2,268 research outputs found

    Pre-K Counts in Pennsylvania for Youngsters' Early School Success: Authentic Outcomes for an Innovative Prevention and Promotion Initiative

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    Examines the research base for the efficacy of early childhood education. Evaluates Pennsylvania's Pre-K Counts programs, including participants' characteristics, impact and quality of programs and partnerships, lessons learned, and recommendations

    Comment on 'Stability of the semiclassical Einstein equation'

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    Some mathematical errors of the paper commented upon [W.-M. Suen, Phys. Rev. D 40, (1989) 315] are corrected.Comment: 3 pages, LaTeX, reprinted from Phys. Rev. D 50 (1994) 545

    Media as watchdogs: The role of news media in electoral competition

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    We develop an equilibrium model to analyze the role of the media in electoral competition. When policy payoffs are state-dependent, party policies do not converge to the median voter's ideal policy if the media report only party policies. News analysis about the state, though possibly biased, can discipline off-equilibrium deviations and make the parties adopt more centrist policies. Since voters are rational, the party favored by the media need not win with a higher probability. Instead, media bias may reduce the effectiveness of electoral competition and lead to more polarized policies. © 2009 Elsevier B.V. All rights reserved.postprin

    The classical-quantum divergence of complexity in modelling spin chains

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    The minimal memory required to model a given stochastic process - known as the statistical complexity - is a widely adopted quantifier of structure in complexity science. Here, we ask if quantum mechanics can fundamentally change the qualitative behaviour of this measure. We study this question in the context of the classical Ising spin chain. In this system, the statistical complexity is known to grow monotonically with temperature. We evaluate the spin chain's quantum mechanical statistical complexity by explicitly constructing its provably simplest quantum model, and demonstrate that this measure exhibits drastically different behaviour: it rises to a maximum at some finite temperature then tends back towards zero for higher temperatures. This demonstrates how complexity, as captured by the amount of memory required to model a process, can exhibit radically different behaviour when quantum processing is allowed.Comment: 9 pages, 3 figures, comments are welcom

    Marital transfer and intra-household allocation: A Nash-bargaining analysis

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    This paper explores the implications of inter-generational marital transfers on the allocation of resources within a conjugal household. Adopting a Nash-bargaining framework with alternative models of the threat points, it is argued that parents have greater incentive to make transfers to a married child than to a single child because of the efficiency gains from joint consumption and production of family public goods and because of the increase in bargaining power of the child in the allocation of private consumption. Such transfers also enhance marital stability by increasing the efficiency gains from marriage. © 2002 Elsevier Science B.V. All rights reserved.postprin

    MACS: Multi-agent COTR system for Defense Contracting

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    The field of intelligent multi-agent systems has expanded rapidly in the recent past. Multi-agent architectures and systems are being investigated and continue to develop. To date, little has been accomplished in applying multi-agent systems to the defense acquisition domain. This paper describes the design, development, and related considerations of a multi-agent system in the area of procurement and contracting for the defense acquisition community

    Spontaneous Interlayer Charge Transfer near the Magnetic Quantum Limit

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    Experiments reveal that a confined electron system with two equally-populated layers at zero magnetic field can spontaneously break this symmetry through an interlayer charge transfer near the magnetic quantum limit. New fractional quantum Hall states at unusual total filling factors such as \nu = 11/15 (= 1/3 + 2/5) stabilize as signatures that the system deforms itself, at substantial electrostatic energy cost, in order to gain crucial correlation energy by "locking in" separate incompressible liquid phases at unequal fillings in the two layers (e.g., layered 1/3 and 2/5 states in the case of \nu = 11/15).Comment: 4 pages, 4 figures (1 color) included in text. Related papers at http://www.ee.princeton.edu/~hari/papers.htm

    Surveying structural complexity in quantum many-body systems

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    Quantum many-body systems exhibit a rich and diverse range of exotic behaviours, owing to their underlying non-classical structure. These systems present a deep structure beyond those that can be captured by measures of correlation and entanglement alone. Using tools from complexity science, we characterise such structure. We investigate the structural complexities that can be found within the patterns that manifest from the observational data of these systems. In particular, using two prototypical quantum many-body systems as test cases - the one-dimensional quantum Ising and Bose-Hubbard models - we explore how different information-theoretic measures of complexity are able to identify different features of such patterns. This work furthers the understanding of fully-quantum notions of structure and complexity in quantum systems and dynamics.Comment: 9 pages, 5 figure

    The Shapiro Conjecture: Prompt or Delayed Collapse in the head-on collision of neutron stars?

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    We study the question of prompt vs. delayed collapse in the head-on collision of two neutron stars. We show that the prompt formation of a black hole is possible, contrary to a conjecture of Shapiro which claims that collapse is delayed until after neutrino cooling. We discuss the insight provided by Shapiro's conjecture and its limitation. An understanding of the limitation of the conjecture is provided in terms of the many time scales involved in the problem. General relativistic simulations in the Einstein theory with the full set of Einstein equations coupled to the general relativistic hydrodynamic equations are carried out in our study.Comment: 4 pages, 7 figure
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