Difference of two dependent sensitivities and specificities: Comparison of various approaches

In diagnostic studies, a new diagnostic test is often compared with a standard test and both tests are applied on the same patients, called paired design. The true disease state is in general given by the so‐called gold standard (most reliable method for classification), which has to be known for all patients. The benefit of the new diagnostic test can be evaluated by sensitivity and specificity, which are in fact proportions. This means, for the comparison of two diagnostic tests, confidence intervals for the difference of the dependent estimated sensitivities and specificities are calculated. In the literature, many comparisons of different approaches can be found, but none explicitly for diagnostic studies. For this reason we compare 13 approaches for a set of scenarios that represent data of diagnostic studies (e.g., with sensitivity and specificity ?0.8). With simulation studies, we show that the nonparametric interval with normal approximation can be recommended for the difference of two dependent sensitivities or specificities without restriction, the Wald interval with the limitation of slightly anti‐conservative results for small sample sizes, and the nonparametric intervals with t‐approximation, and the Tango interval with the limitation of conservative results for high correlations.     

关于健康成人左右运动神经传导参数的比较

目的:研究正常人左、右侧的末梢神经传导特点及易损伤性,探讨生活习惯与末梢神经潜在性损伤的内在关联,提高电生理诊断准确率。方法:100名志愿者为对象,检测正中、尺、胫和腓神经的复合肌肉动作电位(CMAP)、F波,观察左、右侧的神经传导参数及左右差值与生活习惯之间的联系。结果:左侧尺、胫运动神经传导速度(MCV)慢于右侧(P值各为0.013、0.011)。MCV≤X-1S尺神经组的远端潜伏期(D Lat)、F波最短潜伏期(F-Lat)延长于MCV>X-1S组(P值均为0.000)。MCV≤X-1S胫神经组的近端波幅(P Amp)低于MCV>X-1S组(P=0.000)。右侧腓神经D Lat延长于左侧(P=0.007),D Lat≥X+1S腓神经组的MCV、F-Lat平均值慢或延长于D Lat相似文献   

Comparative Insect Faunas between Ganghwado and Six others Islands of West Coastal in Incheon,Korea

This paper is intended as an investigation of the biogeographic characteristics of insect faunas of the seven islands in West Coastal of Incheon, Korea, using quantitative analysis. The faunal similarity is examined using the Bray & Curtis similarity. The obtained similarity value matrix was examined by a cluster analysis using UPGMA method. The number and the distribution records of each species in the areas are 1,001 species of insects belonging to 12 orders from the seven investigated islands. Among above seven islands, Seokmodo has the highest number of species, 497 species, while Yeonpyeongdo has the lowest, 136 species. The species composition of insects reported in Ganghwado was 309 species under seven orders. The similarity values between seven localities investigated range from 24.907(Gyodongdo to Yeonpyeongdo) to 49.899(Baengnyeongdo to Ganghwado). That is, the species composition of Baengnyeongdo(47.90%) was similar to that of Ganghwado, while that of Yeonpyeongdo(25.28%) was different from that. The cluster analysis using a similarity index shows that all the islands of these areas can be divided into 3 groups at the level of 30.97%.     

尺神经原位松解术与尺神经皮下前置术治疗肘管综合征近期疗效比较的回顾性研究

目的:比较尺神经原位松解术与尺神经皮下前置术治疗肘管综合征(CuTS)近期疗效。方法:本研究为回顾性研究,选取2016年7月～2017年7月期间我院二部收治的60例CuTS患者,根据手术方式的不同分为A组(n=32,尺神经原位松解术)和B组(n=28,尺神经皮下前置术),比较两组患者优良率、并发症、围术期指标、感觉运动功能(肌力、小指指端两点辨别觉、神经传导速度)以及DASH上肢功能障碍(DASH)评分。结果:B组术后12个月的优良率为92.86%(26/28),高于A组的68.75%(22/32)(P0.05)。两组术后并发症总发生率比较差异无统计学意义(P0.05)。两组术后12个月肌力、神经传导速度升高,且B组高于A组(P0.05),两组术后12个月小指指端两点辨别觉降低,且B组低于A组(P0.05)。两组术后3个月、术后6个月、术后12个月DASH评分呈下降趋势,且B组低于A组(P0.05)。B组手术切口长度、手术时间长于A组(P0.05),两组术后住院时间比较差异无统计学意义(P0.05)。结论:与尺神经原位松解术相比,尺神经皮下前置术治疗CuTS患者,虽然手术切口长度、手术时间相对较长,但其优良率更高,同时可有效恢复患者感觉运动功能及减轻其上肢功能障碍,且不增加并发症发生率,具有一定的临床应用价值。     

