bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of the precision and sensitivity to change of different approaches to assess cartilage loss by quantitative MRI in a longitudinal multicentre clinical trial in patients with knee osteoarthritis
Authors: Raynauld Jean-Pierre , Martel-Pelletier Johanne , Abram François , Dorais Marc , Haraoui Boulos , Choquette Denis , Bias Peter , Emmert Karl H , Laufer Stefan , Pelletier Jean-Pierre 
Published: November 2008

Abstract
Introduction
Cartilage thickness and volume loss measurements using quantitative magnetic resonance imaging (qMRI) are suggested to detect significant cartilage changes over short time intervals. We aimed to compare these two different approaches looking at the global knee and subregions, using data from an osteoarthritis (OA) multicentre randomised clinical trial.

Methods
Three hundred and fifty-five patients with symptomatic knee OA were recruited for a two-year, double-blind, randomised clinical trial evaluating the effect of 200 mg licofelone twice daily and 500 mg naproxen twice daily on cartilage loss, and 301 patients had baseline MRI. MRIs were performed at baseline, 6, 12 and 24 months. Cartilage volume and thickness in the global joint, medial and lateral compartments, and central weight-bearing subregions of the medial and lateral femoral condyles and tibial plateaus were analysed. Data were analysed for the mean value imputed for intent-to-treat (ITT-MVI) and statistical analyses were performed using two-sample Student's t-test.

Results
Cartilage mean thickness loss in the global joint, lateral and medial compartments, as well as in medial compartments stratified according to patients with or without meniscal extrusion, was significantly less in the licofelone compared with the naproxen group at 12 and 24 months. Interestingly, these data were similar to those found when using cartilage volume loss as an outcome. Although greater cartilage volume and mean thickness loss was seen in central weight-bearing subregions of the medial and lateral compartments compared with the whole compartment and also in patients with meniscal lesions/extrusion, suggesting good sensitivity to change, its high standard deviation precluded for the condyles a high statistical power and abrogated statistically significant differences between the treatment groups.

Conclusions
These data demonstrate that both the measurement of cartilage thickness and that of cartilage volume provide the same level of sensitivity to estimate cartilage loss in a clinical trial. However, the potential of gaining statistical power with the use of thickness/volume change in knee subregions as an outcome seems negated by high inter-patient variability. Moreover, there is no superiority in statistical power by selecting patients with meniscal extrusion.
Approach to the Patient with a Cytologically Indeterminate Thyroid Nodule
Authors: Alexander Erik K. 
Published: November 2008

Background: Fine-needle aspiration remains the primary diagnostic intervention for the evaluation of most thyroid nodules larger than 1–1.5 cm. Although most aspirates provide diagnostic cytology, approximately 15–25% will be classified indeterminate (often referred to as follicular neoplasm, suspicious for carcinoma, or atypical). In such cases, abnormal cellular findings preclude interpretation of benignity, although only a minority will prove cancerous upon final histopathology. Nonetheless, patients with indeterminate aspirates are commonly referred for consideration of hemi- or near-total thyroidectomy. Recently, improved understanding and novel investigation of clinical, radiological, cytological, and molecular factors has allowed improved stratification of cancer risk.Conclusion: Although surgery continues to be commonly recommended, strategies for such patients should increasingly seek to define treatment based on the estimation of an individual’s thyroid cancer risk in comparison with associated operative risk and morbidity. In doing so, the rate of unnecessary surgical procedures and associated complications can be reduced.
Mechanism and rate of glucose absorption differ between an Australian honeyeater (Meliphagidae) and a lorikeet (Loriidae)
Authors: Napier Kathryn R. , McWhorter Todd J. , Fleming Patricia A. 
Published: October 2008

