8,508 research outputs found

    The Kinematics of CIV in Star-Forming Galaxies at z~1.2

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    We present the first statistical sample of rest-frame far-UV spectra of star-forming galaxies at z~1. These spectra are unique in that they cover the high-ionization CIV{\lambda}{\lambda}1548, 1550 doublet. We also detect low-ionization features such as SiII{\lambda}1527, FeII{\lambda}1608, AlII{\lambda}1670, NiII{\lambda}{\lambda}1741, 1751 and SiII{\lambda}1808, and intermediate-ionization features from AlIII{\lambda}{\lambda}1854, 1862. Comparing the properties of absorption lines of lower- and higher- ionization states provides a window into the multi-phase nature of circumgalactic gas. Our sample is drawn from the DEEP2 survey and spans the redshift range 1.01 < z < 1.35 ( = 1.25). By isolating the interstellar CIV absorption from the stellar P-Cygni wind profile we find that 69% of the CIV profiles are blueshifted with respect to the systemic velocity. Furthermore, CIV shows a small but significant blueshift relative to FeII (offset of the best-fit linear regression -76 ±\pm 26 km/s). At the same time, the CIV blueshift is on average comparable to that of MgII{\lambda}{\lambda}2796, 2803. At this point, in explaining the larger blueshift of CIV absorption at the ~ 3-sigma level, we cannot distinguish between the faster motion of highly-ionized gas relative to gas traced by FeII, and filling in on the red side from resonant CIV emission. We investigate how far-UV interstellar absorption kinematics correlate with other galaxy properties using stacked spectra. These stacking results show a direct link between CIV absorption and the current SFR, though we only observe small velocity differences among different ionization states tracing the outflowing ISM.Comment: 21 pages, 14 figures, ApJ, accepte

    Using learning design as a framework for supporting the design and reuse of OER

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    The paper will argue that adopting a learning design methodology may provide a vehicle for enabling better design and reuse of Open Educational Resources (OERs). It will describe a learning design methodology, which is being developed and implemented at the Open University in the UK. The aim is to develop a 'pick and mix' learning design toolbox of different resources and tools to help designers/teachers make informed decisions about creating new or adapting existing learning activities. The methodology is applicable for designers/teachers designing in a traditional context – such as creation of materials as part of a formal curriculum, but also has value for those wanting to create OERs or adapt and repurpose existing OERs. With the increasing range of OERs now available through initiatives as part of the Open Courseware movement, we believe that methodologies, such as the one we describe in this paper, which can help guide reuse and adaptation will become increasingly important and arguably are an important aspect of ensuring longer term sustainability and uptake of OERs. Our approach adopts an empirically based approach to understanding and representing the design process. This includes a range of evaluation studies (capturing of case studies, interviews with designers/teachers, in-depth course evaluation and focus groups/workshops), which are helping to develop our understanding of how designers/teachers go about creating new learning activities. Alongside this we are collating an extensive set of tools and resources to support the design process, as well as developing a new Learning Design tool that helps teachers articulate and represent their design ideas. The paper will describe how we have adapted a mind mapping and argumentation tool, Compendium, for this purpose and how it is being used to help designers and teachers create and share learning activities. It will consider how initial evaluation of the use of the tool for learning design has been positive; users report that the tool is easy to use and helps them organise and articulate their learning designs. Importantly the tool also enables them to share and discuss their thinking about the design process. However it is also clear that visualising the design process is only one aspect of design, which is complex and multi-faceted
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