bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Random‐Facet simplex algorithm on combinatorial cubes
Authors: Gärtner Bernd 
Published: August 2002

AbstractThe RANDOM‐FACET algorithm is a randomized variant of the simplex method which is known to solve any linear program with n variables and m constraints using an expected number of pivot steps which is subexponential in both n and m. This is the theoretically fastest simplex algorithm known to date if m ≈ n; it provably beats most of the classical deterministic variants which require exp(Ω(n)) pivot steps in the worst case. RANDOM‐FACET has independently been discovered and analyzed ten years ago by Kalai as a variant of the primal simplex method, and by Matous̆ek, Sharir, and Welzl in a dual form. The essential ideas and results connected to RANDOM‐FACET can be presented in a particularly simple and instructive way for the case of linear programs over combinatorial n‐cubes. I derive an explicit upper bound of

on the expected number of pivot steps in this case, using a new technique of “fingerprinting” pivot steps. This bound also holds for generalized linear programs, similar flavors of which have been introduced and studied by several researchers. I then review an interesting class of generalized linear programs, due to Matous̆ek, showing that RANDOM‐FACET may indeed require an expected number of $\exp \bigl(\Omega\bigl(\sqrt n\bigr)\bigr)$ pivot steps in the worst case. The main new result of the paper is a proof that all actual linear programs in Matous̆ek's class are solved by RANDOM‐FACET with an expected polynomial number of $O \bigl(n^2 \bigr)$ pivot steps. This proof exploits a combinatorial property of linear programming which has only recently been discovered by Holt and Klee. The result establishes the first scenario in which an algorithm that works for generalized linear programs “recognizes” proper linear programs. Thus, despite Matous̆ek's worst‐case result, the question remains open whether RANDOM‐FACET (or any other simplex variant) is a polynomial‐time algorithm for linear programming. Finally, I briefly discuss extensions of the combinatorial cube results to the general case. © 2002 Wiley Periodicals, Inc. Random Struct. Alg., 20:353–381, 2002
The degree sequence of a scale‐free random graph process
Authors: Bollobás B´ela , Riordan Oliver , Spencer Joel , Tusnády Gábor 
Published: August 2002

AbstractRecently, Barabási and Albert [2] suggested modeling complex real‐world networks such as the worldwide web as follows: consider a random graph process in which vertices are added to the graph one at a time and joined to a fixed number of earlier vertices, selected with probabilities proportional to their degrees. In [2] and, with Jeong, in [3], Barabási and Albert suggested that after many steps the proportion P(d) of vertices with degree d should obey a power law P(d)αd−γ. They obtained γ=2.9±0.1 by experiment and gave a simple heuristic argument suggesting that γ=3. Here we obtain P(d) asymptotically for all d≤n1/15, where n is the number of vertices, proving as a consequence that γ=3. © 2001 John Wiley & Sons, Inc. Random Struct. Alg., 18, 279–290, 2001
On the chromatic number of set systems
Authors: Kostochka Alexandr , Mubayi Dhruv , Rödl Vojtěch , Tetali Prasad 
Published: August 2002

AbstractAn (r, l)‐system is an r‐uniform hypergraph in which every set of l vertices lies in at most one edge. Let mk(r, l) be the minimum number of edges in an (r, l)‐system that is not k‐colorable. Using probabilistic techniques, we prove that

where br, l is explicitly defined and ar, l is sufficiently small. We also give a different argument proving (for even k)

where a′r, l=(r−l+1)/r(2r−1re)−l/(l−1).Our results complement earlier results of Erdős and Lovász [10] who mainly focused on the case l=2, k fixed, and r large. © 2001 John Wiley & Sons, Inc. Random Struct. Alg., 19: 87–98, 2001
Bathtub dynamics: initial results of a systems thinking inventory
Authors: Sweeney Linda Booth , Sterman John D. 
Published: August 2002

