243 research outputs found

    Crew Resource Management: A Literature Review

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    Crew Resource Management as an academic field of study has only been in existence for a relatively short period. However, because of its importance to the aviation community and the airlines in particular, there is a small but growing community of researcher and academicians that are specializing in its postulates. Despite the importance of research to the aviation industry and to aviation education, no comprehensive compendium of point specific literature exists. This void presents an obstacle for both researchers and practitioners in locating articles that may be relevant to their work. In addition, because of a narrow scope of many aviation education programs, researchers seeking information are often unaware of specificity\u27s that address the totality of any particular program. Thus, the authors set out to identify a particular point specific niche of articles relating to a particular time segment of the unfolding Crew Resource Management Training field. Using descriptive research methodology and a systematic and thorough computer methodology, three hundred eighty-five citations were identified. These then were culled of duplication and a resultant sixty-six representative articles, with abstracts were found to coincide to the period of 1993 to 1998. These were further refined to key topics of a) the current status of CRM training and research, b) evolution of CRM concepts, c) measuring methods, and d) application of CRM

    The use of embolic signal detection in multicenter trials to evaluate antiplatelet efficacy: signal analysis and quality control mechanisms in the CARESS (Clopidogrel and Aspirin for Reduction of Emboli in Symptomatic carotid Stenosis) trial

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    <p><b>Background and Purpose:</b> The CARESS (Clopidogrel and Aspirin for Reduction of Emboli in Symptomatic carotid Stenosis) trial proved the effectiveness of the combination of clopidogrel and aspirin compared with aspirin alone in reducing presence and number of microembolic signals (MES) in patients with recently symptomatic carotid stenosis. The present study aimed at installing primary and secondary quality control measures in CARESS because MES evaluation relies on subjective judgment by human experts.</p> <p><b>Methods:</b> As primary quality control, centers participating in CARESS evaluated a reference digital audio tape (DAT) before the study containing both MES and artifacts. Interobserver agreement of classifying signals as MES was expressed as proportions of specific agreement of positive ratings (ps±values). For all DATs included in CARESS (n=300), online number of MES and off-line number of MES read by the central reader were compared using correlation coefficients. As secondary control, a sample of 16 of 300 DATs was cross-validated by another independent reader (post-trial validator).</p> <p><b>Results:</b> For the reference tape, the cumulative ps±value was 0.894 based on 12 of 14 observers. Two observers with very different results improved after a training procedure. Agreement between post-trial validator and central reader was ps+=0.805, indicating very good agreement. Correlation between online evaluation and off-line evaluation of DATs was very good overall (cumulative ρ=0.84; P<0.001).</p> <p><b>Conclusion:</b> Multicenter studies using MES as outcome parameter are feasible. However, primary and secondary quality control procedures are important.</p&gt

    Staggered magnetism in LiV2_2O4_4 at low temperatures probed by the muon Knight shift

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    We report on the muon Knight shift measurement in single crystals of LiV2O4. Contrary to what is anticipated for the heavy-fermion state based on the Kondo mechanism, the presence of inhomogeneous local magnetic moments is demonstrated by the broad distribution of the Knight shift at temperatures well below the presumed "Kondo temperature" (T∗≃30T^*\simeq 30 K). Moreover, a significant fraction (≃10\simeq10 %) of the specimen gives rise to a second component which is virtually non-magnetic. These observations strongly suggest that the anomalous properties of LiV2O4 originates from frustration of local magnetic moments.Comment: 11 pages, 5 figures, sbmitted to J. Phys.: Cond. Mat

    Consensus recommendations for transcranial color-coded duplex sonography for the assessment of intracranial arteries in clinical trials on acute stroke

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    BACKGROUND AND PURPOSE: Transcranial color-coded duplex sonography has become a standard diagnostic technique to assess the intracranial arterial status in acute stroke. It is increasingly used for the evaluation of prognosis and the success of revascularization in multicenter trials. The aim of this international consensus procedure was to develop recommendations on the methodology and documentation to be used for assessment of intracranial occlusion and for monitoring of recanalization. METHODS: Thirty-five experts participated in the consensus process. The presented recommendations were approved during a meeting of the consensus group in October 2008 in Giessen, Germany. The project was an initiative of the German Competence Network Stroke and performed under the auspices of the Neurosonology Research Group of the World Federation of Neurology. RESULTS: Recommendations are given on how examinations should be performed in the time-limited situation of acute stroke, including criteria to assess the quality of the acoustic bone window, the use of echo contrast agents, and the evaluation of intracranial vessel status. The important issues of the examiners' training and experience, the documentation, and analysis of study results are addressed. One central aspect was the development of standardized criteria for diagnosis of arterial occlusion. A transcranial color-coded duplex sonography recanalization score based on objective hemodynamic criteria is introduced (consensus on grading intracranial flow obstruction [COGIF] score). CONCLUSIONS: This work presents consensus statements in an attempt to standardize the application of transcranial color-coded duplex sonography in the setting of acute stroke research, aiming to improve the reliability and reproducibility of the results of future stroke studies

