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In recent decades, many changes have occurred in the approach to financing and operating water services in developing countries. The demand‐responsive approach is now adopted in many countries in a context of donor‐supported decentralization processes, which gives more responsibility to end users. However, the government's responsibility at different levels is enforced by the international recognition of the human right to water. This paper examines specific actions that build the role of local government authorities in this scenario. A collaboration between an international NGO and a rural district in Tanzania from 2006 to 2009 is used as an action research case study that is representative of local capacity‐building needs in decentralized contexts and rural areas. Three main challenges were detected: i) lack of reliable information; ii) poor allocation of resources in terms of equity; and iii) lack of long‐term community management support from the district. Two mechanisms were established: i) water point mapping as a tool for information and planning; and ii) a District Water and Sanitation Unit Support (DWUS) for community management. The results show how the framework provided by the goal of human right to water helps to define useful strategies for equity‐oriented planning and post‐project support at the local level.  相似文献   
13.
The study of extreme values and prediction of ozone data is an important topic of research when dealing with environmental problems. Classical extreme value theory is usually used in air-pollution studies. It consists in fitting a parametric generalised extreme value (GEV) distribution to a data set of extreme values, and using the estimated distribution to compute return levels and other quantities of interest. Here, we propose to estimate these values using nonparametric functional data methods. Functional data analysis is a relatively new statistical methodology that generally deals with data consisting of curves or multi-dimensional variables. In this paper, we use this technique, jointly with nonparametric curve estimation, to provide alternatives to the usual parametric statistical tools. The nonparametric estimators are applied to real samples of maximum ozone values obtained from several monitoring stations belonging to the Automatic Urban and Rural Network (AURN) in the UK. The results show that nonparametric estimators work satisfactorily, outperforming the behaviour of classical parametric estimators. Functional data analysis is also used to predict stratospheric ozone concentrations. We show an application, using the data set of mean monthly ozone concentrations in Arosa, Switzerland, and the results are compared with those obtained by classical time series (ARIMA) analysis.  相似文献   
14.
The presence of cyanotoxins, mainly microcystins (MCs), in surface freshwater represents a serious health risk to aquatic organisms living in the water body, as well as terrestrial animals and plants that are in contact with contaminated water. Consequently, the use of MCs contaminated water for irrigation represents a hazard for cultivated plants and could induce severe economical losses due to crops’ yield reduction. The experimental approach undertaken in this work was exposing Vicia faba seedlings (inoculated with a Rhizobium strain resistant to MCs), to water supplemented with cyanobacterial crude extract containing total microcystins at a concentration of 50 and 100 μg/L (environmental relevant concentrations of MCs dissolved in the raw irrigation water from Lalla Takerkoust Lake-Marrakesh region). After chronic MCs exposure (2 months), biological and physiological parameters (plant growth, nitrogen uptake, mineral assimilation, and oxidative defense mechanisms) were evaluated. The results obtained showed evidence that chronic exposure to cyanobacterial bloom extract containing MCs strongly affected the physiological and biological plants activities; reduction of dry matter, photosynthetic activity, nodule number, and nitrogen assimilation. At the same time, an increase of oxidative stress was observed, as deduced from a significant increase of the activities of peroxidase, catalase, polyphenoloxidase, and phenylalanine ammonia lyase in leaves, roots, and nodules of faba bean plants exposed to cyanotoxins, especially at 100 μg/L of MCs. This experimentation constitutes a simulation of the situation related to cyanotoxins chronic exposure of seedlings—plants via the contaminated irrigation water. For this reason, once should take into consideration the possibility of contamination of agricultural crops and the quality of irrigation water should be by the way monitored for cyanotoxins biohazard.  相似文献   
15.
Since the 1940s, some sectors of the sand dune barriers of Buenos Aires Province have been forested to fix the sand in the neighborhoods of resort villages. Man took advantage of the maritime climate and the shallow groundwater to introduce pine forests. Today, these forests reach more than 20 m in height and have developed soils of more than 0.05 m in thickness on former arid sands. Field data were referred to Landsat (TM) composite and Normalized Difference of Vegetation Index, NDVI, images to calculate forest density and covered area. Considering published tables of wood density for each species, the amount of total carbon storage was estimated on 318 t C ha-1 (Mg=106 g) in biomass and 86 t C ha-1 in soils. The three areas analyzed at Miramar, Necochea and Claromecó have captured 658,868 t of carbon in the last 50 years. It is estimated that 150,000,000 t C could be sequestered within temperate dune barriers of Argentina, Uruguay and Brazil. Besides this ecological point of view, there is an important socio-economic factor that cannot be excluded.Presented at and revised subsequent to the 4th LOICZ Open Science Meeting, Bahía Blanca, Argentina. October 1999.  相似文献   
16.
