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971.
There exist a vast variety of data sources, either manual sources or computerized databases in the field of environmental chemicals. To facilitate the access and to retrieve the information wanted efficiently, we built up two “databanks of data sources”, one called “Databank of Manual Sources (DMAS)” and the other named “Databank of Databases (DADB)”. The set‐up of these databanks is explained and the load status statistics are shown. DMAS has 164 and DADB 106 hits.  相似文献   
972.
Simplified models provided information on the binding ability of organic acids with trace elements, the distribution of the formed organo‐heavy metal complexes at different pH, and the biological stability (biodegradation ability) of these complexes.  相似文献   
973.
The water leaching of diazinon (O,O‐diethyl‐O‐2‐isopropyl‐6‐methylpyrirnidin‐4‐yl phosphoroth‐ioate) through soil columns, was studied after column amendments with two well characterized humic acids (HA), in both liquid and solid state, and with the original raw organic materials, an oxidized coal and a leonardite, from which the HA were extracted. The percolation curves and the pesticide distribution over the soil columns showed that the addition of the raw organic materials and the solid HAs reduced significantly the mobility of the pesticide along the soil column. The oxidized coal was more effective than the leonardite original material; the different origin of the two carbon‐rich materials had an influence on the diazinon movement along the soil columns and such difference was enhanced with increasing addition rates. Moreover, incubation at field capacity for two months of the soil columns treated with raw oxidized coal and leonardite, largely enhanced the described effects on pesticide behaviour. A complete adsorption of diazinon on columns and a practical absence of leaching was observed when the HA from both materials were added in dissolved form. These results were explained with the swelling of the humic micelles in water and the enhanced availability of inner hydrophobic surfaces for the strong adsorption of diazinon. The water diffusion into the solid humic materials after two months incubation, also explains their high pesticide retention capacity. This work indicates the usefulness of either solid o dissolved humic substances, with the proper hydrophobic character, in preventing the vertical leaching of non‐polar organic pesticides in soils.  相似文献   
974.
The European INventory of Existing commercial Chemical Substances (EINECS) lists all substances which were on the European Community Market between 1 January 1971 and 18 September 1981. Substances on EINECS are known as ‘existing’ substances. The EINECS inventory was drawn up by the European Commission to meet the requirements of article 13 of Directive 79/831/EEC [1]. EINECS was published in the Official Journal of the European Communities in 1990 [2]. This paper describes how individual substances, impurities and mixtures were defined and dealt with when registered for the EINECS inventory. It is the first in a series of such papers.  相似文献   
975.
In most protected areas of the Indian Himalayan region site/habitat characteristics, community diversity and distribution pattern, vegetation composition (richness of native and endemic species), structural patterns, economic importance of forest communities and community priorities have rarely been studied. Therefore, the present study has focused on these in the buffer zone of Nanda Devi Biosphere Reserve. Seventy-six woody species (trees: 24; shrubs: 52) and 13 forest communities have been recorded between 2300–3800 m asl. Tree density ranged from 533–1220 ind ha-1, tree basal area from 14.68-80.28 m2ha-1 and shrub density from 1490–6695 ind ha-1. Mean density of trees was significantly lower in temperate forests in comparison to subalpine forests. Richness of trees ranged from 3–18 and shrubs from 5–29. Species diversity (H') of trees ranged from 0.45-2.08 and shrubs from 0.90-3.14. In the temperate zone, species richness and altitude had significant positive correlations whereas in the subalpine zone the two variables were negatively correlated. The native species were high in the area (> 65% species) and in communities (> 70% species), and was highest for the Picea smithiana-Pinus wallichiana mixed community, whereas the maximum numbers of natives and endemic species were recorded in the Pinus wallichiana community. The density and richness of non-natives were found to be significantly lower in comparison to the natives. Economic importance and conservation value of the communities were assessed and communities prioritized. Monitoring of the identified habitats, species, populations and communities, and development of appropriate strategies for their conservation and management are suggested.  相似文献   
976.
SUMMARY

Rainfall-surface water runoff relationships have been examined for 912 rainfall events during the 1992 and 1993 monsoon seasons on 15 erosion plots on a variety of non-cultivated land uses in the Middle Hills, Nepal. Vegetation cover and type examined ranged from grassland and relatively undisturbed mixed broadleaf forest to subtropical Sal forest, in various states of degradation, and bare ground. Runoff was frequently generated on most plots and often by relatively small rainfall amounts (less than 5 mm) and low rainfall intensities (3 mm/h). Ground cover and canopy cover were significant factors in determining amounts of runoff. Runoff coefficients ranged from 1–2% under grassland and mixed broadleaf forest to 57–64% on the bare sites. Coefficients for Sal forest were between these two extremes; specific values depended on the level of degradation induced by human activity. The most degraded forest sites experienced runoff coefficients of 33%. Ground cover beneath the trees, especially leaf litter, was more effective in reducing runoff than the amount of canopy cover. Canopy cover was more effective during the less intense storms but was ineffective when the rainfall intensity was high. The results suggest that a minimum ground cover of 60% will keep runoff to within 10% of total rainfall amounts for most normal monsoons in the Middle Hills. This will also reduce the risk of gullying and surface soil erosion. It is the nature of the forest that is important and not its total area. In the study area, although the total area under forest had not changed, some of the forest had become more degraded with a corresponding increase in mean runoff rates. Increased runoff can occur even if the area under forest increases. Estimates of levels of degradation based solely on changing forest areas are likely to be inaccurate.  相似文献   
977.
