共查询到20条相似文献，搜索用时 109 毫秒
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《The Professional geographer》2013,65(3):296-297
Edward Jarvis in 1850 first demonstrated that admission rates to mental hospitals decrease with increasing residential distance, a relationship known today as “Jarvis's Law.” His original data are presented, mapped, and examined by regression analysis to better understand spatial and temporal patterns of mid-19th century mental hospital utilization. Distance substantially affected admission rates to a radius of about 60 miles from the institution in Massachusetts; and there was strong distance decay in the other states examined. For all twelve states, there was a positive association between age of the hospitals and admission rates, which also decreased with increasing residential distance. 相似文献
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《The Journal of geography》2012,111(9):555-560
Abstract Figures from the 1970 Soviet Census provide an abundance of information on population changes in the U.S.S.R. Of special note is the process of urbanization and a noticeable concentration of urban growth in the hitherto largely rural zones of western Russia. A large map of urban places in 1970, designed primarily for classroom use, accompanies the text (see inside back cover). The map utilizes a special stippled-sphere technique to allow a three-dimensional effect without half-tone reproduction. 相似文献
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《The Professional geographer》2013,65(4):379-385
Bedrock forms of etch origin result from the interaction of groundwaters and bedrock at the weathering front at the base of the regolith. They are significant for general theories of landscape and landform genesis because they are azonal with respect both to climate and lithology. Two stages of etch form development are recognized: one involves weathering and the formation of a regolith; the second consists of stripping of the regolith and the exposure of the bedrock forms. Although etch forms have been recognized for some two centuries, the concept of etching as a process of landform development has been neglected, particularly in North America. 相似文献
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Kingkade WW 《Soviet geography》1988,29(4):394-412
"This report presents the results and assumptions of a set of projections of the population of the USSR, 1979-2025. Trends in population size and age-sex composition as well as fertility, mortality, and emigration are discussed.... The projections show that the population of the USSR will grow throughout the period to 2025. The working age population will grow very slowly for at least the next 10 years, and will not recapture the rapid growth experienced in the 1970s. The pension-age population will double in size between 1980 and 2025." 相似文献
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Natural Resources Research - 相似文献
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近50年来兰州城市气候变化的R/S分析 总被引：37，自引：7，他引：37
运用R／S方法、城效对比法，对1951－1999年兰州市城市气候的温度、水汽压、相对湿度和日照百分率等指标的冬（1月）、夏（7月）及年平均值进行了计算分析，各项指标的Hurst指数H均大于0.5，说明它们存在明显的赫斯特现象，反映了兰州市近50年来气候变化存在趋势性成分，即持续性的城市化气候效应。至于各项指标的Hurst指数在冬、夏及年平均值间有差异，分析证明这是兰州城市化气候效应强度的季节差异所造成。 相似文献
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应用R/S方法分析NDVI时间序列 总被引：4，自引：1，他引：3
针对1982--2001年月合成PALNDVI时间序列,应用R／S方法计算中国陆地范围内的赫斯特指数。结果表明：全国范围内的赫斯特指数普遍大于0．5,意味着NDVI时间序列不是马尔科夫序列,而是存在明显的趋势性;中国陆地范围内的赫斯特指数分布存在“西高东低”的特点,说明西部NDVI时间序列表现出更强的持久性;通过分析赫斯特指数分布与陆地覆盖类型的关系发现,在同一生态地区内,裸地的赫斯特指数最高,与其它覆盖类型差异明显。陆地覆盖类型之外的自然条件和人为因素对赫斯特指数空间分布的影响有待进一步研究。 相似文献
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