Type I error rates from likelihood‐based repeated measures analyses of incomplete longitudinal data

The last observation carried forward (LOCF) approach is commonly utilized to handle missing values in the primary analysis of clinical trials. However, recent evidence suggests that likelihood‐based analyses developed under the missing at random (MAR) framework are sensible alternatives. The objective of this study was to assess the Type I error rates from a likelihood‐based MAR approach – mixed‐model repeated measures (MMRM) – compared with LOCF when estimating treatment contrasts for mean change from baseline to endpoint (Δ). Data emulating neuropsychiatric clinical trials were simulated in a 4 × 4 factorial arrangement of scenarios, using four patterns of mean changes over time and four strategies for deleting data to generate subject dropout via an MAR mechanism. In data with no dropout, estimates of Δ and SE_Δ from MMRM and LOCF were identical. In data with dropout, the Type I error rates (averaged across all scenarios) for MMRM and LOCF were 5.49% and 16.76%, respectively. In 11 of the 16 scenarios, the Type I error rate from MMRM was at least 1.00% closer to the expected rate of 5.00% than the corresponding rate from LOCF. In no scenario did LOCF yield a Type I error rate that was at least 1.00% closer to the expected rate than the corresponding rate from MMRM. The average estimate of SE_Δ from MMRM was greater in data with dropout than in complete data, whereas the average estimate of SE_Δ from LOCF was smaller in data with dropout than in complete data, suggesting that standard errors from MMRM better reflected the uncertainty in the data. The results from this investigation support those from previous studies, which found that MMRM provided reasonable control of Type I error even in the presence of MNAR missingness. No universally best approach to analysis of longitudinal data exists. However, likelihood‐based MAR approaches have been shown to perform well in a variety of situations and are a sensible alternative to the LOCF approach. MNAR methods can be used within a sensitivity analysis framework to test the potential presence and impact of MNAR data, thereby assessing robustness of results from an MAR method. Copyright © 2004 John Wiley & Sons, Ltd.     

蛋白组学方法应用于人肺癌组织蛋白表达的研究

采用蛋白组学方法,利用4例中国肺癌患者的切除肺癌组织测定了磷癌(SQCLC)的蛋白表达 从双向电泳(2-DEgel)切下53个点,49个蛋白与数据库搜索结果吻合。在鉴定的24个蛋白中,17个蛋白有报道是与肺癌相关的蛋白其7个蛋白与人类其它癌症相关。所建立的蛋白组学方法能够用于建立一种基于组织的化验方法,发现肺癌患者组织中表达的蛋白标记物以用于癌症的分子学诊断。     

山西省发展小杂粮的营销对策

小杂粮是山西省的特色农业产品,早以质量优、营养丰富而闻名全国。但就山西省而言,由于市场化、组织化程度较低,产品营销一直是钳制生产发展的瓶颈因素。因此,在发展小杂粮生产的问题上,我们首先要考虑的是;如何使小杂粮产品适应市场需求,顺利实现其价值。也就是先要有一个明确的营销思路,以避免生产决策的失误。只有选择适宜的目标市场、准确地进行市场定位、建立通畅的分销渠道等,才能促进小杂粮生产健康发展。     

Stjepan Metrović and Michel Maffesoli's 'implosive' defence of the Durkheimian tradition: theoretical convergences around Baudrillard's thesis on the 'end' of the social

This paper critically examines Metrovi? and Maffesoli's attempt to understand postmodernity through Émile Durkheim's nonrational link between society, religion and morality. Metrovi? (1991, 1997) and Maffesoli's (1996) work draws upon this emotional element when attempting to refute Baudrillard's (1983) cognitively focused, if implicit, critique of the Durkheimian tradition. Despite their best intentions, Metrovi? and Maffesoli still fail to exploit the partialities of Baudrillard's critique to the full. While both have some appreciation of the link between emotion and religion as found in Durkheim's The Elementary Forms of Religious Life (1912) they, nevertheless, fall short of grasping its full conceptual importance. This leads them to an implicit acceptance of Baudrillard's thesis on the ‘end’ of the social. This pitfall could have been avoided if Metrovi? and Maffesoli had built their respective analyses of the postmodern condition on a closer reading of The Elementary Forms. Reading this text alongside those other insights on emotion and social life as contained within Durkheim and Mauss's Primitive Classification (1903) and Talcott Parsons's subsequent writings on the sociological problem of religion, would have helped to distance the work of Metrovi? and Maffesoli from that of Baudrillard, and allowed them to offer a stronger and more comprehensive defence of the said tradition.     

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.     

欠发达地区经济发展研究

经济欠发达地区在我国土地面积中占有很大的比重,它的发展直接影响着国家经济发展的速度和综合国力的提高,千方百计促进欠发达地区的经济发展意义重大.然而,我国幅员辽阔,欠发达地区情况各异,如何发展这些地区是人们不断探索的重大课题.我们以自己的观点从某个侧面初步予以探索,以期与广大学者们共同探讨一些可行的发展途径,推动欠发达地区经济的繁荣.     

刍议当前农村女性剩余劳动力转化过程中的问题

农村女性剩余劳动力在农业向非农业转化过程中，出现了年龄低龄化趋向、文化程度以初中文化为主、专门技术的掌握程度低、劳动权益保护状况堪忧等状况。针对上述现象，国家应通过法律、政策的制定，对处于就业弱势的农村女性予以更多的考虑、照顾；通过增加农村女性受教育的机会和建立具有性别倾斜的就业培训和就业指导体系，增加农村女性就业机会。     

Implied Preference for Seismic Design Level and Earthquake Insurance

Seismic risk can be reduced by implementing newly developed seismic provisions in design codes. Furthermore, financial protection or enhanced utility and happiness for stakeholders could be gained through the purchase of earthquake insurance. If this is not so, there would be no market for such insurance. However, perceived benefit associated with insurance is not universally shared by stakeholders partly due to their diverse risk attitudes. This study investigates the implied seismic design preference with insurance options for decisionmakers of bounded rationality whose preferences could be adequately represented by the cumulative prospect theory (CPT). The investigation is focused on assessing the sensitivity of the implied seismic design preference with insurance options to model parameters of the CPT and to fair and unfair insurance arrangements. Numerical results suggest that human cognitive limitation and risk perception can affect the implied seismic design preference by the CPT significantly. The mandatory purchase of fair insurance will lead the implied seismic design preference to the optimum design level that is dictated by the minimum expected lifecycle cost rule. Unfair insurance decreases the expected gain as well as its associated variability, which is preferred by risk-averse decisionmakers. The obtained results of the implied preference for the combination of the seismic design level and insurance option suggest that property owners, financial institutions, and municipalities can take advantage of affordable insurance to establish successful seismic risk management strategies.     

中国农村妇女问题研究综述

随着党中央对三农问题的重视,中国农村妇女问题逐渐凸现出来。对近二十年的中国农村妇女研究重新进行阶段划分,并对中国农村妇女研究所涉及的性别与劳动就业分工,农业女性化问题,农村妇女家庭地位及其变化,农村妇女科学文化素质及培训,农村女性劳动力流动及影响因素,农村妇女与贫困,农村妇女与人口再生产,农村妇女与资源、环境和持续发展,农村妇女参政议政等问题,进行多角度的分析说明,从中总结出经验和不足。农村妇女发展要联系农村实际,要针对多方面因素考虑农村妇女发展与农村诸要素之间的关系。农村妇女研究要采取定量与定性相结合的分析方法,从不同地域、不同环境入手分析当地农村妇女的实际情况,以便在今后的研究中得以借鉴。