bluuebunny/crossref_metadata_2025 huggingface dataset:
Subset Selection Procedures for Randomized Designs
Authors: Dourleijn C. Johan , Driessen Stefan G. A. J.
Published: May 2007

Starting from the principle that there exists a randomization procedure that assigns treatments to experimental units, four subset selection rules for the problem of selecting the best treatment from a set of different treatments are proposed. Two of these are extensions of already existing subset selection procedures, which were defined for unbalanced designs, and need a separate selection constant for each individual treatment. The other two rules proposed are new and need only one selection constant for all treatments. The various procedures are compared, and illustrated by application to a plant breeding variety trial.
Assessment of Data Quality: Errors of Measurement and Errors of Process
Authors: Arndt Stephan , Woolson Robert W.
Published: May 2007

As projects progress from pilot studies with few simple variables and small samples, the research process as a whole becomes qualitatively more complex and subject to an array of contamination by errors and mistakes. Data usually undergo a series of manipulations (e.g., recording, computer entry, transmission) prior to final statistical analysis. The process, then, consists of numerous operations only ending with eventual statistical analysis and write‐up. We present a means of estimating the impact of process error in the same terms as psychometric reliability and discuss the implications for reducing the impact of errors on overall data quality.
Design and Analysis of Field Experiments Incorporating Local and Remote Effects of Treatments
Authors: Gill P. S.
Published: May 2007

Design and analysis of field experiments in the presence of local and remote treatment effects are considered. The design criteria are optimality and balance for estimating local and remote effects. A nonlinear model, where remote effects are assumed to be proportional to the local effects, has been discussed.
Use of Probability Weighted Moments in the Analysis of Means
Authors: Muhammad F. , Ahmad S. , Abiodullah M.
Published: May 2007

In the analysis of means the estimate of σ is usually calculated using range. In this study it is proposed that the linear estimate of σ based on probability weighted moments should be used. A simulation study based on 1000 values suggested that the linear estimate of σ using probability weighted moments is more close to the original value. In the simulations different distributions such as normal, t, Cauchy and exponential were assumed.
Estimation of Exponential Parameters in the Presence of Outliers
Authors: Jeevanand E. S. , Nair N. Unnikrishnan
Published: May 2007

In the present paper we discuss the estimation of the parameter and survival function of an exponential population. It is assumed that the sample based on which the estimation is done, containskoutliers that are also exponentially distributed with parameter, a constant multiple of that of the original distribution.
On Presenting Results of Statistical Analyses in Scientific Journals
Authors: Finney David J.
Published: May 2007

In many biological and other scientific journals, a reader's understanding of a paper to the argument of which statistical methods and analyses are important is often impeded by confusions of terminology and ambiguities of symbols. This is not solely because statistics is a difficult subject for biologists! If an editor were to formulate and make known a code of statistical symbols, abbreviations, and technical terms that in his journal will be regarded as part of the normal language of science, an author could use these without need for explanation each time. Every author would remain free to depart from the code, provided that he defined clearly his own usages. Such a policy, supported by the journal's referees, would do much to remove the frequent necessity for a reader to guess an author's meaning. Similarly considerations apply to the use of statistical software packages, where there is an evident need for an author to declare what software (if any) he has used, in much the same way as, by established custom, he will carefully specify his experimental materials and methods where these in any respect differ from the obvious.

The present paper is written to stimulate constructive debate, and in no way to dogmatize on the merits or faults of particular statistical methods. Its underlying spirit is that the author of a scientific communication has a duty to describe the making of his observations, the conduct of his computations, and the performance of his computations with a clarity that would permit their repetition by another scientist who has access to the appropriate facilities and resources.
Confidence Intervals on the Total Variance in an Unbalanced Two‐fold Nested Design
Authors: Hernandez Ramon P. , Burdick Richard K.
Published: May 2007

Confidence intervals on the total variance in an unbalanced random two‐fold nested design are constructed and compared. Computer simulation indicates the proposed intervals provide confidence coefficients that are generally close to the stated level.
Pooling Strategies for Screening Blood in Areas with Low Prevalence of HIV
Authors: Lan Shou‐Jen , Hsieh Chung‐Cheng , Yen Yea‐Yin
Published: May 2007

Human immunodeficiency virus (HIV) infection has serious consequences and must be kept out of blood supplies. Screening to ensure the safety of blood supplies is associated with a very high cost. The idea of pooling test samples to obtain significant savings was first suggested in 1943. Recently pooling sera has gained wider interest both as a means to determine the HIV seroprevalence rate in general populations and to weed out all HIV‐positive units in blood supplies. We describe a simple method for detecting seropositive samples in mass screening. This method determines the pooling size based on the estimated prevalence rate. Although several repooling stages are allowed, these will be kept to a minimum since the more stages that are required, the greater chance for human and technical errors. The criteria to end pooling are based on both the savings rate and the relative cost between the preparation and the actual test. Two examples illustrate the applications of this method in determining the number of samples to be pooled in successive stages and the resulting savings rate.
Consensus Principal Components
Authors: Lefkovitch L. P.
Published: May 2007

