7,260 research outputs found

    K-Matrix Analysis of the (IJPC=00++{IJ}^{PC}=00^{++}) Amplitude in the Mass Region up to 1550 MeV

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    K-matrix analysis of the 00++00^{++} wave is performed in the channels ππ, KKˉ, ηη\pi\pi,~K\bar K,~\eta\eta and 4π4\pi in the mass region up to 1550 MeV. The fit is based on the following data: ppˉ (at rest)π0π0π0p\bar p ~(at~rest)\to \pi^0\pi^0\pi^0, π0π0η, π0ηη\pi^0\pi^0\eta,~\pi^0\eta\eta [1,2], πNππN\pi N\to \pi\pi N [3,4], πNKKˉN\pi N\to K\bar K N [5] and the inelastic cross section of the ππ\pi\pi interaction [6]. Simultaneous analysis of these data confirms the existence of the scalar resonances: f0(980), f0(1300)f_0(980),~f_0(1300) and f0(1500)f_0(1500), the poles of the amplitude being at the following complex masses (in MeV): (1008±10)i(43±5)(1008\pm 10)- i(43\pm 5), (1290±25)i(120±15)(1290\pm 25)-i(120\pm 15), and (1497±6)i(61±5)(1497\pm 6)-i(61\pm 5). The fourth pole has sunk deeply into the complex plane: (1430±150)i(600±100)(1430 \pm 150) - i(600\pm 100). Positions of the K-matrix poles (which are referred to the masses of bare states) are at 750±120750\pm 120 MeV, 1240±301240\pm 30 MeV, 1280±301280\pm 30 MeV and 1615±401615\pm 40 MeV. Coupling constants of the K-matrix poles to the ππ\pi\pi, ηη\eta\eta and KKˉK\bar K channels are found that allow us to analyze the quark and gluonic content of bare states. It is shown that f0bare(1240)f_0^{bare}(1240) and f0bare(1615)f_0^{bare}(1615) (which are strongly related to f0(1500)f_0(1500)) can be considered as good candidates for scalar glueball.Comment: 19 pages, LATEX, 6 figures in one uu-fil

    open-UST: An Open-Source Ultrasound Tomography Transducer Array System

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    Fast imaging methods are needed to promote widespread clinical adoption of Ultrasound Tomography (UST), and more widely available UST hardware could support the experimental validation of new measurement configurations. In this work, an open-source 256-element transducer ring array was developed (morganjroberts.github.io/open-UST) and manufactured using rapid prototyping, for only £2k. Novel manufacturing techniques were used, resulting in a 1.17° mean beam axis skew angle, a 104 μm mean element position error, and a ±13.6 μm deviation in matching layer thickness. The nominal acoustic performance was measured using hydrophone scans and watershot data, and the 61.2 dB SNR, 55.4° opening angle, 10.2 mm beamwidth and 54% transmit-receive bandwidth (-12 dB), were found to be similar to existing systems, and compatible with state of the art full-waveform-inversion image reconstruction methods. The inter-element variation in acoustic performance was typically <10% without using normalisation, meaning that the elements can be modelled identically during image reconstruction, removing the need for individual source definitions based on hydrophone measurements. Finally, data from a phantom experiment was successfully reconstructed. These results demonstrate that the open-UST system is accessible for users, and suitable for UST imaging research

    A new microbothriid monogenean Dermopristis pterophilus n. sp. from the skin of the Critically Endangered green sawfish Pristis zijsron Bleeker, 1851 (Batoidea: Pristidae) in Western Australia

