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21.
The Arctic is a region of the world experiencing extremely rapid climatic and social change. Indigenous communities have faced similar challenges for millennia and have historically demonstrated remarkable resilience to socioecological perturbations. In contemporary contexts, however, it appears that the pace and extent of change is overwhelming the adaptive capacities of many indigenous communities. Scholars recently completed a survey of living conditions spanning the circumpolar Arctic to quantitatively document the impacts of social and ecological stress across regions. The database they created is called the Survey of Living Conditions in the Arctic or SLiCA. This article explores the utility of using this dataset to compare livelihood systems across three sub-regions of Alaska and four sub-regions within the Chukotka Autonomous Okrug of the Russian Federation. The results point out that livelihood systems in Chukotka have a substantially lower level of sustainability than in Northwest Alaska due to the high prevalence of vulnerable households.  相似文献   
22.
Adaptive capacity in a community context has so far mainly been studied in developing countries as well as indigenous communities in the industrialised world. This article adds to that literature through reviewing studies undertaken in the Nordic countries and Russia, highlighting the ways in which general determinants of adaptive capacity play out in Northern, industrialised contexts. The paper illustrates that the determinants of adaptive capacity in industrialised states exhibit systematic differences from mixed subsistence-cash based communities such as those found in Arctic Canada. We discuss in particular the importance of economic resources in a market-based system, technological competition, and infrastructure, in determining adaptive capacity of natural resource-dependent communities in the Nordic countries and Russia. The paper also illustrates differences in adaptive capacity within the case study region, including between peripheral and central locations with regard to economic resources and diversification possibilities, and between Nordic and Russian cases with regard to infrastructure and technology access. The findings indicate that understanding of determinants of adaptive capacity in resource-dependent communities would benefit from both further contextualisation and broad comparison, across different types of political and administrative systems.  相似文献   
23.
Managers of the nearly 0.5 million ha of public lands in North and South Dakota, USA rely heavily on manual measurements of canopy height in autumn to ensure conservation of grassland structure for wildlife and forage for livestock. However, more comprehensive assessment of vegetation structure could be achieved for mixed-grass prairie by integrating field survey, topographic position (summit, mid and toeslope) and spectral reflectance data. Thus, we examined the variation of mixed-grass prairie structural attributes (canopy leaf area, standing crop mass, canopy height, nitrogen, and water content) and spectral vegetation indices (VIs) with variation in topographic position at the Grand River National Grassland (GRNG), South Dakota. We conducted the study on a 36,000-ha herbaceous area within the GRNG, where randomly selected plots (1?km2 in size) were geolocated and included summit, mid and toeslope positions. We tested for effects of topographic position on measured vegetation attributes and VIs calculated from Landsat TM and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data collected in July 2010. Leaf area, standing crop mass, canopy height, nitrogen, and water content were lower at summits than at toeslopes. The simple ratio of Landsat Band 7/Band 1 (SR71) was the VI most highly correlated with canopy standing crop and height at plot and landscape scales. Results suggest field and remote sensing-based grassland assessment techniques could more comprehensively target low structure areas at minimal expense by layering modeled imagery over a landscape stratified into topographic position groups.  相似文献   
24.
The toxicity of oil sands process-affected water (OSPW) has regularly been attributed to naphthenic acids, which exist in complex mixtures. If on remediation treatment (e.g., ozonation) or on entering the environment, the mixtures of these acids all behave in the same way, then they can be studied as a whole. If, however, some acids are resistant to change, whilst others are not, or are less resistant, it is important to establish which sub-classes of acids are the most toxic.  相似文献   
25.
26.
Environmental Science and Pollution Research - The objective of this study was to monitor a newly constructed wetland (CW) in north Wales, UK, to assess whether it contributes to an improvement in...  相似文献   
27.
Summary The US federal government has deliberately shifted a great deal of responsibility for protecting public health and the environment to the 50 US States. Some States are able and willing to assume control, but many others cannot or will not. It is argued that the American federal government should be prepared to intervene in those States that do not place health and environment on their agenda.Dr. Michael Greenberg is Professor of the School of Urban and Regional Policy at Rutgers as well as being an Advisory Board member to this journal. Prof. Frank Popper chairs the Department of Urban Studies and Community Health at Rutgers University. He has written extensively about land use issues and the American Great Plains. Bernadette West is a doctoral candidate in the Department of Urban Planning and Policy Development, Rutgers University. Her thesis concerns scientific and political issues in developing cancer research centers.  相似文献   
28.
Research examining the effects of unemployment among white collar workers has produced patterns of findings different to those for lower socio-economic groups. The present longitudinal questionnaire study examines the psychological impact of managerial job moves which are downward in status, and considers the effects of periods of unemployment between job changes. The results indicate that among managers the negative impact of downward status moves on psychological adjustment is greater than that of temporary role loss. These effects are associated with decrements in preceived growth and development opportunities at work. The relationship between work and non-work life for our understanding of psychological adjustment is considered.  相似文献   
29.
The mechanism of silicification from which the intricate cell walls of diatoms emerge, as well as the stereochemical relationship between the wall's organic casing and the siliceous materials within, continue to elude current technology. The present study further develops Hecky et al.'s standing model of the organicinorganic interface with semi-empirical computer simulations of a biosilicification pathway. Polycondensation reactions between silicic acid molecules and a hydroxyl-rich -sheet protein template results in a stereochemically-compatible chemisorbed tetrasiloxane ring. The 24-stage reaction pathway has an activation barrier of +15.4 kcal mol-1 and results in a net stabilization of-28.0 kcal mol-1. Spatial matching and favorable thermodynamics support the theory of protein-mediated biomineralization of the diatom.  相似文献   
30.
The Manila clam Ruditapes philippinarum was introduced to Poole Harbour (lat 50°N) on the south coast of England in 1988 as a novel species for aquaculture. Contrary to expectations, this species naturalised. We report on individual growth patterns, recruitment, mortality and production within this population. On the intertidal mudflats the abundance of clams (>5 mm in length) varied seasonally between 18 and 56 individuals m−2. There appear to be two recruitment events per year and there were 6 year classes in the population. A mid-summer decline in abundance was partly due to increased mortality but probably also a result of down-shore migration in response to high water temperatures and the development of anoxic conditions. A winter fishery removes c 75% of clams of fishable size (maximum shell length ≥40 mm) and c 20% of the annual production. The fishery depresses the maximum age and size attained by the clams but appears to be sustainable. Clam mortality due to factors other than fishing is highest in late-winter to early spring. The growth of the clams is intermediate in comparison with many published studies but remarkably good given their intertidal position. As on the coasts of the Adriatic Sea, where the clam is also non-native, the Manila clam has thrived in a shallow, eutrophic, lagoon-like system on the English coast. While the Poole Harbour population is currently Europe’s most northerly reported self-sustaining, naturalised population, given forecasts of increasing air and sea temperatures it might be expected that this species will eventually spread to more sites around the coasts of Northern Europe with associated economic and ecological consequences.  相似文献   
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