Vortex -- Kink Interaction and Capillary Waves in a Vector Superfluid

Interaction of a vortex in a circularly polarized superfluid component of a 2d complex vector field with the phase boundary between superfluid phases with opposite signs of polarization leads to a resonant excitation of a ``capillary'' wave on the boundary. This leads to energy losses by the vortex--image pair that has to cause its eventual annihilation.Comment: LaTeX 7 pages, no figure

Variation of turbulent burning rate of methane, methanol, and iso-octane air mixtures with equivalence ratio at elevated pressure

Turbulent burning velocities for premixed methane, methanol, and iso-octane/air mixtures have been experimentally determined for an rms turbulent velocity of 2 m/s and pressure of 0.5 MPa for a wide range of equivalence ratios. Turbulent burning velocity data were derived using high-speed schlieren photography and transient pressure recording; measurements were processed to yield a turbulent mass rate burning velocity, utr. The consistency between the values derived using the two techniques, for all fuels for both fuel-lean and fuel-rich mixtures, was good. Laminar burning measurements were made at the same pressure, temperature, and equivalence ratios as the turbulent cases and laminar burning velocities and Markstein numbers were determined. The equivalence ratio (φ) for peak turbulent burning velocity proved not always coincident with that for laminar burning velocity for the same fuel; for isooctane, the turbulent burning velocity unexpectedly remained high over the range φ = 1 to 2. The ratio of turbulent to laminar burning velocity proved remarkably high for very rich iso-octane/air and lean methane/air mixtures

Real Time Turbulent Video Perfecting by Image Stabilization and Super-Resolution

Image and video quality in Long Range Observation Systems (LOROS) suffer from atmospheric turbulence that causes small neighbourhoods in image frames to chaotically move in different directions and substantially hampers visual analysis of such image and video sequences. The paper presents a real-time algorithm for perfecting turbulence degraded videos by means of stabilization and resolution enhancement. The latter is achieved by exploiting the turbulent motion. The algorithm involves generation of a reference frame and estimation, for each incoming video frame, of a local image displacement map with respect to the reference frame; segmentation of the displacement map into two classes: stationary and moving objects and resolution enhancement of stationary objects, while preserving real motion. Experiments with synthetic and real-life sequences have shown that the enhanced videos, generated in real time, exhibit substantially better resolution and complete stabilization for stationary objects while retaining real motion.Comment: Submitted to The Seventh IASTED International Conference on Visualization, Imaging, and Image Processing (VIIP 2007) August, 2007 Palma de Mallorca, Spai

Visual Climate Change Communication: From Iconography To Locally Framed 3D Visualization

Climate change is an urgent problem with implications registered not only globally, but also on national and local scales. It is a particularly challenging case of environmental communication because its main cause, greenhouse gas emissions, is invisible. The predominant approach of making climate change visible is the use of iconic, often affective, imagery. Literature on the iconography of climate change shows that global iconic motifs, such as polar bears, have contributed to a public perception of the problem as spatially and temporally remote. This paper proposes an alternative approach to global climate change icons by focusing on recognizable representations of local impacts within an interactive game environment. This approach was implemented and tested in a research project based on the municipality of Delta, British Columbia. A major outcome of the research is Future Delta, an interactive educational game featuring 3D visualizations and simulation tools for climate change adaptation and mitigation future scenarios. The empirical evaluation is based on quantitative pre/post-game play questionnaires with 18 students and 10 qualitative expert interviews. The findings support the assumption that interactive 3D imagery is effective in communicating climate change. The quantitative post-questionnaires particularly highlight a shift in support of more local responsibility

Population-genomic insights into emergence, crop-adaptation, and dissemination of Pseudomonas syringae pathogens

