2,476 research outputs found

    The world-swimmers

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    This thesis has two main parts. The first comprises a collection of nineteen short stories, entitled The World-Swimmers. The second takes the form of an exegesis, \u27Framing Fictions & Fictional Friendships,\u27 which provides a critical commentary on the collection, and on the nexus of text and context. The stories vary in length from approximately 1,000 to over 4,000 words. Various writing styles are used to develop fictional explorations of a range of themes, which include: the relationship between the natural and the human worlds, the imbrication of local place and international space, obsession, entrapment, and desire. However, perhaps the most salient theme is that of the continuous interplay between ideas and daily life. The exegesis begins with a consideration of the concept of the artistic frame. A general theoretical analysis of framing, inspired by the chapter \u27Parergon\u27 in Jacques Derrida\u27s The Truth in Painting, provides an anchor for more particular speculations about a few of the frames, no doubt actually many in number, which close over the unstable boundary of The World-Swimmers. The exegesis also argues that friendship-especially in its non-intuitive Forms-constitutes a stimulating \u27matrix of thought\u27 for considering the relationships that my collection has, to its thematic concerns, to the fiction of Jorge Luis Borges, and to certain literary genres. I suggest that The World- Swimmers is primarily a magical-realist text, which nevertheless presents many of the traits of postmodern writing

    The Dancing Between Two Worlds Project: Background, Methodology and Learning to Approach Community in Place

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    This article recounts the history to date of the Dancing Between Two Worlds (DBTW) project, which was initiated by a team of artist-scholars at Deakin University in 2018. DBTW’s brief was to engage the Indian community living in the western fringes of Melbourne in a project on civic belonging, cross-cultural artistic identity, and the performance of outer-suburban Indian diaspora. Working with the creative and community energies that are activated at the intersection of the creative arts and demographically inflected place, the Deakin researchers collaborated with local artists with an Indian background on a major performance in late 2019: Dancing Between 2 Worlds. This performance came out of a series of creative exchanges in community venues and public spaces in the City of Wyndham Local Government Area (LGA), whereby the Deakin team offered contemporary ‘Western’ creative approaches and the Indian artists shared their traditional artistic practices—amidst discussions about place, belonging and identity. This process was supplemented by interviews with some of the participants. Our article contextualizes the DBTW project through a summary of two previous, similar Deakin enterprises; looks at the significant methodological issues linked to the project; describes the performance of late 2019; and uses project images and other figures to relate its story. We also take this opportunity to consider the nexus of a practice-led research project with community: that is, the relationships and liaison between institution (Deakin University), local government, participants, and place—over time. The article concludes by digging in to the discursive tension between the terms ‘project’ and ‘group’ and (provisionally) resolves this tension in favour of the ongoing use of the word ‘project’ for DBTW. In this way, we add to the ideas on the ‘rhetoric of projects’ originally expressed by Paul Carter in Material Thinking. The latter section of the article draws on interview material to give voice to the local Indian community members and artists around the developing thematic preoccupations of DBTW, comprising civic belonging, cross-cultural artistic identity, and the performance of Indian diaspora in outer suburban Melbourne. The focus of this article, however, concerns the learning curve at Deakin University that indexes the development of its approach to community in place

    The ACS Virgo Cluster Survey XV. The Formation Efficiencies of Globular Clusters in Early-Type Galaxies: The Effects of Mass and Environment

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    The fraction of stellar mass contained in globular clusters (GCs), also measured by number as the specific frequency, is a fundamental quantity that reflects both a galaxy's early star formation and its entire merging history. We present specific frequencies, luminosities, and mass fractions for the globular cluster systems of 100 early-type galaxies in the ACS Virgo Cluster Survey, the largest homogeneous catalog of its kind. We find that 1) GC mass fractions can be high in both giants and dwarfs, but are universally low in galaxies with intermediate luminosities. 2) The behavior of specific frequency across galaxy mass is dominated by the blue GCs. 3) The GC fractions of low-mass galaxies exhibit a dependence on environment. Nearly all dwarf galaxies with high GC fractions are within 1 Mpc of the cD galaxy M87, presenting the first strong evidence that GC formation in dwarfs is biased toward dense environments. 4) GC formation in central dwarfs is biased because their stars form earliest and most intensely. Comparisons to the Millennium Simulation show that central dwarfs have older stellar populations and form more stars at higher star formation rates (SFRs) and SFR surface densities. The SFR surface density in simulated dwarfs peaks before the total SFR, naturally producing GC populations that are older and more metal-poor than the field stars. 5) Dwarfs within ~40 kpc of the giant ellipticals M87 and M49 are red and have few or no GCs, suggesting that they have been tidally stripped and have contributed their GCs to the halos of their giant neighbors. The central dwarfs with high GC mass fractions are thus likely to be the survivors most similar to the protogalaxies that assembled the rich M87 globular cluster system.(Abridged)Comment: 27 pages, 21 figures, 7 tables. Accepted for publication in the Astrophysical Journa