AbstractIn a world of accelerating change, educators, business leaders, environmentalists and scholars are calling for the development of systems thinking to improve our ability to take effective actions. Through courses in the K‐12 grades, universities, business schools, and corporations, advocates seek to teach people to think systemically. These courses range from one‐day workshops with no mathematics to graduate level courses stressing formal modeling. But how do people learn to think systemically? What skills are required? Does a particular type of academic background improve one's ability to think systemically? What systems concepts are most readily understood? Which tend to be most difficult to grasp? We describe initial results from an assessment tool or systems thinking inventory. The inventory consists of brief tasks designed to assess particular systems thinking concepts such as feedback, delays, and stocks and flows. Initial findings indicate that subjects from an elite business school with essentially no prior exposure to system dynamics concepts have a poor level of understanding of stock and flow relationships and time delays. Performance did not vary systematically with prior education, age, national origin, or other demographic variables. We hope the inventory will eventually provide a means for testing the effectiveness of training and decision aids used to improve systems thinking skills. We discuss the implications of these initial results and explore steps for future research. Copyright © 2000 John Wiley & Sons, Ltd.
Adsorption and desorption of benzene on Si(111)‐7 × 7 studied by scanning tunnelling microscopy
Authors: Kawasaki Toyosei , Sakai Daisuke , Kishimoto Hiroshi , Akbar Ade Asneil , Ogawa Takashi , Oshima Chuhei 
Published: August 2002

AbstractThe atomic‐scale processes of benzene adsorption and desorption on an Si(111)‐7 × 7 surface have been investigated with scanning tunnelling microscopy. Analysis of the atomic‐scale images obtained during the adsorption and desorption processes yielded the following results: benzene molecules adsorbed on Si(111)‐7 × 7 with the di‐σ bonds between molecules and two Si atoms, an adatom and a rest atom; and benzene molecules chemisorb and desorb through physisorption states. Copyright © 2001 John Wiley & Sons, Ltd.
Heterogeneity in phase I clinical trials: prior elicitation and computation using the continual reassessment method
Authors: Legedza Anna T. R. , Ibrahim Joseph G. 
Published: August 2002

AbstractHeterogeneity in a phase I clinical trial patient population may lead to distinctly different dose–response relationships along covariate values. For a given target probability of toxicity, this implies different maximum tolerated doses (MTDs) for each distinct subpopulation. Within the framework of O'Quigley, Pepe and Fisher's (1990) continual reassessment method, we propose the notion of average and patient‐specific MTDs by augmenting the dose–response model with other covariates to account for such differences. A method to elicit prior distributions on the dose and other covariate parameters are proposed, based on the predictive approach of Ibrahim and Laud (1994), Laud and Ibrahim (1995), and Ibrahim, Ryan and Chen (1998). This approach relies on prior predictions for the response vector y0 and a quantity a0 specifying uncertainty in y0. Then, y0 and a0 are used to specify a prior for the regression coefficients in a semi‐automatic fashion. The elicitation scheme for y0 uses results from previous phase I cancer clinical trials. The average and patient‐specific MTDs and an elicitation method are demonstrated in logistic regression examples. Copyright © 2001 John Wiley & Sons, Ltd.
Statistical cost‐effectiveness analysis of two treatments based on net health benefits
Authors: Laska Eugene M. , Meisner Morris , Siegel Carole , Wanderling Joseph 
Published: August 2002

AbstractStatistical methods for cost‐effectiveness analysis (CEA) for two treatments that mimic the deterministic optimal rules of CEA are presented. In these rules the objective is to determine the treatment with the maximal effectiveness whose unit cost is less than an amount, λ, that a decision‐maker is willing to pay (WTP). This is accomplished by identifying the treatment with the largest positive net health benefit (NHB), which is a function of λ, while controlling the familywise error rate both when the WTP value is given and when it is unspecified. Fieller's theorem is used to determine a region of WTP values where the NHBs of the treatments are not distinguishable. For each λ outside of the confidence region, the larger treatment is identified. A newly developed one‐tailed analogue of Fieller's theorem is used to determine the WTP values where a treatment's NHB is positive. The situation in which both treatments are experimental is distinguished from the case where one of the treatments is usual care. The one‐tailed confidence region is used in the latter case to obtain the λ values where the NHBs are not different, and determining the region of positivity of the NHBs may be unnecessary. An example is presented in which the cost‐effectiveness of two antipsychotic treatments is evaluated. Copyright © 2001 John Wiley & Sons, Ltd.
The impact of anxiety on the accuracy of diagnostic decision‐making
Authors: Cumming Steven R. , Harris Lynne M. 
Published: August 2002

