bluuebunny/crossref_metadata_2025 huggingface dataset:
Positioning functional foods in an ecological approach to the prevention of overweight and obesity
Authors: Wieringa N. F. , Van Der Windt H. J. , Zuiker R. R. M. , Dijkhuizen L. , Verkerk M. A. , Vonk R. J. , Swart J. A. A.
Published: February 2008

To contribute to the social debate about the role of functional foods in the prevention of overweight and obesity using an ecological model to study the positioning of functional foods and their social implications. Positioning was conceptualized as the relative attention given to functional foods within the range of preventive strategies, and the way in which they address specific causes of overweight. A systematic review was conducted to identify (A) preventive strategies aiming at the individual; (B) technological approaches; and (C) environmental strategies. All strategies were further classified according to the nature of causes they refer to – either individual or environmental. In the prevention of overweight/obesity, an emphasis on strategies designed to change the quality of food products and supplies has developed. Technological strategies particularly relate to functional foods; however, while providing a new dimension to food products, they do not challenge the underlying lifestyles causing overweight. Furthermore, they also stress individual responsibility for overweight/obesity and technological solutions to it. From a societal perspective, the characteristics of functional foods indicate that they can only be expected to play a limited role in overweight/obesity prevention. The ecological approach suggests that other strategies targeting individual and social causes need to be developed and marketed equally well.
THE DISTRIBUTION OF A GENERAL QUADRATIC FORM IN NORMAL VARIATES1
Authors: Robinson J.
Published: February 2008

The distribution of the difference of two independent chi‐square variates is given and the distribution of a general quadratic form in normal variates is obtained as a mixture of distributions of this type. Robbins and Pitman (1949) obtained the distribution of a general positive quadratic form in normal variates as a mixture of chi‐square distributions. The method used in Section 3 is simply a slight extension of their method.
A PROBABILISTIC DERIVATION OF THE NON‐CENTRAL χ2 DISTRIBUTION
Authors: Kerridge D.
Published: February 2008

A simple derivation of the non‐central χ2 distribution is presented. This requires no advanced mathematical knowledge, and is suitable for use in elementary courses.

The non‐central χ2 distribution is of great importance in statistical theory, both in its own right, and as a step in the derivation of other distributions; however, it tends to be neglected in statistical courses largely, it seems, because the standard derivations are too difficult. A recent review of derivations by Guenther (1964) shows that most require some knowledge of n‐dimensional geometry or the equivalent matrix theory. The alternative is the use of generating functions, which is straightforward, apart from the inversion back to the density function. An objection to such methods is that they give no insight into the probabilistic nature of the proble.
CUSTOMER OVERFLOW IN QUEUES WITH FINITE WAITING SPACE1
Authors: Bhat U. N.
Published: February 2008

The distribution of time of first overflow (queue length exceeding a finite number c) not necessarily within the same busy period has been obtained for the queueing systems M/G/l and GI/M/l using combinatorial arguments.
CONTROLLED SAMPLING WITH VARYING PROBABILITIES WITH AND WITHOUT REPLACEMENT
Authors: Avadhani M. S. , Sukhatme B. V.
Published: February 2008

Introduction and Summary

Goodman and Kish (1950) introduced the problem of controlled selection in the sense of decreasing the selection probability of nonpreferred combinations, such as, for example, combinations which present organisational difficulties involving additional cost, etc. The authors (Avadhani and Sukhatme (1965), Sukhatme and Avadhani (1965)) have evolved certain techniques of controlled selection which eliminate altogether some non‐preferred combinations and reduce the probability of selection of the remaining combinations, if any, to the minimum possible extent without deviating from the fundamental principles of random sampling. However, it is often felt convenient in practice to draw sampling units one after another from the population rather than combinations of units. But, at present no technique by which one can select the units one after another and at the same time reduce the probability of selection of non‐preferred units is available in literature.

In this paper we have suggested a solution to this problem which not only minimizes the selection probability of non‐preferred units (and of samples containing predominantly large numbers of nonpreferred units) but also provides more efficient estimators than the the usualprobability proportional to size(P.P.S) sampling scheme.
ESTIMATION OF THE PARAMETERS OF A NORMAL DISTRIBUTION WHEN THE MEAN IS RESTRICTED TO AN INTERVAL1
Authors: Heiny Robert L. , Siddiqui M. M.
Published: February 2008

Suppose it is known that the mean of a normal distribution is non‐negative. Naturally one will use the sample mean truncated at zero as an estimator of the distribution mean. In this paper the properties of such an estimator are investigated.
SAMPLING ON SEVERAL SUCCESSIVE OCCASIONS WITH EQUAL AND UNEQUAL PROBABILITIES AND WITHOUT REPLACEMENT1
Authors: Avadhani M. S. , Sukhatme B. V.
Published: February 2008

The applicability of the technique of controlled selection with equal probabilities proposed by the authors, Avadhani and Sukhatme (1965, 1968), and that of unequal probability sampling suggested by Raoet al.(1962) to sampling on several successive occasions is investigated in this paper. Appropriate recurrence formulae for the optimum replacement fraction and the corresponding weight are also derived.
A PROCEDURE FOR TESTING THE MEAN OF A NORMAL DISTRIBUTION1
Authors: Billard L.
Published: February 2008

