Nonparametric density deconvolution by weighted kernel estimators

Nonparametric density estimation in the presence of measurement error is considered. The usual kernel deconvolution estimator seeks to account for the contamination in the data by employing a modified kernel. In this paper a new approach based on a weighted kernel density estimator is proposed. Theoretical motivation is provided by the existence of a weight vector that perfectly counteracts the bias in density estimation without generating an excessive increase in variance. In practice a data driven method of weight selection is required. Our strategy is to minimize the discrepancy between a standard kernel estimate from the contaminated data on the one hand, and the convolution of the weighted deconvolution estimate with the measurement error density on the other hand. We consider a direct implementation of this approach, in which the weights are optimized subject to sum and non-negativity constraints, and a regularized version in which the objective function includes a ridge-type penalty. Numerical tests suggest that the weighted kernel estimation can lead to tangible improvements in performance over the usual kernel deconvolution estimator. Furthermore, weighted kernel estimates are free from the problem of negative estimation in the tails that can occur when using modified kernels. The weighted kernel approach generalizes to the case of multivariate deconvolution density estimation in a very straightforward manner.     

质量建设是辅导员队伍建设的根本

辅导员工作在高校思想政治工作中居于重要地位。在新的历史时期,辅导员工作内容发生了根本性的改变,要求其从业人员具有更高的综合素质。加强辅导员队伍质量建设已成为高校思想政治工作中亟待解决的问题。     

英国农村发展模式对中国新农村建设的启示

农村发展模式是指农村发展的样式及所呈现的特点。在这个意义上,英国的农村发展道路走的是典型的内发变迁模式,即结合本国实际情况主要依靠本国自身力量来实现农业现代化和城乡一体化的一种方式。在中国建设社会主义新农村的关键时期,针对中国新农村建设在资金、组织方式等方面的实际情况和问题,英国农村发展模式的特征及经验,具有有益的借鉴启示。     

Race and opportunity in a public alternative school

This qualitative case-study explores questions about the stratifying role of public alternative schools created for ‘at-risk’ youth by analyzing the school experience of students who attend a single continuation high school and the process of student enrollment and referral to that school. Drawing on the concept of whiteness as property, this article demonstrates how the continuation high school maintained and protected the property functions of whiteness through acts of symbolic violence and the systematic removal of non-white students from the school district’s mainstream high school. Instead, students were placed in a substandard alternative school lacking in material and intellectual resources. Furthermore, teachers, counselors, and administrative staff at the mainstream and continuation high schools alike drew upon the racial ideology of merit to rationalize the overrepresentation of non-white youths at the study school and to ‘deracialize’ the student referral process.     

Emotions and cosmopolitan sociability: Barriers and opportunities for intercultural encounters amongst new Chinese migrants in New Zealand

Emotions matter, particularly in experiences of migration. This article explores how emotions are involved in everyday intercultural encounters and the role of emotions in generating cosmopolitan sociability in the context of migration. The article is based upon qualitative research with 80 Chinese 1st and 1.5 generation migrants in New Zealand. We focus on ‘contact zones’ as social spaces where migrants have uneven opportunities to encounter cultural others and where ‘emotional dissonance’ can emerge through unsuccessful intercultural exchanges. In order to generate a sense of comfort and familiarity in such conflicted spaces, migrants need to invest in ‘emotional labour’ to engage in more cosmopolitan sociability as an attempt to transform ‘contact zone’ to ‘comfort zone’. Through this article we argue that emotions can both promote and encourage, but also undermine and limit the capacity to perform cosmopolitan sociability and build intercultural relations.     

Bullying and Victimization Among Young Elementary School Children: The Role of Child Ethnicity and Ethnic School Composition

