RELATIVE EFFECTS OF WHOLE-WORD AND PHONETIC-PROMPT ERROR CORRECTION ON THE ACQUISITION AND MAINTENANCE OF SIGHT WORDS BY STUDENTS WITH DEVELOPMENTAL DISABILITIES

We used an alternating treatments design to compare the effects of two procedures for correcting student errors during sight word drills. Each of the 5 participating students with developmental disabilities was provided daily one-to-one instruction on individualized sets of 14 unknown words. Each week's new set of unknown words was divided randomly into two groups of equal size. Student errors during instruction were immediately followed by whole-word error correction (the teacher stated the complete word and the student repeated it) for one group of words and by phonetic-prompt error correction (the teacher provided phonetic prompts) for the other group of words. During instruction, all 5 students read correctly a higher percentage of whole-word corrected words than phonetic-prompt corrected words. Data from same-day tests (immediately following instruction) and next-day tests showed the students learned more words taught with whole-word error correction than they learned with phonetic-prompt error correction.     

Discrete and continuous measures of dimensional stimulus control

In two sets of experiments, we examined dimensional stimulus control of pigeons' responses to a visual flicker-rate continuum. In the first experiment, responses to a single key were reinforced periodically during stimuli from one half of the stimulus continuum, and responses during other stimuli were extinguished. In the second experiment, two response keys were simultaneously available, with reinforcement for each response alternative associated with different halves of the stimulus continuum. Conditions of the second experiment involved either free-operant or discrete-trial stimulus presentations. Results from these experiments show that positive dimensional contrast appeared in discrimination tasks with one or two response alternatives, but only with free-operant procedures. In addition, discrimination between stimulus classes established by differential reinforcement was assessed as accurately by continuous rate measures as by discrete response choice in the two-alternative situation. The general implication of these experiments is that response rate measures, when properly applied, may reveal sources of variation within stimulus classes, such as dimensional contrast, that are not evident with discrete measures.     

The role of randomised controlled trials in developing an evidence‐base for counselling and psychotherapy

Background: Representatives of counselling and person‐centred organisations indicate many of their members feel their profession and orientation is under threat, with counselling services being decommissioned in NHS settings. Aims: To understand the views of key figures in the psychological therapies field (policy makers, researchers and representatives of the counselling community) towards randomised controlled trials (RCTs), and their present and future role in developing the evidence‐base for counselling and psychotherapy. Method: Interviews (phone, Skype or face‐to‐face) were conducted with 24 authorities in the field. Relevant practitioner and academic networks were also contacted and key documents in the field were reviewed. Results: Key figures believe that RCTs will continue to play a decisive role in determining which psychological interventions are recommended and commissioned within the NHS for the foreseeable future. Other methods are seen as having some validity, but are generally considered supplementary to RCTs and not a replacement for them. Discussion: Although many members of the counselling community are critical of RCTs, they are likely to remain the mainstay of commissioning policy for some years to come. This means, in the coming years, members of the counselling community may face difficult choices in how to promote their work, while maintaining their core principles and values.     

Psychological Contract in HIV Prevention Clinical Trials in Resource Poor Communities in Africa

The paper explored the application of psychological contract in HIV prevention clinical trials in resource poor communities in Africa. The psychological contract was discussed in relation to practices in New HIV Prevention Technologies in Africa. From this discussion, it would seem risk for exposure to HIV infection is less well articulated in the psychological contract between the promoters of HIV prevention clinical trials and participants in resource poor communities in Africa. The trialing of New HIV Prevention Technologies in Africa should have in-built psychological contract transparency to reduce the risk of participant exposure to HIV infection in clinical trials.     

Slouching Toward Policy: Lazy Bioethics and the Perils of Science Fiction

Too much contemporary bioethical discourse is weak on science, lazily citing and adopting science fiction scenarios rather than science facts in the framing of analyses and policies. We challenge bioethicists to take more seriously the role of providing informed insight into and oversight over contemporary science and its implications and applications. Bioethicists must work harder to understand the fast-changing truths and limits of basic science, and they must incorporate only appropriate and authentic science into their discourse, just as they did in the past when addressing the quandaries of clinical medicine. The field of bioethics is not so old and entrenched that its future is assured. Bioethicists must make themselves useful to society in order to deserve and retain the public's trust. They can best do this by ensuring that decision making and public policy are grounded in facts, not fictions and fantasies.     

