Browsing by Subject "field"
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- ItemOpen AccessDistinguishing the field of educational technology(Academic Publishing Limited, 2008) Czerniewicz, LauraDrawing on what researchers and professionals in the field internationally report, this paper reviews educational technology as an emergent field. The review reveals the continuum of perspectives on what the field is, and how it is bounded or fragmented. The paper describes the field from two perspectives: the professional and scholarly and considers how the forms of knowledge differ and overlap in each domain. It posits some dichotomies which may frame the field such as science/social science and positivist/post-modernist. Finally the paper provides conceptual frameworks for distinguishing fields from each other and suggests what the categorisation of the field might mean, especially considering its emergent status in a rapidly changing context.
- ItemOpen AccessEducational technology - mapping the terrain with Bernstein as cartographer(Blackwell Publishing Ltd, 2010) Czerniewicz, LauraThis paper uses the literature of educational technology as the site of analysis in order to map the field of educational technology. Having considered Kuhn and Bourdieu's theories, the paper frames the analysis of the field in Bernsteinian terms as a horizontal knowledge structure in a vertical knowledge discourse. Using the concepts of interacting discursive planes, the paper maps the field in terms of its general approach planes and its problem planes. Finally, the paper shows that researchers in the field themselves acknowledge its weak grammar, and calls for commensurability of approaches to be acknowledged in order for robust knowledge to be developed and the legitimacy of the field to be enhanced.
- ItemOpen AccessH i kinematics, mass distribution and star formation threshold in NGC 6822, using the SKA pathfinder KAT-7(2017) Namumba, B; Carignan, C; Passmoor, S; de Blok, W J GWe present high sensitivity H I observations of NGC 6822, obtained with the Karoo Array Telescope (KAT-7). We study the kinematics, the mass distribution and the star formation thresholds. The KAT-7 short baselines and low system temperature make it sensitive to large-scale, low surface brightness emission. The observations detected ∼ 23 per cent more flux than previous Australian Telescope Compact Array observations. We fit a tilted ring model to the H I velocity field to derive the rotation curve (RC). The KAT-7 observations allow the measurement of the rotation curve of NGC 6822 out to 5.8 kpc, ∼1 kpc further than existing measurements. NGC 6822 is seen to be dark matter dominated at all radii. The observationally motivated pseudo-isothermal dark matter (DM) halo model reproduces well the observed RC while the Navarro Frank-White DM model gives a poor fit to the data. We find the best-fitting mass-to-light ratio (M/L) of 0.12 ± 0.01 which is consistent with the literature. The modified Newtonian dynamics gives a poor fit to our data. We derive the star formation threshold in NGC 6822 using the H I and H α data. The critical gas densities were calculated for gravitational instabilities using the Toomre-Q criterion and the cloud-growth criterion. We found that in regions of star formation, the cloud-growth criterion explains star formation better than the Toomre-Q criterion. This shows that the local shear rate could be a key player in cloud formation for irregular galaxies such as NGC 6822.
- ItemOpen AccessThe LOFAR Two-metre Sky Survey: I. Survey description and preliminary data release⋆(2017) Shimwell, T W; Röttgering, H J A; Best, P N; Williams, W L; Dijkema, T J; de Gasperin, F; Hardcastle, M J; Heald, G H; Hoang, D N; Horneffer, A; Intema, H; Mahony, E K; Mandal, S; Mechev, A P; Morabito, L; Oonk, J B R; Rafferty, D; Retana-Montenegro, E; Sabater, J; Tasse, C; van Weeren, R J; BrYggen, M; Brunetti, G; Chyży, K T; Conway, J E; Haverkorn, M; Jackson, N; Jarvis, M J; McKean, J P; Miley, G K; Morganti, R; White, G J598