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861.
Expanding Boundaries of Whiteness? A Look at the Marital Patterns of Part‐White Multiracial Groups 下载免费PDF全文
Michael H. Miyawaki 《Sociological Forum》2015,30(4):995-1016
Using a boundary perspective (Alba and Nee 2003 ), I examine the marital behavior of three self‐identified multiracial groups: black/whites, American Indian/whites, Asian/whites. With a focus on marriage with whites, I assess whether the boundaries of whiteness are expanding to include these part‐white multiracial groups. Marrying whites at a large scale may signify that part‐white multiracial Americans are in the process of being accepted as “white.” At the same time, due to differences in the racial identity experiences of multiracial groups, marital patterns may differ by racial combination. Based on analysis of 2008–2012 American Community Survey data, I find that the majority of all three groups are married to whites, suggesting that most members in these groups are on the path to whiteness. On the other hand, multinomial logistic regression analysis demonstrates that American Indian/whites and Asian/whites are more likely than black/whites to have a white spouse, relative to spouses of another race/ethnicity. Moreover, separate regression analyses by multiracial group reveal gender differences in their likelihood of marrying whites for black/whites and Asian/whites. These results indicate racial stratification in the marriage market among part‐white multiracial Americans, with further stratification by gender for some groups. 相似文献
862.
Diesel Engine Exhaust and Lung Cancer Mortality: Time‐Related Factors in Exposure and Risk 下载免费PDF全文
Suresh H. Moolgavkar Ellen T. Chang Georg Luebeck Edmund C. Lau Heather N. Watson Kenny S. Crump Paolo Boffetta Roger McClellan 《Risk analysis》2015,35(4):663-675
To develop a quantitative exposure‐response relationship between concentrations and durations of inhaled diesel engine exhaust (DEE) and increases in lung cancer risks, we examined the role of temporal factors in modifying the estimated effects of exposure to DEE on lung cancer mortality and characterized risk by mine type in the Diesel Exhaust in Miners Study (DEMS) cohort, which followed 12,315 workers through December 1997. We analyzed the data using parametric functions based on concepts of multistage carcinogenesis to directly estimate the hazard functions associated with estimated exposure to a surrogate marker of DEE, respirable elemental carbon (REC). The REC‐associated risk of lung cancer mortality in DEMS is driven by increased risk in only one of four mine types (limestone), with statistically significant heterogeneity by mine type and no significant exposure‐response relationship after removal of the limestone mine workers. Temporal factors, such as duration of exposure, play an important role in determining the risk of lung cancer mortality following exposure to REC, and the relative risk declines after exposure to REC stops. There is evidence of effect modification of risk by attained age. The modifying impact of temporal factors and effect modification by age should be addressed in any quantitative risk assessment (QRA) of DEE. Until there is a better understanding of why the risk appears to be confined to a single mine type, data from DEMS cannot reliably be used for QRA. 相似文献
863.
