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321.
Scientists, resource managers, and decision makers increasingly use knowledge coproduction to guide the stewardship of future landscapes under climate change. This process was applied in the California Central Valley (USA) to solve complex conservation problems, where managed wetlands and croplands are flooded between fall and spring to support some of the largest concentrations of shorebirds and waterfowl in the world. We coproduced scenario narratives, spatially explicit flooded waterbird habitat models, data products, and new knowledge about climate adaptation potential. We documented our coproduction process, and using the coproduced models, we determined when and where management actions make a difference and when climate overrides these actions. The outcomes of this process provide lessons learned on how to cocreate usable information and how to increase climate adaptive capacity in a highly managed landscape. Actions to restore wetlands and prioritize their water supply created habitat outcomes resilient to climate change impacts particularly in March, when habitat was most limited; land protection combined with management can increase the ecosystem's resilience to climate change; and uptake and use of this information was influenced by the roles of different stakeholders, rapidly changing water policies, discrepancies in decision-making time frames, and immediate crises of extreme drought. Although a broad stakeholder group contributed knowledge to scenario narratives and model development, to coproduce usable information, data products were tailored to a small set of decision contexts, leading to fewer stakeholder participants over time. A boundary organization convened stakeholders across a large landscape, and early adopters helped build legitimacy. Yet, broadscale use of climate adaptation knowledge depends on state and local policies, engagement with decision makers that have legislative and budgetary authority, and the capacity to fit data products to specific decision needs.  相似文献   
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Leader–member exchange relationships have rarely been explored within the context of the work unit. Employing a sample of 285 employees of a southeastern county library system, the work unit contextual factors of work group size, work group cohesiveness, organizational climate, and leader power were examined for their relationship with LMX from the subordinate's perspective, using a within and between analysis (WABA) approach. All of the contextual variables except size were significantly related to LMX. The WABA and rWG analyses revealed that effects occurred at both within‐ and between‐group levels, indicating individual difference effects. Thus, practitioners should emphasize enhancements to group and organizational processes as well as contributions toward relationship building in LMX dyads. Future research should expand the network of contextual variables that may have potential relevance with LMX, since this study demonstrated that the work context in which the dyad resides contributes in part to the LMX phenomenon. Additional study of the work unit size and LMX relationship is also warranted, as the current research failed to replicate previous research with a predicted negative relationship. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   
323.
Chitosan fibers were prepared by wet spinning in three stages. Initially, a polymer solution of chitosan and polyvinyl alcohol (PVA) was solidified in a mixture of potassium hydroxide and ethanol. The polymers were then crosslinked with sodium tripolyphosphate (TPP) or glutaraldehyde, and finally dried in methanol or acetone. The effect of these conditions was evaluated based on scanning electron microscopy images, water-holding capacity, and swelling and mechanical properties. The miscibility of the mixture was evaluated using Fourier Transform Infrared spectroscopy and differential scanning calorimetry. The results obtained showed that chitosan fibers containing 45% (v/v) PVA and crosslinked using TPP have properties similar to those of commercial sutures prepared using other biomaterials.  相似文献   
324.
Vetter W  Turek C  Marsh G  Gaus C 《Chemosphere》2008,73(4):580-586
Marine mammals from Queensland, Australia, are bioaccumulating elevated concentrations of a range of polybrominated natural products. In this study, we detected three new polybrominated dimethoxybiphenyls (PBDMBs) in the blubber of selected marine mammal samples which were identified as 2,6'-dimethoxy-3,3',5-tribromobiphenyl (2,6'-diMeO-BB 36), 2,2'-dimethoxy-3,3'-dibromobiphenyl (2,2'-diMeO-BB 36), and 6,6'-dimethoxy-3,3'-dibromobiphenyl (6,6'-diMeO-BB 11). These three PBDMBs are structurally related to the known natural product 2,2'-dimethoxy-3,3',5,5'-tetrabromobiphenyl (2,2'-diMeO-BB 80). In the first part of this study, 2,2'-diMeO-BB 80 was photochemically debrominated under UV irradiation. This resulted in seven of eight possible mono- to triBDMBs as debromination products. In the second part of this study, the structure of all PBDMBs debromination products was investigated. This was supported by synthesis of two diBDMB and one triBDMB via bromination and subsequent methylation of 2,2'-biphenyldiol. Structures of the remaining PBDMBs were tentatively assigned by considering the retention times, mass spectra and amounts formed during UV irradiation of 2,2'-diMeO-BB 80 . In the third part of this study, blubber of marine mammals from Australia was analysed for PBDMBs using gas chromatography in combination with electron ionization mass spectrometry (GC/EI-MS) in the selected ion monitoring mode. In these samples, 2,2'-diMeO-BB 80 was found at concentrations of 200-1800ngg(-1) lipid weight (lw). The latter represents the highest concentration reported for this compound in environmental samples. 6,6'-diMeO BB 11, 2,2'-diMeO BB 36, and 2,6'-diMeO BB 36 were present at approximately 7ngg(-1) lipids, or 0.43-1.5% of diMeO-BB 80. No further PBDMBs were detected in the samples. The di- and triBDMBs identified in marine mammal blubber have not been reported as natural products. They may represent either new natural products or transformation products of 2,2'-diMeO-BB 80.  相似文献   
325.
