Worlds in one city     

Sarah Holloway  Phil Hubbard  Heike Jöns  Liz Mavroudi  Pat Noxolo 《Area》2008,40(3):412-413

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Navy sonar and cetaceans: just how much does the gun need to smoke before we act?     

Parsons EC  Dolman SJ  Wright AJ  Rose NA  Burns WC 《Marine pollution bulletin》2008,56(7):1248-1257

Cetacean mass stranding events associated with naval mid-frequency sonar use have raised considerable conservation concerns. These strandings have mostly involved beaked whales, with common pathologies, including "bubble lesions" similar to decompression sickness symptoms and acoustic traumas. However, other cetacean species have also stranded coincident with naval exercises. Possible mechanisms for the strandings include a behavioral response that causes deep divers to alter their diving behavior, which then results in decompression sickness-like impacts. Current mitigation measures during military exercises are focused on preventing auditory damage (hearing loss), but there are significant flaws with this approach. Behavioral responses, which occur at lower sound levels than those that cause hearing loss, may be more critical. Thus, mitigation measures should be revised. A growing number of international bodies recognize this issue and have urged increasing scrutiny of sound-producing activities, but many national jurisdictions have resisted calls for increased protection.  相似文献   

Doing interdisciplinarity: motivation and collaboration in research for sustainable agriculture in the UK     

Frances Harris  Fergus Lyon  Sarah Clarke 《Area》2009,41(4):374-384

This paper studies knowledge production in complex, collaborative research projects that brought together academics from different disciplines, research users and agricultural businesses. It takes a comparative approach, studying the interactions within interdisciplinary research teams from ten case studies, considering the process of collaboration from initial idea through to publication. The research developed a typology of participants in these projects, and identified the motivations and challenges of each. Our results analyse the process of research teams coming together and the relationships that are built up during the research. A particular challenge identified was the building of cooperation and trust. This issue is explored alongside issues of communication, methodology, data analysis and the process of drawing and publicising conclusions.  相似文献   

'Private life' and 'work life': difficulties and dilemmas when making and maintaining friendships with ethnographic participants     

Sarah Marie Hall 《Area》2009,41(3):263-272

This paper addresses the difficulties and dilemmas that may occur when friendships are formed with participants during an ethnographic research project. The ongoing, reciprocal relationships developed with participants are considered essential in the data collection of ethnography, as an avenue through which research can be carried out. However, while friendships in the field may open new doors to research, they can also create new (ethical) challenges. This paper revisits these issues, alongside research ethics guidelines, using three different scenarios: the negotiation of methods of contact, the maintenance of contact with participants and the sharing of research diaries with participants. From these discussions, two issues arise that may have implications for future ethnographic research: the obstacle of social networking websites and the negotiation of appropriate research ethics when participants become our friends.  相似文献   

Demographic and environmental conditions are uncoupled in the social–ecological system of the Pribilof Islands     

Henry P. Huntington  Sarah A. Kruse  & Astrid J. Scholz 《Polar research》2009,28(1):119-128

Since the end of the commercial fur seal hunt in 1984, the economy of the Pribilof Islands, Alaska, has lacked a stable, lasting basis. As a contribution to the effort to understand and promote the effective management of the Pribilof Islands as a social–ecological system, we examined current and recent conditions on the islands to assess local perceptions of, and prospects for, economic, social and environmental well-being. We found few correlations between environmental conditions and socio-economic indicators. The lack of apparent connection between population levels and economic or environmental stimuli is likely attributable to one or more of several factors: (a) modest economic dependence on the environment; (b) predominance of other economic inputs to the economies of the islands; (c) islanders basing residence choices largely on non-economic factors; and (d) the islanders' tolerance for economic fluctuations and uncertainty. These results suggest economic analysis alone is insufficient to explain the dynamics of this social–ecological system, contrary to many other case studies and an expectation of tight coupling and clear connections between society and ecology in the Pribilofs.  相似文献   

International perspectives on rural homelessness - by P. Milbourne and P. Cloke     

Sarah Johnsen 《New Zealand geographer》2009,65(1):83-84

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A critique of the UK’s JNCC seismic survey guidelines for minimising acoustic disturbance to marine mammals: Best practise?     

