第二次世界大战后英国乡村景观研究的脉络走向及启示

英国是全球乡村景观建设和发展的典范。从地理学、生态学及规划学等综合的视角出发,首先从社会背景上分析二战后英国乡村景观的演变轨迹;其次从学术背景梳理英国乡村景观的研究历程,并从学科角度提炼不同阶段的研究重点及研究特征;最后从研究趋势方面讨论学者们最新的研究议题。在梳理和总结英国乡村景观研究的基础上,提出对中国乡村景观研究的启示和借鉴。     

Investigations of the bottom current sculpted margin of Hatton Bank, NE Atlantic

The northwest Hatton Bank margin is an ideal locality to demonstrate the interaction between bottom currents and slope configuration in controlling the distribution and morphology of bottom current deposits. The slope area investigated is isolated from any major terrigenous sediment supply and at present is influenced by the Deep Northern Boundary Current (DNBC). Swath bathymetry and high resolution acoustic data allow us to evaluate both local and regional controls on slope sedimentation and the possible mechanisms for bottom-current velocity variability across a slope setting within the NW European continental margin. The slope exhibits sculpting by bottom currents that flow in a predominantly southwest to northeast direction, and is only locally modified by slope failures. Positive relief features such as the Endymion Spur play an important role in constraining and accelerating bottom-current flow and, consequently, in redistributing sediment along the margin. We demonstrate that the size, morphology and distribution of bottom-current deposits along the slope vary as a function of the interaction between bottom currents, regional slope orientation and local seafloor topography.     

闽南-台湾浅滩渔场蓝圆鲹和鲐鱼群聚空间分布的研究

根据闽南-台湾浅滩渔场灯光围网信息船1990～2002年的渔捞记录，研究该渔场蓝圆鲹和鲐鱼群聚空间分布．结果表明，中上层鱼类蓝圆鲹和鲐鱼年间数量变动具有时间同步的特征，年均网次产量显著相关．蓝圆鲹与鲐鱼群聚区分布差异表现在：蓝圆鲹分布的海区水深较鲐鱼浅，蓝圆鲹和鲐鱼分布渔区的水深，春季分别为40～660m和40～70m，夏季分别为30～50m和30～60m，秋、冬季分别为30～60m和40～60m；鲐鱼的群聚区分布较偏北、偏向台湾岛西岸，蓝圆鲹的群聚区分布较偏南、偏向台湾海峡的中心区域；蓝圆鲹与鲐鱼群聚区的时空隔离、彼此取代比较明显．蓝圆鲹与鲐鱼的群聚区存在一定的重叠，与其种间对食物的竞争有关．两鱼种所出现两种适应性趋向。增加了它们在同一生境中长期共存的可能性．     

闽南-台湾浅滩渔场蓝圆鲹资源的评估

以1971—1987年的蓝圆鲹叉长组成资料,应用体长股分析法评估了闽南-台湾浅滩渔场蓝圆鲹的资源。结果表明,1971—1980年的现存资源数量和生物量分别为45292×10~5尾和9.49×10~4t,1981—1987年分别为63908×10~5尾和13.51×10~4t;1971—1980年和1981—1987年的瞬时捕捞死亡率分别为0.6347和0.4859。通过Beverton-Holt模式估算出蓝圆鲹目前的持续产量为9.58×10~4t,最佳最小捕捞叉长为135mm。     

闽南-台湾浅滩表层沉积物中底栖有孔虫分布及其环境特征

本文分析了闽南-台湾浅滩表层沉积物样品中的底栖有孔虫计有132属、328种。根据种类组成及分布特征,可将海区划分为6个动物群区,每个动物群区各有自己的环境特点。文中分析了动物群种类组成特征与其所赋存的环境之间的关系,并讨论了浅滩西南303站底栖有孔虫的分布与上升流的关系。     

The Hatton Bank continental margin—I. Shallow structure from two-ship expanding spread seismic profiles