From the polar forms of the principal components corresponding with each of a set of covariance (or correlation) matrices, a linear combination based on their inner products is defined as the polar form of the consensus. The corresponding eigenvectors form an orthogonal matrix which rotates each of the covariance matrices to approximate diagonal form. From the norms of the polar forms, these eigenvectors can be used to estimate a common covariance matrix. These procedures are illustrated by a numerical example.
Unbiased Estimation of Odds Ratio by Using Negative Binomial Plans
Authors: Roberts Charles Dewitt
Published: May 2007

The use of the negative binomial distribution in both the numerator and denominator in prospective studies leads to an unbiased estimate of the odds ratio and an exact expression for its variance. Sample sizes that minimize the variance of odds ratio estimates are specified. The variance of the odds ratio estimate is shown to be close to the Cramér‐Rao lower bound.
Testing the Equality of Dependent Variances
Authors: Modarres Reza
Published: May 2007

The likelihood ratio test for testing equality of vgE;2 correlated variables is developed. In general, evaluation of the test statistic involves the iterative optimization of a likelihood function with 1 + v(v – 1)/2 parameters. The explicit form of the test statistic is derived in the bivariate case, and an iterative algorithm for determining the maximum likelihood estimates is suggested. A limited Monte Carlo study determines the behavior of the proposed procedure under the null hypothesis and variety of parameter values.
Application of Partially Balanced Block Designs to Factorial Experiments
Authors: Brzeskwiniewicz Henryk
Published: May 2007

In this paper we present partially balanced block designs with Fp and Cp association schemes. These designs play a great role in the experimental theory since they can be applied to factorial experiments. A particular stress is put on the formulation of association schemes p and Cp, presentation of exemplary constructions of these designs and their analysis of variance. The presented considerations are abundantly illustrated with examples.
Markov Chain Model and its Application to Study Survival Distribution
Authors: Jain R. K.
Published: May 2007

In this paper, a canonical representation of transition probability matrix under Markov assumption is proposed as a mathematical model to study the survival distribution. A numerical example is used to illustrate the computational techniques.
On Testing for Non‐Additivity in Factorial Experiments
Authors: Zafar‐Yab Mohammad
Published: May 2007

In analysis of variance the assumption of non‐additivity has more serious consequences on the interpretation of results than the assumptions of non‐normality or non‐homogeneity of variances. Tukey (1949, 1955) suggested a procedure for separating out a single degree of freedom for non‐additivity for two factor and multi‐factor experiments, respectively. In multifactor experiments Tukey's procedure does not indicate which combinations of the factors contribute to non‐additivity. In this paper a procedure is proposed which separates out a sum of squares with a single degree of freedom from each of the 2P−P−1 interactions in aP‐factor experiment.
Parameter Estimation in Systematic Sampling
Authors: Schneeberger Hans
Published: May 2007

First it is shown that an estimate of the variance of the sample‐mean in systematic sampling from a non‐autocorrelated population with linear trend, which is published in textbooks, isn't a suitable estimate: It is biased and not dependent on the essential parameter, the slope of the linear trend.

In section 2 an unbiased estimate of the variance is given. As estimate of the sample‐mean we take the same as usually used in literature.

In section 3 a centric estimate of the sample‐mean is introduced, which takes into consideration the slope of the trendline. It is shown that this estimate is unbiased; an unbiased estimate of its variance is given.
Fecundibility and Social Development in China: Changes in the Distribution of the First Conception Interval
Authors: Sturm Roland , Zhang Junsen
Published: May 2007

While it is typically assumed that the hazard of conception of a susceptible woman is either constant or decreasing, we find evidence that the hazard is increasing with the duration of marriage in China. This positive duration dependence may reflect the effects of spouses getting accustomed to each other and may exist in other “traditional” societies. We also explore whether changing customs may lead to changes in the duration dependence across cohorts or provinces. We find a small decline in the positive duration dependence over time in one province, which might be interpreted as a diminishing “late honeymoon”‐effect. Somewhat stronger is the difference between the more rural provinces Hebei and Shaanxi and the urbanized municipality of Shanghai.
Tree‐Structured Exponential Regression Modeling
Authors: Ahn Hongshik
Published: May 2007

A method for fitting piecewise exponential regression models to censored survival data is described. Stratification is performed recursively, using a combination of statistical tests and residual analysis. The splitting criterion employed in cross‐validation is the average squared error of the residuals. The bootstrap is employed to keep the probability of a type I error (the error of discovering two or more strata when there is only one) of the method close to a predetermined value. The proposed method can thus also serve as a formal goodness‐of‐fit test for the exponential regression model. Real and simulated data are used for illustration.
Recursive Residuals for Multivariate Field Processes
Authors: Tobing H. , McGilchrist C. A.
Published: May 2007

