bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of multiarmed poly(3‐hexyl thiophene) star polymer with microgel core by GRIM and ATRP methods
Authors: Kim Hyun‐Ji , Lee Yun Jae , Hwang Seung Sang , Choi Dong Hoon , Yang Hoichang , Baek Kyung‐Youl
Published: July 2011

Regioregular poly(3‐hexyl thiophene) (rr‐P3HT)‐based star polymers were synthesized by a crosslinking reaction of the linear rr‐P3HT macroinitiator and ethylene glycol dimethacrylate (EGDMA) crosslinker through Ru‐based atom transfer radical polymerization (ATRP), where the rr‐P3HT macroinitiator was prepared by Grignard metathesis method (GRIM) followed by end functionalization of the ATRP initiator with chlorophenylacetate (CPA) to the rr‐P3HT. Relatively high molecular weight of the star polymers were obtained (Mp = 8,988,000 g/mol), which consisted of large numbers of the rr‐P3HT arm chains radiating from the EGDMA‐based microgel core. The yield of the star polymers were strongly affected by the added amount of the EGDMA crosslinker. The crystalline structure of the rr‐P3HT by intermolecular π‐π stacking interaction gradually decreased as the star polymer formed, which was confirmed by differential scanning calorimeter (DSC), atomic force microscopy (AFM), and electro‐optical analyses. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Electron paramagnetic resonance measurement of trapped radical concentrations in frontally polymerized and bulk‐polymerized multifunctional (meth)acrylates
Authors: Thoma Anna , Dahal Ashutosh , Regmi Aayush , Valencia Alecia , Viner Veronika , Cueto Rafael , Baker Blane , Bunton Patrick , Pojman John A.
Published: July 2011

For the first time, electron paramagnetic resonance spectroscopy was used to compare numbers and distributions of radicals produced in frontal free‐radical polymerization of multifunctional acrylates and methacrylates to those produced by bulk free‐radical polymerization. A comparison of radical concentrations was performed for individual polymers and selected copolymers of trimethylolpropane trimethacrylate (TMPTMA), 1,6‐hexanediol diacrylate, trimethylolpropane triacrylate, and pentaerythritol tetraacrylate (PETA). Frontally polymerized samples showed a large spike in intensity at the point of initiation. Within a few centimeters, the radical signal diminished to a steady state. The radical concentration remained almost constant over 3 months under helium in flame‐sealed tubes. The types of radicals were similar to those in bulk polymerization. For both TMPTMA and PETA, frontally polymerized samples had significantly higher numbers of radicals than did the bulk‐prepared samples, achieving concentrations as high as 8.7 × 10−3 mol/kg in the frontally prepared samples of TMPTMA. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
High modulus ratio shape‐memory polymers achieved by combining hydrogen bonding with controlled crosslinking
Authors: Pan Yi , Liu Tuo , Li Jing , Zheng Zhaohui , Ding Xiaobin , Peng Yuxing
Published: July 2011

A new type of poly(methyl acrylate)‐co‐(acrylic acid) (PMA‐AA) networks obtained by combining hydrogen bonding with controlled crosslinking exhibit full and rapid shape‐memory recovery. The structure, thermal properties, dynamical mechanical properties and shape‐memory effects of these networks were presented. High modulus ratios were achieved for the series of PMA‐AA networks based on intense self‐complementary hydrogen bonding in poly(acrylic acid) (PAA) segments. This lead to excellent shape‐memory effects with strain‐recovery ratio above 99%. Meanwhile, faster recovery speed was achieved by the synergistic effect of hydrogen bonding and controlled crosslinking compared to the linear PMA‐AA copolymers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1241–1245, 2011
Integrated waveguide sensor utilizing organic photodiodes
Authors: Lamprecht Bernhard , Kraker Elke , Sagmeister Martin , Köstler Stefan , Galler Nicole , Ditlbacher Harald , Ungerböck Birgit , Abel Tobias , Mayr Torsten
Published: July 2011

We present a novel optical sensor platform, combining monolithically integrated ring‐like sensor waveguides together with ring‐shaped thin‐film organic photodiodes (OPDs) on one substrate. The OPDs serve as integrated light detectors, simplifying the detection system by minimizing the number of required optical components. The waveguide structures, including a means of coupling light in and out of the waveguides, serve as sensing elements. The functionality of the concept is demonstrated by an integrated carbon dioxide sensor, utilizing absorbance as sensing principle. The integrated optical sensor platform is suitable for the parallel detection of multiple parameters in a single sensor chip using sensor arrays. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Conditional symmetric instability in sting‐jet storms
Authors: Gray S. L. , Martínez‐Alvarado O. , Baker L. H. , Clark P. A.
Published: July 2011

