bluuebunny/crossref_metadata_2025 huggingface dataset:
Uniqueness in percolation theory
Authors: Meester R.W.J.
Published: April 2008

The possible uniqueness of the infinite cluster in percolation theory has been a subject of research for more then three decades. A number of important results have been proved in the last eight years and most of the question posed thirty years ago are answered nowadays. In this review paper, I shall give an account on the history of the subject plus recent developments. My goal is not only to mention the main results, but also to give some idea of the methods of proofs which are involved. I also discuss some applications and open problems.
Asymptotic confidence intervals for the length of the shortt under random censoring
Authors: Beirlant J. , Einmahl J. H. J.
Published: April 2008

A shortt of a one dimensional probability distribution is defined to be an interval which has at least probability t and minimal length. The length of a show and its obvious estimator are significant measures of scale of a distribution and the corresponding random sample, respectively. In this note a non‐parametric asymptotic confidence interval for the length of the (uniqueness is assumed) shortt is established in the random censorship from the right model. The estimator of the length of the shortt is based on the product‐limit (PL) estimator of the unknown distribution function. The proof of the result mainly follows from an appropriate combination of the Glivenko‐Cantelli theorem and the functional central limit theorem for the PL estimator.
Efficiency. of infinite dimensional M‐ estimators
Authors: van der Vaart A. W.
Published: April 2008

It is well‐known that maximum likelihood estimators are asymptotically normal with covariance equal to the inverse Fisher information in smooth, finite dimensional parametric models. Thus they are asymptotically efficient. A similar phenomenon has been observed for certain infinite dimensional parameter spaces. We give a simple proof of efficiency, starting from a theorem on asymptotic normality of infinite dimensional M‐estimators. The proof avoids the explicit calculation of the Fisher information. We also address Hadamard differentiability of the corresponding M‐functionals.
Asymptotic normality of the NPMLE of linear functionals for interval censored data, case 1
Authors: Huang J. , Wellner J. A.
Published: April 2008

We give a new proof of the asymptotic normality of a class of linear functionals of the nonparametric maximum likelihood estimator (NPMLE) of a distribution function with “case 1” interval censored data. In particular our proof simplifies the proof of asymptotic normality of the mean given in Groeneboom and Wellner (1992). The proof relies strongly on a rate of convergence result due to van de Geer (1993), and methods from empirical process theory.
On the estimation of the parameters for the Littlewood model in software reliability
Authors: Barendregt L. G. , van Pul M. C.
Published: April 2008

A very well‐known model in software reliability theory is that of Littlewood (1980). The (three) parameters in this model are usually estimated by means of the maximum likelihood method. The system of likelihood equations can have more than one solution. Only one of them will be consistent, however. In this paper we present a different, more analytical approach, exploiting the mathematical properties of the log‐likelihood function itself. Our belief is that the ideas and methods developed in this paper could also be of interest for statisticians working on the estimation of the parameters of the generalised Pareto distribution. For those more generally interested in maximum likelihood the paper provides a ‘practical case’, indicating how complex matters may become when only three parameters are involved. Moreover, readers not familiar with counting process theory and software reliability are given a first introduction.
Data features1
Authors: Davies P. L.
Published: April 2008

This article attempts to provide a formal framework for a data based inference which explicitly and consistently recognizes the approximate nature of probability models. It is based on the idea that a stochastic model is adequate if samples generated under the model are very much like the sample actually obtained. The formalization is based on the concept of data feature. Examples are given of applying the ideas to different areas of statistics including location‐scale models, densities, non‐parametric regression, interlaboratory test, auto‐regressive processes and the analysis of variance. The four cornerstones of the approach are direct comparison, approximation, weak topologies and parsimony. The approach is contrasted to that of much of conventional statistics many of whose concepts are pathologically discontinuous with respect to the topology of data analysis and common sense.
Constructive identification of the mixed proportional hazards model
Authors: Kortram R. A. , van Rooij A. C. M. , Lenstra A. J. , Ridder G.
Published: April 2008

We give a new proof of the identifiably of the MPH model. This proof is constructive: it is a recipe for constructing the triple—regression function, base‐line hazard, and distribution of the individual effect—from the observed cumulative distribution functions.

We then prove that the triples do not depend continuously on the observed cumulative distribution functions. Uniformly consistent estimators do not exist.

Finally we show that the MPH model is even identifiable from two‐sided censored observations. This proof is constructive, too.
Durations in Panel Data Subject to Attrition: A Note on Estimation in the Case of a Stock Sample1
Authors: van den Berg G. J. , Lindeboom M.
Published: April 2008

In the empirical analysis of unemployment durations or job durations, it is generally assumed that the stochastic processes underlying labour market behaviour and the behaviour concerning participation in a panel survey are independent. As a consequence, spells that are incomplete due to attrition can be treated as spells that are subjected to independent right censoring. However, if the assumption of independence is violated, i.e. if for example the probability of dropping out of the panel is related to the rate at which a job is found, then attrition may have to be modelled and estimated jointly with the unemployment duration distribution to avoid biased estimates of the rate at which individuals become employed. A way to model the joint dependence is by means of stochastically related unobserved determinants. We discuss some properties of these kinds of models and state conditions needed to estimate such models in the case of stock sampled duration data.
The transition from school to work in 1979–1987 in the Netherlands*
Authors: van Opstal R. , van de Pol F. J. R.
Published: April 2008

