Variable binaries and variables in binaries in the Binary star DataBase

The Binary star DataBase(BDB, http://bdb.inasan.ru) combines data from catalogs of binary and multiple stars of all observational types. There is a number of ways for variable stars to form or to be a part of binary or multiple systems. We describe how such stars are represented in the database.     

The primordial baryonic clouds and their contribution to the cosmic microwave background anisotropy and polarization formation

We discuss possible distortions of the ionization history of the Universe in a model with small-scale baryonic clouds. The corresponding scales of the clouds are much smaller than the typical galactic mass-scales. These clouds are considered in a framework of the cosmological model with isocurvature and adiabatic perturbations. In this model the baryonic clouds do not influence the cosmic microwave background anisotropy formation directly as additional sources of perturbations, but they can change the kinetics of the hydrogen recombination . We also study the corresponding distortions of the anisotropy and polarization power spectra in connection with the launched MAP and future Planck missions.     

Relativistic gravitational potential and its relation to mass-energy

From the general theory of relativity a relation is deduced between the mass of a particle and the gravitational field at the position of the particle. For this purpose the fall of a particle of negligible mass in the gravitational field of a massive body is used. After establishing the relativistic potential and its relationship to the rest mass of the particle, we show, assuming conservation of mass-energy, that the difference between two potential-levels depends upon the value of the radial metric coefficient at the position of an observer. Further, it is proved that the relativistic potential is compatible with the general concept of the potential also from the standpoint of kinematics. In the third section it is shown that, although the mass-energy of a body is a function of the distance from it, this does not influence the relativistic potential of the body itself. From this conclusion it follows that the mass-energy of a particle in a gravitational field is anisotropic; isotropic is the mass only. Further, the possibility of an incidental feed-back between two masses is ruled out, and the law of the composition of the relativistic gravitational potentials is deduced. Finally, it is shown, by means of a simple model, that local inhomogeneities in the ideal fluid filling the Universe have negligible influence on the total potential in large regions.     

The day-to-day effects of strong geomagnetic disturbances on the North Atlantic Oscillation in the winter periods of years 1951–2003

The day-to-day effects of the strong geomagnetic disturbances on geopotential heights (GPH) in the winter lower atmosphere were described in many papers in the beginning of 1970s. These works focused on the North-East Pacific, while the North Atlantic was until now omitted. Our aim is therefore to investigate the possible effect of strong geomagnetic disturbances on the lower atmosphere GPH changes over the winter North Atlantic on the day-to-day time scale, represented by the daily index of the North Atlantic Oscillation (NAO). The investigated intervals are winter periods (December-March) of 1951–2003. The daily NAO average values in 3-day intervals before and after the disturbance onsets are compared. The graphs of NAO differences are complemented by the maps of GPH differences. The NAO response to geomagnetic disturbance, as registered on the day-to-day time scale, also shows a change in its behaviour around the year 1970. This response reaches its highest values in the years 1951–1969, usually 2–5 days following the onset of geomagnetic disturbances. Intensity of the response depends on the disturbance intensity (the largest differences were associated with extremely strong disturbances).

     

Stratospheric Polar Vortex Splitting in December 2009

Abstract

The 2009–10 Arctic stratospheric winter, in comparison with other recent winters, is mainly characterized by a major Sudden Stratospheric Warming (SSW) in late January associated with planetary wavenumber 1. This event led to a large increase in the temperature of the polar stratosphere and to the reversal of the zonal wind. Unlike other major SSW events in recent winters, after the major SSW in January 2010 the westerlies and polar vortex did not recover to their pre-SSW strength until the springtime transition. As a result, the depletion of the ozone layer inside the polar vortex over the entire winter was relatively small over the past 20 years. The other distinguishing feature of the 2010 winter was the splitting of the stratospheric polar vortex into two lobes in December. The vortex splitting was accompanied by an increase in the temperature of the polar stratosphere and a weakening of the westerlies but with no reversal. The splitting occurred when, in addition to the high-pressure system over northeastern Eurasia and the northern Pacific Ocean, the tropospheric anticyclone over Europe amplified and extended to the lower stratosphere. Analysis of wave activity in the extratropical troposphere revealed that two Rossby wave trains propagated eastward to the North Atlantic several days prior to the vortex splitting. The first wave train propagated from the subtropics and mid-latitudes of the eastern Pacific Ocean over North America and the second one propagated from the northern Pacific Ocean. These wave trains contributed to an intensification of the tropospheric anticyclone over Europe and to the splitting of the stratospheric polar vortex.     

