Separation of individual-level and cluster-level covariate effects in regression analysis of correlated data

The focus of this paper is regression analysis of clustered data. Although the presence of intracluster correlation (the tendency for items within a cluster to respond alike) is typically viewed as an obstacle to good inference, the complex structure of clustered data offers significant analytic advantages over independent data. One key advantage is the ability to separate effects at the individual (or item-specific) level and the group (or cluster-specific) level. We review different approaches for the separation of individual-level and cluster-level effects on response, their appropriate interpretation and give recommendations for model fitting based on the intent of the data analyst. Unlike many earlier papers on this topic, we place particular emphasis on the interpretation of the cluster-level covariate effect. The main ideas of the paper are highlighted in an analysis of the relationship between birth weight and IQ using sibling data from a large birth cohort study.     

A modeling framework for the analysis of HPV incidence and persistence: A semi‐parametric approach for clustered binary longitudinal data analysis

Human papillomavirus (HPV) infection is a common sexually transmitted disease of growing public health importance, and over 40 genotypes have been identified in genital infections. Current HPV cohort studies often follow participants at pre‐determined visits, such as every 6 months, and data generated from such epidemiology studies can be described as clustered longitudinal binary data where correlation arises in two ways: the directionless clustering due to the multiple genotypes tested within an individual, and the temporal correlation among the repeated measurements on the same genotype along time. Current analyses for identification of risk factors associated with HPV incidence and persistence often either do not fully utilize information in the data set or ignore the correlation between the multiple genotypes. Given the scientific definition of incidence and persistence, conditional probability modeling provides us a natural mathematical tool. We thus present a semi‐parametric regression model for such data where full specification of the joint multivariate binary distribution is avoided by using conditioning argument to handle the temporal correlation and GEE to account for the correlation between the multiple genotypes. The model is applied to the HPV data from the Rakai male circumcision (MC) trial to evaluate the as‐treated efficacy of MC and also identify modifiable risk factors for incidence and persistence of oncogenic HPV types in men. A simulation study is performed to provide empirical information on the number of individuals that is needed for satisfactory power and estimation accuracy of the association parameter estimates in future studies. Copyright © 2010 John Wiley & Sons, Ltd.     

竹笋提取液复合制剂在失血性贫血中的疗效观察

目的观察竹笋提取液复合制剂治疗失血性贫血的疗效。方法分别采用医用生化分析仪、HP1100色谱仪以及ICTMS检测竹笋提取液中葡萄糖、总蛋白、宏量元素,氨基酸和微量元素的含量。以小鼠内眦静脉丛取血法,建立失血性贫血小鼠动物模型;采用灌胃给药的方式,2个实验组(药物组)分别给予竹笋提取液复合铁制剂1(0.15%铁卟啉、10%蜂蜜)、制剂2(70%竹笋提取液、0.15%铁卟啉、10%蜂蜜),1个对照组给予同等剂量去离子水,于给药的不同时间点0、18、42、67和90 h从小鼠尾静脉取血,测定血红蛋白(Hb)、红细胞(RBC)、红细胞压积(Hct)。急性毒性试验采用小鼠最大灌胃量给药,观察有无毒性反应。结果制剂2中的竹笋提取液中含有葡萄糖,蛋白质,Na、Cl、Mg、K、Ca、P等多种宏量元素,刺激或参与造血功能的Mn、Fe、Zn、Cu等微量元素,以及促进非血红素铁吸收的多种氨基酸成分;小鼠失血后立刻给药,制剂1与制剂2对失血性贫血的疗效均好于对照组,且制剂2优于制剂1(P<0.05);急性经口毒性动物实验未见异常。结论竹笋提取液含有丰富的葡萄糖、蛋白质以及多种元素,能够刺激造血,扩充血容量,其复合铁制剂对失血性贫血的恢复有促进作用。     

集束化培训模式对护士心肺复苏培训质量的影响

目的 探讨集束化培训模式对护士心肺复苏质量的影响.方法 将2019年2月 2020年2月于佛山市中医院进行轮科实习的护士100名,按照随机数字表法分为对照组和观察组,每组50名.对照组采取传统教学模式进行心肺复苏培训,观察组采取集束化培训模式进行心肺复苏培训.比较2组培训前后按压深度、按压频率、胸廓回弹率,比较2组发现...     

