203 research outputs found
Radio Observations of the Hubble Deep Field South Region III: The 2.5, 5.2 and 8.7 GHz Catalogues and Radio Source Properties
Deep radio observations of a wide region centred on the Hubble Deep Field
South have been performed, providing one of the most sensitive set of radio
observations acquired on the Australia Telescope Compact Array to date. A
central rms of ~10 microJy is reached at four frequencies (1.4, 2.5, 5.2 and
8.7 GHz). In this paper the full source catalogues from the 2.5, 5.2 and 8.7
GHz observations are presented to complement Paper II, along with a detailed
analysis of image quality and noise. We produce a consolidated catalogue by
matching sources across all four frequencies of our survey. Radio spectral
indices are used to investigate the nature of the radio sources and identify a
number of sources with flat or inverted radio spectra, which indicates AGN
activity. We also find several other interesting sources, including a broadline
emitting radio galaxy, a giant radio galaxy and three Gigahertz Peaked Spectrum
sources.Comment: Accepted by AJ. 13 figures and 13 table
The landscape of gifted and talented education in England and Wales: How are teachers implementing policy?
This is an Author's Accepted Manuscript of an article published in Research Papers in Education, 27(2), 167-186, 2012, copyright Taylor & Francis, available online at: http://www.tandfonline.com/10.1080/02671522.2010.509514.This paper explores the evidence relating to how primary schools are responding to the ‘gifted and talented’ initiative in England and Wales. A questionnaire survey which invited both closed and open-ended responses was carried out with a national sample of primary schools. The survey indicated an increasing proportion of coordinators, compared with a survey carried out in 1996, were identifying their gifted and talented children as well as having associated school policies. However, the survey also highlighted a number of issues which need addressing if the initiative is to achieve its objective of providing the best possible educational opportunities for children. For example, it was found that a significant number of practitioners were not aware of the existence of the National Quality Standards for gifted and talented education, provided by the UK government in 2007, and the subject-specific criteria provided by the UK’s Curriculum Authority for identification and provision have been largely ignored. The process of identifying children to be placed on the ‘gifted and talented’ register seems haphazard and based on pragmatic reasons. Analysis of teachers’ responses also revealed a range of views and theoretical positioning held by them, which have implications for classroom practice. As the ‘gifted and talented’ initiative in the UK is entering a second decade, and yet more significant changes in policy are introduced, pertinent questions need to be raised and given consideration
People with advanced cancer: the process of living well with awareness of dying
Literature suggests that it is possible to live well with advanced cancer but little is known about the process. In this article, we present a secondary analysis of experiences of living with advanced cancer (n = 22) that refines the theory of “Living Well with Chronic Illness” for a different context and population. The refined theory explains the experience of living well with advanced cancer illuminating a five-phase iterative process: struggling, accepting, living with advanced cancer, sharing the illness experience, and reconstructing life. These five phases revolve around the core concept of Awareness of Dying, which varied from awareness of the possibility of dying, to accepting the possibility of dying, to acceptance that “I am dying.” Awareness of Dying led to a focus on living well with advanced cancer and movement towards living a life rather than living an illness
Radio Observations of the Hubble Deep Field South Region II: The 1.4 GHz Catalogue and Source Counts
This paper is part of a series describing the results from the Australia
Telescope Hubble Deep Field South (ATHDFS) survey obtained with the Australia
Telescope Compact Array (ATCA). This survey consists of observations at 1.4,
2.5, 5.2 and 8.7 GHz, all centred on the Hubble Deep Field South.
Here we present the first results from the extended observing campaign at 1.4
GHz. A total of 466 sources have been catalogued to a local sensitivity of 5
sigma (11 microJy rms). A source extraction technique is developed which: 1)
successfully excludes spurious sources from the final source catalogues, and 2)
accounts for the non-uniform noise in our image. A source catalogue is
presented and the general properties of the 1.4 GHz image are discussed. We
also present source counts derived from our ATHDFS 1.4 GHz catalogue.