A sequential procedure for comparing a null hypothesis concerning the unknown mean of a normal distribution whose variance is known, against a two‐sided alternative hypothesis is presented. This procedure incorporates additional safeguards as required by the practicing experimenter. Furthermore, approximate formulae for the O.C. function and the A.S.N. function are derived.
THE EFFECT OF SAMPLE STRUCTURE ON ANALYTICAL SURVEYS1,2
Authors: Brewer K. R. W. , Mellor R. W.
Published: February 2008

The core of this paper is a dialogue between “Harry”, an experienced survey statistician and “Fred”, a young mathematical statistician. They have contrasting approaches to the problem of estimating a regression relationship from a stratified sample, but after one or two red herrings are dragged out, both realize that the situation is not as simple as they had supposed. The role played by the probabilities of selection is a central issue. Estimation sampling for means, totals, and ratios is also considered, and seen to be a special case of the general analytical sampling synthesis they had already agreed upon.
STATISTICAL SOCIETY OF AUSTRALIA THE KNIBBS LECTURE FOR 1977: (SEPTEMBER 5th, 1977): FOUNDATIONS OF STATISTICAL INFERENCE: THE CASE FOR ECLECTICISM
Authors: Cox D. R.
Published: February 2008

First there is some general discussion of the place in statistics of work on the foundations of statistical inference. Three broad approaches, sampling theory, pure likelihood and Bayesian are distinguished and some general comments made on the advantages and limitations of each approach. It is concluded that all three have some role.
THE EFFICIENCY OF TIME SERIES ESTIMATORS FOR REPEATED SURVEYS
Authors: Jones Roger G.
Published: February 2008

The classical approach to the analysis of data from repeated surveys, based on Patterson (1950), has recently been extended by the work of Blight and Scott (1973) and Scott and Smith (1974), by assuming that a time series relationship exists between the population parameters at different times. The purpose of this paper is to compare the efficiencies of these three approaches by computing the mean square error (MSE) of the estimators of the current mean and of the change in mean on the last two occasions.
THE ANALYSIS OF TIME SERIES—THE TIME DOMAIN APPROACH1
Authors: NICHOLLS D. F.
Published: February 2008

This paper has three basic aims. The first of these is to give a concise outline of the analysis of time series, from an applied point of view, along the lines proposed by Box and Jenkins (1970). The second aim is to discuss a number of advances in this field since 1970, while the third is to discuss some of the more recent developments in the analysis of time series which are applicable in the physical and social sciences.
ODD MAN OUT—THE MEIXNER HYPERGEOMETRIC DISTRIBUTION
Authors: Lai C. D. , Vere‐Jones D.
Published: February 2008

Two open problems are described for the hyperbolic secant distribution, as a special case of the more general Meixner hypergeomet‐ric distribution. The first concerns the completeness of the family of functions sech θx, θ≥ 0. The second concerns the characterization of the class of canonical correlation sequences in bivariate distributions with marginals sech θx, sech θy.In both cases some partial results are put forward.
A MODIFICATION OF THE SEQUENTIAL PROBABILITY RATIO TEST FOR TESTING A NORMAL MEAN
Authors: Baruah H. K. , Bhattacharjee G. P.
Published: February 2008

A modification of the sequential probability ratio test is proposed in which Wald's parallel boundaries are broken at some preassigned point of the sample number axis and Anderson's converging boundaries are used prior to that. Read's partial sequential probability ratio test can be considered as a special case of the proposed procedure. As far as ‘the maximum average sample number reducing property is concerned, the procedure is as good as Anderson's modified sequential probability ratio test.
THE COVARIANCE ANALYSIS OF SOME CENSORED SURVIVAL DATA FROM A LARGE SCALE STUDY OF MELANOMA
Authors: McLachlan G. J. , Holt J. N.
Published: February 2008

Regression models of the proportional hazard type are applied to investigate the effect of certain covariates on the survival function of some cancer patients. The censored survival data for these patients were taken from a survey conducted by the Queensland Melanoma Project through which there are available histories of all malignant melanoma cases in Queensland for the period 1963–1969; follow‐up data on these cases were considered up to mid‐1976. One of the results of the survival analysis shows that the well‐known empirical observation that women have a better prognosis than men can be explained by the existence of a significant interaction between sex and the anatomical site of the lesion.
SOME SERIES OF EFFICIENCY BALANCED DESIGNS1
Authors: Dey A. , Singh M.
Published: February 2008

In this note, some series of efficiency balanced block designs have been obtained.
The Mean, Median, Mode Inequality and Skewness for a Class of Densities
Authors: MacGillivray H. L.
Published: February 2008

Recent work on the mean, median, mode inequality and skewness for unimodal continuous distributions is discussed with reference to the properties of totally positive kernels. These properties also give simple conditions which are sufficient for the inequality and which include the characterization of the Pearson family.
Large Sample Inference for Markovian Exponential Families with Application to Branching Processes with Immigration
Authors: Hudson Irene L.
Published: February 2008

This paper presents limit distributions for the score and likelihood‐ratio (L.R.) statistic for testing a composite hypothesis involving the mean of the offspring distribution of the Bienaymé‐Galton‐Watson branching process with immigration (BPWI) when the process is subcritical, critical or supercritical. The BPWI is shown to be a member of a certain Markovian exponential family.
Tables of Cyclic Incomplete Block Designs:r=k
Authors: Lamacraft Robin R. , CSIRO W. B. Hall
Published: February 2008

