bluuebunny/crossref_metadata_2025 huggingface dataset:
Building logistic models by means of a non parametric goodness of fit test: a case study
Authors: le Cessie S. , van Houwelingen J. C.
Published: April 2008

A sequence of logistic models is fitted to data from a Dutch follow‐up study on preterm infants (POPS). To examine the adequacy of the model, a recently developed non parametric method to check goodness of fit is applied (le Cessie and Van Houwelingen (1991)). This method uses a test statistic based upon kernel regression methods.

In this paper the problem of choosing a “best” bandwidth, corresponding to the greatest power of the test statistic, is avoided by computing the test statistic for a range of different bandwidths. Testing is then based upon the asymptotic distribution of the maximum of the test statistics.

The testing method is used as a goodness of fit criterion, and the contribution of each individual observation to the test statistic is used as a diagnostic tool to localize deviations of the model, and to determine directions in which the model can be improved.
Efficiency of iterated WLS in the linear model with completely unknown heteroskedasticity
Authors: van der Genugten B. B.
Published: April 2008

Iterated weighted least squares (IWLS) is investigated for estimating the regression coefficients in a linear model with symmetrically distributed errors. The variances of the errors are not specified; it is not assumed that they are unknown functions of the explanatory variables nor that they are given in some parametric way.

IWLS is carried out in a random number of steps, of which the first one is OLS. In each step the error variance at time t is estimated with a weighted sum of m squared residuals in the neighbourhood of t and the coefficients are estimated using WLS. Furthermore an estimate of the co‐variance matrix is obtained. If this estimate is minimal in some way the iteration process is stopped.

Asymptotic properties of IWLS are derived for increasing sample size n. Some particular cases show that the asymptotic efficiency can be increased by allowing more than two steps. Even asymptotic efficiency with respect to WLS with the true error variances can be obtained if m is not fixed but tends to infinity with n and if the heteroskedasticity is smooth.
Bayes estimates of muIti‐criteria decision alternatives using Monte Carlo integration
Authors: Boender C. G. E. , van Dijk H. K.
Published: April 2008

A Bayesian procedure is proposed for the estimation of the weights of the alternatives in a multi‐criteria decision model with data that stem from pair‐wise comparison of alternatives. The prior information restricts the weights to the unit simplex. The posterior results are computed by Monte Carlo integration procedures based on importance sampling. The Bayesian procedure is applied to a case study concerning the choice of a professor of Operations Research (OR). Results are: (1) according to the Bayesian procedure a different candidate would be chosen as professor of OR than according to the maximum likelihood procedure; (2) given the prior and data information, there exists a substantial probability of taking the wrong decision; (3) there exists a ranking of the candidates with a posterior probability greater than one half.
Testing equality of variances in the analysis of repeated measurements
Authors: Kallenberg W. C. M. , Mudholkar G. S. , Subbaiah P.
Published: April 2008

The problem of comparing the precisions of two instruments using repeated measurements can be cast as an extension of the Pitman‐Morgan problem of testing equality of variances of a bivariate normal distribution. Hawkins (1981) decomposes the hypothesis of equal variances in this model into two subhypotheses for which simple tests exist. For the overall hypothesis he proposes to combine the tests of the subhypotheses using Fisher's method and empirically compares the component tests and their combination with the likelihood ratio test. In this paper an attempt is made to resolve some discrepancies and puzzling conclusions in Hawkins's study and to propose simple modifications.

The new tests are compared to the tests discussed by Hawkins and to each other both in terms of the finite sample power (estimated by Monte Carlo simulation) and theoretically in terms of asymptotic relative efficiencies.
On the application of the Minkowski‐Farkas theorem to sampling designs
Authors: Akahira M. , Takeuchi K.
Published: April 2008

In the paper, we consider the following problem: Let {πk} be a sequence satisfying 0πkΣ1 (k=1,…, N) and π=n.Tben, is there an unordered sampling design such that, for each k=1,…N, the inclusion probability of unit k is equal to π? It is shown that it can be solved by the straightforward application of the Minkowski‐Farkas theorem.
On randomization, modeling and experimental design: some remarks on a paper by De Vos
Authors: Jansen M.J.W.
Published: April 2008

De Vos (1991) claims to have discovered a new example from agricultural field experimentation which shows that a simple robust spatial model may lead to inference and systematic experimental design that outperforms the inference from randomized experiments by far. In this reaction it is shown that: (1) the example is not new; (2) the gains in efficiency are exaggerated due to comparison with an inefficient randomization method; (3) the paper is over‐optimistic with respect to robustness of model‐based methods and throws unjustified doubts on the validity of randomization methods; (4) the choice between randomization methods and model‐based methods depends on the relative importance attached to efficiency and validity.
Bridging the gap between a stationary point process and its Palm distribution
Authors: Nieuwenhuis G.
Published: April 2008