Vector recursive residuals are developed for multivariate regression models on a field. A vector response variable is observed at points on a rectangular grid, together with regression variables measured at the same points. Neighbouring values of the response vector may be correlated and simple models are considered using a direct product structure for the variance matrix. Subsequent to obtaining vector recursive residuals principal component analysis is applied to obtain an evaluation of any changes that may be occurring in the regression relationship over the field. The method is then applied to the problem of detecting zones of bush fire damage and recovery from LANDSAT data.
Analysis of Variety Trials in the Presence of Non‐Random Time Effect
Authors: Odulaja A. , Afonja B. , Bamiduro T. A.
Published: May 2007

The assumption of random year effect in the analysis of variety trials data over locations and years clearly contradicts the practice of conducting the trials over only a few consecutive years. A method of analysis of such trials which assumes that the year‐dependent effects are serially correlated is proposed in this paper to cater for the non‐randomness in the selection of years of the experiments. A simple autoregressive model was assumed for the serial relationship. A reduction in the variance estimate of the difference between two variety means was obtained using this method.
Non‐Standard Log‐Linear Models for Orthogonal Prediction Configural Frequency Analysis
Authors: von Eye Alexander , Rovine Michael J.
Published: May 2007

The paper discusses LAUTSCH, LIENERT. and VON EYE'S (1992) orthogonal prediction configural frequency analysis (PCFA). Problems with this approach result from a lack of rules for specification of orthogonal comparisons, and because it is not obvious which comparisons are orthogonal. As an alternative it is proposed estimating non‐standard log‐linear models. These models specify orthogonal PCFA comparisons via orthogonal effect coding variables. This approach kadvantageous in that it allows researchers to simultaneously test orthogonal comparisons and PCFA parameter estimates.
Influence of the Interaction for Fitness on the Population Structure
Authors: Bartoloni Norberto
Published: May 2007

The incidence of non‐allelic interaction for fitness in a diallelic digenic model is analyzed. Three types of interaction between the fitnesses are considered, namely: i) additive, ii) exponential and, iii) logarithmic. The model of MATHER and JINKS (1970) is applied in the computation of the interaction parameters. The theory of finite absorbing Markov chains (FELLER, 1968) is utilized in the representation of the genotypic structure of the selfing population over time. Expressions depending on the parameters of interaction are obtained for the mean number of generations that the process of genetic information flow delays in transitions among transient states. Also, a numerical example is studied in which the mean absorption times and the variances are calculated. Finally, the impact of fitness interaction on the genetic diversity of some populations is analyzed through the calculation of the genetic information neg‐entropy (BRILLOUIN, 1959).
A Mathematical Model for the Effect of Water Pollutants on the Growth Pattern of Pollen
Authors: Pal Srimanta , Pal Ruma
Published: May 2007

The heavy metals as water pollutants had some adverse effects on the growth pattern of pollen grains of the aquatic macrophytes viz. Ottelia, Vallisneria, Hyderilla and Eichhornia. The germination of pollen grains were inversely proportional and the abnormality of pollen tube and the flowering time were directly proportional to the concentration of the heavy metal. In this paper we have presented a mathematical model that is the germinability and the abnormality changes with the log‐value of concentration in a straight line fashion. Also the flowering time changes with treatment time in an exponential pattern.
Some Results on the Tukey‐Mclaughlin and Yuen Methods for Trimmed Means when Distributions are Skewed
Authors: Wilcox Rand R.
Published: May 2007

In applied work, distributions are often highly skewed with heavy tails, and this can have disastrous consequences in terms of power when comparing groups based on means. One solution to this problem in the one‐sample case is to use the TUKEY and MCLAUGHLIN (1963) method for trimmed means, while in the two‐group case YUEN's (1974) method can be used. Published simulations indicate that they yield accurate confidence intervals when distributions are symmetric. Using a Cornish‐Fisher expansion, this paper extends these results by describing general circumstances under which methods based on trimmed means can be expected to give more accurate confidence intervals than those based on means. The results cover both symmetric and asymmetric distributions. Simulations are also used to illustrate the accuracy of confidence intervals using trimmed means versus means.
Preliminary Selection of Sires on Partial Records in Dairy Cattle
Authors: Sethi I. C. , Jain J. P.
Published: May 2007

