bluuebunny/crossref_metadata_2025 huggingface dataset:
NONHOMOGENEOUS, NON-LINEAR DEFORMATION OF POLYMER GELS SWOLLEN WITH MAGNETO-RHEOLOGICAL SUSPENSIONS
Authors: SZABÓ DÉNES , ZRÍNYI MIKLÓS
Published: August 2002

Polymer gels swollen with a magneto-rheological suspension are highly elastic materials with considerable magnetic susceptibility. In this work the magnetic field induced deformation and motion of these magnetic polymer systems is discussed. We present a continuum material model by introducing magnetic equations into non-linear elasticity theory. The material properties of these magnetic rubber-like substances are characterized with a Langevin type magnetization and a neo-Hookean strain energy function. The non-linear character of the equations that describe the material properties and the nonhomogeneity of the deformation lead to a unique deformation mechanism. In order to demonstrate the characteristics of the magnetic field induced deformations we present numerical and finite element calculations and compare them with experimental results.
OSCILLATORY CONVECTION IN VISCOELASTIC, FERROMAGNETIC/DIELECTRIC LIQUIDS
Authors: SIDDHESHWAR P. G.
Published: August 2002

Oscillatory convection in viscoelastic ferromagnetic and dielectric liquids of the Rivlin-Ericksen, Maxwell and Oldroyd types is studied analytically by considering free-free, isothermal boundaries with idealized conditions on the magnetic / electric potential. The linear theory reveals the stabilizing nature of the strain retardation parameter and the destabilizing nature of the stress relaxation and magnetization / dielectric parameters. The Maxwell liquids are found to be more unstable than the one subscribing to the Oldroyd description whereas the Rivlin-Ericksen liquid is comparatively more stable. The results have implications in many non-isothermal applications of ferromagnetic and dielectric liquids especially in energy conversion devices.
MULTISCALE ANALYSIS OF ELECTRORHEOLOGICAL FLUIDS
Authors: VERNESCU BOGDAN
Published: August 2002

We construct a microscale model for a rigid particle suspension in a viscous fluid that includes Maxwell electrostatic forces. Via homogenization techniques we characterize the properties the material exhibits at the macroscale. The change in the effective constitutive equations is due to the highly oscillating electrostatic forces. The material properties are determined by both hydrodynamic and electrostatic particle interactions.
Continuum modelling of electrorheological fluids
Authors: DROUOT R. , NAPOLI G. , RACINEUX G.
Published: August 2002

A thermodynamical continuum modelling is proposed for electrorheological fluids. This theormodynamical approach tries to describe the response of an electrorheological fluid in the solid phase (which means with an applied adequate electric field) under mechanical solicitations. Thermodynamic formulations distinguish the contributions due to reversible and irreversible process. In an electrorheological fluid the microstructure generated by the application of an electric field introduces parameters whose the evolution of which influence the behavior. These parameters will be defined as internal variables, or hidden variables, in the formulation of thermodynamics. They are used for the description of dissipative effects. The choice and the number of pertinent parameters are crucial and need to be selected according to the nature of microscopic mechanism and experimental observations. The presence of fibrous structures in the E.R. fluid, when an electric field is applied, is an observed fact. In the theory of thermodynamics with internal variables, the introduction of internal variables doesn't modify, by hypothesis, the balance equations. Nevertheless, the experiments show the existence of hysteresis phenomenon due to the reorganization, at the microscopic level, of the particle that compose the fibers. In order to describe these phenomena, we introduce two internal variables following an idea of Kiryushin.
A TWO-FLUID MODEL FOR ELECTRO- AND MAGNETORHEOLOGICAL SUSPENSIONS
Authors: VON PFEIL KARL , GRAHAM MICHAEL D. , KLINGENBERG DANIEL J. , MORRIS JEFFREY F.
Published: August 2002

A two-fluid continuum model is developed to describe mass transport in electro- and magnetorheological suspensions. The particle flux is related to the field-induced stresses. Solutions of the resulting mass balance show column formation in the absence of flow, and stripe formation when a suspension is subjected simultaneously to an applied electric field and shear flow.
ER-FLUID RHEOLOGICAL PROPERTIES IN TERMS OF THE MULTIPARTICLE MODEL OF A COMPOSITE
Authors: YANOVSKY YU. G. , ZGAEVSKII V. E. , SHULMAN Z. P. , KOROBKO E. V.
Published: August 2002

The three-dimensional multi-particle well-ordered model could be considered as an analogy to a crystal body. We use this model for describing rheological properties of concentrated electrorheological fluids (ER fluids). According to this model, the particles of the suspension take their places at sites of a grid with specified type of symmetry and then an electric field is applied to the fluid. Taking into account hydrodynamic couple interaction of particles and forces of electrostatic interaction of particles polarized under the action of an external electric field and employing the mathematical apparatus of the microscopic theory of crystals, we construct the basic relationships for describing viscoelastic electrorheological properties of ER fluids.
STRESS BEHAVIOR AND CONDUCTIVITY OF THE ELECTRO- RHEOLOGICAL SUSPENSIONS
Authors: TANAKA KATSUFUMI , ICHIZAWA KENSUKE , ONISHI YOHEI , KUBONO ATSUSHI , AKIYAMA RYUICHI
Published: August 2002