We analyze the early labour market experiences of the cohort born in the Netherlands around 1965. Some of them, who left school early, entered the labour market just before the economic crisis of the eighties; the others entered the labour market during the period of high unemployment. We concentrate on the time‐period between school‐leaving and entering the first job. The individual differences in these initial durations of non‐employment are analyzed by estimating hazard functions.
A smoothed maximum score estimator for the binary choice panel data model with an application to labour force participation
Authors: Charlier E. , Melenberg B. , van Soest A. H. O.
Published: April 2008

In a binary choice panel data model with individual effects and two time periods, Manski proposed the maximum score estimator based on a discontinuous objective function and proved its consistency under weak distributional assumptions. The rate of convergence is low (N1/3) and its limit distribution cannot easily be used for statistical inference. In this paper we apply the idea of Horowitz to smooth Manski's objective function. The resulting smoothed maximum score estimator is consistent and asymptotically normal with a rate of convergence that can be made arbitrarily close to N1/2, depending on the strength of the smoothness assumptions imposed. The estimator can be applied to panels with more than two time periods and to unbalanced panels. We apply the estimator to analyze labour force participation of married Dutch females.
Models for monthly penetrations with incomplete panel data*
Authors: Sikkel D. , Hoogendoorn A. W.
Published: April 2008

The purchase behaviour of consumers is observed in a panel during a month. The quantity of interest is the penetration of a product. The problem is that this quantity has to be estimated on the basis of incomplete data. For some or all respondents some weeks are missing. To this end the purchasing process is modeled with a variety of stochastic processes. The performance of some existing models is compared for penetrations of the complete population, but also for Bayesian estimates in subpopulations.
Industrial statistics and its recent contributions to total quality in the Netherlands
Authors: Does R. J. M. M. , Roes K. C. B.
Published: April 2008

The use of statistical methods in quality management has a long history. Most of the pioneers, such as Walter A. Shewhart and W. Edwards Deming, refer to themselves as statisticians. Statistical thinking in industry means that all work is a series of interconnected processes, that all processes show variation, and that a reduction in variation is the key for continuous improvement. In the statistical literature we find several approaches to achieve this: quality by inspection, quality by process control and quality by design. In this paper we give a survey of the contributions of Dutch statisticians during the last five years.
Recent Ph.D. Theses in the Netherlands
Authors: Koning R. H.
Published: April 2008

Statistica Neerlandica encourages the reporting on theses in probability, statistics, biometrics, econometrics, and operations research, submitted to Dutch universities. The main purpose of this section is to inform the reader briefly of the nature, the practical and theoretical importance, the methods used, and the results presented in recent theses.

Notes (not exceeding 300 words) should be sent to the column editor.
The Research of Wim Vervaat
Authors: O'Brien G. L.
Published: April 2008

This essay gives an outline of some of Wim Vervaat's innovative research ideas, especially those involving sup measures and capacities. These ideas were developed at his initiative in order to find satisfactory solutions to some limit problems in probability theory. The essay discusses the motivating questions and the role of sup measures and capacities in their solutions.
Large deviation principles and loglog laws for observation processes
Authors: O'Brien G. L. , Vervaat W.
Published: April 2008

Let (Xn, n ≥ 1) be an i.i.d. sequence of positive random variables with distribution function H. Let φH:={(n, Xn), n ≥ 1) be the associated observation process. We view φh as a measure on E:= [0, ∞) ∞ (0, φ] where φH (A) is the number of points of φH which lie in A. A family (Vs, s> 0) of transformations is defined on E in such a way that for suitable H the distributions of (VsφH, S > 0) satisfy a large deviation principle and that a related Strassen‐type law of the iterated logarithm also holds. Some consequent large deviation principles and loglog laws are derived for extreme values. Similar results are proved for φH replaced by certain planar Poisson processes.
Functional laws of the iterated logarithm for small increments of empirical processes
Authors: Deheuvels P.
Published: April 2008

LetF, denote the uniform empirical distribution based on the firstn ≥1 observations from an i.i.d. sequence of uniform (0, 1) random variables. We describe the almost sure limiting behavior of the sets of increment functions{Fn(t + hn.) ‐ Fn(t):0 ≤t ≤1 ‐ hn}, when{hn: n ≥1) is a nonincreasing sequence of constants such thatnhn/logn ←0.
Sanov meets Cramér again
Authors: Gerritse B.
Published: April 2008

We introduce a new method for proving large‐deviation principles (LDPs). This method amounts to “mixing” a collection of LDPs with a sequence of probability measures that obeys itself an LDP. As an illustration, we construct from empirical measures a sequence of capacity‐valued maps that can be considered as an indexed collection of LDPs. The index 1 coincides with Sanov's theorem. By taking a Poisson mixture we establish a new connection with Cramér's theorem.
Lattices of capacities, and related topologies1
Authors: Holwerda H. , Vervaat W.
Published: April 2008

Capacities are defined as set functions with regularity properties in terms of two general families K and G of ‘inner’ and ‘outer’ sets (K = compact sets, G= open sets in the standard case). The space C of all such capacities is a complete lattice with respect to its natural partial order. The lattice structure of C is studied in combination with the natural topology of C. Also some subspaces are investigated.
A nonparametric measure of spatial interaction in point patterns
Authors: van Lieshout M. N. M. , Baddeley A. J.
Published: April 2008