Initial blocks and efficiencies are given for cyclic incomplete block designs in the ranget= 10(1)60 andr=k= 3(1)10. The designs have been selected by search procedures using optimality criteria which maximize the efficiency factor.
A ROBUST TEST FOR MULTIPLE COMPARISONS OF CORRELATION COEFFICIENTS1
Authors: Eagleson G. K.
Published: February 2008

A limiting expression is derived for the tail of the distribution of the maximum of a set of product moment correlation coefficients. The technique used is quite general and may be applied to non‐normal observations as well as to rank correlation coefficients. The result obtained for the latter leads to a test procedure for multiple comparisons of these non‐parametric measures of dependence.
ANCILLARITY AND MINIMAL SUFFICIENCY
Authors: Gordon Ian
Published: February 2008

A discussion of ancillarity in multinomial distributions provides the context for an example which queries the priority of the Sufficiency Principle.
ASYMPTOTIC TESTS FOR GROWTH CURVE MODELS WITH AUTOREGRESSIVE ERRORS
Authors: Hudson Irene L.
Published: February 2008

This paper presents the limit distribution (as the number of time points increase) for the score vector of a growth curve model assuming both stationary and explosive autoregressive (A.R.) errors. Limit distributions of the score statistic and the likelihood‐ratio statistic for testing composite hypotheses about the regression parameters of several growth curves, when the autocorrelation parameters are treated as nuisance parameters, are presented.
THE ANALYSIS OF MULTISTRATA DESIGNED EXPERIMENTS WITH INCOMPLETE DATA
Authors: Houtman A. , Speed T.P. , Nielsen A. C.
Published: February 2008

summary

Building upon early work of E. A. Cornish we show that G. N. Wilkinson's version of Yates' approach to the analysis of designed experiments with a single error stratum carries over completely to designs with an arbitrary non‐singular covariance matrix, initially assumed known. We show that the equations, corrections, adjustments and algorithms all have their more general analogues and that these can be solved, computed or executed quite readily if the design has orthogonal block structure and satisfies Nelder's condition of general balance. The results are illustrated with a split‐plot and a simple (square) lattice design.
REDUCED RESIDUE CLASSES CYCLIC PBIB DESIGNS
Authors: Agrawal H. C. , Nair C. R.
Published: February 2008

summary

A new general class ofm‐class cyclic association scheme is defined forvtreatments, wherevis a composite number. A simple method of construction of PBIB designs having this association scheme using more than one initial block and some methods using only one initial block are proposed. A complete analysis of this type of PBIB designs is given. Also given is a list of 39 useful PBIB designs of this type havingv≤15 andr≤10 and having only three associate classes together with their efficiency factors for all types of comparisons and over all efficiency factors.
THE AUTOREGRESSIVE MOVING AVERAGE MODEL FOR SPATIAL ANALYSIS
Authors: Huang Jun S.
Published: February 2008

A two dimensional autoregressive moving average spatial model is used to analyse spatial interaction. Maximum likelihood estimates of the unknown parameters are derived as the solution of a system of nonlinear equations, and are shown to be best asymptotic normal. One important computational procedure is discussed. The argument is extended to the general regression model with autoregressive moving average residuals. Explicit computational formulae are given.
CANONICAL VARIATE ANALYSIS—A GENERAL MODEL FORMULATION
Authors: Campbell N. A.
Published: February 2008

A general model, specifying the population means as a function of the population canonical vectors, provides a natural basis for considering many aspects of canonical variate analysis. These aspects include: estimation for elliptical densities, and robust estimation; estimation of missing values; adequacy of hypothetical variables; regression in dummy variable space; and comparison of solutions.
THE CONTRIBUTION OF W. H. ARCHER TO VITAL STATISTICS IN THE COLONY OF VICTORIA
Authors: Hopper John L.
Published: February 2008

William Henry Archer, as Assistant Registrar General, was responsible for implementing the 1854 Registration Act in the colony of Victoria, and thereby helped establish the framework for official statistics in Australia. Eminently suitable for this role, having served his apprenticeship as an actuary and statistician in London prior to emigration in 1852, his career paralleled that of Dr. William Farr, the famous vital statistician. The greatest contribution Archer made to statistics in Australia was to put the lessons learnt by the statisticians of early Victorian England to advantage and place government statistical practices on a sound footing.

Archer had a special interest in infant and childhood mortality, then accounting for one‐half of all deaths in the new colony, and showed that a major factor was the extent of dysentery and diarrhoea during the warmer part of the year. Despite the high prevalence, Archer calculated the incidence of infant mortality to be less than in Europe at the time.

