556 research outputs found
The role of the labour bureaux in South Africa: A critique of the Riekert Commission Report
African Studies Seminar series. Paper presented 1980
South Africa's regional political economy: A critical analysis of reform strategy in the 1980s.
African Studies Seminar series. Paper presented October, 1985Since the late 1970s the apartheid state has faced a sustained
and deepening crisis of legitimation.(1) This crisis has been
exacerbated by the attempt, and failure, to implement the post-
Soweto 'Total Strategy' reforms - reforms which, in the case of
the black people of South Africa, left the territorial and
political basis of grand apartheid intact. Since the end of the
short-lived boom of 1979-82, the crisis of political legitimacy
has been amplified by the slide into economic depression, and the
scope for concessionary economic reforms has been drastically
curtailed.
For some time, the state has been caught up with the
immediate threat of escalating opposition in the townships, the
symptoms of the deepening economic crisis and spreading
international hostility to apartheid. But while this has been
happening, elements within the ruling groups, both inside and
outside the state, have for some time been attempting to map out
a longer-term strategic offensive aimed at defusing political
conflict and re-structuring the economy. Faced with a shrinking
material basis for concessionary economic reform and growing
mobilisation behind the demand for the extension of political
rights, the country's ruling groups have begun the search for
political solutions to the crisis.
The schemes now being formulated take as their starting point
the ultimate inevitability of political incorporation of black
people into a single national state in South Africa. They aim to
meet this in ways that ensure that real power remains in the
hands of the ruling classes.
The move towards political reforms for black people has gone
beyond the stage of discussion and planning in certain areas of
policy. Already an important pillar of the emerging strategy has
gained expression in local government measures passed in 1985.
(2) However much of what is planned has so far only appeared in
general policy statements. It is also evident that important
facets of the strategy are still in the stage of formulation or
are deliberately being held back for the moment. The fluidity of
political conditions in South Africa is such that state strategy
is the subject matter of open debate and contestation, and is
unusually susceptible to official reconsideration and
reformulation. Nevertheless we believe it is possible to identify
the major contours of an emerging strategy which has been pursued
with increasing determination by reformers within the commanding
heights of the state since late in 1984.
This offensive is significant in that it goes well beyond the
policy package associated with the Wiehahn and Riekert Commission
reports, the Koornhof Bills, the new constitution, and the
confederation of ethnic states - it goes beyond the 'Total
Strategy' formulated by PW Botha in the late 1970s. (3) In
contrast to these policies, it is based on an abandonment of the
political and territorial premises of apartheid, though not
necessarily of race or ethnicity, and envisages the eventual reincorporation
of the bantustans into a single national South
African state.
The manner in which this will occur is by no means clear or
decided. However, this process of political re-integration of the
bantustans is intended ultimately to result in the reorganisation
of the territorial basis of South Africa's economic
and political system. Central to the reform strategy is the
conception that the present provinces and bantustans will be
superceded by metropolitan and regionally-based administrative
structures through a process of merging, absorption and crosscutting
of present geographical boundaries. It is this geographic
outcome of the intended reform strategy that has led us to
describe the complex of evolving measures as the state's regional
strategy.
The aim of this article is to describe, anticipate and
critically analyse the outlines of the emerging regional
strategy. Its three major components are new controls on labour
movement and settlement, regional development policies (notably
industrial decentralisation), and local and second tier
government reforms and corresponding constitutional changes. We
examine each of these three components and their
interconnections. A central issue taken up in the paper is the debate over the
possible construction of a federal system in South Africa. We
examine major alternative conceptions of the basis of federalism
- geographic and ethnic - and show how they correspond to or
contradict other plans to divide South Africa into metropolitan
and wider planning and administrative regions.
