9,370 research outputs found

    The gluon polarization ΔG/G\Delta G/G at COMPASS

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    The COMPASS experiment will determine the gluon polarization in the nucleon ΔG/G\Delta G/G from the double helicity asymmetry measured in the scattering of a 160 GeV muon beam on a longitudinally polarized deuteron target, by selecting the photon-gluon fusion reaction. This reaction can be tagged either by the production of open charm, or by the production of high pTp_T hadron pairs. The first asymmetry obtained with the latter method is presented.Comment: 4 pages, 7 figure

    Winning in the long run: a quantified approach to the drivers of sustainable financial value on real estate: Working Paper 2

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    This working paper describes the first empirical study measuring the impact of sustainability characteristics on the financial performance of European office and retail properties. The authors present the project, the issue and the approach of their ongoing search for a �Green Alpha�. In a joint effort, university experts at Danube University Krems are in cooperation with Kingston University London tackling a robust analysis on hard data from real properties of institutional investment portfolios in the United Kingdom, France, the Netherlands, Germany, Switzerland and Austria. Their first results are expected by the end of 2010

    Increase of metallothionein-immunopositive chloride cells in the gills of brown trout and rainbow trout after exposure to sewage treatment plant effluents

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    Metallothionein, a biomarker of exposure and toxicity of heavy metals, has been detected in the gills of brown trout (Salmo trutta fario L.) and rainbow trout (Oncorhynchus mykiss Richardson) by means of immunohistochemistry. A very prominent labelling of chloride cells was found after exposure to diluted sewage plant effluents. No significant increase was observed in either the number of labelled cells or their labelling intensity after exposure to water of a polluted river compared to fish kept in tap water. These results do not correlate with findings of a histopathological study, suggesting that the metal levels at the sewage treatment plant were too low to produce gross histopathology. A comparison between the species indicated that the rainbow trout showed a generally higher metallothionein expression than the brown trout

    Atomic matter wave scanner

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    We report on the experimental realization of an atom optical device, that allows scanning of an atomic beam. We used a time-modulated evanescent wave field above a glass surface to diffract a continuous beam of metastable Neon atoms at grazing incidence. The diffraction angles and efficiencies were controlled by the frequency and form of modulation, respectively. With an optimized shape, obtained from a numerical simulation, we were able to transfer more than 50% of the atoms into the first order beam, which we were able to move over a range of 8 mrad.Comment: 4 pages, 4 figure

    Rapid pressure compensation by automated cuff pressure controllers worsens sealing in tracheal tubes

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    Background Cyclic redistribution of air within the cuff during respiratory pressure changes creates a self-sealing mechanism which allows tracheal sealing, despite tracheal airway pressure being above baseline cuff inflation pressure. The aim of the present study was to investigate the effect of continuous automated cuff pressure regulation on tracheal sealing during cyclic respiratory pressure changes. Methods In vitro tracheal sealing was studied in four different high volume-low pressure (HVLP) tracheal tube cuffs size internal diameter 8.0 and 5.0 mm in combination with a conventional pressure manometer and two different automated pressure controllers (VBM Cuff Controller; Cuff Pressure Control Tracoe™). Experiments were performed at 10, 15, 20, and 25 cm H2O cuff pressure during intermittent positive pressure ventilation with peak inspiratory pressures of 20 and 25 cm H2O. Air leakage was assessed spirometrically. Experiments were performed four times with each tube brand and size with two exemplars of each of the three cuff pressure controllers. Results Owing to immediate cuff pressure correction, tracheal sealing at cuff pressure below inspiratory pressure was reduced in most of the tracheal tube cuffs, except in those with reduced sealing characteristics when using the Pressure Control Tracoe™ compared with the conventional pressure manometer and the VBM Cuff Controller. Tracheal sealing with the Pressure Control Tracoe™ comparable with the other two devices was only achieved at cuff pressures of 20 and 25 cm H2O. Conclusions Automated cuff pressure controllers with rapid pressure correction interfere with the self-sealing mechanism of high sealing HVLP tube cuffs and reduce their improved sealing characteristic

