bluuebunny/crossref_metadata_2025 huggingface dataset:
Axial mass transfer in Taylor flow through circular microchannels
Authors: Salman Wael , Gavriilidis Asterios , Angeli Panagiota
Published: May 2007

A Computational Fluid Dynamics (CFDrpar; model has been formulated to evaluate axial mixing in Taylor flow. The residence‐time distribution (RTD) curves of a Taylor flow unit cell (comprised of a liquid slug and two half bubbles) is calculated numerically from a step‐tracer simulation by solving the steady‐state Navier‐Stokes and the transient convection‐diffusion equations for a variety of conditions (10 < Pe < 105, 10−5 < Ca < 10−3). The concentration calculated at the outlet of a unit cell gives the cell‐density function, from which its RTD curve can be found. Two different trends in the unit cell RTD curves were observed with Pe. At high Pe, the curves have characteristic peaks, while at low Pe only one peak is found that decays slowly. The size and separation of the peaks is affected by the Pe, film thickness δ, and slug length, but not Re. The moments of the RTD curves are then used to assess literature unit cell models (CSTR‐PFR, two‐region, and the model of Thulasidas et al.1) For Peδ > 10 the CSTR‐PFR model showed the largest difference from the CFD simulations, while the model by Thulasidas et al. showed reasonable agreement. The two‐region model fitted the simulations, but only for Sh values significantly different from those found by literature correlations. For Peδ < 10, the CSTR‐PFR model gave the best predictions compared to the numerical simulations. A method for calculating the residence‐time distribution of a reactor, based on the residence‐time distribution of a unit cell by means of a convolution method, was also introduced and gave results which compared very well with experimental data. The short length of the reactor used in the experiments, however, could not allow proper differentiation from other models investigated, which also showed good agreement with the experimental data. © 2007 American Institute of Chemical Engineers AIChE J, 2007
Considering of certain relevant information in the analysis of contingency tables. A three‐step procedure
Authors: Enke H.
Published: May 2007

A heuristic three‐step procedure for analysing multidimensional contingency tables is given to meet the requirements of a mixed analysis from both hypotheses‐ruled and data‐ruled type. The first‐step provides the structure of relationships among the attributes by fitting an appropriate unsaturated log‐linear model to the data of the given contingency table. Restriction to elementary hierarchical models allows to get them by combining pairs of conditional independence. The result of the first step may be regarded as a certain validisation of real model ideas. In the second step the significant pairs of conditional dependence are analysed in regard to the levels of the condition complex. Only such significant pairs are to be considered, in general, where the condition complex does not include the response variable. The third‐step may test special subtests in that significant two‐dimensional tables found in step two or may extend the general statements by partitioning, the corresponding test statistics in additive components. Application examples demonstrate the general line of action.
Testing Linear Contrasts of Means in Experimental Design Without Assuming Normality and Homogeneity of Variances
Authors: Tiku M. L.
Published: May 2007

We investigate the efficiencies of TIKU'S (1967, 1980) modified maximum likelihood (MML) estimators of location and scale parameters of symmetric distributions and show that they are remarkably efficient (jointly). We develop test statistics (based on MML estimators), analogous to the classical tests based on sample means and variances, for testing the equality of two means (the population variances not necessarily equal). We show that these tests are remarkably robust to distributional assumptions and generally more powerful than the well‐known nonparametric tests (WILCOXON, normal‐score, KOLMOGOROV‐SMIRNOV). We generalize the results to testing linear contrasts of means in experimental design (the error variances not necessarily equal). We show that the analogous tests based on ‘adaptive’ robust estimators (wave, bisquare, HAMPEL,) etc., GROSS (1976, and other ‘adaptive’ robust estimators) give misleading Type I errors.
Unbalancedness and Efficiency in Estimating Components of Variance: MINQUE and ANOVA Procedure
Authors: Ahrens H. , Sanchez J.
Published: May 2007

We consider the one‐way classification random model. Using a measure of unbalancedness some MINQ‐Estimation procedures and ANOVA‐procedure have been investigated with respect to their sensibility to unbalancedness.

Further if we define the efficiency of a design N as the ratio of the MSE (.)'s of the balanced and the unbalanced case we obtain for three MINQE‐procedures upper and lower bounds of the minimum efficiency.
Use of the Likelihood Ratio Test on the Uniform Distribution
Authors: Shoukri Mohamed M.
Published: May 2007

In this article we give a simple procedure to determine the exact distribution of the likelihood ratio test of a statistical hypothesis regarding the parameter of the uniform distribution. The resulting distribution will be shown to serve as an approximation to the distribution of the likelihood ratio statistic for testing the equality of scale parameters of k independent Exponential populations.
Omnibus Two‐Sample Test Procedures with Randomly Censored Data
Authors: Koziol J. A. , Yuh Y. S.
Published: May 2007