    Treatment of posttraumatic and focal osteoarthritic cartilage defects of the knee with autologous polymer-based three-dimensional chondrocyte grafts: 2-year clinical results

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    Autologous chondrocyte implantation (ACI) is an effective clinical procedure for the regeneration of articular cartilage defects. BioSeedÂź-C is a second-generation ACI tissue engineering cartilage graft that is based on autologous chondrocytes embedded in a three-dimensional bioresorbable two-component gel-polymer scaffold. In the present prospective study, we evaluated the short-term to mid-term efficacy of BioSeed-C for the arthrotomic and arthroscopic treatment of posttraumatic and degenerative cartilage defects in a group of patients suffering from chronic posttraumatic and/or degenerative cartilage lesions of the knee. Clinical outcome was assessed in 40 patients with a 2-year clinical follow-up before implantation and at 3, 6, 12, and 24 months after implantation by using the modified Cincinnati Knee Rating System, the Lysholm score, the Knee injury and Osteoarthritis Outcome Score, and the current health assessment form (SF-36) of the International Knee Documentation Committee, as well as histological analysis of second-look biopsies. Significant improvement (p < 0.05) in the evaluated scores was observed at 1 and/or 2 years after implantation of BioSeed-C, and histological staining of the biopsies showed good integration of the graft and formation of a cartilaginous repair tissue. The Knee injury and Osteoarthritis Outcome Score showed significant improvement in the subclasses pain, other symptoms, and knee-related quality of life 2 years after implantation of BioSeed-C in focal osteoarthritic defects. The results suggest that implanting BioSeed-C is an effective treatment option for the regeneration of posttraumatic and/or osteoarthritic defects of the knee

    Protein kinase Ymr291w/Tda1 is essential for glucose signaling in Saccharomyces cerevisiae on the level of hexokinase isoenzyme ScHxk2 phosphorylation

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    The enzyme ScHxk2 of Saccharomyces cerevisiae is a dual-function hexokinase that besides its catalytic role in glycolysis is involved in the transcriptional regulation of glucose-repressible genes. Relief from glucose repression is accompanied by the phosphorylation of the nuclear fraction of ScHxk2 at serine 15 and the translocation of the phosphoenzyme into the cytosol. Different studies suggest different serine/threonine protein kinases, Ymr291w/Tda1 or Snf1, to accomplish ScHxk2-S15 phosphorylation. The current paper provides evidence that Ymr291w/Tda1 is essential for that modification while protein kinases Ydr477w/Snf1, Ynl307c/Mck1, Yfr014c/Cmk1 and Ykl126w/Ypk1, which co-purified during Ymr291w/Tda1 tandem affinity purification, as well as protein kinases PKA and PKB homolog Sch9 are dispensable. Taking into account the detection of a significantly higher amount of the Ymr291w/Tda1 protein in cells grown in low-glucose media as compared to a high-glucose environment, Ymr291w/Tda1 is likely to contribute to glucose signaling in Saccharomyces cerevisiae on the level of ScHxk2-S15 phosphorylation in a situation of limited external glucose availability. The evolutionary conservation of amino acid residue serine 15 in yeast hexokinases and its phosphorylation is illustrated by the finding that YMR291W/TDA1 of Saccharomyces cerevisiae and the homologous KLLA0A09713 gene of Kluyveromyces lactis allow for cross-complementation of the respective protein kinase single-gene deletion strains

    Hierarchical self-entangled carbon nanotube tube networks

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    R.A. gratefully acknowledges partial project funding by the Deutsche Forschungsgemeinschaft (DFG) contract AD183-17-1 as well as in the framework of the GRK 2154 and FOR 1616, and support from the European Comission in the framework of the Graphene FET Flagship. N.M.P. is supported by the European Research Council ERC PoC 2015 SILKENE No. 693670 and by the European Commission H2020 under the Graphene FET Flagship (WP14 “Polymer Composites” No. 696656) and under the FET proactive (“Neurofibres” No. 732344). S.S. acknowledges financial support from SILKENE. This work was partly supported by the Leverhulme Trust project CARBTRIB to S.N.G. We acknowledge financial support by Land Schleswig Holstein within the funding program “Open Access Publikationsfonds”. Furthermore, we thank Heather Cavers for proofreading and correcting the manuscript

