Publications by authors named "V A Davydovych"

Orientating investigations were carried out in order to test the influence of oil extracts of lycopene (20, 40 and 60 mg/kg feed) and astaxanthin (10, 20 and 30 mg/kg feed) as feed additives on the metabolic parameters (glucose, creatinine, cholesterol) and enzyme activities (alanine aminotransferase, ALT; aspartate transaminase, AST) of laying hens. Eggs from these hens were stored at refrigerator temperatures of 4°C and 12°C for up to 30 days and analyzed for vitamin A, carotenoid and yolk color. 45 laying hens (Hy-Line W36 cross, 23 weeks of age) were divided in three groups of 15 birds each (control, lycopene fed group, astaxanthin fed group).

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The known three-component reaction-diffusion system modeling competition and co-existence of different language speakers is under study. A modification of this system is proposed, which is examined by the Lie symmetry method; furthermore, exact solutions in the form of traveling fronts are constructed and their properties are identified. Plots of the traveling fronts are presented and the relevant interpretation describing the language shift that has occurred in Ukraine during the Soviet times is suggested.

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