The steady stress under static electric fields and the conduction current passing through the electro-rheological (ER) suspensions with cation exchange resin particles were investigated simultaneously as a function of the shear rate. The shear thinning behavior was found for a suspension with a higher viscosity of the continuous phase. Further, a remarkable dip behavior was found for a dilute ER suspension. The apparent conductivity, which was calculated from the conduction current, probed sensitively the corresponding behavior to the stress responses.
DETERMINATION OF RHEOLOGICAL AND MAGNETIC PROPERTIES FOR MAGNETORHEOLOGICAL COMPOSITES VIA SHEAR MAGNETIZATION MEASUREMENTS
Authors: HORVATH A. T. , KLINGENBERG D. J. , SHKEL Y. M.
Published: August 2002

Anisotropic solid-state magnetorheological (MR) composites are prepared by applying magnetic fields to isotropic suspensions in polymer melts and preserved by cross-linking the melts. The composities are studied through a continuum-level perspective at various magnetic field strengths under oscillatory shear. The minimum number of constraints are applied in the derivation of the magnetic and rheological invariants, which relate the measured macroscopic magnetostriction coefficients to the discrete parameters of any microscopic model. The field-induced stress is defined by magnetostriction coefficients, which are material parameters that describe the strain dependence of the magnetization tensor. A comparison of the independently measured rheological and magnetic properties allow for the determination of the magnetostriction coefficients.
EVOLUTION OF CHAIN STRUCTURE OF ELECTRORHEOLOGICAL FLUIDS IN FLOW MODEL
Authors: ZHAO X. P. , GAO X. Y. , GAO D. J.
Published: August 2002

The movement of particles in electrorheological (ER) fluids is analyzed by means of molecular dynamic simulations. We found that the velocity profile of particles can be divided into two zones. One zone near electrodes where particles' velocity profiles change periodically like "breathing type" is called transition zone. The other in the middle of two electrodes where particles move smoothly like a plug is called "plug zone". In addition, the relationship between volume flow rate and relative pressure gradient is simulated out. Factors such as volume flow rate, critical electric field, critical pressure gradient and response time of shutting up were also analyzed respectively.
PHYSICAL MODELING OF DAMPING CHARACTERISTICS OF MR FLUIDS
Authors: SARRAZIN JEROME , CLARACQ JEROME , MONTFORT JEAN-PIERRE
Published: August 2002

The behavior of MR fluids involved in industrial devices is often modeled by analogical models which do no link the parameters with the physical properties of the fluid. From the equations of fluid mechanics, we give a physical meaning to parameters such as friction, elastic and mass coefficients used in the mentioned models. The predictions are checked with experimental data which mimic the behavior of devices such as antiseismic systems. The viscoelastic behavior of MR fluids is characterized by mechanical spectroscopy. The complex shear modulus G *(ω) contains all the information about the restoring and viscous forces. For example, the relation between elastic modulus, yield stress and magnetic force is discussed in terms of strain amplitude.
KINETICS OF ELECTRORHEOLOGICAL FLUID SPREADING OVER A HORIZONTAL SURFACE
Authors: BAYKOV V. I. , KOROBKO E. V.
Published: August 2002

A Physical and Mathematical model of the process of fluid drop spreading is suggested which quantitatively describes all the stages of spreading kinetics on the basic of a unified approach. It has been established that gravitational forces exert a pronounced influence on the process of fluid drop spreading over a horizontal solid surface.
TEMPERATURE DEPENDENCE OF MR FLUIDS
Authors: LI W. H. , CHEN G. , YEO S. H. , DU H.
Published: August 2002

The rheological properties of MR fluids, MRF-132LD, are investigated under the steady shear and oscillatory shear for a range of operating temperatures from 20°C to 60°C. This was accomplished by using an advanced rheometer with the parallel-plate configuration. Under the steady shear, the Herschel–Bulkley model is used to model the rheology of the MR fluid. The corresponding parameters namely, τyd, K and n were determined at various temperatures, in an attempt to minimize the discrepancies between the experimental results and that predicted by the model. The results show that τyd, K and n all show decreasing trend with temperature. The results suggest that the MR fluid get "thinner" with increasing temperatures. Under the oscillatory shear, viscoelastic properties of the MR fluid were studied in the frequency sweep mode. The storage modulus, G′, decreases with increasing temperatures in both the linear viscoelastic region and the nonlinear viscoelastic region. In addition, two critical frequencies, ωcr and ωm, were identified in the latter region. They were found to decrease with increasing temperatures. Finally, thermodynamics are used to explain temperature dependence of MR properties.
A SINGLE-CHAIN MODEL FOR QUASI-STATIC SHEAR STRESS-STRAIN PROPERTIES OF MAGNETORHEOLOGICAL FLUIDS
Authors: JIANG ZEHUI , LU KUNQUAN
Published: August 2002

The quasi-static shear stress-strain property of magnetorheological fluids is analyzed, based on the calculation of the interaction energy of chain of equi-spaced magnetic spheres with the applied uniform magnetic field. First, the dipole moment of a chain of equi-spaced magnetic spheres imposed to a uniform magnetic field is determined, and simple expressions are given. Then, the interaction energy of a chain with the forcing field is determined, and the restoring force is calculated when the chain is slanted and elongated. In our analysis, only the contributions from the mutual interaction of the particles in chains are considered. Comparison with experimental results is made, and good agreement is obtained.
SURFACE SHEAR STRESS ENHANCEMENT UNDER MR FLUID DEFORMATION
Authors: GORODKIN S. , ZHURAVSKI N. , KORDONSKI W.
Published: August 2002

