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81.
To inform local and regional decisions about protecting short-term and long-term quality of life, the Consortium for Atlantic Regional Assessment (CARA) provides data and tools (for the northeastern United States) that can help decision makers understand how outcomes of their decisions could be affected by potential changes in both climate and land use. On an interactive, user-friendly website, CARA has amassed data on climate (historical records and future projections for seven global climate models), land cover, and socioeconomic and environmental variables, along with tools to help decision makers tailor the data for their own decision types and locations. CARA Advisory Council stakeholders help identify what information and tools stakeholders would find most useful and how to present these; they also provide in-depth feedback for subregion case studies. General lessons include: (1) decision makers want detailed local projections for periods short enough to account for extreme events, in contrast to the broader spatial and temporal observations and projections that are available or consistent at a regional level; (2) stakeholders will not use such a website unless it is visually appealing and easy to find the information they want; (3) some stakeholders need background while others want to go immediately to data, and some want maps while others want text or tables. This article also compares what has been learned across case studies of Cape May County, New Jersey, Cape Cod, Massachusetts, and Hampton Roads, Virginia, relating specifically to sea-level rise. Lessons include: (1) groups can be affected differently by physical dangers compared with economic dangers; (2) decisions will differ according to decision makers' preferences about waiting and risk tolerance; (3) future scenarios and maps can help assess the impacts of dangers to emergency evacuation routes, homes, and infrastructure, and the natural environment; (4) residents' and decision makers' perceptions are affected by information about potential local impacts from global climate change.  相似文献   
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This report summarizes the proceedings of a conference on quantitative methods for assessing the risks of developmental toxicants. The conference was planned by a subcommittee of the National Research Council's Committee on Risk Assessment Methodology 4 in conjunction with staff from several federal agencies, including the U.S. Environmental Protection Agency, U.S. Food and Drug Administration, U.S. Consumer Products Safety Commission, and Health and Welfare Canada. Issues discussed at the workshop included computerized techniques for hazard identification, use of human and animal data for defining risks in a clinical setting, relationships between end points in developmental toxicity testing, reference dose calculations for developmental toxicology, analysis of quantitative dose-response data, mechanisms of developmental toxicity, physiologically based pharmacokinetic models, and structure-activity relationships. Although a formal consensus was not sought, many participants favored the evolution of quantitative techniques for developmental toxicology risk assessment, including the replacement of lowest observed adverse effect levels (LOAELs) and no observed adverse effect levels (NOAELs) with the benchmark dose methodology.  相似文献   
85.
The skin is a route of exposure that needs to be considered when conducting a risk assessment. It is necessary to identify the potential for dermal penetration by a chemical as well as to determine the overall importance of the dermal route of exposure as compared with inhalation or oral routes of exposure. The physical state of the chemical, vapor or liquid, the concentration, neat or dilute, and the vehicle, lipid or aqueous, is also important. Dermal risk is related to the product of the amounts of penetration and toxicity. Toxicity involves local effects on the skin itself and the potential for systemic effects. Dermal penetration is described in large part by the permeability constant. When permeability constants are not known, partition coefficients can be used to estimate a chemical's potential to permeate the skin. With these concepts in mind, a tiered approach is proposed for dermal risk assessment. A key first step is the determination of a skin-to-air or skin-to-medium partition coefficient to estimate a potential for dermal absorption. Building a physiologically-based pharmacokinetic (PBPK) model is another step in the tiered approach and is useful prior to classical in vivo toxicity tests. A PBPK model can be used to determine a permeability constant for a chemical as well as to show the distribution of the chemical systemically. A detailed understanding of species differences in the structure and function of the skin and how they relate to differences in penetration rates is necessary in order to extrapolate animal data from PBPK models to the human. A study is in progress to examine anatomical differences for four species.  相似文献   
86.
Marriage and fertility in the United States have become less firmly entwined as more women bear children without marrying and more couples with children divorce. Today a sizeable number of children are expected to spend a portion of their childhood in one-parent households. Despite the trends in illegitimacy and divorce, the actual effect of out-of-wedlock childbearing on the living arrangements of children has not been fully explicated. Using the National Survey of Family Growth Cycle III, this paper estimates the probability that children aged 0–13 in 1982 are living in two-parent households, controlling for their mothers' marital statuses at their births. We find that marital status at birth is an important predictor of household structure at later ages for both white and black populations; however, the childhood environment is actually quite elastic as women marry, divorce, remarry, and redivorce.  相似文献   
87.
RURAL POVERTY, URBAN POVERTY, AND PSYCHOLOGICAL WELL-BEING   总被引:1,自引:0,他引:1  
Data from the National Survey of Families and Households are used to compare the psychological well-being of the rural and urban poor. Overall, the urban poor are higher in perceived health than the rural poor, although no differences are apparent in happiness or depression. Significant interactions are present between rural/urban poverty and sex, race, and family status. The psychological well-being of poor African Americans is higher in rural than urban areas, whereas the well-being of poor whites is higher in urban than rural areas. This trend is especially pronounced for depression among males. In addition, single men without children have especially high depression scores in rural areas, whereas married women without children have especially low depression scores in urban areas. The results are interpreted in terms of the environmental quality of inner-city neighborhoods and attitudes toward poverty in urban and rural communities.  相似文献   
88.
The mean density of bacteria in a water body is commonly monitored using quantal assay. This paper describes the use of local scoring in estimating the spatial distribution of mean density from quantal assay results at a set of point locations. An application to estimating the mean density of fecal conform bacteria in a coastal pond is presented. Model diagnostics based on a parametric bootstrap are also presented.  相似文献   
89.
Are the decisions of American policymakers informed by generaltrends in the public’s ideology or by the public’spolicy-specific preferences? In this article we discuss twoexplanations for the types of public opinion information thatpoliticians collect and use. Using a unique data set of privatepolls from the White House of Richard Nixon, we find that whenopinion data on specific policies were available, the presidentrelied on them and not on general ideology data. On less importantissues, however, we find that the president often chose notto collect policy-specific data and instead relied on generalideology data. The differential collection and use of informationby policymakers reflect varying strategic calculations. Theyalso have profound implications for representative democracyand the demands placed on citizens and governors.  相似文献   
90.
In this article we posit that racial discrimination is not uniform across the U.S. labor market. While it is likely that patterns of racial discrimination occur in some types of jobs more than others, little empirical research has examined the effect of race across segmented labor markets. Incorporating two decades of comparable General Social Survey data, this article revisits William J. Wilson's hypothesis that the significance of race in determining labor market outcomes is declining. We examine the effect of race within two dissimilar labor segments over time, dividing the labor market into technique‐versus social‐skills‐oriented segments. Using this theoretically useful dichotomy, we examine if the net effect of race (African American and white men) on occupational prestige has declined from the 1970s to the 1990s. Our multivariate analysis shows that the net effect of race is different in each labor market. This suggests that racial discrimination against African Americans is not uniform across the entire labor market, but instead is differentiately manifested within various labor market segments. Overall, our findings partially support Wilson's thesis indicating that while the effect of race is no longer a significant indicator of occupational prestige by the 1990s in a technique‐oriented job segment, it remains a significant predictive variable within a social‐skills‐oriented job segment, even when controlling for a range of social class and structural variables.  相似文献   
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