Observations and interpretation of solar decametric absorption bursts

The observations of intensity reductions or absorption bursts in the solar decametric radio-continuum are reported. The reductions are interpreted as the absorption of continuum radiation by a shock-generated ion-sound turbulence present in the layer above the continuum level. The duration of the absorption is attributed to the lifetime of the ion-sound turbulence while the depth of absorption is determined by the level of Langmuir waves generated as a result of absorption.     

Fatty-acid methyl esters dissolved in seawater and associated with suspended particulate material

Methyl esters of saturated and unsaturated fatty acids were isolated as trace components from organic material suspended in seawater. Methyl palmitate and methyl stearate were accumulated from the filtrate by adsorption onto Amberlite XAD-2 resin. Identification of most methyl esters is based on the comparison of gas chromatographic retention indices and mass spectrometric fragmentation with those of authentic standard compounds. In cases where reference substances were not available, identification is based on mass spectrometric and gas chromatographic properties of the unknown compounds.     

Orbital characteristics of dynamical models of elliptical galaxies

We use three different dynamical models for describing the motion in the meridian plane of an elliptical galaxy. Orbital characteristics of two polynomial models are compared with those given by a logarithmic potential for a fixed axial ratio of the equipotential surfaces, We also study the effects of an asymmetric perturbation caused by a companion galaxy on the orbital behaviour of the above models. Finally we present some theoretical arguments in order to support the numerical results.     

Negative absorption near a magnetized black hole: Black hole masers

The mechanism of the energy extraction from charged particles moving in the vicinity of black holes due to the negative absorption of electromagnetic waves is considered. It is shown that there exist a number of resonant frequencies for which the ring of particles circling in the equatorial plane of Kerr black holes amplifies the incident electromagnetic waves. The negative absorption coefficients are calculated both for non-relativistic and ultrarelativistic cases.     

Ergebnisse bisheriger Abklärungen über die systematische Beziehung zwischen Sommeralbeli und Winteralbeli (Coregonus lavaretus (L.)) im Walensee

A whitefish population considered to consist of two morphologically similar subpopulations is analyzed. Since a reproductive barrier existing earlier between the two subpopulations has lost its effectiveness, only one population exists today, having a very long reproductive period.      

Two new methods for solving large scale least squares in geodetic surveying computations

This paper considers the solution of linear least squares problems arising in space geodesy, with a special application to multi-station adjustment by a short arc method based on Doppler observations. We recall briefly the widely used second-order regression algorithm due to Brown for reducing the normal equations system. Then we propose two algorithms which avoid the use of the normal equations. The first one is a direct method that applies orthogonal transformations to the observation matrix directly, in order to reduce it to upper triangular form. The solution is then obtained by backsubstitution. The second method is iterative and uses a preconditioned conjugate gradient technique. A comparison of the three procedures is provided on data of the second European Doppler Observation Campaign (EDOC-2).