Progeny testing of sires is costly as well as time consuming. The cost and testing time for part sample of sires can be reduced by basing sire evaluation on partial first lactation records. But it results in genetic loss due to decrease in the accuracy of selection. The present paper is an empirical attempt to study the optimum level of preliminary culling on partial records from two different considerations for both large and small populations. It is seen that even for moderate genetic correlation between partial and complete records ( = 0.6) preliminary culling as high as 50% can be effected with advantage.
Robustness of the Standard Deviation and Other Measures of Dispersion
Authors: Högel J. , Schmid W. , Gaus W.
Published: May 2007

Contaminated observations (e.g. outliers) and heavy tails in the underlying distribution influence the standard deviation as a measure of dispersion even more than, e.g., the mean. Other measures of dispersion, namely absolute deviation, (α, β)‐trimmed standard deviation, interquartile range and median absolute deviation (MAD) are defined for population, their properties — especially robustness — are explained and estimators are given, discussed and computed for a medical example. It is investigated how these measures of dispersion can be used to estimate a scale parameter of the underlying distribution more robustly. In numerical comparisons and simulations the robustness of these measures is demonstrated for heavy tailed distributions and contaminated distributions. Among other proposals it is recommended to use the (α, β)‐trimmed standard deviation and transform it to the ordinary standard deviation for easier interpretation, if possible.
The Complex Index for Comparison of Cancer Treatments Effectiveness
Authors: Goot R. E. , Kulagin P. A.
Published: May 2007

A complex index for comparison of treatment methods effectiveness is proposed. Procedure of the index construction allows the investigator to take into account several particular effectiveness characteristics considering their relative weight in over‐all efficiency.
A Group Sequential Method for one Standard Control and more than one Experimental Treatment
Authors: Lui Kung‐Jong
Published: May 2007

Many group‐sequential test procedures have been proposed to meet the ethical need for interim analyses. All of these papers, however, focus their discussion on the situation where there are only one standard control and one experimental treatment. In this paper, we consider a trial with one standard control, but with more than one experimental treatment. We have developed a group‐sequential test procedure to accommodate any finite number of experimental treatments. To facilitate the practical application of the proposed test procedure, on the basis of Monte Carlo simulation, we have derived the critical values of α‐levels equal to 0.01, 0.05 and 0.10 for the number of experimental treatments ranging from 2 to 4 and the number of multiple group sequential analysis ranging from 1 to 10. Comparing with a single non‐sequential analysis that has a reasonable power (say, 0.80), we have demonstrated that the application of the proposed test procedure may substantially reduce the required sample size without seriously sacrificing the original power.
Experiment with Split‐Plot Generated by PBIB Designs
Authors: Brzeskwiniewicz Henryk
Published: May 2007

The paper refers to the construction of two‐factor experiments carried out in incomplete split‐plot design in which levels of both factors occur as treatments in PBIB designs. It presents also the analysis of variance of these experiments based on partial analyses in the so called strata. These strata are connected with the variability between subplots inside wholeplots, between the wholeplots inside blocks and between blocks inside the total experiment.
Fitting Survival Data to a Piecewise Linear Hazard Rate in the Presence of Covariates
Authors: Recknor Julie C. , Gross Alan J.
Published: May 2007

This paper extends the work of KODLIN (1967), who proposed a method for analyzing patient survival data wherein the hazard rate was linearly related to the survival time. The present paper extends Kodlin's model to permit maximum likelihood estimation of the parameters so that covariate effects are included and the slope and intercept parameters are allowed to change over fixed intervals of the time domain of study. An illustration of the method using multiple myeloma data is given and the results are compared with those of Kodlin's model, the Feigl‐Zelen, Zippin‐Armitage model, the exponential model, and Cox's proportional hazards model.
On A Statistical Test to Detect Spatial Pattern
Authors: Sun Ping , Hughes G.
Published: May 2007

In the analysis of spatial patterns, the most extensively used index of dispersion is s2/m in which s2 and m are respectively the sample variance and sample mean of the count x in each sample unit. For statistical testing, the statistic I' = (n — 1) s2/m has been introduced since it has an approximate X distribution under the null hypothesis that individuals are distributed randomly. The main problem with the use of index I' is that the random distribution and the superdispersed distribution are not distinguished. In this paper, we have tried to induce a new statistical method for the detection of spatial pattern, based on the special characteristic of Poisson distribution that both of the m and s2 are the unbiased estimates of the parameter.
Inference on Collapsibility in Generalized Linear Models
Authors: Greenland S. , Maldonado George
Published: May 2007

GREENLAND and MICKEY (1988) derived a closed‐form collapsibility test and confidence interval forIxJxKcontingency tables with qualitative factors, and presented a small simulation study of its performance. We show how their method can be extended to regression models linear in the natural parameter of a one‐parameter exponential family, in which the parameter of interest is the difference of “crude” and “adjusted” regression coefficients. A simplification of the method yields a generalization of the test for omitted covariates given by HAUSMAN (1978) for ordinary linear regression. We present an application to a study of coffee use and myocardial infarction, and a simulation study which indicates that the simplified test performs adequately in typical epidemiologic settings.
Lessons learned from building and calibrating the ICWall, a stereo tiled display
Authors: van der Schaaf Tom , Germans Desmond , E. Bal Henri , Koutek Michal
Published: May 2007

