“Helping teenagers in care flourish: What parenting research tells us about foster care”

In this article, I review a range of theoretical and practical issues that are relevant to the foster care of teenagers. I argue that topics such as the recent research evidence from neuroscience regarding brain development in adolescence, as well as control, the promotion of autonomy, and resilience, all have major implications for the provision of appropriate care for teenagers. I outline some of the key conclusions reached by researchers on these pertinent topics and then go on to consider the implications from this evidence for the training of foster carers.     

A novel approach based on multiple correspondence analysis for monitoring social networks with categorical attributed data

In in most cases, the distribution of communications is unknown and one may summarize social network communications with categorical attributes in a contingency table. Due to the categorical nature of the data and a large number of features, there are many parameters to be considered and estimated in the model. Hence, the accuracy of estimators decreases. To overcome the problem of high dimensionality and unknown communications distribution, multiple correspondence analysis is used to reduce the number of parameters. Then the rescaled data are studied in a Dirichlet model in which the parameters should be estimated. Moreover, two control charts, Hotelling’s T² and multivariate exponentially weighted moving average (MEWMA), are developed to monitor the parameters of the Dirichlet distribution. The performance of the proposed method is evaluated through simulation studies in terms of average run length criterion. Finally, the proposed method is applied to a real case.     

Generalized phase I-II designs to increase long term therapeutic success rate

Designs for early phase dose finding clinical trials typically are either phase I based on toxicity, or phase I-II based on toxicity and efficacy. These designs rely on the implicit assumption that the dose of an experimental agent chosen using these short-term outcomes will maximize the agent's long-term therapeutic success rate. In many clinical settings, this assumption is not true. A dose selected in an early phase oncology trial may give suboptimal progression-free survival or overall survival time, often due to a high rate of relapse following response. To address this problem, a new family of Bayesian generalized phase I-II designs is proposed. First, a conventional phase I-II design based on short-term outcomes is used to identify a set of candidate doses, rather than selecting one dose. Additional patients then are randomized among the candidates, patients are followed for a predefined longer time period, and a final dose is selected to maximize the long-term therapeutic success rate, defined in terms of duration of response. Dose-specific sample sizes in the randomization are determined adaptively to obtain a desired level of selection reliability. The design was motivated by a phase I-II trial to find an optimal dose of natural killer cells as targeted immunotherapy for recurrent or treatment-resistant B-cell hematologic malignancies. A simulation study shows that, under a range of scenarios in the context of this trial, the proposed design has much better performance than two conventional phase I-II designs.     

现代汉语时相之系统功能视角研究

以往对现代汉语时相的研究集中在动词本身,着眼于动词本身的时间意义,并且缺乏系统的理论指导。文章以系统功能语言学为研究视角,对不同过程类型小句的时相特征进行分析和讨论。研究表明:谓体为小句时相的表达提供了基本的可能性,如果没有其他成分的影响,谓体表达的时间意义则决定小句的时相特征;小句其他句法成分有时对时相起着重要的影响作用。      

对拉美国家现代化几个阶段的认识

拉美国家从19世纪下半叶步入现代化的历史进程以来,先后经历了现代化的初始阶段、自主发展阶段、快速发展阶段和调整阶段。探索这一现代化的演进过程,有助于我们从整体上把握拉美国家现代化的进程和发展脉络,从中吸取对发展中国家现代化建设一些有益启示。     

Two-stage phase II trials with early stopping for effectiveness and safety as well as ineffectiveness or harm

This article proposes new optimal and minimax designs, which allow early stopping not only for ineffectiveness or toxicity but also for sufficient effectiveness and safety. These designs may facilitate effective drug development by detecting sufficient effectiveness and safety at an early stage or by detecting ineffectiveness or excessive toxicity at an early stage. The proposed design has advantage over other designs in the sense that it can control the type I error rate and is robust against the real association parameter. Comparing to Jin's design, it is always advantageous in terms of expected sample size.     

Shards of the old looking glass: restoring the significance of identity in promoting positive outcomes for looked‐after children

There is a driving force within current UK child welfare policies which promotes a strengths led approach to both assessment and care planning for children in need. Social policy emphasizes the importance of tangible outcomes such as education achievement, which have been enshrined in statute. However, other developmental outcomes, such as identity, are subordinated. Notwithstanding the relevance of these more concrete indicators, this paper suggests that this focus has left a gap at theoretical, strategic and operational levels relating to more psychosocial aspects of human growth and development, such as identity. This paper seeks to redress that gap by considering identity as both a process and an outcome. Following a review of the literature on identity development, it presents an analysis of semi‐structured interviews with 13 young people and their social workers. The findings show how young people's identity is shaped by their relationships, can be a protective mechanism, and deferred or put on standby. In the concluding discussion the implications for social work practice are highlighted.     

Prediction of accrual closure date in multi-center clinical trials with discrete-time Poisson process models

In a phase III multi‐center cancer clinical trial or a large public health study, sample size is predetermined to achieve desired power, and study participants are enrolled from tens or hundreds of participating institutions. As the accrual is closing to the target size, the coordinating data center needs to project the accrual closure date on the basis of the observed accrual pattern and notify the participating sites several weeks in advance. In the past, projections were simply based on some crude assessment, and conservative measures were incorporated in order to achieve the target accrual size. This approach often resulted in excessive accrual size and subsequently unnecessary financial burden on the study sponsors. Here we proposed a discrete‐time Poisson process‐based method to estimate the accrual rate at time of projection and subsequently the trial closure date. To ensure that target size would be reached with high confidence, we also proposed a conservative method for the closure date projection. The proposed method was illustrated through the analysis of the accrual data of the National Surgical Adjuvant Breast and Bowel Project trial B‐38. The results showed that application of the proposed method could help to save considerable amount of expenditure in patient management without compromising the accrual goal in multi‐center clinical trials. Copyright © 2012 John Wiley & Sons, Ltd.     

相位旋转的速率为2的空时分组码

速率为2的空时分组码(R2-STBC)能达到全速率全分集,然而其译码复杂度与调制阶数的平方成正比。为了降低译码复杂度,提出了一种基于相位旋转的、速率为2的空时分组码(PR-R2-STBC),发送端根据反馈信息将部分发送信号旋转一定的角度,实现了信号在传输过程中两两正交,从而使得其译码复杂度与调制阶数成正比。仿真结果显示,与R2-STBC相比,该编码仅需反馈7 bit就极大地降低了译码复杂度。