The strength and range of interpoint interactions in a spatial point process can be quantified by the function J = (1 ‐ G)/(1 ‐ F), where G is the nearest‐neighbour distance distribution function and F the empty space function of the process. J(r) is identically equal to 1 for a Poisson process; values of J(r) smaller or larger than 1 indicate clustering or regularity, respectively. We show that, for a large class of point processes, J(r) is constant for distances r greater than the range of spatial interaction. Hence both the range and type of interaction can be inferred from J without parametric model assumptions. It is also possible to evaluate J(r) explicitly for many point process models, so that J is also useful for parameter estimation. Various properties are derived, including the fact that the J function of the superposition of independent point processes is a weighted mean of the J functions of the individual processes. Estimators of J can be constructed from standard estimators of F and G. We compute estimates of J for several standard point pattern datasets and implement a Monte Carlo test for complete spatial randomness.
A simple measure of skewness
Authors: Tajuddin I. H.
Published: April 2008

Groeneveld (1986) in discussing the skewness for the Weibull family has pointed out the shortcomings of the classical measures of asymmetry—the standardized third moment and the Pearson measure of skewness. He has shown that a modified form of the Pearson measure b3= (μ‐m)/E|X‐m| portrays the skewness of Weibull family quite well. We give another competitive measure of skewness T that is easy to interpret and is based on conditional expectations. The proposed measure satisfies the desirable properties of a skewness measure.
On the asymptotic behaviour of the Stringer bound1
Authors: Pap G. , van Zuijlen M. C. A.
Published: April 2008

The Stringer bound is a widely used nonparametric 100(1 ‐α)% upper confidence bound for the fraction of errors in an accounting population. This bound has been found in practice to be rather conservative, but no rigorous mathematical proof of the correctness of the Stringer bound as an upper confidence bound is known and also no counterexamples are available. In a pioneering paper Bickel (1992) has given some fixed sample support to the bound's conservatism together with an asymptotic expansion in probability of the Stringer bound, which has led to his claim of the asymptotic conservatism of the Stringer bound. In the present paper we obtain expansions of arbitrary order of the coefficients in the Stringer bound. As a consequence we obtain Bickel's asymptotic expansion with probability 1 and we show that the asymptotic conservatism holds for confidence levels 1 ‐α, with α∈ (0,1/2]. It means that in general also in a finite sampling situation the Stringer bound does not necessarily have the right confidence level. Based on our expansions we propose a modified Stringer bound which has asymptotically precisely the right nominal confidence level. Finally, we discuss other consequences of the expansions of the Stringer bound such as a central limit theorem, a law of the iterated logarithm and the functional versions of them.
A new conditional specification of the bivariate Poisson conditionals distribution1
Authors: Wesolowski J.
Published: April 2008

The bivariate Poisson conditionals distribution is characterized by the form of one of the conditional distributions and one of the conditional expectations.
RECONSIDERING THE INVESTMENT–PROFIT NEXUS IN FINANCE‐LED ECONOMIES: AN ARDL‐BASED APPROACH
Authors: Van Treeck Till
Published: April 2008

A Post‐Keynesian growth model is developed, in which financial variables are explicitly taken into account. Variants of an investment function are estimated econometrically, applying the ARDL (auto‐regressive distributed lag)‐based approach proposed by Pesaran et al. (Journal of Applied Econometrics, 16 (3), pp. 289–326). The econometric results are discussed with respect to a remarkable phenomenon that can be observed for some important OECD countries since the early 1980s: accumulation has generally been declining while profit shares and rates have shown a tendency to rise. We concentrate on one potential explanation of this phenomenon, which is particularly relevant for the USA and relies on a high propensity to consume out of capital income.
Monocyte count is an underlying marker of lacunar subtype of hypertensive small vessel disease
Authors: Cortina M. Gomis , Campello A. Rodríguez , Conde J. Jiménez , Ois A. , Voustianiouk A. , Téllez M. J. , Cuadrado E. , Roquer J.
Published: April 2008

Background:  In the hypertensive small vessel disease (HSVD), it remains unclear why some patients develop lacunar infarcts (LIs) whilst others develop deep intracerebral hemorrhages (dICHs). Inflammation might be related to LI, and leukocyte and monocyte counts are regarded as an inflammatory marker of ischemic stroke.

Objective:  We investigated the relationship between leukocyte and monocyte counts determined in the first 24 h after stroke onset in HSVD patients.

Methods:  We prospectively studied 236 patients with first acute stroke because of HSVD (129 LI and 107 dICH). We analyzed demographic data, vascular risk factors, and white blood cell count subtypes obtained in the first 24 h after stroke.

Results:  The multivariate analysis showed that LI subtype of HSVD was correlated with hyperlipidemia (P < 0.0001), a higher monocyte count (P = 0.002), and showed a trend with current smoking (P = 0.051), whereas dICH subtype was correlated with low serum total cholesterol (P = 0.003), low serum triglycerides (P < 0.0001), and high neutrophil count (P = 0.050).