Versions of the KOLMOGOROV‐SMIRNOV, KUIPER, and cRAMéR‐VONMISESstatistics are introduced for the problem of comparing the underlying survival distributions of two populations when observations are subject to random censorship, and a two‐sided alternative is of interest. These statistics are shown to have readily amenable asymptotic distributions; furthermore, the statistics reduce to their classical counterparts in the absence of censorship. Data pertaining to a cancer chemotherapy experiment are examined with these statistics.
Sequentially Generated Designs
Authors: Vuchkov I. N.
Published: May 2007

Procedures for sequential generation of nearlyD‐optimal designs are described. Two kinds of designs can be obtained: symmetrical block designs and nonsymmetrical ones. It is shown that in a special case when the number of the support points of a continuousD‐optimal design equals to the number of regression coefficients the sequential designs can be constructed very easy without use of a computer. A Catalogue containing 135 designs has been developed by use of these procedures. 34 of them can be used for experiments in cuboidal factor space and the remaining for experiments with mixture and process variables. Comparison with other designs is done.
On the Optimality of F‐test on Variance Components in Mixed Linear Models
Authors: Roebruck P.
Published: May 2007

The analysis‐of‐variance tests for hypotheses on random effects in regular linear models are considered. Conditions are given for these tests to be uniformly most powerful unbiased or uniformly most powerful invariant unbiased. An example shows that the difference between these conditions can be serious.
Construction of Selection Indexes with Restrictions
Authors: Mielenz N.
Published: May 2007

In this paper the problem of unistage selection with inequality constraints is formulated. If the predictor and criterion variables are all normally distributed, this problem can be written as a convex programming problem, with a linear objective function and with linear constraints and a quadratic constraint. Using the duality theory, for convex nonlinear programming it is proved, that its dual problem can be transformed into a convex minimization problem with non‐negativity conditions. Good computational methods are known for solving this problem. By the help of the dual problem sufficient conditions for a solution of the original primal problem are derived and illustrated by an example of practical interest.
The Exact Evaluation of 2‐way Cross‐classifications: The Combinatory Distribution
Authors: Kannemann K.
Published: May 2007

A practical methodology is presented for the exact combinatory evaluation of 2‐way cross‐classifications. The combinatory distribution is based on a test‐statistic relating to the information content of an observed table. Several examples of exact evaluation accompany this presentation.
Bayesian Prediction Regions for the Extreme Order Statistics
Authors: Lingappaiah G. S.
Published: May 2007

In this paper, prediction bounds for the order statistics are dealt with. For this purpose, predictive distributions derived by Bayesian approach, are utilized. In particular, bounds for the smallest and the largest order statistics are set when a series of samples are drawn from exponential, Pareto and power function populations. These bounds assist in knowing the nature of these predicted statistics even without actually having the sample observations.
Construction of Estimation Regions for the Parameters of Explicit Functional Relationships
Authors: Bandemer H. , Schmerling S.
Published: May 2007

Assuming that some explicit functional relationship acts as a mathematical model we consider the case that we are given a finite set of hypercuboids, each of which contains at least one point of the true functional relationship with a certain given probability. We present a procedure to construct sets for the unknown parameters and probabilities for the event that those contain the true parameter value. The procedure is illustrated by an example from pharmaceutical technology.
On Some Stochastic Problems in Epidemiology under the Binomial Damage Model
Authors: Rao B. Raja
Published: May 2007

The present paper discusses some probability problems in epidemiology in which a community is divided into two parts by means of the binomial damage model. The community size N is an integer‐valued random v̀ariable and p denotes the incidence rate of a certain disease such that conditional on N=n, the number B of infected individuals in the community follows a binomial distribution with parameters n and p. Let C denote the number of the susceptibles, where B + C = N. Probabilities are found of the events, such as, only half the community is hit by the disease, or there are n more susceptibles than are infected for n=0, 1, 2,…, or the susceptibles exceed the infected, or the susceptibles exceed (m‐1) times the number of infected individuals for m = 2, 3,…, etc. These probabilities play an useful role when a public health official wishes to ascertain that only a given proportion 1/m of the community is infected with the disease. Only the cases when the community size N follows the geometric, negative binomial or FISHER'S logarithmic series distributions are considered with the mathematics being manageable.
A Technique for Evaluating Forecasting Models
Authors: Xekalaki E. , Katti S. K.
Published: May 2007

The paper presents a new methodology for evaluating the performance of a forecasting model. The evaluation‐criterion utilizes a “credibility interval” centered at the model prediction. Given predicted and observed values, the length of the “credibility interval” is increased (or decreased) according as an observed value of the dependent random variable falls out of (or into) the interval. Based on that, various ways of assessing the rating of the model are discussed and illustrative examples are given.
Testable Hypotheses Implied by a Linear Hypothesis
Authors: Stepniak C.
Published: May 2007

ROY and ROY have shown that for any linear hypothesis H being not testable it is possible to construct a testable hypothesis which is implied by H. A maximal testable hypothesis implied by H is presented.
On the Application of Ordinate Characterizing of Approximately Periodical Functions in Analyzing Biological Records
Authors: Bandemer H.
Published: May 2007

