Line intersect sampling: Ell-shaped transects and multiple intersections

The probability of selecting a population element under line intersect sampling depends on the width of the particle in the direction perpendicular to the transect, as is well known. The consequence of this when using ell-shaped transects rather than straight-line transects are explicated, and modifications that preserve design-unbiasedness of Kaiser's (1983) conditional and unconditional estimators are presented. A case against treating multiple intersections as multiple probabilistic events is argued on the basis, also, of preserving design-unbiased estimation.     

等速采样提高烟尘浓度数据质量

通过对流量计的校准、校准流量的修正和真实流量的推导 ,归纳出等速采样流量的综合算式 ,并运用程序计算法进行快速、准确地计算 ,真正实现等速采样。又通过对采样体积计算公式的重新推导 ,使之更加准确。从而达到提高烟尘浓度数据质量的目的     

Synthesis and application of insect attractants in Vietnam

Detrimental effects of synthetic pesticides on health, environment and organisms have necessitated the exploration of alternative strategies for insect control. The insect attractants represent an important link within these systems. In Vietnam, since 1970, methyleugenol and its analogues have been synthesized for mass trapping of the fruitfly Daccus dorsalis Hendel. This chemical reduced the damage on the oranges of many plantations in our country. In the period 1978–1980, for the first time some selected types of pheromones were tested. The trials verified and provided evidence of the occurrence of six species of moth in southeast Vietnam: Archips micaceanus, Archips seminubilus, Cadra caustella, Spodoptera exigua, Chysodeixis eriosoma and Parapoynx sp. The last decade has seen intense activity in the elaboration and application of some complex systems of fighting plant pests. Pheromones of moth and weevils have been prepared in the Institute of Agrochemistry and the Institute of Tropical Biology NCST: Ostrinia nubilalis Hbn, Heliothis armigera Hbn, Plutella xylostella Curt, Adoxophyes sp, Lyonetia clerckella, Trogoderma granarium, Diabrotica virgifera virgifera, Diabrotica undecimpunctata, Blattela germanica, Diprion, Neodiprion, Scolytus multistriatus, Scolytus scolytus, Lasioderma sericorne, Tribolium cofusum. Some synthetic aspects of these pheromones are described. The use of pheromone traps for monitoring and mass trapping the Scolytus multistriatus, Tribolium confusum, Plutella xylostella Curt, Heliothis armigera Hbn, Cylas formicarius elegantulus will be discussed.     

Prenatal diagnosis of trisomy 20 by chorionic villus sampling (CVS): a case report with long-term outcome

A case of prenatally diagnosed non-mosaic trisomy 20 in cells cultured from a chorionic villus sample (CVS)is presented. The term placental karyotype was also non-mosaic trisomy 20. The karyotype of thenewborn was 46,XY/47,XY,+20 in foreskin cultures and in a second skin culture; blood lymphocyte culture was 46,XY. Aside from diffuse, hypopigmentary swirls along the lines of Blaschko observed on hisextremities and trunk, referred to as hypomelanosis of Ito, the patient is clinically normal at 8¾ years ofage. In addition, he is one of the oldest reported cases of mosaic trisomy 20 confirmed after birth forwhich the clinical outcome has been monitored. This case demonstrates that these trisomy 20 findings are compatible with normal psychomotor development and phenotype. Copyright © 2001 John Wiley & Sons, Ltd.     

我国大学生旅游者环境意识与行为特征研究

作为潜在的生态旅游者群体,大学生对环境问题的认识、态度及其行为倾向对于旅游地生态环境的可持续发展至关重要。文章以南京林业大学为研究对象,通过问卷调查,以配额抽样法探讨大学生旅游者学科专业、性别因素对环境意识的影响,了解环境心理与行为特征,并与国内生态旅游景区旅游者进行对比,研究发现当代大学生旅游者表现出较好的环境态度和倾向,行为意愿上显示出"绿色"的特征,同时专业课程学习以及实践经历能够增强环境认知和情感,对旅游环境与生态知识的渴求和认知程度对整体环境意识水平有较大影响,然而大学生旅游者的环境意识多来源于理论,存在着知行脱节,环境行为滞后于环境情感、意志。应将旅游环境教育与各学科教学结合起来,开展培养环境责任和环保能力的旅游实践活动,加强大学校园环境及文化建设,积极培育大学生旅游环境意识及管理旅游环境行为。     

突发性大气污染事故的应急监测分析

自从人类历史进入工业时代以来,人类的生产力爆炸式增长,生产节奏日益加快。在经济得到空前发展的同时,自然环境也遭受了前所未有的破坏,突发性的大气污染事故愈发频繁。文章结合笔者多年的工作实践经验,简要分析了如何在突发大气污染事故之后迅速进行科学、规范、合理和有效的应急监测。     

污染源颗粒物监测结果偏离的原因探讨

对比玻璃纤维滤筒在不同温度下的前处理效果,对比滤筒、滤膜在特殊情况下采样的差别,综合现场采样及质量控制的因素,查找、分析低浓度污染源颗粒物监测数据出现较大误差、数据失实、缺乏代表性的原因,提出解决办法,确保监测数据的准确性。     

常规洗井和取样法存在问题及新方法介绍

通过分析国内外研究,阐述了常规洗井和取样(以潜水泵洗井,提桶或贝勒管取样为例)过程的一些弊端,并介绍了一种国内文献中未见的方法—低流速法。该法所采得的样品在代表性方面优势更加明显,获得的数据更加准确。     

极性有机化合物整合采样技术在水环境有机污染物监测中的应用

极性有机化合物整合采样技术(Polar organic chemical integrative samplers,POCIS)适用于极性有机污染物的采集,随着新型极性有机污染物的不断出现,该技术已经引起了科学家的广泛关注.本文概述了几种常用的被动采样装置,重点介绍了POCIS采样器的一般结构、富集原理、环境因素如流速、温度、pH、溶解性有机质、盐度及膜的污染等对采样速率的影响,讨论了针对极性物质检测的质量控制和保证以及性能参考物质,综述了POCIS在水环境有机污染物监测中的应用.最后,本文对POCIS的应用前景进行了展望.