Differentiating Between Subsystems and Typologies in the Analysis of Migration Regions: A U.S. Example*

Studies of migration regions are characterized by two separate conceptual approaches. The first views migration regions as clusters of highly interconnected spatial units (subsystems) while the other defines them as groups of spatial units with a similar geographic structure of flows (typologies). This paper highlights the theoretical and methodological distinctions between migration subsystems and typologies. An empirical analysis using U.S. migration data for 1940, 1960, and 1980 shows that although migration subsystems and typologies have both changed over time, each reveals a different dynamic of regional change and has different morphological characteristics.     

美国本土的外国投资与投资环境的地区差异

本文论述了美国的外国直接投资额、外国直接投资密度和外国直接投资年增长率的地区差异，并用这三个数量指标来综合评价各州投资环境的优劣，按综合得分值的高低将美国本土划分为四类区域：Ⅰ类投资环境区、Ⅱ类投资环境区、Ⅲ类投资环境和Ⅳ类投资环境区。     

Identifying Skill Requirements for GIS Positions: A Content Analysis of Job Advertisements

This study identifies the skill requirements for geographic information system (GIS) positions, including GIS analysts, programmers/developers/engineers, specialists, and technicians, through a content analysis of 946 GIS job advertisements from 2007–2014. The results indicated that GIS job applicants need to possess high levels of GIS analysis and modeling skills (e.g., database development) and personal and social skills (e.g., communication) to obtain employment, although specific skill requirements differed significantly depending on job title. The findings from this study may be useful for improving GIS majors’ employability.     

美国波士华交通经济带的形成与演化

本文研究了美国波士华交通经济带的形成与演化过程，分析了在不同阶段美国波士华交通经济带的生命周期特征，认为美国商业资本主义、产业资本主义的发展、高速公路的发展以及带来的集聚与扩散作用、经济服务化分别在美国波士华交通经济带的形成、发展和演化等不同阶段扮演着重要角色。波士华交通经济带是美国最大、发展最早的交通经济带，研究该地区的演化规律对我国交通经济带发展也具有借鉴作用。     

美国外资R&D的空间集聚特征

本文考察美国境内的715家外资R＆D机构的空间分布和集聚现象,发现美国的外资R＆D机构高度集中在三类地区;一是以硅谷和研究三角园区为代表的科技园区,二是纽约等经济中心城市,三是以底特律为代表的专业化工业城市。不同地区的外资R＆D机构的行业结构与当地的优势行业完全一致,如硅谷的外资R＆D机构主要是从事计算机技术的研发,底特律的外资R＆D全部是从事汽车工业或与之有关技术的研发,纽约、洛杉矶和芝加哥的外资R&D机构所从事的行业则呈现与各城市优势行业一致的多样性。     

Organizational Dynamics of the U.S. Logistics Industry: An Economic Geography Perspective*

Although the logistics industry provides critical services to all sectors of the economy, few studies exist in economic geography that examine and explain the organizational dynamics of this industry. This article highlights the significance of the logistics industry in contemporary industrialization and argues that an enriched understanding of the interaction between technology and space can be achieved by examining the evolution of an industry that plays a central role in the contemporary economy. We focus on dimensions that are identified as particularly important: organizational, geographic, and risk and security.     

美国铁路网的形成、分布和改造

本文分析了美国铁路网迅速形成和急剧缩减的原因，指出其非均衡分布的特点，介绍其远景改造设想，对我国铁路网的建设有一定的参考价值。     

美国海岸带综合管理及其对我国的借鉴意义

1972年美国颁布了世界上第一部综合性的海岸带管理法规－《海岸带管理法》，标志着现代海岸带综合管理的开端，在回顾美国海岸带综合管理发展的基础上，从海岸带管理立法与政策、管理形式、体制和公众参与等4个方面概括了美国海岸带综合管理的主要特点，最后，针对我国在进行海岸带综合管理试验中面临的问题，提出了若干建议。     

美国国家公园志愿者服务及机制——以海峡群岛国家公园为例

具有百余年历史的美国国家公园志愿者服务已成为美国国家公园管理的重要部分,志愿者服务有效实现了美国国家公园的全民管理思路。通过实地考察和访谈记录梳理,就国家公园志愿者服务的相关概念、服务动机、服务决策、服务内容、服务支持和服务机制深入剖析,从庞大有序的服务系统、管理与运行、功能实现三方面分析国家公园志愿者服务机制;提炼出美国国家公园志愿者服务的四个支持：宣传支持、技术支持、学习支持和立法支持。并以美国海峡群岛国家公园为例进行论证。最后提出国家公园志愿者服务和中国国家公园志愿服务尚需研究的诸多内容,任重而道远。     

