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11.
This article examines linkages between recent domestic out-migration from immigrant gateway metropolitan areas and nonmetropolitan migration gains, based on data of the 1990 census, 1996 Current Population Survey, and population estimates for the 1990–1996 period from the Bureau of Census. Our analysis of these data suggests that there is a mirror image of migration patterns between high immigration metropolitan area losses and nonmetropolitan area gains. This is especially evident in the West with the relationship between Los Angeles and San Francisco areas' losses on the one hand, and the region's nonmetropolitan gains on the other. While pre-elderly and elderly retirees have contributed to these nonmetropolitan gains, much of it is attributable to the destination choices of suburban-like populations—Whites with children, not college educated, and with lower incomes—that have been leaving high immigration metropolitan areas. This new, more dispersed form of “White flight” holds the potential for reinvigorating smaller, nonmetropolitan communities, but creating, as well, new demographic divisions across space. 相似文献
12.
A new structural system for earthquake resistant steel structures is investigated in this paper. This new framing system, called the knee-brace-frame (KBF), is a braced frame with diagonal braces connected to ductile knee members. The diagonal braces provide the lateral stiffness, whereas the knee anchors yield in flexure to dissipate energy during severe seismic excitation. To assess the inelastic characteristics of the KBF, a large scale model of a KBF was tested using the pseudodynamic test procedure. The experimental results are compared with analytical results obtained from a DRAIN-2D model. It is found that, with an appropriate design of knee anchors, the KBF can be made to be ductile to dissipate energy during severe seismic excitation. 相似文献