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101.
To be able to survive, marine macroalgae in shallow coastal waters need mechanisms for short-term acclimation to fast changes in their environment. Of major importance are mechanisms that regulate the efficiency of photosynthesis by protecting PS II from photo-oxidative damage. Carotenoids, xanthophyll cycles and non-photochemical quenching (NPQ) are central constituents of such protection mechanisms. Red algae as a group do not have a universal carotenoid composition. We screened ten red algal species and selected two species, originating from similar ecological conditions but with different carotenoid compositions, for use in irradiance-acclimation experiments. We selected the tropical intertidal species Gracilaria domingensis and Kappaphycus alvarezii with antheraxanthin and lutein as major xanthophylls, respectively. Simultaneous in vivo fluorescence and O2 evolution experiments were performed at different irradiance levels, which allowed a direct comparison of overall photosynthetic performance with NPQ. Interconversions of xanthophylls (violaxanthin, zeaxanthin, β-cryptoxanthin and one unidentified carotenoid) did occur in G. domingensis, but not in response to sudden exposure to light. Thus, NPQ was not correlated with any xanthophyll cycle during short-term acclimation to light. G. domingensis had five times higher weight-specific photosynthetic rates than K. alvarezii, which can be explained by the thicker thallus of K. alvarezii. Chlorophyll-specific gross photosynthetic rates were higher in K. alvarezii, but net rates were the same for both species. G. domingensis showed an immediate strong onset of NPQ upon exposure to irradiance, followed by downregulation to the NPQ level required. In K. alvarezii NPQ increased slowly until the required NPQ level was reached. At high irradiance G. domingensis downregulated photosynthesis while K. alvarezii continued to produce O2 even at 2,000 μmol photons m−2 s−1 without NPQ increase. The strategy of K. alvarezii may provide short-term gains but with the risk of oxidative damage. The fast onset of NPQ in G. domingensis even at subsaturating irradiance as well as downregulation of photosynthesis when NPQ is saturated might provide this species with a competitive advantage under conditions of changing irradiance in the field.  相似文献   
102.
This paper reviews the evolution of energy use in Denmark since the early 1970s, in order to shed light on the future path of energy use in Denmark, with particular emphasis on the role of energy efficiency. Improvements in end-use energy efficiency reduced primary energy requirements in Denmark by 22% between 1972 and 1988. This change accounts for two-thirds of the decline in the ratio of energy use to gross domestic product that occurred during this time: the rest of the decline was caused by changes in the mix of goods and services produced and consumed by the Danes. Total energy savings achieved between 1972 and 1988 in Denmark ranked among the highest measured in any major OECD country. Overall, most of the energy savings in Denmark were brought about through improvements in technology. Short-term changes in consumer behaviour were significant in reducing energy needs for space heating and transport. An important stimulus for improved efficiency was higher energy prices, led in no small part by significant taxes imposed on small consumers of heating oil, electricity and motor fuels.  相似文献   
103.
A template transfer method (TTM) and a fiber fixation technique were established for fiber handling and micro tensile stage mounting of aligned and non-aligned electrospun fiber mats. The custom-made template had been precut to be mounted on a variety of collectors, including a rapidly rotating collector used to align the fibers. The method eliminated need for direct physical interaction with the fiber mats before or during the tensile testing since the fiber mats were never directly clamped or removed from the original substrate. By using the TTM it was possible to measure the tensile properties of aligned poly(methyl methacrylate) (PMMA) fiber mats, which showed a 250?% increase in strength and 450?% increase in modulus as compared to a non-aligned system. The method was further evaluated for aligned PMMA fibers reinforced with cellulose (4 wt%) prepared as enzymatically derived nanofibrillated cellulose (NFC). These fibers showed an additional increase of 30?% in both tensile strength and modulus, resulting in a toughness increase of 25?%. The fracture interfaces of the PMMA?CNFC fibers showed a low amount of NFC pull-outs, indicating favorable phase compatibility. The presented fiber handling technique is universal and may be applied where conservative estimates of mechanical properties need to be assessed for very thin fibers.  相似文献   
104.
Environmental problems are a function of the process of economic development and the ability to mitigate the problems through regulation. An historical analysis helps to show how the problems have been solved thus far. The objective of this investigation is to present an overview of environmental problems and the corresponding regulations in Western Europe during the 1980s. Environmental problems for 18 Western European countries were identified from abstracts from a data base on environmental literature. The 1977 findings were systematized on the basis of 20 key words according to source and impact, and a new data base was established. The data showed that the main environmental problems in Western Europe were: energy production/acid rain, nuclear power/waste, air pollution/climate, heavy metals, pesticides, water pollution, solid waste, and unforeseen accidents. Many environmental problems are common to most European countries. Regulatory measures differ significantly. In some countries environmental regulations are largely limited to the implementation of European Economic Community (EEC) directives. We have supplemented the national analyses with an examination of existing and proposed EEC regulations along with interviews with civil servants in the EEC Commission. In the 1980s, EEC environmental regulations were similar to environmental regulations in some member states. It is expected that future EEC regulations will be less reflective of those of individual member states.  相似文献   
105.