This paper demonstrates a correlation between the extensiveness of infrastructure and national development. This was achieved by considering kilometres of paved roads, kilometres of rail, kilometres of paved runways, quality of shipping ports and quality of urban infrastructure. Data were collected from a variety of sources including the World Bank and the United Nations databases. Measures of the quantity or extensiveness of the infrastructures were normalized based on the populations of the various countries, transforming them into per capita measures, which were then logarithmically transformed to produce indices of the extensiveness of the infrastructures. These indices were then plotted against the national development indicator, the human development index (HDI). Of the infrastructures considered, paved roads per capita index showed the strongest correlation with HDI, while quality of port infrastructure index showed the weakest correlation. When the indices for the different infrastructures were combined into a single index the correlation with HDI appeared to be strongest, highlighting the synergistic effect of different infrastructures when working in tandem. Based on this, the findings of this study support the position of holistically managing a country's infrastructure assets.  相似文献   
978.
This paper presents the status of sustainable livelihood security index (SLSI) of Karnataka, the most drought prone state in the Southern part of India. Computation of ecological security index, economic efficiency index and social equity index, and finally SLSI were carried out at the district level for the entire state, using empirical data. The selected indicators were first normalised, and then using estimated weights, indices were computed. The results indicate that the state has a very low SLSI with only 27.6% of total geographical area (TGA) and 21.7% of population being placed in the ‘sustainable’ and ‘highly sustainable’ categories (covering 10 districts) while only 34% of the TGA covering six districts falls in the ‘moderately sustainable’ category. The remaining area, confined mostly to the northern parts of the state, comprising 14 districts (51.8% of the state’s TGA) is categorised as ‘less sustainable’ and ‘very less sustainable’ exposing 44.4% (27.14 million) of state’s population to the perils of uncertain rainfall, high soil erosion rates, high social inequality and poor resource use efficiency. There is an urgent need to reorient development programmes and prioritise development investments in these vulnerable districts so that they are provided resources and opportunities to improve their ecological (more forest cover and less soil erosion), economic (higher agricultural productivity) and social (improved health and education facilities and rural infrastructure) status and achieve sustainable levels of livelihood.  相似文献   
979.
SUMMARY

Sustainable development has become the conceptual framework within which societal, economic and environmental issues are addressed at every level around the world. In 1993, a United States-Canada assembly of more than 250 Great Lakes leaders was convened to evaluate the efficacy of creative processes under way in the Great Lakes Basin relative to sustainable development and to identify key success factors and process characteristics which are consistent with principles of sustainable development. A combination of eight criteria for effective project management (i.e. stakeholder involvement; leadership; information and interpretation; planning; human resource development; results and indicators; review and feedback; stakeholder satisfaction) and six principles of sustainable development (i.e. long-range planning and intergenerational responsibility; carrying capacity; anticipation and prevention; full cost accounting; integration of economic, social and environmental factors; efficiency, innovation and continuous improvement) were developed to evaluate and help improve decision-making processes. Such criteria and principles may be useful in improving decision-making processes in other parts of the world.  相似文献   
980.
In order to determine the role of termites in the recycling of organic matter and in humification processes, organic matter from the mound of a wood-feeding termite (Nasutitermes sp.) and from the litter directly below has been studied in secondary forest on the campus of Belem University, in Brazil. The carbon content was slightly lower in the litter (just beneath the mound) than in the mound, but nitrogen was much more abundant in the mound. As a consequence, the C/N ratio of fragmented litter total organic matter is very high, which shows that the humification process is not complete. Therefore, plant debris seemed to be more degraded in the mound than in the litter, indicating a humification gradient from mound to litter. Humic acid extracted from the mound and from the litter was compared by using elemental, E4/E6 ratio, spectroscopic (FTIR) analyses, and Sephadex gel chromatography. First, humic acids were more abundant in the mound than in the litter, showing that humification processes were more advanced in the mound than in the litter. Gel-permeation chromatography showed that the humic acids of the mound contained more low-molecular-weight fractions than those of the litter. In addition, the results of infrared spectra, E4/E6 ratio and elemental composition can confirm the fulvic character of mound material and the humic character of litter material. Therefore, the plant debris seems to follow two different humification pathways in the two environments, as long as the mound is alive.  相似文献   
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