scholarly journals Spatio-temporal Investigations of the Incomplete Spin Transition in a Single Crystal of [Fe(2-pytrz)2{Pt(CN)4}]·3H2O: Experiment and Theory

Crystals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 46 ◽  
Author(s):  
Houcem Fourati ◽  
Guillaume Bouchez ◽  
Miguel Paez-Espejo ◽  
Smail Triki ◽  
Kamel Boukheddaden
Keyword(s):  
Single Crystal ◽  
High Spin ◽  
Small Volume ◽  
Spin Transition ◽  
Reaction Diffusion ◽  
Microscopy Technique ◽  
Temporal Properties ◽  
Reaction Diffusion Model ◽  
Spatio Temporal ◽  
Anisotropic Reaction Diffusion

Optical microscopy technique is used to investigate the thermal and the spatio-temporal properties of the spin-crossover single crystal [Fe(2-pytrz) 2 {Pt(CN) 4 }]·3H 2 O, which exhibits a first-order spin transition from a full high-spin (HS) state at high temperature to an intermediate, high-spin low-spin (HS-LS) state, below 153 K, where only one of the two crystallographic Fe(II) centers switches from the HS to HS-LS state. In comparison with crystals undergoing a complete spin transition, the present transformation involves smaller volume changes at the transition, which helps to preserving the crystal’s integrity. By analyzing the spatio-temporal properties of this spin transition, we evidenced a direct correlation between the orientation and shape of HS/HS-LS domain wall with the crystal’s shape. Thanks to the small volume change accompanying this spin transition, the analysis of the experimental data by an anisotropic reaction-diffusion model becomes very relevant and leads to an excellent agreement with the experimental observations.

scholarly journals Simulating Dengue: Comparison of Observed and Predicted Cases from Generic Reaction-Diffusion Model for Transmission of Mosquito-Borne Diseases

MATEMATIKA ◽  
2019 ◽  
Vol 35 (3) ◽  
Author(s):  
Cynthia Mui Lian Kon ◽  
Jane Labadin
Keyword(s):  
Diffusion Model ◽  
Recovery Rate ◽  
Urban Areas ◽  
Reaction Diffusion ◽  
Severe Dengue ◽  
Generic Model ◽  
Reaction Diffusion Model ◽  
Temporal Model ◽  
Spatio Temporal ◽  
Actual Prevalence

Dengue is a mosquito-borne disease caused by virus and found mostly in urban and semi-urban areas, in many regions of the world. Female Aedes mosquitoes, which usually bite during daytime, spread the disease. This flu-like disease may progress to severe dengue and cause fatality. A generic reaction-diffusion model for transmission of mosquito-borne diseases was proposed and formulated. The motivation is to explore the ability of the generic model to reproduce observed dengue cases in Borneo, Malaysia. Dengue prevalence in four districts in Borneo namely Kuching, Sibu, Bintulu and Miri are compared with simulations results obtained from the temporal and spatio-temporal generic model respectively. Random diffusion of human and mosquito populations are taken into account in the spatio-temporal model. It is found that temporal simulations closely resemble the general behavior of actual prevalence in the three locations except for Bintulu. The recovery rate in Bintulu district is found to be the lowest among the districts, suggesting a different dengue serotype may be present. From observation, the temporal generic model underestimates the recovery rate in comparison to the spatio-temporal generic model.

scholarly journals Spatio-temporal Brusselator Model and Biological Pattern Formation

2021 ◽  
pp. 88-99
Author(s):  
Zakir Hossine ◽  
Oishi Khanam ◽  
Md. Mashih Ibn Yasin Adan ◽  
Md. Kamrujjaman
Keyword(s):  
Pattern Formation ◽  
Diffusion Model ◽  
Initial Conditions ◽  
Neumann Boundary ◽  
Reaction Diffusion ◽  
Two Dimensions ◽  
Brusselator Model ◽  
Reaction Diffusion Model ◽  
Biological Pattern Formation ◽  
Spatio Temporal

This paper explores a two-species non-homogeneous reaction-diffusion model for the study of pattern formation with the Brusselator model. We scrutinize the pattern formation with initial conditions and Neumann boundary conditions in a spatially heterogeneous environment. In the whole investigation, we assume the case for random diffusion strategy. The dynamics of model behaviors show that the nature of pattern formation with varying parameters and initial conditions thoroughly. The model also studies in the absence of diffusion terms. The theoretical and numerical observations explain pattern formation using the reaction-diffusion model in both one and two dimensions.

