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

Methanol Masers as Tracers of Circumstellar Disks

We show that in many methanol maser sources the masers are located in lines, with a velocity gradient along them which suggests that the masers are situated in edge-on circumstellar, or protoplanetary, disks. We present VLBI observations of the methanol maser source G309.92+0.48, in the 12.2 GHz transition, which confirm previous observations that the masers in this source lie along a line. We show that such sources are not only linear in space but, in many cases, also have a linear velocity gradient. We then model these and other data in both the 6.7 GHz and the 12.2 GHz transition from a number of star formation regions, and show that the observed spatial and velocity distribution of methanol masers, and the derived Keplerian masses, are consistent with a circumstellar disk rotating around an OB star. We consider this and other hypotheses, and conclude that about half of these methanol masers are probably located in edge-on circumstellar disks around young stars. This is of particular significance for studies of circumstellar disks because of the detailed velocity information available from the masers.Comment: 38 pages, 13 figures accepted by Ap