Methods improving the estimate of diagnostic odds ratio

Diagnostic odds ratio is defined as the ratio of the odds of the positivity of a diagnostic test results in the diseased population relative to that in the non-diseased population. It is a function of sensitivity and specificity, which can be seen as an indicator of the diagnostic accuracy for the evaluation of a biomarker/test. The naïve estimator of diagnostic odds ratio fails when either sensitivity or specificity is close to one, which leads the denominator of diagnostic odds ratio equal to zero. We propose several methods to adjust for such situation. Agresti and Coull’s adjustment is a common and straightforward way for extreme binomial proportions. Alternatively, estimation methods based on a more advanced sampling design can be applied, which systematically selects samples from underlying population based on judgment ranks. Under such design, the odds can be estimated by the sum of indicator functions and thus avoid the situation of dividing by zero and provide a valid estimation. The asymptotic mean and variance of the proposed estimators are derived. All methods are readily applied for the confidence interval estimation and hypothesis testing for diagnostic odds ratio. A simulation study is conducted to compare the efficiency of the proposed methods. Finally, the proposed methods are illustrated using a real dataset.     

海盗罪的国际法规制

为了打击海盗行为，16世纪以后，西方各国逐渐形成了关于海盗罪的国际习惯法体系。进入20世纪，国际社会开始致力于将惩治海盗的习惯法法典化。《尼翁协定》及《尼翁补充协定》是前期的主要成果。二战结束后，国际社会制定了《日内瓦公海公约》和《联合国海洋法公约》，对海盗罪的定义、构成要件及执法权限等作出了明确规定。上世纪80年代后，国际海事组织又制定了《制止危及海上航行安全非法行为公约》、《关于海盗和海上暴力行为的示范国内法》等富于操作性的法律文件。     

Modified Wilcoxon–Mann–Whitney Test and Power Against Strong Null

The Wilcoxon–Mann–Whitney (WMW) test is a popular rank-based two-sample testing procedure for the strong null hypothesis that the two samples come from the same distribution. A modified WMW test, the Fligner–Policello (FP) test, has been proposed for comparing the medians of two populations. A fact that may be under-appreciated among some practitioners is that the FP test can also be used to test the strong null like the WMW. In this article, we compare the power of the WMW and FP tests for testing the strong null. Our results show that neither test is uniformly better than the other and that there can be substantial differences in power between the two choices. We propose a new, modified WMW test that combines the WMW and FP tests. Monte Carlo studies show that the combined test has good power compared to either the WMW and FP test. We provide a fast implementation of the proposed test in an open-source software. Supplementary materials for this article are available online.     

塔式太阳能热发电中冷回热再热燃气轮机循环研究——功率与效率

用热力学方法研究了塔式太阳能热发电中冷回热再热三级不可逆闭式燃气轮机循环的功率和效率.通过数值分析方法,计算了中冷度、回热度对循环最优功率、最优效率及其中间压比分配的关系.与闭式中冷回热燃气轮机循环的功率和效率比较,最大平均功率、最优功率和最优功率效率都有很大的提高.     

科技与文化融合促产业文化化

提高广州制造业的文化元素和科技元素的含量,加强文化创意产业与制造业的融合,不仅是提升广州产业竞争力的良方,也是提升广州整体经济竞争力切实可行的举措.     

Status of an alien turtle in city park waters and its potential threats to local biodiversity: the red-eared slider in Beijing

Urban Ecosystems - Invasive alien species pose a serious threat to native biodiversity and the ecosystem structure through predation or competition, and this threat is especially severe in China....     

发挥统一战线的本质功能

新时期党的统一战线的本质,是坚持大团结、大联合,最广泛、最充分地调动一切积极因素,团结一切可以团结的力量,为实现党和国家的宏伟目标而奋斗。本文从坚持马克思主义人本观、民本观、劳动观、财富观、人才观等新的视域,深入阐述了如何发挥统一战线的凝聚共识、团结爱国、整合力量、创造财富、聚集人才等强大功能。     

“Hmoob”“Mab”及“Suav”:美国苗族“Hmoob”人的自我认同与族群分野

美国苗族“Hmoob”人,仍然保存着自己的语言. “Hmoob”人的语言属于苗语西部方言的一种次方言,其中某些词汇可能源于古代汉语.“Hmoob”人现今仍然在使用的几个词汇如“Hmoob”“Mab”和“Suav”能够清晰地反映出“Hmoob”人群体的自我认同与族群分野建构的历史过程.在建构自我认同与族群分野系统的过程中, “Hmoob”人的族际关系观念受到其历史迁徙过程与华夏民族观的影响,但文化自觉因素在其中扮演着主要的角色. “Mab”一词与其衍生词汇在美国“Hmoob”人群体的当代自我认同与族际分野中仍然存在,但已在一定程度上发生了变化.     

高校校园选址与资源共享研究——以广州大学城为例

通过对广州大学城高校之间的横向对比,以及各高校新老校区的对比研究,分析高校校园选址对学生学习和生活的影响,及多个校区对高校师生相互之间交流的影响。调查大学城高校校际交流与资源共享满意度评价,得出大学城共享性实施效果一般,并分析其优点及缺陷。