    In-line filter included into the syringe infusion pump assembly reduces flow irregularities

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    Purpose: To evaluate whether an in-line filter inserted in the syringe pump infusion line assembly influences start-up times and flow irregularities during vertical pump displacement at low infusion rates. Methods: Fluid delivery after syringe pump start-up and after vertical displacement of the syringe pump by −50cm was determined gravimetrically at flow rates of 0.5, 1.0 and 2.0mlh−1. Measurements were repeated for each flow rate four times with two different syringe pumps with and without an in-line filter incorporated. Data are shown as median and range. Results: Start-up times were reduced by an in-line filter at 0.5mlh−1 flow rate from 355.5s (0-660) to 115s (0-320), whereas the effect was attenuated at higher flow rates. Pooling of fluid into the infusion system after lowering the infusion syringe pump was halved in all flow rates tested. Amount of infusion bolus after elevating the syringe pump by 50cm was not affected by an in-line filter. Conclusion: In the evaluated model in-line filters help to reduce flow irregularities and delay in drug delivery of syringe pumps at low flow rates and represent an option to optimize continuous administration of highly concentrated short-acting drugs at very small infusion rate

    Implementation of mean-timing and subsequent logic functions on an FPGA

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    This article describes the implementation of a mean-timer and coincidence logic on a Virtex-5 FPGA for trigger purposes in a particle physics experiment. The novel feature is that the mean-timing and the coincidence logic are not synchronized with a clock which allows for a higher resolution of approximately 400 ps, not limited by a clock frequency.Comment: 15 pages, 11 figure

    Sum Rules and Moments of the Nucleon Spin Structure Functions

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    The nucleon has been used as a laboratory to investigate its own spin structure and Quantum Chromodynamics. New experimental data on nucleon spin structure at low to intermediate momentum transfers combined with existing high momentum transfer data offer a comprehensive picture of the transition region from the {\it confinement} regime of the theory to its {\it asymptotic freedom} regime. Insight for some aspects of the theory is gained by exploring lower moments of spin structure functions and their corresponding sum rules (i.e. the Gerasimov-Drell-Hearn, Bjorken and Burkhardt-Cottingham). These moments are expressed in terms of an operator product expansion using quark and gluon degrees of freedom at moderately large momentum transfers. The sum rules are verified to a good accuracy assuming that no singular behavior of the structure functions is present at very high excitation energies. The higher twist contributions have been examined through the moments evolution as the moments evolution as the momentum transfer varies from higher to lower values. Furthermore, QCD-inspired low-energy effective theories, which explicitly include chiral symmetry breaking, are tested at low momentum transfers. The validity of these theories is further examined as the momentum transfer increases to moderate values. It is found that chiral perturbation calculations agree reasonably well with the first moment of the spin structure function g1g_1 at momentum transfer of 0.1 GeV2^2 but fail to reproduce the neutron data in the case of the generalized polarizability δLT\delta_{LT}.Comment: 21 pages, 4 figures, review for Modern Physics Letters A. Minor modifications in text and improved quality for one figure. Corrected mistakes in section

    Exact theory of kinkable elastic polymers

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    The importance of nonlinearities in material constitutive relations has long been appreciated in the continuum mechanics of macroscopic rods. Although the moment (torque) response to bending is almost universally linear for small deflection angles, many rod systems exhibit a high-curvature softening. The signature behavior of these rod systems is a kinking transition in which the bending is localized. Recent DNA cyclization experiments by Cloutier and Widom have offered evidence that the linear-elastic bending theory fails to describe the high-curvature mechanics of DNA. Motivated by this recent experimental work, we develop a simple and exact theory of the statistical mechanics of linear-elastic polymer chains that can undergo a kinking transition. We characterize the kinking behavior with a single parameter and show that the resulting theory reproduces both the low-curvature linear-elastic behavior which is already well described by the Wormlike Chain model, as well as the high-curvature softening observed in recent cyclization experiments.Comment: Revised for PRE. 40 pages, 12 figure
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