Implementation of stereo tiled displays is a rather demanding task. In this article we want to share the lessons we have learned during the design and construction of the ICWall tiled display. This large display, used in a classroom setting, is a high‐resolution stereo tiled display (2 × 8 tiles), built from low‐cost commodity components. The overall image is produced by an array of projectors. When building such a system, a key challenge is to align the projector images. We describe our automated approach for alignment/calibration of the left‐ and right‐eye stereo images. We provide measurements that show accuracy of this procedure. We explain and compare two calibration approaches: a single‐pass and a two‐pass rendering method to align the tiled images. We explain how to provide seamless image on the tiled display and which issues have to be solved. We also discuss the depth perception issues on the ICWall for the large audiences. Another important aspect, is the architecture of the software used for PC‐cluster‐based rendering. We describe Aura, the parallel scene graph API that is used for rendering on our tiled display. Copyright © 2007 John Wiley & Sons, Ltd.
Integration of colour and textural information in multivariate image analysis: defect detection and classification issues
Authors: Prats‐Montalbán J. M. , Ferrer A.
Published: May 2007

In industrial processes, the detection and visualisation of defects and the development of efficient automated classification tools are strategic issues, especially when dealing with random colour textures (RCTs). This paper discusses the benefits of integrating colour and spatial (i.e. textural) information of digital RGB colour images in multivariate image analysis (MIA) to deal with these topics. Regarding the first one, a simple and computational cost‐effective monitoring procedure based on colour‐textural MIA merged with multivariate statistical process control (MSPC) ideas is outlined. Two novel computed images: T2and RSS Images are proposed. The procedure is applied on digital RGB colour images from artificial stone plates. With respect to the second issue, when colour‐textural MIA is used for image classification a lot of factors (e.g. pre‐processing, modelling, …) likely affecting the success rate in the classification (SRC) show up. This paper presents a methodology based on the combination of experimental design and logistic regression for choosing the best combination of factors to maximise the SRC of different types of images. Digital RGB colour images from ceramic tiles and orange fruits are used to illustrate the potential of the proposed methodology. Copyright © 2007 John Wiley & Sons, Ltd.
The impact of temperature variations on spectroscopic calibration modelling: a comparative study
Authors: Chen Tao , Martin Elaine
Published: May 2007

Temperature fluctuations can have a significant impact on the repeatability of spectral measurements and as a consequence can adversely affect the resulting calibration model. More specifically, when test samples measured at temperatures unseen in the training dataset are presented to the model, degraded predictive performance can materialise. Current methods for addressing the temperature variations in a calibration model can be categorised into two classes—calibration model based approaches, and spectra standardisation methodologies. This paper presents a comparative study on a number of strategies reported in the literature including partial least squares (PLS), continuous piecewise direct standardisation (CPDS) and loading space standardisation (LSS), in terms of the practical applicability of the algorithms, their implementation complexity, and their predictive performance. It was observed from the study that the global modelling approach, where latent variables are initially extracted from the spectra using PLS, and then augmented with temperature as the independent variable, achieved the best predictive performance. In addition, the two spectra standardisation methods, CPDS and LSS, did not provide consistently enhanced performance over the conventional global modelling approach, despite the additional effort in terms of standardising the spectra across different temperatures. Considering the algorithmic complexity and resulting calibration accuracy, it is concluded that the global modelling (with temperature) approach should be first considered for the development of a calibration model where temperature variations are known to affect the fundamental data, prior to investigating the more powerful spectra standardisation approaches. Copyright © 2007 John Wiley & Sons, Ltd.
The Drosophila CLASP homologue, Mast/Orbit regulates the dynamic behaviour of interphase microtubules by promoting the pause state
Authors: Sousa Aureliana , Reis Rita , Sampaio Paula , Sunkel Claudio E.
Published: May 2007

