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91.
In this paper an overview is presented of the landscape development of the low-lying parts of The Netherlands. It is shown that water has played an important role in this development. Since prehistoric times, but especially since about 800 AD, man has gradually occupied the low lands along the sea and the main rivers. Through these settlements a chain of actions and reactions of man and his physical environment was set into motion. This chain of events is briefly outlined. It is stated and also illustrated that not only the characteristics of the landscape of the western part of The Netherlands, but also the organization of the Dutch society has been influenced strongly by manÕs need to cope with the omnipresence of water and the threats and opportunities posed by that. It is concluded that the outlined events can only be understood properly if interdisciplinary research takes a more prominent role than it does now.  相似文献   
92.
93.
A 6-month field intercomparison study on precipitation measurements was performed at Schagerbrug near the west coast in the Netherlands. Twenty bulk sampling systems and two wet-only samplers were evaluated on accuracy, sampling strategy and performance under field conditions. Bulk precipitation fluxes of NO3-, NH4+, H+ and Kjeldahl-N generally could be determined with a greater accuracy than bulk precipitation fluxes of SO4(2-), Na+, Cl-, Mg2+, Ca2+, Alkalinity and H+. Bulk precipitation fluxes of K+ generally had the lowest accuracy. Only 20% of the sampling systems differed less than 10% from the best estimate, whereas most systems (60%) differed more than 20% from the best estimate. The inaccuracy induced by the sampling system appeared to be much larger than that resulting from the analysis of the samples by different laboratories as determined by ring-tests.  相似文献   
94.
We investigate social circles in intra‐firm settings. First, we argue that social circles are inhabited by individuals whose attitudes display fit with the objectives of the social circle rather than more self‐centered instrumentalism or calculation. For a test of this hypothesis, we distinguish between friendship circles and strategy‐influence circles. We find that friendship circle membership is positively associated with attitudes that display empathic concern but negatively with more instrumental attitudes, whereas strategy‐influence circle membership is positively associated with attitudes that display long‐term ambition but negatively with attitudes that display short‐term calculation. Second, we argue and find that membership of social circles affects individual performance (social circles foster the exchange of information, for which we find clear evidence), albeit not necessarily in a linear fashion. Our new insights into social circle membership and performance implications can guide individuals in seeking access to such social circles and can aid management in understanding and perhaps influencing intra‐firm knowledge flows. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   
95.
The recovery from acidification has led to the demand for more precise criteria for classification of acidification. The Swedish Environmental Protection Agency has revised Sweden’s Ecological Quality Criteria for acidification to improve the correlation between the chemical acidification criteria and biological effects. This paper summarises the most relevant findings from several of the studies commissioned for this revision. The studies included data on water chemistry in 74 reference lakes in southern Sweden with data on fish in 61 of the lakes, as well as data on littoral fauna in 48 lakes. We found that the acidity variable most strongly correlated to the biota was the median pH from the current year. Our results probably do not reflect the mechanisms behind the negative effects of acidity on the biota, but are fully relevant for evaluation of monitoring data. The biogeochemical models used for predicting acidification reference conditions generate a pre-industrial buffering capacity. In order to get an ecologically more relevant criteria for acidification based on pH, we transferred the estimated change in buffering capacity into a corresponding change in pH. A change of 0.4 units was defined as the threshold for acidification. With this criterion a considerably lower number of Swedish lakes were classified as acidified when compared with the present Ecological Quality Criteria.  相似文献   
96.
This paper analyses the development and implementation of biomass gasifiers in India. Based on literature reviews and fieldwork, an historical narrative is presented starting with laboratory experiments in the 1980s up to commercial applications after 2000. This narrative is analysed using the Strategic Niche Management framework. We conclude with the benefit of hindsight that technological expectations where generally too high. The biomass gasification technology is not easy to design and operate and needs to be embedded in a stable institutional set up to allow learning, knowledge transfer, regulation and funding. We also conclude that, in contrast with theoretical predictions, up-scaling the niche suffers from regime instability rather than regime stability, as there is a need to give more security to investors and end-users. For instance through setting clear and long-term condition for grid-connected biomass gasification systems and feed-in schemes. Up-scaling through local off-grid applications where enough technical competence is available is the most likely trend in the near future.  相似文献   
97.
Deposition is one of the main loss terms for ammonia and ammonium from the atmosphere. It is also the input for ecosystems that can lead to drastic changes and effects. Deposition networks are needed to evaluate the need and the effect of policies to reduce nitrogen emissions, but also for studying deposition parameters and for developing deposition models. As with ambient concentrations of ammonia, deposition, especially dry deposition, varies strongly in space and in time. Furthermore, the bi-directional surface-atmosphere exchange of ammonia makes the combination of ambient concentration measurements with inferential models inadequate. Developing deposition monitoring networks with reasonable accuracy and representativeness is therefore not straightforward. In Europe several projects have addressed deposition monitoring. From these results it is concluded that a monitoring strategy should consist of a network with a limited amount of super sites combined with a larger number of sites where low cost methods are applied, together with models for generalisation.  相似文献   
98.
Dry deposition of gases and particles to forests is influenced by factors influencing the turbulent transport, such as wind speed, tree height, canopy closure, LAI, etc. as well as by factors influencing surface condition, such as precipitation, relative humidity, global radiation, etc. In this paper, an overview of these factors is given and it is shown which are the most important determining temporal and spatial variation of dry deposition of sodium and sulphur. Furthermore, it is evaluated how well current deposition models are able to describe the temporal and spatial variation in dry deposition. It is concluded that the temporal variation is not modelled well enough, because of limited surface-wetness exchange parameterisations. The influence of forest characteristics are modelled reasonably well, provided enough data describing the forests and the spatial variation in concentration is available. For Europe these data are not available. The means to decrease the atmospheric deposition through forest management is discussed.  相似文献   
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