85 research outputs found

    On the complete classification of the unitary N=2 minimal superconformal field theories

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    Aiming at a complete classification of unitary N=2 minimal models (where the assumption of space-time supersymmetry has been dropped), it is shown that each modular invariant candidate of a partition function for such a theory is indeed the partition function of a minimal model. A family of models constructed via orbifoldings of either the diagonal model or of the space-time supersymmetric exceptional models demonstrates that there exists a unitary N=2 minimal model for every one of the allowed partition functions in the list obtained from Gannon's work. Kreuzer and Schellekens' conjecture that all simple current invariants can be obtained as orbifolds of the diagonal model, even when the extra assumption of higher-genus modular invariance is dropped, is confirmed in the case of the unitary N=2 minimal models by simple counting arguments.Comment: 53 pages; Latex; minor changes in v2: intro expanded, references added, typos corrected, footnote added on p31; renumbering of sections; main theorem reformulated for clarity, but contents unchanged. Minor revisions in v3: typos corrected, footnotes 5, 6 added, lemma 1 and section 3.3.2 rewritten for greater generality, section 3.3 review removed. To appear in Comm. Math. Phy

    Cost calculation and prediction in adult intensive care: A ground-up utilization study

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    Publisher's copy made available with the permission of the publisherThe ability of various proxy cost measures, including therapeutic activity scores (TISS and Omega) and cumulative daily severity of illness scores, to predict individual ICU patient costs was assessed in a prospective “ground-up” utilization costing study over a six month period in 1991. Daily activity (TISS and Omega scores) and utilization in consecutive admissions to three adult university associated ICUs was recorded by dedicated data collectors. Cost prediction used linear regression with determination (80%) and validation (20%) data sets. The cohort, 1333 patients, had a mean (SD) age 57.5 (19.4) years, (41% female) and admission APACHE III score of 58 (27). ICU length of stay and mortality were 3.9 (6.1) days and 17.6% respectively. Mean total TISS and Omega scores were 117 (157) and 72 (113) respectively. Mean patient costs per ICU episode (1991 AUS)wereAUS) were 6801 (10311),withmediancostsof10311), with median costs of 2534, range 106to106 to 95,602. Dominant cost fractions were nursing 43.3% and overheads 16.9%. Inflation adjusted year 2002 (mean) costs were 9343(9343 ( AUS). Total costs in survivors were predicted by Omega score, summed APACHE III score and ICU length of stay; determination R2, 0.91; validation 0.88. Omega was the preferred activity score. Without the Omega score, predictors were age, summed APACHE III score and ICU length of stay; determination R2, 0.73; validation 0.73. In non-survivors, predictors were age and ICU length of stay (plus interaction), and Omega score (determination R2, 0.97; validation 0.91). Patient costs may be predicted by a combination of ICU activity indices and severity scores.J. L. Moran, A. R. Peisach, P. J. Solomon, J. Martinhttp://www.aaic.net.au/Article.asp?D=200403

    New Strong-Field QED Effects at ELI: Nonperturbative Vacuum Pair Production

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    Since the work of Sauter, and Heisenberg, Euler and K\"ockel, it has been understood that vacuum polarization effects in quantum electrodynamics (QED) predict remarkable new phenomena such as light-light scattering and pair production from vacuum. However, these fundamental effects are difficult to probe experimentally because they are very weak, and they are difficult to analyze theoretically because they are highly nonlinear and/or nonperturbative. The Extreme Light Infrastructure (ELI) project offers the possibility of a new window into this largely unexplored world. I review these ideas, along with some new results, explaining why quantum field theorists are so interested in this rapidly developing field of laser science. I concentrate on the theoretical tools that have been developed to analyze nonperturbative vacuum pair production.Comment: 20 pages, 9 figures; Key Lecture at the ELI Workshop and School on "Fundamental Physics with Ultra-High Fields", 29 Sept - 2 Oct. 2008, Frauenworth Monastery, Germany; v2: refs updated, English translations of reviews of Nikishov and Ritu

    The Physics of the B Factories

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    The Role of Gait Analysis in the Evaluation of Patients with Cervical Myelopathy: A Literature Review Study

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    Background Gait analysis represents one of the newest methodologies used in the clinical evaluation of patients with cervical myelopathy (CM). Objective To describe the role of gait analysis in the clinical evaluation of patients with CM, as well as its potential role in the evaluation of the functional outcome of any surgical intervention. Methods A literature review was performed in the PubMed, OVID, and Google Scholar medical databases, from January 1995 to August 2016, using the terms “analysis,” “anterior,” “cervical myelopathy,” “gait,” “posterior,” and “surgery.” Clinical series comparing the gait patterns of patients with CM with healthy controls, as well as series evaluating gait and walk changes before and after surgical decompression, were reviewed. Case studies were excluded. Results Nine prospective and 3 retrospective studies were found. Most of the retrieved studies showed the presence of characteristic, abnormal gait patterns among patients with CM, consisting of decreased gait speed, cadence, step length, stride length, and single-limb support time. In addition, patients with CM routinely present increased step and stride time, double-limb support time, and step width, and they have altered knee and ankle joint range of motion, compared with healthy controls. Moreover, gait and walk analysis may provide accurate functional assessment of the functional outcome of patients with CM undergoing surgical decompression. Conclusions Gait analysis may well be a valuable and objective tool along with other parameters in the evaluation of functionality in patients with CM, as well as in the assessment of the outcome of any surgical intervention in these patients. © 2017 Elsevier Inc
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