The paper ends with an assessment and critical analysis of
the regional strategy
Murchison Widefield Array and XMM-Newton observations of the Galactic supernova remnant G5.9+3.1
In this paper we discuss the radio continuum and X-ray properties of the
so-far poorly studied Galactic supernova remnant (SNR) G5.9+3.1. We present the
radio spectral energy distribution (SED) of the Galactic SNR G5.9+3.1 obtained
with the Murchison Widefield Array (MWA). Combining these new observations with
the surveys at other radio continuum frequencies, we discuss the integrated
radio continuum spectrum of this particular remnant. We have also analyzed an
archival XMM-Newton observation, which represents the first detection of X-ray
emission from this remnant. The SNR SED is very well explained by a simple
power-law relation. The synchrotron radio spectral index of G5.9+3.1, is
estimated to be 0.420.03 and the integrated flux density at 1GHz to be
around 2.7Jy. Furthermore, we propose that the identified point radio source,
located centrally inside the SNR shell, is most probably a compact remnant of
the supernova explosion. The shell-like X-ray morphology of G5.9+3.1 as
revealed by XMM-Newton broadly matches the spatial distribution of the radio
emission, where the radio-bright eastern and western rims are also readily
detected in the X-ray while the radio-weak northern and southern rims are weak
or absent in the X-ray. Extracted MOS1+MOS2+PN spectra from the whole SNR as
well as the north, east, and west rims of the SNR are fit successfully with an
optically thin thermal plasma model in collisional ionization equilibrium with
a column density N_H~0.80x cm and fitted temperatures spanning
the range kT~0.14-0.23keV for all of the regions. The derived electron number
densities n_e for the whole SNR and the rims are also roughly comparable
(ranging from ~ cm to ~ cm, where f
is the volume filling factor). We also estimate the swept-up mass of the X-ray
emitting plasma associated with G5.9+3.1 to be ~.Comment: Accepted for publication in A&
WSClean : an implementation of a fast, generic wide-field imager for radio astronomy
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. © 2014 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.Astronomical widefield imaging of interferometric radio data is computationally expensive, especially for the large data volumes created by modern non-coplanar many-element arrays. We present a new widefield interferometric imager that uses the w-stacking algorithm and can make use of the w-snapshot algorithm. The performance dependencies of CASA's w-projection and our new imager are analysed and analytical functions are derived that describe the required computing cost for both imagers. On data from the Murchison Widefield Array, we find our new method to be an order of magnitude faster than w-projection, as well as being capable of full-sky imaging at full resolution and with correct polarisation correction. We predict the computing costs for several other arrays and estimate that our imager is a factor of 2-12 faster, depending on the array configuration. We estimate the computing cost for imaging the low-frequency Square-Kilometre Array observations to be 60 PetaFLOPS with current techniques. We find that combining w-stacking with the w-snapshot algorithm does not significantly improve computing requirements over pure w-stacking. The source code of our new imager is publicly released.Peer reviewedFinal Published versio
Membership of English sport clubs: A dynamic panel data analysis of the trickle-down effect
Investments in elite sport and major sporting events are often justified in sport policy by various rationales, one of which is a âtrickle-downâ effect whereby successful athletes have a positive impact on general sport participation rates. This effect is likely to be greater when hosting events, as home advantage can contribute to sporting success. The purpose of this research is to explore the possibility of a trickle-down effect on sports club membership in the United Kingdom in the context of the 2012 London Olympic Games. Secondary data were collected on sports club membership levels in 33 sports, over a ten-year period, from 2007â2016 (n = 330). Sporting success was measured by the number of gold medals won in international competitions, the number of major sport events hosted in the UK, and the results of the BBCâs Sports Personality of the Year award (SPOTY). The outcomes of a dynamic panel regression analysis show a causal relationship between the trickle-down effect and sports club membership over a four-year period
Calibration and Stokes Imaging with Full Embedded Element Primary Beam Model for the Murchison Widefield Array
15 pages, 11 figures. Accepted for publication in PASA. © Astronomical Society of Australia 2017The Murchison Widefield Array (MWA), located in Western Australia, is one of the low-frequency precursors of the international Square Kilometre Array (SKA) project. In addition to pursuing its own ambitious science program, it is also a testbed for wide range of future SKA activities ranging from hardware, software to data analysis. The key science programs for the MWA and SKA require very high dynamic ranges, which challenges calibration and imaging systems. Correct calibration of the instrument and accurate measurements of source flux densities and polarisations require precise characterisation of the telescope's primary beam. Recent results from the MWA GaLactic Extragalactic All-sky MWA (GLEAM) survey show that the previously implemented Average Embedded Element (AEE) model still leaves residual polarisations errors of up to 10-20 % in Stokes Q. We present a new simulation-based Full Embedded Element (FEE) model which is the most rigorous realisation yet of the MWA's primary beam model. It enables efficient calculation of the MWA beam response in arbitrary directions without necessity of spatial interpolation. In the new model, every dipole in the MWA tile (4 x 4 bow-tie dipoles) is simulated separately, taking into account all mutual coupling, ground screen and soil effects, and therefore accounts for the different properties of the individual dipoles within a tile. We have applied the FEE beam model to GLEAM observations at 200 - 231 MHz and used false Stokes parameter leakage as a metric to compare the models. We have determined that the FEE model reduced the magnitude and declination-dependent behaviour of false polarisation in Stokes Q and V while retaining low levels of false polarisation in Stokes U.Peer reviewedFinal Accepted Versio
The Spectral Energy Distribution of Powerful Starburst Galaxies I : Modelling the Radio Continuum
