2,444 research outputs found
Topology of the Galaxy Distribution in the Hubble Deep Fields
We have studied topology of the distribution of the high redshift galaxies
identified in the Hubble Deep Field (HDF) North and South. The two-dimensional
genus is measured from the projected distributions of the HDF galaxies at
angular scales from to . We have also divided the samples into
three redshift slices with roughly equal number of galaxies using photometric
redshifts to see possible evolutionary effects on the topology.
The genus curve of the HDF North clearly indicates clustering of galaxies
over the Poisson distribution while the clustering is somewhat weaker in the
HDF South. This clustering is mainly due to the nearer galaxies in the samples.
We have also found that the genus curve of galaxies in the HDF is consistent
with the Gaussian random phase distribution with no significant redshift
dependence.Comment: 14 pages, 4 figures, submitted to Ap
Creative Business in Australia Learnings from the Creative Industries Innovation Centre, 2009 To 2015
As the largest ever Australian government investment in creative industries development, the Creative Industries Innovation Centre delivered tailored business services to more than 1500 creative businesses from 2009 to 2015 and provided industry intelligence and advice for public policy and peak sectoral activity. This collection gives an overview of the current ‘state of business’ in Australia’s creative industries – both as an industry sector in its own right and as an enabling sector and skills set for other industries – and reflects on business needs, creative industries policy and support services for the sector. With contributions from the Centre’s team of senior business advisers and from leading Australian researchers who worked closely with the Centre –including experts on design-led innovation and the creative economy – and case studies of leading Australia creative businesses, the book is intended as and industry-relevant contribution to business development and public policy
Human schistosomiasis
Human schistosomiasis-or bilharzia-is a parasitic disease caused by trematode fl ukes of the genus Schistosoma. By conservative estimates, at least 230 million people worldwide are infected with Schistosoma spp. Adult schistosome worms colonise human blood vessels for years, successfully evading the immune system while excreting hundreds to thousands of eggs daily, which must either leave the body in excreta or become trapped in nearby tissues. Trapped eggs induce a distinct immune-mediated granulomatous response that causes local and systemic pathological eff ects ranging from anaemia, growth stunting, impaired cognition, and decreased physical fi tness, to organ-specifi c eff ects such as severe hepatosplenism, periportal fi brosis with portal hypertension, and urogenital infl ammation and scarring. At present, preventive public health measures in endemic regions consist of treatment once every 1 or 2 years with the isoquinolinone drug, praziquantel, to suppress morbidity. In some locations, elimination of transmission is now the goal; however, more sensitive diagnostics are needed in both the fi eld and clinics, and integrated environmental and health-care management will be needed to ensure elimination. © Chataway et al. Open Access article distributed under the terms of CC BY
Formality and informality in the summative assessment of motor vehicle apprentices: a case study
This article explores the interaction of formal and informal attributes of competence‐based assessment. Specifically, it presents evidence from a small qualitative case study of summative assessment practices for competence‐based qualifications within apprenticeships in the motor industry in England. The data are analysed through applying an adaptation of a framework for exploring the interplay of formality and informality in learning. This analysis reveals informal mentoring as a significant element which influences not only the process of assessment, but also its outcomes. We offer different possible interpretations of the data and their analysis, and conclude that, whichever interpretation is adopted, there appears to be a need for greater capacity‐building for assessors at a local level. This could acknowledge a more holistic role for assessors; recognise the importance of assessors’ informal practices in the formal retention and achievement of apprentices; and enhance awareness of inequalities that may be reinforced by both informal and formal attributes of assessment practices
Collaboration and contestation in further and higher education partnerships in England: a Bourdieusian field analysis
Internationally, ‘College for All’ policies are creating new forms of vocational higher education (HE), and shifting relationships between HE and further education (FE) institutions. In this paper, we consider the way in which this is being implemented in England, drawing on a detailed qualitative case study of a regional HE–FE partnership to widen participation. We focus on the complex mix of collaboration and contestation that arose within it, and how these affected socially differentiated groups of students following high- and low-status routes through its provision. We outline Bourdieu’s concept of ‘field’ as a framework for our analysis and interpretation, including its theoretical ambiguities regarding the definition and scale of fields. Through hermeneutic dialogue between data and theory, we tentatively suggest that such partnerships represent bridges between HE and FE. These bridges are strong between higher-status institutions, but highly contested between lower-status institutions competing closely for distinction. We conclude that the trajectories and outcomes for socially disadvantaged students require attention and collective action to address the inequalities they face, and that our theoretical approach may have wider international relevance beyond the English case
Challenges to enabling and implementing Natural Flood Management in Scotland
