17 research outputs found

    Observation of Bound Surface States in Grain Boundary Junctions of High Temperature Superconductors

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    We have performed a detailed study of the tunneling spectra of bicrystal grain boundary junctions (GBJs) fabricated from the HTS YBCO, BSCCO, LSCO, and NCCO. In all experiments the tunneling direction was along the CuO planes. With the exception of NCCO, for all materials a pronounced zero bias conductance peak was observed which decreases with increasing temperature and disappears at the critical temperature. These results can be explained by the presence of a dominating d-wave symmetry of the order parameter resulting in the formation of zero energy Andreev bound states at surfaces and interfaces of HTS. The absence of a ZBCP for NCCO is consistent with a dominating s-wave symmetry of the pair potential in this material. The observed nonlinear shift of spectral weight to finite energies by applying a magnetic field is in qualitative agreement with recent theoretical predictions.Comment: 4 pages, 4 figures, to be published in Phys. Rev.

    Research on Teaching and Learning Mathematics at the Tertiary Level:State-of-the-art and Looking Ahead

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    This topical survey focuses on research in tertiary mathematics education, a field that has experienced considerable growth over the last 10 years. Drawing on the most recent journal publication as well as the latest advances from recent high quality conference proceedings, our review culls out the following five emergent areas of interest: mathematics teaching at the tertiary level; the role of mathematics in other disciplines; textbooks, assessment and students’ studying practices; transition to the tertiary level; and theoretical-methodological advances. We conclude the survey with a discussion of some potential ways forward for future research in this new and rapidly developing domain of inquiry

    Comparison of direct and indirect alcohol markers with PEth in blood and urine in alcohol dependent inpatients during detoxication.

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    The importance of direct and indirect alcohol markers to evaluate alcohol consumption in clinical and forensic settings is increasingly recognized. While some markers are used to prove abstinence from ethanol, other markers are suitable for detection of alcohol misuse. Phosphatidyl ethanol (PEth) is ranked among the latter. There is only little information about the correlation between PEth and other currently used markers (ethyl glucuronide, ethyl sulfate, carbohydrate deficient transferrin, gamma-glutamyl transpeptidase, and methanol) and about their decline during detoxification. To get more information, 18 alcohol-dependent patients in withdrawal therapy were monitored for these parameters in blood and urine for up to 19 days. There was no correlation between the different markers. PEth showed a rapid decrease at the beginning of the intervention, a slow decline after the first few days, and could still be detected after 19 days of abstinence from ethanol

    Neglected Outcomes of Customer Satisfaction

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    Although there is significant evidence that customer satisfaction is an important driver of firm profitability, extant literature has largely neglected two intermediate outcomes of customer satisfaction - a firm’s advertising and promotion efficiency and its human capital performance. Based on longitudinal analyses of large-scale secondary data from multiple sources, the authors find that customer satisfaction boosts the efficiency of future advertising and promotion investments. This finding can be explained by the possibility that customer satisfaction generates free word-of-mouth advertising and saves subsequent marketing costs. In addition, customer satisfaction has a positive influence on a company’s excellence in human capital (employee talent and manager superiority). This finding is highly novel, indicating that human resources managers should have a strong interest in customer satisfaction as well. Finally, the moderating influence of market concentration on both relationships is investigated. The uncovered results have important implications for marketers in their dialogue with financial executives and human resources managers

    Ontogeny, genetics, and cytology of Nicotiana hybrids

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