Had he established links with the medical profession or with persons in the Social sciences who could have appreciated the valuable information being collected in the new government records, as in England where the sanitary reformers made great use of data collected by Farr for their own ends, Archer could have had a far greater impact on the intellectual and medical life of Victoria. Instead he was deflected into an administrative career which ended prematurely for political and religious reasons.
ROW AND COLUMAN DESIGNS WITH CONTIGUOUS REPLICATES
Authors: Williams E. R.
Published: February 2008

A method is given for constructing row and column designs for situations where replicates are contiguous. Designs of this type are needed in cotton variety trials. A table of generating arrays is given from which a series of resolvable designs can be constructed; these designs are called latinized α‐designs. Some results from cotton variety trials are presented.
The Multiple Outlier Problem in Time Series Analysis
Authors: Schmid Wolfgang
Published: February 2008

In this paper we consider the multiple outlier problem in time series analysis. The underlying undisturbed time series is assumed to be an autoregressive process. The location of the suspicious values is supposed to be known. We introduce conditional least squares estimators for the parameters. The estimates are shown to be strongly consistent. Using similar arguments as in the theory of linear models, we get a test statistic for the general linear hypothesis. Its asymptotic distribution is derived.
A Permutation Test for Planar Regression
Authors: Collins Mark F.
Published: February 2008

Oja (1987) presents some distribution‐free tests applicable in the presence of covariates when treatment values are randomly assigned. The formulas and calculations are cumbersome, however, and implementation of the tests relies on using a x2 approximation to the exact null distribution. In this paper a re‐formulation of his test statistic is given which has the advantages of ease of calculation, explicit formulas for permutation moments, and allowing a Beta distribution to be fitted to the exact null distribution.
RANDOMISED RESPONSE VS. DIRECT QUESTIONING: ESTIMATING THE PREVALENCE OF ALCOHOL RELATED PROBLEMS IN A FIELD SURVEY
Authors: Duffy John C. , Waterton Jennifer J.
Published: February 2008

Fifteen hundred adults selected for a population survey from the City of Edinburgh Electoral Registers by probability sampling were allocated to randomised response interview or direct interview at random. These alternative interviewing strategies were adopted for two questions relating to attributes which might be considered stigmatising. There were no significant differences in reporting between the two methods either at aggregate or at subgroup level. The apparent failure of the randomised response method to increase estimates of the proportions with the attributes hypothesised indicates either that traditional methods are satisfactory for the collection of this sensitive information, or that randomised response was not an acceptable alternative.
SOME ISSUES ARISING FROM THE ANALYSIS OF 2×2 CONTINGENCY TABLES
Authors: Lloyd C.J.
Published: February 2008

We review the 40 year old controversy over the correct analysis of 2×2 tables. It is argued that conditioning on all marginal totals is appropriate by examining the likelihood based on these margins and secondly by comparing conditional and unconditional evaluations of certain specific outcomes. Several foundational issues which naturally arise are also discussed.
APPLICATIONS AND EXTENSIONS OF BASU'S RESULTS ON MAXIMAL ANCILLARITY
Authors: Lloyd Christopher J.
Published: February 2008

Maximality of ancillaries is important in both conditional inference without nuisance parameters and marginal inference with nuisance parameters. We extend results of Basu (1959) to the more classical former case and discuss the different nature of ancillaries in these two contexts. We apply the results to a general ancillary independent of a sufficient statistic. Finally, we discuss difficulties in finding necessary conditions for maximality.
UNEMPLOYMENT DURATION: MODELLING AND ESTIMATION WITH PARTICULAR REFERENCE TO THE AUSTRALIAN LONGITUDINAL SURVEY
Authors: James Ian R.
Published: February 2008

Some of the issues in the analysis of durations of unemployment spells are considered, including, in particular, notions of duration dependence and the effect of the sampling scheme on the correct incorporation of incomplete or censored spells. Attention is restricted to analysis of spells overlapping a particular time point, and consideration is given to the situations where one has data only on the backward recurrence times, and where additional follow‐up information on the forward recurrence times is also available. In the former case a quasi‐likelihood approach is suggested as a possible alternative to full parametric modelling under some special conditions, while in the latter case arguments are forwarded in favour of analyses based on the conditional distribution of the forward recurrence times given the backward recurrence times. The methods are briefly illustrated using samples extracted from the Australian Longitudinal Survey.
A BETA‐OPTIMAL TEST OF THE EQUICORRELATION COEFFICIENT
Authors: Bhatti Muhammad I. , King Maxwell L.
Published: February 2008

This paper considers the problem of testing for nonzero values of the equicorrelation coefficient of a standard symmetric multivariate normal distribution. Recently, SenGupta (1987) proposed a locally best test. We construct a beta‐optimal test and present selected one and five percent critical values. An empirical power comparison of SenGupta's test with two versions of the beta‐optimal test and the power envelope shows the relative strengths of the three tests. It also allows us to assess and confirm Efron's (1975) rule of when to question the use of a locally best test, at least for this testing problem. On the basis of these results, we argue that the two beta‐optimal tests can be considered as approximately uniformly most powerful tests, at least at the five percent significance level.
EXPERIMENTAL DESIGN FOR CONTINUOUS PROCESSES
Authors: Saunders Ian W. , Eccleston John A.
Published: February 2008

Measurements taken on a continuous process (e.g. production of chemicals, ore processing, steel production) often exhibit autocorrelation. Such correlation between successive measurements can be avoided only by taking measurements at widely separated times, but this delays the results. We discuss the impact of this correlation on experimental designs which for a continuous process must include the sequence in which treatment combinations are applied and the spacing between samples. The variogram of the process is a convenient Summary of the correlation. Formulae for the variance of the mean of measurements taken on a continuous process and of contrasts calculated from such measurements are simple expressions in terms of the variogram. These formulae allow a simple approach to experimental designs that avoid unnecessary delays.
INCOMPLETE DATA IN GENERALIZED LINEAR MODELS WITH CONTINUOUS COVARIATES
Authors: Brahim Joseph G. , Weisberg Sanford
Published: February 2008

