1,011 research outputs found
Scattering theory with finite-gap backgrounds: Transformation operators and characteristic properties of scattering data
We develop direct and inverse scattering theory for Jacobi operators (doubly
infinite second order difference operators) with steplike coefficients which
are asymptotically close to different finite-gap quasi-periodic coefficients on
different sides. We give necessary and sufficient conditions for the scattering
data in the case of perturbations with finite second (or higher) moment.Comment: 23 page
Scattering Theory for Jacobi Operators with Steplike Quasi-Periodic Background
We develop direct and inverse scattering theory for Jacobi operators with
steplike quasi-periodic finite-gap background in the same isospectral class. We
derive the corresponding Gel'fand-Levitan-Marchenko equation and find minimal
scattering data which determine the perturbed operator uniquely. In addition,
we show how the transmission coefficients can be reconstructed from the
eigenvalues and one of the reflection coefficients.Comment: 14 page
From Coulomb excitation cross sections to non-resonant astrophysical rates in three-body systems: Ne case
Coulomb and nuclear dissociation of Ne on light and heavy targets are
studied theoretically. The dipole E1 strength function is determined in a broad
energy range including energies of astrophysical interest. Dependence of the
strength function on different parameters of the Ne ground state
structure and continuum dynamics is analyzed in a three-body model. The
discovered dependence plays an important role for studies of the strength
functions for the three-body E1 dissociation and radiative capture. The
constraints on the configuration mixing in Ne and on
-wave interaction in the O+ channel are imposed based on
experimental data for Ne Coulomb dissociation on heavy target.Comment: 12 pages, 13 figure
Emerg. Infect. Dis
The multidrug-resistant (MDR) Salmonella enterica serotype Newport strain that produces CMY-2 β-lactamase(Newport MDR-AmpC) was the source of sporadic cases and outbreaks in humans in France during 2000–2005. Because this strain was not detected in food animals, it was most likely introduced into France through imported food products
On UHECR energy estimation algorithms based on the measurement of electromagnetic component parameters in EAS
Model calculations are performed of extensive air shower (EAS) component
energies using a variety of hadronic interaction parameters. A conversion
factor from electromagnetic component energy to the energy of ultra-high energy
cosmic rays (UHECRs) and its model and primary mass dependence is studied. It
is shown that model dependence of the factor minimizes under the necessary
condition of the same maximum position and muon content of simulated showers.Comment: contracted version is accepted for publication in Doklady Physic
Long-Time Asymptotics of Perturbed Finite-Gap Korteweg-de Vries Solutions
We apply the method of nonlinear steepest descent to compute the long-time
asymptotics of solutions of the Korteweg--de Vries equation which are decaying
perturbations of a quasi-periodic finite-gap background solution. We compute a
nonlinear dispersion relation and show that the plane splits into
soliton regions which are interlaced by oscillatory regions, where
is the number of spectral gaps.
In the soliton regions the solution is asymptotically given by a number of
solitons travelling on top of finite-gap solutions which are in the same
isospectral class as the background solution. In the oscillatory region the
solution can be described by a modulated finite-gap solution plus a decaying
dispersive tail. The modulation is given by phase transition on the isospectral
torus and is, together with the dispersive tail, explicitly characterized in
terms of Abelian integrals on the underlying hyperelliptic curve.Comment: 45 pages. arXiv admin note: substantial text overlap with
arXiv:0705.034
Large deep neural networks for MS lesion segmentation
Multiple sclerosis (MS) is a multi-factorial autoimmune disorder, characterized by spatial and temporal dissemination of brain lesions that are visible in T2-weighted and Proton Density (PD) MRI. Assessment of lesion burden and is useful for monitoring the course of the disease, and assessing correlates of clinical outcomes. Although there are established semi-automated methods to measure lesion volume, most of them require human interaction and editing, which are time consuming and limits the ability to analyze large sets of data with high accuracy. The primary objective of this work is to improve existing segmentation algorithms and accelerate the time consuming operation of identifying and validating MS lesions. In this paper, a Deep Neural Network for MS Lesion Segmentation is implemented. The MS lesion samples are extracted from the Partners Comprehensive Longitudinal Investigation of Multiple Sclerosis (CLIMB) study. A set of 900 subjects with T2, PD and a manually corrected label map images were used to train a Deep Neural Network and identify MS lesions. Initial tests using this network achieved a 90% accuracy rate. A secondary goal was to enable this data repository for big data analysis by using this algorithm to segment the remaining cases available in the CLIMB repository
In memoriam of Alexander Golovin (1939–2013)
No abstract available
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