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91.
Changes in gay and bisexual men’s connectedness to the gay community are related to the declining public visibility of HIV/AIDS and greater acceptance for homosexuality and bisexuality in mainstream society. Little work, however, has focused on perceived acceptance for subgroups within the gay community or broader society. Using interviews (n = 20) and a survey (n = 202) of gay and bisexual men in a mid-sized Canadian city, we find perceived hierarchies of acceptance for the various subgroups as well as an age effect wherein middle-aged men perceive the least acceptance for all groups. These differences are linked with the uneven impact of social, political, and institutional changes relevant to gay and bisexual men in Canada.  相似文献   
92.
Least squares regression estimates of causal effects are conditional-variance-weighted estimates of individual-level causal effects. In this paper, we extract from the literature on counterfactual causality a simple nine-step routine to determine whether or not the implicit weighting of regression has generated a misleading estimate of the average causal effect. The diagnostic routine is presented along with a detailed and original demonstration, using data from the 2002 and 2004 waves of the Education Longitudinal Study, for a contested but important causal effect in educational research: the effect of Catholic schooling, in comparison to public schooling, on the achievement of high school students in the United States.  相似文献   
93.
In clinical trials, investigations focus upon whether a treatment affects a measured outcome. Data often collected include pre- and post-treatment measurements on each patient and an analysis of the change in the outcome is typically performed to determine treatment efficacy. Absolute change and relative change are frequently selected as the outcome. In selecting from these two measures, the analyst makes implicit assumptions regarding the mean and variance-mean relationship of the data. Some have provided ad hoc guidelines for selecting between the two measures. We present a more rigorous means of investigating change using quasi-likelihoods. We show that both absolute change and relative change are special cases of the specified quasi-likelihood model. A cystic fibrosis example is provided.  相似文献   
94.
Successfully documenting the outcomes of assistive technology (AT) interventions in the workplace benefits people with disabilities, service providers and agencies. However, no work related system currently exists that comprehensively collects the data needed to analyze such outcomes. Part of the reason for this absence of an outcome system is that, while the concept is simple, the process is complex and depends on the acquisition of data that represent many outcomes related variables. This article describes the exploratory work of the NIDRR (National Institute on Disability and Rehabilitation Research) funded ATOMS Project (Assistive Technology Outcomes Measurement System) and its efforts to identify existing data that might be used as the basis for an outcomes measurement system. Sample records from four assistive technology service programs were acquired and evaluated for the data they housed. This study discovered that AT service programs fail to collect consistent or sufficient data for outcomes analysis. However, discussions with AT programs that provided services to State vocational rehabilitation agencies revealed an interesting potential. Assistive technology service data in combination with data collected by State vocational rehabilitation departments might coalesce the needed data. The Federal Rehabilitation Services Administration (RSA) 911 Report aggregates many variables of outcomes related information including employment status and the success of the vocational rehabilitation investment. This combined database could answer a range of assistive technology outcomes related questions of interest to service providers, people with disabilities, and vocational rehabilitation State agencies. This paper describes the data needed in an outcomes system, reviews the data that appear to be available today related to AT outcomes, and projects how data from two diverse programs might be used together to create a significant outcomes database.  相似文献   
95.
A number of prominent demographers have recently reiterated the argument that a lasting mortality decline is a key determinant of the fertility transition. Of the main hypothesized pathways linking fertility to mortality, the one least studied is the insurance hypothesis: the notion that, in high‐mortality contexts, people decide to have more children in order to anticipate possible future child deaths and lessen the risks of having too few surviving offspring. In‐depth interviews and focus groups from Zimbabwe and Senegal are used to examine this hypothesis and to extend it into a broader theory of reproductive decision making under uncertainty. Whereas insurance strategies are frequent in Zimbabwe and occur in urban Senegal, in the higher‐mortality settings—the rural Senegalese site and the recent past described by respondents in Zimbabwe and urban Senegal—deliberate fertility‐limitation strategies are rare. The data depict fundamental changes in attitudes, strategies, and behaviors concerning family size over time and, in Senegal, over space. Important reproductive goals and risks extend far beyond numbers of children and mortality. Parents seek to have healthy, successful children for many reasons including companionship, descendants, and old‐age support. Diverse investments in child quality (their education, health, etc.) and quantity (numbers of births) are the main means to attain these goals and, less recognized by demographers, are also important ways for parents to manage uncertainty in family‐building outcomes; the “classic” insurance mechanism is only one, often minor, aspect of the quantity option.  相似文献   
96.
97.
This study examined the cross‐racial comparability of maternal quality of assistance and supportive presence coded from a video protocol using data from the Infant Health and Development Program for low‐birth‐weight, premature 30‐month‐olds and their mothers. Evidence of equivalence of measures is necessary before comparisons can be made across groups. Multiple‐group mean and covariance structures analysis was used to demonstrate the invariance of the measures and make comparisons for Anglo American and African American treatment and comparison groups of dyads. Comparisons across groups indicated similar variances and correlation between child and maternal behavior. Differences were found between the mean scores, with Anglo American treatment families scoring the highest.  相似文献   
98.
The qualities people believe are important in selecting a marriage partner afford one domain for assessing human values. We examined the cultural evolution of these values over more than half a century. Building on existing data on mate preferences collected in 1939 (N= 628 ), 1956 (N= 120 ), 1967 (N= 566 ), and 1977 (N= 316 ), we collected data using the same instrument in 1984/1985 (N= 1,496 ) and in 1996 (N= 607 ) at geographically diverse locations. Several changes in values were documented across the 57‐year span. Both sexes increased the importance they attach to physical attractiveness in a mate. Both sexes, but especially men, increased the importance they attach to mates with good financial prospects. Domestic skills in a partner plummeted in importance for men. Mutual attraction and love climbed in importance for both sexes. The sexes converged in the ordering of the importance of different mate qualities, showing maximum similarity in 1996. Discussion speculates about causes of the cultural evolution of values.  相似文献   
99.
Combinations of drugs are increasingly being used for a wide variety of diseases and conditions. A pre-clinical study may allow the investigation of the response at a large number of dose combinations. In determining the response to a drug combination, interest may lie in seeking evidence of 'synergism', in which the joint action is greater than the actions of the individual drugs, or of 'antagonism', in which it is less. Two well-known response surface models representing no interaction are Loewe additivity and Bliss independence, and Loewe or Bliss synergism or antagonism is defined relative to these. We illustrate an approach to fitting these models for the case in which the marginal single drug dose-response relationships are represented by four-parameter logistic curves with common upper and lower limits, and where the response variable is normally distributed with a common variance about the dose-response curve. When the dose-response curves are not parallel, the relative potency of the two drugs varies according to the magnitude of the desired effect and the models for Loewe additivity and synergism/antagonism cannot be explicitly expressed. We present an iterative approach to fitting these models without the assumption of parallel dose-response curves. A goodness-of-fit test based on residuals is also described. Implementation using the SAS NLIN procedure is illustrated using data from a pre-clinical study.  相似文献   
100.
Evaluating the impact of poverty-reduction programs on fertility is complicated given that changes in incentives to have children take time to be incorporated into decision making and evaluation periods are usually quite brief. We explore the use of birth spacing as a short-run indicator of the impact of poverty-reduction programs on fertility. The data come from a Nicaraguan conditional cash transfer program that offers incentives for poor households to invest in children’s health, nutrition, and education. We estimate a stratified Cox proportional hazard model and find that the program decreased the hazard of a birth, indicating an increase in birth spacing.  相似文献   
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