Ab-initio electron scattering cross-sections and transport in liquid xenon

Ab-initio electron - liquid phase xenon fully differential cross-sections for electrons scattering in liquid xenon are developed from a solution of the Dirac-Fock scattering equations, using a recently developed framework [1] which considers multipole polarizabilities, a non-local treatment of exchange, and screening and coherent scattering effects. A multi-term solution of Boltzmann's equation accounting for the full anisotropic nature of the differential cross-section is used to calculate transport properties of excess electrons in liquid xenon. The results were found to agree to within 25% of the measured mobilities and characteristic energies over the reduced field range of 10^{-4} to 1 Td. The accuracies are comparable to those achieved in the gas phase. A simple model, informed by highly accurate gas-phase cross-sections, is presented to transform highly accurate gas-phase cross-sections to improve the liquid cross-sections, which was found to enhance the accuracy of the transport coefficient calculations.Comment: 26 pages, 9 figures. arXiv admin note: text overlap with arXiv:1503.0037

Psychological therapies for depression and cardiovascular risk: evidence from national healthcare records in England

Aims: People with depression are up to 72% more at risk to develop cardiovascular disease (CVD) in their lifetime. Evidence-based psychotherapies are first-line interventions for the treatment of depression and are delivered nationally in England through the National Health Service via the Improving Access to Psychological Therapy (IAPT) primary care programme. It is currently unknown whether positive therapy outcomes may be associated with cardiovascular risk reduction. This study aimed to examine the association between psychotherapy outcomes for depression and incident CVD. Methods and results: A cohort of 636 955 individuals who have completed a course of psychotherapy was built from linked electronic healthcare record databases of national coverage in England: the national IAPT database, the Hospital Episode Statistics (HES) database, and the HES–ONS (Office of National Statistics) mortality database. Multivariable Cox models adjusting for clinical and demographic covariates were run to estimate the association between reliable improvement from depression and the risk of subsequent incidence of cardiovascular events. After a median follow-up of 3.1 years, reliable improvement from depression symptoms was associated with a lower risk of new onset of any CVD [hazard ratio (HR): 0.88, 95% confidence interval (CI): 0.86, 0.89], coronary heart disease (HR: 0.89, 95% CI: 0.86, 0.92), stroke (HR: 0.88, 95% CI: 0.83, 0.94), and all-cause mortality (HR: 0.81, 95% CI: 0.78, 0.84). This association was stronger in the under 60 compared with the over 60 for all outcomes. Results were confirmed in sensitivity analyses. Conclusion: Management of depression through psychological interventions may be associated with reduced risk of CVD. More research is needed to understand the causality of these associations

Interactions of hydrology, geochemistry, and biodiversity in woodland ponds located in riverine floodplains: case study from Scotland

The Gore Glen pond is located in the forested floodplain of the Gore River, in the Mid-Lothian region near Edinburgh, Scotland. This work has considered in detail the hydrology, hydrochemistry, and biodiversity of the pond together with all their interactions and in addition interactions with the adjacent Gore River. It is important as it is one of few studies considering all these issues for a pond located in a riverine floodplain. This work shows the pond is connected to the Gore River for discharge events in the river larger than a 1 in 5-year return period. For these events, the pond acts as an online storage feature and will attenuate the flow, thus contributing towards the mitigation of downstream flooding. These large events are also a potential source of the large amount of sediments, as well as adsorbed chemicals, accumulated in the pond. The open water surface of the pond is covered by duckweed, Lemna minor, for most of the year, and that has profound implications for the hydrobiological community and biogeochemical cycling. The system is characterised by nutrient release from sediments due to the extensive hypolimnion anoxia in the summer/autumn period caused by the decomposition of organic matter. Algae are mostly represented by epiphytic diatoms and the cyanobacterium Microcystis, but their development appears to be constrained by light penetration. The eutrophic conditions are also conducive for the population of Difflugia (Protozoa, Rhizopoda). This work improves our understanding of the ecological relations of testate amoebae—an important group which has recently been used as biological indicators for the analysis of paleoecological relationships and paleogeographical reconstructions.</p

Phytoplankton Image Denoising and Texture Analysis Based on Dual-tree Complex Wavelet Transform

