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51.
Hydropower is very important for electricity supply security in the European inter-connexion as well as for the economy of regions (primarily peripheral) that possess water resources. Its future may however be jeopardized by several factors: climate change, the development of new renewable energy, the creation of super and micro-grids, and progress in power storage technology. Energy and climate policy, as well as electricity market design and dynamics play a pivotal role.This article carries out a comprehensive analysis of all these factors and discusses the future of hydropower. This discussion follows an overview of the present situation and of future drivers. The technical, environmental, economic and political aspects of the problem are analyzed with an interdisciplinary approach. The stakes as well as the uncertainties are highlighted.The conclusion is that hydropower has a promising future, particularly in light of emerging sustainable energy policy, but that the risks should not be overlooked. Academics will find a comprehensive interdisciplinary analysis of hydropower in this article, whereas public bodies, communities and hydropower companies can identify the strategic variables that should be taken into consideration in the decision making process. The end of water concessions or authorizations is also evoked.  相似文献   
52.
Determining sources of neurotoxic metals in rural and urban soils is important for mitigating human exposure. Surface soil from four areas with significant clusters of mental retardation and developmental delay (MR/DD) in children, and one control site were analyzed for nine metals and characterized by soil type, climate, ecological region, land use and industrial facilities using readily available GIS-based data. Kriging, principal component analysis (PCA) and cluster analysis (CA) were used to identify commonalities of metal distribution. Three MR/DD areas (one rural and two urban) had similar soil types and significantly higher soil metal concentrations. PCA and CA results suggested that Ba, Be and Mn were consistently from natural sources; Pb and Hg from anthropogenic sources; and As, Cr, Cu, and Ni from both sources. Arsenic had low commonality estimates, was highly associated with a third PCA factor, and had a complex distribution, complicating mitigation strategies to minimize concentrations and exposures.  相似文献   
53.
Seasonal volatile organic compound emission data from loblolly pine (Pinus taeda) and Virginia pine (Pinus virginiana) were collected using branch enclosure techniques in Central North Carolina, USA. P. taeda monoterpene emission rates were at least ten times higher than oxygenated monoterpene and sesquiterpene emissions in all seasons. α-pinene and β-pinene were the most abundant emissions, while β-caryophyllene had the highest sesquiterpene emission rate from this species. β-phellandrene was the dominant compound emitted from P. virginiana, followed by the sesquiterpene β-caryophyllene. Sesquiterpene emissions from P. virginiana have not been reported in the literature previously. Summer sesquiterpene emissions from P. virginiana were nearly as high as monoterpene emissions, but were 4–12 times lower than monoterpene emissions in the other seasons. Oxygenated monoterpenes and 2-methyl-3-buten-2-ol were emitted at higher rates from P. taeda than from P. virginiana. Temperature response of the pinenes from P. taeda is similar to previously reported values used in emission models, while that for other compounds falls at the lower end of the previously reported range. Temperature response of all compounds from P. virginiana is in reasonable agreement with previously reported values from other pine species. There is evidence of light dependence of sesquiterpene emission after accounting for temperature response from both species. This effect is somewhat stronger in P. taeda. Bud break, needle expansion, and needle fall (and therefore wind events) seemed to increase monoterpene emission during non-summer seasons. In some instances springtime monoterpene emissions were higher than summertime emissions despite cooler temperatures. Emissions of individual compounds within monoterpene, oxygenated monoterpene, and sesquiterpene classes were highly correlated with each other. Compounds from different classes were much less correlated within each species. This is due to a varying temporal emission patterns for each BVOC class and suggests different production, storage, and emission controls for each. Analysis of enclosure blanks and diurnal patterns indicates that, despite precautions, disturbance due to the enclosure technique may still impact monoterpene emission rate estimates. This did not appear to affect sesquiterpene emissions.  相似文献   
54.
