bluuebunny/crossref_metadata_2025_split huggingface dataset:
Data structures with dynamical random transitions
Authors: Dombry C. , Guillotin‐Plantard N. , Pinçon B. , Schott R. 
Published: December 2005

AbstractWe present a (non‐standard) probabilistic analysis of dynamic data structures whose sizes are considered dynamic random walks. The basic operations (insertion, deletion, positive and negative queries, batched insertion, lazy deletion, etc.) are time‐dependent random variables. This model is a (small) step toward the analysis of these structures when the distribution of the set of histories is not uniform. As an illustration, we focus on list structures (linear lists, priority queues, and dictionaries) but the technique is applicable as well to more advanced data structures. © 2005 Wiley Periodicals, Inc. Random Struct. Alg., 2006
Asymptotics in Knuth's parking problem for caravans
Authors: Bertoin Jean , Miermont Grégory 
Published: December 2005

AbstractWe consider a generalized version of Knuth's parking problem, in which caravans consisting of a random number of cars arrive at random on the unit circle. Then each car turns clockwise until it finds a free space to park. Extending a recent work by Chassaing and Louchard Random Struct Algor 21(1) (2002), 76–119, we relate the asymptotics for the sizes of blocks formed by occupied spots with the dynamics of the additive coalescent. According to the behavior of the caravans' size tail distribution, several qualitatively different versions of the eternal additive coalescent are involved. © 2005 Wiley Periodicals, Inc. Random Struct. Alg., 2006
Slow mixing of Glauber dynamics for the hard‐core model on regular bipartite graphs
Authors: Galvin David , Tetali Prasad 
Published: December 2005

AbstractLet ∑ = (V,E) be a finite, d‐regular bipartite graph. For any λ > 0 let πλ be the probability measure on the independent sets of ∑ in which the set I is chosen with probability proportional to λ|I| (πλ is the hard‐core measure with activity λ on ∑). We study the Glauber dynamics, or single‐site update Markov chain, whose stationary distribution is πλ. We show that when λ is large enough (as a function of d and the expansion of subsets of single‐parity of V) then the convergence to stationarity is exponentially slow in |V(∑)|. In particular, if ∑ is the d‐dimensional hypercube {0,1}d we show that for values of λ tending to 0 as d grows, the convergence to stationarity is exponentially slow in the volume of the cube. The proof combines a conductance argument with combinatorial enumeration methods. © 2005 Wiley Periodicals, Inc. Random Struct. Alg., 2006
Minors in lifts of graphs
Authors: Drier Yotam , Linial Nathan 
Published: December 2005

AbstractWe study here lifts and random lifts of graphs, as defined by Amit and Linial (Combinatorica 22 (2002), 1–18). We consider the Hadwiger number η and the Hajós number σ of ℓ‐lifts of Kn and analyze their extremal as well as their typical values (that is, for random lifts). When ℓ = 2, we show that ${n \over 2} \leq \eta \leq n$, and random lifts achieve the lower bound (as n → ∞). For bigger values of ℓ, we show $\Omega({n \over {\sqrt{\log n}}}) \leq \eta \leq n\sqrt{\ell}$. We do not know how tight these bounds are, and in fact, the most interesting question that remains open is whether it is possible for η to be o(n). When ℓ < O(log n), almost every ℓ‐lift of Kn satisfies η = Θ(n) and for $\Omega(\log{n}) \leq \ell \leq n^{{1 \over 3} - \varepsilon}$, almost surely $\eta = \Theta({n\sqrt{\ell} \over {\sqrt{\log{n}}}})$. For bigger values of ℓ, $\Omega({n\sqrt{\ell} \over {\sqrt{\log{\ell}}}}) \leq \eta \leq n\sqrt{\ell}$ almost always. The Hajós number satisfies $\Omega(\sqrt{n}) \leq \sigma \leq n$, and random lifts achieve the lower bound for bounded ℓ and approach the upper bound when ℓ grows. © 2005 Wiley Periodicals, Inc. Random Struct. Alg., 2006
Some conditional correlation inequalities for percolation and related processes
Authors: van den Berg J. , Häggström O. , Kahn J. 
Published: December 2005

