2,815 research outputs found

    Influence of higher d-wave gap harmonics on the dynamical magnetic susceptibility of high-temperature superconductors

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    Using a fermiology approach to the computation of the magnetic susceptibility measured by neutron scattering in hole-doped high-Tc superconductors, we estimate the effects on the incommensurate peaks caused by higher d-wave harmonics of the superconducting order parameter induced by underdoping. The input parameters for the Fermi surface and d-wave gap are taken directly from angle resolved photoemission (ARPES) experiments on Bi{2}Sr{2}CaCu{2}O{8+x} (Bi2212). We find that higher d-wave harmonics lower the momentum dependent spin gap at the incommensurate peaks as measured by the lowest spectral edge of the imaginary part in the frequency dependence of the magnetic susceptibility of Bi2212. This effect is robust whenever the fermiology approach captures the physics of high-Tc superconductors. At energies above the resonance we observe diagonal incommensurate peaks. We show that the crossover from parallel incommensuration below the resonance energy to diagonal incommensuration above it is connected to the values and the degeneracies of the minima of the 2-particle energy continuum.Comment: 13 pages, 7 figure

    In My View

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    Imaging Findings in Two Cases of Fluoroquinolone-Induced Achilles Tendinopathy

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    AbstractTendonitis and tendon rupture are rare but recognized complications of fluoroquinolone therapy. Most reports of this problem have appeared in the rheumatology and pharmacology literature, and this topic has received little attention in the radiologic literature. We report two cases of fluoroquinolone-induced tendinopathy and describe their magnetic resonance (MR) and sonographic findings. Although Achilles tendinopathy is generally the result of repetitive injury, it is useful to keep other causes in mind. MR or sonographic findings of Achilles tendinopathy in a patient without history of antecedent trauma should prompt the radiologist to consider fluoroquinolone treatment as a possible causative agent

    Analysis and Prediction of Telephone Demand in Local Geographic Areas

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    An approach to forecasting the demand or local area telephone service is presented in this paper. The specific problem discussed is the fore­ casting of main stations in three Michigan metropolitan areas. Several different statistical models are used. The first class of models introduced uses adaptive exponential smoothing and is based solely on the past history of the time series involved. Although appropriate data at the local area level are very difficult to obtain, two exogenous time series related to household formations are used to construct more elaborate models for one of the areas. The various models are evaluated by both the average absolute and the root-mean-square forecast error. In terms of these criteria, the first class of models referred to above performs reasonably well while the second set does considerably better. This argues strongly that future improvements in forecasting accuracy will be made by the more extensive involvement of exogenous variables

    Aggregate Versus Subaggregate Models in Local Area Forecasting

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    Should statistical forecasts be constructed by aggregating data to each level for which forecasts are required or aggregating the forecasts from the lower levels? The relevant literature suggest no general answer. In this study using actual data, forecasts aggregated form lower-level forecasts were found best

    Ambiguities in the Cross-Section Analysis of Per Share Financial Data

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    In analyzing corporate financial data it is standard procedure to adjust the data to reflect the current number of shares outstanding. In this study, we show that this simple ,standard procedure can cause serious difficulties in a financial analysis

    Modules for Experiments in Stellar Astrophysics (MESA): Giant Planets, Oscillations, Rotation, and Massive Stars

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    We substantially update the capabilities of the open source software package Modules for Experiments in Stellar Astrophysics (MESA), and its one-dimensional stellar evolution module, MESA Star. Improvements in MESA Star's ability to model the evolution of giant planets now extends its applicability down to masses as low as one-tenth that of Jupiter. The dramatic improvement in asteroseismology enabled by the space-based Kepler and CoRoT missions motivates our full coupling of the ADIPLS adiabatic pulsation code with MESA Star. This also motivates a numerical recasting of the Ledoux criterion that is more easily implemented when many nuclei are present at non-negligible abundances. This impacts the way in which MESA Star calculates semi-convective and thermohaline mixing. We exhibit the evolution of 3-8 Msun stars through the end of core He burning, the onset of He thermal pulses, and arrival on the white dwarf cooling sequence. We implement diffusion of angular momentum and chemical abundances that enable calculations of rotating-star models, which we compare thoroughly with earlier work. We introduce a new treatment of radiation-dominated envelopes that allows the uninterrupted evolution of massive stars to core collapse. This enables the generation of new sets of supernovae, long gamma-ray burst, and pair-instability progenitor models. We substantially modify the way in which MESA Star solves the fully coupled stellar structure and composition equations, and we show how this has improved MESA's performance scaling on multi-core processors. Updates to the modules for equation of state, opacity, nuclear reaction rates, and atmospheric boundary conditions are also provided. We describe the MESA Software Development Kit (SDK) that packages all the required components needed to form a unified and maintained build environment for MESA. [Abridged]Comment: Accepted for publication in The ApJ Supplement Series. Extra informations required to reproduce the calculations in this paper are available at http://mesastar.org/results/mesa

    Inhibition of NF-κB Activation In Vivo Impairs Establishment of Gammaherpesvirus Latency

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    A critical determinant in chronic gammaherpesvirus infections is the ability of these viruses to establish latency in a lymphocyte reservoir. The nuclear factor (NF)-κB family of transcription factors represent key players in B-cell biology and are targeted by gammaherpesviruses to promote host cell survival, proliferation, and transformation. However, the role of NF-κB signaling in the establishment of latency in vivo has not been addressed. Here we report the generation and in vivo characterization of a recombinant murine gammaherpesvirus 68 (γHV68) that expresses a constitutively active form of the NF-κB inhibitor, IκBαM. Inhibition of NF-κB signaling upon infection with γHV68-IκBαM did not affect lytic replication in cell culture or in the lung following intranasal inoculation. However, there was a substantial decrease in the frequency of latently infected lymphocytes in the lung (90% reduction) and spleens (97% reduction) 16 d post intranasal inoculation. Importantly, the defect in establishment of latency in lung B cells could not be overcome by increasing the dose of virus 100-fold. The observed decrease in establishment of viral latency correlated with a loss of activated, CD69(hi) B cells in both the lungs and spleen at day 16 postinfection, which was not apparent by 6 wk postinfection. Constitutive expression of Bcl-2 in B cells did not rescue the defect in the establishment of latency observed with γHV68-IκBαM, indicating that NF-κB–mediated functions apart from Bcl-2–mediated B-cell survival are critical for the efficient establishment of gammaherpesvirus latency in vivo. In contrast to the results obtained following intranasal inoculation, infection of mice with γHV68-IκBαM by the intraperitoneal route had only a modest impact on splenic latency, suggesting that route of inoculation may alter requirements for establishment of virus latency in B cells. Finally, analyses of the pathogenesis of γHV68-IκBαM provides evidence that NF-κB signaling plays an important role during multiple stages of γHV68 infection in vivo and, as such, represents a key host regulatory pathway that is likely manipulated by the virus to establish latency in B cells

    Puente Petaluma, California

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    Otros cuatro tramos están formados de vigas prefabricadas de hormigón armado, de 7,60 m de longitud, que junto con sus soportes de cuatro columnas constituyen una especie de torre. El tramo sobre el canal tiene 49 m de luz; y sus vigas son metálicas, formadas con chapa y perfiles
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