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531.
On the Role of Spatial,Temporal, and Climatic Forces on Stream Sediment Loading from Rural and Urban Ecosystems 下载免费PDF全文
Audrey L. Squires Jan Boll Erin S. Brooks 《Journal of the American Water Resources Association》2017,53(5):1195-1211
In this study, we characterize the greatest sediment loading events by their sediment delivery behavior; dominant climate, watershed, and antecedent conditions; and their seasonal distribution for rural and urban land uses. The study area is Paradise Creek Watershed, a mixed land use watershed in northern Idaho dominated by saturation excess processes in the upstream rural area and infiltration excess in the downstream urban area. We analyzed 12 years of continuous streamflow, precipitation, and watershed data at two monitoring stations. We identified 137 sediment loading events in the upstream rural section of the watershed and 191 events in the downstream urban section. During the majority of these events conditions were transport limited and the sediment flush occurred early in the event, generally in the first 20% of elapsed event time. Statistical analysis including two dozen explanatory variables showed peak discharge, event duration, and antecedent baseflow explained most of the variation in event sediment load at both stations and for the watershed as a whole (R2 = 0.73‐0.78). In the rural area, saturated soils combined with spring snowmelt in March led to the greatest loading events. The urban area load contribution peaked in January, which could be a re‐suspension of streambed sediments from the previous water year. Throughout the study period, one event contributed, on average, 33% of the annual sediment load but only accounted for 2% of the time in a year. 相似文献
532.
迄今,西方社会早已迈过严重污染阶段(如雾霾),环境责任承担(CER)几乎成为跨国企业的标准范式,全面回顾国外CER研究对深处环境危机中的中国来说具有很强的现实意义。本文回顾了国外学术界从商业伦理、利益相关者管理、战略管理、环境行为及环境绩效视角的CER研究,归纳总结了CER概念主张及维度测量。研究发现,制度环境、市场状况、产业现状、利益相关者等是促成企业CER行动的外部因素,而企业规模、发展战略、治理结构以及技术条件等是制约CER行动的内部因素,内外多种因素的整合作用决定企业CER行为。此外,研究还发现,CER可以提升资源利用效率、降低成本费用与提升技术能力等,还能够帮助企业获得良好声誉和改善品牌形象,在一定条件下也可帮助企业建构可持续竞争优势,甚至对企业的财务绩效产生积极影响。最后,本文展望了CER研究的全球本土化、创新性、实务性以及中小企业化等发展方向,并分析探讨了国外CER研究对中国本土研究和CER实务的启示。 相似文献
533.
Development based climate change adaptation and mitigation—conceptual issues and lessons learned in studies in developing countries 总被引:3,自引:0,他引:3
Kirsten Halsnæs Jan Verhagen 《Mitigation and Adaptation Strategies for Global Change》2007,12(5):665-684
This paper discusses the conceptual basis for linking development policies and climate change adaptation and mitigation and suggests an analytical approach that can be applied to studies in developing countries. The approach is centred on a broad set of policy evaluation criteria that merge traditional economic and sectoral goals and broader social issues related to health and income distribution. The approach is inspired by institutional economics and development paradigms that emphasise human wellbeing, resource access, empowerment, and the arrived freedoms. It is outlined how indicators of wellbeing can be used to assess policies that integrate development and climate change policy objectives, and this approach is discussed in comparison with other work that rather have been inspired by sustainable development aspects of manmade, natural, and social capital. The experiences and results from case studies of development and climate that have done a first attempt to use human wellbeing indicators are reported and discussed. The studies include work from India, China, South Africa, Brazil, Bangladesh, and Senegal. A number of policy examples in the energy-, food-, and water sectors in these studies have shown up to demonstrate numerous linkages between development policies and climate change. Various analytical tools have been used in the studies including quantitative and qualitative scenario work as well as detailed micro-based analysis. The methodological conclusion that can be drawn from these studies, is that it is possible to apply wellbeing indicators to the more detailed policy assessment, but a link to more general national and regional scenario work is not yet established. 相似文献
534.
Diana W. Bianchi Tim Van Mieghem Lisa G. Shaffer Brigitte H. W. Faas Lyn S. Chitty Alessandro Ghidini Jan Deprest 《黑龙江环境通报》2014,34(1):1-5
本文提出怎样理解产学研相结合的问题,并从产学研不同层面进行分析,提出以市场为目标、以制度为保证实现产学研有效结合的思路。 相似文献
535.
