构建农民收入增长的长效机制

“三农问题”是关系国家经济和社会发展全局的问题，其核心是农民收入增长，农民收入增长的关键是构建收入增长的长效机制。本文通过分析中国农民收入的现状，从制度视角分析农民收入增长缓慢的土地制度、税费制度、金融体制、公共品供给体制以硬社会保障制度等方面原因．在此基础上提出构建中国农民收入增长长效机制的制度框架。     

江西省兴国县土壤侵蚀动态监测研究

介绍发应用遥感技术和调查资料编制的江西省兴国县三个时期（１９５８，１９７５，１９８８年）的土壤侵蚀动态监测图。结果表明，建国以来，该县水土流失的动态变化基本上呈抛物线的态势发展，目前水土流失面积在缩小，程度在降低，总的趋势向好的方向发展。     

Forest Monitoring in Urbanized Areas

Long-term stationary investigations in permanent plots have been performed in forests of different types growing in Greater Moscow. Their results have made it possible to reveal the trends essential to the dynamics of these forests and make a prognosis of their condition in the near future. Moreover, they suggest that it is necessary to review some long-standing concepts concerning the processes of forest formation, relationships between the main forest species, etc.     

ESTIMATING CENTRAL TENDENCY FROM UNCENSORED TRACE LEVEL MEASUREMENTS1

ABSTRACT: The statistical analysis of data which have trace level measurements has traditionally been a two-step process in which data are first censored using criteria based on measurement precision, and then analyzed with statistical methods for censored data. The process might be more informative if data were left uncensored. In this paper, information loss attributable to censoring and measurement noise are assessed by comparing the sample mean and median of uncensored measurements with a log regression mean and median based on censored data. Measurements are derived from lognormal parent distributions which have random variability characteristic of trace level measurement. The relative performance of estimators used with error-free samples and with samples having measurement noise can be explained by differences between the probability distributions of parents and measurements. Measurement introduces bias and dispersion and transforms lognormal parent distributions toward greater symmetry. Estimates using uncensored data are less biased and more accurate than the log regression mean and median when censoring exceeds about 50 percent, and are not much worse at any fraction censored. For data with many (80 percent) results below the limit of detection, bias may be quite severe.     

Monitoring the progress of attempts to reduce nutrient load and inputs of certain compounds in the north sea by 50%

During the winter period an inverse linear relation is found between the concentration of dissolved nutrients (phosphorus and nitrogen) and salinity in the Dutch coastal zone. This indicates a conservative behavior of these compounds from the river, through the estuary to the sea. During summer this relation is much more scattered because of biological processes. The physical and statistical properties of the relationship between salinity and the concentration of dissolved inorganic phosphorus and nitrogen are used to calculate when, where, and how many samples have to be taken in order to monitor a reduction of a compound accurately. It appeared that at any given salinity in the estuary and in the sea, the winter period is the most suitable season to detect a reduction of a given dissolved compound. The higher the salinity in the estuary, the more samples are required to prove the reduction significantly. A reduction of only 10% cannot even be demonstrated by field measurements during summer at salinities above 25. It is concluded that one cruise from the river to the sea, covering the salinities from 0 to 35 during the winter period, aimed at establishing the relationship between the concentration and salinity by taking samples at a salinity interval of for instance 1%, is sufficient to monitor a wide-ranging reduction of 10%–50% in both the fresh water and marine water. This program must be combined with a sampling at a salinity of 0, directed to determine the riverine temporal variability.     

用实测资料对山区逆温的分析

利用云南早期温度层结探空实测资料对山区逆温的特征进行了分析,结果表明:干季逆温出现频率高,山区逆温维持时间长,逆温主要发生在低层。并对同一区域内代表不同下垫面的山区与河谷同期探空资料作了逆温层结的对比分析。     

国外环境监测管理的几点经验

从实验室布局,质量保证体系,实验室管理等方面介绍了国外环境监测管理的几点经验.     

工业污染源废水监测采样方法的改进

介绍了一种新型便携式采样器ＩＳＣＯ３７００，改进了手工采样方法，提高了污染源废水监测的质量。     

浅析室内环境污染检测与控制

分析了室内环境污染的由来、危害及内容,提出了对室内环境污染进行检测与控制,指出对室内环境污染的一些防治对策,表明室内空气污染必将引起广泛的关注和重视.