Search results for " Pd"
showing 10 items of 651 documents
Long time behavior for a dissipative shallow water model
2013
We consider the two-dimensional shallow water model derived by Levermore and Sammartino (Nonlinearity 14,2001), describing the motion of an incompressible fluid, confined in a shallow basin, with varying bottom topography. We construct the approximate inertial manifolds for the associated dynamical system and estimate its order. Finally, considering the whole domain R^2 and under suitable conditions on the time dependent forcing term, we prove the L^2 asymptotic decay of the weak solutions.
The Regularized Hadamard Expansion
2017
A local expansion is proposed for two-point distributions involving an ultraviolet regularization in a four-dimensional globally hyperbolic space-time. The regularization is described by an infinite number of functions which can be computed iteratively by solving transport equations along null geodesics. We show that the Cauchy evolution preserves the regularized Hadamard structure. The resulting regularized Hadamard expansion gives detailed and explicit information on the global dynamics of the regularization effects.
Information asymmetry in the agri-food sector and territorial marks: The case of the olive oil Val di Mazara PDO
2022
This article analyzes the importance of information in the agri-food market, since the presence of information asymmetry favors market failure. This analysis ex-amines the information asymmetry in the agri-food market and its geographical brands, PDO and PGI, focusing on the Sicilian oil sector of the olive oil Val di Mazara PDO. A quality product has specific organoleptic characteristics that give it flavors, fragrances and various nutritional properties. To protect this, there are the brands that are essential to avoid that between sellers and consumers there is information asymmetry and consequently the failure of the market. In fact, through this analysis are examined the evolution of t…
A SIMPLE PARTICLE MODEL FOR A SYSTEM OF COUPLED EQUATIONS WITH ABSORBING COLLISION TERM
2011
We study a particle model for a simple system of partial differential equations describing, in dimension $d\geq 2$, a two component mixture where light particles move in a medium of absorbing, fixed obstacles; the system consists in a transport and a reaction equation coupled through pure absorption collision terms. We consider a particle system where the obstacles, of radius $\var$, become inactive at a rate related to the number of light particles travelling in their range of influence at a given time and the light particles are instantaneously absorbed at the first time they meet the physical boundary of an obstacle; elements belonging to the same species do not interact among themselves…
Partial data inverse problems for Maxwell equations via Carleman estimates
2015
In this article we consider an inverse boundary value problem for the time-harmonic Maxwell equations. We show that the electromagnetic material parameters are determined by boundary measurements where part of the boundary data is measured on a possibly very small set. This is an extension of earlier scalar results of Bukhgeim-Uhlmann and Kenig-Sj\"ostrand-Uhlmann to the Maxwell system. The main contribution is to show that the Carleman estimate approach to scalar partial data inverse problems introduced in those works can be carried over to the Maxwell system.
On the semiclassical limit of the defocusing Davey-Stewartson II equation
2018
Inverse scattering is the most powerful tool in theory of integrable systems. Starting in the late sixties resounding great progress was made in (1+1) dimensional problems with many break-through results as on soliton interactions. Naturally the attention in recent years turns towards higher dimensional problems as the Davey-Stewartson equations, an integrable generalisation of the (1+1)-dimensionalcubic nonlinear Schrödinger equation. The defocusing Davey-Stewartson II equation, in its semi-classical limit has been shown in numerical experiments to exhibit behavior that qualitatively resembles that of its one-dimensional reduction, namely the generation of a dispersive shock wave: smooth i…
On the convergence of fixed point iterations for the moving geometry in a fluid-structure interaction problem
2019
In this paper a fluid-structure interaction problem for the incompressible Newtonian fluid is studied. We prove the convergence of an iterative process with respect to the computational domain geometry. In our previous works on numerical approximation of similar problems we refer this approach as the global iterative method. This iterative approach can be understood as a linearization of the so-called geometric nonlinearity of the underlying model. The proof of the convergence is based on the Banach fixed point argument, where the contractivity of the corresponding mapping is shown due to the continuous dependence of the weak solution on the given domain deformation. This estimate is obtain…
Response spectrum analysis of frame structures: reliability-based comparison between complete quadratic combination and damping-adjusted combination
2019
In the framework of seismic design of structures, response spectrum analysis (RSA) is the most commonly used approach in practice. The most popular combination rule is the complete quadratic combination (CQC) which is also prescribed by the most of seismic design codes and is based on the assumptions that the seismic acceleration is a white noise process and the peak factor ratios associated to the total and modal responses are unitary. Recently, the damping adjusted combination (DAC) rule has been developed for base-isolated structures to overcome the aforementioned simplified assumptions. Although it has been proved that the simplifications about peak factors lead to noticeable errors in …
An extended Darboux transformation to get families of solutions to the KPI equation
2023
By means of a Darboux transform with particular generating function solutions to the Kadomtsev-Petviashvili equation (KPI) are constructed. We give a method that provides different types of solutions in terms of particular determinants of order N. For any order, these solutions depend of the degree of summation and the degree of derivation of the generating functions. We study the patterns of their modulus in the plane (x, y) and their evolution according time and parameters.
Heat-stable antigen is expressed by murine keratinocytes and delivers costimulatory signals in T-cell activation.
1995
Heat-stable antigen (HSA), expressed by various antigen-presenting cells (APC), has been described as a costimulatory molecule for CD4+ T cells. Recently, we observed that HSA also serves as an important costimulatory molecule on epidermal Langerhans cells (LC). During these studies, low levels of HSA staining were also detected on normal murine keratinocytes (KC). To investigate whether HSA also is involved in T-cell activation by KC, normal murine KC or the spontaneously transformed KC cell-line PAM 212 were treated with PDB or PMA to induce HSA-expression. FACS analyses showed induction of HSA expression on normal murine KC, as well as PAM 212 cells. In functional assays PDB or PMA-treat…