Sting jets are transient mesoscale jets of air that descend from the tip of the cloud head towards the top of the boundary layer in severe extratropical cyclones and can lead to damaging surface wind gusts. This recently identified jet is distinct from the well‐documented jets associated with the cold and warm conveyor belts. One mechanism proposed for their development is the release of conditional symmetric instability (CSI). Here the spatial distribution and temporal evolution of several CSI diagnostics in four severe storms are analysed. A sting jet has been identified in three of these storms; for comparison, we also analysed one storm that did not have a sting jet, even though it had many of the apparent features of sting‐jet storms. The sting‐jet storms are distinct from the non‐sting‐jet storms by having much greater and more extensive conditional instability (CI) and CSI. CSI is released by ascending air parcels in the cloud head in two of the sting‐jet storms and by descending air parcels in the other sting‐jet storm. By contrast, only weak CI to ascending air parcels is present at the cloud‐head tip in the non‐sting‐jet storm. CSI released by descending air parcels, as diagnosed by decaying downdraught slantwise convective available potential energy (DSCAPE), is collocated with the sting jets in all three sting‐jet storms and has a localised maximum in two of them. Consistent evolutions of saturated moist potential vorticity are found. We conclude that CSI release has a role in the generation of the sting jet, that the sting jet may be driven by the release of instability to both ascending and descending parcels, and that DSCAPE could be used as a discriminating diagnostic for the sting jet based on these four case‐studies. Copyright © 2011 Royal Meteorological Society and British Crown Copyright, the Met Office
A maximum entropy approach to the problem of parametrization
Authors: Verkley W. T. M.
Published: July 2011

It is shown that the principle of maximum entropy, as formulated by Jaynes, can be applied to parametrize the effect of unresolved variables on resolved variables in a dynamical system proposed by Lorenz. The starting point is the assumption that the unresolved variables are in a state of statistical equilibrium on the time‐scale of the resolved variables. The probability density function that describes the statistics of the unresolved variables is then determined by requiring that its information entropy is maximal under the constraint that the average time rate of change of the unresolved variables' energy is zero. By using this probability density function to determine the average effect of the unresolved variables on the resolved variables, a linear damping of the resolved variables is found. After incorporating the linear damping in the equations of the resolved system, the principle of maximum entropy is applied a second time to shed light on the statistics of the resolved system. The consequences are studied of using a priori probability density functions that go beyond Laplace's principle of indifference. Copyright © 2011 Royal Meteorological Society
Monitoring binary outcomes using risk‐adjusted charts: a comparative study
Authors: Gombay Edit , Hussein Abdulkadir A. , Steiner Stefan H.
Published: July 2011

Monitoring binary outcomes when evaluating health care performance has recently become common. Classical statistical methodologies such as cumulative sum (CUSUM) charts have been refined and used for this purpose. For instance, the risk‐adjusted CUSUM chart (RA‐CUSUM) for monitoring binary outcomes was proposed for monitoring 30‐day mortality following cardiac surgery. The RA‐CUSUM inherits optimality properties of the original CUSUM charts in the sense of signaling early when there is change. However, although the RA‐CUSUM is a powerful monitoring tool, it will always eventually signal a change with probability 1 even when there is no real change. In other words, the probability of a type I error for the RA‐CUSUM is 1. It also turns out that, because of the skewed distribution of the run lengths of the RA‐CUSUM, the median is often well below the mean, and as a consequence more than half of all its false alarms occur before the designed average run length. In addition, when the change to be detected occurs at a later time in the series of observations being monitored, the rate of false alarms increases, and the RA‐CUSUM may not be appropriate. Therefore, if the price of false alarms is high, it is preferable to use methods that control the rate of false alarms. In this paper, we propose alternative sequential curtailed and risk‐adjusted charts that control the type I error rate in the context of monitoring 30‐day mortality following cardiac surgery. We explore the merits of each of these methodologies in terms of average run lengths as well as in terms of type I error probabilities, and we compare them to the RA‐CUSUM chart. We illustrate the methodologies by using data on monitoring performance of seven surgeons from a medical center. Copyright © 2011 John Wiley & Sons, Ltd.
Semiparametric transformation models for joint analysis of multivariate recurrent and terminal events
Authors: Zhu Liang , Sun Jianguo , Srivastava Deo Kumar , Tong Xingwei , Leisenring Wendy , Zhang Hui , Robison Leslie L.
Published: July 2011

Recurrent event data occur in many clinical and observational studies, and in these situations, there may exist a terminal event such as death that is related to the recurrent event of interest. In addition, sometimes more than one type of recurrent events may occur, that is, one may encounter multivariate recurrent event data with some dependent terminal event. For the analysis of such data, one must take into account the dependence among different types of recurrent events and that between the recurrent events and the terminal event. In this paper, we extend a method for univariate recurrent and terminal events and propose a joint modeling approach for regression analysis of the data and establish the finite and asymptotic properties of the resulting estimates of unknown parameters. The method is applied to a set of bivariate recurrent event data arising from a long‐term follow‐up study of childhood cancer survivors. Copyright © 2011 John Wiley & Sons, Ltd.
Extended mixture factor analysis model with covariates for mixed binary and continuous responses
Authors: An Xinming , Bentler Peter M.
Published: July 2011

Finite mixture factor analysis provides a parsimonious model to explore latent group structures of high‐dimensional data. In this modeling framework, we can explore latent structures for continuous responses. However, dichotomous items are often used to define latent domains in practice. This paper proposes an extended finite mixture factor analysis model with covariates to model mixed continuous and binary responses. We use a Monte Carlo expectation–maximization (MCEM) algorithm to estimate the model. In the E step, closed‐form solutions are not available for the conditional expectation of complete data log likelihood, so it is approximated by sample means, which are in turn generated by the Gibbs sampler from the joint conditional distribution of latent variables. To monitor the convergence of the MCEM algorithm, we use bridge sampling to calculate the log likelihood ratio of two successive iterations. We adopt a diagnostic plot of the log likelihood ratio against iterations for monitoring the convergence of the MCEM algorithm. We compare different models based on BIC, in which we approximate the observed data log likelihood by using a Monte Carlo method. We investigate the computational properties of the MCEM algorithm by simulation studies. We use a real data example to illustrate the practical usefulness of the model. Finally, we discuss limitations and possible extensions. Copyright © 2011 John Wiley & Sons, Ltd.
Assessing covariate imbalance in meta‐analysis studies
Authors: Aiello Fabio , Attanasio Massimo , Tinè Fabio
Published: July 2011