Particular attention is made to ensure the counts are corrected for survey
incompleteness and systematic effects. Our counts are consistent with other
surveys (e.g. ATESP, VIRMOS, and Phoenix Deep Field), and we find, in common
with these surveys, that the HDFN counts are systematically lower.Comment: Accepted by AJ. 51 pages, 21 figures, 2 table
Structures of the CCR5 N Terminus and of a Tyrosine-Sulfated Antibody with HIV-1 gp120 and CD4
The CCR5 co-receptor binds to the HIV-l gp120 envelope glycoprotein and facilitates HIV-l entry into cells. Its N terminus is tyrosine-sulfated, as are many antibodies that react with the co-receptor binding site on gp120. We applied nuclear magnetic resonance and crystallographic techniques to analyze the structure of the CCR5 N terminus and that of the tyrosine-sulfated antibody 412d in complex with gp120 and CD4. The conformations of tyrosine-sulfated regions of CCR5 (α-helix) and 412d (extendedloop) are surprisingly different. Nonetheless, a critical sulfotyrosine on CCR5 and on 412d induces similar structural rearrangements in gp120. These results now provide a framework for understanding HIV-l interactions with the CCR5 N terminus during viral entry and define a conserved site on gp120, whose recognition of sulfotyrosine engenders posttranslational mimicry by the immune system
Improving health care quality for racial/ethnic minorities: a systematic review of the best evidence regarding provider and organization interventions
BACKGROUND: Despite awareness of inequities in health care quality, little is known about strategies that could improve the quality of healthcare for ethnic minority populations. We conducted a systematic literature review and analysis to synthesize the findings of controlled studies evaluating interventions targeted at health care providers to improve health care quality or reduce disparities in care for racial/ethnic minorities. METHODS: We performed electronic and hand searches from 1980 through June 2003 to identify randomized controlled trials or concurrent controlled trials. Reviewers abstracted data from studies to determine study characteristics, results, and quality. We graded the strength of the evidence as excellent, good, fair or poor using predetermined criteria. The main outcome measures were evidence of effectiveness and cost of strategies to improve health care quality or reduce disparities in care for racial/ethnic minorities. RESULTS: Twenty-seven studies met criteria for review. Almost all (n = 26) took place in the primary care setting, and most (n = 19) focused on improving provision of preventive services. Only two studies were designed specifically to meet the needs of racial/ethnic minority patients. All 10 studies that used a provider reminder system for provision of standardized services (mostly preventive) reported favorable outcomes. The following quality improvement strategies demonstrated favorable results but were used in a small number of studies: bypassing the physician to offer preventive services directly to patients (2 of 2 studies favorable), provider education alone (2 of 2 studies favorable), use of a structured questionnaire to assess adolescent health behaviors (1 of 1 study favorable), and use of remote simultaneous translation (1 of 1 study favorable). Interventions employing more than one main strategy were used in 9 studies with inconsistent results. There were limited data on the costs of these strategies, as only one study reported cost data. CONCLUSION: There are several promising strategies that may improve health care quality for racial/ethnic minorities, but a lack of studies specifically targeting disease areas and processes of care for which disparities have been previously documented. Further research and funding is needed to evaluate strategies designed to reduce disparities in health care quality for racial/ethnic minorities
Structures of the CCR5 N Terminus and of a Tyrosine-Sulfated Antibody with HIV-1 gp120 and CD4
The CCR5 co-receptor binds to the HIV-l gp120 envelope glycoprotein and facilitates HIV-l entry into cells. Its N terminus is tyrosine-sulfated, as are many antibodies that react with the co-receptor binding site on gp120. We applied nuclear magnetic resonance and crystallographic techniques to analyze the structure of the CCR5 N terminus and that of the tyrosine-sulfated antibody 412d in complex with gp120 and CD4. The conformations of tyrosine-sulfated regions of CCR5 (α-helix) and 412d (extendedloop) are surprisingly different. Nonetheless, a critical sulfotyrosine on CCR5 and on 412d induces similar structural rearrangements in gp120. These results now provide a framework for understanding HIV-l interactions with the CCR5 N terminus during viral entry and define a conserved site on gp120, whose recognition of sulfotyrosine engenders posttranslational mimicry by the immune system
