16,266 research outputs found
Probing The Lower Mass Limit For Supernova Progenitors And The High-Mass End Of The Initial-Final Mass Relation From White Dwarfs In The Open Cluster M35 (NGC 2168)
We present a photometric and spectroscopic study of the white dwarf (WD) population of the populous, intermediate-age open cluster M35 (NGC 2168); this study expands upon our previous study of the WDs in this cluster. We spectroscopically confirm 14 WDs in the field of the cluster: 12 DAs, 1 hot DQ, and 1 db star. For each DA, we determine the WD mass and cooling age, from which we derive each star's progenitor mass. These data are then added to the empirical initial-final mass relation (IFMR), where the M35 WDs contribute significantly to the high-mass end of the relation. The resulting points are consistent with previously published linear fits to the IFMR, modulo moderate systematics introduced by the uncertainty in the star cluster age. Based on this cluster alone, the observational lower limit on the maximum mass of WD progenitors is found to be similar to 5.1M(circle dot) - 5.2M(circle dot) at the 95% confidence level; including data from other young open clusters raises this limit to as high as 7.1M(circle dot), depending on the cluster membership of three massive WDs and the core composition of the most massive WDs. We find that the apparent distance modulus and extinction derived solely from the cluster WDs ((m-M)(V) = 10.45 +/- 0.08 and E(B-V) = 0.185 +/- 0.010, respectively) is fully consistent with that derived from main-sequence fitting techniques. Four M35 WDs may be massive enough to have oxygen - neon cores; the assumed core composition does not significantly affect the empirical IFMR. Finally, the two non-DA WDs in M35 are photometrically consistent with cluster membership; further analysis is required to determine their memberships.NSF AST-0397492, AST-0602288Astronom
Methodologies of the Creatively Maladjusted
As intellectuals, artists must actively challenge societal power structures and the accepted way of thinking. Unless authority is questioned and discussed by the masses, the perception of power can segue almost seamlessly into actual power. It is the responsibility of the artist to disrupt these ingrained social systems through the work they create. According to Pablo Helguera, there are two different kinds of socially engaged artwork: the symbolic and the actual. While symbolic artwork focuses more on poetics and connecting with the audience, actual artwork emphasizes the functionality and applicable nature of the art. It is vitally important to blend these two forms of artistic practice. The symbolic form engages the public and evokes a response, while the actual form directs that response towards the physical fulfillment of social needs. There are a number of strategies and methodologies that I engage to address these social travails: context, dissemination, art as a media device, collaboration and the unsanctioned. When creating my own artwork, I take these strategies into careful consideration to most successfully engage the public
Bayesian Analysis for Food-Safety Risk Assessment: Evaluation of Dose-Response Functions within WinBUGS
John Ruskin: conservative attitudes to the modern 1836-1860
I examine the way in which, in his work of the 1840s, Ruskin uses methods and assumptions
derived from eighteenth-century Materialist, Mechanist and Vitalist Natural Philosophy,
especially his assertion that the meanings which he reads into natural phenomena are
objectively present and can be quantified, and the way in which therefore aesthetic concepts,
responses and judgements can be quantified, and their values fixed.
I examine the ways in which Ruskin seeks to demonstrate the relationship between the unity
of Nature and the Multipilicity of Phenomena, not only as existing objectively in the external
world, but also as reflected in the paintings of Turner. I suggest that his attempt at
demonstration features a problematic relationship between his accounting for a material reality
and the spiritual significances which he sees as immanent in it, and that resistance to the
dynamism of contemporary industrial and social change is implicit in his celebration of an
eternalised natural order.
I examine four features of his correspondence during the 1840s: his dealings in the art
market, his outright opposition to a number of modern developments, his urgent desires to
see his favourite European architectural heritage preserved, and his strident xenophobia, and
suggest relationships between the last two and his resistance to the modern.
I examine the shift in his interests in the 1840s and 1850s from Nature and Art to
Architecture and Man, and thence to Political Economy, and examine available accounts
which rely too heavily on references to his psychological development, or on his claims to
regular epiphanies, or on a significant shift in focus which can be explained by revealing the
internal continuities in his work.
I conclude with an attempt to demonstrate that what I have called the "broad sweep" approach
obscures the confusions and contradictions in his position in the late 1840s and 1850s, and
suggest that his social and intellectual inheritance, which is of a highly conservative and
unremittingly paternalistic nature, crucially limits his work as ~ social critic.
I offer three appendices: on the problem of the relationship between the Unity of Nature and
the Multiplicity of Phenomena as that had been addressed in the Natural Philosophy on whose
assumptions Ruskin draws; on eighteenth century Materialist, Mechanist and Vitalist theories
of matter; and on the work of Edmund Burke and Sir Charles Bell
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