The effect of a regular surface micro topography on a magnitude of surface shear stress in a normal magnetic field under MR fluid deformation between two magnetic plates has been experimentally investigated. It was revealed that the static yield stress was increased by a factor of 2.8 for radially grooved plates as against smooth ones. The effect was most conspicuous at small iron particles volume fractions and strong magnetic fields. It is assumed that grooves create a magneto mechanical barrier that prevents the slip of particle aggregates against the wall.
MAGNETORHEOLOGY OF A MILLIMETRIC STEEL SPHERES SUSPENSION
Authors: BOSSIS G. , VOLKOVA O. , LACIS S. , GUYOT M.
Published: August 2002

The magnetorheology of a "suspension" of millimetric-size steel spheres in oil has been studied. After a precise measurement of the magnetic properties of the particles we show that the yield stress is well characterized and that it can be predicted by a finite element method and a non-affine model where the chains break in the middle. Some experiments in microgravity confirm that the sedimentation does not alter our results and also shows that the magnetic stress decreases with the shear rate.
ONLINE ROUTING IN CONVEX SUBDIVISIONS
Authors: BOSE PROSENJIT , BRODNIK ANDREJ , CARLSSON SVANTE , DEMAINE ERIK D. , FLEISCHER RUDOLF , LÓPEZ-ORTIZ ALEJANDRO , MORIN PAT , IAN MUNRO J.
Published: August 2002

We consider online routing algorithms for finding paths between the vertices of plane graphs. We show (1) there exists a routing algorithm for arbitrary triangulations that has no memory and uses no randomization, (2) no equivalent result is possible for convex subdivisions, (3) there is no competitive online routing algorithm under the Euclidean distance metric in arbitrary triangulations, and (4) there is no competitive online routing algorithm under the link distance metric even when the input graph is restricted to be a Delaunay, greedy, or minimum-weight triangulation.
AN IMPROVED ALGORITHM FOR SUBDIVISION TRAVERSAL WITHOUT EXTRA STORAGE
Authors: BOSE PROSENJIT , MORIN PAT
Published: August 2002

We describe an algorithm for enumerating all vertices, edges and faces of a planar subdivision stored in any of the usual pointer-based representations, while using only a constant amount of memory beyond that required to store the subdivision. The algorithm is a refinement of a method introduced by de Berg et al (1997), that reduces the worst case running time from O(n2) to O(n log n). We also give experimental results that show that our modified algorithm runs faster not only in the worst case, but also in many realistic cases.
OPTIMAL POLYGON COVER PROBLEMS AND APPLICATIONS
Authors: CHEN DANNY Z. , HU XIAOBO S. , WU XIAODONG
Published: August 2002

Polygon cover problems are important in several applied areas, such as material layout, layered manufacturing, radiation therapy and radiosurgery, etc. In this paper, we study three optimal polygon cover problems: monotone polygon cover among obstacles, star-shaped polygon cover among obstacles, and strip cover for trapezoidalized polygons. Based on some interesting geometric observations, we develop efficient algorithms for solving these problems. The complexity bounds of our monotone cover and star-shaped cover algorithms are comparable to those of the previously best known algorithms for simpler cases of the problems without considering obstacles. Our strip cover algorithm improves the quality of the previously best known solutions.
A GENERALIZATION OF {\RM GO{\L}\c{A}B'S} THEOREM AND APPLICATIONS TO FRACTURE MECHANICS
Authors: GIACOMINI ALESSANDRO
Published: August 2002

We study the lower semicontinuity for functionals of the form K → ∫K φ (x, ν)dℋ1 defined on compact sets in ℝ2 with a finite number of connected components and finite ℋ1 measure and apply the result to the study of quasi-static growth of brittle fractures in linearly elastic inhomogeneous and anisotropic bodies.
OPTIMAL LASER CONTROL OF MOLECULAR SYSTEMS: METHODOLOGY AND RESULTS
Authors: AUGER A. , BEN HAJ YEDDER A. , CANCES E. , LE BRIS C. , DION C. M. , KELLER A. , ATABEK O.
Published: August 2002

We report on some mathematical and numerical work related to the control of the evolution of molecular systems using laser fields. More precisely, the control of the orientation of molecules is our goal. We treat this as an optimal control problem and optimize the laser field to be used experimentally by using both deterministic and stochastic algorithms. Comparisons between the different strategies are drawn. In particular, when gradients of the cost functional are used, the different ways for their computation are compared and analyzed.
HIGHER ORDER LINKING NUMBERS, CURVATURE AND HOLONOMY
Authors: PENNA VITTORIO , SPERA MAURO
Published: August 2002

A differential geometric approach to Milnor-Massey higher order linking numbers for generic links is devised, via Chen's theory of iterated path integrals. Massey linking numbers arise from curvature forms of nilpotent "topological" connections, determined by the link structure, and interpreted in terms of intersection theory, leading to a fairly easy computation thereof. A version of the Turaev-Porter theorem expressing equality of Milnor and Massey linking numbers is also exhibited along the same lines, by computing suitable flat connection parallel transport operators in two different ways.
UNUSUAL FORMULAE FOR THE EULER CHARACTERISTIC
Authors: ROBERTS JUSTIN
Published: August 2002

Everyone knows that the Euler characteristic of a combinatorial manifold is given by the alternating sum of its numbers of simplices. It is shown that there are other linear combinations of the numbers of simplices which are combinatorial invariants, but that all such invariants are multiples of the Euler characteristic.
TUNNEL NUMBER ONE KNOTS HAVE PALINDROME PRESENTATIONS
Authors: HILDEN HUGH M. , TEJADA DEBORA M. , TORO MARGARITA M.
Published: August 2002

