at intermediate and high densities ...
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Dewatering of fibre suspensions by pressure filtration
(AIP PublishingPhysics of Fluids, 2016-06-09)A theoretical and experimental study of dewatering of fibre suspensions by uniaxial compression is presented. Solutions of a one-dimensional model are discussed and asymptotic limits of fast and slow compression are explored. ...
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On turbulence driven by axial precession and tidal evolution of the spin–orbit angle of close-in giant planets
(Oxford University PressMonthly Notices of the Royal Astronomical Society, 2016-05-16)The spin axis of a rotationally deformed planet is forced to precess about its orbital angular momentum vector, due to the tidal gravity of its host star, if these directions are misaligned. This induces internal fluid ...
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Gravitoturbulence in magnetized protostellar discs
(Oxford University PressMonthly Notices of the Royal Astronomical Society, 2016-05-11)Gravitational instability (GI) features in several aspects of protostellar disc evolution, most notably in angular momentum transport, fragmentation, and the outbursts exemplified by FU Ori and EX Lupi systems. The outer ...
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Interaction of turbulence with the leading-edge stagnation point of a thin aerofoil
(Cambridge University PressJournal of Fluid Mechanics, 2016)An asymptotic model is constructed to analyse the interaction of turbulence generated far upstream with a thin elliptic-nosed solid body in uniform flow. The leading-edge stagnation point causes significant deformation of ...
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Invariant Distributions and Tensor Tomography for Gaussian Thermostats
(International PressCommunications in Analysis and Geometry, 2016)In this paper we consider the Gaussian thermostat ray transforms on both closed Riemannian surfaces and compact Riemannian surfaces with boundary. We establish certain results on the injectivity of the thermostat ray ...
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A Quantum Paradox of Choice: More Freedom Makes Summoning a Quantum State Harder
(American Physical SocietyPhysical Review A, 2016)The properties of quantum information in space-time can be investigated by studying operational tasks, such as ‘summoning’, in which an unknown quantum state is supplied at one point, and a call is made at another for it ...
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Turbulent mixing, restratification, and phytoplankton growth at a submesoscale eddy
(WileyGeophysical Research Letters, 2016-05-13)High-resolution large-eddy simulations are used to study the influence of submesoscale mixed layer instability and small-scale turbulence on phytoplankton growth in light-limited conditions. Four simulations are considered ...
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Bilevel Parameter Learning for Higher-Order Total Variation Regularisation Models
(SpringerJournal of Mathematical Imaging and Vision, 2016-06-01)We consider a bilevel optimisation approach for parameter learning in higher-order total variation image reconstruction models. Apart from the least squares cost functional, naturally used in bilevel learning, we propose ...
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Dimensional reduction in numerical relativity: Modified cartoon formalism and regularization
(World Scientific Publishing CompanyInternational Journal of Modern Physics D, 2016-06-01)We present in detail the Einstein equations in the Baumgarte–Shapiro–Shibata–Nakamura formulation for the case of D-dimensional spacetimes with SO(D−d)isometry based on a method originally introduced in Ref. 1. Regularized ...
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Numerical simulations of stellar collapse in scalar-tensor theories of gravity
(Institute of PhysicsClassical and Quantum Gravity, 2016-05-31)We present numerical-relativity simulations of spherically symmetric core collapse and compact-object formation in scalar-tensor theories of gravity. The additional scalar degree of freedom introduces a propagating monopole ...
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Numerical simulations of stellar collapse in scalar-tensor theories of gravity
(Institute of PhysicsClassical and Quantum Gravity, 2016-05-31)We present numerical-relativity simulations of spherically symmetric core collapse and compact-object formation in scalar-tensor theories of gravity. The additional scalar degree of freedom introduces a propagating monopole ...
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A short proof that every finite graph has a tree-decomposition displaying its tangles
(ElsevierEuropean Journal of Combinatorics, 2016-06-08)We give a short proof that every finite graph (or matroid) has a tree-decomposition that displays all maximal tangles. This theorem for graphs is a central result of the graph minors project of Robertson and Seymour and ...
