bluuebunny/crossref_metadata_2025_split huggingface dataset:
Robust non‐parametric one‐sample tests for the analysis of recurrent events
Authors: Rebora Paola , Galimberti Stefania , Valsecchi Maria Grazia 
Published: December 2010

AbstractOne‐sample non‐parametric tests are proposed here for inference on recurring events. The focus is on the marginal mean function of events and the basis for inference is the standardized distance between the observed and the expected number of events under a specified reference rate. Different weights are considered in order to account for various types of alternative hypotheses on the mean function of the recurrent events process. A robust version and a stratified version of the test are also proposed. The performance of these tests was investigated through simulation studies under various underlying event generation processes, such as homogeneous and nonhomogeneous Poisson processes, autoregressive and renewal processes, with and without frailty effects. The robust versions of the test have been shown to be suitable in a wide variety of event generating processes. The motivating context is a study on gene therapy in a very rare immunodeficiency in children, where a major end‐point is the recurrence of severe infections. Robust non‐parametric one‐sample tests for recurrent events can be useful to assess efficacy and especially safety in non‐randomized studies or in epidemiological studies for comparison with a standard population. Copyright © 2010 John Wiley & Sons, Ltd.
Correcting for misclassification for a monotone disease process with an application in dental research
Authors: García‐Zattera M. J. , Mutsvari T. , Jara A. , Declerck D. , Lesaffre E. 
Published: December 2010

AbstractMotivated by a longitudinal oral health study, we evaluate the performance of binary Markov models in which the response variable is subject to an unconstrained misclassification process and follows a monotone or progressive behavior. Theoretical and empirical arguments show that the simple version of the model can be used to estimate the prevalence, incidences, and misclassification parameters without the need of external information and that the incidence estimators associated with the model outperformed approaches previously proposed in the literature. We propose an extension of the simple version of the binary Markov model to describe the relationship between the covariates and the prevalence and incidence allowing for different classifiers. We implemented a Bayesian version of the extended model and show that, under the settings of our motivating example, the parameters can be estimated without any external information. Finally, the analyses of the motivating problem are presented. Copyright © 2010 John Wiley & Sons, Ltd.
Simultaneous confidence bounds for relative risks in multiple comparisons to control
Authors: Klingenberg B. 
Published: December 2010

AbstractWe discuss the construction of asymptotic simultaneous upper confidence limits that jointly bound relative risks formed by comparing several treatments to a control. Motivated by a vaccine study, we investigate the performance of several methods under such settings. Inverting the minimum of score statistics, together with estimating the correlation matrix of these statistics under the null gives simultaneous coverage rates closest to the nominal level. In typical settings of vaccine studies, this method proves to be the most powerful of the ones considered, but computationally simpler alternatives are also worth exploring when the number of comparisons is large. Simultaneous lower and two‐sided confidence intervals are also considered. All procedures can be implemented and evaluated using freely available and general R code. Copyright © 2010 John Wiley & Sons, Ltd.
Summary ROC curve based on a weighted Youden index for selecting an optimal cutpoint in meta‐analysis of diagnostic accuracy
Authors: Rücker Gerta , Schumacher Martin 
Published: December 2010

AbstractEstablished approaches for analyzing meta‐analyses of diagnostic accuracy model the bivariate distribution of the observed pairs of specificity Sp and sensitivity Se, thus accounting for across‐study correlation. However, it is still a matter of debate how to define a summary ROC (SROC) curve. It was recently pointed out that the SROC curve is in principle unidentifiable if only one (Sp, Se) pair per study is known. We evaluate an alternative approach, modeling the study‐specific ROC curves based on the assumption of linearity in logit space. A setting is considered in which the pair (Sp, Se) that is selected for publication in a particular study maximizes a weighted Youden index λSe+(1−λ)Sp with a given weight λ.This leads to a fixed slope (1−λ)/λ of the ROC curve in (1−Sp, Se), equivalent to a slope of (1−λ)Sp(1−Sp)/(λSe(1−Se)) for the corresponding straight line in logit space. While the slope depends on the variance ratio of the underlying distributions, the intercept is a function of the mean difference. Our approach leads in a natural way to a new, model‐based proposal for a summary ROC curve. It is illustrated using an example from the literature. Copyright © 2010 John Wiley & Sons, Ltd.
A semiparametric estimator of survival for doubly truncated data
Authors: Moreira Carla , de Uña‐Álvarez Jacobo 
Published: December 2010