We show that any tunnel number one knot group has a two generator one relator presentation in which the relator is a palindrome in the generators. We use this fact to compute the character variety for this knot groups and we show that it is an affine algebraic set [Formula: see text].
HIGHER SKEIN MODULES
Authors: ANDERSEN JØRGEN ELLEGAARD , TURAEV VLADIMIR
Published: August 2002

We introduce higher skein modules of links generalizing the Conway skein module. We show that these modules are closely connected to the HOMFLY polynomial.
ESSENTIAL ARCBODY AND TANGLE DECOMPOSITIONS OF KNOTS AND LINKS
Authors: VALDEZ-SÁNCHEZ LUIS G.
Published: August 2002

We prove that if K⊂ S3 is either: (I) a link with an essential n-string arcbody decomposition, where at least one arcspace has incompressible boundary, or a knot with an essential n-string tangle decomposition, where (II) each tangle has no parallel strings, or (III) one tangle space is not a handlebody and K is not cabled, then any nontrivial surgery on every component of K produces irreducible manifolds in all cases (with some exceptional surgeries in case (I)) and, in particular, Haken manifolds in cases (I) and (III). Moreover, if K is hyperbolic in (III) and at least one tangle space has incompressible boundary, then all nontrivial surgeries on K are also hyperbolic; this last result is also established for type (I) decompositions under some constraints.
Toward Asian Pacific Financial Centers: A Comparative Study of Financial Developments in Taiwan, Hong Kong and Singapore
Authors: Young Hsiao-Wen , Hung Ken , Cheng David C.
Published: August 2002

There are many societal similarities among Taiwan, Hong Kong and Singapore. However, with respect to financial developments, there is no denying that Hong Kong and Singapore score higher than Taiwan with regard to liberalization and internationalization. The financial developments of the three regions are compared retrospectively and prospectively along the lines of financial institutions, financial markets and government controls. The differences in the relative scales of the three regions' financial industries are highlighted together with a comparison of their developmental processes.
Financial Development and Economic Growth of Developed versus Asian Developing Countries: A Pooling Time-Series and Cross-Country Analysis
Authors: Tsai Shiao-Lin , Wu Chunchi
Published: August 2002

This paper examines the relationship between financial market development and economic growth. By pooling the data of both developed and developing countries, we test the relation between the real GDP growth rate and financial development variables suggested by the aggregate capital endogenous growth model. We find that the capital absorption and saving rates have a significant positive relation with economic growth whereas the interest rate has a negative relation. Since the behavior of these explanatory variables reflects financial development, our results suggest that financial intermediation plays a significant role in economic growth. Furthermore, we find that there was a shift in the economic performance of Asian developing economies in the 1980s. Financial reforms in this region have resulted in a transitory adverse impact on the capital absorption rate. It also appears that economic growth has slowed down recently for most of these newly industrialized economies. Our result suggests that the lack of efficient financial markets may have hindered the economic performance of these economies.
Helping to Prevent Banking Crises: Taking the "State" Out of State Banks
Authors: Kaufman George G.
Published: August 2002

The banking crises experienced in many countries worldwide in recent years can often be attributed, at least in part, to state owned or controlled banks. These banks are often not typically banks in the traditional sense, but are effectively arms of the government to direct credit to favored borrowers in pursuit of economic, political, or social objectives. This frequently results in costly misallocation of resources. In addition, because their bottom line is not necessarily profitability, many consistently generate losses and continue to operate while economically insolvent. They can do this because all of their deposit liabilities are perceived to be fully guaranteed. Thus, their negative net worths are effectively off-budget liabilities of the government. At some point, taxpayers become reluctant to bear this increasing burden and the government is forced to recapitalize their institutions explicitly. To avoid repetitions of these costly policies, state owned banks should be completely privatized.
Emerging Markets: A Disaggregated Perspective on the Gains from Investing Internationally
Authors: Fifield S. G. M. , Lonie A. A. , Power D. M. , Sinclair C. D.
Published: August 2002

Using weekly disaggregated returns data for the top twenty shares, by market value, from seventeen emerging markets over the period 1991–1996, this paper investigates the potential gains from international diversification into these markets. The paper also assesses whether these gains could have been achieved on an ex-ante basis. Finally, the paper quantifies the importance of country and industry factors in emerging market stock returns. The findings suggest that (i) substantial benefits exist from investing in emerging stock markets and (ii) these gains accrue more from the geographical spread than from the industrial mix of the equities included in the portfolio.
Share Return Seasonalities and Price Linkages of Chinese A and B Shares
Authors: Heaney Richard A. , Powell John G. , Shi Jing
Published: August 2002

This paper investigates share price linkages between Chinese corporations' foreign-designated B shares and the numerically dominant domestic A shares of the same companies. Chinese share return seasonalities are examined and the suggested satellite trading relationships are subsequently tested in order to provide an understanding of the linkages between A and B shares. The seasonality results along with arbitrage activity in the market for Chinese A and B shares suggest that a dominant-satellite relationship is likely to exist whereby the A share market is the dominant market for price formation and the B share market is the satellite. The paper identifies significant price linkages from the A to B share markets which are nevertheless weaker in an economic sense than might be expected.
The Underpricing of Initial Public Offerings in the Philippines from 1987 to 1997
Authors: Sullivan Michael J. , Unite Angelo A.
Published: August 2002

