Water Dynamics and Structure in the Estuary of the Partizanskaya River (Nakhodka Bay,Sea of Japan)

Water Resources - Field studies of the seasonal and daily dynamics of the mixing zone were carried out in the microtidal estuary of the Partizanskaya River. The position of the mixing zone was...     

The Effect of Splitting of Raw Data into Training and Test Subsets on the Accuracy of Predicting Spatial Distribution by a Multilayer Perceptron

Mathematical Geosciences - The paper discusses the influence of various methods for splitting raw data into test and training subsets on the accuracy of the prediction of the spatial distribution...     

Study of nonlinear currents induced by coincident surface waves in liquid

This is an experimental study of the mixing induced by coincident surface waves in a liquid. The main mechanism leading to the emergence of mixing was shown to be the middle currents generated by coincident waves. The regime of these currents strongly depends on the amplitude of surface waves. For waves of near-critical amplitudes, an intense turbulization of middle currents is observed. Patterns of the velocity field were obtained using the Particle Imaging Velocimetry (PIV) technique for different amplitudes of surface waves. The results obtained can be used to estimate mixing in the near-surface oceanic layer.     

A new generation of Pulkovo observatory meridian instruments and the first results of observations

The results of investigations and observations with classical meridian circle MK-200 and photographic vertical circle (PVC) after its modernization and automation are discussed. The data concerning the stability of the instrumental system and the flexure of the Pulkovo Horizontal meridian circle (HMC) are given. New work on the establishment of in axial meridian circle in Nikolaev, Ecker meridian circle and reflecting one in Pulkovo is mentioned.     

Precambrian crustal contribution to the Variscan accretionary prism of the Kaczawa Mountains (Sudetes,SW Poland): evidence from SHRIMP dating of detrital zircons

SHRIMP dating of detrital zircons from sandstones of the Gackowa Formation (Kaczawa Complex, Sudetes, SW Poland) indicates input from late (550–750 Ma) and early Proterozoic to Archaean sources (∼2.0–3.4 Ga, the latter being the oldest recorded age from the Sudetic region). These dates preclude within-terrane derivation from seemingly correlatory acid volcanic rocks of early Palaeozoic age. Rather, they indicate provenance from Cadomian and older rocks that currently form part of other, geographically distant terranes; the most likely source identified to date is the Lusatian Block in the Saxothuringian Zone. Hence, the Gackowa Formation may be late Proterozoic rather than early Palaeozoic in depositional age, possibly coeval with the late Proterozoic (pre-Cadomian) greywackes of Lusatia, being subsequently tectonically interleaved with early Palaeozoic volcanic rocks into the Kaczawa accretionary prism during the Variscan orogeny. However, correlation with the lithologically similar early Ordovician Dubrau Quartzite of Saxothuringia, and so assignation to the early Paleozoic (post-Cadomian) rift succession deposited at the northern margin of Gondwana, cannot yet be precluded.     

On the nature of the unique eclipsing system H 187 (HMW 15)

We present our photometric observations of the T Tauri star H 187. They confirm our conclusion that a new extended eclipse has begun in this young object. By the end of 2005, H 187 reached its minimum light following which its brightness began to slowly increase. Comparison with the previous ～3.5-yr-long eclipse observed by Cohen et al. shows that the new eclipse follows the previous eclipse fairly closely and, hence, it was caused by a second passage of the same extended dust or gas-dust cloud around the object. We have estimated the period between these events to be 4.7 yr. The object reddened during the eclipse, suggesting that the extinction was produced by small grains ～0.1μm in size. Possible mechanisms of such unusual eclipses are discussed. We draw an analogy between these eclipses and the cycles of photometric activity observed in UX Ori stars. Light curves similar to those observed for H 187 are shown to be obtained in the model of a young binary system with a low-mass companion accreting matter from the remnants of a protostellar cloud at a rate of ～10^?9 M _⊙ yr^?1.