51,900 research outputs found

    Connectivism: Its place in theory-informed research and innovation in technology-enabled learning

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    The sociotechnical context for learning and education is dynamic and makes great demands on those trying to seize the opportunities presented by emerging technologies. The goal of this paper is to explore certain theories for our plans and actions in technology-enabled learning. Although presented as a successor to previous learning theories, connectivism alone is insufficient to inform learning and its support by technology in an internetworked world. However, because of its presence in massive open online courses (MOOCs), connectivism is influential in the practice of those who take these courses and who wish to apply it in teaching and learning. Thus connectivism is perceived as relevant by its practitioners but as lacking in rigour by its critics. Five scenarios of change are presented with frameworks of different theories to explore the variety of approaches educators can take in the contexts for change and their associated research/evaluation. I argue that the choice of which theories to use depends on the scope and purposes of the intervention, the funding available to resource the research/evaluation, and the experience and philosophical stances of the researchers/practitioners

    The evolving disk galaxy population

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    In this contribution, I present a simplified overview of the evolution of the disk galaxy population since z=1, and a brief discussion of a few open questions. Galaxy evolution surveys have found that the disk galaxy population forms stars intensely at intermediate redshift. In particular, they dominate the cosmic star formation rate at z<1 -- the factor of ten drop in cosmic average comoving star formation rate in the last 8 Gyr is driven primarily by disk physics, not by a decreasing major merger rate. Despite this intense star formation, there has been little change in the stellar mass density in disk galaxies since z=1; large numbers of disk galaxies are being transformed into non-star-forming spheroid-dominated galaxies by galaxy interactions, AGN feedback, environmental effects, and other physical processes. Finally, despite this intense activity, the scaling relations of disk galaxies appear to evolve little. In particular, as individual galaxies grow in mass through the formation of stars, they appear to grow in radius (on average, the population grows inside-out), and they appear to evolve towards somewhat higher rotation velocity (i.e., mass is added at both small and large radii during this inside-out growth).Comment: Invited Review at the Vatican Symposium: Formation and Evolution of Galaxy Disks, October 2007, proceeding editors Jose G. Funes, SJ and Enrico M. Corsin

    How Magnetic is the Neutrino?

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    The existence of a neutrino magnetic moment implies contributions to the neutrino mass via radiative corrections. We derive model-independent "naturalness" upper bounds on the magnetic moments of Dirac and Majorana neutrinos, generated by physics above the electroweak scale. For Dirac neutrinos, the bound is several orders of magnitude more stringent than present experimental limits. However, for Majorana neutrinos the magnetic moment bounds are weaker than present experimental limits if μν\mu_\nu is generated by new physics at ~ 1 TeV, and surpass current experimental sensitivity only for new physics scales > 10 -- 100 TeV. The discovery of a neutrino magnetic moment near present limits would thus signify that neutrinos are Majorana particles.Comment: 9 pages, 6 figures. Talk given at Festschrift in honour of B. H. J McKellar and G. C. Josh

    YouTube as a repository : the creative practice of students as producers of Open Educational Resources

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    In this paper we present an alternative view of Open Educational Resources (OERs). Rather than focusing on open media resources produced by expert practitioners for use by peers and learners, we examine the practice of learners as active agents, producing open media resources using the devices in their pockets: their mobile phones. In this study, students are the producers and operate simultaneously as legitimate members of the YouTube community and producers of educational content for future cohorts. Taking an Action Research approach we investigated how student’s engagement with open media resources related to their creativity. Using Kleiman’s framework of fives conceptual themes which emerged from academics experiences of creativity (constraint, process, product, transformation, fulfillment), we found that these themes revealed the opportunities designed into the assessed task and provided a useful lens with which to view students’ authentic creative experiences. Students’ experience of creativity mapped on to Kleiman’s framework, and was affected by assessment. Dimensions of openness changed across platforms, although the impact of authenticity and publication on creativity was evident, and the production of open media resources that have a dual function as OERs has clear benefits in terms of knowledge sharing and community participation.The transformational impacts for students were evident in the short term but would merit a longitudinal study. A series of conclusions are drawn to inform future practice and research

    Implications of asteroid composition for the geochemistry of the ancient terrestrial projectile flux

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    The discovery of enhanced siderophile abundances at the Cretaceous/Tertiary boundary has provoked many searches for geochemical signatures which could reveal other catastrophic impacts in Earth's history. These searches implicitly assume that most large impactors are of chondritic, iron, or stony-iron composition, with a greatly enhanced abundance of siderophile elements. Impactors composed of asteroidal crust or mantle rocks analogous to the achondritic meteorites would not leave a distinct geochemical trace since their siderophile abundances are grossly similar to those of the Earth's crust. In recent years studies of the mineralogical composition of the current asteroid belt have suggested that the composition of impacting projectiles may be highly variable with both projectile size and time. In particular it seems possible that in the distant past projectiles derived from asteroid mantle material may have caused a large fraction of the cratering events on Earth. Such impacts would be missed by any geochemical search relying on iridium or any other siderophile element. The questions of the effect of size and time variations on projectile composition and the significance of hidden impacts missing in current geochemical searches are examined
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