    The ACS Fornax Cluster Survey. II. The Central Brightness Profiles of Early-Type Galaxies: A Characteristic Radius on Nuclear Scales and the Transition from Central Luminosity Deficit to Excess

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    We analyse HST surface brightness profiles for 143 early-type galaxies in the Virgo and Fornax Clusters. Sersic models provide accurate descriptions of the global profiles with a notable exception: the observed profiles deviate systematically inside a characteristic "break" radius of R_b ~ 0.02R_e where R_e is the effective radius of the galaxy. The sense of the deviation is such that bright galaxies (M_B < -20) typically show central light deficits with respect to the inward extrapolation of the Sersic model, while the great majority of low- and intermediate-luminosity galaxies (-19.5 < M_B < -15) show central light excesses; galaxies occupying a narrow range of intermediate luminosities (-20 < M_B < -19.5) are usually well fitted by Sersic models over all radii. The slopes of the central surface brightness profiles, when measured at fixed fractions of R_e, vary smoothly as a function of galaxy luminosity in a manner that depends sensitively on the choice of measurement radius. We show that a recent claim of strong bimodality in slope is likely an artifact of the galaxy selection function used in that study. To provide a more robust characterization of the inner regions of galaxies, we introduce a parameter that describes the central luminosity deficit or excess relative to the inward extrapolation of the outer Sersic model. We find that this parameter varies smoothly over the range of ~ 720 in blue luminosity spanned by the Virgo and Fornax sample galaxies, with no evidence for a dichotomy. We argue that the central light excesses (nuclei) in M_B > -19 galaxies may be the analogs of the dense central cores that are predicted by some numerical simulations to form via gas inflows. (ABRIDGED)Comment: To appear in the Astrophysical Journal, December 2007. Full resolution paper available at http://www.cfa.harvard.edu/~ajordan/ACSFCS/Home.htm

    Towards a "non-didactic didacticism" of the sociopolitical: assemblages and the event in surface tension and shame

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    To write sociopolitical fiction is to be caught in an odd double bind. The term itself, &lsquo;sociopolitical&rsquo; (hyphenated or not), implies an &lsquo;assemblage&rsquo;, and the terms it combines&mdash;&lsquo;the social&rsquo; and &lsquo;the political&rsquo;&mdash;each suggest complex, worldly assemblages. However, the more the writer attempts to express the assembled complexity of the sociopolitical domain, the more he/she feels a tug in the other direction: towards the version of ideas that might best explain the sociopolitical world and motivate political action. This article engages with the aesthetic and political challenges that arise in writing within a genre in which, to some extent at least, a moral content is desired by readers as an explanation for sociopolitical issues, only to be resisted when, as it often does, it becomes didactic. Co-author Cathryn Perazzo&rsquo;s sociopolitical novel-in-progress, Surface Tension, is, we suggest, a laboratory of an assemblage in action. In it, we test and elaborate our hypothesis of the &lsquo;assembled idea&rsquo; or &lsquo;assembled morality&rsquo; of the sociopolitical novel. We conclude with a look at a published short story, &lsquo;Shameʼ, by co-author Patrick West, which similarly deals with the sociopolitical, with how &lsquo;non-didactic didacticisms&rsquo; might be germinated, and, most explicitly, with the &lsquo;event&rsquo;, following Deleuze&rsquo;s use of this term

    The ACS Virgo Cluster Survey II. Data Reduction Procedures

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    The ACS Virgo Cluster Survey is a large program to carry out multi-color imaging of 100 early-type members of the Virgo Cluster using the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. Deep F475W and F850LP images (~ SDSS g and z) are being used to study the central regions of the program galaxies, their globular cluster systems, and the three-dimensional structure of Virgo itself. In this paper, we describe in detail the data reduction procedures used for the survey, including image registration, drizzling strategies, the computation of weight images, object detection, the identification of globular cluster candidates, and the measurement of their photometric and structural parameters.Comment: 33 pages, 8 figures. Accepted for publication in ApJS. Also available at http://www.physics.rutgers.edu/~pcote/acs/publications.htm

