Designing and integrating composite networks for monitoring multivariate gaussian pollution fields

Networks of ambient monitoring stations are used to monitor environmental pollution fields such as those for acid rain and air pollution. Such stations provide regular measurements of pollutant concentrations. The networks are established for a variety of purposes at various times so often several stations measuring different subsets of pollutant concentrations can be found in compact geographical regions. The problem of statistically combining these disparate information sources into a single 'network' then arises. Capitalizing on the efficiencies so achieved can then lead to the secondary problem of extending this network. The subject of this paper is a set of 31 air pollution monitoring stations in southern Ontario. Each of these regularly measures a particular subset of ionic sulphate, sulphite, nitrite and ozone. However, this subset varies from station to station. For example only two stations measure all four. Some measure just one. We describe a Bayesian framework for integrating the measurements of these stations to yield a spatial predictive distribution for unmonitored sites and unmeasured concentrations at existing stations. Furthermore we show how this network can be extended by using an entropy maximization criterion. The methods assume that the multivariate response field being measured has a joint Gaussian distribution conditional on its mean and covariance function. A conjugate prior is used for these parameters, some of its hyperparameters being fitted empirically.     

东部发达地区应加速农村人口城市化——上海市郊区农村加速城市化问题研究

在生产力迅速发展 ,经济结构发生显著变化的新形势下 ,东部发达地区应高度重视加速推进农村人口城市化的问题。论文以农村生产力处于全国领先水平的上海市郊区为例 ,对与加速农村人口城市化相关的若干问题进行了探讨 ,指出近年来上海郊区农村社会经济包括城市化虽已取得很大发展 ,但城市化仍明显滞后于工业化和非农化 ,城镇的人口规模偏小、“分散式集聚”等矛盾也比较突出。论文提出了加速上海郊区农村人口城市化的目标 ,并对其可行性作了论证。在此基础上 ,还对近期迅速推进农村城市化应采取的主要政策措施进行了研讨。     

The Quality of Urban Environments in the Brazilian Amazon

In the Brazilian Amazon during the 1980s,urban population growth outstripped rural growth, andby 1991, most of the region's population resided inurban areas. Much of this urban growth involvedestablishment of unplanned housing with inadequateinfrastructure, which resulted in rising pollution. This paper compares indicators of environmentalquality in urban populations of the Amazon in 1980 and1991, and among different kinds of urban populationsin 1991. The results show that environmental qualityin the region deteriorated during the 1980s as theproduction of and exposure to environmental hazardsrose while resources to ward off hazards eroded. Thefindings also show that environmental quality wasparticularly poor in more rapidly growing urbancenters. The urban Amazon may not afford an adequatestandard of living and this may generate out-migrationfrom the region.     

对广东省流动人口婚育问题的初探

:广东是我国流动人口最多的省份,流动人口的婚育问题也成为研究的热点之一。本文首先对流动人口作了界定,并分析了广东流动人口的特征及其对婚育行为产生的正面和负面影响,这使计划生育管理面临巨大的压力。文章最后提出一些措施以图化解流动人口的婚育问题带给城市的压力     

DNA芯片技术

DNA芯片可用于核酸序列的测定及基因突变检测等,这里对DNA芯片的制作、作用原理、性能及用途等进行了综述。     

21世纪世界人口面临的主要问题与挑战

人类跨入 2 1世纪 ,在迅速发展经济的同时 ,也面临着一些问题和挑战。世界人口数量急剧增长 ,人口倍增时间大为缩短。人口老化速度加快 ,在 2 1世纪的前 10年 ,世界各国都将出现人口老龄化趋势。随着现代化工业和市场经济的飞速发展 ,全球人口城市化速度日益加剧。同时贫困人口问题困扰发展中国家。人类为了满足自身发展的需要 ,导致自身资源日益减少 ,生态环境日益恶化 ,如不设法采取补救措施 ,将会面临一场生态灾难     

世界人口格局中的中国人口转变及其特点

20世纪 50年代以后的中国人口转变与西方传统人口转变有许多不同之处 ,具有自身的特点 ,即转变的迅速性、控制干预性、不彻底性、不稳定性、不平衡性。把握新时期稳定低生育水平的决定是将我国人口转变进行到底的重要措施和手段 ,是实现人口可持续发展的重要步骤     

韩国人口老龄化与老年人社会保障

随着近几十年生育率的持续下降及平均寿命的不断提高 ,韩国人口逐渐出现了老龄化趋势。到下世纪初韩国人口老龄化进程将进一步加快。韩国人口老龄化的显著特征 ,就是在急剧的现代化过程中 ,还没来得及健全老年人社会保障、福利、医疗、保健等制度的情况下将迎来迅速的人口老龄化 ,从而使全社会面临着不断增长的老年人福利、医疗、保健需求     

流动人口计划生育工作指标体系与考核评估方式初探

流动人口计划生育工作是我国计划生育工作的两大难点之一。要提高流动人口计划生育管理水平,必须建立科学的指标体系来规范流动人口计生管理。本文结合实践,论述流动人口计生管理工作指标体系设置原则,统计口径,以及管理质量考核评估方法和内容。     

城市迁移人口及管理问题探讨

改革开放以来中国城市人口增长的最主要来源是人口的迁移增长 ,因此城市人口管理体制的重要一环是城市人口迁移的管理。本文根据城市人口迁移管理体制及其相关的问题进行分析 ,提出了要科学地依据自然资源与社会资源测定城市的人口承载力 ,对人口迁移增长的控制有科学的根据 ,对人口迁移增长有目标、有规划 ,并对城市人口迁移进行科学管理的创见