As a possible alternative to spectral analysis of biological processes the method of thresholding the recorded function is reconsidered. The frequencies of the section length for a finite set of levels form the frequency surface which is the starting point for inference and reasoning. The paper presents ideas and examples to stimulate the development and use of a suitable electronic equipment.
Diminished Confidence Levels in the Interval Estimation of an Unknown Regressor in Model I of Linear Regression
Authors: Horn M. , Rausch W.
Published: May 2007

For the modely=β0+ β1x +e(model I of linear regression) in the literature confidence estimators of an unknown positionx0are given at which either the expectation ofyis given (see FIELLER, 1944; FINNEY, 1952), or realizations ofyare given (see GRAYBILL, 1961). These confidence regions with level 1—α need not be intervals. The occurrence of interval shape is a random event. Its probability is equal to the power of thettest for the examination of the hypothesisH: β1= 0. The papers mentioned above claim to provide confidence intervals with level 1 − α. But because of the restriction of (1 —α)—confidence regions to intervals the true confidence probability is the conditional probabilityWc:

Wc=P(the confidence region coversx0| the region has interval shape). Here this conditional probability is shown to be less than 1 —α. Evidence on the possible deviations from 1 —α has been obtained by simulations.
Zur Versuchsplanung für Schätzungen im gemischten Modell der linearen Regression1
Authors: Bartko M.
Published: May 2007

The covariance matrix of the least‐squares‐estimator for the coefficients of the mixed model of linear regression is deduced. This serves as a base to work out procedures experimental design for point and confidence estimations of the regression coefficients and the regression function. So it was shown, that the C‐, A‐, D‐ and G‐optimal designs in the mixed model are the same as in model I. Further an assertion for sample size determination is proved especially for point estimation of the regression function.
A Symmetric Bivariate Binomial Distribution and Its Application to the Analysis of Clustered Samples in Medical Research
Authors: Le Chap T.
Published: May 2007

A reasonable and computationally straightforward method is proposed for use to analyze clustered samples in medical research. Results are illustrated with examples in ophthalmology and otolaryngology.
Randomized Blocks Analysis for the Exponential Distribution
Authors: Lachenbruch Peter A. , Woolson Robert F.
Published: May 2007

A procedure for analyzing randomized blocks experiments for uncensored exponential random variables is presented. Its small sample behavior is studied in several simulations. Sample size requirements are given.
Analyses of associations with censored data by generalized Mantel and Breslow tests and generalized Kendall correlation coefficients
Authors: Schemper M.
Published: May 2007

Two nonparametric procedures are proposed for the problem of testing association between two continous variables, when one is subject to arbitrary censoring. The main advantages of the two tests—generalizations of MANTEL'S (1066) and BRESLOW'S (1970)k‐sample tests for censored data—are: accurate control over the size of the test, no restrictive assumptions concerning censoring mechanisms, theoretical properties similar to those already explored for Mantel's and Breslow's tests, close relationship to descriptive measures of association, namely generalized Kendall correlation coefficients, to which part of the paper is devoted. Finally stratified analyses are discussed and calculated examples presented.
A Measure of Biochemical Individual Variability
Authors: Masuyama M.
Published: May 2007

Once a questionable substance is found in a polluted area, we determine its MLD, LD50 etc. by animal experiments and then taking the species difference into consideration, we provide its MTD, LD50 etc. for the man. However, there exists clearly a wide difference in its tolerance among persona even with the same sex and age belonging to the same race. Our main themes are (i) what is a rational measure of the biochemical individual variability, (ii) what kind of empirical law holds with respect to this measure, and (iii) what is the reason why it holds. This is a summary of my research sponsored by our Agency of Science and Technology [1979a] with some additional results.
A Sometimes‐Pool Estimator of the Mean Life
Authors: Ramkaran  , Bhattacharya Samir K.
Published: May 2007

The paper deals with the problem of estimating the mean life θ in an exponential model \documentclass{article}\pagestyle{empty}\begin{document}$f(x/\theta ) = \frac{1}{\theta }e - x/\theta$\end{document}. It is assumed that in addition to the current ordered sample, we have a sample collected sometime in the recent past when the mean life might have been β. We have proposed a Sometimes—Pool procedure which is based on the outcome of a preliminary test of H0: θ=β and obtained the expressions of the bias and MSE. An attempt has been made to locate that region in the parameter space in which the proposed estimator does better (in MSE sense) than the usual estimator based only on the current sample.
Exact Test Procedures for Generalized Kendall Correlation Coefficients
Authors: Schemper M.
Published: May 2007

An exact test of KENDALL'S tau is presented, useful in small samples when the asymptotic test may not be adequate. The procedure is proposed especially for situations when ties and/or censored observations are present in the variables to be analyzed by KENDALL'S tau. The paper describes generalizations of the procedure, presents calculated examples and offers a computer program, which facilitates the usage of the proposed procedure.
A Modification of Kappa for Interobserver Bias
Authors: Krauth J.
Published: May 2007