AbstractConsider ordinary bond percolation on a finite or countably infinite graph. Let s, t, a, and b be vertices. An earlier paper (J. Van den Berg and J. Kahn, Ann Probab 29 (2001), 123–126) proved the (nonintuitive) result that, conditioned on the event that there is no open path from s to t, the two events ”there is an open path from s to a” and “there is an open path from s to b” are positively correlated. In the present paper we further investigate and generalize the theorem of which this result was a consequence. This leads to results saying, informally, that, with the above conditioning, the open cluster of s is conditionally positively (self‐) associated and that it is conditionally negatively correlated with the open cluster of t.We also present analogues of some of our results for (a) random‐cluster measures and (b) directed percolation and contact processes and observe that the latter lead to improvements of some of the results in a paper of Belitsky et al. (Stoch Proc Appl 67 (1997), 213–225). © 2005 Wiley Periodicals, Inc. Random Struct. Alg., 2006
On random points in the unit disk
Authors: Ellis Robert B. , Jia Xingde , Yan Catherine 
Published: December 2005

AbstractLet n be a positive integer and λ > 0 a real number. Let Vn be a set of n points in the unit disk selected uniformly and independently at random. Define G(λ, n) to be the graph with vertex set Vn, in which two vertices are adjacent if and only if their Euclidean distance is at most λ. We call this graph a unit disk random graph. Let
$\lambda = c \sqrt {\ln n/n}$
and let X be the number of isolated points in G(λ, n). We prove that almost always X ∼ n when 0 ≤ c < 1. It is known that if $\lambda = \sqrt {(\ln n + \phi (n))/n}$
where ϕ(n) → ∞, then G(λ, n) is connected. By extending a method of Penrose, we show that under the same condition on λ, there exists a constant K such that the diameter of G(λ, n) is bounded above by K · 2/λ. Furthermore, with a new geometric construction, we show that when $\lambda = c \sqrt {\ln n/n}$
and c > 2.26164 …, the diameter of G(λ, n) is bounded by (4 + o(1))/λ; and we modify this construction to yield a function c(δ) > 0 such that the diameter is at most 2(1 + δ + o(1))/λ when c > c(δ). © 2005 Wiley Periodicals, Inc. Random Struct. Alg., 2006
A simple and general change‐point identifier
Authors: Riffenburgh R. H. , Cummins K. M. 
Published: December 2005

AbstractIn a not‐necessarily‐stationary time‐series, a Moving F statistic can identify points of change in the nature of the series model (the estimate of the underlying data‐generating process), in its parameters, in residual variability, or in any combination of these. In addition, it can uncover changes masked by a reduction in residual variability. Patterns in the forces giving rise to the data may often be perceived. To form the Moving F, a theory of the process or a regression method on a baseline sample estimates the series model and the residual mean square about it is calculated. This series model is extended past the baseline with residuals assumed to be normally distributed. The Moving F is calculated as the moving average of squared deviations about the series model in ratio to the baseline mean square. The Moving F crossing the critical F identifies a change in the series model, i.e. signals its presence and location. In our experience, this Moving F method is easier to use than other commonly employed change‐point identifiers (CUSUM, EWMA, data‐based bandwidth selection, MCMC) and has been found to work in several situations where some other identifiers fail. (MCMC is more general, but requires advanced statistical ability.) Examples given are monitored prostate specific antigen in a post‐treatment prostate cancer patient and detection of Harold Shipman's medical murders. Moving F is ‘simple and general’ in the sense of both simultaneously; we have not found another relatively simple method to be as general. Published in 2005 by John Wiley & Sons, Ltd.
ROC analysis for markers with mass at zero
Authors: Schisterman Enrique F. , Reiser Benjamin , Faraggi David 
Published: December 2005

AbstractThe receiver operating characteristic (ROC) curve and in particular the area under the curve (AUC) is commonly used to examine the discriminatory ability of diagnostic markers. Certain markers while basically continuous and non‐negative have a positive probability mass (spike) at the value zero. We discuss a flexible modelling approach to such data and contrast it with the standard non‐parametric approach. We show how the modelling approach can be extended to take account of the effect of explanatory variables. We motivate this problem and illustrate the modelling approach using data on the coronary calcium score, measured by electron beam tomography, which is a marker for atherosclerosis. Copyright © 2005 John Wiley & Sons, Ltd.
A modified test for small‐study effects in meta‐analyses of controlled trials with binary endpoints
Authors: Harbord Roger M. , Egger Matthias , Sterne Jonathan A. C. 
Published: December 2005