Abstract: The past three decades have seen major declines in populations of several species of amphibians at high elevations in eastern Puerto Rico, a region unique in the humid tropics because of the degree of environmental monitoring that has taken place through the efforts of U.S. government agencies. I examined changes in environmental conditions by examining time-series data sets that extend back at least into the 1980s, a period when frog populations were declining. The data include forest cover; annual mean, minimum, and maximum daily temperature; annual rainfall; rain and stream chemistry; and atmospheric-dust transport. I examined satellite imagery and air-chemistry samples from a single National Aeronautics and Space Administration aircraft flight across the Caribbean showing patches of pollutants, described as thin sheets or lenses, in the lower troposphere. The main source of these pollutants appeared to be fires from land clearing and deforestation, primarily in Africa. Some pollutant concentrations were high and, in the case of ozone, approached health limits set for urban air. Urban pollution impinging on Puerto Rico, dust generation from Africa ( potential soil pathogens), and tropical forest burning ( gaseous pollutants) have all increased during the last three decades, overlapping the timing of amphibian declines in eastern Puerto Rico. None of the data sets pointed directly to changes so extreme that they might be considered a direct lethal cause of amphibian declines in Puerto Rico. More experimental research is required to link any of these environmental factors to this problem.  相似文献   
55.
The nocturnal boundary layer in Houston, Texas was studied using a high temporal and vertical resolution tethersonde system on four nights during the Texas Air Quality Study II (TexAQS II) in August and September 2006. The launch site was on the University of Houston campus located approximately 4 km from downtown Houston. Of particular interest was the evolution of the nocturnal surface inversion and the wind flows within the boundary layer. The land–sea breeze oscillation in Houston has important implications for air quality as the cycle can impact ozone concentrations through pollutant advection and recirculation. The results showed that a weakly stable surface inversion averaging in depth between 145 and 200 m AGL formed on each of the experiment nights, typically within 2–3 h after sunset. Tethersonde vertical winds were compared with two other Houston data sets (High Resolution Doppler Lidar and radar wind profiler) from locations near the coastline and good agreement was found, albeit with a temporal lag at the tethersonde site. This comparison revealed development of a land breeze on three nights which began near the coastline and propagated inland both horizontally and vertically with time. The vertical temperature structure was significantly modified on one night at the tethersonde site after the land breeze wind shift, exhibiting near-adiabatic profiles below 100 m AGL.  相似文献   
56.
57.
The success or failure of rural water services in the developing world is a result of numerous factors that interact in a complex set of connections that are difficult to separate and identify. This research effort presented a novel means to empirically reveal the systemic interactions of factors that influence rural water service sustainability in the municipalities of Darío and Terrabona, Nicaragua. To accomplish this, the study employed graphical modeling to build and analyze factor networks. Influential factors were first identified by qualitatively and quantitatively analyzing transcribed interviews from community water committee members. Factor influences were then inferred by graphical modeling to create factor network diagrams that revealed the direct and indirect interaction of factors. Finally, network analysis measures were used to identify “impact factors” based on their relative influence within each factor network. Findings from this study elucidated the systematic nature of such factor interactions in both Darío and Terrabona, and highlighted key areas for programmatic impact on water service sustainability for both municipalities. Specifically, in Darío, the impact areas related to the current importance of water service management by community water committees, while in Terrabona, the impact areas related to the current importance of finances, viable water sources, and community capacity building by external support. Overall, this study presents a rigorous and useful means to identify impact factors as a way to facilitate the thoughtful planning and evaluation of sustainable rural water services in Nicaragua and beyond.  相似文献   
58.
In this research, a simple package called CPR 2.0 software was developed according to the algorithm suggested by AIChE/CCPS and implemented using Compaq Visual Fortran (CVF 6.6) programming language and METFOR 3.0 Fortran 90/95 Library. This multipurpose software includes nine sets of programs that can be used in combination or separately to calculate physical, effect, and vulnerability consequences; their results can also be easily processed into different tables and figures. A set of three-dimensional (3D) gas release contours with different concentration isosurfaces and transient dispersion states floating above a local map can be easily observed from different angles in order to facilitate emergency response planning and educational training. The software has been benchmarked with CHEMS-PLUS software via a methane release case and the result from the two packages is compared and analyzed.  相似文献   
59.
This study proposes and tests a meso‐level model of deep acting in work teams that draws on emotional contagion theory to explain how shared means of complying with display rules can arise in work teams. We argue that the presence of influential deep actors can lead to greater convergence (lower dispersion) on individual deep acting in the team. That is, team members behave more similarly. When a team has greater convergence, deep acting by individual members should be related to lower emotional exhaustion and higher job satisfaction and in‐role performance. In a sample of mature work teams, these hypotheses received general support. Our findings suggested that team‐level deep acting effects can foster benefits for team members (lower emotional exhaustion and higher satisfaction) and organizations (higher job performance). Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
60.
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