Transformation of in-plane ρ(T)\rho (T) in YBa2Cu3O7−δYBa_{2}Cu_{3}O_{7-\delta} at fixed oxygen content

This paper reveals the origin of variation in the magnitude and temperature dependence of the normal state resistivity frequently observed in different YBCO single crystal or thin film samples with the same $T_{c}$. We investigated temperature dependence of resistivity in $YBa_{2}Cu_{3}O_{7-\delta}$ thin films with 7- $\delta = 6.95$ and 6.90, which were subjected to annealing in argon at 400-420 K ($120-140^{o}C$). Before annealing these films exhibited a non-linear $\rho_{ab}(T)$, with a flattening below 230 K, similar to $\rho_{b}(T)$ and $\rho_{ab}(T)$ observed in untwinned and twinned YBCO crystals, respectively. For all films the annealing causes an increase of resistivity and a transformation of $\rho_{ab}(T)$ from a non-linear dependence towards a more linear one (less flattening). In films with 7- $\delta = 6.90$ the increase of resistivity is also associated with an increase in $T_{c}$. We proposed the model that provides an explanation of these phenomena in terms of thermally activated redistribution of residual O(5) oxygens in the chain-layer of YBCO. Good agreement between the experimental data for $\rho_{ab}(t,T)$, where t is the annealing time, and numerical calculations was obtained.Comment: 8 pages, 9 figures, submitted to PR

Two-dimensional one-component plasma on a Flamm's paraboloid

We study the classical non-relativistic two-dimensional one-component plasma at Coulomb coupling Gamma=2 on the Riemannian surface known as Flamm's paraboloid which is obtained from the spatial part of the Schwarzschild metric. At this special value of the coupling constant, the statistical mechanics of the system are exactly solvable analytically. The Helmholtz free energy asymptotic expansion for the large system has been found. The density of the plasma, in the thermodynamic limit, has been carefully studied in various situations

Unconstrained Hamiltonian Formulation of SU(2) Gluodynamics

SU(2) Yang-Mills field theory is considered in the framework of the generalized Hamiltonian approach and the equivalent unconstrained system is obtained using the method of Hamiltonian reduction. A canonical transformation to a set of adapted coordinates is performed in terms of which the Abelianization of the Gauss law constraints reduces to an algebraic operation and the pure gauge degrees of freedom drop out from the Hamiltonian after projection onto the constraint shell. For the remaining gauge invariant fields two representations are introduced where the three fields which transform as scalars under spatial rotations are separated from the three rotational fields. An effective low energy nonlinear sigma model type Lagrangian is derived which out of the six physical fields involves only one of the three scalar fields and two rotational fields summarized in a unit vector. Its possible relation to the effective Lagrangian proposed recently by Faddeev and Niemi is discussed. Finally the unconstrained analog of the well-known nonnormalizable groundstate wave functional which solves the Schr\"odinger equation with zero energy is given and analysed in the strong coupling limit.Comment: 20 pages REVTEX, no figures; final version to appear in Phys. Rev. D; minor changes, notations simplifie

Linear response function around a localized impurity in a superconductor

Imaging the effects of an impurity like Zn in high-Tc superconductors [Nature 61 (2000) 746] has rekindled interest in defect problems in the superconducting phase. This has prompted us here to re-examine the early work of March and Murray [Phys. Rev. 120 (1960) 830] on the linear response function in an initially translationally invariant Fermi gas. In particular, we present corresponding results for a superconductor at zero temperature, both in the s- and in the d-wave case, and mention their direct physical relevance in the case when the impurity potential is highly localized

Impact of Obesity on Disease Activity and Patient-Reported Outcomes Measurement Information System (PROMIS) in Inflammatory Bowel Diseases

INTRODUCTION:We conducted a cohort study on the impact of obesity on disease activity and Patient-Reported Outcomes Measurement Information System (PROMIS) measures in the inflammatory bowel disease (IBD) Partners cohort.METHODS:We performed a cross-sectional and longitudinal study within IBD Partners, an internet-based cohort of >15,000 patients living with Crohn's disease (CD) and ulcerative colitis (UC). We included adult patients with IBD, with recorded body mass index (BMI), with at least 6 months of follow-up, excluding patients with BMI < 18.5 kg/m2. We evaluated the independent effect of World Health Organization classes of obesity on risk of clinical relapse or persistent disease activity (using validated disease activity indexes) and PROMIS measures, using multivariate logistic regression and linear regression, respectively.RESULTS:We included 7,296 patients with IBD (4,748 patients with CD, 19.5% obese; 2,548 patients with UC with intact colon, 20.3% obese). Obesity was independently, and in a dose-dependent fashion, associated with an increased risk of persistent disease activity or relapse in both patients with CD (class II or III obesity vs normal BMI: adjusted odds ratio, 1.86; 95% confidence interval, 1.30-2.68) and UC (adjusted odds ratio, 2.97; 95% confidence interval, 1.75-5.17). Obesity was also independently associated with higher anxiety, depression, fatigue, pain, and inferior social function scores in patients with CD and UC at baseline and with worsening depression, fatigue, pain, and social function in patients with CD on longitudinal assessment.DISCUSSION:Obesity at baseline is independently associated with worsening disease activity and PROMIS measures in patients with IBD

