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181.
In this paper the counteractive dynamic marine and river environments responsible for a river mouth’s and a delta’s modulation is studied. The Acheloos River (West Greece) was chosen as the case study due to the recent changes taken place in its basin. The aim of this study is to analyze the present dominant environment and the impact of human activity on this balance. A GIS database was developed and updated in order to provide access for future use and computer analysis (both spatial and chronological). The study, includes an estimation of the delta forming processes, the impact of the anthropogenic parameters on these processes, and, finally, their representation.  相似文献   
182.
Thirty cases of cervical cystic hygroma were diagnosed in the first trimester of pregnancy. Karyotype analysis was available in 29 (97 per cent). Fifteen (52 per cent) had a chromosomal abnormality. The ultrasound appearance was described as posterior cervical, lateral cervical, or cervical hygroma with hydrops. Of the 14 euploid embryos, six were electively aborted, two are undelivered, and six have been delivered as phenotypically normal infants. In cases in which the chromosomes were normal and the pregnancy continued, all lesions resolved by 18 weeks.  相似文献   
183.
Energy transduction in membrane systems   总被引:3,自引:0,他引:3  
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184.
The recent Green Paper ‘War on Waste’ urges local authorities to organize the recovery and re-use of waste materials in their areas. It is ambiguous, however, on the question of whether recovery should be regarded primarily as a commercial venture or a social service. In this article some of the factors to be considered before embarking on a recovery programme are discussed, and the authors identify some of the arguments for and against the view that recovery is properly a local authority service. Questions considered include the costs and savings associated with a recovery scheme, the impact of the activities of opportunists and the role of the private contractor and voluntary organizations.  相似文献   
185.
Impact of land use on soluble organic nitrogen in soil   总被引:1,自引:0,他引:1  
Although it has been hypothesized that soluble organic nitrogen (SON) plays a central role in regulating productivity in some terrestrial ecosystems, the factors controlling the size of the SON pool in soil remain poorly understood. Therefore our principal aim in this work was to assess the impact of seven different land use systems (rough and managed grassland, deciduous and coniferous woodland, heathland, wetland and tilled land) on the size of the SON and inorganic N (NO? 3, NH+ 4) pools in the surface soil layer (0–15 cm). After extraction with deionised water, we found that in most cases the size of the water extractable organic N (WEON) pool was similar in size to the inorganic N pool. In contrast, the KCl extractable organic N (KClEON) pool constituted the dominant form of soluble N in soils under all land uses, perhaps indicating that significant amounts were held on the soil exchange phase. In contrast to inorganic N, which varied significantly with land use, the size of the KClEON and WEON pool was similar for all land uses with the exception of KClEON in tilled land, where significantly lower amounts were observed. We conclude that SON constitutes an important soil N pool in a broad range of land uses, and that its role in microbial N assimilation, plant nutrition and ecosystem responses to atmospheric N deposition warrants further attention.  相似文献   
186.
Green RH 《Disasters》2000,24(4):343-362
Rehabilitation after armed conflict is a direct intellectual descendant of thinking about rehabilitation after natural calamity. It is related, generally, to poverty reduction and, operationally, to associated action at the micro level. This history has limited its strategic conceptualisation and, in particular, its links with reconciliation and state re-legitimation and also with macro-economic stabilisation and renewed growth. In post-war--or more generally, a lull in conflict with the potential to become permanent--a country's rapid, focused, prioritised action within a strategic framework is urgent. It is not risk-free for political and natural disasters as well as for those with economic and social bases. Flexibility, learning from initial experience and asking intended household beneficiaries about their needs in advance can reduce risk as can pre-positioning of contingency or standby resources to avert post-war calamities (for example, drought, flood) and catastrophes (renewed violence) from delaying and discrediting rehabilitation efforts.  相似文献   
187.
Allophanic soils are widespread around the world, but little research has been done on their transport properties. This study reveals the effect of two soil water potential heads and two water-flow regimes of continuous and intermittent flow on solute transport through undisturbed soil columns of Horotiu silt loam (Typic Hapludand), an allophanic soil. Two different methods--breakthrough curves (BTCs) and time domain reflectometry (TDR)--were employed to determine the extent of preferential solute transport in the topsoil. The TDR data were also used to look at the depth dependence of the transport properties. The convection-dispersion equation (CDE) with the appropriate boundary conditions adequately described the movement of both Br and Cl under the various flow conditions. Although no preferential flow was found under the imposed unsaturated flow conditions, the flow of water and transport of solute became more uniform with depth. The results show that both Br and Cl are retarded in this allophanic soil. Retardation values range from 1.5 to 1.9, and, as the TDR data showed, increase from the depth of 5.0 to 10.0 cm. Intermittent leaching results showed that there was no effect on solute concentrations in the leachate following no-flow periods. This suggests that water and solute transport in this soil were either relatively uniform or that transverse mixing during flow was already fast enough to eliminate concentration gradients between regions of different "mobility."  相似文献   
188.
A case is reported of a male fetus at risk of X-linked adrenoleucodystrophy who showed a normal cultured chorionic villus cell very long chain fatty acid (VLCFA) profile but at birth exhibited grossly abnormal plasma and cultured fibroblast VLCFAs. Maternal contamination or a sample mix-up was excluded by chromosome analysis and analysis of polymorphic markers. This is the second report of a fetus affected with this disorder who showed normal cultured chorionic villus cell VLCFAs. It highlights the importance of a proper audit of all prenatal diagnoses to evaluate method reliability.  相似文献   
189.
林瑾 《福建环境》2003,20(3):52-54
分析了我国在废电池回收利用与管理方面的现状及存在的问题,并结合我国国情提出实现废电池循环再利用的对策。  相似文献   
190.
An assessment of floodplain regulation by the Upper Thames River Conservation Authority in the City of London for the period 1978–1989 was undertaken. Utilizing a mix of data sources available through the conservation authority office, questionnaires administered to flooplain residents, interviews with relevant government officials, and housing statistics, the study concludes that regulations have been administered in an equitable and efficient manner. However, regulations have had some problems in controlling all development activity and in addressing policy objectives. Problems arise from weaknesses in the Conservation Authorities Act, an ensuing lack of judicial and participating municipal support in prosecuting violations, and inadequate monitoring and enforcement of development activity. Without addressing these issues, the basic problems associated with floodplain management in Ontario will remain.  相似文献   
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