AbstractDoubly truncated data are often encountered in the analysis of survival times, when the sample reduces to those individuals with terminating event falling on a given observational window. In this paper we assume that some information about the bivariate distribution function (df) of the truncation times is available. More specifically, we represent this information by means of a parametric model for the joint df of the truncation times. Under this assumption, a new semiparametric estimator of the lifetime df is derived. We obtain asymptotic results for the new estimator, and we show in simulations that it may be more efficient than the Efron–Petrosian nonparametric maximum likelihood estimator. Data on the age at diagnosis of childhood cancer in North Portugal are analyzed with the new method. Copyright © 2010 John Wiley & Sons, Ltd.
Frequentist performance of Bayesian inference with response‐adaptive designs
Authors: Lecoutre Bruno , Derzko Gérard , ElQasyr Khadija 
Published: December 2010

AbstractIn controlled clinical trials, where minimizing treatment failures is crucial, response‐adaptive designs are attractive competitors to 1:1 randomized designs for comparing the success rates ϕ1and ϕ2of two treatments. In these designs each new treatment assignment depends on previous outcomes through some predefined rule. Here Play‐The‐Winner (PW), Randomized Play‐The‐Winner (RPW), Drop‐The‐Loser, Generalized Drop‐the‐Loser and Doubly adaptive Biased Coin Designs are considered for new treatment assignments. As frequentist inference relies on complex sampling distributions in those designs, we investigate how Bayesian inference, based on two independent Beta prior distributions, performs from a frequentist point‐of‐view. Performance is assessed through coverage probabilities of interval estimation procedures, power and minimization of failure count. It is shown that Bayesian inference can be favorably compared to frequentist procedures where the latter are available. The power of response‐adaptive designs is generally very close to the power of 1:1 randomized design. However, failure count savings are generally small, except for the PW and Doubly adaptive Biased Coin designs in particular ranges of the true success rates. The RPW assignment rule has the worst performance, while PW, Generalized Drop‐the‐Loser or Doubly adaptive Biased Coin Designs may outperform other designs depending on different particular ranges of the true success rates. Copyright © 2010 John Wiley & Sons, Ltd.
Meta‐analysis of diagnostic test data: A bivariate Bayesian modeling approach
Authors: Verde Pablo E. 
Published: December 2010

AbstractIn the last decades, the amount of published results on clinical diagnostic tests has expanded very rapidly. The counterpart to this development has been the formal evaluation and synthesis of diagnostic results. However, published results present substantial heterogeneity and they can be regarded as so far removed from the classical domain of meta‐analysis, that they can provide a rather severe test of classical statistical methods. Recently, bivariate random effects meta‐analytic methods, which model the pairs of sensitivities and specificities, have been presented from the classical point of view. In this work a bivariate Bayesian modeling approach is presented. This approach substantially extends the scope of classical bivariate methods by allowing the structural distribution of the random effects to depend on multiple sources of variability. Meta‐analysis is summarized by the predictive posterior distributions for sensitivity and specificity. This new approach allows, also, to perform substantial model checking, model diagnostic and model selection. Statistical computations are implemented in the public domain statistical software (WinBUGS and R) and illustrated with real data examples. Copyright © 2010 John Wiley & Sons, Ltd.
Endoscopic placement of a new short‐term biodegradable pancreatic and biliary stent in an animal model: a preliminary feasibility study (with videos)
Authors: Itoi Takao , Kasuya Kazuhiko , Abe Yuta , Isayama Hiroyuki 
Published: December 2010