AbstractThe impact of anxiety on the accuracy of diagnostic decision‐making is a neglected area of research despite its clear implications for the welfare of clients receiving health care. This paper presents the findings of two studies examining the effects of experimentally‐induced performance anxiety (Study 1) and naturally‐occurring state anxiety (Study 2) on the ability of senior radiography students to make simple same–different decisions about simultaneously presented images and to carry out a secondary verbal memory task. In both studies the more anxious group was less accurate in the primary decision‐making task, but there was no decrement in performance on the secondary task. The results are difficult to reconcile with predictions from Eysenck and Calvo's9 processing efficiency account of the impact of anxiety on performance. Rather, the results are consistent with the notion that a primary adaptive purpose of anxiety is to disengage from tasks or stimuli currently occupying attention in order to allow organisms to attend to potential threats. Copyright © 2001 John Wiley & Sons, Ltd.
Strategic groups and competitive enactment: a study of dynamic relationships between mental models and performance
Authors: Osborne J. David , Stubbart Charles I. , Ramaprasad Arkalgud 
Published: August 2002

AbstractThis study used computer‐assisted content analysis of more than four hundred presidents' letters to shareholders to examine empirical linkages between cognitive strategic groups clustered by themes in the reports and strategic groups clustered by performance. We found these groups converged as predicted by the literature, and that mental models and performance are involved in a recursive process of competitive enactment which contributes to strategic group stability. Our research used inductively derived themes from the letters to structure a mental model widely shared in the pharmaceutical industry, and then employed thematic variations to find stable clusters of companies. These thematic clusters were triangulated with the strategic groups from a published study of the same industry, in the same period, and were shown to converge. Additionally, longitudinal linkages between earlier mental models of strategic goals and later reports of performance were found. The findings of our large‐scale empirical study support strategic group theory, demonstrate a novel approach to data mining, and pose questions for future research. Copyright © 2001 John Wiley & Sons, Ltd.
Who directs strategic change? Director experience, the selection of new CEOs, and change in corporate strategy
Authors: Westphal James D. , Fredrickson James W. 
Published: August 2002

AbstractWe develop a theory of board‐directed strategic change in which directors (1) conceive changes in corporate strategy that reflect the strategies of their own home companies, and (2) select new CEOs who have prior experience with similar strategies to facilitate implementation. The findings show that, while the experience of new CEOs appears to predict corporate strategic change, these effects disappear after accounting for board experience. Thus, our results suggest that executive effects on strategy can mask board effects. Copyright © 2001 John Wiley & Sons, Ltd.
Identifying liabilities of foreignness and strategies to minimize their effects: the case of labor lawsuit judgments in the United States
Authors: Mezias John M. 
Published: August 2002

AbstractMost foreign direct investment (FDI) theories assume that foreign subsidiaries are at a disadvantage relative to domestic firms; that is, they suffer a liability of foreignness. Following this reasoning, most FDI research has focused on advantages foreign investors must possess to overcome whatever disadvantages they face. Research directly investigating the sources of foreign subsidiary disadvantages has been notably lacking, despite the fact that understanding disadvantages could uncover ways to reduce exposure to these liabilities of foreignness and improve management of FDI. This study focuses on whether labor lawsuit judgments represent a liability for foreign subsidiaries operating in the United States (U.S.). Specifically, I tested whether 486 British, German, and Japanese subsidiaries operating in the U.S. had more labor lawsuits brought to judgment than a matched sample of U.S.‐owned firms. Results indicate that foreign subsidiaries faced significantly more labor lawsuit judgments in both federal and state jurisdictions. I also investigated several variables hypothesized to be associated with a reduction in labor lawsuit judgments facing foreign subsidiaries. Foreign subsidiaries who used American top officers or whose parent firms had more U.S. operations faced fewer lawsuits, while foreign subsidiaries using human resource professionals actually faced more labor lawsuit judgments. Implications of these findings and avenues for future research are discussed. Copyright © 2002 John Wiley & Sons, Ltd.
Measuring and testing change in strategic management research
Authors: Bergh Donald D. , Fairbank James F. 
Published: August 2002

