Naresuan University Journal
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Constraining dark sector perturbations I: cosmic shear and CMB lensing
No full textWe present current and future constraints on equations of state for dark sector perturbations. The equations of state considered are those corresponding to a generalized scalar field model and time-diffeomorphism invariant L(g) theories that are equivalent to models of a relativistic elastic medium and also Lorentz violating massive gravity. We develop a theoretical understanding of the observable impact of these models. In order to constrain these models we use CMB temperature data from Planck, BAO measurements, CMB lensing data from Planck and the South Pole Telescope, and weak galaxy lensing data from CFHTLenS. We find non-trivial exclusions on the range of parameters, although the data remains compatible with w = -1. We gauge how future experiments will help to constrain the parameters. This is done via a likelihood analysis for CMB experiments such as CoRE and PRISM, and tomographic galaxy weak lensing surveys, focussing in on the potential discriminatory power of Euclid on mildly non-linear scales
Revisiting Evolving Webs of Agri-food and Rural Development in the UK: The Case of Devon and Shetland
No full textObservation of the rare decay B<sub>s</sub><sup>0</sup>→µ<sup>+</sup>µ<sup>−</sup> from the combined analysis of CMS and LHCb data
No full textEducation, democracy and social change: Venezuela’s education missions in theory and practice
No full textThe ‘Bolivarian Revolution’ in Venezuela is conceptualised as a pedagogical project that aims to develop ‘twenty-first century Socialism’ through state-grassroots collaboration in the reorganisation of political space in order to develop participatory, democratic institutions and processes. The cornerstones of this project to deepen and expand democracy in and through education are the adult Education Missions, set up in parallel to existing educational structures, and with an explicit focus on socio-political education and community projects aimed at promoting a new hegemony based on active grassroots citizenship. While the struggle to extend democracy in and through education is not unique to Venezuela, the conceptualisation of democracy as protagonist and participatory, and the explicit links made between education and democratic social change within the broader framework of twenty-first century socialism, makes Venezuela a dynamic site to revisit and reinvigorate classical debates as to the role of education in promoting democratic social change. Based on 15 months of empirical research, this paper examines the extent to which adult education in Venezuela is contributing to the development of a counter-hegemonic movement to build socialism for the twenty-first century
Comparative Performance of ATRIA, CHADS2, and CHA2DS2-VASc Risk Scores Predicting Stroke in Patients With Atrial Fibrillation: Results From a National Primary Care Database.
No full textBACKGROUND: Previous studies report that CHADS2 and CHA2DS2-VASc risk scores have similar discriminating ability (C statistic ∼0.6). Recently a clinically based risk score, the ATRIA (Anticoagulation and Risk Factors in Atrial Fibrillation) study risk score, was developed and validated. OBJECTIVES: This study compared predictive ability of CHA2DS2-VASc and CHADS2 ischemic stroke risk scores with ATRIA stroke risk score and their implications for anticoagulant treatment in patients with atrial fibrillation (AF). METHODS: Patients with AF not using warfarin were included from the Clinical Practice Research Datalink database, 1998 to 2012. Patients were followed from AF diagnosis until occurrence of ischemic stroke, prescription of warfarin, death, or the study's end. Independent predictors of ischemic stroke were identified and the c-index and net reclassification improvement were calculated. RESULTS: A total of 60,594 patients with AF were included. Annualized stroke rate was 2.99%. Event rates for moderate- and high-risk categories for CHA2DS2-VASc were lower than those of the ATRIA and CHADS2. Age and previous stroke most strongly predicted ischemic stroke. C statistics for the full point scores were 0.70 (95% confidence interval [CI]: 0.69 to 0.71) for the ATRIA risk score, 0.68 (95% CI: 0.67 to 0.69) for CHADS2, and 0.68 (95% CI: 0.67 to 0.69) for CHA2DS2-VASc risk score. The net reclassification improvement was 0.23 (95% CI: 0.22 to 0.25) for ATRIA compared with CHA2DS2-VASc. CONCLUSIONS: The ATRIA score performed better in the U.K. Clinical Practice Research Datalink AF cohort. It more accurately identified low-risk patients than the CHA2DS2-VASc score, which assigned these patients to higher-risk categories. Such reclassification of stroke risk could prevent overuse of anticoagulants in very low stroke risk patients with AF
Travelling wave fault locator for mixed overhead and underground teed transmission feeders
