黑线姬鼠不同年龄组种群繁殖特征的研究

系统研究分析了1999—2004年贵州省余庆县黑线姬鼠不同年龄组种群繁殖特征的变化规律。研究期间共解剖黑线姬鼠1011只(其中,雌鼠483只,雄鼠528只)。黑线姬鼠种群性比存在显著的年龄变化,不同年龄组之间种群繁殖力存在显著差异,随着种群年龄的增长,种群繁殖力不断增加。成年Ⅰ组、成年Ⅱ组、老年组是黑线姬鼠种群的繁殖群体,平均怀孕率为45.97%,胎仔数为5.02只,睾丸下降率为91.98%,繁殖指数为1.0618,除平均胎仔数与总平均胎仔数差异不显著外,平均怀孕率、睾丸下降率、繁殖指数均显著高于总体平均值,分别为总体平均值的1.57倍、1.42倍、1.52倍,它们在种群中所占比例的多少与种群数量消长关系密切,可作为预测黑线姬鼠种群数量的重要依据。     

奎屯市昆虫种类调查鉴定

对奎屯市昆虫资源进行了考察,共采集标本800余件,鉴定标本200件,分属10目、75科、144种,讨论了该地区的优势类群,其中,鞘翅目、鳞翅目、半翅目、膜翅目均是奎屯市的优势目,白星花金龟(Postosia brevitarsis Lewis)、榆长斑蚜(Tinocallis saltans)、春尺蠖(Apocheima cinerarius)、杨梦尼夜蛾(Orthosia incerta Hvfnagel)为优势种。     

弱势群体利益表达机制与和谐社会构建

随着改革的深入,我国的社会阶层不断分化,产生了新的弱势群体,这些弱势群体,是社会稳定的不利因素。应建立利益诉求表达机制,拓宽民意渠道,尽最大可能实现利益大体上的均等,促进和谐社会建设。     

大学生非正式群体的教育与管理研究

名目繁多、形式多样的各种大学生非正式群体在高校已经成为非常普遍的现象,在学生当中起着日益重要的作用。对大学生非正式群体的特征、作用和形成原因进行了分析,并就如何正确对待大学生中的非正式群体提出了解决办法。     

我国企业集团财务管理存在的问题及对策

企业产权不清晰、缺乏现代管理理念和统一的财务管理体系、资金运作不规范,缺乏行之有效的财务管理机制和执行预算不坚决等,是我国企业集团财务管理混乱的主要原因。更新管理理念,建立统一的财务管理体制,规范资金运作,强化资金管理是关键。     

Gradient analysis of an eastern sand savanna's woody vegetation,and its long-term responses to restored fire processes

Little information is available comparing historic and modern sand savannas, and how remnants respond to restored fire. We compared short- and long-term effects of restored fire on the Tefft Savanna, a 197 ha eastern sand savanna in northwest Indiana that had undergone three decades of fire protection. U.S. Public Land Survey data from Tefft in 1833 indicate black and white oak barrens, and pin oak savanna, with trees averaging 50 stems/ha and 4 m²/ha basal area. We used ordination and a digital elevation model to assess topographic distribution of tree species in 1986. In 1986, we also compared initial effects of high- and low-intensity dormant season fire on woody vegetation among nine blocks containing black oak, white oak, and pin oak stands. Twenty years later, we compared the same blocks, all of which had been burned three times per decade with low-intensity fires. In 1986, black oak, white oak and pin oak occurred across a gradient of decreasing elevation and slope. At that time, unburned black oak and white oak stands averaged >400 stems/ha and about 10 m²/ha basal area, and their smaller size classes contained non-oak woody vegetation that apparently had invaded with fire exclusion. After initial burns, black oak and white oak stands receiving high-intensity fire averaged <200 stems/ha and had significantly lower oak canopy cover and basal area than unburned stands. Stands receiving low-intensity fire had intermediate oak canopy cover, with basal area similar to unburned stands. Pin oak stands were more fire-resistant, apparently because spring flooding often reduced fire effects. Density, cover and basal area of non-oak tree species were much lower than oaks, and were not reduced by initial burning. Repeated low-intensity burning over 20 years tended to maintain structure caused by initial fires. However, it reduced lower size class stem densities, promoted post-fire sprouting into the shrub layer, and allowed oak basal area to increase in larger size classes. Time since fire regulated shrub layer structure on a 4-year cycle. Density and cover of trees and shrubs returned to pre-burn conditions by the second and fourth growing seasons after fire, respectively, with non-oak tree species exceeding pre-burn cover and density by the fourth season. These results suggest that high-intensity fire is more important than repeated low-intensity burning in structuring and restoring eastern sand savanna, and that non-oak tree species, once established, may be resistant to low-intensity fire.     

虚拟社区中的网络政治参与的“群体极化”

随着网络技术的飞速发展，虚拟社区已经成为一种人类的“另类空间”，为人类提供一个崭新的交流平台和交往环境。而由于网络的固有的特性，使得网民参与政治以群体主体的形式出现，并且在网络政治参与中表现出“群体极化”现象。群体极化对我国的政治文明建设具有双重影响，全面评价群体极化的影响，探索造成群体极化的深层原因，是引导网络政治群体理性参与政治的基础。引导网络政治群体参与政治，防范群体极化，必须采取综合的措施。     

大学生非正式小群体探析

分析了当前大学生非正式小群体大量存在的因素，提出学生工作应加强学生基层组织建设，规范非正式小群体。     

大小叶种儿茶素在植物油中抗氧化性数据的广义估计方程法的检验和分析

在获得有关大小叶种儿茶素在植物油中的过氧化值数据后，怎样通过摆在人们面前的一大堆数据获得正确的结论，从而揭示一定的规律，并能展示其显著性和统计意义，SAS是目前流行的统计分析软件，应用广义估计方程（GEN-MOD）方法，可以从输出的信息中寻找统计上的参数值，来检验和证实结论可靠程度。     

Prospects for hybrid breeding in winter triticale: II. Relationship between parental genetic distance and specific combining ability

Significant relative midparent heterosis (MPH%) for grain yield in triticale (×Triticosecale Wittm.) has generated interest in the development of hybrid cultivars. The objectives of this study were to (i) examine the association between parental genetic distance (GD) and specific combining ability (SCA), (ii) investigate the existence of genetically distant heterotic groups in elite germplasm, and (iii) draw conclusions for future hybrid breeding in winter triticale. Genetic distance between 61 lines was estimated, based on 93 polymorphic simple sequence repeat (SSR) marker loci and 10 AFLP (amplified fragment length polymorphism) primer‐enzyme combinations (PEC). Agronomic data of 206 F₁ crosses and their 61 parental lines grown in six German environments were published recently in a companion study. Correlations were made between SCA for grain yield, number of spikes/m², 1000‐kernel weight and number of kernels per spike with GD estimates of the 56 female and five male parents (testers). Principal co‐ordinate analyses (PCoA) based on SSR data revealed no distinct subgroups in the germplasm. Correlations between GD and SCA were low for all traits (|r| ≤ 0.31), which hampers the prediction of SCA from molecular data. A multi‐stage procedure is recommended for future hybrid breeding in triticale by applying a pragmatic approach for the grouping of germplasm following the early history of hybrid breeding of maize.