1,342 research outputs found

    Quantifying physiological influences on otolith microchemistry

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    Trace element concentrations in fish earstones (‘otoliths’) are widely used to discriminate spatially discrete populations or individuals of marine fish, based on a commonly held assumption that physiological influences on otolith composition are minor, and thus variations in otolith elemental chemistry primarily reflect changes in ambient water chemistry. We carried out a long-term (1-year) experiment, serially sampling seawater, blood plasma and otoliths of mature and immature European plaice (Pleuronectes platessa L.) to test relationships between otolith chemistry and environmental and physiological variables. Seasonal variations in otolith elemental composition did not track seawater concentrations, but instead reflected physiological controls on metal transport and biokinetics, which are likely moderated by ambient temperature. The influence of physiological factors on otolith composition was particularly evident in Sr/Ca ratios, the most widely used elemental marker in applied otolith microchemistry studies. Reproduction also triggered specific variations in otolith and blood plasma metal chemistry, especially Zn/Ca ratios in female fish, which could potentially serve as retrospective spawning indicators. The influence of physiology on the trace metal composition of otoliths may explain the success of microchemical stock discrimination in relatively homogenous marine environments, but could complicate alternative uses for trace element compositions in biominerals of higher organism

    Electroweak Theory Without Higgs Bosons

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    A perturbative SU(2)_L X U(1)_Y electroweak theory containing W, Z, photon, ghost, lepton and quark fields, but no Higgs or other fields, gives masses to W, Z and the non-neutrino fermions by means of an unconventional choice for the unperturbed Lagrangian and a novel method of renormalisation. The renormalisation extends to all orders. The masses emerge on renormalisation to one loop. To one loop the neutrinos are massless, the A -> Z transition drops out of the theory, the d quark is unstable and S-matrix elements are independent of the gauge parameter xi.Comment: 27 pages, LaTex, no figures; revised for publication; accepted by Int. J. Mod. Phys. A; includes biographical note on A. F. Nicholso

    Avoiding hospital admission in COPD: impact of a specialist nursing team

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    Chronic obstructive pulmonary disease (COPD) is a common, preventable and incurable disease. The costs of caring for patients with COPD is estimated to be more than £800 million a year for acute hospital admissions alone (Department of Health, 2012). The hospital-at-home model is increasingly being adopted for COPD patients following British Thoracic Society (BTS) guidelines for the delivery of hospital admission-avoidance schemes (BTS, 2007). The aim of this case-note review was to evaluate the safety and effectiveness of a specialist nurse-led acute respiratory assessment service working with COPD patients in the community. The review recorded patient flow through the service and documented assessments and treatments. It was able to document potential benefits and cost savings

    Prospects for Spin Physics at RHIC

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    Colliding beams of 70% polarized protons at up to s\sqrt{s}=500 GeV, with high luminosity, L=2×1032\times10^{{\rm 32}} cm2^{-2}sec1^{-1}, will represent a new and unique laboratory for studying the proton. RHIC-Spin will be the first polarized-proton collider and will be capable of copious production of jets, directly produced photons, and WW and ZZ bosons. Features will include direct and precise measurements of the polarization of the gluons and of uˉ\bar{u}, dˉ\bar{d}, uu, and dd quarks in a polarized proton. Parity violation searches for physics beyond the standard model will be competitive with unpolarized searches at the Fermilab Tevatron. Transverse spin will explore transversity for the first time, as well as quark-gluon correlations in the proton. Spin dependence of the total cross section and in the Coulomb nuclear interference region will be measured at collider energies for the first time. These qualitatively new measurements can be expected to deepen our understanding of the structure of matter and of the strong interaction.Comment: 51 pages, 22 figures. Scheduled to appear in the Annual Review of Nuclear and Particle Science Vol. 50, to be published in December 2000 by Annual Reviews, http://AnnualReviews.or

    An absolute polarimeter for high energy protons

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    A study of the spin asymmetries for polarized elastic proton proton collisions in the electromagnetic hadronic interference (CNI) region of momentum transfer provides a method of self calibration of proton polarization. The method can be extended to non-identical spin half scattering so that, in principle, the polarization of a proton may be obtained through an analysis of its elastic collision with a different polarized particle, helium 3 for instance. Sufficiently large CNI spin asymmetries provide enough information to facilitate the evaluation of nearly all the helicity amplitudes at small t as well as the polarization of both initial spin half fermions. Thus it can serve equally well as a polarimeter for helium 3

    Behavioral outcome measures to improve experimental stroke research

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    Functional recovery after an experimental stroke can be assessed by multiple behavioural tests, however, there is no consensus about which test to use in long-term stroke recovery studies or whether the tests are affected by stroke surgery, post-operative care or behavioural compensation due to repeated testing. This review describes the tests most commonly used to assess motor and sensorimotor function, cognition and mood in stroke animals. Although it is difficult to predict the direction of future research, it may be possible to prevent false-positive results by selecting an appropriate task or a battery of tasks. It is also expected that the upcoming stroke recovery recommendations and the improved dialogue between academy, industry and healthcare professionals will further promote translational success

    Lickometry: A novel and sensitive method for assessing functional deficits in rats after stroke

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    The need for sensitive, easy to administer assessments of long-term functional deficits is crucial in pre-clinical stroke research. In the present study, we introduce lickometry (lick microstructure analysis) as a precise method to assess sensorimotor deficits up to 40 days after middle cerebral artery occlusion in rats. Impairments in drinking efficiency compared to controls, and a compensatory increase in the number of drinking clusters were observed. This highlights the utility of this easy to administer task in assessing subtle, long-term deficits, which could be likened to oral deficits in patients

    The cost-effectiveness of exercise referral schemes

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    This is a freely-available open access publication. Please cite the published version which is available via the DOI link in this record.Exercise referral schemes (ERS) aim to identify inactive adults in the primary care setting. The primary care professional refers the patient to a third party service, with this service taking responsibility for prescribing and monitoring an exercise programme tailored to the needs of the patient. This paper examines the cost-effectiveness of ERS in promoting physical activity compared with usual care in primary care setting.NIHR Health Technology Assessment programm

    A calculation of the Lepage-Mackenzie scale for the lattice axial and vector currents

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    We calculate the perturbative scales (q*) for the axial and vector currents for the Wilson action, with and without tadpole improvement, using Lepage and Mackenzie's formalism. The scale for the pseudoscalar density (times the mass) is computed as well. Contrary to naive expectation, tadpole improvement reduces q* by only a small amount for the operators we consider. We also discuss the use of a nonperturbative coupling to calculate the perturbative scale.Comment: 13 pages. One postscript figur
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