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101.
102.
Rice-paddies are regarded as one of the main agricultural sources of N 2O and NO emissions. To date, however, specific N2O and NO production pathways are poorly understood in paddy soils. ^15N-tracing experiments were carded out to investigate the processes responsible for N2O and NO production in two paddy soils with substantially different soil properties. Laboratory incubation experiments were carried out under aerobic conditions at moisture contents corresponding to 60% of water holding capacity. The relative importance of nitrification and denitrification to the flux of NaO was quantified by periodically measuring and comparing the enrichments of the N2O, NH~-N and NO3-N pools. The results showed that both N2O and NO emission rates in an alkaline paddy soil with clayey texture were substantially higher than those in a neutral paddy soil with silty loamy texture. In accordance with most published results, the ammonium N pool was the main source of N2O emission across the soil profiles of the two paddy soils, being responsible for 59.7% to 97.7% of total N2O emissions. The NO3-N pool of N2O emission was relatively less important under the given aerobic conditions. The rates of N2O emission from nitrification (N2On) among different soil layers were significantly different, which could be attributed to both the differences in gross N nitrification rates and to the ratios of nitrified N emitted as NzO among soil layers. Furthermore, NO fluxes were positively correlated with the changes in gross nitrification rates and the ratios of NO/N2O in the two paddy soils were always greater than one (from 1.26 to 6.47). We therefore deduce that, similar to N2O, nitrification was also the dominant source of NO in the tested paddy soils at water contents below 60% water holding capacity.  相似文献   
103.
104.
ABSTRACT: The 18-year precipitation record from the dense gage network on the Reynolds Creek Experimental Watershed located in southwest Idaho was used to determine the spatial distribution of annual and monthly precipitation on a mountainous watershed. Analyses of these data showed a linear relationship between annual amounts and elevation. This relationship was best when the gages were grouped into downwind and upwind sites. This grouping was appropriate because most of the winter storms moved over the watershed from the west and southwest, and the heaviest precipitation was on the west (downwind) side of the watershed. Gage sites along the western and southern watershed borders were most representative of the upwind gages on the east side, because they measured the precipitation from the air moving upwind onto the watershed. The maximum annual precipitation on the watershed was just leeward of the western watershed boundary. The monthly precipitation and elevation relationship was also best represented by grouping the gage sites into upwind and downwind sites. However, during the summer when there are only small amounts of pre cipitation and thunderstorms are the source of most precipitation, one equation can be used to represent the elevation relationship. This study also showed that the log-normal distribution could be used to generate the annual synthetic series, and the cube-root-normal distribution could be used to generate monthly synthetic series for all locations on the watershed.  相似文献   
105.
ABSTRACT: In the past five years, USDA and EPA programs became major players in implementing watershed programs. The 1996 Farm Bill for the first time required that USDA assistance for farmers address priority environmental needs on a site‐specific, or watershed, basis. USDA involves farmers and other players in locally run watershed programs and focuses cost share and incentive payments on nutrient planning, riparian protection, and other practices prioritized to most efficiently achieve watershed goals. As a result, USDA has become a funding source for environmental initiatives targeted to watersheds, as well as a technical resource that attempts to support more efficient use of federal and state environmental expenditures. Analysis identifies institutional and technical barriers to targeting the very limited, new assistance and suggests how those barriers are being addressed by some innovative programs. Since Total Maximum Daily Load (TMDL) and other state run programs face many of the same challenges of ranking watersheds, setting goals, and finding cost effective remedies, this paper identifies a very close fit between the new federal programs and other watershed programs.  相似文献   
106.
107.
When social scientists conduct research in organizations, they engage in relationships with respondents in order to obtain information. For studies of race relations in organizations, questions arise about how researchers take account of their organizational and racial group memberships. This field experiment tests hypotheses derived from embedded intergroup relations theory about the effects of questionnaire administration procedures and race of respondents on response rate, reactions to the research, perceptions of race relations, and satisfaction. Results provided support for several hypotheses that predict respondents will experience the research and respond differently when they answer questionnaires in race alike group meetings than when they report anonymously by mail.  相似文献   
108.
This study examines domestic media’s coverage of foreign wildfires from a climate change perspective. It explores Swedish newspapers’ coverage of wildfires in Australia, the Mediterranean region, and the USA during a three-year period (February 2013–March 2016), focusing on how and to what extent climate change is viewed as an underlying cause. A central result is that climate change is mentioned far more often in the case of Australian wildfires than of fires in the other two regions. Another finding is that the climate change issue became more prominent after a severe domestic wildfire in 2014. These observations are also examined qualitatively through a combined frame and discourse study where the importance of foreign news values, the use of foreign sources, cultural proximity/distance, and domestication procedures are analysed. In conclusion, foreign, domestic, and cultural factors in climate change reporting in relation to extreme events are further discussed.  相似文献   
109.
Protecting our water resources in terms of quality and quantity is considered one of the big challenges of the twenty-first century, which requires global and multidisciplinary solutions. A specific threat to water resources, in particular, is the increased occurrence and frequency of flood events due to climate change which has significant environmental and socioeconomic impacts. In addition to climate change, flooding (or subsequent erosion and run-off) may be exacerbated by, or result from, land use activities, obstruction of waterways, or urbanization of floodplains, as well as mining and other anthropogenic activities that alter natural flow regimes. Climate change and other anthropogenic induced flood events threaten the quantity of water as well as the quality of ecosystems and associated aquatic life. The quality of water can be significantly reduced through the unintentional distribution of pollutants, damage of infrastructure, and distribution of sediments and suspended materials during flood events. To understand and predict how flood events and associated distribution of pollutants may impact ecosystem and human health, as well as infrastructure, large-scale interdisciplinary collaborative efforts are required, which involve ecotoxicologists, hydrologists, chemists, geoscientists, water engineers, and socioeconomists. The research network “project house water” consists of a number of experts from a wide range of disciplines and was established to improve our current understanding of flood events and associated societal and environmental impacts. The concept of project house and similar seed fund and boost fund projects was established by the RWTH Aachen University within the framework of the German excellence initiative with support of the German research foundation (DFG) to promote and fund interdisciplinary research projects and provide a platform for scientists to collaborate on innovative, challenging research. Project house water consists of six proof-of-concept studies in very diverse and interdisciplinary areas of research (ecotoxicology, water, and chemical process engineering, geography, sociology, economy). The goal is to promote and foster high-quality research in the areas of water research and flood-risk assessments that combine and build off-laboratory experiments with modeling, monitoring, and surveys, as well as the use of applied methods and techniques across a variety of disciplines.  相似文献   
110.
This research uses a social identity analysis to predict employee creativity. We hypothesized that team identification leads to greater employee creative performance, mediated by the individual's creative effort. We hypothesized that leader inspirational motivation as well as leader team prototypicality would moderate the relationship between identification and creative effort. Consistent with these predictions, data based on 115 matched pairs of employee‐leader ratings in a research and development context showed an indirect relationship between team identification and creative performance mediated by creative effort. The analyses also confirmed the expected moderated relationships. Leader inspirational motivation enhanced the positive association between identification and creative effort, especially when leader prototypicality was high. We discuss the value of social identity analyses of employee creativity and of the integration of social identity and transformational leadership analyses. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
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