海洋浮游植物的形态分析和分类鉴定是海洋生物资源调查、赤潮和海洋水质监测、水产养殖、地质勘探、薇藻培养和医药开发的重要基础。海洋浮游植物显微图像的分析与分类鉴定是海洋科学与信息技术的重要交叉研究课题，近几年在全球范围内得到关注并持续发展。由于海洋浮游植物的种类及形态的多样性、显微成像过程的干扰，所研制的海洋浮游植物显微图像自动分析与分类鉴定系统还需持续改进。本文针对海洋浮游植物显微图像的去噪和纹理分析这两个问题，探讨双树复小波理论工具在这两个问题中的应用方法，在具体算法实现过程中采取了若干改进措施，提高了应用有效性。本文的主要工作包括： 1.双树复小波的基础理论与应用适应性分析。小波变换具有多...The morphological analysis and identification of marine phytoplankton species from microscopic images is essential to many research and production activities, such as marine resources investigation, red tide monitoring, aquaculture, geological prospecting, microalgae cultivation, medicine development. The analysis and identification of phytoplankton image is a prosperous interdisciplinary subject ...学位：工学硕士院系专业：信息科学与技术学院计算机科学系_计算机应用技术学号：2302008115324

Intelligent agents in computer games

As computer games become more complex and consumers demand more sophisticated computer controlled opponents, game developers are required to place a greater emphasis on the artificial intelligence aspects of their games. Our experience developing intelligent air combat agents for DARPA (Laird and Jones 1998, Tambe, Johnson, Jones, Koss, Laird, Rosenbloom, and Schwamb 1995) has suggested a number of areas of AI research that are applicable to computer games. Research in areas such as intelligent agent architectures, knowledge representation, goal-directed behavior and knowledge reusability are all directly relevant to improving the intelligent agents in computer games. The Soar/Game

The stratigraphy of the youngest part of the Kimmeridge Clay Formation (Upper Jurassic) of the Dorset type area

The lithostratigraphy of the youngest part of the Kimmeridge Clay of the stratotype section at Houns-tout/Chapman's Pool in south Dorset is described in detail for the first time, and is the correlated with other current exposures in south Dorset and with borehole sequences in more distant areas. The stratotype section, albeit deeply weathered in part, is the only complete succession in Britain through this late Jurassic interval. It remains of key importance to international correlation of the Boreal, Sub-boreal and Tethyan faunal provinces at this stratigraphical level and to the resolution of the debate concerning the boundaries of the Kimmeridgian, Tethyan and Bolonian stages

Ecosystem services provided by urban ponds and green spaces: a detailed study of a semi-natural site with global importance for research

Ponds and the adjacent green spaces are an important part of urban blue-green Infrastructure (BGI) and contribute to a number of ecosystem services, including alleviation of flood risk, amelioration of climatic fluctuations, and improvement of runoff water quality, as well as biodiversity and amenity values. Multiple benefits associated with urban ponds have only recently started to be appreciated, and examples of in-depth interdisciplinary insights remain rare. This paper gives an account of the ecosystem services provided by Blackford Pond, a semi-natural water body located within a nature reserve and nominated as a site globally important for scientific research. Despite elevated levels of polluting substances and eutrophication, the overall species richness of the site is high and the biodiversity of the locality is enhanced by the ecotone effect. The diversity of available plant hosts and substrates appears to benefit the fungal community and the abundance of aquatic invertebrate fauna appears to benefit the higher trophic levels. Hydrological modelling clearly shows that the pond increases the flood resilience of the surrounding area, despite not having been designed as a drainage feature. The application of the Natural Capital Planning Tool (NCPT) also reveals higher values (in relation to the values of amenity grassland) of such ecosystem services categories as biodiversity (+4.76 per hectare), aesthetic values (+4.67), flood risk regulation (+0.41), air quality (+0.28), local (+0.6) and global (+0.14) climate regulations. The discussion highlights a number of trade-offs among different ecosystem services (e.g. water quality vs. diatom research value, flood resilience vs. air quality and carbon capture, biodiversity of ectomycorrhizal vs. lichenised fungi), and considers which of the multiple benefits provided by the site may have not been fully reflected in NCPT calculations or the economic estimates obtained using contingent valuation (e.g. effects on hydrology, water quality, wildlife corridors, education and research value). The simultaneous consideration of biodiversity, hydrology, water chemistry and amenity, education, research and other values presented in this paper contributes towards a better understanding of the ecology and overall functioning of urban ponds, and helps to increase appreciation of their benefits and promote their public acceptability and further implementation