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51.
Edmunds, Jake, Glenn Tootle, Greg Kerr, Ramesh Sivanpillai, and Larry Pochop, 2011. Glacier Variability (1967‐2006) in the Teton Range, Wyoming, United States. Journal of the American Water Resources Association (JAWRA) 48(1): 187‐196. DOI: 10.1111/j.1752‐1688.2011.00607.x Abstract: Glacier area and volume changes were quantified through the use of historical aerial photographs in Wyoming’s Teton Range. Glacier area changes in the Teton Range were estimated for three glaciers using unrectified aerial photography from 1967 to 2006. The total surface area of the three glaciers was 0.53 km2 in 1967 and 0.40 km2 in 2006, a decrease of 25% during the 39‐year period. The smallest glacier, Teepe, experienced the greatest area loss (60 ± 3%), whereas the largest glacier, Teton Glacier, lost 17 ± 3% of the 1967 area. For the current research, aerial photography from 1967 to 2002 was used to estimate glacier volume loss using stereoscopy techniques. The aerial photographs provide a finer resolution when compared with other datasets including satellite imagery (e.g., Landsat). Volume loss for the three glaciers was estimated to be 3.20 ± 0.46 million cubic meters over the period of 1967 to 2002. In assessing the primary climatic driver of the glacier ice loss, observed summer (June, July, and August) temperature data showed a statistically significant increase in temperatures when comparing the period of study (1968 to 2006) with historical temperatures from 1911 to 1967. When comparing spring (April 1st Snow Water Equivalent) snowpack for the period of study with historical records beginning in 1931, a significant difference in snowpack was not observed.  相似文献   
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In a chemical sense, the positive muon is a light proton. It is obtained at the ports of accelerators in beams with a spin polarization of 100%, which makes it a highly sensitive probe of matter. The muonium atom is a light hydrogen isotope, nine times lighter than H, with a muon as its nucleus. It reacts the same way as H, and by addition to double bonds it is implemented in free radicals in which the muon serves as a fully polarized spin label. It is reviewed here how the muon can be used to obtain information about muonium and radical reaction rates, radical structure, dynamics, and local environments. It can even tell us what a fragrance molecule does in a shampoo.  相似文献   
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Groundwater pumping depletes streamflow, which can have significant ecological impacts depending on the magnitude of depletion relative to environmental flow needs. Streamflow depletion estimates from groundwater pumping have been quantified using both analytical and numerical methods, but are not routinely compared to environmental flow needs or used in practical water management tools. Decision support tools that incorporate groundwater dynamics are becoming increasingly necessary for water managers as groundwater regulations become more important in environmental policy, particularly concerning the preservation of environmental flow needs. We develop and apply methods for a web‐based decision support tool for conjunctive groundwater and surface water management, demonstrated using a case study watershed in British Columbia, Canada. Open‐source data are analyzed with a combination of spatial algorithms and previously developed analytical models, such that the tool can be applied to other regions. Streamflow depletion estimates are calculated in four regions in the largely undeveloped Bulkley Valley, British Columbia. Our transparent methodology has geographic and data input flexibility which is a significant improvement on currently existing water management tool methods.  相似文献   
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As part of a harmonised assessment of urban soils (), we investigated the variability of metal content in soils from Aveiro (Portugal) and Glasgow (UK). Samples were collected from parks and other public open spaces in each city. Metal content (Al, Ca, Cr, Cu, Fe, Mn, Ni, Pb and Zn) and basic soil parameters (texture, CEC, pH, organic matter) were determined and data investigated using principal component analysis (PCA). The two cities differ in absolute levels of metal content reflecting industrial and historical development. Factors identified by PCA included anthropogenic (Cu, Pb, Zn), soil properties and geology, which explain variability when data were assessed based on metal content, soil properties and land use. This study highlights the contribution from geological background even in strongly urbanised environments.  相似文献   
56.
