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21.
The aim of this study was to develop a modified quantitative microbial risk assessment (QMRA) framework that could be applied as a decision support tool to choose between alternative drinking water interventions in the developing context. The impact of different household water treatment (HWT) interventions on the overall incidence of diarrheal disease and disability adjusted life years (DALYs) was estimated, without relying on source water pathogen concentration as the starting point for the analysis. A framework was developed and a software tool constructed and then implemented for an illustrative case study for Nepal based on published scientific data. Coagulation combined with free chlorine disinfection provided the greatest estimated health gains in the short term; however, when long‐term compliance was incorporated into the calculations, the preferred intervention was porous ceramic filtration. The model demonstrates how the QMRA framework can be used to integrate evidence from different studies to inform management decisions, and in particular to prioritize the next best intervention with respect to estimated reduction in diarrheal incidence. This study only considered HWT interventions; it is recognized that a systematic consideration of sanitation, recreation, and drinking water pathways is important for effective management of waterborne transmission of pathogens, and the approach could be expanded to consider the broader water‐related context.  相似文献   
22.
The primary objective of a multi-regional clinical trial is to investigate the overall efficacy of the drug across regions and evaluate the possibility of applying the overall trial result to some specific region. A challenge arises when there is not enough regional sample size. We focus on the problem of evaluating applicability of a drug to a specific region of interest under the criterion of preserving a certain proportion of the overall treatment effect in the region. We propose a variant of James-Stein shrinkage estimator in the empirical Bayes context for the region-specific treatment effect. The estimator has the features of accommodating the between-region variation and finiteness correction of bias. We also propose a truncated version of the proposed shrinkage estimator to further protect risk in the presence of extreme value of regional treatment effect. Based on the proposed estimator, we provide the consistency assessment criterion and sample size calculation for the region of interest. Simulations are conducted to demonstrate the performance of the proposed estimators in comparison with some existing methods. A hypothetical example is presented to illustrate the application of the proposed method.  相似文献   
23.
随着网络视频运营商收费节目试看的兴起,而节目试看对网络视频运营商诸如市场规模,利润等市场策略的影响所知甚少。本文在考虑网络用户情绪效用情况下,通过构建高质量视频运营商首播节目与后来跟进的低质量视频运营商播出该节目的博弈模型,研究高质量视频运营商首播节目之前提供节目试看对两个运营商收费模式下的节目最优收费价格和免费模式下的最优嵌入广告量以及视频节目提供模式选择的影响。研究表明,高质量视频运营商在节目首播之前提供节目充分试看能够实现节目最优收费价格最高,利润最大,因此节目充分试看是其最优策略;并且低质量运营商在其单位广告收益与用户单位广告"成本"满足一定条件下,高质量运营商提供的节目的充分试看能够减少低质量运营商总利润,因此避免低质量视频运营商搭乘节目试看的顺风车;高质量视频运营商提供节目充分试看情况下,高质量视频运营商只采取收费模式为其最优市场策略,低质量视频运营商采取免费模式为其最优市场策略。本文的研究成果对网络视频运营商日常运营有一定的管理学启示与应用价值。  相似文献   
24.
In recent years, seamless phase I/II clinical trials have drawn much attention, as they consider both toxicity and efficacy endpoints in finding an optimal dose (OD). Engaging an appropriate number of patients in a trial is a challenging task. This paper attempts a dynamic stopping rule to save resources in phase I/II trials. That is, the stopping rule aims to save patients from unnecessary toxic or subtherapeutic doses. We allow a trial to stop early when widths of the confidence intervals for the dose-response parameters become narrower or when the sample size is equal to a predefined size, whichever comes first. The simulation study of dose-response scenarios in various settings demonstrates that the proposed stopping rule can engage an appropriate number of patients. Therefore, we suggest its use in clinical trials.  相似文献   
25.
