10,069 research outputs found

    From Schritte and Wechsel to Coxeter Groups

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    The PLR-moves of neo-Riemannian theory, when considered as reflections on the edges of an equilateral triangle, define the Coxeter group S~3\widetilde S_3. The elements are in a natural one-to-one correspondence with the triangles in the infinite Tonnetz. The left action of S~3\widetilde S_3 on the Tonnetz gives rise to interesting chord sequences. We compare the system of transformations in S~3\widetilde S_3 with the system of Schritte and Wechsel introduced by Hugo Riemann in 1880. Finally, we consider the point reflection group as it captures well the transition from Riemann's infinite Tonnetz to the finite Tonnetz of neo-Riemannian theory.Comment: 14 pages for the Mathematics and Computation in Music Conference in June 2019 in Madrid, the revised version extends the music theoretic discussio

    Standing on the Shoulders of Giants: The Cleft Palate-Craniofacial Journal (1964-1989)Electronic Archive

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    Current research and clinical practice in cleft palate and craniofacial disorders “stands on the shoulders of giants” who came before us. To enable thirty years of seminal research articles to become digitally available to a worldwide community of students, scholars, and clinicians, a collaboration was forged in 2004 between University of Pittsburgh’s Digital Research Library (DRL) and ACPA, (with the agreement of Allen Press), to create an electronic archive of the first thirty years of the Cleft Palate Craniofacial Journal . The work was performed pro bono, by all parties

    Several new catalysts for reduction of oxygen in fuel cells

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    Test results prove nickel carbide or nitride, nickel-cobalt carbide, titanium carbide or nitride, and intermetallic compounds of the transition or noble metals to be efficient electrocatalysts for oxygen reduction in alkaline electrolytes in low temperature fuel cells

    Acute complete heart block in dogs

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    A study has been conducted immediately and up to 18 days after the surgical production of complete heart block in dogs. Immediately after surgery cardiac output, coronary flow, and mean arterial pressure were reduced in rough proportion to the degree of bradycardia. In time, these measures began to return toward preoperative levels. Paralleling the diminished left ventricular work was a diminished left ventricular oxygen consumption with little consequent change in myocardial efficiency. Small rises were detected in central venous pressure. At autopsy, the only unequivocal abnormality was myocardial hypertrophy which became measurable between 2 and 18 days after operation

    Comparison of fluorescence-based techniques for the quantification of particle-induced hydroxyl radicals

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    <p>Abstract</p> <p>Background</p> <p>Reactive oxygen species including hydroxyl radicals can cause oxidative stress and mutations. Inhaled particulate matter can trigger formation of hydroxyl radicals, which have been implicated as one of the causes of particulate-induced lung disease. The extreme reactivity of hydroxyl radicals presents challenges to their detection and quantification. Here, three fluorescein derivatives [aminophenyl fluorescamine (APF), amplex ultrared, and dichlorofluorescein (DCFH)] and two radical species, proxyl fluorescamine and tempo-9-ac have been compared for their usefulness to measure hydroxyl radicals generated in two different systems: a solution containing ferrous iron and a suspension of pyrite particles.</p> <p>Results</p> <p>APF, amplex ultrared, and DCFH react similarly to the presence of hydroxyl radicals. Proxyl fluorescamine and tempo-9-ac do not react with hydroxyl radicals directly, which reduces their sensitivity. Since both DCFH and amplex ultrared will react with reactive oxygen species other than hydroxyl radicals and another highly reactive species, peroxynitite, they lack specificity.</p> <p>Conclusion</p> <p>The most useful probe evaluated here for hydroxyl radicals formed from cell-free particle suspensions is APF due to its sensitivity and selectivity.</p

    Ground states and formal duality relations in the Gaussian core model

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    We study dimensional trends in ground states for soft-matter systems. Specifically, using a high-dimensional version of Parrinello-Rahman dynamics, we investigate the behavior of the Gaussian core model in up to eight dimensions. The results include unexpected geometric structures, with surprising anisotropy as well as formal duality relations. These duality relations suggest that the Gaussian core model possesses unexplored symmetries, and they have implications for a broad range of soft-core potentials.Comment: 7 pages, 1 figure, appeared in Physical Review E (http://pre.aps.org

    Overview: Computer vision and machine learning for microstructural characterization and analysis

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    The characterization and analysis of microstructure is the foundation of microstructural science, connecting the materials structure to its composition, process history, and properties. Microstructural quantification traditionally involves a human deciding a priori what to measure and then devising a purpose-built method for doing so. However, recent advances in data science, including computer vision (CV) and machine learning (ML) offer new approaches to extracting information from microstructural images. This overview surveys CV approaches to numerically encode the visual information contained in a microstructural image, which then provides input to supervised or unsupervised ML algorithms that find associations and trends in the high-dimensional image representation. CV/ML systems for microstructural characterization and analysis span the taxonomy of image analysis tasks, including image classification, semantic segmentation, object detection, and instance segmentation. These tools enable new approaches to microstructural analysis, including the development of new, rich visual metrics and the discovery of processing-microstructure-property relationships.Comment: submitted to Materials and Metallurgical Transactions

    Cross-correlating the Thermal Sunyaev-Zel'dovich Effect and the Distribution of Galaxy Clusters

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    We present the analytical formulas, derived based on the halo model, to compute the cross-correlation between the thermal Sunyaev-Zel'dovich (SZ) effect and the distribution of galaxy clusters. By binning the clusters according to their redshifts and masses, this cross-correlation, the so-called stacked SZ signal, reveals the average SZ profile around the clusters. The stacked SZ signal is obtainable from a joint analysis of an arcminute-resolution cosmic microwave background (CMB) experiment and an overlapping optical survey, which allows for detection of the SZ signals for clusters whose masses are below the individual cluster detection threshold. We derive the error covariance matrix for measuring the stacked SZ signal, and then forecast for its detection from ongoing and forthcoming combined CMB-optical surveys. We find that, over a wide range of mass and redshift, the stacked SZ signal can be detected with a significant signal to noise ratio (total S/N \gsim 10), whose value peaks for the clusters with intermediate masses and redshifts. Our calculation also shows that the stacking method allows for probing the clusters' SZ profiles over a wide range of scales, even out to projected radii as large as the virial radius, thereby providing a promising way to study gas physics at the outskirts of galaxy clusters.Comment: 11 pages, 6 figures, 3 tables, minor revisions reflect PRD published versio

    Pattern densities in fluid dimer models

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    In this paper, we introduce a family of observables for the dimer model on a bi-periodic bipartite planar graph, called pattern density fields. We study the scaling limit of these objects for liquid and gaseous Gibbs measures of the dimer model, and prove that they converge to a linear combination of a derivative of the Gaussian massless free field and an independent white noise.Comment: 38 pages, 3 figure

    An improved robot for bridge inspection

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    This paper presents a significant improvement from the previous submission from the same authors at ISARC 2016. The robot is now equipped with low-cost cameras and a 2D laser scanner which is used to monitor and survey a bridge bearing. The robot is capable of localising by combining a data from a pre-surveyed 3D model of the space with real-time data collection in-situ. Autonomous navigation is also performed using the 2D laser scanner in a mapped environment. The Robot Operating System (ROS) framework is used to integrate data collection and communication for navigation
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