bluuebunny/crossref_metadata_2025_split huggingface dataset:
Joint modeling of longitudinal data and informative dropout time in the presence of multiple changepoints
Authors: Ghosh Pulak , Ghosh Kaushik , Tiwari Ram C. 
Published: November 2010

AbstractIn longitudinal studies of patients with the human immunodeficiency virus (HIV), objectives of interest often include modeling of individual‐level trajectories of HIV ribonucleic acid (RNA) as a function of time. Such models can be used to predict the effects of different treatment regimens or to classify subjects into subgroups with similar trajectories. Empirical evidence, however, suggests that individual trajectories often possess multiple points of rapid change, which may vary from subject to subject. Additionally, some individuals may end up dropping out of the study and the tendency to drop out may be related to the level of the biomarker. Modeling of individual viral RNA profiles is challenging in the presence of these changes, and currently available methods do not address all the issues such as multiple changes, informative dropout, clustering, etc. in a single model.In this article, we propose a new joint model, where a multiple‐changepoint model is proposed for the longitudinal viral RNA response and a proportional hazards model for the time of dropout process. Dirichlet process (DP) priors are used to model the distribution of the individual random effects and error distribution. In addition to robustifying the model against possible misspecifications, the DP leads to a natural clustering of subjects with similar trajectories which can be of importance in itself. Sharing of information among subjects with similar trajectories also results in improved parameter estimation.A fully Bayesian approach for model fitting and prediction is implemented using MCMC procedures on the ACTG 398 clinical trial data. The proposed model is seen to give rise to improved estimates of individual trajectories when compared with a parametric approach. Copyright © 2010 John Wiley & Sons, Ltd.
Parametric mixture models to evaluate and summarize hazard ratios in the presence of competing risks with time‐dependent hazards and delayed entry
Authors: Lau Bryan , Cole Stephen R. , Gange Stephen J. 
Published: November 2010

AbstractIn the analysis of survival data, there are often competing events that preclude an event of interest from occurring. Regression analysis with competing risks is typically undertaken using a cause‐specific proportional hazards model. However, modern alternative methods exist for the analysis of the subdistribution hazard with a corresponding subdistribution proportional hazards model. In this paper, we introduce a flexible parametric mixture model as a unifying method to obtain estimates of the cause‐specific and subdistribution hazards and hazard‐ratio functions. We describe how these estimates can be summarized over time to give a single number comparable to the hazard ratio that is obtained from a corresponding cause‐specific or subdistribution proportional hazards model. An application to the Women's Interagency HIV Study is provided to investigate injection drug use and the time to either the initiation of effective antiretroviral therapy, or clinical disease progression as a competing event. Copyright © 2010 John Wiley & Sons, Ltd.
A method to estimate treatment efficacy among latent subgroups of a randomized clinical trial
Authors: Altstein Lily L. , Li Gang , Elashoff Robert M. 
Published: November 2010

AbstractSubgroup analysis arises in clinical trials research when we wish to estimate a treatment effect on a specific subgroup of the population distinguished by baseline characteristics. Many trial designs induce latent subgroups such that subgroup membership is observable in one arm of the trial and unidentified in the other. This occurs, for example, in oncology trials when a biopsy or dissection is performed only on subjects randomized to active treatment. We discuss a general framework to estimate a biological treatment effect on the latent subgroup of interest when the survival outcome is right‐censored and can be appropriately modelled as a parametric function of covariate effects. Our framework builds on the application of instrumental variables methods to all‐or‐none treatment noncompliance. We derive a computational method to estimate model parameters via the EM algorithm and provide guidance on its implementation in standard software packages. The research is illustrated through an analysis of a seminal melanoma trial that proposed a new standard of care for the disease and involved a biopsy that is available only on patients in the treatment arm. Copyright © 2010 John Wiley & Sons, Ltd.
The effects of socioeconomic globalization on health and aging in highlanders compared to lowlanders in Yunnan, China, and Kochi, Japan
Authors: Okumiya Kiyohito , Ishine Masayuki , Kasahara Yoriko , Wada Taizo , Sakamoto Ryota , Kosaka Yasuyuki , Ishimoto Yasuko , Hirosaki Mayumi , Kimura Yumi , Fujisawa Michiko , Otsuka Kuniaki , Tan Xiaoxia , Zhang Hai , Zhao Haijuan , Er Wu Ni , Yin Shaoting , Matsubayashi Kozo 
Published: November 2010