    Trends in the Globular Cluster Luminosity Function of Early-Type Galaxies

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    We present results from a study of the globular cluster luminosity function (GCLF) in a sample of 89 early-type galaxies observed as part of the ACS Virgo Cluster Survey. Using a Gaussian parametrization of the GCLF, we find a highly significant correlation between the GCLF dispersion, sigma, and the galaxy luminosity, M_B, in the sense that the GC systems in fainter galaxies have narrower luminosity functions. The GCLF dispersions in the Milky Way and M31 are fully consistent with this trend, implying that the correlation between sigma and galaxy luminosity is more fundamental than older suggestions that GCLF shape is a function of galaxy Hubble type. We show that the sigma - M_B relation results from a bonafide narrowing of the distribution of (logarithmic) cluster masses in fainter galaxies. We further show that this behavior is mirrored by a steepening of the GC mass function for relatively high masses, M >~ 3 x 10^5 M_sun, a mass regime in which the shape of the GCLF is not strongly affected by dynamical evolution over a Hubble time. We argue that this trend arises from variations in initial conditions and requires explanation by theories of cluster formation. Finally, we confirm that in bright galaxies, the GCLF "turns over" at the canonical mass scale of M_TO ~ 2 x 10^5 M_sun. However, we find that M_TO scatters to lower values (~1-2 x 10^5 M_sun) in galaxies fainter than M_B >~ -18.5, an important consideration if the GCLF is to be used as a distance indicator for dwarf ellipticals.Comment: 4 pages, 3 figures. Accepted for publication in ApJ Letters. Also available at http://www.cadc.hia.nrc.gc.ca/community/ACSVCS/publications.htm

    Aerosol influence on energy balance of the middle atmosphere of Jupiter

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    Aerosols are ubiquitous in planetary atmospheres in the Solar System. However, radiative forcing on Jupiter has traditionally been attributed to solar heating and infrared cooling of gaseous constituents only, while the significance of aerosol radiative effects has been a long-standing controversy. Here we show, based on observations from the NASA spacecraft Voyager and Cassini, that gases alone cannot maintain the global energy balance in the middle atmosphere of Jupiter. Instead, a thick aerosol layer consisting of fluffy, fractal aggregate particles produced by photochemistry and auroral chemistry dominates the stratospheric radiative heating at middle and high latitudes, exceeding the local gas heating rate by a factor of 5–10. On a global average, aerosol heating is comparable to the gas contribution and aerosol cooling is more important than previously thought. We argue that fractal aggregate particles may also have a significant role in controlling the atmospheric radiative energy balance on other planets, as on Jupiter

    The ACS Virgo Cluster Survey IV: Data Reduction Procedures for Surface Brightness Fluctuation Measurements with the Advanced Camera for Surveys

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    The Advanced Camera for Surveys (ACS) Virgo Cluster Survey is a large program to image 100 early-type Virgo galaxies using the F475W and F850LP bandpasses of the Wide Field Channel of the ACS instrument on the Hubble Space Telescope (HST). The scientific goals of this survey include an exploration of the three-dimensional structure of the Virgo Cluster and a critical examination of the usefulness of the globular cluster luminosity function as a distance indicator. Both of these issues require accurate distances for the full sample of 100 program galaxies. In this paper, we describe our data reduction procedures and examine the feasibility of accurate distance measurements using the method of surface brightness fluctuations (SBF) applied to the ACS Virgo Cluster Survey F850LP imaging. The ACS exhibits significant geometrical distortions due to its off-axis location in the HST focal plane; correcting for these distortions by resampling the pixel values onto an undistorted frame results in pixel correlations that depend on the nature of the interpolation kernel used for the resampling. This poses a major challenge for the SBF technique, which normally assumes a flat power spectrum for the noise. We investigate a number of different interpolation kernels and show through an analysis of simulated galaxy images having realistic noise properties that it is possible, depending on the kernel, to measure SBF distances using distortion-corrected ACS images without introducing significant additional error from the resampling. We conclude by showing examples of real image power spectra from our survey.Comment: ApJS, in press, complete version of the paper at the link: http://www.physics.rutgers.edu/~pcote/acs/publications.htm

    Longitudinal Analysis of Antibody Responses to Trachoma Antigens Before and After Mass Drug Administration.

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    Blinding trachoma, caused by the bacteria Chlamydia trachomatis, is a neglected tropical disease targeted for elimination by 2020. A major component of the elimination strategy is mass drug administration (MDA) with azithromycin. Currently, program decisions are made based on clinical signs of ocular infection, but we have been investigating the use of antibody responses for post-MDA surveillance. In a previous study, IgG responses were detected in children lacking clinical evidence of trachoma, suggesting that IgG responses represented historical infection. To explore the utility of serology for program evaluation, we compared IgG and IgA responses to trachoma antigens and examined changes in IgG and IgA post-drug treatment. Dried blood spots and ocular swabs were collected with parental consent from 264 1-6 year olds in a single village of Kongwa District, central Tanzania. Each child also received an ocular exam for detection of clinical signs of trachoma. MDA was given, and six months later an additional blood spot was taken from these same children. Ocular swabs were analyzed for C. trachomatis DNA and antibody responses for IgA and total IgG were measured in dried bloods spots. Baseline antibody responses showed an increase in antibody levels with age. By age 6, the percentage positive for IgG (96.0%) was much higher than for IgA (74.2%). Antibody responses to trachoma antigens declined significantly six months after drug treatment for most age groups. The percentage decrease in IgA response was much greater than for IgG. However, no instances of seroreversion were observed. Data presented here suggest that focusing on concordant antibody responses in children will provide the best serological surveillance strategy for evaluation of trachoma control programs
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