7,005 research outputs found
Eikonal profile functions and amplitudes for and scattering
The eikonal profile function obtained from the Model of the Stochastic
Vacuum is parametrized in a form suitable for comparison with experiment. The
amplitude and the extended profile function (including imaginary and real
parts) are determined directly from the complete pp and p elastic
scattering data at high energies. Full and accurate representation of the data
is presented, with smooth energy dependence of all parameters. The changes
needed in the original profile function required for description of scattering
beyond the forward direction are described.Comment: Latex, 28 pages and 16 figure
Augmentation of nucleon-nucleus scattering by information entropy
Quantum information entropy is calculated from the nucleon nucleus forward
scattering amplitudes. Using a representative set of nuclei, from He to
Pb, and energies, \,[GeV], we establish a linear
dependence of quantum information entropy as functions of logarithm nuclear
mass and logarithm projectile energy .Comment: 5 pages, 2 figure
Microbial imbalance in inflammatory bowel disease patients at different taxonomic levels
Background
Inflammatory bowel disease (IBD), is a debilitating group of chronic diseases including Crohn’s Disease (CD) and ulcerative colitis (UC), which causes inflammation of the gut and affects millions of people worldwide. At different taxonomic levels, the structure of the gut microbiota is significantly altered in IBD patients compared to that of healthy individuals. However, it is unclear how these IBD-affected bacterial groups are related to other common bacteria in the gut, and how they are connected across different disease conditions at the global scale.
Results
In this study, using faecal samples from patients with IBD, we show through diversity analysis of the microbial community structure based on the 16S rRNA gene that the gut microbiome of IBD patients is less diverse compared to healthy individuals. Furthermore, we have identified which bacterial groups change in abundance in both CD and UC compared to healthy controls. A substantial imbalance was observed across four major bacterial phyla including Firmicutes, Bacteroidetes, Proteobacteria and Actinobacteria, which together constitute >98% of the gut microbiota. Next, we reconstructed a bacterial family co-abundance network based on the correlation of abundance profiles obtained from the public gut microbiome data of >22000 samples of faecal and gut biopsies taken from both diseased and healthy individuals. The data was compiled using the EBI metagenomics database [1]. By mapping IBD-altered bacterial families to the network, we show that the bacterial families which exhibit an increased abundance in IBD conditions are not well connected to other groups, implying that these families generally do not coexist together with common gut organisms. Whereas, the bacterial families whose abundance is reduced or did not change in IBD conditions compared to healthy conditions are very well connected to other bacterial groups, suggesting they are highly important groups of bacteria in the gut that can coexist with other bacteria across a range of conditions.
Conclusions
IBD patients exhibited a less diverse gut microbiome compared to healthy individuals. Bacterial groups which changed in IBD patients were found to be groups which do not co-exist well with common commensal gut bacteria, whereas bacterial groups which did not change in patients with IBD were found to commonly co-exist with commensal gut microbiota. This gives a potential insight into the dynamics of the gut microbiota in patients with IBD
Universal Self Force from an Extended-Object Approach
We present a consistent extended-object approach for determining the self
force acting on an accelerating charged particle. In this approach one
considers an extended charged object of finite size , and calculates
the overall contribution of the mutual electromagnetic forces. Previous
implementations of this approach yielded divergent terms
that could not be cured by mass-renormalization. Here we explain the origin of
this problem and fix it. We obtain a consistent, universal, expression for the
extended-object self force, which conforms with Dirac's well known formula.Comment: Latex, one postscript figure, 4 page
Probing nuclear skins and halos with elastic electron scattering
I investigate the elastic electron scattering off nuclei far from the
stability line. The effects of the neutron and proton skins and halos on the
differential cross sections are explored. Examples are given for the charge
distribution in Sn isotopes and its relation to the neutron skin. The neutron
halo in Li and the proton halo in B are also investigated.
Particular interest is paid to the inverse scattering problem and its
dependence on the experimental precision. These studies are of particular
interest for the upcoming electron ion colliders at the GSI and RIKEN
facilities.Comment: 27 pages, 9 figures, accepted for publication in J. Phys.
Implications of area scaling of quantum fluctuations
Quantum fluctuations of a certain class of bulk operators defined in spatial
sub-volumes of Minkowski space-time, have an unexpected area scaling property.
We wish to present evidence that such area scaling may be ascribed to a
boundary theory. We first highlight the implications of area scaling with two
examples in which the boundary area of the spatial regions is not monotonous
with their volume. Next, we prove that the covariance of two operators that are
restricted to two different regions in Minkowski space scales linearly with
their mutual boundary area. Finally, we present an example which demonstrates
why this implies an underlying boundary theory.Comment: 12 pages, 5 figure
Analysis of Independent Roulette Selection in Parallel Ant Colony Optimization
The increased availability of high-performance parallel architectures such as the Graphics Processing Unit (GPU) has led to significant interest in modified versions of metaheuristics that take advantage of their capabilities. Parallel Ant Colony Optimization (ACO) algorithms are now widely-used, but these often present a challenge in terms of maximizing the potential for parallelism. One common bottleneck for parallelization of ACO occurs during the tour construction phase, when edges are probabilistically selected. Independent Roulette (I-Roulette) is an alternative to the standard Roulette Selection method used during this phase, and this achieves significant performance improvements on the GPU. In this paper we provide the first in-depth study of how I-Roulette works. We establish that, even though I-Roulette works in a qualitatively different way to Roulette Wheel selection, its use in two popular ACO variants does not affect the quality of the solutions obtained. However, I-Roulette significantly accelerates convergence to a solution. Our theoretical analysis shows that I-Roulette possesses several interesting and non-obvious features, and is capable of a form of dynamical adaptation during the tour construction process
Analyzing power for the proton elastic scattering from neutron-rich 6He nucleus
Vector analyzing power for the proton-6He elastic scattering at 71
MeV/nucleon has been measured for the first time, with a newly developed
polarized proton solid target working at low magnetic field of 0.09 T. The
results are found to be incompatible with a t-matrix folding model prediction.
Comparisons of the data with g-matrix folding analyses clearly show that the
vector analyzing power is sensitive to the nuclear structure model used in the
reaction analysis. The alpha-core distribution in 6He is suggested to be a
possible key to understand the nuclear structure sensitivity.Comment: 5 pages, 3 figures, accepted for publication as a Rapid Communication
in Physical Review
Effects of Inoculation and Wilting on the Preservation and Utilization of Wheat Forage
Wheat forage was harvested at an early head stage of maturity and ensiled in 12 900-kg experimental silos at three percentages of DM (20.8% for direct-cut forage and 27.9 or 39.3% for wilted forage) either with or without application of a lactic acid bacterial inoculant. The objective was to test the efficacy of the inoculant to alter silage fermentation, preservation, and nutritive value of wheat forage ensiled at different moisture percentages because of wilting. Wilting enhanced DM preservation and decreased fermentation end products. Inoculation made the fermentation more homolactic but did not enhance DM preservation. Silage rations (80% DM as silage) were fed at 1.8% of BW/d to six ruminally and abomasally fistulated steers (350 kg) in an experiment with a Latin-square design and a 3 × 2 factorial arrangement of treatments. Digestive responses to silage diets were not influenced by inoculation. Intake was depressed with direct-cut silage rations. Wilting improved fiber digestibility and was associated with changes in ruminal contents and fermentation end products. Wilting appears to be more effective than inoculation as a postharvest management tool to improve small grain silage. © 1995, American Dairy Science Association. All rights reserved
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