122,180 research outputs found

    Scalar and vector meson exchange in V->P0P0gamma decays

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    The scalar contributions to the radiative decays of light vector mesons into a pair of neutral pseudoscalars, VP0P0γV\to P^0P^0\gamma, are studied within the framework of the Linear Sigma Model. This model has the advantage of incorporating not only the scalar resonances in an explicit way but also the constraints required by chiral symmetry. The experimental data on ϕπ0π0γ\phi\to\pi^0\pi^0\gamma, ϕπ0ηγ\phi\to\pi^0\eta\gamma, ρπ0π0γ\rho\to\pi^0\pi^0\gamma and ωπ0π0γ\omega\to\pi^0\pi^0\gamma are satisfactorily accommodated in our framework. Theoretical predictions for ϕK0Kˉ0γ\phi\to K^0\bar K^0\gamma, ρπ0ηγ\rho\to\pi^0\eta\gamma, ωπ0ηγ\omega\to\pi^0\eta\gamma and the ratio ϕf0γ/a0γ\phi\to f_0\gamma/a_0\gamma are also given.Comment: 42 pages, 11 figures. A new paragraph explaining the seminal contribution of Ref. [19] is adde

    Responsible research and innovation: A manifesto for empirical ethics?

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    In 2013 the Nuffield Council on Bioethics launched their report Novel Neurotechnologies: Intervening in the Brain. The report, which adopts the European Commission's notion of Responsible Research and Innovation, puts forward a set of priorities to guide ethical research into, and the development of, new therapeutic neurotechnologies. In this paper, we critically engage with these priorities. We argue that the Nuffield Council's priorities, and the Responsible Research and Innovation initiative as a whole, are laudable and should guide research and innovation in all areas of healthcare. However, we argue that operationalising Responsible Research and Innovation requires an in-depth understanding of the research and clinical contexts. Providing such an understanding is an important task for empirical ethics. Drawing on examples from sociology, science and technology studies, and related disciplines, we propose four avenues of social science research which can provide such an understanding. We suggest that these avenues can provide a manifesto for empirical ethics.The paper derives from a project that was funded by Wellcome Trust (Wellcome Trust Biomedical Strategic Award 086034)

    TEXES Observations of M Supergiants: Dynamics and Thermodynamics of Wind Acceleration

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    We have detected [Fe II] 17.94 um and 24.52 um emission from a sample of M supergiants using TEXES on the IRTF. These low opacity emission lines are resolved at R = 50, 000 and provide new diagnostics of the dynamics and thermodynamics of the stellar wind acceleration zone. The [Fe II] lines, from the first excited term, are sensitive to the warm plasma where energy is deposited into the extended atmosphere to form the chromosphere and wind outflow. These diagnostics complement previous KAO and ISO observations which were sensitive to the cooler and more extended circumstellar envelopes. The turbulent velocities, Vturb is about 12 to 13 km/s, observed in the [Fe II] forbidden lines are found to be a common property of our sample, and are less than that derived from the hotter chromospheric C II] 2325 Angstrom lines observed in alpha Ori, where Vturb is about 17 to 19 km/s. For the first time, we have dynamically resolved the motions of the dominant cool atmospheric component discovered in alpha Ori from multi-wavelength radio interferometry by Lim et al. (1998). Surprisingly, the emission centroids are quite Gaussian and at rest with respect to the M supergiants. These constraints combined with model calculations of the infrared emission line fluxes for alpha Ori imply that the warm material has a low outflow velocity and is located close to the star. We have also detected narrow [Fe I] 24.04 um emission that confirms that Fe II is the dominant ionization state in alpha Ori's extended atmosphere.Comment: 79 pages including 10 figures and 2 appendices. Accepted by Ap

    Designs on the Web: A case study of online learning for design students

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    The De Montfort University Electronic Campus initiative started in September 1999. Web‐based learning resources and support have been provided for over 3,000 students via a portfolio of thirty projects ranging across all levels of the university and within every faculty. This paper focuses on one aspect of this initiative: the development of online teaching and learning materials to support first‐year IT modules for students of art and design. An undergraduate module has been converted from traditional, face‐to‐face, delivery to a hybrid combination of Web‐based and studio‐based work in accordance with Laurillard's conversational framework. In the first year of use all the new material has been made available on a pilot basis to a group of 440 students in parallel with conventional lectures and seminars. All the students have had access to the online resources; some students have used them, but some have not. Data on student expectations collected prior to starting on the module are compared with student feedback gathered at the end of the module and student performance data across the two mode's of presentation are compared to establish the relative effectiveness of each approach. In addition the paper reviews the resource implications of developing, delivering and supporting online learning and discusses some of the barriers to implementation that were encountered and overcome

    A Complete Atlas of HI Absorption toward HII Regions in the Southern Galactic Plane Survey (SGPS1)

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    We present a complete catalog of H I emission and absorption spectrum pairs, toward H II regions, detectable within the boundaries of the Southern Galactic Plane Survey (SGPS I), a total of 252 regions. The catalog is presented in graphical, numerical and summary formats. We demonstrate an application of this new dataset through an investigation of the locus of the Near 3kpc Arm.Comment: Accepted for publication by ApJS Feb 6, 2014. Data files and Figure Set (252 images) to appear in the on-line version of the journa
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