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41.
The complexity of development activities, in which the interactions between various forces often mean that outcomes are unpredictable and unanticipated, highlights the importance of objective and comprehensive evaluations. In the specific case of the evaluation of towns east and south of Colombo water supply projects, the findings have major implications for the implementation of the Millennium Development Goals, if the water-related objectives are to be fulfilled. The study found that 30% of the households of these towns that are receiving clean, piped water are not using it for drinking. Instead, they are continuing to drink contaminated well water. Whereas it is considered that the main beneficiaries of water supply projects have been women and people who are sick, elderly, or disabled, the general perception is that the health conditions of the families have not improved with the provision of clean water (in fact, many claim that their health conditions have deteriorated). In spite of the higher cost of the supplied water, people are willing to pay for it as long as the supply is reliable. 相似文献
42.
The paper presents an overview of the present situation of the Mexico City Metropolitan Area (MCMA). The analysis indicates an urgent need to radically improve the current water supply and wastewater management practices, to become sustainable. The MCMA is one of the most rapidly growing urban centers of the world, with a population of about 21 million people, a very high rate of immigration and numerous illegal settlements. In order to meet the increasing water demand, successive governments have focused almost exclusively on supply management and engineering solutions, which have resulted in investments of hundreds of millions of USD and the construction of major infrastructure projects for interbasin water transfer. Environmental, economic and social policies associated with water management are mostly inadequate and insufficient, which is resulting in increasing deterioration in the environment, health and socioeconomic conditions of a population living in one of the largest urban agglomerations of the world. Surprisingly, however, no long-term strategies on demand-management, reuse, conservation, and improved water-management practices have been developed so far. 相似文献
43.
本文分析了瑞典地区1961~2000年极端日降水量的空间尺度、区域变化和与之相关的天气类型.根据30km滞后距离计算的统计相关图估计年平均降水量、日降水量的99%分位值和平均年最大日雨量变化的空间尺度分别为100km、60~100km和40~70km.采用最大相似因子分析方法确定了82个站点极端降水量的区域相关.并发现有11个因子可以提供给最佳因子解决方案.极端事件发生时的天气类型是根据以逐日海平面气压为基础的客观系统划分的,并经过主观(包括锋面)修正.总体来看,极端降水事件的发生,63%在气旋类天气,32%在锋面类天气,3%在定向类天气,2%在反气旋类天气.然而,极端事件各种天气类型的发生频次不同地区之间有所不同. 相似文献
44.
Michelle Ramos-Robles Wesley Dáttilo Cecilia Díaz-Castelazo Ellen Andresen 《Die Naturwissenschaften》2018,105(3-4):29
Interactions between fleshy fruited plants and frugivores are crucial for the structuring and functioning of biotic communities, particularly in tropical forests where both groups are diverse and play different roles in network organization. However, it remains poorly understood how different groups of frugivore species and fruit traits contribute to network structure. We recorded interactions among 28 plant species and three groups of frugivores (birds, bats, and non-flying mammals) in a seasonal forest in Mexico to determine which species contribute more to network structure and evaluate the importance of each species. We also determined whether fruit abundance, water content, morphology traits, and fruiting phenology are related to network parameters: the number of interactions, species contribution to nestedness, and species strength. We found that plants did not depend on a single group of frugivores, but rather on one species of each group: the bird Pitangus sulphuratus, the bat Sturnira parvidens, and the non-flying mammal Procyon lotor. The abundance, size, and water content of the fruits were significantly related to the contribution to nestedness, number of interactions, and species strength index of plant species. Tree species and birds contributed mainly to the nested structure of the network. We show that the structure of plant-frugivore networks in this seasonal forest is non-random and that fruit traits (i.e., abundance, phenology, size, and water content) are important factors shaping plant-frugivore networks. Identification of the key species and their traits that maintain the complex structure of species interactions is therefore fundamental for the integral conservation of tropical forests. 相似文献
45.