In the context of stationary point processes measurements are usually made from a time point chosen at random or from an occurrence chosen at random. That is, either the stationary distribution P or its Palm distribution P° is the ruling probability measure. In this paper an approach is presented to bridge the gap between these distributions. We consider probability measures which give exactly the same events zero probability as P°, having simple relations withP. Relations betweenPand P° are derived with these intermediate measures as bridges. With the resulting Radon‐Nikodym densities several well‐known results can be proved easily. New results are derived. As a corollary of cross ergodic theorems a conditional version of the well‐known inversion formula is proved. Several approximations of P° are considered, for instance the local characterization ofPoas a limit of conditional probability measuresP°N The total variation distance betweenP°and P1can be expressed in terms of the P‐distribution function of the forward recurrence time.
The one‐sided Kolmogorov‐Smirnov test in signal detection problems with Gaussian white noise
Authors: Drees H. , Milbrodt H.
Published: April 2008

In this paper, we investigate the power of the Kolmogorov‐Smirnov test for negativity of signals in signal detection problems with Brownian motion noise. Strict unbiasedness and admissibility are established. Moreover, taking up an approach of Häjek and Sidäk (1967) for the classical Brownian bridge case, we compute the directional derivative of the power function at the hypothesis, thus obtaining the principal direction of alternatives of the test. As an application, in a hazard rates set‐up, one‐sided Rényi‐tests may be adjusted by choosing their weight function such that they are most sensitive against a prescribed type of alternatives. Finally, we give some numerical and simulation results.
KMT‐type inequalities and goodness‐of‐fit tests
Authors: Koning A. J.
Published: April 2008

The implications of the probability inequality of Komløs, Major and Tusnády (1975) for the theory of goodness‐of‐fit tests, especially tests based on stochastic integrals with respect to the basic martingale in the random censoring model, are discussed. Choices of the integrand of the stochastic integral which yield highly efficient generalized rank and supremum type tests are given for the simple as well as the composite null hypothesis.
Multivariate statistical process control—recent results and directions for future research
Authors: Wierda S. J.
Published: April 2008

The performance of a product often depends on several quality characteristics. These characteristics may have interactions. In answering the question “Is the process in control?”, multivariate statistical process control methods take these interactions into account. In this paper, we review several of these multivariate methods and point out where to fill up gaps in the theory. The review includes multivariate control charts, multivariate CUSUM charts, a multivariate MMA chart, and multivariate process capability indices. The most important open question from a practical point of view is how to detect the variables that caused an out‐of‐control signal. Theoretically, the statistical properties of the methods should be investigated more profoundly.
A note on Model Reference Adaptive System (MRAS) estimate with infinite variance
Authors: Thavaneswaran A. , Abraham B.
Published: April 2008

This paper discusses the estimation of a parameter in an autoregressive model with infinite variance. A recursive estimation procedure based on minimizing the prediction errors is provided. It is also shown that the model reference adaptive system estimate for an AR (1) model given in Aase (1983) is a special case.
Estimating word frequencies from lexical dispersion data1
Authors: Indefrey P. , Baayeny H.
Published: April 2008

A method for estimating word frequencies on the basic's of lexical dispersion data that makes use of some results in occupancy theory is outlined. The accuracy of the method, which assumes that words occur independently in texts, is tested on Lewis Carroll's “Alice in Wonderland”. Although intra‐textual and inter‐textual cohesion can be traced as sources of misfit, the probabilistic aspect of the relation between frequency and dispersion is strong enough to allow lower boundary estimates of word frequency to be obtained for roughly 75% of the words.
A goodness‐of‐fit test in the multinomial legit model based on weighted squared residuals
Authors: Windmeijer F.A.G.
Published: April 2008

The asymptotic (normal) distribution of the sum of weighted squared residuals in the multinomial logit model is derived. The performance of a chi‐squared test based on the asymptotic normality is discussed using some empirical examples.
Practical estimation of multivariate densities using wavelet methods
Authors: Tribouley K.
Published: April 2008

This paper describes a practical method for estimating multivariate densities using wavelets. As in kernel methods, wavelet methods depend on two types of parameters. On the one hand we have a functional parameter: the wavelet Ø (comparable to the kernel K) and on the other hand we have a smoothing parameter: the resolution index (comparable to the bandwidth h). Classically, we determine the resolution index with a cross‐validation method. The advantage of wavelet methods compared to kernel methods is that we have a technique for choosing the wavelet Ø among a fixed family. Moreover, the wavelets method simplifies significantly both the theoretical and the practical computations.
Distributional inference
Authors: Kroese A. H. , van der Meulen E. A. , Poortema K. , Schaafsma W.
Published: April 2008

The making of statistical inferences in distributional form is conceptionally complicated because the epistemic ‘probabilities’ assigned are mixtures of fact and fiction. In this respect they are essentially different from ‘physical’ or ‘frequency‐theoretic’ probabilities. The distributional form is so attractive and useful, however, that it should be pursued. Our approach is In line with Walds theory of statistical decision functions and with Lehmann's books about hypothesis testing and point estimation: loss functions are defined, risk functions are studied, unbiasedness and equivariance restrictions are made, etc. A central theme is that the loss function should be ‘proper’. This fundamental concept has been explored by meteorologists, psychometrists, Bayesian statisticians, and others. The paper should be regarded as an attempt to reconcile various schools of statisticians. By accepting what we regard 88 good and useful in the various approaches we are trying to develop a nondogmatic approach.
Random variables with independent integer and fractional parts
Authors: Marsaglia G.
Published: April 2008