With the aim of obtaining an index of coastal water quality, a methodological procedure based on numerical classification and discriminant analysis is presented. The procedure was applied to nutrient data (ammonia, nitrite, nitrate, and phosphate) analyzed along the coastal waters of a Spanish tourist area. Using numerical classification, three levels of nutrient loading were revealed, characterizing oligotrophic, mesotrophic, and potentially eutrophic waters. Discriminant analysis was shown to be an effective methodological tool in the discrimination between trophic groups. For every group, the discriminant procedure generated the centroids. The centroids representing oligotrophic and potentially eutrophic conditions were used to establish the two extremes of the continuum of mesotrophic conditions in these coastal waters: Standardizing values from -1 to 1, the centroids for oligotrophic and potentially eutrophic waters yielded an interval that defined the range of mesotrophic conditions. This interval is proposed as a water quality index. The ability of the coastal water quality index to successfully predict mesotrophic conditions was proved with random samples.  相似文献   
17.
The contamination and vertical distribution of As, Cd, Cr, Cu, Pb, Tl, and Zn in paddy soil irrigated with untreated leachate from the tailings retention pond were investigated. As, Cr, Cu, and Zn were slightly contaminated in the surface soil and hence their vertical distribution was not obvious. However, Cd and Pb were highly contaminated in the surface soil, while their concentrations decreased with depth, being negatively correlated with pH and positively with total organic matter. Tl was considerably contaminated in the surface soil and a V-shaped vertical distribution was observed where the concentration increased to a maximum at about 30 cm depth and decreased thereafter. The findings revealed that the regular irrigation with untreated leachate from the tailings retention ponds could cause considerable contamination of Cd, Pb, and Tl, and thus tailings should be stringently treated before disposal to minimize their potential environmental impacts on the surroundings.  相似文献   
18.
Alfalfa is the major forage crop produced in temperate regions worlwide. Although this crop is currently used mainly for producing high-value livestock feed, its application for bioenergy production is a recent focus of interest. Even though it is not mandatory, alfalfa is normally dried in order to improve the quality of the final product. In this study, Life Cycle Assessment (LCA) was used to quantify the environmental impacts linked to alfalfa production in the major cultivation zone in Spain (Ebro Valley), including field activities, dehydration and transport to farms for livestock feeding. In addition, the identification of the most relevant processes contributing to the environmental impact and the potential improvements actions were also defined as objectives. Inventory data were obtained mainly from interviews with farmers complemented with published literature and comments from experts.LCA results were obtained for global warming, acidification, eutrophication, photochemical oxidant formation, land use, non-renewable cumulative energy demand and human, terrestrial and aquatic ecotoxicities. Within the life cycle of alfalfa, the dehydration process, production of phosphate fertilizer, application of nitrogen fertilizers and pesticides, water consumption and final transport to the consumer (by road and ship) were identified as hot spots. Based on these, some improvement measures were proposed and evaluated: (i) reduction of the moisture content of alfalfa and the use of a higher percentage of biomass for combustion in the dehydration process, (ii) no application of nitrogen fertilizer in maintenance years and (iii) use of more efficient trucks for transport. Their implementation would produce significant reduction of eutrophication, global warming, acidification, non-renewable cumulative energy demand and, to a lesser extent, photochemical oxidation formation and human toxicity impacts.  相似文献   
19.
Wild sunflower, H. annuus ssp. annuus, is an invasive species widely distributed in several regions of the world, including central Argentina where it shares a large area with domesticated sunflower. The discovery of imidazolinone resistance in a wild sunflower population allowed the development of Clearfield® technology in cultivated sunflower. This technology was rapidly adopted in Argentina but the trait could possibly be transferred to the naturalized wild populations through natural hybridization. The aim of this study was to evaluate the transfer of IMI resistance to wild sunflower populations and its effect on wild plants’ fitness. Plants of five wild populations and their progenies of crosses with an IMI-resistant hybrid were evaluated through a dormancy, herbicide resistance, and SSR markers study. Relative fitness was compared in the five populations, F1s and backcrosses with wild and crop parental plants. Hybridization with an IMI-resistant hybrid did not alter seed dormancy. F1 individuals were more resistant to imazapyr than their wild ancestors but less tolerant than the commercial variety. SSR markers confirmed the transfer of resistance and identified resistant plants within the wild populations. Fitness was reduced in the first generation after crossing but was recovered in the following generations. Thus, to ensure durability and efficiency of Clearfield® technology, management practices like crop rotation and herbicide usage with different modes of action should be considered.  相似文献   
20.
Environment, Development and Sustainability - A developing country that does not have adequate energy solutions in non-interconnected zones (ZNIs) undoubtedly experiences adverse effects in terms...  相似文献   
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