The energy spectrum of UHECRs is discussed on the basis of the Yakutsk array database analysis. In the region E=0.1 to 30 EeV the showers are detected under trigger-500, while at energies above 30 EeV the whole acceptance area for trigger-1000 is used in order to utilize all the data available in the region of GZK cutoff.Comment: Invited talk at CRIS2004: GZK and surroundings, Catania, Italy, 31.05.04. To appear in Nucl. Phys. B Proc. Supp

The objective of this paper is to consider the main border issues and cross-border relationships in Central and East Europe (CEE) in the context of changing theoretical approaches to border studies. The authors start by analysing the impact of the impressive progress in the theory of borders on studies of CEE. Fundamental political changes in this part of Europe after 1989 were associated with the opening of borders and the intensification of cross-border cooperation, which have radically transformed the functions of boundaries. Emerging cross-border regions became spaces of communication, interaction, innovations and development. The EU enlargement to the east and the inclusion of most CEE countries in the Schengen zone accelerated the processes of re-and de-bordering and the diversification of the functions and regime of borders. The powerful waves of migration to the European Union over recent years have again greatly modified the situation in border areas and provoked the construction of new walls. In conclusion the authors propose eight research questions for future studies of borders and bordering in CEE.

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The Earth's magnetic field effect on the azimuthal distribution of extensive air showers (EAS) of cosmic rays has been evaluated using a bulk of the Yakutsk array data. The uniform azimuthal distribution of the EAS event rate is rejected at the significance level 10 -14 . Amplitude of the first harmonics of observed distribution depends on zenith angle as A 1 ≈ 0.2×sin 2 θ and is almost independent of the primary energy; the phase coincides with the magnetic meridian. Basing upon the value of measured effect, the correction factor has been derived for the particle density depending on a geomagnetic parameter of a shower. . In [4 a, b] it was shown that the showers initiated by extremely high energy photons have to show the north-south asymmetry. But the last effect has a threshold for the primary energy: E γ > 3⋅10 19 eV. In this paper we draw attention to the fact that due to the LDF asymmetry depending on χ, one can select the showers of equal energy and zenith angle in order to obtain the azimuthal modulation of the EAS event rate because of the different LDF stretch which causes the different observed primary cosmic ray energy and intensity.

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