UNDERSTANDING A WATERSHED FROM THE BIOLOGICAL VIEWPOINT1

In watershed management the effects of plants on water cannot be considered a constant and forgotten because: plants of different sizes and forms use water at different rates and plants of the same size differ in their needs for water because of anatomical differences. Many common denominators are present in all watersheds covered by vegetation. Forces exerted on the soil water by vegetation, climate and soil are the same kinds of forces. The differences between watersheds in water yield potential appear to be due to differences in the degree in which these forces are exerted. However, the influence of biotic factors are more individual. The similarities and differences existing between watersheds suggest some principles that can be used as guides to understanding individual watershed problems and as possible guides to determining when, how, and where to treat a given watershed. Eleven principles are given and their application to the definition and solution of biological or vegetational problems of watershed management are discussed.     

三大密码体制的理论研究及应用中的问题

随着网络信息技术的飞速发展，网络上传输数据的安全性越来越差，而数据加密是保证信息安全的一种有效手段。本文概括介绍了国内外三大密码体制(对称密码、公钥密码和量子密码)的理论与技术及其目前重点研究的方向。     

比色法快速测定室内空气甲醛含量

室内空气甲醛的现场快速监测技术已成为环境监测的热点研究领域,旨在为普通家庭提供室内空气甲醛现场监测方法。优化了甲醛吸收液用量、自然吸收时间及吸收液与空气接触面积对监测方法的影响,制作了用于目测室内空气中甲醛含量的标准比色卡,方法简便、快速、经济、实用,可望在普通家庭中得到广泛应用。     

EMS产品振动试验操作常见问题的发现和解决

对EMS(汽车发动机管理系统)产品在振动试验操作中的常见问题、以及如何发现和解决这些问题作了介绍并从中得到结论,EMS产品振动试验操作中的常见问题是可以通过有效的方法及时发现或解决的。     

Conservation Success as a Function of Good Alignment of Social and Ecological Structures and Processes

How to create and adjust governing institutions so that they align (fit) with complex ecosystem processes and structures across scales is an issue of increasing concern in conservation. It is argued that lack of such social‐ecological fit makes governance and conservation difficult, yet progress in explicitly defining and rigorously testing what constitutes a good fit has been limited. We used a novel modeling approach and data from case studies of fishery and forest conservation to empirically test presumed relationships between conservation outcomes and certain patterns of alignment of social‐ecological interdependences. Our approach made it possible to analyze conservation outcome on a systems level while also providing information on how individual actors are positioned in the complex web of social‐ecological interdependencies. We found that when actors who shared resources were also socially linked, conservation at the level of the whole social‐ecological system was positively affected. When the scales at which individual actors used resources and the scale at which ecological resources were interconnected to other ecological resources were aligned through tightened feedback loops, conservation outcome was better than when they were not aligned. The analysis of individual actors’ positions in the web of social‐ecological interdependencies was helpful in understanding why a system has a certain level of social‐ecological fit. Results of analysis of positions showed that different actors contributed in very different ways to achieve a certain fit and revealed some underlying difference between the actors, for example in terms of actors’ varying rights to access and use different ecological resources. El Éxito de la Conservación como Función de una Buena Alineación de Estructuras y Procesos Sociales y Ecológicos     

高要求模式SIS异型冗余结构PFH计算模型*

为了满足石油化工生产中对高要求操作模式下采用异型设备的安全联锁回路进行SIL定级的需求,避免因误用同型PFH公式导致SIL等级评估误差。考虑各通道差异性及其失效顺序的遍历性,以MonteCarlo仿真值为多元线性回归模型观察样本,以改进共因失效部分多样性修正因子确定方法,提出异型KooN冗余结构每小时危险失效平均频率(PFH)的计算公式;比较该模型独立失效部分与异型1oo2结构Markov模型PFH结果,并分别将该模型和传统同型PFH公式应用于海上采油平台高完整性压力保护系统(HIPPS)异型关断阀子系统的比较分析。研究结果表明:在不同检测周期内,所提出的PFH计算模型与Markov模型PFH计算结果相对误差均保持在10-3数量级;但当检测周期大于3 a时,使用同型PFH公式会出现对HIPPS子系统SIL等级的误判,造成井口压力联锁保护功能过保护或欠保护。研究结果有助于生产单位准确评估联锁保护风险和设备维护投入。     

A composite measure of habitat loss for entire assemblages of species

Habitat destruction is among the greatest threats facing biodiversity, and it affects common and threatened species alike. However, metrics for communicating its impacts typically overlook the nonthreatened component of assemblages. This risks the loss of habitat going unreported for species that comprise the majority of assemblages. We adapted a widely used measure for summarizing researcher output (the h index) to provide a metric that describes natural habitat loss for entire assemblages, inclusive of threatened and nonthreatened species. For each of 447 Australian native terrestrial bird species, we combined information on their association with broad vegetation groups with distributional range maps to identify the difference between the estimated pre-European and current extents of potential habitat, defined as vegetation groups most closely associated with each species. From this, we calculated the loss index (LI), which revealed that 30% of native birds have each lost at least 30% of their potential natural habitat (LI = 30). At the subcontinental scale, LIs ranged from 15 in arid Australia to 61 in the highly transformed southeastern part of the country. Different subcomponents of the assemblage had different LI values. For example, Australia's parrots (n = 52 species) had an LI of 38, whereas raptors (n = 32 species) had an LI of 25. The LI is simple to calculate and can be determined using readily available spatial information on species distributions, native vegetation associations, and human impacts on natural land cover. This metric, including the curves used to deduce it, could complement other biodiversity indices if it is used for regional and global biodiversity assessments that compare the status of natural habitat extent for assemblages within and among nations, monitor changes through time, and forecast future changes to guide strategic land-use planning. The LI is an intuitive tool that can be used to summarize and communicate how human actions affect whole assemblages, not just threatened species.     

Population Biology of Cichorium intybus L. (Asteraceae) of the Middle Don River Basin

The stages of ontogeny and morphogenesis of the common chicory were characterized on the basis of long-term observations. A comparative analysis of seed productivity was performed, and the pool of viable seeds in the soil was determined. The ecological–cenotic relationships and the types of population strategy of the species were estimated.     

南渡江水质评价浅析

采用共源点灰色聚类法对南渡江海口水域 1 993年枯水期水质进行评价 ,结论为I类水质。与共斜率灰色聚类法进行比较 ,该法更简化 ,加权含义更确切。     

海岸带资源开发利用的环境影响经济评价研究

通过对海岸带资源开发利用的外部性特征的分析,提出对开发项目进行环境影响经济评价.同时对海岸带资源开发利用环境影响经济评价的具体步骤:建立影响因子名录、建立影响名录、影响的筛选分析、影响的量化、影响的货币化(文献筛选、价值调整、计算经过贴现的总值)及估算因素分析等依次进行了阐述,理论上环境影响的经济评价是促进海岸带资源有效配置的一个重要手段.在很大程度上可以抑制单一开发项目的外部不经济性给海岸带公共物品资源和公众社会福利造成的不利影响;可以弥补现行的单一项目环境影响评价和常规经济分析中较少考虑环境影响量化的不足.