bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the performance of random‐coefficient pattern‐mixture models for non‐ignorable drop‐out
Authors: Demirtas Hakan , Schafer Joseph L. 
Published: July 2003

AbstractRandom‐coefficient pattern‐mixture models (RCPMMs) have been proposed for longitudinal data when drop‐out is thought to be non‐ignorable. An RCPMM is a random‐effects model with summaries of drop‐out time included among the regressors. The basis of every RCPMM is extrapolation. We review RCPMMs, describe various extrapolation strategies, and show how analyses may be simplified through multiple imputation. Using simulated and real data, we show that alternative RCPMMs that fit equally well may lead to very different estimates for parameters of interest. We also show that minor model misspecification can introduce biases that are quite large relative to standard errors, even in fairly small samples. For many scientific applications, where the form of the population model and nature of the drop‐out are unknown, interval estimates from any single RCPMM may suffer from undercoverage because uncertainty about model specification is not taken into account. Copyright © 2003 John Wiley & Sons, Ltd.
Two bivariate geometrically defined reference regions with applications to male reproductive hormones and human growth
Authors: Petersen Jørgen Holm 
Published: July 2003

AbstractTwo conceptually simple two‐dimensional reference charts are described. The charts are characterized analytically, but also by geometric properties that are easily communicated to subject‐matter researchers – the users of such charts. For both charts, the proposed estimators are non‐parametric, so no distributional assumptions are needed about the two‐dimensional response. An important example that will serve to motivate and illustrate one of the charts is the study of the human reproductive hormones Inhibin B and FSH. A low Inhibin B concentration combined with a high FSH concentration is an indication that something may be wrong in the seminal cells which produce semen, and such measurements help in the process of distinguishing between different reasons for infertility. The aim in the study of the human reproductive hormones was to give a two‐dimensional reference curve for the non‐normally distributed hormone measurements while taking into account that some measurements were left‐censored because of a detection limit in the assay used to measure the concentrations. Copyright © 2003 John Wiley & Sons, Ltd.
Separation of individual‐level and cluster‐level covariate effects in regression analysis of correlated data
Authors: Begg Melissa D. , Parides Michael K. 
Published: July 2003

AbstractThe focus of this paper is regression analysis of clustered data. Although the presence of intracluster correlation (the tendency for items within a cluster to respond alike) is typically viewed as an obstacle to good inference, the complex structure of clustered data offers significant analytic advantages over independent data. One key advantage is the ability to separate effects at the individual (or item‐specific) level and the group (or cluster‐specific) level. We review different approaches for the separation of individual‐level and cluster‐level effects on response, their appropriate interpretation and give recommendations for model fitting based on the intent of the data analyst. Unlike many earlier papers on this topic, we place particular emphasis on the interpretation of the cluster‐level covariate effect. The main ideas of the paper are highlighted in an analysis of the relationship between birth weight and IQ using sibling data from a large birth cohort study. Copyright © 2003 John Wiley & Sons, Ltd.
Architecting and implementing distributed Web applications using the graph‐oriented approach
Authors: Cao Jiannong , Ma Xiaoxing , Chan Alvin T. S. , Lu Jian 
Published: July 2003

AbstractThis paper presents a graph‐oriented framework, called WebGOP, for architecture modeling and programming of Web‐based distributed applications. WebGOP is based on the graph‐oriented programming (GOP) model, under which the components of a distributed program are configured as a logical graph and implemented using a set of operations defined over the graph. WebGOP reshapes GOP with a reflective object‐oriented design, which provides powerful architectural support in the World Wide Web environment. In WebGOP, the architecture graph is reified as an explicit object which itself is distributed over the network, providing a graph‐oriented context for the execution of distributed applications. The programmer can specialize the type of graph to represent a particular architecture style tailored for an application. WebGOP also has built‐in support for flexible and dynamic architectures, including both planned and unplanned dynamic reconfiguration of distributed applications. We describe the WebGOP framework, a prototypical implementation of the framework on top of SOAP, and a performance evaluation of the prototype. The prototype demonstrated the feasibility of our approach. Results of the performance evaluation showed that the overhead introduced by WebGOP over SOAP is reasonable and acceptable. Copyright © 2003 John Wiley & Sons, Ltd.
A security framework for reflective Java applications
Authors: Caromel Denis , Vayssière Julien 
Published: July 2003

