scholarly journals Critical Scaling Laws of Dynamic Structure Functions for Type I Intermittent Chaos

1989 ◽  
Vol 82 (1) ◽  
pp. 1-6 ◽  
Author(s):  
T. Kobayashi ◽  
N. Mori ◽  
H. Hata ◽  
T. Horita ◽  
T. Yoshida ◽  
...  
Keyword(s):  
Scaling Laws ◽  
Dynamic Structure ◽  
Structure Functions ◽  
Type I ◽  
Critical Scaling ◽  
Intermittent Chaos

scholarly journals Scaling and Similarity of the Anisotropic Coherent Eddies in Near-Surface Atmospheric Turbulence

2018 ◽  
Vol 75 (3) ◽  
pp. 943-964 ◽  
Author(s):  
Khaled Ghannam ◽  
Gabriel G. Katul ◽  
Elie Bou-Zeid ◽  
Tobias Gerken ◽  
Marcelo Chamecki
Keyword(s):  
Scaling Laws ◽  
Velocity Structure ◽  
Scaling Law ◽  
Longitudinal Velocity ◽  
Structure Functions ◽  
Length Scale ◽  
Near Surface ◽  
Vegetation Canopies ◽  
Velocity Spectra ◽  
Attached Eddies

Abstract The low-wavenumber regime of the spectrum of turbulence commensurate with Townsend’s “attached” eddies is investigated here for the near-neutral atmospheric surface layer (ASL) and the roughness sublayer (RSL) above vegetation canopies. The central thesis corroborates the significance of the imbalance between local production and dissipation of turbulence kinetic energy (TKE) and canopy shear in challenging the classical distance-from-the-wall scaling of canonical turbulent boundary layers. Using five experimental datasets (two vegetation canopy RSL flows, two ASL flows, and one open-channel experiment), this paper explores (i) the existence of a low-wavenumber k−1 scaling law in the (wind) velocity spectra or, equivalently, a logarithmic scaling ln(r) in the velocity structure functions; (ii) phenomenological aspects of these anisotropic scales as a departure from homogeneous and isotropic scales; and (iii) the collapse of experimental data when plotted with different similarity coordinates. The results show that the extent of the k−1 and/or ln(r) scaling for the longitudinal velocity is shorter in the RSL above canopies than in the ASL because of smaller scale separation in the former. Conversely, these scaling laws are absent in the vertical velocity spectra except at large distances from the wall. The analysis reveals that the statistics of the velocity differences Δu and Δw approach a Gaussian-like behavior at large scales and that these eddies are responsible for momentum/energy production corroborated by large positive (negative) excursions in Δu accompanied by negative (positive) ones in Δw. A length scale based on TKE dissipation collapses the velocity structure functions at different heights better than the inertial length scale.

scholarly journals Solar wind low-frequency magnetohydrodynamic turbulence: extended self-similarity and scaling laws

1996 ◽  
Vol 3 (4) ◽  
pp. 247-261 ◽  
Author(s):  
V. Carbone ◽  
P. Veltri ◽  
R. Bruno
Keyword(s):  
Solar Wind ◽  
Scaling Laws ◽  
Velocity Structure ◽  
Fluid Flows ◽  
Structure Functions ◽  
Point Of View ◽  
Self Similarity ◽  
Extended Self ◽  
Scaling Exponents ◽  
Magnetohydrodynamic Turbulence

