32,272 research outputs found
Narratives from YouTube: Juxtaposing stories about physical education
The aim of this paper is to explore what is performed in students’ and teachers’ actions in physical education practice in terms of “didactic irritations,” through an analysis of YouTube clips from 285 PE lessons from 27 different countries. Didactic irritations are occurrences that Rønholt describes as those demanding “didactic, pedagogical reflections and discussions, which in turn could lead to alternative thinking and understanding about teaching and learning.” Drawing on Barad’s ideas of performativity to challenge our habitual anthropocentric analytical gaze when looking at educational visual data, and using narrative construction, we also aim to give meaning to actions, relations, and experiences of the participants in the YouTube clips. To do this, we present juxtaposing narratives from teachers and students in terms of three “didactic irritations”: (a) stories from a track, (b), stories from a game, and (c), stories from a bench. The stories re-present events-of-moving in the data offering insights into embodied experiences in PE practice, making students’ as well as teachers’ actions in PE practice understandable
Cosmological Conductive/Cooling Fronts as Lyman Alpha Forest Clouds
We propose a simple model for the origin and evolution of \lya clouds based
on cosmological conductive/cooling fronts. In this model the \lya arises in the
interfaces between the IGM and cold clouds that could be tentatively identified
with protogalaxies. Most of the properties of the \lya absorbers are reproduced
with a very restricted number of assumptions. Among these are the correct range
of HI column density, cloud sizes and redshift and HI column density
distributions for the absorbers. Several predictions and implications of the
model are briefly discussed.Comment: 9 pages, plain TeX, 3 figures; ApJ Letters, accepte
Notes on drift theory
It is shown that there is a simpler way to derive the average guiding center drift of a distribution of particles than via the so-called single particle analysis. Based on this derivation it is shown that the entire drift formalism can be considerably simplified, and that results for low order anisotropies are more generally valid than is usually appreciated. This drift analysis leads to a natural alternative derivation of the drift velocity along a neutral sheet
Review of deaths related to taking ecstasy, England and Wales, 1997-2000
Original article can be found at: http://www.bmj.com/archive/--Copyright BMJ Publishing Group Ltd DOI : 10.1136/bmj.326.7380.80Peer reviewe
The gaseous extent of galaxies and the origin of Lyman alpha absorption systems. IV: Lyman alpha absorbers arising in a galaxy group
We present new GHRS observations of Lyman alpha absorption lines associated
with a group of galaxies towards the QSO 1545+2101. We have identified eight
distinct Lyman alpha absorption features in the spectrum of QSO 1545+2101 at a
mean redshift of z=0.2648 with a velocity dispersion of 163 km/s. A group of
galaxies is detected in the vicinity of this QSO at a mean redshift of z=0.2645
and velocity dispersion 239 km/s.
The identification of discrete absorption systems indicates that they arise
in clouds of neutral hydrogen rather than in a diffuse intragroup medium. Our
analysis suggests that the Lyman alpha absorption lines are associated with
individual galaxies in the group, although a one-to-one relationship between
absorbers and galaxies is difficult to establish in such a dense environment.Comment: 16 pages, 3 figures. Accepted for publication in Ap
Diffusive electron acceleration at SNR shock fronts and the observed SNR radio spectral indices
The radio synchrotron emission from relativistic electrons in shell supernova remnants (SNRs) provides a unique opportunity to probe the energy distribution of energetic electrons at their acceleration site (SNR shock fronts). This information provides insight into the acceleration mechanism(s). The implications of these observations for the diffusive (first-order Fermi) acceleration of electrons at the SNR shock fronts are discussed
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