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地理学家的演讲与他们运用文字、图象所作的交流同样值得重视.美国的地理学可以通过下述途径得到加强,即围绕地点、地区和全球联系发展实质性演讲,促进自然地理的发展,恢复地理生态的传统.地理信息系统(geographic information systems)对于完成上述任务,对于改进地理学科以满足不断出现的需要,将是一个非常有用的工具.如果我们能够避免自己拆自己的台,避免不现实的空想,避免玩弄语言技巧,而是坚持在大学里进行高质量的教学,并在教师和从事地理实践工作的人员之间开展学术交流,那么地理学将会变得更加有效.我们有一个前所未有的机会来帮助改进美国的中小学地理教育.  相似文献   
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The reasons why the Western Mediterranean, especially Carthage and Rome, resisted monetization relative to the Eastern Mediterranean are still unclear. We address this question by combining lead (Pb) and silver (Ag) isotope abundances in silver coinage from the Aegean, Magna Graecia, Carthage and Roman Republic. The clear relationships observed between 109Ag/107Ag and 208Pb/206Pb reflect the mixing of silver ores or silver objects with Pb metal used for cupellation. The combined analysis of Ag and Pb isotopes reveals important information about the technology of smelting. The Greek world extracted Ag and Pb from associated ores, whereas, on the Iberian Peninsula, Carthaginians and Republican‐era Romans applied Phoenician cupellation techniques and added exotic Pb to Pb‐poor Ag ores. Massive Ag recupellation is observed in Rome during the Second Punic War. After defeating the Carthaginians and the Macedonians in the late second century bce , the Romans brought together the efficient, millennium‐old techniques of silver extraction of the Phoenicians, who considered this metal a simple commodity, with the monetization of the economy introduced by the Greeks.  相似文献   
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The standard theory of optimal jurisdictional size hinges on the existence of economies of scale in the provision of local public goods and services. However, despite its relevance for forced local amalgamation programs and related policies, the empirical evidence on the existence of such economies of scale remains elusive. The main goal of this paper is to produce an updated and comprehensive quantitative review of the existence of economies of scale in the provision of local public goods using a meta-analysis approach to systematize the wide range of empirical approaches and modeling frameworks found in the previous literature. Our analysis confirms the presence of moderately increasing to constant returns to scale in the provision of local services with no reduction in the average costs of production in the delivery of most local public services beyond a certain, modest jurisdictional size, which many studies have estimated at 10,000 residents. Also, the potential for economies of scale differs at least across three traditional services: education, water and sanitation, and garbage collection, being highest for education and lowest for garbage collection. Our analysis also offers guidelines for future empirical research in this area. Physical output and production cost data should be used, together with translog specifications for the modeling of cost functions. Last, we find evidence that the determinants of output cost elasticity include bidirectional publication bias and population density but do not include the presence or absence of modern “lean” production technologies or the (perceived) capital intensity of the sector, contrary to conventional wisdom. These findings have significant policy implications for countries considering jurisdictional consolidation programs.  相似文献   
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In this paper, we develop a three-region economic geography model with workers of heterogeneous skills and mobility rates to consider how first-nature, regional differences impact both inter- and intraregional inequality. In our model, the skill premium within a region summarizes both the degree of intraregional inequality between mobile, skilled workers and immobile, unskilled workers and the interregional inequality through differences in the welfare of unskilled workers across regions. Regions with the highest skill premium have the greatest degree of intraregional inequality and provide the lowest level of welfare to unskilled workers, relative to other regions. We find that the skill premium will be higher in regions with a greater supply of unskilled labor, lower supply of housing, or are more remote. An increase in a region's housing supply or centrality will lower intraregional inequality and raise the welfare of the local, unskilled workforce. However, the magnitude of these changes are declining in the initial number of skilled workers in the region. The model is extended to consider imperfectly elastic housing supply. The larger the price elasticity of housing, the larger the range of values, such that more populated regions will host a disproportionate share of skilled workers, have lower levels of intraregional inequality, and provide higher levels of welfare for unskilled workers.  相似文献   
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A major theme of current archaeological research in the Middle Atlantic region of Eastern North America is the recognition of cultural variability across space and through time. The most significant culture change experienced during the entire time frame of regional prehistory occurred ca. 5000 B.P., when there were major changes in regional environments. Before 5000 B.P., adaptations were characterized by small groups of mobile hunters and gatherers. After 5000 B.P., there were continued growth in regional populations and increases in sedentism, intensive use of a limited range of food resources, social group size, and social complexity.  相似文献   
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