AbstractBackground and purposeRecently, biodegradable pancreatic stents have been designed and placed in vivo and in vitro. The aim of this study is to investigate the feasibility of endoscopic stenting using the novel, braided, self‐expandable, biodegradable, pancreatic and biliary stent in a pig model.MethodsA braided, self‐expandable, biodegradable stent was endoscopically placed into the pancreatic duct and bile duct in 4 pigs. Eventually, necropsy was performed to evaluate the stent placement after the procedure.ResultsPancreatic and biliary stents were successfully inserted and easily deployed across the papilla into the main pancreatic duct and bile duct, respectively, in all the animals under endoscopic and fluoroscopic guidance. Necropsy performed immediate following stent placement, found that stents had been placed across the papilla and stent expansion had occurred in all cases.ConclusionsAlthough this stent is not radiopaque and the number of cases was small in this experimental study, endoscopic stenting using this novel, braided, self‐expandable, biodegradable, pancreatic and biliary stent was feasible in the pig model. Further animal studies to evaluate the short‐term patency, tissue reactivity and degradability of the stents are warranted.
Toxic response caused by a misfolding variant of the mitochondrial protein short‐chain acyl‐CoA dehydrogenase
Authors: Schmidt Stinne P. , Corydon Thomas J. , Pedersen Christina B. , Vang Søren , Palmfeldt Johan , Stenbroen Vibeke , Wanders Ronald J. A. , Ruiter Jos P. N. , Gregersen Niels 
Published: December 2010

AbstractBackgroundVariations in the gene ACADS, encoding the mitochondrial protein short‐chain acyl CoA‐dehydrogenase (SCAD), have been observed in individuals with clinical symptoms. The phenotype of SCAD deficiency (SCADD) is very heterogeneous, ranging from asymptomatic to severe, without a clear genotype–phenotype correlation, which suggests a multifactorial disorder. The pathophysiological relevance of the genetic variations in the SCAD gene is therefore disputed, and has not yet been elucidated, which is an important step in the investigation of SCADD etiology.AimTo determine whether the disease‐associated misfolding variant of SCAD protein, p.Arg107Cys, disturbs mitochondrial function.MethodsWe have developed a cell model system, stably expressing either the SCAD wild‐type protein or the misfolding SCAD variant protein, p.Arg107Cys (c.319 C > T). The model system was used for investigation of SCAD with respect to expression, degree of misfolding, and enzymatic SCAD activity. Furthermore, cell proliferation and expression of selected stress response genes were investigated as well as proteomic analysis of mitochondria‐enriched extracts in order to study the consequences of p.Arg107Cys protein expression using a global approach.ConclusionsWe found that expression of the p.Arg107Cys variant SCAD protein gives rise to inactive misfolded protein species, eliciting a mild toxic response manifested though a decreased proliferation rate and oxidative stress, as shown by an increased demand for the mitochondrial antioxidant SOD2. In addition, we found markers of apoptotic activity in the p.Arg107Cys expressing cells, which points to a possible pathophysiological role of this variant protein.
Early Complications of Volar Plating of Distal Radius Fractures and Their Relationship to Surgeon Experience
Authors: Ward Christina M. , Kuhl Taften L. , Adams Brian D. 
Published: December 2010

Background Fractures of the distal radius are among the most common fractures in adults. Recently, there has been a trend towards open reduction and internal fixation of these fractures through a volar approach. The purpose of this study was to assess the early complications of volar locking plate fixation of distal radius fractures with an emphasis on defining the relationship between surgeon experience and incidence of complications. Materials and Methods Following IRB approval, we conducted a retrospective chart review of the initial 96 distal radius fractures (92 patients) treated by open reduction and internal fixation of distal radius fracture using a volar locked plate. Our outcome measurements were incidence of postoperative complications and radiographic loss of reduction. Results Twenty-two complications occurred in 21 patients. Of these, five complications (5%) required surgical treatment or hospitalization. Seventeen complications (18%) required no surgical intervention or hospitalization. Transient nerve dysfunction was the most common complication, accounting for 12 of 22 complications. The first 30 patients experienced significantly more complications than those treated later in the series ( p=0.03). There was a trend towards increased incidence of complications in cases where more than 10 days elapsed between injury and surgery or where supplementary Kirschner wire fixation was used. There was no correlation between patient age, sex, severity of fracture, or presence of ulnar styloid fracture and the development of complications or loss of reduction. Discussion The incidence of complications decreased significantly with increased surgeon experience, suggesting that many of these early complications are avoidable.
Ectopic splenic nodules in the olive baboon (Papio cynocephalus anubis)
Authors: Jeneby M.M. , Langoi D. , Mwenda J.M. , D. Chai 
Published: December 2010