Radio Observations of the Hubble Deep Field South Region IV: Optical Properties of the Faint Radio Population
The Australia Telescope Hubble Deep Field-South (ATHDFS) survey of the Hubble
Deep Field South reaches sensitivities of ~10 miceoJyJy at 1.4, 2.5, 5.2 and
8.7 GHz, making the ATHDFS one of the deepest surveys ever performed with the
Australia Telescope Compact Array. Here we present the optical identifications
of the ATHDFS radio sources using data from the literature. We find that ~66%
of the radio sources have optical counterparts to I = 23.5 mag. Deep HST
imaging of the area identifies a further 12% of radio sources. We present new
spectroscopic observations for 98 of the radio sources, and supplement these
spectroscopic redshifts with photometric ones calculated from 5-band optical
imaging. The host galaxy colors and radio-to-optical ratios indicate that low
luminosity (or "radio quiet") AGN make up a significant proportion of the
sub-mJy radio population, a result which is in accordance with a number of
other deep radio studies. The radio-to-optical ratios of the bright (S_1.4GHz >
1 mJy) sources is consistent with a bimodal distribution.Comment: accepted for publication in A
A panchromatic study of BLAST counterparts: total star-formation rate, morphology, AGN fraction and stellar mass
We carry out a multi-wavelength study of individual galaxies detected by the
Balloon-borne Large Aperture Submillimeter Telescope (BLAST) and identified at
other wavelengths, using data spanning the radio to the ultraviolet (UV). We
develop a Monte Carlo method to account for flux boosting, source blending, and
correlations among bands, which we use to derive deboosted far-infrared (FIR)
luminosities for our sample. We estimate total star-formation rates for BLAST
counterparts with z < 0.9 by combining their FIR and UV luminosities. Star
formation is heavily obscured at L_FIR > 10^11 L_sun, z > 0.5, but the
contribution from unobscured starlight cannot be neglected at L_FIR < 10^11
L_sun, z < 0.25. We assess that about 20% of the galaxies in our sample show
indication of a type-1 active galactic nucleus (AGN), but their submillimeter
emission is mainly due to star formation in the host galaxy. We compute stellar
masses for a subset of 92 BLAST counterparts; these are relatively massive
objects, with a median mass of ~10^11 M_sun, which seem to link the 24um and
SCUBA populations, in terms of both stellar mass and star-formation activity.
The bulk of the BLAST counterparts at z<1 appear to be run-of-the-mill
star-forming galaxies, typically spiral in shape, with intermediate stellar
masses and practically constant specific star-formation rates. On the other
hand, the high-z tail of the BLAST counterparts significantly overlaps with the
SCUBA population, in terms of both star-formation rates and stellar masses,
with observed trends of specific star-formation rate that support strong
evolution and downsizing.Comment: Accepted for publication in the Astrophysical Journal. 44 pages, 11
figures. The SED template for the derivation of L_FIR has changed (added new
figure) and the discussion on the stellar masses has been improved. The
complete set of full-color postage-stamps can be found at
http://blastexperiment.info/results_images/moncelsi
Multi-epoch Spectroscopy of IY UMa: Quiescence, Rise, Normal Outburst & Superoutburst
We exploit rare observations covering the time before and during a normal
outburst in the deeply-eclipsing SU UMa system IY UMa to study the dramatic
changes in the accretion flow and emission at the onset of outburst. Through
Doppler tomography we study the emission distribution, revealing classic
accretion flow behaviour in quiescence, with the stream-disc impact ionizing
the nearby accretion disc. We observe a delay of hours to a couple of days
between the rise in continuum and the rise in the emission lines at the onset
of the outburst. From line profiles and Doppler maps during normal and
superoutburst we conclude that reprocessing of boundary layer radiation is the
dominant emission line mechanism in outburst, and that the normal outburst
began in the outer disc. The stream-disc impact feature (the `orbital hump') in
the H alpha line flux light curve disappears before the onset of the normal
outburst, and may be an observable signal heralding an impending outburst.Comment: 14 pages, 12 figures. Accepted for publication in Monthly Notices of
the Royal Astronomical Societ
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