No full textSociety is increasingly concerned about the environmental impact of energy systems, and prefers to locate power lines underground. This is especially true in regions of outstanding natural beauty or if they affect environmental/political/planning constrained areas. However, the use of underground sections within a predominantly overhead feeder introduces significant problems for the auto-reclosure of circuit breakers. Auto-reclosure is important on an overhead feeder, since most faults are transient and, once the feeder has been de-energized, the insulation strength of the air at the fault recovers and the line can be restored to service. Faults on an underground cable are different because, once the insulation is damaged, the fault is normally permanent. In addition, if the breaker is allowed to reclose onto a cable fault, the area of damage increases and health and safety concerns exist for humans in the vicinity of the faulted cable section. The main purpose of the traveling-wave-based measurement scheme described in this paper is to locate a fault on a teed transmission feeder with mixed overhead and underground sections. Simulation results demonstrate that the fault locator can accurately locate all realistic faults, including ones that are high resistance or occur at nonideal points on wave. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc
Performance Characterisation of AGR Fuel Cladding Relevant to Long-term in-Pond Storage in pH-moderated Aqueous Environment
No full textFuel cladding of the UK’s advanced gas-cooled reactors (AGR) is made of 20%Cr/25%Ni–Nb stabilised austenitic stainless steel. The research reported in this paper aims to enhance the mechanistic understanding of AGR fuel cladding performance. Thermal heat treatments were applied to simulate a range of cladding microstructure, including a sensitised and stabilised condition. Oxalic acid metallographic etching and Electron Back-Scattered Diffraction (EBSD) were used to characterise microstructure, augmented by electro-chemical assessments to provide a quantitative measure of the degree of sensitisation. Anodic polarisaiton tests in 500ppm chloride containing aqueous environments at neutral pH and pH 11.5 indicated differences in microstructure corrosion resistance. In neutral environment pitting corrosion is observed in as-received microstructure, inter-granular corrosion initiating at triple junctions in the sensitised microstructures, and localised pitting corrosion at Nb-rich precipitates interfaces in the stabilised microstructure. Whereas at high pH a suppression of corrosion was achieved, supporting the strategy to pH-control storage pond environments. However, microstructure analysis of the sample surfaces after exposure to pH 11.5 solution indicated dissolution of Nb-containing precipitates, which is currently subject of further investigations. The relationship between microstructure conditions, corrosion morphology, with relevance to currently applied corrosion mitigation strategies for in-pond storage of AGR fuel cladding will be elaborated
Decarbonising electricity supply: Is climate change mitigation going to be carried out at the expense of other environmental impacts?
No full textAs nations face the need to decarbonise their energy supply, there is a risk that attention will be focused solely on carbon and climate change, potentially at the expense of other environmental impacts. To explore the trade-offs between climate change mitigation and other environmental impacts, this work focuses on electricity and considers a number of scenarios up to 2070 in a UK context with different carbon reduction targets and electricity demand to estimate the related life cycle environmental impacts. In total, 16 scenarios are discussed, incorporating fossil-fuel technologies with and without carbon capture and storage, nuclear power and a range of renewable options. A freely available model–Electricity Technologies Life Cycle Assessment (ETLCA)–developed by the authors has been used for these purposes. The results suggest that decarbonisation of electricity supply to meet carbon targets would lead to a reduction in the majority of the life cycle impacts by 2070. The exceptions to this are depletion of elements which would increase by 4–145 times and health impacts from radiation which would increase two- to four-fold if nuclear power were used. Ozone layer depletion would also go up in the short-term by between 2.5–3.7 times. If energy demand continued to grow, three other impacts would also increase while trying to meet the carbon targets: human toxicity (two times), photochemical smog (12%) and terrestrial eco-toxicity (2.3 times). These findings demonstrate the importance of considering a broader range of environmental impacts alongside climate change to avoid decarbonising the economy at the expense of other environmental impacts