An important group of microtubule associated proteins are the plus‐end tracking proteins which includes the Mast/Orbit/CLASPs family amongst others. Several of these proteins have important functions during interphase and mitosis in the modulation of the dynamic properties of microtubules, however, the precise mechanism remains to be elucidated. To investigate the role of Mast in the regulation of microtubule behaviour during interphase, we used RNAi in Drosophila S2 culture cells stably expressing GFP‐α‐tubulin and followed the behaviour of microtubules in vivo. Mast depleted cells show a significant reduction of microtubule density and an abnormal interphase microtubule array that rarely reaches the cell cortex. Analysis of the dynamic parameters revealed that in the absence of Mast, microtubules are highly dynamic, constantly growing or shrinking. These alterations are characterized by a severe reduction in the transition frequencies to and from the pause state. Moreover, analysis of de novo microtubule polymerization after cold treatment showed that Mast is not required for nucleation since Mast depleted cells nucleate microtubules soon after return to normal temperature. Taken together these results suggest that Mast plays an essential role in reducing the dynamic behaviour of microtubules by specifically promoting the pause state. Cell Motil. Cytoskeleton 2007. © 2007 Wiley‐Liss, Inc.
Mono‐ and Heterodimetallic FeII and RuII Complexes Based on a Novel Heteroditopic 4′‐{Bis(phosphanyl)aryl}‐2,2′:6′,2″‐terpyridine Ligand (Eur. J. Inorg. Chem. 15/2007)
Authors: Gagliardo Marcella , Perelaer Jolke , Hartl František , van Klink Gerard P. M. , van Koten Gerard
Published: May 2007

The cover picture shows, with the help of a heteroditopic tpy‐pincer building block, the preparation of heterodimetallic complexes through the “complex as ligand” approach. Even with such small building blocks the construction of large molecular assemblies will eventually be possible. A beautiful example of small building blocks leading to large constructions is the Aquaduct Segovia, a masterpiece of classical Roman architecture. Details of the synthesis and structures of the heterodimetallic complexes are described in the article by G. van Koten et al. on p. 2111 ff.
High‐throughput CZE‐UV determination of arginine and dimethylated arginines in human plasma
Authors: Zinellu Angelo , Sotgia Salvatore , Zinellu Elisabetta , Pinna Antonio , Carta Francesco , Gaspa Leonardo , Deiana Luca , Carru Ciriaco
Published: May 2007

Experimental studies document that increased asymmetric dimethylarginine (ADMA) blood levels inhibit NOS significantly, reducing NO generation. ADMA measurement often needs sample cleanup by SPE prior to chromatography and precolumn derivatization that cannot be easily employed in a routine clinical setting. We set up a new reliable CE method to measure ADMA, symmetric dimethylarginine (SDMA), and arginine without sample extraction or precolumn derivatization in order to examine their concentrations in human plasma. Sample was concentrated prior to CE injection and analytes were monitored by UV detection. CE analysis was performed in an uncoated fused‐silica capillary, 75 μm id and 60.2 cm length (50 cm to the detection window), injecting 1 s water plug (0.5 psi) followed by 10 s of the sample (0.5 psi). Separation was carried out in a 50 mmol/L Tris‐phosphate run buffer at pH 2.30, 15°C and 15 kV (75 μA) at normal polarity. Recovery of plasma ADMA was 101–104% and inter‐day CV was less than 3%. Assay performance was evaluated measuring the levels of arginine and its dimethyl derivatives in 77 subjects. Passing–Bablok regression and Bland–Altman test for methods comparison suggest that the data obtained by our method and by a reference CE–LIF assay are similar.
Genetic random effects model for family data with long‐term survivors: analysis of diabetic nephropathy in type 1 diabetes
Authors: Pitkäniemi Janne , Moltchanova Elena , Haapala Laura , Harjutsalo Valma , Tuomilehto Jaakko , Hakulinen Timo
Published: May 2007

A shared and additive genetic variance component‐long‐term survivor (LTS) model for familial aggregation studies of complex diseases with variable age‐at‐onset phenotype and non‐susceptible subjects in the study cohort is proposed. LTS has been used from the early 1970s, especially in epidemiological studies of cancer. The LTS model utilizes information on the age at onset (survival) distribution to make inference on partially latent susceptibility. Bayesian modeling with uninformative priors is used and estimates of the posterior distribution of age at onset and susceptibility parameters of interest have been obtained using Bayesian Markov chain Monte Carlo (MCMC) methods with OpenBugs program. A simulation study confirms that we obtain posterior estimates of the model parameters on shared and genetic variance components of age at onset and susceptibility with good coverage rates. Further, we analyze familial aggregation of diabetic nephropathy (DN) in large Finnish cohort of 528 sibships with type 1 diabetes (T1D). According to the variance components estimated a substantial familial variation in the susceptibility to DN exist among families, while time to DN is less influenced by shared familial factors.Genet. Epidemiol. 2007. © 2007 Wiley‐Liss, Inc.
Designing standardized clinical protocols: Some organizational and behavioral issues
Authors: Saltman Richard
Published: May 2007

