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On-going human population growth and changing patterns of resource consumption are increasing global demand for ecosystem services, many of which are provided by soils. Some of these ecosystem services are linearly related to the surface area of pervious soil, whereas others show non-linear relationships, making ecosystem service optimization a complex task. As limited land availability creates conflicting demands among various types of land use, a central challenge is how to weigh these conflicting interests and how to achieve the best solutions possible from a perspective of sustainable societal development. These conflicting interests become most apparent in soils that are the most heavily used by humans for specific purposes: urban soils used for green spaces, housing, and other infrastructure and agricultural soils for producing food, fibres and biofuels. We argue that, despite their seemingly divergent uses of land, agricultural and urban soils share common features with regards to interactions between ecosystem services, and that the trade-offs associated with decision-making, while scale- and context-dependent, can be surprisingly similar between the two systems. We propose that the trade-offs within land use types and their soil-related ecosystems services are often disproportional, and quantifying these will enable ecologists and soil scientists to help policy makers optimizing management decisions when confronted with demands for multiple services under limited land availability.  相似文献   
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Whereas sociologists have long recognized that adolescence marks the start of the socioeconomic career, the importance of this period has been attributed to school performance, aspirations, and significant others' influence that support educational attainment to a greater or lesser degree. The underlying premise of this study is that adolescent work is an expression of instrumental action with consequences for socioeconomic attainment. Using data from the Youth Development Study, we find that part-time work during high school is linked with patterns of schooling and working that persist during the succeeding years and are more or less conducive to the receipt of a BA/BS degree. Moderate work coupled with school appears to especially facilitate the educational attainment of low promise youth.  相似文献   
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Past cohorts of teenagers who spent long hours in jobs were more likely to drop out of high school than those who worked moderate hours or did not work at all. This article examines the association between employment intensity and dropout among adolescents in the High School Longitudinal Study of 2009 who traversed high school during a time of decreased prevalence of both employment and dropout relative to earlier cohorts. Analyses reveal that a relatively small percentage of teenagers nowadays are characterized as either intensive workers or dropouts (around 11% each). Yet, despite declines in intensive employment and dropout, disadvantaged youth remain overrepresented in both groups, and intensive work is still a risk factor for poor grades and dropout.  相似文献   
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Spiegelman M 《Demography》1966,3(2):574-577
The plan calls for monographs on 16 specific topics and a review volume. The specific topics include a monograph on fertility, another on marriage and divorce, and one on social and economic factors in mortality, all of which are of obvious demographic interest. The core of the development of the monographs dealing with the disease topics, and accidents, homicide, and suicide, is a tabulation program involving specific and age-adjusted death rates based upon the deaths in the United States for the three year period 1959-61 and the 1960 census of population. The program called for a set of standard tabulations common to each monograph and also a set of special tabulations tailored to meet the particular needs for each topic as specified by its authors. This wealth of demographic detail regarding mortality in the United States during 1959-61 fills only one aspect of its health picture. To fill out the health picture, use is being made of the great volume of morbidity data out of the National Health Interview and Examination Surveys and a wide variety of other specialized surveys. In all of these, the findings are invariably described in terms of the demographic characteristics of age and sex, and frequently in terms of such social-economic variables as education, income, work status, and occupational class.A large part of the content of the monograph on social and economic factors in mortality will come out of available results of the 1960 census-death certificate matching study at the University of Chicago. One important feature of this monograph, not contained in the Chicago study, is a regression and correlation analysis of total mortality in 202 Standard Metropolitan Statistical Areas in relation to a large number of social, economic, and climatic factors. Among the features in the monograph on fertility are chapters on the medical and biological characteristics of births, fecundity and family planning, and an analysis of cohort fertility trends. The monograph on marriage and divorce will make use of the detailed tabulations from the 1960 census on marital status in relation to education, race, parentage, earnings and other classifications of individuals and of husband and wife in married couples. It will also contain a matching study of divorce records in certain states for a short period before the census of 1960 with the returns in the census. The project is supported by a grant from the United States Public Health Service (CH 00075; formerly RG 08262). Publication will be by the Harvard University Press.  相似文献   
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Using longitudinal data from the Youth Development Study (analytic sample N = 712), we investigate how age, adult role acquisition and attainments, family resources, parent-child relationship quality, school attendance, and life events influence support received from parents in young adulthood. Parental assistance was found to be less forthcoming for those who had made greater progress on the road to adulthood, signified by socioeconomic attainment and union formation. The quality of mother-child and father-child relationships affected parental support in different ways, positively for mothers, negatively for fathers. School enrollment, negative life events, and employment problems were associated with a greater likelihood of receiving support. The findings suggest that parents act as "scaffolding" and "safety nets" to aid their children's successful transition to adulthood.  相似文献   
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Food safety scares make headlines. Fish in particular causes worry: should we eat it for our health, or avoid it for the pollutants that it accumulates? David Mortimer explains how the Food Standards Agency decides how much fish it is safe for us to eat.  相似文献   
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The transition from school to work is a story that meshes the life histories of youth and the economic and social development of societies. Drawing on reports from diverse regions of the world, this article describes the range of adolescent experiences as they encompass the completion of school and the commencement of adult work. As the 21st century begins, major threats to the preparation of youth for adult work include deficiencies in schools, hazards of the informal work sector, a lack of clear connections between school and work, and the misuse or underutilization of technology. Yet this transition is also a story of optimism, as the significance of youth for economic and social development is increasingly appreciated at the national and international levels. Accordingly, this article considers the broad policy implications of the survey and then details the lines of action that address challenges to the preparation of youth for adult work. Although many regions of the world share common challenges, the integration of youth into the 21st century world of work will depend on how each country formulates a unique response that is sensitive to its demographic profile, social institutions, cultural heritage, and economic conditions.  相似文献   
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