Conclusions:  In patients who developed HSVD‐related stroke, high monocyte count, current smoking, and hyperlipidemia are prothrombotic factors related to LI, whereas low cholesterol and triglyceride values are related to dICH. Monocyte count might be an inflammatory risk marker for the occlusion of small vessels in hypertensive patients.
EXPLICATION, EXPLANATION, AND HISTORY
Authors: HAMMER CARL
Published: April 2008

To date, no satisfactory account of the connection between natural‐scientific and historical explanation has been given, and philosophers seem to have largely given up on the problem. This paper is an attempt to resolve this old issue and to sort out and clarify some areas of historical explanation by developing and applying a method that will be called “pragmatic explication” involving the construction of definitions that are justified on pragmatic grounds. Explanations in general can be divided into “dynamic” and “static” explanations, which are those that essentially require relations across time and those that do not, respectively. The problem of assimilating historical explanations concerns dynamic explanation, so a general analysis of dynamic explanation that captures both the structure of natural‐scientific and historical explanation is offered. This is done in three stages: In the first stage, pragmatic explication is introduced and compared to other philosophical methods of explication. In the second stage pragmatic explication is used to tie together a series of definitions that are introduced in order to establish an account of explanation. This involves an investigation of the conditions that play the role in historiography that laws and statistical regularities play in the natural sciences. The essay argues that in the natural sciences, as well as in history, the model of explanation presented represents the aims and overarching structure of actual causal explanations offered in those disciplines. In the third stage the system arrived at in the preceding stage is filled in with conditions available to and relevant for historical inquiry. Further, the nature and treatment of causes in history and everyday life are explored and related to the system being proposed. This in turn makes room for a view connecting aspects of historical explanation and what we generally take to be causal relations.
Intracellular minerals and metal deposits in prokaryotes
Authors: EDWARDS K. J , BAZYLINSKI D. A
Published: April 2008

Thanks to the work of Terrance J. Beveridge and other pioneers in the field of metal–microbe interactions, prokaryotes are well known to sequester metals and other ions intracellularly in various forms. These forms range from poorly ordered deposits of metals to well‐ordered mineral crystals. Studies on well‐ordered crystalline structures have generally focused on intracellular organelles produced by magnetotactic bacteria that are ubiquitous in terrestrial and marine environments that precipitate Fe3O4 or Fe3S4, Fe‐bearing minerals that have magnetic properties and are enclosed in intracellular membranes. In contrast, studies on less‐well ordered minerals have focused on Fe‐, As‐, Mn‐, Au‐, Se‐ and Cd‐precipitates that occur intracellularly. The biological and environmental function of these particles remains a matter of debate.
A NOVEL APPROACH TO STUDIES OF PREHISTORIC EXPLOITATION OF STONE TOOL MATERIALS USING MATERIAL COMPOSITION, SURFACE MORPHOLOGY, MICROSTRUCTURE AND MECHANICAL PROPERTIES*
Authors: YONEKURA KAORU , HASEGAWA HIROYUKI , HOTTA ATSUSHI , SUZUKI TETSUYA
Published: April 2008

For a comprehensive understanding of material exploitation in prehistory, we applied advanced analytical methods to Japanese prehistoric stone tool materials. Compositions, surface morphologies, microstructures and mechanical properties of the primary lithic materials were analysed. As a result of the tests on actual Palaeolithic artefacts, preferential material selection was observed based on composition, structure and other physical properties of the materials. Homogeneous materials composed of a single type of mineral—α‐quartz—were intentionally selected for Palaeolithic tools regardless of the type of rock. These materials unexceptionally present higher hardness and strength. Moreover, materials composed of extremely fine crystal grains of ~0.1 µm in size with highest hardness and strength were selectively used for sharp‐edged blades. These results lead us to the conclusion that quantitative and objective analyses will give us precise information on prehistoric materials, which will enable us to make an analytical approach to the comprehension of prehistoric exploitation of stone materials. This could eventually complement the traditional interpretation of material exploitation based on conventional petrological classifications.
PROVENANCE OF ANCIENT TEXTILES—A PILOT STUDY EVALUATING THE STRONTIUM ISOTOPE SYSTEM IN WOOL*
Authors: FREI K. M. , FREI R. , MANNERING U. , GLEBA M. , NOSCH M. L. , LYNGSTRØM H.
Published: April 2008

Strontium isotopes are used in archaeology to reconstruct human and animal migration routes. We present results of a pilot study applying strontium isotope analyses to modern sheep hair as a basis for its potential use as a provenance tracer for ancient woollen textiles. Our hydrofluoric acid‐based, lipid soluble analytical protocol, also tested on a number of ancient textile fibres, allows for contamination‐free, low blank strontium isotope analysis of minimal amounts of archaeological material. 87Sr/86Sr ratios of decontaminated sheep hair agree well with the compositions of biologically available (soluble) strontium fractions from the respective feeding ground soils, a translatable requirement for any potentially successful provenance tracing applied to wool textiles.
THE ORIGIN AND GEOCHEMICAL CHARACTERIZATION OF RED OCHRES FROM THE TITO BUSTILLO AND MONTE CASTILLO CAVES (NORTHERN SPAIN)*
Authors: IRIARTE E. , FOYO A. , SÁNCHEZ M. A. , TOMILLO C. , SETIÉN J.
Published: April 2008

Ochres were the most common source materials for pigments used in Palaeolithic rock art paintings. This work analyses the petrographic and geochemical signatures of different ochre samples from outcrops inside Tito Bustillo Cave and the Monte Castillo Caves using the most common techniques (petrography, XRD, SEM–EDS and ICP–MS) in archaeological pigment characterization studies. The results obtained permit the identification and characterization of the different source ochre types and, furthermore, allow the establishment of mineralogical and geochemical proxies for the study of questions related to ochre characterization, formation processes and provenance.
A comfortable night out? Alcohol, drunkenness and inclusive town centres
Authors: Eldridge Adam , Roberts Marion
Published: April 2008

