The present paper reports on the first two-dimensional (2D) self-consistent solution of weak turbulence equations describing the evolution of electron-beam-plasma interaction in which quasilinear as well as nonlinear three-wave decay processes are taken into account. It is found that the 2D Langmuir wave decay processes lead to the formation of a quasicircular ring spectrum in wave number space. It is also seen that the 2D ring-spectrum of Langmuir turbulence leads to a tendency to isotropic heating of the electrons. These findings contain some important ramifications. First, in the literature, isotropization of energetic electrons, detected in the solar wind for instance, is usually attributed to pitch-angle scattering. The present finding constitutes an alternative mechanism, whose efficiency for other parametric regimes has to be investigated. Second, when projected onto the one-dimensional (1D) space, the 2D ring spectrum may give a false impression of Langmuir waves inverse cascading to longer wavelength regime, when in reality, the wavelength of the turbulence does not change at all but only the wave propagation angle changes. Although the present analysis excludes the induced scattering, which is another process potentially responsible for the inverse cascade, the present finding at least calls for an investigation into the relative efficacy of the inverse-cascading process in 1D vs 2D.

Numerical solutions for equations of weak turbulence theory that describe the beam-plasma interaction are obtained in two dimensions (2D). The self-consistent theory governs quasilinear processes as well as nonlinear decay and scattering processes. It is found that the Langmuir turbulence scatters into a quasi-circular ring spectrum in 2D wave number space, accompanied by quasi-isotropic heating of the electrons. When projected onto the one-dimensional (1D) space, 2D Langmuir turbulence spectrum appears as an inverse cascade, when in reality, the wavelength of the turbulence does not change but only the wave propagation angle changes. These findings are similar to those obtained in a previous analysis in which scattering processes were not taken into account, but it is found that the scattering term leads to a quantifiably higher scattering rate.

AIM: To assess the effect of systemic azithromycin as a supplement to scaling and root planing (SRP) in the treatment of aggressive periodontitis (AgP). MATERIAL AND METHODS: Twenty-four individuals (13-26 years old) underwent a plaque control program, and then were treated with SRP. Subjects were assigned randomly into two groups; the test group used 500 mg azithromycin once a day for 3 days, whereas the control group used a placebo. Clinical variables were assessed at baseline, 3, 6, 9, and 12 months. The periodontal status at baseline and 12 months was compared using the Wald test, and adjusting for the effect of clustering of teeth within subjects. RESULTS: There were no significant differences in visible plaque, gingival bleeding, and supragingival calculus between groups throughout the study. Periodontal probing depth (PPD) and clinical attachment level improved significantly from baseline to 12 months in both groups, with the test group showing significantly more reduction in mean PPD compared with controls (2.88 mm versus 1.85 mm, respectively, p=0.025). Subjects administering azithromycin showed a higher percentage of teeth with attachment gain >or=1 mm (81.34 versus 63.63, p=0.037), whereas the controls had higher percentage of teeth with attachment loss >or=1 mm (11.57 versus 2.24, p=0.015). CONCLUSIONS: The adjunctive use of azithromycin has the potential to improve periodontal health of young patients with AgP.

Electron distributions with various degrees of asymmetry associated with the energetic tail population are commonly detected in the solar wind near 1 AU. By numerically solving one-dimensional electrostatic weak turbulence equations the present paper demonstrates that a wide variety of asymmetric energetic tail distributions may result. It is found that a wide variety of asymmetric tail formation becomes possible if one posits that the solar wind electrons are initially composed of thermal core plus field-aligned counterstreaming beams, instead of the customary thermal population plus a single beam. It is shown that the resulting nonlinear wave-wave and wave-particle interactions lead to asymmetric nonthermal tails. It is found that the delicate difference in the average beam speeds associated with the forward versus backward components is responsible for the generation of asymmetry in the energetic tail.

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O artigo apresenta uma concepção do fluxo de consciência a partir de um modelo de naturalização da consciência de base metafísica não-materialista, inspirado na filosofia de Espinosa. Procura-se responder à questão colocada por Arthur Prior, em seu artigo ?Thank Goodness That?s Over? (1959), acerca do caráter problemático do significado de um certo tipo de proposições indexadas temporalmente no quadro de teorias que recusam a realidade do tempo. Para tanto, defende-se a hipótese de que essas proposições são irredutíveis a proposições não temporalizadas, seu sentido sendo determinado pelo caráter adverbial dos indexadores temporais e pela função de expressar estados subjetivos referencialmente opacos (aproximados no texto ao conceito espinosista de afeto). Essa função, por sua vez, seria determinante para a constituição do mental enquanto tal e para a realidade do domínio prático.

The foundationalist needs to deal with two fundamental problems: (i) to explain how a justificator grants justification without itself need justification and (ii) to determine the justificator’s epistemic status. Burdzinski (Burdzinski 2007), following Sellars and Bonjour, argues that the perceptive experience could not be a response to the first problem, because if its content was not propositional it would not grant justification and if its content was propositional it would grant justification and would require justification. My proposal is that perceptual experience justifies in virtue of its representational nature. The act of taking the content of a perception by its face value is justified until there is a reason to the contrary, ie, this act is prima facie justified. This forces us to answer the second problem by saying that the basic justificator is not infallible. This falibilist response dislike the skeptic, but it is the best foundationalist answer to epistemic regress.