1,115 research outputs found

    The Effect of Sward Height and Bulk Density on Herbage Intake and Grazing Behaviour of Dairy Cows

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    The effects of sward height and bulk density on herbage intake and grazing behaviour of dairy cows during 1 hour grazing periods was investigated. Sward factors had a marked effect on dry matter (DM) intake/bite, which ranged from 0.4 to 1.1 g, and this was reflected in hourly intake rates. Intake/bite was largely influenced by sward height, reflecting increased bite depth in taller swards, with inherent differences between swards at low sward heights largely attributable to differences in bulk density (BD). The results indicate that DM intake rates up to 4.0 kg DM/hour can be achieved in short term grazing studies with dairy cows grazing tall (180 mm+), dense (3.0 kg DM/m3), leafy perennial ryegrass swards

    Towards transforming community eye care: an observational study and time-series analysis of optometrists' prescribing for eye disorders

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    Objectives: This study aimed to provide evidence on the therapeutic prescribing activity by community optometrists in Scotland and to determine its impact on workload in general practice and ophthalmology clinics. Study design: Scottish administrative healthcare data for a 53-month period (November 2013–April 2018) were used to analyse non-medical prescribing practice by optometrists. Methods: Using interrupted time-series regression (Autoregressive Integrated Moving Average), we assessed the impact of optometrist prescribing on ophthalmology outpatient attendances and general practice prescribing for eye disorders. Results: A total of 54,246 items were prescribed by 205 optometrists over the study period. Since the commencement of data recording, optometrist prescribing activity increased steadily from a baseline of zero to 1.2% of all ophthalmic items prescribed. Neither the monthly number of items prescribed nor the size of optometric workforce were associated with a reduction in ophthalmology outpatient appointments over time. Conclusions: Optometrists increasingly contribute to community ophthalmic prescribing in Scotland, releasing capacity and lessening general practice, but not secondary care workload. There appears to be an underutilisation of optometrists related to the management of dry eye, which represents an opportunity to release further capacity

    An Analysis of the Representations of the Mapping Class Group of a Multi-Geon Three-Manifold

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    It is well known that the inequivalent unitary irreducible representations (UIR's) of the mapping class group GG of a 3-manifold give rise to ``theta sectors'' in theories of quantum gravity with fixed spatial topology. In this paper, we study several families of UIR's of GG and attempt to understand the physical implications of the resulting quantum sectors. The mapping class group of a three-manifold which is the connected sum of R3\R^3 with a finite number of identical irreducible primes is a semi-direct product group. Following Mackey's theory of induced representations, we provide an analysis of the structure of the general finite dimensional UIR of such a group. In the picture of quantized primes as particles (topological geons), this general group-theoretic analysis enables one to draw several interesting qualitative conclusions about the geons' behavior in different quantum sectors, without requiring an explicit knowledge of the UIR's corresponding to the individual primes.Comment: 52 pages, harvmac, 2 postscript figures, epsf required. Added an appendix proving the semi-direct product structure of the MCG, corrected an error in the characterization of the slide subgroup, reworded extensively. All our analysis and conclusions remain as befor

    Normal human breast xenografts activate N-nitrosodimethylamine: identification of potential target cells for an environmental nitrosamine.

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    Normal human breast tissue maintained as xenografts in female Balb/c (nu/nu) athymic mice is capable of metabolising N-nitrosodimethylamine (NDMA) to active intermediates that will react with DNA. Administration of NDMA to mice with slow-release implants of 17 beta-oestradiol which provide human physiological (luteal phase) circulating oestrogen levels and increase cell proliferation in the xenograft (Laidlaw et al., 1992), leads to an apparent increase in the extent of reaction with DNA compared to controls without oestrogen implants. In mice with oestrogen implants, measurements of the amounts of the promutagenic lesion, O6-methyl-2'-deoxyguanosine formed in DNA clearly indicated a dose related increase in the extent of reaction. Detection of O6-methyl-2'-deoxyguanosine using immunohistochemical procedures revealed that the nuclei of cells of the glandular epithelium, supportive tissue and adipose tissue, in decreasing order of prevalence, were positively stained for the presence of this DNA lesion. Epithelial cells, which are the putative target cells for carcinogenesis in the breast, are therefore prone to promutagenic damage as a result of exposure to an environmental nitrosamine

