scholarly journals Fluid Energy Cascade Rate and Kinetic Damping: New Insight from 3D Landau-fluid Simulations

2021 ◽  
Vol 923 (1) ◽  
pp. 122
Author(s):  
R. Ferrand ◽  
F. Sahraoui ◽  
D. Laveder ◽  
T. Passot ◽  
P. L. Sulem ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Three Dimensional ◽  
Theoretical Description ◽  
Energy Cascade ◽  
Landau Damping ◽  
Magnetized Plasmas ◽  
Fluid Models ◽  
Small Scales

Abstract Using an exact law for incompressible Hall magnetohydrodynamics (HMHD) turbulence, the energy cascade rate is computed from three-dimensional HMHD-CGL (biadiabatic ions and isothermal electrons) and Landau-fluid numerical simulations that feature different intensities of Landau damping over a broad range of wavenumbers, typically 0.05 ≲ k ⊥ d i ≲ 100. Using three sets of cross-scale simulations where turbulence is initiated at large, medium, and small scales, the ability of the fluid energy cascade to “sense” the kinetic Landau damping at different scales is tested. The cascade rate estimated from the exact law and the dissipation calculated directly from the simulation are shown to reflect the role of Landau damping in dissipating energy at all scales, with an emphasis on the kinetic ones. This result provides new prospects on using exact laws for simplified fluid models to analyze dissipation in kinetic simulations and spacecraft observations, and new insights into theoretical description of collisionless magnetized plasmas.

scholarly journals Numerical simulations of Hall MHD small-scale dynamos

2009 ◽  
Vol 5 (H15) ◽  
pp. 436-437
Author(s):  
Daniel O. Gómez ◽  
Pablo D. Mininni ◽  
Pablo Dmitruk
Keyword(s):  
Numerical Simulations ◽  
Hall Effect ◽  
Three Dimensional ◽  
Theoretical Framework ◽  
Mhd Equations ◽  
Small Scale ◽  
Hall Parameter ◽  
Hall Mhd ◽  
Three Dimensional Simulations

AbstractMuch of the progress in our understanding of dynamo mechanisms, has been made within the theoretical framework of magnetohydrodynamics (MHD). However, for sufficiently diffuse media, the Hall effect eventually becomes non-negligible. We present results from three dimensional simulations of the Hall-MHD equations subjected to random non-helical forcing. We study the role of the Hall effect in the dynamo efficiency for different values of the Hall parameter, using a pseudospectral code to achieve exponentially fast convergence.

scholarly journals Energy cascade rate in isothermal compressible magnetohydrodynamic turbulence

2018 ◽  
Vol 84 (4) ◽  
Author(s):  
N. Andrés ◽  
F. Sahraoui ◽  
S. Galtier ◽  
L. Z. Hadid ◽  
P. Dmitruk ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Rotation Group ◽  
Energy Cascade ◽  
Relative Importance ◽  
Dominant Contribution ◽  
Magnetohydrodynamic Turbulence ◽  
Guide Field ◽  
Small Scales ◽  
Spurious Results

Three-dimensional direct numerical simulations are used to study the energy cascade rate in isothermal compressible magnetohydrodynamic turbulence. Our analysis is guided by a two-point exact law derived recently for this problem in which flux, source, hybrid and mixed terms are present. The relative importance of each term is studied for different initial subsonic Mach numbers$M_{S}$and different magnetic guide fields$\boldsymbol{B}_{0}$. The dominant contribution to the energy cascade rate comes from the compressible flux, which depends weakly on the magnetic guide field$\boldsymbol{B}_{0}$, unlike the other terms whose moduli increase significantly with$M_{S}$and$\boldsymbol{B}_{0}$. In particular, for strong$\boldsymbol{B}_{0}$the source and hybrid terms are dominant at small scales with almost the same amplitude but with a different sign. A statistical analysis undertaken with an isotropic decomposition based on the SO(3) rotation group is shown to generate spurious results in the presence of$\boldsymbol{B}_{0}$, when compared with an axisymmetric decomposition better suited to the geometry of the problem. Our numerical results are compared with previous analyses made within situmeasurements in the solar wind and the terrestrial magnetosheath.

The Role of Three-Dimensional Imaging in Evaluation of the Sinonasal Mass

1996 ◽  
Vol 34 (1) ◽  
pp. 27
Author(s):  
Sue Yon Shim ◽  
Ki Joon Sung ◽  
Young Ju Kim ◽  
In Soo Hong ◽  
Myung Soon Kim ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Three Dimensional Imaging ◽  
Sinonasal Mass

Homogenization and Mass Identity vs. Individual Identity. An Analysis in the Light of the Theory of “The Three Dimensional Spiral of Sense

2016 ◽  
Vol 2 (2) ◽  
pp. 40
Author(s):  
Miriam Aparicio
Keyword(s):  
Three Dimensional ◽  
Individual Identity ◽  
Cognitive Effects ◽  
The Media

This study tests some hypotheses included in the psycho-social-communicational paradigm, which emphasizes the cognitive effects of the media and the role of the psychosocial subject as the recipient

Dysregulation of HOX as a Potential Therapeutic Target in Breast Cancer

2020 ◽  
Vol 27 ◽  
Author(s):  
Ji-Yeon Lee ◽  
Myoung Hee Kim
Keyword(s):  
Breast Cancer ◽  
Hox Genes ◽  
Therapeutic Potential ◽  
Expression Patterns ◽  
Genome Structure ◽  
Control Cell ◽  
Three Dimensional ◽  
Cellular Processes ◽  
Hox Protein