This paper proposes a method for estimating the parameters in a generalized linear model with missing covariates. The missing covariates are assumed to come from a continuous distribution, and are assumed to be missing at random. In particular, Gaussian quadrature methods are used on the E‐step of the EM algorithm, leading to an approximate EM algorithm. The parameters are then estimated using the weighted EM procedure given in Ibrahim (1990). This approximate EM procedure leads to approximate maximum likelihood estimates, whose standard errors and asymptotic properties are given. The proposed procedure is illustrated on a data set.
NONLINEAR REGRESSION MODELLING AND TIME DEPENDENT COVARLATES IN REPEATED MEASURES EXPERIMENTS
Authors: Cullis B.R. , Verbyla A.P.
Published: February 2008

The procedure of Verbyla & Cullis (1990) is extended to cater for the analysis of repeated measures data in which either non‐linear modelling of the treatment contrasts is required and or there are time dependent covariates. These extensions are illustrated via two agricultural data sets.
ON THE ROBUST ANALYSIS OF VARIANCE COMPONENTS MODELS FOR PEDIGREE DATA
Authors: Huggins R.M.
Published: February 2008

Quantitative traits measured over pedigrees of individuals may be analysed using maximum likelihood estimation, assuming that the trait has a multivariate normal distribution. This approach is often used in the analysis of mixed linear models. In this paper a robust version of the log likelihood for multivariate normal data is used to construct M‐estimators which are resistant to contamination by outliers. The robust estimators are found using a minimisation routine which retains the flexible parameterisations of the multivariate normal approach. Asymptotic properties of the estimators are derived, computation of the estimates and their use in outlier detection tests are discussed, and a small simulation study is conducted.
ESTIMATION OF THE CONCENTRATION PARAMETERS OF THE FISHER MATRIX DISTRIBUTION ON 50(3) AND THE BINGHAM DISTRIBUTION ONSq,q≥ 2
Authors: Wood Andrew T.A.
Published: February 2008

Two procedures are considered for estimating the concentration parameters of the Fisher matrix distribution for rotations or orientations in three dimensions. The first is maximum likelihood. The use of a convenient 1‐dimensional integral representation of the normalising constant, which greatly simplifies the computation, is suggested. The second approach exploits the equivalence of the Fisher distribution for rotations in three dimensions, and the Bingham distribution for axes in four dimensions. We describe a pseudo likelihood procedure which works for the Bingham distribution in any dimension. This alternative approach does not require numerical integration. Results on the asymptotic efficiency of the pseudo likelihood estimator relative to the maximum likelihood estimator are given, and the two estimators are compared in the analysis of a well‐known vectorcardiography dataset.
PARAMETER ESTIMATION FOR LOW‐ORDER AUTO‐REGRESSIVE MODELS WITH MISSING VALUES
Authors: Segal Mark R. , Rosner Bernard , Liou Albert G.S. , Schouten Jan P.
Published: February 2008

Longitudinal data analysis in epidemiological settings is complicated by large multiplicities of short time series and the occurrence of missing observations. To handle such difficulties Rosner & Muñoz (1988) developed a weighted non‐linear least squares algorithm for estimating parameters for first‐order autoregressive (AR1) processes with time‐varying covariates. This method proved efficient when compared to complete case procedures. Here that work is extended by (1) introducing a different estimation procedure based on the EM algorithm, and (2) formulating estimation techniques for second‐order autoregressive models. The second development is important because some of the intended areas of application (adult pulmonary function decline, childhood blood pressure) have autocorrelation functions which decay more slowly than the geometric rate imposed by an AR1 model. Simulation studies are used to compare the three methodologies (non‐linear, EM based and complete case) with respect to bias, efficiency and coverage both in the presence and in the absence of time‐varying covariates. Differing degrees and mechanisms of missingness are examined. Preliminary results indicate the non‐linear approach to be the method of choice: it has high efficiency and is easily implemented. An illustrative example concerning pulmonary function decline in the Netherlands is analyzed using this method.
ON THE INDEPENDENCE OF THE SAMPLE MEAN AND TRANSLATION‐INVARIANT STATISTICS FOR MATRIX NORMAL DISTRIBUTIONS
Authors: M.YOUNG DEAN , ODELL PATRICK L. , SEAMAN JOHN W.
Published: February 2008

We present an explicit characterization of the joint dependency structure of ann×pmatrix normal random matrix such that the p‐dimensional sample mean vector is independent of all translation invariant statistics.
A LIKELIHOOD APPROACH TO SCALING EXAMINATION MARKS
Authors: Biggins J.D. , Yue K.K.
Published: February 2008

One of the common approaches to the problem of scaling and combining examination marks has its roots in the least squares tradition. In this framework, examiners' preconceptions about the transformations must be dealt with in an adhocway. This paper investigates another, likelihood‐based, approach which allows preconceptions to be handled by standard Bayesian techniques. The likelihood and least squares approaches are not directly parallel (essentially because a Jacobian must be included in the likelihood). Nonetheless, the device of introducing fictitious candidates to deal with prior beliefs in the least squares set‐up can be understood in a Bayesian sense.
THE ROBUSTNESS OF BINARY AND NON‐BINARY BALANCED NESTED ROW‐COLUMN DESIGNS UNDER THE UNAVAILABILITY OF BLOCKS: A COMPARISON
Authors: Uddin Nizam , Whittinghill Dexter C.
Published: February 2008