    Decrease in expression of bone morphogenetic proteins 4 and 5 in synovial tissue of patients with osteoarthritis and rheumatoid arthritis

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    Bone morphogenetic proteins (BMPs) have been identified as important morphogens with pleiotropic functions in regulating the development, homeostasis and repair of various tissues. The aim of this study was to characterize the expression of BMPs in synovial tissues under normal and arthritic conditions. Synovial tissue from normal donors (ND) and from patients with osteoarthritis (OA) and rheumatoid arthritis (RA) were analyzed for BMP expression by using microarray hybridization. Differential expression of BMP-4 and BMP-5 was validated by semiquantitative RT-PCR, in situ hybridization and immunohistochemistry. Activity of arthritis was determined by routine parameters for systemic inflammation, by histological scoring of synovitis and by semiquantitative RT-PCR of IL-1ÎČ, TNF-α, stromelysin and collagenase I in synovial tissue. Expression of BMP-4 and BMP-5 mRNA was found to be significantly decreased in synovial tissue of patients with RA in comparison with ND by microarray analysis (p < 0.0083 and p < 0.0091). Validation by PCR confirmed these data in RA (p < 0.002) and also revealed a significant decrease in BMP-4 and BMP-5 expression in OA compared with ND (p < 0.015). Furthermore, histomorphological distribution of both morphogens as determined by in situ hybridization and immunohistochemistry showed a dominance in the lining layer of normal tissues, whereas chronically inflamed tissue from patients with RA revealed BMP expression mainly scattered across deeper layers. In OA, these changes were less pronounced with variable distribution of BMPs in the lining and sublining layer. BMP-4 and BMP-5 are expressed in normal synovial tissue and were found decreased in OA and RA. This may suggest a role of distinct BMPs in joint homeostasis that is disturbed in inflammatory and degenerative joint diseases. In comparison with previous reports, these data underline the complex impact of these factors on homeostasis and remodeling in joint physiology and pathology

    Simulation of the growth of the 3D Rayleigh-Taylor instability in Supernova Remnants using an expanding reference frame

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    Context: The Rayleigh-Taylor instabilities generated by the deceleration of a supernova remnant during the ejecta-dominated phase are known to produce finger-like structures in the matter distribution which modify the geometry of the remnant. The morphology of supernova remnants is also expected to be modified when efficient particle acceleration occurs at their shocks. Aims: The impact of the Rayleigh-Taylor instabilities from the ejecta-dominated to the Sedov-Taylor phase is investigated over one octant of the supernova remnant. We also study the effect of efficient particle acceleration at the forward shock on the growth of the Rayleigh-Taylor instabilities. Methods: We modified the Adaptive Mesh Refinement code RAMSES to study with hydrodynamic numerical simulations the evolution of supernova remnants in the framework of an expanding reference frame. The adiabatic index of a relativistic gas between the forward shock and the contact discontinuity mimics the presence of accelerated particles. Results: The great advantage of the super-comoving coordinate system adopted here is that it minimizes numerical diffusion at the contact discontinuity, since it is stationary with respect to the grid. We propose an accurate expression for the growth of the Rayleigh-Taylor structures that connects smoothly the early growth to the asymptotic self-similar behaviour. Conclusions: The development of the Rayleigh-Taylor structures is affected, although not drastically, if the blast wave is dominated by cosmic rays. The amount of ejecta that makes it into the shocked interstellar medium is smaller in the latter case. If acceleration occurs at both shocks the extent of the Rayleigh-Taylor structures is similar but the reverse shock is strongly perturbed.Comment: 15 pages, 12 figures, accepted for publication in Astronomy and Astrophysics with minor editorial changes. Version with full resolution images can be found at http://www.lpl.arizona.edu/~ffrasche/~12692.pd

    Stability of a metallic state in the two-orbital Hubbard model

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    Electron correlations in the two-orbital Hubbard model at half-filling are investigated by combining dynamical mean field theory with the exact diagonalization method. We systematically study how the interplay of the intra- and inter-band Coulomb interactions, together with the Hund coupling, affects the metal-insulator transition. It is found that if the intra- and inter-band Coulomb interactions are nearly equal, the Fermi-liquid state is stabilized due to orbital fluctuations up to fairly large interactions, while the system is immediately driven to the Mott insulating phase away from this condition. The effects of the isotropic and anisotropic Hund coupling are also addressed.Comment: 7 pages, 9 figure
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