In this paper we report returns for initial public offerings (IPOs) in the Philippines and investigate some characteristics found in other countries to affect returns, specifically offer size, firm age, and industry grouping. For a sample of 104 IPOs during the 11-year period 1987 through 1997, we find average initial returns of 22.69 percent. We do not find that offer size, firm age, or industry groupings affect IPO underpricing and conclude from our findings that underwriters who price Philippine IPOs face different regulatory policies, contractual mechanisms, market conditions than those present in other markets.
An Application of Variance-Ratio Test of Five Asian Stock Markets
Authors: Alam M. Imam , Hasan Tanweer , Kadapakkam Palani-Rajan
Published: August 2002

In the present study the variance-ratio test developed by Lo and MacKinlay (1988, and 1989) is applied to monthly stock index returns of five Asian markets that are in different stages of development. The markets examined are Bangladesh, Hong Kong, Malaysia, Sri Lanka and Taiwan. Although previous studies have examined the efficiency issues of the markets in Hong Kong, Malaysia, Sri Lanka and Taiwan, the empirical evidence is often contradictory. The current study looks at the efficiency issues of these markets over a sufficiently long period of time (November 1986 — December 1995) using more appropriate methodology and type of data. Also, this study is the first to provide new evidence on an emerging market in Asia — Bangladesh. Results reported in this study indicate that the index return series of all the sample markets except Sri Lanka do follow a random walk.
Bank Reserve's Setting for Minimizing the Price Fluctuations: Taiwan's Case Studies
Authors: Kuo Chau-Jung
Published: August 2002

This paper presents a stochastic financial model from which one can derive the optimal reserves ratio for stabilizing price level. It is shown that the optimal reserves ratio is a function of the structure of unanticipated shocks to liquid asset market and high-powered money market. An important policy implication, drawn from my model, suggests that it may help for the stabilization of price level if a lower level of the reserve requirements was adopted by the central bank when the shock exists solely in liquid asset market. An application of the presented model to the financial assets in Taiwan suggests that the optimal reserves ratio for stabilizing price level is approximately 5.7717 per cent in the case of the 2-SLS estimation, and 4.2442 per cent in the case of the SUR estimation, below the weighted average of actual 7.7575 per cent up to the end of 1997. The empirical findings further suggest Taiwan's monetary authority would thus have to accept a lower level of the reserve requirements in order to reduce the price fluctuations.
Price Discovery in the Taipei Residential Real Estate Market
Authors: Lu Chiuling , So Raymond W.
Published: August 2002

The price discovery process of the Taipei residential real estate market is examined. Using data from the Ta-An District of Taipei City, empirical evidence indicates that there exists a causal relationship between rental rates and property prices. Results here suggest that the two real estate markets are linked together; hence investors and end users can use price information in one market to predict future movements of the other market.
Some Further Thoughts on MBA Education in Taiwan: How to Choose a Thesis Topic
Authors: Yen Gili
Published: August 2002

The choice of a thesis topic is the first yet also the most important step in writing a master's thesis. The present paper therefore addresses two interrelated aspects involved in choosing a thesis topic: First, it is argued that empirical topics should be given priority over theoretical ones. Among them, refutational empirical studies with their associative differentiating power are preferred to confirmational empirical studies. The paper then moves on to discuss steps that may help students come up with a well-defined thesis topic, and the properties that distinguish a good topic from a less desirable one.
APPLICATIONS OF GAME THEORY TO ECONOMIC EQUILIBRIUM
Authors: OWEN GUILLERMO
Published: August 2002

One of the original expectations for the theory of cooperative games was that it would give us results valid for thin markets (where the number of traders is too small for an equilibrium to be reached). Over a period of years, however, it has been shown that, for market games, both the core and the Shapley values converge, in some sense, to the competitive equilibrium. Thus, the feeling arises that for large market games, the game-theoretic concepts yield nothing other than the equilibrium. In this article, we study the question of convergence of the Shapley value to the equilibrium and show that in some cases the convergence can be extremely slow. A very simple example (the "shoe" game) suggests that replacing the value by the equilibrium is in some sense akin to replacing a random variable by its mean.
MARKOV STRATEGIES ARE BETTER THAN STATIONARY STRATEGIES
Authors: FLESCH J. , THUIJSMAN F. , VRIEZE O. J.
Published: August 2002

We examine the use of stationary and Markov strategies in zero-sum stochastic games with finite state and action spaces. It is natural to evaluate a strategy for the maximising player, player 1, by the highest reward guaranteed to him against any strategy of the opponent. The highest rewards guaranteed by stationary strategies or by Markov strategies are called the stationary utility or the Markov utility, respectively. Since all stationary strategies are Markov strategies, the Markov utility is always larger or equal to the stationary utility. However, in all presently known subclasses of stochastic games, these utilities turn out to be equal. In this paper, we provide a colourful example in which the Markov utility is strictly larger than the stationary utility and we present several conditions under which the utilities are equal. We also show that each stochastic game has at least one initial state for which the two utilities are equal. Several examples clarify these issues.
THE EGALITARIAN NON-k-AVERAGED CONTRIBUTION (ENkAC-) VALUE FOR TU-GAMES
Authors: NAMEKATA TSUNEYUKI , DRIESSEN THEO S. H.
Published: August 2002