AbstractThis paper reviews some critical issues associated with measuring and testing change and then reports on how strategy researchers have addressed those matters. We first discuss three key methodological requirements: reliability assumptions of change variables, correlations between the change variable and its initial measure, and selection of unbiased measurement alternatives. Next, we present data from a content analysis of 126 change studies which suggest that strategy researchers tend not to recognize those requirements. Indeed, the typical approach used to measure and test change (as a simple difference between two measures of the same variable) is usually inappropriate and could lead to inaccurate findings and flawed conclusions. We conclude by offering suggestions for how change can be studied more rigorously. Copyright © 2002 John Wiley & Sons, Ltd.
Shimba—an environment for reverse engineering Java software systems
Authors: Systä Tarja , Koskimies Kai , Müller Hausi 
Published: August 2002

AbstractShimba is a reverse engineering environment to support the understanding of Java software systems. Shimba integrates the Rigi and SCED tools to analyze and visualize the static and dynamic aspects of a subject system. The static software artifacts and their dependencies are extracted from Java byte code and viewed as directed graphs using the Rigi reverse engineering environment. The run‐time information is generated by running the target software under a customized SDK debugger. The generated information is viewed as sequence diagrams using the SCED tool. In SCED, statechart diagrams can be synthesized automatically from sequence diagrams, allowing the user to investigate the overall run‐time behavior of objects in the target system.Shimba provides facilities to manage the different diagrams and to trace artifacts and relations across views. In Shimba, SCED sequence diagrams are used to slice the static dependency graphs produced by Rigi. In turn, Rigi graphs are used to guide the generation of SCED sequence diagrams and to raise their level of abstraction. We show how the information exchange among the views enables goal‐driven reverse engineering tasks and aids the overall understanding of the target software system. The FUJABA software system serves as a case study to illustrate and validate the Shimba reverse engineering environment. Copyright © 2001 John Wiley & Sons, Ltd.
‘Devolution’ as an opportunity to test the ‘synergism hypothesis’ and a cybernetic theory of political systems
Authors: Corning Peter A. 
Published: August 2002

Abstract‘Devolution’ is a political buzzword these days as empires, nations, bureaucracies and even business firms collapse, divide, downsize, outsource and in various ways become less than they once were. But what does devolution mean? How can we measure it? And, most important, how do we explain it? Some years ago it was proposed that synergistic functional effects of various kinds have been the underlying causal agency in the progressive evolution of complex, goal‐oriented (teleonomic) systems at all levels of biological organization, including human societies. (The term ‘synergy’ refers to otherwise unattainable combined effects that are produced by the interactions among various elements, parts or individuals.) Support for this theory has continued to mount over the past decade or so, and we will briefly review some of the evidence. One important corollary of this theory is the proposition that all teleonomic systems require cybernetic control processes which, in human societies, are typically referred to as political systems, management systems, or governments. In accordance with the synergism hypothesis, it is postulated that the fate of any cybernetic control process in a living system is ultimately contingent upon the underlying functional effects that the system produces; the functional synergies are the very cause of the differential selection and survival of complex systems and their cybernetic subsystems. Can this theory of government qua social cybernetics be tested? It is argued here that the phenomena often referred to as ‘devolution’ provide just such an opportunity. A causal explanation of socio‐political systems should be able to account not only for various ‘progressive’ trends but also for the many cases in which regression or collapse occurs. Some studies related to political devolution will be discussed, and the arguments for competing hypotheses will be considered. A major example of political devolution will also be invoked in support of this theory. Copyright © 2001 John Wiley & Sons, Ltd.
Recovery of neuromuscular junction morphology following 16 days of spaceflight
Authors: Deschenes Michael R. , Britt Amanda A. , Gomes Ronald R. , Booth Frank W. , Gordon Scott E. 
Published: August 2002

