30 research outputs found

    Effects of ecosystem protection on scallop populations within a community-led temperate marine reserve

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    This study investigated the effects of a newly established, fully protected marine reserve on benthic habitats and two commercially valuable species of scallop in Lamlash Bay, Isle of Arran, United Kingdom. Annual dive surveys from 2010 to 2013 showed the abundance of juvenile scallops to be significantly greater within the marine reserve than outside. Generalised linear models revealed this trend to be significantly related to the greater presence of macroalgae and hydroids growing within the boundaries of the reserve. These results suggest that structurally complex habitats growing within the reserve have substantially increased spat settlement and/or survival. The density of adult king scallops declined threefold with increasing distance from the boundaries of the reserve, indicating possible evidence of spillover or reduced fishing effort directly outside and around the marine reserve. However, there was no difference in the mean density of adult scallops between the reserve and outside. Finally, the mean age, size, and reproductive and exploitable biomass of king scallops were all significantly greater within the reserve. In contrast to king scallops, the population dynamics of queen scallops (Aequipecten opercularis) fluctuated randomly over the survey period and showed little difference between the reserve and outside. Overall, this study is consistent with the hypothesis that marine reserves can encourage the recovery of seafloor habitats, which, in turn, can benefit populations of commercially exploited species, emphasising the importance of marine reserves in the ecosystem-based management of fisheries

    Inertance-Integrated Primary Suspension Optimisation on an Industrial Railway Vehicle Model

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    Improving the track friendliness of a railway vehicle is highly beneficial to the rail industry, as it substantially increases its cost effectiveness. Rail surface damage under curving conditions can be reduced by using vehicles with a reduced Primary Yaw Stiffness (PYS); however, a lower PYS often leads to a reduction in high-speed stability and can negatively impact ride comfort. Previous studies have suggested that this trade-off, between track friendliness and passenger comfort, can be successfully improved by using an inerter in the primary suspension; however, these studies used simplified two-axle vehicles and simplified contact models, and track inputs. Considering a more realistic four-axle passenger vehicle model, this paper investigates the extent to which the PYS can be reduced using inertance-integrated primary lateral suspensions without increasing Root Mean Square (RMS) lateral carbody accelerations when running over a 5 km example track (with a number of vertical, lateral and longitudinal irregularities, and gauge variations). The vehicle, with inertance-integrated primary lateral suspensions, has been modelled inVAMPIRE®\mathrm{VAMPIRE}^{\textregistered }, and the vehicle dynamics are captured over a range of different velocities and wheel-rail equivalent conicities. Several inertance-integrated suspensions are optimised, leading to permissible PYS reductions of up to 47% compared to the original vehicle, whilst lateral carbody accelerations remain at acceptable levels. This level of PYS reduction would result in a potential Network Rail Variable Usage Charge saving of 26%

    2010-2011 world nuclear industry status report

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    In 2010, there were more nuclear power units under construction worldwide than in any year since 1988. Even before Fukushima, however, status indicators for the international nuclear industry were showing a negative trend. Fewer countries are operating nuclear fission reactors for energy purposes than in previous years, and many countries are now past their nuclear peak. Worldwide nuclear production is generally declining, and many new projects are experiencing construction delays. Even if reactors can be operated for an average of 40 years, 74 new plants would have to come on line by 2015 to maintain the status quo, which is impossible given current constraints on fabricating reactor components. Developments in Asia, particularly in China, do not fundamentally change the global picture. The dramatic post-Fukushima decisions in two of the four largest economies, Japan and Germany, and in several other nuclear countries could accelerate the decline of a rapidly aging industry

    The response to the global financial turmoil in Italy: a financial system that does not speak English

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    Addressing the response to the global financial turmoil in Italy, it is argued that in comparison with other financial systems in Europe and worldwide, the Italian financial system has not been dramatically affected by the financial turmoil for two main reasons: the solid framework for financial regulation and supervision and the traditional unsophisticated configuration of financial activities in Italy. However, the economic recession that hit the real economy as a consequence of the financial market turmoil is likely to be heavy and prolonged in Italy

    Implications of using alternative methods of vessel monitoring system (VMS) data analysis to describe fishing activities and impacts

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    Understanding the spatial distribution and intensity of fishing activity is a prerequisite for estimating fishing impacts on seabed biota and habitats. Vessel monitoring system data provide information on fishing activity at large spatial scales. However, successive position records can be too infrequent to describe the complex movements fishing vessels make. High-frequency position data were collected to evaluate how polling frequency and the method of analysis influenced the estimates of fishing impact on the seabed and associated epifaunal communities. Comparisons of known positions with predictions from track interpolation revealed that the performance of interpolation depended on fleet behaviour. Descriptions and indicators of fishing intensity were influenced significantly by the analytical methods (track reconstruction, density of position records) and grid-cell resolution used for the analysis. These factors can lead to an underestimation of fishing impact on epifaunal communities. It is necessary to correct for such errors to quantify the effects of fishing on various ecosystem components and hence to inform ecosystem-based management. Polling at intervals of 30 min would provide a desirable compromise between achieving precise estimates of fishing impacts on the seabed and minimizing the cost of data collection and handling
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