2,520 research outputs found
You have declared a climate emergency...now what? Exploring climate action, energy planning and participatory place branding in Canada
The negative impacts of climate change are becoming increasingly clear and cities around the world are a driving force behind these problems, accounting for over 70% of all greenhouse gas emissions. In recognition of the need to act quickly, over 2300 jurisdictions, including 653 in Canada, have recently made climate emergency declarations (CEDs). Yet because most of these CEDs have only been made over the past few years, very little research has been completed focused on what cities are doing after making these decisions. Informed by a literature review on CEDs, urban governance, citizen engagement, communication and place branding strategies, we seek to advance understanding in this important area. To do so, we present a study that centered around two Decision Theatre workshops conducted with climate, energy and communication professionals (n=12) working for or with local governments in four Canadian cities that have declared CEDs. Workshops were transcribed and analyzed via thematic analysis to identify and understand a series of solutions and challenges facing cities. The top solutions recorded were creating targets/action plans, the importance of collaboration, and sharing information with communities. The top two challenges identified were the diversity of city staff and getting the message out. The study closes with a discussion of the broader implications of this work, including recommendations for cities and calls for future research in this critical area
Thermostructural Evaluation of Joggle Region on the Shuttle Orbiter's Wing Leading Edge
An investigation was initiated to determine the cause of coating spallation occurring on the Shuttle Orbiter's wing leading edge panels in the slip-side joggle region. The coating spallation events were observed, post flight, on differing panels on different missions. As part of the investigation, the high re-entry heating occurring on the joggles was considered here as a possible cause. Thus, a thermostructural evaluation was conducted to determine the detailed state-of-stress in the joggle region during re-entry and the feasibility of a laboratory test on a local joggle specimen to replicate this state-of-stress. A detailed three-dimensional finite element model of a panel slip-side joggle region was developed. Parametric and sensitivity studies revealed significant stresses occur in the joggle during peak heating. A critical interlaminar normal stress concentration was predicted in the substrate at the coating interface and was confined to the curved joggle region. Specifically, the high interlaminar normal stress is identified to be the cause for the occurrence of failure in the form of local subsurface material separation occurring in the slip-side joggle. The predicted critical stresses are coincident with material separations that had been observed with microscopy in joggle specimens obtained from flight panels
Assessing the Variation in Rail Interoperability in 11 European Countries, and Barriers to its Improvement
Work conducted within REORIENT, a Sixth Framework project for the European Commission (EC), is described. One objective of REORIENT was to explain the status of transformation of the European railway sector into a functionally integrated, liberalized, interoperable system. The status of interoperability within and between eleven countries in a corridor stretching from Greece to the Nordic countries was assessed, and conditions in the countries that appear to be barriers to achieving the EC’s goals were identified. (Barriers were defined as shortcomings in conditions that would facilitate the implementation of requirements presumed by the EC to lead to seamless international freight transport (“implementation conditions”)). The primary data source for the analysis was a set of interviews with the major actors and stakeholders associated with each country’s rail freight system. The (qualitative) information from the interviews was translated into numeric scores, which were subjected to statistical analysis. The primary objective of the statistical analysis was to provide an assessment of the relationships between the requirements and the implementation conditions. The statistical analysis involved both the identification of relevant relationships and an assessment of the strength of these relationships. Overall, we found that there was considerable variation in interoperability status across the countries on practically all of the requirements. However, there was also considerable variation in the status of the implementation conditions across the countries. As a result, we found that most of the variability was able to be explained by relationships that were found to exist between the requirements and implementation conditions. A ‘Barrier Significance Score’ (BSS) was computed for each country and for each implementation condition. These scores were used to assess the relative importance of barriers across the countries, and to identify the most critical barriers to be removed in order to improve interoperability. Large differences in BSS’s were found among countries. In general there are fewer barriers in Nordic countries and more barriers in the south
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The use of the Continuously Regenerating Trap (CRT<sup>TM</sup>) and SCRT<sup>TM</sup> Systems to meet future emissions legislation
The progressive tightening of particulate matter (PM) legislation presents challenges to the engine development and aftertreatment communities. The Continuously Regenerating Trap (CRTTM) has been developed to enable diesel engines to meet the proposed future legislation. This passive filter system combines an oxidation catalyst with a Diesel Particulate Filter (DPF); the filter traps the PM and the oxidation catalyst generates NO2 which combusts the trapped PM at substantially lower temperatures than is possible using oxygen.
