All a b c d e f g h i j k l m n o p q r s t u v w x y z Other

Previous Page 25 Next

Displaying 481 – 500 of 3302

Showing per page

Atherosclerosis Initiation Modeled as an Inflammatory Process

N. El Khatib, S. Génieys, V. Volpert (2010)

Mathematical Modelling of Natural Phenomena

In this work we study the inflammatory process resulting in the development of atherosclerosis. We develop a one- and two-dimensional models based on reaction-diffusion systems to describe the set up of a chronic inflammatory response in the intima of an artery vessel wall. The concentration of the oxidized low density lipoproteins (ox-LDL) in the intima is the critical parameter of the model. Low ox-LDL concentrations do not lead to a chronic inflammatory reaction. Intermediate ox-LDL concentrations...

Attractors for stochastic reaction-diffusion equation with additive homogeneous noise

Jakub Slavík (2021)

Czechoslovak Mathematical Journal

We study the asymptotic behaviour of solutions of a reaction-diffusion equation in the whole space ℝ d driven by a spatially homogeneous Wiener process with finite spectral measure. The existence of a random attractor is established for initial data in suitable weighted L 2 -space in any dimension, which complements the result from P. W. Bates, K. Lu, and B. Wang (2013). Asymptotic compactness is obtained using elements of the method of short trajectories.

Autowaves in the Model of Infiltrative Tumour Growth with Migration-Proliferation Dichotomy

A.V. Kolobov, V.V. Gubernov, A.A. Polezhaev (2011)

Mathematical Modelling of Natural Phenomena

A mathematical model of infiltrative tumour growth is investigated taking into account transitions between two possible states of malignant cells: proliferation and migration. These transitions are considered to depend on oxygen level in a threshold manner where high oxygen concentration allows cell proliferation, while concentration below a certain critical value induces cell migration. The infiltrative tumour spreading rate dependence on model parameters is obtained. It is shown that the tumour...

Axiomatique des fonctions biharmoniques. II

Emmanuel P. Smyrnelis (1976)

Annales de l'institut Fourier

Dans un espace biharmonique, on définit un balayage de couples de mesures et, en particulier, on retrouve les trois mesures du problème de Riquier. Une de ces mesures n’étant pas harmonique, son étude présente un certain intérêt. On établit, dans ce cadre, des inégalités de type Harnack et on introduit les fonctions hyperharmoniques d’ordre 2. Le problème de la construction d’un espace biharmonique à partir de deux espaces harmoniques est aussi étudié. Enfin, on donne des applications de la théorie...

B q for parabolic measures

Caroline Sweezy (1998)

Studia Mathematica

If Ω is a Lip(1,1/2) domain, μ a doubling measure on ∂ p Ω , ∂ / ∂ t - L i , i = 0,1, are two parabolic-type operators with coefficients bounded and measurable, 2 ≤ q < ∞, then the associated measures ω 0 , ω 1 have the property that ω 0 ∈ B q ( μ ) implies ω 1 is absolutely continuous with respect to ω 0 whenever a certain Carleson-type condition holds on the difference function of the coefficients of L 1 and L 0 . Also ω 0 ∈ B q ( μ ) implies ω 1 ∈ B q ( μ ) whenever both measures are center-doubling measures. This is B. Dahlberg’s result for elliptic measures extended...

Barenblatt solutions and asymptotic behaviour for a nonlinear fractional heat equation of porous medium type

Juan Luis Vázquez (2014)

Journal of the European Mathematical Society

We establish the existence, uniqueness and main properties of the fundamental solutions for the fractional porous medium equation introduced in [51]. They are self-similar functions of the form u ( x , t ) = t – α f ( | x | t – β ) with suitable and β . As a main application of this construction, we prove that the asymptotic behaviour of general solutions is represented by such special solutions. Very singular solutions are also constructed. Among other interesting qualitative properties of the equation we prove an Aleksandrov reflection...

Barriers for a class of geometric evolution problems

Giovanni Bellettini, Matteo Novaga (1997)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

We present some general results on minimal barriers in the sense of De Giorgi for geometric evolution problems. We also compare minimal barriers with viscosity solutions for fully nonlinear geometric problems of the form u t + F ⁢ t , x , ∇ ⁡ u , ∇ 2 ⁡ u = 0 . If F is not degenerate elliptic, it turns out that we obtain the same minimal barriers if we replace F with F + , which is defined as the smallest degenerate elliptic function above F .

Behaviour of global solutions for a system of reaction-diffusion equations from combustion theory

Salah Badraoui (1999)

Applicationes Mathematicae

We are concerned with the boundedness and large time behaviour of the solution for a system of reaction-diffusion equations modelling complex consecutive reactions on a bounded domain under homogeneous Neumann boundary conditions. Using the techniques of E. Conway, D. Hoff and J. Smoller [3] we also show that the bounded solution converges to a constant function as t → ∞. Finally, we investigate the rate of this convergence.

Currently displaying 481 – 500 of 3302