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31.
This paper presents the findings of risk identification and risk perception research conducted in relation to the fisheries systems of four distinct and diverse European countries: Faroes, Iceland, Greece and the UK. Risk research traditionally attempts to quantify the potential threat or consequences from a range of risk events or hazards. This research, however, adopted a social sciences perspective and so assumed that a risk event or hazard can mean different things to different people and that these perceptions are also context and culturally dependent. Risk perceptions were examined and risk registers developed in each country for a range of stakeholder groups. A ‘mental modelling’ approach was adopted in a series of qualitative interviews. Findings were examined in terms of a wide range of psychological, social and cultural risk theories. Differences in risk perceptions were noted between stakeholder groups and countries and contextual influences were examined such as the widely differing fisheries management systems used in each country. This research provides one of the first attempts to systematically evaluate risks and perceptions across a range of fisheries-systems. The findings support social science theories which argue that risk is a subjective, as opposed to objective, concept and that this subjectivity will therefore affect our attempts to assess and manage those hazards we think we can potentially influence or control.  相似文献   
32.
The COREPOINT (COastal REsearch and POlicy INTegration) project aimed to advance integrated coastal zone management (ICZM) in northwest Europe through a network of local authorities, research organisations and NGOs. It involved 12 partners from Ireland, the United Kingdom, France, Netherlands and Belgium. The project enabled a comparison of approaches to ICZM at the northwest Europe scale and a series of workshops was hosted to promote the principles contained in the European Union's recommendation on ICZM. At the local level, linkages were formed between research organisations and coastal management practitioners in local authorities in an attempt to bridge the science-management divide. This special edition contains several papers that deal with different facets of the project's results.  相似文献   
33.
Recent observations over the Sigsbee Escarpment in the Gulf of Mexico have revealed extremely energetic deep currents (near 1 m s−1), which are trapped along the escarpment. Both scientific interest and engineering needs demand dynamical understanding of these extreme events, and can benefit from a numerical model designed to complement observational and theoretical investigations in this region of complicated topography. The primary objective of this study is to develop a modeling methodology capable of simulating these physical processes and apply the model to the Sigsbee Escarpment region. The very steep slope of the Sigsbee Escarpment (0.05–0.1) limits the application of ocean models with traditional terrain-following (sigma) vertical coordinates, which may represent the very complicated topography in the region adequately, can result in large truncation errors during calculation of the horizontal pressure gradient. A new vertical coordinate system, termed a vanishing quasi-sigma coordinate, is implemented in the Navy Coastal Ocean Model for application to the Sigsbee Escarpment region. Vertical coordinate surfaces for this grid have noticeably gentler slopes than a traditional sigma grid, while still following the terrain near the ocean bottom. The new vertical grid is tested with a suite of numerical experiments and compared to a classical sigma-layer model. The numerical error is substantially reduced in the model with the new vertical grid. A one-year, realistic, numerical simulation is performed to simulate strong, deep currents over the Escarpment using a very-high-resolution nested modeling approach. The model results are analyzed to demonstrate that the deep-ocean currents in the simulation replicate the prominent dynamical features of the observed intense currents in the region.  相似文献   
34.
Natural wetlands perform significant sewage treatment, but artificial reedbeds are likely to be more reliable and effective. The processes responsible for purification in wetlands and reedbeds are described in this paper, together with an outline of the experimental reedbeds which have been established in the UK up to 1987. Major research needs are outlined.  相似文献   
35.
The city of Lincoln draws water from a well field along the banks of the Platte River in east-central Nebraska. We have been able to follow the infusion of atrazine into this well field under induced recharge. Samples of water from the river, several monitoring wells and a production well were analyzed by GC/MS and solid phase extraction and found to change in concentration over the range 0.1 and 5.0 ppb of atrazine through the spring, summer, and fall 1989. Increases in the concentration of atrazine relating to precipitation events in the Platte River Basin were observable in the well water samples and ultimately in Lincoln municipal tap water. Atrazine from the river was seen to move via induced recharge and into well field ground water and away from the river at an observable rate. The concentration of atrazine in the river is dependent upon time of year and precipitation in the river basin.  相似文献   
36.
