43,204 research outputs found
“Three Cheers for Earl Haig”: Canadian Veterans and the Visit of Field Marshal Sir Douglas Haig to Canada in the Summer of 1925
Eyewitness to Jesus: amazing new manuscript evidence about the origin of the Gospels
Reviewed Book: Thiede, Carsten Peter. Eyewitness to Jesus: amazing new manuscript evidence about the origin of the Gospels. New York: Doubleday, 1996
Sociology and Its Others: Reflections on Disciplinary Specialisation and Fragmentation
[No abstract][No keywords]
Connectivism: a knowledge learning theory for the digital age?
<b>Background</b> The emergence of the internet, particularly Web 2.0 has provided access to the views and opinions of a wide range of individuals opening up opportunities for new forms of communication and knowledge formation. Previous ways of navigating and filtering available information are likely to prove ineffective in these new contexts. Connectivism is one of the most prominent of the network learning theories which have been developed for e-learning environments. It is beginning to be recognised by medical educators. This paper aims to examine connectivism and its potential application.<p></p>
<b>Content</b> The conceptual framework and application of connectivism are presented along with an outline of the main criticisms. Its’ potential application in medical education is then considered.<p></p>
<b>Conclusions</b> While connectivism provides a useful lens through which teaching and learning using digital technologies can be better understood and managed, further development and testing is required. There is unlikely to be a single theory that will explain learning in technological enabled networks. Educators have an important role to play in online network learning
Rates of tidal disruption of stars by massive central black holes
There is strong evidence for some kind of massive dark object in the centres
of many galaxy bulges. The detection of flares from tidally disrupted stars
could confirm that these objects are black holes (BHs). Here we present
calculations of the stellar disruption rates in detailed dynamical models of
real galaxies, taking into account the refilling of the loss cone of stars on
disruptable orbits by two-body relaxation and tidal forces in non-spherical
galaxies. The highest disruption rates (one star per 10^4 yr) occur in faint
(L>10^10 L_sun) galaxies, which have steep central density cusps. More luminous
galaxies are less dense and have much longer relaxation times and more massive
BHs. Dwarf stars in such galaxies are swallowed whole by the BH and hence do
not emit flares; giant stars could produce flares as often as every 10^5 yr,
although the rate depends sensitively on the shape of the stellar distribution
function. We discuss the possibility of detecting disruption flares in current
supernova searches. The total mass of stars consumed over the lifetime of the
galaxy is of order 10^6 M_sun, independent of galaxy luminosity; thus disrupted
stars may contribute significantly to the present BH mass in galaxies fainter
than about 10^9 L_sun.Comment: 14 pages, 5 figures, 1 landscape table. Submitted to MNRA
- …