Reproductive biology and strategies of nine meloid beetles from Central Europe (Coleoptera: Meloidae)

The reproductive biology of meloid species from Central Europe is investigated by means of laboratory breeding experiments. They show that the total reproductive potential of meloids, with up to 40,000 eggs, largely exceeds prior data. Furthermore, the number of laid eggs strongly relates to the way by which the triungulins find their host. Clutch size correlates significantly with the size of the beetle, while egg size is independent of this. Both clutch size and egg size decrease with each oviposition. For some species, reproductive data are used to demonstrate how they have adapted to their habitat and to point out existing trade‐offs. Based on the obtained results and on an evaluation of the relevant literature, three types of reproductive strategy can be distinguished within the meloids: (1) very high reproductive rates of open field species with phoretic larvae; (2) average reproductive rates of forest populations of species with phoretic larvae and of species the larvae of which search the nests of their hosts actively; and (3) small to average reproductive rates of those species depositing their clutches in the immediate proximity of their hosts' nests.     

New taxa of Rhagidiidae (Acari: Prostigmata) from North America. Part V. Genus Robustocheles Zacharda,with a key to world species of the genus

Six new species of rhagidiid mites from the Nearctic region, Robustocheles (R.) pascuaria n.sp., R. (R.) similis n.sp., R. (Mexia) longichelae n.subgen, n.sp., R. (Lewia) lacustris n. sp., R. (L.) obscuritata n. sp. and R. (L.) spinaea n. sp., are described. Additional morphological data are given for R. infernalis Zacharda and Elliott which is placed in the new subgenus Mexia. A key to adults of the known four subgenera and 15 species of the genus Robustocheles Zacharda of the world is presented.     

Effective strategy of the overwintering of semiaquatic bugs: overwintering of Velia caprai (Heteroptera: Gerromorpha: Veliidae)

Overwintering of Velia caprai was studied during the winter months 2006–2007 in the area of South Bohemia (Czech Republic) by (1) field phenological observations and samples, (2) study of artificially established experimental cohorts in an unheated glasshouse, and (3) auxiliary experiments in a laboratory. Velia caprai has a unique way of overwintering within the gerromorphan bugs that is rare among insects generally; it can overwinter in both an adult and an egg stage. Most females reach sexual maturity before overwintering, mate with mature males, overwinter actively on the water surface and lay eggs during the winter. The dormant eggs can be induced to hatch by increasing temperatures. Winter oviposition can be interpreted as a sign of a risk‐spreading reproductive strategy. The overwintering of both adults and eggs provides a chance to adapt to changes in the local environmental conditions and could be an important determinant in broad variability of life‐history traits.     

中国高校电子邮件网络实证研究

为了挖掘社会网络中人与人之间的交流方式,利用日志数据分析国内某高校电子邮件网络的特性。提取了两种网络：非交互网络和交互网络。结果发现两种网络均有很强的度和强度相关性,但是同配异配性质并不明显。此外,发现高强度节点之间存在富人俱乐部现象,而大度节点之间不存在此现象。最后利用加权适应度算法划分了加权网络的社团结构,发现社团规模累积分布满足幂律分布。结论为进一步建模仿真提供了实证基础。     

汉语依存句法网络的复杂网络性质

基于大规模语料库,建立了汉语依存句法网络,并从复杂网络的角度对该网络进行了系统的实验考察.实验结果表明汉语依存句法网络具有复杂网络的两个基本性质:小世界效应和无标度特性,并在其他方面也体现了复杂网络的重要性质.汉语的这些句法上的统计特性,与捷克语、德语和罗马尼亚语等极为相似,说明虽然不同语言有着极为不同的句法规则,但它们具有类似的统计特性,这种共性对人类语言本质的研究具有一定的启发意义.     

浅谈数学史在数学教育中的作用

数学史在数学教育中具有特殊的重要作用,激发学生学习数学的兴趣,引导学生对数学的理解,从整体上把握数学知识,培养学生的创新意识和探索精神。     

陶行知教育理论在高职历史教学中的实践

陶行知教育思想的核心部分是生活教育理论,该理论对推动当前的职业教育发展,培养符合社会需要的实用人才,仍具有重要的启示和借鉴价值。     

上承式拱桥阻尼支撑加固抗震性能分析

针对上承式拱桥抗震加固的工程需要,提出了加设阻尼支撑的减震控制方案,在结构中增加集中阻尼来减小地震响应．通过尼木大桥加固工程中采用加设粘弹性阻尼支撑方案的有限元地震响应分析,表明粘弹性阻尼支撑能够显著减小拱平面内的位移响应,是一种有效的减震控制方案．     

数学发展的矛盾运动

用唯物辩证法研究数学发展中的矛盾运动,考察数学体系内部的矛盾如何导致了数学史上重大变革的产生. 以非欧几何、群论和集合论的诞生为例说明数学理论与现实世界的矛盾运动,进而用历史的、逻辑的方法说明数学理论能否充分发展最终取决于生产实践和科学实验的发展程度,实践始终是检验数学理论真理性的唯一标准.     

双连拱地铁隧道衬砌结构地震动力响应特征

以西安地铁五号线某区段双连拱隧道工程为背景,建立有限元动力分析模型,选取El-Centro波、西安人工波、Taft波三种代表性波源,分析了SV波作用下地铁双连拱隧道衬砌结构的加速度、动应力、结构变形等动力响应特征,研究结果表明：中隔墙顶部及底部等存在明显拐角的位置应力变化明显高于其他部位,是双连拱隧道的高风险点,隧道抗震设计中应重点关注;地震结束后隧道结构即使未发生破坏,由于所处应力状态的改变,其安全性可能已经降低;隧道变形整体表现为上部结构相对于隧道底板随地震作用产生水平偏移运动,而其幅值受到地震波的峰值加速度、时程曲线分布形式等方面因素影响。