2,886 research outputs found

    Preservice Teachers\u27 Epistemological Beliefs: A Study of Student and Course Characteristics

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    The research project described herein was designed to measure teacher education students\u27 epistemological beliefs. Teacher education students\u27 epistemological beliefs were compared according to participants\u27 academic and demographic characteristics as well as characteristics of the courses in which students are enrolled at the time of study data collection. Participants included teacher education students currently studying in Old Dominion University\u27s Darden College of Education. Results indicated that, while participants\u27 epistemological beliefs and the development thereof are both, at times, related to their demographic and academic characteristics as well as the characteristics of the courses in which they were enrolled during the study, sometimes as statistically significant levels, further research needs to be conducted in order to further characterize the nature of these relationships, taking into consideration variables not accounted for in the current study

    Modeling Human Ad Hoc Coordination

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    Whether in groups of humans or groups of computer agents, collaboration is most effective between individuals who have the ability to coordinate on a joint strategy for collective action. However, in general a rational actor will only intend to coordinate if that actor believes the other group members have the same intention. This circular dependence makes rational coordination difficult in uncertain environments if communication between actors is unreliable and no prior agreements have been made. An important normative question with regard to coordination in these ad hoc settings is therefore how one can come to believe that other actors will coordinate, and with regard to systems involving humans, an important empirical question is how humans arrive at these expectations. We introduce an exact algorithm for computing the infinitely recursive hierarchy of graded beliefs required for rational coordination in uncertain environments, and we introduce a novel mechanism for multiagent coordination that uses it. Our algorithm is valid in any environment with a finite state space, and extensions to certain countably infinite state spaces are likely possible. We test our mechanism for multiagent coordination as a model for human decisions in a simple coordination game using existing experimental data. We then explore via simulations whether modeling humans in this way may improve human-agent collaboration.Comment: AAAI 201

    Volume and homology of one-cusped hyperbolic 3-manifolds

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    Let M be a complete, finite-volume, orientable hyperbolic manifold having exactly one cusp. If we assume that pi_1(M) has no subgroup isomorphic to a genus-2 surface group, and that either (a) H_1(M;Z_p) has dimension at least 5 for some prime p, or (b) H_1(M;Z_2) has dimension at least 4, and the subspace of H^2(M;Z_2) spanned by the image of the cup product has dimension at most 1, then vol M > 5.06 If we assume that H_1(M;Z_2) has dimension at least 7, and that the compact core of M does not contain a genus-2 closed incompressible surface, then vol M > 5.06.Comment: 31 pages. This version agrees with the published version of the paper, except that an error in the published abstract has been corrected. In particular, the result which applies to manifolds with mod 2 homology of dimension at least 7 is stronger and has a shorter proof than the corresponding result in version

    Alien Tort Cases Will Survive Supreme Court Trim, Write Commentators

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    For over four decades, the Alien Tort Statute has served as a central battleground in some of the country’s (and world’s) most significant international human rights litigation. Following a trend in its ATS jurisprudence that started with its opinion in Sosa v. Alvarez-Machain, the Supreme Court recently trimmed the statute’s scope yet further. In Jesner v. Arab Bank PLC, the Court held that suits arising under the ATS did not extend to claims against corporations (at least some of them, a nuance explained below). Once again, postdecisional commentary decried the demise of ATS suits and a blow, more generally, to the cause of human rights. The reality, however, is much more complex. Despite Jesner’s holding, several potentially viable avenues for ATS litigation remain. This essay maps out three anticipated battlegrounds in future ATS litigation in the wake of Jesner

    Modeling human ad hoc coordination

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    Whether in groups of humans or groups of computer agents, collaboration is most effective between individuals who have the ability to coordinate on a joint strategy for collective action. However, in general a rational actor will only intend to coordinate if that actor believes the other group members have the same intention. This circular dependence makes rational coordination difficult in uncertain environments if communication between actors is unreliable and no prior agreements have been made. An important normative question with regard to coordination in these ad hoc settings is therefore how one can come to believe that other actors will coordinate, and with regard to systems involving humans, an important empirical question is how humans arrive at these expectations. We introduce an exact algorithm for computing the infinitely recursive hierarchy of graded beliefs required for rational coordination in uncertain environments, and we introduce a novel mechanism for multiagent coordination that uses it. Our algorithm is valid in any environment with a finite state space, and extensions to certain countably infinite state spaces are likely possible. We test our mechanism for multiagent coordination as a model for human decisions in a simple coordination game using existing experimental data. We then explore via simulations whether modeling humans in this way may improve human-Agent collaboration

    Binary black hole initial data for numerical general relativity based on post-Newtonian data

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    With the goal of taking a step toward the construction of astrophysically realistic initial data for numerical simulations of black holes, we for the first time derive a family of fully general relativistic initial data based on post-2-Newtonian expansions of the 3-metric and extrinsic curvature without spin. It is expected that such initial data provide a direct connection with the early inspiral phase of the binary system. We discuss a straightforward numerical implementation, which is based on a generalized puncture method. Furthermore, we suggest a method to address some of the inherent ambiguity in mapping post-Newtonian data onto a solution of the general relativistic constraints.Comment: 13 pages, 8 figures, RevTex

    Managing fire-prone forests in the western United States

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    The management of fire-prone forests is one of the most controversial natural resource issues in the US today, particularly in the west of the country. Although vegetation and wildlife in these forests are adapted to fire, the historical range of fire frequency and severity was huge. When fire regimes are altered by human activity, major effects on biodiversity and ecosystem function are unavoidable. We review the ecological science relevant to developing and implementing fire and fuel management policies for forests before, during, and after wildfires. Fire exclusion led to major deviations from historical variability in many dry, low-elevation forests, but not in other forests, such as those characterized by high severity fires recurring at intervals longer than the period of active fire exclusion. Restoration and management of fire-prone forests should be precautionary, allow or mimic natural fire regimes as much as possible, and generally avoid intensive practices such as post-fire logging and planting

    Gauge conditions for long-term numerical black hole evolutions without excision

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    Numerical relativity has faced the problem that standard 3+1 simulations of black hole spacetimes without singularity excision and with singularity avoiding lapse and vanishing shift fail after an evolution time of around 30-40M due to the so-called slice stretching. We discuss lapse and shift conditions for the non-excision case that effectively cure slice stretching and allow run times of 1000M and more.Comment: 19 pages, 14 figures, REVTeX, Added a missing Acknowledgmen
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