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Tbilisi, Georgia

The Georgian National Academy of science is a main learned society of the Georgia. It was named Georgian SSR Academy of science until November 1990. The Academy coordinates scientific research in Georgia and develops relationship with the academies and scientific centers of foreign countries. Wikipedia.


Gil A.,Siedlce University Of Natural Sciences And Humanities | Alania M.V.,Siedlce University Of Natural Sciences And Humanities | Alania M.V.,Georgian Academy of Sciences
Journal of Atmospheric and Solar-Terrestrial Physics | Year: 2011

We study temporal changes of the rigidity (R) spectrum of the harmonics of the 27-day variation of the galactic cosmic ray (GCR) intensity using neutron monitors (NM) data for the period 1965-2002. We show that the rigidity spectrum of the third harmonic (9 days) of the 27-day variation of the GCR intensity changes in a similar way as the spectra of the first and second harmonics, being hard in the maximum epochs and soft in the minimum epochs of solar activity. We ascribe this finding to the alternation of the sizes of the modulation regions of the 27-day variation of the GCR intensity in different epochs of solar activity. The average size of the vicinity of the corotating interaction regions, causing the 27-day variation of the GCR intensity, is less in the minimum epochs than in the maximum epochs of solar activity. A vicinity of the corotating interaction regions of larger size involves in modulation higher rigidity particles of GCR than the vicinity of smaller size; thus, this statement can be considered as one of the reasons leading to the hardening of the rigidity spectrum of the harmonics of the 27-day variation of the GCR intensity in maximum epochs compared with minimum epochs of solar activity.We also show that the temporal changes of the power rigidity spectrum of the third harmonic of the 27-day variation of the GCR intensity are negatively correlated with the rigidity spectrum of the 11-year variation of the galactic cosmic ray intensity.We found a recurrence in the temporal changes of the amplitudes of the first harmonic of the 27-day variation of the GCR intensity and in some parameters of solar activity and solar wind. © 2010 Elsevier Ltd. Source


Blankleider B.,Flinders University | Kvinikhidze A.N.,Georgian Academy of Sciences | Silagadze Z.K.,Novosibirsk State University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

We construct the gauge invariant three-photon decay amplitude of particle-antiparticle bound states modeled by the Dyson-Schwinger and Bethe-Salpeter equations. Application to the quark-antiquark (qq¯) bound states is emphasized. An essential aspect of our formulation is that it applies to any underlying quantum field theoretic model of the qq¯ system, and not just to models, like exact QCD, where the quark self-energy Σ couples to the electromagnetic field solely via dressed quark propagators. In this way, applications to effective field theories and other QCD motivated models are envisioned. The three-photon decay amplitude is constructed by attaching currents to all possible places in the Feynman diagrams contributing to the dressed quark propagator. The gauge invariance of our construction is thus a direct consequence of respecting the underlying structure of the quantum field theory determining the dynamics. In the resultant expression for the three-photon decay amplitude, all the basic ingredients consisting of the bound-state wave function, the final-state interaction qq¯ t matrix, the dressed quark propagator, and dressed quark currents, are determined by a universal Bethe-Salpeter kernel. © 2015 American Physical Society. Source


Inagaki T.,Hiroshima University | Kimura D.,Hiroshima University | Kohyama H.,Chung Yuan Christian University | Kvinikhidze A.,Georgian Academy of Sciences
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

Regularization dependence of the Nambu-Jona-Lasinio model leaves room for improvement. To help in choosing a suitable regularization scheme, we investigate the phase diagram on the temperature-chemical potential plane in the Nambu-Jona-Lasinio model with the dimensional regularization. While the structure of the resulting diagram shows resemblance to the one in the frequently used cutoff regularization, some results of our study indicate a striking difference between these regularizations. Diagrams in the dimensional regularization always indicate the first-order phase transition at high chemical potential, while the first-order transition does not occur in the cutoff method for some parameter sets. © 2012 American Physical Society. Source


Alania M.V.,Siedlce University Of Natural Sciences And Humanities | Alania M.V.,Georgian Academy of Sciences | Wawrzynczak A.,Siedlce University Of Natural Sciences And Humanities
Advances in Space Research | Year: 2012

We show that rigidity spectrum of Forbush decrease (Fd) of galactic cosmic ray (GCR) intensity in September 9-23, 2005 clearly depends on energy. We calculated rigidity spectrum of the Fd based on the neutron monitors and Nagoya muon telescope channels' data divided in three groups according to their cut off rigidities. We found that temporal changes of rigidity spectrum exponent γ are approximately similar for all cut off rigidity groups, but γ values are the larger the higher are cut off rigidities. We conclude that rigidity spectrum of Fd is hard for lower energy range and is soft for the higher energy range. We believe that an energy dependence of the power law rigidity spectrum of Fd is observed owing to the preferential convection-diffusion mechanism during Fd in September 9-23, 2005. It is a reflection of an influence of the temporal changes of the structure of the interplanetary magnetic field (IMF) turbulence in different range of frequency f during Fd. Particularly, a decisive role in formation of the character of the rigidity spectrum belongs to the changes of the exponent ν of the power spectral density (PSD) of the IMF turbulence (PSD ∝ f -ν). The exponent ν is greater for high frequency region of the IMF turbulence (responsible for scattering of low rigidity particles of GCR), than for low frequency region of the IMF turbulence (being responsible for scattering of higher rigidity particles). Also, we challenge to estimate an existence of slab/2D structure of solar wind turbulence during the Fd in September 9-23, 2005 based on the distribution of average turbulence energy among the IMF's components. Source


Sanadze G.A.,Georgian Academy of Sciences
Russian Journal of Plant Physiology | Year: 2010

Various aspects in photobiosynthesis of isoprene and its release from leaves into the environment are presently well known. The release of isoprene from the cell can be regarded as dissipation of excess energy (entropy). The systemic release of metabolites into the external medium should be considered as a result of cell excretory activity, one of the most important functions of living systems. Energy dissipation terminates the sustained passage of thermodynamic flows and regulates the overall stability of cell stationary condition. These issues are considered in this review from the standpoint of contemporary thermodynamics. It is concluded that the excretory capacity of living cell is based on thermodynamic dissipation of entropy during irreversible processes that provide for stability and sustainable development of the living organism. © Pleiades Publishing, Ltd., 2010. Source

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