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201.
This article investigates whether and the extent to which “white flight” from Hispanic and Limited English Proficient (LEP) students has been occurring in California’s public schools and further, examines the level (school or district) on which “white flight” may operate. Using school-level administrative data from the California Department of Education from 1990 to 2000, we estimate exponential growth rate models of white enrollment with school-level fixed effects. The results shed light on the implications of immigration for school segregation in the United States. The analysis indicates that white enrollment declined in response to increases in the number of Spanish-speaking LEP and Hispanic students, and that “white flight” from LEP or Hispanic students occurred more at the district than the school level in the case of primary schools, and at the school level for secondary schools. In addition, schools with higher percentages of Spanish LEP students in the school than the district, and with higher percentages in the district relative to the county, experienced greater losses in white enrollments than other schools, thus suggesting that higher levels of segregation in the wider metropolitan area accelerate white flight.  相似文献   
202.
Genetic testing is traditionally preceded by counselling to discuss its advantages and disadvantages with individuals so they can make informed decisions. The new technique of whole genome or exome sequencing, which is currently only used in research settings, can identify many gene mutations, including substantial numbers of mutations with unknown pathological effect; it may, therefore, threaten this balanced approach if it is used in a clinical setting. We discuss the ethical challenges of several approaches to pre- and postnatal DNA testing, individual privacy versus the interests of families and of scientists, and the clinician's duty to re-contact if new information or options become available.  相似文献   
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一个多世纪以来,人们对城市变迁展开了系统性的研究,其中一个焦点是城市的中央商务区(CBDs)。过去几十年里有大量关于中央商务区衰落问题的文献,焦点集中在这种衰退为什么会发生,以及可以出台哪些刺激性政策措施来重振这些地区。本文主要讨论大城市中较为发达的地区,从地理上说就是南非北部的前工业重镇。就这些问题南非的学者也有为数不多但值得我们重视的文献,他们以年鉴形式记录了中央商务区的衰落及后续的重振措施。与国际上的经验类似,研究的焦点集中在南非的主要大城市地区,而二线城市则不在研究者们关注的范围之内。本文概述二线城市布隆方丹的中央商务区重振所面临的前景和阻碍的目的是,尽管在开普敦和约翰内斯堡等城市开展一般性的重振项目对抑制中央商务区的进一步衰退有显著成效,但对布隆方丹这样的二线城市来说,可能还需要一些其他措施。  相似文献   
206.
This study evaluates the effects of the implementation of resident-oriented care on the job characteristics (job autonomy, job demands and social support) of nursing caregivers in three Dutch nursing homes. In a quasi-experimental design, experimental and control groups in both general and psychogeriatric wards were followed for up to 22 months, using a pre-test and two post-tests by means of written questionnaires and semi-structured interviews. The results showed that the intervention appeared to be partly successful. Last post-test regression analyses revealed significant increases in a number of design characteristics of resident-oriented care. Significant increases were noticed on resident assignment, the two variables measuring the nursing process and, in the psychogeriatric experimental group, on resident-oriented tasks (p≤.01). The effects on job characteristics were limited. An indicative increase was shown in contextual job autonomy in the experimental group (p≤.05). The qualitative data derived from the interviews showed that there was still a partly task-oriented division of labour. Further, the delegation of co-ordination tasks to nursing caregivers had not yet been properly achieved. The study concludes with some theoretical and methodological reflections in the light of the findings.  相似文献   
207.
Abstract

Numerous tools have been developed that attempt to measure work-related stress and working conditions, but few practical instruments in the literature have been found to have a reliable psychometric factor structure. In the UK, the Health and Safety Executive (HSE) Management Standards (MS) Indicator Tool is increasingly used by organizations to monitor working conditions that can lead to stress. In Health and Safety Executive (2004), a factor analysis was conducted demonstrating the reliability of the scales. However, the authors acknowledged that direct reassessment of the same factor structure was impossible as the questionnaire was split into two separate modules for data collection. Furthermore, the tool is designed to enable comparisons between as well as within organizations to take place, yet reliability has only previously been tested at the individual level. The current study is the first to examine the factor structure of the HSE MS Indicator Tool using organizational-level data. Data collected from 39 UK organizations (N=26,382) was used to perform a first-order Confirmatory Factor Analysis (CFA) on the original 35-item seven-factor measurement scale. The results showed an acceptable fit to the data for the instrument. A second-order CFA was also performed to test if the Indicator Tool contains a higher order uni-dimensional measure of work-related stress. These findings also revealed an acceptable fit to the data, suggesting that it may be possible to derive a single measure of work-related stress. Normative data comprising tables of percentiles from the organizational data are provided to enable employers to compare their organizational averages against national benchmarks.  相似文献   
208.
ABSTRACT

This one-year follow-up study among 1,421 male nurses from seven European countries tested the validity of the Effort-Reward Imbalance (ERI) model in predicting prospective vital exhaustion and work-home interference. We hypothesised that effort and lack of reward would have both main and interactive effects on future outcomes. Results of structural equation modelling (SEM) showed that effort was positively related to exhaustion and work-home interference, both simultaneously and over time. Lack of reward predicted increased exhaustion at follow-up, but effort-reward imbalance did not influence the outcomes. Additionally, Time 1 exhaustion predicted increased work-home interference and exhaustion at follow-up. These results do not support the ERI model, which postulates a primacy of effort-reward imbalance over main effects. Instead, the findings are in line with dual path models of job stress and work-home interference. Multi-group SEM showed partial cross-cultural metric invariance for the ERI measure of effort, but the ERI measure of rewards showed no metric measurement invariance, indicating its meaning is qualitatively different across cultures. Nevertheless, the main conclusions were markedly similar for each national sub-sample. We discuss the theoretical and practical implications of our study.  相似文献   
209.
The Job Demands-Resources model predicts that job demands increase and job resources decrease emotional exhaustion in employees. In this study, we investigated one possible mechanism for this, in order to provide a deeper insight into the role of job resources in this energy-depletion process. We assumed that job resources (autonomy and task variety) reduce emotional exhaustion through the promotion of opportunities for personal growth and development, especially workplace learning. Moreover, we expected that job demands (workload, cognitive and emotional demands) would be positively related to work-related learning opportunities. Our research model was tested in a large and heterogeneous sample out of the Dutch working population (N = 4589), following a cross-validation procedure. Multi-group structural equation modelling revealed that autonomy and task variety promoted learning opportunities, which in turn partially mediated between these job resources and emotional exhaustion. With respect to job demands, our study showed mixed results: cognitive demands promoted learning opportunities, workload frustrated such opportunities, and emotional demands were not significantly related to learning opportunities. Our results contribute to a better understanding of the interplay between job demands, job resources and learning opportunities in the energy-depletion process, and support the need for the promotion of learning opportunities in the workplace.  相似文献   
210.

The feeder assignment and assembly sequence problem in printed circuit board (PCB) assembly with the twin objectives of minimizing magazine travel time and minimizing board travel time is presented in this study. The problem uses Dynamic Pick-and-Place (DPP) model where robot arm, board and magazine move together with different speeds based on relative coordinates between consecutive assembled points. The difficulty of the problem is that the feeder assignment depends on assembly sequence and vice versa. A new approach is proposed to improve the existing approaches. The trade-off between two strategies, assembly by area and assembly by component types, can give better results. The numerical experiments proved the efficiency of the new algorithm.  相似文献   
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