This paper deals in a unified way with the solution concepts for transferable utility games known as the Centre of the Imputation Set value (CIS-value), the Egalitarian Non-Pairwise-Averaged Contribution value (ENPAC-value) and the Egalitarian Non-Separable Contribution value (ENSC-value). These solutions are regarded as the egalitarian division of the surplus of the overall profits after each participant is conceded to get his individual contribution specified in a respective manner. We offer two interesting individual contributions (lower- and upper-k-averaged contribution) based on coalitions of size k(k ∈ {1,…,n-1}) and introduce a new solution concept called the Egalitarian Non-k-Averaged Contribution value ( EN k AC -value). CIS-, ENPAC- and ENSC-value are the same as EN 1 AC -, EN n-2 AC - and EN n-1 AC -value respectively. It turns out that the lower- and the upper-k-averaged contribution form a lower- and an upper-bound of the Core respectively. The Shapley value is the centre of gravity of n-1 points; EN 1 AC -,…, EN n-1 AC -value. EN k AC -value of the dual game is equal to EN n-k AC -value of the original game. We provide a sufficient condition on the transferable utility game to guarantee that the EN k AC -value coincides with the well-known solution called prenucleolus. The condition requires that the largest excesses at the EN k AC -value are attained at the k-person coalitions, whereas the excesses of k-person coalitions at the EN k AC -value do not differ.
STRONGLY CONSISTENT SOLUTIONS TO BALANCED TU GAMES
Authors: YANOVSKAYA ELENA
Published: August 2002

Consistency properties of game solutions connect between themselves the solution sets of games with different sets of players. In the paper, the strongly consistent solutions with respect to the Davis–Maschler definition of the reduced games to the class of balanced cooperative TU games with finite sets of players are considered. A cooperative game solution σ to a class [Formula: see text] of a TU cooperative game is called strongly consistent if for any [Formula: see text] and [Formula: see text] , where [Formula: see text] is the reduced game of Γ on the player set S and with respect to x. Evidently, all consistent single-valued solutions are strongly consistent. In the paper, we characterise anonymous, covariant bounded and strongly consistent to the class [Formula: see text] of balanced games. The core, its relative interior and the prenucleolus are among them. However, they are not unique solutions satisfying these axioms. Thus, more axioms are necessary in order to characterise these solutions with strong consistency. One of such axioms is the definition of a solution for the class of balanced two-person games. It is sufficient for the axiomatisation of the prenucleolus without the single-valuedness axiom. If we add the closed graph property of the solution correspondence to the given axioms, then the system characterises only the core. The two axiomatisations are the main result of the paper. An example of a strongly consistent solution different from the prenucleolus, the core and its relative interior is given.
Heterozygous Cellular Glutathione Peroxidase Deficiency in the Mouse
Authors: Forgione Marc A. , Cap Andre , Liao Ronglih , Moldovan Nicanor I. , Eberhardt Robert T. , Lim Chee Chew , Jones John , Goldschmidt-Clermont Pascal J. , Loscalzo Joseph
Published: August 2002

Background—

Oxidant stress has been implicated in the pathogenesis of atherothrombosis and other vascular disorders accompanied by endothelial dysfunction. Glutathione peroxidases (GPx) play an important role in the cellular defense against oxidant stress by utilizing glutathione (GSH) to reduce lipid hydroperoxides and hydrogen peroxide to their corresponding alcohols. Cellular GPx (GPx-1) is the principal intracellular isoform of GPx. We hypothesized that GPx-1 deficiency per se induces endothelial dysfunction and structural vascular abnormalities through increased oxidant stress.

Methods and Results—

A murine model of heterozygous deficiency of GPx-1 (GPx
+/−)
was investigated to examine this hypothesis. Mesenteric arterioles in GPx-1
+/−
mice demonstrated vasoconstriction to acetylcholine compared with vasodilation in wild-type mice (maximal change in vessel diameter, −13.0±2.8% versus 13.2±2.8%,
P
<0.0001). We also noted an increase in the plasma and aortic levels of the isoprostane iPF
2α
-III, a marker of oxidant stress, in GPx-1
+/−
mice compared with wild-type mice (170.4±23 pg/mL plasma versus 98.7±7.1 pg/mL plasma,
P
<0.03; 11.7±0.87 pg/mg aortic tissue versus 8.2±0.55 pg/mg aortic tissue,
P
<0.01). Histological sections from the coronary vasculature of GPx-1
+/−
mice show increased perivascular matrix deposition, an increase in the number of adventitial fibroblasts, and intimal thickening. These structural abnormalities in the myocardial vasculature were accompanied by diastolic dysfunction after ischemia-reperfusion.

Conclusions—

These findings demonstrate that heterozygous deficiency of GPx-1 leads to endothelial dysfunction, possibly associated with increased oxidant stress, and to significant structural vascular and cardiac abnormalities. These data illustrate the importance of this key antioxidant enzyme in functional and structural responses of the mammalian cardiovascular system.
Association of
Chlamydia pneumoniae
With Coronary Artery Disease and Its Progression Is Dependent on the Modifying Effect of Mannose-Binding Lectin
Authors: Rugonfalvi-Kiss Szabolcs , Endrész Valéria , Madsen Hans O. , Burián Katalin , Duba Jenô , Prohászka Zoltán , Karádi István , Romics László , Gönczöl Éva , Füst George , Garred Peter
Published: August 2002

Background—

The possible association between coronary artery disease (CAD) and
Chlamydia pneumoniae (C pneumoniae)
infection is controversial. On the basis of the recent suggestion that mannose-binding lectin (MBL) variant alleles are related to an increased risk of severe atherosclerosis, and on the in vitro interaction of MBL with
C pneumoniae
, we asked whether MBL might contribute to CAD in conjunction with
C pneumoniae
.

