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Foggin PM 《Singapore journal of tropical geography》1983,4(1):11-24
This paper focuses on whether there is an organized structural pattern in the spatial distribution of oral contraceptive usage in rural Thailand and, if so, how this spatial pattern is linked to other related socioeconomic variables. The data concern the year 1975. The results suggest that the location of the health services infrastructure seems to have the most significant effect on the differences in level of oral contraceptive use observed. 相似文献
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由广东省地质学会、广东省地震学会和地理学会联合主办的“华南沿海海滩岩与第四纪环境研讨会“于1988年1月21日至24日在广东省汕头市召开。出席大会有来自全国各地12个单位32名专家和代表。会议收到论文摘要24篇,我所刘以宣、朱袁智、陈欣树、潘新虎、李赶先等参加了这次会议。刘以宣,朱袁智在会上宣读了论文,提出对东南沿海全新世碳酸盐胶结碎屑岩的划分与广澳风坡积碎屑岩的成因等新观点,受到与会代表的重视。 相似文献
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Polyan PM 《Soviet geography》1982,23(10):707-718
The study of urban agglomerations in the USSR is discussed, with a focus on their basic framework and role in settlement and on the various techniques used to define such agglomerations. "The present paper envisages a minimum population of 250,000 for the core city (or cities), maximum travel time of 1.5 to 2 hours to the core city, and a minimum value for a 'development coefficient' reflecting the population of the agglomeration and its structure in terms of urban places. The networks of agglomerations that existed at the time of the 1959 and 1970 censuses are analyzed and compared. The urban agglomerations are grouped into five classes of development levels and into three classes of growth rates. Intensive and extensive growth factors are discussed." 相似文献
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Dissolved carbon monoxide (CO) is present in ground water produced from a variety of aquifer systems at concentrations ranging from 0.2 to 20 nanomoles per liter (0.0056 to 0.56 microg/L). In two shallow aquifers, one an unconsolidated coastal plain aquifer in Kings Bay, Georgia, and the other a fractured-bedrock aquifer in West Trenton, New Jersey, long-term monitoring showed that CO concentrations varied over time by as much as a factor of 10. Field and laboratory evidence suggests that the delivery of dissolved oxygen to the soil zone and underlying aquifers by periodic recharge events stimulates oxic metabolism and produces transiently high CO concentrations. In between recharge events, the aquifers become anoxic and more substrate limited, CO is consumed as a carbon source, and CO concentrations decrease. According to this model, CO concentrations provide a transient record of oxic metabolism affecting ground water systems after dissolved oxygen has been fully consumed. Because the delivery of oxygen affects the fate and transport of natural and anthropogenic contaminants in ground water, CO concentration changes may be useful for identifying predominantly anoxic ground water systems subject to periodic oxic or microaerophilic conditions. 相似文献