7,225 research outputs found
Middle Atmosphere Temperature and Dynamics as Revealed from D-region Observations
The concept of so-called meteorological control of the ionospheric D-region is presently undergoing development. According to this concept the electron concentration in this region is governed not only by solar and geomagnetic parameters but strongly depends on the temperature and dynamical regime of the mesosphere and stratosphere. How this connection between D-region and meteorological parameters can be used to obtain some information about middle atmosphere temperature and dynamics is examined. The essential points of the meteorological control concept are reviewed and the influence of turbulence on nitric oxide distribution and thus the ion production rate is discussed
Second experiment on the investigation of ion-molecular reaction constants directly in the ionosphere
Ionospheric ion-molecular interaction
Rates of Basic Ion-molecular Processes in the Ionosphere
Literature review on basic ion-molecular reaction rates in ionospher
General overview of the solar activity effects on the lower ionosphere
Solar activity influences the ionospheric D region. That influence manifests itself both in the form of various solar induced disturbances and in the form of the D region dependence on solar activity parameters (UV-flux, interplanetary magnetic field, solar wind etc.) in quiet conditions. Relationship between solar activity and meteorological control of the D region behavior is considered in detail and examples of strong variations of aeronomical parameters due to solar or meteorological events are given
Discrete convexity and unimodularity. I
In this paper we develop a theory of convexity for a free Abelian group M
(the lattice of integer points), which we call theory of discrete convexity. We
characterize those subsets X of the group M that could be call "convex". One
property seems indisputable: X should coincide with the set of all integer
points of its convex hull co(X) (in the ambient vector space V). However, this
is a first approximation to a proper discrete convexity, because such
non-intersecting sets need not be separated by a hyperplane. This issue is
closely related to the question when the intersection of two integer polyhedra
is an integer polyhedron. We show that unimodular systems (or more generally,
pure systems) are in one-to-one correspondence with the classes of discrete
convexity. For example, the well-known class of g-polymatroids corresponds to
the class of discrete convexity associated to the unimodular system A_n:={\pm
e_i, e_i-ej} in Z^n.Comment: 26 pages, Late
The Russian corporation: patterns of behavior during the crisis
This paper considers the behavior patterns of Russian firms before and during the financial crisis of 2008-2009. To facilitate comparison, we define three main
groups of actors at the firm level in the Russian economy – large, politically connected companies; mid-size firms that expanded in the 2000s with the help of administrative support, and successful mid-size firms driven by market factors.
Many of the large companies practiced highly risky financial policy and experienced a decrease in efficiency before the crisis, and the managers and owners of some Russian firms have been engaging in opportunistic behavior
during the crisis; the forms and causes of this behavior are analyzed here. We conclude by proposing some policy implications with emphasis on supporting successful mid-size firms driven by market factors
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