For random variables with independent integer and fractional parts: a canonical form is given for those with positive differentiable densities, and a condition ensuring exponentially is made less restrictive.
Data editing and imputation from a computational point of view
Authors: Willenborg L. C. R. J.
Published: April 2008

Data editing and imputation are important activities in the processing of survey data. Several of their computational aspects are discussed. The logical structure of a questionnaire, as defined in Willenborg (1988), is the key structure considered in this paper. It is used as a starting point to describe these activities. The present paper is a continuation of Willenborg (1995).
Prediction of the next hypercalcemia free period: application of random effect models with selection on first event
Authors: Zwinderman A. H. , van Houwelingen J. C. , Schweitzer D.
Published: April 2008

The length of repeated hypercalcemia free periods of patients with bone metastasis of breast cancer with at least one hypercalcemic event was modelled according to a generalized linear mixed model formulated in terms of transition probabilities and according to a latent variable model. In the former case the periods were assumed to be lognormally distributed with two variance components (patients and residue). In the latter case the conditional intensity given a patient was assumed to be the intensity of the Weibull distribution, while the random patient effect (frailty) was assumed to be drawn from a gamma distribution. In both cases the selection of only patients with at least one hypercalcemic event was taken into consideration. In both models the variance of the patient effect turned out to be negligible. For the second and later periods the Weibull appeared to fit better than the lognormal model. For the first period there was almost no information available.
Longitudinal LISREL model estimation from incomplete panel data using the EM algorithm and the Kalman smoother
Authors: Jansen R. A. R. G. , Oud J. H. L.
Published: April 2008

Longitudinal data sets with the structureT(time points) ×N(subjects) are often incomplete because of data missing for certain subjects at certain time points. The EM algorithm is applied in conjunction with the Kalman smoother for computing maximum likelihood estimates of longitudinal LISREL models from varying missing data patterns. The iterative procedure uses the LISREL program in the M‐step and the Kalman smoother in the E‐step. The application of the method is illustrated by simulating missing data on a data set from educational research.
Asymptotically optimal estimation of smooth functionals for interval censoring, part 1
Authors: Geskus R. B. , Groeneboorn P.
Published: April 2008

Estimation in the interval censoring model is considered. A class of smooth functionals is introduced, of which the mean is an example. The asymptotic information lower bound for such functionals can be represented as an inner product of two functions. In case 1, i.e. one observation time per unobservable event time, both functions can be given explicitly. We mainly consider case 2, with two observation times for each unobservable event time, in the situation that the observation times can not become arbitrarily close to each other. For case 2, one of the functions in the inner product can only be given implicitly as solution to a Fredholm integral equation. We study properties of this solution and, in a sequel to this paper, prove that the nonparametric maximum likelihood estimator of the functional asymptotically reaches the information lower bound.
Variance components models for survival data
Authors: Petersen J. H. , Andersen P. K. , Gill R.D.
Published: April 2008

Extensions of the Cox proportional hazards model for survival data are studied where allowance is made for unobserved heterogeneity and for correlation between the life times of several individuals. The extended models are frailty models inspired by Yashinet al. (1995). Estimation is carried out using the EM algorithm. Inference is discussed and potential applications are outlined, in particular to statistical research in human genetics using twin data or adoption data, aimed at separating the effects of genetic and environmental factors on mortality.
Stability and self‐decomposability of semi‐group valued random variables
Authors: Hansen B. G.
Published: April 2008

A random variable X on IR+ is said to be self‐decomposable, dif for all c∈ (0, 1) there exists a random variable Xc on IR+ such that X=dcX+Xc. It is said to be stable if it is self‐decomposable and Xc=d (1 ‐ c)X', where X and X' are identically and independently distributed. The notions of stability and self‐decomposability for infinitely divisible random variables are generalised to abelian semi‐groups (S, +) with S having an identical involution, by using characteristic functions. The generalised definitions involve semi‐groups of scaling operators T. There operators can be interpreted in a slightly different context as generalised continuous‐time branching processes (with immigration). The underlying importance of the generator of the semi‐groups T in the characterisation of stability and self‐decomposability is stressed.
Two‐stage stochastic integer programming: a survey
Authors: Schultz R. , Stougie L. , van der Vlerk M. H.
Published: April 2008

Stochastic integer programming is more complicated than stochastic linear programming, as will be explained for the case of the two‐stage stochastic programming model. A survey of the results accomplished in this recent field of research is given.
TIME, PRESENCE, AND HISTORICAL INJUSTICE
Authors: BEVERNAGE BERBER
Published: April 2008