In the present environment, the clinical ordering patterns of hospital‐based physicians can be expected to come under increasing scrutiny. This paper considers three major aspects of the case for inpatient clinical ordering protocols. First, it reviews the argument that hospitals do not, at present, exercise adequate management over physician‐triggered resource consumption. Subsequently, the paper examines existing but partial protocol models in the United States and Scandinavia that could provide a basis for an adequate physician management system. In its third section, the paper explores the fundamental characteristics of a full‐fledged Standardized Clinical Protocol (SCP) system, developing two alternative ‘ideal‐type’ models for further discussion. The paper concludes with the argument that physicians, rather than economists or politicians, should control the design of future protocol systems.
Performance indicators and performance assessment in the UK national health service: Implications for management and planning
Authors: Birch Stephen , Maynard Alan
Published: May 2007

Throughout the Western world policy makers are seeking to control the use of health care resources. Often the primary motive for these policies is to control costs or the total level of public expenditure on health care. One manifestation of such policies in the USA is the use of diagnostic related groups (DRGs), and this instrument is now being adopted in Europe (for example, in France as from January 1986). In Britain, a similar management tool is that of performance indicators, which are basically measures of input and activity. In this article it is argued that management responses to these measures may not lead to greater efficiency in resource utilization. Whilst the use of input and process measures to control resource allocation are better than no controls at all, the achievement of efficiency requires that such measures are supplemented with the assessment of outcomes and analyses of input‐output relationships. Such supplementation, for example by using quality‐adjusted life years (QALYs), is urgently required if policy makers are not to become disenchanted with the usefulness of existing performance indicators.
Minimum primary health care interventions for child survival: Setting the research agenda
Authors: Gish Oscar
Published: May 2007

With the purpose of exposing some of the underlying issues, the first part of the article discusses the background and assumptions inherent to the idea of minimum primary health care interventions for child survival. The second part puts forward some areas for study, based upon their potential importance to child health and survival. International and national approaches to ‘minimum interventions’ are seen as being rooted in their political contexts, including the wider debate over the relationships between economic growth, development and the meeting of basic needs.

To have relevance for health planning and management, it is argued that research agendas concerned with the impact of primary health care (PHC) interventions upon child survival must be: country‐specific; start with ‘what is’; and take entire national frameworks into account, including the respective roles and effects of the private and public sectors. Potentially useful research activities are discussed in the areas of coverage and resource allocation, and with regard to the development of minimum norms and standards. Proposals are made for setting a research agenda for PHC programmes in Mexico.
Planning and management for health in periods of economic stringency and instability: A contingency approach
Authors: Werff Albert Van Der
Published: May 2007

The mid‐1970s marked the end of the longest period of uninterrupted economic growth in history, and initiated in Europe — and other parts of the world — a period of economic stagnation and instability. Along with the prosperity explosion of the past, the pattern of health problems has changed and is still changing. Moreover, the demand for health care has kept on rising, without much improvement of health status in general. Thus, there is a critical need to rethink policies, and to ensure that future changes occur within the limits of shrinking resources and the allotted time‐span. In particular, the change in priorities envisaged by the Health for All 2000 (HFA 2000) strategies will need to take place against the background of an ageing population, social instability, and continuing development of new lifestyles and persistent economic scarcity. It is by analysing that background, that this article seeks to make recommendations as to how health planning and management might successfully cope with the policy reorientation of the HFA 2000 strategy.

The structure of this article is as follows. Firstly, the changes taking place in planning conditions will be reviewed, and form the basis of a framework for subsequent analysis of the ‘planning environment’. Following this framework, some of the conflicts likely to be faced in planning and management will be discussed, many of which are the consequence of economic stringency and instability. Also the requirements for an improvement of the effectiveness and efficiency of planning will be identified. Finally, a limited number of approaches to planning will be considered, for their appropriateness to the present‐day economic circumstances.

The point of view elucidated throughout is that there is no single solution which is ‘best’ under all circumstances. The conclusion, rather, is that the selection of a particular theory or method of planning and management should depend both on the objectives of the decision maker and on the determinants of the planning environment. General prescriptions should not be made. At the same time, some elements have to be stressed in all types of planning, namely: the orientation towards outcomes or outputs or problems; the attention to long‐term strategic thinking; and, the application of more efficient, flexible and less bureaucratic approaches.
Consequences for hospitals resulting from demographic, social and morbidity changes: A European perspective
Authors: Pfaff Martin , Nagel Frieder
Published: May 2007

The last 40 years has been a time of rapid demographic, social and economic change in most countries of the world. In Europe, the ageing of the population, a decrease in household size, and the reduced importance of parasitic and infectious diseases along with an increase in chronic and degenerative diseases are some of the most notable results of industrialization, urbanization and medical progress. These developments lead to changing demands not only for the services of hospitals but upon the health care system at large. Most recently, and in addition, these changes have had to be faced under resource constraints resulting from decreased economic growth.

This article focuses on the similarities and differences within and across the health care systems of European countries, and on their efforts to respond to the changes which have taken place and are likely to continue in the near future. In so doing, it relates the various demographic, social and economic changes taking place in these countries to the structural changes noticeable in the hospital sector.

