6,533 research outputs found
E-government and the digital divide: A study of English-as-a-Second-Language Users' Information Behaviour
Internet-based technologies are increasingly used by organisations and governments to offer services to consumers and the public in a quick and efficient manner, removing the need for face-to-face conversations and human advisors. Despite their obvious benefits for most users, these online systems may present barriers of access to certain groups in society which may lead to information poverty.
In this study we consider the information behaviour of ten ESL (English as a Second Language) participants as they conduct four search tasks designed to reflect actual information seeking situations. Our results suggest that, despite a perception that they have a good understanding of English, they often choose documents that are only partially or tangentially relevant. There were significant differences in the behaviour of participants given their perceived confidence in using English to perform search tasks. Those who were confident took riskier strategies and were less thorough, leading to them bookmarking a larger proportion of non-relevant documents. The results of this work have potentially profound repercussions for how e-government services are provided and how second-language speakers are assisted in their use of these
CFHT AO Imaging of the CLASS Gravitational Lens System B1359+154
We present adaptive optics imaging of the CLASS gravitational lens system
B1359+154 obtained with the Canada-France-Hawaii Telescope (CFHT) in the
infrared K band. The observations show at least three brightness peaks within
the ring of lensed images, which we identify as emission from multiple lensing
galaxies. The results confirm the suspected compound nature of the lens, as
deduced from preliminary mass modeling. The detection of several additional
nearby galaxies suggests that B1359+154 is lensed by the compact core of a
small galaxy group. We attempted to produce an updated lens model based on the
CFHT observations and new 5-GHz radio data obtained with the MERLIN array, but
there are too few constraints to construct a realistic model at this time. The
uncertainties inherent with modeling compound lenses make B1359+154 a
challenging target for Hubble constant determination through the measurement of
differential time delays. However, time delays will offer additional
constraints to help pin down the mass model. This lens system therefore
presents a unique opportunity to directly measure the mass distribution of a
galaxy group at intermediate redshift.Comment: 12 pages including 3 figures; ApJL accepte
Symmetry of two terminal, non-linear electric conduction
The well-established symmetry relations for linear transport phenomena can
not, in general, be applied in the non-linear regime. Here we propose a set of
symmetry relations with respect to bias voltage and magnetic field for the
non-linear conductance of two-terminal electric conductors. We experimentally
confirm these relations using phase-coherent, semiconductor quantum dots.Comment: 4 pages, 4 figure
Bayesian Probabilities and the Histories Algebra
We attempt a justification of a generalisation of the consistent histories
programme using a notion of probability that is valid for all complete sets of
history propositions. This consists of introducing Cox's axioms of probability
theory and showing that our candidate notion of probability obeys them. We also
give a generalisation of Bayes' theorem and comment upon how Bayesianism should
be useful for the quantum gravity/cosmology programmes.Comment: 10 pages, accepted by Int. J. Theo. Phys. Feb 200
Prevalence and risk factors for mast cell tumours in dogs in England
BACKGROUND: Mast cell tumour (MCT) appears to be a frequent tumour type in dogs, though there is little published in relation to its frequency in dogs in the UK. The current study aimed to investigate prevalence and risk factors for MCTs in dogs attending English primary-care veterinary practices. METHODS: Electronic patient records from practices participating in the VetCompass animal surveillance project between July 2007 and June 2013 were searched for MCT diagnosis. Various search terms and standard diagnostic terms (VeNom codes) identified records containing MCT diagnoses, which were evaluated against clinical criteria for inclusion to the study. MCT prevalence for the entire dataset and specific breed types were calculated. Descriptive statistics characterised MCT cases and multivariable logistic regression methods evaluated risk factors for association with MCT (P < 0.05). RESULTS: Within a population of 168,636 dogs, 453 had MCT, yielding a prevalence of 0.27% (95% confidence interval (CI) 0.24% - 0.29%). The highest breed type specific prevalences were for the Boxer at 1.95% (95% CI 1.40% - 2.51%), Golden Retriever at 1.39% (0.98% - 1.81%) and Weimaraner at 0.85% (95% CI 0.17% to 1.53%). Age, insurance status, neuter status, weight and breed type were associated with MCT diagnosis. Of dogs of specific breed type, the Boxer, Pug and Staffordshire Bull Terrier showed greater odds of MCT diagnosis compared with crossbred dogs. Conversely, the German Shepherd Dog, Border Collie, West Highland White Terrier, Springer Spaniel and Cocker Spaniel had reduced odds of MCT diagnosis compared with crossbred dogs. No association was found between MCT diagnosis and sex. CLINICAL SIGNIFICANCE: This study highlights a clinically significant prevalence of MCT and identifies specific breed types with predisposition to MCT, potentially aiding veterinarian awareness and facilitating diagnosis
Mathematics difficulties in extremely preterm children : evidence of a specific deficit in basic mathematics processing
Background:
Extremely preterm (EP, <26 wk gestation) children have been observed to have poor academic achievement in comparison to their term-born peers, especially in mathematics. This study investigated potential underlying causes of this difficulty.
