On sample size and inference for two-stage adaptive designs

Proschan and Hunsberger (1995, Biometrics 51, 1315-1324) proposed a two-stage adaptive design that maintains the Type I error rate. For practical applications, a two-stage adaptive design is also required to achieve a desired statistical power while limiting the maximum overall sample size. In our proposal, a two-stage adaptive design is comprised of a main stage and an extension stage, where the main stage has sufficient power to reject the null under the anticipated effect size and the extension stage allows increasing the sample size in case the true effect size is smaller than anticipated. For statistical inference, methods for obtaining the overall adjusted p-value, point estimate and confidence intervals are developed. An exact two-stage test procedure is also outlined for robust inference.     

The many shapes of mitochondrial membranes

The roles of mitochondria in cell death and in aging have generated much excitement in recent years. At the same time, however, a quiet revolution in our thinking about mitochondrial ultrastructure has begun. This revolution started with the use of vital dyes and of green fluorescent protein fusion proteins, showing that mitochondria are very dynamic structures that constantly move, divide and fuse throughout the life of a cell. More recently, some of the first proteins contributing to these various processes have been discovered. Our view of the internal structures of mitochondria has also changed. Three-dimensional reconstructions obtained with high voltage electron microscopy show that cristae are often connected to the mitochondrial inner membrane by thin tubules. These new insights are brought to bear on the wealth of data collected by conventional electron microscopic analysis.     

Genomic‐scale comparison of sequence‐ and structure‐based methods of function prediction: Does structure provide additional insight?

A function annotation method using the sequence-to-structure-to-function paradigm is applied to the identification of all disulfide oxidoreductases in the Saccharomyces cerevisiae genome. The method identifies 27 sequences as potential disulfide oxidoreductases. All previously known thioredoxins, glutaredoxins, and disulfide isomerases are correctly identified. Three of the 27 predictions are probable false-positives. Three novel predictions, which subsequently have been experimentally validated, are presented. Two additional novel predictions suggest a disulfide oxidoreductase regulatory mechanism for two subunits (OST3 and OST6) of the yeast oligosaccharyltransferase complex. Based on homology, this prediction can be extended to a potential tumor suppressor gene, N33, in humans, whose biochemical function was not previously known. Attempts to obtain a folded, active N33 construct to test the prediction were unsuccessful. The results show that structure prediction coupled with biochemically relevant structural motifs is a powerful method for the function annotation of genome sequences and can provide more detailed, robust predictions than function prediction methods that rely on sequence comparison alone.     

应用模糊数学评价观叶植物的观赏性

应用模糊数学方法评价52种观叶植物的观赏性,确定各种植物所处等级及又同一级别的排序,讨论模糊数学方法对于评价多指标且指标难以量化的多样品的优劣等级与名次的先进性与不足。     

粗糙集模糊聚类分析法在昆虫分类研究中的应用

本文根据昆虫图像,对半翅目、鳞翅目、鞘翅目的28种昆虫提取的形状参数、叶状性、球状性等7项数学形态特征进行了粗糙集模糊聚类分析。在粗糙集处理的基础上,分别进行7指标和3指标（相对约简）两种不同的模糊聚类分析法相比较。结果显示,在作为目级阶元分类指标时,各项特征的重要性依次为：(似圆度、偏心率)＞（亮斑数、球状性、圆形性）＞（叶状性、形状参数）;粗糙集分类正确率优于模糊聚类分析法;粗糙集处理后的3指标分类正确率优于未处理的7指标分类正确率。结论认为,粗糙集理论在昆虫依据数学形态特征进行分类方面与统计分析方法相比更有优势,粗糙集滤过指标后再进行模糊聚类法分析在昆虫分类研究上具有重要意义。     

;;模块通过对计算机网络的现

36I;冯燕;122-123加快社区医疗服务建设步伐探讨黄红明;许明伟;韶关学院医学院,韶关学院医学院 广东韶关512026,广东韶关512026社区医疗服务;;建设;;步伐探讨加快社区医疗服务建设步伐,应突出重点,抓好6方面工作:(1)加大领导力度;(2)提高社区医疗服务从业人员素质;(3)改善社区卫生机构的基础设施;(4)切忌盲目扩张,无序发展;(5)强化社区卫生机构的     

πPS Sampling Scheme Through Grouping

A πPS sampling scheme is developed by combining Stevens and Midzuno-Sen Sampling schemes. The restriction on original probabilities is less severe in the proposed scheme than that in Stevens and Midzuno-Sen schemes. The performance of the scheme is satisfactory.     

环渤海沿海地区土地承载力时空分异特征

沿海地区是中国未来社会经济发展的重点区域,近年来沿海地区人地矛盾越来越突出,研究沿海地区土地承载力具有重要意义。针对以往评价中的不足,采用韦伯-费希纳定律确定指标评价标准;利用D-S证据理论进行主客观综合权重的计算,运用可变模糊集理论及模型对土地承载力进行综合评价,并以环渤海沿海地区进行实例分析。研究结果表明,2000—2011年,环渤海地区土地承载力整体呈持续上升趋势,但空间分布差异显著,天津、唐山、大连、盘锦、青岛、烟台、东营、威海土地承载力相对较高,锦州、营口、秦皇岛、滨州、潍坊、日照属于中等水平,沧州、丹东、葫芦岛四市土地承载力相对较低。可变模糊评价模型应用于土地承载力评价,计算简便,可操作性强,评价结果可信度高。     

长白山云冷杉林不同演替阶段群落稳定性

以长白山杨桦次生林、云冷杉针阔混交林、云冷杉近原始林为研究对象,选择反映群落基本特征的种群更新潜力、土壤肥力(土壤水分和土壤养分)、林地生产力、物种多样性5项共22个因子,通过模糊数学的隶属函数值对不同演替阶段群落的稳定性进行评价.结果表明:云冷杉针阔混交林的更新潜力、土壤养分、林分生产力、物种多样性指标最高;云冷杉近原始林的土壤水分指标最高;3种森林群落的稳定性表现为云冷杉针阔混交林＞云冷杉近原始林＞杨桦次生林.     

Monitoring Copper Bioaccumulation in Cocoa from Copper-Based Pesticide–Treated Cocoa Farms Using Fuzzy Similarity Method

Cocoa production has been hindered by pests, leading to application of pesticides. These pesticide applications have raised health concerns. This study is therefore aimed at developing accumulation classifications for copper (Cu) in cocoa from plantations where Cu-based pesticides have been applied using fuzzy similarity method (FSM). Cocoa pods, seeds, leaves, and soil samples were collected from five different plantations from three states in Nigeria. The plant samples were digested using standard methods, whereas the Cu in soil samples was extracted with 1 M ammonium acetate. The products were analyzed for Cu using flame atomic absorption spectrophotometer. The Cu concentrations obtained were used to model the accumulation degree using FSM. The Cu concentrations were higher in the leaves than the seeds and the pods. The persistency of Cu was displayed by high concentrations (11.5–375 mg/kg) and enrichment factor in CRIN sites where this pesticide application has been stopped for over a decade. The leaves from Ondo sites had the highest Cu concentration, which indicates impact of recent applications. The FSM membership function and algorithm indicated that the plant parts had low degrees of accumulation for fresh leaves, pods, and seeds, the valued part applied in beverages, but for the dry leaves, the accumulation degree is high. It may be concluded that the applied Cu-based pesticide had more impact and accumulation on the leaves than the commercial valued seeds, but the Cu concentration in the seeds is above the recommended value.