    Unitary Equivalence of the Metric and Holonomy Formulations of 2+1 Dimensional Quantum Gravity on the Torus

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    Recent work on canonical transformations in quantum mechanics is applied to transform between the Moncrief metric formulation and the Witten-Carlip holonomy formulation of 2+1-dimensional quantum gravity on the torus. A non-polynomial factor ordering of the classical canonical transformation between the metric and holonomy variables is constructed which preserves their classical modular transformation properties. An extension of the definition of a unitary transformation is briefly discussed and is used to find the inner product in the holonomy variables which makes the canonical transformation unitary. This defines the Hilbert space in the Witten-Carlip formulation which is unitarily equivalent to the natural Hilbert space in the Moncrief formulation. In addition, gravitational theta-states arising from ``large'' diffeomorphisms are found in the theory.Comment: 31 pages LaTeX [Important Revision: a section is added constructing the inner product/Hilbert space for the Witten-Carlip holonomy formulation; the proof of unitary equivalence of the metric and holonomy formulations is then completed. Other additions include discussion of relation of canonical and unitary transformations. Title/abstract change.

    Regulation and Rose of Heme Oxygenase-1 (HO-1) During Inflammation in Human Gingival Fibroblasts (HGF)

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    Periodontitis is the most common cause of adult tooth loss in the U.S., with an estimated 1 in 3 adults suffering from some form and 10-15% of adults developing severe forms. In addition to its direct impact, periodontitis also contributes to the development of several other diseases, including cardiovascular disease, pre-term low birth weight, and diabetes. Although the primary function of HO-1 is the breakdown of heme to carbon monoxide, iron and bilirubin, it has also been shown to play an important role in wound repair and the resolution of inflammation by mechanisms involving homeostatic regulation of the redox state of cells. A series of experiments has been designed to determine whether and to what extent the levels of HO-1 mRNA and protein are regulated by inflammatory cytokines in HGF isolated from individuals with or without periodontitis. Preliminary results show that HO-1 mRNA is expressed in HGF cultures derived from patients with periodontitis and that mRNA levels are inhibited over 60% by Interleukin-1 at 6 hours (10 ng/ml, p \u3c 0.001). Interestingly however, HO-1 protein levels as measured by ELISA are not decreased by IL-1. Experiments are currently underway to address this apparent paradox, as well as the potential role of HO-1 in the regulation of inflammatory mediators in HGF

    Fractional Exclusion Statistics and Anyons

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    Do anyons, dynamically realized by the field theoretic Chern-Simons construction, obey fractional exclusion statistics? We find that they do if the statistical interaction between anyons and anti-anyons is taken into account. For this anyon model, we show perturbatively that the exchange statistical parameter of anyons is equal to the exclusion statistical parameter. We obtain the same result by applying the relation between the exclusion statistical parameter and the second virial coefficient in the non-relativistic limit.Comment: 9 pages, latex, IFT-498-UN

    How do United Kingdom (UK) medical schools identify and support undergraduate medical students who 'fail' communication assessments? : A national survey.

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    Acknowledgements Thanks go to Kirsty Boyd for discussion of early versions of the results of this survey. Grateful thanks to the UK Council for Clinical Communication in Undergraduate Medical Eduction for support of and contribution to this work.Peer reviewedPublisher PD

    Remarks on the Configuration Space Approach to Spin-Statistics

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    The angular momentum operators for a system of two spin-zero indistinguishable particles are constructed, using Isham's Canonical Group Quantization method. This mathematically rigorous method provides a hint at the correct definition of (total) angular momentum operators, for arbitrary spin, in a system of indistinguishable particles. The connection with other configuration space approaches to spin-statistics is discussed, as well as the relevance of the obtained results in view of a possible alternative proof of the spin-statistics theorem.Comment: 18 page
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