89 research outputs found

    Fusion rules and shrinking rules of topological orders in five dimensions

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    As a series of work about 5D (spacetime) topological orders, here we employ the path-integral formalism of 5D topological quantum field theory (TQFT) established in Zhang and Ye, JHEP 04 (2022) 138 to explore non-Abelian fusion rules, hierarchical shrinking rules and quantum dimensions of particle-like, loop-like and membrane-like topological excitations in 5D topological orders. To illustrate, we focus on a prototypical example of twisted BFBF theories that comprise the twisted topological terms of the BBABBA type. First, we classify topological excitations by establishing equivalence classes among all gauge-invariant Wilson operators. Then, we compute fusion rules from the path-integral and find that fusion rules may be of non-Abelian nature, i.e., the fusion outcome can be a direct sum of distinct excitations. We further compute shrinking rules. Especially, we discover exotic hierarchical structures hidden in shrinking processes of 5D or higher: a membrane is shrunk into particles and loops, and the loops are subsequently shrunk into a direct sum of particles. We obtain the algebraic structure of shrinking coefficients and fusion coefficients. We compute the quantum dimensions of all excitations and find that sphere-like membranes and torus-like membranes differ not only by their shapes but also by their quantum dimensions. We further study the algebraic structure that determines anomaly-free conditions on fusion coefficients and shrinking coefficients. Besides BBABBA, we explore general properties of all twisted terms in 55D. Together with braiding statistics reported before, the theoretical progress here paves the way toward characterizing and classifying topological orders in higher dimensions where topological excitations consist of both particles and spatially extended objects

    Algorithms used to identify ventricular arrhythmias and sudden cardiac death in retrospective studies: a systematic literature review

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    Drug-induced QT interval prolongation may increase the risk of sudden cardiac death or ventricular arrhythmias (SCD/VA), and therefore affects the safety profile of medications. Administrative databases can be used to inform pharmacoepidemiologic drug safety studies for such rare events. In order to compare event rates between studies, validated operational definitions of these events are needed. We conducted a systematic literature review in PubMed to identify algorithms for SCD/VA. Twenty-two studies were included in the review. Fifteen (68%) studies evaluated International Classification of Diseases, 9th revision (ICD-9) based medical data, of which six utilized a common, validated operational definition. This algorithm was based on principal hospitalization discharge diagnosis or first-listed emergency department visit diagnosis, with an average positive predictive value (PPV) of 85%. Four studies evaluated ICD-9 based death data, of which three utilized a common algorithm with an average PPV of 88%. Further validation of ICD, 10th revision algorithms are needed. In conclusion, we identified a validated algorithm for SCD/VA in medical data, as well as in death data. As such, to ensure comparability between new research and the existing literature, pharmacoepidemiologic research in this area should utilize common, validated algorithms, such as the ones identified in our review, to operationally define these events

    Algorithms used to identify ventricular arrhythmias and sudden cardiac death in retrospective studies: a systematic literature review

    Get PDF
    Drug-induced QT interval prolongation may increase the risk of sudden cardiac death or ventricular arrhythmias (SCD/VA), and therefore affects the safety profile of medications. Administrative databases can be used to inform pharmacoepidemiologic drug safety studies for such rare events. In order to compare event rates between studies, validated operational definitions of these events are needed. We conducted a systematic literature review in PubMed to identify algorithms for SCD/VA. Twenty-two studies were included in the review. Fifteen (68%) studies evaluated International Classification of Diseases, 9th revision (ICD-9) based medical data, of which six utilized a common, validated operational definition. This algorithm was based on principal hospitalization discharge diagnosis or first-listed emergency department visit diagnosis, with an average positive predictive value (PPV) of 85%. Four studies evaluated ICD-9 based death data, of which three utilized a common algorithm with an average PPV of 88%. Further validation of ICD, 10th revision algorithms are needed. In conclusion, we identified a validated algorithm for SCD/VA in medical data, as well as in death data. As such, to ensure comparability between new research and the existing literature, pharmacoepidemiologic research in this area should utilize common, validated algorithms, such as the ones identified in our review, to operationally define these events

    Faster VoxelPose: Real-time 3D Human Pose Estimation by Orthographic Projection

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    While the voxel-based methods have achieved promising results for multi-person 3D pose estimation from multi-cameras, they suffer from heavy computation burdens, especially for large scenes. We present Faster VoxelPose to address the challenge by re-projecting the feature volume to the three two-dimensional coordinate planes and estimating X, Y, Z coordinates from them separately. To that end, we first localize each person by a 3D bounding box by estimating a 2D box and its height based on the volume features projected to the xy-plane and z-axis, respectively. Then for each person, we estimate partial joint coordinates from the three coordinate planes separately which are then fused to obtain the final 3D pose. The method is free from costly 3D-CNNs and improves the speed of VoxelPose by ten times and meanwhile achieves competitive accuracy as the state-of-the-art methods, proving its potential in real-time applications.Comment: 22 pages, 7 figures, submitted to ECCV 202

    Relation between surface solitons and bulk solitons in nonlocal nonlinear media

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    We find that a surface soliton in nonlocal nonlinear media can be regarded as a half of a bulk soliton with an antisymmetric amplitude distribution. The analytical solutions for the surface solitons and breathers in strongly nonlocal media are obtained, and the critical power and breather period are gotten analytically and confirmed by numerical simulations. In addition, the oscillating propagation of nonlocal surface solitons launched away from the stationary position is considered as the interaction between the soliton and its out-of-phase image beam. Its trajectory and oscillating period obtained by our model are in good agreement with the numerical simulations.Comment: 12 pages, 8 figures, 39 reference, Accepted by Opt. Expres

    Evaluating Shanghai new towns' maturity of urban form : an exploration index based on new urban data

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    The natural evolution of urban forms over time is a key issue in urban morphology. With the rapid development of 7quantitative analytical tools and new urban data, new research potential has emerged. This study attempts to develop an analytical framework for evaluating the urban maturation process. Using street blocks as the analytical unit, this study integrates the spatial design network analysis (sDNA), Spacematrix, Points-of-Interests (POIs), and Open Street Map (OSM) in the geographical information system (GIS) to calculate the urban maturation index in the context of big data. Shanghai, a metropolitan city with a long urbanisation history and a series of new towns, was selected as the case study. The validation of this new index was first achieved by comparing this maturation index between several districts located in the city centre and suburban new towns. Insights in this direction would help generate new urban design guidance for creating vibrant urban places. This study also aimed to introduce new quantitative thinking into the previously qualitative and intuition-based fields of urban morphology and urban design
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