Methods and Results—

Antibodies to
C pneumoniae
were measured by immunofluorescence and MBL alleles were determined by polymerase chain reaction technique in samples from 210 patients with CAD and 257 healthy subjects from Hungary collected between 1995 and 1996. A higher percentage of patients with CAD were anti-
C pneumoniae
positive as compared with the control group (
P
=0.058). However, at logistic regression analysis adjusted to age, sex, and serum lipid levels, this difference was confined only to subjects carrying MBL variant alleles (
P
=0.035, odds ratio 2.63, [95% CI: 1.07 to 6.45]). In contrast, no significant difference was seen in those homozygous for the normal MBL allele (
P
=0.412). During a 65±5.8-month follow-up period, major outcomes (new myocardial infarction, and/or bypass operation or cardiovascular death) occurred in 11
C pneumoniae
positive and 3
C pneumoniae
negative patients. In the
C pneumoniae
positive group, the odds ratio of development of outcomes was 3.27 (95% CI: 1.10 to 9.71,
P
=0.033) in the carriers of the MBL variant alleles compared with the homozygous carriers of the normal MBL allele.

Conclusions—

These results indicate that infection with
C pneumoniae
leads mainly to the development and progression of severe CAD in patients with variation in the MBL gene.
Influence of Lipid-Lowering Therapy on the Progression of Coronary Artery Calcification
Authors: Achenbach Stephan , Ropers Dieter , Pohle Karsten , Leber Alexander , Thilo Christian , Knez Andreas , Menendez Theresa , Maeffert Ralph , Kusus Magda , Regenfus Matthias , Bickel Andrea , Haberl Ralph , Steinbeck Gerhard , Moshage Werner , Daniel Werner G.
Published: August 2002

Background—

Coronary calcification measured by fast computed tomography techniques is a surrogate marker of coronary atherosclerotic plaque burden. In a cohort study, we prospectively investigated whether lipid-lowering therapy with a cholesterol synthesis enzyme inhibitor reduces the progression of coronary calcification.

Methods and Results—

In 66 patients with coronary calcifications in electron beam tomography (EBT), LDL cholesterol >130 mg/dL, and no lipid-lowering treatment, the EBT scan was repeated after a mean interval of 14 months and treatment with cerivastatin was initiated (0.3 mg/d). After 12 months of treatment, a third EBT scan was performed. Coronary calcifications were quantified using a volumetric score. Cerivastatin therapy lowered the mean LDL cholesterol level from 164±30 to 107±21 mg/dL. The median calcified volume was 155 mm
3
(range, 15 to 1849) at baseline, 201 mm
3
(19 to 2486) after 14 months without treatment, and 203 mm
3
(15 to 2569) after 12 months of cerivastatin treatment. The median annualized absolute increase in coronary calcium was 25 mm
3
during the untreated versus 11 mm
3
during the treatment period (
P
=0.01). The median annual relative increase in coronary calcium was 25% during the untreated versus 8.8% during the treatment period (
P
<0.0001). In 32 patients with an LDL cholesterol level <100 mg/dL under treatment, the median relative change was 27% during the untreated versus −3.4% during the treatment period (
P
=0.0001).

Conclusions—

Treatment with the cholesterol synthesis enzyme inhibitor cerivastatin significantly reduces coronary calcium progression in patients with LDL cholesterol >130 mg/dL.
Impact of Community-Wide Police Car Deployment of Automated External Defibrillators on Survival From Out-of-Hospital Cardiac Arrest
Authors: Myerburg Robert J. , Fenster Jeffrey , Velez Mauricio , Rosenberg Donald , Lai Shenghan , Kurlansky Paul , Newton Starbuck , Knox Melenda , Castellanos Agustin
Published: August 2002

Background—

Disappointing survival rates from out-of-hospital cardiac arrests encourage strategies for faster defibrillation, such as use of automated external defibrillators (AEDs) by nonconventional responders.

Methods and Results—

AEDs were provided to all Miami-Dade County, Florida, police. AED-equipped police (P-AED) and conventional emergency medical rescue (EMS) responders are simultaneously deployed to possible cardiac arrests. Times from 9-1-1 contact to the scene were compared for P-AED and concurrently deployed EMS, and both were compared with historical EMS experience. Survival with P-AED was compared with outcomes when EMS was the sole responder. Among 420 paired dispatches of P-AED and EMS, the mean±SD P-AED time from 9-1-1 call to arrival at the scene was 6.16±4.27 minutes, compared with 7.56±3.60 minutes for EMS (
P
<0.001). Police arrived first to 56% of the calls. The time to first responder arrival among P-AED and EMS was 4.88±2.88 minutes (
P
<0.001), compared with a historical response time of 7.64±3.66 minutes when EMS was the sole responder. A 17.2% survival rate was observed for victims with ventricular fibrillation or pulseless ventricular tachycardia (VT/VF), compared with 9.0% for standard EMS before P-AED implementation (
P
=0.047). However, VT/VF benefit was diluted by the observation that 61% of the initial rhythms were nonshockable, reducing the absolute survival benefit among the total study population to 1.6% (P-AED, 7.6%; EMS, 6.0%).