症状性颈动脉狭窄CEA治疗时机的Meta分析

评估症状性颈动脉狭窄（SCAS）患者颈动脉内膜剥脱术（CEA）手术时机选择及伴发症状对预后的影响.通过相关检索策略查找探讨CEA手术时机选择对于患者预后影响的随机对照试验.所有数据均采用Revman5.0分析软件进行Meta分析.纳入22篇文献,总计9 037名患者.Meta分析结果显示：SCAS患者4w、2w、1w 前后行CEA术后卒中再发率或死亡率组间无统计学差异.合并脑卒中的患者4w、2w 前后及合并短暂性脑缺血发作（TIA）或心肌梗死（MI）的患者4w前后行CEA术后卒中再发率或死亡率无统计学差异.症状稳定的SCAS患者应尽早行CEA术,伴发症状脑卒中、TIA 和MI不影响手术预后.     

Selecting the Right Tool For the Job

There are competing ethical concerns when it comes to designing any clinical research study. Clinical trials of possible treatments for Ebola virus are no exception. If anything, the competing ethical concerns are exacerbated in trying to find answers to a deadly, rapidly spreading, infectious disease. The primary goal of current research is to identify experimental therapies that can cure Ebola or cure it with reasonable probability in infected individuals. Pursuit of that goal must be methodologically sound, practical and consistent with prevailing norms governing human subjects research. Some maintain that only randomized controlled trials (RCTs) with a placebo or standard-of-care arm can meet these conditions. We maintain that there are alternative trial designs that can do so as well and that sometimes these are preferable to RCTs.     

Handling Missing Covariates in Conditional Mixture Models Under Missing at Random Assumptions

Mixture modeling is a popular method that accounts for unobserved population heterogeneity using multiple latent classes that differ in response patterns. Psychologists use conditional mixture models to incorporate covariates into between-class and/or within-class regressions. Although psychologists often have missing covariate data, conditional mixtures are currently fit with a conditional likelihood, treating covariates as fixed and fully observed. Under this exogenous-x approach, missing covariates are handled primarily via listwise deletion. This sacrifices efficiency and does not allow missingness to depend on observed outcomes. Here we describe a modified joint likelihood approach that (a) allows inference about parameters of the exogenous-x conditional mixture even with nonnormal covariates, unlike a conventional multivariate mixture; (b) retains all cases under missing at random assumptions; (c) yields lower bias and higher efficiency than the exogenous-x approach under a variety of conditions with missing covariates; and (d) is straightforward to implement in available commercial software. The proposed approach is illustrated with an empirical analysis predicting membership in latent classes of conduct problems. Recommendations for practice are discussed.     

药物临床试验设计的伦理思考

目前广泛采用的药物临床试验设计中,由于不能使受试者最大限度的受益而在伦理学方面存在弊端。自适应设计方法的出现,为克服这一弊端提供了现实途径,可使药物临床试验的受试者能够最大程度的受益。本文从传统临床试验引发的伦理问题入手,阐述了自适应设计以人为本的特点,探讨了其在解决伦理与疗效冲突问题中的重要作用。     

难度与分值对高一学生选择停止、集中或分散学习的影响

选取50名高一学生,选用反义词对和人工词对两种学习材料,赋予学习材料不同的分值,探讨项目难度和分值对学习者集中学习或分散学习选择及其效果的影响,并通过问卷调查被试对不同学习方式的认识。结果发现:(1)只有44%的被试报告分散学习更有效,被试总体上也更多地选择了集中学习;(2)在困难项目上,分散学习比集中学习的效果更好;(3)被试对容易项目更多选择停止学习,对困难项目更少选择停止学习,特别是困难高分项目;对困难项目比对容易项目更多选择分散学习,而在困难与容易项目上,对集中学习的选择不存在显著差异。