Summary. The Hatton Bank passive continental margin exhibits thick seaward dipping reflector sequences which consist of basalts extruded during rifting between Greenland and Rockall Plateau. Multichannel seismic reflection profiling across the margin reveals three reflector wedges with a maximum thickness near 7 km, extending from beneath the upper continental slope to the deep ocean basin. We present results of the velocity structure within the dipping reflector sequences at eight locations across the margin, interpreted by synthetic seismogram modelling a set of multichannel expanding spread profiles parallel to the margin. At the top of some reflector sequences, we observe a series of 100 m thick high- and low-velocity zones, which are interpreted as basalt flows alternating with sediments or weathered and rubble layers. At the profile locations, the base of the dipping reflectors correlates with P -wave velocities near 6.5 km s⁻¹. However, elsewhere the reflectors appear to extend significantly deeper than the inferred 6.5 km s⁻¹ velocity contour, indicating that the velocity structure may not be controlled solely by lithological boundaries but also by metamorphic effects. Shear-waves were observed on two lines, permitting the calculation of Poisson's ratio. The decrease in Poisson's ratio from 0.28 to near 0.25 in the upper 5 km of crust may also indicate the effect of metamorphism on seismic properties, or alternatively may be explained by crack closure under load.     

石林世界地质公园旅游发展的SWOT分析及对策

石林世界地质公园旅游发展中并存优势和劣势、机遇和威胁。为实现公园旅游的可持续发展，笔者用SWOT方法对石林世界地质公园旅游的发展进行分析，并在此基础上提出相应对策。     

世博经济圈形成基础和机制研究

会展旅游全球性的迅速发展归因于相关的预期经济利益,以及带给旅游目的地的社会、文化、技术等无形利益.2010年上海世博会的举办将对长江三角洲乃至中国产生深远的影响.首先分析了世博经济特征和效应.其次,探讨了世博经济圈的形成基础,认为世博经济圈可以被描述为一个多层面(区域、城市和公司)相互联系的城市网络,世博经济圈的形成必须拥有良好的空间结构和组织结构;最后对世博经济圈的形成机制进行了初步研究,提出区域合作机制的创新和完善是世博经济圈形成的重要动力,经由制度创新、文化协调、区域管治,推动要素的优化配置和利益主体的融合实现区域共生;通过核心城市的进一步中心化和节点城市的专业化实现更加分散和互补的发展.     

Transaction links through cities: ‘decision cities’ and ‘service cities’ in outsourcing by leading Brazilian firms

Most world city studies focus on where the provision of advanced producer services takes place, but in this study the location of the service clients are also taken into account. Production-service transactions are identified as links between ‘service city’ and ‘decision city’ (client HQ) and classified as intra-city (where a firms uses local (same city) services) and inter-city which may be domestic or foreign depending on whether the client uses services in or out of the country. Sampling the leading firms in Brazil, 218 transaction links are described and analysed in terms of cities, firm sectors, ownership and market. The analyses are used to inform a rereading of gateway city functions that takes into account the concentration/dispersal nexus in economic globalization. Thus, whereas the dominance of Sao Paulo in the Brazilian economy is confirmed, this is not interpreted as a simple gateway function with this one city ‘articulating’ the national economy into the world economy. A much more complex situation is revealed with by-passing of the gateway also much in evidence. The conclusion is that this shows concentration and dispersion of economic activity happening simultaneously in Brazil.     

Influence of Climate Change on Winter Wheat Growth in North China During 1950-2000

1. IntroductionChinese agriculture has undergone tremendousstructural changes over the last decades. The averagestaple crop productivity has doubled in 25 yr while thepopulation increased by 25 % [China Statistical Year-book (CSY), 2003]. Winter wheat is one of China'smost important staple food crops, with a total farm-ing area of nearly 24 million hectares and a produc-tion exceeding 92 million ton in 2002 (CSY, 2003).Although China has been the world's largest wheatproducer since 1983 (…