In cases where both exist, the balanced, binary nested row‐column designs are known to be inferior to a class of balanced non‐binary designs. However, if it is possible for blocks of observations to become unavailable after an experiment has commenced, a binary nested row‐column design may possibly be better than a non‐binary one. This paper investigates the robustness of binary and non‐binary variance‐balanced nested row‐column designs to the unavailability of one or more blocks of observations. Robustness is measured through the C‐matrices of the designs resulting from removing blocks, using optimality criteria such as A‐, D‐, E‐ and MV‐optimality.
A NOTE ON COMPETING VARIANCE ESTIMATORS IN RANDOMISED RESPONSE SURVEYS
Authors: Chaudhuri Arijit , Maiti Tapabrata , Roy Debesh
Published: February 2008

When gathering randomised rather than direct responses on a variable of interest relating to sensitive issues, one may use a modified version of the well‐known generalised regression predictor of a finite population total. To construct confidence intervals, this paper proposes four alternative variance estimators – modifications to those usable with direct responses – and examines their relative efficiencies through simulations from simple super‐population models.
DETERMINATION OF DOMAINS OF ATTRACTION BASED ON A SEQUENCE OF MAXIMA
Authors: Wang J.Z. , Cooke P. , Li S.
Published: February 2008

Suppose that the maximum of a random sample from a distributionF(x) may be obtained in each ofkequally spaced observation periods. This paper proposes a test to determine the domain of attraction ofF(x), and investigates the properties when the sample size is very large and perhaps unknown andkis fixed and small. The test statistic is a function of the spacings between the order statistics based on the sequence of maxima and is suggested by reference to one studied previously when inference was based on the largestkobservations of a random sample. A Monte Carlo study shows that the proposed test is more powerful than its main competitor. The test is illustrated by two examples.
ON THE NUMBER OF RECORDS NEAR THE MAXIMUM
Authors: Pakes Anthony G. , Steutel Fred W.
Published: February 2008

summary

Recent work has considered properties of the number of observationsXj, independently drawn from a discrete law, which equal the sample maximumX(n)The natural analogue for continuous laws is the numberKn(a) of observations in the interval (X(n)–a,X(n)], wherea> 0. This paper derives general expressions for the law, first moment, and probability generating function ofKn(a), mentioning examples where evaluations can be given. It seeks limit laws forn→ and finds a central limit result whenais fixed and the population law has a finite right extremity. Whenever the population law is attracted to an extremal law, a limit theorem can be found by lettingadepend onnin an appropriate manner; thus the limit law is geometric when the extremal law is the Gumbel type. With these results, the paper obtains limit laws for ‘top end’ spacingsX(n)‐X(n‐j)withjfixed.
TIGHT UPPER CONFIDENCE LIMITS FROM DISCRETE DATA
Authors: Kabaila Paul , Lloyd Chris J.
Published: February 2008

summary

Consider the problem of finding an upper 1 –α confidence limit for a scalar parameter of interest ø in the presence of a nuisance parameter vector θ when the data are discrete. Approximate upper limitsTmay be found by approximating the relevant unknown finite sample distribution by its limiting distribution. Such approximate upper limits typically have coverage probabilities below, sometimes far below, 1 –α for certain values of (θ, ø). This paper remedies that defect by shifting the possible valuestofTso that they are as small as possible subject both to the minimum coverage probability being greater than or equal to 1 –α, and to the shifted values being in the same order as the unshiftedts. The resulting upper limits are called ‘tight’. Under very weak and easily checked regularity conditions, a formula is developed for the tight upper limits.
ERROR BOUNDS FOR CALCULATION OF THE GITTINS INDICES
Authors: Wang You‐Gan
Published: February 2008

summary

For a wide class of semi‐Markov decision processes the optimal policies are expressible in terms of the Gittins indices, which have been found useful in sequential clinical trials and pharmaceutical research planning. In general, the indices can be approximated via calibration based on dynamic programming of finite horizon. This paper provides some results on the accuracy of such approximations, and, in particular, gives the error bounds for some well known processes (Bernoulli reward processes, normal reward processes and exponential target processes).
THE CUBE OF A LOGISTIC DISTRIBUTION IS INDETERMINATE
Authors: LIN G.D. , HUANG J.S.
Published: February 2008

It is known that most distributions are uniquely determined by their moments. Exceptions exist, but are believed to be rare among those we encounter in everyday life applications. We add one more to the rare collection, and suggest that indeterminate distributions are perhaps more prevalent than is commonly perceived.
A Polyocular Framework for Research on Multifunctional Farming and Rural Development
Authors: Noe Egon , Alrøe Hugo Fjelsted , Langvad Anne Mette S.
Published: February 2008

