72 research outputs found

    Dialectical Inquiry: A Structured Qualitative Research Method

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    This paper presents Dialectical Inquiry (DI) as a structured qualitative research method for studying participant models of organizational processes. The method is applied to rich secondary anecdotal data on technology transfer, gathered by subject-matter experts in a large firm. DI assumes that the imposition of a dialectical structure will produce emergent theories in tacit use by organizational actors. As such, it serves as a meta-structure for grounded rese arch. Three competing models were discovered in the data. Each model was analyzed in the context of other models to reveal governing assumptions and counter assumptions. It is demonstrated that each model grasps essential truths, but is necessarily incomplete, and would fail due to internal contradictions. The internal and external validity of the results were tested in a manner consistent with qualitative researc

    Investigating diet as the source of tetrodotoxin in Pleurobranchaea maculata

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    The origin of tetrodotoxin (TTX) is highly debated; researchers have postulated either an endogenous or exogenous source with the host accumulating TTX symbiotically or via food chain transmission. The aim of this study was to determine whether the grey side-gilled sea slug (Pleurobranchaea maculata) could obtain TTX from a dietary source, and to attempt to identify this source through environmental surveys. Eighteen non-toxic P. maculata were maintained in aquariums and twelve were fed a TTX-containing diet. Three P. maculata were harvested after 1 h, 24 h, 17 days and 39 days and TTX concentrations in their stomach, gonad, mantle and remaining tissue/fluids determined using liquid chromatography-mass spectrometry. Tetrodotoxin was detected in all organs/tissue after 1 h with an average uptake of 32%. This decreased throughout the experiment (21%, 15% and 9%, respectively). Benthic surveys at sites with dense populations of toxic P. maculata detected very low or no TTX in other organisms. This study demonstrates that P. maculata can accumulate TTX through their diet. However, based on the absence of an identifiable TTX source in the environment, in concert with the extremely high TTX concentrations and short life spans of P. maculata, it is unlikely to be the sole TTX source for this species

    Conservation tillage : costs and returns (1993)

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    This publication briefly describes tillage systems and estimates costs and returns on a typical farm.Reviewed October 1, 1993

    Conservation tillage : costs and returns

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    "This guide sheet briefly describes tillage systems and estimates costs and returns on a typical farm."--First page.David E. Ervin, Coy G. McNabb, and Myron D. Bennett (Department of Agricultural Economics, College of Agriculture); Dallas D. Schafer (U.S.D.A. Soil Conservation Service, Columbia, Missouri)New 7/83/10

    LOOC UP: Locating and observing optical counterparts to gravitational wave bursts

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    Gravitational wave (GW) bursts (short duration signals) are expected to be associated with highly energetic astrophysical processes. With such high energies present, it is likely these astrophysical events will have signatures in the EM spectrum as well as in gravitational radiation. We have initiated a program, "Locating and Observing Optical Counterparts to Unmodeled Pulses in Gravitational Waves" (LOOC UP) to promptly search for counterparts to GW burst candidates. The proposed method analyzes near real-time data from the LIGO-Virgo network, and then uses a telescope network to seek optical-transient counterparts to candidate GW signals. We carried out a pilot study using S5/VSR1 data from the LIGO-Virgo network to develop methods and software tools for such a search. We will present the method, with an emphasis on the potential for such a search to be carried out during the next science run of LIGO and Virgo, expected to begin in 2009.Comment: 11 pages, 2 figures; v2) added acknowledgments, additional references, and minor text changes v3) added 1 figure, additional references, and minor text changes. v4) Updated references and acknowledgments. To be published in the GWDAW 12 Conf. Proc. by Classical and Quantum Gravit

    HLA-E–dependent Presentation of Mtb-derived Antigen to Human CD8+ T Cells

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    Previous studies in mice and humans have suggested an important role for CD8+ T cells in host defense to Mtb. Recently, we have described human, Mtb-specific CD8+ cells that are neither HLA-A, B, or C nor group 1 CD1 restricted, and have found that these cells comprise the dominant CD8+ T cell response in latently infected individuals. In this report, three independent methods are used to demonstrate the ability of these cells to recognize Mtb-derived antigen in the context of the monomorphic HLA-E molecule. This is the first demonstration of the ability of HLA-E to present pathogen-derived antigen. Further definition of the HLA-E specific response may aid development of an effective vaccine against tuberculosis

    The Muon Anomalous Magnetic Moment and the Standard Model

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    The muon anomalous magnetic moment measurement, when compared with theory, can be used to test many extensions to the standard model. The most recent measurement made by the Brookhaven E821 Collaboration reduces the uncertainty on the world average of a_mu to 0.7 ppm, comparable in precision to theory. This paper describes the experiment and the current theoretical efforts to establish a correct standard model reference value for the muon anomaly.Comment: Plenary Talk; PANIC'02 XVI Particles and Nuclear International Conference, Osaka, Japan; Sept. 30 - Oct. 4, 2002; Report describes the published 0.7 ppm result and updates the theory statu

    P-wave excited baryons from pion- and photo-induced hyperon production

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    We report evidence for N(1710)P11N(1710)P_{11}, N(1875)P11N(1875)P_{11}, N(1900)P13N(1900)P_{13}, Δ(1600)P33\Delta(1600)P_{33}, Δ(1910)P31\Delta(1910)P_{31}, and Δ(1920)P33\Delta(1920)P_{33}, and find indications that N(1900)P13N(1900)P_{13} might have a companion state at 1970\,MeV. The controversial Δ(1750)P31\Delta(1750)P_{31} is not seen. The evidence is derived from a study of data on pion- and photo-induced hyperon production, but other data are included as well. Most of the resonances reported here were found in the Karlsruhe-Helsinki (KH84) and the Carnegie-Mellon (CM) analyses but were challenged recently by the Data Analysis Center at GWU. Our analysis is constrained by the energy independent πN\pi N scattering amplitudes from either KH84 or GWU. The two πN\pi N amplitudes from KH84 or GWU, respectively, lead to slightly different πN\pi N branching ratios of contributing resonances but the debated resonances are required in both series of fits.Comment: 22 pages, 28 figures. Some additional sets of data are adde

    Searching for a Stochastic Background of Gravitational Waves with LIGO

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    The Laser Interferometer Gravitational-wave Observatory (LIGO) has performed the fourth science run, S4, with significantly improved interferometer sensitivities with respect to previous runs. Using data acquired during this science run, we place a limit on the amplitude of a stochastic background of gravitational waves. For a frequency independent spectrum, the new limit is ΩGW<6.5×105\Omega_{\rm GW} < 6.5 \times 10^{-5}. This is currently the most sensitive result in the frequency range 51-150 Hz, with a factor of 13 improvement over the previous LIGO result. We discuss complementarity of the new result with other constraints on a stochastic background of gravitational waves, and we investigate implications of the new result for different models of this background.Comment: 37 pages, 16 figure

    Search for gravitational wave bursts in LIGO's third science run

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    We report on a search for gravitational wave bursts in data from the three LIGO interferometric detectors during their third science run. The search targets subsecond bursts in the frequency range 100-1100 Hz for which no waveform model is assumed, and has a sensitivity in terms of the root-sum-square (rss) strain amplitude of hrss ~ 10^{-20} / sqrt(Hz). No gravitational wave signals were detected in the 8 days of analyzed data.Comment: 12 pages, 6 figures. Amaldi-6 conference proceedings to be published in Classical and Quantum Gravit
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