Experiments were conducted at the Asp? Hard Rock Laboratory in order to improve the understanding of radionuclide retention properties of fractured crystalline bedrock in the 10-100 m scale (TRUE Block Scale Project, jointly funded by ANDRA, ENRESA, Nirex, JNC, Posiva and SKB). A series of tracer experiments were performed using sorbing tracers in three different flow paths. The different flow paths had Euclidian lengths of 14, 17 and 33 m, respectively, and one to three water conducting structures. Four tests were performed using different cocktails made up of radioactive sorbing tracers (22,24Na+, 42K+, 47Ca2+, 85Sr2+, 83,86Rb+, 131,133Ba2+ and 134,137Cs+). For each tracer injection, the breakthrough of sorbing tracers was compared to the breakthrough of a conservative tracer, 82Br-, 131I-, HTO and 186ReO4-, respectively. In the two longer flow paths, no breakthrough of 83Rb+ and 137Cs+ was observed after 8 months of pumping. Selected tracer tests were subject to basic modelling in which a one-dimensional (1D) advection-dispersion model, including surface sorption, and an unlimited matrix diffusion were used for the interpretation of the results. The results of the modelling indicated that there is a slightly higher mass transfer into a highly porous material in the block-scale experiment compared with in situ experiments performed over shorter distances and significantly higher than what would have been expected from laboratory data obtained from studies of the interactions in nonaltered intact rock.  相似文献   
106.
Knowledge of past fire regimes is crucial for understanding the changes in fire frequency that are likely to occur during the coming decades as a result of global warming and land-use change. This is a key issue for the sustainable management of forest biodiversity because fire regimes may be controlled by vegetation, human activities, and/or climate. The present paper aims to reconstruct the pattern of fire frequency over the Holocene at three sites located in the same region in the northern Swedish boreal forest. The fire regime is reconstructed from sedimentary charcoal analysis of small lakes or ponds. This method allows fire events to be characterized, after detrending the charcoal influx series, and allows estimation of the time elapsed between fires. The long-term fire regime, in terms of fire-free intervals, can thus be elucidated. At the three sites, the mean fire-free intervals through the Holocene were long and of similar magnitude (approximately 320 years). This similarity suggests that the ecological processes controlling fire ignition and spread were the same. At the three sites, the intervals were shorter before 8600 cal yr BP (calibrated years before present), between 7500 and 4500 cal yr BP, and after 2500 cal yr BP. Geomorphological and vegetation factors cannot explain the observed change, because the three sites are located in the same large ecological region characterized by Pinus sylvestris-Ericaceae mesic forests, established on morainic deposits at the same elevation. Archaeological chronologies also do not match the fire chronologies. A climatic interpretation is therefore the most likely explanation of the long-term regional pattern of fire. Although recent human activities between the 18th and the 20th centuries have clearly affected the fire regime, the dominant factor controlling it for 10000 years in northern Sweden has probably been climatic.  相似文献   
107.
The increasing need for biomass for energy and feedstocks, along with the need to divert organic methane generating wastes from landfills, may provide the economic leverage necessary to return this type of marginal land to functional and economic use and is strongly supported by policy at the European Union (EU) level. The use of land to produce biomass for energy production or feedstocks for manufacturing processes (such as plastics and biofuels) has, however, become increasingly contentious, with a number of environmental, economic, and social concerns raised. The REJUVENATE project has developed a decision support framework to help land managers and other decision makers identify potential concerns related to sustainability and what types of biomass reuse for marginal land might be possible, given their particular circumstances. The decision‐making framework takes a holistic approach to decision making rather than viewing biomass production simply as an adjunct of a planned phytoremediation project. The framework is serviceable in Germany, Sweden, and the United Kingdom. These countries have substantive differences in their land and biomass reuse circumstances. However, all can make use of the set of common principles of crop, site, value, and project risk management set out by REJUVENATE. This implies that the framework should have wider applicability across the EU. This article introduces the decision support framework. © 2011 Wiley Periodicals, Inc.  相似文献   
108.
In this perspective article, we provide recommendations for strengthening the policy framework for protecting the Baltic Sea from agricultural nutrient pollution. The most striking weakness is the lax implementation of prescribed abatement measures, particularly concerning manure management, in most countries. Institutions of the EU should also be leveraged for achieving Baltic Sea Action Plan (BSAP) goals. In contrast to the Helsinki Convention, the European Union has economic, political and legal mandates to further implementation and compliance. Equally important is the need for strengthening of local institutions, particularly Water Boards and independent agricultural advisory services in the eastern Baltic Sea Region countries. There is also an urgent need for implementation of voluntary land-use measures where EU funding available to farmers is more broadly and effectively used by providing it on the basis of estimated abatement performance, which can be realized through modelling. The enormous potential for funding performance-based schemes, manure management infrastructure and advisory services through the EU’s Common Agricultural Policy are currently underutilized.Supplementary Informationhe online version contains supplementary material available at 10.1007/s13280-021-01573-3.  相似文献   
109.
The impact on a population from an event resulting in dispersal and deposition of radionuclides in an urban area could be significant, in terms of both the number of people affected and the economic costs of recovery. The use of computer models for assessment of urban contamination situations and remedial options enables the evaluation of a variety of situations or alternative recovery strategies in contexts of preparedness or decision-making. At present a number of models and modelling approaches are available for different purposes. This paper summarizes the available modelling approaches, approaches for modelling countermeasure effectiveness, and current sources of information on parameters related to countermeasure effectiveness. Countermeasure information must be applied with careful thought as to its applicability for the specific situation being modelled. Much of the current information base comes from the Chernobyl experience and would not be applicable for all types of situations.  相似文献   
110.
Ecosystem services (ES) is a valuable concept to be used in the planning and management of social–ecological landscapes. However, the understanding of the determinant factors affecting the interaction between services in the form of synergies or trade-offs is still limited. We assessed the production of 16 ES across 62 municipalities in the Norrström drainage basin in Sweden. We combined GIS data with publically available information for quantifying and mapping the distribution of services. Additionally, we calculated the diversity of ES for each municipality and used correlations and k-means clustering analyses to assess the existence of ES bundles. We found five distinct types of bundles of ES spatially agglomerated in the landscape that could be explained by regional social and ecological gradients. Human-dominated landscapes were highly multifunctional in our study area and urban densely populated areas were hotspots of cultural services.  相似文献   
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