Jan A. Deprest Alan W. Flake Eduard Gratacos Yves Ville Kurt Hecher Kypros Nicolaides Mark P. Johnson François I. Luks N. Scott Adzick Michael R. Harrison 《黑龙江环境通报》2010,30(7):653-667
Fetal diagnosis prompts the question for fetal therapy in highly selected cases. Some conditions are suitable for in utero surgical intervention. This paper reviews historically important steps in the development of fetal surgery. The first invasive fetal intervention in 1963 was an intra-uterine blood transfusion. It took another 20 years to understand the pathophysiology of other candidate fetal conditions and to develop safe anaesthetic and surgical techniques before the team at the University of California at San Francisco performed its first urinary diversion through hysterotomy. This procedure would be abandoned as renal and pulmonary function could be just as effectively salvaged by ultrasound-guided insertion of a bladder shunt. Fetoscopy is another method for direct access to the feto-placental unit. It was historically used for fetal visualisation to guide biopsies or for vascular access but was also abandoned following the introduction of high-resolution ultrasound. Miniaturisation revived fetoscopy in the 1990s, since when it has been successfully used to operate on the placenta and umbilical cord. Today, it is also used in fetuses with congenital diaphragmatic hernia (CDH), in whom lung growth is triggered by percutaneous tracheal occlusion. It can also be used to diagnose and treat urinary obstruction. Many fetal interventions remain investigational but for a number of conditions randomised trials have established the role of in utero surgery, making fetal surgery a clinical reality in a number of fetal therapy programmes. The safety of fetal surgery is such that even non-lethal conditions, such as myelomeningocoele repair, are at this moment considered a potential indication. This, as well as fetal intervention for CDH, is currently being investigated in randomised trials. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
536.
The amniotic fluid is a clinically accessible source of mesenchymal stem cells (AF-MSC) during gestation, which enables autologous cellular therapy for perinatal disorders. The origin of AF-MSC remains elusive: renal and neuronal progenitors have been isolated from the AF-MSC pool, yet no cells with pulmonary characteristics. We analyzed gene expression of pulmonary and renal markers of 212 clonal lines of AF-MSC isolated from amniocentesis samples. AF-MSC were cultured on dishes coated with extracellular matrix (ECM) proteins from decellularized fetal rabbit lungs. In vivo differentiation potential of AF-MSC that expressed markers suggestive of lung fate was tested by renal subcapsular injections in immunodeficient mice. Of all the isolated AF-MSC lines, 26% were positive for lung endodermal markers FOXA2 and NKX2.1 and lacked expression of renal markers (KSP). This AF-MSC subpopulation expressed other lung-specific factors, including IRX1, P63, FOXP2, LGR6, SFTC, and PDPN. Pulmonary marker expression decreased over passages when AF-MSC were cultured under conventional conditions, yet remained more stable when culturing the cells on lung ECM-coated dishes. Renal subcapsular injection of AF-MSC expressing lung-specific markers resulted in engrafted cells that were SPTB positive. These data suggest that FOXA2+/NKX2.1+/KSP- AF-MSC lines have lung characteristics which are supported by culture on lung ECM-coated dishes. 相似文献
537.
538.
Schipper AM Wijnhoven S Leuven RS Ragas AM Hendriks AJ 《Environmental pollution (Barking, Essex : 1987)》2008,151(1):17-26
Soil metal concentrations, inundation characteristics and abundances of 14 arthropod taxa were investigated in a moderately contaminated lowland floodplain along the Rhine River and compared to the hinterland. Internal metal concentrations were determined for the orders of Coleoptera (beetles) and Araneida (spiders) and were related to soil concentrations. The floodplain was characterized by larger arthropod abundance than the hinterland, in spite of recurrent inundations and higher soil metal concentrations. Most arthropod taxa showed increasing abundance with decreasing distance to the river channel and increasing average inundation duration. For Cd, Cu, Pb and Zn, significant relations were found between arthropod concentrations and concentrations in soil. Significant relations were few but positive, indicating that increasing soil concentrations result in increasing body burdens in arthropods. For arthropod-eating vertebrates, these results might imply that larger prey availability in the floodplain coincides with higher metal concentrations in prey, possibly leading to increased exposure to metal contamination. 相似文献
539.
540.
Rodríguez I Gumbert A Hempel de Ibarra N Kunze J Giurfa M 《Die Naturwissenschaften》2004,91(8):374-377
Bilateral symmetry has been considered as an indicator of phenotypic and genotypic quality supporting innate preferences for highly symmetric partners. Insect pollinators preferentially visit flowers of a particular symmetry type, thus leading to the suggestion that they have innate preferences for symmetrical flowers or flower models. Here we show that flower-naïve bumblebees (Bombus terrestris), with no experience of symmetric or asymmetric patterns and whose visual experience was accurately controlled, have innate preferences for bilateral symmetry. The presence of color cues did not influence the bees original preference. Our results thus show that bilateral symmetry is innately preferred in the context of food search, a fact that supports the selection of symmetry in flower displays. Furthermore, such innate preferences indicate that the nervous system of naïve animals may be primed to respond to relevant sensory cues in the environment. 相似文献