AbstractThe advent of component‐based reflective applications raises the issue of protecting baselevel components from the actions performed by metalevel components. However, by their very nature, reflective applications are far more difficult to secure than non‐reflective applications, which certainly explains why the problem has received very little attention so far. In this paper we present a security framework for enforcing access control between metalevel components and the baselevel components they reflect on. Rather than designing a new security architecture from scratch, we extend the standard security architecture of Java to provide security for a fully‐functional proxy‐based MOP for Java. We implement a number of well‐known meta‐level behaviors and study their security requirements, the results of which support our design choices. Copyright © 2003 John Wiley & Sons, Ltd.
DIKE: a system supporting the semi‐automatic construction of cooperative information systems from heterogeneous databases
Authors: Palopoli Luigi , Terracina Giorgio , Ursino Domenico 
Published: July 2003

AbstractIn this paper we present DIKE, a system supporting the semi‐automatic construction of cooperative information systems from heterogeneous databases. The input of DIKE consists of the set of databases to belong to the cooperative system. First, DIKE constructs a data repository representing a structured, integrated and consistent description of the information stored in the input databases. The data repository thus constructed is then used as the core structure of a mediator‐like module supporting the user‐friendly integrated access to available data resources. The core of DIKE is the extraction and exploitation of the inter‐schema knowledge (in the form of inter‐schema properties) relative to the involved database schemas. Copyright © 2003 John Wiley & Sons, Ltd.
Substituting outline fonts for bitmap fonts in archived PDF files
Authors: Probets S. G. , Brailsford D. F. 
Published: July 2003

AbstractAs collections of archived digital documents continue to grow the maintenance of an archive, and the quality of reproduction from the archived format, become important long‐term considerations. In particular, Adobe's portable document format (PDF) is now an important ‘final form’ standard for archiving and distributing electronic versions of technical documents. It is important that all embedded images in the PDF, and any fonts used for text rendering, should at the very minimum be easily readable on screen. Unfortunately, because PDF is based on PostScript technology, it allows the embedding of bitmap fonts in Adobe Type 3 format as well as higher‐quality outline fonts in TrueType or Adobe Type 1 formats. Bitmap fonts do not generally perform well when they are scaled and rendered on low‐resolution devices such as workstation screens.The work described here investigates how a plug‐in to Adobe Acrobat enables bitmap fonts to be substituted by corresponding outline fonts using a checksum matching technique against a canonical set of bitmap fonts, as originally distributed. The target documents for our initial investigations are those PDF files produced by LATEX systems when set up in a default (bitmap font) configuration. For all bitmap fonts where recognition exceeds a certain confidence threshold replacement fonts in Adobe Type 1 (outline) format can be substituted with consequent improvements in file size, screen display quality and rendering speed. The accuracy of font recognition is discussed together with the prospects of extending these methods to bitmap‐font PDF files from sources other than LATEX. Copyright © 2003 John Wiley & Sons, Ltd.
Pathology of lumbar nerve root compression Part 1: Intraradicular inflammatory changes induced by mechanical compression
Authors: Kobayashi Shigeru , Yoshizawa Hidezo , Yamada Shuuichi 
Published: August 2003

AbstractStudy design: This study is to investigate the intraradicular inflammation induced by mechanical compression using in vivo model.Objectives: The relationship between the intraradicular edema and nerve fiber degeneration induced by mechanical compression was determined in the nerve root.Summary of background data: Recently some studies reported that mechanical compression increased microvascular permeability of the endoneurial capillaries and resulted in an intraradicular inflammation. These changes may be an important factor of the pathogenesis of radiculopathy. However, the natural courses of the intraradicular inflammation after mechanical compression are still poorly understood.Methods: In dogs, laminectomy was performed at L7 and the seventh nerve root was exposed to compression at 7.5 gram force (gf) clipping power. The animals were evaluated at 1 and 3 weeks after clipping. After the appropriate period of nerve root compression, Evans blue albumin (EBA) was injected intravenously. The nerve root sections were divided into two groups. The sections were used to investigate the status of the blood–nerve barrier function under the fluorescence microscope. The other sections were used for light and transmission electron microscopic study.Results: After 1 and 3 weeks, intraradicular edema was observed not only at the site of compression but also in the peripheral zone of a compressed anterior root and in the central zone of a compressed posterior root. The evidence of active Wallerian degeneration was also seen in the area of intraradicular edema. In addition, the nerve roots showing Wallerian degeneration were infiltrated by inflammatory cells, such as macrophages and mast cells.Conclusions: Inflammatory reaction, such as Wallerian degeneration, breakdown of blood–nerve barrier and appearance of macrophage, may be deeply involved in radiculitis arising from mechanical compression, and these factors seem to be important in the manifestation of radiculopathy. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Long stemmed total knee arthroplasty with interlocking screws: A computational bone adaptation study
Authors: Nyman Jeffry S. , Hazelwood Scott J. , Rodrigo Juan J. , Martin R. Bruce , Yeh Oscar C. 
Published: August 2003