AbstractPublication bias and related bias in meta‐analysis is often examined by visually checking for asymmetry in funnel plots of treatment effect against its standard error. Formal statistical tests of funnel plot asymmetry have been proposed, but when applied to binary outcome data these can give false‐positive rates that are higher than the nominal level in some situations (large treatment effects, or few events per trial, or all trials of similar sizes). We develop a modified linear regression test for funnel plot asymmetry based on the efficient score and its variance, Fisher's information. The performance of this test is compared to the other proposed tests in simulation analyses based on the characteristics of published controlled trials. When there is little or no between‐trial heterogeneity, this modified test has a false‐positive rate close to the nominal level while maintaining similar power to the original linear regression test (‘Egger’ test). When the degree of between‐trial heterogeneity is large, none of the tests that have been proposed has uniformly good properties. Copyright © 2005 John Wiley & Sons, Ltd.
A Bayesian determination of threshold for identifying differentially expressed genes in microarray experiments
Authors: Chen Jie , Sarkar Sanat K. 
Published: December 2005

AbstractThe original definitions of false discovery rate (FDR) and false non‐discovery rate (FNR) can be understood as the frequentist risks of false rejections and false non‐rejections, respectively, conditional on the unknown parameter, while the Bayesian posterior FDR and posterior FNR are conditioned on the data. From a Bayesian point of view, it seems natural to take into account the uncertainties in both the parameter and the data. In this spirit, we propose averaging out the frequentist risks of false rejections and false non‐rejections with respect to some prior distribution of the parameters to obtain the average FDR (AFDR) and average FNR (AFNR), respectively. A linear combination of the AFDR and AFNR, called the average Bayes error rate (ABER), is considered as an overall risk. Some useful formulas for the AFDR, AFNR and ABER are developed for normal samples with hierarchical mixture priors. The idea of finding threshold values by minimizing the ABER or controlling the AFDR is illustrated using a gene expression data set. Simulation studies show that the proposed approaches are more powerful and robust than the widely used FDR method. Copyright © 2005 John Wiley & Sons, Ltd.
Repeated events survival models: the conditional frailty model
Authors: Box‐Steffensmeier Janet M. , De Boef Suzanna 
Published: December 2005

AbstractRepeated events processes are ubiquitous across a great range of important health, medical, and public policy applications, but models for these processes have serious limitations. Alternative estimators often produce different inferences concerning treatment effects due to bias and inefficiency. We recommend a robust strategy for the estimation of effects in medical treatments, social conditions, individual behaviours, and public policy programs in repeated events survival models under three common conditions: heterogeneity across individuals, dependence across the number of events, and both heterogeneity and event dependence. We compare several models for analysing recurrent event data that exhibit both heterogeneity and event dependence. The conditional frailty model best accounts for the various conditions of heterogeneity and event dependence by using a frailty term, stratification, and gap time formulation of the risk set. We examine the performance of recurrent event models that are commonly used in applied work using Monte Carlo simulations, and apply the findings to data on chronic granulomatous disease and cystic fibrosis. Copyright © 2005 John Wiley & Sons, Ltd.
Cumulative effects of air pollution on public health
Authors: Xia Yingcun , Tong Howell 
Published: December 2005

AbstractCumulative effect is an important way through which the pollutants affect public health. However, few existing dynamical models are well enough understood and documented to detect or quantify the cumulative effects and to answer pertinent questions posed by the World Health Organization (WHO): ‘Is there a threshold below which no effects of the pollutants on health are expected to occur in all people?’ and ‘What averaging period (time pattern) is the most relevant from the point of view of health?’. Using a new semi‐parametric time series modelling approach, which incorporates non‐linearity and latent cumulative variables, we show that the cumulative effects on health due to continual exposure to environmental pollutants can be very serious even at levels below the national ambient air quality standards of America (NAAQS). The situation is especially worrying for chronic sufferers. Our study suggests that different pollutants may require different cumulative periods (on average) to impact on health but they share a similar functional form in respect of their impact. We also suggest some possible revision of the ambient air quality standards. Copyright © 2005 John Wiley & Sons, Ltd.
The analysis of contingency tables with ordinal data: an application to monitoring antibiotic resistance
Authors: Bonetto C. , Giannerini S. , Giovagnoli A. 
Published: December 2005

