961 research outputs found
How do you spell 'support'? Multiple methods of library support to distributed education programs
This paper consists of librarians from two universities, one in the US and one in Canada, discussing and demonstrating the various ways they offer support to multiple distributed education programs. Because different programs on the same campus often offer distributed courses in different formats, libraries are required to become expert in all formats offered. This presentation will discuss library support via WebCT, Blackboard, FirstClass, proprietary courseware, email, the web, and Conferencing software. Where appropriate, differences between library support in the US and Canada will be noted and examined
A Review of Action Research in Teaching and Learning: A Practical Guide to Conducting Pedagogical Research in Universities
Action Research in Teaching and Learning: A Practical Guide to Conducting Pedagogical Research in Universities by Lynn S. Norton provides a useful resource for those in higher education interested in using action research. Action research takes place when educational practitioners reflect on their approach to education and test pedagogical theories with research that is then presented for consideration within the institution and in the wider academic arena. After making a case for the use of action research as an important part of the scholarship of teaching and learning that should take place in higher education, the author discusses the steps for conducting action research— from identifying the problem to addressing quantitative and qualitative research approaches and publishing the results
Supernovae and their expanding blast waves during the early evolution of Galactic globular clusters
Our arguments deal with the early evolution of Galactic globular clusters and
show why only a few of the supernovae products were retained within globular
clusters and only in the most massive cases ( Msol), while less
massive clusters were not contaminated at all by supernovae. Here we show that
supernova blast waves evolving in a steep density gradient undergo blowout and
end up discharging their energy and metals into the medium surrounding the
clusters. This inhibits the dispersal and the contamination of the gas left
over from a first stellar generation. Only the ejecta from well centered
supernovae, that evolve into a high density medium available for a second
stellar generation in the most massive clusters would be retained. These are
likely to mix their products with the remaining gas, leading in these cases
eventually to an Fe contaminated second stellar generation.Comment: Accepted for publication in the Astrophysical Journal Letters,
10pages, 1 figur
The realm of the Galactic globular clusters and the mass of their primordial clouds
By adopting the empirical constraints related to the estimates of Helium
enhancement (), present mass ratio between first and second stellar
generations () and the actual mass of Galactic globular clusters
(), we envisage a possible scenario for the formation of these stellar
systems. Our approach allows for the possible loss of stars through evaporation
or tidal interactions and different star formation efficiencies. In our
approach the star formation efficiency of the first generation
() is the central factor that links the stellar generations as
it not only defines both the mass in stars of the first generation and the
remaining mass available for further star formation, but it also fixes the
amount of matter required to contaminate the second stellar generation. In this
way, is fully defined by the He enhancement between successive
generations in a GC. We also show that globular clusters fit well within a
{\it vs} diagram which indicates three different
evolutionary paths. The central one is for clusters that have not loss stars,
through tidal interactions, from either of their stellar generations, and thus
their present value is identical to the amount of low mass stars ( 1 M) that resulted from both stellar generations. Other possible
evolutions imply either the loss of first generation stars or the combination
of a low star formation efficiency in the second stellar generation and/or a
loss of stars from the second generation. From these considerations we derive a
lower limit to the mass () of the individual primordial clouds that
gave origin to globular clusters.Comment: 17 pages, 2 figures, accepted for publication in the Astrophysical
Journa
Star Formation in Tadpole Galaxies
Tadpole Galaxies look like a star forming head with a tail structure to the
side. They are also named cometaries. In a series of recent works we have
discovered a number of issues that lead us to consider them extremely
interesting targets. First, from images, they are disks with a lopsided
starburst. This result is firmly established with long slit spectroscopy in a
nearby representative sample. They rotate with the head following the rotation
pattern but displaced from the rotation center. Moreover, in a search for
extremely metal poor (XMP) galaxies, we identified tadpoles as the dominant
shapes in the sample- nearly 80% of the local XMP galaxies have a tadpole
morphology. In addition, the spatially resolved analysis of the metallicity
shows the remarkable result that there is a metallicity drop right at the
position of the head. This is contrary to what intuition would say and
difficult to explain if star formation has happened from gas processed in the
disk. The result could however be understood if the star formation is driven by
pristine gas falling into the galaxy disk. If confirmed, we could be unveiling,
for the first time, cool flows in action in our nearby world. The tadpole class
is relatively frequent at high redshift - 10% of resolvable galaxies in the
Hubble UDF but less than 1% in the local Universe. They are systems that could
track cool flows and test models of galaxy formation.Comment: arXiv admin note: text overlap with arXiv:1302.435
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