AbstractThe ability of an interlocking screw fixation technique to minimize bone loss related to stress shielding in the tibia was investigated and compared to the abilities of cement and press‐fit fixation. Full bony ingrowth has been associated with greater stress shielding than partial ingrowth; therefore, the effect of intimate bonding of the stem to bone on subsequent bone loss was also studied. A damage‐ and disuse‐based remodeling theory was coupled with a two‐dimensional finite element model of the tibia to predict changes in bone remodeling following long stemmed total knee arthroplasty (TKA) for four different fixation techniques (cement, press‐fit, interlock with bony ingrowth, and interlock without bony ingrowth). Remodeling changes commenced with the model state variables—bone area fraction, mechanical stimulus, damage, and remodeling activity—at steady‐state values predicted by the intact tibia simulation. After TKA and irrespective of fixation technique, the model predicted elevated remodeling due to disuse, in which more bone was removed than replenished. In regions below the tibial tray and along the cortices, the interlocking stem with full bony ingrowth and the cemented stem caused the least amount of bone loss. An interlocking stem with a smooth, matted finish did not reduce the bone loss associated with interlocking fixation. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Neuropeptides in anterior pituitary development
Authors: Cimini Vincenzo 
Published: July 2003

AbstractRecent studies using biotechnological methods have achieved significant advances in our knowledge of molecular mechanisms underlying pituitary gland development and the differentiation of pituitary cytotypes. A large number of neuropeptides have been reported in the adult pituitary gland as well as in the central and peripheral nervous system. The early presence of neuropeptides during pituitary development is reviewed here. Neuromedin U (NmU), galanin and the polypeptide 7B2 have been localised to different endocrine cells of the gland. Their expression seems to be manifold even though it is temporally and spatially regulated. There is now firm immunocytochemical evidence that neuropeptides are present during morphogenesis of the pituitary and can be present simultaneously with all pituitary hormones.
Lead toxicosis in cats—a review
Authors: Knight TE , Kumar MSA 
Published: August 2003

Although the incidence of lead toxicosis in small animals continues to decrease, it remains a significant malady. We have reviewed the literature of the past 45 years, which revealed 70 cases involving cats. Sources, signs, diagnosis, pathology and treatment of feline lead toxicosis are reviewed. In 84% of these cases the source of lead was old paint usually from home renovation. The most common signs in cats are anorexia, vomiting, and seizures. The younger individuals seem more likely to show CNS signs. Since signs are often vague, lead toxicosis may be significantly under diagnosed in cats. The gold standard of diagnostic tests is blood lead concentration, although it does not necessarily correlate with total body burden of lead or with metabolic effects including clinical signs. Diagnostic tests including erythropoietic protoporphyrin (EPP), urine aminolevulinic acid, and others are discussed. Gross findings on necropsy are few and include a yellow-brown discoloration of the liver often with a nutmeg-like appearance. Histological examination may reveal pathognomonic inclusion bodies in liver and renal tissues. Characteristic histological changes in the CNS include neuronal necrosis and demyelination. Treatment of lead toxicosis in cats, as in any species, involves removing the exposure, decontaminating the individual and the environment, supportive care and chelation therapy. The most recently available chelator is succimer (meso 2,3-dimercaptosuccinic acid). Succimer given orally is well tolerated and has a wide margin of safety. A high index of suspicion of lead toxicosis is warranted in cats since they often present with vague and non-specific signs. With any consistent history owners need to be asked about home renovation. Early diagnosis and treatment affords a good prognosis.
RAMASD: a semi-automatic method for designing agent organisations
Authors: KARAGEORGOS ANTHONY , MEHANDJIEV NIKOLAY , THOMPSON SIMON 
Published: August 2003

Designing realistic multi-agent systems is a complex process, which involves specifying not only the functionality of individual agents, but also the authority relationships and lines of
communication existing among them. In other words, designing a multi-agent system refers to designing an agent organisation. Existing methodologies follow a wide variety of approaches to designing agent organisations, but they do not provide adequate support for the decisions involved in moving from analysis to design. Instead, they require designers to make ad hoc design decisions while working at a low level of abstraction.We have developed RAMASD (Role Algebraic Multi-Agent System Design), a method for semi-automatic design of agent organisations based on the concept of role models as first-class design
constructs. Role models represent agent behaviour, and the design of the agent system is done by systematically allocating roles to agents. The core of this method is a formal model of basic relations between roles, which we call role algebra. The semantics of this role-relationships model are formally defined using a two-sorted algebra.In this paper, we review existing agent system
design methodologies to highlight areas where further work is required, describe how our method can address some of the outstanding issues and demonstrate its application to a case study involving
telephone repair service teams.
J. Robert Oppenheimer: Proteus Unbound
Authors: Schweber Silvan S. 
Published: August 2003

