74 research outputs found

    Short-term effects of marijuana smoking on cognitive behavior in experienced male users

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    The effects of smoking marijuana on the ability to use abstract concepts was tested in 12 experienced marijuana users. Each subject was tested three times, after smoking prepared 300 mg cigarettes containing either 0, 1.5 or 2.9% δ 9 -THC in different sessions according to a Latin Square design. The same number of whole and/or partial cigarettes was smoked by each subject in each of the three sessions. This was determined for individual subjects by the number of 2.9% δ 9 -THC marijuana cigarettes that the subject had been willing to smoke in a pre-experimental session up to a maximum of 1200 mg. The following tests of concept formation and usage were used: 1. a letter series test; 2. a word grouping test; 3. a conceptual clustering memory test; 4. a closure speed test; 5. Witkin's Embedded Figures Test; 6. a size weight illusion test; 7. Luchin's Water Jar Test; 8. Luchin's Hidden Word Test; and 9. an anagram test. Marijuana smoking led to a dose-related impairment on the letter series, word grouping, closure speed, and Embedded Figures test. Performance on the size-weight illusion, Luchin's Water Jar, Luchin's Hidden Word, and the anagram tests were unaffected. Conceptual clustering decreased after marijuana smoking. In most cases only the differences between 0 and 2.9% δ 9 -THC marijuana were statistically significant.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46387/1/213_2004_Article_BF00429295.pd

    D meson hadronic decays at CLEO-c

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    Thesis (Ph. D.)--University of Rochester. Dept. of Physics and Astronomy, 2009.[Abstract would not render]--Submitter

    Ds exclusive semileptonic decays at CLEO-c

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    Thesis (Ph. D.)--University of Rochester. Dept. of Physics and Astronomy, 2011.We are interested in measuring the exclusive semileptonic decays of the Ds to greater precision because it is the least extensively studied of the ground state charmed mesons, and greater knowledge of the Ds's decays may give information on related processes. We have studied semileptonic decay of the Ds meson using the full data set collected near the D*sDs peak production energy of 4170 MeV with the CLEO-c detector. We have made improved measurements of the branching fractions of Cabibbo favored semileptonic decays [formula would not render] and [formula would not render]. We have also made observations of the branching fractions of Cabibbo suppressed semileptonic decays [formula would not render] and [formula would not render]. These branching fractions are the most precisely measured to date

    Impact on &gamma;/&phi;<sub>3</sub> measurement from CLEO-c binned <I>D</I><sup>0</sup> --> <I>K<sup>0</sup><sub>S,L<sup>&pi;+&pi;<sup>-</sup></sup></sub></I> Dalitz analysis

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    Thesis (Ph. D.)--University of Rochester. Dept. of Physics, 2009.[Unable to render in HTML. Please see PDF.

    Opposite-sign dileptons from B-meson decay

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    Thesis (Ph. D.)--University of Rochester. Dept. of Physics and Astronomy, 1987.Dilepton production in B-meson decay has been studied using the CLEO detector at CESR (Cornell Electron Storage Ring). Two processes have been investigated: the decay B --> ℣X, ; ℣ -> ℓ+ℓ- and the flavor-changing neutral-current decay B --> ℓ+ℓ-X. The inclusive branching ratio of B into [sic]'s has been measured to be (1.09 ± 0.16 ± 0.21)%. The exclusive branching ratios, B- --> ℣K- and B0 --> ℣K*o, have also been measured. From these events the masses of both the charged and neutral B meson were determined. The mass difference has been measured to be 1.1 ± 2.1 MeV. The ℣ momentum spectrum suggests a substantial amount of two-body decays. Implications of these decays on color suppression are discussed. A search has been conducted for the flavor-changing neutral-current decay B --> ℓ+ℓ-X, using a variety of methods to reduce dilepton backgrounds. No evidence for flavor-changing neutral-current production has been found. An upper limit of 1.6x10-3 at 90% CL has been obtained. This limit is consistent with standard model predictions
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