By COHEN and others the kappa index was developed for measuring nominal scale agreement between two raters. This statistic measures the distance from the nullhypothesis of independent ratings of two observers. Here a modified kappa is introduced, which takes into account the distance between the marginal distributions, as well. This distance is interpreted as the so‐called interobserver bias. Population analogues are defined for the modified kappa and a related conditional index. For these parameters asymptotic confidence intervals and tests are derived. The procedures are illustrated by fictitious and real examples.
A Problem of Equivalence in Clinical Trials
Authors: Patel H. I. , Gupta G. D.
Published: May 2007

Several methods exist for testing the bioequivalence in bioavailability trials. In this article we propose a method for testing the equivalence of two drugs in clinical trials when the response variable is assumed to have a normal distribution. The null and alternative hypotheses are formulated in a nonconventional manner. Computing aspects for the power and sample size are discussed.
On the Use of Ranks in Combined Estimates in Quantal Bioassays
Authors: Bennett B. M.
Published: May 2007

If {Ui} i = 1, …, k is a sequence of binary responses of ni subjects at each of k successive dose levels xi, there is the problem of the statistical treatment of the observed proportions Pi = Ui/ni when neither the probit nor the logit transformation may be assumed.

This paper considers the use of the midranks of the responses for point and interval estimation of relative potency in the case of parallel line assay in particular. More generally the problem of combining the results of several independent estimates using ranks is discussed. Several examples illustrate the method.
A Combined Product Estimator in Sample Survey
Authors: Kaur Parvinder
Published: May 2007

For the estimation of the population mean in stratified random sampling a ‘Combined Product Estimator’ is proposed which is more efficient than the ‘Combined Ratio’ and ‘Separate Ratio’ estimators. Also, the proposed estimator have exact expressions for bias and mean square error. An empirical illustration is given to compare the efficiencies of different estimators.
A Study of Maternal and Maternal Interaction Effects in Diallel Crosses
Authors: Kaushik L. S. , Puri P. D.
Published: May 2007

The analysis of diallel crosses by including the components due to maternal effect and maternal interaction effects have been presented for Griffing method—1 (random effect model) and Griffing method—3 (fixed and random effect model). Wherever exact test of significance is not possible, testing procedure using Satterthwaite (1946) approximation has been presented.
Random Networks of Catalytic Biochemical Reactions
Authors: Sonntag I.
Published: May 2007

Formulae for the probabilities of cycles and components are obtained for large random networks by combinatorical considerations and computer experiments. Formulae for the occurrence and distribution of cycles and of components of certain number and size are received for random networks.
Application of the Percolation Theory to Random Networks of Biochemical Reactions
Authors: Sonntag I.
Published: May 2007

Percolation Theory is used to get statements about random networks. It can be seen that the probability distribution that vertices belong to a finite cluster in dependence on the mean catalytic activity C = K/N has an analogy to phase transition of second kind.
On Admissible Estimators in a Linear Model
Authors: Stepniak C.
Published: May 2007

Let Y be observable random vector such that EY=Xβ and D(Y)=ρ2V. Linear estimation of a parameter p′β under the squared loss is considered. RAO, 1976 and 1979, obtained a necessary and sufficient condition for admissibility of an estimator t′Y in the case X=I. This result will be extended for arbitrary X.

AMS 1970 subject classifications. Primary 62J05; secondary 62C15.
The Additive Risk Model for Epidemiologic Interaction and the Analogy with Factorial Experiments
Authors: Rao B. Raja , Enterline Philip E.
Published: May 2007

The present paper may be divided into two parts.

The first is concerned with DAYAL'S (1980) discussion drawing a parallel between the concept of interaction in factorial experiments and the concept of epidemiologic interaction (synergism). The analogy works well with two risk factors. It is shown that generalizing this analogy to three or more factors does not give the Hogan et al. measure, also called the Interaction Contrast of Disease Rates (I.C.D.R.). As a consequence, Dayal's measure will not vanish when the factors act independently, unless some further condition is imposed, as he does.

The problem discussed in the second part is to relate the Interaction Contrast of Disease Rates (I.C.D.R.) corresponding to m binary risk factors with the I.C.D.R.'s corresponding to fewer than m risk factors. There are 2m — m — 1 subsets containing two or more risk factors and interaction has been considered between factors in each subset. The term ‘marginal I.C.D.R.’ has been introduced for the I.C.D.R. involving the factors in a subset in the absence of all the rest of the factors. The special cases of m = 3 and m = 4 are discussed in detail with the mathematics being manageable. When m = 3, there is one three‐factor I.C.D.R DXYZ and three two‐factor marginal I.C.D.R's DXY, DYZ, and DZX. This paper connects DXYZ with the average two‐factor marginal I.C.D.R. Similarly when m = 4, the four‐factor I.C.D.R. is connected with the average two‐ and three‐factor I.C.D.R.'s. The application of this result lies in showing, for example, that if all pairs of factors interact, then the three‐factor I.C.D.R is not only positive but has a positive lower bound, which is the average pairwise marginal I.C.D.R. Similarly if all the triplets of factors interact, the four‐factor I.C.D.R. has a positive lower bound. A numerical example illustrates the results obtained.
On Construction of Some Augmented Block Designs
Authors: Ceranka B. , Chudzik H.
Published: May 2007