This paper outlines the operating principle of the CRTTM, and describes the performance of the system. It has been shown that the very high PM conversions obtained with the CRTTM can enable even Euro 1 engines to meet the PM limits proposed for introduction in Europe in 2005. In addition, the system removes PM across the whole particle size range, including ultrafine particulates. These results will be discussed, as will in-field durability studies which have shown that the system is still capable of converting 90% of PM after very high mileage operation (up to 600,000 km).
In addition to requiring very high PM conversion, the proposed future legislation requires substantial reductions in NOx emissions form heavy duty diesel vehicles. To meet these challenges the SCRTTM has been developed. This combines the CRTTM with SCR (Selective Catalytic Reduction) technology, and enables very high simultaneous conversions of CO, HC, PM and NOx to be achieved. The SCRTTM system is described, and its operating characteristics are discussed. It has been shown that the SCRTTM can potentially meet the legislative limits proposed for introduction in Europe in 2008
Short-term genome stability of serial Clostridium difficile ribotype 027 isolates in an experimental gut model and recurrent human disease
Copyright: © 2013 Eyre et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are creditedClostridium difficile whole genome sequencing has the potential to identify related isolates, even among otherwise indistinguishable strains, but interpretation depends on understanding genomic variation within isolates and individuals.Serial isolates from two scenarios were whole genome sequenced. Firstly, 62 isolates from 29 timepoints from three in vitro gut models, inoculated with a NAP1/027 strain. Secondly, 122 isolates from 44 patients (2–8 samples/patient) with mostly recurrent/on-going symptomatic NAP-1/027 C. difficile infection. Reference-based mapping was used to identify single nucleotide variants (SNVs).Across three gut model inductions, two with antibiotic treatment, total 137 days, only two new SNVs became established. Pre-existing minority SNVs became dominant in two models. Several SNVs were detected, only present in the minority of colonies at one/two timepoints. The median (inter-quartile range) [range] time between patients’ first and last samples was 60 (29.5–118.5) [0–561] days. Within-patient C. difficile evolution was 0.45 SNVs/called genome/year (95%CI 0.00–1.28) and within-host diversity was 0.28 SNVs/called genome (0.05–0.53). 26/28 gut model and patient SNVs were non-synonymous, affecting a range of gene targets.The consistency of whole genome sequencing data from gut model C. difficile isolates, and the high stability of genomic sequences in isolates from patients, supports the use of whole genome sequencing in detailed transmission investigations.Peer reviewe
Interrogating a Hexokinase-Selected Small-Molecule Library for Inhibitors of Plasmodium falciparum Hexokinase
This is the published version.Parasites in the genus Plasmodium cause disease throughout the tropic and subtropical regions of the world. P. falciparum, one of the deadliest species of the parasite, relies on glycolysis for the generation of ATP while it inhabits the mammalian red blood cell. The first step in glycolysis is catalyzed by hexokinase (HK). While the 55.3-kDa P. falciparum HK (PfHK) shares several biochemical characteristics with mammalian HKs, including being inhibited by its products, it has limited amino acid identity (∼26%) to the human HKs, suggesting that enzyme-specific therapeutics could be generated. To that end, interrogation of a selected small-molecule library of HK inhibitors has identified a class of PfHK inhibitors, isobenzothiazolinones, some of which have 50% inhibitory concentrations (IC50s) of <1 μM. Inhibition was reversible by dilution but not by treatment with a reducing agent, suggesting that the basis for enzyme inactivation was not covalent association with the inhibitor. Lastly, six of these compounds and the related molecule ebselen inhibited P. falciparum growth in vitro (50% effective concentration [EC50] of ≥0.6 and <6.8 μM). These findings suggest that the chemotypes identified here could represent leads for future development of therapeutics against P. falciparum
Polarization and relaxation of radon
Investigations of the polarization and relaxation of Rn by spin
exchange with laser optically pumped rubidium are reported. On the order of one
million atoms per shot were collected in coated and uncoated glass cells.
Gamma-ray anisotropies were measured as a signal of the alignment (second order
moment of the polarization) resulting from the combination of polarization and
quadrupole relaxation at the cell walls. The temperature dependence over the
range 130C to 220C shows the anisotropies increasing with
increasing temperature as the ratio of the spin exchange polarization rate to
the wall relaxation rate increases faster than the rubidium polarization
decreases. Polarization relaxation rates for coated and uncoated cells are
presented. In addition, improved limits on the multipole mixing ratios of some
of the main gamma-ray transitions have been extracted. These results are
promising for electric dipole moment measurements of octupole-deformed
Rn and other isotopes, provided sufficient quantities of the rare
isotopes can be produced.Comment: 4 pages, 4 figure
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