Notizen: Comparison Between a Generic Reaction- Diffusion Model and a Synergetic Semiconductor System

1987 ◽  
Vol 42 (6) ◽  
pp. 655-656
Author(s):  
J. Parisi ◽  
J. Peinke ◽  
B. Röhricht ◽  
U. Rau ◽  
M. Klein ◽  
...  
Keyword(s):  
Symmetry Breaking ◽  
Diffusion Model ◽  
Physical Interpretation ◽  
Reaction Diffusion ◽  
Dynamical Model ◽  
Nonlinear Transport ◽  
Reaction Diffusion Model ◽  
Semiconductor System ◽  
Spatio Temporal ◽  
Simple Dynamical Model

This paper gives a concrete physical interpretation of a simple dynamical model based on the universal Rashevsky- Turing theory of symmetry-breaking morphogenesis in terms of spatio-temporal nonlinear transport phenomena in a synergetic semiconductor system.

scholarly journals Emerging strains of watermelon mosaic virus in Southeastern France: model-based estimation of the dates and places of introduction

2020 ◽  
Author(s):  
L Roques ◽  
C Desbiez ◽  
K Berthier ◽  
S Soubeyrand ◽  
E Walker ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Genetic Variants ◽  
Reaction Diffusion ◽  
Watermelon Mosaic Virus ◽  
Abiotic Conditions ◽  
Resident Population ◽  
Multiple Introductions ◽  
Modelling Framework ◽  
Reaction Diffusion Model ◽  
Spatio Temporal

ABSTRACTWhere and when alien organisms are successfully introduced are central questions to elucidate biotic and abiotic conditions favorable to the introduction, establishment and spread of invasive species. We propose a modelling framework to analyze multiple introductions by several invasive genotypes or genetic variants, in competition with a resident population, when observations provide knowledge on the relative proportions of each variant at some dates and places. This framework is based on a mechanistic-statistical model coupling a reaction-diffusion model with a probabilistic observation model. We apply it to a spatio-temporal dataset reporting the relative proportions of five genetic variants of watermelon mosaic virus (WMV, genus Potyvirus, family Potyviridae) in infections of commercial cucurbit fields. Despite the parsimonious nature of the model, it succeeds in fitting the data well and provides an estimation of the dates and places of successful introduction of each emerging variant as well as a reconstruction of the dynamics of each variant since its introduction.

scholarly journals Is the Skin an Excitable Medium? Pattern Formation in Erythema Gyratum Repens

2005 ◽  
Vol 6 (1) ◽  
pp. 57-65 ◽  
Author(s):  
Stephen Gilmore ◽  
Kerry A. Landman
Keyword(s):  
Pattern Formation ◽  
Reaction Diffusion ◽  
Biochemical Basis ◽  
Bz Reaction ◽  
Chemical Systems ◽  
Inflammatory Dermatosis ◽  
Reaction Diffusion Model ◽  
Oscillatory Chemical ◽  
Spatio Temporal ◽  
Scaly Skin

Erythema gyratum repens (EGR) is a rare, inflammatory dermatosis of unknown aetiology. The morphology of the eruption is striking and displays rapidly evolving circinate and gyrate bands of erythematous and scaly skin. Although the aetiology of the pattern is unknown, it has previously been noted that the eruption shares morphologic features with the patterns of spatio-temporal chemical concentration profiles observed in the Belusov-Zhabotinski (BZ) reaction. Yet this morphologic correspondence has not been investigated further. Here we apply a simple non-linear reaction–diffusion model, previously used to describe the BZ reaction, as a template for pattern formation in EGR, and show how the mechanism may provide a biochemical basis for many of the dynamic and morphologic features of the rash. These results are supported by the results of a cellular automaton simulation approximating the dynamics of oscillatory chemical systems—the Hodgepodge machine—where the spatio-temporal patterns developed show astonishing similarities to the morphology of EGR.

A REACTION–DIFFUSION MODEL FOR THE CONTROL OF CHOLERA EPIDEMIC

2016 ◽  
Vol 24 (04) ◽  
pp. 431-456 ◽  
Author(s):  
A. K. MISRA ◽  
ALOK GUPTA
Keyword(s):  
Temporal Dynamics ◽  
Temporal Distribution ◽  
Reaction Diffusion ◽  
Effective Control ◽  
Lytic Bacteriophage ◽  
Cholera Epidemic ◽  
Reaction Diffusion Model ◽  
Spatially Extended ◽  
Control Procedures ◽  
Spatio Temporal

Understanding the spatio-temporal dynamics of cholera outbreaks may help in devising more effective control procedures. In this paper, we have considered a reaction–diffusion system for biological control of cholera epidemic. Firstly, we have focused on temporal evolution of cholera in a region and its control using lytic bacteriophage in the aquatic reservoirs. Then, we have explored the effect of spatial dispersion of populations on the disease dynamics. We have observed the onset of sustained oscillations via Hopf-bifurcation for the endemic state of temporal system. This onset of fluctuations in populations depends upon the phage adsorption rate. But in the spatially extended setting, all the populations stabilize i.e., the spatio-temporal distribution of all the populations becomes uniform. Some numerical computations have been done to verify analytical results.

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