2,849 research outputs found
Claim your space: re-placing spaces to better meet the needs of the net generation
The challenge for the Reid Library at The University of Western Australia was the transformation of a 1960s building into a welcoming space with services and facilities appropriate for a more technologically demanding generation. A key issue was how to balance the continuing need for access to physical collections with the rapidly expanding demand for new kinds of learning spaces and facilities oriented towards on-line and collaborative learning and research. This paper outlines the approach taken to identify client needs (both physical and virtual), define and propose new service models, and transform learning spaces while maintaining access to physical collections
Microjansky sources at 1.4 GHz
We present a deep 1.4 GHz survey made with the Australia Telescope Compact
Array (ATCA), having a background RMS of 9 microJy near the image phase centre,
up to 25 microJy at the edge of a 50' field of view. Over 770 radio sources
brighter than 45 microJy have been catalogued in the field. The differential
source counts in the deep field provide tentative support for the growing
evidence that the microjansky radio population exhibits significantly higher
clustering than found at higher flux density cutoffs. The optical
identification rate on CCD images is approximately 50% to R=22.5, and the
optical counterparts of the faintest radio sources appear to be mainly single
galaxies close to this optical magnitude limit.Comment: 6 pages, 4 figures, accepted by ApJ Letters 4 May 199
Neural-network selection of high-redshift radio quasars, and the luminosity function at z~4
We obtain a sample of 87 radio-loud QSOs in the redshift range 3.6<z<4.4 by
cross-correlating sources in the FIRST radio survey S{1.4GHz} > 1 mJy with
star-like objects having r <20.2 in SDSS Data Release 7. Of these 87 QSOs, 80
are spectroscopically classified in previous work (mainly SDSS), and form the
training set for a search for additional such sources. We apply our selection
to 2,916 FIRST-DR7 pairs and find 15 likely candidates. Seven of these are
confirmed as high-redshift quasars, bringing the total to 87. The candidates
were selected using a neural-network, which yields 97% completeness (fraction
of actual high-z QSOs selected as such) and an efficiency (fraction of
candidates which are high-z QSOs) in the range of 47 to 60%. We use this sample
to estimate the binned optical luminosity function of radio-loud QSOs at , and also the LF of the total QSO population and its comoving density. Our
results suggest that the radio-loud fraction (RLF) at high z is similar to that
at low-z and that other authors may be underestimating the fraction at high-z.
Finally, we determine the slope of the optical luminosity function and obtain
results consistent with previous studies of radio-loud QSOs and of the whole
population of QSOs. The evolution of the luminosity function with redshift was
for many years interpreted as a flattening of the bright end slope, but has
recently been re-interpreted as strong evolution of the break luminosity for
high-z QSOs, and our results, for the radio-loud population, are consistent
with this.Comment: 20 pages. Accepted for publication in MNRAS on 3 March 201
The Electrodynamics of Inhomogeneous Rotating Media and the Abraham and Minkowski Tensors II: Applications
Applications of the covariant theory of drive-forms are considered for a
class of perfectly insulating media. The distinction between the notions of
"classical photons" in homogeneous bounded and unbounded stationary media and
in stationary unbounded magneto-electric media is pointed out in the context of
the Abraham, Minkowski and symmetrized Minkowski electromagnetic
stress-energy-momentum tensors. Such notions have led to intense debate about
the role of these (and other) tensors in describing electromagnetic
interactions in moving media. In order to address some of these issues for
material subject to the Minkowski constitutive relations, the propagation of
harmonic waves through homogeneous and inhomogeneous, isotropic plane-faced
slabs at rest is first considered. To motivate the subsequent analysis on
accelerating media two classes of electromagnetic modes that solve Maxwell's
equations for uniformly rotating homogeneous polarizable media are enumerated.
Finally it is shown that, under the influence of an incident monochromatic,
circularly polarized, plane electromagnetic wave, the Abraham and symmetrized
Minkowski tensors induce different time-averaged torques on a uniformly
rotating materially inhomogeneous dielectric cylinder. We suggest that this
observation may offer new avenues to explore experimentally the covariant
electrodynamics of more general accelerating media.Comment: 29 pages, 4 figures. Accepted for publication in Proc. Roy. Soc.