The Licensing Act (2003) was enacted in England and Wales against the backdrop of media concern about ‘binge Britain’ and violent town centres avoided by ‘social drinkers’. This paper responds to these concerns by asking how to create more inclusive urban centres at night. Findings from focus groups found it was not alcohol consumption or a reluctance to partake in urban life that was detracting residents. Using the notion of ‘comfort’, the paper instead reveals a strong desire for varied late‐night experiences ranging from quiet local venues, to active streets and live venues.
Space and the secure base in agoraphobia: a qualitative survey
Authors: Holmes Joshua
Published: April 2008

An important aspect of agoraphobia is a fear of being in crowded public spaces. This inherent spatiality means that it has aroused geographical interest. Feminist geographers have argued that the underlying dynamic of agoraphobia is the patriarchal structuring of public space. Using Attachment Theory, which draws on ideas from psychoanalysis and ethology, agoraphobia is conceptualised as a response to perceived threat in the absence of a ‘secure base’, represented by a known person or space. In an attempt to elicit the lived experience of agoraphobia, vignettes were constructed typifying aspects of agoraphobic experience. Participants (n=123) were recruited from Internet agoraphobia self‐help forums. Males experiencing agoraphobia (18) formed a significant minority of respondents. Using qualitative methodology, responses to these vignettes, as well as transcripts of parallel telephone interviews, were analysed. Participants’ responses were synthesised into a composite narrative, ‘Charlotte's Story’. The study suggests the central dichotomy in agoraphobia is not that between public and private space but between threat and security. Individuals experiencing agoraphobia feel secure when in space (a ‘secure base’) that is private, bounded, and where they feel sovereign and active. Threat arises in the absence of these conditions, exacerbated by the gaze of strangers, and is mitigated by the presence of a trusted companion. Further qualitative evidence supported feminist accounts of the fragility of the agoraphobic self, and suggested that self‐experience is intimately connected with the experience of space. This study extends previous geographical and psychological accounts of agoraphobic ‘life worlds’.
Crests on Cotton: “Souvenir” T‐Shirts and the Materiality of Remembrance Among the Kwakwaka'wakw of British Columbia
Authors: Glass Aaron
Published: April 2008

This essay examines the production and circulation of printed T‐shirts as “souvenirs” within Kwakwaka'wakw (Kwakiutl) communities in British Columbia. Like button blankets in larger Northwest Coast cultures of visual display, such shirts are unique material forms that facilitate individual memories for specific events, collective family and village commemorations, and flexible affiliations at varying levels of identification. Drawing anthropological attention to the materiality of clothing as it mediates social relations, I address a mundane—if hallmark—form of modernity as it is indigenized within a micro‐economy of First Nations gift exchanges, fund‐raisers, and thrift stores, where it visually enables both the remembrance of local events and the re‐membering of social groups.
Evolutionism and Historical Particularism at the St. Petersburg Museum of Anthropology and Ethnography
Authors: Kan Sergei
Published: April 2008

In the 1900s–1920s, Lev Shternberg played a major role in transforming the St. Petersburg Museum of Anthropology and Ethnography into Russia's most comprehensive ethnology museum and a popular site for visitors. As an anthropologist, Shternberg was committed to both a Boasian investigation of individual cultures (and intercultural relations) and classical evolutionism. Hence he believed that his museum had to include displays depicting distinct cultures and culture areas and a separate department illustrating “the evolution and typology of culture.” The article examines his work of putting the former part of this vision into practice and the reasons why the latter one failed.
Chemistry and Structure of Anion‐Deficient Perovskites with Translational Interfaces
Authors: Abakumov Artem M. , Hadermann Joke , Van Tendeloo Gustaaf , Antipov Evgeny V.
Published: April 2008

A general description and review is given of a new type of anion‐deficient perovskite‐based structure where the perovskite parent structure is fragmented by periodically spaced translational interfaces. These interfaces demonstrate properties similar to those of the crystallographic shear (CS) planes in the ReO3‐type oxides and can be considered to be CS planes in the perovskite framework that contains cations at the A positions. The building principles and chemical compositions of such CS structures will be discussed.
New Phase Transitions in Perovskite Oxides: BiFeO3, SrSnO3, and Pb(Fe2/3W1/3)1/2Ti1/2O3
Authors: Scott James F. , Palai Ratnakar , Kumar Ashok , Singh Manoj K. , Murari Nishit M. , Karan Naba K. , Katiyar Ram S.
Published: April 2008

This paper reports on two new aspects of oxide perovskites: the first part is devoted to new phase transitions, especially at high temperatures; multiferroics such as BiFeO3 and Pb–Fe–W–titanate are emphasized but nonmagnetic materials such as SrSnO3 are included. The work summarized on bismuth ferrite emphasizes its metal–insulator transition near 1200 K (atmospheric pressure) and 47 GPa (room temperature); that on SrSnO3 emphasizes order–disorder phase transitions; and that on lead–iron tungstate–titanate exhibits a classic second‐order ferroelectric phase transition, of which rather few are known in the literature. The second part of the paper presents a discussion of constant phase elements for oxide perovskite ceramics; this is a modern way of characterizing their dielectric relaxation, particularly near phase transition temperatures.
K/Na Ratio Dependence of the Electrical Properties of [(KxNa1−x)0.95Li0.05](Nb0.95Ta0.05)O3 Lead‐Free Ceramics
Authors: Wu Jiagang , Xiao Dingquan , Wang Yuanyu , Wu Lang , Jiang Yihang , Zhu Jianguo
Published: April 2008

