城市职能演变的回顾与展望

全球化是当前世界发展的主流,全球化对城市的发展已经产生了深远的影响,一方面生产要素在城市之间的流动加强。另一方面城市主导权力扩大。加剧了城市之间的竞争。由此带来城市产业结构和产业布局的变化,促进了城市化、郊区化、绅士化等的发展。在此背景之下,全球城市在人类社会发展中的职能不断演变。其基本趋势是由生产性职能转向服务性职能。并且这种演变会伴随着全球信息化的发展逐步由多元服务向单一的人居服务发展。本在对全球城市职能演变简单回顾的基础上。根据全球化发展的趋势。探讨了全球化对城市职能演变的影响,并预测未来城市职能的变化趋势。     

An uninhabited waste: transforming the Grand Prairie in nineteenth century Illinois, USA

Today the area once known as the Grand Prairie in the American Midwest is best known for its high agricultural productivity and monoculture. Little of the original prairie landscape that gave the region its name remains. Prior to white settlement, the region was perceived as swampy, dangerous, unhealthy and unfit for agriculture. This ‘uninhabited waste’ and ‘giant emporium of malaria’ embodied the type of landscapes settlers initially tried to avoid. Ultimately, perceptions of the Grand Prairie landscape as well as the physical landscape itself were altered by settlement and improving drainage technology. This paper aims to link changes in the way the central Illinois landscape was imagined and perceived, with the subsequent environmental transformation that resulted in the near total elimination of tallgrass prairie and the wholesale alteration of regional hydrology through channelization and agricultural drainage.     

Enacting power through networks

We argue here that processes of political centralization and hierarchy building can be profitably explored by focusing on how resources were strategically manipulated in search of power by people organized in social networks of varying sizes and spatial extents. Adopting this perspective encourages reconsideration of the ways in which such core concepts as structure, agency, and society can be redefined to cast new light on ancient power contests. In addition, we suggest that a network approach complements traditional emphases on processes of domination and resistance by drawing attention to the importance of alliances in shaping political formations. The potential utility of these precepts is illustrated in an example drawn from our research on Terminal Classic (800–1000 AD) political struggles in the Naco valley of northwestern Honduras. Special attention in this case centers on the manner in which craft products were manipulated by people of varying ranks to define and achieve goals as well as to control the actions of others. The study’s broader implications for the analysis of ancient political relations are highlighted at the essay’s conclusion.     

长春-吉林经济带的形成与空间结构特点研究

文章通过对经济带概念的分析,构建经济带的形成和演进理论,认为经济带有等级、层次之分,其时空演进的理论为增长极理论——点一轴发展理论——梯度推移理论。在此基础上,论证长春—吉林经济带的存在性,分析其结构、功能及空间联系形式。作者认为,长春—吉林经济带目前是一个弱经济带,其扩散效应较弱,随着其扩散效应的增强,长春—吉林经济带将能够从整体上带动和促进吉林省的经济发展。     

The power of precision air strikes and social media feeds in the 2012 Israel–Hamas conflict: ‘targeting transparency’

This article analyses the evolving uses of social media during wartime through the IDF (Israel Defense Forces) Spokesperson Facebook and Twitter accounts. The conflict between Israel and Hamas-affiliated groups in November 2012 has generated interesting data about social media use by a sovereign power in wartime and the resultant networked discourse. Facebook data is examined for effective patterns of dissemination through both content analysis and discourse analysis. Twitter data is explored through connected concept analysis to map the construction of meaning in social media texts shared by the IDF. The systematic examination of this social media data allows the authors’ analysis to comment on the evolving modes, methods and expectations for state public diplomacy, propaganda and transparency during wartime.     

Optically stimulated luminescence dating of young fluvial deposits of the Middle Elbe River Flood Plains using different age models

In the last few decades optically stimulated luminescence (OSL) dating has become an important tool in geochronological studies. The great advantage of the method, i.e. dating the depositional age of sediments directly, can be impaired by incomplete bleaching of grains. This can result in a scattered distribution of equivalent doses (D_E), leading to incorrect estimation of the depositional age. Thoroughly tested protocols as well as good data analysis with adequate statistical methods are important to overcome this problem. In this study, samples from young fluvial sand and flood plain deposits from the Elbe River in northern Germany were investigated to compare its depositional ages from different age models with well-known historical dates. Coarse grain quartz (100–200 μm and 150–250 μm) and polymineral fine grains (4–11 μm) were dated using the single aliquot regenerative (SAR) dose protocol. The paleodose (D_P) was calculated from the DE data set using different approaches. Results were compared with the development of the Elbe River, which is well-documented by historical records and maps covering the last 1,000 years. Depending on the statistical approach it can be demonstrated that depositional ages significantly differ from the most likely depositional age. For the investigated coarse grain quartz samples all ages calculated from the MAM-3_UL, including their uncertainties, are within the historical documented age. Results of the polymineral fine grain samples are overestimating the historically documented depositional age, indicating undetectable incomplete bleaching. This study shows the importance of using an adequate statistical approach to calculate reliable OSL ages from fluvial sediments.     

Ground‐Penetrating Radar Velocity Determination and Precision Estimates Using Common‐Midpoint (CMP) Collection with Hand‐Picking,Semblance Analysis and Cross‐Correlation Analysis: A Case Study and Tutorial for Archaeologists

The most crucial parameter to be determined in an archaeological ground‐penetrating radar (GPR) survey is the velocity of the subsurface material. Precision velocity estimates comprise the basis for depth estimation, topographic correction and migration, and can therefore be the difference between spurious interpretations and/or efficient GPR‐guided excavation with sound archaeological interpretation of the GPR results. Here, we examine the options available for determining the GPR velocity and for assessing the precision of velocity estimates from GPR data, using data collected at a small‐scale iron‐working site in Rhode Island, United States. In the case study, the initial velocity analysis of common‐offset GPR profile data, using the popular method of hyperbola fitting, produced some unexpectedly high subsurface signal velocity estimates, while analysis of common midpoint (CMP) GPR data yielded a more reasonable subsurface signal velocity estimate. Several reflection analysis procedures for CMP data, including hand and automated signal picking using cross‐correlation and semblance analysis, are used and discussed here in terms of efficiency of processing and yielded results. The case study demonstrates that CMP data may offer more accurate and precise velocity estimates than hyperbola fitting under certain field conditions, and that semblance analysis, though faster than hand‐picking or cross‐correlation, offers less precision.     

Localized mobility clusters: impacts of labour market externalities on firm performance

This article analyses the impact of labour market-induced externalitieson firm performance by using a unique database that connectsattributes of individuals to workplaces for the entire Swedisheconomy. Based on the analysis of 256,985 workplaces, our resultsshow that firms belonging to networks of local job mobility(i.e. ‘localized mobility clusters’) significantlyoutperform other similar firms within the local labour market.The results also indicate that concentrations of similar andrelated firms do not explain any considerable part of the variationsin firm competitiveness. Labour market externalities derivedvia local job mobility produce significantly more powerful effectsfor the involved firms as compared to the degree of co-location,diversity and scale.