Reanalysis of the DEMS Nested Case‐Control Study of Lung Cancer and Diesel Exhaust: Suitability for Quantitative Risk Assessment 下载免费PDF全文
Kenny S. Crump Cynthia Van Landingham Suresh H. Moolgavkar Roger McClellan 《Risk analysis》2015,35(4):676-700
The International Agency for Research on Cancer (IARC) in 2012 upgraded its hazard characterization of diesel engine exhaust (DEE) to “carcinogenic to humans.” The Diesel Exhaust in Miners Study (DEMS) cohort and nested case‐control studies of lung cancer mortality in eight U.S. nonmetal mines were influential in IARC's determination. We conducted a reanalysis of the DEMS case‐control data to evaluate its suitability for quantitative risk assessment (QRA). Our reanalysis used conditional logistic regression and adjusted for cigarette smoking in a manner similar to the original DEMS analysis. However, we included additional estimates of DEE exposure and adjustment for radon exposure. In addition to applying three DEE exposure estimates developed by DEMS, we applied six alternative estimates. Without adjusting for radon, our results were similar to those in the original DEMS analysis: all but one of the nine DEE exposure estimates showed evidence of an association between DEE exposure and lung cancer mortality, with trend slopes differing only by about a factor of two. When exposure to radon was adjusted, the evidence for a DEE effect was greatly diminished, but was still present in some analyses that utilized the three original DEMS DEE exposure estimates. A DEE effect was not observed when the six alternative DEE exposure estimates were utilized and radon was adjusted. No consistent evidence of a DEE effect was found among miners who worked only underground. This article highlights some issues that should be addressed in any use of the DEMS data in developing a QRA for DEE. 相似文献
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Erzsébet Bukodi John H. Goldthorpe Lorraine Waller Jouni Kuha 《The British journal of sociology》2015,66(1):93-117
Social mobility is now a matter of greater political concern in Britain than at any time previously. However, the data available for the determination of mobility trends are less adequate today than two or three decades ago. It is widely believed in political and in media circles that social mobility is in decline. But the evidence so far available from sociological research, focused on intergenerational class mobility, is not supportive of this view. We present results based on a newly‐constructed dataset covering four birth cohorts that provides improved data for the study of trends in class mobility and that also allows analyses to move from the twentieth into the twenty‐first century. These results confirm that there has been no decline in mobility, whether considered in absolute or relative terms. In the case of women, there is in fact evidence of mobility increasing. However, the better quality and extended range of our data enable us to identify other ‘mobility problems’ than the supposed decline. Among the members of successive cohorts, the experience of absolute upward mobility is becoming less common and that of absolute downward mobility more common; and class‐linked inequalities in relative chances of mobility and immobility appear wider than previously thought. 相似文献
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Prior to 2007, two systems of bus driver compensation coexisted in Santiago, Chile: one paid drivers per passenger transported, while the other paid a fixed wage. Per‐passenger drivers engaged in “The War for the Fare,” altering their driving patterns to compete for passengers. Examining these systems on similar routes in Santiago, we observed two key findings. Compared with the fixed‐wage system, the per‐passenger system leads to (1) 13% shorter passenger wait times, via reduced bunching of buses and (2) 67% more accidents per kilometer driven, via more aggressive driving. We discuss implications for the design of incentives in public transit. (JEL L92, M52, R41) 相似文献
869.
To adjust or not to adjust for baseline when analyzing repeated binary responses? The case of complete data when treatment comparison at study end is of interest 下载免费PDF全文
Honghua Jiang Pandurang M. Kulkarni Craig H. Mallinckrodt Linda Shurzinske Geert Molenberghs Ilya Lipkovich 《Pharmaceutical statistics》2015,14(3):262-271
The benefits of adjusting for baseline covariates are not as straightforward with repeated binary responses as with continuous response variables. Therefore, in this study, we compared different methods for analyzing repeated binary data through simulations when the outcome at the study endpoint is of interest. Methods compared included chi‐square, Fisher's exact test, covariate adjusted/unadjusted logistic regression (Adj.logit/Unadj.logit), covariate adjusted/unadjusted generalized estimating equations (Adj.GEE/Unadj.GEE), covariate adjusted/unadjusted generalized linear mixed model (Adj.GLMM/Unadj.GLMM). All these methods preserved the type I error close to the nominal level. Covariate adjusted methods improved power compared with the unadjusted methods because of the increased treatment effect estimates, especially when the correlation between the baseline and outcome was strong, even though there was an apparent increase in standard errors. Results of the Chi‐squared test were identical to those for the unadjusted logistic regression. Fisher's exact test was the most conservative test regarding the type I error rate and also with the lowest power. Without missing data, there was no gain in using a repeated measures approach over a simple logistic regression at the final time point. Analysis of results from five phase III diabetes trials of the same compound was consistent with the simulation findings. Therefore, covariate adjusted analysis is recommended for repeated binary data when the study endpoint is of interest. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
870.