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331.
The purpose of this paper is to explain why low-wage workers with identical qualifications to higher-wage workers are more exposed to unemployment. Each worker is considered to belong to a social group (defined according to his/her gender, age, and nationality). We assume that workers experience both productive interdependencies and social interactions within the firm. Also inter- and intra-group interactions determine worker productivity, and frictions on the labor market limit the hiring of the most productive workers. Consequently, externalities acting both within the firm and in the labor market can lead to a higher rate of unemployment for low-wage workers. 相似文献
332.
Esben Budtz‐Jrgensen David Bellinger Bruce Lanphear Philippe Grandjean 《Risk analysis》2013,33(3):450-461
Lead is a recognized neurotoxicant, but estimating effects at the lowest measurable levels is difficult. An international pooled analysis of data from seven cohort studies reported an inverse and supra‐linear relationship between blood lead concentrations and IQ scores in children. The lack of a clear threshold presents a challenge to the identification of an acceptable level of exposure. The benchmark dose (BMD) is defined as the dose that leads to a specific known loss. As an alternative to elusive thresholds, the BMD is being used increasingly by regulatory authorities. Using the pooled data, this article presents BMD results and applies different statistical techniques in the analysis of multistudy data. The calculations showed only a limited variation between studies in the steepness of the dose‐response functions. BMD results were quite robust to modeling assumptions with the best fitting models yielding lower confidence limits (BMDLs) of about 0.1–1.0 μ g/dL for the dose leading to a loss of one IQ point. We conclude that current allowable blood lead concentrations need to be lowered and further prevention efforts are needed to protect children from lead toxicity. 相似文献
333.
In order to engage mothers who are victims of domestic abuse, the child welfare worker needs to be challenged to develop an intentional practice response that includes knowledge and skill concerning the complexities of domestic violence, as well as the process of change. Developing a supportive relationship, understanding the stages of change (SOC) and engaging mothers as leaders in the change process are essential to successful child protection outcomes. Within the context of the SOC model, this practice‐based paper focuses on the importance of engaging mothers who are victims of domestic violence in conversations about their own unique dilemmas, challenges and barriers regarding change. Through the inclusion of engagement strategies such as signs of safety, active listening and cost/benefit analysis, in concert with the SOC theory, the child welfare worker would be equipped with an approach to successfully assist mothers through their change journey, ultimately keeping children safe. 相似文献
334.
An Empirical Approach to Sufficient Similarity: Combining Exposure Data and Mixtures Toxicology Data
Scott Marshall Chris Gennings Linda K. Teuschler LeAnna G. Stork Rogelio Tornero‐Velez Kevin M. Crofton Glenn E. Rice 《Risk analysis》2013,33(9):1582-1595
When assessing risks posed by environmental chemical mixtures, whole mixture approaches are preferred to component approaches. When toxicological data on whole mixtures as they occur in the environment are not available, Environmental Protection Agency guidance states that toxicity data from a mixture considered “sufficiently similar” to the environmental mixture can serve as a surrogate. We propose a novel method to examine whether mixtures are sufficiently similar, when exposure data and mixture toxicity study data from at least one representative mixture are available. We define sufficient similarity using equivalence testing methodology comparing the distance between benchmark dose estimates for mixtures in both data‐rich and data‐poor cases. We construct a “similar mixtures risk indicator”(SMRI) (analogous to the hazard index) on sufficiently similar mixtures linking exposure data with mixtures toxicology data. The methods are illustrated using pyrethroid mixtures occurrence data collected in child care centers (CCC) and dose‐response data examining acute neurobehavioral effects of pyrethroid mixtures in rats. Our method shows that the mixtures from 90% of the CCCs were sufficiently similar to the dose‐response study mixture. Using exposure estimates for a hypothetical child, the 95th percentile of the (weighted) SMRI for these sufficiently similar mixtures was 0.20 (i.e., where SMRI <1, less concern; >1, more concern). 相似文献
335.
Ana P. Martinez‐Donate Melbourne F. Hovell Jennifer Zellner Carol L. Sipan Elaine J. Blumberg Claudia Carrizosa 《Journal of sex research》2013,50(3):267-278
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 I, 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 psy‐chosocial correlates of HFV transmission. We discuss implications of these results. 相似文献
336.
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338.
Wendy D. Roth Marc‐David L. Seidel Dennis Ma Eiston Lo 《The International migration review》2012,46(2):310-361
The economic benefits to immigrants of taking jobs in ethnic workplaces, relative to the open economy, are heavily debated. We examine longitudinally differences across immigrant categories in how the choice of ethnic or non‐ethnic workplace influences the ethnic composition of social networks and how these factors impact immigrants’ economic success. Using the Longitudinal Survey of Immigrants to Canada, with data 6 months, 2 years, and 4 years after arrival, we find support for both sides of the ethnic economy debate when it is qualified by immigrant category. While economic immigrants benefit from non‐ethnic workplaces, family immigrants face economic penalties in the open economy and do better in ethnic workplaces. We argue that policies sorting immigrants into visa categories do much of the work of leading them into segmented paths of incorporation. 相似文献
339.
Hsiu‐Lan Shelley Tien Ying‐Fen Wang Ling‐Chun Liu 《The Career development quarterly》2009,57(3):274-288
The purpose of this study was to examine the role of career barriers in social cognitive career theory (R. W. Lent, S. D. Brown, & G. Hackett, 1994). The participants were 584 high school students in Taiwan, Republic of China. The gender differences in perceived career barriers and career self‐efficacy were significant. Results of hierarchical regression analyses indicated that some of the perceived career barriers were significant in predicting individuals' career choice behavior after controlling for career self‐efficacy in certain career types. 相似文献
340.
Learning to walk is a dynamic process requiring the fine coordination, assembly, and balancing of many body segments at once. For the young walker, coordinating all these behavioral levels may be quite daunting. In this study, we examine the whole‐body strategies to which infants resort to produce their first independent steps and progress over the first months of walking experience. Six infants were followed weekly from the onset of independent upright locomotion for 8 weeks, and then every other week until 4 months of walking experience. The walking kinematics from the infants' earliest steps were cluster‐analyzed and the infants were classified into 3 groups. Follow‐up comparisons with kinematics recordings were used to quantify the infants' strategies more precisely and track how these early forms of walking evolved over time. Results revealed that in the first weeks of independent walking, 3 infants used a stepping strategy, 1 used a twisting strategy, and 2 used a falling strategy to move their body forward and perform their first unsupported steps. As the infants gained walking experience, their walking patterns became more similar. These findings indicate that infants discover different solutions to use their body and control their balance when beginning to walk. With time, infants adopt a more efficient solution that incorporates and integrates elements of the different strategies. 相似文献