The relationship between history and justice traditionally has been dominated by the idea of the past as distant or absent (and with that, irreversible). This ambiguous ontological status makes it very difficult to situate the often‐felt “duty to remember” or obligation to “do justice to the past” in that past itself, and this has led philosophers from Friedrich Nietzsche to Keith Jenkins to plead against an “obsession” with history in favor of an ethics aimed at the present. History's ability to contribute to the quest for justice, as a result, often seems very restricted or even nonexistent. The introduction of the “presence”‐paradigm in historiography can potentially alter this relation between history and justice. However, to do so it should be conceived in such a way that it offers a fundamental critique of the metaphysical dichotomy between the present and the absent and the underlying concept of time (chronosophy) that supports this dichotomy. The “presence”‐paradigm can be emancipatory and productive only if presence and absence are not perceived as absolute dichotomies. In the first part of this article I elaborate on the influence that the present/absent dichotomy has on the notion of justice by introducing a conceptual contrast between what I will call the “time of jurisdiction” and the “time of history.” The second part of the article focuses on the way certain aspects of the dominant Western chronosophy reinforce the present/absent dichotomy and thereby prevent us from thoroughly exploring the ambiguous but often very problematic presence of the past. Throughout the article I refer to the relatively recent phenomenon of truth commissions and the context of transitional justice to discuss some challenges for the “presence”‐paradigm.
Reaching critical mass? Theory, politics, and the culture of debate in children's geographies
Authors: Vanderbeck Robert M
Published: April 2008

A small but growing number of voices have begun to raise questions about the current direction of children's geographies as a subfield and its status within the wider discipline. This article intervenes in these emerging discussions to examine the status of debate itself within children's geographies. I argue that children's geographies over the past decade has operated primarily in a consensus‐based mode, with a number of potential tensions and differences between practitioners masked as a result. I develop the example of notions of children's competent social agency, a core theoretical assumption that is rarely interrogated in much depth. In closing, I pose questions regarding several contemporary political issues concerning children's agency about which geographers have had surprisingly little to say. I suggest that explicitly addressing some of these vexing issues would contribute to a richer state of debate within children's geographies.
MIGRATION AND POPULATION CHANGE WITHIN METROPOLITAN TORONTO, 1966–71
Authors: Ingram David R.
Published: April 2008

Although net natural increase accounts for slightly more than half of the over‐all growth in the population of Metropolitan Toronto between 1966 and 1971, the redistribution of the 1966 population and the addition of people from outside the metropolitan area are more important in understanding spatial variations in population change. Longer‐term residents have tended to move away from the inner municipalities, but the pattern of a suburbanizing population has been obscured by the tendency of recent immigrants to reside in the inner areas.
Preparation of Silica/γ‐Alumina Membrane with Bimodal Porous Layer for Improved Permeation in Ions Separation
Authors: Ahmad Abdul Latif , Leo Choe Peng , Shukor Syamsul Rizal Abdul
Published: April 2008

Creating secondary pores in the intermediate layer of hierarchical ceramic membranes successfully increases the permeability of bi‐layered membranes by reducing the density of the separating layer. With the optimum secondary pore volume, the permeability of the silica/γ‐alumina membrane with low secondary volume is enhanced with a satisfactory retention of organic ions and inorganic ions. However, the silica layer is not well formed when excessive secondary pores were generated in the intermediate layer. This is likely because the bimodal porous structure of γ‐alumina with high secondary pore volume is inadequate to prevent the penetration of silica sol into the α‐alumina support during dip coating. Thus, the bi‐layered membrane with high secondary pore volume shows insufficient retention of Reactive Orange 16 dye and NaCl at low pH.
In Situ Reaction Synthesis, Electrical and Thermal, and Mechanical Properties of Nb4AlC3
Authors: Hu Chunfeng , Li Fangzhi , He Lingfeng , Liu Mingyue , Zhang Jie , Wang Jiemin , Bao Yiwang , Wang Jingyang , Zhou Yanchun
Published: April 2008

In this work, a bulk Nb4AlC3 ceramic was prepared by an in situ reaction/hot pressing method using Nb, Al, and C as the starting materials. The reaction path, microstructure, physical, and mechanical properties of Nb4AlC3 were systematically investigated. The thermal expansion coefficient was determined as 7.2 × 10−6 K−1 in the temperature range of 200°–1100°C. The thermal conductivity of Nb4AlC3 increased from 13.5 W·(m·K)−1 at room temperature to 21.2 W·(m·K)−1 at 1227°C, and the electrical conductivity decreased from 3.35 × 106 to 1.13 × 106Ω−1·m−1 in a temperature range of 5–300 K. Nb4AlC3 possessed a low hardness of 2.6 GPa, high flexural strength of 346 MPa, and high fracture toughness of 7.1 MPa·m1/2. Most significantly, Nb4AlC3 could retain high modulus and strength up to very high temperatures. The Young's modulus at 1580°C was 241 GPa (79% of that at room temperature), and the flexural strength could retain the ambient strength value without any degradation up to the maximum measured temperature of 1400°C.
Promotion of exclusive breastfeeding is not likely to be cost effective in West Africa. A randomized intervention study from Guinea‐Bissau
Authors: Jakobsen Marianne S. , Sodemann Morten , Biai Sidu , Nielsen Jens , Aaby Peter
Published: April 2008

Aim: To evaluate the impact of promotion of exclusive breastfeeding on infant health in Guinea‐Bissau, West Africa, where mortality rates are high, breastfeeding is widely practiced but exclusive breastfeeding is rare.