Augmented block designs are frequently used in practice. In this paper procedures of construction of some types of augmented block designs are discussed using the concept of efficiency‐balance and partially efficiency‐balance.
Analysis of Crossover Designs with a Categorical Response
Authors: Le Chap T. , Cary Margaret M.
Published: May 2007

In the analysis of two‐period crossover designs, one frequently must consider the case of a categorical response with binary as a special case. These circumstances are considered in this paper and the proposed method—an extension of GART'S tests for the binary case—is similar to that of PIKE, CASAGRANDE and SMITH for the analysis of pair‐matched case‐control studies. The results are illustrated with a numerical example.
Some Simple Statistics to Test Against Ordered Alternatives in Complete Block Designs
Authors: Salama I. A. , Quade Dana
Published: May 2007

Consider testing the hypothesis of no treatment effects against a postulated ranking of the m treatments, given data from n Complete Blocks. A suitable test statistic is the weighted average rank correlation w = σbQiCi where Ci is the correlation between the postulated ranking and the ranking observed within the ith block, Qi is the rank of the ith block with respect to credibility, and the bi's are weights such that 0 ≦ b1 ≦ … ≦ bn. In this paper we introduce some simple statistics: the first extends the signed‐rank statistic to m ≦ 3, the second uses a simple measure of correlation based on the antirank, and the third a statistic based on Spearman's footrule. Tables for critical values are provided and the normal approximation is investigated.
Construction of Partially Balanced Incomplete Block Designs with Nested Rows and Columns
Authors: Agrawal H. L. , Frasad J.
Published: May 2007

A number of methods of construction of partially balanced incomplete block designs with nested rows and columns are developed and new balanced incomplete block designs with nested rows and columns are obtained as a by‐product.
Analysis of Row‐Column Experiments Involving Several Non‐Interacting‐Sets of Treatments and Multistage Youden Square Designs
Authors: Singh N. P. , Singh Gulab
Published: May 2007

This paper advances a procedure of analysis of designs eliminating heterogeneity in two directions, when there are ‘S’ non‐interacting sets of treatments. The analysis of multistage youden designs of HEDAYAT et al. (1972) which is a particular member of this class, has been given.
Two‐Group Classification when Both Groups are Mixtures of Normals
Authors: Rawlings R. R. , Graubard B. I. , Rae D. S. , Eckardt M. J. , Ryback R. S.
Published: May 2007

In this paper we consider a two‐group discriminant analysis problem where each group is a mixture of two subgroups. Based upon data from a clinical study of alcohol involvement and diseases, simulation experiments were performed for three different configurations of means and covariance matrices. Expected actual non‐error rates are estimated for the linear, quadratic, and kernel discriminant functions for sample sizes 30, 50, 75, 100, 150 and 200. A conclusion of the article is that the kernel discriminant function performs as well as or better than quadratic discriminant function. However, the linear discriminant function was clearly inferior to either the quadratic or kernel discriminant functions.
Mortality of a Heterogeneous Cohort; Description and Implications
Authors: Nour El‐Sayed
Published: May 2007

A recent model for heterogeneous mortality by VAUPEL et al. (1979) is shown to be based on incorrect definitions. An alternative formulation is presented. The results indicate that current methods for computing the survivorship and life expectation functions underestimate the true values. A method is given for determining the possible magnitude of this underestimation. The method is illustrated by a numerical example using U.S. data.
The Application of Hunter's Inequality in Simultaneous Testing
Authors: Bauer P. , Hackl P.
Published: May 2007

Using the inequality given by HUNTER(1976) critical limits are derived on the basis of bivariate distributions of the respective statistics for various situations of simultaneous hypothesis testing. The gain in power as compared to the widely used Bonferroni‐inequality can be considerable if at least some of the simultaneously investigated test‐statistics are highly correlated. In such situations, the loss in power as compared to the use of the exact critical limits might be negligible for practical purposes, the exact limits often being hardly accessible.
A Simultaneous Test for Interactions which in the Model of the Analysis of (co)variance are Assumed not to Occur
Authors: Guiard V.
Published: May 2007

In this paper a simple test is described, with which it is possible to check the assumption that in the cases of analysis of variance or covariance several interactions don't occur. This test is particularly useful also if some subclasses are empty and in the case of unequal subclass numbers in model I, model II and the mixed model.
Treatment Evaluation by Incremental Crossover Designs
Authors: Hüsler J. , Lienert G. A.
Published: May 2007

Following GRIZZLE (1965) and JESDINSKY et al. (1981) it is suggested to replace the traditional two‐groups (AB, BA) crossover design by a four‐groups (AA, AB, BA, BB) design in order to control for treatment‐period interactions (carry‐over effects). Contrary to the above authors it is proposed to use the increments D = X2 ‐ X1 from 1 st to 2 nd observations rather than the observations themselves as the dependent variable. Testing for main‐ and interaction effects of treatment is treated for increment modified Grizzle‐ and Jesdinsky ANOVA models. Alternative and conditional tests are discussed. Numerical evaluations are illustrated by an example from psychopharmacology.
The Use of Adaptive Blocks in the Design of Clinical Trials
Authors: Srinivasan R. , Wharton B. M.
Published: May 2007

