In this paper, we generalize the so-called “nudging” algorithm in order to identify the initial condition of a dynamical system from experimental observations. The standard nudging algorithm consists in adding to the state equations of a dynamical system a feedback term, which is proportional to the difference between the observation and its equivalent quantity computed by the resolution of the...

In this paper, we present an additive Neumann-Neumann type parallel method for solving the system of algebraic equations arising from the mortar finite element discretization of a plate problem on a nonconforming mesh. Locally, we use a conforming Hsieh-CloughTocher macro element in the subdomains. The proposed method is almost optimal i.e. the condition number of the preconditioned problem gro...

A passive orthonomic system of PDEs defines a submanifold in the corresponding jet manifold, coordinated by so called parametric derivatives. We restrict the total differential operators and the prolongation of an evolutionary vector field v to this submanifold. We show that the vanishing of their commutators is equivalent to v being a generalized symmetry of the system. 1 Concerning the status...

has no solution if Ω ⊂ R , N ≥ 3, is bounded and starshaped with respect to some point, and 2∗ = 2N/(N − 2). In (P0) the nonlinear term is a power of u with the critical exponent (N + 2)/(N − 2). This terminology comes from the fact that the continuous Sobolev imbeddings H 0 (Ω) ⊂ L(Ω), for p ≤ 2∗ and Ω bounded, are also compact except when p = 2∗. This loss of compactness reflects in that the ...

Rats immunized with a semipurified preparation of the Escherichia coli heat-stable (ST) enterotoxin conjugated with a protein carrier were protected against challenge with semipurified or purified ST and viable organisms of multiple heterologous serotypes that produce only ST (LT-/ST+), but they were not protected against heal-labile (LT) toxin or viable strains which produce LT either alone (L...

Nonlinear growth of one-dimensional density structures with a frozen-in magnetic field is investigated in Newtonian cosmology. A mechanism of magnetic field amplification is discussed. We discuss the relation between the initial conditions for the velocity field and the basic time-scales determining the growth of the magnetized structure.

Serum pepsinogen I and II levels have recently become popular as indicators of atrophic gastritis in epidemiological studies. Previous studies show a significant association between serum pepsinogen levels and endoscopically diagnosed atrophic gastritis. This study assesses the level of agreement between the degree of atrophic gastritis as assessed by endoscopic examination and by serum pepsino...

A recurrent theme in the description of phase portraits of dynamical systems is that of elliptic islands in a chaotic sea. Usually this picture is invoked in the context of smooth twist maps of the annulus or the torus, like the standard map. In this setting ‘elliptic islands’ refers to the topological disks bounded by periodic smooth curves surrounding elliptic periodic points. Establishing th...

1. In the beginning In the beginning, there was the DN (Deductive Nomological) model of explanation, articulated by Hempel and Oppenheim (1948). According to DN, scientific explanation is subsumption under natural law. Individual events are explained by deducing them from laws together with initial conditions (or boundary conditions), and laws are explained by deriving them from other more fund...

Sufficient number of linear and noisy measurements for exact and approximate sparsity pattern/support set recovery in the high dimensional setting is derived. Although this problem as been addressed in the recent literature, there is still considerable gaps between those results and the exact limits of the perfect support set recovery. To reduce this gap, in this paper, the sufficient con...