540 research outputs found

    Crystal Structure and Physical Properties of U3T3Sn4 (T = Ni, Cu) Single-Crystals

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    Heat capacity experiments, crystal structure determination and transmission electron microscopy have been carried out on U3Cu3Sn4 single-crystals. U3Cu3Sn4 was confirmed to be a heavy-fermion antiferromagnet (TN=13(1) K) with a low temperature electronic heat capacity coefficient gamma=390 mJ/molUK2. Low temperature heat capacity experiments on a U3Ni3Sn4 single-crystal indicate that below 0.4 K there is a crossover between the previously observed non-Fermi liquid behavior and a Fermi liquid state.Comment: 12 pages (incl. 2 tables & 4 figures), to appear in Physica

    Inflammatory Bowel Disease is Similar in Patients with Older Onset and Younger Onset

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    Background: As the American population is aging, the number of older people with inflammatory bowel disease is increasing. We used clinical data from the Sinai-Helmsley Alliance for Research Excellence (SHARE), a prospective cohort, to examine disease and treatment differences in older adults. Methods: We performed a cross-sectional study assessing demographics and disease behavior by age at diagnosis with univariate, bivariate, and multivariate analyses. "Older-onset" patients were diagnosed after age 60, "younger-onset" patients were diagnosed before age 60 but are older than 60 years, and the remainder were "young." Results: There were 91 older-onset, 389 younger-onset, and 3431 young patients with Crohn's disease. Older-onset patients had more ileal (37%) and colonic (27%) disease compared with younger-onset and young patients. There were no differences in disease behavior, location, or surgeries between older-onset and young patients with Crohn's disease within 5 years of diagnosis. Older-onset patients with inflammatory disease had a higher odds of being in remission. Young patients reported more anti-tumor necrosis factor and thiopurine use compared with younger-onset and older-onset patients (P < 0.01). There were 98 older-onset, 218 younger-onset, and 1702 young patients with ulcerative colitis. There were no differences in disease extent, activity index, or surgeries. Young patients with ulcerative colitis reported more anti-tumor necrosis factor use (26%) compared with younger-onset patients (17%, P < 0.01). Conclusions: Disease behavior or location was not different between younger and older adults with inflammatory bowel disease. Older patients were less likely to be treated with immunosuppression. If older patients have similar disease behavior, less frequent treatment with immunosuppressives may risk suboptimally controlled disease

    Depression is associated with more aggressive inflammatory bowel disease

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    OBJECTIVES: Depression is prevalent in inflammatory bowel disease (IBD) patients. The impact of depression on IBD is not well-studied. It is unknown how providers should assess depression. METHODS: We used data from the Sinai-Helmsley Alliance for Research Excellence cohort, to assess methods of diagnosing depression and effects of baseline depression on disease activity at follow-up. A patient health questionnaire (PHQ-8) score ≥5 was consistent with mild depression. Relapse was defined as a modified Harvey-Bradshaw Index ≥5 or Simple Clinical Colitis Activity Index >2. We performed binomial regression to calculate adjusted risk ratios (RRs). RESULTS: We included 2,798 Crohn's disease (CD) patients with 22-month mean follow-up and 1,516 ulcerative colitis (UC) patients with 24-month mean follow-up. A total of 64% of CD patients and 45% of UC patients were in remission at baseline. By self-report, 20% of CD and 14% of UC patients were depressed. By PHQ-8, 38% of CD and 32% of UC patients were depressed ( P <0.01). Adjusted for sex, remission, and disease activity, CD patients with baseline depression were at an increased risk for relapse (RR: 2.3; 95% confidence interval (CI): 1.9-2.8), surgery, or hospitalization (RR: 1.3 95% CI: 1.1-1.6) at follow-up. UC patients with baseline depression were also at increased risk for relapse (RR: 1.3; 95% CI: 0.9-1.7), surgery, or hospitalization (RR: 1.3; 95% CI: 1.1-1.5) at follow-up. CONCLUSIONS: Baseline depression is associated with a higher risk for aggressive IBD at follow-up. A single question is not a sensitive method of assessing depression. Providers should consider administering the PHQ-8 to capture those at greater risk for aggressive disease

