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

Human and fishing vessel losses in sea accidents in the UK fishing industry from 1948 to 2008

Objective. To investigate long-term trends in mortality rates for accidents to fishing vessels in the UK fishing industry from 1948 to 2008; to investigate the circumstances and causes of these fishing vessel accidents and trends in fishing vessel losses. Material and methods. Examination of paper death inquiry files, death registers, marine accident investigative files, annual casualty and death returns. Results. Of 1039 fatalities from accidents to UK fishing vessels from 1948 to 2008, most (65%) resulted from vessels that foundered (or capsized or disappeared), followed by vessels grounding (21%), collisions (7%), and fires and explosions (5%). There was a significant increase over time of 1.04% per year in the overall fishing vessel loss rate and for vessels that foundered (5.19%), a reduction for vessels grounding (1.13%), but no trends for collisions or fires and explosions. Regarding mortality, there was a significant reduction over time for grounding (1.44%) and a non-significant reduction for vessel accidents overall, but no trends for other types of vessel accident. Mortality was highest during the winter months (for foundering and grounding), during night time (for grounding, fires and explosions), and afternoons (foundering and collisions). Since 1976, most fatalities from collisions (83%) occurred in the English Channel and North Sea, while 49% from grounding occurred off the west coast of Scotland. Conclusion. The mortality rate from fishing vessel casualties in UK fishing is still very high. Fatalities in recent years have often been linked to fishing vessels that are unstable, overloaded, and unseaworthy

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

Algorithmic Debugging of Real-World Haskell Programs: Deriving Dependencies from the Cost Centre Stack

Existing algorithmic debuggers for Haskell require a transformation of all modules in a program, even libraries that the user does not want to debug and which may use language features not supported by the debugger. This is a pity, because a promising ap- proach to debugging is therefore not applicable to many real-world programs. We use the cost centre stack from the Glasgow Haskell Compiler profiling environment together with runtime value observations as provided by the Haskell Object Observation Debugger (HOOD) to collect enough information for algorithmic debugging. Program annotations are in suspected modules only. With this technique algorithmic debugging is applicable to a much larger set of Haskell programs. This demonstrates that for functional languages in general a simple stack trace extension is useful to support tasks such as profiling and debugging

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

Myelination of Preterm Brain Networks at Adolescence

Prematurity and preterm stressors severely affect the development of infants born before 37 weeks of gestation, with increasing effects seen at earlier gestations. Although preterm mortality rates have declined due to the advances in neonatal care, disability rates, especially in middle-income settings, continue to grow. With the advances in MRI imaging technology, there has been a focus on safely imaging the preterm brain to better understand its development and discover the brain regions and networks affected by prematurity. Such studies aim to support interventions and improve the neurodevelopment of preterm infants and deliver accurate prognoses. Few studies, however, have focused on the fully developed brain of preterm born infants, especially in extremely preterm subjects. To assess the long-term effect of prematurity on the adult brain, myelin related biomarkers such as myelin water fraction and g-ratio are measured for a cohort of 19-year-old extremely preterm subjects. Using multi-modal imaging techniques that combine T2 relaxometry and neurite density information, the results show that specific regions of the brain associated with white matter injuries due to preterm birth, such as the Posterior Limb of the Internal Capsule and Corpus Callosum, are still less myelinated in adulthood. Such findings might imply reduced connectivity in the adult preterm brain and explain the poor cognitive outcome

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

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

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

The effect of cell-to-cell variations and thermal gradients on the performance and degradation of lithium-ion battery packs

The performance of lithium-ion battery packs are often extrapolated from single cell performance however uneven currents in parallel strings due to cell-to-cell variations, thermal gradients and/or cell interconnects can reduce the overall performance of a large scale lithium-ion battery pack. In this work, we investigate the performance implications caused by these factors by simulating six parallel connected batteries based on a thermally coupled single particle model with the solid electrolyte interphase growth degradation mechanism modelled. Experimentally validated simulations show that cells closest to the load points of a pack experience higher currents than cells further away due to uneven overpotentials caused by the interconnects. When a cell with a four times greater internal impedance was placed in the location with the higher currents this actually helped to equalise the cell-to-cell current distribution, however if this was placed at a location furthest from the load point this would cause a ~6% reduction in accessible energy at 1.5 C. The influence of thermal gradients can further affect this current heterogeneity leading to accelerated aging. Simulations show that in all cases, cells degrade at different rates in a pack due to the uneven currents, with this being amplified by thermal gradients. In the presented work a 5.2% increase in degradation rate, from -7.71 mWh/cycle (isothermal) to - 8.11 mWh/cycle (non-isothermal) can be observed. Therefore, the insights from this paper highlight the highly coupled nature of battery pack performance and can inform designs for higher performance and longer lasting battery packs