Predictive Bayesian Microbial Dose-Response Assessment Based on Suggested Self-Organization in Primary Illness Response: Cryptosporidium parvum

The probability of illness caused by very low doses of pathogens cannot generally be tested due to the numbers of subjects that would be needed, though such assessments of illness dose response are needed to evaluate drinking water standards. A predictive Bayesian dose-response assessment method was proposed previously to assess the unconditional probability of illness from available information and avoid the inconsistencies of confidence-based approaches. However, the method uses knowledge of the conditional dose-response form, and this form is not well established for the illness endpoint. A conditional parametric dose-response function for gastroenteric illness is proposed here based on simple numerical models of self-organized host-pathogen systems and probabilistic arguments. In the models, illnesses terminate when the host evolves by processes of natural selection to a self-organized critical value of wellness. A generalized beta-Poisson illness dose-response form emerges for the population as a whole. Use of this form is demonstrated in a predictive Bayesian dose-response assessment for cryptosporidiosis. Results suggest that a maximum allowable dose of 5.0 x 10(-7) oocysts/exposure (e.g., 2.5 x 10(-7) oocysts/L water) would correspond with the original goals of the U.S. Environmental Protection Agency Surface Water Treatment Rule, considering only primary illnesses resulting from Poisson-distributed pathogen counts. This estimate should be revised to account for non-Poisson distributions of Cryptosporidium parvum in drinking water and total response, considering secondary illness propagation in the population.     

短文听写在大班英语课堂中的运用

听写是英语教学中的一种有用的教学技巧,本文从短文听写在大班课堂上的具体运用表明：听写融合了听,写,说三方面的基本技能的结合且能有效解决英语大班英语教学中学生的听、说、写三方面的基本困难。     

考虑噪声因子的参数和公差经济性设计策略

基于并行工程思想的参数和公差经济性设计,以成本为优化目标来确定最优的设计参数和公差范围.就并行参数和公差设计通过双响应曲面均值和方差模型实现其稳健性,本文提出了包含噪声因子的响应曲面建模策略,应用这一模型将参数和公差同时优化.该参数和公差经济性设计优化模型以质量损失和制造成本之和为目标函数,以过程方差置信域为约束.实例结果表明,在双响应曲面方法中,对均值设置偏倚量比其刚性约束具有较大的成本优势,在不降低稳健性的前提下引入偏倚可以降低成本.面向噪声因子的设计策略其成本低于基于双响应的有偏倚的设计,说明考虑噪声因子的设计是最有效的.     

考虑脉冲现象的复杂供应链系统及其稳定策略

供应链系统是一个复杂的系统,一方面由于时间延迟、信息不对称及反馈机制等,会产生牛鞭效应,另一方面供应链具有需求突增或骤减的脉冲特点,上述现象都可能导致供应链系统混沌,而现有的供应链模型仅考虑了“牛鞭效应”,并未考虑脉冲现象对供应链系统的影响。文章建立了考虑脉冲现象的供应链模型,分析了脉冲现象对供应链系统的影响,并给出了使供应链系统稳定的策略,讨论了参数扰动对该模型的影响,通过数值算例验证了稳定策略的有效性。研究发现:脉冲现象对供应链系统有着显著影响,但只要选取恰当的脉冲强度和脉冲时间间隔,供应链系统是可以稳定的。     

上海股市流动性、收益率、交易量三者关系探讨

采用VAR(向量自回归)方法考察上海股票市场上流动性与收益率、交易量之间的关系。综合考虑理论计算结果和实证结果,可以作出判断:交易量和收益率导致流动性变动的因果关系显著,反之,因果关系并不显著。     

自然伽马能谱测井谱解析方法研究

自然伽马能谱测井是重要的核测井方法之一,其地面信息处理系统的关键是实测谱解析技术。低分辨率是自然伽马能谱测井仪的固有弱点,且测井过程中信噪比较低,造成测井置信度不高。从自然伽马能谱测井原理出发,通过中海油实验数据处理后获得的放射性核素的标准计数率谱,对自然伽马能谱测井4种传统数据处理方法的优劣进行了对比,初步探讨了将灵敏度高、空间分辨率好的直接解调方法移植到自然伽马能谱测井谱解析中,为自然伽马能谱测井谱解析方法的选择提供了依据。     

生活的多重可能性——浅析《黑王子》的召唤结构

英国小说家艾丽丝·默多克的代表作《黑王子》是一部具有实验性质的小说,从多个层面探讨了生活的本质,艺术与生活的关系。包括情节、引喻、叙事策略以及结构安排等构成了小说的召唤结构,共同作用于读者的阅读活动,使读者能够自觉地建构小说的意义,对其哲学内涵作出反应。     

Dose‐Response Models Incorporating Aerosol Size Dependency for Francisella tularensis

The effect of bioaerosol size was incorporated into predictive dose‐response models for the effects of inhaled aerosols of Francisella tularensis (the causative agent of tularemia) on rhesus monkeys and guinea pigs with bioaerosol diameters ranging between 1.0 and 24 μm. Aerosol‐size‐dependent models were formulated as modification of the exponential and β‐Poisson dose‐response models and model parameters were estimated using maximum likelihood methods and multiple data sets of quantal dose‐response data for which aerosol sizes of inhaled doses were known. Analysis of F. tularensis dose‐response data was best fit by an exponential dose‐response model with a power function including the particle diameter size substituting for the rate parameter k scaling the applied dose. There were differences in the pathogen's aerosol‐size‐dependence equation and models that better represent the observed dose‐response results than the estimate derived from applying the model developed by the International Commission on Radiological Protection (ICRP, 1994) that relies on differential regional lung deposition for human particle exposure.     

Treatment Choice With Trial Data: Statistical Decision Theory Should Supplant Hypothesis Testing

Abstract

A central objective of empirical research on treatment response is to inform treatment choice. Unfortunately, researchers commonly use concepts of statistical inference whose foundations are distant from the problem of treatment choice. It has been particularly common to use hypothesis tests to compare treatments. Wald’s development of statistical decision theory provides a coherent frequentist framework for use of sample data on treatment response to make treatment decisions. A body of recent research applies statistical decision theory to characterize uniformly satisfactory treatment choices, in the sense of maximum loss relative to optimal decisions (also known as maximum regret). This article describes the basic ideas and findings, which provide an appealing practical alternative to use of hypothesis tests. For simplicity, the article focuses on medical treatment with evidence from classical randomized clinical trials. The ideas apply generally, encompassing use of observational data and treatment choice in nonmedical contexts.     

Humanitarian response and stress in Kenya: gendered problems and their implications

ABSTRACT

Stress-related conditions such as burnout and post-traumatic stress disorder are a growing concern in the humanitarian sector. Aid workers themselves report not only that mental health problems are common, but that the support they receive from their employers is insufficient. Problematically, the experience of the international aid worker – particularly those who are white and from the global North – is often foregrounded in explaining what constitutes stress and related mental health problems. This indicates a wider problem of what is required of ‘the perfect humanitarian’ – a personality that is gendered and racialised – and how this influences the different experiences and treatment of national and international staff from aid agencies. This article explores the organisational culture and working conditions of humanitarian settings and their impact on the mental health and well-being of staff. It argues that there is a structural dimension to stress that is less to do with external security threats and more to do with the specific infrastructure, policies, and practices of humanitarian operations, with implications for aid workers which cut across dimensions of race, gender, and nationality.