3,325 research outputs found

    Cofinite Induced Subgraphs of Impartial Combinatorial Games: An Analysis of CIS-Nim

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    Given an impartial combinatorial game G, we create a class of related games (CIS-G) by specifying a finite set of positions in G and forbidding players from moving to those positions (leaving all other game rules unchanged). Such modifications amount to taking cofinite induced subgraphs (CIS) of the original game graph. Some recent numerical/heuristic work has suggested that the underlying structure and behavior of such "CIS-games" can shed new light on, and bears interesting relationships with, the original games from which they are derived. In this paper we present an analytical treatment of the cofinite induced subgraphs associated with the game of (three-heap) Nim. This constitutes one of the simplest nontrivial cases of a CIS game. Our main finding is that although the structure of the winning strategies in games of CIS-Nim can differ greatly from that of Nim, CIS-Nim games inherit a type of period-two scale invariance from the original game of Nim.Comment: 26 pages, 5 figure

    Cofinite Induced Subgraphs of Impartial Combinatorial Games: An Analysis of CIS-Nim

    Get PDF
    Given an impartial combinatorial game G, we create a class of related games (CISG) by specifying a finite set of positions in G and forbidding players from moving to those positions (leaving all other game rules unchanged). Such modifications amount to taking cofinite induced subgraphs (CIS) of the original game graph. Some recent numerical/heuristic work has suggested that the underlying structure and behavior of such “CIS-games” can shed new light on, and bears interesting relationships with, the original games from which they are derived. In this paper we present an analytical treatment of the cofinite induced subgraphs associated with the game of (three-heap) Nim. This constitutes one of the simplest nontrivial cases of a CIS game. Our main finding is that although the structure of the winning strategies in games of CIS-Nim can differ greatly from that of Nim, CIS-Nim games inherit a type of period-two scale invariance from the original game of Nim

    Reactions at Polymer Interfaces: Transitions from Chemical to Diffusion-Control and Mixed Order Kinetics

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    We study reactions between end-functionalized chains at a polymer-polymer interface. For small chemical reactivities (the typical case) the number of diblocks formed, RtR_t, obeys 2nd order chemically controlled kinetics, Rt∌tR_t \sim t, until interfacial saturation. For high reactivities (e.g. radicals) a transition occurs at short times to 2nd order diffusion-controlled kinetics, with Rt∌t/ln⁥tR_t \sim t/\ln t for unentangled chains while t/ln⁥tt/\ln t and t1/2t^{1/2} regimes occur for entangled chains. Long time kinetics are 1st order and controlled by diffusion of the more dilute species to the interface: Rt∌t1/4R_t \sim t^{1/4} for unentangled cases, while Rt∌t1/4R_t \sim t^{1/4} and t1/8t^{1/8} regimes arise for entangled systems. The final 1st order regime is governed by center of gravity diffusion, Rt∌t1/2R_t \sim t^{1/2}.Comment: 11 pages, 3 figures, uses poliface.sty, minor changes, to appear in Europhysics Letter

    Early and rapid prediction of patency of the infarct-related coronary artery by using left ventricular wall thickness as measured by two-dimensional echocardiography

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    AbstractObjectives. The aim of this study was to determine whether echocardiography can distinguish between persistent coronary occlusion and reperfusion.Background. There are no adequate clinical or noninvasive laboratory markers to accurately predict successful reperfusion in an acute myocardial infarction.Methods. In a closed chest swine model, the effect of reperfusion on myocardial wall thickness was studied by comparing a 150-min total coronary artery occlusion (group 1) with 120 min of occlusion followed by 30 min of reperfusion (group 2) in the area of risk as measured by echocardiography. Wall thickness was measured at baseline and at 90 and 150 min.Results. In group 1 (n = 4), there was no appreciable change in mean wall thickness from 90 min to 150 min of occlusion at either end-diastole or end-systole (0.54 ± 0.02 to 0.52 ± 0.03 cm, 0.55 ± 0.03 to 0.54 ± 0.03 cm, respectively; p = NS). In contrast, in group 2 (n = 6), an increase in mean wall thickness from 0.53 ± 0.02 to 0.97 ± 0.05 cm at end-diastole and from 0.56 ± 0.04 to 1.04 ± 0.07 cm at end-systole was found from 90 min of occlusion to 30 min of reperfusion (p < 0.001). Reperfusion resulted. in an increase in wall thickness of 83 ± 11% at end-diastole and 92 ± 17% at end-systole. In contrast, persistent coronary occlusion showed minimal changes of −3.0 ± 5% at end-diastole and −2.0 ± 6% at end-systole.Conclusions. This study confirms the hypothesis that an increase in wall thickness can accurately distinguish between reperfusion and permanent coronary occlusion

