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101.
Almost half a century has passed since Jean Gottmann coined the term “Megalopolis” in reference to the almost continuously urbanized stretch of land spanning the East Coast of the United States from southern New Hampshire to northern Virginia. Because a disproportionate concentration of population resided in this Megalopolis, the northeastern core enjoyed an economic and cultural supremacy, and he termed the Megalopolis “The Main Street of the Nation.” By the later 1960s and 1970s, however, population migration patterns began to reflect the influence exerted by the emergence of a second national core centered on the large metropolitan areas along the Pacific Coast, especially those of the Los Angeles and Bay Area conurbations in California. Although of different character, this burgeoning concentration of population, economic activity, and cultural influence may reflect the development of a West Coast Megalopolis that could soon rival the original Megalopolis of the Northeastern Corridor. Today, the U.S. population distribution is largely a bicoastal one. This article documents the emergence of this bicoastal population distribution. Using historical census data and GIS technology, we present a number of novel ways to graphically portray and examine this population redistribution phenomenon. The United States is not unique in witnessing an increasing share of its inhabitants clustering in coastal zones. Current critical policy concerns about the worldwide vulnerability of coastal populations have focused the need for better coastal population estimates and better mapping methods for portraying population redistribution trends.  相似文献   
102.
ABSTRACT. Levels of alcohol consumption are a major public health issue. This study aims to gain a better understanding of how geographical patterns of religious affiliation in the United States relate to geographical patterns of alcohol consumption. We explored state‐level correlations between alcohol consumption and religious adherence. Although we found no statistically significant correlation between overall religious adherence rates and current or binge drinking rates, states with higher adherence rates were significantly more likely to have high proportions of binge drinking among current drinkers. Yet, regionally, we found a strong inverse correlation in the Southeast and a strong positive correlation in the Midwest and Northeast between adherence rates and current and binge drinking rates. These geographical differences were largely explained after stratifying by major religious denominational groupings. States with high Catholic adherence rates tended to have higher drinking rates, whereas states with high Evangelical Protestant adherence rates tended to have lower drinking rates. These findings suggest that the relationship between religion and alcohol may be denomination‐specific and challenge the lay perception that religious adherence per se is associated with less alcohol consumption and less excessive drinking among those who drink.  相似文献   
103.
Gold has played an important role in the settlement and economics of the United States. Commercial production from 24 states totaled more than 420 million troy ounces (13,000 metric tons) from 1804 through 1995. There were, no doubt, early undocumented discoveries by Native Americans, but the first records are those from the mid-1600's in the east and from the 1770's in the west. Commercial production began in 1804 in North Carolina and spread among several Appalachian states in the 1820's and 1830's as placer deposits were discovered and exploited. After peaking in the 1830's and 1840's, Appalachian production began to decline as deposits were worked out and as miners moved westward in response to the news of the discoveries in California in 1848. Appalachian production virtually ceased with the Civil War while production from California and adjacent states remained at several millions of ounces per year. As the California Gold Rush waned, new discoveries brought the Rocky Mountain states, South Dakota, and Alaska into prominence. Local, state and total production responded to time of discovery, extent of placers, labor availability, technology, government mandates and, of course, the price of gold. By 1900, the major gold rushes had occurred and most of the major producing districts were defined; however, the fixed price of gold (since 1837) provided a decreasingly attractive incentive for more exploration and exploitation. The rise in the price of gold, during the Depression provided a powerful incentive to increase gold production, but one that was cut short by War Production Board Order L-208 which closed the gold mines in 1942. In the post-war period, the fixed price, combined with the prohibition of American gold ownership, again proved to be a disincentive and gold production dropped. The era of free gold price that began in 1968, followed by the permission for Americans to again own gold, brought new interest in gold with prices rising briefly in 1980 to US$850 per ounce and remaining above US$350 per ounce through 1995. This higher price, combined with the technology for bulk mining and processing of low grade ores, provided incentive for new exploration and exploitation. Consequently, gold production soared above 10 million ounces per year in the early 1990's with 65% coming from Nevada. There has been a general decrease in the grade of gold ores since the early 1900's and significant changes in the methods of recovery. Despite the decreasing grade, the reserves of recoverable gold have more than doubled since the early 1970's.  相似文献   
104.
