4,248 research outputs found

    Operator product expansions as a consequence of phase space properties

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    The paper presents a model-independent, nonperturbative proof of operator product expansions in quantum field theory. As an input, a recently proposed phase space condition is used that allows a precise description of point field structures. Based on the product expansions, we also define and analyze normal products (in the sense of Zimmermann).Comment: v3: minor wording changes, as to appear in J. Math. Phys.; 12 page

    Through a Different Lens: A Reply to Stephan Thernstrom.

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    Improvement of a Dumped Rockfill Foundation by Dynamic Consolidation

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    The paper describes an Industrial Park development, on the British Columbia coast, where Dynamic Consolidation was chosen to densify a loose rockfill prior to construction of a modern high capacity sawmill on shallow foundations. The design and execution of the compaction are described. The in situ tests used to monitor the compaction are described and results presented. It is concluded that the desired result was achieved, and this is supported by a survey of foundation elevations taken four years after construction

    Lowering Somatic Cell Count with Best Management Practices

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    As health and food safety concerns grow, dairy producers are facing more stringent regulations. In 2010, the European Union (EU) set the somatic cell count (SCC) upper limit, an indicator of milk quality, for exported milk at 400,000 cells per milliliter. However, the current U.S. SCC limit is 750,000 cells per milliliter. As of January 2012, any U.S. milk used in export markets must meet the EU standards. It is projected that US milk processors will gradually adopt the EU upper limit, making it difficult for dairy producers to sell milk containing more than 400,000 somatic cells per milliliter. Dairy producers will have to find innovative and cost-effective ways to reduce the somatic cell count of their milk. This publication will discuss how agriculture best management practices can be used to lower SCC

    Surface characterization of selected LDEF tray clamps

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    The surface characterization of chromic acid anodized 6061-T6 aluminum alloy tray clamps has shown differences in surface chemistry depending upon the position on the Long Duration Exposure Facility (LDEF). Water contact angle results showed no changes in wettability of the tray clamps. The overall surface topography of the control, trailing edge(E3) and leading edge(D9) samples was similar. The thickness of the aluminum oxide layer for all samples determined by Auger depth profiling was less than one micron. X-ray photoelectron spectroscopy (XPS) analysis of the tray clamps showed significant differences in the surface composition. Carbon and silicon containing compounds were the primary contaminants detected

    Gründung eines Heimatvereins in Londorf

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    Recent cases of successful control of human immunodeficiency virus (HIV) by bone marrow transplant in combination with suppressive antiretroviral therapy (ART) and very early initiation of ART have provided proof of concept that HIV infection might now be cured. Current efforts focusing on gene therapy, boosting HIV-specific immunity, reducing inflammation and activation of latency have all been the subject of recent excellent reviews. We now propose an additional avenue of research towards a cure for HIV: targeting HIV apoptosis regulatory pathways. The central enigma of HIV disease is that HIV infection kills most of the CD4 T cells that it infects, but those cells that are spared subsequently become a latent reservoir for HIV against which current medications are ineffective. We propose that if strategies could be devised which would favor the death of all cells which HIV infects, or if all latently infected cells that release HIV would succumb to viral-induced cytotoxicity, then these approaches combined with effective ART to prevent spreading infection, would together result in a cure for HIV. This premise is supported by observations in other viral systems where the relationship between productive infection, apoptosis resistance, and the development of latency or persistence has been established. Therefore we propose that research focused at understanding the mechanisms by which HIV induces apoptosis of infected cells, and ways that some cells escape the pro-apoptotic effects of productive HIV infection are critical to devising novel and rational approaches to cure HIV infection

    Mathematical structure of the temporal gauge

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    The mathematical structure of the temporal gauge of QED is critically examined in both the alternative formulations characterized by either positivity or regularity of the Weyl algebra. The conflict between time translation invariance and Gauss law constraint is shown to lead to peculiar features. In the positive case only the correlations of exponentials of fields exist (non regularity), the space translations are not strongly continuous, so that their generators do not exist, a theta vacuum degeneracy occurs, associated to a spontaneous symmetry breaking. In the indefinite case the spectral condition only holds in terms of positivity of the energy, gauge invariant theta-vacua exist on the observables, with no extension to time translation invariant states on the field algebra, the vacuum is faithful on the longitudinal algebra and a KMS structure emerges. Functional integral representations are derived in both cases, with the alternative between ergodic measures on real random fields or complex Gaussian random fields.Comment: Late

    Contrast enhanced computed tomography findings in 105 horse distal extremities

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    The poor soft tissue conspicuity of CT can be improved by using intra-arterial CT Angiography (CTA), and intra-articular and intra-bursal contrast enhanced CT (CTAR). This retrospective study describes a combination protocol of CT and CTA of the horse's foot, and CTAR of the distal interphalangeal joint and navicular bursa. It is hypothesized this would provide a comprehensive overview of the range and severity of distal limb pathology. Radiology reports of all horses admitted for distal limb CT over a 5 year period were reviewed. All horses with a complete four stage CT examination and radiology report with lameness isolated to the foot were included. Twenty seven imaging findings using a four grade semiquantitative severity scoring system contributing towards six main diagnostic categories were described. One hundred and five examinations on 56 horses revealed a diagnosis of navicular bone disease in 64%, deep digital flexor tendinopathy in 43%, distal interphalangeal osteoarthritis in 35%, navicular bursitis in 31%, distal interphalangeal collateral ligament desmopathy in 26%, and hoof capsule and distal phalanx pathology in 10%. Only 25% of the navicular bone disease cases were considered clinically significant. The majority of deep digital flexor tendon lesions (77%) and distal interphalangeal joint osteoarthritis (51%) were considered significant. Approximately one third of navicular bursa (37%) and collateral ligament (33%) abnormalities were considered significant. Navicular bursa abnormalities were associated with navicular bone and deep digital flexor tendon lesions. The findings support the hypothesis and the use of this protocol for evaluation of foot lameness

    Relativistic Operator Description of Photon Polarization

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    We present an operator approach to the description of photon polarization, based on Wigner's concept of elementary relativistic systems. The theory of unitary representations of the Poincare group, and of parity, are exploited to construct spinlike operators acting on the polarization states of a photon at each fixed energy momentum. The nontrivial topological features of these representations relevant for massless particles, and the departures from the treatment of massive finite spin representations, are highlighted and addressed.Comment: Revtex 9 page
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