Anomalous magnetic viscosity in accretion disks with q-distributed plasmas

Based on the equations of the self-generated magnetic field in the q-distributed plasmas, the studies show that the magnetic field is modulationally unstable by the perturbation method and the equations have self-similar collapse solution. The anomalous magnetic viscosity of accretion disks generates from highly spatially intermittent flux of the self-generated magnetic field. In addition, the anomalous viscosity coefficient is 8 orders more than the molecular viscosity and is modified by the adjustable index q, which may preferably explain the observations.     

Temporal Evolution and Petrogenesis of an Archaean Crustal Segment at Yellowknife, N.W.T., Canada

Geochronology of several Archaean rock units in the Slave Provinceestablishes a sequence of events which may be treated as a singletectonic cycle, approximately 75 m.y. in duration, leading tothe formation of a new crustal segment. The oldest rocks (2650m.y.) are basic metavolcanics with largely calc-alkaline characteristics.Metamorphic adjustment to greenschist facies conditions is largelyisochemical but departures from regular serial variation inalkalis are noted. Comparison with experimental studies suggeststhat the basalt-dacite volcanic association is probably theearly extrusive expression of the subcrustal processes whichled to the intrusion of calc-alkaline batholiths into the deformingvolcanic-sedimentary pile. Zircon U-Pb and whole rock Rb-Sr isochron ages of 2620–2640m.y. are recorded for the syn-kinematic quartz diorite batholithsand 2590–2610 m.y. for the major late-kinematic bodies.Pegmatitic adamellites (2575±25 m.y.) are the youngestplutonic units. Regional metamorphism of the andalusite-sillimanitefacies series reflects the relative unimportance of load pressurein the thin-crustal Kenoran deformation. Comparison of the resultsobtained by the three radiometric methods confirms that an intervalof over 100 m.y. may elapse between the time of emplacementof a given rock unit and the subsequent closure of the biotiteK-Ar system. The sequence of K-Ar mineral dates is in accordwith the relative argon retentivities of the various minerals.     

A trend in the gaps in redshift distribution of QSOs

Analysis of gaps in the emission line redshift distribution of 537 QSOs shows a single definite trend in the distribution of the gaps. The trend is similar for radio-quiet objects, radio sources and all QSO's taken together. However, the trend does not suggest any periodicity in redshifts in any of the three cases.     

Reflectance spectra for sodium and potassium doped ammonia frosts: Implications for Io's surface

This paper reports measurements of the reflection spectra of sodium and potassium doped ammonia frosts as a function of alkali metal concentration which cover the wavelength range 0.35–2.5 μm. The purpose of the measurements was to determine whether or not the reflection spectra for such a solid was compatible with the spectral albedo of Io. The data show that with a sufficiently large alkali metal concentration, the reflection spectra of the doped ammonia frost do not display the characteristic ammonia features at 2.0 and 2.25 μm. The high reflectance of the more concentrated samples and the character of the observed reflection spectrum make it difficult to rule out sodium doped ammonia frost as a surface constituent on Io on the basis of existing data.     

Multiple impacts in the Earth's cratering history

Post-bombardment periods of increased impact flux on Earth are probably due to the decay of captured Apollo object group orbits. The origin of the Messier binary impact structure on the Moon implies the breakup of a single impactor as the origin of a Cretaceous/Tertiary multiple impact.     

The ionization mechanism in low level emission galaxy nuclei: Shocks

We analyze the emission component of galaxy nuclei at very low intensity levels (W(H)2Å). This emission level is considerably lower than that of classical LINERS like NGC 1052. We have access to weaker emission lines by averaging spectra with similar line ratios for H [NII], and [SII]. From the resulting spectrum for very low level emission nuclei, the [SII] 6717, 6731/[SIII] 9069, 9532 line ratio criterion (Diazet al., 1985a) unambiguously shows that shock-wave heating is the mechanism responsible for the ionization in such objects.     

Similarity solution for the propagation of shock waves with varying energy in non-uniform medium

A model of self-similar propagation of shock waves driven by a flare energy release in a non-uniform atmosphere has been considered. The total energy content of the model is assumed to be increased with time within the inner expanding surface and shock front. Finally the variation of velocity, pressure, density, and energy of the model have been discussed. The gas is assumed to be grey and opaque.     

Radiometry of near-earth asteroids

We report 10 micrometers infrared photometry for 22 Aten, Apollo, and Amor asteroids. Thermal models are used to derive the corresponding radiometric albedos and diameters. Several of these asteroids appear to have surfaces of relatively high thermal inertia due to the exposure of bare rock or a coarse regolith. The Apollo asteroid 3103, 1982 BB, is recognized as class E. The Jupiter-crossing Amor asteroid 3552, 1983 SA, is confirmed as class D, but low albedos remain rare for near-Earth asteroids.     

On the periodical structures in populations of galaxies and of clusters of galaxies

Analysing the distribution of the redshift of clusters of galaxies, obtained from the catalogue of SCHMIDT (1986), two already known periodical structures were confirmed and both periods were extended by a number of periods — approximately by two times (We elucidated 5 new periods in the first structure and 4 in the second.). The statistical significance of these structures was estimated to 0.01 in the first case and to 0.02 in the second one. Particularly, the second structure may be the largest known object in the Universe (about 900 Mpc at H = 75 km s^-1 Mpc^-1). These results agree with the predictions of the axion-dominated early Universe. In addition, we discovered periodical structures of an another type — in luminosity functions of galaxies, which are members of rich clusters. Bei der Analyse des Katalogs von SCHMIDT (1986) wurden zwei periodische Strukturen in den Verteilungen der Rotverschiebungen von Galaxienhaufen festgestellt. In den beiden Strukturen wurden 5 bzw. 4 neue Perioden beobachtet, weshalb sich die Periodenzahl in jeder der beiden Strukturen etwa verdoppelt hat. Die statistische Signifikanzen dieser Strukturen wurden zu 0.01 und 0.02 abgeschätzt. Möglicherweise entspricht die zweite Struktur dem größten bekannten Objekt des Weltalls (etwa 900 Mpc bei H = 75 km s^-1 Mpc^-1). Diese Resultate stützen die Theorie eines axiondominierten frühen Universums. Außerdem wurden weitere periodische Strukturen in der Leuchtkraftfunktion von Galaxien aus reichen Galaxien-haufen entdeckt.