This paper introduces a class of data‐dependent allocation rules for use in sequential clinical trials designed to choose the better of two competing treatments, or to decide that they are of equal efficacy. These readily understood and easily implemented rules are shown to reduce, substantially the number of tests with the poorer treatment for a broad category of experimental situations. Allocation rules of this type are applied both to trials with an instantaneous binomial response and to delayed response trials where interest centers on exponentially distributed survival time. In each case, a comparison of this design with alternative designs given in the literature shows that the proposed design is superior with respect to ease of application and is comparable to the alternatives regarding inferior treatment number and average sample number. In addition, the proposed rules mitigate many of the difficulties generally associated with adaptive assignment rules, such as selection and systematic bias.
On the Rotation of Canonical Solutions
Authors: Röhr M.
Published: May 2007

Some points of CLIFF/KRUS's important rotation procedure are criticized. This result in the definition of simple structure of canonical solutions, the use of STEWART/LOVE's redundancy index as a measure of common variance, and two new rotation procedures (HAKSTIAN's modified varimax rotation, separate rotation of both sets). The objects of rotation should be the (intraset) loadings.
Robust Univariate Two‐Way Classification
Authors: Balakrishnan N. , Tiku M. L. , Shaarawi A. H. El.
Published: May 2007

We develop a robust classification procedure, based on TIKU'S (1967, 1980, 1982) MML (modified maximum likelihood) estimators, for classifying an observation in one of the two populations π1 and π2 and show that this procedure is superior to the classical and nonparametric procedures.
Evaluating an Explicit Functional Relationship by Fuzzifying the Statement of its Satisfying
Authors: Bandemer H. , Schmerling S.
Published: May 2007

Combining the concepts of interval arithmetic and fuzzy theory the observations to identify some explicit functional relationship are assumed to be fuzzy sets given by the threshold sets of their membership function, which have contours suitable for the application of interval arithmetic procedures. The result is a fuzzy set on the parameter region, which offers possibilities for reasoning on the validity of the relationship. The proceeding is illustrated by an example.
Use of the Score Statistic for Testing Goodness‐of‐Fit of Some Generalised Distributions
Authors: Rayner J. C. W. , McIntyre R. I.
Published: May 2007

The use of the score statistic to test whether a generalised distribution gives an improved fit over a non‐generalised distribution is recommended. The score statistic for a generalised exponential family is derived. Several specific examples are given.
A Comparison of the MPN and Fisher‐Yates Estimators for the Density of Organisms
Authors: Best D. J. , Rayner J. C. W.
Published: May 2007

The method of moments estimator, discussed in FISHER and YATES (1970), for the density of bacteria is compared with the maximum likelihood or MPN estimator: For sample sizes used in practice the estimators are found to be very similar. Estimators which reduce bias are discussed and their use recommended.
A Note on the Analysis of ap× 22Design
Authors: McKee B. , Kshirsagar A. M.
Published: May 2007

TYAGIhas given a method of constructing a balanced factorial experiment of thep× 22type. A complete analysis of such a design with and without recovery of interblock information, using the eigenyalues and eigenvectors of theC‐matrix of the design, is given in this paper. KHATRY& SHAH'Smethod of producing uniformly better estimators is employed to combine the inter and intra block estimates.
Problems in Estimating the Minimum Number of Genes Contributing to Quantitative Variation
Authors: Mayo O. , Hopkins A. M.
Published: May 2007

This note emphasizes the problems inherent in gene counting methods like the Castle‐Wright index and questions their utility.
An Application of Logistic Models to the Analysis of Ordinal Responses
Authors: Greenland Sander
Published: May 2007

Logistic probability models—models linear in the log odds of the outcome event—have found extensive application in modelling of unordered categorical responses. This paper illustrates some extensions of logistic models to the modelling of probabilities of ordinal responses. The extensions arise naturally from discrete probability models for the conditional distribution of the ordinal response, as well as from linear modelling of the log odds of response. Methods of estimation and examination of fit developed for the binary logistic model extend in a straightforward manner to the ordinal models. The models and methods are illustrated in an analysis of the dependence of chronic obstructive respiratory disease prevalence on smoking and age.
Some Approximations of the Borel‐Tanner or the Generalized Poisson Distribution
Authors: Khan M. S. H.
Published: May 2007

This paper considers some approximations for the Borel‐Tanner (Generalized Poisson) sums by using (i) Gram‐Charlier Poisson expansion, (ii) Mixture of two Poisson distributions, (iii) Variance stabilizing technique, and (iv) negative binomial distribution. It has been found that the approximation obtained by using the negative binomial distribution seems to be more efficient than the other approximation.
Critical Values of ‘Maximum Studentized Residual’ Statistics in Multiple Linear Regression
Authors: Paul S. R.
Published: May 2007

