1,799 research outputs found

    (Looking) Back to the Future: using space-time patterns to better predict the location of street crime

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    Crime analysts attempt to identify regularities in police recorded crime data with a central view of disrupting the patterns found. One common method for doing so is hotspot mapping, focusing attention on spatial clustering as a route to crime reduction (Chainey & Ratcliffe, 2005; Clarke & Eck, 2003). Despite the widespread use of this analytical technique, evaluation tools to assess its ability to accurately predict spatial patterns have only recently become available to practitioners (Chainey, Tompson, & Uhlig, 2008). Crucially, none has examined this issue from a spatio-temporal standpoint. Given that the organisational nature of policing agencies is shift based, it is common-sensical to understand crime problems at this temporal sensitivity, so there is an opportunity for resources to be deployed swiftly in a manner that optimises prevention and detection. This paper tests whether hotspot forecasts can be enhanced when time-of-day information is incorporated into the analysis. Using street crime data, and employing an evaluative tool called the Predictive Accuracy Index (PAI), we found that the predictive accuracy can be enhanced for particular temporal shifts, and this is primarily influenced by the degree of spatial clustering present. Interestingly, when hotspots shrank (in comparison with the all-day hotspots), they became more concentrated, and subsequently more predictable. This is meaningful in practice; for if crime is more predictable during specific timeframes, then response resources can be used intelligently to reduce victimisation

    Fisheries Stakeholders and Their Livelihoods in Tamil Nadu and Puducherry

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    Fisheries Management for Sustainable Livelihoods (FIMSUL), is a project implemented by the Food and Agriculture Organization of the United Nations (FAO) with the Government of Tamil Nadu and Puducherry in India under the World Bank Trust Fund. The project aims at establishing frameworks, processes and building capacities of various stakeholders especially the Government, to facilitate the planning, design and implementation of appropriate fisheries development and management policies. The project includes a series of stakeholder consultations and consensus building apart from detailed review and analysis in the areas of stakeholders, livelihoods, policy, legal and institutional frame work and fisheries management. Based on this, the project comes up with various options. Stakeholder and livelihoods analysis is an essential part of the project. Hence, the team developed a detailed methodology for stakeholder consultations which includes district level stake holder consultation, focus group discussions, household interviews and validation meetings. The stakeholder and livelihoods analysis following the above steps were done through six NGO partners working along the coast of Tamil Nadu and Puducherry who were initially trained on the methodology. The NGO partners : PLANT, GUIDE, FERAL, SIFFS, DHAN Foundation and TMSSS, especially a team of dedicated staff engaged by them had done an excellent work in completing comprehensive field exercises and bringing out 12 district/regional reports. These are published separately. This report is a compilation, and complete analysis of the stakeholders and livelihoods based on all the field level consultations.This report is expected to be an important reference to primary stakeholders' perspective of the important stakeholders in the sector, the livelihoods and livelihoods changes, the adaptive and coping mechanism, the relationships between the stakeholders and their hopes and aspirations. For any development intervention for any sector or stakeholder group, region-wise in marine fisheries in Tamil Nadu and Puducherry, the information from this report could be an important starting point

    Power-Law Wrinkling Turbulence-Flame Interaction Model for Astrophysical Flames

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    We extend a model for turbulence-flame interactions (TFI) to consider astrophysical flames with a particular focus on combustion in type Ia supernovae. The inertial range of the turbulent cascade is nearly always under-resolved in simulations of astrophysical flows, requiring the use of a model in order to quantify the effects of subgrid-scale wrinkling of the flame surface. We provide implementation details to extend a well-tested TFI model to low-Prandtl number flames for use in the compressible hydrodynamics code FLASH. A local, instantaneous measure of the turbulent velocity is calibrated for FLASH and verification tests are performed. Particular care is taken to consider the relation between the subgrid rms turbulent velocity and the turbulent flame speed, especially for high-intensity turbulence where the turbulent flame speed is not expected to scale with the turbulent velocity. Finally, we explore the impact of different TFI models in full-star, three-dimensional simulations of type Ia supernovae.Comment: 20 pages, 12 figures, accepted to the Astrophysical Journa

    Chandra X-ray observation of the HII region Gum 31 in the Carina Nebula complex

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    (abridged) We used the Chandra observatory to perform a deep (70 ksec) X-ray observation of the Gum 31 region and detected 679 X-ray point sources. This extends and complements the X-ray survey of the central Carina nebula regions performed in the Chandra Carina Complex Project. Using deep near-infrared images from our recent VISTA survey of the Carina nebula complex, our Spitzer point-source catalog, and optical archive data, we identify counterparts for 75% of these X-ray sources. Their spatial distribution shows two major concentrations, the central cluster NGC 3324 and a partly embedded cluster in the southern rim of the HII region, but majority of X-ray sources constitute a rather homogeneously distributed population of young stars. Our color-magnitude diagram analysis suggests ages of ~1-2 Myr for the two clusters, whereas the distributed population shows a wider age range up to ~10 Myr. We also identify previously unknown companions to two of the three O-type members of NGC 3324 and detect diffuse X-ray emission in the region. Our results suggests that the observed region contains about 4000 young stars in total. The distributed population is probably part of the widely distributed population of ~ 1-10 Myr old stars, that was identified in the CCCP area. This implies that the global stellar configuration of the Carina nebula complex is a very extended stellar association, in which the (optically prominent) clusters contain only a minority of the stellar population.Comment: Accepted for publication in Astronomy & Astrophysics. A high quality preprint is available at http://www.usm.uni-muenchen.de/people/preibisch/publications.htm
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