SUMMARYEfficient mechanisms of glucose absorption are necessary for volant animals as a means of reducing mass during flight: they speed up gut transit time and require smaller volume and mass of gut tissue. One mechanism that may be important is absorption via paracellular (non-mediated) pathways. This may be particularly true for nectarivorous species which encounter large quantities of sugar in their natural diet. We investigated the extent of mediated and non-mediated glucose absorption in red wattlebirds Anthochaera carunculata (Meliphagidae) and rainbow lorikeets Trichoglossus haematodus (Loriidae) to test the hypothesis that paracellular uptake accounts for a significant proportion of total glucose uptake in these species. We found that routes of glucose absorption are highly dynamic in both species. In lorikeets, absorption of l-glucose(non-mediated uptake) is slower than that of d-glucose (mediated and non-mediated uptake), with as little as 10% of total glucose absorbed by the paracellular pathway initially (contrasting previous indirect estimates of∼0%). Over time, however, more glucose may be absorbed via the paracellular route. Glucose absorption by both mediated and non-mediated mechanisms in wattlebirds occurred at a faster rate than in lorikeets, and wattlebirds also rely substantially on paracellular uptake. In wattlebirds, we recorded higher bioavailability of l-glucose (96±3%)compared with d-glucose (57±2%), suggesting problems with the in vivo use of radiolabeled d-glucose. Further trials with 3-O-methyl-d-glucose revealed high bioavailability in wattlebirds (90±5%). This non-metabolisable glucose analogue remains the probe of choice for measuring uptake rates in vivo, especially in birds in which absorption and metabolism occur extremely rapidly.
On Generalized Reciprocal Diagrams for Self-Stressed Frameworks
Authors: Micheletti Andrea 
Published: November 2008

We present the duality between edge lengths and axial forces in self-stressed frameworks, upon which are based reciprocal diagrams, introduced by Maxwell and Cremona in the nineteenth century. The main concepts and principles are simplified by using a graph theoretic approach. We describe some unusual orthogonality relations, involving lengths, axial forces and their rates of change. Reciprocal diagrams, which exist for frameworks with underlying planar graph, are extended also to the non-planar case by introducing a new criterion. When this criterion can be applied, different reciprocals can be obtained as symmetric frameworks. The same criterion can also be applied to planar cases giving new reciprocals as a result. Although reciprocal diagrams cannot be obtained for all self-stressed frameworks, the presented duality always holds and it provides useful insights for design and form-finding purposes.
Numerical Solution of Linear Equations Arising in Markov Chain Models
Authors: Heyman Daniel P. , Reeves Alyson 
Published: October 2008

We examine several methods for numerically solving linear equations that arise in the study of Markov chains. These methods are Gaussian elimination, state-reduction, closed-form matrix solutions, and some hybrid methods. The emphasis is on moments of first-passage times and times to absorption. We compare the methods on the basis of accuracy and computation. We conclude that state-reduction is the most accurate and that the matrix solutions have the least computation time. INFORMS Journal on Computing, ISSN 1091-9856, was published as ORSA Journal on Computing from 1989 to 1995 under ISSN 0899-1499.
Column Generation Methods for Probabilistic Logic
Authors: Jaumard Brigitte , Hansen Pierre , Poggi de Aragão Marcus 
Published: October 2008

Nilsson recently introduced a rigorous semantic generalization of logic in which the truth values of sentences are probability values. This led to state precisely several basic problems of artificial intelligence, a paradigm of which is probabilistic satisfiability (PSAT): determine, given a set of clauses and probabilities that these clauses are true, whether these probabilities are consistent. We consider several extensions of this model involving intervals on probability values, conditional probabilities and minimal modifications of probability values to ensure satisfiability. Investigating further an approach of G. Georgakopoulos, D. Kavvadias and C. H. Papadimitriou, we propose a column generation algorithm which allows to solve exactly all these extensions. Computational experience shows that large problems, with up to 140 variables and 300 clauses, may be solved in reasonable time. INFORMS Journal on Computing, ISSN 1091-9856, was published as ORSA Journal on Computing from 1989 to 1995 under ISSN 0899-1499.
Incremental Linear Constraint Solving and Detection of Implicit Equalities
Authors: Stuckey Peter J. 
Published: October 2008

