On bosonic limits of two recent supersymmetric extensions of the Harry Dym hierarchy

Two generalized Harry Dym equations, recently found by Brunelli, Das and Popowicz in the bosonic limit of new supersymmetric extensions of the Harry Dym hierarchy [J. Math. Phys. 44:4756--4767 (2003)], are transformed into previously known integrable systems: one--into a pair of decoupled KdV equations, the other one--into a pair of coupled mKdV equations from a bi-Hamiltonian hierarchy of Kupershmidt.Comment: 7 page

Theoretical backgrounds of durability analysis by normalized equivalent stress functionals

Generalized durability diagrams and their properties are considered for a material under a multiaxial loading given by an arbitrary function of time. Material strength and durability under such loading are described in terms of durability, safety factor and normalized equivalent stress. Relations between these functionals are analysed. We discuss some material properties including time and load stability, self-degradation (ageing), and monotonic damaging. Phenomenological strength conditions are presented in terms of the normalized equivalent stress. It is shown that the damage based durability analysis is reduced to a particular case of such strength conditions. Examples of the reduction are presented for some known durability models. The approach is applicable to the strength and durability description at creep and impact loading and their combination

The influence of the sea on the economic development and settlement structure in the Baltic Sea region

Earliest studies into the influence of the sea on the economy and settlement structure date back to the mid-19th century. They became common in the 20th century. Researchers have come to a general understanding that a coastal position has a beneficial effect on the development of regions. Such areas have a denser population and develop more rapidly than inland regions. At the same time, the effect of environmental, socioeconomic, demographic, and political factors is often stronger than the influence of the sea. Thus, an inland position can be more beneficial than a coastal one. Both trends are observed in the Baltic Sea macroregion. However, the ‘gravitational force’ of the sea varies from place to place. This article focuses on the most significant differences between territories and countries. These differences reflect the uneven influence of the proximity of the Baltic Sea on the development of population and national economies. Qualitative differences between mesoregions are measured using a combination of theoretical and empirical typologies. An economic, statistical, and cartographic analysis helps to identify a special type of mesoregions — coastal development corridors, which make an important contribution to the economic development and consolidation of the Baltic macroregion. In transnational macroregions, such typological differences must be taken into account in strategic and spatial planning at the intergovernmental level

A revised approach to the ?<i>o</i>F2 long-term trends analysis

International audienceA new approach to extract foF2 long-term trends, which are free to a great extent from solar and geomagnetic activity effects, has been proposed. These trends are insensitive to the phase (increasing/decreasing) of geomagnetic activity, with long-term variations being small and insignificant for such relatively short time periods. A small but significant residual foF2 trend, with the slope Kr = - 2.2 × 10-4 per year, was obtained over a 55-year period (the longest avail-able) of observations at Slough. Such small trends have no practical importance. On the other hand, negative (although insignificant) residual trends obtained at 10 ionosonde stations for shorter periods (31 years) may be considered as a manifestation of a very long-term geomagnetic activity increase which did take place during the 20th century. All of the revealed foF2 long-term variations (trends) are shown to have a natural origin related to long-term variations in solar and geomagnetic activity. There is no indication of any manmade foF2 trends. Key words. Ionosphere (ionosphere-atmosphere interactions, ionospheric disturbances