Abstract:Post‐mortem evaluation of a female sub‐adult olive baboon (Papio cynocephalus anubis) revealed a case of ectopic spleen anomaly. Three spherical masses characterized the spleen anomaly. The splenic nodules were located on the left upper quadrant of the stomach, at the distal end of the pancreas. The anterior nodule measures 1.2 cm, the middle nodule 1.9 cm and the posterior nodule 1.3 cm in diameter. Normal spleen was not observed in this case. All the three ectopic splenic nodules showed normal histological architecture. A case of ectopic splenic nodules in baboon is important in that the spleen malformation can readily be mistaken for a pathological process.
How do economic crises impact firm boundaries?
Authors: Foss Kirsten 
Published: December 2010

AbstractHow economic crises impact the boundaries of firms has been offered virtually no attention in the literature on the theory of the firm. I review the best‐known theories of the firm and identify the variables that matter for the explanation of firm boundaries. I then examine how an economic crisis may impact these variables and change efficient firm boundaries. The various theories of the firm have difficulties explaining how firms efficiently adapt their boundaries to such prominent characteristics of economic crisis as declining demand and increased costs of external finance. However, all these theories stress uncertainty as an antecedent of firm organization, and as uncertainty is also an important characteristic of an economic crisis I examine how uncertainty is allowed to play out in the various theories in order to identify what predictions we can derive from the theory regarding changes in efficient firm boundaries as consequence of changes in uncertainty. The analysis suggests that we need to be more precise in describing the nature of the uncertainty that is assumed in the various theories. Moreover, allowing for changes in levels of uncertainty requires that we take the processes of boundary changes into account in the theory of firm boundaries.
Real and Imagined Body Movement Primes Metaphor Comprehension
Authors: Wilson Nicole L. , Gibbs Raymond W. 
Published: December 2010

AbstractWe demonstrate in two experiments that real and imagined body movements appropriate to metaphorical phrases facilitate people's immediate comprehension of these phrases. Participants first learned to make different body movements given specific cues. In two reading time studies, people were faster to understand a metaphorical phrase, such as push the argument, when they had previously just made an appropriate body action (e.g., a push movement) (Experiment 1), or imagined making a specific body movement (Experiment 2), than when they first made a mismatching body action (e.g., a chewing movement) or no movement. These findings support the idea that appropriate body action, or even imagined action, enhances people's embodied, metaphorical construal of abstract concepts that are referred to in metaphorical phrases.
Direct renin inhibition in addition to or as an alternative to angiotensin converting enzyme inhibition in patients with chronic systolic heart failure: rationale and design of the Aliskiren Trial to Minimize OutcomeS in Patients with HEart failuRE (ATMOSPHERE) study
Authors: Krum Henry , Massie Barry , Abraham William T. , Dickstein Kenneth , Kober Lars , McMurray John J.V. , Desai Ashkay , Gimpelewicz Claudio , Kandra Albert , Reimund Bernard , Rattunde Henning , Armbrecht Juergen ,   on behalf of the ATMOSPHERE Investigators
Published: December 2010

