A Variance Estimator for Constrained Estimates of Change in Relative Categorical Frequencies

Consistent estimators of change and state becomes an issue when sample data come from a mix of permanent and temporary observation units. A joint maximum likelihood estimator of state and change creates estimates of state that depend on antecedent viz. posterior survey results and may differ from estimates of state derived from a single-date analysis of the sample data. A constrained estimator of change in relative categorical frequencies that eliminates this potential inconsistency is proposed and a model based estimator of their sampling variance is developed. The performance of the constrained estimator is quantified against six criteria and a joint maximum likelihood estimator in simulated sampling from 15 populations with three combinations of permanent and temporary samples, four to six categorical class attributes, and constant size between sampling dates. Bias of the constrained estimators was negligible but larger than for joint maximum likelihood estimators. Mean absolute deviations and variances of constrained estimators were generally at par with the joint estimators. Constrained estimators of root mean square errors and achieved coverage of nominal confidence intervals of constrained estimators were occasionally better. A generalized variance function for the constrained estimates of change is provided as a computational shortcut.     

雨天硫酸盐化速率样品扩散分析

选择采样期不同降雨天数的碱片，测定余边的硫酸盐化速率含量，其结果为：采样期全月无雨时，余边上的硫酸盐均未检出；半月以上至全月有雨时检出率为１００％，检出量占样品量的２．７０～１５．９５％。经扩散试验，查清了余边上的硫酸盐主要是有效面积上采集的样品的扩散，并提出了相应的修正方法。     

The Variability of Estimates of Variance, and Its Effect on Power Analysis in Monitoring Design

Power analysis can be a valuable aid in the design of monitoringprograms. It requires an estimate of variance, which may come from a pilot study or an existing study in a similar habitat. For marine benthic infauna, natural variation in abundances canbe considerable, raising the question of reliability of varianceestimates. We used two existing monitoring programs to generatemultiple estimates of variance. These estimates were found to differ from nominated best estimates by 50% or more in 43% of cases, in turn leading to under or over-estimation of samplesize in the design of a notional monitoring program. The twostudies, from the same general area, using the same samplingmethods and spanning a similar time scale, gave estimatesvarying by more than an order of magnitude for 25% of taxa.We suggest that pilot studies for ecological monitoring programsof marine infauna should include at least two sampling times.     

红壤中结合态磷在酸化条件下的变化及其相互关系

以浙江沿海地区的红壤为研究对象，通过浸滤过程，研究了在酸化条件下，红壤中可溶笥结合态磷的变化和它们之间的相关关系，结果显示，红壤中可溶性Fe-P比Ca－P、Al－P对酸度的变化更为敏感；当红壤中可溶性磷的原始含量较高时，随酸度的增强从固相中释出的趋势更明显；在酸化过程中、红壤中不同可溶性结合态磷之间呈现出不同的相关关系，这归因子它们对酸化敏感性的差异。     

岩溶山区雨水资源有效利用研究——以贵州省普定县马官地下水库为例

以贵州省普定县马官地下水库为例,从区域岩溶地质概况、成库条件、库容分析和降雨量及补给量计算、工程效益等方面,对马官地下水库进行了研究,阐述了马官地下水库是岩溶山区雨水资源有效开发利用的典型,具有推广意义。     

渗滤液回灌对填埋垃圾含水率的影响研究

文章通过模拟实验研究了不同的渗滤液回灌频率、回灌量和回灌速率对压实密度不同的垃圾的含水率的影响。研究表明,由于通道流的存在和影响,渗滤液的产生时间提前于填埋垃圾达到其有效贮水率的时间;渗滤液回灌频率越高、回灌量越大、回灌速率越慢、垃圾体温度越低、垃圾压实密度越高,则填埋垃圾的有效贮水率越大、含水率越高。在实施渗滤液回灌操作时,须综合考虑滤液回灌频率、回灌量、回灌速率、垃圾温度和垃圾压实密度等影响因素。     

开展环境审计是邯郸市经济可持续发展的有效途径

随着邯郸市经济高速增长、人口数量增多、城市化进程加快及公众环境要求的提高,经济社会高速发展与资源能源短缺的矛盾、城市化进程加快与城市基础设施建设滞后的矛盾、公众环境要求提高与环境保护能力相对薄弱的矛盾将集中爆发.环境审计作为环境管理的现代方法之一,对于节约和有效利用资源,加快邯郸市产业结构调整步伐,合理配置各种生产要素,促进经济可持续发展具有重要的作用和意义.开展环境审计是审计工作发挥监督职能作用,促进经济走向可持续发展道路的有效途径.     

涡凹气浮机在炼油污水处理中的应用

对涡凹气浮机在炼油污水气浮工艺的改造的应用进行了总结，改造后该气浮机具有投资省、运行费用低、操作维护简单、工作效率高等优点，且运行稳定，效果比较理想，应用前景十分广阔。     

11种有机磷农药对海洋微藻致毒效应的研究

通过研究不同盐度条件下１１种有机磷农药对扁藻的相对增长率和叶绿素ａ含量的影响，得到了Ｓ＝３０和Ｓ＝２０时的半数有效浓度，并比较其大小。盐度作为环境因子，影响到有机磷农药的毒性。研究发现，遥有机磷农药在低浓度时出现一定限度的促生长作用；容易进攻细胞膜的有机磷农药对扁藻的致毒性相对较强；此外，有机磷农药的毒性大小与其结构密切相关含有苯环结构的有机磷农药毒性大小不含有苯 有机磷农药的毒性。     

污水处理的新技术与新发展

介绍我国对水污染控制认识的发展和深化，阐述了污水生物处理方面的研究和新进展，包括在微生物方面的研究和新反应器、新工艺的发展。同时，讨论了新型、高效化学混凝剂和絮凝剂的开发成功，使化学法用于城市污水的处理成为可能。并提出任何一种新的处理工艺和反应器都各有其优缺点和适用条件，不能认为某一种就是最好，最先进的，可以无条件适用各种情况的。