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. © 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.We have acquired radio-continuum data between 70MHz and 48 GHz for a sample of 19 southern starburst galaxies at moderate redshifts (0.067 < z < 0.227) with the aim of separating synchrotron and free-free emission components. Using a Bayesian framework, we find the radio continuum is rarely characterized well by a single power law, instead often exhibiting lowfrequency turnovers below 500 MHz, steepening at mid to high frequencies, and a flattening at high frequencies where free-free emission begins to dominate over the synchrotron emission. These higher order curvature components may be attributed to free-free absorption across multiple regions of star formation with varying optical depths. The decomposed synchrotron and free-free emission components in our sample of galaxies form strong correlations with the total-infrared bolometric luminosities. Finally, we find that without accounting for free-free absorption with turnovers between 90 and 500MHz the radio continuum at low frequency (v < 200 MHz) could be overestimated by upwards of a factor of 12 if a simple power-law extrapolation is used from higher frequencies. The mean synchrotron spectral index of our sample is constrained to be α = -1.06, which is steeper than the canonical value of -0.8 for normal galaxies. We suggest this may be caused by an intrinsically steeper cosmic ray distribution.Peer reviewe
The Spectral Energy Distribution of Powerful Starburst Galaxies I: Modelling the Radio Continuum
We have acquired radio continuum data between 70\,MHz and 48\,GHz for a
sample of 19 southern starburst galaxies at moderate redshifts () with the aim of separating synchrotron and free-free emission
components. Using a Bayesian framework we find the radio continuum is rarely
characterised well by a single power law, instead often exhibiting low
frequency turnovers below 500\,MHz, steepening at mid-to-high frequencies, and
a flattening at high frequencies where free-free emission begins to dominate
over the synchrotron emission. These higher order curvature components may be
attributed to free-free absorption across multiple regions of star formation
with varying optical depths. The decomposed synchrotron and free-free emission
components in our sample of galaxies form strong correlations with the
total-infrared bolometric luminosities. Finally, we find that without
accounting for free-free absorption with turnovers between 90 to 500\,MHz the
radio-continuum at low frequency (\,MHz) could be overestimated by
upwards of a factor of twelve if a simple power law extrapolation is used from
higher frequencies. The mean synchrotron spectral index of our sample is
constrained to be , which is steeper then the canonical value of
for normal galaxies. We suggest this may be caused by an intrinsically
steeper cosmic ray distribution
DNA replication stress restricts ribosomal DNA copy number
Ribosomal RNAs (rRNAs) in budding yeast are encoded by ~100â200 repeats of a 9.1kb sequence arranged in tandem on chromosome XII, the ribosomal DNA (rDNA) locus. Copy number of rDNA repeat units in eukaryotic cells is maintained far in excess of the requirement for ribosome biogenesis. Despite the importance of the repeats for both ribosomal and non-ribosomal functions, it is currently not known how ânormalâ copy number is determined or maintained. To identify essential genes involved in the maintenance of rDNA copy number, we developed a droplet digital PCR based assay to measure rDNA copy number in yeast and used it to screen a yeast conditional temperature-sensitive mutant collection of essential genes. Our screen revealed that low rDNA copy number is associated with compromised DNA replication. Further, subculturing yeast under two separate conditions of DNA replication stress selected for a contraction of the rDNA array independent of the replication fork blocking protein, Fob1. Interestingly, cells with a contracted array grew better than their counterparts with normal copy number under conditions of DNA replication stress. Our data indicate that DNA replication stresses select for a smaller rDNA array. We speculate that this liberates scarce replication factors for use by the rest of the genome, which in turn helps cells complete DNA replication and continue to propagate. Interestingly, tumors from mini chromosome maintenance 2 (MCM2)-deficient mice also show a loss of rDNA repeats. Our data suggest that a reduction in rDNA copy number may indicate a history of DNA replication stress, and that rDNA array size could serve as a diagnostic marker for replication stress. Taken together, these data begin to suggest the selective pressures that combine to yield a ânormalâ rDNA copy number
High-energy sources at low radio frequency : the Murchison Widefield Array view of Fermi blazars
This is the accepted version of the following article: Giroletti, M. et al., A&A, 588 (2016) A141, which has been published in final form at DOI: http://dx.doi.org/10.1051/0004-6361/201527817. This article may be used for non-commercial purposes in accordance with the EDP Sciences self-archiving policies.Low-frequency radio arrays are opening a new window for the study of the sky, both to study new phenomena and to better characterize known source classes. Being flat-spectrum sources, blazars are so far poorly studied at low radio frequencies. We characterize the spectral properties of the blazar population at low radio frequency compare the radio and high-energy properties of the gamma-ray blazar population, and search for radio counterparts of unidentified gamma-ray sources. We cross-correlated the 6,100 deg^2 Murchison Widefield Array Commissioning Survey catalogue with the Roma blazar catalogue, the third catalogue of active galactic nuclei detected by Fermi-LAT, and the unidentified members of the entire third catalogue of gamma-ray sources detected by \fermilat. When available, we also added high-frequency radio data from the Australia Telescope 20 GHz catalogue. We find low-frequency counterparts for 186 out of 517 (36%) blazars, 79 out of 174 (45%) gamma-ray blazars, and 8 out of 73 (11%) gamma-ray blazar candidates. The mean low-frequency (120--180 MHz) blazar spectral index is : blazar spectra are flatter than the rest of the population of low-frequency sources, but are steeper than at GHz frequencies. Low-frequency radio flux density and gamma-ray energy flux display a mildly significant and broadly scattered correlation. Ten unidentified gamma-ray sources have a (probably fortuitous) positional match with low radio frequency sources. Low-frequency radio astronomy provides important information about sources with a flat radio spectrum and high energy. However, the relatively low sensitivity of the present surveys still misses a significant fraction of these objects. Upcoming deeper surveys, such as the GaLactic and Extragalactic All-Sky MWA (GLEAM) survey, will provide further insight into this population.Peer reviewedFinal Published versio
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