AbstractIn highland areas worldwide, socioeconomic globalization is progressing urbanization and environmental destruction. Urbanization is caused by socioeconomic globalization of development of transportation, movement or immigration of people, and prevailing market economy. Lifestyle‐related diseases, such as diabetes and hypertension, are increasing worldwide with greater longevity and changes in lifestyles. Highland areas may also be affected by globalization and the people living there may be especially vulnerable. Our objective was to disclose the features of lifestyle‐related diseases and the human aging phenomena of highland people affected by their increasingly urbanized lifestyles by undertaking a detailed geriatric assessment. Our assessment included firstly comparing the prevalence of hypertension and neurobehavioral functions in community‐dwelling Tibetan elderly in Shangri‐la, Yunnan, China (altitude 3,300 m) with Thai elderly in the city of Jing Hong, Yunnan, China (altitude 500 m) and Japanese in Tosa, Kochi, Japan (altitude 300 m). Secondly, differences in the prevalence of hypertension, obesity, and neurobehavioral function were analyzed between people in an urban area, Jiang Tang, and rural areas and in association with their economic status in Nish in Shangri‐la. High prevalences of lifestyle‐related diseases such as hypertension and obesity were shown in highlanders, especially those in an urban area. Geriatric functional ability was associated with economic status. Notwithstanding a higher prevalence of physical disorders and lowered functional abilities, a higher quantitative quality of life was found in Shangri‐la than in Tosa. We concluded that highland‐dwelling people were vulnerable and susceptible to lifestyle‐related diseases resulting from socioeconomic globalization.
Use of a “kickstand” modification for external fixation of lower extremity fractures in children
Authors: Sawyer Jeffrey R. , Kelly Derek M. , Rhodes Leslie N. , Beaty James H. , Terry Canale S. , Warner William C. 
Published: November 2010

Purpose To evaluate and describe the kickstand modification and its use in children with lower extremity fractures. Methods Retrospective review identified eight children in whom the kickstand technique was used during treatment of their lower extremity fractures. The seven boys and one girl had a mean age of 11.8 years. All fractures were caused by high-energy trauma. Five of the eight tibial fractures were open fractures (one type 1, one type 2, and three type 3B), and five of the eight patients had multiple extremity fractures. Results Additional procedures were required in six of the eight children, four of whom had multiple lower extremity fractures. No additional pressure-relieving modalities were used in any patient. The kickstand did not affect the fracture reduction, prevent patient mobilization, or require operative adjustment in any patient, and none had any skin pressure-related complications on the heel of the affected extremity. Conclusion In pediatric patients with lower extremity trauma, the addition of a kickstand to the external fixator provides a simple, inexpensive, lightweight, adjustable, and adaptable method for encouraging elevation of the injured extremity, which facilitates edema control; it also allows easy neurovascular monitoring and wound care.
Common inventory modeling assumptions that fall short: Arborescent networks, Poisson demand, and single‐echelon approximations
Authors: Cattani Kyle D. , Jacobs F. Robert , Schoenfelder Jan 
Published: November 2010

AbstractTraditional multi‐echelon inventory theory focuses on arborescent supply chains that use a central warehouse which replenishes remote warehouses. The remote warehouses serve customers in their respective regions. Common assumptions in the academic literature include use of the Poisson demand process and instantaneous unit‐by‐unit replenishment. In the practitioner literature, single‐echelon approximations are advised for setting safety stock to deal with lead time, demand, and supply variations in these settings. Using data from a U.S. supplier of home improvement products, we find that neither the assumptions from the academic literature nor the approximations from the practitioner literature necessarily work well in practice.In a variation of the strictly arborescent supply chain, the central warehouse at our real company not only replenishes other warehouses but also meets demand from customers in the region near the central warehouse. In this paper, we study this dual‐role central warehouse structure, which we believe is common in practice. Using high and low volume product demand data from this company, we use Monte Carlo simulations to study the impact of (1) the use of a dual‐role centralized warehouse, (2) common demand assumptions made in multi‐echelon research, and (3) single‐echelon approximations for managing a multi‐echelon supply chain. We explore each of these under both centralized and decentralized control logic. We find that the common assumptions of theoretical models impede their usefulness and that heuristics that ignore the actual supply chain structure fail to account for additional opportunities to utilize safety stock more effectively. Researchers should be aware of the gap between standard assumptions in traditional literature and actual practice, and critically evaluate their assumptions to find a reasonable balance between tractability and relevance.
The estrogen receptor alpha‐derived peptide ERα17p (P295‐T311) exerts pro‐apoptotic actions in breast cancer cells in vitro and in vivo, independently from their ERα status
Authors: Pelekanou Vassiliki , Kampa Marilena , Gallo Dominique , Notas George , Troullinaki Maria , Duvillier Hugues , Jacquot Yves , Stathopoulos Efstathios N. , Castanas Elias , Leclercq Guy 
Published: November 2010

