1,230 research outputs found
Image restoration using the Q-Ising spin glass
We investigate static and dynamic properties of gray-scale image restoration
(GSIR) by making use of the Q-Ising spin glass model, whose ladder symmetry
allows to take in account the distance between two spins. We thus give an
explicit expression of the Hamming distance between the original and restored
images as a function of the hyper-parameters in the mean field limit. Finally,
numerical simulations for real-world pictures are carried out to prove the
efficiency of our model.Comment: 27pages, 13figures, revte
Does one size fit all? An update on chronic ventilatory support in different respiratory illnesses
Home noninvasive ventilation (HNIV) improves outcomes in different disease categories. In this article, we discuss indications for when and how to initiate HNIV in COPD, obesity hypoventilation syndrome (OHS) and neuromuscular disorders (NMD). While in COPD, significant diurnal hypercapnia and high-intensity HNIV are essential ingredients for success, in NMD and OHS, early respiratory changes are best detected during sleep through oxy-capnography associated (or not) with respiratory polygraphy. In COPD and OHS, it is crucial to consider the coexistence of obstructive sleep apnoea because treatment with continuous positive airway pressure may be the simplest and most effective treatment that should be proposed even in hypercapnic patients as first-line therapy. In NMD, the need for continuous HNIV and eventual switching to tracheostomy ventilation makes this group’s management more challenging. Achieving successful HNIV by improving quality of sleep, quality of life and keeping a good adherence to the therapy is a challenge, above all in COPD patients. In OHS patients, on top of HNIV, initiation of other interventions such as weight loss management is crucial. More resources should be invested in improving all these aspects. Telemonitoring represents a promising method to improve titration and follow-up of HNIV
Multi-State Image Restoration by Transmission of Bit-Decomposed Data
We report on the restoration of gray-scale image when it is decomposed into a
binary form before transmission. We assume that a gray-scale image expressed by
a set of Q-Ising spins is first decomposed into an expression using Ising
(binary) spins by means of the threshold division, namely, we produce (Q-1)
binary Ising spins from a Q-Ising spin by the function F(\sigma_i - m) = 1 if
the input data \sigma_i \in {0,.....,Q-1} is \sigma_i \geq m and 0 otherwise,
where m \in {1,....,Q-1} is the threshold value. The effects of noise are
different from the case where the raw Q-Ising values are sent. We investigate
which is more effective to use the binary data for transmission or to send the
raw Q-Ising values. By using the mean-field model, we first analyze the
performance of our method quantitatively. Then we obtain the static and
dynamical properties of restoration using the bit-decomposed data. In order to
investigate what kind of original picture is efficiently restored by our
method, the standard image in two dimensions is simulated by the mean-field
annealing, and we compare the performance of our method with that using the
Q-Ising form. We show that our method is more efficient than the one using the
Q-Ising form when the original picture has large parts in which the nearest
neighboring pixels take close values.Comment: latex 24 pages using REVTEX, 10 figures, 4 table
Application of the quantum spin glass theory to image restoration
Quantum fluctuation is introduced into the Markov random fields (MRF's) model
for image restoration in the context of Bayesian approach. We investigate the
dependence of the quantum fluctuation on the quality of BW image restoration by
making use of statistical mechanics. We find that the maximum posterior
marginal (MPM) estimate based on the quantum fluctuation gives a fine
restoration in comparison with the maximum a posterior (MAP) estimate or the
thermal fluctuation based MPM estimate.Comment: 19 pages, 9 figures, 1 table, RevTe
Image restoration using the chiral Potts spin-glass
We report on the image reconstruction (IR) problem by making use of the
random chiral q-state Potts model, whose Hamiltonian possesses the same gauge
invariance as the usual Ising spin glass model. We show that the pixel
representation by means of the Potts variables is suitable for the gray-scale
level image which can not be represented by the Ising model. We find that the
IR quality is highly improved by the presence of a glassy term, besides the
usual ferromagnetic term under random external fields, as very recently pointed
out by Nishimori and Wong. We give the exact solution of the infinite range
model with q=3, the three gray-scale level case. In order to check our
analytical result and the efficiency of our model, 2D Monte Carlo simulations
have been carried out on real-world pictures with three and eight gray-scale
levels.Comment: RevTex 13 pages, 10 figure
Effect of inhaled bronchodilators on inspiratory capacity and dyspnoea at rest in COPD
