植物种群资源竞争与共存的理论模型研究

自然生态系统不同植物种群之间存在着广泛的竞争,且多种植物种群可以共存,即具有生物多样性。经典的资源竞争模型(莫诺模型)支持生态学上的"竞争排斥原理",不适用于阐释自然生态系统不同植物种群间的竞争与共存。根据植物生态系统的特点,引入植物种群的生长率随着物种个体大小/个体数增加而逐渐趋于饱和的性质,建立自抑制资源竞争模型。该模型与莫诺模型的本质区别在于,物种的临界可利用资源随种群密度增加而上升,从而可以达到不同物种间的平衡。数学分析及数值模拟结果表明,该模型可允许多物种稳定共存(即共存的物种种类数可以多于供给其生长的资源种类数),同时优势物种随资源供给率增加而依次变化。     

当前遥感技术发展及产业化分析

目前,我国遥感技术的研究发展和产业化面临着巨大的需求和发展机遇,完善遥感技术体系的建设,实践科技发展三大战略,规范和提高遥感产品生产能力,将遥感技术发展成为一项工业,是遥感技术顺应新时代的战略选择。本文基于产业经济学原理和遥感技术本身特点,对遥感产业化提出了技术发展、产业化和市场竞争政策的建议。     

What about managerial geography?

A business school perspective to Corporate Geography is offered. The mission is to provide an executive with operational tools for the creation of wealth. A search for the tools is better initiated with manufacturers and retailers. Individuality among corporations and markets makes deductive theories hazardous, a fact shown by examples from IKEA, Scania and Volvo Truck. Case studies, classified by a competitive situation, are seen as a more practicable alternative. From a large number of cases typical patterns can be derived. Anomalies indicate substandard or outstanding behavior. Their explanation contributes to the executive tool set. A unified approach of the currently scattered pieces is propagated.     

Interspecific Competition between Tetrachthamalus oblitteratus and Tetraclita squamosa

Abstract. Direct evidence for interspecific competition between Tetrachthamalus oblitteratus and Tetraclita squamosa is provided. Tetrachthamalus oblitteratus is smothered and eliminated from the main midlittoral zone by encrusting Tetraclita. The disjunct distribution of Tetrachthamalus can be explained by elimination through competitive exclusion.     

The Epibiotic and Endolithic Species Associated with the Gastropod Shells inhabited by the Hermit Crabs Paguristes Oculatus and Pagurus Cuanensis

Abstract. Over 120 species, including epizoites, endolithic organisms, and an epiflora are associated with the gastropod shells inhabited by the hermit crabs Paguristes oculatus and Pagurus cuanensis in the North Adriatic Sea (Gulf of Trieste). The symbiotic organisms include members of three trophic levels - primary producers (rhodophytes), primary consumers (active and passive filter feeders), and secondary consumers (carnivorous species). Many of the invertebrates show a preferred distribution on the shells. The shells are a mobile substratum for a specific community. They are a sediment- and predator-free surface, and for their size are extremely stable substrates in terms of both time and orientation.
The hermit crab microbiocoenosis is a dynamic phenomenon that can be studied as a functional unit. The symbionts are responsible for two simultaneous processes - a constructive and a destructive process on the shells. Shell deterioration is due primarily to biological processes, not to mechanical destruction. The more frequently occurring species were classified according to their role in reinforcing or weakening shell structure. These developments are related to hermit crab activity. Epizoites grow through several shell changes by hermit crabs, and a number of forms are capable of surviving the final deposition of the shells.     

UV-B辐射对3种海洋微藻的种间竞争性平衡的影响

为探讨UV-B辐射对海洋生态系统的影响，研究了短期(2d)UV-B辐射对金藻8701、小新月菱形藻和亚心形扁藻3种藻单养的敏感性比较以及长期(21d)UV-B辐射对3种藻混养的种间竞争性平衡的影响。实验表明，(1)UV-B条件下。单养和混养情况下，最敏感的藻是金藻8701，小新月菱形藻次之，亚心形扁藻最不敏感；(2)增强的UV-B为对UV-B具有高耐受力的亚心形扁藻提供了竞争优势，使种间竞争平衡向着有利于亚心形扁藻的方向发展，到第21天，UV-B辐射(2．88J／m^2，5．76J／m^2)的处理组中，亚心形扁藻成为优势种。     

The market(able) place of school geography scholarship, 2007–2016

This report analyses a decade of geography scholarship student entry and achievement data (n = 10,205) to reveal patterns and trends of high‐achieving school students. The study is an exploratory analysis, the aim of which is to describe where the greatest scholarship success has occurred, as well as attendant demographic characteristics of New Zealand's most capable geography students and their schools. Emerging from the regions is a localised story of students from an extremely narrow number of schools achieving disproportionate scholarship success. This raises questions in the wider geography teaching community about the possibility of a broader constituency achieving scholarship awards.     

Growth coalitions in declining cities: casinos,redevelopment, and inter-urban competition

Casino development is a popular strategy for urban redevelopment in declining cities. I examine the process of casino acquisition in the former Canadian automotive capital, Windsor, Ontario – one of the first cities in North America, outside of Atlantic City and Las Vegas, to host a resort casino. Drawing on 20 interviews with urban elites and the local news media, I explore the interplay between a local growth coalition and State interests in the development of Casino Windsor. To capture maximum revenue for provincial coffers, provincial interests used competition between economically depressed cities to co-opt the Windsor casino alliance’s project . Windsor’s urban elites, however, continue to “talk” urban entrepreneurialism, perpetuating the myth that municipal entrepreneurialism was an effective strategy for this struggling city. These findings suggest that the importance placed on the entrepreneurial capacity of local growth coalitions in urban redevelopment studies may be misplaced, especially in peripheral and declining cities.