730 research outputs found

    Algebraic Properties of Riemannian Manifolds

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    Algebraic properties are explored for the curvature tensors of Riemannian manifolds, using the irreducible decomposition of curvature tensors. Our method provides a powerful tool to analyze the irreducible basis as well as an algorithm to determine the linear dependence of arbitrary Riemann polynomials. We completely specify 13 independent basis elements for the quartic scalars and explicitly find 13 linear relations among 26 scalar invariants. Our method provides several completely new results, including some clues to identify 23 independent basis elements from 90 quintic scalars, that are difficult to find otherwise.Comment: A few typos corrected; 40 pages (4 appendices: 16 pages). To appear in General Relativity and Gravitatio

    Effects of Hawthorn on the Progression of Heart Failure in a Rat Model of Aortic Constriction

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90301/1/phco.29.6.639.pd

    Benthic invertebrate fauna in the islets of Namuseom and Bukhyeongjeseom off Busan

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    AbstractThis study was conducted to examine the benthic invertebrate fauna inhabiting in the subtidal zone in and around the islets of Namuseom and Bukhyeongjeseom off the coast of Busan by SCUBA diving in September 2013. As a consequence, it was confirmed that a total of 6 phyla, 14 classes, 20 orders, 46 families, and 73 species of zoobenthos inhabit in and around those islets. The total number of species surveyed by taxon during the study is 22 species of Arthropoda (30%), 20 species of Mollusca (27%), 15 species of Cnidaria (21%), 10 species of Echinodermata (14%), four species of Poridera (5%), and two species of Chordata

    Successful removal of kinked J-guide wire under fluoroscopic guidance during central venous catheterization -A case report-

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    Guidewire-associated complications that occur during the process of central venous catheterization include its kinking, looping, knotting and breakage. The removal of a looped or knotted guidewire is problematic because it can cause vessel damage, major hemorrhage, or embolization of a fractured guidewire. We report a case of guidewire kinking and its successful removal under fluoroscopic guidance

    Serum BDNF levels in patients with gambling disorder are associated with the severity of gambling disorder and Iowa Gambling Task indices

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    Background and aims Gambling disorder (GD) shares many similarities with substance use disorders (SUDs) in clinical, neurobiological, and neurocognitive features, including decision-making. We evaluated the relationships among, GD, decision-making, and brain-derived neurotrophic factor (BDNF), as measured by serum BDNF levels. Methods Twenty-one male patients with GD and 21 healthy sex- and age-matched control subjects were evaluated for associations between serum BDNF levels and the Problem Gambling Severity Index (PGSI), as well as between serum BDNF levels and Iowa Gambling Task (IGT) indices. Results The mean serum BDNF levels were significantly increased in patients with GD compared to healthy controls. A significant correlation between serum BDNF levels and PGSI scores was found when controlling for age, depression, and duration of GD. A significant negative correlation was obtained between serum BDNF levels and IGT improvement scores. Discussion These findings support the hypothesis that serum BDNF levels constitute a dual biomarker for the neuroendocrine changes and the severity of GD in patients. Serum BDNF level may serve as an indicator of poor decision-making performance and learning processes in GD and help to identify the common physiological underpinnings between GD and SUDs
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