3,654 research outputs found
Review of meteoroid-bumper interaction studies at McGill University
Experimental investigation of meteoroid-bumper impact, debris cloud expansion, and second surface pressure loadin
Comparing Online and Offline Knowledge Networks of Carbon Capture and Storage
© 2017 The Authors. This paper examines the complex ecosystem of organisations involved in the proposed role out of carbon capture and storage (CCS) in the UK. Through analysis of interview and twitter data, it focuses on the flow of knowledge flows within online and offline networks, highlighting how in this case, CCS retains a niche audience, with communication and information flows concentrated with industry and stakeholder networks at a local and regional scale, as opposed to reaching broader national policy makers, and the wider publics. This brings a unique insight into the construction of networks across intersecting sectors of this critical technology and highlights how for successful implementation CCS, actors may need to reach out beyond their existing network
Consumer responses to a future UK food system
Purpose– The purpose of this paper is to describe research exploring consumer responses to potential changes in food-related practices to mitigate and adapt to climate change.Design/methodology/approach– Six focus groups explored consumer responses to measures to intended to mitigate the emissions from, and adapt to the impacts of climate change. These included: meat reduction, greater reliance on seasonal British food, meal replacement tablets, laboratory grown meat, communal eating houses, genetically modified food and food waste. Practice theory provided the lens to interpret the changes to meanings, competences and materials associated with food consumption.Findings– Changes that could be assimilated within existing competencies were viewed more positively, with lack of competence a key barrier to accommodating change. At present, climate change and sustainability do not influence purchasing decisions. Policy measures delivering multiple benefits (“win-wins”), of which environmental performance may be one, stand an improved chance of establishing more sustainable practices than those focusing exclusively on environmental drivers.Originality/value– Awareness of the role of sustainable food systems in the context of anthropogenic climate change is growing. Whilst scientific and technological research explores methods for reducing emissions and building resilience in food supply chains to changes in climate, there is comparatively little study of how consumers perceive these proposed “solutions”. This research provides a comprehensive overview of consumer responses to potential changes in eating practices related to climate change mitigation and adaptation and is of value to policy makers, academics and practitioners across the food supply chain.</jats:sec
Dynamical q-deformation in quantum theory and the stochastic limit
A model of particle interacting with quantum field is considered. The model
includes as particular cases the polaron model and non-relativistic quantum
electrodynamics. We show that the field operators obey q-commutation relations
with q depending on time. After the stochastic (or van Hove) limit, due to the
nonlinearity, the atomic and field degrees of freedom become entangled in the
sense that the field and the atomic variables no longer commute but give rise
to a new algebra with new commutation relations replacing the Boson ones. This
new algebra allows to give a simple proof of the fact that the non crossing
half-planar diagrams give the dominating contribution in a weak coupling regime
and to calculate explicitly the correlations associated to the new algebra. The
above results depend crucially on the fact that we do not introduce any dipole
or multipole approximation.Comment: Latex, 11 page
A Survey for H2O Megamasers III. Monitoring Water Vapor Masers in Active Galaxies
We present single-dish monitoring of the spectra of 13 extragalactic water
megamasers taken over a period of 9 years and a single epoch of sensitive
spectra for 7 others. Our data include the first K-band science observations
taken with the new 100 m Green Bank Telescope (GBT). In the context of a
circumnuclear, molecular disk model, our results suggest that either (a) the
maser lines seen are systemic features subject to a much smaller acceleration
than present in NGC 4258, presumably because the gas is farther from the
nuclear black hole, or (b) we are detecting ``satellite'' lines for which the
acceleration is in the plane of the sky.
We also report a search for water vapor masers towards the nuclei of 58
highly inclined, nearby galaxies.Comment: accepted by ApJ
Endothelial nitric oxide synthase single nucleotide polymorphism and left ventricular function in early chronic kidney disease
Chronic kidney disease (CKD) is associated with accelerated cardiovascular disease and heart failure. Endothelial nitric oxide synthase (eNOS) Glu298Asp single nucleotide polymorphism (SNP) genotype has been associated with a worse phenotype amongst patients with established heart failure and in patients with progression of their renal disease. The association of a cardiac functional difference in non-dialysis CKD patients with no known previous heart failure, and eNOS gene variant is investigated. Methods 140 non-dialysis CKD patients, who had cardiac magnetic resonance (CMR) imaging and tissue doppler echocardiography as part of two clinical trials, were genotyped for eNOS Glu298Asp SNP retrospectively. Results The median estimated glomerular filtration rate (eGFR) was 50mls/min and left ventricular ejection fraction (LVEF) was 74 with no overt diastolic dysfunction in this cohort. There were significant differences in LVEF across eNOS genotypes with GG genotype being associated with a worse LVEF compared to other genotypes (LVEF: GG 71, TG 76, TT 73, p = 0.006). After multivariate analysis, (adjusting for age, eGFR, baseline mean arterial pressure, contemporary CMR heart rate, total cholesterol, high sensitive C-reactive protein, body mass index and gender) GG genotype was associated with a worse LVEF, and increased LV end-diastolic and systolic index (p = 0.004, 0.049 and 0.009 respectively). Conclusions eNOS Glu298Asp rs1799983 polymorphism in CKD patients is associated with relevant sub-clinical cardiac remodelling as detected by CMR. This gene variant may therefore represent an important genetic biomarker, and possibly highlight pathways for intervention, in these patients who are at particular risk of worsening cardiac disease as their renal dysfunction progresses. © 2015 Chand et al
Application of hot melt extrusion for improving bioavailability of artemisinin a thermolabile drug
Hot melt extrusion has been used to produce a solid dispersion of the thermolabile drug artemisinin. Formulation and process conditions were optimized prior to evaluation of dissolution and biopharmaceutical performance. Soluplus®, a low Tg amphiphilic polymer especially designed for solid dispersions enabled melt extrusion at 110 °C although some drug-polymer incompatibility was observed. Addition of 5% citric acid as a pH modifier was found to suppress the degradation. The area under plasma concentration time curve (AUC0–24h) and peak plasma concentration (Cmax) were four times higher for the modified solid dispersion compared to that of pure artemisinin
PKS 1830-211: A Possible Compound Gravitational Lens
Measurements of the properties of gravitational lenses have the power to tell
us what sort of universe we live in. The brightest known radio Einstein
ring/gravitational lens PKS 1830-211 (Jauncey et al., 1991), whilst obscured by
our Galaxy at optical wavelengths, has recently been shown to contain
absorption at the millimetre waveband at a redshift of 0.89 (Wiklind and
Combes, 1996a). We report the detection of a new absorption feature, most
likely due to neutral hydrogen in a second redshift system at z = 0.19.
Follow-up VLBI observations have spatially resolved the absorption and reveal
it to cover the NE compact component and part of the lower surface brightness
ring. This new information, together with existing evidence of the unusual VLBI
radio structure and difficulties in modeling the lensing system, points to the
existence of a second lensing galaxy along our line of sight and implies that
PKS 1830-211 may be a compound gravitational lens.Comment: 8 pages, 2 figures, LaTeX (aasms4.sty). Accepted for publication in
ApJ Letters. Preprint also available at
http://kerr.phys.utas.edu.au/preprints
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