256 research outputs found

    Representations of reductive normal algebraic monoids

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    The rational representation theory of a reductive normal algebraic monoid (with one-dimensional center) forms a highest weight category, in the sense of Cline, Parshall, and Scott. This is a fundamental fact about the representation theory of reductive normal algebraic monoids. We survey how this result was obtained, and treat some natural examples coming from classical groups.Comment: 10 pages. To appear in a volume of the Fields Communications Series: "Algebraic Monoids, Group Embeddings, and Algebraic Combinatorics," edited by Mahir Can, Zhenheng Li, Benjamin Steinberg, and Qiang Wan

    Effect of risedronate on joint structure and symptoms of knee osteoarthritis: results of the BRISK randomized, controlled trial [ISRCTN01928173]

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    To determine the efficacy and safety of risedronate in patients with knee osteoarthritis (OA), the British study of risedronate in structure and symptoms of knee OA (BRISK), a 1-year prospective, double-blind, placebo-controlled study, enrolled patients (40–80 years of age) with mild to moderate OA of the medial compartment of the knee. The primary aims were to detect differences in symptoms and function. Patients were randomized to once-daily risedronate (5 mg or 15 mg) or placebo. Radiographs were taken at baseline and 1 year for assessment of joint-space width using a standardized radiographic method with fluoroscopic positioning of the joint. Pain, function, and stiffness were assessed using the Western Ontario and McMaster Universities (WOMAC) OA index. The patient global assessment and use of walking aids were measured and bone and cartilage markers were assessed. The intention-to-treat population consisted of 284 patients. Those receiving risedronate at 15 mg showed improvement of the WOMAC index, particularly of physical function, significant improvement of the patient global assessment (P < 0.001), and decreased use of walking aids relative to patients receiving the placebo (P = 0.009). A trend towards attenuation of joint-space narrowing was observed in the group receiving 15 mg risedronate. Eight percent (n = 7) of patients receiving placebo and 4% (n = 4) of patients receiving 5 mg risedronate exhibited detectable progression of disease (joint-space width ≥ 25% or ≥ 0.75 mm) versus 1% (n = 1) of patients receiving 15 mg risedronate (P = 0.067). Risedronate (15 mg) significantly reduced markers of cartilage degradation and bone resorption. Both doses of risedronate were well tolerated. In this study, clear trends towards improvement were observed in both joint structure and symptoms in patients with primary knee OA treated with risedronate

    Self-consistent anisotropic oscillator with cranked angular and vortex velocities

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    The Kelvin circulation is the kinematical Hermitian observable that measures the true character of nuclear rotation. For the anisotropic oscillator, mean field solutions with fixed angular momentum and Kelvin circulation are derived in analytic form. The cranking Lagrange multipliers corresponding to the two constraints are the angular and vortex velocities. Self-consistent solutions are reported with a constraint to constant volume.Comment: 12 pages, LaTex/RevTex, Phys. Rev. C4

    Interruption of the Arterial Inferior Alveolar Flow and its Effects on Mandibular Collateral Circulation and Dental Tissues

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    The interruption of circulation through the inferior alveolar artery was followed by the establishment of a fast retrograde blood flow through the vessel. The mental artery and the mandibular branch of the sublingual artery were the main vessels to contribute to that flow. No histopathologic changes were found in the experimental hemimandibles; however, temporary regressive changes were found in the dental pulps of molars.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67920/2/10.1177_00220345750540040301.pd

    Ultra-cold atoms in an optical cavity: two-mode laser locking to the cavity avoiding radiation pressure

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    The combination of ultra-cold atomic clouds with the light fields of optical cavities provides a powerful model system for the development of new types of laser cooling and for studying cooperative phenomena. These experiments critically depend on the precise tuning of an incident pump laser with respect to a cavity resonance. Here, we present a simple and reliable experimental tuning scheme based on a two-mode laser spectrometer. The scheme uses a first laser for probing higher-order transversal modes of the cavity having an intensity minimum near the cavity's optical axis, where the atoms are confined by a magnetic trap. In this way the cavity resonance is observed without exposing the atoms to unwanted radiation pressure. A second laser, which is phase-locked to the first one and tuned close to a fundamental cavity mode drives the coherent atom-field dynamics.Comment: 7 pages, 7 figure

    Stable, Time-Dependent, Exact Solutions for Brane Models with a Bulk Scalar Field

