Waves and Instabilities in Magnetized Dusty Plasmas

The status of waves and instabilities in magnetized dusty plasmas is summarized. The effects of an external magnetic field on low-frequency electrostatic and electromagnetic waves in dusty plasmas are discussed. The kinetic and hydrodynamic instabilities are shown to excite magnetized dusty plasma waves. The presence of the latter can give rise to an oscillatory wake-potential which can be responsible for the charged dust grain attraction. The relevance of our investigation to laboratory and space plasmas has been pointed out. This revised version was published online in July 2006 with corrections to the Cover Date.     

Nonlinear Drift-Alfvén Waves in Relativistically Hot Nonuniform Electron-Positron Plasmas

The magnetic viscosity tensor is derived for a magnetized relativistic collisionless plasma with temperature gradients. By means of this tensor we deduce the nonlinear equations for drift–Alfvén waves in a relativistic electron-positron low plasma with density and temperature gradients. It is shown that our new equations have solutions in the form of dipolar vortices. The present results should be relevant to a number of astrophysical objects with strong electron-positron pair production, e.g. in pulsars as well as in accretion disks and jets.     

Comments on the parametric excitation of low-frequency electrostatic waves

The nonlinear excitation of low-frequency electrostatic waves by a high-power pump wave is re-examined. In that way, we present simple formulas that are relevant for ionospheric heating experiments.     

Survivality and Impaired Growth in Arsenic Treated Fingerlings of Channa punctatus,a Fresh Water Murrel

The LC₅₀-values of As³⁺-compounds for Channa punctatus are determined for a 48-h exposure to 19.4 (18.02… 21.3) mg/1 and for a 96-h exposure to 14.3 (13.06… 16.80) mg/1. At a long-time exposure to 7.0 mg/1 As³⁺, during the first seven days there does not occur any change of growth, then the growth in length and the increase in weight decreased by 6.6 and 11.7%, respectively, till the 31st day. At the same time, the RNA content of the muscle decreased by 11.5% to 966.7 μg/g fresh weight and the protein content decreased by 12.5 % to 95.39 mg/g fresh weight.     

Deleterious effects of Malathion on survivality and growth of the fingerlings of Channa punctatus (BLOCH.), a freshwater murrel

The LC₅₀ of Malathion for Channu punctatus is determined for 24… 96 h of exposure as 10.95… 3.22 mg/l. At exposure to 2.5 mg./l Malathion, growth–measured by increase in weight–is significantly reduced from the 19th day and reduced by 10 % till the 31st day. During the same period of time, the RNA and protein contents of the muscle is lowered by 10 and 15 %, respectively, as compared with the control. In addition to an acute toxic effect, in sublethal concentrations Malathion has also pronounced effects on growth and metabolism.     

An evaluation of the CIC model of210Pb dating of sediments

Both linear and polynomial regression analysis techniques are used to assess the CIC (constant initial concentration) model of²¹⁰Pb dating. Results obtained using published²¹⁰Pb and porosity profiles in 12 freshwater sediment cores show that linear regression affords more reliable results. The polynomial regression, while capable of predicting the values of the constant or derived from porosity data, gives reasonable results only when all the coefficients of the polynomial are of appropriate sign. Lower values for all the parameters are obtained in all cases if the effect of compaction is not considered.     

On the stability and evolution of stationary whistler turbulence

It is shown that stationary turbulence consisting of an ensemble of small amplitude whistler wave packets becomes unstable against adiabatic perturbations. The rate of increase of the purely growing instability is presented. A stationary non-linear BGK solution for the whistler electric fields is obtained.