有关边界层问题中一类奇异积分方程新的存在性结果

对边界层理论新结果中出现的一类奇异积分方程w（t）=∫1 t（1-s）（λ＋λs＋s）/w（s）ds＋（1-t）∫t 0s/w（s）ds,t∈（0,1）进行讨论，并得出了上述方程在λ∈（-1/2,0）上正解存在性的新结果。     

BACKGROUND STUDY ON NON-RESIDUAL PHASE OF ELEMENTS IN CHANGJIANG AND HUANGHE ESTUARINE SEDIMENTS

Analysis of Zn, Cu, Pb, Co, Cr, Li, Ni, K, Al, Fe extracted by 1 mol/L HCl or 0.5 mol/LHCl/H_2O_2, showed concentrations of Zn, Cu, Pb, Co, Cr, Fe, Ni were significantly correlated with Li, Al,K, and clay. Two methods are used to indicate the background value of the non-residual phase of elementsin sediments, and are the same as the methods used to indicate the background value of totalconcentrations in sediments. The first method uses correlograms and regression equations,the second usesthe mean element concentrations normalized with grain size. Li, Al, K can be used as reference elements to determine the background value of Zn, Cu, Pb, Co,Cr, Ni, Fe, while the clay concentration's correlation with some extractable concentrations can be used tocalculate the background value of the non-residual phase of elements as a percentage of clay concentrationin the sediments. Based on this study, the concept of using the background value of the non-residualphase of elements to compare the pollution level in differ     

抗差估计的初值选择

对L1 范估计的平差值和LS估计的平差值作为抗差估计的初值进行了比较 ,指出在 ρ函数是严凸函数时 ,二者无明显的区别。因为LS估计简单且易于计算 ,因此建议用LS估计的平差值作为抗差估计的初值。     

广西河池地区矿产资源勘查成果展销会情况介绍

１９９５年７月１１日—１２日，广西地矿厅和河池地区行署首次联合举办矿产资源勘查成果展销会，会址设在河池市，与会代表１３０余人。展销会提交大会展销的矿产资源勘查成果３８项，引资勘查项目３８项。经买卖双方三天的洽谈，涉及到的项目２５项，会议期间签订矿产资源勘查成果合同协议４项，愈千万元，取得较好的社会经济效益。为地勘资金多渠道来源开辟了新路子，对促进地勘单位地质找矿工作及勘查成果有偿使用发挥了重要作用     

广西芒场锡多金属矿田稳定同位素组成对矿床成因探讨

笔者曾对广西芒场锡多金属矿田的稳定同位素进行研究。本文根据硫、铅、氢、氧、碳等稳定同位素组成和锶的初始值提供的信息.探讨了矿床成因。并结合矿田矿床地质特征、控矿条件及有关统计参数,参考前人对矿床认识的基础上,修正提出了该矿田混合热液成矿模式,可供类似矿床研究和找矿的参考。     

用遗传算法解算病态方程

对应用遗传算法解决病态方程问题进行了探讨。利用拟合法而不是通过法方程求解参数，从而避免了法方程系数求逆，使病态方程的解答有了较好的结果。通过模拟计算并和其他方法进行比较，证明该方法是可行的和有效的。     

THE EVOLUTION OF SERVICE ECONOMIES: A GEOGRAPHICAL PERSPECTIVE1

Of the several classifications of services, each emphasizes different characteristics. The International Standard Industrial Classification (ISIC) is used for a comparative study on the transformation into service economies of the U.S., Canada, Great Britain, France, West Germany, Italy and Japan. Service economies are defined as national economies in which employment in services surpassed that in manufacturing. The pace of the evolution of service economies has been rapid with North America leading, followed in order by Great Britain, France, Italy, Japan and West Germany. Service economies have important implications for urban growth, intercity competition, and international trade.     

Participation in payments for ecosystem services: Case studies from the Lacandon rainforest, Mexico

Understanding people’s willingness to participate in projects and programmes of payments for ecosystem services (PES) has not been a key analytical concern of the scholarly literature around this new field of environmental policy and practice. This paper analyses participation in four communities benefiting from payments for biodiversity and carbon fixation in Mexico, and contrasts the results for each case with neighbouring communities that do not receive payments. We take a holistic approach that accounts for procedural rules, actors’ interactions, institutions and values, and individuals’ characteristics. We show that the nature of PES rules and the effectiveness of communication with government officers and NGOs influence resource managers’ ability and willingness to participate. We highlight community size, resource managers’ ability to diversify livelihood activities and local perspectives on the conservation of common forests, particularly sacred values and intergenerational concerns on forest conservation, as critical participation drivers. This analysis provides insights on why and how these new institutions may be attractive for some resource managers and permits to draw some recommendations for the future design of PES projects and programmes.     

Water and power in Santiago de Chile: Socio-spatial segregation through network integration

The analysis of the history of the management and distribution of electricity, water and sanitation networks in Santiago de Chile throws light on a problem which is central to thinking on the relationship between urban services management and territorial splintering: what is the impact of urban policy, in particular housing policy and urban planning, on access to services and on the potential levels of social segregation and institutional splintering of metropolises?The Chilean example is eminently anchored in its political and institutional history. We shall see, for example, that the authoritarian urban policy of the military government, associated with early liberal reform, enabled the improvement of access to networks in every municipality of the Greater Santiago area. However, this success, leading to the integration by urban services of a large territory, does not signify that networks remained neutral as regards the process of spatial segregation. Inversely, we can defend the theory that the presence of an integrated service was a necessary condition and a reinforcing factor of the process of urban spread and residential segregation. This paradoxical argument is a result of the ambivalent liberal network and urban policies of the military government. Urban expansion was largely sustained by the development of integrated infrastructures and universal services. The processes of liberalising land and urban services were mutually sustaining and provided the necessary conditions for the birth of an extremely intense movement of urban sprawl and segregation between 1985 and 2000.     

Beyond the numbers: Understanding the value of vegetation to rural livelihoods in Africa

Different types of vegetation found in local environments are of value to rural livelihoods of many African households. However, the dominant way of expressing this value, which is mainly through economic valuation studies, is potentially limiting this knowledge’s usefulness in policy and research, due to the inability to present full picture. Using literature review and insights from field work, the paper argues that realized and notional values of vegetation to rural livelihoods are socially constructed and contested, and - in addition to understanding local livelihood context, which include social difference, and ecological dynamics - a focus on social institutions as terrains of negotiation is crucial. This means that resource value in rural livelihoods can be realized through contested and negotiated access arrangements that are mediated by complex institutions at local and external levels.