The incremental linear constraint satisfaction problem consists of repeatedly solving the satisfiability problem for a growing set of linear constraints. This problem is important to constraint logic programming systems where constraints are discovered one at a time and added to a current constraint set, and the satisfiability of this constraint set must be known at all times. Implicit equalities of a system of constraints are inequality constraints that are satisfied as an equality in all solutions of the system of constraints. Detecting implicit equalities is important in determining the minimal (canonical) representation of a system of linear constraints. In incremental constraint solving systems detecting implicit equalities provides information that can simplify further constraint solving. We present an algorithm which efficiently solves the incremental linear constraint satisfaction problem and detects all the implicit equalities present in the constraints. The algorithm forms a basis for the inequality constraint solver in the CLP(ℜ) system. INFORMS Journal on Computing, ISSN 1091-9856, was published as ORSA Journal on Computing from 1989 to 1995 under ISSN 0899-1499.
Fast Heuristics for Large Geometric Traveling Salesman Problems
Authors: Reinelt Gerhard 
Published: October 2008

Very frequently in practical applications we are faced with large or very large scale traveling salesman problems where the number of cities may range from several hundreds or thousands up to even millions. Due to timing restrictions in the production process there may be situations where good approximative solutions to an instance of the traveling salesman problem have to be found very fast, and where it is not feasible to call even O(n2) time procedures too often. In this paper we discuss several ideas to handle such large traveling salesman problems under time restrictions. We will consider Euclidean traveling salesman problems in the plane and show how their geometric structure can be exploited to derive fast heuristics. INFORMS Journal on Computing, ISSN 1091-9856, was published as ORSA Journal on Computing from 1989 to 1995 under ISSN 0899-1499.
Optimal Balanced Assignments and a Parallel Database Application
Authors: Ghandeharizadeh Shahram , Meyer Robert R. , Schultz Gary L. , Yackel Jonathan 
Published: October 2008

In parallel database systems, distribution of the data among the processors has a significant impact on the response time and throughput of the system. The benefits of parallelism (using multiple processors to execute a query) must be balanced against its costs (communication, startup, and termination overhead). We formalize the problem of minimizing overhead while partitioning data uniformly across the processors. We derive lower bounds on these combinatorial problems and demonstrate how processors may be optimally assigned so as to achieve these lower bounds for a number of problem classes. INFORMS Journal on Computing, ISSN 1091-9856, was published as ORSA Journal on Computing from 1989 to 1995 under ISSN 0899-1499.
Commentary—A Survival Guide for Parallel Simulation
Authors: Bagrodia Rajive 
Published: October 2008

The comprehensive article by Fujimoto clearly outlines the path that parallel simulation must follow in the future. To paraphrase a winning slogan from the recent presidential elections—“The tools, stupid.” This paper elaborates on Fujimoto's insightful observations on what is required to make parallel simulation more accessible to the discrete event simulation community and presents experiences derived from the author's research to reinforce the conclusions. INFORMS Journal on Computing, ISSN 1091-9856, was published as ORSA Journal on Computing from 1989 to 1995 under ISSN 0899-1499.
Commentary—The Silver Bullet
Authors: Reynolds Paul F. 
Published: October 2008

When addressing acceptance of a parallel computing technology by the general simulation community, the issue of performance cannot be overlooked and is difficult to overexaggerate. So, how does this relate to Fujimoto's paper? Fujimoto identifies “easing the amount of work and expertise required to parallelize simulation applications” as his primary point of departure and focuses on four silver bullets. “Alleviating concerns about performance” is not among them. Yet, if there is a silver bullet, this is it. What I mean by “alleviating performance concerns” is this: if an environment existed where simulationists could develop parallel simulations with automated support for difficult tasks such as synchronization and communication, and the acceptability of the performance of the resulting simulation execution did not hinge on the performance of the automated portions, then performance concerns have been alleviated. Ideally, the performance of the entire simulation would be acceptable, but programmers can be finicky. Later I employ a borrowed virtual memory analogy to clarify my goal. The difference between what Fujimoto and I consider important is not a matter of content as much as it is a matter of focus. I propose an ideal environment, where the environment is a vehicle for expressing my goals about alleviating performance concerns. Fujimoto discusses languages and identifies requirements that would make the languages better. Both of us conclude by pinpointing similar needs for different reasons. I contend that Fujimoto's presentation leaves the reader with too vague a focus. Many of the issues about languages, application libraries and the like can wait. The research focus needs to be on one central issue: alleviate performance concerns. Solve that and the rest will follow. In the remainder of this commentary, I discuss the limitations of Fujimoto's silver bullets as goals unto themselves and then elaborate on the issues involved in addressing performance concerns and discuss why this issue is central. INFORMS Journal on Computing, ISSN 1091-9856, was published as ORSA Journal on Computing from 1989 to 1995 under ISSN 0899-1499.
Commentary—Practical Parallel Discrete Event Simulation
Authors: Unger Brian W. , Cleary John G. 
Published: October 2008

