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681.
In this study, we investigated if the association between parental divorce and depressive symptoms changes during early adolescence and if developmental patterns are similar for boys and girls. Data were collected in a prospective population cohort of Dutch adolescents (N = 2,149), aged 10 – 15 years. Outcome variables were self‐reported and parent‐reported depressive symptoms. The effects of divorce were adjusted for parental depression. In both self‐reported and parent‐reported data, we found a three‐way interaction of gender, age, and parental divorce, indicating that with increasing age, parental divorce became more strongly associated with depressive symptoms among girls, but not boys. These results suggest that girls with divorced parents are at particularly high risk to develop depressive symptoms during adolescence.  相似文献   
682.
The nature of competition imposes a fundamental re-examination of strategies, both at the corporate and business level. Observation of a large number of firms reveals changes aimed at creating more permeable boundaries for breaking down costs, while increasing efficiency in product innovation and manufacturing. What appears to be relevant in many of these efforts is the emergence of transnational organisational architectures (TOA) in which the value-generating activities are distributed among different countries and actors, and then recomposed at the corporate level without losing efficiency. In this paper, we put forward the proposition that relational capability represents a distinctive competence for the transnational firm. The ability to access new knowledge or complementary capabilities, and to leverage inter-firm relationships and opportunities wherever they arise emerges as a critical factor for success on a global scale.  相似文献   
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In the field of education, it is often of great interest to estimate the percentage of students who start out in the top test quantile at time 1 and who remain there at time 2, which is termed as “persistence rate,” to measure the students’ academic growth. One common difficulty is that students’ performance may be subject to measurement errors. We therefore considered a correlation calibration method and the simulation–extrapolation (SIMEX) method for correcting the measurement errors. Simulation studies are presented to compare various measurement error correction methods in estimating the persistence rate.  相似文献   
687.
Scholars from different disciplines acknowledge the importance of studying new service development (NSD), which is considered a central process for sustaining a superior competitive advantage of service firms. Although extant literature provides several important insights into how NSD processes are structured and organized, there is much less evidence on what makes NSD processes successful, that is, capable of contributing to a firm's sales and profits. In other words, which are the decisions that maximize the likelihood of developing successful new services? Drawing on the emerging “service‐dominant logic” paradigm, we address this question by developing an NSD framework with three main decisional nodes: market orientation, internal process organization, and external network. Using a qualitative comparative analysis technique, we discovered combinations of alternatives that maximize likelihood of establishing a successful service innovation. Specifically, we tested our NSD framework in the context of hospitality services and found that successful NSD can be achieved through two sets of decisions. The first one includes the presence of a proactive market orientation (PMO) and a formal top‐down innovative process, but the absence of a responsive market orientation. The second one includes the presence of both responsive and PMO and an open innovation model. No single element was a sufficient condition for NSD success, though PMO was a necessary condition. Several implications for theory and decision‐making practice are discussed on the basis of our findings.  相似文献   
688.
Repeated neuropsychological measurements, such as mini-mental state examination (MMSE) scores, are frequently used in Alzheimer’s disease (AD) research to study change in cognitive function of AD patients. A question of interest among dementia researchers is whether some AD patients exhibit transient “plateaus” of cognitive function in the course of the disease. We consider a statistical approach to this question, based on irregularly spaced repeated MMSE scores. We propose an algorithm that formalizes the measurement of an apparent cognitive plateau, and a procedure to evaluate the evidence of plateaus in AD using this algorithm based on applying the algorithm to the observed data and to data sets simulated from a linear mixed model. We apply these methods to repeated MMSE data from the Michigan Alzheimer’s Disease Research Center, finding a high rate of apparent plateaus and also a high rate of false discovery. Simulation studies are also conducted to assess the performance of the algorithm. In general, the false discovery rate of the algorithm is high unless the rate of decline is high compared with the measurement error of the cognitive test. It is argued that the results are not a problem of the specific algorithm chosen, but reflect a lack of information concerning the presence of plateaus in the data.  相似文献   
689.
Objective. This study investigates whether or not domestic violence agencies are located in areas of need. Recent research indicates that community economic disadvantage is a risk factor for intimate partner violence, but related questions regarding the geographic location of social service agencies have not been investigated.Methods. Using Connecticut as a case study, we analyze the relationship of agency location and police-reported domestic violence incidents and assaults using OLS regression and correcting for spatial autocorrelation.Results. The presence of an agency within a town has no relationship with the rates of domestic violence. However, regional patterns are evident.Conclusion. Findings indicate that programs are not geographically mismatched with need, but neither are programs located in towns with higher rates of incidents or assaults. Future research and planning efforts should consider the geographic location of agencies.  相似文献   
690.
In this note we introduce a graph problem, called Maximum Node Clustering (MNC). We prove that the problem (which is easily shown to be strongly NP-complete) can be approximated in polynomial time within a ratio arbitrarily close to 2. For the special case where the graph is a tree, the problem is NP-complete in the ordinary sense; for this case we present a pseudopolynomial algorithm based on dynamic programming, and a related Fully Polynomial Time Approximation Scheme (FPTAS). Also, the tree case is shown to be exactly solvable in time, where n is the number of nodes.  相似文献   
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