The research for this paper was supported by the Scottish Government RESAS Strategic Research Programme 2011–2016.We explore factors that constrain implementation of Natural Flood Management (NFM), based on qualitative analysis of interviews with those influencing and enabling flood risk management in Scotland. NFM entails collaboration by multiple individuals and organisations to plan and deliver measures such as re-meandering or buffer strips. Our interviewees identified many interacting issues. They particularly focused on difficulties in securing resources, and evidence gaps and uncertainties associated with NFM. Co-ordination was not simple, often requiring new types of skill, expertise, and resources. NFM is thus outside the ‘comfort zone’ of many leading or engaged with flood risk management. These experiences echo and elaborate on other studies of attempts to encourage sustainable flood management. To tackle these challenges, practitioners should reflect how pre-existing ideas and practices may shape and constrain new approaches to managing floods, while research is needed on specific strategies that can assist in enabling change.Publisher PDFPeer reviewe
Interpreting ambiguous ‘trace’ results in Schistosoma mansoni CCA Tests: Estimating sensitivity and specificity of ambiguous results with no gold standard
Background The development of new diagnostics is an important tool in the fight against disease. Latent Class Analysis (LCA) is used to estimate the sensitivity and specificity of tests in the absence of a gold standard. The main field diagnostic for Schistosoma mansoni infection, Kato-Katz (KK), is not very sensitive at low infection intensities. A point-of-care circulating cathodic antigen (CCA) test has been shown to be more sensitive than KK. However, CCA can return an ambiguous ‘trace’ result between ‘positive’ and ‘negative’, and much debate has focused on interpretation of traces results. Methodology/Principle findings We show how LCA can be extended to include ambiguous trace results and analyse S. mansoni studies from both Côte d’Ivoire (CdI) and Uganda. We compare the diagnostic performance of KK and CCA and the observed results by each test to the estimated infection prevalence in the population. Prevalence by KK was higher in CdI (13.4%) than in Uganda (6.1%), but prevalence by CCA was similar between countries, both when trace was assumed to be negative (CCAtn: 11.7% in CdI and 9.7% in Uganda) and positive (CCAtp: 20.1% in CdI and 22.5% in Uganda). The estimated sensitivity of CCA was more consistent between countries than the estimated sensitivity of KK, and estimated infection prevalence did not significantly differ between CdI (20.5%) and Uganda (19.1%). The prevalence by CCA with trace as positive did not differ significantly from estimates of infection prevalence in either country, whereas both KK and CCA with trace as negative significantly underestimated infection prevalence in both countries. Conclusions Incorporation of ambiguous results into an LCA enables the effect of different treatment thresholds to be directly assessed and is applicable in many fields. Our results showed that CCA with trace as positive most accurately estimated infection prevalence
Streaming Algorithm for Euler Characteristic Curves of Multidimensional Images
We present an efficient algorithm to compute Euler characteristic curves of
gray scale images of arbitrary dimension. In various applications the Euler
characteristic curve is used as a descriptor of an image.
Our algorithm is the first streaming algorithm for Euler characteristic
curves. The usage of streaming removes the necessity to store the entire image
in RAM. Experiments show that our implementation handles terabyte scale images
on commodity hardware. Due to lock-free parallelism, it scales well with the
number of processor cores. Our software---CHUNKYEuler---is available as open
source on Bitbucket.
Additionally, we put the concept of the Euler characteristic curve in the
wider context of computational topology. In particular, we explain the
connection with persistence diagrams
High-Resolution Continuum Imaging at 1.3 and 0.7 cm of the W3 IRS 5 Region
High-resolution images of the hypercompact HII regions (HCHII) in W3 IRS 5
taken with the Very Large Array (VLA) at 1.3 and 0.7 cm are presented. Four
HCHII regions were detected with sufficient signal-to-noise ratios to allow the
determination of relevant parameters such as source position, size and flux
density. The sources are slightly extended in our ~0.2 arcsecond beams; the
deconvolved radii are less than 240 AU. A comparison of our data with VLA
images taken at epoch 1989.1 shows proper motions for sources IRS 5a and IRS
5f. Between 1989.1 and 2002.5, we find a proper motion of 210 mas at a position
angle of 12 deg for IRS 5f and a proper motion of 190 mas at a position angle
of 50 deg for IRS 5a. At the assumed distance to W3 IRS 5, 1.83 +/- 0.14 kpc,
these offsets translate to proper motions of ~135 km/s and ~122 km/s$
respectively. These sources are either shock ionized gas in an outflow or
ionized gas ejected from high mass stars. We find no change in the positions of
IRS 5d1/d2 and IRS 5b; and we show through a comparison with archival NICMOS
2.2 micron images that these two radio sources coincide with the infrared
double constituting W3 IRS 5. These sources contain B or perhaps O stars. The
flux densities of the four sources have changed compared to the epoch 1989.1
results. In our epoch 2002.5 data, none of the spectral indicies obtained from
flux densities at 1.3 and 0.7 cm are consistent with optically thin free-free
emission; IRS 5d1/d2 shows the largest increase in flux density from 1.3 cm to
0.7 cm. This may be an indication of free-free optical depth within an ionized
wind, a photoevaporating disk, or an accretion flow. It is less likely that
this increase is caused by dust emission at 0.7 cm.Comment: 13 pages, 3 figures To be published in The Astrophysical Journa
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