This paper discusses the importance of testing models which may be used to forecast the impact of climate on society. Model testing using sensitivity analysis and validation techniques is illustrated with two models: (1) the YIELD model which simulates the impact of climate on crop yields of several major crops, and (2) the International Futures Simulation model which can be used to simulate the impact of crop yield changes on the world food system. The problems of linking such models to each other are also discussed.  相似文献   
37.
38.
Although microorganisms are certainly present in swamp and marsh peats, their geochemical role has not been demonstrated, in spite of their importance in determining the input to coalification processes. In order to obtain information on the gross level of microbial activity in the natural habitats, a broad-spectrum test for a type of enzyme important in the respiration of all organisms has been applied to cores of peat from a number of different environments in the Florida Everglades. In most cases, the respiratory activity in the upper layer is comparable to that in a fertile mineral soil, and this level of activity is found also at greater depths in several cores. In addition, some properties of the peat that tend to define their character as habitats for microorganisms were determined. pH values close to neutrality were observed at all sites. Chlorinity and total ionic strength naturally were high in the coastal swamps; seasonal variations in profiles in the brackish areas somewhat away from the coast suggested that some bulk flow of water through the peat into the porous limestone bedrock occurs in the rainy season. Eh profiles, regarded as empirical characterizations of environments, did differ considerably between saline and fresh water peats, though on a graphite indicator electrode were more positive than might have been expected in systems in which sulfate reduction was active. However, in these non-equilibrium systems, the potential recorded apparently depends on the nature of the electrode material used.  相似文献   
39.
Two Hercynian duplexes are developed in Viséan limestones in the Basse Normandie quarry. The lower duplex is completely exposed in a subvertical quarry wall; the partially exposed upper duplex lies immediately above the lower duplex. The duplexes are both located in the footwall of the Hydrequent thrust which emplaced Devonian clastic sediments above the Viséan limestones. The lower duplex exposes all the internal thrusts, a reference bed of chalky limestone, the roof and floor thrusts, and the duplex tip. The duplex has been graphically restored to its pre-deformation geometry by line-length and area balancing and its resultant geometry is close to the model of Boyer & Elliott. The lower duplex shortened by two different mechanisms, an initial phase of layer-parallel shortening which produced no cleavage, followed by thrust imbrication. The average contraction of the front portion of the duplex was ?49% (natural strain) of which ?27% is layer-parallel shortening and ?22% is thrust imbrication. However, locally the bulk shortening increases from zero at the duplex tip to over ?120% in a down-dip direction. The area balancing provides the most accurate estimates of bulk shortening; line-length balance calculations give minimum estimates only. An area balance on the whole of the lower duplex gives a bulk shortening of ?84%. An area balance of the upper duplex yields an average contraction of ?75% and the total contraction produced by both duplexes is ?92%.  相似文献   
40.
Although the physics of evaporation within the inner region of the boundary layer is believed to be well understood, observations of mass-energy exchange processes have been hindered by the limitations of point sensors. A combination of point sensors and active remote sensing, namely, water-Raman Lidar measurements, offers new opportunities to study relatively large areas at temporal and spatial scales previously unattainable. Results from experiments over uniform canopies both confirm some traditional theories and challenge some of the underlying assumptions concerning the homogeneity of the surface-atmosphere interface and the use of point sensors to characterize large areas.This work was performed under the auspices of the U.S. Department of Energy. The authors would like to thank F. Archuleta, J. Archuleta, F. Barnes, W. Clements, K. Muller and W. Porch of LANL, R. Whitis of USDA, R. Jackson and P. Pinter of USDA-WCL, and L. Balick of EG&G for their invaluable time and support.  相似文献   
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