A Bayesian method for safety signal detection in ongoing blinded randomised controlled trials

Sponsors have a responsibility to minimise risk to participants in clinical studies through safety monitoring. The FDA Final Rule for IND Safety Reporting requires routine aggregate safety evaluation, including in ongoing blinded studies. We are interested in estimating the probability that the true adverse event rate in the experimental arm exceeds that in the control arm. We developed a Bayesian approach that specifies an informative meta-analytic predictive prior on the event probability in the control arm and an uninformative prior on that in the experimental arm. We combined these priors with a mixture likelihood that considers each patient in the ongoing blinded study may belong to the experimental or control arm. This allowed us to estimate the quantity of interest without unblinding. We evaluated our method by simulation, pairing scenarios that differed only in whether a safety signal was present or missing, and quantifying the ability of our model to discriminate using signal detection theory. Our approach shows benefit. It detects safety signals more reliably with greater sample sizes and for common rather than rare events. Performance does not deteriorate markedly when historical studies exhibit heterogeneous hazards or non-constant hazards. Our method will allow us to monitor safety signals in ongoing blinded studies with the goal of earlier identification and risk mitigation. Our method could be adapted to use informative priors on both arms or predictive covariates where pertinent data exist. We stress that ongoing safety monitoring should involve a multi-disciplinary team where statistical methods are paired with medical judgement.     

中央银行信息披露影响商业银行信贷供给吗？

在建设现代中央银行制度背景下,提高货币政策透明度,有效管理和引导预期尤为关键,这使得探索中央银行信息披露的经济后果同样成为辨析货币政策调控机制的重要研究方向。基于2008—2020年中国48家商业银行季度数据,运用文本分析法构建了中央银行信息披露指数,并实证分析了中央银行信息披露对商业银行信贷供给的影响。研究发现:中央银行信息披露越充分,商业银行信贷供给越大；特别地,正向信号越明显,中央银行信息披露对商业银行信贷供给的正向影响也越大；机制检验结果显示,中央银行信息披露通过影响商业银行的避险动机,调节商业银行的信贷供给。异质性分析表明,在资本充足率较低、规模较小、流动性较弱的商业银行中,中央银行信息披露对商业银行信贷供给的影响更大。因此,中央银行在不断提升信息披露质量的同时,也要打好信息披露与货币政策的“组合拳”,以达到最优的政策调控效果。     

地理距离对企业社会责任的影响研究

地理距离在中国转型经济情境下,意味着信息不对称和制度压力异质性。基于信号理论,以2010~2017年中国上市公司为样本,采用随机效应模型,探讨企业与政府监管机构之间的地理距离对企业社会责任的影响机理,以及制度环境与高铁线路对上述关系的调节效应。研究表明:地理距离对企业社会责任表现存在显著的负向影响,较好的制度环境与途经较多的高铁线路,均可缓解地理距离对企业社会责任表现的负向影响。     

核威慑机理:实力基础、信号传递和心理博弈

基辛格提出了威慑分析框架,认为威慑需要实力、使用实力的意志以及潜在的进攻者对这两方面因素的综合评估等三方面因素的结合,但他没有对这一分析框架进行深入分析。本文跳出从战略稳定性角度分析核威慑的传统思路,把认知和心理因素植入核威慑分析之中,对基辛格建构的威慑分析框架进行了细化,并将其用于核威慑分析,把威慑的三个构成要素置换为核实力基础、核威慑信号传递和核威慑心理博弈三个变量,把核威慑界定为在核力量基础上通过信号传递进行的心理博弈。影响核武器数量规模的因素分为国家政策因素、确定一国核武器数量的直接依据、国家资源约束和国际环境的影响。核威慑信号传递包括口头信号传递、书面信号传递、捆绑信号传递和行动信号传递四种方式,每一种传递方式各有其传递路径。在核威慑心理博弈部分,分析了对核威慑正确认知的形成机制,并在此基础上分析了核力量平衡国家间的核威慑心理博弈、核力量悬殊国家间的核威慑心理博弈和导弹防御系统对核威慑心理博弈的影响。分析核威慑中核力量与使用核力量意志的关系、描述核威慑过程中信号传递的方式与路径和威慑与被威慑双方的心理博弈过程,对于分析核威慑有效性、维持大国间战略稳定性,具有一定的理论价值和现实意义。     

低压电力载波农产品温度湿度多路报警器的设计

设计了一种以电力线载波为传输媒介的报警器,并对系统各部分原理进行了较为详细的分析.