AbstractRationalization of antibiotic therapy in the management of infectious diseases is helped by a knowledge of the patterns of sensitivity and resistance of bacteria to antibiotics and their possible changes both in time and from one hospital unit to another. In this paper we present the results regarding the sensitivities of several groups of bacteria and different Units of the S.Orsola‐Malpighi Hospital of Bologna in the period 1995–1997. We apply recent methods of analysis of ordinal contingency tables that rely on stochastic ordering of the rows to test the assumption that a decrease (or increase) in sensitivity of bacteria to specific antibiotics has taken place against the alternative that no such thing has happened. In most cases the results seem to indicate an increase in sensitivity rather than what was expected, namely the opposite. Copyright © 2005 John Wiley & Sons, Ltd.
Survival analysis using auxiliary variables via non‐parametric multiple imputation
Authors: Hsu Chiu‐Hsieh , Taylor Jeremy M. G. , Murray Susan , Commenges Daniel 
Published: December 2005

AbstractWe develop an approach, based on multiple imputation, that estimates the marginal survival distribution in survival analysis using auxiliary variables to recover information for censored observations. To conduct the imputation, we use two working survival models to define a nearest neighbour imputing risk set. One model is for the event times and the other for the censoring times. Based on the imputing risk set, two non‐parametric multiple imputation methods are considered: risk set imputation, and Kaplan–Meier imputation. For both methods a future event or censoring time is imputed for each censored observation. With a categorical auxiliary variable, we show that with a large number of imputes the estimates from the Kaplan–Meier imputation method correspond to the weighted Kaplan–Meier estimator. We also show that the Kaplan–Meier imputation method is robust to mis‐specification of either one of the two working models. In a simulation study with time independent and time‐dependent auxiliary variables, we compare the multiple imputation approaches with an inverse probability of censoring weighted method. We show that all approaches can reduce bias due to dependent censoring and improve the efficiency. We apply the approaches to AIDS clinical trial data comparing ZDV and placebo, in which CD4 count is the time‐dependent auxiliary variable. Copyright © 2005 John Wiley & Sons, Ltd.
Bias reduction in effectiveness analyses of longitudinal ordinal doses with a mixed‐effects propensity adjustment
Authors: Leon Andrew C. , Hedeker Donald , Teres Jedediah J. 
Published: December 2005

AbstractA mixed‐effects propensity adjustment is described that can reduce bias in longitudinal studies involving non‐equivalent comparison groups. There are two stages in this data analytic strategy. First, a model of propensity for treatment intensity examines variables that distinguish among subjects who receive various ordered doses of treatment across time using mixed‐effects ordinal logistic regression. Second, the effectiveness model examines multiple times until recurrence to compare the ordered doses using a mixed‐effects grouped‐time survival model. Effectiveness analyses are initially stratified by propensity quintile. Then the quintile‐specific results are pooled, assuming that there is not a propensity × treatment interaction. A Monte Carlo simulation study compares bias reduction in fully specified propensity model relative to misspecified models. In addition, type I error rate and statistical power are examined. The approach is illustrated by applying it to a longitudinal, observational study of maintenance treatment of major depression. Copyright © 2005 John Wiley & Sons, Ltd.
Maillard reaction product‐rich food impair cell proliferation and induce cell death in vitro
Authors: Bartling Babett , Rehbein Grit , Somoza Veronika , Silber Rolf‐Edgar , Simm Andreas 
Published: December 2005

AbstractMaillard reaction products (MRPs) and advanced glycation end‐products (AGEs) correspond to modified protein derivatives that are initially generated by non‐enzymatic glycation between amino acids and reducing sugars in heat‐treated foods and in vivo, respectively. Because lung tissue highly expresses the receptor for advanced glycation end‐products (RAGE), we studied the impact of MRP/AGE‐rich foods like bread crust (BC) and coffee extract (CE) on the proliferation and cell death induction using lung epithelial (H358) cells. Here, we showed that CE impairs the proliferation and viability of H358 cells at much higher extent than BC does. Particularly cell death induced by CE showed a concentration‐dependent shift from apoptotic to necrotic features as estimated by caspase activation, phosphatidylserine exposure, leakage of the outer membrane, mitochondrial dysfunction and stress kinase activation. Moreover, CE at higher dose triggered the generation of reactive oxygen species thereby mediating caspase inhibition. Non‐toxic concentrations of both foods only impaired the proliferation associated with an increased amount of cells in the S/G2 phase of the cell cycle, which did not depend on the over‐expression of RAGE. From our data we conclude that MRP/AGE‐rich foods mediate antiproliferative effects at moderate concentrations that might be important in physiological conditions like cancer prevention but contributes to cell death at higher levels in vitro.
NFκB: cell survival or cell death?
Authors: Strozyk Elwira , Kulms Dagmar 
Published: December 2005

