Land-Cover Assessment of Conservation and Buffer Zones in the BOSAWAS Natural Resource Reserve of Nicaragua

The BOSAWAS Natural Resource Reserve of Nicaragua was established in 1991, to protect a portion of the remaining tropical rain forest and to promote the sustainable use of the region's resources. Information required to effectively manage the reserve includes the extents and locations of present land-cover types and recent land-cover changes in the management use zones that were delineated by local indigenous communities. These zones include areas designated for conservation, limited resource extraction, agriculture, and watershed protection. Land-cover for 1986 and 1995 was identified for three of the communities from remotely sensed images and then input into a geographic information system database to identify land-cover types within these management use zones. For both dates of the analysis, advanced forest was the dominant land cover, with the conservation zones entirely forested. The amount of both agricultural land and scrub/early secondary forest increased between the two dates, with much of these land-cover classes occurring in the agriculture zones. Conflicts between the land-cover present and designated use were identified in some of the limited-use buffer and watershed protection zones. Changes between 1986 and 1995 were identified by overlaying the two land-cover data sets. Three change processes were identified as occurring: deforestation, reforestation, and reconversion. Changes were concentrated in the agriculture zones but were found to occur in every type of zone, except for conservation. The results of this study will establish baseline information for the future management of the BOSAWAS Reserve, an important component in uniting conservation areas along the Central American isthmus.     

Trout Population Responses to Restoration of Stream Flows

There are numerous demands for the limited water supplies in the Rocky Mountain (USA) region, and controversies surrounding instream flows abound. A specific problem involves water diversions (i.e., small dams that shunt water out of stream channels) during the summer irrigation season. We developed an approach to assess the effects of restoration of natural or less-than-natural summer flows on trout that accounts for variation in habitat over long segments of low-gradient, alluvial-valley streams. The approach has utility for managers because it can be conducted with hydologic data, aerial photographs, topographic maps, and a spreadsheet without extensive fieldwork. We applied the approach by assessing the effects of different summer flows on abundance of brown trout (Salmo trutta) in several streams annually dewatered in the Salt River Valley of western Wyoming. The assessment approach can be calibrated for other trout species and areas of the Rocky Mountain region.     

多源遥感数据沙尘暴强度监测的信息可比方法

综述了利用遥感技术进行沙尘暴监测研究的国内外进展，提出了利用多源遥感数据识别和提取沙尘暴信息的新方法，利用近红外1．6μm波段特性，构建了可比沙尘强度指数。研究表明：利用卫星探测器11μm，12μm波段差值进行沙尘暴信息识别和提取，可以达到满意的效果，但不能刻画沙尘暴强度；构建的可比沙尘强度指数，能够解决多源遥感数据由于卫星平台、监测时间、监测区域等不同因素导致的监测结果不可比的问题；同时监测结果与地面气象站监测数据有较好的一致性，能够从时间、空间两方面刻画沙尘暴强弱分布，可以作为沙尘暴定量研究的参数，为利用多源遥感数据持续定量地监测沙尘暴的起源、移动、传输路径、扩散等待征奠定了基础。     

CBERS-1在国土资源与环境遥感调查中的应用

利用CBBRS－1／CCD中国、巴西地球资源卫星遥感信息源，解决了长期困扰新疆遥感研究的基础信息源问题，并且多专题、多层次、多角度地进行了信息源的处理、信息提取和专题分析，编制了一系列资源环境专题图件，提供了一整套包括土地利用、水资源、森林资源、草地资源、地质矿产资源、以及土地荒漠化等在内的遥感调查数据，为新疆在新的形势下，进行土地规划、生态环境建设、区域经济发展等工作，提供了重要的科学支撑和技术保障。     

基于χ~2优化方法的铸钢侧架原始裂纹尺寸分布研究

将铸钢侧架清砂后未经修复的原始裂纹尺寸进行了统计 ,综合运用参数的点估计方法和区间估计方法 ,以置信区间作为优化的约束条件 ,提出了对检验值进行最优化处理的方法 ,并运用二参数约束非线性优化方法的直接解法 ,搜索出最佳点估计值。经过对裂纹尺寸分布参数的计算证明 ,其结果符合对数正态分布     

航片遥感在城市防震减灾系统中的应用

当前城市建设发展变化很快 ,航片遥感技术应用于城市防震减灾信息系统已成为必然的需要。采用航片遥感技术 ,城市防震减灾信息系统可直接从航片扫描图获取信息 ,在较短时间内建立起各类特征数据库。本文介绍了对航片的选择与应用 ,航片扫描图的电子矢量化技术及与之相应的资料调查工作 ,并对系统数据库维护进行了探讨。     

基于资源安全的企业人才风险管理

从资源安全的角度出发 ,笔者阐述了企业人才资源的重要性 ;对我国企业目前面临的主要人才风险进行了识别 ;指出我国企业目前的人才风险主要来自人才外流、人才获取、人才道德和人才风险意识四个方面 ;强调了我国企业加强人才风险管理的重要意义。从人才风险引起的各项损失及其损失概率的角度 ,提出了企业进行人才风险估测的方法 ;建立了人才风险损失模型 ;指出了我国企业的人才风险管理、有效防范人才风险的途径。     

正辛醇/水分配系数的测定及估算方法

介绍了正辛醇/水分配系数的测定和估算方法。将现有的测定方法分成直接法和间接测定法进行了介绍和评价。直接法主要介绍了摇瓶法、两相滴定法和萃取法;间接法主要介绍了产生柱法和色谱法。给出了不同测定方法的使用范围及其局限性。在估算方法介绍中,将现有的辛醇/水分配系数的估算方法按其对溶质的处理方法不同分为两大类进行了介绍,一类是以整个分子为研究对象的分子法,如摩尔体积法;另一类是根据分子的结构信息进行估算的结构性能法,如分子连接性指数法,基因贡献法。介绍了现有基团贡献法如Leo碎片常数法、Meylan和Howard的AFC基因贡献法、三水平基团贡献法、基团贡献溶剂化模型法、UNIFAC基团贡献法的优缺点及其使用局限性。提出了估算方法的发展方向。     

基于GIS的地震现场灾害损失评估系统

地震现场灾害损失评估地理信息系统(MapEDLES 2001 for Windows)是通过组件技术实现的GIS应用系统.系统实现了数据库管理、地图创建、浏览查询、地震破坏抽样统计与灾害损失评估具有集地图、统计图、表格、文字于一体的评估报告自动快速生成、空间数据远程交换、现场视频图像管理与播放等功能.介绍了该系统的灾害损失评估原理、设计思路和系统功能等.     

浅谈遥感监测水环境

目前，遥感监测能有效解决水环境监测的大范围性、连续性、动态性以及高效性等技术问题。遥感监测越来越受到环保部门的重视。