Abstract. In this paper we review some of the work done in investigating the scaling properties of Magnetohydrodynamic turbulence, by using velocity fluctuations measurements performed in the interplanetary space plasma by the Helios spacecraft. The set of scaling exponents ξq for the q-th order velocity structure functions, have been determined by using the Extended Self-Similarity hypothesis. We have found that the q-th order velocity structure function, when plotted vs. the 4-th order structure function, displays a range of self-similarity which extends over all the lengths covered by measurements, thus allowing for a very good determination of ξq. Moreover the results seem to show that the scaling exponents are the same regardless the various observation periods considered. The obtained scaling exponents have been compared with the results of some intermittency models for Kraichnan's turbulence, derived in the framework of infinitely divisible fragmentation processes, showing the good agreement between these models and our observations. Finally, on the basis of the actually available data sets, we show that scaling laws in Solar Wind turbulence seem to be different from turbulent scaling laws in the ordinary fluid flows. This is true for high-order velocity structure functions, while low-order velocity structure functions show the same scaling laws. Since our measurements involve length scales which extend over many order of magnitude where dissipation is practically absent, our results show that Solar Wind turbulence can be regarded as a testing bench for the investigation of general scaling behaviour in turbulent flows. In particular our results strongly support the point of view which attributes a key role to the inertial range dynamics in determining the intermittency characteristics in fluid flows, in contrast with the point of view which attributes intermittency to a finite Reynolds number effect.

scholarly journals Indoles from the commensal microbiota act via the AHR and IL-10 to tune the cellular composition of the colonic epithelium during aging

2020 ◽  
Vol 117 (35) ◽  
pp. 21519-21526 ◽  
Author(s):  
Domonica N. Powell ◽  
Alyson Swimm ◽  
Robert Sonowal ◽  
Alexis Bretin ◽  
Andrew T. Gewirtz ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
Goblet Cell ◽  
Intestinal Epithelium ◽  
Dynamic Structure ◽  
Goblet Cells ◽  
Type I ◽  
Cellular Composition ◽  
Type I Ifn ◽  
Commensal Microbiota ◽  
Goblet Cell Differentiation

The intestinal epithelium is a highly dynamic structure that rejuvenates in response to acute stressors and can undergo alterations in cellular composition as animals age. The microbiota, acting via secreted factors related to indole, appear to regulate the sensitivity of the epithelium to stressors and promote epithelial repair via IL-22 and type I IFN signaling. As animals age, the cellular composition of the intestinal epithelium changes, resulting in a decreased proportion of goblet cells in the colon. We show that colonization of young or geriatric mice with bacteria that secrete indoles and various derivatives or administration of the indole derivative indole-3 aldehyde increases proliferation of epithelial cells and promotes goblet cell differentiation, reversing an effect of aging. To induce goblet cell differentiation, indole acts via the xenobiotic aryl hydrocarbon receptor to increase expression of the cytokine IL-10. However, the effects of indoles on goblet cells do not depend on type I IFN or on IL-22 signaling, pathways responsible for protection against acute stressors. Thus, indoles derived from the commensal microbiota regulate intestinal homeostasis, especially during aging, via mechanisms distinct from those used during responses to acute stressors. Indoles may have utility as an intervention to limit the decline of barrier integrity and the resulting systemic inflammation that occurs with aging.

Fluctuations and Critical Scaling in Type-I Intermittency

1993 ◽  
Vol 21 (1) ◽  
pp. 7-12 ◽  
Author(s):  
A Rein ◽  
G Hüpper ◽  
E Schöll
Keyword(s):  
Type I ◽  
Critical Scaling

scholarly journals The q-Phase Transition and Critical Scaling Laws near the Band-Crisis Point of Chaotic Attractors

1989 ◽  
Vol 82 (5) ◽  
pp. 879-896 ◽  
Author(s):  
T. Yoshida ◽  
S. Miyazaki ◽  
H. Mori ◽  
T. Kobayashi ◽  
T. Horita ◽  
...  
Keyword(s):  
Phase Transition ◽  
Scaling Laws ◽  
Chaotic Attractors ◽  
Critical Scaling

scholarly journals Critical Analysis of Corneal Cross-linking (Part-II): Resolving the Controversial Issues (Theory versus Measurements)

2021 ◽  
pp. 23-34
Author(s):  
Jui-Teng Lin
Keyword(s):  
Light Intensity ◽  
Scaling Laws ◽  
Uv Light ◽  
Corneal Thickness ◽  
Cross Linking ◽  
Type I ◽  
Controversial Issues ◽  
Type Ii ◽  
Stromal Tissue ◽  
New Vision

