115,972 research outputs found

    An Exposition of the Connection between Limit-Periodic Potentials and Profinite Groups

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    We classify the hulls of different limit-periodic potentials and show that the hull of a limit-periodic potential is a procyclic group. We describe how limit-periodic potentials can be generated from a procyclic group and answer arising questions. As an expository paper, we discuss the connection between limit-periodic potentials and profinite groups as completely as possible and review some recent results on Schroedinger operators obtained in this context

    New CLEO II Results on Charm Hadron Decays

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    We present new results on charm hadron decays from the CLEO II experiment. The D*+ width is measured for the first time, Gamma(D*+) = 96 +- 4 +- 22 keV. The semileptonic decay branching fractions are determined to be B(D+ --> Kbar*0 e+ nu_e) = (6.7 +- 0.4 +- 0.5 +- 0.4)% and B(D+ --> Kbar*0 mu+ nu_mu) = (6.5 +- 0.9 +- 0.5 +- 0.4)%. We observe evidence for Omega_c --> Omega- e+ nu_e and measure the product of the branching fraction and cross section, B(Omega_c --> Omega- e+ nu_e) x sigma(e+e- --> Omega_cX) = 42.2 +- 14.1 +- 11.9 fb. Within the framework of Heavy Quark Effective Theory, we measure in the decay Lambda+_c --> Lambda e+ nu_e the form factor ratio, R = f_2/f_1 = -0.31 +- 0.06 +- 0.06. This provides strong evidence that the form factor f_2 describing spin interactionof the s quark is non-zero. The Xi+_c lifetime is measured to be 503 +- 47 +- 18 fs. The results on branching fractions, cross section, and form factor ratio are preliminary.Comment: International Europhysics Conference on HEP, Budapest, 200

    A Novel Optical Package for ATLAS Pixel Detector

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    An optical package of novel design has been developed for the ATLAS pixel detector. The package contains two VCSELs and one PIN diode to transmit and receive optical signals. The design is based on a simple connector-type concept and is made of radiation-hard material. Several packages have been fabricated and show promising results.Comment: 3 pages, 1 figure, to be published in Proc. of the 2000 Annual Meeting of the Division of Particles and Fields of the American Physical Society, Columbus, Ohi

    Tau2000 Conference Summary

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    This is a review of some of the highlights of the 6th workshop on the physics of the tau lepton and its neutrino. This includes the test of lepton universality, measurement of Lorentz Structure, study of hadronic decays, direct evidence of tau neutrino, status of neutrino oscillations, and search for neutrinoless decays. This review concludes with a look at the prospect for tau physics in the future.Comment: 20 pages, 14 figure

    Designing learning object repositories : a thesis presented in partial fulfilment of the requirements for the degree of Master of Information Science in Information Sciences at Massey University

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    Learning object repositories are expanding rapidly into the role of independent educational systems that not only are a supplement to a traditional way of learning, but also allow users to search, exchange and re-use learning objects. The intention of this innovative technology is to have such repositories to collect a database of learning objects catalogued by the learning content management system. However, for users to perform an efficient search, these learning objects would need to use metadata standards or specifications to describe their properties. For learning objects stored within the repositories, metadata standards are often used to descibe them so users of the respositories are able to find the accurate resources they required, hence metadata standards are important elements of any learning object repository. In this paper, a courseware example is used to demonstrate how to define a set of characteristics that we want to describe for our courseware, and attempt to map the data schema in the database with the available metadata standards. The outcome is to identify a set of metadata elements that would fully describe our learning objects stored within the learning object repository, and these metadata elements will also assist instructors to create adaptable courseware that can be reused by different instructors. Metadata standard is known as a critical element for the management of learning objects, not only will it increase the accuracy of the search results, it will also provide more relevant and descriptive information about the learning objects to the searchers
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