The main goal of meta‐analysis is to combine data across studies or data sets to obtain summary estimates. In this paper, the novelty is to propose a statistical tool to assess a possible covariate imbalance in baseline variables to investigate similarity of trials. We conducted the detection of the covariate imbalance, first, through some graphical comparison of the empirical cumulative distribution functions or ECDFs, which are built by putting together arms or trials according to some risk factor, and second, through some non‐parametric tests such as the Kolmogorov–Smirnov and the Anderson–Darling tests. To overcome the huge presence of ties, we conducted the statistical tests on perturbed versions of the original data sets. The applications concern two real meta‐analyses of RCTs: the first one, on interferon‐alpha treatment of chronic hepatitis C, with 107 studies involved, and the second one, on cholesterol‐lowering treatment with statins, with 14 studies involved.

The applications allow for analysis of both when risk factors reflecting demographic or clinical differences in experimental and control arms are balanced or not and when there are structural differences between the levels of some study variables, in order to proceed eventually with the pooling of the studies. We developed our suggestion, which is a quantitative way to assess combinability in meta‐analysis, only with respect to RCTs, but it could be applied to a minor extent to non‐RCTs. Copyright © 2011 John Wiley & Sons, Ltd.
A quasiF‐test for functional linear models with functional covariates and its application to longitudinal data
Authors: Xu Hongquan , Shen Qing , Yang Xiaowei , Shoptaw Steven
Published: July 2011

Functional linear models are useful in analyzing data from designed experiments and observational studies with functional responses, as well as longitudinal data with a large number of repeated measures on each subject. We propose a quasiF‐test for functional linear models with functional covariates and outcomes. We develop a numerical procedure and an efficient approximation for computingp‐values, and present a simple way to test individual predictors. For illustration, we apply the proposed procedure to a longitudinal depression data set with repeatedly measured methamphetamine use as a predictor. We conduct a simulation study to assess the size and the power of the test. Copyright © 2011 John Wiley & Sons, Ltd.
Modeling continuous diagnostic test data using approximate Dirichlet process distributions
Authors: Ladouceur Martin , Rahme Elham , Bélisle Patrick , Scott Allison N. , Schwartzman Kevin , Joseph Lawrence
Published: July 2011

There is now a large literature on the analysis of diagnostic test data. In the absence of a gold standard test, latent class analysis is most often used to estimate the prevalence of the condition of interest and the properties of the diagnostic tests. When test results are measured on a continuous scale, both parametric and nonparametric models have been proposed. Parametric methods such as the commonly used bi‐normal model may not fit the data well; nonparametric methods developed to date have been relatively complex to apply in practice, and their properties have not been carefully evaluated in the diagnostic testing context. In this paper, we propose a simple yet flexible Bayesian nonparametric model which approximates a Dirichlet process for continuous data. We compare results from the nonparametric model with those from the bi‐normal model via simulations, investigating both how much is lost in using a nonparametric model when the bi‐normal model is correct and how much can be gained in using a nonparametric model when normality does not hold. We also carefully investigate the trade‐offs that occur between flexibility and identifiability of the model as different Dirichlet process prior distributions are used. Motivated by an application to tuberculosis clustering, we extend our nonparametric model to accommodate two additional dichotomous tests and proceed to analyze these data using both the continuous test alone as well as all three tests together. Copyright © 2011 John Wiley & Sons, Ltd.
A dependency‐aware ontology‐based approach for deploying service level agreement monitoring services in Cloud
Authors: Dastjerdi Amir Vahid , Tabatabaei Sayed Gholam Hassan , Buyya Rajkumar
Published: July 2011

Cloud computing offers virtualized computing elements on demand in a pay‐as‐you‐go manner. The major motivations to adopt Cloud services include no upfront investment on infrastructure and transferring responsibility of maintenance, backups, and license management to Cloud Providers. However, one of the key challenges that holds businesses from adopting Cloud computing services is that, by migrating to Cloud, they move some of their information and services out of their direct control. Their main concern is how well the Cloud providers keep their information (security) and deliver their services (performance). To cope with this challenge, several service level agreement management systems have been proposed. However, monitoring service deployment as a major responsibility of those systems have not been deeply investigated yet. Therefore, this paper shows how monitoring services have to be described, deployed (discovered and ranked), and then how they have to be executed to enforce accurate penalties by eliminating service level agreement failure cascading effects on violation detection. Copyright © 2011 John Wiley & Sons, Ltd.
Adaptive routing algorithm for network load balancing
Authors: Une Hiroyuki , Qian Fei , Hirata Hironori
Published: July 2011