It has been shown that patients with chronic obstructive pulmonary disease (COPD) develop dynamic hyperinflation (DH), which contributes to dyspnoea and exercise intolerance. Formoterol, salmeterol and oxitropium have been recommended for maintenance therapy in COPD patients, but their effect on DH has only been assessed for salmeterol. The aim of the present study was to compare the acute effect of four inhaled bronchodilators (salbutamol, formoterol, salmeterol and oxitropium) and placebo on forced expiratory volume in one second, inspiratory capacity, forced vital capacity and dyspnoea in COPD patients. A cross-over, randomised, double-blind, placebo-controlled study was carried out on 20 COPD patients. Patients underwent pulmonary function testing and dyspnoea evaluation, in basal condition and 5, 15, 30, 60 and 120 min after bronchodilator or placebo administration. The results indicate that in chronic obstructive pulmonary disease patients with decreased baseline inspiratory capacity, there was a much greater increase of inspiratory capacity after bronchodilator administration, which correlated closely with the improvement of dyspnoea sensation at rest. For all bronchodilators used, inspiratory capacity reversibility should be tested at 30 min following the bronchodilator. On average, formoterol elicited the greatest increase in inspiratory capacity than the other bronchodilators used, though the difference was significant only with salmeterol and oxitropium. The potential advantage of formoterol needs to be tested in a larger patient population
Thermodynamic Properties of Holographic Multiquark and the Multiquark Star
We study thermodynamic properties of the multiquark nuclear matter. The
dependence of the equation of state on the colour charges is explored both
analytically and numerically in the limits where the baryon density is small
and large at fixed temperature between the gluon deconfinement and chiral
symmetry restoration. The gravitational stability of the hypothetical
multiquark stars are discussed using the Tolman-Oppenheimer-Volkoff equation.
Since the equations of state of the multiquarks can be well approximated by
different power laws for small and large density, the content of the multiquark
stars has the core and crust structure. We found that most of the mass of the
star comes from the crust region where the density is relatively small. The
mass limit of the multiquark star is determined as well as its relation to the
star radius. For typical energy density scale of ,
the converging mass and radius of the hypothetical multiquark star in the limit
of large central density are approximately solar mass and 15-27 km.
The adiabatic index and sound speed distributions of the multiquark matter in
the star are also calculated and discussed. The sound speed never exceeds the
speed of light and the multiquark matters are thus compressible even at high
density and pressure.Comment: 27 pages, 17 figures, 1 table, JHEP versio
Markedly Divergent Tree Assemblage Responses to Tropical Forest Loss and Fragmentation across a Strong Seasonality Gradient
We examine the effects of forest fragmentation on the structure and composition of tree assemblages within three seasonal and aseasonal forest types of southern Brazil, including evergreen, Araucaria, and deciduous forests. We sampled three southernmost Atlantic Forest landscapes, including the largest continuous forest protected areas within each forest type. Tree assemblages in each forest type were sampled within 10 plots of 0.1 ha in both continuous forests and 10 adjacent forest fragments. All trees within each plot were assigned to trait categories describing their regeneration strategy, vertical stratification, seed-dispersal mode, seed size, and wood density. We detected differences among both forest types and landscape contexts in terms of overall tree species richness, and the density and species richness of different functional groups in terms of regeneration strategy, seed dispersal mode and woody density. Overall, evergreen forest fragments exhibited the largest deviations from continuous forest plots in assemblage structure. Evergreen, Araucaria and deciduous forests diverge in the functional composition of tree floras, particularly in relation to regeneration strategy and stress tolerance. By supporting a more diversified light-demanding and stress-tolerant flora with reduced richness and abundance of shade-tolerant, old-growth species, both deciduous and Araucaria forest tree assemblages are more intrinsically resilient to contemporary human-disturbances, including fragmentation-induced edge effects, in terms of species erosion and functional shifts. We suggest that these intrinsic differences in the direction and magnitude of responses to changes in landscape structure between forest types should guide a wide range of conservation strategies in restoring fragmented tropical forest landscapes worldwide
Rare B Decays with a HyperCP Particle of Spin One
In light of recent experimental information from the CLEO, BaBar, KTeV, and
Belle collaborations, we investigate some consequences of the possibility that
a light spin-one particle is responsible for the three Sigma^+ -> p mu^+ mu^-
events observed by the HyperCP experiment. In particular, allowing the new
particle to have both vector and axial-vector couplings to ordinary fermions,
we systematically study its contributions to various processes involving
b-flavored mesons, including B-Bbar mixing as well as leptonic, inclusive, and
exclusive B decays. Using the latest experimental data, we extract bounds on
its couplings and subsequently estimate upper limits for the branching ratios
of a number of B decays with the new particle. This can serve to guide
experimental searches for the particle in order to help confirm or refute its
existence.Comment: 17 pages, 3 figures; discussion on spin-0 case modified, few errors
corrected, main conclusions unchange
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