试论地球内部流体与地质作用——现代地质科学研究思考   总被引:11,自引:0,他引:11  
把以地球固体部分作为主要研究对象所建立起来的地质科学称为传统地质科学,它只在该学科研究的起点——沉积地质学和学科研究的最终目的——成矿地质学两个领域不自觉地将地球内部流体放到了重要地位,而在其间的绝大多数研究则忽略了对地球内部流体的讨论,在其原有的知识体系范围内已找不到关于地球内部物质和能量转移、转换等方面所存在的大量问题的解决途径和完整答案。现代地质科学的发展已经开始将地球内部流体作为主要研究对象,并将其贯穿到了所有地质学研究的领域当中。其基本出发点应是:地球内部流体广泛存在,并永不停息地运动着,它与固体地球部分同样重要,是现代地质科学研究的主要对象。它不仅在各种地质作用中起着极其重要的作用, 而且, 它基本上可以认为是一切地质作用的最初根源, 也就是说, 流体作用贯穿于一切地质作用( 包括构造活动、岩浆作用、变质作用、沉积作用、成矿作用、地质自然灾害等) 过程的始终。地球内部一切地质作用又通过地球内部流体有机地统一在一起。可将地球内部流体按其与特定地质作用的关系划分为具包含循环性质的初始流体、过程流体和终结流体三类。针对目前的研究大量地集中在过程流体和终结流体方面的现状, 在体现现代地质科学和传统地质科学本质区别的地质作用初始流体方面进行了系统整理和论述, 并提出了可能成为现代地质科学基础性学科的(地球内部) 流体统一地质学。  相似文献   
105.
Sedimentological parameters and stable O- and C-isotopic composition of marl and ostracode calcite selected from a 17.7-m-long core from the 8-m-deep center of Pickerel Lake, northeastern South Dakota, provide one of the longest (ca. 12ky) paleoenvironmental records from the northern Great Plains. The late Glacial to early Holocene climate in the northern Great Plains was characterized by changes from cold and wet to cold and dry, and back to cold and wet conditions. These climatic changes were controlled by fluctuations in the positions of the Laurentide ice sheet and the extent of glacial Lake Agassiz. We speculate that the cold and dry phase may correspond to the Younger Dryas event. A salinity maximum was reached between 10.3 and 9.5 ka, after which Pickerel Lake shifted from a system controlled by atmospheric changes to a system controlled by groundwater seepage that might have been initiated by the final withdrawal of Glacial Lake Agassiz. A prairie lake was established at approximately 8.7 ka, and lasted until about 2.2 ka. During this mid-Holocene prairie period, drier conditions than today prevailed, interrupted by periods of increased moisture at about 8, 4, and 2.2 ka. Prairie conditions were more likely dry and cool rather than dry and warm. The last 2.2 ka are characterized by higher climatic variability with 400-yr aridity cycles including the Medieval Warm Period and the Little Ice Age.Although the signal of changing atmospheric circulation is overprinted by fluctuations in the positions of the ice sheet and glacial Lake Agassiz during the late Glacial-Holocene transition, a combination of strong zonal circulation and strong monsoons induced by the presence of the ice sheet and high insolation may have provided mechanisms for increased precipitation. Zonal flow introducing dry Pacific air became more important during the prairie period but seems to have been interrupted by short periods of stronger meridional circulation with intrusions of moist air from the Gulf of Mexico. More frequent switching between periods of zonal and meridional circulation seem to be responsible for increased climatic variability during the last 2.2 ka.  相似文献   
106.
This county-level study examines the locational concentrations of membership in a sample of national environmental organizations. Maps of location quotients indicate distinct regions of high and low membership concentrations, with membership most concentrated in the Northeast, West, and Rocky Mountain states. The results may be helpful in identifying general patterns of environmental concern in different U.S. regions.  相似文献   
107.