Conclusions—

P-AED establishes a layer of responders that generate improved response times and survival from VT/VF. There was no benefit for victims with nonshockable rhythms.
Ursodeoxycholic acid for the prevention of hepatic complications in allogeneic stem cell transplantation
Authors: Ruutu Tapani , Eriksson Britta , Remes Kari , Juvonen Eeva , Volin Liisa , Remberger Mats , Parkkali Terttu , Hägglund Hans , Ringdén Olle
Published: August 2002

The role of ursodeoxycholic acid (UDCA) in the prevention of hepatic complications after allogeneic stem cell transplantation was studied in a prospective randomized open-label multicenter trial. A total of 242 patients were allocated to receive (n = 123) or not to receive (n = 119) UDCA in the dose of 12 mg/kg/d orally from the day preceding the conditioning until day 90 after transplantation. In the UDCA-treated group a significantly smaller proportion of patients developed a serum bilirubin level exceeding 50 μM (18 of 123 versus 31 of 119, P = .04), and similarly a smaller proportion of patients exceeded the alanine aminotransferase level of 100 U/L. There was no difference in the incidence of veno-occlusive disease of the liver. Compared to the control group, in the UDCA-treated group there was a nonsignificant trend toward a lower overall incidence of acute graft-versus-host disease (GVHD) and a significantly lower incidence of grade III to IV acute GVHD (5 of 123 versus 17 of 119,P = .01), stage II to IV liver and intestinal GVHD, and stage III to IV skin GVHD. There was no difference in the incidence of chronic GVHD or in the relapse rate. Among the patients given UDCA, the survival at 1 year was significantly better, 71% versus 55% (P = .02), and the nonrelapse mortality rate was lower, 19% versus 34% (P = .01), than in the control group. There were significantly more deaths in GVHD in the control group. In conclusion, UDCA administration reduced hepatic problems and severe acute GVHD and improved survival. These results suggest a role for UDCA in the prevention of transplant-related complications in allogeneic transplantation.
Regulation of FcεRI-mediated degranulation by an adaptor protein 3BP2 in rat basophilic leukemia RBL-2H3 cells
Authors: Sada Kiyonao , Miah S. M. Shahjahan , Maeno Koichiro , Kyo Shinkou , Qu Xiujuan , Yamamura Hirohei
Published: August 2002

Aggregation of high-affinity IgE receptor FcεRI induces sequential activation of nonreceptor-type protein-tyrosine kinases and subsequent tyrosine phosphorylation of cellular proteins, leading to degranulation in mast cells. A hematopoietic cell–specific adaptor protein, 3BP2, that was originally identified as an Abl SH3-binding protein was rapidly tyrosine phosphorylated by the aggregation of FcεRI on rat basophilic leukemia RBL-2H3 cells. Tyrosine phosphorylation of 3BP2 did not depend on calcium influx from external sources. To examine the role of 3BP2 in mast cells, we overexpressed the SH2 domain of 3BP2 in the RBL-2H3 cells. Overexpression of 3BP2-SH2 domain resulted in a suppression of antigen-induced degranulation as assessed by β-hexosaminidase release. Even though overall tyrosine phosphorylation of cellular protein was not altered, antigen-mediated tyrosine phosphorylation of phospholipase C-γ (PLC-γ) and calcium mobilization were significantly suppressed in the cells overexpressing the 3BP2-SH2 domain. Furthermore, antigen stimulation induced the association of 3BP2-SH2 domain with LAT and other signaling molecule complexes in the RBL-2H3 cells. FcεRI-mediated phosphorylation of JNK and ERK was not affected by the overexpression of 3BP2-SH2 domain. These data indicate that 3BP2 functions to positively regulate the FcεRI-mediated tyrosine phosphorylation of PLC-γ and thereby the signals leading to degranulation.
A molecular compendium of genes expressed in multiple myeloma
Authors: Claudio Jaime O. , Masih-Khan Esther , Tang Hongchang , Gonçalves Jason , Voralia Michael , Li Zhi Hua , Nadeem Vincent , Cukerman Eva , Francisco-Pabalan Ofelia , Liew Choong Chin , Woodgett James R. , Stewart A. Keith
Published: August 2002

We have created a molecular resource of genes expressed in primary malignant plasma cells using a combination of cDNA library construction, 5′ end single-pass sequencing, bioinformatics, and microarray analysis. In total, we identified 9732 nonredundant expressed genes. This dataset is available as the Myeloma Gene Index (www.uhnres.utoronto.ca/akstewart_lab).Predictably, the sequenced profile of myeloma cDNAs mirrored the known function of immunoglobulin-producing, high-respiratory rate, low-cycling, terminally differentiated plasma cells. Nevertheless, approximately 10% of myeloma-expressed sequences matched only entries in the database of Expressed Sequence Tags (dbEST) or the high-throughput genomic sequence (htgs) database. Numerous novel genes of potential biologic significance were identified. We therefore spotted 4300 sequenced cDNAs on glass slides creating a myeloma-enriched microarray. Several of the most highly expressed genes identified by sequencing, such as a novel putative disulfide isomerase (MGC3178), tumor rejection antigen TRA1, heat shock 70-kDa protein 5, and annexin A2, were also differentially expressed between myeloma and B lymphoma cell lines using this myeloma-enriched microarray. Furthermore, a defined subset of 34 up-regulated and 18 down-regulated genes on the array were able to differentiate myeloma from nonmyeloma cell lines. These not only include genes involved in B-cell biology such as syndecan, BCMA, PIM2, MUM1/IRF4,and XBP1, but also novel uncharacterized genes matching sequences only in the public databases. In summary, our expressed gene catalog and myeloma-enriched microarray contains numerous genes of unknown function and may complement other commercially available arrays in defining the molecular portrait of this hematopoietic malignancy.