AbstractThe present review outlines that the different pathways and components that may influence NFκB, to convert it from an inhibitor of apoptosis into a promoter of apoptosis, are quite versatile. As a consequence inhibition of the NFκB as a global concept to fight cancer should be reconsidered, although of course it seems reasonable for many incidences. Conclusively, cancer therapy can not be generalized but requires individual treatment.
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Efficient Designs for Powering Microscale Devices with Nanoscale Biomolecular Motors
Authors: Lin Chih‐Ting , Kao Ming‐Tse , Kurabayashi Katsuo , Meyhöfer Edgar 
Published: December 2005

AbstractCurrent MEMS and microfluidic designs require external power sources and actuators, which principally limit such technology. To overcome these limitations, we have developed a number of microfluidic systems into which we can seamlessly integrate a biomolecular motor, kinesin, that transports microtubules by extracting chemical energy from its aqueous working environment. Here we establish that our microfabricated structures, the self‐assembly of the bio‐derived transducer, and guided, unidirectional transport of microtubules are ideally suited to create engineered arrays for efficiently powering nano‐ and microscale devices.
Nanostructures of Sn and Their Enhanced, Shape‐Dependent Superconducting Properties
Authors: Hsu Yung‐Jung , Lu Shih‐Yuan , Lin Yi‐Feng 
Published: December 2005

AbstractA noncatalytic and template‐free vapor transport process was developed to make possible simultaneous growth of single‐crystalline tin nanowires, nanosquares, nanodisks, and polycrystalline nanoparticles. The formation of such a rich variety of morphologies in a single growth experiment can be attributed to variations in the growth rate among different crystallographic planes when employing the vapor–solid growth mechanism. Structural characterization with high‐resolution transmission electron microscopy reveals a preferential growth direction of [100] in Sn nanowires, nanosquares, and nanodisks. Shape‐dependent superconducting properties are observed. These four types of Sn nanostructures all show typical diamagnetic behavior in magnetization measurements, with the three anisotropically shaped nanostructures (nanowires, nanosquares, and nanodisks) showing one order of magnitude enhancement in the working magnetic field ranges for superconductivity, compared to bulk Sn and Sn nanoparticles. The magnetic field range is broadest for nanowires, followed by nanodisks, nanosquares, and nanoparticles.
Golden face: Cultural reciprocity in the articulation of mainland Chinese social structure
Authors: Lewis Hugh M. 
Published: December 2005

AbstractThe informal Chinese system of “face,” or dynamic, open‐ended networks of reciprocal social relations and transactions, is at the core of the everyday construction of contemporary Chinese social realities. Implicit rules guiding behavior in these networks regulate social relations and provide a familial sense of symbolic order and behavioral purpose to the Chinese world. If one is to endeavor any long‐term venture in China, for whatever constructive purposes, one must eventually come to terms with and even learn to negotiate this system of face with whomever one deals. © 2006 Wiley Periodicals, Inc.
Life and times of a Danish entrepreneur: Lessons for today's Russian market
Authors: Holden Nigel 
Published: December 2005

AbstractHarald Schou‐Kjeldsen first went to Russia as a young Danish diplomat from 1915 to 1919 and lived there again—there being, of course, Soviet Russia by that point— from 1922 to 1934. During this time, he ran various import‐export businesses and notably set up a button factory, employing at its peak some 350 workers. Schou‐Kjeldsen's life in the early Soviet Union provides a remarkable picture of how Stalinism stifled his business activities. Schou‐Kjeldsen, a resourceful entrepreneur in an adversarial business environment, has a special claim as a role model for foreign businesspeople operating in the not entirely dissimilar conditions of post‐Soviet Russia today. © 2006 Wiley Periodicals, Inc.