Neutron transition strengths of 21+2^+_1 states in the neutron rich Oxygen isotopes determined from inelastic proton scattering

A coupled-channel analysis of the $^{18,20,22}$O$(p,p')$ data has been performed to determine the neutron transition strengths of 2$^+_1$ states in Oxygen targets, using the microscopic optical potential and inelastic form factor calculated in the folding model. A complex density- and \emph{isospin} dependent version of the CDM3Y6 interaction was constructed, based on the Brueckner-Hatree-Fock calculation of nuclear matter, for the folding model input. Given an accurate isovector density dependence of the CDM3Y6 interaction, the isoscalar ($\delta_0$) and isovector ($\delta_1$) deformation lengths of 2$^+_1$ states in $^{18,20,22}$O have been extracted from the folding model analysis of the $(p,p')$ data. A specific $N$-dependence of $\delta_0$ and $\delta_1$ has been established which can be linked to the neutron shell closure occurring at $N$ approaching 16. The strongest isovector deformation was found for 2$^+_1$ state in $^{20}$O, with $\delta_1$ about 2.5 times larger than $\delta_0$, which indicates a strong core polarization by the valence neutrons in $^{20}$O. The ratios of the neutron/proton transition matrix elements ($M_n/M_p$) determined for 2$^+_1$ states in $^{18,20}$O have been compared to those deduced from the mirror symmetry, using the measured $B(E2)$ values of 2$^+_1$ states in the proton rich $^{18}$Ne and $^{20}$Mg nuclei, to discuss the isospin impurity in the $2^+_1$ excitation of the $A=18,T=1$ and $A=20,T=2$ isobars.Comment: Version accepted for publication in Physical Review

Radiation-reaction-induced evolution of circular orbits of particles around Kerr Black Holes

It is demonstrated that, in the adiabatic approximation, non-Equatorial circular orbits of particles in the Kerr metric (i.e. orbits of constant Boyer-Lindquist radius) remain circular under the influence of gravitational radiation reaction. A brief discussion is given of conditions for breakdown of adiabaticity and of whether slightly non-circular orbits are stable against the growth of eccentricity.Comment: 23 pages. Revtex 3.0. Inquiries to [email protected]

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

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 $^{11}$Li and the proton halo in $^{8}$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.

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 $^4$He to $^{208}$Pb, and energies, $T_{lab} < 1$\,[GeV], we establish a linear dependence of quantum information entropy as functions of logarithm nuclear mass $A$ and logarithm projectile energy $T_{lab}$.Comment: 5 pages, 2 figure

Diffractive Dissociation and Eikonalization in High Energy pp and p pˉ {\bar p} Collisions

We show that eikonal corrections imposed on diffraction dissociation processes calculated in the triple Regge limit, produce a radical change in the energy dependence of the predicted cross section. The induced correction is shown to be in general agreement with the new experimental data measured at the Tevatron.Comment: 11 pages LATEX, ( two figures not included obtainable from authors) (TAUP 2066-93 and FERMILAB PUB 93/ T

Universal Scaling of Optimal Current Distribution in Transportation Networks

Transportation networks are inevitably selected with reference to their global cost which depends on the strengths and the distribution of the embedded currents. We prove that optimal current distributions for a uniformly injected d-dimensional network exhibit robust scale-invariance properties, independently of the particular cost function considered, as long as it is convex. We find that, in the limit of large currents, the distribution decays as a power law with an exponent equal to (2d-1)/(d-1). The current distribution can be exactly calculated in d=2 for all values of the current. Numerical simulations further suggest that the scaling properties remain unchanged for both random injections and by randomizing the convex cost functions.Comment: 5 pages, 5 figure

Asymptotic behaviour of the total cross section of p-p scattering and the Akeno cosmic ray data

I present a new determination of the total cross section for proton-proton collisions from the recent Akeno results on absorption of the cosmic ray protons in the p-Air collisions. Extrapolation to the SSC energy suggests $\sigma_{tot}(p-p) \approx (160-170) mb$. I also comment on a possible sensitivity of the p-Air cross section determinations to assumptions on the inelasticity of nuclear collisions at high energy.Comment: . 6 pages, 0 figure

Computation of Asymptotic Expansions of Turning Point Problems via Cauchy's Integral Formula: Bessel Functions

Linear second-order differential equations having a large real parameter and turning point in the complex plane are considered. Classical asymptotic expansions for solutions involve the Airy function and its derivative, along with two infinite series, the coefficients of which are usually difficult to compute. By considering the series as asymptotic expansions for two explicitly defined analytic functions, Cauchy's integral formula is employed to compute the coefficient functions to a high order of accuracy. The method employs a certain exponential form of Liouville´Green expansions for solutions of the differential equation, as well as for the Airy function. We illustrate the use of the method with the high accuracy computation of Airy-type expansions of Bessel functions of complex argument.The authors acknowledge support from Ministerio de Economía y Competitividad, project MTM2015-67142-P (MINECO/FEDER, UE). A.G. and J.S. acknowledge support from Ministerio de Economía y Competitividad, project MTM2012-34787. A.G. acknowledges the Fulbright/MEC Program for support during her stay at SDSU. J.S. acknowledges the Salvador de Madariaga Program for support during his stay at SDSU

A Transient New Coherent Condition of Matter: The Signal for New Physics in Hadronic Diffractive Scattering

We demonstrate the existence of an anomalous structure in the data on the diffractive elastic scattering of hadrons at high energies and small momentum transfer. We analyze five sets of experimental data on $p(\overline{p})-p$ scattering from five different experiments with colliding beams, ranging from the first-- and second--generation experiments at $\sqrt{s} = 53$ GeV to the most recent experiments at 546 GeV and at 1800 GeV. All of the data sets exhibit a localized anomalous structure in momentum transfer. We represent the anomalous behavior by a phenomenological formula. This is based upon the idea that a transient coherent condition of matter occurs in some of the intermediate inelastic states which give rise, via unitarity, to diffractive elastic scattering. The Fourier--Bessel transform into momentum--transfer space of a spatial oscillatory behavior of matter in the impact--parameter plane results in a small piece of the diffractive amplitude which exhibits a localized anomalous behavior near a definite value of $-t$. In addition, we emphasize possible signals coming directly from such a new condition of matter that may be present in current experiments on inelastic processes.Comment: 25 pages, LaTeX (12 figures, not included). A complete postscript file (except figures 1 and 11, which are available upon request) is available via anonymous ftp at ttpux2.physik.uni-karlsruhe.de (129.13.102.139) as /ttp94-03 /ttp94-03.ps, Local preprint# TTP94-03 (March 1994