[(KxNa1−x)0.95Li0.05](Nb0.95Ta0.05)O3 (KxNLNT) (x=0.40–0.60) lead‐free piezoelectric ceramics were prepared by conventional solid‐state sintering. The effects of K/Na ratio on the dielectric, piezoelectric, and ferroelectric properties of the KxNLNT ceramics were studied. The experimental results show that the electrical properties strongly depend on the K/Na ratio in the KxNLNT ceramics. The KxNLNT (x=0.42) ceramics exhibit enhanced properties (d33∼242 pC/N, kp∼45.7%, kt∼47%, Tc∼432°C, To−t=48°C, ɛr∼1040, tanδ∼2.0%, Pr∼26.4 μC/cm2, Ec∼10.3 kV/cm). Enhanced electrical properties of the KxNLNT (x=0.42) ceramics could be attributed to the polymorphic phase transition near room temperature. These results show that the KxNLNT (x=0.42) ceramic is a promising lead‐free piezoelectric material.
Preparation of Full‐Dense Pb(Zr,Ti)O3Ceramics by Aerosol Deposition
Authors: Miyoshi Tetsu
Published: April 2008

Full‐dense fine‐grained bulk Pb(Zr,Ti)O3(PZT) ceramics with a thicknesses of 300 μm were successfully obtained by aerosol deposition (AD) employing the starting powder subjected to an adequate pretreatment. It was found that formation of internal pores during the postdeposition firing treatment takes place in two different mechanisms on different scales. Residual carbons contained in the as‐deposited PZT ceramics are responsible for the formation of extra‐large pores, inducing severe distortion to the shape of the sample. On the other hand, trapped agglomerates in the as‐deposited PZT ceramics are responsible for the formation of intermediate pores. The revealed mechanisms are discussed with a focus on the positive/negative correlation between the pretreatment procedure of starting powders and the formation of internal pores.
Effect of Sc Substitution for Al on the Optical Properties of Transparent Ce:YSAG Ceramics
Authors: Feng Tao , Shi JianLin , Jin XiaoGang , Jiang DanYu
Published: April 2008

Transparent Ce:YAG (Ce:Y3Al5O12) and Ce:YSAG (Ce:Y3ScxAl5−xO12) ceramics have been successfully fabricated using Sc3+ to substitute for Al3+ in Ce:YAG. The effect of Sc substitution on the luminescent properties of Ce:YAG has been investigated. At the substitution level of 20 at.% of Sc3+ for Al3+, the emission intensity of Ce:YSAG is the highest. Meanwhile, the doping of Sc into Ce:YAG lattice broadened both the absorption and emission bands, which is believed to be due to the inhomogeneous broadening of the 5d energy level of Ce3+ caused by the Sc3+ substitution.
Comparative Electrical Behavior at Low and High Current of SnO2‐ and ZnO‐Based Varistors
Authors: Ramírez Miguel Angel , Bassi Welson , Parra Rodrigo , Bueno Paulo Roberto , Longo Elson , Varela Josê Arana
Published: April 2008

The complete I–V characteristics of SnO2‐based varistors, particularly of the Pianaro system SCNCr consisting in 98.9%SnO2+1%CoO+0.05%Nb2O5+0.05%Cr2O3, all in mol%, have been seldom reported in the literature. A comparative study at low and high currents of the nonohmic behavior of SCNCr‐ and ZnO‐based varistors (modified Matsuoka system) is proposed in this work. The SCNCr system showed higher nonlinearity coefficients in the whole range of measured current. The electrical breakdown field (Eb) was twice as high for the SCNCr system (5400 V/cm) than for the ZnO varistor (2600 V/cm) due to a smaller average grain size of the former (4.5 μm) with respect to the latter (8.5 μm). Nevertheless, we consider that another important factor responsible for the high Eb in the SCNCr system is the great number of electrically active interfaces (85%) as determined with electrostatic force microscopy (EFM). It was also established that the SCNCr system might be produced in disks of smaller dimensions than that of commercial ZnO‐based product, with a 5.0 cm−1 minimal area–volume (A/V) ratio. The SCNCr reached the saturation current in a short time because of the high resistivity of the grains, which is five times higher than that of the grains in ZnO‐based varistors.
Highly Ordered N‐Containing Mesoporous Silica from Carbothermal Reduction–Nitridation with the Nanocasting Procedure
Authors: Wang Minghui , Liu Qian , Wang Jiacheng , Xiu Tongping
Published: April 2008

Highly ordered N‐containing mesoporous silica materials with high specific surface area were prepared by heat treatment of the as‐synthesized mesoporous silica nanocasted with carbon in its channels in flowing N2 at high temperatures. This is the first time N2‐assisted carbothermal reduction–nitridation with nanocasting procedure has been used to prepare ordered mesoporous materials.
New diagnostic methods in dermatopathology: in vivo reflectance confocal microscopy
Authors: Ahlgrimm‐Siess Verena , Koller Silvia , Shabrawi‐Caelen Laila El , Hofmann‐Wellenhof Rainer , Kerl Helmut
Published: April 2008