获取全长cDNA若干方法的比较

生物技术突飞猛进大大提高了人类认识自身及与人类息息相关的生命现象的能力。近几年内 ,人类 [1,2 ]、模式生物拟南芥 ( Arabidopsis thaliana) [3 5]及水稻的基因组测序 [6,7]的草图相继完成 ,给人类又提出了新的挑战 :如何鉴定这些序列的功能及如何解析生命现象的基因本质 ,这是一个更加庞大而又极富挑战性的课题 ,正促使一门新的学科即功能基因组学 ( Functional genomics)的产生与蓬勃发展。不论功能基因组学多么深奥 ,其认识基因功能的基本前提是获取可能有相关功能的基因之全长编码序列。其中 ,全长 c DNA序列的获取是正确地注释基…     

哀牢山国家级自然保护区南华片三种雉类春季取食地利用比较

探讨亲缘关系密切、营养关系相似的物种间的共存机制,是群落生态学的研究热点之一。研究结果有助于了解同域物种的资源利用特点和分化方式,对于地区生物多样性的保育工作亦具有指导意义。黑颈长尾雉(Syrmaticushumiae)、白鹇(Lophuranycthemera)和红喉山鹧鸪(Arborophilarufogularis)为哀牢山国家自然保护区南华片区同域分布的3种雉类,它们亲缘关系较近,食性相似。比较三者春季取食地18个生态因子生态位宽度和重叠指数,结果显示,黑颈长尾雉广适性(生态位宽度值>0·8)的取食地因子最少(1个),专一性(生态位宽度<0·8)因子最多(4个);白鹇居中(3个和2个);红喉山鹧鸪与黑颈长尾雉恰好相反(6个和0个)。黑颈长尾雉与白鹇生态位重叠指数≥0·5的因子数(5个)多于黑颈长尾雉与红喉山鹧鸪的(2个)和白鹇与红喉山鹧鸪的(4个);灌木层盖度、草本层盖度和种子密度的生态位重叠指数在3种雉类间均较大。单因素方差分析结果表明,3种雉类在坡向、乔木密度、草本层盖度、种子密度和土壤动物等5个因子均无差异;在距空旷地距离、距道路距离和灌木层盖度等3个因子均有差异;而其余因子则是在不同的两个物种之间有差异。主成分分析结果显示,黑颈长尾雉取食地前7个主成分的累计信息量达85·6%,白鹇的前6个达86·0%,红喉山鹧鸪的前5个达79·0%。影响这三种雉类取食地选择的因子主要集中于前3个主成分。3种雉类间取食地因子差异状态呈镶嵌分布,意味着种间生态位呈分化状态。各物种优先选择的因子组合不同,各因子的重要程度亦不一。     

Nuclear amination catalyzed by fungal laccases: Comparison of laccase catalyzed amination with known chemical routes to aminoquinones

Laccases are able to initiate nuclear amination of p-hydroquinones with primary aromatic amines, resulting in the formation of the corresponding monoaminated and diaminated quinones. Two laccase catalyzed reactions are compared with established synthetic routes to aminoquinones, showing that formation of products from laccase catalyzed reaction is comparable with reaction using sodium iodate as oxidant. Advantages and disadvantages of laccase catalyzed amination are discussed. It is concluded that laccase catalysis is less suitable than sodium iodate oxidation for the amination of simple p-hydroquinones with simple amines.     

未搅拌恒化器中单食物链模型的反应扩散方程组

本文研究一类描写未搅拌恒化器中单食物链模型的反应扩散方程组,用分定理证明正稳态解的存在性,并给出种群绝灭及持续生存的条件。