2,107 research outputs found

    Monopoly quality degradation and regulation in cable television

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    Using an empirical framework based on the Mussa-Rosen model of monopoly quality choice, we calculate the degree of quality degradation in cable television markets and the impact of regulation on those choices. We find lower bounds of quality degradation ranging from 11 to 45 percent of offered service qualities. Furthermore, cable operators in markets with local regulatory oversight offer significantly higher quality, less degradation, and greater quality per dollar, despite higher prices

    Giant Antiferromagnetically Coupled Moments in a Molecule-Based Magnet with Interpenetrating Lattices

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    The molecule-based magnet [Ru2_2(O2_2CMe)4_4]3_3[Cr(CN)6_6] contains two weakly-coupled, interpenetrating sublattices in a body-centered cubic structure. Although the field-dependent magnetization indicates a metamagnetic transition from an antiferromagnet to a paramagnet, the hysteresis loop also exhibits a substantial magnetic remanance and coercive field uncharacteristic of a typical metamagnet. We demonstrate that this material behaves like two giant moments with a weak antiferromagnetic coupling and a large energy barrier between the orientations of each moment. Because the sublattice moments only weakly depend on field in the transition region, the magnetic correlation length can be directly estimated from the magnetization.Comment: 3 figure

    Hypotheses, evidence and relationships: The HypER approach for representing scientific knowledge claims

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    Biological knowledge is increasingly represented as a collection of (entity-relationship-entity) triplets. These are queried, mined, appended to papers, and published. However, this representation ignores the argumentation contained within a paper and the relationships between hypotheses, claims and evidence put forth in the article. In this paper, we propose an alternate view of the research article as a network of 'hypotheses and evidence'. Our knowledge representation focuses on scientific discourse as a rhetorical activity, which leads to a different direction in the development of tools and processes for modeling this discourse. We propose to extract knowledge from the article to allow the construction of a system where a specific scientific claim is connected, through trails of meaningful relationships, to experimental evidence. We discuss some current efforts and future plans in this area

    Evidence-Based Dialogue Maps as a research tool to evaluate the quality of school pupilsā€™ scientific argumentation

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    This pilot study focuses on the potential of Evidence-based Dialogue Mapping as a participatory action research tool to investigate young teenagersā€™ scientific argumentation. Evidence-based Dialogue Mapping is a technique for representing graphically an argumentative dialogue through Questions, Ideas, Pros, Cons and Data. Our research objective is to better understand the usage of Compendium, a Dialogue Mapping software tool, as both (1) a learning strategy to scaffold school pupilsā€™ argumentation and (2) as a method to investigate the quality of their argumentative essays. The participants were a science teacher-researcher, a knowledge mapping researcher and 20 pupils, 12-13 years old, in a summer science course for ā€œgifted and talentedā€ children in the UK. This study draws on multiple data sources: discussion forum, science teacher-researcherā€™s and pupilsā€™ Dialogue Maps, pupil essays, and reflective comments about the uses of mapping for writing. Through qualitative analysis of two case studies, we examine the role of Evidence-based Dialogue Maps as a mediating tool in scientific reasoning: as conceptual bridges for linking and making knowledge intelligible; as support for the linearisation task of generating a coherent document outline; as a reflective aid to rethinking reasoning in response to teacher feedback; and as a visual language for making arguments tangible via cartographic conventions

    Abstract Tensor Systems as Monoidal Categories

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    The primary contribution of this paper is to give a formal, categorical treatment to Penrose's abstract tensor notation, in the context of traced symmetric monoidal categories. To do so, we introduce a typed, sum-free version of an abstract tensor system and demonstrate the construction of its associated category. We then show that the associated category of the free abstract tensor system is in fact the free traced symmetric monoidal category on a monoidal signature. A notable consequence of this result is a simple proof for the soundness and completeness of the diagrammatic language for traced symmetric monoidal categories.Comment: Dedicated to Joachim Lambek on the occasion of his 90th birthda

    Quality Overprovision in Cable Television Markets

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    We measure the welfare distortions from endogenous quality choice in imperfectly competitive markets. For US cable television markets between 1997ā€“2006, prices are 33 percent to 74 percent higher and qualities 23 percent to 55 percent higher than socially optimal. Such quality overprovision contradicts classic results in the literature and our analysis shows that it results from the presence of competition from high-end satellite TV providers: without the competitive pressure from satellite companies, cable TV monopolists would instead engage in quality degradation. For welfare, quality overprovision implies cable customers would prefer smaller, lower-quality cable bundles at a lower price, amounting to a twofold increase in consumer surplus for the average consumer

    Engaging Citizens with Televised Election Debates through Online Interactive Replays

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    In this paper we tackle the crisis of political trust and public engagement with politics by investigating new methods and tools to watch and take part in televised political debates. The paper presents relevant research at the intersection of citizenship, technologies and government/democracy, and describes the motivation, requirements and design of Democratic Replay, an online interactive video replay platform that offers a persistent, customisable digital space for: (a) members of the public to express their views as they watch online videos of political events; and (b) enabling for a richer collective understanding of what goes on in these complex media events
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