Multiple cycles of magnetic activity in the Sun and Sun-like stars and their evolution

The wavelet transform method for high-quality time-frequency analysis is applied to sets of observations of relative sunspot numbers and stellar chromosphere fluxes of 10 Sun-like stars.Wavelet analysis of solar data shows that in a certain interval of time there are several cycles of activity with periods of duration which vary considerably from each other:from quasi-biennial cycles to 100-yr cycles.Cyclic activity was detected in almost all Sun-like stars that we examined,even those that previously were not considered as stars with cyclic activity according to analysis using a Scargle periodogram.The durations of solar and stellar cycles significantly change during the observation period.     

Hydrometeorological conditions of the Volga region and current climate changes

The maps are presented of seasonal air temperature and precipitation amount anomalies averaged for the whole Volga region and adjacent territory for two time periods, 1946–1977 and 1978–2008. It is demonstrated that the considerable differences in the thermal and moistening regimes of the Volga region exist for these two periods. The relation is described between the variations of temperature and precipitation amount and the circulation types according to Vangengeim-Girs classification as well as the possibility to use these data for specifying the climatic scenarios obtained on the basis of physically complete hydrodynamic models.     

Gravitational Field of Fractal Distribution of Particles

In this paper we consider the gravitational field of fractal distribution of particles. To describe fractal distribution, we use the fractional integrals. The fractional integrals are considered as approximations of integrals on fractals. Using the fractional generalization of the Gauss’s law, we consider the simple examples of the fields of homogeneous fractal distribution. The examples of gravitational moments for fractal distribution are considered.     

The AD 1717 rock avalanche deposits in the upper Ferret Valley (Italy): a dating approach with cosmogenic 10Be

On 12 September AD 1717, a rock volume larger than 10 million m³ collapsed onto the Triolet Glacier, mobilized a mass composed of ice and sediment and travelled more than 7 km downvalley in the upper Ferret Valley, Mont Blanc Massif (Italy). This rock avalanche destroyed two small settlements, causing seven casualties and loss of livestock. No detailed maps were made at the time. Later investigators attributed accumulations of granitic boulders and irregular ridges on the upper valley floor to either glacial deposition, or the AD 1717 rock avalanche, or a complex mixture of glacial deposition, earlier rock avalanche and AD 1717 rock avalanche origin. In this study, we present cosmogenic ¹⁰Be exposure ages from nine boulders in the extensive chaotic boulder deposit with irregular ridges, two from Holocene glacier‐free areas, and one from a Little Ice Age moraine. Exposure ages between 330 ± 23 and 483 ± 123 a from eight of nine boulders from the chaotic deposit indicate that at least seven were deposited by the AD 1717 rock avalanche. The other three boulders yielded ¹⁰Be exposure ages of 10 900 ± 400, 9700 ± 400 and 244 ± 97 a, respectively. Our results are in good agreement with the existing chronology from dendrochronology and lichenometry, and radiocarbon analysis of wood samples, but not with older ¹⁴C ages from a peat bog in the upper part of the valley. Based on the new age control, the rock avalanche deposits cover the whole bottom of the upper Ferret valley. Copyright © 2012 John Wiley & Sons, Ltd.     

Late Jurassic ammonite evolution and paleoenvironment of the Russian Platform

The stratigraphic record shows a considerable decrease in ammonoid taxonomic diversity and distinct changes of ammonite shell morphology toward end of the Jurassic in the Central Russian Basin. By the end-Volgian, ammonites were represented by only two genera, belonging to a single family Craspeditidae, which differ markedly from previous ammonite families in their shell form. The end-Jurassic decrease in ammonoid biodiversity started in the mid-Volgian and is mainly correlated with shallowing of the shelf.