49,207 research outputs found

    Thermal performance of a photographic laboratory process: Solar Hot Water System

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    The thermal performance of a solar process hot water system is described. The system was designed to supply 22,000 liters (5,500 gallons) per day of 66 C (150 F) process water for photographic processing. The 328 sq m (3,528 sq. ft.) solar field has supplied 58% of the thermal energy for the system. Techniques used for analyzing various thermal values are given. Load and performance factors and the resulting solar contribution are discussed

    The Electromagnetic Self-Energy Contribution to M_p - M_n and the Isovector Nucleon Magnetic Polarizability

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    We update the determination of the isovector nucleon electromagnetic self-energy, valid to leading order in QED. A technical oversight in the literature concerning the elastic contribution to Cottingham's formula is corrected and modern knowledge of the structure functions is used to precisely determine the inelastic contribution. We find \delta M_{p-n}^\gamma = 1.30(03)(47) MeV. The largest uncertainty arises from a subtraction term required in the dispersive analysis, which can be related to the isovector magnetic polarizability. With plausible model assumptions, we can combine our calculation with additional input from lattice QCD to constrain this polarizability as: \beta_{p-n} = -0.87(85) x 10^{-4} fm^3.Comment: 5 pages, version accepted for publication in PR

    Oxidative Heck desymmetrisation of 2,2-disubstituted cyclopentene-1,3-diones

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    Oxidative Heck couplings have been successfully developed for 2,2-disubstituted cyclopentene-1,3-diones. The direct coupling onto the 2,2-disubstituted cyclopentene-1,3-dione core provides a novel expedient way of enantioselectively desymmetrising all-carbon quaternary centres

    The X-ray coronae of the two brightest galaxies in the Coma cluster

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    We use deep Chandra X-ray Observatory observations to examine the coronae of the two brightest cluster galaxies in the Coma cluster of galaxies, NGC 4874 and NGC 4889. We find that NGC 4889 hosts a central depression in X-ray surface brightness consistent with a cavity or pair of cavities of radius 0.6 kpc. If the central cavity is associated with an AGN outburst and contains relativistic material, its enthalpy should be around 5x10^55 erg. The implied heating power of this cavity would be around an order of magnitude larger than the energy lost by X-ray emission. It would be the smallest and youngest known cavity in a brightest cluster galaxy and the lack of over pressuring implies heating is still gentle. In contrast, NGC 4874 does not show any evidence for cavities, although it hosts a well-known wide-angle-tail radio source which is visible outside the region occupied by the X-ray corona. These two galaxies show that AGN feedback can behave in varied ways in the same cluster environment.Comment: 11 pages, 11 figures, accepted by MNRA

    Quantitative Analysis of Candida Cell Wall Components by Flow Cytometrywith Triple-Fluorescence Staining

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    This work was supported by the European Commission within the FP7 Framework Programme [Fungitect-Grant No 602125]. We also thank Thomas Sauer, Vienna Biocenter Campus (VBC), Austria, for technical support at the FACS facility of the MFPL, Karl Kuchler, MFPL-Department of Medical Biochemistry, Medical University of Vienna, Max F. Perutz Laboratories, Campus Vienna Biocenter, Vienna, Austria and Ernst Thuer, Centre for Genomic Regulation, Barcelona, Spain, for advice on statistical approaches. Neil Gow acknowledges the support of the Wellcome Trust and the MRC Centre for Medical MycologyPeer reviewedPublisher PD

    Magnetic excitations in vanadium spinels

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    We study magnetic excitations in vanadium spinel oxides AV2_2O4_4 (A=Zn, Mg, Cd) using two models: first one is a superexchange model for vanadium S=1 spins, second one includes in addition spin-orbit coupling, and crystal anisotropy. We show that the experimentally observed magnetic ordering can be obtained in both models, however the orbital ordering is different with and without spin-orbit coupling and crystal anisotropy. We demonstrate that this difference strongly affects the spin-wave excitation spectrum above the magnetically ordered state, and argue that the neutron measurement of such dispersion is a way to distinguish between the two possible orbital orderings in AV2_2O4_4.Comment: accepted in Phys. Rev.

    An Evaluation of Physical Activity Levels amongst University Employees

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    Approximately 60% of the world’s population do not meet the physical activity (PA) guidelines. Physical inactivity is increasing in occupations, with work-related health issues becoming more prevalent. University employees’ work in a range of job roles and PA levels in this population is unclear. Thus, this study aimed to evaluate PA levels amongst university employees in a UK Higher Education institution. Four hundred employees (male = 131, female = 269) partook in this quantitative study and completed an online International Physical Activity Questionnaire Long Form (IPAQ-LF) to assess total moderate to vigorous PA (MVPA) and work-related MVPA. A Mann-Whitney U test examined differences in total MVPA and work-related MVPA between genders and a Kruskal-Wallis H test examined differences in total MVPA and work related MVPA between job roles. The findings showed that university employees engaged in a median of 330 minutes and 1770 METs of MVPA across all domains of IPAQ-LF. Further, the median time spent in total work PA was 30 minutes and 123 METs. There was a significant difference between genders, as males engaged in 150 minutes more total MVPA compared to females (p 0.05). Findings suggest that job role does not affect PA levels within university workplace, although they do propose that males engage in more MVPA compared to females. As a result of the subjective nature of this research, objective research is required to confirm current findings
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