27,063 research outputs found

    A Randomized Trial Comparing Digital and Live Lecture Formats

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    Problem Statement and Background – Medical education is increasingly being conducted in community-based teaching sites making it difficult to provide a consistent curriculum. We conducted a randomized trial to assess whether digital lectures could replace live lectures. Methods – Students were randomized to either attending a lecture series at our main campus or viewing digital versions of the same lectures at community sites. Both groups completed an examination based on the lectures and the group viewing the digital lectures completed a feedback form. Results – The group who viewed the digital lectures performed slightly better than the live lecture group however the differences were not statistically significant. Despite technical problems the students who viewed the digital lectures overwhelmingly felt the digital lectures could replace live lectures. Conclusions – Digital lectures appear to be a viable alternative to live lectures as a means of delivering didactic presentations in a community-based setting

    Quadratic maps with a periodic critical point of period 2

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    We provide a complete classification of possible graphs of rational preperiodic points of endomorphisms of the projective line of degree 2 defined over the rationals with a rational periodic critical point of period 2, under the assumption that these maps have no periodic points of period at least 7. We explain how this extends results of Poonen on quadratic polynomials. We show that there are 13 possible graphs, and that such maps have at most 9 rational preperiodic points. We provide data related to the analogous classification of graphs of endomorphisms of degree 2 with a rational periodic critical point of period 3 or 4.Comment: Updated theorem 2 to rule out the cases of quadratic maps with a rational periodic critical point of period 2 and a rational periodic point of period 5 or

    Sources of Measurement Error in an ECG Examination: Implications for Performance-Based Assessments

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    Objective: To assess the sources of measurement error in an electrocardiogram (ECG) interpretation examination given in a third-year internal medicine clerkship. Design: Three successive generalizability studies were conducted. 1) Multiple faculty rated student responses to a previously administered exam. 2) The rating criteria were revised and study 1 was repeated. 3) The examination was converted into an extended matching format including multiple cases with the same underlying cardiac problem. Results: The discrepancies among raters (main effects and interactions) were dwarfed by the error associated with case specificity. The largest source of the differences among raters was in rating student errors of commission rather than student errors of omission. Revisions in the rating criteria may have helped increase inter-rater reliability slightly however, due to case specificity, it had little impact on the overall reliability of the exam. The third study indicated the majority of the variability in student performance across cases was in performance across cases within the same type of cardiac problem rather than between different types of cardiac problems. Conclusions: Case specificity was the overwhelming source of measurement error. The variation among cases came mainly from discrepancies in performance between examples of the same cardiac problem rather than from differences in performance across different types of cardiac problems. This suggests it is necessary to include a large number of cases even if the goal is to assess performance on only a few types of cardiac problems

    Experience, expertise and expert-performance research in public accounting

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    Bibliography: p. [22-25]

    A new look at the problem of gauge invariance in quantum field theory

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    Quantum field theory is assumed to be gauge invariant. However it is well known that when certain quantities are calculated using perturbation theory the results are not gauge invariant. The non-gauge invariant terms have to be removed in order to obtain a physically correct result. In this paper we will examine this problem and determine why a theory that is supposed to be gauge invariant produces non-gauge invariant results.Comment: Accepted by Physica Scripta. 27 page
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