1,063 research outputs found

    A protocol for the large‐scale analysis of reefs using Structure from Motion photogrammetry

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    1. Substrate complexity is an essential metric of reef health and a strong predictor of several ecological processes connected to the reef, including disturbance, resilience, and associated community abundance and diversity. / 2. Underwater Structure from Motion (SfM) photogrammetry has been growing rapidly in use over the last 5 years due to advances in computing power, reduced costs of underwater digital cameras and a push for reproducible data. This has led to the adaptation of an originally terrestrial survey technique into the marine realm, which can now be applied at the habitat scale. / 3. This technique allows researchers to make detailed 3D reconstructions of reef surfaces for morphometric analysis of reef physical structure and perform large‐scale image‐mosaic mapping. SfM is useful for both reef‐scale and colony‐scale assessments, where visual or acoustic methods are impractical or not sufficiently detailed. / 4. Here we provide a protocol for the collection, analysis and display of 3D reef data, focussing on large‐scale habitat assessments of coral reefs using primarily open‐source software. We further suggest applications for other underwater environments and scales of assessment, and hope this standardized protocol will help researchers apply this technology and inspire new avenues of ecological research

    Mushroom to manoeuvre? Using photogrammetry to track the movement and survival of free-living corals

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    Mushroom corals can play an important role in tropical reef ecosystems by providing habitat and performing important ecological functions. Unlike most stony corals, free-living mushroom corals can move, both passively and actively, and can use this ability to escape competition or harmful environments. However, as their movement is typically slow, occurs over relatively small scales, and is traditionally hard to measure, their movement ecology is little researched. Nevertheless, quantitative geospatial data on species’ movement, distribution, survival, and interaction can improve mechanistic modelling of community dynamics in various environments. We use ‘structure from motion’ photogrammetry to track 51 individual corals’ 3D movement and survival over one year within an isolated and enclosed lagoon. This technique essentially provides a large-scale quantitative community time-lapse and allows detailed individual level life-history data to be collected over spatial and temporal scales that were previously impractical

    Determinants of voluntary audit and voluntary full accounts in micro- and non-micro small companies in the UK

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    This is an Author's Accepted Manuscript of an article published in Accounting and Business Research, 42(4), 441 - 468, 2012, copyright Taylor & Francis, available online at: http://www.tandfonline.com/10.1080/00014788.2012.667969.This study investigates the link between the auditing and filing choices made by a sample of 592 small private companies, which includes 419 micro-companies. It examines decisions made in connection with the 2006 accounts following UK's adoption of the maximum EU size thresholds in 2004, and the impact of the proposed Directive on the annual accounts of micro-companies. The research extends the model of cost, management and agency factors associated with voluntary audit, and develops a complementary model for voluntary full accounts. The results show the benefits of placing full audited accounts on public record that outweigh the costs for a significant proportion of companies. In non-micro small companies, voluntary audit is determined by cost and agency factors, whereas in micro-companies it is driven by cost, management and agency factors. In both groups, the predictors of voluntary full accounts include management and agency factors, and choosing voluntary audit is one of the key factors. The study provides models that can be tested in other jurisdictions to provide evidence of the needs of micro-companies, and the discussion of the methodological challenges for small company researchers in the UK makes further contribution to the literature

    Offshore wind: the potential to contribute a quarter of UK electricity by 2024

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    The paper's main conclusion is that by 2024 a major offshore wind programme could be supplying 26% of UK electricity and saving c. 6% of UK carbon emissions. In comparison, by 2024 an expanded nuclear programme of 10 PWRs could supply 23% of current demand and displace c. 5% of carbon emissions. The cost of electricity from offshore wind is likely to be no more than that from nuclear power, including the additional costs of reserve power to cope with the variability of wind. An expanded UK offshore wind industry could support c. 50000 jobs

    Assessment of highly distributed power systems using an integrated simulation approach

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    In a highly distributed power system (HDPS), micro renewable and low carbon technologies would make a significant contribution to the electricity supply. Further, controllable devices such as micro combined heat and power (CHP) could be used to assist in maintaining stability in addition to simply providing heat and power to dwellings. To analyse the behaviour of such a system requires the modelling of both the electrical distribution system and the coupled microgeneration devices in a realistic context. In this paper a pragmatic approach to HDPS modelling is presented: microgeneration devices are simulated using a building simulation tool to generate time-varying power output profiles, which are then replicated and processed statistically so that they can be used as boundary conditions for a load flow simulation; this is used to explore security issues such as under and over voltage, branch thermal overloading, and reverse power flow. Simulations of a section of real network are presented, featuring different penetrations of micro-renewables and micro-CHP within the ranges that are believed to be realistically possible by 2050. This analysis indicates that well-designed suburban networks are likely to be able to accommodate such levels of domestic-scale generation without problems emerging such as overloads or degradation to the quality of supply

    Improved prediction of shell side heat transfer in horizontal evaporative shell and tube heat exchangers

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    This paper presents an improved prediction method for the heat transfer and pressure drop in the shell side of a horizontal shell and tube evaporator. The results from an experimental test program are used in which a wide range of evaporating two-phase shell side flow data was collected from a TEMA E-shell evaporator. The data are compared with shell side heat transfer coefficient and pressure drop models for homogeneous and stratified flow. The comparison suggests a deterioration in the heat transfer data at low mass fluxes consistent with a transition from homogeneous to stratified flow. The pressure drop data suggest a stratified flow across the full test range. A new model is presented that suggests the transition in the heat transfer data may be due to the extent of tube wetting in the upper tube bundle. The new model, which also takes into account the orientation of the shell side baffles, provides a vast improvement on the predictions of a homogenous type model. The new model would enable designers of shell side evaporators/reboilers to avoid operating conditions where poor heat transfer could be expected, and it would also enable changes in process conditions to be assessed for their implications on likely heat transfer performance. (Abstract from WOK

    The digital divide and ICT learning in rural communities:examples of good practice service delivery

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    This article aims to gain a greater understanding of relevant and successful methods of stimulating an ICT culture and skills development in rural areas. The paper distils good practice activities, utilizing criteria derived from a review of the rural dimensions of ICT learning, from a range of relevant initiatives and programmes. These good practice activities cover: community resource centres providing opportunities for ‘tasting’ ICTs; video games and Internet Cafe®s as tools removing ‘entry barriers’; emphasis on ‘user management’ as a means of creating ownership; service delivery beyond fixed locations; use of ICT capacities in the delivery of general services; and selected use of financial support

    Which sectors are driving regional economic development? Comparing the effects of changes in employment in knowledge-based and consumption-based sectors on regional economic performance

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    Despite increasing as a proportion of economic activity, the role of consumption in regional economic development does not feature highly in the policies or debates. Instead, the focus is on the promotion of innovative activity and knowledge assets. Using NUTS 3 level data this paper examines the changing level of employment in consumption-based and knowledge-based sectors in order to assess the contribution of each to regional economic development
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