This paper introduces a routing algorithm which distributes the network traffic for each feasible route based on the reinforcement learning scheme. The aim of this algorithm is to reduce the transfer delay caused by congestion of the network. Most routing algorithms based on the reinforcement learning scheme could not avoid forwarding traffic toward the source of data packets. This property creates transfer loops and a lot of packet loss. In particular, the transfer loop may cause change in the order of packets, and also retransmit on the TCP connection. Thus, we employ a method that estimates the lower boundary of the probability for valid route to the destination, and this lower boundary can be used to reject the routes which cause the transfer loop. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Relationship between intracellular Ca2+ and ROS during fluoride‐induced injury in SH‐SY5Y cells
Authors: Xu Zhixia , Xu Bayi , Xia Tao , He Weihong , Gao Ping , Guo Lijuan , Wang Zhenglun , Niu Qiang , Wang Aiguo
Published: July 2011

The mechanisms underlying the neurotoxicology of endemic fluorosis still remain obscure. To explore lactate dehydrogenase (LDH) leakage, intracellular Ca2+ concentration ([Ca2+]i) and reactive oxygen species (ROS) production induced by fluoride, human neuroblastoma (SH‐SY5Y) cells were incubated with sodium fluoride (NaF, 20, 40, 80 mg/L) for 24 h, with 40 mg/L NaF for 3, 6, 12, 18, 24 h, and N‐acetyl‐L‐cysteine (NAC), ethyleneglycol‐bis‐(β‐aminoethyl ether)‐N,N,N′,N′‐tetraacetic acid (EGTA), 1,2‐bis(O‐aminophenoxy)ethane‐N,N,N′,N′‐tetraacetic acid tetra(acetoxymethyl) ester (BAPTA‐AM) alone or combined with fluoride (40 mg/L) respectively for 12 h in vitro. The results showed that the LDH levels in the 40 and 80 mg/L fluoride‐treated groups were significantly higher than that of the control group (in the test level of 0.05, the difference were statistical significance). [Ca2+]i and ROS reached a peak at 3 h and 12 h respectively after exposure to 40 mg/L fluoride. Fluoride coincubated with NAC (antioxidant) dramatically decreased ROS and LDH levels compared with the fluoride only group (in the test level of 0.05, the difference were statistical significance). However, fluoride‐induced increase in [Ca2+]i was not affected by NAC. BAPTA‐AM (intracellular calcium chelator) markedly lowered fluoride‐induced increase of [Ca2+]i, ROS and LDH levels while EGTA (extracellular calcium chelator) have no effects on them. These results indicate that fluoride‐related Ca2+ release from the site of intracellular calcium storage causes the elevation of ROS contributing to the cytotoxicity in SH‐SY5Y cells. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2013.
Evaluation of DNA damage and cytotoxicity induced by three commonly used organophosphate pesticides individually and in mixture, in rat tissues
Authors: Ojha Anupama , Yaduvanshi Santosh Kumar , Pant Satish Chnadra , Lomash Vinay , Srivastava Nalini
Published: July 2011

Organophosphate pesticides are among the most widely used synthetic chemicals for controlling a wide variety of pests. Chlorpyrifos (CPF), methyl parathion (MPT), and malathion (MLT) are among the most extensively used organophosphate (OP) pesticides. The main target of action of OP compounds is the central and peripheral nervous system, although it has also been postulated that these compounds in both acute and chronic intoxication, disturb the redox processes and thus induce oxidative stress. The excessive generation of reactive oxygen species (ROS) causes damage to all vital macromolecules including lipids, proteins, and DNA. This study was aimed to investigate the genotoxicity and cytotoxicity of CPF, MPT, and MLT when given singly or in combination. The DNA damage was measured by alkaline single‐cell gel electrophoresis or comet assay and expressed as DNA damage index. The results showed that both acute and chronic exposure with CPF, MPT, and MLT, caused significantly marked DNA damage in rat tissues namely, liver, brain, kidney, and spleen, when measured 24 hour posttreatment. It was also observed that MPT caused highest level of DNA damage and brain was maximally affected by these OP compounds. When these pesticides were given in mixture, the damage was not the sum of damage caused by individual pesticide, confirming that these pesticides do not potentiate the toxicity of each other. When the DNA damage was measured 48 and 72 hour posttreatment, the damage was partially repaired. Pesticide exposure also caused histopathological changes in rat tissues. © 2011 Wiley Periodicals, Inc. Environ Toxicol 28: 543–552, 2013.
Evaluation of factors associated with cadmium exposure and kidney function in the general population
Authors: Huang Mingai , Choi Seong‐Jin , Kim Dong‐Won , Kim Na‐Young , Bae Hye‐Sun , Yu Seung‐Do , Kim Dae‐Seon , Kim Heon , Choi Byung‐Sun , Yu Il‐Je , Park Jung‐Duck
Published: July 2011

