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91.
This article develops a simultaneous supply-and-demand model of the American steel industry for the years 1920–1972. The analysis takes into account the differences between published (book) and actual transactions prices. The model also provides for the oligopolistic nature of the steel market and the possibility that price may deviate from marginal cost. The demand results are in conformance with theory and earlier empirical work, but on the supply side some problems exist with the input price parameters. A reason for this situation may be that the steel industry is a large user of some inputs, making the relationship between steel output and these factor prices simultaneous.  相似文献   
92.
In this paper a neat construction is provided for three new families of group divisible designs that generalize some designs from Clatworthy's table of the only 11 designs with two associate classes that have block size four, three groups, and replication numbers at most 10. In each case (namely, λ1=4λ1=4 and λ2=5λ2=5, λ1=4λ1=4 and λ2=2λ2=2, and λ1=8λ1=8 and λ2=4λ2=4), we have proved that the necessary conditions found are also sufficient for the existence of such GDD's with block size four and three groups, with one possible exception.  相似文献   
93.
94.
The literature has shown that people who do not drink alcohol are at greater risk for death than light to moderate drinkers, yet the reasons for this remain largely unexplained. We examine whether variation in people’s reasons for nondrinking explains the increased mortality. Our data come from the 1988–2006 National Health Interview Survey Linked Mortality File (N = 41,076 individuals age 21 and above, of whom 10,421 died over the follow-up period). The results indicate that nondrinkers include several different groups that have unique mortality risks. Among abstainers and light drinkers the risk of mortality is the same as light drinkers for a subgroup who report that they do not drink because of their family upbringing, and moral/religious reasons. In contrast, the risk of mortality is higher than light drinkers for former drinkers who cite health problems or who report problematic drinking behaviors. Our findings address a notable gap in the literature and may inform social policies to reduce or prevent alcohol abuse, increase health, and lengthen life.  相似文献   
95.

Users of multistate life tables and projections have recognized that the Markovian assumptions underlying such models are unduly restrictive and should be relaxed whenever data permit. Efforts to include the influences of previous occupancies have included the incorporation of place‐of‐birth dependence. This paper addresses the stable growth properties of such generalized multistate models. It shows how place‐of‐birth‐specific stable growth measures can be calculated without projection simply by solving the characteristic equation. An example using Canadian data illustrates the argument.  相似文献   
96.

This paper outlines the discrete‐time and continuous‐time formulations of the stable population model with immigration, showing their commonality. It then illustrates how the model can be extended to include multiple interacting populations, and goes on to consider a multistate version of reproductive value that further illuminates the evolutionary dynamics of an “open”; model of multistate population growth and redistribution. Attention is restricted to results arising from a fertility regime that is below replacement level.  相似文献   
97.
This paper considers Charles Tilly as an important but underappreciated theorist of nationalism. Tilly’s theory of nationalism emerged from the “bellicist” strand of his earlier work on state-formation and later incorporated a concern with performance, stories, and cultural modeling. Yet despite the turn to culture in Tilly’s later work, his theory of nationalism remained state-centered, materialist, and instrumentalist—a source of both its power and its limitations.  相似文献   
98.
Age-related declines in capabilities may compromise older adults’ ability to maintain their homes, threatening successful aging in place. Structured interviews were conducted with 44 independently living older adults (mean age = 76.1, standard deviation = 4.7) to discuss difficult home maintenance tasks and how they managed those tasks. Solutions to managing difficulties were categorized as person-related or environment-related. The majority (85%) of responses were person-related solutions. An understanding of the specific challenges that older adults face in maintaining their homes can guide redesign efforts and interventions to effectively support older adults’ desire to age in place.  相似文献   
99.
The relationship between family structure and marijuana use throughout adolescence was assessed among 1,069 African Americans from the NLSY. A model was also tested suggesting that the effects of family structure on marijuana use would be mediated by poverty, neighborhood quality, and adolescents' self‐control. As most prior studies have found, family structure was not related to female adolescents' marijuana use. For young men, being raised with both biological parents was associated with less marijuana use throughout adolescence compared to those whose mothers never married, divorced early and never remarried, or divorced and remarried. Some support for the model was also found. We concluded that being raised without the presence of a biological father is a risk factor for marijuana use among young men, but African American young women from single‐parent households have unique resources that protect them from marijuana use. Understanding those resources may offer insight into prevention programs for other youth.  相似文献   
100.
Challenges to Aging in Place: Understanding Home Maintenance Difficulties   总被引:1,自引:0,他引:1  
Age-related declines in capabilities may compromise older adults' ability to maintain their homes thus threatening successful aging in place. Structured interviews were conducted with forty-four independently living older adults (M(age) = 76.1, SD = 4.7) to discuss difficult home maintenance tasks and how they managed those tasks. Solutions to managing difficulties were categorized as person-related or environment-related. The majority (85%) of responses were person-related solutions. An understanding of the specific challenges that older adults face in maintaining their homes can guide redesign efforts and interventions to effectively support older adults' desire to age in place.  相似文献   
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