: HOX genes belong to the highly conserved homeobox superfamily, responsible for the regulation of various cellular processes that control cell homeostasis, from embryogenesis to carcinogenesis. The abnormal expression of HOX genes is observed in various cancers, including breast cancer; they act as oncogenes or as suppressors of cancer, according to context. In this review, we analyze HOX gene expression patterns in breast cancer and examine their relationship, based on the three-dimensional genome structure of the HOX locus. The presence of non-coding RNAs, embedded within the HOX cluster, and the role of these molecules in breast cancer have been reviewed. We further evaluate the characteristic activity of HOX protein in breast cancer and its therapeutic potential.

Central ossifying fibroma of mandible

2020 ◽  
Vol 13 (12) ◽  
pp. e239286
Author(s):  
Kumar Nilesh ◽  
Prashant Punde ◽  
Nitin Shivajirao Patil ◽  
Amol Gautam
Keyword(s):  
Fibrous Tissue ◽  
Three Dimensional ◽  
Facial Asymmetry ◽  
Ossifying Fibroma ◽  
Mandible Reconstruction ◽  
Three Dimensional Printing ◽  
Osseous Lesion ◽  
Large Size ◽  
Dimensional Printing

Ossifying fibroma (OF) is a rare, benign, fibro-osseous lesion of the jawbone characterised by replacement of the normal bone with fibrous tissue. The fibrous tissue shows varying amount of calcified structures resembling bone and/or cementum. The central variant of OF is rare, and shows predilection for mandible among the jawbone. Although it is classified as fibro-osseous lesion, it clinically behaves as a benign tumour and can grow to large size, causing bony swelling and facial asymmetry. This paper reports a case of large central OF of mandible in a 40-year-old male patient. The lesion was treated by segmental resection of mandible. Reconstruction of the surgical defect was done using avascular fibula bone graft. Role of three-dimensional printing of jaw and its benefits in surgical planning and reconstruction are also highlighted.

scholarly journals Charge algebra in Al(A)dSn spacetimes

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Adrien Fiorucci ◽  
Romain Ruzziconi
Keyword(s):  
Boundary Conditions ◽  
Dirichlet Boundary ◽  
Three Dimensional ◽  
Dirichlet Boundary Conditions ◽  
Boundary Structure ◽  
Asymptotic Symmetry ◽  
Renormalization Procedure ◽  
Field Dependent ◽  
Odd Dimensions

Abstract The gravitational charge algebra of generic asymptotically locally (A)dS spacetimes is derived in n dimensions. The analysis is performed in the Starobinsky/Fefferman-Graham gauge, without assuming any further boundary condition than the minimal falloffs for conformal compactification. In particular, the boundary structure is allowed to fluctuate and plays the role of source yielding some symplectic flux at the boundary. Using the holographic renormalization procedure, the divergences are removed from the symplectic structure, which leads to finite expressions. The charges associated with boundary diffeomorphisms are generically non-vanishing, non-integrable and not conserved, while those associated with boundary Weyl rescalings are non-vanishing only in odd dimensions due to the presence of Weyl anomalies in the dual theory. The charge algebra exhibits a field-dependent 2-cocycle in odd dimensions. When the general framework is restricted to three-dimensional asymptotically AdS spacetimes with Dirichlet boundary conditions, the 2-cocycle reduces to the Brown-Henneaux central extension. The analysis is also specified to leaky boundary conditions in asymptotically locally (A)dS spacetimes that lead to the Λ-BMS asymptotic symmetry group. In the flat limit, the latter contracts into the BMS group in n dimensions.

scholarly journals Learning by Doing: The Use of Distance, Corners and Length in Rewarded Geometric Tasks by Zebrafish (Danio rerio)

Animals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 2001
Author(s):  
Greta Baratti ◽  
Angelo Rizzo ◽  
Maria Elena Miletto Petrazzini ◽  
Valeria Anna Sovrano
Keyword(s):  
Danio Rerio ◽  
Three Dimensional ◽  
Reference Memory ◽  
Spatial Abilities ◽  
Learning By Doing ◽  
Surface Distance ◽  
Extended Surfaces ◽  
Unequal Length ◽  
Over Time

Zebrafish spontaneously use distance and directional relationships among three-dimensional extended surfaces to reorient within a rectangular arena. However, they fail to take advantage of either an array of freestanding corners or an array of unequal-length surfaces to search for a no-longer-present goal under a spontaneous cued memory procedure, being unable to use the information supplied by corners and length without some kind of rewarded training. The present study aimed to tease apart the geometric components characterizing a rectangular enclosure under a procedure recruiting the reference memory, thus training zebrafish in fragmented layouts that provided differences in surface distance, corners, and length. Results showed that fish, besides the distance, easily learned to use both corners and length if subjected to a rewarded exit task over time, suggesting that they can represent all the geometrically informative parts of a rectangular arena when consistently exposed to them. Altogether, these findings highlight crucially important issues apropos the employment of different behavioral protocols (spontaneous choice versus training over time) to assess spatial abilities of zebrafish, further paving the way to deepen the role of visual and nonvisual encodings of isolated geometric components in relation to macrostructural boundaries.

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