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991.
This paper applies revealed preference theory to the nonparametric statistical analysis of consumer demand. Knowledge of expansion paths is shown to improve the power of nonparametric tests of revealed preference. The tightest bounds on indifference surfaces and welfare measures are derived using an algorithm for which revealed preference conditions are shown to guarantee convergence. Nonparametric Engel curves are used to estimate expansion paths and provide a stochastic structure within which to examine the consistency of household level data and revealed preference theory. An application is made to a long time series of repeated cross–sections from the Family Expenditure Survey for Britain. The consistency of these data with revealed preference theory is examined. For periods of consistency with revealed preference, tight bounds are placed on true cost of living indices.  相似文献   
992.
Achieving adequate levels of physical activity (PA) is important to maintain health and prevent chronic disease. The costs of inadequate physical activity to the NHS have been estimated at over a billion pounds annually. While socio-demographic characteristics such as age, sex and ethnicity have been reported to be associated with different levels of PA, there is evidence that people??s social environments may also be important in encouraging a physically active lifestyle. The objective of this paper is to describe associations between the social environment and physical activity among the poorer communities in an outer London Borough, when other socio-demographic factors are controlled for. A household survey was carried out in six poorer neighbourhoods in Redbridge in 2008 as part of a wider health needs assessment. The questionnaire included questions allowing estimation of levels of physical activity as well as extent of social environment [social network score (SNS) and social support score (SSS)]. A random sample of households was taken and a total of 799 completed responses from over 16 year old were obtained. The association between physical activity and the social environment controlling for socio-demographic characteristics was estimated using a logistic nested model. Higher SNS was significantly associated with younger age, Black ethnicity, higher education level, higher household income and higher levels of PA in bivariate analyses. Higher SSS was positively associated with Indian ethnicity, higher household income and area of residence. In multivariate analyses higher levels of PA were significantly associated with wider social networks and stronger social support, educational level and marital status. Despite its limitations, our findings confirm that the relationship between low physical activity and weak social networks and low social support, observed in general population studies, also occurs in deprived communities in London. The relationship merits further exploration given the limited evidence on the effectiveness of interventions to promote physical activity.  相似文献   
993.

News

Francine Blau receives IZA Prize in Labor Economics  相似文献   
994.
The Early Development Instrument (EDI; Janus and Offord in Canadian Journal of Behavioural Science 39:1–22, 2007) project is a Canadian population-level, longitudinal research project, in which teacher ratings of Kindergarten children’s early development and wellbeing are linked to health and academic achievement variables at the individual level, and to demographic, cultural, and socioeconomic variables at the community level. In this article, we draw from Bronfenbrenner’s bioecological theory of human development to create a coherent theoretical framework for guiding validation research within a population-level approach to child development research in general and for the EDI project in particular. The discussion draws from a range of social and health sciences as well as validity theory. The paper seeks to align complex conceptual, theoretical, methodological, and psychometric considerations, to provide specific design, methodology, and validation recommendations for a population-level approach to studying children’s development and wellbeing, and to discuss the strengths and challenges of this approach.  相似文献   
995.
Business Process Reengineering (BPR) has been a major catalyst of the pervasive organizational change we have witnessed over the past decade. Although one can speculate on the reasons for the popularity of this phenomenon, it is important that we carefully examine its underlying antecedents for initiation, implementation, and ultimately success, if we are to add value to practitioners of this concept. This study empirically examines the importance of facets of the organizational structure, IT knowledge resources and infrastructure, and the IS function in the initiation of BPR. Data from 313 corporations were gathered using a carefully validated survey, and initiators were compared with noninitiators. The results strongly suggest that client-server architectures, the strategic integration of IS, and cross departmental interaction are among the more important factors facilitating initiation and can be important inputs in a BPR decision-making process. The study attempts to build a contingent theory for BPR, and the more sustainable notion of fundamental process change.  相似文献   
996.
石丹理  韩晓燕  邓敏如 《社会》2005,25(3):70-100
在社会科学的历史中,定量和定性研究的争论持续了差不多半个世纪。随着研究者对实证主义的质疑,质性研究的数目逐渐增加。根据布瑞曼(Bryman,1988)的看法,质性研究有以下特点:(1)透过被访者的眼睛看世界;(2)描述日常生活情境的细节;(3)了解在不同社会范畴的背景中的行为及意义;(4)强调过程;(5)倾向采用文字及结构灵活的研究设计;(6)尽量避免在研究初期确立理论和观念。邓泽和林肯(Denzin & Lincoln,1998)也指出,质性研究有以下元素:(1)采用多元的研究手法;(2)涉及自然和诠译的角度;(3)在自然的情况下作出研究;(4)尝试理解和分析不同现象的…  相似文献   
997.
998.
Young people who are currently or were previously in state care have consistently been found to have much higher rates of mental health and neurodevelopmental difficulties than the general youth population. While a number of high-quality reviews highlight what research has been undertaken in relation to the mental health of young people with care experience and the gaps in our knowledge and understanding, there is, until now, no consensus, so far as we aware, as to where our collective research efforts should be directed with this important group. Through a series of UK wide workshops, we undertook a consultative process to identify an agreed research agenda between those with lived experience of being in care (n = 15), practitioners, policy makers and researchers (n = 59), for future research regarding the mental health of young people with care experience, including those who are neurodiverse/have a neurodevelopmental difficulty. This consensus statement identified 21 foci within four broad categories: how we conceptualize mental health; under-studied populations; under-studied topics; and underused methodologies. We hope that those who commission, fund and undertake research will engage in this discussion about the future agenda for research regarding the mental health of young people with care experience.  相似文献   
999.
Little is known about factors associated with child welfare case duration. Understanding factors associated with case duration may help stakeholders make more informed decisions about funding and service allocation and improve compliance with federal law. This study had two research questions: (1) What factors are associated with child welfare case duration? And (2) Do factors differ depending on whether children were placed exclusively with parents or with others (e.g. relatives and foster care) during the case? The study sample consisted of families (N = 874) with co-occurring child maltreatment and substance use in one midwestern state in the United States between 2007 and 2016. Linear regression models were used to identify correlates of case duration while controlling for child placement status. Overall, having a child under 1 year of age, benzodiazepine use, methamphetamine use and injection drug use were all associated with longer case duration, whereas marijuana use with no other substance use was associated with shorter case duration. Additionally, factors associated with case duration differed based on child placement status during the case. These findings suggest important heterogeneity in families involved with child welfare services and may allow for proactive mitigation of cases at greater risk.  相似文献   
1000.
Joint attention (JA), infants' ability to engage in triadic attention with another person and a separate object or event, emerges in infancy. Responding to joint attention (RJA) develops earlier than initiating joint attention (IJA) and may benefit from a reconceptualization from a competence to a skill that varies in performance. Investigating associations between RJA performance and important skills of toddlerhood such as language, social responsiveness, and executive function (EF) in typically developing samples can better elucidate how RJA may serve as a developmental precursor to later dimensional skills, with implications for both typical and atypical development. Here, 210 (82% White) infants completed the Dimensional Joint Attention Assessment (DJAA), a naturalistic play-based assessment of RJA, at 8–15 months. At 16–38 months social responsiveness, verbal ability, and EF were assessed. Multilevel models showed that DJAA scores were associated with later verbal abilities and parent-reported social responsiveness. Exploratory analyses showed trend-level associations between RJA and EF. Results establish the content validity of the DJAA as a measure of RJA, and longitudinal associations with later verbal ability and social responsiveness. Future work should examine EF emergence and consolidation, and RJA and later EF associations.  相似文献   
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