52 research outputs found

    The Geometry and Kinematics of the Broad-Line Region in NGC 5548 from HST and IUE Observations

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    The spatial and radial velocity distribution of broad-line-emitting gas in the Seyfert 1 galaxy NGC 5548 is examined through the process of reverberation mapping, which is done by detailed comparison of continuum and emission-line variations. Recent spectroscopic monitoring of NGC 5548 with HST and IUE allows us to resolve the transfer function (TF) that relates the continuum and emission-line variability. We also examine the radial velocity-resolved TFs, and confirm that predominantly radial motions of the line-emitting clouds can be excluded. We find that a broad-line region comprised of clouds that are orbiting a central source of mass ~108 M☉ along randomly inclined Keplerian orbits and irradiated by a beamed continuum source yields a TF and line profile that are qualitatively consistent with the observations. In this model, the clouds that produce the variable C IV emission lie within 12 lt-days of the central source, and the continuum radiation is confined to a wide biconical beam (semi-opening angle 35°-60°) with the observer viewing into the cone

    Playing on common ground: Spaces of sport, education and corporate connectivity, contestation and creativity

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    In this article we examine connectivities within the ‘messy’ organizational commons of sport, education and corporate partnerships. As scholars forewarn, there are currently key stakeholders within the commons that that have set agendas, occupied ideological and physical terrain, and legitimized a presence and authority. The intertwining of organizations here is an evident function of an increased symbiosis between sport, education and governmental and non-governmental stakeholders to carve out significant sector spaces, and exert authority and power over the creation, implementation and ownership ‘collaborative’ and intersectional work. Drawing on spatial theorists, Henri Lefebvre and Yi Fu Tuan, and examples from FIFA and the IOC, we present a conceptual framework of global stakeholder relations. Focusing of processes of thought, production and action, we offer an intersectional critique of the nuances of Sport–Corporate–Education nexus and consider possibilities and potential for sport education spaces to be reconfigured ane

    The Geometry and Kinematics of the Broad-Line Region in NGC 5548 from HST and IUE Observations

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    The spatial and radial velocity distribution of broad-line-emitting gas in the Seyfert 1 galaxy NGC 5548 is examined through the process of reverberation mapping, which is done by detailed comparison of continuum and emission-line variations. Recent spectroscopic monitoring of NGC 5548 with HST and IUE allows us to resolve the transfer function (TF) that relates the continuum and emission-line variability. We also examine the radial velocity-resolved TFs, and confirm that predominantly radial motions of the line-emitting clouds can be excluded. We find that a broad-line region comprised of clouds that are orbiting a central source of mass ~108 M☉ along randomly inclined Keplerian orbits and irradiated by a beamed continuum source yields a TF and line profile that are qualitatively consistent with the observations. In this model, the clouds that produce the variable C IV emission lie within 12 lt-days of the central source, and the continuum radiation is confined to a wide biconical beam (semi-opening angle 35°-60°) with the observer viewing into the cone

    Intravitreal bevacizumab in the treatment of vasoproliferative retinal tumours

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    AIM: To evaluate the efficacy of intravitreal bevacizumab in the treatment of retinal vasoproliferative tumours (VPT). MATERIALS AND METHODS: Six eyes of 6 patients with VPT who received intravitreal bevacizumab were retrospectively reviewed. All patients received between one and three injections of intravitreal bevacizumab depending upon response to treatment. Best-corrected visual acuity (BCVA), tumour size, and presence of co-pathology or sequelae were noted pre- and postoperatively and then analysed. Subsequent retreatments were performed in patients with recurrent or persistent VPT according to the ophthalmologist's discretion. Retreatments included photodynamic therapy with verteporfin, ruthenium-106 plaque brachytherapy, or endoresection of tumour. RESULTS: The mean follow-up duration was 33.3 months (range 10–66 months). At baseline, the mean logMAR BCVA was 1.45 (Snellen equivalent of 6/165); range 0.10–1.90 (6/8—CF). Following bevacizumab treatment the mean logMAR BCVA was 0.98 (Snellen equivalent of 6/57); range 0.5–1.9 (Snellen equivalent of 6/19 to CF). Therefore, there was no statistically significant change in visual acuity. The mean tumour thickness reduced from 2.4 to 2.1 mm following treatment with bevacizumab. However, this did not reach the statistical significance of P<0.05. Despite the visual improvement following bevacizumab therapy, five out of six patients had recurrence of tumour activity during the follow-up period and required further intervention in order to achieve sustained regression. CONCLUSIONS: Intravitreal bevacizumab appeared to result in temporary reduction of tumour thickness in 3 out of 6 VPT patients. However, neither the reduction in tumour thickness nor the change in visual acuity were statistically significant and intravitreal bevacizumab monotherapy had limited effectiveness in causing long-term regression of the lesions. Additional therapy was indicated in five out of six patients to establish long-term regression. The efficacy of bevacizumab as an adjunct is as yet undetermined and further studies are needed. Presently, we recommend other treatment modalities in the long-term management of VPTs
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