89 research outputs found
Fusion rules and shrinking rules of topological orders in five dimensions
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 theories that
comprise the twisted topological terms of the 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 , we explore general
properties of all twisted terms in D. 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
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
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
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
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
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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