The paradox of multifunctionality is that, on the one hand, the specialised functionalities of agriculture arise only because of the functional differentiation of social systems and scientific disciplines and, on the other hand, multifunctionality can enter only as a way to mediate between conflicts, interests and fragmented knowledge when different functions and observations of functions combine. The aim of this article is to contribute to a theoretical and methodological platform for multidisciplinary research on multifunctional farming. With the notions of polyocular cognition and polyocular communication we introduce a second order, interdisciplinary communication process that can meet the challenge of creating a shared view on multifunctional farming. Polyocular communication must be based on rules other than the rules of the disciplines involved. Whereas disciplinary communication is about providing consistent, efficient and precise knowledge in the context of a sharply delimited research world, polyocular communication is about extending a multidimensional space of understanding.
Exploring Farmers' Cultural Resistance to Voluntary Agri‐environmental Schemes
Authors: Burton Rob. J.F. , Kuczera Carmen , Schwarz Gerald
Published: February 2008

Studies throughout Europe have suggested that voluntary agri‐environmental programmes often engender very little change in attitudes towards productivist agriculture among conventional farming communities. This study examines why this may be so, using case studies from Hessen, Germany and Aberdeenshire, Scotland. By constructing a conceptual framework based on Bourdieu's notions of capital we explore how farming activities are able to generate symbolic capital, and compare this with the symbolic value of conservation work. We find that voluntary agri‐environmental work returns little symbolic capital to farmers as, by prescribing management practices and designating specific areas for agri‐environmental work, such schemes fail to allow farmers to develop or demonstrate skilled role performance – thus inhibiting the development of embodied cultural capital. We conclude by suggesting that entrepreneurial production‐target based agri‐environmental schemes may be ultimately more effective in changing long‐term behaviour.
Effect of food on the antiviral activity of didanosine enteric‐coated capsules: a pilot comparative study*
Authors: Hernández‐Novoa B , Antela A , Gutiérrez C , Pérez‐Molina JA , Pérez‐Elías MJ , Dronda F , Moreno A , Casado JL , Page C , Pumares M , Galán JC , Moreno S
Published: February 2008

Objectives

To determine the effect of food on the antiviral activity of enteric‐coated (EC) capsules of didanosine (ddI).

Methods

We conducted a pilot, randomized, open‐label study of 28‐day ddI‐EC capsules monotherapy‐administered in a fasted state (group 1, n=11) or with food (group 2, n=10) to treatment‐naïve chronically HIV‐1‐infected individuals. To assess the antiviral efficacy, HIV‐1 RNA was determined at baseline, day 3, day 7 and weekly thereafter. The area under the HIV‐1 RNA curve minus baseline weighted by time (AUCMB/day) was calculated.

Results

Mean baseline HIV‐1 RNA was 4.2 log10 copies/mL in group 1 and 3.8 log10 copies/mL in group 2. After 28 days, the mean HIV‐1 RNA reduction was 0.99 log10 copies/mL [95% confidence interval (CI) 0.45–1.53] for group 1 and 0.89 log10 copies/mL (95% CI 0.38–1.40) for group 2. AUCMB/day values were 0.775 log10 copies/mL (95% CI 0.33–1.22) and 0.774 log10 copies/mL (95% CI 0.48–1.07), respectively, showing no difference in the rate of decrease of HIV‐1 RNA (P=0.995). Mean ddI plasma levels at day 28 were 0.0234 mg/L for group 1 and 0.0227 mg/L for group 2 (P=0.96).

Conclusions

In this pilot study, the administration of food did not have any significant effect on the antiviral activity of ddI‐EC capsules.
An audit of viral load in one clinical population to describe features of viraemic patients on antiretroviral therapy
Authors: Madge S , Smith CJ , Lampe F , Sabin CA , Youle M , Johnson MA , Phillips AN
Published: February 2008

Objectives

To assess the prevalence of an undetectable viral load (VL) (<50 HIV‐1 RNA copies/mL) in a clinical population and to identify those viraemic and at risk of failing antiretroviral therapy (ART).

Methods

An audit of a complete clinical population on 1 January 2005 via a clinical database and clinical note review.

Results

On 1 January 2005, 1910 patients were under care; 1229/1332 (92%) of those exposed to ART for >16 weeks had a VL of <50 copies/mL. We examined 49/56 case notes of viraemic patients to identify explanations for viraemia. Common reasons included previous initial mono‐ or dual therapy, adherence problems, more advanced HIV disease, concomitant medications, physical and mental health issues and being less well linked into the service. A review of these patients' current status on 1 April 2007 showed that six of the 49 had since died. However, of those still alive, 20 (47%) had a VL <500 copies/mL.

Conclusions

The proportion of patients on ART with detectable viraemia is low in current clinical practice. New drugs may help those who are failing because of resistance. However, there is a small minority of patients who, for various reasons, appear unable to maintain sufficient adherence to ART.
Emergency perception and other variables associated with extra‐hospital delay in stroke patients in the Maresme region (Spain)
Authors: Palomeras E. , Fossas P. , Quintana M. , Monteis R. , Sebastián M. , Fábregas C. , Ciurana A. , Ribó M. , Cano A. , Sanz P. , Floriach M. , Álvarez‐Sabín J.
Published: February 2008