Reflectance confocal microscopy is a new non‐invasive imaging technique which enables the visualization of upper skin layers in‐vivo at quasi‐histological resolution. Skin changes seen in confocal microscopy in Porokeratosis Mibelli and scabies infection are described in the following two cases.
Prevention of traumatic headache, dizziness and fatigue with creatine administration. A pilot study
Authors: Sakellaris George , Nasis George , Kotsiou Maria , Tamiolaki Maria , Charissis Giorgos , Evangeliou Athanasios
Published: April 2008

Aim: The complex pathobiology of traumatic brain injury (TBI) offers numerous targets for potential neuroprotective agents. We evaluate the clinical benefit after creatine (Cr) administration in children and adolescents

Methods: A prospective, randomized, comparative, open‐ labelled pilot study of the possible neuroprotective effect of Cr was carried out on 39 children and adolescents, aged between 1 and 18 years of age, with TBI. The Cr was administered for 6 months, at a dose of 0.4 g/kg in an oral suspension form every day. For categorical variables, we used the Chi‐square test to identify differences between controls and cases. Statistical significance was defined as a p‐value < 0.05 and not statistically significant if p‐value > 0.1.

Results: The administration of Cr to children and adolescents with TBI improved results in several parameters, including duration of post traumatic amnesia (PTA), duration of intubation, intensive care unit stay. Significant improvement was recorded in the categories of headache (p < 0.001), dizziness (p = 0.005) and fatigue (p < 0.001), aspects in all patients. No side effects were seen due to Cr administration.

Conclusion: More specific examinations including brain spectroscopy for in vivo evaluation of Cr can be done, in order to draw conclusions for the optimal duration and manner of Cr supply, as well as its possible role for the prevention of TBI complications, in double blind studies.
Maturation of oral feeding skills in preterm infants
Authors: Amaizu N , Shulman RJ , Schanler RJ , Lau C
Published: April 2008

Aim: Safe and successful oral feeding requires proper maturation of sucking, swallowing and respiration. We hypothesized that oral feeding difficulties result from different temporal development of the musculatures implicated in these functions.

Methods: Sixteen medically stable preterm infants (26 to 29 weeks gestation, GA) were recruited. Specific feeding skills were monitored as indirect markers for the maturational process of oral feeding musculatures: rate of milk intake (mL/min); percent milk leakage (lip seal); sucking stage, rate (#/s) and suction/expression ratio; suction amplitude (mmHg), rate and slope (mmHg/s); sucking/swallowing ratio; percent occurrence of swallows at specific phases of respiration. Coefficients of variation (COV) were used as indices of functional stability. Infants, born at 26/27‐ and 28/29‐week GA, were at similar postmenstrual ages (PMA) when taking 1–2 and 6–8 oral feedings per day.

Results: Over time, feeding efficiency and several skills improved, some decreased and others remained unchanged. Differences in COVs between the two GA groups demonstrated that, despite similar oral feeding outcomes, maturation levels of certain skills differed.

Conclusions: Components of sucking, swallowing, respiration and their coordinated activity matured at different times and rates. Differences in functional stability of particular outcomes confirm that maturation levels depend on infants' gestational rather than PMA.
Wheezy babies—wheezy adults? Review on long‐term outcome until adulthood after early childhood wheezing
Authors: Piippo‐Savolainen Eija , Korppi Matti
Published: April 2008

Population‐based birth cohort studies have documented that about 30% of children suffer from wheezing during respiratory infection before their third birthday. Recurrent wheezing is common in early childhood, but most patients outgrow their symptoms by school age. However, recent long‐term postbronchiolitis follow‐up studies from Sweden and Finland have revealed that asthma is present in about 40% of young adults and over half of the cases are relapses after many symptom‐free years.

In population studies, the principal predictors for later asthma have been parental asthma, recurrent wheezing, atopy and eosinophilia. In the Swedish postbronchiolitis study, atopic diathesis through the development of clinical atopy, and early passive smoking through bronchial hyper‐reactivity or later active smoking led to adult asthma. The Finnish postbronchiolitis follow‐up stressed early recurrence of wheezing, wheezing induced by less invasive viruses than respiratory syncytial virus (RSV), early‐life atopy and eosinophilia and parental asthma as predictors for adult asthma.

Conclusion: The majority of wheezing infants and children outgrow their symptoms by school age, but based on recent long‐term follow‐up studies, asthma relapses are common in young adults. These studies have highlighted parental asthma, maternal smoking and wheezing induced by other viruses than RSV as predictive factors for later asthma.
Radiographic follow‐up of community‐acquired pneumonia in children
Authors: Surén Pål , Try Kirsti , Eriksson Jan , Khoshnewiszadeh Behzad , Wathne Karl‐Olaf
Published: April 2008

Aim: To evaluate the value of radiographic follow‐up of community‐acquired pneumonia in children who are previously healthy.

Methods: Patient records for the years 2003 and 2004 at the Ullevål University Hospital in Oslo were reviewed, and a total of 245 children were selected for the study. Radiographs were evaluated by two paediatric radiologists independently.

