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排序方式: 共有1202条查询结果,搜索用时 62 毫秒
1.
In studies with recurrent event endpoints, misspecified assumptions of event rates or dispersion can lead to underpowered trials or overexposure of patients. Specification of overdispersion is often a particular problem as it is usually not reported in clinical trial publications. Changing event rates over the years have been described for some diseases, adding to the uncertainty in planning. To mitigate the risks of inadequate sample sizes, internal pilot study designs have been proposed with a preference for blinded sample size reestimation procedures, as they generally do not affect the type I error rate and maintain trial integrity. Blinded sample size reestimation procedures are available for trials with recurrent events as endpoints. However, the variance in the reestimated sample size can be considerable in particular with early sample size reviews. Motivated by a randomized controlled trial in paediatric multiple sclerosis, a rare neurological condition in children, we apply the concept of blinded continuous monitoring of information, which is known to reduce the variance in the resulting sample size. Assuming negative binomial distributions for the counts of recurrent relapses, we derive information criteria and propose blinded continuous monitoring procedures. The operating characteristics of these are assessed in Monte Carlo trial simulations demonstrating favourable properties with regard to type I error rate, power, and stopping time, ie, sample size. 相似文献
2.
William S. Meyer 《Clinical Social Work Journal》2002,30(3):311-328
Over the years, noteworthy social workers have been interviewed for the Clinical Social Work Journal. This article features an interview with Joyce Edward who is recognized for her many extraordinary contributions to clinical social work. Joyce has co-written or co-edited three exceptional books for the social work clinician, she has been an esteemed teacher and a vocal activist for quality mental health care. In this interview Joyce reflects on family influences, her work as a social caseworker, the psychoanalytic luminaries with whom she trained, her concerns about the clinical education of today's social work students, and finally, her perspective on managed mental health care. 相似文献
3.
有机污染物降解的光化学及微生物降解方法探索 总被引:1,自引:1,他引:0
谢丰 《东华理工学院学报》2002,21(2):22-27
随着塑料用途的不断扩大和消费量的日益增长,塑料废弃物也与日俱增,环境污染和社会公害等问题也日趋严重。塑料废弃物具有不易降解性,它不仅污染环境(土壤、水源等),还会阻止其它物质的降解。文章试图从基本机理入手,找到有机物降解的最有效途径,以达到保护环境、节约能源的目的。 相似文献
4.
关于高校实验室建设的几点思考 总被引:24,自引:1,他引:23
丁鸣 《南京工程学院学报(社会科学版)》2002,2(3):67-70
为把高校实验室建成开放式的创新实践基地 ,更好地发挥其在教学、科研、生产等方面的重要作用 ,应加强对高校实验室的硬件建设 ,并进行科学的统筹规划 ,加速提升实验室整体实力 ;加强实验教学师资队伍建设 ,实现实验室建设的跨越式发展 相似文献
5.
Conservation biology aims at assessing the status of a population, based on information which is often incomplete. Integrated population modelling based on state‐space models appears to be a powerful and relevant way of combining into a single likelihood several types of information such as capture‐recapture data and population surveys. In this paper, the authors describe the principles of integrated population modelling and they evaluate its performance for conservation biology based on a case study, that of the black‐footed albatross, a northern Pacific albatross species suspected to be impacted by longline fishing 相似文献
6.
加强实验室建设与管理 适应创新人才培养需要 总被引:7,自引:0,他引:7
党传升 《北京邮电大学学报(社会科学版)》2003,5(2):45-47
高校实验室在培养具有创新精神和实践能力的高素质专门人才方面,正越来越发挥着重要的和不可替代的作用.本文结合高校实际,从管理体制、管理规范、队伍建设、实验教学改革等方面对加强教学实验室建设与管理进行了有益的探索. 相似文献
7.
8.
高校实验室管理与评估 总被引:2,自引:0,他引:2
本文阐述了在评估工作的推动下 ,如何加强对实验人员队伍建设、建立和完善各种规章制度的管理 ,并对实验室评估工作做了科学的总结。 相似文献
9.
刘方农 《西昌学院学报(社会科学版)》2003,15(2):120-121
垂叶榕是城市绿化和园林造景中应用的一种重要树种,本文就垂叶榕的生物学习性及在绿化和盆景制作中的管理技术作一简要概述。 相似文献
10.
Summary Based on 14 case studies of highly effective therapies and the reasons they succeeded less frequently than they could, we
propose a variety of steps to improve the health care system of the U.S.A. Whatever proposal emerges from current national
debates until innovations are shown to be safe and effective, they should not be supported; when slightly better technologies
are much more expensive than other good ones we need to consider appropriate choices carefully; simplified billing and bookkeping
would reduce our costs; when a technology is rapidly introduced cautionnary measures may be needed; tracking immunization
and repairing their omissions requires a new system; educational programs such as seen effective in hypertension should be
applied in other areas such as vaccination; in organ transplantation the nation should consider “presumed consent”; our payment
system sometimes creates perverse incentives and therefore needs review; and the preferences of the public in allocation of
health resources need to be discovered once the public is informed about the issues.
Research supported by Andrew W. Mellon Foundation. 相似文献