School-aged children with an ethnic minority background are relatively often involved in bullying and victimization, but the role of ethnic composition of schools in this context remains unclear. This study examined the relation between ethnic minority background, ethnic school composition, and bullying behaviour around primary school entry in the Netherlands. The study was based on a 2008/2009 school survey in Rotterdam, a Dutch city where about 50 % of children have a non-Dutch background. For 8523 children, teacher reports of bullying behaviour at age 5–6 years were available. Children with a non-Dutch background had higher odds of being a victim (adjusted OR 1.41, 95 % CI 1.11, 1.80), bully (OR 1.38, 95 % CI 1.20, 1.58) or bully-victim (OR 1.38, 95 % CI 1.19, 1.62) than children of Dutch national origin. Ethnic diversity in schools increased children’s risk of bullying behaviour (e.g. OR_victim per 0.1 increase in 0–1 diversity range = 1.06, 95 % CI 1.00, 1.13), with children of both Dutch and non-Dutch national origin relatively more often involved in bullying in ethnically diverse schools. The proportion of same-ethnic peers in school reduced the risk of bullying among children of Dutch national origin (e.g. OR_victim per 10 % more same-ethnic children = 0.90, 95 % CI 0.83, 0.98), but not among non-Dutch children. In conclusion, ethnic minority background and ethnic diversity within schools are risk factors for bullying among 5–6 year olds. Plausibly, reductions in absolute numbers of bullying events may be obtained with tailor-made interventions in ethnically diverse schools. Such interventions should preferably be offered early in the school curriculum.     

Deconstructing Immigrant Illegality: A Mixed-Methods Investigation of Stress and Health Among Undocumented College Students

Research has established that being undocumented is a risk factor for mental and physical health conditions. Much of this work emphasizes undocumented immigrants’ chronic stress, yet key questions about pathways to health remain. The mere state of being undocumented is viewed as a general stressor, without considering actual levels of stress or identifying dimensions of documentation status that contribute to overall stress levels. Drawing on surveys and interviews with undocumented students at the University of California, we uncover the everyday manifestations of four dimensions of immigrant “illegality”: academic concerns, future concerns, financial concerns, and deportation concerns, and their association with reported stress levels and self-rated health. Survey data establish undocumented students’ high levels of stress and poorer health, in comparison to previous research on other national samples. In a structural equation model, we found academic and future concerns to be significantly associated with higher stress, which was in turn, associated with poorer self-rated health. Financial concerns were not associated with higher perceived stress but were directly associated with poorer self-rated health. Notably, deportation concerns did not have any significant independent associations with stress or health. We use our qualitative data to identify specific stressors embedded within these four dimensions. Our findings inform understandings of the health risks arising from documentation status.     

Women–Family in Quality Perspective

Bringing together women and family in quality perspective bring about interesting discussions in this paper. By integrating previous studies and considering expert opinions, we determinate the variables and dimensions with respect to women’s existence regarding their roles both in the family and at work. Many activities carried out by women represent the consumer aspects of their role. Women undertake these activities to fulfill their needs, which can be classified in the order of preference using Maslow’s Hierarchy of Need. Women success can be measured based on their ability to perform their roles successfully. We identify women’s performance by using quality approach of Personal Quality Maintenance (PQM), which is widely applied in many organizations in order to maintain the service delivery, which meets the customer satisfaction. The effort to enhance women’s satisfaction for their success in playing the multirole in the family and at work is our main consideration. This study may contribute a new point of view regarding for the women’s welfare and existence.     

Age at marriage and marital instability: revisiting the Becker–Landes–Michael hypothesis

An early age at first marriage is known to be associated with a high risk of divorce. Yet, it has been suggested that beyond a certain point, the relationship between age at marriage and marital instability may become positive because as unmarried women begin to hear their biological clock tick, they may settle for matches far from the optimal. Analyses based on cycles 5 and 6 of the National Surveys of Family Growth show that the relationship between age at marriage and marital instability is strongly negative up to the late 20s, with a flattening of the curve thereafter.

Testing Evolutionary Hypotheses with Demographic Data

An ecological evolutionary viewpoint offers new perspectives on contemporary demographic problems in general and on population–environment issues in particular. In turn, rich and detailed human demographic data can help solve problems of interest in evolutionary theory. Such data have been analyzed in greatest detail in studies of traditional and historical societies. Evolutionary approaches using historical data go beyond small‐sample anthropological studies to the application of the evolutionary approach to large datasets, and illuminate important similarities between small‐scale traditional societies and large modern populations living in evolutionarily novel environments. This article provides a concise update of the breadth of questions and hypotheses of likely interest to demographers and others that evolutionary theorists address using a variety of traditional and historical datasets. It suggests opportunities for additional collaborative work between evolutionary theorists and historical demographers and highlights topics relevant to modern demography.