Iterative data-based controller tuning consists of iterative adjustment of the controller parameters towards the parameter values which minimise an {H2} performance criterion. The convergence to the global minimum of the performance criterion depends on the initial controller parameters and on the step size of each iteration. This article presents convergence properties of iterative algorithms when they are affected by disturbances.

This article demonstrates the generation of enhanced ion-acoustic waves by beam-plasma instability in a density cavity. The self-consistent equations of weak turbulence theory that include quasi-linear, decay, and scattering processes as well as convective and dispersive effects are numerically solved for a one-dimensional density cavity. It is shown that significant enhancements of ion-acoustic waves occur in the presence of counterstreaming electron beams and that the enhanced ion-acoustic waves are initially localized near the center of the density cavity at large wavelengths. Later in the evolution, the enhancement in the spectrum of ion-acoustic waves spreads out toward the edges of the cavity, with a shift to smaller wavelengths, while the enhancement near the center of the cavity tends to decrease in magnitude. The significance of the present findings is discussed.

This cross-sectional study evaluated the consumption of fluoridated dentifrice and associated factors in Passo Fundo, Rio Grande do Sul State, Brazil. A total of 688 households were selected. A structured questionnaire was answered by the mother to obtain demographics, habits, and toothpaste consumption. Household toothpaste consumption was considered low when a tube lasted > 1 month and high when < 1 month. Logistic regression models were applied to evaluate the association between consumption and independent variables. 61.2% of households showed high toothpaste consumption. In the multivariate model, mother's age > 50 years (OR = 1.62; 95%CI: 1.02-2.61), mother's brushing frequency (OR = 2.53; 95%CI: 1.53-4.16), number of people brushing (OR = 5.69; 95%CI: 3.68-8.81), and cosmetic features in choice of the dentifrice (OR = 1.64; 95%CI: 1.03-2.61) showed the highest odds of high toothpaste consumption.

The problem of electron-beam propagation in inhomogeneous solar wind is intimately related to the solar type II and/or type III radio bursts. Many scientists have addressed this issue in the past by means of quasi-linear theory, but in order to fully characterize the nonlinear dynamics, one must employ weak-turbulence theory. Available numerical solutions of the weak-turbulence theory either rely on only one nonlinear process (either decay or scattering), or when both nonlinear terms are included, the inhomogeneity effect is generally ignored. The present paper reports the full solution of weak-turbulence theory that includes both decay and scattering processes, and also incorporating the effects of density gradient. It is found that the quasi-linear effect sufficiently accounts for the primary Langmuir waves, but to properly characterize the back-scattered Langmuir wave, which is important for eventual radiation generation, it is found that both nonlinear decay and scattering processes make comparable contributions. Such a finding may be important in the quantitative analysis of the plasma emission process with application to solar type II and/or type III radio bursts.