Winter mortality risk for American ginseng (Panax quinquefolium) in Saskatchewan

North American ginseng is native to the deciduous forest region of eastern North America but is now cultivated in areas well beyond its natural range. In recent years an expanding market has attracted growers in climatically less suitable regions, including the Canadian prairies. The ginseng root requires at least four years to reach marketable size and is sensitive to injury when the temperature drops below about −4°C. Such temperatures are not unusual in the prairies; thus winter kill is a hazard that may limit ginseng production in this region of Canada. This study analyses the risks of winter soil temperatures falling below levels critical for the survival of ginseng in Saskatchewan. It appears that winter conditions may be too severe for reliable production of this lucrative crop, although application of straw mulch and additional benefits of trapped snow could reduce the risk of winter kill.     

Street names and the scaling of memory: the politics of commemorating Martin Luther King, Jr within the African American community

Streets named for Martin Luther King, Jr are common yet controversial features in cities across the United States. This paper analyses the politics of naming these streets as a 'scaling of memory'– a socially contested process of determining the geographic extent to which the civil rights leader should be memorialized. Debates over the scaling of King's memory revolve around the size of the named street, the street's level of prominence within a hierarchy of roads, and the degree to which the street transcends the spatial confines of the black community. A street-naming struggle in Eatonton, Georgia (USA) exposes how the scaling of memory can become a point of division and contest within the black community as activists seek to fulfil different political goals. Analysing these intra-racial contests allows for a fuller appreciation of the historical consciousness and geographic agency of African Americans rather than seeing them as a single, monolithic group.     

美国大学区域地理教育的发展与变迁--以亚洲地理教育为例

区域地理是地理学教育与研究的一个重要组成。在当今经济与环境的全球化过程中,对区域地理课程的需求有了明显上升。区域地理教育的重要性也引起了方面的重视。美国大学区域地理教育的发展与变迁主要受两方面的影响：一是地理教育在国民教育中的地位;二是某个区域在国际事务中的重要性以及与美国的关系。在过去３０年中,随着近年来亚洲经济的高速发展和它在国际中的地位日益提高,以及亚洲与美国贸易额的的迅速增长,亚洲地理课在     

美国基础设施状况和重建计划

2018年2月发布的《美国重建基础设施立法纲要》是近年来美国在基础设施领域的重大改革之一,将对美国乃至世界基建投资、新技术普及、城乡发展产生深远影响。论文基于相关文献和资料,总结了美国基础设施落后的状况,从资金分配入手探讨了“重建计划”内在逻辑,并针对其可行性进行了分析,得出以下几点启示：有针对性、特定领域的基建投资仍是实现高质量发展的重要工具;地方政府与私营部门进入国家基建领域具有积极意义;基建计划的金融化、杠杆化不可避免,但需严防其过度;基建投资在短期上对低技术岗位有明显带动作用。     

'After-the-fact causality': a different direction for cultural geography

Cultural geography might benefit from consideration of radical behaviourism and from interpretation and application of the concepts of behaviour analysis. The basic concept is that of operant conditioning, referring to the environment reinforcing behaviours that are most adaptive and effective in achieving reinforcers and avoiding aversive stimuli. The concept of rule-governed behaviour facilitates incorporation of cognition into behaviour analyses, accommodating the fact that many consequences are delayed. These concepts are applied in an analysis of nineteenth-century Mormon settlement in the American West. This argument for an objectivist approach is laden with social scientific baggage not favoured in contemporary cultural geography.     

Hard times in Apia? Urban landlessness and the church in Samoa

This paper presents findings from a study about the relationships between social change and settlement change in Samoa, where a form of landlessness is emerging in low income areas of the main town, Apia. It examines changing reciprocal kinship arrangements with respect to customary rural village plantation land and changes in both individual and household relationships with the church. Although these relationships are typically closely bound in Pacific island societies, recent field‐based research has revealed the expansion of landless urban settlements with households that are alienated from rural village‐based kin and, by extension, customary land.     