Cadmium (Cd) is a nonessential toxic metal which is widely distributed in the environment. The general population is exposed to low levels of Cd and the kidney is the organ most sensitive to Cd toxicity. This study was performed to simultaneously evaluate Cd exposure, kidney function, and oxidative stress biomarkers in the general population. A total of 643 adults were interviewed to document demographic characteristics, lifestyles, past‐medical history, and diet during the last 24 h. We estimated daily Cd intake based on the diet of study subjects who had not been exposed to Cd occupationally. Whole blood and urine samples were collected and analyzed to determine Cd concentrations and kidney function indices (β2‐microglobulin [β2‐MG], N‐acetyl‐β‐D‐glucosaminidase [NAG], metallothionein [MT]). The oxidative stress index (malondialdehyde [MDA]) was determined from the urine. The daily Cd intake from diet was established as 7.07 μg/day. The mean concentration of Cd measured in the blood was 1.22 μg/L and urine was 0.95 μg/g creatinine. The concentrations of Cd in blood and urine were higher in females than in males. The blood levels of Cd were affected by sex, age, and smoking, and urine Cd was influenced by sex, age, and blood Cd. The urine Cd was positively correlated with MT, NAG activity, and MDA in females, but with NAG only in males. The blood Cd was associated with MT in males. Increased NAG activity was observed when Cd in urine reached 1.0 μg Cd/g creatinine and was also affected by age, hypertension, and diabetes mellitus. Urinary MT only responded to Cd in urine or blood. In summary, exposure to Cd in the general population was influenced by various factors including sex, age, and smoking habits. Such exposure might eventually cause tubular damage in the kidneys through the oxidative stress mechanism, and females might be more susceptible than males to Cd exposure under the environment. © 2011 Wiley Periodicals, Inc. Environ Toxicol 28: 563–570, 2013.
Exposed versus buried wires for fixation of lateral humeral condyle fractures in children: A comparison of safety and efficacy
Authors: Chan Lester Wai Mon , Siow Hua Ming
Published: July 2011

Introduction

Displaced fractures of the lateral condyle of the humerus are usually treated with open reduction and fixation with smooth Kirschner wires. These may be passed through the skin and left exposed or buried subcutaneously. Exposed wires may be removed in the outpatient clinic, whereas buried wires require a formal procedure under anaesthesia. This advantage may be offset if there is a higher rate of complications with exposed wires. The aim of this study was to compare the safety and efficacy of exposed and buried wires.

Study design

Retrospective cohort.

Methods and materials

Children with lateral condyle fractures of the humerus who had undergone surgery were identified from our departmental database. Case records and X-rays of 75 patients were reviewed.

Results

Forty-two patients had buried wires and 33 had exposed wires. There were no serious complications in either group. In the exposed wires group, 1 patient had a superficial wound infection that was treated effectively with 1 week of oral antibiotics, while 2 patients had hypergranulation of pin tracts treated with topical silver nitrate. None of the patients showed loss of reduction, deep infection, or any other complications requiring additional procedures.

Discussion/conclusions

There was no statistically significant difference in the rate of complications between the buried and exposed groups. We conclude that open reduction and exposed wiring is a safe and effective option for lateral condyle fractures, and recommend a period of 4 weeks of K-wire fixation followed by 2 weeks of backslab immobilisation as adequate for union with minimal risk of infection.
Gratitude and suicidal ideation and suicide attempts among Chinese Adolescents: Direct, mediated, and moderated effects
Authors: Li Dongping , Zhang Wei , Li Xian , Li Nini , Ye Baojuan
Published: July 2011

In a sample of 1252 Chinese adolescents (mean age = 15.00 years), this study examined the direct relations between gratitude and adolescents’ suicidal ideation and suicide attempts. This study also examined indirect relations between gratitude and suicidal ideation and suicide attempts via two self‐system beliefs—coping efficacy and self‐esteem. Finally, this study examined the extent to which stressful life events moderated the direct and indirect relations between gratitude and suicidal ideation and suicide attempts. The odds of suicidal ideation and suicide attempts were lower among adolescents who scored higher on gratitude, after controlling for demographic variables. Self‐esteem mediated the relations between gratitude and suicidal ideation and suicide attempts, while the mediating role of coping efficacy was not significant. Moreover, stressful life events moderated the mediated path through self‐esteem. This indirect effect was stronger for adolescents low on stressful life events than that for those high on stressful life events. This study discusses the theoretical and practical implications of these findings.
Trajectories of global self‐esteem development during adolescence
Authors: Birkeland Marianne Skogbrott , Melkevik Ole , Holsen Ingrid , Wold Bente
Published: July 2011

Based on data from a 17‐year longitudinal study of 1083 adolescents, from the ages of 13 to 30 years, the average development of self‐reported global self‐esteem was found to be high and stable during adolescence. However, there is considerable inter‐individual variance in baseline and development of global self‐esteem. This study used latent growth mixture modelling to characterize three trajectory classes of global self esteem between ages 14 and 23 years: consistently high, chronically low, and U‐shaped.

The respondents in three classes showed statistically significant different levels of life satisfaction, depressive mood, somatic complaints and insomnia at age 30. Attempts to predict trajectories from age 13 were only partially successful, with body image, relations with parents and frequency of physical activity as the significant predictors.
Ricci flow of conformally compact metrics
Authors: Bahuaud Eric
Published: July 2011

In this paper we prove that given a smoothly conformally compact asymptotically hyperbolic metric there is a short-time solution to the Ricci flow that remains smoothly conformally compact and asymptotically hyperbolic. We adapt recent results of Schnürer, Schulze and Simon to prove a stability result for conformally compact Einstein metrics sufficiently close to the hyperbolic metric.