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Many bacterial pathogens are well characterized but, in some cases, relatively little is known about the populations from which they emerged. This limits understanding of the molecular mechanisms underlying disease. The crop pathogen Pseudomonas syringae sensu lato has been widely isolated from the environment, including wild plants and components of the water cycle, and causes disease in several economically important crops. Here, we compared genome sequences of 45 P. syringae crop pathogen outbreak strains with 69 closely related environmental isolates. Phylogenetic reconstruction revealed that crop pathogens emerged many times independently from environmental populations. Unexpectedly, differences in gene content between environmental populations and outbreak strains were minimal with most virulence genes present in both. However, a genome-wide association study identified a small number of genes, including the type III effector genes hopQ1 and hopD1, to be associated with crop pathogens, but not with environmental populations, suggesting that this small group of genes may play an important role in crop disease emergence. Intriguingly, genome-wide analysis of homologous recombination revealed that the locus Psyr 0346, predicted to encode a protein that confers antibiotic resistance, has been frequently exchanged among lineages and thus may contribute to pathogen fitness. Finally, we found that isolates from diseased crops and from components of the water cycle, collected during the same crop disease epidemic, form a single population. This provides the strongest evidence yet that precipitation and irrigation water are an overlooked inoculum source for disease epidemics caused by P. syringae.Caroline L. Monteil received support from INRA and the European Union, in the framework of the Marie-Curie FP7 COFUND People Programme, through the award of an AgreenSkills’ fellowship (under grant agreement n° 267196). Research in Boris A. Vinatzer’s laboratory and genome sequencing was funded by the National Science Foundation of the USA (grants IOS-1354215 and DEB-1241068). Funding for work in the Vinatzer laboratory was also provided in part by the Virginia Agricultural Experiment Station and the Hatch Program of the National Institute of Food and Agriculture, U.S. Department of Agriculture. Work carried out in the Sheppard laboratory was supported by the Medical Research Council (MRC) grant MR/L015080/1, and the Wellcome Trust grant 088786/C/09/Z. GM was supported by a NISCHR Health Research Fellowship (HF-14-13)

Review of the effectiveness of on-site habitat management to reduce atmospheric nitrogen deposition impacts on terrestrial habitats

1. Given the widespread impacts on habitats in the UK it is essential to understand how habitat management measures could mitigate N deposition impacts and promote recovery. This project reviews the effectiveness of ‘on-site’ land management methods to mitigate nitrogen deposition impacts on sensitive habitats; assesses what effect current management practice has on habitat response to nitrogen deposition; considers how measures may be affected by climate change; and recommends realistic and practical management measures for different habitat types which could be used to mitigate nitrogen impacts or speed recovery. 2. The potential for management to mitigate N deposition impacts was considered across the following broad habitats: broadleaved, mixed and yew woodland & (natural) coniferous woodland; neutral grassland; calcareous grassland; acid grassland; dwarf shrub heath; bog; coastal dunes and slacks; other coastal habitats. For all habitats we were able to identify management techniques with some potential to mitigate N deposition impacts. 3. Management techniques may improve habitat suitability (e.g. control dominant species), remove nitrogen from the system, or both. 4. However, all management techniques also have unintended consequences meaning that their implementation might conflict with other conservation priorities. 5. There are a range of schemes and handbooks providing habitat management advice in the UK. The following techniques were reviewed in detail: grazing; cutting; burning; fertilisation; liming; hydrological management; scrub and tree management; disturbance. 6. Current management may already be partially offsetting the impact of N deposition. 7. Management for N is unlikely to make habitats more vulnerable to climate change. There is complementarity in the management options required to tackle N deposition and climate change. The frequency or intensity of measures such as grazing, cutting or burning will all need to increase. Regional variation in climate change may lead to different emphasis of management options in the wetter north west and the drier south east. 8. Climate change will alter habitat sensitivity to N deposition, via changes in ecosystem processes. Overall, climate change will make woodlands less sensitive to N deposition, but will make heathlands more sensitive to N deposition. Effects on other habitats have not yet been evaluated. 9. There is some potential for mitigating the impacts of N deposition through on-site management although this varies greatly between habitat and management practice. It is likely that small changes in management and adherence to appropriate guidelines could partially improve habitat suitability and/or increase N removal. 10. The majority of management practices do not remove significant quantities of N (with the exception of removing biomass or topsoil). Furthermore, management of a suitable intensity to remove sufficient N to fully offset N added by atmospheric deposition is likely to damage the habitat and result in a number of unintended consequences. 11. Further research is needed to determine the impacts of individual management practices on the N budget in different habitats. Further research is also needed to explore the potential for novel management techniques to remove N from sites. 12. For an individual site where N is identified as a pressure, a manager can look at current management and compare this with the management recommendations in the report to make changes where appropriate. 13. All management recommendations that remove N from the site move it elsewhere and have the potential for unintended consequences. Consequently there is no substitute for reducing the amount of N deposited onto a site which can only be achieved through emission controls