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There is a frequent need in the environmental sciences to show the similarity of the results given by two analytical methods. This cannot, however, be done within the conventional 'there is a difference' statistical hypothesis setting of, among others, Student's t-test. We demonstrate here a more appropriate approach that originates from drug testing and that can be applied with standard statistical software. It is a challenging approach, as it requires quantification of the similarity limit. If no pre-determined value is given for similarity, a potential data-supported similarity limit can be explored from the data. The approach has numerous other potential application areas, e.g. parallelism of regression slopes, homogeneity of variances and lack of interaction. 相似文献
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Water resources and land use are closely linked with each other and with regional climate, assembling a very complex system. The understanding of the interconnecting relations involved in this system is an essential step for elaborating public policies that can effectively lead to the sustainable use of water resources. In this study, an integrated modelling framework was assembled in order to investigate potential impacts of agricultural expansion and climate changes on Irrigation Water Requirements (IWR) in the Taita Hills, Kenya. The framework comprised a land use change simulation model, a reference evapotranspiration model and synthetic precipitation datasets generated through a Monte Carlo simulation. In order to generate plausible climate change scenarios, outputs from General Climate Models were used as reference to perturbing the Monte Carlo simulations. The results indicate that throughout the next 20 years the low availability of arable lands in the hills will drive agricultural expansion to areas with higher IWR in the foothills. If current trends persist, agricultural areas will occupy roughly 60% of the study area by 2030. This expansion will increase by approximately 40% the annual water volume necessary for irrigation. Climate change may slightly decrease crops' IWR in April and November by 2030, while in May a small increase will likely be observed. The integrated assessment of these environmental changes allowed a clear identification of priority regions for land use allocation policies and water resources management. 相似文献
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The paper describes and analyses the 100 year development of water supply and sanitation and the lessons learnt in Porvoo, a municipality of 46,000 people on the southern coast of Finland. In urban areas the municipality‐owned utility has always dominated. Over 90 per cent of the investments for the recent wastewater treatment plant went into services, equipment and goods bought from the private sector through 12 tenders, all based on competition. In the neighbouring rural areas, recently merged with the city, there are nine consumer‐managed, non‐profit water cooperatives that buy water in bulk from the city water utility. Although the solutions are based on local conditions and subsidiarity, some more general principles are also highlighted and discussed. Past decisions inevitably also affect future development options. 相似文献
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Petri T. Niemel? Anssi Vainikka Sonja Lahdenper? Raine Kortet 《Behavioral ecology and sociobiology》2012,66(5):645-652
Population density regulates the strength of intraspecific competition and may thereby be reflected in life-history variables,
such as development time, growth rate, or investment in immune defense. However, population density may also affect the fitness
payoffs of different behaviors and consequently shape the development of personality. Here we studied if population density
during nymphal development (one, four, or ten individuals raised together) affects the level of boldness, measured as the
latency time to recover from freezing and emerge from a shelter, aggressiveness towards conspecifics or their correlation
at the adult stage in the field crickets, Gryllus integer. In addition, we tested if individuals invest more resources in immune function or speed up their development in response
to a high conspecifics density during ontogeny. Nymphal density did not affect adult boldness or aggressiveness towards conspecific
males per se, but these variables showed a negative association, i.e., indicated an unconventional behavioral syndrome in
the highest density treatment. Supporting the effectiveness of density treatments in inducing plastic responses, individuals
reached maturity sooner and invested more resources in immune function in the highest nymphal density group compared to groups
consisting of one or four individuals. Our results suggest that population density may play an important role in shaping both
the realized life history and development of behavioral syndromes. 相似文献