Methods:
A total of 219 EP participants were compared with 153 term-born control children at 11 y of age. All children were assessed by a psychologist on a battery of standardized cognitive tests and a number estimation test assessing children’s numerical representations.
Results:
EP children underperformed in all tests in comparison with the term controls (the majority of Ps < 0.001). Different underlying relationships between performance on the number estimation test and mathematical achievement were found in EP as compared with control children. That is, even after controlling for cognitive ability, a relationship between number representations and mathematical performance persisted for EP children only (EP: r = 0.346, n = 186, P < 0.001; control: r = 0.095, n = 146, P = 0.256).
Conclusion:
Interventions for EP children may target improving children’s numerical representations in order to subsequently remediate their mathematical skills
Probing the Sensitivity of Electron Wave Interference to Disorder-Induced Scattering in Solid-State Devices
The study of electron motion in semiconductor billiards has elucidated our
understanding of quantum interference and quantum chaos. The central assumption
is that ionized donors generate only minor perturbations to the electron
trajectories, which are determined by scattering from billiard walls. We use
magnetoconductance fluctuations as a probe of the quantum interference and show
that these fluctuations change radically when the scattering landscape is
modified by thermally-induced charge displacement between donor sites. Our
results challenge the accepted understanding of quantum interference effects in
nanostructures.Comment: 8 pages, 5 figures, Submitted to Physical Review
Pion Cloud Contribution to K+ Nucleus Scattering
A careful reanalysis is done of the contribution to nucleus
scattering from the interaction of the kaon with the virtual pion cloud. The
usual approximations made in the evaluation of the related kaon selfenergy are
shown to fail badly. We also find new interaction mechanisms which provide
appreciable corrections to the kaon selfenergy. Some of these contribute to the
imaginary part below pion creation threshold. The inclusion of these new
mechanisms in the inelastic part of the optical potential produces a
significant improvement in the differential and total nuclear cross
sections. Uncertainties remain in the dispersive part of the optical potential.Comment: 27 pages, 17 figures (not all of them included, please request them),
report UG-DFM-2/9
'We did everything we could'- A qualitative study exploring the acceptability of maternal-fetal surgery for spina bifida to parents
OBJECTIVE: To explore the concepts and strategies parents employ when considering maternal-fetal surgery (MFS) as an option for the management of spina bifida (SB) in their fetus, and how this determines the acceptability of the intervention. METHODS: A two-centre interview study enrolling parents whose fetuses with SB were eligible for MFS. To assess differences in acceptability, parents opting for MFS (n=24) were interviewed at three different moments in time: prior to the intervention, directly after the intervention and 3-6 months after birth. Parents opting for termination of pregnancy (n=5) were interviewed only once. Themes were identified and organised in line with the framework of acceptability. RESULTS: To parents opting for MFS, the intervention was perceived as an opportunity that needed to be taken. Feelings of parental responsibility drove them to do anything in their power to improve their future child's situation. Expectations seemed to be realistic yet were driven by hope for the best outcome. None expressed decisional regret at any stage, despite substantial impact and, at times, disappointing outcomes. For the small group of participants, who decided to opt for termination of pregnancy (TOP), MFS was not perceived as an intervention that substantially could improve the quality of their future child's life. CONCLUSION: Prospective parents opting for MFS were driven by their feelings of parental responsibility. They recognise the fetus as their future child and value information and care focusing on optimising the child's future health. In the small group of parents opting for TOP, MFS was felt to offer insufficient certainty of substantial improvement in quality of life and the perceived severe impact of SB drove their decision to end the pregnancy This article is protected by copyright. All rights reserved
Excitonic condensation in a symmetric electron-hole bilayer
Using Diffusion Monte Carlo simulations we have investigated the ground state
of a symmetric electron-hole bilayer and determined its phase diagram at T=0.
We find clear evidence of an excitonic condensate, whose stability however is
affected by in-layer electronic correlation. This stabilizes the electron-hole
plasma at large values of the density or inter-layer distance, and the Wigner
crystal at low density and large distance. We have also estimated pair
correlation functions and low order density matrices, to give a microscopic
characterization of correlations, as well as to try and estimate the condensate
fraction.Comment: 4 pages, 3 figures, 2 table
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