Why are we waiting? The demography of adoption for children of black,Asian and black mixed parentage in England

The known shortage of adopters for children of black, Asian and black mixed parentage poses many dilemmas for practitioners, not least because of the potentially damaging consequences of delay while placements are sought. Drawing on a study of agency policy and practice in the recruitment of a larger, more diverse pool of adopters, this paper explores the demography of adoption for children of black, Asian and black mixed parentage. The paper suggests that the adoption prospects of children of some ethnic and religious groups may be affected by the young age structures of their populations. The age profiles and presenting needs of looked after children also vary between ethnic groups, putting some groups at a relatively greater disadvantage in terms of their adoption chances. At the same time, the paper considers the environmental and family factors that may affect the recruitment of a more diverse pool of adopters, and highlights the difficulties of achieving a balance between adopters’ expectations and the needs of waiting children. It concludes that more culturally sensitive and proactive recruitment strategies are needed, together with targeted, creative approaches to meet the placement needs of those children of black, Asian or mixed parentage who currently wait longest.     

量子力学统计性的根源

在经典极限讨论量子力学波函数的分布函数，经典力学单粒子体系与经典力学均匀系综在相空间中的分布函数。说明量子力学波函数不能描述单粒子体系，而只能描述系综。这就是量子力学统计性的根源。     

浅地层探地雷达回波倒相的自适应处理

针对浅地层探地雷达目标回波相位倒置造成的垂直距离判别不准的问题,提出了一种探地雷达对目标回波相位倒置的自动识别、纠正并统一成像的方法。讨论了均匀平面波对理想导体和理想介质平面垂直入射情况下,反射平面对反射波相位的影响。介绍了探地雷达信号处理的算法,对实测的成像数据进行处理,证明了该算法的有效性,提高了浅地层探地雷达在存在相位倒置情况下的检测能力。     

看·说·女人的示众--谈现当代文学作品中女人的两种“示众”

女人"示众"的情节是20世纪30、40年代和90年代一些女作家笔下都描述了的,但由于时代环境、社会体制以及作家价值取向的差异,使得"示众"本身负载着太多的历史内涵和文化元素。在男权文化仍然占据人类文化制高点的时代里,对这两种"示众"的探究,势必引发人们关于社会表情与女性生存状态之间的复杂多元态势的思考。     

日本电视产业的特点与发展脉络

日本电视产业呈现出以日本放送协会为代表的公营电视媒体和以日本民间放送联盟所属的各日本商业电视台两足鼎立的结构特点;产业中两种体制的运营理念、营运方式和决策管理机构大相径庭。日本电视产业从初始到壮大,从无线电视、有线电视到卫星电视、数字电视,从大众传播到专门化以及分众传播,经历了若干发展阶段。     

基于可编程逻辑器件的DDS设计

给出了基于FPGA芯片的直接数字频率合成器(DDS)的设计方法,利用FPGA的高速、高性能及可重构性,根据需要可方便地实现各种比较复杂的调频、调相和调幅功能,在现代通信系统中具有良好的实用性.     

Effect of design specifications in dose‐finding trials for combination therapies in oncology

Model‐based dose‐finding methods for a combination therapy involving two agents in phase I oncology trials typically include four design aspects namely, size of the patient cohort, three‐parameter dose‐toxicity model, choice of start‐up rule, and whether or not to include a restriction on dose‐level skipping. The effect of each design aspect on the operating characteristics of the dose‐finding method has not been adequately studied. However, some studies compared the performance of rival dose‐finding methods using design aspects outlined by the original studies. In this study, we featured the well‐known four design aspects and evaluated the impact of each independent effect on the operating characteristics of the dose‐finding method including these aspects. We performed simulation studies to examine the effect of these design aspects on the determination of the true maximum tolerated dose combinations as well as exposure to unacceptable toxic dose combinations. The results demonstrated that the selection rates of maximum tolerated dose combinations and UTDCs vary depending on the patient cohort size and restrictions on dose‐level skipping However, the three‐parameter dose‐toxicity models and start‐up rules did not affect these parameters. Copyright © 2016 John Wiley & Sons, Ltd.     

Do single‐arm trials have a role in drug development plans incorporating randomised trials?

Often, single‐arm trials are used in phase II to gather the first evidence of an oncological drug's efficacy, with drug activity determined through tumour response using the RECIST criterion. Provided the null hypothesis of ‘insufficient drug activity’ is rejected, the next step could be a randomised two‐arm trial. However, single‐arm trials may provide a biased treatment effect because of patient selection, and thus, this development plan may not be an efficient use of resources. Therefore, we compare the performance of development plans consisting of single‐arm trials followed by randomised two‐arm trials with stand‐alone single‐stage or group sequential randomised two‐arm trials. Through this, we are able to investigate the utility of single‐arm trials and determine the most efficient drug development plans, setting our work in the context of a published single‐arm non‐small‐cell lung cancer trial. Reference priors, reflecting the opinions of ‘sceptical’ and ‘enthusiastic’ investigators, are used to quantify and guide the suitability of single‐arm trials in this setting. We observe that the explored development plans incorporating single‐arm trials are often non‐optimal. Moreover, even the most pessimistic reference priors have a considerable probability in favour of alternative plans. Analysis suggests expected sample size savings of up to 25% could have been made, and the issues associated with single‐arm trials avoided, for the non‐small‐cell lung cancer treatment through direct progression to a group sequential randomised two‐arm trial. Careful consideration should thus be given to the use of single‐arm trials in oncological drug development when a randomised trial will follow. Copyright © 2015 The Authors. Pharmaceutical Statistics published by JohnWiley & Sons Ltd.     

青少年厌学现象成因及应对策略

厌学作为一种心理状态,是所有学生在某种程度上共同潜在的问题。厌学现象背后的成因错综复杂,社会、学校、家庭应共同致力创造一个好的成长环境,建构有效的情感疏导和心理辅导模式,重视青少年“自我同一性”心理的发展,发挥体育和美育在矫正厌学心理中的作用     

捷便频调频发射机原理与实现

介绍了典型调频发射机的基本工作过程及存在的不足，对其频点单一、功率固定、调试困难等缺陷加以说明，给出了采用捷便频调频发射机的解决方案，就其系统组成，重点对载波信号发生器、功率放大器、天线及主控电路进行了阐述．