AimsThe renin–angiotensin–aldosterone system (RAAS) represents a key therapeutic target in heart failure (HF) management. However, conventional agents that block this system induce a reflex increase in plasma renin activity (PRA), which may lead to RAAS ‘escape'. Direct renin inhibitors (DRIs) have been developed that decrease PRA and thus may provide a greater RAAS blockade. Aliskiren is the first orally active DRI. Plasma levels of B‐type natriuretic peptide (BNP) have been observed to be reduced with aliskiren compared with placebo. The aim of the Aliskiren Trial of Minimizing OutcomeS for Patients with HEart failuRE (ATMOSPHERE) study is to evaluate the effect of both aliskiren and enalapril monotherapy and aliskiren/enalapril combination therapy on cardiovascular death and HF hospitalization in patients with chronic systolic HF, NYHA functional class II–IV symptoms, and elevated plasma levels of BNP.MethodsPatients tolerant to at least 10 mg or equivalent of enalapril will undergo an open‐label run‐in period where they receive enalapril then aliskiren. Approximately 7000 patients tolerating this run‐in period will then be randomized 1:1:1 to aliskiren monotherapy, enalapril monotherapy, or the combination. The primary endpoints of ATMOSPHERE are (i) whether the aliskiren/enalapril combination is superior to enalapril monotherapy in delaying time to first occurrence of cardiovascular death or HF hospitalization and (ii) whether aliskiren monotherapy is superior or at least non‐inferior to enalapril monotherapy on this endpoint.PerspectiveThe ATMOSPHERE study will definitively determine the role of a DRI strategy additional to or as an alternative to conventional RAAS blockade in patients with chronic systolic HF.
GAY SCIENCE AND (NO) LAUGHING MATTER: THE ETERNAL RETURNS OF MICHEL HOUELLEBECQ
Authors: Moore Gerald 
Published: December 2010

Abstract

Michel Houellebecq has repeatedly presented his literary work as something of a return to Schopenhauer. Yet this interpretation risks understating the complexity of Houellebecq's negotiations with Nietzsche — the self-proclaimed enemy of Schopenhauer — and the Nietzscheanism of
la génération 68
. In particular, it overlooks both his repetition of the Nietzschean themes of eternal return and Zarathustran laughter and the constitutive parody of this repetition, the effect of which is simultaneously to offer, withdraw, and suspend the withdrawal of the criticisms he articulates. The ambiguity plays out across
Les Particules élémentaires
(1998) and
La Possibilité d'une île
(2005), both of which can be read as staging a tension between two extreme, commodified versions of eternal return, namely the exhausted pseudo-transgression of popularized Zarathustra and a literal eternal return achieved through the science of cloning. These parodies of science and laughter contribute to Houellebecq's depiction of lifelessness rather than the joys of existence, but manage to preserve the prospect of affirming life in spite of nihilism. Filtered through an imminent critique of the post-68 reduction of philosophy to laughter, parody becomes a condition of Houellebecq's earnest reworking of the French Nietzschean legacy.
Combined immunohistochemistry for the differential diagnosis of cystic jaw lesions: its practical use in surgical pathology
Authors: Tsuneki Masayuki , Yamazaki Manabu , Cheng Jun , Maruyama Satoshi , Kobayashi Takanori , Saku Takashi 
Published: December 2010

Tsuneki M, Yamazaki M, Cheng J, Maruyama S, Kobayashi T & Saku T (2010) Histopathology57, 806–813 Combined immunohistochemistry for the differential diagnosis of cystic jaw lesions: its practical use in surgical pathology Aims:  Histopathological distinction of cystic jaw lesions, including odontogenic tumours, is challenging because their lining epithelia, which are basically stratified squamous epithelia, resemble each other, especially when they become hyperplastic from inflammatory reaction. The aim of this study was to seek practical measures to differentiate such lesions.Methods and results:  Nineteen surgical specimens from unicystic ameloblastomas (UAs), 17 from keratocystic odontogenic tumours (KCOTs), 13 from dentigerous cysts (DCs), 10 from lateral periodontal cysts (LPCs) and 20 from radicular cysts (RCs), all of which contained both typical flat and rete‐peg‐shaped lining epithelia, were examined for their immunohistochemical profiles. Among them, keratin (K) 10, K17, perlecan, proliferating cell nuclear antigen (PCNA) and UEA‐I lectin binding (UEA) were selected as useful immunohistochemical markers for their differential diagnosis. K10 was positive (+) in KCOT and DC. K17 was not present in RC. Perlecan was found in UA, KCOT and LPC. PCNA+ cells were found frequently in UA and KCOT. These localization patterns were constant even when linings were not flat.Conclusions:  Using a combination of six kinds of immunohistochemical pattern, it is now possible to discriminate reliably and objectively these five cystic jaw lesions in routine practice.