On a physical mechanism for extra mixing in globular cluster red giants

For the first time we propose a real physical mechanism for 'extra mixing' in red giants that can quantitatively interpret all the known star-to-star abundance variations in globular clusters. This is Zahn's mechanism. It considers extra mixing in a radiative zone of a rotating star as a result of the joint operation of meridional circulation and turbulent diffusion. It is shown that the only free parameter, the angular velocity at the base of the convective envelope, can be so adjusted as to fit the observed abundance correlations without leading to a conflict with available data on rotation velocities of blue horizontal branch stars in the same cluster. There are two critical assumptions in our model, that the top of the radiative zone is not in synchronous rotation with the stellar surface but rotates significantly faster and that the criterion for shear instability takes a particular form. These will eventually be tested by three-dimensional hydrodynamical simulations.     

Palygorskite from cave sediments: case study from Wadi Haqil,United Arab Emirates

The x-ray powder diffraction identification of clay minerals both in bulk samples and in separated clay fraction confirmed the presence of palygorskite in samples of cave sediments from Wadi Haqil (the western slopes of Musandam Mountains; Ras Al-Khaimah Emirate, UAE). Samples contain quartz, gypsum, smectite, kaolinite, calcite, and palygorskite, some of them chlorite, illite, feldspars, and goethite. Calcite dominates in most samples; smectite prevails in clay fraction. After heating, the 001 reflection of chlorite shifts to higher diffraction angles and its intensity decreases; these features indicate that the chlorite represent a Fe-dominant species. Unit-cell dimensions of major phases as refined by the Rietveld method are in agreement with literature data. Chemical composition of palygorskite was derived from unit-cell dimensions as follows: MgO content is 11–14 wt% and Al₂O₃ 10–13 wt%. Clay mineralogy is only hard to ascertain from the scanning electron microscope (SEM) images even after being combined with the energy-dispersive spectrometer data. The SEM was also used to characterize gypsum grains; they often display flow deformation features. Studied cave sediments represent palygorskite-bearing weathering products and desert soils re-deposited from the cave surroundings by slope processes and wind and/or surface runoff. The mixture with other clay minerals, quartz, feldspars, etc. supports this interpretation. Fine-grained quartz fraction is probably wind-blown. Gypsum and calcite are the precipitates (crusts and/or cements), although gypsum can also be re-deposited from omnipresent gypsum-cemented surface sediments.     

Landslide databases in the Geological Surveys of Europe

Landslides are one of the most widespread geohazards in Europe, producing significant social and economic impacts. Rapid population growth in urban areas throughout many countries in Europe and extreme climatic scenarios can considerably increase landslide risk in the near future. Variability exists between European countries in both the statutory treatment of landslide risk and the use of official assessment guidelines. This suggests that a European Landslides Directive that provides a common legal framework for dealing with landslides is necessary. With this long-term goal in mind, this work analyzes the landslide databases from the Geological Surveys of Europe focusing on their interoperability and completeness. The same landslide classification could be used for the 849,543 landslide records from the Geological Surveys, from which 36% are slides, 10% are falls, 20% are flows, 11% are complex slides, and 24% either remain unclassified or correspond to another typology. Most of them are mapped with the same symbol at a scale of 1:25,000 or greater, providing the necessary information to elaborate European-scale susceptibility maps for each landslide type. A landslide density map was produced for the available records from the Geological Surveys (LANDEN map) showing, for the first time, 210,544 km² landslide-prone areas and 23,681 administrative areas where the Geological Surveys from Europe have recorded landslides. The comparison of this map with the European landslide susceptibility map (ELSUS 1000 v1) is successful for most of the territory (69.7%) showing certain variability between countries. This comparison also permitted the identification of 0.98 Mkm² (28.9%) of landslide-susceptible areas without records from the Geological Surveys, which have been used to evaluate the landslide database completeness. The estimated completeness of the landslide databases (LDBs) from the Geological Surveys is 17%, varying between 1 and 55%. This variability is due to the different landslide strategies adopted by each country. In some of them, landslide mapping is systematic; others only record damaging landslides, whereas in others, landslide maps are only available for certain regions or local areas. Moreover, in most of the countries, LDBs from the Geological Surveys co-exist with others owned by a variety of public institutions producing LDBs at variable scales and formats. Hence, a greater coordination effort should be made by all the institutions working in landslide mapping to increase data integration and harmonization.