Method: At the Bandim Health Project in Guinea Bissau, West Africa, a birth cohort of 1721 infants were randomized to receive health education: promotion of exclusive breastfeeding for the first 4–6 months of life according to WHO recommendations at the time of the study. All children were followed from birth to 6 months of age.

Results: Introduction of both water and weaning food was significantly delayed in the intervention group. However we found no beneficial health effects of the intervention; there was no reduction in mortality in the intervention group compared with the control group (mortality rate ratio: 1.86 (0.79–4.39)), weight at 4–6 months of age was significantly lower in the intervention group (7.10 kg vs. 7.25 kg; Wilcoxon two‐sample test: p = 0.03). There was no difference in diarrhoea morbidity and hospitalization rates.

Conclusion: Although mothers were sensitive to follow new breastfeeding recommendations, it had no beneficial impact on infant health in this society with traditional, intensive breastfeeding. There seems to be little reason to discourage local practices as long as there are no strong data justifying such a change.
Lupin sensitization and clinical allergy in food allergic children in Norway
Authors: Lindvik Helene , Holden Lise , Løvik Martinus , Cvancarova Milada , Halvorsen Ragnhild
Published: April 2008

Aim: The aim of the present pilot study was to investigate to what extent children in Norway sensitized to lupin had clinical lupin allergy, and to compare sensitization to lupin with sensitization to other legumes.

Methods: Thirty‐five children with food allergy referred to a national referral hospital were evaluated with skin prick test (SPT) and analysis of serum‐specific IgE to lupin, peanut, pea and soy. The children with positive SPTs to lupin were offered oral food challenges with lupin flour.

Results: Fifteen children (43%) had positive SPT and 17 children (49%) had serum‐specific IgE to lupin. Ten SPT‐positive children underwent oral food challenges and one experienced an allergic reaction to lupin flour. This child was one of six challenged children with IgE antibodies to peanut >15 kUA/L. There was a strong relationship between positive SPT to lupin flour and positive SPT to soy and between positive SPT to lupin and specific IgE to soy, pea and peanut.

Conclusions: Children with sensitization to lupin are not likely to have a clinical lupin allergy. Avoidance of lupin on the basis of lupin sensitization or peanut allergy would lead to unnecessarily strict diets. Food challenge is currently necessary to diagnose lupin allergy.
Catecholaminergic polymorphic ventricular tachycardia in a child: A case report
Authors: Garabedian Lara , Verryckt Ann , Panzer Joseph , Wolf Daniel De
Published: April 2008

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare arrythmogenic disease characterized by exercise – or stress – induced ventricular tachyarryhtmias, syncope, or sudden death, usually in the pediatric age group. Familial occurrence has been noted in about 30% of cases. Inheritance may be autosomal dominant or recessive, usually with high penetrance. The causative genes have been mapped to chromosome 1. Mutations of the cardiac ryanodine receptor gene (RyR2) have been identified in autosomal dominant pedigrees, while calsequestrin gene (CASQ2) mutations are seen in recessive cases.

Conclusion: Due to its potential lethal outcome, exclusion or confirmation of catecholaminergic polymorphic ventricular tachycardia in children with physical and emotional syncope is mandatory. We report a case of catecholaminergic polymorphic ventricular tachycardia in a three‐year‐old child only diagnosed by genetic mapping.
Assessment of the prevalence of microaspiration by gastric pepsin in the airway of ventilated children
Authors: Gopalareddy Vani , He Zhaoping , Soundar Sam , Bolling Laura , Shah Mansi , Penfil Scott , McCloskey John J , Mehta Devendra I
Published: April 2008

Aim: Mechanically ventilated patients are at risk for aspiration of gastric contents. The aim of this observational study was to determine the prevalence of micro‐aspiration in children with cuffed and uncuffed endotracheal (ET) tubes and with tracheostomies and to assess the effect of feeding status on aspiration. Micro‐aspiration was determined by measuring gastric pepsin in tracheal aspirates.

Methods: We studied 27 children on ventilators in paediatric intensive care unit (PICU) and 10 children undergoing elective surgeries for various indications. Tracheal aspirates were collected from children on ventilatory support in the intensive care unit during medically indicated suctioning and from the group of children undergoing elective surgery in the operation room. Pepsin was detected by enzymatic assay.

Results: Overall 70% of cases in PICU were positive for pepsin in at least one of the aspirates. Pepsin positivity was significantly lower in the cuffed group than in the uncuffed and tracheostomy groups. Tube feedings did not significantly influence the prevalence of pepsin positivity.

Conclusions: Measurement of gastric pepsin in tracheobronchial fluid is a sensitive tool to detect aspirations in mechanically ventilated children and to assess the efficacy of preventive measures in PICU settings.
Skin conductance compared to a combined behavioural and physiological pain measure in newborn infants
Authors: Eriksson Mats , Storm Hanne , Fremming Asbjörn , Schollin Jens
Published: April 2008

Aim: To assess the ability of galvanic skin response (GSR) to differentiate between tactile and painful stimulation in newborn infants, and to compare this with the ability of the premature infant pain profile (PIPP).

Methods: Thirty‐two healthy full‐term infants undergoing routine blood sampling were recruited. In a randomized order they were subjected to tactile and painful stimulation. The three GSR variables conductance baseline level, number of waves per second and mean amplitude of the waves were recorded together with the behavioural and physiological variables of PIPP.

