A Bayesian Adjustment for Covariate Misclassification with Correlated Binary Outcome Data

Estimated associations between an outcome variable and misclassified covariates tend to be biased when the methods of estimation that ignore the classification error are applied. Available methods to account for misclassification often require the use of a validation sample (i.e. a gold standard). In practice, however, such a gold standard may be unavailable or impractical. We propose a Bayesian approach to adjust for misclassification in a binary covariate in the random effect logistic model when a gold standard is not available. This Markov Chain Monte Carlo (MCMC) approach uses two imperfect measures of a dichotomous exposure under the assumptions of conditional independence and non-differential misclassification. A simulated numerical example and a real clinical example are given to illustrate the proposed approach. Our results suggest that the estimated log odds of inpatient care and the corresponding standard deviation are much larger in our proposed method compared with the models ignoring misclassification. Ignoring misclassification produces downwardly biased estimates and underestimate uncertainty.     

构建沈阳自主创新科技投融资体系的途径选择

建立创新型城市离不开多元化、多渠道、多层次的科技投融资体系。通过有效的政策安排,不断完善科技投融资体系,对加快沈阳的发展,加速科技创新进程和科技成果转化具有重要意义。本文提出了沈阳自主创新亟待投融资体系的完善,着重分析了沈阳自主创新科技投融资体系的现状和存在的问题,提出了促进沈阳自主创新科技投融资体系完善的途径。     

城市化进程中土地利用之误区及其出路

土地利用是否合乎城市化进程的客观规律与内在要求，将直接决定城市化成就与否。我国可供利用的土地资源相对缺乏。土地的法律属性为公有制所有制，土地所有权不得转让，但土地使用权可以合法转让。在我国城市化进程中，土地利用存在着城市化等同于城市规模和功能的大而全、城市化等同于农村城市化（城镇化）和农民市民化、征收农业用地是城市化所需土地的唯一来源、城市规模的扩大有利于经济的发展和社会利益最大化等认识误区。我们应在参考借鉴国外相应制度的基础上，采取在条件适合地区推进农地的规模利用；科学规划，严格监控，建立有中国特色的集约用地制度：完善土地的市场定价机制，丰富土地取得方式，实现土地资源的市场化配置等措施，科学利用土地，合理推进城市化进程。     

Examples of the use of an equivalence theorem in constructing optimum experimental designs for random-effects nonlinear regression models

The problem considered is that of finding an optimum measurement schedule to estimate population parameters in a nonlinear model when the patient effects are random. The paper presents examples of the use of sensitivity functions, derived from the General Equivalence Theorem for D-optimality, in the construction of optimum population designs for such schedules. With independent observations, the theorem applies to the potential inclusion of a single observation. However, in population designs the observations are correlated and the theorem applies to the inclusion of an additional measurement schedule. In one example, three groups of patients of differing size are subject to distinct schedules. Numerical, as opposed to analytical, calculation of the sensitivity function is advocated. The required covariances of the observations are found by simulation.     

Non-ignorable missing covariate data in survival analysis: a case-study of an International Breast Cancer Study Group trial

Summary.  Non-ignorable missing data, a serious problem in both clinical trials and observational studies, can lead to biased inferences. Quality-of-life measures have become increasingly popular in clinical trials. However, these measures are often incompletely observed, and investigators may suspect that missing quality-of-life data are likely to be non-ignorable. Although several recent references have addressed missing covariates in survival analysis, they all required the assumption that missingness is at random or that all covariates are discrete. We present a method for estimating the parameters in the Cox proportional hazards model when missing covariates may be non-ignorable and continuous or discrete. Our method is useful in reducing the bias and improving efficiency in the presence of missing data. The methodology clearly specifies assumptions about the missing data mechanism and, through sensitivity analysis, helps investigators to understand the potential effect of missing data on study results.     

Statistical and Combinatorial Aspects of Comparative Genomics*

Abstract. This document presents a survey of the statistical and combinatorial aspects of four areas of comparative genomics: gene order based measures of evolutionary distances between species, construction of phylogenetic trees, detection of horizontal transfer of genes, and detection of ancient whole genome duplications.     

On Optimality of Bayesian Wavelet Estimators

Abstract.  We investigate the asymptotic optimality of several Bayesian wavelet estimators, namely, posterior mean, posterior median and Bayes Factor, where the prior imposed on wavelet coefficients is a mixture of a mass function at zero and a Gaussian density. We show that in terms of the mean squared error, for the properly chosen hyperparameters of the prior, all the three resulting Bayesian wavelet estimators achieve optimal minimax rates within any prescribed Besov space     for p  ≥ 2. For 1 ≤  p  < 2, the Bayes Factor is still optimal for (2 s +2)/(2 s +1) ≤  p  < 2 and always outperforms the posterior mean and the posterior median that can achieve only the best possible rates for linear estimators in this case.     

Assessing goodness-of-fit of categorical regression models based on case-control data

Demonstrated equivalence between a categorical regression model based on case‐control data and an I‐sample semiparametric selection bias model leads to a new goodness‐of‐fit test. The proposed test statistic is an extension of an existing Kolmogorov–Smirnov‐type statistic and is the weighted average of the absolute differences between two estimated distribution functions in each response category. The paper establishes an optimal property for the maximum semiparametric likelihood estimator of the parameters in the I‐sample semiparametric selection bias model. It also presents a bootstrap procedure, some simulation results and an analysis of two real datasets.     

谭献词学理论的继承与创新

谭献是晚清一位词学大家 ,在继承常州派张惠言、周济词学理论的基础上 ,根据自己创作和整理词集的经验和心得 ,提出了新的词学观点 ,进一步完善了常州派词论 ,对中国词学理论有杰出的贡献。谭献的词论主要有 :一、继承常州词派的观点 ,继续推尊词体。二、在词的创作方面 ,提倡比兴柔厚。三、在词的鉴赏批评上 ,提出“作者之用心未必然 ,读者之用心何必不然”的著名观点。     

提高我国文化软实力的意义与对策

文化软实力是综合国力和国际竞争力的重要组成部分,我国要在激烈的国际竞争中赢得主动,就必须使国家文化软实力有一个大的提高。为此,要构建社会主义核心价值体系,努力提高国民综合素质;加强文化交流与传播,提高中华文化的渗透力;推进文化创新和文化体制改革,充分发掘中华传统文化的优势;在公共文化服务体系建设中,加强基层文化建设,以城市社区文化建设和农村文化建设为落点;建立产品丰富、门类齐全、结构合理、运行规范的文化市场体系,运用高新技术创新文化生产方式,培育新的文化业态,加快构建传输快捷、覆盖广泛的文化传播体系。