The disposal of coal combustion residues (CCR) has led to a significant consumption of land in the West Balkan region. In Tuzla (Bosnia and Herzegovina) we studied previously soil-covered (farmed) and barren CCR landfills including management practises, field ageing of CCR and the transfer of trace elements into crops, wild plants and wastewaters. Soil tillage resulted in mixing of cover soil with CCR. Medicago sativa showed very low Cu:Mo ratios (1.25) which may cause hypocuprosis in ruminants. Total loads of inorganic pollutants in the CCR transport water, but not pH ( approximately 12), were below regulatory limits of most EU countries. Arsenic concentrations in CCR transport water were <2microgl(-1) whereas reductive conditions in an abandoned landfill significantly enhanced concentrations in leachates (44microgl(-1)). The opposite pattern was found for Cr likely due to large initial leaching of CrVI. Public use of landfills, including farming, should be based on a prior risk assessment due to the heterogeneity of CCR.  相似文献   
326.
The changing Arctic environment is affecting zooplankton that support its abundant wildlife. We examined how these changes are influencing a key zooplankton species, Calanus finmarchicus, principally found in the North Atlantic but expatriated to the Arctic. Close to the ice-edge in the Fram Strait, we identified areas that, since the 1980s, are increasingly favourable to C. finmarchicus. Field-sampling revealed part of the population there to be capable of amassing enough reserves to overwinter. Early developmental stages were also present in early summer, suggesting successful local recruitment. This extension to suitable C. finmarchicus habitat is most likely facilitated by the long-term retreat of the ice-edge, allowing phytoplankton to bloom earlier and for longer and through higher temperatures increasing copepod developmental rates. The increased capacity for this species to complete its life-cycle and prosper in the Fram Strait can change community structure, with large consequences to regional food-webs.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01667-y.  相似文献   
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Under stressful conditions (e.g. finding themselves on dry or moisture-saturated substrates) littoral talitrids (Crustacea, Amphipoda) demonstrate zonal orientation, in which they must promptly reach the optimal zone of the beach, the wet fringe near the shoreline. A relationship might therefore exist between the use of orientation and the frequency of such stressful conditions in the natural environment. Moreover, the efficiency of orientation toward the sea could be related to the possibility of using strategies other than zonal orientation in order to avoid stress. This study analysed the actual use and efficiency of orientation under natural conditions of four Talitrus saltator (Montagu, 1808) populations from Mediterranean and northern European Atlantic coasts with different ecological features. Orientation tests were carried out on the beach with all natural cues available. Then the same individuals underwent control experiments to study their sun orientation far from the sea in an experimental arena. The following results emerge from the comparison of the circular distributions: (1) marked differences among populations in the precision of zonal recovery under natural conditions; (2) a common solar orientation capacity in the control tests far from the sea; (3) different orientation choices of the same individuals according to the test conditions, natural or controlled. The habitat diversity of the four populations (amount, distribution and kind of detritus and wrack on the beach, degree of coastal erosion, orientation of the shoreline, human use of the beach) provides an ecological interpretation for the differences in orientation observed among populations. Received: 13 October 1997 / Accepted after revision: 26 April 1998  相似文献   
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