Results: The GSR variables number of waves and amplitude of the waves increased more during painful stimulation than during tactile stimulation, as did also the PIPP score. Receiver operating characteristic curves analysis revealed no significant differences between the studied methods.

Conclusion: GSR can differentiate painful from tactile stimulation, but more research is needed to achieve a clinically useful application.
Association between exposure to environmental tobacco smoke (ETS) and breastfeeding behaviour
Authors: Chou Sze‐Yuan , Hsu Hua‐Hsuan , Kuo Hsien‐Hua , Kuo Hsien‐Wen
Published: April 2008

Aim: A cross‐sectional study was conducted to investigate the association between breastfeeding behaviour and exposure to environmental tobacco smoke (ETS).

Method: Questionnaires were collected from 552 women. Blood and urine specimens were taken from part of the population at the time of delivery. The study population was classified into two groups: those exposed to ETS and those unexposed, based on self‐reports from the subjects involved in the study. Cotinine levels in the urine and blood specimens were analysed by HPLC‐UV under strict quality control procedures.

Results: There was a significant negative association between the exposure to ETS at home or in the workplace and the prevalence of breastfeeding in each of the 6 months following delivery using multiple logistic regression adjusted for other covariates. The cotinine levels in the urine and blood were dose‐dependent, but not significantly so. However, women with lower cotinine levels had a higher probability of breastfeeding than those with higher levels.

Conclusion: Women who are exposed to ETS have a low likelihood of breastfeeding. It is necessary for the government to regulate ETS in public areas and confined spaces in order to reduce the levels of ETS that women are exposed to.
The rise of multiple births in Brazil
Authors: Homrich da Silva Clécio , Goldani Marcelo Zubaran , De Moura Silva Antônio Augusto , Agranonik Marilyn , Bettiol Heloísa , Barbieri Marco Antônio , Rona Roberto
Published: April 2008

Aim: The aim of this study was to assess the rise in multiple births and its influence on trends of low birth weight (LBW) rates in Porto Alegre, Brazil.

Methods: This is a registry‐based study of live births from 1994 to 2005 obtained from the national live birth information system. Chi‐square tests for trends were assessed for LBW and multiple birth rates. The impact of multiple births on LBW trends was assessed by sequential modelling, including year and further adjustment for multiple births. Risk factors for multiple births were assessed using the Poisson regression.

Results: A total of 263 252 live births were studied. The LBW rate increased from 9.70% to 9.88% (p < 0.001) and the multiple birth rate rose from 1.95% to 2.53% (p < 0.001). LBW rate increased among twins, from 57.14% to 63.46% (p = 0.001). The twin birth rate rose by 24.7%, while the rate of triplets or higher‐order increased by 150%. Multiple births may be responsible for 23.9% of the increase in the LBW rate over the period. Mothers with higher levels of schooling, older mothers and mothers delivering in private hospitals were more likely to deliver multiple births.

Conclusions: It seems that both the increase in multiple births and in the LBW among multiple births contributed to this rise in overall LBW rate.
Outcome in six children with mucopolysaccharidosis type IH, hurler syndrome, after haematopoietic stem cell transplantation (HSCT)
Authors: Malm Gunilla , Gustafsson Britt , Berglund Gunilla , Lindström Maria , Naess Karin , Borgström Birgit , Von Döbeln Ulrika , Ringdén Olle
Published: April 2008

Aim: To follow‐up six children with severe mucopolysaccharidosis type IH, Hurler syndrome, who were treated before 24 months of age with haematopoietic stem cell transplantation.

Methods: In Sweden, during the last 10‐year period, six consecutive children born with severe mucopolysaccharidoses type IH have been successfully transplanted using matched unrelated donors between the ages of 11 and 24 months (mean age 18 months). Three children received intravenous enzyme replacement therapy once a week, from diagnosis until engraftment of their bone marrow.

Result: Two children developed chimerism and a progressive increase in recipient cells and later received a successful re‐transplantation. One to two years after transplantation the children demonstrated some developmental delays in cognitive function. Latterly this was followed by normalization. Orthopaedic operations on the spine and hips and carpal tunnel syndrome were still required following transplantation. Cardiac valve involvement remained progressive in the children.

Conclusion: The outcome of six children in this study confirms that early haematopoietic stem cell transplantation in mucopolysaccharidosis type I, Hurler syndrome, preserves an affected child's mental ability. Consequently, it is essential that clinical recognition and early diagnosis take place, providing an additional challenge to paediatricians treating this condition.
Transplacental transport and tissue distribution of biotin in mice at midgestation
Authors: Taniguchi Ayumi , Watanabe Toshiaki
Published: April 2008

