基于WEBGIS的校园地理信息系统的模型设计

随着地理信息系统（GIS）技术的飞速发展,“数字校园”的建设有了显著的成果。笔者在分析现有校园信息管理系统的基础上,研究了将WEBGIS技术与校园其他MIS系统集成的方法。结合“数字校园”建设的具体实例,对校园地理信息系统的实现提出了具体的设计方案。并根据基础地理资料,实现了基于B／S结构的校园地理信息系统,为实现校园数字化管理提供了有效的解决办法。     

城市森林在城市生态建设中的作用

通过对城市森林及生态城市的阐述,重点阐述了城市森林的作用及它在城市生态建设中不可取代的地位。     

Species compositional similarity and ecoregions: Do ecoregion boundaries represent zones of high species turnover?

The concept of an ecoregion, a discrete spatial area where species composition is presumed to be relatively homogeneous compared to that between areas, has become an increasingly common conservation tool. We test the effectiveness of one ecoregion delineation (World Wildlife Fund) in capturing patterns of change in species composition of birds, mammals, and trees across the United States (excluding Hawaii) and Canada, and describe the extent to which each ecoregion boundary is concurrent with relatively large changes in species composition. Digitized range maps were used to record presence/absence in 50 × 50 km equal-area grid cells covering the study area. Jaccard’s index of similarity was calculated for all pairs of cells in the same or adjacent ecoregions. The average rate at which similarity declined with geographic distance was calculated using pairs of cells within the same ecoregion (intra-ecoregion turnover) or using pairs of cells in adjacent ecoregions (inter-ecoregion turnover). The intra-ecoregion rate varies widely among ecoregions and between taxa, with trees having a faster rate of similarity decline than mammals or birds. For all three species groups, most ecoregion boundaries have similar rates across them (inter-ecoregion) than that within each adjacent ecoregion (intra-ecoregion), with the exception of zones of transition between biomes and major geographical features. Although the ecoregion concept is useful for many other conservation applications, the lack of systematic, high turnover rates along ecoregion boundaries suggests that ecoregions should not be used as a quantitative basis for delineating geographic areas of a particular taxonomic group.     

构建高校图书馆与农家书屋的协作机制推动区域经济持续发展

从活跃农民群众文化生活、发展和繁荣农村文化的角度出发,从促进社会主义农村经济的协调发展、全面提高农民综合素质入手,对当前“农家书屋”发展现状以及存在的问题进行分析,探讨了高校图书馆对“农家书屋”工程建设的优势和促进“农家书屋”工程建设的有效方法和途径。     

木薯种质资源离体保存技术研究

为探讨木薯(Manihot esculenta Crantz)种质资源的离体保存方法,以GR891木薯品种试管苗为试材,研究了植物生长抑制剂(PP333、B9、S3307、ABA)对试管苗在常温(25℃)条件下的保存效果。结果表明,在培养室温度(25±2)℃、光照度1500~2 000 lx、光照时间12 h/d的条件下,培养基中加入PP333、B9和S3307均可提高木薯试管苗的存活率。在MS+6-BA 0.2 mg/L+NAA 0.1 mg/L+蔗糖30 g/L+琼脂6.5 g/L培养基上,木薯常温保存的适宜PP333质量浓度为1.0~1.5 mg/L或B9和S3307质量浓度均为0.5~1.0 mg/L,保存240 d时存活率超过90%,试管苗根系发达、叶色浓绿、生长健壮,0.2~2.0 mg/L ABA培养基上试管苗长势和存活率都明显低于CK(对照)。     

河北省夏播玉米品种主要农艺性状演变规律的研究

通过对河北省1975—2002年审(认)定夏播玉米杂交种主要农艺性状的分析,认为河北省夏播玉米杂交种主要农艺性状的演变规律是:株高和穗位有增高的趋势;果穗由细长形向短粗形(筒形)演变,穗粒数增多,千粒重则趋于稳定;株型由平展型逐渐向紧凑、半紧凑型演变;半硬粒型和硬粒型品种增多,马齿型品种的比例降低;产量水平稳步提高,递增幅度逐渐减少。品种的生育期有延长的趋势,适宜种植密度则在经历了由低到高的变化过程以后,近年又呈现逐渐回落的趋势。     

Generations in captivity increases behavioral variance: considerations for captive breeding and reintroduction programs

Long-term maintenance of captive populations followed by release of captive animals into the wild is one of many approaches to endangered species conservation. To assess captivity's effects on behavior, a simulated predator was presented and response behaviors measured in oldfield mice, Peromyscus polionotus subgriseus. The animals tested were from four populations collected from Ocala National Forest, Florida, and held in captivity for varying numbers of generations: 35, 14, 2, and 0 (wild caught). Results show (1) that the more generations a population has been in captivity, the less likely an individual is to take cover after seeing a predator and (2) variance in predator-response behaviors increases with generations in captivity. These results point to two ways in which captivity can compromise animal behavior and, in turn, the success of reintroduction programs. First, because individuals from populations that have been in captivity for multiple generations seek refuge less often than their wild counterparts, they might experience increased mortality in the wild due to predation. Second, increased behavioral variance could translate into decreased survivorship upon reintroduction. Therefore, more individuals will need to be released to reach the targeted wild population size.     

1940年代的天水水土保持试验区述论

1942年天水水土保持试验区成立,中国第一支水土保持研究的科研队伍积极开展水土保持实验,宣传水土保持思想,推广水土保持技术与保土作物,不仅推动了中国现代水土保持科学的发展,并将之推进到系统化、组织化研究的阶段,奠定了水土保持学诞生的基础;还为中国锻造了第一支水土保持研究队伍,为水土保持研究的制度化提供了样板。同时,它还为西北地区水土保持与区域经济的可持续发展提供了极为难得的科学数据与理论支撑。     

柑橘黄龙病疫情运动规律与预警模型研究

为了揭示柑橘黄龙病整体疫情入侵、扩散、流行等运动规律,对柑橘木虱种群的数量消长情况进行多年多点的系统监测,同时在柑橘黄龙病果实显症期采用全境式普查方法开展疫情调查。2002-2010年连续8年的监测和普查结果表明,柑橘黄龙病疫情入侵分布呈南重北轻、东高西低的特征,其扩散趋势为自南而北逐年推进,并呈螺旋式上升。疫情长期运动一般需经历入侵上升、高位运行、受控回落周期性变化,其运动周期为10年左右,并建立时序运动模型: P=-00044N2+0056N －00698(n=9,r=09552**,r001=07977)。应用上述模型进行逐年修补,若预测下年度果园加权发病率在1%以上,则可发布预警。     

土壤铅污染对密毛白莲蒿茎叶解剖结构影响的研究

对200 mg/L铅溶液处理的非矿区、矿区密毛白莲蒿的茎、叶解剖结构进行了比较研究.结果表明,非矿区密毛白莲蒿茎在铅胁迫下组织结构变化较小.矿区密毛白莲蒿茎表现出对铅的适应性,茎表皮加厚,细胞壁加厚,木质部导管壁出现加厚现象,导管中有黑色物质.非矿区密毛白莲蒿叶在铅胁迫下整个组织结构极其松散,组织内部的细胞形状不规则,细胞大小不规律,且排列混乱,部分细胞出现了解体的现象,完整的细胞中叶绿体含量明显减少.而矿区密毛白莲蒿叶解剖结构变化较小,其组织结构较完整而且内部细胞排列很紧密,细胞形状较规则,大小均一.矿区密毛白莲蒿在铅胁迫下表现出了很强的耐受性,为铅污染土壤植物修复的理论研究和技术实施提供了一种新的种质资源.