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Medvinsky A.B.,Institute of Theoretical and Experimental Physics | Adamovich B.V.,Belarussian State University | Chakraborty A.,Central University of Rajasthan | Lukyanova E.V.,Belarussian State University | And 5 more authors.
Ecological Complexity | Year: 2015

Population abundance exhibits large fluctuations over time. Whether these irregular oscillations are driven by random environmental factors or a suite of deterministic mechanisms is an unsettled question in theoretical ecology. In this connection, one prevalent view is that at least part of the apparent disorder, which is known as deterministic chaos, is caused by deterministic interactions between species and/or some external periodic forcing. Disentangling this chaotic dynamics from environmental noise in field data remains problematic, however. Recent attempts to find chaos in the wild resulted in the conclusion that a great majority of populations live at a boundary between chaotic and regular dynamics, i.e. on the edge of chaos. Parallel to that result, we report here that chaos is an inherent dynamic phenomenon, which can emerge far away from the edge of chaos in a natural population. We have observed that the plankton dynamics in the Naroch Lakes, Belarus, exhibit chaos with the horizon of predictability of around 2.5 months, and the corresponding dominant Lyapunov exponent equals approximately 0.4, thus laying out of the narrow interval between -0.1 and +0.1 characteristic of living at the edge of chaos. Furthermore, we have found that the second order Renyi entropy can be considerably greater than the values of the dominant Lyapunov exponents. It implies that the plankton dynamics can be characterized by at least two physical degrees of freedom, and the qualitative description of irregular changes in plankton abundance requires a four- or higher-dimensional phase space. In other words, interspecific interactions across trophic levels can significantly contribute to the emergence of chaos far away from the edge of chaos. © 2015 Elsevier B.V.

Tashlykov I.,Belarussian State Pedagogical University | Turavets A.,Belarussian State Pedagogical University | Zhukowski P.,Lublin University of Technology
Acta Physica Polonica A | Year: 2011

The investigation of influence of Xe+ ions irradiation of graphite on its surface topography and wettability was conducted. With the increase of the irradiation dose, the roughness average increases rapidly at first (when the sample was irradiated at the dose of 1 × 1014 cm-2) and then decreases slowly. The atomic force microscopy three-dimensional pictures showed that after irradiation of graphite of Xe+ ions with a dose of 3 × 1015 cm-2 hemispherical grains (from 0.2 to 0.8 μm in diameter) appear on its surface. Surface water contact angle measurement showed that irradiation of graphite by Xe+ ions leads to a hydrophobic surface of graphite. We have observed that irradiation of graphite by Xe+ ions can be used for obtaining graphite surface with desirable topography and water wettability.

Egorov V.V.,Belarussian State University | Lyaskovskii P.L.,Belarussian State University | Taribo M.G.,Belarussian State University | Nazarov V.A.,Belarussian State University | And 3 more authors.
Journal of Analytical Chemistry | Year: 2010

Selectivity coefficients of ion-selective electrodes on the basis of liquid anion exchangers, a quaternary phosphonium salt, and 20 higher quaternary ammonium and other nitrogen-containing salts differing in the length of hydrocarbon radicals, the nature of the quaternary nitrogen atom, and the presence of polar groups near to the exchange center with respect to 17 mineral, organic, and metal complex anions are presented. The effect of the nature of the anion-exchanger on the anion selectivity is discussed. © 2010 Pleiades Publishing, Ltd.

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