1,445 research outputs found

    Coping with unpleasant surprises in a complex world: Is rational choice possible in a world with positive information costs?

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    This paper provides a rational choice-based analysis of the causes and consequences of surprise events. The paper argues that ignorance may be rational, but nonetheless produce systematic mistakes, inconsistent behavior, and both pleasant and unpleasant surprises. If ignorance and unpleasant surprises are commonplace and relevant for individual and group decisionmaking, we should observe standing institutions for dealing with them - and we do. Insofar as surprises are consistent with rational choice models, but left outside most models, it can be argued that these methodological choices mistakenly limit the scope of rational choicebased research. --Ignorance,Rational Ignorance,Natural Ignorance,Bounded Rationality,Rational Choice,Biased Expectations,Crisis Management,Social Insurance,Bailouts,Economics of Information

    Nuclear Muon Capture on the Proton and 3He within the Standard Model and Beyond

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    Nuclear muon capture on the proton and 3^3He is considered both within and beyond the Standard Model in terms as general as is possible. Explicit and precise analytic expressions for all possible observables are given, assuming only a Dirac neutrino in the limit of vanishing mass. These results allow both for precision tests of the Standard Model and new physics, as well as for the assessment of the potential physics reach of experiments designed to measure specific observables. Using these expressions, stringent constraints can already be inferred from a recent precision measurement of the statistical capture rate on 3^3He. Likewise, similar constraints should follow the completion of a precision measurement in progress of the singlet capture rate on the proton.Comment: 36 pages, no figures, plain LaTeX fil

    The Fairfax County Hoarding Task Force

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    Educational Objectives 1. Describe the reasons for forming the Fairfax County Hoarding Task Force. 2. Explain the organizational makeup of the Hoarding Task Force. 3. Understand the risk factors in hoarding and what is being done to address them

    Symmetry Tests of the Electroweak Interaction from Muon Capture on 3He

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    Precision measurements in muon capture on 3He to the triton channel provide for interesting tests of the charged electroweak interaction, whether within the Standard Model or beyond it. Based on the statistical capture rate and the triton asymmetry, both the object of recent and on-going experiments using polarised 3He targets, examples of such tests are presented, and shown to lead to stringent complementary constraints for which further dedicated experimental as well as theoretical efforts are required.Comment: 13 pages, uses Elsevier's LaTeX packag

    Hyperfine Populations Prior to Muon Capture

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    It is shown that the 1S level hyperfine populations prior to muon capture will be statistical when either target or beam are unpolarised independent of the atomic level at which the hyperfine interaction becomes appreciable. This assertion holds in the absence of magnetic transitions during the cascade and is true because of minimal polarisation after atomic capture and selective feeding during the cascade.Comment: (revtex, 6 preprint pages, no figures

    The pd3HΛK+pd\to ^3H_\Lambda K^+ reaction cross section

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    The one- and two-step mechanisms of the pd3HΛK+pd\to ^3H_\Lambda K^+ reaction in the range of incident proton kinetic energy 1.13-3.0 GeV have been investigated. A remarkable peculiarity of the two-step mechanism which incorporates subprocesses ppdπ+pp\to d\pi ^+ and π+nK+Λ\pi^+n\to K^+\Lambda is the so called velocity matching providing the presence of all intermediate particles nearly to the on-mass-shell. The differential cross section has been calculated using a realistic model for the hypertritium 3HΛ^3H_\Lambda wave function. The maximum value of the cross section is estimated as \sim 1nb/sr. The contribution of the one-step mechanism with the elementary process pNNKΛpN\to NK\Lambda into the cross section has been found to be two - three orders of magnitude smaller in comparison with the two-step mechanism.Comment: 10 pages, Latex, 3 Postscript figure

    Photoproduction of the Hypertriton

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    In the framework of the impulse approximation we study the photoproduction of the hypertriton Λ3^3_{\Lambda}H by using realistic 3^3He wave functions obtained as solutions of Faddeev equations with the Reid soft-core potential for different Λ3^3_{\Lambda}H wave functions. We obtain relatively small cross sections of the order of 1 nb. We also find that the influence of Fermi motion is important, while the effect of different off-shell assumptions on the cross section is not too significant.Comment: 6 pages in Latex. Talk given at the 15th International Conference on Few-Body Problems in Physics, Groningen, Netherlands, 22-26 July 1997. To be published in Nucl. Phys.

    Final state interaction effects in mu-capture induced two-body decay of 3He

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    The mu-capture process on 3He leading to a neutron, a deuteron and a mu-neutrino in the final state is studied. Three-nucleon Faddeev wave functions for the initial 3He bound and the final neutron-deuteron scattering states are calculated using the BonnB and Paris nucleon-nucleon potentials. The nuclear weak current operator is restricted to impulse approximation. Large effects on the decay rates of the final state interaction are found. The comparison to recent experimental data shows that the inclusion of final state interactions drastically improves the description of the data.Comment: 14 pages, 6 eps figure

    Spiraling Toward Usability: An Integrated Design Environment and Management System

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    Decades of innovation in designing usable (and unusable) interfaces have resulted in a plethora of guidelines, usability engineering methods, and other design tools. However, novice developers often have difficulty selecting and utilizing theory-based design tools in a coherent design process. This work introduces an integrated design environment and knowledge management system, LINK-UP. The central design record (CDR) module, provides tools to enable a guided, coherent development process. The CDR aims to prevent breakdowns occurring between design and evaluation phases both within the development team and during design knowledge reuse processes. We report on results from three case studies illustrating novice designers use of LINK-UP. A design knowledge IDE incorporating a CDR can help novice developers craft interfaces in a methodical fashion, while applying, verifying, and producing reusable design knowledge. Although LINK-UP supports a specific design domain, our IDE approach can transfer to other domains
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