In recent years, our knowledge on estrogen receptors (ER) has been modified profoundly with the identification and the deciphering of the role of its protein effectors, as well as with the deeper insight of its molecular structure/function dynamics, characteristics associated with its nucleo‐cytoplasmic‐membrane shuttling properties. Also, significant progress has been made concerning its turn‐over and associated final proteasomal degradation processes. These advances could lead in the near future to the design and the synthesis of novel receptor‐interacting drugs. Recently, a number of receptor‐related peptides acting as specific ER ligands have been identified and extensively studied with respect to their estrogenic/antiestrogenic activities. Among them, ERα17p, a synthetic analog of the P295‐T311 sequence of ERα, has been shown to exert pseudo‐estrogenic effects by interacting in the close vicinity of its hinge region (BF3 domain). Remarkably, this sequence appears as the epicenter of a number of post‐transcriptional modifications as well as of the recruitment of co‐regulators, suggesting that it would play a key role in ERα functions. Here, we provide evidence that ERα17p induces apoptosis in ERα‐positive (MCF‐7, T47D) and ‐negative (MDA‐MB‐231, SK‐BR‐3) breast cancer cells by an ERα‐independent membrane mechanism, triggering major pro‐apoptotic signaling cascades. Finally, ERα17p induces the regression of breast ERα‐negative cancer tumor xenografts, without apparent toxicity, suggesting that it could represent a new attractive tool for the development of future promising therapeutic approaches, and providing a novel insight to ER regulation of cell fate.
Young coconut juice, a potential therapeutic agent that could significantly reduce some pathologies associated with Alzheimer's disease: novel findings
Authors: Radenahmad Nisaudah , Saleh Farid , Sawangjaroen Kitja , Vongvatcharanon Uraporn , Subhadhirasakul Patchara , Rundorn Wilart , Withyachumnarnkul Boonsirm , Connor James R. 
Published: November 2010

Brains from ovariectomised (ovx) rats can display features similar to those observed in menopausal women with Alzheimer's disease (AD), and oestrogen seems to play a key role. Preliminary studies on young coconut juice (YCJ) have reported the presence of oestrogen-like components in it. The aim of the study was to investigate the effects of YCJ on the AD pathological changes in the brains of ovx rats. Rat groups included sham-operated, ovx, ovx+oestradiol benzoate (EB) and ovx+YCJ. Brain sections (4 μm) were taken and were immunostained with β-amyloid (Aβ) 1–42, glial fibrillary acidic protein (GFAP) (an intermediate neurofilament of astrocytes) and Tau-1 antibodies. Aβ 1–42, GFAP and Tau-1 are considered as reliable biomarkers of amyloidosis, astrogliosis and tauopathy (neurofibrillary tangles), respectively, which in turn are characteristic features associated with AD. The serum oestradiol (E2) level was measured using a chemiluminescent immunoassay technique. YCJ restored the serum E2 to levels significantly (P < 0·001) higher than that of the ovx group, and even that of the sham group. Aβ deposition was significantly (P < 0·0001) reduced in the cerebral cortex of the YCJ group, as compared with the ovx group and with the sham and ovx+EB groups (P < 0·01). A similar trend was observed in relation to GFAP expression in the cerebral cortex and to Tau-1 expression in the hippocampus. This is a novel study demonstrating that YCJ could have positive future implications in the prevention and treatment of AD in menopausal women.
Helminth infections of wild boars (Sus scrofa) in the Bursa province of Turkey
Authors: Senlik B. , Cirak V.Y. , Girisgin O. , Akyol C.V. 
Published: November 2010

AbstractThe present study aimed to investigate the status of helminth infections in wild boars in the Bursa province of Turkey. For this purpose, during 2007–2008, 27 wild boars were necropsied and examined for helminths. Individual samples of tongue and diaphragm from 27 necropsied wild boars and an additional 22 tongue and diaphragm samples provided by hunters were examined by trichinoscopy and artificial digestion for Trichinella spp. larvae. Twenty animals (74%) were identified as being infected with at least one helminth species. Twelve species of helminths were detected, with the following prevalence rates: Metastrongylus apri (59%), Metastrongylus salmi (52%), Metastrongylus pudendotectus (52%), Dicrocoelium dendriticum (33%), Globocephalus urosubulatus (22%), Macracanthorhynchus hirudinaceus (19%), Gongylonema pulchrum (11%), Physocephalus sexalatus (7%), Trichuris suis (7%), Ascarops strongylina (4%), Hyostrongylus rubidus (4%) and Taenia hydatigena larvae (4%). Generally, lungworms were the predominant helminths. The highest mean abundance was observed for M. pudendotectus, and the lowest was determined for T. hydatigena larvae. Significant differences in the prevalence and intensity were found for D. dendriticum with respect to host age and sex, respectively. The mean intensity of M. pudendotectus was significantly influenced by the sex and age of the wild boars. This study is the first report describing the presence of M. salmi, M. pudendotectus, D. dendriticum,G. urosubulatus, M. hirudinaceus, P. sexalatus, A. strongylina and H. rubidus in wild boars in Turkey. All analysed muscle samples were negative for Trichinella spp. larvae.
CONSTITUTION AND FUNDAMENTAL LAW: THE LESSON OF CLASSICAL ATHENS
Authors: Lewis John David 
Published: November 2010

