Analysis of Oscillations and Defect Measures for the Quasineutral Limit in Plasma Physics

We perform a rigorous analysis of the quasineutral limit for a hydrodynamical model of a viscous plasma represented by the Navier Stokes Poisson system in $3-D$. We show that as $\lambda\to 0$ the velocity field $u^{\lambda}$ strongly converges towards an incompressible velocity vector field $u$ and the density fluctuation $\rho^{\lambda}-1$ weakly converges to zero. In general the limit velocity field cannot be expected to satisfy the incompressible Navier Stokes equation, indeed the presence of high frequency oscillations strongly affects the quadratic nonlinearities and we have to take care of self interacting wave packets. We shall provide a detailed mathematical description of the convergence process by using microlocal defect measures and by developing an explicit correctors analysis. Moreover we will be able to identify an explicit pseudo parabolic pde satisfied by the leading correctors terms. Our results include all the previous results in literature, in particular we show that the formal limit holds rigorously in the case of well prepared data.Comment: Submitted pape

On the vanishing electron-mass limit in plasma hydrodynamics in unbounded media

We consider the zero-electron-mass limit for the Navier-Stokes-Poisson system in unbounded spatial domains. Assuming smallness of the viscosity coefficient and ill-prepared initial data, we show that the asymptotic limit is represented by the incompressible Navier-Stokes system, with a Brinkman damping, in the case when viscosity is proportional to the electron-mass, and by the incompressible Euler system provided the viscosity is dominated by the electron mass. The proof is based on the RAGE theorem and dispersive estimates for acoustic waves, and on the concept of suitable weak solutions for the compressible Navier-Stokes system

Generating benchmarks by random stepwise refinement of Petri nets

The quality of algorithms is often determined by benchmarking, i.e., testing the algorithm on a predetermined data set. In contrast to traditional benchmarking, with fixed data set, we present a way to generate random sets of test data. In this paper we present random classes of Petri nets and a method to generate finite samples from such a class. The classes may contain infinitely many Petri nets, each net with its own probability to be generated. This generation method is based on stepwise application of construction rules such as refinement rules. Each random class of Petri nets has a probability distribution for each of its characteristics. We illustrate the approach by estimating this distribution for some simple characteristics

Value and Limitations of Electrocardiogram in Diagnosis of Slight and Subacute Coronary Attacks

The electrocardiogram recorded at the initial consultation was compared with the final diagnosis in 211 consecutive suspected slight or sub-acute coronary attacks in 206 patients

Análise comparativa da assembléia de aves em dois remanescentes florestais no interior do Estado de São Paulo, Brasil Comparative analysis of birds community in two forested fragments in the State of São Paulo, Brazil

Realizou-se o levantamento quantitativo e qualitativo da comunidade de aves de dois fragmentos de floresta estacional semidecídua no interior do estado de São Paulo de julho de 2004 a julho de 2005. Para o estudo quantitativo utilizou-se da metodologia de Pontos de Escuta. Foram analisados os índices de diversidade e de freqüência de ocorrência dessa comunidade. O levantamento qualitativo registrou 181 espécies na Fazenda Rio das Pedras - FRP (Itapetininga, 350 ha) e 126 espécies na Fazenda Santa Maria II - FSM (Buri, 480 ha), enquanto que o levantamento quantitativo registrou a presença de 73 espécies em 988 contatos e 64 espécies em 1019 contatos para FRP e FSM, respectivamente. O índice pontual de abundância (IPA) variou de 0,01 (1 contato) a 1,32 (132 contatos), para FRP e na FSM variou entre 0,01 (1 contato) a 0,97 (97 contatos). A diversidade do fragmento da FRP foi de H’ = 3,04 e na FSM de H’ = 2,85 onde a eqüitatividade em ambas áreas foi de 0,91. A comunidade de aves nos fragmentos estudados mostrou o mesmo padrão encontrado em outros fragmentos de floresta estacional semidecídua de tamanhos relativos. As categorias alimentares mais representativas nos dois remanescentes foram insetívoras (53% na FSM e 50% na FRP) e frugívoras (23% na FSM e 26% na FRP). Dentre os insetívoros, destacaram-se as famílias Tyrannidae na FSM e Thamnophilidae na FRP. Tanto na FSM como na FRP os insetívoros de sub-bosque foram mais representativos (53% e 51,4% respectivamente), seguidos pelos frugívoros de sub-bosque (50%) na FSM e frugívoros de copa (52,6%) na FRP. A importância do estudo de comunidade de aves esta ligada à elaboração do plano de manejo e conservação das áreas naturais.<br>Qualitative and quantitative survey of bird community were performed in two distinct semideciduous forest in the interior of the State of São Paulo from July 2004 to July 2005. Point Counts were used for the quantitative survey followed by diversity and frequence of ocurrence indexes of the bird assemblage. The qualitative survey registered a total of 181 species of birds at Fazenda Rio das Pedras (FRP, Itapetininga, 350 ha) and 126 at Fazenda Santa Maria II (FSM II, Buri, 260 ha). The qualitative survey registered 73 species in 998 contacts and 64 species en 1019 contacts, respectively, for FRP and FSM II. The ponctual index of abundance (IPA) varied from 0.01 (one contact) to 1.32 (132 contacts) at FRP and from 0.01 (one contact) to 0.97 (97 contacts) at FSM II. The general diversity index for FRP was H’ = 2.85 and H’ = 3.04 at FSM II. Both areas presented an evenness index of E = 0.91. The bird community in both patched of forest showed the same pattern found in other different forest fragments of relative size studies by many distinct authors. In both localities, insectivorus (53% at FSM e 50% at FRP) and frugivorus (23% na FSM e 26% na FRP) birds were the most representative. Among the former, Tyrannidae and Thamnophilidae were predominant, respectively, at FSM and FRP. In both places understory insectivorous birds were dominant (53% at FSM and 51,4% at FRP), followed by understory frugivorus at FSM (50%) and by canopy frugivorus (52,6%) at FRP. The importance of bird community in forest remmants in linked to managing and conservation of wild natural forested in Stade of São Paulo