In multiple linear regression, test for the discordancy of a single outlier in the response variable is usually based on the ‘maximum studentized residual’ statistic. Exact critical values for the test statistic t are not available. Upper bounds for the critical values have been found by SRIKANTAN (1961), PRESCOTT (1975) and LUND (1975). In this note we show that all these upper bounds are algebraically equivalent.
Comparison of Approaches to Multivariate Linear Calibration
Authors: Naes T.
Published: May 2007

In this paper two approaches to multivariate linear calibration in linear models are compared. One of these approaches is based on knowledge of the distribution of the variable to be predicted. The other one uses only information about the measurement instrument. The methods are compared with respect to risk function and their functional relationship is analysed. When concerns risk functions we concentrate on asymptotic results.
Reduction of Linear Models Using Correct or Incorrect Prior Information
Authors: Toutenburg H.
Published: May 2007

When there is no prior knowledge on the parameter vector β of the linear model then the LSE is most favourable at least in the class of linear unbiased estimators. On the other hand, in many practical problems one has some guessed estimate of β. Using this information leads to two‐step estimation procedures which may or may not dominate the LSE with respect to MSE. The dominance depends on the degree of incorrectness of the guessed parameter and is analyzed numerically for the case of sample reduction.
Application Fields of the Empirical Regression ‐ A Case Study
Authors: Peil J. , Schmerling S.
Published: May 2007

Empirical regression is defined as conditional expected value based on an estimation of a twodimensional density. It is a modelfree mathematical means for a first evaluation of measured data of an unknown stochastical relation between two quantities. The numerical procedures may be applied for calculation of the mean course of an unknown relation hidden in the measured data. Disregarding the statistical background an other aspect of application is the analyzing of time series, especially smoothing of time series and modelfree recording of the trend component in non‐stationary time series. The calculated regression curve provides an objective basis for comparing of different measured courses as well as for a further evaluation, e. g. in respect of a suitable choice of an analytical expression. The possibility of interpolation and the smoothing properties of empirical regression give essential advantages for internal regression as one step in the process of model construction.
Robustness of Statistical Tests in the Two‐Sample Location Problem
Authors: Marrero O.
Published: May 2007

A simulation study was performed to compare three statistical tests with respect to their performances in the two‐sample location problem for contaminated normal distributions. The three tests were: the t‐test, the rank‐transformed t‐test, and the Wilcoxon rank‐sum test. The results showed the t‐test to be inferior to the other two tests.
Improved quality evaluation of Radix Salvia miltiorrhiza through simultaneous quantification of seven major active components by high‐performance liquid chromatography and principal component analysis
Authors: Ma Hong‐Liang , Qin Min‐Jian , Qi Lian‐Wen , Wu Gang , Shu Pan
Published: May 2007

A novel method, using high‐performance liquid chromatography combined with principal component analysis, was developed for the quality evaluation of danshen through simultaneous determination of seven components, namely danshensu, protocatechuic acid, protocatechuic aldehyde, salvianolic acid B, tanshinone I, cryptotanshinone and tanshinone IIA. These seven components were simultaneously separated on a Zorbax SB‐C18 column. The mobile phase consisted of 0.05% phosphoric acid water and methanol:acetonitrile (1:1) with a gradient elution, and the detection wavelength was set at 280 nm. Thirty samples of danshen and its substitutes from different sources were investigated by the established method. The results showed that the content of each analyte varied considerably in different danshen samples. Among the seven components tested, salvianolic acid B, tanshinone IIA, cryptotanshinone, tanshinone I, danshensu and protocatechuic aldehyde were proved suitable and representative as chemical markers for the quality control of danshen except for protocatechuic acid. Moreover, principal component analysis was used for the similarity evaluation of different samples, and it could be straightforward and reliable to differentiate danshen samples of different origins. In conclusion, simultaneous quantification of multiple components by high‐performance liquid chromatography combined with principal component analysis would be a better strategy for the quality evaluation of danshen. Copyright © 2007 John Wiley & Sons, Ltd.
Association between chemical and genetic variation of Vitex rotundifolia populations from different locations in China: its implication for quality control of medicinal plants
Authors: Hu Yuan , Zhang Qiaoyan , Xin Hailiang , Qin Lu‐Ping , Lu Bao‐Rong , Rahman Khalid , Zheng Hanchen
Published: May 2007

