Hamiltonian particle-mesh simulations for a non-hydrostatic vertical slice model

2009 ◽  
pp. n/a-n/a
Author(s):  
Seoleun Shin ◽  
Sebastian Reich
Keyword(s):  
Vertical Slice

scholarly journals Analysis of relative abundances on environmental gradients

2018 ◽  
Author(s):  
Fiona Chong ◽  
Matthew Spencer
Keyword(s):  
Compositional Data ◽  
Environmental Gradients ◽  
Compositional Data Analysis ◽  
Depth Gradient ◽  
Negative Numbers ◽  
Marine Communities ◽  
Rates Of Change ◽  
Compositional Approach ◽  
Vertical Slice ◽  
Relative Abundances

Ecologists often analyze relative abundances, which are compositions (sets of non-negative numbers with a fixed sum). However, they have made surprisingly little use of recent advances in the field of compositional data analysis. Compositions form a vector space in which addition and scalar multiplication are replaced by operations known as perturbation and powering. This algebraic structure makes it easy to understand how relative abundances change along environmental gradients. We illustrate this with an analysis of changes in hard-substrate marine communities along a depth gradient. We show how the algebra of compositions can be used to understand patterns in dissimilarity. We use the calculus of simplex-valued functions to estimate rates of change, and to summarize the structure of the community over a vertical slice. We discuss the benefits of the compositional approach in the interpretation and visualization of relative abundance data.

Studying Up: Four Modalities, Two Challenges

2021 ◽  
Vol 3 (2) ◽  
pp. 232-252
Author(s):  
Hugh Gusterson
Keyword(s):  
Participant Observation ◽  
Institutional Review Boards ◽  
Critical Research ◽  
Critical Studies ◽  
Institutional Review ◽  
Vertical Slice ◽  
The Relationship ◽  
Review Boards ◽  
Studying Up

Abstract In her 1973 article “up the anthropologist” Laura Nader called on anthropologists to engage in critical studies of the relationship between powerful institutions and the broader society, using a “vertical slice” approach. But Nader worried that participant observation was hard in the context of studying up, and yet it has been presented as definitive of anthropology’s methodology. This article discusses four methodological strategies for studying up in the light of this concern: insider ethnography; covert ethnography; remote ethnography; and adapted participant observation. The first two have intellectual or ethical liabilities. The last is increasingly normalized. Going forward, anthropologists studying up face two obstacles: first, the increasingly totalizing hold of corporate and government workplaces over their employees, even when they are not at work; and, second, university institutional review boards (irb s) concerned to avoid conflictual or critical research.

Three-Dimensional Point Cloud Classification of Large Outdoor Scenes Based on Vertical Slice Sampling and Centroid Distance Histogram

2018 ◽  
Vol 45 (10) ◽  
pp. 1004001
Author(s):  
佟国峰 Tong Guofeng ◽  
杜宪策 Du Xiance ◽  
李勇 Li Yong ◽  
陈槐嵘 Chen Huairong ◽  
张庆春 Zhang Qingchun
Keyword(s):  
Point Cloud ◽  
Three Dimensional ◽  
Slice Sampling ◽  
Cloud Classification ◽  
Centroid Distance ◽  
Outdoor Scenes ◽  
Vertical Slice ◽  
Point Cloud Classification ◽  
Distance Histogram

Applications for Vertical-Slice Inversion

2020 ◽  
pp. 175-193
Author(s):  
Arata Kaneko ◽  
Xiao-Hua Zhu ◽  
Ju Lin
Keyword(s):  
Vertical Slice

scholarly journals Two-dimensional simulations of coronal rain dynamics

2020 ◽  
Vol 634 ◽  
pp. A36 ◽  
Author(s):  
D. Martínez-Gómez ◽  
R. Oliver ◽  
E. Khomenko ◽  
M. Collados
Keyword(s):  
Magnetic Field ◽  
Active Regions ◽  
Free Fall ◽  
Gaussian Profile ◽  
Horizontal Variation ◽  
Vertical Slice ◽  
Coronal Rain ◽  
Rain Events ◽  
Ideal Magnetohydrodynamic ◽  
The Magnetic Field

Context. Coronal rain often comes about as the final product of evaporation and condensation cycles that occur in active regions. Observations show that the condensed plasma falls with an acceleration that is less than that of free fall. Aims. We aim to improve the understanding of the physical mechanisms behind the slower than free-fall motion and the two-stage evolution (an initial phase of acceleration followed by an almost constant velocity phase) detected in coronal rain events. Methods. Using the MANCHA3D code, we solve the 2D ideal magnetohydrodynamic equations. We represent the solar corona as an isothermal vertically stratified atmosphere with a uniform vertical magnetic field. We represent the plasma condensation as a density enhancement described by a 2D Gaussian profile. We analyse the temporal evolution of the descending plasma and study its dependence on such parameters as density and magnetic field strength. Results. We confirm previous findings that indicate that the pressure gradient is the main force that opposes the action of gravity and slows down the blob descent, and that larger densities require larger pressure gradients to reach the constant speed phase. We find that the shape of a condensation with a horizontal variation of density is distorted during its fall because the denser parts of the blob fall faster than the lighter ones. This is explained by the fact that the duration of the initial acceleration phase and, therefore, the maximum falling speed attained by the plasma, increases with the ratio of blob to coronal density. We also find that the magnetic field plays a fundamental role in the evolution of the descending condensations. A strong enough magnetic field (greater than 10 G in our simulations) forces each plasma element to follow the path given by a particular field line, which allows for the description of the evolution of each vertical slice of the blob in terms of 1D dynamics, without the influence of the adjacent slices. In addition, under the typical conditions of the coronal rain events, the magnetic field prevents the development of Kelvin-Helmholtz instability.

scholarly journals Vertical slice modelling of nonlinear Eady waves using a compatible finite element method

2017 ◽  
Vol 343 ◽  
pp. 130-149 ◽  
Author(s):  
Hiroe Yamazaki ◽  
Jemma Shipton ◽  
Michael J.P. Cullen ◽  
Lawrence Mitchell ◽  
Colin J. Cotter
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Vertical Slice ◽  
Element Method

Inversion on a Vertical Slice

2020 ◽  
pp. 81-93
Author(s):  
Arata Kaneko ◽  
Xiao-Hua Zhu ◽  
Ju Lin
Keyword(s):  
Vertical Slice

The vertical slice transform on the unit sphere

2019 ◽  
Vol 22 (4) ◽  
pp. 899-917 ◽  
Author(s):  
Boris Rubin
Keyword(s):  
Unit Sphere ◽  
Radon Transform ◽  
Integral Geometry ◽  
Singular Value ◽  
Hypersingular Integrals ◽  
Inversion Formulas ◽  
Spherical Mean ◽  
Singular Value Decompositions ◽  
Vertical Slice ◽  
Class Of Functions

Abstract The vertical slice transform in spherical integral geometry takes a function on the unit sphere Sn to integrals of that function over spherical slices parallel to the last coordinate axis. This transform was investigated for n = 2 in connection with inverse problems of spherical tomography. The present article gives a survey of some methods which were originally developed for the Radon transform, hypersingular integrals, and the spherical mean Radon-like transforms, and can be adapted to obtain new inversion formulas and singular value decompositions for the vertical slice transform in the general case n ≥ 2 for a large class of functions.

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