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971.
972.
Public opinion surveys purport to express the public's opinion. The literature on survey techniques has, however, recognized various potential limitations to the validity of survey results. While improved survey methodology may reduce statistical bias and improve validity, it cannot avoid the implicit weighting of preferences. This normative aspect of surveying has often been unrecognized or disguised as a purely technical matter. Such things as sample selection, choice of survey instrument and the method of aggregating results will each contribute to a pattern of preference weights. Several common survey techniques are examined in this light. It is proposed that no single ‘correct’ method of preference aggragation exists. Increased public recognition of, and debate on this normative aspect of surveying is recommended.  相似文献   
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976.
Twenty-four-hour recall data from the Continuing Survey of Food Intake by Individuals (CSFII) are frequently used to estimate dietary exposure for risk assessment. Food frequency questionnaires are traditional instruments of epidemiological research; however, their application in dietary exposure and risk assessment has been limited. This article presents a probabilistic method of bridging the National Health and Nutrition Examination Survey (NHANES) food frequency and the CSFII data to estimate longitudinal (usual) intake, using a case study of seafood mercury exposures for two population subgroups (females 16 to 49 years and children 1 to 5 years). Two hundred forty-nine CSFII food codes were mapped into 28 NHANES fish/shellfish categories. FDA and state/local seafood mercury data were used. A uniform distribution with minimum and maximum blood-diet ratios of 0.66 to 1.07 was assumed. A probabilistic assessment was conducted to estimate distributions of individual 30-day average daily fish/shellfish intakes, methyl mercury exposure, and blood levels. The upper percentile estimates of fish and shellfish intakes based on the 30-day daily averages were lower than those based on two- and three-day daily averages. These results support previous findings that distributions of "usual" intakes based on a small number of consumption days provide overestimates in the upper percentiles. About 10% of the females (16 to 49 years) and children (1 to 5 years) may be exposed to mercury levels above the EPA's RfD. The predicted 75th and 90th percentile blood mercury levels for the females in the 16-to-49-year group were similar to those reported by NHANES. The predicted 90th percentile blood mercury levels for children in the 1-to-5-year subgroup was similar to NHANES and the 75th percentile estimates were slightly above the NHANES.  相似文献   
977.
In evaluating family preservation services, it is important not only to study the service outcomes and the family characteristics, but also what actually happens during the treatment. This requires a program model. This article describes how a program model works, prescribes how workers should carry it out, and describes how researchers should measure the program's characteristics. The authors use data from Families First in The Netherlands to test the model. Results show that the method of the program meets the specified characteristics. The results are important for treatment, policy, education, and evaluation research.  相似文献   
978.
This study describes depressive symptoms among caregivers following bereavement and connects these trajectories to earlier features of caregiving using life course and stress process theory. Data are from a six-wave longitudinal survey (five years) of spouses and adult children caring for someone with Alzheimer's Disease. The analytic subsample (N = 291) is defined by death of the care-recipient after the baseline interview. A latent class mixture model is used to identify distinctive clusters of depressive symptoms over time. Of the four trajectories identified, three represent stable symptom levels over time, with two-thirds being repeatedly symptomatic (medium symptom levels), compared to two smaller groups of repeatedly asymptomatic (effectively absent of symptoms) and repeatedly distressed (severe symptoms). In contrast, about one in five caregivers experiences improved emotional well-being over time, the temporarily distressed, who progress from severe to moderate symptom levels. Caregivers with few symptoms before bereavement tend to maintain these states afterwards, but emotionally distressed caregivers tend to become more distressed. Role overload before bereavement substantially increases the odds of following an unfavorable trajectory afterwards, whereas self-esteem and socioemotional support play protective roles. These results demonstrate that caregivers are not uniform in their emotional responses to bereavement, but follow several distinct trajectories. These trajectories are linked to their previous experiences as caregivers, in particular exposure to stressors and access to resources. These findings suggest that intervention during caregiving may facilitate adaptation following death of a loved one.  相似文献   
979.
Food insufficiency is a significant problem in the United States, and poor African American women with children are at especially high risk. An inadequate household food supply can potentially affect the well-being of household members, but it is difficult to distinguish the effects of food insufficiency from risk factors for poor health that are also common among the food insufficient, such as poverty. We examined food insufficiency and physical and mental health among African American and white women (n = 676) who were welfare recipients in 1997. Controlling for common risk factors, women who reported food insufficiency in both 1997 and 1998 were more likely to report fair or poor health at the later date. Food insufficiency in 1998 was significantly associated with meeting the diagnostic screening criteria for recent major depression. Food insufficiency at both times and in 1998 only was related to women's sense of mastery. These findings add to growing evidence that household food insufficiency is associated with poor physical and mental health.  相似文献   
980.
This research project examined the individual and combined effectiveness of an HIV prevention workshop and a free condom distribution program in four high schools in Tijuana, Mexico. Adolescents (N = 320) completed baseline measures on sexual practices and theoretical correlates and participated in a two-part study. In Study 1, students were randomly assigned to an HIV prevention workshop or a control condition, with a 3-month follow-up assessment. Results indicate three significant workshop benefits regarding HIV transmission by altering sexual initiation, access to condoms, and traditional beliefs regarding condoms. In Study 2, we set up a condom distribution program at two of the participating schools, and students completed a 6-month follow-up assessment. Results indicate that exposure to the workshop followed by access to the condom distribution program yielded two beneficial results for reducing HIV transmission: moderating sexual initiation and increasing condom acquisition. Access to the condom distribution program alone had no effects on behavioral and psychosocial correlates of HIV transmission. We discuss implications of these results.  相似文献   
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