The feature article addresses issues that are now of crucial importance to this field. Model development for efficient parallel execution is too difficult. Our initial goal at Jade was to create a parallel simulation environment that could be used to solve a wide variety of practical problems. Fujimoto's paper outlines many of the reasons why we have not yet achieved this goal. Our experience at Jade supports Fujimoto's statement that it typically takes “highly skilled experts” to develop models for real applications that can achieve significant speedup due to parallelism. Most of the reasons he presents for this unfortunate situation also agree with our experience. However, we believe there are some important differences in how these difficulties can be addressed. An approach to the design of efficient parallel models is sketched below. This discussion identifies four key indicators of performance and suggests adding one more silver bullet to Fujimoto's list: tools that support the incremental development of efficient models. INFORMS Journal on Computing, ISSN 1091-9856, was published as ORSA Journal on Computing from 1989 to 1995 under ISSN 0899-1499.
Genetic Algorithms for Combinatorial Optimization: The Assemble Line Balancing Problem
Authors: Anderson Edward J. , Ferris Michael C. 
Published: October 2008

Genetic algorithms are one example of the use of a random element within an algorithm for combinatorial optimization. We consider the application of the genetic algorithm to a particular problem, the Assembly Line Balancing Problem. A general description of genetic algorithms is given, and their specialized use on our test-bed problems is discussed. We carry out extensive computational testing to find appropriate values for the various parameters associated with this genetic algorithm. These experiments underscore the importance of the correct choice of a scaling parameter and mutation rate to ensure the good performance of a genetic algorithm. We also describe a parallel implementation of the genetic algorithm and give some comparisons between the parallel and serial implementations. Both versions of the algorithm are shown to be effective in producing good solutions for problems of this type (with appropriately chosen parameters). INFORMS Journal on Computing, ISSN 1091-9856, was published as ORSA Journal on Computing from 1989 to 1995 under ISSN 0899-1499.
Scheduling n Independent Jobs on m Uniform Machines with both Flowtime and Makespan Objectives: A Parametric Analysis
Authors: McCormick S. Thomas , Pinedo Michael L. 
Published: October 2008

We consider the problem of scheduling n jobs without precedence constraints on m uniform machines (i.e., the machines are identical except for speed), with preemptions allowed at no cost. We are interested in generating the entire tradeoff curve of schedules which are Pareto-optimal (undominated) for the flowtime and makespan objectives. To achieve this, we first develop an O(mn) algorithm that produces a schedule with minimum flowtime, subject to a fixed makespan deadline. This algorithm alternates between the Shortest Processing Time on Fastest Machine (SPT-FM) rule and the Longest Remaining Processing Time on Fastest Machine (LRPT-FM) rule. We then investigate how the behavior of the algorithm changes as the deadline is varied parametrically. Our knowledge of the structure of optimal schedules allows us to characterize breakpoints on the (piecewise linear) tradeoff curve, and then to compute all of the O(mn) breakpoints in O(m3n) time. Our analysis yields various useful sensitivity results as a by-product. INFORMS Journal on Computing, ISSN 1091-9856, was published as ORSA Journal on Computing from 1989 to 1995 under ISSN 0899-1499.
Evaluating a New Market: A Forecasting System for Nonimpact Computer Printers
Authors: Oren Shmuel S. , Rothkopf Michael H. , Smallwood Richard D. 
Published: October 2008