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    A new microbothriid monogenean Dermopristis pterophilus n. sp. is described from the skin of the Critically Endangered green sawfish Pristis zijsron Bleeker, 1851 in the Ashburton River delta, northern Western Australia. Analyses of the 28S ribosomal DNA marker and the molecular barcoding markers Histone 3 and Elongation Factor 1 α confirmed position among the Microbothriidae, with close affinity to the only other sequenced representative of Dermopristis Kearn, Whittington and Evans-Groing, 2010. The new species is morphologically consistent with the concept of Dermopristis; it has two testes, lacks a male copulatory organ and has a simple haptor. It is smaller than its two congeners D. paradoxus Kearn, Whittington and Evans-Gowing, 2010 and D. cairae Whittington and Kearn, 2011 and is most similar to the former, distinguished only in that it lacks the strong, transverse, parallel ridges on the ventral body surface that characterise that species. It is more easily distinguished from D. cairae, differing in body shape, possession of a seminal receptacle, and relative position and size of the haptor. It may further differ from both species by fine details of the gut diverticula, although these details are difficult to ascertain. Spermatophores were observed in the new species, similar to those previously reported for D. cairae. The new species exhibits site attachment preference: infections were greatest on and immediately adjacent to the host pelvic fins (including male reproductive organs, i.e. claspers), moderate in proximity to the dorsal and pectoral fins, few on the caudal fin and peduncle, and infrequently, isolated worms occurred elsewhere on the dorsal and ventral surfaces of the body. There was no incidence of infection on the head (including rostrum). We presume D. pterophilus is restricted to P. zijsron and thus likely faces the same threat of extinction

    A survey of Edwardsiella ictaluri in wild catfish populations in Australia

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    This report contains the findings of the first survey of the exotic bacterium Edwardsiella ictaluri in wild freshwater fish populations in Australia. Edwardsiella ictaluri causes enteric septicaemia of catfish (ESC), which is a serious disease of farmed channel catfish in the USA. The bacterium has previously been detected in imported ornamental fish and in native catfish held in Australian aquarium facilities, but wild fish populations in Australia are considered free of the disease. The Australian Government Department of Agriculture, through the Fisheries Research and Development Corporation, funded an active surveillance program to provide further evidence for this claim of disease freedom

    Health assets in a global context: a systematic review of the literature.

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    OBJECTIVE: To provide an up-to-date overview of health assets in a global context both from a theoretical perspective and its practical applications to address health inequalities and achieve sustainable health. DESIGN: A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. DATA SOURCES: A comprehensive search, including 10 electronic bibliographic databases and hand searches, was undertaken to capture the wide range of terms associated with 'health assets' and 'asset-based approaches to health'. ELIGIBILITY CRITERIA: Any peer-reviewed published and grey literature in English related to 'health assets' or 'assets' in a 'health' context was included without any date, country or study design restrictions and the quality of evidence was appraised according to the Oxford Level of Evidence. OUTCOMES: A broad consideration of all outcome measures including clinical outcomes, patient-level, community-level and population-level impacts and costs, was adopted. RESULTS: 478 publications were included. Health assets were researched in 40 countries, predominantly in the West such as the USA and the UK. A number of broad health assets were identified including community and individual assets. Even though research was conducted in a number of different settings, most occurred in the community, clinical, care or educational settings. A wide variety of interventions and approaches were implemented, most commonly related to education and/or training, asset mapping or asset approaches. CONCLUSIONS: Globally, authors most often referred to general 'health assets', 'assets' or some form of 'community asset' in relation to health. Overall, the idea of health assets is framed within a positive paradigm focusing on health creation rather than curative approaches. The sustained credibility of the global 'health assets' literature depends on future research on definitional, theoretical and evaluative issues in order to convince policy-makers and service commissioners of its necessity and added value to the traditional deficit approach

    Structure and Magnetization of Two-Dimensional Vortex Arrays in the Presence of Periodic Pinning

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    Ground-state properties of a two-dimensional system of superconducting vortices in the presence of a periodic array of strong pinning centers are studied analytically and numerically. The ground states of the vortex system at different filling ratios are found using a simple geometric argument under the assumption that the penetration depth is much smaller than the spacing of the pin lattice. The results of this calculation are confirmed by numerical studies in which simulated annealing is used to locate the ground states of the vortex system. The zero-temperature equilibrium magnetization as a function of the applied field is obtained by numerically calculating the energy of the ground state for a large number of closely spaced filling ratios. The results show interesting commensurability effects such as plateaus in the B-H diagram at simple fractional filling ratios.Comment: 12 pages, 19 figures, submitted for publicatio

    Economies of space and the school geography curriculum

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    This paper is about the images of economic space that are found in school curricula. It suggests the importance for educators of evaluating these representations in terms of the messages they contain about how social processes operate. The paper uses school geography texts in Britain since the 1970s to illustrate the different ways in which economic space has been represented to students, before exploring some alternative resources that could be used to provide a wider range of representations of economic space. The paper highlights the continued importance of understanding the politics of school knowledge
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