AbstractThe question of what constitutions should do is deeply connected to what constitutions are. In the American founding conception, a constitution was a fundamental law, hierarchically superior to the decisions of the legislature, and intended to act as a restraint on legislative action. Despite the massive gulf between the ancient Greeks and the Americans, classical Athens offers an important lesson about how the failure to recognize fundamental laws can lead to catastrophic consequences. The evidence suggests that the Athenians understood the need for conceptual, procedural, and institutional distinctions between the fundamental laws and the more specific decrees of the governing institutions. The Athenian and American experiences also suggest that certain philosophical positions conditioned their understanding of their fundamental laws, and guided the practices that followed from that understanding.
FOOT VOTING, POLITICAL IGNORANCE, AND CONSTITUTIONAL DESIGN
Authors: Somin Ilya 
Published: November 2010

AbstractThe strengths and weaknesses of federalism have been debated for centuries. But one major possible advantage of building decentralization and limited government into a constitution has been largely ignored in the debate so far: its potential for reducing the costs of widespread political ignorance. The argument of this paper is simple, but has potentially important implications: Constitutional federalism enables citizens to “vote with their feet,” and foot voters have much stronger incentives to make well-informed decisions than more conventional ballot box voters. The informational advantage of foot voting over ballot box voting suggests that decentralized federalism can increase citizen welfare and democratic accountability relative to policymaking in a centralized unitary state.Ballot box voters have strong incentives to be “rationally ignorant” about the candidates and policies they vote on because the chance that any one vote will have a decisive impact on an electoral outcome is vanishingly small. For the same reason, they also have little or no incentive to make good use of the information they do possess. By contrast, “foot voters” choosing a jurisdiction in which to reside have much stronger incentives to acquire information and use it rationally; the decisions they make are individually decisive.
PLURALIST CONSTITUTIONALISM
Authors: Galston William A. 
Published: November 2010

AbstractThis essay explores the ways in which a broadly pluralist outlook can help illuminate longstanding issues of constitutional theory and practice. It begins with a common-sense understanding of pluralism as the diversity of observed practices within a general category (section 2). It turns out that many assumptions Americans and others often make about constitutional essentials are valid only locally but not generically. The essay then turns to pluralism in a more technical and philosophical sense—specifically, the account of value pluralism adumbrated by Isaiah Berlin and developed by his followers. Section 3 sketches this version of pluralism, and section 4 brings it to bear on a range of familiar constitutional issues. In the process, a distinction emerges between, on the one hand, areas of variation among constitutions and, on the other, some general truths about political life that define core constitutional functions. The essay concludes (section 5) with some brief reflections on the normative thrust of pluralist constitutional theory—in particular, a presumption in favor of the maximum accommodation of individual and group differences consistent with the maintenance of constitutional unity and civic order.
Is there enough habitat for reintroduced populations of the Lesser Kestrel? A case study in eastern Spain
Authors: PÉREZ IRENE , NOGUERA JOSÉ CARLOS , MÍNGUEZ EDUARDO 
Published: November 2010

SummaryThe Lesser Kestrel Falco naumanni is one of the most endangered birds in Europe. Spanish populations have suffered large declines and disappeared from large areas of former distribution, thus leading to many reintroduction programmes. One of the main factors that could affect the population growth of reintroduced populations is the availability of suitable habitat for breeding and foraging. We investigated whether nest site availability is a limiting factor for a newly established population of Lesser Kestrels in eastern Spain. We developed univariate models to understand the relationship between building characteristics (area, height, roof condition, etc.) and occupancy and abundance of Lesser Kestrels, and multivariate models to predict the availability of nest-sites. Our results showed that the species selected medium-sized buildings with extensive land use in the surrounding area and an absence of trees. In addition, Lesser Kestrel abundance was explained by roof condition and distance to the nearest building. Multivariate models predicted that most of the buildings were not suitable for nesting by Lesser Kestrels and thus population growth may be limited due to lack of nest sites. Lack of suitable nest sites, conspecific attraction and Allee effects are all processes that may be limiting, resulting in the low population and colony sizes that were found and predicted. Based on this, we recommend the provision of nest boxes, the use of special tiles and the construction of breeding towers to improve building quality and therefore increase colony size. We also critically question the use of reintroduction projects to restore locally extinct populations for two reasons. First in this case the reintroduced population is near some larger colonies and there is a strong tendency for Lesser Kestrels to move from small to large colonies. Secondly, in a general strategy for the conservation of Lesser Kestrels, conservation of the main colonies is the priority rather than dedicating human and economic resources on manipulative actions for the establishment of new colonies.