Lʼobjectif de cet article est de démontrer lʼexistence dʼune solution en temps court du flot de Ricci dans la classe de métriques régulières, conformément compactes et asymptotiquement hyperboliques. Nous appliquons ensuite les résultats de Schnürer, Schulze et Simon pour prouver la stabilité des métriques dʼEinstein conformément compactes suffisamment proches de la métrique hyperbolique.
Reaction–diffusion front speed enhancement by flows
Authors: Zlatoš Andrej
Published: July 2011

We study flow-induced enhancement of the speed of pulsating traveling fronts for reaction–diffusion equations, and quenching of reaction by fluid flows. We prove, for periodic flows in two dimensions and any combustion-type reaction, that the front speed is proportional to the square root of the (homogenized) effective diffusivity of the flow. We show that this result does not hold in three and more dimensions. We also prove conjectures from Audoly, Berestycki and Pomeau (2000) [1], Berestycki (2003) [3], Fannjiang, Kiselev and Ryzhik (2006) [11] for cellular flows, concerning the rate of speed-up of fronts and the minimal flow amplitude necessary to quench solutions with initial data of a fixed (large) size.
Risk factors for very preterm delivery and delivery of very‐small‐for‐gestational‐age infants among HIV‐exposed and HIV‐unexposed infants in Botswana
Authors: Parekh Natasha , Ribaudo Heather , Souda Sajini , Chen Jennifer , Mmalane Mompati , Powis Kathleen , Essex Max , Makhema Joseph , Shapiro Roger L.
Published: July 2011

Objective

To evaluate risk factors for very preterm delivery (VPTD) and very‐small‐for‐gestational‐age (VSGA) births in a country with a high HIV prevalence.

Methods

Obstetric records at 6 hospitals across Botswana were reviewed at delivery; VPTD was defined as birth before 32 weeks of pregnancy and VSGA as birth weight below the 3rd percentile for Botswana‐specific norms.

Results

Of 16 219 live births born after 26 weeks of pregnancy, 701 (4.3%) were delivered very preterm and 607 (3.7%) were VSGA; 4347 (28.4%) were documented as HIV‐exposed. In a multivariable analysis, HIV infection and hypertension during pregnancy were associated with a VPTD (adjusted odds ratio [AOR]: HIV 1.65, hypertension 1.75) and a VSGA birth (AOR: HIV infection 1.90, hypertension 3.44). Among HIV‐infected women, the continuation of highly active antiretroviral therapy (HAART) from before conception was associated with a VSGA birth (AOR 1.75) but not with a VPTD (AOR 0.78). In a secondary analysis, HAART continuation was associated with hypertension during pregnancy (AOR 1.34).

Conclusion

Hypertension and HIV infection were risk factors for a VPTD and a VSGA birth. Continuation of HAART from before conception was associated with a VSGA birth but not with a VPTD.
Sleep quality based on the use of different sanitary pads during menstruation
Authors: Hachul Helena , Andersen Monica L. , Tufik Sergio
Published: July 2011

Objective

To evaluate sleep quality among women using 2 different types of sanitary pad.

Methods

Seventeen women (18–40 years) with menstrual cycles of 28–30 days and self‐reported moderate‐to‐intense menstrual flow were enrolled in a crossover study from March to August 2009 in Sao Paulo, Brazil. Sleep assessments were made by polysomnography and by means of validated questionnaires. The first evaluation of sleep (control condition) was performed during the follicular phase (7–10th day of cycle). There were subsequent evaluations during the 2nd and 3rd day of the menstrual period, and a different type of absorbent pad (A or B) was used on each day. The participants were randomly assigned to an order of pad use (AB or BA).

Results

The use of absorbent pad A or B did not affect the parameters of sleep or the quality of sleep. The results obtained with use of either absorbent pad did not differ significantly from the control condition and were within the normal limits.

Conclusion

There was no significant difference in sleep quality between the follicular phase and the menstrual period; in addition, the use of different absorbent pads over consecutive nights during the same menstrual cycle was not associated with changes in sleep.
Oesophageal disease in 33 cats
Authors: Frowde Polly E. , Battersby Ian A. , Whitley Nathaniel T. , Elwood Clive M.
Published: July 2011

A retrospective study was performed to investigate the frequency of identification and characteristics of oesophageal disease in cats, including assessment of the utility of diagnostic techniques and clinical outcome. Thirty-three cats met the inclusion criteria, giving an in-clinic frequency of 33/2894 (approximately 1%) of feline referral cases. Vomiting and/or regurgitation were the most common presenting signs described, although a number of cats (6/33) showed neither. Useful diagnostic modalities included plain radiography, fluoroscopy, barium radiography and endoscopy. A wide range of diseases was reported including congenital disease, oesophagitis, foreign body obstruction, neoplasia, extraluminal compression and hypomotility disorder. Five of six cats with acquired oesophageal strictures had recently received doxycycline per os.
Arbeitsmedizin – Quo vadis?
Authors: Hofmann Friedrich , Reschauer Georg , Stößel Ulrich
Published: July 2011

Einleitung

Der Beitrag versucht, eine kritische Standortbestimmung der akademischen Arbeits- und praktischen Betriebsmedizin in Deutschland zu geben. Der zu begrüßenden paradigmatischen Öffnung des Faches stehen aber erhebliche Entwicklungshindernisse entgegen.
Sozialkapitalbasierte Public Health-Strategie für die Arbeitswelt
Authors: Badura Bernhard
Published: July 2011

Einleitung

Der Sozialkapitalansatz erfreut sich einer großen Beliebtheit in unterschiedlichen wissenschaftlichen Disziplinen. Elinor Ostrom gewann den Nobelpreis für ihre Arbeit zum Nutzen des Sozialkapitals.
The effects of costly exploration on optimal investment timing
Authors: Nishihara Michi , Shibata Takashi
Published: July 2011

This paper investigates a principal–agent model in which an owner (principal) optimizes a contract with a manager (agent) who has been delegated to undertake an investment project. In the model, we explore the effects of costly exploration by which the manager learns the real value of development cost. We show that high exploration cost can lead to a pooling policy not contingent on project type. Further, and more notably, we show that, in the presence of asymmetric information, higher exploration cost leads to wealth transfer from owner to manager and can ultimately improve social welfare.
Comparison of nasal cytology and symptom scores in patients with seasonal allergic rhinitis, before and after treatment
Authors: Özgür A , Arslanoğlu S , Etıt D , Demıray U , Önal H K
Published: July 2011

Objective:

To evaluate symptom scores and nasal smear cytology findings in seasonal allergic rhinitis patients, before and after treatment.