ABSTRACT  Biotin is a water‐soluble vitamin which functions as a coenzyme of carboxylases in glucose and amino acid metabolism and fatty acid synthesis. Biotin is also essential for maintaining reproductive function. Biotin deficiency during gestation induces cleft palate, micrognathia and limb hypoplasia in mouse fetuses at near term. Maternal biotin deficiency is severely tetatogenic in mammals. However, the relationship between abnormal morphogenesis and biotin deficiency is not sufficiently clear. This study was conducted to elucidate the mechanism of biotin transport from dams to embryos and the nutritional roles of biotin in ICR mice. Pregnant mice were given either a biotin‐deficient or biotin‐supplemented diet, and biotin and biotinidase activity were determined in dams and fetuses. It became evident that biotin was supplied from dams to growing embryos during morphogenesis. In particular, a large amount of biotin was transported to palates and mandibles on days 12–15 of gestation. The transportation of biotin to fetuses differed among fetal growth periods and organs. These results suggest that biotin is an essential nutrient and may play an important role in embryonic growth.
Adrenocorticotropic hormone affects nonapoptotic cell death of undifferentiated germ cells in the fetal mouse testis: In vivo study by exo utero transplantation of corticotropic tumor cells into embryos
Authors: Nimura Masayuki , Udagawa Jun , Otani Hiroki
Published: April 2008

ABSTRACT  Adrenocorticotropic hormone (ACTH) has been suggested to have possible roles in the fetal testes, one of the organs that express its specific receptors, melanocortin type 2 and 5 receptors (MC2R and MC5R), during the fetal period. We investigated the effect of ACTH on the cells in the testis cord of the fetal mouse testis by inducing ACTH‐secreting AtT20 tumor cells in mouse fetuses. We first identified that mouse testicular germ cells at embryonic day (E) 16.5 and E18.5 spermatogonia were entirely CDH1 (E‐cadherin)‐positive by immunohistochemistry. We next performed AtT20‐cell transplantation into the mouse fetus at E12.5, and analyzed ACTH effects on the development of fetal male mouse germ cells that express MC2R and MC5R at E16.5 and E18.5. The spermatogonia in the testis of AtT20‐implanted embryos exhibited morphological changes, including pyknotic nuclei and swollen cytoplasm. In the AtT20‐implanted embryos, the number of spermatogonia per unit area of the testis cord was significantly lower, but there were more pyknotic spermatogonia than in the controls. Single‐stranded DNA‐positive (apoptotic) and histone H3‐positive (mitotic) spermatogonia were rarely observed and their numbers did not significantly differ in the two groups. Anti‐Müllerian hormone (AMH)‐positive Sertoli cells, another cell type that constitutes the fetal testis cord but does not express MC2R or MC5R, showed no apparent morphological changes compared with controls, nor were their numbers in the two groups significantly different between the two groups. These results suggest that ACTH, via MC2R and/or MC5R, may be involved in the nonapoptotic cell death of fetal mouse spermatogonia that is observed during the normal perinatal period.
Structural birth defects associated with omphalocele and gastroschisis, Hawaii, 1986–2001
Authors: Forrester Mathias B. , Merz Ruth D.
Published: April 2008

ABSTRACT  There is limited information on the specific structural birth defects associated with the abdominal wall defects (AWD) omphalocele and gastroschisis, particularly which defects occur with the AWD at greater than expected rates (rates among all infants and fetuses with birth defects other than the AWD). Using data from a population‐based birth defects registry in Hawaii, this study calculated the rates for 48 specific structural birth defects among the AWD and compared these rates to the expected rates. There were 60 cases of omphalocele, 96 cases of gastroschisis, and 12 161 infants and fetuses with structural birth defects excluding the AWD among deliveries during 1986–2001. For omphalocele, higher than expected rates were found for 23 (47.9%) of the defects. These involved defects of a variety of organ systems. For gastroschisis, higher than expected rates were found for 8 (16.7%) of the defects, mainly neural tube defects (NTD) and specific defects of the orofacial and gastrointestinal system and the genital and urinary system. Both omphalocele and gastroschisis had elevated rates for NTD, intestinal atresia/stenosis, malrotation of intestines, obstructive genitourinary defects and limb reduction deformities. Certain specific structural birth defects occurred more often than expected with the AWD. The associated birth defects tended to vary between omphalocele and gastroschisis, although there were a few similarities. Due to the small number of cases, further research involving larger amounts of data are warranted.
Monochorionic twin fetuses showing a reversal of donor‐recipient phenotypes in severe twin–twin transfusion syndrome without oligo‐polyhydramnios sequence
Authors: Sunagawa Sorahiro , Kikuchi Akihiko , Kurihara Nobuyoshi , Hiroma Takehiko , Ono Kyoko , Miyachi Keiko , Takagi Kimiyo , Ogiso Yoshifumi , Nakamura Tomohiko
Published: April 2008

ABSTRACT  Antenatal sonographic diagnosis of twin–twin transfusion syndrome (TTTS) is based on findings of a twin oligo‐polyhydramnios sequence (TOPS) observed in monochorionic twin fetuses. However, TTTS can develop without a significant characteristic intertwin discordance in the amniotic fluid volumes. We report an uncommon form of TTTS without TOPS showing severe anemia in one twin and polycythemia in the other. Based on sonographic findings, it is considered that the recipient twin became the donor later in gestation, and vice versa. It is concluded therefore that even in the absence of TOPS, the possibility of severe TTTS with a suspected reversal of donor‐recipient phenotypes during pregnancy should not be excluded, and serial Doppler studies including the measurement of the middle cerebral artery peak systolic velocity should be routinely performed even in seemingly uncomplicated monochorionic twin fetuses without TOPS.
Large congenital melanocytic nevi presenting with lissencephaly with an absent corpus callosum
Authors: Takano Tomoyuki , Morimoto Mayumi , Sakaue Yuko , Takeuchi Yoshihiro , Aotani Hirofumi , Ohno Masaki
Published: April 2008