Aims: To resolve the controversial issues of UV-light-initiated corneal collagen cross-linking (CXL) by theoretical formulas and measured clinical outcomes. Study Design:  Analysis and measured data of CXL. Place and Duration of Study: New Vision Inc, Taipei, between June 2021 and August 2021. Methodology: The controversial issues are addressed and resolved by analytical formulas including: the validation of Bunsen Roscoe law (BRL), the cutoff light intensity, the minimum corneal thickness, the demarcation line depth, the role of oxygen and riboflavin concentration. The overall CXL efficacy is governed by UV-A light intensity, dose, exposure time, mode of exposure (pulsed or CW), the riboflavin concentration, diffusion and drops pre-operation and interoperation administration, the concentration of oxygen in the stromal tissue (pre-op and inter-op), and environmental conditions. The length of the riboflavin presoaking time and viscosity of the riboflavin film also affect the crosslink depth. Analytic formulas are derived for the scaling laws for type-I and type-II efficacy, given by the square root of light intensity, and light dose, respectively. Conclusion: The controversial issues of CXL may be partially resolved via analytic formulas, and compared with measurements. The scaling laws of type-I and type-II efficacy are different and given by analytic formulas. Our formulas also predict the maximum light intensity and the minimum corneal thickness, which are consistent with measurements.

scholarly journals Phenomenologies of intermittent Hall MHD turbulence

2021 ◽  
Vol 0 (0) ◽  
pp. 0
Author(s):  
Mimi Dai
Keyword(s):  
Hall Effect ◽  
Scaling Laws ◽  
Structure Functions ◽  
Energy Spectra ◽  
Mhd Turbulence ◽  
Hall Mhd

<p style='text-indent:20px;'>We introduce the concept of intermittency dimension for the magnetohydrodynamics (MHD) to quantify the intermittency effect. With dependence on the intermittency dimension, we derive phenomenological laws for intermittent MHD turbulence with and without the Hall effect. In particular, scaling laws of dissipation wavenumber, energy spectra and structure functions are predicted. Moreover, we are able to provide estimates for energy spectra and structure functions which are consistent with the predicted scalings.</p>

scholarly journals High type I collagen density fails to increase breast cancer stem cell phenotype

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9153
Author(s):  
Iuri C. Valadão ◽  
Ana Carolina L. Ralph ◽  
François Bordeleau ◽  
Luciana M. Dzik ◽  
Karen S.C. Borbely ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Stem Cell ◽  
Cancer Stem Cell ◽  
Type I Collagen ◽  
Dynamic Structure ◽  
Metastatic Potential ◽  
Breast Cancer Stem Cell ◽  
Cell Phenotype ◽  
Type I ◽  
Mcf 7

Breast cancer is a highly frequent and lethal malignancy which metastasis and relapse frequently associates with the existence of breast cancer stem cells (CSCs). CSCs are undifferentiated, aggressive and highly resistant to therapy, with traits modulated by microenvironmental cells and the extracellular matrix (ECM), a biologically complex and dynamic structure composed mainly by type I collagen (Col-I). Col-I enrichment in the tumor-associated ECM leads to microenvironment stiffness and higher tumor aggressiveness and metastatic potential. While Col-I is also known to induce tumor stemness, it is unknown if such effect is dependent of Col-I density. To answer this question, we evaluated the stemness phenotype of MDA-MB-231 and MCF-7 human breast cancer cells cultured within gels of varying Col-I densities. High Col-I density increased CD44+CD24− breast cancer stem cell (BCSC) immunophenotype but failed to potentiate Col-I fiber alignment, cell self-renewal and clonogenicity in MDA-MB-231 cells. In MCF-7 cells, high Col-I density decreased total levels of variant CD44 (CD44v). Common to both cell types, high Col-I density induced neither markers related to CSC nor those related with mechanically-induced cell response. We conclude that high Col-I density per se is not sufficient to fully develop the BCSC phenotype.

Sine-Gordon kinks in dynamic structure functions

1985 ◽  
Vol 32 (11) ◽  
pp. 7308-7314 ◽  
Author(s):  
C. L. Hammer ◽  
J. Ely Shrauner
Keyword(s):  
Dynamic Structure ◽  
Structure Functions
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