甘肃省中药南沙参资源调查

甘肃省中药南沙参资源调查周印锁,丁义兰,徐涛(兰州医学院药学系生药学教研室730000)StudiesonCultringtheEmbryoofTripterygiumhypoglaucum(Level.)Hutch.inVitro$GuoXiaohong(ExperimentalCentreofKunmingMedicalCollege650031)YangMaoxian(BiologyDepartmentofYunnanUniversity,Kunming650033)ThispaperforthetimereportsfirsttheembryoculturinginvitroofTripterygiumhypoglaucum.TestswereconductedOfeveryconditionforthe...     

Design of a clustered observational study to predict emergency admissions in the elderly: statistical reasoning in clinical practice

OBJECTIVE: To describe the statistical design issues and practical considerations that had to be addressed in setting up a clustered observational study of emergency admission to hospital of elderly people. STUDY DESIGN AND SETTING: Clustered observational study (sample survey) of elderly people registered with 18 general practices in Halton Primary Care Trust in the north-west of England. RESULTS: The statistical design features that warranted particular attention were sample size determination, intra-class correlation, sampling and recruitment, bias and confounding. Pragmatic decisions based on derived scenarios of different design effects are discussed. A pilot study was carried out in one practice. From the remaining practices, a total of 4000 people were sampled, stratified by gender. The average cluster size was 200 and the intra-class correlation coefficient for the emergency admission outcome was 0.00034, 95% confidence interval (0-0.008). CONCLUSION: Studies that involve sampling from clusters of people are common in a wide range of healthcare settings. The clustering adds an extra level of complexity to the study design. This study provides an empirical illustration of the importance of statistical as well as clinical reasoning in study design in clinical practice.     

郑州市新型冠状病毒肺炎聚集性疫情分析

目的分析郑州市新型冠状病毒肺炎聚集性疫情的流行特征,为制定有效防控措施提供依据。方法采用流行病学描述方法对聚集性疫情资料进行整理分析。结果2020年1月21日-2020年2月20日郑州市共34起新型冠状病毒肺炎聚集性疫情,其中家庭(族)聚集占85.29%(29/34),国际旅行聚集占5.88%(2/34),公司聚集占2.94%(1/34),医院聚集占5.88%(2/34);聚集性疫情涉及确诊病例人数占郑州市报告确诊病例的61.15%(96/157);发病原因与外省外市相关(包括武汉)的聚集性疫情占58.82%;1起聚集疫情中,续发病例中1例早于指示病例发病,1例与指示病例同时发病。结论郑州市聚集性疫情以家庭(族)聚集为主,病例密切接触者一律实行集中隔离医学观察是有必要的。在复工复产之后,应落实好各项相关政策,警惕企事业单位聚集性疫情的发生。续发病例早于或者与指示病例同时发病,提示潜伏期具有传染性的风险。     

Effects of Cholera Toxin on Small Intestinal Motor Activity in the Fasted State

We sought to determine the effect of cholera toxin on small intestinal motor activity in the fasted state and relate it to secretion in conscious dogs. Motor activity was recorded by strain gauge force transducers and secretion was measured by diverting it to the outside through a two-way cannula. Inoculation of the study segment with cholera toxin resulted in a 10-fold increase in fluid output by 120 minutes postinjection. At the same time that fluid output increased Significantly changes in fasting motor activity occurred. The cycle length of the migrating motor complex was significantly reduced, the percentage of phase II activity was significantly increased, and migrating clustered contractions were inhibited. Perfusion of the study segment by a nonabsorbable electrolyte solution at a rate similar to the rate of secretion induced by cholera toxin did not change the cycle length of migrating motor complexes, but the percentage of phase II activity was significantly increased as with cholera toxin, and migrating clustered contractions were inhibited. The reduction in the cycle length of migrating motor complexes seems to be a direct effect of cholera toxin on the gut wall while the increase in percentage of phase II activity and inhibition of migrating clustered contractions appear to be indirect effects due to fluid accumulation.     

富硒蒜苗的培植及其中硒对其它微量元素的影响

<正> 本文以含硒较多的大蒜作为研究对象,通过培养,观察加硒对蒜苗生长的影响以及硒在蒜苗中富集的情况,并通过测定,研究硒与其它微量元素间的关系。材料仪器和试剂一、主要材料和仪器大蒜头:产地——山东历城 JP——2型示波极谱仪三电极系统日立189—80型塞曼原子吸收分光光度计紫外低温消化仪