Markov Properties of Electrical Discharge Current Fluctuations in Plasma

Using the Markovian method, we study the stochastic nature of electrical discharge current fluctuations in the Helium plasma. Sinusoidal trends are extracted from the data set by the Fourier-Detrended Fluctuation analysis and consequently cleaned data is retrieved. We determine the Markov time scale of the detrended data set by using likelihood analysis. We also estimate the Kramers-Moyal's coefficients of the discharge current fluctuations and derive the corresponding Fokker-Planck equation. In addition, the obtained Langevin equation enables us to reconstruct discharge time series with similar statistical properties compared with the observed in the experiment. We also provide an exact decomposition of temporal correlation function by using Kramers-Moyal's coefficients. We show that for the stationary time series, the two point temporal correlation function has an exponential decaying behavior with a characteristic correlation time scale. Our results confirm that, there is no definite relation between correlation and Markov time scales. However both of them behave as monotonic increasing function of discharge current intensity. Finally to complete our analysis, the multifractal behavior of reconstructed time series using its Keramers-Moyal's coefficients and original data set are investigated. Extended self similarity analysis demonstrates that fluctuations in our experimental setup deviates from Kolmogorov (K41) theory for fully developed turbulence regime.Comment: 25 pages, 9 figures and 4 tables. V3: Added comments, references, figures and major correction

Information and digital literacies; a review of concepts

A detailed literature reviewing, analysing the multiple and confusing concepts around the ideas of information literacy and digital literacy at the start of the millennium. The article was well-received, and is my most highly-cited work, with over 1100 citations

Nonlinear evolution of drift instabilities

The nonlinear evolution of collisionless drift instabilities in a shear-free magnetic field has been studied by means of gyrokinetic particle simulation as well as numerical integration of model mode-coupling equations. The purpose of the investigation is to identify relevant nonlinear mechanisms responsible for the steady-state drift wave fluctuations. It is found that the saturation of the instability is mainly caused by the nonlinear E x B convection of the resonant electrons and their associated velocity space nonlinearity. The latter also induces energy exchange between the competing modes, which, in turn, gives rise to enhanced diffusion. The nonlinear E x B convection of the ions, which contributes to the nonlinear frequency shift, is also an important ingredient for the saturation

Propagation of ion beams through a tenuous magnetized plasma

When an ion beam is propagated through a plasma, the question of charge neutralization is critical to its propagation. We consider such a problem where the plasma is magnetized with magnetic field perpendicular to the beam. The plasma-number density and beam-number density are assumed comparable. We reduce the problem to a two-dimensional model, which we solve. The solution suggests that it should be possible to attain charge neutralization if the beam density is properly varied along itself

Voorlichting bij patiënten met atriumfibrillatie : een gecontroleerde effectstudie

In outpatient care settings, there is often a lack of possibilities to inform patients sufficiently about their diagnosed disease. This is partially due to inefficient time management and a shortage of financial means. The patient is left with many unanswered questions, which can lead to uncertainty about their disease and how to deal with it. In this study the effects of a short patient education program are examined using a pre-posttest control group design and a questionnaire, the effects of a multimedia mode of patient education for patients diagnosed with atrial fibrillation are assessed on well-being, knowlegde, disease acceptance, treatment compliance, uncertainty, physical complaints, anxiety and depression. The patient education program results in a significant stronger decrease of uncertainty within the education group than in the control group. Knowledge about the disease increases significantly more in the experimental group too, compared with the control group. There is no improvement noticeable for any of the other measured variables. All in all, the results are modest, but, considering the small investment needed for such an intervention, it can be considered a valuable additional instrument in cardiology care

Voorlichting bij patiënten met atriumfibrillatie: een gecontroleerde effectstudie

In outpatient care settings, there is often a lack of possibilities to inform patients sufficiently about their diagnosed disease. This is partially due to inefficient time management and a shortage of financial means. The patient is left with many unanswered questions, which can lead to uncertainty about their disease and how to deal with it. In this study the effects of a short patient education program are examined using a pre-posttest control group design and a questionnaire, the effects of a multimedia mode of patient education for patients diagnosed with atrial fibrillation are assessed on well-being, knowlegde, disease acceptance, treatment compliance, uncertainty, physical complaints, anxiety and depression. The patient education program results in a significant stronger decrease of uncertainty within the education group than in the control group. Knowledge about the disease increases significantly more in the experimental group too, compared with the control group. There is no improvement noticeable for any of the other measured variables. All in all, the results are modest, but, considering the small investment needed for such an intervention, it can be considered a valuable additional instrument in cardiology care

State of the Climate in 2012

International audienceEditors note: For easy download the posted pdf of the State of the Climate for 2012 is a very low-resolution file. A high-resolution copy of the report is available by clicking here. Please be patient as it may take a few minutes for the high-resolution file to download