AbstractIt has previously been established that spaceflight elicits alterations in the morphology of the neuromuscular system that includes expansion of the neuromuscular junction (NMJ) and myofiber atrophy. The purpose of this study was to determine the capacity of the neuromuscular system to recover from spaceflight‐induced modifications upon return to normal gravity. Soleus muscles were obtained from rats participating in the 16‐day Neurolab space shuttle mission at 1 day and 14 days after returning to Earth: solei were also taken at the same time points from ground‐based control rats. Cytofluorescent techniques, coupled with confocal microscopy, were used to assess NMJ morphology. Histochemistry, in conjunction with phase contrast microscopy, was employed to examine myofiber size and type. Results indicate that 1 day after landing both pre‐ and postsynaptic stained areas of the NMJ were significantly (P ≤ 0.05) larger in the spaceflight group than in controls. Moreover, significant myofiber atrophy was demonstrated in animals subjected to 0 gravity. By 14 days following return to the Earth, however, NMJ stained areas and muscle fiber size were no longer different from control values at that same interval. These results suggest that the neuromuscular system possesses a robust capacity to recover from spaceflight‐induced perturbations upon return to normal gravitational influences. Synapse 42:177–184, 2001. © 2001 Wiley‐Liss, Inc.
Inhibition of glutamate release by fluspirilene in cerebrocortical nerve terminals (synaptosomes)
Authors: Wang Su‐Jane 
Published: August 2002

AbstractFluspirilene, a neuroleptic drug which is used clinically to treat schizophrenic patients, is a dopamine D2 receptor antagonist. Besides its well‐known actions on the dopamine receptors, fluspirilene also displays calcium channel‐blocking activity. The aim of this study was to investigate the effect of fluspirilene on the 4‐aminopyridine (4AP)‐evoked glutamate release in the cerebrocortical nerve terminals (synaptosomes). Fluspirilene reduced 4AP‐evoked glutamate release in a concentration‐dependent manner. This inhibitory effect was associated with a decrease in the depolarization‐evoked increase in the cytoplasmic free Ca2+ concentration ([Ca2+]C), which could be completely abolished by the Ca2+ channel blocker ω‐CgTX GVIA. Furthermore, fluspirilene did not produce any effect on ionomycin‐evoked glutamate release. These results suggest that fluspirilene inhibits glutamate release primarily by reducing presynaptic Ca2+ influx via N‐type Ca2+ channels in rat cerebrocortical nerve terminals. This finding implies that presynaptic Ca2+ channel blockade concomitant with inhibition of glutamate release and possibly other neurotransmitters release may contribute to the antischizophrenic action of fluspirilene. Synapse 44:36–41, 2002. © 2002 Wiley‐Liss, Inc.
Protection of dopaminergic nigrostriatal afferents by GDNF delivered by microspheres in a rodent model of Parkinson's disease
Authors: Gouhier Christelle , Chalon Sylvie , Aubert‐Pouessel Anne , Venier‐Julienne Marie‐Claire , Jollivet Christophe , Benoit Jean‐Pierre , Guilloteau Denis 
Published: August 2002

AbstractThe use of glial cell line‐derived neurotrophic factor (GDNF) appears to be a promising strategy to promote survival and function of the nigrostriatal dopaminergic pathway damaged in Parkinson's disease (PD). However, effective intracerebral administration is required for optimal therapeutic benefit and tools to evaluate such therapies must be developed. A rodent model of PD was therefore developed using striatal injection of 6‐hydroxydopamine (6‐OHDA) with simultaneous implantation of GDNF‐delivering microspheres. The effects of GDNF released from microspheres were assessed by classical methods such as amphetamine‐induced rotating behavior and tyrosine hydroxylase (TH) immunoreactivity, as well as by quantitative autoradiography using PE2I, a dopamine transporter (DAT) radiotracer, which is also suitable for SPET imaging in humans. 6‐OHDA‐lesioned animals that received microspheres without GDNF were used as controls. During the first 3 weeks after simultaneous lesion and implantation, the amphetamine‐induced rotating behavior of GDNF‐treated rats was improved compared to controls and an increase in TH expression (+26%) was measured in the striatum 6 weeks after lesion. In accordance with these results, an increase in striatal PE2I‐labeled DAT density was obtained (+17%) after 3 and 6 weeks of treatment. In conclusion, this study demonstrates the neuroprotective action of GDNF delivered by microspheres and suggests that PE2I may be an appropriate radiotracer for use in SPET scintigraphy to follow up treatment of PD in humans. Synapse 44:124–131, 2002. © 2002 Wiley‐Liss, Inc.