E.C.M. Parsons  Sarah J. Dolman  Michael Jasny  Mark P. Simmonds 《Marine pollution bulletin》2009,58(5):643-651

The United Kingdom’s statutory conservation agency, the Joint Nature Conservation Committee (JNCC), developed guidelines in 1995 to minimise acoustic disturbance of marine mammals by oil and gas industry seismic surveys. These were the first national guidelines to be developed and have subsequently become the standard, or basis, of international mitigation measures for noise pollution during seismic surveys. However, relatively few aspects of these measures have a firm scientific basis or proven efficacy. Existing guidelines do not offer adequate protection to marine mammals, given the complex propagation of airgun pulses; the difficulty of monitoring in particular the smaller, cryptic, and/or deep-diving species, such as beaked whales and porpoises; limitations in monitoring requirements; lack of baseline data; and other biological and acoustical complications or unknowns. Current guidelines offer a ‘common sense’ approach to noise mitigation, but in light of recent research and ongoing concerns, they should be updated, with broader measures needed to ensure adequate species protection and to address data gaps.  相似文献   

Influence of rural land use on streamwater nutrients and their ecological significance   总被引：1，自引：0，他引：1  

Helen P. Jarvie  Paul J.A. Withers  Robin Hodgkinson  Adam Bates  Margaret Neal  Heather D. Wickham  Sarah A. Harman  Linda Armstrong 《Journal of Hydrology》2008,350(3-4):166-186

Concentrations and loads of N and P fractions were examined for lowland rivers, the Wye and Avon, draining a range of representative agricultural land-use types in two major UK river basins. Data collected over a 2-year period demonstrated important diffuse agricultural source contributions to N and P loads in these rivers. Ground water provided a major source of total dissolved nitrogen (TDN) loads, whereas near-surface sources provided a major contribution to total phosphorus (TP) loads. In terms of aquatic ecology, concentrations of nutrients, at times of eutrophication risk (spring and summer low flows) were of key environmental and management significance. Agricultural diffuse sources provided the major source of long-term P loads across the two basins. However, the results demonstrated the dominance of point-source contributions to TP and SRP concentrations at times of ecological risk. Point sources typically ‘tip the balance’ of dissolved inorganic P (soluble reactive P, SRP) above the 100 μg l⁻¹ guideline value indicative of eutrophication risk. The significance of point sources for TP and SRP concentrations was shown by (a) the strong correlations between TP, SRP and B concentrations, using B as a tracer of sewage effluent, (b) the dominant contribution of SRP to TP concentrations and (c) the predominant pattern of dilution of SRP and B with flow. The clean Chalk streams draining low intensity grassland in areas of the Avon with sparse human settlement were oligotrophic and P limited with low SRP concentrations under spring and summer baseflows attributable to groundwater sources. The data provide important insights into the ecological functioning of different lowland stream systems. There was evidence of greater SRP losses and N-limitation in a stream which drains a pond system, demonstrating the importance of longer water residence times for biological nutrient uptake.  相似文献   

Bulk density of ordinary chondrite meteorites and implications for asteroidal internal structure     

Sarah L. WILKISON  Mark S. ROBINSON 《Meteoritics & planetary science》2000,35(6):1203-1213

Abstract— The bulk densities of 82 samples of 72 ordinary chondrites (OCs) were measured to an accuracy of ～1% using a modified Archimedian method. We found the average bulk density to be 3.44 ± 0.19 g/cm³ for the H group, 3.40 ± 0.15 g/cm³ for the L group, and 3.29 ± 0.17 g/cm³ for the LL group (± represent 1σ). Bulk density measurements of 11 pieces of one fall, Pultusk (H group), were also found to vary considerably (3.31 to 3.63 g/cm³). To investigate controls on bulk density within the OCs, we compared density with bulk chemical composition (the ratio of Fe metal to total Fe; the ratio of total Fe to SiO₂; the ratio of FeO to total Fe and MgO). Within each OC group, bulk chemical composition is nearly invariant whereas bulk density varies from about 3.0 to 3.8 g/cm³. Slight but systematic differences in average density between the H, L, and LL groups presumably relate to differences in metallic Fe abundance. However, considerable overlap between OC groups and the wide range of bulk densities within each group suggest differences in porosity dominantly control variations of density within the OC subgroups.  相似文献   

A new approach for the determination of the drag coefficient from the upper ocean response to a tropical cyclone: a feasibility study     

Sarah E. Zedler  Guido Kanschat  Robert Korty  Ibrahim Hoteit 《Journal of Oceanography》2012,68(2):227-241

We seek to determine if a small number of measurements of upper ocean temperature and currents can be used to make estimates of the drag coefficient that have a smaller range of uncertainty than previously found. We adopt a numerical approach using forward models of the ocean’s response to a tropical cyclone, whereby the probability density function of drag coefficient values as a function of wind speed that results from adding realistic levels of noise to the simulated ocean response variables is sought. Allowing the drag coefficient two parameters of freedom, namely the values at 35 and at 45 m/s, we found that the uncertainty in the optimal value is about 20% for levels of instrument noise up to 1 K for a misfit function based on temperature, or 1.0 m/s for a misfit function based on 15 m velocity components. This is within tolerable limits considering the spread of measurement-based drag coefficient estimates. The results are robust for several different instrument arrays; the noise levels do not decrease by much for arrays with more than 40 sensors when the sensor positions are random. Our results suggest that for an ideal case, having a small number of sensors (20–40) in a data assimilation problem would provide sufficient accuracy in the estimated drag coefficient.  相似文献