钒的生物效应及其环境地球化学行为   总被引:8,自引:0,他引:8  
微量元素与人体健康间的关系,近年来日益受到重视。钒是动物和人体所必需的微量元素。适量有益。过量则有毒。钒的毒性大小取决于钒的总量、钒的赋存价态和赋存形态。本文综述了近年来国内外科研工作者在钒的生物效应、环境中钒的来源及环境介质中钒的赋存状况等方面所做的工作。  相似文献   
108.
Michael Flitner 《Geoforum》2003,34(2):175-185
The article deals with the role of genetics in the state-led agricultural modernization efforts that took place in different industrialized countries during the course of the 1920s and 1930s. A comparison between Germany, the Soviet Union and the United States shows substantial similarities in their attempts to increase the productivity of agriculture on different geographical scales. Following advances in scientific knowledge about the geography of cultivated plants, these countries sent out numerous expeditions to collect plant breeding material from all over the world. At the same time, states tightened their grip on farmers’ and breeders’ activities inside the country by establishing legal rules for the use of plant varieties and seed. But this was only one side of a larger “genetic modernization” project. In all three countries, concepts of agricultural modernization were substantially linked to social-darwinist thought which embraced programs of eugenics and “racial hygiene”. These links are outlined for each of the cases, highlighting the widely differing intermingling of scientific concepts and terminologies with political ideologies. It is then discussed what role geography and in particular geopolitical thinking of the time were to play in the development of “genetic modernization”, and more specifically, with regard to the nexus between agriculture and eugenics. While the discipline’s involvement in both fields remained comparably marginal in practical terms, clearly there were conceptual contributions toward the development of the broader field. Going back to Ratzel’s and Kjellén’s work, it is argued that geography had an important role in the establishment of a political field in which ideas of managing human reproduction were fused with concepts of economic development and environmental determinism.  相似文献   
109.
Geophysical and hydrochemical borehole-logging techniques were integrated to characterize hydraulic and hydrogeochemical properties of the Chalk aquifer at boreholes in Berkshire, UK. The down-hole measurements were made to locate fissures in the chalk, their spatial extent between boreholes, and to determine the groundwater chemical quality of the water-bearing layers. The geophysical borehole logging methods used were caliper, focused resistivity, induction resistivity, gamma ray, fluid temperature, fluid electrical conductivity, impeller and heat-pulse flowmeter, together with borehole wall optical-imaging. A multiparameter data transmitter was used to measure groundwater temperature, electrical conductivity, dissolved oxygen, pH, and redox potential of the borehole fluid down-hole. High permeability developed at the Chalk Rock by groundwater circulation provides the major flow horizon at the Banterwick Barn study site and represents a conduit system that serves as an effective local hydraulic connection between the boreholes. The Chalk Rock includes several lithified solution-ridden layers, hardgrounds, which imply a gap in sedimentation possibly representing an unconformity. Lower groundwater temperature, high dissolved-oxygen content, and flowmeter evidence of preferential groundwater flow in the Chalk Rock indicated rapid groundwater circulation along this horizon. By repeating the logging at different times of the year under changing hydraulic conditions, other water-inflow horizons within the Chalk aquifer were recognized. Electronic Publication  相似文献   
110.
Derek H Alderman 《Area》2003,35(2):163-173
Streets named for Martin Luther King, Jr are common yet controversial features in cities across the United States. This paper analyses the politics of naming these streets as a 'scaling of memory'– a socially contested process of determining the geographic extent to which the civil rights leader should be memorialized. Debates over the scaling of King's memory revolve around the size of the named street, the street's level of prominence within a hierarchy of roads, and the degree to which the street transcends the spatial confines of the black community. A street-naming struggle in Eatonton, Georgia (USA) exposes how the scaling of memory can become a point of division and contest within the black community as activists seek to fulfil different political goals. Analysing these intra-racial contests allows for a fuller appreciation of the historical consciousness and geographic agency of African Americans rather than seeing them as a single, monolithic group.  相似文献   
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