    Colossal dielectric constants in transition-metal oxides

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    Many transition-metal oxides show very large ("colossal") magnitudes of the dielectric constant and thus have immense potential for applications in modern microelectronics and for the development of new capacitance-based energy-storage devices. In the present work, we thoroughly discuss the mechanisms that can lead to colossal values of the dielectric constant, especially emphasising effects generated by external and internal interfaces, including electronic phase separation. In addition, we provide a detailed overview and discussion of the dielectric properties of CaCu3Ti4O12 and related systems, which is today's most investigated material with colossal dielectric constant. Also a variety of further transition-metal oxides with large dielectric constants are treated in detail, among them the system La2-xSrxNiO4 where electronic phase separation may play a role in the generation of a colossal dielectric constant.Comment: 31 pages, 18 figures, submitted to Eur. Phys. J. for publication in the Special Topics volume "Cooperative Phenomena in Solids: Metal-Insulator Transitions and Ordering of Microscopic Degrees of Freedom

    Time-Dependent CP Violation Effects in Partially Reconstructed B0DπB^0 \to D^* \pi Decays

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    We report measurements of time-dependent decay rates for B0Dπ±B^0 \to D^{*\mp} \pi^\pm decays and extraction of CP violation parameters related to ϕ3\phi_3. We use a partial reconstruction technique, whereby signal events are identified using information only from the primary pion and the charged pion from the decay of the DD^{*\mp}. The analysis uses 140fb1140 {\rm fb}^{-1} of data accumulated at the Υ(4S)\Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+ee^{+}e^{-} collider. We measure the CP violation parameters S+=0.035±0.041(stat)±0.018(syst)S^+ = 0.035 \pm 0.041 ({\rm stat}) \pm 0.018 ({\rm syst}) and S=0.025±0.041(stat)±0.018(syst)S^- = 0.025 \pm 0.041 ({\rm stat}) \pm 0.018 ({\rm syst}).Comment: 15 pages, 5 figures. To appear in Physics Letters

    D* Production in Deep Inelastic Scattering at HERA

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    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+(D0Kπ+)π+D^{*+}\to (D^0 \to K^- \pi^+) \pi^+ (+ c.c.) has been used in the study. The e+pe^+p cross section for inclusive D^{*\pm} production with 5<Q2<100GeV25<Q^2<100 GeV^2 and y<0.7y<0.7 is 5.3 \pms 1.0 \pms 0.8 nb in the kinematic region {1.3<pT(D±)<9.01.3<p_T(D^{*\pm})<9.0 GeV and η(D±)<1.5| \eta(D^{*\pm}) |<1.5}. Differential cross sections as functions of p_T(D^{*\pm}), η(D±),W\eta(D^{*\pm}), W and Q2Q^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 η\eta(D^{*\pm}), the charm contribution F2ccˉ(x,Q2)F_2^{c\bar{c}}(x,Q^2) to the proton structure function is determined for Bjorken xx between 2 \cdot 104^{-4} and 5 \cdot 103^{-3}.Comment: 17 pages including 4 figure

    Observation of Scaling Violations in Scaled Momentum Distributions at HERA

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    Charged particle production has been measured in deep inelastic scattering (DIS) events over a large range of xx and Q2Q^2 using the ZEUS detector. The evolution of the scaled momentum, xpx_p, with Q2,Q^2, in the range 10 to 1280 GeV2GeV^2, has been investigated in the current fragmentation region of the Breit frame. The results show clear evidence, in a single experiment, for scaling violations in scaled momenta as a function of Q2Q^2.Comment: 21 pages including 4 figures, to be published in Physics Letters B. Two references adde

    Observation of hard scattering in photoproduction events with a large rapidity gap at HERA

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    Events with a large rapidity gap and total transverse energy greater than 5 GeV have been observed in quasi-real photoproduction at HERA with the ZEUS detector. The distribution of these events as a function of the γp\gamma p centre of mass energy is consistent with diffractive scattering. For total transverse energies above 12 GeV, the hadronic final states show predominantly a two-jet structure with each jet having a transverse energy greater than 4 GeV. For the two-jet events, little energy flow is found outside the jets. This observation is consistent with the hard scattering of a quasi-real photon with a colourless object in the proton.Comment: 19 pages, latex, 4 figures appended as uuencoded fil
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