Delay in arrival to the emergency room (ER) may negatively influence outcome of stroke patients. We aim to analyze factors that influence extra‐hospital delay in stroke patients. Two hundred and ninety‐two consecutive stroke patients admitted in the ER were prospectively studied. Analysis was made to identify variables associated with <1‐ and <3 h delays from onset. About 18.8% of patients arrived before 1 h and 57.5% before 3 h. Factors independently associated with <3 h delay were decision to go immediately to ER (OR = 8.17; 95% IC = 4.47–18.8), ambulance transportation (OR = 2.35; 1.36–4.05) and total anterior circulation syndrome (TACS) (OR = 3.74; 1.51–9.24). History of >1 vascular risk factor was associated with a greater delay (OR = 0.47; 0.26–0.86). Factors associated with a <1 h delay were: (i) immediate decision to attend the ER (OR = 3.55; 1.85–6.81), (ii) stroke on Sunday (OR = 3.46; 1.56–7.66), (iii) aphasia (OR = 2.41; 1.23–4.74), (iv) absence of stairs at home (OR = 0.37; 0.17–0.81) and (v) absence of diabetes mellitus (OR = 0.42; 0.20–0.88). In our area, nearly 60% of stroke patients arrive to ER before 3 h from onset. Immediate decision to attend the ER has the strongest association with a short delay. Patients with TACS arrived mainly before 3 h and those with isolated aphasia arrived before 1 h. Patients with vascular risk factors attended the hospital later. Ambulance transportation is associated with <3 h delay, but not with <1 h.
Exon Deletion in the Non‐catalytic Domain of eIF2Bɛ Due to a Splice Site Mutation Leads to Infantile Forms of CACH/VWM with Severe Decrease of eIF2B GEF Activity
Authors: Horzinski L. , Gonthier C. , Rodriguez D. , Scherer C. , Boespflug‐Tanguy O. , Fogli A.
Published: February 2008

The CACH/VWM syndrome is an autosomal recessive leukodystrophy characterized by a broad spectrum of clinical presentations and by diffuse cavitary degeneration of the white matter on MRI. Mutations responsible for this disorder are missense or frameshift mutations occurring in the five genes (EIF2B1‐5) that encode the translation eukaryotic initiation factor eIF2B. We found that a patient with infantile CACH/VWM carries a mutation in the acceptor splice site of EIF2B5 exon 6. In lymphoblastoid cells of the patient, we detected an abnormal EIF2B5 transcript in which exon 6 was absent, however, the predicted protein product lacking part of the non‐catalytic domain encoded by exon 6 was not detected. The eIF2B GEF activity was severely decreased. These data support the importance of the non‐catalytic domain of the eIF2Bɛ subunit in the eIF2B complex formation and activity.
Migration Waves to the Baltic Sea Region
Authors: Lappalainen T. , Laitinen V. , Salmela E. , Andersen P. , Huoponen K. , Savontaus M.‐L. , Lahermo P.
Published: February 2008

In this study, the population history of the Baltic Sea region, known to be affected by a variety of migrations and genetic barriers, was analyzed using both mitochondrial DNA and Y‐chromosomal data. Over 1200 samples from Finland, Sweden, Karelia, Estonia, Setoland, Latvia and Lithuania were genotyped for 18 Y‐chromosomal biallelic polymorphisms and 9 STRs, in addition to analyzing 17 coding region polymorphisms and the HVS1 region from the mtDNA. It was shown that the populations surrounding the Baltic Sea are genetically similar, which suggests that it has been an important route not only for cultural transmission but also for population migration. However, many of the migrations affecting the area from Central Europe, the Volga‐Ural region and from Slavic populations have had a quantitatively different impact on the populations, and, furthermore, the effects of genetic drift have increased the differences between populations especially in the north. The possible explanations for the high frequencies of several haplogroups with an origin in the Iberian refugia (H1, U5b, I1a) are also discussed.
Two conventional protein kinase C isoforms, α and βI, are involved in the ATP‐induced activation of volume‐regulated anion channel and glutamate release in cultured astrocytes
Authors: Rudkouskaya Alena , Chernoguz Artur , Haskew‐Layton Renée E. , Mongin Alexander A.
Published: February 2008

Volume‐regulated anion channels (VRACs) are activated by cell swelling and are permeable to inorganic and small organic anions, including the excitatory amino acids glutamate and aspartate. In astrocytes, ATP potently enhances VRAC activity and glutamate release via a P2Y receptor‐dependent mechanism. Our previous pharmacological study identified protein kinase C (PKC) as a major signaling enzyme in VRAC regulation by ATP. However, conflicting results obtained with potent PKC blockers prompted us to re‐evaluate the involvement of PKC in regulation of astrocytic VRACs by using small interfering RNA (siRNA) and pharmacological inhibitors that selectively target individual PKC isoforms. In primary rat astrocyte cultures, application of hypoosmotic medium (30% reduction in osmolarity) and 20 μM ATP synergistically increased the release of excitatory amino acids, measured with a non‐metabolized analog ofl‐glutamate,d‐[3H]aspartate. Both Go6976, the selective inhibitor of Ca2+‐sensitive PKCα, βI/II, and γ, and MP‐20‐28, a cell permeable pseudosubstrate inhibitory peptide of PKCα and βI/II, reduced the effects of ATP ond‐[3H]aspartate release by ∼45–55%. Similar results were obtained with a mixture of siRNAs targeting rat PKCα and βI. Surprisingly, down‐regulation of individual α and βI PKC isozymes by siRNA was completely ineffective. These data suggest that ATP regulates VRAC activity and volume‐sensitive excitatory amino acid release via cooperative activation of PKCα and βI.