Methods:

Twenty-nine consecutive adult patients with seasonal allergic rhinitis were evaluated prospectively. They received mometasone furoate nasal spray and cetirizine for 21 days. Nasal and ocular symptom scores were recorded before and after treatment. Nasal cytology was also assessed as a means of determining treatment.

Results:

The combined use of an intranasal corticosteroid and an oral antihistamine caused a significant improvement in nasal and ocular symptom scores. Cytological evaluation revealed significant reduction in nasal eosinophil, neutrophil and goblet cell counts after three weeks' treatment.

Conclusion:

Symptom scoring systems are widely used for the evaluation of drug efficacy in allergic rhinitis treatment. When investigating the disease and evaluating treatment efficacy, objective as well as subjective methods are needed. Nasal cytological assessment is a simple, objective method which provides valuable information about the nasal mucosa.
Prevalence of haemorrhagic fever with renal syndrome in mainland China: analysis of National Surveillance Data, 2004–2009
Authors: LIU X. , JIANG B. , BI P. , YANG W. , LIU Q.
Published: July 2011

The monthly and annual incidence of haemorrhagic fever with renal syndrome (HFRS) in China for 2004–2009 was analysed in conjunction with associated geographical and demographic data. We applied the seasonal autoregressive integrated moving average (SARIMA) model to fit and forecast monthly HFRS incidence in China. HFRS was endemic in most regions of China except Hainan Province. There was a high risk of infection for male farmers aged 30–50 years. The fitted SARIMA(0,1,1)(0,1,1)12 model had a root-mean-square-error criterion of 0·0133 that indicated accurate forecasts were possible. These findings have practical applications for more effective HFRS control and prevention. The conducted SARIMA model may have applications as a decision support tool in HFRS control and risk-management planning programmes.
Selection of Rattus norvegicus oocytes for in vitro maturation by brilliant cresyl blue staining
Authors: Alcoba Diego Duarte , da Rosa Braga Bianca Letícia , Sandi-Monroy Nathallie Louise , Proença Letícia Auler , Felix Lopes Rui Fernando , de Oliveira Alexandre Tavares Duarte
Published: July 2011

The objective of this work was to evaluate the rate of meiosis resumption and nuclear maturation of rat (Rattus norvegicus) oocytes selected for in vitro maturation (IVM) after staining of cumulus–oocyte complexes (COCs) with blue cresyl brilliant (BCB) using different protocols: exposure for 30, 60 or 90 min at 26 μM BCB (Experiment 1), and exposure for 60 min at 13, 20 or 26 μM BCB (Experiment 2). In Experiment 1, the selection of oocytes exposed to BCB for 60 min was found to be the most suitable, as meiosis resumption rates in the BCB+ group (n = 35/61; 57.37%) were the closest to the observed in the control (not exposed) group (n = 70/90; 77.77%) and statistically higher than the values observed for the BCB− group (n = 3/41; 7.32%). Additionally, the more effective evaluation of diagnostic tests (sensitivity and negative predictive value 100%) was observed in COCs exposed for 60 min. In Experiment 2, the 13 μM BCB+ group presented rates of meiosis resumption (n = 57/72; 72.22%) similar to the control group (n = 87/105; 82.86%) and higher than other concentration groups. However, this results of the analysis between BCB− oocytes was also higher in the 13 μM BCB group (n = 28/91; 30.78%) when compared with BCB− COCs exposed to 20 μM (n = 3/62; 4.84%) or 26 μM (n = 3/61; 4.92%) BCB. The nuclear maturation rate in the 13 μM BCB group was similar between BCB+ or BCB− oocytes. The 20 μM BCB group had a lower rate of nuclear maturation of BCB− oocytes than other groups. Thus, our best results in the selection of Rattus norvegicus oocytes by staining with BCB were obtained using the concentration of 13 μM and 20 μM, and an incubation period of 60 min.
Comparative testing of four ionospheric models driven with GPS measurements
Authors: Feltens J. , Angling M. , Jackson‐Booth N. , Jakowski N. , Hoque M. , Hernández‐Pajares M. , Aragón‐Àngel A. , Orús R. , Zandbergen R.
Published: July 2011

In the context of the European Space Agency/European Space Operations Centre funded Study “GNSS Contribution to Next Generation Global Ionospheric Monitoring,” four ionospheric models based on GNSS data (the Electron Density Assimilative Model, EDAM; the Ionosphere Monitoring Facility, IONMON v2; the Tomographic Ionosphere model, TOMION; and the Neustrelitz TEC Models, NTCM) have been run using a controlled set of input data. Each model output has been tested against differential slant TEC (dSTEC) truth data for high (May 2002) and low (December 2006) sunspot periods. Three of the models (EDAM, TOMION, and NTCM) produce dSTEC standard deviation results that are broadly consistent with each other and with standard deviation spreads of ∼1 TECu for December 2006 and ∼1.5 TECu for May 2002. The lowest reported standard deviation across all models and all stations was 0.99 TECu (EDAM, TLSE station for December 2006 night). However, the model with the best overall dSTEC performance was TOMION which has the lowest standard deviation in 28 out of 52 test cases (13 stations, two test periods, day and night). This is probably related to the interpolation techniques used in TOMION exploiting the spatial stationarity of vertical TEC error decorrelation.
Ice sheet–derived submarine groundwater discharge on Greenland's continental shelf
Authors: DeFoor Whitney , Person Mark , Larsen Hans Christian , Lizarralde Daniel , Cohen Denis , Dugan Brandon
Published: July 2011