ArgumentJ. Robert Oppenheimer was a complex person. His work in physics during the 1930s, at Los Alamos during the 1940s, and as governmental advisor in the immediate postwar period, gave him a deep sense of connection with communities that had distinctive purposes. But he found it difficult to conceive an overall creative vision for himself or to devise a compelling objective for the community he belonged to if one had not been formulated at the time he assumed its leadership. I analyze the reasons for his successes: the vision and demands of physics during the 1930s, the make-up of Los Alamos, and the challenges of the postwar atomic world. In each of these enterprises he assumed a distinctive role and came to represent a distinctive persona – but he could not integrate his activities into a coherent whole that might be a model for the intellectual in the new world he had helped to shape.
Objectivity and the Scientist: Heisenberg Rethinks
Authors: Carson Cathryn 
Published: August 2003

ArgumentObjectivity has been constitutive of the modern scientific persona. Its significance has depended on its excision of standpoint, which has legitimated the scientist epistemically and sociopolitically at once. But if the nineteenth century reinforced those paired effects, the twentieth century brought questioning of both. The figure of Werner Heisenberg (1901–1976) puts the latter process on display. From the Kaiserreich to the Federal Republic of Germany, between quantum mechanics and interest group politics, his evolution shows an increasing openness to perspectival pluralism, together with an attempt to save some form of objectivity as discursive coherence. Heisenberg’s self-understanding and the reactions of his publics display the transmutation of the persona as objectivity was rethought. By the end of the day, speaking “as a scientist” would mean something different from what it had at the start.
Charles Darwin as a Celebrity
Authors: Browne Janet 
Published: August 2003

ArgumentSeveral recent works in sociology examine the manufacture of public identities through the notion of celebrity. This paper explores the imagery of Charles Darwin as a nineteenth-century scientific celebrity by comparing the public character deliberately manufactured by Darwin and his friends with images constructed by the public as represented here by caricatures in humorous magazines of the era. It is argued that Darwin’s outward persona drew on a subtle tension between public and private. The boundaries between public and private were blurred by the ritual of Darwin “showing” himself in the flesh, either at home to visitors or, more rarely, on public occasions. The reputation for privacy and illness that he built up added materially to this public face. By contrast, caricatures tended to depict him as an ape. These apish representations played a significant role in associating Darwin, rather than any other thinker, with the notion of evolution, and in creating an alternative public persona over which he had no direct control.
Skulls, Brains, and Memorial Culture: On Cerebral Biographies of Scientists in the Nineteenth Century
Authors: Hagner Michael 
Published: August 2003

ArgumentIn this paper I will argue that the scientific investigation of skulls and brains of geniuses went hand in hand with hagiographical celebrations of scientists. My analysis starts with late-eighteenth century anatomists and anthropologists who highlighted quantitative parameters such as the size and weight of the brain in order to explain intellectual differences between women and men and Europeans and non-Europeans, geniuses and ordinary persons. After 1800 these parameters were modified by phrenological inspections of the skull and brain. As the phrenological examination of the skulls of Immanuel Kant, Wilhelm Heinse, Arthur Schopenhauer and others shows, the anthropometrical data was interpreted in light of biographical circumstances. The same pattern of interpretation can be found in non-phrenological contexts: Reports about extraordinary brains were part of biographical sketches, mainly delivered in celebratory obituaries. It was only in this context that moral reservations about dissecting the brains of geniuses could be overcome, which led to a more systematic investigation of brains of geniuses after 1860.
Geometric numerical integration illustrated by the Störmer–Verlet method
Authors: Hairer Ernst , Lubich Christian , Wanner Gerhard 
Published: August 2003

The subject of geometric numerical integration deals with numerical integrators that preserve geometric properties of the flow of a differential equation, and it explains how structure preservation leads to improved long-time behaviour. This article illustrates concepts and results of geometric numerical integration on the important example of the Störmer–Verlet method. It thus presents a cross-section of the recent monograph by the authors, enriched by some additional material.After an introduction to the Newton–Störmer–Verlet–leapfrog method and its various interpretations, there follows a discussion of geometric properties: reversibility, symplecticity, volume preservation, and conservation of first integrals. The extension to Hamiltonian systems on manifolds is also described. The theoretical foundation relies on a backward error analysis, which translates the geometric properties of the method into the structure of a modified differential equation, whose flow is nearly identical to the numerical method. Combined with results from perturbation theory, this explains the excellent long-time behaviour of the method: long-time energy conservation, linear error growth and preservation of invariant tori in near-integrable systems, a discrete virial theorem, and preservation of adiabatic invariants.