    Isotopic Scaling in Nuclear Reactions

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    A three parameter scaling relationship between isotopic distributions for elements with Z≀8\leq 8 has been observed that allows a simple description of the dependence of such distributions on the overall isospin of the system. This scaling law (termed iso-scaling) applies for a variety of reaction mechanisms that are dominated by phase space, including evaporation, multifragmentation and deeply inelastic scattering. The origins of this scaling behavior for the various reaction mechanisms are explained. For multifragmentation processes, the systematics is influenced by the density dependence of the asymmetry term of the equation of state.Comment: 10 Pages, 2 Figure

    La LĂłgica de los trabajadores : un estudio sobre la racionalidad, la autonomĂ­a y la coherencia de las prĂĄcticas y los significados de los trabajadores

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    En parte de la literatura reciente sobre sociologĂ­a del trabajo y de las organizaciones, el reconocimiento del papel de los obreros como agentes ha venido de la mano de una concepciĂłn de la subjetividad de los trabajadores como un "efecto" contradictorio e inconsistente de las relaciones de poder. Frente a esta concepciĂłn, y a partir del anĂĄlisis de dieciocho entrevistas realizadas a trabajadores de una multinacional automovilĂ­stica de Barcelona, se pondrĂĄ de manifiesto en este artĂ­culo el carĂĄcter innovador, autĂłnomo, lĂłgico y coherente del conjunto de los significados que guĂ­an las acciones cotidianas de los trabajadores. En el caso analizado, los trabajadores guĂ­an sus acciones cotidianas bajo la idea de la necesidad de respetar un cĂłdigo Ă©tico de comportamiento compuesto por una serie de principios morales bien trabados. Las acciones de compromiso y resistencia, que algunos autores presentan como contradictorias, aparecen aquĂ­ como acciones coherentes con una serie de principios Ă©ticos, y por tanto, como racionalmente ajustadas a valores.While some of the recent literature addressing the sociology of work and organizations recognizes the role of workers' agency, it always includes the concept of workers' subjectivity as a contradictory and inconsistent "effect" of power relations. In contrast to this approach, using the analysis of eighteen interviews conducted with workers of an automotive multinational in Barcelona, it will be shown in this article the innovative, autonomous, logical and coherent character of the set of meanings guiding workers' everyday actions. In this case study, the everyday actions of the workers are guided by a belief in the necessity of an ethical code of behavior. This code is composed of a set of congruent moral principles. The actions of resistance and commitment, presented by several authors as contradictory, appear being consistent with a set of ethical principles, and therefore, as value-rational action

    Giving voters what they want? Party orientation perceptions and preferences in the British electorate

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    Some of the most important propositions in the political marketing literature hinge on assumptions about the electorate. In particular, voters are presumed to react in different ways to different orientations or postures. Yet there are theoretical reasons for questioning some of these assumptions, and certainly they have seldom been empirically tested. Here, we focus on one prominent example of political marketing research: Lees-Marshment’s orientations’ model. We investigate how the public reacts to product and market orientation, whether they see a trade-off between the two (a point in dispute among political marketing scholars), and whether partisans differ from non-partisan voters by being more inclined to value product over market orientation. Evidence from two mass sample surveys of the British public (both conducted online by YouGov) demonstrates important heterogeneity within the electorate, casts doubt on the core assumptions underlying some political marketing arguments and raises broader questions about what voters are looking for in a party
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