ABSTRACT  A neonatal case of provisional neurocutaneous melanosis presenting with lissencephaly is reported. Several congenital nevi were observed on the trunk and extremities of the infant, including a giant congenital hairy nevus over the skull. Brain magnetic resonance imaging revealed a marked ventricular dilatation with pachygyria and an absent corpus callosum; however, an injection of gadolinium did not demonstrate any enhanced lesions. Histopathological investigations by a brain biopsy showed a disorganized and anomalous embryonic cerebral architecture, suggesting lissencephaly. The detailed mechanism of this combined pathology is difficult to explain; however, a developmental disturbance was suggested to be present in both the neural crest cells and the neuroepithelial cells, resulting in the development of neurocutaneous melanosis accompanied with lissencephaly.
Cotylea (Polycladida): a cladistic analysis of morphology
Authors: Rawlinson Kate A. , Litvaitis Marian K.
Published: April 2008

Abstract. Polyclad flatworms are acoelomate bilaterians found in benthic communities worldwide, predominantly in marine environments. Current polyclad systematics is unstable, with two non‐concordant classification schemes resulting in a poor understanding of within‐group relationships. Here we present the first phylogenetic framework for the suborder Cotylea using a morphological matrix. Representatives of 34 genera distributed among all cotylean families (except four, excluded due to their dubious taxonomic status) were investigated. The number of families included ranges from a conservative eight to a revisionary 11. Outgroup analysis indicated that the suborder is monophyletic and defined by the presence of a ventral adhesive structure, a short posteriorly positioned vagina, and cement glands. Of the eight to 11 families included, we confirmed that three were monophyletic: Boniniidae, Prosthiostomidae, and Pseudocerotidae. Boniniidae was consistently recovered as the sister group to other Cotylea, based on the retention of the plesiomorphic Lang's vesicle. The clade consisting of Anonymus, Marcusia, and Pericelis is sister to the Boniniidae and the rest of the Cotylea. Above this clade there is little resolution at the base of the sister group. The Euryleptidae are found to be paraphyletic and give rise to the Pseudocerotidae. Neither classification scheme received unequivocal support. The intrafamilial relationships of the diverse Pseudocerotidae and Euryleptidae were examined. Color pattern characters (used for species identification) were highly homoplasious but increased cladogram resolution within genera. The monophyly of seven genera within the Pseudocerotidae and Euryleptidae was not supported and many genera showed no autapomorphies, highlighting the need for taxonomic revision of these families.
Larval development of the featherstar Aporometra wilsoni (Echinodermata: Crinoidea)
Authors: Haig Jodie A. , Rouse Greg W.
Published: April 2008

Abstract. Larval development of a small ovoviviparous comatulid crinoid, Aporometra wilsoni, was investigated using a population from South Australia. The genital pinnules of reproductive females each contain an ovary, within which are oocytes of various stages. Generally, one or more developing larvae lie outside the ovary, but within each pinnule. Larvae pass through “uniformly ciliated” and doliolaria stages before they exit the pinnule via the genital pore. The doliolariae lack the usual ciliary bands and are unable to swim. Doliolariae dissected from pinnules were followed through metamorphosis to the cystidean stage until the pentacrinoid larval stage. While previous reports on Aporometra have noted pentacrinoids attached to the female, virtually no pentacrinoids were found attached to any of the hundreds of adult females observed during this study. Females sampled from the mid‐reproductive season (September and October) were found to bear >2500 developing eggs and larvae at a time. It appears that emerging doliolariae fall from the female and attach to other substrates to complete development. Aporometra is classified in Notocrinida with the Antarctic crinoid Notocrinus. This classification is based in part on their supposedly homologous larval brooding. However, the reproductive mechanism in A. wilsoni is quite different from Notocrinus, calling into question their current status as sister taxa.
Age Structure and Growth of Degraded Populus euphratica Floodplain Forests in North‐west China and Perspectives for Their Recovery
Authors: Westermann Janneke , Zerbe Stefan , Eckstein Dieter
Published: April 2008

The Populus euphratica floodplain forests along the lower reaches of the Tarim River in continental‐arid Xinjiang (north‐west China) have been declining in recent decades as a result of dam constructions and the withdrawal of water from the river. Since 2000, controlled flooding has been carried out to counteract this process of degradation. However, the consequences of a changing water regime for the floodplain ecosystem are not yet sufficiently investigated. In 2004 we sampled a total of 150 P. euphratica trees along two transects at the middle and lower reaches of the Tarim River to compare the age structure and growth of these two tree populations. The anthropogenic drawdown of the groundwater table had no effect on the average growth of the trees at the lower reaches. However, tree growth abruptly increased after controlled flooding, thus showing distinct signs of recovery.