Applications of Extensions of Bivariate Rank Sum Statistics to the Crossover Design to Compare Two Treatments Through Four Sequence Groups

Summary This article describes applications of extensions of bivariate rank sum statistics to the crossover design with four sequence groups for two treatments. A randomized clinical trial in ophthalmology provides motivating background for the discussion. The bilateral design for this study has four sequence groups T:T, T:P, P:T, and P:P, respectively, for T as test treatment or P as placebo in the corresponding order for the left and right eyes. This article describes how to use the average of the separate Wilcoxon rank sum statistics for the left and right eyes for the overall comparison between T and P with the correlation between the two eyes taken into account. An extension of this criterion with better sensitivity to potential differences between T and P through reduction of the applicable variance has discussion in terms of a conceptual model with constraints for within‐side homogeneity of groups with the same treatment and between‐side homogeneity of the differences between T and P. Goodness of fit for this model can have assessment with test statistics for its corresponding constraints. Simulation studies for the conceptual model confirm better power for the extended test statistic with its full invocation than other criteria without this property. The methods summarized here are illustrated for the motivating clinical trial in ophthalmology, but they are applicable to other situations with the crossover design with four sequence groups for either two locations for two treatments at the same time for a patient or two successive periods for the assigned treatments for a recurrent disorder. This article also notes that the methods based on its conceptual model can have unsatisfactory power for departures from that model where the difference between T and P via the T:T and P:P groups is not similar to that via the T:P and P:T groups, as might occur when T has a systemic effect in a bilateral trial. For this situation, more robust test statistics have identification, but there is recognition that the parallel groups design with only the T:T and P:P groups may be more useful than the bilateral design with four sequence groups.     

Reactor Engineering in Large Scale Animal Cell Culture

This article mainly addresses the issues associated with the engineering of large-scale free suspension culture in agitated bioreactors >10,000 L because they have become the system of choice industrially. It is particularly concerned with problems that become increasingly important as the scale increases. However, very few papers have been written that are actually based on such large-scale studies and the few that do rarely address any of the issues quantitatively. Hence, it is necessary very often to extrapolate from small-scale work and this review tries to pull the two types of study together. It is shown that ‘shear sensitivity’ due to agitation and bursting bubbles is no longer considered a major problem. Homogeneity becomes increasingly important with respect to pH and nutrients at the largest scale and sub-surface feeding is recommended despite ‘cleaning in place’ concerns. There are still major questions with cell retention/recycle systems at these scales, either because of fouling, of capacity or of potential and different ‘shear sensitivity’ questions. Fed-batch operation gives rise to cell densities that have led to the use of oxygen and enriched air to meet oxygen demands. This strategy, in turn, gives rise to a CO₂ evolution rate that impacts on pH control, pCO₂ and osmolality. These interactions are difficult to resolve but if higher sparge and agitation intensities could be used to achieve the necessary oxygen transfer, the problem would largely disappear. Thus, the perception of ‘shear sensitivity’ is still impacting on the development of animal cell culture at the commercial scale. Microcarrier culture is also briefly addressed. Finally, some recommendations for bioreactor configuration and operating strategy are given.     

A model of plant-to-plant movement of aphids: A new approach

1. A stochastic model was applied to the changes in the distribution of aphids on plants in a field determined by their plant-to-plant movements.
2. The expected numbers of aphids on plants were calculated for the 5 days of an experiment reported byShiyomi (1967) and compared with observed frequencies at these times.

     

The Relative Power of Two Asymptotic Multivariate Tests for Homogeneity in a Contingency Table

In a three way contingency table two multivariate tests for homogeneity have been proposed by the author (1983) a the “catanova” test, which is a trace “metric” test and b the “multinova” test which is determinant based. Both tests are asymptotically distributed as chi-square. In this paper, the power values of the tests are compared and conditions are given for preference of each test.     

Differences in egg wastage by superparasitism,contrastingVenturia (=Nemeritis) canescens searching singly versus searching in groups

A statistical and graphic study is presented of the wastage of eggs by Venturia (=Nemeritis) canescens when searching singly and in groups of 10 among hosts at four different host densities in laboratory universes as described byHuffaker andMatsumoto (preceding paper of this journal). The host insect was the fluour moth Anagasta kühniella and the host densities used were 10, 30, 100 and 200 per universe. Intensity of egg wastage due to superparasitim varied significantly according to host density, and between the two parasite densities employed, 1 and 10, using both F-tests and chi-square tests. Plots of k-factor analysis on this egg wastage showed high negative correlations with host density, and the raw data for single parasites was well represented by a parabola while that for the grouped parasites departed from this relationship only at the lowest host density.     

微生物能力验证样品均匀性试验的研究

目的：对人工制备的微生物能力验证样品进行均匀性试验,验证是否符合能力验证的要求。方法：随机抽取能力验证样品,采用AOAC990.12测试方法,菌落总数的结果经单因素方差分析评价其均匀性。结果：样品D均匀性试验结果为样品间变异较小,样品足够均匀;样品C均匀性试验统计学结果显示样品间差异存在显著性,通过借鉴方法的重复性和再现性的标准差对能力验证总体标准差进行评估,计算Sσ,该值小于能力验证的推荐值,该样品的均匀性可能满足能力验证的对样品要求。     

A circular analysis of chronobiology of Schistosoma japonicum cercarial emergence from hilly areas of Anhui,China

About 46 mammal species have been suspected as reservoir hosts for Schistosoma japonicum and therefore the track of the target parasites, in relation to definitive host species, may be of great importance in terms of theoretical and practical implications. The circadian rhythm of cercariae emergence, a genetically controlled behavior for parasites to adapt to their definitive hosts, may seem to be a perfect biological marker for S. japonicum. In this study, a late (or nocturnal) cercarial emergence pattern was observed on the parasites from one hilly region in Anhui of China, where rodents serve as reservoirs, and on the first generation of the parasites. Moreover, by using the circular statistics, the homogeneity of parasites in such trait was also demonstrated. All these provide evidence for the genetically controlled biological trait, which seems essential in the investigation of macro- or micro-dynamics of parasite transmission of interest. This is particularly true in the case of S. japonicum when multiple parasite isolates or strains are more likely to exist.     

成人型多囊肾病的遗传研究

３＇ＨＶＲ是成人型多囊肾病基因诊断中最常用的探针。我们分析了５１个无亲缘关系健康学生和３个成人多囊肾病家系的３＇ＨＶＲ－ＰｖｕＩＩ ＲＦＬＰ,所得多态信息用计算机软件ＬＩＮＫ－ＡＧＥ和ＨＯＭＯＧ进行连锁分析和同质性检验,其中１个家系致病基因位点与３＇ＨＶＲ不连锁,因而判定为ｎｏｎ ＰＫＤ１。剩下的两个家系中１个有明显的重组,但还不能判定为ｎｏｎ ＰＫＤ１,另１个与３＇ＨＶＲ连锁,属于ＰＫＤ１。成人