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671.
Michael M. Pollock Timothy J. Beechie 《Journal of the American Water Resources Association》2014,50(3):543-559
Intact riparian ecosystems are rich in biological diversity, but throughout the world, many have been degraded. Biodiversity declines, particularly of vertebrates, have led to experimental efforts to restore riparian forests by thinning young stands to accelerate creation of large diameter live trees. However, many vertebrates depend on large diameter deadwood that is standing as snags or fallen to the forest floor or fallen into streams. Therefore, we reviewed the sizes of deadwood and live trees used by different vertebrate species to understand which species are likely to benefit from different thinning treatments. We then examined how riparian thinning affects the long‐term development of both large diameter live trees and deadwood. To this end, we used a forest growth model to examine how different forest thinning intensities might affect the long‐term production and abundance of live trees and deadwood. Our results suggest that there are long‐term habitat tradeoffs associated with different thinning intensities. Species that utilize large diameter live trees will benefit most from heavy thinning, whereas species that utilize large diameter deadwood will benefit most from light or no thinning. Because far more vertebrate species utilize large deadwood rather than large live trees, allowing riparian forests to naturally develop may result in the most rapid and sustained development of structural features important to most terrestrial and aquatic vertebrates. 相似文献
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本文以标准GB/T 29309-2012为基础,以某款开关电源为例,对HALT试验设备、工作极限与破坏极限、试验步骤及设备运行中注意点等方面展开介绍,为电子产品可靠性测试提供相关探讨。 相似文献
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Abstract Earlier papers indicated that the first incident of green discoloration in oysters (Crassostrea gigas) and the mass mortality observed in 1986 along the Taiwan Erhjin Chi coastal area were caused by the higher contents of total copper and copper species (mainly bioavailable and free ion) in sea water. the copper in sea water would be sorbed by suspended matter and transferred to sediments, and the copper in the sediments would also be desorbed to sea water. Processes of copper adsorption and desorption are the major factors influencing the contents of total copper and copper species in sea water and sediments. in this study, the Erhjin Chi sediments were mixed with sea water by a shaker technique. When the mixture was shaken for one hour, analogous to tidal mixing in estuaries, only copper desorption from sediments was observed. If the shaking time is increased for more than 3 hours, the copper released from the sediments was resorbed to the remaining solid phases. the higher the contents of mud (91.71%) and total copper (701 mg kg?1) in sediments, the higher the copper desorption rate (1.86 ppm hr?1) and copper adsorption rate (0.50 ppm hr?1) were observed. in sediments containing lower mud (0.80%) and lower copper (43.5 mg kg?1), the copper desorption and adsorption rates were 0.83 ppm hr?1 and 0.22 ppm hr?1, respectively. the interactions among the total copper and copper species in sea water and sediments, chemical and ecological parameters, and copper bioaccumulation in oysters in the Erhjin Chi estuarine and coastal area are also discussed. 相似文献
675.
This article examines the framing of environmental risks and natural disasters in factual entertainment television programs of the early 2000s, a hybrid form combining techniques from documentary with techniques such as dramatic reconstructions and computer-generated imagery from entertainment genres. Using qualitative frame analysis, it examines a range of factual entertainment television programs' framing of environmental risk and natural disasters in terms of their attitudes, representation of human participants and visual composition. The article considers the similarities and differences in the framing of natural disasters as factual entertainment compared to the framing of natural disasters in news, documentary and fiction film. It argues that such programs offer representational frames both consonant with and distinct from other media and concludes that they problematically offer a predominantly fatalistic response to environmental risk, constructing natural disasters as voyeuristic spectacles for vicarious entertainment. 相似文献
676.
Paul E. Spector 《组织行为杂志》2012,33(2):151-152
This paper introduces a Journal of Organizational Behavior point/counterpoint exchange (this issue) that focuses on the appropriate level of aggregation primarily in the assessment of personality in general and core self‐evaluations (CSE) in particular. Gilad Chen reviews arguments for and against the higher‐order construct of CSE, offering a number of recommendations for strengthening it. Timothy Judge and John Kammeyer‐Mueller offer a defense of CSE, and then extend the discussion to the measurement of other constructs beyond the personality domain. Together these two papers provide important insights about the appropriate level of aggregation of individual measures, and situations in which higher‐order versus lower‐order measures might be preferred. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
677.
Yuan Ma Shan Zhai Shi Yun Mao Shi Lei Sun Ying Wang Zhong Hua Liu 《Journal of environmental science and health. Part. B》2013,48(9):661-670
A new imidacloprid (IMI) degrading bacterium Z-9 (deposited number CGMCC 6648) was isolated and identified as Pseudoxanthomonas indica by 16S rRNA gene analysis. Two metabolites were identified as olefin and 5-hydroxy IMI by liquid chromatography-mass spectrometry and nuclear magnetic resonance analysis. P. indica CGMCC 6648 degraded 70.1% of IMI (1.22 mmol L?1) and formed 0.93 mmol L?1 5-hydroxy IMI and 0.05 mmol L?1 olefin IMI in 6 days and in the presence of 100 mmol L?1 glucose. The half-life of IMI degradation was 3.6 days. P. indica CGMCC 6648 transforms IMI via a co-metabolism mechanism and different carbohydrates have significant effects on 5-hydroxy IMI formation, whereas different organic acids have substantial effects on olefin IMI production. Lactose is the best co-substrate for IMI degradation and 5-hydroxy IMI formation with 0.77 mmol L?1 degraded and 0.67 mmol L?1 formed in 48 h, respectively. Pyruvate is the best co-substrate for olefin IMI formation with 0.17 mmol L?1 produced in 96 h for all carbon sources tested. Pyruvate significantly stimulates the conversion of 5-hydroxy IMI to olefin IMI, whereas glucose slightly inhibits this reaction. P. indica CGMCC 6648 rapidly degrades IMI and forms olefin IMI, which may enhance its potential for biodegradation of IMI and increase its insecticidal activity, which can decrease the IMI dosage required. 相似文献
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