Use of neural networks for the identification of new z>=3.6 QSOs from FIRST-SDSS DR5
We aim to obtain a complete sample of redshift > 3.6 radio QSOs from FIRST
sources having star-like counterparts in the SDSS DR5 photometric survey
(r<=20.2). We found that simple supervised neural networks, trained on sources
with SDSS spectra, and using optical photometry and radio data, are very
effective for identifying high-z QSOs without spectra. The technique yields a
completeness of 96 per cent and an efficiency of 62 per cent. Applying the
trained networks to 4415 sources without DR5 spectra we found 58 z>=3.6 QSO
candidates. We obtained spectra of 27 of them, and 17 are confirmed as high-z
QSOs. Spectra of 13 additional candidates from the literature and from SDSS DR6
revealed 7 more z>=3.6 QSOs, giving and overall efficiency of 60 per cent. None
of the non-candidates with spectra from NED or DR6 is a z>=3.6 QSO,
consistently with a high completeness. The initial sample of z>=3.6 QSOs is
increased from 52 to 76, i.e. by a factor 1.46. From the new identifications
and candidates we estimate an incompleteness of SDSS for the spectroscopic
classification of FIRST 3.6<=z<=4.6 QSOs of 15 percent for r<=20.2.Comment: 16 pages, 9 figures accepted for publication in MNRA
An excess of damped Lyman alpha galaxies near QSOs
We present a sample of 33 damped Lyman alpha systems (DLAs) discovered in the
Sloan Digital Sky Survey (SDSS) whose absorption redshifts (z_abs) are within
6000 km/s of the QSO's systemic redshift (z_sys). Our sample is based on 731
2.5 < z_sys < 4.5 non-broad-absorption-line (non-BAL) QSOs from Data Release 3
(DR3) of the SDSS. We estimate that our search is ~100 % complete for absorbers
with N(HI) >= 2e20 cm^-2. The derived number density of DLAs per unit redshift,
n(z), within v < 6000 km/s is higher (3.5 sigma significance) by almost a
factor of 2 than that of intervening absorbers observed in the SDSS DR3, i.e.
there is evidence for an overdensity of galaxies near the QSOs. This provides a
physical motivation for excluding DLAs at small velocity separations in surveys
of intervening 'field' DLAs. In addition, we find that the overdensity of
proximate DLAs is independent of the radio-loudness of the QSO, consistent with
the environments of radio-loud and radio-quiet QSOs being similar.Comment: Accepted for publication in MNRAS (13 pages, 6 figures
The role of symbolic capital in stakeholder disputes: Decision-making concerning intractable wastes
This paper examines almost 30 years of disputation concerning the disposal of the world's largest stockpile of the toxic organochlorine, hexachlorbenzene. It describes the study of a chemicals company in its attempt to manage the disposal of the toxic waste in a collaborative fashion with government, environmentalists and the local community. The study describes the new processes and structures specifically designed to address the decision-making and the issues of stakeholder perception and identity construction which have influenced the outcomes. Decision-making in such disputes is often theorized from the perspective of the emergence of highly individualized and reflexive risk communities and changing modes and expectations of corporate responsibility as a result of detraditionalization. We argue that the stakeholder interaction in this study reflects competing discourses in which corporate actors prioritize the building and maintaining of identity and symbolic capital rather than an active collaboration to solve the ongoing issue of the waste. As well, issues of access to expert knowledge highlight the relationship between conditions of uncertainty, technoscientific expertise and identity. The events of the study highlight the challenges faced by contemporary technoscientific corporations such as chemicals companies as they must deliver on requirements of transparency and openness, while maintaining technoscientific capacity and strong internal identity. We conclude that the study demonstrates the co-existence of social processes of individualization and detraditionalization with quasi-traditions which maintain authority, thus challenging the radical distinctions made in the literature between modernity and late or reflexive modernity. © 2008 Elsevier Ltd. All rights reserved
Organising for Ecological Repair: Reconstructing Land Management Practice
© 2015, © 2015 SAGE Publications. In this article, we explore organising narratives that underpin the generation of effective ecological solutions. We examine the processes of meaning construction in relation to the development of sustainable land management practices in the Landcare organisation in Australia. Meaning construction is situated in a variety of contexts that are themselves strongly influenced by a meta-narrative, which Taylor has labelled the âmodern social imaginaryâ: A shared system of meanings that captures the imaginations of individuals and shapes their social groupings and society. The shift in meaning construction is reflected in the emergence of a narrative of âecological repairâ that involved a process of learning and knowledge development we have labelled protracted sense-making. Our research findings have led us to conclude that the development of successful ecological solutions require an active rewriting of the social imaginary
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