Variability of the Flower Structure in European Starflower (Trientalis europaeaL.) in Natural Populations

Flower variability was studied in natural populations of European starflower (Trientalis europaeaL.). The results showed that the flower structure in this species is determined by two parameters: the multiplicity of primordia of flower components and the uniformity of flower meristem development. The frequencies of nonuniformly developing flowers differs depending on the habitat. It appears that both parameters are largely determined by random fluctuations.     

Spatial Distribution of Sables in the Middle Ob Region

Results of stationary studies on the spatial location of sables (Martes zibellinaL.) belonging to different age and sex groups are summarized. Mapping the sites where 388 animals were taken, it was found that young animals tended to live near floodplains; adult animals, on watersheds. Analysis of sables taken by commercial hunters (n= 1833) made it possible to estimate the age composition and the degree and spatial distribution of the hunting pressure on sable populations in three areas of the Ob region. The spatial separation of young and reproductive animals is interpreted as a group adaptive response to the specific distribution pattern of different habitats typical of this species and to the pattern of animal elimination. It is proposed to use the specific pattern of animal distribution for maintaining the size of the population that is subject to hunting. Specifically, reserve (reproductive) territories should be organized in watershed areas.     

区域土地利用结构的信息熵分异规律研究

根据对全国及东中西部、浙江省及各地市、杭州市所属的5个县市的土地利用结构信息熵的计算分析,结果表明,土地利用结构的信息熵值可以用来反映一区域土地利用系统的有序程度。一般说来,信息熵值愈大,土地利用系统的有序程度愈低,反之亦然;土地利用结构的信息熵值具有空间分异规律,在全国、浙江省和杭州市3个层面上均表现出信息熵值自沿海向内陆递减;土地利用结构的信息熵值在时间上具有动态演变规律。土地利用结构信息熵可综合反映某区域在一定时段内各种土地利用类型的动态变化及其转换程度,对于区域土地利用结构调整具有指导意义。     

长江下游沿线土地利用区域结构演化分析

论文利用1985和2000年LandsatTM数据和相关统计资料,对长江下游近15年来土地利用区域结构演化进行了研究。研究揭示了长江下游沿线区域土地利用结构的变化趋势、土地利用结构时空演化类型及土地利用格局与社会经济因子间的关系。研究表明:近15年来长江下游沿线区域土地利用变化总体表现为耕地数量减少和建设用地增加的趋势;区域内土地利用变化时空演化类型可以划分为五大类;区域土地利用格局与社会经济因子之间可以用3个典型相关变量表示,耕地、建设用地、林地与草地变化分别对应于不同的社会经济解释因子。     

The role of migration and founder effect for the evolution of cooperation in a multilevel selection context

The idea that natural selection can be meaningfully applied at the group level may be more important than previously thought. This perspective, a modern version of group selection, is called multilevel selection. Multilevel selection theory could incorporate previous explanations for the evolution of cooperation including kin selection. There is general agreement that natural selection favors noncooperators over cooperators in the case of an unstructured population. Therefore, the evolution of cooperation by multilevel selection often requires positive assortment between cooperators and noncooperators. The question is how this positive assortment can arise in the ecological meaning. We constructed an individual-based model of multilevel selection and introduced migration and evolution. The results showed that positive assortment was generated especially when a migration strategy was adopted in which individuals respond specifically to bad environmental conditions. It was also shown that the founder effect in the evolutionary process could further facilitate positive assortment by working with migration. We analyzed assortment by using relatedness defined in group-structured populations. The fact that cooperation was achieved by such migration and by the founder effect highlights the importance of sensitiveness to the ecological environment and of fluctuations in group size, respectively.     

干旱区生态安全问题及其评价原理——以新疆为例

普遍的生态敏感性和整体的生态退化趋势,使干旱区成为社会适应和经济适度极端脆弱区,其生态安全问题的典型性和突出性,为完善区域生态安全评价理论体系提供了理想靶区。根据生态安全评价的一般原理和目标,通过剖析新疆绿洲区生态安全问题的驱动、压力和响应机理,主要利用地带性共扼和非地带性耦合分析方法,从哲学观和生态系统、景观生态、土地类型及其稳定性格局层面,初步构建了干旱区生态安全评价的基本原理,得出确保有效的生态需水和生态水位,协调水生态及水安全功能,是干旱区生态安全评价的基础;基于生态承载和再生恢复禀赋的合理、适度利用优势资源,是绿洲开发的生态安全保障;维护天然绿洲和荒漠的“生态标本”价值,引导土地利用的生态化转向,是绿洲生态安全评价的客观依据;通过系统的生态规划和景观设计,保持异质景观的竞争性统一和生态圈层结构的动态稳定性,是干旱区生态安全评价的核心内容。     

旅游景区(点)系统空间结构随机聚集分形研究——以南京市旅游景区(点)系统为例

根据旅游景区(点)系统自组织演化的特征,以南京市旅游景区(点)系统为例,采用随机聚集分形的方法对其空间结构进行了研究。认为景区(点)系统的演化类似于有限扩散集团凝聚模型,得出景区(点)系统空间结构是分形的,具有比较明显的随机聚集分形结构,在不同的地理区域上表现为不同的系统演化时段,空间结构上的向心性作用也有强弱之分,从系统的聚集中心向四周是景点密度衰减的。指出随机聚集维数的测算与分析是景区(点)系统空间结构自组织优化趋势的判据,同时提供了优化的途径。     

建筑物结构变化对大气污染影响的试验研究

通过风洞实验对大气污染物扩散特性进行了模拟试验研究,重点讨论了建筑物结构形式变化对周围环境污染浓度的影响,在此基础上对影响污染浓度的各个要素进行了分析与讨论,得到了大气污染物在复杂结构建筑物之间扩散的一般规律。     

楔形障碍物与火焰的作用

采用多镜头Cranz ＆ Schardin高速摄影机,对卧式燃烧方管内楔形障碍物与CH4/空气预混火焰的相互作用进行了实验研究,获得了高清淅度的障碍物诱导火焰失稳的分幅时序照片.基于RANS方法,对上述复杂物理现象进行了数值模拟.计算结果与实验结果基本相符,反映了火焰在管内传播与变形的详细过程,得到了楔形障碍物所导致的火焰加速与变形的内在机理,揭示了火焰传播过程中由层流燃烧向湍流燃烧转捩的本质.     

黄河三角洲二元结构与多元可持续发展初探

黄河三角洲由石油资源的开发而兴起,其区位条件和油气资源条件都十分优越,但目前仍处于经济发达地区的低谷区。通过对二元结构系数的定量分析,发现该地区具有明显的复合二元结构特征,即“油地+城乡”,二元结构是制约三角洲持续发展的一个重要限制性因素。目前,石油产业的全面改组改制、优越的外部环境和自身基础条件、东营港扩建及其附属加工制造业基地的立项、综合性交通运输网络体系的形成等都是三角洲全面发展的难得机遇。要实现多元可持续发展的目标,必须转变观念,由“以油建城”到“以港兴城”、大力发展资源深加工工业和具有竞争优势的制造业;构建高效生态农业经济体系;推进城市的“内聚式”发展。