地理信息系统支持下的中国耕地面积空间变化研究

本文以１９８５年与１９９４年我国各县粮食生产统计数据为依据,运用地理信息（ＧＩＳ）为分析手段;从空间变化特征、变化成因及变化趋势三个方面,着重对１９８４年以来我国耕地面积的空间变化进行了定量研究。     

A Knowledge-Based Systems Approach to Design of Spatial Decision Support Systems for Environmental Management

/ This paper describes a framework for designing spatial decision support systems for environmental management using a knowledge-based systems approach. An architecture for knowledge-based spatial decision supportsystems (KBSDSS) is presented that integrates knowledge-based systems with geographical information systems (GIS) and other problem-solving techniques. A method based on spatial influence diagrams is developed for representation of environmental problems. The spatial influence diagram provides an interface through which knowledge-based systems techniques can be applied to build capabilities for problem formulation, automated design, and execution of a solution process. In addition to the flexibility and developmental advantages of knowledge-based systems, the KBSDSS incorporates expert knowledge to provide assistance for structuring spatial influence diagrams and executing a solution process that automatically integrates the GIS, data base, knowledge base, and different types of models. The framework is illustrated with a system, known as the Islay Land Use Decision Support System (ILUDSS), designed to assist planners in strategic planning of land use for the development of the island of Islay, off the west coast of Scotland.KEY WORDS: Geographical information systems; Spatial decision support systems; Knowledge-based systems; Spatial influence diagrams; Environmental management     

Fragile X demonstrated retrospectively in amniotic cells cultured in low folate medium

Chromosome analysis in a boy aged 10 months, with psychomotor retardation, revealed the fragile X-chromosome in lymphocytes and skin fibroblasts cultured in low folate medium (TC 199). Amniocentesis and chromosomal analysis had been carried out during pregnancy because of advanced maternal age. Review of the slides from amniotic fluid cells grown routinely in low folate medium showed the marker X in 10.6 per cent of the metaphases. Possible explanations for the appearance of the marker X in amniotic cell culture are discussed.     

Prenatal diagnosis of adult polycystic kidney disease with DNA markers on chromosome 16 and the genetic heterogeneity problem

A prenatal diagnosis of adult polycystic kidney disease by DNA testing is reported. Evidence showing a linkage between the disease and the 3′HVR and 24.1 restriction fragment length polymorphisms (RFLPs) on chromosome 16 was obtained in the proband's family by linkage analysis of data and homogeneity testing with Italian families of the linked type. Fetal genotype prediction based on both flanking markers was confirmed by histological and ultrastructural findings in fetal kidneys.     

油藏地球化学研究的理论基础与发展趋势

油藏地球化学是一个新兴的地球化学分支学科,是传统的有机和无机地球化学与油藏工程紧密结合的产物。其产生对油气勘探和开发起着重要的作用。本文从油藏非均质性、充注史和流体-岩石相互作用三个方面论述了油藏地球化学研究的理论基础,并简要总结了油藏地球化学近年来的长足发展以及产生的一些新兴研究内容。     

Human impact on current environmental state in Chinese lakes

Anthropogenic and natural disturbance to inland aquatic ecosystems displays a notable spatial difference, yet data to measure these differences are scarce. This study encompasses 217 lakes distributed over five lake regions of China and elucidates the environmental factors determining the spatial variability of the water quality and trophic status. A significant correlation between human modification index in surrounding terrestrial systems (HMT) and trophic status of lake ecosystems (TSI) was found, and the regression slope in each region was similar except in the Qinghai-Tibet Plateau region. It was further noted that the pattern of environmental factor network (EF network) differed among freshwater and saline lakes. The EF network was complex for freshwater lakes in less human-influenced areas, but intensive man-made influence disrupted most relationships except for those between total nitrogen, total phosphorus, chlorophyll-a, and water turbidity. As for regions including saline lakes, correlations among water salinity and organic forms of carbon and nitrogen were apparent. Our results suggest that HMT and EF network can be useful indicators of the ecological integrity of local lake ecosystems, and integrating spatial information on a large scale provides conservation planners the option for evaluating the potential risk on inland aquatic systems.     

油藏分隔性的地球化学研究

油藏的分隔性和油层连通性研究为油气成评价的重要内容，当前，油藏描述技术已经成为研究油层连通性的重要手段，但常规的油藏描述只着眼于储层的非均质性，主要研究储层的空间分布规律及其对油层连通性的影响。油藏地球化学研究成果表明，砂层连通体不一定等同于流体选通体，因为油层内可能存在有机隔层，出现“低层连通，油层分隔”的现象，利用地球化学方法可以直接研究油藏内部流体的非均质性，有效地判断油藏的分隔性。本文介绍了应用地球化学方法研究油藏分隔性的理论依据和研究方法，并介绍了几个北海油田的研究实例。     

Multifunctional landscapes--perspectives for the future

New methods in landscape ecology to study the link between landscape between landscape heterogeneity and landscape functionality are needed.Heterogeneity is a basic characteristic of Iandscape,and landscape fnction is the capacity to change the structural heterogeneity of a landscape ystem.In most developed countries the industrialisation of agriculture has in general resulted in a change of agricultural landscapes from a small-grained heterogeneous pattern towards more monotonous and monofunctional landscapes.During the 1990‘s this trends seems to have changed due to a diversification of rural land use and new trends in urbanisation.Weather these phases of landscape development should be expected in developing countries is a totally open question.Dealing with the study of multifunctionality of landscapes it is proposed to distinguish between ecological functionality of landscape ecosystems,functionality.Further,the relation between function,space and scale is important by the determination of spatial and time segregation as well as spatial and time integration of multifunctionality in landscapes.     

Species-specific antipredator capacities and prey refuges: interactions between piscivorous perch (Perca fluviatilis) and juvenile perch and roach (Rutilus rutilus)

The outcome of predator-prey interactions depends on the characteristics of predators and prey as well as the structure of the environment. In a replicated field enclosure experiment, we tested the effects of quantity and quality of different prey refuges (no structure, structure forming a partial refuge, and structure forming a complete refuge) on the interaction between piscivorous perch (Perca fluviatilis) and juvenile perch and roach (Rutilus rutilus). We quantified the behaviour of the predators and the prey and predator-induced prey mortality. The piscivores stayed in or close to the prey refuge and were more dispersed in the presence than in the absence of prey refuges. Survival of juvenile perch and roach decreased in the presence of predators and was higher for juvenile roach than for juvenile perch. In addition, juvenile perch survival increased with refuge efficiency Roach formed schools which were denser in the presence of predators, had a higher swimming speed (both in the open water and in the refuge) and used a larger area than juvenile perch. Both prey species decreased their distance to the prey refuge and increased the proportion of their time spent in the refuge in the presence of predators. The number of switches between the open-water habitat and the prey refuge was higher for juvenile roach than for juvenile perch. Juvenile perch used different parts of the prey refuge in a flexible way depending both on presence of predators and refuge type whereas juvenile roach used the different parts of the prey refuge in fixed proportions over all refuge treatments. Our results suggest that juvenile roach had a overall higher capacity to avoid predation than juvenile perch. However, in the presence of qualitatively different prey refuges juvenile perch responded to predators with more flexible refuge use than juvenile roach. The differences in antipredator capacities of juvenile perch and roach when subjected to piscivorous perch predation may depend on differences in life history patterns of the two species.