Vitex rotundifolia is a widely distributed plant species that has been extensively used in traditional Chinese medicine. Its fruits, Fructus Viticis, are recorded as Manjingzi in the Pharmacopoeia of the People's Republic of China. For the effective quality control of its medicinal values reflected by chemical variation patterns, in addition to the relationship with genetic diversity, analyses based on high‐performance liquid chromatographic (HPLC) fingerprinting and inter simple sequence repeat (ISSR) molecular markers were carried out, involving 14 V. rotundifolia populations from different locations in China. The HPLC data showed considerable variation of chemical constituents among the V. rotundifolia populations. The hierarchical clustering analysis further revealed four major groups based on their chemotype variation. Abundant genetic diversity was detected among the V. rotundifolia populations that also were clustered into four groups based on their ISSR data. It is important to point out that the genetic variation pattern revealed by molecular markers was closely associated with that indicated by chemical constitutes in the fruits of V. rotundifolia. This finding provides a solid basis for the combined use of chemical and genetic fingerprints in efficiently evaluating qualities and choosing favourable chemotypes with appropriate pharmacological properties of V. rotundifolia, in addition to establishing good agricultural practices for medicinal plants. Copyright © 2007 John Wiley & Sons, Ltd.
Determination of clopidogrel in human plasma by liquid chromatography/tandem mass spectrometry: application to a clinical pharmacokinetic study
Authors: Shin Beom Soo , Yoo Sun Dong
Published: May 2007

A rapid and sensitive LC/MS/MS assay was developed and validated for the determination of clopidogrel in human plasma. Clopidogrel was extracted by single liquid–liquid extraction with pentane, and chromatographic separations were achieved on a C18column. The method was validated to demonstrate the specificity, linearity, recovery, lower limit of quantification (LLOQ), stability, accuracy and precision. The multiple reaction monitoring was based onm/ztransition of 322.2 → 211.9 for clopidogrel and 264.1 → 125.1 for ticlopidine (internal standard). The total analytical run time was relatively short (3 min), and the LLOQ was 10 pg/mL using 0.5 mL of human plasma. The assay was linear over a concentration range from 10 to 10,000 pg/mL (r> 0.999). The intra‐ and inter‐day accuracies were 101.3–108.8 and 98.4–103.5%, respectively, and the intra‐ and inter‐day assay precisions were 1.9–5.5 and 4.4–8.1%, respectively. The developed assay method was applied to a pharmacokinetic study in human volunteers after oral administration of clopidogrel at a dose of 150 mg. Copyright © 2007 John Wiley & Sons, Ltd.
Double‐Bridge Bonding of Aluminum and Hydrogen in the Crystal Structure of γ‐AlH3.
Authors: Yartys Volodymyr A. , Denys Roman V. , Maehlen Jan Petter , Frommen Christoph , Fichtner Maximilian , Bulychev Boris M. , Emerich Hermann
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Bridgman Crystal Growth of Yb2Ru3Ge4 — A Ternary Germanide with a Three‐Dimensional Network of Condensed Distorted RuGe5 and RuGe6 Units.
Authors: Schappacher Falko M. , Katoh Kenichi , Poettgen Rainer
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
V2Cu3Ga8, Mo2Cu3Ga8 and W2Cu3Ga8 — New Compounds with a Novel Order Variant of a bcc Packing and Motifs of Self‐Similarity.
Authors: Kuntze Verena , Lux Rainer , Hillebrecht Harald
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Synthesis of [F3SNXeF][AsF6] and Structural Study by Multi‐NMR and Raman Spectroscopy, Electronic Structure Calculations, and X‐Ray Crystallography.
Authors: Smith Gregory L. , Mercier Helene P. A. , Schrobilgen Gary J.
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
An Organically Templated Yttrium Fluoride with a “Super‐Diamond” Structure.
Authors: Stephens Nicholas F. , Lightfoot Philip
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
C3N4 as a Precursor for the Synthesis of NbC, TaC and WC Nanoparticles.
Authors: Li P. G. , Lei M. , Sun Z. B. , Cao L. Z. , Guo Y. F. , Guo X. , Tang W. H.
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Crystal Structure, Electronic Structure, and Physical Properties of Ti1‐δMo1+δ As4 and Ti1‐δMo1+δ Sb4.
Authors: Derakhshan Shahab , Assoud Abdeljalil , Kleinke Katja M. , Kleinke Holger
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
[Ni5Sb17]4‐ Transition‐Metal Zintl Ion Complex: Crossing the Zintl Border in Molecular Intermetalloid Clusters.
Authors: Moses Melanie J. , Fettinger James C. , Eichhorn Bryan W.
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Imidazolium Ionic Liquids as Solvents for Cerium(IV)‐Mediated Oxidation Reactions.
Authors: Mehdi Hasan , Bodor Andrea , Lantos Diana , Horvath Istvan T. , De Vos Dirk E. , Binnemans Koen
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Deoxygenation of Sulfoxides, Selenoxides, Telluroxides, Sulfones, Selenones and Tellurones with Mg—MeOH.
Authors: Khurana Jitender M. , Sharma Vandana , Chacko Silvi A.
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Hydroboration of 1,1′‐Bi(cyclopent‐1‐ene) and 3,3′‐Biindene: Experimental and Theoretical Study.
Authors: Kvicala Jaroslav , Baszczynski Ondrej , Krupkova Alena , Stranska Denisa
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Acetyl Chloride‐Mediated Mild and Chemoselective Attachment and Removal of Tetrahydropyranyl (THP) Group.
Authors: Yeom Chang‐Eun , Shin Yong Je , Kim B. Moon
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.