BOOK REVIEWS

Book Reviewed in this article: The Vanishing Farmland Crisis, Critical Views of the Movement to Preserve Agricultural Land . John Baden Protecting Farmlands . Frederick R. Steiner and John E. Theilacker Ecological Effects of Fire in South African Ecosystems . Peter de V. Booysen and Neil M. Tainton Geography in China . Wu Chuanjun , Wang Nailiang , Lin Chao and Zhao Songqiao Resource Inventory and Baseline Study Methods for Developing Countries . Francis Conant , Peter Rogers , Marion Baumgardner , Cyrus Mc Kell , Raymond Dasmann, and Priscilla Reining Principles of Remote Sensing . Paul J. Curran Famine As A Geographical Phenomenon . Bruce Currey and Graeme Hugo The Suburban Squeeze: Land Conversion and Regulation in the San Francisco Bay Area . David E. Dowall Senses of Place . John Eyles Uneven Development and the Geographical Transfer of Value . D. K. Forbes and P. J. Rimmer Issues in Wilderness Management . Michael Frome Land-use and Prehistory in South-east Spain , The London Research Series in Geography 8. Antonio Gilman and John B. Thornes with Stephen Wise Regions in Question, Space, Development Theory and Regional Policy . Charles Gore The Colorado River: Instability and Basin Management . William L. Graf Hazardous Waste Sites: The Credibility Gap . Michael R. Greenberg and Richard F. Anderson Peasants, Subsistence Ecology, and Development in the Highlands of Papua New Guinea . Lawrence S. Grossman Silver Cities: The Photography of American Urbanization, 1839-1915 Peter B. Hales Silicon Landscapes . Peter Hall and Ann Markusen Remaking Ibieca: Rural Life in Aragon under Franco . Susan F. Harding The European Energy Challenge: East and West . George W. Hoffman The Global Climate . John T. Houghton The Urban Jobless in Eastern Africa . Abel G. M. Ishumi . The Tourist: Travel in Twentieth-Century North America . John A. Jakle City and Society: An Outline for Urban Geography . R. J. Johnston Residential Segregation, The State and Constitutional Conflict in American Urban Areas . R. J. Johnston Accessibility and Utilization: Geographical Perspectives on Health Care Delivery . Alun E. Joseph and David R. Phillips To the Heart of Asia: The Life of Sven Hedin . George Kish North American Culture , Vol 1. Ary J. Lamme III Past and Present in the Americas: A Compendium of Recent Studies . John Lynch Ethnicity in Contemporary America: A Geographical Appraisal . Jesse O. Mc Kee The Shell Countryside Book . Richard Muir and Eric Duffey 1990 Planning Conference Series. Proceedings of the National Geographic Areas Conference . Proceedings of the Regional Geographic Areas Conferences Wood, Brick, and Stone: The North American Settlement Landscape . Vol. 2: Barns and Farm Structures . Allen G. Noble Bangladesh: Biography of a Muslim Nation . Charles Peter O'donnell     

Compositional variations of Cretaceous pumpellyites along the western margin of South America and their relation to an extensional geodynamic setting

Abstract Pumpellyites in pervasively altered basic to intermediate rocks from three Cretaceous Andean volcanic sequences, the Colombian Diabasic Group, the Ecuadorian-Peruvian Celica Formation/Casma Group and the Chilean Ocoite Group, were studied to test their compositional behaviour in relation to changes in geodynamic setting. They occur mostly in assemblages of the prehnite-pumpellyite facies filling amygdules and inside plagioclase phenocrysts.
(a) Pumpellyites from the three geodynamic settings define three distinct compositional fields in AFM space: (i) those in the Diabasic Group plot closer to the Fe corner; (ii) those in the Ocoite Group plot closer to the Al corner; (iii) those in the Celica Formation/Casma group plot between, and partly overlapping, fields (i) and (ii).
(b) Pumpellyites in group (i) formed in T-MORB like, K-poor tholeiites (high Fe/Al), affected by ocean-floor metamorphism in an oceanic back-arc basin. Pumpellyites in group (ii) generated in K-rich, calc-alkaline (low Fe/Al) to shoshonitic metabasites affected by burial metamorphism in an ensialic, aborted, marginal basin with moderate attenuation of the continental crust. Pumpellyites in group (iii) formed in basic and intermediate, calc-alkaline to tholeiitic rocks, metamorphosed in ensialic marginal basins with various degrees of continental crust thinning, from splitting to moderate attenuation. A correlation between pumpellyite and host-rock composition is suggested by these characteristics.
(c) Pumpellyites in prehnite-pumpellyite facies assemblages of some of the units studied plot inside higher (and lower) grade reference fields (AFM space) corresponding to different geodynamic settings elsewhere. This anomaly is attributed to the changing characteristics of the marginal basins at the South American margin and emphasizes the need to compare equal facies referred to equal settings.     

旅华美国游客目的地城市色彩意象认知研究

色彩是旅游目的地意象的重要外显形式与构成,其虽被广泛应用于旅游目的地建设与发展,但其理论研究在国内外几近空白.本文以旅华美国游客为研究对象,以旅游目的地城市色彩意象认知为研究内容,通过10 批次全程客流跟踪的调研方式获取了研究资料,运用扎根理论构建了旅华美国游客的目的地城市色彩意象认知维度模型,并通过二次定点调研方式对本研究的理论饱和度进行了检验.研究结果表明：① 旅游目的地城市色彩意象认知的主要影响因素为城市色彩基调与建筑、旅游吸引物、人际影响、差异性文化感知、旅游经历、旅游目的地人文与自然环境;② 目的地城市色彩意象认知由视觉色彩和理念色彩两部分构成;③ 游客的个人偏好和旅游情感会直接作用于旅游目的地城市色彩意象认知,并直接导致游客产生行为意图;④ 游客的目的地城市色彩意象认知会刺激并促使游客产生行为意图.本文讨论中提出了旅游目的地城市色彩意象认知加工的发生机制与过程模型.