Nitrogen excretion and ammonia emissions from pigs fed modified diets   总被引:3,自引:0,他引:3  
Two swine feeding trials were conducted (initial body weight = 47 +/- 2 and 41 +/- 3 kg for Trials 1 and 2, respectively) to evaluate reduced crude protein (CP) and yucca (Yucca schidigera Roezl ex Ortgies) extract-supplemented diets on NH3 emissions. In Trial 1, nine pigs were offered a corn-soybean meal diet (C, 174 g kg(-1) CP), a Lys-supplemented diet (L, 170 g kg(-1) CP), or a 145 g kg(-1) CP diet supplemented with Lys, Met, Thr, and Trp (LMTT). In Trial 2, nine pigs were fed diet L supplemented with 0, 62.5, or 125 mg of yucca extract per kg diet. Each feeding period consisted of a 4-d dietary adjustment followed by 72 h of continuous NH3 measurement. Urine and fecal samples were collected each period. Feeding the LMTT diet reduced (P < 0.05) average daily gain (ADG) and feed efficiency (G:F) compared to diet L. Fecal N concentration decreased with a reduction in dietary CP, but urinary ammonium increased from pigs fed diet LMTT (2.0 g kg(-1), wet basis) compared to those fed diet C (1.1 g kg(-1)) or L (1.0 g kg(-1)). When pigs were fed reduced CP diets NH3 emission rates decreased (2.46, 2.16, and 1.05 mg min(-1) for diets C, L, and LMTT). Yucca had no effect on feed intake, ADG, or G:F. Ammonium and N concentrations of manure and NH3 emission rates did not differ with yucca content. Caution must be executed to maintain animal performance when strategies are implemented to reduce NH3 emissions.  相似文献   
57.
Land-use patterns are influenced by both top-down and bottom-up (local) factors, with their interactions varying in both space and time. This provides a major challenge to decision-making for sustainable multifunctional landscapes. A cross-scale scenario structure has been developed to integrate top-down and bottom-up context based upon the familiar IPCC Special Report on Emission Scenarios framework. Qualitative scenario storylines are converted into multiple quantified simulations of regional land-use change using a series of rules, with information translated across scales using a hierarchical land-use classification. Land-use parcels (fields) are used as key landscape reference units representing the local dimension of regional changes. Biophysical limitations on land use are represented through land capability classes (climate, soils and topography). Socio-economic factors are characterised in reference to global drivers, policy targets or local preferences. A flexible stochastic software tool (LandSFACTS) ensures spatiotemporal coherence of land-use allocation simulations consistent with scenario storylines. Scenario development is designed to be interactive, bridging ‘problem-focussed’ and ‘actor-focussed’ approaches. A case study is presented from NE Scotland, where plans to enhance multifunctionality through new woodland are evaluated against drivers of globalisation and climate change. Competing priorities, such as food security, mean that in some scenarios, a policy objective for woodland expansion to occur on farmland cannot be met. Woodland expansion would then have to occur on uncultivated upland areas. Scenario analysis has highlighted specific sensitivity to change in ‘marginal’ agricultural areas, with the varying influence of different top-down or bottom-up factors leading to divergent potential outcomes.  相似文献   
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Environmental change requires adaptive responses that are innovative, forward-looking and anticipatory, in order to meet goals for sustainability in socio-ecological systems. This implies transformative shifts in understanding as conceptualised by the idea of ‘double’- or ‘triple-loop learning’. Achieving this can be difficult as communities often rely on shorter-term coping mechanisms that purport to maintain the status quo. The use of participatory scenario planning to stimulate forward-looking social learning for adaptation was investigated through three contrasting community case studies on natural resource management in Latin America (in Mexico, Argentina and Colombia). Exploratory scenario narratives that synthesised local knowledge and future perceptions were used iteratively to define response options considered robust across multiple futures. Despite its intensive format, participants in each case agreed that scenario planning enabled a more systematic appraisal of the future. Scenarios facilitated innovation by providing scope to propose new types of responses and associated actions. Differences in local context meant that learning about future change developed in diverse ways, showing a need for a reflexive process. Reframing of key issues characteristic of double-loop learning did occur, albeit through different forms of interaction in each location. However, a shift towards transformative actions characteristic of triple-loop learning was less evident. Achieving this would appear to require ongoing use of scenarios to challenge social norms in light of changing drivers. Use of learning loops as a diagnostic to evaluate adaptive responses provided a useful reference framework although in practice both innovation and consolidative approaches can develop concurrently for responses to different issues.  相似文献   
60.
Total concentrations of arsenic in surface (0–15cm) garden soils in the historical mining area of Hayle-Camborne-Godolphin, Cornwall, England are large and range widely (144–892 g/g). Amounts of water soluble and acid-fluoride extractable soil arsenic are significantly correlated with total content.Examination of 6 salad and vegetable crops grown in 32 gardens has shown arsenic concentrations in the edible tissues to be only slightly elevated. There were strong correlations between arsenic in beetroot, lettuce, onion and peas and soil arsenic (total, water soluble and acid extractable). Regression equations have been calculated. Ridge regression analysis applied to test the importance of other soil variables has shown both iron and phosphorus to influence the uptake of arsenic.Arsenic in all the vegetables sampled was below the statutory limit in the U.K. of 1 mg/kg fresh weight. Implications for health should be assessed in relation to other exposure routesvia water, air and directly ingested dust and soil.  相似文献   
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