In 1975, Xerox put on “hold” and nearly cancelled the development of a high speed xerographic-scanning laser computer printer because prior market research had failed to demonstrate that the company could profitably market such a product. A team composed of Management Scientists, market researchers, and product planners designed and implemented a market-research-based forecasting system for high-speed computer printers. The forecasting system models the behavior of each market research respondent with respect to choice of computer printers. It predicts his choices from among sets of alternatives and his usage levels of the selected products. The system then uses product marketing scenarios to construct a dynamic version of these predictions and produces detailed forecasts of product populations and usage over time. Use of this system produced a credible analysis of the market; based on this analysis, Xerox decided to develop, announce, and manufacture the 9700 Electronic Printing System. The forecasting system was also used to design pricing and other marketing strategies for the new product. The 9700 is now an extremely successful product that is projected to produce billions of dollars of revenue for Xerox. The forecasting system has set a new company standard for evaluating new markets. It is influencing the design of other market-research-based forecasting systems and improving the overall quality of new product planning.
Information Systems in Management Science—Decision Support Systems, Computer Literacy, and Electronic Models
Authors: Vazsonyi Andrew 
Published: October 2008

In the November 1978 issue of Interfaces, the author wrote a column on decision support systems. Much has happened since then and the author shares some of his ideas. Sections presented are: —Seven vignettes related to DSS —What is DSS? —OR/MS methodology: The scientific method —Electronic models —The future.
Microcomputers
Authors: Brennan J. J. , Molloy Michael K. 
Published: October 2008

The precise number of microcomputers marketed and sold to date is unknown. However, since their advent in the mid 1970's, the combined annual sales by all manufacturers is nearing or exceeds one million units. Without question, microcomputers have been widely accepted in a startlingly short period of time because of their low unit cost, low for both systems and software. This does not mean that microcomputers are currently a cost-effective way to replace existing machines, although they may be in some specific situations. Rather, their cost constitutes a low threshold, the point at which owning or using a computer becomes viable for an individual. This threshold is important to both the business and personal user and has changed workstation computation from concept to reality.
On the Establishment of Standards for Comparing Algorithm Performance
Authors: Ignizio James P. 
Published: October 2008

One of the most frustrating tasks encountered by the OR practitioner is that of attempting to select an existing algorithm for application to an immediate real world problem. For purposes of illustration only, consider the OR analyst who is faced with having to solve a large zero-one integer programming problem. Being a member of ORSA, TIMS, SIAM, and other organizations, he realizes that a considerable number of publications have been addressed to this topic and thus he might be able to use one of these to solve the problem at hand. This is sometimes his first mistake. Let us assume that he has surveyed the literature and found “n” publications presenting algorithms which deal directly with his particular problem. At this point in his search he will begin to discover that the mere existence of pertinent algorithms in the literature is not nearly sufficient.
Management Science and Operations Research in the Republic of Korea
Authors: Tcha Dong-wan 
Published: October 2008

The MS/OR movement in South Korea started in the mid '60s when the military made early efforts to utilize MS/OR. These efforts acted as a catalyst to encourage its application in public enterprises. In the mid '70s, large private business followed the public sector's lead by using MS/OR to streamline management practices. By the mid '80s, medium- and small-sized industries began to apply MS/OR techniques, aided by the spread of microcomputers. Recognizing the importance of MS/OR as an efficient management tool for economic development, the government developed educational and training programs in MS/OR in the early '70s. For example, it established KAIST as the leading educational center in science and technology, including MS/OR. As the public interest in MS/OR increased and its role became more important, the Korean Operations Research Society further promoted MS/OR in Korea, playing a leading role in establishing the Association of Asian-Pacific Operational Research Societies. MS/OR has contributed greatly to the rapid economic development in Korea by meeting industry's need for efficient management tools.