Atomic diffraction from nanostructured optical potentials

We develop a versatile theoretical approach to the study of cold-atom diffractive scattering from light-field gratings by combining calculations of the optical near-field, generated by evanescent waves close to the surface of periodic nanostructured arrays, together with advanced atom wavepacket propagation on this optical potential.Comment: 8 figures, 10 pages, submitted to Phys. Rev.

An estimate of the flavour singlet contributions to the hyperfine splitting in charmonium

We explore the splitting between flavour singlet and non-singlet mesons in charmonium. This has implications for the hyperfine splitting in charmonium

GPDs of the nucleons and elastic scattering at high energies

Taking into account the electromagnetic and gravitational form factors, calculated from a new set of $t$-dependent GPDs, a new model is built. The real part of the hadronic amplitude is determined only through complex $s$. In the framework of this model the quantitative description of all existing experimental data at $52.8 \leq \sqrt{s} \leq 1960 \$GeV, including the Coulomb range and large momentum transfers ($0.0008 \leq |t| \leq 9.75 \ $GeV$^2$), is obtained with only$3$fitting high energy parameters. The comparison with the preliminary data of the TOTEM Collaboration at an energy of$7$ TeV is made.Comment: 14 pages, 21 figures, minor corrections (slightly brush English and removed two misprint in numbering

Comparing benefits from many possible computed tomography lung cancer screening programs: Extrapolating from the National Lung Screening Trial using comparative modeling

Background: The National Lung Screening Trial (NLST) demonstrated that in current and former smokers aged 55 to 74 years, with at least 30 pack-years of cigarette smoking history and who had quit smoking no more than 15 years ago, 3 annual computed tomography (CT) screens reduced lung cancer-specific mortality by 20% relative to 3 annual chest X-ray screens. We compared the benefits achievable with 576 lung cancer screening programs that varied CT screen number and frequency, ages of screening, and eligibility based on smoking. Methods and Findings: We used five independent microsimulation models with lung cancer natural history parameters previously calibrated to the NLST to simulate life histories of the US cohort born in 1950 under all 576 programs. 'Efficient' (within model) programs prevented the greatest number of lung cancer deaths, compared to no screening, for a given number of CT screens. Among 120 'consensus efficient' (identified as efficient across models) programs, the average starting age was 55 years, the stopping age was 80 or 85 years, the average minimum pack-years was 27, and the maximum years since quitting was 20. Among consensus efficient programs, 11% to 40% of the cohort was screened, and 153 to 846 lung cancer deaths were averted per 100,000 people. In all models, annual screening based on age and smoking eligibility in NLST was not efficient; continuing screening to age 80 or 85 years was more efficient. Conclusions: Consensus results from five models identified a set of efficient screening programs that include annual CT lung cancer screening using criteria like NLST eligibility but extended to older ages. Guidelines for screening should also consider harms of screening and individual patient characteristics

D* Production in Deep Inelastic Scattering at HERA

This paper presents measurements of D^{*\pm} production in deep inelastic scattering from collisions between 27.5 GeV positrons and 820 GeV protons. The data have been taken with the ZEUS detector at HERA. The decay channel $D^{*+}\to (D^0 \to K^- \pi^+) \pi^+$ (+ c.c.) has been used in the study. The $e^+p$ cross section for inclusive D^{*\pm} production with $5<Q^2<100 GeV^2$ and $y<0.7$ is 5.3 \pms 1.0 \pms 0.8 nb in the kinematic region {$1.3<p_T(D^{*\pm})<9.0$ GeV and $| \eta(D^{*\pm}) |<1.5$}. Differential cross sections as functions of p_T(D^{*\pm}), $\eta(D^{*\pm}), W$ and $Q^2$ are compared with next-to-leading order QCD calculations based on the photon-gluon fusion production mechanism. After an extrapolation of the cross section to the full kinematic region in p_T(D^{*\pm}) and $\eta$(D^{*\pm}), the charm contribution $F_2^{c\bar{c}}(x,Q^2)$ to the proton structure function is determined for Bjorken $x$ between 2 $\cdot$ 10$^{-4}$ and 5 $\cdot$ 10$^{-3}$.Comment: 17 pages including 4 figure