Valente Tommaso Ventura Daniele Matiddi Marco Sbrana Alice Silvestri Cecilia Piermarini Raffaella Jacomini Carlo Costantini Maria Letizia 《Environmental science and pollution research international》2023,30(1):298-309
Environmental Science and Pollution Research - Microplastic pollution is one of the greatest environmental concerns for contemporary times and the future. In the last years, the number of... 相似文献
46.
Interactions of bacteria and fungi on decomposing litter: differential extracellular enzyme activities 总被引:10,自引:0,他引:10
Fungi and bacteria are key agents in plant litter decomposition in freshwater ecosystems. However, the specific roles of these two groups and their interactions during the decomposition process are unclear. We compared the growth and patterns of degradative enzymes expressed by communities of bacteria and fungi grown separately and in coexistence on Phragmites leaves. The two groups displayed both synergistic and antagonistic interactions. Bacteria grew better together with fungi than alone. In addition, there was a negative effect of bacteria on fungi, which appeared to be caused by suppression of fungal growth and biomass accrual rather than specifically affecting enzyme activity. Fungi growing alone had a high capacity for the decomposition of plant polymers such as lignin, cellulose, and hemicellulose. In contrast, enzyme activities were in general low when bacteria grew alone, and the activity of key enzymes in the degradation of lignin and cellulose (phenol oxidase and cellobiohydrolase) was undetectable in the bacteria-only treatment. Still, biomass-specific activities of most enzymes were higher in bacteria than in fungi. The low total activity and growth of bacteria in the absence of fungi in spite of apparent high enzymatic efficiency during the degradation of many substrates suggest that fungi provide the bacteria with resources that the bacteria were not able to acquire on their own, most probably intermediate decomposition products released by fungi that could be used by bacteria. 相似文献
47.
48.
Cecilia S. Carranza Carla L. Barberis Stella M. Chiacchiera Ana María Dalcero Carina E. Magnoli 《Journal of environmental science and health. Part. B》2016,51(1):35-43
Glyphosate-based herbicides are extensively used in Argentina's agricultural system to control undesirable weeds. This study was conducted to evaluate the culturable mycobiota [colony forming units (CFU) g?1 and frequency of fungal genera or species] from an agricultural field exposed to pesticides. In addition, we evaluated the tolerance of A. oryzae and nontoxigenic A. flavus strains to high concentrations (100 to 500 mM – 17,000 to 84,500 ppm) of a glyphosate commercial formulation. The analysis of the mycobiota showed that the frequency of the main fungal genera varied according to the analyzed sampling period. Aspergillus spp. or Aspergillus section Flavi strains were isolated from 20 to 100% of the soil samples. Sterilia spp. were also observed throughout the sampling (50 to 100%). Aspergillus section Flavi tolerance assays showed that all of the tested strains were able to develop at the highest glyphosate concentration tested regardless of the water availability conditions. In general, significant reductions in growth rates were observed with increasing concentrations of the herbicide. However, a complete inhibition of fungal growth was not observed with the concentrations assayed. This study contributes to the knowledge of culturable mycobiota from agricultural soils exposed to pesticides and provides evidence on the effective growth ability of A. oryzae and nontoxigenic A. flavus strains exposed to high glyphosate concentrations in vitro. 相似文献
49.
Claudia Cesaretti Luigina Spaccini Mariangela Rustico Cecilia Parazzini Chiara Doneda Thomas J. Re Andrea Righini 《黑龙江环境通报》2014,34(10):1015-1017
Hypochondroplasia (HCH) is a genetic skeletal dysplasia, inherited in an autosomal dominant fashion. About 50–70% of HCH patients have a mutation in FGFR3 gene and in the majority of cases it is a de novo mutation. Recent magnetic resonance imaging studies on relative large cohorts of HCH patients have showed a central nervous system involvement with a high incidence of characteristic temporal lobe and hippocampal abnormalities. To the best of our knowledge, this report shows the first magnetic resonance imaging prenatal detection of characteristic brain anomalies in a case of HCH, molecularly confirmed through postnatal FGFR3 analysis. © 2014 John Wiley & Sons, Ltd. 相似文献
50.