The results obtained by statistical analyses of empirical evidence lead us to conclude that demographic and social variables may better explain the differences in hospital use within a given country over longer stretches of time than across countries at a given point in time. In the latter case, economic variables—differences in gross domestic product (GDP) per capita—serve as major explanations of the cross‐country differences found. Changes in demographic, social and morbidity factors are also mirrored in the relative importance of hospital departments, at a given point in time and also in changes over time.

Major changes have taken place within the health care systems. Hospitals are losing ground to other forms of health care: for instance, to institutions providing pre‐hospital and post‐hospital treatment. The need for more caring patterns of service, rather than for more curing, accounts for yet another overall trend. Hospitals have started to respond to this need by offering more ‘semi‐stationary’ and part‐time health care facilities. These developments go hand in hand with the establishment of closer relations between hospitals and other facilities within the health care system, and with improved non‐stationary health care services.
British and American health policy: Recent lessons from one system to the other
Authors: Paton Calum
Published: May 2007

Arguably, US and British health‐care policies have shown some convergence in recent years, despite vast differences in the two health‐care systems. In part, this reflects the incentives common to all systems which must be mobilized to improve efficiency and effectiveness; in part, this reflects the (two‐way) trans‐Atlantic ‘trendiness’ of ideas. This article seeks to examine the main context of policy affecting the two health‐care systems, the means now used to achieve the systems' goals, and the validity of claims of convergence. The focus is conceptual, although a significant aim is to assess recent policies in a comparative framework.
Competition and survival of health service organizations: A population ecology approach
Authors: Kaluzny Arnold , Alexander Jeffrey , Hurley Robert , Galloway Robert
Published: May 2007

The survival of health care organizations is viewed, in this article, from a population ecology perspective. This perspective provides insight into how organizational forms are differentiated on the basis of resource availability under different environmental conditions. Selected hypotheses and a rationale are presented to illustrate the applicability of the perspective to health services.
Health system financing by social security
Authors: Roemer Milton I.
Published: May 2007

The article reviews, through a historical perspective, the development world‐wide in social security systems for financing health care, considers the various patterns of health care funded by such systems, and identifies a number of the strengths and alleged weaknesses of the health insurance concept especially in the developing world. Though a range of options exists for mobilizing additional resources to the health sector, the adoption of statutory health insurance stands out as the single most practical strategy for increasing expenditures in health systems—especially expenditures on organized patterns of delivering primary health care.
The effect of centralized hospital administration on financial control and hospital service delivery: The case of Hong Kong
Authors: Chu David K. W.
Published: May 2007

Administration, financial control and service delivery are three mutually influential dimensions of a hospital system. The centralized hospital system of Hong Kong is a case‐in‐point that illustrates such influence. By spending only a small fraction of the Gross Domestic Product each year, the government has been able to provide limited modern health care services at nominal financial cost to the public. At the same time, hospitals are subject to a strict system of administrative and financial controls. Consequently, Hong Kong hospitals must utilize their limited facilities effectively to provide modern health services to the public. However, the trade‐off between low‐cost health services and limited facilities is the incurrence, by the public, of non‐monetary costs in obtaining hospital admission.
Coping with regional variations: The case of surgery in Denmark
Authors: Andersen Tavs Folmer , Blais Regis , Bredesen Jesper , Jørgensen Torben , Loft Anne , Madsen Mette , Mooney Gavin , Sejr Torben
Published: May 2007

This article examines some of the key research and policy issues that are emerging as a result of recent analyses of regional variations in health care. The article presents a historical background to this important new field of health services' research, and indicates, using some Danish examples of research on hysterectomy, cholecystectomy, and prostatectomy, the revelance of this research to management and policy planning. Regional variations are not yet fully explained in terms of what causes them. What is clear and what is the primary focus of this article is that their very existence, whatever their explanation, creates a major challenge for the management and planning of future health services.
Monitoring regional performance in general hospital psychiatry: England, Wales and Czechoslovakia
Authors: Frost C. E. B. , Forster D. P.
Published: May 2007

The purpose of this article is to consider how the regional performance of general hospital psychiatry may be adequately monitored using routine information. Limitations on the types of information available for monitoring regional performance are discussed, in the context of the main functions which a routine information service may be expected to fulfill. English and Welsh routine data are used in a study of the utilisation of general hospital psychiatric beds, and then compared with similar data for Czechoslovakia. The findings suggest that regional equity in the provision of beds: as measured by the coefficient of variation of the bed supply rate, and national performance, as measured by the ‘marginal throughput’ of these beds; is superior in Czechoslovakia despite recent additions to such beds in England and Wales. The model of utilisation, which was used to assess national performance, may be used to identify the regions whose performance is substandard when compared to other regions or countries. Finally, the relevance of these proposals for monitoring Health Service performance generally is discussed.