Isotopically light (−1‰ to −8‰ ) and fresh pore fluids (300–520 mM Cl−) were found in continental shelf sediments up to 100 km offshore of southeastern (SE) Greenland, suggesting infiltration and mixing of ice sheet meltwater with seawater to depths of 260 m. These geochemical anomalies may be associated with ice sheet–derived submarine groundwater discharge (SMGD). We present a continental‐scale reconstruction of the late Pleistocene hydrogeology of SE Greenland using finite element analysis that incorporates ice sheet loading and solute and isotope transport. Results indicate that subglacial infiltration and SMGD are of the same order of magnitude and are highly dependent on the permeability of the subaerial basalt. Simulated infiltration and SMGD almost doubled during the Last Glacial Maximum, compared to ice‐free conditions. Much of the present‐day glacially induced groundwater discharge occurs on land. Subice infiltration on the continental shelf likely represents a mixture of seawater and meltwater during past glacial maximums. Simulated SMGD during the most recent interval of glacial retreat is about 4% of the total ice sheet melting. At present, the simulated rate of SMGD is about 11% of the estimated current melting rate.
Kinetic models of partially ionized complex plasmas in the low frequency regime
Authors: Tolias P. , Ratynskaia S. , de Angelis U.
Published: July 2011

The results from three kinetic models of complex plasmas taking into account collisions with neutrals are compared in the low-frequency regime: The “full” model which considers the absorption of plasma fluxes on dust particles and dust charge fluctuations, the “multi-component” model where both these effects are neglected, and the “standard” model which takes into account the dust charge perturbations but not the absorption of fluxes. We derive and numerically evaluate expressions of the low frequency responses of these models, also taking into account the modification of the capture cross-sections due to the effect of neutrals. The role of plasma sources and collisions with neutrals is assessed by computing the plasma permittivities and static permittivities for all the three models.
Urban Transportation Public–Private Partnerships: Drivers of Uneven Development?
Authors: Siemiatycki Matti
Published: July 2011

Around the world, public–private partnerships (PPPs) have been widely promoted as a model to expand the provision of critical urban transportation infrastructure. This paper examines the extent to which PPPs have actually been used to deliver urban transportation infrastructure, and whether this model of project delivery has redressed historically uneven patterns of global infrastructure investment. Through an analysis of over 950 transportation PPPs worldwide over the past quarter century, it is shown that only one third were projects built in urban areas. Of these urban projects, PPPs have been concentrated in the largest and wealthiest cities in a small number of countries, largely supported road projects rather than public transit, and been an unstable source of funding during periods of economic volatility. These uneven patterns of project development are explained by three interrelated factors: overlapping jurisdictions in urban governance, project risk profiles, and market interest. The paper concludes by reflecting on the theoretical and policy implications of these findings.
Does the National School Lunch Program Improve Children's Dietary Outcomes?
Authors: Campbell Benjamin L. , Nayga Rodolfo M. , Park John L. , Silva Andres
Published: July 2011

The National School Lunch Program's effect on children's diets has been extensively studied. Results have tended to be inconclusive regarding the effectiveness of the program. Utilizing more specific treatment groups, we find that participants in the National School Lunch Program do not consume a higher‐quality diet at lunch than children choosing not to participate, even though the program is offered—but rather consume a higher quantity of foods while consuming similar amounts at other meals. Furthermore, children attending schools not participating in the National School Lunch Program have dietary outcomes that are not significantly different from program participants.
CAM-CM: a signal deconvolution tool for in vivo dynamic contrast-enhanced imaging of complex tissues
Authors: Chen Li , Chan Tsung-Han , Choyke Peter L. , Hillman Elizabeth M. C. , Chi Chong−Yung , Bhujwalla Zaver M. , Wang Ge , Wang Sean S. , Szabo Zsolt , Wang Yue
Published: July 2011

Summary:  In vivo dynamic contrast-enhanced imaging tools provide non-invasive methods for analyzing various functional changes associated with disease initiation, progression and responses to therapy. The quantitative application of these tools has been hindered by its inability to accurately resolve and characterize targeted tissues due to spatially mixed tissue heterogeneity. Convex Analysis of Mixtures – Compartment Modeling (CAM-CM) signal deconvolution tool has been developed to automatically identify pure-volume pixels located at the corners of the clustered pixel time series scatter simplex and subsequently estimate tissue-specific pharmacokinetic parameters. CAM-CM can dissect complex tissues into regions with differential tracer kinetics at pixel-wise resolution and provide a systems biology tool for defining imaging signatures predictive of phenotypes.

Availability: The MATLAB source code can be downloaded at the authors′ website www.cbil.ece.vt.edu/software.htm

Contact:  yuewang@vt.edu

Supplementary information:  Supplementary data are available at Bioinformatics online.