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    We derive two classes of brane-world solutions arising in the presence of a bulk scalar field. For static field configurations, we adopt a time-dependent, factorizable metric ansatz that allows for radion stabilization. The solutions are characterized by a non-trivial warping along the extra dimension, even in the case of a vanishing bulk cosmological constant, and lead to a variety of inflationary, time-dependent solutions of the 3D scale factor on the brane. We also derive the constraints necessary for the stability of these solutions under time-dependent perturbations of the radion field, and we demonstrate the existence of phenomenologically interesting, stable solutions with a positive cosmological constant on the brane.Comment: 24 pages, latex, 4 eps figur

    The role of ν\nu-induced reactions on lead and iron in neutrino detectors

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    We have calculated cross sections and branching ratios for neutrino induced reactions on ^{208}Pb and ^{56}Fe for various supernova and accelerator-relevant neutrino spectra. This was motivated by the facts that lead and iron will be used on one hand as target materials in future neutrino detectors, on the other hand have been and are still used as shielding materials in accelerator-based experiments. In particular we study the inclusive ^{56}Fe(νe,e)Fe(\nu_e,e^-)^{56}Co and ^{208}Pb(νe,e)Pb(\nu_e,e^-)^{208}Bi cross sections and calculate the neutron energy spectra following the decay of the daughter nuclei. These reactions give a potential background signal in the KARMEN and LSND experiment and are discussed as a detection scheme for supernova neutrinos in the proposed OMNIS and LAND detectors. We also study the neutron-emission following the neutrino-induced neutral-current excitation of ^{56}Fe and ^{208}Pb.Comment: 23 pages (including 7 figures

    A guanosine 5′-triphosphate-dependent protein kinase is localized in the outer envelope membrane of pea chloroplasts

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    A guanosine 5-triphosphate (GTP)-dependent protein kinase was detected in preparations of outer chloroplast envelope membranes of pea (Pisum sativum L.) chloroplasts. The protein-kinase activity was capable of phosphorylating several envelope-membrane proteins. The major phosphorylated products were 23- and 32.5-kilo-dalton proteins of the outer envelope membrane. Several other envelope proteins were labeled to a lesser extent. Following acid hydrolysis of the labeled proteins, most of the label was detected as phosphoserine with only minor amounts detected as phosphothreonine. Several criteria were used to distinguish the GTP-dependent protein kinase from an ATP-dependent kinase also present in the outer envelope membrane. The ATP-dependent kinase phosphorylated a very different set of envelope-membrane proteins. Heparin inhibited the GTP-dependent kinase but had little effect upon the ATP-dependent enzyme. The GTP-dependent enzyme accepted phosvitin as an external protein substrate whereas the ATP-dependent enzyme did not. The outer membrane of the chloroplast envelope also contained a phosphotransferase capable of transferring labeled phosphate from [-32P]GTP to ADP to yield (-32P]ATP. Consequently, addition of ADP to a GTP-dependent protein-kinase assay resulted in a switch in the pattern of labeled products from that seen with GTP to that typically seen with ATP

    Brane Cosmology in the Background of D-Brane with NS B Field

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    We study the cosmological evolution of the four-dimensional universe on the probe D3-brane in geodesic motion in the curved background of the source Dp-brane with non-zero NS B field. The Friedman equations describing the expansion of the brane universe are obtained and analyzed for various limits. We elaborate on corrections to the cosmological evolution due to nonzero NS B field.Comment: 13 pages, LaTeX, revised version with minor corrections to appear in Phys. Rev.

    Cosmology of Brane Models with Radion Stabilization

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    We analyze the cosmology of the Randall-Sundrum model and that of compact brane models in general in the presence of a radius stabilization mechanism. We find that the expansion of our universe is generically in agreement with the expected effective four dimensional description. The constraint (which is responsible for the appearance of non-conventional cosmologies in these models) that must be imposed on the matter densities on the two branes in the theory without a stabilized radius is a consequence of requiring a static solution even in the absence of stabilization. Such constraints disappear in the presence of a stablizing potential, and the ordinary FRW (Friedmann-Robertson-Walker) equations are reproduced, with the expansion driven by the sum of the physical values of the energy densities on the two branes and in the bulk. For the case of the Randall-Sundrum model we examine the kinematics of the radion field, and find that corrections to the standard FRW equations are small for temperatures below the weak scale. We find that the radion field has renormalizable and unsuppressed couplings to Standard Model particles after electroweak symmetry breaking. These couplings may have important implications for collider searches. We comment on the possibility that matter off the TeV brane could serve as a dark matter candidate.Comment: 35 pages, Late
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