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Изложены результаты исследований относительно обоснования перспективного многопараметрического типоразмерного ряда мобильных энергетических средств сельскохозяйственного назначения, главными параметрами которого есть номинальное тяговое усилие, мощность установленного двигателя и уровень универсальности.
Engineering geodesy deals with a wide range of problems. There is also a part that deals with measuring displacements and deformations of engineering objects. Correct geodetic monitoring requires identifying the movement of points representing an engineering object in order to determine displacement values, taking into account the time function. The paper presents the results of research on kinematic models of geodetic networks in the aspect of using them for describing the state of vertical displacements of engineering objects located on expansive soil. The paper presents two functional models of an observation system: one in the form of a second rank polynomial and the other in the form of an exponential function. The selected kinematic models of measurement-control geodetic networks were estimated with classic methods and neural networks.
Increasing production of free radicals in organisms is one of the putative mechanisms by which a extremely low frequency magnetic field (ELF-MF) may affect biological systems. The present study was designated to assess if ELF-MF applied in the magnetotherapy, affects generation of reactive oxygen species (ROS) in heart tissue and antioxidant capacity of plasma according to its working time. The experiments were performed on 3 groups of animals: group I - control; group II - exposed to 40 Hz, 7 mT, 30 min/day for 14 days (this field is commonly applied in magnetotherapy); group III - exposed to 40 Hz, 7 mT, 60 min/day for 14 days. Control rats were housed in a separate room without exposure to ELF-MF. Immediately after the last exposure, blood was taken from the tail vein and hearts were removed under anesthesia. The effect of the exposure to ELF-MF on oxidative stress was assessed on the basis of the measurements of thiobarbituric acid reactive substances (TBARS), hydrogen peroxide (H2O2), total free sulphydryl groups (-SH groups) and reduced glutathione (GSH) concentrations in heart homogenates. The total antioxidant capacity of plasma was measured using ferric reducing ability method (FRAP). Exposure to ELF-MF (40 Hz, 7 mT, 30 min/day for 2 weeks) did not significantly alter tissue TBARS, H2O2, total free -SH groups, reduced glutathione (GSH) and total antioxidant capacity of plasma. By contrast, ELF-MF with the same frequency and induction but used for 60 min/day for 14 days caused significant increase in TBARS and H2O2 concentration (P<0.01) and decrease in the concentration of GSH (P<0.05) and total free -SH groups in heart homogenates. Moreover, exposure of rats to ELF-MF (40 Hz, 7 mT, 60 min/day for 2 weeks) resulted in the decrease of plasma antioxidant capacity. Our results indicate that effects of ELF-MF on ROS generation in the heart tissue and antioxidant capacity of plasma depend on its working time.
Experiments were conducted to determine full range of tolerated and optimal water condition for eggs incubation of three species from genus Leuciscus i.e: dace Leuciscus leuciscus (L.), ide Leuciscus idus (L.), and chub Leuciscus cephalus (L.). Spawners were caught from rivers of the northern (Pasleka River drainage) and central (Pilica River drainage) parts of Poland. Fertilized eggs were incubated under controlled conditions at ten different constant temperatures ranging from 4.5 to 29.0℃. The optimal temperature ranges for the incubation of dace, ide and chub eggs were 7.5 to 12.3℃; 15.7℃ and 19.0 to 23.0℃, respectively (considering hatching percentage, incidence of abnormalities and size of hatched larvae), which are close to the water temperature during spawning season. This study also reveals that embryos of studied species can adapt to increasing water temperature due to global warming up to 23.0℃ (dace and ide) and 27.5℃ (chub). Besides, some inter-population differences in the response to temperature were observed.
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