Results: One hundred and thirty‐three patients had control radiographs, of which 106 were normal and 27 were abnormal. Only three of 27 patients with abnormal findings had further clinical problems that could be related to the pneumonia. Two of 106 with normal findings had further clinical problems, despite the normal control radiograph. Of the 112 without radiographic follow‐up, 10 had subsequent clinical problems, but most occurred within the first 4 weeks after discharge, before controls would have been scheduled.

There were five patients who may have benefited from controls. One relapse could theoretically have been prevented. Four patients were cases for whom the pneumonias were the first manifestations of chronic lung disease. Such patients may have some benefit from control radiographs, but only in terms of detecting the chronic disease at an earlier stage, not in altering the clinical course. Such modest benefits must be weighed against the consequences of providing follow‐up to a large number of healthy children, and making lots of abnormal findings with no clinical significance.

Conclusion: Control radiographs are not very valuable in children who are otherwise healthy.
The reliability of the Neonatal Oral‐Motor Assessment Scale
Authors: Da Costa Saakje P , Van Der Schans Cees P
Published: April 2008

Objectives: Sucking problems in preterm infants can be specified by means of visual observation. The Neonatal Oral‐Motor Assessment Scale (NOMAS) is the visual observation method most commonly used to assess the non‐nutritive sucking (NNS) and nutritive sucking (NS) skills of infants up to approximately 8 weeks postterm. During the first 2 min of a regular feeding the infant's sucking skill is assessed, either immediately or on video. Although NOMAS has been used since 1993, little is known about the method's reliability. The aim of our study was to determine the test‐retest and inter‐rater reliability of NOMAS.

Methods: The 75 infants included in this study were born at 26–36 weeks postmenstrual age (PMA). Four observers participated in the study. They were trained and certified to administer NOMAS in the Netherlands by M.M. Palmer between 2000 and 2002.

Results: We found the test‐retest agreement of NOMAS to be ‘fair’ to ‘almost perfect’ (Cohen's kappa [κ] between 0.33 and 0.94), whereas the inter‐rater agreement with respect to the diagnosis was ‘moderate’ to ‘substantial’ (Cohen's κ, between 0.40 and 0.65). As a diagnostic tool, however, the current version of NOMAS cannot be used for both full‐term and preterm infants. For a measuring instrument such as NOMAS, one should aim at reliability coefficients for inter‐rater and test‐retest agreement of at least 0.8. A Cohen's κ of 0.6 or less we find unacceptable. Nonetheless, by observing sucking and swallowing according to a protocol much useful information can be gathered about the development of an infant's sucking skills. For instance, whether the infant is able to co‐ordinate sucking and swallowing, whether the infant can maintain sucking, swallowing and breathing during the continuous phase and whether the infant is able to suck rhythmically with equally long bursts. In addition, NOMAS offers useful aids for intervention.

Conclusions: NOMAS should be re‐adjusted in order to improve inter‐rater agreement, and at the same time current insights into the development of sucking and swallowing should be incorporated in the method.
Mortality in childhood progressive encephalopathy from 1985 to 2004 in Oslo, Norway: a population‐based study
Authors: Strømme Petter , Magnus Per , Kanavin Øivind Juris , Rootwelt Terje , Woldseth Berit , Abdelnoor Michael
Published: April 2008

Aims: The aims were to estimate case fatality and survival rates, standardized mortality ratio (SMR), and independent prognostic factors for survival, in a population‐based cohort of progressive encephalopathy (PE) patients.

Methods: We divided onset of disease into neonatal and postneonatal groups and aetiology into metabolic (n = 55), neurodegenerative (n = 27) and HIV encephalopathy (n = 2) groups. Case fatality was the number of deaths divided by the number of patients. Cumulative survival probability at 10 years of follow‐up and independent risk factors for mortality were analyzed using the Kaplan‐Meier survival curve and the Cox model.

Results: Case fatality was 36.9% and the mean and median follow‐up times were 3109 and 2887 days. At 1 and 10 years, the cumulative probability of survival was 81% and 66%. Neonatal onset showed increased risk of death compared to postneonatal onset (RR 3.0; 95% CI 1.4–6.2). Metabolic aetiology showed increased risk of death compared to other aetiology (RR 1.25; 95% CI 1.10–1.46). The SMR of 37.7 for boys and 23.8 for girls was significantly increased (p < 0.001) compared to the total Norwegian population stratified by gender and age.

Conclusions: Children with PE showed a vast excess in mortality compared to the general population stratified by gender and age. Neonatal presentation and metabolic aetiology were the most significant factors for increased risk of death.
Amplitude‐integrated electroencephalographic changes in a newborn induced by overdose of morphine and corrected with naloxone
Authors: Niemarkt HJ , Halbertsma FJJ , Andriessen P , Bambang Oetomo S
Published: April 2008

The amplitude‐integrated electroencephalogram (aEEG) is a useful tool to assess brain function after perinatal asphyxia in term infants.

We report a full‐term newborn with moderate perinatal asphyxia, who accidentally received an overdose of morphine (5000 μg/kg). The overdose of morphine resulted in a clear and immediate change of aEEG background activity from a continuous (C) to discontinuous (DC) background pattern. After administration of naloxone, the background activity restored immediately to continuous background pattern. The aEEG was used to monitor the stepwise reduction in continuous naloxone infusion.

Conclusion: An overdose of morphine leads to clear and immediate changes in aEEG which restore after naloxone treatment. The aEEG can be used to monitor naloxone infusion.