针对农民社会阶层与幸福感问题,通过分析2010-2015年“中国综合社会调查”数据,采用有序响应Logit模型估计,实证检验了农民社会阶层定位的幸福效应。研究发现,农民社会阶层定位存在幸福效应,社会阶层定位越高的农民,其幸福感越强;进一步区域比较发现,此幸福效应在经济发达地区最为显著;而户籍比较发现,农民社会阶层定位的幸福效应低于城镇居民;但从发展趋势来看,农民社会阶层定位的幸福效应较10年前有所增强,且农民对社会阶层定位有较为乐观的预期。据此提出,民生建设中重视农民的发展诉求和精神需求,融通农民社会阶层上升的渠道,从而提高农民幸福感,保障农民公平共享社会发展的成果。  相似文献   
26.
我国宪法赋予了公民用自己的民族语言文字参加诉讼的权利,目的在于实现民族平等、促进民族团结、禁止民族分裂、保护中华民族语言文化的多样性,进而提高我国的文化软实力。通过调查民族语言文字诉讼司法实务,发现当前存在着少数民族语言文字诉讼程序混乱、不符合诉讼原理等问题,不利于民族语言文字诉讼权利的实现。究其原因,在于该诉讼制度缺乏程序保障。为了确保民族语言文字诉讼权利的有效实现,应设立“民汉双语诉讼规则”,以为司法机关提供统一的操作规范。民汉双语诉讼规则应该明确民汉双语诉讼的概念、类型以及民族语言文字诉讼权利的内容,并且根据不同诉讼类型有针对性地设置审判语言与诉讼语言的适用规则。  相似文献   
27.
Clinical phase II trials in oncology are conducted to determine whether the activity of a new anticancer treatment is promising enough to merit further investigation. Two‐stage designs are commonly used for this situation to allow for early termination. Designs proposed in the literature so far have the common drawback that the sample sizes for the two stages have to be specified in the protocol and have to be adhered to strictly during the course of the trial. As a consequence, designs that allow a higher extent of flexibility are desirable. In this article, we propose a new adaptive method that allows an arbitrary modification of the sample size of the second stage using the results of the interim analysis or external information while controlling the type I error rate. If the sample size is not changed during the trial, the proposed design shows very similar characteristics to the optimal two‐stage design proposed by Chang et al. (Biometrics 1987; 43:865–874). However, the new design allows the use of mid‐course information for the planning of the second stage, thus meeting practical requirements when performing clinical phase II trials in oncology. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
28.
能够对现代社会产生长远影响的本源型传统,构成现代社会发展的基础性制度。在东方国家的本源型传统中,不同于俄国和印度的村社制,中国是家户制,并在此基础上形成独特的中国农村发展道路。其中包括:以家户经营为基础的农业经营组织,家户内部农工商结合基础上的农工商互补经济,家户互助合作基础上的农村合作形式,家国共治基础上的农村治理体系。在中国农村发展进程中,尽管家户制一度被抛弃,但仍构成当下及未来农村发展的制度底色。  相似文献   
29.
In many clinical trials, biological, pharmacological, or clinical information is used to define candidate subgroups of patients that might have a differential treatment effect. Once the trial results are available, interest will focus on subgroups with an increased treatment effect. Estimating a treatment effect for these groups, together with an adequate uncertainty statement is challenging, owing to the resulting “random high” / selection bias. In this paper, we will investigate Bayesian model averaging to address this problem. The general motivation for the use of model averaging is to realize that subgroup selection can be viewed as model selection, so that methods to deal with model selection uncertainty, such as model averaging, can be used also in this setting. Simulations are used to evaluate the performance of the proposed approach. We illustrate it on an example early‐phase clinical trial.  相似文献   
30.
In this article, I explore the intricate relationship between regulation and contingency in processes of urban economic organisation by focusing on the workings of a central bus station in Accra, Ghana. After introducing the position of the station in Ghana’s urban economy and transport infrastructure, I set out its internal regulative arrangements in relation to larger socio-economic and political constellations the practices of the station workers are contingent upon. Next, I turn the analysis around and describe the ways in which people accommodate themselves within, exploit and thereby co-produce emergent contingencies. The focus on the station, I suggest, offers a window into the complex constituents of niche economic practices that prevail in many spheres of African cities and allows a nuanced reflection on the incongruous and undetermined dynamics of everyday urban ‘becomings.’  相似文献   
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