Do caterpillars of Dryas iulia alcionea (Lepidoptera,Nymphalidae) show evidence of adaptive behaviour to avoid predation by ants?

Plants bearing extrafloral nectaries can attract wasps, bugs, and mainly ants. Ants can defend plants against herbivores by treating the plant as an extension of their own territory. We evaluated the efficiency of resting sites built by Dryas iulia alcionea larvae as protection against ant predation on their host plant Passiflora suberosa. The results showed that ants on P. suberosa have significant influence on the survival of D. iulia caterpillars. The use and construction of resting sites was recorded through the fourth larval stadium. A strong inverse relationship between the number of resting sites constructed per larva and the developmental stage of the larvae was observed. Additional results suggest that the efficacy of resting sites against cursorial predators decreases with larval development. The behaviour of constructing resting sites probably evolved by natural selection. It is likely that this behaviour was important for the ancestral lineage that gave origin to Heliconiinae genera Dryas, Dryadula and Phylaethria.     

青少年的应对方式、应对效能与心理适应的关系

引入应对效能的概念,探讨青少年的应对方式、应对效能与心理适应之间的关系.结果发现:高水平的应对效能有助于他们更多地使用问题解决和分散的应对方式,而较少使用忍耐的应对方式;应对方式和应对效能都是调节学生感受到的压力与心理适应之间关系的中介变量,应对效能有利于减轻压力导致的焦虑和抑郁情绪.     

20世纪六七十年代的中国钢琴教育

上世纪六七十年代，中国钢琴教育进入了一个特殊的时期，教学条件的艰苦、政治环境的恶化使教学空间极其狭窄。尽管如此，钢琴艺术工作者仍然在特定的历史条件下，在有限的教学空间里，竭力维系着中国的钢琴教育，在钢琴改编曲方面创作了许多优秀作品，达到了新的艺术高度。     

林语堂的《狄氏》改编:追寻逝去的情与志

<狄氏>为宋人廉布小说集<清尊录>中一篇,前此柳宗元<河间传>有相像情节,继后明人小说集对该篇也多有收录或改写.林语堂<中国传奇>将此篇重写,使其变为一始于私通而成于婚姻的爱情故事,小说特别强调婚姻中感情的至上地位.改编后的内容与政治相关涉,寄寓着林氏的人生理想.     

数字地面模型在公路CAD中的应用

论述了数字地面模型（ＤＴＭ）在公路路线ＣＡＤ的实用技术，介绍了在Ａｕｔｏ－ＣＡＤ图形环境下，交互式形成三角网ＤＴＭ的原理与方法，以及如何通过ＤＴＭ生成三维地面和纵、横地面线，进而提高公路路线ＣＡＤ应用的质量与效率     

基于非线性变换的图表示优化

优化是模式识别系统中必不可少的组成部分,优化的效果在一定程度上决定最终的识别结果.本文针对图表示的模式识别系统,提出了基于非线性函数的优化方法,使图表示模式识别更符合可视化与交互式原则.     

当代大学生的心理素质及其优化

大学生的心理素质，决定着高等教育的质量，关系到中华民族的全面振兴。而大学生的心理素质的现状令人倍感忧虑。优化大学生的心理素质刻不容缓。新世纪要求大学生所具有的心理素质是一个多维的复合结构。优化大学生的心理素质需通过多种有效途径。     

嵌套二叉树实现大规模地形实时绘制

实时调入视点可见数据,快速动态地建立连续细节层次(LOD)模型是提高大规模地形绘制速度的关键技术。在数据分块组织的基础上构建了两层嵌套二叉树。通过索引数据二叉树和可见性判断,实现可见数据的实时调入;对可见数据块,通过LOD建模三角形二叉树和设计的基于包围球的节点误差评价函数,实现连续LOD模型的快速动态构建,提高大规模地形的绘制速度。实验表明文中的方法可以取得较高的帧速率和较好的绘制效果,实现了大规模地形的实时绘制。     

Effect of pancreatic secretions upon ileal disaccharidase activities of neonatal miniature pigs

Summary Mechanisms by which pancreatic secretions influence disaccharidase activities in the distal small intestine have been investigated in 1-week-old miniature pigs. Using a combination of biochemical, cytochemical and morphological techniques it has been found that the decrease in lactase specific activity is due solely to a reduction in villus surface area. By contrast, the increased sucrase-isomaltase activities, which occur despite the reduction in villus surface area, are due entirely to increased enzyme expression during enterocyte differentiation.