美国出口管制下中国外贸风险的省域地理差异

从总贸易、出口、进口、外资和人员5个视角构建对美风险系数,测度和比较各省区市对美外贸风险的地理差异。结果表明:上海、浙江和福建与美国的进出口贸易规模最大,对美国市场的依赖程度最高,面临的综合外贸风险最大;河南尤其需要防范对美国的出口风险;海南、新疆、天津和西藏等需要加强从美国进口的风险管理;重庆除了需要防范对美出口风险外,还因为实际利用美资最多且依赖程度最大,亟需加强外资风险管理。宁夏和山西虽然从美国的引资规模不大,但是对美资的依赖程度最高,亟需提升外资多元化水平。从人员跨境流动风险来看,上海、北京和浙江面临的风险最大。中国各省区市在应对美国出口管制时应该加强外贸风险的识别和管理,针对不同的风险采取差别化的防范和化解措施。     

Spatio-temporal changes in heat waves and cold spells: an analysis of 55 U.S. cities

With observed increases in global temperatures indicating changes to anomalous temperature events (ATE), few studies have considered the changes associated with both heat and cold together. This study evaluates the changes in heat waves and cold spells for 55 U.S. metropolitan areas (1948–2012). Using surface observations, thresholds of mean apparent temperature were used to define heat, extreme heat, cold, and extreme cold events. Days that exceeded the 95th temperature percentile were considered heat days. Similar values were used to define extreme heat (97.5th), cold (5th), and extreme cold (2.5th). Thresholds were calculated independently for each of the locations, incorporating spatial variability into the ATE definition. Changes in duration, seasonal timing, and frequency, all of which have been shown to be important characteristics in regard to heat and cold events, were evaluated. Significant changes in some characteristics were found. Across many locations, heat events have become more frequent, longer lasting, and earlier occurring, while cold spells have experienced an opposite trend. Since heat and cold events impact a range of ecological and bioclimatological processes, understanding the variability and changes associated with ATE remains an important aspect to consider as society prepares for future events.     

Population Change in U.S. Cities: Estimating and Explaining the Extent of Decline and Level of Resurgence

The revalorization of the U.S. metropolis and restructuring of the U.S. economy are leading to increasingly complex patterns of population growth and decline. In this article we provide an empirical context for understanding the embodied nature of these changes by analyzing the long-term, demographic changes for the 100 largest cities. In terms of population change we identify four model urban types: steady decline, continuous increase, growth interrupted, and slowly resurgent. We consider, in detail, cities where population decline has halted and others where there are indications of population resurgence. The article focuses on these resurgent cities, provides some causal explanations, discusses the role of gentrification, and explores policy implications.     

Vibrant Centers as Locations for High-Growth Firms: An Analysis of Thirty U.S. Metropolitan Areas

What kinds of places have high entrepreneurial activities? There has been an emerging body of studies about so-called entrepreneurship ecosystems, but virtually all of the past studies have examined this question from a perspective of which metropolitan areas have higher entrepreneurial activities. In this article, we examine the intrametropolitan scale at the Census tract level. By analyzing thirty metropolitan areas to extend external validity, we demonstrate the concentration of high-growth firms in specific employment nodes in both urban and suburban parts of each metropolitan area. Significant correlations exist between place-based vibrancy indicators and high-growth firm concentrations.     

A comparison of state space and multiple regression for monthly forecasts: U.S. Fuel consumption

Monthly consumption forecasts for U.S. oil, natural gas, and coal are made using state space and multiple regression applied to the same data. These forecasts are compared with actual consumption for a test period. The forecasts made using state space are preferred to those made using multiple regression models for both expost and exante cases. The state space forecasts track data cycles better than do the regression forecasts. Average absolute forecast errors are less for the state space models than they are for the multiple regression models.     

经济形态演变对海洋海岛生态环境的影响——以美国海峡群岛为例

海洋海岛生态环境脆弱,一旦遭受破坏难以修复。人类社会历经原始经济时代、农业经济时代、工业经济时代和知识经济时代,经济形态的演变影响着人类生存的生态环境。以美国海峡群岛为例,以时间和事件两个维度对海岛生态环境破坏、生态修复和环境保护进行梳理,侧重于知识经济时代在国家公园管理局管理下的生态修复和环境保护。其中信息知识、生态文明、高新技术是海峡群岛实现生态回归的重要因素。海峡群岛的发展历程和后期的生态修复与管理为其他国家海洋海岛经济发展提供借鉴。